Curable resin composition, adhesive sheet, prepreg, cured product, substrate with cured product, and electronic device

Abstract

To provide a thermosetting resin composition that yields a cured product with superior laminating property to an LCP base material, superior resistance to plating liquids (alkali resistance and acid resistance), and superior insulation reliability after a heat cycle test; an adhesive sheet; a prepreg; a cured product; a substrate with a cured product; and an electronic device including the substrate with a cured product.SOLUTION: Provided is a curable resin composition including a terminal-modified polyimide resin (A) and a curable compound (B), the terminal-modified polyimide resin (A) having a structure originating from a tetracarboxylic acid half ester (a1), obtained as a reaction product of a tetracarboxylic dianhydride and an alcohol compound, and a diamine (a2), and further having a monoamine-modified structure at a molecular chain terminal, wherein 40 mol% or more of the diamine (a2) is a dimer diamine.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition containing a polyimide resin, and also to an adhesive sheet, a prepreg, a cured product, a substrate with the cured product, and an electronic device having the substrate with the cured product, each made of the curable resin composition. [Background technology]

[0002] Polyimide resins have excellent heat resistance and chemical resistance, and are therefore widely used in a wide range of fields, including electrical insulation and electronics. For example, Patent Document 1 discloses a method for obtaining a polyimide film by inkjet coating a thermosetting ink composition containing an amide acid having a specific structure and curing the resulting coating. Patent Document 2 discloses a polyimide adhesive containing a terminally modified polyimide, a crosslinking agent, and an organic solvent. This terminally modified polyimide uses a reaction product of a primary monoamine and an acid anhydride-terminated polyimide, which is a reaction product of a monomer group including an aromatic tetracarboxylic acid anhydride and a dimer diamine.

[0003] Patent Document 3 discloses a polyimide-based adhesive composition containing a polyimide resin obtained by reacting aromatic tetracarboxylic acids with diamines containing a specific amount of dimer diamine, a thermosetting resin, a flame retardant, and an organic solvent. Patent Document 4 also discloses a polyimide-based adhesive composition using a polyimide resin obtained by further chain-extending the polyimide resin with diamines containing a specific amount of dimer diamine. Patent Document 4 discloses a resin film exhibiting specific dielectric properties, containing a polyimide obtained by reacting a tetracarboxylic anhydride component with a diamine component having a dimer structure. Patent Document 5 discloses a resin composition containing a polyimide resin containing aliphatic, alicyclic, and / or aromatic tetracarboxylic acid residues and diamine residues containing dimer diamine, an epoxy resin, and a curing agent capable of curing epoxy groups. Patent Document 6 discloses a polyamic acid resin that is a reaction product of an aminophenol compound, an aliphatic diamino compound, a tetrabasic acid dianhydride, and an aromatic diamino compound, and is an imidized product of the polyamic acid resin having amino groups at both ends. Also disclosed is a resin composition containing a terminal-modified polyimide resin obtained using this polyimide resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-032501 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-191049 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-199645 [Patent Document 4] Japanese Patent Publication No. 2020-056011 [Patent Document 5] Japanese Patent Application Laid-Open No. 2015-117278 [Patent Document 6] International Publication No. 2020 / 189354 Summary of the Invention [Problem to be solved by the invention]

[0005] In the electronics field, with the spread of electronic devices such as smartphones and tablet devices, reliability over a wide temperature range is required, and in particular, high insulation reliability is required against extreme temperature changes (hereinafter referred to as insulation reliability after heat cycle testing).

[0006] Furthermore, when exposed to alkaline or acidic solutions during the plating process in the manufacture of electronic components, there is a problem in that lifting or peeling easily occurs between the components. To solve these problems, molecular weight stability of the materials used at high temperatures over long periods is important. The amic acid-containing thermosetting ink composition disclosed in Patent Document 1 uses polyamic acid, a polyimide precursor, resulting in poor molecular weight stability over time. Furthermore, the ink composition uses polyamic acid with a high acid value, which makes it susceptible to thermal decomposition at high temperatures. Furthermore, the polyimide adhesives disclosed in Patent Documents 2 to 5, which have a dimer skeleton and enhanced thermal stability through terminal modification, contain oligomers in some of the dimer diamines used as raw materials. The amide and urethane bonds derived from the oligomers tend to be cleaved at high temperatures or when exposed to alkaline aqueous solutions or acid solutions. This results in insufficient polymer stability, resulting in reduced insulation reliability after heat cycle testing and reduced plating solution resistance.

[0007] Furthermore, with the recent advances in high-speed and high-capacity wireless communications, liquid crystal polymer (LCP) substrates with low dielectric properties have been attracting attention, and there is a market demand for materials that are compatible with LCP substrates. However, LCP substrates have a problem in that they are prone to temporary adhesion defects during the lamination process in which they are temporarily attached to a thermosetting sheet. For example, the polyimide resin composition disclosed in Patent Document 6 has a problem in that it lacks laminability with LCP substrates.

[0008] The present invention has been made in view of the above-mentioned background, and aims to provide a curable resin composition that can give a cured product that has excellent molecular weight stability at high temperatures, excellent lamination properties to an LCP substrate after a moist heat test, excellent plating solution resistance (alkali resistance and acid resistance), and excellent insulation reliability after a heat cycle test; an adhesive sheet, a prepreg, a cured product, a substrate with the cured product, and an electronic device having a substrate with the cured product. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the problems of the present invention can be solved by the following aspects, and have thus completed the present invention. [1]: A curable resin composition containing a terminally modified polyimide resin (A) and a curable compound (B), wherein the terminally modified polyimide resin (A) has a structure derived from a tetracarboxylic acid half ester (a1), which is a reaction product of a tetracarboxylic acid dianhydride and an alcohol compound, and a diamine (a2), and has a monoamine-modified structure at the molecular chain end, and 40 mol % or more of the diamine (a2) is a dimer diamine. [2]: The curable resin composition according to [1], characterized in that the curable compound (B) contains at least one selected from the group consisting of epoxy compounds, cyanate ester compounds, maleimide compounds, vinyl group-containing compounds (excluding allyl group-containing compounds and (meth)acryloyl group-containing compounds), allyl group-containing compounds, and (meth)acryloyl group-containing compounds. [3]: The curable resin composition according to [1] or [2], characterized in that the terminal-modified polyimide resin (A) accounts for 5 to 99 mass% of 100 mass% in total of the terminal-modified polyimide resin (A) and the curable compound (B). [4]: The curable resin composition according to any one of [1] to [3], further comprising a filler. [5]: The curable resin composition according to any one of [1] to [4], wherein the terminal-modified polyimide resin (A) has a weight-average molecular weight of 10,000 to 100,000. [6]: A laminate sheet comprising a substrate and a resin composition layer formed on the substrate using the curable resin composition according to any one of [1] to [5]. [7]: A prepreg obtained by impregnating a substrate with the curable resin composition according to any one of [1] to [5]. [8]: A cured product obtained from the curable resin composition according to any one of [1] to [5]. [9]: A substrate having the cured product according to [8].

[10] : An electronic device comprising a substrate with the cured product according to [9]. [Effects of the Invention]

[0010] The present invention has the excellent effect of providing a thermosetting resin composition that can give a cured product that has excellent molecular weight stability at high temperatures, excellent lamination properties to LCP substrates and plating solution resistance (alkali resistance and acid resistance), and excellent insulation reliability after a heat cycle test; an adhesive sheet; a prepreg; a cured product; a substrate with the cured product; and an electronic device having a substrate with the cured product. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic top view for explaining an evaluation board according to the present embodiment. [Figure 2] FIG. 2 is a schematic top view for explaining an evaluation board according to the present embodiment. [Figure 3] FIG. 2 is a schematic top view for explaining an evaluation board according to the present embodiment. [Figure 4] 4 is a cross-sectional view taken along line IV-IV of FIG. 3. [Figure 5] 1A to 1C are schematic explanatory views of a laser processing evaluation method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below. Needless to say, other embodiments are also included within the scope of the present invention as long as they are consistent with the spirit of the present invention. Furthermore, in this specification, a numerical range specified using "to" includes the numerical values ​​before and after "to" as the range of the lower and upper limits. Furthermore, in this specification, "film" and "sheet" are synonymous and are not distinguished by thickness. Furthermore, unless otherwise noted, the various components appearing in this specification may be used independently, either singly or in combination of two or more types. The numerical values ​​described in this specification refer to values ​​obtained by the methods described in the Examples below.

[0013] In this specification, the terminally modified polyimide resin (A) may be abbreviated as "polyimide resin (A)," and the curable resin composition may be abbreviated as "the present composition." In this specification, the term "cured product" refers to a state in which the composition has been cured to the extent that further heating does not substantially promote the curing reaction. When the curable resin composition is molded into a desired shape such as a sheet, a portion of the composition may undergo a curing reaction, but the state in which the composition can be cured by further heating is not included in the term "cured product." At the stage of the curable resin composition, some of the components may be in a semi-cured B-stage state.

[0014] [Terminally modified polyimide resin (A)] The terminal-modified polyimide resin (A) has a structure derived from a tetracarboxylic acid half ester (a1), which is a reaction product of a tetracarboxylic acid dianhydride and an alcohol compound, and a diamine (a2), and has a monoamine-modified structure at the molecular chain terminal, in which 40 mol % or more of the diamine (a2) is a dimer diamine. By having 40 mol % or more of the dimer diamine, the lamination property to an LCP substrate after a wet heat test can be improved. The term "polyimide resin (A) having a monoamine-modified structure at the molecular chain terminal" means that the acid anhydride at the polyimide terminal has a structure modified with a monoamine (a3). Note that the term "molecular chain terminal" refers to a repeating structural unit at the terminal of the molecular chain of polyimide resin (A), or a non-repeating structure linked to that terminal. In addition, it also contains amic acid ester structures derived from terminally modified monoamines, which is expected to prevent the reaction between acid anhydrides and dimer diamine oligomers and reduce the formation of amide bonds derived from oligomers with poor heat resistance.

[0015] The terminally modified polyimide resin (A) preferably has a repeating unit having a structure represented by the following formula (1). [ka] X in formula (1) 1 is independently a tetravalent tetracarboxylic acid residue for each repeating unit, and X 2 X each independently represents a divalent organic group for each repeating unit, and the divalent organic group contains at least a group derived from a diamine. 1 and imide bonds are bonded together to form two imide rings.

[0016] In this specification, the term "tetracarboxylic acid residue" refers to a group derived from a tetracarboxylic acid and a tetracarboxylic acid derivative such as a tetracarboxylic acid dianhydride or a tetracarboxylic acid diester (hereinafter, these are referred to as "tetracarboxylic acids"). In the above formula (1), the term "organic group" refers to a group derived from an organic compound having a functional group that reacts with a tetracarboxylic acid. An imide bond is obtained by the reaction of a tetracarboxylic acid with the organic compound.

[0017] An "imido bond" is defined as a bond consisting of one nitrogen atom and two carbonyl bonds (C=O), and is defined as the bond between the imido bond and X in formula (1). 1 are bonded to each other to form an imide ring. An "imide ring" is a ring having an imide bond, and the number of elements forming one ring is 4 or more and 7 or less, preferably 5 or 6. The imide ring may be condensed with another ring. Furthermore, an "acid anhydride group" refers to a group represented by -C(=O)-OC(=O)-, and an "acid anhydride ring" refers to a ring formed by bonding an acid anhydride group and a carbon element.

