WO2020261975A1 - Rubber composition, rubber/metal layered product, gasket, and method for producing rubber/metal layered product - Google Patents

Abstract

The present invention can realize: a rubber composition which can prevent metal corrosion caused by a sulfur component and can give a gasket having excellent heat resistance; a rubber/metal layered product; a gasket; and a method for producing a rubber/metal layered product. This rubber composition contains 100 parts by mass of an ethylene-acrylate rubber; 1-200 parts by mass of carbon black; 0.1-20 parts by mass of an amine-based crosslinking agent; and 1-50 parts by mass of a foaming agent.

Description

Manufacturing method of rubber composition, rubber metal laminate, gasket and rubber metal laminate

The present invention relates to a method for producing a rubber composition, a rubber metal laminate, a gasket and a rubber metal laminate. Specifically, the present invention is to produce a rubber composition containing ethylene acrylate rubber, a rubber metal laminate, a gasket and a rubber metal laminate. Regarding the method.

In recent years, rubber compositions containing nitrile rubber such as NBR, H-NBR and modified NBR have been used as gasket materials for automobiles and the like. In these rubber compositions, sulfur components such as sulfur and sulfur compounds are often blended as sulfur-based cross-linking agents, cross-linking accelerators and anti-aging agents. However, in a rubber composition containing nitrile rubber and a sulfur component, sulfur may be liberated from the rubber composition and corrode metals such as illuminated parts. Therefore, a gasket material (for example, see Patent Document 1) and a gasket material (for example, see Patent Document 2) for cross-linking nitrile rubber without using a sulfur component have been proposed.

In the gasket material described in Patent Document 1, by cross-linking nitrile rubber with a quinoid-based cross-linking agent, an electrical component based on the sulfur component in the gasket material when the gasket material is used for the electrical component, etc. Prevents metal corrosion. Further, the gasket material described in Patent Document 2 is based on the sulfur component in the gasket material when the gasket material is used for electronic parts by vulcanizing a carboxyl group-modified nitrile rubber using an epoxy compound as a cross-linking agent. Prevents metal corrosion of electronic parts.

Japanese Unexamined Patent Publication No. 2011-99558 International Publication No. 2013/011918

By the way, in the rubber material of nitrile rubber, a peroxide-based cross-linking agent (peroxide-based cross-linking agent) containing a peroxide for cross-linking the nitrile rubber is also used. However, in the rubber composition containing a peroxide-based cross-linking agent, since the peroxide reacts with oxygen in the air, a gasket having a foam rubber layer using oven vulcanization, which is generally vulcanized in an oven, is used. It cannot be used in manufacturing. Further, the gasket material described in Patent Document 1 and the gasket material described in Patent Document 2 can prevent corrosion of electronic parts and the like based on the sulfur component, while nitrile rubber is used as the rubber material, so that it is not always necessary. Sufficient heat resistance may not be obtained, and it may not be possible to use it in an environment of 100 ° C. or higher.

The present invention has been made in view of such circumstances, and is a rubber composition, a rubber metal laminate, a gasket, and a rubber composition, which can prevent metal corrosion due to a sulfur component and can obtain a gasket having excellent heat resistance. It is an object of the present invention to provide a method for producing a rubber metal laminate.

The rubber composition according to the present invention contains 100 parts by mass of ethylene acrylate rubber, 1 part by mass or more and 200 parts by mass or less of carbon black, 0.1 parts by mass or more and 20 parts by mass or less of an amine-based cross-linking agent, and 1 part by mass of a foaming agent. It is characterized by containing more than 50 parts by mass and less.

According to the rubber composition according to the present invention, since the ethylene acrylate rubber is crosslinked with an amine-based cross-linking agent, it is not necessary to use a sulfur component for cross-linking the ethylene acrylate rubber. As a result, the content of the sulfur component in the rubber composition after cross-linking is significantly reduced in the rubber composition as compared with the case where a sulfur-based cross-linking agent is used, so that the sulfur component in the rubber composition after cross-linking is significantly reduced. It is possible to prevent corrosion of metal members due to the release of sulfur. Further, since the rubber composition contains ethylene acrylate rubber having higher heat resistance than nitrile rubber as a rubber component, it is possible to obtain excellent heat resistance that can be used even in an environment of 100 ° C. or higher. Further, since the rubber composition can prevent the reaction between the amine-based cross-linking agent and air, the ethylene acrylate rubber can be sufficiently cross-linked even when cross-linking is performed in an oven, and the rubber after cross-linking can be sufficiently cross-linked. It is possible to prevent the composition from adhering to the metal member. As a result, the rubber composition can prevent metal corrosion due to the sulfur component, and can obtain a gasket having excellent heat resistance.

In the rubber composition, it is preferable that the amine-based cross-linking agent contains diamines. With this configuration, the ethylene acrylate rubber can be efficiently crosslinked via an amine-based crosslinking agent, so that the heat resistance of the rubber composition after cross-linking is further improved.

In the rubber composition, it is preferable that the foaming agent is at least one selected from the group consisting of a heat expansion type foaming agent and a pyrolysis type foaming agent. With this configuration, the rubber composition is efficiently foamed at the time of cross-linking by oven cross-linking, so that it is possible to obtain a foamed rubber layer having excellent heat resistance.

The rubber-metal laminate according to the present invention is characterized by including a metal member and a foamed rubber layer provided on the metal member and formed by cross-linking the rubber composition.

According to the rubber metal laminate according to the present invention, since the ethylene acrylate rubber is crosslinked with an amine-based cross-linking agent, it is not necessary to use a sulfur component for cross-linking the ethylene acrylate rubber in the rubber composition. As a result, the content of the sulfur component in the foamed rubber layer after cross-linking is significantly reduced in the rubber metal laminate as compared with the case where a sulfur-based cross-linking agent is used. It is possible to prevent corrosion of metal members due to the release of sulfur components. Further, since the rubber metal laminate contains ethylene acrylate rubber having better heat resistance than nitrile rubber as a rubber component, it is possible to obtain excellent heat resistance that can be used even in an environment of 100 ° C. or higher. Further, since the rubber metal laminate can prevent the reaction between the amine-based cross-linking agent and air, the ethylene acrylate rubber can be sufficiently cross-linked even when the rubber composition is cross-linked in an oven. , It is possible to prevent the rubber composition from adhering to the metal member after cross-linking. As a result, the rubber metal laminate can prevent metal corrosion due to the sulfur component and can obtain a gasket having excellent heat resistance.

In the rubber metal laminate, it is preferable that the brass plate, the steel plate and the stainless steel plate do not corrode in the corrosion and stickiness test according to JIS B2403 9.2. With this configuration, the rubber-metal laminate can prevent corrosion of metal members and the like based on the components released from the foamed rubber layer.

In the rubber metal laminate, the hardness change of the pencil hardness of the foamed rubber layer in the scratch hardness test (pencil method) based on JIS K5600-5-4 before and after heat aging at 150 ° C. for 24 hours is 3 points or less. Is preferable. With this configuration, the rubber metal laminate can obtain a foamed rubber layer having excellent heat resistance.

The gasket according to the present invention is characterized by including the above-mentioned rubber metal laminate.

According to the gasket according to the present invention, since the ethylene acrylate rubber is crosslinked with an amine-based cross-linking agent, it is not necessary to use a sulfur component for cross-linking the ethylene acrylate rubber in the rubber composition. As a result, the gasket contains significantly less sulfur component in the foamed rubber layer after cross-linking than when a sulfur-based cross-linking agent is used, so that the sulfur component in the foamed rubber layer after cross-linking is significantly reduced. Corrosion of metal members due to liberation can be prevented. Further, since the gasket contains ethylene acrylate rubber, which has higher heat resistance than nitrile rubber as a rubber component, it is possible to obtain excellent heat resistance that can be used even in an environment of 100 ° C. or higher. Further, since the gasket can prevent the reaction between the amine-based cross-linking agent and air, the ethylene acrylate rubber can be sufficiently cross-linked even when the rubber composition is cross-linked in an oven, and after the cross-linking. Can be prevented from adhering to the metal member of the rubber composition. As a result, the gasket can prevent metal corrosion due to the sulfur component and can have excellent heat resistance.

