JPH0117494B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel reinforced rubber composition with excellent vulcanizate strength and modulus, and a method for producing the same. In the description of this specification, graft bonding refers to
Although the bonding method is unknown, it refers to some type of bond between nylon and vulcanizable rubber. Conventionally, reinforced rubber compositions have been produced by blending short fibers such as nylon, polyester, vinylon, etc. with vulcanizable rubber. but,
The strength and modulus of the vulcanizate of the thus obtained reinforced rubber composition is not sufficiently high, and it is desired to develop a reinforced rubber composition that provides a vulcanizate with even better strength and modulus. Therefore, as a method for manufacturing a reinforced rubber composition that improves the drawbacks of conventionally known reinforced rubber compositions, a method has been proposed in which vulcanizable rubber and powdered 1,2-polybutadiene are kneaded, extruded, and rolled with rolls. (Special Publication No. 55-41652). The above publication describes an experimental example of manufacturing a reinforced rubber composition that provides a reinforced elastic body with excellent strength and modulus. However, in the method for producing a reinforced rubber composition described in the above publication, the fiber-forming polymer is
1,2- with a structural content of 80% or more and a melting point of 130℃ or more
This method uses polybutadiene, and the resulting reinforced rubber composition has low strength fibers formed from the 1,2-polybutadiene, so the fibers are cut during rubber processing, especially during carbon black kneading, and the fiber length is shortened. This has the disadvantage that the modulus of the vulcanizate at low elongation becomes small. As a result of intensive research aimed at providing a reinforced rubber composition that does not have the above-mentioned drawbacks and a method for producing the same, the inventors discovered that they used nylon as the fiber polymer, and that vulcanizable rubber and nylon fibers were used. It has been discovered that a reinforced rubber composition that provides a vulcanizate with excellent strength and modulus can be obtained by using an initial condensate of an alkylphenol formaldehyde resin as a crosslinking agent,
completed this invention. That is, in this invention, 1 to 70 parts by weight of fine nylon fibers are embedded in 100 parts by weight of vulcanizable rubber, and at the interface of the fibers, the nylon and vulcanizable rubber are bonded to resol type alkyl. Reinforced rubber composition graft-bonded via an initial condensate of phenol formaldehyde resin, vulcanizable rubber and nylon with a molecular weight of less than 200,000, and the total amount of rubber and nylon per 100 parts by weight
0.2 to 2.5 parts by weight of an initial condensate of resol-type alkylphenol formaldehyde resin (hereinafter also simply referred to as alkylphenol formaldehyde resin) are kneaded at a temperature above the melting point of nylon and below 270°C. The kneaded material
If the ratio of rubber and nylon in the kneaded product is 1 to 70 parts by weight of nylon per 100 parts by weight of rubber, the ratio of rubber and nylon in the kneaded product is 1 part by weight of nylon per 100 parts by weight of rubber. Add more vulcanizable rubber to the entire rubber
After adding 1 to 70 parts by weight of nylon per 100 parts by weight to the kneaded product and kneading at a temperature above the melting point of nylon and below 270°C, Extrude with
The present invention relates to a method for producing a reinforced rubber composition, which comprises stretching an extrudate at a temperature lower than the melting point of nylon. The reinforced rubber composition of the present invention can provide a vulcanizate with excellent modulus and tensile strength at low and high elongations. Further, according to the method of the present invention, a reinforced rubber composition that provides a vulcanizate with excellent physical properties can be produced with good reproducibility from vulcanizable rubber, nylon, and alkylphenol formaldehyde resin by simple operations. Can be done. As the vulcanizable rubber in this invention, all rubbers that give a rubber elastic body by vulcanization can be used, such as natural rubber,
Examples include cis-1,4-polybutadiene, polyisoprene, polychloroprene, styrene-butadiene copolymer rubber, isoprene-isobutylene copolymer, ethylene-propylene-nonconjugated diene terpolymer, and mixtures thereof. .
Among these rubbers, natural rubber is preferred because it hardly gels when a mixture of vulcanizable rubber, nylon, and alkylphenol formaldehyde resin is kneaded, and then the kneaded product is extruded. The composition of the present invention comprises the above-mentioned vulcanizable rubber.
