JP2008106410A - Crimped yarn and fiber structure using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aliphatic polyester crimped yarn providing a fiber structure not only excellent in abrasion resistance, but also excellent in peeling resistance of core sheath interface, free from change in appearance, having high quality appearance and excellent in endurance, and to provide the fiber structure composed of the crimped yarn. <P>SOLUTION: The crimped yarn is composed of a core-sheath composite fiber, wherein a core component is composed of an aliphatic polyester resin (A) and a sheath component is composed of a thermoplastic polyamide resin (B) and the crimped yarn has the following physical properties of (1) 1.5-3.0 cN/dtex strength, (2) 5-40 dtex single fiber fineness and (3) ≤6% boiling water shrinkage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a crimped yarn comprising a core-sheath composite fiber in which the core component of a single fiber includes an aliphatic polyester resin and the single fiber sheath component includes a thermoplastic polyamide resin.

  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 because they have low mechanical properties and low heat resistance and high production 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, curtains and carpets, and vehicle interiors. Applications to industrial and industrial materials are expected. In particular, the use of carpets for vehicle interiors and interiors is large, and if it can be used for such purposes, a large amount of fibers can be replaced with non-petroleum-derived materials. In other words, the use of aliphatic polyester resins typified by polylactic acid as much as possible for large-scale applications such as those mentioned above, replacing petroleum-derived materials with non-petroleum-derived materials, depleting petroleum resources, and global warming There is a possibility that this problem can be eased.

  At this time, in order to use aliphatic polyesters such as polylactic acid in the above-mentioned clothing and industrial material uses, it has at least the same characteristics as synthetic fibers made of general-purpose resins such as conventional polyesters and polyamides. Required. And the synthetic fiber used for the above-mentioned uses occupies most of the crimped yarn having a soft and bulging feeling rather than the uncrimped yarn, and the crimped yarn has the same characteristics as the conventional synthetic fiber. If fibers such as polylactic acid can be created, significant market expansion can be expected.

  However, aliphatic polyesters, especially polylactic acid, have a low molecular interaction, so that when an external force is applied, the fiber breaks and is easy to scrape, that is, it has low wear resistance and poor durability. It becomes.

  For example, polylactic acid fibers with low wear resistance can easily undergo color transfer due to abrasion or the like even in applications where a relatively low external force is applied, such as clothing, and in severe cases the fibers become fibrillated and become white. Deterioration of blur quality is remarkable. In addition, it has been found that problems such as excessive skin irritation are likely to occur, and the practical durability is poor. Even in applications where relatively weak rubbing is applied, such as clothing, aliphatic polyester fibers such as polylactic acid, which have wear resistance problems, are of course used for carpets that require even higher wear resistance. There were restrictions.

  In particular, polylactic acid has low crystallinity and low interaction between crystal phases or between a crystal phase and an amorphous phase. This is because the crystal is composed of a helical structure having a carbonyl group inside. For this reason, even if heat treatment is performed in the drawing process, crimping process, dyeing process, etc. to form a crystalline phase inside the fiber, the internal structure of the fiber is difficult to be fixed, and the molecular chain of the amorphous phase is not changed over time. It has been found that the structure easily changes (molecular chains arranged in the fiber axis direction change into disordered molecular chain arrangement). In particular, when the crimped yarn is used, the above-described change in the structure of the amorphous phase has a problem that the crimp is likely to be loosened with time (the fastness of crimp is low). This change with time occurs in all of storage in a package form, high-order processing steps, product use, and the like, and it has been difficult to maintain high crimp characteristics.

  That is, in order to apply aliphatic polyester, particularly polylactic acid fiber, to a large-scale use such as carpet use, a crimped yarn excellent in abrasion resistance and crimp fastness has been desired.

  For example, a crimped yarn for carpet composed of a single component of polylactic acid has been proposed (see Patent Document 1). However, when the crimped yarn is used for an application that receives a particularly high external force intermittently, such as a carpet for an automobile interior, polylactic acid is scraped, and in severe cases, a hole may be formed. Moreover, the crimp of the crimped yarn is gradually lost over time, and the pile falls easily due to an external force. When the pile collapsed, the polylactic acid scraped invaded from the pile root, and the wear resistance tended to deteriorate over time. These mean that the product life is short, which is a drawback in product development.

  On the other hand, the composite fiber which improved abrasion resistance by arrange | positioning polyamide with high abrasion resistance to a sheath component is disclosed (patent documents 2-3). Certainly, by covering the aliphatic polyester with the polyamide of the sheath component, it is possible to suppress the fiber scraping. However, in the case of a composite fiber, the external force concentrates on the interface between the core component and the sheath component (hereinafter referred to as the core-sheath interface) with weak adhesiveness during the high-order processing step or product use, and the core-sheath interface Peels off and causes a new problem of appearance change (white blurring). When peeling of the core-sheath interface occurs, it propagates in the longitudinal direction of the fiber, and some white streaky defects are scattered. This is a drawback particularly when the appearance is emphasized, that is, when it is used for an application touching the human eye. Once the core-sheath interface peels off, the sheath component cracks due to wear of the core component and the sheath component (hereinafter referred to as sheath crack), and the exposed aliphatic polyester can be easily scraped to reduce wear resistance. There was a problem that was easy to do.

  For example, Patent Document 2 proposes an uncrimped composite fiber that can be used for industrial material applications such as fishing nets by having polyamide 6 as a sheath component and having a specific total fineness and a specific strength. Has been. However, since the affinity between the aliphatic polyester and the polyamide is low, the adhesion at the core-sheath interface is insufficient, and this is a technique in which the external appearance easily causes interfacial peeling and changes in appearance. For this reason, although it can be applied to uses such as fishing nets, it cannot be applied to uses such as carpets that require severe changes in appearance.

Further, Patent Document 3 discloses a composite fiber having improved wear resistance by having a thermoplastic polyamide having a specific thickness as a sheath component. The composite fiber exhibits a sufficient effect in applications where only relatively low abrasion is applied, such as clothing. However, since the affinity between aliphatic polyester and polyamide is still low, in applications where a high external force is applied intermittently, such as carpets, it is a technique that easily causes interfacial peeling and changes in appearance. Patent Document 3 discloses a crimped yarn (false twisted yarn) using the composite fiber, but the crimped yarn made of the composite fiber has a peeling at the core-sheath interface more than the uncrimped yarn. It turned out to be easy to occur. Further, the peel resistance tended to be deteriorated with the aging of the aliphatic polyester. That is, the composite fiber in which polyamide is disposed as a sheath component has a drawback that when it is a crimped yarn, it is excellent in abrasion resistance but is insufficient in peeling resistance and easily changes in the appearance of the product.
JP 2002-180340 A (Claims) JP-A-2004-197276 (Claims) JP 2004-36035 A (Claims)

  The present invention solves the above-mentioned problems, and not only has excellent abrasion resistance, but also excellent in resistance to peeling at the core-sheath interface, has no change in appearance, and provides a high-quality and durable fiber structure. It is an object of the present invention to provide a polyester crimped yarn and a fiber structure comprising the same.

  In crimped yarns using the composite fiber, the inventors of the present invention have made extensive studies on the relationship between the peeling phenomenon at the core-sheath interface, the form of the crimped yarn, the core component constituting the crimped yarn, and the fiber structure of the sheath component. As a result, it has been found that the crimped yarn using the composite fiber has a specific fiber structure, and therefore, the peeling of the core-sheath interface can be suppressed for the first time, and the present invention has been completed. The present inventors have also found that the crimped yarn is a crimped yarn that achieves high wear resistance and fastness that has been a problem of conventional crimped yarns made of aliphatic polyester. Furthermore, the fiber structure using the crimped yarn has excellent durability that maintains its high quality over a long period of time without causing a change in appearance even when a high external force is applied.

That is, the present invention is a crimped yarn composed of a core-sheath type composite fiber in which the core component is made of an aliphatic polyester resin (A) and the sheath component is made of a thermoplastic polyamide resin (B). ) To (3), and a fiber structure characterized by containing the crimped yarn at least in part.
(1) Strength: 1.5 to 3.0 cN / dtex
(2) Single fiber fineness: 5 to 40 dtex
(3) Boiling: 6% or less.

  In addition, the present invention uses a direct spinning / drawing / crimping apparatus and discharges the aliphatic polyester resin (A) as a core component and the thermoplastic polyamide resin (B) as a sheath component at a nozzle discharge hole. To form a spun yarn, stretch the spun yarn at a total draw ratio of 2 to 5 times, heat set the final roll temperature after drawing to 160 to 220 ° C., and then compress the air stuffer A method for producing a crimped yarn, wherein the crimping process is performed by a processing apparatus.

  According to the present invention, even if an external force is applied, the core-sheath interface does not peel off, and a crimped yarn having no change in appearance and a fiber structure composed thereof are obtained. The crimped yarn is excellent in wear resistance, can be made into a crimped yarn having high crimp and high fastness of crimp, and is optimal for use in general clothing and industrial materials. It is possible to provide a crimped yarn that can be suitably used for an application that requires extremely high wear resistance, such as a carpet application for an automobile interior, and a fiber structure using the crimped yarn.

  The crimped yarn of the present invention is generally known as false twisted yarn, bimetal crimped yarn, mechanical crimped yarn, BCF yarn (BCF: bulked continuous filament, BCF yarn is air stuffer crimped yarn) And the like, and is a fiber having bulkiness due to the bending of single fibers or the entanglement of single fibers. The crimped yarn of the present invention may remain as a long fiber, or the obtained crimped yarn may be cut into an appropriate length and treated as a short fiber.

  The crimped yarn of the present invention has a form in which single fibers are bent in a loop shape in irregular directions, the amplitude of the loop is irregular, there is no periodicity, and the single fibers are entangled with each other. Therefore, it is preferable because the external force is easily dispersed and the peel resistance at the core-sheath interface can be dramatically improved. Such a random crimped form is easy to be formed by an air jet stuffer crimping apparatus, which will be described later, and is preferably a crimped yarn generally referred to as a BCF yarn. The BCF yarn does not have an excessively bent portion, has not only high bulkiness, but also has a characteristic of lower residual torque compared to false twisted yarn, etc. When the resulting fiber product is abraded, the external force is dispersed in each single fiber and is not easily concentrated locally, so that the peel resistance at the core-sheath interface can be improved.

  The crimped yarn of the present invention will be described with reference to photographs of fiber shapes in FIGS. FIG. 1 is a photograph of an embodiment of the BCF yarn of the present invention placed on black paper in a multifilament state and observed from above, and FIG. It is the photograph which it placed on and observed from the upper surface (both magnification is 1 time). As apparent from FIG. 1, the single fibers have loops formed in random directions, and have a crimped form in which two or more single fibers are intertwined. Further, as apparent from FIG. 2, the amplitude and period of the loop of the single fiber is irregular.

  A BCF yarn is a crimped yarn obtained by supplying a fiber into an air jet stuffer crimping apparatus by overfeed and obtained by a turbulent flow effect of a heating fluid (steam, air, etc.). A crimped yarn having an irregular loop-like crimped shape. Details are described in detail in Chapter 1 (pages 25-39) of “Filament Processing Technology Manual (Volume 2)” edited by the Japan Textile Machinery Society.

  In order to improve the peel resistance at the core-sheath interface to a level that can be applied to carpet applications where high external force is applied intermittently, the core-sheath composite fiber needs to have a specific fiber structure. Thereby, the peel resistance is remarkably improved, and the excellent peel resistance is maintained for a long time.

  As a result of earnestly examining the peeling phenomenon of the core-sheath interface of the crimped yarn using the core-sheath composite fiber, the present inventors have found that each of the core component and the sheath component is required to improve the peel resistance of the crimped yarn. Has a low degree of orientation of the amorphous phase and a high degree of crystallinity in each of the core component and the sheath component, that is, a two-phase structure of a crystalline phase and a non-oriented amorphous phase in each of the core component and the sheath component It has been found that the peel resistance of crimped yarns using core-sheath composite fibers can be remarkably improved by having First, the present inventors examined factors that tend to reduce the peel resistance of crimped yarns. And it grasped that the factor originates in the molecular orientation of the core component adjacent to a core-sheath interface and a sheath component becoming high easily compared with another area | region. Due to the high molecular orientation of each component adjacent to the core-sheath interface, the core-sheath interface of the crimped yarn tends to have residual stress, and when external force is applied, the interface peels off and tries to release the stress. There was found.

  It is unclear what causes the molecular orientation of the core component and sheath component adjacent to the core-sheath interface of the crimped yarn to be higher than in other regions, but the core component and sheath component are probably heat-shrinked during crimping. It is presumed that this is because an excessive strain is applied at the core-sheath interface. In other words, the thermal contraction of the fiber occurs by relaxing the molecular orientation of the amorphous phase in each of the core component and the sheath component, but at this time, in the case of the core-sheath type composite fiber composed of components different from each other, Usually, both components have a difference in heat shrink characteristics. Due to the difference in heat shrinkage characteristics, each component has its own heat shrinkage suppressed or promoted by other components. The molecular chain of the core component and the sheath component adjacent to the core-sheath interface undergoes unreasonable distortion when transferring heat shrinkage to each other, and as a result, the molecular orientation is not relaxed sufficiently, It is estimated that it remains in an unstable state. Residual stress is generated at the core-sheath interface due to the molecular motion of the molecular chains in such an unstable orientation state to relax the orientation. When an external force is applied, the residual stress is released by interfacial peeling.

  In crimped yarns such as false twisted yarns and mechanical crimped yarns, the molecular orientation of the core and sheath components adjacent to the core-sheath interface is likely to be high, and residual stress is generated at the core-sheath interface. It may be easy to peel off. On the other hand, when a multifilament made of a core-sheath type composite fiber is used as a BCF yarn, unlike the other processes as described above, the generation of residual stress at the core-sheath interface is greatly suppressed, and interface peeling is performed. It was found that an internal structure that does not easily occur can be formed. Although the reason for this is not necessarily clear, in the air jet stuffer crimping process, due to the turbulent flow effect of the heating fluid, the core component and the sheath component of each single fiber are combined with the melting point (Tmb) of the thermoplastic polyamide resin (B). ) It can be heated to the vicinity uniformly and in a short time, and at the same time, it is heat-shrinked in a non-tensioned state, and is immediately quenched with a cooling roll, so that the molecular orientation of the amorphous phase is sufficient even in the region adjacent to the core-sheath interface. It can be relaxed, and it is estimated that the history due to the difference in heat shrinkage characteristics of each component hardly remains. The air stuffer crimping method will be described in detail in the manufacturing method described later.

