Showing posts with label Textile Research. Show all posts
Showing posts with label Textile Research. Show all posts

Siro And Two-Fold Yarns

Investigation was carried out on how the tensile and related properties of Siro yarns, spun from two separated rovings of different types of materials, were affected by the twist factor and draft. Comparison on Siro yarns and two-fold yarns of the same linear density and twist factor revealed that the former was better in tensile strength and related properties. The Siro yarns are believed to be able to bear extra tension during manufacturing processes such as weaving and knitting.

Keywords : yarn strength, evenness, imperfections, hairiness.

1. INTRODUCTION

In Siro spinning, two parallel fibre strands, separated at a distance, are drafted simultaneously in the drafting zone. After they emerge from the front roller nip, they converge to form a yarn by twisting. Previous researches") mostly focused on studying spinning geometry and yarn parameters for producing yarn from rovings of the same fibre type. There has been very limited information available regarding the use of rovings of two different kinds of materials on the Siro system. Thus, the present work was designed to carry out some spinning trials on attenuating two rovings of different fibre materials in the drafting zone and to investigate the capability of the resulting Siro yarn.

In staple yarns, twist is essential to hold the fibres together and to impart some degree of cohesiveness to the structure. Twist is a means by which a bundle of fibres is held together so that the ultimate structure is made capable of withstanding the stresses and strains generated in the next manufacturing steps. The role of twist in yarn is essential to manipulate the yarn properties. Thus, the influence of twist on the Siro spun yarn tensile strength was also included in the present work.

2. EXPERIMENTATION 2.1. Selection of materials

Wool, polyester and acrylic fibres were selected for the study. The characteristics of the fibres are shown in Table 1. All samples prepared for the present work were conditioned and tested under standard atmospheric conditions ( 20 + 2°C and 65 ±2 % relative humidity).

The Instruments for testing the fibre properties are listed in Table 2. The processing parameter used in drawing and roving are shown in Table 3. Table 4 gives the sequence of machinery used to produce the yarns.

2.2. Production of two-fold yarn

Comparison was made between Siro and two-fold yarns of the same linear density. A worsted twist factor of 2.2 [2600 (tpm x -qtex)] was adopted. This enabled the advantages of Siro yarn to be compared with those of two-fold yarn. Comparison was also made between the yarns of different linear density, to identify the effect of changes in draft on the properties of the two series of yarns.

Since the folded twist of the two-ply yarn should be equal to that of its corresponding Siro yarn, and the folded twist of a two-ply yarn is usually set at 70% of that of the single yarn, it is necessary to calculate the required twist that should be inserted into the single yarn by dividing the folded twist by 70%. Table 5 shows the required amount of twist inserted into the yarns.

3. RESULTS

The properties of the Siro and two-fold yarns are compared in Tables 6-9. 3.1. Comparison and•evaluation amongst Siro and two-fold yarns

Referring to Table 6, for pure wool worsted yarns, when the yarn linear density increased from 40 tex to 70 tex, the tenacity of the two-fold yarns increased from 7.8 to 8.3 cN/tex while that of the Siro yarns increased from 6.7 cN/tex at 40 tex, 8.5 at 60 tex to 8.7 at 70 tex. The Siro yarns, except for the 40 tex, were significantly stronger than the two-fold yarns, by 4.7% to 14.9% at twist factor 2.2. The breaking extension of Siro yarns was also significantly better than that of the two-fold yarns, by 60% to 73%. The evenness of the two-fold yarns was better than that of Siro yarns. At the twist factor of 2.2, Siro yarns were significantly less hairy than the two-fold yarns, by 10% to 18%.

For the wool/acrylic blended yarns, in referring to Table 7, the tenacity of two-fold yarns increased from 9.7 cN/tex at 40 tex, to 11.0 at 60 tex and 11.6 at 70 tex. Tenacity of the Siro yarns increased from 13.3 to 15.4 cN/tex. The Siro yarns were significantly stronger than the two-fold yarns, by 32% to 37%. The breaking extension of the Siro yarns was higher than that of two-fold yarns, by 56% to 125%. The evenness of the Siro yarns was better than that of two-fold yarns. The yarn evenness CV% of the two-fold yarn ranged from 15.8 at 40 tex to 13.1 at 70 tex while the evenness CV% of the Siro yarns decreased from 15.5 to 11.9 as the yarn linear density increased. The hairiness of the Siro yarn was lower than that of the two­fold yarn, by 44% to 50%.

From Table 8, it can be seen that the tenacity of wool/polyester Siro yarn was higher than that of the two-fold yarn, by 6% to 23%. The tenacity of the two-fold yarns increased from 13.9 cN/tex at 40 tex, 14.9 at 60 tex to 15.8 at 70 tex. The tenacity of Siro yarns increased sharply from 14.8 to 19.5 cN/tex. The breaking extension of the Siro yarns was higher than that of the two-fold yarns, by 3% to 20%. The evenness of the Siro yarns was also better than that of the two-fold yarns. The evenness of the Siro yarns and two-fold yarns ranged from 17.6 at 40 tex to 12.6 at 70 tex and from 18.6 at 40 tex to 13.9 at 70 tex, respectively. The Siro yarns were significantly less hairy than the two-fold yarns, by from 30% to 41%.

For the synthetic (acrylic/polyester) fibre blended yarns (Table 9), the tenacity of the two-fold yarns increased sharply from 15.4 to 22.3 cN/tex as the linear density increased from 40 tex to 70 tex. The Siro yarn again exhibited better tensile strength, by 4% to 27%, compared to the two-fold yarns; it increased from 21.0 cN/tex at 40 tex, 22.5 at 60 tex to 23.2 at 70 tex. The breaking extension was generally higher for the Siro yarns. The evenness CV% of the Siro yarns decreased from 14.3 to 12.2, and that of the two-fold yarns decreased from 14.2 to 12.9, as the yarn linear density increased. The two-fold yarns were more hairy than the Siro yarns. The hairiness of the two-fold yarns increased from 11.6 to 12.0 and the hairiness of the Siro yarns increased from 6.8 to 6.9 as the linear density increased from 40 tex to 70 tex.

4. DISCUSSION

The present work focused on a comparison of the yarn properties of Siro yarns and two-fold yarns of equivalent yarn linear density. It was found that the Siro yarns were generally superior to the two-fold yarns in terms of yarn strength.

The breaking strength of the Siro yarn is higher than that of the two-fold yarns of equivalent linear density due to the particular Siro yarn structure - due to the fibres being more firmly bound within the yarn structure. The two twisted strands of the drafted fibres caused some surfaces fibres to be trapped into the Siro yarn so as to increase the inter-fibre cohesion in the yarn which can withstand higher breaking forces. In Siro spinning, the sense of twist is the same for both the single ends and the composite product. This gives a yarn that is somewhat more compact , with a firmer core, than the usual two-fold yarn with opposing singles and folding.

The better tenacity of Siro yarn could also be ascribed to the fact that the single strands have comparatively low twist which results in better and more even load sharing by the constituent fibres. In the process of yarn formation, fibres distribution is subjected to the twisting operation. The combination of varying numbers of fibres per cross section with varying forces binding these fibres together because of twist variation leads to varying tensile properties.

Another relevant factor with respect to the inferior yarn strength of two-fold yarns is the additional freedom of lateral movement permitted to the fibres. During extension of the yarn, the plies become grossly deformed r.nd the lateral displacement of fibres at different initial positions appear to follow a complex pattern. Fibres initially in the centre of the plies begin to move towards the central yarn axis. Fibres at greater initial radial positions in the plies simultaneously begin to gather around their own ply axis which is already moving independently towards the yarn axis.

The Siro yarns generally also performed better than the two-fold yarns in terms of evenness and degrees of imperfections. This is because the Siro yarn is produced by two strands of roving ; there would be a better parallel and straightening effect between the separated fibre strands during drafting. Since peripheral distribution of fibres during spinning is a combined effect governed to a large extent by the staple length, fibre cross-sectional resistance to twisting and other process parameters, it would not be possible to deduce the exact relationship of the combined fibre parameters and yarn unevenness. The poorer uniformity of the two-fold yarns may also be due to the greater number of production processes involved in producing two-fold yarns as compared to Siro yarns.

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K.P.S. Cheng & C.H. Yuen

Institute of Textiles and Clothing, The Hong Kong Polytechnic University

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CONTROL OF LAP AND CARD SLIVER EVENNESS AND CARD WEB NEPS WITH MECHANICAL VARIABLES AT SCUTCHER

 

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Different setting points of scutcher i.e. feed roller to krischner beater, krischner beater to stripping rail and grid bar gauges
were changed and their effect on lap evenness, card sliver evenness, and card sliver neps was observed. It was noted that feed
roller to krischner beater and krischner beater to stripping rail for evenness and all the setting points for sliver neps showed

highly significant differences in the mean values for different settings. Key words: lap evenness, scutcher settings, sliver evenness

INTRODUCTION

Cotton delivered by the opening machinery to the scutcher is well opened and usually arrives in the form of large tufts. Scutching is a process of cleaning by striking the cotton from a pair of rolls to a rapidly revolving beater after which it is formed into a continuous sheet of small tufts of cotton, held together by compression. The objectives of the scutching operation are: first, to continue the opening of the cotton even further than has already been done; second, to clean the cotton of more of the heavier dirt and undesirable short fibres; third, to form this cleaned cotton into a continuous sheet called a "Lap"; and fourth to make this lap as uniform as possible. The scutcher section may be classified as: feed unit, beater section, screen section and lap head. With improvements in trash extraction at earlier stages of processing, the extraction of trash at scutcher has been of less importance than making a uniform well textured lap. Khan (1972) found that regularity of sliver is dependent upon the uniformity of scutcher lap. Shrigley (1973) reported that incorrect setting of stripping rail is detrimental to lap regularity. Ratnam and Seshan (1987) mentioned that the short term variation in card sliver contributes 3.2% of the total, provided the sliver is regular. Variation introduced by cards together with the variation in blow room, a major part of this variation, can be attributed to blow room. Almashouley (1988), reported that inadequate settings and inadequate feedings are the sources of variation in weight per yard of lap. Alan and Alexander (1988) pointed out that processing of fibres tends to produce neps through a stress build up/sudden release mechanism which induced buckling along the fibre length. Ali (1998) reported that calender rolls pressure. kirschner beater gauges and kirschner beater speed mainly influenced the lap weight variation. He also recommended that CV of meter to meter lap weight be strictly controlled and maintained at level less than 2%. Anonymous (1999) recommended that distance between stripping rail and the kirschner beater should be 2mm. In case. distance between rail and beater is greater, this will badly influence flow of material and cause soft lap. Robert e at. (2000) observed that considerable amounts of short fibre content. created in production and processing, are removed

in the combing process. This study was undertaken to determine the effect of different setting points of scutcher on lap and card sliver evenness and card sliver neps.

MATERIALS AND METHODS

Lint cotton samples of Punjab American cotton variety MNH-93 were collected from the running material at M/S Nishat Mills Ltd., Faisalabad. The raw cotton samples were subjected to following physical tests:

Spinning Procedure: The samples were processed at Ohara
Hergath blow room line (Model 1988) with the following

changes at scutcher in blow room.

i. Feed roller to kirschner beater gauge: F1 =3 mm, F2=5 mm, F3= 7 mm

ii. Kirschner beater to stripping rail gauge: S,=2 mm.

