Member for adhesion and method for manufacturing member for adhesion

Abstract

To secure high adhesive strength when a first member made of vulcanized rubber and a second member made of metal are bonded to each other using a member for adhesion.SOLUTION: A member for adhesion includes a first adhesive layer bonded to a first member, and a second adhesive layer which is laminated on the first adhesive layer and is bonded to a second member. The first adhesive layer contains a first epoxy resin and a first rubber crosslinking agent. The second adhesive layer contains a second epoxy resin, and may contain a second rubber crosslinking agent as an optional component. A percentage content C2 of the second rubber crosslinking agent in the second adhesive layer is lower than a percentage content C1 of the first rubber crosslinking agent in the first adhesive layer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to an adhesive member used for bonding a vulcanized rubber member to a metal member, and a method for manufacturing the same. [Background technology]

[0002] Techniques for bonding rubber members together or rubber members to other members (e.g., metal members) are used in a variety of applications. In particular, when bonding rubber members to other members, it is difficult to obtain high adhesive strength because these members have completely different physical properties. However, high adhesive strength is required depending on the application.

[0003] When bonding an unvulcanized rubber member to another member, a relatively high adhesive strength can be obtained by bonding the unvulcanized rubber material with an adhesive at the same time as vulcanizing the unvulcanized rubber material. On the other hand, when bonding a vulcanized rubber member to another member, the adhesive strength is determined by the adhesive force of the adhesive.

[0004] Patent Document 1 proposes an adhesive composition for vulcanized rubber, which contains an organic polymer having an alkoxysilyl group, an epoxy resin having an aromatic hydrocarbon group, and a silane coupling agent, in which the mass ratio (R:E) of the content R of the organic polymer to the content E of the epoxy resin is 95:5 to 50:50, and the content S of the silane coupling agent is 1.5 to 10 parts by mass per 100 parts by mass of the total of the contents R and E. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2023-82957 A Summary of the Invention [Problem to be solved by the invention]

[0006] When a metal member is bonded to a vulcanized rubber member, the adhesive strength is not improved by vulcanization, and it is difficult to obtain a high adhesive strength compared to when the metal member is bonded to an unvulcanized rubber member. In addition, an adhesive composition suitable for increasing the adhesive strength between either one of the vulcanized rubber member and the adhesive and the metal member may make it difficult to increase the adhesive strength between the other member and the adhesive. Therefore, when a vulcanized rubber member is bonded to a metal member, it may be difficult to ensure a high adhesive strength compared to when the unvulcanized rubber member is bonded. [Means for solving the problem]

[0007] A first aspect of the present disclosure is an adhesive member used for adhering a first member made of vulcanized rubber and a second member made of metal, the bonding member includes a first adhesive layer that is bonded to the first member, and a second adhesive layer that is laminated on the first adhesive layer and is bonded to the second member, the first adhesive layer comprises a first epoxy resin and a first rubber cross-linking agent; The second adhesive layer comprises a second epoxy resin and may comprise a second rubber crosslinking agent as an optional component, and a content C2 of the second rubber crosslinking agent in the second adhesive layer is lower than a content C1 of the first rubber crosslinking agent in the first adhesive layer.

[0008] A second aspect of the present disclosure is a method for producing an adhesive member used for bonding a first member made of vulcanized rubber and a second member made of metal, comprising: the bonding member includes a first adhesive layer that is bonded to the first member, and a second adhesive layer that is laminated on the first adhesive layer and that is bonded to the second member, the first adhesive layer comprises a first epoxy resin and a first rubber cross-linking agent; the second adhesive layer comprises a second epoxy resin and may optionally comprise a second rubber cross-linking agent; The content C2 of the second rubber cross-linking agent in the second adhesive layer is lower than the content C1 of the first rubber cross-linking agent in the first adhesive layer, The manufacturing method relates to a method for manufacturing an adhesive member, including a lamination step of forming a structure in which the first adhesive layer and the second adhesive layer are laminated.

Advantages of the Invention

[0009] When bonding a vulcanized rubber member and a metal member using an adhesive member, high adhesive strength can be ensured.

Embodiments for Carrying Out the Invention

[0010] (1) The adhesive member according to the first aspect of the present disclosure is an adhesive member used for bonding a first member made of rubber after vulcanization and a second member made of metal. The adhesive member includes a first adhesive layer that adheres to the first member, and a second adhesive layer that is laminated on the first adhesive layer and adheres to the second member. The first adhesive layer includes a first epoxy resin and a first rubber crosslinking agent. The second adhesive layer includes a second epoxy resin and may include a second rubber crosslinking agent as an optional component. The content C2 of the second rubber crosslinking agent in the second adhesive layer is lower than the content C1 of the first rubber crosslinking agent in the first adhesive layer.

[0011] As described above, in the present disclosure, first, the adhesive member has a multi-layer structure of a first adhesive layer and a second adhesive layer. In addition, the content C2 of the second rubber crosslinking agent in the second adhesive layer that adheres to the second member is lower than the content C1 of the first rubber crosslinking agent in the first adhesive layer. Since C2 < C1, the first rubber crosslinking agent can firmly bond the first adhesive layer and the first member made of rubber after vulcanization, so that high peel strength between the first adhesive layer and the first member can be obtained.

[0012] In this specification, the peel strength between the first adhesive layer and the first member is evaluated by a 90-degree peel test using a sample of the bonded product (the first sample).

[0013] (2) In the above (1), each of the first adhesive layer and the second adhesive layer may further include an amine-based curing agent. In this case, the mechanical strength of the adhesive layer can be increased, and high adhesive force with each member can be obtained.

[0014] (3) In the above (1) or (2), the content rate of the first epoxy resin in the first adhesive layer may be 30% by mass or more and 85% by mass or less. In this case, a higher adhesive force can be obtained between the first adhesive layer and the first member.

