Dye composition for polylactic acid fiber and dyeing method

Abstract

The invention relates to a dye composition for polylactic acid fibers and a dyeing method. [Problem] The purpose of the present invention is to provide: a dye composition for polylactic acid fibers, which has excellent dye absorbability with respect to polylactic acid fibers, yellow disperse dyes, red disperse dyes, and blue disperse dyes, and which has good reproducibility, while having uniform dye uptake rates during dyeing of the colors; and a dyeing method. [Solution] Provided is a dye composition for polylactic acid fibers, which contains a yellow disperse dye represented by formula (1) and / or formula (2), a red disperse dye represented by formula (3), and a blue disperse dye that is a mixture of a blue disperse dye represented by formula (4) and / or two isomers represented by formula (5). # imgabs0 # (In the formula, R1 represents a methyl group or an ethyl group. ) # imgabs1 # (In the formula, R2 represents a methyl group or an ethyl group. ) # imgabs2 # (In the formula, one of X1 and X2 represents NO2, and the other represents OH).

Description

Technical Field

[0001] The present invention relates to a method for dyeing polylactic acid fibers using disperse dyes, and more particularly to a dye composition containing a yellow disperse dye, a red disperse dye, and a blue disperse dye, and a method for dyeing polylactic acid fibers and the like using the same. Background Art

[0002] Against the backdrop of recent environmental issues, polylactic acid fibers have attracted attention as non-petroleum-based biodegradable fibers.

[0003] Unlike petroleum, a raw material for existing plastics, polylactic acid fiber can be harvested annually from renewable plant resources such as corn, and therefore polylactic acid fiber is expected to contribute to the realization of a sustainable society (eg, Non-Patent Document 1).

[0004] Plant-derived synthetic fibers such as polylactic acid fibers are obtained by fixing carbon dioxide gas in the ecosystem. Therefore, carbon dioxide gas originally in the ecosystem produced by combustion or biodegradation based on microorganisms can be restored to its original state without affecting the carbon dioxide gas on the earth, becoming a carbon-neutral raw material.

[0005] The characteristics of polylactic acid fibers include functions such as biodegradability, soft touch, light weight, sweat absorption and quick drying, mild antibacterial properties, weak acidity that is friendly to the skin, and other new charms that are not seen in existing synthetic fibers, such as comfort. There is great expectation that polylactic acid fibers will be used as a general-purpose fiber to replace polyester.

[0006] (For example, non-patent document 2).

[0007] It is found that polylactic acid fibers are most suitable for dyeing with disperse dyes, but the dye exhaustion rate varies depending on the dye, color matching is difficult, and reproducibility is not very good.

[0008] In addition, polylactic acid fibers have poorer heat resistance than polyester fibers, and therefore have problems such as becoming hard in texture by heat treatment and hydrolysis under high temperature (60° C. or higher) and high humidity conditions.

[0009] The conventional disperse dye compositions described in Patent Documents 1 to 3 are disperse dyes that can dye polylactic acid fibers, but they are not satisfactory as trichromatic dyes with excellent reproducibility.

[0010] When dyeing is performed using three primary color dyes, by making the dyeing speeds of the three primary colors substantially equal, reproducibility becomes good, and the problem of color difference between the laboratory and the field and the problem of poor reproducibility are eliminated, leading to improved productivity.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent No. 4346611

[0014] Patent Document 2: Japanese Patent No. 4424466

[0015] Patent Document 3: Japanese Patent Application Publication No. 2006-8871

[0016] Non-patent literature

[0017] Non-patent document 1: Journal of the Japanese Society of Textile Machinery, Vol. 56 (2003) No. 3, p. 133-136

[0018] Non-patent document 2: "Journal of the Japanese Society of Fiber Science" vol.59 No.10 (2003) p329-332 Summary of the invention

[0019] Problem that the invention aims to solve

[0020] In order to solve these problems, there are provided: a high-performance disperse dye composition having excellent exhaustion of yellow disperse dyes, red disperse dyes and blue disperse dyes for polylactic acid fibers, or having a uniform dyeing speed, good reproducibility and excellent light fastness when dyeing each color, and a dyeing method using the same.

