JPS6381137A - Reinforced rubber composition and production thereof - Google Patents

Abstract

PURPOSE:To obtain a composition, by kneading and extruding a vulcanizable rubber, fine and short polyamide fibers and silane coupling agent at a temperature above the melting point of the above-mentioned polyamide and having improved strength, modulus as well as crack growth resistance of vulcanizates. CONSTITUTION:A composition produced by blending (A) 100pts.wt. vulcanizable rubber, preferably natural rubber, polyisoprene, isoprene-isobutylene copolymer with (B) 1-100pts.wt., preferably 1-70pts.wt. fine and short fibers of a polyamide having 150-260 deg.C melting point, >=5,000 number-average molecular weight 0.05-0.8mu average diameter and >=1mu shortest fiber length and (C) a silane coupling agent, e.g. gamma-aminopropyltrimethoxysilane, etc., in an amount of 0.1-5.5 pts.wt., preferably 0.2-5pts.wt. based on 100pts.wt. component (B), melt kneading the resultant blend at a temperature above the melting point of the component (B) and extruding the kneaded blend at a temperature above the melting point of the component (B).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for manufacturing rubber-filled lead-on top metals that are superior in productivity and processability, as well as in the modulus, strength, and crack growth resistance of vulcanizates. This is related to the first notice↓.

[Industrial Application Fields] The reinforced rubber composition of the present invention can be used in tire internal parts such as belts, carcass, and beads, tire external parts such as treads and sidewalls, belts, hoses, etc. by utilizing its excellent properties. It can be used for industrial products, footwear materials, etc.

[Prior Art] Conventionally, reinforced rubber compositions used for various parts of tires are
It is manufactured by blending mtam such as nylon, polyester, vinylon, etc. with vulcanizable rubber. However, the reinforced rubber composition obtained in this way has a large fiber diameter and a bond between the fiber and rubber. Therefore, the modulus and strength of the vulcanizate, especially the modulus and strength at high elongation, are insufficient, and it is desired to develop a reinforced rubber composition that provides a vulcanizate with even more excellent modulus and strength. .

Therefore, an elastomer strengthening method and a reinforced elastomer composition were proposed in which a polymer having fiber-forming ability and rubber were kneaded and the kneaded product was then extruded (JP-A-53-86
However, even with this method, thick fibers or films of the polymer are produced, and since there is no bond between the rubber on the #a male surface and the polymer (fiber), the tensile strength of the vulcanizate is The strength, modulus at high elongation, and peel strength, which indicates adhesion to other types of base materials, are low, making it impossible to obtain a reinforced rubber composition that can be used as a tire member.

Japanese Patent Publication No. 55-41652 describes a method for producing a reinforced rubber composition by kneading vulcanizable rubber and powdered 1,2-polybutadiene, extruding the kneaded mixture, and then rolling it with rolls. ing.

In the reinforced rubber composition obtained by this method, the vulcanizate exhibits high elasticity, high elongation, high strength, and high peel strength.
．． Because the strength of the m-fibers formed from 2-polybutadiene is low, the ia-fibers are cut during rubber processing, especially during carbon blurring and kneading, and the ta-fiber length becomes short, resulting in low elongation of the vulcanizate. It has the disadvantage of low stress.

Therefore, in order to improve the drawbacks of conventionally known reinforced rubber compositions, the present inventors melt-extruded a composition in which a block copolymer of liquid diene rubber and nylon was blended into vulcanizable rubber. proposed a method for producing a reinforced rubber composition in which nylon is made into fibers and vulcanizable rubber and liquid diene rubber are grafted together (Japanese Patent Laid-Open No. 58-193).
No. 42), however, this production method had problems in practice because the reproducibility of block polymerization was not very good and the cost was high.

Furthermore, in order to improve this drawback, the present inventor embedded fine polyamide fibers in vulcanizable rubber and
We proposed a reinforced rubber composition in which vulcanizable rubber and iam are graft-bonded via an initial condensate of phenol formaldehyde at the a-fiber interface (Japanese Patent Laid-Open No. 1865-1865).
No. 50).