[0018] <Tetracarboxylic acid half ester (a1)> The tetracarboxylic acid half ester (a1) is composed of a tetracarboxylic acid dianhydride and an alcohol compound. In other words, it is a reaction product of the tetracarboxylic acid dianhydride and the alcohol compound. By using the tetracarboxylic acid half ester (a1), an amic acid ester structure is introduced into the polyimide resin, preventing the reaction between the acid anhydride and the dimer diamine oligomer and suppressing the formation of amide bonds derived from the oligomer, which has poor heat resistance. As a result, the thermal stability of the polyimide resin is improved, and the insulation reliability after heat cycling is improved.

[0019] (Tetracarboxylic acid dianhydride) The tetracarboxylic dianhydride is represented by X in the general formula (1). 1 As described above, X in general formula (1) 1 is a tetravalent tetracarboxylic acid residue, each of which may have an independent structure for each repeating unit. The tetracarboxylic acid dianhydride used in the present invention is not particularly limited. Preferred tetracarboxylic acid dianhydrides include aromatic tetracarboxylic acid dianhydrides containing an aromatic group, aliphatic tetracarboxylic acid dianhydrides containing an aliphatic group, and tetracarboxylic acid dianhydrides containing an aromatic group and an aliphatic group. X 1 Heteroatoms such as nitrogen, oxygen, sulfur, selenium, fluorine, chlorine, and bromine may be contained therein. The tetracarboxylic acids may be used alone or in combination of two or more. The above-mentioned examples of monomers may also have a substituent, as appropriate. Examples of the substituent include an alkyl group, a halogen atom, a nitro group, and a cyano group. The acid anhydrides may be used alone or in combination of two or more.

[0020] Examples of aromatic tetracarboxylic acids include pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and diphthalic dianhydride represented by the following general formula (2): [ka] X in the formula 5 represents a divalent organic group which may have a substituent (for example, a hydrocarbon group having 1 to 10 carbon atoms), -O-, -CO-, -SO2-, -S-, -SO2-, -CONH-, -COO-, or a linking group such as -OCO-, -C(CF3)2-, -COO-Z-OCO-, or -O-Ph-C(CH3)2-Ph-O-. The Z may be, for example, -C6H4-, -(CH2) n Examples of the substituent include -, -CH2-CH(-OC(=O)-CH3)-CH2-. These may contain a substituent. Examples of the substituent include an alkyl group, a halogen, and a carbonyl group. The same applies to the tetracarboxylic acid described below. Specific examples include 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, p-phenylenebis(trimellitic acid monoester acid anhydride), and ethylene glycol bisanhydrotrimellitate.

[0021] From the viewpoint of effectively improving lamination onto an LCP substrate at low temperatures and further improving insulation reliability after heat cycles, X in general formula (1) 1 At least a portion of X has an aliphatic group 1 It is preferable that X is a. 1 a has only to have an aliphatic group, and may also contain an aromatic group.

[0022] Tetracarboxylic acids having an aliphatic group include chain hydrocarbon structures and / or alicyclic hydrocarbon structures which may contain an aromatic group. The "chain hydrocarbon structure" refers to a linear hydrocarbon structure and / or a branched hydrocarbon structure which may contain an unsaturated bond. The "alicyclic hydrocarbon structure" refers to an alicyclic hydrocarbon which may contain an unsaturated bond, and may be monocyclic or polycyclic. These may contain a substituent. Tetracarboxylic acids having an aliphatic group and tetracarboxylic acids not having an aliphatic group may be used in combination. The ratio of tetracarboxylic acids having an aliphatic group in the total of all tetracarboxylic acids (100 mol%) is preferably 40 mol% or more, and more preferably 55 mol% or more. When the content is within this range, the lamination properties onto the LCP substrate can be effectively improved.

[0023] Specific examples of tetracarboxylic acids having an aliphatic group include tetracarboxylic dianhydrides having a chain hydrocarbon structure, such as 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 1,2,4,5-pentanetetracarboxylic acid, 1,2,3,4-hexanetetracarboxylic acid, and 1,2,5,6-hexanetetracarboxylic acid. Also, cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, 1-carboxymethyl-2,3,5-cyclopentanetricarboxylic acid, 3-carboxymethyl-1,2,4-cyclopentanetricarboxylic acid, rel-dicyclohexyl-3,3',4,4'-tetracarboxylic acid, tricyclo[4.2.2.02,5]dec-9-ene-3,4,7,8-tetracarboxylic acid, 5-carboxymethylbicyclo[2.2.1]heptane-2,3,6-tricarboxylic acid, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid, and bicyclo[2.2.2]oct-7-ene-2,3,6 Cyclo-, bicyclo-, and tricyclotetracarboxylic acids such as 7,8-diphenylbicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid, bicyclo[3.3.0]octane-2,4,6,7-tetracarboxylic acid, 7,8-diphenylbicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid, 4,8-diphenyl-1,5-diazabicyclooctane-2,3,6,7-tetracarboxylic acid, 9-oxatricyclo[4.2.1.02,5]nonane-3,4,7,8-tetracarboxylic acid, and 9,14-dioxopentacyclo[8.2.11,11.14,7.02,10.03,8]tetradecane-5,6,12,13-tetracarboxylic acid; spiro-ring-containing tetracarboxylic acids such as 2,8-dioxaspiro[4.5]decane-1,3,7,9-tetracarboxylic acid; and 5-(2,5-dioxotetrahydrofuryl). Examples include tetracarboxylic acid dianhydrides having an alicyclic hydrocarbon structure, such as 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione, and 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride.

[0024] From the viewpoint of more effectively improving lamination onto the LCP substrate after the moist heat test, X having an aliphatic group 1It is preferred that a has a structure S that satisfies at least one of the following (I) and (II): (I) X constituting the imide ring in general formula (1) 1 is X 1 At least one of the carbon atoms in a is a carbon atom of X constituting the other imide ring. 1 At least one of the carbon atoms in a is directly bonded to the other. (II) X constituting each of the two imide rings in general formula (1) 1 is X 1 At least one of the carbon atoms in a independently satisfies either one of the following conditions: it is directly bonded to a chain hydrocarbon structure or an alicyclic hydrocarbon structure, or it is one of the constituent elements of the alicyclic hydrocarbon structure. Specific examples of compounds that satisfy the above condition (I) include chemical formulas (Ia) to (Id). Note that chemical formulas (Ib) to (Id) also satisfy the above condition (II). In the formulas, * indicates the bonding site with the imide group. [ka]

[0025] Specific examples that satisfy the above (II) include chemical formulas (II-a) to (II-v).

[0026] [ka]

[0027] X forms an imide ring 1 X having structure S, where the carbon in a is directly connected to a chain hydrocarbon structure 1 An example of a is a compound represented by the chemical formula (II-a). X forming an imide ring 1 X having the structure S, in which the carbon in the molecule is one of the constituent elements of an alicyclic hydrocarbon structure 1 An example of a is a compound represented by the chemical formula (II-b). 1 The carbon atom of a is directly bonded to the alicyclic hydrocarbon structure, and the carbon atom of X that forms the other imide ring 1X having structure S, in which the carbon in a is one of the constituent elements of an alicyclic hydrocarbon structure 1 An example of a is represented by chemical formula (II-c). Note that the two imide rings may each independently satisfy at least one of the above conditions (I) and (II), and may contain an aromatic ring as shown in chemical formula (II-d).

[0028] X having an aliphatic group 1 The proportion of a is the ratio of X that constitutes the polyimide resin (A). 1 In 100 mol %, the content is preferably 60 to 100 mol %, more preferably 75 to 100 mol %, and even more preferably 85 to 100 mol %. 1 By using 60 to 100 mol % of a, the lamination property to LCP becomes better. 1 The proportion of a is determined by the ratio of X to X among the raw material monomers used in synthesizing polyimide resin (A). 1 X having an aliphatic group relative to 100 mol% of all monomers that become residues 1 It can be calculated from the content (mol%) of the monomer where a is the residue. Usually, the ratio of the monomers used during synthesis is the same as the constituent ratio in the resin.

[0029] (alcohol compounds) The alcohol compound is used to modify the tetracarboxylic dianhydride. It is not particularly limited as long as it has a hydroxyl group, and examples thereof include methanol, ethanol, isopropyl alcohol, propanol, butanol, 2-butanol, 2-methyl-1-propanol, ethyl-1-butanol, t-butanol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, 4-methyl-1-pentanol, cyclopentanol, 1-hexanol, 2-ethyl-1-hexanol, 3-hexanol, 1-heptanol, 2-heptanol, 4-heptanol, diisobutylcarbinol, 1-octanol, 2-octanol, and 4-octanol. Ethanol, isopropyl alcohol, and t-butanol are preferred due to their excellent reactivity with tetracarboxylic dianhydrides. Excellent reactivity with tetracarboxylic dianhydrides improves the imide ring closure rate, thereby improving the thermal stability of the polyimide resin.

[0030] <Diamine (a2)> The diamine (a2) is represented by X in the general formula (1). 2 In general formula (1), X 2 As described above, each repeating unit may have an independent structure and each group is a divalent organic group. At least 40 mol % of the diamine (a2) is a dimer diamine.

[0031] Dimer diamines can be obtained, for example, by converting the carboxyl groups of dimer acids to amino groups. For example, dimer acids can be obtained by dimerizing natural fatty acids such as soybean oil fatty acids, tall oil fatty acids, and rapeseed oil fatty acids, and unsaturated fatty acids purified from these, such as linolenic acid, linoleic acid, oleic acid, and erucic acid. The unsaturated bonds may be hydrogenated as needed to reduce the degree of unsaturation. Dimer diamines with a reduced degree of unsaturation are advantageous in terms of oxidation resistance (particularly coloration at high temperatures) and suppression of gelation during synthesis.

[0032] The dimer acid is preferably a compound having 20 to 60 carbon atoms, more preferably a compound having 24 to 56 carbon atoms, even more preferably a compound having 28 to 48 carbon atoms, and particularly preferably a compound having 36 to 44 carbon atoms. Dicarboxylic acid compounds having a branched structure obtained by subjecting a fatty acid to a Diels-Alder reaction are preferred. The branched structure is preferably an aliphatic chain or a cyclic structure, more preferably a cyclic structure. The cyclic structure is preferably one or more aromatic rings or an alicyclic structure, more preferably an alicyclic structure. When there are two cyclic structures, the two rings may be independent or continuous. One or more dimer diamine and dimer diisocyanate compounds can be used. The alicyclic structure may have one or more double bonds in the ring, or may have no double bond. Methods for converting the carboxy group of a dimer acid to an amino group include, for example, amidating the carboxylic acid, converting it to an amine by Hofmann rearrangement, and then distilling and purifying the resulting mixture. The carboxy group of the dimer acid can be converted into a diisocyanate group, for example, by converting a carboxylic acid into an isocyanate group through Curtius rearrangement.

[0033] The amino group in the dimer diamine may be directly bonded to the ring structure, but from the viewpoint of improving solubility and flexibility, it is preferable that the amino group be bonded to the ring structure via an aliphatic chain. The number of carbon atoms between the amino group and the ring structure is preferably 2 to 25. A suitable example of the aliphatic chain is a chain hydrocarbon group such as an alkylene group. A suitable example is a compound in which the two amino groups are each bonded to the ring structure via an alkylene group.