[0021] Solutions for solving problems

[0022] The present inventors conducted intensive research to solve the above-mentioned problems and found that by combining yellow disperse dyes, red disperse dyes and blue disperse dyes, a dye composition having excellent dyeing exhaustion for polylactic acid fibers, consistent dyeing characteristics during dyeing, or excellent light fastness was obtained, thereby completing the present invention.

[0023] That is, the present invention relates to the following (1) to (8).

[0024] (1) A dye composition for polylactic acid fiber, comprising:

[0025] A yellow disperse dye represented by the following formula (1) and / or the following formula (2),

[0026] A red disperse dye represented by the following formula (3), and

[0027] A blue disperse dye represented by the following formula (4) and / or a mixture of two isomers represented by the following formula (5).

[0028]

[0029] (Where R 1 represents a methyl or ethyl group. )

[0030]

[0031] (Where R 2 represents a methyl or ethyl group. )

[0032]

[0033] (Where X 1 and X 2 One of them means NO 2 , the other represents OH. )

[0034] (2) A dye composition for polylactic acid fibers according to (1), further comprising: a mixture of two pigment compounds represented by the following formula (6) in an amount of less than 5 parts by weight, when the total amount of the yellow disperse dye, the red disperse dye, and the blue disperse dye is set to 100 parts by weight.

[0035]

[0036] (Where R 3 represents a methyl or methylethyl ether group. )

[0037] (3) The dye composition for polylactic acid fibers according to (1) or (2), wherein the disperse dye is dispersed in water using a dispersant.

[0038] (4) A dye composition for polylactic acid fiber according to (3), wherein the dispersant is one or more compounds selected from the group consisting of formaldehyde condensates of naphthalenesulfonic acid and alkylbenzenesulfonic acid, formaldehyde condensates of naphthalenesulfonic acid, formaldehyde condensates of cresolsulfonic acid, formaldehyde condensates of cresol and 2-naphthol-6-sulfonic acid, formaldehyde condensates of alkylnaphthalenesulfonic acid, formaldehyde condensates of creosote sulfonic acid, lignin sulfonic acid, block copolymers of ethylene oxide and propylene oxide, ethylene oxide adducts of alkylphenols, and ethylene oxide adducts of polystyrenated phenol.

[0039] (5) The dye composition for polylactic acid fibers according to any one of (1) to (4), wherein the content of quinoline contained as impurities derived from the dispersant is less than 1000 ppm.

[0040] (6) A dyed polylactic acid fiber product obtained by dyeing the polylactic acid fiber using the dye composition for polylactic acid fibers according to any one of (1) to (5).

[0041] (7) A method for dyeing polylactic acid fibers, comprising the steps of: diluting the polylactic acid fiber dye composition described in any one of (1) to (5) to prepare a dyeing dispersion; and immersing the polylactic acid fibers in the dyeing dispersion.

[0042] (8) The method for dyeing polylactic acid fibers according to (7), wherein in the immersing step, the temperature of the dye composition for polylactic acid fibers is set to 110 to 120°C.

[0043] Effects of the Invention

[0044] The present invention can provide: a dye composition for polylactic acid fiber, which has excellent exhaustion of yellow disperse dyes, red disperse dyes and blue disperse dyes for polylactic acid fiber, and has a uniform dyeing speed, excellent reproducibility and excellent light fastness, and a dyed product and a dyeing method using the same. DETAILED DESCRIPTION

[0045] The present invention will be described in detail below: The dye composition for polylactic acid fibers of the present invention contains a yellow disperse dye, a red disperse dye, and a blue disperse dye.

[0046] The yellow disperse dye contains the following formula (1) and / or the following formula (2).

