JP2001019804A - Rubber composition for hose and hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for hoses having the excellent resistance to peameation of fuel oil and excellent ozone resistance and a hose suitably used fuel oils. SOLUTION: This rubber composition for hoses contains an epihalohydrin rubber (A) comprising 40 to 92 mol% ephihalodydrin monomer unit, 8 to 20 mol% unsaturated epoxide monomer unit and 0 to 40 mol% other monomer units, a nitrile rubber (B) and at least one crosslinking agent (C) chosen from a crosslinking agent for epihalohydrin rubber and a crosslinking agent for nitrile rubber, wherein, the ratio of component (A) is 20 to 70 wt.% against the total amount of components (A) and (B). A hose has a layer prepared by crosslinking this composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a hose and a hose having a layer formed by crosslinking the same, and more particularly to a hose containing a specific epihalohydrin rubber, a nitrile rubber and a specific crosslinking agent. The present invention relates to a rubber composition for hoses having excellent fuel oil permeability and ozone resistance, and a hose having a layer formed by crosslinking the rubber composition.

[0002]

2. Description of the Related Art Nitrile rubber is widely used as a material for various hoses because of its excellent balance between fuel oil permeability and cold resistance. Above all, it is widely used as a material for fuel oil hoses for automobiles that require fuel oil permeability resistance that suppresses the emission of fuel oil such as gasoline into the atmosphere. However, nitrile rubber is not necessarily sufficient in terms of ozone resistance (resistance to hose deterioration caused by ozone in the air) required for fuel oil hoses of recent automobiles.

Therefore, as a method for improving the ozone resistance of the nitrile rubber, a method of blending a vinyl chloride resin (PVC) with the nitrile rubber has been awarded. However, in recent years, incineration of PVC and the like has resulted in incineration. There is a trend to refrain from using PVC because dioxin is generated depending on the temperature.

As another method, Japanese Patent Publication No. 50-403 is disclosed.
No. 2 discloses a blend of an epihalohydrin rubber with a nitrile rubber, using an organic polysulfide such as tetramethylthiuram disulfide, 2-mercaptoimidazoline or thiourea, and an oxide such as magnesium or lead. A method for improving the ozone resistance of a nitrile rubber is disclosed. However, even with this method, it has not been possible to satisfy the high level of ozone resistance required with the recent maintenance-free automobile parts.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hose excellent in fuel oil permeability and ozone resistance and a rubber composition therefor.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have blended a specific epihalohydrin rubber with a nitrile rubber at a specific ratio to form a specific cross-linked rubber. It has been found that a rubber crosslinked product having excellent fuel oil permeability and ozone resistance can be obtained by using the agent, and the present invention has been completed based on the findings.

Thus, according to the present invention, 40 to 92 mol% of an epihalohydrin monomer unit, 8 to 20 mol% of an unsaturated epoxide monomer unit and 0 to 4 other monomer units.
An epihalohydrin rubber (A) comprising 0 mol%, a nitrile rubber (B), and at least one crosslinking agent (C) selected from an epihalohydrin rubber crosslinking agent and a nitrile rubber crosslinking agent. A rubber composition,
The ratio of (A) to the total amount of (A) and (B) is 20 to 70
Provided are a rubber composition for a hose, which is a weight percentage, and a hose having a layer obtained by crosslinking the rubber composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Rubber composition for hose The rubber composition for hose of the present invention comprises, as described above, an epihalohydrin rubber (A), a nitrile rubber (B),
It is a rubber composition containing a crosslinking agent (C).

Epihalohydrin rubber (A) The epihalohydrin rubber (A) used in the present invention comprises:
A copolymer containing at least an epihalohydrin monomer unit and an unsaturated epoxide monomer unit. Specific examples of the epihalohydrin monomer for constituting the epihalohydrin monomer unit include epichlorohydrin, epibromohydrin, β-methylepichlorohydrin and the like. Epihalohydrin monomers may be used in combination of two or more. Among them, epichlorohydrin is preferred from the viewpoint of easy availability.

The content of the epihalohydrin monomer unit in the epihalohydrin rubber (A) is 40 mol% with respect to all the monomer units constituting the epihalohydrin rubber (the same applies to the following). Preferably it is 60 mol%, and the upper limit is 92 mol%, preferably 90 mol%.
When the content of the epihalohydrin monomer unit is too small, the fuel oil permeability decreases, and when it is too large, the ozone resistance decreases.

The monomers for constituting the unsaturated epoxide monomer unit include diene monoepoxides, α, β-
Glycidyl ethers of ethylenically unsaturated compounds, glycidyl esters of α, β-ethylenically unsaturated compounds containing a carboxylic acid group, and the like can be mentioned.

As diene monoepoxides, butadiene monoepoxide, chloroprene monoepoxide,
Examples thereof include 4,5-epoxy-2-pentene, epoxy-1-vinylcyclohexene, and 1,2-epoxy-5,9-cyclododecadien.