However, this reinforced rubber composition has excellent productivity and processability, and provides a vulcanizate with excellent modulus, tensile strength, and adhesion at low and high elongations, but it has poor crack growth resistance. The drawbacks have severely limited its use.

[Problems to be Solved by the Invention] The present invention solves the drawbacks of low productivity and crack growth resistance of the prior art, has excellent productivity and processability, and also has low elongation and Modulus at high elongation.

It is an object of the present invention to provide a reinforced rubber composition having excellent tensile strength, particularly crack growth resistance, and a method for producing the same.

[Means for Solving the Problems] The present invention is characterized in that 1 to 100 parts by weight of fine short ta fibers of polyamide which can be formed into fibers are embedded in 100 parts by weight of vulcanizable rubber, and the polyamide and the rubber This problem is solved by using a reinforced rubber composition characterized in that these are bonded together via a silane coupling agent.

The reinforced rubber composition of the present invention has excellent productivity and processability, and also has excellent modulus, tensile strength, and adhesion at low elongation and high elongation in vulcanized products, and has excellent crack growth resistance. ing.

As the vulcanizable rubber in this invention, all rubbers that give a rubber elastic body by vulcanization can be used, such as natural rubber, cis-1,4-polybutadiene, polyisoprene, polychloroprene, Mention may be made of styrene-butadiene copolymer rubber, isoprene-isobutylene copolymer, ethylene-propylene-nonconjugated diene terpolymer and mixtures thereof.

Among these rubbers, melt vulcanizable rubbers and mixtures of polyamides and silane coupling agents.

Particularly preferred are natural rubber, polyisoprene, and isoprene-isobutylene copolymers, which hardly gel when kneaded and then extruded.

In the present invention, polyamides capable of forming la-ga shadows include nylon 6, nylon 6/66, nylon 6/10, nylon 12, nylon 6/11, nylon 6/12, nylon 66, etc., and their melting points are 150 to 260. ℃, preferably 180 to 235℃.

The polyamide is not particularly limited as long as it has fiber-forming ability, but it has a number average molecular weight of 5,000 or more, preferably 8
,000 or more, if the molecular weight is too low, the fa fiber forming ability is poor and the strength is also low.

In the reinforced rubber composition of the present invention, the proportion of fine short polyamide fibers embedded in the vulcanizable rubber is 1 to 100 parts by weight, preferably 1 to 100 parts by weight of the fibers per 100 parts by weight of the vulcanizable rubber. 1 to 70 parts by weight, particularly preferably 30 to 70 parts by weight
It is 70 parts by weight.

If the proportion of fibers embedded in the vulcanizable rubber is less than the lower limit, the strength and modulus of the vulcanizate will not be improved, and the proportion of fibers embedded in the vulcanizable rubber will be lower than the lower limit. When the amount is more than the upper limit, crack growth resistance decreases.

In addition, the average diameter of the fine short polyamide fibers is 0.05
~0.8 l, and the shortest fiber length of the circular cross section is preferably 1 l or more, m! It is embedded in vulcanizable rubber in the form of fine short fibers with molecules arranged in the a-axis direction.

Furthermore, at the interface of the TA fibers, the polyamide and the vulcanizable rubber are bonded via a silane coupling agent.

The silane coupling agent in the present invention has the structural formula Y
-RISiX3 is a compound represented by Y-R1SiR2X2.

Here, Y, R1, R2, and X each represent the following groups.

H3-C6H5- R1: ApCnH2nB□CmH2mBqC5H2
IA: C6H4p=o~2 n=o~5 B: O,NHQ-0~2 Otori=0~5! L; 0~5 R2: Cn H2n◆1 n = 1~4
X: Dr Cn H2n Es Cm H2m+
1D: O, CJL r = o ~ 2n snow 0 ~ 5 E: Os = 1 ~ 2 proverb = 1 ~ 5 Specifically, γ-7 minoprobyl trimethoxysilane, γ
-aminopropyltriethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-
β(aminoethyl)γ-7minopropylmethyldimethoxysilane, γ-(diethylenetriamino)propyltrimethoxysilane, γ-ureidopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(βmethoxyethoxysilane) ) silane, γ-glycidoxypropylmethyljethoxysilane,
γ-glycidoxypropyltrimethoxysilane, β-(
3,4 epoxycyclohexyl)ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N-phenyl-γ-
Aminopropyltriethoxysilane, N-β (N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, and the like can be suitably used.

