JP2009167585A - Method for producing dyed fabric structure, dyed fabric structure, and fiber products - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a dyed fabric structure containing a polylactic acid fiber, excellent in color fastness to dyeing, and having a small reduction in fiber strength under wet heat environment, to provide a dyed fabric structure obtained by the production method, and to provide fiber products using the dyed fabric structure. <P>SOLUTION: A fabric structure A which contains polylactic acid fibers having a melting point of 195°C is subjected to dyeing treatment and subsequent reduction cleaning treatment to provide the dyed fabric structure, and then, if necessary, the dyed fabric structure is formed into fiber products such as clothes, automobile interior materials, and interior products. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dyed fiber structure containing polylactic acid fibers, a method for producing a dyed fiber structure having excellent dyeing fastness and a small decrease in fiber strength in a moist heat environment, and the method The present invention relates to a dyed fiber structure obtained by the above, and a garment using the dyed fiber structure.

  Since polylactic acid fibers have excellent characteristics such as biodegradability and low environmental load, they are widely used as clothing and interior products (see, for example, Patent Document 1 and Patent Document 2). However, the polylactic acid fiber has an excellent characteristic of biodegradability, but has a drawback that the fiber strength is easily lowered under heat and humidity.

  On the other hand, when the polylactic acid fiber is used as clothing, it is usually dyed to enhance fashionability. At that time, disperse dyes for polyethylene terephthalate fibers are generally used as the dyes used, but polylactic acid fibers, unlike aromatic polyester fibers such as polyethylene terephthalate fibers, are susceptible to hydrolysis, so they can be dyed at low temperatures. There is a need to do. As a result, the diffusion of the dye into the polylactic acid fiber does not proceed, and the amount of the dye adhering to the surface of the polylactic acid fiber increases.

  In addition, when performing a dyeing process using a disperse dye, it is common to perform a reduction cleaning using a reducing agent such as hydrosulfite and thione urea dioxide under strong alkaline conditions in order to improve dyeing fastness. . However, polylactic acid fibers are susceptible to hydrolysis under strong alkaline conditions, leading to embrittlement and deterioration of polylactic acid fibers, leading to extreme strength deterioration, and therefore reduction cleaning cannot be performed under strong alkaline conditions. There was a problem that the color fastness to washing was further lowered.

  For this reason, Patent Document 3 proposes a reduction washing treatment at a low temperature of 70 ° C. or lower and an acidic condition after the dyeing treatment, but increases the fastness to dyeing and the fiber strength after the wet heat treatment to a satisfactory level. I couldn't.

JP 2003-105629 A Japanese Patent No. 3731432 JP 2001-355187 A

  The present invention has been made in view of the above-mentioned background, and the object thereof is a dyed fiber structure containing polylactic acid fibers, which is excellent in dyeing fastness and has a small decrease in fiber strength in a moist heat environment. It is an object to provide a method for producing a dyed fiber structure, a dyed fiber structure obtained by the production method, and a fiber product using the dyed fiber structure.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors obtained a fiber structure using a polylactic acid fiber having a high melting point, dyeing the fiber structure, and then performing a reduction cleaning treatment. The present inventors have found that a dyed fiber structure excellent in dyeing fastness and having a small decrease in fiber strength under a moist and heat environment can be obtained, and further intensive studies have been made to complete the present invention.

Thus, according to the present invention, “a method for producing a dyed fiber structure containing polylactic acid fibers that is subjected to a reduction cleaning treatment after dyeing the fiber structure A containing polylactic acid fibers,
A method for producing a dyed fiber structure containing polylactic acid fibers, wherein the polylactic acid fibers have a melting point of 195 ° C or higher. Is provided.

  At that time, the polylactic acid fiber was added in an amount of 0.001 per 100 parts by weight of (i) poly L-lactic acid (A component), (ii) poly D-lactic acid (B component), and (iii) A component and B component. It is preferably composed of a polylactic acid composition containing a phosphoric acid ester metal salt (component C) represented by the following formula (1) or (2) in an amount of 05 to 5 parts by weight.

式中、Ｒ_１は水素原子または炭素数１〜４のアルキル基を表し、Ｒ_２、Ｒ_３は各々独立に水素原子または炭素数１〜１２のアルキル基を表し、Ｍ_１はアルカリ金属原子またはアルカリ土類金属原子を表し、ｐは１または２を表す。

In the formula, _{R 1} represents a hydrogen atom or an alkyl group having 1 to 4 carbon _atoms, R 2, _{R 3} each independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, _{M 1} is or an alkali metal atom Represents an alkaline earth metal atom, and p represents 1 or 2.

式中、Ｒ_４、Ｒ_５およびＲ_６は、各々独立に水素原子または炭素数１〜１２のアルキル基を表し、Ｍ_２はアルカリ金属原子またはアルカリ土類金属原子を表し、ｐは１または２を表す。

In the formula, each of R ₄ , R ₅ and R ₆ independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, M ₂ represents an alkali metal atom or an alkaline earth metal atom, and p represents 1 or 2 Represents.

  The polylactic acid composition contains 0.1 to 5 parts by weight of a carboxyl terminal blocking agent per 100 parts by weight in total of the poly L-lactic acid component (A component) and the poly D-lactic acid component (B component). It is preferable. Moreover, it is preferable that a polyester fiber is contained in the fiber structure A as another fiber. In that case, it is preferable that this polyester fiber is a polyethylene terephthalate fiber.

  In the method for producing a dyed fiber structure containing the polylactic acid fiber of the present invention, the fiber structure A preferably has a woven or knitted structure. Moreover, it is preferable to perform the said dyeing | staining process at the temperature of 120 degreeC or more. Moreover, it is preferable to perform the said reduction | restoration washing process within the temperature of 60-98 degreeC in the reduction bath of pH 8-2.

  Moreover, according to this invention, the dyed fiber structure manufactured by the said manufacturing method is provided. At this time, after the dyed fiber structure was treated for 1 week in an environment of a temperature of 70 ° C. and a humidity of 90% RH, the fiber strength of the polylactic acid fiber contained in the dyed fiber structure was 0.5 cN. / Dtex or more is preferable. Further, it is preferable that the lightness index L value of the dyed fiber structure is 80 or less. Further, in such a dyed fiber structure, it is preferable that the fastness to washing of the fiber structure, measured by the AATCC IIA method, is 3 or more.

