JP4882238B2 - Rubber composition and tire - Google Patents

Description

  The present invention relates to a rubber composition and a tire. More specifically, the present invention relates to a tire excellent in lightness and handling stability, a vulcanized rubber that can be suitably used for a tread of the tire, and a rubber composition that can be suitably used as a raw material of the vulcanized rubber.

  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, nothing was foreseen or suggested for a suitable fiber structure for the tire to have better stiffness and handling 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 have excellent lightness and unstable road surface, in particular, a tire excellent in handling stability on an icy and snowy road surface, a tread of the tire, etc. It is an object of the present invention to provide a vulcanized rubber suitable for a structure portion that requires slip suppression on a stable road surface, and a rubber composition suitable as a raw material for the vulcanized rubber.

  The present invention relates to a tire excellent in lightness and handling stability, a vulcanized rubber suitable for the tire, and a rubber composition suitable as a raw material for the vulcanized rubber, and in earnest, It has been found that by using a rubber composition using fibers having a specific fiber structure, the disadvantages of the prior art can be eliminated and further advantages can be imparted, and the present invention has been achieved.

That is, the present invention is a rubber composition comprising at least one rubber and the hollow fiber, the hollow fiber may have a fiber forming ability, a polymer A which have a high melting point (Tm) than 190 ° C. And a polymer B that is incompatible with A, and has 100 or more discontinuous hollow portions that do not communicate with each other in the fiber axis direction in a fiber cross section perpendicular to the fiber axis direction. A rubber composition is provided.

  According to the present invention, the 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. Further, it is possible to provide 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 provided is a vulcanized rubber suitable for a structure that needs to suppress slip on an unstable road surface such as a tread of the tire, or a rubber composition suitable as a raw material of the vulcanized rubber. Can do.

  The hollow fiber used in the present invention refers to one having an elongated shape and a ratio of a length to an apparent diameter of at least 10, for example, a long fiber (filament made by manufacturing a conventional synthetic fiber) ), Short fibers (staples), or cut fibers that are cut to a length of 30 mm or less, but not particularly limited as long as they are fibrous, but have a good dispersibility in the rubber composition, 30 mm or less. It is preferable that the length is 0.05, more preferably 0.05 to 20 mm, and particularly preferably 0.1 to 10 mm. The fiber diameter of the hollow 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 hollow parts or the average diameter of the hollow parts is more preferable, or that the rubber composition has good dispersibility as described above. Preferably, it is 200 μm or less, more preferably 30 μm or less. Further, the lower the fiber diameter, the better the dispersibility when it is contained in the rubber composition, and the frictional force when it is made into a tire is improved and the operation stability is excellent, but the hollow fiber is preferable. Is preferably 0.01 μm or more, and more preferably 0.1 μm or more in that stable lightness can be maintained.

  The hollow fiber used in the rubber composition of the present invention has 100 or more hollow parts in the fiber cross section perpendicular to the fiber axis direction, and the hollow parts do not communicate in the fiber axis direction and exist discontinuously. . In the present invention, when the hollow fiber is used, by having 100 or more hollow portions, the hollow portions disperse stress, so that the hollow portions are not easily crushed, and the above-described lightness or operational stability is permanently maintained. sell. The number of the hollow portions is preferably as large as possible because stress can be dispersed, and in view of the number that can be actually formed, it is preferably 300 to 100,000. Furthermore, the number of the hollow portions is particularly preferably 500 to 50,000 from the viewpoint of imparting better operational stability. The number of the hollow portions is described later in C.I. Defined as the average number of hollows measured in the term.

  Moreover, it is preferable that this hollow part is 0.10-1.50 micrometers in average diameter of the hollow part in a fiber cross section. When the average diameter is within this range, the hollow fiber itself, and thus, the hollow portion having a size suitable for dispersing stress applied to the hollow fiber as well as being excellent in light weight when a tire is formed. Therefore, the hollow part is hardly crushed. The average diameter is more preferably 0.15 to 1.00 μm, and particularly preferably 0.20 to 0.75 μm. The average diameter of the hollow portion is described later in C.I. Measured by the term.

  The hollow portion of the hollow fiber used in the present invention is not continuous in the fiber axis direction and is discontinuous. By having the hollow part, as described above, the tire containing the hollow fiber of the present invention is very light. 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 following relationship between the polymer A and the polymer B forming the lightweight fiber: (1) a blend of the polymer A and the 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 in the fiber axis direction of the hollow portion is described later in C.I. It is confirmed by the paragraph.

