JP2005187950A - Conjugated fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conjugated fiber consisting essentially of a biodegradable aliphatic polyester having excellent process passableness due to excellent dynamic characteristics possessed thereby and further excellent heat and abrasion resistances with excellent practicality when converted into a product. <P>SOLUTION: The conjugated fiber is a core-sheath conjugated fiber as follows. A thermoplastic resin forming a core part A is an aliphatic polyester and a thermoplastic resin forming a sheath part B is a crystalline polyester having ≥200°C melting point. The conjugated fiber is characterized in that the film thickness of the crystalline polyester forming the sheath part B is ≥0.4 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a composite fiber comprising an aliphatic polyester and a crystalline polyester having a melting point of 200 ° C. or more. More specifically, the present invention relates to applications requiring heat resistance and wear resistance, such as Y-shirts, blouses, and outerwear. The present invention relates to a core-sheath type composite fiber that can be suitably used as a clothing material.

  Recently, with increasing awareness of the environment on a global scale, the development of fiber materials that decompose in the natural environment is eagerly desired. For example, since conventional general-purpose plastics use petroleum resources as a main raw material, there are concerns that the petroleum resources will be depleted in the future, and global warming caused by mass consumption of petroleum resources has been taken up as major problems.

  For this reason, in recent years, research and development of various plastics and fibers such as aliphatic polyesters have been activated. Among them, attention is focused on plastics that are decomposed by microorganisms, that is, fibers using biodegradable plastics.

  Moreover, by using plant resources that grow by taking in carbon dioxide from the atmosphere, it can be expected that global warming can be suppressed by the circulation of carbon dioxide, and the problem of resource depletion may be solved. Therefore, attention has been focused on plastics starting from plant resources, that is, plastics using biomass.

  Until now, biodegradable plastics using biomass have not been used as general-purpose plastics due to their low mechanical properties and heat resistance, as well as high manufacturing costs. On the other hand, in recent years, polylactic acid using lactic acid obtained by fermentation of starch as a raw material has attracted attention as a biodegradable plastic having relatively high mechanical properties and heat resistance and low production cost.

  Polylactic acid has been used in the medical field for a long time as, for example, a surgical suture, but recently it has become competitive with other general-purpose plastics in terms of price due to improvements in mass production technology. For this reason, product development as a fiber has been activated.

  However, when polylactic acid is used as a general-purpose clothing fiber, it has several drawbacks compared to polyester and nylon fibers. Of these, it has been pointed out that heat resistance and wear resistance are low. In order to make up for these drawbacks, for example, it is conceivable to blend a plastic having excellent heat resistance and wear resistance such as nylon and polyester with polylactic acid. However, since these blended products cannot be uniformly blended, it has been difficult to stably fiberize them by melt spinning.

  In addition, some composite spinning with general-purpose plastics has been proposed as a method for improving the characteristics of polylactic acid fibers. For example, a composite fiber composed of a polyamide polymer and an aliphatic polyester has been proposed (Patent Document 1). However, the purpose of the composite fiber is to reduce the amount of the aliphatic polyester component by alkali to provide a new function, and therefore the aliphatic polyester component is exposed on the fiber surface. Therefore, it did not have heat resistance and wear resistance that can withstand practical use for clothing.

  Further, a composite fiber having an aromatic polyester as a core and an aliphatic polyester as a skin layer has been proposed (Patent Document 2). The composite fiber is subjected to surface modification by reducing the amount of the aliphatic polyester forming the skin layer with an enzyme, thereby enabling a good texture. However, it was found that the modification by enzyme treatment does not improve both heat resistance and wear resistance, but rather tends to deteriorate.

Further, a side-by-side type or eccentric core-sheath type composite fiber of a polytrimethylene terephthalate component and a polylactic acid component has been proposed (Patent Document 3). In the case of the eccentric core-sheath type composite fiber, the polylactic acid forming the core is coated with the high-melting point polytrimethylene terephthalate, so that it has better heat resistance than the conventional polylactic acid fiber. However, since the film is partially thin due to the eccentric structure, the film strength is weak and a product having sufficient heat resistance and wear resistance cannot be obtained.
JP 2000-54228 A (Claims) JP 2000-136439 A (Claims) JP 2003-82530 A (Claims)

  The present invention is intended to solve the above-mentioned conventional problems, and has excellent mechanical properties and excellent process passability, and when used as a product, has excellent heat resistance and wear resistance. It is intended to provide a composite fiber mainly composed of a biodegradable aliphatic polyester having the above.

  The above object is a core-sheath composite fiber in which the thermoplastic resin forming the core A is an aliphatic polyester, and the thermoplastic resin forming the sheath B is a crystalline polyester having a melting point of 200 ° C. or higher. This is achieved by a composite fiber characterized in that the film thickness of the crystalline polyester forming B is 0.4 μm or more.

  The present invention has excellent mechanical properties, heat resistance and abrasion resistance, and thus has excellent process passability in fabrics such as yarn making and yarn processing, warping and weaving, and also has excellent heat resistance as a product and It is possible to give wear resistance.

  The aliphatic polyester forming the core A of the conjugate fiber of the present invention refers to a thermoplastic polymer in which aliphatic alkyl chains are linked by ester bonds, such as polylactic acid, polyhydroxybutyrate, polybutylene succin. Nate, polyglycolic acid, polycaprolactone and the like. Among these, as described above, polylactic acid is preferable in terms of mechanical properties, heat resistance, and production cost.

Here, polylactic acid is a polymer having — (O—CHCH ₃ —CO) n— as a repeating unit, and is obtained by polymerizing lactic acid or its oligomer. Since lactic acid has two types of optical isomers, D-lactic acid and L-lactic acid, the polymer is poly (D-lactic acid) consisting only of D isomer and poly (L-lactic acid) consisting only of L isomer, and There is polylactic acid consisting of both. The optical purity of D-lactic acid or L-lactic acid in polylactic acid is lowered, the crystallinity is lowered, and the melting point drop is increased. Therefore, the optical purity is preferably 90% or more in order to improve heat resistance. A more preferable optical purity is 93% or more, and a still more preferable optical purity is 97% or more. As described above, the optical purity has a strong correlation with the melting point. The optical purity is about 90%, the melting point is about 150 ° C., the optical purity is 93%, the melting point is about 160 ° C., the optical purity is 97%, and the melting point is about 170 ° C. It becomes.

  In addition to the system in which two types of optical isomers are simply mixed as described above, the two types of optical isomers are blended and formed into a fiber, and then subjected to high-temperature heat treatment at 140 ° C. or higher. A stereo complex in which a racemic crystal is formed is more preferable because the melting point can be dramatically increased.

  In addition, residual monomers such as lactide are present in polylactic acid, but these low molecular weight residues can cause staining abnormalities such as heating heater stains in the drawing and false twisting processes and dyed spots in the dyeing process. It becomes. Further, in order to promote the hydrolyzability of the fiber and reduce the durability, these low molecular weight residues are preferably 1% by weight or less, more preferably 0.5% by weight or less, and further preferably 0.2% by weight or less. It is.

  In addition, components other than lactic acid may be copolymerized within a range that does not impair the properties of polylactic acid. However, from the viewpoint of biomass utilization and biodegradability, the lactic acid monomer ratio in the polylactic acid fiber needs to be 50% by weight or more. The lactic acid monomer is preferably 75% by weight or more, more preferably 96% by weight or more. Also, a thermoplastic polymer other than polylactic acid may be blended. Furthermore, additives such as particles, flame retardants, antistatic agents, antioxidants and ultraviolet absorbers may be contained as modifiers. Further, the molecular weight of the polylactic acid polymer is preferably 50,000 to 350,000 in terms of weight average molecular weight, and a good balance between mechanical properties and moldability is preferred, and more preferably 100,000 to 250,000.

  The method for producing the polylactic acid of the present invention is not particularly limited. Specifically, the method disclosed in JP-A-6-65360 is exemplified. That is, a direct dehydration condensation method in which lactic acid is dehydrated and condensed as it is in the presence of an organic solvent and a catalyst. Further, it is a method of copolymerizing and transesterifying at least two kinds of homopolymers disclosed in JP-A-7-173266 in the presence of a polymerization catalyst. Furthermore, there is a method disclosed in US Pat. No. 2,703,316. That is, an indirect polymerization method in which lactic acid is once dehydrated to form a cyclic dimer and then subjected to ring-opening polymerization.