The method for producing the rubber metal laminate according to the present embodiment includes 100 parts by mass of ethylene acrylate rubber, 1 part by mass or more and 200 parts by mass or less of carbon black, 0.1 parts by mass or more and 20 parts by mass or less of an amine-based cross-linking agent, and a foaming agent. A rubber composition preparation step of mixing 1 part by mass or more and 50 parts by mass or less to obtain a rubber composition, and cross-linking by applying the rubber composition on a metal member and cross-linking by oven cross-linking to obtain a rubber metal laminate. It is characterized by including a step.

According to the method for producing a rubber metal laminate according to the present invention, since the ethylene acrylate rubber is crosslinked with an amine-based cross-linking agent, it is not necessary to use a sulfur component for cross-linking the ethylene acrylate rubber of the rubber composition. As a result, the produced rubber metal laminate has a significantly smaller content of the sulfur component in the foamed rubber layer after cross-linking as compared with the case where a sulfur-based cross-linking agent is used. It is possible to prevent corrosion of the metal member due to the release of the sulfur component in the layer. Further, since the produced rubber metal laminate contains ethylene acrylate rubber having higher heat resistance than nitrile rubber as a rubber component, it is possible to obtain excellent heat resistance that can be used even in an environment of 100 ° C. or higher. Further, since the produced rubber metal laminate can prevent the reaction between the amine-based cross-linking agent and air, the ethylene acrylate rubber is sufficiently cross-linked even when the rubber composition is cross-linked in an oven. It is possible to prevent the rubber composition from adhering to the metal member after cross-linking. As a result, the method for producing a rubber metal laminate can prevent metal corrosion due to a sulfur component and can obtain a rubber metal laminate capable of obtaining a gasket having excellent heat resistance.

According to the present invention, it is possible to realize a method for producing a rubber composition, a rubber metal laminate, a gasket and a rubber metal laminate, which can prevent metal corrosion due to a sulfur component and can obtain a gasket having excellent heat resistance.

FIG. 1 is an explanatory diagram of a corrosion and stickiness test according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be modified as appropriate.

(Rubber composition)
The rubber composition comprises 100 parts by mass of ethylene acrylate rubber, 1 part by mass or more and 200 parts by mass or less of carbon black, 0.1 parts by mass or more and 20 parts by mass or less of an amine-based cross-linking agent, and 1 part by mass or more and 50 parts by mass of a foaming agent. It contains less than one part. Hereinafter, each component of the rubber composition will be described in detail.

Ethylene acrylate rubber (AEM) is a substance having good heat resistance and cold resistance, and is a copolymer of ethylene and acrylic acid esters. The ethylene acrylate rubber includes a binary copolymer of ethylene and acrylic acid ester crosslinked by a peroxide-based cross-linking agent, and a ternary copolymer of ethylene, acrylic acid esters and a carboxyl group-containing unsaturated compound. There is. In the present embodiment, as the ethylene acrylate rubber, a ternary copolymer of ethylene, acrylic acid esters, and a carboxyl group-containing unsaturated compound crosslinked by an amine-based cross-linking agent is used. This ethylene acrylate rubber is a special cross-linked type acrylic rubber material in which a carboxyl group-containing unsaturated compound serves as a cross-linking point.

Examples of acrylate esters include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, and methacrylic acid. Alkyl groups having 1 to 8 carbon atoms such as methyl acetate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, etc. Acrylic acid alkyl ester having, and acrylic acid alkoxy having an alkoxyalkyl group having 1 to 8 carbon atoms such as methoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, n-butoxyethyl acrylate, and ethoxypropyl acrylate. Alkyl esters are used. In general, acrylic acid esters are advantageous in terms of cold resistance when the chain length of the alkyl group is long, and are advantageous in terms of oil resistance when the chain length of the alkyl group is short. As the acrylic acid alkyl ester, for example, ethyl acrylate and n-butyl acrylate are preferable from the viewpoint of the balance between oil resistance and cold resistance.

Examples of the unsaturated compound containing a carboxyl group include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, 2-pentenoic acid, maleic acid, fumaric acid and itaconic acid, and maleic acid, fumaric acid, itaconic acid and citracon. Examples thereof include monoalkyl esters of unsaturated dicarboxylic acids such as acids such as methyl, ethyl, propyl, isopropyl, n-butyl and isobutyl. Among these, as the carboxyl group-containing unsaturated compound, maleic acid mono-n-butyl ester, fumaric acid monoethyl ester, and fumaric acid mono-n-butyl ester are preferable.

The ethylene acrylate rubber may be further copolymerized with another copolymerizable ethylenically unsaturated monomer. Other copolymerizable ethylenically unsaturated monomers include, for example, styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, acrylonitrile, metaacrylonitrile, acrylate amide, vinyl acetate, cyclohexyl acrylate, benzyl acrylate, 2 -Hydroxyethyl acrylate, 4-hydroxybutyl acrylate, ethylene, propylene, piperylene, butadiene, isoprene, pentadiene and the like can be mentioned.

Ethylene acrylate rubber is obtained by emulsifying, suspending, polymerizing, solution-polymerizing, or lumping the above-mentioned ethylene, acrylic acid esters, carboxyl group-containing unsaturated compounds, and other copolymerizable ethylenically unsaturated monomer components. It is obtained by copolymerizing with a known polymerization method such as polymerization.

As the ethylene acrylate rubber, for example, commercially available products such as the trade names "Vamac (registered trademark) GLS" and "Vamac G" (manufactured by DuPont Dow Elastomer) may be used.

The blending amount of the ethylene acrylate rubber in the rubber composition is preferably 40% by mass or more and 90% by mass or less, preferably 45% by mass, from the viewpoint of improving the sealing property and heat resistance of the gasket obtained from the rubber composition. It is more preferably 85% by mass or less, and further preferably 50% by mass or more and 80% by mass or less.

Carbon black is blended in the rubber composition as a filler and a reinforcing material. Examples of carbon black include super wear resistant (SAF: Super Abrasion Finance) carbon black, semi-super wear resistant (ISAF: Intermediate Super Abrasion Furnace) carbon black, high wear resistance (HAF: High Brazil Furnace) carbon black, and carbon black. Hard carbon such as processable channel (EPC: Easy Processing Channel) carbon black, conductive (XCF: Extra Conducive Furnace) carbon black, good extrusion (FEF: Fast Extruding Furnace) carbon black, versatility (G) Purpose (Furnace) carbon black, high stress (HMF: High Modulus Furnace) carbon black, medium reinforcing (SRF: Semi-Reinforcing Furnace) carbon black, fine grain thermal decomposition (FT: Fine Thermal) carbon black, and medium grain thermal decomposition (FT) MT: Medium Thermal) Soft carbon such as carbon black can be mentioned. One type of these carbon blacks may be used alone, or two or more types may be used in combination. Among these, soft carbon is preferable as the carbon black, and among the soft carbons, medium-reinforced carbon black and medium-grain pyrolysis carbon black are more preferable. As the carbon black, a commercially available medium-grain pyrolyzed carbon black product such as the product name "THERMAX (registered trademark) N990 LSR" (manufactured by Cancurve) may be used, and the product name "HTC # SS" (Nittetsu Carbon) may be used. A commercially available product of medium reinforcing carbon black such as (manufactured by Asahi Carbon Co., Ltd.) and the trade name “ASAHI # 50HG” (manufactured by Asahi Carbon Co., Ltd.) may be used.