The hollow part of the hollow fiber used in the present invention has an outer layer part and an inner layer part in a fiber cross section perpendicular to the fiber axis direction, and the shape of the fiber cross section satisfies the following conditions (1) to (3). In this case, 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) Similar to fiber cross-sectional shape.
(2) Sharing the fiber cross-sectional shape and the figure center.
(3) The distance r from the center of the figure to the outer side of the figure is half of the distance R from the center of the fiber cross section to the outer side.
This relates to the size (diameter) of the hollow part in the fiber cross section perpendicular to the fiber axis direction, and the diameter of the hollow part increases from the fiber outer layer part toward the inner layer part, that is, the hollow part in the fiber cross section It means that it has an inclined structure and is preferable because the hollow portion of the hollow fiber is not easily crushed. Thereby, regarding the lightness of the tire when it is included in the rubber composition and formed as a tire, the hollow portion of the hollow fiber is less likely to be crushed and the lightness of the tire is further enhanced.

  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, it has an inclined structure. Although it is recognized that the value of d1 / d2 is large, the hollow portion of the hollow fiber is less likely to be crushed. The value is more preferably d2 / d1 ≧ 1.30, and 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 10.0 or less is appropriate. For example, in the schematic diagram of the hollow fiber shown in FIG. 4, the outer layer portion is indicated by (A) and the inner layer portion is indicated by (A). The inclined structure of the hollow portion is described later in C.I. It is confirmed by the paragraph.

  The hollow fiber used in the present invention preferably has a deformed cross section having a fiber cross section perpendicular to the fiber axis direction with a deformity of 1.2 or more. The method of calculating the irregularity will be described later, but when the irregularity is 1.2 or more, in addition to the light weight due to the hollow portion of the hollow fiber itself, there is a space where rubber is difficult to enter the outer peripheral portion of the fiber. When it is expressed and the tire is made of the rubber composition of the present invention, it is preferable because the weight is further improved. 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. Alternatively, with respect to the inclined structure of the hollow portion described above, the greater the degree of deformity, the more the lightness is improved due to a synergistic effect. From this, the degree of deformity is preferably 1.3 or more. It is more preferably 4 or more, and particularly preferably 1.5 or more. The upper limit is not particularly limited, but is preferably 7.0 or less, more preferably 5.0 or less, more preferably 3.0 or less in view of retention of the deformity in the production stage of the hollow fiber. Is even more preferable, and 2.0 or less is particularly preferable.

  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 in the case where the hollow fiber used in 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 C shape, a well shape, a − shape, a + shape, and the like can be given as general names. Multi-leaf type, polygonal type, gear type, and star type are preferable, and it is more preferable that they are well-type,-type, + type, and multi-leaf type, and multi-leaf type in that it is easy to form a space in the outer periphery of the fiber. It is particularly preferred that A multi-leaf type cross-section refers to a cross-section having irregularities and the same number of concave and convex portions, and the multi-leaf type hollow fiber formed continuously in the fiber longitudinal direction is made of rubber on the outer periphery of the fiber. 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 manifested when a tire made of the rubber composition of the present invention is formed. In addition, when the hollow fiber in 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 hollow fiber itself has good rigidity and lightness. It is preferable that the number of leaves is 3 or more. On the other hand, in view of the fiber-forming properties of the hollow fibers and the fiber properties of the resulting hollow fibers, or the fact that the cross-sectional shape is easily maintained, it is preferably a multi-leaf type irregular cross section having 8 or less leaves, and a multi-leaf having 6 or less leaves. It is more preferable that the cross section be a deformed shape.

  In addition, when the cross-sectional shape of the hollow fiber is a negative-shaped cross-section, in addition to the irregularity defined above, the width (d) and length (L) of the cross-section as shown in FIG. The ratio L / d is preferably 1.2 or more. The L / d is preferably as large as possible, but in view of the fiber-forming property of the hollow fiber, it can be generally 10 or less. In the case of the-shaped irregular cross-section fiber, although the space between the fibers does not develop so much, the inclined structure of the hollow portion, which is said to be difficult to be crushed, easily develops, and the tire comprising the rubber composition of the present invention When formed, the lightweight property is maintained, which is very preferable.

  Furthermore, when the cross-sectional shape of the hollow fiber is a well-shaped or + -shaped cross section, the lightness of the tire made of the rubber composition of the present invention can be obtained by the expression of the space between the fibers and the expression of the inclined structure of the hollow part. Is retained and is very excellent.

  The hollow fiber used in the present invention may have a skin layer having no hollow portion on the fiber surface. By having the skin layer, the surface of the hollow fiber is not deteriorated due to bending or wear, and the durability against crushing of the hollow portion existing inside the fiber is increased, and the light weight is excellent. When the skin layer is present, 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 is inferior in lightness. Therefore, the thickness of the skin layer is preferably 1/5 or less of the diameter D1 of the circumscribed circle, more preferably 1/10 or less, and even more preferably 1/15. Moreover, since the effect of a skin layer will be lose | eliminated when too thin, it is preferable that it is 1/10000 or more of D1. This skin layer is formed simultaneously with the hollow portion in the process of forming the hollow portion described later. That is, the skin layer is composed of a blend polymer of polymer A and polymer B.

