Rubber-metal laminate and gasket

Abstract

The present application provides a rubber-metal laminate and a gasket. The rubber-metal laminate of the present application includes a metal member and a rubber layer provided on the metal member, the rubber layer having a 100% modulus value based on JIS K6251 of 6.0 MPa or more, and a thickness of less than 80 μm, the rubber layer containing nitrile rubber and carbon black, the carbon black being MT carbon black, the carbon black being compounded in an amount of 151 parts by mass or more with respect to 100 parts by mass of rubber component. In addition, the gasket of the present application is characterized by including the above rubber-metal laminate. According to the present application, a rubber-metal laminate and a gasket which can prevent overflow of a rubber layer when a compressive stress is applied and which have excellent sealing properties for a sealing target member can be achieved.

Description

[0001] This application is a divisional application of patent application No. 202180021996.2 (International Application No. PCT / JP2021 / 009584), filed on March 10, 2021, entitled "Rubber-Metal Laminate and Gasket". Technical Field

[0002] This invention relates to rubber-metal laminates and gaskets, and more specifically, to rubber-metal laminates and gaskets having a rubber layer disposed on a metal component. Background Technology

[0003] Conventionally, a metal gasket has been proposed for sealing between two components of an internal combustion engine, such as the cylinder head and the cylinder block (for example, see Patent Document 1). This metal gasket includes a rubber-metal laminate comprising a metal substrate and rubber layers disposed on two main surfaces of the metal substrate. In the metal gasket described in Patent Document 1, the portion between the cylinder head and the cylinder block, which is the component to be sealed, is sealed by fastening the rubber-metal laminate between the cylinder head and the cylinder block.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-130224 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, in the metal gasket described in Patent Document 1, since the rubber-metal laminate is fastened between metal components such as the cylinder head and cylinder block, strong compressive stress is applied to the rubber-metal laminate during use. In such a rubber-metal laminate, the rubber layer deforms due to the applied compressive stress during use, causing rubber to overflow from the rubber-metal laminate, thus failing to achieve the desired function.

[0009] To improve spillage caused by deformation of the rubber layer, it is effective to incorporate fillers such as carbon black and silica into the rubber layer to increase its hardness. However, there are also cases where the sealing performance of the sealing component decreases as the hardness of the rubber layer increases. Furthermore, to improve rubber spillage, studies have been conducted on increasing the amount of sulfur used as a crosslinking agent in the rubber layer composition to increase the crosslinking density of the rubber layer. However, even increasing the crosslinking density of the rubber layer did not predict a significant improvement in rubber spillage. As mentioned above, in existing rubber-metal laminates, in practice, simply increasing hardness sometimes fails to adequately improve rubber spillage, and no relationship has been found between the physical properties of the rubber and spillage.

[0010] The present invention was made in view of the actual situation, and its object is to provide a rubber-metal laminate and gasket that can prevent the rubber layer from overflowing when compressive stress is applied and has excellent sealing performance for the sealed component.

[0011] Technical means for solving technical problems

[0012] The rubber-metal laminate of the present invention is characterized in that it includes a metal component and a rubber layer disposed on the metal component, wherein the 100% modulus value of the rubber layer based on JIS K6251 is 6.0 MPa or more, and the thickness of the rubber layer is less than 80 μm.

[0013] According to the rubber-metal laminate of the present invention, since the 100% modulus of the rubber layer is 6.0 MPa or more and the thickness of the rubber layer is less than 80 μm, the elastic modulus of the rubber layer is moderately increased. Therefore, compared with cases where the hardness of the rubber layer is increased by using filler materials, the rubber-metal laminate can prevent the deterioration of processability and sealing properties during the mixing of the rubber composition of the rubber layer, and can ensure the required elastic modulus of the rubber layer. As a result, even when compressive stress is applied to the rubber-metal laminate, it is possible to further prevent the rubber layer from overflowing from the rubber-metal laminate, thus achieving a rubber-metal laminate with excellent sealing performance for the sealed component.

[0014] For the aforementioned rubber-metal laminate, it is preferable that the 100% modulus value of the rubber layer based on JIS K6251 is 6.0 MPa or higher. According to this structure, the rubber-metal laminate can prevent deterioration of processability and sealing properties during mixing, and can sufficiently ensure the required elastic modulus of the rubber layer. As a result, even when compressive stress is applied to the rubber-metal laminate, it can further prevent the rubber layer from overflowing from the rubber-metal laminate, thus further improving the sealing performance of the sealed component.

[0015] For the aforementioned rubber-metal laminate, it is preferable that the elongation value of the rubber layer based on JIS K6251 is 100% or more. According to this structure, because the elongation value of the rubber layer is within an appropriate range, even under compressive stress, it is possible to further prevent the rubber layer from overflowing from the rubber-metal laminate, and further improve the sealing performance of the sealed component.

[0016] For the aforementioned rubber-metal laminate, the thickness of the rubber layer is preferably 25 μm or more. According to this structure, the relationship between the 100% modulus value of the rubber layer and its thickness is within an appropriate range, further improving the elastic modulus of the rubber layer. As a result, even under compressive stress, the rubber-metal laminate can further prevent the rubber layer from overflowing from the laminate, further improving the sealing performance of the sealed component.

[0017] For the aforementioned rubber-metal laminate, it is preferable that the rubber layer contains carbon black at a concentration of 28% by mass or more relative to the total mass of the rubber layer. According to this structure, the rubber-metal laminate can prevent deterioration of the seal and ensure the required elastic modulus of the rubber layer. As a result, even under compressive stress, the rubber-metal laminate can further prevent the rubber layer from overflowing from the laminate and further improve the sealing performance of the sealed component.

