Bast fibres | Flax – Ramie - Jute

The main bast or stem fibres, which are fibres containing fibrous bundles in their inner bark, are: flax, jute, hemp, ramie and kenaf. We shall here limit us to some short hints at flax, ramie and jute, which are currently the three most widely used bast fibres.

Flax 

Flax is a herbaceous plant (Linum usitatissimum) of the Linaceae family, which is grown to obtain the most valuable vegetable fibre. It is part of the so-called bast fibres, as from their inner bark, called liber, fibrous bundles are extracted which, properly treated, are converted into fibres. As to the processing of flax, we refer to the chapter 4 'Bast fibre spinning technologies", which illustrates two different spinning systems: wet and dry spinning.

The linen fabric is characterised by a considerable moisture absorption, therefore linen items are particularly comfortable. Linen is employed for the manufacture of high-class fabrics for top quality household linen, apparel and also decoration fabrics.

In these last years the linen world production has gradually declined. In 1996, in Western Europe about 21,000 tons of flax yarns and 16,000 tons of linen fabrics were produced. Italy ranks first in terms of production of both flax yarns (6,800 tons) and of linen fabrics (9,100 tons), followed by Ireland, Belgium and France.

Ramie

Ramie is a bark or stem fibre, which use in fabric production dates back to ancient times; in the ancient Egypt, it was used as early as in 500 BC. At present it is mostly grown in China in form of white ramie; its production totals about 100,000 tons/year.

The ramie plant is a species of the Urticaceae family and resembles the flax plant; in fact it grows up to 2 metres height and to a diameter of 1-2 cm ; the fibres are distributed on a cortical layer situated just underneath the outer bark and are glued together by gummy and gelatinous substances.

Unlike other bast fibres (flax and hemp), ramie is not retted, because of the low corruptibility to micro-organisms of the organic substances glueing the fibres together, and because of the risk of fibre fermentation during retting, with ensuing tenacity loss.

Owing to its whiteness and silky lustre, ramie is the most beautiful cellulosic fibre. Its tenacity and the possibility of converting it into single fibres enable to produce fine counts, while its resistance to wear and to excess of moisture (rot) makes ramie fabrics extremely weather resistant.

Unlike flax, ramie does not show any tenacity loss in wet state. Its length can vary from 60 to 250 mm and its diameter from 10 to 100 µ: as such, it is the longest and broadest vegetable fibre. Its chemical resistance is better than that of other bast fibres; it reacts properly to bleach, which yields light, extremely pure colours and pearly shades.

Jute

Jute is obtained from the bark of some trees of the Tiliaceae family which live in Asia and in Africa and is grown mainly in Bangladesh. It is mostly used for weaving primary and secondary carpet backings and packaging materials.