  Residual stress at the core-sheath interface is relaxed due to the high-order processing steps such as dyeing and changes over time during product use due to unstable core chains adjacent to the core-sheath interface and unstable molecular chains in the orientation state of the sheath component. It is also stored when you do. In particular, the aliphatic polyester (A), which is a core component, tends to relax the molecular orientation of the amorphous phase not only when exposed to heat but also with time. For this reason, residual stress is easily generated at the core-sheath interface, and the interface is easily peeled off. That is, the lower the molecular orientation of the core component and sheath component of the crimped yarn, the better the peel resistance. Further, the more the crystalline phase is present in the core component and the sheath component, the more the relaxation motion of the molecular chain in the amorphous phase can be restrained, and therefore the better the peeling resistance, the better.

  The fiber structure of the crimped yarn is closely related to the physical properties of the crimped yarn, and the crimped yarn of the present invention is achieved by having a specific strength, boiling point, and single fiber fineness.

  The strength of the crimped yarn tends to increase as the degree of orientation of the amorphous phase inside the fiber increases. And if it is a crimped yarn composed of a normal single component, the strength is preferably as high as possible in terms of processability and durability during use of the product, but the core-sheath type composite fiber of the present invention is used. The crimped yarn is required to have a strength of 3.0 cN / dtex or less because the lower the degree of orientation of the amorphous phase, the better the peel resistance. By setting the strength of the crimped yarn of the present invention to 3.0 cN / dtex or less, the degree of orientation of the amorphous phase inside the fiber is sufficiently low, residual stress hardly occurs at the core-sheath interface, and the peel resistance is improved. It is preferable because it is an excellent crimped yarn. The strength is preferably 2.9 cN / dtex or less, more preferably 2.8 cN / dtex or less, in terms of providing a crimped yarn having more excellent peel resistance. 2.7 cN / dtex or less Even more preferred. On the other hand, if the strength is too low, it may be inferior in yarn-making properties, high-order processing process passability, and durability as a product. Therefore, the strength needs to be 1.5 cN / dtex or more, preferably 1.6 cN / dtex or more, more preferably 1.7 cN / dtex or more, and 1.8 cN / dtex or more. More preferably. The strength can be measured by the technique shown in the examples.

  In boiling water treatment, the molecular orientation of the amorphous phase is relaxed and the fibers shrink. At this time, the crystal phase present in the fiber acts as a restraint point and suppresses relaxation of the amorphous phase. That is, the boiling yield of the crimped yarn is lower as the degree of orientation of the amorphous phase inside the fiber is lower and the degree of crystallinity is higher. That is, the lower the yield of the crimped yarn of the present invention, the lower the degree of orientation of the amorphous phase inside the fiber and the higher the degree of crystallinity. preferable. The boiling yield can be measured by the method shown in the Examples, and can be calculated by measuring the change in the length of the crimped yarn before and after the crimped yarn is treated with boiling water in a free state. The crimped yarn of the present invention is required to have a boiling yield of 6% or less. The boiling point is preferably 5.5% or less, more preferably 5% or less, and even more preferably 4.5% or less in terms of a crimped yarn having more excellent peel resistance. 4% or less is particularly preferable. The lower the boiling yield, the better. The most preferred is 0 to 3%. The boiling yield may ideally be zero.

  The crimped yarn of the present invention needs to have a single fiber fineness of 5 to 40 dtex. When the single fiber fineness is 40 dtex or less, the fibers are rapidly heated in the crimping process, and the inside of the cross section of the single fiber is uniformly heated. Therefore, the core component adjacent to the core-sheath interface, the molecule of the sheath component The chain is not easily subjected to excessive strain, residual stress is hardly generated at the core-sheath interface, and the peel resistance is excellent. At the same time, since crystallization is likely to occur, it is preferable because the fiber structure is fixed and the peel resistance can be maintained for a long time even after the dyeing process and after aging. The finer the single fiber fineness, the lower the molecular orientation of the amorphous phase and the higher the degree of crystallinity, that is, the better the peel resistance. Is more preferably 33 dtex or less, and particularly preferably 30 dtex or less. However, on the other hand, if the single fiber fineness is excessively thin, it is easy to form a two-phase structure of a crystalline phase and a random amorphous phase in the crimping process, but stretch tension or crimp applied in the process of extending the crimp later. The crimped yarn is stretched again by the winding tension applied in the yarn winding process or the tension applied in the high-order processing process, and an excessive distortion tends to occur at the core-sheath interface. For this reason, the single fiber fineness needs to be 5 dtex or more. The single fiber fineness is preferably 6 dtex or more, more preferably 7 dtex or more, still more preferably 8 dtex or more, and 9 dtex or more in that the crimped yarn has more excellent peel resistance. Is particularly preferred. The single fiber fineness can be measured by the technique shown in the examples. That is, it can be calculated by measuring the fineness of the crimped yarn comprising the multifilament of the present invention and dividing the fineness by the number of filaments.

  In the present invention, as described above, it is inevitable in a crimped yarn composed of a core-sheath composite fiber in which the core component is made of the aliphatic polyester resin (A) and the sheath component is made of the thermoplastic polyamide resin (B). (1) Strength: 1.5-3.0 cN / dtex, (2) Single fiber fineness: 5-40 dtex, (3) Boiling yield: 6% or less, resulting in high crystallinity. The crimped yarn having a fiber structure in which the molecular orientation is suppressed, and thereby the generation of distortion and residual stress at the core-sheath interface can be synergistically suppressed. Is the most appropriate representation. And the crimped yarn of this invention can be manufactured with the method of this invention mentioned later.

  In the crimped yarn of the present invention, the core component needs to be composed of an aliphatic polyester resin (A) (hereinafter referred to as component A). The core component consisting of component A is defined as 90% by weight or more of the core component is component A. By containing more component A in the core component, it becomes a material with a further reduced environmental load, and is preferably 93% by weight or more, and more preferably 95% by weight or more.

  The aliphatic polyester resin (A) referred to in the present invention refers to a polymer in which aliphatic alkyl chains are linked by ester bonds. In general, the aliphatic polyester resin (A) often has low crystallinity. As described above, when the crystallinity is low, the peel resistance of the crimped yarn may deteriorate over time. Therefore, the aliphatic polyester resin (A) used in the present invention is preferably crystalline, and more preferably has a melting point of 150 ° C. or higher and 230 ° C. or lower.

  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 melting peak has a heat capacity of 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. Since the aliphatic polyester resin (A) used in the present invention has crystallinity, the fiber structure of the aliphatic polyester resin (A) is easily fixed. Then, the relaxation of the orientation of the amorphous phase due to the change with time of component A can be suppressed, the generation of residual stress at the core-sheath interface can be suppressed for a long time, and the peel resistance is excellent, which is preferable.

  Examples of the aliphatic polyester resin (A) used in the present invention include polylactic acid, polyhydroxybutyrate, polybutylene succinate, polyglycolic acid, polycaprolactone, and the like. 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 above polylactic _{acid, - (O-CHCH 3 -CO} ) n - is a polymer as a repeating unit, and refers to those obtained by polymerizing lactic acid oligomers, such as lactic acid or 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. The melting point is preferably 150 ° C. or higher from the viewpoint of heat resistance of the fiber and maintaining the peel resistance over a long period of time. For this reason, the D-form fraction in poly-L lactic acid is preferably 10% by weight or less, preferably 5% by weight or less, and preferably 3% by 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. These low molecular weight residues are dirt on the heating roll and heating plate during stretching and heat treatment, dirt inside the heating nozzle during crimping, Or it becomes a cause which induces dyeing abnormalities, such as dyed spots in a dyeing process. In addition, the hydrolysis of fibers and fiber molded products is promoted, and the durability is lowered. Therefore, the amount of residual lactide in polylactic acid is preferably 0.3% by weight or less, more preferably 0.1% by weight or less, and still more preferably 0.03% by weight or less.

  In addition, the aliphatic polyester resin (A) may be obtained by copolymerizing components other than lactic acid, for example, within a range not impairing 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 UV 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 moldability and stretchability are lowered as described above, and thus the passability in the production process may be deteriorated. 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 said weight average molecular weight is the value calculated | required by gel permeation chromatography (GPC) using the method as described in an Example, and calculated | required in polystyrene conversion.

  The production method of polylactic acid preferably used for the aliphatic polyester resin (A) of the present invention is not particularly limited. 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 ( JP-A-6-65360), a method of copolymerizing and transesterifying at least two kinds of homopolymers in the presence of a polymerization catalyst (see JP-A-7-173266), and lactic acid once. An indirect polymerization method (see US Pat. No. 2,703,316) in which ring-opening polymerization is performed after dehydration to form a cyclic dimer can be mentioned. The higher the content of component A, the higher the content of component A (weight% of component A with respect to the total weight of the fiber). 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 peel resistance, abrasion resistance, and crimp fastness. 70% by weight or less is particularly preferable. The content of component A of the crimped yarn (% by weight of component A with respect to the total fiber weight) can be calculated by the method described in the examples. That is, the difference between the weight of the fiber after eluting only component A from the crimped yarn and the weight of the original crimped yarn is regarded as the weight of component A, and the difference in the weight is the weight of the original crimped yarn. It is calculated by dividing by.

  The crimped yarn of the present invention requires that the sheath component is made of thermoplastic polyamide (B) (hereinafter abbreviated as component B). Having the thermoplastic polyamide (B) as the sheath component is preferable because the surface of the fiber is formed of polyamide and the wear resistance is dramatically increased. Here, that the sheath component is composed of component B is defined as 90% by weight or more of the sheath component is component B. It is preferable that the sheath component contains a larger amount of Component B because the material is more excellent in wear resistance and heat resistance, more preferably 93% by weight or more, and still more preferably 95% by weight or more. 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 polycaproamide (nylon 6). ), Polyhexamethylene adipamide (nylon 66), polypentamethylene adipamide (nylon 56), polyundecanamide (nylon 11), polydodecanamide (nylon 12), polyhexamethylene sebamide (nylon 610) ), Polypentamethylene sebacamide (nylon 510), and the like.

  In addition, when the aliphatic polyester resin (A) is polylactic acid, for the purpose of increasing the affinity at the core-sheath interface and increasing the adhesion at the core-sheath interface to increase the peel resistance, Nylon 11, nylon 12, nylon 610, and nylon 510 are also preferably used by reducing the cohesiveness between the molecular chains, that is, increasing the methylene chain length. Among them, it is preferable to use a thermoplastic polyamide resin composed of a non-petroleum-derived monomer from the viewpoint of providing a material for reducing environmental impact, and an enzymatic method (decarboxylation) from sebacic acid obtained from castor oil or lysine derived from sugarcane. Nylon 610, nylon 510 and nylon 56 containing 1,5-pentamethylenediamine obtained in (Reaction) as a monomer are also preferably used. Nylon 510 is obtained, for example, by the method described in JP-A No. 2003-292614, and nylon 56 is obtained, for example, by the method described in JP-A No. 2003-292612. Component B may be a homopolymer or a copolymer.

  The melting point of the thermoplastic polyamide resin (B) is preferably 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 the thermoplastic polyamide resin (B) used as the sheath component is preferably 250 ° C. or lower. More preferably, the melting point of the thermoplastic polyamide resin (B) is 230 ° C. or less. 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 the thermoplastic polyamide resin (B) is preferably 150 ° C. or higher. More preferably, the melting point of the thermoplastic polyamide resin (B) is 180 ° C. or higher. As described above, the thermoplastic polyamide resin (B) may be a copolymerized polymer, but the crimped yarn of the present invention has a higher processing step or changes over time when the product is used as it contains more crystalline phases. Also, the relaxation of the orientation of the amorphous phase can be suppressed, residual stress hardly occurs at the core-sheath interface, and it is preferable because of excellent peeling resistance. For this reason, it is preferable that the thermoplastic polyamide resin (B) has crystallinity. 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 higher the melting point of the thermoplastic polyamide resin (B) is in the above range and the higher the crystallinity, the more preferable the fiber of the present invention is because of excellent peeling resistance, abrasion resistance, and heat resistance. As the thermoplastic polyamide resin (B), 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 not only has higher crystallinity and higher peel resistance, but also is inexpensive and is not restricted by applications and can be used widely and widely.

Preferably the melt viscosity of the thermoplastic polyamide resin (B) (ηb) is 10~300Pa · ^{sec -1,} more preferably 20~250Pa · ^{sec -1,} is 30~200Pa · ^{sec -1} More preferably. By increasing the melt viscosity of the thermoplastic polyamide resin (B), the temperature of the fiber can be controlled without causing fusion between single fibers in the heat treatment after stretching and the crimping process. ) Near the melting point (Tmb). As a result, the amorphous phase molecular chain in the thermoplastic polyamide resin (B) is easily bipolarized between the crystallized molecular chain and the molecular chain that is randomly arranged by relaxing the orientation, and is resistant to peeling. It is preferable because it is excellent. On the other hand, the melt viscosity of the thermoplastic polyamide resin (B) is suppressed to an appropriate height from the viewpoint of suppressing the core-sheath complex abnormality in the spinning process and uniformly covering the sheath component in the fiber cross section and the longitudinal direction of the fiber. It is preferable. From the above, the melt viscosity of the thermoplastic polyamide resin (B) is preferably in the above range. In addition, although the detail of the measuring method of melt viscosity (eta) b is mentioned later, it is melt viscosity when measured with the measurement temperature of 240 degreeC and the shear rate of 1216 sec- ¹ . Component B may also contain additives such as particles, flame retardants, antistatic agents, heat stabilizers and the like.

  Since the aliphatic polyester (A) of the present invention and the thermoplastic polyamide (B) usually hardly react (ester-amide exchange hardly occurs), the adhesion at the core-sheath interface formed by the two polymers is increased. For this purpose, it is also preferable to add a compatibilizing agent (C) (hereinafter sometimes abbreviated as component C). Component C is not particularly limited as long as it improves the interfacial adhesion between Component A and Component B, but when it is a compound having two or more active hydrogen reactive groups in one molecule, It is preferable because the adhesion at the core-sheath interface can be dramatically improved. A compound having two or more active hydrogen reactive groups in one molecule is added to component A and / or component B, melt blended, and spinning is performed. Since the reaction with the components takes a crosslinked structure, the peeling phenomenon at the core-sheath interface can be suppressed.

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

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

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

  In addition, a polymer containing a glycidyl methacrylate group in the main chain and graft-polymerized with polymethyl methacrylate as the side chain is excellent in compatibility with Component A and rich in reactivity with Component A and Component B. Therefore, it is preferable. Examples of the compound having such a structure include “Modiper A4200” manufactured by Nippon Oil & Fats Co., Ltd., which is preferably used.