[0047]

[0048] The compound represented by formula (1) is CIDISPERSE ORANGE 61, which can also be produced by a method known in the literature or by applying the method, but a commercially available compound or a compound used can be used. The compound represented by formula (2) is CIDISPERSE ORANGE 155, which can also be produced by a method known in the literature or by applying the method, but a commercially available compound or a compound used can be used.

[0049] The red disperse dye is a compound represented by the following formula (3).

[0050]

[0051] (Where R 1 represents a methyl or ethyl group. )

[0052] The compound represented by formula (3) is CIDISPERSE RED 167 or CIDISPERSE RED 167.1, and can be produced by a method known in the literature or by applying the method. However, a commercially available compound or a used compound can be used.

[0053] The blue disperse dye contains a blue disperse dye represented by the following formula (4) and / or a mixture of two isomers represented by the following formula (5).

[0054]

[0055] (Where R 2 represents a methyl or ethyl group. )

[0056]

[0057] (Where X 1 and X 2 One of them means NO 2 , the other represents OH. )

[0058] The compound represented by formula (4) is CIDISPERSE BLUE 79 or CIDISPERSE BLUE 79.1, and can be produced by a method known in the literature or by applying the method, but a commercially available compound or a used compound can be used.

[0059] The two isomer mixture represented by formula (5) is CIDISPERSE BLUE 54, which can also be produced by a method known in the literature or by applying the method, but a commercially available compound or a compound used can be used.

[0060] The dye composition for polylactic acid fiber comprises a dye mixture of a yellow disperse dye represented by formula (1) and / or the following formula (2), a red disperse dye represented by formula (3), and a blue disperse dye represented by formula (4) and / or a blue disperse dye which is a mixture of two isomers represented by formula (5). The ratio is not particularly limited, but it preferably contains 10 to 90% by weight of the yellow disperse dye, 2 to 90% by weight of the red disperse dye, and 10 to 90% by weight of the blue disperse dye, and more preferably contains 20 to 50% by weight of the yellow disperse dye, 2 to 40% by weight of the red disperse dye, and 20 to 70% by weight of the blue disperse dye.

[0061] The dye composition for polylactic acid fibers may further contain a mixture of two kinds of pigment compounds represented by the following formula (6).

[0062]

[0063] (Where R 3 represents a methyl or ethyl methyl ether group. )

[0064] By containing a mixture of two pigment compounds shown in formula (6), the color rendering of the dyed product can be improved. The mixture of two pigment compounds shown in formula (6) is CIDISPERSE BLUE 204, which can also be manufactured by a method known in the literature or by applying it, but commercially available compounds can also be used. When the total amount of the aforementioned yellow disperse dye, the aforementioned red disperse dye, and the aforementioned blue disperse dye is set to 100 parts by mass, the content of the mixture of two pigment compounds shown in formula (6) in the polylactic acid fiber dye composition is preferably 0.1 parts by mass or more and less than 5 parts by mass.

[0065] The polylactic acid fiber dye composition preferably further contains a dispersant, and preferably disperse dyes are dispersed in water by dispersants. As dispersants, for example, formaldehyde condensates of naphthalenesulfonic acid and alkylbenzenesulfonic acid, formaldehyde condensates of naphthalenesulfonic acid, formaldehyde condensates of cresolsulfonic acid, formaldehyde condensates of cresol and 2-naphthol-6-sulfonic acid, formaldehyde condensates of alkylnaphthalenesulfonic acid, formaldehyde condensates of creosote sulfonic acid, ligninsulfonic acid, block copolymers of ethylene oxide and propylene oxide, ethylene oxide adducts of alkylphenols and ethylene oxide adducts of polystyrenated phenols can be cited. One or more compounds in the group are formed. These dispersants can be obtained from the market. By using these dispersants, disperse dyes can be dispersed in water. The content of the dispersant in the disperse dye composition is calculated by solid content conversion, preferably 30 to 80% by mass, more preferably 50 to 80% by mass. Disperse dyes can be dispersed in water according to known methods.

