JP4872339B2 - Core-sheath type composite fiber, crimped yarn, and fiber structure using them - Google Patents

Description

  The present invention provides a core having a very good wear resistance, the core component comprising a polymer alloy in which an aliphatic polyester resin and a thermoplastic polyamide resin are uniformly blended, and a thermoplastic polyamide resin as a sheath component on the fiber surface. The present invention relates to a sheath type composite fiber.

  Recently, with the increasing awareness of the environment on a global scale, the development of non-petroleum-derived fiber materials is eagerly desired. Since conventional general-purpose plastics use petroleum resources as the main raw material, global warming caused by petroleum resources being depleted in the future and mass consumption of petroleum resources has been taken up as major problems.

  By using plant resources that grow by taking in carbon dioxide from the atmosphere as a raw material, 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. For this reason, in recent years, attention has been focused on plastics starting from plant resources, that is, plastics using biomass, and research and development of various plastics and fibers such as aliphatic polyesters have been activated. Among the plastics derived from biomass, attention is particularly focused on plastics that are decomposed by microorganisms, that is, fibers using biodegradable plastics.

  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. However, in recent years, polylactic acid using lactic acid obtained by starch fermentation as a raw material has attracted attention as a biomass-based plastic having relatively high mechanical properties and heat resistance and relatively low production cost.

  Aliphatic polyester resins typified by polylactic acid have been used for a long time in the medical field as, for example, surgical sutures, but they are still more expensive than petroleum-derived general-purpose plastics, and the biodegradability of aliphatic polyester resins The reality is that it has been applied only to a very small amount of applications, making use of such features as well as cost. Recently, however, it has become possible to compete with other general-purpose plastics in terms of price due to improvements in mass production technology.

  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. By applying aliphatic polyester resins typified by polylactic acid as much as possible to the above large-scale applications, and replacing petroleum-derived materials with non-petroleum-derived materials, the problem of petroleum resource depletion and global warming can be solved. May be relieved.

  However, when adapting to clothing and industrial material applications, aliphatic polyesters, especially polylactic acid, have a large problem that they are low in wear resistance and poor in durability, and are less likely to be crimped to be low in quality. .

  For example, when a polylactic acid fiber having low wear resistance is used for clothing, color transfer easily occurs due to rubbing or the like, and in severe cases, the fiber becomes fibrillated and the white blurring quality is remarkably lowered. In addition, it has been found that problems such as excessive irritation to the skin are likely to occur, and the practical durability is poor.

  In addition, when used for carpets for automobile interiors that are subjected to particularly strong rubbing, polylactic acid is easily scraped, and in severe cases, holes may be formed. Furthermore, the property of being easily hydrolyzed, which is a characteristic of aliphatic polyester (especially polylactic acid), on the contrary, becomes a weak point, and the fibrillation and abrasion as described above tend to deteriorate with time. This means that the product life is short, which is a fatal defect in product development.

  On the other hand, aliphatic polyester (especially polylactic acid) fibers tend to be low crimped and easily crimped as crimped yarns such as false twisted yarns and air stuffer crimped yarns. Low). For this reason, for example, when used as a fiber structure such as a carpet for an automobile, only a product without volume feeling can be obtained, and only a product that is clearly inferior to a product made of a conventional synthetic fiber is obtained. It was. The reason why the aliphatic polyester (particularly polylactic acid) fiber is inferior in crimp development is because it is extremely poor in crystallinity as compared with conventional petroleum-derived polymers. For this reason, when crimping the polylactic acid fiber, adopting conditions such as high-temperature heat treatment and high-relaxation treatment in order to develop high crimp, fusion between single yarns and strength reduction may occur. , Have a problem that will not be practical.

  From the above, in order to develop aliphatic polyester (especially polylactic acid) fibers for large-scale applications, it is desired to dramatically improve the wear resistance and crimp characteristics.

  For example, as a method for improving the wear resistance, polylactic acid fibers in which wear is suppressed by adding a lubricant such as fatty acid bisamide to lower the friction coefficient of the fiber surface are disclosed (Patent Documents 1 to 4). reference).

  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.

  On the other hand, an aliphatic polyester fiber having improved abrasion resistance by disposing polyamide having high abrasion resistance as a sheath component has been disclosed (Patent Document 5). Certainly, by having a sheath component with a specific thickness, the wear resistance can be drastically improved, but the affinity between the aliphatic polyester and polyamide is low, so the adhesion at the core-sheath composite interface is insufficient. This is a technique that easily causes sheath cracks. Once the sheath cracks occurred, the polylactic acid that had been exposed was scraped off and the wear resistance was likely to deteriorate. Further, it has been found that when this fiber is crimped and dyed, thermal shrinkage of the fiber occurs in each step, and sheath cracking occurs due to the difference in shrinkage between the sheath component and the core component. For this reason, not only the crimped yarn cannot sufficiently exhibit the wear resistance, but also it is easily blurred and low in quality.

  Furthermore, a technique for improving the mechanical properties of a resin composition by blending polyamide and aliphatic polyester is disclosed (Patent Document 6). According to the method described in Patent Document 6, mechanical properties such as strength, heat resistance, and wear resistance are improved by the reinforcing effect of the polyamide, but in this method, the blend ratio of the polyamide is 5 to 40% and a small amount of components. For this reason, it has been found that the aliphatic polyester easily forms a sea component, and the aliphatic polyester on the fiber surface is easily destroyed, so that the effect of improving wear resistance is not so high.

  In addition, a technique is disclosed in which a polyester is blended with polyamide and a high elongation polyamide fiber is obtained by suppressing dimensional change due to swelling of the polyamide (Patent Document 7). Since the fiber obtained by the method described in Patent Document 7 forms a sea component of polyamide, a polylactic acid fiber with improved wear resistance can be obtained. However, it has been found that aliphatic polyesters and polyamides are incompatible and the interfacial adhesion of these phases is so low that they easily fibrillate and cause whitening. And as for this fiber, the aliphatic polyester which is an island component is partially exposed to the fiber surface, and when the exposed aliphatic polyester and polyamide are peeled off, it is easy to progress the shaving of the whole fiber starting from there. The wear resistance of polyamide was not fully utilized.

In the techniques described in Patent Documents 6 and 7, since the aliphatic polyester is exposed on the fiber surface, when the fiber comes into contact with a high-temperature heat source during the crimping process, the aliphatic polyester is fused, and the process passability is improved. There was a demerit that it deteriorated significantly. Even if the crimped yarn has a high degree of crimp, the crimp is easy to loosen, and there is a problem that durability is inferior particularly in applications where a high external force is applied over a long period of time.
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 2004-36035 A (Claims) JP 2003-238775 A (page 3) JP 2005-206961 A (Claims)

  An object of the present invention is to solve the above-mentioned problems, and to provide an aliphatic polyester fiber that provides a fiber structure excellent in wear resistance and crimping properties, and having high quality and durability, and a fiber structure comprising the same. To do.

  As a result of the present inventors diligently studying to solve the above-mentioned problems, by using a core-sheath type composite fiber having a specific cross-sectional structure, the wear resistance of the aliphatic polyester fiber can be remarkably improved, and the core sheath The present inventors have found that the crimp characteristics of the mold composite fiber can be improved and have completed the present invention.

That is, the present invention provides a core component and an aliphatic polyester resin (A), the comprises a polymer alloy of a thermoplastic polyamide resin (B), Ri sheath component name contains a thermoplastic polyamide resin (C), the core Ru fiber structure der, wherein the alloy structure of the components of the polymer alloy is at least partially including core-sheath type composite fibers and satisfies the (1) to (3) below, and the fibers .
(1) The aliphatic polyester resin (A) forms an island component
(2) The thermoplastic polyamide resin (B) forms a sea component
(3) The diameter of the island component is 0.001 to 2 μm.

  According to the present invention, a fiber having significantly improved wear resistance and a fiber structure comprising the same can be obtained. In addition, the fibers are highly crimped and can be made into crimped yarns that are difficult to crimp. Therefore, the fibers are suitable for general clothing and industrial materials. Thus, it is possible to provide a core-sheath composite fiber, a crimped yarn, and a fiber structure using the core-sheath composite fiber, which are suitably used for applications requiring extremely high wear resistance.

  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 to 230 degreeC. The aliphatic polyester resin (A) used in the present invention has crystallinity that the differential calorific value obtained by differential scanning calorimetry (DSC) measurement at a heating rate of 16 ° C./min of the aliphatic polyester resin (A). When the curve has an endothermic peak and the heat capacity of the melting peak is 10 J / g or more, it is defined as having crystallinity. Since it is so preferable that crystallinity is high, it is more preferable that it is 20 J / g or more, and it is further more preferable that it is 30 J / g or more. It is preferable that the aliphatic polyester resin (A) used in the present invention has crystallinity, so that the crystallinity of the core-sheath composite fiber is increased and the wear resistance and heat resistance are excellent.

  Examples of the aliphatic polyester resin (A) used in the present invention include polylactic acid, polyhydroxybutyrate, polybutylene succinate, polyglycolic acid, and polycaprolactone. Among these, since the raw material is derived from plants, the carbon contained in the resin is originally derived from carbon dioxide present in the atmosphere, and even if carbon dioxide generated during combustion is released to the atmosphere, it is difficult to cause adverse effects of global warming. 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 also composed of poly-D lactic acid consisting only of D-form (D-lactic acid) and L-form (L-lactic acid) alone. And polylactic acid containing both D-lactic acid and L-lactic acid. In the present invention, poly-D lactic acid is defined as polylactic acid comprising 80% by weight or more of D-lactic acid, and poly-L lactic acid is defined as polylactic acid comprising 80% by weight or more of L-lactic acid. . Weight fraction of D-lactic acid contained in poly-L lactic acid (hereinafter sometimes simply referred to as D-form fraction), Weight fraction of L-lactic acid contained in poly-D lactic acid (hereinafter simply referred to as L-form fraction) Is high), the crystallinity of poly-L lactic acid and poly-D lactic acid tends to be low, and the melting point tends to decrease. Since the melting point is preferably 150 ° C. or higher in order to maintain the heat resistance of the fiber, the D fraction in poly-L lactic acid is preferably 10% by weight or less, and preferably 5% by weight or less. It is preferable that it is 3 weight% or less. For the same reason, the L-form fraction in poly-D lactic acid is preferably 10% by weight or less, preferably 5% by weight or less, and preferably 3% by weight or less.

  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, the component A refers to a mixture of poly L lactic acid and poly D lactic acid, and the blend ratio of 40/60 to 60/40 is best because the ratio of stereocomplex crystals can be increased.

  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.

  Component A may be a copolymer of components other than lactic acid, for example, 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. Component A may further contain additives such as particles, crystal nucleating agents, flame retardants, plasticizers, antistatic agents, antioxidants, and ultraviolet absorbers as modifiers.

  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 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 production method of polylactic acid preferably used for component A of the present invention is not particularly limited, but specifically, 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 (Japanese Patent Laid-Open No. 6-65360). And a method in which at least two homopolymers are copolymerized and transesterified in the presence of a polymerization catalyst (see JP-A-7-173266). An indirect polymerization method (see U.S. Pat. No. 2,703,316) in which ring-opening polymerization is carried out after the formation of the polymer is mentioned.

  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 polycapramide (nylon 6), Polyhexamethylene adipamide (nylon 66), polyundecanamide (nylon 11), polydodecanamide (nylon 12), polyhexamethylene sebamide (nylon 610), polypentamethylene sebamide (nylon 510), etc. Can be mentioned.

  When component A is polylactic acid, in order to increase the compatibility, the cohesiveness between the molecular chains of component B may be lowered, that is, the methylene chain length may be increased. Nylon 12, nylon 610, and nylon 510 are also preferably used, and among these, nylon 610 and nylon 510 containing non-petroleum-derived sebacic acid as a monomer are preferably used in terms of providing an environmental load reducing material. Component B may be a homopolymer or a copolymer.

