Primer composition

Abstract

A primer composition comprising: (A) an acrylate, a methacrylate, or a (co)polymer of the two; (B) an organosilicon compound represented by the following formula (1), an organosilicon compound represented by the following formula (2), or both (R 1 and R 2 is an alkyl group, R 3 is a divalent hydrocarbon group, R 4 is an alkylene group or a carbonyl group, R 5 is a monovalent hydrocarbon group, a is 0 or 1, and b is an integer from 0 to 3); (C) one or more condensation catalysts selected from tetraalkoxytitanium, tetraalkoxyzirconium, tetraalkoxytin, trialkoxyaluminum and partial hydrolyzates thereof; and (D) a solvent.

Description

Technical Field

[0001] The present invention relates to a primer composition, and more particularly to a primer composition for imparting adhesion between an adherend such as a polyimide resin and a silicone cured product. Background Art

[0002] Silicone rubber has excellent heat resistance, cold resistance, light resistance, electrical insulation, etc., and has been used to bond sealing materials, electrical insulation materials, packaging materials, etc. At this time, if the adhesion of silicone rubber to the substrate is insufficient, the substrate is generally primed in advance.

[0003] As primer compositions for cured products of addition-curable silicone compositions used for bonding sealing materials, electrical insulating materials, packaging materials, etc., compositions composed of silane coupling agents and / or their reaction products, polyester resins, acrylic resins, compositions composed of phenyl-containing siloxanes, alkyl silicates, chlorosilanes, etc. are known.

[0004] In recent years, polyimide resin has been used in various applications as a high-function material with excellent mechanical strength, heat resistance, electrical insulation, etc. Its uses are varied, and as an example, flexible printed circuits, etc. can be cited. In the case of converting the substrate into a polyimide resin with excellent heat resistance, a material with excellent heat resistance is also required for the peripheral materials. Therefore, it is expected that the use of the organosilicon material of the polyimide component will increase. However, in general, organosilicon cured products are difficult to bond with polyimide resins, and a method for improving the bonding property with polyimide resins is required.

[0005] Furthermore, the following prior art documents can be cited as prior art documents related to the present invention.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-19909 Summary of the invention

[0009] Problems to be solved by the invention

[0010] The present invention has been made in view of the above-mentioned actual situation, and an object of the present invention is to provide a primer composition capable of firmly bonding an adherend such as a polyimide resin to a silicone cured product.

[0011] Means for solving problems

[0012] The present inventors have conducted intensive studies to achieve the above object and have found that a composition comprising a (meth)acrylate (co)polymer and an organosilicon compound having a specific functional group introduced therein can firmly bond an adherend such as a polyimide resin to a silicone cured product, thereby completing the present invention.

[0013] That is, the present invention provides:

[0014] 1. A primer composition comprising:

[0015] (A) acrylates, methacrylates or (co)polymers thereof;

[0016] (B) an organosilicon compound represented by the following formula (1), an organosilicon compound represented by the following formula (2), or both;

[0017] [Chemistry 1]

[0018]

[0019] In the formula, R 1 and R 2 are independently an alkyl group having 1 to 4 carbon atoms, R 3 are independently a divalent hydrocarbon group having 1 to 30 carbon atoms, R 4 are independently an alkylene group having 1 to 6 carbon atoms or a carbonyl group, R 5 are independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, a is independently 0 or 1, and b is an integer of 0 to 3,

[0020] (C) at least one condensation catalyst selected from the group consisting of tetraalkoxytitanium, tetraalkoxyzirconium, tetraalkoxytin, trialkoxyaluminum, and partial hydrolyzates thereof; and

[0021] (D) solvent;

[0022] 2. The primer composition according to 1, wherein the acrylate, methacrylate, or both of the acrylates and methacrylates constituting the component (A) contain a compound having one or more SiH groups in one molecule;

[0023] 3. The primer composition according to 1 or 2, wherein the component (B) comprises an organosilicon compound represented by the above formula (1), and R 4 is a carbonyl group;

[0024] 4. The primer composition according to any one of 1 to 3, further comprising (E) an organosilicon compound represented by the following formula (3),

[0025] (R 6 O) c R 7 d Si(3)

[0026] In the formula, R 6 are independently an alkyl group having 1 to 4 carbon atoms, R 7 Each of the above is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted by a halogen atom, an acryloyl group, a methacryloyl group or an epoxy group, wherein c is an integer of 1 to 4, d is an integer of 0 to 3, and c+d=4;

[0027] 5. A method for bonding an adherend to a silicone cured product, comprising: supplying the primer composition according to any one of 1 to 4 to the adherend; and disposing a curable silicone composition on the adherend supplied with the primer composition, and curing the silicone composition;

[0028] 6. The bonding method according to 5, wherein the adherend is a polyimide resin.