The amount of carbon black blended is 1 part by mass or more and 200 parts by mass or less with respect to 100 parts by mass of ethylene acrylate from the viewpoint of improving the sealing property and heat resistance of the rubber metal laminate obtained from the rubber composition. It is preferably 5 parts by mass or more and 150 parts by mass or less, more preferably 10 parts by mass or more and 100 parts by mass or less, and further preferably 15 parts by mass or more and 80 parts by mass or less.

The amount of carbon black to be blended is 5% by mass or more and 60% by mass or less with respect to the total mass of the rubber composition from the viewpoint of improving the sealing property and heat resistance of the rubber metal laminate obtained from the rubber composition. It is more preferably 10% by mass or more and 50% by mass or less, and further preferably 15% by mass or more and 45% by mass or less.

When the carbon black is medium-grain thermally decomposed carbon, the blending amount of the carbon black is 100 mass of ethylene acrylate from the viewpoint of improving the sealing property and heat resistance of the rubber metal laminate obtained from the rubber composition. It is preferably 5 parts by mass or more and 50 parts by mass or less, more preferably 10 parts by mass or more and 30 parts by mass or less, and further preferably 15 parts by mass or more and 25 parts by mass or less.

When the carbon black is medium-grain thermally decomposed carbon, the blending amount of the carbon black is the total mass of the rubber composition from the viewpoint of improving the sealing property and heat resistance of the rubber metal laminate obtained from the rubber composition. On the other hand, it is preferably 2.5% by mass or more and 40% by mass or less, more preferably 7.5% by mass or more and 20% by mass or less, and 10% by mass or more and 17.5% by mass or less. Is more preferable.

When the carbon black is medium reinforcing carbon, the blending amount of the carbon black is 100 parts by mass of ethylene acrylate from the viewpoint of improving the sealing property and heat resistance of the rubber metal laminate obtained from the rubber composition. On the other hand, it is preferably 10 parts by mass or more and 200 parts by mass or less, more preferably 25 parts by mass or more and 100 parts by mass or less, and further preferably 45 parts by mass or more and 65 parts by mass or less.

When the carbon black is a medium reinforcing carbon, the blending amount of the carbon black is the total mass of the rubber composition from the viewpoint of improving the sealing property and heat resistance of the rubber metal laminate obtained from the rubber composition. On the other hand, it is preferably 5% by mass or more and 70% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and further preferably 15% by mass or more and 45% by mass or less.

<Crosslinking agent>
The cross-linking agent (vulcanizing agent) forms a cross-linking bond between the ethylene acrylate rubbers. In the present embodiment, an amine-based cross-linking agent is used as the cross-linking agent. As the amine-based cross-linking agent, diamines are preferable from the viewpoint of easily forming a cross-linked structure with a carboxyl group which is a cross-linking point derived from a carboxyl group-containing unsaturated compound contained in ethylene acrylate rubber.

The diamines may be aliphatic or aromatic. Examples of diamines include hexamethylenediamine, hexamethylenediamine carbamate, N, N'-dicinnamylidene-1,6-hexanediamine, 4,4'-methylenebis (cyclohexylamine) carbamate, and 4,4'-methylenedianiline. , 4,4'-Oxyphenyldiphenylamine, m-phenylenediamine, p-phenylenediamine, 4,4'-methylenebis (o-chloroaniline), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4 , 4'-(m-phenylenediisopropyridene) dianiline, 4,4'-(p-phenylenediisopropyridene) dianiline, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 4, 4'-diaminobenzanilide, 4,4'-bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, hexamethylenediamine-cinnamaldehyde adduct, hexamethylenediamine-dibenzoate salt, etc. Can be mentioned. Among these, amine-based cross-linking agents include hexamethylenediamine carbamate, N, N'-dicinnamylidene-1,6-hexanediamine, 4,4'-methylenebis (cyclohexylamine) carbamate, and 4,4'-diaminodiphenyl ether. At least one kind of alkylenediamines selected from the above group is preferable, and alkylenediamines containing hexamethylenediamine carbamate are more preferable. Examples of the amine-based cross-linking agent include the trade name "Cheminox AC6-66 (hexamethylenediamine carbamate)" (manufactured by Unimatec) and the trade name "Diak No. 1 (hexamethylenediamine carbamate)" (Dupont Dow. Elastomer), product name "Diak No. 3: N, N'-dicinnamilyden-1,6-hexanediamine" (Dupont Dow Elastomer), product name "Diak No. 4 (4,4'-" Commercially available products such as "methylenebis (cyclohexylamine) carbamate)" (manufactured by DuPont Dow Elastomer) and trade name "DADPE: (4,4'-diaminodiphenyl ether)" (manufactured by Sun Chemical) may be used.

The blending amount of the amine-based cross-linking agent is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of ethylene acrylate rubber from the viewpoint of improving the cross-linking density and improving the heat resistance of the rubber composition. It is more preferable, it is more preferably 0.5 parts by mass or more and 10 parts by mass or less, and further preferably 1 part by mass or more and 7.5 parts by mass or less.

The amount of the amine-based cross-linking agent blended is based on 100 parts by mass of ethylene acrylate rubber with respect to the total mass of the rubber composition from the viewpoint of improving the cross-linking density and improving the heat resistance of the rubber composition. It is preferably 0.5% by mass or more and 10% by mass or less, more preferably 0.75% by mass or more and 5% by mass or less, and further preferably 1% by mass or more and 3% by mass or less.

The amine-based cross-linking accelerator promotes the formation of a cross-linking reaction of ethylene acrylate rubber by the amine-based cross-linking agent. Examples of the amine-based cross-linking accelerator include amine-based cross-linking accelerators such as a tertiary amine complex adsorbed on an amorphous silica carrier. As the amine-based cross-linking accelerator, for example, a commercially available product such as "Vulcofac (registered trademark) ACT-55 (amination derivative: tertiary amine complex adsorbed on an amorphous silica carrier)" (manufactured by DuPont) is used. You may.

The blending amount of the amine-based cross-linking accelerator is, for example, 0.1 part by mass or more and 15 parts by mass or less with respect to 100 parts by mass of ethylene acrylate rubber from the viewpoint of improving the cross-linking density and improving the heat resistance of the rubber composition. It is more preferably 0.5 parts by mass or more and 10 parts by mass or less, and further preferably 1 part by mass or more and 5 parts by mass or less.

The blending amount of the amine-based cross-linking accelerator is, for example, 0.1% by mass or more and 10% by mass or less with respect to the total mass of the rubber composition from the viewpoint of improving the cross-linking density and improving the heat resistance of the rubber composition. It is more preferably 0.5% by mass or more and 5% by mass or less, and further preferably 0.75% by mass or more and 3% by mass or less.

As the foaming agent, various foaming agents can be used as long as the effects of the present invention are exhibited. As the foaming agent, for example, various thermal expansion type foaming agents and various thermal decomposition type foaming agents are used. Examples of the heat-expandable foaming agent include heat-expandable microcapsules in which a low-boiling hydrocarbon expansion agent is encapsulated. Moreover, as a pyrolysis type foaming agent, for example, a chemical foaming agent containing an organic compound or an inorganic compound having a pyrolysis property can be mentioned. Examples of the chemical foaming agent include a chemical foaming agent containing an organic compound such as azodicarboxylic amide, N, N'-dinitrosopentamethylenetetramine and N, N'-dinitrosopentamethylenetetramine, and sodium hydrogencarbonate. Examples thereof include chemical foaming agents containing the above inorganic compounds. Among these, as the foaming agent, a chemically expandable microcapsule and a chemical foaming agent containing azodicarbonamide are preferable from the viewpoint of improving the sealing property and heat resistance of the gasket obtained from the rubber composition.

As the foaming agent, for example, the trade name "Advancel EM304 (thermally expandable microcapsule)" (manufactured by Sekisui Chemical Co., Ltd.) and the trade name "Vinihole AC # 3 (azodicarbonamide)" (manufactured by Eiwa Kasei Co., Ltd.) Goods may be used.

