WO1996003538A1

WO1996003538A1 - Looped fabrics made of indigo-dyed threads and/or yarns

Info

Publication number: WO1996003538A1
Application number: PCT/HU1994/000036
Authority: WO
Inventors: István HAUER; Istvánné HAUER
Original assignee: Hauer Istvan; Hauer Istvanne
Priority date: 1994-07-27
Filing date: 1994-09-09
Publication date: 1996-02-08
Also published as: HUT71693A; HU215767B; AU7706194A; HU9402211D0

Abstract

The invention relates to looped fabrics which are of a shabby bluish appearance characteristic of jeans cloth. Of the filaments which make up the looped fabrics according to the invention the basal warp is an untreated and non-dyed raw cotton thread or a cotton yarn made of two or more such threads, the loop warp is an indigo-dyed cotton thread or a cotton yarn made of two or more such threads, and the weft is a cotton yarn made of one or more untreated and non-dyed raw cotton thread(s) and one or more indigo-dyed cotton thread(s), and the product obtained by interweaving the above filaments is subjected to a finishing treatment with a cellulose decomposing enzyme.

Description

LOOPED FABRICS MADE OP INDIGO-DYED THREADS AND/OR YARNS

The invention relates to looped fabrics, particularly to terry-cloth, made of indigo-dyed threads and/or yarns.

The term "thread" as used in the specification and claims always refers to a single-stranded filament for textile weaving, whereas the term "yarn" always refers to a double- or multiple-stranded filament for textile weav¬ ing, made from two or more threads by twisting.

As known, woven cloths are made by interweaving a series of longitudinal warps with a transversal weft. When manufacturing looped fabrics or terry cloths, which form a specific class of woven textile materials, two warps of different destination are used. One of them is the basal warp which forms the basis of the textile and ensures its durable nature, whereas the other is the loop warp which ensures the characteristic nappy appearance of the product This dual warp system is interwoven with the weft in such a way that a base determining the strength, durability, stretching characte istics and dimensional stability of the product is formed from the basal warp and from the weft, and simultaneously fine surface loops characteristic of looped fabrics are formed from the loop warp on one or both sides of the product. Both threads and yarns can be used as basal warp, loop warp and weft, however, in genera at least one of the basal warp and the weft is a yarn, whereas the loop warp is generally a thread. Threads and yarns used in the manufacture of looped fabrics may be different even within one and the same product (thus e.g. basal warp, loop warp and weft may have different colours, may be made of different raw materials or may be subject¬ ed to different pre-treat ents, moreover the individual threads which build up the yarns may also be different). The so-called "jeans" cloths, made of indigo-dyed threads and/or yarns, and various overgarments and fashion articles made therefrom have been put on the market in the early sixties, and even now they are much in demand. With no regard to their origin and mode of manufacturing, all jeans cloths are of hard touch, good dimensional stability and high resistance to wear, which ensure their everlast¬ ing character. As to their appearance, a unique character¬ istic of jeans cloths is their shabby blueish colour, which can be attributed to the fact that indigo dye is missing from the woven cloth at tight, small spots or sometimes at bigger contiguous areas of irregular shape. This characteristic shabby blueish appearance can be ensured by using specific "jeans yarns" made by twisting an indigo-dyed thread with a non indigo-dyed one; it is, however, much more frequent that indigo dye is partially worn off the surface of the cloth by mechanical and/or chemical treatments, such as by scrubbing, rubbing, stone-brushing or - most frequently - by treating the cloth with a chemical capable of wearing off indigo dye ("chemical brushing agent" or "stone-brushing chemical") Most recently some enzymatic finishing agents have also been developed which enable one to reduce or omit physical or chemical brushing agents. However, these enzymatic finishing agents also decompose the materials of jeans cloth which are susceptible to the given enzyme (primarily cellulase), thus the use of such enzymes inevitably im¬ pairs the wear resistance of the cloth. To counterbalance this effect, less fine yarns and/or multiple-stranded yarns should be used in the manufacture of jeans cloth, or a part of the fibrous materials of natural origin should be replaced by enzyme-resistant synthetic fibres. All of these measures increase production costs. Although looped fabrics and methods for their manufacture are well known for a long period of time, no method has been reported before for the production of looped fabrics with a shabby blueish colour characteristic of jeans cloth, and such products have not been marketed, either.