S2=3 mm, S3=4 mm

iii. Kirschner beater grid bar gauge: G1=5 mm, G2= 7 mm,

G3= 9 mm

After every change at scuther, the samples from laps were collected and tested for the basic fibre characteristics along with the following lap quality evaluation tests:

Lap Evenness: This is yard to yard weight variation of lap and was determined by cutting it into one yard pieces then weighing each piece in grams on the weighing scale and in this way the coefficient of variation was calculated.

Sliver Evenness: Sliver evenness (U%) was determined on Uster Tester-llI according to the procedure supplied by the manufacturer, M/S Zellweger Ltd. (1995b). Uster Tester speed was set at 25 meter per minute for each test.

Card Web Neps: Neps were counted by AFIS-N according to the instructions laid down in its operational manual supplied by M/S Zellweger Ltd. (1992), Switzerland.

Three factor factorial completely randomized design was applied for testing differences among various quality characters evaluated in this study. Duncan's multiple range test was applied for individual comparison of means among various quality characteristics as suggested by Steel and Torrie (1980). The data were subjected to statistical manipulation on computer employing M-Stat computer programme designed by Freed (1992).

RESULTS AND DISCUSSION

Lap Evenness :The results pertaining to lap evenness are
shown in Table I. This Table shows that the effect of feed

roller to beater gauges, beater to stripping rail gauges and interaction F x S generate highly significant differences among mean values. The results in respect of SxG interaction also showed significant differences, while the effect of rest of gauge and interactions on lap evenness was non-significant.

The individual mean values of lap evenness recorded the best value as 0.80% at F2 followed by 0.87 and 0.93% for F3 and FI respectively while these gauges significantly differed in their mean values. Above results show that the setting F2 gives minimum lap. Similar views are given by Almashouley (1988), who reported that inadequate settings and inadequate feedings are the sources of variation in weight per yard of lap, while Ali (1998) reported that ealender rolls pressure, kirschner beater gauges and kirschner beater speed mainly influenced the lap weight variation. He also recommended that CV of meter to meter lap weight be strictly controlled and maintained at level less than 2%.

The comparison of individual means for beater to stripping rail gauges recorded the best value of 0.65% CV for SI followed by 0.85 and 1.10 % S2 and S3 respectively and recorded significant differences between the individual means. These results coincide with those of Anonymous (1999) which recommended that distance between stripping rail and the kirschner beater should be 2mm. In case, distance between rail and beater is greater, this will badly influence flow of material and cause soft lap. Likewise Shrigley (1973) reported that incorrect setting of stripping rail is detrimental to lap regularity. In case of grid bar gauges, the order for grid bar settings G3, G2 and G I was recorded as 0.85. 0.87 and 0.88 % respectively. These results indicated that the means of grid bar gauges recorded non­significant differences with respect to individual means. Sliver Evenness: The results pertaining to the sliver evenness are given in Table 2. This Table showed that the effect of feed roll to beater gauges, beater to stripping rail gauges and interaction F x S was highly significant. However, grid bar gauges and remaining interactioris were found to have non-significant effect. The individual mean values for sliver evenness between feed roller to beater gauges were recorded as 3.88, 4.12 and 4.28 % for F2, F3 and F1 respectively. Present results indicated significant differences among the individual means. These results are in line with those of Khan (1972) who found that regularity of sliver is dependent upon the uniformity of scutcher lap, while Ratnam and Seshan (1987) stated that the short term variation in card sliver contributed 3.2% of the total, provided the sliver is regular. Variation introduced by cards is in addition to the major variation caused in blow room. The comparison of individual mean values for beater to stripping rail gauges is shown in Table I. The best value of sliver evenness (3.31%) for SI was followed by S2 and S3 with respective means of 4.17 and 4.80%. These values showed significant differences among individual means indicating that the close gauge SI gave the best results for lap uniformity than for sliver uniformity, since the variation in lap leads to the variation in card sliver. These results get support from Merill (1960) who recommended that the stripping rail must be close enough to beater. Shrigley (1973) reported that incorrect setting of stripping rail is

detrimental to lap regularity. Khan (1972) found that regularity of sliver is dependent upon the uniformity of scutcher lap.

Comparison of individual means for grid bar gauges are shown in Table 2a. The individual mean values for grid bar gauges were 4.05, 4.10 and 4.13 % for G" G1 and G2 respectively, indicating that there was no effect of grid bar gauges on the regularity of card sliver.

Card Web Neps: The results pertaining to card web neps for different settings at scutcher in blow room are shown in Table 3. The results revealed that the effect of feed roller to beater gauges, beater to stripping rail gauges. grid bar gauges and interactions F x Sand S x G are highly significant, while interactions F x G and F x S x G differed significantly.

Duncan's multiple range test for comparison of individual means of card web neps for feed roller to beater gauges are shown in Table 1. The minimum web neps are recorded at F2 followed by F3 and F1 with their respective means as 80.17, 88.03 and 94.08 neps per gram. These results indicated that close gauge produced more fibre breakage and neps. Similar were the findings of Wegener (1980) who reported that neps originated from growth, harvesting, ginning, and processing and are often formed form fibre breakage. causing the fibre to coil itself, thus involving other fibres in its recoiling and producing entanglements. Similarly, Dever et at (1988) observed that neps are formed by increased aggressive cleaning. However. Alon and Alexander (1978) pointed out that processing of fibres tends to produce neps through a stress build up/sudden release mechanism which induces buckling along the fibre length.

The comparison of individual means for beater to stripping rail, gauges generated the minimum number of neps for SI followed by S2 and S3 as 69.69,88.94 and 103.65 neps per gram respectively. However, the individual means significantly differed from each other. These findings are supported by Shrigley (1973) who found that the stripping rail setting is the most important, since a setting that is too wide may permit the cotton to pass around with the beater instead of being discharged, thereby creating neps and flocking, whereas Steadman (1997) reported that neps seldom appear in boil, but every processing stage has the potential to be susceptible to fibre aggregation. When properly managed, both carding and combing can remove more neps than generated.

In case of grid bar gauges, the minimum number of neps was recorded at G3 followed by G2 and G I with their respective mean values as 85.11, 87.36 and 89.81 neps per gram. indicating significant differences between the individual means. More opening of grid bars generates more cleaning and less neps. Sheikh (1997) reported that an increase in seed, trash particles in cotton is associated with higher nep content. Herbert et at (1986) observed that three types of neps are present in cotton: i) entanglement with seed coat fragment, ii) entanglement with trash, and iii) non-fibrous material entanglement, while Harrison and Barge/on (1986) observed that neps are important in determining the quality of final product of cotton fabrics. Fibre characteristics and processing conditions are two factors that affect the nep formation.

Conclusion: The study showed that too wide stripping rail

setting with the beater may permit the cotton to pass round and round with the beater instead of being discharged which damages the fibres and generates neps, thus the rail must be close enough for proper functioning.

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Magnetic Ring-Spinning Revolutionizing the Tradition

In today’s spinning technology, at least 4 types of spinning systems are commercially available. These are the tradi­tional ring spinning, rotor spinning, airjet spinning and friction spinning. Among them, ring spinning stands alone in providing high quality yarn suitable for any type of tex­tile end product. Other more recent systems enjoy much higher production speed than traditional ring spinning, but yarn quality restricts their use to only narrow ranges of tex­tile products. The primary technological limitation of ring spinning lies in the speed of the ring-traveler system. The traveler is a C-shaped thin piece of metal that is used for a limited period of time, disposed, and replaced on frequent basis. Three specific issues must be addressed to overcome this limitation:

· the dependence of the yarn linear speed (or delivery speed) on the rotational speed of the traveler

· the continuous need to stabilize yarn tension during spinning and the dependence of this stability on the traveler speed

· the impact of traveler speed on fiber behavior in the spinning triangle

Research to date has only provided about a 15% improve­ment in traveler speed without affecting the traveler/ring contact thermal load capacity. Ring spinning is still at a production rate disadvantage of 15 to 20 times in compari­son with other spinning systems. Therefore, the challeng­ing issue is how to break the traditional paradigm of ring spinning and revolutionize its principle in such a way that very high speed can be achieved without sacrificing the tra­ditional quality of ring spun yarns.

Our design approach is to totally eliminate the traveler from the ring spinning system and replacing it with a mag­netically suspended lightweight annular disc that rotates in a carefully pre-defined magnetic field (See Figure below). By creating a non-touching environment of the rotating element for ring spinning this system provides a super high spinning rotation without the limitations of the current trav­eler system.

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Finite element system simulation

We are simulating the magnetic system using a magnetic finite element package. The magnetic field strength distri­bution on different system components shows the support­ing forces exerted on the rotor part (See Figure below).

Our first estimate is that these forces are 25 N in the radial direction and 15 N in the axial direction. We are seeking more axial stiffness of the rotor.

Contributing Graduate Students: Gangumalla Yamshi Reddy, Jayendra S. Dabahde (Auburn).

Industry Interactions: 2 [Unifi, Velcro] Academic non-NTC Interactions: 2

Project Web Address: http://www.eng.auburn.edu/~fhady/magnetic-report.htm

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Faissal Abdel-Hady, a Research Assis­tant Professor of Textile Engineering at Auburn since 1998 and an Assistant Professor of Mechanical Engineering at Ain Shams (Egypt), earned a B.S in 1975 and M. S. in 1981 there and a Ph.D. in 1988 at Ecole Nationale Superieure des Mines de Saint Etienne (France), all in mechanical engineering. Faissal then was a manager in industrial soft­ware for Hicon France. His research interests include thermal analysis. stress simulation, automatic control and mechatronics, mechanical compo­nents, CAD/CAM for filament wound structures, dynamic signal processing and software development.

S00-AE06, F01 -AE02*, S01 -AE32 fhady@eng.auburn.edu

(334)-844-5471 http://www.eng.auburn.edu/~fhady

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By replacing the traveler in ring spinning
with a disc that rotates in a magnetic field,
we hope to maintain
the high quality of ring spun yarn,
but at much higher speeds.

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EFFECT OF BLENDING RATIOS AND TECHNIQUES ON THE QUALITY PARAMETERS OF 30'S POLYESTER/COTTON YARN

The present study was conducted to determine the impact of polyester/cotton ratio on the quality characteristics of yarn. The quality characters depend upon the ratio of polyester and cotton in the blend and also on the blending technique adopted during fibre production to yarn spinning. The quality characters such as single yarn strength, yarn elongation and rupture per kilometer of yarn were directly proportional to the ratio of polyester with cotton in the blend. Draw frame blending produced better quality yarn as compared to blow room blending, lap former blending and simplex blending.

Keywords: blending techniques; cotton/polyester ratio

INTRODUCTION

The cotton has a loin's share in the economy of Pakistan. It provides raw material for our leading industrial sector. The growing world population needs and ever-changing fashions have changed the consumer trends. Now they demand great versatility, wide variety, higher standards and precision in fabrics, which are scarce in cotton products due to fibre to fibre variation, pest attack and uncontrollable environmental conditions. Therefore, the natural fibres are blended with synthetic fibres, such as cotton with polyester. The ratio of natural and synthetic fibres in the blend is of prime importance due to its multiple uses, economical and environmental conditions. Blending of natural and synthetic fibres is still carried out in sliver form on the draw frame (Klein, 1987). This provides the best blend in the longitudinal direction. Nawaz et al. (1999) reported that there is a gradual decline in yarn strength as the share of polyester fibres decreases in the blend. Li and Van (1990) reported that fibre properties had a significant effect on yarn strength. Anandjiwal and Goswami (1999) investigated that the blending of dissimilar fibres leads to their non-uniform distribution throughout the yarn cross-section, which in turn leads to preferential migration depending on both fibre properties and mechanism of certain spinning processes. The present study was conducted in order to find out the impact of polyester/cotton ratio on the quality characteristics of yarn and also to find out the optimal blending stage that produced excellent quality yarn.

