Thermosetting adhesive sheets

Abstract

The present invention provides a thermosetting adhesive sheet that allows for easy peeling of a release liner from the adhesive surface when the release liner is peeled off, resulting in excellent operability and minimal adhesive spillage. The thermosetting adhesive sheet 1 has an elastic modulus G' of 150-3000 kPa at 20°C and an elastic modulus G' of 1 kPa or more at 80°C. Preferably, the thermosetting adhesive sheet 1 contains epoxy resin (a) with an epoxy equivalent of 200-800 g / eq and rubber-modified epoxy resin (b).

Description

[Technical Field]

[0001] This invention relates to a thermosetting adhesive sheet. [Previous Technology]

[0002] In recent years, for example, in order to bond metal components to other components, thermosetting double-sided adhesive sheets are sometimes used. These sheets can be hardened by heating, thereby exerting adhesive force to firmly bond the components together. As such thermosetting adhesive sheets, adhesive sheets containing thermosetting resin and hardener are known, for example (see, for example, Patent Documents 1-3).

[0003] Double-sided adhesive sheets used for bonding and fixing components together typically have release liner applied to both adhesive surfaces to protect them before use. Furthermore, when using a double-sided adhesive sheet, first, one release liner is peeled off, the exposed adhesive surface is adhered to one component, and then the other release liner is peeled off, the exposed adhesive surface is adhered to another component, and so on. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2012-197427 [Patent Document 2] Japanese Patent Application Publication No. 2019-39005 [Patent Document 3] Japanese Patent Application Publication No. Hei 7-157535 [Summary of the Invention]

[0005] [The problem the invention aims to solve]

[0006] Although thermosetting adhesive sheets are cured by heat and firmly bonded to components, they are mostly soft before thermosetting. Therefore, for example, when peeling off a release liner from the two adhesive surfaces of a thermosetting double-sided adhesive sheet while the release liner is protected by the release liner, there is a problem of so-called "adhesive separation", that is, peeling off the adhesive sheet while a portion of the adhesive is still attached to the release liner, resulting in damage to the adhesive sheet interface.

[0007] Furthermore, when one adhesive side of a double-sided adhesive sheet is bonded to a component, and then a release liner bonded to the other adhesive side is peeled off, the following problem exists: sometimes the release liner cannot be peeled off from the adhesive side of the adhesive sheet, and the adhesive sheet and the release liner are peeled off from the bonded component together, that is, the transferability of the adhesive sheet is poor. Therefore, for thermosetting adhesive sheets, it is necessary to be able to easily peel off the release liner while it is bonded to the adhesive side, with excellent operability.

[0008] Furthermore, after the thermosetting adhesive sheet is applied to the component as described above, it is heated to harden the adhesive sheet and firmly bond it to the component. However, when the components that are to be bonded are applied to each other via the thermosetting adhesive sheet, or when the thermosetting adhesive sheet is heated to harden, the adhesive in the adhesive sheet may sometimes flow due to pressure or heat and overflow from between the components, that is, paste overflow occurs.

[0009] Therefore, for thermosetting adhesive sheets, it is necessary to easily peel the release liner from the adhesive surface of the adhesive sheet when peeling it off, ensuring excellent operability and minimizing adhesive spillage. Furthermore, the adhesive sheets disclosed in Patent Documents 1-3 do not mention possessing all of these properties, nor do they disclose thermosetting adhesive sheets possessing the properties satisfied by the thermosetting adhesive sheet of the present invention described later.

[0010] This invention is proposed in view of the above-mentioned circumstances, and its object is to provide a thermosetting adhesive sheet that allows for easy peeling of the release liner from the adhesive surface of the adhesive sheet during peeling, resulting in excellent operability and minimizing adhesive overflow. [Technical Means for Solving the Problem]

[0011] The inventors have conducted research to achieve the above-mentioned objectives and have found that thermosetting adhesive sheets with elastic modulus G' at 20°C and elastic modulus G' at 80°C, respectively, within specific ranges, easily peel off the release liner from the adhesive surface when it is peeled off, exhibiting excellent operability and minimizing adhesive overflow. The present invention is based on these insights.

[0012] That is, the present invention provides a thermosetting adhesive sheet, wherein the elastic modulus G' at 20°C is 150 to 3000 kPa and the elastic modulus G' at 80°C is 1 kPa or more.

[0013] The above-mentioned thermosetting adhesive sheet has an elastic modulus G' of 150 kPa or more at 20°C. Before thermosetting, it has moderate hardness near room temperature. For example, when peeling off one release liner from the two adhesive surfaces of the double-sided adhesive sheet, the release liner exhibits excellent peelability, making it difficult for adhesion and separation to occur, and thus providing excellent workability. Furthermore, with an elastic modulus G' of 3000 kPa or less at 20°C, the thermosetting adhesive sheet has moderate softness near room temperature before thermosetting. When peeling off the release liner from the other adhesive surface of the thermosetting adhesive sheet from one adhesive surface of the sheet to a component, the release liner is easily peeled off along the interface with the sheet, and the workability is excellent.

[0014] Furthermore, the above-mentioned thermosetting adhesive sheet has an elastic modulus G' of 1 kPa or more at 80°C. When pressure or heat is applied before thermosetting, it has sufficient hardness, so the fluidity of the adhesive is low and it is difficult for the adhesive to overflow from between the components.

[0015] Preferably, the above-mentioned thermosetting adhesive sheet contains epoxy resin (a) with an epoxy equivalent of 200-800 g / eq and rubber-modified epoxy resin (b).

[0016] The epoxy resin (a) is preferably selected from one or more of the group consisting of bisphenol type epoxy resin, phenolic varnish type epoxy resin and dimer acid modified epoxy resin.

[0017] The preferred quality ratio of epoxy resin (a) to rubber-modified epoxy resin (b) is 20:80 to 80:20.

[0018] Preferably, the above-mentioned thermosetting adhesive sheet contains 0.5 to 30 parts by weight of epoxy curing agent in 100 parts by weight of the total amount of epoxy resin (a) and rubber-modified epoxy resin (b).

[0019] Preferably, the epoxy curing agent contains dicyandiamide, and the content of dicyandiamide is 0.5 to 20 parts by weight relative to the total of 100 parts by weight of epoxy resin (a) and rubber-modified epoxy resin (b).

[0020] Preferably, the epoxy curing agent contains urea compounds and / or imidazole compounds, and the content of urea compounds and / or imidazole compounds is 1 to 10 parts by mass relative to the total of 100 parts by mass of epoxy resin (a) and rubber-modified epoxy resin (b).

[0021] Preferably, the above-mentioned thermosetting adhesive sheet contains filler.

[0022] The average particle size of the above-mentioned filler is preferably 7 to 50 nm.

[0023] The specific surface area of ​​the filler in each 100 g of the above-mentioned thermosetting adhesive sheet is preferably 600 to 6000 m2.

[0024] The above-mentioned thermosetting adhesive sheet is preferably used to bond together components in which at least one component is a metal component.

[0025] The above-mentioned thermosetting adhesive sheet is preferably used for bonding metal components to each other or metal components to fiber-reinforced resin components. [Effects of the Invention]

[0026] The thermosetting adhesive sheet of the present invention can easily peel off the release liner from the adhesive surface when the release liner is peeled off from the adhesive surface, which has excellent operability and makes it difficult for adhesive to overflow.

Implementation Method

[0028] [Thermosetting Adhesive Sheet] The thermosetting adhesive sheet of the present invention has an elastic modulus G' of 150 to 3000 kPa at 20°C and an elastic modulus G' of 1 kPa or more at 80°C.

