JPH083371A - Tire for passenger car - Google Patents

Abstract

PURPOSE:To obtain the subject product, excellent in moldability, good in high- speed running properties, wet road surface gripping properties and abrasion resistance by using a rubber composition for a cap tread, having a specific composition and a high elasticity and excellent in processability. CONSTITUTION:This product is obtained by using a rubber composition prepared by blending (A) a fiber-reinforced thermoplastic composition containing (iii) a thermoplastic polymer, having amide groups in its main chain and dispersed as fine fibers in a matrix consisting of (i) a polyolefin and (ii) a vulcanizable rubber and the component (iii) bonded to the components (i) and (ii) with (B) a natural rubber and/ or a polyisoprene, (C) a diene-based rubber except for the component (B) and (D) carbon black in a cap tread part. The amount of the components based on 100 pts.wt. total amount of the rubber components are 1-15 pts.wt. component (iii) and 60-90 pts.wt. component (D). The total amount of the natural rubber or the polyisoprene in the component (A) and the component (B) is 5-40wt.% based on the rubber components. The 300% modulus of a vulcanizate of the composition is >=100kg/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passenger car tire using a rubber composition having a high elastic modulus, a low Mooney viscosity (ML) and excellent workability as a cap tread rubber. Further, the rubber composition used for the tire of the present invention, further carcass in the tire, belts, chafers, tire members such as base tread, beads, and industrial products such as hoses, belts, rubber rolls, rubber crawlers, Can be used.

[0002]

2. Description of the Related Art In general, tires are required to have excellent handling properties, durability, etc., and particularly to have excellent wet skid resistance on wet roads in terms of safety. Further, based on the social demand for resource saving in recent years, in order to reduce dynamic loss in tires, research and development of tires with low rolling resistance, that is, tires with low energy loss are being conducted. The energy loss consumed by the freely rotating tire varies depending on the tire structure and the like, but about 1/2 of the total energy is consumed in the tread portion. Therefore, if the internal consumption of the tread rubber is reduced, the energy loss at the time of rolling of the tire is reduced, and a tire with low rolling resistance can be obtained.

Therefore, it has been attempted to modify the tread rubber so as to reduce the energy loss. However, such rubber modification tends to reduce wet skid resistance. Since the improvement of rolling resistance and the improvement of wet skid resistance are generally contradictory matters, various attempts have been made to improve the tire structure in order to make them compatible. One of the ideas is to make the tread into two layers, a cap tread and a base tread. That is, a cap tread having good wet skid resistance and a base tread having small energy loss are provided in two layers to improve wet skid resistance of the tire and reduce energy loss as a whole.

In addition to wet skid resistance and abrasion resistance, the cap tread rubber is required to have a high elastic modulus due to high-speed running property and a low viscosity that easily flows to every corner of the complicated tread pattern of the mold. . Various methods have hitherto been attempted as a method for obtaining a rubber having a high elastic modulus.
The method of blending a large amount of carbon black is not preferable because the cohesion of rubber in the processing step is poor, the electric power load is increased during kneading and extrusion, and the compound ML becomes large, which causes difficulties during tire molding. . The method of blending a large amount of sulfur has drawbacks such as the plume of sulfur and the crack growth being accelerated due to an increase in crosslink density. When the thermosetting resin is added, since the thermosetting resin has a low compatibility with the normally used natural rubber and diene rubber, it is difficult to obtain a good dispersion when it is added in a large amount. Further, since this kneaded material is hard even when it is not vulcanized, it causes a large load during the kneading / extrusion, and deteriorates the workability of the tire molding. In the method of simply blending the short fibers, the creep is increased or the fatigue life is shortened because the short fibers and the rubber are not sufficiently bonded.

[0005]

DISCLOSURE OF THE INVENTION The present invention uses a rubber composition for a cap tread, which has a high elastic modulus and is excellent in processability, and thus has excellent moldability, high speed running property, wet road surface grasping property and abrasion resistance. The purpose is to obtain a passenger car tire having good properties.