The amount of the foaming agent to be blended is 100 parts by mass of ethylene acrylate rubber from the viewpoint of efficiently foaming the rubber composition at the time of crosslinking to obtain a foamed rubber layer having excellent sealing properties and heat resistance of the gasket using the rubber composition. On the other hand, it is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 45 parts by mass or less, and further preferably 7.5 parts by mass or more and 40 parts by mass or less.

The amount of the foaming agent to be blended is set to the total mass of the rubber composition from the viewpoint of efficiently foaming the rubber composition at the time of crosslinking to obtain a foamed rubber layer having excellent sealing properties and heat resistance of the gasket using the rubber composition. On the other hand, it is preferably 1% by mass or more and 50% by mass or less, more preferably 2.5% by mass or more and 30% by mass or less, and further preferably 5% by mass or more and 25% by mass or less.

Further, the rubber composition may contain a filler such as calcium carbonate and silica, if necessary. As the calcium carbonate, various calcium carbonates such as heavy calcium carbonate and synthetic calcium carbonate can be used.

Further, the rubber composition may contain an auxiliary agent generally used in the rubber industry, such as zinc oxide, a plasticizer, stearic acid, an antiaging agent, and paraffin wax, if necessary.

The plasticizer functions as a processing aid that appropriately lowers the viscosity of the rubber composition and improves workability. Examples of the plasticizer include commercially available products such as the trade name "Mezamol (registered trademark)" (manufactured by LANXESS). The blending amount of the plasticizer is, for example, 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the rubber component.

As the stearic acid, for example, a commercially available product such as the trade name "DTST" (manufactured by Miyoshi Oil & Fat Co., Ltd.) may be used. The blending amount of stearic acid is, for example, 0.1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the rubber component.

As the anti-aging agent, for example, a commercially available product such as the trade name "Nocrack (registered trademark) CD" (4,4'-bis (α, α-dimethylbenzyl) diphenylamine) may be used. The blending amount of the anti-aging agent is, for example, 0.1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the rubber component.

(Rubber metal laminate)
Next, the rubber metal laminate according to the present embodiment will be described. The rubber-metal laminate according to the present embodiment includes a metal member and a foamed rubber layer provided on the metal member and formed by cross-linking the rubber composition. This rubber metal laminate can be suitably used as a sealing member for various gaskets and the like.

In the rubber metal laminate according to the present embodiment, the foamed rubber layer is the hardness of the pencil hardness in the scratch hardness test (pencil method) according to JIS K5600-5-4 before and after heat aging at 150 ° C. for 24 hours. The change is preferably 3 points or less. This makes it possible to obtain a foamed rubber layer having excellent heat resistance in the rubber metal laminate. The hardness change here is the amount of change in pencil hardness. For example, when the pencil hardness before heat aging at 150 ° C. for 24 hours is 6B and the pencil hardness after heat aging at 150 ° C. for 24 hours is 5B, the hardness change is 1. It will be a point. Further, when the pencil hardness before heat aging at 150 ° C. for 24 hours is F and the pencil hardness after heat aging at 150 ° C. for 24 hours is H, the hardness change is 1 point. The hardness change of the pencil hardness is more preferably 2 points or less, and further preferably 1 point or less.

The foaming ratio of the foamed rubber layer is preferably 2 times or more, more preferably 2.5 times or more, from the viewpoint of improving the sealing property of a sealing member such as a gasket using a rubber metal laminate. It is more preferably 3 times or more, more preferably 20 times or less, further preferably 10 times or less, and further preferably 7.5 times or less. The foaming ratio here is calculated based on the following formula (1).
Foaming ratio = (thickness of rubber metal laminate after cross-linking-steel plate thickness) / (thickness of rubber metal laminate before cross-linking-steel plate thickness) ... Equation (1)

In the rubber laminate according to the present embodiment, it is preferable that the brass plate, the steel plate and the stainless steel plate do not corrode in the corrosion and stickiness test according to JIS B2403 9.2. This makes it possible for the rubber-metal laminate to prevent corrosion of metal members and the like based on the components released from the foamed rubber layer.

Further, in the rubber laminate according to the present embodiment, it is preferable that transfer (stickiness) does not occur on the brass plate, the steel plate and the stainless steel plate in the corrosion and stickiness test according to JIS B2403 9.2. This makes it possible for the rubber-metal laminate to prevent the transfer of the rubber component from the foamed rubber layer to the metal member or the like. Hereinafter, various components of the rubber metal laminate according to the present embodiment will be described in detail.

As the metal member, for example, a metal plate such as iron, stainless steel, aluminum, magnesium, zinc-plated steel and copper is used. As the iron, for example, cold-rolled steel sheet (SPCC: Steel Plate Cold Commercial), high-strength steel sheet, mild steel sheet and the like are used. Further, as the stainless steel, for example, a stainless steel plate such as a ferrite type, a martensitic type, or an austenitic type can be used. Specific examples of stainless steel include SUS304, SUS301, SUS301H and SUS430. As aluminum, an aluminum plate, an aluminum die-cast plate, or the like is used.

It is preferable to use the metal member in a state where the surface is degreased by an alkaline degreasing treatment or the like. Further, the metal member is used by roughening the metal surface by shot blasting, Scotch bride (registered trademark), hairline, dull finish or the like, if necessary.

It is preferable that the surface of the metal member to be adhered to the adhesive is surface-treated. The base treatment is not particularly limited, and a known base treatment can be used. As the base treatment, when iron materials such as cold-rolled steel sheets and high-tensile steel sheets and stainless steel materials are used as metal members, chemical conversion treatment methods using various chemical conversion treatment agents, electroplating with metals such as zinc, and hot-dip plating are performed. Various plating methods such as are preferable. Examples of the chemical conversion treatment agent for metal members include phosphoric acid-based treatment agents such as zinc phosphate treatment agents and iron phosphate treatment agents, and coating-type chromate treatment agents. As the chemical conversion treatment agent, a chromium-free chemical conversion treatment agent that does not substantially contain chromium is preferable from the viewpoint of environmental protection.

The base treatment of the metal member with the chemical conversion treatment agent is performed by contacting the metal member with the chemical conversion treatment agent by a known liquid contact method such as spraying, spraying, dipping, brush coating and a roll coater. In the case of a reactive chemical conversion treatment agent, it is required to secure the time and temperature required for the reaction.

In the rubber metal laminate, it is preferable that a primer layer is formed on the metal member in addition to the base treatment or instead of the base treatment. By applying a base treatment or providing a primer layer, the adhesiveness between the rubber layer and the metal member in the rubber metal laminate can be improved, and the heat resistance and water resistance of the rubber metal laminate can be significantly improved. it can. Further, the rubber metal laminate can be suitably used as a gasket which is a laminated composite metal in which a rubber metal laminate and another metal plate or the like are laminated by subjecting a base treatment or forming a primer layer. it can.

The primer layer includes silicon compounds, metal compounds such as titanium, zirconium, vanadium, aluminum, molybdenum, tungsten, manganese, zinc and cerium, inorganic compounds such as these oxides, silicone resins, phenolic resins and epoxies. It can be provided by a resin, an organic compound such as polyurethane, or the like. As the primer layer, a commercially available primer solution may be used, or other primer solutions according to various known techniques can be used for the primer layer.

The primer layer is provided by a primer solution in which a raw material containing the above-mentioned various inorganic compounds and organic compounds is dissolved or dispersed in an organic solvent or an aqueous solvent. Examples of the organic solvent that can be used include alcohols such as methanol, ethanol and isopropyl alcohol, and ketones such as acetone and methyl ethyl ketone. The primer solution may be prepared as an aqueous solution using an aqueous solvent as long as the liquid stability is maintained.

