JP4569282B2 - Modified cross-section fiber with excellent lightness - Google Patents

Description

  The present invention relates to a modified cross-section fiber excellent in lightness. More specifically, it is a blend-type irregularly-shaped fiber composed of a specific polymer composition, and has an inclined structure in which the diameter of the void changes from the fiber surface layer part to the fiber center part inside the fiber. Since light reflection by the surface of the cross-sectional fiber and light reflection by the air gap inside the fiber interfere with each other moderately, there is a high-class feeling that is very close to natural silk, which could not be obtained with conventional deformed cross-section fibers The present invention relates to a modified cross-section fiber that is glossy and excellent in lightness.

  In addition, since there are a large number of voids that exist in an inclined manner and the hole structure is not continuous in the fiber axis direction, the voids have excellent durability against external forces, and the voids serve as a cushion. The fiber cross-sectional shape and the inclined structure of the gap are not easily changed by bending or abrasion, and the glossiness is not impaired even in actual use, and it is bulky by having a lot of fine gaps with excellent lightness. It is suitable for formal clothing such as suits and dresses, and garments such as lining, underwear, swimwear, and sports clothing, as well as handkerchiefs and scarves. The present invention relates to a modified cross-section fiber excellent in light weight, which is suitably used for decorative products such as ties, various vehicle interior materials, and industrial applications such as carpets and curtains.

  In general, since synthetic fibers have a monotonous surface shape, surface reflections reinforce each other, which tends to give a lustrous luster, have a plastic-like feeling, and are likely to be of lower quality than natural fibers. In addition, there is a problem that it is liable to cause a drawback that there is a slimy feeling when it comes into contact with the skin. Therefore, by making the cross section of the fiber an irregular cross section for a long time, it improves the light reflection characteristics on the surface of the fiber, gives the fiber a mild luster, reduces the contact area with the skin and suppresses the slime feeling Research into natural fiber-like fibers has been conducted. In particular, development of synthetic fibers exhibiting silk-like luster, which is representative of high-grade natural fibers, is active, and synthetic fibers having various cross-sectional shapes have been proposed.

  For example, a fiber having a unique texture has been proposed by making the cross-section of a single fiber into a substantially point-symmetric triangular cross section (see Patent Document 1). The irregular cross-section fiber can suppress the slime feeling caused by the monotonous surface shape of the fiber and reduce the discomfort with the skin. As a result, it was a fiber that was easily monotonous and insufficiently glossy.

  In view of this, there has been a proposal that the surface reflection characteristics of the fiber are further improved by imparting micro unevenness to the surface of the fiber so that the fiber exhibits a gloss closer to that of natural fibers.

  For example, a 3-8 leaf type polyester modified cross-section fiber having a streak groove and a microvoid on the surface of the fiber has been proposed for the purpose of expressing a natural silk-like mild luster (see Patent Document 2). . The technology forms a microvoid and a streak-like groove on the fiber surface by reducing the amount of alkali of a modified cross-section fiber composed of polyester, a copolymer polyester having a high dissolution rate in a hot alkaline aqueous solution, and a polymer blended with inorganic particles. The present invention provides a fiber having a mild gloss as compared with a normal multi-leaf type irregular cross-section fiber that does not modify the surface morphology. However, it is only possible to obtain a product that is inferior in quality as compared with a natural product, and this is a technology that has a limit in improving glossiness by modifying the surface shape. In addition, the irregular cross-section and the micro unevenness on the surface that give rise to the glossiness are easily changed by bending, stretching or abrasion of the fiber in actual use, and the glossiness is impaired.

  On the other hand, the demand for lightweight fibers has been increasing year by year in light of the expansion of lightweight clothing due to aging in recent years, the expansion of lightweight or warm clothing due to the popularity and establishment of outdoor sports, and the weight reduction of vehicle interior materials due to energy conservation. Yes. Recently, not only clothing materials but also industrial materials such as car seats and carpets, a high-quality appearance such as natural silk-like luster has been demanded. However, a fiber that sufficiently satisfies both of these characteristics has not been obtained.

  As a technique for imparting light weight to the fiber, a porous hollow fiber in which a hollow portion having a pore diameter of 0.14 μm or more continuous along the fiber axis direction is formed (see Patent Document 3). The technology uses sea water-like composite fibers that are soluble in hot water or alkali in the island-island composite fiber, and has a hollow portion that has a continuous hollow portion along the length of the fiber by eluting the island portion. It can be a hollow fiber. However, since the holes are continuous in the fiber axis direction, the hollow part is easily deformed, and since the size of the hollow part existing in the cross section is the same, the light reflected by the hollow part is strengthened by interference. There is a concern that the fibers are easily glaring and have a synthetic fiber-like appearance even if the cross-sectional shape is an ellipse or a triangular cross-section.

  A lightweight polyester fiber composed of a polyester resin and a styrene / maleimide resin having a molecular weight of 60 to 170,000 has been proposed (see Patent Document 4). It has excellent lightness because it has a large number of fine cavities that appear when the polyester resin and styrene / maleimide resin are peeled off.

  However, since the lightweight polyester fiber is blended with a styrene / maleimide resin having a maleimide structure having a high affinity with polyester, interfacial peeling between the polyester and styrene / maleimide hardly occurs, and void formation is low. Was easily localized at the center of the fiber cross section, and as a result, the glossiness of the fiber was likely to be monotonous. In addition, styrene / maleimide resin is very yellowish due to the maleimide structure, and the fiber itself is prone to yellowing, so it is far from natural silky luster and difficult to use for clothing. .

In order to impart lightness to the fiber, the present inventors already have a sea-island polyester composite fiber composed of polyester and a thermoplastic polymer (excluding polyester) having no maleimide structure, and at least part of the sea-island composite interface has voids. The polyester composite fiber which is excellent in the lightness whose apparent specific gravity of a fiber is 1.2 or less is formed by forming (refer patent document 5). The technology maintains excellent lightness by the presence of a large number of fine voids inside the fiber, and by obtaining fine fibers, the fiber properties are excellent, and lightweight fibers suitable for clothing and industrial applications are obtained. I can do it. The inventors of the present invention have further studied the technique in detail and have a specific configuration, so that in the fiber cross section, the diameter of the void is the diameter of the void from the fiber surface layer portion to the fiber central portion inside the fiber. Has found that it is possible to form a void distribution that changes stepwise. In the present invention, the void distribution in which the diameter of the void changes stepwise is referred to as an inclined structure. Specifically, in the fiber cross section, the diameter of the void existing at each position from the fiber surface layer portion toward the fiber center portion. Means a void distribution that gradually increases. It was also found that the glossiness of the fiber changes significantly by forming such an inclined structure inside the fiber. However, with a simple round fiber, light is easily reflected directly on the fiber surface, and the inclined structure of the voids inside the fiber has not been fully utilized. Further, in the round fiber, the inclined structure of the void in the fiber cross section tends to be isotropic in all directions from the fiber surface layer portion to the fiber center portion, and as a result, the gloss tends to be monotonous.
Japanese Patent Publication No. 36-20770 Japanese Patent Laid-Open No. 11-222725 (Claims, paragraph [0001]) JP-A-8-226209 (Claims, paragraph [0011]) JP 2000-154427 A (claims, paragraph [0012]) JP 2004-183196 A

  The object of the present invention is to solve the above-mentioned problems of the prior art and not only has a gloss and touch with a sense of quality very close to natural silk, but also has good lightness, bulkiness, whiteness, light-shielding properties, and heat retention. Further, the present invention is to provide a modified cross-section fiber excellent in light weight and excellent in product manufacturing process passability and product durability because of excellent durability of fine voids.

  As a result of intensive studies in order to solve the above-mentioned problems, the present invention allows light reflection by the fiber surface by forming an inclined structure of voids inside the blend deformed cross-section fiber composed of a specific polymer composition, It has been found that the light reflection due to the inclined structure of the voids inside the fiber acts synergistically, can overcome the disadvantages of the prior art, and can provide further advantages.

That is, the present invention is a fiber in which two components of polymer A and polymer B that are incompatible with each other are blended, and in the fiber cross section perpendicular to the fiber axis direction, polymer A is a sea and polymer B is an island. The content of polymer B is not less than 1% by weight and not more than 15% by weight based on the total fiber weight, and the relationship between the glass transition temperature TgA of polymer A and the glass transition temperature TgB of polymer B is TgB−TgA ≧ 5 ° C, the cross section of the fiber is a deformed cross section with a degree of deformity of 1.20 or more, and there are many fine voids that are discontinuous in the fiber axis direction inside the fiber, and the circumscribed circle and the inscribed in the fiber cross section A modified cross-section fiber excellent in light weight, characterized in that the average diameter d1 of the fine voids contained between the circles and the average diameter d2 of the fine voids contained inside the inscribed circle satisfy the following formula: It is.
d2 / d1 ≧ 1.30
Apparent specific gravity of fiber ≦ Specific gravity of polymer A × 0.9

  The modified cross-section fiber excellent in light weight according to the present invention has an inclined structure in which the diameter of the voids changes from the fiber surface layer portion to the fiber center portion inside the fiber, and thereby the light from the surface of the irregular cross-section fiber. The reflection and the light reflection due to the inclined structure of the voids inside the fiber act synergistically, and have a gloss with a sense of quality very close to natural silk. Moreover, since the lightness, whiteness, light-shielding property, bulkiness, heat retention and tension / waist are good, and the fabric is formed with voids between the fibers, the above characteristics are further improved. Many fine voids that exist in an inclined manner are discontinuous in the longitudinal direction of the fiber, so that the deformation of the void is suppressed, and the inclined structure of the void does not change even when bent or worn, and the fiber has excellent practical durability Therefore, it can be suitably used not only for clothing but also for industrial materials.

  The fiber in the present invention refers to a thin and long shape, and may be a long fiber (filament) or a short fiber (staple) generally referred to, or a short fiber used for electric flocking, that is, a pile. If it is recognized that it has these fiber shapes, there will be no restriction | limiting in particular.

  The modified cross-section fiber excellent in lightness according to the present invention needs to be a fiber obtained by blending two components of polymer A and polymer B. The blend fiber means a fiber formed from a blend composition in which the polymer A and the polymer B are kneaded at an arbitrary stage before melt spinning is completed by various methods as described later, and the fiber axis direction. In the cross section of the fiber perpendicular to, a sea-island structure in which polymer A forms the sea and polymer B forms an island is formed. Moreover, the polymer B which is an island exists in a streak shape in the fiber axis direction, and the streaks are discontinuous having an appropriate length. Therefore, when the composite interface between polymer A and polymer B in the fiber becomes very large and becomes a lightweight fiber, discontinuous voids are generated with respect to the fiber axis, and the fiber has many fine voids. Polymer B exists in the void.

  Light of various wavelengths incident on the fiber is reflected and transmitted at the interface between the fiber surface layer and the outside of the fiber, the interface between the polymer A and the inside of the gap, the interface between the polymer B and the inside of the gap, or the interface between the polymer A and the polymer B. The light is divided into light, and the transmitted light is refracted corresponding to the refractive index difference at the interface. This phenomenon occurs repeatedly inside the fiber, and the divided lights interfere with each other, and the gloss is sensed by entering the sight. The modified cross-section fiber of the present invention aims to control the light scattering phenomenon, paying attention to the fact that the reflection and transmission phenomena are strongly dependent on the form, size and distribution of the above interface, The glossiness of the fiber is improved by forming the.

  The irregular cross-section fiber of the present invention has a void inclined structure in which the diameter of the void increases stepwise from the fiber surface layer portion to the fiber central portion in the fiber cross section. And the larger the difference between the size of the air gap near the fiber surface layer and the size of the air gap near the fiber center, that is, the greater the inclination tendency, the wider the incident light in the fiber corresponds to the air gap distribution. As a result, light having different wavelengths is reflected, and there is no glossy luster and the gloss is soft and luxurious. Further, since the polymer B is contained inside the fiber, the light is appropriately refracted by the difference in refractive index of the elements forming the interface and does not strengthen, so that the glare can be suppressed. When the cross section of the fiber is an irregular cross section with an irregularity degree of 1.20 or more, the light incident on the fiber is synergistically acted by the light reflection on the fiber surface and the light reflection due to the inclined structure of the gap, and the gloss of the fiber. The sensation exhibits a gloss with a sense of quality close to that of natural silk.

