JP2009007680A - Denim fabric and method for preventing discoloration of the fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a denim fabric (vat dyed fabric) which is little discolored (changes the color), when washed. <P>SOLUTION: The method for preventing the discoloration of the denim fabric includes dyeing yarns or a fabric containing cellulose fibers, treating the dyed yarns or fabric with liquid ammonia, processing the treated yarns or fabric with a resin to cross-link the cellulose fibers, and then washing the yarns or the fabric with hot water. In the denim fabric, frictional fastness is ≥4.0 grade in a dry state (warps) and 1 to 2 grade in a wet state (warps); washing fastness is ≥4 grade in a color-faded state and 3 to 4 grade in a stained state; and the L*value of the surface color is ≤30. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to prevention of discoloration peculiar to vat dyeing (indigo dyeing) of denim fabrics.

Indigo dyeing is a typical dyeing method for denim fabrics.
Since the indigo dye becomes water-soluble by reduction, when the cellulose fiber is immersed in the dyeing solution in this state, the dye moves with the water into the cellulose fiber so that the difference in concentration of the dye in the fiber and in the fiber is the same. Thereafter, when the cellulose fiber is exposed to air, the indigo dye is oxidized by oxygen in the air and regenerates a pigment that is hardly soluble in water in the cellulose fiber. By repeating these steps, a deep color characteristic of denim fabric can be obtained.
The binding force between the cellulose fiber and the dye is said to be an intermolecular force or a hydrogen bonding force, and is considered to be fixed to the amorphous region of the cellulose fiber by these forces. There is also a form in which a part is attached to the cellulose fiber surface. These dyeing mechanisms are very similar to those of direct dyes. However, the molecular weight of the direct dye is larger than that of indigo and the dye is dyed at a high temperature.

  Indigo dyes are not chemically bonded to cellulose fibers, and because the dye molecules are small, when they are washed with water or hot water, especially hot water, the molecular movement of the cellulose fibers becomes active, and the dye is again in the water. Elute. This phenomenon becomes prominent with the use of detergents.

Taking advantage of the features of indigo dyeing, denim fabrics that have been individually processed using stone wash processing or bleach have been accepted.
However, the elution of the dye causes a decrease in dyeing fastness. In fact, the dark denim fabric whose L * value on the fabric surface exceeds 30 is contaminated by washing, discoloration, contamination by friction, etc. It has become a big problem.

  Patent Document 1 (Japanese Laid-Open Patent Publication No. 11-335935) discloses a denim fabric that uses indigo dyeing on a denim fabric made by blending a pre-dyed synthetic fiber and cotton fiber, and uses a color fading peculiar to indigo dyeing. Woven and knitted fabrics are described.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2005-42267) describes a method for processing a denim fabric that has a dry and soft natural texture and a light feeling, is less likely to wrinkle, and has a flat appearance. ing. In this patent document 2, as a prior art,
“(1) Resin processing: By applying a form-stable resin processing to denim, the fabric is prevented from shrinking, thereby preventing wrinkles after washing and the disappearance of twill lines”.
(2) mercerization (alkali treatment, mercerization): The fabric is soaked in a caustic soda solution and the cotton fibers swell and shrink. To increase.
(3) Liquid ammonia treatment (liquid ammonia mercerization): The fabric is dipped in liquid ammonia to swell the cotton fibers, and then pulled in the vertical direction to increase the arrangement of the warp cotton fibers. "
Etc. are described.

  Patent Documents 1 and 2 also describe how to discolor indigo dyeing, but do not describe how to eliminate or reduce discoloration.

JP 11-335935 A JP 2005-42267 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to make a denim fabric (a vat dyed fabric) with less color dropout (change) during washing.

The present invention
<1> Denim characterized in that the L * value of the surface color is 30 or less and the fastness to friction is 4.0 grade or higher for dryness (vertical) and 1-2 grade for wet (vertical) Cloth,
<2> Denim fabric characterized by fastness to washing, color change of 4 or higher, and contamination of 3 or 4 or higher. <3> L * value of fabric surface color for yarn or fabric containing cellulose fiber And dyeing the dyed thread or fabric with liquid ammonia, then cross-linking the cellulose fibers with a resin processing agent, and then washing the thread or fabric with hot water. Denim fabric color fading prevention processing method, characterized by
<4> The resin processing agent reacts with cellulose to form a crosslink, and has two or more groups that bind to cellulose such as dihydroxyethylene urea derivatives, melamine derivatives, ethylene urea derivatives, epoxy derivatives, carboxylic acid derivatives, and the like. <2> The method for preventing discoloration of denim fabric according to <2>, which is selected from compounds
I will provide a.

