JP2008201903A - Acrylic rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic rubber composition with processability improved by suppressing tackiness to a metallic material without detriment to mechanical properties and permanent compression set and to provide a vulcanizate thereof. <P>SOLUTION: The acrylic rubber composition is obtained by compounding (A) an acrylic rubber with (B) at least one compound selected from a metal alkylsulfonate and a metal alkylsulfate, (C) a metal stearate, and (D) a vulcanizer. The vulcanizate is obtained by vulcanizing the acrylic rubber composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an acrylic rubber composition. More specifically, the present invention relates to an acrylic rubber composition excellent in mechanical properties and compression set and having good processability, and a vulcanized product thereof.

  Acrylic rubber and its vulcanizates are excellent in physical properties such as heat resistance, oil resistance, mechanical properties and compression set properties, and are widely used as materials for hose members, seal members, and vibration-proof rubber members in automobile engine rooms. Has been.

  With respect to these members, the use environment has been increased in heat, and acrylic rubber having performances such as heat resistance and oil resistance, which are more excellent than ever, has been desired. In addition, acrylic rubber having a high vulcanization rate is demanded for the purpose of improving the productivity of the above members.

  In order to meet these demands, a rubber composition with excellent heat resistance, oil resistance, weather resistance, etc. and a good balance of physical properties, monoepoxy such as ethylene, vinyl acetate, acrylate ester and glycidyl methacrylate as a crosslinking point monomer A rubber composition comprising a copolymer comprising a monoolefin compound and a vulcanizing agent has been developed (see Patent Document 1).

  In addition, acrylic rubber with a carboxyl group as a crosslinking point is used as an acrylic rubber composition that has good vulcanization speed and scorch stability without impairing heat resistance, oil resistance, mechanical properties and compression set properties. (See Patent Document 2).

Japanese Patent Publication No.59-14498 JP 2002-317091 A

  The rubber composition disclosed in Patent Document 1 has a good balance of physical properties such as heat resistance, oil resistance, and weather resistance, but roll adhesion during kneading and mold adhesion during molding may be severe. There is a demand for improved adhesion to metal materials.

  The acrylic rubber composition disclosed in Patent Document 2 is also a material having a balance of vulcanization speed, mechanical characteristics, compression set characteristics, heat resistance, heat resistance, etc., but particularly roll adhesion during kneading. In some cases, mold adhesion at the time of molding is severe, and there is a demand for improved adhesion to metal materials.

  Accordingly, the main object of the present invention is to provide an acrylic rubber composition and a vulcanized product thereof that have improved workability by suppressing adhesion to a metal material without impairing mechanical properties and compression set. To do.

  In order to solve the above problems, the present invention provides (A) an acrylic rubber, (B) at least one compound selected from an alkylsulfonic acid metal salt and an alkylsulfuric acid metal salt, (C) a stearic acid metal salt, and (D And) a vulcanizing agent.

  (A) The acrylic rubber is preferably a carboxyl group-containing acrylic rubber. Further, 0.1 to 5% by mass of ethylene monomer units, 1 to 12% by mass of maleic acid monoalkyl ester units, and 98.9 to 83% by mass of acrylic acid alkyl ester and / or acrylic acid alkoxyalkyl ester units. An acrylic rubber blended with is more preferred.

  (B) It is desirable to use sodium alkyl sulfonate for the alkyl sulfonate metal salt and sodium alkyl sulfate for the alkyl sulfate metal salt. Moreover, (C) at least 1 type chosen from a magnesium stearate and a zinc stearate can be employ | adopted suitably for a stearic acid metal salt.

  (B) The compounding quantity of the at least 1 type compound chosen from the alkylsulfonic acid metal salt and the alkylsulfuric acid metal salt shall be 1-4 mass parts with respect to 100 mass parts of acrylic rubbers, (C) The compounding quantity of a stearic acid metal salt Is preferably 0.1 to 4 parts by mass with respect to 100 parts by mass of the acrylic rubber.

  (D) As a vulcanizing agent, a guanidine compound and a diamine compound are suitable, and hexamethylenediamine carbamate is particularly preferred for the diamine compound.

  The acrylic rubber composition can be blended with at least one monoamine compound selected from primary amine, secondary amine, tertiary amine, and primary amine acetate.

  The present invention also provides a vulcanizate obtained by vulcanizing an acrylic rubber composition.

  According to the present invention, it is possible to obtain an acrylic rubber composition having improved workability by suppressing adhesion to a metal material without impairing mechanical properties and compression set.

  The acrylic rubber composition according to the present invention comprises (A) an acrylic rubber, (B) at least one compound selected from an alkylsulfonic acid metal salt and an alkylsulfuric acid metal salt, (C) a stearic acid metal salt, and (D ) Vulcanizing agent.

