WO1999050349A1

WO1999050349A1 - Rubber composition for hose production and hose

Info

Publication number: WO1999050349A1
Application number: PCT/JP1999/001624
Authority: WO
Inventors: Mitsunori Abe; Daisuke Tsugawa
Original assignee: Nippon Zeon Co., Ltd.
Priority date: 1998-03-30
Filing date: 1999-03-30
Publication date: 1999-10-07
Also published as: JPH11343378A

Abstract

A rubber composition for producing an oil-resistant hose, which comprises an acrylic rubber obtained by polymerizing a monomer mixture comprising a fumaric monoester and an alkyl acrylate and a vulcanizing agent.

Description

Description Rubber composition for hose production and hose technology field

The present invention relates to a rubber composition for producing a hose and a hose produced by using the rubber composition. More specifically, the present invention relates to an acrylic rubber copolymerized with a monoester fumarate as a carboxyl group-containing monomer. The present invention relates to a rubber composition for producing an oil-resistant hose to be used, and an oil-resistant hose produced by using the rubber composition. Background technology

Oil-resistant hoses are generally manufactured by steam vulcanization after molding into a hose shape using acrylate copolymer rubber such as epoxy group-containing acrylic rubber or ethylene-acrylate copolymer rubber as raw material rubber. ing.

When a hose is produced by steam vulcanization after molding using a rubber composition containing an acryl rubber containing an epoxy group, there is a problem that the vulcanization properties are lower than when press vulcanizing the same rubber composition. On the other hand, when a composition containing ethylene-acrylate copolymer rubber as a main component is used, there is a problem in that, when extruded into the shape of a hose, the adhesive is severe, which hinders handling of the molded body before vulcanization. Was.

In order to solve such a problem, an oil-resistant hose using acryl rubber obtained by copolymerizing a monoalkyl maleate as a carboxyl group-containing monomer as a raw rubber is disclosed in Japanese Patent Application Laid-Open No. 6-95915. Have been. In this hose, the deterioration of vulcanization properties due to steam vulcanization and the adhesiveness during extrusion molding are improved.

However, hoses made of acryl rubber copolymerized with a monoalkyl maleate as a raw material rubber have a problem in that the pressure resistance, particularly after heat load, is insufficient.

JP-A-50-45031 discloses a butenedioic acid monoester such as maleic acid monoalkyl ester and acrylic acid alkyl ester, or acryl rubber obtained by copolymerizing these with ethylene. . These acrylic rubbers In the vulcanizable composition using the composition, scorch hardly occurs. However, the physical properties of the vulcanized product obtained by press vulcanizing the vulcanizable composition are not known, and the physical properties of the steam vulcanized product are not known. Disclosure of the invention

The present invention provides a rubber composition for producing an oil-resistant hose, in which a steam vulcanizate has the same vulcanizate properties as a press vulcanizate, and has a small decrease in pressure resistance after heat load. It is to provide a manufactured oil resistant hose.

The present inventors have conducted studies to achieve the above object in consideration of these known techniques, and as a result, as a carboxyl group-containing monomer, fumaric acid monoester is relatively coexistent with alkyl acrylate. The present inventors have found that the object can be achieved by using acryl rubber which can be polymerized and obtained, and have completed the present invention.

Thus, according to the present invention, there is provided a rubber composition for an oil-resistant hose, comprising an acryl rubber obtained by copolymerizing an alkyl acrylate and a monoester of fumaric acid, and a vulcanizing agent, and a rubber composition for a hose. An oil-resistant hose formed and vulcanized is provided. BEST MODE FOR CARRYING OUT THE INVENTION

The acryl rubber used in the present invention is obtained by polymerizing a monomer mixture containing a monoester of fumaric acid and an alkyl acrylate, and preferably polymerizing a monomer mixture containing these and an alkoxyalkyl acrylate. That is what we do.