MATERIALS AND METHODS

The present study on the comparison of different blending techniques of cotton and polyester at different stages during fibre to yarn spinning was carried out at the Kohinoor Textile Mills Ltd., Faisalabad and in the Department of Fibre Technology, University of Agriculture, Faisalabad during 1999-2000. Lint cotton samples of MNH-93 were taken from the mills, with

average values of fibre properties as fibre length 27.07 mm, fibre length uniformity ratio 48.58%. fibre bundle strength 90.81 thousand lb/irr', fibre fineness 4.52 ug/in, fibre maturity 82.53% and trash contents! 0.20%, while polyester fibre having the quality characteristics as fibre length 38 mm, fibre denier 1.2, colour/luster semidull, moisture regain 5%, elongation 18.30%, tenacity 7.04 glden and crimps per inch 13. 10, was used in the study.

The blendings of polyester and cotton were carried out in ratios i.e. RI (65:35) and R2 (52:48) at various stages i.e. blow room (TI), lap former (T2), draw frame (T3) and simplex frame (T4). The yarn thus prepared was tested for evaluation of following characteristics:

Tensile Properties of Single Yarn: The tensile properties viz. single yarn strength, elongation and rupture per kilometer, were calculated with Uster Tensorapid. The procedure adopted is that of ASTM Committee (1997). The data were analysed statistically using completely randomised design and Duncan's new multiple range test, as suggested by Steel and Torrie (1984).

RESULTS AND DISCUSSION

Single Yarn Strength: The statistical analysis of single yarn strength at 30' (P/C) blend is shown in Table I(a) which shows that the effect of different blending ratios and blending techniques during fibre to yarn spinning were highly significant, while the interaction between RxT on single yarn strength was non-significant.

The Table I(b) shows that the mean values of single yarn strength for 30' (P/C) yarn were observed as 412.45, 398.61, 422.03 and 387.38 g for TI, T2, T3 and T4 respectively. The best single yarn strength was noted in case of blending technique at draw frame while the lowest value was observed for simplex frame.

For blending ratio, RI (65:35 PlC) produced yarn of the best single yarn strength while the lowest value was in case of R2 (52:48 PlC) yarn. The results showed that more the percentage of polyester fibres, more would be the single yam strength and vice versa. Similar views were expressed by Nawaz et al. (1999) who reported a gradual decline in yam strength due to a reduction in polyester fibres in the blend.

Booth (1983) reported that several factors tended to influence the single yarn strength. He further reported that fineness of fibre affected several properties of the yarn and therefore, influenced the behaviour and properties of resultant yarn and fabrics. Hamid (1987) noted that the single yarn strength gradually diminished with a progressive increase in yarn number.

Yarn Elongation: The statistical analysis of yam

elongation at 30' (PlC) blend is shown in Table l(a) which showed that the effect of different blending ratios and blending techniques during fibre to yam spinning was highly significant while the RxT interaction on yam elongation value was significant.

The Table I(b) shows that the mean values of yam elongation for 30' (PlC) yam were observed as 8.04, 7.87, 8.08 and 7.71% for rt, T2, T3 and T4 respectively. The best yarn elongation was noted in case of blending at draw frame while the lowest value was observed for simplex frame. These findings were identical to those of Klien (1987) who found that blending of natural and synthetic fibres is still carried out in sliver form on the draw frame . This provides the best blend in the longitudinal direction. Regarding blending ratios, RI (65:35 PlC) produced yarn of best elongation while the lowest was obtained in case of R2 (52:48 PlC). These, results showed that the higher the percentage of polyester fibres, more would be the yarn elongation and vice versa. Elongation is a key factor (Sheikh, 1991). He further opined that the yarn elasticity and elongation were also very important in yarn spinning processes. Yarn with low elasticity i.e. Iow elongation tended to break more frequently in weaving. However, Zhu and Ethridge (1997) claimed that increase in elongation would reduce the hairiness of yarn.

Rupture per Kilometer of Yarn: The statistical analysis of rupture per kilometer at 30' (PlC) blend is shown in Table I(a) which indicates that the effect of different blending ratios and blending techniques during fibre to yarn spinning was highly significant while the RxT interaction on rupture per kilometer of yarn was non­significant.

Table I(b) shows that the mean values of rupture per kilometer for 30' (PlC) yarn were observed as 21.07, 20.48, 21.52 and 20.01 gltex for TI, T2, T3 and T4 respectively. The best rupture per kilometer of yarn was noted in case of blending technique at draw frame, while the lowest value was observed for simplex frame. These findings were similar to those of Klein (1987) who found that with evidently different raw materials (e.g. blends of natural and synthetic fibres), the blending at blow room was often unsatisfactory owing to uncontrolled extraction of flocks and the danger of subsequent de-blending.

As to the blending ratio, RI (65:35 PlC) produced yam of the best rupture per kilometer while the lowest was in case of R2 (52:48 PlC) yarn. The results showed that higher the percentage of polyester fibres, the more would be the rupture per kilometer of yam and vice versa. The properties of raw material seemed to directly influence the yam properties as reported by Li and Yan (1990) who remarked that fibre properties had a significant effect on yarn strength. However, Anandjiwal and Goswami (1999) investigated the blending of dissimilar fibres, leading to their disuniform distribution throughout the yam cross-section, which in turn led to preferential migration depending on both fibre properties and mechanism of certain spinning processes.

Conclusion: The study reveals that the quality characters such as single yarn strength, yarn elongation and rupture per kilometer of yarn were directly proportional to the ratio of polyester with cotton in the blend. However, draw frame blending produced better quality yarn as compared to blow room blending, lap former blending and simplex blending.

 

Shahid Saleem Shadl, Asim Mumtaz1 &. Iqbal Javed2
Departments of Fibre Technology' and Math. & Stat.", University of Agriculture, Faislabad
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Fiber (Fibre) Processing

Cotton fiber quality determines the type of yarn and fabric that can be produced. Parameters such as fiber length, strength, and micronaire can be

measured precisely and accurately with high volume instruments (HVI). These instruments, as well as the operating procedures associated with them, are well described and standardized. HVI data are used all over the world by the textile industry in buying

cotton and in managing the mixes in the textile mills. Important, though not yet completely standardized, are measurement, characterization, and quality control standards for lint contaminants. In this chapter, we focus on one specific type of contaminant, cotton lint stickiness.

Effect of Stickiness on Productivity and Yarn Quality

Cotton stickiness caused by excess sugars on the lint, from the plant itself or from insects, is a very serious problem for the textile industry—cotton growers, ginners, and spinners (Hequet et al. 2000, Watson 2000). During the transformation process from fiber to yarn of sticky cottons—opening, carding, drawing, roving, and spinning—the machinery is contaminated to different degrees depending on the processes involved and the location within the machines. This affects processing efficiency as well as the quality of the products.

Stickiness is caused primarily by sugar deposits produced either by the cotton plant itself (physiological sugars) or feeding insects (entomological sugars) (Hendrix et al. 1995). Insects have been documented

as the most common source of contamination in some studies (Sisman and Schenek 1984). The analysis of honeydew from cotton aphids (Aphis gossypii Glover) and sweetpotato whiteflies (Bemisia tabaci (Gennadius) strain B (= Bemisia argentifolii Bellows and Perring)) has shown that aphid honeydew contains around

38.3 percent melezitose plus 1.1 percent trehalulose, while whitefly honeydew contains 43.8 percent trehalulose plus 16.8 percent melezitose under the conditions described by Hendrix et al. (1992). Relative percentages may differ depending on environmental

or feeding conditions. Sucrose is virtually the only sugar in the phloem sap of cotton plants (Hendrix et al. 1992). The insects produce trehalulose and melezitose by isomerization and polymerization of sucrose. Neither of these sugars is produced by the cotton plant (Hendrix 1999); therefore, their presence on cotton lint demonstrates honeydew contamination. Furthermore, Miller et al. (1994) demonstrated that stickiness is related to the type of sugars present on the lint. The authors showed that trehalulose and sucrose, both disaccharides, were the stickiest sugars when added to clean cotton while melezitose (trisaccharide), glucose, and fructose (both monosaccharides) were relatively nonsticky.

Investigations have been conducted to elucidate the factors affecting the behavior of cotton contaminated with stickiness. In textile mills, the method mainly used to reduce the effects of stickiness is blending sticky cotton with nonsticky cotton (Perkins 1984, Hequet et al. 2000).

Gutknecht et al. (1986) reported that stickiness caused by honeydew depends on the relative humidity in which the contaminated cotton is processed. Relative humidity is a function of both water content and temperature of the air. Frydrych et al. (1993) reported that stickiness measured with the thermodetector is dependent on relative humidity. Price (1988) noticed that sticky cotton (with 1.2 percent reducing sugar content) when stored in high relative humidity (70

°F, 80 percent relative humidity) gave more problems during processing than the same sticky cotton stored at low relative humidity (75 °F, 55 percent relative

humidity). However, at low relative humidity the fibers are more rigid, which will increase the friction forces creating static electricity (Morton and Heade 1993). Therefore, milling machinery will require more energy to draw the lint.

Stickiness has also been reported to cause a buildup of residues on the textile machinery, which may result in irregularities or excessive yarn breakage (Hector and Hodkinson 1989). When processing low to moderately contaminated cotton blends, residues will slowly build up. This translates into a decrease in productivity and quality forcing the spinner to increase the cleaning schedule.

Perkins (1983) reported that the cause of the severe stickiness of some 1977 California San Joaquin Valley cottons was probably whitefly honeydew. The

stickiness was most severe in the picking, carding, and roving processes, with frequent interruptions in

production at carding and roving because of ends down and roll lapping. Storage of the cotton for more than 8 months did not relieve the stickiness. Processing the cotton through a tandem card eliminated the sticking problem at carding, but did not relieve the problem at roving enough to prevent production failures.

Fonteneau-Tamine et al. (2001a), studying 26 bales of Sudanese sticky cotton, reported that textile machinery performances decreased when sticky cottons were processed. At more than 50 sticky spots detected with the high speed stickiness detector (H2SD) and relative humidity between 45 and 50 percent during opening and carding, carding is not possible. In addition, stickiness reduces significantly the productivity well below the 50-H2SD-spot limit. As shown in table 1, the roving frame appeared to be the most sensitive

of all the machineries involved in the fiber-to-yarn transformation.