  According to the processing method of the present invention, an improvement in dyeing fastness that could not be obtained in the past can be obtained, and a dimensional stability of the denim fabric, a soft texture, a flat fabric surface, and a denim fabric that is difficult to wrinkle can be obtained.

The present invention is described in detail below.
(1) Dyeing In order to dye yarn or fabric, dyeing is repeated several times by immersing in a dyeing bath containing a dyeing solution such as indigo dye, drawing out from the dyeing bath, and oxidizing in air. And let it dry. As long as the L * value of the surface color on the fabric is 30 or less, the dyeing solution may be a sulfur dye (for example, ASATHIO Brilliant Blue BO or ASATHIO Brown GRN (both manufactured by Asahi Chemical Industry Co., Ltd.). ) Etc.) can also be used.
The dye concentration, dipping time, and air oxidation time are not particularly limited as long as the L * value of the surface color on the fabric is 30 or less. In this case, the dye concentration is preferably 0.8 g / L or more, particularly preferably 1.0 g / L or more. The immersion time is preferably 15 to 120 seconds, particularly preferably 20 to 90 seconds, and the air oxidation is preferably performed for 60 to 300 seconds, particularly 90 to 270 seconds. Further, the number of repetitions of immersion and air oxidation is the same, and 3 to 8 times are preferable. When the above conditions are exceeded, only a light color is dyed, and there is a problem that a deep dark color unique to denim fabric cannot be obtained, or the process becomes long.

(2) Liquid ammonia treatment First, when cellulose fiber yarn or fabric dyed with a vat dye is treated with liquid ammonia, the cellulose fibers swell once, but then the average size of the pores in the non-crystalline region of cellulose becomes small. . Therefore, the dye once dyed on the non-crystalline region of the cellulose fiber is not easily removed by washing. This liquid ammonia treatment may be performed at any position after dyeing. However, if this treatment is performed after resin processing, the effect of resin processing is lost.

The liquid ammonia treatment can be carried out, for example, by impregnating the cellulose fiber-containing structure with liquid ammonia maintained at a normal pressure and at a temperature of −33 ° C. or lower. As the impregnation method, a method of spraying or coating liquid ammonia can be used. In this case, the liquid ammonia impregnation time is appropriately selected, but usually about 5 to 40 seconds is preferable.
In addition, although liquid ammonia is most commonly used for liquid ammonia treatment, lower alkylamines such as methylamine and ethylamine can also be used in some cases.
The cellulose fiber-containing structure treated with liquid ammonia removes the attached ammonia by heating.

(3) Resin Processing Next, a resin processing is performed in which the cellulose fiber yarn or fabric treated with liquid ammonia is reacted with a hydroxyl group of cellulose to generate a cross-linking bond between the fibers.
Any resin finishing agent may be used as long as it reacts with the hydroxyl group of cellulose to form a crosslink. Examples of such compounds include dihydroxyethyleneurea derivatives, melamine derivatives, ethyleneurea derivatives, epoxy derivatives, carboxylic acid derivatives, compounds having two or more of these reactive groups, or mixtures thereof. For example, glyoxal, glutaraldehyde Aldehydes such as diglycidyl ether, polycarboxylic acids such as tetrabutanecarboxylic acid, dimethylol urea, trimethylolmelamine, dimethylolethyleneurea, fibrin-reactive N-methylol compounds such as dimethyloldihydroxyethyleneurea Among them, among them, a fibrin-reactive N-methylol compound, a glyoxal resin, and the like are preferable.

  The addition amount to a resin processing agent is 3.0-9.0 mass% with respect to the weight of the cellulose fiber containing structure which performs resin processing, Preferably it is 3.6-7.8 mass%. If the addition amount is less than 3.0% by mass, the effect as the resin processing may not be sufficiently exhibited, and if it exceeds 9.0% by mass, the strength reduction accompanying the resin processing becomes remarkable.

