Fiber structure dyeing method

Abstract

To provide a dyeing method for dyeing a woven or knitted fabric containing at least cotton with a disperse dye, capable of achieving a high-durability fiber structure through uniform and deep coloration.SOLUTION: As pretreatment steps for dyeing, an epoxy resin treatment step for treating a woven or knitted fabric containing at least cotton with an epoxy resin and a benzoylation step for benzoylating the epoxy resin-treated woven or knitted fabric are provided. The benzoylated woven or knitted fabric has a benzoyl substitution degree of 10%-20%, as determined by the dropwise technique. The dyeing method is preferably anhydrous dyeing using supercritical carbon dioxide as the medium.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a dyeing method for dyeing a woven or knitted fabric containing at least cotton with a disperse dye, which can dye a fiber structure uniformly and in a deep color and has high fastness. [Background technology]

[0002] Conventionally, cellulosic fibers have generally been dyed using direct or reactive dyes with a large liquor ratio, but dyeing with disperse dyes is preferred from the standpoint of color vividness and fastness.

[0003] Although disperse dyes do not exhibit dyeing properties for cellulose fibers, cellulose fibers are modified and dyed with disperse dyes in the same manner as synthetic fibers such as polyester fibers and polyamide fibers. Specifically, aromatic acyl groups such as benzoyl groups, which are hydrophobic groups, are introduced into the cellulose molecules in the cellulose fibers, and then the fibers are dyed with disperse dyes.

[0004] Patent Document 1 describes a method for benzoylating cellulose fibers, which is characterized by impregnating cellulose fibers with benzoyl chloride and then immersing the fibers in an aqueous solution containing 10% by weight or more of an alkali hydroxide.

[0005] According to this method, it is possible to impart to the cellulose fibers the property of being dyed with a disperse dye, but there is a problem in that uneven dyeing occurs and uniform dyeing cannot be achieved.

[0006] On the other hand, conventional dyeing methods using direct dyes have problems such as waste liquid treatment after dyeing and the need for large amounts of water for dyeing, and are considered to have a large environmental impact. In this context, there is a demand for dyeing methods that conserve resources such as water and reduce the environmental impact.

[0007] As a dyeing method with a small environmental impact, an anhydrous dyeing method using supercritical carbon dioxide has been proposed as in Patent Document 2. In this anhydrous dyeing method, polyester fibers are dyed using a disperse dye that is soluble in carbon dioxide fluid in a supercritical state.

[0008] In order to apply such an anhydrous dyeing method using disperse dyes to cellulosic fibers, a dyeing method that can dye cellulosic fibers uniformly without causing uneven dyeing even when disperse dyes are used for dyeing cellulosic fibers is desired. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 51-149981 [Patent Document 2] JP 2001-32134 A Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a method for dyeing a woven or knitted fabric containing at least cotton with a disperse dye, which can dye a fiber structure uniformly and in a deep color and has high fastness. [Means for solving the problem]

[0011] As a result of intensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by providing, as a pre-step of the dyeing step, an epoxy resin treatment step of treating the woven or knitted fabric with an epoxy resin, and a benzoylation step of benzoylating the epoxy resin-treated woven or knitted fabric, in a dyeing method in which a woven or knitted fabric containing at least cotton is dyed with a disperse dye, and have thus completed the present invention.

[0012] The present invention relates to a method for dyeing a woven or knitted fabric containing at least cotton with a disperse dye, and is based on the following techniques.

[0013] (1) A dyeing method for dyeing a woven or knitted fabric containing at least cotton with a disperse dye, comprising an epoxy resin treatment step of treating the woven or knitted fabric with an epoxy resin prior to the dyeing step, and a benzoylation step of benzoylating the epoxy resin-treated woven or knitted fabric.

[0014] (2) The dyeing method according to (1), wherein the woven or knitted fabric subjected to the benzoylation treatment in the benzoylation step has a degree of benzoyl substitution of 10% to 20% as determined by a dropping method.

[0015] (3) The dyeing method according to (1) or (2), wherein the woven or knitted fabric is made of 100% cotton or a blended woven or knitted fabric of cotton and polyester.

[0016] (4) The dyeing method according to any one of (1) to (3), wherein the dyeing method is anhydrous dyeing using supercritical carbon dioxide as a medium.

[0017] (5) Textile products dyed by any of the dyeing methods listed in (1) to (4). Effect of the Invention

[0018] According to the present invention, there is provided a method for dyeing a woven or knitted fabric containing at least cotton with a disperse dye, which can dye the fabric uniformly and deeply and has high fastness to a fiber structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention relates to a dyeing method for dyeing a woven or knitted fabric containing at least cotton with a disperse dye, and includes an epoxy resin treatment step of treating the woven or knitted fabric with an epoxy resin as a pre-dyeing step, and a benzoylation step of benzoylating the epoxy resin-treated woven or knitted fabric.

