Method for producing cellulose-based difficult-to-dye fibers and method for producing melange-tone fiber fabric

Abstract

To provide a method for producing a cellulosic hard-to-dye fiber that can prepare a melange-tone fiber fabric without water repellent treatment.SOLUTION: According to one embodiment, a method for producing a cellulosic hard-to-dye fiber includes: a graft step in which a cellulosic fiber is grafted with a carboxyl group-containing compound with an ethylenic unsaturated double bond, to introduce the carboxyl group; and a dehydration condensation step for subjecting the carboxyl group-introduced cellulosic fiber to dehydration and condensation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing cellulose-based difficult-to-dye fibers and a method for producing melange-tone fiber fabrics.

Background Art

[0002] Conventionally, non-uniform dyed products such as mottled, tie-dyed, patterned, frost-like tones (hereinafter referred to as "melange-tone fiber fabrics") have been demanded by users as fiber fabrics with high added value. Usually, a so-called "post-dyeing" method has been proposed in which a fiber fabric woven by combining different materials is dyed by utilizing the difference in dyeability of the materials and adding one or more dyes. In fabrics such as knitted or woven fabrics combined with polyester, nylon, acrylic, wool, silk, cotton, hemp, rayon, etc., the dyes that can be used for dyeing also differ depending on the type of fiber, and melange-tone fiber fabrics can be obtained. In addition, when expressing multi-color patterns using the same material, a so-called "pre-dyeing" method is used in which the spun yarn is dyed into the desired hue and then a plurality of dyed yarns are combined and woven.

[0003] In recent years, natural fibers have been re-evaluated from the perspective of the transition to a sustainable society. Therefore, there is a demand for melange-tone fiber fabrics by a post-dyeing method mainly using, for example, cotton materials which are the main fibers of natural fibers. For example, the applicant of the present application has proposed in Patent Document 1 a method of obtaining a non-uniform dyed product by fixing a water-repellent agent to cotton, a fiber bundle or a filamentous cellulose fiber aggregate, producing a fabric together with an unfixed cellulose fiber aggregate, and subjecting the fabric to piece dyeing (post-dyeing). By this method, for example, a mottled denim-like fabric excellent in aesthetics can be obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above prior art has a problem that a water-repellent treatment using a water-repellent agent is essential, and the water absorbency of the cellulose-based fiber decreases.

[0006] In order to solve the above prior problems, the present invention provides a method for producing a cellulose-based fiber with poor dyeability that can produce a mélange fiber fabric without a water-repellent treatment. The present invention also provides a method for producing a mélange fiber fabric containing the cellulose-based fiber with poor dyeability.

Means for Solving the Problems

[0007] In one aspect, the present invention is a method for producing a cellulose-based fiber with poor dyeability, a grafting step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto a cellulose-based fiber to introduce a carboxyl group, and a dehydration condensation step of dehydrating and condensing the cellulose-based fiber into which the carboxyl group has been introduced, and relates to a method for producing a cellulose-based fiber with poor dyeability.

[0008] In one aspect, the present invention is a method for producing a mélange fiber fabric, a spinning step of producing a spun yarn (A1) containing a cellulose-based fiber with poor dyeability produced by the production method of the present invention, a step of preparing a spun yarn (B) of a cellulose-based fiber that has not been subjected to a poor dyeing treatment, a step of producing a fabric containing the spun yarn (A1) and the spun yarn (B), and a step of dyeing the fabric, and relates to a method for producing a mélange fiber fabric.

[0009] The present invention is a method for producing a mélange fiber fabric according to another aspect, a step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto a cellulose-based fiber to introduce a carboxyl group, and producing a spun yarn (A2) containing the cellulose-based fiber into which the carboxyl group has been introduced, The cellulose-based fiber with a carboxyl group introduced therein contained in the spun yarn (A2) is subjected to dehydration condensation to obtain the spun yarn (A3) containing a cellulose-based fiber that is difficult to dye, and a dehydration condensation step; A step of preparing a spun yarn (B) of a cellulose-based fiber that has not been subjected to a difficult-to-dye treatment; A step of producing a fabric containing the spun yarn (A3) and the spun yarn (B); And a dyeing step of dyeing the fabric. The present invention relates to a method for producing a melange fiber fabric including these steps.