[0029] The aforementioned thermosetting adhesive sheet is preferably a double-sided adhesive sheet, and more preferably a so-called "substrate-free" double-sided adhesive sheet without a substrate. Substrate-free double-sided adhesive sheets do not suffer from interlayer damage issues caused by the use of a substrate, and also exhibit excellent conformability to the bonded object. The aforementioned thermosetting adhesive sheet can be used as a single layer for bonding components, or it can be stacked as a laminate of thermosetting adhesive sheets for bonding components. Furthermore, it can also be used as a single-sided adhesive sheet by bonding a substrate layer to the aforementioned thermosetting adhesive sheet.

[0030] Figure 1 is a cross-sectional schematic diagram showing one embodiment of the thermosetting adhesive sheet of the present invention. The thermosetting adhesive sheet 1 shown in Figure 1 is a double-sided adhesive sheet. Release pads 2 and 3 are respectively attached to the two adhesive surfaces of the thermosetting adhesive sheet 1.

[0031] As described above, the elastic modulus G' at 20°C is 150 to 3000 kPa. With an elastic modulus G' of 150 kPa or higher at 20°C, the thermosetting adhesive sheet before heat curing has moderate hardness near room temperature. For example, when peeling off one release liner from the two adhesive surfaces of the double-sided adhesive sheet, the peeling performance is excellent, adhesion separation is difficult, and workability is excellent. With an elastic modulus G' of 3000 kPa or less at 20°C, the thermosetting adhesive sheet before heat curing has moderate softness near room temperature. When peeling off the release sheet from the other adhesive surface from the state where one adhesive surface of the thermosetting adhesive sheet is adhered to a component, the peeling performance is excellent, the release liner can be easily peeled off along the sheet interface, and workability is excellent.

[0032] The elastic modulus G' at 20°C is preferably 200 kPa or more, and more preferably 250 kPa or more. Furthermore, the elastic modulus G' at 20°C is preferably 2000 kPa or less, and more preferably 900 kPa or less.

[0033] As described above, the modulus of elasticity G' of the thermosetting adhesive sheet of the present invention at 80°C is 1 kPa or more. Because the modulus of elasticity G' at 80°C is 1 kPa or more, the thermosetting adhesive sheet before thermosetting has sufficient hardness when pressure or heat is applied, so the fluidity of the adhesive is low and it is difficult for the adhesive to overflow from between components.

[0034] The elastic modulus G' at 80°C is preferably 3 kPa or more, more preferably 7 kPa or more, and even more preferably 10 kPa or more. Furthermore, the elastic modulus G' at 80°C is preferably 500 kPa or less, more preferably 300 kPa or less, and even more preferably 200 kPa or less. If the elastic modulus G' at 80°C is 500 kPa or less (especially 200 kPa or less), the conformability to the unevenness of the bonded body is excellent, and the shear adhesion is excellent.

[0035] The above-mentioned elastic modulus G' at 20°C and the above-mentioned elastic modulus G' at 80°C are the elastic modulus G' of the adhesive sheet before heat curing of the thermosetting adhesive sheet. The above-mentioned elastic modulus G' is determined by dynamic viscoelasticity (DMA) measurement to obtain the storage modulus at 20°C or 80°C.

[0036] Furthermore, in this specification, "before heat curing" refers to the state where the thermosetting adhesive sheet has not undergone curing treatment or where the reaction rate is less than 50% and partially cured. Specifically, the reaction rate of the thermosetting resin sheet can be measured using a differential scanning calorimeter (DSC) to determine the heat of reaction [J / g] when the adhesive sheet (object) and the object (heated object) are heated at a heat-curable temperature from 0°C to 300°C at a heating rate of 10°C / min. The heat of reaction of the object from 0°C to 300°C is taken as the "heat of reaction of the object," and the heat of reaction of the heated object from 0°C to 300°C is taken as the "heat of reaction after heating." The reaction rate is calculated according to the following formula: Reaction rate = Heat of reaction after heating [J / g] ÷ Heat of reaction of the object [J / g] × 100

[0037] The above-mentioned thermosetting adhesive sheet has the property of curing by heat. Therefore, it is preferable that the above-mentioned thermosetting adhesive sheet contains a thermosetting resin.

[0038] The above-mentioned thermosetting resin is a resin having thermosetting functional groups. Examples of such thermosetting resins include: epoxy resin, phenolic resin, amino resin, unsaturated polyester resin, polyurethane resin, silicone resin, thermosetting polyimide resin, melamine resin, alkyd resin, etc. Only one of the above-mentioned thermosetting resins may be used, or two or more may be used.

[0039] Examples of the aforementioned epoxy resins include: bisphenol type epoxy resins, hydrogenated bisphenol type epoxy resins, spirocyclic epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins, fumonisin type epoxy resins, terpene type epoxy resins, glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, phenolic varnish type epoxy resins, trihydroxyphenylmethane type epoxy resins, tetraphenol ethane type epoxy resins, hydantoin type epoxy resins, and triglycidyl isocyanate type epoxy resins. Furthermore, the aforementioned epoxy resins may also be modified epoxy resins such as dimer acid modified epoxy resins, carbamate modified epoxy resins, and rubber modified epoxy resins. Moreover, the aforementioned epoxy resins may also be any of aliphatic epoxy resins, alicyclic epoxy resins, and aromatic epoxy resins, with alicyclic epoxy resins and aliphatic epoxy resins being more preferred.

[0040] Examples of the above-mentioned bisphenol type epoxy resins include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy resin, and bisphenol AF type epoxy resin. Examples of the above-mentioned glycidyl ether type epoxy resins include: tris(glycidyloxyphenyl)methane and tetra(glycidyloxyphenyl)ethane. Examples of the above-mentioned glycidylamine type epoxy resins include: tetraglycidyldiaminodiphenylmethane. Examples of the above-mentioned phenolic varnish type epoxy resins include: cresol phenolic varnish type epoxy resin, phenolic varnish type epoxy resin, α-naphthol phenolic varnish type epoxy resin, brominated phenolic varnish type epoxy resin, and o-cresol phenolic varnish type epoxy resin. Of the aforementioned epoxy resins, from the viewpoint of excellent workability, bisphenol-type epoxy resins, phenolic varnish-type epoxy resins, and dimer acid-modified epoxy resins are preferred; more preferably, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, phenolic varnish-type epoxy resins, and dimer acid-modified epoxy resins are also preferred. Furthermore, the aforementioned bisphenol-type epoxy resins may also have a block structure containing a softening component between the bisphenol backbone. Examples of such softening components include linear hydrocarbon groups or ethylene glycol groups, propylene glycol groups, butylene glycol groups, and other alkyl glycol groups.

[0041] Among the above-mentioned thermosetting resins, epoxy resin is preferred. The epoxy resin is preferably an epoxy resin containing an epoxy equivalent of 200 to 800 g / eq, and more preferably a rubber-modified epoxy resin. Furthermore, in this specification, the epoxy resin containing an epoxy equivalent of 200 to 800 g / eq is sometimes referred to as "epoxy resin (a)" and the rubber-modified epoxy resin is sometimes referred to as "rubber-modified epoxy resin (b)". If epoxy resin (a) is included, since the crosslinking points in epoxy resin (a) are appropriately spaced, the modulus of elasticity G' of the thermosetting adhesive sheet at 20°C is easily within the above-mentioned range. Furthermore, if rubber-modified epoxy resin (b) is included together with epoxy resin (a), the thermosetting adhesive sheet containing epoxy resin (a) can be strengthened to more stably maintain the sheet shape. Epoxy resin (a) and rubber-modified epoxy resin (b) may be used alone or in combination with more than one type.

[0042] Furthermore, epoxy resin (a) and rubber-modified epoxy resin (b) are different resins. For example, epoxy resin (a) may be any epoxy resin other than rubber-modified epoxy resin, and the epoxy equivalent of rubber-modified epoxy resin (b) may be less than 200 g / eq or more than 800 g / eq.