[0015] (4) In any one of the above (1) to (3), the content rate C2 may be 5% by mass or less. When the adhesive layer contains an epoxy resin and a rubber crosslinking agent, it is easy to ensure a relatively high adhesive strength between the rubber-made first member and the adhesive layer and between the metal-made second member and the adhesive layer after vulcanization. Therefore, a relatively high adhesive strength can be obtained at the initial stage of the bonded object. However, when the bonded object is exposed to a high humidity environment, the adhesive strength may decrease. This decrease in adhesive strength due to humidity is particularly significant under a high temperature environment (for example, at a temperature of 60°C or more and 120°C or less). In the present disclosure, in addition to C2 < C1, when the content rate C2 is small (specifically, 5% by mass or less), a decrease in the adhesive force between the second adhesive layer and the second member when the laminate (particularly the second adhesive layer) is exposed to a high humidity environment is suppressed. Therefore, when the bonded object is exposed to a high humidity environment (particularly a high temperature and high humidity environment), a high adhesive strength between the first member and the second member can be ensured.

[0016] The adhesive strength when the bonded object (particularly the second adhesive layer) is exposed to a high humidity environment is evaluated by the tensile shear strength measured after immersing a sample (second sample) of the bonded object of a pair of metal members and the second adhesive layer bonding these in hot water at 100°C for 24 hours, taking it out, and cooling it to 25°C in the atmosphere.

[0017] (5) In any one of the above (1) to (4), the second adhesive layer may further contain a coupling agent. In this case, a higher adhesive force can be obtained between the second adhesive layer and the second member. Therefore, the first member and the second member can be bonded more firmly.

[0018] (6) In the above (5), the coupling agent may have a hydrocarbon group having a reactive functional group. The carbon number of the hydrocarbon group may be 6 or more. The adhesive strength between the second member and the second adhesive layer tends to decrease in a high humidity environment. When the carbon number of the hydrocarbon group of the coupling agent contained in the second adhesive layer is 6 or more, the moisture resistance of the second adhesive layer, which is more susceptible to the influence of humidity, can be increased. Therefore, the decrease in adhesive strength when the bonded object is exposed to a high humidity environment can be further suppressed.

[0019] (7) In any one of the above (1) to (6), a second release film may be attached to a surface of the second adhesive layer facing the second member. (8) In the above item (7), a first release film may be attached to a surface of the first adhesive layer facing the first member. Of the surface Ia on the first member side of the first adhesive layer and the surface IIb on the second member side of the second adhesive layer, when a release film is attached only to the surface IIb, the process of peeling off the release film on the surface Ia side is not necessary, and the process of bonding the first member and the second member using the bonding member can be simplified. In the present disclosure, the stickiness of the surface Ia of the first adhesive layer can also be suppressed, so that the product can be stored or transported with the release film attached to the surface IIb side. In addition, when release films are attached to both the surface Ia and the surface IIb, both the surface Ia and the surface IIb can be protected.

[0020] (9) The present disclosure also includes a method for producing an adhesive member. The method for producing an adhesive member according to a second aspect of the present disclosure is a method for producing an adhesive member used for bonding a first member made of vulcanized rubber and a second member made of metal, comprising the steps of: the bonding member includes a first adhesive layer that is bonded to the first member, and a second adhesive layer that is laminated on the first adhesive layer and that is bonded to the second member, the first adhesive layer comprises a first epoxy resin and a first rubber cross-linking agent; the second adhesive layer comprises a second epoxy resin and may optionally comprise a second rubber cross-linking agent; The content C2 of the second rubber cross-linking agent in the second adhesive layer is lower than the content C1 of the first rubber cross-linking agent in the first adhesive layer, The manufacturing method includes a lamination step of forming a structure in which the first adhesive layer and the second adhesive layer are laminated.

[0021] By using such a manufacturing method, it is possible to easily obtain an adhesive member that can firmly bond a first member and a second member and ensure high adhesive strength when the obtained bonded product is exposed to a high humidity environment. In addition, the obtained adhesive member can also ensure high peel strength between the first adhesive layer and the first member.

[0022] (10) In the above (9), the bonding member may further include a first release film attached to the surface of the first adhesive layer facing the first member, and a second release film attached to the surface of the second adhesive layer facing the second member. The manufacturing method may further include a first step of forming the first adhesive layer on the releasable surface of the first release film, and a second step of forming the second adhesive layer on the releasable surface of the second release film. In the lamination step, the first adhesive layer and the second adhesive layer may be bonded to each other. In such a case, the bonding member can be manufactured more easily using the first release film and the second release film.

[0023] (11) In the above (9), the bonding member may further include a release film attached to one of the surface of the first adhesive layer facing the first member and the surface of the second adhesive layer facing the second member. The manufacturing method may include a step of forming one of the first adhesive layer and the second adhesive layer on the releasable surface of the release film, and a step of forming the other adhesive layer on the surface of the one adhesive layer. In this case, a laminated structure of the first adhesive layer and the second adhesive layer can be manufactured relatively easily.

[0024] The adhesive member and its manufacturing method of the present disclosure, including the above (1) to (11), will be described in more detail below. At least one selected from the components described below can be arbitrarily combined with at least one of the above (1) to (11) relating to the adhesive member and its manufacturing method of the present disclosure, as long as such combination is technically possible.

[0025] [Adhesive materials] The adhesive member includes a first adhesive layer and a second adhesive layer. The adhesive member may be in a sheet or film shape, or may be in another shape. The shape of the adhesive member can be selected depending on the shapes of the first and second members.

[0026] (1st adhesive layer) The first adhesive layer contains a first epoxy resin and a first rubber cross-linking agent, which ensures high adhesive strength between the adhesive member and the first member, and also ensures high adhesive strength between the first adhesive layer and the second adhesive layer.

[0027] The first adhesive layer may contain, as an optional component, at least one selected from the group consisting of, for example, a curable resin other than an epoxy resin, a binder component (such as a rubber component or a resin binder component), a curing agent (including a curing accelerator), a coupling agent, and a filler.