[0010] The present invention is a method for producing a melange fiber fabric according to another aspect. A step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto a cellulose-based fiber to introduce a carboxyl group, and producing a spun yarn (A2) containing the cellulose-based fiber with the carboxyl group introduced therein; A step of preparing a spun yarn (B) of a cellulose-based fiber that has not been subjected to a difficult-to-dye treatment; A step of producing a fabric containing the spun yarn (A2) and the spun yarn (B); A dehydration condensation step of dehydrating and condensing the cellulose-based fiber with the carboxyl group introduced therein that constitutes the fabric; And a dyeing step of dyeing the fabric after the dehydration condensation step. The present invention relates to a method for producing a melange fiber fabric including these steps.

Advantages of the Invention

[0011] The present invention makes cellulose-based fibers into difficult-to-dye fibers by grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto the cellulose-based fibers to introduce carboxyl groups, and then subjecting the cellulose-based fibers with carboxyl groups introduced (hereinafter sometimes abbreviated as "cellulose-based fibers with carboxyl groups introduced") to dehydration condensation. The cellulose-based fibers with carboxyl groups introduced can be made difficult to dye by dehydration condensation in any state of fiber, yarn, or fabric, and by dyeing the fabric after the difficult-to-dye treatment, a melange fiber fabric can be produced. That is, the present invention can provide cellulose-based difficult-to-dye fibers that can produce melange fiber fabrics such as mottled, tie-dyed, patterned, and frosted patterns by a post-dyeing method without performing water-repellent treatment. In addition, a manufacturing method capable of manufacturing a melange fiber fabric containing the cellulose-based difficult-to-dye fibers can be provided.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0013] (Embodiment 1) [Manufacturing of Cellulose-Based Difficult-to-Dye Fibers] As shown in Fig. 1, in one aspect, the method for producing the cellulose-based hardly-dyeable fiber of the present invention includes a grafting step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond (hereinafter may be abbreviated as "carboxyl group-containing compound") onto a cellulose-based fiber such as sliver (fiber bundle)-shaped cotton to introduce a carboxyl group, and a dehydration condensation step of subjecting the cellulose-based fiber having the carboxyl group introduced thereto to dehydration condensation.

[0014] <Grafting step> The grafting step is, for example, grafting a carboxyl group-containing compound onto a cellulose-based fiber such as sliver-shaped cotton to introduce a carboxyl group derived from the carboxyl group-containing compound. Examples of the carboxyl group-containing compound include compounds containing one ethylenically unsaturated double bond and one or two carboxyl groups. Specifically, at least one carboxylic acid selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid is preferable as the carboxyl group-containing compound. When these compounds are chemically bonded to the surface of a cellulose-based fiber such as cotton, wash resistance can be imparted.

[0015] The grafting of a carboxyl group-containing compound onto a cellulose-based fiber can be carried out by a conventional method. The grafting bond is formed by various reactions such as, for example, a reaction that generates radicals on the surface of the cellulose-based fiber by irradiating an electron beam onto the cellulose-based fiber in a sliver state, and a reaction that grafts a compound group (carboxylic acid group) derived from the carboxyl group-containing compound onto the surface of the cellulose-based fiber as a graft chain by bringing the generated radicals into contact with the carboxyl group-containing compound. As a result, a carboxyl group is introduced into the cellulose-based fiber. The amount of the carboxyl group-containing compound added is preferably 5 to 30% by mass, more preferably 8 to 30% by mass, based on the cellulose-based fiber. Among the carboxyl group-introduced cellulose-based fibers, the mass ratio of the carboxylic acid group that is the graft chain is preferably 5 to 30% by mass, more preferably 8 to 30% by mass. If the addition amount is within the above range, in the method for producing a melange-tone fiber fabric described below, even when blended with untreated fibers such as untreated cotton that are not grafted, a good melange tone can be exhibited, and the proportion of cellulose-based fibers damaged during the graft treatment with an electron beam can be reduced, resulting in a fabric that maintains strength as a whole.