[0029] Effects of the Invention

[0030] The primer composition of the present invention can firmly bond an adherend such as a polyimide resin to a cured silicone product, and can be used as an adhesive for semiconductor devices requiring high reliability. DETAILED DESCRIPTION

[0031] The present invention is described in detail below.

[0032] The primer composition of the present invention contains (A) a (meth)acrylate (co)polymer, (B) an organosilicon compound, (C) a condensation catalyst and (D) a solvent.

[0033] (1)(A)Component

[0034] (A) Component is an acrylate, a methacrylate, or a (co)polymer of the two.

[0035] The primer composition containing such a component (A) forms a flexible film on an adherend, and forms a bond by an addition reaction with the addition-curable silicone composition.

[0036] As the (meth)acrylate constituting the component (A), an alkyl (meth)acrylate having an alkyl group with 1 to 12 carbon atoms, particularly 1 to 4 carbon atoms, is preferred.

[0037] Examples of the acrylic acid ester include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, isoamyl acrylate, n-hexyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isononyl acrylate, n-decyl acrylate, and isodecyl acrylate.

[0038] Examples of the methacrylate include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isononyl methacrylate, n-decyl methacrylate, and isodecyl methacrylate.

[0039] As the (meth)acrylate constituting the component (A), it is preferred to use a (meth)acrylate having one or more SiH groups in one molecule.

[0040] Examples of the (meth)acrylate having one or more SiH groups in one molecule include compounds represented by the following formulae (4) to (6).

[0041] [Chemistry 2]

[0042]

[0043] R 8 are independently a hydrogen atom or a methyl group.

[0044] R 9 are independently monovalent organic groups. 9 The monovalent organic group is preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 3 carbon atoms. Examples of the monovalent hydrocarbon group include straight-chain or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, and octyl; cycloalkyl groups such as cyclohexyl; alkenyl groups such as vinyl, allyl (2-propenyl), and 1-propenyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and groups in which a part or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine, bromine, and chlorine, cyano, and the like, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl. As R 9 , preferably methyl, ethyl, phenyl, particularly preferably methyl.

[0045] R 10 are independently divalent organic groups. 10 The divalent organic group is preferably an unsubstituted or substituted divalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 3 carbon atoms. Examples of the divalent hydrocarbon group include straight-chain or branched alkylene groups such as methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene; cycloalkylene groups such as cyclohexylene; and arylene groups such as phenylene and naphthylene. In addition, these groups may be groups in which a part or all of the hydrogen atoms are substituted with halogen atoms such as fluorine, bromine, and chlorine, cyano, and the like, such as tetrafluoroethylene and hexafluoropropylene. As R10 , preferably methylene, ethylene, trimethylene, and particularly preferably trimethylene.

[0046] n is 0, 1 or 2. m is 0 or a positive integer, and p is a positive integer. q and r are positive integers. In formulas (5) and (6), the arrangement of the siloxane units in parentheses may be arbitrary.

[0047] These (meth)acrylates may be used alone or in combination of two or more. The component (A) preferably contains a compound represented by formula (4), and it is particularly preferred to use other acrylates and / or methacrylates in combination with the compound represented by formula (4).

[0048] In this case, there is no particular limitation on the ratio of other acrylates and / or methacrylates to the compound represented by formula (4). In terms of molar ratio, the ratio of other acrylates and / or methacrylates to the compound represented by formula (4) is preferably 1:1 to 20:1, more preferably 1:1 to 15:1, and even more preferably 1:1 to 10:1.

[0049] Examples of the compound represented by formula (4) include the following compounds.

[0050] [Chemistry 3]

[0051]

[0052] Examples of the compound represented by formula (5) include the following compounds.

[0053] [Chemistry 4]

[0054]

[0055] (In the formula, m and p are the same as above. The arrangement of the siloxane units in parentheses may be arbitrary.)

[0056] Examples of the compound represented by formula (6) include the following compounds.