The glycidyl ethers of the α, β-ethylenically unsaturated compound include vinyl glycidyl ether,
Allyl glycidyl ether, vinylcyclohexane glycidyl ether, o-allylphenyl glycidyl ether and the like can be mentioned.

The glycidyl esters of carboxylic acid-containing α, β-ethylenically unsaturated compounds include glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, glycidyl-4-heptate, glycidyl sorbate, glycidyl linoleate, and 3-cyclohexene carboxylic acid. Glycidyl ester of acid, 4-methyl-3
A glycidyl ester of cyclohexene carboxylic acid;

These unsaturated epoxide monomers may be used in combination of two or more. Among these,
Allyl glycidyl ether is preferred from the viewpoint of easy availability.

The content of the unsaturated epoxide monomer unit is as follows:
The lower limit is 8 mol%, preferably 10 mol%, and the upper limit is 20 mol%, preferably 18 mol%. When the content of the unsaturated epoxide monomer unit is too small, the ozone resistance is reduced, and when it is too large, the fuel oil permeability and the ozone resistance are reduced.

The epihalohydrin rubber (A) used in the present invention may contain other monomer units. Examples of the monomer constituting the monomer unit include an alkylene oxide monomer. Examples of the alkylene oxide monomer include ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxy-isobutane, 2,3-epoxybutane, 1,2-epoxyhexane, 1,2-epoxyoctane, , 2-epoxydecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane, 1,2-epoxyoctadecane,
1,2-epoxyeicosane, 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,2-
Epoxy cyclododecane, styrene oxide and the like are mentioned, and ethylene oxide, propylene oxide and the like are preferable.

The upper limit of the content of other monomer units in the epihalohydrin (A) is 40 mol%, preferably 35 mol%.
If the content is excessively high, the fuel oil permeability and ozone resistance decrease.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the epihalohydrin rubber is not particularly limited, but is preferably 30 or more, more preferably 40 or more, preferably 140 or less, more preferably 90 or less. If the Mooney viscosity is too high or too low, the processability will decrease.

Nitrile rubber (B) The nitrile rubber (B) used in the present invention is a polymer containing an α, β-ethylenically unsaturated nitrile monomer unit and a conjugated diene monomer unit. . The α, β-ethylenically unsaturated nitrile monomer is not particularly limited, but specific examples thereof include acrylonitrile and methacrylonitrile. Among them, acrylonitrile is preferable from the viewpoint of fuel oil resistance.

The content of the α, β-ethylenically unsaturated nitrile monomer unit in the nitrile rubber (A) is usually 20.
To 55% by weight, and may be appropriately adjusted according to the fuel oil permeability resistance and the cold resistance required for the hose.

The conjugated diene monomer used in the nitrile rubber (B) is not particularly limited, but specific examples thereof include 1,3-butadiene, 2-methyl-1,3-butadiene and 1,3-pentadiene. , 2-chloro-1,3-butadiene and the like. Among them, 1,3-butadiene is preferred from the viewpoint of cold resistance. The content of the conjugated diene monomer unit is usually 45% by weight or more.

The nitrile rubber used in the present invention contains other monomer units, for example, α-olefin monomer,
α, β-ethylenically unsaturated carboxylic acid monomer, α, β-
Ethylenically unsaturated carboxylic acid ester monomer, α, β-
Ethylenically unsaturated carboxylic acid amide monomer, vinyl aromatic monomer, carboxylic acid ester monomer of α, β-ethylenically unsaturated alcohol, α, β-ethylenically unsaturated ketone monomer, α, A monomer unit composed of a β-ethylenically unsaturated ether monomer or the like may be contained.

Examples of the α-olefin monomer include ethylene, propylene, 1-butene and the like.

Examples of the α, β-ethylenically unsaturated carboxylic acid monomers include monocarboxylic acids such as acrylic acid and methacrylic acid; polycarboxylic acids such as maleic acid, fumaric acid and itaconic acid; monobutyl fumarate And monoesters of polycarboxylic acids such as monobutyl maleate and monoethyl itaconate.

The α, β-ethylenically unsaturated carboxylic acid ester monomers include alkyl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and lauryl methacrylate; methoxyethyl acrylate, methoxyethoxyethyl acrylate Alkoxy-substituted alkyl esters such as cyanomethyl acrylate, 2-cyanoethyl acrylate, 2-ethyl-6-cyanohexyl acrylate; 2-substituted alkyl esters;
Hydroxy-substituted alkyl esters such as hydroxyethyl acrylate and 2-hydroxyethyl methacrylate; epoxy-substituted alkyl esters such as glycidyl acrylate and glycidyl methacrylate; N, N ′
Amino-substituted alkyl esters such as dimethylaminoethyl acrylate; halogen-substituted alkyl esters such as 1,1,1-trifluoroethyl acrylate;
Complete esters of polyvalent carboxylic acids such as maleic acid diethyl ester, fumaric acid dibutyl ester and itaconic acid dibutyl ester; and the like.