  Component B preferably has a melting point of 150 ° C. or higher and 250 ° C. or lower. In general, when an aliphatic polyester has a melting point, the melting point is usually not higher than 200 ° C., and thus it cannot be said that the heat resistance is high. The melting point of component B to be blended is preferably 250 ° C. or lower. More preferably, the melting point of Component B is 225 ° C. or lower. On the other hand, considering the heat resistance of the fiber or fastness such as crimping or dyeing, the lower limit of the melting point of Component B is preferably 150 ° C. or higher. More preferably, the melting point of component B is 175 ° C. or higher. Component B may be a copolymer as described above, but the higher the crystallinity of the core-sheath composite fiber, the better the wear resistance and heat resistance. Is preferable.

  The fact that the thermoplastic polyamide resin (B) used in the present invention has crystallinity means that the differential heat value obtained by differential scanning calorimetry (DSC) measurement of the thermoplastic polyamide resin (B) at a heating rate of 16 ° C./min. When the curve has an endothermic peak and the heat capacity of the melting peak is 10 J / g or more, it is defined as having crystallinity. Since it is so preferable that crystallinity is high, it is more preferable that it is 20 J / g or more, and it is further more preferable that it is 30 J / g or more.

  The melting point of component B is in the above range, and the higher the crystallinity, the better the abrasion resistance, heat resistance, and crimp elongation after boiling water treatment of the fiber of the present invention. Nylon 6 (melting point 225 ° C.), nylon 610 (melting point 225 ° C.), nylon 510 (melting point 218 ° C.), nylon 11 (melting point 185 ° C.), and nylon 12 (melting point 180 ° C.) are preferred. Nylon 6 is most preferable because it not only has higher crystallinity and wear resistance, but also is inexpensive and is not restricted by applications and can be used widely and widely.

  Component B may contain additives such as particles, flame retardants, antistatic agents and the like.

  The thermoplastic polyamide (C) 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 polycapramide (nylon 6), Polyhexamethylene adipamide (nylon 66), polyundecanamide (nylon 11), polydodecanamide (nylon 12), polyhexamethylene sebamide (nylon 610), polypentamethylene sebamide (nylon 510), etc. Can be mentioned. Further, nylon 610 and nylon 510 using non-petroleum-derived sebacic acid as a monomer are also preferably used in terms of providing an environmental load reducing material. Component C may be a homopolymer or a copolymer.

  Similarly to the component B, when the deterioration of the aliphatic polyester is suppressed in the production process of the core-sheath conjugate fiber and the fastness such as crimping and dyeing is considered, The melting point of C is preferably 150 ° C. or higher and 250 ° C. or lower. More preferably, they are 175 degreeC or more and 225 degrees C or less.

  As described above, the component C may be a copolymer, but the higher the crystallinity of the core-sheath composite fiber, the more the wear resistance tends to be improved, so that the component C used is crystalline. Is preferred.

The higher the melting point of component C is in the above range and the higher the crystallinity, the better the abrasion resistance, heat resistance, and crimp elongation after boiling water treatment of the fiber of the present invention. Nylon 6 (melting point 225 ° C.), nylon 610 (melting point 225 ° C.), nylon 510 (melting point 218 ° C.), nylon 11 (melting point 185 ° C.), and nylon 12 (melting point 180 ° C.) are preferred. Nylon 6 is the most preferable because it is not only high in crystallinity and wear resistance but also low in price and high in versatility, so that it is not restricted by applications and can be widely applied.
Component C may contain additives such as particles, flame retardants, antistatic agents and lubricants.

Preferably the melt viscosity of component C ([eta] c) is a 10~300Pa · ^{sec -1,} more preferably 20~250Pa · ^{sec -1,} and more preferably a 30~200Pa · ^{sec -1.} Increasing the melt viscosity of component C is preferable because the molecular orientation and crystallinity of the core-sheath composite fiber are increased and the wear resistance is increased. In addition, there is also a merit in the manufacturing method in which the ballast effect derived from the polymer alloy of the core component can be suppressed in the spinning process, and the process passability becomes high. On the other hand, if the melt viscosity of component C is too high, a sheath-sheath composite abnormality may occur in the spinning process and the sheath component cannot be uniformly coated, resulting in variations in the thickness of the sheath component in the fiber cross section and the longitudinal direction of the fiber. Wear resistance may deteriorate. From the above, the melt viscosity of component C is preferably in the above range. In addition, although the detail of the measuring method of melt viscosity (eta) is mentioned later, it means the melt viscosity when measured at the measurement temperature of 240 degreeC and the shear rate of 1216 sec- ¹ .

  The closer the melting points of Component B and Component C are, the more preferable it is to select a spinning temperature at which each polymer is less likely to cause thermal degradation during melt spinning, and the resulting fiber is superior in abrasion resistance. For this reason, the difference in melting point between Component B and Component C is preferably 30 ° C. or less, more preferably 20 ° C. or less, and even more preferably 10 ° C. or less.

  The core-sheath type composite fiber of the present invention is preferably a material having a high content of component A because the higher the content of component A (weight% of component A with respect to the total weight of the fiber), the more environmental load reducing material. It is preferably 20% by weight or more, more preferably 30% by weight or more, and particularly preferably 40% by weight or more. On the other hand, the content of component A is preferably 80% by weight or less, more preferably 75% by weight or less, in terms of excellent properties such as wear resistance, crimp fastness, or heat resistance. It is particularly preferred that it is 70% by weight or less. The content of component A of the core-sheath type composite fiber (weight% of component A with respect to the total weight of the fiber) can be calculated by the method described in the examples. That is, the difference between the weight of the fiber after eluting only the component A from the core-sheath type composite fiber and the weight of the original core-sheath type composite fiber is regarded as the weight of the component A, and the difference in the weight is regarded as the original core. It is calculated by dividing by the weight of the sheath type composite fiber.

  The core-sheath type composite fiber of the present invention includes a thermoplastic polyamide (C) as a sheath component, and the core component includes a polymer alloy of an aliphatic polyester (A) and a thermoplastic polyamide (B). By taking a so-called sea island or sea-sea structure where A and component B are intertwined, peeling of the interface between the sheath component and the core component (hereinafter sometimes referred to as the core-sheath interface) is suppressed, and resistance This is a fiber having a sufficiently high wear resistance. For this reason, even if the content of the component A of the core-sheath composite fiber is 20% by weight or more as described above, it is preferable because of high wear resistance and heat resistance. Here, it is preferable that the thermoplastic polyamide (B) constituting the core component forms the sea. Furthermore, in order to increase the ratio of the aliphatic polyester (A) in the core component (polymer alloy), it is important to make the melt viscosity of the aliphatic polyester (A) higher than that of the thermoplastic polyamide (B) during melt spinning. It is.

  The blend ratio (weight ratio) of component A and component B constituting the core component of the core-sheath composite fiber of the present invention is preferably component A / component B = 95/5 to 20/80. Having the component B as the core component and the component B existing at least at a part of the core-sheath interface is preferable because adhesion at the core-sheath interface can be improved and interface peeling can be suppressed. In the case of a core-sheath composite fiber, fibrillation tends to occur when peeling occurs at the core-sheath interface. Once fibrillation begins, the wear rate of the fibers increases rapidly. For this reason, it is important to eliminate peeling of the core-sheath interface in order to increase the abrasion resistance of the fiber. The more the component B is contained in the core component, the more preferable it is in the polymer alloy structure (a) or (c) described later, which is preferable in the present invention, and the abrasion resistance of the fiber is excellent. For this reason, it is preferable that the blend ratio of the component B in a core component is high. However, on the other hand, the core-sheath composite fiber of the present invention preferably contains as much plant-derived component A as possible in order to be a material having the ability to reduce the environmental load, that is, the ratio of component B is lowered. It is preferable. In order to satisfy both of the materials having improved adhesion at the core-sheath interface, excellent wear resistance, and low environmental load, the component A / component B is more preferably 80/20 to 25/75. Preferably, it is 70/30 to 30/70, more preferably 60/40 to 35/65.

  The blend ratio (weight ratio) of component A / component B in the core component of the present invention can be calculated from the weight ratio of component A and component B when subjected to melt spinning. However, when the blend ratio (weight ratio) of component A and component B at the time of manufacture is unknown, it can also be calculated simply using the following formula. That is, the core component of the core-sheath-type composite fiber of the present invention may contain component A, component B, and other minor components, but even in this case, the core component is substantially composed of component A and component B. It can be considered that it consists of only two components, and the blend ratio (weight ratio) of component A / component B can be calculated. First, the cross-sectional slice of the core-sheath composite fiber is observed with a transmission electron microscope (TEM) at a magnification of 40,000 times, and the total area (Aa) of the component A and the total area (Ab) of the component B constituting the core component Ask for. The specific gravity of component A was 1.26 and the specific gravity of component B was 1.14, and the calculation was performed using the following formula.

  Component A / Component B = (Aa × 1.26) / (Ab × 1.14).

  Further, when it is difficult to discriminate the boundary line between the sheath component and the core component in the cross section, the cross section is circumscribed with the component A existing in the outermost layer and is similar to the fiber cross section including only the component A inside. Using the figure as the boundary line, the sheath component and the core component were distinguished.

  Further, examples of the polymer alloy structure in the cross section of the single fiber of the core component include the following (a) to (c). In any polymer alloy structure, the component B in the core component and the component C of the sheath component Good wear resistance is exhibited by the effect of interacting with each other. However, among them, the component B of the core component and the component C of the sheath component form a continuous phase, and the core alloy polymer alloy structure is (a) or (c) in that the abrasion resistance is remarkably improved. It is preferable that it is (a).

(A) Component A is an island component, Component B is a sea component (sea-island structure)
(B) Component B is an island component, Component A is a sea component (sea-island structure)
(C) Both component A and component B are sea components (sea-sea structure).

  Here, the sea-island structure in which (a) component A, which is a preferred polymer alloy structure in the present invention, is an island component and component B is a sea component will be described with reference to a TEM photograph of FIG. In FIG. 6, the dyed component represents the thermoplastic polyamide resin (B), and the undyed component represents the aliphatic polyester resin (A). As shown in FIG. 6, a structure in which component A is separated into a plurality of substantially circular regions by component B, which is a continuous region, is (a) a sea-island structure in which component A is an island component and component B is a sea component. Define. In addition, a so-called sea-island lake structure in which component B exists as an island component (substantially circular) inside component A, which is an island component, is also included in the sea-island structure of the present invention. Polymer alloy structure (b) The sea-island structure in which component A is a sea component and component B is an island component is a structure in which component B is divided into a plurality of substantially circular regions by component A, which is a continuous region. Also, the polymer alloy structure (c) of the present invention is the sea-sea structure in which both component A and component B are sea components. Both component A and component B are not substantially circular, and the island component and the sea component cannot be distinguished. Define as structure.

  The polymer alloy structure of the core component is closely related to the blend ratio (weight ratio) of component A and component B described above, and the viscosity ratio between the melt viscosity (ηa) of component A and the melt viscosity (ηb) of component B described later. The alloy structure of the core component can be controlled by setting each to an appropriate range.

In order to obtain the structure (a) which is a particularly preferable polymer alloy structure, it is preferable to increase the melt viscosity ηa of the component A and decrease the melt viscosity ηb of the component B. This is because the polymer alloy structure is affected by the balance of the melt viscosity of component A and component B. A polymer alloy structure is formed when shear deformation is applied in a molten state, but a structure in which the shear stress generated by the shear deformation is lowest is easily formed. This is because the energy level of the entire system is lowered and stable. This means that the sea component, which is a component to which shear is applied directly, is likely to be formed with a component having a low melt viscosity, and conversely, a component with a high melt viscosity is likely to form an island component. That is, in order to obtain a particularly preferred polymer alloy structure (a) in the present invention, the melt viscosity ratio (ηb / ηa) is preferably small, preferably 2 or less, and 1.5 or less. More preferably, it is more preferably 1 or less. However, if the ratio of melt viscosity is too small, the diameter of the island component tends to be coarsened, so the ratio of melt viscosity (ηb / ηa) is preferably 0.10 or more, preferably 0.15 or more. More preferably, it is more preferably 0.20 or more. In addition, although the detail of the measuring method of melt viscosity (eta) is mentioned later, it means the melt viscosity when measured at the measurement temperature of 240 degreeC and the shear rate of 1216 sec- ¹ .