The obtained primer solution is applied onto a metal plate by spraying, dipping, brushing, a roll coater, or the like. Then, the primer layer is provided by drying the primer solution applied on the metal plate at room temperature or warm air, or by baking the primer solution.

The adhesive adheres the rubber layer and the metal member. As the adhesive, generally commercially available adhesives such as phenol resin, epoxy resin, polyurethane resin and silane are used. These adhesives can be appropriately selected depending on the use of the rubber metal laminate.

In the rubber metal laminate, it is preferable that the metal plate and the rubber layer are adhered to each other via at least one selected from the group consisting of phenol resin and epoxy resin. As a result, the rubber-metal laminate improves the adhesiveness between the metal plate and the rubber layer, so that the sealing property of the member to be sealed when used for various gaskets and the like is further improved.

As the phenol resin, for example, a novolak type phenol resin and a resol type phenol resin are used. As the novolak type phenol resin and the resol type phenol resin, one type may be used alone, or two or more types may be used in combination. Further, as the adhesive, one containing two types of phenolic resins, a novolak type phenolic resin and a resole type phenolic resin, and uncrosslinked nitrile rubber may be used.

As the novolak type phenol resin, one obtained by condensation reaction of phenols and formaldehyde in the presence of an acid catalyst is used. As the phenols, for example, at least one of the o-position and the p-position with respect to the phenolic hydroxyl group such as phenol, p-cresol, m-cresol, p-third butylphenol, p-phenylphenol, and bisphenol A. Those having two or three substitutable hydrogen atoms are used. One of these phenolic resins may be used alone, or two or more thereof may be used in combination. As the acid catalyst, for example, oxalic acid, hydrochloric acid, maleic acid and the like are used. Among these, as the novolak type phenol resin, those having a melting point of 80 ° C. or higher and 150 ° C. or lower are preferable from the viewpoint of improving the adhesiveness between the metal plate and the rubber layer, and obtained by using m-cresol and formaldehyde. Those having a melting point of 120 degrees or higher are more preferable.

As the resol type phenol resin, one obtained by condensation reaction of phenols and formaldehyde in the presence of a base catalyst is used. Examples of phenols include at least one of the o- and p-positions with respect to phenolic hydroxyl groups such as phenol, p-cresol, m-cresol, and p-third butylphenol, p-phenylphenol, and bisphenol A. The one having 2 or 3 replaceable hydrogen atoms is used. One of these phenolic resins may be used alone, or two or more thereof may be used in combination. As the base catalyst, for example, alkali metal hydroxides such as ammonia and sodium hydroxide, magnesium hydroxide, sodium carbonate and the like are used.

Examples of the epoxy resin include bisphenol A type, cresol novolac type, biphenyl type, and brominated epoxy resin. One of these epoxy resins may be used alone, or two or more of these epoxy resins may be used in combination. Among these epoxy resins, bisphenol A type epoxy resin and cresol novolac type epoxy resin are preferable from the viewpoint of easy availability of commercially available products and excellent heat resistance. Examples of the bisphenol A type epoxy resin include DIC's product names "EPICON 860", "EPICON 1055", "EPICON 2050", "EPICON 3050", product names "EPICON 4050", "EPICON 7050", and "EPICON". Commercially available products such as "HM-091" may be used. As commercially available cresol novolac type epoxy resins, for example, DIC's trade names "EPICLON N-660", "EPICLON N-670", "EPICLON N-680", "EPICLON N-690", etc. Commercially available products may be used.

The above-mentioned various adhesives are used as a solution dissolved in an organic solvent. As the organic solvent, for example, ketones such as methyl ethyl ketone and methyl isobutyl ketone, aromatic hydrocarbons such as toluene and xylene, and the like are used. One of these organic solvents may be used alone, or two or more of these organic solvents may be used in combination.

The adhesive is preferably blended in a ratio of 10 parts by mass or more and 1000 parts by mass or less, and 60 parts by mass or more and 400 parts by mass or less, with respect to 100 parts by mass of the novolak type phenol resin. It is more preferable to do so. By using 1000 parts by mass or less of the resol type phenol resin with respect to 100 parts by mass of the novolak type phenol resin, it is possible to prevent a decrease in the adhesiveness of the rubber layer, and the adhesive should be 10 parts by mass or more. This makes it possible to prevent a decrease in adhesiveness with the surface of the metal member.

The adhesive is preferably provided on the metal plate on which the primer layer is formed from the viewpoint of improving the adhesiveness between the metal member and the rubber layer. Further, the adhesive layer may be provided as one layer or may be provided as multiple layers. In the adhesive layer, a phenol-based adhesive layer containing a Yuki metal compound is formed on a primer layer provided on a metal member, and then a phenol-based adhesive layer is further provided on the adhesive layer to spread an adhesive in multiple stages. It may be provided as a structure. By forming the adhesive layer having such a multi-stage structure, the adhesiveness between the primer layer and the rubber layer can be further strengthened.

The adhesive is prepared as an adhesive solution having a solid content concentration of 1% by mass or more and 10% by mass or less by using a ketone-based organic solvent such as acetone, methyl ethyl ketone and methyl isobutyl ketone and a mixed solvent thereof. The adhesive solution is applied onto the metal member and then dried and baked for about 1 minute or more and 30 minutes under the conditions of 100 ° C. or higher and 250 ° C. or lower to form an adhesive layer. The amount of the adhesive applied is preferably in the range of 50 mg / m ² or more and 2000 mg / m ² or less after the drying and baking treatment after the application. Further, the adhesive is preferably applied so that the thickness of the adhesive layer after drying is 0.5 μm or more and 5 μm or less.

Further, the foam rubber layer may contain other rubber components as long as the effects of the present invention are exhibited. Examples of other rubber components include nitrile rubber (NBR: Nitrile Butadiene Rubber), which is an acrylonitrile-butadiene copolymer, hydride nitrile rubber (H-NBR) in which the unsaturated bond portion of nitrile rubber is hydrogenated, and nitrile rubber. Examples thereof include modified nitrile rubber modified from the above, and various rubber materials such as fluorine rubber.

The thickness of the foamed rubber layer after cross-linking is preferably 10 μm or more and 700 μm or less, and more preferably 20 μm or more and 600 μm or less, from the viewpoint of obtaining sufficient sealing properties and heat resistance when used as a gasket. It is more preferably 30 μm or more and 500 μm or less.

The rubber metal laminate according to the above embodiment contains a metal member such as a stainless steel plate, a rubber component, carbon black, an amine-based cross-linking agent and a foaming agent, and if necessary, a cross-linking accelerator, calcium carbonate, silica. , A plasticizer and various auxiliaries, and a rubber composition kneaded with a sealed kneader such as an intermix, a kneader, or a Banbury mixer or an open roll is dissolved in an organic solvent to produce the rubber composition. In the rubber metal laminate, after applying the rubber composition to the surface-treated metal member as necessary via an adhesive layer, for example, the rubber composition is applied at 160 ° C. or higher and 250 ° C. or lower for 0.5 minutes or longer. It is produced by forming a foam rubber layer by cross-linking in an oven under conditions of about 30 minutes or less. In the rubber metal laminate, a resin-based or graphite-based coating agent may be applied onto the rubber layer from the viewpoint of preventing rubber adhesion.

The method of applying the rubber composition onto the metal member is not particularly limited as long as the rubber composition can be applied onto the metal member. Examples of the rubber composition include a spray method, a dipping method, a roll coating method, and a dispenser method.

At the time of manufacturing the rubber composition and applying it on the metal member, an organic solvent may be added to the rubber composition to adjust the viscosity, if necessary. The organic solvent is not particularly limited as long as the viscosity of the rubber composition can be adjusted to a desired viscosity. Examples of the organic solvent include ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, aromatic hydrocarbon solvents such as toluene, and ester solvents such as ethyl acetate. One of these organic solvents may be used alone, or two or more of them may be used in combination.