  Further, the hollow ratio indicating the volume ratio of the hollow portion of the hollow fiber affects the lightness of the tire made of the rubber composition of the present invention, and the higher the hollow ratio, the more excellent the lightness of the tire. This 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 described later in C.I. Measured by term and defined as mean value.

  The hollow fiber used in the rubber composition of the present invention is mainly composed of the polymer A having fiber forming ability. As the polymer A having fiber-forming ability, a wide variety of polymers 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 be used as a hollow fiber in the present invention in a rubber composition and can impart a preferable lightness when a tire is formed. .

  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. A polyester polymer is 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 hollow fiber used in 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. Further, since the hollow fiber contains the polymer B, the polymer A is preferably 99% by weight or less.

  The hollow fiber used in the present invention is a blend fiber composed of the polymer A and the 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, and the average size of islands formed by the polymer B in the polymer A (The shortest diameter equivalent length of the island) refers to one 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 hollow fiber but a “solid fiber”), or a hollow fiber in which a hollow part necessary for use in the present invention is not sufficiently developed, that is, a hollow fiber inferior in lightness. Thus, it can no longer be applied to the rubber composition of the present invention, and thus 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, for example, polyolefin polymers having a cyclic structure represented by the following chemical formula 1, chemical formula 2, or chemical formula 3, which are synthesized by ring-opening polymerization or addition polymerization of an alicyclic monomer, can be given.

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

  As what has the structure of Chemical formula 1-3, JSR Co., Ltd. Arton (registered trademark), Nippon Zeon Co., Ltd. ZEONOR (registered trademark), ZEONEX (registered trademark), Polyplastics Co., Ltd. Although TOPAS (trademark) etc. are mentioned, the polyolefin which has a cyclic structure is not restrict | limited to these in particular.

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

  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 hollow fiber in the present invention preferably has a density of 1.0 g / cm ³ or less. When the density of the polymer B is 1.0 g / cm ³ or less, the lightweight property of the hollow fiber itself applied in the present invention is further enhanced, and thus the lightweight property of the tire formed from the rubber composition of the present invention. Is 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.

  Further, the average molecular weight of the polymer B used for the hollow fiber in 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. 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 for the hollow fiber in the present invention is more lightweight, and the content of the fiber itself of the fiber used in the present invention is 1% by weight or more and 30% by weight or less in that the fiber property is excellent. Preferably, it is 3 to 20% by weight, more preferably 3 to 15% by weight.

  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, it reacts with the maleimide structure and easily becomes brittle, so the polymer having a maleimide structure as a copolymerization component of the polymer has a content of less than 3% by weight. It is preferable. 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 reacts with a polymer. 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 not only does not exhibit sufficient lightness, but also basic fiber properties such as strength and elongation of the hollow fiber. May become inferior, may not withstand practical use, and may not be applicable to the present invention. 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 hollow fiber in the present invention makes it easy to form a hollow portion at the aforementioned blend interface, and as a result, the hollow fiber is excellent in light weight, and the light weight of the tire of the present invention is remarkably excellent. Thus, 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 hollow fiber in the present invention is usually a polymer having a shear spinning temperature of 10 sec ^{-1 and} a shear viscosity of 10 to 10,000 [Pa · sec], preferably 100. ˜5,000 [Pa · sec]. The melt viscosity is H., which will be described later. It can be measured by this method.

  In the hollow fiber used in the present invention, as described above, the polymer B forming the island component easily forms a discontinuous hollow portion in the fiber axis direction when the fiber is stretched, and the resulting hollow fiber has high lightness. In this respect, 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. 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. Since 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 is manifested by splitting and delamination of polymer B itself, It is lighter and more excellent. Further, 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 a hollow portion, so that the light weight is also improved. 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.

  In the present invention, the polymer A or the polymer B used for the hollow fiber in the rubber composition of the present invention is used for tires by vulcanizing the rubber composition as described later. In order to avoid 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 hollow fiber used in the present invention, although the polymer A and the polymer B need to be incompatible with each other, the fiber cannot be formed even if kneading is sufficiently performed because the compatibility is excessively poor. Miscibility may be poor. Therefore, a compatibilizing agent may be contained. 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 that the effect as a compatibilizing agent is great and the yarn physical properties when the hollow fiber in the present invention is formed are good, polystyrene polymer, polyacrylate polymer, polymethacrylate polymer, alkylene terephthalate And copolymers of alkylene glycol, 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. The compatibilizers include, but are not limited to, polyethylene oxide Alcox (registered trademark) manufactured by Meisei Chemical Industry, Hytrel (registered trademark) manufactured by Toray DuPont, and polystyrene-based styrene resin manufactured by Nippon Steel Chemical. (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 hollow fiber are excellent. It is preferably 20 to 100% by weight.