[0016] Taking the case where the cellulose-based fiber is cotton (natural cellulose fiber) as an example, an example of the treatment for grafting is described. In the case of the continuous method, the spinning cotton sliver is irradiated with an electron beam in a nitrogen atmosphere to generate radicals on the surface of the cotton fiber, and immediately thereafter, a carboxyl group-containing compound containing an ethylenically unsaturated double bond is continuously brought into contact. Since the radicals deactivate over time, it is preferable to bring the carboxyl group-containing compound into contact with the surface of the cotton fiber immediately after the electron beam irradiation.

[0017] Also, after electron beam irradiation, continuously bringing the carboxyl group-containing compound into contact with the surface of the cotton fiber is preferable because the carboxyl group-containing compound can efficiently contact the radicals generated on the surface of the cotton fiber. Further, continuously bringing the carboxyl group-containing compound into contact with the surface of the cotton fiber is advantageous for graft bonding to a sliver for spinning of a long material. Further, irradiating the electron beam in a nitrogen atmosphere is preferable because the generated radicals are less likely to be deactivated. Regarding the electron beam irradiation method, a so-called simultaneous irradiation method in which the carboxyl group-containing compound is irradiated simultaneously while being brought into contact with the surface of the cotton fiber is also possible.

[0018] In the case of continuous processing, the shape of the cellulose-based fiber irradiated with the electron beam is preferably a continuous sheet-like shape such as a sliver or a lap, but in the case of batch processing, it is not limited to such a continuous shape.

[0019] The method of bringing the carboxyl group-containing compound into contact with the surface of a cellulose-based fiber such as cotton may be any method such as an immersion method or a spray method. For example, a method of preparing an aqueous solution of the carboxyl group-containing compound and immersing the sliver in the aqueous solution, or a method of spraying the aqueous solution onto the sliver is preferable.

[0020] As described above, in the grafting step, after graft-bonding a carboxyl group-containing compound to a sliver-shaped cellulose-based fiber, preferably, it is washed with water and then dried to obtain a cellulose-based fiber into which a carboxyl group has been introduced.

[0021] <Dehydration condensation step> Cellulose fibers with carboxyl groups introduced are subjected to dehydration condensation due to difficult dyeing. The bonds formed by dehydration condensation are presumed to occur between carboxyl groups introduced into the cellulose fibers or between the carboxyl groups and the hydroxyl groups of the cellulose fibers. For example, the acid anhydride generated by the dehydration condensation reaction reacts with the hydroxyl groups of the cellulose fibers (intramolecular or intermolecular crosslinking by ester bonds). In other words, the hydroxyl groups (functional groups) of the cellulose fibers for the covalent bonding of reactive dyes are blocked by the acid anhydride as a protecting group, and it is presumed that the carboxyl group-introduced cellulose fibers are difficult to dye. However, these are presumptions, and the present invention does not have to be interpreted as being limited to the mechanism of the expression of these effects.

[0022] As the dehydration condensation conditions, at least one method selected from heat treatment at 150 °C or higher under normal pressure, heat vacuum treatment at 140 °C or higher, and addition of a dehydration condensation catalyst is preferable. When performing heat treatment under normal pressure, 160 °C or higher is preferable, and the heating time is preferably 30 to 300 seconds. The degree of vacuum in the case of heat vacuum treatment is preferably about 0.01 to 10 Pa. Any acid catalyst can be used as the dehydration condensation catalyst, and for example, acetic acid can be used.