  The modified cross-section fiber excellent in lightness according to the present invention has a higher void forming property as the average dispersion diameter of the polymer B, which is an island component, is smaller, and an inclined structure of voids is more easily exhibited. The average dispersion diameter of the polymer B is preferably 1 μm or less, more preferably 0.8 μm or less, and even more preferably 0.5 μm or less. Further, the lower limit is preferred, but since polymer A and polymer B are incompatible, the current limit is 0.01 μm. The average dispersion diameter can be confirmed by Example H. In addition, when the island component in the fiber is continuous in the fiber axis direction, that is, a core-sheath composite fiber or a sea-island composite fiber, this is not a blend fiber, but a composite interface (interface between the core and the sheath or the interface between the sea and the island) The area of the fiber is extremely small compared to the blended fiber, and no voids are formed, or even if they are formed, the inclined structure of the voids of the present invention does not appear. This is not preferable.

  The modified cross-section fiber excellent in lightness of the present invention needs to have discontinuous fine voids in the fiber axis direction. By having voids that are discontinuous in the fiber axis direction, the gloss becomes mild and the lightness is excellent. Further, since the voids are fine, the fiber strength is also good. If the fine voids are not discontinuous in the fiber axis direction, the voids are liable to be crushed by an external force, and it is difficult to maintain the glossiness or lightness of the fibers. The discontinuity of the voids can be confirmed by a single fiber cross-sectional photograph and a vertical cross-sectional photograph observed by the method I in the section of Examples.

  The fine voids that are discontinuous in the fiber axis direction can be formed by the method exemplified later.

  The modified cross-section fiber excellent in lightness according to the present invention needs to have a gap inclined structure. Here, the inclined structure means that there is a void distribution in which the diameter of the void existing at each position gradually increases from the fiber surface layer portion toward the fiber center portion in the fiber cross section, On the surface, the average diameter d1 of the fine voids existing in the area included in the circumscribed circle and the inscribed circle of the fiber cross section described later, and the average diameter d2 of the fine voids present in the area included in the inscribed circle When the diameter ratio d2 / d1 is 1.30 or more, it is defined as having an inclined structure. d1 and d2 are calculated by image analysis using the fiber cross-sectional photograph obtained by the method of Example I. In order to make the gloss of the fiber milder, d2 / d1 ≧ 1.5 is preferable, and d2 / d1 ≧ 1.8 is more preferable. More preferably, d2 / d1 ≧ 2.0. The upper limit of d2 / d1 is not particularly limited, but about 1000 or less is appropriate. For example, in the case of the three-leaf type irregular cross-section fiber shown in FIG. 1, the region encompassed by the circumscribed circle and the inscribed circle is denoted by 3, and the region encompassed by the inscribed circle is denoted by 4.

  Moreover, in this invention, it is necessary to make a fiber cross-sectional shape into an irregular cross section. The light reflection by the inclined structure and the light reflection by the irregular cross section act synergistically, and the glossiness of the fiber is dramatically improved. This is due to the light reflection polarization characteristic of the irregular cross section and the inside of the fiber. It is presumed that the glossiness is remarkably improved because the light reflected from the respective gaps reflected by the inclined structure of the gaps interferes moderately.

  Moreover, the inclined structure of the irregular cross-section fiber of the present invention may have anisotropy. It is preferable to have an inclined structure having anisotropy in the cross section of the fiber, because light incident on the fiber from multiple directions is reflected by the various inclined structures of the gaps, and the gloss of the fiber becomes milder. The inclined structure having anisotropy in the present invention means an inclined structure of voids existing in the direction of the line segment (11) connecting the contact point of the circumscribed circle and the center of gravity in the cross section of the single fiber, and the contact point and center of gravity of the inscribed circle. It means that the inclined structure of the voids existing in the direction of the line segment (12) connecting the two is different. When the number of voids intersecting or in contact with l1 (nl1) and the average diameter of the voids (dl1) are different from the number of voids intersecting or in contact with l2 (nl2) and the average diameter of the voids (dl2), It is judged that the inclined structure of the gap has anisotropy. From the viewpoint of making the fiber gloss milder, nl1 / nl2 ≧ 1.1 is preferable, and nl1 / nl2 ≧ 1.3 is more preferable. For the same reason, the relationship between dl1 and dl2 is preferably dl1 / dl2 ≧ 1.1, and more preferably dl1 / dl2 ≧ 1.3.

  The modified cross-section fiber excellent in lightness of the present invention needs to have many fine voids. Here, having a large number of fine voids means that there must be at least 100 voids in the observation of voids in the fiber cross section described later. The presence of many voids having different diameters forms a dense inclined structure in the fiber cross-sectional direction, and for the first time, the fibers exhibit a mild and high-grade luster. And since this void has a discontinuous shape in the fiber axis direction, the durability of the void is improved, and the effect of the cushion is achieved without collapsing this fine void, so that the fiber cross-sectional shape, void The inclined structure is not easily changed, and various properties such as glossiness and lightness are not impaired in actual use. Furthermore, the fibers of the present invention are not easily crushed even in processing steps such as drawing and false twisting, and exhibit sufficient lightness. The number of voids present in the fiber cross section is preferably 300 or more, more preferably 1000 or more, and even more preferably 10,000 or more. The upper limit of the number of voids is not particularly limited, but about 1,000,000 is appropriate. The number of voids can be confirmed by the method of Example I below.

  In the modified cross-section fiber excellent in light weight of the present invention, the voids are not easily crushed and the glossiness of the fiber or the lightness is easily maintained, so that the average diameter of the fine voids existing in the single yarn cross section is 0.01 μm. It is preferable to exceed. The average diameter of the fine voids is preferably 0.03 μm or more, and more preferably 0.05 μm or more, from the viewpoint of better lightness. However, since the fiber strength may be lowered when the voids become too large, the average diameter of the fine voids is preferably 5 μm or less, more preferably 1 μm or less, and particularly preferably 0.5 μm or less. preferable. The average diameter of the fine voids can be calculated by the method of Example I below.

  The porosity indicating the proportion of voids in the modified cross-section fibers excellent in lightness of the present invention is such that the modified cross-section fibers of the present invention are more lightweight and the porosity is 15% or more. Preferably, it is 25% or more. Here, the porosity can be calculated by measuring the apparent specific gravity of the fiber by the method of Example F below.

  The fiber of the present invention is required to have an irregular cross section having an irregularity of 1.20 or more in the fiber cross section. The method of calculating the irregularity will be described later. Here, the fiber cross section is a cross section orthogonal to the fiber axis direction, and the irregular cross section is a cross section of a single fiber cross section having an irregularity of 1.20 or more. Refers to a cross section. Only when the degree of irregularity is 1.20 or more, the light reflection due to the irregular cross section and the light reflection due to the voids inside the fiber act synergistically, and natural silk-like mild luster appears. In addition, due to the irregular cross section, the contact area with the skin is reduced and the touch feeling is excellent, and a dry touch has a high-class texture such as a squeaky feeling or a sharp feeling. If the degree of profile is less than 1.20, more light is directly reflected on the fiber surface, which is not preferable because gloss is monotonous without taking full advantage of the gloss improvement effect of the inclined structure. The greater the degree of deformity, the more the light incident on the fiber enters the interior without being directly reflected by the fiber surface, and the inclination tendency of the air gap itself increases, and the synergistic effect of the irregular cross section and the inclined structure tends to appear. Therefore, the degree of irregularity is more preferably 1.3 or more, even more preferably 1.4 or more, and particularly preferably 1.5 or more. The upper limit is not particularly limited, but is preferably 7.00 or less, and preferably 5.00 or less in terms of fiber form and gloss durability, void formation, or fiber strength and process passability. Is more preferably 3.00 or less, and particularly preferably 2.00 or less.

  The degree of irregularity in the present invention is defined as the ratio (D1 / D2) of the diameter D1 of the circumscribed circle and the diameter D2 of the inscribed circle in the single fiber cross section. The irregular cross-section may be a shape that maintains symmetry such as line symmetry or point symmetry, or may be asymmetric, but it is generally symmetrical in terms of having uniform fiber properties. Is preferred. When it is judged that the irregular cross section generally retains line symmetry and point symmetry, the inscribed circle is a circle inscribed in the curved line that forms the profile of the irregular cross section fiber in the single fiber cross section, and the circumscribed circle is a single fiber. It is a circle that circumscribes a curve that defines the profile of the irregular cross-section fiber in the cross section. For example, the degree of irregularity of the three-leaf shaped irregular cross-section fiber shown in FIG. 1 is calculated using the diameter D1 of the circumscribed circle 1 and the diameter D2 of the inscribed circle 2. In addition, when it is determined that the irregular cross section 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 profile of the irregular cross section fiber, and exists only inside the fiber. A circle having the maximum radius that can be taken in a range in which the circumference of the inscribed circle does not intersect with the curved line forming the profile of the irregular cross-section fiber is defined as the inscribed circle. The circumscribed circle circumscribes at least two points in the curve showing the profile of the irregular cross-section fiber, exists only outside the cross-section of the single fiber, and is the smallest possible in the range where the circumference of the circumscribed circle and the profile of the irregular cross-section fiber do not intersect A circle having a radius is defined as a circumscribed circle. In addition, the hollow fiber which has a single or several hollow part which exists continuously in the longitudinal direction of the fiber and has no communication with the outside of the fiber is not included in the modified cross-section fiber of the present invention.

  The shape of the single fiber cross section of the modified cross-section fiber excellent in light weight according to the present invention is not particularly limited, and can take various cross-sectional shapes. For example, general names include shapes such as a polygonal shape, a gear shape, a petal shape, a multileaf shape, a star shape, and a C shape. A multi-leaf type, a polygonal type, a gear type, and a star shape are preferable, and a multi-leaf type is more preferable in that the fiber has a more glossy feeling. A multi-leaf type cross-section refers to one having irregularities in the cross-section and the same number of concave and convex portions, and a multi-leaf type cross-section fiber in which a multi-leaf type cross-section is continuously formed in the longitudinal direction is a fiber The light reflected on the surface again enters the inside of the fiber, and it is easy to take advantage of the gloss improvement effect due to the inclined structure inside the fiber, and it is easy to form anisotropy in the inclined structure of the voids existing in the fiber cross section. The luster of the film becomes very mild and natural silk tone is preferable. In addition to having a small contact area with the skin, it is easy to maintain a high-quality texture such as dry touch, crispness, sharpness, and swelling, as well as characteristics such as lightness, whiteness, bulkiness, and heat retention. Is also preferable.

  When the cross-sectional shape of the irregularly-shaped cross-section fiber in the present invention is a multileaf type, the upper limit and lower limit of the number of leaves are not particularly limited, but it is more excellent in silky luster and has a small contact area with the skin. It is preferably 3 or more leaves in that it has a dry touch texture and is light in weight. On the other hand, in consideration of the spinnability and the fiber properties of the resulting fiber, or the fact that the cross-sectional shape is easily maintained, it is preferably a multi-leaf type irregular cross section having 8 or less leaves, and a multi-leaf type cross section having 6 or less leaves. Even more preferably.

  It is preferable that the modified cross-section fiber of the present invention having excellent lightness has a skin layer without voids on the fiber surface. By having the skin layer, the fiber is not scraped by bending or abrasion, and the durability of the inclined structure existing inside the fiber is further increased. Moreover, since the resilience of a fiber and fiber strength improve, it is preferable. Thereby, it can be used suitably also as material uses, such as a sheet | seat and carpet which require abrasion resistance. If the thickness of the skin layer is too thick, the volume in which voids are formed inside the fiber is reduced, and as a result, the fiber is inferior in gloss or lightness. Therefore, the thickness of the skin layer is 1 / D of the diameter D1 of the circumscribed circle. It is preferably 5 or less, more preferably 1/10 or less, and even more preferably 1/15. Moreover, since the effect of a skin layer will be lose | eliminated when too thin, it is preferable that it is 1/10000 or more of D1. This skin layer can be formed at the same time as the voids described later are formed. Therefore, this skin layer is composed of a blend polymer of polymer A and polymer B.

