JP4661266B2 - Synthetic fiber and fiber structure comprising the same - Google Patents

Description

  The present invention relates to a synthetic fiber in which an aliphatic polyester resin and a thermoplastic polyamide resin are uniformly blended, and the interfacial adhesion is extremely good.

  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, global warming caused by the future depletion of petroleum resources and 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.

  Aliphatic polyester resins represented by polylactic acid have been used for a long time in the medical field, for example, as surgical sutures, but recently, due to the improvement of mass production technology, it has become possible to compete with other general-purpose plastics in terms of price. It was. For this reason, product development as a fiber has been activated.

  The development of aliphatic polyester fibers such as polylactic acid is preceded by agricultural materials and civil engineering materials that make use of biodegradability, followed by large-scale applications such as clothing, interiors such as curtains and carpets, and vehicle interiors. Applications to industrial and industrial materials are also expected. However, the low wear resistance of aliphatic polyesters, particularly polylactic acid, is a major problem when applied to clothing and industrial material applications. For example, when polylactic acid fiber is used for apparel, color transfer easily occurs due to rubbing or the like, and in severe cases, the fiber becomes fibrillated and whitened, causing excessive irritation to the skin. It has been found that the durability of is poor. In addition, when used for automobile interiors, especially carpets that are subject to strong rubbing, the polylactic acid may easily fall down and be scraped, and in severe cases, holes may be formed. In addition, it has been found that aliphatic polyesters (particularly polylactic acid) are likely to be hydrolyzed, and that fibrillation and scraping as described above tend to become severe over time, resulting in a short product life.

  As a method for improving the abrasion resistance of polylactic acid, for example, methods for suppressing hydrolysis are disclosed (Patent Document 1 and Patent Document 2). Patent Document 1 suppresses hydrolysis in the fiber production process by suppressing the water content of polylactic acid as much as possible, and Patent Document 2 improves hydrolysis resistance by adding a monocarbodiimide compound. Disclosed fibers are disclosed. However, although any fiber has a decrease in wear resistance in terms of suppressing the embrittlement of polylactic acid over time, none of them changes the property of polylactic acid “easy to fibrillate” The initial wear resistance was found to be no different from that of conventional products.

  In addition, as a method for greatly improving the wear resistance, polylactic acid fibers in which wear is suppressed by adding a lubricant such as fatty acid bisamide to reduce the friction coefficient of the fiber surface are disclosed (Patent Documents 3 to 3). 6). However, these fibers are effective when the applied force is small, but, for example, when a strong stepping force is applied like a carpet, the adhesion between fibers cannot be sufficiently suppressed. The use was limited.

Moreover, the technique which improves the mechanical characteristics of a resin composition by the blend of polyamide and aliphatic polyester is disclosed (patent document 7). According to the method of Patent Document 7, the mechanical properties such as strength, heat resistance, and wear resistance are improved by the reinforcing effect of the polyamide. However, in this method, the blend ratio of the polyamide is 5 to 40%, which is a small component. In addition, since the aliphatic polyester forms a sea component and the aliphatic polyester and the polyamide are incompatible with each other, the adhesion at the interface between these phases is inferior. It turned out to be a problem of blurring and high wear rate.
JP 2000-136435 A (page 4) JP 2001-261797 A (page 3) JP 2004-91968 A (pages 4-5) JP 2004-204406 A (pages 4-5) JP 2004-204407 A (pages 4 to 5) JP-A-2004-277931 (pages 5-6) JP 2003-238775 A (page 3)

  This invention solves the said subject, and makes it a subject to provide the synthetic fiber and fiber structure which are excellent in abrasion resistance, and can give a high quality fiber structure.

The above-mentioned problem is composed of an aliphatic polyester resin (A), a thermoplastic polyamide resin (B), and a polymer alloy containing a compound (C) selected from the following (1), (2) and a mixture thereof: The synthetic fiber has an island-island structure in which the aliphatic polyester resin (A) forms an island component and the thermoplastic polyamide resin (B) forms an ocean component, and the domain size of the island component is 0.00. It can be achieved by a synthetic fiber characterized by having a diameter of 001 to 3 μm and a fiber structure comprising at least a part of the synthetic fiber.
(1) Compound containing two or more active hydrogen reactive groups in one molecule
(2) Polyalkylene ether glycol having a molecular weight of 400 to 20,000

  According to the present invention, it is possible to provide a synthetic fiber and a fiber structure that are remarkably improved in wear resistance and can provide a high-quality fiber structure, and that are optimal for general clothing use and industrial material use.

  The aliphatic polyester resin (A) in the present invention (hereinafter sometimes referred to as “component A”) refers to a polymer in which aliphatic alkyl chains are linked by ester bonds. As aliphatic polyester resin (A) used by this invention, it is preferable that it is crystalline, and it is more preferable that melting | fusing point is 150-230 degreeC. Examples of the aliphatic polyester resin (A) used in the present invention include polylactic acid, polyhydroxybutyrate, polybutylene succinate, polyglycolic acid, and polycaprolactone. Of these, polylactic acid is most preferred.

The polylactic acid is a polymer having-(O-CHCH ₃ -CO) n- as a repeating unit, and is obtained by polymerizing oligomers of lactic acid such as lactic acid and lactide. 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. As the optical purity of D-lactic acid or L-lactic acid in polylactic acid decreases, the crystallinity decreases and the melting point drop increases. Since the melting point is preferably 150 ° C. or higher in order to maintain the heat resistance of the fiber, the optical purity is preferably 90% or higher.

  However, apart from the system in which the polymers of the two optical isomers are simply mixed as described above, the two optical isomer polymers are blended and formed into a fiber, and then a high temperature of 140 ° C. or higher. A stereo complex in which racemic crystals are formed by heat treatment is preferable because the melting point can be increased to 220 to 230 ° C. In this case, “component A” refers to a mixture of poly (L lactic acid) and poly (D lactic acid). When the blend ratio is 40/60 to 60/40, the ratio of stereocomplex crystals can be increased. Is the best.

  Polylactic acid also contains residual lactide as a low molecular weight residue, but these low molecular weight residues may cause abnormal dyeing such as heating and heater stains in the stretching and false twisting process and dyed spots in the dyeing process. Causes to trigger. In addition, the hydrolysis of fibers and fiber molded products is promoted, and the durability is lowered. Therefore, the amount of residual lactide in polylactic acid is preferably 0.3% by weight or less, more preferably 0.1% by weight or less, and still more preferably 0.03% by weight or less.