  The hollow fiber used in the present invention is a fiber obtained by blending the polymer A and the polymer B, but the discontinuous hollow portion in the fiber axis direction in the fiber is dense and excellent in lightness. The average dispersion diameter of the polymer B in the fiber cross section perpendicular to the fiber axis direction is preferably 5 μm or less. The hollow fiber in the present invention is a fiber in which the polymer B is blended. As described above, when the polymer A forms the sea component and the polymer B forms the island component, the island component is discontinuous in the fiber axis direction. In a dispersed or elongated state. Therefore, the area of the blend interface between the polymer A and the polymer B becomes very large, and when the hollow fiber used in the present invention is formed, the area in the fiber axis direction in the fiber cross section perpendicular to the fiber axis direction is not good. The number of continuous hollow portions is extremely large, and as a result, the light 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. In addition, 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 fiber diameter / island] The average dispersion diameter of the component] 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 hollow fiber used in the present invention is not particularly limited, it is desirable that the shape change due to vulcanization when used as a tire material is small. The shrinkage rate at that time (dry heat shrinkage rate) is preferably 50% or less, more preferably 30% or less, and even more preferably 25% or less.

  The fiber strength of the hollow fiber used in 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. Higher strength is preferable, but fibers with a strength of 10 cN / dtex or less can be obtained at most, and fibers with a strength of 8 cN / dtex or less can be obtained for general use. The fiber strength is described later in A. It is measured by the method.

  The hollow fiber used in the present invention preferably has excellent shape stability of the fiber itself, and therefore, the breaking elongation of the hollow fiber at 20 ° C. is preferably 100% or less, and 60% or less. More preferably, it is more preferably 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 hollow fiber is described in A. It is measured by the method.

  In the hollow fiber used in the present invention, a polymer other than the polymer A, the polymer B, and the above-described compatibilizer may be blended within a range that does not impair the gist of the present invention.

  The apparent specific gravity of the hollow fiber used in the present invention is preferably 1.20 or less. The apparent specific gravity of the hollow fiber is an index of the lightness of the fiber itself, and if the apparent specific gravity is 1.20 or less, it is extremely excellent in lightness and preferable. The apparent specific gravity of the hollow 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 hollow fiber is described later in B. It is measured by the method.

  The hollow fiber used in the present invention may be dip-treated. When the dip treatment is performed, the hollow fiber is preferably heat-treated in a heating furnace at 230 ° C. or less, more preferably 150 to 230 ° C. for a certain period of time, and at the same time preferably 0.6 g / d or less, more preferably under stretch conditions. Is preferably treated 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 the dip treatment, a hollow fiber is obtained by cutting to a desired fiber length.

  As a means for producing the hollow fiber used in the present invention, a commonly used synthetic fiber production method can be employed. For example, a melt spinning method in which a melt of a resin is discharged from a nozzle is suitably used. 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 to After taking up at a take-up speed of 8000 m / min, particularly preferably 1000 to 6000 m / min, without taking up or after taking up once, preferably at a draw ratio of 1.5 times or more, more preferably 3.0 times With the above draw ratio, particularly preferably with a draw ratio of 4.0 times or more, in the case of a drawing process or a filament, a drawing false twisting process is preferably used. Here, as a method for developing the hollow portion, a method in which an elongation stress can be applied to the fiber and the hollow portion can be expressed is preferably employed. For example, an undrawn yarn obtained by winding by melt spinning is drawn at a high magnification. Examples include a method, a method of continuously drawing at a high magnification without winding up an undrawn yarn at the time of spinning, a method of taking up at a high speed of 4500 m / min or more in spinning, or running a wound fiber or running For example, a method may be employed in which the polymer B in the fiber is contracted by heating the fiber in the 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 hollow fiber used in the rubber composition of the present invention is assumed to be used over time, such as being exposed to strong sunlight or washed with water as a tire material, the strength of the hollow fiber deteriorates in a short period of time. In order not to cause dimensional change, a light resistance agent may be blended or shrink-proofed.

  The rubber composition of the present invention comprises at least one rubber. The type of rubber used is not particularly limited as long as it does not impair the gist of the present invention, and can be appropriately selected according to the purpose and application. 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, etc. Examples of these rubbers may be used singly, or a plurality of types of rubbers may be used in any desired content.

  The content of the hollow fiber used in the rubber composition of the present invention is preferably 3% by weight or more from the viewpoint of improving the lightness of the rubber composition itself and, in turn, the tire formed from the rubber composition. More preferably, it is at least wt%. Further, the content of the hollow fiber is preferably as it is increased from the viewpoint of improving the lightness of the tire, but when it is excessively large, the workability of the rubber composition may be deteriorated. More preferably, it is less than wt%.