  (A) Acrylic rubber is mainly composed of unsaturated monomers such as alkyl acrylates and alkoxyalkyl acrylates, containing carboxyl groups, or cross-linking monomers containing epoxy groups, active chlorine groups, etc. Acrylic rubber characterized in that

  First, unsaturated monomers that can be used in the present invention will be described. The following unsaturated monomers may be used alone or in combination of two or more.

  Although it does not specifically limit as acrylic acid alkyl ester, For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-octyl acrylate 2-ethylhexyl acrylate, n-decyl acrylate, n-dodecyl acrylate, n-octadecyl acrylate.

  Although it does not specifically limit as acrylic acid alkoxyalkyl ester, For example, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2- (n-propoxy) ethyl acrylate, 2- (n-butoxy) ethyl acrylate, There are 3-methoxypropyl acrylate, 3-ethoxypropyl acrylate, 2- (n-propoxy) propyl acrylate, 2- (n-butoxy) propyl acrylate.

  In addition, acrylates copolymerizable with these include cyanomethyl acrylate, 1-cyanoethyl acrylate, 2-cyanoethyl acrylate, 1-cyanopropyl acrylate, 2-cyanopropyl acrylate, 3-cyanopropyl acrylate, 4-cyanobutyl. Examples include acrylate, 6-cyanohexyl acrylate, 2-ethyl-6-cyanohexyl acrylate, and 8-cyanooctyl acrylate.

  Further, 1,1-dihydroperfluoroethyl (meth) acrylate, 1,1-dihydroperfluoropropyl (meth) acrylate, 1,1,5-trihydroperfluorohexyl (meth) acrylate, 1,1,2,2-tetrahydro Fluorine-containing compounds such as perfluoropropyl (meth) acrylate, 1,1,7-trihydroperfluoroheptyl (meth) acrylate, 1,1-dihydroperfluorooctyl (meth) acrylate, 1,1-dihydroperfluorodecyl (meth) acrylate ( Hydroxyl group-containing (meth) acrylic acid ester such as (meth) acrylic acid ester, 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, diethylaminoethyl (meta) Acrylates, tertiary amino group-containing, such as dibutyl aminoethyl (meth) acrylate (meth) acrylic acid ester, and the like may be used methacrylic acid esters such as methyl acrylate, octyl methacrylate.

  Next, the crosslinking point monomer that can be used in the present invention will be described. The following crosslinking point monomers may be used alone or in combination of two or more. In this case, the blending ratio of the crosslinking point monomer is preferably 1 to 12% by mass, and more preferably 1.5 to 5% by mass in all monomers.

  Examples of the crosslinking point monomer containing a carboxyl group include, but are not limited to, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and aliphatic unsaturated compounds such as maleic acid, fumaric acid, itaconic acid, and citraconic acid. Dicarboxylic acid or monomethylmalate, monoethylmalate, mono-n-propylmalate, monoisopyrmalate, mono-n-butylmalate, monoisobutylmalate, monomethylfumarate, monoethylfumarate, mono-n- Propyl fumarate, monoisopropyl malate, mono-n-butyl fumarate, monomethyl itaconate, monoethyl itaconate, mono-n-propyl itaconate, mono-n-propyl citraconic acid, mono-n-butyl citraconic acid Ate, monoisobutylcitraconate, etc. At least one monomer selected from the group consisting of dicarboxylic acid monoester can be used.

  Although it does not specifically limit as a crosslinking point monomer containing an epoxy group, For example, at least 1 type chosen from the group of epoxy group containing unsaturated compounds, such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methallyl glycidyl ether. The monomer can be used.

  Although it does not specifically limit as a crosslinking point monomer containing an active chlorine group, For example, active chlorine groups, such as 2-chloroethyl vinyl ether, 2-chloroethyl acrylate, vinyl benzyl chloride, vinyl chloroacetate, allyl chloroacetate At least one monomer selected from the group of contained unsaturated compounds can be used.

  In the above cross-linking point monomer, the cross-linking point monomer containing a carboxyl group has good vulcanization rate and scorch stability without impairing heat resistance, oil resistance, mechanical properties and compression set properties to the acrylic rubber composition. Can be particularly preferably employed.

  The acrylic rubber may be copolymerized with other monomers copolymerizable with the above-mentioned monomers within the range not impairing the object of the present invention. Examples of other copolymerizable monomers include, but are not limited to, alkyl vinyl ketones such as methyl vinyl ketone, vinyl and allyl ethers such as vinyl ethyl ether and allyl methyl ether, styrene, and α-methyl styrene. , Vinyl aromatic compounds such as chlorostyrene, vinyl toluene, vinyl naphthalene, vinyl nitriles such as acrylonitrile, methacrylonitrile, acrylamide, propylene, butadiene, isoprene, pentadiene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, There are ethylenically unsaturated compounds such as ethylene, vinyl acetate and vinyl propionate.