[0057] [Chemistry 5]

[0058]

[0059] (In the formula, q and r are the same as above. The arrangement of each siloxane unit can be arbitrary.)

[0060] (A) Component can be obtained by polymerizing (meth)acrylate using a radical polymerization initiator such as 2,2'-azobisisobutyronitrile (AIBN) as described later.

[0061] The weight average molecular weight of the component (A) is not particularly limited, but is preferably 100 to 500,000, and more preferably 10,000 to 200,000. In the present invention, the weight average molecular weight is a standard polystyrene conversion value obtained by gel permeation chromatography (GPC).

[0062] The amount of component (A) is not particularly limited as long as it is an amount that dissolves component (D) described later, but is preferably 0.1 to 20% by mass of the entire composition, more preferably 0.1 to 10% by mass, and further preferably 0.5 to 5% by mass. If it is within such a range, the generation of concavities and convexities on the surface of the obtained film can be prevented, and sufficient performance as a primer composition can be obtained.

[0063] (2) (B) Component

[0064] The component (B) is an organosilicon compound represented by the following formula (1), an organosilicon compound represented by the following formula (2), or both.

[0065] [Chemistry 6]

[0066]

[0067] R 1 and R 2 Each of R is independently an alkyl group having 1 to 4 carbon atoms. 1 and R 2 Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, and methyl and ethyl groups are preferred.

[0068] R 3 Each of R is independently a divalent hydrocarbon group having 1 to 30 carbon atoms. 3 The divalent hydrocarbon group represented by ' may include straight-chain or branched alkylene groups such as methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene; cycloalkylene groups such as cyclohexylene; arylene groups such as phenylene and naphthylene, etc., preferably a divalent hydrocarbon group having 3 to 8 carbon atoms, more preferably trimethylene.

[0069] R 4 Each of R is independently an alkylene group having 1 to 6 carbon atoms or a carbonyl group. 4 The alkylene group having 1 to 6 carbon atoms may be a straight chain or branched chain alkylene group such as methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, a cycloalkylene group such as cyclohexylene, an arylene group such as phenylene, etc. 4 , preferably a carbonyl group.

[0070] R 5 Each of R is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms. 5The monovalent hydrocarbon group having 1 to 20 carbon atoms may include a straight-chain or branched alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, octyl, etc.; a cycloalkyl group such as cyclohexyl; an alkenyl group such as vinyl, allyl, propenyl, etc.; an aryl group such as phenyl, tolyl, xylyl, naphthyl, etc.; an aralkyl group such as benzyl, phenylethyl, phenylpropyl, etc.; and groups in which a part or all of the hydrogen atoms of these groups are substituted with a halogen atom such as fluorine, bromine, chlorine, or a cyano group, such as a chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group, a cyanoethyl group, etc. As R 5 , preferably an alkyl group having 1 to 10 carbon atoms, particularly preferably an alkyl group having 1 to 8 carbon atoms, further preferably a methyl group, an ethyl group, an n-propyl group, or a butyl group.

[0071] a is independently 0 or 1, and is preferably 0. b is an integer of 0 to 3, and is preferably 0.

[0072] The component (B) may be used alone or in combination of two or more. The component (B) preferably comprises a compound represented by formula (1), wherein R 4 More preferred is a carbonyl group.

[0073] Examples of the compound represented by formula (1) include the following compounds.

[0074] [Chemistry 7]

[0075]

[0076] Examples of the compound represented by formula (2) include the following compounds.

[0077] [Chemistry 8]

[0078]

[0079] The amount of component (B) is preferably 0.1 to 20% by mass of the entire composition, more preferably 0.1 to 10% by mass, and still more preferably 0.5 to 5% by mass. Within such a range, the generation of surface irregularities of the obtained film can be prevented, and sufficient performance as a primer composition can be obtained.

[0080] (3) (C) Component

[0081] The condensation catalyst of the component (C) is one or more condensation catalysts selected from tetraalkoxytitanium, tetraalkoxyzirconium, tetraalkoxytin, trialkoxyaluminum and partial hydrolyzates thereof, and promotes the condensation reaction of the alkoxysilyl group of the component (B).

[0082] The alkoxy group of the component (C) is preferably an alkoxy group having an alkyl group with 1 to 6 carbon atoms, particularly preferably an alkoxy group having 1 to 4 carbon atoms, and examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, and tert-butoxy.