1-70 parts by weight of fine nylon fibers per 100 parts by weight,
Preferably, 10 to 60 parts by weight are embedded, and nylon and vulcanizable rubber are graft-bonded at the interface of the fibers via an alkylphenol formaldehyde resin as a crosslinking agent. The above-mentioned nylon fiber is nylon having a melting point of 190 to 225°C, preferably 200 to 220°C, such as nylon 6, nylon 610, nylon 12, nylon 611,
It is made of nylon 612, etc., and has an average diameter of
0.05~0.8μ, circular cross section, shortest fiber length is 1μ
As mentioned above, the fibers are embedded in the vulcanizable rubber in the form of fine fibers with molecules arranged in the direction of the fiber axis, preferably having a diameter of 8μ or more. Furthermore, at the interface of the nylon fibers, the nylon and the vulcanizable rubber are graft-bonded via an alkylphenol formaldehyde resin that is a crosslinking agent. The above-mentioned alkylphenol formaldehyde resin has the general formula (However, R is an alkyl group or a combination of a hydrogen atom and an alkyl group, X is a hydroxyl group or a halogen atom such as chlorine or bromine, m is 1 or 2, and n is a number from 2 to 15. Examples include resol-type precondensates obtained by reacting an alkylphenol such as cresol with formaldehyde or acetaldehyde in the presence of an alkali catalyst, and modified products thereof. In particular, as the alkylphenol formaldehyde resin, those having two or more methylol groups in the molecule can be suitably used. Examples of alkylphenol formaldehyde resins include Sumilight Resin PR-
22193, Sumilight Resin PR-50994, Sumilight Resin PR-175, Sumilight Resin PR-
50530, Sumilight Resin PR-51466, Sumilight Resin PR-22193, Sumilight Resin PR-
28633 (manufactured by Sumitomo Durez Co., Ltd.), Tatsuki Roll 201, Tatsuki Roll 250-, Tatsuki Roll 250-, Tatsuki Roll 250- (manufactured by Sumitomo Chemical Co., Ltd.), PP-
4507 (manufactured by Gunei Chemical Industry Co., Ltd.), Tamanol 521 (manufactured by Arakawa Chemical Industry Co., Ltd.), Schenectady
SP1059, Schenectady
SP1055 (manufactured by Schenectady Chemicals), CRR−
0803 (manufactured by Union Carbide (USA)), Synphorm C1000, -C1001 (Anchor Chem)
(manufactured by British company), Vulkaresat
510E, −532E, Vulkaresen
105E, −130E, Vulkaresol
Commercially available resin crosslinking agents such as 315E (manufactured by Hoechst (West Germany)) can be mentioned. Incidentally, the alkylphenol formaldehyde resin to which various auxiliary agents such as thickeners, solvents, and plasticizers are added and blended in the production of the alkylphenol formaldehyde resin naturally also falls under the alkylphenol formaldehyde resin referred to herein. In the reinforced rubber composition of the present invention, the strength of the fine nylon fibers embedded in the vulcanizable rubber is high, and the nylon and vulcanizable rubber on the surface of the nylon fibers are alkylphenol formaldehyde-based. Reinforced rubber that provides a vulcanizate that has excellent modulus and tensile strength at low and high elongations, and has excellent adhesion to materials such as natural rubber vulcanizates and steel because it is graft-bonded via a resin. A composition can be obtained. In addition, for example, in the case of an alkylphenol formaldehyde resin having a methylol (-CH ₂ OH) group, the graft bond is formed between a hydrogen atom of a methylene group in a vulcanizable rubber polymer molecule and an alkylphenol formaldehyde resin having a methylol (-CH 2 OH) group. Dehydration reaction of methylol with hydroxyl groups in resin molecules and amide groups in nylon polymer molecules

It is thought to be produced by a dehydration reaction between the hydrogen atom of the formula and the remaining methylol hydroxyl group in the alkylphenol formaldehyde resin molecule bonded to the vulcanizable rubber polymer molecule. In the reinforced rubber composition of the present invention, the vulcanizable rubber is graft-bonded to the nylon via the alkylphenol formaldehyde resin at the interface of the nylon fibers relative to the weight of the nylon fibers embedded in the vulcanizable rubber. The nylon and the vulcanizable rubber are mixed with the alkylphenol formaldehyde resin so that the graft ratio expressed by the weight ratio (vulcanizable rubber/nylon fiber) is 3 to 25% by weight, especially 5 to 20% by weight. Preferably, they are graft-bonded via. Furthermore, if the proportion of nylon fibers embedded in the reinforced rubber composition is outside the above range, the strength and modulus of the vulcanized product obtained by vulcanizing the composition will decrease, which is not preferable. The reinforced rubber composition of the present invention having the above-mentioned characteristics includes, for example, vulcanizable rubber and molecular weight