As described above, according to the above embodiment, since the ethylene acrylate rubber is crosslinked with the amine-based cross-linking agent, it is not necessary to use the sulfur component for the cross-linking of the ethylene acrylate rubber. As a result, the content of the sulfur component in the rubber composition after cross-linking is significantly reduced in the rubber composition as compared with the case where a sulfur-based cross-linking agent is used, so that the sulfur component in the rubber composition after cross-linking is significantly reduced. It is possible to prevent corrosion of metal members due to the release of sulfur. Further, since the rubber composition contains ethylene acrylate rubber having better heat resistance than nitrile rubber as a rubber component, it is possible to obtain excellent heat resistance that can be used even in an environment of 100 ° C. or higher, and it can be applied to heat resistant applications. Is also possible. Further, since the rubber metal laminate can prevent the reaction between the amine-based cross-linking agent and air, the ethylene acrylate rubber can be sufficiently cross-linked even when the rubber composition is cross-linked in an oven. , It is possible to prevent the rubber composition from adhering to the metal member after cross-linking. Since the rubber metal laminate is provided with the foamed rubber layer by the rubber composition containing the foaming agent, the compression ratio when used for the gasket can be increased due to the large number of air bubbles existing in the foamed rubber layer, and the surface roughness can be increased. Excellent sealing performance under rough flanges and low surface pressure. As a result, the rubber composition can prevent metal corrosion due to the sulfur component, and can obtain a gasket having excellent heat resistance.

Hereinafter, the present invention will be described in more detail based on examples carried out to clarify the effects of the present invention. The present invention is not limited to the following examples and comparative examples.

The present inventor produced a rubber metal laminate according to the above embodiment, and evaluated the produced rubber metal laminate by performing a compression test. Hereinafter, the contents investigated by the present inventor will be described.

(Example 1)
<Preparation of sample for evaluation of foaming characteristics>
A cold-rolled steel sheet (SPCC: Steel Plate Cold Commercial) having a thickness of 600 μm was subjected to chemical conversion treatment by zinc phosphate treatment. Next, a primer solution obtained by diluting a primer (Chemlock (registered trademark) AP133, manufactured by LOAD) with methanol to a solid content of 2% by mass was immersed and applied to a cold-rolled steel sheet subjected to chemical conversion treatment, and the mixture was applied at 200 ° C. for 10 minutes. The heat treatment was carried out to provide a primer layer having a thickness of 1 μm or less on the cold-rolled steel sheet. Next, on the primer layer, 97% by mass of a phenol resin adhesive (Sixon 715A, manufactured by Roam & Haas) and 3% by mass of a hexamethylenetetramine-containing curing agent B (Sixon 715B, manufactured by Roam & Haas) were added to 440% by mass of methyl ethyl ketone. After diluting to a solid content concentration of 6% by mass with a mixed solvent of 110 parts by mass of methanol and parts and dipping coating, heat treatment was performed at 170 ° C. for 5 minutes to provide an adhesive layer.

Next, 100 parts by mass of ethylene acrylate rubber (trade name "VAMAC (registered trademark) GLS", manufactured by DuPont), carbon black A (medium grain thermal decomposition carbon black: trade name "THERMAX (registered trademark) N990 LSR," can 20 parts by mass of Curve Co., Ltd., 2 parts by mass of stearic acid (trade name "DTST", manufactured by Miyoshi Oil & Fat Co., Ltd.), anti-aging agent (4,4'-bis (α, α-dimethylbenzyl) diphenylamine: trade name "Nocrack" (Registered trademark) CD ”, manufactured by Rankses, 2 parts by mass, amine-based cross-linking agent (hexamethylenediamine carbamate: trade name“ Cheminox AC6-66 ”, manufactured by Unimatec), 2 parts by mass, amine-based cross-linking accelerator (amorphic) Tertiary amine complex adsorbed on quality silica carrier: trade name "Balcofuck ACT-55", manufactured by DuPont) 1.6 parts by mass, and thermal decomposition foaming agent (azodicarboxylic amide: trade name "Vinihole AC # 3" , Eiwa Kasei Co., Ltd.) 30 parts by mass was kneaded with a kneader, an open roll, or the like to obtain a rubber composition. The obtained rubber composition is dissolved in a mixed solvent mixed at a mass ratio of methyl ethyl ketone: toluene = 2: 8 so that the solid content concentration of the rubber composition is 25% by mass or more and 35% by mass or less. The rubber composition solution was prepared. Next, the rubber composition solution was uniformly applied onto the adhesive layer on one main surface of the cold-rolled steel sheet, and then dried at 60 ° C. for 5 minutes to evaluate the foaming characteristics of the rubber metal laminate. Was produced.

<Evaluation of foaming characteristics>
After measuring the thickness of the entire rubber metal laminate before cross-linking and the thickness of the cold-rolled steel sheet of the prepared sample for evaluation of foaming characteristics, the entire rubber metal laminate after cross-linking was crosslinked at 200 ° C. for 3 minutes. The thickness was measured. The foaming ratio was calculated by the following formula (1).
Foaming ratio = (thickness of rubber metal laminate after cross-linking-steel plate thickness) / (thickness of rubber metal laminate before cross-linking-steel plate thickness) ・ ・ ・ Equation (1)

<Heat resistance evaluation>
After cross-linking the sample for evaluation of foaming characteristics, the heat resistance is evaluated by measuring the pencil hardness by the hand-scratch method in accordance with JIS K5600-5-4 "Mechanical properties of coating film-scratch hardness (pencil method)". Carried out. As the pencil, a pencil with a hardness of 6B to 6H (manufactured by Mitsubishi Pencil Co., Ltd.) certified by the Japan Paint Certification Association was used. The pencil hardness was determined by the hardness type measured by starting the measurement of the scratch hardness from the pencil having the highest hardness and gradually decreasing the hardness of the pencil until the foam rubber layer was no longer scraped. In this example, since the rubber layer of the rubber metal laminate is foam rubber, the determination was made based on the following criteria.
・ When scratched with a pencil, it was judged that the dents where the scratched part simply left a white linear mark were not scraped.
-When scratching with a pencil, if the scratched part is scratched by stick slip, it is judged that the rubber has been scraped.
-If the rubber at the scratched part is peeled off when scratched with a pencil, it is judged that the rubber has been scraped.
The scratch hardness was measured before and after the heat route at 150 ° C. for 24 hours, and those having a small degree of change in pencil hardness due to heat aging were judged to have good heat resistance. For example, when the hardness before aging was 6B and the hardness after aging was 3B, the degree of change in hardness was evaluated as +3 points. The heat resistance evaluation was evaluated based on the following evaluation criteria.
◯: Hardness change is within +2 points ×: Hardness change is +3 points or more

<Corrosiveness evaluation and stickiness evaluation>
A primer solution obtained by diluting a primer (Chemlock (registered trademark) AP133, manufactured by LOAD) with methanol to a solid content of 2% by mass was immersed and coated on a 200 μm-thick stainless steel sheet (model number “SUS301H”), and 10 at 200 ° C. A primer layer was provided on the cold-rolled steel sheet by heat treatment for 1 minute. Next, on the primer layer, 97% by mass of a phenol resin adhesive (Sixon 715A, manufactured by Roam & Haas) and 3% by mass of a hexamethylenetetramine-containing curing agent B (Sixon 715B, manufactured by Roam & Haas) were added to 440% by mass of methyl ethyl ketone. After diluting to a solid content concentration of 6% by mass with a mixed solvent of 110 parts by mass of methanol and parts and dipping coating, heat treatment was performed at 170 ° C. for 5 minutes to provide an adhesive layer.