[0028] The first adhesive layer is formed, for example, by applying an adhesive composition containing the components (including precursors) of the first adhesive layer to the surface of a base film, a protective film, or a release film, and drying it. Alternatively, the first adhesive layer may be formed by applying an adhesive composition for forming the first adhesive layer to the surface of a preformed second adhesive layer, and drying it. The adhesive composition may contain a solvent (such as a volatile organic solvent) in addition to the components (including precursors) of the first adhesive layer. Drying may be performed under reduced pressure or by heating. The solvent is removed by drying. The adhesive composition can be prepared by mixing the components (including precursors) of the first adhesive layer. The order in which the components are mixed is not particularly limited. If necessary, mixing may be performed under heating.

[0029] (First epoxy resin) The first epoxy resin may be, for example, a curable epoxy resin (such as an epoxy compound). The epoxy resin is not particularly limited. For example, a bifunctional or trifunctional or higher polyfunctional epoxy compound may be used as the epoxy resin. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, naphthalene type epoxy resin, glycidylamine type epoxy resin, alicyclic epoxy resin, polyether modified epoxy resin, silicone modified epoxy resin, glycidyl ester type epoxy resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, xylylene type epoxy resin, cresol novolac type epoxy resin, tetrakisphenolethane type epoxy resin, and rubber modified epoxy resin may be used. The epoxy resin may be liquid (may have fluidity) or solid at room temperature (for example, 20°C to 35°C). The epoxy resin may be used alone or in combination of two or more. Use of a rubber-modified epoxy resin is advantageous in further improving the adhesive strength between the first member and the first adhesive layer.

[0030] The content of the first epoxy resin in the first adhesive layer may be 30% by mass or more and 85% by mass or less, 35% by mass or more and 85% by mass or less, 50% by mass or more and 85% by mass or less, or 60% by mass or more and 85% by mass or less. When the content of the first epoxy resin is in such a range, a higher adhesive strength can be ensured between the first adhesive layer and the first member. In the adhesive composition, the content of the first epoxy resin in all components other than the solvent is in the above range.

[0031] (Other hardening resins) The first adhesive layer may contain a curable resin (thermosetting resin or photocurable resin) other than the first epoxy resin.

[0032] Examples of the other curable resins include carbodiimide compounds, triazine thiol compounds, bismaleimide compounds, oxetane resins, thermosetting modified polyphenylene ether resins, thermosetting polyimide resins, silicone resins, melamine resins, urea resins, allyl resins, phenolic resins, unsaturated polyester resins, bismaleimide triazine resins, alkyd resins, furan resins, polyurethane resins, aniline resins, etc. These other curable resins may be used alone or in combination of two or more.

[0033] In the first adhesive layer (or adhesive composition), the amount of the other curable resin may be 1 part by mass or more and 250 parts by mass or less, or 10 parts by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the first epoxy resin. The amount of the other curable resin may be determined depending on the application of the adhesive composition.

[0034] (First rubber crosslinking agent) Examples of the first rubber cross-linking agent include dinitroso compounds (p-dinitrosobenzene, paranitroso-N-methyl-N-nitrosoaniline, poly p-dinitrosobenzene, etc.), quinone dioxime compounds, maleimide compounds, alkylphenol resins, etc. However, the first rubber cross-linking agent is not limited to these. The first rubber cross-linking agent may be selected according to the type of rubber component as an optional component. The first rubber cross-linking agent may be used alone or in combination of two or more types.

[0035] The content C1 of the first rubber crosslinking agent in the first adhesive layer may be more than 5% by mass. The content C1 may be 40% by mass or less, or 30% by mass or less. When the content C1 is 8% by mass or more and 40% by mass or less, the adhesive force between the first member and the first adhesive layer is increased, and higher adhesive strength is obtained. The content C1 may be 10% by mass or more and 40% by mass or less. In the adhesive composition, the content of the first rubber crosslinking agent in all components other than the solvent is in the above range.

[0036] (Binder component) Examples of the binder component include a rubber component, a resin binder component (such as a thermoplastic resin or a thermoplastic elastomer), etc. The binder component may be used alone or in combination of two or more kinds.

[0037] (Rubber component) The first adhesive layer may contain a rubber component. By using a rubber component, the flexibility of the first adhesive layer is increased, and the affinity with the first member is increased, so that the adhesive strength between the first member and the first adhesive layer can be further increased.

[0038] Examples of the rubber component include butadiene rubber (BR), isoprene rubber (IR), styrene butadiene rubber (SBR), polychloroprene rubber (CR), nitrile rubber (NBR), millable urethane rubber, epichlorohydrin rubber, butyl rubber, ethylene propylene diene rubber (EPDM), and unvulcanized natural rubber (NR). The rubber component also includes modified rubbers to which reactive functional groups have been introduced (rubber components to which reactive functional groups have been introduced in the above-mentioned rubbers). Examples of rubbers having reactive functional groups include acid-modified rubbers (carboxy-terminated butadiene rubber, carboxy-modified polyisoprene rubber, acid-modified acrylonitrile butadiene rubber, etc.), acid anhydride-modified rubbers (maleic anhydride-modified polybutadiene, maleic anhydride-modified polyisoprene rubber, etc.), epoxy-modified rubbers (epoxy-modified polybutadiene, etc.), (meth)acrylic-modified rubbers (methacrylic-modified isoprene rubber, etc.), and hydroxy-modified rubbers (hydroxy-modified polybutadiene, hydroxy-modified polyisoprene, etc.). The rubber component may be a rubber component that is dissolved in the adhesive composition for forming the first adhesive layer. The rubber component may be used alone or in combination of two or more. When an acid-modified rubber, particularly at least a carboxy-terminated butadiene rubber, is used, a higher adhesive strength between the first member and the first adhesive layer can be ensured.

