JP2007169813A - Fiber for rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber for rubber compositions, which is suitably usable for tires excellent in lightness and steering stability, vulcanized rubber suitably usable for treads and the like of the tires, and a material suitably usable for the vulcanized rubbers and the like. <P>SOLUTION: The fiber for rubber compositions which has a length of 0.05-30 mm, comprises a polymer A having fiber-forming ability and a polymer B incompatible with the A and has ≥100 cavities in a cross-section orthogonal to the fiber axis direction, wherein the cavities do not communicate in the fiber axis direction and the fiber has a skin layer with no cavity on the fiber surface layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fiber for a rubber composition. More specifically, among the applications of the rubber composition, particularly when it is blended in a tire excellent in lightness and steering stability, particularly in a tread of the tire, it suitably contributes to improvement in fuel efficiency and steering stability. The present invention relates to a fiber for a rubber composition.

  Tires are indispensable in so-called automobiles such as wheelbarrows, bicycles, motorcycles, private cars, trucks, cultivators, military vehicles, space development vehicles, marine development vehicles, and the like. Conventionally, this tire is, for example, a so-called run-flat tire that can run stably even when the tire is out of air, a tire that has been reduced in weight for low fuel consumption performance, and a frictional force on a snowy and ice road surface. A variety of functions have been studied depending on the purpose, such as improved ones, improved handling stability, and comfortable rides.

  For example, as a technique for imparting a function to enable stable running while maintaining cushioning properties even when the tire is out of air, a technique of filling a hollow fiber in the tire is disclosed (Patent Document 1). Or see 2). This technique is intended to retain the cushioning property of the tire by filling the annular hollow portion of the tire with hollow fibers, and does not impart lightness to the tire. In addition, with respect to its original cushioning properties, the amount of hollow portions that can be formed inside the fibers of the hollow fibers is limited, and the cushioning effect is not sufficiently exhibited, and the hollow portions of the hollow fibers are crushed. It was easy to end up, and once it was crushed, it did not recover and its cushioning properties deteriorated over time.

  In addition, there is a demand for improvement in low fuel consumption performance of vehicles due to environmental problems regarding energy, and a technology for reducing rolling friction or imparting light weight to tires is disclosed in order to meet such demands (see Patent Document 3). The technology is intended to reduce the weight by forming a hollow portion on a tire bead apex or filling a lightweight filler, and although it can certainly give light weight, it is difficult to form a stable hollow portion and is lightweight. In addition, there is a difficulty in imparting the property, and the strength of the bead apex portion is also relatively inferior, so that the steering stability performance is lowered.

  On the other hand, a technique for improving drivability or braking performance by improving frictional force on an icy and snowy road surface has been disclosed (see Patent Document 4, Patent Document 5, or Patent Document 6). In these technologies, first, a tread rubber containing a one-hole type hollow fiber is provided with block rigidity, and in the technology using the hollow fiber sucking up water on the road surface, the hollow fiber used in the technology is used. Since it is a single-hole type that does not have its own characteristics, when it is crushed by an impact or the like, its hollow fiber does not recover again, and as a result, the block rigidity gradually deteriorates over time. It was. Also, the hollow fiber and the foaming agent coexist in the rubber to melt the hollow fiber at the time of vulcanization, and at the same time, the foaming agent is foamed so that the gas derived from the foaming agent is present in the hollow portion of the hollow fiber trace. As for the technology for forming the part, the rigidity of the hollow fiber itself is not utilized, and the hollow fiber melts at a temperature not higher than the vulcanization temperature, and is simply a “template” itself for forming the hollow part. However, the hollow part is not formed stably, and the hollow part is large because it depends on the outer shape of the fiber, and the ability to suck up water on the road surface is low, and as a result, the performance on ice can be expected to improve much. It was not.

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 lightweight property whose fiber has an apparent specific gravity of 1.2 or less is proposed (see Patent Document 7). This technique exhibits excellent lightness due to the presence of a large number of fine voids inside the fiber, and can obtain a lightweight fiber suitable for clothing and industrial applications. However, when the technology was proposed, it was not found that the obtained tire had an excellent function when it was included in a specific use derived from the fiber structure, that is, a tire rubber composition. However, there was no prediction or suggestion about a suitable fiber structure for the tire to have better rigidity and steering stability.
Japanese Patent Laid-Open No. 51-113903 (Claims) JP-A-1-132403 (Claims) JP-A-6-286427 (Claims, paragraph [0002]) JP-A-4-110212 (Claims) JP-A-11-60771 (Claims) JP 2001-2832 A (Claims) JP 2004-183196 A (Claims)

  An object of the present invention is to solve the above-mentioned problems of the prior art and to use a vulcanized rubber used for a tire excellent in light weight and steering stability, or in a structure part that requires slip suppression on an unstable road surface such as on ice or snow. It is providing the fiber for adding to a rubber composition suitable as raw materials.

  The present invention relates to a fiber for a rubber composition that is suitably used as a raw material for tires and vulcanized rubbers having excellent lightness and handling stability. It has been found that the drawbacks of the prior art can be eliminated by using the composition and that further advantages can be imparted, and the present invention has been achieved.

  That is, the present invention comprises a polymer A having fiber-forming ability and a polymer B incompatible with A, having 100 or more hollow portions in a fiber cross section perpendicular to the fiber axis direction, and Provided is a fiber for a rubber composition having a fiber length of 0.05 to 30 mm, in which a hollow part is not communicated in the fiber axis direction, and a fiber layer has a skin layer having no hollow part.

  With the rubber composition using the fiber of the present invention, the above conventional problems can be solved. In other words, it has excellent lightness for improving the fuel efficiency of vehicles derived from environmental problems such as energy saving, and has powerful and excellent water film removal capabilities derived from countless hollow parts for running on snowy and snowy road surfaces. Therefore, the operational stability on the snowy and snowy road surface is extremely excellent, and in addition to these performances, there are innumerable hollow portions of the lightweight fibers used, and all the stresses can be dispersed and eliminated. In addition, it is possible to manufacture an unprecedented high-performance tire in which the hollow portion is held without being crushed, and as a result, these performances can be permanently provided. Also, other than tires, rubber compositions suitable for these, such as vulcanized rubber suitable for structures that require slip suppression on unstable road surfaces such as icy and snowy road surfaces, can be produced.

  The fiber referred to in the present invention refers to a fiber having an elongated shape and a ratio of a length to an apparent diameter of at least 10. In the present invention, it is necessary to have a length of 30 mm or less in view of having good dispersibility in the rubber composition, particularly among short fibers (staples) produced by the production of conventional synthetic fibers. . Moreover, about a lower limit, it is 0.05 mm or more as a cut length which can be manufactured practically. And it is more preferable that it is 0.05-20 mm in length, it is especially preferable that it is 0.1-10 mm in length, and it is most preferable that it is 0.2-5 mm in length. Further, the fiber diameter of the fiber is not particularly limited, but the fiber cross section perpendicular to the fiber axis direction (to be described later) (hereinafter, the fiber cross section perpendicular to the fiber axis direction is simply referred to as “fiber cross section”). The fiber diameter is 1000 μm or less in that the number of the hollow parts or the average diameter of the hollow parts becomes a more preferable size, or that the rubber composition has good dispersibility as described above. More preferably, it is 200 micrometers or less, and it is especially preferable that it is 50 micrometers or less. In addition, the lower the fiber diameter, the better the dispersibility when it is contained in the rubber composition, and the frictional force when it becomes a tire is improved, which is preferable because the operation stability is excellent. The thickness is preferably 0.1 μm or more, and more preferably 0.5 μm or more in that stable light weight can be maintained.

  The fiber for rubber composition of the present invention has 100 or more hollow portions in a fiber cross section perpendicular to the fiber axis direction, and the hollow portions do not communicate in the fiber axis direction and exist discontinuously. The hollow part in this invention makes a thing 20 nm or more in diameter a hollow part. When the fibers are used in the present invention, by having 100 or more hollow portions, the hollow portions disperse stress and are very difficult to be crushed, and the above-described lightness or operational stability can be maintained permanently. . The number of the hollow portions is preferably as large as possible because stress can be dispersed, and is preferably 300 to 50,000 in view of the number that can be actually formed. Furthermore, the number of the hollow portions is particularly preferably 500 to 20,000 from the viewpoint of imparting better operational stability. The number of the hollow portions is C.C. Defined as the average number of hollows measured in the term.

  Moreover, about the magnitude | size of this hollow part, it is preferable that the average diameter of the hollow part in a fiber cross section is a magnitude | size of 1/10 or less with respect to the fiber diameter of a fiber cross section, and is 1/20 or less. More preferably. In addition, the smaller the average diameter of the hollow part, the more difficult the hollow part to be crushed, which is preferable in terms of maintaining the fiber shape. On the other hand, the tire formed from the rubber composition using the fiber of the present invention is stable on an icy and snowy road surface. Since it is desirable to have a certain size in terms of excellent properties, the lower limit is preferably 1/5000 or more and 1/2000 or more with respect to the fiber diameter of the fiber cross section. More preferred. And in terms of use for rubber compositions, the average diameter is within this range, so that the fiber itself, and hence the weight when forming a tire, is excellent in lightness as well as being able to disperse the stress applied to the fiber. Therefore, the hollow portion is hardly crushed. The average diameter of the hollow portion is C.C. Measured by the term.

  The hollow part of the fiber of the present invention is not continuous in the fiber axis direction and is discontinuous. By having the hollow portion, as described above, the tire made of the rubber composition containing the fiber of the present invention is extremely lightweight. Further, since the hollow portion is discontinuous, an external force can be dispersed and the hollow portion can be hardly crushed. The reason why the hollow portion is discontinuous in the fiber axis direction or the details of the generation mechanism are unknown. However, the discontinuity is probably due to the relationship between the polymer A and the polymer B forming the lightweight fiber, which will be described later. (1) Blend of polymer A and polymer B incompatible with A (2) The polymer B does not follow the deformation of the polymer A at the time of spinning or stretching, and arbitrarily splits and spreads. (3) The starting point is the interface between the polymer A and the polymer B. As the polymer A itself or the composite of the polymer A and the polymer B is torn, these phenomena such as peeling and splitting are expressed rather than alone, and discontinuous toward the fiber axis direction by a synergistic effect. It is assumed that a hollow part is generated. Furthermore, since the generation of the hollow portion is randomly expressed in the fiber, the hollow portion is discontinuous in the fiber axis direction as a result. The discontinuity of the hollow portion in the fiber axis direction is described later in C.I. It is confirmed by the paragraph.