Further, the amount of the silane coupling agent used in the present invention is 0.00 parts by weight per 100 parts by weight of the fiber-formable polyamide.
The amount is 1 to 5.5 parts by weight, preferably 0.2 to 5 parts by weight.

If the amount of the silane coupling agent is less than the lower limit, the reaction between the vulcanizable rubber and the polyamide through the silane coupling agent is difficult to occur, and therefore a thick tam or film of the polyamide is not formed. Furthermore, since the bond between the polyamide and the rubber at the fiber interface is weak, the strength and crack growth resistance of the vulcanizate obtained by vulcanizing this reinforced rubber composition are reduced. Furthermore, if the amount of the silane coupling agent is more than the above upper limit, the silane coupling agent causes gelation of the vulcanizable rubber, which prevents the formation of TA fibers in the polyamide. The resulting vulcanizate is strengthened and its modulus decreases.

The method for producing the composition of the present invention involves combining a vulcanizable rubber, a fiber-forming polyamide, and 0.1 to 5.5 parts by weight of a silane coupling agent per 100 parts by weight of the polyamide at a temperature equal to or higher than the melting point of the polyamide. By kneading at a temperature and extruding the obtained kneaded product at a temperature higher than the melting point of the polyamide, or appropriately stretching the extrudate at a temperature higher than the melting point of the polyamide, or stretching the extrudate at a temperature lower than the melting point, or by stretching these. Provided by using in combination.

The method for producing the reinforced rubber composition of the present invention is to tri-blend a predetermined amount of vulcanizable rubber, polyamide, and silane coupling agent, and melt-knead the mixture at a temperature higher than the melting point of polyamide, which can be vulcanized. 100 parts by weight of rubber, 1 to 100 parts by weight of polyamide, and 100 parts of polyamide
A kneaded material containing 0.1 to 5.5 parts by weight of the silane coupling agent per part by weight can be obtained. Further, by melt-kneading vulcanizable rubber or polyamide and a silane coupling agent and adding or melt-kneading polyamide or vulcanizable rubber to this kneaded product, 100 parts by weight of vulcanizable rubber,
1 to 100 parts by weight of polyamide and 100T polyamide
A kneaded material containing 0.1 to 5.5 parts by weight of the silane coupling agent per part of fLik can be obtained.

Further, using the above kneaded product as a master, polyamide or vulcanizable rubber was added to the kneaded product to prepare 100 parts by weight of vulcanizable rubber, 100 parts by weight of polyamide 1N, and polyamide 1N.
A kneaded material containing 0.1 to 5.5 parts by weight of the silane coupling agent per 00 parts by weight can be obtained.

The above-mentioned mixing of each component is preferably carried out for 1 to 15 minutes using a Brabender blastograph, Banbury mixer, roll, extruder, or the like.

- In the method of this invention, an anti-aging agent, such as N-(3-methacryloyloxy-2 -hydroxypropyl)-N' -phenyl-p-phenylenediamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine, N,N'
-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N
-cyclohexyl-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-α-dimethylamino-p-
Cresol, 2.2°-dihydroxy-3,3°-bis(α-methylcyclohexyl)-5,5°-dimethyl.
It is preferable to incorporate a low volatility anti-aging agent such as diphenylmethane.

Next, the obtained kneaded part is melt-extruded at a temperature higher than the melting point of the polyamide, preferably 5°C higher than the melting point, and lower than 270°C, or stretched or stretched at a temperature higher than the melting point of the polyamide as appropriate. A reinforced rubber composition can be obtained by stretching at a lower temperature or by using these stretching in combination. At this time, production of the kneaded material, melt extrusion, and stretching can also be performed in one step.