It is well known not only to one skilled in textile industry but to non-experts, too, that the colour appearance of looped fabrics considerably differs from that of simple woven cloths (i.e. cloths made by inter- weaving a weft with a warp) made from exactly the same filaments. This fact can be attributed to the raised character of looped fabrics, i.e. to the presence of a multiplicity of fine loops on one or both of the fabric surfaces. Consequently, yarn or thread combinations which give the characte istic shabby blueish colour of jeans cloth made by simple weaving give rise to a completely different appearance in colour when used in the produc¬ tion of looped fabrics. It is also a significant differ¬ ence that the shabby blueish colour characteristic of jeans cloth appears generally only on the face of the cloth (the back side being generally blueish grey), whereas double-sided looped fabrics are the same in colour on both sides. Mechanical methods (such as brush¬ ing) applied to form the characteristic shabby blueish colour of jeans cloths are inapplicable for the treatment of looped fabrics, since they would spoil the fine sur- face loops. Further differences arise from the wear com¬ fort characteristics of jeans cloth and looped fabrics. Due to the smooth ch.arr.cter of jeans cloth, its hard touch is not disturbing and does not cause any unpleasant feel¬ ing in wear, whereas looped fabrics with jeans-hard sur- face loops are rough, scrappy, and their wear is definitely unpleasant.

It appears clearly from the above that the known methods for producing jeans cloth cannot be applied for the production of looped fabrics.. Now it has been found that when using an appropriat combination of basal warp, loop warp and wef , and by sub¬ jecting the product woven from this combination to a specific finishing treatment, looped fabrics can be pro¬ duced which, on both sides, are of a shabby blueish appear- ance characteristic of jeans cloth, their dimensional stability and resistance to wear are essentially the same as those of a jeans cloth made of identical filaments, and at the same time they do not give rise to any un¬ pleasant feeling upon wear_* Based on the above, the invention relates to looped fabrics, characterised in that of the filaments for textile production which make up the fabrics

- the basal warp is an untreated and non-dyed raw cotton thread or a cotton yarn made of two or more such threads,

- e loop warp is εr. indigo-dyed cotton thread or a cotton yarn made of two or more such threads, and

- the weft is a cotton yarn made of one or more untreat¬ ed and non-dyed raw cotton thread(s) and one or more indigo-dyed cotton thread(s), and the product obtained by interweaving the above fila¬ ments is subjected to a finishing treatment with a cellulose decomposing enzyme optionally in the presence of a chemical capable of wearing off indigo dye. The result¬ ing looped fabrics are optionally also treated with one or more other additional finishing agent (s) utilized in tex- tile industry.

The basal warp of the looped fabrics according to the invention is always a non-dyed, raw cotton thread or cotton yarn. It is preferred to use a cotton yarn as warp, since in such instances products with increased resistance to wear are obtained. The tenuity of the indi¬ vidual cotton threads which make up the cotton yarn may be the same or different. Generally it is preferred to use two cotton threads of the same tenuity to produce the cotton yarn used as basal warp. The loop warp of the looped fabrics according to the invention is always an indigo-dyed cotton thread or cotton yarn, of which it is generally preferred to use a cotton thread. If a cotton yarn is used as loop warp, it may be preferably a double-stranded yarn made by the loose twisting of two indigo-dyed cotton threads. The tenuity of the cotton thread or cotton yarn used as loop warp is preferably higher than that of the thread or yarn used as basal warp.

The weft of the looped fabrics according to the invention is always a yarn, which is made from at least one raw, non-dyed cotton thread and at least one indigo- dyed cotton thread by twisting. The tenuity of the raw, non-dyed cotton thread and that of the indigo-dyed one utilized to make the yarn may be the same or different. It is preferred to use a single raw, non-dyed cotton thread and a single indigo-dyed cotton thread to make the yarn. The tenuities of the two threads may be preferably the same; if they are different, the difference in tenuity preferably should not exceed the twofold. Optionally more than one indigo-dyed cotton threads and/or more than one raw, non-dyed cotton threads can also be applied to make the yarn to be used as weft. Such a solution may be e.g. when considerable differences in thread tenuities are counterbalanced in such a way that one thread with lower tenuity is twisted with more threads of higher tenuities. Looped fabrics are produced from the three fila¬ ment types listed above according to the usual methods of loopy weaving.