[0006]

The present invention is directed to a fiber reinforced thermoplastic composition, that is, (1) polyolefin ((1) component) (2) vulcanizable rubber ((2) component) (3) main Thermoplastic polymer having amide groups in the chain
(Component (3)), wherein component (1) and component (2) constitute a matrix, and (3) is contained in the matrix.
A composition in which the components are dispersed as fine fibers, and the component (3) is combined with the components (1) and (2), natural rubber, polyisoprene, or a mixture of both (B). ), A diene rubber (C) excluding natural rubber and polyisoprene, and carbon black (D), and a rubber composition satisfying the following conditions (i) to (iv) is used. The present invention relates to a tire for a passenger car, which is used for. (I) The amount of the thermoplastic polymer (1) is 1 to 15 parts by weight based on 100 parts by weight of the total of the rubber component, and (i)
i) The total amount of the natural rubber or polyisoprene in the component (A) and the component (B) in the rubber component is 5 to 40% by weight, and the amount of (iii) carbon black (D) is 60 to 90 parts by weight based on 100 parts by weight in total,
(Iv) The vulcanizate of the composition has a 300% modulus of 100.
It is at least kg / cm ² .

Further, according to the present invention, the fine fibers of the thermoplastic polymer (component (3)) having an amide group in the main chain thereof in the fiber-reinforced thermoplastic composition (A) have 0.05 to 1. 0μ
The present invention relates to a tire for passenger cars, characterized in that a rubber composition having an average diameter of m is used for a cap tread portion.

In the present invention, the polyolefin ((1) component) in the fiber reinforced thermoplastic composition (A) is 50 ° C.
The present invention relates to a tire for a passenger car, characterized in that a rubber composition having the above softening point or a melting point in the range of 80 to 250 ° C is used in a cap tread portion.

Further, in the present invention, the vulcanizable rubber (component (2)) in the fiber-reinforced thermoplastic composition (A) is 10 to 100 parts by weight of polyolefin (component (1)).
The present invention relates to a tire for passenger cars, which comprises using 400 parts by weight of a rubber composition in a cap tread portion.

The rubber composition for a cap tread used in the present invention has a high elastic modulus and a Mooney viscosity ML.
_{Since 1 + 4} (100 ° C) is small and has excellent workability and fluidity, it easily flows to every corner of the complicated tread pattern of the mold.
It also has good wet skid resistance and abrasion resistance.

According to the present invention, there is provided a composition comprising (1) a polyolefin, (2) a vulcanizable rubber, and (3) a thermoplastic polymer having an amide group in its main chain.
The component (1) and the component (2) constitute a matrix, the component (3) is dispersed as fine fibers in the matrix, and the component (3) is the component (1) and the component (2). ) It is essential to blend a fiber-reinforced thermoplastic composition that is bonded to the component, whereby a rubber composition having excellent moldability can be produced despite blending the fibers of the thermoplastic polymer. The composition can be used for a cap tread to produce a tire having good wet road surface graspability and wear resistance.

First, the fiber-reinforced thermoplastic composition of the present invention will be described. This fiber reinforced thermoplastic composition,
(1) Polyolefin, (2) Vulcanizable rubber, and (3) Thermoplastic polymer having an amide group in the main chain are main constituent components, and (1) component and (2) component form a matrix. Most of the component (3) is dispersed as fine fibers in the matrix. Then, the fine short fibers of the component (3) are bonded to the matrix.

The components (1), (2) and (3) of this fiber reinforced thermoplastic composition will be described below. The component (1) is a polyolefin, and is 80-
It has a melting point of 250 ° C. Further, those having a Vicat softening point of 50 ° C. or higher, particularly those having a Vicat softening point of 50 to 200 ° C. are also preferably used.

Examples of such polyolefin include C ₂
To C ₈ olefin homopolymers and copolymers, and C
Of ₂ -C ₈ olefin and styrene or chlorostyrene, alpha
A copolymer with an aromatic vinyl compound such as methylstyrene, a copolymer with a C _{2 to} C ₈ olefin and vinyl acetate, a copolymer with a C _{2 to} C ₈ olefin and acrylic acid or its ester, Copolymers of C _{2 to} C ₈ olefins with methacrylic acid or its esters, and C ₂ to
A copolymer of a C ₈ olefin and a vinylsilane compound is preferably used.

Specifically, for example, high density polyethylene, low density polyethylene, polypropylene, ethylene
Propylene block copolymer, ethylene / propylene random copolymer, linear low density polyethylene, poly-4-methylpentene-1, polybutene-1, polyhexene-
1, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methyl acrylate copolymer,
Ethylene / ethyl acrylate copolymer, ethylene / propyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / 2-ethylhexyl acrylate copolymer, ethylene / hydroxyethyl acrylate copolymer, ethylene / Examples thereof include a vinyltrimethoxysilane copolymer, an ethylene / vinyltriethoxysilane copolymer, an ethylene / vinylsilane copolymer, an ethylene / styrene copolymer, and a propylene / styrene copolymer. or,
Halogenated polyolefins such as chlorinated polyethylene, brominated polyethylene and chlorosulfonated polyethylene are also preferably used. These polyolefins may be used alone or in combination of two or more.