[0043] (Epoxy Resin (a)) The epoxy equivalent of the epoxy resin (a) is 200 to 800 g / eq. Preferably, the epoxy equivalent is 200 to 500 g / eq, more preferably 200 to 400 g / eq. Also, the epoxy equivalent can be 400 to 750 g / eq or 500 to 700 g / eq. If the epoxy equivalent is 200 g / eq or higher, the thermosetting adhesive sheet has moderate hardness, making it less prone to adhesion separation when peeling off the release liner, and also less prone to adhesive overflow. If the epoxy equivalent is 800 g / eq or lower, the thermosetting adhesive sheet has moderate softness, exhibiting excellent adhesion to the substrate when one adhesive surface of the thermosetting adhesive sheet is bonded to the substrate, and even better transfer properties when peeling off the release liner bonded to the other adhesive surface.

[0044] The epoxy resin (a) may be a solid epoxy resin at room temperature, a liquid epoxy resin at room temperature, or a semi-solid epoxy resin at room temperature. From the viewpoint of easily obtaining a thermosetting adhesive sheet with excellent transfer properties and low risk of overflow, a semi-solid epoxy resin is preferred. Furthermore, "semi-solid" refers to a resin that is solid at 20°C and liquid at 40°C. Furthermore, from the viewpoint of easily obtaining a thermosetting adhesive sheet with excellent transfer properties and low risk of overflow, the epoxy resin (a) is preferably a resin with a softening point of 70°C or lower. Furthermore, the epoxy resin (a) is preferably a semi-solid epoxy resin or an epoxy resin with a softening point of 70°C or lower.

[0045] As for epoxy resin (a), from the viewpoint of excellent operability or ease of acquisition, bisphenol type epoxy resin, phenolic varnish type epoxy resin, dimer acid modified epoxy resin are preferred, and bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic varnish type epoxy resin, dimer acid modified epoxy resin are even more preferred.

[0046] (Rubber-modified epoxy resin (b)) The rubber-modified epoxy resin (b) contains a rubber component in the epoxy resin. Examples of the rubber component include: butadiene rubber, acrylic rubber, silicone rubber, butyl rubber, isoprene rubber, styrene rubber, chloroprene rubber, NBR, SBR, IR, EPR, carboxyl-terminated butadiene-acrylonitrile copolymer rubber (CTBN), styrene-butadiene elastomers, etc. Only one of the above rubber components may be used, or two or more may be used. From the viewpoint that the thermosetting adhesive sheet can be strengthened more sufficiently, the rubber-modified epoxy resin (b) is preferably CTBN-modified epoxy resin.

[0047] Examples of epoxy resins in rubber-modified epoxy resin (b) include those mentioned above. Among them, bisphenol type epoxy resin is preferred, and bisphenol A type epoxy resin is more preferred.

[0048] The epoxy equivalent of the rubber-modified epoxy resin (b) is preferably 1000-2000 g / eq, more preferably 1200-1800 g / eq. If the epoxy equivalent is within the above range, the modulus of elasticity G' of the thermosetting adhesive sheet at 20°C is likely to be within the above range. Furthermore, if the epoxy equivalent is 1000 g / eq or more, the thermosetting adhesive sheet has appropriate hardness, making it more difficult for adhesive separation to occur when the release liner is peeled off, and also making it more difficult for adhesive overflow to occur.

[0049] Commercially available products can be used for rubber-modified epoxy resin (b). Examples of commercially available CTBN-modified bisphenol A type epoxy resins include: trade names "HyPoxRK84L", "HyPoxRK820", "HyPoxRA1340", "HyPoxRA16213", "HyPoxRA840", "HyPoxRA95" (all manufactured by HUNTSMAN Corporation), and "EPR-1630" (manufactured by ADEKA Corporation). Examples of commercially available CTBN-modified bisphenol F type epoxy resins include: trade names "HyPoxRF1320", "HyPoxRF1341", "HyPoxRF928", and "HyPoxRF933" (all manufactured by HUNTSMAN Corporation). Examples of commercially available CTBN-modified ethylene glycol epoxy resins include: "HyPoxRM20" and "HyPoxRM22" (manufactured by HUNTSMAN). Examples of commercially available other rubber-modified epoxy resins (b) include: "TSR-960" (manufactured by DIC Corporation), "EPR-1415-1", "EPR-2000", and "EPR-2007" (manufactured by ADEKA Corporation, NBR-modified epoxy resins).

[0050] The mass ratio of epoxy resin (a) to rubber-modified epoxy resin (b) [former:rear] is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40. If the ratio of epoxy resin (a) is 20 or more, the transferability of the thermosetting adhesive sheet is better. If the ratio of rubber-modified epoxy resin (b) is 20 or more, the peelability when peeling a release liner from the thermosetting adhesive sheet is better.

[0051] The content ratio of the thermosetting resin (especially epoxy resin) in the above-mentioned thermosetting adhesive sheet, relative to the total amount (100% by mass) of the thermosetting adhesive sheet, is preferably 60% by mass or more, more preferably 70% by mass or more. The above-mentioned content ratio is preferably 95% by mass or less, more preferably 90% by mass or less. Furthermore, the combined content ratio of epoxy resin (a) and rubber-modified epoxy resin (b) is preferably within the above-mentioned range.

[0052] (Epoxy Curing Agent) When the above-mentioned thermosetting adhesive sheet contains epoxy resin (especially epoxy resin (a) and rubber-modified epoxy resin (b)) as the above-mentioned thermosetting resin, it is preferable that the above-mentioned thermosetting adhesive sheet contains an epoxy curing agent. The above-mentioned epoxy curing agent promotes the polymerization of epoxy groups in the epoxy resin when heated. Only one type of epoxy curing agent may be used, or two or more types may be used.

[0053] As the above-mentioned epoxy curing agent, known or conventional curing agents that can be used for curing epoxy resins can be used, for example: urea compounds, amine compounds, acid anhydride compounds, acetylamine compounds, acetylhydrazine curing agents, imidazole curing agents, imidazoleline compounds, triphenylphosphine compounds, hot alkali generating agents, trihaloborane compounds, carboxylic acid compounds, phenolic resin compounds, polythiol curing agents, etc.

[0054] Examples of urea compounds include: 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), N'-phenyl-N,N-dimethylurea, 1,1'-(methyl-1,3-epenylphenyl)bis(3,3'-dimethylurea), 3-(4-chlorophenyl)-1,1-dimethylurea, N'-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N'-dimethylurea, 3,3'-[methylenebis-(1,3-epenylphenyl)]bis(1,1-dimethylurea), etc.

[0055] Examples of amine compounds include ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine, amine adducts thereof, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, etc.

[0056] As anhydride compounds, examples include: methyltetrahydrophthalic anhydride (4-methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, etc.), methylhexahydrophthalic anhydride (4-methylhexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, etc.), dodecenylsuccinic anhydride, methylneodymethylenetetrahydrophthalic anhydride, phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc. Phthalic anhydride, methylcyclohexene dicarboxylic anhydride, pyromellitic dianhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride, benzoic anhydride, methyl benzoic anhydride, hydrogenated methyl benzoic anhydride, 4-(4-methyl-3-pentenyl)tetrahydrophthalic anhydride, succinic anhydride, adipic anhydride, sebacic anhydride, dodecanoic anhydride, methylcyclohexene tetracarboxylic anhydride, vinyl ether-maleic anhydride copolymer, alkylstyrene-maleic anhydride copolymer, etc.

[0057] Examples of amide compounds include dicyandiamide and polyamide.

[0058] Examples of acehydrazine compounds include, for example, adipic acid acehydrazine and other acehydrazine compounds.