Examples of the α, β-ethylenically unsaturated carboxylic acid amide monomers include acrylamide, methacrylamide, N, N′-dimethylacrylamide, N-butoxymethylacrylamide, N-butoxymethylmethacrylamide, N-methylolacrylamide , N, N'-
Dimethylolacrylamide and the like.

As the vinyl aromatic monomer, styrene,
α-methylstyrene, ethylstyrene, butylstyrene, phenylstyrene, vinylnaphthalene, vinylanthracene, butoxystyrene, phenoxystyrene, vinylbenzoic acid, vinylsalicylic acid, aminostyrene, cyanostyrene, nitrostyrene, chlorostyrene, chloromethylstyrene, etc. No.

Examples of the carboxylic acid ester monomers of α, β-ethylenically unsaturated alcohol include vinyl acetate, isopropenyl acetate, vinyl benzoate, vinyl chloroacetate and the like.

Examples of the α, β-ethylenically unsaturated ketone monomer include vinyl ethyl ketone and vinyl phenyl ketone.

Examples of the α, β-ethylenically unsaturated ether monomer include vinyl methyl ether, vinyl butyl ether, vinyl-2-ethylhexyl ether, vinyl phenyl ether and the like. In addition to the above, monomers such as vinyl chloride, vinylidene chloride, and vinylpyridine are exemplified.

The Mooney viscosity of the nitrile rubber (B) (M
(L _{1 + 4} , 100 ° C.) is not particularly limited, but is preferably 25 or more, more preferably 35 or more, particularly preferably 40 or more, preferably 140 or less, and more preferably 1 or less.
It is 20 or less, particularly preferably 100 or less. If the Mooney viscosity is too high or too low, the processability will decrease.

In the rubber composition for hoses of the present invention, the lower limit of the ratio of the epihalohydrin rubber (A) to the total amount of the epihalohydrin rubber (A) and the nitrile rubber (B) is 20% by weight, preferably 25% by weight. % By weight, more preferably 40% by weight, and the upper limit is 70% by weight, preferably 65% by weight, more preferably 60% by weight. If the proportion of the epihalohydrin rubber (A) is too small, the ozone resistance is reduced. If the proportion is too large, the ozone resistance is reduced and the rubber hardness after a long time under high temperature conditions is reduced. Failure occurs.

The rubber composition for a hose of the present invention may be an unsaturated rubber such as isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber or the like; butyl rubber, ethylene or the like, as long as the effects of the present invention are not substantially impaired. -Propylene rubber, ethylene-acrylic rubber,
Highly saturated rubbers such as acrylic rubber, chlorosulfonated polyethylene, chlorinated polyethylene, hydrogenated nitrile rubber, silicon rubber, and fluorine rubber may be contained. The blending amount of these rubbers is usually about 0 to 20 parts by weight based on 100 parts by weight of the total of the epihalohydrin rubber (A) and the nitrile rubber (B).

Crosslinking Agent (C) The rubber composition for a hose of the present invention contains, as an essential component, at least one crosslinking agent (C) selected from a crosslinking agent for epihalohydrin rubber and a crosslinking agent for nitrile rubber. . In order to exhibit the effects of the present invention, any one of the crosslinking agents may be contained, but it is preferable to contain a nitrile rubber crosslinking agent in terms of exhibiting more excellent fuel oil permeability, When an epihalohydrin rubber cross-linking agent and a nitrile rubber cross-linking agent are used in combination, they exhibit particularly excellent performance in terms of fuel oil permeability and ozone resistance.

Crosslinking Agent for Epihalohydrin Rubber Examples of crosslinking agents for epihalohydrin rubber include thioureas, triazines, quinoxalines, amines and the like. Among them, thioureas and triazines,
It is preferable in terms of ozone resistance and crosslinking properties.

The thioureas include ethylene thiourea, diethyl thiourea, dibutyl thiourea, dilauryl thiourea, trimethyl thiourea and diphenyl thiourea. Among them, ethylene thiourea is preferable.

Triazines are triazine compounds substituted with at least two mercapto groups and have 1 carbon atom.
It may have a substituent such as an alkyl group of 10 to 10, an alkylamino group, a dialkylamino group and the like. Triazines include 2,4,6-trimercapto-s-triazine, 2-methyl-4,6-dimercapto-s-triazine, 2-ethylamino-4,6-dimercapto-
s-triazine, 2-diethylamino-4,6-dimercapto-s-triazine and the like. Among them,
2,4,6-trimercapto-s-triazine is preferred.