  Further, according to the present invention, a vehicle interior that is a sports garment, a nifoam garment, a shirt, a blouson, a pant, a coat, a car seat skin material, a floor material, or a ceiling material, comprising the dyed fiber structure. Materials such as materials, cups or pads, curtains or carpets or mats or furniture or upholstered interior goods, belts, nets, ropes, heavy cloth, bags, felts, filters, industrial materials, accessories, form straps, glasses Any textile product selected from the group consisting of wipes, dish wipes, mouse pads, stuffed toys, toys, hats, gloves, whiteboard cleaners, notebook covers, and accessories is provided.

  According to the present invention, a dyed fiber structure containing polylactic acid fibers, which is excellent in dyeing fastness and has a small decrease in fiber strength under a moist heat environment, and a method for producing the dyed fiber structure, A dyed fiber structure obtained by the production method and a fiber product using the dyed fiber structure are obtained.

Hereinafter, the present invention will be described in detail.
It is important that the polylactic acid fiber used in the present invention has a melting point of 195 ° C. or higher (preferably 195 to 260 ° C.). When the melting point is less than 195 ° C., a dyed fiber structure excellent in dyeing fastness and having a small decrease in fiber strength in a moist heat environment is not preferable. The melting point is the melting peak temperature measured with a differential scanning calorimeter (DSC). When there are two or more melting peak temperatures, the highest temperature is taken as the melting point.

  Such polylactic acid fibers having a melting point of 195 ° C. or higher include (i) poly L-lactic acid (A component), (ii) poly D-lactic acid (B component), and (iii) total of A component and B component. Polylactic acid fibers comprising a polylactic acid composition containing 0.05 to 5 parts by weight of a phosphoric acid ester metal salt (component C) per 100 parts by weight are preferred.

  Here, the poly L-lactic acid (component A) mainly comprises L-lactic acid units. The L-lactic acid unit is a repeating unit derived from L-lactic acid. The poly L-lactic acid (component A) preferably contains 90 to 100 mol%, more preferably 95 to 100 mol%, and still more preferably 98 to 100 mol% of L-lactic acid units. Other repeating units include D-lactic acid units and units other than lactic acid. The D-lactic acid unit and the units other than lactic acid are preferably 0 to 10 mol%, more preferably 0 to 5 mol%, still more preferably 0 to 2 mol%.

  Examples of units other than lactic acid include hydroxycarboxylic acids such as glycolic acid, caprolactone, butyrolactone, propiolactone, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-propanediol, 1,5 -Propanediol, hexanediol, octanediol, decanediol, dodecanediol, aliphatic diols having 2 to 30 carbon atoms, succinic acid, maleic acid, adipic acid, aliphatic dicarboxylic acids having 2 to 30 carbon atoms, terephthalic acid And units derived from one or more monomers selected from aromatic diols such as isophthalic acid, hydroxybenzoic acid, and hydroquinone, and aromatic dicarboxylic acids.

The poly L-lactic acid (component A) preferably has crystallinity. The melting point is preferably 150 to 190 ° C, more preferably 160 to 190 ° C. If these conditions are satisfied, a stereocomplex crystal having a high melting point can be formed and the crystallinity can be increased.
In poly L-lactic acid (component A), the weight average molecular weight is preferably 50,000 to 300,000 (more preferably 100,000 to 250,000).

  On the other hand, the poly D-lactic acid (component B) is mainly composed of D-lactic acid units. The D-lactic acid unit is a repeating unit derived from D-lactic acid. The poly-D-lactic acid preferably contains 90 to 100 mol%, more preferably 95 to 100 mol%, and still more preferably 98 to 100 mol% of D-lactic acid units. Other repeating units include L-lactic acid units and units other than lactic acid. The L-lactic acid unit and the units other than lactic acid are preferably 0 to 10 mol%, more preferably 0 to 5 mol%, still more preferably 0 to 2 mol%.

  Examples of units other than lactic acid include hydroxycarboxylic acids such as glycolic acid, caprolactone, butyrolactone, propiolactone, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-propanediol, 1,5 -Propanediol, hexanediol, octanediol, decanediol, dodecanediol, aliphatic diols having 2 to 30 carbon atoms, succinic acid, maleic acid, adipic acid, aliphatic dicarboxylic acids having 2 to 30 carbon atoms, terephthalic acid And units derived from one or more monomers selected from aromatic diols such as isophthalic acid, hydroxybenzoic acid, and hydroquinone, and aromatic dicarboxylic acids.

Poly D-lactic acid (component B) preferably has crystallinity. The melting point is preferably 150 to 190 ° C, more preferably 160 to 190 ° C. If these conditions are satisfied, a stereocomplex crystal having a high melting point can be formed and the crystallinity can be increased.
In poly D-lactic acid (component B), the weight average molecular weight is preferably 50,000 to 300,000 (more preferably 100,000 to 250,000).

  Poly-L-lactic acid (component A) or poly-D-lactic acid (component B) can be produced by directly dehydrating condensation of L-lactic acid or D-lactic acid, or once dehydrating and cyclizing L-lactic acid or D-lactic acid. It can be produced by a method of ring-opening polymerization after making lactide. Catalysts used in these methods include divalent tin compounds such as tin octylate, tin chloride, and tin alkoxides, tetravalent tin compounds such as tin oxide, butyltin oxide, and ethyltin oxide, metal tin, zinc compounds, aluminum compounds, Examples thereof include calcium compounds and lanthanide compounds.

  The poly L-lactic acid (component A) and the poly D-lactic acid (component B) are preferably washed away with a polymerization catalyst used during the polymerization, or the catalytic activity is deactivated. A catalyst deactivator can be used to inactivate the catalyst activity.

As a catalyst deactivator, an organic ligand consisting of a group of chelate ligands having an imino group and capable of coordinating to a metal polymerization catalyst, a phosphorus oxoacid, a phosphorus oxoacid ester, and an organic phosphorus oxoacid compound represented by the formula (3) There may be mentioned at least one selected from the group. The catalyst deactivator is preferably blended in an amount of 0.3 to 20 equivalents, more preferably 0.4 to 15 equivalents, and even more preferably 0.5 to 10 equivalents per equivalent of the metal element in the catalyst at the end of the polymerization. .
_{X 1 -P (= O) m} (OH) n (OX 2) 2-n (3)
In the formula, m is 0 or 1, n is 1 or 2, and X ₁ and X ₂ each independently represent a hydrocarbon group optionally having a substituent having 1 to 20 carbon atoms. Examples of the hydrocarbon group include alkyl groups having 1 to 20 carbon atoms such as a methyl group, an ethyl group, a propyl group, and a butyl group.