  In particular, when ethylene is copolymerized with acrylic rubber, the proportion is preferably 0.1 to 5% by mass in all monomers. In this case, the ratio of the crosslinking point monomer is 1 to 12% by mass, preferably 1.5 to 5% by mass, and the ratio of the unsaturated monomer such as alkyl acrylate is 83 to 98.9% by mass, preferably 90 to 90%. It is good to set to the range of 98.4 mass%. By setting in these ranges, an acrylic rubber can be obtained in which the balance between cold resistance and oil resistance and the balance between elongation and tensile strength are remarkably improved.

  The acrylic rubber can be obtained by copolymerizing these monomers by a known method such as emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization and the like.

  The (A) acrylic rubber obtained as described above, (B) at least one compound selected from an alkylsulfonic acid metal salt and an alkylsulfuric acid metal salt, (C) a stearic acid metal salt, and (D) a vulcanization By blending with an agent, an acrylic rubber composition having improved workability by suppressing adhesion to a metal material can be obtained without impairing mechanical properties, compression set, and heat resistance.

  (B) Alkyl sulfonic acid metal salts include sodium alkyl sulfonate, potassium alkyl sulfonate, calcium alkyl sulfonate and the like. From the balance between the effect of suppressing adhesion to metal materials and the mechanical properties and compression set properties, alkyl Sodium sulfonate is preferred.

  Sodium alkyl sulfonates include sodium butyl sulfonate, sodium pentyl sulfonate, sodium hexyl sulfonate, sodium heptyl sulfonate, sodium octyl sulfonate, sodium nonyl sulfonate, sodium decyl sulfonate, sodium undecyl sulfonate, dodecyl sulfone. Acid sodium, sodium tridecyl sulfonate, sodium tetradecyl sulfonate, sodium pentadecyl sulfonate, sodium hexadecyl sulfonate, sodium heptadecyl sulfonate, sodium octadecyl sulfonate, sodium nonadecyl sulfonate, sodium eicosyl sulfonate, etc. And at least one selected from these groups can be used.

  Although there is no restriction | limiting in particular in carbon number of sodium alkylsulfonate, C4-C25 is preferable.

  (C) Alkyl sulfate metal salts include sodium alkyl sulfate, potassium alkyl sulfate, calcium alkyl sulfate and the like, and sodium alkyl sulfate is preferred from the balance of adhesion suppression effect to metal material and mechanical properties and compression set properties. .

  Examples of sodium alkyl sulfate include sodium butyl sulfate, sodium pentyl sulfate, sodium hexyl sulfate, sodium heptyl sulfate, sodium octyl sulfate, sodium nonyl sulfate, sodium decyl sulfate, sodium undecyl sulfate, sodium dodecyl sulfate, sodium tridecyl sulfate, sodium tetradecyl sulfate, There are sodium pentadecyl sulfate, sodium hexadecyl sulfate, sodium heptadecyl sulfate, sodium octadecyl sulfate, sodium nonadecyl sulfate, sodium eicosyl sulfate, and at least one selected from these groups can be used.

  Although there is no restriction | limiting in particular in carbon number of sodium alkyl sulfate, C4-C25 is preferable.

  Examples of (C) metal stearate include sodium stearate, magnesium stearate, aluminum stearate, potassium stearate, calcium stearate, manganese stearate, copper stearate, and zinc stearate, and are selected from these groups. At least one type can be used.

  The metal species of the metal stearate is not particularly limited, but magnesium stearate and zinc stearate are preferably used.

  (B) The addition amount of at least one compound selected from alkylsulfonic acid metal salts and alkylsulfuric acid metal salts is 1 to 4 parts by mass with respect to 100 parts by mass of acrylic rubber, and (C) the addition amount of stearic acid metal salt is Moreover, 0.1-4 mass parts is suitable with respect to 100 mass parts of acrylic rubber. When the addition amount of (B) and (C) is less than the above-mentioned mass part range, the improvement of the adhesiveness with the metal material is insufficient, and if exceeding the same range, the compression set is undesirably deteriorated.

  When the acrylic rubber is a carboxyl group-containing acrylic rubber, (D) a carboxyl group-containing acrylic rubber composition excellent in mechanical properties, compression set, and heat resistance by using a guanidine compound and a diamine compound as a vulcanizing agent. Is obtained.

  Examples of guanidine compounds include, but are not limited to, guanidine, tetramethylguanidine, dibutylguanidine, diphenylguanidine, di-o-tolylguanidine, and the like. Di-o-tolylguanidine is preferably used from the balance of mechanical properties and compression set properties.

