Polyester fibres

While pursueing the studies and the research works begun but left unfinished by Carothers, the British chemist John Rex Whinfeld with the co-operation of his young assistant James J.Dickson invented a method to produce polyester fibres from terephtalic acid and ethylene glycol, and applied for a patent on July 29, 1941.

This new polymer was suited to produce extremely fine, soft and strong filament yarns, but it was only in 1949, after the second world war, that a pilot plant for the production of polyester fibres was put on stream in England. The commercial production started both in USA and in England in 1953.

 

Polyester is the most common synthetic fibre and is marked by a high growth rate. At present polyester production (filament yarn + staple) accounts for 60% of the total production of synthetic fibres.

In 1998 polyester world production amounted in fact to 16 million tons (9 million tons filament yarn and 7 million tons staple).

Up to 1975, polyester was produced on ethylene glycol (EG) and dimethyl terephtalate (DMT) basis; later also a second method based on terephtalic acid (TPA) was used. Also the discovery of polyester marked a new milestone in the industrial revolution, because this fibre has deeply changed the textile industry, imposing itself for its great versatility. Either pure or in blend with cotton and wool, it gave rise to new types of clothing and furnishing fabrics with interesting easy-care properties.

A further advantage was provided by the development of inherently flame-resistant polyester types, which allowed its wide application in products where fire resistance is a must: furnishing and in particular curtainings, industrial textiles and protective clothing. These special fibres, which resist or slow down flame propagation, retain an agreable textile handle.

Polyester has excellent properties: dimensional stability, high tenacity, good resistance to light and weathering. Beside having increasing success in woollen, worsted and cotton-type apparel fabrics, polyester fabrics find wide application in household textiles and in nonwovens.

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Polyester Fiber Glass Waste – How to Reuse

THE REUSE OF THE ARMED POLYESTER FIBER GLASS WASTES
P. Negrea, G. Mosoarca, M. Ciopec, L. Lupa
University „Politehnicall Timisoara, Faculty of Industrial Chemistry and Environmental Engineering,
Victoria Square, no.2, 300006, Romania, E-mail: lavinia.lupa@chim.upt.ro
Key words: PFG, clinker, incineration, waste management
ABSTRACT
The production evolution of the unsaturated and armed polyesters fiber glass (PFG) is determinate by the advantages offered by this material: weight reduction of the pieces, resistance to the chemical agents and bad weather as against the metals objects, energy consume reduction needed for the finite pieces obtaining by simplification and removal of a lot of production phases, increased work productivity, accessible price of the materials.
The prime materials used to the production of the plastic armed materials with glass fiber are: unsaturated polyester resin, styrene, initiator (per benzoate tert butyl), inhibitor (parabenzquinones), viscosity reduction, zinc stearate, filling materials (aluminium hydroxide, calcium carbonate), pigments (zinc sulphur, titan dioxide, and iron trioxide), thickened (magnesium oxide in resin, fiber glass, polyethylene folly).
The use domains of these materials are: body elements, compounds for automobiles, compounds for micro wave, and boxes for electric junction, stadium chairs, and waters basins.
The chemical analyze, caloric content and thermal analyze made on this armed polyester fiber glass wastes shows the incineration possibilities of these in the furnace of the cement obtaining, the resulted oxides inlet in the clinker composition.

1. INTRODUCTION
The man, in his researching of study and use of new materials, which can replace the traditional materials sometimes with unsatisfactory proprieties and which are more often hard to procure, find the unsaturated and armed polyesters fiber glass.
The unsaturated polyesters resins, in the commercial form are a solution of unsaturated polyesters in a monomer (solvent reagent) with who copolymerise making a reticular structure (the reaction of the polyesters strengthening).
The thermo active macromolecular compounds are synthetic resins of poly condensation, with not such a big molecular mass, which contain groups capable to react by adding of some suitable components or under heat action.
The proprieties of the thermo reactive polymers to pass, under heat action, in an insoluble and infusible form, constitute the base of these products. By mixing with different adding, under pressure, at a specific temperature, the material become plastic, take the form of the stamp, of the vessel in which is put and, because of the reaction which take place, is obtained the product with three-dimensional structure.
The processing of different objects and bench-mark from unsaturated polyesters resins can be realised using very different technologies, in which the resins reticulation takes place at the ambient temperature or at heating, in stamp made by different materials, function of the choose technology.
The armed polyester constitute in present the most important apply of the unsaturated polyesters resins. For the use of the polyesters in others purposes is necessary to begin with the preparing of some compositions and half-finished in discontinue regime of processing.