Next, the component (2) will be described.
The component (2) is a vulcanizable rubber, and examples thereof include natural rubber, polyisoprene, polybutadiene, styrene-butadiene rubber, butyl rubber, chlorinated butyl rubber, brominated butyl rubber, and acrylonitrile-butadiene rubber. Of these, natural rubber is preferable. Further, those obtained by subjecting these rubbers to epoxy modification, silane modification, or maleation are also used.

Next, the component (3) will be described.
The component (3) is a thermoplastic polymer having an amide group in the main chain and modified with a silane coupling agent.

Examples of the thermoplastic polymer having an amide group in the main chain include thermoplastic polyamide and urea resin. Of these, the melting point is preferably 135 ° C.
To 350 ° C., and particularly preferable is a thermoplastic polyamide having a melting point of 150 ° C. to 300 ° C.

As the thermoplastic polyamide, nylon 6, nylon 66, nylon 6-nylon 66 copolymer, nylon 610, nylon 612, nylon 46,
Nylon 11, Nylon 12, Nylon MXD6, Polycondensate of xylylenediamine and adipic acid, Polycondensate of xylylenediamine and pimelic acid, Polycondensate of xylylenediamine and speric acid, Xylylenediamine and azelaine Polycondensate with acid, Polycondensate with xylylenediamine and sebacic acid, Polycondensate with tetramethylenediamine and terephthalic acid, Polycondensate with hexamethylenediamine and terephthalic acid, Polycondensation with octamethylenediamine and terephthalic acid Body, polycondensate of trimethylhexamethylenediamine and terephthalic acid, polycondensate of decamethylenediamine and terephthalic acid, polycondensate of undecamethylenediamine and terephthalic acid, polycondensate of dodecamethylenediamine and terephthalic acid, tetramethylene Hexane, a polycondensate of diamine and isophthalic acid Polycondensate of methylenediamine and isophthalic acid, Polycondensate of octamethylenediamine and isophthalic acid, Polycondensate of trimethylhexamethylenediamine and isophthalic acid, Polycondensate of decamethylenediamine and isophthalic acid, Undecamethylenediamine and isophthalic acid Examples thereof include polycondensates of acids and polycondensates of dodecamethylenediamine and isophthalic acid.

Among these thermoplastic polyamides, the most preferable one is a thermoplastic polyamide having a melting point of 160 to 265 ° C., specifically, nylon 6, nylon 66, nylon 6-nylon 66 copolymer, nylon 6
10, nylon 612, nylon 46, nylon 11,
And nylon 12 and the like.

In the thermoplastic composition used in the present invention, the component (1) and the component (2) form a matrix. This matrix may have a structure in which the component (2) is dispersed in the component (1) in an island shape, and conversely, a structure in which the component (1) is dispersed in the component (2) in an island shape. May be taken. The component (1) and the component (2) are preferably bonded to each other at the interface.

Most of the component (3) is dispersed as fine fibers in the matrix. Specifically, 70% by weight, preferably 80% by weight, and particularly preferably 90% by weight or more are dispersed as fine fibers.
The average fiber diameter of the fibers of the component (3) is preferably 1 μm or less, and a particularly preferable range is 0.05 to 0.8 μm.
m. Aspect ratio (fiber length / fiber diameter) is 1
It is preferably 0 or more. And the component (3) is
The matrix composed of the components (1) and (2) is bonded to the interface. This can be confirmed, for example, as follows. First, the fiber-reinforced thermoplastic composition is refluxed in a solvent that dissolves only the components (1) and (2), such as xylene, to remove the components (1) and (2). When the remaining fiber of the component (3) was dissolved in a solvent and the NMR was measured, the components (1) and (2)
The peaks derived from the components can be observed. This is considered to indicate that the component (1) and the component (2) are bound to the surface of the fiber in some form.

