Adhesive sheet

Abstract

The invention relates to an adhesive sheet with superior mobility to allow easy removal of the backing from the adhesive surface of the adhesive sheet when removing the backing, and with minimal spillage of the adhesive. The invention also relates to a method of producing multilayer sheets, such that the method produces with minimal spillage of the adhesive when forming multilayer sheets by bonding the parts together via the adhesive sheet. Adhesive sheet 1 has: an elastic modulus G' (A1) of 1 × 103 to 5 × 106 Pa at 20°C and an elastic modulus G' (A2) of 1 × 104 Pa or less at 80°C before active irradiation; an elastic modulus G' (B1) greater than the elastic modulus G' (A1) at 20°C and an elastic modulus G' (B2) of 1 × 103 Pa or greater at 80°C after active irradiation; and the elastic modulus E' is 1 × 108 to 1 × 1011 Pa at 20°C after thermal solidification.

Description

adhesive sheet

[0001] The present invention relates to an adhesive sheet.

[0002] In recent years, for example, to bond a metal member to another member, a thermosetting double-sided adhesive sheet that hardens when heated to exert adhesive strength and firmly bond the members together has been used. Known examples of such thermosetting adhesive sheets include adhesive sheets containing a thermosetting resin and a curing agent (see, for example, Patent Documents 1 to 3).

[0003] Double-sided adhesive sheets used to bond components together usually have release liners attached to both adhesive surfaces to protect the adhesive surfaces until use. When using the double-sided adhesive sheet, first one release liner is peeled off and the exposed adhesive surface is attached to one component, and then the other release liner is peeled off and the exposed adhesive surface is attached to the other component.

[0004] JP 2012-197427 A JP 2019-39005 A JP 7-157535 A

[0005] Although thermosetting adhesive sheets cure with heat and adhere firmly to a component, many are soft before heat curing. Therefore, when one adhesive surface of a double-sided adhesive sheet is bonded to a component and then an attempt is made to peel off a release liner bonded to the other adhesive surface, the release liner may not peel off from the adhesive surface of the adhesive sheet, and the adhesive sheet may peel off from the bonded component together with the release liner. In other words, the adhesive sheet may have poor transferability. For this reason, adhesive sheets are required to have excellent transferability, allowing the release liner to be easily peeled off from the adhesive surface.

[0006] Furthermore, after the thermosetting adhesive sheet is attached to a member as described above, it is heated to harden the adhesive sheet and firmly adhere it to the member. However, when the members that are adherends are attached 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 flow due to pressure or heat and squeeze out from between the members, i.e., glue squeezing may occur.

[0007] For this reason, thermosetting adhesive sheets are required to have excellent transferability so that the release liner can be easily peeled from the adhesive surface of the adhesive sheet when the release liner is peeled off, and to be less likely to cause the adhesive to squeeze out. Note that the adhesive sheets disclosed in Patent Documents 1 to 3 do not mention having all of these properties, and there is no disclosure of a thermosetting adhesive sheet having the properties satisfied by the thermosetting adhesive sheet of the present invention described below.

[0008] The present invention was conceived under these circumstances, and its object is to provide an adhesive sheet that allows the release liner to be easily peeled from the adhesive surface of the adhesive sheet when the release liner is peeled off, has excellent transferability, and is less likely to cause adhesive to extrude. Another object of the present invention is to provide a method for producing a laminate that is less likely to cause adhesive to extrude when components are bonded together via the adhesive sheet to produce the laminate.

[0009]

[0006] As a result of extensive research to achieve the above object, the present inventors have found that an adhesive sheet in which the modulus of elasticity G' at 20°C and the modulus of elasticity G' at 80°C before and after irradiation with active energy rays, and the modulus of elasticity E' at 20°C after heat curing are each within a specific range, allows the release liner laminated to the adhesive surface to be easily peeled from the adhesive surface, has excellent transferability, and is less likely to produce adhesive extrusion. The present invention was completed based on these findings.

[0010] That is, in the present invention, the elastic modulus G'(A1) at 20°C before irradiation with active energy rays is 1 x 10 ３ ~5 x 10 ６ Pa, the elastic modulus G' (A2) at 80°C is 1 x 10 ４After irradiation with active energy rays, the elastic modulus G'(B1) at 20°C is greater than the elastic modulus G'(A1), and the elastic modulus G'(B2) at 80°C is 1×10 ３ The elastic modulus E' at 20°C after heat curing is 1 x 10 ８ ~1 x 10 １１ An adhesive sheet is provided.

[0011] The adhesive sheet is used, for example, as follows: First, the release liner is peeled from one adhesive surface of the adhesive sheet, and the exposed adhesive surface is adhered to one adherend for close contact. Next, at least a portion of the adhesive sheet is cured by irradiation with active energy rays, and then the release liner is peeled from the other adhesive surface. Next, the other adherend is adhered to the other exposed adhesive surface, and the adhesive sheet is then heated to thermally cure. In this way, the adhesive sheet can be used to adhere adherends to each other.

[0012] The adhesive sheet of the present invention has an elastic modulus G'(A1) of 1×10 at 20° C. before irradiation with active energy rays. ３ When the modulus of elasticity G'(A1) is 5×10 Pa or more, the sheet has a suitable hardness at around room temperature and can function as a sheet when attached to an adherend. ６ When the elastic modulus G'(A2) at 80°C before irradiation with active energy rays is 1 x 10 Pa or less, the adhesive sheet can easily adhere to the adherend when one adhesive surface of the adhesive sheet is attached to the adherend. ４ By ensuring that the viscosity is 100 Pa or less, the composition has excellent conformability to the adherend during thermal curing, and excellent adhesiveness to the adherend.

[0013] Furthermore, the adhesive sheet has a modulus of elasticity G'(B1) at 20°C after irradiation with active energy rays that is greater than the modulus of elasticity G'(A1), and therefore exhibits excellent releasability and transferability when attempting to peel the other release liner from the adhesive sheet after irradiation with active energy rays. Furthermore, the modulus of elasticity G'(B2) at 80°C after irradiation with active energy rays is 1×10 ３By having a modulus of elasticity E' of 1 x 10 Pa or more, the adhesive has sufficient hardness before heat curing and when pressure or heat is applied, so the adhesive has low fluidity and is less likely to leak out from between components. ８ ~1 x 10 １１ By virtue of the viscosity being Pa, the adhesive has appropriate flexibility and excellent adhesiveness between adherends.

[0014] The elastic modulus G'(B1) at 20°C is 1 x 10 ３ Pa super 5×10 ８ When the elastic modulus at 20°C, G'(B1), is within the above range, the adhesive sheet has an appropriate hardness, and when the other release liner is peeled off after irradiation with active energy rays, the adhesive sheet has excellent transferability to the one adherend while easily peeling off the other release liner, resulting in even better transferability.

[0015] The present invention also provides an adhesive sheet (sometimes referred to as "adhesive sheet X") having the following region (A) and region (B) in the planar direction: Region (A): Elastic modulus G'(A1) at 20°C is 1 x 10 ３ ~5 x 10 ６ Pa, elastic modulus G' (A2) at 80°C is 1 x 10 ４ Region (B): The elastic modulus G'(B1) at 20°C is greater than the elastic modulus G'(A1), and the elastic modulus G'(B2) at 80°C is less than 1×10 ３ Area above Pa

[0016] The adhesive sheet of the present invention has the region (A) over the entire surface before irradiation with active energy rays. The adhesive sheet X having regions (A) and (B) can have the region (B) formed, for example, by irradiating a portion of the adhesive sheet of the present invention with active energy rays. When one surface of the adhesive sheet X is attached to an adherend and the other release liner is peeled from the adhesive sheet X, the presence of region (A) provides excellent release liner releasability. Furthermore, the presence of region (B) provides excellent adhesion to the adherend and excellent transferability in region (B). Furthermore, the elastic modulus G'(B2) at 80°C is 1×10 ３By having a region (B) where the modulus of elasticity is 1×10 Pa or more, the adhesive has sufficient hardness before thermal curing when pressure or heat is applied, so the adhesive has low fluidity and is less likely to leak out from between the components. ４ By having the region (A) where the modulus is not more than 1 Pa, the composition has excellent conformability to the adherend during thermal curing and excellent adhesiveness to the adherend.

[0017] The adhesive sheet X preferably has the region (B) at one end in the surface direction.

[0018] The adhesive sheet preferably contains an epoxy resin as a thermosetting component, and further preferably contains an epoxy resin (a) and a rubber-modified epoxy resin (b) having an epoxy equivalent of 200 to 800 g / eq.

[0019] The adhesive sheet preferably contains 0.5 to 30 parts by mass of an epoxy curing agent (c) per 100 parts by mass of the epoxy resin.

[0020] The adhesive sheet preferably contains a polyfunctional compound (d) having two or more reactive double bonds in the molecule.

[0021] The polyfunctional compound (d) preferably has a (meth)acryloyl group and / or a (meth)acrylamide group.

[0022] The adhesive sheet preferably contains 0.1 to 12 parts by mass of the polyfunctional compound (d) per 100 parts by mass of the epoxy resin.

[0023] The adhesive sheet preferably contains 0.1 to 5 parts by mass of a photopolymerization initiator (e) relative to 100 parts by mass of the epoxy resin.

[0024] The adhesive sheet is preferably used to bond members, at least one of which is made of metal.

[0025] The adhesive sheet is preferably used to bond metal members together or a metal member and a fiber-reinforced resin member.

