AT507758A1 - YARN AND THREADS FROM BLENDS OF FIBERS AND ARTICLES THEREFROM - Google Patents

Description

PL0416, Lenzing AG

Yarns and threads made from fiber mixes and articles made from them

This invention relates to fiber blends in the form of yarns and cotton threads with Lyocell cellulosic staple fibers and articles made therefrom.

Methods of blending various types of fibers are known to provide certain articles with articles made therefrom. 10 From the Lenzinger Berichte, Vol. 42, March 1887, page 46, it is known that a blend of cotton and fibers of the viscose or modal type can improve the quality of the yarn. However, it was found that the tear resistance and elongation of the chamde depends only slightly on the viscose content (Lenzinger Berichte, Vol. 62, March 1967, page 46, 15 last paragraph, page 47-fig. 2).

Viscose and Modal cellulose fibers are made according to the viscose process. In recent years, the "amine oxide" or "lyocell process" has been developed as an alternative to the viscose process, wherein cellulose is dissolved without the formation of a derivative in an organic solvent of amine oxide, especially N-methymorpholine oxide (NMMO) ,

In this process, the solution of cellulose is usually extruded by means of a forming tool, whereby the solution is molded. Via an air gap, the shaped solution is passed into a precipitation bath, in which the shaped body is obtained by precipitating the solution. The shaped article is optionally washed after further treatment steps and dried.

Cellulosic fibers made from such solutions are referred to as "solvent spun" fibers and have been THE REPLACEMENT OF BISFA (The International Bureau for the Standardization of Man-Made Fibers) 30

PL0416, Lenzing AG

Designation "Lyocell" received. A process for producing lyocell fibers is described, for example, in US 4,246,221. The amine oxide process produces fibers characterized by high tensile strength, high wet modulus, and high loop strength.

Further possible solvents for the production of solvent-spun cellulose fibers are the so-called "ionic liquids". These solvents are described, for example, in WO 03/029329 and WO 06/108861 10. For the purposes of this patent application, the terms "solvent-spun cellulosic fiber" will be used. and "Lyocell" used synonymously.

These solvent-spun cellulose fibers have not only higher dry and non-cellulosic fibers compared to other cellulosic fibers

Wet tear strengths, but also have a special property called fibrillation. The fibrillation tendency of a single fiber can be measured, as described in WO 99/19555, for example by means of the NSF method (wet scrub resistance). This fibrillation is beneficial for a variety of applications. In other applications, fibrillation is undesirable.

In the meantime, various treatment procedures for lyocell fibers have been developed to reduce their fibrillation tendency. The result was higher NSF values. In most of these treatments, a chemical crosslinking reaction is induced by using different crosslinking substances.

Lyocell fibers are cut mainly in the form of fibers of a discrete length, i.e., 30 microns. H. as so-called "staple fibers" used. In the following, when the term "lyocell fiber" is used. is mentioned, so they are meant Lyocellfasem in the form of staple fibers. REPLACED | 2

PL0416, Lenzing AG

Cotton wool blends and lyocell fibers having a lyocell fiber content of more than 50% by weight are already commercially available. The lyocell fiber, because of its high content, determines the tear strength and elongation properties of the blend. 5

As a natural product cotton in extremely different qualities is available, the price depends on the quality. Game, which is made from 100% cotton, has very variable values in the yarn parameters. 10

It is also known from the AATCC Review, May 2002, pages 25-29, that mixing the lyocell fibers with natural colored cotton fibers could significantly improve yarn strength. It was found that the use of 20% by weight lyocell improved the yarn count of rotor hair by almost 40% and that 60% by weight lyocell increased the yarn tenacity by more than 75%. Mixing of naturally colored cotton with lyocell in needled nonwovens resulted in more than twice the strength of the nonwoven fabric, as the ball burst pressure test showed. 20

However, it became clear from this document that the improvements could be made only with the use of cotton varieties such as naturally colored cotton, which generally have poor mechanical properties. From the same document, it was also seen that in blends with a high quality white cotton the improvements achieved by blending with Lyocell are lower.