  In the resin processing of the present invention, a catalyst can be added in order to increase the reactivity between the resin processing agent and cellulose and to perform the resin processing quickly. The catalyst is not particularly limited as long as it is a catalyst usually used for resin processing. For example, borofluorinated compounds such as ammonium borofluoride, sodium borofluoride, potassium borofluoride, zinc borofluoride, and magnesium chloride. And neutral metal salt catalysts such as magnesium sulfate and magnesium nitrate, and inorganic acids such as phosphoric acid, hydrochloric acid, sulfuric acid, sulfurous acid, hyposulfite and boric acid. These catalysts may be used in combination with organic acids such as citric acid, tartaric acid, apple acid and maleic acid as a co-catalyst, if necessary.

Moreover, the auxiliary | assistant for advancing reaction of a cellulose and resin smoothly can be added to a resin processing agent as needed. The auxiliary agent has an action as a reaction solvent that promotes the reaction between the resin processing agent and cellulose, or promotes the reaction even in the cross-linking reaction, and further has an action of swelling the cellulose.
Examples of the auxiliary agent include polyhydric alcohols such as glycerin, ethylene glycol, polyethylene glycol, and polypropylene glycol, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diethylene glycol monobutyl ether. Nitrogen-containing solvents such as ether alcohols, dimethylformamide, morpholine, 2-pyrrolidone, dimethylacetamide, N-methylpyrrolidone, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl acetate Examples include esters such as ether and γ-butyrolactone.

  In addition to the above-mentioned chemicals, a softening agent for adjusting the texture, a formalin catcher for reducing free formalin concentration, and the like can be added to the resin processing agent of the present invention as necessary.

(4) Hot water washing In this invention, the dye adhering to the surface side of a cellulose fiber is washed off by hot water washing after resin processing. The dye dyed in the pores in the non-crystalline region of cellulose is difficult to be removed, but the dye adhering to the cellulose surface side is removed in advance with hot water in order to easily fall off. It is most effective to perform hot water washing at 60 to 65 ° C. for 0.5 to 2 minutes. Above 65 ° C., there is a problem of dropping off the dye, and when the time exceeds 2 minutes, the efficiency is deteriorated.

  In the present invention, a cellulose fiber-containing yarn or fabric dyed with a vat dye (indigo dye) is subjected to liquid ammonia treatment to reduce the pores in the non-crystalline region of the cellulose fiber, and further subjected to resin processing to obtain a cellulose fiber. A cross-linking bond is formed between them, making it difficult to dissolve vat dyes. The easy-to-drop dye attached to the surface side of the cellulose fiber is removed by washing with hot water after resin processing.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited to the following Example.

[Example 1]
(1) Dyeing The yarn was dyed by repeating it eight times by dipping the yarn in a dyeing solution of 1.6 g / L of indigo dye for 30 seconds and oxidizing it with air.
(2) Weaving Using the dyed yarn, the warp is a single yarn of cotton count 7 and the weft is a single yarn of cotton count 10, with a density of 67 warps / 吋 and 52 wefts / 吋, 3/1 Weaved with twill.
(3) Hot water washing The surface of the fabric was baked twice and then passed through hot water at a temperature of 40 m / min through hot water at a temperature of 40 ° C.
(4) Liquid Ammonia Processing The woven fabric was impregnated with liquid ammonia maintained at a normal pressure and a temperature of −33 ° C. or lower for 5 to 40 seconds.

(5) Resin processing The following processing agent was immersed in the fabric, followed by drying and heat treatment.
The following blending ratio (%) is mass% in 100 mass% of the processing agent (aqueous solution).

(6) Hot water washing The woven fabric was passed through hot water at a temperature of 60 to 65 ° C. at a feed rate of 45 m / min.
The denim fabric which passed through the processing process of said (1)-(6) was produced.
(7) Measurement, evaluation Friction fastness test: JIS L 0849 (Type II testing machine)
Washing fastness test: JIS L 0844 A-2 Color measurement: L *, a *, b * surface system on the fabric surface was measured with a spectrocolorimeter (CE-7000A, manufactured by Gretag Macbeth). .
The above test was conducted and the results are shown in Table 2.

[Comparative Example 1]
In the same manner as in Example 1, (1) dyeing, (2) weaving, (3) hot water washed denim fabric was prepared, and (7) measurement was performed. The results are shown in Table 2.

[Comparative Example 2]
In the same manner as in Example 1, (1) dyeing, (2) weaving, (3) hot water washing, (5) resin processing, (6) hot water washed denim fabric was prepared, and (7) measurement was performed. The results are shown in Table 2.

[Comparative Example 3]
Similarly to Example 1, (1) dyeing, (2) weaving, (3) hot water washing, (4) liquid ammonia processing, (6) hot water washed denim fabric was prepared, and (7) measurement was performed. The results are shown in Table 2.