  Moreover, in order to give the fiber a water-absorbing property, a moisture-releasing property, or a more soft and dry touch feeling, a structure having voids on the fiber surface by a technique such as alkali weight reduction processing may be used. Such a structure is preferable because, for example, moisture absorption / release, water absorption, moisture release, and heat retention are further improved. For example, with respect to moisture absorption / release properties, when using the modified cross-section fibers of the present invention as part or all of the textile products for clothing, a more comfortable wearing feeling can be obtained without stickiness when worn, so the hygroscopic index The hygroscopic index (ΔMR) is preferably 0.3% or more, and more preferably 0.5% or more. Specifically, ΔMR is a value obtained by subtracting the moisture absorption rate (MR1) at 20 ° C. and 65% RH from the moisture absorption rate (MR2) at 30 ° C. and 90% RH (ΔMR (%) = MR2). -MR1). The temperature in clothes when light or moderate work or exercise is performed is represented by 30 ° C. and 90% RH, and the outside air temperature is represented by 20 ° C. and 65% RH, and the difference between the two is taken. The larger the ΔMR, the higher the moisture absorption / release capacity, and the better the comfort when worn.

  The polymer A which forms the modified cross-section fiber excellent in light weight according to the present invention is not particularly limited as long as it has fiber forming ability. Polyester polymers and polyamide polymers can be used as polymers for general use. Polyimide polymers, polyolefin polymers, other vinyl polymers, fluorine polymers, cellulose polymers, silicone polymers, elastomers, and various other engineering plastics.

  More specifically, for example, in polyolefin polymers and other vinyl polymers synthesized by a mechanism in which a monomer having a vinyl group such as radical polymerization, anionic polymerization, and cationic polymerization is generated by an addition polymerization reaction, polyethylene, polypropylene , Polybutylene, polymethylpentene, polystyrene, polyacrylic acid, polymethacrylic acid, polymethyl methacrylate, polyacrylonitrile, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene chloride, poly (vinylidene chloride), etc. For example, it may be a polymer obtained by homopolymerization such as polyethylene alone or polypropylene alone, or a copolymer polymer formed by conducting a polymerization reaction in the presence of a plurality of monomers. Well, for example, styrene and Doing polymerization in methyl methacrylate presence poly - but polymers copolymerized as (styrene methacrylate) is produced, it may be a polymer which is such a copolymer.

  Further, for example, polyamide polymers formed by the reaction of carboxylic acid or carboxylic acid chloride and amine can be mentioned. Specifically, nylon 6, nylon 7, nylon 9, nylon 11, nylon 12, nylon 6,6. Nylon 4,6, Nylon 6,9, Nylon 6,12, Nylon 5,7, Nylon 5,6 and the like, and other aromatics, aliphatics, alicyclics as long as they do not impair the gist of the present invention Aromatic dicarboxylic acid and aromatic, aliphatic, alicyclic diamine component, or one compound such as aromatic, aliphatic, alicyclic, etc., used alone is an aminocarboxylic acid compound having both carboxylic acid and amino group It may be a polyamide polymer in which the third and fourth copolymer components are copolymerized.

  Moreover, for example, a polyester polymer formed by esterification reaction of carboxylic acid and alcohol can be mentioned. Specifically, the polyester polymer referred to in the present invention is not particularly limited, and examples thereof include a polymer formed from an ester bond of a dicarboxylic acid compound and a diol compound. Examples thereof include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polycyclohexanedimethanol terephthalate. Although not particularly limited, the polyester polymer formed from the ester bond of the dicarboxylic acid compound and the diol compound may be copolymerized with other components within a range not impairing the gist of the present invention. As the dicarboxylic acid compound of the copolymer component, for example, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, anthracene dicarboxylic acid, phenanthrene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenylethane dicarboxylic acid, Adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, azelaic acid, dodecanedioic acid, hexahydroterephthalic acid, etc. Aromatic, aliphatic, and alicyclic dicarboxylic acids and their alkyl, alkoxy, allyl, aryl, amino, imino, and halide derivatives, adducts, structural isomers, optical isomers, and the like. Among the acid compounds, one kind may be used alone, or two or more kinds may be used in combination as long as the gist of the invention is not impaired.

  Examples of the copolymer component include diol compounds such as ethylene glycol, propylene glycol, butylene glycol, pentanediol, hexanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, hydroquinone, resorcin, dihydroxybiphenyl, naphthalenediol, anthracene. Aromatic, aliphatic and alicyclic diol compounds such as diol, phenanthrenediol, 2,2-bis (4-hydroxyphenyl) propane, 4,4′-dihydroxydiphenyl ether, bisphenol S, and their alkyl, alkoxy, allyl, Derivatives, adducts, structural isomers, and optical isomers such as aryl, amino, imino, and halide can be listed. One of these diol compounds can be used alone. Also it may be, or in a range that does not impair the gist of the invention may be used in combination of two or more.

  Examples of the copolymer component include a compound having a hydroxyl group and a carboxylic acid in one compound, that is, a hydroxycarboxylic acid. Examples of the hydroxycarboxylic acid include lactic acid, 3-hydroxypropionate, and 3-hydroxybutyrate. Aromatic, aliphatic and alicyclic diol compounds such as acrylate, 3-hydroxybutyrate valerate, hydroxybenzoic acid, hydroxynaphthoic acid, hydroxyanthracenecarboxylic acid, hydroxyphenanthrenecarboxylic acid, (hydroxyphenyl) vinylcarboxylic acid, and their Derivatives, adducts, structural isomers and optical isomers such as alkyl, alkoxy, allyl, aryl, amino, imino, and halide can be mentioned, and one of these hydroxycarboxylic acids may be used alone. Or invention It may be used in combination of two or more in a range that does not impair the gist.

  Further, the polyester polymer may be a polymer in which one compound such as aromatic, aliphatic, alicyclic, etc. is mainly composed of a hydroxycarboxylic acid compound having both a carboxylic acid and a hydroxyl group as a main repeating unit. For example, polylactic acid, poly (3-hydroxypropionate), poly (3-hydroxybutyrate), poly (3-hydroxybutyrate validate), etc. Poly (hydroxycarboxylic acid) can be mentioned, and other than these, poly (hydroxycarboxylic acid) can be aromatic, aliphatic, alicyclic dicarboxylic acid, or aromatic as long as the gist of the present invention is not impaired. , Aliphatic and alicyclic diol components may be used, or plural types of hydroxycarboxylic acids are copolymerized It may be.

  Other polymers having fiber-forming ability of the present invention include polycarbonate polymers formed by transesterification of alcohol and carbonic acid derivatives, polyimide polymers formed by cyclization polycondensation of carboxylic acid anhydrides and diamines, and dicarboxylic acids. Synthesis of polybenzimidazole polymers formed by the reaction of acid esters and diamines, as well as polysulfone polymers, polyether polymers, polyphenylene sulfide polymers, polyetheretherketone polymers, polyetherketoneketone polymers Examples also include polymers derived from natural polymers such as polymers, cellulosic polymers, chitin and chitosan derivatives.

  For these polymers A, as will be described later, it is preferable that the critical surface tension γcA is large, the tension at the time of stretching is small, and the voids are easily developed at the time of stretching. A polyester polymer is more preferable because it can be stretched with a low stretching tension during stretching. Of these polyester polymers, polyester polymers in which the main repeating unit is ethylene terephthalate, propylene terephthalate, butylene terephthalate, or lactic acid are preferred in that they are more versatile and have excellent fiber-forming properties, and the main repeating unit is ethylene terephthalate. More preferred are polyester polymers. These polyamide polymers such as nylon 6 or polyester polymers such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate both have a critical surface tension γcA of about 43 dyne / cm.

  As the polyester polymer preferable as the polymer A of the present invention, a polyester having an intrinsic viscosity (IV) usually used for a synthetic fiber can be used. Although the lower limit and the upper limit of IV are not particularly limited, for example, when the polymer A and the polymer B are melt-kneaded, a high shear stress is expressed, and as a result, the polymer B is refined in the fiber, and the void forming property is increased. In terms of excellence, for example, polyethylene terephthalate is preferably 0.4 or more, and more preferably 0.5 or more. If it is a polypropylene terephthalate, it is preferable that it is 0.7 or more, and it is more preferable that it is 0.8 or more. If it is polybutylene terephthalate, it is preferably 0.6 or more, more preferably 0.7 or more. Although the upper limit is not particularly limited, it is 1.5 or less for polyethylene terephthalate, for example, in that the meterability of the gear pump is good, there is no unevenness in fineness, and the fiber does not become excessively hard. Is more preferable and 1.3 or less is more preferable. If it is a polypropylene terephthalate, it is preferable that it is 2.0 or less, and it is more preferable that it is 1.8 or less. If it is polybutylene terephthalate, it is preferable that it is 1.5 or less, and it is more preferable that it is 1.4 or less. Polyesters used in the present invention include poly (hydroxycarboxylic acids) represented by polylactic acid that are not evaluated in IV, and these are described in terms of weight average molecular weight (hereinafter sometimes simply referred to as average molecular weight). For example, in the case of polylactic acid, those having an average molecular weight of 50,000 to 500,000 are usually used, preferably 100,000 to 300,000, and an average of 150,000 to 250,000 in view of processability and spinnability Molecular weight polylactic acid is more preferably used.

  The content of the polymer A in the modified cross-section fiber excellent in light weight of the present invention is not particularly limited as long as it is 50% by weight or more, and any content can be taken. In particular, since the fiber strength is preferably high in the fiber properties, the polymer A content in the fiber is preferably 70% by weight or more, more preferably 80% by weight or more, and even more preferably 85% by weight or more. is there.

  As the polymer A, one kind of polymers selected from these may be used alone, or a plurality of kinds may be used in combination as long as the gist of the invention is not impaired.

  Since the polymer B in the present invention forms a blend fiber with the polymer A and forms an island in the fiber cross section, the polymer A and the polymer B are incompatible with each other. Here, “incompatible” means that polymer A and polymer B are not compatible with each other in the molecular chain size order of the polymer, and the average diameter of island components formed by polymer B in polymer A (the following examples) Calculated by the method of H) refers to those having a size of at least 10 nm. When the polymer A and the polymer B are compatible, that is, when the average domain size formed by the component B is 10 nm or less, although the polymer A and the blended fiber are formed, the aforementioned island formed by the polymer B is excessively small. In addition, it does not have voids, or even if voids are formed, the inclined structure of the voids necessary for exhibiting silk-like luster is not sufficiently exhibited, resulting in a modified cross-section fiber having poor glossiness, which is not preferable.

  The polymer B of the present invention is not particularly limited as long as it is incompatible with the polymer A as described above, and a wide variety of polymers can be used. For example, polyamide polymer, polyolefin polymer and other vinyl polymers, fluorine polymer, silicone polymer, elastomer, polycarbonate polymer, polyimide polymer formed by cyclization polycondensation of carboxylic acid anhydride and diamine, dicarboxylic acid Polybenzimidazole polymers formed by the reaction of esters and diamines, polysulfone polymers, aliphatic polyether polymers, aromatic polyether polymers, polyphenylene sulfide polymers, polyetheretherketone polymers, polymers Examples thereof include synthetic polymers such as ether ketone ketone polymers, cellulose polymers, polymers derived from natural polymers such as chitin and chitosan derivatives, and various other engineering plastics.

  More specifically, for example, polyolefins and other vinyl polymers synthesized by a mechanism in which a monomer having a vinyl group such as radical polymerization, anionic polymerization, or cationic polymerization is formed by addition polymerization reaction or ring-opening polymerization reaction. In the case of polyolefins, homopolymers, copolymers, and derivatives of polyethylene, polypropylene, polybutylene, and polymethylpentene can be used as polyolefins, and polystyrene, polyacrylic acid, polymethacrylic acid can be used as other vinyl polymers. , Polymethyl methacrylate, polyacrylonitrile, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene chloride, poly (vinylidene cyanide), and copolymers and derivatives thereof. Among the polymer synthesized by polymerization reaction, the critical surface tension described later, preferable from the viewpoint of density or glass transition temperature Tg,, it can be mentioned first polyolefin polymer.

  Among the preferred polyolefin-based polymers, first, as a polyolefin mainly composed of olefins, for example, ethylene, propylene, butene, methylbutene, methylpentene, ethylpentene, hexene, ethylhexene, octene, decene, tetradecene, octadecene as monomers In addition to the polyolefin used as the polymer, a polyolefin polymer having a cyclic structure represented by the following chemical formula 1, chemical formula 2, or chemical formula 3, for example, synthesized by ring-opening polymerization or addition polymerization of an alicyclic monomer can be given.

  Here, each of the substituents X and Y is a group selected from hydrogen, an alkyl group, an alicyclic group, a cyano group, an alkyl ester group, and an alicyclic ester group.

  Examples of those having the structure include polyolefins having a cyclic structure, such as Arton (registered trademark) manufactured by JSR Corporation, Zeonoa (registered trademark) manufactured by Nippon Zeon Co., Ltd., and Zeonex (registered trademark). However, it is not limited to these.