The object of this invention is to provide blends of cotton fibers and lyocell cellulase staple fibers in the form of yarns and filaments which provide both improved performance and improved performance compared to 100% cotton yarns or filaments have improved tear strength and elongation. In addition, NACHGERBCHT ~ | 3

PL0416, Lenzing AG • ································································································· It is the object of this invention to find a cost effective solution to compensate for the poor fiber properties of certain types of cotton.

The stated aims are achieved by the fact that, based on the total mixture, the content of the lyocell fibers in the mixtures of cotton and lyocell fibers is less than 50% by weight.

The content of the lyocell fibers in the yarns and threads according to the invention is preferably 25 to 33% by weight. 10

The titer of the lyocell fibers is preferably between 0.9 and 2.5 dtex, more preferably between 1.3 and 1.7 dtex.

The cut length of the Lyocell fibers is between 32 and 51 mm, 15 preferably between 34 and 38 mm.

According to the invention, the yarns and threads can be produced by means of all known production methods. An overview of these methods is in. Alfons Hofer, substances 1.1. Edition., Deutscher Fachverlag GmbH, 20 Frankfurt am Main, 1992. " to find.

In a preferred embodiment of the invention, the solvent-spun cellulose fibers are lyocell fibers with a high NSF value. Lyocell fibers with an NSF value of more than 200 are particularly preferably used.

In most applications, solvent-spun high NSF cellulosic fibers are crosslinked with an alkali-resistant crosslinking agent because the fiber blend of the invention is preferably blended with other cellulose fibers and such fibers are often exposed to alkaline baths during dyeing. For this reason, alkali-resistant crosslinking is preferred. However, cellulose fibers spun in an acid-resistant crosslinking agent basically have the same advantages in terms of

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Pill properties and can be used especially in applications where steps with acidic substances are required during the post-treatment.

Particularly suitable is an alkali-resistant crosslinking agent having the following formula (I):

X

(') wherein X is halogen, R = H or an ionic residue, n = 0 or 1, 10 Also suitable is a salt of this compound. Basically, this treatment is already known from WO 99/19555. Surprisingly, however, it has been found that the dyeability of solvent spun cellulose fiber having an NSF of greater than 200 is compatible with the dyeability of cotton, resulting in uniform dyeing results and increased dyeing efficiency.

In addition, especially when blends with synthetic fibers, i.e. 20% of the total, are used. Polyester are suitable, an acid-resistant treatment suitable, which is already known from WO 94/09191. A preferred crosslinking agent in this embodiment of the invention is 1,3,5-triacryloylhexahydro-s-triazine (THAT). In a preferred embodiment of the invention, the cellulose fibers spun from solvent are crosslinked in the as-dried state. Solvent spun fibers are referred to as "never-dried" fibers prior to first drying. It has been shown that the use of the compounds of the formula (I) has particular 5 REPLACEMENT PL0416, Lenzing AG ς :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: "

In a preferred embodiment, the 5 cotton fibers are recycled cotton fibers, i. H.

Cotton fibers that have already been made into textiles and later reprocessed by well-known methods. Such recycled cotton fibers have poor fiber properties due to the many mechanical and chemical effects to which they were subjected during their first "textile life" 10 and during the reclaiming process. As a result, the fiber length could have been reduced, for example, by cutting, abrasion, breakage or even by the degrading influence of chemicals (acids, bleaches, laundry chemicals, dyes, oxygen, sunlight, etc.). By mixing with Lyocell 15 according to the invention, such disadvantages can be compensated. The result is extremely cost-effective fiber blends that have good mechanical properties.

Another embodiment of the present invention is a product containing yarns and threads in accordance with the invention, preferably a textile article in the form of woven or knitted fabric.

Especially preferred are textile articles which mainly contain yarns and threads according to the invention. 25

The use of yarns and threads according to the invention and articles produced therefrom is a further embodiment of the invention.