Next, the rubber composition solution used when preparing the sample for evaluating the foaming characteristics was applied so that the thickness of the foamed rubber layer before cross-linking was 80 μm or more and 100 μm on the adhesive layer on one main surface of the stainless steel sheet. Was evenly applied and dried at 60 ° C. for 5 minutes. Next, the rubber composition solution was uniformly applied onto the adhesive layer on the other main surface of the stainless steel sheet so that the thickness of the foamed rubber layer before cross-linking was 80 μm or more and 100 μm, and the thickness was 5 at 60 ° C. Allowed to dry for minutes. Next, a stainless steel plate provided with a foam rubber layer was crosslinked in an oven at 200 ° C. for 3 minutes to prepare a sample for evaluation of the corrosiveness and stickiness of the rubber metal laminate.

Corrosion evaluation and stickiness evaluation were carried out in accordance with JIS B2403 9.2 "Corrosion and stickiness test" used in V packing. The prepared evaluation sample was cut into a width of 25 mm and a length of 50 mm, and four test pieces were taken out. Sandpaper the surface of three types of metal plates: brass plate (model number "C2801"), steel plate (model number "SS400") and stainless steel plate (model number "SUS304") with a thickness of 3 mm, width of 25 mm and length of 50 mm. After polishing well with # 400), it was degreased and washed in hexane by ultrasonic cleaning, and the test pieces and metal plates were alternately brought into close contact with each other and stacked and sandwiched.

FIG. 1 is an explanatory diagram of a corrosion and stickiness test according to an embodiment of the present invention. As shown in FIG. 1, in the corrosion and stickiness test, the first test piece 100-1 to the fourth test piece 100-4 of the rubber metal laminated plate were used. The first test pieces 100-1 to the fourth test pieces 100-4 are provided on one main surface of the stainless steel plates 101-1 to 101-4 and the stainless steel plates 101-1 to 101-4, respectively. The rubber layers 101a-1 to 104a-1 and the second rubber layers 101b-1 to 104b-1 provided on the other main surface of the stainless steel plates 101-1 to 101-4 are provided. In the corrosion and stickiness test, the brass plate 201 was laminated on the first rubber layer 102a-1 of the first test piece 100-1, and the second rubber layer 102b- of the second test piece 100-2 was laminated on the brass plate 201. 2 is laminated, the steel plate 202 is laminated on the first rubber layer 102a-2 of the second test piece 100-2, and the second rubber layer 102b-3 of the third test piece 100-3 is laminated on the steel plate 202. , A test piece in which a stainless steel plate 203 is laminated on the first rubber layer 102a-3 of the third test piece 100-3, and a second rubber layer 102b-4 of the fourth test piece 100-4 is laminated on the stainless steel plate 203. 10 was used. After the test piece 10 was placed in a constant temperature bath kept at 70 ° C. for 24 hours, the corrosion and adhesive states of the brass plate 201, the steel plate 202, and the stainless steel plate 203 were visually confirmed, and the evaluation criteria were as follows. Evaluated. The evaluation results are shown in Table 1 below.
<Corrosiveness evaluation criteria>
◯: No corrosion on the metal plate ×: Corrosion on the metal plate <Criteria for evaluation of stickiness>
◯: No transfer to metal plate (sticky) ×: Transfer to metal plate (sticky)

(Example 2)
Same as Example 1 except that 9 parts by mass of a thermal expansion foaming agent (microcapsule: trade name "Advancel (registered trademark) EM304", manufactured by Sekisui Chemical Co., Ltd.) was used instead of the pyrolysis foaming agent. A rubber metal laminate was prepared, and the foaming characteristics, heat resistance, and corrosiveness were evaluated. The evaluation results are shown in Table 1 below.

(Example 3)
A rubber metal laminate was prepared in the same manner as in Example 2 except that the blending amount of the heat-expandable foaming agent was 16 parts by mass, and the foaming characteristics, heat resistance and corrosiveness were evaluated. The evaluation results are shown in Table 1 below.

(Example 4)
Furthermore, 54 parts by mass of carbon black B (medium reinforcing (SRF: Semi-Reinforcing Furnace) carbon black: trade name "HTC # SS", manufactured by Nittetsu Carbon Co., Ltd.) was used, and a heat-expandable foaming agent was blended. A rubber metal laminate was prepared in the same manner as in Example 3 except that the amount was 20 parts by mass, and foaming characteristics evaluation, heat resistance evaluation, and corrosiveness evaluation were carried out. The evaluation results are shown in Table 1 below.

(Example 5)
A rubber metal laminate was prepared in the same manner as in Example 4 except that the blending amount of the heat-expandable foaming agent was 30 parts by mass, and foaming characteristics evaluation, heat resistance evaluation, and corrosiveness evaluation were carried out. The evaluation results are shown in Table 1 below.

(Example 6)
Except that the amount of the amine-based cross-linking agent was 5 parts by mass, the amount of the amine-based cross-linking accelerator was 2 parts by mass, and the amount of the heat-expandable foaming agent was 35 parts by mass. A rubber metal laminate was prepared in the same manner as in Example 5, and foaming characteristics evaluation, heat resistance evaluation, and corrosiveness evaluation were carried out. The evaluation results are shown in Table 1 below.

(Example 7)
A rubber metal laminate was prepared in the same manner as in Example 6 except that the blending amount of the heat-expandable foaming agent was 20 parts by mass, and the foaming characteristics, heat resistance and corrosiveness were evaluated. The evaluation results are shown in Table 1 below.

(Comparative Example 1)
Using 100 parts by mass of nitrile rubber (high nitrile: bonded acrylonitrile content 41.5%: trade name "JSR N220S", manufactured by JSR) instead of ethylene acrylate rubber, zinc oxide (manufactured by Shodo Chemical Co., Ltd.) 5 A part by mass was used, a plasticizer (non-phthalic acid-based plastic agent: trade name "Mezamol", manufactured by Rankses) was used, and a sulfur-based cross-linking agent (trade name) was used instead of the amine-based cross-linking agent. Using 1.2 parts by mass of "colloidal sulfur A" (manufactured by Tsurumi Chemical Co., Ltd.), instead of the amine-based accelerator, sulfur-based cross-linking accelerator A (dibenzothiazil disulfide: trade name "Noxeller DM-10", Ouchi Shinko Kagaku Co., Ltd.) 0.6 parts by mass and sulfur-based cross-linking accelerator B (tetramethylthiuram disulfide: trade name "Axel TS-10", Ouchi Shinko Kagaku Co., Ltd.) 2.2 parts by mass were used. , And 12 parts by mass of a heat-expandable foaming agent (microcapsule: trade name "Advancel (registered trademark) EM304", manufactured by Sekisui Chemical Co., Ltd.) instead of the thermally decomposable foaming agent. A rubber metal laminate was prepared in the same manner as in the above, and foaming characteristics evaluation, heat resistance evaluation and corrosiveness evaluation were carried out. The evaluation results are shown in Table 1 below.

(Comparative Example 2)
Instead of the sulfur-based cross-linking agent, 8 parts by mass of a quinoid-based cross-linking agent (p-quinone dioxime: trade name "Barnock GM-P", manufactured by Ouchi Shinko Kagaku Co., Ltd.) was used, and the cross-linking accelerators A and B A rubber metal laminate was prepared in the same manner as in Comparative Example 1 except that 3 parts by mass of a cross-linking aid (m-phenylenedi maleimide trade name "Barnock PM", manufactured by Ouchi Shinko Kagaku Co., Ltd.) was used instead. , Foaming characteristics evaluation, heat resistance evaluation and corrosiveness evaluation were carried out. The evaluation results are shown in Table 1 below.

(Comparative Example 3)
Except for the fact that 2 parts by mass of a peroxide-based cross-linking agent (dicumyl peroxide: trade name "Park Mill D", manufactured by Nichiyu Co., Ltd.) was used instead of the sulfur-based cross-linking agent, and no cross-linking aid was used. , A rubber metal laminate was prepared in the same manner as in Comparative Example 2, and foaming property evaluation, heat resistance evaluation and corrosiveness evaluation were carried out. The evaluation results are shown in Table 1 below.