[0039] (Resin binder component) Examples of the resin binder component include thermoplastic resins. The thermoplastic resin may be an elastomer. Examples of the thermoplastic resin include silicone thermoplastic resins (such as silicone rubber and epoxy-modified silicone), polyester thermoplastic resins, polyamide thermoplastic resins (including polyether ester amides), acrylic thermoplastic resins, phenoxy resins, polyolefin resins, polyurethane resins, blocked isocyanates, polyether resins, thermoplastic polyimide resins, polyvinyl alcohol resins, butyral resins, vinyl chloride, cellulose, thermoplastic epoxy resins, and thermoplastic phenolic resins.

[0040] The acrylic thermoplastic resin contains a (meth)acrylate unit. Examples of the (meth)acrylate unit include an alkyl (meth)acrylate unit. Examples of the alkyl (meth)acrylate unit include C 1-6 Examples include alkyl (meth)acrylate units (ethyl (meth)acrylate units, propyl (meth)acrylate units, butyl (meth)acrylate units, etc.), and C 1-4 It may be an alkyl (meth)acrylate unit. Incidentally, (meth)acrylate may mean acrylate or methacrylate, or both acrylate and methacrylate. Acrylic thermoplastic resins include, but are not limited to, polymethyl acrylate, polymethyl methacrylate (PMMA), and the like.

[0041] The thermoplastic resin may have a reactive functional group or may be modified. Examples of the reactive functional group include an epoxy group, a carboxy group, a hydroxy group, an amino group (including an imino group), an amide group, a nitrile group, and a group having a polymerizable carbon-carbon unsaturated bond (e.g., a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, etc.).

[0042] Examples of thermoplastic elastomers include acid-modified elastomers, acid anhydride-modified elastomers (styrene-maleic anhydride copolymers, olefin-maleic anhydride copolymers, olefin-itaconic anhydride copolymers, maleic anhydride-modified polypropylene, maleic anhydride-modified hydrogenated styrene-based thermoplastic elastomers (SEBS), etc.), amine-modified elastomers (amine-modified SEBS, aminoethylated acrylic polymers, polyallylamine-based elastomers, etc.), epoxy-modified elastomers (epoxy-modified styrene butadiene styrene copolymers (ESBS), etc.), silicone-based elastomers with reactive functional groups introduced therein, elastomers having oxazoline rings such as styrene-vinyl oxazoline copolymers, elastomers having hydroxyl groups such as polyhydroxypolyolefin-based elastomers, phenoxy resin-based elastomers, etc. These may be used alone or in combination of two or more.

[0043] The resin binder component may be used alone or in combination of two or more kinds.

[0044] The Mw of the resin binder component may be 5000 or more and 2,000,000 or less, or 10,000 or more and 1,500,000 or less. When the Mw of the binder component is in such a range, the toughness of the first adhesive layer can be increased. Also, the adhesive strength between the first member and the first adhesive layer can be further increased.

[0045] In this specification, the weight average molecular weight Mw is a weight average molecular weight calculated in terms of polystyrene measured by gel permeation chromatography (GPC).

[0046] In this specification, Mw can be determined, for example, by the following procedure. The component to be measured for Mw is dissolved in a solvent to prepare a measurement sample. The solvent is selected from liquid media capable of dissolving the component depending on the type of component. The measurement sample is used to measure GPC under the following conditions to determine Mw. Equipment: SHODEX, SYSTEM-21H Detector: RI detector Mobile phase: Tetrahydrofuran Flow rate: 1mL / min Column: SHODEX, KF-806M, KF-804, KF-803 Column temperature: 40℃ Reference material: Standard polystyrene (The Mw of the standard polystyrene is selected from among commercially available products with a Mw close to that of the component to be measured.)

[0047] In the first adhesive layer (or adhesive composition), the amount of the binder components (rubber component and resin binder component) may be 1 part by mass or more and 100 parts by mass or less, 3 parts by mass or more and 100 parts by mass or less, 5 parts by mass or more and 60 parts by mass or less, or 5 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the first epoxy resin. When the amount of the binder component is in such a range, a higher adhesive strength between the first member and the first adhesive layer can be ensured. The first adhesive layer may contain both the rubber component and the resin binder component, or may contain either one of them.

[0048] (hardening agent) Examples of the curing agent include phenol-based curing agents (e.g., phenolic resins), amine-based curing agents (dicyandiamide-based curing agents (e.g., dicyandiamide), imidazole derivatives, urea-based curing agents (DCMU), etc.), organic acid hydrazide-based curing agents, polyamine salt-based curing agents, and acid anhydride-based curing agents. Modified amines and the like may be used as the curing agent. The curing agents may be used alone or in combination of two or more. The above curing agents may be used as curing accelerators.

[0049] The first adhesive layer preferably contains at least an amine-based curing agent (such as a dicyandiamide-based curing agent, an imidazole derivative, or a urea-based curing agent (DCMU)). Among these, a latent curing agent is preferable. The melting point of the latent curing agent may be, for example, 60 to 150°C. As the curing agent, an amine-based curing agent that is solid at room temperature (for example, a temperature of 20°C to 35°C) may be used. The amine-based curing agent may be microencapsulated. The above curing agents may be used as curing accelerators.

[0050] The amount of the curing agent is determined depending on, for example, the epoxy equivalent of the first epoxy resin, the amount of reactive groups possessed by the other curable resins, and the like.

[0051] (Coupling Agent) The first adhesive layer (or adhesive composition) may contain a coupling agent (first coupling agent). Examples of the first coupling agent include a silane coupling agent and a titanate coupling agent. Silane coupling agents are often used as the first coupling agent because they are easily available and relatively inexpensive.