  In addition, components other than lactic acid may be copolymerized within a range that does not impair the properties of polylactic acid. The components to be copolymerized include polyalkylene ether glycols such as polyethylene glycol, aliphatic polyesters such as polybutylene succinate and polyglycolic acid, aromatic polyesters such as polyethylene isophthalate, and hydroxycarboxylic acids, lactones, dicarboxylic acids, and diols. An ester bond-forming monomer such as Among these, a polyalkylene ether glycol having good compatibility with the thermoplastic polyamide resin (B) (hereinafter sometimes referred to as “component B”) is preferable. The copolymerization ratio of such a copolymer component is preferably 0.1 to 10 mol% with respect to polylactic acid as long as the heat resistance deterioration due to the melting point drop is not impaired. The molecular weight of the polylactic acid polymer is preferably high in order to increase the wear resistance. However, if the molecular weight is too high, the moldability and stretchability in melt spinning tend to decrease. The weight average molecular weight is preferably 80,000 or more, more preferably 100,000 or more in order to maintain wear resistance. More preferably, it is 120,000 or more. On the other hand, when the molecular weight exceeds 350,000, the stretchability is lowered as described above. As a result, the molecular orientation is deteriorated and the fiber strength is lowered. Therefore, the weight average molecular weight is preferably 350,000 or less, and more preferably 300,000 or less. More preferably, it is 250,000 or less. The weight average molecular weight is a value determined by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

  The method for producing polylactic acid preferably used for “Component A” 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 polyamide resin (B) used in the present invention refers to a polymer having an amide bond. Examples of the thermoplastic polyamide resin (B) used in the present invention include polycoupleramide (nylon 6) and polyundecane. Examples thereof include amide (nylon 11), polydodecanamide (nylon 12), polyhexamethylene sebamide (nylon 610), and the like. Among these, in order to increase the compatibility with Component A, it is better that the methylene chain length of the polyamide is long, and nylon 11, nylon 12, and nylon 610 are preferable in that respect. The polyamide may be a homopolymer or a copolymer.

  In general, when an aliphatic polyester has a melting point, the melting point is usually not higher than 200 ° C., and thus the heat resistance is not high. If the temperature exceeds 250 ° C. during melt storage, the physical properties tend to deteriorate rapidly. Therefore, the thermoplastic polyamide resin (B) to be blended preferably has a melting point of 150 to 250 ° C. The upper limit of the melting point of the thermoplastic polyamide resin is preferably 225 ° C. or lower. On the other hand, considering the heat resistance of the fiber, the lower limit of the melting point of the polyamide is preferably 150 ° C. or higher. As described above, the thermoplastic polyamide resin may be a copolymer. However, since the wear resistance tends to decrease when the crystallinity is lowered, the thermoplastic polyamide resin is preferably crystalline.

  In the present invention, the presence or absence of crystallinity can be determined to be crystalline if the melting peak can be observed by differential scanning calorimetry (DSC) measurement.

The blend ratio of component A and component B of the present invention is not particularly limited, but in order to make a polymer alloy having a sea-island structure in which component A is an island component and component B is a sea component, a blend of component A / component B The ratio (% by weight) is preferably in the range of 5/95 to 55/45. Further, when the ratio of component A is increased, the melt viscosity ηa of component A may be increased, and when the ratio of component B is increased, the melt viscosity ηb of component B may be increased. In the present invention, it is necessary that component A is an island component and component B is a sea component. Therefore, since the blending ratio of component A and component B becomes easier as the ratio of component B is increased, it is more preferably 7/93 to 45/55, more preferably 10/90 to 40/60, and most preferably 15 / 85 to 30/70. The ratio of melt viscosity (ηb / ηa) is preferably in the range of 0.1 to 2.0. More preferably, it is 0.15-1.5, More preferably, it is 0.2-1.0. In addition, although the measuring method of melt viscosity (eta) is mentioned later in detail, it is melt viscosity when it measures with the measurement temperature of 240 degreeC and the shear rate of 1216 sec- ¹ .

  In the present invention, it is important that the component A and the component B are uniformly blended. Here, the term “uniformly blended” refers to the following state. That is, when a cross-sectional slice of the synthetic fiber is observed with a transmission electron microscope (TEM) (40,000 times), a so-called sea-island structure is adopted, and the domain size of the component A constituting the island component is converted into a diameter (domain) Is a circle, and the diameter is converted to 0.001 to 3 μm in terms of the diameter converted from the area of the domain. By setting the domain size of the island component within the above range, the abrasion resistance of the fiber can be dramatically improved. The adhesion with the component B constituting the sea component is improved because the stress concentration at the interface is dispersed as the domain size is smaller. On the other hand, when the domain size is a certain size or less, the initial wear resistance is improved. It tends to decrease. Therefore, the size of the island domain is preferably 0.005 to 1.5 μm, and more preferably 0.01 to 1.0 μm. More preferably, it is 0.02-0.5 micrometer. The domain size in the present invention is the distribution range of domains when measured for 100 domains per sample of synthetic fiber (polymer alloy fiber) as described later in the section G of the examples. It is in range.

  In addition, since the material constituting the synthetic fiber of the present invention is a polymer alloy, unlike a block copolymer in which an aliphatic polyester block and a polyamide block are alternately present in one molecular chain, an aliphatic polyester molecular chain (component It is important that A) and the polyamide molecular chain (component B) exist substantially independently. The difference in this state is that by observing how much the melting point drop of the thermoplastic polyamide resin before and after blending, that is, how much the melting point derived from the thermoplastic polyamide resin in the polymer alloy dropped from the melting point of the thermoplastic polyamide resin before blending. Can be estimated. If the melting point drop of the thermoplastic polyamide resin is 3 ° C. or less, the aliphatic polyester and the polyamide are hardly copolymerized (almost no ester-amide exchange occurs), and the aliphatic polyester molecular chain is substantially The polyamide molecular chain is a polymer alloy that exists independently. Further, since the fiber surface layer is a thermoplastic polyamide resin that is substantially a sea component, the inherent properties of the thermoplastic polyamide resin are reflected, and the wear resistance is dramatically improved. Therefore, in the present invention, the melting point drop of the blended polyamide is preferably 2 ° C. or less.

The synthetic fiber of the present invention is a synthetic fiber composed of an aliphatic polyester resin and a polymer alloy containing a thermoplastic polyamide resin as described above. The aliphatic polyester resin is an island component, and the thermoplastic polyamide resin is a sea component. A sea-island structure is formed. In addition, the wear resistance is dramatically improved by controlling the domain size of the island component. Here, as described above, since the aliphatic polyester and the polyamide usually hardly react (ester-amide exchange hardly occurs), the interfacial adhesion of the two polymers is not so high as it is. Therefore, the synthetic fiber of the present invention further improves the abrasion resistance by further adding the compound (C) (hereinafter sometimes referred to as “component C”) to dramatically improve the interfacial adhesion. . Component C is not particularly limited as long as it improves the interfacial adhesion between Component A and Component B, but when it is a compound having two or more active hydrogen reactive groups in one molecule, Interfacial adhesion can be dramatically improved, which is preferable. A compound having two or more active hydrogen reactive groups in one molecule is added to component A and / or component B and melt blended to perform spinning, so that the compound is any component of component A and component B. Since both react with each other to form a cross-linked structure, interfacial peeling can be suppressed.

