JPS62256850A - Rubber composition for hose - Google Patents

Abstract

PURPOSE:To obtain a rubber compsn. which gives a rubber hose having high elasticity and excellent resistance to oil and thermal aging, by blending EPDM with a specified rubber compsn. contg. short fibers of a thermoplastic polymer and an antioxidant. CONSTITUTION:A rubber compsn. which satisfies the following conditions (a)-(c). (a): it contains a reinforced rubber compsn. A contg. 2-70pts.wt. thermoplastic polymer per 100pts.wt. ethylene/propylene/polyene copolymer rubber (EPDM), wherein fine short fibers of the thermoplastic polymer having a polyamide group in its polymer molecule are dispersed in a continuous phase composed of EPDM and the thermoplastic polymer is grafted onto EPDM through a novolak type phenolic resin at the interfaces of the short fibers, (b): it contains 0-80pts.wt. EPR (B) composed of ethylene/propylene of 50/50-90/10 per 100pts. wt. rubber component in the compsn. A, and (c): it contains not less than 0.5pts. wt. antioxidant per 100pts.wt. in total of the rubber components in the compsn. A and the rubber B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rubber composition for a hose whose vulcanizate provides a rubber hose with high elasticity, excellent oil resistance and heat aging resistance.

[Conventional technology]

Rubber hoses are generally divided into a cover rubber and an inner tube with reinforcing (fiber) rCA in between. The physical properties required for the cover rubber include weather resistance, ozone resistance, cold resistance, heat aging resistance, etc., and the physical properties necessary for the inner tube include, of course, resistance to objects passing inside the hose (abrasion resistance, oil resistance, chemical resistance, etc.).

Ethylene-propylene-polyene copolymer rubber (r
Due to the structure of its rubber, the vulcanizate obtained from EPDM (sometimes abbreviated as EPDM J) has excellent heat resistance, ozone resistance, chemical resistance, electrical insulation, etc., and is also flexible. Therefore, it is suitable for use in radiator hoses, which are one of the hose parts around automobile engines that are exposed to intense mechanical vibrations and high temperature atmospheres.

Recently, with the improvement of engines due to the demand for improved fuel efficiency of automobiles, the temperature of the engine has increased, and the temperature around the engine, which used to be below 100 degrees Celsius, is now exposed to higher temperatures than before, to over 100 degrees Celsius. ing. Therefore, hoses used around the engine are required to have even higher resistance to heat aging. In addition, during maintenance inspections around the engine, lubricating oil or gasoline may adhere to rubber hoses, etc., or lubricating oil vapor may fill the engine compartment due to aging gaskets around the engine, causing the above hoses to become damaged. It is desired to develop a rubber material that satisfies both heat aging resistance and oil resistance.

JP-A-56-98249 discloses that ethylene/propylene/polyene copolymer rubber, ethylene/propylene copolymer rubber, organic peroxide, vulcanization aid, antioxidant, processing aid, and other specific compounds are used. A method for producing a vulcanizate with excellent heat aging resistance by peroxide vulcanization of a composition is disclosed, but the vulcanizate has poor oil resistance;
It is only comparable to conventional EPDE vulcanizates.

In order to improve the oil resistance of EPDH, it may be blended with a rubber having excellent oil resistance, such as acrylonitrile-butadiene copolymer rubber, or it may be mixed with the above blend as shown in JP-A-56-109230. Thiazolylsulfenamide or N-oxydiethylene-2-benzothiazolylsulfenamide is used as a vulcanization accelerator, or EPD is used as in JP-A-53-67754.
Attempts have been made to blend a graft copolymer of M and vinyl chloride with RPDH, but it is difficult to apply this to rubber hoses that require oil resistance. Moreover, in the above-mentioned EPDM compositions with improved oil resistance, the excellent physical properties originally possessed by EPDM vulcanizates are often impaired; for example, I! At present, it is inferior in terms of heat aging properties.

As mentioned above, rubber hoses have a reinforcing layer between the inner tube and cover rubber, increasing the strength of the rubber hose, and cotton cloth or chemical fiber cloth is used as the reinforcing material. However, the affinity and adhesion between the reinforcing material and EPDM are poor, and as a result, if the rubber hose is exposed to a high temperature atmosphere with severe mechanical vibration for a long time, the interface between the reinforcing material and EPDM will deteriorate. Cracks occur and grow, eventually leading to damage to the rubber hose, resulting in fluid leaks, etc. Therefore, in order to increase the affinity and adhesion between the reinforcing material and EPDM,
Although surface treatment methods for reinforcing materials have been studied, no effective treatment method has yet been found.