  Of the components C that can be used in the present invention, compounds having an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, and a maleic anhydride group can be used in the same manner. Among the above, those having a carbodiimide group are more preferable because of extremely excellent low-temperature reactivity. For example, examples of the carbodiimide compound include diphenylcarbodiimide, di-cyclohexylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, diisopropylcarbodiimide, dioctyldecylcarbodiimide, di-o-toluylcarbodiimide, di-p-toluylcarbodiimide, di- p-nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p-hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di -2,5-dichlorophenylcarbodiimide, p-phenylene-bis-o-toluylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, p-phene Len-bis-di-p-chlorophenylcarbodiimide, 2,6,2 ', 6'-tetraisopropyldiphenylcarbodiimide, hexamethylene-bis-cyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, ethylene-bis-dicyclohexylcarbodiimide N, N′-di-o-triylcarbodiimide, N, N′-diphenylcarbodiimide, N, N′-dioctyldecylcarbodiimide, N, N′-di-2,6-dimethylphenylcarbodiimide, N-triyl- N′-cyclohexylcarbodiimide, N, N′-di-2,6-diisopropylphenylcarbodiimide, N, N′-di-2,6-di-tert-butylphenylcarbodiimide, N-toluyl-N′-phenylcarbodiimide, N, N'-Di-p- Trophenylcarbodiimide, N, N′-di-p-aminophenylcarbodiimide, N, N′-di-p-hydroxyphenylcarbodiimide, N, N′-di-cyclohexylcarbodiimide, N, N′-di-p-toluyl Carbodiimide, N, N′-benzylcarbodiimide, N-octadecyl-N′-phenylcarbodiimide, N-benzyl-N′-phenylcarbodiimide, N-octadecyl-N′-tolylcarbodiimide, N-cyclohexyl-N′-tolylcarbodiimide, N-phenyl-N'-tolylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, N, N'-di-o-ethylphenylcarbodiimide, N, N'-di-p-ethylphenylcarbodiimide, N, N ' -Di-o-isopropylphenylcarbodiimide, , N'-di-p-isopropylphenylcarbodiimide, N, N'-di-o-isobutylphenylcarbodiimide, N, N'-di-p-isobutylphenylcarbodiimide, N, N'-di-2,6-diethyl Phenylcarbodiimide, N, N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N, N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N, N'-di-2,4,6- Mono- or dicarbodiimide compounds such as trimethylphenylcarbodiimide, N, N′-di-2,4,6-triisopropylphenylcarbodiimide, N, N′-di-2,4,6-triisobutylphenylcarbodiimide, poly (1 , 6-Hexamethylenecarbodiimide), poly (4,4'-methylenebiscyclohexylca) Bodiimide), poly (1,3-cyclohexylenecarbodiimide), poly (1,4-cyclohexylenecarbodiimide), poly (4,4'-diphenylmethanecarbodiimide), poly (3,3'-dimethyl-4,4'- Diphenylmethanecarbodiimide), poly (naphthylene carbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (tolylcarbodiimide), poly (diisopropylcarbodiimide), poly (methyl-diisopropylphenylenecarbodiimide), poly ( And polycarbodiimides such as triethylphenylenecarbodiimide) and poly (triisopropylphenylenecarbodiimide). Among them, polymers of N, N′-di-2,6-diisopropylphenylcarbodiimide and 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide are mentioned, and among these, the heat resistance is high and the thermal decomposition is difficult, and the reaction In particular, “Carbodilite HMV-8CA” manufactured by Nisshinbo Co., Ltd., “Carbodilite HMV-8PI” manufactured by Nisshinbo Co., Ltd., and “Carbodilite LA-1” manufactured by Nisshinbo Co., Ltd. are particularly preferably used. . Further, the two or more active hydrogen reactive groups may be the same reactive group or different ones, but the same reactive group is preferable in order to control the reactivity.

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

  Moreover, since the compound used as Component C is melt-spun at 200 to 250 ° C. in producing the fiber of the present invention, high heat resistance that can withstand it is required. Therefore, it is preferable that the thermal weight loss rate at the 200 ° C. arrival point by thermogravimetry (TG) measurement is 3% or less. If the thermal weight loss rate exceeds 3%, the pyrolyzed product bleeds out during spinning and soils the spinneret and spinning device, so that the spinnability deteriorates and the working environment tends to deteriorate due to fuming of pyrolysis gas. There may be a problem in the point. More preferably, the heat loss rate is 2% or less, and further preferably 1% or less. The 200 ° C. heat loss rate is measured by measuring the weight loss rate at 200 ° C. by raising the temperature from normal temperature (10-30 ° C.) to 300 ° C. at a rate of 10 ° C./min. It is what I have sought.

  The amount of component C added can be appropriately determined according to the equivalent weight per unit weight of the reactive group of the compound used, the dispersibility and reactivity at the time of melting, and the content of component A, but it suppresses peeling at the core-sheath interface. In view of this, it is preferable that the content is 0.005% by weight or more with respect to the total amount (100% by weight) of Component A, Component B, and Component C. More preferably, it is 0.02 weight% or more, More preferably, it is 0.1 weight% or more. If the amount of component C added is too small, the reaction amount at the core-sheath interface is small, and the effect of improving the adhesion at the core-sheath interface may be limited. On the other hand, the amount of component C added is preferably 5% by weight or less in order for component C to exhibit performance without impairing the properties of component A and component B, which are the base material of the fiber, and the spinning performance. % Or less is more preferable. More preferably, it is 1 weight% or less.

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

  The 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 unlikely to undergo 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 crimped yarn of the present invention preferably has a core / sheath ratio (weight ratio) of 10/90 to 65/35. Since the crimped yarn of the present invention is a material that reduces the environmental load, it is preferable that the ratio of the core component is high. In addition, the area of the core-sheath interface increases as the ratio of the core component increases. However, when the ratio of the core component is high, since the crystallinity is low and many components A that are likely to change with time are contained, the core changes with time. Residual stress tends to occur at the sheath interface, and the peel resistance tends to deteriorate. That is, in order to improve the peel resistance, it is preferable that the area of the core-sheath interface per unit volume of the core component is large, and in this respect, the ratio of the core component is preferably low. Furthermore, when the ratio of the sheath component is increased, there is an advantage that the fastness of crimping is increased and the crimping is difficult to set. Therefore, the core-sheath ratio is preferably in the above range, more preferably from 10/90 to 50/50, and particularly preferably from 10/90 to 45/55.

The core-sheath ratio of the present invention can be calculated by calculating the ratio of the core component and the sheath component relative to the sum of the weight of the core component and the sheath component when subjected to melt spinning as 100. However, when the weight ratio between the core component and the sheath component at the time of manufacture is unknown, it can be calculated simply using the following formula. That is, the core component of the crimped yarn of the present invention may contain component A and other minor components, and the sheath component may contain component B and other minor components. It can be considered that the component consists essentially of component A and the sheath component consists only of component B, and the core-sheath ratio can be calculated as the weight ratio of the core component to the sheath component. First, the cross-sectional slice of the crimped yarn is observed with a transmission electron microscope (TEM) at a magnification of 4,000, and the total area (Aa) of the region constituting the core component and the total area (Aa) of the region constituting the sheath component ( Ab). 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.
Core-sheath ratio = weight ratio of core component / weight ratio of sheath component weight ratio of core component = [(Aa × 1.26) / (Aa × 1.26 + Ab × 1.14)] × 100
Weight ratio of sheath component = [(Ab × 1.14) / (Aa × 1.26 + Ab × 1.14)] × 100.

  The cross-sectional shape of the single fiber of the crimped yarn 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 single fiber may be the same, or may differ. One embodiment of the cross-sectional shape of the single fiber of the crimped yarn of the present invention is illustrated in FIG. In FIG. 4, 23 represents component A, and 24 represents component B. FIG. 4 shows a round shape, a Y shape, and various types. Specifically, the cross-sectional shape of the single fiber of the crimped yarn of the present invention is preferably Y-type, multi-leaf type, and flat type, and particularly preferably Y-type or flat type.

  The crimped yarn of the present invention preferably has a single fiber irregularity (D3 / D4) of 1.3 to 4. The higher the degree of irregularity of the single fiber, the larger the surface area of the fiber. Therefore, in the crimping process, the fiber is rapidly heated and the inside of the cross section of the fiber is uniformly heated. Therefore, the core component adjacent to the core-sheath interface In the molecular chain of the sheath component, excessive strain is not easily applied, and the peel resistance is excellent, which is preferable. For this reason, the degree of deformity of the single fiber is preferably 1.3 or more, more preferably 1.5 or more, further preferably 1.8 or more, and particularly preferably 2.0 or more. . However, on the other hand, if the degree of irregularity is excessively high, the cross-sectional shape tends to have an acute angle portion, and external force may concentrate on the acute angle portion and wear resistance may deteriorate. In addition, there is a disadvantage in the manufacturing process that makes it difficult to uniformly coat the core component with the sheath component in the longitudinal direction. In terms of suppressing these points, the degree of irregularity is preferably 4 or less, more preferably 3.8 or less, further preferably 3.5 or less, and 3.3 or less. Particularly preferred.

  The degree of irregularity of the single fiber of the present invention is determined by observing the cross section of the single fiber by the method of the embodiment using TEM, and the ratio of the diameter D3 of the circumscribed circle and the diameter D4 of the inscribed circle (D3 / D4) ). When it is determined that the irregular cross section generally retains line symmetry and point symmetry, the inscribed circle is a circle inscribed in a curved line that outlines the cross section of the single fiber, and the circumscribed circle is the cross section of the single fiber. Is a circle circumscribing the curved curve. 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 curved line that forms the outline of the single fiber, and only exists inside the fiber. A circle having the maximum radius that can be taken in a range in which the circumference of the circle does not intersect with the curve forming the outline of the single fiber is defined as an inscribed circle. The circumscribed circle is circumscribed at least at two points in the curve showing the outline of the single fiber, exists only outside the cross section of the single fiber, and is the smallest radius that can be taken within the range where the circumference of the circumscribed circle does not intersect the outline of the single fiber A circle with a is a circumscribed circle. In the calculation of the irregularity, the irregularities were calculated and averaged at 10 cross sections obtained by cutting different portions.

  The crimped yarn of the present invention preferably has a core component irregularity (D1 / D2) of 1.3 to 4. The higher the degree of irregularity of the core component, the larger the area of the core-sheath interface per unit volume of the core component, and the better the peel resistance. For this reason, the degree of deformity of the core component is preferably 1.3 or more, more preferably 1.5 or more, further preferably 1.8 or more, and particularly preferably 2 or more. On the other hand, if the degree of deformity of the core component is too large, it may be difficult to uniformly coat the sheath component in the cross section and the longitudinal direction of the single fiber, and the peel resistance may deteriorate. For this reason, the degree of deformity of the core component is preferably 4 or less, more preferably 3.8 or less, further preferably 3.5 or less, and particularly preferably 3.3 or less.

  The degree of deformity of the core component of the present invention is determined by observing the cross section of the single fiber by the method of the example using TEM, and the ratio of the diameter D1 of the circumscribed circle of the core component to the diameter D2 of the inscribed circle of the core component ( D1 / D2). When it is determined that the core component generally retains line symmetry and point symmetry, the inscribed circle is a circle inscribed in the curved line that defines the core component in the cross section of the single fiber, and the circumscribed circle is a single fiber. Is a circle circumscribing a curve that outlines the core component in the cross section. When it is determined that the core component has a shape that does not retain line symmetry or point symmetry at all, it is inscribed at least at two points with the curve that forms the outline of the core component, and exists only inside the core component. A circle having the maximum radius that can be taken in a range in which the circumference of the inscribed circle does not intersect with the curve that forms the outline of the core component is defined as the inscribed circle. The circumscribed circle is circumscribed at least at two points in the curve showing the outline of the core component, exists only outside the outline of the core component, and has the smallest radius that can be taken within the range where the circumference of the circumscribed circle and the outline of the core component do not intersect The circle that you have is the circumscribed circle. In the calculation of the deformity of the core component, the deformities were calculated and averaged at 10 cross sections obtained by cutting different portions.

  The cross-sectional shape of a preferable crimped yarn in the present invention is illustrated. The cross-sectional shape of the core component of the single fiber constituting the crimped yarn is arbitrary, but the adhesiveness at the core-sheath interface is increased, the ratio of the core component of the crimped yarn, and the content of component A is large. In both cases, it is preferable that the cross-sectional shape of the core component is similar to the cross-sectional shape of the single fiber in terms of excellent peeling resistance. Here, the similar shape does not mean a mathematically exact similarity, for example, when the cross-sectional shape of the single fiber is Y-type, the cross-sectional shape of the core component is Y-type, and the degree of irregularity of both is different Even so, it shall be regarded as a similar shape. Of course, the crimped yarn of the present invention is not limited to the cross-sectional shape of FIG. The number of core components of the crimped yarn of the present invention is arbitrary, and the single fiber may have one core component inside or a plurality of core components. The center of gravity of the shape defined by the cross section of the single fiber and the center of gravity of the shape defined by the core component may be the same or different, but the fiber surface is uniformly coated with the sheath component. Since the wear resistance is excellent, it is preferable that the center of gravity of the shape formed by the outline of the single fiber and the center of gravity of the shape formed by the outline of the core component are the same. In the multifilament, the shape of the outline of the core component in the cross section of each single fiber may be the same or different.

  The crimped yarn of the present invention is a crimped yarn using a so-called sea-island composite fiber in which a plurality of core components are present in the cross section of a single fiber, and the core-sheath interface per unit volume of the core component This is preferable because the area is increased and the peel resistance is improved. For this reason, the core component is preferably 3 or more islands, more preferably 9 or more islands, and still more preferably 24 or more islands.

  In the crimped yarn of the present invention, the fiber surface is substantially composed of a sheath component in all the longitudinal directions in that it becomes a fiber having excellent wear resistance, and in particular, component A is not exposed to the fiber surface. Is preferred. The crimped yarn of the present invention is excellent in peel resistance, and the wear resistance is drastically improved when the fiber surface is substantially covered with a sheath component. Here, when the cross section of the single fiber is observed by the technique described in the examples that the fiber surface is substantially covered with the sheath component, the sheath component having a thickness of 0.1 μm or more is present in the entire cross section profile. It means that it is covered. And in order to improve abrasion resistance and peeling resistance, it is preferable that a sheath component is thick in all the cross sections of a fiber, and it is preferable that the minimum value of the thickness of a sheath component is 0.4 micrometer or more. The thickness is more preferably 0.7 μm or more, and further preferably 1 μm or more. In order to increase the minimum thickness of the sheath component, the core-sheath ratio, single yarn fineness, and single fiber irregularity are preferably within the above ranges, and the melt viscosity ratio of component A and component B and the spinning temperature are It is preferable to make it into the range mentioned later.