Examples of the monoester of fumaric acid in the present invention include monomethyl fumarate, monoethyl fumarate, mono-n-propyl fumarate, monoisopropyl fumarate, mono-n-butyl fumarate, isobutyl fumarate, ter-butyl fumarate, ter-butyl fumarate, and fumarate Alkyl-based carbons such as mono-n-amyl fumarate, mono-n-hexyl fumarate, mono-n-heptyl fumarate, mono-n-hexyl fumarate, and mono- (2-ethylhexyl) fumarate Monoalkyl fumarate having a number of 1 to 10; monomethoxymethyl fumarate, monomethoxyl fumarate, monoethoxyxethyl fumarate, fumarate Monoalkoxyalkyl fumarate having an alkylene group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms, such as monomethoxybutyl acid, is exemplified. Of these, preferred are monomethyl fumarate, monoethyl fumarate, mono-n-propyl fumarate, mono-n-butyl fumarate, monomethoxymethyl fumarate, monomethoxethyl fumarate, and more preferably monoethyl fumarate and mono-n-fumarate —Butyl and the like.

In the present invention, the alkyl acrylate to be copolymerized with the fumaric acid monoester is not particularly limited, and those conventionally used in known acrylic rubbers can be used. For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-acrylate Amyl ester, n-hexyl acrylate, n-heptyl acrylate, acrylate (2-ethylhexyl) ester, n-acrylic acid octyl ester, η-nonyl acrylate, η-decyl acrylate, Examples include alkyl acrylates having an alkyl group having 1 to 10 carbon atoms, such as 2-cyanoethyl acrylate. Of these, acrylate ethyl ester or _η -butyl acrylate ester is preferred. These alkyl acrylates can be used alone or in combination of two or more.

The alkoxyalkyl acrylate used together with the alkyl acrylate is not particularly limited, and those used in conventionally known acrylic rubbers can be used. For example, methacryloxymethyl acrylate, ethoxyquin methyl acrylate, 2-methoxyethyl acrylate, 2-ethoxy ethoxylate, 2-butoxyethyl acrylate, etc. An alkoxyalkyl acrylate having an alkylene group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms is exemplified. Among them, acrylic acid 2-methoxethyl ester and acrylic acid 2-ethoxyethyl ester are preferred. These alkoxyalkyl acrylates can be used alone or in combination of two or more. If necessary, a monomer copolymerizable with the above monomer can be used in the present invention. Examples of such a monomer include a, / 3-unsaturated nitrile monomer such as acrylonitrile and methacrylonitrile. Α-olefins such as ethylene and propylene; aromatic vinyl monomers such as styrene and α-methylstyrene; vinyls such as vinyl chloride, vinylidene chloride, vinyl acetate, ethyl vinyl ether, and butyl vinyl ether Other monomers that are derivatives of acrylic acid and methacrylic acid, such as alkoxyalkyl methacrylate, furfuryl acrylate, acrylamide, etc .; monomers such as isoprene, butadiene, chloroprene, piperylene, etc. Conjugated diene monomer: dicyclopentene, norbornene, ethylidene norbo Non-conjugated diene monomers such as nene, hexadiene, norbornadiene; polyfunctional such as divinylbenzene, ethylene glycol diacrylate, propylene glycol diacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate Monomers. These can be used alone or in combination of two or more.

The acryl rubber used in the present invention can be obtained by radical polymerization of the above monomer in the same manner as ordinary polymerization of acryl rubber. In the present invention, polymerization forms such as emulsion polymerization, solution polymerization, and suspension polymerization, polymerization systems such as batch system and continuous system, polymerization conditions such as polymerization temperature, and recovery methods are not particularly limited. It may be.