  The thermoplastic resin forming the sheath B of the conjugate fiber of the present invention needs to be a crystalline polyester having a melting point of 200 ° C. or higher. By setting the melting point of the sheath part to 200 ° C. or more and the thickness of the sheath part described later to 0.4 μm or more, the heat resistance of the fiber can be drastically improved. The crystalline polyester is, for example, a polyester composed of a dicarboxylic acid component and a glycol component. As the dicarboxylic acid component, terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1 , 5-naphthalenedicarboxylic acid, 4,4′diphenyldicarboxylic acid, 4,4′diphenyl ether dicarboxylic acid, 4,4′diphenylsulfone dicarboxylic acid, 5-sodium sulfoisophthalic acid and other aromatic dicarboxylic acid components, succinic acid, Aliphatic dicarboxylic acid components such as adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, and eicosandioic acid can be used. These acid components can be used alone or in combination of two or more. Also good. Examples of the glycol component include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, , 6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2′bis (4′-β -Hydroxyethoxyphenyl) propane or the like can be used. These glycol components may be used alone or in combination of two or more. However, as described above, the melting point of the crystalline polyester is essential to be 200 ° C. or higher, and the melting point is preferably 205 to 260 ° C. in order to facilitate complex spinning with the core component. More preferably, it is 210-240 degreeC. In order to improve the heat resistance and the wear resistance, polyethylene terephthalate, polytrimethylene terephthalate and polybutylene terephthalate are preferably used among the crystalline polyesters, and polytrimethylene terephthalate is most preferably used. The crystalline polyester may be a homopolymer, a blend of the above polymers, or a copolymer, and further contains additives such as particles, flame retardants, antistatic agents, antioxidants and ultraviolet absorbers. Also good. The melting point of the crystalline polyester in the present invention is the peak temperature of crystal melting in DSC measurement, and at the same time, it is determined whether or not it is crystalline by the presence or absence of the crystal melting peak.

  Moreover, it is preferable that a compatibilizing agent is contained in the core component and / or the sheath component in order to enhance the adhesiveness of the composite interface between the core portion and the sheath portion and suppress interfacial peeling. As the compatibilizing agent, a compound that is compatible with both the core component and the sheath component, or a compound that reacts with the ends of both the core and sheath components to form a crosslinked structure is preferably used. It is not a thing. For example, the former compatibilizer includes a surfactant copolymer having a portion similar in basic structure to the core / sheath components, a block copolymer, and the like. Moreover, as what forms a crosslinked structure, the epoxy compound which has an epoxy group in the both terminal, an oxazoline compound, an oxazine compound, those copolymers, a carbodiimide compound, those copolymers, etc. are mentioned. When using a cross-linking agent, the cross-linking agent is added to one or both of the core / sheath components, and the cross-linking agent reacts with the terminal groups of each component existing in the vicinity of the composite interface, thereby interfacial adhesion. Will improve. Further, when polylactic acid is used as the core component, the reaction active terminal of the oligomer is blocked, so that the reaction active terminal in the polylactic acid is inactivated, and hydrolysis of polylactic acid can be suppressed. The reaction active terminal has a hydroxyl group and a carboxyl group, and examples of compounds having excellent carboxyl group blocking properties include the following compounds. As an epoxy compound preferably used as the carboxyl group blocking agent of the present invention, a glycidyl ether compound, a glycidyl ester compound, a glycidyl amine compound, a glycidyl imide compound, and an alicyclic epoxy compound can be preferably used.

  Examples of glycidyl ether compounds include butyl glycidyl ether, stearyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, o-phenylphenyl glycidyl ether, ethylene oxide lauryl alcohol glycidyl ether, ethylene oxide phenol glycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol Diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane trig Bisphenols such as sidyl ether, pentaerythritol polyglycidyl ether, 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) sulfone; Examples thereof include a bisphenol A diglycidyl ether type epoxy resin, a bisphenol F diglycidyl ether type epoxy resin, a bisphenol S diglycidyl ether type epoxy resin obtained from a condensation reaction with epichlorohydrin. Among these, bisphenol A diglycidyl ether type epoxy resin is preferable.

  Examples of glycidyl ester compounds include benzoic acid glycidyl ester, p-toluic acid glycidyl ester, cyclohexanecarboxylic acid glycidyl ester, stearic acid glycidyl ester, lauric acid glycidyl ester, palmitic acid glycidyl ester, versatic acid glycidyl ester, oleic acid glycidyl ester Ester, linoleic acid glycidyl ester, linolenic acid glycidyl ester, terephthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, phthalic acid diglycidyl ester, naphthalene dicarboxylic acid diglycidyl ester, bibenzoic acid diglycidyl ester, methyl terephthalic acid diglycidyl ester , Hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, Hexane dicarboxylic acid diglycidyl ester, adipic acid diglycidyl ester, succinic acid diglycidyl ester, sebacic acid diglycidyl ester, dodecanedioic acid diglycidyl ester, octadecanedicarboxylic acid diglycidyl ester, trimellitic acid triglycidyl ester, pyromellitic acid tetra A glycidyl ester etc. can be mentioned. Among these, benzoic acid glycidyl ester and versatic acid glycidyl ester are preferable.

  Examples of glycidylamine compounds include tetraglycidylaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, diglycidylaniline, diglycidyltoluidine, tetraglycidylmetaxylenediamine, diglycidyltribromoaniline, tetra Examples thereof include glycidyl bisaminomethylcyclohexane, triglycidyl cyanurate, and triglycidyl isocyanurate.

  Examples of glycidylimide compounds include N-glycidylphthalimide, N-glycidyl-4-methylphthalimide, N-glycidyl-4,5-dimethylphthalimide, N-glycidyl-3-methylphthalimide, N-glycidyl-3,6- Dimethylphthalimide, N-glycidyl-4-ethoxyphthalimide, N-glycidyl-4-chlorophthalimide, N-glycidyl-4,5-dichlorophthalimide, N-glycidyl-3,4,5,6-tetrabromophthalimide, N -Glycidyl-4-n-butyl-5-bromophthalimide, N-glycidyl succinimide, N-glycidyl hexahydrophthalimide, N-glycidyl-1,2,3,6-tetrahydrophthalimide, N-glycidyl maleimide, N- Glycidyl-α, β-dimethyl Succinimide, N-glycidyl-α-ethylsuccinimide, N-glycidyl-α-propylsuccinimide, N-glycidylbenzamide, N-glycidyl-p-methylbenzamide, N-glycidylnaphthamide, N-glycidylsteramide, etc. be able to. Of these, N-glycidylphthalimide is preferable.

  Examples of alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene diepoxide, N-methyl-4, 5-epoxycyclohexane-1,2-dicarboxylic imide, N-ethyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-phenyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide N-naphthyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-tolyl-3-methyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, and the like.

  Further, as other epoxy compounds, epoxy-modified fatty acid glycerides such as epoxidized soybean oil, epoxidized linseed oil, and epoxidized whale oil, phenol novolac type epoxy resins, cresol nozolac type epoxy resins, and the like can be used.