  The crimped yarn of the present invention has a higher degree of crystallinity, that is, the more the crystalline phase is included, the easier it is to suppress the orientation relaxation movement of the amorphous phase of the core component and the sheath component, and the excellent crimp resistance. Therefore, it is preferable. Further, the higher the degree of crystallinity, the better the abrasion resistance, heat resistance, fastness of dyeing and crimping, and the like, so that it is preferable. The crystallinity in the present invention can be evaluated by the sum of the heat capacities of the melting peaks of the differential calorimetric curve measured at a temperature increase rate of 16 ° C./min, and the sum of the heat capacities of the melting peaks is 50 J / g or more. It is preferably 55 J / g or more, more preferably 60 J / g or more, particularly preferably 65 J / g or more, and most preferably 70 J / g or more. In order to show such a melting peak, it is preferable to use a polymer having high crystallinity as Component A and Component B. As will be described later, in order to promote crystallization of each component, it is preferable to adjust production conditions such as a draw ratio, a heat treatment temperature after drawing, and a crimp nozzle temperature in a crimping process.

  The crimped yarn of the present invention is easily stretched while maintaining the uniformity of the molecular orientation of each component in the subsequent stretching step by uniformly aligning the core component and the sheath component in the melt spinning step. It is difficult to cause a difference in heat shrinkage characteristics between the core component and the sheath component during crimping, and it is difficult to apply excessive strain to the molecular chains adjacent to the core-sheath interface, thereby improving the peel resistance. Since the molecular orientation of the core component and the sheath component is governed by the stress applied to each component during elongation deformation, the melt viscosity (ηA) of the aliphatic polyester resin (A) and the melt viscosity of the thermoplastic polyamide resin (B) ( ηB) is preferably close, and the melt viscosity ratio (ηB / ηA), which is the ratio of the melt viscosities of component A and component B, is preferably 0.2-2. More preferably, it is 0.4-1.7, More preferably, it is 0.6-1.4.

Here the melt viscosity ηA in the present invention, ItaB a temperature 240 ° C. of the polymer used in the crimped yarn, a melt viscosity at a shear rate of ^{1216sec -1 (Pa · sec -1)} , measured by the procedure described in Example can do. When component A and component B used for the crimped yarn cannot be obtained, the relative viscosity (ηrA) of component A in the crimped yarn and the relative viscosity (ηrB) of component B in the crimped yarn are measured. By doing this, ηA and ηB can be easily obtained. As shown in the plot of FIG. 7, ηrA and ηA, and ηrB and ηB are in the relationship of the following equations, respectively.
Relationship between solution viscosity and melt viscosity of component A log (ηA) = 4.3049 × log (ηrA) Relationship between solution viscosity of component B and melt viscosity log (ηB) = 5.2705 × log (ηrB).

  Here, the relative viscosity can be measured by the method shown in the Examples. That is, using an Ostwald viscometer, component A is an o-chlorophenol solution, component B is a sulfuric acid solution, and each of the dropping times of a solution in which each component is dissolved at a specific concentration, temperature, and time and a solvent that does not dissolve each component. It is expressed by the ratio and is an index indicating the solution viscosity.

  The crimped yarn 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 and component B, the more easily the lubricant is supported on the fibers, 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 and Component B 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 seba 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 bis Examples thereof include hydroxystearic acid amide, ethylene bishydroxystearic acid amide, butylene bishydroxystearic acid amide, and hexamethylene bishydroxystearic acid amide.

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 crimped yarn comprising the core-sheath type composite fiber of the present invention includes, for example, an antioxidant and a heat stabilizer (hindered phenol type, hydroquinone type, phosphite type and substituted products thereof, copper halide, iodine compound, etc.) , Weathering agents (resorcinol, salicylate, benzotriazole, benzophenone, hindered amine, etc.), pigments (cadmium sulfide, phthalocyanine, carbon black, etc.), gloss improvers (titanium oxide, calcium carbonate, etc.), dyes (nigrosine, Aniline black, etc.), crystal nucleating agents (talc, silica, kaolin, clay, etc.), plasticizers (octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc.), antistatic agents (alkyl sulfate type anionic antistatic agents) Quaternary ammonium salt type cationic antistatic agent, polyoxyethylene Nonionic antistatic agents such as sorbitan monostearate, betaine amphoteric antistatic agents), flame retardants (hydramines such as melamine cyanurate, magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, brominated) Polystyrene, brominated polyphenylene oxide, brominated polycarbonate, brominated epoxy resin, or a combination of these brominated flame retardants and antimony trioxide).

  The crimped yarn of the present invention preferably has a higher crimp elongation after boiling water treatment, which is an index of the bulky property of the crimped yarn, in that the higher the bulky property of the crimped yarn, the better the product quality. For this reason, the crimp elongation after boiling water treatment is 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 single fiber is likely to have a bent portion, and the peel resistance may deteriorate. In this respect, the elongation after the boiling water treatment is preferably 35% or less, more preferably 33% or less, and particularly preferably 30% or less.

  The crimped yarn of the present invention is difficult to crimp in the dyeing process, high-order processing process, or long-term use after forming a fiber structure (high crimp fastness), and the volume of the product is long. It is preferable to maintain it over time. For this reason, it is an index of the fastness of crimp, and the crimp elongation after treatment with boiling water under a load of 2 mg / dtex (hereinafter referred to as the crimp elongation after treatment with boiling water under a load of 2 mg / dtex) May be simply described as “elongation rate under restraint load”) is preferably 2% or more. More preferably, it is 3% or more, still more preferably 5% or more, and particularly preferably 7% 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. The elongation rate under restraint load can be measured by the method shown in the examples.

  Moreover, when the elongation of the crimped yarn of the present invention is 15 to 70%, it is preferable because the process passability when the fiber product is made is good. A crimped yarn having such an elongation can be produced by setting the draw ratio within a preferable range in the production method described later. More preferably, it is 20-60%, More preferably, it is 30-50%.

  The crimps of the crimped yarn of the present invention are preferably small. By reducing the yarn spot, it is possible to prevent the external force from concentrating on the local area when rubbed, and this is preferable because the peel resistance can be improved. For this reason, the thread spot (Uster) (U%) (Normal) which is an index of thread spot is preferably 2.5% or less, more preferably 2.0% or less, further preferably 1.5 or less, and particularly preferably 1.0 or less. preferable. In order to reduce the yarn unevenness of the crimped yarn of the present invention, the component A and the component B having a melt viscosity ratio in the preferred range of the present invention are selected to stabilize the thinning behavior of the spinning line, By continuously performing the drawing and crimping processes in one step, the yarn unevenness can be reduced by directly drawing and crimping the undrawn yarn without changing with time.

The crimped yarn of the present invention may be subjected to an entanglement treatment as necessary, and the CF value (Coherence Factor) can be selected in the range of 3 to 30. Here, the CF value is measured under the conditions indicated by the entanglement degree of JIS L1013 (chemical fiber filament yarn test method) 7.13, the number of tests is 50 times, and the average value L (mm ) From the following formula.
CF value = 1000 / L
The crimped yarn of the present invention needs to have a single fiber fineness within a specific range, and the total fineness is not particularly limited, but it is easy to lengthen the time for the crimped yarn to stay inside the crimped nozzle. The total fineness is preferably 3000 dtex or less, more preferably 2500 dtex or less, and further preferably 2000 dtex or less. The total fineness is preferably 500 dtex or more, more preferably 600 dtex or more, and even more preferably 700 dtex or more, from the viewpoint of easily suppressing pile collapse when an external force is applied to the carpet.
The number of single fibers constituting the crimped yarn (number of filaments) can be freely selected so as to be within the range of the single fiber fineness of the present invention.

  Moreover, when using the crimped yarn 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, wear resistance is required, and clothing that is required not to change appearance, such as outdoor wear, golf wear, athletic wear, ski wear, There are women's and men's outerwear such as snowboard wear and sportswear such as pants, casual wear such as blouson, coat, winter clothes and rainwear. In addition, uniforms, comforters and mattresses, skin comforters, kotatsu comforters, cushions, baby comforters, blankets and other futons and pillows, cushions and other linings and covers, mattresses and bed pads, hospital, medical, hotel and baby Bedding materials such as sleeping bags, cradle and covers for baby strollers etc., and can be preferably used for these. And the crimped yarn of this invention which has high abrasion resistance and an external appearance change does not occur can be used 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.

  The crimped yarn of the present invention can be produced, for example, by the following method.

  Using a direct spinning / drawing / crimping apparatus, the aliphatic polyester resin (A) as the core component, the thermoplastic polyamide resin (B) as the sheath component, and the core-sheath ratio (weight ratio) 65/35 to 10/90 The melt viscosity ratio (ηB / ηA) is in the range of 0.2 to 2 when being merged at the die discharge hole, and the spinning temperature is Tmb relative to the melting point Tmb of the thermoplastic polyamide resin (B). -Tmb + 30 ° C, a spun yarn is formed at a discharge linear velocity of 1 to 20 m / min at the spout discharge hole, and 0.01 to 0.15 m vertically below the spun yarn is set as a cooling start point from the spout surface, After stretching a multifilament cooled with a gas having a wind speed of 0.3 to 1 m / second and a wind temperature of 15 to 25 ° C. from a direction perpendicular to the vertical direction of the base surface, the stretch ratio is 2 to 5 times in two stages, When crimping, the first stage When the temperature is set to 50 to 90 ° C., the second stage drawing roll is set to 90 to 150 ° C., the final roll temperature after drawing is set to 160 to 220 ° C., and is supplied to the air jet stuffer crimping apparatus. The crimping process is performed with the nozzle temperature of the apparatus being 5 to 100 ° C. higher than the final roll temperature after stretching to form a crimped yarn, and it is applied to a cooling drum and is taken up by 10 from the final roll after stretching. It is a method of winding at a speed that is -30% lower.

  That is, an aliphatic polyester resin (component A) such as poly-L lactic acid and a thermoplastic polyamide resin (component B) such as nylon 6 are dried, so that the moisture content of component A is 100 to 10 ppm and the moisture content of component B is What is 500-100 ppm is adjusted beforehand. And after melt | dissolving the component A and the component B with a separate biaxial extrusion kneader or a single screw extrusion kneader, and measuring with a separate gear pump at a core-sheath ratio (weight ratio) of 65/35 to 10/90, As the base disposed inside the spinning pack, the bases are combined as shown in FIG. 6, and component A and component B are combined and discharged to obtain a spun yarn. FIG. 6 is a schematic side sectional view showing an embodiment of a base used in the method of the present invention. The base is a base 1 (30) which is a base immediately before discharge and immediately before the base 1 and is divided into a core component and a sheath component. A base 2 (29) having a flow path is combined.

  When melting component A and component B with a kneader, it is preferable to melt component A at a temperature of the melting point (Tma) of component A to the melting point (Tma) of component A + 40 ° C., for example, component A has a melting point of 170 ° C. In the case of polylactic acid, it is preferable to melt component A in the range of 170 to 210 ° C. By melting the component A in the above range, hydrolysis of the component A having low heat resistance can be suppressed, viscosity spots in the longitudinal direction of the component A are hardly generated, spinnability is improved, and the resulting fiber is uniform. It is preferable because it is excellent. The component B is preferably melted at a temperature of the melting point (Tmb) of the component B to the melting point (Tmb) of the component B + 40 ° C. For example, when the component B is nylon 6 having a melting point of 225 ° C., 225 to 265 ° C. It is preferable to melt in the range. It is preferable to melt the component B within the above range because gelation and coloring of the component B can be suppressed.

  The spinning temperature can be determined by the melting point of component B (polyamide), and the optimum range is the melting point Tmb to Tmb + 30 ° C. of component B (for example, 225 to 255 ° C. when the melting point Tmb of component B is 225 ° C.). However, the heat resistance of component A is not so high, and when it exceeds 250 ° C. during melt storage, the physical properties tend to deteriorate rapidly. For this reason, as described above, it is preferable to select the thermoplastic polyamide resin (B) having a melting point of 250 ° C. or lower as the sheath component and to set the spinning temperature to 260 ° C. or lower.

  The discharge linear velocity at the nozzle discharge hole is preferably 1 to 20 m / min. By setting the discharge linear velocity to 20 m / min or less, a shear stress can be applied uniformly in the cross section of the single fiber, and the molecules of the core component and the sheath component can be uniformly oriented. Heat shrinkage in the crimping process is preferable because an excessive strain is not easily applied to the core-sheath interface, and the crimped yarn has excellent peel resistance. In addition, it is preferable to set the discharge linear velocity to 1 m / min or more because rapid thinning of the spinning wire can be suppressed, and the yarn forming property or the uniformity of the crimped yarn is improved. The discharge linear velocity is more preferably 2 to 15 m / min, and further preferably 3 to 12 m / sec. 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 base 1 (30) immediately before the polymer discharge shown 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.

FIG. 5 is a schematic side cross-sectional view of the bottom surface of the base for explaining the discharge hole length, hole diameter, slit length, and slit width. The slit length and slit width in the Y hole, multi-leaf hole, and flat hole are shown in FIG. In the schematic view of the shown lower face of the base, the slit length is 27 and the slit width is 28. The discharge hole length is represented by 25.
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. 5C), A (cm ² ) = 3 × slit width (cm) × slit length (cm) + (the middle triangle surrounded by the slits) ), The discharge area can be calculated, but 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 ) = The discharge area may be calculated by the equation 3 × slit width (cm) × slit length (cm).

Moreover, it is preferable that L / D which is a ratio of the hole diameter (D) and the discharge hole length (L) in a nozzle discharge hole shall be 0.6-10. By setting L / D to 10 or less, the core component is easily disposed at the center of the fiber, and this is preferable because the crimped yarn has excellent peel resistance. Further, by setting L / D to 0.6 or more, the core component and the sheath component are uniformly distributed to each hole, and the core-sheath ratio is uniform among the single fibers, so all the fibers constituting the multifilament Is preferable because it has excellent peeling resistance. More preferably, it is 0.7-8, It is further more preferable that it is 0.8-6, It is especially preferable that it is 0.9-4. In the present invention, the discharge hole length refers to the length of 25 in the cross-sectional schematic diagram of the base hole shown in FIG. 5, 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 a length of 26 in the schematic diagram of the lower surface portion of the base shown in FIG. When the discharge hole is not a round hole, the discharge area A (cm ² ) was calculated by the method described in the description of the discharge linear velocity, and the diameter when the discharge area was regarded as a circle was defined as the hole diameter.

  Thus, when the component A and the component B are merged and discharged by the die, the core-sheath ratio, the melt viscosity ratio of the component A and the component B, the melt viscosity of the component B, and the discharge linear velocity at the die discharge hole are within the above range. It is preferable to be inside because it is easy to uniformly align the molecular orientation of the core component and the sheath component in the spinning and drawing process, and the sheath component can be uniformly coated in the longitudinal direction of the fiber.

  Moreover, it is preferable to set 0.01 to 0.15 m vertically downward from the base surface as a cooling start point. Setting the cooling start point to 0.15 m or less is preferable because the spinning line is rapidly cooled and the core component and the sheath component are easily molecularly oriented uniformly. In addition, by setting the cooling start point to 0.01 m or more, the die surface is cooled and the spun yarn contains an unmelted polymer, and thus it is difficult to cause problems such as ejection failure, and the passability of the manufacturing process is increased. Therefore, it is preferable. For this reason, the cooling start point is more preferably 0.02 to 0.14 m, further preferably 0.03 to 0.13 m, and particularly preferably 0.04 to 0.12 m. In order to prevent the temperature of the base surface from being lowered, a method of actively heating the base surface by arranging a ring heater around the base surface is also preferable.

