JP5571464B2 - Water-absorbing polylactic acid fiber structure and fiber product - Google Patents

Description

  The present invention relates to a water-absorbing polylactic acid fiber structure and a fiber product having practical heat resistance and durability, and particularly improved hydrolysis resistance.

  In recent years, with increasing awareness of the environment on a global scale, polylactic acid synthesized from raw materials derived from plant-derived components has attracted attention. Polylactic acid is a polymer made from lactic acid obtained by fermenting starch or cellulose extracted from plants. Among plant-derived polymers, the balance of mechanical properties, heat resistance, and cost is excellent. Development of resin products, fibers, films, sheets, and the like using this has been performed. Among these, polylactic acid fibers have been developed for application to clothing, interiors such as curtains and carpets, vehicle interiors, and industrial materials. (For example, refer to Patent Document 1 and Patent Document 2).

It is also known to impart water absorption by subjecting a polylactic acid fiber structure to water absorption processing (see, for example, Patent Document 3). However, such a polylactic acid fiber structure has a problem that the fiber strength of the polylactic acid fiber contained in the fiber structure is low although it is excellent in water absorption.
In addition, it is known from Patent Documents 4 and 5 that the water absorption rate is increased by partially attaching a water repellent to the fiber structure.
However, polylactic acid fibers are susceptible to hydrolysis and thus have a problem that their product life is short. In particular, in the water-absorbing polylactic acid fiber structure, even if the water absorption is increased, the structure is easily subjected to hydrolysis, so that improvement has been demanded.

  In order to solve this problem, Patent Documents 6 and 7 propose polylactic acid in which hydrolysis resistance is improved by adding a carbodiimide compound or the like. However, when the carbodiimide compound used is used as an end-capping agent for a polymer compound, the compound having an isocyanate group is liberated as the carbodiimide compound binds to the end of polylactic acid, generating a unique odor of the isocyanate compound. However, deteriorating the working environment has been a problem.

JP 2003-105629 A Japanese Patent No. 3731432 JP 2005-82900 A JP 2007-162150 A JP 2009-174069 A JP 2009-256837 A JP 2009-256838 A

  The object of the present invention is to solve the problems of the prior art described above, improve hydrolysis resistance, and do not generate a free isocyanate compound when melted. Is to provide.

  As a result of intensive studies on the improvement of the abrasion resistance and hydrolysis resistance of the polylactic acid-based fiber and the improvement of the working environment, the present inventors have reacted with the polymer chain ends of the polylactic acid polymer. However, the present invention has been completed by finding that the above object can be achieved by a composition containing a carbodiimide compound having a specific structure that does not liberate an isocyanate compound.

That is, the object of the present invention is to
A polylactic acid fiber structure including a polylactic acid fiber containing a compound containing a cyclic structure in which one polylactic acid and one carbodiimide group and the first nitrogen and the second nitrogen are bonded by a bonding group is subjected to water absorption processing. Achieved by the water-absorbing polylactic acid fiber structure and fiber product.

According to the present invention, it is possible to provide a water-absorbing polylactic acid fiber structure and a fiber product having improved hydrolysis resistance.
Furthermore, the terminal of polylactic acid can be sealed with a carbodiimide compound without releasing the isocyanate compound. As a result, the generation of malodor due to the free isocyanate compound can be suppressed, and the working environment can be improved.

  Moreover, when the end of polylactic acid is sealed with a cyclic carbodiimide compound, an isocyanate group is formed at the end of polylactic acid, and the reaction of the isocyanate group makes it possible to increase the molecular weight of polylactic acid. The cyclic carbodiimide compound also has an action of capturing a free monomer in polylactic acid and other compounds having an acidic group. Furthermore, according to the present invention, the cyclic carbodiimide compound has an advantage that it can be end-capped under milder conditions as compared with a linear carbodiimide compound that is usually used by having a cyclic structure.

The difference between the linear carbodiimide compound and the cyclic carbodiimide compound in the end-capping reaction mechanism is as described below.
When a linear carbodiimide compound (R ₁ —N═C═N—R ₂ ) is used as a carboxyl terminal blocking agent for polylactic acid, the reaction is represented by the following formula. When the linear carbodiimide compound reacts with a carboxyl group, an amide group is formed at the terminal of polylactic acid, and an isocyanate compound (R ₁ NCO) is released.

（式中、Ｗはポリ乳酸の主鎖である。）

(Wherein, W is the main chain of polylactic acid.)

  On the other hand, when a cyclic carbodiimide compound is used as a carboxyl terminal blocking agent for polylactic acid, the reaction is represented by the following formula. It can be seen that when the cyclic carbodiimide compound reacts with a carboxyl group, an isocyanate group (-NCO) is formed at the terminal of polylactic acid via an amide group, and the isocyanate compound is not liberated.

（式中、Ｗはポリ乳酸の主鎖であり、Ｑは、脂肪族基、脂環族基、芳香族基またはこれらの組み合わせである２〜４価の結合基である。）

(Wherein, W is the main chain of polylactic acid, and Q is an aliphatic group, alicyclic group, aromatic group, or a divalent to tetravalent linking group that is a combination thereof.)

The fiber cross section of the unusual cross-sectional shape which can be employ | adopted in this invention is shown typically. An example of a water repellent adhesion pattern that can be employed in the present invention (a pattern in which squares are continuous at corners) is schematically shown, and a black coating portion is a water repellent adhesion portion. An example (lattice pattern) of a water repellent adhesion pattern that can be employed in the present invention is schematically shown, and a black coating portion is a water repellent adhesion portion.

<Cyclic carbodiimide compound (component C)>
In the present invention, the cyclic carbodiimide compound (C component) has a cyclic structure. The cyclic carbodiimide compound may have a plurality of cyclic structures.
The cyclic structure has one carbodiimide group (—N═C═N—), and the first nitrogen and the second nitrogen are bonded by a bonding group. One cyclic structure has only one carbodiimide group. For example, when there are a plurality of cyclic structures in the molecule, such as a spiro ring, one cyclic structure bonded to a spiro atom is included in each cyclic structure. Needless to say, the compound may have a plurality of carbodiimide groups as long as it has a carbodiimide group. The number of atoms in the cyclic structure is preferably 8 to 50, more preferably 10 to 30, further preferably 10 to 20, and particularly preferably 10 to 15.

  Here, the number of atoms in the ring structure means the number of atoms that directly constitute the ring structure, and is, for example, 8 for an 8-membered ring and 50 for a 50-membered ring. This is because if the number of atoms in the cyclic structure is smaller than 8, the stability of the cyclic carbodiimide compound is lowered, and it may be difficult to store and use. From the viewpoint of reactivity, there is no particular restriction on the upper limit of the number of ring members, but cyclic carbodiimide compounds having more than 50 atoms are difficult to synthesize, and the cost may increase significantly. From this viewpoint, the number of atoms in the cyclic structure is preferably 10-30, more preferably 10-20, and particularly preferably 10-15.

The cyclic structure is preferably a structure represented by the following formula (1).

  In the formula, Q is a divalent to tetravalent linking group that is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, each of which may contain a hetero atom and a substituent. A heteroatom in this case refers to O, N, S, P. Two of the valences of this linking group are used to form a cyclic structure. When Q is a trivalent or tetravalent linking group, it is bonded to a polymer or other cyclic structure via a single bond, a double bond, an atom, or an atomic group.

The linking group may include a heteroatom and a substituent, each having a divalent to tetravalent carbon number of 1 to 20 aliphatic group, a divalent to tetravalent carbon number of 3 to 20 alicyclic group, A linking group which is a tetravalent aromatic group having 5 to 15 carbon atoms or a combination thereof and has a necessary number of carbon atoms to form the cyclic structure defined above is selected. Examples of combinations include structures such as an alkylene-arylene group in which an alkylene group and an arylene group are bonded.
The linking group (Q) is preferably a divalent to tetravalent linking group represented by the following formula (1-1), (1-2) or (1-3).

In the formula, Ar ¹ and Ar ² are each independently a 2- to 4-valent aromatic group having 5 to 15 carbon atoms which may contain a hetero atom and a substituent.

  As an aromatic group, each of which contains a hetero atom and may have a heterocyclic structure, an arylene group having 5 to 15 carbon atoms, an arenetriyl group having 5 to 15 carbon atoms, an arenetetra having 5 to 15 carbon atoms Yl group. Examples of the arylene group (divalent) include a phenylene group and a naphthalenediyl group. Examples of the arenetriyl group (trivalent) include a benzenetriyl group and a naphthalenetriyl group. Examples of the arenetetrayl group (tetravalent) include a benzenetetrayl group and a naphthalenetetrayl group. These aromatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

R ¹ and R ² each independently contain a heteroatom and a substituent, each having 2 to 4 valent aliphatic groups having 1 to 20 carbon atoms and 2 to 4 valent fatty acids having 3 to 20 carbon atoms A cyclic group, and a combination thereof, or a combination of the aliphatic group, the alicyclic group, and a divalent to tetravalent aromatic group having 5 to 15 carbon atoms.

  Examples of the aliphatic group include an alkylene group having 1 to 20 carbon atoms, an alkanetriyl group having 1 to 20 carbon atoms, and an alkanetetrayl group having 1 to 20 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, a dodecylene group, and a hexadecylene group. As the alkanetriyl group, methanetriyl group, ethanetriyl group, propanetriyl group, butanetriyl group, pentanetriyl group, hexanetriyl group, heptanetriyl group, octanetriyl group, nonanetriyl group, decantriyl group, dodecantriyl group, Examples include a hexadecantriyl group. As alkanetetrayl group, methanetetrayl group, ethanetetrayl group, propanetetrayl group, butanetetrayl group, pentanetetrayl group, hexanetetrayl group, heptanetetrayl group, octanetetrayl group, nonanetetrayl group Decanetetrayl group, dodecanetetrayl group, hexadecanetetrayl group and the like. These aliphatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

  Examples of the alicyclic group include a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkanetriyl group having 3 to 20 carbon atoms, and a cycloalkanetetrayl group having 3 to 20 carbon atoms. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, a cyclodecylene group, a cyclododecylene group, and a cyclohexadecylene group. As cycloalkanetriyl group, cyclopropanetriyl group, cyclobutanetriyl group, cyclopentanetriyl group, cyclohexanetriyl group, cycloheptanetriyl group, cyclooctanetriyl group, cyclononanetriyl group, cyclodecanetriyl group Group, cyclododecane triyl group, cyclohexadecane triyl group and the like. As cycloalkanetetrayl group, cyclopropanetetrayl group, cyclobutanetetrayl group, cyclopentanetetrayl group, cyclohexanetetrayl group, cycloheptanetetrayl group, cyclooctanetetrayl group, cyclononanetetrayl group, cyclodecanetetrayl group Yl group, cyclododecanetetrayl group, cyclohexadecanetetrayl group and the like. These alicyclic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

  As an aromatic group, each of which contains a hetero atom and may have a heterocyclic structure, an arylene group having 5 to 15 carbon atoms, an arenetriyl group having 5 to 15 carbon atoms, an arenetetra having 5 to 15 carbon atoms Yl group. Examples of the arylene group include a phenylene group and a naphthalenediyl group. Examples of the arenetriyl group (trivalent) include a benzenetriyl group and a naphthalenetriyl group. Examples of the arenetetrayl group (tetravalent) include a benzenetetrayl group and a naphthalenetetrayl group. These aromatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

X ¹ and X ² each independently contain a heteroatom and a substituent, each having a 2 to 4 valent aliphatic group having 1 to 20 carbon atoms and a 2 to 4 valent fatty acid having 3 to 20 carbon atoms It is a cyclic group, a divalent to tetravalent aromatic group having 5 to 15 carbon atoms, or a combination thereof.