  In the rubber composition of the present invention, fibers other than the hollow fiber of the present invention may be mixed as long as the gist of the invention is not impaired. That is, other fibers selected from synthetic fibers, semi-synthetic fibers, natural fibers, and the like, for example, cellulose fibers, wool, silk, stretch fibers, acetate fibers, and the like may be mixed.

  The rubber composition of the present invention may contain a foaming agent as long as the gist of the present invention is not impaired. 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. As the foaming agent preferably used in the present invention, 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 foaming agent content is preferably 0.01 to 15 parts by weight with respect to 100 parts by weight of the rubber in the rubber composition of the present invention.

  As the foaming agent that can be used in the present invention, a foaming agent-encapsulating resin containing the above-mentioned foaming agent may be used in order to add the foaming agent to perform uniform dispersion or to obtain uniform foamed cells. The foaming agent encapsulating resin is commercially available from Eiwa Kasei Kogyo Co., Ltd. under the trade name “Cell Powder” and is easily available. The foaming agent-encapsulating resin containing the foaming agent suitably used in the present invention is preferably contained in an amount of 0.5 to 20 parts by weight, more preferably 2 to 8 parts by weight based on 100 parts by weight of rubber. When this content is in a preferred range, the formation of bubbles in the rubber composition is effectively expressed, and the shape stability and hardness characteristics of the vulcanized rubber are excellent. In addition, it is preferable that content of the foaming agent in this foaming agent enclosure resin is 5-65 weight%, and it is more preferable that it is 15-50 weight%.

  The foaming agent-encapsulating resin containing the foaming agent is not particularly limited as a constituent resin, and various types of resins can be used depending on the function and efficacy, but those based on polyolefin-based polymers are available. Preferably used. Here, the “main component” means that the polyolefin polymer is 75% by weight or more, preferably 85% by weight or more of the total resin components, and other components include, for example, unreacted residues of olefin monomers, polymerization Residues such as initiators and catalysts, processing aids, polymers other than polyolefin polymers, and the like. As such polyolefin polymer, at least one selected from polyethylene, polypropylene, poly-4-methylpentene-1, polybutylene-1, and the like can be used, and a mixture or copolymer thereof can also be used. . When a foaming agent-encapsulated resin in which a foaming agent is encapsulated in advance with the polyolefin-based polymer is blended in the rubber composition, it is processed regardless of the softening point of the resin constituting the foaming agent-encapsulating resin as long as it is below the decomposition temperature of the foaming agent. The temperature can be selected, and the coating layer of the resin around the bubbles is formed efficiently and reliably. Further, since this polyolefin-based polymer does not have co-crosslinking properties with the diene-based rubber, the gas-filled resin particles formed during high-temperature processing or vulcanization do not unnecessarily diffuse, and the rubber phase This is preferable because a microcapsule-shaped resin-coated bubble in which the gas-filled resin particle phase is clearly separated can be obtained. In addition, in the air bubbles whose airtightness has been improved by the resin coating, gas release on the mold contact surface during vulcanization hardly occurs, and as a result, the vulcanized rubber has a more uniform dispersion of microcapsule-like bubbles from the surface layer to the center. It is preferable because it is in a state of being. The resin constituting the foaming agent-encapsulating resin containing the foaming agent is preferably a resin that does not have co-crosslinking properties with the diene rubber blended in the rubber composition. In order to prevent co-crosslinking, a compound in which no double bond remains in the main chain of the molecule is preferable.

  The foaming agent-encapsulating resin finally generates gas by decomposition of the foaming agent to become gas-encapsulating resin particles, and the particle diameter of the gas-encapsulating resin particles is preferably 10 to 200 μm, and 50 to 150 μm. It is more preferable. The particle size is preferably an appropriate size because a specific gravity reducing effect and a mechanical strength improving effect when a tire formed from a rubber composition, and thus a rubber composition, is obtained.

  You may mix | blend a process oil with the rubber composition of this invention. Examples of suitable process oils include paraffinic process oil, naphthenic process oil, and aromatic process oil. The amount of the process oil is 1 to 60 parts per 100 parts by weight of diene rubber. The content of parts by weight is preferable, and the content of 1 to 30 parts by weight is more preferable. By including an appropriate amount of process oil, the processability of the rubber composition is improved, the hardness of the rubber is good, and the steering stability of the tire formed from the rubber composition of the present invention is extremely excellent. preferable.

  The rubber composition 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. Furthermore, for general tires such as carbon black and silica reinforcing agents, vulcanizing agents, vulcanization accelerators, crosslinking agents, crosslinking accelerators, various vulcanized oils, anti-aging agents, fillers, softeners, plasticizers, etc. Various compounding agents compounded in the rubber composition can be added, and the compounding amount of these compounding agents can also be a general amount. These additives may be blended in the entire rubber composition, or only in the rubber portion or only in the hollow fiber.