  The cooling air is blown against the spun yarn at a wind speed of 0.3 to 1 m / sec and a wind temperature of 15 to 25 ° C. from a direction perpendicular to the vertical direction of the cap surface so that the temperature of the cap surface is not lowered. Is preferred.

  In addition, the fibers of the present invention are in an undrawn yarn state, or are easily relaxed when left in a drawn yarn. If there is a time difference until drawing between undrawn yarn packages, or until crimping is performed between drawn yarn packages. If there is a time difference, the molecular orientation of the amorphous phase of the core component, which tends to cause orientation relaxation, relaxes first, and the difference in thermal shrinkage characteristics between the core component and the sheath component increases, resulting in crimping. Residual stress tends to occur at the core-sheath interface of the crimped yarn obtained by processing. Therefore, the relaxation of the molecular orientation of the amorphous phase of each component is suppressed between the spinning, drawing, and crimping processes, and in the crimping process, there is a difference between the thermal shrinkage characteristics of the core component and the sheath component. Therefore, it is preferable to perform direct spinning / stretching / crimping, in which spinning, stretching, and crimping are continuously performed in one stage. That is, after the spun yarn is taken up by a take-up roll, it is preferably stretched and heat-treated continuously without winding, and then directly crimped.

  By taking out the spun yarn, an undrawn yarn is obtained, and the drawn yarn obtained by drawing the undrawn yarn is crimped, but in order to increase the peel resistance of the crimped yarn of the present invention, In the crimping process, it is important to form a bipolar fiber structure of a crystalline phase and a random amorphous phase without causing excessive distortion at the core-sheath interface. For this purpose, it is preferable that both components are uniformly oriented in the drawn yarn before being subjected to crimping treatment. Therefore, the undrawn yarn obtained at a low spinning speed is drawn, and fiber molecules are drawn in the drawing step. It is preferable to increase the orientation. This is because if the spinning speed is increased and the molecular chains of the core component and the sheath component are oriented in the molten state, the degree of molecular orientation of each component is likely to be different, and the molecular orientation of both components is difficult to be made uniform. In the molten state, the stress applied to each component is determined according to the melt viscosity ratio of component A and component B, and the difference in stress applied to each component increases as the spinning speed increases, that is, the spinning tension increases. For this reason, it is preferable to lower the spinning speed and to uniform the degree of orientation of the core component and the sheath component in the undrawn yarn. The optimum spinning speed varies depending on the melt viscosity ratio of component A and component B and the core-sheath ratio, but by setting the spinning speed to 3000 m / min or less, the spinning tension can be kept low, and the undrawn yarn It is preferable because the degree of molecular orientation of the core component and sheath component in the inside can be made uniform. On the other hand, it is preferable to set the spinning speed to 300 m / min or more because the spinning tension becomes moderately high, the yarn swing of the spinning line is suppressed, and the thinning behavior is stabilized. The spinning speed is more preferably 350 to 2500 m / min, further preferably 400 to 2000 m / min, and particularly preferably 450 to 1500 m / min.

  The unstretched yarn having a low molecular orientation of the core component and the sheath component is molecularly oriented in a subsequent stretching step. At this time, the core is stretched in two or more stages and the stretching temperature is increased in stages. This is preferable because the molecular orientation of the component and the sheath component can be increased uniformly.

  And it is very important to heat-set at 160-220 degreeC with the last roll after extending | stretching. By increasing the heat setting temperature to the limit and increasing the mobility of the molecular chain, the molecular chain of the amorphous phase in the aliphatic polyester (A) and the thermoplastic polyamide resin (B), respectively, is crystallized, This is preferable because it can be dipolarized with molecular chains that are randomly arranged by relaxing the orientation. Furthermore, since the above temperature range is in the vicinity of the melting point Tma of the aliphatic polyester, a part of the core component is melted on the final roll, and the distortion of the core-sheath interface stored before the heat setting is released, thereby obtaining As a result, the peel resistance of the crimped yarn to be obtained is dramatically increased. More preferably, it is 170 degreeC or more, More preferably, it is 180 degreeC or more. On the other hand, it is preferable to set the temperature of the final roll to 220 ° C. or lower because the problem that the cross section of the single fiber is deformed by the melting of the sheath component and the core component is exposed on the surface can be avoided. More preferably, it is 210 degrees C or less, More preferably, it is 200 degrees C or less. And after heat setting in the above range with the final roll, the yarn is immediately fed into the nozzle, that is, the yarn temperature in the crimped nozzle is made near the melting point (Tmb) of the thermoplastic polyamide resin (B) by the preheating effect. As a result, a crimped yarn having a two-phase structure of a crystalline phase and a random amorphous phase is obtained for both the core component and the sheath component. This makes it possible for the first time to suppress the occurrence of distortion and residual stress at the core-sheath interface and to significantly improve the peel resistance. In order to increase the yarn temperature in the crimping nozzle, a method of shortening the distance from the final roll to the crimping nozzle, a method of keeping the fiber in a heat insulation box, and a method of heating with a non-contact heater are also preferably used. .

  The “crimp elongation after boiling water treatment” which is an index of the bulky property of the crimped yarn comprising the core-sheath composite fiber of the present invention, or “the elongation under constraint load” is an index of the fastness of crimp. The final roll temperature is also important in controlling the "", and the higher the final roll temperature, the higher the crimp elongation after boiling water treatment and the elongation under constraint load. For the purpose of obtaining a crimped yarn excellent in peel resistance in the present invention, the total draw ratio, the temperature of the draw roll, and the temperature of the final roll after drawing in order to have the required range of strength. It is preferable to adjust the temperature of the crimping nozzle within a preferable range and sufficiently relax the molecular orientation of the amorphous phase in the crimping process. In order to obtain the range where the boil-off of the crimped yarn of the present invention is required, the temperature of the final roll after drawing and the temperature of the crimped nozzle are adjusted within a preferable range, and then after being applied to a cooling drum and taken up. The film is preferably wound at a lower speed than the final roll after stretching.

  For example, when stretching is performed in two stages, the first stage stretching roll is set to 50 to 90 ° C., the second stage stretching roll is set to 90 to 150 ° C., and the final roll after stretching is set to 160 to 220 ° C. for heat setting. It is preferable. More preferably, the first-stage stretching roll is 60 to 80 ° C., the second-stage stretching roll is 100 to 140 ° C., and the final roll after stretching is 170 to 210 ° C.

  When stretching is performed in three stages, the first stage stretching roll is 50 to 90 ° C., the second stage stretching roll is 90 to 130 ° C., the third stage stretching roll is 130 to 160 ° C., and after stretching It is preferable that the final roll of is 160-220 degreeC. More preferably, the first-stage stretching roll is 60 to 80 ° C., the second-stage stretching roll is 100 to 120 ° C., the third-stage stretching roll is 140 to 150 ° C., and the final roll after stretching is 170 ~ 210 ° C.

And by making the total draw ratio 2 to 5 times and increasing the molecular orientation moderately, heat shrinkage can be completed immediately in the crimp nozzle, leaving a history of excessive strain on the core-sheath interface. It is difficult and preferable. In addition, by stretching at an appropriate draw ratio as described above, crystallization of the core component and the sheath component can be promoted, and a crimped yarn that can maintain the peel resistance for a longer period of time is obtained, and the crimp fastness is also improved. It is preferable because it is enhanced. The overall draw ratio is more preferably 2.5 to 4.5 times, and further preferably 2.8 to 4.3 times. The overall draw ratio of the present invention is defined by the speed ratio between the first-stage drawing roll and the final roll after drawing, and can be calculated by the following formula.
Total draw ratio = [speed of final roll after drawing (m / min)] / [speed of first-stage drawing roll (m / min)].

  The drawn yarn that has been heat-set in the final roll after drawing is preferably crimped by a nozzle in an air jet stuffer crimping apparatus. As a crimping apparatus for forming a BCF yarn which is a preferred crimping form in the present invention, a crimping apparatus for performing a normal heated fluid processing process may be used. For example, a jet nozzle type, a jet Various crimping methods such as stuffer type and 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. In order to improve the peel resistance of the crimped yarn, the yarn temperature in the crimp nozzle is increased, and the core component and sheath component of each single fiber are uniformly and immediately heated to a high temperature state. It is preferable to make it shrink, and it is preferable to make the temperature of a crimp nozzle 5-100 degreeC higher than the final roll temperature after extending | stretching.

  In the present invention, when the drawing step and the crimping process are performed in separate steps, it is extremely effective to heat-treat the drawn yarn again with a heat source such as a heat roll or a hot plate before supplying the yarn to the crimping nozzle. It is. By performing the reheat treatment, it becomes easy to increase the yarn temperature in the crimp nozzle, and as described above, the history of the difference between the heat shrinkage characteristics of the core component and the sheath component is difficult to remain at the core-sheath interface, which is preferable. . The temperature of the reheat treatment is preferably 160 to 220 ° C, more preferably 170 to 210 ° C, and particularly preferably 180 to 200 ° C.

  Moreover, after providing crimps, it is preferable because the fiber structure of the crimped yarn can be fixed by pulling it against a cooling drum and the yield can be lowered. The longer the contact length between the cooling drum and the crimped yarn (contact length), the more the fiber structure can be fixed, and the crimped yarn is distorted in the subsequent winding process or higher processing process. However, the fiber structure of the crimped yarn is less likely to change again, and is preferable because boiling yield can be kept low. The contact length is preferably 20 cm or more, more preferably 30 cm or more, and further preferably 40 cm or more.

  It is preferable to take up the sheet after applying it to the cooling drum and then winding the crimped yarn at a lower speed than the final roll so as not to apply excessive strain to the crimped yarn. The temperature of the cooling drum is usually room temperature (25 ° C.). At this time, when the winding speed is 10 to 30% lower than the speed of the final roll, the fiber structure fixed by the cooling drum can be kept low without changing the fiber structure again, and the core can be kept low. Residual stress is unlikely to occur at the sheath interface, which is preferable because the crimped yarn has excellent peel resistance.

  Further, it is preferable to stretch between the cooling drum and the winder with an appropriate tension because the uniformity of crimp can be improved (bias of crimp and unevenness can be suppressed). For example, it is possible to employ a method in which two rolls are arranged between a cooling drum and a winder and tension is applied by a speed difference between the rolls. At this time, if the tension is excessively high, the crimp may sag. Therefore, the stretching tension is preferably 0.02 to 0.2 cN / dtex, and preferably 0.04 to 0.15 cN / dtex. More preferred.

  The entanglement process may be performed at any stage after winding the crimped yarn with a winder or after winding. The number of entanglement treatments and the treatment pressure are preferably adjusted so that the CF value of the crimped yarn is 3 to 30, but the entanglement performed before the drawing step may be unwound by drawing, It is preferable to apply just before. Further, since the yarn immediately before winding is under low tension, it is likely to be entangled with low-pressure air pressure (CF value is likely to be increased). For this reason, since excessive distortion is not added to a crimped yarn and peeling resistance can be improved, it is preferable. The treatment pressure air is preferably 0.05 to 0.5 MPa.

  On the other hand, the crimping process is not limited to the air jet stuffer crimping process, and the crimping process can be performed by false twisting. In this case, a high-relaxation process (buleria process) is performed while heating after untwisting, so that a two-phase structure of a crystalline phase and a non-oriented amorphous phase can be formed, improving the peel resistance. It is preferable because it is easy to do.

  The crimped yarn thus obtained can be used for a fiber structure. Furthermore, the obtained crimped yarn can be processed into a carpet by a conventional method and used as a carpet for an automobile interior.

  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 device: Waters 2690
Column: Two Shodex GPC K-805L (8 mm ID * 300 mm L) are connected and used: Chloroform (Wako, for HPLC)
Temperature: 40 ° C
Flow rate: 1 ml / min Sample concentration: 10 mg / 4 ml
Filtration: Maishori 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 viscosity of thermoplastic polyamide (ηrB)
The sulfuric acid relative viscosity of the thermoplastic polyamide was measured at 25 ° C. by preparing a 98% sulfuric acid solution of 0.01 g / mL.

D. Relative Viscosity of Aliphatic Polyester The relative viscosity of aliphatic polyester was measured at 25 ° C. by preparing a 0.01 g / mL o-chlorophenol solution.

E. Polymer melting point Using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc., obtained by measuring 20 mg of a sample (component A, component B), which is the original polymer of crimped yarn, at a heating rate of 16 ° C./min. In the differential calorimetric curve, the temperature at which the 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 differential calorimetric curve of the fiber belongs to was determined by the following method.

  First, using a crimped yarn (fiber 1: crimped yarn containing component A and component B) as a sample, DSC measurement was performed under the same measurement conditions as described above to obtain a differential calorimetric curve 1. Next, component A in the crimped yarn (fiber 1) is removed with a solvent (chloroform), and the resulting fiber is washed with water and vacuum dried at room temperature for 24 hours (fiber 2: component B). DSC measurement was performed under the same conditions as above to obtain a differential calorimetric curve 2. The melting point peak of the differential calorimetric curve 2 was judged as the melting point peak of component B, and Tmb was determined. Further, the differential calorific curves 1 and 2 were compared, and the disappearing melting peak was determined to be a melting peak of component A, and Tma was determined from the differential calorific curve 1.

F. Sum of heat capacity of melting peak of differential calorimetric curve of crimped yarn 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 E. 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.

G. Melt viscosity (ηA, ηB)
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) in ^-1 was measured. The measurement was performed 3 times and the average value was taken as the melt viscosity.

H. Core-sheath ratio When subjected to melt spinning, the weight of the core component (consisting of component A) and the weight of the sheath component (consisting of component B) are respectively measured, and the sum of the weights of the core component and the sheath component is 100. It was calculated by calculating the weight ratio of each of the core component and the sheath component.

  When the weight ratio between the core component and the sheath component at the time of manufacture is unknown, it can be calculated simply using the following formula. That is, the core component of the crimped yarn of the present invention may contain component A and other minor components, and the sheath component may contain component B and other minor components. It can be considered that the component consists essentially of component A and the sheath component consists only of component B, and the core-sheath ratio can be calculated as the weight ratio of the core component to the sheath component.