The hollow portion of the fiber of the present invention is a figure in which the fiber cross-sectional shape satisfies the following condition (1) when the center of gravity of the fiber cross-section exists in the fiber in the fiber cross-section perpendicular to the fiber axis direction. When the outer layer portion and the inner layer portion are divided by the above, it is preferable that the average diameter d1 of the hollow portion existing in the inner layer portion is larger than the average diameter d2 of the hollow portion existing in the outer layer portion.
(1) The figure similar to the fiber cross-sectional shape shares the fiber cross-sectional shape and the figure centroid, and the distance r from the figure centroid to the figure outer side of the figure is the distance from the center of gravity to the outer side of the fiber cross-section. 1/2 of R.
When the outer layer portion and the inner layer portion are divided according to the figure satisfying the condition (1), the average diameter d1 of the hollow portion existing in the inner layer portion is larger than the average diameter d2 of the hollow portion existing in the outer layer portion. Relates to the size (diameter) of the hollow portion in the fiber cross section perpendicular to the fiber axis direction, the diameter of the hollow portion gradually increases from the fiber outer layer portion toward the inner layer portion, that is, the hollow portion in the fiber cross section Means that it has an inclined structure, which makes it difficult to collapse the hollow portion of the fiber. Thereby, regarding the lightness of the tire formed from the rubber composition containing the fiber of the present invention, the hollow portion of the fiber is not easily crushed, and the lightness of the tire is further enhanced.
In general, if the fiber cross-sectional shape is a round cross-section, for example, (1) can be applied because the center of gravity of the fiber cross-section is present in the fiber, and the fiber structure is not easily crushed. However, when the fiber cross-sectional shape has a space portion that is not the fiber itself, such as C-shaped fiber cross-sectional shape, for example, the fiber cross-section, the cross-section of the fiber is not able to disperse the stress, In addition, an inclined structure in the fiber cross section of the hollow portion is not easily generated. Furthermore, (1) cannot be applied, and as a result it is difficult to define. That is, in the fiber of the present invention, although it is possible to apply a modified cross-section fiber as described later, a cross-sectional shape having a space portion where the center of gravity of the fiber cross-sectional shape is not the fiber itself is not preferable.

  When the diameter ratio d1 / d2 between the average diameter d1 of the hollow portion existing in the inner layer portion and the average diameter d2 of the hollow portion existing in the outer layer portion is 1.01 or more, the arrangement of the hollow portion is the fiber inner layer. Although it is recognized that the fiber outer layer portion has an inclined structure from the portion, it is preferable that the d1 / d2 is larger because the hollow portion of the fiber is less likely to be crushed, and the value is d2 / d1 ≧ 1.30. More preferably, d2 / d1 ≧ 1.5 is more preferable, and d2 / d1 ≧ 1.8 is particularly preferable. On the other hand, the upper limit of d2 / d1 is not particularly limited, but is preferably 10.0 or less. For example, in the schematic diagram of the fiber shown in FIG. 4, the outer layer portion is indicated by (a) and the inner layer portion is indicated by (b). The inclined structure of the hollow portion is described later in C.I. It is confirmed by the paragraph.

  The fiber of the present invention has a fiber cross-sectional shape perpendicular to the fiber axis direction. In the rubber composition, the fiber cross-sectional shape perpendicular to the fiber axis direction is circular or elliptical in terms of further improving the adhesion to the rubber. It may be a substantially circular shape, or a minus-shaped cross section generally called a flat type. When the cross-sectional shape is a negative flat cross section, it is recognized that the ellipse is further extended, but it is very preferable in terms of adhesion to rubber. FIG. 2 shows an example of the-type cross-sectional structure. When the width (d) and length (L) of the cross section are defined as shown in FIG. 2, the ratio L / d is 1.2. The above is preferable. The L / d is preferably as large as possible, but it is possible to achieve approximately 10 or less in view of the fiber-forming property of the fiber. In the case of the -shaped irregular cross-section fiber, the inclined structure of the hollow portion, which is said to be difficult to be crushed, is easily developed, and the weight is reduced when a tire made of a rubber composition containing the fiber of the present invention is formed. It is very preferable because of its preservability.

  On the other hand, as will be described later, the fiber of the present invention has a deformed cross section whose fiber cross section perpendicular to the fiber axis direction has a deformity of 1.2 or more in order to further reduce the weight of the rubber composition. Preferably there is. Although the calculation method of the irregularity will be described later, in addition to the lightness due to the hollow portion of the fiber itself when the irregularity is 1.2 or more, when the rubber composition is formed, rubber is formed on the outer peripheral portion of the fiber. When a tire is formed from a rubber composition using the fiber of the present invention, a space that is difficult to invade appears, which is preferable because the weight is further increased. As a secondary action, when the single fibers are in contact with each other and the distance between the single fibers is small, a space is effectively expressed between the single fibers, which also contributes to an improvement in weight when it becomes a tire. preferable. Also, with respect to the inclined structure of the hollow portion described above, the greater the value of the deformity is, the more synergistic improvement in lightness is seen. Therefore, the deformity is preferably 1.3 or more, preferably 1.4 or more More preferably, it is more preferably 1.5 or more. Although it does not restrict | limit in particular about an upper limit, It is preferable that it is 7.0 or less in view of the retainability of the deformity degree in the manufacture stage of a fiber, It is more preferable that it is 5.0 or less, It is 3.0 or less Is even more preferred, with 2.0 or less being particularly preferred.

  The aforementioned degree of irregularity 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 fiber cross section perpendicular to the fiber axis direction. 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 determined 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 fiber outline in the single fiber cross section, and the circumscribed circle is the single fiber cross section. Is a circle circumscribing the curve that outlines the fiber. For example, the degree of irregularity in the case 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 outline of the 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 tangent circle does not intersect with the curve that forms the outline of the fiber is defined as an inscribed circle. A circumcircle is a circle that circumscribes at least two points in the curve that shows the outline of the fiber, exists only outside the cross section of the single fiber, and has the smallest radius that can be taken within the range where the circumference of the circumcircle does not intersect the outline of the fiber Is a circumscribed circle.

  The cross-sectional shape when the fiber of the present invention has an irregular cross section is not particularly limited, and can take a wide variety of cross-sectional shapes. For example, shapes such as a polygonal shape, a gear shape, a petal shape, a multileaf shape, a star shape, a + shape, and the like can be given as general names. From the viewpoint of easily forming a space in the outer periphery of the fiber, a multi-leaf type, a polygon type, a gear type and a star shape are preferable, a + type and a multi-leaf type are more preferable, and a multi-leaf type is particularly preferable. . A multileaf type cross section refers to a cross section having irregularities and the same number of concave portions and convex portions, and the multileaf type fiber formed continuously in the fiber longitudinal direction has rubber on the fiber outer peripheral portion. It is easy to form a space that is difficult to enter. Moreover, since it is easy to form a space even when single fibers are close to each other, it is preferable because a lightweight property is more exhibited when a tire made of a rubber composition using the fiber of the present invention is formed. In addition, when the fiber of the present invention has a multi-leaf type cross section, the upper limit and the lower limit of the number of leaves are not particularly limited, but it holds a lot of space and the fiber itself has good rigidity and lightness. In that respect, it is preferably 3 or more. On the other hand, in view of the fiber-spinning properties 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 deformed section of 8 or less leaves, and a multi-leaf type deformed section of 6 or less leaves More preferably, it is a cross section.

  The fiber for rubber composition of the present invention needs to have a skin layer having no hollow part on the fiber surface. The skin layer in the present invention refers to the side closest to the fiber surface of the hollow part, the side closest to the fiber surface, and the fiber surface with respect to the hollow part closest to the fiber surface layer, which is recognized as a hollow part having a diameter of 20 nm or more The distance from is the skin layer in the present invention. When the fiber of the present invention has a skin layer to form a rubber composition contained in the rubber, the fiber surface is not deteriorated or reduced due to bending or abrasion, and moreover, it is present inside the fiber. Since the durability against crushing of the hollow portion is high, it is excellent in lightness. Further, when a rubber composition is used as a tire, grip characteristics are improved and steering stability is excellent. However, if the thickness of the skin layer is too thick, the volume in which the hollow portion is formed inside the fiber decreases, and as a result, the fiber tends to be inferior in lightness. Therefore, the thickness of the skin layer is a fiber perpendicular to the fiber axis. When the cross-sectional shape is a circle or an ellipse such as an ellipse, it is preferably 1/8 or less of the fiber diameter, preferably 1/10 or less, and more preferably 1/15 or less. Alternatively, when the fiber cross section perpendicular to the fiber axis direction is an irregular cross section, the thickness of the skin layer is preferably 1/5 or less of the diameter D1 of the circumscribed circle, and more preferably 1/10 or less. Preferably, it is more preferably 1/15 or less. Further, if the thickness is too thin, the effect as a skin layer tends to be lost, which is not preferable. Therefore, when the shape of the above-described fiber cross section is a circle or an ellipse or the like, it is necessary to be 1/500 or more of the fiber diameter. , More preferably 1/200 or more, and particularly preferably 1/100 or more. Or when the fiber cross section perpendicular | vertical to a fiber axial direction is an irregular cross section, the thickness of this skin layer needs to be 1/500 or more of D1, It is preferable that it is 1/200 or more, 1/100 The above is particularly preferable. This skin layer is composed of a blend of polymer A and polymer B, which is naturally produced without forming a void layer in the outer layer portion of the fiber in the manufacturing method in which the hollow portion described later is formed. Alternatively, as described later, other components that are not blends of the polymer A and the polymer B may be arranged as a sheath component to form a skin layer by a composite spinning method. Here, the component of the skin layer formed by being arranged as a sheath component by the composite spinning method may contain at least one of polymer A or polymer B, or both polymer A and polymer Other components completely different from B may be used.

  In addition, the hollow ratio indicating the volume ratio of the hollow portion of the fiber affects the lightness of the tire made of the rubber composition of the present invention. The higher the hollow ratio, the better the tire is. It is preferable. The hollow ratio is preferably 10 to 65%, and more preferably 15 to 60% in view of yarn production. In addition, the hollow ratio of the hollow portion is the C.C. Measured by term and defined as mean value.

  The fiber of the present invention contains polymer A having fiber forming ability as a main component. A wide variety of polymers A having fiber-forming ability can be exemplified, but as a preferable one, for example, a monomer having a vinyl group is added by an addition polymerization reaction such as radical polymerization, anionic polymerization, or cationic polymerization. Examples thereof include polyolefin-based polymers synthesized by the mechanism of polymer generation and other vinyl-based polymers. More specifically, polyethylene, polypropylene, polybutylene, polymethylpentene, polystyrene, polyacrylic acid, polymethacrylic acid, polymethyl methacrylate, polyacrylonitrile, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene chloride, and vinylidene polycyanide. These are, for example, polyethylene alone or polymers obtained by homopolymerization such as polypropylene alone, or copolymer polymers formed by carrying out a polymerization reaction in the presence of a plurality of monomers. For example, when polymerization is performed in the presence of styrene and methyl methacrylate, a copolymerized polymer called poly (styrene-methacrylate) is produced. However, such a copolymer may be used as long as the gist of the invention is not impaired. A certain point It may be between. Among these polyolefin-based polymers, polyethylene, polypropylene, polybutylene, and polymethylpentene are more preferable as those that can impart light weight that is preferable when the tire of the present invention is used in a rubber composition.