  These polyolefin polymers may be homopolymers using one kind of monomer alone, or may be a copolymer using two or more kinds, and further copolymerize olefins with other vinyl compounds. It may be a copolymer. Specific examples of the copolymer component include vinyl esters of saturated aliphatic carboxylic acids having 2 to 6 carbon atoms, acrylic acid esters and methacrylic acid esters derived from alcohols having 1 to 20 carbon atoms, Unsaturated carboxylic acids such as fumaric acid, maleic acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, nadic acid, acid halides, amides, imides, acid anhydrides and esters of the unsaturated carboxylic acids, Examples thereof include vinyl compounds such as styrene or styrene derivatives, acrylonitrile or acrylonitrile derivatives, vinyloxyalkyl derivatives (alcohol type or carboxylic acid type), or vinyl compounds having an alicyclic structure. In particular, examples of the polyolefin-based polymer having the alicyclic structure as a copolymerization component include Apel (registered trademark) manufactured by Mitsui Chemicals, Inc. and TOPAS (registered trademark) manufactured by Polyplastics Co., Ltd. The copolymerized polyolefin polymer having a ring structure is not limited to this.

  Among the polyolefin polymers exemplified as preferred among these polymers B, propylene and / or methylpentene are preferred in that the formed fiber has a high void forming property and an inclined structure of voids is easily formed in the fiber cross section. A polyolefin polymer having a main repeating unit, a polyolefin polymer having a cyclic structure, or a copolymerized polyolefin polymer having an alicyclic structure is preferred.

  Further, examples of the polymer B of the present invention include polyether polymers in addition to the polyolefin polymers, and among them, aromatic polyether polymers represented by polyphenylene ether are preferable. The polyphenylene ether may be a homopolymer mainly composed of phenylene oxide, or may be a copolymer obtained by copolymerizing the second component, and may be added within the range not impairing the gist of the invention. It may be a modified polyphenylene ether alloyed with a contained component, that is, a polystyrene polymer, a polyamide polymer, a polyester polymer, a polyolefin polymer, or the like as a second component. Examples of the modified polyphenylene ether include Iupiace (registered trademark) and Remalloy (registered trademark) manufactured by Mitsubishi Engineering Plastics Co., Ltd., Noryl (registered trademark) manufactured by GE Plastics Co., Ltd., and Asahi Kasei Co., Ltd. Zylon (registered trademark), Art Rex (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., Artley (registered trademark), and the like. Needless to say, aromatic polyether polymers listed as preferred polymers are limited to these. Is not to be done.

  Alternatively, the polymer B in the present invention is preferably a polycarbonate polymer. The polycarbonate polymer may be a homopolymer mainly composed of bisphenol A and C═O, or may be a copolymer obtained by copolymerizing the third component, and the gist of the invention is impaired. As long as there are no additives, it may be a modified polycarbonate in which an additive is added, that is, an alloyed polystyrene polymer, polyamide polymer, polyester polymer, polymethacrylate polymer or the like. Examples of the modified polycarbonate include Iupilon (registered trademark), Novalex (registered trademark) manufactured by Mitsubishi Engineering Plastics, Lexan (registered trademark) manufactured by GE Plastics, and Sumitomo Dow Co., Ltd. Caliber (registered trademark), Panlite (registered trademark) manufactured by Teijin Chemicals Ltd., Taffron (registered trademark) manufactured by Idemitsu Petrochemical Co., Ltd., etc. The polymer is not limited to these.

  The polymer B in the present invention preferably does not have a maleimide structure because the fiber itself is preferably not yellowish. In general, the maleimide structure is a structure obtained by reaction of maleic anhydride with ammonia or a primary amine, and there is a structure such as N-alkylmaleimide, N-cycloalkylmaleimide, or N-phenylmaleimide. An N-phenylmaleimide structure is known as an easy-to-treat material. When the polymer B has the maleimide structure, it is generally yellowish derived from the maleimide structure. Therefore, the fiber itself blended with the polymer A tends to be yellowish, and as a result, the use is limited, which is not preferable. When a polyester polymer is used as the polymer A, the maleimide structure has particularly high affinity with the polyester polymer, so that the affinity at the interface between the polymer A and the polymer B becomes too high, resulting in poor void formation. easy. Although the reason is not well understood, in this case, voids are likely to be formed mainly at the center portion of the fiber cross section, and the voids are localized, making it difficult to form an inclined structure. In addition, sufficient lightness may not be exhibited. When a polymer having a maleimide structure is used as the polymer B to exhibit sufficient lightness, on the contrary, the fiber strength tends to be low and may not be practically used. In particular, when the polymer A is a polyester and the polymer B has a maleimide structure and has a maleic anhydride residue, the polyester and the polymer B are likely to react with each other, and lightness is hardly exhibited anymore or the lightness is low. Even if it is expressed, the fiber strength is remarkably inferior. Examples of the polymer having a yellowish maleimide structure include styrene maleimide polymer (type: MS-NA, etc.) manufactured by Electrochemical Co., Ltd.

  The refractive index nB of the polymer B in the modified cross-section fiber of the present invention is preferably 1.55 or less. The low refractive index of the polymer B existing inside the fiber gap is preferable because the light incident on the gap is not totally reflected and easily reaches the center of the fiber, and the gloss improvement effect by the inclined structure of the gap becomes high. For example, in the present invention, it is preferably 1.51 to 1.54 for a polyolefin-based polymer having a cyclic structure, which is preferable as the polymer B, 1.47 to 1.50 for polypropylene, and polyethylene. 1.51 to 1.54, and 1.463 for polymethylpentene. The refractive index is calculated by the method of Example M.

  The refractive index nA-nB of polymer A, which is the difference in refractive index between polymer A and polymer B, is preferably 0.010 or more. When light is incident on the fiber from the surface, the fiber is easily glared if total reflection occurs on the surface of the fiber. Lowering the apparent refractive index of polymer A, which is the main component of the fiber, is preferable because light enters inside and the gloss improvement effect due to the inclined structure of the voids is enhanced. It is preferable that the polymer A and the polymer B have an appropriate refractive index difference because light is refracted at the interface and the wavelength distribution is changed, specific wavelengths are not intensified, and a milder gloss is exhibited. The refractive index difference is more preferably 0.015 or more, and still more preferably 0.020 or more. The upper limit is not particularly limited, but about 0.200 is appropriate.

  The average molecular weight of the polymer B of the present invention is not particularly limited, but is excellent in kneadability with the polymer A, forms fine island components in the fiber, and makes the fiber physical properties uniform. The number average molecular weight is preferably from 2,000 to 10,000,000, more preferably from 5,000 to 5,000,000, and even more preferably from 10,000 to 1,000,000.

The amount of the polymer B of the present invention will become more inclined structure in the resulting fiber voids formed in that glossiness is excellent, it must be 1 wt% or more, preferably 2 wt% or more . Also because it can lead to a decrease in the fiber strength much added amount is large, it is necessary that 15% by weight or less.

  As the polymer B in the present invention, one kind of these polymers may be used alone, or a plurality of kinds may be used in combination as long as the gist of the invention is not impaired. Moreover, you may mix | blend polymers other than the polymer A and the polymer B with the unusual cross-section fiber excellent in the lightweight property of this invention in the range which does not inhibit the effect of this invention. ΓcA-γcB, which is the difference between the critical surface tension γcA of the polymer A of the present invention and the critical surface tension γcB of the polymer B, represents the affinity at the interface between the polymer A which is the sea component of the fiber and the polymer B which is the island component. The larger γcA-γcB is, the higher the interfacial peelability between polymer A and polymer B is, the better the void formation, and the easier it is to form an inclined structure of voids in the fiber cross section. Although not particularly limited, γcA−γcB ≧ 5 dyne / cm is preferable, and 10 dyne / cm or more is more preferable. However, if the γcA-γcB is too large, the interfacial affinity between the polymer A and the polymer B is low, so that the dispersion form of the polymer B which is an island component in the fiber is likely to be coarsened, and the number of voids in the fiber is reduced. There is a concern that the physical properties will also decrease. Therefore, γcA−γcB ≧ 25 dyne / cm is preferable, and γcA−γcB ≧ 20 dyne / cm is more preferable.

  As a combination of polymer A and polymer B satisfying γcA−γcB ≧ 5 dyne / cm, which is preferable in the present invention, for example, polyester including polyethylene terephthalate and polypropylene terephthalate is polymer A, and polyethylene, polypropylene, and polymethyl are used. Examples include a combination of pentene and polyolefin having a cyclic structure such as polyolefin B as a polymer B, or a combination of polyamide 6 such as nylon 6 or nylon 66 as polymer A and the above polyolefin as polymer B. A combination in which terephthalate or polypropylene terephthalate is polymer A and polymethylpentene or polyolefin having a cyclic structure is polymer B is more preferable.

In addition, the polymer B of the present invention peels easily at the interface with the polymer A to form voids, and the resulting fiber is more lightweight, so that the critical surface tension γcB of the polymer B is 10 to 10%. It is preferably 35 dyne / cm, more preferably 10 to 33 dyne / cm. As the polymer B satisfying this critical surface tension γcB range, among the polyolefins composed of the above-mentioned olefin monomers or other ethylenically unsaturated compounds, 80 mol of polyolefin having propylene and / or methylpentene and / or a cyclic structure is used. % Homopolymer or copolymer is preferred, methylpentene accounts for 80 mol% or more homopolymer or copolymer is more preferred, and in the combination of polyester as polymer A, the void formation is very excellent, Very preferable. In particular, in the case of a homopolymer or copolymer in which the above-mentioned propylene accounts for 80 mol% or more, 29 to 30 dyne / cm, and in the case of a homopolymer or copolymer in which methylpentene accounts for 80 mol% or more, 24 to 25 dyne / cm. cm, 30 to 32 dyne / cm in the case of a homopolymer or copolymer in which the polyolefin having a cyclic structure occupies 80 mol% or more. Further, Polymer A and Polymer B of the present invention, (Tg of the polymer A) the difference between each of the glass transition point Tg TgB (Tg of the polymer B) TGA Ru ≧ 5 ° C. der. When the relationship between the glass transition temperatures satisfies TgB-TgA ≧ 5 ° C., the deformation of the polymer B existing in the polymer A is difficult to occur in the drawing process, so that the composite interface between the polymer A and the polymer B is easy to peel off. It is preferable because voids are formed in the layer and the void forming property is high. Moreover, when TgB-TgA ≧ 5 ° C. is satisfied, the spinning stress applied in the melt spinning process can be mainly borne by the polymer B, and the molecular orientation of the polymer A is suppressed, so-called orientation suppressing effect is expressed, and high It is preferable because magnification can be stretched and there is a merit that it is excellent in productivity. Further, since the polymer B is elongated and refined in the spinning process, the number of interfaces between the polymer A and the polymer B is increased, and a large number of fine voids are generated during stretching, which is preferable. For the above reasons, TgB-TgA ≧ 10 ° C. is more preferable, TgB-TgA ≧ 30 ° C. is further preferable, and TgB-TgA ≧ 50 ° C. is particularly preferable. The upper limit of TgB-TgA is 400 ° C. from the viewpoint of melt moldability, preferably TgB-TgA ≦ 300 ° C., and more preferably TgB-TgA ≦ 200 ° C.

  The Tg of the polymer A is preferably 40 ° C. or higher, and preferably 50 ° C. or higher, in order to avoid heat resistance of the fiber, that is, the polymer A is deformed and the voids are crushed at high temperatures. More preferably, it is more preferably 60 ° C. or higher. Further, the Tg of the polymer B is 70 ° C. or higher in that the heat resistance of the fiber, that is, the polymer B is deformed in the gap to fill the gap even when the fiber is exposed to a high temperature. It is preferably 100 ° C. or higher, more preferably 130 ° C. or higher.

  The combination of polymer A and polymer B satisfying TgB-TgA ≧ 5 ° C., which is preferable in the present invention, is not particularly limited. For example, polyesters including polyethylene terephthalate, polypropylene terephthalate, polylactic acid, and the like , Nylon 6 and nylon 66 as a polymer A, polystyrene, polymethacryl methacrylate, polycarbonate, polyolefin having a cyclic structure, polyphenylene ether as a polymer B, and the like. Polyethylene terephthalate, nylon 6 and nylon 66 are polymers A, and polystyrene, polyolefins with a cyclic structure, and polyphenylene ether are used for their high stability and high void formation. The combination according to Ma B is more preferred. The glass transition temperature of each polymer is given in Example C.I. For example, about 79 ° C. for polyethylene terephthalate, about 47 ° C. for polypropylene terephthalate, about 24 ° C. for polybutylene terephthalate, about 58 ° C. for polylactic acid, Nylon 6 is observed at 71 ° C.

