JP4981721B2 - Method for producing heat-retaining polylactic acid fiber structure, heat-retaining polylactic acid fiber structure and fiber product - Google Patents

Description

  The present invention provides a method for producing a heat-retaining polylactic acid fiber structure in which not only has excellent heat retention but also polylactic acid fibers contained in the fiber structure have excellent strength, and heat-retaining polylactic acid fiber structure, and It relates to textile products.

  In recent years, for the purpose of protecting the global environment, biodegradable polymers that are decomposed in a natural environment have attracted attention and are being studied all over the world. Known biodegradable polymers include polyhydroxybutyrate, polycaprolactone, aliphatic polyester, polylactic acid, and the like. Among them, polylactic acid is being studied as a general-purpose polymer in consideration of the global environment, not just as a biodegradable polymer, because lactic acid or lactide, which is a raw material for polylactic acid, can be produced from natural products. Biodegradable polymers such as polylactic acid are highly transparent and tough, but they are easily hydrolyzed in the presence of water and decompose without polluting the environment after disposal. Expected. And the polylactic acid fiber which consists of this polylactic acid is widely used as clothing, interior products, etc. (for example, refer patent document 1, patent document 2).

It is also known to add heat retention to a polylactic acid fiber structure using an infrared absorber (see, for example, Patent Document 3).
However, the polylactic acid fiber structure has a problem that the fiber strength of the polylactic acid fiber contained in the fiber structure is low.
In addition, it is known by patent document 4 etc. to raise heat retention property by making an infrared absorber adhere partially in a fiber structure.

JP 2003-105629 A Japanese Patent No. 3731432 JP 2004-100101 A Japanese Patent No. 3853175

  The present invention has been made in view of the above-mentioned background, and the object thereof is not only to have excellent heat retention, but also to heat retention polylactic acid fiber structure in which the polylactic acid fiber contained in the fiber structure has excellent strength. It is in providing the heat retention polylactic acid fiber structure obtained by this manufacturing method, and the fiber product using this heat retention polylactic acid fiber structure.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that poly L-lactic acid (A component) and poly D-component (B component) are present in the presence of a specific phosphate ester metal salt (C component). It has been found that a desired heat-retaining polylactic acid fiber structure can be obtained by obtaining a fiber structure using polylactic acid fibers obtained by spinning and stretching, and attaching an infrared absorber to the fiber structure. The present invention has been completed by further intensive studies.

Thus, according to the present invention, “a method for producing a heat-retaining polylactic acid fiber structure in which an infrared absorber is attached to a polylactic acid fiber structure containing polylactic acid fiber, wherein the polylactic acid fiber is (i) poly L -Lactic acid (A component), (ii) Poly D-lactic acid (B component) and (iii) 0.05-5 parts by weight of the following formula (1) or (2) per 100 parts by weight of the total of A component and B component consists polylactic acid composition containing phosphoric ester metal salt (C component) represented by),
And the fiber strength of the polylactic acid fiber is 2.3 cN / dtex or more,
The polylactic acid fiber melt-spins the polylactic acid composition to obtain an undrawn yarn, the step of obtaining an undrawn yarn at 70 to 140 ° C., and the step of heat treating the drawn yarn at 170 to 220 ° C. A method for producing a heat-retaining polylactic acid fiber structure, which is a fiber obtained by the method described above. Is provided.

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

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

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

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

At that time, the polylactic acid composition contains 0.1 to 5 parts by weight of a carboxyl terminal blocking agent per 100 parts by weight in total of the poly L-lactic acid component (component A) and the poly D-lactic acid component (component B). It is preferable to contain. The polylactic acid fiber structure preferably includes polyester fibers as other fibers. The polylactic acid fiber structure is preferably a woven fabric or a knitted fabric. The infrared absorber is preferably an infrared absorber made of antimony-doped tin oxide or tin-doped indium oxide. Moreover, it is preferable that the adhesion amount of the said infrared absorber exists in the range of 0.02-50gr / m < ² > with respect to a fiber structure.