[0052] The silane coupling agent usually has an alkoxy group. The silane coupling agent may have a functional group (such as a reactive functional group) other than the alkoxy group. Examples of the functional group include a carboxy group, an acid anhydride group, an amino group, an oxazoline ring, a hydroxy group, an epoxy group (including a glycidyl group, a glycidoxy group, etc.), an oxetane group, an isocyanate group, an acryloyl group, a methacryloyl group, a vinyl group, and a mercapto group. A silane coupling agent having an alkoxysilyl group in a polymer side chain may be used. The first silane coupling agent may have a hydrocarbon group (first hydrocarbon group) having the above-mentioned reactive functional group (first reactive functional group). The first hydrocarbon group may be any of aliphatic, alicyclic, and aromatic. Examples of the first hydrocarbon group include an alkyl group (such as a methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, and pentyl group). The number of carbon atoms in the first hydrocarbon group may be 10 or less, less than 6, 5 or less, or 4 or less. The first hydrocarbon group has one or more carbon atoms.

[0053] Examples of the first silane coupling agent include glycidoxy alkyl trialkoxy silane (such as 3-glycidoxy propyl trimethoxy silane), 2-(3,4-epoxy cyclohexyl) ethyl trimethoxy silane, vinyl triethoxy silane, amino triethoxy silane, 3-isocyanate propyl triethoxy silane, mercaptopropyl trimethoxy silane, 5-norbornene carboxypropyl (trimethoxy) silane, 3-methacryloxy propyl trimethoxy silane, trimethoxy silyl propyl succinic anhydride, alkoxy silyl group-containing acrylic polymer, alkoxy silyl group-containing silicone oligomer, etc. Since the first epoxy resin is used, at least a silane coupling agent having an epoxy group (such as glycidoxy alkyl trialkoxy silane, 2-(3,4-epoxy cyclohexyl) ethyl trimethoxy silane) may be used as the first coupling agent. The glycidoxy alkyl trialkoxy silane is glycidoxy C 1-5 Alkyltri C 1-4 It may be an alkoxysilane, and glycidoxy C 1-5 Alkyltri C 1-2 The number of carbon atoms in the alkyl group in the glycidoxyalkyl group may be within the above range.

[0054] The first coupling agent may be used alone or in combination of two or more kinds.

[0055] In the first adhesive layer (or adhesive composition), the amount of the first coupling agent may be 0.1 parts by mass or more and 15 parts by mass or less, 0.5 parts by mass or more and 10 parts by mass or less, or 0.5 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the first epoxy resin. When the first adhesive layer (or adhesive composition) contains a curable resin other than the first epoxy resin, the amount of the first coupling agent may be within the above numerical range relative to 100 parts by mass of the total amount of this curable resin and the first epoxy resin.

[0056] (Filler) The first adhesive layer (or adhesive composition) may contain a filler. The filler may be either an organic filler (e.g., resin particles, etc.) or an inorganic filler (e.g., inorganic particles, etc.). Examples of inorganic fillers include metal compounds (silica, alumina, titania, zeolite, talc, etc.) and inorganic metal salts (calcium carbonate, etc.). However, the filler is not limited to these.

[0057] In the first adhesive layer (or adhesive composition), the amount of the filler can be selected depending on the type of filler and the application of the adhesive member. The amount of the filler may be 0.1 parts by mass or more and 100 parts by mass or less, or 10 parts by mass or more and 40 parts by mass or less, relative to 100 parts by mass of the first epoxy resin. The amount of the filler relative to 100 parts by mass of the total amount of the first epoxy resin and the other curable resin may be within the above range.

[0058] The thickness of the first adhesive layer may be 1 μm or more and 100 μm or less, 5 μm or more and 50 μm or less, or 10 μm or more and 30 μm or less. When the thickness of the first adhesive layer is in such a range, a higher adhesive strength between the first member and the first adhesive layer is easily obtained.

[0059] The first adhesive layer may have a single layer structure or a multilayer structure. In the first adhesive layer having a multilayer structure, at least two adjacent layers may have different compositions.

[0060] (Second adhesive layer) The second adhesive layer includes a second epoxy resin. By using the second epoxy resin, it is possible to ensure high adhesive strength between the second metallic member and the second adhesive layer, and also to ensure high adhesive strength between the first adhesive layer and the second adhesive layer.

[0061] The second adhesive layer may contain a second rubber crosslinking agent as an optional component. The second adhesive layer may not contain the second rubber crosslinking agent. In the present disclosure, the content C1 of the first rubber crosslinking agent in the first adhesive layer and the content C2 of the second rubber crosslinking agent in the second adhesive layer satisfy the relationship C2 < C1. Thereby, high peel strength between the first adhesive layer and the first member can be obtained, and high adhesive strength between the second adhesive layer and the second member can be obtained.

[0062] The second adhesive layer may contain at least one selected from the group consisting of, for example, other curable resins other than epoxy resins, binder components (such as rubber components, resin binder components), curing agents (including curing accelerators), coupling agents, and fillers as optional components.

[0063] The second epoxy resin and the second rubber crosslinking agent are each selected from the first epoxy resin and the first rubber crosslinking agent of the first adhesive layer. For other constituent components, they can also be selected from the constituent components in the first adhesive layer. The amount or content of each constituent component may also be selected from the ranges described for the first adhesive layer (or the adhesive composition).

[0064] The second adhesive layer is formed in accordance with the case of the first adhesive layer. More specifically, an adhesive composition for forming the second adhesive layer may be applied to the surface of a base film, a protective film, or a release film and dried to form the second adhesive layer. Alternatively, an adhesive composition for forming the second adhesive layer may be applied to the surface of the formed first adhesive layer and dried to form the second adhesive layer. Thereby, a laminated structure of the first adhesive layer and the second adhesive layer is formed, and an adhesive member is obtained. Further, the first adhesive layer and the second adhesive layer formed separately may be overlapped and, if necessary, pressure-bonded under heating to form the above laminated structure (specifically, the adhesive member).

[0065] The content C2 of the second rubber crosslinking agent in the second adhesive layer is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. When C2 is in this range, the second adhesive layer can ensure high adhesive strength when the bonded article is exposed to a high humidity environment, and high tensile tip strength can be obtained. In the adhesive composition forming the second adhesive layer, the content of the second rubber crosslinking agent in all components other than the solvent is in the above range.