[Problem that the invention seeks to solve]

As mentioned above, there are rubber compositions for hoses with excellent heat aging resistance, but they are inferior in oil resistance, and EPOM compositions with slightly improved oil resistance lose the other excellent physical properties of EPDM. Furthermore, with regard to reinforcing materials, no effective surface treatment method has yet been found to improve their affinity and adhesion with rubber compositions.

An object of the present invention is to provide a rubber composition for a hose that provides an inner pipe or cover rubber material with excellent heat aging resistance and oil resistance, and a high elastic reinforcing material with excellent adhesion to the inner pipe or cover rubber. .

[Means to solve problems]

The above object is achieved by a rubber composition for a hose that satisfies the following conditions (a) to (c) and is excellent in high elasticity, oil resistance, and heat aging resistance.

(a) In the continuous phase consisting of ethylene-propylene-polyene copolymer rubber, an amide group (-C-
Fine short fibers of a thermoplastic polymer having (NH- group) are dispersed, and at the interface of the short fibers, the thermoplastic polymer and the ethylene-propylene-polyene copolymer rubber are mixed with novolac type phenol. (b) a polyene component, in which the thermoplastic polymer is grafted via a commercially available oil, and the amount of the thermoplastic polymer is 2 to 70 parts by weight per 100 parts by weight of the copolymer rubber component; Does not contain ethylene/propylene copolymer rubber, or has a molar ratio of ethylene and propylene (
ethylene/propylene) from about 50,150 to about 90/
10 and contains 80 parts by weight or less of ethylene-propylene copolymer rubber B that does not contain a polyene component per 100 parts by weight of the rubber component in the reinforced rubber composition A, and (c) together with the reinforced rubber composition A. Contain 0.5 parts by weight or more of an antioxidant per 100 parts by weight of the rubber components in the total amount of polymerized rubber B.

In terms of heat aging resistance, the ethylene/propylene copolymer rubber composition obtained in the present invention shows that even if it is exposed to an air atmosphere at 160°C for one week, the product of the breaking strength and the breaking elongation, that is, the energy required for breaking. The standard value is to maintain an initial value of 172 or higher, and exhibit extremely excellent heat aging resistance, which may even be higher than the initial value. In terms of oil resistance, the oil absorption of conventional EPDM vulcanizates is about 374 or less, and in some cases it is 175 or less.It is a copolymer rubber composition with a good balance of heat aging resistance and oil resistance. be.

Further, the copolymer rubber composition obtained in the present invention contains a large amount of thermoplastic polymer short fibers (10 parts by weight or more of short fibers per 100 parts by weight of the rubber component).
In this case, the tensile strength at 100% elongation of the vulcanizate shows high elasticity about 3 to 4 times that of a normal EPD-vulcanizate, and 50%
Since it exhibits the above-mentioned high elasticity even at the following low elongation, it can also be used as a reinforcing layer for rubber hoses.

Such effects of the invention are achieved as a combined effect because the rubber composition for hoses of the invention satisfies all of the requirements (a) to (c) above. Among the requirements (a) to (c), some individual requirements or a combination of these two requirements are already known, but a composition that satisfies all the requirements is not known, and of course, The use of compositions such as the present invention for the manufacture of hoses is completely unknown.

For example, as mentioned above, according to JP-A-56-98249, it is possible to provide a composition with excellent heat aging resistance, but only a limited vulcanization method called peroxide vulcanization can be applied. However, since the oil resistance does not go beyond that of ordinary EPDH, the uses of the composition are naturally limited.

Further, according to the invention of a rubber hose disclosed in JP-A-60-171134, vulcanizable rubber is a continuous phase, and fine short fibers of a thermoplastic polymer having an amide group in the polymer molecule are added to the continuous phase. A reinforced rubber composition (A) in which the polymer and vulcanizable rubber are dispersed and grafted via a novolac type phenolic resin at the interface of the short fibers, natural rubber, polyisoprene, or both. mixture (B), diene rubber (C) excluding natural rubber and polyisoprene, and carbon black (D)
This invention relates to a rubber hose characterized by using a rubber composition in the inner pipe portion which is a mixture of the following and satisfies the following conditions (i) to (iv), and these conditions are (i) the above-mentioned conditions. The amount of thermoplastic polymer is 1 to 20 parts by weight based on 100 parts by weight of the total rubber component, and (ii) (A
) The total proportion of natural rubber and/or polyisoprene in component (B) is 30 to 100% by weight based on the total rubber component, and (iii) the amount of carbon black is based on 100 parts by weight of the total rubber component. is 30 to 70 parts by weight,
(iv) The hardness of the vulcanized product of the rubber composition is 55 to 80 according to JIS K6301 A type spring type hardness test.
'is.