Fonteneau-Tamine et al. (2001b) reported on the same lot of Sudanese cottons that cotton stickiness not only affects productivity but also the quality of the end products. Although a clear decrease in productivity was noted for both the carding and draw-frame operations, it did not translate into a measurable decrease in sliver quality. It is only from the roving frame onward that there is a stickiness-induced decrease in regularity. The coeffient of variation (as a percentage: CV%) of the roving mass is slightly higher, thus increasing the irregularity of the yarn on the ring spinning frame. When considering actual spinning, the quality of ring-spun yarn is more susceptible to stickiness than that of rotor-spun yarn. As shown in the table 2, the regularity. imperfections, and tensile properties clearly highlight this difference between the two processes. The CV% of mass, number of thin places, number of thick places, and number of neps in the ring-spun yarn increases significantly with the number of H2SD sticky points. The tensile properties of the ring-spun yarn decrease

as stickiness increases. By contrast, most of the quality characteristics of the rotor spun yarn are unaffected by cotton stickiness.

Hequet et al. (2000) obtained very similar results. They examined the threshold level of stickiness for acceptable performances of both ring and rotor

spinning, in terms of productivity and quality of the yarn produced. In the short term, between 0 and 11 sticky spots (average H2SD count of sticky spot in the

cotton mixes) the stickiness contamination does not appear to influence the productivity for either ring- or rotor-spun yarns, but it clearly does above this 11-spot threshold. Nevertheless, a slight but significant negative effect on the ring-spun yarn quality has been detected even at the very low levels of stickiness tested. No negative effect has been noticed on the quality of the rotor-spun yarn. In the long term, however, it appears that some insect sugars are slowly contaminating the equipment. This accumulation of sugars may reduce both productivity and yarn quality in the long term.

Stickiness may cause a buildup of residues on the textile machinery, which may result in irregularities or excessive yarn breakage. When the cotton is very sticky it cannot be processed through the card;

however, with low to moderate stickiness levels, yarn can generally be produced. Hequet and Abidi (2002) studied the origin of the residues collected on the textile equipment after processing of sticky cotton blends with low to moderate levels of contamination. They worked with mixes having a very moderate level of stickiness in order to see, over time, a slow residue buildup on the textile equipment. This way of doing

the spinning test is more representative of the industrial practice. Indeed, a spinner will not run a very, or even moderately, sticky blend. He will rather mix the sticky cotton in such a way that no short-term effect will be noticed. Nevertheless, in the long term, residues build up and translate into a slow decrease in productivity and quality, forcing the spinner to increase the cleaning schedule.

Twelve commercial bales contaminated with insect honeydew were selected based on their insect sugar (trehalulose and melezitose) content and their stickiness as measured with the high speed stickiness detector. In addition, five nonsticky bales from one module were purchased for mixing with the contaminated cotton so that alternative stickiness levels in the mixes could be obtained.

Preliminary tests were run on ring spinning before testing the mixes. Thirty pounds of lint from each bale was carded and drawn. If noticeable problems occurred at the draw frame, the process was stopped. If not, the drawing slivers were transformed into roving. If noticeable problems occurred at the roving frame, the process was stopped. If not, the roving was transformed into yarn at the ring-spinning frame. If noticeable problems occurred at the ring-spinning frame, the process was stopped. If not, 100 pounds of

lint was processed for the large-scale test. If noticeable problems occurred at any step of the process, the cotton was mixed with 50 percent nonsticky cotton and the process was repeated. Using this procedure led to the execution of 17 large-scale tests.

High performance liquid chromatography (HPLC) tests were then performed on card slivers, flat wastes, draw frame residues, and the sticky deposits collected at the end of each test on the rotor-spinning and ring-spinning frames. These tests quantify the amount of each sugar, expressed as a percentage of total sugars present. In addition, H2SD measurements were made on card slivers.

After each spinning test was completed, the opening line and the card were purged by processing a noncontaminated cotton, then all the equipment was washed with wet fabrics and thoroughly dried.

From the 12 contaminated and the 5 nonsticky bales, 17 mixes were evaluated in both ring and open-end spinning. As expected, H2SD readings on the mixes

indicated slight to moderate stickiness (from 2.0 to 15.7 sticky spots). During the processing of the 17 mixes, sticky deposits were noticed on the textile equipment as shown in figures 1 to 3.

Figure 4 shows average HPLC results obtained on the 17 mixes for the fiber, the flat waste, and the residues collected on the draw frame and the drawing zone of the ring spinning frame. In this chart the HPLC results are normalized, the base being the HPLC results on the fiber. It shows that trehalulose content is always higher in the residues collected than on the original fiber while the other sugars are not. The same behavior was

observed in rotor spinning (figure 5). Among the sugars identified in contaminated cotton, only trehalulose exhibits higher concentration in the residues.

Figures 6-10 show the nonlinear relationship between trehalulose on the fibers and trehalulose on the residues for some selected locations on the textile equipment. These figures show that during the processing of the mixes having trehalulose content above 5 percent of the total sugars, trehalulose content has a clear tendency

to increase in the residues collected. Consequently, the authors decided to investigate the sugars' properties in order to understand why trehalulose content increases in the residues while the other sugars do not. The

thermal properties of the five sugars identified on the contaminated fiber and on the residues collected on

the textile equipment were investigated. Differential scanning calorimetry was chosen to study the thermal properties of the following dehydrated sugars: fructose, glucose, trehalulose, sucrose, and melezitose. The differential scanning calorimetry profiles were recorded between 25 °C and 250 °C. Among the selected sugars, trehalulose has the lowest melting point (48 °C), as shown in table 3. It begins to melt immediately when the temperature starts rising. The other sugars remain stable when the temperature rises until it reaches 116 °C (melting point of fructose). Therefore, any increase in the temperature of the textile processing equipment will first affect trehalulose, causing it to either stick on the mechanical parts or become the precursor of nep formation. Figure 11 shows one example of a sticky nep collected from the yarn produced in this study.

Sugars belong to the carbohydrate class. They are hydrophilic because of several hydroxyl groups (—OH), which interact with water molecules, allowing many hydrogen bonds to be established. Therefore, several authors (Gutknecht et al. 1986, Price 1988, Frydrych et al. 1993) investigated the relationship between stickiness and relative humidity. It was generally reported that contaminated cottons are less sticky at low relative humidity than at high relative humidity. Therefore, the hygroscopic properties of the five sugars identified on the contaminated fiber were investigated. The quantity of water adsorbed

on each sugar was evaluated at 65±2 percent relative humidity and 21±1 °C. Figure 12 shows the percentage weight gain during the first 12 hours of hydration.

No sugar exhibited any significant variation within this time period except trehalulose, which picks up about 12 percent moisture; this corresponds to two molecules of water per molecule of trehalulose. Then, the weight gain of the sugar samples continued to be recorded until the plateaus were reached. Trehalulose continued to pick up moisture, while fructose began to pick up moisture after 12 hours of exposure to the

laboratory conditions (figure 13). The hydration kinetic was very fast for trehalulose, with the equilibrium being reached after 80 hours, but slow for fructose, with the plateau being reached only after 500 hours. The total amount of weight gain corresponds to three molecules of water per molecule of trehalulose and three molecules of water per molecule of fructose.

If we assume that trehalulose accumulates more on the spinning equipment than other sugars because of its hygroscopicity, then fructose should accumulate in a similar way, but this is not the case. Indeed, the

HPLC tests performed on the residues collected on the

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Figure 5. High performance liquid chromatography results on the 17 mixes for fiber, flat waste, and residues collected on the draw frame and the rotor spinning frame. The HPLC averages are normalized, the base being the results on the fiber. A: card flat; B: draw frame, drafting zone; I: rotor spinning frame, face plate; J: rotor spinning frame, feed table; K: rotor spinning frame, rotor groove; L: rotor spinning frame, rotor housing; M: rotor spinning frame, rotor ledge; N: dust test (Hequet and Abidi 2002).

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Figure 6. Relationship between the trehalulose content on the fiber of the 17 mixes and the trehalulose content on the residues collected from the front rubber rolls of the ring spinning frame. The trehalulose content is expressed as a percentage of the total sugars (y = 14.62Ln(x) — 2.47; R2 = 0.702). The straight line is the equality line (Hequet and Abidi 2002).

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textile equipment do not show any increase in fructose content, even if fructose content was high on some mixes. On the 17 mixes tested, the fructose content, expressed as a percentage of the fiber weight, ranges from 0.012 to 0.101 percent, which corresponds to 10.6 to 33.6 percent when expressed in percentage

of the total sugars identified. Thus, the fact that trehalulose is highly hygroscopic does not alone explain why this sugar has the tendency to accumulate more on the textile equipment than other sugars. The combination of high hygroscopicity and low melting point of trehalulose renders it stickier than the other sugars, allowing its higher concentration on the textile equipment.

The combination of high hygroscopicity and low melting point could explain the higher concentration of trehalulose in the residues collected on the textile equipment than on the original fiber. This research demonstrated that, among the sugars involved in cotton stickiness, trehalulose was probably the cause of the worst problems in processing. Thus, the effect of trehalulose throughout the spinning process was investigated for both conventional and compact ring spinning.

Hequet and Abidi (in press) processed 12 mixes, obtained by mixing sticky cotton with nonsticky cottons, through a short-staple spinning line. In addition to the trehalulose content (determined by HPLC), H2SD readings were obtained. The twelve mixes ranged from 0.013 percent to 0.204 percent of the fiber weight in trehalulose content and from 2.5 to 26.4 H2SD sticky spots. Among the mixes, some had high H2SD readings and low trehalulose content while others had high H2SD readings and high trehalulose content.

For this set of cottons, there was no correlation between H2SD readings and trehalulose content. Previous work done on 150 bales showed the same lack of correlation, especially in the low-to-moderate H2SD stickiness range. There was a marked evolution of the H2SD readings along the processing line and a strong interaction with the type of contaminant (aphid honeydew vs. sweetpotato whitefly honeydew), while there was only a slight evolution of the trehalulose content. It seems that some sticky spots, depending on the sugar composition, are broken into smaller particles in the opening line.

The mixes with high H2SD readings and low trehalulose content (aphid honeydew contamination) had no more ends down than mixes with low H2SD readings. Mixes with high H2SD readings and high trehalulose content (whitefly honeydew contamination) had excessive ends down or could not be processed. Cotton stickiness had a significant detrimental effect on both yarn evenness and yarn hairiness, even for the moderate levels of stickiness tested, but had no effect on yarn tenacity and CSP (count strength product).

In conclusion, stickiness affects productivity of the ring and rotor spinning processes and yarn quality. The origin of the honeydew contamination seems to affect the processability of sticky cottons. For a

given level of stickiness, as measured by the H2SD, cottons contaminated with whitefly honeydew are more problematic to run in the spinning mill than cottons contaminated with aphid honeydew.

Effect of Storage on Stickiness

Storage of cotton has been reported to either reduce or remove the incidence of stickiness. In other instances authors reported little to no effect of cotton storage

on stickiness. Perkins (1986) reported that whitefly honeydew contaminated cotton samples were still sticky after 2 years of storage, while other sticky cotton samples with high physiological sugar contents were much less sticky after only 4 months of storage. Frydrych et al. (1993) reported that some spinners store sticky cottons with the hope that the natural decomposition of the sugars present on the lint will reduce stickiness. The authors concluded that, on the range of cottons contaminated with insect honeydew tested and after storage for more than 2 years under various relative humidity and temperature conditions, there was no significant change in cotton stickiness measured using the thermodetector.

It seems that stickiness from high level of physiological sugars may disappear after several months of storage because of biotic activities on the lint, while stickiness from insect honeydew will not. This could be due to the inability of most of the microorganisms to metabolize some insect sugars.