The proportion of each monomer in the monomer mixture at the time of producing the acryl rubber used in the present invention is appropriately determined according to the characteristics required for a hose using the acryl rubber, and is not particularly limited. The proportion of the fumaric acid monoester in the monomer mixture is preferably from 0.1 to 40% by weight, more preferably from 0.2 to 20% by weight, particularly preferably from 0.5 to 10% by weight. . The proportion of alkyl acrylate in the monomer mixture is preferably from 10 to 99.9% by weight, more preferably from 50 to 97.8% by weight, particularly preferably from 70 to 94.5% by weight. %. When the alkoxyalkyl acrylate is copolymerized, the proportion of the alkoxyalkyl acrylate in the monomer mixture is preferably 0 to 50% by weight, more preferably 2 to 30% by weight, particularly preferably 2 to 30% by weight. Preferably it is 5 to 20% by weight. Can be copolymerized with these monomers if necessary κ

The monomer can be used within a range that does not impair the inherent properties of acryl rubber.

The unit amount of each monomer in the acryl rubber used in the present invention thus obtained coincides with the amount of each monomer used in the above-mentioned polymerization (the amount charged during the polymerization).

The acrylic rubber used in the present invention has a viscosity of ML (ML _{1 + 4} , 100 ° C), preferably from 10 to 150, more preferably from 15 to 100, and particularly preferably from 15 to 100. Preferably it is 20 to 60.

The amount of the fumaric acid monoester unit in the acryl rubber used in the present invention is preferably 0.0005 to 0.06 mol, more preferably 0 mol, based on the amount of carboxyl groups (ephr) in 100 g of the acryl rubber. 0.003 to 0.020 mol, particularly preferably 0.05 to 0.010 mol. If the amount of the fumaric acid monoester unit is too small, vulcanization becomes insufficient, and it is difficult to use as a vulcanized rubber. On the other hand, if the amount of fumaric acid monoester unit is too large, vulcanization will be excessive, elongation will be reduced, and strength and heat resistance will be insufficient.

The rubber composition for producing a hose of the present invention is obtained by blending a vulcanizing agent with the above acryl rubber.

The term “vulcanization” is originally used when vulcanizing an unsaturated rubber such as a gen-based rubber with sulfur or a sulfur-donating compound as a vulcanizing agent. In the case of cross-linking other organic peroxides and rubbers having no unsaturated bond using a bridging agent specific to them, these cross-linking agents are called vulcanizing agents, and cross-linking is called vulcanization. Therefore, also in the present invention, the crosslinking agent is referred to as a vulcanizing agent, and the crosslinking is referred to as vulcanizing.

In the present invention, any conventionally known vulcanizing agent used for vulcanizing a carboxyl group-containing acryl rubber can be used, and is not particularly limited.

Preferred vulcanizing agents include, for example, primary amines such as polyvalent aliphatic primary amines and polyvalent aromatic primary amines and derivatives thereof, and compounds containing a polyhydrazide group. Can be

Examples of polyvalent aliphatic primary amines and derivatives thereof include hexamethylene diamine, hexamethylene diamine carbamate, tetramethylene pentamine, and g

Xamethylene diamine-cinnamaldehyde condensate and hexamethylene diamine-dibenzoate salt and the like. Examples of aromatic primary amines include 4, 4'-methylene dianiline, 4 , 4'-diaminodiphenyl ether, m-phenylenediamine, p-phenylenediamine, 4,4'-methylenebis (o-chloroaniline) and the like. Of these, hexamethylene diamine carbamate, hexamethylene diamine-cinnam aldehyde condensate, 4,4'-methylene dianiline, and 4,4 'diamino diphenyl ether are preferred. These can be used alone or in combination of two or more.

Examples of polyhydrazide group-containing compounds include, for example, isophthalic acid dihydrazide, terephthalic acid dihydrazide, phthalic acid dihydrazide, 2,6-dinaphthalenedene diluphthalide, ruponic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, azidipine Reaction products of carboxylic acids such as aliphatic carboxylic acids and aromatic carboxylic acids such as acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide and fumaric acid hydrazide with hydrazine. These can be used alone or in combination of two or more.

Usually, a vulcanizing agent is often used together with a vulcanization accelerator, and the use of a vulcanization accelerator is also desirable in the present invention.