The rubber hose disclosed in the above publication has a high green modulus, a small swell ratio, and excellent workability and fluidity, even though the inner tube rubber composition used has a low Mooney viscosity, so it can be extruded uniformly in a short time. It is said that it has good hardness and wear resistance. However, the above invention requires the inclusion of natural rubber and/or polyisoprene, and because of this condition, oil resistance and heat aging resistance are poor, making it unsuitable for applications that require these physical properties.

Therefore, from these known examples, it is impossible to predict the remarkable effects of a rubber composition for a hose that satisfies all of the requirements (a) to (c) of the present invention.

The reinforced rubber composition A used in the present invention is JP-A-60-1
It can be prepared in a manner similar to that disclosed in Example 13 of Publication No. 39129.

That is, fine fibrous materials of thermoplastic polymer having amide groups in the polymer molecules are dispersed in a continuous phase consisting of ethylene-propylene-polyene copolymer rubber, and at the interface of the fibrous materials, The polymer and EPD
This is a reinforced rubber composition in which M is grafted via a novolac type phenolic resin. The EPDM has a Mooney viscosity (MLl, , , 100°C) of 5 to 100°C.
80, EP with an iodine number of 4 to 30 and a molar ratio of ethylene units to propylene units of 55/45 to 85/15
DM is preferably used.

The fine fibrous material of the thermoplastic polymer has a melting point of 190
~260℃ nylon 6, nylon 66, nylon 61
It is made of nylon such as 2 and has an average diameter of 0.0.
5 to 0.8 microns, circular cross section, fiber length of 10 microns or more, and 90% by weight or more of the fibers are dispersed in the vulcanizable rubber in the form of fine short fibers of 1000 microns or less.

Moreover, at the interface of the short fibrous material, a thermoplastic polymer having an amide group in the polymer molecule and EPDM are grafted via a novolak-type phenolic resin (hereinafter sometimes simply abbreviated as "novolac"). ing.

The above-mentioned novolac is a condensation reaction of phenols such as phenol, bisphenols, and formaldehyde (paraformaldehyde may also be used) using a catalyst known per se, such as an acid such as sulfuric acid, hydrochloric acid, phosphoric acid, or oxalic acid. These are soluble and fusible resins obtained by this method, and modified products thereof. As the novolak, for example, a novolac type phenol formaldehyde initial condensation product, a novolak type lactam bisphenol F-formaldehyde initial condensation product, a novolak type styrenated phenol-phenol-formaldehyde initial condensation product, etc. can be suitably used.

Reinforced rubber composition A comprises 100 parts by weight of EPDM, 2 to 50 parts by weight of the thermoplastic polymer, 20 parts by weight or less of a processing aid such as a tackifier, and a total of 100 parts by weight of EPDM and thermoplastic polymer. 0.2 to 5 parts by weight of novolak and 1 to 50 parts by weight of formaldehyde donor per 100 parts by weight of novolak are heated at a temperature above the melting point of the thermoplastic polymer, particularly at least 5°C higher than the melting point of the thermoplastic polymer, at 280°C. Knead at the following temperature for 1 to 30 minutes using a Prahender Plastograph, Banbury mixer, roll, extruder, etc., extrude the kneaded product at a temperature above the melting point of the thermoplastic polymer and below 280°C, and then roll it. A method in which the thermoplastic polymer is dispersed in the EPDM as a fine fibrous material, and the thermoplastic polymer and EPDM are grafted via a novolak at the interface of the fibrous material. It can be manufactured by In the above method, the extruded strand may be wound up (take-up) and then the strand may be rolled (stretched) at a temperature below the melting point of the thermoplastic polymer.

In this reinforced rubber composition A, E grafted onto the thermoplastic polymer relative to the weight of the fine short fibers of the thermoplastic polymer dispersed in the EPDM continuous phase.
The thermoplastic polymer forming the fibrous material and the EPDM contain the novolak so that the grafting ratio expressed by the weight ratio of PDM (EPDM/fine short fibrous material of thermoplastic polymer) is 2 to 20% by weight. Preferably, they are graft-bonded via a bond.