The quinoxalines are 2,3-dimercaptoquinoxaline compounds or quinoxaline-2,3-
It is a dithiocarbonate compound and may have a substituent of an alkyl group having 1 to 4 carbon atoms. Examples of the quinoxalines include 2,3-dimercaptoquinoxaline, quinoxaline-2,3-dithiocarbonate, 6-methylquinoxaline-2,3-dithiocarbonate, 6-isopropylquinoxaline-2,3-dithiocarbonate,
5,8-dimethylquinoxaline-2,3-dithiocarbonate and the like.

The amines are polyamine compounds having 2 to 20 carbon atoms, and specific examples thereof include hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, N, N'-dicinnamylidene-1,6-hexane. Diamine, hexamethylene diamine carbamate,
4,4'-methylenebis (cyclohexylamine) carbamate and the like.

The amount of the cross-linking agent used for the epihalohydrin rubber is the amount used for 100 parts by weight of the total of (A) and (B) (the same applies to the amount of the compounding agent used hereinafter, and is referred to as phr). The lower limit is 0.1 phr, preferably 0.2 phr, and the upper limit is 8 phr, preferably 5 phr.

As the crosslinking agent for the epihalohydrin rubber, an acid acceptor or a crosslinking accelerator can be used in combination. Examples of the acid acceptor include oxides, hydroxides, carbonates, carboxylates, silicates, borates, metaborates, and phosphites of metals belonging to Group II of the periodic table. Group metals include magnesium, calcium, barium, zinc and the like. Specific examples include, for example, magnesium oxide, magnesium hydroxide, barium hydroxide, magnesium carbonate,
Examples include barium carbonate, quicklime, slaked lime, calcium carbonate, calcium silicate, magnesium metaborate, calcium metaborate, barium metaborate, calcium stearate, zinc stearate, calcium phthalate, calcium phosphite, zinc oxide and the like.

Further, other acid acceptors include those in the Periodic Table I
Group VA metal oxides, basic carbonates, basic carboxylates, basic phosphites, basic sulfites, and tribasic sulfates are exemplified. Examples of the Group IVA metals in the periodic table include tin. No. Specific examples include tin stearate, tin oxide, and basic tin phosphite.

Further, other acid acceptors include those represented by the general formula Mg_X
Al_Y(OH)_{2X + 3Y-2}CO ₃・ WH₂O (however
X is a number from 1 to 10, Y is a number from 1 to 5, and w is a real number.
You. ).
A specific example is Mg_4.5Al₂(OH)₁₃CO
₃・ 3.5H₂O, Mg_4.5Al₂(OH)₁₃C
O_3, Mg₆Al₂(OH)₁₆CO₃・ 4H ₂O
And so on. The upper limit of the amount of the acid acceptor used is preferably 2
0 phr, more preferably 15 phr.

The crosslinking accelerator is an organic base having a dissociation constant PKa of 7 or more (supervised by Fujio Kotake, Large Organic Chemistry, Appendix 2 (Handbook of Organic Chemical Constants), pages 585-613 (Asakura Shoten)),
Salts of these organic bases capable of generating an organic base having a PKa of 7 or more, organic acid salts having a PKa of 7 or more, and the like are given.

Examples of the organic base include amines and guanidines of aliphatic hydrocarbons or aromatic hydrocarbons having 1 to 20 carbon atoms, and nitrogen-containing cyclic compounds having 3 to 20 carbon atoms. Guanidines may have a substituent such as an alkyl group having 1 to 10 carbon atoms and an aryl group.

Specific examples of the organic base include, but are not particularly limited to, benzylamine, dibenzylamine, guanidine, diphenylguanidine, diorthotolylguanidine, piperidine, pyrrolidine, 1,8-diaza-bicyclo (5,4,0 ) Undecene-7 (DBU), N-methylmorpholine and the like. Among them, diphenylguanidine and 1,8-diaza-bicyclo (5,4,0)
Undecene-7 is preferred. As the salt of the organic base, carbonate, phenol salt, hydrochloride, sulfate of the organic base,
Oxalates and the like can be mentioned.

Examples of the organic acid salts include sodium, potassium, zinc and piperidine salts of dithiocarbamic acids. Dithiocarbamic acids have 1 to 1 carbon atoms.
The compound is a dithiocarbamic acid compound substituted with an alkyl group, an aryl group, or the like consisting of 10, and specific examples include dimethyldithiocarbamic acid, diethyldithiocarbamic acid, dibutyldithiocarbamic acid, ethylphenyldithiocarbamic acid, and dibenzyldithiocarbamic acid. The upper limit of the amount of the crosslinking accelerator used is preferably 8
phr, more preferably 5 phr.

Crosslinking Agent for Nitrile Rubber Examples of the crosslinking agent for nitrile rubber include a sulfur crosslinking agent and an organic peroxide crosslinking agent. Among them, a sulfur-based cross-linking agent is preferable from the viewpoint of storage stability of the rubber composition, moldability and the like.

