CZ248292A3 - Process for producing flax yarn by wet spinning and the yarn obtained in such a manner - Google Patents

Abstract

According to the invention, the fibres originating from stripping are subjected to the following preliminary operations: a. cutting to a length of between 150 and 400 mm, b. preimpregnation with water, c. action of steam at a pressure of between 10 and 15 bars for a period of between 20 and 60 seconds, d. decompression to atmospheric pressure, e. washing and drying, which are subjected to the preparation stages on any type of material: linen, wool or cotton; the fibre sliver obtained is finally spun wet. The linen yarn obtained has the appearance and the structure of a linen yarn produced by the wet method and has a flexibility which makes it suitable for use in millinery and on a knitting loom.

Description

State of the art

Wet spinning is well known. It is based on fibers. originating from friction, either from flax in the true sense of the word, or from frayed unprotected flax, or from seed tow, which undergo preparatory processes such as combing and / or carding, sowing and drawing to form a sliver, ie a sliver which is fine and regular, of substantially parallelized fibers, whereby spinning is carried out by means of a flugelhorn, where the strand is transformed into a strand consisting of a slightly twisted strand and then a spinning machine for wet spinning.

The yarn obtained by wet spinning technology has a natural appearance and a specific view structure, which results from the presence of residual organic sticky substances and the manner of breaking and sliding of the elementary fibers against each other during the drawing process. However, the presence of organic sticky substances (pectins, hemicellulose, lignin ....), which allows the yarn to be improved, is characterized by a considerable disadvantage in terms of increasing its stiffness. Thus, the wet-spun linen yarn obtained in a traditional manner does not have sufficient flexibility • Ί ·· '- ⁴ “-: - ·; . - f <* r · 1 Γ * 'λ f “V ί significantly reduces its industrial sales.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process for producing linen yarn by wet spinning, which overcomes the above-mentioned disadvantages while retaining the appearance and texture of the wet knitted yarn while having sufficient flexibility to be useful in knitting.

This object is achieved according to the invention by a process for producing linen yarn by wet spinning, comprising preparing a fiber strand and wet spinning, which is based on the fact that the fibers coming from the screed are subjected to successive preparatory processes successively. cutting operations in the range of 150 to 150 mm

400 mm, pre-impregnated with water, application of steam under pressure from 1 to 1.5 MPa for 20 to 60 seconds, expansion at atmospheric pressure and washing and drying. The preparation of the strand can be carried out on any type of preparation device, namely flax, wool or cotton.

These pre-operations aim to substantially reduce the amount of organic binder materials while maintaining a sufficient amount to allow wet spinning while maintaining the natural appearance of the yarn. In addition, the combination of the aforesaid pressure steam treatment and wet spinning of the yarn provides a very good regularity of the residual binder distribution. It is this regularity and a smaller amount of binders that allow to achieve the desired result, i.e. increased flexibility while maintaining the traditional appearance and texture.

In addition, the provision by which the fibers are cut to a length in the range of 150 to 400 mm allows the preparation of the strand to be carried out on a preparation device which is not necessarily of the linen type but can be of the wool or even cotton type.

With the method according to the invention, it is thus possible to avoid, for example, the formation of nucleation.

: nany,> the British

1.

the patents GE-A 388 561, GB-A 476 569 and the patent specification

No. 633,421, processing methods in which the fibrous plant is subjected to pressure steam and then allowed to expand at atmospheric pressure followed by washing. However, it is a high-pressure treatment aimed at decorticating fiber plants in the form of straw, leaves, grass, i.e. to separate the bark or woody part from the fibers itself. The pressures used are in the range of 3.8 to 6.2 MPa.

It is also known to process a spawning linen of the abovementioned type, such as from European Patent EP 0 253 825, in which the steam is subjected to a pressure of the order of magnitude.

However, after the fibers have been subjected to a pretreatment consisting of impregnation with a basic or acidic solution. The object pursued according to this specification is to obtain flax fiber which is substantially free of woody components.

Thus, the object of the invention is quite different and the pressurized steam conditions are determined precisely so that a smaller amount of organic binder material persists but is nevertheless sufficient to allow a good wet spinning process.

Preferably, the wet spinning is performed with a draw in the range of 50 to 140 based on a strand that has not been subjected to passage on the flugel. Thus, it is possible to avoid the first spinning phase, which consists of spinning on the flugel, by simply and simply increasing the spinning delay without compromising the regularity of the yarn obtained.

Preferably, prior to wet spinning, the strand is subjected to an alkaline pretreatment which allows to improve the slip of the elementary fibers during stretching and to increase the uniformity of the distribution of the sticky substances.

Preferably, for example, the strand is subjected to an acid, e.g.

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The invention further relates to linen yarn obtained by the aforementioned method, characterized in that it has the appearance and structure of the wet-spun yarn and the flexibility sufficient for use in knitting on a knitting machine.