[0059] Examples of imidazole compounds include: 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-undecylimidazolium, 1-cyanoethyl-2-phenylimidazolium ontyltrimethylbenzene, 2,4-diamino-6-[2'-methylimidazolium] [Imidazolyl-(1')]-ethyl-symmetric triazole, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-symmetric triazole, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-symmetric triazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-symmetric triazole isocyanate adduct, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, etc.

[0060] Examples of imidazoline compounds include: methylimidazoline, 2-ethyl-4-methylimidazoline, ethylimidazoline, isopropylimidazoline, 2,4-dimethylimidazoline, phenylimidazoline, undecylimidazoline, heptadecanylimidazoline, 2-phenyl-4-methylimidazoline, etc.

[0061] Examples of triphenylphosphine compounds include: triphenylphosphine, tributylphosphine, tris(p-methylphenyl)phosphine, tris(nonylphenyl)phosphine, diphenyltolylphosphine, tetraphenylphosphine bromide, methyltriphenylphosphine, methyltriphenylphosphine chloride, methoxymethyltriphenylphosphine, benzyltriphenylphosphine chloride, etc. Triphenylphosphine compounds also include compounds possessing both a triphenylphosphine structure and a triphenylborane structure. Examples of such compounds include: tetraphenylphosphine tetraphenylborate, tetraphenylphosphine tetra-p-tolyl triborate, benzyltriphenylphosphine tetraphenylborate, triphenylphosphine triphenylborane, etc.

[0062] Examples of thermal alkali generating agents include: 1,8-diazabicyclo[5.4.0]undecene-7 (DBU) or its salts, 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) or its salts.

[0063] Examples of trihaloborane compounds include trichloroborane, etc.

[0064] The above-mentioned epoxy curing agent is preferably a latent curing agent. Latent curing agents function as curing agents through the heat during thermosetting, thus exhibiting excellent preservation stability, adhesion, and transferability of the thermosetting adhesive sheet in the pre-thermosetting state. Furthermore, the above-mentioned epoxy curing agent can also be a microencapsulated curing agent.

[0065] As the aforementioned epoxy curing agent, from the viewpoint of having higher adhesion after curing of the thermosetting adhesive sheet, a amide-based compound is preferred, and dicyandiamide is more preferred. Furthermore, as the aforementioned epoxy curing agent, it is preferable to contain a urea-based compound and / or an imidazole-based compound. More preferably, it contains a urea-based compound and / or an imidazole-based compound in addition to a amide-based compound. The urea-based compound and the imidazole-based compound (especially the urea-based compound) act as curing accelerators when the epoxy resin reacts with the amide-based compound, thus promoting the reaction rate.

[0066] The content of the epoxy curing agent in the above-mentioned thermosetting adhesive sheet is preferably 0.5 to 30 parts by mass relative to 100 parts by mass of the total amount of epoxy resin (especially 100 parts by mass of epoxy resin (a) and rubber-modified epoxy resin (b)), more preferably 1 to 20 parts by mass, further preferably 4 to 16 parts by mass, and particularly preferably 4.5 to 15 parts by mass. If the above content is within the above range, the adhesion of the thermosetting adhesive sheet after curing is higher.

[0067] The content of amide compounds in the above-mentioned thermosetting adhesive sheet is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the total amount of epoxy resin (especially 100 parts by mass of epoxy resin (a) and rubber-modified epoxy resin (b)), more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass. If the above content is within the above range, the adhesion of the thermosetting adhesive sheet after curing is higher.

[0068] The content of urea-based compounds and / or imidazole-based compounds in the above-mentioned thermosetting adhesive sheet is preferably 1 to 10 parts by mass relative to 100 parts by mass of the total epoxy resin (especially 100 parts by mass of the total epoxy resin (a) and rubber-modified epoxy resin (b)), more preferably 1.5 to 8 parts by mass, and even more preferably 2 to 7 parts by mass. If the above content is within the above range, the adhesion of the thermosetting adhesive sheet after curing is higher.

[0069] (Filler) Preferably, the above-mentioned thermosetting adhesive sheet contains filler. If filler is included, the modulus of elasticity G' of the thermosetting adhesive sheet at 80°C is more likely to be within the above-mentioned range. Only one type of filler may be used, or two or more types may be used. Examples of fillers include inorganic fillers and organic fillers.

[0070] Examples of materials constituting the aforementioned inorganic fillers include: aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, boron nitride, and silicon dioxide (crystalline silicon dioxide, amorphous silicon dioxide, etc.). Furthermore, examples of materials constituting the aforementioned inorganic fillers include: elemental metals or alloys such as aluminum, gold, silver, copper, and nickel; amorphous carbon black; and graphite.

[0071] In addition to the above-mentioned constituent materials, other inorganic fillers may also be listed as: mica, talc, kaolin, silica, feldspar, diorite, chlorite, bentonite, montmorillonite, dolomite, quartz, diaspore, hollow ceramic beads, hollow glass beads, glass beads, etc.

[0072] Examples of materials that constitute the above-mentioned organic filler include: polymethyl methacrylate (PMMA), polyimide, polyamide-imide, polyetheretherketone, polyether-imide, polyester-imide, etc.

[0073] The shape of the above-mentioned filler is not particularly limited and can have various shapes such as spherical, plate-like (scale-like), dendritic, fibrous, and amorphous (polyhedral).

[0074] As the above-mentioned filler, inorganic filler is preferred, and silicon dioxide filler is more preferred.

[0075] Silica filler can also undergo surface treatments such as hydrophobic treatment. Examples of treatment agents used for hydrophobic treatment include: methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane, methyltrialkoxysilane, dimethyldialkoxysilane, trimethylalkoxysilane, ethyltrichlorosilane, propyltrichlorosilane, hexyltrichlorosilane, long-chain alkyltrichlorosilane, ethyltrialkoxysilane, propyltrialkoxysilane, hexyltrialkoxysilane, long-chain alkyltrialkoxysilane, methacryloxysilane, fluoroalkylsilane, perfluoroalkylsilane, and other organosilyl compounds; dimethylpolysiloxane (silicone oil), methylphenylpolysiloxane, methylhydropolysiloxane, amino-modified silicone, and other silicone compounds.

[0076] The average particle size of the filler is preferably 50 nm or less, and more preferably 40 nm or less. If the average particle size is 50 nm or less, it is less likely for adhesive overflow to occur. The average particle size of the filler is preferably 7 nm or more, and more preferably 10 nm or more. If the average particle size is 7 nm or more, the bulk density is higher and the workability is excellent. Furthermore, the average particle size of the inorganic filler can be determined, for example, using a photometric particle size analyzer (e.g., trade name "LA-910", manufactured by Horiba Manufacturing Co., Ltd.).

[0077] The specific surface area of ​​the filler is preferably 30 m² / g or more, and more preferably 100 m² / g or more. If the specific surface area is 30 m² / g or more, it is more difficult for adhesive overflow to occur. From the viewpoint of selecting particles with higher bulk density and better workability, the specific surface area of ​​the filler is preferably 500 m² / g or less, and more preferably 350 m² / g or less.

[0078] The specific surface area of ​​the filler in each 100g of the above-mentioned thermosetting adhesive sheet is preferably 600 to 6000 m2, more preferably 800 to 5000 m2. If the specific surface area is 600 m2 or more, it is more difficult for adhesive to overflow. If the specific surface area is less than 6000 m2, it has excellent conformability to the unevenness of the bonded body and excellent shear adhesion.