  Examples of the oxazoline compound preferably used as the carboxyl group blocking agent of the present invention include 2-methoxy-2-oxazoline, 2-ethoxy-2-oxazoline, 2-propoxy-2-oxazoline, 2-butoxy-2-oxazoline, 2-pentyloxy-2-oxazoline, 2-hexyloxy-2-oxazoline, 2-heptyloxy-2-oxazoline, 2-octyloxy-2-oxazoline, 2-nonyloxy-2-oxazoline, 2-decyloxy-2- Oxazoline, 2-cyclopentyloxy-2-oxazoline, 2-cyclohexyloxy-2-oxazoline, 2-allyloxy-2-oxazoline, 2-methallyloxy-2-oxazoline, 2-crotyloxy-2-oxazoline, 2-phenoxy- 2-oxa Phosphorus, 2-cresyl-2-oxazoline, 2-o-ethylphenoxy-2-oxazoline, 2-o-propylphenoxy-2-oxazoline, 2-o-phenylphenoxy-2-oxazoline, 2-m-ethylphenoxy- 2-oxazoline, 2-m-propylphenoxy-2-oxazoline, 2-p-phenylphenoxy-2-oxazoline, 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-propyl-2-oxazoline, 2-butyl-2-oxazoline, 2-pentyl-2-oxazoline, 2-hexyl-2-oxazoline, 2-heptyl-2-oxazoline, 2-octyl-2-oxazoline, 2-nonyl-2-oxazoline, 2- Decyl-2-oxazoline, 2-cyclopentyl-2-oxazoline, 2-si Rohexyl-2-oxazoline, 2-allyl-2-oxazoline, 2-methallyl-2-oxazoline, 2-crotyl-2-oxazoline, 2-phenyl-2-oxazoline, 2-o-ethylphenyl-2-oxazoline, 2 -O-propylphenyl-2-oxazoline, 2-o-phenylphenyl-2-oxazoline, 2-m-ethylphenyl-2-oxazoline, 2-m-propylphenyl-2-oxazoline, 2-p-phenylphenyl- 2-oxazoline, 2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4,4'-dimethyl-2-oxazoline) 2,2'-bis (4-ethyl-2-oxazoline), 2,2'-bis (4,4'-diethyl-2-oxazoline), 2, 2'-bis (4-propyl-2-oxazoline), 2,2'-bis (4-butyl-2-oxazoline), 2,2'-bis (4-hexyl-2-oxazoline), 2,2 ' -Bis (4-phenyl-2-oxazoline), 2,2'-bis (4-cyclohexyl-2-oxazoline), 2,2'-bis (4-benzyl-2-oxazoline), 2,2'-p -Phenylenebis (2-oxazoline), 2,2'-m-phenylenebis (2-oxazoline), 2,2'-o-phenylenebis (2-oxazoline), 2,2'-p-phenylenebis (4 -Methyl-2-oxazoline), 2,2'-p-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4-methyl-2-oxazoline), 2 , 2'-m-phenyle Bis (4,4′-dimethyl-2-oxazoline), 2,2′-ethylenebis (2-oxazoline), 2,2′-tetramethylenebis (2-oxazoline), 2,2′-hexamethylenebis ( 2-oxazoline), 2,2'-octamethylene bis (2-oxazoline), 2,2'-decamethylene bis (2-oxazoline), 2,2'-ethylenebis (4-methyl-2-oxazoline), 2,2'-tetramethylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethanebis (2-oxazoline), 2,2'-cyclohexylenebis ( 2-oxazoline), 2,2'-diphenylenebis (2-oxazoline) and the like. Furthermore, the polyoxazoline compound etc. which contain the above-mentioned compound as a monomer unit can be mentioned.

  Examples of the oxazine compound that can be used in the carboxyl group blocking agent of the present invention include 2-methoxy-5,6-dihydro-4H-1,3-oxazine, 2-ethoxy-5,6-dihydro-4H-1. , 3-oxazine, 2-propoxy-5,6-dihydro-4H-1,3-oxazine, 2-butoxy-5,6-dihydro-4H-1,3-oxazine, 2-pentyloxy-5,6- Dihydro-4H-1,3-oxazine, 2-hexyloxy-5,6-dihydro-4H-1,3-oxazine, 2-heptyloxy-5,6-dihydro-4H-1,3-oxazine, 2- Octyloxy-5,6-dihydro-4H-1,3-oxazine, 2-nonyloxy-5,6-dihydro-4H-1,3-oxazine, 2-decyloxy-5,6-dihydro- H-1,3-oxazine, 2-cyclopentyloxy-5,6-dihydro-4H-1,3-oxazine, 2-cyclohexyloxy-5,6-dihydro-4H-1,3-oxazine, 2-allyloxy- 5,6-dihydro-4H-1,3-oxazine, 2-methallyloxy-5,6-dihydro-4H-1,3-oxazine, 2-crotyloxy-5,6-dihydro-4H-1,3- Oxazine and the like, and 2,2'-bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-methylenebis (5,6-dihydro-4H-1,3- Oxazine), 2,2'-ethylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-propylenebis (5,6-dihydro-4H-1,3-oxazine), 2 , 2'- Tylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-hexamethylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-p-phenylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-m-phenylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-naphthylenebis (5 6-dihydro-4H-1,3-oxazine), 2,2'-P, P'-diphenylenebis (5,6-dihydro-4H-1,3-oxazine) and the like. Furthermore, the polyoxazine compound etc. which contain an above-described compound as a monomer unit are mentioned.

  Among the oxazoline compounds and oxazine compounds, 2,2′-m-phenylenebis (2-oxazoline) and 2,2′-p-phenylenebis (2-oxazoline) are preferable.

  The carbodiimide compound preferably used as the compatibilizing agent of the present invention is a compound having at least one carbodiimide group represented by (—N═C═N—) in the molecule, for example, in the presence of a suitable catalyst. The organic isocyanate can be heated and produced by a decarboxylation reaction.

  Examples of carbodiimide compounds include diphenylcarbodiimide, di-cyclohexylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, diisopropylcarbodiimide, dioctyldecylcarbodiimide, di-o-toluylcarbodiimide, di-p-toluylcarbodiimide, di-p- Nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p-hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di-2 , 5-dichlorophenylcarbodiimide, p-phenylene-bis-o-toluylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene- Su-di-p-chlorophenylcarbodiimide, 2,6,2 ', 6'-tetraisopropyldiphenylcarbodiimide, hexamethylene-bis-cyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, ethylene-bis-dicyclohexylcarbodiimide, N , N′-di-o-triylcarbodiimide, N, N′-diphenylcarbodiimide, N, N′-dioctyldecylcarbodiimide, N, N′-di-2,6-dimethylphenylcarbodiimide, N-triyl-N ′ -Cyclohexylcarbodiimide, N, N'-di-2,6-diisopropylphenylcarbodiimide, N, N'-di-2,6-di-tert-butylphenylcarbodiimide, N-toluyl-N'-phenylcarbodiimide, N, N'-di-p-nitrophenyl Carbodiimide, N, N′-di-p-aminophenylcarbodiimide, N, N′-di-p-hydroxyphenylcarbodiimide, N, N′-di-cyclohexylcarbodiimide, N, N′-di-p-toluylcarbodiimide, N, N'-benzylcarbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N-octadecyl-N'-tolylcarbodiimide, N-cyclohexyl-N'-tolylcarbodiimide, N- Phenyl-N'-tolylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, N, N'-di-o-ethylphenylcarbodiimide, N, N'-di-p-ethylphenylcarbodiimide, N, N'-di -O-isopropylphenylcarbodiimide, N, N'-di p-isopropylphenylcarbodiimide, N, N'-di-o-isobutylphenylcarbodiimide, N, N'-di-p-isobutylphenylcarbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N, N '-Di-2-ethyl-6-isopropylphenylcarbodiimide, N, N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N, N'-di-2,4,6-trimethylphenylcarbodiimide, N, Mono- or dicarbodiimide compounds such as N'-di-2,4,6-triisopropylphenylcarbodiimide, N, N'-di-2,4,6-triisobutylphenylcarbodiimide, poly (1,6-hexamethylenecarbodiimide) ), Poly (4,4'-methylenebiscyclohexylcarbodiimide), Poly (1,3-cyclohexylenecarbodiimide), poly (1,4-cyclohexylenecarbodiimide), poly (4,4'-diphenylmethanecarbodiimide), poly (3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide) , Poly (naphthylene carbodiimide), poly (p-phenylene carbodiimide), poly (m-phenylene carbodiimide), poly (tolyl carbodiimide), poly (diisopropylcarbodiimide), poly (methyl-diisopropylphenylene carbodiimide), poly (triethylphenylene carbodiimide) ) And polycarbodiimides such as poly (triisopropylphenylenecarbodiimide). Among these, N, N′-di-2,6-diisopropylphenylcarbodiimide and 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide are preferable, and polycarbodiimide is preferable.

  As the carboxyl group blocking agent, one or more compounds can be arbitrarily selected and used.

  When a carboxyl group blocking agent is added, it is important to determine the carboxyl group terminal amount of the component to be added. Furthermore, since residual oligomers such as lactide also generate carboxyl group terminals by hydrolysis, the total carboxyl terminal amount including not only the carboxyl group terminals of the polymer but also those derived from the remaining oligomers and monomers is important. For example, when polycarbodiimide is used as a crosslinking agent, free polycarbodiimide compounds can be reduced by adding 1.1 to 3 times the total amount of carboxyl end as the carbodiimide group equivalent of polycarbodiimide. Further, the interfacial adhesion can be remarkably improved by the crosslinked structure formed by blocking the carboxyl group ends of both the core and sheath components. The addition amount of the polycarbodiimide compound is more preferably 1.2 to 2.5 times equivalent to the total carboxyl terminal amount, and still more preferably 1.3 to 2.0 times equivalent.

  Further, the total carboxyl terminal concentration of the composite fiber is 20 equivalents / ton or less with respect to the whole fiber, and the hydrolysis resistance can be remarkably improved, and more preferably 10 equivalents / ton or less.