[0034] Specific examples of dimer acids (polybasic acids) for obtaining dimer diamine or dimer diisocyanate include the following chemical formulas (d1) to (d4). These are just examples, and the dimer acid is not limited to the following structures.

[0035] [ka] [ka] [ka] [ka]

[0036] The dimer diamine is preferably a compound having 20 to 60 carbon atoms, more preferably a compound having 24 to 56 carbon atoms, even more preferably a compound having 28 to 48 carbon atoms, and still more preferably a compound having 36 to 44 carbon atoms. Such carbon numbers are preferred from the viewpoint of ease of availability.

[0037] Commercially available dimer diamine products include, for example, "Priamine 1071," "Priamine 1073," "Priamine 1074," and "Priamine 1075" manufactured by Croda Japan, and "Versamin 551" manufactured by BASF Japan.

[0038] The proportion of dimer diamine is 40 mol % or more, and may be 100 mol %, based on 100 mol % of diamine (a2). A more preferred range is 60 to 100 mol %, and an even more preferred range is 80 to 100 mol %. The proportion of dimer diamine can be determined from the content (mass %) of dimer diamine in 100 mass % of diamine (a2) among the raw material monomers used in synthesizing the polyimide resin (A). Usually, the ratio of the monomers used in the synthesis is the same as the constituent ratio in the resin.

[0039] X in general formula (1) 2 Examples of the diamines include those having a phenolic hydroxyl group, which will be described later. 2 Diamines other than the monomers forming d and diamines having a phenolic hydroxyl group can be used as appropriate. Examples include diamine compounds having an aliphatic group (a chain hydrocarbon structure and / or an alicyclic hydrocarbon structure that may contain an unsaturated bond), which may have a substituent, an aromatic ring, and any combination thereof.

[0040] Other diamines include, for example, 1,4-diaminobenzene, 1,3-diaminobenzene, 1,2-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, 2,6-diaminotoluene, 2,4-diaminotoluene, 3,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diamino-1,2- Aromatic diamines such as diphenylethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,3'-diaminodiphenylsulfone, bis(3-amino-4-hydroxyphenyl)hexafluoropropane, bis(3-amino-4-hydroxyphenyl)sulfone, bis(3-amino-4-hydroxyphenyl)propane, bis(3-amino-4-hydroxyphenyl)methylene, bis(3-amino-4-hydroxyphenyl)ether, bis(3-amino-4-hydroxy)biphenyl, 2,2'-ditrifluoromethyl-5,5'-dihydroxyl-4,4'-diaminobiphenyl, bis(3-amino-4-hydroxyphenyl)fluorene, and 2,2'-bis(trifluoromethyl)-5,5'-dihydroxybenzidine; ethylenediamine, 1,3-propane aliphatic diamines such as hexanediamine, 1,4-butanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,9-nonanediamine, 1,12-dodecamethylenediamine, and metaxylenediamine; and alicyclic diamines such as isophoronediamine, norbornanediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, and piperazine.

[0041] <Monoamine (a3)> Examples of the monoamine (a3) ​​include butylamine, hexylamine, isopropylamine, aminopropyltriethoxysilane, aminopropyltrimethoxysilane, amylamine, aniline, aminodecane, aminotridecane, 2-ethylhexylamine, 2-methylallylamine, nonylamine, propargylamine, oleylamine, benzylamine, p-aminophenol, m-aminophenol, norbornenemethylamine, and cysteamine. Among these, p-aminophenol, m-aminophenol, norbornenemethylamine, and cysteamine are preferred from the viewpoint of reactivity.

[0042] <Other monomers> The polyimide resin (A) may contain X within the scope of the present invention. 1 residue, X 2 The polyamine compound may contain residues derived from monomers other than the amino groups. For example, a polyamine compound having three or more amino groups may be used. Examples of polyamine compounds having three or more amino groups include 1,2,4-triaminobenzene and 3,4,4'-triaminodiphenyl ether.

[0043] <Method for producing polyimide resin (A)> The polyimide resin (A) can be produced by various known methods. Specific examples include a method in which a polyimide precursor, a polyamic acid resin or a polyamic acid ester resin, is cyclized by heating to convert it into an imide group. Examples of methods for synthesizing the precursor include a method in which a tetracarboxylic acid half ester (a1) is obtained by reacting a tetracarboxylic acid dianhydride with an alcohol, and then the tetracarboxylic acid half ester (a1) is reacted with a diamine (a2) in the presence of a condensing agent, and a method in which a tetracarboxylic acid dianhydride is reacted with an alcohol to obtain a half ester (a1), and then the remaining dicarboxylic acid is converted into an acid chloride and reacted with a diamine (a2).

[0044] When the monoamine (a3) ​​is introduced into the molecular chain terminal, it may be introduced during the synthesis of the polyamic acid resin or polyamic acid ester resin, or may be introduced after the polyimide resin is obtained.

[0045] Examples of organic solvents used in polymerization include N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, and cresol. Solvents can be used alone or in combination. Aromatic hydrocarbons such as xylene and toluene can also be used in combination.

[0046] The method for imidizing a polyimide precursor to obtain a polyimide resin is not particularly limited, but an example is a method in which the polyimide precursor is heated in a solvent at a temperature of 80 to 400°C for 0.5 to 50 hours. At this time, a catalyst and / or a dehydrating agent may be used as necessary. Examples of reaction catalysts include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine, picoline, and isoquinoline. Examples of dehydrating agents include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as benzoic anhydride.

[0047] The imidization rate (the rate of imide ring formation) is not limited, but from the viewpoint of effectively exhibiting plating solution resistance (alkali resistance and acid resistance), it is preferably 80% or more, more preferably 90% or more, and even more preferably 95 to 100%. The imidization rate can be determined by nuclear magnetic resonance (NMR) analysis, infrared spectroscopy (IR) analysis, etc.

[0048] The weight-average molecular weight (Mw) of the polyimide resin (A) is not particularly limited, but is preferably 10,000 or more, and more preferably 20,000 or more, from the viewpoint of improving the insulation reliability of the cured product after a heat cycle test. The upper limit of Mw is not particularly limited, but is preferably 100,000 or less, and more preferably 50,000 or less, from the viewpoint of easy handling of the solution viscosity.

[0049] [Curable compound (B))] The curable compound (B) is a compound that forms a crosslinked structure by heat curing treatment, and examples thereof include epoxy compounds, cyanate ester compounds, isocyanate group-containing compounds, metal chelate compounds, carbodiimide group-containing compounds, maleimide group-containing compounds, phenolic resins, vinyl group-containing compounds (excluding allyl group-containing compounds and (meth)acryloyl group-containing compounds), allyl group-containing compounds and (meth)acryloyl group-containing compounds, etc. One type may be used alone, or two or more types may be used in combination. From the viewpoint of improving heat resistance, plating solution resistance, and insulation reliability after a heat cycle test, it is preferable to include at least one compound selected from the group consisting of epoxy compounds, cyanate ester compounds, maleimide compounds, vinyl group-containing compounds (excluding allyl group-containing compounds and (meth)acryloyl group-containing compounds), allyl group-containing compounds, and (meth)acryloyl group-containing compounds, among the above compounds.

[0050] The content of the curable compound (B) is preferably 0.5 to 200 parts by mass, more preferably 5 to 99 parts by mass, and even more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the polyimide resin (A). By ensuring that the content of the curable compound (B) is within the above range, excellent heat resistance can be achieved. From the viewpoint of heat resistance, the molecular weight of the curable compound is preferably 100 or more and less than 10,000.

[0051] From the viewpoint of laminate strength, the curable compound (B) preferably contains 30 to 100 mass% in total of epoxy compounds, cyanate ester compounds, maleimide compounds, vinyl group-containing compounds (excluding allyl group-containing compounds and (meth)acryloyl group-containing compounds), allyl group-containing compounds, and (meth)acryloyl group-containing compounds, and more preferably 50 to 100 mass% in total, based on 100 mass% of the curable compound (B).

[0052] From the viewpoint of achieving a balanced improvement in heat resistance, lamination properties with LCP substrates, plating solution resistance, insulation reliability after heat cycle testing, and laser processability after curing, epoxy compounds alone or in combination with one or more of cyanate ester compounds, maleimide compounds, vinyl group-containing compounds (excluding allyl group-containing compounds and (meth)acryloyl group-containing compounds), allyl group-containing compounds, and (meth)acryloyl group-containing compounds are preferred. Also preferred are combinations in which a crosslinking reaction occurs between the curable compounds (B) used in combination.

[0053] (epoxy compounds) The epoxy compound is not particularly limited as long as it has two or more epoxy groups in the molecule. Among epoxy compounds, compounds having an average epoxy group functionality of three or more are preferred from the viewpoint of laminate strength. As the epoxy compound, for example, epoxy resins such as glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, and cyclic aliphatic (alicyclic) epoxy resins can be used.

[0054] Examples of bifunctional epoxy compounds include glycidyl ester epoxy resins such as diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate; cycloaliphatic (alicyclic) epoxy resins such as epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate; and bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, and bisphenol AD ​​epoxy resins.

[0055] Examples of epoxy compounds having an average number of functional groups of 3 or more include tris(glycidyloxyphenyl)methane and tetrakis(glycidyloxyphenyl)ethane, and examples of glycidylamine-type epoxy resins include tetraglycidyldiaminodiphenylmethane, triglycidyl paraaminophenol, triglycidyl meta-aminophenol, tetraglycidyl meta-xylylenediamine, and sorbitol polyglycidyl ether.

[0056] Other examples include epoxy compounds such as cresol novolac epoxy resins, phenol novolac epoxy resins, α-naphthol novolac epoxy resins, bisphenol A novolac epoxy resins, dicyclopentadiene epoxy resins, tetrabromobisphenol A epoxy resins, and brominated phenol novolac epoxy resins.

[0057] The epoxy compound may be one of the above compounds or a combination of two or more of them. From the viewpoint of high adhesiveness, it is preferable to select the epoxy compound from the group consisting of bisphenol A epoxy resin, cresol novolac epoxy resin, phenol novolac epoxy resin, tris(glycidyloxyphenyl)methane, tetrakis(glycidyloxyphenyl)ethane, and tetraglycidylmeta-xylylenediamine.

[0058] (cyanate ester compounds) The cyanate ester compound refers to a compound having two or more cyanate groups. Specific examples include aromatic cyanate ester compounds such as 2,2-bis(4-cyanatephenyl)propane (bisphenol A-type cyanate resin), bis(3,5-dimethyl-4-cyanatephenyl)methane, 2,2-bis(4-cyanatephenyl)ethane, and derivatives thereof. These compounds may be used alone or in combination.

[0059] (Isocyanate group-containing compounds) The isocyanate group-containing compound is not particularly limited as long as it has two or more isocyanate groups in the molecule.

[0060] Specific examples of isocyanate group-containing compounds having two isocyanate groups in one molecule include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisine diisocyanate, 2,4,6-triisocyanate toluene, 2,4,6-triisocyanate toluene, 2,4,6-triisocyanate toluene, 2,4,6-triisocyanate toluene, dianisine diisocyanate ... Aromatic diisocyanates such as ethylene diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4',4"-triphenylmethane triisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexyl Aliphatic diisocyanates such as samethylene diisocyanate, ω,ω'-diisocyanato-1,3-dimethylbenzene, ω,ω'-diisocyanato-1,4-dimethylbenzene, ω,ω'-diisocyanato-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and other aromatic aliphatic diisocyanates, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate [also known as isophorone], alicyclic diisocyanates such as 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,3-bis(isocyanatomethyl)cyclohexane, and 1,4-bis(isocyanatomethyl)cyclohexane.