  The metal ion content in poly L-lactic acid (component A) and poly D-lactic acid (component B) is preferably 20 ppm or less from the viewpoint of heat resistance and hydrolysis resistance of the fiber. The metal ion content is preferably such that the content of each metal selected from alkaline earth metals, rare earths, transition metals of the third period, aluminum, germanium, tin and antimony is 20 ppm or less.

Next, the phosphoric acid ester metal salt (component C) is a compound represented by the following formula (1) or (2). The phosphoric acid ester metal salt may be used alone or in combination.

In Formula (1), R ₁ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms represented by R ₁ include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, and an iso-butyl group. The
R _{2, R 3} each independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, sec-butyl group, iso-butyl group, tert-butyl group, amyl group, tert-amyl group, hexyl group, heptyl group, octyl group, iso-octyl group, tert-octyl group, 2-ethylhexyl group, nonyl group, iso-nonyl group, decyl group, iso-decyl group, tert-decyl group, An undecyl group, a dodecyl group, a tert-dodecyl group, etc. are mentioned.
M ₁ represents an alkali metal atom such as Na, K or Li or an alkaline earth metal atom such as Mg or Ca. p represents 1 or 2.

Preferable examples of the phosphoric acid ester metal salt represented by the formula (1) include those in which R ₁ is a hydrogen atom and R ₂ and R ₃ are both tert-butyl groups.

In the formula (2), R ₄ , R ₅ and R ₆ each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, sec-butyl group, iso-butyl group, tert-butyl group, amyl group, tert-amyl group, hexyl group, heptyl group, octyl group, iso-octyl group, tert-octyl group, 2-ethylhexyl group, nonyl group, iso-nonyl group, decyl group, iso-decyl group, tert-decyl group, An undecyl group, a dodecyl group, a tert-dodecyl group, etc. are mentioned.
M ₂ represents an alkali metal atom such as Na, K or Li or an alkaline earth metal atom such as Mg or Ca. p represents 1 or 2.
Preferable examples of the phosphoric ester metal salt represented by the formula (2) it is, for _example, R 4, _{R 6} is a methyl group, _{R 5} may be mentioned those of tert- butyl group. Examples of the phosphoric acid ester metal salt include trade names, NA-11 and NA-71, manufactured by ADEKA Corporation. The phosphoric acid ester metal salt can be synthesized by a known method.

As described in JP-A-2003-192884, the compound represented by the formula (1) or (2) is a compound known as a crystal nucleating agent for polylactic acid. However, in the present invention, M ₁ and M ₂ of the formula (1), wherein (2) is characterized in that an alkali metal atom or alkaline earth metal atom. When M ₁ and M _{2 in the} formulas (1) and (2) are other metals such as aluminum, the heat resistance of the compound itself is low, and a sublimate is generated during spinning, which makes it difficult to spin. There is a case.

  The phosphoric acid ester metal salt (component C) preferably has an average primary particle size of 0.01 to 10 μm, more preferably 0.05 to 7 μm. It is industrially difficult to make the particle size smaller than 0.01 μm, and it is not necessary to make it so small. On the other hand, if it is larger than 10 μm, the frequency of yarn breakage increases during spinning and drawing.

  The content of the phosphoric acid ester metal salt (component C) is 0.01 to 5 parts by weight, preferably 0.005 parts per 100 parts by weight in total of poly L-lactic acid (component A) and poly D-lactic acid (component B). 05 to 5 parts by weight, more preferably 0.05 to 4 parts by weight, particularly preferably 0.1 to 3 parts by weight. If the amount is less than 0.01 parts by weight, the desired effect is hardly recognized. On the other hand, if it is used in an amount of more than 5 parts by weight, it is not preferable because thermal decomposition or fiber breakage may occur during fiber formation.

  The ratio of poly L-lactic acid (component A) to poly D-lactic acid (component B) is component A / component B (weight), preferably 40 / 60-60 / 40, more preferably 45 / 55-55. / 45, more preferably 50/50.

  For mixing the A component, the B component, and the C component, various conventionally known methods can be used. For example, the A component, the B component, and the C component can be mixed with a tumbler, a V-type blender, a super mixer, a nauta mixer, a Banbury mixer, a kneading roll, a monoaxial or biaxial extruder, and the like.

  The polylactic acid composition thus obtained can be melt-mixed and transferred to the spinning device as it is or via a metering pump or the like. The temperature for melting and mixing is preferably higher than the melting point of the resulting stereocomplex polylactic acid, and preferably higher than 220 ° C. Further, it may be once pelletized and then supplied to the spinning device. The pellet length is preferably 1 to 7 mm, the major axis is 3 to 5 mm, and the minor axis is 1 to 4 mm. The pellet shape is preferably uniform. The pelletized composition can be transferred to a spinning device using a normal melt extruder such as a pressure melter type or a single-screw or twin-screw extruder type. In forming the stereocomplex crystal, it is important to sufficiently mix the A component and the B component, and it is particularly preferable to mix them under shear stress.

  In the polylactic acid composition, a carboxyl group end-capping agent having a specific functional group can be suitably applied as a wet heat resistance improver. As such a carboxyl terminal blocking agent, it is preferable to use at least one compound selected from an epoxy compound, a carbodiimide compound, an oxazoline compound, an oxazine compound, and an isocyanate compound. By containing the terminal carboxyl group terminal blocking agent, not only the effect of improving the heat and moisture resistance can be improved, but also a fiber excellent in spinnability, mechanical properties, heat resistance and durability can be obtained.

  Here, as an epoxy compound, a glycidyl ether compound, a glycidyl ester compound, a glycidyl amine compound, a glycidyl imide compound, a glycidyl amide compound, and an alicyclic epoxy compound can be preferably used.