Effect of Mill Conditions

In past publications, it has been suggested that
machinery speeds, settings, roll pressures, and

humidity levels are likely to influence processing problems, namely roll lapping, caused by sticky cotton. In fact, many have provided data that show dry (low-humidity) conditions in processing areas of a textile mill will allow for the adequate processing of sticky contaminated cottons (Reynolds et. al. 1983,

Perkins 1983, Gutknecht 1988, Price 1988). However, Backe (1996a) has suggested that (in addition to low humidity) bale bloom time, crush roll pressure, waste extraction, and cleaning cycles, either by themselves or in combination, can aid in alleviating the processing problems associated with sticky cotton.

Gutknecht (1988) has shown that the potential for stickiness increases for sticky contaminated cotton as the relative humidity of the surrounding atmosphere increases. Chellamani and Kanthimathinathan (1997) have reported that processing cottons known to be contaminated with stickiness at a relative humidity of 50 percent or lower will reduce the processing

problems associated with these cottons. Backe (1996a) states that a relative humidity of less than 42 percent in the blowroom, carding, and drawing processes was helpful in processing sticky cotton. In addition, he indicates that success was met by allowing the bales to bloom in a fairly dry atmosphere for 48 hours prior to processing. Bringing the humidity surrounding

the sticky contaminated cotton during processing to low levels dehydrates the sugars present on the sticky contaminated cottons. Hughes et. al. (1994)

demonstrated that dehydrating the cotton to low levels of moisture drives off water until the sugar of the sticky contamination changes to a crystalline structure, which is not sticky. These researchers suggest that this effect seems to occur somewhere between 4.5 and 5.0 percent moisture content.

In processing sticky cotton, it was suggested by Backe (1996a) that relieving the crush roll pressure at the card will help in reducing the roll lapping on the crush rolls. However, Perkins (1993) warned that

removing the crush roll pressure or increasing the gap between the crush rolls will allow large trash particles to remain in the stock, which could adversely affect yarn quality. Further, removing crush roll pressure

to alleviate carding difficulties with sticky cotton will only act to transfer the problem downstream to drawing, roving, combing, and spinning. At these

processes, roll lapping is a result of the sticky point on the cotton fiber attaching to the rollers in the drafting zone and subsequently collecting fiber passing through the zone. Known methods of minimizing this effect

are increasing the cleaning cycle of drafting rolls or treating the rolls with iodine to coat the rolls. Coating the rolls with iodine keeps the sticky point from adhering to the rollers and creating a roll lap (R. Insley, 2001, personal communication).

Use of Additives

Since the 1980's, there have been many reports on the use of additives to process sticky cotton. Some

success was demonstrated with nonionic combinations of hydrocarbon plus surfactant (Perkins 1983, 1984). However, Perkins (1971) warns that cationic additives will not be completely removed downstream in textile processing and will result in reduced scouring and dyeing efficiency. Chun and Brushwood (1998) have shown that treating cotton with water plus ammonia or urea at a 30 percent moisture content during storage for 15 days drastically reduced sugar content and stickiness without adverse affect on fiber properties. A practical application of these findings has not been developed.

Backe (1996b) reported on the use of a new additive, Gintex, for processing sticky cottons. This product

is a nonoil- and nonsilicon-based product that is said to reduce fiber-to-machine friction so that fiber and foreign matter move freely without static electricity. In 1995, Backe (1996b) reported that several mills used this additive to process sticky cottons from the 1995 West Texas crop, Uzbekistan crop, and the crop from Francophone Africa with good success. Some of the positives of processing with this additive were said to be less dust, improved cleaning efficiency, increased yam tensile properties, and improved mass evenness in addition to alleviating sticky cotton processing difficulties. Typically the additive is applied at the bale feeding (top feeder or hopper) stage of processing at the textile mill. Treating cottons with additives may be

feasible if the user is willing to incur the additional cost for not only the additive but also the hardware to apply it.

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E.F. Hequet, N. Abidi, M.D. Watson, and D.D. McAllister

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Adoption Of Ring Spinning In Lancashire, 1880-1913

TIMOTHY LEUNIG

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This paper returns to the long-running debate concerning the slow adoption of ring spinning in Lancashire. It uses new data on the location of firms within Lancashire to more accurately analyse the causes of Lancashire’s continuing preference for the mule. It shows that the primary determinants of spindle type were not the supply side factors of transport costs and technical inter-relatedness, but instead were demand side factors, notably the high level of demand for fine yarn, and the sizeable yarn export trade. The paper also resolves two smaller puzzles, the atypicality of Oldham’s investment patterns, and Lancashire’s lack of interest in paper tube rings.

The paper proceeds as follows. The first section contains a brief summary of the industry’s rise and fall, along with a survey of the literature on the slow adoption of ring spinning. The next section shows analytically that the standard divide into vertically integrated and vertically specialised firms is insufficient, and instead proposes a three way division into vertically integrated firms, vertically specialised spinners located near to weaving firms, and vertically specialised firms with no weavers close by. Section three confirms empirically that all three types of firm existed in substantial numbers. The fourth section shows that vertically specialised spinners located close to weavers adopted rings as often as vertically integrated firms, and these

groups adopted rings four times as often as vertically specialised firms without weavers close by. This allows us to compare the relative merits of the two supply side factors, transport costs and technical inter-relatedness. The final substantive section demonstrates that the division of the industry proposed in the paper, the size of the sectors, and their propensity to adopt rings are in line with both observed investment behaviour and the total stock of spindles in Lancashire. It shows that although the supply side factors mattered, they were less important than the demand side issues in determining the number of rings and mules in Lancashire.

THE INDUSTRY AND THE LITERATURE

Although Britain grows no cotton, the spinning and weaving of imported raw cotton proved central to Britain’s development as an industrial nation. The rise and decline of the industry is well known, and is summarised in figure 1.

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Cotton’s centrality to British industrialisation is reflected in the literature, with all writers from W.W. Rostow to N.F.R. Crafts and C. Knick Harley perceiving cotton to be the most important element in the British industrialisation process.1 But the decline of cotton has not prompted such unity. In particular there remains a dispute as to whether the Lancashire cotton industry should have behaved differently in the ‘glory years’ prior to 1914. A number of issues have been raised, including the question of technology. Why was Britain so much slower at adopting new technology, such as the ring spindle and automatic (Draper) looms? Was the atomised structure of the industry, with a large number of relatively small, vertically specialised firms, part of the problem?

Before we survey the literature looking at the Lancashire’s slow adoption of ring spinning, it may be helpful to offer a short explanation of cotton processing. The industry has two main sectors, spinning and weaving. The spinning sector transforms raw cotton into yarn or thread, which can then be woven or knitted into cloth, or used for sewing or lace. Yarn is divided into ‘warp’ and ‘weft’ yarns; warp yarns are held in position during weaving, while weft yarns are interlaced between the warp yarns to make cloth. Warp yarns have to be stronger than weft, and are sometimes called twist yarns, reflecting the extra twist inserted during spinning to increase strength .2 Once spun, warp yarns are ‘warped’, that is, rewound onto warping beams, each of which contains many parallel warp yarns. The weaving sector transforms yarn into cloth. A single package of weft yarn is placed in a weaving shuttle; that shuttle is then shot back and forth between the warp threads in order to make cloth. In so doing the weft fills the gaps between the warp yarns, and for that reason is sometimes called filling yarn. When the weaving shuttle runs out of yarn, the loom is stopped and the weaver places a new weft package in the shuttle. This process is manual on a power loom, and automatic on an automatic (Draper) loom. The ratio of warp to weft yarns varies according to the type of cloth: on average coarse cloth had 33 percent

more warp than weft.3 All yarns, warp and weft, are classified by count, which measures the fineness of the yarn. A high number indicates a finer yarn; a yarn of count n has n lengths of 840 yards per pound weight. In Britain counts of up to 40 were classified as coarse, counts of 40-80 as medium, and counts of over 80 as fine.4

Prior to the first world war there were two competing spinning technologies, mule spinning and ring spinning. In Britain mules were used for spinning all counts of yarn, but rings were rarely used for counts of over 40.5 At a technical level the two methods are fundamentally different. The mule spins intermittently, that is to say, it spins approximately five feet of yarn, and then winds that section of yarn onto the spindle before spinning the next five feet of yarn. The ring, in contrast, spins and winds in one action, and is thus able to spin continuously. The ring spindle produces more yarn per hour than the mule,6 but at a cost of treating the raw cotton more harshly, necessitating the use of a better grade of raw material for any given type of yarn. In Lancashire, and elsewhere, mule spindles were operated by relatively highly paid men, and ring spindles by relatively lowly paid women. Both methods produce yarn in relatively small packages, generally around six to eight inches tall, and no more than two inches across. Mule spun yarn can be lifted off of the machine as a package made up of nothing but yarn, whereas ring spun yarn is attached to a wooden bobbin, from which it cannot easily be removed. Mule spun weft yarn could be taken from the spindle and placed directly into a power loom shuttle, whereas ring spun weft yarn had to be rewound prior to weaving. Ring spun yarn was stronger than mule spun yarn, and was a prerequisite for using automatic looms. For these reasons we say that there are technical complementarities between weft mules and power looms, and between rings and automatic looms.7

Many early writers were in no doubt that Lancashire’s failure to adopt rings was a manifestation of ‘the conservatism of our captains of industry who have idolised the obsolescent techniques which have made the fortunes of their grandfathers.’8 Since the publication of Lars Sandberg’s pioneering work in 1969, no one believes that those firms who purchased mules were doing anything other than responding accurately to the costs that they faced. The question becomes whether the cost structure could have been altered so that rings were preferred more often.9

Sandberg argued that the industry was making a smooth transition towards ring spindles for all counts up to around 40, a little higher for warp, a little lower for weft, but that mules continued to be preferred for counts finer than 40s. In this story the continuation of a large mule sector had two causes, demand patterns and factor costs. The demand for supra-40 counts was high by international standards, and British costs were such that mules remained advantageous for those counts. In particular the relative cost of skilled mule labour to that of unskilled ring labour was low in Britain, so Lancashire employed mules for counts spun on rings in New England.

Sandberg also noted a further potential cost of adopting rings: a ring spinner may face higher transport costs. As mentioned, the mule produces packages consisting entirely of yarn, whereas the ring spins its yarn onto a heavy wooden bobbin from which it cannot be removed easily. The

spinner has two options when transporting the yarn. The first is for the bobbin to be transported with the yarn, and later returned for re-use. As the bobbin weighed twice the yarn spun onto it, this would imply a fivefold increase in transport costs.10 The alternative is to rewind the yarn into packages made up entirely of yarn, prior to shipping, but the cost of so doing was as high as the additional transport cost.11 Lancashire’s industrial organisation system, with individual firms either spinning or weaving, made this potentially important. In contrast it did not matter in the U.S. where spinning and weaving were carried out by a single firm, on a single site. Within Lancashire the additional cost was lower for warp yarns, because they had to be rewound onto (relatively light) warping beams between spinning and weaving in any case. Ring spinners could warp their yarns prior to sending, rather than allowing the weaver to do the warping.