[0061] Furthermore, examples of the isocyanate group-containing compound having three isocyanate groups in one molecule include aromatic polyisocyanates, aliphatic polyisocyanates such as lysine triisocyanate, araliphatic polyisocyanates, and alicyclic polyisocyanates, as well as the trimethylolpropane adducts of the diisocyanates described above, biuret products obtained by reaction with water, and trimers having an isocyanurate ring.

[0062] The isocyanate group-containing compound may be a blocked isocyanate group-containing compound in which the isocyanate group in the various isocyanate group-containing compounds exemplified above is protected with ε-caprolactam, MEK oxime, or the like. Specific examples include compounds in which the isocyanate group of the isocyanate group-containing compound is blocked with ε-caprolactam, methyl ethyl ketone (hereinafter referred to as MEK) oxime, cyclohexanone oxime, pyrazole, phenol, or the like. In particular, when a hexamethylene diisocyanate trimer having an isocyanurate ring and blocked with MEK oxime or pyrazole is used in the present invention, it is highly preferred because it has excellent adhesive strength to polyimide and copper and excellent heat resistance. Furthermore, from the viewpoint of heat resistance, it is preferable for the compound to have three or more isocyanate groups.

[0063] (metal chelate compounds) A metal chelate compound is an organometallic compound consisting of a metal and an organic substance, which reacts with the reactive functional group of the polyimide resin (A) or the crosslinkable functional group of the curable compound (B) to form a crosslink. The type of organometallic compound is not particularly limited, but examples include organoaluminum compounds, organotitanium compounds, and organozirconium compounds. The bond between the metal and the organic substance may be a metal-oxygen bond, but is not limited to a metal-carbon bond. Furthermore, from the viewpoint of heat resistance, it is preferable that the number of functional groups (the number of groups capable of coordinate bonding) be 3 or more.

[0064] The organoaluminum compound is preferably an aluminum metal chelate compound. Examples of the aluminum metal chelate compound include ethyl acetoacetate aluminum diisopropylate, aluminum tris(ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bis(ethyl acetoacetate), aluminum tris(acetylacetate), aluminum monoacetylacetate bis(ethyl acetoacetate), aluminum di-n-butoxide monomethyl acetoacetate, aluminum diisobutoxide monomethyl acetoacetate, aluminum di-sec-butoxide monomethyl acetoacetate, aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum sec-butylate, and aluminum ethylate.

[0065] The organic titanium compound is preferably a titanium metal chelate compound. Examples of titanium metal chelate compounds include titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, titanium octylene glycolate, titanium ethylacetoacetate, titanium-1,3-propanedioxybis(ethylacetoacetate), polytitanium acetylacetonate, tetraisopropyl titanate, tetra-normal butyl titanate, butyl titanate dimer, tetraoctyl titanate, diamyl titanate, tetratertiary butyl titanate, tetrastearyl titanate, titanium isostearate, tri-n-butoxytitanium monostearate, di-i-propoxytitanium distearate, titanium stearate, di-i-propoxytitanium diisostearate, (2-n-butoxycarbonylbenzoyloxy)tributoxytitanium, etc. The organic zirconium compound is preferably a zirconium metal chelate compound. Examples of the zirconium metal chelate compound include zirconium tetraacetylacetonate, zirconium tributoxyacetylacetonate, zirconium monobutoxyacetylacetonate bis(ethylacetoacetate), zirconium dibutoxybis(ethylacetoacetate), zirconium tetraacetylacetonate, normal propyl zirconate, normal butyl zirconate, zirconium stearate, and zirconium octylate. Among these, organic titanium compounds and organic zirconium compounds are preferred in terms of thermosetting reactivity.

[0066] (Carbodiimide group-containing compound) The carbodiimide group-containing compound is not particularly limited as long as it has two or more carbodiimide groups in the molecule. Examples of the carbodiimide group-containing compound include Carbodilite V-01, V-03, V-05, V-07, and V-09 (Nisshinbo Chemical Inc.), and cyclic carbodiimide (Teijin Limited). From the viewpoint of heat resistance, compounds having an average of three or more carbodiimide groups in one molecule are preferred.

[0067] (Maleimide compounds) The maleimide compound may be a polyfunctional maleimide obtained by reacting a polyfunctional amine with maleic anhydride. Examples of polyfunctional amines include isophoronediamine, dicyclohexylmethane-4,4'-diamine, and Huntsman Corporation's Jeffamine D-230, HK-511, D-400, XTJ-582, D-2000, XTJ-578, XTJ-509, XTJ-510, T-403, and T-5000, which have terminally aminated polypropylene glycol backbones, and XTJ-500, XTJ-501, XTJ-502, XTJ-504, XTJ-511, XTJ-512, and XTJ-590, which have terminally aminated ethylene glycol backbones, and XTJ-542, XTJ-533, XTJ-536, XTJ-548, and XTJ-559, which have terminally aminated polytetramethylene glycol backbones.

[0068] Maleimide compounds include 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, p-phenylene bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, bis-(3-ethyl-5-methyl-4-maleimidophenyl)methane, 4-methyl-1,3-phenylene bismaleimide, N,N'-ethylene dimaleimide, N,N'-hexamethylene dimaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, 3,3'-dimethyl-5,5'-diethyl- Resins with two maleimide groups in the molecule, such as 4,4'-diphenylmethane bismaleimide, bisphenol A diphenyl ether bismaleimide, biphenyl aralkyl maleimide, polyphenylmethane maleimide (CAS NO: 67784-74-1, reaction product of a polymer consisting of formaldehyde and aniline with maleic anhydride), N,N'-(toluene-2,6-diyl) bismaleimide, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene , 1,3-bis(4-maleimidophenoxy)benzene, N,N'-ethylene bismaleimide, N,N'-trimethylene bismaleimide, N,N'-propylene bismaleimide, N,N'-tetramethylene bismaleimide, N,N'-pentamethylene bismaleimide, N,N'-(1,3-pentanediyl)bis(maleinimide), N,N'-hexamethylene bismaleimide, N,N'-(1,7-heptanediyl)bismaleimide, N,N'-(1,8-octanediyl)bismaleimide, N,N'-(1,9-notanediyl)bismaleimide , N,N'-(1,10-decanediyl)bismaleimide, N,N'-(1,11-undecanediyl)bismaleimide, N,N'-(1,12-dodecanediyl)bismaleimide, N,N'-[(1,4-phenylene)bismethylene]bismaleimide, N,N'-[(1,2-phenylene)bismethylene]bismaleimide, N,N'-[(1,3-phenylene)bismethylene]bismaleimide, 1,6'-bismaleimido-(2,2,4-trimethyl)hexane, N,N'-[(methylimino)bis(4,1-phenylene)]bismaleimide, N,N'-(2-hydroxypropane-1,3-diylbisiminobiscarbonylbisethylene)bismaleimide, N,N'-(dithiobisethylene)bismaleimide, N,N'-[hexamethylenebis(iminocarbonylmethylene)]bismaleimide, N,N'-carbonylbis(1,4-phenylene)bismaleimide, N,N',N' '-[Nitrilotris(ethylene)]trismaleimide, N,N',N''-[Nitrilotris(4,1-phenylene)]trismaleimide, N,N'-[p-phenylenebis(oxy-p-phenylene)]bismaleimide, N,N'-[methylenebis(oxy)bis(2-methyl-1,4-phenylene)]bismaleimide, N,N'-[methylenebis(oxy-p-phenylene)]bis(maleimide)N,N'-[dimethylsilylenebis[(4,1-phenylene) (1,3,4-oxadiazole-5,2-diyl)(4,1-phenylene)]]bismaleimide, N,N'-[(1,3-phenylene)bisoxybis(3,1-phenylene)]bismaleimide, 1,1'-[3'-oxospiro[9H-xanthene-9,1'(3'H)-isobenzofuran]-3,6-diyl]bis(1H-pyrrole-2,5-dione), N,N'-(3,3'-dichlorobiphenyl-4,4'-diyl)bismaleimide, N,N'-(3,3' -dimethylbiphenyl-4,4'-diyl)bismaleimide, N,N'-(3,3'-dimethoxybiphenyl-4,4'-diyl)bismaleimide, N,N'-[methylenebis(2-ethyl-4,1-phenylene)]bismaleimide, N,N'-[methylenebis(2,6-diethyl-4,1-phenylene)]bismaleimide, N,N'-[methylenebis(2-bromo-6-ethyl-4,1-phenylene)]bismaleimide, N,N'-[methylenebis(2-methyl-4, 1-phenylene)]bismaleimide, N,N'-[ethylenebis(oxyethylene)]bismaleimide, N,N'-[sulfonylbis(4,1-phenylene)bis(oxy)bis(4,1-phenylene)]bismaleimide, N,N'-[naphthalene-2,7-diylbis(oxy)bis(4,1-phenylene)]bismaleimide, N,N'-[p-phenylenebis(oxy-p-phenylene)]bismaleimide, N,N'-[(1,3-phenylene)bisoxybis(3,1-phenylene)]bismaleimide, N,N'-(3,6,9-trioxaundecane-1,11-diyl)bismaleimide, N,N'-[isopropylidenebis[p-phenyleneoxycarbonyl(m-phenylene)]]bismaleimide, N,N'-[isopropylidenebis[p-phenyleneoxycarbonyl(p-phenylene)]]bismaleimide, N,N'-[isopropylidenebis[(2,6-dichlorobenzene-4,1-diyl)oxycarbonyl(p-phenylene)]]bismaleimide, N,N'-[(phenylimino)bis N,N'-[azobis(4,1-phenylene)]bismaleimide, N,N'-[1,3,4-oxadiazole-2,5-diylbis(4,1-phenylene)]bismaleimide, 2,6-bis[4-(maleimido-N-yl)phenoxy]benzonitrile, N,N'-[1,3,4-oxadiazole-2,5-diylbis(3,1-phenylene)]bismaleimide, N,N'-[bis[9-oxo-9H-9-phospha(V)-10-oxaphenanthrene-9-yl]methylenebis (p-phenylene)] bismaleimide, N,N'-[hexafluoroisopropylidenebis[p-phenyleneoxycarbonyl(m-phenylene)]] bismaleimide, N,N'-[carbonylbis[(4,1-phenylene)thio(4,1-phenylene)]] bismaleimide, N,N'-carbonylbis(p-phenyleneoxyp-phenylene) bismaleimide, N,N'-[5-tert-butyl-1,3-phenylenebis[(1,3,4-oxadiazole-5,2-diyl)(4,1-phenylene)]] bismaleimide, N,N' -[Cyclohexylidenebis(4,1-phenylene)]bismaleimide, N,N'-[methylenebis(oxy)bis(2-methyl-1,4-phenylene)]bismaleimide, N,N'-[5-[2-[5-(dimethylamino)-1-naphthylsulfonylamino]ethylcarbamoyl]-1,3-phenylene]bismaleimide, N,N'-(oxybisethylene)bismaleimide, N,N'-[dithiobis(m-phenylene)]bismaleimide, N,N'-(3,6,9-trioxaundecane-1,11-diyl)bismaleimide, N,Examples of polyfunctional maleimides include N'-(ethylenebis-p-phenylene)bismaleimide, BMI-689, BMI-1500, BMI-1700, BMI-3000, BMI-5000, and BMI-9000 manufactured by Designer Molecules, and ODA-BMI and BAFBMI manufactured by JFE Chemical Corporation.