  As the polymer A having fiber forming ability, for example, a polyamide polymer formed by a reaction of carboxylic acid or carboxylic acid chloride and an amine can be mentioned as a preferable one. Specifically, nylon 6 and nylon 7 can be mentioned. 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 the gist of the present invention Other aromatic, aliphatic, and alicyclic dicarboxylic acids and aromatic, aliphatic, and alicyclic diamine components, or one compound such as aromatic, aliphatic, and alicyclic, and carboxylic acid, as long as they are not damaged A polyamide in which an aminocarboxylic acid compound having both amino groups may be used alone, or the third and fourth copolymerization components are copolymerized A polymer may be. Of these polyamide-based polymers, nylon 6 or nylon 6,6 is more preferable because it can impart superior lightness in the present invention or has an affinity for rubber.

  Examples of the polymer A having fiber-forming ability include a polyester polymer formed by an esterification reaction of a carboxylic acid and an alcohol. The polyester polymer is particularly preferable as the polymer A used in the present invention because it is excellent in various functions as a resin in a well-balanced manner. Specifically, examples of the polyester-based polymer used in the present invention include a polymer formed from an ester bond of a dicarboxylic acid compound and a diol compound. Examples of such a polymer include polyethylene terephthalate and polypropylene terephthalate. (Also referred to as polytrimethylene terephthalate), polybutylene terephthalate (also referred to as polytetramethylene terephthalate), polyethylene naphthalate and polycyclohexanedimethanol terephthalate, or a liquid crystalline polyester having a molten liquid crystallinity mainly composed of an aromatic hydroxycarboxylic acid Is mentioned.

  The polyester polymer used as the polymer A and formed from an ester bond of a dicarboxylic acid compound and a diol compound may be copolymerized with other components within a range not impairing the gist of the present invention. As a polymerization component, for example, as a dicarboxylic acid compound, 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, And aromatic, aliphatic, alicyclic dicarboxylic acids and their alkyl, alkoxy, allyl, aryl, amino, imino, halide and other derivatives, adducts, structural isomers, and optical isomers. Among these dicarboxylic 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 copolymer component may be a polyfunctional molecule having three or more ester-forming functional groups in one molecule in one compound. Examples of the ester-forming functional group include a hydroxyl group, a carboxyl group, Any functional group of an ester bond formed by condensation of a hydroxyl group and a carboxyl group may be used. Examples of the polyfunctional molecule include pentaerythritol, pyromellitic acid, trimethylolpropane, trimellitic acid, and dimethylol. Propionic acid, dipentaerythritol, glycerol, sorbitol, trimethylolethane, trimethylolbutane, 1,3,5-trimethylolbenzene, 1,2,6-hexanetriol, 2,2,6,6-tetramethylolcyclohexanol , Hemimetic acid, trimesic acid, prenitic acid, merophanic acid 5-hydroxyisophthalic acid, 2,5-dihydroxyisophthalic acid, 2,5-dihydroxyterephthalic acid, and the like, and ester compounds thereof, such as alkyl, alkoxy, allyl, aryl, amino, imino, halide, etc. Derivatives, adducts, structural isomers, and optical isomers may be used, and one of these polyfunctional molecules may be used alone, or two or more of them may be combined in a range that does not impair the gist of the invention. May be used. When these polyfunctional molecules are copolymerized, it is preferable because the number of hollow portions is larger or smaller and densely formed.

  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. Although not limited, for example, polymers related to these include polylactic acid, poly (3-hydroxypropionate), poly (3-hydroxybutyrate), poly (3-hydroxybutyrate valerate), In addition, poly (hydroxycarboxylic acid) such as aromatic, aliphatic, alicyclic dicarboxylic acid, or aromatic can be used as long as they do not impair the gist of the present invention. Aliphatic, aliphatic, and alicyclic diol components may be used, or multiple types of hydroxycarboxylic acids may be copolymerized. And it may be.

  Of these polyester polymers that are preferred, polyesters whose main repeating unit is ethylene terephthalate, propylene terephthalate, butylene terephthalate, or lactic acid are more preferred, and polyesters whose main repeating unit is ethylene terephthalate are particularly lightweight. Easy and most preferred.

  In addition, the polymer A having fiber-forming ability used in the present invention is formed by cyclization polycondensation of a polycarbonate polymer formed by transesterification of an alcohol and a carbonic acid derivative, a carboxylic acid anhydride and a diamine. Polyimide polymers, polybenzimidazole polymers formed by the reaction of dicarboxylic acid esters and diamines, polysulfone polymers, polyether polymers, polyphenylene sulfide polymers, polyether ether ketone polymers, polyether ketone ketones In addition to polymers such as polymers and aliphatic polyketones, cellulose polymers and polymers derived from natural polymers such as chitin, chitosan and derivatives thereof are also included.

  Moreover, the polymer A can use the polymer of the viscosity normally used for a synthetic fiber. Although not particularly limited, for example, if the polyester polymer is polyethylene terephthalate, the intrinsic viscosity (IV) is preferably 0.4 to 1.5, and preferably 0.5 to 1.3. It is more preferable. Moreover, if it is a polypropylene terephthalate, it is preferable that it is IV0.7-2.0, and it is more preferable that it is 0.8-1.8. Or if it is polybutylene terephthalate, it is preferable that it is IV0.6-1.5, and it is more preferable that it is 0.7-1.4. For example, if the polyamide polymer is nylon 6, the intrinsic viscosity [η] is preferably 1.9 to 3.0, and more preferably 2.1 to 2.8. The intrinsic viscosity or intrinsic viscosity is described in G. It is measured by the method.

The polymer A has a melt viscosity at a temperature used for melt spinning, and a polymer having a shear viscosity of ¹ to 10,000 [Pa · sec] at a shear rate of 10 sec ⁻¹ is usually used. 000 [Pa · sec]. The melt viscosity is H., which will be described later. It can be measured by this method.

  The content of the polymer A in the fiber of the present invention is preferably 50% by weight or more because it is a main component. In particular, since the strength is preferably high in fiber physical properties, the content of the polymer A in the fiber is preferably as high as possible, preferably 70% by weight or more, more preferably 80% by weight or more, and still more preferably 85% by weight. % Or more. Moreover, since the fiber of this invention contains the polymer B, the polymer A has 99 weight% or less preferable.

  The fiber of the present invention is a blend fiber comprising the polymer A and a polymer B incompatible with A. Specifically, since the polymer B is incompatible with A, in the polymer component that forms fibers having a fiber cross section perpendicular to the fiber axis direction, the B is in an island shape in the sea of A. Exists. In the present invention, “incompatible” means that the polymer A and the polymer B are not compatible with each other in the molecular chain size order of the polymer, that is, the average of the islands formed by the polymer B in the polymer A. The size (length corresponding to the shortest diameter of the island) refers to that having a size of at least 10 nm. When the polymer A and the polymer B are compatible, that is, when the average size of the island-shaped polymer B is 10 nm or less, the formed fiber does not have a discontinuous hollow portion in the fiber axis direction. (In this case, it is no longer a “solid fiber”) or a fiber in which a hollow portion necessary for use in the present invention is not sufficiently developed, that is, a fiber having inferior lightness, and the rubber of the present invention It can no longer be applied to the composition and thus to the tire.

  The polymer B in 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. Examples of the polymer include polyamide polymer, polyolefin polymer and other vinyl polymers, fluorine polymer, silicone polymer, elastomer, polycarbonate polymer, and cyclized polycondensation of carboxylic acid anhydride and diamine. Polyimide polymer, polyamideimide polymer, polyetherimide polymer, polybenzimidazole polymer formed by reaction of dicarboxylic acid ester and diamine, other polysulfone polymer, polyethersulfone polymer, aliphatic polyether Synthetic polymers such as polymer, aromatic polyether polymer, polyphenylene sulfide polymer, polyetheretherketone polymer, polyetherketoneketone polymer, polyarylate polymer, cellulose polymer, Chitin, etc. derivatives of chitosan, polymers derived from natural polymers, and the like other diverse polymers.

  More specifically, for example, polyolefins or other vinyl polymers in which a monomer having a vinyl group is synthesized by an addition polymerization reaction such as radical polymerization, anionic polymerization, or cationic polymerization, or a ring-opening polymerization reaction can be given. . Examples of polyolefins include homopolymers, copolymers, and derivatives of polyethylene, polypropylene, polybutylene, and polymethylpentene, and other vinyl polymers include polystyrene, polyacrylic acid, polymethacrylic acid, and polymethacrylic acid. Although polymers such as methyl, polyacrylonitrile, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene chloride, polycyanidene chloride, and copolymers and derivatives thereof are mentioned, polymers synthesized by these addition polymerization reactions or ring-opening polymerization reactions Among them, a polyolefin polymer can be mentioned first as a preferable polymer from the viewpoint of low critical surface tension or low density described later.

  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 The polyolefin used as is mentioned. Among these polyolefins, a polyolefin having a main repeating structure of propylene, butene, or methylpentene is preferable because of its high melting point and low critical surface tension described later, and the main repeating structure in which propylene or methylpentene accounts for 80 mol% or more. A homopolymer or copolymer of polyolefin having In such a copolymer in which propylene or methylpentene accounts for 80 mol% or more, the copolymer is not particularly limited, but, for example, an aliphatic hydrocarbon or alicyclic group having 5 or more carbon atoms. Examples thereof include a vinyl compound having a hydrocarbon, an aromatic hydrocarbon, or a derivative thereof in the side chain. In particular, polyolefins having methylpentene as the main repeating structure are excellent in that the melting point is as high as 200 ° C. or higher and the critical surface tension is low. Examples of the polyolefin include TPX manufactured by Mitsui Chemicals, but are not particularly limited thereto.

  In addition, a polyolefin polymer having a cyclic structure derived from norbornene or tetracyclododecene, which is synthesized by ring-opening polymerization or addition polymerization of an alicyclic monomer, for example, represented by the following chemical formula 1, chemical formula 2, or chemical formula 3, Can be mentioned.

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. N represents the degree of polymerization and is a natural number of n ≧ 10. Viscosity can be controlled by setting it as arbitrary n.

  Examples of those having the structures of Chemical Formulas 1 to 3 include, for example, Arton (registered trademark) manufactured by JSR Corporation, ZEONOR (registered trademark) manufactured by Nippon Zeon Co., Ltd., ZEONEX (registered trademark), and Polyplastics Corporation. Although TOPAS (registered trademark) manufactured by, etc. may be mentioned, polyolefin having a cyclic structure derived from norbornene or tetracyclododecene is not particularly limited thereto.