Examples of the vulcanization accelerator include (1) alkali metal salts and alkali metal hydroxides of inorganic weak acids (eg, sodium hydroxide, sodium carbonate, potassium hydroxide, sodium hydrogen carbonate, etc.), (2) organic weak acids Alkali metal salts, alkali metal alcoholates and phenolates (eg, sodium stearate, potassium stearate, sodium laurate, sodium benzoate, sodium ethoxide, etc.); Penium salts and quaternary phosphonium salts, hydroxides, alcoholates, phenolates, etc. (tetrabutylammonium hydroxide, tetramethylammonium bromide, benzyltriphenylphosphonium chloride, tetramethyl chloride) Butyl ammonium methoxide, octadecyl trimethyl ammonium (4) Tertiary amines (eg, triethylenediamine, N, N, Ν ', Ν'-tetramethyl-1,4-butanediamine, Ν, Ν, Ν', N '-Tetramethyl-1,2-diaminophenol, Ν, Ν-dimethylaminoethanol, etc.), (5) n

Guanidines (diphenylguanidine, di-O-tolylguanidine, tetramethylguanidine, dibutyldanidine, etc.), (6) Heterocyclic tertiary amines (imidazole, pyridine, quinoline, etc.) Is mentioned. These can be used alone or in combination of two or more.

The amount of the vulcanizing agent is not particularly limited, but is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the acrylic rubber. If the amount of the vulcanizing agent is too small, it is difficult to obtain a vulcanizate having satisfactory tensile strength due to insufficient vulcanization, and if the amount of the vulcanizing agent is too large, the vulcanized product is hard. Too much, and the decrease in elongation becomes large.

The amount of the vulcanizing agent used is a general guide. More precisely, the amount of the functional group in the vulcanizing agent used per 100 g of the acrylic rubber is preferably 0.000. The amount of the vulcanizing agent is adjusted so as to be 0.2 to 0.1 mol, more preferably 0.005 to 0.035 mol, and particularly preferably 0.02 to 0.02 mol. Decide.

The amount of the vulcanization accelerator used is preferably from 0.1 to 20 parts by weight, more preferably from 0.2 to 10 parts by weight, particularly preferably from 0 to 100 parts by weight, per 100 parts by weight of the acryl rubber of the present invention. 4 to 5 parts by weight. If the amount of the vulcanization accelerator is too small, it is difficult to obtain a vulcanizate with insufficient vulcanization and satisfactory tensile strength, and if the amount of the vulcanization accelerator is too large, the vulcanization properties may be reduced. The improvement effect is small and lacks processing stability.

The rubber composition for producing an oil-resistant hose of the present invention can be produced by mixing the acrylic rubber and the vulcanizing agent together with other compounding agents, if necessary. Mixing is usually performed by kneading using a mixer such as a roll, a Banbury or an internal mixer.

Other compounding agents include, for example, reinforcing materials, fillers, anti-aging agents, antioxidants, light stabilizers, anti-scorch agents, crosslinking retarders, plasticizers, processing aids, lubricants, adhesives, lubricants , A flame retardant, a fungicide, an antistatic agent, a coloring agent, and the like. In the present invention, the type and amount of these compounding agents are not particularly limited, and the characteristics required for an oil-resistant hose are not limited. It can be determined appropriately depending on the situation.

In the present invention, if necessary, other rubber components or resin components are mixed with the above-mentioned acryl rubber as long as the effects of the present invention are not impaired. _Q

be able to. Other rubber components include, for example, acrylic rubber other than the above acrylic rubber, ethylene-acrylate copolymer rubber, olefin rubber such as EPDM, natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene copolymer Rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, vinyl chloride-based elastomer, polyester-based elastomer, polyamide-based elastomer, polyurethane-based elastomer, polysiloxane-based elastomer, and the like. In particular, the use of ethylene acrylate copolymer rubber is preferred. By mixing this copolymer rubber with the above-mentioned acryl rubber, a vulcanizate having a very small strength characteristic and a small change in elongation after heat aging can be obtained.