Specifically, when using a goo with a circular or rectangular discharge opening, such as a circular die that can extrude in the form of a string (or sheet) through a circular goo or a rectangular die, the inner diameter of the discharge opening ga n INC' + wll out ro small 7 g out of the exit (L/D) is 1~20
When using a rectangular die, the slit gap is preferably 0.1 to 5 mm and the width is 0.2 to 200 mm.
It is preferable that the length of the guiland is 10 to 205 m.

Among the above-mentioned various dies, it is preferable to use a circular die.As the zero-circular gouie, one having one discharge port or one having a large number of discharge ports (multi-hold type) can be used.

For extrusion of the kneaded product, a known extruder such as a screw extruder is used, the temperature at the tip of the screw is set to a temperature above the melting point of the polyamide and below 270°C, and the temperature of the die is set above the melting point of the polyamide. and 270°C or less, especially 5°C or more higher than the melting point of the polyamide and 2
It is preferable to extrude the kneaded material at a temperature of 60° C. or lower.

In the method of the present invention, by extruding the kneaded product as described above, the polyamide in the vulcanizable rubber of the extrudate obtained has an m-male shape, and the polyamide is formed at the interface between the ta-fibrous polyamide. and a vulcanizable rubber are combined via a silane coupling agent.

The reinforced rubber composition of this invention comprises the above-mentioned extrudate.

At a temperature above the melting point of the polyamide, preferably under continuous tension, by a method known per se, a winding machine (drawing machine) such as a bobbin or a winding roll is applied at a speed of 1 to 100 m/min, preferably 20 to 4 m/min. Stretched at a winding speed of 0 m/min, air cooled,
Cooling to a temperature below the melting point of the polyamide by water cooling, cooling with an organic solvent (inert to rubber and polyamides such as chilled methanol), or by increasing the distance from the gouer to the winder (also called drawing machine) After that, it can be obtained by stretching using a pair of rolling rolls at a temperature below the melting point of the polyamide, or by uniaxially stretching using a stretching roll. The temperature of the winder (stretching machine) when winding up the extrudate is preferably 0 to 100°C.If the extrudate touches the surface of the winder (stretching machine) at a temperature higher than the melting point of the polyamide, part of the fibrous polyamide will melt. becomes flat (in extreme cases, film-like), and a good reinforced rubber composition may not be obtained. The temperature of the stretching using the rolling rolls is preferably 0-100°C.

It is preferable that the stretching using the stretching rolls be performed at a stretching ratio of 1.1 to 10.

In the method of the present invention, the polyamide in the vulcanizable rubber of the resulting reinforced rubber composition is obtained by stretching the extrudate to a temperature above the melting point of the polyamide, below the melting point, or in combination with the above-mentioned stretching. The fibers undergo molecular orientation and transform into a fibrous structure, becoming fine, short fibers with great strength.

The reinforced rubber composition obtained by the method of the present invention contains 1 to 100 parts by weight of a fiber-formable polyamide per 100 parts by weight of vulcanizable rubber, the polyamide is a fine short taIII, and the fibers are Polyamide and vulcanizable rubber are bonded via a silane coupling agent at the interface of It is possible to provide a vulcanizate with excellent modulus, tensile strength, and crack growth resistance.

In addition, in the reinforced rubber composition of the present invention, the vulcanizate bonded to the polyamide via the silane coupling agent at the interface of the polyamide fine short fibers embedded in the vulcanizable rubber is Weight percentage of vulcanizable rubber (vulcanizable rubber/polyamide fine short m fibers)
The amount of bonded rubber represented by is 10 to 30% by weight, especially 15 to 30% by weight.
It is preferable that the polyamide forming the m-fiber and the vulcanizable rubber are bonded together via a silane coupling agent such that the amount is 30% by weight.

The reinforced rubber composition of the present invention utilizes its excellent properties to improve tire internal parts such as belts, carcass, beads, etc.
It can be used for tire external parts such as treads and sidewalls, industrial products such as belts and holes, and footwear materials.