[0023] [Manufacture of mélange fiber fabric] (Embodiment 2) (1) When making the carboxyl group-introduced cellulose fibers difficult to dye before making the yarn In one aspect of the method for manufacturing the mélange fiber fabric of the present invention, before making the yarn, the carboxyl group-introduced cellulose fibers are made difficult to dye. The production and difficult dyeing of the carboxyl group-introduced cellulose fibers can be performed by the method described in the above (Embodiment 1). One aspect of the method for manufacturing the mélange fiber fabric of the present invention specifically includes the following steps as shown in Figure 2. (a) A spinning step of producing a spun yarn (A1) containing cellulose-based difficult-to-dye fibers produced by the production method of the present invention (b) A step of preparing a spun yarn (B) of cellulose fibers that have not been subjected to difficult dyeing treatment (c) A step of producing a fabric containing the spun yarn (A1) and the spun yarn (B) (d) Step of dyeing the base fabric

[0024] In one aspect of the method for producing a mélange fiber base fabric of the present invention, a base fabric is produced according to a conventional method using a spun yarn (A1) containing a cellulose-based difficult-to-dye fiber and a spun yarn (B) of a normal cellulose-based fiber that has not been subjected to a difficult-to-dye treatment, and the base fabric is dyed. As a result, the spun yarn (A1) containing the cellulose-based difficult-to-dye fiber becomes relatively light in color, and the spun yarn (B) becomes relatively dark in color, and a mélange fiber base fabric with shades is obtained.

[0025] The spun yarn (A1) may be produced by a conventional spinning method. The spun yarn (A1) may be a spun yarn containing 100% by mass of a cellulose-based difficult-to-dye fiber, or may be a blended spun yarn of a cellulose-based difficult-to-dye fiber and an untreated fiber. Preferred untreated fibers are normal cellulose-based fibers that have not been grafted or subjected to a difficult-to-dye treatment. The spun yarn (B) may be a commercially available product, or may be produced, for example, using cotton (natural cellulose fiber) by a conventional spinning method.

[0026] When the total mass of the base fabric containing the spun yarn (A1) and the spun yarn (B) is 100% by mass, the content of the spun yarn (A1) is preferably 20 to 80% by mass. Thereby, the ratio of cellulose-based fibers damaged during the graft treatment with electron beams can be reduced, and a base fabric with overall strength maintained can be obtained.

[0027] The fabric containing the spun yarn (A1) and the spun yarn (B) is a preferable knitted fabric as an inner. For example, when producing using three yarns as supply yarns, one of the three yarns is a blended spun yarn (A1) containing 30% by mass of cellulose-based hardly dyeable fibers and 70% by mass of ordinary untreated cellulose-based fibers (cellulose-based fibers without hardly dyeing treatment), and the remaining two are untreated cellulose-based spun yarns (spun yarn (B) of cellulose-based fibers without hardly dyeing treatment). Then, a fabric containing 10% by mass of cellulose-based hardly dyeable fibers can be obtained. In addition, the supply yarn for producing a preferable knitted fabric as an inner preferably further includes an elastic yarn made of an elastic fiber such as a polyurethane fiber.

[0028] (Embodiment 3) (2) When hardly dyeing carboxyl group-introduced cellulose-based fibers after fabric production In another aspect of the method for producing the melange-colored fiber fabric of the present invention, the carboxyl group-introduced cellulose-based fibers are hardly dyed after fabric production. Specifically, as shown in Figure 3, another aspect of the method for producing the melange-colored fiber fabric of the present invention includes the following steps. (a) A step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto a cellulose-based fiber to introduce a carboxyl group, and producing a spun yarn (A2) containing carboxyl group-introduced cellulose-based fibers (b) A step of preparing a spun yarn (B) of cellulose-based fibers without hardly dyeing treatment (c) A step of producing a fabric containing the spun yarn (A2) and the spun yarn (B), and (d) A dehydration condensation step of dehydrating and condensing the carboxyl group-introduced cellulose-based fibers constituting the fabric (e) A dyeing step of dyeing the fabric after the dehydration condensation step