As well as the cost differences in labour, raw cotton and transport; Sandberg noted other potential factors influencing technological choice. The difference in capital cost in purchasing rings and mules, and the cost of fuel and lubricants proved small in both Lancashire and New England. 12 Unions were unimportant in Lancashire, and marginal in New England. In both cases male mule spinners were more likely to be unionised than were female ring spinners, but the Lancashire mule spinners’ union was less likely to be obstructive. Finally Sandberg noted the technical complementarity between ring spindles and automatic looms. Since the latter were rare in Britain, Sandberg argued that technological inter-dependence could be ignored. The advantages and disadvantages of rings and mules are summarised in table one.

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Following several empirical corrections to Sandberg’s work, William Lazonick agrees that British managers were responding accurately to the costs that they faced.13 He shows, however, that Sandberg overestimated the labour cost advantage and underestimated the transport cost premium. According to Sandberg the labour cost advantage outweighed the transport cost premium by a factor of five, making transport costs a secondary factor in his analysis.14 In contrast, Lazonick finds that the labour cost saving on rings was less than 25 percent greater than the transport cost premium.15 Given that there was a reasonable chance that the bobbin – an expensive item – would not be returned, Lazonick argues that the savings from using rings were insufficient to lead firms to install them unless the spinner was vertically integrated with the weaver.16 These cost estimates, along with the extensive size of the vertically specialised sector leads him to conclude that ‘The primary constraint on the introduction of ring spinning in Lancashire was the cost of shipping ring yarn.’ 17

Lazonick buttressed his finding that Lancashire’s industrial structure slowed the rate of ring adoption in two ways. First, he argued that not only would vertical integration overcome the transport cost constraint, but was also essential if corporate capitalist firms were to introduce ring spinning and automatic looms in a co-ordinated fashion.18 In this story it is incorrect to dismiss the idea of technological inter-relatedness between ring and automatic loom simply because so few British firms adopted automatic looms prior to the first world war. On the contrary, this fact serves to emphasise the need for co-ordinated technological change in the industry. Lazonick showed that those ring spindles that existed in Britain were concentrated in the vertically integrated sector of the industry,19 especially for weft yarn.20 Observed investment behaviour thus implies that specialised firms faced a constraint not faced by their integrated rivals. Finally,

Lazonick also made use of a detailed case study of one of the Lancashire cotton towns, Oldham. ‘With its standard count of 32, large limited liability companies, and a high growth rate, the Oldham district was very favourable terrain for investment in ring spinning. Yet in the decade prior to World War 1, 75 percent of Oldham’s added capacity took the form of mules.’21 Lazonick argues that Oldham ‘puts the burden of proof on those who reject a “bias in favor of mules” on the part of Lancashire’s cotton mill managers’, 22 although Sandberg held that ‘Oldham was atypical in its response to ring spinning ... its relevance to an industry-wide study is limited.’23

Gary R. Saxonhouse and Gavin Wright use the records that survive for six of the eight textile machinery makers to cast doubt on the link between rings and vertical integration. They note that Japan’s vertically specialised industry used rings, whilst the integrated industries of Russia and Canada continued to make sizeable mule purchases.24 They also note that had Lancashire’s vertically specialised spinners been constrained from adopting rings by the transport costs of moving wooden bobbins, they could have used paper-tube ring machines.25 These machines were manufactured in Lancashire, and enabled the yarn to be spun onto paper tubes instead of wooden bobbins. The very low rate of paper tube adoption leads them to conclude that transport costs cannot have been a constraint for Lancashire cotton spinners. Lazonick notes that Saxonhouse and Wright’s claims for paper tubes do not address the second part of his critique of the industry, that the inter-relatedness between ring and automatic loom implies that these machines will be taken up more readily when investment decisions are co-ordinated.26

Saxonhouse and Wright show that the Indian and Russian industries, which ordered both rings and mules, did not use mules for higher counts than rings. This leads them to argue that ‘the rationalisation of the British preference for mule-spinning in terms of the composition of demand

for British goods is similarly unsustainable.’27 They conclude instead that the main determinant of technological choice at the country level stems from the mules’ more gentle treatment of the raw cotton. Those industries that needed to or chose to economise on cotton, including India, Russia and Lancashire opted for the mule, ‘a machine whose forte was getting the most out of low-quality cotton’,28 while others with plentiful supplies of reasonable cotton, such as Brazil and the US, relied on the ring.

CO-LOCATION: AN ALTERNATIVE WAY TO ELIMINATE
TRANSPORT COSTS

Our re-interpretation of the determinants of technological choice starts from the observation that, excluding paper tubes, to which we return later, there are theoretically three, rather than two, ways in which ring-spinning firms can eliminate the transport cost premium on moving their yarn to the weaver. The first is to rewind the yarn from the bobbin into packages made up entirely of yarn. The literature is unanimous that such rewinding was prohibitively costly. The second, as Lazonick has argued, is for spinning firms to be vertically integrated with weaving firms, so that spinning and weaving are carried out on the same site. The third way, advanced here, is for independent spinners and weavers to be located close together. Avoiding transport costs does not require that the spinner and weaver are co-owned, merely that they are co-located.

It follows that the division of the industry into the vertically integrated and vertically specialised sectors is insufficient. Instead we should sub-divide the vertically specialised sector into two parts: vertically co-located firms, and vertically isolated firms. A vertically co-located spinning firm is defined as one with enough weaving capacity nearby to allow them to be sure that they could sell their yarn to local weavers. Further, that market must be thick enough to avoid hold-up problems: local weavers must not be able to exploit the spinner’s dependence on the local market. In other words the spinner must have both sufficient looms and, independently, those looms must be owned by a sufficient number of weaving firms. In contrast, a vertically isolated firm is defined as one that does not have substantial weaving capacity close by. Note that this

does not imply that the firm is geographically isolated in any absolute sense, simply that it is isolated from firms at next stage in the production process. Indeed, as we shall see, many vertically isolated firms were located in Oldham, a town of many spinners, but few weavers.

Since all firms were located in south-east Lancashire, an area about twenty miles square, we take as given that all three groups of firms faced broadly the same raw materials and labour costs, had the same access to information and were able to purchase new machinery on the same terms. Further, the technical complementarity between weft mules and power looms applied to all

firms. There are, however, two important potential constraints that vary by group. Vertically integrated firms face neither a transport cost constraint nor a problem of introducing rings and automatic looms in a co-ordinated manner. Vertically specialised but co-located firms also escape the problem of transport costs, but do face the co-ordination constraint, while vertically isolated firms face both transport cost and co-ordination constraints. In effect we have three equations and two unknowns. By contrasting the behaviour of integrated and co-located firms we can discover whether co-located firms’ inability simultaneously to introduce rings and automatic looms was a constraint on ring adoption. Similarly, by comparing the rate of ring adoption between vertically co-located and vertically isolated firms, we can test whether transport costs were a constraint. We use constraint to mean a factor that affected ring adoption rates, as opposed to simply being an additional cost that was more than covered by other offsetting cost reductions.

THE EXISTENCE OF CO-LOCATED FIRMS

We begin by demonstrating the existence of the vertically co-located sector. In his original analysis Sandberg assumed that all firms in the Lancashire cotton industry were vertically specialised and vertically isolated, with spinners located 30 miles from weavers. 29 Broadly speaking spinners were to be found in the south, and weavers in the north. Lazonick noted that some Lancashire firms were vertically integrated, but, using the same source, retained the assumption that all vertically specialised spinners were vertically isolated, and located 30 miles

from weavers.30 We use a new source, the British Government’s 1906 Enquiry into Earnings and Hours, to show that of the coarse yarn that was spun and woven into cloth in Lancashire, 33 percent was produced by vertically specialised, co-located spinners. A further 36 percent of yarn came from vertically integrated firms, while only 31 percent had to be drawn from firms that were vertically specialised and geographically isolated.

In 1906 the Board of Trade sent out 2329 detailed earnings and hours schedules to firms in the cotton industry, of which 967,or 41.5 percent, were returned .31 The Board found the sample representative, citing compatibility with the earlier 1904 Factory and Workshop Returns, and concluding that ‘the returns for each of the different industries included may be regarded as covering a sufficiently large proportion of the work people employed to yield sound statistical results.’32 Their report on cotton runs to 324 pages of statistics. For our purposes what is most important is that the regional breakdown of spinners and weavers within Lancashire is accurate. Three pieces of evidence suggest that this criterion is met. First, working from Worrall’s Directory, Mike Williams and D.A. Farnie calculate that the southern (spinning) towns contained 78.5 percent of the industry’s spindles in 1903. Using the 1906 Enquiry, we calculate that these towns contained 81.0 percent of all spindles.33 Again using Worrall’s Directory, Farnie also finds that the weaving district contained 66.4 percent of all looms, while the 1906 Enquiry gives a figure of 64.9 percent.34 In both cases the figures are very close indeed, making it clear that the overall distribution of spindles and looms between spinning and weaving areas is broadly accurate in the 1906 Enquiry. Comparing the 1906 Enquiry figures for Oldham to those provided by Lazonick reinforces this impression of accuracy. Lazonick states that, in 1907, Oldham

accounted for 25 to 30 percent of spinning capacity, contained about 40 percent of Lancashire’s sub-40 mule spindles, well over one-third of Lancashire’s total sub-40 capacity, and that, in the decade prior to 1914, 75 percent of Oldham’s new spindles were mules. According to the 1906 Enquiry the equivalent four figures are 31 percent, 41 percent, 34 percent and 82 percent. 35

Again, in each case the 1906 Enquiry figures are close to those from an independent source. Finally, our confidence is enhanced by the clarity of the results. Those areas found to have sufficient weavers to allow us to define their spinners as co-located do so by a considerable margin. The 1906 Enquiry would need to contain errors of considerable magnitude to reverse the findings. As well as offering a reliable regional breakdown, the 1906 Enquiry has one important advantage over other sources: it distinguishes between coarse, medium and fine spinning. As noted above, rings were only used for coarse yarn in Britain, so we are able to limit our analysis to those spinners who would have been deciding between rings and mules.

The 1906 Enquiry gives job and district specific information on 10,010 mule spinners, 4,001 ring spinners and 72,134 weavers. 36 By converting employment data into output data, we can assess how much yarn was spun and woven in each of twelve districts. The 1906 Enquiry sub-divides weavers in each district by the number of looms tended. This makes it trivially easy to calculate the number of looms of any one area: this measure of weaving capacity is given in table two. 37

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The 1906 Enquiry sub-divides spinners in each district into ring spinners, coarse mule spinners, medium mule spinners and fine mule spinners. Ring and mule spinners tended different numbers of spindles, and each category of spindle had different levels of productivity. We therefore convert first from employment to actual spindle numbers, and then from actual spindle numbers to ‘effective’ spindle numbers, which are corrected for the different level of productivity per spindle. The full details are given in the appendix. Effective spindles are taken as a proxy for output, and reported in table three.

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We now have, by district, the number of effective spindles – a close proxy for yarn output; and the number of looms – a close proxy for weaving capacity. We know that, for Lancashire as a whole, yarn output and weaving capacity must be equal, taking into account that some yarn was exported, and some was not woven but used instead for hosiery, lace and elastic webbing. 38 To allow ready comparison of yarn output and weaving capacity in each area, we multiply the number of looms by the spindle to loom ratio, 72:1. This allows us to express both yarn output and weaving capacity in effective spindle terms. The results are given in table four.

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Notes: Coarse is defined as sub-40 yarns. All figures are in thousand effective spindles,

figures do not sum owing to rounding. For division between integrated and co-located firms, see text.