  Furthermore, a lubricant may be added to the crystalline polyester component in order to increase the lubricity in contact with the outside and improve the wear resistance. Lubricants include hydrocarbon waxes such as liquid paraffin, paraffin wax, micro wax and polyethylene wax, fatty acids such as stearic acid, 12-hydroxystearic acid and stearyl alcohol, higher alcohol waxes, stearamide and oleic acid. Amide lubricants such as amides, erucic acid amides, methylene bis stearic acid amides, ethylene bis stearic acid amides, ethylene bis oleic acid amides, ester waxes such as butyl stearate and monoglycerides of stearic acid, pentaerythritol tetrastearate, calcium stearate Metal soap such as zinc stearate, magnesium stearate or lead stearate can be applied. Of these, amide-based lubricants having a melting point of 100 ° C. or higher and excellent in external lubricity are preferred, and among them, fatty acid bisamides and alkyl-substituted fatty acid monoamides are most preferred. A plurality of these lubricants may be contained. The addition amount of the lubricant to the crystalline polyester is in the range of 0.05 to 5% by weight with respect to the crystalline polyester, and may be added in any of the polymerization step, drying, spinning step and the like.

  In the conjugate fiber of the present invention, it is important that the aliphatic polyester as the main component forms the core part A and is covered with the crystalline polyester as the sheath part B around the core part A. Moreover, high heat resistance is acquired because the film thickness formed with crystalline polyester is 0.4 micrometer or more. There is a clear correlation between the film thickness of the crystalline polyester and the heat resistance, and the heat resistance improves as the film becomes thicker. Therefore, the film thickness of the crystalline polyester is preferably 0.6 μm or more, and more preferably 0.8 μm or more. On the other hand, the upper limit of the film thickness is not particularly limited, but is preferably 10 μm or less in view of not impairing the characteristics of the aliphatic polyester. Further, the cross-sectional shape of the composite fiber may be any of a round cross-section, a polygon cross-section, a multi-leaf cross-section, a hollow cross-section, and other known cross-sections as long as it has a film thickness of 0.4 μm or more. In addition to a single core, a multi-core structure such as a 2-core or 3-core may be used. Examples of preferred cross-sectional shapes of the present invention are shown in FIGS. The coating thickness can be arbitrarily determined by the core-sheath composite ratio of the core part A and the sheath part B, the composite form, the discharge amount, the spinning speed, and the draw ratio, which are factors determining the fineness of the single fiber. it can.

  The fiber is subjected to external force in all processes such as a spinning process, a yarn processing process such as false twisting and fluid processing, and a weaving process such as beaming, weaving, and knitting. In order to suppress the peeling of the core-sheath composite interface and the occurrence of fluff caused thereby, a spinning oil mainly composed of a smoothing agent such as a fatty acid ester, mineral oil or polyether ester having a low friction coefficient is preferably used. By doing so, the process passage property in the said process can be improved significantly. The adhering amount of the spinning oil may be appropriately changed depending on the processing method and application, but it is preferably about 0.2 to 2% of the adhering amount with respect to the total weight of the fiber.

  Further, the mechanical properties of the composite fiber of the present invention may be at a level that does not cause a problem in practice. For example, when used for a textile for clothing, the strength is 2 cN / dtex or more, preferably 3 cN / dtex or more, and an elongation of 15 to It may be 60%, preferably 20 to 50%, initial tensile resistance of 40 cN / dtex or more, and boiling water shrinkage of 2 to 25%.

  In addition, the composite fiber of the present invention exhibits excellent performance with respect to high-temperature mechanical properties that are a problem with polylactic acid fibers. Usually, in the gluing drying performed after warping, drying is performed at a high temperature of about 80 ° C. while applying tension. At this time, the polylactic acid fiber has a problem that the tensile resistance at high temperature is small and the yarn extends. Since the conjugate fiber of the present invention is coated with crystalline polyester having excellent high-temperature mechanical properties, it is excellent in strength properties even under heating. The strength under heating at 90 ° C. is preferably 0.8 cN / dtex or more, and more preferably 1 cN / dtex. By the way, the strength of the fiber using 100% polylactic acid when heated at 90 ° C. is 0.3 cN / dtex at most.

  Moreover, it is preferable that the composite fiber of this invention is 2% or less in Wooster spots U% which is a parameter | index of the thickness spot of a fiber longitudinal direction. As a result, not only dyed spots on the fabric can be avoided, but also the shrinkage spots of the yarn when made into a fabric are suppressed, and a beautiful fabric surface is obtained. The Worcester plaque U% is more preferably 1.5% or less, further preferably 1% or less, and most preferably 0.6% or less.

  The form of the fiber is not particularly limited, such as long fiber or short fiber. In the case of long fiber, it may be multifilament or monofilament.

  Moreover, the form of the fiber structure of the present invention is not limited to woven fabrics, knitted fabrics, non-woven fabrics for clothing such as shirts, blousons, pants, etc., alone or mixed with other fibers, cups, pads, boards, etc. Various textile products such as clothing materials, interiors such as curtains, carpets, mats, furniture, vehicle interiors, belts, nets, ropes, heavy cloth, bags, sewing threads, felts, non-woven fabrics, filters, artificial turf, etc. Including the form. When mixed with other fibers, synthetic fibers made of fiber-forming polymers such as polyester fibers, nylon fibers, acrylic fibers, vinylon fibers, polypropylene fibers, polyethylene fibers, regenerated fibers such as rayon, semi-synthetic materials such as acetate Fibers and natural fibers such as wool, silk, cotton and hemp are used. However, in order to make use of the characteristics of the aliphatic polyester, the content ratio of the present composite fiber is preferably 20% or more, and more preferably 50% or more.

  Moreover, the textile structure of this invention is used suitably for the textiles for clothes, the use which receives an iron press among them. The heat resistance of the fiber structure composed of the conjugate fiber of the present invention is preferably 160 ° C. or higher in the iron heat resistance test. By having a heat resistance of 160 ° C. or higher, it is possible to obtain a fiber structure that does not have a texture hardening or change in color tone even when ironing at low to medium temperatures. Here, the iron heat resistance test method will be described in detail.

For measurement, a commercially available iron is used, the iron surface temperature is stabilized to a desired temperature, and then the fabric is pressed for 10 seconds with the iron's own weight (surface pressure of about 8 g / cm ² ). . As a result of conducting an iron heat resistance test on a fabric composed of 100% polylactic acid fiber by the present inventors, the heat resistance of the polylactic acid fabric is at most about 120 ° C., and beyond that, the fiber is softened and flattened. A glossy spot called “around” occurs. Further, when the temperature of the iron is set to 150 ° C., a hole is formed due to partial melting, or a cloth with a strong feeling of coarseness is obtained, which is no longer practical. For this reason, it was impossible to apply a substantial iron when using 100% polylactic acid fiber. On the other hand, the woven fabric made of the conjugate fiber of the present invention has a heat resistance of 160 ° C. or higher, and the softening and deformation of the fiber does not occur in a low to medium temperature iron, and there are no defects such as “around”. is there.

  Moreover, when using the fiber structure which consists of the composite fiber of this invention irrespective of the object for clothing and industrial materials, it is requested | required that a practical level should be satisfy | filled in the various dyeing fastness tests determined by JIS. For example, when used for general apparel, a third or higher grade is required in terms of dyeing fastness to washing (JIS-L0844, 1998) and dyeing fastness to ultraviolet carbon arc lamps (JIS-L0842, 1998).

  As for the wear resistance which is the object of the present invention, it is preferable that both dryness and wetness are grade 3 or higher in the friction tester type II (Gakushin type) of the dyeing fastness test for friction (JIS-L0849). It is more preferable that both the dryness and the wetness are quaternary or higher. In addition, when the dyeing fastness test is carried out on a fabric made of 100% polylactic acid, the dyeing fastness to rubbing against the friction is very bad at the first grade for both dryness and wetness, although it passes the third grade in the washing and light resistance test.

  Here, the manufacturing method of the composite fiber of this invention is demonstrated with figures.