  Although the polymer A and the polymer B of the present invention are not particularly limited, the relationship between the melting point TmA of the polymer A and the melting point TmB of the polymer B is preferably TmA> TmB. When the relationship between the melting points satisfies TmA> TmB, the polymer B is easy to finely disperse with respect to the polymer A, and the void developability is improved. The polymer A of the present invention is not particularly limited, but the heat resistance of the fiber obtained by the method of the present invention, that is, the polymer A is deformed at high temperatures and the voids are crushed. The melting point TmA of A is preferably 160 ° C. or higher, more preferably 210 ° C. or higher, and even more preferably 250 ° C. or higher. Further, the polymer B of the present invention has good heat resistance of the fiber, that is, even when the fiber obtained by the method of the present invention is exposed to a high temperature, the polymer B is deformed in the void to fill the void. In terms of avoidance, the melting point TmB of the polymer B is preferably 150 ° C. or higher, and more preferably 180 ° C. or higher.

The melt viscosity of the polymer B of the present invention is not particularly limited, and a polymer having a shear rate of 10 sec ^{−1 and} a shear viscosity of 10 to 100000 poise is usually used at the melt spinning temperature of the polymer to be used, preferably 100 to 100 50000 poise.

  The modified cross-section fiber excellent in lightness of the present invention is preferably excellent in whiteness and has a chromaticity b * of 5 or less. The chromaticity b * is an index representing the yellowness of the fiber itself, and the smaller the color, the better the whiteness. The chromaticity b * is more preferably 4 or less. As for the lower limit, the chromaticity b * is preferably as small as possible, but if it is −5 or more, there is no particular problem, preferably −4 or more, more preferably −3 or more, and particularly preferably 0 or more. In the modified cross-section fiber excellent in light weight in the present invention, the light reflected on the fiber surface easily enters the inside of the fiber due to the effect of the modified cross-section, and the inclined structure of the void has anisotropy. By reflecting the light of the corresponding wavelength, the fiber has a mild gloss without glare and good whiteness. In addition, since the human optic nerve tends to recognize white objects as light, a material having high whiteness is excellent in visual lightness. Moreover, since the modified cross-section fiber of the present invention can be made really light, it becomes a material that is lighter for humans. In order for the chromaticity b * to be 5 or less, it is preferable not to add as much yellowish color as possible in the fiber. More specifically, it is preferable to use only a very small amount of the polymer A as well as the polymer A, or a very small amount of the polymer B, or not to add a very large amount even if the polymer B is weak. The chromaticity b * was calculated by the method of Example D.

The number of single fibers constituting the multifilament is not particularly limited, and may be set as appropriate according to the purpose of use such as clothing or industrial material. Depending on the application, a monofilament may be used. In the case of multifilaments, it is preferably 2 to 2000, more preferably 4 to 500, taking into account the spinning performance in the spinning or drawing process and the processability in the high-order processing. More preferably, the number is 4 to 250.
The modified cross-section fiber excellent in lightness of the present invention preferably has a fiber residual elongation of 5% to 50%. Here, the fiber residual elongation is a value obtained by measuring the residual elongation of the blend fiber in the present invention by the method of Example E. The fiber residual elongation of 5% to 50% is an optimal residual elongation region having appropriate stretchability in various usage environments for various materials for clothing or industrial use, and has a residual elongation of the region, Moreover, by having the lightness that is the effect of the present invention, it can be used as a wide variety of fiber products. More preferably, the fiber residual elongation is preferably 8% to 40%, and more preferably 10% to 30%.

  The modified cross-section fiber excellent in lightness in the present invention is excellent in lightness. Here, it is defined as having excellent lightness that the apparent specific gravity of the fiber is 90% or less with respect to the specific gravity of the polymer A, for example, 1.242 or less for PET, 1.197 or less for PTT, 1.215 or less for PBT, 1.134 or less for polylactic acid, 1.024 or less for nylon, 0.810 or less for PP, 0.846 or less for PE. Point to. Not only when used as clothing for infants or the elderly, but also when used as vehicle interior materials such as sportswear or outdoor clothing, car seats, etc., the apparent specific gravity of the fiber is small, and it is lightweight with the same bulk (volume) Superiority is a very favorable property. The apparent specific gravity of the fiber is preferably 85% or less, more preferably 80% or less, and even more preferably 75% or less with respect to the specific gravity of the polymer A in that the fiber becomes lighter.

  The fiber strength of the modified cross-section fiber in the present invention is preferably 2.5 cN / dtex or more. When it is used as a sports uniform or outdoor clothing, or when it is used as an industrial material, it should be a strong material. Further, even when the workability of fibers or fiber products is taken into consideration, the yarn physical properties are required to have high fiber strength. The fiber strength is more preferably 3.0 cN / dtex or more, still more preferably 3.5 cN / dtex or more, and particularly preferably 4.0 cN / dtex or more.

  The modified cross-section fiber of the present invention is a matting agent, a flame retardant, a lubricant, an antioxidant, an ultraviolet absorber, an infrared absorber, a crystal nucleating agent, a fluorescent whitening agent, and an end group-blocking as long as the gist of the invention is not impaired. A small amount of an additive such as an agent may be retained.

  The modified cross-section fiber of the present invention is very useful as a fiber itself because it has an excellent natural silk-like luster and touch, and can also have lightness, whiteness, shading, bulkiness and heat retention. Although the fibers can be used as they are, they are sufficiently effective even when used for a part of fiber products, such as mixed fibers with other materials and union knitting. The textile products of the present invention include taffeta, twill, satin, desine, palace, georgette and other woven fabrics, flat knitted fabrics, rubber knitted fabrics, double knitted fabrics, single tricot knitted fabrics, half tricot knitted fabrics, chemical bond methods, thermal bonds, etc. Nonwoven fabrics formed by methods such as a method, a needle punch method, a water jet punch (spun lace) method, a stitch bond method, and a felt method, and ropes and strings. Moreover, there is no restriction | limiting in particular about the form of fibers, such as raw yarn, twisted yarn, and processed yarn. In the case of woven or knitted fabric, it may be subjected to processing such as conventional scouring, dyeing and heat setting, or in the case of non-woven fabric, physical processing such as glazing press, embossing press, compact processing, flexible processing, heat setting, etc. Chemical processing such as mechanical processing, bonding processing, laminating processing, coating processing, antifouling processing, water repellent processing, antistatic processing, flameproof processing, insectproof processing, sanitary processing, foam resin processing, and other micro processing Application processes such as wave application, ultrasonic application, far-infrared application, ultraviolet application, and low-temperature plasma application may be performed, and the final form may be sewn as clothing.

  In combination with other materials, general-purpose synthetic fibers, semi-synthetic fibers, natural fibers, etc., for example, at least one fiber selected from cellulose fibers, wool, silk, stretch fibers, and acetate fibers can be used. Specific examples include cellulose fibers such as natural fibers such as cotton and hemp, steel ammonia rayon, rayon, polynosic, etc., and the mixing ratio of these cellulose fibers is the hygroscopicity, water absorption, In order to make use of antistatic properties and to make use of the natural silk-like luster, touch and lightness of the modified cross-section fiber of the present invention, 25 to 75% is preferable. In addition, the existing wool and silk used in mixed fiber products can be used as they are, and the content of the irregular cross-section fibers mixed with these wool or silk is based on the texture of wool and silk. In order to take advantage of the lightness of the present invention, 25 to 75% is preferable. In addition, the stretch fiber used in the mixed fiber product is not particularly limited. Polyester represented by dry-spun or melt-spun polyurethane fiber, polybutylene terephthalate fiber, and polytetramethylene glycol copolymer polybutylene terephthalate fiber. In the mixed fiber product using stretch fibers, the content of the modified cross-section fiber of the present invention is preferably about 60 to 98%. Moreover, since the expansion-contraction characteristic is suppressed when the content rate of an irregular cross-section fiber exceeds 70%, it can use for an outer, a casual wear use, etc. If it is less than 70%, it can be used for innerwear, foundation, swimwear, etc. due to its stretchability. The acetate fiber used for the mixed fiber product is not particularly limited, and may be a diacetate fiber or a triacetate fiber. Regarding the content of the modified cross-section fibers of the present invention mixed with these acetate fibers, the texture, sharpness, and gloss of the acetate fibers and the natural silk-like luster, touch, and lightness of the modified cross-section fibers are 25. ~ 75% is preferred.

  In these various mixed fiber products, the mixing method is not particularly limited, and examples of the mixing method include woven fabrics such as woven fabrics and reversible fabrics used for warps or wefts, and knitted fabrics such as tricot and Russell. In addition, knitting, tying, and entanglement may be performed.

  The fiber product of the present invention may be dyed, including mixed fiber products, and if necessary, the fiber exhibits a soft texture by scouring and alkali reduction treatment by a conventional method before dyeing. This is preferable. For example, after knitting and weaving, it is preferable to take a process of scouring, pre-setting, dyeing, and final setting by a conventional method. The scouring is preferably performed in a temperature range of 40 to 98 ° C. In particular, in the case of mixed use with stretch fibers, it is more preferable to refine the fiber products while relaxing the fiber products because the elasticity is improved. One or both of the heat sets before and after dyeing can be omitted, but both are preferably performed in order to improve the form stability and dyeability of the textile. The heat setting temperature is 120 to 190 ° C., preferably 140 to 180 ° C., and the heat setting time is 10 seconds to 5 minutes, preferably 20 seconds to 3 minutes.

  A more specific method of the means for producing a modified cross-section fiber excellent in light weight according to the present invention will be exemplified below.

  In the lightweight modified cross-section fiber of the present invention, as a method for forming the modified cross section, for example, the shape of the spinneret hole is a multileaf type such as a trilobal type, a four-leaf type, or a five-leaf type, a triangle, a quadrangle, or a pentagon A polymer A and a polymer B that form a modified cross-section fiber of the present invention from a mouthpiece having a cross-sectional shape capable of forming a modified cross section such as a polygonal shape such as a polygonal shape, a gear shape, a C shape, a Y shape, a T shape, and a star shape A method of obtaining a modified cross-section fiber by discharging a blend composition comprising, or forming a modified cross-section fiber of the present invention using a component that can be eluted using a reagent such as an aqueous solution, hot water, or an organic solvent as a sheath component or a sea component The core composition or island component is a blend composition composed of polymer A and polymer B, and at least after the core-sheath composite fiber or sea-island composite fiber in which the core component or island component forms a deformed cross section, the sheath component is also used. It How to obtain the modified cross-section fibers by eluting the sea components. From the viewpoint of simple process and high productivity, a method of discharging from a die hole having a cross-sectional shape capable of forming a deformed cross-section using a blend composition composed of polymer A and polymer B as a single component is preferable. In order to obtain a fiber with a high profile, it is preferable that the polymer is discharged in a form with a high profile, so that, for example, it has a hole shape that forms a multi-leaf type cross section illustrated in FIGS. When the die is used, it is preferable that the slit length X of the die hole is larger than the slit width Y because the polymer is discharged in a form having a higher degree of irregularity and the degree of irregularity of the resulting fiber is higher. X / Y, which is the ratio of X and Y, is preferably 2 or more, in that the degree of irregularity of the fiber is increased and the fiber exhibits excellent gloss due to a synergistic effect with the inclined structure of the gap. More preferably, it is more preferably 4 or more. If X / Y is too large, the base may become dirty and the pack life may be reduced, leading to a decrease in productivity. Therefore, X / Y is preferably 20 or less, and more preferably 15 or less. Even more preferably, it is 10 or less. When the spun yarn is a multifilament, the shape of the die hole may be the same or different between the single fibers.