The resin material used to the obtaining of some armed bench-mark with glass fiber is named Sandwich Material Compounds (S.M.C.).
The preparing of this is made after the next phases:
- The dissolving of the dust resins;
- The dissolving and mixing of the peroxides;
- The cutting of the glass fiber and performing of the glass fiber armed;
- The processing of the pressing ass and rolling;
The purpose of the paper is the studies regarding the reuse of the armed polyester with glass fiber (PAFS) wastes. For this were made chemical analyses of the prime materials and of the resulted wastes after the technologic process of S.M.C. obtaining.
The resulted wastes are of three types:
- the wastes resulted after clipping
- the wastes resulted because of the unsuitable (S.M.C.) material from the quality point of view - the wastes resulted because of the rebut which appear during the technological flow.
For the obtaining of pastes ease to mix is used pigment based on zinc sulphur (with colour) and iron oxides (yellow and red colour).
The selected technological process (Figure 1) contains the next two steps:
a) the preparing of the working material, of the armed polyester with glass fiber;
b) the processing of the armed polyester with glass fiber in stamp;

2. PHYSICAL-CHEMICAL ANALYSE OF THE PRIME MATERIAL
It is weight in a melter a well defined quantity of the used pigment. The melter is put in a burning furnace, in the first phase at 500°C and than at 800°C for the removing of the organic part of the pigment. It is determined the loss at the burning. The resulted product after the burning was dissolving in HCl solution at heating. After dissolving the metals (Fe and Zn) are analysed by atomic absorption spectrometry using a spectrophotometer Varian SpectrAA 110.
The obtained results after the physical-chemical analyse are presented in table 1.

3. THERMAL AND IR ANALYSE OF THE PAFS WASTES
The obtained product is submit to the thermal analyse, using a thermo gravimetric balance Netzsch TG 209, in the view of final temperature of burning establishment.
Figure 2 illustrates the thermal behaviour of the product. When the product is non-isothermally heated with a constant heating rate of 5°C/min up to 1000°C, in the sample take place two processes with mass loss. The first procces occurs in the range of temperature 170-487°C with a mass loss of 33.67% in three steps with maximum rates at 233, 333 and 425°C. The second process takes place between 618-772°C, with maximum rate at 717°C and a mass loss of 12.21%. At 985°C the residue is of 50.80%.

4. THE PAFS WASTES ANALYSES
It is weight a determined quantity of the wastes (PAFS) in a melter, which next is put in a furnace at 800ºC for the removing of the organic impurities present in the waste. The obtained mass after burning was dissolving in HCl solution at heating. The resulted solution after filtration is analysed. The experimental data obtained are presented in table 2.

5. CONCLUSIONS
The processing process generates important quantities of PAFS wastes which could not be direct reused.
Having in the view the chemical composition of these waste these can be incinerated in the furnace of the cement obtaining, because they have a good caloric capacity, and from the incineration process the major resulted oxides are: calcium oxide, silicium dioxide and a series of other oxides in small quantities.
The resulted wastes must divide and compacted in the view of the facilitate the introduction in the cement obtaining furnace.

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Treatment of Polyester Fabric

Continuous Modification Treatment of Polyester Fabric
by Dielectric Barrier Discharge
Ren Zhongfu¹, Qiu Gao², Ren Xiandong¹, Wang Zhonghua¹
(1. Jining Medical College, Jining, 272000 ; 2. College of Basic Science, Donghua University, Shanghai, 200051)
Abstract: Continuous modification of polyester fabric was carried out by dielectric barrier discharge (DBD) of Ar-O2 (10:1) at atmospheric pressure. The results revealed that the dyeability of polyester fabric was dramatically improved, and its reflectivity of light was considerably decreased. The spectral value (K/S) was found to be increased by about 50 ﹪. The dye up-take was found to be increased by about 18 ﹪. However, the dyeing fastness was the highest degree, that is to say, despite the large increase of the up-take, the dyeing fastness was not be affected by the modification treatment of the DBD. SEM studies showed that the smooth and glossy surface of polyester fibre became rough and deep in colour after treatment by the reason of etching action of the discharge. XPS studies showed that Ar-O2 discharge could help to form a few carboxyl groups on the polyester fibre surface.
Keywords: dielectric barrier discharge, continuous modification treatment, dyeability, reflectivity, polyester fabric