Ethylene monoacrylate copolymer rubber is obtained by copolymerizing ethylene and at least one of the above-mentioned alkyl acrylates or at least one of the above-mentioned alkoxy acrylates, and a monomer for a crosslinking site. This is the rubber obtained. The proportion of each of these monomers used in the production of the copolymer rubber is not particularly limited. The ethylene is preferably 20 to 75% by weight, more preferably 30 to 65% by weight, and still more preferably. 40 to 55% by weight, preferably 0 to 30% by weight of the crosslinked site monomer, more preferably 0.5 to 15% by weight, still more preferably 3 to 5% by weight, acrylic acid It is a copolymer rubber obtained by copolymerizing a monomer mixture with the remaining alkyl ester. In this case, the alkyl acrylate is preferably methyl acrylate or ethyl acrylate. When the copolymer rubber is cross-linked with a cross-linking agent different from the acryl rubber used in the present invention, various conventionally known cross-linked site monomers can be used, and there is no particular limitation. In the case of crosslinking with the same crosslinking agent as the acryl rubber used in the present invention, butenedioic acid monoesters such as monoalkyl maleate, monoalkoxyalkyl maleate, monoalkyl fumarate and monoalkoxyalkyl fumarate are preferred. The monoester in this case is the same as the above-mentioned monoester of fumaric acid monoester. The proportions of these crosslinking site monomers used are the same as those used in the acrylic rubber of the present invention.

The Mooney viscosity of the ethylene-acrylate copolymer rubber is the same as that of the acryl rubber used in the present invention. When the acryl rubber and the ethylene-acrylate copolymer rubber used in the present invention are mixed and used, the acryl rubber is preferably 50 to 90% by weight, more preferably 70 to 85% by weight. The copolymer rubber is preferably used in a mixture of 10 to 50% by weight, more preferably 15 to 30% by weight.

Depending on the purpose of mixing the ethylene-acrylate copolymer rubber, it may not be necessary to cross-link the copolymer rubber. In such a case, a monomer for a bridge site is copolymerized as the copolymer rubber. The copolymer rubber which has not been used can also be used.

When the ethylene-acrylate copolymer rubber is cross-linked, it can be cross-linked using a cross-linking agent different from the acrylic rubber used in the present invention, but is preferably co-cross-linked with the same cross-linking agent as the acryl rubber. In this case, the amounts of the cross-linking agent and the cross-linking accelerator used are appropriately adjusted so as to satisfy the performance required for the oil-resistant rubber hose. A method for producing a hose using the rubber composition for producing a hose of the present invention may be in accordance with a conventionally known method for producing a hose, and is not particularly limited. Also, the structure of the hose is not particularly limited, and may be, for example, a fiber coating, a thread core, or a laminate with another rubber or resin.

For example, a hose is formed by extruding a rubber composition into a hose shape using an extruder, performing primary vulcanization by steam vulcanization in a vulcanizer, and then performing secondary vulcanization under hot air in an oven. Manufactured in.

The hose of the present invention can be used, for example, as an oil-resistant hose such as an automotive fuel hose, an automotive ATF hose, and an educt hose.

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, parts and percentages are by weight unless otherwise specified.

Examples 1 to 7, Comparative Examples 1 to: L 6

The acryl rubber copolymerized with fumaric acid monoester used in the present invention and the acryl rubber of Comparative Example were produced by ordinary emulsion polymerization. Table 1 shows the monomer composition of each of the acrylic rubbers and the amount of carboxylic acid groups in the rubbers. Single summer body Acryl rubber

A Β c

Acryzole acid 37.3 39.5 39.5

Η-Butyl acrylate 44.5 44.4

T ノ \ ン \ レ H¾ —, r ■ =? = ■ ノ / し 14.0 14.8 14.8

Mono η-butyl maleate 6.8 0 0

Monoethyl itaconate 0 1.2 0

Monoethyl fumarate 0 0 1.2

Amount of bound carboxyl groups

(10- ³ ephr) 7.4 7.9 7.7

Polymer viscosity

(ML _{1 + 4} , 100 ° C) 40.8 43.0 45.5 According to the compounding recipe shown in Tables 2 to 5, each compounding agent other than the vulcanizing agent and the vulcanization accelerator and each acryl rubber, and Examples 3 and 4 In Examples 7 and 8 and Comparative Examples 58 and 1316, ethylene-acrylate copolymer rubber was further mixed with a small Banbury (0.8 liter volume), and a vulcanizing agent and a vulcanizing agent were added to the obtained mixture. The sulfur accelerator was mixed and kneaded with 6 inches to prepare a vulcanizable rubber composition.