  Examples of the aliphatic group include an alkylene group having 1 to 20 carbon atoms, an alkanetriyl group having 1 to 20 carbon atoms, and an alkanetetrayl group having 1 to 20 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, a dodecylene group, and a hexadecylene group. As the alkanetriyl group, methanetriyl group, ethanetriyl group, propanetriyl group, butanetriyl group, pentanetriyl group, hexanetriyl group, heptanetriyl group, octanetriyl group, nonanetriyl group, decantriyl group, dodecantriyl group, Examples include a hexadecantriyl group. As alkanetetrayl group, methanetetrayl group, ethanetetrayl group, propanetetrayl group, butanetetrayl group, pentanetetrayl group, hexanetetrayl group, heptanetetrayl group, octanetetrayl group, nonanetetrayl group Decanetetrayl group, dodecanetetrayl group, hexadecanetetrayl group and the like. These aliphatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

  Examples of the alicyclic group include a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkanetriyl group having 3 to 20 carbon atoms, and a cycloalkanetetrayl group having 3 to 20 carbon atoms. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, a cyclodecylene group, a cyclododecylene group, and a cyclohexadecylene group. As the alkanetriyl group, cyclopropanetriyl group, cyclobutanetriyl group, cyclopentanetriyl group, cyclohexanetriyl group, cycloheptanetriyl group, cyclooctanetriyl group, cyclononanetriyl group, cyclodecanetriyl group , Cyclododecanetriyl group, cyclohexadecanetriyl group and the like. As the alkanetetrayl group, cyclopropanetetrayl group, cyclobutanetetrayl group, cyclopentanetetrayl group, cyclohexanetetrayl group, cycloheptanetetrayl group, cyclooctanetetrayl group, cyclononanetetrayl group, cyclodecanetetrayl group Group, cyclododecanetetrayl group, cyclohexadecanetetrayl group and the like. These alicyclic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

  As an aromatic group, each of which contains a hetero atom and may have a heterocyclic structure, an arylene group having 5 to 15 carbon atoms, an arenetriyl group having 5 to 15 carbon atoms, an arenetetra having 5 to 15 carbon atoms Yl group. Examples of the arylene group include a phenylene group and a naphthalenediyl group. Examples of the arenetriyl group (trivalent) include a benzenetriyl group and a naphthalenetriyl group. Examples of the arenetetrayl group (tetravalent) include a benzenetetrayl group and a naphthalenetetrayl group. These aromatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

In the formulas (1-1) and (1-2), s and k are integers of 0 to 10, preferably 0 to 3, more preferably 0 to 1. When s and k exceed 10, the cyclic carbodiimide compound is difficult to synthesize, and the cost may increase significantly. From this viewpoint, the integer is preferably selected in the range of 0 to 3. When s or k is 2 or more, X ¹ or X ² as a repeating unit may be different from other X ¹ or X ² .

X ³ is a divalent to tetravalent C 1-20 aliphatic group, a divalent to tetravalent C 3-20 alicyclic group, each of which may contain a heteroatom and a substituent, A tetravalent aromatic group having 5 to 15 carbon atoms, or a combination thereof.

  Examples of the aliphatic group include an alkylene group having 1 to 20 carbon atoms, an alkanetriyl group having 1 to 20 carbon atoms, and an alkanetetrayl group having 1 to 20 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, a dodecylene group, and a hexadecylene group. As the alkanetriyl group, methanetriyl group, ethanetriyl group, propanetriyl group, butanetriyl group, pentanetriyl group, hexanetriyl group, heptanetriyl group, octanetriyl group, nonanetriyl group, decantriyl group, dodecantriyl group, Examples include a hexadecantriyl group. As alkanetetrayl group, methanetetrayl group, ethanetetrayl group, propanetetrayl group, butanetetrayl group, pentanetetrayl group, hexanetetrayl group, heptanetetrayl group, octanetetrayl group, nonanetetrayl group Decanetetrayl group, dodecanetetrayl group, hexadecanetetrayl group and the like. These aliphatic groups may contain a substituent, such as an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, or an ester group. , Ether group, aldehyde group and the like.

  Examples of the alicyclic group include a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkanetriyl group having 3 to 20 carbon atoms, and a cycloalkanetetrayl group having 3 to 20 carbon atoms. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, a cyclodecylene group, a cyclododecylene group, and a cyclohexadecylene group. As the alkanetriyl group, cyclopropanetriyl group, cyclobutanetriyl group, cyclopentanetriyl group, cyclohexanetriyl group, cycloheptanetriyl group, cyclooctanetriyl group, cyclononanetriyl group, cyclodecanetriyl group , Cyclododecanetriyl group, cyclohexadecanetriyl group and the like. As the alkanetetrayl group, cyclopropanetetrayl group, cyclobutanetetrayl group, cyclopentanetetrayl group, cyclohexanetetrayl group, cycloheptanetetrayl group, cyclooctanetetrayl group, cyclononanetetrayl group, cyclodecanetetrayl group Group, cyclododecanetetrayl group, cyclohexadecanetetrayl group and the like. These alicyclic groups may contain a substituent, such as an alkyl group having 1 to 20 carbon atoms, an arylene group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, and an ester. Group, ether group, aldehyde group and the like.

  As an aromatic group, each of which contains a hetero atom and may have a heterocyclic structure, an arylene group having 5 to 15 carbon atoms, an arenetriyl group having 5 to 15 carbon atoms, an arenetetra having 5 to 15 carbon atoms Yl group. Examples of the arylene group include a phenylene group and a naphthalenediyl group. Examples of the arenetriyl group (trivalent) include a benzenetriyl group and a naphthalenetriyl group. Examples of the arenetetrayl group (tetravalent) include a benzenetetrayl group and a naphthalenetetrayl group. These aromatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ may contain a hetero atom, and when Q is a divalent linking group, Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ are all divalent groups. When Q is a trivalent linking group, one of Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ is a trivalent group. When Q is a tetravalent linking group, one of Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ is a tetravalent group or two are trivalent It is a group.

  Examples of the cyclic carbodiimide compound used in the present invention include compounds represented by the following formulas (2) to (4).

<Cyclic carbodiimide compound (2)>

  In the formula, Qa is a divalent linking group that is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may contain a heteroatom. The aliphatic group, alicyclic group, and aromatic group are the same as those described in Formula (1). However, in the compound of formula (2), the aliphatic group, alicyclic group, and aromatic group are all divalent. Qa is preferably a divalent linking group represented by the following formula (2-1), (2-2) or (2-3).

In the formula, Ar _a ¹ , Ar _a ² , R _a ¹ , R _a ² , X _a ¹ , X _a ² , X _a ³ , s and k are represented by formulas (1-1) to (1-3), respectively. Are the same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k. However, these are all divalent.
Examples of the cyclic carbodiimide compound (2) include the following compounds.

<Cyclic carbodiimide compound (3)>

Wherein, Q _b is an aliphatic group, an alicyclic group, an aromatic group or a trivalent linking group combinations thereof, and may contain a hetero atom. Y is a carrier supporting a cyclic structure. The aliphatic group, alicyclic group, and aromatic group are the same as those described in Formula (1). However, in the compound of formula (3), one of the groups constituting Qb is trivalent. Q _b is preferably a trivalent linking group represented by the following formula (3-1), (3-2) or (3-3).

In the formula, Ar _b ¹ , Ar _b ² , R _b ¹ , R _b ² , X _b ¹ , X _b ² , X _b ³ , s and k are respectively represented by the formulas (1-1) to (1-3). The same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k. However, one of these is a trivalent group.
Y is preferably a single bond, a double bond, an atom, an atomic group or a polymer. Y is a bonding portion, and a plurality of cyclic structures are bonded via Y to form a structure represented by the formula (3). Examples of the cyclic carbodiimide compound (3) include the following compounds.

<Cyclic carbodiimide compound (4)>

In the formula, Q _c is a tetravalent linking group which is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may have a hetero atom. Z ¹ and Z ² are carriers that support a cyclic structure. Z ¹ and Z ² may be bonded to each other to form a cyclic structure.
The aliphatic group, alicyclic group, and aromatic group are the same as those described in Formula (1). However, in the compound of formula (4), Q _c is tetravalent. Accordingly, one of these groups is a tetravalent group or two are trivalent groups. Q _c is preferably a tetravalent linking group represented by the following formula (4-1), (4-2) or (4-3).

Ar _c ¹ , Ar _c ² , R _c ¹ , R _c ² , X _c ¹ , X _c ² , X _c ³ , s and k are each Ar ^{1 in} formulas (1-1) to (1-3). , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k are the same. Provided that Ar _c ¹ , Ar _c ² , R _c ¹ , R _c ² , X _c ¹ , X _c ² and X _c ³ are one of which is a tetravalent group or two of which are trivalent It is a group.
Z ¹ and Z ² are preferably each independently a single bond, a double bond, an atom, an atomic group or a polymer. Z ¹ and Z ² are bonding portions, and a plurality of cyclic structures are bonded via Z ¹ and Z ² to form a structure represented by the formula (4).
Examples of the cyclic carbodiimide compound (4) include the following compounds.

<Method for producing cyclic carbodiimide compound>
The cyclic carbodiimide compound can be produced by a conventionally known method. For example, a method for producing an amine body via an isocyanate body, a method for producing an amine body via an isothiocyanate body, a method for producing an amine body via a triphenylphosphine body, a urea body from an amine body The method of manufacturing via a thiourea body, the method of manufacturing via a thiourea body, the method of manufacturing from a carboxylic acid body via an isocyanate body, the method of manufacturing a lactam body, etc. are mentioned.

  Moreover, the cyclic carbodiimide compound of this invention can be manufactured combining and changing the method described in the following literatures, and an appropriate method can be employ | adopted according to the compound to manufacture.