[0079] The content of the filler in the above-mentioned thermosetting adhesive sheet is preferably 5 to 40 parts by mass relative to 100 parts by mass of the total amount of epoxy resin (especially 100 parts by mass of epoxy resin (a) and rubber-modified epoxy resin (b)), more preferably 6 to 35 parts by mass, and even more preferably 8 to 30 parts by mass. If the above content is 5 parts by mass or more, the elastic modulus G' of the thermosetting adhesive sheet at 80°C can be increased, and adhesive overflow can be further suppressed. If the above content is 40 parts by mass or less, the transferability of the thermosetting adhesive sheet is better.

[0080] The above-mentioned thermosetting adhesive sheet may also contain a colorant. The colorant may be a pigment or a dye. Examples of colorants include black, cyan, magenta, and yellow colorants. The colorant may be only one type or may contain two or more types. The ratio of the colorant in the above-mentioned thermosetting adhesive sheet to the total amount (100% by mass) of the above-mentioned thermosetting adhesive sheet is preferably 0.05 to 5% by mass, more preferably 0.1 to 2% by mass.

[0081] Examples of black colorants include: carbon black, carbon nanotubes, graphite (lead black), copper oxide, manganese dioxide, azo pigments such as iminoazo black, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite, magnetite, chromium oxide, iron oxide, molybdenum disulfide, complex oxide black pigments, anthraquinone organic black dyes, and azo organic black dyes. Examples of carbon black include: furnace black, chimney black, acetylene black, thermal black, and lamp black. Examples of black colorants include: CI Solvent Black 3, CI Solvent Black 7, CI Solvent Black 22, CI Solvent Black 27, CI Solvent Black 29, CI Solvent Black 34, CI Solvent Black 43, CI Solvent Black 70; CI Direct Black 17, CI Direct Black 19, CI Direct Black 22, CI Direct Black 32, CI Direct Black 38, CI Direct Black 51, CI Direct Black 71; CI Acid Black 1, CI Acid Black 2, CI Acid Black 24, CI Acid Black 26, CI Acid Black 31, CI Acid Black 48, CI Acid Black 52, CI Acid Black 107, CI Acid Black 109, CI Acid Black 110, CI Acid Black 119, CI Acid Black 154; CI Dispersion Black 1, CI Dispersion Black 3, CI Dispersion Black 10, CI Dispersion Black 24; CI Pigment Black 1, CI Pigment Black 7, etc.

[0082] As cyan colorants, examples include: CI Solvent Blue 25, CI Solvent Blue 36, CI Solvent Blue 60, CI Solvent Blue 70, CI Solvent Blue 93, CI Solvent Blue 95; CI Acid Blue 6, CI Acid Blue 45; CI Pigment Blue 1, CI Pigment Blue 2, CI Pigment Blue 3, CI Pigment Blue 15, CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4, CI Pigment Blue 15:5, CI Pigment Blue 15:6, CI Pigment Blue 16, CI Pigment Blue 17, CI Pigment Blue 17:1, CI Pigment Blue 18, CI Pigment Blue 22, CI Pigment Blue 25, CI Pigment Blue 56, CI Pigment Blue 60, CI Pigment Blue 63, CI Pigment Blue 65, CI Pigment Blue 66; CI Vat Blue 4; CI Vat Blue 60, CI Pigment Green 7, etc.

[0083] Examples of carmine-based colorants include: CI Solvent Red 1, CI Solvent Red 3, CI Solvent Red 8, CI Solvent Red 23, CI Solvent Red 24, CI Solvent Red 25, CI Solvent Red 27, CI Solvent Red 30, CI Solvent Red 49, CI Solvent Red 52, CI Solvent Red 58, CI Solvent Red 63, CI Solvent Red 81, CI Solvent Red 82, CI Solvent Red 83, CI Solvent Red 84, CI Solvent Red 100, CI Solvent Red 109, CI Solvent Red 111, CI Solvent Red 121, CI Solvent Red 122; CI Disperse Red 9; CI Solvent Violet 8, CI Solvent Violet 13, CI Solvent Violet 14, CI Solvent Violet 21, CI Solvent Violet 27; CI Disperse Violet 1; CI Basic Red 1. CI Basic Red 2, CI Basic Red 9, CI Basic Red 12, CI Basic Red 13, CI Basic Red 14, CI Basic Red 15, CI Basic Red 17, CI Basic Red 18, CI Basic Red 22, CI Basic Red 23, CI Basic Red 24, CI Basic Red 27, CI Basic Red 29, CI Basic Red 32, CI Basic Red 34, CI Basic Red 35, CI Basic Red 36, CI Basic Red 37, CI Basic Red 38, CI Basic Red 39, CI Basic Red 40; CI Basic Violet 1, CI Basic Violet 3, CI Basic Violet 7, CI Basic Violet 10, CI Basic Violet 14, CI Basic Violet 15, CI Basic Violet 21, CI Basic Violet 25, CI Basic Violet 26, CI Basic Violet 27, CI Basic Violet 28, etc. Furthermore, examples of carmine-based colorants include: CI Pigment Red 1, CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 4, CI Pigment Red 5, CI Pigment Red 6, CI Pigment Red 7, CI Pigment Red 8, CI Pigment Red 9, CI Pigment Red 10, CI Pigment Red 11, CI Pigment Red 12, CI Pigment Red 13, CI Pigment Red 14, CI Pigment Red 15, CI Pigment Red 16, CI Pigment Red 17, CI Pigment Red 18, CI Pigment Red 19, CI Pigment Red 21, CI Pigment Red 22, CI Pigment Red 23, CI Pigment Red 30, CI Pigment Red 31, CI Pigment Red 32, CI Pigment Red 37, CI Pigment Red 38, CI Pigment Red 39, CI Pigment Red 40, CI Pigment Red 41, CI Pigment Red 42, CI Pigment Red 48:1, CI Pigment Red 48:2, CI Pigment Red 48:3, CI Pigment Red 48:4, CI...Pigment Red 49, CI Pigment Red 49:1, CI Pigment Red 50, CI Pigment Red 51, CI Pigment Red 52, CI Pigment Red 52:2, CI Pigment Red 53:1, CI Pigment Red 54, CI Pigment Red 55, CI Pigment Red 56, CI Pigment Red 57:1, CI Pigment Red 58, CI Pigment Red 60, CI Pigment Red 60:1, CI Pigment Red 63, CI Pigment Red 63:1, CI Pigment Red 63:2, CI Pigment Red 64, CI Pigment Red 64:1, CI Pigment Red 67, CI Pigment Red 68, CI Pigment Red 81 CI Pigment Red 83, CI Pigment Red 87, CI Pigment Red 88, CI Pigment Red 89, CI Pigment Red 90, CI Pigment Red 92, CI Pigment Red 101, CI Pigment Red 104, CI Pigment Red 105, CI Pigment Red 106, CI Pigment Red 108, CI Pigment Red 112, CI Pigment Red 114, CI Pigment Red 122, CI Pigment Red 123, CI Pigment Red 139, CI Pigment Red 144, CI Pigment Red 146, CI Pigment Red 147, CI Pigment Red 149, CI Pigment Red 150, CI Pigment Red 151, CI Pigment Red 163, CI Pigment Red 166, CI Pigment Red 168, CI Pigment Red 170, CI Pigment Red 171, CI Pigment Red 172, CI Pigment Red 175, CI Pigment Red 176, CI Pigment Red 177, CI Pigment Red 178, CI Pigment Red 179, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 187, CI Pigment Red 190, CI Pigment Red 193, CI Pigment Red 202, CI Pigment Red 206, CI Pigment Red 207, CI Pigment Red 209, CI Pigment Red CI Pigment Red 219, CI Pigment Red 222, CI Pigment Red 224, CI Pigment Red 238, CI Pigment Red 245; CI Pigment Violet 3, CI Pigment Violet 9, CI Pigment Violet 19, CI Pigment Violet 23, CI Pigment Violet 31, CI Pigment Violet 32, CI Pigment Violet 33, CI Pigment Violet 36, CI Pigment Violet 38, CI Pigment Violet 43, CI Pigment Violet 50; CI Reduce Red 1, CI Reduce Red 2, CI Reduce Red 10, CI Reduce Red 13, CI Reduce Red 15, CI Reduce Red 23, CI Reduce Red 29, CI Reduce Red 35, etc.