  First, an aliphatic polyester that forms the core A and a crystalline polyester that forms the sheath B are selected from the polymers described above. For example, poly L lactic acid (melting point: 170 ° C.) having a weight average molecular weight of 100,000 to 200,000 and an optical purity of 97% is used for the core A, and polytrimethylene terephthalate (melting point 228 ° C.) is used for the sheath B. FIG. 3 is a schematic view of a spinning apparatus preferably used in the present invention. First, a polylactic acid chip charged in a hopper 1 is melted and extruded by an extruder 2 and the molten polymer is transferred to a spinning block 4. Similarly, the polytrimethylene terephthalate chip charged in the hopper 1 ′ is melted and extruded by the extruder 2 ′, and the molten polymer is phased on the spinning block 4. Further, the yarn is sent to a spinning pack 5 incorporated in the spinning block 4, and after filtering the polymer in the pack, the polymer is bonded to the core-sheath structure by the spinneret 6 and then discharged to obtain a yarn. The spun yarn is once cooled and solidified by the cooling device 7, and then an oil agent is applied by the oil supply guide 9, and is appropriately entangled by the entanglement device 10, then taken up by the godet rolls 11 and 12, and wound. It is wound up by the take-up machine 13. In addition, in order to remove the low melting point substance sublimated from the fiber, a suction device 8 is provided directly under the base. In addition, in order to suppress the precipitation of monomers and oligomers during spinning and to improve the spinnability, a 2-20 cm heating cylinder under the die, air for preventing polymer oxidation deterioration or die hole contamination, steam, N2 as necessary. Inert gas generators such as may be installed. The temperature of the spinning block is determined by the melting point of each of the core-sheath components on the high melting point side. When polytrimethylene terephthalate or polybutylene terephthalate is used on the high melting point side, melt spinning may be performed at 240 to 255 ° C. Next, the film is stretched by a stretching machine or stretched and false twisted by a false twisting machine. A spin draw method in which spinning and stretching are continuously performed is also preferably used.

  When melt spinning, if the residence time during kneading and melt spinning is long, there is a problem that the polymer is colored due to thermal deterioration of the raw material polymer and the compatibilizing agent. Therefore, the shorter the residence time, the better, and preferably 30 minutes or less. In addition, the temperature of the molten polymer at this time is preferably as low as possible while ensuring fluidity. The residence time refers to the residence time from the melting of the polymer to the spinning, which includes the gap between the barrel and screw of the kneader, the specifications of the screw, the piping size between the kneader and the spin pack, the spin pack. It can be estimated from the dimensions inside. The residence time is more preferably 20 minutes or less, and even more preferably 15 minutes or less. Similarly, it is preferable to devise a method for adding a compatibilizing agent. The compatibilizing agent may be kneaded with the raw material polymer in advance, but it is preferable to add the compatibilizing agent directly during melt spinning in order to suppress the residence time. For example, when polylactic acid is melted in a kneader, the residence time in the melted state of the compatibilizer can be shortened by adding the compatibilizer while measuring with a side feeder or the like.

  The spinning oil may be appropriately selected depending on the higher order process. When it is used for weaving and knitting after stretching, the fiber-metal friction coefficient is effectively reduced in order to suppress the abrasion between the fiber and the yarn guide, the knitting needle, etc. as much as possible. It is preferable to use an oil containing a high smoothing agent. For example, fatty acid ester, polyhydric alcohol ester, ether ester, silicone, mineral oil and the like are preferable. These smoothing agents may be used as a single component, but a plurality of components may be mixed and used in consideration of convergence, antistatic properties, and heat resistance. As more preferred smoothing agents, fatty acid esters and mineral oils can be selected. The fatty acid ester is not particularly limited, and examples thereof include monohydric alcohols and monohydric carboxylic acids such as methyl oleate, isopropyl myristate, octyl palmitate, oleyl laurate, oleyl oleate, and isotridecyl stearate. Monohydric alcohols such as esters, dioctyl sebacate, dioleyl adipate, and esters of polyvalent carboxylic acids, polyhydric alcohols such as ethylene glycoldiolate, trimethylolpropane tricaprylate, glycerol trioleate, and monovalents Examples thereof include esters of carboxylic acids and alkylene oxide addition esters such as lauryl (EO) n octanoate. The content of these smoothing agents is adjusted to 55 to 95% by weight based on the whole oil agent, and other components include ionic surfactants, nonionic surfactants, bundling agents, rust preventives, preservatives, and antioxidants. An agent, a penetrating agent, a surface tension reducing agent, a phase inversion viscosity reducing agent, an adhesive property improving agent, an antistatic agent, a pH lowering inhibitor, and a water resistance agent may be added as appropriate.

  When supplying to a stretched false twist, prevent false twisting of the false twisting heater, prevent slippage with the twisted body (improve threading, improve the number of twists on the false twisting heater), and improve fiber migration within the multifilament. This is very important. For this purpose, it is preferable to use an oil containing a smoothing agent having good heat resistance, a high fiber-twisted friction coefficient, and a low fiber-fiber friction coefficient. For example, a compound obtained by copolymerizing an alkylene oxide having 2 to 4 carbon atoms with an alcohol having one or more hydroxyl groups in the molecule and a compound derived therefrom are preferably used.

  As the alcohol, any natural or synthetic monohydric alcohol having 1 to 30 carbon atoms (methanol, ethanol, isopropanol, butanol, isoamyl alcohol, 2-ethylhexanol, lauryl alcohol, isotridecyl alcohol, isocetyl alcohol, stearyl alcohol) , Isostearyl alcohol, etc.), dihydric alcohols (ethylene glycol, propylene glycol, neopentyl glycol, hexylene glycol, etc.) and trihydric or higher alcohols (glycerin, trimethylolpropane, pentaerythritol, sorbitan, sorbitol, etc.). .

  The alkylene oxide having 2 to 4 carbon atoms includes ethylene oxide (hereinafter abbreviated as EO), 1,2-propylene oxide (hereinafter abbreviated as PO), 1,2-butylene oxide (hereinafter abbreviated as BO), tetrahydrofuran (hereinafter referred to as THF). Abbreviations). When EO is copolymerized with other alkylene oxide, the ratio of EO needs to be 50 to 80% by weight. If the EO ratio is less than 50% by weight, the viscosity becomes too high, and if it exceeds 80% by weight, the heat resistance becomes poor. The addition mode may be either random addition or block addition. The average molecular weight of the smoothing agent is preferably in the range of 500 to 20,000, more preferably in the range of 1,000 to 10,000 in terms of smoothness and heat resistance.

  The content of these smoothing agents is adjusted to 55% by weight or more based on the whole oil agent, and as other components, ionic surfactants, nonionic surfactants, bundling agents, rust preventives, antiseptics, antioxidants A paste property improver, an antistatic agent, a pH lowering inhibitor, and a water resistance agent may be added as appropriate.

  Moreover, it is preferable that the spinning oil agent is adhered to 0.1 to 3.0% by weight with respect to the whole fiber. The said characteristic is exhibited effectively by making the adhesion amount of an oil agent into 0.1 weight%. On the other hand, when the amount of the oil agent to be adhered exceeds 3% by weight, the false twisting heater, the roll, and the twisted body become very dirty. More preferably, it is 0.2-2.0 weight%, More preferably, it is 0.3-1.0 weight%.

  The oil agent preferably used in the present invention may be adhered straight to the yarn, but in order to adhere more uniformly, it is dispersed as 5 to 50% by weight in water, preferably 5 to 30% by weight, and the fiber is used as an emulsion oil agent. It is preferable to make it adhere to.

  The entanglement nozzle 11 may be installed on the spinning line as shown in FIG. 1, or may be installed between the godet rolls or before the winder. When it is desired to increase the degree of entanglement, it is preferably installed between godet rolls with low yarn tension or before the winder, and when it is desired to reduce the degree of entanglement, it is preferably installed on the spinning line.

  Moreover, in order to improve the adhesiveness of the core-sheath composite interface, the spinning speed (the peripheral speed of the first godet roll 12 in FIG. 3) is an important condition. The aliphatic polyester constituting the core part and the crystalline polyester constituting the sheath part have relatively good affinity, and the interfacial adhesion can be further improved by adding a compatibilizing agent. Furthermore, it has been found by the inventors' study that the adhesiveness is improved by increasing the spinning speed. Although this mechanism is not yet clear, thinning of the spun yarn occurs in a high-temperature region closer to the die surface by high-speed spinning, so that the difference in structural strain between the core-sheath components becomes smaller, and further, the stretch orientation This is considered to form a more stable fiber internal structure. Therefore, a preferable spinning speed is 2000 m / min or more, more preferably 2500 m / min or more, and still more preferably 3000 m / min or more. On the other hand, considering the process stability in spinning, the spinning speed is preferably 7000 m / min or less.