  The polyolefin-based polymer used as the polymer B may be a homopolymer using one kind of monomer alone, or may be a copolymer using a plurality of kinds. It may be a copolymer obtained by copolymerizing with a vinyl compound. 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 aliphatic cyclic structure (alicyclic structure). In particular, the polyolefin polymer having the alicyclic structure as a copolymer component is also recognized as the polyolefin polymer having the above-mentioned cyclic structure, and examples include Apel (registered trademark) manufactured by Mitsui Chemicals, Inc. The polyolefin polymer having an alicyclic structure is not limited to this.

  Among the polyolefin polymers exemplified as preferred among these polymers, a polyolefin polymer having propylene and / or methylpentene as a main repeating unit, or a cyclic polymer in that the formed hollow portion of the fiber is high. A polyolefin polymer having a structure and a copolymer polyolefin polymer having an alicyclic structure are preferred.

  As the polymer B, among the polymers synthesized by the aforementioned addition polymerization reaction or ring-opening polymerization reaction, styrene, acrylic acid are preferable from the viewpoint of critical surface tension or glass transition temperature (Tg) described later. , Vinyl polymers using methacrylic acid, methyl methacrylate, or acrylonitrile as the main repeating structure. In particular, a vinyl polymer using styrene or methyl methacrylate as the main repeating structure is preferable because Tg is as high as 90 ° C. or higher, and when the fiber used in the present invention is used, the lightness described later is increased. Further, when these styrene, acrylic acid, methacrylic acid, methyl methacrylate, or acrylonitrile is used as the main repeating structure, a plurality of these may be copolymerized, and in particular, acrylonitrile is used as the second component. When the polymer B is used as the polymer B, the miscibility when the polymer A is a polyester polymer is excellent, and the lightness is further improved. The transparency of the resin itself is also excellent.

  Examples of the polymer B include a polyether polymer in addition to the polyolefin polymer or the vinyl polymer. Of these, aromatic polyether polymers represented by polyphenylene ether are preferred. The polyphenylene ether may be a homopolymer mainly composed of phenylene oxide, or may be a copolymer obtained by copolymerizing the second component, and is added in an amount that does not impair the gist of the invention. It is also possible to use a modified polyphenylene ether obtained by alloying a material containing a product, that is, a polystyrene polymer, a polyamide polymer, a polyester polymer, a polyolefin polymer, or the like. Examples of the polyether polymer 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. Examples include Zylon (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., Art Rex (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., and Artley (registered trademark). Needless to say, the polyether polymer mentioned as the preferred polymer B is not limited thereto.

  Alternatively, the polymer B 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., Teflon (registered trademark) manufactured by Idemitsu Petrochemical Co., Ltd., etc. The system polymer is not limited to these.

  The polymer B in the present invention may be a crosslinked polymer (hereinafter sometimes referred to as a crosslinked polymer) in the various polymers listed above. Compared to uncrosslinked polymers composed of the same monomers, crosslinked polymers have very high glass transition temperatures or very high melt viscosities, so that they do not deform at all or hardly deform when heated. do not do. Accordingly, the manufacturing method described later is very preferable because a hollow portion discontinuous in the fiber axis direction which is characteristic in the present invention is easily generated. Here, "crosslinking" generally refers to the joining of long linear polymer molecular chains connected by monomers by chemical bonds, and as a crosslinking method, divinyl compounds, sulfur compounds, epoxy compounds, or isocyanates are used. Add a cross-linking agent such as a compound in the polymerization stage of the polymer or in the melting stage after the polymerization, add a catalyst such as a peroxide to the polymer, and crosslink it with a radical reaction by heating. And ionic bonds are formed by using, and after polymer particles are formed, high energy energy such as light and radiation is applied later to partially bond a part of the polymer. The term “crosslinking” as used herein means that when the polymer is not crosslinked, when the crosslinked polymer is added to a solvent that dissolves within 20 hours at 20 ° C., 24 hours have elapsed in the solvent at 20 ° C. If it does not dissolve, it is defined as “crosslinked”. Whether the polymer is dissolved or not is the polymer after evaporation of the solvent, and the polymer shape remains more than 90% on average with respect to the maximum diameter for 10 or more polymers compared to the polymer shape before dissolution. Suppose that what you are not dissolving.

  In addition, as a crosslinked polymer, what is generally a fine particle having an average diameter of 10 μm or less can be suitably employed, and the average particle diameter is preferably 5 μm or less, more preferably 3 μm or less. As for the lower limit of the average diameter, it is preferable that the smaller the diameter is, the smaller the shape of the hollow part in the fiber can be. However, when it is excessively small, there is a possibility of aggregation. More preferably, it is 0.05 μm or more. Further, spherical particles are particularly preferable. Here, the spherical shape means that the ratio of the minimum diameter to the maximum diameter of the particles is 0.9 or more. As examples, for example, Tospearl (registered trademark) manufactured by GE Toshiba Silicone Co., Ltd., Chemisnow (registered trademark) manufactured by Soken Chemical Co., Ltd., particles made of crosslinked silicone, particles made of crosslinked polystyrene, crosslinked poly Particles made of acrylic, etc., or other various cross-linked polymers are preferably used.

  As the polymer B in the present invention, one of various polymers listed above may be used alone, or a plurality of types may be used in combination as long as the gist of the invention is not impaired.

The polymer B used for the fiber of the present invention is preferably lighter than the polymer A in order to enhance the lightness, that is, the density is preferably smaller, but from the viewpoint that the weight can be further reduced, the density is 1.0 g / More preferably, it is not more than cm ³ . When the density of the polymer B is 1.0 g / cm ³ or less, the lightness of the fiber itself applied in the present invention is further increased, and as a result, the lightness of the tire formed from the rubber composition of the present invention is increased. Increased and preferable. The polymer B is more suitable as the density is smaller, preferably 0.95 g / cm ³ or less, and particularly preferably 0.90 g / cm ³ or less. In the polymer B, the density is 1.0 g / cm ³ or less, for example, the above-mentioned polyolefin, ethylene, propylene, butene, methylbutene, methylpentene, ethylpentene, hexene, ethylhexene, octene, Decene, tetradecene, octadecene or the like can be used as a monomer. Particularly polypropylene with propylene as the main monomer density 0.91 g / cm ^3, and polymethylpentene specific gravity 0.83 g / cm ³ using methylpentene as a main monomer, it is preferred as having a small density. These polyolefins may be a homopolymer using one kind of monomer alone, or may be a copolymer using a plurality of kinds. Moreover, the copolymer which copolymerized these olefins and another ethylenically unsaturated compound may be sufficient, Specifically, the vinyl ester of the saturated aliphatic carboxylic acid which has 2-6 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 Acids or acid halides, amides, imides, acid anhydrides and esters of the unsaturated carboxylic acids, styrene or styrene derivatives, acrylonitrile or acrylonitrile derivatives, vinyloxyalkyl alcohols or derivatives thereof, vinyloxyalkyl carboxylic acids or their Ethi such as derivatives Emissions unsaturated compounds. One of these polymers B may be used alone, or a plurality of these polymers B may be used in combination as long as the gist of the invention is not impaired.

  The average molecular weight of the polymer B used in the fiber of the present invention is not particularly limited, but the number average molecular weight is excellent in terms of kneadability with the polymer A, or in view of shape retention and rigidity in the fiber. It is preferably 2,000 to 10,000,000, more preferably 5,000 to 5,000,000, and still more preferably 10,000 to 1,000,000.

  The polymer B used in the fiber of the present invention is preferably 1% by weight or more and 30% by weight or less in terms of being superior in lightness and having excellent yarn physical properties of the fiber itself used in the present invention. It is more preferably 3% by weight or more and 20% by weight or less, and further preferably 3% by weight or more and 15% by weight or less.

  As described above, the polymer B in the present invention can use a wide variety of polymers. However, when a polymer having a maleimide structure is used as a copolymerization component of the polymer, the fiber becomes brittle when used in excess. In particular, when the polymer A is a polyester-based polymer, the interaction with the maleimide structure is strongly expressed, brittleness is easily imparted, and a skin layer may not be formed due to the formation of an excessively fine hollow portion. Therefore, the content of the polymer having a maleimide structure as the copolymer component of the polymer is preferably less than 3% by weight. In general, the maleimide structure is a structure obtained by reaction of maleic anhydride with ammonia or a primary amine, such as N-alkylmaleimide, N-cycloalkylmaleimide, or N-phenylmaleimide. An N-phenylmaleimide structure is known as one that easily interacts strongly with a polymer and easily embrittles. When the polymer B has the maleimide structure, it can be a lightweight fiber having a sufficient lightness with a content of less than 3% by weight as described above. However, when the content is 3% by weight or more, the lightweight fiber is imparted with brittleness rather as a side effect, and it is difficult to exhibit sufficient lightness. On the other hand, a hollow portion is formed near the surface layer of the fiber. The necessary skin layer is not easily formed in the present invention, the hollow portion in the fiber is easily crushed, and the basic fiber properties such as the strength and elongation of the fiber are easily deteriorated. There are things that cannot be done. Examples of the polymer having a yellowish maleimide structure include styrene maleimide polymers (type: MS-NA, etc.) manufactured by Electrochemical Co., Ltd. The identification of the maleimide structure is described in J. It is measured by the method.

  The polymer B used for the fiber of the present invention makes it easy to form a hollow portion at the aforementioned blend interface, and as a result, the fiber is excellent in light weight, and in turn, the light weight of the tire of the present invention is remarkably excellent. The critical surface tension of the polymer B is preferably 35 dyne / cm or less, more preferably 33 dyne / cm or less, and further preferably 32 dyne / cm or less. Moreover, although the critical surface tension of the polymer B is preferably as low as possible, the critical surface tension of the polymer B usually obtained is 10 dyne / cm or more. The preferred polymer B having a critical surface tension of 35 dyne / cm or less is preferably composed of propylene and / or methylpentene in an amount of 80 mol% or more among the polyolefins composed of the above-mentioned olefin monomers or other ethylenically unsaturated compounds. A homopolymer or copolymer, a vinyl polymer used as a main repeating structure selected from styrene, acrylic acid, methacrylic acid, methyl methacrylate, or acrylonitrile, or a main repeating structure, a polyolefin polymer having a cyclic structure, or Examples thereof include copolymer polyolefin polymers having an alicyclic structure, and homopolymers or copolymers in which methylpentene accounts for 80 mol% or more are particularly preferable.