[0066] Quinoline contained as an impurity derived from the dispersant is preferably less than 1000 ppm. Quinoline is represented as a pollutant in the dispersant and is classified as a carcinogenic substance. In addition, it is highly water-soluble and toxic to aquatic organisms. In recent years, it has become a restricted substance of REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) and bluesign (registered trademark).

[0067] The disperse dye composition can be prepared by mixing disperse dyes, and any selected dispersant and any selected other ingredients. The disperse dye composition is preferably micronized. The micronization can be carried out as follows: in the presence of a small amount of water, the disperse dye composition is fully wet-pulverized until it is generally about 0.2 to 1.0 μm using a pulverizer such as a ball mill or a sand mill, thereby being able to be carried out. The disperse dye composition can be in a liquid or paste state without micronization, or in a powdered form dried by a spray drying method or the like.

[0068] As other components, for example, dust-free agent, mildewproof agent, defoamer, penetrant, pH adjuster, etc. can be contained. As these components, common substances can be used, and the content in the disperse dye composition can be appropriately adjusted as long as it does not damage the dyeability of the polylactic acid fiber.

[0069] The method for dyeing polylactic acid fibers is described below. The method for dyeing polylactic acid fibers is not limited to the following description. The method for dyeing polylactic acid fibers is characterized by including a step of immersing polylactic acid fibers in a dyeing dispersion.

[0070] The dye dispersion can be prepared by adding the disperse dye composition to water and mixing.

[0071] The pH of the dye dispersion is preferably adjusted to 4 to 5. The pH can be adjusted by adding a commonly used pH adjuster such as acetic acid and sodium acetate. The content of the disperse dye in the dye dispersion is preferably adjusted to 0.005 to 10% owf relative to the mass of the polylactic acid fiber to be dyed.

[0072] The dyeing conditions and the like can be based on known conditions and are not particularly limited. For example, it is preferred that the polylactic acid fiber be impregnated and dyed under pressure, preferably at about 110 to 120° C., preferably at a temperature of 115 to 120° C., for 30 minutes to 1 hour. By increasing the temperature, the dye exhaustion rate increases, and it becomes easy to obtain a dark or black tone. In addition, the dye exhaustion rate increases, so that the dyeing solution remaining in the residual bath decreases, and the reproducibility becomes better.

[0073] After the dyeing step, the dyed polylactic acid fibers are preferably subjected to water washing, soap washing, reduction washing, or the like in order to remove undyed dye on the fiber surface.

[0074] The soap washing, reduction washing and other treatments are preferably performed at 60° C. or lower. When the treatment is performed at 65° C. or higher, the temporarily dyed disperse dye may fall off from the polylactic acid fiber, which may cause a decrease in concentration.

[0075] According to this dyeing method, sufficient properties for practical use, such as high light fastness and washing fastness, good color and sufficient dyeing reproducibility can be achieved.

[0076] Next, the polylactic acid-based fibers will be described.

[0077] The polylactic acid fiber used this time uses corn raw materials and is of a grade suitable for fiber grades, maintaining strength that can withstand use as a raw material for clothing products. In addition, conventional polylactic acid fibers solidify when dyeing temperatures reach 100°C to 110°C or higher, but it has been confirmed that solidification does not occur even at high dyeing temperatures of 120°C to 130°C.

[0078] Example

[0079] The present invention will be described in detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. In the Examples, "%" means "mass %". In addition, CIDISPERSE means a common name of the Color Index.

[0080] [Suitability of disperse dyes for dyeing polylactic acid fibers]

[0081] The disperse dyes shown in the following Nos. 1 to 44 were used. As the disperse dyes shown in the following Nos. 1 to 44, commercially available disperse dyes were used.

[0082] [1] A dispersant consisting of a formaldehyde condensate of naphthalenesulfonic acid and sodium lignin sulfonate in equal amounts with each pigment compound listed in Table 1 is mixed, a trace amount of a dust-removing agent is added, and the mixture is micronized and dried in a conventional manner to prepare a dye composition for polylactic acid fibers.