Each vulcanizable rubber composition is press-vulcanized (primary vulcanization: 160 ° C, 30 minutes) to obtain a vulcanized sheet having a thickness of 2 mm, which is then secondary vulcanized with heated air ( (170 ° C, 4 hours). The vulcanization conditions for steam vulcanization in a vulcanizer as the primary vulcanization are the same as the above-mentioned primary vulcanization conditions.

Using this vulcanized sheet, the tensile strength, elongation, and 100% tensile stress were measured according to JISK6251, and the hardness was measured according to JISK6253. The heat aging property was measured in accordance with JISK 6257, and was expressed as the rate of change after heat load (leaved at 150 ° C for 70 hours) before heat load. The results are shown in Table 25. Table 2

Note) Common to Tables 2 to 5

(1) DuPont Vam ac G

(Copolymer of about 4648% of ethylene, about 5048% of methyl acrylate, about 3.54.5% of monomethyl maleate)

(2) Tokai Rikibon Co., Ltd., system 1 1 6

(3) Dainippon Ink & Chemicals, Grec G 82 05

(4) 4, 4 'diaminodiphenyl ether

(5) DuPont, Diak No. 3 (NN'-discinnaden)

16-hexanediamine) Table 3

Yuroku £ ||

Arrow μ ¾¾ μ μμ ± 6 Ell £ μϋR 军 ma 义 6 WEl'll o o

D 4 1 o Acrynolecom type C A B c A B Formulation

Acryl rubber 80 80 80 80 80 80 Ethylene monoacrylate

Copolymer rubber (1) 20 20 20 20 20 20

MAF car phone hook (2) 60 60 60 60 60 60

, "Sift

Stainless steel, linoleic acid 1 1 1 1 1 I Lubricant (3) 2 2 2 2 2 2 IJDPE (4) 0.44 0.42 0, 45

Power!] Sulfurizing agent DK3 (5) 1.53 1.47 1.56 n-o-trinolecanno 2 2 2 1 1 1, cross-linking method Nores Breath Breath Breath Breath Breath

Tree t 问 tree + direction tree 问 tree f 问 tree 1 问 tree 常

Tensile strength (MPa) 12.1 11.2 11.9 14.5 12.1 13.7 Elongation (%) 210 210 210 220 260 240

100% tensile stress (Mpa) 6.9 6.2 5.8 7.6 5.5 6.0 Hardness (JIS A) 71 72 70 72 74 71 Thermal aging of crosslinked product

Bow I Change in tensile strength (%)-10 -16-23 -12 -11 -17 Change in elongation (%)-2-3-25 -1 -15 -15

Table 4

it Kil Ell 夹 / iS K

Example ratio? Father Hihisa Father 夹 Example Hibitsu Father £ L Skewer Father c

0 9 10 0 I I 1 Type of Acrylcom C A B C A B Formulation

Acryl rubber 100 00 100 100 100 100 Ethylene acrylate

Copolymer rubber (1) ―

MAF carbon black (2) 60 60 60 60 60 60 Filling, linoleic acid 1 1 1 1 1 1 Lubricant (3) 2 2 2 2 2 2 Caro sulfurizer DPE (4) 0.44 0.42 0.45

Caro sulfuric acid DK3 (5) 1.53 1.47 1.56 0-tri-lequalene 2 2 2 1 1 1 Primary cross-linking method Stee-stee-stee-stee-stee-steam vulcanized Physical properties

Tensile strength (MPa) 11.5 10.7 11.0 14.5 12.1 13.7 Elongation (%) 200 200 210 220 260 240