[0069] When the maleimide compound is crosslinked by radicals, a radical polymerization initiator can be added. Specific examples include azo compounds and organic peroxides. The polymerization initiators can be used alone or in combination of two or more. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]. Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl)peroxydicarbonate, t-butylperoxy 2-ethylhexanoate, t-butylperoxyneodecanoate, t-butylperoxypivalate, (3,5,5-trimethylhexanoyl)peroxide, dipropionyl peroxide, and diacetyl peroxide.

[0070] (Allyl group-containing compounds) The allyl group-containing compound may be either monofunctional or polyfunctional. Examples of monofunctional allyl compounds include (meth)allyl alcohol. Examples of polyfunctional allyl compounds include triallyl isocyanurate, trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether, tetraallyloxyethane, polyallylsucrose, di(meth)allyl phthalate, tri(meth)allyl isocyanurate, and tri(meth)allyl cyanurate. Other examples include the following compounds: [ka]

[0071] (vinyl group-containing compound) The vinyl group-containing compound is a compound having a carbon-carbon unsaturated double bond, excluding allyl group-containing compounds and (meth)acryloyl group-containing compounds, and may be monofunctional or polyfunctional. Examples of monofunctional vinyl compounds include styrene, vinyltoluene, N-vinylpyrrolidone, N-vinylcaprolactam, vinylimidazole, and vinylpyridine. Examples of polyfunctional vinyl compounds include vinyl ethers such as hexanediol dinorbornene carboxylate, vinylbenzyl-modified polyphenylene ether, pentaerythritol tetranorbornene carboxylate, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, and cyclohexanediol divinyl ether, and divinylbenzene. Among these, vinyl group-containing polyphenylene ether is particularly preferred.

[0072] ((Meth)acryloyl group-containing compound) The (meth)acryloyl group-containing compound may be monofunctional or polyfunctional, and examples thereof include monofunctional (meth)acrylamide compounds, polyfunctional (meth)acrylamide compounds, monofunctional (meth)acrylates, and polyfunctional (meth)acrylates.

[0073] Examples of monofunctional (meth)acrylamide compounds include diacetone (meth)acrylamide, isobutoxymethyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, t-octyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, (meth)acryloylmorpholine, acrylamido-2-methylpropanesulfonic acid, and N-isopropyl (meth)acrylamide. Examples of polyfunctional (meth)acrylamide compounds include N,N'-diacryloyl-4,7,10-trioxa-1,13-tridecanediamine, N,N',N''-triacryloyldiethylenetriamine, N,N',N'',N'''-tetraacryloyltriethylenetetramine, and N,N'-{[2-acrylamido-2-[(3-acrylamidopropoxy)methyl]propane-1,3-diyl)bis(oxy)]bis(propane-1,3-diyl)}diacrylamide.

[0074] Monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, cyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, benzyl (meth)acrylate, (meth)acrylates of phenol alkylene oxide adducts, and p-cumylphenol alkylene oxide adducts. (meth)acrylate, (meth)acrylate of o-phenylphenol alkylene oxide adduct, (meth)acrylate of nonylphenol alkylene oxide adduct, 2-methoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, (meth)acrylate of alkylene oxide adduct of 2-ethylhexyl alcohol, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (2-isobutyl-2-methyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (1,4-dioxaspiro[4,5]decan-2-yl)methyl (meth)acrylate, glycidyl (meth)acrylate, 3,Examples include 4-epoxycyclohexylmethyl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, 2-(meth)acryloyloxyethyl isocyanate, allyl (meth)acrylate, N-(meth)acryloyloxyethyl hexahydrophthalimide, N-(meth)acryloyloxyethyl tetrahydrophthalimide, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl succinic acid, ω-carboxy-polycaprolactone mono(meth)acrylate, 2-(meth)acryloyloxyethyl acid phosphate, 3-(meth)acryloyloxypropyl trimethoxysilane, 3-(meth)acryloyloxypropyl dimethoxymethylsilane, 3-(meth)acryloyloxypropyl triethoxysilane, and 2-(meth)acryloyloxyethyl acid phosphate. In the alkylene oxide adduct, examples of the alkylene oxide include ethylene oxide and propylene oxide.

[0075] Polyfunctional (meth)acrylates include methacrylate group-containing polyphenylene ether, di(meth)acrylates of aliphatic diols such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate; Di(meth)acrylates of alicyclic diols such as cyclohexanedimethylol di(meth)acrylate and tricyclodecanedimethylol di(meth)acrylate; alkylene glycol di(meth)acrylates such as diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate; Esterification reaction product of neopentyl glycol, hydroxypivalic acid, and (meth)acrylic acid (hereinafter referred to as "hydroxypivalic acid neopentyl glycol di(meth)acrylate"), caprolactone-modified hydroxypivalic acid neopentyl glycol di(meth)acrylate; Di(meth)acrylates of alkylene oxide adducts of bisphenol compounds, such as di(meth)acrylates of alkylene oxide adducts of bisphenol A; Di(meth)acrylates of hydrogenated bisphenol compounds such as di(meth)acrylate of hydrogenated bisphenol A; poly(meth)acrylates of alkylene oxide adducts of isocyanuric acid, such as di(meth)acrylates of alkylene oxide adducts of isocyanuric acid, tri(meth)acrylates of alkylene oxide adducts of isocyanuric acid, di(meth)acrylates of alkylene oxide adducts of caprolactone-modified alkylene oxide adducts of isocyanuric acid, and tri(meth)acrylates of alkylene oxide adducts of caprolactone-modified alkylene oxide adducts of isocyanuric acid; Polyol poly(meth)acrylates such as trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri- or tetra(meth)acrylate, and dipentaerythritol penta- or hexa(meth)acrylate; Poly(meth)acrylates of polyol alkylene oxide adducts such as tri(meth)acrylate of trimethylolpropane alkylene oxide adduct, tetra(meth)acrylate of ditrimethylolpropane alkylene oxide adduct, tri- or tetra(meth)acrylate of pentaerythritol alkylene oxide adduct, and penta- or hexa(meth)acrylate of dipentaerythritol alkylene oxide adduct: Urethane (meth)acrylates; Epoxy (meth)acrylates; and An example is polyester (meth)acrylate. In the alkylene oxide adduct, examples of the alkylene oxide include ethylene oxide and propylene oxide.

[0076] ≪Curable resin composition≫ The curable resin composition according to this embodiment (hereinafter also referred to as the present composition) contains a polyimide resin (A) and a curable compound (B). The polyimide resin (A) is preferably contained in an amount of 5 to 99 mass%, more preferably 50 to 95 mass%, of the total of 100 mass% of the polyimide resin (A) and the curable compound (B). By keeping the polyimide resin content within this range, it is possible to improve adhesion to LCP and insulation reliability after heat cycles. It is preferable to form a crosslinked structure between the polyimide resin (A) and the curable compound (B), and the cured product may contain a crosslinked structure between the curable compounds (B).

[0077] Conventionally, LCP substrates are prone to temporary adhesion defects, and a composition that allows lamination at low temperatures and in a short time has been desired. Because this composition has the above-described structure, it exhibits excellent lamination properties to LCP substrates. This is thought to be due to the synergistic effect of the high wettability of the dimer structure. A thermosetting sheet formed from this composition can provide a curable resin composition that exhibits excellent lamination properties to LCP substrates, even at low temperatures of around 90 to 100°C for heating times of around 60 to 120 seconds.

[0078] Furthermore, because this composition has the above-mentioned structure, it produces a cured product that exhibits minimal change in molecular weight even after a heat resistance test at 260°C for 4 hours, and is less susceptible to lifting or peeling between components. Furthermore, because it has excellent storage stability at low temperatures, it also improves the adhesive strength of LCP substrates after a moist heat test. Furthermore, in a cured product of the present composition, excellent performance can be exhibited even during heat cycles due to the effect of the high stability of the above-mentioned skeleton, in terms of plating solution resistance (alkali resistance and acid resistance) and insulation reliability after heat cycle testing.

[0079] The present composition is suitable for various sheets and films, including thermosetting adhesive sheets and thermosetting cover sheets. These are used by laminating a layer formed from the present composition with another substrate or layer. Any known lamination method can be used without limitation. For example, coating methods and lamination methods are available. The lamination method is advantageous in terms of simplicity.

[0080] <Optional ingredients> The composition may contain optional components such as a curing accelerator, an ultraviolet absorber, a filler, and other optional components.

[0081] (curing accelerator) As the curing accelerator, for example, a radical polymerization initiator, a urea-based curing accelerator, a guanidine-based curing accelerator, an imidazole-based curing accelerator, a metal-based curing accelerator, an amine-based curing accelerator, etc. can be used appropriately depending on the curing system. Among them, an imidazole-based curing accelerator is preferred from the viewpoint of improving crosslinking properties. The other curing accelerators may be used alone or in combination of two or more. When a curing accelerator is used, the content thereof is, for example, 0.05 to 0.5 mass %, and preferably 0.1 to 0.3 mass %, relative to 100 mass % of the total nonvolatile content of the curable composition.

[0082] As the radical polymerization initiator, the same radical polymerization initiators as those described above as "radical polymerization initiators that can be used when crosslinking a maleimide compound with radicals" can be used.

[0083] Examples of the urea-based curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, and 3-(2-methylphenyl)-1,1-dimethylurea. Examples thereof include 3-(4-methylphenyl)-1,1-dimethylurea, 3-(3,4-dimethylphenyl)-1,1-dimethylurea, 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, and 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea.

[0084] Examples of guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0085] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-furan. phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 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-phenylimidazole isocyanuric acid adduct, Examples thereof include imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins.

[0086] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organoiron complexes such as iron(III) acetylacetonate, organonickel complexes such as nickel(II) acetylacetonate, and organomanganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0087] Examples of the amine-based curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.

[0088] (ultraviolet absorber) The ultraviolet absorber absorbs ultraviolet light and converts the optical energy of ultraviolet light into thermal energy. When UV laser light is used to form vias in a cured layer obtained by curing a thermosetting sheet such as an adhesive sheet formed from the present composition, the addition of an ultraviolet absorber can adjust the amount of energy applied to the adhesive sheet or cured layer. As a result, laser processability can be improved. The ultraviolet absorber is preferably contained in an amount of 0.1 to 10 mass %, more preferably 0.1 to 5 mass %, based on 100 mass % of the present composition. Note that various wavelengths (ultraviolet light, infrared light, etc.) can be selected for the laser light irradiation on the adhesive sheet or cured layer depending on the application. Furthermore, multiple laser beams may be used as needed.

[0089] Examples of ultraviolet absorbers include benzophenones, benzotriazoles, triazines, salicylic acid esters, and cyanoacrylates. Zinc oxide may also be used. The ultraviolet absorber (C) can be used regardless of whether or not the surface has been treated. Specifically, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-5-chlorobenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, poly-4-(2-acryloxyethoxy)-2-hydroxybenzophenone, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-t-butylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dimethylphenyl)benzotriazole, 2-(2-methyl-4-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-3-methyl-5-t-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-t-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dimethylphenyl)-5-methoxybenzotriazole, 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-5-chlor Examples of suitable esters include 2-(2-hydroxy-5-t-butylphenyl)-5-chlorobenzotriazole, 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyloxy)phenol, phenyl salicylate, p-octylphenyl salicylate, ethyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, and 2,2-bis{[2-cyano-3,3-diphenylacryloyloxy]methyl}propane-1,3-diyl-bis(2-cyano-3,3-diphenylacrylate).