The invention is explained in more detail in the following by way of example of the production of wet spun linen yarn for use in knitting.

An example of an embodiment of the invention

The starting material consists of rubbing tow derived from the friction of the unlorn flax. For example, flax was harvested prematurely in the case of dew in the field. Compared to the normal dew, the unfinished flax still contains more and more woody substances, to the extent that the binder which binds the fibers between them could not be sufficiently decomposed by the bacteriological action of the dew.

The tow is subjected to a pretreatment by cleaning it with a fine carding machine from which it exits in the form of a powder. '? · -.- *. ·. · 'V ·'. * · · '· .->''' 6 · 7 '''*''.' ^Λ · -. .menu. The strand is cut into sections with a length of 300 mm. The shredded material is introduced into a reaction vessel, where it is impregnated with pure water, then subjected to hydrolysis in water vapor at a pressure of 1.5 MPa for 40 seconds. After this time, opening the outlet port of the reaction vessel causes a rapid opening by passing a pressure of 1.5 MPa to atmospheric pressure and thus expelling the flax through said port to a container containing a slightly alkaline time where it is washed and then rinsed.

After drying, the fibers of the flax thus processed are transformed into a 4g / m strand by passing through a preparatory machine by successively passing through a fine carding machine, passing through a GN4 spinning machine, two passing machines, a GN4 spinning machine and two passing machines GN5 without passing flugelhorn.

At the end of the preparation, the strand fineness is characterized by IFS 16.74 and CV% 5.07. It should be noted that with flax not3- 1-. -, ρ, 3.-,. .7, - -J -., -, 7 .-, 1,1-Ατ · .. - _; 3Γ; '1 ,,, .-:,., ---. 1.

folders using solution 2 ^to sodium carbonate .g'l,

Spinning. wet weaving on annular DC spinning machine in two stretching bands, · Cr pressure

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The strand passes into a container filled with cold water and is guided through the inlet as to the outlet of the drawing system by ceramic guides.

In a specific, but non-limiting, embodiment, the roller pitch is 80 mm for the rear zone and 60 mm for the front zone. The twisting is 410 t / m and the receiving rate is approximately 13 nt / nun. The flax yarn obtained has a metric number of 23, a strength of Pkm 17 (CV% 20 to 25) and an elongation of 1.6 to 1.8%.

This yarn, the appearance and texture of traditional wet předenému flax features comparatively high flexibility, making it eligible for use in conditions Jpřijatelňýčh for «work on knitting machines that- * · * ** *** ^C Λ 4 'V *' ~ Λ V? Λ. and. JJ, 'names of rounded ^^ and ^ classes' eligible for use in ^? 'knitting. ,; yq, - * - y '

The present invention is limited to the described embodiment, which 'serves only as a non-limiting example. Namely, the length 'stříhání'může' be determined by one skilled in the art depending on the preparatory, the circuit that is used ^in, eg flax, wool, or cotton. In addition, the strand may be subjected to various treatments such as bleaching prior to wet spinning, resulting in the manufacture of bleached flax yarn.

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Claims (3)

? 7 Τ Ε 7 O V Y Y A R O R Y A method for the production of linen spun yarn, comprising the preparation of fiber praraens and its wet spinning, characterized in that the fibers resulting from the friction are subjected to successive operations, namely cutting to length in range from 150 to 400 mm, pre-impregnation with water, pressurized steam from 1 to 1.5 MPa for 20 to 60 seconds, expansion at atmospheric pressure and washing and drying, and wherein the preparation of the strand is carried out on all types of equipment for preparation: flax, wool or cotton. Method according to claim 1, characterized in that the spinning after. The wet is carried out by an O-draw in the range of 50 to 140 based on - the strand (which ‘) has not been compromised by the passage on the flugelhorn. Způsob'jpódle third ^of claim 1 wherein the fiber friction that vy'tvŠlá EcoRI ^^ ⁷ tířenské tows are subjected to T '- ^ p ^ ed ^ n ^^ VAC to ^^^^^^^^ / fine carding machine. ^^^ T ^ i ^ l-labeled by-before \ ^J pře.děním ^ž'I, 5 l ^ ^fl ^ 3 ^ ^,, 5SR WÍákéňn'ý ⁱ 'undergoes alkaline r'prameň - ť, * «·,> '’'. ' <1 "," pre-treatment ", in particular sodium carbonate solution. 6. The method according to claim 1, characterized in that the fiber strand is bleached prior to wet spinning. · - ·· ΐ3 <, -. ^; · - “· - · in -'-- ... names with oxygenated water. The flax yarn obtained by the method of claim 1, characterized in that it has the appearance and structure of the wet spun linen yarn and has a flexibility making it suitable for use in knitting on a knitting machine.