First, a cross-sectional slice of the crimped yarn is prepared, the polyamide component of the slice is metal-stained with phosphotungstic acid, and the cross-section of the crimped yarn is observed at a magnification of 4,000 with a transmission electron microscope (TEM). I took a picture. At this time, the unstained area is determined as component A, and the stained area is determined as component B, so that the core-sheath interface is determined, and the image is analyzed by the image analysis software “WinROOF” of Mitani Corporation. By analyzing, the total area (Aa) of the region constituting the core component and the total area (Ab) of the region constituting the sheath component were determined. 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.
Core-sheath ratio = weight ratio of core component / weight ratio of sheath component Weight ratio of core component = [(Aa × 1.26) / (Aa × 1.26 + Ab × 1.14)] × 100
Weight ratio of sheath component = [(Ab × 1.14) / (Aa × 1.26 + Ab × 1.14)] × 100
TEM apparatus: Hitachi H-7100FA type condition: accelerating voltage 100 kV.

I. Minimum value of sheath component thickness Using the image taken in accordance with the method for observing the cross-section of the crimped yarn shown in the section of H, the section with the smallest sheath component thickness in the cross section is used. , Measure the thickness. The portion from which the cross-sectional slice of the crimped yarn was collected was randomly changed, 10 photographed images were collected, the above measurement was performed for each, and the average value was set to the minimum value of the sheath component thickness.

J. et al. 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.

K. Total fineness A 100 m crimped yarn is measured in a skein shape with a measuring scale, the weight of the 100 m crimped yarn is measured, and the total fineness (dtex) is calculated by multiplying the weight by 100. The measurement was performed three times, and the average value was defined as the total fineness (dtex).

L. Single fiber fineness The single fiber fineness (dtex) was calculated by dividing the total fineness by the number of filaments.

M.M. Strength and elongation According to the constant speed elongation conditions shown in JIS L1013 (chemical fiber filament yarn test method, 1998), the strength of the crimped yarn using Tensilon UCT-100 manufactured by Orientec Co., Ltd. And the elongation was measured. At this time, with a sample length of 200 mm and a tensile speed of 200 m / min, the strength is obtained by dividing the strength of the point showing the maximum strength in the SS curve by the total fineness, and the elongation is the maximum strength in the SS curve. It was determined from the elongation of the indicated points.

N. Boiling and crimped yarns are immersed in boiling water for 15 minutes under no load, and the removed crimped yarns after the boiling water treatment are dried at 25 ° C. and a humidity of 65% for 24 hours. The dimensions of the crimped yarn before boiling water treatment and after boiling water treatment were measured, and the boiling yield was obtained by the following formula.
Boiling yield (%) = [(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.

O. 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.

P. Deformation degree of crimped yarn Using the image taken according to the method for observing the cross section of the crimped yarn shown in the section H, the diameter D1 of the circumscribed circle of the cross section of the crimped yarn and the cross section of the single fiber From the diameter D2 of the inscribed circle, the following equation was used.
Deformity = D1 / D2.

Q. Deformation degree of core component Using the image taken in accordance with the method for observing the cross section of the crimped yarn shown in the section H, the diameter D3 of the circumscribed circle of the cross section of the core component and the cross section of the core component It calculated | required by following Formula from the diameter D4 of the inscribed circle.
Deformity = D3 / D4
R. 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.

S. Elongation rate after boiling water treatment under 2 mg / dtex load (Elongation rate under restraint load)
In the term R, when the immersion treatment is carried out with boiling water, in the state where the load of 2 mg / dtex is suspended on the crimped yarn, except that the crimped yarn is treated with boiling water, The elongation rate under restraining load was measured.

T.A. 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 X: 11 or more thread breaks

U. Abrasion resistance evaluation of crimped yarn After twisting the two twisted yarns by applying S-twisted and Z-twisted to the crimped yarn, the wound yarn in the form of a cheese package, containing a gold-containing dye ("Irgaran Red 4GL") [Ciba-Gaigi Co., Ltd.]) 0.6% owf, bath ratio 1:50 (as crimped yarn), pH = 7, treated at 98 ° C. for 60 minutes and dyed. After dyeing, it was washed with water and dried with hot air at 50 ° C. for 24 hours to obtain a dyed twisted yarn. The twisted yarn was tufted into a PP spunbonded nonwoven fabric as a surface yarn, and then a backing material was applied to the back of the base fabric and dried to obtain a tufted carpet (weighing 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 was attached to a Taber abrasion tester (Rotary Abaster) defined in ASTM D 1175 (1994) with the surface facing up, H # 18 abrasion rod, compression load 1 kgf, sample holder rotation speed 70 rpm, number of abrasions 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.

V. Peeling resistance A tubular knitted fabric made of crimped yarn is prepared, and the tubular knitting is made of a metal-containing dye (“Irgaran Red 4GL” [manufactured by Ciba-Gaigi Co., Ltd.)] 0.6% owf, bath ratio 1:50 (cylinder knitting) As the ground), it was dyed by treatment at 98 ° C. for 60 minutes at pH = 7. After dyeing, it was washed with water and dried with hot air at 50 ° C. for 24 hours to obtain a dyed tubular knitted fabric. A 50 × 100 mm strip is cut out from the dyed tubular knitted fabric and used as a sample. A SCOTT TYPE CREASE-FLEX ABRATION TESTER, manufactured by Daiei Kagaku Seisakusho Co., Ltd., Model: CF-10N ), The number of tests was 1000 times, the chuck interval was 0 mm, the friction stroke was 45 mm, and the pressing load was 0.5 kg. evaluated. And about the same circular knitting, the measurement was performed 5 times and comprehensive evaluation was determined by the total score of each evaluation.

<Evaluation criteria>
5 points: no change in appearance 4 points: partial lightening is observed 3 points: lightening is observed and hairballs are partially observed
2 points: Whitening is observed and hairballs are frequently generated.
1 point: Whitening is observed, pills are frequently generated, and the sample is perforated.

<Comprehensive evaluation>
Double circle (excellent): 21 to 25 points ○ (good): 16 to 20 points Δ (possible): 11 to 15 points × (inferior): 5 to 10 points.

W. Flexibility and bulkiness of carpets and tubular knitted fabrics For carpets made in U and tubular knitted fabrics made in V, the touch feeling (flexibility) when pressed with the palm, and the swelling feeling (bulky nature) visually. , Double circle (excellent), ○ (good), Δ (possible), × (inferior) was evaluated in four stages.

[Production Example 1] (Production of polylactic acid (PLA-1))
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 220 minutes in a nitrogen atmosphere To obtain polylactic acid (PLA-1). The obtained polylactic acid (PLA-1) had a weight average molecular weight of 210,000. The amount of lactide remaining was 0.13% by weight. The melting point of the polymer (PLA-1) was 170 ° C., the heat capacity of the melting peak was 45 J / g, the melt viscosity was 200 Pa · sec ⁻¹ , and the relative viscosity was 3.42.

[Production Example 2] (Production of polylactic acid (PLA-2))
Lactide produced from L-lactic acid having an optical purity of 99.5% is polymerized at 180 ° C. for 350 minutes in a nitrogen atmosphere in the presence of a bis (2-ethylhexanoate) tin catalyst (lactide to catalyst molar ratio = 10000: 1). To obtain polylactic acid (PLA-2). The obtained polylactic acid (PLA-2) had a weight average molecular weight of 260,000. The amount of residual lactide was 0.14% by weight. The melting point of the polymer (PLA-2) was 170 ° C., and the melting point peak heat capacity was 45 J / g. The melt viscosity was 300 Pa · sec ⁻¹ . The relative viscosity was 3.76.

[Production Example 3] (Production of polylactic acid (PLA-3))
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 To obtain polylactic acid (PLA-3). The resulting polylactic acid (PLA-3) had a weight average molecular weight of 150,000. The amount of residual lactide was 0.10% by weight. The melting point of the polymer (PLA-3) was 170 ° C., the heat capacity of the melting peak was 48 J / g, the melt viscosity was 120 Pa · sec ⁻¹ , and the relative viscosity was 3.04.

[Production Example 4] (Production of polylactic acid (PLA-4))
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-4). The obtained polylactic acid (PLA-4) had a weight average molecular weight of 210,000. The amount of lactide remaining was 0.12% by weight. The melting point of the polymer (PLA-4) was 130 ° C., the heat capacity of the melting peak was 38 J / g, and the melt viscosity was 200 Pa · sec ⁻¹ . The relative viscosity was 3.42.

[Production Example 5] (Production of polylactic acid (PLA-5) containing 10% by weight of MADGIC) PLA-1 and component C (mono-allyl diglycidyl isocyanuric acid (hereinafter referred to as MADGIC) manufactured by Shikoku Kasei Co., Ltd.) After being dried, it was supplied to a twin-screw kneading extruder so that PLA-1: MADGIC = 90: 10 (weight ratio), kneaded at a cylinder temperature of 200 ° C. and polylactic acid (PLA containing 10% by weight of MADGIC) -5) was obtained. The amount of residual lactide of the obtained polylactic acid (PLA-5) was 0.15% by weight. The melting point of the polymer (PLA-5) was 170 ° C., the heat capacity of the melting peak was 44 J / g, the melt viscosity was 190 Pa · sec ⁻¹ , and the relative viscosity was 3.38.

[Production Example 6] (Production of polylactic acid (PLA-6) containing 10% by weight of polycarbodiimide)
After PLA-1 and component C (Nisshinbo Co., Ltd. polycarbodiimide “LA-1”) were dried, PLA-1: LA-1 = 90: 10 (weight ratio) was added to a twin-screw kneading extruder. The resulting mixture was kneaded at a cylinder temperature of 200 ° C. to obtain polylactic acid (PLA-6) containing 10% by weight of LA-1. The amount of residual lactide of the obtained polylactic acid (PLA-6) was 0.15% by weight. The melting point of the polymer (PLA-6) was 170 ° C., the heat capacity of the melting peak was 44 J / g, the melt viscosity was 190 Pa · sec ⁻¹ , and the relative viscosity was 3.38.

[Production Example 7] (Production of polylactic acid (PLA-7) containing 10% by weight of a compound having ethylene-glycidyl acrylate as the main chain and grafted with polymethyl methacrylate)
After drying PLA-1 and component C (“Modiper A4200” (hereinafter abbreviated as “Modiper”) manufactured by NOF Corporation, PLA-1: “Modiper” = 80: 20 (weight ratio). Was supplied to a biaxial kneading extruder and kneaded at a cylinder temperature of 200 ° C. to obtain polylactic acid (PLA-7) containing 20% by weight of “Modiper”. The amount of residual lactide of the obtained polylactic acid (PLA-7) was 0.15% by weight. The melting point of the polymer (PLA-7) was 170 ° C., the heat capacity of the melting peak was 44 J / g, the melt viscosity was 190 Pa · sec ⁻¹ , and the relative viscosity was 3.38.

(Example 1)
Using a spinning drawing continuous crimping device equipped with a uniaxial kneader for each of the core component and the sheath component shown in FIG. 3, melt spinning, drawing, heat treatment, and crimping treatment were continuously performed to obtain a BCF yarn. .

The core component hopper 1 shown in FIG. 3 is charged with component A (PLA-1), and the sheath component hopper 2 is charged with component B (N6-1 melting point 225 ° C., melting point peak heat capacity 79 J / g, relative viscosity 2. 59, melt viscosity 150 Pa · sec ⁻¹ ), and component A and component B are separately melted and kneaded by the single-screw extrusion kneaders 3 and 4 respectively and led to the spinning block 5, and the gear pumps 6 and 7 are fed. Each polymer was weighed and discharged, led to a built-in spin pack 8, and spun from a spinneret 9 having 96 holes for a trilobal cross section. At this time, the rotational speeds of the gear pumps 6 and 7 of the core component and the sheath component were selected so that the core-sheath ratio = 40/60 (weight ratio). 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, the speed of the 2nd roll 14 is made into the speed of 1.02 times of the speed of the 1st roll 13, and after adding stretch to undrawn yarn, the 2nd roll 14 and the 3rd roll 15 The third roll 15 is heat treated, the third roll 15 and the fourth roll 16 are stretched again, the fourth roll 16 is heat treated again, and the fourth roll 16 is heated. Air stuffer crimping is applied by a crimping nozzle 17 using a heated fluid while relaxing (overfeeding) the yarn between the fifth roll (cooling drum) 18 and the fifth roll (cooling drum) 18. The crimped yarn is cooled to fix the structure on the surface, and tension (0.08 cN / dtex, the fineness is the fineness of the wound crimped yarn) so as not to stretch the crimp between the sixth roll 19 and the seventh roll 20. Using ), And tension is applied between the seventh roll 20 and the winder 22 (0.08 cN / dtex, the fineness is the fineness of the wound crimped yarn). As a result, a 1920 dtex 96-filament BCF yarn (cheese package 21) obtained by performing spinning, drawing, heat treatment, and crimping treatment in one stage was obtained. Although about 100 kg was sampled, yarn breakage, single fiber flow, etc. did not occur, and the yarn production was extremely stable. The results of Example 1 are shown in Table 1. The melt spinning, drawing, heat treatment, and crimping treatment conditions are as follows.
-Kneader temperature: 230 ° C
-Spinning temperature: 245 ° C
Filter layer: 30 # Morundum sand filling Filter: 20 μm nonwoven filter Filter base 1 (base just before polymer discharge): slit width 0.15 mm, slit length 1.5 mm, number of holes 96
A base 2 (a base in the schematic diagram 29 of FIG. 6, which is provided immediately before the base 1 and has separate flow paths for the core component and the sheath component):
Sheath component hole diameter 0.5mm, discharge hole length 0.5mm, 3 holes per filament
Core component Slit width 0.12mm, Slit length 1.2mm, 1 hole per filament
・ Discharge rate: 498.6 g / min (1 pack, 1 thread, 96 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: 70 ° C
-Third roll temperature: 135 ° C
-Fourth roll temperature: 190 ° C
-5th roll temperature: 25 degreeC
-Sixth roll temperature: 25 ° C
-Seventh roll temperature: 25 ° C
・ Heat treatment temperature: 230 ℃
First roll speed: 840 m / min (= second roll speed / 1.02)
-Second roll speed: 857 m / min-Third roll speed: 2400 m / min-Fourth roll speed: 3000 m / min-Fifth roll speed: 80 m / min-Sixth roll speed: 2550 m / min-Seventh roll speed : 2600 m / min. Winding speed: 2550 m / min. Total draw ratio: 3.5 times (second to third rolls: 2.8 times, third to fourth rolls: 1.25 times). The obtained BCF yarn had a crimped form in which the single fibers were bent in a loop shape in an irregular direction to form a slack, and the single fibers were intertwined. The strength was 2.3 cN / dtex, the boiling yield was 2.2%, and the single fiber fineness was 20 dtex. Moreover, it was a crimped yarn having a crimped elongation rate of 25% and an elongation rate of 13% under a restrained load, showing excellent crimp characteristics and having a crimp that is difficult to set. When the tubular knitted fabric and the carpet were produced using the crimped yarn, both had a voluminous feel, a soft touch, an aesthetic gloss, and an excellent texture.