[0029] In the method for manufacturing a mélange-spun fiber fabric according to this aspect, a fabric containing a spun yarn (A2) containing carboxyl group-introduced cellulose fibers and ordinary cellulose fibers (B) is produced, and the carboxyl group-introduced cellulose fibers that have become the constituent fibers of the fabric are dehydrated and condensed to form cellulose-based poorly dyeable fibers. Then, the fabric is dyed. As a result, the spun yarn (A2) containing cellulose-based poorly dyeable fibers becomes relatively light in color, and the spun yarn (B) becomes relatively dark in color, and a mélange-spun fiber fabric with shades is obtained.

[0030] The spun yarn (A2) may be produced by a conventional spinning method. The spun yarn (A2) may be a spun yarn containing 100% by mass of carboxyl group-introduced cellulose fibers, or may be a blended spun yarn of carboxyl group-introduced cellulose fibers and untreated fibers. The introduction of carboxyl groups into the cellulose fibers can be performed, for example, by the method described in the above (Embodiment 1). Preferred untreated fibers are ordinary cellulose fibers that have not been grafted or poorly dyed. The spun yarn (B) may be a commercially available product, or may be produced, for example, by using cotton (natural cellulose fiber) by a conventional spinning method.

[0031] When the total mass of the fabric containing the spun yarn (A2) and the spun yarn (B) is 100% by mass, the content of the spun yarn (A2) is preferably 20 to 80% by mass. Thereby, the ratio of cellulose fibers damaged during the graft treatment with electron beams can be reduced, and a fabric with overall strength maintained can be obtained.

[0032] The fabric containing the spun yarn (A2) and the spun yarn (B) is a knitted fabric that is preferable as an inner. For example, when producing using three yarns as supply yarns, one of the three yarns is a blended spun yarn (A2) containing 30% by mass of carboxyl group-introduced cellulose fibers and 70% by mass of ordinary untreated cellulose fibers (cellulose fibers not subjected to difficult-dyeing treatment). If the remaining two yarns are untreated cellulose spun yarns (spun yarn (B) of cellulose fibers not subjected to difficult-dyeing treatment), a fabric containing 10% by mass of cellulose-based difficult-dyeing fibers can be obtained through a dehydration condensation step. The above dehydration condensation can be carried out, for example, under the dehydration condensation conditions described in the above (Embodiment 1). In addition, the supply yarn for producing a knitted fabric that is preferable as an inner preferably further includes an elastic yarn made of an elastic fiber such as a polyurethane fiber.

[0033] (Embodiment 4) (3) When making carboxyl group-introduced cellulose fibers difficult to dye after making the yarns and before making the fabric In another aspect of the method for producing a melange-colored fiber fabric of the present invention, after making the yarns and before making the fabric, the carboxyl group-introduced cellulose fibers are made difficult to dye. Specifically, as shown in FIG. 4, another aspect of the method for producing a melange-colored fiber fabric of the present invention includes the following steps. (a) A step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto a cellulose fiber to introduce a carboxyl group, and producing a spun yarn (A2) containing the cellulose fiber into which the carboxyl group has been introduced. (b) A dehydration condensation step of dehydrating and condensing the cellulose fiber into which the carboxyl group has been introduced contained in the spun yarn (A2) to make the spun yarn (A2) into a spun yarn (A3) containing cellulose-based difficult-dyeing fibers, A step of preparing a spun yarn (B) of cellulose fibers not subjected to difficult-dyeing treatment. A step of producing a fabric containing the spun yarn (A3) and the spun yarn (B). A dyeing step of dyeing the fabric.