  The rubber composition of the present invention contains rubber, hollow fibers, and, if necessary, various additives such as the vulcanizing agent and vulcanization accelerator described above in ordinary processing equipment such as rolls, Banbury mixers, kneaders, and single screw. It can be obtained by kneading using a multi-screw or the like.

  If the rubber composition of the present invention contains the above-mentioned vulcanizing agent, it is heated and pressurized in a vulcanizer to obtain a vulcanized rubber. When the rubber composition contains a vulcanization accelerator, it is preferable because vulcanization can be efficiently performed.

  The tire of the present invention is produced by a usual method using the above rubber composition. That is, if necessary, the rubber composition of the present invention blended with the additive is extruded in accordance with the shape of each member of the tire at an unvulcanized stage, and molded by a normal method on a tire molding machine. By doing so, an unvulcanized tire is formed. Thereafter, the unvulcanized tire can be heated and pressurized in a vulcanizer to obtain a tire. In particular, when the rubber composition of the present invention is used for a tread rubber or a tread base rubber of a tire, the tread rubber can improve the lightness of the tire itself and the operational stability. And is suitably used as a tread base rubber. In this case, the tire of the present invention is produced by extruding the rubber composition of the present invention to a tread member at an unvulcanized stage and pasting and molding it on a tire molding machine by a normal method. A tire is formed, and then the raw tire is obtained by heating and pressing in a vulcanizer. Note that when the tire is a gas-filled tire, and the gas is filled in the tire, normal or air having a changed oxygen partial pressure, or an inert gas such as nitrogen can be used.

  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 breaking elongation of hollow fiber Using a Tensilon tensile tester manufactured by Orientec Co., Ltd., an initial sample length of 200 mm and a tensile speed of 200 mm / min were measured, and an average value measured five times was used as a measured 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 (published 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, The equilibrium state after the fiber was allowed to stand for 30 minutes was confirmed, and 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 specific gravity value obtained by measuring 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, so that it becomes 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, average diameter of the hollow part, average number of hollow parts, discontinuity in the fiber axis direction of the hollow part, confirmation of the inclined structure of the hollow part in the fiber cross section, calculation of the hollow ratio of the hollow fiber Affixed to the sample stage A single fiber is placed on the carbon tape, and after platinum deposition (deposition film pressure: 25 to 50 angstrom, treatment time: about 120 seconds), focused ion beam (FIB) cutting-scanning electron microscope (SEM) With an observation device (STRAIDB235 manufactured by FEI), with a Ga focused ion beam accelerated at an acceleration voltage of 30 kV, rough cutting (current: about 7000 pA, processing time: about 20 minutes) and precision cutting (current: about 3000 pA, When the fiber cross section is observed in an atmosphere with a degree of vacuum of 1.4 × 10 ⁻¹³ Pa in two steps (processing time: about 4 minutes), the sample is taken in the fiber axis direction. When cutting vertically and observing the longitudinal section of the fiber, the vicinity of the fiber center of the sample was cut in parallel to the fiber axis direction to a length of 5 times or more the fiber diameter. After cutting, using a scanning electron microscope possessed by the apparatus, in an atmosphere with a vacuum degree of 1.4 × 10 ⁻¹⁹ Pa, with a sample inclination of 52 degrees and an acceleration voltage of 5 kV, a magnification of 200 to 100,000 The fiber cross section and the fiber longitudinal section were observed at an arbitrary magnification of the magnification. Since the cross-sectional photograph is a photograph observed at a sample inclination of 52 degrees, the circumscribed circle, the inscribed circle, and the circle with a diameter of D3 are ellipses whose major axis is diameter and minor axis is 0.79 × diameter. It becomes.
(A) The discontinuity in the fiber axis direction of the hollow portion As for the discontinuity, the above-mentioned FIB-SEM method is used to superimpose a photograph on any cross section of any fiber that is 5 times larger than the fiber diameter. Thus, 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 (n = 5). 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) Average diameter of hollow part The image of the fiber cross section photographed by the FIB-SEM method described above was digitized in black and white, and the cross section of the fiber was measured using WinROOF (version 2.3) manufactured by Mitani Corporation of computer software. The area of all the recognizable hollow portions existing on the image was calculated, and the average value was calculated from the diameter of the hollow portion determined from the area value and determined to be substantially circular.
(C) Hollow ratio of hollow fiber Calculate the sum of the areas of all the recognizable hollow portions present on the cross-sectional image, and use the value calculated from the ratio of the fiber cross-sectional area to the fiber diameter described above. Also, the average of the hollowness ratios of the five fibers calculated in the same manner with respect to five arbitrary fiber cross-sections greatly separated by 5 times or more was defined as the hollowness ratio of the hollow fibers used.
(D) Average number of hollow parts In the fiber cross section, the number of all the 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 five fiber cross sections far apart from the fiber diameter. Calculation was made to be the average number of hollow portions of the hollow fibers used.
(E) Confirmation of the inclined structure of the hollow portion in the fiber cross section In the photograph of the fiber cross section perpendicular to the fiber axis direction of the hollow fiber, the cross section shape of the fiber is (1) fiber by the same image analysis method as described above. Similar to the cross-sectional shape, (2) sharing the fiber cross-sectional shape and the graphic center, (3) the distance r from the graphic center to the outer side of the graphic is the distance R from the center of the fiber cross-section to the outer side In the case where the outer layer portion and the inner layer portion are divided according to the figure that satisfies the condition of half, d1 / d2 is related 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. When satisfying that ≧ 1.01, (◯) having an inclined structure.