Tetrahedron Letters, Vol. 34, no. 32, 515-5158, 1993.
Medium- and Large-Membered Rings from Bis (iminophosphoranes): An Efficient Preparation of Cyclic Carbidiimides, Pedro Molina et al.
Journal of Organic Chemistry, Vol. 61, no. 13, 4289-4299, 1996.
New Models for the Study of the Racemization Mechanism of Carbodiimides. Synthesis and Structure (X-ray Crystallography and 1H NMR) of Cyclic Carbodiimides, Pedro Molina et al.
Journal of Organic Chemistry, Vol. 43, No8, 1944-1946, 1978.
Macrocyclic Ureas As Masked Isocynates, Henri Ulrich et al.
Journal of Organic Chemistry, Vol. 48, no. 10, 1694-1700, 1983.
Synthesis and Reactions of Cyclic Carbodiimides,
R. Richter et al.
Journal of Organic Chemistry, Vol. 59, no. 24, 7306-7315, 1994.
A New and Efficient Preparation of Cyclic Carbodiamids from Bis (iminophosphoranea) and the System Boc ₂ O / DMAP, Pedro Molina et al.

（２）得られたニトロ体を還元して下記式（ｄ）で表わされるアミン体を得る工程、

（３）得られたアミン体とトリフェニルホスフィンジブロミドを反応させ下記式（ｅ）で表されるトリフェニルホスフィン体を得る工程、および

（４）得られたトリフェニルホスフィン体を反応系中でイソシアネート化した後、直接脱炭酸させることによって製造したものは、本願発明に用いる環状カルボジイミド化合物として好適に用いることができる。
（上記式中、Ａｒ^１およびＡｒ^２は各々独立に、炭素数１〜６のアルキル基またはフェニル基で置換されていてもよい芳香族基である。Ｅ^１およびＥ^２は各々独立に、ハロゲン原子、トルエンスルホニルオキシ基およびメタンスルホニルオキシ基、ベンゼンスルホニルオキシ基、ｐ−ブロモベンゼンスルホニルオキシ基からなる群から選ばれる基である。Ａｒ^ａは、フェニル基である。Ｘは、下記式（ｉ−１）から（ｉ−３）の結合基である。） Depending on the compound to be produced, an appropriate production method may be employed. For example, (1) nitrophenol represented by the following formula (a-1), nitrophenol represented by the following formula (a-2), and A step of reacting a compound represented by the following formula (b) to obtain a nitro compound represented by the following formula (c);

(2) A step of reducing the obtained nitro body to obtain an amine body represented by the following formula (d);

(3) a step of reacting the obtained amine body with triphenylphosphine dibromide to obtain a triphenylphosphine body represented by the following formula (e); and

(4) After the obtained triphenylphosphine body is isocyanated in the reaction system and then directly decarboxylated, it can be suitably used as the cyclic carbodiimide compound used in the present invention.
(In the above formula, Ar ¹ and Ar ² are each independently an aromatic group optionally substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group. E ¹ and E ² are each independently a halogen atom. A group selected from the group consisting of an atom, a toluenesulfonyloxy group, a methanesulfonyloxy group, a benzenesulfonyloxy group, and a p-bromobenzenesulfonyloxy group, Ar ^a is a phenyl group, X is represented by the following formula (i -1) to (i-3).

（式中、ｎは１〜６の整数である。）

(In the formula, n is an integer of 1 to 6.)

（式中、ｍおよびｎは各々独立に０〜３の整数である。）

(In the formula, m and n are each independently an integer of 0 to 3.)

（式中、Ｒ^１およびＲ^２は各々独立に、炭素数１〜６のアルキル基、フェニル基を表す。）

(In the formula, R ¹ and R ² each independently represents an alkyl group having 1 to 6 carbon atoms or a phenyl group.)

<Polylactic acid>
In the polylactic acid of the present invention, the main chain is mainly composed of lactic acid units represented by the following formula (I), and at least a part of the ends are sealed with a cyclic carbodiimide compound. In the present invention, “mainly” is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and still more preferably 98 to 100 mol%.

  The lactic acid unit represented by the formula (I) includes an L-lactic acid unit and a D-lactic acid unit which are optical isomers. The main chain of polylactic acid may be mainly L-lactic acid units, D-lactic acid units, or a combination thereof.

From the viewpoint of improving heat resistance, polylactic acid is composed of poly-D-lactic acid whose main chain is mainly composed of D-lactic acid units and poly-L-lactic acid whose main chain is mainly composed of L-lactic acid units. Particularly preferred is a stereocomplex polylactic acid.
Here, the proportion of other units constituting the main chain is preferably in the range of 0 to 10 mol%, more preferably 0 to 5 mol%, and still more preferably 0 to 2 mol%.

Stereocomplex crystals usually have a higher melting point than crystals formed solely by poly-L-lactic acid or poly-D-lactic acid, so that even if they are contained in a small amount, the effect of increasing heat resistance can be expected. This is noticeable when the amount of stereocomplex crystals is large. The stereocomplex crystallinity (S) according to the following formula is preferably 95% or more, and more preferably 100%.
S = [ΔHms / (ΔHmh + ΔHms)] × 100
(However, ΔHms is the melting enthalpy of stereocomplex phase crystals, and ΔHmh is the melting enthalpy of homophase polylactic acid crystals.)

In order to stably and highly advance the formation of stereocomplex polylactic acid crystals, a method of blending specific additives is preferably applied.
For example, a technique of adding a metal phosphate represented by the following formula as a stereocomplex crystallization accelerator can be mentioned.

In the formula, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ¹² and R ¹³ each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and M ₁ represents Represents an alkali metal atom, an alkaline earth metal atom, a zinc atom or an aluminum atom, p represents 1 or 2, q represents 0 when M ₁ is an alkali metal atom, an alkaline earth metal atom or a zinc atom; When it is an atom, it represents 1 or 2.

In the formula, each of R ¹⁴ , R ¹⁵ and R ¹⁶ independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and M ₂ represents an alkali metal atom, an alkaline earth metal atom, a zinc atom or an aluminum atom. P represents 1 or 2, q represents 0 when M ₂ is an alkali metal atom, alkaline earth metal atom or zinc atom, and 1 or 2 when M ₂ is an aluminum atom.

M ₁ and M ₂ of the metal phosphate represented by the above two formulas are preferably Na, K, Al, Mg, Ca and Li, and in particular, Li, Al is the most among K, Na, Al and Li. It can be used suitably.
As these metal phosphates, trade names manufactured by ADEKA Corporation, “ADEKA STAB” NA-11, NA-71 and the like are exemplified as suitable agents.

The metal phosphate is used in an amount of 0.001 to 2 wt%, preferably 0.005 to 1 wt%, more preferably 0.01 to 0.5 wt%, more preferably 0.02 to 0.3 wt% with respect to polylactic acid. It is preferable. If the amount is too small, the effect of improving the stereocomplex crystallinity (S) is small. If the amount is too large, the stereocomplex crystal melting point is lowered. Furthermore, in order to reinforce the action of the metal phosphate, a known crystallization nucleating agent can be used in combination. Of these, calcium silicate, talc, kaolinite, and montmorillonite are preferably selected.
The amount of crystallization nucleating agent used is selected in the range of 0.05 to 5 wt%, more preferably 0.06 to 2 wt%, and still more preferably 0.06 to 1 wt% with respect to polylactic acid.

  Polylactic acid may be obtained by any manufacturing method. For example, a polylactic acid production method includes a two-stage lactide method in which L-lactic acid and / or D-lactic acid is used as a raw material to generate lactide, which is a cyclic dimer, and then ring-opening polymerization is performed. It can be suitably obtained by a generally known polymerization method such as a one-step direct polymerization method in which dehydration condensation is directly performed in a solvent using lactic acid and / or D-lactic acid as a raw material.

  Polylactic acid may contain a carboxylic acid group in its production, but the smaller the amount of the carboxylic acid group contained, the better. For these reasons, it is preferable to use, for example, ring-opened polymerization from lactide using an initiator other than water, or a polymer that has been chemically treated after polymerization to reduce carboxylic acid groups.

  The weight average molecular weight of polylactic acid is usually at least 50,000, preferably at least 100,000, preferably 100,000 to 300,000. When the average molecular weight is lower than 50,000, the strength properties of the fiber are lowered, which is not preferable. If it exceeds 300,000, the melt viscosity becomes too high, and melt spinning may be difficult.

  The polylactic acid in the present invention may be a copolymerized polylactic acid obtained by copolymerizing other components having ester forming ability in addition to L-lactic acid and D-lactic acid. The copolymerizable component includes glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, hydroxycarboxylic acids such as 6-hydroxycaproic acid, ethylene glycol, propylene glycol, butanediol, neo Compounds containing a plurality of hydroxyl groups in the molecule such as pentyl glycol, polyethylene glycol, glycerin and pentaerythritol or derivatives thereof, compounds containing a plurality of carboxylic acid groups in the molecule such as adipic acid, sebacic acid and fumaric acid Or derivatives thereof. However, in order to maintain a high melting point and not impair fiber strength, in this case, it is desirable that 70 mol% or more of the polymer is composed of lactic acid units.

  The polylactic acid composition of the present invention contains end-capped polylactic acid having a structure in which a cyclic carbodiimide compound is bonded to the end of polylactic acid. The cyclic carbodiimide compound reacts with the carboxyl group of polylactic acid as follows to form the following structure at the end of polylactic acid.

（式中、Ｗはポリ乳酸の主鎖で、Ｑは、脂肪族基、脂環族基、芳香族基またはこれらの組み合わせである２〜４価の結合基である。）

(Wherein, W is the main chain of polylactic acid, and Q is an aliphatic group, alicyclic group, aromatic group, or a divalent to tetravalent linking group that is a combination thereof.)

  As will be described later, the water-absorbing polylactic acid fiber structure of the present invention can be produced using a polylactic acid composition obtained by mixing polylactic acid and cyclic carbodiimide. The cyclic carbodiimide compound reacts with the end of polylactic acid to seal the end, but when an excess cyclic carbodiimide compound is present, it remains unreacted in the polylactic acid composition. At this time, the water-absorbing polylactic acid fiber structure contains polylactic acid and a cyclic carbodiimide compound whose ends are sealed, but also contains polylactic acid whose ends are not sealed depending on the degree of terminal modification reaction. Sometimes.

In the water-absorbing polylactic acid fiber structure, the content of the cyclic carbodiimide compound remaining in the composition in an unreacted state is 0.001 to 10 parts by weight, preferably 0.01 to 100 parts by weight per 100 parts by weight of polylactic acid. 5 parts by weight, more preferably 0.1 to 1 part by weight.
If there is a cyclic carbodiimide compound remaining in the composition in an unreacted state, the hydrolysis resistance can be further improved.