[0026] The present invention also provides a method for producing a laminate in which a first adherend and a second adherend are bonded together via an adhesive sheet, the method comprising the steps of: irradiating an adhesive sheet, which is bonded to a first adherend, with active energy rays to a portion of its surface in the direction of the surface thereof and has active energy ray curability and thermosetting properties, thereby curing the adhesive; or irradiating an adhesive sheet, which is bonded to a first adherend, with active energy rays to a portion of its surface in the direction of the surface thereof, thereby curing the adhesive sheet, and then bonding the adhesive sheet to the first adherend; bonding a second adherend to the adhesive sheet; and heating the adhesive sheet to thermally cure the adhesive sheet.

[0027] At least one of the first adherend and the second adherend is preferably a metal member.

[0028] The combination of the first adherend and the second adherend is preferably a combination of a metal member and a metal member, or a combination of a metal member and a fiber-reinforced resin member.

[0029] The part in the plane direction is preferably one end in the plane direction.

[0030] The adhesive sheet of the present invention has excellent transferability, allowing the release liner to be easily peeled from the adhesive surface of the adhesive sheet when the release liner is peeled off, and is also less likely to produce adhesive extrusion. Furthermore, according to the method for producing a laminate of the present invention, adhesive extrusion is less likely to occur when components are bonded together via the adhesive sheet to produce a laminate.

[0031] It is a schematic cross-sectional view of an adhesive sheet according to one embodiment of the present invention. It is a flow chart showing a process of a method for producing a laminate according to one embodiment of the present invention. It is a flow chart showing another process of a method for producing a laminate according to one embodiment of the present invention.

[0032] [Adhesive Sheet] The adhesive sheet of the present invention is active energy ray-curable and thermosetting. The adhesive sheet is preferably a double-sided adhesive sheet, and more preferably a so-called "substrate-less" double-sided adhesive sheet that does not have a substrate. Substrate-less double-sided adhesive sheets are free from problems caused by using a substrate, such as interlayer fracture with the substrate, and also have excellent conformability to the adherend. The adhesive sheet may be used as a single layer to bond components together, or may be used as a laminate of adhesive sheets by stacking multiple layers together to bond components together. Alternatively, a substrate layer may be attached to the adhesive sheet to form a single-sided adhesive sheet.

[0033] Fig. 1 is a cross-sectional schematic diagram showing one embodiment of an adhesive sheet of the present invention. Adhesive sheet 1 shown in Fig. 1 is a double-sided adhesive sheet. Release liners 2 and 3 are attached to both adhesive surfaces of adhesive sheet 1, respectively.

[0034] The adhesive sheet is used, for example, as follows: First, the release liner is peeled from one adhesive surface of the adhesive sheet, and the exposed adhesive surface is adhered to one adherend for close contact. Next, at least a portion of the adhesive sheet is cured by irradiation with active energy rays, and then the release liner is peeled from the other adhesive surface. Next, the other adherend is adhered to the other exposed adhesive surface, and the adhesive sheet is then heated to thermally cure. In this way, the adhesive sheet can be used to adhere adherends to each other.

[0035] The adhesive sheet of the present invention has an elastic modulus G' at 20°C before irradiation with active energy rays (sometimes referred to as "elastic modulus G'(A1)") of 1 x 10 ３ ~5 x 10 ６ Pa, preferably 1×10 ４ ~3 x 10 ６ Pa, more preferably 5×10 ４ ~2 x 10 ６ The elastic modulus G'(A1) at 20°C before irradiation with active energy rays is 1 x 10 ３ When the modulus of elasticity G'(A1) at 20°C is 5×10 Pa or more, the sheet has a suitable hardness at around room temperature and can function as a sheet when attached to an adherend. ６By ensuring that the elastic modulus is 1 Pa or less, the adhesive sheet can easily adhere to the adherend when one adhesive surface of the adhesive sheet is attached to the adherend.

[0036] The adhesive sheet of the present invention has an elastic modulus G' at 80°C before irradiation with active energy rays (sometimes referred to as "elastic modulus G'(A2)") of 1 x 10 ４ Pa or less, preferably 8×10 ３ Pa or less, more preferably 5×10 ３ The elastic modulus G'(A2) at 80°C before irradiation with active energy rays is 1 x 10 ４ When the modulus of elasticity G'(A2) is 1 Pa or less, the composition has excellent conformability to the adherend during thermal curing and excellent adhesiveness to the adherend.

[0037] The adhesive sheet of the present invention has a modulus of elasticity G' at 20°C after irradiation with active energy rays (sometimes referred to as "modulus of elasticity G'(B1)") that is greater than the modulus of elasticity G'(A1). Since the modulus of elasticity G'(B1) at 20°C is greater than the modulus of elasticity G'(A1), the adhesive sheet has excellent releasability and transferability when attempting to peel the other release liner from the adhesive sheet after irradiation with active energy rays.

[0038] In the adhesive sheet of the present invention, the ratio of the elastic modulus G'(B1) to the elastic modulus G'(A1) [elastic modulus G'(B1) / elastic modulus G'(A1)] is preferably 1.5 or more, more preferably 5 or more, and even more preferably 10 or more. When this ratio is 1.5 or more, the adhesive sheet exhibits superior releasability and transferability when attempting to peel the other release liner from the adhesive sheet after irradiation with active energy rays. Furthermore, this ratio is, for example, 1000 or less, preferably 500 or less, and more preferably 300 or less. When this ratio is 1000 or less, the adhesive sheet exhibits superior adhesion to the adherend and transferability when attempting to peel the other release liner from the adhesive sheet after irradiation with active energy rays.

[0039] The elastic modulus G'(B1) at 20°C is 1 x 10 ３ Pa super 5×10 ８ Pa or less, and more preferably 1×10 ４ ~1 x 10８ Pa, more preferably 1×10 ５ ~7 x 10 ７ When the elastic modulus at 20°C, G'(B1), is within the above range, the adhesive sheet has an appropriate hardness, and when the other release liner is peeled off after irradiation with active energy rays, the adhesive sheet has excellent transferability to the one adherend while easily peeling off the other release liner, resulting in even better transferability.

[0040] The adhesive sheet of the present invention has an elastic modulus G' at 80°C after irradiation with active energy rays (sometimes referred to as "elastic modulus G'(B2)") of 1 x 10 ３ Pa or more, preferably 1.5×10 ３ Pa or more, more preferably 2×10 ３ The elastic modulus G'(B2) at 80°C after irradiation with active energy rays is 1 x 10 ３ By having a modulus of elasticity G' (B2) of 1×10 Pa or more, the adhesive has sufficient hardness before thermal curing when pressure or heat is applied, so the adhesive has low fluidity and is less likely to leak out from between the members. ６ Pa or less, preferably 1×10 ５ The elastic modulus G'(B2) is 1×10 Pa or less. ６ When the viscosity is 100 Pa or less, the adhesiveness to the adherend before thermal curing is excellent.

[0041] The adhesive sheet of the present invention has an elastic modulus E' of 1 x 10 at 20°C after heat curing. ８ ~1 x 10 １１ Pa, preferably 5×10 ８ ~1 x 10 １０ Pa, more preferably 7×10 ８ ~5 x 10 ９ When the elastic modulus E' at 20°C after heat curing is within the above range, the composition has appropriate flexibility and excellent adhesiveness between adherends.

[0042] The elastic modulus G' at 20°C and the elastic modulus G' at 80°C are the elastic moduli of the adhesive sheet before thermal curing, and the elastic modulus E' at 20°C is the elastic modulus of the adhesive sheet after thermal curing. The elastic moduli are determined as storage moduli at 20°C or 80°C by dynamic mechanical analysis (DMA).

[0043] In this specification, "before active energy ray irradiation" refers to a state in which the adhesive sheet has not been completely cured by active energy ray irradiation, but rather a state in which the adhesive sheet has active energy ray curability. That is, "before active energy ray irradiation" may be in either the A stage or the B stage. Furthermore, "before active energy ray irradiation" preferably refers to a state before the adhesive sheet is attached to the first adherend. Furthermore, "before thermal curing" in this specification refers to a state in which the adhesive sheet has not been subjected to a curing treatment or has been partially cured so that the reactivity is less than 50%. Specifically, the reactivity of the adhesive sheet is measured using a differential scanning calorimeter (DSC) to measure the heat release [J / g] when the target adhesive sheet (target object) and the target object heated to a temperature at which the target object can be thermally cured (heated object) are heated from 0°C to 300°C at a heating rate of 10°C / min. The heat release from the target object from 0°C to 300°C is defined as the "heat release from the target object," and the heat release from the heated object from 0°C to 300°C is defined as the "heat release after heating," and the reactivity can be calculated using the following formula: Reaction rate = Amount of heat generated after heating [J / g] ÷ Amount of heat generated from object [J / g] × 100

[0044] The adhesive sheet has the property of being cured by heat, and therefore preferably contains a thermosetting resin.

[0045] The thermosetting resin is a resin having a thermosetting functional group. Examples of the thermosetting resin include epoxy resin, phenol resin, amino resin, unsaturated polyester resin, polyurethane resin, silicone resin, thermosetting polyimide resin, melamine resin, and alkyd resin. The thermosetting resin may be used alone or in combination of two or more.

[0046] Examples of the epoxy resin include bisphenol-type epoxy resins, hydrogenated bisphenol-type epoxy resins, spirocyclic epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins, fluorene-type epoxy resins, terpene-type epoxy resins, glycidyl ether-type epoxy resins, glycidylamine-type epoxy resins, novolac-type epoxy resins, trishydroxyphenylmethane-type epoxy resins, tetraphenylolethane-type epoxy resins, hydantoin-type epoxy resins, trisglycidyl isocyanurate-type epoxy resins, etc. The epoxy resin may also be a modified epoxy resin such as a urethane-modified epoxy resin or a rubber-modified epoxy resin.