[0084] Examples of yellow colorants include: CI Solvent Yellow 19, CI Solvent Yellow 44, CI Solvent Yellow 77, CI Solvent Yellow 79, CI Solvent Yellow 81, CI Solvent Yellow 82, CI Solvent Yellow 93, CI Solvent Yellow 98, CI Solvent Yellow 103, CI Solvent Yellow 104, CI Solvent Yellow 112, CI Solvent Yellow 162; CI Pigment Orange 31, CI Pigment Orange 43; CI Pigment Yellow 1, CI Pigment Yellow 2, CI Pigment Yellow 3, CI Pigment Yellow 4, CI Pigment Yellow 5 CI Pigment Yellow 6, CI Pigment Yellow 7, CI Pigment Yellow 10, CI Pigment Yellow 11, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 15, CI Pigment Yellow 16, CI Pigment Yellow 17, CI Pigment Yellow 23, CI Pigment Yellow 24, CI Pigment Yellow 34, CI Pigment Yellow 35, CI Pigment Yellow 37, CI Pigment Yellow 42, CI Pigment Yellow 53, CI Pigment Yellow 55, CI Pigment Yellow 65, CI Pigment Yellow 73, CI Pigment Yellow 74, CI Pigment Yellow 75, CI Pigment Yellow; 81, CI Pigment Yellow; 83, CI Pigment Yellow; 93, CI Pigment Yellow; 94, CI Pigment Yellow; 95, CI Pigment Yellow; 97, CI Pigment Yellow; 98, CI Pigment Yellow; 100, CI Pigment Yellow; 101, CI Pigment Yellow; 104, CI Pigment Yellow; 108, CI Pigment Yellow; 109, CI Pigment Yellow; 110, CI Pigment Yellow; 113, CI Pigment Yellow; 114, CI Pigment Yellow; 116, CI Pigment Yellow; 117, CI Pigment Yellow; 120, CI Pigment Yellow; 128, CI Pigment Yellow. Yellow 129, CI Pigment Yellow 133, CI Pigment Yellow 138, CI Pigment Yellow 139, CI Pigment Yellow 147, CI Pigment Yellow 150, CI Pigment Yellow 151, CI Pigment Yellow 153, CI Pigment Yellow 154, CI Pigment Yellow 155, CI Pigment Yellow 156, CI Pigment Yellow 167, CI Pigment Yellow 172, CI Pigment Yellow 173, CI Pigment Yellow 180, CI Pigment Yellow 185, CI Pigment Yellow 195; CI Reduced Yellow 1, CI Reduced Yellow 3, CI Reduced Yellow 20, etc.

[0085] The above-mentioned thermosetting adhesive sheet may also contain other components besides those described above, without impairing the effects of the present invention. Examples of such other components include: other curing accelerators, thermoplastic resins, adhesion-improving resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), anti-aging agents, antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, flame retardants, silane coupling agents, ion scavengers, foils, etc. Only one of the above-mentioned other components may be used, or two or more may be used.

[0086] There is no particular limitation on the thickness of the above-mentioned thermosetting adhesive sheet, but it is preferably 10 to 1000 μm, more preferably 30 to 750 μm, and even more preferably 50 to 500 μm. If the thickness is 10 μm or more, the adhesion of the above-mentioned thermosetting adhesive sheet when used for bonding components is even better.

[0087] The above-mentioned thermosetting adhesive sheet is sandwiched between two AL alloy A5052 sheets whose bonding portions have been ground with 100-grit sandpaper. After the two bonding surfaces are bonded together and thermosetting, the shear adhesion force measured under the conditions of a tensile speed of 1.3 mm / min and a peel angle of 0° is preferably 1 MPa or more, more preferably 5 MPa or more, and more preferably 10 MPa or more. If the above-mentioned shear adhesion force is 1 MPa or more, the adhesion between the components is excellent.

[0088] The thermosetting adhesive sheet of the present invention is preferably used for bonding components to each other. Since the thermosetting adhesive sheet exhibits excellent adhesion to metals, it is preferably used for bonding metal components. Furthermore, it is preferably used for bonding metal components to each other. Moreover, the thermosetting resin sheet of the present invention also exhibits excellent adhesion to components made of dissimilar materials. Therefore, the thermosetting adhesive sheet of the present invention is also preferably used for bonding metal components to fiber-reinforced resin components. Examples of the reinforcing fibers include known or conventional reinforcing fibers such as carbon fiber, glass fiber, aromatic polyamide fiber, boron fiber, graphite fiber, silicon carbide fiber, high-strength polyethylene fiber, tungsten carbide fiber, and poly(p-phenylene benzodiazepine) fiber (PBO fiber).

[0089] The aforementioned thermosetting adhesive sheet may also have a release liner (release film) attached to its surface (adhesive surface) before use. Furthermore, each adhesive surface of the aforementioned thermosetting adhesive sheet may be protected by two release liners, or by a single release liner with release surfaces on both sides, wound into a roll (wound body). The release liner serves as a protective material for the adhesive sheet and is peeled off when attached to the substrate. Alternatively, a release liner may not be required.

[0090] As the release liner described above, conventional release paper or the like can be used, without particular limitation. Examples include: a substrate having a release treatment layer, a low-adhesion substrate containing a fluoropolymer, or a low-adhesion substrate containing a non-polar polymer. Examples of substrates having the release treatment layer include: plastic films or papers that have undergone surface treatment with silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide release agents. Examples of fluoropolymers in low-adhesion substrates containing the aforementioned fluoropolymers include: polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and chlorofluoroethylene-vinylidene fluoride copolymer. Examples of non-polar polymers include: olefin resins (e.g., polyethylene, polypropylene). The release liner can be formed by known or conventional methods. The thickness of the release liner is also not particularly limited.

[0091] The above-mentioned thermosetting adhesive sheet can be manufactured by coating (applying) an adhesive composition for forming the adhesive sheet onto a release liner, and drying and curing the resulting adhesive composition layer as needed. The above-mentioned adhesive composition can be prepared by dissolving and dispersing the above-mentioned components such as epoxy resin (a), rubber-modified epoxy resin (b), the above-mentioned epoxy curing agent, and the above-mentioned filler in a solvent such as an organic solvent and mixing them together.

[0092] When peeling a release liner adhered to the adhesive surface, the thermosetting adhesive sheet of the present invention easily peels the release liner from the adhesive surface, exhibiting excellent operability and minimizing adhesive spillage. Therefore, for example, when peeling a release liner from both adhesive surfaces of the thermosetting adhesive sheet while it is protected by the release liner, no so-called "adhesive separation" occurs, and the release liner can be peeled off without damaging the adhesive sheet interface. Furthermore, when one adhesive surface of the thermosetting double-sided adhesive sheet is adhered to a component, and then a release liner adhered to the other adhesive surface is peeled off, the adhesive sheet exhibits excellent transferability, and the adhesive sheet will not peel off from the adhered component along with the release liner, allowing the release liner to be easily peeled off from the adhesive surface of the adhesive sheet. Moreover, after adhering the thermosetting adhesive sheet of the present invention to the substrate, heating it to harden the adhesive sheet firmly bonds it to the component. When components that are to be bonded are joined together by a thermosetting adhesive sheet, or when the thermosetting adhesive sheet is heated and hardened, the adhesive in the adhesive sheet is unlikely to leak out between the components due to pressure or heat. [Example]

[0093] Hereinafter, the present invention will be described in more detail by way of example, but the present invention is not limited by these examples. Furthermore, the composition of each component constituting the adhesive sheet in the examples and comparative examples is shown in the table. In the table, the units for each value representing the composition of the adhesive sheet are relative "parts by mass" in the adhesive sheet.