[0020] <Epoxy resin treatment process> A woven or knitted fabric containing at least cotton is crosslinked with an epoxy resin by the aid of a catalyst. Specifically, a treatment liquid containing an epoxy resin, a catalyst, and a penetrant is prepared, and the woven or knitted fabric containing at least cotton is immersed in the treatment liquid, squeezed with a mangle, and then dried.Then, the fabric is baked at a high temperature, washed with water, and dried to complete the epoxy resin treatment.

[0021] The catalyst may be a metal fluoroborate such as zinc fluoroborate, magnesium fluoroborate, or sodium fluoroborate, and these may be used alone or in combination of two or more kinds.

[0022] By treating woven or knitted fabrics containing at least cotton with epoxy resin, the woven or knitted fabrics are made hydrophobic. The benzoyl group contained in the epoxy resin interacts with the chemicals used in benzoylation, making the benzoylation easier to proceed. This allows the amount of chemicals used in benzoylation to be reduced and benzoylation to be carried out more efficiently. In addition, the interaction with the disperse dyes used in the dyeing process is also enhanced, increasing the compatibility between the modified fabric and the dye, and improving dyeability.

[0023] <Benzoylation process> An alkaline aqueous solution is applied to the epoxy resin-treated woven or knitted fabric to convert the cotton contained in the woven or knitted fabric into alkaline cellulose, and then the water is removed.

[0024] As the alkaline aqueous solution, a sodium hydroxide (caustic soda) aqueous solution, a potassium hydroxide aqueous solution, a lithium hydroxide aqueous solution, a sodium carbonate aqueous solution, a sodium bicarbonate aqueous solution, etc. can be used, and as a method for applying the alkaline aqueous solution to the woven or knitted fabric, a conventionally known method such as a dipping method or a spraying method can be used.

[0025] A non-aqueous solution containing benzoic anhydride is applied to the woven or knitted fabric from which the aqueous alkali solution has been applied and water has been removed. As a method for applying benzoic anhydride, a conventionally known method such as a dipping method or a spraying method can be used.

[0026] By adding cold water or room temperature water to the woven or knitted fabric after adding benzoic anhydride, the benzoylation reaction proceeds more easily and uniformly due to the high reactivity of the alkali cellulose. The method for adding cold water or room temperature water can be a water immersion method in which the fabric is immersed in water or a water spray method in which water is sprayed.

[0027] By the above-mentioned method, the cellulose fibers contained in the woven or knitted fabric are benzoylated. After the woven or knitted fabric is benzoylated, it is washed with hot water or the like and dried in the usual manner.

[0028] The degree of benzoyl substitution of the woven or knitted fabric benzoylated in the above benzoylation step, as determined by the dropping method, is 10% to 20%, and preferably 15% to 20%. By setting the degree of benzoyl substitution within the above range, good deep dyeability and high fastness with little dye unevenness can be obtained.

[0029] In the present invention, the degree of benzoyl substitution is determined by the dropping method. The specific method of the dropping method is as follows.

[0030] <Drop method> To quantify the amount of benzoyl groups in cotton woven and knitted fabrics, a method was used that applied the customs analytical method "Analysis of starch derivatives." Acetylated cotton woven and knitted fabrics were stirred under high alkali conditions. The degree of substitution was calculated by titrating the benzoyl groups in the solution that were released under excessively basic conditions with hydrochloric acid using phenolphthalein as an indicator. In addition, the benzoylation reaction is assumed to occur only in the non-crystalline parts of the cellulose, and the amount of non-crystalline regions was calibrated for mercerized and liquid ammonia treated fabrics. The calculation formula is as follows:

[0031] DS value = 162 / (10500-106A) A=(V0-V)×F×N×0.105×100 / m Benzoyl substitution degree = DS value / 3 x 100

[0032] DS value: The number of substituted -OH groups in one glucose molecule A: Benzoyl group content (%) V0: Blank drop volume V: Amount of sample dropped F: Factor N: Normality m: Weight of fabric when completely dry

[0033] <Staining method> As the dyeing method, a known dyeing method using a disperse dye can be used. For example, the dyeing is performed in a dye solution prepared by adjusting the disperse dye with dyeing auxiliaries and pH adjusters under the conditions of a liquor ratio of 1:40 to 1:60, a temperature of 130°C to 150°C, and a time of 45 to 60 minutes.

[0034] In the present invention, an anhydrous dyeing method using a disperse dye with supercritical carbon dioxide as a dyeing medium can also be adopted. In the anhydrous dyeing, for example, a disperse dye and a benzoyl-treated woven or knitted fabric are placed in an autoclave, dry ice or liquid carbon dioxide is added therein, and the autoclave is sealed, pressurized and heated to maintain a pressure of 7.38 MPa or more and a temperature of 31.1°C or more, thereby dyeing in a supercritical state.