[0047] Examples of the bisphenol-type epoxy resins include bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, brominated bisphenol A-type epoxy resins, and bisphenol AF-type epoxy resins. Examples of the glycidyl ether-type epoxy resins include tris(glycidyloxyphenyl)methane and tetrakis(glycidyloxyphenyl)ethane. Examples of the glycidylamine-type epoxy resins include tetraglycidyldiaminodiphenylmethane. Examples of the novolac-type epoxy resins include cresol novolac-type epoxy resins, phenol novolac-type epoxy resins, α-naphthol novolac-type epoxy resins, brominated phenol novolac-type epoxy resins, and orthocresol novolac-type epoxy resins. Among these, bisphenol-type epoxy resins are preferred from the viewpoint of easy handling, and bisphenol A-type epoxy resins are more preferred.

[0048] Among the thermosetting resins, epoxy resins are preferred. The epoxy resin preferably contains an epoxy resin with an epoxy equivalent of 200 to 800 g / eq, and more preferably a rubber-modified epoxy resin. In this specification, the epoxy resin with an epoxy equivalent of 200 to 800 g / eq may be referred to as "epoxy resin (a)," and the rubber-modified epoxy resin may be referred to as "rubber-modified epoxy resin (b)." The inclusion of epoxy resin (a) provides an appropriate distance between crosslinking points in the epoxy resin (a), making it easier to achieve an adhesive sheet with an elastic modulus G' at 20°C within the above-mentioned range. Furthermore, the inclusion of rubber-modified epoxy resin (b) in addition to epoxy resin (a) toughens the adhesive sheet containing epoxy resin (a), allowing it to maintain its shape more stably. The epoxy resin (a) and the rubber-modified epoxy resin (b) may each be used singly or in combination of two or more.

[0049] The epoxy resin (a) and the rubber-modified epoxy resin (b) are different resins. For example, the epoxy resin (a) may be an epoxy resin other than the rubber-modified epoxy resin, and the epoxy equivalent of the rubber-modified epoxy resin (b) may be less than 200 g / eq or more than 800 g / eq.

[0050] (Epoxy Resin (a)) The epoxy equivalent of the epoxy resin (a) is 200 to 800 g / eq, preferably 200 to 500 g / eq, and more preferably 200 to 400 g / eq. When the epoxy equivalent is 200 g / eq or more, the adhesive sheet has an appropriate hardness, is easy to peel when the release liner is peeled off, and is less likely to cause the adhesive to squeeze out. When the epoxy equivalent is 800 g / eq or less, the adhesive sheet has an appropriate softness, has excellent adhesion to the adherend when one adhesive surface of the adhesive sheet is stuck to the adherend, and is excellent in transferability when the release liner stuck to the other adhesive surface is peeled off.

[0051] The epoxy resin (a) may be an epoxy resin that is solid at room temperature, an epoxy resin that is liquid at room temperature, or an epoxy resin that is semi-solid at room temperature. However, from the viewpoint of easily obtaining an adhesive sheet that has excellent transferability and is less likely to extrude, a semi-solid epoxy resin is preferred. Note that "semi-solid" refers to being solid at 20°C and liquid at 40°C. Furthermore, from the viewpoint of easily obtaining an adhesive sheet that has excellent transferability and is less likely to extrude, the epoxy resin (a) preferably has a softening point of 70°C or less. Furthermore, the epoxy resin (a) is preferably a semi-solid or an epoxy resin with a softening point of 70°C or less.

[0052] As the epoxy resin (a), from the viewpoints of ease of handling and availability, bisphenol type epoxy resins are preferred, and bisphenol A type epoxy resins are more preferred.

[0053] (Rubber-Modified Epoxy Resin (b)) The rubber-modified epoxy resin (b) contains a rubber component in an 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, terminal carboxy-modified butadiene-acrylonitrile copolymer rubber (CTBN), and styrene-butadiene elastomers. One type of rubber component may be used alone, or two or more types may be used. Of the rubber-modified epoxy resins (b), CTBN-modified epoxy resins are preferred from the viewpoint of being able to more sufficiently toughen the adhesive sheet.

[0054] Examples of the epoxy resin in the rubber-modified epoxy resin (b) include those mentioned above. Among them, bisphenol-type epoxy resins are preferred, and bisphenol A-type epoxy resins are more preferred.

[0055] The epoxy equivalent of the rubber-modified epoxy resin (b) is preferably 1000 to 2000 g / eq, and more preferably 1200 to 1800 g / eq. When the epoxy equivalent is within this range, the adhesive sheet is likely to have an elastic modulus G' at 20°C within the above range. Furthermore, when the epoxy equivalent is 1000 g / eq or more, the adhesive sheet has an appropriate hardness, is easily peeled from the release liner, and is less likely to exude adhesive.

[0056] Commercially available rubber-modified epoxy resins (b) can be used. Commercially available CTBN-modified bisphenol A epoxy resins include those under the trade names "HyPoxRK84L", "HyPoxRK820", "HyPoxRA1340", "HyPoxRA16213", "HyPoxRA840", and "HyPoxRA95" (all manufactured by HUNTSMAN), and "EPR-1630" (manufactured by ADEKA Corporation). Commercially available CTBN-modified bisphenol F epoxy resins include those under the trade names "HyPoxRF1320", "HyPoxRF1341", "HyPoxRF928", and "HyPoxRF933" (all manufactured by HUNTSMAN). Commercially available CTBN-modified glycol-type epoxy resins include those sold under the trade names "HyPox RM20" and "HyPox RM22" (both manufactured by HUNTSMAN). Other commercially available rubber-modified epoxy resins (b) include those sold under the trade names "TSR-960" (manufactured by DIC Corporation), "EPR-1415-1", "EPR-2000", and "EPR-2007" (all manufactured by ADEKA Corporation, NBR-modified epoxy resins).

[0057] The mass ratio of the epoxy resin (a) to the rubber-modified epoxy resin (b) [former:latter] is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40. When the proportion of the epoxy resin (a) is 20 or more, the transferability of the adhesive sheet is superior. When the proportion of the rubber-modified epoxy resin (b) is 20 or more, the releasability when peeling one of the release liners from the adhesive sheet is superior.

[0058] The content of the thermosetting resin (particularly the epoxy resin) in the adhesive sheet is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total amount (100% by mass) of the adhesive sheet. The content is preferably 95% by mass or less, more preferably 90% by mass or less. The combined content of the epoxy resin (a) and the rubber-modified epoxy resin (b) is preferably within the above range.

[0059] (Epoxy curing agent (c)) When the adhesive sheet contains an epoxy resin (particularly, an epoxy resin (a) and a rubber-modified epoxy resin (b)) as the thermosetting resin, the adhesive sheet preferably contains an epoxy curing agent (c). The epoxy curing agent (c) promotes polymerization of the epoxy groups in the epoxy resin when heated. Only one type of epoxy curing agent (c) may be used, or two or more types may be used.

[0060] As the epoxy curing agent (c), any known or conventional curing agent used for curing epoxy resins can be used, and examples thereof include urea-based compounds, amine-based compounds, acid anhydride-based compounds, amide-based compounds, hydrazide-based curing agents, imidazole-based curing agents, imidazoline-based compounds, triphenylphosphine-based compounds, thermal base generators, trihalogenborane-based compounds, carboxylic acid-based compounds, phenolic resin-based compounds, and polymercaptan-based curing agents.

[0061] Examples of urea compounds include 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), N'-phenyl-N,N-dimethylurea, 1,1'-(methyl-1,3-phenylene)bis(3,3'-dimethylurea), 3-(4-chlorophenyl)-1,1-dimethylurea, N'-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N'-dimethylurea, and 3,3'-[methylenebis-(1,3-phenylene)]bis(1,1-dimethylurea).

[0062] Examples of the amine compounds include ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine, amine adducts thereof, metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0063] Examples of acid anhydride compounds include methyltetrahydrophthalic anhydride (4-methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, etc.), methylhexahydrophthalic anhydride (4-methylhexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, etc.), dodecenyl succinic anhydride, methylendomethylenetetrahydrophthalic anhydride, phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylcyclohexene dicarboxylic acid, and the like. carboxylic anhydride, pyromellitic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride, nadic anhydride, methyl nadic anhydride, hydrogenated methyl nadic anhydride, 4-(4-methyl-3-pentenyl)tetrahydrophthalic anhydride, succinic anhydride, adipic anhydride, sebacic anhydride, dodecanedioic anhydride, methylcyclohexene tetracarboxylic anhydride, vinyl ether-maleic anhydride copolymer, alkylstyrene-maleic anhydride copolymer, and the like.

[0064] Examples of the amide compounds include dicyandiamide and polyamide.

[0065] Examples of the hydrazide compounds include dihydrazides such as adipic acid dihydrazide.

[0066] Examples of imidazole compounds include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and the like.

[0067] Examples of imidazoline compounds include methylimidazoline, 2-ethyl-4-methylimidazoline, ethylimidazoline, isopropylimidazoline, 2,4-dimethylimidazoline, phenylimidazoline, undecylimidazoline, heptadecylimidazoline, and 2-phenyl-4-methylimidazoline.