1. Introduction
The requirement of vacuum systems for low pressure plasma has been a burden for the textile industry, hence there is now an enthusiasm for plasma generated at atmospheric pressure. Dielectric barrier discharge (DBD) is effective in generating uniform plasma at atmospheric press. In addition to its freedom from the reliance on vacuum systems and adaptability to continuous industrial production, DBD at atmospheric pressure costs much less than low pressure plasma, consequently, DBD will play an active part in future textile industry[ 1 -7].
Polyester is one of the most popular principal synthetic textile materials nowadays, which many people are very fond of at present. Yet it has some defects in practice. Because of its high molecule crystallization and deficiency of reactive group on fibre surface, polyester fabric is rather reflective and dye-resistant to some extent, especially not suitable to be dyed in deep colour, and all these affect its common application and appearance.
To meet the requirements in technical textiles, modification of polyester fabric is important to achieve improvements in surface properties, such as the promotion of dyeability and the reduction of reflectivity. DBD technology can effectively achieve modification of near-surface region without affecting the desirable bulk properties of material. In the experiment, polyester fabric was continuously treated by DBD of Ar-O2(10:1) using a simple system at atmospheric pressure. This paper, firstly describes the experimental system, then presents detailed results of the continuous modification effects of DBD on polyester fibre surface, this is to say, the spectral value (K/S), the relative dye up-take, the dyeing fastness, the scanning electron microscope (SEM) and also the X-ray photoelectron spectroscopy (XPS) of polyester fabric, finally, this paper analyzes and studies the likely mechanisms of the
modification processes.
2. Experimental set-up
The set-up of continuous modification treatment is shown in Figure 1. Two plane-parallel copper electrodes covered with dielectric material (usually mylar or glass) are separated by a uniform gap. An A.C. power supply is connected to the two electrodes to enable discharge. The gas passes a flow meter that shows its flow rate, and then is distributed to the discharge gap. Cooling liquid goes through the hollow electrodes, so that the heat produced during discharge can be emitted promptly, and the temperature in the gap would not rise too high for synthetic material. Discharge voltage, discharge power, and charge current can be measured with measurement system. The material is fed by a conveying system into the gap continuously, and the treatment time can be controlled by adjusting the conveyer’s moving speed. The whole set-up is fixed in a transparent chamber.

In the experiment pure Argon was not chosen as discharge gas on account of its inertia, instead it was mixed with a little oxygen. The addition of a little oxygen was to introduce oxygen groups into polyester fibre surface via chemical reaction for the reason of oxygen activity. In the discharge gas the ratio of argon to oxygen is 10 to 1 in volume, so that the discharge gas is formulated into Ar-O2(10:1) in this thesis.
3. Results and discussions
Polyester fabric samples treated for various time by discharge were dyed with blue disperse dye under high temperature and high pressure. The change of K/S value is shown in Figure 2. It can be seen that the process of continuous modification treatment resulted in a large increase of K/S value. In the initial time of treatment the K/S value rised sharply, then slowly, and after about 1 minute it reached the maximum. The maximum of K/S value was dramatically increased by about 50 ﹪ in comparison with that of untreated sample. The increase of K/S value indicates the improvement of dyeability and also the reduction of reflectivity.
The plot of the relative dye up-take is depicted in Figure 3, which is somewhat parallel to

The increases of the K/S value and the dye up-take both illustrate that the discharge of Ar-O2 can satisfactorily improve the dyeability of polyester fabric. To test the dyeing fastness of polyester fabric treated with discharge, the rubbing dye fastness was tested, as is shown in the table 1. The treatment time was 1minute. Reaching the 5degree (the highest degree), the two kinds of rubbing dyeing fastness of polyester fabric treated by discharge remained the same as that untreated, which is very significant. By the way, the rubbing dyeing fastness of the untreated polyester fabric is usually the highest degree. So it can be concluded that even though the dye up-take was increased, the dyeing fastness wasn’t be affected by discharge modification treatment.