  The addition of the cyclic carbodiimide compound to the polylactic acid can be performed at any stage from immediately after the completion of the polymerization reaction of the polylactic acid until it is discharged from the spinneret. For example, the cyclic carbodiimide compound is added to the polylactic acid chip as a powder. Examples thereof include a method of adding, and a method of forcibly melt-kneading polylactic acid and a cyclic carbodiimide compound at a stage before melt spinning.

  The method for adding and mixing the cyclic carbodiimide compound to the polylactic acid is not particularly limited, and a method of adding a solution, a melt or a master batch of polylactic acid to be applied by a conventionally known method, or a cyclic carbodiimide compound is dissolved, dispersed or melted. For example, a method can be used in which a solid of polylactic acid is brought into contact with the liquid being infiltrated and the cyclic carbodiimide compound is permeated.

  When taking the method of adding as a solution, a melt or a master batch of polylactic acid to be applied, it can be added using a conventionally known kneading apparatus. In kneading, a kneading method in a solution state or a kneading method in a molten state is preferable from the viewpoint of uniform kneading properties. The kneading apparatus is not particularly limited, and examples thereof include conventionally known vertical reaction vessels, mixing tanks, kneading tanks or uniaxial or multiaxial horizontal kneading apparatuses such as uniaxial or multiaxial ruders and kneaders. The kneading time is not particularly specified and depends on the kneading apparatus and the kneading temperature, but is selected from 0.1 minutes to 2 hours, preferably from 0.2 minutes to 1 hour, more preferably from 1 minute to 30 minutes.

As a solvent, what is inactive with respect to polylactic acid and a cyclic carbodiimide compound can be used. In particular, a solvent is preferred to have affinity for both and at least partially dissolve both, or at least partially dissolve in both.
As such a solvent, for example, a hydrocarbon solvent, a ketone solvent, an ester solvent, an ether solvent, a halogen solvent, an amide solvent and the like can be used.

Examples of the hydrocarbon solvent include hexane, cyclohexane, benzene, toluene, xylene, heptane, decane and the like. Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, and isophorone. Examples of ester solvents include ethyl acetate, methyl acetate, ethyl succinate, methyl carbonate, ethyl benzoate, and diethylene glycol diacetate. Examples of the ether solvent include diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, triethylene glycol diethyl ether, diphenyl ether and the like. Examples of the halogen solvent include dichloromethane, chloroform, tetrachloromethane, dichloroethane, 1,1 ′, 2,2′-tetrachloroethane, chlorobenzene, dichlorobenzene and the like. Examples of amide solvents include formamide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like.
These solvents may be used alone or as a mixed solvent as desired.

  In the present invention, the solvent is applied in the range of 1 to 1,000 parts by weight per 100 parts by weight of the total of polylactic acid and the cyclic carbodiimide compound. If the amount is less than 1 part by weight, there is no significance in applying the solvent. The upper limit of the amount of solvent used is not particularly limited, but is about 1,000 parts by weight from the viewpoints of operability and reaction efficiency.

  When a method in which a polylactic acid solid is brought into contact with a liquid in which the cyclic carbodiimide compound is dissolved, dispersed or melted and the cyclic carbodiimide compound is infiltrated, the solid polylactic acid is brought into contact with the carbodiimide dissolved in the solvent as described above. And a method of bringing solid polylactic acid into contact with an emulsion solution of carbodiimide. As a method of contacting, a method of immersing polylactic acid, a method of applying to polylactic acid, a method of spraying, and the like can be suitably used.

  The sealing reaction with the cyclic carbodiimide compound is possible at a temperature of room temperature (25 ° C.) to about 300 ° C., but is more accelerated in the range of 50 to 250 ° C., more preferably 80 to 200 ° C. from the viewpoint of reaction efficiency. . The reaction of polylactic acid is more likely to proceed in a molten state, but the reaction is preferably performed at a temperature lower than 300 ° C. in order to suppress volatilization and decomposition of the cyclic carbodiimide compound. It is also effective to apply a solvent to lower the melting temperature of polylactic acid and increase the stirring efficiency.

  Although the reaction proceeds sufficiently rapidly without a catalyst, a catalyst that accelerates the reaction can also be used. As a catalyst, the catalyst used with the conventional linear carbodiimide compound is applicable. These can be used alone or in combination of two or more. The addition amount of the catalyst is not particularly limited, but is preferably 0.001 to 1 part by weight, and 0.01 to 0.1 part by weight with respect to 100 parts by weight of the total of polylactic acid and the cyclic carbodiimide compound. More preferred is 0.02 to 0.1 parts by weight.

  The application amount of the cyclic carbodiimide compound is selected such that the carbodiimide group contained in the cyclic carbodiimide compound is 0.5 to 100 equivalents per equivalent of acidic group. If the amount is less than 0.5 equivalent, there may be no significance in applying carbodiimide. On the other hand, if it exceeds 100 equivalents, the characteristics of the substrate may be altered. From this viewpoint, on the above criteria, a range of preferably 0.6 to 100 equivalents, more preferably 0.65 to 70 equivalents, further preferably 0.7 to 50 equivalents, and particularly preferably 0.7 to 30 equivalents is selected. Is done.

<Water-absorbing polylactic acid fiber structure>
In the water-absorbing polylactic acid fiber structure of the present invention, the polylactic acid fiber structure is preferably a woven fabric or a knitted fabric.
In the water-absorbing polylactic acid fiber structure, the water absorption rate measured by the JIS L-1018A method (drop method) is preferably 5 seconds or less.

  In the present invention, the polylactic acid fiber is a fiber made of the above-mentioned polylactic acid composition, and the fiber strength is preferably 2.3 cN / dtex or more in terms of tensile strength. 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. At that time, the number of ejection 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 is preferably in the range of 300 to 5000 m / min from the viewpoint of oriented crystallinity. 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.

  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. The heat treatment is performed at 110 to 210 ° C. (preferably 120 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, a fiber having excellent heat resistance and iron resistance and high fiber strength can be obtained.

  The polylactic acid fiber structure used in the production method of the present invention is a polylactic acid fiber structure containing the polylactic acid fiber (in the present application, it may be simply referred to as a fiber structure). 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 yarn may be subjected to twisting, air processing, false twist crimping, or the like. 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. Moreover, the single fiber cross-sectional shape of the said polylactic acid fiber and / or the said polyester fiber is not specifically limited, As shown typically in a normal round cross section, a round hollow cross section, a triangular cross section, a square cross section, a flat cross section, FIG. Any flat cross-section with a neck may be used, but a modified cross-section yarn having a surface area larger than that of a round cross-section is preferred because of its excellent water absorption. In addition, it is preferable to have voids and / or cracks on the surface of the single fiber of the polylactic acid fiber and / or the polyester fiber to improve water absorption.

  The structure of the fiber structure is not particularly limited, but is preferably a woven or knitted fabric woven or knitted by a normal loom or knitting machine. Of course, a non-woven fabric or a fiber structure composed of matrix fibers and heat-bondable fibers may be used. For example, 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 a flat knitted fabric, rubber knitted fabric, double-sided knitted fabric, pearl knitted fabric, tucked knitted fabric, float knitted fabric, one-sided knitted fabric, lace knitted fabric, and bristle knitted fabric. Examples include a single denby knitting, a single atlas knitting, a double cord knitting, a half tricot knitting, a back hair knitting, and a jacquard knitting. The number of layers may be a single layer or a multilayer of two or more layers. Furthermore, it may be a raised fabric composed of a raised portion made of a cut pile and / or a loop pile and a ground tissue portion.

  In the production method of the present invention, the fiber structure is subjected to water absorption processing. At that time, as conditions for the water absorption processing, hydrophilizing agents such as PEG diacrylate and its derivatives and polyethylene terephthalate-polyethylene glycol copolymer were applied to the fiber structure in the same bath as the padding method or dyeing, and then the temperature was changed. It is good to dry at 60-150 degreeC and time 0.2-5 minutes. At that time, the adhesion amount of the hydrophilizing agent is preferably 0.1 to 10% by weight with respect to the weight of the fiber structure before water absorption processing.

  In addition, in the process before and / or after the water absorption processing, ordinary dyeing processing, alkali weight reduction processing, water repellency processing, brushed processing, UV shielding or antibacterial agent, deodorant, insect repellent, phosphorescent agent, retroreflective agent, Various processings that impart functions such as a negative ion generator may be additionally applied.

  In particular, as described in Japanese Patent Application Laid-Open No. 2007-162150, a water repellent agent is applied only to one surface of the polylactic acid fiber structure by performing water repellent processing only on one surface of the fiber structure following the water absorption processing. Is preferably attached. In particular, as schematically shown in FIG. 2, it is preferable that the water repellent agent is partially attached to one side of the fiber structure in a pattern having a polygonal continuous portion at the corners. In this way, when the adhesion pattern of the water repellent is continuous in the warp and weft directions, the non-adhered part becomes a flying island shape, so that the water absorbed by the non-adhered part can be smoothly diffused without diffusion. Migrate to In addition, there is no risk of damaging the soft texture. On the other hand, as schematically shown in FIG. 3, when the water repellent is attached in a vertical and horizontal lattice pattern, the moisture absorbed in the non-adhered portion smoothly moves to the other surface without diffusing. Soft texture may be damaged.

  In this case, the polygon is preferably a quadrangle or a triangle. As the size of the polygon, the length of one side of the polygon is preferably in the range of 0.5 to 2.0 mm (more preferably 0.7 to 1.5 mm). Even if the length is smaller than 0.5 mm or larger than 2.0 mm, sufficient water absorption may not be obtained. In addition, the size of the lattice pattern is preferably in the range of 0.5 to 3.0 mm of the attached portion and 1.0 to 5.0 mm of the non-attached portion.

In the water repellent adhesion pattern, the area ratio of the water repellent adhesion area is preferably in the range of 30 to 85% (more preferably 40 to 70%). If the adhesion area ratio is less than 30%, water may spread in the surface direction during water absorption, and the wettability may not be sufficiently reduced. On the other hand, when the area ratio of the adhering part is larger than 85%, not only the water absorption is lowered, but also the soft texture may be impaired.
The adhesion area ratio is represented by the following formula.
Adhering part area ratio (%) = (adhering part area) / ((adhering part area) + (non-adhering part area)) × 100

  The water-absorbing polylactic acid fiber structure thus obtained not only has excellent water absorption, but the polylactic acid fiber contained in the fiber structure has excellent fiber strength. Here, since the polylactic acid fiber has a glass transition point lower than that of ordinary polyethylene terephthalate, it is excellent in exhaustion of the hydrophilic agent and exhibits water absorption superior to that of polyethylene terephthalate fiber. As such water absorption, it is preferable that the water absorption rate measured by JIS L-1018A method (drop method) is 5 seconds or less. The fiber strength is preferably 2.3 cN / dtex or more (more preferably 3 to 10 cN / dtex). 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).