Here, the active hydrogen reactive group is a group having reactivity with a COOH terminal group, an OH terminal group, or an NH ₂ terminal group present at the terminal of a polylactic acid resin or a thermoplastic polyamide resin, such as a glycidyl group or an oxazoline. Group, carbodiimide group, aziridine group, imide group, isocyanate group, maleic anhydride group and the like are preferably used. Further, in melt spinning, which is a method for producing a synthetic fiber according to the present invention, molding is performed at a relatively low temperature of 250 ° C. or lower, and therefore, one having excellent low temperature reactivity is selected. Among the above reactive groups, glycidyl groups, oxazoline groups, carbodiimide groups, acid anhydride groups (groups formed from maleic anhydride (sometimes referred to as maleic anhydride groups), etc.) are preferably used, especially glycidyl groups and carbodiimides. A group is preferably used. If the number of the reactive groups is two or more, the role can be satisfied. On the other hand, if there are more than 20 reactive groups in one molecule, the viscosity tends to be excessively increased during spinning and the spinnability tends to decrease. Therefore, the number of active hydrogen reactive groups in one molecule is 2 More than 20 and 20 or less are preferable. More preferably, it is 10 or less, and more preferably 3 or less. Moreover, the kind of reactive group in one molecule may include a plurality. Moreover, it is preferable that the compound having two or more active hydrogen reactive groups has a weight average molecular weight of 250 to 30,000 because of excellent heat resistance and dispersibility during melt molding. More preferably, it is 250-20,000.

  Moreover, as a compound having such a reactive group, a copolymer obtained by graft copolymerizing a side chain having a reactive group on the main chain of the polymer may introduce a large number of functional groups in one molecule. In addition, the thermal properties such as the melting point are generally stable. The polymer to be the main chain to which this reactive group is grafted can be arbitrarily selected, but for ease of synthesis, polyester polymer, polyacrylate, polymethyl methacrylate, poly (alkyl) meta. It can be appropriately selected from the group of acrylate polymers such as acrylate, polystyrene polymers, polyolefin polymers and the like.

  Among the components C that can be used in the present invention, as the compound having a glycidyl group, for example, a polymer having a monomer unit of a compound having a glycidyl group, or a glycidyl group graft-copolymerized to a main chain polymer. And those having a glycidyl group at the end of the polyether unit. Examples of the monomer unit having a glycidyl group described above include glycidyl acrylate and glycidyl methacrylate. In addition to these monomer units, a long-chain alkyl acrylate or the like may be copolymerized to control the reactivity of the glycidyl group. Moreover, the polymer whose monomer unit is a compound having a glycidyl group or the average molecular weight of the polymer as the main chain is in the range of 250 to 30,000, suppresses an increase in melt viscosity when a high concentration is added. This is preferable. The weight average molecular weight is more preferably in the range of 250 to 20,000. In addition, a compound having two or more glycidyl units in the triazine ring is preferable because of high heat resistance. For example, triglycidyl isocyanurate (TGIC), monoallyl diglycidyl isocyanurate (MADGIC) and the like are preferably used.

  The same applies to the oxazoline group, carbodiimide group, aziridine group, imide group, isocyanate group, and maleic anhydride group. Among the above, those having a carbodiimide group are more preferable because of extremely excellent low-temperature reactivity. For example, examples of the carbodiimide compound 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-phene Len-bis-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-nitro Phenylcarbodiimide, 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, '-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-trimethylphenyl Mono- or dicarbodiimide compounds such as carbodiimide, N, N′-di-2,4,6-triisopropylphenylcarbodiimide, N, N′-di-2,4,6-triisobutylphenylcarbodiimide, poly (1,6 -Hexamethylenecarbodiimide), poly (4,4'-methylenebiscyclohexylcarbodi) Imide), poly (1,3-cyclohexylenecarbodiimide), poly (1,4-cyclohexylenecarbodiimide), poly (4,4'-diphenylmethanecarbodiimide), poly (3,3'-dimethyl-4,4'- Diphenylmethanecarbodiimide), poly (naphthylenecarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (tolylcarbodiimide), poly (diisopropylcarbodiimide), poly (methyl-diisopropylphenylenecarbodiimide), poly ( And polycarbodiimides such as triethylphenylenecarbodiimide) and poly (triisopropylphenylenecarbodiimide). Of these, polymers of N, N′-di-2,6-diisopropylphenylcarbodiimide and 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide are preferable.

  Further, the two or more active hydrogen reactive groups may be the same reactive group or different, but are preferably the same reactive group in order to control the reactivity.

  As the compound used as Component C, polyalkylene ether glycol is preferable because it specifically improves wear resistance in addition to the compound having the active hydrogen reactive group. Examples of the compound include polyethylene glycol, polypropylene glycol, polybutylene glycol, etc. Among them, polyethylene glycol having a molecular weight of 400 to 20,000 is preferable in terms of heat resistance, dispersibility, and price. More preferred is polyethylene glycol having a molecular weight of 600 to 6,000. Moreover, it is more preferable if both ends of the compound are modified to glycidyl groups. It is also preferred to use in combination with a compound having two or more active hydrogen reactive groups.

  Moreover, since the compound used as Component C is usually melt-molded into a fiber at 200 to 250 ° C. in producing the synthetic fiber of the present invention, high heat resistance that can withstand it is required. Therefore, it is preferable that the thermal weight loss rate at the 200 ° C. arrival point by thermogravimetry (TG) measurement is 3% or less. If the heat loss rate exceeds 3%, the pyrolysate bleeds out during spinning, and the spinneret and spinning device are soiled, resulting in a decrease in spinnability and a tendency to deteriorate the working environment due to fuming of pyrolysis gas. There is a point. More preferably, the heat loss rate is 2% or less, and further preferably 1% or less. The 200 ° C. heat loss rate is measured by measuring the weight loss rate at 200 ° C. by raising the temperature from normal temperature (10-30 ° C.) to 300 ° C. at a rate of 10 ° C./minute in a thermogravimetric (TG) measurement. It is what I have sought.

  The amount of component C added is appropriately determined according to the equivalent weight per unit weight of the reactive group of the compound used, the dispersibility and reactivity at the time of melting, the size of the island component domain, and the blend ratio of component A and component B. Can do. In terms of suppressing interfacial peeling, the content is preferably 0.005% by weight or more with respect to the total amount (100% by weight) of Component A, Component B and Component C. More preferably, it is 0.02 weight% or more, More preferably, it is 0.1 weight% or more. When the amount of component C added is too small, the diffusion and reaction amount at the interface between the two components is small, and the effect of improving the interfacial adhesion becomes limited. On the other hand, the amount of component C added is preferably 5% by weight or less in order for component C to exhibit performance without impairing the properties of component A and component B, which are the base material of the fiber, and the spinning performance. % Or less is more preferable. More preferably, it is 1 weight% or less.

