JP2011058120A - Spun-like polylactic acid composite false-twisted yarn and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spun-like polylactic acid composite false twisted yarn having a spun-like polylactic appearance. <P>SOLUTION: A filament yarn whose elongation is small configures a core portion, and the filament yarn whose elongation is larger than that of the core portion filament yarn configures the outer layer portion by surrounding the boundary of the core portion like an alternate yarn and a portion of both the filament yarns coexist and cross at a boundary portion between the core portion and the outer layer portion, and a confounding portion is formed so that a two-layer structure false-twisted yarn can be configured. One filament yarn contains specific phosphate metal salt so that a spun-like polylactic acid false-twisted yarn as a polylactic acid fiber can be configured. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a false twisted two-layer structure yarn (composite braided yarn) having a spun-like appearance and texture from an environment-friendly non-petroleum-derived polymer and a method for producing the same.

  As global warming is progressing due to excessive consumption of petroleum resources and deforestation is further accelerated, switching to renewable resources is strongly desired. Among them, polylactic acid fiber is derived from plant materials, has physical properties similar to those of polyester fiber, which is widely used as general-purpose synthetic fiber, and can be melt-spun and biodegradable after use, as a synthetic fiber derived from non-petroleum resources There are great expectations.

  Also, if two or more types of yarns with different elongations are combined, supplied to the supply roller, and twisted with a false twist spindle, the yarns with low elongation are difficult to stretch. Since a yarn having a large elongation is easily stretched, it is twisted so as to surround the outer layer portion of the yarn. When the twisted state is heat-fixed and then untwisted, a yarn having a low elongation becomes a core, and a yarn having a high elongation is obtained as a false-twisted two-layer structure yarn in which surrounding yarns are alternately twisted. . The term “yarn” refers to filament yarn unless otherwise stated.

  It is already known that these yarns can be produced using general-purpose polyester (polyethylene terephthalate), and commercial production is widely conducted both domestically and abroad, but it is derived from petroleum resources and costs due to resource depletion in the future. It was not possible to satisfy consumer needs due to high concerns and above all, the increase in environmental awareness.

  On the other hand, various production technologies have been reported as commercialization of polylactic acid fibers, but it has been achieved that false twisted yarn can be manufactured in a balanced and stable manner and at a cost comparable to general-purpose polyester. Was not. In particular, polylactic acid fibers have a remarkably environmental change in the spinning yarn in the non-oriented state, and it is necessary to reach the partial orientation at the spinning stage, so that the non-oriented yarn cannot be stably obtained. A false twisted two-layer structure yarn surrounded by a twisted yarn is difficult to produce and has not been produced satisfactorily.

JP 54-18947 A JP 63-24014 A JP 2003-293220 A Japanese Patent Laid-Open No. 2005-23512

  A polylactic acid composite false twisted yarn (false twisted two-layer structure yarn) having a spun-like appearance and a method for stably and commercially producing the yarn are provided.

The above problems are solved by the following means.
That is, according to the present invention,
A filament yarn having a low elongation constitutes a core portion, and a filament yarn having a higher elongation than the core portion filament yarn surrounds the core portion in an alternating twisted manner to form an outer layer portion, A two-layer structure false twisted yarn in which a part of both filament yarns are mixed with each other at the boundary portion of the outer layer portion and crossed to form an entangled portion, and a spun-like polylactic acid false twist yarn satisfying the following requirements:
a) At least one of the filament yarns is a polylactic acid fiber.
b) The elongation of the filament yarn in the core portion is 25% or more, and the elongation of the filament yarn in the outer layer portion is 45% or more.
c) a polylactic acid fiber (i) a poly L-lactic acid (component A) having a weight average molecular weight of 100,000 to 200,000, (ii) a poly D-lactic acid (component B) having a weight average molecular weight of 100,000 to 200,000, and (iii) ) It consists of a composition containing 0.01 to 5 parts by weight of a phosphoric acid ester metal salt (C component) per 100 parts by weight of the total of component A and component B, and has a melting point of 200 ° C. or higher.
Further, a method for producing the above spun-like polylactic acid false twisted yarn, wherein the difference in elongation between the filament yarn having low elongation and the filament yarn having high elongation is 40% or more,
Is provided.

  Two layers of polylactic acid filament yarns with different elongations are false twisted so that a low elongation yarn is a core yarn and a high elongation yarn is a sheath yarn (outer layer yarn). A twisted yarn is obtained. By using a composition comprising poly L lactic acid and poly D lactic acid containing a specific phosphoric ester metal salt, the false twisted yarn can be obtained.

It is the schematic which shows the one aspect | mode of the false twisting apparatus which implements this invention.