  The addition amount of the guanidine compound is preferably 0.1 to 10 parts by mass, and 0.5 to 5 parts by mass with respect to 100 parts by mass of the carboxyl group-containing acrylic rubber from the viewpoint of performing a necessary and sufficient vulcanization reaction. The range of is more preferable.

  Although it does not specifically limit as a diamine compound, For example, aliphatic diamine, such as hexamethylene diamine, hexamethylene diamine carbamate, triethylenetetramine, tetraethylenepentamine, 4,4'- diamino dicyclohexyl methane, 3,3 ' -Dihydrazides such as dimethyl 4,4'-diaminodicyclohexylmethane, 1,3-bis (aminomethyl) cyclohexane, adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, 4,4'-methylenedi Aniline, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, o-toluylenediamine, m-toluylenediamine, o-xylylenediamine, m-xylylenediamine, p-xylylenediamine 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-diaminodiphenyl sulfide, 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane, 1,3-bis (4- Aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) pentane, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-diaminodiphenyl sulfone, bis (4-3-aminophenoxy) phenyl sulfone, 2,2′-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzanilide, bis [4- (4-aminophenoxy There are aromatic diamines such as phenyl] sulfone, bis (4-4-aminophenoxy) phenyl sulfone, bis (4-3-aminophenoxy) phenyl sulfone, 9,9-bis (4-aminophenyl) fluorene, and vulcanization From the balance of speed, mechanical properties, and compression set properties, hexamethylene diamine carbamate is preferably used.

  The addition amount of the vulcanizing agent is not particularly limited, but is preferably 0.01 to 4 parts by mass with respect to 100 parts by mass of the acrylic rubber from the viewpoint that a good vulcanization reaction is obtained, and 0.05 to The range of 3 parts by mass is more preferable.

  The acrylic rubber composition can be blended with at least one monoamine compound selected from primary amine, secondary amine, tertiary amine, and primary amine acetate.

  Although it does not specifically limit as primary amine, For example, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tetra Decylamine, hexadodecylamine, stearylamine, octadecylamine, eicosylamine, methanolamine, ethanolamine, aniline, cyclohexylamine, benzylamine, 2-aminotoluene, 3-aminotoluene, 4-aminotoluene, 2,4- Dimethylaniline, 2,3-dimethylaniline, 2,5-dimethylaniline, 2,6-dimethylaniline, 3,4-dimethylaniline, 3,5-dimethylaniline, 2,4,5-trimethylaniline 2,4,6-trimethylaniline, 3,4,5,6-tetramethylaniline, 2,4,5,6-tetramethylaniline, 2,3,5,6-tetramethylaniline, 2-ethyl- 3-hexylaniline, 2-ethyl-4-hexylaniline, 2-ethyl-5-hexylaniline, 2-ethyl-6-hexylaniline, 3-ethyl-4-hexylaniline, 3-ethyl-5-hexylaniline, 3-ethyl-2-hexylaniline, 4-ethyl-2-hexylaniline, 5-ethyl-2-hexylaniline, 4-ethyl-3-hexylaniline, 6-ethyl-2-hexylaniline, 5-ethyl-3 -Hexylaniline, 3,4,6-triethylaniline, 2-methoxyaniline, 3-methoxyaniline, 4-methoxyaniline, 2-methoxy -3-methylaniline, 2-methoxy-4-methylaniline, 2-methoxy-5-methylaniline, 2-methoxy-6-methylaniline, 3-methoxy-2-methylaniline, 3-methoxy-4-methylaniline 3-methoxy-5-methylaniline, 3-methoxy-6-methylaniline, 4-methoxy-2-methylaniline, 4-methoxy-3-methylaniline, 2-ethoxyaniline, 3-ethoxyaniline, 4-ethoxy Aniline, 4-methoxy-5-methylaniline, 4-methoxy-6-methylaniline, 2-methoxy-3-ethylaniline, 2-methoxy-4-ethylaniline, 2-methoxy-5-ethylaniline, 2-methoxy -6-ethylaniline, 3-methoxy-2-ethylaniline, 3-methoxy-4-ethylaniline, 3-methoxy-5-ethylaniline, 3-methoxy-6-ethylaniline, 4-methoxy-2-ethylaniline, 4-methoxy-3-ethylaniline, 2-methoxy-2,3,4-trimethylaniline, 3 There are -methoxy-2,4,5-trimethylaniline, 4-methoxy-2,3,5-trimethylaniline, bis (2-cyanoethyl) amine and the like, and at least one selected from these groups can be used.

  The addition amount of these primary amines is not particularly limited, but is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of acrylic rubber from the viewpoint of improving processability and vulcanized properties. A range of 0.05 to 2 parts by mass is more preferable.

  It is preferable to use not only primary amines but also monoamine compounds such as secondary amines, tertiary amines, and amine acetates in the acrylic rubber composition because the processability during kneading is improved.