A kneaded product obtained by kneading nylon with a molecular weight of less than 200,000 and an alkylphenol formaldehyde resin in an amount of 0.2 to 2.5 parts by weight per 100 parts by weight of the total amount of rubber and nylon at a temperature above the melting point of nylon and below 270°C. If the ratio of rubber and nylon in the kneaded product is 1 to 70 parts by weight of nylon per 100 parts of rubber, the ratio of rubber and nylon in the kneaded product is 1 to 70 parts by weight of nylon per 100 parts of rubber. 1
If the amount exceeds parts by weight, add additional vulcanizable rubber, with 1 to 70 parts of nylon per 100 parts by weight of total rubber.
parts by weight, and then kneaded at a temperature above the melting point of nylon and below 270°C, extruded at a temperature above the melting point of nylon and below 270°C, and the extrudate is heated to a temperature above the melting point of nylon and below 270°C. It can be produced by stretching at a lower temperature. In the method of the present invention, the above-mentioned vulcanizable rubber and the above-mentioned nylon having a molecular weight (number average molecular weight) of less than 200,000, preferably from 10,000 to 100,000, and the total amount of the above-mentioned vulcanizable rubber and nylon of 100% by weight 0.2 to 2.5 parts by weight, preferably 0.7 to 2.0 parts by weight of the aforementioned alkylphenol formaldehyde resin are kneaded at a temperature above the melting point of nylon and below 270°C. The ratio of the vulcanizable rubber to nylon is
1 to 100 parts of nylon per 100 parts by weight of vulcanizable rubber
2000 parts by weight are preferred, especially 10 to 500 parts by weight. Vulcanizable rubber, nylon, and alkylphenol formaldehyde resin are kneaded at a temperature above the melting point of nylon and below 270°C, preferably at a temperature 5°C or more higher than the melting point of nylon and below 260°C. The process is carried out using a mixture of rubber, nylon, and alkylphenol formaldehyde resin in a molten state. The vulcanizable rubber, nylon, and alkylphenol formaldehyde resin are kneaded for preferably 1 to 15 minutes using a Brabender plastograph, Banbury mixer, roll, extruder, or the like. In the method of this invention, the above alkylphenol formaldehyde resin is used, and the vulcanizable rubber, nylon, and alkyl phenol formaldehyde resin are kneaded as described above to crosslink the vulcanizable rubber and nylon. This makes it possible to perform graft bonding via the alkylphenol formaldehyde resin, which is an agent, and to finely and uniformly disperse nylon in the vulcanizable rubber. If the amount of the alkyl phenol formaldehyde resin is less than the lower limit, it will be difficult to obtain a reinforced rubber composition that provides a vulcanizate with excellent adhesion to other members, and the amount of the alkyl phenol formaldehyde resin will be lower than the lower limit. is greater than the upper limit,
Gelation occurs due to reactions between vulcanizable rubbers or nylons, making it difficult to obtain a reinforced rubber composition that provides a vulcanizate with excellent modulus and strength. In the method of the present invention, there is no particular restriction on the order of addition of each component when kneading the vulcanizable rubber, nylon, and alkylphenol formaldehyde resin. In addition, for the purpose of preventing gelation of vulcanizable rubber during kneading and extrusion, N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylene is added to vulcanizable rubber. diamine, phenyl-α-naphthylamine,
Phenyl-β-naphthylamine, aldol-α
-Naphthylamine, reaction product of phenyl-β-naphthylamine and acetone, p-isopropoxy.