As the formaldehyde donor, a compound that generates formaldehyde upon heating is used. For example, as a formaldehyde donor, hexamethylenetetramine, acetaldehyde ammonia: (CHt
-CI Nil□〕1. Rose formaldehyde, α-
polyoxymethylene, polyvalent methylolmelamine derivative,
Examples include oxazolidine derivatives and polyvalent methylolated acetylene urea.

In reinforced rubber composition A, the novolak and formaldehyde donor described above are used and HPD? By kneading '1, a thermoplastic polymer having an amide group in the polymer molecule, a novolak, and an aldehyde donor as described above, EPDM and the thermoplastic polymer are graft-bonded via the novolak, and
The thermoplastic polymer can be uniformly dispersed in fine particles (the particle size of the dispersed thermoplastic polymer is usually 1 to 2 μm), and by winding up the extrudate, the thermoplastic polymer can be dispersed into fine short fibers. It becomes a shape.

As is clear from the examples, a reinforced rubber composition in which EPDM is further mixed and dispersed in the reinforced rubber composition, that is, reinforced rubber composition A is diluted with ordinary EP leaves as a master bunch, can also be used as reinforcement of the present invention. It can be rubber composition A.

The reinforced rubber composition A in the present invention contains EPDM 100
2 to 70 parts by weight of thermoplastic polymer short fibers are dispersed in each part by weight, but if the short fibers are less than 2 parts by weight, oil resistance and heat aging resistance will decrease; In this case, the operation at the time of compounding becomes a national problem.

In the present invention, ethylene-propylene copolymer rubber B containing no polyene component is not blended at all, or even if blended, the amount is limited to 80 parts by weight or less per 100 parts by weight of the rubber component in reinforced rubber composition A. If more than 80 parts by weight is added, the heat aging resistance of the vulcanizate will be significantly reduced, and the oil resistance will also be slightly reduced. The copolymer rubber B has a molar ratio of ethylene units to propylene units (ethylene/propylene) of about 50,150 to about 90/10, preferably about 55/45 to about 8.
It is 5/15. When the molar ratio is less than about 50,150, the heat aging resistance of the hose decreases, and when the molar ratio exceeds about 90/10, the rubber properties are poor.

Copolymer rubber B of the present invention does not contain a polyene component, but
Such rubber can be obtained, for example, by copolymerizing ethylene and propylene under a Ziegler catalyst. However, a small amount of double bonds may exist in the molecular chain due to a disproportionation reaction, etc., but such copolymer rubber usually has an iodine value of 2 or less, and is suitable as copolymer rubber B of the present invention. Can be used for

In the rubber composition for hoses of the present invention, the amount of the antioxidant is 0.5 parts by weight or more based on 100 parts by weight of the total rubber components, but is usually about 0.5 to about 4 parts by weight. If the content is less than 0.5 parts by weight, the heat aging resistance will be poor, and if the content exceeds about 4 parts by weight, the effect will not be particularly enhanced.

As the antioxidant used in the present invention, aldol-α ~
Naphthylamine, 2.2.4-1-rifthyl-1,2-
Dihydroquinoline polymer, 6-nitoxy 2.2.4-
tomethyl-1,2-dihydroquinoline, phenyl-β-
naphthylamine, N-phenyl-N'-isopropyl-
p-phenylenediamine, diphenylamine derivative, 2
-Amine/aldehydes, amine/ketones, amines, imidazoles, dithiocarbamates, etc. such as mercaptobenzimidazole, 2-mercaptobenzimidazole zinc salt, and nickel dibutyldithiocarbamate are preferably used, but 2° 6-di~L-butyl-
Phenolic antioxidants such as 4-methylphenol and styrenated phenol are also effective.

In the present invention, in addition to the requirements (a) to (c) described above, an inorganic filler may be added as an optional component. Usually, the amount of inorganic filler blended is reinforced rubber composition A and copolymer rubber B.
300 parts by weight or less, preferably about 20 to 250 parts by weight, per 100 parts by weight of the total rubber components. Incorporation of an inorganic filler increases the surface hardness and tensile strength of the vulcanizate, giving favorable results, but if it is used in an amount exceeding about 300 parts by weight, the hose loses its rubber properties, such as loss of flexibility.

Examples of inorganic fillers that can be used include carbon blank, silicic acid compounds such as anhydrous silicic acid, hydrated silicic acid, or synthetic silicates, calcium carbonate, and clay.