[Comparative Example 4]
The indigo dye of Example 1 was immersed in a 0.6 g / L dyeing solution for 30 seconds and air-oxidized twice, except that it was dyed twice (1) dyeing, (2) weaving, (3) Denim fabric washed with hot water was prepared, and (7) measurement was performed. The results are shown in Table 2.

原布・・・・それぞれの加工揚り織物
ＷＡ洗い・・それぞれの原布を常温で１０分洗い、タンブル乾燥機で乾燥した織物
比較例４は、インジゴ濃度及び浸漬、空気酸化の繰り返し回数を少なくすることで、摩擦堅牢度、洗濯堅牢度とも、良好な結果であったが、デニム特有の深みのある濃紺の色合いが得られず、薄い水色の生地であった。（L*値が３０を超えている。）

Raw fabric ... ・ While each processed fried fabric WA washed ・ ・ Fabric obtained by washing each raw fabric for 10 minutes at room temperature and drying with a tumble dryer Comparative Example 4 shows the indigo concentration and the number of repetitions of immersion and air oxidation. By reducing it, both the fastness to rubbing and the fastness to washing were good results, but the deep dark blue color peculiar to denim was not obtained, and the fabric was light blue. (L * value is over 30.)

Next, the texture (texture softness) of the fabric obtained above, the degree of color fading after washing with WA and after 10 home washings were evaluated by the following methods. The results are shown in Table 3.
Texture evaluation Using the base fabric and the fabric of Comparative Example 1 after washing with WA as a standard (3 points), a 5-point evaluation was performed from 1 point (hard) to 5 points (soft).
Color fading evaluation After the WA washing of Comparative Example 1 and the fabric color after 10 washings, the standard (3 points) was used to perform a five-step evaluation from 1 point (light color) to 5 points (dark color). Laundry method Vertical 70 cm × A sample of a 70 cm wide fabric with a vertical cross section cut into a cylindrical shape by sewing with a lock sewing machine is placed in a bath (together with a fully automatic washing machine for home use with the fabric surface facing the outside of the cylinder). 1) each, and after washing, rinsing and dehydration 10 times on a standard course, drying was performed. In addition, 20 g of household detergent tops (manufactured by LION Co., Ltd.) were added for each washing.

比較例２は樹脂加工を行っているので、生地の風合いが硬くなっているが、実施例１は、液体アンモニア加工後に樹脂加工しているので、比較例２に比べて柔らかく、比較例１の後加工なしの生地と同等の風合いの生地が得られた。
また、実施例１は液体アンモニア加工を実施しているので、皺になりにくく、フラットな表面が得られ、さらに、樹脂加工も施しているので、洗いによる色落ちが抑制され、ＷＡ洗い後で最も濃色の生地が得られた。更に、洗濯を繰り返しても色落ちが遅く、最も濃色の生地が得られた。

Since Comparative Example 2 performs resin processing, the texture of the dough is hard, but since Example 1 is resin processed after liquid ammonia processing, it is softer than Comparative Example 2, A fabric having a texture equivalent to that of the fabric without post-processing was obtained.
Moreover, since Example 1 is performing liquid ammonia processing, it is hard to become wrinkles, a flat surface is obtained, and furthermore, since resin processing is also performed, discoloration due to washing is suppressed, and after WA washing The darkest dough was obtained. Furthermore, the color fading was slow even after repeated washing, and the darkest fabric was obtained.

Claims (4)

  A denim fabric having a surface color L * value of 30 or less and a fastness to friction of 4th grade or higher for dry (vertical) and 1st or higher for wet (vertical).   Denim fabric characterized by a fastness to washing, a discoloration of grade 4 or higher, and a contamination level of grade 3-4 or higher.   A yarn or fabric containing cellulose fiber is dyed so that the L * value of the fabric surface color is 30 or less, the dyed yarn or fabric is treated with liquid ammonia, and then the cellulose fiber is treated with a resin processing agent. A method for preventing discoloration of denim fabric, wherein the yarn or fabric is washed with hot water after being crosslinked.   The resin processing agent reacts with cellulose to form a crosslink, and is selected from compounds having two or more groups that bind to cellulose, such as dihydroxyethylene urea derivatives, melamine derivatives, ethylene urea derivatives, epoxy derivatives, carboxylic acid derivatives, and the like. The method for preventing discoloration of denim fabric according to claim 3.