  The secondary amine is not particularly limited, and examples thereof include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, diene. Examples include dodecylamine, ditetradecylamine, dihexadecylamine, dimethanolamine, diethanolamine, diphenylamine, dicyclohexylamine, nitrosodimethylamine, and nitrosodiphenylamine.

  The tertiary amine is not particularly limited. For example, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecyl. Amine, triundecylamine, tridodecylamine, tritetradecylamine, trihexadecylamine, tristearylamine, trioctadecylamine, trieicosylamine, trimethanolamine, triethanolamine, triphenylamine, trocyclohexylamine, etc. is there.

  Although it does not specifically limit as primary amine acetate, For example, methylamine acetate, ethylamine acetate, propylamine acetate, butylamine acetate, pentylamine acetate, hexylamine acetate, heptylamine acetate , Octylamine acetate, nonylamine acetate, decylamine acetate, undecylamine acetate, dodecylamine acetate, tetradecylamine acetate, hexadecylamine acetate, stearylamine acetate, octadecylamine acetate, methanolamine acetic acid There is salt.

  The addition amount of these secondary amines, tertiary amines, and primary amine acetates is not particularly limited, but from the viewpoint of improving processability and vulcanizate properties, it is based on 100 parts by mass of acrylic rubber. 0.01 to 10 parts by mass is preferable, and a range of 0.05 to 2 parts by mass is more preferable.

  The acrylic rubber composition is obtained by kneading these compounds at a temperature not higher than the vulcanization temperature. The obtained acrylic rubber composition can be molded into various desired shapes and then vulcanized to obtain a vulcanized product, or can be molded into various shapes after vulcanization. The vulcanization temperature can be appropriately set depending on the composition of the acrylic rubber composition and the type of the vulcanizing agent, and is usually in the range of 130 to 200 ° C.

As the apparatus for kneading, molding and vulcanizing these acrylic rubber compositions and the apparatus for kneading and molding the vulcanized products of acrylic rubber compositions, those usually used in the rubber industry can be used.

  Acrylic rubber compositions can be molded and vulcanized by adding fillers, reinforcing agents, plasticizers, lubricants, anti-aging agents, stabilizers, silane coupling agents, etc., depending on the purpose when they are put to practical use. it can.

  As fillers and reinforcing agents, fillers and reinforcing agents used in normal rubber applications can be added. For example, fillers and reinforcing agents such as carbon black, silica, clay, talc and calcium carbonate are used. is there. The total amount of these additives is preferably in the range of 30 to 100 parts by mass with respect to 100 parts by mass of the acrylic rubber composition.

  As the plasticizer, plasticizers used for ordinary rubber applications can be added, and examples thereof include ester plasticizers, polyoxyethylene ether plasticizers, and trimellitate plasticizers. The addition amount of the plasticizer is preferably in the range of up to about 50 parts by mass with respect to 100 parts by mass of the acrylic rubber composition.

  The acrylic rubber composition and the vulcanized product thereof are particularly suitably used as seal parts such as rubber hoses, gaskets and packing, and vibration-proof rubber parts.

Examples of rubber hoses include transmission oil cooler hoses, engine oil cooler hoses, air duct hoses, turbo intercooler hoses, hot air hoses, radiator hoses, power steering hoses, fuel system hoses, drain systems for automobiles, construction machinery, hydraulic equipment, etc. There are hoses for use.

  As a structure of the rubber hose, not only a single-layer hose obtained from the acrylic rubber composition and the vulcanized product thereof, but also a layer made of the acrylic rubber composition and the vulcanized product, for example, fluorine rubber, fluorine-modified acrylic rubber, A multi-layer hose in which hydrin rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene-propylene rubber, silicone rubber, chlorosulfonated polyethylene rubber and the like are combined as an inner layer, an intermediate layer, or an outer layer may be used. Further, as is generally done, reinforcing yarns or wires may be provided in the middle of the hose or in the outermost layer of the rubber hose.

  Seal parts include, for example, engine head cover gasket, oil pan gasket, oil seal, lip seal packing, O-ring, transmission seal gasket, crankshaft, camshaft seal gasket, valve stem, power steering seal belt cover seal, constant speed There are joint boot materials and rack and pinion boot materials.

  Anti-vibration rubber parts include, for example, a damper pulley, a center support cushion, and a suspension bush.