The sulfur-based crosslinking agent is not particularly limited, but includes sulfur and a sulfur-donating compound. Examples of the sulfur-donating compound include tetramethylthiuram disulfide, tetraethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, morpholine disulfide, and alkylphenol disulfide. Among them, sulfur is preferable.

The lower limit of the amount of the sulfur-based crosslinking agent used is 0.1 ph.
r, preferably 0.2 phr, with an upper limit of 10 phr, preferably 7 phr.

A crosslinking accelerator and a crosslinking assistant can be used in combination with the sulfur-based crosslinking agent. As a crosslinking accelerator, a crosslinking accelerator conventionally used in nitrile rubbers can be used. Preferred crosslinking accelerators include thiuram-based accelerators,
Thiazole accelerators, sulfenamide accelerators, and the like.

Examples of the thiuram-based accelerator include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram monosulfide, tetraethylthiuram disulfide and the like. Examples of the thiazole accelerator include 2-mercaptobenzothiazole and dibenzothiazyl disulfide.
Examples of the sulfenamide-based accelerator include N-cyclohexyl-2-benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide and the like. These crosslinking accelerators may be used in combination of two or more. The use amount of the crosslinking accelerator is preferably 12 phr or less, more preferably 10 phr or less.

Examples of the crosslinking aid include fatty acids, metal salts of fatty acids, and metal oxides. Fatty acids include stearic acid, oleic acid, lauric acid and the like. Examples of the fatty acid metal salts include zinc salts of the above fatty acids. The amount of the fatty acid and fatty acid metal salt used is preferably 5 phr or less, more preferably 3 phr or less. Examples of the metal oxide include zinc oxide and magnesium oxide. The amount of the metal oxide used is preferably 15 phr or less, more preferably 10 phr or less.

The organic peroxide-based crosslinking agent is not particularly limited, but may be dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide. , 2,5-dimethyl-2,5-di (t-
(Butylperoxy) -hexyne-3,1,1-di- (t
-Butylperoxy) -3,3,5-trimethylcyclohexane, 1,3-di (t-butylperoxyisopropyl) benzene, 5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylper Oxybenzoate and the like can be mentioned.

These organic peroxide crosslinking agents may be used in combination of two or more. The lower limit of the amount of the organic peroxide-based crosslinking agent used is 0.1 phr, preferably 0.1 phr.
2 phr, with an upper limit of 10 phr, preferably 5 phr
r.

As the organic peroxide-based crosslinking agent, a compound having at least two crosslinking unsaturated bonds in the molecule can be used as a crosslinking aid. Specific examples thereof include ethylene dimethacrylate, diallyl phthalate, N, N-m
-Phenylenedimaleimide, divinylbenzene, triallyl isocyanurate, trimethylolpropane trimethacrylate, liquid vinyl polybutadiene and the like. Two or more of these crosslinking aids can be used in combination. The upper limit of the amount of the crosslinking aid used together with the organic peroxide crosslinking agent is preferably 10 phr, more preferably 5 phr.

Other Compounds In addition to the above-mentioned components, a reinforcing filler, a filler, a plasticizer, an antioxidant, a crosslinking retarder, a processing aid, and the like may be added to the rubber composition for a hose of the present invention. it can. Examples of the reinforcing filler include carbon black and silica. Examples of the filler include calcium carbonate, clay, and talc. Examples of the plasticizer include di- (butoxy-ethoxyethyl) adipate, di- (2-ethylhexyl) adipate, and di- (2-ethylhexyl) phthalate. Examples of anti-aging agents include 2-mercaptobenzimidazole, 2,2,4-trimethyl-
Examples thereof include a polymer of 1,2-dihydroquinoline, nickel dibutyldithiocarbamate, and N-isopropyl-N′-phenyl-p-phenylenediamine. As a crosslinking retarder, N-cyclohexylthiophthalimide,
Examples include phthalic anhydride, benzoic acid, acetylsalicylic acid, and N-nitrosodiphenylamine. Processing aids include sorbitan monostearate and the like. These amounts are appropriately selected so as to satisfy various conditions required for processing conditions and crosslinked products.

The method for preparing the rubber composition for a hose of the present invention is not particularly limited. For example, an epihalohydrin rubber (A), a nitrile rubber (B), a cross-linking agent (C) and other compounding agents may be used. A method of mixing using a kneader such as a roll, a Banbury mixer, or an internal mixer is exemplified.

The order of mixing the respective components is not particularly limited, but a method in which the epihalohydrin-based rubber (A) and the nitrile-based rubber (B) are mixed in advance, and then the respective components are appropriately added and mixed. A method of appropriately adding various compounding components to the components, mixing the components, and then mixing the obtained rubber compositions is exemplified.