[0090] (filler) From the viewpoint of improving the plating solution resistance of the composition, its insulating reliability after a heat cycle test, and its lamination properties to LCP, the composition preferably contains 3 to 60 mass% of filler, more preferably 5 to 40 mass% of filler, based on 100 mass% of the composition. By including a filler content of 3 mass% or more, the occurrence of cracking, peeling, and other defects due to stress caused by sudden temperature changes during a heat cycle test can be effectively suppressed. Furthermore, by including a specific amount or more of a component that is resistant to corrosion by the plating solution, the occurrence of cracking, peeling, and other defects due to stress caused by sudden temperature changes during a heat cycle test can be effectively suppressed, thereby preventing the intrusion of moisture into cracked or peeled areas and improving insulating reliability. On the other hand, by including a filler content of 60 mass% or less, the proportion of resin components that contribute to adhesion to the adherend is increased, resulting in better lamination properties to LCP substrates.

[0091] The shape of the filler is not particularly limited. Examples include spherical, powdery, fibrous, needle-like, and scale-like shapes. Specific examples of the filler (D) include fluorine fillers: polytetrafluoroethylene powder and modified products thereof, tetrafluoroethylene-perfluoroalkyl vinyl ether powder, tetrafluoroethylene-ethylene powder, tetrafluoroethylene-hexafluoropropylene powder, tetrafluoroethylene-vinylidene fluoride powder, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether powder, polychlorotrifluoroethylene powder, chlorotrifluoroethylene-ethylene powder, chlorotrifluoroethylene-vinylidene fluoride powder, polyvinylidene fluoride powder, and polyvinyl fluoride powder.Further, polyethylene powder, polyacrylate powder, epoxy resin powder, polyamide powder, polyimide powder, polyurethane powder, liquid crystal polymer beads, polysiloxane powder, etc., as well as polymer fillers such as multilayer core-shell structures using silicone, acrylic, styrene butadiene rubber, butadiene rubber, etc.; (poly)phosphate compounds such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium amide phosphate, ammonium amide polyphosphate, carbamate phosphate, and carbamate polyphosphate; organic phosphate ester compounds, phosphazene compounds, phosphonic acid compounds, phosphinic acid compounds such as aluminum diethylphosphinate, aluminum methylethylphosphinate, aluminum diphenylphosphinate, aluminum ethylbutylphosphinate, aluminum methylbutylphosphinate, and aluminum polyethylenephosphinate; phosphine oxide compounds, phosphorane compounds, phosphinic acid compounds, etc. Examples of fillers include phosphorus-based fillers such as sulfonamide compounds; nitrogen-based fillers such as benzoguanamine, melamine, melam, melem, melon, melamine cyanurate, cyanuric acid compounds, isocyanuric acid compounds, triazole-based compounds, tetrazole compounds, diazo compounds, and urea; and inorganic fillers such as crystalline silica, amorphous silica, hollow silica, porous silica, mica, talc, kaolin, clay, hydrotalcite, wollastonite, xonotlite, silicon nitride, boron nitride, aluminum nitride, calcium hydrogen phosphate, calcium phosphate, glass flakes, hydrated glass, calcium titanate, sepiolite, magnesium sulfate, aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, calcium hydroxide, titanium oxide, tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, antimony oxide, nickel oxide, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc borate, and aluminum borate.

[0092] When a cured layer formed from the present composition is applied to an insulating layer of a large-capacity, high-speed substrate, examples of the insulating layer include liquid crystal polymers, fluororesins, modified polyphenylene ethers, glass balloons which are hollow glass bodies, hollow coal ash bodies, shirasu balloons, calcium carbonate, talc, and mixtures thereof.

[0093] From the viewpoint of impact absorption, it is preferable to use fluorine filler, boron nitride, liquid crystal polymer and silica. The fillers may be used alone or in combination.

[0094] The method for adding the filler is not particularly limited, and any conventionally known method can be used. Suitable examples include adding the filler to a polymerization reaction solution before or during polymerization of the polyimide resin (A), kneading the filler into the polyimide resin (A) using a three-roll mill, or preparing a dispersion containing the filler and mixing it with the polyimide resin (A). Furthermore, to disperse the filler well and stabilize the dispersion state, dispersants, thickeners, etc. can also be used within a range that does not affect the physical properties of the thermosetting resin composition.

[0095] (Other optional ingredients) The present composition may contain various additives and other optional components within the scope of the present invention. For example, polyimide resins other than polyimide resin (A) may be used. Any thermoplastic resin may also be used. A catalyst may be included as an optional component to promote crosslinking between the phenolic hydroxyl groups in the polyimide resin (A) and the curable compound (B). Suitable examples of catalysts include imidazole-based, amine-based, and phosphorus-based catalysts. Other examples of catalysts include dyes, pigments (e.g., carbon black), flame retardants, antioxidants, polymerization inhibitors, defoamers, leveling agents, ion scavengers, moisturizers, viscosity modifiers, preservatives, antibacterial agents, antistatic agents, antiblocking agents, ultraviolet absorbers, infrared absorbers, and electromagnetic wave shielding agents.

[0096] (Characteristics of the curable composition) From the viewpoint of insulation reliability after a heat cycle test, the present composition preferably has a glass transition temperature (Tg) in the range of 0 to 70°C after thermal curing at 180°C for 60 minutes. It is more preferably 10 to 60°C. Having a glass transition temperature of 0°C or higher prevents significant collapse of the crosslinked structure in the composition even with extreme environmental temperature cycles, thereby suppressing the flow of metal ions generated from electrodes that cause short-circuiting, resulting in excellent insulation reliability. On the other hand, having a glass transition temperature of 70°C or lower imparts a certain degree of flexibility to the present composition, thereby reducing stress in response to the expansion and contraction of the adherend during extreme environmental temperature cycles, thereby preventing peeling and preventing short-circuiting due to moisture infiltration through gaps created by peeling. Note that the above curing conditions are used to estimate the Tg of the present composition during curing treatment and do not in any way limit the curing conditions for the cured product formed from the present composition.

[0097] (Method for producing curable resin composition) The present composition is obtained by blending the various components. Instead of a polyimide precursor, an imidized polyimide resin (A) is used as a blending component. A solvent can be used as appropriate during blending. The solid content can be, for example, 20 to 60 mass %. The polyimide resin (A) of this embodiment has a dimer structure, and therefore can be easily dissolved in various organic solvents.

[0098] The composition can be in the form of, for example, powder, film, sheet, plate, pellet, paste, or liquid. A liquid or paste thermosetting composition can be easily obtained by adjusting the viscosity using a solvent. A film, sheet, or plate thermosetting composition can be formed, for example, by applying a liquid or paste thermosetting composition and drying it. A powder or pellet thermosetting composition can be obtained, for example, by pulverizing or cutting the film-like or other thermosetting composition into a desired size.

[0099] <Adhesive sheet> The adhesive sheet of the present invention comprises a resin composition layer formed from a curable resin composition on a substrate. The adhesive sheet can be obtained by applying a solvent-containing coating solution of the present composition to one side of a release film, for example, and then removing the liquid medium, such as an organic solvent, and drying at, for example, 40 to 150°C. A double-sided release film-attached adhesive sheet can be obtained by laminating another release film on the surface of the resulting adhesive sheet. Laminating both sides with release films can prevent surface contamination of the adhesive sheet. The adhesive sheet can be isolated by peeling off the release film. The two release films can be the same or different types. Using release films with different release properties can vary the release strength, making it easier to peel them in order. Alternatively, the adhesive sheet can be formed by directly applying the coating solution to the substrate.

[0100] Examples of substrates include resin materials such as polyimide film, polyethylene film, polycarbonate, polyethylene, liquid crystal polymer, phenolic resin, and aramid resin; metal materials such as copper, aluminum, and stainless steel; inorganic materials such as ITO, glass, silicon, and silicon carbide; and composite materials made by combining any of these.

[0101] The coating method can be selected from known methods such as comma coating, knife coating, die coating, lip coating, roll coating, curtain coating, bar coating, gravure printing, flexographic printing, screen printing, dip coating, spray coating, and spin coating.

[0102] The thickness of the adhesive sheet after drying is preferably 5 to 500 μm, more preferably 10 to 100 μm, in order to ensure sufficient adhesiveness and ease of handling.

[0103] The adhesive sheet of the present invention has excellent heat resistance and lamination properties with LCP substrates, making it suitable as an adhesive sheet for flexible printed wiring boards, which require excellent heat resistance and low dielectric properties. Because it exhibits excellent adhesion after curing, it is suitable as an adhesive sheet for bonding various materials (resin layers, metal layers, inorganic layers such as ITO, composite layers, etc.). For example, it is suitable as an adhesive sheet for copper-clad laminates and as a bonding material for components such as electronic circuit boards and electronic components. Copper-clad laminates (CCLs) require a process of electrolytic copper plating on the copper foil surface, removing the resist layer, and then etching with an alkaline or other plating solution. The resin composition layer of the adhesive sheet has excellent plating solution resistance, making it suitable as an adhesive sheet for copper-clad laminates.

[0104] By blending a conductive filler into the curable resin composition, the composition may be used as a conductive adhesive sheet. Furthermore, by using a thermally conductive filler as the filler, the composition can be used in a wide range of applications requiring heat dissipation. For example, by utilizing the moldability of the resin composition, the composition can be suitably used as a heat dissipation component of a desired shape. It is particularly useful as a heat dissipation adhesive or heat dissipation sheet for battery exterior materials and for electronic devices (smartphones, tablet devices, etc.) that cannot be equipped with fans or heat sinks due to their small size and lightness. Furthermore, a cured product of the composition is suitable as an adhesive layer between a heat generating element and a heat sink or as a heat spreader. It can also be used as a heat dissipation layer that covers one or more electronic components mounted on a substrate.

[0105] ≪Cured product≫ The cured product of the present invention can be obtained by subjecting the curable resin composition to a heat curing treatment. The curable resin composition is the present composition described above.

[0106] (Method of producing cured product) For example, a method can be exemplified in which the thermosetting composition is molded into a desired shape such as a sheet and then subjected to a heat curing treatment. A molded product such as a sheet of the thermosetting composition can be easily obtained by applying a thermosetting composition containing a solvent and drying it. The molded product is then heat cured to form a cured product. The molding and curing may occur simultaneously. The sheet-shaped cured product is also called a cured layer.

[0107] The heat curing temperature may be appropriately selected depending on the type of curable composition (B). For example, a method of heat treatment at a temperature of 150 to 230°C for 30 to 180 minutes can be exemplified. During heat curing, pressure can be applied (for example, 5 MPa) for thermocompression bonding, if necessary. The heat curing treatment forms a crosslinked structure in the composition, resulting in a three-dimensionally crosslinked cured product.