Diphenylamine, p-(p-toluene sulfonylamide)-diphenylamine, reaction product of diphenylamine and acetone, reaction product of diphenylamine and diisobutylene, N,N'-
Diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p
-phenylenediamine, N,N'-bis(1,4
-dimethylpentyl)-p-phenylenediamine,
Polymer of 2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1 , 2-dihydroquinoline, 2,6-di-tert-butyl-4-methylphenol, derivatives of 6-tert-butyl-3-methylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 4- hydroxy methyl-2,6
-di-tert-butylphenol, 2-methyl-4,6
-Dinonylphenol, 2,6-di-tert-butyl-
α-dimethylamino-p-cresol, 2,2-
Methylene-bis(4-methyl-6-cyclohexyl phenol), 4,4'-methylene-bis(2,
6-di-tert-butylphenol), 2,2'-methylene-bis(6-alphamethyl-benzyl-p-
cresol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 2,2'-dihydroxy-3,3'-di(α-methylcyclohexyl)-5,5'-dimethyl diphenylmethane Low-volatility anti-aging agents such as these can be blended. In the method of the present invention, a kneaded product obtained by kneading vulcanizable rubber, nylon, and an alkylphenol formaldehyde resin is prepared such that the ratio of rubber to nylon in the kneaded product is nylon per 100 parts by weight of rubber. When the amount is 1 to 70 parts by weight, preferably 10 to 60 parts by weight, it is extruded as is, and when the ratio of rubber and nylon in the kneaded product is more than 1 part by weight of nylon per 100 parts by weight of rubber, the above-mentioned vulcanization is performed. Additional vulcanizable rubber selected from available rubbers, with 1 to 70 parts of nylon per 100 parts by weight of total rubber.
Parts by weight, preferably 10 to 60 parts by weight, are added to the kneaded material, and further the melting point of nylon is
The mixture is kneaded at a temperature of 270°C or lower, preferably at least 5°C higher than the melting point of nylon and 260°C or lower, and then extruded. If the proportion of nylon in the kneaded product when extruding the kneaded product is less than the above-mentioned lower limit, it will not be possible to obtain a reinforced rubber composition that provides a vulcanizate with excellent strength and modulus; If the proportion of nylon in the kneaded material is greater than the above upper limit, it will be difficult to obtain a reinforced rubber composition that provides a vulcanizate with excellent adhesiveness. The kneaded material can be extruded into a string (or sheet) through a die having a circular or rectangular discharge opening, such as a circular die or a rectangular die, by an extrusion method known per se. When using a circular die, the inner diameter of the outlet should be 0.1 to 5 mm, and the ratio of the length of the outlet to the inner diameter of the outlet (L/D) should be 1 to 5 mm.
20 is preferable, and if a rectangular die is used, the slit gap should be 0.1 to 5 mm, and the width should be 0.2 to 5 mm.
It is preferable that the length of the die land is 200 mm and the length of the die land is 10 to 20 mm. Among the various dies described above, it is preferable to use circular dies. As the circular die, one having one discharge port or one having multiple discharge ports (multi-hold type) can be used. To extrude the kneaded product, use a known extruder, such as a screw type extruder, and keep the temperature of the screw tip above the melting point of nylon and 270°C.
It is preferable to extrude the kneaded material by setting the temperature of the circular die at the following temperature, above the melting point of nylon and below 270°C, especially at least 5°C higher than the melting point of nylon and below 260°C. In the method of this invention, by extruding the kneaded material as described above, the nylon in the vulcanizable rubber of the obtained extrudate becomes fibrous, and moreover, at the interface of the fibrous nylon, nylon and The above-mentioned vulcanizable rubber is graft-bonded via an alkylphenol formaldehyde resin as a crosslinking agent. In the reinforced rubber composition of the present invention, the above extrudate is air-cooled, preferably under continuous tension.
The nylon itself is cooled to a temperature below the melting point of the nylon by water cooling, cooling with an inert organic solvent such as chilled methanol, or by increasing the distance from the die to the take-up machine (also called the winder). It can be obtained by taking it to a take-up machine such as a bobbin or take-up roll by a known method, and then rolling it using a pair of rolling rolls or uniaxially stretching it using a stretching roll. . The temperature of the take-off machine when taking off the extrudate is preferably 0 to 100°C, and the draft ratio is preferably 1.5 to 50, particularly preferably 3 to 20. If the extrudate is taken without cooling, some of the fibrous nylon will become flat (in extreme cases, film-like),
Good results may not be obtained. Rolling with the aforementioned rolling rolls allows the diameter or thickness of the rolled product to be reduced to 2/3 of that of the extrudate by taking up and rolling.