[0018] For the aforementioned rubber-metal laminate, it is preferable that the metal plate and the rubber layer are bonded using at least one adhesive selected from the group consisting of phenolic resin and epoxy resin. According to this structure, since the adhesion between the metal plate and the rubber layer is improved, it is possible to further prevent the rubber layer from overflowing from the rubber-metal laminate and further improve the sealing performance of the sealed component.

[0019] For the aforementioned rubber-metal laminate, it is preferable that the rubber layer contains nitrile rubber. According to this structure, since the nitrile rubber contained in the rubber layer has appropriate elasticity, even under compressive stress acting on the rubber-metal laminate, it is possible to further prevent the rubber layer from overflowing from the rubber-metal laminate and further improve the sealing performance of the sealed component.

[0020] The gasket of the present invention is characterized by comprising the above-described rubber-metal laminate.

[0021] According to the gasket of the present invention, since the 100% modulus of the rubber layer is 6.0 MPa or more and the thickness of the rubber layer is less than 80 μm, the elastic modulus of the rubber layer is moderately increased. Therefore, compared to cases where the hardness of the rubber layer in a rubber-metal laminate is increased by using filler materials, the gasket can prevent deterioration of the processability and sealing properties of the rubber composition during mixing, and can ensure the required elastic modulus of the rubber layer. As a result, even when compressive stress is applied to the gasket, the rubber layer can be prevented from overflowing from the rubber-metal laminate, thus achieving a gasket with excellent sealing performance for the sealed component.

[0022] Invention Effects

[0023] According to the present invention, a rubber-metal laminate and gasket that can prevent the rubber layer from overflowing when compressive stress is applied and has excellent sealing performance for the sealed object component can be realized. Detailed Implementation

[0024] The embodiments of the present invention will now be described in detail.

[0025] The rubber-metal laminate of this invention is suitable for use as a sealing member such as a gasket. The metal laminate of this embodiment includes a metal member and a rubber layer disposed on at least one main surface of the metal member. The 100% modulus of the rubber layer is 6.0 MPa or more, and the thickness of the rubber layer is less than 80 μm. Hereinafter, various structural elements of the rubber-metal laminate of this embodiment will be described in detail.

[0026] (Metal components)

[0027] For metal components, metal sheets such as iron, stainless steel, aluminum, magnesium, galvanized steel, and copper can be used. For iron, cold-rolled steel sheets (SPCC: Steel Plate Cold Commercial), high-tensile steel sheets, and mild steel sheets can be used. For stainless steel, ferritic, martensitic, and austenitic stainless steel sheets can be used. Specific examples of stainless steel include SUS304, SUS301, SUS301H, and SUS430. For aluminum, aluminum sheets and die-cast aluminum sheets can be used.

[0028] Metal components are preferably used after their surfaces have been degreased through alkaline degreasing treatment or similar processes. Additionally, metal components can be roughened using methods such as shot blasting, Scotch-Brite (registered trademark), hair-line finishing, and dull finish, as needed.

[0029] For metal components, it is preferable that the bonding surface with the adhesive has undergone a substrate treatment (surface treatment). There are no particular limitations on the substrate treatment; known substrate treatments can be used. When using ferrous materials such as cold-rolled steel sheets and high-tensile steel sheets, and stainless steel as metal components, it is preferable to use chemical conversion treatment methods with various chemical conversion agents, or various plating methods such as electroplating and hot-dip galvanizing using metals such as zinc. Examples of chemical conversion agents for metal components include, for example, phosphate-based agents such as zinc phosphate and iron phosphate, and coating-type chromate agents. From an environmental perspective, chromium-free chemical conversion agents that are substantially chromium-free are preferred.

[0030] For substrate treatment of metal components using chemical conversion agents, the chemical conversion agent is applied to the metal component using known liquid-wetting methods such as spraying, dipping, brushing, and roller coating. In the case of reactive chemical conversion agents, it is necessary to ensure the required reaction time and temperature.

[0031] The thickness of the metal component is appropriately set according to the application of the rubber-metal laminate. When the rubber-metal laminate is used for sealing components such as gaskets, the thickness of the metal component is preferably 100 μm or more and 2000 μm or less, more preferably 150 μm or more and 1000 μm or less, and even more preferably 200 μm or more and 500 μm or less.

[0032] In addition to substrate treatment, a primer coating is preferably formed on the metal component of the rubber-metal laminate, or a primer coating is formed on the metal component instead of substrate treatment. By performing substrate treatment or forming a primer coating, the adhesion between the rubber layer and the metal component in the rubber-metal laminate can be improved, and the heat resistance and water resistance of the rubber-metal laminate can be significantly improved. In addition, by performing substrate treatment or forming a primer coating, the rubber-metal laminate can be suitable for use as a laminated composite metal, i.e., a gasket, formed by laminating the rubber-metal laminate with other metal plates.

[0033] The primer coating can be formulated using inorganic compounds such as silicon compounds, compounds of metals such as titanium, zirconium, vanadium, aluminum, molybdenum, tungsten, manganese, zinc, and cerium, and their oxides, as well as organic compounds such as silicone resins, phenolic resins, epoxy resins, and polyurethanes. The primer coating can be formulated using commercially available primer solutions, or it can be formulated using primer solutions based on various known technologies.

[0034] The primer coating is applied using a primer solution, which is obtained by dissolving or dispersing raw materials containing the aforementioned inorganic and organic compounds in an organic solvent or an aqueous solvent. Examples of usable organic solvents include alcohols such as methanol, ethanol, and isopropanol, and ketones such as acetone and methyl ethyl ketone. The primer solution can also be formulated as an aqueous solution using an aqueous solvent, provided it maintains liquid stability.

[0035] The obtained primer solution is applied to a metal plate using methods such as spraying, dipping, brushing, and roller coating. Furthermore, the primer coating is formed by drying the primer solution applied to the metal plate at room temperature or with hot air, or by sintering.