[0035] After the dyeing is completed, that is, after dyeing with a supercritical carbon dioxide medium is completed, the temperature and pressure are returned to below the critical point, and the dye that is not absorbed into the dyed material becomes powdered and is separated from the carbon dioxide. This makes it possible to reuse both the dye and the carbon dioxide. Unlike in the case of aqueous dyeing, the dye remains in the residual liquid after dyeing, and there is no need for wastewater treatment, thereby reducing the environmental impact.

[0036] <Disperse dye> As the disperse dye, benzene azo type (monoazo, disazo, etc.), heterocyclic azo type (thiazole azo, benzothiazole azo, quinoline azo, pyridine azo, imidazole azo, thiophene azo, etc.), anthraquinone type, condensation type (quinophthaline, styryl, coumarin, etc.), etc. can be used, and these can be used alone or in combination. EXAMPLES

[0037] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0038] <Examples 1 to 4, Comparative Example 1> A 100% cotton fabric (100% cotton plain weave fabric (mercerized and liquid ammonia processed) 38cm x 100cm) was immersed in an epoxy resin treatment solution containing 20% ​​by weight of hydrophilic epoxy resin, 1.76% of 45% concentration zinc borofluoride, and a penetrant by padding, squeezed with a mangle, and dried with a tenter. The epoxy treatment was then completed by baking at 140℃ for 2 minutes, rinsing with water, and drying.

[0039] An aqueous solution of sodium hydroxide was applied to the epoxy resin-treated woven fabric by immersion to convert the cotton contained in the woven or knitted fabric into alkali cellulose, and the water was then removed by squeezing with a mangle.

[0040] A mixture of benzoic anhydride, acetone, and water was applied by immersion under the conditions shown in Table 1 to the woven fabric to which the alkaline aqueous solution was applied and from which the moisture was removed.

[0041] The fabric was reacted in an acetone solution of benzoic anhydride at 55° C. for 2 hours, and then water at room temperature was added thereto by a water immersion method, followed by washing with hot water and drying.

[0042] The degree of benzoyl substitution (%) of the woven fabric benzoylated in the above benzoylation step was determined by the dropping method. The degree of benzoyl substitution (%) is shown in Table 1.

[0043] The fabrics of Examples 1 to 4 and Comparative Examples 1 and 2 and a disperse dye (Sumikaron Red E-FBL (manufactured by Sumika Chemtex Corporation)) at 1.0% owf were placed in a supercritical fluid treatment device, which was then filled with liquefied carbon dioxide gas and subjected to a dyeing process under conditions of 120°C, 25 MPa, and 30 minutes.

[0044] The dyed textile products were evaluated for dye uniformity, dye strength, and washing fastness.

[0045] <Uniformity of dyeing> The scale was 1 to 5, with 1 being the most uneven dyeing and 5 being the least uneven dyeing. In addition, in the evaluation of the uniformity of the dyeing, the evaluation of the unevenness of the dyeing when polyester fabric was dyed with disperse dyes was set to 5, and this was used as the standard. In addition, when the dyeability was extremely poor, it was not possible to evaluate it.

[0046] <Staining density> The fabric was measured using a Konica Minolta colorimeter (CM3600A) to determine the total density (K / S). Total concentration: K / S=(1-R2) / 2S K: Light absorption coefficient S: Light scattering coefficient R: Surface scattering rate of light

[0047] <Washing fastness> The degree of discoloration (discoloration) of the test pieces and the degree of staining (cotton staining, polyester staining, liquid staining) of the attached white cloth were judged according to the A-2 method of JIS L 0844 "Test method for color fastness to washing".

[0048] The evaluation results of dye uniformity, dye depth and washing fastness are shown in Table 1.

[0049] [Table 1]

[0050] As can be seen from Table 1, the dyeing method of the present invention obtained good evaluation results in terms of dye uniformity, dye depth, and washing fastness. [Industrial Applicability]

[0051] According to the dyeing method of the present invention, even when woven or knitted fabrics containing at least cotton are dyed with disperse dyes, it is possible to provide fiber structures that are dyed uniformly and deeply and have high fastness, and thus the method is of extremely high practical value.

Claims

1. A dyeing method for dyeing a woven or knitted fabric containing at least cotton with a disperse dye, comprising an epoxy resin treatment step of treating the woven or knitted fabric with an epoxy resin as a pre-dyeing step, and a benzoylation step of benzoylating the epoxy resin-treated woven or knitted fabric.

2. 2. The method according to claim 1, wherein the woven or knitted fabric subjected to the benzoylation treatment in the benzoylation step has a degree of benzoyl substitution of 10% to 20% as determined by a dropping method.

3. 3. The method according to claim 1, wherein the woven or knitted fabric is a woven or knitted fabric made of 100% cotton or a blended woven or knitted fabric of cotton and polyester.

4. 4. The dyeing method according to claim 1, wherein the dyeing method is anhydrous dyeing using supercritical carbon dioxide as a medium.

5. A textile product dyed by the dyeing method according to any one of claims 1 to 4.

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