[0068] Examples of triphenylphosphine compounds include triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, tri(nonylphenyl)phosphine, diphenyltolylphosphine, tetraphenylphosphonium bromide, methyltriphenylphosphonium, methyltriphenylphosphonium chloride, methoxymethyltriphenylphosphonium, and benzyltriphenylphosphonium chloride. Triphenylphosphine compounds also include compounds having both a triphenylphosphine structure and a triphenylborane structure. Examples of such compounds include tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-triborate, benzyltriphenylphosphonium tetraphenylborate, and triphenylphosphinetriphenylborane.

[0069] Examples of the thermal base generator include 1,8-diazabicyclo[5.4.0]undecene-7 (DBU) or a salt thereof, and 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) or a salt thereof.

[0070] Examples of trihalogen borane compounds include trichloroborane.

[0071] The epoxy curing agent (c) is preferably a latent curing agent. Latent curing agents exert their curing action due to the heat generated during thermal curing, and therefore the adhesive sheet has excellent storage stability, adhesion, and transferability before thermal curing. Alternatively, the epoxy curing agent (c) may be a microcapsule-type curing agent.

[0072] As the epoxy curing agent (c), an amide-based compound is preferred, and dicyandiamide is more preferred, from the viewpoint of increasing the adhesive strength of the adhesive sheet after thermal curing. Furthermore, the epoxy curing agent (c) preferably contains a urea-based compound and / or an imidazole-based compound. Furthermore, it is particularly preferred to contain a urea-based compound and / or an imidazole-based compound in addition to the amide-based compound. The urea-based compound and the imidazole-based compound (particularly the urea-based compound) act as a curing accelerator when the epoxy resin reacts with the amide-based compound, and have the function of accelerating the reaction rate.

[0073] The content of the epoxy curing agent (c) in the adhesive sheet is preferably 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass, even more preferably 4 to 16 parts by mass, and particularly preferably 4.5 to 15 parts by mass, per 100 parts by mass of the total epoxy resin (particularly, per 100 parts by mass of the epoxy resin (a) and the rubber-modified epoxy resin (b) combined). When the content is within the above range, the adhesive strength of the adhesive sheet after thermal curing is higher.

[0074] The content of the amide compound in the adhesive sheet is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass, per 100 parts by mass of the total epoxy resin (particularly, 100 parts by mass of the epoxy resin (a) and the rubber-modified epoxy resin (b) combined). When the content is within the above range, the adhesive strength of the adhesive sheet after thermal curing is higher.

[0075] The content of the urea compound and / or imidazole compound in the adhesive sheet is preferably 1 to 10 parts by mass, more preferably 1.5 to 8 parts by mass, and even more preferably 2 to 7 parts by mass, per 100 parts by mass of the total epoxy resin (particularly, per 100 parts by mass of the epoxy resin (a) and the rubber-modified epoxy resin (b) combined). When the content is within the above range, the adhesive strength of the adhesive sheet after thermal curing is higher.

[0076] (Polyfunctional Compound (d)) The adhesive sheet preferably contains a polyfunctional compound (d) having two or more reactive double bonds in the molecule. One type of polyfunctional compound (d) may be used alone, or two or more types may be used.

[0077] The polyfunctional compound (d) is preferably a compound that is cured by active energy rays. That is, the reactive double bond preferably has an active energy ray-polymerizable group. By including such a polyfunctional compound (d), the adhesive sheet has active energy ray-curability.

[0078] Examples of the active energy ray-polymerizable group include a vinyl group, a propenyl group, an isopropenyl group, a (meth)acryloyl group (an acryloyl group and / or a methacryloyl group), and a (meth)acrylamide group (an acrylamide group and / or a methacrylamide group). Among these, a (meth)acryloyl group and a (meth)acrylamide group are preferred from the viewpoint of a fast reaction rate. In this specification, "(meth)acryloyl" means "acryloyl" or "methacryloyl", or both. The same applies to "(meth)acrylic".

[0079] Examples of the polyfunctional compound (d) having a (meth)acryloyl group include polyfunctional (meth)acrylates such as 1,6-hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. The average number of moles of ethylene glycol or propylene glycol added in polyethylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate is not particularly limited, but is preferably 2 to 10, and more preferably 2 to 6.

[0080] Examples of the polyfunctional compound (d) having a (meth)acrylamide group include polyfunctional (meth)acrylamides such as methylenebis(meth)acrylamide, ethylenebis(meth)acrylamide, diallyl(meth)acrylamide, N-[tris(3-(meth)acrylamidopropoxymethyl)methyl](meth)acrylamide, N,N-bis(2-(meth)acrylamideethyl)(meth)acrylamide, 4,7,10-trioxa-1,13-tridecanebis(meth)acrylamide, and N,N'-1,2-ethanedylbis[N-(2-(meth)acrylamideethyl)](meth)acrylamide.

[0081] The number of reactive double bonds possessed by the polyfunctional compound (d) is 2 or more, preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 to 3.

[0082] The polyfunctional compound (d) is preferably a low molecular weight compound, and although there are no particular limitations on the molecular weight, it is preferably 50 to 500. When the molecular weight is within the above range, the adhesive sheet has an appropriate elastic modulus G' after irradiation with active energy rays, and the transferability is superior.

[0083] The content of the polyfunctional compound (d) in the adhesive sheet is preferably 0.1 to 12 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of the total amount of epoxy resin (particularly, per 100 parts by mass of the total of the epoxy resin (a) and the rubber-modified epoxy resin (b)). When the content is within the above range, the adhesive sheet has an appropriate elastic modulus G' after irradiation with active energy rays, and the transferability is superior.

[0084] (Photopolymerization initiator (e)) The adhesive sheet may contain a photopolymerization initiator (e). When the photopolymerization initiator (e) is contained, curing of the adhesive sheet by irradiation with active energy rays is promoted. The photopolymerization initiator (e) is preferably contained together with the polyfunctional compound (d). Only one type of photopolymerization initiator (e) may be used, or two or more types may be used.

[0085] The photopolymerization initiator (e) is not particularly limited, and examples thereof include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators. Other examples include acylphosphine oxide-based photopolymerization initiators and titanocene-based photopolymerization initiators. Examples of the benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, and anisole methyl ether. Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone. Examples of the α-ketol-based photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(O-ethoxycarbonyl)-oxime. Examples of the benzoin-based photopolymerization initiator include benzoin. Examples of the benzyl-based photopolymerization initiator include benzyl. Examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenyl ketone, etc. Examples of the ketal-based photopolymerization initiator include benzyl dimethyl ketal, etc.Examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone. Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Examples of the titanocene-based photopolymerization initiator include bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium.

[0086] The content of the photopolymerization initiator (e) in the adhesive sheet is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the total amount of epoxy resin (particularly, per 100 parts by mass of the total of the epoxy resin (a) and the rubber-modified epoxy resin (b)). When the content is within the above range, curing of the adhesive sheet upon irradiation with active energy rays is suitably promoted.

[0087] (Filler) The adhesive sheet preferably contains a filler. The inclusion of a filler makes it easier to adjust the elastic modulus G'(A2) and elastic modulus G'(B2) of the adhesive sheet to fall within the above-mentioned ranges. 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.

[0088] Examples of constituent materials for the inorganic filler 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, silica (crystalline silica, amorphous silica, etc.), etc. Furthermore, examples of constituent materials for the inorganic filler include simple metals such as aluminum, gold, silver, copper, nickel, etc., alloys, amorphous carbon black, graphite, etc.

[0089] Examples of the inorganic filler include the fillers of the above-mentioned constituent materials, as well as mica, talc, kaolin, wollastonite, feldspar, syenite, chlorite, bentonite, montmorillonite, dolomite, quartz, cristobalite, hollow ceramic beads, hollow glass beads, and glass beads.

[0090] Examples of materials constituting the organic filler include polymethyl methacrylate (PMMA), polyimide, polyamideimide, polyetheretherketone, polyetherimide, and polyesterimide.

[0091] The shape of the filler is not particularly limited, and may be various shapes such as spherical, flake (scale-like), dendritic, fibrous, and amorphous (polyhedral).

[0092] Of the above fillers, inorganic fillers are preferred, and silica fillers are more preferred.

[0093] The silica filler may be subjected to a surface treatment such as hydrophobic treatment. Examples of the treating agent used for the hydrophobic treatment include organic silyl compounds such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane, methyltrialkoxysilane, dimethyldialkoxysilane, trimethylalkoxysilane, ethyltrichlorosilane, propyltrichlorosilane, hexyltrichlorosilane, long-chain alkyltrichlorosilane, ethyltrialkoxysilane, propyltrialkoxysilane, hexyltrialkoxysilane, long-chain alkyltrialkoxysilane, methacrylsilane, fluoroalkylsilane, and perfluoroalkylsilane; and silicone compounds such as dimethylpolysiloxane (silicone oil), methylphenylpolysiloxane, methylhydrogenpolysiloxane, and amino-modified silicone.

[0094] The average particle diameter of the filler is preferably 50 nm or less, more preferably 40 nm or less. When the average particle diameter is 50 nm or less, the adhesive is less likely to extrude. The average particle diameter of the filler is preferably 7 nm or more, more preferably 10 nm or more. When the average particle diameter is 7 nm or more, the bulk density is high and handling is excellent. The average particle diameter of the inorganic filler can be determined, for example, using a photometric particle size distribution meter (for example, product name "LA-910", manufactured by Horiba, Ltd.).

[0095] The specific surface area of ​​the filler is 30 m ２ / g or more is preferable, and 100m ２ / g or more. ２ From the viewpoint of being able to select particles with high bulk density and excellent handleability, the specific surface area of ​​the filler is set to 500 m ２ / g or less, and more preferably 350m ２ / g or less.