(Poly L-lactic acid: A component)
Poly L-lactic acid mainly consists of L-lactic acid units. The L-lactic acid unit is a repeating unit derived from L-lactic acid. The poly L-lactic acid preferably contains 90 to 100 mol%, more preferably 95 to 100 mol%, 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 preferably has crystallinity. The melting point is preferably 150 to 190 ° C, more preferably 160 to 190 ° C. This is because, if these conditions are satisfied, a stereocomplex crystal having a high melting point can be formed and the crystallinity can be increased.
The poly L-lactic acid has a weight average molecular weight of preferably 50,000 to 300,000, more preferably 100,000 to 250,000.

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

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

The poly D-lactic acid preferably has crystallinity. The melting point is preferably 150 to 190 ° C, more preferably 160 to 190 ° C. This is because, if these conditions are satisfied, a stereocomplex crystal having a high melting point can be formed and the crystallinity can be increased.
Poly D-lactic acid has a weight average molecular weight of preferably 100,000 to 200,000, more preferably 110,000 to 170,000.

  Poly-L-lactic acid or poly-D-lactic acid is produced by a method of directly dehydrating condensation of L-lactic acid or D-lactic acid, or L-lactic acid or D-lactic acid is once subjected to dehydration cyclization to form lactide, followed by ring-opening polymerization. It can be manufactured by a method. 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 include calcium compounds and lanthanide compounds.

  For poly L-lactic acid and poly D-lactic acid, it is preferable that the polymerization catalyst used in the polymerization is washed away with a solvent 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 and poly D-lactic acid 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.

(Phosphate metal salt: C component)
As the phosphoric acid ester metal salt (component C), a compound represented by the following formula (1) or (2) is preferably exemplified. 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. M1 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. M2 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. When the particle size is less than 0.01 μm, it is industrially difficult and it is not necessary to make it very small. If it exceeds 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 composition thus obtained can be melt-mixed and transferred to the spinning device as it is or via a metering pump. 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.
The composition may contain a carbodiimide compound. Thermal decomposition and hydrolysis resistance obtained by containing a carbodiimide compound are improved.

  As carbodiimide compounds, dicyclohexylcarbodiimide, diisopropylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, octyldecylcarbodiimide, di-tert-butylcarbodiimide, dibenzylcarbodiimide, diphenylcarbodiimide, N-octadecyl-N′-phenylcarbodiimide, N-benzyl-N ′ -Phenylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, di-o-toluylcarbodiimide, di-p-toluylcarbodiimide, bis (p-aminophenyl) carbodiimide, bis (p-chlorophenyl) carbodiimide, bis (o-chlorophenyl) ) Carbodiimide, bis (o-ethylphenyl) carbodiimide, bis (p-ethylphenyl) carbodiimi Bis (o-isopropylphenyl) carbodiimide, bis (p-isopropylphenyl) carbodiimide, bis (o-isobutylphenyl) carbodiimide, bis (p-isobutylphenyl) carbodiimide, bis (2,5-dichlorophenyl) carbodiimide, 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-tert-butylphenyl) carbodiimide, bis (2,4,6-trimethylphenyl) carbodiimide, bis (2,4,6-triisopropylphenyl) Carbodiimide, bis (2,4,6-tributylphenyl) carbodiimide, diβ-naphthylcarbodiimide, N-tolyl-N′-cyclohexylcarbodiimide, N-tolyl-N′-phenylcarbodiimide, p-phenylenebis (o-toluylcarbodiimide) P-phenylenebis (cyclohexylcarbodiimide, p-phenylenebis (p-chlorophenylcarbodiimide), 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide, hexamethylenebis (cyclohexylcarbodiimide), ethylenebis (phenylcarbodiimide), Examples thereof include mono- or polycarbodiimide compounds such as ethylenebis (cyclohexylcarbodiimide).

  Examples of such commercially available polycarbodiimide compounds include Carbodilite LA-1 and HMV-8CA sold under the trade name of Carbodilite sold by Nisshinbo Co., Ltd.

  The composition preferably has a decrease in weight average molecular weight of 20% or less when melted at 260 ° C. When the molecular weight is drastically reduced at high temperatures, spinning is not only difficult, but physical properties of the obtained yarn are lowered, which is not preferable.

  The composition preferably has a moisture content of 100 ppm or less. When the moisture content is high, hydrolysis of the poly-L-lactic acid component and the poly-D-lactic acid component is promoted, the molecular weight is remarkably lowered, and not only spinning becomes difficult, but physical properties of the obtained yarn are lowered, which is not preferable. .