  As described above, by adding Component C, the terminal carboxyl group of the aliphatic polyester can be blocked, and the hydrolysis resistance of the aliphatic polyester can be improved. The concentration of the terminal carboxyl group having an autocatalytic action should be low, and the total carboxyl end group concentration in the aliphatic polyester is preferably 15 equivalents / ton or less, more preferably 10 equivalents / ton or less, and still more preferably 0 to 7 equivalents / ton.

  Furthermore, for the purpose of promoting the reaction of the compound having a reactive group, it is preferable to add a metal salt of a carboxylic acid, particularly a catalyst in which the metal is an alkali metal or an alkaline earth metal because the reaction efficiency can be increased. Among these, it is preferable to use a catalyst based on lactic acid such as sodium lactate, calcium lactate and magnesium lactate. In addition, a catalyst having a relatively large molecular weight such as a metal stearate can be used alone or in combination for the purpose of preventing the heat resistance of the resin from being lowered due to the addition of the catalyst. The added amount of the catalyst is preferably 5 to 2000 ppm with respect to the synthetic fiber in order to control dispersibility and reactivity. More preferably, it is 10-1000 ppm, More preferably, it is 20-500 ppm.

The synthetic fiber of the present invention preferably has a strength of 1.0 cN / dtex or more, more preferably 2.0 cN / dtex or more in order to keep the process passability and product mechanical strength high. More preferably, it is 3.0 cN / dtex or more. Synthetic fibers having such strength can be produced by a melt spinning method and a drawing method described later.
Further, it is preferable that the elongation is 15 to 70% because the process passability when the fiber product is made is good. Synthetic fibers having such elongation can be produced by a melt spinning method and a drawing method described later.

  Further, if the boiling water shrinkage of the fiber is 0 to 20%, the dimensional stability of the fiber and the fiber product is good, which is preferable. In addition, conventional polymer alloy fibers (synthetic fibers) of aliphatic polyester and polyamide tend to be thick and thin in the process of thinning deformation by melt spinning, and have a problem in quality such as yarn spots. Since the two components are uniformly dispersed and have excellent fiber-forming properties, the yarn spots are small. The fiber of the present invention preferably has 2.0% or less, more preferably 1.0% or less, in order to suppress process passability and dyed spots after dyeing. More preferably, it is 0.5% or less.

  The cross-sectional shape of the fiber of the present invention can be freely selected for a round cross-section, a hollow cross-section, a porous hollow cross-section, a multi-leaf cross-section such as a trilobal cross-section, a flat cross-section, a W cross-section, an X cross-section, and other irregular cross sections. . The form of the fiber is not particularly limited, such as long fiber or short fiber, and in the case of long fiber, it may be multifilament or monofilament.

  Moreover, when using the fiber of this invention as a fiber structure, it can apply to a textile fabric, a knitted fabric, a nonwoven fabric, a pile, cotton, etc., and may contain the other fiber. For example, it may be natural fiber, recycled fiber, semi-synthetic fiber, alignment with synthetic fiber, twisted yarn, mixed fiber. Other fibers include natural fibers such as cotton, hemp, wool, and silk, regenerated fibers such as rayon and cupra, semi-synthetic fibers such as acetate, nylon, polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), polyacrylonitrile In addition, synthetic fibers such as polyvinyl chloride are applicable.

  In addition, as an application of the fiber structure using the fiber of the present invention, clothing that requires wear resistance, for example, outdoor wear, golf wear, athletic wear, ski wear, snowboard wear and sportswear such as pants thereof, There are women's and men's outerwear such as casual wear such as blousons, coats, winter clothes and rainwear. In addition, applications that require excellent durability and moisture aging characteristics over long periods of use include uniforms, comforters and mattresses, skin comforters, kotatsu comforters, cushions, baby comforters, blankets, etc., pillows, cushions, etc. There are uses for bedding materials such as side covers and covers, mattresses and bed pads, hospital sheets, medical sheets, hotel sheets and baby sheets, as well as covers for sleeping bags, cradle and strollers, etc. be able to. Moreover, it can be used suitably for interior materials for automobiles, and among them, it is optimal to use for automobile carpets that require high wear resistance and moisture aging characteristics. In addition, it is not limited to these uses, For example, you may use for the grassproof sheet for agriculture, the waterproof sheet for building materials, etc.

  Although the manufacturing method of the fiber of this invention is not specifically limited, For example, the following methods are employable.

That is, biaxial extrusion kneading at 230 to 240 ° C. while separately measuring an aliphatic polyester resin (component A) such as poly L-lactic acid, a thermoplastic polyamide resin (component B) such as nylon 6 and component C such as polycarbodiimide. Kneading using a machine to produce a polymer alloy (Note that the polymer alloy used in the present invention is further modified with particles, crystal nucleating agent, flame retardant, plasticizer, antistatic agent, antioxidant and ultraviolet absorber. Additives such as additives and lubricants described in Patent Document 3 may be incorporated, and the blending method is not particularly limited, and the above-described twin-screw extruder kneader may or may not be premixed with components A to C. And may be blended in advance with Component A, Component B, or Component A, B). At this time, as a method of controlling the island domain size, the ratio of the two components (aliphatic polyester resin and thermoplastic polyamide resin) and the blend ratio, the component C to be selected and the addition amount are adjusted within the above-mentioned range. It can be controlled by kneading at a shear rate of 200 to 20,000 sec ⁻¹ and a residence time of 0.5 to 30 minutes. As a method for reducing the island domain size, a lower kneading temperature in the above range is preferable, a higher shear rate is better, and a shorter residence time is better. The obtained polymer blend resin is further fibrillated by a melt spinning method. In this case as well, in order to suppress reaggregation of island domains (component A), a high mesh filter layer (# 100 to # 200) or Ingenuity such as incorporating porous metal, a non-woven filter with a small filtration diameter (filtration diameter of 5 to 30 μm), and a blend mixer (static mixer or high mixer) in the pack is necessary.

  In addition, polymer blends of aliphatic polyesters and polyamides are incompatible, and the melt exhibits a strong behavior with an elastic term, causing bulges called ballas after spinning, making the thinning and deformation unstable. Tend. Methods for suppressing this include increasing the spinning temperature to lower the elongational viscosity, increasing the discharge hole diameter of the spinneret, reducing the discharge linear velocity (polymer flow rate at the final throttle portion of the discharge hole), A method of increasing L / D, which is a ratio of the length to the hole diameter, a method of rapidly cooling the discharged yarn, and the like are effective. The spinning temperature can be determined by the melting point of component B (polyamide), and the optimum range is the melting point Tmb + 10 ° C. to Tmb + 40 ° C. of component B (for example, 210 to 240 ° C. when the melting point Tmb of component B is 200 ° C.). . Further, the discharge linear velocity for suppressing the swelling of the discharge yarn due to the ballast and stabilizing the thinning / deformation is preferably 1 to 20 m / min, more preferably 2 to 15 m / min, and further preferably 3 ~ 12 m / min. Moreover, L / D becomes like this. Preferably it is 0.6-10, More preferably, it is 0.8-7, More preferably, it is 1-5. Further, the cooling start position is preferably 0.01 to 0.2 m, more preferably 0.015 to 0.15 m from the base surface. More preferably, it is 0.02-0.1 m. Further, the optimum value of the spinning speed varies depending on the ratio of the melt viscosity of component A and component B and the blend ratio, but is preferably about 500 to 5,000 m / min. In addition, when the fiber of the present invention is left in an unstretched fiber state, orientation relaxation is likely to occur, and if there is a time difference until stretching between unstretched packages, the fiber's strength and heat shrinkage characteristics easily vary. Therefore, it is preferable to employ a direct spinning drawing method in which spinning and drawing are performed in one step. The stretching temperature and heat setting temperature can be determined by the glass transition points and melting points of component A and component B. The stretching temperature is 20 to 80 ° C and the heat setting temperature is Tmb-20 ° C to Tmb-150 ° C. it can.