Production of acrylic rubber A _{1 In} a pressure resistant reaction vessel with an internal volume of 40 liters, 17 kg of an aqueous solution of 7.8 kg of ethyl acrylate, 3.4 kg of n-butyl acrylate, 0.5 kg of monobutyl maleate, 4% by weight of partially saponified polyvinyl alcohol Then, 22 g of sodium acetate was added and mixed well in advance with a stirrer to prepare a uniform suspension. After replacing the air in the upper part of the tank with nitrogen, ethylene was injected into the upper part of the tank, and the pressure was adjusted to 20 kg / cm ² . Stirring was continued and the inside of the tank was maintained at 55 ° C., and then an aqueous t-butyl hydroperoxide solution was injected from a separate inlet to initiate polymerization. During the reaction, the temperature in the tank was maintained at 55 ° C., and the reaction was completed in 6 hours. The resulting polymerization solution was added sodium borate solution to solidify the polymer, to obtain an acrylic rubber A ₁ performing dewatering and drying. This acrylic rubber A ₁ is composed of 2.2% by mass of ethylene monomer units, 2.2% by mass of monobutyl maleate monomer units, 69.3% by mass of ethyl acrylate monomer units, n-acrylic acid n -It was a copolymer composition of 26.3 mass% of butyl monomer units. The monobutyl maleate monomer unit was quantified by dissolving the raw rubber of the copolymer in toluene and performing neutralization titration with potassium hydroxide. For other monomer unit components, a nuclear magnetic resonance spectrum was collected and each component was quantified.

Production of acrylic rubber A _{2 In} a pressure resistant reaction vessel with an internal volume of 40 liters, ethyl acrylate 7.8 kg, acrylic acid-2-methoxyethyl 3.4 kg, maleic acid monobutyl 0.5 kg, partially saponified polyvinyl alcohol 4% by mass 17 kg of an aqueous solution and 22 g of sodium acetate were added and mixed well in advance with a stirrer to prepare a uniform suspension. After replacing the air in the upper part of the tank with nitrogen, ethylene was injected into the upper part of the tank, and the pressure was adjusted to 20 kg / cm ² . Stirring was continued, and the inside of the tank was maintained at 55 ° C., and then an aqueous t-butyl hydroperoxide solution was injected from a separate inlet to initiate polymerization. During the reaction, the temperature in the tank was maintained at 55 ° C., and the reaction was completed in 6 hours. An aqueous sodium borate solution was added to the resulting polymerization solution to solidify the polymer, followed by dehydration and drying to obtain acrylic rubber B. This acrylic rubber B is composed of 2.1% by mass of ethylene monomer units, 2.2% by mass of monobutyl maleate monomer units, 68.9% by mass of ethyl acrylate monomer units, acrylic acid-2 -It was a copolymer composition of 26.8 mass% of methoxyethyl monomer units. The monobutyl maleate monomer unit was quantified by dissolving the raw rubber of the copolymer in toluene and performing neutralization titration with potassium hydroxide. For other monomer unit components, a nuclear magnetic resonance spectrum was collected and each component was quantified.

Thus obtained was (A) acrylic rubber A ₁ and A _2, the materials shown in Table 1 were kneaded by using an 8-inch roll to obtain an acrylic rubber composition. In this example, either (O) sodium octyl sulfonate or sodium dodecyl sulfate was used as the (B) alkyl sulfonic acid metal salt and alkyl sulfate metal salt. In addition, (C) any one of sodium stearate, magnesium stearate, aluminum stearate, potassium stearate, calcium stearate, manganese stearate, copper stearate, and zinc stearate was used as the metal stearate.

  In this example, di-o-tolylguanidine and hexamethylenediamine carbamate were used as the (D) vulcanizing agent, and 1.5 parts by weight and 0.6 parts by weight, respectively, with respect to 100 parts by weight of acrylic rubber. Was formulated. The anti-aging agent is Now Royal 445 manufactured by Uniroyal, Carbon Black is Seest 3 manufactured by Tokai Carbon Co., Ltd., Liquid Paraffin is High Coal K-230 manufactured by Kaneda Corporation, Stearylamine is Farmin 80 manufactured by Kao Corporation, Commercially available products were used for the other materials.

  The acrylic rubber composition is heat treated at 170 ° C. for 20 minutes with a steam heating type hot press to form a primary vulcanizate, and then heat treated with hot air (gear oven) at 170 ° C. for 4 hours for acrylic rubber. A vulcanizate of the composition was obtained.

  About the vulcanizate of the obtained acrylic rubber composition, tensile strength, elongation at break, hardness, compression set, and adhesiveness with a metal material were evaluated under the following conditions.