The rubber composition for hoses of the present invention preferably has an appropriate rubber hardness when crosslinked. The hardness (JIS A hardness) of the rubber at the time of crosslinking is preferably 40 ° or more, more preferably 50 ° or more, particularly preferably 60 ° or more, preferably 95 ° or less, more preferably 90 ° or less, particularly preferably 90 ° or less. Preferably it is 85 ° or less. If the hardness of the rubber is excessively low, problems such as poor connection between the hose and the fitting, and obstruction of fluid flow in the hose due to bending at the bent portion of the hose may occur. If the hardness of the rubber is excessively high, problems such as deterioration of the mounting property due to an increase in the rigidity of the hose may occur. The hardness of the rubber can be adjusted by appropriately selecting the type and amount of a crosslinking agent, a crosslinking aid, a reinforcing filler, a filler and a plasticizer used in the rubber composition.

Hose The hose according to the present invention may be composed entirely of a layer obtained by crosslinking the rubber composition for a hose, or at least one of the layers constituting the hose may be composed of the rubber composition for a hose. Are cross-linked. This crosslinked rubber layer
It is formed by forming the rubber composition into a hose shape and then crosslinking.

The method of forming the hose is not particularly limited. For example, a method of directly forming a hose using a single-screw or multi-screw extruder, an injection molding machine, an extrusion blow molding machine, and a transfer molding machine And a method of molding with a mold using a press molding machine or the like. As the molding conditions of the rubber composition, a molding temperature and a molding time are appropriately selected so that the constituent rubber composition does not deteriorate moldability due to a crosslinking reaction.

The crosslinking conditions of the rubber composition are selected appropriately in accordance with the crosslinking properties of the rubber composition, and an appropriate crosslinking temperature and crosslinking time are selected. Usually, a crosslinking temperature of about 100 to 250 ° C. and a time of about several minutes to 10 hours are used. Is the crosslinking time.

As a heating method for crosslinking the rubber composition, a method such as heating under pressure and high temperature steam, heating with high temperature air, high temperature co-melting salt and high frequency heating can be used. Also, a method of heating a rubber composition by heating a mold by electric heating or the like, or a method of heating a rubber composition by using self-shearing heat generated when the rubber composition passes through an injection nozzle in an injection molding machine. Etc. can be adopted. Usually, a method in which a hose-shaped molded product is inserted into a pressure-resistant can and heated by pressurized high-temperature steam is adopted.

The hose of the present invention may have a crosslinked rubber layer made of another rubber composition or a layer made of an oil-resistant resin in order to satisfy various performances required for the hose. Other rubbers constituting the rubber composition include nitrile rubber, hydrogenated nitrile rubber, epihalohydrin rubber, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, acrylic rubber, fluorine rubber and the like. Other rubber compositions are prepared by appropriately selecting a crosslinking agent, a crosslinking aid, and other compounds that are optimal for each rubber constituting the rubber composition.

Examples of the oil-resistant resin include fluorine resin, fluorine-based thermoplastic elastomer, nylon resin, polyamide-based thermoplastic elastomer, polyester resin, polyester-based thermoplastic elastomer, and polyurethane-based thermoplastic elastomer.

The hose of the present invention may have a reinforcing layer composed of natural fibers, chemical fibers, metal wires, etc. in order to improve the pressure resistance. Natural fibers include cotton and hemp. Examples of the chemical fiber include rayon, vinylon, nylon, polyester, and polypropylene. Examples of the metal wire include a stainless steel wire and a steel wire.

When the hose of the present invention has a multilayer structure and has a layer interface composed of different kinds of components, an adhesive may be applied between the layers to improve the bonding force between the layers, or an adhesion improving aid may be used. Can be added to the rubber composition.

In order to form a hose having a multilayer structure, the same molding method can be used a plurality of times, or a molding method combining various molding methods can be adopted. For example, after forming the innermost layer of a cylindrical rubber composition on the outer peripheral portion of the mandrel with the first extruder, forming a reinforcing layer made of polyester fiber on the outer peripheral surface of the rubber composition, and further forming the rubber layer on the second extruder. There is a method of forming a multi-layer hose by coating the outermost layer of the composition.

The hose of the present invention having a crosslinked rubber layer excellent in fuel oil permeability and ozone resistance is characterized in that a fuel liquid such as gasoline, kerosene, light oil or fuel vapor permeates through the hose layer and is exposed to the atmosphere. It is characterized in that it can suppress the amount of radiation to the air and can withstand ozone in the air for a long time.

The hose of the present invention can be used as a hose for fuel oil, fuel gas, lubricating oil, air and the like. In particular, it is suitable for hoses used as automobile parts, which require long-term ozone resistance.

The hoses used as automobile parts include fuel system, brake system, power steering system, control system, air conditioner system, intake system, oil cooling system, clutch system,
There are various hoses used for parts such as suspension systems.