  In the method for producing a heat-retaining polylactic acid fiber structure of the present invention, the infrared absorber has an application part and a non-application part on at least one surface of the polylactic acid fiber structure, and the application part surrounds the non-application part. It is preferable to adhere in a continuous pattern. In that case, it is preferable that this pattern is a lattice pattern. Moreover, it is preferable to attach an infrared absorber only to one surface of the polylactic acid fiber structure.

Moreover, according to this invention, the heat retention polylactic acid fiber structure manufactured by the said manufacturing method is provided .

  In addition, according to the present invention, there is provided any fiber product selected from the group consisting of sports apparel, inner apparel, men's apparel, and women's apparel, using the heat-retaining polylactic acid fiber structure.

  According to the present invention, a method for producing a heat-retaining polylactic acid fiber structure having not only excellent heat retention but also having excellent strength in the polylactic acid fiber contained in the fiber structure, and the production method A heat-retaining polylactic acid fiber structure and a fiber product using the heat-retaining polylactic acid fiber structure are obtained.

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

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

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

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

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

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

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

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

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

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

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

In Formula (1), R ₁ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms represented by R ₁ include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, and an iso-butyl group. The

R ₂ and R ₃ each independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, sec-butyl group, iso-butyl group, tert-butyl group, amyl group, tert-amyl group, hexyl group, heptyl group, octyl group, iso-octyl group, tert-octyl group, 2-ethylhexyl group, nonyl group, iso-nonyl group, decyl group, iso-decyl group, tert-decyl group, An undecyl group, a dodecyl group, a tert-dodecyl group, etc. are mentioned.

M ₁ represents an alkali metal atom such as Na, K or Li or an alkaline earth metal atom such as Mg or Ca. p represents 1 or 2.
Preferable examples of the phosphoric acid ester metal salt represented by the formula (1) include those in which R ₁ is a hydrogen atom and R ₂ and R ₃ are both tert-butyl groups.

In the formula (2), R ₄ , R ₅ and R ₆ each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, sec-butyl group, iso-butyl group, tert-butyl group, amyl group, tert-amyl group, hexyl group, heptyl group, octyl group, iso-octyl group, tert-octyl group, 2-ethylhexyl group, nonyl group, iso-nonyl group, decyl group, iso-decyl group, tert-decyl group, An undecyl group, a dodecyl group, a tert-dodecyl group, etc. are mentioned.
M ₂ represents an alkali metal atom such as Na, K or Li or an alkaline earth metal atom such as Mg or Ca. p represents 1 or 2.

Preferred examples of the phosphoric acid ester metal salt represented by the formula (2) include those in which R ₄ and R ₆ are methyl groups and R ₅ is a tert-butyl group. As a phosphoric acid ester metal salt, trade name, NA-11, manufactured by ADEKA Co., Ltd. can be mentioned. The phosphoric acid ester metal salt can be synthesized by a known method.

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

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

  The content of the phosphoric acid ester metal salt (component C) is 0.01 to 5 parts by weight per 100 parts by weight in total of the poly L-lactic acid (component A) and the poly D-lactic acid (component B), preferably 0.00. 05 to 5 parts by weight, more preferably 0.05 to 4 parts by weight, particularly preferably 0.1 to 3 parts by weight. If the amount is less than 0.01 parts by weight, the desired effect is hardly recognized. On the other hand, if it is used in a larger amount than 5 parts by weight, it is not preferable because thermal decomposition or fiber breakage may occur during fiber formation.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  Furthermore, it is preferable to heat-treat the drawn yarn. The heat treatment is performed at 170 to 220 ° C. (preferably 180 to 200 ° C.). The heat treatment is preferably performed under tension. The heat treatment can be performed with a hot roller, a contact heater, a non-contact hot plate or the like. By heat-treating, a fiber having a high stereo ratio, 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. Further, the single fiber cross-sectional shape of the polylactic acid fiber and / or the polyester fiber is not particularly limited, and may be any of a normal round cross section, a round hollow cross section, a triangular cross section, a square cross section, a flat cross section, and a constricted flat cross section. A non-round cross-section is preferred because it improves 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.