  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 a chloroform solution of a sample (aliphatic polyester polymer) to obtain a measurement solution. This was measured by gel permeation chromatography (GPC), and the weight average molecular weight was determined in terms of polystyrene.

B. Residual lactide amount of polylactic acid 1 g of a sample (polylactic acid polymer) was dissolved in 20 ml of dichloromethane, and 5 ml of acetone was 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 amount of lactide was calculated | required with the absolute calibration curve.

C. Carboxyl group end concentration A precisely weighed sample (aliphatic polyester polymer extracted by the following method) was dissolved in o-cresol (water 5%), and an appropriate amount of dichloromethane was added to this solution, followed by 0.02N KOH methanol solution. Determined by titration with 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. The method for extracting the aliphatic polyester from the polymer alloy fiber (synthetic fiber) is not particularly limited, but in the present invention, the aliphatic polyester is dissolved using chloroform or dichloromethane, filtered to remove the polyamide, and the filtrate is dried. Extracted.

D. Relative Viscosity and Intrinsic Viscosity of Thermoplastic Polyamide Nylon 6 was measured at 25 ° C. by preparing a 98% sulfuric acid solution of 0.01 g / mL.
The intrinsic viscosity of nylon 11 was measured at 20 ° C. by preparing a 0.5% by weight metacresol solution.

E. Polymer melting point Using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc., the melting point (° C.) is the temperature that gives the extreme value of the melting endotherm curve obtained by measuring 20 mg of the sample at a heating rate of 16 ° C./min. It was.

F. Melt viscosity η
Using the Capillograph 1B manufactured by Toyo Seiki Co., Ltd., the melt viscosity of each of the aliphatic polyester resin and the thermoplastic polyamide resin was measured at a temperature of 240 ° C. and a shear rate of 1216 sec ⁻¹ in a nitrogen atmosphere. The measurement was performed 3 times and the average value was taken as the melt viscosity.

G. Size of island domains in synthetic fibers Cut out ultrathin sections in the direction perpendicular to the fiber axis of polymer alloy fibers (synthetic fibers), and metal-stain the polyamide component of the sections with phosphotungstic acid, and a 40,000 times transmission electron microscope The blend state was observed and photographed with (TEM). Using the image analysis software “WinROOF” of Mitani Shoji Co., Ltd. for this photographed image, assuming that the domain is a circle as the size of the island domain (non-stained part), the diameter (diameter converted) (2r) converted from the domain area ) As the domain size. The number of domains to be measured was 100 per sample, and the distribution was defined as the island component domain size (island domain size).
TEM equipment: Hitachi H-7100FA type Condition: Acceleration voltage 100 kV

H. Thermal loss rate of component C Using a TG / DTA6200 of EXSTAR6000 series manufactured by SII, about 10 mg of a sample (component C) was weighed, and a thermal loss curve of 200 ± 0.5 ° C. measured at a heating rate of 10 ° C./min. The point weight loss rate was determined.

I. Strength and elongation Sample (polymer alloy fiber (synthetic fiber)) is stretched at a constant speed as shown in JIS L1013 (chemical fiber filament yarn test method, 1998) by TENSILON UCT-100 manufactured by Orientec Co., Ltd. Measured with The elongation at break was determined from the elongation at the point showing the maximum strength in the SS curve.

J. et al. Boiling water shrinkage (boiling yield)
A sample (polymer alloy fiber (synthetic fiber)) was immersed in boiling water for 15 minutes, and obtained from the following equation from the dimensional change before and after immersion.
Boiling water shrinkage (%) = [(L0−L1) / L0] × 100
L0: A skein length measured by scraping a sample and measuring it under an initial load of 0.088 cN / dtex.
L1: A skein length measured under an initial load of 0.088 cN / dtex after treating the skein measured L0 with boiling water in a load-free state and air-drying.

K. Yarn spots U%
Using synthetic fiber (polymer alloy fiber) as a sample, U% (Normal) was measured at a yarn speed of 200 m / min and a measurement time of 1 minute using UT4-CX / M manufactured by Zellweger uster.

L. Deformation of cross section A cross section of a synthetic fiber (polymer alloy fiber) yarn was cut out and obtained from the diameter D of the circumscribed circle of the single fiber cross section and the diameter d of the inscribed circle of the single fiber cross section by the following equation.
Deformity = D / d

M.M. Abrasion resistance evaluation Using a Twain abrasion tester manufactured by Ando Iron Works, No. P600 sandpaper was wound around a roller, and the roller was rotated under the following conditions to measure the number of roller rotations until thread cutting.
Rotating body diameter: 40mm
Yarn contact length: 110 mm
Roller rotation speed: 200rpm
Measurement load: 0.4 cN / dtex

N. Iron heat resistance Using a steam iron A-1F manufactured by Sanyo Electric Co., Ltd. as a fabric made of a sample, when the iron surface temperature reaches 170 ° C., the fabric is ironed by its own weight (surface pressure of about 8 g / cm ² ). Press for 2 seconds, and 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”.

[Production Example 1] (Production of polylactic acid)
Polymerization of lactide produced from L-lactic acid having an optical purity of 99.5% in the presence of bis (2-ethylhexanoate) tin catalyst (lactide to catalyst molar ratio = 10000: 1) at 180 ° C. for 220 minutes in a nitrogen atmosphere. Polylactic acid P1 was obtained. The obtained polylactic acid had a weight average molecular weight of 212,000. The amount of lactide remaining was 0.12% by weight.

[Production Example 2] (Production of polylactic acid containing 10% by weight of MADGIC)
After drying P1 and monoallyl diglycidyl isocyanuric acid (hereinafter referred to as MADGIC) manufactured by Shikoku Kasei Co., Ltd., it is supplied to a twin-screw kneading extruder so that P1: MADGIC = 90: 10 (weight ratio). By kneading at a cylinder temperature of 200 ° C., polylactic acid P2 containing 10% by weight of MADGIC was obtained. The amount of residual lactide of the obtained polylactic acid was 0.15% by weight.