(1) Tensile strength / elongation at break Measured according to JIS K6251.
(2) Hardness Measured using a durometer hardness meter in accordance with JIS K6253.
(3) Compression set test Measured according to JIS K6262 (test condition: 150 ° C. × 70 hours).
(4) Adhesiveness with metal material The adhesiveness to the roll surface at the time of 8-inch roll kneading was evaluated. As for the adhesiveness to the roll surface, “◯” indicates that there is no adhesion and can be easily kneaded, “Δ” indicates that there is a slight adhesion, and “x” indicates that the adhesion is severe. In addition, a brass plate-like material and an acrylic rubber composition were pressure-bonded using a hot press, and the peel strength was measured using a tensile tester. The size of the brass plate-like material is 90 mm long, 25.4 mm wide (1 inch), 2 mm thick. The crimping of the brass plate-like material and the acrylic rubber composition uses a hot press, and the acrylic after pressure bonding. The mold cavity was adjusted so that the thickness of the rubber composition was 1 mm, and the load was 100 tons and 170 ° C. × 20 minutes. The obtained peel test piece was subjected to a peel test at a peel rate of 50 mm / min and a peel direction of 180 °, and the adhesive strength was determined in units of kg / inch.

In Example 1-9, an acrylic rubber _{A 1} as (A) acrylic rubber, with Examples 10-12 In the acrylic rubber _{A 2.}

  In Examples 1 to 8, (B) sodium dodecyl sulfate, which is an alkyl sulfate metal salt, is used in an amount of 2 parts by mass based on 100 parts by mass of the acrylic rubber as at least one compound selected from alkyl sulfonate metal salts and alkyl sulfate metal salts. Partly formulated. In addition, (C) any one of sodium stearate, magnesium stearate, aluminum stearate, potassium stearate, calcium stearate, manganese stearate, copper stearate, and zinc stearate as metal stearate, 100 mass of acrylic rubber 2 parts by mass with respect to parts.

  The vulcanizates of Examples 1 to 8 do not impair the physical properties of tensile strength, elongation at break, hardness, and compression set, have no adhesion to the roll surface, and have a peel strength of 0.22 kg / mm from the brass plate. The adhesion to the metal material is suppressed as compared with the inch and below and the comparative examples described later.

  Of these, in particular, (C) vulcanizates containing magnesium stearate (Example 2) and zinc stearate (Example 8) as the metal stearate have a peel strength from the brass plate of 0.10 kg / inch, 0.09 kg / inch, and the improvement of the adhesiveness to the metal material was particularly remarkable.

  In Example 9, as the at least one compound selected from (B) alkylsulfonic acid metal salt and alkylsulfuric acid metal salt, octylsulfonic acid which is an alkylsulfonic acid metal salt is used instead of sodium dodecylsulfate which is an alkylsulfuric acid metal salt. 2 parts by mass of sodium was blended with 100 parts by mass of acrylic rubber. In addition, (C) 2 parts by mass of magnesium stearate as a metal stearate salt was added to 100 parts by mass of acrylic rubber.

  Also in the vulcanizate of Example 9, good results were obtained in all of the tensile strength, elongation at break, hardness, and compression set, there was no adhesion to the roll surface, and the peel strength from the brass plate was 0. Adhesion to metal material of 15 kg / inch was suppressed.

  In Examples 10 and 11, as the at least one compound selected from (B) alkylsulfonic acid metal salt and alkylsulfuric acid metal salt, sodium dodecylsulfate, which is an alkylsulfuric acid metal salt, was added in an amount of 2 parts by mass with respect to 100 parts by mass of acrylic rubber. Partly formulated. Further, (C) 2 parts by mass of either sodium stearate or magnesium stearate as a metal stearate salt was added to 100 parts by mass of acrylic rubber.

  The vulcanizates of Examples 10 and 11 did not impair the physical properties of tensile strength, elongation at break, hardness, and compression set, had no adhesion to the roll surface, and had a peel strength of 0.14 kg / mm from the brass plate. The adhesion to the metal material is suppressed as compared with the inch and below and the comparative examples described later.

  In Example 12, as the at least one compound selected from (B) an alkylsulfonic acid metal salt and an alkylsulfuric acid metal salt, octylsulfonic acid which is an alkylsulfonic acid metal salt is used instead of sodium dodecylsulfate which is an alkylsulfuric acid metal salt. 2 parts by mass of sodium was blended with 100 parts by mass of acrylic rubber. In addition, (C) 2 parts by mass of magnesium stearate as a metal stearate salt was added to 100 parts by mass of acrylic rubber.

Next, a comparative example will be described. In Comparative Examples 1-7, an acrylic rubber _{A 1} as (A) acrylic rubber and an acrylic rubber _{A 2} Comparative Example 8.

  Comparative Example 1 is a vulcanized product of an acrylic rubber composition that does not contain both (B) at least one compound selected from an alkylsulfonic acid metal salt and an alkylsulfuric acid metal salt, and (C) a stearic acid metal salt. is there.

  In the vulcanizate of Comparative Example 1, the adhesion to the roll surface was severe, the peel strength from the brass plate was as high as 0.37 kg / inch, and the adhesion to the metal material was poor.