  Examples of the carbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, octyldecylcarbodiimide, di-t-butylcarbodiimide, t-butylisopropylcarbodiimide, dibenzylcarbodiimide, N-octacarbodiimide, -N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, di-o-toluylcarbodiimide, di-p-toluylcarbodiimide, bis (p-nitrophenyl) carbodiimide, Bis (p-aminophenyl) carbodiimide, bis (p-hydroxyphenyl) carbodiimide, bis (p- Lorophenyl) carbodiimide, bis (o-chlorophenyl) carbodiimide, bis (o-ethylphenyl) carbodiimide, bis (p-ethylphenyl) carbodiimide bis (o-isopropylphenyl) carbodiimide, bis (p-isopropylphenyl) carbodiimide, bis (o -Isobutylphenyl) carbodiimide, bis (p-isobutylphenyl) carbodiimide, bis (2,5-dichlorophenyl) carbodiimide, p-phenylenebis (o-toluylcarbodiimide), p-phenylenebis (cyclohexylcarbodiimide, p-phenylenenebis ( p-chlorophenylcarbodiimide), 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide, hexamethylenebis (cyclohexylcarbodiimide), Tylene bis (phenylcarbodiimide), ethylene bis (cyclohexylcarbodiimide), bis (2,6-dimethylphenyl) carbodiimide, bis (2,6-diethylphenyl) carbodiimide, bis (2-ethyl-6-isopropylphenyl) carbodiimide, bis ( 2-butyl-6-isopropylphenyl) carbodiimide, bis (2,6-diisopropylphenyl) carbodiimide, bis (2,6-di-t-butylphenyl) carbodiimide, bis (2,4,6-trimethylphenyl) carbodiimide, Bis (2,4,6-triisopropylphenyl) carbodiimide, bis (2,4,6-tributylphenyl) carbodiimide, di-β-naphthylcarboimide, N-tolyl-N′-cyclohexylcarbosiimide, N— Thrill Mono- or di-carbodiimide compounds such as N'- phenyl carbocyclylalkyl imide and the like.

  Of these, bis (2,6-diisopropylphenyl) carbodiimide and 2,6,2 ', 6'-tetraisopropyldiphenylcarbodiimide are preferred from the viewpoints of reactivity and stability. Of these, industrially available dicyclohexylcarbodiimide and diisopropylcarbodiimide are also suitable.

  Also, poly (1,6-cyclohexanecarbodiimide), poly (4,4′-methylenebiscyclohexylcarbodiimide), poly (1,3-cyclohexylenecarbodiimide), poly (1,4-cyclohexylenecarbodiimide), poly (4 , 4′-diphenylmethanecarbodiimide), poly (3,3′-dimethyl-4,4′-diphenylmethanecarbodiimide), poly (naphthylenecarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly Examples thereof include polycarbodiimides such as (p-tolylcarbodiimide), poly (diisopropylcarbodiimide), poly (methyldisopropylphenylenecarbodiimide), and poly (triethylphenylenecarbodiimide).

  As the commercially available polycarbodiimide compound, for example, “Carbodilite” marketed by Nisshinbo Co., Ltd. can be used. Specifically, “Carbodilite” LA-1 sold as a polylactic acid resin modifier, or polyester “Carbodilite” HMV-8CA sold as a resin modifier can be exemplified.

  A carbodiimide compound can also be manufactured by a conventionally well-known method. For example, it can be produced by subjecting an organic isocyanate to a decarboxylation condensation reaction in a solvent-free or inert solvent at a temperature of 70 ° C. or higher using an organic phosphorus compound or an organometallic compound as a catalyst. The polycarbodiimide compound may be a conventionally known method for producing a polycarbodiimide compound, for example, US Pat. No. 2,941,956, Japanese Examined Patent Publication No. 47-33279, J. Pat. Org. Chem. 28, 2069-2075 (1963), Chemical Review 1981, Vol. 81 no. 4, p619-621 and the like.

  The content of the carboxyl group terminal blocking agent is preferably 0.1 to 5.0 parts by weight, more preferably 0.5 to 2.0 parts by weight, per 100 parts by weight of the polylactic acid composition. A polylactic acid fiber containing a carboxyl group end-capping agent in such a range has a molecular weight retention of 95% or more after treatment for 30 minutes in boiling water at 100 ° C., and a more preferable fiber can be obtained.

  In the present invention, it is preferable that the polylactic acid fiber has a stereoification ratio of 90% or more by wide angle X-ray diffraction (XRD) measurement. The fiber strength is preferably 2.3 cN / dtex or more in terms of tensile strength. Moreover, it has a single melting peak in a differential scanning calorimeter (DSC) measurement, and it is preferable that this melting peak temperature is 195 degreeC or more.

  Such polylactic acid fiber can be produced by, for example, the following method. That is, the polylactic acid composition is melted with an extruder type or pressure melter type melt extruder, weighed with a gear pump, filtered in a pack, and then monofilament, multifilament, etc. from a nozzle provided on the base Discharged and spun as. In this case, any shape can be used as long as the shape of the die is a different type (including a hollow round shape). The number of discharge holes is not particularly limited. The discharged yarn is immediately cooled and solidified, then converged, added with oil, and wound. The spinning speed is not particularly limited, but a range of 300 to 5000 m / min is preferable because a stereocomplex crystal is easily formed. In particular, from the viewpoint of drawability, a spinning speed at which the stereo ratio of the undrawn yarn is 0% is preferable. The wound undrawn yarn is then subjected to a drawing step, but the spinning step and the drawing step are not necessarily separated from each other. Even if a direct spinning drawing method is used in which the drawing is continued without being wound once after spinning. Good. Such undrawn yarn is substantially amorphous as measured by wide-angle X-ray diffraction. Further, when the differential scanning calorimeter (DSC) measurement is performed, at least two endothermic peaks of the low-temperature crystal melting phase (A) and the high-temperature crystal melting phase (B) are not exhibited, and the stereocomplex crystal is substantially A single melting peak is shown. Such melting peak temperature is 195 ° C. or higher. That is, it is estimated that the undrawn yarn forms an amorphous stereocomplex but does not contain a poly L-lactic acid phase and / or a poly D-lactic acid phase capable of forming a low-temperature crystal phase. These characteristics are useful properties that have never been expected in the past due to the fact that the fiber contains a phosphoric acid ester metal salt (component C).