[0096] The specific surface area of ​​the filler per 100 g of the adhesive sheet is 600 to 6000 m ２ is preferable, and more preferably 800 to 5000 m ２ The specific surface area is 600 m ２ When the specific surface area is 6000 m or more, the adhesive is less likely to protrude. ２ When the thickness is equal to or less than this, the adhesive layer has excellent conformability to the irregularities of the adherend and excellent shear adhesive strength.

[0097] The content of the filler in the adhesive sheet is preferably 0.5 to 20 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 2 to 8 parts by mass, per 100 parts by mass of the total epoxy resin (particularly, 100 parts by mass of the epoxy resin (a) and the rubber-modified epoxy resin (b) combined). When the content is 0.5 parts by mass or more, the elastic modulus G'(A2) and elastic modulus G'(B2) of the adhesive sheet can be increased, and extrusion of the adhesive can be further suppressed. When the content is 20 parts by mass or less, the transferability of the adhesive sheet is superior.

[0098] The adhesive sheet may contain a colorant. The colorant may be a pigment or a dye. Examples of colorants include black colorants, cyan colorants, magenta colorants, and yellow colorants. The adhesive sheet may contain only one type of colorant, or two or more types of colorants. The content of the colorant in the adhesive sheet is preferably 0.05 to 5% by mass, and more preferably 0.1 to 2% by mass, relative to the total amount (100% by mass) of the adhesive sheet.

[0099] The adhesive sheet may contain other components in addition to the various components described above, provided that the effects of the present invention are not impaired. Examples of such other components include other curing accelerators, thermoplastic resins, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), antioxidants, antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, UV absorbers, polymerization inhibitors, flame retardants, silane coupling agents, ion trapping agents, and foil-like materials. Only one of the above other components may be used, or two or more may be used.

[0100] The thickness of the adhesive sheet is not particularly limited, but is preferably 10 to 1000 μm, more preferably 30 to 750 μm, and even more preferably 50 to 500 μm. When the thickness is 10 μm or more, the adhesive sheet exhibits superior adhesiveness when used to bond members together.

[0101] The adhesive sheet is made by using two sheets of AL alloy A5052 polished with 100-grain sandpaper, bonding one adhesive surface to the polished surface of one sheet of AL alloy A5052, irradiating it with active energy rays, bonding the polished surface of the other sheet of AL alloy A5052 to the other adhesive surface, and then sandwiching the two sheets of AL alloy A5052 together to bond the two adhesive surfaces together and heat-curing. The shear adhesive strength measured at a tensile speed of 1.3 mm / min and a peel angle of 0° is preferably 5 MPa or more, more preferably 7 MPa or more, more preferably 10 MPa or more, and even more preferably 15 MPa. A shear adhesive strength of 1 MPa or more ensures excellent adhesion between components. The active energy ray irradiation need only be performed on at least a portion of the adhesive sheet, and it is preferable that the shear adhesive strength after irradiating the entire surface of the adhesive sheet with active energy rays be within the above range. Generally, the shear adhesive strength after irradiating a portion of the adhesive sheet with active energy rays is higher than the shear adhesive strength after irradiating the entire surface of the adhesive sheet with active energy rays.

[0102] The adhesive sheet of the present invention is preferably used for bonding members together. Because the adhesive sheet has excellent adhesion to metals, it is preferably used for bonding metal members together. It is also preferably used for bonding metal members together. The adhesive sheet of the present invention also has excellent adhesion between members made of different materials. Therefore, the adhesive sheet of the present invention is also preferably used for bonding metal members to fiber-reinforced resin members. Examples of the reinforcing fibers include known or commonly used reinforcing fibers, such as carbon fiber, glass fiber, aramid fiber, boron fiber, graphite fiber, silicon carbide fiber, high-strength polyethylene fiber, tungsten carbide fiber, and polyparaphenylenebenzoxazole fiber (PBO fiber).

[0103] The adhesive sheet may have a release liner (separator) attached to the surface (adhesive surface) of the adhesive sheet until use. Each adhesive surface on both sides of the adhesive sheet may be protected by two release liners, or may be protected by a single release liner with release surfaces on both sides in a rolled form (rolled body). The release liner is used as a protective material for the adhesive sheet and is peeled off when the sheet is attached to the adherend. The release liner is not necessarily provided.

[0104] The release liner can be a conventional release paper, and is not particularly limited. Examples include substrates with a release treatment layer, low-adhesion substrates made of fluoropolymers, and low-adhesion substrates made of non-polar polymers. Examples of substrates with a release treatment layer include plastic films and papers surface-treated with release agents such as silicone-based, long-chain alkyl-based, fluorine-based, and molybdenum sulfide-based release agents. Examples of fluorine-based polymers in the low-adhesion substrates made of fluoropolymers include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymers, and chlorofluoroethylene-vinylidene fluoride copolymers. Examples of non-polar polymers include olefin-based resins (e.g., polyethylene, polypropylene, etc.). The release liner can be formed by known or conventional methods. The thickness of the release liner is also not particularly limited.

[0105] The adhesive sheet can be produced, for example, by applying an adhesive composition for forming the adhesive sheet to a release liner and, if necessary, drying and solidifying the resulting adhesive composition layer. The adhesive composition can be produced by mixing the various components described above, such as the epoxy resin (a), rubber-modified epoxy resin (b), epoxy curing agent (C), polyfunctional compound (d), polymerization initiator (e), and the filler. Alternatively, the adhesive sheet can be produced by dissolving or dispersing the various components in a solvent such as an organic solvent and then mixing them.

[0106] The adhesive sheet is used, for example, as follows: First, the release liner is peeled from one adhesive surface of the adhesive sheet, and the exposed adhesive surface is adhered to one adherend for close contact. Next, at least a portion of the adhesive sheet is cured by irradiation with active energy rays, and then the release liner is peeled from the other adhesive surface. Next, the other adherend is adhered to the other exposed adhesive surface, and the adhesive sheet is then heated to thermally cure. In this way, the adhesive sheet can be used to adhere adherends to each other.

[0107] For this reason, when the adhesive sheet of the present invention is laminated to a member with one adhesive surface, irradiated with active energy rays, and then the release liner laminated to the other adhesive surface is peeled off, the adhesive sheet has excellent transferability, and the release liner can be easily peeled off from the adhesive surface of the adhesive sheet without peeling off the adhesive sheet and the release liner from the member to which it is laminated. Furthermore, after being laminated to an adherend, the adhesive sheet of the present invention is heated to cure the adhesive sheet and firmly adhere to the member. When the adherend members are laminated together via the adhesive sheet, or when the adhesive sheet is heated to cure, the adhesive in the adhesive sheet is less likely to squeeze out from between the members due to pressure or heat.

[0108] [Laminate Manufacturing Method] According to the laminate manufacturing method of the present invention, a laminate can be manufactured in which a first adherend and a second adherend are bonded together via an adhesive sheet. The manufacturing method includes at least the steps of irradiating the adhesive sheet (curable adhesive sheet) bonded to the first adherend with active energy rays to cure it (active energy ray irradiation step), bonding the second adherend to the adhesive sheet (second bonding step), and heating the adhesive sheet to thermally cure it (thermal curing step). Note that in the manufacturing method of the present invention, each step may be performed by the same company or different companies.

[0109] The manufacturing method may include a step of bonding one adhesive surface of the curable adhesive sheet, which is a double-sided adhesive sheet, to the first adherend (first bonding step) before the active energy ray irradiation step. Furthermore, the manufacturing method may include a step of irradiating a portion of the adhesive sheet in a surface direction with active energy rays to cure it, and then bonding the adhesive sheet to the first adherend (active energy ray irradiation / first bonding step) instead of the active energy ray irradiation step.

[0110] The curable adhesive sheet has active energy ray curability and heat curability. The adhesive sheet of the present invention can be used as the curable adhesive sheet.

[0111] Figures 2 and 3 show a process for producing a laminate according to one embodiment of the present invention. The production method of the present invention will be described below with reference to the flow charts shown in Figures 2 and 3. Figures 2 and 3 show an example in which the adhesive sheet shown in Figure 1 is used as the curable adhesive sheet.

[0112] FIG. 2 is a diagram illustrating a process including the active energy ray irradiation step. First, as shown in FIG. 2( a), one release liner 2 is peeled from the adhesive sheet 1. Then, as shown in FIG. 2( b), the exposed adhesive surface 1a is attached to a first adherend 4 (first attachment step). Next, a release liner 3 is attached to the adhesive surface 1b, and in a state where oxygen is blocked, active energy rays L are irradiated to a portion of the surface of the adhesive sheet 1 to form a cured portion 11 (active energy ray irradiation step). By irradiating a portion of the surface of the non-cured portion 12 that has not been irradiated with active energy rays L, the adhesive sheet has both a cured portion 11 that has been cured by the active energy ray irradiation and a non-cured portion 12 that has not been irradiated with active energy rays and is not cured. Therefore, after thermal curing, the adhesive sheet has high adhesive strength to the adherend, and the adhesive sheet is less likely to peel from the adherend in the resulting laminate.

[0113] FIG. 3 is a diagram illustrating a process that includes the active energy ray irradiation / first attachment step instead of the active energy ray irradiation step. First, as shown in FIG. 3( a), while the adhesive sheet 1 is sandwiched between two release liners 2 and 3 and is shielded from oxygen, active energy rays L are irradiated to a portion of the surface of the adhesive sheet 1 to form a cured portion 11. By irradiating a portion of the surface with active energy rays, the adhesive sheet has a cured portion 11 that has been cured by the active energy ray irradiation and an uncured portion 12 that has not been irradiated with active energy rays and is not cured. Therefore, after thermal curing, the adhesive sheet has high adhesive strength to the adherend, and the resulting laminate is less likely to peel from the adherend. Then, as shown in FIG. 3( b), one release liner 2 is peeled from the adhesive sheet 1. Then, as shown in FIG. 3( c), the exposed adhesive surface 1a is attached to a first adherend 4 (active energy ray irradiation / first attachment step).