[0083] [2] Dyeing of polylactic acid fibers

[0084] The amount of dyeing material that can obtain 1.0% owf of disperse dye is measured, and after adding 0.5 g / L of dispersing leveling agent KP Leveller AL (manufactured by Nippon Kayaku Co., Ltd., anionic surfactant), it is added to water adjusted to pH 4.5 by acetic acid and sodium acetate, and the total amount is adjusted to 100 mL. 5 g of polylactic acid white cloth (manufactured by HIGHCHEM CO., LTD.) is immersed in the dye bath (dye dispersion liquid) and dyed at 120°C for 60 minutes. For the dyed polylactic acid dyed cloth, water is added to 3 g / L of soda ash, 3 g / L of sulfoxylate, and 1 g / L of SUNMORL RC-700E (manufactured by Nichika Chemical Co., Ltd., anionic surfactant) to make a total amount of 100 mL in a bath, and reduction cleaning is performed at 60°C for 10 minutes (sulfoxylate is added at 60°C), and then washed with water and dried to obtain a dyeing material.

[0085] [3] Residue dyeing of polyester fibers

[0086] The total amount of the dyeing liquid remaining in the tank was adjusted to 80 mL, 4 g of Polyester Tropical (manufactured by Seisen Co., Ltd.) was immersed, and dyeing was performed at 135°C for 30 minutes.

[0087] Table 1 shows the dyeing suitability of each disperse dye for polylactic acid fibers.

[0088] [Table 1]

[0089] No. Dye Index Dyeing property No. Dye Index Dyeing property 1 C.I.Disperse Yellow 42 〇 23 C.I.Disperse Yellow 64 △ 2 C.I.Disperse Yellow 54 〇 24 C.I.Disperse Yellow 114 × 3 C.I.Solvent Yellow 163 〇 25 C.I.Disperse Yellow 163 × 4 C.I.Disperse Orange 30 〇 26 C.I.Disperse Yellow 211 × 5 C.I.Disperse Orange 61 〇 27 C.I.Disperse Red 86 × 6 C.I.Disperse Orange 73 〇 28 C.I.Disperse Red 145 × 7 C.I.Disperse Orange 155 〇 29 C.I.Disperse Red 152 × 8 C.I.Disperse Red 60 〇 30 C.I.Disperse Red 153 × 9 C.I.Disperse Red 73 〇 31 C.I.Disperse Red 179 △-× 10 C.I.Disperse Red 92 〇-△ 32 C.I.Disperse Red 191 × 11 C.I.Disperse Red 146 〇 33 C.I.Disperse Violet 93 △-× 12 C.I.Disperse Red 154 〇 34 C.I.Disperse Blue 56 △ 13 C.I.Disperse Red 167.1 〇-△ 35 C.I.Disperse Blue 60 × 14 C.I.Disperse Red 258 〇-△ 36 C.I.Disperse Blue 73 × 15 C.I.Disperse Violet 26 ○ 37 C.I.Disperse Blue 73.1 × 16 C.I.Disperse Blue 54 〇-△ 38 C.I.Disperse Blue 77 × 17 C.I.Disperse Blue 79.1 〇 39 C.I.Disperse Blue 165 × 18 C.I.Disperse Blue 148 ○ 40 C.I.Disperse Blue 183 △ 19 C.I.Disperse Blue 204 〇-△ 41 C.I.Disperse Blue 257 △ 20 C.I.Disperse Blue 284 〇 42 C.I.Disperse Blue 291 △ 21 C.I.Disperse Blue 340 〇 43 C.I.Disperse Blue291.1 △ 22 C.I.Disperse Blue 341 〇 44 C.I.Disperse Blue 366 ×

[0090] (Judgment method)

[0091] The dyeing exhaustion of the polylactic acid fiber and the polyester obtained by residual bath dyeing was evaluated. Dyeing exhaustion: ○ good △ slightly poor × poor

[0092] The results in Table 1 show that the dyeing properties of the dyed products obtained in Nos. 1 to 22 are good, and the dyeing properties of the dyed products obtained in Nos. 23 to 44 are poor. The results show that the dyed products obtained in Nos. 1 to 22 have good dyeing properties for polylactic acid fibers.