  Further, the amount of residual lactide in the composition is preferably 3,000 ppm or less, more preferably 1,000 ppm or less, and particularly preferably 400 ppm or less. Since lactide in the polylactic acid obtained by the lactide method may vaporize during melt spinning and cause yarn unevenness, it is preferable for the purpose of obtaining a good yarn to suppress the lactide amount to 400 ppm or less.

(Outer layer yarn production method)
The polylactic acid obtained as described above is produced by a known method. For example, the obtained polylactic acid is extruded into a fiber form in a molten state, melt-spun at a speed of 500 to 3500 m / min, stretched and heat treated, melt-spun at a speed of 1000 to 5000 m / min, and stretched Preferred examples include a method of melt spinning at a high speed of 5000 m / min or more and omitting the stretching step depending on the application.
The elongation of the polylactic acid fiber of the outer layer yarn is preferably 45% or more. If it is less than 45%, the spanlike property cannot be obtained, which is not preferable.

  The single fiber fineness of the outer layer part yarn of the present invention is preferably 10 dtex or less. When it exceeds 10 dtex, it is difficult to obtain a core-sheath structure at the time of fiber mixing. On the other hand, the lower limit of the single fiber fineness is not particularly limited, but is preferably 0.1 dtex or more from the viewpoint that fibers can be formed practically and the wear resistance of the fabric is not significantly impaired.

  The cross-sectional shape of the single fiber of the outer layer yarn of the present invention can be any shape depending on the application and the like, for example, in addition to a circular shape, a modified cross-section such as a triangle, a flat shape, a star shape, a V shape, etc. A cross section can be illustrated.

(Core yarn)
Next, the core yarn of the two-layer structured yarn of the present invention is preferably a polylactic acid fiber, and preferably has an elongation of 25% or less. If it exceeds 25%, the spanlike property cannot be obtained, which is not preferable.

(Producing method of false twisted yarn)
In order to obtain a false twisted yarn with good spun-like properties, it is preferable that the difference in elongation between the core yarn and the outer layer yarn is 40% or more. If the difference in elongation is less than 40%, the spanlike property is lowered, which is not preferable. The difference in elongation between the core yarn and the outer layer yarn is preferably 50% or more, more preferably 80% or more.

  In order to obtain a core-sheath two-layer structure false twisted yarn, the above-described core yarn and outer layer yarn (also referred to as sheath yarn) are aligned, subjected to an air entanglement treatment, and then drawn false twisted with a non-contact heater. It is obtained by going through. In this case, the use ratio of both may be core yarn: sheath yarn = 25: 75 to 75:25 (weight). The air entanglement may be either interlaced or Taslan processing. Specifically, the process of FIG. 1 can be shown.

  Here, if heat treatment is performed with a heater while overfeeding after the confounding is applied, the core yarn shrinks and the sheath yarn hardly shrinks or self-extends, and there is a difference in the thread foot between the core yarn and the sheath yarn. When used as a fabric, it leads to swelling and span-like properties.

The measuring method is as follows.
・ Strength of fiber:
It measured based on the method of JISL-1013 description.
・ Spanlike evaluation:
Span-like property was evaluated according to the following measurement method. That is, the obtained false twisted yarn is made by taking 120 rotations with a measuring scale (circumferential length: 1.125 m) to make a cocoon, and a load three times the weight of the cocoon is applied to one end of the folded sample. It was hung and heat-treated at 195 ° C. for 5 minutes and then cooled. Next, the yarn is filled into a box (height 2.5 cm, width 1.0 cm, length 10 cm, bottom surface radius 0.5 cm) and a lid (three times the weight of the heel) is loaded, and the volume at that time It was calculated by the following formula from (Vcm ³ ) and the weight (Wg) of the kite (false twisted yarn).
Spanlike property (cm ³ / g) = V / W
When this value was 50 or more, the spanlike property was “◯”, and when it was less than 50, it was “x”.

(Raw material preparation)
Hereinafter, the present invention will be described more specifically with reference to examples.
Polymerization of the polylactic acid polymer was performed by the following method.
After adding 300 parts of L-lactide to the flask and substituting the system with nitrogen, 0.4 part of stearyl alcohol and 0.02 part of tin octylate as a catalyst were added, polymerized at 190 ° C. for 2 hours, and finally reduced in pressure. And the monomer was removed to obtain L-polylactic acid. Next, after adding 300 parts of D-lactide to the flask and replacing the system with nitrogen, 0.59 parts of stearyl alcohol and 0.02 part of tin octylate as a catalyst were added, and polymerization was carried out at 190 ° C. for 2 hours. D-polylactic acid was obtained by subjecting to a reduced pressure treatment.