The temperature of the rolling roll is 0 to 100℃.
is preferred. Further, the stretching using the stretching rolls is preferably carried out at a stretching ratio of 1.1 to 10, and the temperature of the stretching rolls is preferably 0 to 100°C. In the method of this invention, by stretching the extrudate as described above, the nylon in the vulcanizable rubber of the resulting reinforced rubber composition undergoes molecular orientation and is converted into a fibrous structure, resulting in strength. It is made of large fine nylon fibers. The reinforced rubber composition obtained by the method of the present invention contains 1 to 70 parts by weight of nylon per 100 parts by weight of vulcanizable rubber, and the nylon is in the form of fine fibers, and at the interface of the fibers. Nylon and vulcanizable rubber are graft-bonded via an alkylphenol formaldehyde resin that is a crosslinking agent, and can be used alone or blended with other vulcanizable rubbers to achieve low elongation and high elongation. It is possible to provide a vulcanizate with excellent modulus and tensile strength as well as adhesion to various members. By utilizing its excellent properties, the reinforced rubber composition of the present invention can be applied to tire internal parts such as belts, carcass, and beads, tire external parts such as treads and sidewalls, industrial products such as belts and hoses, and footwear materials. It can be used for the following purposes. Next, Examples and Comparative Examples will be shown. Obtained in Examples and Comparative Examples (strengthening)
The physical properties of the vulcanizate obtained using the rubber composition were measured in accordance with JISK6301, except for fatigue tests and abrasion tests. In the following description, all parts indicate parts by weight. Example 1 Viscosity is 1× in Brabender plastograph
10 Add 35 parts of ⁶ poise natural rubber (NR) and make 245
After masticating for 30 seconds at ℃ and rotor rotation speed of 50 rpm, 0.126 parts of alkylphenol formaldehyde resin (Tamanol 521, manufactured by Arakawa Chemical Industry Co., Ltd.) was added, and after further kneading for 30 seconds, 6-nylon (product name:
1030B, Ube Industries, Ltd., melting point 221℃, molecular weight 30000)
7 parts were added, and the mixture was further kneaded at 245°C for 4 minutes.
The obtained kneaded material was extruded into a string (diameter 2 mm) at a die temperature of 245°C using an extruder (manufactured by Hoake) having a circular die with a nozzle inner diameter of 2 mm and a length to inner diameter ratio (L/D) of 2. The extrudate is extruded into a funnel installed vertically below the nozzle (cooling water at 0°C is supplied into the funnel by a pump and pipes, and the supplied cooling water flows through the funnel, The water flows down into a cooling water storage container located vertically below the
From there the cooling water is pumped back into the funnel by pumps and pipes. ), then through the guide roll,
I wound it onto the bobbin with a draft ratio of 7. This rolled material was vacuum-dried at room temperature for a day and night to remove adhering water, and then rolled with a pair of rolling rolls with a roll gap of 0.1 mm and a temperature of 60° C. to obtain a reinforced rubber composition (sample 1). Fractionation and graft ratio measurement 2 g of the reinforced rubber composition obtained in Example 1 was added to 200 ml of benzene at room temperature to dissolve the rubber content in the reinforced rubber composition, and the resulting slurry was centrifuged at room temperature to dissolve the divided into a precipitated portion and a precipitated portion. After repeating the above operation seven times for the precipitated portion, the precipitated portion was dried to obtain nylon fibers.
This nylon fiber was dissolved in a mixed solvent of phenol and orthodichlorobenzene at a ratio of 1:3 (weight ratio), and analyzed by ¹ H nuclear magnetic resonance spectroscopy (internal standard: tetramethylsilane).