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 with 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 manufactured and traversed at an arbitrary magnification of 5000 to 1000000 times at an accelerating voltage of 75 kV with a transmission electron microscope (TEM) observation device (H-7100FA type manufactured by Hitachi, Ltd.). Surface observation was performed 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) Measurement was performed with a differential scanning calorimeter (DSC-2) manufactured by PerkinElmer Co., Ltd., with a sample temperature of 10 mg and a heating rate of 16 ° C./min. The definitions of Tm and Tg are as follows: after observing the endothermic peak temperature (Tm1) observed once at a rate of temperature increase 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 of 16 ° C./min, the endothermic peak temperature observed as a step-like baseline deviation is defined as Tg, and the melting temperature of the crystal And the endothermic peak temperature observed as Tm.

F. Measurement of critical surface tension In a film made of polymer A or polymer B, pure water 72.8 dyne / cm, ethyl alcohol (special grade or higher) 22.3 dyne / cm, dioxane 33.6 dyne / cm, hexane 18.4 dyne / cm When 5 drops of 20% aqueous ammonia 59.3 dyne / cm were used and the liquid was placed on a flat sample under the conditions of 20 ° C., 60% humidity and standing, The angle formed by the solid plane in contact with the droplet and the surface of the droplet in contact with the air layer is measured as the contact angle θ, and cos θ is plotted against the surface tension of the liquid used (Zisman plot). The critical surface tension was obtained by extrapolating the plotted points of the surface tension when wetting with water, that is, when cos θ = 1.

G. Measurement of Intrinsic Viscosity (IV) and Intrinsic Viscosity [η] In the case of a polyester polymer, the 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, with a barrel diameter of 9.55 mm, a nozzle length of 10 mm, and a nozzle inner diameter of 1 mm, the piston pushing speed is 1, 2, 5, 10, 20, respectively. 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 [Pascal second] 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. Steering stability evaluation The vehicle traveled on an ice plate 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 Results of scoring the riding comfort of each tire by five test drivers using a 10-point method from 0 to 10 points compared to the conventional tire (evaluation is 5 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 weight of the obtained tire was indicated as an index with the conventional tire as 100. The smaller the value, the higher the lightness.

<Manufacture of hollow fibers>
Comparative Example 1
To a low polymer obtained by ordinary esterification reaction from 166 parts by weight of terephthalic acid and 75 parts by weight of ethylene glycol, 0.03 part by weight of 85% phosphoric acid aqueous solution as a coloring inhibitor and antimony trioxide as a polycondensation catalyst 0.06 parts by weight and 0.06 parts by weight of cobalt acetate tetrahydrate as a toning agent were added to carry out a polycondensation reaction to obtain a commonly used polyethylene terephthalate (hereinafter referred to as PET) having an IV of 0.70.

  Using this PET, melt spinning was performed by using a biaxial extruder type melt spinning machine at a spinning temperature of 290 ° C. using a die having a round hole shape, a hole diameter of 0.3 mm, and a number of holes of 24. A polyester multifilament fiber having a round shape of 265 dtex-24 filaments was obtained. 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.

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: Norbornene resin Arton (registered trademark, type F5023, hereinafter referred to as Arton) manufactured by JSR Corporation, Example 3: TOPAS (registered trademark) manufactured by Polyplastics Corporation , Type 6017, hereinafter TOPAS), and Example 1, except that a compatibilizing agent was added, respectively, and melt spinning was performed in the same manner as in Comparative Example 1, and the multifilament fiber having a round fiber cross section and 24 filaments (Fineness of Example 1: 259 dtex, fineness of Examples 2 and 3 262 dtex). 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 hollow 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 as the polymer A instead of PET, the content of Arton was 10% by weight, and the spinning temperature was 260 ° C. A blended multifilament having a round cross-sectional shape of 223 dtex-24 filaments was obtained by the same spinning method as in Example 1. Except that the draw ratio was 4.6 times, drawing was performed in the same manner as in Comparative Example 1 to obtain a hollow fiber having a round cross-sectional shape.

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 IV1.12.