[0034] The manufacturing method of the mélange fiber fabric of the present invention in this aspect is the same as the above (Embodiment 3), except that after the production of the yarn and before the production of the fabric, the carboxyl group-introduced cellulose fiber is dehydrated and condensed. Therefore, the spun yarn (A2) can be produced by the method described in the above (Embodiment 2), and the dehydration condensation of the carboxyl group-introduced cellulose fiber can be carried out under the dehydration condensation conditions described in the above (Embodiment 1). As the spun yarn (B), preferably, the same one as the above (Embodiment 3) can be used.

[0035] In one aspect, the mélange fiber fabric of the present invention may contain at least one fiber selected from polyester fiber, nylon fiber, acrylic fiber, and polyurethane elastic fiber as the cellulose-based poorly dyeable fiber, the cellulose-based fiber not subjected to the poor dyeing treatment, and the fiber other than the above elastic fiber. In the production of the fabric, when the elastic yarn made of the above polyurethane elastic fiber is used, the obtained fabric is suitable for innerwear such as shirts and pants. The mélange fiber fabric produced by the manufacturing method of the mélange fiber fabric of the present invention is preferably a fabric composed of a spun yarn containing poorly dyeable cotton fiber, a spun yarn of ordinary cotton fiber not subjected to the poor dyeing treatment, and a polyurethane elastic yarn.

[0036] In the manufacturing method of the mélange fiber fabric of the present invention, the dyeing step is carried out on the fabric after the carboxyl group-introduced cellulose fiber is made poorly dyeable, that is, after passing through the dehydration condensation step. In one aspect of the manufacturing method of the mélange fiber fabric of the present invention, preferably, after the dehydration condensation step and before the dyeing step, the fabric includes a scouring and bleaching step.

[0037] By scouring and bleaching, the cellulose-based fiber becomes white. Especially for cotton, if it is not scoured and bleached, its water absorption will decrease, and furthermore, the color tone will be dull, and even if it is dyed, the product value will drop. Scouring and bleaching can be carried out by a conventional method. For example, it can be carried out by immersing the fabric in an aqueous solution obtained by adding hydrogen peroxide (H2O2) and sodium hydroxide (NaOH) to water.

[0038] In the dyeing step, it is preferable to dye the fabric with reactive dyes. After dyeing, conventional methods can be used, such as neutralizing, soaping, and washing with water.

[0039] In one aspect, the method for producing the melange fiber fabric of the present invention preferably includes a finishing process with an aqueous solution containing a water-absorbent softener after the dyeing step. The use of a water-absorbent softener is preferable because it can impart flexibility.

[0040] The fabric is preferably a knitted or woven fabric. Knitted and woven fabrics are suitable as the fabric for inner clothing. In particular, knitted fabrics have elasticity, are flexible, and are suitable as the fabric for inner clothing. For example, 1 to 2 out of 3 yarns or 1 to 3 out of 4 yarns constituting the fabric are preferably blended spun yarns containing cellulosic poorly dyeable fibers, and the remaining yarns are preferably undyed cotton spun yarns. Knitted fabrics include circular knitting, weft knitting, warp knitting (including tricot knitting and raschel knitting), pile knitting, etc., and can be any of plain knitting, honeycomb knitting, rib knitting, smooth knitting (double-sided knitting), rubber knitting, pearl knitting, denim weave, cord weave, atlas weave, chain weave, insertion weave, and combinations thereof. Various interlacing methods are used to produce knitted fabrics. The interlaced knitted fabric can be warp knitted or weft knitted, and examples include tricot, raschel, circular knitting, etc. Also, the knitting structure can be any knitting structure such as half knitting, reverse half knitting, double atlas knitting, double denim knitting, and combinations thereof. Weave structures include plain weave, twill weave, damask weave, changed plain weave, changed twill weave, changed damask weave, irregular weave, figured weave, single ply weave, double weave, multi-layer weave, warp pile weave, weft pile weave, interlaced weave, or combinations thereof. Among these, weft knitted fabrics including circular knitting or warp knitted fabrics are preferable.