Not having a crystalline phase of poly-L-lactic acid or poly-D-lactic acid at the stage of undrawn yarn is effective for obtaining a high stereo ratio after the subsequent drawing step.
The stretching may be one-stage or multi-stage stretching of two or more stages. From the viewpoint of producing a high-strength fiber, the draw ratio is preferably 3 times or more, more preferably 4 times or more, and further preferably 3 to 10 times. It is. However, if the draw ratio is too high, the fiber is devitrified and whitened, so that the strength of the fiber is lowered. Preheating for stretching can be performed by using a flat plate or pin-shaped contact heater, non-contact heater, heating medium bath, etc., in addition to raising the temperature of the roll. The stretching temperature is preferably 70 to 140 ° C, more preferably 80 to 130 ° C. Even in the drawn yarn, substantially no low-temperature crystal melt phase (A) is observed, and only a single melt peak of the high-temperature crystal melt phase (B) is observed. Further, the melting start temperature of the high-temperature crystal melting phase (B) of the drawn yarn is 190 ° C. or higher, preferably 200 ° C. or higher. In addition, the stereoization rate (Sc rate) obtained from the integrated intensity of the stereocomplex crystal diffraction peak by wide-angle X-ray diffraction measurement of the drawn yarn is at a high level of 90% or more.

  Furthermore, it is preferable to heat-treat the drawn yarn. The heat treatment is performed at 170 to 220 ° C. (preferably 180 to 200 ° C.). The heat treatment is preferably performed under tension. The heat treatment can be performed with a hot roller, a contact heater, a non-contact hot plate or the like. By heat-treating, it is possible to obtain a fiber having a high stereo ratio, excellent heat resistance and iron resistance, and a strength of 2.3 cN / dTex or more.

  The fiber structure A used in the production method of the present invention is a fiber structure containing the polylactic acid fiber. Here, as the form of the polylactic acid fiber, the single yarn fineness is 0.01 to 20 dtex (more preferably 0.1 to 7 dtex), the total fineness is 30 to 500 dtex, and the number of filaments is in the range of 20 to 200. It is preferable that it is a multifilament (long fiber). The single fiber cross-sectional shape of the polylactic acid fiber is not particularly limited, and may be any of a normal round cross section, a round hollow cross section, a triangular cross section, a square cross section, a flat cross section, and a constricted flat cross section. The yarn may be subjected to twisting, air processing, false twist crimping, or the like. In particular, when the polylactic acid fiber is twisted at about 100 to 600 T / m, not only the wear resistance of the fabric is improved, but also the handleability during production of the fiber structure is improved. Moreover, although it is preferable to comprise a fabric using only the said thread | yarn (polylactic acid fiber), if it is 60 weight% or less with respect to the fabric weight, other fibers, such as a polyester fiber, may be contained. . In that case, a normal polyethylene terephthalate fiber is suitable as the polyester fiber.

  Further, the structure of the fiber structure A is not particularly limited, but is preferably a woven fabric or a knitted fabric knitted or woven by a normal loom or knitting machine. Of course, yarns, stuffed cotton, non-woven fabrics, and fiber structures composed of matrix fibers and heat-bondable fibers may also be used. In this case, examples of the woven structure of the woven fabric include a three-layer structure such as plain weave, twill weave and satin weave, a change structure, a single double structure such as a vertical double weave and a horizontal double weave, and a vertical velvet. The type of knitted fabric may be a circular knitted fabric (weft knitted fabric) or a freshly knitted fabric. Preferred examples of the structure of the circular knitted fabric (weft knitted fabric) include flat knitting, rubber knitting, double-sided knitting, pearl knitting, tuck knitting, floating knitting, one-sided knitting, lace knitting, and bristle knitting. Examples include single denby knitting, single atlas knitting, double cord knitting, half tricot knitting, back hair knitting, jacquard knitting, and the like. The number of layers may be a single layer or a multilayer of two or more layers. Furthermore, it may be a napped fabric composed of napped portions made of cut piles and / or loop piles and a ground tissue portion.

  In the production method of the present invention, the fiber structure A is dyed. The dyeing process is not particularly limited, and may be a dyeing process using a normal disperse dye. For example, when the fiber structure A contains aromatic polyester fibers such as polyethylene terephthalate fibers as other fibers, 120 ° C. or higher (preferably in a dye aqueous solution containing a leveling agent, a pH adjuster, etc. in addition to a disperse dye. Is preferably performed at a temperature of 120 to 135 ° C. for 20 to 40 minutes. The dye used for dyeing is preferably an azo-based disperse dye having good washing fastness, but is not particularly limited. Among these, disperse dyes that are easily decomposed in a cleaning treatment liquid described later are preferably disperse dyes having a diester group, azo disperse dyes, among which thiazole type and thiophene type, but are not particularly limited. Further examples include anthraquinone-based disperse dyes, benzodiphyranone-type disperse dyes, and disperse dyes having an alkylamine group.

  Subsequently, the fiber structure subjected to the dyeing process is subjected to a reduction cleaning process. At that time, it is preferable to perform a reduction cleaning treatment in a reducing bath having a pH of 8 to 2. In an alkaline region larger than ph8, the polylactic acid fiber may be hydrolyzed and the fiber strength may be reduced.

  Examples of the reducing agent include a tin-based reducing agent, Rongalite C, Rongalit Z, stannous chloride, a sulfine-based reducing agent, and hydrosulfite. The concentration of the reducing agent used is preferably 1 to 10 g / L, and the concentration may be selected according to the type of dye used, the dyeing concentration, and the reducing bath temperature. Although the processing temperature of a reducing bath is not specifically limited, The range of 60-98 degreeC is preferable, and the processing time is 10 to 40 minutes.

  Further, in the treatment in the reducing bath, as a fiber swelling agent, generally used carriers such as chlorobenzene carrier, methylnaphthalene carrier, orthophenylphenol carrier, aromatic ether carrier, aromatic ester A carrier or the like may be used. Examples of the fiber swelling agent include polyoxyethylene alkyl allyl ether, polyoxyethylene alkyl amine, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl amine ether, polyoxyethylene alkyl allyl ether, polyoxyethylene alkyl amine, polyoxyethylene alkyl phenol ether, Examples include, but are not limited to, ethylene alkyl benzyl ammonium chloride and alkyl picolinium chloride.

  According to the above manufacturing method, since the reduction cleaning treatment is performed in a weakly alkaline to acidic region having a pH of 8 or less, the lactic acid fiber is not hydrolyzed during the reduction cleaning treatment, and the excess dye on the fiber surface layer is reduced. Can be disassembled.