[0108] The polyimide resin (A) of this composition has excellent electrical insulating properties, allowing it to provide a cured product with excellent insulating properties. For example, it is suitable for use as a material for forming an insulating layer on a circuit board (including a coverlay layer for a printed wiring board, an interlayer insulating layer for a built-up board, a bonding sheet, etc.). It is also suitable for use as an insulating member for electronic components. Examples of electronic components include power modules such as power semiconductor devices, LEDs, and inverter devices, and it is suitable for use as an insulating layer for substrates, semiconductor chip packages, underfill materials, adhesives, etc. It can also be used as a thermosetting composition for copper-clad laminates, a bonding sheet for forming wiring boards, a cover coat for flexible substrates, a prepreg, etc. Furthermore, the cured product has excellent laser processability, making it suitable for applications in forming openings such as vias and patterns. It can also be used as an adhesive layer for carrier tapes for TBA tapes and COF tapes.

[0109] ≪Substrate with cured material≫ The substrate with the cured product is a substrate having the cured product. The cured product may be formed using an adhesive sheet or may be formed directly on a substrate. Examples of the substrate with the cured product include a printed wiring board.

[0110] Printed wiring boards can be manufactured, for example, by processing the copper foil in a copper-clad laminate by etching or the like, forming a signal circuit or the like on the resulting substrate, laminating the resulting substrate and cover film via an adhesive sheet, and bonding them by thermosetting. Flexible printed wiring boards can also be manufactured, for example, by forming a conductor pattern on an insulating flexible film, forming a protective film on top of the conductor pattern via the adhesive sheet, and thermocompression bonding. Examples of flexible films include polyester, polyimide, liquid crystal polymer, and PTFE film. Conductive patterns can be formed by printing techniques, sputtering, or plating.

[0111] A via hole may be formed in the cured layer of the present composition formed on one or both sides of a printed wiring board by drilling, laser processing, or the like, and filled with a conductive agent. Alternatively, a circuit layer may be formed on an interlayer insulating layer formed from the cured product of the present composition. The cured product of the present composition has excellent plating resistance, making it suitable for the production of multilayer printed wiring boards. [Example]

[0112] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples as long as it does not deviate from the spirit of the present invention. Unless otherwise specified, "%" and "parts" are based on mass.

[0113] (i) Measurement of weight average molecular weight (Mw) Mw was measured using a Showa Denko GPC (gel permeation chromatography) "GPC-101." The solvent was THF (tetrahydrofuran), and two "KF-805L" (Showa Denko GPC column: 8 mm ID x 300 mm size) columns connected in series were used. The sample concentration was 1% by mass, the flow rate was 1.0 mL / min, the pressure was 3.8 MPa, and the column temperature was 40°C. Mw was determined in polystyrene equivalent terms. Data analysis was performed using the manufacturer's built-in software to calculate the calibration curve, molecular weight, and peak area, and Mw was calculated for the retention time range of 17.9 to 30.0 minutes. <Synthesis of polyimide resin> [Synthesis Example 1] Polyimide resin (A1) A 1L separable flask equipped with an oil bath and a stirrer was charged with nitrogen gas. 100 g of cyclohexanone was added, followed by 44.0 g of TA1 (3,3',4,4'-biphenyltetracarboxylic dianhydride) with stirring. 9.1 g of AC1 (isopropanol) was then added and stirred at room temperature for 30 minutes. The mixture was heated to 100 °C and stirred for 3 hours. After the oil bath was removed and the mixture was returned to room temperature, 78.0 g of DA1 (PRIAMINE 1075) as a diamine and 1.5 g of MA1 (m-aminophenol) as a monoamine compound were added with stirring. The mixture was then heated to 100 °C and stirred for 3 hours. The oil bath was then removed and the mixture was returned to room temperature, yielding a varnish-like polyimide precursor. The mixture was then heated at 170 °C for 10 hours while removing the distilled water from the system using a Dean-Stark trap. The mixture was then imidized to obtain polyimide resin (A1). The Mw, Tg and functionalization of the obtained polyimide resin are shown in Table 1.

[0114] [Synthesis Examples 2 to 18, Comparative Synthesis Examples 1 to 3] Polyimide resins (A2) to (A18), (A'1) to (A'3) Polyimide resins (A2) to (A18) and (A'1) to (A'3) were obtained in the same manner as in Synthesis Example 1, except that the monomers shown in Tables 1 and 2 were used.

[0115] [Comparative Synthesis Example 4] Polyimide resin (A'4) A 1 L separable flask equipped with an oil bath and a stirrer was charged with nitrogen gas. 100 g of cyclohexanone was added, followed by 44.0 g of TA1 (3,3',4,4'-biphenyltetracarboxylic dianhydride) with stirring. Subsequently, 78.0 g of DA1 (PRIAMINE 1075) as a diamine and 1.5 g of MA1 (m-aminophenol) as a monoamine compound were added with stirring, and the mixture was stirred at room temperature for 30 minutes. The mixture was heated to 100 °C and stirred for 3 hours. The oil bath was then removed and the mixture was returned to room temperature to obtain a varnish-like polyimide precursor. The mixture was then heated at 170 °C for 10 hours while removing the distilled water using a Dean-Stark trap. The mixture was then imidized to obtain polyimide resin (A'4). The Mw, Tg, and functionalization of the resulting polyimide resin are shown in Table 2.

[0116] The abbreviations in Tables 1 and 2 are listed below. Tetracarboxylic acid dianhydride TA1: 3,3',4,4'-biphenyltetracarboxylic dianhydride / tetracarboxylic dianhydride without aliphatic groups TA2: 1,2,3,4-butanetetracarboxylic dianhydride / tetracarboxylic dianhydride with a chain hydrocarbon structure TA3: 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride / tetracarboxylic acid dianhydride with alicyclic hydrocarbon structure TA4: 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride / tetracarboxylic acid dianhydride with alicyclic hydrocarbon structure Alcohol compounds AC1: Isopropanol AC2: t-butanol AC3: Ethanol Diamine (a2) DA1: Priamine 1075 / Dimer Diamine DA2: 4,4'-(hexafluoroisopropylidene)bis(2-aminophenol) DA3: 1,12-dodecanediamine Monoamines MA1: m-aminophenol MA2: Cysteamine MA3: Norbornenemethylamine MA4: 4-hydroxyphenethylamine (tyramine)

[0117] Tables 1 and 2 show the amount (parts by mass) of the polyimide resin in each synthesis example, the Mw of the resulting polyimide resin, and the content (mol %) of dimer diamine relative to 100 mol % of diamine.

[0118] [Table 1]

[0119] [Table 2]

[0120] Details of the materials used in the examples and comparative examples are shown below. (Curable compound (B)) (B)-1: Epoxy compound, Denacol EX-614B (manufactured by Nagase ChemteX Corporation, sorbitol polyglycidyl ether) (B)-2: Cyanate ester compound, BAD (manufactured by Mitsubishi Gas Chemical Company, Inc., bisphenol A-type cyanate ester) (B)-3: Isocyanate group-containing compound, Duranate TKA-100 (manufactured by Asahi Kasei Corporation, isocyanurate-type isocyanate compound) (B)-4: Metal chelate compound, Orgatix ZC-150 (manufactured by Matsumoto Fine Chemical Co., Ltd., organic zirconia compound) (B)-5: Carbodiimide group-containing compound, Carbodilite V-05 (manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide group-containing compound) (B)-6: Maleimide group-containing compound: BMI-3000 (manufactured by Daiwa Chemical Industry Co., Ltd., bisphenol A-diphenyl ether bismaleimide) (B)-7: Hydrazine compound, N-12 (dodecanedioic acid dihydrazide) (B)-8: Allyl group-containing compound, Taik (manufactured by Shinryo Corporation, triallyl isocyanurate) (B)-9: vinyl group-containing compound, OPE-2St 1200 (manufactured by Mitsubishi Gas Chemical Company, Inc., vinylbenzyl-modified polyphenylene ether) (B)-10: (meth)acryloyl group-containing compound, Noryl SA9000 (manufactured by SABIC, methacryloyl group-containing polyphenylene ether) (Curing accelerator (C)) (C)-1: Radical initiator, Parmicle D (manufactured by NOF Corporation, dicumyl peroxide) (Ultraviolet absorber (D)) (D)-1: Tinuvin 326 (BASF Japan, benzotriazole-containing compound) (Filler (E)) (E)-1: SC2050-MB (Admatechs, silica) (E)-2: SP-2 (Denka, boron nitride) (E)-3: Exolit OP935 (Clariant, aluminum phosphinate) (E)-4: KT-300 (Kitamura Co., Ltd., fluorine-based filler) (E)-5: E101-S (Sumitomo Chemical Co., Ltd., liquid crystal polymer)

[0121] [Example 1] <<Production of coating liquid>> A container was charged with 100 parts of the polyimide resin (A1) of Synthesis Example 1, 5 parts of the curable compound ((B)-1), 5 parts of the ultraviolet absorber (D)-1, and 20 parts of the filler (E)-1 in terms of solid content, and a mixed solvent (toluene:MEK=9:1 (mass ratio)) was added so that the nonvolatile content concentration was 30%, and the mixture was stirred for 10 minutes with a disper to obtain a coating solution.

[0122] <<Adhesive sheet manufacturing>> The obtained coating solution was uniformly applied onto a 50-μm thick double-release film (a polyethylene terephthalate (PET) film coated with a double-release agent) using a doctor blade so that the thickness after drying would be 25 μm, and then dried at 100°C for 2 minutes. Thereafter, it was cooled to room temperature to obtain an adhesive sheet with a single-sided release film. Next, the adhesive sheet surface of the obtained adhesive resin sheet with a single-sided release film was overlaid on a 50-μm thick light-release film (a polyethylene terephthalate (PET) film coated with a light-release agent) to obtain an adhesive sheet with a double-sided release film composed of a double-release film / adhesive sheet / light-release film. The manufactured adhesive sheet was evaluated as described below. The results are shown in Table 3.

[0123] [Examples 2 to 45, Comparative Examples 1 to 4] Coating solutions according to Examples 2 to 45 and Comparative Examples 1 to 4 were prepared in the same manner as in Example 1 except that the compounding components and compounding amounts described in Tables 2 to 4 were changed, and adhesive sheets with double-sided release films were obtained. The evaluation results of each are also shown in Tables 3 to 6.

[0124] <Laminating property with LCP substrate> (Preparation of evaluation sample α) The light-release film was peeled off from the adhesive sheet with a double-sided release film, and the exposed adhesive sheet surface was adhered to the LCP side of a single-sided copper-clad laminate (manufactured by Kuraray Co., Ltd., Vectra (registered trademark) FCCL Fxx-05012) formed by laminating a 50-μm thick LCP film and a 12-μm thick copper foil using a vacuum laminator (a small pressure type vacuum laminator V-130 manufactured by Nichco Materials Co., Ltd.). The vacuum lamination conditions were a heating temperature of 90°C, a vacuum time of 60 seconds, a vacuum reaching pressure of 2 hPa, a pressure of 0.4 MPa, and a pressurization time of 60 seconds. Next, the double-release film was peeled off, and the LCP side of the second single-sided copper-clad laminate was adhered to the exposed adhesive sheet surface in the same manner using a vacuum laminator to prepare an evaluation sample α having a laminated structure of copper foil / LCP film / adhesive sheet / LCP film / copper foil. (Measurement) A test piece 100 mm wide and 100 mm long was cut out from the evaluation sample α and stored in an atmosphere of 23°C and 50% relative humidity for 24 hours or more. Then, a 90° peel test was performed in an atmosphere of 23°C and 50% relative humidity at a pulling rate of 50 mm / min to measure the adhesive strength (N / cm). (Evaluation criteria) A: 2N / cm or more. Very good. B: 1N / cm or more, less than 2N / cm. Good. C: 0.5 N / cm or more and less than 1 N / cm. No practical problems. D: Less than 0.5 N / cm. Not practical.