  Next, the textile product of the present invention is any textile product selected from the group consisting of sports apparel, inner apparel, men's apparel, and women's apparel using the water-absorbing polylactic acid fiber structure. Since such a fiber product contains the water-absorbing polylactic acid fiber structure, it exhibits excellent water absorption, and at the same time, the fiber strength of the poly milk fiber contained in the fiber product is high.

  In addition, the water-absorbing polylactic acid fiber structure is a vehicle interior material such as a car seat skin material, a floor material, a ceiling material, a clothing material such as a cup and a pad, a curtain, a carpet, a mat, Furniture and other interior goods, belts, nets, ropes, heavy cloth, bags, felts, filters, and other industrial materials, accessories, form straps, glasses, tableware, mouse pads, stuffed animals, toys, hats, gloves, white It is also suitably used as small items such as board cleaners and notebook covers.

<Stabilizer>
The water-absorbing polylactic acid fiber structure of the present invention can contain a stabilizer. As a stabilizer, what is used for the stabilizer of a normal thermoplastic resin can be used. For example, an antioxidant, a light stabilizer, etc. can be mentioned. By blending these agents, a molded product having excellent mechanical properties, moldability, heat resistance and durability can be obtained.

  Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, phosphite compounds, thioether compounds, and the like.

  Examples of hindered phenol compounds include n-octadecyl-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) -propionate, n-octadecyl-3- (3′-methyl-5 ′). -Tert-butyl-4'-hydroxyphenyl) -propionate, n-tetradecyl-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) -propionate, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate], 1,4-butanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -Propionate], 2,2'-methylene-bis (4-methyl-tert-butylphenol), triethylene glycol-bis 3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate], tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro ( 5,5) Undecane and the like can be mentioned.

  As a hindered amine compound, N, N′-bis-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionylhexamethylenediamine, N, N′-tetramethylene-bis [3- (3′-Methyl-5′-tert-butyl-4′-hydroxyphenyl) propionyl] diamine, N, N′-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionyl ] Hydrazine, N-salicyloyl-N'-salicylidenehydrazine, 3- (N-salicyloyl) amino-1,2,4-triazole, N, N'-bis [2- {3- (3,5-di -Tert-butyl-4-hydroxyphenyl) propionyloxy} ethyl] oxyamide and the like. Preferably, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate] and tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl) -4-hydroxyphenyl) propionate] methane and the like.

  As the phosphite compound, those in which at least one P—O bond is bonded to an aromatic group are preferable. Specifically, tris (2,6-di-tert-butylphenyl) phosphite, tetrakis ( 2,6-di-tert-butylphenyl) 4,4′-biphenylene phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol di-phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2-methyl-4-ditridecyl phosphite-5-tert-butylphenyl) butane, tris (mixed mono and di-no Butylphenyl) phosphite, tris (nonylphenyl) phosphite, 4,4'-isopropylidene-bis (phenyl - dialkyl phosphite), and the like.

  Among them, tris (2,6-di-tert-butylphenyl) phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (2,6-di-tert-butyl) -4-Methylphenyl) pentaerythritol-diphosphite, tetrakis (2,6-di-tert-butylphenyl) 4,4′-biphenylene phosphite and the like can be preferably used.

  Specific examples of thioether compounds include dilauryl thiodipropionate, ditridecyl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, pentaerythritol-tetrakis (3-lauryl thiopropionate), Pentaerythritol-tetrakis (3-dodecylthiopropionate), pentaerythritol-tetrakis (3-octadecylthiopropionate), pentaerythritol tetrakis (3-myristylthiopropionate), pentaerythritol-tetrakis (3-stearylthio) Propionate) and the like.

  Specific examples of the light stabilizer include benzophenone compounds, benzotriazole compounds, aromatic benzoate compounds, oxalic acid anilide compounds, cyanoacrylate compounds, hindered amine compounds, and the like.

  Examples of the benzophenone compounds include benzophenone, 2,4-dihydroxybenzophenone, 2,2′-dihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2 ′. -Dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 5-chloro-2-hydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxy -2 - carboxy benzophenone, 2-hydroxy-4- (2-hydroxy-3-methyl - acryloxy-isopropoxyphenyl) benzophenone.

  Examples of the benzotriazole compound include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3,5- Di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (3 ′, 5′-di-tert-butyl-4′-methyl-2′-hydroxyphenyl) benzotriazole, 2- (3,5- Di-tert-amyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (5-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- [2′-hydroxy-3 ′, 5′-bis (Α, α-Dimethylbenzyl) phenyl] benzotriazole, 2- [2′-hydroxy-3 ′, 5′-bis (α, α Dimethylbenzyl) phenyl] -2H- benzotriazole, 2- (4'-octoxy-2'-hydroxyphenyl) benzotriazole.

  Examples of the aromatic benzoate compounds include alkylphenyl salicylates such as p-tert-butylphenyl salicylate and p-octylphenyl salicylate.

  Examples of oxalic acid anilide compounds include 2-ethoxy-2′-ethyloxalic acid bisanilide, 2-ethoxy-5-tert-butyl-2′-ethyloxalic acid bisanilide, and 2-ethoxy-3′-. Examples include dodecyl oxalic acid bisanilide.

  Examples of the cyanoacrylate compound include ethyl-2-cyano-3,3'-diphenyl acrylate, 2-ethylhexyl-cyano-3,3'-diphenyl acrylate, and the like.

  Examples of hindered amine compounds include 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6, 6-tetramethylpiperidine, 4- (phenylacetoxy) -2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2, 6,6-tetramethylpiperidine, 4-octadecyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2 , 6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4- (ethylcarba Yloxy) -2,2,6,6-tetramethylpiperidine, 4- (cyclohexylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6,6 -Tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) carbonate, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2,6 , 6-tetramethyl-4-piperidyl) malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethylpi-4-peridyl) adipate, bis (2,2,6,6-tetramethylpi-4-peridyl) terephthalate, 1,2-bis (2,2,6,6-tetramethylpi-4-peridylo) Cis) -ethane, α, α′-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -p-xylene, bis (2,2,6,6-tetramethyl-4-piperidyl) -Tolylene-2,4-dicarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) -hexamethylene-1,6-dicarbamate, tris (2,2,6,6-tetramethyl -4-piperidyl) -benzene-1,3,5-tricarboxylate, tris (2,2,6,6-tetramethyl-4-piperidyl) -benzene-1,3,4-tricarboxylate, 1- “2- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} -2,2,6,6-tetramethylpiperidine, 1,2,3,4-butanetetracarboxylic acid And 1,2,2, , 6-Pentamethyl-4-piperidinol and β, β, β ′, β′-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] dimethanol And the like. In the present invention, the stabilizer component may be used alone or in combination of two or more. As the stabilizer component, a hindered phenol compound and / or a benzotriazole compound are preferable. The content of the stabilizer is preferably 0.01 to 3 parts by weight, more preferably 0.03 to 2 parts by weight, per 100 parts by weight of polylactic acid.

<Antiwear agent>
In the present invention, a fatty acid bisamide and / or an alkyl-substituted monoamide can be contained in order to improve the abrasion resistance of the water-absorbing polylactic acid fiber structure.
An aliphatic bisamide refers to a compound having two amide bonds in one molecule such as a saturated fatty acid bisamide, an unsaturated fatty acid bisamide, an aromatic fatty ginseng bisamide, such as methylene biscaprylic amide, methylene biscapric amide, Methylene bis lauric acid amide, methylene bis myristic acid amide, methylene bis palmitic acid amide, methylene bis stearic acid amide, methylene bis isostearic acid amide, methylene bis behenic acid amide, methylene bis oleic acid amide, methylene bis erucic acid amide, Ethylene biscaprylic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bismyristic acid amide, ethylene bispalmitic acid amide, ethylene bisstearic acid amide, ethylene bisisostearate Acid amide, ethylene bis behenic acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, butylene bis stearic acid amide, butylene bis behenic acid amide, butylene bis oleic acid amide, butylene bis erucic acid amide, Hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bis oleic acid amide, hexamethylene bis erucic acid amide, m-xylylene bis stearic acid amide, m-xylylene bis-12-hydroxy stearic acid amide, p-xylylene bis-stearic acid amide, p-phenylene bis-stearic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, N, N′-dioleyl adipic acid amide, N, N'-di Stearyl terephthalic acid amide, methylene bis-hydroxystearic acid amide, ethylenebis-hydroxystearic acid amide, butylene-bis-hydroxystearic acid amide, hexamethylene bis hydroxystearic acid amide.

  In addition, the alkyl-substituted monoamide referred to in the present invention refers to a compound having a structure in which amide hydrogen such as saturated fatty acid monoamide or unsaturated fatty acid monoamide is substituted with an alkyl group, such as N-lauryl lauric acid amide, N-par. Mitylpalmitic acid amide, N-stearyl stearic acid amide, N-hebenyl hebenic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid Examples include acid amides. In the alkyl group, a substituent such as a hydroxyl group may be introduced into the structure. For example, methylose stearamide, N-stearyl-12-hydroxystearic amide, N-oleyl-12-hydroxystearin Acid amides and the like are also included in the alkyl-substituted fatty acid amides of the present invention.

  These compounds are less reactive with amides than ordinary fatty acid monoamides, and hardly react with polylactic acid during melt molding. In addition, since many of them have a high molecular weight, they generally have good heat resistance and are difficult to sublimate. In particular, fatty acid bisamides can be used as a more preferred antiwear agent because they are less reactive with polylactic acid due to their lower reactivity with amides, and because they have a high molecular weight, they have good heat resistance and are not easily sublimated. Examples of such antiwear agents include ethylene bis stearamide, ethylene bisisostearic acid amide, ethylene bis behenic acid amide, butylene bis stearic acid amide, butylene bis behenic acid amide, hexamethylene bis behenine. Acid amide and m-xylylene bis-stearic acid amide are preferable.

  In the present invention, the content of fatty acid bisamide and / or alkyl-substituted monoamide (hereinafter abbreviated as “fatty acid amide”) with respect to the entire short fibers is preferably 0.1 to 1.5 wt%. More preferably, it is 0.5 to 1.0 wt%. When the content of the fatty acid amide is 0.1 wt% or less, a sufficient effect for the purpose does not appear, and when the content is 1.5 wt% or more, the slipping property of the short fiber is improved, but the effect is too great, so It leads to deterioration in operability due to intertwining and deterioration in quality such as deterioration in crimp uniformity. The fatty acid amide may be a single component, or a plurality of components may be mixed.