[0083] Examples of the tetraalkoxytitanium include tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium, and tetra-n-butoxytitanium, and tetra-n-butoxytitanium is particularly preferred.

[0084] Examples of the tetraalkoxyzirconium include tetramethoxyzirconium, tetraethoxyzirconium, tetra-n-propoxyzirconium, tetraisopropoxyzirconium, and tetra-n-butoxyzirconium, and tetra-n-butoxyzirconium is particularly preferred.

[0085] Examples of the tetraalkoxytin include tetramethoxytin, tetraethoxytin, tetra-n-propoxytin, tetra-isopropoxytin, tetra-n-butoxytin, and tetra-tert-butoxytin. Among them, tetra-tert-butoxytin is particularly preferred.

[0086] Examples of the trialkoxyaluminum include aluminum (III) ethoxide, aluminum (III) isopropoxide, aluminum (III) sec-butoxide, aluminum (III) n-butoxide, and mono-sec-butoxydiisopropoxide aluminum. Among them, aluminum (III) n-butoxide and mono-sec-butoxydiisopropoxide aluminum are preferred.

[0087] These may be used alone or in combination of two or more.

[0088] The amount of the component (C) is preferably 1 to 300 parts by mass, more preferably 20 to 250 parts by mass, based on 100 parts by mass of the component (B). Within such a range, a film having excellent strength can be obtained.

[0089] (4) (D) Component

[0090] The solvent of the component (D) is not particularly limited as long as it can dissolve the components (A), (B), and (C) and the optional components described below, and a known organic solvent can be used.

[0091] Examples of the solvent include aromatic hydrocarbon solvents such as xylene, toluene, and benzene; aliphatic hydrocarbon solvents such as heptane, hexane, and volatile oil; halogenated hydrocarbon solvents such as trichloroethylene, perchloroethylene, and dichloromethane; ester solvents such as ethyl acetate and 1-propylene glycol methyl ether acetate; ether solvents such as tetrahydrofuran and diethyl ether; ketone solvents such as methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone; alcohol solvents such as ethanol, isopropanol, and butanol; rubber volatile oil, silicone solvents, etc. Among these, ethyl acetate, 1-propylene glycol methyl ether acetate, tetrahydrofuran, and acetone are preferably used.

[0092] The component (D) may be used alone or in combination of two or more thereof as a mixed solvent, depending on the evaporation rate during the coating operation of the primer composition.

[0093] By matching (D) component, the workability during the coating and drying of the primer composition can be adjusted. The amount of (D) component is not particularly limited, preferably more than 60% by mass of the entire primer composition, more preferably 80-95% by mass, and further preferably 85-90% by mass. If it is such a range, when forming a coating film of the primer composition, it can be made uniform, and the concavo-convex of the coating film surface can be suppressed. In addition, the amount of the above-mentioned (D) component, when (A) component etc. are added as a solution, represents the total amount in the composition including the solvent in the solution.

[0094] (5) (E) Component

[0095] The primer composition of the present invention may further contain an organosilicon compound represented by the following formula (3) as the component (E).

[0096] (R 6 O) c R 7 d Si(3)

[0097] R 6 Each of R is independently an alkyl group having 1 to 4 carbon atoms. 6 Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, and methyl and ethyl groups are preferred.

[0098] R 7 Each of R is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a halogen atom, an acryloyl group, a methacryloyl group or an epoxy group. 7 The monovalent hydrocarbon group having 1 to 10 carbon atoms may be exemplified by 9 The monovalent hydrocarbon group is the same as exemplified above, and preferably a methyl group or a phenyl group.

[0099] c is an integer of 1 to 4, preferably 3 or 4, d is an integer of 0 to 3, preferably 0 or 1, and c+d=4.

[0100] Examples of the component (E) include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane. Among these, tetramethoxysilane and tetraethoxysilane are particularly preferred.

[0101] The amount of the component (E) when used is not particularly limited, but is preferably 1 to 20% by mass, more preferably 2 to 10% by mass, based on the entire composition.

[0102] [Other ingredients]

[0103] The primer composition of the present invention may further contain other optional components such as a phosphor, a reinforcing filler, a dye, a pigment, a heat resistance improver, an antioxidant, and an adhesion promoter, within a range not impairing the purpose of the present invention.

[0104] [Method for producing primer composition]

[0105] The primer composition of the present invention can be obtained, for example, by uniformly mixing the above-mentioned components (A), (B), (C) and (D), and optionally the component (E) and other optional components using a mixer.