[Effects of the present invention] The composition of the present invention has fine short polyamide fibers embedded in vulcanizable rubber, and the vulcanizable rubber and polyamide are bonded via a silane coupling agent. As a result, a new rubber-reinforced composition with excellent strength, modulus and crack growth resistance of the vulcanizate can be obtained. This composition also has excellent productivity and processability.

[Example of the present invention] Next, examples, comparative examples, and reference examples will be shown.

Obtained in Examples, Comparative Examples and Reference Examples (strengthening)
The physical properties of the vulcanizate were tested in accordance with JIS K8301 to evaluate the rubber composition.

Example 1 100 parts of natural rubber (NR) with a melt viscosity of lXl06 bois was placed in a Gravender plastograph set at 220°C, 50r, p, and 100 parts of natural rubber (NR) was added as an anti-aging agent.
3-methacryloyloxy-2-hydroxypropyl)
-N'-Phenyl-p-phenylenediamine [TSKURAK G-1, Ohmukai Shinko Kagaku Kogyo ■] was added,
After stripping for 30 seconds, nylon 6 (trade name 1030B, manufactured by Ube Industries, melting point 221'0, molecular weight 30,000) 10
2 parts by weight per 0 parts by weight of N-β(aminoethyl)γ-aminopropyltrimethoxysilane (trade name KMB 60
3, manufactured by Shin-Etsu Chemical Co., Ltd. (hereinafter referred to as silane A), were added thereto and kneaded for 13 minutes (during which time the temperature inside the Brabender rose to 230° C.) to obtain a kneaded product. The obtained kneaded material was poured into a nozzle with an inner diameter of 2 cm.
■Using a 20mmφ extrusion Ia (manufactured by Haake) with a circular die with a length-to-inner diameter ratio (L/D) of 2, extrude it into a string shape at a set temperature of 235°C, and then extrude the object directly below the nozzle. It was wound onto a bobbin at a draft ratio of 10 (speed of 38.8 m/min) through a guide roll installed at a height of 3 m. Approximately 500 of these rolls were bundled into a sheet (approximately 2 mm thick and approximately 150 mm wide).

This sheet-like material was roll-stretched to about 0 times by a pair of rolling rolls with a roll gap of 0.2 mm and a temperature of 60° C. to obtain a master batch of 1 reinforced rubber composition.

Rubber.

2 g of the reinforced rubber composition obtained in Example 1 was mixed with 20 g of toluene.
The slurry was added at 80° C. at 0 m to dissolve the rubber component in the reinforced rubber composition, and the resulting slurry was centrifuged at room temperature to separate it into a solution portion and a precipitate portion. After repeating the above operation seven times for the precipitated portion, the precipitated portion was dried to obtain a male nylon fiber. Dissolve this nylon fiber in a mixed solvent of phenol and orthodichlorobenzene! H
Analyzed by nuclear magnetic resonance spectroscopy (NMR) (internal standard: tetramethylsilane), the NMR chart showed methyl and methylene groups originating from the colored rubber, and carbon originating from the nylon fiber.
For each peak of the methylene group adjacent to the O group, the methylene group adjacent to the NH group, and the other three methylene groups, the molar ratio of nylon to rubber was determined by the cut area method, and the amount of bonded rubber was calculated. . Further, the shape of the nylon fibers was measured using a scanning microscope at a magnification of 1,000 times for about 200 fibers. One fiber was an extremely thin short tassel with a circular cross section. The results are summarized in Table 1.

1iS1 The reinforced rubber composition obtained in Example 1 was vulcanized at 145° C. for 30 minutes according to the formulation shown in Table 2, and its physical properties were measured. The results are shown in Table 2.

Example 2 A 30 mm φ-shaft extruder set at 240°C (L/D=2
6) Natural rubber (N R) with a melt viscosity of 5 x 105 voids, N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylenediamine as an antiaging agent, and The nylon pellets kneaded with Silane A used in Example 1 were mixed with natural rubber, N)-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylenediamine, and the nylon pellets in a ratio of Zoo. /1151 and extruded at a rate of 2 Kg/hr to obtain a kneaded product. The subsequent operations were carried out in the same manner as in Example 1.