  When the core component of the core-sheath composite fiber of the present invention has a sea-island structure, the island component preferably has a diameter of 0.001 to 2 μm. By setting the upper limit of the diameter of the island component to 2 μm, the area of the interface formed by the component A and the component B is remarkably increased and the abrasion resistance of the fiber is remarkably improved. On the other hand, if the diameter of the island component is too small, component A and component B may become compatible at the molecular level to inhibit crystallinity, and the abrasion resistance, heat resistance, and dyeing fastness of the fiber may decrease. In this respect, the lower limit of the diameter of the island component is preferably 0.001 or more. Therefore, the diameter of the island component is preferably 0.005 to 1 μm, and more preferably 0.01 to 0.8 μm. More preferably, it is 0.02-0.5 micrometer.

  In addition, with the diameter of the island component in the present invention, as described in detail in the examples, the cross-sectional slice of the core-sheath composite fiber is observed with a transmission electron microscope (TEM) (40,000 times), The diameter of the island component was measured for 100 islands per core-sheath type composite fiber sample (assuming the island as a circle, the diameter converted from the area of the island was taken as the diameter of the island component). By setting the diameter distribution of the island component within the above range, the abrasion resistance, heat resistance, and dyeing fastness of the fibers are improved.

  Further, since the material constituting the core component of the core-sheath composite fiber of the present invention is a polymer alloy, unlike a block copolymer in which aliphatic polyester blocks and polyamide blocks are alternately present in one molecular chain, It is important that the group polyester molecular chain (component A) and the polyamide molecular chain (component B) exist substantially independently. The difference in this state is that 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 fell from the melting point of the thermoplastic polyamide resin before blending is observed. 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.

  Thus, since component A and component B exist substantially independently, thermoplastic polyamide resin (C) which forms a sheath component, and thermoplastic polyamide resin (B) which forms a core component mutually This is preferable because it easily causes an action and improves the adhesiveness at the interface between the sheath component and the core component. As a result, the inherent properties of the thermoplastic polyamide resin (C), which is the sheath component, are reflected in the properties of the fibers, and the wear resistance is dramatically improved. Therefore, in the present invention, the melting point drop of the thermoplastic polyamide (B) is preferably 2 ° C. or less.

  Moreover, it is preferable that each of the island components has a strip-like shape in the fiber axis direction. It is preferable that the island component has a streak shape because the area of the composite interface where one island component is bonded to the sea component is increased and fibrillation can be suppressed. In addition, the island component has a merit that the strength is increased by forming elongated stripes. When the island component is in a streak shape, it is most preferable that the island component is completely parallel to the fiber axis direction. However, in the present invention, those inclined at 5 ° or less from the fiber axis are elongated in a streak shape in the fiber axis direction. It is defined as

  The core-sheath composite fiber of the present invention needs to have thermoplastic polyamide (C) as a sheath component. Having the thermoplastic polyamide (C) as the sheath component is preferable because the surface of the fiber is substantially formed only of the polyamide, and the wear resistance is remarkably increased. Further, as described above, the core-sheath type composite fiber of the present invention contains the thermoplastic polyamide (B) having a chemical structure close to that of the sheath component, that is, high affinity, in the core component, so that it is processed or dyed, or It is preferable because the sheath is not cracked by rubbing when the product is used and has excellent wear resistance.

  In particular, the component B and the component C are preferably polyamides mainly composed of the same type of monomer from the viewpoint of enhancing the adhesiveness at the interface between the sheath component and the core component. For example, when Component B is a copolymer of nylon 6, Component C is preferably a copolymer of nylon 6 or a homopolymer of nylon 6.

  From the viewpoint of excellent wear resistance of the core-sheath composite fiber of the present invention, the thickness of the sheath component is preferably 0.4 μm or more. Increasing the thickness of the sheath component is preferable because the fiber has excellent wear resistance. In addition, in the spinning process, there is also a merit in the manufacturing method that the ballus effect derived from the polymer alloy of the core component can be suppressed and the process passability becomes high. From the above, the thickness of the sheath component is preferably 0.4 μm or more, more preferably 0.7 μm or more, and even more preferably 1 μm or more. When the sheath thickness is too thick, the ratio of the sheath component to the entire fiber is increased, and the ratio of component A to the total fiber weight is decreased. May fall off. For this reason, the thickness of the sheath component is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less.

  The core-sheath type composite fiber of the present invention is a fiber having excellent abrasion resistance, and the fiber surface is substantially composed of a sheath component in all longitudinal directions, and in particular, component A is exposed on the fiber surface. Preferably not. By substantially covering the fiber surface with the sheath component, the wear resistance is drastically improved. Here, the fiber surface is substantially covered with the sheath component. When the cross section of the fiber is observed by the method described in the embodiment, the sheath component with a thickness of 0.1 μm or more is coated on the entire cross section. Means that It is preferable that the melt viscosity of the component C and the thickness of the sheath component are within the above ranges in that the component A is easily exposed to the core-sheath composite fiber not exposed on the fiber surface in all the longitudinal directions.

  In the core-sheath type composite fiber of the present invention, the total heat capacity of the melting peak of the differential calorimetric curve measured at a heating rate of 16 ° C./min is preferably 50 J / g or more, more preferably 55 J / g or more, More preferably, it is 60 J / g or more, particularly preferably 65 J / g or more, and most preferably 70 J / g or more. When the total heat capacity of the melting peak is 50 J / g or more, the fiber contains many highly developed crystals, and wear resistance, heat resistance, fastness of dyeing and crimping, etc. are excellent. preferable. In order to show such a melting peak, it is preferable to use highly crystalline polymers as Component A, Component B, and Component C. Further, as described above, it is preferable that the diameter of the island component in the fiber cross section is in the above range. That is, the core-sheath type composite fiber of the present invention comprises an aliphatic polyester (A), a thermoplastic polyamide resin (B), and a thermoplastic polyamide resin (C), and therefore has a large number of composite interfaces formed of different polymers. is doing. Since the polymer crystal has a three-dimensional regular structure in which the same kind of polymer chains are gathered, if the area of the composite interface is too large, the contact frequency between the same kind of polymers may be lowered and the crystallinity may be lowered. For this reason, it is preferable to make the diameter of an island component into the above-mentioned range.

The core-sheath type composite fiber of the present invention preferably contains a lubricant in that it becomes a fiber having more excellent wear resistance. By including a lubricant, the surface frictional resistance of the fiber is lowered and the frictional force is hardly applied to the fiber, so that the wear resistance is improved. As the lubricant of the present invention, the higher the affinity with each of Component A, Component B, and Component C, the more preferable the lubricant is supported on the fiber, and the effect of the lubricant is easily maintained over a long period of time. Further, the higher the heat resistance of the lubricant, the more preferable it is because it does not volatilize in the melt spinning process, is easily carried on the fiber, and can exhibit the effect of the lubricant over a long period of time. From the viewpoints of compatibility with Component A, Component B, and Component C, and heat resistance, the lubricant is preferably a fatty acid bisamide or an alkyl-substituted fatty acid monoamide, and particularly preferably a fatty acid bisamide. The fatty acid bisamide preferred as a lubricant in the present invention refers to a compound having two amide bonds in one molecule such as saturated fatty acid bisamide, unsaturated fatty acid bisamide, aromatic bisamide, etc., for example, methylene biscaprylic acid amide , Methylene biscapric amide, methylene bis lauric acid amide, methylene bis myristic acid amide, methylene bis palmitic acid amide, methylene bis stearic acid amide, methylene bis isostearic acid amide, methylene bisbehenic acid amide, methylene bis oleic acid amide , Methylenebiserucamide, ethylenebiscaprylate, ethylenebiscapricamide, ethylenebislauric acid amide, ethylenebismyristic acid amide, ethylenebispalmitic acid amide, ethylenebisstearic acid amide , Ethylene bisisostearic amide, ethylene bis behenic amide, ethylene bis oleic amide, ethylene bis erucic amide, butylene bis stearic amide, butylene bis behenic amide, butylene bis oleic amide, butylene bis erucer Acid amide, hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bis oleic acid amide, hexamethylene bis erucic acid amide, m-xylylene bis stearic acid amide, m-xylylene bis-12-hydroxy stearin Acid amide, p-xylylene bis stearic acid amide, p-phenylene bis stearic acid amide, p-phenylene bis stearic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacin Acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide, N, N′-distearyl isophthalic acid amide, N, N′-distearyl terephthalic acid amide, methylene bishydroxy Examples include stearic acid amide, ethylene bishydroxystearic acid amide, butylene bishydroxystearic acid amide, hexamethylene bishydroxystearic acid amide, and the like.
In addition, the alkyl-substituted fatty acid monoamide used as a preferable lubricant in the present invention refers to a compound having a structure in which an amide hydrogen such as a saturated fatty acid monoamide or an unsaturated fatty acid monoamide is replaced with an alkyl group, such as N-lauryl lauric acid amide. N-palmityl palmitic acid amide, N-stearyl stearic acid amide, N-behenyl behenic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid amide etc. are mentioned. The alkyl group may have a substituent such as a hydroxyl group introduced into its structure. For example, methylol stearamide, methylol behenic acid amide, N-stearyl-12-hydroxystearic acid amide, N- Oleyl 12 hydroxystearic acid amide and the like are also included in the alkyl-substituted fatty acid monoamide of the present invention.

  The fiber in the present invention refers to a thin and long shape, and it is a multifilament in which a filament yarn is formed by twisting several to several tens of filaments even if it is a generally-known long fiber (filament). Or short fibers (staples), or short fibers used for electric flocking processing, i.e., piles, and there are no particular restrictions as long as they are recognized as having these fiber shapes. However, a multifilament is preferable because it is easy to utilize the wear resistance which is an effect of the present invention.

  In addition, there is no particular limitation on the form of fibers such as raw yarn, twisted yarn, and processed yarn, but by having a bulky property, the external force applied to the fibers is easily dispersed in each single fiber, and exhibits excellent wear resistance. Therefore, a crimped yarn is preferable.

  As the crimped form of the crimped yarn, for example, an air stuffer crimped yarn having a random loop-like crimped form expressed by the turbulent flow of the heating fluid inside the crimp nozzle, or forcedly placed in the stuffing box Such as a mechanical crimped yarn having a zigzag crimp formed by pressing, a three-dimensional spiral crimped yarn having a coiled crimped shape, a false twisted yarn, a knit denit crimped yarn, etc. Examples of the crimped yarn having a known crimped form include air stuffer crimped yarn and false twisted yarn because they have high bulkiness, do not contain excessively bent single fibers, and have excellent wear resistance. The air stuffer crimped yarn is particularly preferable.

  The air stuffer crimped yarn, which is a preferred crimped yarn of the present invention, will be described with reference to the explanatory photographs in FIGS. Fig. 4 is a photograph of the air stuffer compressed yarn placed on black paper in a multifilament state and observed from the side. Fig. 5 shows the air stuffer compressed yarn separated into single yarns and placed on black paper. It is the photograph observed from the side. As can be seen from FIGS. 4 and 5, the air stuffer crimped yarn has a crimped form in which the single yarns constituting the multifilament each have a random loop shape and appropriate entanglement exists between the single yarns. For this reason, it is preferable because the bulkiness is high and it is easy to maintain the bulkiness for a long period of time. When the core-sheath type composite fiber of the present invention is an air stuffer crimped yarn, it does not have an excessively bent portion, and becomes a multifilament that is a bulky, so that the external force is dispersed in each single yarn and particularly wear-resistant It is excellent in performance.

  It is preferable that the bulky property of the crimped yarn is high in that it is more excellent in wear resistance than the core-sheath type composite fiber of the present invention. Specifically, the crimp elongation after boiling water treatment, which is an index of bulkiness, is preferably high, preferably 5% or more, more preferably 10% or more, and particularly preferably 15% or more. The upper limit of the crimp elongation after the boiling water treatment is not particularly limited, but if it is too high, the wear resistance deteriorates due to the difference in strain between the two polymers at the interface between the core component and the sheath component. In order to suppress defects, the elongation after boiling water treatment is preferably 35% or less, more preferably 33% or less, and particularly preferably 30% or less.