  Further, the structure of the fiber structure is not particularly limited and may be in the form of a yarn, but is preferably a woven fabric or a knitted fabric knitted or woven 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, an infrared absorber is adhered to the fiber structure. Here, when the fiber structure is a fabric such as a woven fabric or a knitted fabric, an infrared absorber is attached to at least one surface of the fabric. In that case, normally, an infrared absorber is made to adhere to a cloth by binder resin. The infrared absorbent and the binder resin may be attached to both sides of the fabric, but it is preferable to attach only to one side. Even when the infrared absorber and the binder resin are colored by attaching only to one surface and making the surface the back surface, that is, the surface that becomes the skin side of the human body when such fabric is used for clothing, Since these agents and resins do not appear on the surface of the fabric, there is no risk of appearance problems. Furthermore, since the infrared absorber is attached only to the back surface, heat is not easily transmitted from the back surface of the fabric to the front surface, so that effective heat retention is possible. Furthermore, when polylactic acid fibers are contained in the fiber structure as in the present invention, the polylactic acid fibers are more excellent in light transmission than ordinary polyester fibers such as polyethylene terephthalate fibers. Easily absorbs infrared rays and provides excellent heat retention.

  The infrared absorber is not particularly limited as long as it is a substance having an absorptance of 10% or more in an infrared region having a wavelength of 700 to 2000 nm, and examples thereof include metal oxide fine particles, carbon black, and infrared absorbing dyes of organic compounds. Is done. Among these infrared absorbers, those having a thermal conductivity of 10 W / m · K (27 ° C.) or more (more preferably 20 W / m · K or more) are preferable. By having such thermal conductivity, when the infrared absorbent is warmed by infrared rays such as sunlight, the fabric is warmed very quickly, and excellent heat retaining properties are easily obtained. Specifically, metal oxide fine particles having an average particle diameter of 100 nm or less such as antimony-doped tin oxide (ATO) and tin-doped indium oxide (ITO) are preferably exemplified. Such metal oxide fine particles are also a transparent material that transmits visible light, and are preferable in that they do not change the hue of the fabric body. This kind of metal oxide fine particles can be obtained as an aqueous dispersion or a solvent dispersion such as toluene. Further, when the hue of the fabric is a dark color product such as black, navy blue, and engineering color, carbon black can also be suitably used, and the particle size of the carbon black is about several μm. I just need it. Note that when carbon black is applied to a light-colored fabric, the fabric surface tends to become gray.

The amount of the infrared absorbing agent fixed to the fabric is preferably in the range of 0.02 to 50 g / m ² (more preferably 0.5 to 20 g / m ² ) with respect to the fabric. If the adhesion amount of the infrared absorber is less than the above range, the fabric may not be sufficiently warmed even when the fabric is exposed to infrared rays such as sunlight. On the contrary, if the amount of the infrared absorber attached is larger than the above range, the heat retaining effect is sufficient, but it is not economical.

The binder resin that can be used in the present invention is not particularly limited, and examples thereof include urethane resins, acrylic resins, polyester resins, silicone resins, vinyl chloride resins, and nylon resins. The adhesion amount of the binder resin is preferably in the range of 0.01 to 40 g / m ² (more preferably 5 to 30 g / m ² ) with respect to the fabric based on the resin solid content.

  Usually, the said infrared absorber and binder resin are provided to a fiber structure as a compounding composition of both. In this case, the blended composition may be composed of either an aqueous system or a solvent system, but an aqueous system is preferable in view of the working environment of the processing step. Examples of the solvent include toluene, isopropyl alcohol, dimethylformamide, methyl ethyl ketone, ethyl acetate and the like. This blended composition may be used in combination with an epoxy-based crosslinking agent. Furthermore, you may further mix | blend an appropriate additive for the objective of improving the adhesiveness with respect to a fiber structure main body.