The proportions of the component (1), the component (2), and the component (3) are preferably as follows. The component (2) is preferably in the range of 10 to 400 parts by weight, particularly preferably in the range of 20 to 250 parts by weight, and most preferably in the range of 50 to 200 parts by weight, relative to 100 parts by weight of the component (1).
The ratio of the component (2) is 30 with respect to 100 parts by weight of the component (1).
If it is more than 0 parts by weight, only a fiber-reinforced thermoplastic composition which is difficult to pelletize can be obtained, which is not preferable. The ratio of the component (3) is 10 to 40 with respect to 100 parts by weight of the component (1).
It is preferably in the range of 0 parts by weight, particularly 5 to 300
A range of parts by weight is preferred and a range of 10 to 300 parts by weight is most preferred. The ratio of (3) component is (1) component 100
When it exceeds 400 parts by weight, fine fibers of the component (3) are not formed in the fiber-reinforced thermoplastic composition, so that a fiber-reinforced elastic body is produced using such a fiber-reinforced thermoplastic composition. This is because a fiber-reinforced elastic body having high strength cannot be obtained.

The fiber-reinforced thermoplastic composition can be manufactured by the following steps. The fiber-reinforced thermoplastic composition of the present invention comprises the following steps, namely, step 1: a step of preparing a matrix comprising the components (1) and (2), step 2: the component (3) is reacted with a binder. Step, Step 3: A step of melting and kneading the matrix and the component (3) reacted with the binder, Step 4: The obtained kneaded product is extruded at a temperature equal to or higher than the melting point of the component (3), and then It can be produced by a step of stretching and / or rolling at a temperature lower than the melting point of the component (3).

First, the step of preparing a matrix comprising the components (1) and (2) will be described. To prepare a matrix composed of the components (1) and (2),
For example, the component (1) may be first melt-kneaded together with the binder to react, and this may be melted and kneaded with the component (2).
Further, the component (1) and the component (2) are melted together with a binder,
You may knead. The melting and kneading can be performed by an apparatus that is usually used for kneading resins and rubber. As such an apparatus, a Banbury type mixer, a kneader, a kneader extruder, an open roll, a uniaxial kneader,
A biaxial kneader or the like can be used.

The amount of the binder is preferably 0.1 to 2.0 parts by weight, particularly preferably 0.2 to 1.0 part by weight, relative to 100 parts by weight of the component (1). When the amount of the binder is less than 0.1 part by weight, a composition having high strength cannot be obtained, and when it is more than 2.0 parts by weight, a composition having an excellent modulus cannot be obtained.

As the binder, a silane coupling agent,
Titanate coupling agent, novolac type alkylphenol formaldehyde initial condensation product, resol type alkylphenol formaldehyde initial condensation product, novolac type phenolformaldehyde initial condensation product, resole type phenolformaldehyde initial condensation product, unsaturated carboxylic acid and its derivatives, organic peroxides, etc. Any of the commonly used polymer coupling agents can be used. Among these binders, the silane coupling agent is preferable because it hardly gels the component (1) or the component (2) and can form a strong bond at the interface between these components. Examples of the silane coupling agent include vinylalkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris (β-methoxyethoxy) silane, vinyltriacetylsilane, γ-methacryloxypropyltrimethoxysilane, γ- [N- (Β-
Methacryloxyethyl) -N, N-dimethylammonium (chloride)] propylmethoxysilane, styryldiaminosilane, etc., having a group and / or a polar group that easily desorbs a hydrogen atom from other groups such as vinyl group and alkyloxy group. Silane coupling agents are preferably used.

When using a silane coupling agent as a binder, an organic peroxide can be used together. As the organic peroxide, one having a one-minute half-life temperature in the range of the same temperature as the melting point of the component (1) or the melting point of the component (2), whichever is higher, or about 30 ° C. higher than this temperature. It is preferably used. Specifically, the one-minute half-life temperature is 110
Those having a temperature of about 200 ° C. are preferably used. Examples of the organic peroxide include 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane and 1,1-
Di-t-butylperoxycyclohexane, 2,2-di-t-butylperoxybutane, 4,4-di-t-butylperoxyvaleric acid n-butyl ester, 2,2-
Bis (4,4-di-t-butylperoxycyclohexane) propane, 2,2,4-trimethylpentyl peroxyneodecanoate, α-cumyl peroxyneodecanoate, t-butyl peroxyneohexanoate, peroxypivalin T-butyl acid, t-butyl peroxyacetate, t-butyl peroxylaurylate, t-peroxybenzoic acid
-Butyl, t-butyl peroxyisophthalate and the like can be mentioned.