[Production Example 3] (Production of polylactic acid containing 10% by weight of polycarbodiimide)
After drying P1 and polycarbodiimide “LA-1” manufactured by Nisshinbo Co., Ltd., it was supplied to a twin-screw kneading extruder so that P1: LA-1 = 90: 10 (weight ratio), and the cylinder temperature was 200 ° C. By kneading, polylactic acid P3 containing 10% by weight of LA-1 was obtained. The amount of residual lactide of the obtained polylactic acid was 0.15% by weight.

[Production Example 4] (Production of polylactic acid containing 10% by weight of PEG 1000)
After P1 and Sanyo Chemical Co., Ltd. PEG1000 were dried, they were supplied to a twin-screw kneading extruder so that P1: PEG = 90: 10 (weight ratio), and kneaded at a cylinder temperature of 200 ° C. to give 10% by weight of PEG1000. The contained polylactic acid P4 was obtained. The amount of residual lactide of the obtained polylactic acid was 0.15% by weight.

[Production Example 5] (Production of polylactic acid)
Polymerization of lactide produced from L-lactic acid with an optical purity of 99.5% in the presence of bis (2-ethylhexanoate) tin catalyst (lactide to catalyst molar ratio = 10000: 1) at 180 ° C. for 150 minutes in a nitrogen atmosphere. This gave polylactic acid P5. The weight average molecular weight of the obtained polylactic acid was 150,000. The amount of residual lactide was 0.10% by weight.

Example 1
Polylactic acid P1 (melting point: 172 ° C.), Nylon 6 (melting point: 225 ° C.) with sulfuric acid relative viscosity of 2.15 as component B, and P3 (MADGIC: 10% by weight) were dried to adjust the water content to 50-100 ppm. Blend ratio P1 / component B / P2 = 27/70/3 (concentration of component C with respect to the total amount of component A and component B: 0.3 wt%, component A / component B (blend ratio) = 29.8) /70.2, (Blend ratio is the ratio of component A to component B in the resin composition constituting the fiber. That is, component A includes the polylactic acid component in P1 and P3. Also in the following examples) 1), and is fed into a spinning hopper 1 of a spinning device equipped with a biaxial kneader shown in FIG. 1 and led to a biaxial extrusion kneader 2 where the molten polymer is measured and discharged in a spinning block 3 and incorporated. Molten polymer in the spun pack 4 Was spun from the spinneret 5. At this time, the monomer suction device 6 was installed at a position 10 cm below the base, and the yarn 8 was cooled and solidified by the uniflow cooling device 7 while removing the sublimated monomers and oligomers. Oil was supplied by the oil supply device 9. Further, after being taken up by the first take-up roll 10, it was taken up by the winder 12 through the second take-up roll 11, and 168 decitex, 12 filaments of undrawn yarn (winding yarn (cheese package)) The melt viscosity of component A was 203 Pa · s, the melt viscosity of component B was 58 Pa · s, and the melt viscosity ratio ηb / ηa was about 0.29. The heat loss rate at 200 ° C. of Component C was 0.8%, and the melt spinning conditions were as follows: The discharge linear velocity in the die hole under the following conditions was 10.9 m / min, In conversion L / D is 1.2, and the cooling start position is 0.1 m below the base surface.
-Kneader temperature: 230 ° C
-Spinning temperature: 240 ° C
Filter layer: 30 # Morundum sand filling Filter: 20 μm non-woven filter Filter base: Y-shaped hole with slit width 0.2 mm, slit length 0.3 mm, hole depth 0.6 mm Discharge amount: 33.6 g / min ( 1 pack 1 thread, 12 filaments)
・ Cooling: Uniflow using a cooling length of 1 m. Cooling air temperature 20 ° C., wind speed 0.5 m / sec ・ Oil agent: 10% fatty acid ester concentration emulsion oil adhered to yarn 10% ・ Spinning speed: 2000 m / min

  Further, this undrawn yarn was preheated with the first hot roll 16 from the obtained wound yarn (cheese package) 14 through the supply roll 15 using the drawing apparatus shown in FIG. Stretching at a stretching temperature of 80 ° C. and a stretching ratio of 2.0 times, performing heat setting at the second hot roll 17 at a heat setting temperature of 130 ° C., winding up through the cold roll 18, and 84 dtex through the ring rail 19, A 12-filament drawn yarn (winding yarn (pan) 19) was obtained. Got. About 100 kg of spinning was sampled, but no yarn breakage or single yarn flow occurred, and the spinning was extremely stable. Similarly, the whole undrawn yarn was drawn, but no yarn breakage occurred.

  When the cross section of the obtained fiber was observed with a TEM, it was found to have a uniformly dispersed sea-island structure, and the island domain size was 0.03 to 0.3 μm in terms of diameter. Moreover, when the section of the yarn cross section was alkali etched to dissolve and remove polylactic acid, the island component was missing, and it was confirmed that polylactic acid formed the island component. Further, the degree of irregularity of the obtained fiber was 1.6, the strength was 3.5 cN / dtex, the elongation was 41%, the boiling water shrinkage was 10%, and the yarn unevenness U% was 0.6%. . Further, melting points by DSC were around 170 ° C. (polylactic acid) and around 225 ° C. (nylon 6), and melting peaks attributable to each component were observed. Moreover, the carboxyl group terminal density | concentration of the polylactic acid extracted from this fiber was 5 equivalent / ton. Furthermore, the number of rotations of yarn cutting by the abrasion test was 202, and there was no fibrillation at the time of the test, and good abrasion resistance was shown.

  Further, when the taffeta was prepared using the multifilament and evaluated, it was a high-grade fabric having soft and silky gloss. Also, in the iron heat resistance test at 170 ° C., there were no gloss spots or iron marks, and there was no change in tactile sensation.

Example 2
Example 1 except that the blend ratio of P1 / component B / P2 (MADGIC: 10% by weight) was changed to 5/92/3 (the concentration of component C with respect to the total amount of component A and component B: 0.3% by weight). In the same manner, a multifilament was obtained. In Example 2, both spinnability and stretchability were extremely stable as in Example 1. When the TEM observation of the cross section of the obtained fiber was performed, the sea island structure was uniformly dispersed, and the island domain size was 0.01 to 0.15 μm in terms of diameter, and the island components were more dispersed than in Example 1. The diameter was small. Further, when the section of the yarn cross section was alkali etched to dissolve and remove the polylactic acid, the island component was missing, and it was confirmed that the polylactic acid formed the island component. Further, the degree of irregularity of the obtained fiber was 1.4, and the fiber physical properties were also good. Further, melting points by DSC were around 170 ° C. (polylactic acid) and around 225 ° C. (nylon 6), and melting peaks attributable to each component were observed. The obtained multifilament had a yarn cutting rotational speed of 405 according to the abrasion test, which was superior to that of Example 1.

  Further, when a taffeta was prepared using the multifilament and evaluated, a soft fabric was obtained, but the gloss was slightly duller than Example 1. Further, the iron heat resistance test at 170 ° C. showed excellent characteristics as in Example 1.