[0041] The mass per unit area of the fabric is preferably 80 to 300 g / m 2 more preferably 90 to 250 g / m 2 even more preferably 100 to 200 g / m 2 If the mass per unit area of the fabric is within the above range, it is suitable as inner clothing.

Example

[0042] The present invention will be described in more detail by the following examples. It should be noted that the present invention is not limited to the following examples.

[0043] (Example 1) <Processing of sliver> For cotton sliver (mass per unit length, unit greige: 25.0 g / 6 yd (4.6 g / m)), an electron beam was irradiated at 40 kGy and an acceleration voltage of 200 kV under a nitrogen atmosphere using an electro-curtain type electron beam irradiator EC250 / 30 / 90L (manufactured by Iwasaki Electric Co., Ltd.). The sliver irradiated with the electron beam was immediately immersed in a 16% by mass aqueous solution of acrylic acid (manufactured by Nacalai Tesque, Inc.) containing 0.5% by mass of a penetrant, and squeezed with a mangle to a pickup rate of about 100% by mass based on the sliver weight. Next, the sliver was washed with water to remove unreacted acrylic acid, dried at 80°C, coiled in a container and stored to obtain acrylic acid-grafted cotton (sliver, hereinafter referred to as "treated cotton"). 8% by mass of acrylic acid was graft-bonded to this treated cotton.

[0044] <Manufacture of spun yarn> (1) Blended spun yarn containing treated cotton (carboxyl group-introduced cellulose-based fiber) The treated cotton and the untreated cotton were blended in a cotton mixing process to spin a yarn of cotton count 50. The proportion of treated cotton in the blended spun yarn was set to 30% by mass. (2) Untreated cotton spun yarn A yarn of yarn count 50 was spun using untreated cotton.

[0045] <Manufacture of knitted fabric> A blended yarn containing the treated cotton and an untreated cotton spun yarn were used, and the blended yarn containing the treated cotton was used as a supply yarn at a ratio of 1 part to 2 parts of the untreated cotton spun yarn. Using a circular knitting machine, a knitted fabric with a ribbed knit structure was knitted to obtain a fabric containing 10% by mass of the treated cotton. Thereafter, the knitted fabric was heat-treated (dehydration condensation step) at 180 ° C for 90 seconds to make the treated cotton a cellulose-based poorly dyeable fiber. As a result, a fabric containing 10% by mass of poorly dyeable cotton was obtained.

[0046] <Scouring, Bleaching, Dyeing> The obtained knitted fabric was subjected to scouring and bleaching treatment and dyeing treatment according to a conventional method. Reactive dyes were used for dyeing, and the fabric was dyed gray.

[0047] Fig. 5 shows an enlarged photograph of the dyed fabric of Example 1. As shown in Fig. 5, it was confirmed that a non-uniform and mottled melange fiber fabric was obtained, and a melange fiber fabric could be produced without a water-repellent treatment.

[0048] (Example 2) <Treatment of Sliver> In the same manner as in Example 1, acrylate-grafted cotton (sliver) was obtained, and then heat-treated (dehydration condensation step) at 180 ° C for 90 seconds to make the treated cotton poorly dyeable cotton.

[0049] <Manufacture of Spun Yarn> (1) Blended Yarn Containing Poorly Dyeable Cotton The poorly dyeable cotton and the untreated cotton were blended in a cotton mixing process, and a yarn of cotton count 50 was spun. The ratio of the poorly dyeable cotton in the blended yarn was set to 30% by mass. (2) Untreated Cotton Spun Yarn Using untreated cotton, a yarn of yarn count 50 was spun.

[0050] <Manufacture of Knitted Fabric> A blended yarn containing the difficult-to-dye cotton and an untreated cotton spun yarn were used, and the blended yarn containing the difficult-to-dye cotton was used as a supply yarn at a ratio of 1 to 2 untreated cotton spun yarns. A knitted fabric with a plain weave structure was knitted using a circular knitting machine to obtain a fabric containing 10% by mass of the difficult-to-dye cotton.