[0114] 2(c) and 3(a), the adhesive sheet 1 in the state where it is irradiated with active energy rays L has the following region (A) and region (B): Region (A): Elastic modulus G'(A1) at 20°C is 1×10 ３ ~5 x 10 ６ Pa, elastic modulus G' (A2) at 80°C is 1 x 10 ４ Region (B): The elastic modulus G'(B1) at 20°C is greater than the elastic modulus G'(A1), and the elastic modulus G'(B2) at 80°C is less than 1×10 ３ Area above Pa

[0115] Before irradiation with active energy rays L, the entire surface of adhesive sheet 1 corresponds to region (A) above, which corresponds to non-cured portion 12, and cured portion 11 formed by irradiation with active energy rays L corresponds to region (B). Therefore, adhesive sheet 1 shown in Figures 2(c) and 3(a) is adhesive sheet X described above.

[0116] It is preferable that the part in the surface direction is one end in the surface direction (particularly the outer peripheral edge). That is, it is preferable that the cured portion 11 (region (B)) is located at one end in the surface direction of the adhesive sheet 1 (particularly the outer peripheral edge). By irradiating one end in the surface direction (particularly the outer peripheral edge), the adhesive is less likely to protrude from the end that is the cured portion during thermal curing, and the other region is an uncured portion, resulting in excellent adhesion to the adherend. The width of the outer peripheral edge from the outer periphery is not particularly limited, and is, for example, 0.5 to 10 mm. Figure 2(c) shows an example in which the cured portion 11 is formed by irradiating only the outer peripheral edge with active energy rays. The uncured portion 12 is an area that is not irradiated with active energy rays.

[0117] 2(c) and 3(a), the curable adhesive sheet is irradiated with active energy rays over at least a portion of its surface, but it may be irradiated over the entire surface. Although the cured portion 11 has poorer adhesion to the adherend than the uncured portion 12, the above-mentioned elastic modulus G'(B1) ensures sufficient transferability when peeling off the release liner 3.

[0118] Examples of the active energy rays include ionizing radiation such as α rays, β rays, γ rays, neutron rays, and electron beams, as well as ultraviolet rays and ultraviolet lasers.

[0119] 2(d) and 3(d), the release liner 3 is peeled off to expose the adhesive surface 1b. At this time, by peeling the release liner 3 from the cured portion 11, the release liner 3 can be peeled off relatively easily also from the uncured portion 12, and the uncured portion 12 is sufficiently adhered to the first adherend 4, resulting in excellent transferability.

[0120] Next, as shown in FIGS. 2( e) and 3( e), a second adherend 5 is attached to the exposed adhesive surface 1b of the adhesive sheet 1 (second attachment step). At this time, the uncured portion 12 exhibits excellent adhesion to the second adherend 5. Then, as shown in FIGS. 2( f) and 3( f), the adhesive sheet 1 is heated and thermally cured to form an adhesive sheet 1′ (thermal curing step). In the thermal curing step, the cured portion 11 is cured by active energy ray irradiation, so adhesive is less likely to extrude from the cured portion 11 side. However, adhesive may extrude from the uncured portion 12 side of the adhesive sheet 1. However, if the adhesive sheet 1 is annular in shape, with the cured portion 11 on the outer periphery and the uncured portion 12 on the inner periphery, adhesive extrusion from the uncured portion 12 side is not noticeable and is therefore not a problem.

[0121] The first adherend and the second adherend are not particularly limited, and any appropriate material to be adhered can be selected. Because the adhesive sheet has excellent adhesion to metals, it is preferable that at least one of the first adherend and the second adherend be a metal member. Furthermore, because the adhesive sheet also has excellent adhesion between members made of different materials, it is preferable that the combination of the first adherend and the second adherend be a combination of a metal member and a metal member, or a combination of a metal member and a fiber-reinforced resin member.

[0122] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples in any way. The compositions of the components constituting the adhesive sheets in the examples and comparative examples are shown in the tables. However, in the tables, the units of the numerical values ​​representing the composition of the adhesive sheet are relative "parts by mass" within the adhesive sheet.

[0123] Example 1 (Preparation of Adhesive Sheet) 3.5 parts by mass of silica filler (product name "Aerosil RY-200", manufactured by Nippon Aerosil Co., Ltd.) was added to 50 parts by mass of bisphenol A epoxy resin (product name "jER-834", manufactured by Mitsubishi Chemical Corporation) that had been heated at 60°C for 1 hour, and the mixture was stirred at 2000 rpm for 3 minutes using a planetary mixer (product name "Awatori Rentaro", manufactured by Thinky Corporation) to obtain a silica filler dispersion. 53.5 parts by mass of the silica filler dispersion, 50 parts by mass of a rubber-modified epoxy resin (trade name "HyPoxRK84L", manufactured by HUNTSMAN), 3.5 parts by mass of polyethylene glycol diacrylate (n=4) (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.5 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name "Omnirad 184", manufactured by IGM Resins), and 0.5 parts by mass of 2,2-dimethoxy-2-phenylacetophenone (trade name "Omnirad 651", manufactured by IGM Resins) were added to a small kneader (trade name "Xplore", manufactured by DSM), and the mixture was kneaded at 80°C for 15 minutes. Furthermore, 3.8 parts by mass of a dicyandiamide curing agent (trade name "Omicure DDA-50", manufactured by HUNTSMAN) and 5 parts by mass of 1,1'-(4-methyl-1,3-phenylene)bis(3,3'-dimethylurea) (trade name "Omicure U-24M", manufactured by HUNTSMAN) were added, and the mixture was kneaded at 80°C for 5 minutes to obtain a kneaded product.

[0124] Next, the above kneaded material was sandwiched between the release-treated surfaces of two 75 μm thick PET release liners, each having a release-treated surface, and pressure treatment was performed at 60° C. for 1 minute so that the thickness became 0.1 mm, thereby producing an adhesive sheet.

[0125] (Measurement of Elastic Modulus G' Before UV Irradiation) The release liners on both sides of the prepared adhesive sheet were peeled off, laminated to a thickness of 1 mm or more, and cut to a diameter of 8 mm to prepare a test specimen. Using a rheometer (trade name "ARES G2", manufactured by TA Instruments), dynamic viscoelasticity was measured under conditions of a frequency of 1 Hz, a heating rate of 5°C / min, and a measurement temperature of 0 to 100°C. If the elastic modulus during measurement fell to 1 kPa or less, the measurement was discontinued even at temperatures below 100°C. Furthermore, if the temperature at which the elastic modulus fell to 1 kPa or less was 80°C or less, the elastic modulus at 80°C was recorded as 1 kPa or less. In this manner, the elastic modulus G' at 20°C and 80°C before UV irradiation was measured.

[0126] (Measurement of Elastic Modulus G' after UV Irradiation) The prepared adhesive sheet was sandwiched between two release liners and irradiated with a UV irradiator (product name "FL15BL", manufactured by Toshiba Corporation) at 1500 mJ / m ２ For the adhesive sheet thus obtained after ultraviolet irradiation, the elastic modulus G' at 20°C and 80°C after ultraviolet irradiation was measured in the same manner as for the elastic modulus G' before ultraviolet irradiation.

[0127] (Evaluation of Transferability) The prepared adhesive sheet was cut into a piece 10 mm wide x 50 mm long. SUS304BA, which had been washed with ethyl acetate, was used as the adherend. One release liner of the cut adhesive sheet was peeled off, and the adhesive surface was attached to the adherend. The adhesive sheet was then irradiated with 1500 mJ / m using an ultraviolet irradiator (product name "FL15BL", manufactured by Toshiba Corporation). ２ After leaving the sample to stand for 5 minutes at room temperature, when the other release liner was peeled off, if the adhesive remained on the adherend, it was evaluated as "Good", and if the adhesive remained on the other release liner or on both the adherend and the other release liner, it was evaluated as "Poor".

[0128] (Evaluation of adhesive extrusion) The prepared adhesive sheet was sandwiched between two release liners and irradiated with an ultraviolet ray at 1500 mJ / m using an ultraviolet ray irradiation device (product name "FL15BL", manufactured by Toshiba Corporation). ２The adhesive sheet was then cut to a diameter of 8.0 mm, one release liner was peeled off, and the exposed adhesive surface was attached to a glass slide (product name "S1225", manufactured by Matsunami Glass Industry Co., Ltd.). The other release liner was then peeled off, and the other exposed adhesive surface was attached to another glass slide. The two glass slides were heated in an oven at 100°C for 1 hour while being pressed with a force of 6 kPa. After cooling, the adhesive sheet was observed through the glass slide, and evaluation was performed with an adhesive sheet diameter of 8.5 mm or less indicated as "good" and an adhesive sheet diameter of more than 8.5 mm indicated as "poor."