In preceding part of the paper it is illustrated that discharge of Ar-O2 can satisfactorily improve the dyeability of polyester fabric under the condition of keeping dyeing fastness. In order to study further the likely mechanism of the discharge modification to polyester fabric surface, and also to analyze the surface state change during treatment, the samples before and after treatment were analyzed with scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). As is shown in Figure 4 (a) the polyester fibre surface before treatment looks smooth and glossy. And the fibre surface treated for 1minute is shown in Figure 4 (b). It was rougher and deeper than before treatment. The roughness and deepness was due to etching process, which helped to the increase of the K/S value, and the decrease of reflectivity as well.
Figure 5. shows C(1s) XPS spectra of polyester fibre surfaces before and after treatment by
Ar-O2 discharge, the treatment time was 1minute too. Binding energies characteristic of different levels of oxidized carbon are assigned as follows: saturated carbon ( C-C/C-H ) at 285.0eV, carbon bonded to hydroxyl group or doubly bonded to one oxygen atom (C-OH/C=O) at 287.2eV, and carbon bonded to carboxyl group (C-COOH ) at 289.3eV[8]. The Figure 5. (b) has one a little

bigger shoulder at higher binding energy than Figure (a), which indicates a little more carboxyl groups on fibre surface after treatment. The XPS datas show that Ar-O2 discharge can help to form a few carboxyl groups on polyester fibre surface. Carboxyl group is hydrophilic, and its formation on surface is advantageous to the improvement of polyester fabric dyeability to a certain extent.

4. Conclusion
The continuous modification of Ar-O2(10:1) discharge can improve polyester fabric dyeability
and reduce its reflectivity dramatically. The K/S value and dye up-take was enormously increased. In spite of the large increase of dye up-take of the treated fabric, the rubbing dyeing fastness still reached 5 degree (the highest degree) as well as that untreated, so it can be concluded that modification treatment of Ar-O2 discharge does not affect the dyeing fastness of polyester fabric. The discharge has two kinds of modification action on polyester fabric surface, i.e. etching and chemical reaction. Due to etching the smooth and glossy surface of polyester fibre became rough and deep in colour, in other words, its reflectivity was decreased, which corresponded with the large increase of K/S value. On the other hand, chemical reaction can introduce a few -COOH groups， which is hydrophilic, into the polyester fabric surface, and the formation of -COOH group is another positive factor to improve polyester fabric dyeability.

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Antibacterial Polyester Fibre - Analysis

A NEW POLYESTER FIBRE
WITH ANTIBACTERIAL ACTIVITY
G. Salvio
MONTEFIBRE SpA (ITALY)
Introduction.
Since the last part of the century an increasing improvement in qualitative standards of human lifestyles has brought to a greater sense of comfort, and cleanliness. People are more and more looking for fresh public living surroundings and a higher level of hygiene in home areas. A wide class of micro-organisms coexists in a natural equilibrium with human body and living environments, but a rapid and uncontrolled multiplication of even non pathogenic microbes can seriously compromise the hygienic and healthy personal standards. Because of their capillary spread in the human living spaces, the textiles have been involved in this research of a growing quality of hygienic living conditions.
Actually, several combinations of temperature, humidity and other climate factors added to the presence of dust, soil and fat-stains on the textile surfaces can transform the textiles themselves in an optimal enrichment culture for a rapid multiplication of micro-organisms. In such a case two contemporary effects occur: the first is an uncontrolled proliferation from textile surfaces into the surrounding environment with a consequent increase of bio-burden level and potential health risks or, at least, of discomfort for the unpleasant odours produced by high concentrations of micro-organisms; the second one is the onset of degradation phenomena as colouring and discoloration of the textile
fibres. Many efforts have been performed by textile industry with the aim to score two goals: the protection of the living environments and of the textile fibres from an uncontrolled proliferation of micro­organisms like bacteria.
2) – Micro-organisms action on textile surfaces.
In the broad spectrum of existing bacteria there are pathogenic and non-pathogenic organisms. Both of them can multiply abnormally on the textile surfaces with an accumulation that compromises the hygienic cleanliness.
Tab.1 shows some examples of pathogenic and non pathogenic micro­organism.