  As a result of the peel resistance evaluation using the obtained tubular knitted fabric made of crimped yarn, there was no change in the appearance, and excellent peel resistance was exhibited. Moreover, as a result of carrying out the abrasion resistance test of the carpet using the obtained crimped yarn, the wear weight loss rate is 10% and has an excellent abrasion resistance. Whitening and sheath cracking were not observed.

  As a result of TEM observation of the cross section of the single fiber of the obtained crimped yarn, the core component is located at the center of the single fiber, the minimum thickness of the sheath component is 3.0 μm, and the core component is all sheath It was coated with ingredients. And the irregularity degree of the single fiber was 3.0, and the irregularity degree of the core component was 3.0. Further, the melting points of the crimped yarns by DSC were 169 ° C. (peaks derived from component A) and 224 ° C. (peaks derived from component B), and melting peaks attributable to the respective components were observed. The total of was 72 J / g, indicating sufficient crystallinity.

(Comparative Example 1)
In Example 1, except that the component B was not used and the base was changed, an attempt was made to obtain a BCF yarn consisting only of the component A under the same conditions as in Example 1, but the fourth roll 16 and the crimped nozzle 17 In this case, the single fiber was severely fused and could not be produced. Therefore, the third roll 15 temperature, the fourth roll 16 temperature, and the crimp nozzle 17 temperature were changed to obtain a crimped yarn of Comparative Example 1 (at this time, the sixth roll 19 speed, the seventh roll 20 speed, the winding) The speed was changed so as to be within the tension range shown in Example 1. Further, the discharge amount was adjusted so that the single yarn fineness was 20 dtex). The yarn-making property was poor, and 15 yarn breaks occurred at 100 kg sampling. The results of Comparative Example 1 are shown in Table 1, and the base specifications, third roll 15 temperature, fourth roll 16 temperature, crimped nozzle 17 temperature, and winding speed of Comparative Example 1 are shown below.
-Base 2 of Comparative Example 1: Core component Slit width 0.12 mm, slit length 1.2 mm, 1 filament with 1 hole (no sheath component channel)
-Third roll 15 temperature of Comparative Example 1: 90 ° C
-4th roll 16 temperature of the comparative example 1: 110 degreeC
-Crimp nozzle 17 temperature of Comparative Example 1: 150 ° C
-Winding speed of Comparative Example 1: 2670 m / min.

From Example 1 and Comparative Example 1, it can be seen that the crimped yarn of the present invention has a sheath component and thus becomes a crimped yarn excellent in wear resistance and crimp characteristics. Since Comparative Example 1 did not have a sheath component in the peel resistance test, the peeling phenomenon at the core-sheath interface was not observed, but the crimped yarn was scraped and fibrillated, and the holes were also observed. It was done. Further, the crimped yarn of Comparative Example 1 was found to have fused portions, and the strength was as low as 1.2 cN / dtex, and many yarn breaks occurred in the process of producing the tubular knitted fabric and carpet. In addition, molecular chains with a high degree of orientation remain in the crimped yarn and the boiling yield is as high as 10%. Therefore, the peel resistance, wear resistance, and crimp characteristics of the crimped yarn deteriorate over time. there were.

(Examples 2-3, Comparative Examples 2-3)
In Example 1, except that the temperature of the fourth roll 16 was changed, crimped yarns of Examples 2-3 and Comparative Examples 2-3 were obtained in the same manner as in Example 1 (at this time, the speed of the sixth roll 19) The seventh roll 20 speed and the winding speed were adjusted to be the tension shown in Example 1). In Examples 2 and 3, thread breakage occurred once each, although not at a problematic level. The yarn forming properties of Comparative Examples 2 and 3 were poor, and the breakage of each yarn was 12 times in Comparative Example 2 and 13 times in Comparative Example 3. The results of Examples 2-3 and Comparative Examples 2-3 are shown in Table 1. The spinning conditions of Examples 2-3 and Comparative Examples 2-3 are described below.
Fourth roll 16 temperature Example 2: 170 ° C.
Example 3: 220 ° C
Comparative Example 2: 130 ° C
Comparative Example 3: 225 ° C.
As can be seen by comparing Examples 1 to 3 and Comparative Examples 2 to 3, by adopting a heat treatment temperature of 160 to 220 ° C. of the final roll after stretching, it has strength and boiling yield that are preferred in the present invention. A crimped yarn having excellent peel resistance can be obtained with high productivity. This is because, by adopting the above preferable manufacturing conditions, the fiber immediately becomes a high temperature state in the crimp nozzle, so that the core component and the sheath component are not affected by the difference in heat shrinkage characteristics between the core component and the sheath component. It is thought that the molecular orientation of the sheath component is sufficiently low and the crimped yarn contains more crystal phase.

  As can be seen from a comparison of Examples 1 to 3, a crimped yarn having excellent crimp characteristics was obtained by employing a production method that is more preferable in the present invention. For this reason, the tubular knitted fabric and carpet made of the crimped yarn of Example 1 exhibited an excellent texture as compared with Examples 2-3.

(Examples 4-5, Comparative Examples 4-5)
In Example 1, except that the overall draw ratio was changed, crimped yarns of Examples 4 to 5 and Comparative Examples 4 to 5 were obtained in the same manner as Example 1 (the first to third roll speeds were as follows). The first roll 13 speed was set to a value obtained by dividing the second roll 14 speed by 1.02). In Examples 4 to 5, the thread breakage occurred once, although not at a problematic level. The yarn forming properties of Comparative Examples 4 to 5 were poor. In Comparative Example 4, yarn breakage was observed 12 times, and in Comparative Example 5, yarn breakage was observed 14 times. Table 2 shows the results of Examples 4 to 5 and Comparative Examples 4 to 5. The spinning conditions of Examples 4 to 5 and Comparative 4 to 5 are described below.
-Overall draw ratio Example 4: 2.1 times (second to third rolls: 1.68 times, third to fourth rolls: 1.25 times)
Example 5: 4.6 times (second to third rolls: 3.68 times, third to fourth rolls: 1.25 times)
Comparative Example 4: 1.9 times (second to third roll: 1.52 times, third to fourth roll: 1.25 times)
Comparative Example 5: 5.1 times (second to third rolls: 4.08 times, third to fourth rolls: 1.25 times)
. As can be seen by comparing Examples 1, 4 to 5 and Comparative Examples 4 to 5, by adopting the overall draw ratio which is preferable in the present invention, it has strength and boiling yield which are preferable in the present invention. It turns out that it becomes a crimped yarn and becomes a crimped yarn excellent in peeling resistance. Since the core component and the sheath component of the drawn yarn are uniformly oriented by drawing at the above-mentioned overall draw ratio, a difference in heat shrinkage characteristics between the core component and the sheath component hardly occurs in the crimping process. This is probably because the molecular chain adjacent to the interface is not subjected to excessive strain. And since Example 1 had more preferable intensity | strength and boiling yield compared with Examples 4-5, it was a crimped yarn excellent in peeling resistance.

(Examples 6-8, Comparative Examples 6-7)
In Example 1, except that the number of holes of the base 1 was changed, crimped yarns of Examples 6 to 8 and Comparative Examples 6 to 7 were obtained in the same manner as Example 1. Although not at a problematic level, in all of Examples 6 to 8, thread breakage occurred once. In Comparative Examples 6 to 7, the yarn-making property was poor. In Comparative Example 6, thread breakage occurred 12 times, and in Comparative Example 7, thread breakage occurred 11 times. Table 3 shows the results of Examples 6 to 8 and Comparative Examples 6 to 7. The spinning conditions of Examples 6-8 and Comparatives 6-7 are described below.
-Number of base holes Example 6: 320
Example 7: 72
Example 8: 48
Comparative Example 6: 480
Comparative Example 7:40.

As can be seen by comparing Examples 1 and 6 to 8 and Comparative Examples 6 to 7, by using a crimped yarn having a single fiber fineness that is preferable in the present invention, I understand that This is because, by setting the single fiber fineness that is preferable in the present invention, it is possible to obtain a drawn yarn in which the core component and the sheath component are uniformly oriented in the melt spinning process. This is thought to be because unreasonable distortion does not occur in the molecular chain adjacent to.
Further, compared to the tubular knitted fabrics and carpets made of crimped yarns of Examples 6 to 8 and the carpet, the tubular knitted fabrics and carpets made of Example 1 are excellent in volume feeling and the volume feeling is maintained for a long time. It was a thing. That is, by using a crimped yarn having a more preferable single fiber fineness in the present invention, a crimped yarn having high crimp fastness was obtained.

(Examples 9 to 12)
In Example 1, crimped yarns of Examples 9 to 12 were obtained in the same manner as Example 1 except that the resins used as Component A and Component B were changed. In Examples 9 and 10, yarn breakage was not confirmed. In Examples 11 and 12, although not at a problematic level, one thread breakage occurred. The results of Examples 9-12 are shown in Table 4. The resins used in Examples 9-12 are described below.
Resin used for core component and sheath component Example 9: Component A = PLA-1, Component B = N6-2 (melting point 225 ° C., melting point peak heat capacity 77 J / g, relative viscosity 2.95, melt viscosity 300 Pa sec ^-1 )
Example 10: Component A = PLA-1, Component B = N6-3 (melting point 225 ° C., melting point peak heat capacity 78 J / g, relative viscosity 2.10, melt viscosity 50 Pa · sec ⁻¹ )
Example 11: Component A = PLA-2, Component B = N6-3
Example 12: Component A = PLA-3, Component B = N6-2.

  As can be seen by comparing Examples 1 and 9 to 12, by setting the melt viscosity ratio of Component A and Component B used in the present invention to be preferable in the present invention, a crimped yarn excellent in peeling resistance and I understand that By making the melt viscosity ratio preferred in the present invention, it becomes possible to make the stress applied to the core component and the sheath component uniform in the melt spinning process, and the molecules of the core component and the sheath component of the undrawn yarn Since there is almost no difference in orientation, the core component and the sheath component can be uniformly oriented in the stretching process, the difference in heat shrinkage characteristics of each component is reduced, and the molecular chain adjacent to the core-sheath interface is reduced in crimping. It is thought that it becomes difficult to receive excessive distortion. Moreover, compared with the tubular knitted fabrics and carpets made of crimped yarns of Examples 9 to 12 and the carpet, the tubular knitted fabrics and carpets made of Example 1 are excellent in peel resistance, so that sheath cracking occurs and the core component is It can be seen that it is not exposed and has excellent wear resistance.

(Examples 13 to 17)
In Example 1, crimped yarns of Examples 13 to 17 were obtained in the same manner as Example 1 except that the core-sheath ratio (weight ratio) was changed. The result of Examples 13-17 is shown in Table 5, and the core-sheath ratio in each is shown below.
Example 13: Core component / sheath component = 20/80
Example 14: core component / sheath component = 30/70
Example 15: core component / sheath component = 60/40
Example 16: core component / sheath component = 70/30 Example 17: core component / sheath component = 80/20.

  As can be seen from Examples 1 and 13 to 17, a crimped yarn having more excellent peel resistance can be obtained by adopting a core-sheath ratio that is preferable in the present invention. And since the peeling at the core-sheath interface can be suppressed, the core component is not exposed and worn away during wear, and the crimped yarn has more excellent wear resistance. Furthermore, the crimped yarn of Example 1 has higher resistance to peeling and fastness than Examples 13 to 17, and the bulkiness and flexibility are maintained for a long time. .

(Examples 18 to 22)
In Example 1, BCF yarns of Examples 18 to 22 were obtained in the same manner as in Example 1 except that the die was changed to change the irregularity of the single fiber and the irregularity of the core component. The results of Examples 18 to 22 are shown in Table 6, and the base specifications in each are shown below.
-Base of Example 18: slit width 0.3 mm, slit length 1.5 mm, number of holes 96
-Base 18 of Example 18:
Sheath component hole diameter 0.5mm, discharge hole length 0.5mm, 3 holes per filament
Core component Slit width 0.12mm, slit length 0.6mm, 1 hole per filament
Base 19 of Example 1: Slit width 0.15 mm, slit length 2.25 mm, number of holes 96
-Base 2 of Example 19:
Sheath component hole diameter 0.5mm, discharge hole length 0.5mm, 3 holes per filament
Core component Slit width 0.12mm, slit length 1.8mm, 1 hole per filament
Base 20 of Example 1: Slit width 0.25 mm, slit length 0.75 mm, number of holes 96
-Base 20 of Example 20:
Sheath component hole diameter 0.5mm, discharge hole length 0.5mm, 3 holes per filament
Core component Slit width 0.12mm, slit length 0.48mm, 1 hole per filament
Base 21 of Example 21: Slit width 0.15 mm, slit length 2.70 mm, number of holes 96
-Base 2 of Example 21:
Sheath component hole diameter 0.5mm, discharge hole length 0.5mm, 3 holes per filament
Core component Slit width 0.12 mm, slit length 2.16 mm, 1 hole per filament.
Base of Example 22: Base hole diameter 0.6 mm, discharge hole length 0.6 mm, number of holes 96
-Base 2 of Example 22:
Sheath component hole diameter 0.5mm, discharge hole length 0.5mm, 3 holes per filament
Core component Hole diameter 0.6 mm, discharge hole length 0.6 mm, 1 hole per filament. As can be seen from Examples 1 and 18 to 22, a crimped yarn excellent in peel resistance and abrasion resistance was obtained by setting the degree of irregularity of the single fiber in a preferred range in the present invention.

(Examples 23 to 25)
In Example 17, BCF yarns of Examples 23 to 25 were obtained in the same manner as in Example 17 except that the tip supplied to the core component hopper was changed. The results of Examples 23 to 25 are shown in Table 7, and the chips supplied to the core component hopper in each are shown below.
Chip of core component of Example 23: PLA-1 / PLA-5 = 90/10 (weight ratio) Chip blend Chip of core component of Example 24: PLA-1 / PLA-6 = 90/10 (weight) Ratio) Chip Blend: Chip of core component of Example 25: PLA-1 / PLA-7 = 90/10 (weight ratio) chip blend.

As can be seen from Examples 17 and 23 to 25, the crimped yarn contains component C (compatibilizer), so that the adhesion at the core-sheath interface is increased, and the crimp is excellent in peeling resistance and abrasion resistance. It turns out that it becomes a thread.