    The method for adding the polymer B is not particularly limited. For example, (A) in the usual polymerization reaction of the polymer A, the method of adding at an arbitrary stage before the polymerization reaction of the polymer A stops, (B) A method in which polymer B is added at the time of spinning polymer A, and melt kneading is carried out under normal pressure or reduced pressure using a kneader such as an extruder or static mixer. (C) Polymer B is added at a high concentration in a normal polymer A polymerization reaction. A method in which polymer A to which polymer B has not been added is simultaneously added and diluted by a kneader such as a static mixer or melt mixer under normal pressure or reduced pressure. (D) Polymer B is added to polymer A, and an extruder or static mixer. After melt-kneading at a high concentration under normal pressure or reduced pressure using a kneading machine such as A method in which polymer A to which polymer B has not been added is simultaneously added and diluted by a kneader such as a truder or a static mixer, and is melt-kneaded under normal pressure or reduced pressure. (E) Any stage before discharge in spinning of polymer A In the method, the polymer B melt is discharged from a nozzle-like tube, blended by melt shearing in the polymer flow path, and contained in the polymer A. Preferably, the above-mentioned (B), (C ) Or (D) is employed.

  In melt spinning, the spun yarn discharged from the die hole is cooled below the glass transition temperature of the blend composition of the present invention, and taken up at a take-up speed of 100 to 10,000 m / min. In order to increase the degree of deformation of the fiber, it is preferable to rapidly cool the discharged polymer. For example, when the yarn is cooled using cooling air, the yarn is cooled more rapidly as the temperature of the cooling air is lower and the distance from the cooling air spray start point to the base is shorter. The temperature of the cooling air is preferably 30 ° C. or lower, more preferably 25 ° C. or lower, and even more preferably 20 ° C. or lower in that a fiber having a higher degree of irregularity can be obtained. The lower limit is not particularly limited, but if it is too low, water vapor may freeze in the cooling air flow path and cause clogging. Further, as described above, the yarn is rapidly cooled as the distance between the cooling air spray start point and the base is shorter. The distance between the cooling air spray start point and the die is preferably 20 cm or less, more preferably 10 cm or less, and even more preferably 5 cm or less, in that a fiber having a higher degree of irregularity can be obtained. . When the cooling air is blown from directly below the base as described above, the base surface may be cooled and the temperature of the base surface may be lowered. If the temperature of the die surface is excessively lowered, unmelted polymer is discharged, and as a result, there is a concern that the fibers become non-uniform. Therefore, it is also preferable to use a heater that locally heats the vicinity of the die.

  In order to increase the draw ratio and improve the void forming property in the drawing step, the take-up speed is preferably low, preferably 4000 m / min or less, more preferably 3000 m / min or less, and still more preferably 2000 m / min or less. On the other hand, in order to obtain a fiber having a high degree of profile, it is necessary to increase the cooling efficiency of the discharged yarn as described above. For this reason, the take-up speed is 100 m / min or more, more preferably 500 m / min or more, and further preferably 1000 m / min or more.

  After being taken up, the film is stretched without being wound up or once taken up. The stretching temperature is preferably a glass transition temperature (TgA) of the polymer A + 100 ° C. or less, more preferably a temperature range of TgA−80 ° C. to TgA + 80 ° C., further preferably a temperature range of TgA−80 ° C. to TgA + 20 ° C. It can be done with.

  The draw ratio has a very strong correlation with the void forming property, and the higher the draw ratio, the higher the void ratio. That is, the lightness of the fiber is achieved by high-magnification drawing. The draw ratio may be appropriately changed in order to obtain a desired porosity, but if the draw ratio is too low, the voids themselves are not formed. It is preferable that the film is stretched at a higher magnification because the inclination tendency of the voids is increased and the gloss improvement effect is increased. Furthermore, a skin layer having no voids is simultaneously formed on the fiber surface by the stretching, and the skin layer becomes thinner as the high-magnification stretching achieves a high porosity. For this reason, it is preferable that the residual elongation after stretching is 5 to 50%, and more preferably 8 to 40%. Most preferably, the residual elongation is stretched to 10 to 30%.

  The heating method at the time of stretching is not particularly limited as long as a general-purpose apparatus is used. However, a heating method in which an external force is not applied in a direction other than the fiber stretching direction is preferable in that the degree of irregularity of the fiber can be kept high. It is preferable to employ a heating method using excitation of molecular vibration represented by a pin, a heating plate, an apparatus using a heating liquid or a heating gas, a carbon dioxide laser, or the like.

  Moreover, after extending | stretching, the method of heat-processing at the temperature of Tga + 10 degreeC or more is preferable. The space around the voids developed by heat treatment after stretching is heat-set, and a lightweight fiber with excellent heat resistance is obtained. Here, it is important that the heat treatment performed after stretching is performed at a temperature lower than the melting point of the polymer A so that the developed voids are not crushed.

  The heat treatment method after stretching is not particularly limited as long as a general-purpose apparatus is used. However, the higher the heating efficiency, the more the structure of the fiber is fixed without being relaxed, and a highly durable fiber with voids is obtained. It is preferable to employ a heating technique using excitation of molecular vibration represented by a heating pin, a heating roller, a heating plate, an apparatus using a heating liquid or a heating gas, a carbon dioxide laser, or the like.

  Further, the above-described spun yarn may be false twisted without being stretched or after being stretched. When the drawn yarn is used in false twisting, it is heated by a contact-type or non-contact-type method and false twisted by a disk-like object, a belt-like object, or a pin-like object. When undrawn yarn is used, it is false twisted with a twisted body (disk, pin, belt) while being drawn with or without being heated by a contact or non-contact type heater. The The deformed cross-section fiber that has been false twisted can be wound as it is, but is preferably wound after being heat set again.

  The modified cross-section fiber excellent in lightness of the present invention may have poor compatibility because polymer A and polymer B are incompatible. Therefore, it is preferable to contain a compatibilizing agent. The compatibilizing agent in the present invention is a compound that, when blending polymer B with polymer A, alters the interaction at the interface to enhance the compatibility between the two and finely disperse polymer B. As the compatibilizing agent, a wide variety of compounds such as a low molecular compound or a high molecular compound can be adopted. For example, as the low molecular compound, sodium dodecylbenzenesulfonate, sodium alkylsulfonate, glycerin monostearate, Anionic or cationic surfactants such as tetrabutylphosphonium paraaminobenzenesulfonate and amphoteric surfactants, poly (alkylene oxide) glycols such as polyethylene glycol, methoxypolyethylene glycol, polytetramethylene glycol, and polypropylene glycol, and ethylene oxide / propylene Nonionic surfactants, such as an oxide copolymer, are mentioned.

  Further, as the polymer compound mentioned as the compatibilizer, a polymer compound having high compatibility or affinity for each of the polymer A and the polymer B may be used. For example, a polystyrene polymer or a polyacrylate polymer may be used. , Polymethacrylate polymers, poly (vinyl alcohol-ethylene) copolymers, poly (vinyl alcohol-propylene) copolymers, poly (vinyl alcohol-styrene) copolymers, poly (vinyl acetate-ethylene) copolymers, poly (vinyl acetate-propylene) copolymers , Vinyl-based polymers or copolymers such as poly (vinyl acetate-styrene) copolymers, ionomers, polysaccharides, polyalkylene oxides or poly (alkylenes) that have improved heat resistance and melt plasticity by chemically modifying the side chain moiety. Oxide-ethylene) copolymer, poly (alkylene oxide-propylene) copolymer and other alkylene oxide and vinyl derivative copolymers, or polyalkylene oxide derivatives, alkylene terephthalate and alkylene glycol copolymers, alkylene terephthalate and poly (alkylene oxide) glycols Examples thereof include polymers such as copolymers, copolymers of alkylene terephthalate and polyalkylene diol, and the like. Among them, polystyrene polymer, polyacrylate polymer, polymethacrylate polymer, alkylene terephthalate and alkylene are advantageous in that they have a large effect as a compatibilizing agent and good yarn physical properties when the fiber of the present invention is formed. Preferred are copolymers of glycol, copolymers of alkylene terephthalate and poly (alkylene oxide) glycol, poly (alkylene oxide) glycol, copolymers of alkylene terephthalate and polyalkylene diol, or derivatives of these polymers.

  Specific examples of alkylene terephthalate and polyalkylene diol, a copolymer of alkylene terephthalate and alkylene glycol, a copolymer of alkylene terephthalate and poly (alkylene oxide) glycol, or poly (alkylene oxide) glycol or a derivative thereof, which are considered preferable, are described below. Needless to say, the compatibilizer in the present invention is not limited thereto.

  As a copolymer of alkylene terephthalate and polyalkylene diol, an alkylene terephthalate selected from ethylene terephthalate, propylene terephthalate, butylene terephthalate, pentamethylene terephthalate, hexamethylene terephthalate, etc., and polyalkylene diol selected from polyethylene diol, polybutylene diol, etc. One type of each of alkylene terephthalate and alkylene glycol may be used, or a plurality of types may be used. Specific examples include poly (ethylene terephthalate-polyethylene diol) copolymer, poly (propylene terephthalate-polyethylene diol) copolymer, poly (butylene terephthalate-polybutylene diol) copolymer, and the like. .

  As the copolymer of alkylene terephthalate and alkylene glycol, alkylene terephthalate selected from ethylene terephthalate, propylene terephthalate, butylene terephthalate, pentamethylene terephthalate, hexamethylene terephthalate, ethylene glycol, propylene glycol, butylene glycol (or tetramethylene glycol), penta It is a copolymer comprising an alkylene glycol selected from methylene glycol and hexamethylene glycol, and one or more of each of alkylene terephthalate and alkylene glycol may be used. Specific examples include, but are not limited to, polyethylene terephthalate-butylene glycol copolymer, polypropylene terephthalate-ethylene glycol copolymer, polybutylene terephthalate-tetramethylene glycol copolymer, and the like.

  As the copolymer of alkylene terephthalate and poly (alkylene oxide) glycol, alkylene terephthalate selected from ethylene terephthalate, propylene terephthalate, butylene terephthalate, pentamethylene terephthalate, hexamethylene terephthalate, and the like, diethylene glycol, triethylene glycol, poly (ethylene oxide) glycol, A copolymer comprising poly (alkylene oxide) glycol selected from dipropylene glycol, poly (propylene oxide) glycol, poly (ethylene oxide-propylene oxide) glycol composed of a copolymer of ethylene oxide and propylene oxide, and alkylene terephthalate And 1 each of poly (alkylene oxide) glycol It may be used by classes, or may be used in combination. Although not particularly limited, specifically, polyethylene terephthalate-diethylene glycol copolymer, polyethylene terephthalate-poly (ethylene oxide) glycol copolymer, polybutylene glycol-poly (ethylene oxide) glycol copolymer, polypropylene terephthalate-poly (ethylene oxide) glycol copolymer And so on.

The main chemical structure of poly (alkylene oxide) glycol or its derivative is a group (or group) of aliphatic, aromatic, alicyclic, etc. carbon having a main chain and oxygen atoms bonded alternately. Any poly (alkylene oxide) glycol having a single alkylene oxide as a repeating unit represented by the following general formula (1) can be used.
_{- [(CH 2) a -O} ] m - ··· (1)
Examples of satisfying the formula (1) include poly (ethylene oxide) glycol (a = 2), poly (propylene oxide) glycol (a = 3), poly (tetramethylene oxide) glycol (a = 4), and the like. Of poly (alkylene oxide) glycols.

The poly (alkylene oxide) glycol may be an alternating, random, or block copolymer of different alkylene oxides as represented by the following general formula (2).
_{- {[(CH 2) a} -O] m - [(CH 2) b -O] n} x - ··· (2)
As satisfying the formula (2), for example, a poly (oxyethylene-oxypropylene) copolymer (a = 2 or 3, b = 2 or 3, and a and b may be the same or different. ), Poly (oxytetramethylene-oxyethylene-oxypropylene) copolymer (a = 1 or 2 or 3, b = 1 or 2 or 3, and a and b may be the same or different.) For example, copolymers of different alkylene oxides.

  Further, as the poly (alkylene oxide) glycol, the polyalkylene oxide represented by the above general formula (1) or (2) may be used alone or in a range that does not impair the gist of the invention. You may use what combined the seed | species or more.

  The content of the compatibilizer in the fiber of the present invention is such that the compatibilization is more effectively expressed, and the fiber properties of the obtained fiber are excellent. The content is preferably 0.1% by weight or more, more preferably 1% by weight or more, based on the weight. Further, when added in a large amount, the interfacial affinity between the polymer A and the polymer B becomes too high, and there is a concern that the void forming property is deteriorated. Therefore, the amount is preferably 50% by weight or less, and more preferably 30% by weight. .