  When the core-sheath type composite fiber of the present invention is a crimped yarn, it is difficult to crimp in a dyeing process, a high-order processing process, or a long-term use after forming a fiber structure (high crimp fastness). ) As a result, the crimp elongation after the boiling water treatment under the load of 2 mg / dtex (hereinafter referred to as the crimp elongation after the boiling water treatment under the load of 2 mg / dtex) in that excellent wear resistance is easily exhibited. The rate may be simply described as “elongation rate under restraint load”) is preferably 3% or more. More preferably, it is 5% or more, still more preferably 7% or more, and particularly preferably 10% or more. The upper limit is not particularly limited, but it is preferably 30% or less from the standpoint of suppressing adverse effects such as tightening when cheese dyeing is performed, and the occurrence of staining shading on the end face of the package.

  As the core-sheath type composite fiber of the present invention is superior in mechanical properties, it has better process passability when made into a fiber product, and the strength is preferably 1.5 cN / dtex or more, and 1.8 cN / dtex or more. More preferably, it is 2 cN / dtex or more. A higher strength is preferable because a fiber structure having a higher product strength can be obtained. However, when the core-sheath composite fiber of the present invention is a crimped yarn, if the strength is too high, the stiffness of the fiber becomes excessively high, and rubbing occurs. When receiving the stress, the stress may concentrate on the bent portion, and the wear resistance may decrease. For this reason, the strength is preferably 4 cN / dtex or less, more preferably 3.8 cN / dtex or less, and particularly preferably 3.5 cN / dtex or less. The core-sheath type synthetic fiber having such strength can be produced by a melt spinning method and a drawing method described later.

  Moreover, the ductility | elongation of the core-sheath-type composite fiber of this invention is 15 to 70%, since the process passability at the time of making a textile product is favorable, it is preferable. The core-sheath type synthetic fiber having such elongation can be produced by a melt spinning method and a drawing method described later. More preferably, it is 20-60%, More preferably, it is 30-50%.

  Further, if the boiling water shrinkage is 0 to 20%, the dimensional stability of the fiber and the fiber product is good, which is preferable. More preferably, it is 3-15%, More preferably, it is 5-10%.

  In the core-sheath conjugate fiber of the present invention, the thicker the single yarn fineness is, the easier it is to increase the thickness of the sheath component and the better the abrasion resistance. On the other hand, if the single yarn fineness is too thick, the stiffness of the fiber becomes excessively high and the quality is inferior, and the discharged polymer is not sufficiently cooled in the spinning process, resulting in a coarse island component diameter. It may become. For this reason, the single yarn fineness is preferably 0.1 to 100 dtex, more preferably 1 to 50 dtex, and particularly preferably 2 to 30 dtex.

  The yarn spot of the core-sheath type composite fiber of the present invention is preferably small. It is preferable to make the yarn unevenness small because it is possible to prevent local wear from invading when scratched and the wear resistance is excellent. For this reason, the thread spot (Uster) (U%) (Normal) which is an index of the thread spot is preferably 2% or less, more preferably 1.5% or less. More preferably, it is 1% or less, and particularly preferably 0.5% or less. With conventional simple polymer alloy fibers of aliphatic polyester and polyamide, so-called ballast occurs in the vicinity of the discharge hole in melt spinning, and there is a case where the quality deteriorates due to thickening in the thinning deformation process. Since the core-sheath type composite fiber of the invention has a sheath component on the surface of the fiber, the ballast is suppressed, the thinning behavior is extremely stabilized, the yarn unevenness is small, and the wear resistance is excellent.

  The cross-sectional shape of the core-sheath type composite fiber of the present invention can take a wide variety of cross-sectional shapes such as a round shape, a Y shape, a multileaf shape, a polygonal shape, a flat shape, and a hollow shape. Moreover, when it is a multifilament, the cross-sectional shape of each filament may be the same, or may differ.

  FIG. 7 illustrates the core-sheath composite fiber of the present invention. The cross-sectional shape of the core component of the core-sheath composite fiber is also arbitrary, but the adhesion at the core-sheath interface increases, and the ratio of the core component of the core-sheath composite fiber, that is, the content of component A is high. The cross-sectional shape of the core component is preferably similar to the cross-sectional shape of the fiber in that the fiber is excellent in abrasion. Of course, the core-sheath composite fiber of the present invention is not limited to the cross-sectional shape of FIG. The number of core components of the core-sheath type composite fiber of the present invention is arbitrary, and one filament may have one core component inside or may have a plurality of core components. good. Of course, the center of gravity of the cross section of the fiber and the center of gravity of the cross section of the core component may be the same or different, but the more the fiber surface is uniformly coated with the sheath component, the better the wear resistance. The center of gravity of the surface and the center of gravity of the cross section of the core component are preferably the same. In the multifilament, the cross-sectional shape of the core component and the number of core components of each filament may be the same or different.

  In the case of the air stuffer crimped yarn preferred in the present invention, the higher the bulky property of the crimped yarn, the better the wear resistance. Therefore, the cross-sectional shape is preferably an irregular sectional shape that is not round. In addition, it is preferable to have an irregular cross section because the cooling effect of the yarn is increased in the spinning process and the island component can be uniformly refined because high stress is applied. Furthermore, it is preferable to adopt a modified cross section because the surface area of the fiber is increased, the heating efficiency at the time of crimping is increased, the crimp is easily set, and the fastness of crimp is excellent. Specifically, Y-type, multi-leaf type, and flat type are preferable, and Y-type and flat type are particularly preferable.

  In the case where the core-sheath composite fiber of the present invention has an irregular cross section, the higher the degree of irregularity, the better the abrasion resistance and the fastness of crimping. The degree of irregularity is preferably 1.3 or more, more preferably 1.5 or more, still more preferably 1.8 or more, and particularly preferably 2 or more. The upper limit is not particularly limited, but if the degree of irregularity is too high, the cross-sectional shape is likely to change due to external force and the glossiness of the fiber is likely to change, so the degree of irregularity is 8 or less. Is preferably 7.7 or less, more preferably 7.5 or less, and particularly preferably 7.2 or less.

  The profile of the present invention is defined as a ratio (D1 / D2) of the diameter D1 of the circumscribed circle and the diameter D2 of the inscribed circle when the cross section of the single fiber is observed by TEM. When it is judged that the irregular cross section generally retains line symmetry and point symmetry, the inscribed circle is a circle inscribed in the curved line that forms the profile of the irregular cross section fiber in the single fiber cross section, and the circumscribed circle is a single fiber. It is a circle that circumscribes a curve that defines the profile of the irregular cross-section fiber in the cross section. When it is judged that the irregular cross section has a shape that does not retain line symmetry or point symmetry, it is inscribed at least at two points with the curve that forms the contour of the irregular cross section fiber, and exists only inside the fiber. A circle having the maximum radius that can be taken in a range where the circumference of the tangent circle does not intersect with the curve forming the contour of the irregular cross-section fiber is defined as an inscribed circle. The circumscribed circle circumscribes at least two points in the curve showing the profile of the irregular cross-section fiber, exists only outside the cross-section of the single fiber, and is the smallest possible in the range where the circumference of the circumscribed circle and the profile of the irregular cross-section fiber do not intersect A circle having a radius is defined as a circumscribed circle. In the calculation of the irregularity, the irregularities were calculated and averaged at 10 cross sections obtained by cutting different locations.

  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, regenerated fiber, semi-synthetic fiber, synthetic fiber, twisted yarn, or 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 a use of the fiber structure using the fiber of the present invention, clothing that requires wear resistance, for example, sportswear such as outdoor wear, golf wear, athletic wear, ski wear, snowboard wear, and 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 a long period 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 use suitably also for the interior material for motor vehicles. 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.

  Here, the carpet for automobiles, which is a preferred use of the fiber structure in the present invention, is not limited in its processing form. For example, woven carpets such as Danten, Wilton, Double Face, Axisminster, etc., tufting Use embroidery carpets such as hook drags, bonded carpets such as bonded, electrodeposited, and cords, knitted carpets such as knit and russell, carpets with piles typified by compression carpets such as needle punches, or combinations thereof be able to. In order to obtain a carpet with a high volume feeling at a lower cost, a tough structure consisting of at least a surface yarn that is a pile fiber yarn, a base fabric to which the surface yarn is tufted, and a backing material attached to the back of the base fabric. A ting carpet is preferred.

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

That is, while separately measuring an aliphatic polyester resin (component A) such as poly-L-lactic acid and a thermoplastic polyamide resin (component B) such as nylon 6, the melting point of component B (Tmb) to the melting point of component B (Tmb) +40 A polymer alloy is produced by kneading at 2 ° C. using a twin screw extruder or a single screw extruder. At this time, since the diameter of the island component can be easily controlled, it is preferable to use a biaxial extrusion kneader. As a method for controlling the polymer alloy structure and the diameter of the island component, the blend ratio and melt viscosity ratio of the two components (component A and component B) are adjusted in the above-described range, and the shear rate is 200 to 20,000 sec ^{−. 1} and can be controlled by kneading in a range of residence time of 0.5 to 30 minutes. In particular, as a method for reducing the diameter of the island component, it is preferable that the kneading temperature is lower in the above range, the shear rate is higher, and the residence time is shorter. The polymer alloy resin comprising the component A and the component B constituting the fiber core component is an extrusion attached to the spinning machine, even if it is used after being dried after being prepared in an extrusion kneader different from the spinning machine. You may adjust continuously at the time of spinning with a kneader. In the case of using it in advance, all the polymer alloys used for the core component may be pre-adjusted chips. A master chip prepared by kneading component A or component B at a high concentration is prepared. Component A and / or component B may be used in a chip blend. Since component A and component B can be more uniformly dispersed and thermal deterioration of component A can be easily suppressed, component A and component can be mixed with a single-screw kneader and / or a twin-screw extruder kneader attached to a spinning machine. It is preferable to use a method in which the polymer alloy of B is continuously adjusted and supplied to the spin pack.

  The polymer alloy resin composed of the components A and B is used as a core component, and a thermoplastic polyamide resin (component C) such as nylon 6 is used as a sheath component, and fiberized by a melt spinning method. The core component and the sheath component are melted in separate extrusion kneaders, weighed with separate gear pumps, merged with the spinneret inside the spin pack, and discharged. At this time, the island component (component A) is re-agglomerated. In order to suppress, the filter layer of the core component includes a high mesh filter layer (# 100 to # 200), a porous metal, a non-woven filter with a small filtration diameter (filtration diameter of 5 to 30 μm), an in-pack blend mixer (static mixer or It is necessary to devise such as incorporating a high mixer.

  The polymer alloy of the aliphatic polyester (component A) and the polyamide (component B) as the core component is incompatible, and the melt exhibits a strong behavior with an elastic term. There is a tendency to make thinning and deformation unstable. The polyamide (component C) which is the sheath component of the present invention has an effect of suppressing ballast, and it is effective to adjust the melt viscosity of the component C and the thickness of the sheath component within the above-described ranges. In order to suppress ballast, the spinning temperature is increased to lower the elongational viscosity, the discharge hole diameter of the spinneret is increased, the discharge linear velocity (the polymer flow rate at the final throttle part of the discharge hole) is decreased, or the discharge is reduced. A method of increasing L / D, which is a ratio of the hole length to the hole diameter, a method of rapidly cooling the discharged yarn, and the like are effective. The discharge hole length in the present invention refers to the length of 43 in the cross-sectional schematic diagram of the base hole shown in FIG. 8, and the length of the portion where the hole shape is kept the same as the shape of the discharge hole. It is a part that controls the flow rate when the polymer is discharged. When the discharge hole is a round hole, the hole diameter refers to the length of 44 in the schematic diagram of the lower surface portion of the base shown in FIG. Further, the slit length and the slit width in the Y hole, the multi-leaf hole, and the flat hole are the length of the slit length of 45 and the slit width of 46 in the schematic view of the lower surface of the base shown in FIG. It points to.

  The core-sheath type composite fiber in the present invention can be obtained by combining a plurality of bases as shown in FIG. 9 and joining the core component and the sheath component at the discharge holes. The discharge linear velocity in the present invention is calculated from the discharge hole area, the total discharge amount, and the number of holes for the die immediately before the polymer discharge of 48 in FIG. When the hole shapes of the spinneret differ from hole to hole, the average value of the discharge areas of all holes was calculated, and the discharge linear velocity was calculated from the following equation using the discharge area of the hole closest to the area.