[0036] (Adhesive)

[0037] Adhesives bond the rubber layer to the metal component. Commonly available adhesives such as phenolic resins, epoxy resins, polyurethane resins, and silanes are used as adhesives. These adhesives can be appropriately selected depending on the application of the rubber-metal laminate.

[0038] In a rubber-metal laminate, the metal plate and the rubber layer are preferably bonded by at least one adhesive selected from the group consisting of phenolic resin and epoxy resin. As a result, the improved adhesion between the metal plate and the rubber layer further prevents the rubber layer from overflowing from the rubber-metal laminate under compressive stress, and further improves the sealing performance of the sealed component.

[0039] For example, phenolic varnish-type (novolac) phenolic resin and resol-type phenolic resin can be used as phenolic resins. One type of phenolic varnish-type phenolic resin or resol-type phenolic resin can be used alone, or two or more types can be used in combination. Furthermore, as an adhesive, an adhesive containing both phenolic varnish-type and resol-type phenolic resins and uncured nitrile rubber can also be used.

[0040] As a phenolic varnish-type phenolic resin, a product obtained by condensing phenols and formaldehyde in the presence of an acid catalyst can be used. Examples of phenols include phenol, p-cresol, m-cresol, p-tert-butylphenol, p-phenylphenol, bisphenol A, etc., which have two or three substituted hydrogen atoms at at least one of the ortho and para positions relative to the phenolic hydroxyl group. These phenolic resins can be used individually or in combination of two or more. Examples of acid catalysts include oxalic acid, hydrochloric acid, and maleic acid. From the viewpoint of improving the adhesion between the metal sheet and the rubber layer, a phenolic varnish-type phenolic resin with a melting point of 80°C or higher and 150°C or lower is preferred, and a phenolic varnish-type phenolic resin with a melting point of 120°C or higher obtained by using m-cresol and formaldehyde is more preferred.

[0041] As a primary phenolic resin, the product obtained by condensing phenols and formaldehyde in the presence of an alkaline catalyst can be used. Examples of phenols include phenol, p-cresol, m-cresol, and phenols such as p-tert-butylphenol, p-phenylphenol, and bisphenol A, which have two or three substituted hydrogen atoms at at least one of the ortho and para positions relative to the phenolic hydroxyl group. These phenolic resins can be used individually or in combination of two or more. Examples of alkaline catalysts include, for example, alkali metal hydroxides such as ammonia and sodium hydroxide, magnesium hydroxide, and sodium carbonate.

[0042] Examples of epoxy resins include bisphenol A type, cresol phenolic varnish type, biphenyl type, and brominated epoxy resins. These epoxy resins can be used individually or in combination of two or more. Among these resins, bisphenol A type epoxy resin and cresol phenolic varnish type epoxy resin are preferred from the perspectives of readily available commercial products and excellent heat resistance. For example, commercially available products manufactured by DIC Corporation under the trade names "EPICLON 860", "EPICLON 1055", "EPICLON 2050", "EPICLON 3050", "EPICLON 4050", "EPICLON 7050", and "EPICLON HM-091" can be used. In addition, as commercially available products of cresol varnish type epoxy resin, for example, commercially available products manufactured by DIC Corporation under trade names such as "EPICLON N-660", "EPICLON N-670", "EPICLON N-680", and "EPICLON N-690" can be used.

[0043] The aforementioned adhesives are used in the form of solutions dissolved in organic solvents. Examples of organic solvents include ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatic hydrocarbons such as toluene and xylene. These organic solvents can be used individually or in combination of two or more.

[0044] For adhesives, for example, relative to 100 parts by weight of phenolic resin of the varnish type, it is preferable to combine phenolic resin of the first-order phenolic resin type in a proportion of 10 parts by weight or more and 1000 parts by weight or less, and more preferably in a proportion of 60 parts by weight or more and 400 parts by weight or less. By making the phenolic resin of the first-order phenolic resin type 1000 parts by weight or less relative to 100 parts by weight of the phenolic resin of the varnish type, it is possible to prevent a decrease in the adhesiveness of the rubber layer. In addition, by making the phenolic resin of the first-order phenolic resin type 10 parts by weight or more, it is possible to prevent a decrease in the adhesion to the surface of the metal component.

[0045] From the viewpoint of improving the adhesion between the metal component and the rubber layer, the adhesive is preferably applied to a metal plate with a primer coating. Furthermore, the adhesive layer can be a single layer or multiple layers. Alternatively, after forming a phenolic adhesive layer containing an organometallic compound on the primer coating applied to the metal component, a further phenolic adhesive layer can be applied on top of that primer layer, thus creating a multi-segment structure for the adhesive. This multi-segment structure of the adhesive layer enhances the adhesion between the primer coating and the rubber layer.

[0046] For the adhesive, ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, or mixtures thereof, can be used to prepare an adhesive solution with a solid component concentration of 1% by mass or more and 10% by mass or less. After the adhesive solution is applied to the metal component, it is dried and sintered at a temperature of 100°C or higher and 250°C or lower for 1 minute or more and approximately 30 minutes to form an adhesive layer. The preferred application amount of the adhesive after drying and sintering is 50 mg / m³. 2 Above and 2000 mg / m 2 The following range applies. Furthermore, the adhesive is preferably applied in such a way that the thickness of the dried adhesive layer is 0.5 μm or more and 5 μm or less.