The blending amount of each component in Table 1 above is as follows.
Ethylene acrylate rubber: Brand name "VAMAC GLS" (manufactured by DuPont)
Nitrile rubber: High nitrile rubber (bonded acrylonitrile content 41.5%): Product name "JSR N220S" (manufactured by JSR)
Carbon Black A: Medium-grain pyrolysis (MT: Medium Thermal) Carbon Black: Product name "THERMAX N990 LSR," (manufactured by Cancurve)
Carbon Black B: Medium Reinforcement (SRF: Semi-Reinforcing Furnace) Carbon Black: Product Name "HTC # SS" (manufactured by Nittetsu Carbon Co., Ltd.)
Amine-based cross-linking agent: Hexamethylenediamine carbamate: Trade name "Cheminox AC6-66" (manufactured by Unimatec)
Amine-based cross-linking accelerator: Amination derivative (tertiary amine complex adsorbed on an amorphous silica carrier): Trade name "Vulcofac ACT-55" (manufactured by DuPont)
Sulfur-based cross-linking agent: Colloidal sulfur A (manufactured by Tsurumi Chemical Co., Ltd.)
Sulfur-based cross-linking accelerator A: Dibenzothiazil disulfide: Trade name "Noxeller DM-10" (manufactured by Ouchi Shinko Kagaku Co., Ltd.)
Sulfur-based cross-linking accelerator B: Tetramethylthiuram disulfide: Trade name "Axel TS-10" (manufactured by Ouchi Shinko Kagaku Co., Ltd.)
Quinone-based cross-linking agent: p-quinone dioxime: trade name "Barnock GM-P" (manufactured by Ouchi Shinko Kagaku Co., Ltd.)
Crosslinking aid: m-phenylenedimaleimide: Brand name "Barnock PM" (manufactured by Ouchi Shinko Kagaku Co., Ltd.)
Peroxide cross-linking agent: Dikmyl peroxide: Brand name "Park Mill D" (manufactured by NOF CORPORATION)
Stearic acid: Brand name "DTST" (manufactured by Miyoshi Oil & Fat Co., Ltd.)
Anti-aging agent: 4,4'-bis (α, α-dimethylbenzyl) diphenylamine: Trade name "Nocrack CD" (manufactured by LANXESS)
Zinc oxide (manufactured by Shodo Chemical Co., Ltd.)
Plasticizer: Non-phthalate plasticizer: Brand name "Mezamol" (manufactured by LANXESS)
Pyrolytic foaming agent: Azodicarbonamide: Trade name "Vinihole AC # 3" (manufactured by Eiwa Kasei Co., Ltd.)
Thermal expansion foaming agent: Microcapsules: Product name "Advancel EM304" (manufactured by Sekisui Chemical Co., Ltd.)

As can be seen from Table 1, the rubber metal laminate in which the rubber layer contains ethylene acrylate rubber and an amine-based cross-linking agent not only provides a sufficient foaming ratio of the rubber layer, but also has heat resistance, corrosiveness and stickiness. (See Examples 1 to 7). Further, when Example 1 and Examples 2 to 7 are compared, stable foaming characteristics can be obtained regardless of whether a heat-expandable foaming agent or a thermally decomposable foaming agent is used as the foaming agent, which is excellent. It can be seen that heat resistance, corrosiveness and stickiness can be obtained. Further, as can be seen from Examples 1 to 7, excellent heat resistance, corrosiveness and stickiness can be obtained even if the amount of the foaming agent, the amount of carbon black and the amount of the amine-based cross-linking agent are changed. It turns out that it can be obtained.

On the other hand, when nitrile rubber was crosslinked with a sulfur-based cross-linking agent, the brass plate was corroded in the corrosion and stickiness test, resulting in poor corrosiveness (see Comparative Example 1). It is considered that this result is because the brass plate was corroded by the sulfur component based on the sulfur-based cross-linking agent contained in the rubber layer. In addition, when nitrile rubber was crosslinked with a peroxide-based cross-linking agent, corrosion did not occur in the corrosion and stickiness test, but the rubber adhered to the steel plate and stainless steel plate, resulting in partial transfer, resulting in stickiness. The sex was poor (see Comparative Example 3). This result is considered to be because the peroxide-based cross-linking agent reacted with oxygen in the air and could not sufficiently cross-link in the air. Further, in Comparative Example 1 and Comparative Example 2, the change in pencil hardness before and after the heat resistance test was large, and the heat resistance was poor. It is considered that this result is because sufficient heat resistance could not be obtained because nitrile rubber was used. Further, when the nitrile rubber is crosslinked with a quinoid-based cross-linking agent, the corrosiveness and the stickiness are good, while the pencil hardness changes significantly before and after the heat resistance test as in Comparative Examples 1 and 3, and the heat resistance is high. The sex became poor (see Comparative Example 2).

From the above results, according to the above embodiment, by cross-linking the ethylene acrylate rubber with an amine-based cross-linking agent, not only a sufficient foaming ratio can be obtained, but also corrosiveness and stickiness are improved and excellent. It can be seen that a rubber composition capable of obtaining a rubber metal laminate having heat resistance, a rubber metal laminate using the rubber composition, and a gasket provided with the rubber metal laminate can be realized.

As described above, according to the above embodiment, the rubber composition, the rubber metal laminate, the gasket and the rubber metal can prevent metal corrosion due to the sulfur component and can obtain a gasket having excellent heat resistance. It has the effect of realizing a method for manufacturing a laminate, and is particularly used for gaskets such as inverter cases for electric vehicles (EV: Electric Metal) and hybrid electric vehicles (HEV: Hybrid Electric Metal) and gaskets such as heat-resistant gaskets. be able to.

Although one embodiment of the present invention has been described above, the embodiment of the present invention is not limited by the content of the present embodiment. In addition, the above-mentioned components include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those having a so-called equal range. Furthermore, the components described above can be combined as appropriate. Further, various omissions, replacements or changes of the components can be made without departing from the gist of the above-described embodiment.

Claims (8)

1. With 100 parts by mass of ethylene acrylate rubber
   Carbon black 1 part by mass or more and 200 parts by mass or less,
   Amine-based cross-linking agent 0.1 parts by mass or more and 20 parts by mass or less,
   1 part by mass or more and 50 parts by mass or less of the foaming agent
   A rubber composition comprising.
2. The rubber composition according to claim 1, wherein the amine-based cross-linking agent contains diamines.
3. The rubber composition according to claim 1 or 2, wherein the foaming agent contains at least one selected from the group consisting of a thermal expansion type foaming agent and a thermal decomposition type foaming agent.
4. With metal parts
   A foamed rubber layer provided on the metal member and crosslinked with the rubber composition according to any one of claims 1 to 3.
   A rubber-metal laminate characterized by being equipped with.
5. The rubber metal laminate according to claim 4, wherein the brass plate, the steel plate, and the stainless steel plate are not corroded in the corrosion and stickiness test according to JIS B2403 9.2.
6. The fourth or fifth aspect, wherein the change in the hardness of the pencil hardness of the foam rubber layer in the scratch hardness test based on JIS K5600-5-4 before and after heat aging at 150 ° C. for 24 hours is 3 points or less. Rubber metal laminate.
7. A gasket comprising the rubber metal laminate according to any one of claims 4 to 6.
8. A rubber composition obtained by mixing 100 parts by mass of ethylene acrylate rubber, 1 part by mass or more and 200 parts by mass or less of carbon black, 0.1 parts by mass or more and 20 parts by mass or less of an amine-based cross-linking agent, and 1 part by mass or more and 50 parts by mass or less of a foaming agent The rubber composition preparation process to obtain the product and
   A cross-linking step of applying the rubber composition onto a metal member and cross-linking by oven cross-linking to obtain a rubber metal laminate.
   A method for producing a rubber metal laminate, which comprises.

Images