<Crystallization accelerator>
The polylactic acid composition of the present invention can contain an organic or inorganic crystallization accelerator. By containing the crystallization accelerator, a molded product having excellent mechanical properties, heat resistance, and moldability can be obtained.
That is, by applying the crystallization accelerator, moldability and crystallinity are improved, and a molded product that is sufficiently crystallized even in normal injection molding and excellent in heat resistance and moist heat resistance can be obtained. In addition, the manufacturing time for manufacturing the molded product can be greatly shortened, and the economic effect is great.

As the crystallization accelerator used in the present invention, those generally used as crystallization nucleating agents for crystalline resins can be used, and both inorganic crystallization nucleating agents and organic crystallization nucleating agents are used. be able to.
As inorganic crystallization nucleating agents, talc, kaolin, silica, synthetic mica, clay, zeolite, graphite, carbon black, zinc oxide, magnesium oxide, titanium oxide, calcium carbonate, calcium sulfate, barium sulfate, calcium sulfide, boron nitride Montmorillonite, neodymium oxide, aluminum oxide, phenylphosphonate metal salt and the like. These inorganic crystallization nucleating agents are treated with various dispersing aids in order to enhance the dispersibility in the composition and the effect thereof, and are in a highly dispersed state with a primary particle size of about 0.01 to 0.5 μm. Are preferred.

  Organic crystallization nucleating agents include calcium benzoate, sodium benzoate, lithium benzoate, potassium benzoate, magnesium benzoate, barium benzoate, calcium oxalate, disodium terephthalate, dilithium terephthalate, dipotassium terephthalate, Sodium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, barium myristate, sodium octacolate, calcium octacolate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate , Barium stearate, sodium montanate, calcium montanate, sodium toluate, sodium salicylate, potassium salicylate, salicy Organic carboxylic acid metal salts such as zinc acid, aluminum dibenzoate, β-naphthoic acid sodium, β-naphthoic acid potassium, sodium cyclohexanecarboxylic acid and the like, and organic sulfonic acid metal salts such as sodium p-toluenesulfonate and sodium sulfoisophthalate. Can be mentioned.

  Also, organic carboxylic acid amides such as stearic acid amide, ethylenebislauric acid amide, palmitic acid amide, hydroxystearic acid amide, erucic acid amide, trimesic acid tris (tert-butylamide), low density polyethylene, high density polyethylene, polyiso Propylene, polybutene, poly-4-methylpentene, poly-3-methylbutene-1, polyvinylcycloalkane, polyvinyltrialkylsilane, high melting point polylactic acid, sodium salt of ethylene-acrylic acid copolymer, sodium of styrene-maleic anhydride copolymer Examples thereof include salts (so-called ionomers), benzylidene sorbitol and derivatives thereof such as dibenzylidene sorbitol.

Among these, at least one selected from talc and organic carboxylic acid metal salts is preferably used. Only one type of crystallization accelerator may be used in the present invention, or two or more types may be used in combination.
The content of the crystallization accelerator is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 20 parts by weight per 100 parts by weight of polylactic acid.

<Antistatic agent>
The water-absorbing polylactic acid fiber structure of the present invention can contain an antistatic agent. Examples of the antistatic agent include quaternary ammonium salt compounds such as (β-lauramidopropionyl) trimethylammonium sulfate and sodium dodecylbenzenesulfonate, sulfonate compounds, and alkyl phosphate compounds.
In the present invention, the antistatic agent may be used alone or in combination of two or more. The content of the antistatic agent is preferably 0.05 to 5 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of polylactic acid.

<Plasticizer>
The water-absorbing polylactic acid fiber structure of the present invention can contain a plasticizer. As the plasticizer, generally known plasticizers can be used. Examples include polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers, phosphate ester plasticizers, polyalkylene glycol plasticizers, and epoxy plasticizers.

  As a polyester plasticizer, acid components such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, Examples thereof include polyesters composed of diol components such as 1,6-hexanediol and diethylene glycol, and polyesters composed of hydroxycarboxylic acids such as polycaprolactone. These polyesters may be end-capped with a monofunctional carboxylic acid or a monofunctional alcohol.

  Examples of the glycerol plasticizer include glycerol monostearate, glycerol distearate, glycerol monoacetomonolaurate, glycerol monoacetomonostearate, glycerol diacetomonooleate, and glycerol monoacetomonomontanate.

  Polyvalent carboxylic acid plasticizers include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, trimellitic acid tributyl, trimellitic acid trioctyl, Trimellitic acid esters such as trihexyl meritate, isodecyl adipate, adipic acid esters such as adipate-n-decyl-n-octyl, citrate esters such as tributyl acetylcitrate, and bis (2-ethylhexyl) azelate Examples include sebacic acid esters such as azelaic acid ester, dibutyl sebacate, and bis (2-ethylhexyl) sebacate.

  Examples of the phosphate ester plasticizer include tributyl phosphate, tris phosphate (2-ethylhexyl), trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, diphenyl-2-ethylhexyl phosphate, and the like.

  Polyalkylene glycol plasticizers such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (ethylene oxide-propylene oxide) block and / or random copolymers, ethylene oxide addition polymers of bisphenols, tetrahydrofuran addition polymers of bisphenols, etc. And end-capping compounds such as a terminal epoxy-modified compound, a terminal ester-modified compound, and a terminal ether-modified compound.

  Examples of the epoxy plasticizer include an epoxy triglyceride composed of alkyl epoxy stearate and soybean oil, and an epoxy resin using bisphenol A and epichlorohydrin as raw materials.

  Specific examples of other plasticizers include benzoic acid esters of aliphatic polyols such as neopentyl glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol-bis (2-ethylbutyrate), and fatty acids such as stearamide. Examples thereof include fatty acid esters such as amide and butyl oleate, oxyacid esters such as methyl acetylricinoleate and butyl acetylricinoleate, pentaerythritol, various sorbitols, polyacrylic acid esters, silicone oils, and paraffins.

  As the plasticizer, at least one selected from polyester-type plasticizers and polyalkylene-type plasticizers can be preferably used, and only one type may be used, or two or more types may be used in combination.

  The content of the plasticizer is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 20 parts by weight, and still more preferably 0.1 to 10 parts by weight per 100 parts by weight of polylactic acid. In the present invention, each of the crystallization nucleating agent and the plasticizer may be used alone, or more preferably used in combination.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these specific examples. The method for measuring the characteristics used in this example is as follows.

(1) Hydrolysis resistance:
Hydrolysis resistance is determined to be good when the carboxyl group terminal amount of the composition is 0 equivalent / ton, and is determined to be acceptable when it is 10 equivalent / ton or less, and exceeds 10 equivalent / ton. No. The terminal amount of the carboxyl group was determined by dissolving a weighed sample in o-cresol adjusted to a water content of 5%, adding an appropriate amount of dichloromethane to this solution, and titrating with 0.02 N potassium hydroxide methanol solution. .

(2) Melting point, crystallization point:
A 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, and the peak top temperatures of the crystal melting endothermic peak and the crystallization exothermic peak were defined as the melting point and the crystallization point, respectively. .

(3) Strength:
Using “Tensilon” (trade name) manufactured by Orientic Corporation, ten target single yarns (filaments) are randomly extracted from the fiber structure to be measured, the yarn sample length is 50 mm (length between chucks), and the elongation speed is 500 mm. The strain-stress curve was measured under the conditions of an atmospheric temperature of 20 ° C. and a relative humidity of 65% under the conditions of / min, and after obtaining the strength (cN / piece) from the stress and elongation at the breaking point, the strength was divided by the fineness. The fiber strength (cN / dtex).

(4) Wetness:
First, 0.3 cc of water is placed on an acrylic plate, and a woven or knitted fabric cut into a 10 cm square is placed on the acrylic plate, and water is sufficiently absorbed into the woven or knitted fabric for 30 seconds while applying a load of 2.9 mN / cm 2 (0.3 gf / cm 2). Then, the woven or knitted fabric that had absorbed water was placed on the upper arm of 10 panelists, 5 each for men and women, and the sensory evaluation of the wet feeling was performed. The evaluation was made on the basis of a wet feeling, and was evaluated in four levels, that is, a minimum (best), a small, a medium, and a large. In addition, the amount of water of 0.3 ml placed on the acrylic plate was a sufficient amount to wet and spread over the entire 10 cm square fabric.

(5) Dryability:
First, the initial mass (A) of a woven or knitted fabric cut into a 10 cm square was measured, and the woven or knitted fabric was placed on a constant temperature plate placed at a constant temperature of 32 ° C., and 0.2 cc / min from the back of the woven or knitted fabric with a metering pump. Water at a speed of 10 minutes to give excess moisture to the fabric. After 10 minutes, the water supply is stopped, the amount of the knitted and knitted material (B) at this time is measured, and left in a constant temperature room at 32 ° C. for a while. After standing for 10 minutes, the amount of woven / knitted material (C) was measured again, and the drying property was evaluated by the following formula.
Dryability (%) = ((BC) / (BA)) × 100
In addition, the drying property represented by this is a value from 0 to 100, and the larger the numerical value, the higher the drying property. The dryness evaluation method shown here is an experimental evaluation method that assumes that sweating begins at the start of exercise and that sweating stops after the end of exercise, and the amount of sweat absorbed by the woven or knitted fabric is about 200 g / m ² · hr. It is assumed that the exercise was performed for 1 hour and then rested for 10 minutes. The exercise with the amount of sweat absorbed by the fabric of about 200 g / m2 · hr can be thought of as a serious exercise of basketball, tennis, running, etc. for about an hour. Usually, a commercially available cotton T-shirt is worn on the upper garment. If so, the cotton T-shirt will be wet with sweat.

(6) Water absorption:
It measured according to the test method regarding the water absorption speed of JIS L-1018A method (drop method). The time for one drop of water dropped on the horizontal sample surface to be absorbed is shown.

(7) Washing durability:
Washing was carried out with a normal home washing machine, and the number of washings when the initial performance was halved was evaluated.

(8) Texture of woven or knitted fabric:
Sensory evaluation was performed on a 30 cm square woven or knitted fabric in a state where a total of 10 panelists were blindfolded by 5 men and women. From the viewpoint of softness, it was evaluated in four levels: soft (best), slightly soft, slightly hard, and hard.

(9) Thickness:
For woven fabrics, the thickness is measured by the thickness measurement method of JIS L-1096: 1998, 6.5, and for the knitted fabric, the thickness is measured by the thickness measurement method of JIS L-1018: 1998, 6.5. To do.

(10) Contact angle:
The contact angle between the binder resin and ordinary polyethylene terephthalate fiber was measured with a contact angle measuring device (manufactured by Elma Sales Co., Ltd.).

(11) Quality of work environment:
Judgment was made based on whether the working environment was deteriorated by the isocyanate odor during the production of the resin composition. When it did not deteriorate, it was evaluated as good.