  The dyed fiber structure thus obtained is a fiber structure excellent in dyeing fastness and having a small decrease in fiber strength in a moist heat environment. At that time, after the dyed fiber structure was treated for 1 week in an environment of a temperature of 70 ° C. and a humidity of 90% RH, the polylactic acid fiber contained in the fiber structure had a fiber strength of 0.5 gr / dtex or more ( More preferably, it is preferably 3 to 10 gr / dtex). Moreover, in the dyed fiber structure, it is preferable that the lightness index L value is a dark color of 80 or less because the effect of the present invention is further manifested. Moreover, it is preferable that the wash fastness of the dyed fiber structure measured by the AATCC IIA method is grade 3 or higher.

  However, the strength in the present invention is “Tensilon” (trade name) manufactured by Orientic Corporation. Ten target single yarns (filaments) are randomly extracted from the fiber structure to be measured, and the length of the yarn sample is 50 mm (chuck) The strain-stress curve was measured under the conditions of an ambient temperature of 20 ° C. and a relative humidity of 65% under the conditions of an elongation length of 500 mm / min, and the strength (cN / piece) was determined from the stress and elongation at the breaking point. Thereafter, this strength is divided by the fineness to obtain fiber strength (cN / dtex). In addition, the treatment for one week at 70 ° C. × 90% RH is performed by using the constant temperature and humidity chamber LHU-112M manufactured by Tabai Espec Co., Ltd. and leaving the sample in the environment in the set device for one week. Shall be implemented.

  The dyed fiber structure of the present invention includes conventional flame retardant processing, water repellent processing, brushed processing, ultraviolet shielding or antibacterial agent, deodorant, insect repellent, phosphorescent agent, retroreflective agent, negative ion Various processings that impart functions such as a generator may be additionally applied.

  Next, the fiber product of the present invention is a fiber product using the dyed fiber structure. Such textile products include sports apparel, nifoam apparel, shirts, blousons, pants, coats, car seat covering materials, flooring materials, ceiling materials such as clothing materials such as cups and pads, curtains, carpets and mats. , Furniture, interior items such as chairs, industrial materials such as belts, nets, ropes, heavy cloth, bags, felts, filters, accessories, form straps, glasses, tableware, mouse pads, stuffed animals, toys, hats , Small items such as gloves, whiteboard cleaner, notebook cover. Such a textile product contains the dyed fiber structure, so that it exhibits excellent washing fastness and at the same time the strength of the fibers contained in the garment.

  Hereinafter, although the present invention is explained using an example, the present invention is not limited to this example. In addition, the physical property in an Example was measured with the following method.

(1) Weight average molecular weight (Mw)
The weight average molecular weight of the polymer was determined by GPC (column temperature 40 ° C., chloroform) in comparison with a polystyrene standard sample.

(2) Stereo conversion rate (Sc conversion rate)
An X-ray diffraction pattern was recorded on an imaging plate by the transmission method using a ROTA FLEX RU200B type X-ray diffractometer manufactured by RIKEN. In the obtained X-ray diffraction pattern, a diffraction intensity profile in the equator direction is obtained. Here, the integrated intensity of each diffraction peak derived from the stereocomplex crystal appearing in the vicinity of 2θ = 12.0 °, 20.7 °, and 24.0 °. Was obtained from the total intensity ΣI _SCi and the integrated intensity I _HM of the diffraction peak derived from the homocrystal appearing in the vicinity of 2θ = 16.5 ° in accordance with the following formula. Incidentally, as shown in FIG. 1, ΣI _SCi and I _HM were estimated by subtracting diffuse scattering due to background or amorphous in the diffraction intensity profile in the equator direction.
X-ray source: Cu-Kα ray (confocal mirror)
Output: 45kV x 70mA
Slit: 1mmΦ ~ 0.8mmΦ
Camera length: 120mm
Integration time: 10 minutes Sample: 3cm length, 35mg
Sc conversion rate = ΣI _SCi / (ΣI _SCi + I _HM ) × 100
Here, ΣI _SCi = I _SC1 + I _SC2 + I _SC3
I _SCi (i = 1 to 3) is 2θ = 12.0 °, 20.7 °,
Integrated intensity of each diffraction peak around 24.0 °

(3) Melting point, crystal melting peak, crystal melting start temperature, crystal melting enthalpy measurement:
TA-2920 differential scanning calorimeter DSC manufactured by TA Instruments was used.
In the measurement, 10 mg of a sample was heated from room temperature to 260 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere. In the first scan, the homocrystal melting peak, homocrystal melting (starting) temperature, homocrystal melting enthalpy and stereocomplex crystal melting peak, stereocomplex crystal melting (starting) temperature and stereocomplex crystal melting enthalpy were determined.

(4) Washing fastness It measured by the following AATCCII-A method.
1) Test method: AATCC 61-1980IIA
2) Equipment and materials Roundometer: 40-44 rpm
2. Test bottle (stainless steel): 450-550ml
3. Stainless steel balls: Diameter 0.4mm 50 per bottle 4. Soap: Solid laundry soap (JIS K3302) additive-free (1 type)
5. Metasilicate Sodium _{(Na 2 SiO 3 · 5H 2} O)
6). Glacial acetic acid7. Flat iron 8. Centrifugal dehydrator or squeezer 3) Attached white cloth AATCC Multifibre No. 1
Weft: acetate, cotton, nylon, silk, rayon, wool warp: polyester (spun yarn)
4) Preparation of test piece One piece of fresh 15cm x 5cm wide test piece was collected, and four white sides were placed so that one 5cm x 5cm attached white cloth (multi-fiber No1) was in contact with the center of the test piece. Sew together with cotton thread. In the case of a knitted fabric, bleached muslin having a density of 80 (lines / 2.54 cm) × 80 (lines / 2.54 cm) of the same size as the test piece is used, and all four sides are sewn to the test piece, and the ends are wound during the test. To prevent.
5) Test operation 150 ml of a 0.2% sodium metasuccinate 0.2% solution is placed in a test bottle and 50 stainless hard balls are placed. After preheating to a temperature of 49 ° C., a composite test piece is placed, sealed and attached to a rotating machine shaft, and rotated at a temperature of 49 ° C. for 45 minutes. Next, immediately remove the composite specimen from the test bottle without cooling and wash it with 100 ml of warm water (40 ° C.) for 1 minute, then wash twice with 100 ml of water (27 ° C.) for 1 minute. Or it spin-dry | dehydrates with a squeezer and press-drys with a flat iron with a temperature of 135 to 150 degreeC, with a test piece and an attached white cloth attached.
6) Judgment Judgment of contamination of the multi-fiber No1 is performed according to JISL0801 on the gray scale of the nylon part.