Further, in the present invention, a softener can be added as an optional component. Usually, the amount of the softener blended is 200 parts by weight or less, preferably 100 parts by weight or less, per 100 parts by weight of the total rubber components of the reinforced rubber composition A and the copolymer rubber B. The softeners mentioned here include paraffinic process oils, naphthenic process oils, aromatic process oils, petrolatum, petroleum resins, polymerized high-boiling point strong aromatic oils, paraffin, liquid paraffin, mineral oils such as white oil, etc. Vegetable oil softeners such as cottonseed oil, rapeseed oil, balm oil, rosin, pine tar, black subs, white subs, fatty acids such as ricinoleic acid, palmitic acid, stearic acid, lauric acid, barium stearate, Refers to fatty acid salts such as calcium stearate and zinc stearate.

Furthermore, in the present invention, a processing aid can be added as an optional ingredient. The amount of the processing aid J is 2 per 100 parts by weight of the total rubber components of reinforced rubber composition A and copolymer rubber B.
Keep it below 0 parts by weight. If more than 20 parts by weight is added, the heat aging resistance of the vulcanizate will be significantly lowered, and the 100% elongation strength will also be lowered. The processing aids mentioned here include coumaron/indene resin, phenolic resin, terpene resin, synthetic polyterpene resin, aromatic hydrocarbon resin, aliphatic cyclic hydrocarbon resin, polybutene, active polypropylene, and liquid polybutadiene. , tackifiers such as low molecular weight butyl rubber, phthalic acid derivatives, isophthalic acid derivatives, tetrahydrophthalic acid derivatives, adipic acid derivatives, azelaic acid9. maleic acid derivatives, fumaric acid derivatives, trimellitic acid derivatives, citric acid derivatives, itaconic acid derivatives, oleic acid derivatives, ricinoleic acid derivatives, stearic acid derivatives, fatty acid derivatives, sulfonic acid derivatives, phosphoric acid derivatives, glycol derivatives , refers to plasticizers such as glycerin derivatives, paraffin derivatives, and epoxy rust conductors.

The rubber composition for a hose of the present invention is used as a rubber hose after vulcanization, and as a vulcanization method, a sulfur vulcanization method or an organic peroxide vulcanization method is selectively used depending on the formulation of the composition. That is, rubber component 1 of reinforced rubber composition A
When the copolymer rubber B is about 20 parts by weight or less per 00 parts by weight, sulfur vulcanization is possible, and when the copolymer rubber B is 80 parts by weight or less, organic peroxide vulcanization is possible.

In the sulfur vulcanization method, sulfur such as powdered sulfur, precipitated sulfur, and highly dispersed sulfur is used. Low sulfur vulcanization, in which the amount of sulfur is 1 part by weight or less per 100 parts by weight of the rubber component of the Mi product, is recommended.

In the organic peroxide vulcanization method, dicumyl peroxide,
1.1'-di(t-butylperoxy)3.3.5-trimethylcyclohexane, di((-butylperoxy)
Diisopropylbenzene, 2,5-dimethyl-2,5-
Organic peroxides such as di(t-butylperoxy)hexane and 2,5-dimethyl-2,5-di(L-butylperoxy)hexane are used, but their drawback is that they leave behind an odor.

When using sulfur as a vulcanizing agent, thiurams such as tetramethylthiuram disphite, tetramethylthiuram disphite, tetramethylthiuram monosulfide,
Thiazoles such as 2-mercaptobenzothiazole, dihenzothiazyl disulfide, N-oxydiethylene-2-hendithiazole sulfenamide, zinc salt of 2-mercaptobenzothiazole, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, N-
Dithiocarbamates such as zinc ethylphenyldithiocarbamate, sodium s-n-butyldithiocarbamate, tellurium diethyldithiocarbamate, and mixtures thereof are used as vulcanization accelerators, and metal oxides such as zinc oxide, stearic acid, oleic acid, etc. Such fatty acids are used as vulcanization accelerating aids.

When using organic peroxides as a vulcanizing agent, sulfur, sulfur compounds such as dipentamethylenethiuram tetrasulfide, oxime compounds such as p-quinone dioxime, p,p'-dibenzoylquinone dioxime, triaryl Allyl compounds such as lucyanurate, diallyl cyanurate, diallyl phthalate, methacrylic compounds such as ethylene dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, maleimide compounds such as metaphenylene bismaleimide, toluylene bismaleimide, Mixtures thereof are used as vulcanization aids.

There are no particular restrictions on the method of blending the vulcanizing agent, vulcanization accelerator, and vulcanization aid into the rubber composition for hoses of the present invention.
A compounding method known per se can be employed.