  Further, the critical surface tension of the polymer A in the present invention is not particularly limited. However, as described above, when the discontinuous hollow portion is formed in the fiber axis direction, the releasability from the polymer B is higher. Therefore, it is preferably higher than 35 dyne / cm, more preferably 38 dyne / cm or more. For example, a polyester polymer such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate has a critical surface tension of about 43 to 46 dyne / cm, and an aliphatic polyester such as polylactic acid or polyglycolic acid has a critical surface tension of about 36 dyne / cm. cm. In addition, copolymer components that can increase the critical surface tension, for example, a copolymer polyester obtained by copolymerizing a component having a polar group such as sulfoisophthalate or a phosphate, co-polymerize these components having a polar group. Compared to unpolymerized polyester, it is preferable because it can have a larger critical surface tension. Nylon 6 and nylon 6, 6 have a critical surface tension of 46 dyne / cm. The critical surface tension is described in F. It is defined by the method.

The melt viscosity of the polymer B used for the fiber of the present invention is usually a polymer having a shear rate of 10 sec ^{−1 and} a shear viscosity of 10 to 10,000 [Pa · sec] at the melt spinning temperature, preferably 100 to 100 ° C. 5,000 [Pa · sec]. The melt viscosity is H., which will be described later. It can be measured by this method.

  In the fiber of the present invention, as described above, when the polymer B forming the island component has a glass transition temperature higher than that of the polymer A, the polymer B is less likely to be deformed at the time of stretching. The lightness of the fiber obtained by easily forming a hollow part discontinuous in the axial direction is high. Here, the glass transition temperature (Tg) of the polymer B is preferably 5 ° C. or more higher than the glass transition temperature (Tgp) of the polymer A in the sense that the deformation temperature has a clear difference. Here, the glass transition temperature (Tg) means E. It is defined by the method. The Tg is more preferably 10 ° C. or more higher than Tgp, more preferably 30 ° C. or more, and particularly preferably 50 ° C. or more. When Tg is higher than Tgp by 5 ° C. or more, not only is it manifested by interfacial debonding between polymer A and polymer B in the formation of the hollow part during stretching, but also the splitting due to brittleness rather than deformation of polymer B itself. Further, since the peeling occurs, the weight is further increased and it becomes very excellent. Furthermore, also in melt spinning, the polymer B is preferable because it solidifies at a higher temperature than the polymer A and forms an island structure that is advantageous for the formation of the hollow portion. The glass transition temperature (Tg) of the polymer B is preferably 85 ° C. or higher, more preferably 90 ° C. or higher, and 110 ° C. or higher in that it is more suitable for generating a hollow part. It is even more preferable that the temperature is 130 ° C. or higher. As the polymer B satisfying this, a vinyl polymer used as a main repeating structure selected from styrene, acrylic acid, methacrylic acid, methyl methacrylate, or acrylonitrile alone or in plural, and a polyolefin polymer having a cyclic structure Or a copolymerized polyolefin polymer having an alicyclic structure, the aforementioned aromatic polyether polymer, the aforementioned polycarbonate polymer, a polysulfone polymer (such as Udel (registered trademark) of Teijin Amoco Engineering Plastics), polyethersulfone Polymers (Amoco's Radel A (registered trademark), BASF's Ultra Zone E (registered trademark), Sumitomo Chemical's Sumika Excel (registered trademark), etc.), polyarylate polymers (Unitika U polymer (registered trademark)) )Such It is mentioned as such is preferred. For example, the glass transition temperature Tgp of a polyester polymer suitably used as the polymer A is about 72 ° C. for polyethylene terephthalate, about 47 ° C. for polypropylene terephthalate, and about 24 ° C. for polybutylene terephthalate. Polylactic acid is observed at about 58 ° C, polycyclohexanedimethanol terephthalate at about 87 ° C, and polyethylene naphthalate at about 122 ° C.

  The polymer A or polymer B used for the fiber of the present invention is, for example, a hollow portion of the fiber of the present invention when the rubber composition obtained by adding the fiber of the present invention is vulcanized and used for tires. In order to avoid melting and crushing and losing lightness, it is preferable that the vulcanization temperature has a melting point (Tm) higher than a general 190 ° C. Here, the melting point (Tm) means E. It is defined by the method. In this case, particularly with respect to the polymer A, an aromatic polyester polymer or a polyamide polymer such as nylon 6, nylon 6, 6 or the like is preferable in that it has a high melting point.

  In the fiber of the present invention, although the polymer A and the polymer B need to be incompatible, the miscibility is so bad that even if kneading is sufficiently performed, the fiber cannot be formed because the compatibility is excessively poor. There is a case. Therefore, a compatibilizer may be included. The compatibilizing agent in the present invention controls the dispersion diameter of the polymer B by changing the interaction at the blend interface to increase the miscibility of the polymer B when the polymer B is contained in the polymer A which is the sea. A compound. 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.

  Moreover, as a high molecular compound mentioned as a compatibilizing agent, what is necessary is just to use a high molecular compound with high compatibility or affinity with respect to each of the polymer A and the polymer B, for example, a polystyrene polymer, a polyacrylate type | system | group. Polymer, polymethacrylate polymer, poly (vinyl alcohol-ethylene) copolymer, poly (vinyl alcohol-propylene) copolymer, poly (vinyl alcohol-styrene) copolymer, poly (vinyl acetate-ethylene) copolymer, poly (vinyl acetate-propylene) Copolymers, poly (vinyl acetate-styrene) copolymers such as vinyl polymers or copolymers, ionomers, polysaccharides, polyalkylene oxides or poly (alkylenes) with improved heat resistance and melt plasticity by chemical modification of the side chain moiety Coxides of alkylene oxides and vinyl derivatives, such as xoxide-ethylene) and poly (alkylene oxide-propylene) copolymers, or derivatives of polyalkylene oxide, copolymers of alkylene terephthalate and alkylene glycol, alkylene terephthalate and poly (alkylene oxide) glycol Examples thereof include polymers such as copolymers, copolymers of alkylene terephthalate and polyalkylene diol, and the like. Among them, considering the fact that the effect as a compatibilizing agent is great and the yarn physical properties when the fiber of the present invention is formed are good, polystyrene polymer, polyacrylate polymer, polymethacrylate polymer, alkylene terephthalate and Preferred are copolymers of alkylene 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. The compatibilizer in the present invention is not limited to these.

  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 (4) can be used.
_{- [(CH 2) a -O} ] m - ··· (4)
Examples of satisfying the formula (4) 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 (5).
_{- {[(CH 2) a} -O] m - [(CH 2) b -O] n} x - ··· (5)
As satisfying the formula (5), 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 (4) or (5) may be used alone or in a range not impairing the gist of the invention. You may use what combined 2 or more types in the range which does not impair the main point of invention.

  One of these compatibilizers which are low molecular weight compounds or high molecular weight compounds may be used alone, or two or more may be used in combination as long as the gist of the invention is not impaired. Although not particularly limited, as compatibilizers, polyethylene oxide Alcox (registered trademark) manufactured by Meisei Chemical Industry, Hytrel (registered trademark) manufactured by Toray DuPont, and polystyrene resin styrene styrene manufactured by Nippon Steel Chemical Co., Ltd. (Registered trademark) and the like can be mentioned as preferable ones.

  Further, the content of the compatibilizing agent is 10 to 200% by weight based on the polymer B in that the compatibilization is expressed more effectively and the fiber properties of the resulting fiber are excellent. Is preferable, and it is more preferable that it is 20 to 100 weight%.

  The fiber of the present invention is a fiber obtained by blending the polymer A and the polymer B, but the hollow portion discontinuous in the fiber axis direction in the fiber is dense and excellent in lightness. The average dispersion diameter of the polymer B in the vertical fiber cross section is preferably 5 μm or less. The fiber of the present invention is a fiber in which the polymer B is blended. As described above, when the polymer A forms a sea component and the polymer B forms an island component, the island component is discontinuous in the fiber axis direction. It exists in a decentralized or elongated form. Therefore, the area of the blend interface between the polymer A and the polymer B becomes very large, and when the fiber of the present invention is formed, a hollow portion that is discontinuous in the fiber axis direction in the fiber cross section perpendicular to the fiber axis direction. As a result, the weight is excellent. However, when the island component in the fiber is continuous in the fiber axis direction, that is, when the fiber before forming the hollow portion is a core-sheath composite fiber or a sea-island composite fiber, it is no longer a blended fiber but a composite interface. The area of (the interface between the core and the sheath or the interface between the sea and the island) is much smaller than that of the blended fiber, and the hollow portion is not generated or is greatly reduced and is extremely poor in lightness.

  Further, as described above, when the average dispersion diameter in the fiber cross section perpendicular to the fiber axis direction of the polymer B is 5 μm or less, the area of the blend interface becomes very large as described above, and accordingly, the discontinuity in the fiber axis direction is accompanied. In addition to increasing the number of hollow parts and making the fibers excellent in lightness, the generated hollow parts are not excessively large and are unlikely to become fiber defects, so the fiber strength does not decrease and is excellent. It will be. However, when the average dispersion diameter in the fiber cross section perpendicular to the fiber axis direction of the polymer B is larger than 5 μm, the area of the blend interface decreases, so the number of hollow portions tends to decrease and the lightness tends to be inferior. It is in. Alternatively, the fiber strength may be lowered. The average dispersion diameter in the fiber cross section perpendicular to the fiber axis direction of the polymer B is preferably smaller than the single yarn diameter of the fiber, preferably 3 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm. It is as follows. The ratio of the average dispersion diameter to the diameter of the fiber cross section perpendicular to the fiber axis direction (in other words, the fiber diameter) is such that more hollow portions are formed or the fiber physical properties are excellent. The average dispersion diameter of the island components] is preferably 5 or more, more preferably 10 or more, and even more preferably 100 or more. The incompatibility and average dispersion diameter in the fiber of the polymer B are described later in D.C. It is defined as the average value of values obtained by confirmation or measurement by the method.

  Although the fiber of the present invention is not particularly limited, it is desirable that the change in form caused by vulcanization when used as a tire material is small. Therefore, the shrinkage rate when kept in a 160 ° C. heated atmosphere for 15 minutes. The (dry heat shrinkage) is preferably 50% or less, more preferably 30% or less, and further preferably 25% or less.

  The fiber strength of the fiber of the present invention is preferably as high as possible, and is preferably 4.0 cN / dtex or more in consideration of practicality. In particular, when used in a tire as in the present invention, it is required to be a strong material. The strength of the fiber is more preferably 4.2 cN / dtex or more, further preferably 4.5 cN / dtex or more, and particularly preferably 4.7 cN / dtex or more. And although this intensity | strength is so high that it is preferable, in order to prevent that a hollow part destroys beforehand as intensity | strength of the fiber at the time of forming a hollow part, it is preferable to set it as the intensity | strength of 10 cN / dtex or less, and 8 cN / dtex or less It is more preferable to set the strength. The fiber strength is determined by A. described later. It is measured by the method.