(Examples 26 to 30)
In Example 1, BCF yarns of Examples 26 to 30 were obtained in the same manner as in Example 1 except that the chips used as Component A and Component B were changed. In Example 29, since spinning could not be performed at the same spinning temperature as in Example 1, the spinning temperature was 270. The result of Examples 26-30 is shown in Table 8, and the component A and the component B in each are shown below.
Example 26: Component A / Component B = PLA-1 / N11
Example 27: Component A / Component B = PLA-1 / (N6 / N66)
Example 28: Component A / Component B = PLA-1 / N610
Example 29: Component A / Component B = PLA-1 / N66
Example 30: Component A / Component B = PLA-4 / N6-1.
N11: nylon 11, melt viscosity 150 Pa · sec ⁻¹ , melting point 185 ° C., melting peak heat capacity 42 J / g
N6 / N66: nylon obtained by copolymerization of nylon 6 and nylon 66 monomers at a molar ratio of 80/20, relative viscosity of 2.59, melting point of 200 ° C., melting peak heat of 50 J / g, melt viscosity of 150 Pa · sec ⁻¹
N610: Nylon 610, relative viscosity 2.59, melting point 225 ° C., peak of heat of fusion 68 J / g, melt viscosity 150 Pa · sec ⁻¹
N66: nylon 66, relative viscosity of 2.59, melting point of 260 ° C., peak of heat of fusion 73 J / g, melt viscosity of 150 Pa · sec ⁻¹
As can be seen from Example 1 and Examples 26 to 28, it is understood that a crimped yarn having more excellent peel resistance can be obtained by using component B having high crystallinity as a sheath component in the present invention. Further, the higher the crystallinity of the crimped yarn, the higher the fastness of the crimp, and the bulkiness and flexibility of the tubular knitted fabric and carpet were maintained, and the texture was excellent.

  As can be seen from Example 1 and Examples 29 to 30, by using Component A and Component B having melting points in a preferred range in the present invention, Component A is thermally deteriorated and the viscosity is decreased. It can be seen that the occurrence of viscosity spots inside can be suppressed, and the crimped yarn has excellent peel resistance. Since there is no viscosity unevenness in the component A, the core component and the sheath component are easily orientated uniformly in the spinning / stretching process. Since it becomes a crimped yarn with low boiling yield, it becomes a crimped yarn excellent in peel resistance.

  Moreover, since Example 1 has arrange | positioned the core component in the center part in the cross section of a fiber compared with Examples 29-30, and has coat | covered the core component uniformly with a sheath component, it is abrasion-resistant. Was also excellent.

(Example 31)
A BCF yarn of Example 31 was obtained in the same manner as in Example 1 except that the spinning temperature was 270 ° C. in Example 1. The spinnability was not very good, and 10 yarn breakage occurred with 100 kg spinning.

  As can be seen from a comparison between Example 1 and Example 31, it can be seen that by adopting a spinning temperature that is preferable in the present invention, thermal deterioration of Component A can be suppressed, and the spinning performance can be improved. Further, as the viscosity unevenness due to the thermal deterioration of component A is suppressed, the core component and the sheath component are more easily oriented uniformly in the spinning / drawing process, and the difference in thermal shrinkage between the core component and the sheath component is less likely to occur during crimping. As a result, a crimped yarn having a low boiling point is obtained, so that the crimped yarn has excellent peel resistance.

  Furthermore, by suppressing the thermal deterioration of component A, the core component can be arranged in the center in the cross section of the fiber, and the fiber surface can be uniformly coated with the sheath component (minimum thickness of the sheath component) A large value) and a crimped yarn having excellent wear resistance.

(Example 32)
In Example 17, as shown in FIG. 8, the same as in Example 17 except that a continuous spinning heat treatment apparatus, that is, an apparatus for winding without performing air stuffer crimping after heat treatment was used. A stretched yarn was obtained. The drawn yarn production conditions are shown below.

Drawing yarn production conditions / kneading machine temperature: 230 ° C.
-Spinning temperature: 245 ° C
Filter layer: 30 # Morundum sand filling Filter: 20 μm nonwoven filter Filter base 1 (base just before polymer discharge): slit width 0.15 mm, slit length 1.5 mm, number of holes 96
A base 2 (a base in the schematic diagram 29 of FIG. 6, which is provided immediately before the base 1 and has separate flow paths for the core component and the sheath component):
Sheath component hole diameter 0.5mm, discharge hole length 0.5mm, 3 holes per filament
Core component Slit width 0.12mm, Slit length 1.2mm, 1 hole per filament
・ Discharge rate: 498.6 g / min (1 pack, 1 thread, 96 filaments)
Core-sheath ratio: core component / sheath component = 80/20
・ 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: 10% fatty acid ester emulsion oil agent adheres to the yarn 10% ・ First roll 13 temperature: 25 ° C.
-Second roll 14 temperature: 70 ° C
・ Third roll 15 temperature: 135 ° C.
-Fourth roll 16 temperature: 190 ° C
-7th roll 20 temperature: 25 degreeC
First roll 13 speed: 840 m / min (= second roll speed / 1.02)
-Second roll 14 speed: 857 m / min-Third roll 15 speed: 2400 m / min-Fourth roll 16 speed: 3000 m / min-Seventh roll 20 speed: 2900 m / min-Winding speed: 2860 m / min-Overall Stretch ratio: 3.5 times (second to third rolls: 2.8 times, third to fourth rolls: 1.25 times).

About the obtained drawn yarn, false twisting (buleria processing) was performed using the false twisting apparatus shown in FIG. That is, the drawn yarn 33 unwound from the drawn yarn cheese 31 is taken up by the supply roll 36 through the yarn path guides 32, 34, 35, and then heated by the first heater 37 to heat-set the twist, and the yarn path guide 38 is Then, it is cooled by the cooling plate 39. Thereafter, the film is untwisted by a triaxial twister 40 and taken up by a drawing roll 41. Subsequently, it heats with the 2nd heater 42, and winds the false twisted yarn 46 through the delivery roll 43 and the yarn path guides 44 and 45, respectively. At this time, the draw ratio is 1.05 times (= the speed of the draw roll 41 / the speed of the supply roll 36), the temperature of the first heater 37 is 200 ° C., the temperature of the second heater 42 is 120 ° C., and the triaxial twister 40 (urethane) D / Y ratio (= peripheral speed of urethane disk / speed of drawing roll 41) of 1.7, overfeed rate ([{speed of drawing roll 41−speed of delivery roll 43} / speed of drawing roll 41) ] × 100) was 15%, the speed of the delivery roll 43 was 600 m / min, and the drawing false twisting was performed. Yarn breakage and processability were not good, and thread breakage occurred 5 times when obtaining 100 kg false twisted yarn. The false twisted yarn obtained had a crimp elongation of 20% after boiling water treatment, a strength of 2.4 cN / dtex, a single fiber fineness of 20 dtex, a boiling yield of 6%, and an elongation of 45%. In the peel resistance evaluation of the false twisted yarn of Example 32, whitening and pilling are likely to occur, and the appearance may change such as puncture of the sample is observed, and the use is limited in terms of peel resistance. (The overall evaluation of peel resistance was Δ (possible) 11 overall evaluation). The false twisted yarn of Example 29 had a crimped form in which the single fiber had a loop-like bend, but the crimped yarn of Example 17 had a single loop with more irregular loop directionality and amplitude. It was a crimped yarn composed of fibers. That is, by using a BCF yarn having a crimped form that is preferable in the present invention, it is possible to disperse the external force applied to the crimped yarn, and the crimped yarn has excellent peeling resistance. (Comparative Example 8)
In Example 32, the obtained drawn yarn was false twisted in the same manner as in Example 32, except that false twisting (Wooling) was performed under the conditions shown below using the false twisting device shown in FIG. I got a thread. That is, the drawn yarn 33 unwound from the drawn yarn cheese 31 is taken up by the supply roll 36 through the yarn path guides 32, 34, 35, and then heated by the first heater 37 to heat-set the twist, and the yarn path guide 38 is Then, it is cooled by the cooling plate 39. Thereafter, the film is untwisted by a triaxial twister 40 and taken up by a drawing roll 41. Next, the false twisted yarn 46 is wound through the delivery roll 43 and the yarn path guides 44 and 45, respectively. At this time, the draw ratio is 1.05 times (= speed of the draw roll 41 / speed of the supply roll 36), the temperature of the first heater 37 is 200 ° C., and the D / Y ratio of the triaxial twister 40 (urethane disc) (= urethane) Stretch false twisting was performed by setting the peripheral speed of the disk / speed of the stretching roll 41 to 1.7, the speed of the stretching roll 41, and the speed of the delivery roll 43 to 600 m / min. At this time, the threading property and process passability were not good, and yarn breakage occurred five times when a 100 kg false twisted yarn was obtained. The obtained false twisted yarn is a crimped yarn having a good bulkiness and a crimp elongation of 25% after boiling water treatment, a strength of 3.7 cN / dtex, an elongation of 28%, and a boiling yield of 13%. It was. In the peel resistance evaluation of the false twisted yarn of Comparative Example 8, the appearance change is remarkable such that whitening and pilling are likely to occur, the perforation of the sample is observed, and the fiber having poor practicality in terms of peel resistance (The overall evaluation of peel resistance was x (impossible) 6 overall evaluation). As can be seen from a comparison between Example 32 and Comparative Example 8, by performing processing (buleria processing) for performing high relaxation treatment while heating after untwisting, the degree of orientation of the amorphous part is lowered and the temporary yield is low. It turns out that peeling resistance improves by setting it as a twist processing thread | yarn.

It is the photograph of the shape of the fiber which put one mode of BCF yarn of the present invention on the black paper in the state of multifilament, and observed from the upper surface. It is the photograph of the shape of the fiber observed from the upper surface which disperse | distributed the one aspect | mode of the BCF yarn of this invention to a single fiber, put it on the black paper. It is the schematic which shows the one aspect | mode of the spinning | stretch drawing continuous crimp provision apparatus used in Example 1 of this invention. It is a schematic diagram which shows the cross-sectional shape of a crimped yarn. It is a nozzle | cap | die lower surface part side surface plane cross-section schematic diagram explaining a discharge hole length, a hole diameter, a slit length, and a slit width. It is a side cross-sectional schematic diagram which shows the one aspect | mode of the nozzle | cap | die used by the method of this invention. It is a figure explaining the relationship between melt viscosity and relative viscosity. It is the schematic which shows the one aspect | mode of the spin-drawing continuous heat processing apparatus used in Example 33 and Comparative Example 8 of this invention. It is the schematic which shows the one aspect | mode of the apparatus which performs false twist processing to the drawn yarn used in Example 33 of this invention. It is the schematic which shows the one aspect | mode of the apparatus which performs false twist processing to the drawn yarn used in the comparative example 8 of this invention.

Explanation of symbols

1: core component hopper 2: sheath component hopper 3: core component single screw extrusion kneader 4: sheath component single screw 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: Crimp nozzle
18: 5th roll 19: 6th roll 20: 7th roll 21: cheese package 22: winder 23: core component 24: sheath component 25: discharge hole length 26: hole diameter 27: slit length 28: slit width 29: Base 1 (Base just before discharge)
30: Base 2 (having a separate flow path for the core component and the sheath component immediately before the base 1)
31: Stretched yarn cheese 32: Yarn path guide 33: Yarn 34: Yarn path guide 35: Yarn path guide 36: Supply roll 37: First heater 38: Yarn path guide 39: Cooling plate 40: Triaxial twister 41: Stretching Roll 42: Second heater 43: Delivery roll 44: Yarn path guide 45: Yarn path guide 46: False twisted yarn

Claims (13)

A crimped yarn composed of a core-sheath type composite fiber in which the core component is made of an aliphatic polyester resin (A) and the sheath component is made of a thermoplastic polyamide resin (B), and the following (1) to (3) A crimped yarn having the following physical properties:
(1) Strength: 1.5 to 3.0 cN / dtex
(2) Single fiber fineness: 5 to 40 dtex
(3) Boiling yield: 6% or less   The crimped yarn according to claim 1, wherein the crimped yarn is a BCF yarn.   The melt viscosity ratio (ηB / ηA), which is the ratio of the melt viscosity (ηA) of the aliphatic polyester resin (A) and the melt viscosity (ηB) of the thermoplastic polyamide resin (B), is 0.2-2. The crimped yarn according to 1 or 2.   The crimped yarn according to any one of claims 1 to 3, wherein the core-sheath composite fiber has a core-sheath ratio (weight ratio) of 10/90 to 65/35.   The crimped yarn according to any one of claims 1 to 4, wherein the degree of deformation (D3 / D4) of the single fiber of the crimped yarn is 1.3 to 4.   The crimped yarn according to any one of claims 1 to 5, wherein the crimped elongation of the crimped yarn after boiling water treatment is 5 to 35%.   The crimped yarn according to any one of claims 1 to 6, wherein a crimped elongation rate (elongation rate under constraint load) measured after the crimped yarn is treated with boiling water under a load of 2 mg / dtex is 2 to 30%.   The crimped yarn according to any one of claims 1 to 7, wherein the total heat capacity of the melting peak of the differential calorimetric curve obtained by measuring the crimped yarn at a heating rate of 16 ° C / min is 50 J / g or more.   The crimped yarn according to any one of claims 1 to 8, wherein the crimped yarn further comprises a compound (C) containing two or more active hydrogen reactive groups in one molecule as a compatibilizing agent.   A fiber structure in which the crimped yarn according to any one of claims 1 to 9 is used at least in part.   The fiber structure according to claim 10, wherein the fiber structure is a carpet for automobile interior.   Using a direct spinning / drawing / crimping device, spun yarn is produced by joining the aliphatic polyester resin (A) as a core component and the thermoplastic polyamide resin (B) as a sheath component at the nozzle discharge hole and discharging it. The drawn yarn is stretched at a total draw ratio of 2 to 5 times, heat-set at a final roll temperature of 160 to 220 ° C. after being stretched, and then crimped by an air stuffer crimping apparatus. A method for producing a crimped yarn, characterized by performing processing.   Using a direct spinning / drawing / crimping apparatus, the aliphatic polyester resin (A) as the core component, the thermoplastic polyamide resin (B) as the sheath component, and the core-sheath ratio (weight ratio) 65/35 to 10/90 The melt viscosity ratio (ηB / ηA) is in the range of 0.2 to 2 when being merged at the die discharge hole, and the spinning temperature is Tmb relative to the melting point Tmb of the thermoplastic polyamide resin (B). -Tmb + 30 ° C, a spun yarn is formed at a discharge linear velocity of 1 to 20 m / min at the spout discharge hole, and 0.01 to 0.15 m vertically below the spun yarn is set as a cooling start point from the spout surface, After stretching a multifilament cooled with a gas having a wind speed of 0.3 to 1 m / second and a wind temperature of 15 to 25 ° C. from a direction perpendicular to the vertical direction of the base surface, the stretch ratio is 2 to 5 times in two stages, When crimping, the first stage When the temperature is set to 50 to 90 ° C., the second stage drawing roll is set to 90 to 150 ° C., the final roll temperature after drawing is set to 160 to 220 ° C., and is supplied to the air jet stuffer crimping apparatus. The crimping process is performed with the nozzle temperature of the apparatus being 5 to 100 ° C. higher than the final roll temperature after stretching to form a crimped yarn, and it is applied to a cooling drum and is taken up by 10 from the final roll after stretching. The method for producing a crimped yarn according to claim 12, wherein the yarn is wound at a speed of -30% lower.

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