Example 3
The P1 polymer was crystallized by treatment at 100 ° C. for 2 hours under a nitrogen atmosphere, and further treated at 130 ° C. for 48 hours under vacuum to prepare polylactic acid P6 having a residual lactide amount of 0.03 weight. Next, except that the blend ratio of P6 / component B / P2 (MADGIC: 10% by weight) was 37/60/3 (the concentration of component C with respect to the total amount of component A and component B: 0.3% by weight) A multifilament was obtained in the same manner as in Example 1. In Example 2, both spinnability and stretchability were stable as in Example 1, and in particular, smoke generation just below the base during spinning (smoke caused by lactide) was significantly suppressed, and the spinning environment was extremely good. . When the TEM observation of the cross section of the obtained fiber was performed, it took a relatively uniformly dispersed sea-island structure, and the island domain size was 0.03-0.8 μm in terms of diameter, which is larger than Example 1. The island dispersion diameter. Further, when the section of the yarn cross section was alkali etched to dissolve and remove the polylactic acid, the island component was missing, and it was confirmed that the polylactic acid formed the island component. The number of yarn cutting rotations by the abrasion test of the obtained multifilament was 127, which was slightly inferior to that of Example 1, but at a level causing no practical problems.

  Further, when a taffeta was prepared and evaluated using the multifilament, a soft and silky glossy fabric was obtained as in Example 1. In the iron heat resistance test at 170 ° C., some ironing was observed.

Example 4
Example 1 except that the blend ratio of P1 / component B / P2 (MADGIC: 10% by weight) was 47/50/3 (the concentration of component C with respect to the total amount of component A and component B: 0.3% by weight) In the same manner, a multifilament was obtained. In Example 4, two yarn breaks occurred while sampling 100 kg of undrawn yarn. Therefore, when the state of the spinning part was observed, it was observed that the bulge of the yarn called the ballus had a diameter about twice that of Example 1, and that the position of the finer deformation fluctuated up and down. It was done. Further, the yarn breakage occurred five times in the drawing. When the TEM observation of the cross section of the obtained fiber was performed, a co-continuous structure in which the island domain size was slightly non-uniform as 0.05 to 1.5 μm in diameter and the islands were partially bonded was observed. Further, when the section of the yarn cross section was alkali etched to dissolve and remove the polylactic acid, the island component was missing, and it was confirmed that the polylactic acid formed the island component. The number of yarn cutting rotations by the abrasion test of the obtained multifilament was 105, which was considerably inferior to that of Example 1, but was a level that could be used by limiting the application.

  Further, when a taffeta was prepared and evaluated using the multifilament, a soft and silky glossy fabric was obtained as in Example 1. Further, in the iron heat resistance test at 170 ° C., a clear iron attack was observed, and the iron heat resistance test was limited to a low-temperature iron.

Example 5
A multifilament was obtained in the same manner as in Example 1 except that polylactic acid P5 (melting point: 170 ° C.) and nylon 11 (melting point: 186 ° C.) having an intrinsic viscosity of 1.45 were used as Component B. In Example 5, both spinnability and stretchability were stable as in Example 1. When the TEM observation of the cross section of the obtained fiber was performed, it took a relatively uniformly dispersed sea island structure, and the island domain size was 0.05 to 0.5 μm in terms of diameter, which is larger than Example 1. The island dispersion diameter. Further, when the section of the yarn cross section was alkali etched to dissolve and remove the polylactic acid, the island component was missing, and it was confirmed that the polylactic acid formed the island component. The number of yarn cutting rotations by the abrasion test of the obtained multifilament was 155 times, which was slightly inferior to Example 1, but at a level causing no practical problems.

  Further, when a taffeta was prepared and evaluated using the multifilament, a soft and silky glossy fabric was obtained as in Example 1. Further, in the iron heat resistance test at 170 ° C., a clear iron attack was observed, and the iron heat resistance test was limited to a low-temperature iron.

Comparative Example 1
A multifilament was obtained in the same manner as in Example 5 except that the blend ratio of P5 / component B was 65/35 (component C was not added). In Comparative Example 1, both spinnability and stretchability were stable as in Example 1. When the TEM observation of the cross section of the obtained fiber was performed, it took a relatively uniformly dispersed sea island structure, and the island domain size was 0.05 to 0.5 μm in terms of diameter. When the slices of the sample were alkali etched to dissolve and remove polylactic acid, most of the sea components were missing, and it was confirmed that polylactic acid formed sea components. The obtained multifilament had a yarn cutting rotational speed of 41 times according to the abrasion test, which was superior to a polylactic acid single yarn (Comparative Example 2) described later, but the use was considerably limited.

  Furthermore, when the taffeta was prepared using the multifilament and evaluated, it had a slightly rough feel compared to Example 1 although it had a silky gloss. Further, in the iron heat resistance test at 170 ° C., partial fusion occurred between the fibers, and the coarseness was further increased.

Comparative Example 2
A multifilament was obtained in the same manner as in Example 1 except that only component A (polylactic acid P1) was used. In Comparative Example 2, both spinnability and stretchability were stable as in Example 1. The obtained multifilament had a yarn cutting rotational speed of 15 times by an abrasion test and was extremely inferior in wear resistance. In addition, when the taffeta was made using the multifilament and evaluated, it had a silky glossy feeling, but had a rough and hard feeling, and in the iron heat resistance test at 170 ° C. It melted and there was a hole.

Comparative Example 3
Example 1 except that the blend ratio of P5 / component B / P2 (MADGIC: 10% by weight) was 47/50/3 (the concentration of component C with respect to the total amount of component A and component B: 0.3% by weight) In the same manner, a multifilament was obtained. Comparative Example 3 was the same as in Example 1 except that polylactic acid P5 (melting point: 170 ° C.) was used as component A and nylon 6 (melting point: 225 ° C.) having a relative viscosity of sulfuric acid of 2.85 was used as component B. Obtained. The melt viscosity of component A was 116 Pa · s, the melt viscosity of component B was 238 Pa · s, and the melt viscosity ratio ηb / ηa was about 2.05. In Comparative Example 3, thinning of the yarn was extremely unstable during melt spinning, and the thinning deformation point moved up and down violently to form thick and thin yarn breaks. Similarly, yarn breakage frequently occurred in stretching. When the TEM observation of the yarn cross-section was performed, the island domain size was large and exceeded 3 μm in terms of diameter. Further, the yarn unevenness U% was as large as 6.3%, and the fiber physical properties were extremely inferior to those of Example 1. Further, the number of yarn cutting rotations by the abrasion test of the obtained multifilament was 36, which was a level where the application was considerably limited.