[0093] [Example 1: Dye composition for polylactic acid fiber]

[0094] A yellow pigment, a red pigment and a blue pigment are mixed in the ratio shown in Table 2, and a dispersant composed of a formaldehyde condensate of naphthalenesulfonic acid and sodium lignin sulfonate in an amount equal to that of the pigment mixture is mixed, a trace amount of a dust-free agent is added, and micronization and drying are performed by conventional methods to adjust the dye composition for polylactic acid fiber.

[0095] [Examples 2 to 7: Dye composition for polylactic acid fiber]

[0096] A dye composition for polylactic acid fibers was prepared according to the same procedure as in Example 1 except that the dyes shown in Table 2 were used.

[0097] [Comparative Examples 1 to 6: Dye compositions for polylactic acid fibers]

[0098] A dye composition for polylactic acid fibers was prepared according to the same procedure as in Example 1 except that the dyes shown in Table 3 were used.

[0099] [STEP DYEING TEST]

[0100] The amount of dyeing material that can obtain a total of 1.0% owf (composition ratio, see Table 2) of the dye composition for polylactic acid fiber is measured, and after adding 0.5 g / L of a dispersing and leveling agent KP Leveller AL (manufactured by Nippon Kayaku Co., Ltd., anionic surfactant), it is added to water adjusted to pH 4.5 by acetic acid and sodium acetate, and the total amount is adjusted to 100 mL. 5 g of polylactic acid white cloth ("Highlact", manufactured by HIGHCHEM CO., LTD.) is immersed in the dye bath (dye dispersion liquid), and the temperature is raised by 1°C in 1 minute from 50°C, and the polylactic acid dyeing material is taken out from the dye bath at 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 120°C for 30 minutes, and 120°C for 60 minutes, and the dyeing at each temperature is terminated. The dyed polylactic acid dyed cloth was placed in a bath containing 3 g / L of soda ash, 3 g / L of sulfoxylate, and 1 g / L of SUNMORL RC-700E (manufactured by Nichika Chemical Co., Ltd., anionic surfactant) and water added to make the total amount 100 mL, and reduction cleaning (sulfoxylate was added at 60° C.) was performed at 60° C. for 10 minutes, followed by washing with water and drying to obtain a dyed product.

[0101] [Residual liquid dyeing of polyester fiber]

[0102] The remaining dyeing liquid was taken out of the tank at each temperature, and the total amount was adjusted to 80 mL, 4 g of Polyestertropical (manufactured by Seisen Co., Ltd.) was immersed, and dyeing was carried out at 135° C. for 30 minutes. The compounding values ​​in Table 2 are expressed in mass %.

[0103] (Determination method of dyeing speed)

[0104] The dyeing speed was determined from the dyed products of polylactic acid fibers and the polyester dyed products obtained by residual bath dyeing at each temperature. The dyeing speed of each dispersion composition on polylactic acid fibers is shown in Tables 2 and 3.

[0105] Dyeing speed determination criteria

[0106] A: The dyeing speed is very consistent

[0107] B: The dyeing speed is relatively consistent.

[0108] C: Dyeing speed is consistent to some extent

[0109] D: The dyeing speed is not consistent

[0110] E: The dyeing speed is obviously inconsistent

[0111] [Light fastness test]