From the chart, cut out the area for each peak of the methyl group and methylene group originating from natural rubber, the methylene group adjacent to the CO group originating from 6-nylon, the methylene group adjacent to the NH group, and the other three methylene groups. The graft ratio was calculated by determining the molar ratio of 6-nylon and natural rubber using the method. In addition, the shape of the nylon fiber described above can be changed to approximately
Scanning microscope (Co., Ltd.) at 10,000x magnification for 200
(manufactured by Hitachi, Ltd.). The fibers were extremely thin fibers with a circular cross section. The results are shown in Table 1. Evaluation Test The reinforced rubber composition obtained in Example 1 was vulcanized at 150° C. for 40 minutes according to the formulation shown in Table 2, and its physical properties were measured. The results are shown in Table 2. Example 2 35 parts of natural rubber (NR) of the same type as used in Example 1 was put into a Brabender plastograph, and after masticating at 245°C and 50 rpm for 20 seconds, N-(3-
methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylenediamine [Notsukura Tsuku G-1, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.]
After adding 0.35 parts and kneading for another 10 seconds, Example 1
17.5 parts of 6-nylon of the same type used in Example 1 was added, and after kneading for an additional 4.5 minutes, 0.788 parts of alkylphenol formaldehyde resin of the same type used in Example 1 was added, and the mixture was heated at 245°C and 100 rpm. The mixture was kneaded for an additional 2 minutes. A reinforced rubber composition (sample 2) was obtained in the same manner as in Example 1 using the obtained kneaded product. The results are summarized in Tables 1 and 2. Comparative Example 1 35 parts of the same type of natural rubber used in Example 1 was placed in a Brabender Plastograph, and 245 parts of natural rubber was added.
After kneading for 1 minute at 50 rpm, 10.5 parts of 6-nylon of the same type as used in Example 1 was added and kneaded for an additional 4 minutes. A reinforced rubber composition (sample 3) was prepared in the same manner as in Example 1 using the obtained kneaded product.
I got it. This reinforced rubber composition contained many nylon film-like materials. The results are summarized in Tables 1 and 2. Example 3 40 parts of 6-nylon of the same type as used in Example 1 was placed in a Brabender plastograph, and
After kneading for 9 minutes at 245°C and 50 rpm to completely melt the 6-nylon, 15 parts of the same type of natural rubber as used in Example 1 was added, and after kneading for an additional 1.5 minutes, Example 0.275 parts of alkylphenol formaldehyde resin of the same type as used in 1 was added and kneaded for an additional 3.5 minutes. The obtained kneaded product (first-stage kneaded product) was taken out from the Brabender Plastograph and granulated. Next, 30.7 parts of the natural rubber was put into a Brabender Plastograph and masticated at 245° C. and 50 rpm for 30 seconds, and then 14.4 parts of the granulated kneaded material was added and kneaded for an additional 4.5 minutes. This kneaded material (second stage kneaded material) was extruded into a string shape in the same manner as in Example 1, and the extruded material was passed through the same funnel as used in Example 1, and was only tensioned under water flow without being wound up on a bobbin. It was stirred and cooled. The obtained string-like extrudate was rolled in the same manner as in Example 1 to obtain a reinforced rubber composition (Sample 4). The results are summarized in Tables 1 and 2. Example 4 The amount of alkylphenol formaldehyde resin
A reinforced rubber composition (sample 5) was obtained in the same manner as in Example 3, except that the amount was changed from 0.275 part to 0.825 part, and the draft ratio when winding the extrudate onto a bobbin was changed from 7 to 7.7. The results are summarized in Tables 1 and 2.
Shown in the table. Example 5 A reinforced rubber composition (sample 6) was produced in the same manner as in Example 3, except that the amount of granulated kneaded material was changed from 14.4 parts to 20.7 parts, and the amount of natural rubber was changed from 30.7 parts to 24.4 parts. I got it. The results are summarized in Tables 1 and 2. Example 6 N- during first-stage kneading and second-stage kneading
A reinforced rubber composition (Sample 7) was prepared in the same manner as in Example 5, except that 1 PHR of (3-methacryloyloxy-2-hydroxylpropyl)-N'-phenyl-p-phenylenediamine was added to each natural rubber. I got it. The results are summarized in Tables 1 and 2.