  The blending ratio of the infrared absorber to the binder resin (resin solid content basis) is preferably in the range of 1: 0.5 to 1:50 (preferably 1: 5 to 1:40). If the blending ratio of the binder resin is less than the above range, the infrared absorbent is likely to fall off during washing after the fiber structure is made into a product. On the contrary, even if the blending ratio of the binder resin is larger than the above range, the effect of washing durability is not changed so much and it is not economical.

Next, in the present invention, the infrared absorbent is preferably attached to the fiber structure (fabric) in a pattern having a coating part and a non-coating part, and the coating part surrounding the non-coating part. In particular, it is preferable that the entire area of the pattern is a lattice pattern, by adopting such a lattice pattern, when the infrared absorber is heated by infrared rays such as solar rays, the heat is along the lattice pattern, It is transmitted quickly and the fiber structure is quickly warmed. Moreover, it is preferable that the application part area ratio in a pattern is 10 to 85% (preferably 25 to 70%). In addition, an application part area ratio is shown by a following formula.
Application part area ratio = (application part area) / (application part area + non-application part area) × 100 (%)

  If the coated area ratio is less than 10%, the fabric may not be sufficiently warmed even when the fiber structure (fabric) is irradiated with infrared rays. On the other hand, when the application area ratio is larger than 85%, the texture of the fiber structure (fabric) may be lowered. In the lattice pattern, the interval between the lattices is suitably about 2 to 30 mm.

  As a means for imparting an infrared absorber and a binder resin to a fiber structure, first, both are made into a blended composition as described above, and then the blended composition is a known one such as a gravure coating method or a screen printing method. Giving means can be used.

  In addition, in the process before and / or after the infrared absorber application process, conventional dyeing process, alkali weight reduction process, water repellent process, brushed process, ultraviolet shielding or antibacterial agent, deodorant, insect repellent, phosphorescent agent, Various processes that provide functions such as a retroreflective agent and a negative ion generator may be additionally applied.

  In the heat-retaining polylactic acid fiber structure thus obtained, since the fiber structure contains polylactic acid fibers that are easily transmitted through the infrared absorber, the sun rays are easily transmitted through the fiber structure. When the infrared absorber is heated, excellent heat retention is obtained. At the same time, since the polylactic acid fiber contained in the fiber structure is a polylactic acid fiber as described above, it has excellent fiber strength. The fiber strength is preferably 2.3 cN / dtex or more (more preferably 3 to 10 cN / dtex). However, the fiber strength in the present invention was determined by using “Tensilon” (trade name) manufactured by Orientic Corporation, and randomly extracting 10 target single yarns (filaments) from the fiber structure to be measured, 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 length between chucks) and elongation rate of 500 mm / min, and the strength (cN / piece) was obtained from the stress and elongation at the breaking point. Then, 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 above heat-retaining polylactic acid fiber structure. Such a fiber product contains the above heat-retaining polylactic acid fiber structure, so that it exhibits excellent heat-retaining properties and at the same time, the fiber strength of the poly milk fiber contained in the fiber product is high.

  In addition, the heat-retaining polylactic acid fiber structure includes vehicle interior materials such as car seat skin materials, floor materials, and ceiling materials, clothing materials such as cups and pads, curtains, carpets, mats, furniture other than the above-described fiber products. Interior materials such as belts, nets, ropes, heavy cloth, bags, felts, filters, etc., accessories, form straps, wipe glasses, tableware wipes, mouse pads, stuffed animals, toys, hats, gloves, whiteboards It is also suitably used as small items such as cleaners and notebook covers.

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

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

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

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

(4) Fiber strength (cN / dtex)
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).

(5) Thermal insulation To confirm the thermal insulation effect, the surface temperature of the fabric after 30 seconds was irradiated from a height of 50 cm using a 200 W reflex lamp light source as an energy source in a constant temperature and humidity environment of 20 ° C. and 60% RH. Was measured with a thermoviewer (infrared sensor: manufactured by JEOL Ltd.) and the temperature of the back surface of the fabric was measured with a thermocouple.