[0047] (Rubber layer)

[0048] In the rubber-metal laminate of this embodiment, the 100% modulus value of the rubber layer based on JIS K6251 is 6.0 MPa or more. Therefore, even when high compressive stress is applied to the rubber-metal laminate, the rubber layer maintains an appropriate modulus of elasticity, which can suppress the overflow of the rubber layer from the rubber-metal laminate, thus improving the sealing performance of the sealed component. Furthermore, since the rubber-metal laminate has an appropriate modulus of elasticity without increasing the hardness of the rubber layer, it prevents deterioration of processability and sealing performance during mixing, maintains the softness of the rubber, and further improves the sealing performance of the sealed component. From the viewpoint of further improving the above effects, the 100% modulus value of the rubber layer is more preferably 8.0 MPa or more, more preferably 10 MPa, and even more preferably 30 MPa or less, more preferably 25 MPa or less, and even more preferably 20 MPa or less.

[0049] Furthermore, in the rubber-metal laminate of this embodiment, the elongation value of the rubber layer based on JIS K6251 is preferably 100% or more. Therefore, since the elongation value of the rubber layer is within an appropriate range, even when compressive stress is applied to the rubber-metal laminate, it is possible to further prevent the rubber layer from overflowing from the rubber-metal laminate and further improve the sealing performance of the sealing component. Moreover, from the viewpoint of further improving the above-mentioned effects, the elongation value of the rubber layer is more preferably 140% or more, more preferably 170% or more, and preferably 300% or less, more preferably 275% or less, and even more preferably 250% or less.

[0050] Furthermore, in the rubber-metal laminate of this embodiment, from the viewpoint of obtaining an appropriate elastic modulus without excessively increasing the hardness of the rubber layer, preventing the deterioration of processability and sealing properties during mixing, and improving the sealing performance of the sealing target component, the hardness of the rubber layer based on JIS K6253 is preferably 65 or more and 100 or less, more preferably 70 or more and 95 or less, and even more preferably 80 or more and 90 or less.

[0051] Furthermore, in the rubber-metal laminate of this embodiment, from the viewpoint of preventing the rubber layer from overflowing when compressive stress is applied and improving the sealing performance of the sealing object component, the tensile strength measured based on JIS K6251 is preferably 7.5 MPa or more and 30 MPa or less, more preferably 10 MPa or more and 27.5 MPa or less, and even more preferably 12 MPa or more and 25 MPa or less.

[0052] For the rubber layer, various rubber materials can be used within the scope of achieving the effects of the present invention. Examples of rubber materials include, for instance, nitrile butadiene rubber (NBR), an acrylonitrile-butadiene copolymer; hydrogenated nitrile butadiene rubber (HNBR), which hydrogenates the unsaturated bond portion of nitrile butadiene rubber; and fluororubber. From the viewpoint of improving sealing performance by preventing the rubber layer from overflowing from the rubber-metal laminate, nitrile butadiene rubber and hydrogenated nitrile butadiene rubber are preferred, and nitrile butadiene rubber is more preferred. Furthermore, when used as a rubber layer in applications such as cylinder head gaskets for motor vehicles, it is preferable to include at least one material selected from the group consisting of fluororubber and nitrile butadiene rubber, and preferably nitrile butadiene rubber. Additionally, by crosslinking the rubber layer, superior heat resistance and adhesion can be obtained.

[0053] As for nitrile rubber, from the viewpoints of improving the adhesion between the rubber layer and the adhesive and improving cold resistance, a bound acrylonitrile content of 18% or more and 48% or less is preferred, a bound acrylonitrile content of 31% or more and 42% or less is more preferred, and a medium-high bound acrylonitrile content of 31% or more and less than 36% is even more preferred. Furthermore, as for nitrile rubber, from the viewpoints of improving abrasion / wear resistance and improving compounding processability, a Mooney viscosity (ML) is preferred. 1+4 Acrylonitrile rubber with a viscosity of 30 or higher and 85 or lower at 100°C can be used, as well as acrylonitrile-butadiene copolymer rubber with a Mooney viscosity of ML 1+4 (100°C) of 40 or higher and 70 or lower. Alternatively, commercially available products such as "Nipol (registered trademark) DN3350" (manufactured by Zeon Corporation of Japan) can be used as nitrile rubber.

[0054] Furthermore, from the viewpoint of improving the hardness of the rubber layer and preventing the rubber layer from overflowing from the rubber-metal laminate when compressive stress is applied, the rubber layer preferably contains a composition containing carbon black.

[0055] Examples of carbon blacks include hard carbon blacks such as Super Abrasion Furnace (SAF), Intermediate Super Abrasion Furnace (ISAF), High Abrasion Furnace (HAF), and Easy Processing Channel (EPC); and soft carbon blacks such as eXtra Conductive Furnace (XCF), Fast Extruding Furnace (FEF), General Purpose Furnace (GPF), High Modulus Furnace (HMF), Semi-Reinforcing Furnace (SRF), Fine Thermal (FT), and Medium Thermal (MT). These carbon blacks can be used individually or in combination of two or more types. Among these, soft carbon black is preferred, and among soft carbon black, medium-strength carbon black and medium-grain pyrolysis carbon black are more preferred. Commercially available medium-grain pyrolysis carbon black such as "THERMAX (registered trademark) N990 LSR" (manufactured by Cancarb) can be used, as can commercially available medium-strength carbon black such as "HTC#SS" (manufactured by Nippon SteelCarbon Co., Ltd.) and "ASAHI#50HG" (manufactured by Asahi Carbon Co., Ltd.).

[0056] From the viewpoint of improving sealing performance by preventing the rubber layer from overflowing from the rubber-metal laminate when compressive stress is applied, the amount of carbon black used is preferably 50 parts by mass or more and 300 parts by mass or less, more preferably 70 parts by mass or more and 250 parts by mass or less, and even more preferably 85 parts by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the rubber component.

[0057] From the viewpoint of improving sealing performance by preventing the rubber layer from overflowing from the rubber-metal laminate when compressive stress is applied, the amount of carbon black incorporated is preferably 28% by mass or more and 80% by mass or less relative to the total mass of the rubber composition, more preferably 30% by mass or more and 70% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less.