[0051] <Scouring, bleaching, dyeing> The obtained knitted fabric was subjected to scouring and bleaching treatments and a dyeing treatment according to a conventional method. Reactive dyes were used for dyeing, and the fabric was dyed gray. It was confirmed that, as in Example 1, a non-uniform and melange-like fiber fabric could be obtained in Example 2, and a melange-like fiber fabric could be produced without a water-repellent treatment.

Industrial Applicability

[0052] The manufacturing method of the present invention can also be applied to denim-like fabrics, sports clothing, summer clothing, etc. It can also be applied to the manufacture of shoes, hats, bags, curtains, sofa covers, etc.

Claims

1. A method for producing a cellulose-based poorly dyeable fiber, comprising: a grafting step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto a cellulose-based fiber to introduce a carboxyl group; and a dehydration condensation step of dehydrating and condensing the cellulose-based fiber having the carboxyl group introduced therein, the method for producing a cellulose-based poorly dyeable fiber.

2. The method for producing a cellulose-based poorly dyeable fiber according to claim 1, wherein the bond formed by the dehydration condensation occurs between carboxyl groups introduced into the cellulose-based fiber or between the carboxyl group and a hydroxyl group of the cellulose fiber.

3. The method for producing a cellulose-based poorly dyeable fiber according to claim 1 or 2, wherein the dehydration condensation is caused by at least one method selected from heat treatment at 150°C or higher, heat vacuum treatment at 140°C or higher, and addition of a dehydration condensation catalyst.

4. The method for producing a cellulose-based poorly dyeable fiber according to claim 1 or 2, wherein the grafting step and the dehydration condensation step are performed on the sliver-shaped cellulose-based fiber.

5. A spinning step of producing a spun yarn (A1) containing a cellulose-based poorly dyeable fiber produced by the production method according to any one of claims 1 to 4; a step of preparing a spun yarn (B) of a cellulose-based fiber that has not been subjected to a poorly dyeable treatment; a step of producing a fabric containing the spun yarn (A1) and the spun yarn (B); and a step of dyeing the fabric, the method for producing a melange fiber fabric.

6. A method for producing a melange fiber fabric, comprising: a step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto a cellulose-based fiber to introduce a carboxyl group, and producing a spun yarn (A2) containing the cellulose-based fiber having the carboxyl group introduced therein; a dehydration condensation step of dehydrating and condensing the cellulose-based fiber having the carboxyl group introduced therein contained in the spun yarn (A2) to obtain the spun yarn (A2) as a spun yarn (A3) containing a cellulose-based poorly dyeable fiber; a step of preparing a spun yarn (B) of a cellulose-based fiber that has not been subjected to a poorly dyeable treatment; a step of producing a fabric containing the spun yarn (A3) and the spun yarn (B); and a dyeing step of dyeing the fabric, the method for producing a melange fiber fabric.

7. A method for producing a melange fiber fabric, comprising: A step of grafting a carboxyl group-containing compound containing an ethylenically unsaturated double bond onto a cellulose fiber to introduce a carboxyl group, and producing a spun yarn (A2) containing the cellulose fiber into which the carboxyl group has been introduced A step of preparing a spun yarn (B) of a cellulose fiber that has not been subjected to a difficult-to-dye treatment A step of producing a fabric containing the spun yarn (A2) and the spun yarn (B) A dehydration condensation step of dehydrating and condensing the cellulose fiber into which the carboxyl group has been introduced and constituting the fabric A dyeing step of dyeing the fabric after the dehydration condensation step, which is a method for producing a melange fiber fabric

8. The method for producing a melange fiber fabric according to any one of claims 5 to 7, wherein the fabric is a knitted fabric or a woven fabric

9. The method for producing a melange fiber fabric according to any one of claims 5 to 8, wherein the fabric further contains at least one fiber selected from polyester fibers, nylon fibers, acrylic fibers, and polyurethane elastic fibers

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