[0066] The second adhesive layer may contain a curing agent (including a curing accelerator). The second adhesive layer preferably contains at least an amine-based curing agent as a curing agent. For the curing agent and the amine-based curing agent, the description of the first adhesive layer can be referred to.

[0067] The second adhesive layer may contain a second coupling agent. This can further increase the adhesive strength between the second adhesive layer and the second member, and between the second adhesive layer and the first adhesive layer. As the second coupling agent, the coupling agents exemplified for the first coupling agent may be used. In the second adhesive layer (or adhesive composition), the amount of the second coupling agent relative to 100 parts by mass of the second epoxy resin can be selected from the range described for the amount of the first coupling agent relative to 100 parts by mass of the first epoxy resin in the first adhesive layer.

[0068] The second coupling agent preferably has a hydrocarbon group (second hydrocarbon group) having a reactive functional group (second reactive functional group). In this case, it is easy to ensure a higher adhesive strength between the second adhesive layer and the second member. For the second hydrocarbon group having the second reactive functional group, the explanation of the first hydrocarbon group having the first reactive functional group can be referred to. From the viewpoint of ensuring a higher moisture resistance of the second adhesive layer and ensuring a high adhesive strength when the bonded object is exposed to a high humidity environment, it is preferable that the number of carbon atoms of the second hydrocarbon group is greater than the number of carbon atoms of the first hydrocarbon group. The number of carbon atoms of the second hydrocarbon group may be 6 or more, or may be 8 or more. As the second hydrocarbon group, an alkyl group having a carbon number of 6 or more (or 8 or more), such as a hexyl group, an octyl group, or a decyl group, is preferable. In this case, a higher moisture resistance of the second adhesive layer is obtained. The number of carbon atoms of the second hydrocarbon group (such as an alkyl group) may be 16 or less.

[0069] As the second coupling agent, it is preferable to use at least a silane coupling agent having an epoxy group. As the silane coupling agent having an epoxy group, glycidoxyalkyltrialkoxysilane is preferable. The glycidoxyalkyltrialkoxysilane is glycidoxyC 6-16 Alkyltri C 1-4 It may be an alkoxysilane, and glycidoxy C 6-16 Alkyltri C 1-2 The lower limit of the number of carbon atoms in the alkyl group in the glycidoxyalkyl group may be 8.

[0070] The second coupling agent may be used alone or in combination of two or more kinds.

[0071] The second adhesive layer (or adhesive composition) may contain a filler. For the filler, reference may be made to the description of the filler and its amount in the first adhesive layer.

[0072] The thickness of the second adhesive layer may be 1 μm or more and 100 μm or less, 5 μm or more and 50 μm or less, or 10 μm or more and 30 μm or less. When the thickness of the second adhesive layer is in such a range, a higher adhesive strength between the second member and the second adhesive layer is easily obtained.

[0073] The second adhesive layer may have a single layer structure or a multilayer structure. In the multilayer structure, at least two adjacent layers of the second adhesive layer may have different compositions.

[0074] (Release film, base film, protective film) The bonding member may include at least one selected from the group consisting of a release film, a base film, and a protective film, in addition to the first adhesive layer and the second adhesive layer. These are used to form or protect the first adhesive layer or the second adhesive layer during the manufacturing process of the bonding member. The release film has at least a release-treated surface that comes into contact with the surface of the first adhesive layer or the second adhesive layer. The release treatment is performed, for example, by applying a release agent (such as silicone oil). Since the surface of each adhesive layer is used for adhesion to the first member or the second member, it is preferable that the surfaces of the base film and the protective film that come into contact with each adhesive layer are release-treated like the release film.

[0075] In the adhesive member, for example, a release film may be attached to both the surface Ia of the first adhesive layer facing the first member and the surface IIb of the second adhesive layer facing the second member, or may be attached to only one of them. For example, a release film may be attached to at least the surface IIb.

[0076] (First member) The first member is made of vulcanized rubber. Examples of rubber materials constituting the first member include natural rubber, nitrile rubber, silicone rubber, fluororubber, urethane rubber, acrylic rubber, isoprene rubber, styrene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-vinyl acetate rubber, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene rubber, epichlorohydrin rubber, and polysulfide rubber. The first member is made of vulcanized rubber obtained by vulcanizing these rubbers. However, the above rubber materials are merely examples and are not limited to these.

[0077] (Second member) The second member is made of a metal. The composition of the second adhesive layer may be determined according to the type of metal material constituting the second member. The metal material is not particularly limited, and examples thereof include stainless steel, titanium, titanium alloy, aluminum, aluminum alloy, and nickel alloy.

[0078] In general, it is difficult to ensure high adhesive strength when bonding a first member made of vulcanized rubber and a second member made of metal, but by using the bonding member of the present disclosure, high adhesive strength can be ensured. In particular, high adhesive strength can be ensured when the bonded object is exposed to a high humidity environment.

[0079] [Method of manufacturing adhesive member] The adhesive member of the present disclosure is formed, for example, by a manufacturing method including a lamination step of forming a structure in which a first adhesive layer and a second adhesive layer are laminated.

[0080] The bonding member may further include a first release film attached to the surface Ia of the first adhesive layer on the first member side, and a second release film attached to the surface IIb of the second adhesive layer on the second member side. In this case, for example, the bonding member is formed by manufacturing method A. Manufacturing method A includes a first step of forming a first adhesive layer on the releasable surface of the first release film, and a second step of forming a second adhesive layer on the releasable surface of the second release film. Then, in a lamination step (third step), the first adhesive layer and the second adhesive layer are bonded to each other to form a structure in which these adhesive layers are laminated.

[0081] In the third step of the manufacturing method A, the exposed surface of the first adhesive layer and the exposed surface of the second adhesive layer may be overlapped and pressure-bonded. The pressure-bonding may be performed under heating, if necessary.