[0058] Furthermore, when the carbon black is MT carbon black, from the viewpoint of preventing the rubber layer from overflowing from the rubber-metal laminate when compressive stress is applied, thereby improving the sealing performance, the amount of carbon black in the formulation is preferably 50 parts by mass or more and 250 parts by mass or less relative to 100 parts by mass of rubber component, more preferably 70 parts by mass or more and 200 parts by mass or less, and even more preferably 85 parts by mass or more and 175 parts by mass or less.

[0059] When the carbon black is MT carbon black, from the viewpoint of preventing the rubber layer from overflowing from the rubber-metal laminate when compressive stress is applied to improve sealing, the amount of carbon black incorporated relative to the total mass of the rubber composition is preferably 28% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less.

[0060] Furthermore, when the carbon black is SRF carbon black, from the viewpoint of preventing the rubber layer from overflowing from the rubber-metal laminate when compressive stress is applied to improve sealing, the amount of carbon black is preferably 35 parts by mass or more and 200 parts by mass or less relative to 100 parts by mass of rubber component, more preferably 45 parts by mass or more and 150 parts by mass or less, and even more preferably 50 parts by mass or more and 125 parts by mass or less.

[0061] When the carbon black is SRF carbon black, from the viewpoint of preventing the rubber layer from overflowing from the rubber-metal laminate when compressive stress is applied to improve sealing, the amount of carbon black incorporated relative to the total mass of the rubber composition is preferably 25% by mass or more and 70% by mass or less, more preferably 27.5% by mass or more and 60% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less.

[0062] The rubber composition is cross-linked by applying it to a metal component or primer coating. The rubber composition preferably contains a vulcanizing agent and a vulcanization accelerator. For example, commercially available products such as colloidal sulfur A (manufactured by Tsurumi Chemical Industry Co., Ltd.) and the trade name "VULNOC (registered trademark) R" (4,4'-dithiodimorpholine: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) can be used. The amount of vulcanizing agent is, for example, 0.1 parts by weight or more and 10 parts by weight or less per 100 parts by weight of the rubber component.

[0063] As vulcanization accelerators, various sulfur-containing vulcanization accelerators can be used, including guanidine-based, aldehyde-amine-based, aldehyde-amine-based, thiazole-based, sulfinamide-based, thiourea-based, thiuram-based, dithiocarbamate-based, and xanthate-based accelerators. Among these, tetramethylthiuram disulfide, tetrabenzylthiuram disulfide, and N-cyclohexyl-2-benzothiazolyl sulfinamide are preferred as sulfur-containing vulcanization accelerators. Additionally, commercially available products under the trade names "NOCCELER (registered trademark) TBZTD" (tetrabenzylthiuram disulfide: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), "NOCCELER (registered trademark) CZ-P" (N-cyclohexyl-2-benzothiazolyl sulfinamide: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), and "NOCCELER (registered trademark) TT-P" (tetramethylthiuram disulfide: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) can also be used. The amount of vulcanization accelerator is, for example, more than 1 part by mass and less than 20 parts by mass relative to 100 parts by mass of rubber component.

[0064] In addition, the rubber composition may also include fillers such as calcium carbonate and silica, as needed. Various types of calcium carbonate, such as heavy calcium carbonate and synthetic calcium carbonate, can be used as calcium carbonate. Alternatively, commercially available products under the trade name "WHITON SB-Aka" (heavy calcium carbonate, manufactured by Bikawa Powder Chemical Industry Co., Ltd.) can also be used. The amount of calcium carbonate in the composition is preferably 10 parts by weight or more and 100 parts by weight or less relative to 100 parts by weight of the rubber component.

[0065] Various types of silica can be used as the silica to achieve the effects of this invention. For example, amorphous silica such as dry-process silica and wet-process silica can be used. The dry-process silica is manufactured by thermal decomposition of halogenated silica or organosilicon compounds, or by air oxidation of silica (SiO) obtained by heating and reducing silica sand to vaporize. The wet-process silica is manufactured by thermal decomposition of sodium silicate, etc. Alternatively, commercially available silica such as "Nipsil E-74P" (manufactured by Tosoh silica Co., Ltd.) can also be used. The preferred amount of silica is, for example, 5 parts by weight or more and 50 parts by weight or less relative to 100 parts by weight of the rubber component.

[0066] The rubber composition may also contain plasticizers, acid-resistant agents such as zinc oxide, stearic acid, anti-aging agents, and waxes, which are commonly used in the rubber industry, as required. For example, a commercially available product under the trade name "ADK CIZER (registered trademark) RS107" (manufactured by ADEKA Co., Ltd.) is an example of a plasticizer. The amount of plasticizer incorporated relative to 100 parts by weight of the rubber component is, for example, 1 part by weight or more and 50 parts by weight or less.

[0067] As an acid acceptor, commercially available products such as zinc oxide (manufactured by Seido Chemical Industry Co., Ltd.) can be used, for example. As stearic acid, commercially available products such as "DTST" (manufactured by Miyoshi Oils Co., Ltd.) can be used, for example. Furthermore, as an anti-aging agent, commercially available products such as "NOCRAC (registered trademark) 810-NA" (2,2,4-trimethyl-1,2-dihydroquinoline polymer: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) can be used, for example. Furthermore, as a wax, commercially available products such as "SUNTIGH (registered trademark) R" (microcrystalline wax: manufactured by Seiko Chemical Co., Ltd.) can be used, for example.

[0068] Furthermore, in the rubber-metal laminate of this embodiment, the thickness of the rubber layer is less than 80 μm. Therefore, the relationship between the 100% modulus value of the rubber layer and its thickness is within an appropriate range, thus preventing the rubber layer from overflowing from the rubber-metal laminate even under compressive stress, and further improving the sealing performance of the sealed component. Moreover, from the viewpoint of further improving the above-mentioned effects, the thickness of the rubber layer is preferably 30 μm or more, more preferably 40 μm or more and 75 μm or less, and even more preferably 45 μm or more and 70 μm or less.