Example 6
As component C, P3 (polycarbodiimide “LA-1”: 10% by weight) is used instead of polylactic acid P2, and the blend ratio is P1 / component B / P3 = 20/70/10 (total of component A and component B) A multifilament was obtained in the same manner as in Example 1 except that the concentration of component C relative to the amount was 1.0 wt%. In Example 6, as in Example 1, both spinning and drawing were good, and 100 kg of drawn yarn could be sampled without breakage. Moreover, when the TEM observation of the cross section of the obtained fiber was performed, it had a uniformly dispersed sea-island structure, and the island domain size was 0.03 to 0.3 μm in terms of diameter, as in Example 1. The dispersion diameter of the components was small. Further, when the section of the yarn cross section was alkali etched to dissolve and remove the polylactic acid, the island component was missing, and it was confirmed that the polylactic acid formed the island component. Further, the degree of irregularity of the obtained fiber was 1.7, and the fiber physical properties were also good. The number of yarn cutting rotations by the abrasion test of the obtained multifilament was 228 times, which was superior to Example 1.

  Further, when the taffeta was prepared and evaluated using the multifilament, both the soft feeling and the glossiness were at the same level as in Example 1, but the color tone was slightly yellowish. Further, the iron heat resistance test at 170 ° C. showed excellent characteristics as in Example 1.

Example 7
As component C, P4 (PEG 1000: 10% by weight) is used instead of polylactic acid P2, and the blend ratio is P1 / component B / P4 = 20/70/10 (the concentration of component C relative to the total amount of component A and component B) : 1.0% by weight), and a multifilament was obtained in the same manner as in Example 1. As in Example 1, Example 7 had good spinning and stretchability, and 100 kg of drawn yarn could be sampled without breakage. Moreover, when the TEM observation of the cross section of the obtained fiber was performed, it took a uniformly dispersed sea-island structure, and the island domain size was 0.02 to 0.25 μm in terms of diameter, as in Example 1. The dispersion diameter of the components was small. Further, when the section of the yarn cross section was alkali etched to dissolve and remove the polylactic acid, the island component was missing, and it was confirmed that the polylactic acid formed the island component. Further, the degree of irregularity of the obtained fiber was 1.6, and the fiber physical properties were also good. The obtained multifilament had a yarn cutting rotational speed of 193 times according to the wear test, and showed the same level of wear resistance as Example 1.

  Further, when the taffeta was prepared and evaluated using the multifilament, both the soft feeling and the glossiness were at the same level as in Example 1. Also, the iron heat resistance test at 170 ° C. showed excellent characteristics as in Example 1.

Example 8
The blend ratio of P1 / component B / P3 (polycarbodiimide “LA-1”: 10% by weight) was 29.5 / 70 / 0.5 (the concentration of component C with respect to the total amount of component A and component B: 0.05) A multifilament was obtained in the same manner as in Example 6 except that the weight%) was used. In Example 8, as in Example 6, both spinning and drawing were good, and 100 kg of drawn yarn could be sampled without breakage. The other characteristics were almost the same as in Example 6. Furthermore, the yarn cutting rotation number by the abrasion test was 170 times, which was a level with no practical problem.

Example 9
A multifilament was prepared in the same manner as in Example 6 except that the blend ratio of P1 / component B / P3 was changed to 0/70/30 (concentration of component C with respect to the total amount of component A and component B: 3.1 wt%). Obtained. In Example 9, the thinning of the yarn was somewhat unstable during spinning, and the thinning deformation point tended to move up and down. In addition, three yarn breaks occurred in 100 kg sampling. The obtained drawn yarn also had a slightly low yarn unevenness U% of 1.9%, but it was at a usable level if the application was limited. The other physical properties of the yarn were slightly inferior to those of Example 1 and Example 6. However, the number of yarn cutting rotations by the abrasion test was 211, and high abrasion resistance was exhibited as in Example 1.

Example 10
A multifilament was prepared in the same manner as in Example 6 except that the blend ratio of P1 / component B / P3 was 0/50/50 (concentration of component C with respect to the total amount of component A and component B: 5.3 wt%). Obtained. In Example 10, at the time of spinning, the thinning of the yarn became more unstable than in Example 9, and the thinning deformation point tended to move greatly up and down. In addition, 30 yarn breaks occurred in 100 kg sampling. The obtained drawn yarn also had a yarn spot U% as bad as 4.8%, and the fiber physical properties were inferior to those of Example 9. Further, the number of rotations of yarn cutting by the abrasion test was 48, which was superior to that of the polylactic acid single yarn (Comparative Example 2), but the use was considerably limited.

1 is a schematic view of a preferred spinning apparatus for producing the fiber of the present invention. It is the schematic which shows a preferable extending | stretching apparatus in order to manufacture the fiber of this invention.

Explanation of symbols

1: Spinning hopper 2: Twin screw extrusion kneader 3: Spinning block 4: Spinning pack 5: Spinneret 6: Monomer suction device 7: Uniflow cooling device 8: Yarn 9: Oil supply device 10: First take-up roll 11: First Two take-up rolls 12: Winding machine 13: Winding yarn (cheese package)
14: Winding yarn (cheese package)
15: Supply roll 16: First hot roll 17: Second hot roll 18: Cold roll 19: Ring rail 20: Winding yarn (pan)

Claims (9)

Synthetic fibers comprising an aliphatic polyester resin (A), a thermoplastic polyamide resin (B), and a polymer alloy containing a compound (C) selected from the following (1), (2) and mixtures thereof The aliphatic polyester resin (A) forms an island component, and the thermoplastic polyamide resin (B) forms a sea component. The island component has a domain size of 0.001 to 3 μm. A synthetic fiber characterized by being.
(1) Compound containing two or more active hydrogen reactive groups in one molecule
(2) Polyalkylene ether glycol having a molecular weight of 400 to 20,000 The synthetic fiber according to claim 1, wherein the aliphatic polyester resin (A) is a crystalline resin and has a melting point of 150 to 230 ° C. The synthetic fiber according to claim 1 or 2, wherein the thermoplastic polyamide resin (B) is a crystalline resin and has a melting point of 150 to 250 ° C. The synthesis according to any one of claims 1 to 3, wherein a blend ratio (weight ratio) of the aliphatic polyester resin (A) and the thermoplastic polyamide resin (B) is 5/95 to 55/45. fiber. Compound (C) is a compound having an active hydrogen reactive group, the active hydrogen reactive groups, one and a plurality of reactive groups of a glycidyl group and / or an oxazoline group and / or carbodiimide groups and / or acid anhydride The synthetic fiber according to any one of claims 1 to 4, wherein In thermogravimetric measurement, when the temperature is increased from room temperature to 250 ° C. at a rate of temperature increase of 10 ° C./min, the thermal weight loss rate at the 200 ° C. reaching point of the compound (C) is 3% or less. Item 6. The synthetic fiber according to any one of Items 1 to 5 . The content of the compound (C) with respect to the total amount of the aliphatic polyester resin (A), the thermoplastic polyamide resin (B) and the compound (C) is 0.005 to 5% by weight. 6. The synthetic fiber according to any one of 6 above. A fiber structure comprising at least a portion of the synthetic fiber according to any one of claims 1 to 7 . The fiber structure according to claim 8 , wherein the fiber structure is a carpet for automobile interior.

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