[0082] Production method A may optionally include, after the third step, a step of peeling off one of the first release film and the second release film (for example, the first release film).

[0083] The bonding member may further include a release film (first release film or second release film) attached to either the surface Ia of the first adhesive layer on the first member side or the surface IIb of the second adhesive layer on the second member side. In this case, the bonding member is manufactured by, for example, manufacturing method B. Manufacturing method B includes a step of forming one of the first adhesive layer and the second adhesive layer on the releasable surface of the release film, and a step of forming the other adhesive layer on the surface of one adhesive layer. In manufacturing method B, a structure in which both adhesive layers are laminated is formed in the step of forming the other adhesive layer. Therefore, it can be said that the other adhesive layer is formed in the above-mentioned lamination step.

[0084] The manufacturing method B may include a step of attaching a release film to protect the exposed surface of the other adhesive layer after forming the other adhesive layer, if necessary. Alternatively, in the manufacturing method B, a release film to protect the exposed surface of the other adhesive layer may be attached while forming the other adhesive layer, if necessary. The attachment of the release film may be performed by pressure bonding. The pressure bonding may be performed under heating, if necessary.

[0085] In both the manufacturing method A and the manufacturing method B, the formation of each adhesive layer is carried out, for example, by applying an adhesive composition containing the constituent components of the adhesive layer to the surface of the release film (or one of the adhesive layers) and drying it. The drying may be carried out, for example, under reduced pressure or under heating.

[0086] In the step of forming each adhesive layer, or prior to the step of forming each adhesive layer, an adhesive composition for forming each adhesive layer is prepared. The manufacturing method may include a step of preparing such an adhesive composition.

[0087] In the adhesive member, each adhesive layer may be in an uncured state, or in a semi-cured state, of the epoxy resin and other curable resin.

[0088] The first member and the second member are laminated together with the adhesive member interposed therebetween, and then heated under pressure to harden each adhesive layer of the adhesive member, thereby obtaining an adhered product.

[0089] [Example] The present invention will be specifically described below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0090] Examples 1 to 4 and Comparative Example 1 (1) Preparation of adhesive composition for adhesive layer Each of the adhesive compositions for the first adhesive layer and the second adhesive layer was prepared by mixing the materials shown in Table 1 in the amounts (parts by mass) shown in Table 1.

[0091] (2) Preparation of adhesive materials The adhesive composition for the first adhesive layer was applied to the release-treated surface (one side) of the release film with an applicator so that the film thickness after drying would be 25 μm. The resulting coating film was dried at 80° C. for 10 minutes to form the first adhesive layer. As the release film, a polyethylene terephthalate (PET) film (200 mm long x 200 mm wide x 50 μm thick) with a release-treated surface was used. The first adhesive layer was formed in the center of the length of the release film to a size of 150 mm long x 150 mm wide.

[0092] Using the same procedure and conditions as above, the adhesive composition for the second adhesive layer was applied to the release-treated surface of another release film and dried to form a second adhesive layer.

[0093] The first adhesive layer and the second adhesive layer were overlapped so that the exposed surfaces of the two layers were in contact with each other, and were bonded together using a laminator at 50° C. In this manner, an adhesive member was obtained.

[0094] The release film on the second adhesive layer side of the obtained adhesive member was peeled off, and the second adhesive layer was attached to the center of one side of a cold-rolled steel plate (SPCC, length 60 mm x width 20 mm x thickness 2 mm) as the second member in the length direction. Next, the release film on the first adhesive layer side was peeled off, and the second adhesive layer was attached to the center of one side of a vulcanized natural rubber sheet (length 120 mm x width 20 mm x thickness 5 mm). The size of the part where the adhesive layers were attached to each other was length 30 mm x width 20 mm. The part where the adhesive layers were attached to each other was clamped and fixed with a clip, heated in an oven at 150 ° C for 60 minutes to harden each adhesive layer, and cooled to 25 ° C in the oven. In this way, a first sample of the adhesive was obtained.

[0095] (3) Evaluation Using the first sample obtained above, a 90-degree peel test was performed in accordance with JIS K6256-2: 2013. The peel strength (N / mm) was measured, and the peeling was visually observed and evaluated (judged) according to the following criteria. A: Peeling accompanied by the destruction of the first member (vulcanized natural rubber sheet) occurred. B: Peeling occurred at the interface between the first member and the first adhesive layer.

[0096] The evaluation results are shown in Table 1. In Table 1, A1 to A4 are Examples 1 to 4, and B1 is Comparative Example 1.

[0097]

Table 1

[0098] As shown in Table 1, in Comparative Example 1 (B1) where C2 = C1, the peel strength was low, and peeling occurred at the interface between the first member and the bonding member (Judgment B). On the other hand, in Examples 1 to 4 (A1 to A4) where C2 < C1, a peel strength more than three times that of Comparative Example 1 was obtained, and peeling occurred within the first member (rubber fracture). Thus, in the examples where C2 < C1, the first member and the bonding member were firmly adhered, and a high peel strength was obtained.

[0099] 《Reference Examples 1 to 7》 An adhesive composition for the second adhesive layer was prepared in the same manner as in Example 1, except that the materials shown in Table 2 were used in the amounts (parts by mass) shown in Table 2.

[0100] The adhesive composition was applied to one end of one side of a cold-rolled steel plate (SPCC, length 150 mm × width 25 mm × thickness 1.6 mm) in the length direction so that the thickness after drying was about 25 μm. The obtained coating film was dried at 100 ° C for 2 minutes to form a second adhesive layer. The second adhesive layer was formed to a size of length 10 mm × width 25 mm. Another cold-rolled steel plate (SPCC, length 150 mm × width 25 mm × thickness 1.6 mm) was prepared, one end was overlapped on the second adhesive layer, and one end of the cold-rolled steel plate was fixed with a clip while sandwiching the second adhesive layer. At this time, each cold-rolled steel plate was overlapped so that the other end was located on the opposite side to the second adhesive layer. The laminate in the state fixed with the clip was heated at 150 ° C for 90 minutes to harden the second adhesive layer. In this way, six second samples for measuring tensile shear strength were prepared.