  In Example 4, the same melting as in Example 4 was conducted except that PPT was used instead of nylon as polymer A, and Appell (registered trademark, type 6015T, hereinafter referred to as Appel) manufactured by Mitsui Chemicals was used as polymer B. Spinning and drawing were performed to obtain a hollow 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 of 0.5 mm, a slit width of 0.08 mm, a hole depth of 0.4 mm, and a hole number of 24 shown in FIG. 3 was used. Thus, a modified cross-section hollow fiber having a three-leaf type cross section was obtained.

Example 7
In Example 3, the same melt spinning as in Example 3 was used except that a + -shaped hole-shaped die having a slit length of 0.5 mm, a slit width of 0.08 mm, a hole depth of 0.4 mm, and a hole number of 24 was used. Drawing was performed to obtain a modified cross-section hollow fiber having a + -shaped cross section.
<Cut hollow fiber>
The fibers obtained in the above-mentioned Comparative Example 1 and Examples 1 to 7 were made into about 10,000 dtex tows and then cut into the lengths shown in Table 3.
<Manufacture of rubber composition>
Using SBR1502 manufactured by JSR Co., Ltd., 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 fiber length and fiber amount shown in Table 3 ( In the case of a rubber composition, the amount of fiber added in 100 parts by weight (% by weight)), first using a 1.7L Banbury manufactured by Kobe Steel, Ltd., except for sulfur and a vulcanization accelerator, 135 ° C. Then, sulfur and a vulcanization accelerator were added to the obtained kneaded material and kneaded with a biaxial roller to obtain each rubber composition. A tire tread was formed using each rubber composition obtained, 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 inferior to that of the conventional tire, but in Examples 1 to 7, 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 being.

  Since the rubber composition of the present invention has excellent lightness and steering stability when a tire is formed, it greatly contributes to a reduction in fuel consumption of the vehicle against environmental problems. The tire of the present invention is suitably used for so-called automobiles such as wheelbarrows, bicycles, motorcycles, private cars, trucks, cultivators, military vehicles, space development vehicles, and marine development vehicles.

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

Explanation of symbols

1: circumscribed circle 2: inscribed circle 3: area included between circumscribed circles 4: inscribed area inside inscribed circle D1: diameter of circumscribed circle D2: diameter of inscribed circle X: Slit length Y: Slit width d: Slit width (flat-section thread cap)
L: Slit length (Flat section thread cap)
P: Polymer A
Q: Hollow part S: Polymer B
(A): Outer layer part (I): Inner layer part

Claims (12)

A rubber composition comprising at least one rubber and the hollow fiber, the hollow fiber may have a fiber forming ability, a polymer A which have a high melting point (Tm) than 190 ° C., A to And a rubber composition comprising 100 or more discontinuous hollow portions that do not communicate with each other in the fiber axis direction in a fiber cross section perpendicular to the fiber axis direction.   2. The rubber composition according to claim 1, wherein the number of hollow portions in the fiber cross section perpendicular to the fiber axis direction of the hollow fibers is 300 to 100,000. In the fiber cross section perpendicular to the fiber axis direction of the hollow fiber, when the fiber cross section is divided into an outer layer part and an inner layer part by a figure that satisfies the following conditions (1) to (3), it exists in the inner layer part 3. The rubber composition according to claim 1, wherein d1 / d2 ≧ 1.01 in relation to an average diameter d1 of the hollow portion and an average diameter d2 of the hollow portion existing in the outer layer portion.
(1) Similar to fiber cross-sectional shape (2) Shares fiber cross-sectional shape and figure center (3) The distance r from the center of the figure to the outer side of the figure is the distance from the center of the fiber cross-section to the outer side Half of R   The rubber composition according to any one of claims 1 to 3, wherein a fiber cross section of the hollow fiber is a deformed section having a deformity of 1.2 or more.   The rubber composition according to any one of claims 1 to 4, wherein an average diameter of a hollow portion in a fiber cross section perpendicular to the fiber axis direction of the hollow fiber is 0.10 to 1.50 µm.   The rubber composition according to claim 1, wherein the hollow ratio of the hollow fiber is 10 to 65%.   The rubber composition according to any one of claims 1 to 6, wherein the polymer A is selected from at least one of a polyester polymer, a polyamide polymer, and a polyolefin polymer.   The rubber composition according to any one of claims 1 to 7, wherein the content of the hollow fiber is 3% by weight or more and 40% by weight or less.   The rubber composition according to any one of claims 1 to 8, wherein the length of the hollow fiber is 0.05 to 20 mm.   A vulcanized rubber obtained by vulcanizing the rubber composition according to any one of claims 1 to 9.   A tire formed by vulcanizing the rubber composition according to any one of claims 1 to 9.   A tire obtained by vulcanizing the rubber composition according to any one of claims 1 to 9 using a part or all of a tread.

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