Discharge linear velocity (m / min) = Q / H / ρ / A / 100
Q: Total discharge rate (g / min)
H: Number of holes ρ: Melt density (g / min)
ρ = 1.08 × content of component A with respect to total fiber weight (wt%) / 100 + 1.00 × (1-content of component A with respect to total weight of fiber (wt%) / 100)
A: Discharge area (cm ² )
For example, when the die hole shape is a Y hole (see FIG. 8), the formula of A (cm ² ) = 3 × slit width (cm) × slit length (cm) + (the middle triangle surrounded by the slit) Although the discharge area can be calculated by the above, if the slit width is negligibly small compared to the slit length, the area of (the middle triangle surrounded by the slit) is ignored and A (cm ² ) = 3 × slit The discharge area may be calculated by the formula of width (cm) × slit length (cm).

  The spinning temperature can be determined by the melting point of component B (polyamide), and the optimum range is the melting point Tmb + 5 ° C. to Tmb + 40 ° C. of component B (for example, 205 to 240 ° C. when the melting point Tmb of component B is 200 ° C.). . Moreover, the discharge linear velocity for suppressing the swelling due to the ball of the spun yarn and stabilizing the thinning and deformation is preferably 1 to 20 m / min, more preferably 2 to 15 m / min, still more 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. In addition, the cooling start position is preferably as the depth of the die surface, which is the distance from the die surface (the distance from the cooling start position to the die surface) is shorter, because the occurrence of ballast in the spun yarn can be suppressed. However, if the die surface depth is too shallow, the die surface cools down and the spun yarn contains unmelted polymer, leading to discharge failure, resulting in low fiber uniformity and strength. is necessary. For this reason, it is preferable that the depth of a nozzle | cap | die surface is 0.01-0.15m, and 0.015-0.1m is more preferable. More preferably, it is 0.02-0.05 m. In addition, a method of actively heating the base surface by arranging a ring heater around the base surface so that the temperature of the base surface does not decrease is also preferable.

  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 5000 m / min. The core-sheath-type composite fiber of the present invention preferably has mechanical properties such as appropriate strength and elongation, and preferably exhibits high crimp when subjected to crimping processing. It is preferable to stretch and heat-treat the oriented fibers so that the elongation of the composite fiber is in the range of 15 to 70%. For example, when the spinning speed is a relatively low spinning speed of 500 to 3000 m / min, the stretching is preferably 1.5 to 6 times, more preferably 2 to 5 times. For example, when the spinning speed is a relatively high spinning speed of 3000 m / min or more, the film is preferably stretched 1.1 to 4 times, more preferably 1.2 to 3 times. The stretching temperature and heat treatment temperature may be appropriately selected depending on the glass transition points and melting points of Component A and Component B, but the stretching temperature can be 20 to 80 ° C and the heat setting temperature can be 100 to 200 ° C.

  Further, when the fiber of the present invention is left in the state of an unstretched fiber, orientation relaxation is likely to occur. If there is a time difference until stretching between unstretched packages, the fiber's strength and heat shrinkage characteristics easily vary. For this reason, the core-sheath type composite fiber of the undrawn yarn that has been spun is taken up with a roll, and then continuously drawn and heat-treated without being wound, that is, a direct spinning drawing method is used in which spinning and drawing are performed in one step. It is preferable to do.

  By crimping the drawn yarn thus obtained, a crimped yarn having a high crimp is obtained. In the case of applying air stuffer crimp, which is a particularly preferable crimp form in the present invention, a crimp applying device that performs normal heating fluid processing may be used. For example, a jet nozzle type, a jet stuffer type In addition, various crimping methods such as a gear system are adopted. In order to achieve high crimping and manifestation thereof, a jet nozzle system is preferable, and for example, a crimp nozzle described in US Pat. No. 3,781,949 is preferably used. The crimped yarn may be appropriately selected according to the intended use, but in order to obtain a crimped yarn having a high crimp elongation rate after boiling water treatment and a high elongation rate under restrained load, the yarn temperature in the crimp nozzle is increased. It is preferable to perform heat treatment in advance with a heat source such as a heat roller or a heat plate before supplying the crimped nozzle. For this reason, the temperature of the heat source before the crimp nozzle is preferably 130 to 220 ° C, more preferably 150 to 210 ° C, and particularly preferably 170 to 200 ° C. Further, for the purpose of fixing the crimp after applying the crimp, a cooling device and further a rotary filter may be combined as described in, for example, Japanese Patent Laid-Open No. 5-321588.

  Further, when the core-sheath composite fiber of the present invention is an air stuffer crimped yarn, if the thermal shrinkage characteristics vary due to orientation relaxation between the packages as in the spinning and drawing processes, the crimping characteristics are longer. Product quality may deteriorate due to variations in direction. For this reason, it is most preferable to perform the three steps of spinning, drawing and crimping in one step.

  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. The measurement conditions are as follows.

GPC equipment: Waters2690
Column: Shodex GPC K-805L (8mmID * 300mmL) Used by linking two. Solvent: Chloroform (Wako, for HPLC)
Temperature: 40 ° C
Flow rate: 1 ml / min Sample concentration: 10 mg / 4 ml
Filtration: Mysholy disk 0.5μ-TOSOH
Injection volume: 200 μl
Detector: Differential refractometer RI (Waters 2410)
Standard: polystyrene (concentration: sample 0.15 mg / solvent 1 ml)
Measurement time: 40 minutes.

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. Relative sulfuric acid relative viscosity of thermoplastic polyamide The relative sulfuric acid viscosity of nylon 6 was measured at 25 ° C. by preparing a 98% sulfuric acid solution of 0.01 g / mL.

D. Polymer melting point Using a differential scanning calorimeter DSC-7 manufactured by Perkin Elmer, 20 mg of the original polymer of the core-sheath composite fiber (component A, component B, component C) was heated to a heating rate of 16 ° C / min. In the differential calorimetric curve obtained by the above measurement, the temperature at which an extreme value was given to the endothermic side was defined as the melting point (° C.), and the peak was determined as the melting peak of the polymer. The crystallinity of the original polymer was judged to have crystallinity when the heat capacity calculated from the area of the melting peak was 10 J / g or more.

  If the original polymer is not available, the fiber has a differential calorimetric curve to determine the melting point of the original polymer. Which component the melting peak of the fiber differential calorimetric curve belongs to was determined by the following method.

  First, using a core-sheath type composite fiber (fiber 1: fiber containing component A, component B, and component C) as a sample, DSC measurement was performed under the same measurement conditions as described above to obtain a differential caloric curve 1.

  Next, the fiber (fiber 2: component after removing component A in the core-sheath type composite fiber (fiber 1) with a solvent (chloroform), washing the obtained fiber with water, and vacuum-drying at room temperature for 24 hours. DSC measurement was carried out under the same conditions as above for a fiber containing B and component C), and a differential calorimetric curve 2 was obtained. Differential calorimetric curves 1 and 2 were compared, and the disappearing melting peak was determined to be the melting peak of component A, and the melting point was determined from differential calorimetric curve 1.

  Next, the component C in the core-sheath type composite fiber (fiber 1) is removed with a solvent (sulfuric acid solution), and the resulting fiber is washed with water and vacuum dried at room temperature for 24 hours (fiber 3). : Fiber containing component A and component B) was subjected to DSC measurement under the same conditions as above to obtain a differential calorimetric curve 3. The melting point of component C was determined by comparing the suggested heat quantity curves 1, 2, and 3. At this time, in order to obtain the fiber 3, the solvent treatment conditions (solvent temperature, immersion time) for substantially removing only the component C (sheath component) were determined in advance. That is, the core-sheath type composite fiber is immersed in a solvent (sulfuric acid solution) at a constant temperature for a fixed time, then taken out, washed with water, and vacuum-dried at room temperature for 24 hours. About this fiber, the fiber side surface is observed with an optical microscope, and it is confirmed whether the sheath component is removed. The above operation was repeated for a plurality of solvent treatment conditions (solvent temperature, immersion time), and solvent treatment conditions for substantially removing only component C (sheath component) were determined in advance.

E. Sum of heat capacities of melting peaks of differential calorific curve of core-sheath type composite fiber Using the core-sheath type composite fiber of the present invention as a sample, a differential calorimetric curve was obtained under the same conditions as in Section D. The peak having an extreme value on the endothermic side present in the differential calorific value curve was judged as a melting peak, and the heat capacities determined from the areas of the respective melting peaks were integrated to obtain the sum of the heat capacities.

F. Melt viscosity η
Using a Capillograph 1B manufactured by Toyo Seiki Co., Ltd., in a nitrogen atmosphere, a resin having a melting point of 240 ° C. or lower is 240 ° C., and in the case of a resin having a melting point of 240 ° C. or higher, a melting point + 20 ° C. and a shear rate of 1216 sec. The melt viscosity of the aliphatic polyester resin (component A) and the thermoplastic polyamide resin (component B, component C) in ^-1 was measured. The measurement was performed 3 times and the average value was taken as the melt viscosity.

G. Identification of polymer alloy structure An ultra-thin section is cut in a direction perpendicular to the fiber axis of the core-sheath composite fiber, the polyamide component of the section is metal-stained with phosphotungstic acid, and a 40,000 times transmission electron microscope (TEM) The polymer alloy structure was observed and photographed. At this time, the case where the island component is not dyed is determined as the polymer alloy structure (a), and the case where the island component is dyed is determined as the polymer alloy structure (b), and the island component and the sea component cannot be distinguished. The case where each component does not exhibit a substantially circular shape and cannot distinguish between an island and the sea was identified as a polymer alloy structure (c).

TEM device: Hitachi H-7100FA type Conditions: Acceleration voltage 100 kV.

H. Measurement of island component diameter In G, if the polymer alloy structure is determined to be (a) or (b), use the image analysis software “WinROOF” of Mitani Shoji Co., Ltd. Assuming that the island component is a circle, the diameter converted from the area of the island component was measured as the diameter of the island component. The number of islands to be measured was 100 per sample, and the distribution was the diameter distribution of island components.

I. Blend ratio of component A / component B (weight ratio)
The weights of component A and component B when subjected to melt spinning were weighed and calculated from the blend ratio of component A and component B.

  In the production process, when it was difficult to measure each of component A and component B, the blend ratio (weight ratio) of component A / component B was calculated from the core-sheath composite fiber. The core component of the core-sheath type composite fiber of the present invention may contain component A, component B, and other minor components. In such a case, the core component consists essentially of only two components, component A and component B. As a result, the blend ratio (weight ratio) of component A / component B can be calculated.

  Using the image taken in section G, the total area (Aa) of component A and the total area (Ab) of component B are determined using the image analysis software “WinROOF” of Mitani Corporation. The specific gravity of component A was 1.26 and the specific gravity of component B was 1.14, and calculation was performed using the following formula.

  Component A / Component B = (Aa × 1.26) / (Ab × 1.14).

  In this case, when it is difficult to distinguish the boundary line between the sheath component and the core component in the cross section, the cross section is circumscribed with the component A existing in the outermost layer and is similar to the fiber cross section including only the component A inside. Using the figure as the boundary line, the sheath component and the core component were distinguished.

J. et al. Sheath Component Thickness In G, using the photographed image, the sheath component and the core component were discriminated, and the thickness of the sheath component was measured at 10 random locations to determine the average value. Moreover, it measured about the thickness of the thinnest part of a sheath component, and set it as the minimum value of the thickness of a sheath component. When it was difficult to discriminate the boundary line between the sheath component and the core component in the cross section, it was discriminated by the same method as in the item I.

K. Content of Component A 10 g of the core-sheath type composite fiber was taken out, and its weight (W1) was weighed to prepare a sample. The sample was immersed in 500 ml of chloroform at 25 ° C. for 24 hours to completely leach component A. The core-sheath composite fiber after the leaching treatment was washed with water and dried at 25 ° C. for 24 hours, and then the weight (W2) of the fiber was weighed. Using W1 and W2, the content of component A was calculated by the following formula.

  Content of component A (% by weight) = (W1-W2) × 100 / W1.

L. Strength and elongation A sample (core-sheath type composite fiber) was measured with a Tensilon UCT-100 manufactured by Orientec Co., Ltd. under the constant speed elongation conditions shown in JIS L1013 (chemical fiber filament yarn test method, 1998). did. In addition, elongation was calculated | required from elongation of the point which showed the maximum strength in a SS curve.