(12) Presence or absence of generation of isocyanate odor When the obtained water-absorbing polylactic acid fiber structure was melted at 300 ° C. for 5 minutes, it was determined by sensory evaluation whether or not the measurer felt an isocyanate odor. When the isocyanate odor was not felt, it was judged to be acceptable.

In this example, the following agents were produced and used as the cyclic carbodiimide compound.
[Production Example 1] Synthesis of cyclic carbodiimide compound CC1 (MW = 252):
Reaction in which 200 ml of o-nitrophenol (0.11 mol), 1,2-dibromoethane (0.05 mol), potassium carbonate (0.33 mol), and N, N-dimethylformamide (DMF) were installed with a stirrer and a heating device The apparatus was charged in an N ₂ atmosphere and reacted at 130 ° C. for 12 hours. After that, DMF was removed under reduced pressure, and the resulting solid was dissolved in 200 ml of dichloromethane and separated three times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and dichloromethane was removed under reduced pressure to obtain an intermediate product A (nitro form).

  Next, intermediate product A (0.1 mol), 5% palladium carbon (Pd / C) (1 g), and 200 ml of ethanol / dichloromethane (70/30) were charged into a reactor equipped with a stirrer, and 5 hydrogen substitution was performed. The reaction was performed in a state where hydrogen was constantly supplied at 25 ° C., and the reaction was terminated when there was no decrease in hydrogen. When Pd / C was recovered and the mixed solvent was removed, an intermediate product B (amine body) was obtained.

Next, triphenylphosphine dibromide (0.11 mol) and 150 ml of 1,2-dichloroethane were charged and stirred in a reactor equipped with a stirring device, a heating device, and a dropping funnel in an N ₂ atmosphere. A solution prepared by dissolving intermediate product B (0.05 mol) and triethylamine (0.25 mol) in 50 ml of 1,2-dichloroethane was gradually added dropwise thereto at 25 ° C. After completion of dropping, the reaction was carried out at 70 ° C. for 5 hours. Thereafter, the reaction solution was filtered, and the filtrate was separated 5 times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and 1,2-dichloroethane was removed under reduced pressure to obtain an intermediate product C (triphenylphosphine compound).

Next, in a reactor equipped with a stirrer and a dropping funnel, di-tertbutyl dicarbonate (0.11 mol), N, N-dimethyl-4-aminopyridine (0.055 mol), dichloromethane 150 ml under N ₂ atmosphere. Were charged and stirred. Thereto, 100 ml of dichloromethane in which the intermediate product C (0.05 mol) was dissolved was slowly added dropwise at 25 ° C. After dropping, the reaction was allowed to proceed for 12 hours.
Then, CC1 shown by the following structural formula was obtained by refine | purifying the solid substance obtained by removing dichloromethane. The structure of CC1 was confirmed by NMR and IR.

[Production Example 2] Synthesis of cyclic carbodiimide compound CC2 (MW = 516):
o- nitrophenol (0.11 mol) and pentaerythrityl tetra bromide (0.025 mol), potassium carbonate (0.33mol), _N, N ₂ N- dimethylformamide 200ml in reactor installed with a stirrer and a heating device After charging in an atmosphere and reacting at 130 ° C. for 12 hours, DMF was removed under reduced pressure, and the resulting solid was dissolved in 200 ml of dichloromethane and separated three times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and dichloromethane was removed under reduced pressure to obtain an intermediate product D (nitro form).

  Next, intermediate product D (0.1 mol), 5% palladium carbon (Pd / C) (2 g), and 400 ml of ethanol / dichloromethane (70/30) were charged into a reactor equipped with a stirrer, and 5 hydrogen substitution was performed. The reaction was performed in a state where hydrogen was constantly supplied at 25 ° C., and the reaction was terminated when there was no decrease in hydrogen. Pd / C was recovered, and the mixed solvent was removed to obtain an intermediate product E (amine body).

Next, triphenylphosphine dibromide (0.11 mol) and 150 ml of 1,2-dichloroethane were charged and stirred in a reactor equipped with a stirrer, a heating device, and a dropping funnel in an N ₂ atmosphere. A solution prepared by dissolving the intermediate product E (0.025 mol) and triethylamine (0.25 mol) in 50 ml of 1,2-dichloroethane was gradually added dropwise thereto at 25 ° C. After completion of dropping, the reaction was carried out at 70 ° C. for 5 hours.
Thereafter, the reaction solution was filtered, and the filtrate was separated 5 times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and 1,2-dichloroethane was removed under reduced pressure to obtain an intermediate product F (triphenylphosphine compound).

Next, in a reactor equipped with a stirrer and a dropping funnel, di-tert-butyl dicarbonate (0.11 mol), N, N-dimethyl-4-aminopyridine (0.055 mol), dichloromethane under N ₂ atmosphere. 150 ml is charged and stirred. Thereto, 100 ml of dichloromethane in which the intermediate product F (0.025 mol) was dissolved was slowly added dropwise at 25 ° C. After dropping, the reaction was allowed to proceed for 12 hours.
Then, CC2 shown by the following structural formula was obtained by refine | purifying the solid substance obtained by removing dichloromethane. The structure of CC2 was confirmed by NMR and IR.

[Production Example 3] (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 4] (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 to obtain poly-D-lactic acid.
The obtained poly-D-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 5] (Production of stereocomplex polylactic acid resin)
50 parts by weight of each of the poly L-lactic acid obtained in Production Example 3 and the poly D-lactic acid of Production Example 4 and a phosphate ester metal salt (2,2-methylenebis (4,6-di-tert-butylphenol) phosphate) Sodium salt, average particle diameter of 5 μm, ADEKA ADEKA STAB NA-11) 0.1 parts by weight is melt-kneaded at 230 ° C., strands are taken in a water tank, and chip-cuttered to obtain a stereocomplex polylactic acid chip. It was. The obtained stereocomplex polylactic acid resin had an Mw of 135,000, a melting point (Tm) of 217 ° C., and a stereocomplex crystallinity of 100%.

[Example 1] Production of water-absorbing polylactic acid fiber structure 1:
The poly L-lactic acid chip and the cyclic carbodiimide compound (CC1) obtained by the operation of Production Example 3 were each dried and then mixed at a weight ratio of 99: 1, and 220 ° C. using an extruder-type spinning machine. After being melted at a temperature of 50 ° C., discharged from a die having 30 discharge holes, cooled by a spinning cylinder, an oil agent was added and the undrawn yarn was wound up at a speed of 500 m / min. The wound undrawn yarn was drawn 4.9 times with a drawing machine at 80 ° C. by preheating and wound up the drawn yarn, then heat treated at 120 ° C., and further subjected to false twist crimping. The process passability in the spinning process and the drawing process was good, and the obtained false twist crimped yarn was a multifilament having a fineness of 190 dTex / 48 fil (single fiber cross-sectional shape is a round cross section).
Next, using the false twisted crimped yarn as the warp and the false twisted crimped yarn (1: 1 use) as the weft, weft double woven fabric (raw warp density 100 / 2.54 cm, raw weft density After weaving 160 pieces / 2.54 cm), after refining at 80 ° C. and then subjecting to normal dyeing at 110 ° C. for 30 minutes, a hydrophilic agent made of a polyethylene terephthalate-polyethylene glycol copolymer (manufactured by Takamatsu Yushi Co., Ltd.) SR-1000) was subjected to water absorption processing in the same bath (5% owf), followed by drying (temperature 110 ° C., 3 minutes) and setting (temperature 150 ° C., 1 minute).

Next, a checkered grid pattern (square size 1 mm × 1 mm, coating portion area ratio 50%) is applied to one side of the woven fabric so that a treatment liquid having the following formulation is applied in an amount of about 15 g / m ² . ), And then dried at 110 ° C. and then subjected to a dry heat treatment at 130 ° C. for 45 seconds to obtain a woven fabric.
[Composition of treatment liquid]
-Water: 91.6% by weight
・ Fluorine-based water repellent: 8% by weight
("Asahi Guard AG710" manufactured by Asahi Glass Co., Ltd.)
・ Melamine binder resin: 0.3% by weight
(Sumitomo Chemical "Sumitex Resin M-3" contact angle 67.5 degrees)
Catalyst: 0.1% by weight
(Sumitex Accelerator ACX)
In the obtained woven fabric, the warp density is 140 / 2.54 cm, the weft density of the raw machine is 180 / 2.54 cm, the thickness is 0.5 mm, the wet feeling is medium to low, the water absorption is 1.4 seconds, the drying property is 72%, and the washing is performed. The durability was 30 times, the texture and softness, and the fiber strength strength of the polylactic acid fiber contained in the woven fabric was 3.5 cN / dTex.
In addition, generation of isocyanate odor was not felt during melt-kneading and yarn production. Moreover, when the obtained structure was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
When the polylactic acid filament immediately after spinning was sampled, the carboxyl end group amount was 1 equivalent / ton, and the carboxyl end group amount of the fabric was 2 equivalent / ton.

[Example 2] Production of water-absorbing polylactic acid fiber structure 2:
It implemented like Example 1 except having used the stereocomplex polylactic acid chip | tip obtained by operation of the manufacture example 5, and the cyclic carbodiimide compound (CC2).
In the obtained woven fabric, warp density 140 / 2.54 cm, raw weft density 180 / 2.54 cm, thickness 0.5 mm, medium to low wetting feeling, water absorption 1.3 seconds, drying 71%, washing The durability was 31 times, the texture and softness, and the fiber strength strength of the polylactic acid fiber contained in the woven fabric was 3.6 N / dTex.
In addition, generation of isocyanate odor was not felt during melt-kneading and yarn production. Moreover, when the obtained structure was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
When the polylactic acid filament immediately after spinning was sampled, the carboxyl end group amount was 1 equivalent / ton, and the carboxyl end group amount of the fabric was 1 equivalent / ton.

[Example 3] Production of water-absorbing polylactic acid fiber structure 3:
In Example 2, the total fineness of 190 dtex composed of polyethylene terephthalate containing 3-carbomethoxy-benzenesulfonic acid Na-5-carboxylate Na (1.3 mol% based on dimethyl terephthalate) as a micropore forming agent as weft. / 48fil false twisted crimped yarn (1: 1 use) and just before dyeing, single weight fiber by alkali reduction in 35g / liter sodium hydroxide aqueous solution (temperature 95 ° C) The same procedure as in Example 2 was performed except that unevenness having a depth of about 0.01 to 10 μm was formed on the surface.
In the obtained woven fabric, the warp density is 140 pieces / 2.54 cm, the weft density of the raw machine is 180 pieces / 2.54 cm, the thickness is 0.5 mm, the wettability is minimal, the water absorption is 0.4 seconds, the drying property is 88%, and the washing durability. The texture was soft 49 times.
In addition, generation of isocyanate odor was not felt during melt-kneading and yarn production. Moreover, when the obtained structure was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
When the polylactic acid filament immediately after spinning was sampled, the carboxyl end group amount was 2 equivalent / ton, and the carboxyl end group amount of the fabric was 2 equivalent / ton.