The amount of the organic peroxide used is (1) Component 10
The range of 0.01 to 1.0 parts by weight is preferable with respect to 0 parts by weight.

However, when the components (1) and (2) are melted and kneaded together with a silane coupling agent to modify the silane, the component (2) includes natural rubber and polyisoprene.
Alternatively, when the styrene / isoprene / styrene block copolymer is used, the organic peroxide may not be used.
Rubber having an isoprene structure, such as natural rubber, polyisoprene, and styrene / isoprene / styrene block copolymers, is a type that has a -COO / group at the end of the main chain due to the main chain breaking due to a mechanochemical reaction during kneading. This is because it is considered that the above-mentioned peroxide is generated, and that this acts almost in the same manner as the above-mentioned organic peroxide.

Next, the step of kneading the component (3) with the above matrix will be described. The component (3) may be melt-kneaded with the binder in advance and reacted, and then melt-kneaded with the matrix, or may be melt-kneaded with the matrix in the presence of the binder. Melt kneading can be carried out with an apparatus usually used for kneading resins and rubbers, for example, Banbury type mixer, kneader, kneader extruder, open roll, uniaxial kneader, and biaxial kneader. The same as in the case of preparation.

In the case of the binder for the component (3),
When the total amount of the component (3) and the binder is 100% by weight, the range of 0.1 to 5.5% by weight is preferable, and the range of 0.2 to
A range of 5.5% by weight is particularly preferable, 0.2 to 3% by weight
Is most preferable.

As the binder, a silane coupling agent,
Titanate coupling agent, novolac type alkylphenol formaldehyde initial condensation product, resol type alkylphenol formaldehyde initial condensation product, novolac type phenolformaldehyde initial condensation product, resole type phenolformaldehyde initial condensation product, unsaturated carboxylic acid and its derivatives, organic peroxides, etc. Any of the commonly used polymer coupling agents can be used. Among these binders, the silane coupling agent is the most preferable in that it hardly gels the component (3) and can form a strong bond at the interface with the matrix.

Examples of the silane coupling agent include those having a group capable of forming a bond with the nitrogen atom of the —NHCO— bond of the component (3), such as an alkyloxy group, by a dehydration reaction or a dealcoholization reaction. Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β
-Methoxyethoxy) silane, etc., vinylalkoxysilane, vinyltriacetylsilane, γ-methacryloxypropyltrimethoxysilane, γ- [N- (β-methacryloxyethyl) -N, N-dimethylammonium (chloride)] propylmethoxy Examples thereof include silane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, styryldiaminosilane, and γ-ureidopropyltriethoxysilane.

In this step, the matrix and (3)
The temperature for melting and kneading the components must be at least the melting point of the component (3). Even if melting and kneading are performed at a temperature lower than the melting point of the component (3), the kneaded product does not have a structure in which the fine particles of the component (3) are dispersed in the matrix, and thus the kneaded product is spun. The reason for this is that the component (3) cannot be made into fine fibers even when stretched. The kneading temperature is
It is preferable that the temperature is equal to or higher than the melting point or Vicat softening point of the component (1) polyolefin.

The kneaded material obtained in the above step is extruded from a spinneret, an inflation die or a T die, and then stretched or rolled.

In this step, the fine particles of the component (3) in the kneaded material are transformed into fibers by spinning or extrusion.
This fiber is subjected to a drawing treatment by subsequent drawing or rolling to become a stronger fiber. Therefore, spinning and extrusion must be carried out at a temperature above the melting point of component (3),
Stretching and rolling must be carried out at a temperature lower than the melting point of component (3).

The spinning or extrusion and the subsequent stretching or rolling may be carried out, for example, by extruding the kneaded product from the spinneret, spinning it into a string or thread, and winding it on a bobbin while drafting it. Can be implemented. Here, "drafting" means that the winding speed is higher than the spinning speed. The winding speed / spinning speed ratio (draft ratio) is 1.5 to
The range of 100 is preferable, and the range of 2 to 50 is particularly preferable. The most preferable draft ratio range is 3 to 30.

This step can also be carried out by continuously rolling the spun kneaded product with a rolling roll or the like. Further, the kneaded product can be extruded from an inflation die or a T die and wound on a roll or the like while being drafted. Further, instead of winding a draft while winding it on a roll, it may be rolled by a rolling roll or the like.