Sources: Cols 2 & 3: table 2; col. 4: table 1; col. 5 is the minimum of col. 2 and col. 3.

Those districts where weaving capacity exceeded total spinning output are termed ‘co-located’ districts: all coarse spinners in these areas could have sold all of their yarn to weavers in their districts. Given that weaving firms were on average 30 percent smaller than spinning firms, there would also have been sufficient weaving firms to prevent spinners being faced with hold-up problems.39 Although it is straightforward to classify all spinners in these districts as co-located, it does not follow that all spinners in all other areas were vertically isolated. Some areas, such as Ashton and Stockport had sizeable weaving sectors in absolute terms, while others, such as Manchester, were close to being self sufficient in weaving. In these areas many coarse spinners could have been confident that they could have their yarn woven locally. The one exception that stands out is Oldham, where spinning output exceeded weaving capacity by a factor of 23:1. Oldham spinners were indeed vertically isolated.

Of course, the overall figure for yarn that could be woven locally includes yarn that was spun and woven by integrated firms. We know that integrated firms accounted for 23.6 percent of industry output in 1907, and that they were concentrated in the coarse goods sector. 40 We therefore assume that 80 percent of their output – rather than the 60 percent figure for the industry as a whole – was coarse. This implies that the yarn that could be woven locally was made up of 4.1m spindles-worth of yarn from vertically integrated firms, with the remainder, 3.7m spindles-worth of yarn, being produced by vertically specialised, co-located firms. This gives three sectors broadly equal in size, with integrated firms accounting for 36 percent, co-located firms for 33 percent and isolated firms for 31 percent of coarse yarn production.

Since we define a vertically co-located district as one in which spinners did not face a transport cost constraint, we need to show that weaving firms in such districts were located in the immediate vicinity of spinners, rather than simply in the same district. An unpublished thesis by James Cotton on the town of Blackburn allows us to do this. Cotton lists 132 mills in operation in Blackburn in 1919, stating whether they were vertically specialised spinners, weavers or integrated spinner-weavers at that date. Of these, he is able to exactly locate 118 of these mills: 8 spinners, 104 weavers and 6 integrated firms. He plots these on a large-scale map (six inches to one mile), from which we can measure precisely the distance between spinning and weaving mills.

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As table five shows, every vertically specialised spinning firm in Blackburn had more than 20 weaving mills within half a mile. We are correspondingly confident that these spinners are correctly characterised as co-located.41 Although we do not have evidence of this calibre for other towns, Cotton demonstrates that proximity to canals, rivers and major roads explains three quarters of mill locations in Blackburn.42 This strongly suggests that that clustering pattern of mills in Blackburn will be replicated in other cotton towns.

INVESTMENT BEHAVIOUR BY FIRM TYPE: WHAT CONSTRAINED
RING ADOPTION?

Having established the existence of three sectors, we now test whether the sectors differed in their rates of ring adoption. We do this by comparing how frequently firms in each group chose rings over mules between 1880 and 1906/7. 1880 is the year in which the ring first became available, 1906/7 are chosen for data availability. Since all rings in place in 1906/7 were installed

after 1880, comparing the stock of rings in 1906/7 with total spindle purchases between 1880 and 1906/7 tells us how often manufacturers picked rings over mules. Spindle purchases can be divided into two types: additional spindles for new mills and extensions, and replacement spindles. The number of additional spindles is the change in sector size between 1880 and 1906. The number of replacement spindles is a little harder to assess. We know that ‘English mules were built to last’ ,43 and needed replacing only after fifty years.44 This means that mules installed between 1830 and 1856 would have needed replacing between 1880 and 1906. Since the automatic mule was introduced in 1830 all mules in place in 1856 must have been installed between 1830 and 1856, and would have needed replacing between 1880 and 1906. We therefore use the stock of spindles in 1856 as our estimate of the number of spindles replaced between 1880 and 1906.

The behaviour of integrated firms has been extensively studied, and the necessary data is readily available. Farnie uses the Returns of the Factory Inspectors to calculate the number of spindles in integrated firms in both 1856 and 1880.45 Work by Sandberg on the Census of Production and by Lazonick on Worrall’s Directory give the number of rings and mules in integrated firms in 1907.46 This gives us sufficient information to assess the frequency with which integrated firms picked rings over mules.

Although data that explicitly distinguishes between firms that are vertically specialised but co-located and those that are both vertically specialised and isolated is not generally available, town specific data is reasonably available, at least for the post 1880 period. We now know that spinners in Oldham can be characterised as vertically isolated – only 4 percent of their yarn could have been woven locally – so we use the behaviour of Oldham spinners to assess the behaviour of vertically isolated firms. Similarly, we know that all spinners in the northern towns of Accrington, Blackburn, Burnley, Preston and Rochdale were all able to have their yarn woven

locally, so we use data for these towns to measure the behaviour of vertically co-located firms.47 Data on the number of spindles in 1880 and 1906 are taken from Farnie’s work; the proportion that were rings in 1906 is given by the 1906 Enquiry.48 We do not have town specific data prior to 1880, so we assume Farnie’s Lancashire wide figure for the proportion of spindles in all specialised firms in 1880 that were installed prior to 1856 holds for firms in both areas.49

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Notes: Co-located districts comprise the Accrington, Blackburn, Burnley, Rochdale and

Preston 1906 Enquiry districts. Figures do not sum owing to rounding.

Sources:

Rows 2 & 3: Integrated firms: 1906: Sandberg, “American Rings,” p. 29, Lazonick “Rings and Mules,” p. 394; 1880: Farnie, English Cotton Industry, p. 317; Co-located districts: Williams and Farnie, Cotton Mills, p. 46; Oldham: Farnie “Emergence,” p. 42. Aggregate spindle numbers are converted to m.e.s. using the ring to mule ratios in table 2.

Row 4: Row 2 minus row 3

Row 5: Farnie, English Cotton Industry, p. 317.

Row 6: Row 4 plus row 5

Row 7: Integrated firms: In the absence of data, we note the standard view that integrated

firms were more heavily concentrated in the coarser section, and assume that 80 percent of m.e.s. were devoted to sub-40 production. Co-located districts and Oldham: table 2.

Row 8: Integrated firms: Sandberg, “American Rings,” p. 29, Lazonick “Rings and

Mules,” p. 394; Co-located districts and Oldham firms, table 2.

Row 9: Row 7 minus row 8

The result from table six is unambiguous: rings were the clear majority choice for both vertically integrated and co-located firms, whereas mules were the clear majority choice for vertically isolated firms. We must note one reservation. The data for ‘firms in co-located districts’ and ‘Oldham’ cover all firms, that is, vertically integrated as well as vertically specialised firms. Since there was little weaving capacity in Oldham the data cannot contain many integrated firms, so the figure is a reliable indicator of the choices of vertically specialised firms in Oldham. In contrast we estimated earlier that just over half of the effective spindles in co-located areas were in fact in integrated firms, adding a strong converging bias to our result. That said, as the results for integrated firms and co-located district firms are close, it follows that vertically specialised co-located firms were choosing rings over mules about as often as were vertically integrated firms.50 Notwithstanding the limitations of the data, the overall result that the choices of co-located firms were similar to those of integrated firms, and substantially different to those of isolated firms seems to be established by a sufficient margin to be considered sound.

We now know which constraints were binding. We noted that vertically isolated firms faced transport costs that was not faced by vertically co-located firms. As vertically isolated firms were only one quarter as likely to pick rings as were vertically co-located firms, we can conclude that Lazonick is right that transport costs did act as a constraint on the adoption of ring spinning. It is worth noting, however, that this constraint, far from affecting all vertically specialised firms, only affected those specialised firms located in areas with few weavers close by. Proving both the existence and limited nature of this constraint allows us to resolve Sandberg and Lazonick’s disagreement over Oldham. Lazonick is right to argue that transport costs did constrain the

adoption of ring spinning in Oldham. But as this paper shows, Oldham was almost unique within Lancashire in having such a high ratio of yarn output to weaving capacity. Lazonick is not right, therefore, to think that ‘the Oldham district was very favorable terrain for investment in ring spinning’51, instead Sandberg was correct to argue that ‘Oldham was atypical in its response to ring spinning ... its relevance to an industry-wide study is limited.’52

We also noted that the difference between integrated and vertically co-located firms was that the former were able to introduce rings and automatic looms in a co-ordinated manner whereas the latter were not. We found the investment behaviour of the two groups to be similar, so we know that vertical specialisation was not per se an obstacle to ring adoption. Vertically specialised firms’ inability to co-ordinate the introduction of these two machines did not retard the adoption of ring spinning. This result should be unsurprising: automatic looms were the exception even in integrated firms.53

The finding that integrated and co-located firms had similar ring adoption rates throws doubt on Lazonick’s claim that rings were used for weft in integrated but not specialised mills. 54 If both groups had the same rate of ring adoption, it seems likely that either both or neither group used rings for weft. In fact the technical complementarity between mules and power looms seems to have been such that neither group used rings for weft to any extent. Instead, firms in both groups shifted well-functioning warp mules over to the production of weft yarn, and used new ring spindles to produce warp yarn. Three pieces of evidence support this claim. First, both integrated and co-located firms had more mules than rings in total, making it possible that rings were limited to one side of the production process. Second, and more importantly, both groups continued to purchase new mule spindles. Nor were their purchases trivial: table six shows that the two groups purchased 1.8 and 1.1 million coarse mule spindles in the quarter century after

the ring’s introduction. This indicates that they perceived mule spindles to have a clear continuing role in the production process.

Third, Worrall’s Directory provides direct evidence that integrated firms rarely used rings to produce weft prior to the invention of the automatic loom.55 Worrall lists 272 integrated firms, with 188 firms specifying spindle type. Of these 188, 13 used only rings, 86 used only mules and 89 used both types. This does not mean that 13 firms used rings for weft, because many integrated firms produced only part of their yarn, purchasing the remainder in the market.56 Of the 13 ring only firms, four state explicitly that they produced only warp yarn, presumably purchasing weft from outside suppliers, while four state that their rings were used for warp and weft, and five give no details. Of these five, three have low spindle to loom ratios similar to those firms known to purchase weft yarn, while two have high spindle to loom ratios, suggesting that they were producing their own weft yarn.57 Our best guess, therefore, is that six of the 188 integrated firms used only rings for weft.

In addition, some firms using both rings and mules may have used rings for weft as well as warp. Without knowing the warp to weft ratio of each firm’s cloth, we cannot be certain. We can say, however, that if British cloth output had the same distribution of warp to weft ratios as the 677 coarse cloths sampled by the US Tariff Board, then the distribution of rings to mules in the Worrall sample would imply that ten integrated firms used both rings and mules to produce

weft.58

It appears, therefore, that rings were used for weft by no more than 10 percent of the 188 integrated firms whose machinery choices are recorded. This figure overstates the percentage of weft that was spun on rings, as the majority of these firms were using both mules and rings for weft production. Since integrated firms account for under a quarter of the total industry,59 and that we know that rings for weft were very much the exception in vertically specialised firms, it seems unlikely that more than 2 percent of Lancashire’s total weft was spun on rings. The cost of rewinding ring weft yarn into shuttle ready packages – a stage not necessary when using mules – appears to have been sufficiently high that the use of weft rings and power looms was exceptional, whether or not the firm was integrated. Since even integrated firms adopted automatic looms only very slowly, the use of rings for weft was, if not unheard of, at least unusual in this period.