Another embodiment of the present invention is a method 30 for compensating the poor fiber properties of cotton fibers. In this process, cotton fibers with poor fiber tackiness are mixed with less than 50 weight percent lyocell fibers. Following this, yarns or threads are made from this blend, the content of lyocell fibers contained in the yarns and threads being less than 50% by weight. 6

SUBSEQUENT

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In the following, the present invention will be described in more detail by way of several examples. Nevertheless, the invention is in no way limited solely to the scope of these examples: 5

Examples 1 to 6:

The yarns were made by the open-end spinning process from blends of various types of cotton and lyocell fibers as described in Table 1. The 10 improvements achieved in the yarn quality, as well as the improvements in yarn tenacity and elongation, are expressed in% and refer to a yarn (Ne 80/2) that is 100% Israel Pirna cotton in Table 1: 15

Table 1

Example 1 2 3 4 5 6 Cotton (CO) Type Israel Pirna Israel Pirna Israel Pirna Israel Pirna Cotton ELS Sudan Lyocell Type Tencel 1,3dtex, cutting length 38 mm Tencel 1,3 dtex, cutting length 38 mm Tencel 0,9 dtex, cutting length 38 Tencel 0,9 dtex, cut length 38 mm Tencel 1,4 dtex, cut length 38 mm Tencel LF 1,4 dtex, cut length 38 mm Mixing ratio cotton / lyocell (m% / m%) 75/25 75/25 75/25 67 / 33 70/30 67/33 Yarn number [N] 80/2 80/2 80/2 80/2 80/1 50% improvement: Uster CV [%] 2.8 2.8 6.7 9.8 23 , 2 10.4 thin spots [(-30%)] 23.2 18.9 78.2 158.0 54.3 65.0 thick spots [(+ 35%)] 16.1 30.0 64.6 97, 0 6367.1 87.0 Nissen [(+ 140%)] 16.6 50.6 66.9 79.8 77.9 0.0 Tensile strength [cN / tex] 4.1 5.7 9.3 9, 3 2.9 5.3 Elongation at break [%] 8.9 10.7 8.9 8.9 0.0 7.8

From the results it can be seen that yarns and threads made from blends of cotton and lyocell fibers containing less

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PL0416, Lenzing AG • · · · · · ······························································································ · When 50% by weight of lyocell fibers were produced, having both improvements in yarn properties and in tear strength and elongation.

8th

Claims (11)

········ · PL0416, Lenzing AG j | i ** .: Claims: 1. Yarns or threads of a blend of cotton and lyocell fibers, characterized in that the proportion of Lyocell fibers in the mixture is less than 50% by weight. 5 2. Game or threads according to claim 1, characterized in that the proportion of lyocell fibers in the yarns and threads is between 25 and 33% by weight. 3. Game or threads according to claim 1 or 2, characterized in that the denier of the lyocell fibers is preferably between 0.9 and 2.5 dtex, more preferably between 1.3 and 1.7 dtex. 4. Yarns or threads according to one or more of claims 1 to 3, characterized in that the cut length of the lyocell fibers is between 32 and 50 (51?) Mm, preferably 15 between 34 and 38 mm. 5. Yarns or threads according to one of the preceding claims, characterized in that the lyocell fibers are lyocell fibers whose NSF value is higher than 200. 6. Yarns or threads according to one of the preceding claims, characterized in that the cotton fibers are recycled cotton fibers. 7. textile article containing a yarn or a thread according to one or more of claims 1 to 6. 8. A textile article according to claim 6, characterized in that it consists mainly of a yarn or thread according to one or more of claims 1 to 6. 9. Use of a textile article according to claims 7 to 8 in textiles. 9 REPLACED | 5 PL0416, Lenzing AG • • • • • • • • • • • • • • • • • • • • • • • • • 10. Use of a chamois or thread according to claims 1 to 6 in textiles. 11. A method for compensating the poor fiber properties of cotton, characterized in that cotton fibers with poor fiber properties mixed with less than 50 wt .-% Lyocellfasern and then made from this mixture game or threads, which contained in the yarns and threads Content of lyocell fibers less than 50 wt .-% is. 10 REPLACED