The fiber-reinforced thermoplastic composition (A) after stretching or rolling is preferably pelletized. The fiber-reinforced thermoplastic composition is made into pellets, such as natural rubber, polyisoprene or a mixture of both (B), diene rubber (C) excluding natural rubber and polyisoprene, and carbon black (D), This is because they can be kneaded uniformly.

Next, the rubber composition for a cap tread used in the present invention is the above-mentioned fiber reinforced thermoplastic composition (A), natural rubber, polyisoprene or a mixture of both (B), natural rubber and polyisoprene. Except for diene rubber (C) and carbon black (D).

Examples of the diene rubber (C) include polybutadiene, styrene-butadiene copolymer rubber, isoprene-isobutylene copolymer and the like. As the carbon black (D), those having a particle size of 90 mμ or less and a dibutyl phthalate (DBP) oil absorption amount of 70 ml / 100 g or more are preferably used. Examples of carbon black include FEF, FF, GPF, SAF, ISAF,
Various carbon blacks such as SRF and HAF are used.

In each of the above components, (i) the amount of the thermoplastic polymer (component (3)) is 1 to 15 parts by weight based on 100 parts by weight of the total of the rubber components, and (ii) the rubber component,
The total amount of the natural rubber or polyisoprene in the component (A) and the component (B) is 5 to 40% by weight, and the amount of the carbon black (D) (iii) is 100 parts by weight based on 100 parts by weight of the total rubber component. It is 60 to 90 parts by weight, and the vulcanized product of (iv) composition is blended so as to satisfy each condition that the 300% modulus defined by JIS K6301 is 100 kg / cm ² or more.

When the amount of the thermoplastic polymer is less than the lower limit, a composition having a large elastic modulus of a vulcanized product cannot be obtained,
When the amount of the thermoplastic polymer is more than the above upper limit, the ML of the composition becomes too large and the Mooney viscosity becomes too large, resulting in poor moldability. If the amount of carbon black is less than the lower limit, the elastic modulus of the vulcanizate will decrease, while if it is greater than the upper limit, the Mooney viscosity will tend to be too high and tire moldability will tend to deteriorate. On the other hand, if the proportion of the rubber is out of the above range, the vulcanized product has poor pico-abrasiveness and wet skid resistance.

The rubber composition for a cap tread of the present invention can be obtained by mixing the above components using a kneading machine such as a Banbury mixer, a kneader, an open roll, and a twin-screw kneader. The kneading temperature needs to be lower than the melting point of the thermoplastic polymer that constitutes the fine short fibers in the fiber-reinforced thermoplastic composition. Kneading at a temperature higher than the melting point of this thermoplastic polymer is not preferable because the fine short fibers in the fiber-reinforced thermoplastic composition are melted and transformed into spherical particles or the like.

Further, the fiber-reinforced thermoplastic composition is preferably pelletized. When the pellet-shaped fiber-reinforced thermoplastic composition is used, the fiber-reinforced thermoplastic composition (A) can be uniformly kneaded with the components (B), (C) and (D), and fine fibers are uniformly dispersed. This is because the rubber composition for cap tread can be easily obtained.

Additives such as a vulcanizing agent are added to the rubber composition of the present invention. As the vulcanizing agent, known vulcanizing agents such as sulfur, organic peroxides, and sulfur-containing compounds can be used. The method of compounding the vulcanizing agent with the rubber composition is not particularly limited, and a compounding method known per se can be adopted. Along with vulcanizing agents, white carbon, activated calcium carbonate, ultrafine magnesium silicate, high styrene resin, coumarone indene resin, phenol resin, lignin, modified melamine resin, petroleum resin and other reinforcing agents, various grades of calcium carbonate, Basic magnesium carbonate, clay, zinc white, diatomaceous earth, recycled rubber,
Powder rubber, fillers such as ebonite powder, aldehydes, ammonias, aldehydes / amines, guanidines, thioureas, thiazoles, thiurams, dithiocarbamates, xanthates and other vulcanization accelerators, metal oxides, fatty acids Vulcanization accelerating aids such as amines and aldehydes,
Amine / ketones, amines, phenols, imidazoles, sulfur-containing or phosphorus-containing antioxidants, naphthene-based or aromatic process oils, etc. are blended within a range that does not impair the effects of the present invention. Can be prepared.