[0106] [Bonding method]

[0107] The primer composition of the present invention can be used to improve the adhesion between an adherend and a silicone cured product. As a method for bonding an adherend and a silicone cured product using the primer composition of the present invention, for example, the following method can be adopted: supplying the primer composition of the present invention to an adherend, disposing a curable silicone composition on the adherend supplied with the primer composition, and curing the silicone composition.

[0108] The primer composition of the present invention can be applied to the adherend by a known method such as brushing or spraying. After the primer composition is applied to the adherend, it can be air-dried for 5 minutes to 24 hours, preferably 10 minutes to 12 hours, and then coated with a curable silicone composition, and the silicone composition can be cured at room temperature (25°C) or under heating to bond the adherend to the silicone cured product. It can also be heated after air-drying to fully cure the film, and then coated with a curable silicone composition, and the adherend and the silicone cured product can be bonded in the same manner as described above.

[0109] As the adherend used in the present invention, organic resins such as acrylic resin, phenolic resin, epoxy resin, polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyamide resin, polyimide resin, and polypropylene resin, various metals, glass, etc. can be listed. Among these, polyimide resins are particularly preferred. As polyimide resins, for example, HJA-A4-100 (produced by Hokushin Co., Ltd.), Kapton 100H, and Kapton 100EN (all produced by Toray Industries, Ltd.) can be listed.

[0110] Examples of curable silicone compositions include addition-curable, peroxide-curable, and condensation-curable silicone rubber compositions. In the present invention, addition-curable silicone rubber compositions are preferred. As addition-curable silicone rubber compositions, known compositions can be used. Generally, compositions containing addition reaction catalysts such as organopolysiloxanes having two or more vinyl groups or the like in one molecule, organohydrogenpolysiloxanes having two or more SiH groups in one molecule, and platinum group metal catalysts can be used. Examples of addition-curable silicone rubber compositions include KE-106 and KER-2600 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0111] Example

[0112] The present invention will be specifically described below using synthesis examples, examples, and comparative examples, but the present invention is not limited to these examples.

[0113] [Synthesis example 1]

[0114] 40 parts by mass of methyl methacrylate, 14 parts by mass of a methacrylate containing a SiH group represented by the following structural formula (7), 230 parts by mass of ethyl acetate, and 0.25 parts by mass of AIBN were heated and stirred at 90°C for 6 hours to obtain an ethyl acetate solution containing 8% by mass (value at 105°C x 3 hours) of the nonvolatile matter of the copolymer.

[0115] The weight average molecular weight of the obtained copolymer was 95,000 as a standard polystyrene conversion value measured using GPC (HLC-8320GPC, manufactured by Tosoh Corporation) with tetrahydrofuran as an eluting solvent.

[0116] [Chemistry 9]

[0117]

[0118] [Examples 1-1 to 1-7, Comparative Examples 1-1, 1-2]

[0119] Primer compositions (I) to (VII) and comparative primer compositions (VIII) and (IX) were prepared by mixing the following components in the amounts shown in Table 1. The numerical values ​​in Table 1 represent parts by mass.

[0120] (A): 8 mass % ethyl acetate solution of the copolymer obtained in Synthesis Example 1

[0121] (B1): 3-ureidopropyltrimethoxysilane (KBM-585, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0122] [Chemistry 10]

[0123]

[0124] (B2): 3-aminopropyltriethoxysilane (KBE-903, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0125] [Chemistry 11]

[0126]

[0127] (B3): 3-triethoxysilyl-N-(1,3-dimethyl-butenyl)propylamine (KBE-9103P, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0128] [Chemistry 12]

[0129]

[0130] (C): Tetra-n-butoxytitanium

[0131] (D): Ethyl acetate

[0132] (E):Tetraethoxysilane

[0133] [Table 1]

[0134]

[0135] [Examples 2-1 to 2-7, Comparative Examples 2-1, 2-2]

[0136] The primer compositions (I) to (VII) and comparative primer compositions (VIII) and (IX) obtained in Examples 1-1 to 1-7 and Comparative Examples 1-1 and 1-2 were evaluated for adhesion by the following adhesion test.

[0137] [Comparative Example 2-3]

[0138] The addition-curable silicone primer composition (X) (PRIMER NO4 (carbon-functional silane primer), manufactured by Shin-Etsu Chemical Co., Ltd.) was used as it was, and the adhesion was evaluated by the following adhesion test.