(5) L value The L value of the knitted fabric after dyeing was measured on the surface of the fabric with a spectroscopic light device (Gretag MacBeth Color-Eye 7000A). The L value indicates the lightness. The larger the value, the higher the lightness. The closer to 100, the lighter the color is, the closer to white, the closer to 0, the darker the color.

(6) Fiber strength (g / dtex)
For the strength in the present invention, “Tensilon” (trade name) manufactured by Orientic Co., Ltd. was used, 10 target single yarns (filaments) were randomly extracted from the fiber structure to be measured, and a yarn sample length of 50 mm (chuck length) The strain-stress curve was measured under the conditions of an elongation rate of 500 mm / min under an atmosphere temperature of 20 ° C. and a relative humidity of 65%, and the strength (g / piece) was determined from the stress and elongation at the breaking point. This strength was divided by the fineness to obtain fiber strength (g / dtex). In addition, each value used the average value of 10 times of measured values.

[Production Example 1] (Production of poly L-lactic acid)
To 100 parts by weight of L-lactide (manufactured by Musashino Chemical Laboratory, Inc., 100% optical purity), 0.005 part by weight of octyltinate was added, and the reaction was carried out at 180 ° C. in a reactor equipped with a stirring blade in a nitrogen atmosphere. After reacting for 2 hours, phosphoric acid equivalent to 1.2 times the amount of tin octylate was added, and then the remaining lactide was removed at 13.3 kPa to obtain chips to obtain poly L-lactic acid.
The obtained L-lactic acid had a weight average molecular weight of 150,000, a glass transition point (Tg) of 63 ° C., and a melting point of 180 ° C.

[Production Example 2] (Production of poly-D-lactic acid)
To 100 parts by weight of D-lactide (manufactured by Musashino Chemical Laboratory, Inc., 100% optical purity), 0.005 part by weight of tin octylate was added, and the reactor was stirred at 180 ° C. with a stirring blade in a nitrogen atmosphere. After reacting for 2 hours, phosphoric acid equivalent to 1.2 times the amount of tin octylate was added, and then the remaining lactide was removed at 13.3 kPa to obtain chips. Poly D-lactic acid was obtained. The weight average molecular weight was 150,000, the glass transition point (Tg) was 63 ° C., and the melting point was 180 ° C.

[Production Example 3] (Production of stereocomplex polylactic acid resin)
50 parts by weight of each of the poly L-lactic acid obtained in Production Example 1 and the poly D-lactic acid in Production Example 2, and phosphate metal salt (ADEKA (former: Asahi Denka Kogyo Co., Ltd.) ADK STAB NA-11) ) 0.5 parts by weight was melt-kneaded at 230 ° C., and 0.7 parts by weight of Nisshinbo Carbodilite LA-1 as the carbodiimide per 100 parts by weight of the total of poly L-lactic acid and poly D-lactic acid was supplied first. The mixture was supplied from the mouth and kneaded and extruded at a cylinder temperature of 230 ° C., and the strand was taken into a water tank and chipped with a chip cutter to obtain a stereocomplex polylactic acid resin. Mw of the obtained stereocomplex polylactic acid resin was 135,000, melting | fusing point (Tm) was 224 degreeC, and the stereoification rate was 100%.

[Example 1]
The stereocomplex polylactic acid resin obtained in Production Example 3 was dried at 110 ° C. for 2 hours and at 150 ° C. for 5 hours to give a moisture content of the resin of 80 ppm, and then a spinneret having 36 holes of 0.27 φmm was formed. The undrawn yarn was wound up at a speed of 500 m / min after spinning at a spinning temperature of 255 ° C. and a discharge rate of 8.35 g / min. The wound undrawn yarn was drawn 4.9 times with a drawing machine at 80 ° C. by preheating to wind the drawn yarn, and then heat treated at 180 ° C. The processability in the spinning process and the drawing process is good, and the wound drawn yarn is a multifilament having a fineness of 167 dTex / 36 fil, a strength of 3.6 cN / dTex, an elongation of 35%, and a single in DSC measurement. The melting peak temperature (melting point) was 224 ° C., and the stereo ratio was 100%.
Two obtained stereocomplex polylactic acid filaments were combined and twisted at 160 T / m, then placed on warps and wefts to weave a twill woven fabric, and then the fabric was heated to a temperature of 150 ° C. After 2 minutes of dry heat setting, dyeing was performed for 30 minutes at a temperature of 120 ° C. using a liquid flow dyeing machine. In that case, dyeing | staining and the reduction | restoration washing process were implemented using the following disperse dyes.

(Disperse dye name)
C. I. Disperse Blue 79 1% owf
The resulting dyed product was washed in the following reducing bath (pH 5.5).
Bath ratio; 1:20
Temperature × time; 120 ° C. × 30 minutes Reduction bath composition and cleaning conditions:
Thiourea dioxide 1g / l
Bath ratio; 1:20
Temperature × time: 70 ° C. × 15 minutes Then, after drying at a temperature of 130 ° C. for 10 minutes, a dry heat setting at a temperature of 160 ° C. for 2 minutes was performed. In the dyed fiber structure thus treated, the L value is 38, the fastness to washing is 4th grade, and the fiber after treatment for 1 week at 70 ° C. × 90% RH of the stereocomplex lactic acid fiber contained in the fabric. The strength was 1.8 cN / dtex (300 g / piece). Next, uniform garments, vehicle interior materials (car seat skin materials), and interior goods (chair upholstery) were obtained using the woven fabric, and were excellent in fastness to washing and durability.

[Example 2]
In Example 1, it carried out similarly to Example 1 except changing content of a phosphoric acid ester metal salt into 0.1 weight part. The obtained dyed fiber structure had an L value of 38, a fastness to washing of 4th grade, and a stereocomplex lactic acid fiber contained in the woven fabric having a fiber strength of 1. after treatment for 1 week at 70 ° C. × 90% RH. It was 8 cN / dtex (300 g / book). Next, uniform garments, vehicle interior materials (car seat skin materials), and interior goods (chair upholstery) were obtained using the woven fabric, and were excellent in fastness to washing and durability.