Shown in the table. Example 7 40 parts of 6-nylon of the same type as used in Example 1 was charged into a Brabender plastograph, and
After kneading for 9 minutes at 245°C and 50 rpm to completely melt the 6-nylon, 100 parts of natural rubber of the same type used in Example 1, 5.5 parts of alkylphenol formaldehyde resin and N-(3 -methacryloyloxy-2-hydroxylpropyl)-
15.975 parts of a mixture obtained by mixing 1.0 part of N'-phenyl-p-phenylenediamine at 60° C. using a 3-inch roll were added and kneaded for an additional 3.5 minutes.
The obtained kneaded product (first-stage kneaded product) was taken out from the Brabender Plastograph and granulated. Next, 30.721 parts of the above natural rubber and 0.307 parts of N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylenediamine were charged into a Brabender plastograph.
After masticating at 245° C. and 50 rpm for 1 minute, 14.533 parts of the granulated kneaded material was added and kneaded for an additional 4.5 minutes. A reinforced rubber composition (Sample 8) was obtained in the same manner as in Example 1 using the obtained kneaded product (second stage kneaded product). The results are summarized in Tables 1 and 2.
Shown in the table. Example 8 The amount of granulated kneaded material was changed from 14.533 parts to 17.991 parts, the amount of natural rubber was changed from 30.721 parts to 27.322 parts, and N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl A reinforced rubber composition (Sample 9) was obtained in the same manner as in Example 7, except that the amount of -p-phenylenediamine was changed from 0.307 parts to 0.273 parts. The results are summarized in Tables 1 and 2. Example 9 The amount of the granulated kneaded material was changed from 14.533 parts to 20.991 parts, and N-(3-methacryloyloxy-2-
Reinforced rubber was prepared in the same manner as in Example 7, except that the amount of hydroxypropyl)-N′-phenyl-p-phenylenediamine was changed from 0.307 parts to 0.244 parts, and the amount of natural rubber was changed from 30.721 parts to 24.375 parts. A composition (sample 10) was obtained. The results are summarized in Tables 1 and 2. Example 10 The amount of granulated kneaded material was changed from 14.533 parts to 23.614 parts, the amount of natural rubber was changed from 30.721 parts to 21.797 parts, and N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl A reinforced rubber composition (Sample 11) was obtained in the same manner as in Example 7, except that the amount of -p-phenylenediamine was changed from 0.307 parts to 0.218 parts. The results are summarized in Tables 1 and 2. Comparative Example 2 The amount of granulated kneaded material was changed from 14.533 parts to 27.988 parts, the amount of natural rubber was changed from 30.721 parts to 17.500 parts, and N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl A reinforced rubber composition (Sample 12) was obtained in the same manner as in Example 7, except that the amount of -p-phenylenediamine was changed from 0.307 parts to 0.218 parts. This reinforced rubber composition contained a large number of nylon film materials as well as nylon fibers. The results are summarized in Tables 1 and 2. Example 11 40 parts of 6-nylon of the same type used in Example 1 was placed in a Brabender plastograph, and
After kneading for 9 minutes at 245°C and 50 rpm to completely melt the 6-nylon, 100 parts of the same type of natural rubber as used in Example 1, N-(3-methacryloyloxy-2-hydroxy 15.425 parts of a mixture obtained by mixing 1.0 part of (propyl)-N'-phenyl-p-phenylenediamine and 1.833 parts of alkylphenol formaldehyde resin at 60°C using a 3-inch roll were added and kneaded for an additional 3.5 minutes. The obtained kneaded material was taken out from the Brabender Plastograph and granulated. Next, 24.375 parts of the above natural rubber and 0.244 parts of N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylenediamine were placed in a Brabender plastograph, and heated at 245°C for 50 r. pm
After masticating for 30 seconds with
and kneaded for 4.5 minutes. A reinforced rubber composition (Sample 13) was obtained in the same manner as in Example 1 using the obtained kneaded product. The results are summarized in Tables 1 and 2. Examples 12, 13 The amount of alkyl phenol formaldehyde resin (Tamanol 521) was changed from 1.833 parts to 3.667 parts, and the amount of the granulated kneaded product was changed from 20.784 parts to 20.888 parts (Example 12), or the amount of alkyl phenol formaldehyde resin (Tamanol 521) was changed from 20.784 parts to 20.888 parts. The amount was changed from 1.833 parts to 7.333 parts, and the amount of granulated kneaded material was changed from 20.784 parts to 21.094 parts.
part, and the kneading temperature and extrusion temperature were changed from 245℃.