  The multifilament made of the composite fiber of the present invention, when polytrimethylene terephthalate is used for the sheath part B, relaxes (shrinks) the internal strain of the fiber, so when wound on a cheese-like package, a saddle (earing) And bulges are likely to occur. When the saddle or bulge is large, not only the packaging of the package becomes complicated, but also the unraveling property is lowered and the process passability is lowered. Therefore, it is preferable to suppress the saddle to 6 mm or less and the bulge rate to 10% or less. More preferably, the saddle is 0 to 4 mm and the bulge rate is 0 to 6%.

  In order to eliminate saddles and bulges, it is necessary to remove the internal strain of the fiber between melt spinning and winding, and as a method for this, winding in a relaxed state is effective. Further, the winding tension at that time (the tension between the final godet roll and the winder) is preferably 0.04 cN / dtex or more in order to prevent reverse winding, and the distortion of the fiber internal structure is released. Therefore, it is preferable to make it 0.15 cN / dtex or less. A more preferable winding tension is 0.05 to 0.12 cN / dtex, and further preferably 0.06 to 0.1 cN / dtex. Moreover, it is preferable to make the load with respect to the line length which a roller bail or a drive roll is contacting the package (equivalent to the pressure with respect to a package. Hereinafter, it is called a surface pressure) into the range of 6-16 kg / m. By setting the surface pressure to 6 kg / m or more, an appropriate hardness can be given to the package, and package collapse and saddle can be suppressed. Further, by making the surface pressure 16 kg / m or less, the package can be prevented from being crushed or bulged. A more preferable range is 8 to 12 kg / m. In addition, by setting the twill angle in the range of 5 to 10 °, it is possible to obtain a stable unwinding tension even at high speed unwinding and to prevent the yarn from collapsing to the end surface while suppressing the yarn dropping on the package end surface. Can do. More preferably, it is 5.5 to 8 °, and further preferably 5.8 to 7 °. It is also important to change the twill angle to suppress the ribbon. As a means for this, it is preferable that the traverse angle is oscillated within a certain range (within the center value ± 1.5 °) or the wind ratio (ratio between the spindle rotation speed and the traverse cycle) is made constant. Further, a method of rapidly changing the twill angle in the ribbon generation zone region is also preferably used, and these methods may be combined. In general, since aliphatic polyester has low bending rigidity and strong behavior as an elastic body, it is necessary to devise a way to sufficiently follow the yarn when turning back during traverse. For this reason, a 1- to 3-axis blade traverse method with high-speed followability, a microcam traverse with good thread gripping properties, and a spindle traverse capable of shortening the free length are preferably used. Taking advantage of each characteristic, it is more preferable to use the microcam traverse method at a winding speed of 2000 to 4000 m / min, and to use a 1-axis to 3-axis blade traverse system when the winding speed exceeds 4000 m / min.

  The drive system at the time of winding is generally driven by a drive roller, but a spindle driving system and a method of forcibly driving a roller bail of the winder are preferably used. When the roller bail is forcibly driven, the roll bail speed relative to the package surface speed is controlled to always overfeed by 0.05 to 1%, and relaxing winding can further improve the package foam. .

  Moreover, the temperature at the time of extending | stretching the obtained undrawn yarn package should just be able to be made stably without a yarn spot, for example, when a core component is polylactic acid, it is 80-150 degreeC, More preferably, it is 90-120 degreeC. The heat setting temperature may be changed as appropriate in order to obtain a desired heat shrinkage rate. The high shrinkage yarn type is 20 to 90 ° C., the middle shrinkage type is 90 to 120 ° C., the low shrinkage type is 120 to (melting point of the core component− 15) What is necessary is just to implement at degreeC. As described above, in order to increase the melting point by making the core A into a stereo complex, the higher the heat setting temperature, the better, and the range of 140 to 200 ° C. is preferable.

  In addition, when false twisting is performed, a contact-type hot plate may be used at a melting point of the core component of −70 to −15 ° C., while increasing the CR value, which is an index of crimp characteristics, and improving process stability. In order to increase the melting point, the melting point of the core component is −60 to −20 ° C., more preferably −50 to −25 ° C. When a non-contact type heater is used, yarn breakage due to rubbing is suppressed, so that treatment at a higher temperature is possible, which is preferable.

Hereinafter, the present invention will be described in detail with reference to examples. In addition, the measuring method in an Example used the following method.
A. Weight average molecular weight of aliphatic polyester Tetrahydrofuran was mixed with the sample chloroform solution to prepare a measurement solution. This was measured by gel permeation chromatography (GPC), and the weight average molecular weight was determined in terms of polystyrene.
B. Intrinsic viscosity [η]
A sample polymer was dissolved in orthochlorophenol (hereinafter abbreviated as OCP), and a relative viscosity ηr at a plurality of points was determined using an Ostwald viscometer at a temperature of 25 ° C., and the outer layer was determined as an infinite dilution.
C. Melting | fusing point Melting | fusing point was measured by 2nd run using DSC-7 made from Perkin elmer. At this time, the sample weight was about 10 mg, and the heating rate was 10 ° C./min.
D. Total carboxyl terminal concentration A precisely weighed sample was dissolved in o-cresol (water content 5%), and an appropriate amount of dichloromethane was added to the solution, followed by titration with a 0.02 N KOH methanol solution. At this time, an oligomer such as lactide, which is a cyclic dimer of lactic acid, is hydrolyzed to generate a carboxyl group terminal, so that all of the carboxyl group terminal of the polymer, the monomer-derived carboxyl group terminal, and the oligomer-derived carboxyl group terminal are totaled. The carboxyl group terminal concentration obtained is obtained.
E. Residual lactide amount 1 g of a sample is dissolved in 20 ml of dichloromethane, and 5 ml of acetone is added to this solution. Furthermore, it was made to deposit with cyclohexane, it was made to precipitate, it analyzed by the liquid chromatograph using Shimadzu GC17A, and the lactide amount was calculated | required with the absolute calibration curve.
F. Crystalline polyester film thickness Fix the sample fiber with embedding material, cut out the slice, embed it, magnify it with an optical microscope, photograph it, and use the scale taken at the same magnification to make the sheath thickness Was measured. In addition, when the thickness of the sheath portion was uniform, the average of three values measured at equal intervals was used, and when it was not uniform, the thinnest portion was defined as the thickness of the film of the sample.
G. Strength and elongation Measured according to the chemical fiber filament yarn test method (1998) of JIS L1013. Note that a load-elongation curve was obtained with a gripping interval of 200 mm and a tensile speed of 200 mm / min. Next, the load value at the time of breaking was divided by the initial fineness, which was taken as the strength, the elongation at the time of breaking was divided by the initial sample length, and the strength and elongation were obtained as the elongation. In addition, the temperature at the time of measurement was carried out under two conditions of room temperature (25 ° C.) and high temperature (elongation in a 90 ° C. heating furnace), and the strength measured at room temperature was measured in a 90 ° C. heating furnace. The thing was described as 90 degreeC intensity | strength.
H. Boiling water shrinkage Boiling water shrinkage (%) = [(L0−L1) / L0)] × 100 (%)
L0: Raw length measured with a sample taken and measured under an initial load of 0.09 cN / dtex L1: A cassette with a measured L0 was treated in boiling water for 15 minutes in a load-free condition, air-dried overnight, and then the initial load was 0 Case length under 0.09 cN / dtex Yarn spots U%
Using UT4-CX / M manufactured by Zellweger uster, U% (Normal) was measured at a yarn speed of 200 m / min and a measurement time of 1 minute.
J. et al. CR value The crimped yarn was scraped, treated in boiling water for 15 minutes in a substantially load-free state, and air-dried for 24 hours. The sample was immersed in water under a load equivalent to 0.088 cN / dtex (0.1 gf / d), and the skein length L0 after 2 minutes was measured. Next, the skein length L1 after 2 minutes was measured after exchanging with a fine load equivalent to 0.0018 cN / dtex (2 mgf / d), except for the case corresponding to 0.088 cN / dtex in water. And CR value was calculated by the following formula.

CR (%) = [(L0−L1) / L0] × 100 (%)
K. Saddle and bulge ratio In a 5 kg wound package, the winding thickness L1 at the center of the undrawn yarn package and the winding thickness L2 at the end face were measured, and the value obtained by subtracting L1 from L2 was taken as the size of the saddle. Further, the winding width L3 of the innermost layer of the undrawn yarn package shown in FIG. 2 and L4 indicating the maximum winding width were measured, and the bulge rate was calculated by the following equation.