The proliferation of pathogenic micro-organisms has to be fought for
the physiologic impact to the human health, while non pathogenic micro-organisms have to be controlled for the visual, olfactory and tactile effects produced by their metabolism.
The textile materials, on which source of nutrients are present (food contamination, oil, fat, protein, sugar, skin secretions like sweat and sebum etc.) become a medium for a rapid multiplication of micro­organisms. Many bacterial colonies produce, in their metabolism, coloured pigments that protect them against light and UV radiation.
In fig. 1 some colouring pigments, synthesized by different bacteria, are reported:

These substances cause colouring of textiles through adhesion to the surface. The pigments attached to the fibre cannot be adequately
removed by normal washing and, as time passes, colour stains firmly bond to the textile with no possibility of removal, even after repetitive washings. In some cases, according to the type of fibre material and attached pigment, only bleaching agents can be helpful, but it is quite difficult remove the pigment even by the oxidation and reduction reactions of the bleaching process.
In their growth on a fibre, micro-organisms can produce volatile compounds of unpleasant odour as decomposition by-products of their feeding. Spilled foods and drinks, dirt, dust, organic stains, secretions from the human body like sweat and sebum are decomposed from bacteria with a production of bad smelling components like : fatty acids (acetic, propionic, butyric, valerianic, caproic), n-methylamines, ammonia, aldehydes, sulfides, mercaptans, aromatics and lactones. Other micro-organisms transform the human steroid hormones in foul ketones and steroids with the same odour of urine.
3) – Bio-active fibres.
A general term that is adopted to indicate the textile fibres with activity against micro-organisms growth is “bio-active fibres”. A distinction can be made according to the possible end-uses: hospital uses, home textiles, carpets, furnishing, mattress and pillows fillings, air-liquid filters, non­wovens, protective clothing, sportswear etc. Each of these application fields will demand a different bioactivity performance from the fibre. Man-made antibacterial fibres are manufactured by two basic methods: the first is kneading antibacterial additive during the spinning stage and the second is an after-treatment method in which an antibacterial agent solution is used.
In the mixed spinning technology, the antibacterial agent is supplied
into the polymer stream before the spinneret or blended into the spinning polymer feeding. The additive characteristics have to be compatible with spinning conditions (e.g. particle diameter, heat and chemical stability, no degradation interactions with polymer, lack of adverse effects on fibre quality). A reserve of antibacterial additive is englobed into the fibre and, after migration to the surface, it can practise its bioactivity against micro-organisms.
In the post-process finishing technology, the most common techniques to apply antibacterial agents are: spraying, immersion, padding and coating. The textile surfaces are often treated in the final dyeing and finishing stages of their manufacturing process. Antibacterial agent is linked to the surface through physical bonds or anchored by a cross-linking on the fibre. The most used additives are based on organic compounds like halogenated salicylic acid, anilides, organotin compounds, quaternary ammonium compounds, organosilicon quaternary ammonium salts, and quaternary ammonium sulphonamide derivatives . Since most of them are highly water soluble and weakly anchored to the fibre surface, they have to be constantly reapplied.

According to the manufacture technology and the antimicrobial agent nature, the antibacterial fibres can exhibit two kinds of bioactivity mechanism: an elution mechanism and a non-elution mechanism. In the first the additive gradually migrates out from the fibre to the solvent external medium, while in the second mechanism it does not dissolve out. Although, sometimes, the two kinds of mechanism coexist in the antimicrobial activity of a bioactive fibre, generally, one of them is the predominant.
4) – Antibacterial activity tests .
Antibacterial activity of bioactive fibres is not immediately evident, but it can be evaluated by opportune test methods. Since the early appearance of bioactive fibres, several standard methods have been defined and, at the moment, there is not a unique test protocol that is suitable for all the sorts of the antibacterial fibres. Each of the existing methods has its own approach and application field, so that, if two of them are adopted to characterize the same antimicrobial textile, they often show opposite results.
A first overall classification is carried out on the basis of the kind of the evaluation of the micro-organism population reduction: quantitative and qualitative. In the quantitative methods the number of bacteria, still living after an opportune contact time, is counted. Besides, the quantitative evaluation can be differentiated further in other two classes according to the main test conditions. For example, a small amount of liquid culture medium is used to cover a specimen in the static method ATCC 100, while the fibre specimen is immersed in a larger amount of liquid culture when the dynamic Shake Flask Test Method is carried out.
In the qualitative methods the test specimen and an untreated control are pressed into intimate contact with an agar culture medium inoculated with the test bacteria solution. If antibacterial activity is present, it will be possible observe a clear zone around the treated sample comparing to the zone of bacterial growth around and over the untreated control sample after the same contact time.
These qualitative methods provide a formula to measure the inhibition zone width, but this is a qualitative evaluation and it can not be considered as a quantitative indication of the antibacterial activity.
The most important antibacterial activity test methods, with their main