M.M. Boiling water shrinkage (boiling yield)
The core-sheath type composite fiber was immersed in boiling water for 15 minutes, and obtained from the following formula from the dimensional change before and after the immersion.

Boiling water shrinkage rate (%) = [(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: The skein length measured under an initial load of 0.088 cN / dtex after treating the skein whose L0 was measured with boiling water in a load-free state and drying it at 25 ° C. and a dry humidity of 65% for 24 hours.

N. Yarn spots U%
The core-sheath type composite fiber was used as a sample, and UT4-CX / M manufactured by Zellwegen Uster was used to measure U% (Normal) at a yarn speed of 200 m / min and a measurement time of 1 minute.

O. Using the image taken in the section of the degree of irregularity F, the diameter was determined from the circumscribed circle diameter D1 of the single fiber cross section and the inscribed circle diameter D2 of the single yarn cross section by the following equation.

  Deformity = D1 / D2.

P. Crimp elongation after boiling water treatment A crimped yarn unwound from a package that had been allowed to stand for 24 hours in an atmosphere at room temperature of 25 ° C. and a relative humidity of 65% was immersed in boiling water for 30 minutes in an unloaded state. Thereafter, the sample was dried at room temperature of 25 ° C. and relative humidity of 65% for 24 hours, and this was used as a sample for measuring the crimp elongation after the boiling water treatment. An initial load of 2 mg / dtex was applied to this sample in an atmosphere at room temperature of 25 ° C. and relative humidity of 65%, and after 30 seconds, the sample length was marked to 50 cm (L1). Next, after removing the initial load, a constant load of 100 mg / dtex was applied to the sample, and the sample length (L2) that was extended after 30 seconds was measured. And the elongation rate (%) after a boiling water process was calculated | required by the following formula.

  Elongation rate (%) after boiling water treatment = [(L2-L1) / L2] × 100.

Q. Elongation rate after boiling water treatment under 2 mg / dtex load (Elongation rate under restraint load)
In the term of P, when dipping with boiling water, in the state where the load of 2 mg / dtex was suspended on the crimped yarn, except that the crimped yarn was treated with boiling water, the same as in the term of P, The elongation rate under restraining load was measured.

R. Wear resistance evaluation of drawn yarn Wrap sandpaper (P600) around a roller that rotates at a constant rotation speed, fix one end of the drawn yarn to the wall as shown in Fig. 3, apply a load to the other end, While traversing the drawn yarn at a constant speed, the roller was rotated to scrape the drawn yarn with sandpaper, and the number of roller rotations until the drawn yarn was cut was measured. The measurement conditions are shown below.

Rotating body diameter: 80mm
Yarn contact length: 62.8 mm
Yarn contact angle: 90 °
Roller rotation speed: 160rpm
Traverse width: 10mm
Traverse speed: 3 times Measurement load: 0.06 cN / dtex.

S. Abrasion resistance evaluation of crimped yarn After twisting the two twisted yarns by applying S twist and Z twist to the crimped yarn, and tufting the PP spunbond nonwoven fabric as the front yarn, the back of the base fabric A backing material was applied to the film and dried to obtain a tufting carpet (weight per unit area: 1200 g / m ² ).

  The tufting carpet was cut into a circular shape having a diameter of 120 mm, and a 6 mm hole was formed in the center to obtain a test piece. The test piece is attached to a Taber abrasion tester (Rotary Abaster) specified in ASTM D 1175 (1994) with the surface facing upward, an H # 18 abrasion rod, a compression load of 1 kgf, a sample holder rotational speed of 70 rpm, and a wear frequency of 5500. The sample weight before and after the wear test was measured. The wear weight loss rate was calculated using these measured values and the following equation.

Wear loss rate (%) = (W0−W1) × 100 / (W2 × A1 / A0)
W0: Weight of circular carpet before measurement (g)
W1: Weight of the circular carpet after measurement (g)
W2: Carpet weight (g / m ² )
A0: Total area of circular carpet (m ² )
A1: Total area (m ² ) of the portion where the wear ring contacts.

S. Evaluation of spinning property When a 100 kg cheese package was obtained, the spinning property was evaluated based on the number of times yarn breakage occurred. Evaluation was made in four stages: excellent (double circle), good (◯), acceptable (Δ), and impossible (×).

Double circle: No thread break ○: 1 to 5 thread breaks Δ: 6 to 10 thread breaks ×: 11 or more thread breaks

T.A. Iron heat resistance A circular knitting made of a core-sheath type composite fiber is produced, and when the iron surface temperature of the steam iron (Steam Iron A-1F manufactured by Sanyo Electric Co., Ltd.) reaches 170 ° C., the iron weight ( Pressing was performed at a surface pressure of about 8 g / cm ² ) for 10 seconds, and the appearance change after pressing was evaluated according to the following criteria.

Double circle: No change in appearance ○: Slight attrition △: Clear attrition ×: Partial fusion between fibers XX: Perforation due to melting

[Production Example 1] (Production of polylactic acid, PLA-1)
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. And polylactic acid (PLA-1) was obtained. The weight average molecular weight of the obtained polylactic acid was 210,000. The amount of lactide remaining was 0.13% by weight. The polymer had a melting point of 170 ° C. and a melt viscosity of 200 Pa · sec ⁻¹ .

[Production Example 2] (Production of polylactic acid, PLA-2)
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. And polylactic acid (PLA-2) was obtained. The weight average molecular weight of the obtained polylactic acid was 150,000. The amount of residual lactide was 0.10% by weight. The polymer had a melting point of 170 ° C. and a melt viscosity of 120 Pa · sec ⁻¹ .

[Production Example 3] (Production of polylactic acid, PLA-3)
Lactide produced from L-lactic acid having an optical purity of 99.5%, lactide produced from D-lactic acid having an optical purity of 99.5%, and bis (2-ethylhexanoate) tin catalyst (L-lactic acid lactide: D-lactic acid lactide: Polymerization was carried out at 180 ° C. for 220 minutes in the presence of a catalyst molar ratio = 8900: 1100: 1) to obtain polylactic acid (PLA-3). The obtained polylactic acid had a weight average molecular weight of 212,000. The amount of lactide remaining was 0.12% by weight. The polymer had a melting point of 130 ° C. and a melt viscosity of 200 Pa · sec ⁻¹ .

Example 1
Polylactic acid (PLA-1, melting point 170 ° C., melt viscosity 200 Pa · sec ⁻¹ ) as component A, Nylon 6 (N6-1, melting point 225 ° C., melt viscosity 60 Pa · sec ⁻ ) as component B sulfuric acid relative viscosity 2.15 ¹ ) Nylon 6 (N6-2, melting point 225 ° C., melt viscosity 150 Pa · sec ⁻¹ ) having a relative viscosity of sulfuric acid of 2.60 as component C was dried to adjust the moisture content to 50 to 100 ppm.

  When melt spinning is performed using a spinning device equipped with the twin-screw kneader shown in FIG. 1, the blend ratio of component A (PLA-1) / component B (N6-1) is added to the core component hopper of the spinning hopper 1. = 40/60 (weight ratio) are separately weighed and chip-blended and charged, and component C (N6-2) is charged into the sheath component hopper of the spinning hopper 2, and component A and component B are mixed. The blend polymer and component C are separately melted and kneaded by the twin-screw extrusion kneaders 3 and 4 respectively, and guided to the spinning block 5, and the respective polymers are measured and discharged by the gear pumps 6 and 7, and the built-in spinning Guided to pack 8 and spun from spinneret 9. At this time, the rotation speed of the gear pump of the core component and the sheath component was selected so that the composite ratio of the core component / sheath component = 80/20 (weight ratio). 32% by weight of A). Then, the yarn 11 was cooled and solidified by the uniflow cooling device 10 and supplied by the oil supply device 12. Furthermore, after taking up with the 1st roll 13, it extends | stretches with the speed ratio of the 2nd roll 14 and the 3rd roll 15, heat-processes with the 3rd roll 15, cools a thread | yarn to room temperature with the 4th roll 16, and winds up By winding with a machine 17, a drawn yarn (cheese package 17) of 900 dtex 60 filaments subjected to spinning, drawing and heat treatment in one stage was obtained. About 100 kg of spinning was sampled, but no yarn breakage or single yarn flow occurred, and the spinning was extremely stable.

  Since the melt viscosity of component A was 200 Pa · s and the melt viscosity of component B was 60 Pa · s, the melt viscosity ratio ηb / ηa was 0.30.

  The melt spinning conditions are as follows.

-Kneader temperature: 230 ° C
・ Spinning temperature: 240 ℃
Filter layer: 30 # Morundum sand filling Filter: 20 μm nonwoven filter Filter base 1 (base just before polymer discharge): hole diameter 0.6 mm, discharge hole length 1.2 mm, number of holes 60
・ Base 2 (in front of the base 1 and having separate flow paths for the core component and the sheath component):
Sheath component: 0.4 mm hole diameter, 0.5 mm discharge hole length, 4 holes per filament
Core component: hole diameter 0.6mm, discharge hole length 0.9mm, 1 hole per filament
・ Discharge rate: 270 g / min (1 pack 1 yarn, 60 filaments)
・ Cooling: Uniflow with a cooling length of 1 m is used. The cooling air temperature is 20 ° C., the wind speed is 0.5 m / second, and the cooling start position is 0.1 m below the base surface.

・ Oil agent: Fatty acid ester 10% concentration emulsion oil agent 10% adhered to the yarn ・ First roll speed: 750 m / min ・ Second roll speed: 775 m / min ・ Third roll speed: 3100 m / min ・ Fourth roll speed : 3050 m / min Winding speed: 3000 m / min First roll temperature: 25 ° C
-Second roll temperature: 80 ° C
-Third roll temperature: 140 ° C
-4th roll temperature: 25 degreeC.

  When the TEM observation of the cross section of the obtained fiber was performed, it had a uniformly dispersed sea-island structure, and the diameter of the island component was 0.05-0.20 μm. Moreover, since the non-dyeing component forms an island component, the component A has an island and the component B has a sea-island structure (polymer alloy structure (a)).

  Further, the obtained fiber showed good fiber properties such as strength 4.5 cN / dtex, elongation 45%, boiling water shrinkage 10%, and yarn unevenness U% 0.8%. Furthermore, the yarn cutting rotation speed by the abrasion test was 1142, and there was no fibrillation during the test, and the abrasion resistance was excellent.

  When a circular knitting of the core-sheath type composite fiber was prepared and an iron heat resistance test was performed, the appearance was not changed at all and the fiber was excellent in heat resistance. And when DSC of this fiber was measured, the melting peak derived from each component was observed in the vicinity of 170 ° C. (peak derived from component A) and in the vicinity of 225 ° C. (peak derived from component B and component C). The sum total of the heat capacities of the respective melting peaks was 72 J / g and had sufficient crystallinity.

(Example 2 , Reference Examples 3 to 5, Comparative Example 1)
In Example 1, the stretched yarns of Example 2 , Reference Examples 3 to 5, and Comparative Example 1 were used in the same manner as in Example 1 except that the blend ratio of component A and component B filled in the core component hopper was changed. Obtained. The results of Example 2 , Reference Examples 3 to 5, and Comparative Example 1 are shown in Table 1, and the blend ratio (weight ratio) of Component A and Component B in each is shown below.

Example 2: Component A / Component B = 20/80
Reference Example 3: Component A / Component B = 55/45
Reference Example 4: Component A / Component B = 70/30
Reference Example 5: Component A / Component B = 90/10
Comparative Example 1: Component A / Component B = 100/0
As can be seen from Examples 1-2, Reference Examples 3-5, and Comparative Example 1, by setting the blend ratio of the component A and the component B of the core component to the preferred range in the present invention, the polymer of the core component A core-sheath type composite fiber having an alloy structure and a diameter of an island component in a preferable range can be obtained. For this reason, even if the content of component A is high, a drawn yarn excellent in wear resistance and heat resistance can be obtained. Table 1 shows the results of Examples 1-2, Reference Examples 3-5, and Comparative Example 1.