[0069] <Method for manufacturing rubber-metal laminates>

[0070] The rubber-metal laminate of the above embodiment is manufactured using a metal component such as a stainless steel plate and the following rubber composition. This rubber composition is formed by combining rubber components and carbon black, and, as needed, adding a vulcanizing agent, vulcanization accelerator, calcium carbonate, silica, plasticizer, and various additives, and then mixing them using a mixer, kneader, Banbury mixer, or other mixing mill or open roller mixer. The rubber-metal laminate is manufactured by coating the rubber composition onto a surface-treated metal component through an adhesive layer, and then, for example, vulcanizing the rubber composition at a temperature of 160°C to 250°C for 0.5 minutes to 30 minutes to form a rubber layer. Preferably, the rubber composition is coated such that the thickness of the coated rubber layer is 50 μm to 200 μm. It should be noted that, from the viewpoint of preventing rubber adhesion, a resin-based or graphite-based coating agent may also be applied to the rubber layer of the rubber-metal laminate.

[0071] There are no particular restrictions on the coating method for applying the rubber composition to the metal component, as long as the rubber composition can be applied to the metal component. Examples of coating methods for the rubber composition include spraying, dipping, roller coating, and dispensing.

[0072] When manufacturing rubber compositions and when coating rubber compositions onto metal components, organic solvents can be added to the rubber compositions as needed to adjust the viscosity. There are no particular limitations on the organic solvents used, as long as they can adjust the viscosity of the rubber composition to the desired level. Examples of organic solvents include methyl ethyl ketone, toluene, and ethyl acetate. These organic solvents can be used individually or in combination of two or more.

[0073] As explained above, according to the above embodiment, the 100% modulus of the rubber layer is 6.0 MPa or higher, and the thickness of the rubber layer is less than 80 μm, thus moderately increasing the elastic modulus of the rubber layer. Therefore, compared to cases where the hardness of the rubber layer is increased by using filler materials, the rubber-metal laminate can prevent deterioration of the processability and sealing properties of the rubber layer during rubber composition mixing, and can ensure the required elastic modulus of the rubber layer. As a result, even when compressive stress is applied to the rubber-metal laminate, overflow of the rubber layer from the rubber-metal laminate can be further prevented, thus achieving a rubber-metal laminate with excellent sealing performance for the sealed component. Furthermore, in rubber-metal laminates, overflow has historically been improved by simply increasing the hardness of the rubber; however, by focusing on the 100% modulus value, overflow can be ensured even at low hardness, and improved sealing performance can be expected. Moreover, even without actually manufacturing a rubber-metal laminate, the overflow of the rubber layer under compressive stress can be predicted using the 100% modulus value, thus facilitating the evaluation of process reductions.

[0074] Furthermore, according to the above embodiment, a gasket comprising a rubber-metal laminate can be obtained. As a result, since the 100% modulus of the rubber layer is 6.0 MPa or more and the thickness of the rubber layer is less than 80 μm, the elastic modulus of the rubber layer is moderately increased. Therefore, compared to cases where the hardness of the rubber layer is increased by using filler materials, the gasket can prevent deterioration of the processability and sealing properties during the mixing of the rubber composition of the rubber layer, and can ensure the required elastic modulus of the rubber layer. Consequently, even when compressive stress is applied to the gasket, it is possible to further prevent the rubber layer from overflowing from the gasket, thus enabling the realization of a gasket with excellent sealing performance for the sealed component.

[0075] Example

[0076] The present invention will now be described in more detail based on embodiments provided to clarify the effects of the invention. It should be noted that the present invention is not limited to the following embodiments and comparative examples.

[0077] The inventors of this invention fabricated the rubber-metal laminate according to the above embodiments and evaluated the fabricated rubber-metal laminate by performing compression tests. The following describes the findings investigated by the inventors of this invention.

[0078] (Example 1)

[0079] <Evaluation of the thermoplasticity (TP) of rubber>

[0080] The following ingredients are added: 100 parts by weight of nitrile rubber (trade name "Nipol DN3350", manufactured by Ozen Co., Ltd., Japan); 90 parts by weight of carbon black A (medium-grain thermal decomposition (MT: Mdeium Thermal) carbon black: trade name "THERMAX N990LSR", manufactured by Cancarb Co., Ltd.); 5 parts by weight of zinc oxide (manufactured by Zhengtong Chemical Industry Co., Ltd.); 1 part by weight of stearic acid (trade name "DTST", manufactured by Miyoshi Oils Co., Ltd.); 2 parts by weight of anti-aging agent (2,2,4-trimethyl-1,2-dihydroquinoline polymer: trade name "NOCRAC 810-NA", manufactured by Ouchi Shinshin Chemical Industry Co., Ltd.); and microcrystalline wax (trade name "SUNTIGH"). A rubber composition was obtained by kneading with an open roller and mixing ingredients including 2 parts by weight of "R" (manufactured by Seiko Chemical Co., Ltd.), 1.5 parts by weight of vulcanizing agent A (colloidal sulfur A, manufactured by Tsurumi Chemical Industry Co., Ltd.), 1 part by weight of vulcanizing agent B (4,4'-dithiodimorpholine: trade name "VULNOC R", manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), 5 parts by weight of vulcanization accelerator A (tetrabenzylthiuram disulfide: trade name "NOCCELER TBZTD", manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), and 4 parts by weight of vulcanization accelerator B (N-cyclohexyl-2-benzothiazolyl sulfinamide: trade name "NOCCELER CZ-P", manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.). Next, the rubber composition was vulcanized at 170°C for 8 minutes to produce a rubber seal with a thickness of 2 mm. The hardness of the obtained rubber seal was determined based on JIS K6253, and the 100% modulus, tensile strength and elongation were determined based on JIS K6251.