  Comparative Examples 2 and 3 are acrylic rubber compositions not blended with (B) at least one compound selected from alkylsulfonic acid metal salts and alkylsulfuric acid metal salts, and (C) stearic acid metal salts. It is a vulcanizate.

  Both the vulcanizates of Comparative Examples 2 and 3 have adhesion to the roll surface, and the peel strength from the brass plate is as high as 0.36 kg / inch and 0.40 kg / inch, respectively, improving the adhesion to metal materials. There wasn't.

  In Comparative Examples 4 and 5, (B) as the at least one compound selected from the alkylsulfonic acid metal salt and the alkylsulfuric acid metal salt, octylsulfonic acid sodium salt, which is an alkylsulfonic acid metal salt, was used, and the compounding amount was examined. did. In the vulcanizate according to Example 9, the blending amount of sodium octylsulfonate is from 2 parts by mass to 100 parts by mass of acrylic rubber, from 0.5 parts by mass (Comparative Example 4), and 5 parts by mass (Comparative Example 5). It was mixed and changed.

  In the vulcanizate of Comparative Example 4, there was adhesion to the roll surface and the peel strength from the brass plate was as high as 0.42 kg / inch, and the adhesion to the metal material was not improved. In the vulcanized product of Comparative Example 5, the compression set was as high as 24%, and the physical properties were impaired.

  In Comparative Examples 6 and 7, (C) magnesium stearate was used as the metal stearate, and the blending amount was examined. In the vulcanized product according to Example 9, the compounding amount of magnesium stearate is from 0.1 parts by mass to 0.05 parts by mass (Comparative Example 6) and 5 parts by mass (Comparative Example 7) with respect to 100 parts by mass of acrylic rubber. ) And blended.

  In the vulcanizate of Comparative Example 6, there was adhesion to the roll surface and the peel strength from the brass plate was as high as 0.33 kg / inch, and the adhesion to the metal material was not improved. Further, in the vulcanized product of Comparative Example 7, the compression set was as high as 33%, and the physical properties were impaired.

  In Comparative Example 8, a vulcanized product of an acrylic rubber composition not blended with (B) at least one compound selected from an alkylsulfonic acid metal salt and an alkylsulfuric acid metal salt, and (C) a stearic acid metal salt It is.

  In the vulcanized product of Comparative Example 8, the adhesion to the roll surface was severe, the peel strength from the brass plate was as high as 0.41 kg / inch, and the adhesion to the metal material was poor.

  As described above, as shown in comparison between the examples and the comparative examples, the acrylic rubber composition of the present invention improves the adhesion with the metal material and improves the workability without impairing the mechanical properties and compression set. An acrylic rubber composition that can be used is obtained.

  The acrylic rubber composition of the present invention provides an acrylic rubber composition that can improve the adhesion to a metal material without impairing mechanical properties and compression set. The acrylic rubber composition and vulcanized product thereof can be used as hose parts, seal parts, and vibration-proof rubber parts.

Claims (10)

  (A) Acrylic rubber is blended with (B) at least one compound selected from alkylsulfonic acid metal salts and alkylsulfuric acid metal salts, (C) stearic acid metal salts, and (D) vulcanizing agents. An acrylic rubber composition.   The acrylic rubber composition according to claim 1, wherein the acrylic rubber (A) is a carboxyl group-containing acrylic rubber.   The acrylic rubber (A) comprises 0.1 to 5% by mass of ethylene monomer units, 1 to 12% by mass of maleic acid monoalkyl ester units, alkyl acrylate esters and / or alkoxyalkyl ester units of acrylic acid 98. The acrylic rubber composition according to claim 2, comprising 9 to 83% by mass.   The acrylic rubber composition according to any one of claims 1 to 3, wherein (B) the alkylsulfonic acid metal salt is sodium alkylsulfonate and the alkylsulfuric acid metal salt is sodium alkylsulfate.   The acrylic rubber composition according to any one of claims 1 to 4, wherein the (C) metal stearate is at least one selected from magnesium stearate and zinc stearate. The (B) at least one compound selected from the alkylsulfonic acid metal salt and the alkylsulfuric acid metal salt is 1 to 4 parts by mass with respect to 100 parts by mass of the acrylic rubber,
The acrylic rubber composition according to any one of claims 1 to 5, wherein the (C) metal stearate is 0.1 to 4 parts by mass with respect to 100 parts by mass of the acrylic rubber.   The acrylic rubber composition according to claim 1, wherein the (D) vulcanizing agent is a guanidine compound and a diamine compound.   The acrylic rubber composition according to claim 7, wherein the diamine compound is hexamethylenediamine carbamate.   The acrylic rubber composition according to any one of claims 1 to 8, comprising at least one monoamine compound selected from primary amine, secondary amine, tertiary amine, and primary amine acetate. object.   A vulcanized product obtained by vulcanizing the acrylic rubber composition according to claim 1.