Specifically, for example, a fuel hose or a fuel inlet hose is used in a fuel system, a hydraulic brake hose or a vacuum brake hose is used in a brake system, and a high-pressure power steering hose or a suction hose is used in a power steering system. The control system includes a ventilation hose and a vacuum sensing hose. The hose of the present invention is particularly suitable as a fuel hose or a fuel inlet hose that requires excellent fuel permeation resistance among the above-mentioned hoses.

[0075]

The present invention will be specifically described below with reference to examples and comparative examples. (Production of Epihalohydrin Rubbers A1 to A6) As monomers, epichlorohydrin (abbreviated as ECH), allyl glycidyl ether (abbreviated as AGE) and ethylene oxide (abbreviated as EO) are used, and toluene is used. Was used as a polymerization solvent, and a polymerization solution was obtained by solution polymerization using an organoaluminum-phosphate compound-based polymerization catalyst described in JP-A-56-4628. After removing the solvent from the polymerization solution by a steam stripping method, the polymer separated by filtration was vacuum dried to obtain a rubbery polymer. For the epihalohydrin rubbers A1 to A6 obtained by varying the monomer composition, the content of each monomer unit in each polymer was measured by ¹³ C-NMR analysis. In addition, Mooney viscosity (ML _{1 + 4} ,
100 ° C) was measured according to JIS K6300.
The monomer unit content and Mooney viscosity in the polymer of the epichlorohydrin rubbers A1 to A6 are shown below.

Epihalohydrin rubber A1 (ECH unit: 84 mol%, AGE unit: 16 mol%, ML
_{1 + 4} , 100 ° C .: 50) Epihalohydrin rubber A2 (ECH unit: 61 mol%, AGE unit: 14 mol%, EO unit: 25 mol%, ML _{1 + 4} , 100 ° C .: 70) Epihalohydrin rubber A3 (ECH unit: 90) Mol%, AGE unit: 10 mol%, ML _{1 +} 4,100
C: 53) Epihalohydrin rubber A4 (ECH unit: 94 mol%, AGE unit: 6 mol%, ML _{1 + 4} , 100 ° C:
55) Epihalohydrin-based rubber A5 (ECH unit: 77 mol%, AGE unit: 23 mol%, ML _{1 + 4} , 100 ° C.)
52) Epihalohydrin rubber A6 (ECH unit: 30 mol%, AGE unit: 16 mol%, EO unit: 54 mol%,
ML _{1 + 4} , 100 ° C: 76)

(Example 1) [Preparation of rubber composition] Epihalohydrin rubber A1
0 parts by weight, 60 parts by weight of nitrile rubber B1, 40 parts by weight of FEF carbon black, 1.0 part by weight of stearic acid, 5 parts by weight of a plasticizer (di- (butoxyethoxyethyl) adipate), zinc oxide (zinc white powder 1) No.) 5 parts by weight, acid acceptor (magnesium oxide) 1.0 part by weight and crosslinking retarder
1.0 part by weight of (N- (cyclohexylthio) phthalimide) was kneaded using a Banbury mixer. 1.0 part by weight of a crosslinking agent C1 (sulfur) of the obtained kneaded product and nitrile rubber, 1.5 parts by weight of a crosslinking accelerator (N-cyclohexyl-2-benzothiazylsulfenamide), and epichlorohydrin Phosphorus rubber crosslinker C2 (ethylenethiourea)
2.0 parts by weight were mixed with an open roll to prepare a rubber composition.

[Preparation of Crosslinked Rubber Sheet and Tensile Test] The obtained rubber composition was crosslinked using a hot plate press at 160 ° C. for 45 minutes to obtain a crosslinked rubber sheet having a thickness of 2 mm. Regarding crosslinked rubber sheet, JISK630
According to one test method, tensile strength, elongation at break, and hardness were measured. Table 1 shows the results.

[Dynamic ozone resistance test of crosslinked rubber sheet]
According to JIS K6301, the test piece was exposed to an atmosphere with an ozone concentration of 50 pphm and a temperature of 40 ° C. under repeated elongation of 0 to 40%, and the crack generation state of the test piece was observed with the lapse of time. Table 1 shows the results. NC shown in Table 1 indicates a state without crack generation, and A2, B3, etc. indicate crack states described in the above JIS. The longer the time until crack generation, the better the ozone resistance.

[Test of Fuel Oil Permeation Resistance of Crosslinked Rubber Sheet]
Test fuel oil C in an aluminum cup with an empty volume of 100 ml
(Isooctane / toluene = 50/50 volume ratio) 50 m
and a crosslinked rubber sheet cut into a disk having a diameter of 61 mm was fixed to the open end of the cup with a fastener. This was left in a 40 ° C. thermostat with a cup so that the crosslinked rubber sheet side was down. Every 24 hours, the weight of the entire cup was measured, and the measurement was continued until the fuel oil loss per unit time became constant. The fuel oil permeation amount was determined from the area of the crosslinked rubber sheet to which the test fuel oil was in contact, the thickness of the crosslinked rubber sheet, and the unit time. Table 1 shows the permeation amount of the fuel oil measured with the crosslinked rubber sheet. The smaller the fuel oil permeation amount, the more excellent the fuel oil permeation resistance.