[0139] [Comparative Examples 2-4]

[0140] The adhesion was evaluated by the following adhesion test except that no primer composition was used. The results are shown in Table 2.

[0141] [Adhesion test]

[0142] As adherends, three types of polyimide sheets cut into 30 mm × 30 mm (HJA-A4-100, manufactured by Hokushin Co., Ltd.; Kapton 100H, manufactured by Toray Industries, Ltd.; Kapton 100EN, manufactured by Toray Industries, Ltd.) were used, and the primer composition was brush-coated on the adherends and air-dried at 25°C for 15 minutes. An addition-curable silicone composition (KE-106, manufactured by Shin-Etsu Chemical Co., Ltd.) was dripped thereon and cured to prepare a laminated sheet.

[0143] A cut was made near the center of the organic silicone cured material on the obtained laminated sheet with a cutter to confirm the state of the organic silicone cured material when the laminated sheet was folded. The case where the organic silicone cured material peeled off when the laminated sheet was folded was evaluated as ×, the case where the organic silicone cured material did not peel off even when the laminated sheet was folded, but the organic silicone cured material peeled off the entire surface when it was peeled off by hand was evaluated as △, and the case where the organic silicone cured material did not peel off even when the laminated sheet was folded, but cohesion failure occurred when the organic silicone cured material was peeled off by hand was evaluated as 0.

[0144] [Table 2]

[0145]

[0146] As shown in Table 2, Examples 2-1 to 2-7 show significantly improved adhesion of the addition-curable silicone cured product to the polyimide sheet compared to Comparative Examples 2-1 to 2-3 using primer compositions different from the primer composition of the present invention and Comparative Example 2-4 using no primer composition.

Claims

1. A method for bonding a polyimide resin to a cured silicone product, comprising: a step of applying a primer composition containing the following components (A) to (D) to the polyimide resin; and a step of placing a curable silicone composition on the polyimide resin to which the primer composition has been applied, and curing the silicone composition. (A) a polymer of acrylate or methacrylate or a copolymer of acrylate and methacrylate, wherein the acrylate or methacrylate comprises a compound selected from the group consisting of compounds represented by the following formulae (4) to (6); [Chemistry 1] In the formula, R 8 are independently a hydrogen atom or a methyl group, R 9 are independently monovalent organic groups, R 10 are independently divalent organic groups, n is 0, 1 or 2, m is 0 or a positive integer, p is a positive integer, q and r are positive integers, and in formulas (5) and (6), the arrangement of the siloxane units in parentheses is arbitrary; (B) an organosilicon compound represented by the following formula (1), an organosilicon compound represented by the following formula (2), or both; [Chemistry 2] In the formula, R 1 and R 2 are independently an alkyl group having 1 to 4 carbon atoms, R 3 are independently a divalent hydrocarbon group having 1 to 30 carbon atoms, R 4 are independently an alkylene group having 1 to 6 carbon atoms or a carbonyl group, R 5 are independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, a is independently 0 or 1, and b is an integer of 0 to 3, (C) at least one condensation catalyst selected from the group consisting of tetraalkoxytitanium, tetraalkoxyzirconium, tetraalkoxytin, trialkoxyaluminum, and partial hydrolyzates thereof; and (D) Solvent.

2. The bonding method according to claim 1, wherein: The component (B) comprises an organosilicon compound represented by the above formula (1), and R 4 It is a carbonyl group.

3. The bonding method according to claim 1, wherein: The primer composition further comprises (E) an organosilicon compound represented by the following formula (3), (R) 6 (About) c R 7 d You (3) In the formula, R 6 are independently an alkyl group having 1 to 4 carbon atoms, R 7 They are independently a monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a halogen atom, an acryloyl group, a methacryloyl group or an epoxy group; c is an integer of 1 to 4; d is an integer of 0 to 3; and c+d=4.

4. The bonding method according to claim 2, wherein: The primer composition further comprises (E) an organosilicon compound represented by the following formula (3), (R) 6 (About) c R 7 d You (3) In the formula, R 6 are independently an alkyl group having 1 to 4 carbon atoms, R 7 They are independently a monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a halogen atom, an acryloyl group, a methacryloyl group or an epoxy group; c is an integer of 1 to 4; d is an integer of 0 to 3; and c+d=4.

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