The resulting looped fabrics should by all means be subjected to a finishing treatment with a cellulose de- composing enzyme. This treatment can be performed under conditions similar to those applied in the enzymatic finish¬ ing treatment of jeans cloths. According to a preferred method, a chemical capable of wearing off indigo dye is also added to the bath for enzymatic treatment. This finish- ing treatment results in two effects. First, a part of the indigo dye is removed in small spots from the surface loops. This fact, beside the use of a specific filament combination, also contributes to the formation of a shabby blueish appearance characteristic of jeans cloth on both sides of the looped fabrics. Second, owing to the cellulose decomposing effect of the enzyme, the surface loops soften appropriately, which not only eliminates the rough, scrubby touch and unpleasant wear characteristics of the initial product, but also grants . definitely pleasant wear characte istics to the finished product. At the same time, the finishing treatment with a cellulose decomposing enzyme does not impair the strength and wear resistance character¬ istics of the initial product, thus no counterbalancing measures should be taken which were necessary when subject- ing a jeans cloth to enzymatic finishing. The reason why the cellulose decomposing enzyme acts only or at least in overwhelming part on the surface loops is not yet known; presumably it can be traced back to specific phenomena which take place on the boundary surfaces. The enzymatic finishing treatment is performed at a temperature and pH falling within the operating range of the cellulose decomposing enzyme present. Thus e.g. when endo-glucanase is utilized as cellulose decomposing enzyme, the finishing treatment may be performed at a pH of 4.5-7.0 and at a temperature of 40-55°C. The time of enzymatic finishing treatment varies with the activity of the enzyme and with other conditions of the treatment (temperature, enzyme concentration, type of treatment, type and amount of additives present, etc.), but it takes generally 10-90 minutes, preferably 30-75 minutes. It is preferred to per¬ form enzymatic finishing treatment in the presence of a chemical capable of wearing off indigo dye, since it assists the enzyme to reach the indigo-dyed cotton fibres. It is obvious for one skilled in the art that any added chemical brushing agent must be compatible with the enzyme present.

Enzymatic finishing treatment may be performed e.g. in such a way that the looped fabrics are immersed into a bath of appropriate temperature and pH, containing the enzyme and preferably the chemical brushing agent, too. A low concentration (some tenth or hundredth percent, generally 0.1-0.3 % by weight) of enzyme is generally sufficient; the amount of chemical brushing agent is generally even lower than that of the enzyme.

At the end of the enzymatic finishing treatment the enzyme present is inactivated. The simplest way of inactivation is heat treatment, which can be performed e.g. by heating the enzyme-containing bath to an appropriately high temperature to inactivate the enzyme, or by remov¬ ing the wet looped fabrics from the bath and treating them with hot air. The temperature of heat treatment de¬ pends on the type of the enzyme present, but it is generally higher than 6θ°C.

The appearance of the resulting looped fabrics is, on both sides, shabby blueish, characteristic of jeans cloth. As a result of the enzymatic finishing treatment the stiftness of the surface loops decreases considerably, the touch of the product is no more rough, and the product does not have any unpleasant wear characteristic. If looped fabrics fitting specific requirements should be produced, the products prepared as disclosed above can also be subjected to one or more appropriate other finishing operation(s) utilized in textile industry, Thus e.g. when soft and highly water-absorbing towels should be made from the looped fabrics, the appropriate finishing operations are also performed.

Claims

What we claim is:

Looped fabrics, characterised in that of the filaments for textile production which make up the fabrics

- the loop warp is an indigo-dyed cotton thread or a cotton yarn made of two or more such threads, and

- the weft is a cotton yarn made of one or more untreat- ed and non-dyed raw cotton thread(s) and one or more indigo-dyed cotton thread(s), and the product obtained by interweaving the above fila¬ ments is subjected to a finishing treatment with a cellulose decomposing enzyme.