(Examples 6 to 8, Comparative Example 2)
In Example 1, the composite ratios of the core component and the sheath component were changed, and the thicknesses of the sheath component of the obtained drawn yarn were changed, and the stretches of Examples 6 to 8 and Comparative Example 2 were performed in the same manner as in Example 1. I got a thread. In Examples 6-7, the yarn production was excellent without yarn breakage, whereas in Example 8, yarn breakage occurred once in 100 kg spinning, and in Comparative Example 2, the spun yarn had a large ballast and fineness. The turning point was likely to fluctuate, and yarn breakage occurred six times in 100 kg spinning. The results of Examples 6 to 8 and Comparative Example 2 are shown in Table 2. The composite ratio (weight ratio) of the core component and the sheath component in each is shown below. In Comparative Example 2, the following specifications having no sheath component flow path were used as the cap 2.

Example 6: Core component / sheath component = 85/15
Example 7: Core component / sheath component = 90/10
Example 8: Core component / sheath component = 95/5
Comparative Example 2: Core component / sheath component = 100/0
Base 2 of Comparative Example 2: sheath component no hole, core component hole diameter 0.6 mm, discharge hole length 0.9 mm, 1 hole per filament
As can be seen by comparing Example 1 (Table 1), Examples 6 to 8, and Comparative Example 2 (Table 2), the core-sheath type composite fiber of the present invention has good abrasion resistance by having a sheath component. It can be seen that It can also be seen that the thicker the sheath component, the more excellent the abrasion resistance and the suppression of the occurrence of ballast in the spun yarn, so that it is possible to obtain a drawn yarn having excellent yarn-making properties and excellent uniformity.

( Reference Example 9)
In Example 1, except that polylactic acid (PLA-3, melting point 130 ° C., melt viscosity 200 Pa · sec ⁻¹ ) was used as component A, spinning, stretching, and heat treatment were performed in the same manner as in Example 1 for reference example. Nine drawn yarns were obtained. Smoke was confirmed from the spun yarn, and yarn breakage occurred three times in the production of a 100 kg drawn yarn. The obtained drawn yarn had a wear resistance of 511 times, a strength of 2.5 cN / dtex, and U% 1.8, and Example 1 was more excellent in wear resistance, strength, and uniformity than Reference Example 9. . The results of Reference Example 9 are shown in Table 3.

As can be seen by comparing Example 1 (Table 1) and Reference Example 9 (Table 3), by using an aliphatic polyester resin having a melting point range that is preferable in the present invention as Component A, the components in the spinning process It can be seen that the thermal deterioration of A can be suppressed, and in the core component of the obtained core-sheath composite fiber, the polymer alloy structure and the diameter of the island component that are preferable in the present invention can be easily formed.

(Examples 10 to 12, Reference Examples 13 to 14 )
In Example 1, except that the polyamide resins used as Component B and Component C were changed, spinning, stretching, and heat treatment were performed in the same manner as in Example 1, and the stretched yarns of Examples 10 to 12 and Reference Examples 13 to 14 were used. Got. Since Reference Examples 13 and 14 were polyamide resins having a melting point of 260 ° C., spinning was carried out at a kneader temperature of 270 ° C. and a spinning temperature of 280 ° C. in order to melt the polyamide resin. About Examples 10-12, generation | occurrence | production of the ballast was small like Example 1, and the yarn production was extremely stable, but the spun yarns of Reference Examples 13-14 produced fuming that was considered to be caused by thermal decomposition of Component A. Observed ballast was large. In Reference Example 13, yarn breakage was observed 9 times, and in Reference Example 14, yarn breakage was observed 8 times, and Example 1 was superior in yarn production. The results of Examples 10 to 12 and Reference Examples 13 to 14 are shown in Table 3. In addition, the polyamide resin used for the component B and the component C in Examples 10-12 and Reference Examples 13-14 is shown below.

Example 10: Component B = N610-1, Component C = N610-2
Example 11: Component B = N6 / N66, Component C = N6-2
Example 12: Component B = N6-1, Component C = N11
Reference Example 13: Component B = N66-1, Component C = N6-2
Reference Example 14: Component B = N6-1, Component C = N66-2
N6 / N66: nylon in which N6 and N66 are copolymerized at a molar ratio of 80/20, sulfuric acid relative viscosity 2.20, melting point 200 ° C., melt viscosity 60 Pa · sec ⁻¹ )
N610-1: Nylon 610, sulfuric acid relative viscosity 2.15, melting point 225 ° C., melt viscosity 60 Pa · sec ⁻¹
N610-2: nylon 610, sulfuric acid relative viscosity 2.60, melting point 225 ° C., melt viscosity 150 Pa · sec ⁻¹
N66-1: Nylon 66, sulfuric acid relative viscosity 2.15, melting point 260 ° C., melt viscosity 60 Pa · sec ⁻¹
N66-1: Nylon 66, sulfuric acid relative viscosity 2.60, melting point 260 ° C., melt viscosity 150 Pa · sec ⁻¹
N11: nylon 11, melting point 185 ° C., melt viscosity 150 Pa · sec ⁻¹
As can be seen from Tables 1 and 3, the drawn yarns of Example 1 (Table 1) and Examples 10 to 11 (Table 3) are drawn yarns having better abrasion resistance than Example 12 (Table 3). . That is, in the present invention, the component B and the component C are composed of a polyamide resin whose main component is the same type of monomer, so that the adhesiveness at the interface between the core component and the sheath component is improved, and the drawn yarn excellent in wear resistance. It turns out that it becomes.

Further, as can be seen from Example 1 (Table 1), Examples 10 to 12, and Reference Examples 13 to 14 (Table 3), polyamides having a melting point range which is preferably used in the present invention as Component B and Component C. By adopting, it becomes possible to perform melt spinning at a temperature at which the thermal decomposition of component A does not occur easily. Thereby, the melt viscosity of the component A can be kept high during the period from melting the polymer to spinning. For this reason, since it becomes easy to form the polymer alloy structure a considered preferable in this invention, and it becomes a drawn yarn which does not contain a coarse island component, it turns out that it becomes a drawn yarn excellent in abrasion resistance.

( Reference Examples 15 to 17)
In Example 1, except that the thermoplastic resins used as Component A and Component B were changed, spinning, stretching and heat treatment were performed in the same manner as in Example 1 to obtain stretched yarns of Reference Examples 15 to 17. In Reference Example 15, the yarn was broken twice and good yarn forming property was exhibited. In Reference Examples 16 and 17, since the ball in the spun yarn was large and the yarn was slightly swayed, and the yarn breakage was 7 times and 8 times, the reference example 15 was better in yarn production. The results of Reference Examples 15 to 17 are shown in Table 4. It shows below about the component A and the component B which were used in Reference Examples 15-17.

Reference Example 15: Component A = PLA-1, Component B = N6-2
Reference Example 16: Component A = PLA-2, Component B = N6-2
Reference Example 17: Component A = PLA-2, Component B = N6-3
N6-3: Nylon 6, sulfuric acid relative viscosity 3.15, melting point 225 ° C., melt viscosity 300 Pa · sec ⁻¹

Comparing Example 1 (Table 1) and Reference Examples 15 to 17 (Table 4), in the present invention, by selecting the viscosity ratio of Component A and Component B within a preferred range, the polymer alloy structure of the core component, the island It turns out that the diameter of a component can be made into the preferable range of this invention, and becomes a core-sheath-type composite fiber which is more excellent in abrasion resistance.

(Examples 18 to 19)
In Example 1, except that the polyamide resin used as Component C was changed, spinning, stretching, and heat treatment were performed in the same manner as in Example 1 to obtain stretched yarns of Examples 18 to 19. The component C used in Examples 18 to 19 is shown below, and the results of Examples 18 to 19 are shown in Table 4.

Example 18: Component C = N6-1
Example 19: Component C = N6-3
When Example 1 (Table 1) and Examples 18 to 19 (Table 4) are compared, by adopting a polyamide having a melt viscosity in a preferred range as Component C in the present invention, a drawn yarn having excellent wear resistance is obtained. I understand that. In Example 19, the eccentricity of the core component (differing in the center of gravity of the core component and the sheath component) was confirmed in the fiber cross-sectional observation, and the thickness of the sheath component varied depending on the location.

(Example 20)
In Example 1, as a spinning machine, a spinning continuous crimping apparatus provided with the twin-screw kneader shown in FIG. 2 was used, and melt spinning, stretching, heat treatment, and crimping were continuously performed, and air stuffer crimping was performed. I got a thread.

  In the core component hopper 18 shown in FIG. 2, component A (PLA-1) / component B (N6-1) are separately weighed so that the blend ratio = 40/60 (weight ratio) and chip blended. The component C (N6-2) is charged into the sheath component hopper 19, and the blend polymer of component A and component B and component C are separately melted and kneaded in the twin-screw extrusion kneaders 20 and 21, respectively. Then, each polymer is measured and discharged by the gear pumps 23 and 24, led to the built-in spin pack 25, and spun from the spinneret 26 having 120 holes for the three-leaf cross-section die. did. At this time, the rotation speed of the gear pump of the core component and the sheath component was selected so that the composite ratio of the core component / sheath component = 80/20 (weight ratio). 32% by weight of A). Then, the yarn 28 was cooled and solidified by the uniflow cooling device 27 and supplied by the oil supply device 29. Furthermore, after taking up with the 1st roll 30, it extends | stretches with the speed ratio of the 2nd roll 31 and the 3rd roll 32, heat-processes with the 3rd roll 32, and further according to the speed ratio of the 3rd roll 32 and the 4th roll 33 Stretching is performed, heat treatment is performed again with the fourth roll 33, and air stuffer crimping is imparted by the crimping treatment nozzle 34 using a heating fluid while relaxing the yarn between the fourth roll and the fifth roll. Then, the crimped yarn is cooled to room temperature on the surface of the fifth roll 35 to fix the structure, and tension (0.05 to 0.10 cN / s) that does not stretch the crimp between the sixth roll 36 and the seventh roll 37. 1800 dtex 120 in which spinning, drawing, heat treatment, and crimping treatment are performed in one stage by stretching while applying the dtex (fineness is the fineness of the crimped yarn that has been wound) and winding with a winder 38. It was obtained to obtain an air stuffer crimped yarn of Iramento the (cheese package 39). Although about 100 kg was sampled, yarn breakage, single yarn flow, etc. did not occur, and the yarn production was extremely stable. The results of Example 20 are shown in Table 5.

  The melt spinning, drawing, heat treatment, and crimping treatment conditions are as follows.

-Kneader temperature: 230 ° C
・ Spinning temperature: 240 ℃
-Filter layer: 30 # Morundum sand filling-Filter: 20 μm non-woven filter-Base: Slit width 0.15 mm, Slit length 1.5 mm, Number of holes 120
・ Base 1 (Base just before polymer discharge): slit width 0.15 mm, slit length 1.5 mm, number of holes 120
Base 2 (base of schematic diagram 47 in FIG. 9 and immediately before base 1 and having separate flow paths for the core component and the sheath component):
Sheath component: 0.4 mm hole diameter, 0.5 mm discharge hole length, 4 holes per filament
Core component Slit width 0.08mm, slit length 1.2mm, 1 hole per filament
・ Discharge rate: 360 g / min (1 pack, 1 thread, 120 filaments)
・ Cooling: Uniflow with a cooling length of 1 m is used. Cooling air temperature 20 ° C, wind speed 0.5m / sec, cooling start position 0.1m below the base
・ Oil agent: Fatty acid ester 10% concentration emulsion oil agent adheres to yarn 10% ・ First roll temperature: 25 ° C.
-Second roll temperature: 75 ° C
-Third roll temperature: 140 ° C
-Fourth roll temperature: 190 ° C
-5th roll temperature: 25 degreeC
-Sixth roll temperature: 25 ° C
-Seventh roll temperature: 25 ° C
・ Heating steam treatment temperature: 225 ℃
First roll speed: 690 m / min Second roll speed: 700 m / min Third roll speed: 1750 m / min Fourth roll speed: 2800 m / min Fifth roll speed: 80 m / min Sixth roll speed : 2000 m / min. Seventh roll speed: 2040 m / min. Winding speed: 2000 m / min.