Bulge rate (%) = [(L4−L3) / L3] × 100
L. Iron heat resistance test A sample of approximately 84 dtex was woven as a warp and weft into a plain woven fabric at a weaving density of 110 × 90 pieces / 2.54 cm, set in a living machine with a 140 ° C. tenter, and then scoured to obtain a woven fabric. This fabric was dyed at 110 ° C. for 60 minutes with a disperse dye Dianix Black BG-FS200 1% owf concentration, then 80 ° C. at a concentration of 2 g / liter of Gran Up INA-5 (manufactured by Sanyo Chemical) and 0.5 g / liter of sodium carbonate. Soaped for 20 minutes and finished at 130 ° C.

About the obtained dyed cloth, using a steam iron A-1F manufactured by Sanyo Electric Co., Ltd., when the iron surface temperature reaches a predetermined temperature, the cloth is pressed with the iron's own weight (surface pressure of about 8 g / cm ² ) for 10 seconds. The appearance change after pressing was evaluated.

"No change" is "◎", "Slight attrition" is "○", "Clear attrition" is "△", "Partial fusion between fibers" is "X", "Melting" “Perforated” by “XX”.
M.M. Dyeing fastness test Dyeing cloths obtained in the same manner as in section L were subjected to class judgment according to dyeing fastness to washing JIS L0844 (1998) and dyeing fastness test to carbon arc lamp JIS L0842 (1998). .
N. Dye fastness test against friction A dyed fabric obtained in the same manner as in section L is treated using a friction tester type II (Gakushoku type) in accordance with JIS L0849 (1998). The grade was judged in 5 stages.

Example 1
A polycarbodiimide "carbodilite" HMV-8CA manufactured by Nisshinbo Co., Ltd. as a compatibilizer in poly L lactic acid (optical purity 97% L lactic acid) having a weight average molecular weight of 16,000, a melting point of 170 ° C. and a residual lactide amount of 0.085% by weight. 1% by weight of polytrimethylene terephthalate having an intrinsic viscosity [η] of 0.92 (melting point 228) containing 0.3% by weight of titanium oxide having an average secondary particle size of 0.4 μm. ° C) as a sheath part, each of which is melted separately using a spinning machine shown in FIG. 3 and has a structure shown in FIG. 4 at a spinning temperature of 250 ° C. (discharge hole diameter 0.25 mm / hole depth 0.75 mm) And was discharged at a core-sheath composite ratio (% by weight) of 70:30. The residence time from melting to discharging was about 12 minutes for the core component and about 16 minutes for the sheath component. The discharged yarn is cooled and solidified by a cooling chimney 9 with a cooling air of 0.5 m / sec, and an oil agent is applied while being focused by the oil supply device 10 at a position 2 m below the base. The cheese package was entangled at 0.2 MPa, taken up by the first godet rolls 12 and 13 at a peripheral speed of 3000 m / min, and wound with 5 kg of 110 dtex and 36 filaments of a core-sheath composite structure. The peripheral speed of the winder 14 was about 2940 m / min, and the peripheral speed was varied so that the winding tension was always 0.08 cN / dtex. The surface pressure during winding was 10 kg / m, and the twill angle was 6 °. In addition, the spinning oil contains 100% fatty acid ester as a smoothing agent, 20% mineral oil, and polyhydric alcohol ester, polyoxyethylene nonion and amide nonion to prevent adhesive adhesion and metal wear. The stock solution was diluted with pure water to give a 15% aqueous emulsion, and about 0.8% by weight was adhered to the fiber as pure oil. The spinnability was good, and no yarn breakage occurred when sampling 50 kg of undrawn yarn. Further, the saddle of the package was 4 mm, and the bulge was 5%, which was a good foam.

  Further, the unstretched yarn was stretched at a rate of 800 m / min, a stretching ratio of 1.3 times, a stretching temperature of 90 ° C., and a heat setting temperature by a 4-roll stretching machine (supply roll-heating roll-heating roll-room temperature roll-winding machine). Drawing was performed at 130 ° C. to obtain a drawn yarn of 84 dtex and 36 filaments. The drawability was good, and yarn breakage and wrapping to a hot roll did not occur. The cross-sectional shape of the obtained yarn was the circular shape shown in FIG. 1 (a), and the coating thickness of the sheath portion was 1.2 μm.

  The strength of Example 1 was 3.8 cN / dtex, the elongation was 35%, U% (normal test) was 0.6%, and the boiling water shrinkage was 10%. Furthermore, the iron heat resistance when it was made into a woven fabric did not change its surface even at 200 ° C. and showed extremely good heat resistance. Also, in the dyeing fastness test against friction, both dryness and wetness were grade 4.

  As described above, Example 1 shows the mechanical properties of the raw yarn and the heat resistance and wear resistance of the fabric, which are sufficiently practical, and can be suitably used for clothing applications.

Example 2 and Example 3
Evaluation was made in the same manner as in Example 1 except that the core-sheath composite ratio was 80/20 and 88/12. The film thickness of Example 2 having a sheath composite ratio of 20% is 0.8 μm, the iron heat resistance does not change up to 180 ° C., and the dyeing fastness to friction is sufficiently practical for dry grade 3 and wet grade 4 It showed the heat resistance and wear resistance that could be tolerated. The film thickness of Example 3 having a sheath composite ratio of 12% was 0.45 μm. The iron heat resistance did not change at 160 ° C., and a slight crack was observed even at 200 ° C. In addition, the dyeing fastness to friction is dry grade 3 and wet grade 4 and is lower than that of Example 1, but it is a level that can be developed for applications that do not require much wear resistance, such as inner and curtains. .

Comparative Example 1
Evaluation was made in the same manner as in Example 1 except that the core-sheath composite ratio was 92/8. The film thickness of Comparative Example 1 was 0.3 μm. Although the strength, yarn unevenness U%, etc. show good values, the iron heat resistance has some attrition at 160 ° C., and at 180 ° C., noticeable attrition occurs due to deformation of the fiber, resulting in a strong surface gloss appearance, The texture was rough. In addition, the fastness to dyeing with respect to friction was second grade for both dry and wet, and was impractical.

Comparative Example 2
Evaluation was made in the same manner as in Example 1 except that the core-sheath composite ratio was changed to 100/0 (poly L lactic acid alone). In Comparative Example 2, although the strength, yarn unevenness U%, and the like are good, in the iron heat resistance test, a partial fusion occurs at 160 ° C. to give a strong texture, and at 180 ° C. it melts and opens a hole. I have. Further, the fastness to dyeing with respect to friction was first grade for both dry and wet, and was impractical.

Example 4
Evaluation was performed in the same manner as in Example 1 except that polybutylene terephthalate (melting point 224 ° C.) having an intrinsic viscosity [η] of 0.88 was used for the sheath. In Example 4, both spinnability and drawability were good, and no yarn breakage occurred even with 50 kg of yarn. In addition, strength and yarn unevenness U% are good, iron heat resistance does not change up to 180 ° C, and dyeing fastness to friction is dry grade 3 and wet grade 4 and shows heat resistance and wear resistance that can withstand practical use. It was.

Example 5
Evaluation was performed in the same manner as in Example 1 except that copolymer PET (melting point: 230 ° C.) containing 9 mol% of IPA in the sheath was used. In Example 5, both spinnability and drawability were good, and no yarn breakage occurred even with 50 kg of yarn. In addition, the strength and the yarn unevenness U% were good, but the boiling water shrinkage was somewhat high. The iron heat resistance did not change up to 180 ° C., and the dyeing fastness to friction was dry grade 3 and wet grade 4;

Example 6
Evaluation was performed in the same manner as in Example 1 except that DuPont biodegradable polyester “Biomax” 4027 (melting point: 237 ° C.) was used for the sheath. In Example 6, both spinnability and drawability were good, and no yarn breakage occurred even with 50 kg of yarn. Further, the strength and the yarn unevenness U% were also good. The iron heat resistance did not change even at 200 ° C., and the dyeing fastness to friction was dry grade 3 and wet grade 4 and showed heat resistance and wear resistance that could withstand practical use.

Comparative Example 3
Evaluation was performed in the same manner as in Example 1 except that DuPont biodegradable polyester “Biomax” 4024 (melting point: 199 ° C.) was used for the sheath. In Comparative Example 3, both spinnability and stretchability were good, and no yarn breakage occurred even with 50 kg of yarn. Further, the strength and the yarn unevenness U% were also good. However, in the iron heat resistance test, the appearance became strong with surface gloss at 160 ° C., and the practicality was poor.