[Manufacture of Hose] Using a single screw extruder, the rubber composition was formed into a tube having an inner diameter of 10 mm and a wall thickness of 2.0 mm. A metal mandrel having an outer diameter of 10 mm was inserted into the tubular molded product, placed in a pressure-resistant can, and crosslinked by heating with pressurized steam at a temperature of 160 ° C for 45 minutes. Thereafter, the metal mandrel was pulled out to obtain a cylindrical hose having a single-layer structure.

[Ozone Resistance Test of Hose] A hose cut to a length of 200 mm was wound around a mandrel having an outer diameter of 70 mm and fixed. This is converted to an ozone concentration of 100 pph
The hose was exposed to an atmosphere of m and 40 ° C., and the occurrence of cracks in the hose was observed over time. Table 1 shows the results. The notation in Table 1 is the same as in the dynamic ozone resistance test of the crosslinked rubber sheet.

[Test of Fuel Oil Permeation Resistance of Hose] 200 m
One end of the hose cut to a length of 10 m
m, a 20 mm long metal rod was inserted and sealed with Teflon tape. From the other open end, test fuel oil C12ml
Was injected into a hose and sealed in the same manner. After measuring the weight of the whole hose (referred to as W1), the hose was left in a thermostat at 40 ° C. for 48 hours. After the standing, the weight of the whole hose taken out was measured (referred to as W2), and the weight change amount (W2) was measured.
W1-W2) was used to determine the fuel oil permeation amount. Table 1 shows the results. The smaller the fuel oil permeation amount, the better the fuel oil permeation resistance.

(Examples 2 to 4, Comparative Examples 1 to 5) An experiment was conducted in the same manner as in Example 1 except for the formulations shown in Table 1. Table 1 shows the results.

Comparative Example 1 used epichlorohydrin rubber A4 in which the unsaturated epoxide monomer unit content of the epichlorohydrin rubber was less than the lower limit of the range of the present invention. Poor ozone resistance. Comparative Example 2 used an epichlorohydrin-based rubber A5 in which the unsaturated epoxide monomer unit content of the epichlorohydrin-based rubber was larger than the upper limit of the range of the present invention. Poor permeability and remarkably poor ozone resistance. Comparative Example 3 shows that epichlorohydrin-based rubber has an epihalohydrin monomer unit content of less than the lower limit of the range of the present invention and other monomer unit content of the epichlorohydrin-based rubber is larger than the upper limit of the range of the present invention. Since A6 was used, the fuel oil permeability was inferior and the ozone resistance was significantly inferior to Example 1. In Comparative Example 4, the ratio of the epichlorohydrin rubber was lower than the lower limit of the range of the present invention, so that the ozone resistance was significantly inferior to Example 1.
In Comparative Example 5, the ratio of the epichlorohydrin-based rubber was larger than the upper limit of the range of the present invention, so that the ozone resistance was significantly inferior to Example 1.

On the other hand, the rubber compositions for hoses of the present invention of Examples 1 to 4 and the hoses having a layer formed by crosslinking the hoses are excellent in fuel oil permeability and ozone resistance.

[0087]

[Table 1]

(Note) (1) Nipol DN101L manufactured by Zeon Corporation
(Acrylonitrile content: 42.5% by weight, M
L _{1 + 4} , 100 ° C .: 60) (2) Nipol DN200 manufactured by Zeon Corporation
(Acrylonitrile content: 33.5% by weight, M
L _{1 + 4} , 100 ° C .: 43) (3) N-cyclohexyl-2-benzothiazylsulfenamide (4) ethylenethiourea (5) 2,4,6-trimercapto-s-triazine

[0089]

According to the present invention, there is provided a rubber composition for hoses having excellent fuel oil permeability and ozone resistance, and a hose having a layer obtained by crosslinking the rubber composition. The hose of the present invention is suitable as a fuel oil hose.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 AC07X CH04W DA046 EN036 EN046 EN116 EU146 EU186 EV076 EV086 EV126 EV166 EV346 FD146 FD200 GN00

Claims (2)

[Claims] 1. An epihalohydrin monomer unit of 40 to 92.
Cross-linking of epihalohydrin-based rubber (A), nitrile-based rubber (B), and epihalohydrin-based rubber composed of 8% to 20% by mole of unsaturated epoxide monomer unit and 0 to 40% by mole of other monomer unit A rubber composition containing at least one crosslinking agent (C) selected from a crosslinking agent and a nitrile rubber crosslinking agent, wherein the ratio of (A) to the total amount of (A) and (B) is 20 to 70. A rubber composition for a hose, which is a percentage by weight. 2. A hose having a layer obtained by crosslinking the rubber composition for a hose according to claim 1.