This finding would explain the relatively sparse references to ring weft in standard contemporary texts. Sandberg laments that James Winterbottom, writing in 1907, ‘neglected to include ring weft’, in his discussion of the suitable raw cotton lengths for differing counts of yarn. 60 Winterbottom’s ‘neglect’ is much easier to comprehend if rings for weft were an unusual choice. Similarly J.E. Holme, writing in 1887, states that ‘the ring has made great progress in the cotton industry for warp yarns; but it has not yet brought any great advantage for weft yarns.’61 Even as late as 1921 William Taggart argued that ‘Weft yarns are not so easily produced on the ring system as on the mule.’62 Like Winterbottom, he gives details of suitable twist factors for mule warp, mule weft and ring warp, but not for ring weft .63

The finding that rings for weft were exceptional even for integrated firms allows us to better understand the sense in which transport costs acted as a constraint on vertically isolated firms in Oldham. It is clear that the issue is not, after all, the transport of ring weft on heavy wooden bobbins: even integrated firms did not use rings for weft. The difference between ring usage in

integrated and co-located firms on the one hand, and vertically isolated firms on the other, relates to the spinning of warp yarns, not weft yarns. Ring warp yarns did not, of course, have to be shipped on heavy wooden bobbins, as the spinner could warp the yarn prior to sending it to the weaver. Warping beams were not, however, weightless. A standard 36-inch warping beam weighed in the region of 30 to 521/2 pounds in 1900.64 That beam would have held between 91 and 248 pounds of yarn, depending on the type of cloth to be made.65 Given that the beam had to be returned, the transport cost of shipping ring warp on a beam would exceed that of shipping mule warp in yarn packages by between 24 and 115 percent, depending on the exact weight of the beam and the fineness of the yarn. These figures are dramatically smaller than the five-fold increase in transport costs for ring weft. That a smaller increase in transport costs should act as a constraint on ring adoption fits well with the conclusions from Saxonhouse and Wright’s machinery data, namely that the choice between rings and mules was much more finely balanced than had previously been realised.66 In that context a much smaller transport cost increment would be sufficient to reduce the take-up of ring spinning. The finding that ring warp but not ring weft was moved from spinner to weaver would explain why contemporaries noted spinners complaining that warping beams and skips were not returned from the weavers, but did not hear them make the same complaint about bobbins.67

The relatively small size of the transport cost premium on warp yarn explains Oldham’s lack of interest in paper tube rings. Notwithstanding that transport costs acted as a constraint, the absolute reduction in transport costs that could be gained by using paper tubes for warp yarn was small. This means that paper tubes would only have needed a small drawback to outweigh the benefits they offered in terms of lower transport costs. It appears, in fact, that paper tubes had a number of disadvantages. One of the few contemporary authors to mention paper tube rings, Melvin Copeland, noted that ‘paper tubes are used instead of wooden bobbins in some ring

spinning mills, but the bobbins yield better results’. 68 Mule spun warp also retained an advantage over paper tube ring warp because mule warp packages contained more yarn than ring warp packages, in that both have approximately the same total volume, but the latter contains a hollow paper tube at its core. 69 This means that mule cops would not have to be changed as frequently when being wound onto warping beams, lowering costs to the warper. It is also worth noting that Lancashire was not alone in ignoring paper tubes. Japan, the other internationally successful industry with vertically specialised spinners, did not adopt paper tubes even though they were large users of ring spindles .70 That neither Lancashire nor Japan adopted paper tubes suggests that they were not a good solution to the problem of transport costs.

ACCOUNTING FOR RINGS

It has long been clear that the lower transport costs associated with mule spun yarn ensured that yarn spun for export was effectively reserved for mule spinning. Similarly we already knew that the mule was much the better machine for all counts above the low 40s. This paper has shown that the technical complementarity between mule and power loom ensured that almost all weft yarn was spun by mules. Further, we have shown that transport costs affected specialised firms in Oldham, and, to a lesser extent, the neighbouring districts of southern Lancashire, obliging them to use mules for coarse warp. In contrast firms with weaving capacity nearby (whether integrated or co-located) were able to use rings to produce sub-40 warp yarn. We will now show that this analysis is compatible with both the overall gross investment pattern of the industry between the invention of the ring in 1880 and 1907, and with the total stock of spindles in that year.

Gross investment figures can be drawn from the 1907 Census and from Saxonhouse and Wright.71 Table seven compares these investment figures with those predicted by our sectoral breakdown and sector specific estimates of ring adoption rates. As can be seen, the predicted and actual investment figures are very similar, with the model overpredicting the adoption of rings by less than 2 percent of total investment.

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Notes: Co-located firms includes integrated firms. Figures do not sum owing to

rounding.

Sources: Row 2: Saxonhouse and Wright, “New Evidence,” p. 511; Row 3 & 4: col. 2,

Sector sizes from table 4 row 16 and 17 respectively, multiplied by investment rates from table 6; cols. 3 & 4 from table 6. Row 6: Saxonhouse and Wright, “New Evidence,” and 1907 Census, see text.

As well as assessing our results by dividing the industry by firm type, we can also divide the industry by product type. We noted that rings would have been used only occasionally when producing yarn to be exported, weft yarn, warp yarn produced by isolated firms, as well as supra­40 warp yarn produced by integrated and co-located firms. In contrast, without any constraints to their take-up, and given the possibility of shifting well functioning mules from warp to weft

production, we would expect all sub-40 warp yarns produced by non-isolated firms to be spun on rings. Since we know the relative size of these sectors in 1906, we can allocate rings and mules to these sectors as predicted above; table eight compares the results with the observed stock of spindles in 1907.

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Notes: Co-located firms includes integrated firms. Figures do not sum owing to

rounding.

Sources:

Row 2: col. 3: 1907 Census, includes yarn for lace, hosiery and elastic webbing, see text.

Row 3: col. 3, table 3; col. 4 & 5, Saxonhouse and Wright, “New Evidence,” p. 511.

Row 4: col. 3, 1912 Tariff Board Report, see text; col. 4, Worrall Directory, see text.

Row 5: col. 2, 1912 Tariff Board Report, see text.

Row 6: col. 3, table 4, row 17, col. 4 & 5, table 6, col. 4.

Row 7: col. 3, table 4, row 16.

Row 8: sum rows 2 to 7

Row 9: UK Census of Production 1907, p. 293

It is clear that our predicted patterns of behaviour are a good explanator of the stock of rings and mules in Britain. This gives us confidence that the overall breakdown of the industry presented here, and our assessment of the incentives and constraints faced by each sector, are correctly characterised.

CONCLUSIONS

This paper has shown that many of the previous ideas used to explain the slow take-up of rings in Lancashire are incomplete. We are now, however, in a position to be clear about the reasons for Lancashire’s continued and positive preference for the mule. The principal reason was Lancashire’s greater emphasis on fine cottons. Lazonick records that 42 percent of Lancashire’s yarn was of counts finer than 40, the 1906 Enquiry data gives a figure of 44 percent, while Saxonhouse and Wright’s data suggests that 53 percent of new machinery were for counts of over 40.72 In contrast only 8 percent of yarn in the United States was of such counts.73 Although it was technically possible to spin these higher counts on rings, contemporary literature is unanimous that the mule was the better machine. There is a second demand side factor that favoured mule spinning: the large demand for yarn exports, both to be woven abroad, and to be made into lace and knit goods elsewhere in Britain. The mule’s ability to produce lightweight packages consisting entirely of yarn made it well suited to this sizeable market niche. As table eight shows, these two demand side factors together ensured that a little over half of Lancashire’s yarn would be spun on mules.

Supply side factors, as well as demand side factors, mattered too. That rings were adopted at all shows that the unit labour cost saving gained by replacing male mule spinners with female ring spinners outweighed the extra cost of buying the slightly better raw cotton needed for ring spindles. But very few firms, integrated or otherwise, used rings for weft. Ring weft, unlike mule weft, had to be rewound to make it shuttle ready. In this case the labour cost saving was insufficient to outweigh the combination of the raw cotton and rewinding premiums. There is a sense, then, in which wage moderation on the part of mule spinners was sufficient to keep mule spinning as the method of choice for weft production, but insufficient to prevent ring spinning becoming important in warp production. Second, the additional transport cost of moving ring warp was sufficient to make the decision between ring and mule at best marginal for those firms

that needed to move their yarn any distance to the weaver. This factor was, however, relatively unimportant: even had the transport cost premium been eliminated altogether, the figures in table eight show that Lancashire’s spinners would have used just 3.5 million fewer mule spindles, that is, an eight percent fall in the total stock of mule spindles.

APPENDIX

CONVERTING EMPLOYMENT FIGURES INTO EFFECTIVE SPINDLE FIGURES. CONVERTING EMPLOYMENT FIGURES INTO ACTUAL SPINDLE FIGURES.

RING SPINNING

The number of spindles is calculated by multiplying employment data by the number of spindles per operative. The numbers of spindles per operative are derived by dividing data on weekly earnings by the Universal Wage List, which gives the rate paid per spindle tended. We use Saxonhouse and Wright’s data on the count distribution of rings to average the count specific spindleage numbers.

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Sources: Col 2: 1906 Enquiry, p. 30.

Col 3: Jewkes and Gray, Wages, p. 121.

Col 5: Saxonhouse and Wright, “New Evidence,” p. 511, sub-divided pro-rata where necessary

Notes: Col 4 equals col. 2 divided by col. 3.

The average is the average of column 4, weighted by column 5.

MULE SPINNING

John Jewkes and E.M. Gray give the number of spindles on typical new mules in Oldham and Bolton at ten yearly intervals.74 We use the figures for new mules installed in 1886-7 as a proxy for all mules in place in 1906. Mules lasted some 50 years,75 and the mule sector was growing relatively slowly in this period,76 so an average age of twenty years seems reasonable. In any case the growth in spindles per mule was only around 1 percent per year,77 so mis-estimating the average machinery age will yield only a small mis-estimation of the capital to labour ratio. We weight the figures for Oldham and Bolton (1044 and 936 respectively) by the ratio of mule spinners in each town as given in the 1906 Enquiry (3165 and 1806),78 remembering that each spinner tended two machines.79 This tells us that each mule spinner and his team tended 2046 mule spindles.

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Spindles: rings: Jewkes and Gray, Wages, p. 121, Saxonhouse and Wright, “New Evidence,” p. 511; mules: Jewkes and Gray, Wages, p. 205.

CONVERTING ACTUAL SPINDLE DATA INTO EFFECTIVE SPINDLE DATA

Different types of spindle produced different amounts of yarn per hour. Following the literature, we use one coarse mule spindle as our numeraire spindle, and covert other spindles into coarse mule equivalent spindles, which we term effective spindles. For sub-40 counts ‘effective spindles’ are exactly analogous to ‘mule equivalent spindles’. More generally the definition of an effective spindle is one that produces an equivalent length of yarn per hour, so data for effective spindles is a proxy for yarn output.

For ring spinning, we use the standard assumption that the output of one ring spindle was equal to that of 1.45 coarse mule spindles. 80 For mule spinning Jewkes and Gray give count-specific information on the time taken to complete three cycles of the mule, the traditional way of measuring mule speeds. We use the Saxonhouse and Wright installation data to construct a weighted average for sub-40 counts, and in the absence of further data, we use linear weights for averaging data for finer yarns.

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