  The method of adding the compatibilizer is not particularly limited as long as it is a method of adding to the blend composition of polymer A and polymer B at an arbitrary stage before completion of melt spinning. In a normal polymerization reaction of polymer A, a method of adding and melting and kneading at an arbitrary stage before the polymerization reaction stops, (B) a compatibilizing agent in a blend of polymer A and polymer B prepared in advance Add and melt knead under normal or reduced pressure with a kneader such as extruder or static mixer, (C) Add specified amounts of compatibilizers, polymer A and polymer B to kneader such as extruder and static mixer at the same time during melt spinning And a method of melt-kneading under normal pressure or reduced pressure, and the like. Although not particularly limited, the above-mentioned (B Method or (C) is preferably employed.

EXAMPLES Hereinafter, the present invention will be described specifically and in detail with reference to examples, but the present invention is not limited to the following examples. In addition, the physical-property value in an Example was measured with the following method.

A. Measurement of Intrinsic Viscosity (IV) A sample was dissolved in an orthochlorophenol solution, a relative viscosity ηr at a plurality of points was determined using an Ostwald viscometer at a temperature of 25 ° C., and extrapolated to an infinite dilution.
B. Measurement of critical surface tension In a film made of polymer A or polymer B having a thickness of 50 μm or more, pure water 72.8 dyne / cm, ethyl alcohol (special grade or higher) 22.3 dyne / cm, dioxane 33.6 dyne / cm, benzene 28.9 dyne 20 ° C., humidity 40-80 using all liquids of organic solvents or aqueous solutions having a surface tension of / cm, hexane 18.4 dyne / cm, 20% aqueous ammonia 59.3 dyne / cm, nitrobenzene 43.4 dyne / cm %, The angle between the solid plane in contact with the droplet and the surface of the droplet in contact with the air layer when the droplet rests on a solid under horizontal standing conditions Was measured as the contact angle θ, and cos θ was plotted against the surface tension of the liquid used (Zisman plot), and completely wetted. That is, the critical surface tension γc was obtained by extrapolating the plotted points of the surface tension when cos θ = 1.

C. Measurement of glass transition temperature (Tg) and melting point (Tm) Using a differential scanning calorimeter (DSC-2) manufactured by PerkinElmer, the glass transition temperature (Tg) was measured at a heating rate of 16 ° C./min. Tm and Tg are defined as follows. After observing the endothermic peak temperature (Tm ₁ ) observed once at a rate of temperature increase of 16 ° C./min, hold at the temperature of Tm ₁ + 20 ° C. for 5 minutes and then rapidly cool to room temperature (The quenching time and the room temperature holding time are kept for 5 minutes), and when the measurement is again performed at a temperature rise condition of 16 ° C./min, the endothermic peak temperature observed as a stepwise baseline shift is defined as Tg, The endothermic peak temperature observed as the melting temperature of Tm was defined as Tm.

D. Measurement of chromaticity b * The drawn yarn obtained so that the fineness of the multifilament is 100 dtex is combined or split, and the multifilament is used with a gauge width of 20 / 2.54 cm and a pitch length of 1 mm. A cylindrical knitting was prepared, and b * of the fabric obtained by stacking eight sheets was measured using a color difference meter MINOLTA CR-200 manufactured by Minolta Camera Co., Ltd. In each sample, the measurement results were averaged 3 times for each measurement location and 3 times with different measurement locations, and b * of the sample was averaged.

E. Setting of measurement of fiber strength and residual elongation Using a Tensilon tensile tester (TENSIRON UCT-100) manufactured by Orientec, if it is an undrawn yarn, the initial sample length is 50 mm, the tensile speed is 400 mm / min, and if it is a drawn yarn The fiber strength and the residual elongation were measured at an initial sample length of 200 mm and a tensile speed of 200 mm / min, respectively, and the average values measured five times were used as the measured values.

F. Measurement of Apparent Specific Gravity of Fiber and Polymer and Calculation of Porosity (a) The apparent specific gravity of the fiber is defined in JIS-L-1013: 1999 8.17.1 (published by the Japanese Standards Association, chemical fiber filament yarn testing method). Based on the floating and sinking method, a NaBr aqueous solution is used if the apparent specific gravity of the fiber is 1 or more at a temperature of 20 ° C. ± 0.1 ° C., and the heavy liquid is used if the apparent specific gravity of the fiber is between 1 and 0.789. If the apparent specific gravity of the fiber is between 0.789 and 0.659, a mixed liquid using ethyl alcohol as the heavy liquid and n-hexane as the light liquid. Then, after each fiber was allowed to stand for 30 minutes, the equilibrium state of the float and sink was confirmed, and as described in the above section 8.17.1, the specific gravity value of the mixed liquid that did not float or sink was measured, and five fibers were measured. Average ratio of specific gravity values And the value (Q).
(B) When the apparent specific gravity of the fiber is less than 0.659 100 g ± 10 g D.D. Weighed in advance using the tubular knitted fabric prepared by the method described in 1. In addition, we fixed the weight of which weight and volume were known in advance to the tubular knitted fabric, and added it to ion-exchanged water prepared at 4 ° C ± 1 ° C. After submerging and defoaming with ultrasonic waves for 5 minutes, the volume of the tubular knitting was measured, and the average value of the specific gravity values of 10 fabrics was defined as the measured specific gravity value (Q).
The following formula was used for calculation of the porosity of the fiber.
Porosity (%) = 100 (1-Q / R),
_{R = 100 / (S 1 /} V 1 + S 2 / V 2 + (100-S 1 -S 2) / V p),
However,
S ₁ : addition amount of polymer B (% by weight),
S ₂ : amount of compatibilizer added (% by weight),
V ₁ : density of polymer B (g / cm ³ ),
V ₂ : density of compatibilizer (g / cm ³ ),
V _p : density of polymer A (g / cm ³ )
For the density, the value measured based on the density gradient tube method defined in JIS-L-1013 is used. For example, when the polymer A is polyethylene terephthalate, 1.34 is used for the undrawn yarn, and the drawn yarn is used. 1.38 was used. For example, when the polymer A was nylon 6, 1.130 was used for an undrawn yarn, and 1.138 was used for a drawn yarn.
R: Apparent specific gravity of a modified cross-section fiber excellent in lightness when there is no void G. Calculation of irregularity Blocks with embedded fibers in epoxy resin are subjected to metal dyeing as necessary, and an embedded block is produced in which a single fiber cross section is obtained by cutting in a direction perpendicular to the fiber axis with an ultramicrotome. And a cross-sectional observation at an arbitrary magnification of 1000 to 20000 with an acceleration voltage of 6 kV using a scanning electron microscope (SEM) and an observation device (FE-SEM S-800 manufactured by Hitachi, Ltd.). Digitized photos. In the cross-sectional photograph, the ratio (D1 / D2) of the circumscribed circle diameter D1 and the inscribed circle diameter D2 in the cross section of the single fiber was calculated under the above-mentioned conditions, and the degree of irregularity was calculated.

H. Confirm the incompatibility, average diameter, and discontinuity of polymer B. Metal dyeing is applied to the block in which the fiber is embedded in an epoxy resin, and it is cut in a direction perpendicular to the fiber axis with an ultramicrotome. An ultrathin section having a single fiber cross section is prepared, and traversed at an arbitrary magnification of 5000 to 1000000 times at an acceleration voltage of 75 kV using a transmission electron microscope (TEM) and an observation device (H-7100FA type manufactured by Hitachi, Ltd.). Surface observation was performed and the resulting photographs were digitized. The cross-sectional photograph was image analyzed with WinROOF (version 2.3) manufactured by Mitani Corporation, a computer software, to confirm the incompatibility and discontinuity of polymer B. About incompatibility, the area of all the polymer B which exists on a cross-sectional photograph was calculated, respectively, and it evaluated by the average value of the diameter of the polymer B calculated judging that it was substantially circular from this area value. Furthermore, the discontinuity of polymer B is not necessary when 10 cross-sectional photographs are taken at an arbitrary interval of at least 10,000 times the single fiber diameter, and the average value and distribution of the diameter of polymer B differ depending on the cut surface location. Determined to be continuous. The case of being discontinuous was evaluated as ◯, and the case of being continuous or without polymer B was evaluated as ×.

  I. Confirm the number, diameter, and discontinuity of voids.

A single fiber is placed on the carbon tape affixed to the sample stage, and after platinum deposition (deposition film pressure: 25 to 50 Å, treatment time: about 120 seconds), focused ion beam (FIB) cutting-scanning With a scanning electron microscope (SEM) observation device (STRAIDB235 manufactured by FEI), rough cutting (current: about 7000 pA, processing time: about 20 minutes) and precision cutting (with a Ga focused ion beam accelerated at an acceleration voltage of 30 kV) (Current: about 3000 pA, treatment time: about 4 minutes), and when observing a single fiber cross section in an atmosphere with a degree of vacuum of 1.4 × 10 ⁻¹³ Pa, the sample should be perpendicular to the fiber axis direction. In the case of cutting and observing the single fiber longitudinal section, the sample was cut in parallel to the fiber axis direction with a length of 5 times or more the single fiber diameter. After cutting, using a scanning electron microscope possessed by the apparatus, in an atmosphere with a degree of vacuum of 1.4 × 10 ⁻¹⁹ Pa, with a sample inclination of 52 degrees and an acceleration voltage of 5 kV, the magnification is 80000 times. The single fiber transverse section and the single fiber longitudinal section were observed. At this time, when the whole image of the fiber cross section and the vertical cross section could not be taken at the magnification, partial pictures were taken at the respective positions and pasted using image software to obtain the whole image. First, for the single fiber cross-sectional photograph, computer software WinROOF (version 2.3) manufactured by Mitani Shoji Co., Ltd. was used to calculate the number of voids present in the entire fiber cross-section and the average value of the void diameter by image analysis. . The average value of the diameter of the voids is calculated by calculating the equivalent circle diameter from the area of all the voids existing on each cross-sectional photograph, calculating the equivalent circle diameter, and dividing the sum of the equivalent circle diameters by the total number of voids. By returning, the average value of the diameters was obtained.

  Further, the average diameter d1 of the voids existing in the region encompassed by the circumscribed circle and the inscribed circle of the irregularly shaped fiber and the average diameter d2 of the voids present in the region encompassed by the inscribed circle are calculated by the above-described image analysis method. Then, the value of d2 / d1 was obtained. In addition, when there was no void existing in the area encompassed by the circumscribed circle and the inscribed circle, it was judged as having no inclined structure and indicated as x.

    Since the cross-sectional photograph is a photograph observed at a sample inclination of 52 degrees, the circumscribed circle, the inscribed circle, and the circle with a diameter of D3 are ellipses whose major axis is diameter and minor axis is 0.79 × diameter. It becomes.

  Further, regarding the discontinuity of the voids, the above cross-sectional observation is performed 10 times at an arbitrary interval of 1000 times the diameter or more, the number of voids in each cross-section does not match, and further, the longitudinal cross-sectional observation is discontinuous in the fiber axis direction. When it was confirmed that at least one void was present, it was determined that the void was discontinuous. Evaluation was made as ○ when the gap was discontinuous in the fiber axis direction, and x when the gap was continuous or not.

J. et al. Evaluation of stretchability Regarding the stretchability in the stretching process, when 1 kg of unstretched yarn is stretched, it is evaluated by the number of times that single yarn breakage occurs and the single yarn is wound around the stretching roller. X (impossible) when the yarn is wound, △ (inferior) when the single yarn is wound 10 times or more and 19 times or less, ○ (good) when the number of times the single yarn is wound is 4 times or more and 9 times or less, The number of times the yarn was wound was evaluated as a double circle (excellent) when it was 3 times or less.

K. Evaluation of texture of fiber structure Using the cylindrical knitting produced in (1), sensory evaluation was performed by the method of adding the score to each item with a maximum of 5 points by 10 experts for the following 5 items. Each sample is evaluated from the score of each item (lowest: 0 points, highest: 50 points), xx (bad) for 0-19 points, x (poor) for 20-29 points, 30 In the case of .about.39 points, .DELTA. (Possible), in the case of 40 to 44 points, .largecircle.
Sensory evaluation items
i. Glossy
ii. Lightweight
iii. Touch feeling L. Using identification BIO-RAD Ltd. FT-IR measuring apparatus FTS-40 maleimide structure, the transmitted light intensity is measured, (peak derived from the C-N ^bond) 1184cm -1 around, 1384cm ^-1 (5-membered ring structure When it was confirmed that all of the peaks in the vicinity of 1710 cm ⁻¹ (peaks derived from C═O of maleimide) were observed, it was determined to have a maleimide structure.