[0081] <Preparation of Samples for Compression Test Evaluation>

[0082] On a 250 μm thick cold-rolled steel sheet (SPCC: SteelPlate Cold Commercia) treated with zinc phosphate, an adhesive was applied to a thickness of 3 μm and allowed to dry at room temperature. This adhesive was obtained by diluting 100 parts by weight of phenolic resin (trade name "SIXON 715A" 97% by weight, trade name "SIXON 715N" 3% by weight, both manufactured by ROHM AND HAAS) with an organic solvent of 440 parts by weight of methyl ethyl ketone and 110 parts by weight of methanol. Next, the formulated rubber composition used in the thermoplasticity evaluation was dissolved in an organic solvent and the viscosity was adjusted to 1000–10000 mPa·s. This solution was then applied to the cold-rolled steel sheet (coated with phenolic resin), and the cured rubber layer was 65 μm thick. The sheet was then vulcanized in an oven at 200°C for 3 minutes to produce a sample for compression testing of the rubber-laminated metal sheet. An anti-adhesion layer may also be applied here as needed. The samples prepared for compression testing were evaluated using the following evaluation method. The results are shown in Table 1 below.

[0083] <Compression Test Evaluation>

[0084] On the rubber layer of the sample used for compression testing of rubber-laminated metal sheets, a mold with a ring-shaped convex shape is pressed for 5 minutes at 150°C and 150 MPa. Then, the condition of the rubber layer is evaluated based on the following criteria.

[0085] 5 points: No metal was exposed, and the flow of rubber was barely confirmed.

[0086] 4 points: No metal is exposed, and the flow of rubber is minimal.

[0087] 3 points: A significant amount of rubber flow was produced, but it did not reach the point where the metal was exposed.

[0088] 2 points: The rubber has high fluidity, but little metal is exposed.

[0089] 1 point: The rubber flows a lot and the metal is exposed.

[0090] (Example 2)

[0091] Except that the amount of carbon black A was 151 parts by mass, samples for the compression test evaluation of rubber-laminated metal sheets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0092] (Example 3)

[0093] Except for using 65 parts by weight of carbon black B (SRF carbon black: trade name "HTC#SS", manufactured by Nippon Steel Carbon Co., Ltd.) instead of carbon black A, samples for evaluating the compression test of rubber laminated metal sheets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0094] (Example 4)

[0095] Except that the amount of carbon black B was 104 parts by mass, samples for the compression test evaluation of rubber-laminated metal sheets were prepared and evaluated in the same manner as in Example 3. The results are shown in Table 1 below.

[0096] (Example 5)

[0097] Except that the thickness of the rubber layer was 50 μm, samples for compression testing of the rubber-laminated metal sheet were prepared and evaluated in the same manner as in Example 4. The results are shown in Table 1 below.

[0098] (Example 6)

[0099] Except for using 56 parts by weight of carbon black C (semi-reinforcing furnace carbon black: trade name "ASAHI#50HG", manufactured by Asahi Carbon Co., Ltd.) instead of carbon black A, samples for evaluating the compression test of rubber laminated metal sheets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0100] (Example 7)

[0101] Except for using 90 parts by weight of carbon black C instead of carbon black A, samples for evaluating the compression test of rubber-laminated metal sheets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0102] (Example 8)

[0103] Except that the amount of carbon black A was 181 parts by weight and 10 parts by weight of plasticizer (trade name "ADK CIZERRS107", manufactured by ADEKA Co., Ltd.), samples for compression testing of rubber laminated metal sheets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0104] (Example 9)

[0105] Except that the amount of carbon black A was 40 parts by weight, carbon black B was 60 parts by weight, calcium carbonate (trade name "WHITON SB-Aka", manufactured by Bikawa Powdered Chemical Industry Co., Ltd.) was 60 parts by weight, silica (trade name "Nipsil E-74P", manufactured by Tosoh silica Co., Ltd.) was 30 parts by weight, and vulcanizing agent B was not used, samples for compression testing of rubber laminated metal sheets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0106] (Comparative Example 1)

[0107] Except that the amount of carbon black A was 45 parts by mass, samples for the compression test evaluation of rubber-laminated metal sheets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0108] (Comparative Example 2)

[0109] Except that the amount of carbon black B was 31 parts by mass, samples for the compression test evaluation of rubber-laminated metal sheets were prepared and evaluated in the same manner as in Example 3. The results are shown in Table 1 below.

[0110] (Comparative Example 3)

[0111] Except that the amount of carbon black C was set to 30 parts by mass, samples for the compression test evaluation of rubber-laminated metal sheets were prepared and evaluated in the same manner as in Example 6. The results are shown in Table 1 below.

[0112] (Comparative Example 4)

[0113] Except that the amount of carbon black A was 65 parts by weight, calcium carbonate (trade name "WHITON SB-Aka", manufactured by Bikawa Powder Chemical Industry Co., Ltd.) was 60 parts by weight, and silica (trade name "Nipsil E-74P", manufactured by Tosoh silica Co., Ltd.) was 5 parts by weight, samples for evaluating the compression test of rubber laminated metal sheets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0114] [Table 1]

[0115]

[0116] The details of each component in Table 1 above are as follows.

[0117] NBR: Nitrile butadiene rubber (medium-high nitrile butadiene rubber (acrylonitrile content ≥31% and <36%): trade name "Nipol DN3350", manufactured by OZEN Corporation, Japan)

[0118] Carbon Black A: Medium-grain thermal decomposition (MT) carbon black (trade name "THERMAX N990LSR", manufactured by Cancarb).