[0094] Example 1 Methyl ethyl ketone (MEK) was added to a rubber-modified epoxy resin (trade name "HyPoxRK84L", manufactured by HUNTSMAN) at a solid content ratio of 50 wt%, and the mixture was stirred thoroughly to obtain a rubber-modified epoxy resin solution. Subsequently, 80 parts by weight of the above-mentioned rubber-modified epoxy resin solution (40 parts by weight of rubber-modified epoxy resin), 60 parts by weight of bisphenol A type epoxy resin (trade name "jER-834", manufactured by Mitsubishi Chemical Co., Ltd.), 5 parts by weight of silica filler (trade name "Aerosil RY-200", manufactured by Aerosil Co., Ltd., Japan), 5 parts by weight of dicyandiamide-based curing agent (trade name "Omicure DDA-50", manufactured by HUNTSMAN Co., Ltd.), and 2 parts by weight of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) (manufactured by Tokyo Chemical Industries Co., Ltd.) were mixed and added to MEK in a solids ratio of 45 wt%. Subsequently, the adhesive composition was prepared by stirring at 2000 rpm for 1 minute using a high-speed mixer (trade name "Uniform Disperser", manufactured by PRIMIX Corporation), and then defoaming at 2000 rpm for 1 minute using a planetary mixer (trade name "Defoaming Mixer Taro", manufactured by Thinky Co., Ltd.).

[0095] Next, using a dressing applicator, the adhesive composition described above is applied to the release-treated surface of a 75 μm thick PET release film (second release film) having a release-treated surface, with a thickness of 0.1 mm when dried, to form an adhesive composition layer. Then, the solvent is dried by heating at 60°C for 10 minutes to form an adhesive layer. Subsequently, the release-treated surface of a 38 μm thick PET release film (first release film) having a release-treated surface is bonded to the adhesive layer to produce an adhesive sheet.

[0096] Examples 2-18 and Comparative Examples 1-6 were prepared in the same manner as in Example 1, except that the types and amounts of various raw materials used to make the adhesive composition were changed as shown in Tables 1 and 2.

[0097] The various raw materials shown in Tables 1 and 2 are as follows. (Epoxy Resin (a)) jER-828: Trade name "jER-828", room temperature liquid bisphenol A type epoxy resin, epoxy equivalent 184-194 g / eq, manufactured by Mitsubishi Chemical Co., Ltd. jER-834: Trade name "jER-834", semi-solid bisphenol A type epoxy resin, epoxy equivalent 230-270 g / eq, manufactured by Mitsubishi Chemical Co., Ltd. jER-1001: Trade name "jER-1001", solid bisphenol A type epoxy resin, epoxy equivalent 450-500 g / eq, manufactured by Mitsubishi Chemical Co., Ltd. jER-872: Trade name "jER-872", semi-solid dimer acid modified epoxy resin, epoxy equivalent 600-700 g / eq, manufactured by Mitsubishi Chemical Co., Ltd. Chemical Co., Ltd. manufactures jER-157S65B80: Trade name "jER-157S65B80", a solution type of solid special phenolic varnish epoxy resin, with an epoxy equivalent of 200-220 g / eq. Mitsubishi Chemical Co., Ltd. manufactures jER-YX7105: Trade name "jER-YX7105", a room-temperature liquid ultra-flexible epoxy resin, with an epoxy equivalent of 440-520 g / eq. Mitsubishi Chemical Co., Ltd. manufactures (rubber-modified epoxy resin (b)) EPR-1630: Trade name "EPR-1630", an epoxy resin formed by reacting epoxy resin with CTBN, with an epoxy equivalent of 900 g / eq. ADEKA Co., Ltd. manufactures HyPoxRK84L: Trade name "HyPoxRK84L", an epoxy resin formed by reacting bisphenol A type epoxy resin with CTBN, with an epoxy equivalent of 1250-1500 g / eq. g / eq, manufactured by HUNTSMAN (epoxy curing agent) Omicure DDA-50: trade name "Omicure DDA-50", dicyandiamide, manufactured by HUNTSMAN DCMU: 3-(3,4-dichlorophenyl)-1,1-dimethylurea, manufactured by Tokyo Chemical Products Co., Ltd. Omicure U-24M: trade name "Omicure U-24M", 1,1'-(4-methyl-1,3-epoxyphenyl)bis(3,3'-dimethylurea), manufactured by HUNTSMAN 2PHZ-PW: trade name "2PHZ-PW", 2-phenyl-4,5-Dihydroxymethylimidazolium, manufactured by Shikoku Chemical Industry Co., Ltd. (filler); Aerosil RY-50: trade name "Aerosil RY-50", hydrophobic treated fumigated silica, specific surface area 35-65 m² / g, average particle size 40 nm, manufactured by Aerosil Co., Ltd., Japan; Aerosil RY-200: trade name "Aerosil RY-200", hydrophobic treated fumigated silica, specific surface area 175-225 m² / g, average particle size 12 nm, manufactured by Aerosil Co., Ltd., Japan.

[0098] <Evaluation> The adhesive sheets obtained in the Examples and Comparative Examples were evaluated as follows. The results are shown in the table.

[0099] (1) Elastic modulus G' The adhesive layer of the adhesive sheet prepared in the examples and comparative examples was laminated until the thickness was 1 mm or more, and then cut into Φ8 mm. Dynamic viscoelasticity was measured using a rheometer (trade name "ARES G2", manufactured by TA Instruments) at a frequency of 1 Hz, a heating rate of 5°C / min, and a measurement temperature of 0 to 100°C. During the measurement, if the elastic modulus G' was below 1 MPa, the measurement was stopped even at 100°C. Furthermore, if the temperature at which the elastic modulus G' became below 1 MPa was 80°C or below, the elastic modulus G' at 80°C was recorded as below 1 MPa. The elastic modulus G' at 20°C and 80°C was measured as described above.

[0100] (2) Adhesion Separation The adhesive sheet prepared in the examples and comparative examples was cut into 10 mm wide × 50 mm long. The release film was peeled off from the end at a speed of 10 mm / min. The case where adhesive residue remained on only one release film was evaluated as "0", and the case where adhesive residue remained on both release films was evaluated as "×".

[0101] (3) Transferability The adhesive sheets prepared in the examples and comparative examples were cut into pieces with a width of 10 mm and a length of 50 mm. SUS304BA washed with ethyl acetate was used as the substrate. The first release liner of the cut adhesive sheet was peeled off, and the adhesive side was attached to the substrate. After standing at room temperature for 5 minutes, when the second release liner was peeled off, the situation where the adhesive residue was on the substrate was evaluated as "0", and the situation where the adhesive residue was on the second release liner or on both the substrate and the second release liner was evaluated as "×".

[0102] (4) Observation of adhesive overflow The test piece prepared in the above shear adhesion test. Observe the amount of adhesive overflowing between the two bonded objects. The case where the overflowed adhesive is less than 1 mm is evaluated as "0", the case where it is more than 1 mm but less than 2 mm is evaluated as "△", and the case where it is more than 2 mm is evaluated as "×".