The results are summarized in Tables 1 and 2.

Example 3 In a butibender plastograph set at 220° C., 50 r, p, m, a viscosity of 1×lO6 bois rr+
1 lkgo I-(NQ) 1 n nHt-kklX4!
-Nok Kh +L- was mixed and 1.0 part of N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylenediamine was added, and after masticating for 30 seconds, 6-nylon (Product name 1030B, manufactured by Ube Industries) and 1 part by weight of Silane A were added.
The mixture was kneaded for 3 minutes to obtain a kneaded product. The subsequent operations were carried out in the same manner as in Example 1.

The results are summarized in Tables 1 and 2.

Example 4 N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane (trade name KBM502,
The same procedure as in Example 1 was conducted except that Silane B (manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter referred to as B) was used.

The results are summarized in Tables 1 and 2.

Example 5 Vinyltris (βmethoxyethoxy) in place of Silane A
The same procedure as in Example 1 was carried out except that silane (trade name KBM1003, manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter referred to as Silane C) was used.

The results are summarized in Tables 1 and 2.

Example 6 The same procedure as in Example 1 was carried out except that γ-methacryloxypropyltrimethoxysilane (trade name KBM503, manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter referred to as silane D) was used in place of silane A.

The results are summarized in Tables 1 and 2.

Example 7 In the same manner as in Example 1, γ-mercaptopropyltrimethoxysilane (trade name KBM803, manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter referred to as Sila 7E) was used in place of Silane A. carried out.

The results are summarized in Tables 1 and 2.

Example 8 Silane A was replaced with β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (trade name KBM303.
The same procedure as in Example 1 was carried out except that Silane F (manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter referred to as F) was used.

The results are summarized in Tables 1 and 2.

Example 9 The same procedure as in Example 1 was carried out, except that γ-chloropropyltrimethoxysilane (trade name KBM703, manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter referred to as silane G) was used in place of silane A.

The results are summarized in Tables 1 and 2.

Example 10 In place of Silane A, N-β(N-vinylbenzylaminoethyl)-γ-7minoprobyltrimethoxysilane hydrochloride (trade name 5Z-6032, Torayashi results are summarized in Tables 1 and 2) Shown in the table.

Comparative Example 1 100 parts of natural rubber (NR) having a viscosity of 1 x 106 voids and N-(3-methacryloyloxy-2-hydroxypropyl -P-phenylenediamine was added, and after masticating for 30 seconds, 6-nylon (1030
B) 50 parts were added and kneaded for 4.5 minutes, then 2.25 parts of novolac type phenol formaldehyde initial condensate (trade name 550PL, manufactured by Meiso Kasei ■) were added and kneaded for 3 minutes, and then hexamethylene radramine was added. 0.225 part was added and kneaded for 3.5 minutes to obtain a kneaded product. The subsequent operations were carried out in the same manner as in Example 1.

The results are summarized in Tables 1 and 2.

Example 11 The results of Example 1 are summarized in Tables 1 and 2, except that polyisoprene (Kuraprene IR-10) was used instead of natural rubber (NR).

Example 12 Example 1 except that inbrene-inbutylene copolymer (Essoptylene 365) was used instead of natural rubber (NR).
It was carried out in the same way.

The results are summarized in Tables 1 and 2.

Example 13 Cis 1,4-polybutyl 11 plast in a Gravender Plastograph set at 200°C and 50 r, p, m.
-ノ t ま Tfll de D eight cho Of
) 100 copies of N-(
3-methacryloyloxy-2-hydroxypropyl)
-N'-Phenyl-p-phenylenediamine [TSKURAK G-1, Ohmukai Shinko Kagaku Kogyo ■] was added,
After stripping for 30 seconds, 51 parts of pellets pre-mixed with 2 parts by weight of Silane A were added to 100 parts by weight of nylon 12 (trade name 3035U, manufactured by Ube Industries, Ltd., melting point 176°C), and kneaded for 10 minutes. During this time, the temperature inside the plastic bender rose to 205° C.) A kneaded product was obtained. The obtained kneaded material was heated by 2 parts of the inner diameter of the nozzle, and the length to inner diameter ratio (L/D) was 2 parts.
Using a 20+sφ extruder (manufactured by Haake) having a circular die, the mixture was extruded into a string shape at a temperature set at 220° C., and the following operations were performed in the same manner as in Example 1.