[0119] Carbon Black B: Semi-Reinforcing Furnace (SRF) Carbon Black (trade name "HTC#SS", manufactured by Nippon Steel Carbon Co., Ltd.)

[0120] Carbon Black C: SRF Carbon Black (trade name "ASAHI#50HG", manufactured by Asahi Carbon Co., Ltd.)

[0121] Calcium carbonate: Trade name "WHITON SB-Aka" (manufactured by Bikawa Powdered Chemical Industry Co., Ltd.)

[0122] Silica: Trade name "Nipsil E-74P" (manufactured by Tosoh Silica Co., Ltd.)

[0123] Plasticizer: Trade name "ADK CIZER RS107" (manufactured by ADEKA Co., Ltd.)

[0124] Zinc oxide: (manufactured by Zhengtong Chemical Industry Co., Ltd.)

[0125] Stearic acid: Trade name "DTST" (manufactured by Miyoshi Oils & Fats Co., Ltd.)

[0126] Anti-aging agent: 2,2,4-trimethyl-1,2-dihydroquinoline polymer (trade name "NOCRAC810-NA", manufactured by Ouchi Shinsei Chemical Co., Ltd.)

[0127] Paraffin wax: Microcrystalline wax (trade name "SUNTIGH R", manufactured by Seiko Chemical Co., Ltd.)

[0128] Vulcanizing agent A: Colloidal sulfur A (manufactured by Tsurumi Chemical Industry Co., Ltd.)

[0129] Vulcanizing agent B: 4,4'-dithiodimorpholine (trade name "VULNOCR", manufactured by Ouchi Shinsei Chemical Co., Ltd.)

[0130] Vulcanization accelerator A: Tetrabenzylthiuram disulfide (trade name "NOCCELER TBZTD", manufactured by Ouchi Shinsei Chemical Co., Ltd.)

[0131] Vulcanization accelerator B: N-cyclohexyl-2-benzothiazolyl sulfinamide (trade name "NOCCELER CZ-P", manufactured by Ouchi Shinsei Chemical Co., Ltd.)

[0132] As shown in Table 1, according to the rubber-metal laminate of this embodiment, since the 100% modulus of the rubber layer is 6.0 MPa or higher, there is relatively little rubber flow in the compression test, and the overflow evaluation score is 4 points or higher in all cases (Examples 1 to 8). Furthermore, for carbon black, regardless of whether medium-particle thermally decomposable carbon black or medium-reinforcing carbon black is used, the overflow score is 4 points or higher in all cases (Examples 1 to 7). Moreover, even when the thickness of the rubber layer is changed to 50 μm, almost no rubber flow is observed in the compression test, and the overflow evaluation score is 5 points (Example 5). Furthermore, even when a plasticizer is added, since the 100% modulus of the rubber layer is 6.0 MPa or higher, almost no rubber flow is observed in the compression test, and the overflow evaluation score is 5 points (Example 8). Furthermore, when calcium carbonate and silica are incorporated, the rubber exhibits less flow during compression testing when the 100% modulus of the rubber layer is above 6.0 MPa, and the overflow evaluation score is 5 points (Example 8).

[0133] In contrast, it can be seen that when the 100% modulus value of the rubber layer is less than 6.0 MPa, the flow of the rubber in the compression test is large, and the score for overflow evaluation is 1 to 3 points (Comparative Examples 1 to 4).

[0134] Based on the above results, according to the above embodiments, by making the 100% modulus of the rubber layer 6.0 MPa or more and the thickness of the rubber layer less than 80 μm, even when compressive stress is applied to the rubber-metal laminate, the overflow of the rubber layer can be prevented, thereby improving the sealing performance of the rubber-metal laminate.

[0135] Industrial availability

[0136] As explained above, the embodiments described above have the following effects: they provide a rubber-metal laminate and gasket that prevents the rubber layer from overflowing under compressive stress and provides excellent sealing performance for the sealed component. The rubber-metal laminate and gasket of this embodiment are particularly suitable for various gaskets such as cylinder head gaskets. Furthermore, the embodiments described above can also be applied to other uses such as compressors, water pumps, motors, batteries, power control units, and converter housings.

[0137] The present invention has been described above as an embodiment, but the embodiments of the present invention are not limited to the content of this embodiment. Furthermore, the above-described constituent elements include elements readily conceived by those skilled in the art, substantially identical elements, and elements of equal scope. Moreover, the above-described constituent elements can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the constituent elements are possible without departing from the spirit of the above-described embodiments.

Claims

1. A rubber-metal laminate, characterized in that, include: Metal components; and A rubber layer disposed on the metal component The rubber layer has a 100% modulus value of 6.0 MPa or higher based on JIS K6251, and the thickness of the rubber layer is less than 80 μm. The rubber layer contains nitrile rubber and carbon black. The carbon black is MT carbon black. The amount of carbon black is 151 parts by mass and 200 parts by mass relative to 100 parts by mass of rubber component.

2. The rubber-metal laminate according to claim 1, wherein, The rubber layer has a 100% modulus value of 8.0 MPa or higher based on JIS K6251.

3. The rubber-metal laminate according to claim 1 or 2, wherein, The elongation value of the rubber layer based on JIS K6251 is 100% or more.

4. The rubber-metal laminate according to claim 1 or 2, wherein, The thickness of the rubber layer is 30 μm or more.

5. The rubber-metal laminate according to claim 1 or 2, wherein, The rubber layer contains carbon black at a rate of 28% or more by mass relative to the total mass of the rubber layer.

6. The rubber-metal laminate according to claim 1 or 2, wherein, The metal component is bonded to the rubber layer by an adhesive selected from the group consisting of phenolic resin and epoxy resin.

7. A gasket, characterized in that, The gasket comprises a rubber-metal laminate according to any one of claims 1 to 6.

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