[Example 1]
After blending 50 parts by weight of L-polylactic acid prepared from a raw material containing 90 mol% L-lactide and 50 parts by weight of D-polylactic acid prepared from a raw material containing 90 mol% D-lactide, phosphoric acid Adeka stub NA-11 which is an ester metal salt was added so as to be 0.05 parts by weight, and melt-extruded with a kneading type extruder to obtain a pellet-shaped molded product.
This polymer was melt-spun at 240 ° C. using a die having 24 perforations, and wound at 4500 m / min. The resulting yarn had an elongation of 60% (89 dtex) and was used as a core yarn. Further, the same polymer was melt-spun at 240 ° C. using a die having 36 perforations, and wound at 2500 m / min, and the resulting yarn had an elongation of 114% (170 dtex) and was used as a sheath yarn.
These two types of yarns were aligned and entangled and drawn false twisted by the false twisting apparatus shown in FIG.
That is, the two yarns are supplied to the feed roller 6 and are interlaced with the first delivery roller 8 by the interlace nozzle 7 at an overfeed rate of 1.0% and a pneumatic pressure of 4 kg / cm ² , and are 36 pieces / m. Confounding is applied, and subsequently supplied to the false twisting zone via the roller 8, the draw ratio is 1.28 times, the false twist number is 2400 T / m, the heater temperature is 190 ° C., the yarn speed, that is, the speed of the second delivery roller 11 is 250 m / Stretch false twisting in min.
When the processed yarn obtained in this way is observed with a microscope, it is a uniform alternately twisted two-layer structure yarn, and a yarn constituting the core portion (elongation 28%) and a sheath portion (elongation 51%). A processed yarn having a partial entanglement (21 pieces / M) in which filaments enter each other between the strips. There was no processing yarn breakage while 30 kg of yarn was processed continuously by this false twisting. Moreover, when weaving using this yarn, there was no trouble such as the occurrence of neps in the weaving process, and the resulting fabric had a spun-like texture.

[Examples 2 to 7]
The raw yarns and processing conditions used in Examples 2 to 3 are the methods described in Table 1, and in Examples 4 to 7, one of the raw yarns is spun from polyethylene terephthalate pellets by the method described in Table 1. The obtained yarn was used, and the processing conditions were the same as those in Example 1 except that the processing conditions were as described in Table 1. In all of the obtained yarns, the processed yarn, the nep and the woven fabric had a spun-like texture.

[Comparative Example 1]
The same procedure as in Example 5 was carried out except that the phosphoric acid ester metal salt was not used at the stage of polymer preparation. However, since the tension variation in the false twisting process was large, it was not possible to obtain false twisted yarns. A false twisted yarn was obtained by the method described. However, even with this method, it was not possible to perform false twist processing stably and continuously.

[Comparative Example 2]
The spinning speed of the sheath yarn was 3000 m / min, and the others were carried out by the method described in Table 1. However, the false twisted yarn did not have a two-layer structure, and the produced fabric did not have a spun-like texture. It was. This is presumably because the difference in elongation of the filament yarn is 30%.

  The spun-like polylactic acid false twisted yarn of the present invention is a false twisted two-layer structure yarn (composite braided yarn) that is composed of an environment-friendly non-petroleum-derived polymer and has a spun-like appearance and texture, and is useful for clothing. is there.

1: Yarn with lower elongation 2: Yarn 3, 3 'with higher elongation 4: Raw yarn 4: Guide 5: Tension device 6: Feed roller 7: Interlace nozzle 8: First delivery roller 9: Heater 10: False twister 11: second delivery roller 12: winding roller 13: winding cheese

Claims (2)

A filament yarn having a low elongation constitutes a core portion, and a filament yarn having a higher elongation than the core portion filament yarn surrounds the core portion in an alternating twisted manner to form an outer layer portion, A spun-like polylactic acid, which is a two-layer false twisted yarn in which a part of both filament yarns are mixed and crossed at the boundary portion of the outer layer portion to form an entangled portion, and satisfies the following requirements False twisted yarn.
a) At least one of the filament yarns is a polylactic acid fiber.
b) The elongation of the filament yarn in the core portion is 25% or more, and the elongation of the filament yarn in the outer layer portion is 45% or more.
c) a polylactic acid fiber (i) a poly L-lactic acid (component A) having a weight average molecular weight of 100,000 to 200,000, (ii) a poly D-lactic acid (component B) having a weight average molecular weight of 100,000 to 200,000, and (iii) ) It consists of a composition containing 0.01 to 5 parts by weight of a phosphoric acid ester metal salt (C component) per 100 parts by weight of the total of component A and component B, and has a melting point of 200 ° C. or higher.   The process for producing a spun-like polylactic acid false-twisted yarn according to claim 1, wherein false twisting is performed with a difference in elongation of 40% or more between a filament yarn having a low elongation and a filament yarn having a high elongation.

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