(6) Texture evaluation A sensory evaluation was performed on the soft feeling by three testers and evaluated in four stages. “Excellent” is indicated by ◎, “Excellent” is indicated by ○, “Normal” is indicated by △, and “Inferior” is indicated by ×.

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

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

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

[Example 1]
The stereocomplex polylactic acid resin obtained in Production Example 3 was dried at 110 ° C. for 2 hours and at 150 ° C. for 5 hours to give a moisture content of the resin of 80 ppm, and then a spinneret having 36 holes of 0.27 φmm was formed. The undrawn yarn was wound up at a speed of 500 m / min after spinning at a spinning temperature of 255 ° C. and a discharge rate of 8.35 g / min. The wound undrawn yarn was drawn 4.9 times with a drawing machine at 80 ° C. by preheating to wind the drawn yarn, and then heat treated at 180 ° C. The obtained yarn is a multifilament having a fineness of 56 dTex / 20 fil (single fiber cross-sectional shape is a round cross-section), and has a single melting peak in DSC measurement. The melting peak temperature (melting point) is 224 ° C. Yes, the stereo ratio was 100%.

  In addition, the stereocomplex polylactic acid resin obtained in Production Example 3 was similarly obtained to obtain a multifilament having a fineness of 84 dTex / 36 fil (single fiber cross-sectional shape is a round cross section). The multifilament had a single melting peak in DSC measurement, the melting peak temperature (melting point) was 224 ° C., and the stereoization rate was 100%.

Subsequently, a multifilament having a total fineness of 56 dtex / 20 fil is used as a warp, and a multifilament having a total fineness of 84 dtex / 36 fil is used as a weft to obtain a taffeta fabric having a warp density of 76 / 2.54 cm and a weft density of 90 / 2.54 cm. It was.
The taffeta fabric was refined, relaxed and dyed in a conventional manner, dried and set to obtain a base fabric.

Moreover, the following compounding composition was prepared for heat retention provision.
[Composition of compounding composition]
・ Acrylic binder 60.0%
(Solid content 40%)
-ATO aqueous dispersion 5.0%
(Solid content 15%, ATO thermal conductivity 50 W / m · K, ATO fine particle diameter 50 nm or less)
・ Water 35.0%

Next, the above composition was applied to one side of a taffeta fabric using a 105 mesh gravure roll (ATO content 0.8 g / m ² , binder resin solid content 24.2 g / m ² ), and then dried at 160 ° C. Thus, a heat insulating fabric (heat insulating polylactic acid fiber structure) was obtained. As the gravure roll transfer pattern, the entire surface was formed in a vertical and horizontal grid pattern (applied portion area ratio 50%, interval between grids 10 mm) shown in FIG. In the obtained heat retaining fabric, the heat retaining property was 38.1 ° C. at the temperature of the fabric surface, 39.6 ° C. at the temperature of the back surface of the fabric, soft feeling ○, fiber strength of warp yarn 3.6 cN / dTex, fiber strength of weft yarn 3 The fiber strength of .7 cN / dTex and polylactic acid fiber was excellent, and the heat retention was also excellent.

[Example 2]
In Example 1, the transfer pattern of the gravure roll was the same as Example 1 except that the coating part area ratio was 100% as shown in FIG. 3 (ATO content 1.6 g / m ² , Binder resin solid content 48.4 g / m ² ). In the obtained heat-retaining fabric, the heat-retaining property was 38.5 ° C. at the temperature of the fabric surface, 39.8 ° C. at the temperature of the back surface of the fabric, and the soft feeling and the heat-retaining property were excellent, but the soft feeling was insufficient. Met.

[Comparative Example 1]
In Example 1, it carried out similarly to Example 1 except having changed all the fibers used to a normal polyethylene terephthalate. In the obtained heat retaining fabric, the heat retaining property was 38.2 ° C. at the temperature of the fabric surface, 39.2 ° C. at the temperature of the back surface of the fabric, soft feeling, fiber strength of warp yarn 3.6 cN / dTex, fiber strength of weft yarn 3 .7 cN / dTex, which was inferior to Example 1 in terms of heat retention.