It is recommended that the proportion of the total rubber components of the reinforced rubber composition A and the copolymer rubber B in the composition of the present invention is about 25 weight percent or more, preferably about 35 weight percent or more.

As the process for manufacturing a hose from the composition of the present invention, any known process for manufacturing a hose from a conventional rubber composition using ethylene-propylene-polyene copolymer rubber can be appropriately selected. For example, using a mixer such as a Banbury mixer at 90℃ to 150℃ for 4 to 10 minutes.
After kneading the reinforced rubber composition A, copolymer rubber B, antioxidant, inorganic filler, and processing aid for minutes, knead the reinforced rubber composition A, copolymer rubber B, antioxidant, inorganic filler, and processing aid using rolls such as oven rolls at a roll temperature of 40°C to 8°C.
At a temperature of 0°C, in the case of sulfur vulcanization, sulfur, vulcanization accelerator,
A vulcanization aid is additionally mixed, or in the case of peroxide vulcanization, an organic peroxide, a vulcanization aid, etc. are additionally mixed to prepare a sheet-like or ribbon-like compounded rubber. This compounded rubber is molded by an extruder into the shape of a hose or structure depending on the purpose of use, for example, a hollow tube when used for an inner tube, a ribbon or a sheet when used as a reinforcing layer, or a cover rubber. Further, the desired hose is processed and heated in a vulcanization bath heated to 130° C. to 220° C. for 1 minute to 60 minutes, whereby the hose can be manufactured by vulcanization.

The composition of the present invention can be used for any of the inner tube of the rubber hose, the cover rubber, or the reinforcing layer by varying the content of the short thermoplastic polymer fibers contained in the reinforced rubber composition A. In other words, it is possible to manufacture the desired rubber hose using only the composition of the present invention. It goes without saying that the composition of the present invention may be used for only one of the inner tube, the cover rubber, or the reinforcing layer of a rubber hose, or for two or more of them.

The attached drawings illustrate cross-sectional views of rubber hoses obtained from the composition of the present invention, and the rubber hose shown in FIG. The rubber hose has a reinforcing layer part 2 and an inner pipe part 1 on the inside and outside of the reinforcing layer part 2.
This is a rubber hose in which a cover rubber 3 and a cover rubber 3 are laminated in a cylindrical shape. Of course, the reinforcing layer portion may be laminated in two or more layers.

〔Effect of the invention〕

As mentioned above, the composition of the present invention is a new composition that imparts oil resistance, which was previously poor, to an ethylene/propylene copolymer rubber composition, and improves elasticity and heat aging resistance. If the inner pipe, reinforcing layer, and cover rubber of a rubber hose are all prepared with this composition, the conventional problem of poor adhesion between cotton cloth or chemical fiber cloth and rubber can be avoided, and a long-life rubber hose can be provided. became.

The composition of the present invention is suitably used for automobile radiator hoses and heater hoses, and suitably used for reinforcing layers and cover rubbers of fuel hoses and brake oil hoses. Furthermore, it is suitably used for industrial rubber hoses that require high elasticity, oil resistance, and heat aging resistance.

〔Example〕

Hereinafter, the composition of the present invention will be specifically explained with reference to Examples and Comparative Examples. On each side below, parts refer to parts by weight.

Reinforced rubber composition A (A
s, A, At, As) were prepared by the following method.

100 parts of EPDM in a Banbury mixer at 150°C.
1.0 part of an anti-aging agent (TSKURAK G-1 manufactured by Ohmukai Shinko Co., Ltd.) and 50 parts of 6-nylon were added and kneaded for 4 minutes. During this time, the temperature inside the mixer rose to 230°C, and the 6-nylon melted. Next, 2.25 parts of novolac-type phenol formaldehyde initial condensate was added and kneaded for 7 minutes, and then 0.225 parts of hexamethylenetetramine was added.
After kneading for 2.5 minutes to cause a graft reaction, the mixture was dumped.

The obtained five-wire object was extruded from an extruder using a die having an inner diameter of 2 mm, and then stretched at a draft ratio of 20.40 m/min. Furthermore, this stretched product was rolled at a roll gap of about 10 mm with a roll gap of 0.2 mm.
A reinforced rubber composition was obtained by rolling twice.