[0129] (Measurement of Elastic Modulus E') The prepared adhesive sheet was sandwiched between two release liners and irradiated with an ultraviolet ray at 1500 mJ / m using an ultraviolet ray irradiator (product name "FL15BL", manufactured by Toshiba Corporation). ２ After irradiating with ultraviolet light under the above conditions, the adhesive sheet was cured by heating in an oven at 100°C for 1 hour. The cured adhesive sheet was cut into a piece 5 mm wide x 50 mm long, and the release liners on both sides were removed. Next, using a rheometer (trade name "RSA G2", manufactured by TA Instruments), the dynamic viscoelasticity was measured at a frequency of 1 Hz, a heating rate of 5°C / min, and a measurement temperature range of -50 to 150°C. In this manner, the elastic modulus E' at 80°C after thermal curing was measured.

[0130] Examples 2 to 7, Comparative Examples 1 and 2 Adhesive sheets were produced in the same manner as in Example 1, except that the types and amounts of the various raw materials used in producing the adhesive compositions were changed as shown in Table 1. Then, for the obtained adhesive sheets, the elastic modulus G' before and after ultraviolet irradiation was measured, transferability was evaluated, adhesive extrusion was evaluated, and the elastic modulus E' after thermal curing was measured in the same manner as in Example 1.

[0131] The results of each evaluation are shown in Table 1.

[0132]

[0133] Examples 8-9 and Comparative Examples 3-4 (Preparation of Adhesive Sheets) Adhesive sheets were prepared in the same manner as in Example 1, except that the types and amounts of the various raw materials used to prepare the adhesive compositions were changed as shown in Table 2.

[0134] (Measurement of Elastic Modulus G' Before Electron Beam Irradiation) The elastic modulus G' of the adhesive sheet was measured at 20°C and 80°C before ultraviolet irradiation in the same manner as in Example 1.

[0135] (Measurement of Elastic Modulus G' After Electron Beam Irradiation) The elastic modulus G' after electron beam irradiation at 20°C and 80°C was measured in the same manner as in Example 1, except that the adhesive sheet was irradiated with electron beams at 100 kGy using an electron beam device (product name "EC300", manufactured by ESI) instead of ultraviolet irradiation.

[0136] (Evaluation of Transferability) The transferability was evaluated in the same manner as in Example 1, except that instead of ultraviolet irradiation, electron beam irradiation was performed at 100 kGy using an electron beam device (product name "EC300", manufactured by ESI).

[0137] (Evaluation of glue extrusion) The adhesive sheet was evaluated for glue extrusion in the same manner as in Example 1, except that instead of ultraviolet irradiation, electron beam irradiation was performed at 100 kGy using an electron beam device (product name "EC300", manufactured by ESI).

[0138] (Measurement of Elastic Modulus E') The elastic modulus E' at 80°C after thermal curing was measured in the same manner as in Example 1, except that the adhesive sheet was irradiated with electron beams at 100 kGy using an electron beam device (product name "EC300", manufactured by ESI) instead of ultraviolet irradiation.

[0139] The results of each evaluation are shown in Table 2.

[0140]

[0141] Example 10 and Comparative Examples 5 and 6 (Preparation of Adhesive Sheets) Adhesive sheets were prepared in the same manner as in Example 1, except that the types and amounts of the various raw materials used to prepare the adhesive compositions were changed as shown in Table 3.

[0142] (Measurement of Elastic Modulus G' Before UV Laser Irradiation) The elastic modulus G' of the adhesive sheet was measured at 20°C and 80°C before UV laser irradiation in the same manner as in Example 1.

[0143] (Measurement of Elastic Modulus G' after UV Laser Irradiation) Instead of ultraviolet irradiation, the adhesive sheet was irradiated with a 355 nm UV pulse laser at 40 kHz and 6900 mJ / cm ２ The elastic modulus G' at 20°C and 80°C after UV laser irradiation was measured in the same manner as in Example 1, except that UV laser irradiation was performed at 1000 kJ / cm.

[0144] (Evaluation of transferability) Instead of ultraviolet irradiation, a 355 nm UV pulse laser irradiation device was used under the condition of 40 kHz and 6900 mJ / cm ２ The transferability was evaluated in the same manner as in Example 1, except that UV laser irradiation was performed.

[0145] (Evaluation of adhesive extrusion) The adhesive sheet was subjected to an evaluation of adhesive extrusion using a 355 nm UV pulse laser irradiation device at 40 kHz with 6900 mJ / cm instead of ultraviolet irradiation. ２ The adhesive extrusion was evaluated in the same manner as in Example 1, except that UV laser irradiation was performed.

[0146] (Measurement of Elastic Modulus E') The above adhesive sheet was subjected to irradiation with 6900 mJ / cm under the condition of 40 kHz using a 355 nm UV pulse laser irradiation device instead of ultraviolet irradiation. ２ The elastic modulus E' at 80° C. after heat curing was measured in the same manner as in Example 1, except that UV laser irradiation was performed.

[0147] The results of each evaluation are shown in Table 3.

[0148]

[0149] As shown in Tables 1 to 3, the adhesive sheets of the present invention exhibited excellent transferability after irradiation with active energy rays, and did not produce adhesive extrusion during heat curing. On the other hand, when the elastic modulus G' at 20°C after irradiation with active energy rays was equal to or lower than the elastic modulus G' at 20°C before irradiation with active energy rays, the transferability after irradiation with active energy rays was poor (Comparative Examples 2, 4, and 6). Furthermore, when the elastic modulus G' at 80°C after irradiation with active energy rays was 1×10 ３ When the viscosity was less than Pa, the adhesive overflowed during thermal curing (Comparative Examples 1, 3, and 5).

[0150] Examples 11-13 (Transferability Evaluation) The adhesive sheets of Examples 1-3 were cut into test pieces measuring 10 mm wide x 50 mm long. SUS304BA stainless steel sheets washed with ethyl acetate were used as the adherend. One release liner was peeled off from the cut-out adhesive sheet, and the adhesive surface was attached to the adherend. UV irradiation was then carried out in the same manner as in Examples 1-3, except that UV irradiation was carried out only on a 1 mm-wide circular area from the periphery of the test piece. After leaving the test piece at room temperature for 5 minutes, the other release liner was peeled off. If the adhesive remained on the adherend, it was evaluated as "Good." If the adhesive remained on the other release liner or on both the adherend and the other release liner, it was evaluated as "Poor." Note that, as in Examples 1-3, test pieces in which UV irradiation was carried out on the entire surface were designated "full irradiation," while those in which UV irradiation was carried out on only the circular area around the periphery of the test piece were designated "partial irradiation." The results of the transferability evaluation for "full irradiation" are those for Examples 1-3.

[0151] (Evaluation of adhesive extrusion) The prepared adhesive sheet was sandwiched between two release liners and irradiated with an ultraviolet ray at 1500 mJ / m using an ultraviolet ray irradiation device (product name "FL15BL", manufactured by Toshiba Corporation). ２ Under the conditions, ultraviolet irradiation was performed only on a 1 mm-wide circular portion from the outer periphery of the adhesive sheet. Next, an adhesive sheet with a diameter of 8.0 mm was cut out, one release liner was peeled off, and one exposed adhesive surface was attached to a glass slide (product name "S1225", manufactured by Matsunami Glass Industry Co., Ltd.). The other release liner was then peeled off, and the other exposed adhesive surface was attached to another glass slide. The two glass slides were heated in an oven at 100°C for 1 hour while being pressed with a force of 6 kPa. After cooling, the adhesive sheet was observed through the glass slide. No adhesive extrusion was observed from the outer periphery where ultraviolet irradiation had been performed, and the result was rated as "Good." The evaluation results for adhesive extrusion in the "full irradiation" test were those for Examples 1 to 3.

[0152] (Shear adhesive strength) The basic operation was carried out in accordance with JIS K6850:1999. Specifically, first, an AL alloy A5052 measuring 25 mm wide x 100 mm long x 1.6 mm thick was polished three times each in the 45° and 135° directions along the length with sandpaper of 100 grit. The polished surface was washed with ethyl acetate and air-dried for 30 minutes to obtain an adherend. On the other hand, the adhesive sheets produced in Examples 1 to 3 were cut into a width of 25 mm x length of 12.5 mm. One release liner of the cut adhesive sheet was peeled off, and the adhesive surface was attached to the adherend. Then, using an ultraviolet irradiation device (product name "FL15BL", manufactured by Toshiba Corporation), 1500 mJ / m ２ Under these conditions, the entire adhesive sheet or only a 1 mm-wide circular portion from the outer periphery of the test specimen was irradiated with ultraviolet light to obtain a "full-irradiation" sample and a "partial-irradiation" sample. The other release liner was then peeled off and attached to another adherend. If the adhesive sheet did not transfer when the other release liner was peeled off, it was transferred by laminating at 60°C for 10 seconds. The two adherends were temporarily fixed at approximately 2 to 7 kPa. In the temporarily fixed state, the adhesive sheet was cured by heating in an oven at 150°C for 1 hour, and after cooling, the temporary fixation was released to obtain a test specimen. 25 mm ends of the obtained test specimen were clamped in the chucks of a tensile tester, and the tester was moved at a rate of 1.3 mm / min until fracture occurred. The maximum stress was taken as the shear adhesive strength.

[0153] The results of each evaluation are shown in Table 4.

[0154]

[0155] As shown in Table 4, by partially irradiating the adhesive sheet, a laminate was obtained that had excellent transferability, no glue overflow, and a sufficiently high shear adhesive strength compared to when the entire sheet was irradiated, resulting in a laminate with even higher adhesive strength.