The results that these methods can give depend strongly on the antibacterial additive mechanism of activity and on the hydrophobic or hydrophilic nature of the bioactive fibre. In each analysis, the measurement of the activity of a reference sample of nature similar to the antibacterial fibre but without additive must be carried out.
After the time contact, three cases of bioactivity can present as result
of testing a textile:
1) a significant increase of the initial bacteria population
2) an inhibition of the bacteria growth comparing the antimicrobial product with the control sample for which there is a multiplication of test bacteria population inoculated at the beginning of the time contact.
3) a quantitative reduction of the number of test bacteria inoculated at the beginning of the time contact.
The second and the third cases indicate an antibacterial activity from the bioactive fibre and the terms used to differentiate the two performances are biostatic and biocide.
5) – Montefibre Terital Saniwear.
Only inorganic compounds can be used as antibacterial agents to add bioactive functionality to the polyester fibre directly in the spinning stage due to heat-resistance limitations.
Montefibre has now developed an its own technology to impart antibacterial activity to the regular TERITAL polyester staple fibre. The required amount of antibacterial additive is mixed to the melt polymer stream before spinning.

The additive used in TERITAL Saniwear manufacture has a high surface area of active ingredient so that it is possible to reduce the overall loading of antimicrobial agent. That means no impacts onto fibre quality and environmental benefits. The additive is a photo stable inorganic powder and it essentially consists of an active ingredient deposited on a core particle which has bio-activity as well. Due to its inorganic nature the antimicrobial agent has a high heat and chemical stability. The easy dispersion in the polymer matrix and a barrier layer
that avoids an uncontrolled release of the active ingredient are two key elements for the long-lasting antimicrobial effect provided to the fibre. In Tab. 3 some MIC values (Minimum Inhibitory Concentration) of the antimicrobial additive used for Terital Saniwear are reported:

Antimicrobial additive is EPA approved, FIFRA registered and shows low toxicity.
Metal ions inhibit the multiplication of micro-organisms by two mechanisms. In the first, they destroy or pass through the cell membrane, and bond to the –SH group of cellular enzymes. The consequent critical decrease of enzymatic activity produces an alteration of the micro-organism metabolism and a suppression of their growth, up to the cell death.
In the second possible mechanism, the formation of active oxygen occurs according to the following scheme:

The metal ions catalyse the production of oxygen radicals that destroy
molecular structure of bacteria. Such a mechanism does not need a direct contact among antimicrobial ingredient and bacteria, because the active oxygen diffuses from fibre to the surrounding environment. Bacteria are not exposed permanently to radicalic oxygen and, thus, this ionic additive, with its activity mechanism, does not seem to facilitate the selection of resistant strains.
5.1) – Terital Saniwear properties.
Studying the antibacterial product, Montefibre has initially started individualizing two main potential application areas: the cotton type spinning-weaving and the filling sectors. Thus, two classic fibre counts have been chosen in the first development stage: 1.7dtex for the cotton type and 6.7 dtex for the fibrefill type.
In Tab. 4 textile properties of standard TERITAL polyester staple fibre and TERITAL SANIWEAR are showed. There is no significant decrease in mechanical characteristics of the fibre and, thus, it can be transformed along the textile chain like regular polyester.