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

[Comparative Example 3]
In Example 1, it carried out similarly to Example 1 except changing content of a phosphoric acid ester metal salt into 0 weight part. In the obtained woven fabric, the fiber strength strength of the polylactic acid fiber contained in the woven fabric was warp 1.8 cN / dTex and weft 1.8 cN / dTex.

  According to the present invention, a method for producing a heat-retaining polylactic acid fiber structure having not only excellent heat retention but also having excellent strength in the polylactic acid fiber contained in the fiber structure, and the production method A heat-retaining polylactic acid fiber structure and a fiber product using the heat-retaining polylactic acid fiber structure are provided, and its industrial value is extremely large.

In an Example, an example of the diffraction intensity profile of the equatorial direction for calculating | requiring a stereoization rate (Sc rate) is shown. 2 is a schematic diagram of a vertical and horizontal grid pattern used in Example 1. FIG. In addition, a black part shows an application part. 6 is a schematic diagram of a pattern applied to the entire surface used in Example 2. FIG.

Claims (11)

A method for producing a heat-retaining polylactic acid fiber structure in which an infrared absorbent is adhered to a polylactic acid fiber structure containing polylactic acid fibers, wherein the polylactic acid fiber is (i) poly L-lactic acid (component A), ( ii) Poly D-lactic acid (component B) and (iii) 0.05 to 5 parts by weight of a phosphate metal represented by the following formula (1) or (2) per 100 parts by weight of the total of component A and component B A polylactic acid composition containing a salt (component C) ,
And the fiber strength of the polylactic acid fiber is 2.3 cN / dtex or more,
The polylactic acid fiber melt-spins the polylactic acid composition to obtain an undrawn yarn, the step of obtaining an undrawn yarn at 70 to 140 ° C., and the step of heat treating the drawn yarn at 170 to 220 ° C. A method for producing a heat-retaining polylactic acid fiber structure, which is a fiber obtained by the method described above.

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

In the formula, each of R ₄ , R ₅ and R ₆ independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, M ₂ represents an alkali metal atom or an alkaline earth metal atom, and p represents 1 or 2 Represents.   The polylactic acid composition contains 0.1 to 5 parts by weight of a carboxyl terminal blocking agent per 100 parts by weight in total of a poly L-lactic acid component (A component) and a poly D-lactic acid component (B component). The method for producing a heat-retaining polylactic acid fiber structure according to claim 1.   The method for producing a heat-retaining polylactic acid fiber structure according to claim 1 or 2, wherein the polylactic acid fiber structure includes polyester fibers as other fibers.   The method for producing a heat-retaining polylactic acid fiber structure according to any one of claims 1 to 3, wherein the polylactic acid fiber structure is a woven fabric or a knitted fabric.   The manufacturing method of the heat retention polylactic acid fiber structure in any one of Claims 1-4 whose said infrared absorber is an infrared absorber which consists of antimony dope tin oxide or tin dope indium oxide. The manufacturing method of the heat retention polylactic acid fiber structure of Claim 4 whose adhesion amount of the said infrared absorber exists in the range of 0.02-50gr / m < ² > with respect to a fiber structure.   5. The heat retaining material according to claim 4, wherein the infrared absorbent is attached to at least one surface of the polylactic acid fiber structure in a pattern having a coating portion and a non-coating portion, and the coating portion surrounding the non-coating portion and being continuous. For producing a conductive polylactic acid fiber structure.   The method for producing a heat-retaining polylactic acid fiber structure according to claim 7, wherein the pattern is a lattice pattern.   The method for producing a heat-retaining polylactic acid fiber structure according to claim 4, wherein the infrared absorbent is attached only to one surface of the polylactic acid fiber structure.   A heat-retaining polylactic acid fiber structure produced by the production method according to claim 1. A textile product selected from the group consisting of sports garments, inner garments, men's garments, and women's garments, wherein the heat-retaining polylactic acid fiber structure according to claim 10 is used.

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