M.M. Measurement of Refractive Index Using a chip-like polymer, compression hot press molding was performed at a temperature of melting point + 30 ° C., and immediately water-cooled to obtain an unoriented amorphous film. The refractive index of the film at D line (587.6 nm) at 25 ° C. was measured with an Abbe refractometer.

Comparative Example 1
To a low polymer obtained by ordinary esterification reaction from 166 parts by weight of terephthalic acid and 75 parts by weight of ethylene glycol, 0.03 part by weight of 85% phosphoric acid aqueous solution as a coloring inhibitor and antimony trioxide as a polycondensation catalyst The polycondensation reaction was performed by adding 0.06 parts by weight of cobalt acetate tetrahydrate as a toning agent to obtain a commonly used polyethylene terephthalate having an IV of 0.70. This polyester is used as polymer A, and polymer B as polymethylpentene (TPX, type RT18, hereinafter the same product, hereinafter abbreviated as PMP) manufactured by Mitsui Chemicals, Inc. The hopper is filled with a dry blend that is in a chip state so as to be 8% by weight, and the die hole has the cross-sectional shape shown in FIG. 2 using a twin screw extruder, and the slit length is 0.5 mm. When a melt spinning was performed at a spinning temperature of 290 ° C. using a die having a slit width of 0.08 mm, a hole depth of 0.4 mm, and a hole number of 24, the polymer discharged from the die was cooled with cooling air and 1200 m Was taken at a take-off speed of 1 min / min to obtain a blend deformed cross-section fiber having a trilobal cross section. No yarn breakage occurred during spinning, and the yarn making property was good.

  When the obtained polyester fiber is stretched, the yarn feeding speed of the yarn feeding roller is 100 m / min, and a stretching rate is set using a hot plate at 100 ° C. as a heat source for stretching between the first roller and the second roller. After drawing at 5.0 times and heat-treating the second roller at 150 ° C., the yarn was cooled to below Tg of the polyester with a cold roller and then wound to obtain a modified cross-section fiber excellent in lightness of 50 dtex-24 filaments It was. No thread breakage occurred during drawing, and the drawability was excellent.

The cross-sectional shape of the obtained drawn yarn was a three-leaf type, and the degree of deformity was 1.50. Further, d2 / d1 was 2.3, and an inclined structure of voids was formed inside the fiber. The obtained fiber knitting has a natural silk-like luster, has a good texture such as a touch feeling, a light feeling, and a bulky feeling, and has many fine voids inside the fiber, so that it is lightweight. Excellent fiber. And even if this fiber was bent or worn, its gloss did not change and was a highly durable fiber . The results are shown in Table 1.

Comparative Examples 2-6
In Comparative Example 1, melt spinning and stretching were performed in the same manner as in Example 1 except that the die specifications were changed so as to obtain fibers having different degrees of deformation. No yarn breakage occurred during spinning, and the yarn making property was excellent. During drawing, breakage of the yarn and winding of a single yarn around the roller did not occur, and the drawability was good.

The obtained single fiber cross-sectional shape of the drawn yarn is trilobal type, the modification degree is Comparative Example 2 1.20 Comparative Example 3 1.30 Comparative Example 4 1.40 Comparative Example 5 was 1.80, Comparative Example 6 was 2.00, and Comparative Example 1 was 1.10. As shown in Table 1, by adopting an irregular cross section having a large degree of irregularity in the fiber of the present invention, d2 / d1 is large and the number of voids is increased, resulting in a fiber excellent in glossiness and lightness of the fiber. It was. Further, modification degree as shown in Table 1. In the modified cross-section of less than 1.20, smaller d2 / d1, since even a small number of voids became inferior in luster feeling. The results are shown in Table 1.

Comparative Example 7
Melt spinning and stretching were performed in the same manner as in Comparative Example 1 except that a die capable of forming a flat cross-section fiber was used as the die. No yarn breakage occurred during spinning, and the yarn making property was excellent. During drawing, breakage of the yarn and winding of a single yarn around the roller did not occur, and the drawability was good.

The obtained single-filament cross-sectional shape of the drawn yarn was a flat type with an irregularity of 3.0, and d2 / d1 was 1.5. This fiber had no glare peculiar to flat fibers, had a silky gloss, was excellent in light weight, and was useful as a light shielding material. However, compared with Example 1, it was one step away in terms of gloss, touch, and bulkiness. That is, in the modified cross-section fiber excellent in light weight according to the present invention, the single fiber cross-sectional shape is changed to a multi-leaf type deformed cross section, so that a large inclined structure of d2 / d1 is expressed, and the glossiness, touch feeling, and lightness of the fiber. Also became an excellent fiber . The results are shown in Table 1.

Comparative Example 8
In Comparative Example 1, a normal pressure melter type melt spinning machine was used as the melt spinning machine to be used, and the melt spinning machine was kneaded in the polymer flow path until it was discharged from the spinneret (the mixer was placed in the polymer flow path). Etc. are not disposed), and melt spinning was performed under the same conditions as in Comparative Example 1 and stretching was performed.

The single fiber cross section of the obtained drawn yarn was a three-leaf type cross section, and the deformity was 1.5. The obtained fiber knitting was a fiber having a silky mild luster and a high-class feeling, and was a lightweight fiber. However, all of the glossiness, touch feeling, and lightness of the fiber were all taken over in Example 1. The average diameter of polymer B in this fiber exceeded 1 μm. That is, in the modified cross-section fiber excellent in light weight according to the present invention, by finely dispersing polymer B, the number of voids is large and the fiber has a large inclination tendency, and is excellent in glossiness, touch feeling, and lightness. It was . The results are shown in Table 1.

Example 1
In Comparative Example 1, as a polymer B, a norbornene-based resin arton (grade F5023 specific gravity 1.08 g / cc, critical surface tension of about 31 dyne / cm, Tg 166 ° C., hereinafter abbreviated as arton) manufactured by JSR Corporation is obtained. Add 50% by weight with respect to the total fiber weight, adjust the discharge rate, and make the draw ratio 5.3 times, melt spinning and drawing in the same manner as in Example 1 to obtain 50 dtex-24 filaments. A drawn yarn was obtained. No thread breakage occurred during stretching, and the stretchability was very good.

The fiber cross section of the obtained drawn yarn was recognizable as a three-leaf type, and the degree of irregularity was 1.5. The obtained fiber tubular knitting is a silky mild glossy and very high-quality fiber, and was excellent in textures such as dry feeling, creaking, sharpness, and bulkiness. Moreover, d2 / d1 was 3.5, and it had an inclined structure of highly developed voids inside the fiber. Thus, by adopting a polymer having a Tg higher than that of polymer A as polymer B in the present invention, an inclined structure having a large d2 / d1 can be formed, resulting in a fiber having a better gloss feeling. At the same time, it also has excellent lightness. Even if the fiber was bent or worn, the gloss did not change, and the fiber was highly durable . The results are shown in Table 1.
Example 2
In Example 1 , as a polymer B, a polystyrene resin stylon (grade 8259 specific gravity 1.05 g / cc, critical surface tension about 39 dyne / cm, Tg 100 ° C., hereinafter abbreviated as PS) was used as a comparative example. In the same manner as in No. 7, melt spinning and drawing were performed to obtain a drawn yarn of 50 dtex-24 filament. No thread breakage occurred during stretching, and the stretchability was good.

The fiber cross section of the obtained drawn yarn was recognizable as a three-leaf type, and the degree of irregularity was 1.5. The obtained tubular knitting of the fiber had a silky luster and was a high-quality fiber. However, when compared with Example 9, the gloss was somewhat strong, and Example 9 was slightly inferior to Example 9 in terms of gloss. d2 / d1 was 2.0, and had an inclined structure of highly developed voids inside the fiber. As described above, in the present invention, the polymer B has a higher Tg, so that a slanted structure with a large d2 / d1 can be formed, and the use of a polymer with a low refractive index results in a fiber having a higher gloss. It was. Even if this fiber was bent or worn, its gloss did not change, and it was a highly durable fiber . The results are shown in Table 1.

Examples 3 and 4, Comparative Examples 9 and 10
In Example 1 , melt spinning was performed in the same manner as in Example 1 except that the content of Arton was changed variously and the discharge amount was adjusted using a die forming a five-leaf type cross section. Drawing was performed to obtain a drawn yarn of 50 dtex-24 filament.

As is apparent from Table 1 , Examples 3 and 4 were superior to Comparative Examples 9 and 10 in terms of fiber gloss, touch and lightness. Compared with Comparative Examples 9 and 10 , Examples 3 and 4 were fibers having a large number of voids and a large d2 / d1. That is, by adjusting the content of the polymer B to an appropriate amount, the drawn yarn obtained was more excellent in glossiness, touch feeling, and lightness.

  Not only has a gloss and touch that is very close to natural silk, but also has lightness, bulkiness, whiteness, light-shielding properties, and heat-retaining properties, as well as excellent durability of fine voids. Because it has tension and waist, it is especially formal clothing such as suits and dresses, lining, underwear, swimwear, sports clothing (golf wear, gateball, baseball, tennis, soccer, table tennis, volleyball, basketball, rugby, American football, hockey, Suitable for apparel such as athletics, triathlon, speed skating, ice hockey, etc.), outdoor clothing (shoes, bags, supporters, socks, mountaineering), uniform clothing such as white clothing, handkerchiefs, scarves, ties For decorative products such as various vehicle interior materials, industrial products such as carpets and curtains Also preferably used.

It is explanatory drawing which shows the method of calculating the irregularity degree in this invention. It is explanatory drawing which shows an example of a nozzle | cap | die hole shape which can obtain the irregular cross-section fiber (three-leaf type cross section) in this invention. It is explanatory drawing which shows an example of a nozzle | cap | die hole shape which can obtain the irregular cross-section fiber (5-leaf type cross section) in this invention. It is explanatory drawing which shows an example of a nozzle | cap | die hole shape which can obtain the irregular cross-section fiber (8-leaf type cross section) in this invention.

Explanation of symbols

1: circumscribed circle 2: inscribed circle 3: area included between circumscribed circles 4: inscribed area inside inscribed circle D1: diameter of circumscribed circle D2: diameter of inscribed circle X: Slit length Y: Slit width

Claims (10)

Two components of polymer A and polymer B that are incompatible with each other are blended, and in the fiber cross section perpendicular to the fiber axis direction, polymer A is a sea and polymer B is an island-forming fiber, The content of B is 1% by weight or more and 15% by weight or less with respect to the total weight of the fiber, and the relationship between the glass transition temperature TgA of the polymer A and the glass transition temperature TgB of the polymer B is TgB−TgA ≧ 5 ° C. The cross section of the fiber has a deformed cross section with a degree of deformity of 1.20 or more, has a large number of fine voids discontinuous in the fiber axial direction inside the fiber, and in the cross section of the fiber, between the circumscribed circle and the inscribed circle A modified cross-section fiber excellent in light weight, characterized in that the average diameter d1 of the included fine voids and the average diameter d2 of the fine voids contained inside the inscribed circle satisfy the following formula:
d2 / d1 ≧ 1.30
Apparent specific gravity of fiber ≦ specific gravity of polymer A × 0.9 2. The modified cross-section fiber excellent in light weight according to claim 1, wherein there are 300 or more fine voids present in the cross section of the fiber. 3. The modified cross-section fiber excellent in light weight according to claim 1, wherein the chromaticity b * value of the fiber is 5 or less. 4. The modified cross-section fiber excellent in lightness according to any one of claims 1 to 3, wherein the refractive index of the polymer B is 1.55 or less. The modified cross-section fiber excellent in lightness according to any one of claims 1 to 4, wherein the polymer B is a polyolefin-based polymer having a cyclic structure. 6. The modified cross-section fiber excellent in light weight according to any one of claims 1 to 5, wherein the polymer A is a polymer selected from a polyester-based polymer, a polyamide-based polymer, and a polyolefin-based polymer. 7. The modified cross-section with excellent light weight according to claim 6, wherein the main repeating unit of polymer A is a polyester comprising at least one repeating unit selected from ethylene terephthalate, butylene terephthalate, propylene terephthalate and lactic acid. fiber. 8. The light weight variant according to claim 1, wherein the relationship between the critical surface tension γcA of polymer A and the critical surface tension γcB of polymer B is γcA−γcB ≧ 5 dyne / cm. Cross-section fiber. The modified cross-section fiber excellent in lightness according to any one of claims 1 to 8, wherein the fiber strength is 2.5 cN / dtex or more. A fiber product having silky luster, characterized in that the modified cross-section fiber excellent in lightness according to any one of claims 1 to 9 is used in part or in whole.

Images