The mechanical wadding properties remain practically constant passing from the standard to the antibacterial fibre.
Saniwear can be used in mixture with standard thermo-bonding fibre, as the regular fibre, for thermo-linked wadding. Dynamic-mechanical performances of the obtained samples are compared in Fig. 2

Antimicrobial additive tends to give a slight yellowing of the fibre, but, in the case of Terital Saniwear, the kind of added agent does not produce a dramatic variation. Colorimetric characteristics of the


5. 2) – Antibacterial Test Method for Terital Saniwear.
To evaluate the antibacterial properties of all the samples containing TERITAL Saniwear, the Shake Flask Test was adopted. The choice of this method is connected to the hydrophobic nature of polyester fibre
and to the additive activity mechanism.
SN 195920 and AATCC–147, being static methods, are directly dependent on the rapid leaching rate of the antibacterial agent from the fibre into surrounding environment. The additive used by Montefibre is basically immobilized and slowly diffusing. It does not diffuse at an efficacious rate, under normal conditions of testing, and, thus, these methods are not appropriate for the TERITAL Saniwear.
Besides, the high ratio liquid/fibre in the Shake Flask method allows the right testing condition for a hydrophobic surface as is the case of polyester. Finally, this method ensures (by a constant agitation) an intimate contact between the micro-organisms and the antibacterial textile surface and, for this reason, it is the most suitable in the evaluation of blended fibre samples.
In the operating procedure 75 ml of a bacteria inoculum are added to a test flask containing 0.75 g of the test specimen. After sampling at time zero, the number of the bacteria are counted by placing and incubating on an agar plate. The same procedure is repeated for a control sample. Then, all the flasks are shaken for 24 hours and the number of living bacteria are counted. A percent reduction of bacteria is determined using the following formula:
Reduction (%) of bacteria: (B-A)/ B * 100
where: A = CFU/ml (units forming bacteria colonies/ml) after 24 h. B = CFU/ml (units forming bacteria colonies/ml) at 0 h.
5. 3) – Terital Saniwear’s antibacterial activity.
In Tab. 8 the antibacterial effect of TERITAL Saniwear against some bacteria strains is reported as percentage reduction obtained in the Shake Flask Test. In each determination a reference non-antibacterial sample is tested showing a bacteria growth after the same time contact.

The antibacterial effect of TERITAL Saniwear is maintained also when it is blended with other natural or synthetic non-antibacterial fibres, as regular polyester and cotton. The results of the bacteria reductions obtained at different level of Saniwear in the blends are showed in Tab. 9 (polyester blends) and Tab. 10 (cotton blend):

Testing the antibacterial activity of blended fabrics after bleaching, dyeing and finishing stages shows that Terital Saniwear is still effective in the inhibition of bacteria growth (Tab. 11):

5. 4 ) – Durability.
Terital Saniwear has a long lasting activity for the slow diffusion rate of the antibacterial additive kneaded in the fibre.
As measured in Montefibre laboratories, the release of the bioactive agent from the interior fibre surface, in the dyeing and washing processes, is really minimum and experimental data (reported in Fig. 5) confirm this evidence:

This controlled migration of the additive is confirmed by washing tests according to the standard EN 26330, using a ECE-detergent at 40 °C. Evaluation of the antibacterial activity after repeated washes, carried out on fabric samples containing Terital Saniwear, points out a permanent effect against multiplication of bacteria; some examples are reported in Tab. 12. A change in the surface dispersion of the antimicrobial agent can occur during washing cycles so that a new fresh amount passes from the interior reserve to the external fibre surface with a slight improvement of the antibacterial activity after the first washing steps.

5. 5) – Potential end uses and possible developments.
A broad variety of potential and interesting end-use applications of Terital Saniwear is described in Tab. 13, while the available antibacterial fibre types and some new Montefibre’s bioactive products - at the time being under development- are showed in Tab. 14:


6) CONCLUSIONS
Beyond some untenable claims, it is by now a widespread opinion - experimentally proved - that the antimicrobial textiles can contribute to the cleanliness and hygiene standard quality in the every day human life. The Terital Saniwear is an inherent, safe antibacterial fibre showing an effective barrier against micro-organisms proliferation on the textiles in which it is added.
The mechanical performances are very similar to those of the regular Terital and the durability of the antibacterial effect is ensured by the additive activity mechanism joined to the manufacture technology of the modified fibre. Saniwear can be used at a blending ratio suited to the application fields and to the requested level of antibacterial activity (bacterio-static/cidal).
Montefibre’s R&D, with its analytic-technical support, is really desirous and motivated to follow the customer’s creativity in exploring
all the possible market developments, in defining together the best transformation conditions of the new Terital Saniwear and in engineering fibre for specific end-use applications.

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