  Further, the fiber of the present invention preferably has excellent shape stability of the fiber itself, so that the breaking elongation of the fiber at 20 ° C. is preferably 100% or less, more preferably 60% or less, More preferably, it is 40% or less. Further, the lower limit of the elongation of the fiber is not particularly limited, but is preferably 3% or more, more preferably 5% or more as achievable in production. The elongation at break of the fiber is described in A. It is measured by the method.

  In the fiber of the present invention, a polymer other than the polymer A, the polymer B, and the above-described preferable compatibilizer can be blended within a range not impairing the gist of the present invention.

  The apparent specific gravity of the fiber of the present invention is preferably 1.20 or less. The apparent specific gravity of the fiber is an index of the lightness of the fiber itself, and if the apparent specific gravity is 1.20 or less, it is very excellent in lightness and preferable. The apparent specific gravity of the fiber is preferably 1.10 or less, more preferably 1.05 or less, and particularly preferably 1.00 or less. Further, although the smaller the apparent specific gravity is, the better and preferable, it is possible to produce and produce a fiber having an apparent specific gravity of usually 0.10 or more, and a general use of 0.40 or more, as the lower limit can be produced. The apparent specific gravity of the fiber is described later in B. It is measured by the method.

  The fiber of the present invention may be subjected to a suitable dip treatment when used in a rubber composition. When the dip treatment is performed, the fiber is preferably heat-treated in a heating furnace at 230 ° C. or lower, more preferably 150 to 230 ° C. for a certain period of time, and at the same time, preferably 0.6 g / d or lower, more preferably under stretch conditions It is preferable to treat by dipping in a dipping solution while stretching under a tension of 0.2 to 0.5 g / d. The dip treatment liquid is not particularly limited, and preferred is an R · F · L treatment solution composed of resorcin / formaldehyde / latex used for the adhesion treatment of synthetic fiber and rubber, and this R · F · Examples thereof include a treatment liquid obtained by adding a cocondensate (trade name: Denabond (manufactured by Nagase Kasei Kogyo Co., Ltd.)) composed of parachlorophenol and resorcin / formaldehyde to the L treatment liquid. After dipping, the fiber is obtained by cutting to a desired fiber length.

  As a means for producing the fiber of the present invention, generally used synthetic fiber production methods can be employed. For example, a melt spinning method in which a melt of a resin is discharged from a nozzle is preferably used. In this melt spinning method, as described above, a core-sheath type composite spinning method may be employed to form a skin layer having no hollow portion on the fiber surface layer, and the skin layer may be disposed as a sheath component.

  In the case of a fiber (undrawn yarn) obtained by the melt spinning method, if necessary, it is once cooled below the glass transition temperature of the polymer A, preferably 100 to 10,000 m / min, more preferably 500. After taking up at a take-up speed of 8000 m / min, particularly preferably 1000 to 6000 m / min, without taking up or once taken up, preferably at a draw ratio of 1.5 times or more, more preferably 3.0 It is preferable that the drawing process is performed at a draw ratio of at least twice, particularly preferably at a draw ratio of 4.0 times or more, and a drawing process at a high drawing tension or a drawing false twisting process at a high tension in the case of a filament. Here, as a method of developing the hollow portion, a method that can apply a high elongation stress to the fiber and develop the hollow portion as described above is preferably employed. For example, an undrawn yarn obtained by winding by melt spinning is highly Examples include a method of stretching at a magnification, a method of continuously stretching at a high magnification without winding up an undrawn yarn during spinning, and a method of drawing at a high speed of 4500 m / min or more in spinning. Or a method of shrinking the polymer B in the fiber by heating the running fiber or irradiating specific light, and any method can be adopted. Among these methods, the undrawn yarn obtained by winding up the fiber taken up by melt spinning is drawn at a high magnification of 4.5 times or more because the process is simple and the control of the hollow portion generation is easy. Method, a method of drawing undrawn yarn obtained by putting fibers taken up in spinning into a container at a high magnification of 4.5 times or more, or after taking up the undrawn yarn at the time of spinning, without winding or in a container A method of continuously stretching at a high magnification of 4.5 times or more without adding is preferable. In particular, in the step of drawing, the fiber is heated or heated pin-like, roller-like, plate-like, heated liquid heat medium (for example, water, silicone oil, glycol, etc.), steam-like heat. The film is heated by a medium (such as water vapor) or a non-contact heater using heated gas or electromagnetic waves as another medium, and then stretched in one or more stages. In order to generate the hollow portion more effectively, a pin-like object, a plate-like object, a heated liquid heat medium (for example, water, silicone oil, glycol, etc.) or a vapor heat medium (water vapor) under high tension Etc.) is preferably drawn at the same time that the undrawn yarn is heated. In particular, in the hot drawing in a hot water bath using hot water heated to 40 ° C. to 90 ° C. as a heating medium, the hollow portion Is particularly preferable since a fiber excellent in lightness can be obtained. The stretched fiber may be wound as it is, but is preferably wound after being heat-set at a temperature equal to or higher than the stretching temperature + 10 ° C. Alternatively, in the case of a short fiber, after being drawn, it is crimped and then subjected to a heat treatment, and is cut to a length of 0.05 mm to 200 mm. Alternatively, heat treatment may be performed later.

  In the drawing false twisting process, the fiber is heated after being drawn or not heated, or the undrawn yarn is heated in a pin-like product, a roller-like product, a plate-like product, a heated liquid heat After heating with a medium (for example, water, silicone oil, glycol or the like), a vapor-like heat medium (water vapor or the like), a non-contact type heater, or the like, false twisting is performed using a disk-like material or a belt-like material. Although the stretched false twisted fiber is not particularly limited or is not particularly limited, it is preferably wound after being heat set at a temperature equal to or higher than the stretch false twist temperature + 10 ° C.

  When the fiber of the present invention is used for a rubber composition, particularly when used for a tire, it is assumed that the fiber of the present invention is used under severe conditions over time such as exposure to strong sunlight or washing with water. A light-resistant agent may be blended or shrink-proof processing may be performed so that the strength does not deteriorate or change in dimensions in a short time.

  The fiber of the present invention is for a rubber composition, but the type of rubber used in the rubber composition is not particularly limited as long as the properties of the fiber of the present invention are not impaired, and may be appropriately selected according to the purpose and application. Selected. For example, natural rubber, various butadiene rubbers, various styrene-butadiene copolymer rubbers, polyisoprene rubber, acrylonitrile butadiene rubber, chloroprene rubber, ethylene-propylene-diene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene. -Butadiene copolymer rubber, isoprene-butadiene copolymer rubber, and the like are exemplified, and these rubbers may be used alone or in combination of a plurality of types of rubbers in any content. .

  The fiber content when the fiber of the present invention is used in a rubber composition is 3% by weight or more from the viewpoint of improving the lightness of the rubber composition itself and, consequently, a tire formed from the rubber composition. Preferably, it is more preferably 5% by weight or more. Further, the content of the fiber of the present invention is preferably as it is increased from the viewpoint of improving the lightness of the tire, but when it is excessively large, the processability as a rubber composition may be inferior, so 50% by weight or less is preferable. 30% by weight or less is more preferable.

  In the fiber of the present invention, a foaming agent may be retained within a range that does not impair the gist of the present invention. As will be described later, the foaming agent foams at the time of vulcanization to generate air bubbles that are preferable in the tire, and effectively contributes to the steering stability of the tire. The foaming agent may be held on the fiber surface, that is, adhered to the fiber surface by various methods such as spraying or coating, or the fiber is immersed in the foaming agent itself or a liquid or fluid containing the foaming agent at normal or high pressure. Alternatively, it may be impregnated and a foaming agent may be held at any place in the fiber, particularly in the hollow part of the fiber. In that case, as the foaming agent preferably used, for example, at least one selected from azo compounds, nitroso compounds, hydrazine compounds and bicarbonates can be used. Specifically, azodicarbonamide, N, N′-dinitrosopentamethylenetetramine, 4,4′-oxybis (benzenesulfonylhydrazide), hydrazodicarbonamide, barium azodicarboxylate, sodium hydrogen carbonate and the like are exemplified as preferable ones. The products are commercially available under the trade names of “Vinihole”, “Cellular”, “Neoselbon”, “Exceller”, “Spancell”, “Selbon”, etc., respectively.

  The foaming agent preferably has a decomposition temperature of 120 to 180 ° C, more preferably 140 to 160 ° C. In this temperature range, it is possible to form uniform bubbles having a sufficient size during molding of the rubber composition or subsequent vulcanization. In addition, when the decomposition temperature of this foaming agent is too high, it is also possible to adjust a decomposition temperature to 120-180 degreeC by combined use with foaming adjuvants, such as urea. The content of the foaming agent in the fiber is preferably 0.01 to 500 parts by weight.

  The fiber of the present invention may contain a small amount of additives such as a flame retardant, a lubricant, an antioxidant, a crystal nucleating agent, and a terminal group sealing agent as long as the gist of the invention is not impaired. Further, reinforcing agents, vulcanizing agents, vulcanization accelerators, cross-linking agents, cross-linking accelerators, various vulcanized oils, anti-aging agents, and fillers that function effectively when made into rubber compositions such as carbon black and silica. Various compounding agents blended in a general tire rubber composition such as a softening agent and a plasticizer can be added to the fiber in advance, and the blending amount of these compounding agents can also be a general amount. In addition, these additives may be blended in the fiber as a whole, or only in a specific part of the fiber, that is, in the hollow part of the fiber or in any part other than the hollow part of the fiber. May be.