The results are summarized in Tables 1 and 2.

Example 14 Nylon 6 (trade name 1013B, manufactured by Ube Industries, melting point 2)
Example 1 was carried out in the same manner as in Example 1, except that 52 parts of pellets in which 4 parts by weight of Silane A per 100 parts by weight (21'0, molecular weight 13,000) were mixed in advance were used.

The results are summarized in Table 1 and Table t52.

Example 15 The same procedure as in Example 1 was carried out except that 30.6 parts of nylon kneaded with Silane A used in Example 1 was used.

The results are summarized in Tables 1 and 2.

Example 16 The same procedure as in Example 1 was carried out except that 71.4 parts of nylon mixed with Silane A used in Example 1 was used.

The results are summarized in Tables 1 and 2.

Example 17 The same procedure as in Example 1 was carried out except that 1102 parts of nylon into which Silane A had been kneaded was used.

The results are summarized in Tables 1 and 2.

Comparative Example 2 The same procedure as in Example 1 was carried out except that 122.4 parts of nylon into which Silane A used in Example 1 had been kneaded was used.

The results are summarized in Tables 1 and 2.

Example 18 Per 100 parts by weight of nylon 6 (1030B).

Example 1 was carried out in the same manner as in Example 1, except that 50.25 parts of pellets into which 0.5 parts by weight of Silane A had been kneaded in advance were used.

The results are summarized in Tables 1 and 2.

Example 19 Nylon 6 (1030B) 1.0 per 100 parts by weight
Pellets with silane A mixed in in advance) 50 parts by weight
．． The same procedure as in Example 1 was carried out except that 5 parts were used.

The results are summarized in Tables 1 and 2.

Comparative Example 3 Nylon 6 (1030B) 6.0 per 100 parts by weight
Pellets 53 in which parts by weight of Silane A are mixed in advance
Example 1 was carried out in the same manner as in Example 1, except that part was used.

The results are summarized in Tables 1 and 2.

Comparative Example 4 The same procedure as Example 1 was carried out except that Silane A was not used.

The results are summarized in Tables 1 and 2.

Comparative Example 5 The same procedure as Example 11 was carried out except that Silane A was not used.

The results are summarized in Tables 1 and 2.

Comparative Example 6 The same procedure as Example 12 was carried out except that Silane A was not used.

The results are summarized in Tables 1 and 2.

Comparative Example 7 The same procedure as Example 13 was carried out except that Silane A was not used.

The results are summarized in Tables 1 and 2.

Table 2-1 Table 2-2 Table 2-3 Table 2-4 Note 1) Carbon black (product name Diablack 1, manufactured by Mitsubishi Chemical Industries, Ltd.) Note 2) N-phenyl-N-isopropyl-p-phenylenediamine Note 3) N-oxydiethylene-2-benzothiazyl-sulfenamide (70%) Dibensothiazyl disulfide (10%) Mixture of the above two compounds Patent applicant Ube Industries, Ltd. Procedural amendment June 5, 1988

Claims (2)

[Claims] (1) 1 to 100 parts by weight of fine short fibers of polyamide capable of forming fibers are embedded in 100 parts by weight of vulcanizable rubber, and the polyamide and the rubber are bonded together via a silane coupling agent. A reinforced rubber composition characterized in that it is bonded. (2) A vulcanizable rubber, a fiber-formable polyamide, and 0.1 to 5.5 parts by weight of a silane coupling agent per 100 parts by weight of the polyamide are kneaded at a temperature equal to or higher than the melting point of the polyamide. A method for producing a reinforced rubber composition, which comprises extruding a kneaded product at a temperature higher than the melting point of the polyamide.