The vulcanization temperature of the rubber composition of the present invention is 100-.
About 190 ° C is preferable. However, the vulcanization temperature needs to be lower than the melting point of the thermoplastic resin forming the fine fibers in the rubber composition. When vulcanization is performed at a temperature equal to or higher than the melting point of the thermoplastic resin, the fibers formed in the stage of preparing the bent-angle fiber-reinforced thermoplastic composition are melted, and the processability is excellent, and the rubber having good physical properties of the vulcanized product is obtained. This is because the composition cannot be obtained.

The passenger car tire of the present invention is combined with the above-described rubber composition for cap tread and other tire members (base tread, sidewall, carcass, belt, bead, etc.) by a method known per se. It can be manufactured.

[0050]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. In Examples and Comparative Examples,
The observation of the dispersion shape of ((3) component) in the fiber reinforced thermoplastic composition, and the Mooney viscosity, the tensile elastic modulus, the pico abrasion and the wet skid resistance of the obtained rubber composition for a cap tread are as follows. Measured.

(1) (3) in the fiber-reinforced thermoplastic composition
Observation of dispersion form of components: Pellets of each sample were mixed with a mixed solvent of o-dichlorobenzene and xylene (volume ratio 50: 5).
The mixture was refluxed in 0) at 100 ° C. to extract and remove the polyolefin and elastomer therein, and the remaining fibers were observed with an electron microscope. (2) Mooney viscosity According to JIS K6300, Mooney viscosity M at 100 ° C.
L _{1 + 4} was measured. (3) Tensile Elastic Modulus The tensile elastic modulus M ₃₀₀ was measured according to JIS K6301. (4) Pico abrasion The pico abrasion index was measured according to ASTM D2228. (5) Wet skid resistance A portable wet skid tester was used and measurement was performed using a safety walk (Type B) manufactured by 3M.

[Sample 1] As component (1), polypropylene (Ube Polypro JI0 manufactured by Ube Industries, Ltd.)
9, melting point 165 to 170 ° C., melt flow index 9 g / 10 min), and natural rubber (N) as component (2)
R, SMR-L) as component (3), nylon 6 (manufactured by Ube Industries, Ube nylon 1030B, melting point 21)
5 to 220 ° C. and a molecular weight of 30,000) were used. (1)
The components are 0.5 parts by weight of γ-methacryloxypropyltrimethoxysilane and 0.1 parts by weight of 4,4-di-t-butylperoxyvaleric acid n based on 100 parts by weight of the component (1). -Modified by melt-kneading with butyl ether. The component (3) was modified by melt-kneading with 1.0 part by weight of N-β (aminoethyl) γ-aminopropyltrimethoxysilane with respect to 100 parts by weight of the component (3).

First, 100 parts by weight of the component (1) modified as described above was kneaded with 100 parts by weight of the component (2) in a Banbury type mixer to prepare a matrix. This was dumped at 170 ° C. and pelletized. Next, this matrix and 100 parts by weight of the component (3) were kneaded with a biaxial kneader heated to 240 ° C. to pelletize the kneaded product. The obtained kneaded product was extruded in a string shape by a uniaxial extruder set at 245 ° C., and pelletized by a pelletizer while being taken at a draft ratio of 10. The obtained pellets were refluxed in a mixed solvent of o-dichlorobenzene and xylene to remove polyolefin and NR, and the shape and diameter of the remaining fibers were observed with an electron microscope. It was confirmed that it was a fiber.

[Sample 2] Sample 2 was prepared in the same manner as in Sample 1, except that the proportion of nylon 6 as the component (3) was increased to 200 parts by weight relative to 100 parts by weight of the polypropylene as the component (1). , This was pelletized. The obtained pellets were refluxed in a mixed solvent of o-dichlorobenzene and xylene to remove polyolefin and NR, and the shape and diameter of the remaining fibers were observed with an electron microscope. It was confirmed that it was a fiber.

[Sample 3] Sample 1 except that the polypropylene as the component (1) was 100 parts by weight, the natural rubber as the component (2) was 75 parts by weight, and the nylon 6 as the component (3) was 87.5 parts by weight. Sample 3 was prepared in the same manner as in 1. and pelletized. The obtained pellets were refluxed in a mixed solvent of o-dichlorobenzene and xylene to remove polyolefin and NR, and the shape and diameter of the remaining fibers were observed with an electron microscope. It was confirmed that it was a fiber. Table 1 shows the ratio of each component of Samples 1 to 3 and the shape of the nylon 6 fiber.