100 parts, 600 parts, 1, and 600 parts of the EPDM were added to 100 parts of the reinforced rubber composition A (this is 80 parts), and kneaded for 4 minutes in a Banbury mixer to obtain the reinforced rubber composition A + , A t and A t were obtained. Table 1 shows the amount of 6-nylon short fibers contained in the reinforced rubber composition A (Ao, AI, A2.As).

Table-1 Fiber content EPDM of reinforced rubber composition (A):
EP33 6-nylon made by Japan Synthetic Rubber A-Jun: 10
Table 2 shows the ethylene/propylene copolymer rubber B (B,, B□, B,) used in the Examples and Comparative Examples.

Table 2 Ethylene-propylene copolymer rubber reinforced rubber composition A has 6-
Although the nylon short fibers were already dispersed, the weight ratio of the grafted EPDM to the 6-nylon short fibers, that is, the grafting ratio, was calculated by the following method and measurement.

2g of reinforced rubber composition Ao and 200a+j of toluene! to 7
It was added at 0°C to dissolve the rubber component in 〇 into the reinforced rubber composition, and the resulting slurry was centrifuged at 50°C to separate into a solution portion and a precipitate portion. Repeat the above procedure 7 for the precipitated part.
After repeating this process several times, the precipitated portion was vacuum dried at 50°C to obtain a nylon fibrous material. This nylon fibrous material was dissolved in a mixed solvent of phenol and orthodichlorohenzene in a weight ratio of 6 to 6 (weight ratio), and the 1H nuclear magnetic resonance spectrum (
NMR) (internal standard tetramethylsilane)
From the MR chart, the molar ratio of 6-nylon and EPDM was determined by the cutting area method for each peak of the methyl group due to EPDM and the methylene group adjacent to the NH group due to 6-nylon, and the grafting rate was determined. It was calculated to be 7%.

In addition, the shape of the nylon fibrous material is approximately 2
00 pieces were observed using a scanning microscope at a magnification of 10,000 times. The fibrous material was an extremely thin short fibrous material with a circular cross section. The average diameter of the fibrous material was 0.2 μm, and the maximum diameter was 0.5 μm.

Further, the shortest fiber length of the fibrous material was 15 μm.

Examples 1 to 6, Comparative Examples 1 to 3 A compounded rubber was prepared from reinforced rubber composition A in Table 1 and copolymer rubber B in Table 2 according to the formulation table in Table 3, and then a vulcanizate was obtained. . That is, reinforcing rubber composition A, copolymer rubber B1 zinc white, stearic acid, Mistron paper talc, Geast H, and Yodoplast P were mixed in a Banbury mixer (BR type, manufactured by Kobe Steel, Ltd.) according to the formulation shown in Table 3. After kneading for 1 minute, antioxidant, vulcanizing agent, and vulcanization aid were added and kneaded for 15 minutes using 8 x 20 inch open rolls at a roll temperature of 60°C. The sheet was separated to obtain a compounded rubber sheet.

Using the above-mentioned compounded rubber, a rubber hose whose reinforcing layer 2 is made of cotton fabric as shown in Fig. 1 (described later) was prepared (vulcanization temperature: 180°C), and a No. 3 dumbbell according to JIS K 6301 was punched out from the vulcanized rubber part. Tensile stress M+, stress at break T, elongation at break Eb2 at 100% elongation at 25°C at a tensile speed of 500mm/l1lin according to the regulations.
was measured. Furthermore, the hardness H31 (JIS A) of the vulcanizate was measured according to JIS K 6301, and these values are shown in Table 4 as initial physical properties. Next, the above-mentioned No. 3 Dangel was replaced with Toyo Seiki's "TεST TUBE AGING T".
After being exposed to an air atmosphere at 160°C for 7 days using ESTERj, M
21 T b z +Eb2. “Measured 5K. 6M
16°, ΔT b , ΔE b + ΔH5 were calculated using the following formula to determine the TE index 1, which is considered to be a measure of heat aging resistance.

ΔH, = Hsz Hsl TE index = ΔT, × ΔE, /100 *R, D, A11en, J, Elas Lomers & P
lastics, 17, April, 150~
164 (1985) In addition, according to JIS K 6301, the width of the vulcanized rubber part is 2On+n+, the length is 50mm,
A test piece with a thickness of 2 cm was cut out and subjected to an immersion test. In the case of test oil (1 (lubricating oil), the test piece was immersed at 100°C for 70 hours, and the weight change rate before and after was determined.
In the case of A (fuel oil) as the test oil, the test piece was immersed at room temperature for 22 hours, and the weight change rate before and after was determined and used as a measure of oil resistance.