A reinforced rubber composition (sample 14, sample
15). The results are summarized in Tables 1 and 2. Comparative Example 13 Table 2 shows the results of the evaluation test for the same type of natural rubber used in Example 1 (Sample 16).

【table】

【table】

【table】

【table】

[Table] Comparative Example 4 100 parts of natural rubber (NR) of the same type as used in Example 1 was put into a Brabender Plastograph, and after masticating at 80°C and 50 rpm for 30 seconds, 6-nylon Add 5 parts of thread (length 2 mm) and masticate for 30 seconds, then add 15 parts of silica, 3 parts of zinc white, 2.5 parts of resorcinol, and 2 parts of stearic acid according to the formulation of the HRH system, and masticate for 4 minutes. Kneaded. The obtained kneaded product was put into a 3-inch roll, and then 2 parts of sulfur, 1.6 parts of hexamethylenetetramine, and 1 part of dibenzothiazyl disulfide were added,
The mixture was kneaded at 80°C, and the kneaded product (sample 17) was sheeted out, fed into a mold, and vulcanized at 150°C for 40 minutes, and its physical properties were measured. The results are shown in Table 3. Comparative Example 5 Comparative Example 4 except that 6-nylon thread was not blended
A kneaded product (sample 18) was obtained in the same manner as above, and its physical properties were measured. The results are shown in Table 3.

【table】

[Table] Samples 1-2, Samples 4-11, Sample 13
The stress-strain curve of the vulcanizate obtained from Samples No. 15 to 15 had a smooth "inverted S-shape" shape. On the other hand, in the stress-strain curves of the vulcanizates obtained from Sample 3 and Sample 17, wave-like disturbances occurred from around 50% strain. The reinforced rubber composition of Example 9 and the natural rubber (NR) of Comparative Example 3 were vulcanized at 150° C. for the vulcanization time shown in Table 4, and their physical properties were measured. The pico wear test of the vulcanizate was performed according to ASTM D2228, and the fatigue test was performed using a constant load tensile fatigue tester (Toyo Seiki) in air at 100°C.
Co., Ltd., S6T type) with a constant load of 30Kg/cm ²
50% modulus retention rate and tensile breaking strength retention rate after tensile ⁴ times at 1 × 10 [(value after fatigue test / value before fatigue test) × 100, %], constant load 50 kg /
The number of times of tension (fatigue life) until tensile breakage occurred at cm ² was determined. The results are shown in Table 4.

[Table] The results shown in Table 4 show that the reinforced rubber composition of the present invention provides a vulcanizate with extremely excellent properties at high temperatures and under high stress.

Claims (1)

[Claims] 1. Average diameter of 0.05 to 100 parts by weight of vulcanizable rubber.
1 to 70 parts by weight of 0.8μ fine nylon fibers are embedded, and at the interface of the fibers, nylon and vulcanizable rubber are grafted via an initial condensate of a resol type alkylphenol formaldehyde resin. bonded reinforced rubber composition. 2 Vulcanizable rubber, nylon with a molecular weight of less than 200,000, and per 100 parts by weight of the total amount of rubber and nylon
0.2 to 2.5 parts by weight of an initial condensate of a resol type alkylphenol formaldehyde resin are kneaded at a temperature above the melting point of nylon and below 270°C,
If the ratio of rubber and nylon in the kneaded product is 1 to 70 parts by weight of nylon per 100 parts by weight of rubber, use the kneaded product as is; If the amount of nylon per part is more than 1 part by weight, add additional vulcanizable rubber, with 1 to 1 part of nylon per 100 parts by weight of total rubber.
70 parts by weight is added to the kneaded product, which is further kneaded at a temperature above the melting point of nylon and below 270°C, and then extruded at a temperature above the melting point of nylon and below 270°C, and the extrudate is made into nylon. A method for producing a reinforced rubber composition, characterized by stretching at a temperature lower than its melting point.