[0112] The amount of dyeing material that can obtain a total of 3.0% owf (composition ratio reference table 2) of the dye composition for polylactic acid fiber was measured, and after adding 0.5 g / L of a dispersing and leveling agent KP Leveller AL (manufactured by Nippon Kayaku Co., Ltd., anionic surfactant), it was added to water adjusted to pH 4.5 by acetic acid and sodium acetate, and the total amount was adjusted to 100 mL. 5 g of polylactic acid white cloth ("Highlact", manufactured by HIGHCHEM CO., LTD.) was immersed in the dye bath (dye dispersion liquid), and the polylactic acid dyeing material was taken out from the dye bath at 120°C after 60 minutes, and the dyeing at each temperature was terminated. The dyed polylactic acid dyed cloth was placed in a bath containing 3 g / L of soda ash, 3 g / L of sulfoxylate, and 1 g / L of SUNMORL RC-700E (manufactured by Nichika Chemical Co., Ltd., anionic surfactant) and water added to make the total amount 100 mL, and reduction cleaning (sulfoxylate was added at 60° C.) was performed at 60° C. for 10 minutes, followed by washing with water and drying to obtain a dyed product.

[0113] The light fastness test was conducted as follows: Xenon Weather Meter NX75 from Suga Test Instruments Co., Ltd. was used as the test apparatus and conducted under the conditions of Method A of the xenon arc light color fastness test in JIS L0843:2006. Discoloration and fading of the irradiated portion were determined by the Blue Scale of JIS L0841:2004. The results are shown in Tables 2 and 3. For light fastness, Grade 4 or higher is desirable when high fastness is required.

[0114] [Table 2]

[0115]

[0116] [Table 3]

[0117]

[0118] The results in Table 2 show that the dyeings obtained in Examples 1 to 7 have good dyeing speeds, excellent light fastness, and excellent performance as polylactic acid dyeings. In addition, the results in Table 3 show that the dyeing speeds of the dyeings obtained using Comparative Examples 1 to 6 are inconsistent and the reproducibility is poor. In addition, the color rendering of the dyeing obtained using Example 2 is also improved.

Claims

1. A dye composition for polylactic acid fiber, comprising: A yellow disperse dye represented by the following formula (1) and / or the following formula (2), A red disperse dye represented by the following formula (3), and A blue disperse dye represented by the following formula (4) and / or a blue disperse dye of a mixture of two isomers represented by the following formula (5), In the formula, R 1 represents a methyl or ethyl group, In the formula, R 2 represents a methyl or ethyl group, In the formula, X 1 and X 2 One represents NO2 and the other represents OH.

2. The dye composition for polylactic acid fiber according to claim 1, wherein The invention further comprises: a mixture of two pigment compounds represented by the following formula (6) in an amount of less than 5 parts by mass when the total amount of the yellow disperse dye, the red disperse dye and the blue disperse dye is 100 parts by mass, In the formula, R 3 It represents a methyl or methylethyl ether group.

3. The polylactic acid fiber dye composition according to claim 1 or 2, wherein The disperse dye is dispersed in water by a dispersant.

4. The dye composition for polylactic acid fiber according to claim 3, wherein The dispersant is one or more compounds selected from the group consisting of formaldehyde condensates of naphthalenesulfonic acid and alkylbenzenesulfonic acid, formaldehyde condensates of naphthalenesulfonic acid, formaldehyde condensates of cresolsulfonic acid, formaldehyde condensates of cresol and 2-naphthol-6-sulfonic acid, formaldehyde condensates of alkylnaphthalenesulfonic acid, formaldehyde condensates of creosote sulfonic acid, ligninsulfonic acid, block copolymers of ethylene oxide and propylene oxide, ethylene oxide adducts of alkylphenols, and ethylene oxide adducts of polystyrenated phenols.

5. The dye composition for polylactic acid fibers according to any one of claims 1 to 4, wherein The content of quinoline contained as impurities derived from the dispersant was less than 1000 ppm. 6 . A polylactic acid fiber dyed product obtained by dyeing with the polylactic acid fiber dye composition according to claim 1 .

7. A method for dyeing polylactic acid fibers, comprising the steps of: diluting the dye composition for polylactic acid fibers according to any one of claims 1 to 5 to prepare a dyeing dispersion; and immersing the polylactic acid fibers in the dyeing dispersion.

8. The method for dyeing polylactic acid fibers according to claim 7, wherein: In the immersion step, the temperature of the dye composition for polylactic acid fibers is set to 110 to 120°C.

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