Example 7
The poly L lactic acid (optical purity 97% L lactic acid) having a weight average molecular weight of 16,000, a melting point of 170 ° C. and a residual lactide amount of 0.085 wt% used in Example 1, and a poly D lactic acid having a weight average molecular weight of 200,000 ( Chip blending with optical purity 97% D lactic acid, melting point 170 ° C. at a weight ratio of 1: 1, melt-kneading at 240 ° C. with a twin screw extrusion kneader, and then a static kneader (Toray Engineering) installed in the spinning machine It was evaluated in the same manner as in Example 1 except that it was led to a spinning pack after passing through “High Mixer” (10 stages) manufactured by the company and used as a core component (no compatibilizer added). In the sample of Example 7, the melting point of the double peak was detected by DSC. One is a peak near the melting point of 228 ° C., so that it is a melting peak of the PTT crystal, and the other is presumed to be a melting peak of a stereocomplex crystal of polylactic acid having a melting point of 220 ° C. In addition, although Example 7 was slightly lower in strength than Example 1, it exhibited excellent characteristics in both iron heat resistance and dyeing fastness to friction.

Example 8
Evaluation was made in the same manner as in Example 1 except that no compatibilizing agent was contained in the core component. In Example 8, some cracks occurred in the iron heat resistance test at 200 ° C. Further, although the abrasion resistance was slightly inferior to that of Example 1, it was at a level causing no practical problem.

Example 9
Polycarbodiimide "Carbodilite" manufactured by Nisshinbo Co., Ltd. as a compatibilizer in poly L lactic acid (optical purity 91% L lactic acid) having a weight average molecular weight of 16,000, melting point of 155 ° C and residual lactide amount of 0.15% by weight as the core component The same method evaluation as in Example 1 was performed except that 1% by weight of HMV-8CA was added and mixed to form core A. The sample of Example 9 had a slight attack in the iron heat resistance test at 160 ° C., but a clear attack occurred at 180 ° C. and 200 ° C., and ironing at a high temperature was impossible. It was. Further, the wear resistance was excellent as in Example 1.

Example 10
Evaluation was performed in the same manner as in Example 1 except that 1% by weight of ethylenebisstearic acid amide “Alflow” H-50T manufactured by Nippon Oil & Fats Co., Ltd. was added as a lubricant to the PTT of the sheath component. In the same manner as in Example 1, Example 10 showed extremely excellent heat resistance in the 200 ° C. iron heat resistance test without any cracks, and the wear resistance was superior to that of Example 1.

Example 11
Evaluation was made in the same manner as in Example 1 except that the pipe diameter in the spinning pack was changed and the residence time of the core component was 40 minutes. In Example 11, although the iron heat resistance and wear resistance were excellent, the color tone of the raw machine was slightly yellowish, and the b ^* value in the L ^* a ^* b ^* color system was also 5.2. Moreover, the color tone after dyeing was dull and inferior to Example 1 in terms of sharpness.

Example 12
Example 1 except that the first godet roll and the second godet roll were set to a circumferential speed of 1000 m / min, and the winding speed was 995 m / min, so that the undrawn yarn configuration was 210 dtex and 36 filaments. According to spinning conditions. Further, the undrawn yarn was drawn at a draw ratio of 2.5 times, a drawing temperature of 90 ° C., and a heat setting temperature of 125 ° C. to obtain a drawn yarn of 84 dtex and 36 filaments. In the sample of Example 12, the yarn fluctuated on the heating roll by stretching and the yarn breakage occurred frequently. Moreover, the iron heat resistance and wear resistance of the obtained fabric were both inferior to those of Example 1.

Example 13
Example 1 except that the first godet roll and the second godet roll were set to a peripheral speed of 2000 m / min, and the winding speed was set to 1970 m / min so that the structure of the undrawn yarn was 152 dtex and 36 filaments. According to spinning conditions. Further, the undrawn yarn was drawn at a draw ratio of 1.8 times, a drawing temperature of 90 ° C., and a heat setting temperature of 125 ° C. to obtain a drawn yarn of 84 dtex and 36 filaments. The sample of Example 13 was superior to Example 12 in iron heat resistance. In addition, the wear resistance was at a level where there was no practical problem.

Example 14
Example 1 except that the first godet roll and the second godet roll were rotated at a peripheral speed of 4000 m / min, and the winding speed was 3900 m / min, so that the undrawn yarn configuration was 100 dtex and 36 filaments. According to spinning conditions. The winding tension at this time was 0.12 cN / dtex. Further, the undrawn yarn was drawn at a draw ratio of 1.2 times, a drawing temperature of 90 ° C., and a heat setting temperature of 125 ° C. to obtain a drawn yarn of 84 dtex and 36 filaments. The sample of Example 14 showed excellent characteristics in both iron heat resistance and wear resistance, as in Example 1.

Example 15
Evaluation was made under the same conditions as in Example 2 except that Example 14 was used except that the winding speed was 3960 m / min. The winding tension at this time was 0.20 cN / dtex. In the sample of Example 15, the unwinding tension of the package at the time of drawing was not stable, and 35 pieces of yarn breakage occurred when all the 50 kg of undrawn yarn was drawn. Further, the obtained drawn yarn had thick and thin spots synchronized with the end face period of the undrawn yarn package, and the yarn spot U% was a little bad at 1.7%. Further, the iron heat resistance and wear resistance of the fabric were at a level that had no problem in practice, but there were dyeing spots that seemed to be caused by yarn spots.

Example 16
Evaluation was performed under the same conditions as in Example 1 except that the stretching temperature was 70 ° C. In Example 17, the yarn unevenness U% was as high as 2.3%, and the yarn uniformity was inferior. Further, the iron heat resistance and wear resistance of the fabric were at a level that had no practical problem, but dyeing spots were likely to occur, and it was necessary to limit the use to light dyeing.

Example 17
The undrawn yarn obtained in Example 1 was processed at a speed of 500 m / min, a draw ratio of 1.3 times, a hot plate temperature of 130 ° C., and a D / Y ratio of 1.5 as a triaxial twister (11 sheets, yarn feeding direction) The first, second, and eleventh counts were made of ceramic disks and the others were urethane disks. The yarn threading property and process passability were good, and yarn breakage did not occur. The CR value indicating the crimping property of the obtained yarn was 32%, and a false twisted yarn with good mechanical properties and crimping properties was obtained. When the iron heat resistance and wear resistance of the false twisted yarn were evaluated, the false twisted yarn had excellent characteristics as in Example 1.

  The fiber of the present invention is a composite fiber composed of an aliphatic polyester and a crystalline polyester having a melting point of 200 ° C. or more, and is suitable for applications requiring heat resistance and wear resistance, for example, clothing such as Y-shirts, blouses, and outerwear. Can be used for

It is a figure which shows the fiber cross-sectional shape of the composite yarn preferably used by this invention. It is the schematic for demonstrating the saddle and bulge rate of a cheese-like package. 1 is a schematic view of a spinning device preferably used in the present invention. It is a longitudinal cross-sectional view of the nozzle | cap | die preferably used in order to manufacture the composite yarn of this invention.

Explanation of symbols

1: A component hopper 1 ': B component hopper 2: A component extrusion kneader (extruder)
2 ': B component extrusion kneader (extruder)
3: Metering pump 4: Spinning block 5: Spinning pack 6: Base 7: Cooling device 8: Thread 9: Refueling guide 10: Entangling device 11: First godet roller 12: Second godet roller 13: Winder 14: Winding yarn package

Claims (6)

  The thermoplastic resin forming the core part A is an aliphatic polyester, and the thermoplastic resin forming the sheath part B is a core-sheath composite fiber, which is a crystalline polyester having a melting point of 200 ° C. or higher, and forms the sheath part B. A composite fiber having a crystalline polyester film thickness of 0.4 μm or more.   The composite fiber according to claim 1, wherein the aliphatic polyester forming the core A is polylactic acid having a melting point of 150 ° C or higher.   The composite fiber according to claim 1 or 2, wherein the crystalline polyester forming the sheath part B is a thermoplastic resin selected from polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate.   The composite fiber according to any one of claims 1 to 3, wherein the total carboxyl terminal concentration of the composite fiber is 20 equivalents / ton or less.   The composite fiber according to any one of claims 1 to 4, wherein a compatibilizing agent is contained in the core part and / or the sheath part.   A fiber structure using at least a part of the conjugate fiber according to any one of claims 1 to 5, wherein in a fastness test against friction (friction tester type II), dry grade 3 or higher, wet grade 3 A dyed fiber structure having the above dyeing fastness.

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