Example 1 A B-type Banbury (volume: 1.7 liters) set at 100 ° C. and 77 rpm was used, and Sample 1 was used as the fiber-reinforced thermoplastic composition. A compounding agent other than the accelerator and sulfur was kneaded to obtain a kneaded product which was a rubber composition for a cap tread. At this time, the maximum kneading temperature was adjusted to 170 to 180 ° C. Next, this kneaded product was kneaded with a vulcanization accelerator and sulfur on a 10-inch roll, rolled out into a sheet, and then placed in a mold for vulcanization to obtain a vulcanized product. Vulcanization is
It was carried out at 145 ° C. for 40 minutes. The results are summarized in Table 2.

[Examples 2 and 3] A rubber composition for a cap tread was obtained in the same manner as in Example 1 except that the fiber-reinforced thermoplastic composition used was changed to the samples shown in Table 2. The results are summarized in Table 2.

[Examples 4 and 5] Table 2 shows the blending ratio of each component.
A rubber composition for a cap tread was obtained in the same manner as in Example 1 except that the rubber composition was changed as shown in FIG. The results are summarized in Table 2.

[Examples 6 to 9] The same procedure as in Example 1 was carried out except that the kind of carbon black to be blended was changed. The results are summarized in Table 2.

[Comparative Examples 1 and 2] A rubber composition for a cap tread was prepared in the same manner as in Example 1 except that the ratio of each component was changed as shown in Table 2 without using the fiber reinforced thermoplastic composition. Obtained. The results are summarized in Table 2.

[0061]

[Table 1]

[0062]

[Table 2]

(Note 1) BR: polybutadiene (UBEP
OL-BR153A, manufactured by Ube Industries, Ltd. (Note 2) N-110: SAF, particle diameter 18 mμ, DB
P oil absorption 115ml / 100g N-220: ISAF, particle size 21mμ, DBP oil absorption
117ml / 100g N-330: HAF, particle size 30mμ, DBP oil absorption
110ml / 100g N-440: FF, particle size 3
8mμ, DBP oil absorption 75ml / 100g N-55
0: FEF, particle size 41mμ, DBP oil absorption 122ml / 1
00g (Note 3) Other compounding agents Zinc white: 3 parts, stearic acid: 2 parts, anti-aging agent N-
Phenyl-N'-isopropyl-p-phenylenediamine: 1 part, vulcanization accelerator N-oxydiethylenebenzothiazyl-2-sulfenamide: 0.8 part, sulfur:
1.7 copies

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Claims (4)

[Claims] 1. A fiber reinforced thermoplastic composition, that is, (1) polyolefin (hereinafter referred to as (1) component) (2) vulcanizable rubber (hereinafter referred to as (2) component) (3) main chain Thermoplastic Polymer Having Amido Group
(Hereinafter, referred to as (3) component), wherein the (1) component and the (2) component form a matrix, and the (3) is contained in the matrix.
A composition in which the components are dispersed as fine fibers, and the component (3) is combined with the components (1) and (2), natural rubber, polyisoprene, or a mixture of both (B). ), A diene rubber (C) excluding natural rubber and polyisoprene, and carbon black (D), and a rubber composition satisfying the following conditions (i) to (iv) is used. A passenger car tire characterized by being used for. (I) The amount of the thermoplastic polymer (3) is 1 to 15 parts by weight based on 100 parts by weight of the total rubber component, (ii) the natural rubber or polyisoprene in the component (A) in the rubber component. And the total amount of the component (B) is 5 to 40% by weight.
And (iii) the amount of carbon black (D) is 60 to 90 parts by weight based on 100 parts by weight of the total of the rubber components, and (iv) the vulcanized product has a 300% modulus of 100.
It is at least kg / cm ² . 2. Fine fibers of a thermoplastic polymer (component (3)) having an amide group in its main chain in the fiber-reinforced thermoplastic composition (A) have an average diameter of 0.05 to 1.0 μm. The tire for a passenger car according to claim 1, further comprising: 3. The polyolefin (component (1)) in the fiber-reinforced thermoplastic composition (A) has a softening point of 50 ° C. or higher or a melting point in the range of 80 to 250 ° C.
Alternatively, the passenger car tire according to claim 2. 4. The vulcanizable rubber (component (2)) in the fiber-reinforced thermoplastic composition (A) is 10 to 400 parts by weight based on 100 parts by weight of the polyolefin (component (1)). The tire for passenger cars according to any one of claims 1 to 3.