  Hereinafter, the present invention will be described specifically and in detail by way of examples. Naturally, 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 fiber strength and elongation at break Using a Tensilon tensile tester manufactured by Orientec, the filamentous fiber before being cut into short fibers was measured at an initial sample length of 200 mm and a tensile speed of 200 mm / min, and measured five times. The average value was used as the measured value. When measuring fibers cut into short fibers, measurement is possible up to a fiber length of approximately 5 mm. Hold the upper and lower portions of the fiber 20% at a time, and pull the remaining unpinned portion as the initial sample length. The measurement was performed at a speed of 50 mm / min, and an average value measured five times was used as a measurement value.
B. Measurement of apparent specific gravity of fiber The apparent specific gravity of the fiber was measured and calculated by the following methods (a) and (b).
(A) When the apparent specific gravity of the fiber is 0.659 or more JIS-L-1013 (1999) 8.17.1 (issued by the Japanese Standards Association, chemical fiber filament yarn test method) If the apparent specific gravity of the fiber is 1 or more at a temperature of 20 ° C. ± 0.1 ° C., an aqueous NaBr solution is used. If the apparent specific gravity of the fiber is between 1 and 0.789, water is reduced to the heavy liquid. If the apparent specific gravity of the fiber is between 0.789 and 0.659 in the mixed liquid using ethyl alcohol as the liquid, the mixed liquid using ethyl alcohol as the heavy liquid and n-hexane as the light liquid, After the fiber was left for 5 minutes, the equilibrium state of the float / sink was confirmed. As described in 8.17.1 above, the specific gravity value of the mixed liquid that did not float or sink was measured, and the average of the specific gravity values measured for the five fibers. The value was defined as a measured specific gravity value (Q).
(B) When the apparent specific gravity of the fiber is less than 0.659 Using a multifilament, a tubular knitting with a gauge width of 20 / inch (2.54 cm) and a pitch length of 1 mm is produced to be 100 g ± 10 g. After measuring the weight in advance and fixing the weight and volume previously known to the cylinder, submerged in ion-exchanged water prepared at 4 ° C. ± 1 ° C. and defoamed by ultrasonic for 5 minutes, The volume of the tubular knitting was measured, and the average value of the specific gravity values of the 10 cloths measured was taken as the measured specific gravity value (Q).
C. Single fiber diameter, confirmation that the hollow part is not communicated in the fiber axis direction, confirmation of the diameter of the hollow part and calculation of the average diameter, calculation of the hollow ratio of the fiber, average number of hollow parts, inclination of the hollow part in the fiber cross section Confirmation, Confirmation of Skin Layer After placing a single fiber on a carbon tape affixed to a sample stage and performing a platinum deposition process (deposition film pressure: 25-50 angstrom treatment time: about 120 seconds), a focused ion beam ( FIB) Cutting-Rough cutting (current: about 7000 pA, processing time: about 20 minutes) with a Ga focused ion beam accelerated at an accelerating voltage of 30 kV using a scanning electron microscope (SEM) observation apparatus (STRATADB235 manufactured by FEI). ), and precision cutting (current: about 3000 Pa, a treatment time in two steps of approximately 4 minutes) in an atmosphere of vacuum of 1.4 × ^{10 -13} Pa, fiber When observing the cross section, the sample is cut perpendicularly to the fiber axis direction, and when observing the fiber longitudinal section, the length near the fiber center of the sample is parallel to the fiber axis direction and is at least five times the fiber diameter. Cut with. 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 tilt of 52 degrees and an acceleration voltage of 5 kV, a magnification of 200 to 150,000 The fiber cross section and the fiber longitudinal section were observed at an arbitrary magnification required for each item below. Since the cross-sectional photograph is usually a photograph observed at a sample inclination of 52 degrees, the circumscribed circle of the original fiber shape of the obtained fiber cross-sectional photograph has a ratio of the minor axis to the major axis of 0.79. It looks like an ellipse. The diameter of the single fiber is the same as the diameter of the circumscribed circle of the fiber cross section perpendicular to the fiber axis of the fiber, and the major axis of the ellipse is the circumscribed circle diameter, that is, the single fiber diameter is obtained.
(A) Confirmation that the hollow portion is not communicated in the fiber axis direction About the discontinuity, there is a hollow portion interrupted in the fiber axis direction in one longitudinal section photograph, or 5 than the fiber diameter. The photographs were overlapped with respect to five arbitrary fiber cross-sections that were greatly separated from each other by a factor of 2 or more, and it was confirmed that there was no overlap of the hollow portions or the positional relationship of the hollow portions was different in each photograph. In addition, when it had a discontinuous hollow part in the fiber axis direction, it evaluated as (circle), and when this hollow part was all continuous or did not have a hollow part, it evaluated as x.
(B) Confirming the diameter of the hollow part, digitizing the image of the fiber cross section observed at an average diameter calculation magnification of 80000 times or more into black and white, and using the computer software WinROOF (version 2.3) manufactured by Mitani Shoji Co., Ltd. The area of each of the recognizable hollow portions existing on the image was calculated, and the diameter of the hollow portion was calculated by determining that the area was substantially circular from the area value. Of these, those having a diameter of 20 nm or more were recognized as hollow portions in the present invention, and the average diameter was calculated by obtaining an average value for all the hollow portions.
(C) Calculation of fiber hollow ratio The total sum of the areas of all hollow portions that can be recognized at a magnification of 80000 times or more existing on the cross-sectional image is calculated, and the value calculated from the ratio to the area of the fiber cross-section is used. The average of the hollow ratios of the five fibers calculated in the same manner for five arbitrary fiber cross sections separated by a factor of 5 or more from the fiber diameter was used as the hollow ratio of the fibers used.
(D) Average number of hollow parts In the fiber cross section, the number of all hollow parts for which the diameter of the hollow part was calculated was counted, and the average value of the hollow part was determined for any of the five fiber cross sections far apart from the fiber diameter. Calculation was made to be the average number of hollow portions of the used fiber.
(E) Confirmation of the inclined structure of the hollow part in the fiber cross section In the photograph of the fiber cross section perpendicular to the fiber axis direction of the fiber, the cross section shape of the fiber is (1 ) Similar to fiber cross-sectional shape, (2) Shares fiber cross-sectional shape and figure center, (3) The distance r from the figure center to the outer side of the figure is the distance from the center of the fiber cross-section to the outer side When the outer layer portion and the inner layer portion are divided according to a figure satisfying the condition of half of R, d1 is a relationship between the average diameter d1 of the hollow portion existing in the inner layer portion and the average diameter d2 of the hollow portion existing in the outer layer portion. When satisfying that /d2≧1.01, it was determined to have an inclined structure (◯).
(F) Confirmation of skin layer About each hollow part calculated | required by the above-mentioned (b) term, the side nearest to the fiber surface of a hollow part about the hollow part nearest to a fiber surface layer recognized as a hollow part whose diameter is 20 nm or more The distance from the fiber surface was determined, the distance was regarded as the skin layer and the thickness of the skin layer, and the ratio between the single fiber diameter determined above and the thickness of the skin layer was determined.
D. Confirmation of incompatibility and average dispersion diameter in fiber of polymer B Dye the block in which the fiber is embedded in epoxy resin using ruthenium oxide solution, and cut it in the direction perpendicular to the fiber axis direction with an ultramicrotome. An ultra-thin section having a single fiber cross section is prepared, and an arbitrary magnification of 20,000 to 100,000 times at an acceleration voltage of 75 kV with a transmission electron microscope (TEM) observation device (H-7100FA type manufactured by Hitachi, Ltd.). The cross-sectional observation was carried out with, and the resulting photograph was digitized in black and white. The cross-sectional photograph was subjected to image analysis using WinROOF (version 2.3) manufactured by Mitani Corporation, a computer software, to confirm the incompatibility and the average dispersion diameter of the polymer B. Regarding the average dispersion diameter, the areas of all of the top 100 polymers B in the descending order of the polymer B present on the cross-sectional photograph were calculated, and the polymer B calculated by determining that the area was substantially circular from the area value. The average value of the diameters was calculated. Further, regarding incompatibility, if the average dispersion diameter was 10 nm or more, it was judged to be incompatible.
E. Measurement of Glass Transition Temperature (Tgp or Tg) and Melting Point (Tm) Using a differential scanning calorimeter (DSC-2) manufactured by PerkinElmer, the glass transition temperature (Tgp or Tg) was measured with a 10 mg sample at a heating rate of 16 ° C./min. Tm and Tg are defined as follows: after observing the endothermic peak temperature (Tm1) of crystal melting once measured at a heating rate of 16 ° C / min, hold at a temperature of Tm1 + 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 was defined as Tm.
F. Measurement of critical surface tension In a film made of polymer A or polymer B (limited to those that can form a film with polymer B), pure water 72.8 dyne / cm, ethyl alcohol (special grade or higher) 22.3 dyne / cm, Using 5 kinds of liquids of dioxane 33.6 dyne / cm, hexane 18.4 dyne / cm, 20% aqueous ammonia 59.3 dyne / cm, liquid on a flat sample at 20 ° C., humidity 60%, standing condition The surface of the liquid used was measured by measuring the angle between the solid plane in contact with the droplet and the surface of the droplet in contact with the air layer as the contact angle θ. Plot cos θ against tension (Zisman plot), and extrapolate the points where the surface tension when fully wetted, ie cos θ = 1, is extrapolated To determine the force.
G. Measurement of Intrinsic Viscosity (IV) and Intrinsic Viscosity [η] In the case of a polyester polymer, a sample was dissolved in an orthochlorophenol solution and measured at 25 ° C. using an Ostwald viscometer. In the case of polyamide polymer, the sample was dissolved in formic acid and measured by the same method as for polyester polymer.
H. Measurement of melt viscosity Using Capillograph 1B manufactured by Toyo Seiki Co., Ltd., under a nitrogen atmosphere, a barrel diameter of 9.55 mm, a nozzle length of 10 mm, a nozzle inner diameter of 1 mm, and a piston pushing speed of 1, 2, 5, 10, 20, Measurements were made for 50, 100, 200, and 500 mm / min, and the obtained values were plotted with a shear rate [sec ⁻¹ ] on the X axis and a shear viscosity [Pa · sec] on the Y axis on a logarithmic scale, and a shear rate of 10 sec. The shear viscosity value at ^-1 was determined. And the average value of the value calculated | required 5 times was made into the measured value of melt viscosity. Regarding measurement time, 5 measurements were completed within 30 minutes in order to prevent deterioration of the sample.
I. 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.
J. et al. Evaluation of Steering Stability of Tire The vehicle was run on an ice board at an initial speed of 30 km / h, and the braking distance when braking was measured. The larger the value, the better the braking.
K. Riding comfort evaluation The results of scoring the riding comfort of each tire by five test drivers on a conventional tire (evaluation is 5 points) by a 10-point method from 0 to 10 points (average value of 5 people) Shown in points. The larger the value, the better the ride comfort.
L. Evaluation of lightness of tire The obtained tire weight was expressed as an index with the conventional tire as 100. The smaller the value, the higher the lightness.

<Manufacture of fiber>
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, 0.02 part by weight of 85% aqueous solution of phosphoric acid as a coloring inhibitor and antimony trioxide as a polycondensation catalyst 0.07 part by weight, 0.05 part by weight of cobalt acetate tetrahydrate as a toning agent was added, and polycondensation reaction was performed to obtain a commonly used polyethylene terephthalate (hereinafter referred to as PET) having an IV of 0.65.
Using this PET, melt spinning was performed using a biaxial extruder type melt spinning machine at a spinning temperature of 285 ° C. using a die having a round shape, a diameter of 0.25 mm, and a number of holes of 36. The polyester multifilament fiber having a round cross-sectional shape of 398 dtex-36 filaments was obtained by taking up at a take-up speed of a minute and then winding up. No yarn breakage occurred during spinning, and the yarn making property was excellent.
When the obtained PET fiber is stretched, the yarn feeding speed of the yarn feeding roller is 10 m / min, and a length of 80 cm is used to stretch between the first roller and the second roller installed next to the yarn feeding roller. The bath length was set at a bath temperature of 80 ° C., and the fiber was passed through the bath to draw at a draw ratio of 5.0 times. The second roller was heat-treated at 130 ° C. and then cooled. The yarn was wound after being cooled to a Tg of PET or less by a roller. The results of Comparative Example 1 are shown in Table 1.