[Example 4] Production of water-absorbing polylactic acid fiber structure 4:
Example 2 was the same as Example 2 except that the single-fiber cross-sectional shape of the false twist crimped yarn used as the weft was changed to a four-peak flat shape as shown in FIG.
In the obtained woven fabric, the warp density is 140 pieces / 2.54 cm, the weft density of the raw machine is 180 pieces / 2.54 cm, the thickness is 0.5 mm, the wettability is minimal, the water absorption is 0.3 seconds, the drying property is 89%, and the washing durability. The texture was soft 42 times.
In addition, generation of isocyanate odor was not felt during melt-kneading and yarn production. Moreover, when the obtained structure was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
When the polylactic acid filament immediately after spinning was sampled, the carboxyl end group amount was 2 equivalent / ton, and the carboxyl end group amount of the fabric was 2 equivalent / ton.

[Example 5] Production of water-absorbing polylactic acid fiber structure 5:
Example 2 was the same as Example 2 except that the square size of the checkered pattern was changed to 0.4 mm × 0.4 mm.
In the obtained woven fabric, warp density 140 / 2.54 cm, raw weft density 180 / 2.54 cm, thickness 0.5 mm, wet feeling, water absorption 1.8 seconds, drying 44%, washing durability 8 times, it was soft and soft.
In addition, generation of isocyanate odor was not felt during melt-kneading and yarn production. Moreover, when the obtained structure was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
When the polylactic acid filament immediately after spinning was sampled, the amount of carboxyl end groups was 2 equivalents / ton, and the amount of carboxyl end groups of the fabric was 3 equivalents / ton.

[Example 6] Production of water-absorbing polylactic acid fiber structure 6:
Example 2 was the same as Example 2 except that the square size of the checkered lattice pattern was changed to 3 mm × 3 mm (application area ratio 50%).
In the obtained woven fabric, warp density 140 / 2.54 cm, raw weft density 180 / 2.54 cm, thickness 0.5 mm, wet feeling, water absorption 1.9 seconds, drying 40%, washing durability Nine times, it was soft and soft.
In addition, generation of isocyanate odor was not felt during melt-kneading and yarn production. Moreover, when the obtained structure was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
When the polylactic acid filament immediately after spinning was sampled, the carboxyl end group amount was 2 equivalent / ton, and the carboxyl end group amount of the fabric was 2 equivalent / ton.

[Comparative Example 1]
In Example 1, it replaced with cyclic carbodiimide (CC1), and performed the same operation except having used the linear polycarbodiimide compound [The Nisshinbo Chemical Co., Ltd. product; "Carbodilite" HMV-8CA].
In the obtained woven fabric, warp density 140 / 2.54 cm, raw weft density 180 / 2.54 cm, thickness 0.5 mm, wet feeling, water absorption 2.0 seconds, drying 44%, washing durability 8 times, it was soft and soft.
When the polylactic acid filament immediately after spinning was sampled, the carboxyl end group amount was 2 equivalent / ton, and the carboxyl end group amount of the water-absorbent fabric was 2 equivalent / ton. It was. Moreover, when the obtained structure was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was unacceptable.

[Comparative Example 2]
In Example 1, the same operation was performed except that the cyclic carbodiimide (CC1) was not used.
In the obtained woven fabric, warp density 140 / 2.54 cm, raw weft density 180 / 2.54 cm, thickness 0.5 mm, wet feeling, water absorption 1.9 seconds, drying 40%, washing durability 7 times, texture and soft.
The generation of isocyanate odor was not felt during melt-kneading and spinning. When melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable, but when the polylactic acid filament immediately after spinning was sampled, the carboxyl end group amount was 29 equivalents / ton, and the carboxyl end group of the water-absorbent fabric was The amount was 38 equivalents / ton, which was inferior in hydrolyzability.

  According to the present invention, it is possible to provide a water-absorbing polylactic acid fiber structure in which hydrolysis resistance is improved and a free isocyanate compound is not generated.

Claims (22)

  A polylactic acid fiber structure comprising a polylactic acid fiber containing a polylactic acid and a compound (component C) containing a cyclic structure in which a single lactic acid and a carbodiimide group and the first nitrogen and the second nitrogen are bonded by a bonding group Water-absorbing polylactic acid fiber structure subjected to water-absorbing processing.   The water-absorbing polylactic acid fiber structure according to claim 1, wherein the number of atoms forming the cyclic structure of the C component is 8 to 50. The water-absorbing polylactic acid fiber structure according to claim 1 or 2, wherein the cyclic structure of component C is represented by the following formula (1).

(In the formula, Q is a divalent to tetravalent linking group that is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may contain a hetero atom.) The water-absorbing polylactic acid fiber structure according to claim 3, wherein Q is a divalent to tetravalent linking group represented by the following formula (1-1), (1-2) or (1-3).

(In the formula, Ar ¹ and Ar ² are each independently an aromatic group having 2 to 4 carbon atoms and 5 to 15 carbon atoms. R ¹ and R ² are each independently 1 to 2 carbon atoms having 1 to 4 carbon atoms. 20 aliphatic groups, 2 to 4 valent alicyclic groups having 3 to 20 carbon atoms, or combinations thereof, or these aliphatic groups, alicyclic groups and 2 to 4 valent aromatic carbon atoms having 5 to 15 carbon atoms X ¹ and X ² are each independently a divalent to tetravalent aliphatic group having 1 to 20 carbon atoms, a divalent to tetravalent carbon atom having 3 to 20 alicyclic groups, 2 to 4 A valent aromatic group having 5 to 15 carbon atoms, or a combination thereof, s is an integer of 0 to 10. k is an integer of 0 to 10. When s or k is 2 or more, X ¹ or X ² as a repeating unit may be different from other X ¹ or X ^2. X ³ is a divalent to tetravalent carbon number. An aliphatic group having 1 to 20 carbon atoms, an alicyclic group having 2 to 4 carbon atoms having 3 to 20 carbon atoms, an aromatic group having 2 to 4 carbon atoms having 5 to 15 carbon atoms, or a combination thereof, provided that Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ may contain a hetero atom, and when Q is a divalent linking group, Ar ¹ , Ar ² , R 3 ¹ , R ² , X ¹ , X ² and X ³ are all divalent groups, and when Q is a trivalent linking group, Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ^{One of 2} and X ³ is a trivalent group, and when Q is a tetravalent linking group, one of Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ One of them is a tetravalent group or two are trivalent groups.) The water-absorbing polylactic acid fiber structure according to claim 3, wherein the compound containing a cyclic structure of component C is represented by the following formula (2).

(In the formula, Qa is a divalent linking group that is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may contain a hetero atom.) The water-absorbing polylactic acid fiber structure according to claim 5, wherein Qa is a divalent linking group represented by the following formula (2-1), (2-2) or (2-3).

(In the formula, Ar _a ¹ , Ar _a ² , R _a ¹ , R _a ² , X _a ¹ , X _a ² , X _a ³ , s and k are represented by the formulas (1-1) to (1-3), respectively. The same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k in the inside.) The water-absorbing polylactic acid fiber structure according to claim 3, wherein the compound containing a cyclic structure of component C is represented by the following formula (3).

(Wherein Q _b is a trivalent linking group which is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may contain a hetero atom. Y represents a cyclic structure. It is a carrier to be supported.) Q _b is represented by the following formula (3-1), (3-2) or the water absorbent polylactic acid fiber structure according to claim 7 is a trivalent linking group represented by (3-3).

(In the formula, Ar _b ¹ , Ar _b ² , R _b ¹ , R _b ² , X _b ¹ , X _b ² , X _b ³ , s and k are represented by the formulas (1-1) to (1-3), respectively. Are the same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s, and k, with one of these being a trivalent group.)   The water-absorbing polylactic acid fiber structure according to claim 7 or 8, wherein Y is a single bond, a double bond, an atom, an atomic group or a polymer. The water-absorbing polylactic acid fiber structure according to claim 3, wherein the compound containing a cyclic structure of component C is represented by the following formula (4).

(Wherein Q _c is a tetravalent linking group that is an aliphatic group, an aromatic group, an alicyclic group, or a combination thereof, and may have a hetero atom. Z ¹ and Z ² are A carrier carrying a ring structure.) 11. The water-absorbing polylactic acid fiber structure according to claim 10, wherein Q _c is a tetravalent linking group represented by the following formula (4-1), (4-2), or (4-3).

(In the formula, Ar _c ¹ , Ar _c ² , R _c ¹ , R _c ² , X _c ¹ , X _c ² , X _c ³ , s and k are respectively represented by formulas (1-1) to (1-3) Are the same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k, provided that one of them is a tetravalent group or two are 3 Valent group.) The water-absorbing polylactic acid fiber structure according to claim 11, wherein Z ¹ and Z ² are each independently a single bond, a double bond, an atom, an atomic group or a polymer.   Content of C component is 0.001-10 weight part per 100 weight part polylactic acid, The water absorptive polylactic acid fiber structure in any one of Claims 1-12.   The water-absorbing polylactic acid fiber structure according to claim 1 or 2, wherein the polylactic acid fiber structure includes polyester fibers as other fibers.   The water-absorbing polylactic acid fiber structure according to any one of claims 1 to 14, wherein a single fiber cross-sectional shape of the polylactic acid fiber and / or the polyester fiber is atypical.   The water-absorbing polylactic acid fiber structure according to any one of claims 1 to 15, which has voids and / or cracks on a surface of a single fiber of the polylactic acid fiber and / or the polyester fiber.   The water-absorbing polylactic acid fiber structure according to any one of claims 1 to 16, wherein the polylactic acid fiber structure is a woven fabric or a knitted fabric.   The water-absorbing polylactic acid fiber structure according to claim 17, wherein the water-repellent process is performed only on one side of the fiber structure following the water absorption process.   The water-absorbing polylactic acid fiber structure according to claim 17, wherein the water-repellent agent is partially attached to one side of the fiber structure in a pattern in which the polygon has a portion where corners are continuous.   The water-absorbing polylactic acid fiber structure according to claim 19, wherein the water absorption rate measured by JIS L-1018A method (drop method) is 5 seconds or less.   The water-absorbing polylactic acid fiber structure according to any one of claims 17 to 20, wherein a fiber strength of the polylactic acid fiber fiber contained in the polylactic acid fiber structure is 2.3 cN / dtex or more.   A textile product selected from the group consisting of sports apparel, inner apparel, men's apparel, and women's apparel comprising the water-absorbing polylactic acid fiber structure according to any one of claims 1 to 21.

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