[0103] (5) The basic operation of shear adhesion was performed based on JIS K6850:1999. Specifically, firstly, AL alloy A5052 with a width of 25 mm × length of 100 mm × thickness of 1.6 mm was ground three times with 100 grit sandpaper in the length direction at 45° and 135°. The ground surface was cleaned with ethyl acetate and air-dried for 30 minutes to obtain the substrate. On the other hand, the adhesive sheet prepared in the examples and comparative examples was cut into pieces with a width of 25 mm × length of 12.5 mm. The first release film of the cut adhesive sheet was peeled off and the adhesive surface was attached to the substrate. Then, the second release film was peeled off and attached to another substrate. When peeling off the second release film, without transferring the adhesive sheet, lamination was performed at 60°C for 10 seconds to perform the transfer. The two substrates were temporarily fixed at about 2 to 7 kPa. The adhesive sheet was heated in an oven at 150°C for 1 hour under a temporarily fixed condition to harden it. After cooling, the temporary fixation was removed to prepare a test piece. The two ends of the obtained test piece were fixed 25 mm apart with the clamps of a tensile testing machine. The tester was moved at a speed of 1.3 mm / min until the test piece broke. The maximum stress was taken as the shear adhesion force.

[0104] [Table 1] (Table 1) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Epoxy resin (a) jER-828 - - - - - - - - - - - - jER-834 60 60 60 60 60 20 40 80 60 60 - 60 jER-1001 - - - - - - - - - - 60 - jER-872 - - - - - - - - - - - - jER-157S65B80 - - - - - - - - - - - - jER-YX7105 - - - - - - - - - - - - Rubber-modified epoxy resin (b) EPR-1630 - - - - - - - - - - - - HyPoxRK84L 40 40 40 40 40 80 60 20 40 40 40 40 Epoxy hardener Omicure DDA-50 5 5 5 5 5 5 5 5 5 5 5 10 DCMU 2 2 2 2 2 2 2 2 2 2 2 2 Omicure U-24M - - - - - - - - - - - - 2PHZ-PW - - - - - - - - - - - - filler Aerosil RY-50 - - - - - - - - 25 35 - - Aerosil RY-200 5 10 15 25 35 10 7 10 - - 7 7 The specific surface area of ​​the filler per 100 g of bonded sheet [m 2 ] 893 1709 2459 3788 4930 1709 1228 1709 947 1232 1228 1176 Elastic modulus G' [kPa] 20℃ 154.8 296.9 331.4 766.7 2524.0 1881.8 625.1 164.1 274.6 489.4 2984.8 227.6 80℃ 4.3 25.3 105.5 243.7 422.7 29.9 8.2 45.3 11.3 27.4 14.8 10.8 Operability Adhesion Separation 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 Transferability 〇 〇 〇 〇 △ △ 〇 〇 〇 〇 △ 〇 Paste overflow △ 〇 〇 〇 〇 〇 △ 〇 〇 〇 〇 〇 Shear adhesion force [MPa] 20.6 17.7 15.8 10.6 5.8 16.6 20.8 16.0 18.9 17.4 18.3 19.6

[0105] [Table 2] (Table 2) Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Epoxy resin (a) jER-828 - - - - - - - - - - 60 - jER-834 60 60 60 - - - 50 60 10 90 - 60 jER-1001 - - - - - - - - - - - - jER-872 - - - 60 - - - - - - - - jER-157S65B80 - - - - 60 - - - - - - - jER-YX7105 - - - - - 40 - - - - - - Rubber-modified epoxy resin (b) EPR-1630 - - - - - - - - - - - 40 HyPoxRK84L 40 40 40 40 40 60 50 40 90 10 40 - Epoxy hardener Omicure DDA-50 2.5 5 5 3.8 3.8 3.8 5 5 5 5 5 5 DCMU - - - - - - 2 2 2 2 2 2 Omicure U-24M 5 - 5 5 5 5 - - - - - - 2PHZ-PW - 2 - - - - - - - - - - filler Aerosil RY-50 - - - - - - - - - - - - Aerosil RY-200 7 7 9 7 7 7 - 3 10 10 7 10 The specific surface area of ​​the filler per 100 g of sheet material [m²] 2 ] 1223 1228 1435 1209 1209 1209 0 545 1709 1709 1228 1709 Elastic modulus G' [kPa] 20℃ 192.7 195.8 261.5 353.2 424.4 178.4 230.9 119.0 4591.2 104.6 131.2 64.0 80℃ 7.1 9.2 16.8 7.6 6.0 6.4 <1 <1 73.3 43.1 11.9 5.8 Operability Adhesion Separation 〇 〇 〇 〇 〇 〇 〇 × 〇 × × × Transferability 〇 〇 〇 〇 〇 〇 〇 〇 × 〇 〇 〇 Paste overflow △ △ 〇 〇 △ △ × × 〇 〇 〇 △ Shear adhesion force [MPa] 17.3 18.7 19.5 9.7 12.7 12.3 19.5 20.6 12.1 14.5 18.5 15.1

[0106] As shown in Tables 1 and 2, the thermosetting adhesive sheet of the present invention is evaluated as exhibiting excellent transferability and operability, without causing adhesion separation. Furthermore, no adhesive overflow occurs. On the other hand, in cases where the elastic modulus G' is lower at 80°C (Comparative Examples 1 and 2), paste overflow was confirmed. In cases where the elastic modulus G' is higher at 20°C (Comparative Example 3), poor transferability and poor operability are evaluated. In cases where the elastic modulus G' is lower at 20°C (Comparative Examples 2, 4-6), no adhesion separation occurs, but operability is poor. [Simplified Explanation of the Diagram]

[0027] Figure 1 is a cross-sectional schematic diagram of a thermosetting adhesive sheet according to one embodiment of the present invention.

Claims

1. A thermosetting adhesive sheet having an elastic modulus G' of 150-3000 kPa at 20°C and an elastic modulus G' of 1 kPa or more at 80°C, and containing epoxy resin (a) with an epoxy equivalent of 200-800 g / eq.

2. The thermosetting adhesive sheet as claimed in claim 1, further comprising rubber-modified epoxy resin (b).

3. The thermosetting adhesive sheet as claimed in claim 2, wherein the epoxy resin (a) is selected from one or more of the group consisting of bisphenol type epoxy resin, phenolic varnish type epoxy resin, and dimer acid modified epoxy resin.

4. The thermosetting adhesive sheet as requested in item 2 or 3, wherein the mass ratio of epoxy resin (a) to rubber-modified epoxy resin (b) is 20:80 to 80:

20.

5. The thermosetting adhesive sheet as claimed in item 2 or 3 contains 0.5 to 30 parts by weight of epoxy curing agent relative to 100 parts by weight of the total epoxy resin (a) and rubber-modified epoxy resin (b).

6. The thermosetting adhesive sheet as claimed in claim 5, wherein the epoxy curing agent contains dicyandiamide, and the content of dicyandiamide is 0.5 to 20 parts by weight relative to the total of 100 parts by weight of epoxy resin (a) and rubber-modified epoxy resin (b).

7. The thermosetting adhesive sheet of claim 5, wherein the epoxy curing agent contains urea compounds and / or imidazole compounds, and the content of the urea compounds and / or imidazole compounds is 1 to 10 parts by weight relative to the total 100 parts by weight of epoxy resin (a) and rubber-modified epoxy resin (b).

8. The thermosetting adhesive sheet, as requested in any of items 1 to 3, contains filler.

9. The thermosetting adhesive sheet as claimed in claim 8, wherein the average particle size of the filler is 7 to 50 nm.

10. The thermosetting adhesive sheet as claimed in claim 8, wherein the specific surface area of ​​the filler in 100 g of the thermosetting adhesive sheet is 600 to 6000 m2.

11. The thermosetting adhesive sheet of any one of claims 1 to 3 is used to bond together components in which at least one component is a metal component.

12. The thermosetting adhesive sheet of claim 11, used for bonding metal components to each other or metal components to fiber-reinforced resin components.

Images