Table-3 Combination table■) 2-Mercabutobensimidazole (manufactured by Iriuchi Shinko Kagaku Co., Ltd.) 2) 2,2.4-)Dimethyl-1
, 2-Shihito ■ Kihan polymer (manufactured by Iriuchi Shinko Kagaku Co., Ltd.) 3) n-butyl-4,4-bis (tert-butylperoxy)valerate (manufactured by NOF Corporation) 4) p,p'-dibenzoylquinone di oxime
(Manufactured by Iriuchi Shinko Kagaku Co., Ltd. 5) Talc (Japan Mimato■
hmm ? [)6) IIAF h-nen 7 rakku
(manufactured by Tokai Carhon Co., Ltd.) 7) Higher fatty acid 1 liter (manufactured by Yodoyo Kagaku Co., Ltd.) Examples 7 to 10, Comparative Examples 4 to 6 In Example 3, as antioxidants and processing aids Table 5 The same operation as in Example 3 was performed except for using the formulation described in . The results are shown in Table-5.

Table-5 Z) Guma υ diinten hl R 3 E na J no J Gakutai Buki H Pito ti 1 = Yami υ husband 1'' In Example 4 of Rose i group, vulcanizing agent, vulcanization accelerator, and vulcanization aid Example 4 except that the formulations listed in Table 6 were used.
The same operation was performed. The results are shown in Table-6.

Margin below Table-6 7] 11 Korekago was heated to 160℃ for 40 minutes.

Ishieko In Example 3, the same operations as in Example 3 were performed except that ethylene-propylene-polyene copolymer rubber 1' was used instead of reinforced rubber composition A1, and the following results were obtained.

1) EP22 (manufactured by Japan Synthetic Rubber Company)/Example 17
, Comparative Example 8 Calosulfur sheets were prepared using the composition of the present invention and a chemical fiber cloth (6, nylon woven fabric) as the reinforcing layer, and a tensile test was conducted. The composition of the formulation is shown in Table-7.

Table 7 - The processing aids are the same as those in Table 3, and in the case of Example 17, the thickness of each of the inner tube, reinforcing layer, and cover rubber was 0.
A composite sheet was made by making sheets of 6 mm, 1.0 mm, and 0.6 mm and overlapping them, and in the case of Comparative Example 8, a sheet with a thickness of 1.1 mm was made for each of the inner tube and cover rubber.
A composite sheet was made by sandwiching a chemical fiber cloth in between. Each composite sheet was placed in a vulcanization mold with a machining diameter of 2 mm + 17), and vulcanization was performed at 180°C.

Each vulcanized sheet was punched out into a No. 3 dumbbell according to JIS K 6301, and heated at 25°C and at a tensile speed of 100mm/
The tensile stress M Io at 10% elongation and the strength and elongation at the time of breaking the reinforcing layer were measured at min. The results are shown in Table-8.

Table 8 From the above Examples and Comparative Examples, it can be seen that the rubber hose obtained from the composition of the present invention has high elasticity, excellent oil resistance, and excellent heat aging resistance.

[Brief explanation of drawings]

FIGS. 1 and 2 illustrate cross-sectional views of rubber hoses obtained from the composition of the present invention. 1: Inner tube part, 2: Reinforcement layer part, 3: Cover rubber. ]...Rubber 2...Reinforcement layer 3...Rubber 2nd cross section (rubber + fiber)

Claims (1)

[Claims] 1. A rubber composition for a hose that has high elasticity, oil resistance, and heat aging resistance and satisfies the following conditions (a) to (c). (a) Fine short fibrous material of thermoplastic polymer having an amide group (▲ mathematical formula, chemical formula, table, etc.) in the continuous phase consisting of ethylene-propylene-polyene copolymer rubber. are dispersed, and the thermoplastic polymer and the ethylene-propylene-polyene copolymer rubber are grafted via the novolac type phenolic resin at the interface of the short fibrous material, and the amount of the thermoplastic polymer is 2 to 100 parts by weight of copolymer rubber component
70 parts by weight of reinforced rubber composition A; (b) contains no ethylene-propylene copolymer rubber that does not contain a polyene component, or the molar ratio of ethylene and propylene (ethylene/propylene) is approximately 50/50 to about 90/10, and does not contain a polyene component, is mixed with reinforced rubber composition A.
(c) 0.5 parts by weight or more of antioxidant per 100 parts by weight of rubber components in the total amount of reinforced rubber composition A and copolymer rubber B; Contains an agent.