[Example 3]
In Example 1, it carried out similarly to Example 1 except changing content of a phosphoric acid ester metal salt into 1.0 weight part. The obtained dyed fiber structure had an L value of 38, a fastness to washing of 4 grade, and a stereocomplex lactic acid fiber contained in the fabric having a fiber strength of 1. after treatment for 1 week at 70 ° C. × 90% RH. It was 8 cN / dtex (300 g / book). Next, uniform garments, vehicle interior materials (car seat skin materials), and interior goods (chair upholstery) were obtained using the woven fabric, and were excellent in fastness to washing and durability.

[Comparative Example 1]
In Example 1, it carried out similarly to Example 1 except using the poly L-lactic acid obtained in manufacture example 1 instead of the stereocomplex polylactic acid resin. The DSC measurement of the drawn yarn had a single melting peak, and the melting peak temperature (melting point) was 180 ° C. The obtained woven fabric had a fiber strength of 0.05 cN / dtex (8 g / piece) after being treated at 70 ° C. × 90% RH for 1 week, and it was difficult to maintain the structure of the woven fabric.

[Reference Example 1]
As a phosphoric acid ester metal salt, aluminum bis (2,2′-methylenebis (4,6-ditertiarybutylphenyl) phosphate) hydroxide (ADEKA STAB NA-21 manufactured by ADEKA Corporation (formerly Asahi Denka Kogyo Co., Ltd.)) When the same operation as in Example 1 was performed except that 0.5 part by weight was used, a sublimation product was vigorously generated during spinning, and it was difficult to perform spinning.

[Example 4]
In Example 1, it carried out similarly to Example 1 except changing content of a phosphoric acid ester metal salt into 0 weight part. The DSC measurement of the drawn yarn had a single melting peak, and the melting peak temperature (melting point) was 224 ° C. The obtained woven fabric had a fiber strength of 0.05 cN / dtex (8 g / piece) after being treated at 70 ° C. × 90% RH for one week, and it was somewhat difficult to maintain the structure of the woven fabric.

[Reference Example 2]
In Example 1, it carried out similarly to Example 1 except implementing a reduction washing process on the strong alkali conditions of ph11. In the obtained woven fabric, the fiber strength after one week treatment at 70 ° C. × 90% RH was 0.3 cN / dtex (50 g / piece), and it was easily broken, and the structure of the woven fabric could not be maintained.

  According to the present invention, a dyed fiber structure containing polylactic acid fibers, which is excellent in dyeing fastness and has a small decrease in fiber strength under a moist heat environment, and a method for producing the dyed fiber structure, A dyed fiber structure obtained by the production method and a fiber product using the dyed fiber structure are provided, and its industrial value is extremely large.

In an Example, an example of the diffraction intensity profile of the equatorial direction for calculating | requiring a stereoization rate (Sc rate) is shown.

Claims (13)

  A method for producing a dyed fiber structure, comprising subjecting a fiber structure A containing a polylactic acid fiber having a melting point of 195 ° C. or more to a dyeing treatment, followed by a reduction cleaning treatment. The polylactic acid fiber is 0.05 to 5 per 100 parts by weight in total of (i) poly L-lactic acid (A component), (ii) poly D-lactic acid (B component) and (iii) A component and B component. The manufacturing method of the dyed fiber structure of Claim 1 which consists of a polylactic acid composition containing the phosphate metal salt (C component) represented by a following formula (1) or (2) of a weight part.

In the formula, _{R 1} represents a hydrogen atom or an alkyl group having 1 to 4 carbon _atoms, R 2, _{R 3} each independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, _{M 1} is or an alkali metal atom Represents an alkaline earth metal atom, and p represents 1 or 2.

In the formula, each of R ₄ , R ₅ and R ₆ independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, M ₂ represents an alkali metal atom or an alkaline earth metal atom, and p represents 1 or 2 Represents.   The polylactic acid composition contains 0.1 to 5 parts by weight of a carboxyl terminal blocking agent per 100 parts by weight in total of a poly L-lactic acid component (A component) and a poly D-lactic acid component (B component). The method for producing a dyed fiber structure according to claim 2.   The manufacturing method of the dyed fiber structure in any one of Claims 1-3 in which a polyester fiber is contained in the fiber structure A as another fiber.   The method for producing a dyed fiber structure according to claim 4, wherein the polyester fiber is a polyethylene terephthalate fiber.   The method for producing a dyed fiber structure according to any one of claims 1 to 5, wherein the fiber structure A has a woven structure or a knitted structure.   The method for producing a dyed fiber structure according to any one of claims 1 to 6, wherein the dyeing treatment is performed at a temperature of 120 ° C or higher.   The method for producing a dyed fiber structure according to any one of claims 1 to 7, wherein the reduction cleaning treatment is performed in a reduction bath having a pH of 8 to 2 within a temperature range of 60 to 98 ° C.   A dyed fiber structure produced by the production method according to claim 1.   The fiber strength of the polylactic acid fiber contained in the fiber structure is 0.5 cN / dtex or more after treating the dyed fiber structure in an environment of a temperature of 70 ° C. and a humidity of 90% RH for 1 week. Item 10. The dyed fiber structure according to Item 9.   The dyed fiber structure according to claim 9 or 10, wherein the lightness index L value of the dyed fiber structure is 80 or less.   The dyed fiber structure according to any one of claims 9 to 11, wherein the fastness to washing of the dyed fiber structure measured by the AATCC IIA method is grade 3 or higher.   A vehicle which is a sports garment, a nifoam garment, a shirt, a blouson, a pant, a coat, a car seat skin material, a floor material, or a ceiling material, comprising the dyed fiber structure according to any one of claims 9 to 12. Interior materials, clothing materials that are cups or pads, interior items that are curtains or carpets or mats or furniture or chairs, belts, nets, ropes, heavy cloth, bags, felts, filters, industrial materials, accessories, form straps, Any textile product selected from the group consisting of glasses wipes, tableware wipes, mouse pads, stuffed toys, toys, hats, gloves, whiteboard cleaners, notebook covers, and accessories.

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