  When the TEM observation of the cross section of the obtained air stuffer crimped yarn was performed, it had a uniformly dispersed sea-island structure, and the diameter of the island component was 0.05-0.30 μm. Further, since the non-dyed component forms an island component, the component A has an island and the component B has a sea-island structure (polymer alloy structure a). Moreover, it was a crimped yarn having a crimped elongation rate of 25% and an elongation rate of 19% under a restrained load, excellent crimp characteristics, and having a crimp that is difficult to set. As a result of producing a carpet using the crimped yarn and carrying out an abrasion resistance test, it showed an excellent abrasion resistance with an abrasion loss rate of 10%. In addition, as a result of producing a round knitted crimped yarn and evaluating the iron heat resistance, the outer appearance did not change at all and showed excellent heat resistance. The melting point of DSC of the crimped yarn was observed at around 170 ° C. (peaks derived from component A) and around 225 ° C. (peaks derived from component B and component C), and melting peaks attributable to the respective components were observed. The sum of the heat capacities of the melting peaks was 74 J / g, indicating sufficient crystallinity.

(Examples 21 to 24, Comparative Example 3)
In Example 20, the air stuffer crimped yarns of Examples 21 to 24 and Comparative Example 3 were made in the same manner as in Example 20 except that the blend ratio of Component A and Component B filled in the core component hopper was changed. Obtained. The results of Examples 21 to 24 and Comparative Example 3 are shown in Table 5, and the blend ratio (weight ratio) of Component A and Component B in each is shown below.

Example 21: Component A / Component B = 20/80
Example 22: Component A / Component B = 55/45
Reference Example 23: Component A / Component B = 70/30
Reference Example 24: Component A / Component B = 90/10
Comparative Example 3: Component A / Component B = 100/0
From Examples 20 to 22 , Reference Examples 23 to 24 , and Comparative Example 3, the crimped yarn of the core-sheath composite fiber of the present invention has component B as the core component, so that component B of the core component, sheath component Due to the interaction of component C, the adhesion at the core-sheath interface is enhanced, and excellent wear resistance is exhibited. In addition, by setting the blend ratio of the component A and the component B of the core component to be within a preferable range in the present invention, the polymer alloy structure of the core component and the diameter of the island component can be set within a preferable range, and wear resistance Air stuffer crimped yarn excellent in the above can be obtained. And since it has a crimp that is difficult to loosen, it is possible to maintain the quality typified by the bulkiness when used as a carpet even during long-term use, and to obtain a carpet without wear-resistant aging.

(Examples 25-27, Comparative Example 4)
In Example 20, the air stuffer crimping of Examples 25 to 27 was performed in the same manner as in Example 20 except that the composite ratio of the core component and the sheath component was changed and the thickness of the sheath component of the obtained drawn yarn was changed. I got a thread. For Comparative Example 4, an attempt was made to obtain a crimped yarn under the same conditions as in Example 20, but component A exposed on the fiber surface was heat-sealed to the surface of the fourth roll, making yarn production impossible. Met. Then, the temperature of the 4th roll was 140 degreeC, the temperature of the 3rd roller was 100 degreeC, and the air stuffer crimped yarn of the comparative example 4 was obtained.

  In Examples 25 to 26, yarn breakage was excellent with no yarn breakage, whereas in Example 27, yarn breakage occurred twice in 100 kg spinning, and in Comparative Example 4, the spun yarn had a large ballast and thinness. The turning point was likely to fluctuate, and yarn breakage occurred three times in 100 kg spinning. The results of Examples 25 to 27 and Comparative Example 4 are shown in Table 6, and the composite ratio (weight ratio) of the core component and the sheath component in each is shown below.

Example 25: core component / sheath component = 85/15
Example 26: core component / sheath component = 90/10
Example 27: Core component / sheath component = 95/5
Comparative Example 4: Core component / sheath component = 100/0

  When Example 20 (Table 5), Examples 25 to 27 (Table 6), and Comparative Example 4 (Table 6) are compared, the core-sheath composite fiber of the present invention has a sheath component, so that the crimp elongation rate A crimped yarn having a high elongation rate, a high elongation rate under a restraining load and excellent wear resistance can be obtained. In addition, the thicker the sheath component, not only is excellent in abrasion resistance, but also has a high elongation rate under restraining load, that is, a high-quality crimped yarn that is difficult to crimp. Furthermore, the thicker the sheath component, the more the generation of the ball in the spun yarn can be suppressed, and the crimped yarn having good yarn-making property and high uniformity can be obtained.

(Examples 28 to 32)
In Example 20, except that the temperature of the fourth roll was changed, spinning, drawing, heat treatment, and crimping treatment were performed in the same manner as in Example 20 to obtain an air stuffer crimped yarn. In Examples 28 to 31, the spun yarn had little occurrence of ballast, there was no yarn breakage, and the spinning was extremely stable. However, in Example 31, some yarn swaying occurred on the fourth roll, resulting in yarn breakage. Happened once. The results of Examples 28 to 32 are shown in Table 7. Moreover, it shows below about the temperature of the 4th roll in Examples 28-32.

Example 28: Temperature of the fourth roll = 140 ° C.
Example 29: Temperature of the fourth roll = 150 ° C.
Example 30: Fourth roll temperature = 175 ° C
Example 31: Temperature of the fourth roll = 200 ° C.
Example 32: Fourth roll temperature = 210 ° C

  As can be seen from a comparison between Example 20 (Table 5) and Examples 29 to 30 (Table 7) and Examples 28 and 32 (Table 7), the cocoon having a crimp elongation rate preferred in the present invention. It can be seen that the wear resistance is drastically improved by using the reduced yarn. Since the crimped yarns of Examples 20 and 29 to 30 are crimped yarns having an appropriate crimp elongation rate, the crimped yarns are not easily collapsed when worn by an external force, and moderate bending or Due to the entanglement, the external force was dispersed in each single yarn and exhibited excellent wear resistance.

(Examples 33 to 35)
In Example 20, the spinning, drawing, heat treatment, and crimping treatments were performed in the same manner as in Example 20 except that the specifications of the base hole used were changed and the deformed degree of the resulting air stuffer crimped yarn was changed. And air stuffer crimped yarns of Examples 33 to 35 were obtained. The results of Examples 33 to 35 are shown in Table 8. Moreover, the nozzle | cap | die hole specification used in Examples 33-35 is shown below.

Example 33
Base 1 (Base just before polymer discharge): slit width 0.20 mm, slit width 0.8 mm, number of holes 120
Example 34
Base 1 (Base just before polymer discharge): slit length 0.18 mm, slit width 1.0 mm, number of holes 120
Example 35
Base 1 (Base just before polymer discharge): slit length 0.12 mm, slit width 1.8 mm, number of holes 120

  As can be seen by comparing Example 20 (Table 5) and Examples 33 to 35 (Table 8), by using an air stuffer crimped yarn having a high degree of deformation in the present invention, it is excellent in abrasion resistance. Become. That is, in the present invention, the higher the degree of deformation of the crimped yarn, the more easily the diameter of the island component is made finer in the spinning process, and since the island has a polymer alloy structure in which the islands are uniformly dispersed, component A and component B and / or component C Adhesiveness at the interface was increased, and a crimped yarn excellent in abrasion resistance without fibrillation was obtained. Furthermore, by using a crimped yarn having a high degree of irregularity, it became a crimped yarn that was difficult to set, and a crimped yarn that did not deteriorate in wear resistance even after long-term use.

It is the schematic of the apparatus which performs spinning, extending | stretching, and heat processing preferable for manufacturing the core-sheath-type composite fiber of this invention in one step. It is the schematic which shows the apparatus which performs a spinning, extending | stretching, heat processing, and a crimping process in one step preferable for manufacturing the crimped yarn of the core-sheath-type composite fiber of this invention. It is the schematic of the measuring apparatus which performs the abrasion resistance test of the drawn yarn of the core-sheath-type composite fiber of this invention. It is an explanatory photograph of air stuffer crimped yarn (multifilament). It is an explanatory photograph of air stuffer crimped yarn (single yarn). It is an explanatory photograph of the sea island structure. It is a schematic diagram which shows the cross-sectional shape of a core-sheath-type composite fiber. It is a schematic diagram explaining a discharge hole length, a hole diameter, a slit length, and a slit width. It is a cross-sectional schematic diagram of the nozzle | cap | die of a core sheath type composite fiber.

Explanation of symbols

1: core component hopper 2: sheath component hopper 3: core component biaxial extrusion kneader 4: sheath component biaxial extrusion kneader 5: spinning block 6: core component gear pump 7: sheath component gear pump 8: spinning pack 9: Spinneret 10: Uniflow cooling device 11: Thread 12: Oil supply device 13: First roll 14: Second roll 15: Third roll 16: Fourth roll 17: Winder 18: Cheese package 19: Core component Hopper 20: sheath component hopper 21: twin screw extrusion kneader for core component 22: twin screw extrusion kneader for sheath component 23: spinning block 24: gear pump for core component 25: gear pump for sheath component 26: spinning pack 27: spinneret 28: Uniflow cooling device 29: Yarn 30: Oil supply device 31: First roll 32: Second roll 33: Third roll 34: Fourth roll 35: Crimp nozzle
36: 5th roll 37: 6th roll 38: 7th roll 39: Winder 40: Cheese package 41: Core component (polymer alloy)
42: sheath component 43: discharge hole length 44: hole diameter 45: slit length 46: slit width 47: base 1 (base immediately before discharge)
48: Base 2 (in front of base 1 and having separate flow paths for the core component and the sheath component)
49: drawn yarn 50: wear roller 51: load

Claims (11)

The core component is an aliphatic polyester resin (A), the comprises a polymer alloy of a thermoplastic polyamide resin (B), the sheath component Ri name contains a thermoplastic polyamide resin (C), the core component of the polymer alloy core-sheath composite yarn alloy structure you and satisfies the (1) to (3) below.
(1) The aliphatic polyester resin (A) forms an island component
(2) The thermoplastic polyamide resin (B) forms a sea component
(3) The diameter of the island component is 0.001 to 2 μm. The core-sheath type composite fiber according to claim 1, wherein the blend ratio (weight ratio) of the aliphatic polyester resin (A) and the thermoplastic polyamide resin (B) is 95/5 to 20/80. The core-sheath type composite fiber according to claim 1 or 2, wherein the sheath component has a thickness of 0.4 to 10 µm. The core-sheath-type conjugate fiber according to any one of claims 1 to 3 , wherein a sum of heat capacities of melting peaks of a differential calorific value curve measured at a heating rate of 16 ° C / min is 50 J / g or more. A crimped yarn comprising the core-sheath composite fiber according to any one of claims 1 to 4 . The crimped yarn according to claim 5 , wherein the crimped form is an air stuffer crimp. The crimped yarn according to claim 5 or 6 , wherein the crimped yarn satisfies the following physical properties (4) to (6).
(4) Strength: 1.5-4 cN / dtex
(5) Crimp elongation after boiling water treatment: 5-35%
(6) Deformity (D1 / D2): 1.3-8 The crimped yarn according to any one of claims 5 to 7 , which has a crimp elongation (elongation rate under constraint load) of 3% or more and 30% or less measured after boiling water treatment under a load of 2 mg / dtex. A fiber structure comprising at least a part of the core-sheath type composite fiber according to any one of claims 1 to 4 or the crimped yarn according to any one of claims 5 to 8 . The fiber structure according to claim 9 , wherein the fiber structure is a carpet for automobile interior. The aliphatic polyester resin (A) and the thermoplastic polyamide resin (B) are mixed in a biaxial extrusion kneader and / or a single screw extrusion kneader, and the kneading temperature is set to the melting point (Tmb) of the thermoplastic polyamide resin (B). Tmb + 40 ° C., shear rate 200-20,000 sec ⁻¹ , core component comprising polymer alloy melt-kneaded in the range of residence time 0.5-30 minutes, and sheath component comprising thermoplastic polyamide resin (C) Are spun together and spun by a spinneret, and the spun, unstretched core-sheath type composite fiber is taken up by a roll, and then drawn, stretched, and heat-treated by a direct spinning-stretching method that continuously stretches and heat-treats. At the time, a method for producing a core-sheath type composite fiber satisfying (7) to (11) as spinning conditions.
(7) Spinning temperature: Tmb + 5 ° C. to Tmb + 40 ° C.
(8) Base depth: 0.01 to 0.15 m
(9) Discharge linear velocity: 1 to 20 m / min (10) Heat treatment temperature: 100 to 200 ° C.
(11) Stretch ratio: 1.5-6 times