Comparative Example 2
When performing the melt spinning using the biaxial extruder type melt spinning machine using the PET obtained in Comparative Example 1 as the polymer A, styrene-maleic anhydride-N manufactured by Denki Kagaku Kogyo Co., Ltd. is used as the polymer B. Except for containing 6% by weight of phenylmaleimide copolymer resin (Denka IP, type MS-NA, hereinafter Denka IP), melt spinning was performed in the same manner as in Comparative Example 1, the fiber cross-sectional shape was round, and the total fineness was 395 dtex. A multifilament with 36 filaments was obtained. And when extending | stretching using a warm water bath like the comparative example 1, all were extended | stretched by 4.5 times with the same yarn feeding speed, and the fiber was obtained. When the fiber is stretched, the fiber is fragile, and since the fiber strength was low because the fiber could not be stretched as high as in Comparative Example 1, the hollow portion produced by stretching was generated up to the outer edge of the fiber. When the ratio of the thickness of the skin layer to the single fiber diameter was 1/1200, the skin layer was not substantially formed. When the fiber was bent, the bending of the fiber was not recovered, and a bent portion of the fiber, which was presumed to be a collapse of the hollow portion, occurred.

Examples 1-3
Using PET obtained in Comparative Example 1 as the polymer A, when performing melt spinning using a biaxial extruder type melt spinning machine, the polymer B was obtained as Example 1: Mitsui Chemicals polymethylpentene (TPX ( Registered trademark), type RT18, hereinafter referred to as PMP), Example 2: Arton (registered trademark, type F5023, hereinafter referred to as Arton) of poly (tetracyclododecene monoester) manufactured by JSR Corporation, Example 3: Polyplastics ( Co., Ltd. ethylene / norbornene copolymer resin TOPAS (registered trademark, Example 7 is also the same as type 6017, hereinafter TOPAS), and for Example 1, Hytrel (registered trademark, type 4057) manufactured by Toray DuPont as a compatibilizing agent Except for containing each of these, melt spinning was performed in the same manner as in Comparative Example 1, and the fiber cross-sectional shape was round and the number of filaments was 36. To obtain a multifilament fiber (fineness of Example 1: 389dtex, fineness of Examples 2 and 3 392dtex). And when extending | stretching using a warm water bath similarly to the comparative example 1, all were extended | stretched by 5.5 times with the same yarn feeding speed, and the fiber was obtained, respectively.

Example 4
In Example 2, nylon 6 amylan (CM1017, hereinafter referred to as nylon) manufactured by Toray Industries, Inc. was used instead of PET as the polymer A, except that the content of Arton was 12% by weight and the spinning temperature was 260 ° C. A blended multifilament having a round cross-sectional shape of 276 dtex-36 filaments was obtained by the same spinning method as in Example 1. The draw ratio was 4.6 times, and the hot water bath and the second roller heated to a liquid temperature of 40 ° C. and the second roller were heat treated at 100 ° C. in the same manner as in Comparative Example 1 to obtain a fiber having a round cross-sectional shape. Obtained.

Example 5
Dimethyl terephthalate 130 parts (6.7 mole parts), 1,3-propanediol 114 parts (15 mole parts), calcium acetate monohydrate 0.24 parts (0.014 mole parts), lithium acetate dihydrate To a low polymer obtained by transesterifying 0.1 parts (0.01 mole parts) of salt and distilling off methanol, 0.065 parts of trimethyl phosphate and 0.134 parts of titanium tetrabutoxide were added. The polycondensation reaction was performed while distilling off 1,3-propanediol, and a chip-shaped prepolymer was obtained. The obtained prepolymer was further subjected to solid phase polymerization at 220 ° C. under a nitrogen stream to obtain polytrimethylene terephthalate (hereinafter referred to as PPT) of IV1.15.
In Example 4, the PPT was used instead of nylon as the polymer A, and 12% by weight of Mitsui Chemicals' Appel (registered trademark, type 6015T, hereinafter referred to as Appel) was used as the polymer B. The same melt spinning as in Example 4 was carried out except that 15% by weight of Hytrel (registered trademark, type 4057) manufactured by Toray DuPont, which was the same as No. 1, was used. Extensive stretching was performed in the same manner as in Comparative Example 1 except that the hot water bath heated to 60 ° C. and the second roller were heat-treated at 120 ° C. to obtain a fiber having a round cross-sectional shape.

Example 6
In Example 2, melt spinning and stretching were performed in the same manner as in Example 2 except that a base having a slit length L of 0.5 mm, a slit width d of 0.08 mm, a hole depth of 0.4 mm, and a hole number of 24 shown in FIG. 2 was used. Then, an irregular cross-section fiber having a flat (−) cross-sectional shape was obtained.

Example 7
In Example 3, the Y-shaped hole shape shown in FIG. 3 has a slit length X0.5 mm, a slit width Y0.08 mm, a hole depth 0.4 mm, and a number of holes of 24. The same melt spinning and stretching as in Example 3 was carried out except that the die was used to obtain a three-leaf type irregular cross-section fiber shown in FIG.

Examples 8-10
In Example 8, PET of Comparative Example 1 is used, in Example 9, PPT of Example 5 is used, and in Example 10, polybutylene terephthalate (type 1100S, IV0.85, hereinafter referred to as PBT) manufactured by Toray Industries, Inc. is used. In Example 8, Chemisnow (registered trademark) grade MX-150 (crosslinked acrylic) manufactured by Soken Chemical Co., Ltd., Chemisnow SX-130H (crosslinked polystyrene) was used in Example 9, and GE Toshiba in Example 10 as the crosslinked polymer. Tospar (registered trademark) grade XC99-A8808 (cross-linked silicone) manufactured by Silicone Co., Ltd. was added in an amount of 5% by weight (Examples 8 and 9) and 10% by weight (Example 10), respectively. The same melt spinning and stretching as in Comparative Example 1 except that the draw ratio was changed to 4.2 times. The except for using 4.0 times perform the same melt spinning and drawing as in Example 5, to obtain the fiber, respectively. The critical surface tension of these three crosslinked polymers could not be measured.

<Manufacture of rubber composition>
Using SBR1502 manufactured by JSR Corporation, which is a diene rubber, as the rubber, various additives shown in Table 2 were added in an amount (% by weight) based on 100 parts by weight of the rubber, and Comparative Example 1 and Examples 1 to 10 described above. A rubber composition and a tire were prepared by the following method using the fibers prepared in step 1 and the fiber amount shown in Table 3 (addition amount of fiber (wt%) in 100 parts by weight when the rubber composition was formed) and fiber length. Produced. The fibers shown in Table 3 were produced so as to have the fiber length by cutting with a cutter after making a tow of about 100,000 decitex.
First, using a 1.7L Banbury manufactured by Kobe Steel Co., Ltd., after kneading other than sulfur and a vulcanization accelerator at 135 ° C., sulfur and a vulcanization accelerator were added to the resulting kneaded product to form a biaxial roller. And kneaded to obtain a rubber composition. A tire tread was formed using the obtained rubber composition and vulcanized at 150 ° C. for 30 minutes to obtain a 195 / 60R15 size radial tire for passenger cars.
The tires were evaluated for lightness, and a normal passenger car equipped with the tires was used to conduct tests on steering stability and riding comfort on a test course. In Comparative Example 1, the performance was almost the same as that of the conventional tire, but in Examples 1 to 10, the lightness of the tire was improved, the handling stability on the ice plate, and the ride comfort were also improved. Received an evaluation of improvement.

  The fiber for rubber composition of the present invention is contained in a rubber composition, and when it is used to form a tire, it has excellent lightness and handling stability, so it greatly contributes to reducing fuel consumption of vehicles for environmental problems. To do. The tire using the present invention is suitably used for so-called automobiles such as wheelbarrows, bicycles, motorcycles, private cars, trucks, cultivators, military vehicles, space development vehicles, marine development vehicles and the like.

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 the nozzle | cap | die hole shape which can obtain the fiber (flat cross section) of the irregular cross section in this invention. It is explanatory drawing which shows the nozzle | cap | die hole shape which can obtain the fiber (three-leaf type cross section) of the odd-shaped cross section in Example 2 of this invention. It is explanatory drawing which shows an example which divided the outer layer part and inner layer part for judging an inclined structure with the fiber of 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 d: Slit width (flat-section thread cap)
L: Slit length (Flat section thread cap)
X: Slit length Y: Slit width P: Polymer A
Q: Hollow part S: Polymer B
(A): Outer layer part (I): Inner layer part

Claims (7)

  The polymer A has a fiber-forming ability and the polymer B is incompatible with A, and has 100 or more hollow portions in a fiber cross section perpendicular to the fiber axis direction, and the hollow portions are fiber axes. A fiber for a rubber composition having a fiber length of 0.05 to 30 mm, having a skin layer that is not communicated in a direction and has no hollow portion on a fiber surface layer. A fiber having a fiber cross-sectional shape in which the center of gravity of the fiber cross-section exists in the fiber in a fiber cross-section perpendicular to the fiber axis direction, and the fiber cross-sectional shape depends on a figure that satisfies the following condition (1) When divided into the outer layer portion and the inner layer portion, d1 / d2 ≧ 1.01 in relation to the average diameter d1 of the hollow portion existing in the inner layer portion and the average diameter d2 of the hollow portion existing in the outer layer portion. The fiber for a rubber composition according to claim 1, wherein the fiber is a rubber composition.
(1) The figure is similar to the fiber cross-sectional shape, shares the fiber cross-sectional shape and the figure centroid, and the distance r from the figure centroid to the figure outer side of the figure is from the centroid to the outer side of the fiber cross-section. 1/2 of distance R   The fiber for rubber composition according to claim 1 or 2, wherein the fiber has a cross section having a deformity of 1.2 or more.   The fiber for a rubber composition according to any one of claims 1 to 3, wherein an average diameter of a hollow portion in a fiber cross section perpendicular to the fiber axis direction is 0.10 to 1.50 µm.   The fiber for rubber composition according to any one of claims 1 to 4, wherein the hollow ratio is 10 to 65%.   The fiber for a rubber composition according to any one of claims 1 to 5, wherein the polymer A is at least one selected from a polyester-based polymer, a polyamide-based polymer, and a polyolefin-based polymer.   The fiber for rubber composition according to any one of claims 1 to 6, wherein the polymer B is a crosslinked polymer.

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