[0101] The tensile shear strength of the three second samples was measured immediately after the samples were prepared, and the average value (initial tensile shear strength S0) was calculated. The remaining three second samples were immersed in hot water at 100°C immediately after preparation, and this state was maintained for 24 hours. The second samples taken out of the hot water were cooled to 25°C in the air, and the tensile shear strength was measured, and the average value (tensile shear strength after hot water treatment S1) was calculated. Then, for the tensile shear strength S1 after hot water, the decrease in the adhesive strength when the second adhesive layer is exposed to a high humidity environment was evaluated (judged) according to the following criteria in relation to the initial tensile shear strength S0. The adhesive strength between the first adhesive layer and the first member is hardly decreased by the high humidity environment. Therefore, when the judgment result of the tensile shear strength S1 is excellent, it can be judged that the adhesive strength when the adhesive is exposed to a high humidity environment is also high for the bonded object in which the first member and the second member are bonded using an adhesive member. A: S1 ≧ 0.95 × S0 is satisfied. B: 0.80×S0≦S1<0.95×S0 C: 0.50×S0≦S1<0.80×S0 is satisfied. D: S1<0.50×S0

[0102] The tensile shear strength is a tensile shear adhesive strength (MPa) determined by a shear adhesion test in accordance with JIS K 6850: 1999. The test was carried out using an Instron tensile tester at a tensile speed of 5.0 mm / min.

[0103] The results are shown in Table 2. In Table 2, R1 to R7 represent Reference Examples 1 to 7. For the components used in Table 2, see the explanation for Table 1.

[0104] [Table 2]

[0105] As shown in Table 2, from the viewpoint of ensuring high adhesive strength of the second adhesive layer when exposed to a high humidity environment, the content of the rubber crosslinking agent in the second adhesive layer is, for example, preferably 5 mass% or less, more preferably 3 mass% or less, and even more preferably 1 mass% or less. From the same viewpoint, the second coupling agent contained in the second adhesive layer preferably has a hydrophobic group with relatively high hydrophobicity, and more preferably has a hydrocarbon group with 6 or more carbon atoms (preferably 8 or more). [Industrial Applicability]

[0106] The adhesive member of the present disclosure can bond a first member made of rubber and a second member made of metal with high adhesive strength after vulcanization, and the resulting bonded product has high peel strength. Therefore, it can be used in various applications for bonding these members. The adhesive member is also suitable for use in, for example, seismic isolation applications (such as seismic isolation rubber), earthquake resistance applications, and vibration prevention applications (such as vibration prevention parts). However, the applications of the adhesive member are not limited to these.

Claims

1. An adhesive member used for adhering a first member made of vulcanized rubber and a second member made of metal, the bonding member includes a first adhesive layer that is bonded to the first member, and a second adhesive layer that is laminated on the first adhesive layer and is bonded to the second member, the first adhesive layer comprises a first epoxy resin and a first rubber cross-linking agent; an adhesive member, wherein the second adhesive layer contains a second epoxy resin and may contain a second rubber crosslinking agent as an optional component, and a content C2 of the second rubber crosslinking agent in the second adhesive layer is lower than a content C1 of the first rubber crosslinking agent in the first adhesive layer.

2. The adhesive member according to claim 1 , wherein each of the first adhesive layer and the second adhesive layer further contains an amine-based curing agent.

3. The bonding member according to claim 1 , wherein a content of the first epoxy resin in the first adhesive layer is 30% by mass or more and 85% by mass or less.

4. The bonding member according to claim 1 , wherein the content C2 is 5 mass % or less.

5. The adhesive member according to claim 1 or 2, wherein the second adhesive layer further contains a coupling agent.

6. The coupling agent has a hydrocarbon group having a reactive functional group, The adhesive member according to claim 5 , wherein the hydrocarbon group has 6 or more carbon atoms.

7. The bonding member according to claim 1 or 2, wherein a second release film is attached to a surface of the second adhesive layer facing the second member.

8. The bonding member according to claim 7 , further comprising a first release film attached to a surface of the first adhesive layer on the side of the first member.

9. A method for manufacturing an adhesive member used for bonding a first member made of vulcanized rubber and a second member made of metal, comprising the steps of: the bonding member includes a first adhesive layer that is bonded to the first member, and a second adhesive layer that is laminated on the first adhesive layer and is bonded to the second member, the first adhesive layer comprises a first epoxy resin and a first rubber cross-linking agent; the second adhesive layer comprises a second epoxy resin and may optionally comprise a second rubber cross-linking agent; A content C2 of the second rubber cross-linking agent in the second adhesive layer is lower than a content C1 of the first rubber cross-linking agent in the first adhesive layer, The manufacturing method is a method for manufacturing an adhesive member, the method including a lamination step of forming a structure in which the first adhesive layer and the second adhesive layer are laminated.

10. the bonding member further includes a first release film attached to a surface of the first adhesive layer facing the first member, and a second release film attached to a surface of the second adhesive layer facing the second member, The manufacturing method further comprises: a first step of forming the first adhesive layer on a releasable surface of the first release film; A second step of forming the second adhesive layer on a releasable surface of the second release film, The method for producing an adhesive member according to claim 9 , wherein the first adhesive layer and the second adhesive layer are bonded to each other in the laminating step.

11. the adhesive member further includes a release film attached to one of a surface of the first adhesive layer facing the first member and a surface of the second adhesive layer facing the second member, forming one of the first adhesive layer and the second adhesive layer on a releasable surface of the release film; The method for producing a bonding member according to claim 9 , further comprising: forming another adhesive layer on a surface of the one adhesive layer.

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