[0156] The various raw materials shown in Tables 1 to 4 are as follows: (Bisphenol-type epoxy resin) jER-834: trade name "jER-834", semi-solid bisphenol A-type epoxy resin, epoxy equivalent weight 230 to 270 g / eq, manufactured by Mitsubishi Chemical Corporation (Rubber-modified epoxy resin) HyPoxRK84L: trade name "HyPoxRK84L", epoxy resin obtained by reacting bisphenol A-type epoxy with CTBN, epoxy equivalent weight 1250 to 1500 g / eq, manufactured by HUNTSMAN (Epoxy curing agent) Omicure DDA-50: trade name "Omicure DDA-50", dicyandiamide, manufactured by HUNTSMAN Omicure U-24M: trade name "Omicure U-24M", U-24M", 1,1'-(4-methyl-1,3-phenylene)bis(3,3'-dimethylurea), manufactured by HUNTSMAN (polyfunctional compounds) PGDA: polyethylene glycol diacrylate (average number of moles added: 4) 1,6-HDDA: 1,6-hexanediol diacrylate TMPTA: trimethylolpropane triacrylate (photopolymerization initiators) Omnirad 651: trade name "Omnirad 651", manufactured by IGM Resins B.V. Omnirad 184: trade name "Omnirad 184", manufactured by IGM Resins B.V. Aerosil RY-200 (Filler) manufactured by Aerosil Corporation: Product name "Aerosil RY-200", hydrophobized fumed silica, specific surface area 175 to 225 m ２ / g, average particle size 12 nm, manufactured by Nippon Aerosil Co., Ltd.

[0157] Variations of the present invention are disclosed below. [Appendix 1] The elastic modulus G'(A1) at 20°C before irradiation with active energy rays is 1 x 10 ３ ~5 x 10 ６ Pa, the elastic modulus G' (A2) at 80°C is 1 x 10 ４ After irradiation with active energy rays, the elastic modulus G'(B1) at 20°C is greater than the elastic modulus G'(A1), and the elastic modulus G'(B2) at 80°C is 1×10 ３ The elastic modulus E' at 20°C after heat curing is 1 x 10 ８ ~1 x 10 １１[Appendix 2] The elastic modulus G'(B1) at 20°C is 1 x 10 ３ Pa super 5×10 ８ [Appendix 3] An adhesive sheet according to Appendix 1, wherein the modulus of elasticity G'(A1) at 20°C is 1 x 10 Pa or less. [Appendix 4] An adhesive sheet having the following region (A) and the following region (B) in the planar direction: Region (A): The modulus of elasticity G'(A1) at 20°C is 1 x 10 ３ ~5 x 10 ６ Pa, elastic modulus G' (A2) at 80°C is 1 x 10 ４ Region (B): The elastic modulus G'(B1) at 20°C is greater than the elastic modulus G'(A1), and the elastic modulus G'(B2) at 80°C is less than 1×10 ３ [Appendix 4] An adhesive sheet according to claim 1 or 2, comprising the following region (A) which is not irradiated with active energy rays, and the following region (B) which is formed by irradiating a part of the surface direction of the region (A) with active energy rays: Region (A): Elastic modulus G'(A1) at 20°C is 1 x 10 ３ ~5 x 10 ６ Pa, elastic modulus G' (A2) at 80°C is 1 x 10 ４ Region (B): The elastic modulus G'(B1) at 20°C is greater than the elastic modulus G'(A1), and the elastic modulus G'(B2) at 80°C is less than 1×10 ３[Appendix 5] The adhesive sheet according to Appendices 3 or 4, having the region (B) at one end in the planar direction. [Appendix 6] The adhesive sheet according to any one of Appendices 1 to 5, containing an epoxy resin as a thermosetting component. [Appendix 7] The adhesive sheet according to Appendices 6, wherein the epoxy resin contains an epoxy resin (a) having an epoxy equivalent of 200 to 800 g / eq and a rubber-modified epoxy resin (b). [Appendix 8] The adhesive sheet according to Appendices 6 or 7, containing 0.5 to 30 parts by mass of an epoxy curing agent (c) per 100 parts by mass of the epoxy resin. [Appendix 9] The adhesive sheet according to Appendices 8, wherein the epoxy curing agent (c) contains dicyandiamide. [Appendix 10] The adhesive sheet according to any one of Appendices 1 to 9, containing a polyfunctional compound (d) having two or more reactive double bonds in the molecule. [Appendix 11] The adhesive sheet according to Appendices 10, wherein the polyfunctional compound (d) has a (meth)acryloyl group and / or a (meth)acrylamide group. [Appendix 12] The adhesive sheet according to Appendices 10 or 11, containing 0.1 to 12 parts by mass of the polyfunctional compound (d) per 100 parts by mass of the epoxy resin. [Appendix 13] The adhesive sheet according to any one of Appendices 10 to 12, containing 0.1 to 5 parts by mass of a photopolymerization initiator (e) per 100 parts by mass of the epoxy resin. [Appendix 14] The adhesive sheet according to any one of Appendices 1 to 13, which is used to bond members, at least one of which is made of metal. [Appendix 15] The adhesive sheet according to Appendices 14, which is used to bond metal members to each other, or a metal member to a fiber-reinforced resin member. [Appendix 16] A method for producing a laminate in which a first adherend and a second adherend are bonded together via the adhesive sheet, the method comprising the steps of: irradiating an adhesive sheet, which is bonded to a first adherend, with active energy rays to a portion of its surface in the direction of the surface thereof and curing it; or irradiating an adhesive sheet, which is bonded to a first adherend, with active energy rays to cure it; and then bonding the adhesive sheet to the first adherend; bonding a second adherend to the adhesive sheet; and heating the adhesive sheet to thermally cure it. [Appendix 17] The production method according to Appendix 16, in which at least one of the first adherend and the second adherend is a metal member.[Appendix 18] The manufacturing method according to appendix 17, wherein the combination of the first adherend and the second adherend is a combination of a metal member and a metal member, or a combination of a metal member and a fiber-reinforced resin member. [Appendix 19] The manufacturing method according to any one of appendices 16 to 18, wherein the part in the planar direction is one end in the planar direction.

[0158] 1, 1' adhesive sheet 2, 3 release liner 4 first adherend 5 second adherend 11 cured portion 12 non-cured portion

Claims

1. The elastic modulus G' (A1) at 20°C before irradiation with active energy rays is 1 x 10 ３ ~5×10 ６ Pa, the elastic modulus G' (A2) at 80°C is 1 x 10 ４ After irradiation with active energy rays, the elastic modulus G'(B1) at 20°C is greater than the elastic modulus G'(A1), and the elastic modulus G'(B2) at 80°C is less than 1×10 ３ The elastic modulus E' at 20°C after heat curing is 1 x 10 ８ ~1×10 １１ Pa, an adhesive sheet.

2. The elastic modulus G' (B1) at 20°C is 1 x 10 ３ Pa super 5×10 ８ The adhesive sheet according to claim 1 , wherein the viscosity is 0.05 Pa or less.

3. An adhesive sheet having the following region (A) and the following region (B) in the planar direction: Region (A): Elastic modulus G' (A1) at 20°C is 1×10 ３ ~5×10 ６ Pa, the elastic modulus G' (A2) at 80°C is 1 x 10 ４ Region (B): The elastic modulus G' (B1) at 20°C is greater than the elastic modulus G' (A1), and the elastic modulus G' (B2) at 80°C is less than 1×10 ３ Area above Pa 4. An adhesive sheet according to claim 3, having said region (B) at one end in said surface direction.

5. The adhesive sheet according to any one of claims 1 to 4, which contains an epoxy resin as a thermosetting component.

6. The adhesive sheet according to claim 5, wherein the epoxy resin comprises an epoxy resin (a) having an epoxy equivalent of 200 to 800 g / eq and a rubber-modified epoxy resin (b).

7. The adhesive sheet according to claim 6, which contains 0.5 to 30 parts by mass of an epoxy curing agent (c) per 100 parts by mass of the epoxy resin.

8. The adhesive sheet according to claim 7, wherein the epoxy curing agent (c) contains dicyandiamide.

9. The adhesive sheet according to any one of claims 1 to 4, which contains a polyfunctional compound (d) having two or more reactive double bonds in the molecule.

10. The adhesive sheet according to claim 9, wherein the polyfunctional compound (d) has a (meth)acryloyl group and / or a (meth)acrylamide group.

11. The adhesive sheet according to claim 9, which contains 0.1 to 12 parts by mass of the polyfunctional compound (d) per 100 parts by mass of the epoxy resin.

12. The adhesive sheet according to claim 9, which contains 0.1 to 5 parts by mass of a photopolymerization initiator (e) per 100 parts by mass of the epoxy resin.

13. The adhesive sheet according to any one of claims 1 to 4, which is used for bonding members, at least one of which is made of a metal.

14. The adhesive sheet according to claim 13, which is used for bonding metal members together or between a metal member and a fiber-reinforced resin member.

15. A method for producing a laminate in which a first adherend and a second adherend are bonded together via an adhesive sheet, the method comprising the steps of: irradiating a part of the surface direction of an adhesive sheet, which is bonded to a first adherend, with active energy rays to cure the adhesive sheet; or irradiating a part of the surface direction of the adhesive sheet with active energy rays to cure the adhesive sheet, and then bonding the adhesive sheet to the first adherend; bonding a second adherend to the adhesive sheet; and heating the adhesive sheet to thermally cure the adhesive sheet.

16. The manufacturing method according to claim 15, wherein at least one of the first adherend and the second adherend is a metal member.

17. The manufacturing method according to claim 16, wherein the combination of the first adherend and the second adherend is a combination of a metal member and a metal member, or a combination of a metal member and a fiber-reinforced resin member.

18. The manufacturing method according to any one of claims 15 to 17, wherein the part in the plane direction is one end in the plane direction.

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