100% tensile stress (Mpa) 6.2 5.5 5.8 7.6 5.5 6.0 Hardness (JIS A) 65 66 70 72 74 71 Heat aging of crosslinked product

Tensile strength change rate (%)-5-11 -23 -12 -11 -17 Elongation change rate (%) 1 6 -12-25 1 1 -15-15

Table 5

As shown in Tables 2-5, when acryl rubber obtained by copolymerizing fumaric acid monoester is used, regardless of the primary vulcanization method (press vulcanization, steam vulcanization), a slow heat load or severe heat treatment is applied. However, even after being subjected to a heat load, the rate of change of the bow I tensile strength was remarkably improved as compared with the case where the acrylic rubber copolymerized with a carboxyl group-containing monomer other than the monoester fumarate of the comparative example was used. ing.

Using the rubber compositions of the respective Examples and Comparative Examples, hoses were produced by performing primary vulcanization by steam vulcanization and secondary vulcanization in an oven. All of the hoses made of the rubber composition of the comparative example showed a large decrease in the tensile strength after heat load as compared to the tensile strength in the state, which hindered use, whereas the hose of the present invention It was confirmed that the hose of the present invention under normal conditions and after heat load had excellent tensile strength.

Also, in the present invention, the ethylene rubber is used as It can be seen that by blending the acrylate copolymer rubber, a vulcanizate having a high tensile strength and an excellent performance with a very small elongation change after thermal aging can be obtained. Industrial applicability

When the rubber composition for manufacturing a hose of the present invention is used, the decrease in strength after heat load is remarkably small even in the case of steam vulcanization, as in the case of press vulcanization or vulcanization under heated air. A hose with excellent strength retention and excellent oil resistance can be obtained. The hose of the present invention thus manufactured is suitable for an oil-resistant hose for transferring various control oils such as ATF oil transfer and power steering.

Claims

The scope of the claims

1. A rubber composition for hose production containing an acrylic rubber obtained by polymerizing a monomer mixture containing a monoester of fumaric acid and an alkyl acrylate and a vulcanizing agent.

2. The rubber composition according to claim 1, wherein the acrylic rubber is obtained by copolymerizing a monomer mixture containing an alkyl acrylate, a monoester of fumaric acid, and an alkoxyalkyl acrylate.

3. The fumaric acid monoester is a monoalkyl fumarate having an alkyl group having 1 to 10 carbon atoms, or a monofumarate having an alkylene group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms. 3. The rubber composition according to claim 1, which is an alkoxyalkyl ester.

4. The rubber composition according to any one of claims 1 to 3, wherein the alkyl acrylate is an alkyl acrylate having an alkyl group having 1 to 10 carbon atoms.

5. The rubber composition according to any one of claims 1 to 4, wherein the alkoxyalkyl acrylate has an alkylene group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms. .

6. The rubber composition according to any one of claims 1 to 5, wherein the acrylic rubber is obtained by polymerizing a monomer mixture containing 0.1 to 40% by weight of fumaric acid monoester.

7. The rubber composition according to claim 6, wherein the monomer mixture contains 10 to 99.9% by weight of an alkyl acrylate.

8. The rubber composition according to claim 6, wherein the monomer mixture acryl rubber contains 0 to 50% by weight of an alkoxyalkyl acrylate.

9. The rubber composition according to any one of claims 1 to 8, wherein the acrylic rubber has 0.0005 to 0.06 mol of carboxyl groups per 100 g.

10. The rubber composition according to any one of claims 1 to 9, wherein the acryl rubber has a Mooney viscosity of 10 to 150.

11. The rubber composition according to any one of claims 1 to 10, wherein the vulcanizing agent is a polyvalent primary amine or a compound containing a polyhydrazide group.

12. The rubber composition according to any one of claims 1 to 11, comprising an ethylene acrylate copolymer rubber.

13. A hose produced by molding and vulcanizing the rubber composition according to any one of claims 1 to 11.