[0125] <Plating solution resistance of cured product> The plating solution resistance of the cured product was evaluated based on the appearance after testing each test piece under the test conditions I and II below. [I. Acid Plating Test] The adhesive sheet with double-sided release film was cut to a size of 65 mm x 65 mm, and the light-release film was peeled off. The exposed adhesive sheet surface was then laminated at 90°C with the copper surface of a two-layer CCL [ESPANEX MC18-25-00FRM] manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., followed by a 60-minute pressure bonding treatment at 180°C and 2.0 MPa. Finally, the heavy-release film was peeled off to prepare a test specimen for evaluation. The light-release film was peeled off from the adhesive sheet with double-sided release film, and the exposed adhesive sheet surface was subjected to an electroless nickel treatment according to the procedures and conditions a to g below. The appearance of the treated test specimen for evaluation was visually observed to check for any abnormalities, such as swelling or peeling of the adhesive layer after curing. If no abnormalities were found, the electroless nickel treatment steps a to g were repeated twice more. a. Acidic degreasing step: The sample was immersed in ICP Clean S-135K (manufactured by Okuno Chemical Industries Co., Ltd.) at 40°C for 4 minutes. b. Soft etching step: Immersed in sodium persulfate at 30°C for 1 minute. c. Desmutting step: Immersed in sulfuric acid at 25°C for 1 minute. d. Pre-dip step: The sample was immersed in hydrochloric acid at 25°C for 30 seconds. e. Activation step: The sample was immersed in an ICP Accela (manufactured by Okuno Pharmaceutical Industries Co., Ltd.) at 30°C for 1 minute. f. Post-dipping step: Immersed in sulfuric acid at 25°C for 1 minute. g. Electroless nickel plating step: The substrate was immersed in IP Nicoron FPF (manufactured by Okuno Chemical Industries Co., Ltd.) at 85°C for 20 minutes. [II. Alkaline Plating Test] Test pieces for evaluation were prepared in the same manner as in the acid plating test, and these test pieces were subjected to electroless nickel treatment according to the procedures and conditions s to w described below. The appearance of the treated test pieces for evaluation was visually inspected to check for abnormalities such as swelling or peeling of the adhesive layer after curing. Those without abnormalities were subjected to the electroless nickel treatment steps s to w two more times. s. Alkaline degreasing step: The substrate was immersed in an alkaline degreasing agent (50 g / L aqueous solution of Ace Clean A-220 (trade name) manufactured by Okuno Chemical Industries Co., Ltd.) at 50°C for 5 minutes. t. Etching treatment step: The substrate was immersed in an aqueous solution containing 400 g / L of chromic anhydride and 400 g / L of 98% sulfuric acid at 67° C. for 10 minutes. u. Activation step: The sample was immersed in an aqueous solution containing 20 mL / L of 98% sulfuric acid at 25°C for 2 minutes. v. Catalytic activation: The sample was immersed in a catalyst activation solution (aqueous solution containing 10 mL / L of TSP Activator Concentrate (trade name) manufactured by Okuno Chemical Industries Co., Ltd.) at 25° C. for 2 minutes. w. Electroless nickel plating process: The workpiece was immersed in an ammonia-alkali type autocatalytic electroless nickel plating solution (a pH 9 aqueous solution containing 160 mL / L of Chemical Nickel A (trade name) and 160 mL / L of Chemical Nickel B (trade name) manufactured by Okuno Chemical Industries Co., Ltd.) at 40°C for 5 minutes. (Evaluation criteria) A: For both test pieces I and II, there was no visible defect even after the third immersion. Very good. B: For both test pieces I and II, there was no appearance defect until the second immersion, but after the third immersion, at least one of the test pieces showed appearance defect. Good. C: For both test pieces I and II, there was no visual defect until the first immersion, but after the second immersion, visual defects occurred in at least one of the test pieces. This is not a problem for practical use. D: Appearance defects occurred in at least one of the test pieces I and II after the first immersion. Unsuitable for practical use.

[0126] <Insulation reliability after heat cycle testing of cured product> The evaluation method will be explained with reference to Figures 1 to 4. A laminate of 12 μm thick copper foil and 25 μm thick polyimide film was etched, and a cathode electrode comb-shaped signal wiring 2 having cathode electrode connection points 2' and an anode electrode comb-shaped signal wiring 3 having anode electrode connection points 3' were formed on the polyimide film 1 (see Figure 1). The line / space was 0.05 mm / 0.05 mm. Next, the light-release film of the adhesive sheet with double-sided release film was peeled off and the adhesive sheet surface was attached to the surface on which the cathode electrode comb-shaped signal wiring 2 and the anode electrode comb-shaped signal wiring 3 were formed. At this time, the vicinity of the cathode electrode connection point 2' and the vicinity of the anode electrode connection point 3' were exposed. The sheets were then bonded using a vacuum laminator. The heavy-release film was then peeled off to expose the adhesive sheet 4 (see Figure 2). A single-sided copper-clad laminate (MC18-25-00FRM) 5, which had a two-layer structure consisting of an insulating layer 5b and a copper layer 5a, was then bonded to the adhesive sheet 4 using a vacuum laminator so that the insulating layer 5b contacted the adhesive sheet 4. The laminate was then thermally cured in a heat press at 180°C for 1 hour at 2 MPa to form a cured layer 4' of the adhesive sheet 4, yielding a laminate γ for evaluation (see Figures 3 and 4).

[0127] Next, the evaluation laminate γ was subjected to a heat cycle treatment: the evaluation laminate γ was placed in a thermal shock chamber ("TSE-11-A", manufactured by Espec Corporation) and subjected to 200 cycles of alternating high-temperature exposure at 200°C for 30 minutes and low-temperature exposure at -50°C for 15 minutes.

[0128] The removed evaluation laminate γ was then placed in an atmosphere of 85°C and 85% RH (relative humidity), with an anode electrode connected to anode electrode connection point 3' and a cathode electrode connected to cathode electrode connection point 2', and a voltage of 50 V was applied for 1000 hours. The change in resistance was then continuously measured until 1000 hours had passed. "Leak touch" refers to a momentary drop in resistance and current flow caused by insulation breakdown due to a short circuit. If there is no leak touch, there is no deterioration in insulation. The evaluation criteria are as follows. A: Resistance after 1000 hours is 1 x 10 10 Over Ω and no leak touch. Extremely good. B: Resistance after 1000 hours is 1 x 10 8 Ω or more, 1×10 10 Less than Ω and no leak touch. Good. C: Not applicable to A or B, resistance value after 1000 hours is 1 x 10 7 Ω or more and leak touch less than one time. No practical problems. D: Does not fall into any of A to C. Not practical.

[0129] <Laser processability of the cured layer> A method for evaluating the laser processability of the cured layer of an adhesive sheet will be described with reference to Figure 5. The light release film was peeled off from an adhesive sheet with double-sided release film, and the four exposed surfaces of the adhesive sheet were bonded to the copper foil 11 on one side of a double-sided copper-clad laminate 10, which consisted of a 50 μm polyimide film 12 with 12 μm copper foil 11 laminated on both sides. Next, the heavy release film was peeled off, and the polyimide film 22 side of a single-sided copper-clad laminate 20, which consisted of a 50 μm polyimide film 22 and a 12 μm copper foil 21 laminated on both sides, was similarly bonded to the four exposed surfaces of the adhesive sheet using a vacuum laminator. The laminate was then thermally cured in a heat press at 180°C for 1 hour at 2 MPa, yielding an evaluation sample δ having a laminate structure of copper foil 11 / polyimide film 12 / copper foil 11 / cured layer 4' of adhesive sheet / polyimide film 22 / copper foil 21.

[0130] Evaluation sample δ was irradiated with a UV-YAG laser (Model 5330, manufactured by ESI) from the copper foil 21 side of single-sided copper-clad laminate 20, and a blind via with a diameter of 150 μm was drilled up to the boundary between the cured layer 4' of the adhesive sheet and the double-sided copper-clad laminate 10 (see Figure 5). Next, the cross section of the blind via portion 30 was observed with a laser microscope (Keyence VK-X100) at a magnification of approximately 20 to 500 times, and the maximum length of side etching 31 (horizontal etching exceeding the designed opening diameter) occurring in the cured layer 4' of the thermosetting adhesive sheet was measured. The evaluation criteria were as follows: A: 5 μm or less. Very good. B: Over 5 μm and 7 μm or less. Good. C: More than 7 μm and 10 μm or less. No practical problems. D: Over 10 μm. Not practical.

[0131] [Table 3]

[0132] [Table 4]

[0133] [Table 5]

[0134] [Table 6]

[0135] Compositions using terminal polyimide resins (A) having a structure derived from tetracarboxylic acid half esters (a1), which are reaction products of tetracarboxylic dianhydrides and alcohol compounds, and diamines (a2), and having monoamine-modified structures at the molecular chain terminals, were confirmed to have excellent insulation reliability after heat cycle tests and excellent lamination properties to LCP substrates, as shown in Examples 1 to 45. Furthermore, it was confirmed that the cured products had excellent plating solution resistance (alkali resistance and acid resistance). [Explanation of symbols]

[0136] 1 Polyimide film 2. Comb-shaped signal wiring for cathode electrode 2' Cathode electrode connection point 3. Comb-shaped signal wiring for anode electrode 3' Anode electrode connection point 4 adhesive sheets 4' hardened layer 5 Single-sided copper-clad laminate 5a copper layer 5b Insulating layer 10 Double-sided copper-clad laminate 11 Copper foil 12 Polyimide film 20 Single-sided copper-clad laminate 21 Copper foil 22 Polyimide film 30 Blind via section 31 Side Etching

Claims

1. A curable resin composition containing a terminal-modified polyimide resin (A) and a curable compound (B), the terminal-modified polyimide resin (A) has a structure derived from a tetracarboxylic acid half ester (a1) which is a reaction product of a tetracarboxylic acid dianhydride and an alcohol compound, and a diamine (a2), and has a monoamine-modified structure at a molecular chain terminal; A curable resin composition, characterized in that 40 mol % or more of the diamine (a2) is a dimer diamine.

2. 2. The curable resin composition according to claim 1, wherein the curable compound (B) comprises at least one selected from the group consisting of an epoxy compound, a cyanate ester compound, a maleimide compound, a vinyl group-containing compound (excluding an allyl group-containing compound and a (meth)acryloyl group-containing compound), an allyl group-containing compound, and a (meth)acryloyl group-containing compound.

3. The curable resin composition according to claim 1, wherein the terminal-modified polyimide resin (A) accounts for 5 to 99 mass% of a total of 100 mass% of the terminal-modified polyimide resin (A) and the curable compound (B).

4. 2. The curable resin composition according to claim 1, further comprising a filler.

5. 2. The curable resin composition according to claim 1, wherein the terminal-modified polyimide resin (A) has a weight average molecular weight of 10,000 to 100,000.

6. An adhesive sheet comprising a substrate and a resin composition layer formed from the curable resin composition according to any one of claims 1 to 5.

7. A prepreg comprising a substrate impregnated with the curable resin composition according to any one of claims 1 to 5.

8. A cured product obtained from the curable resin composition according to any one of claims 1 to 5.

9. A substrate comprising the cured product according to claim 8.

10. An electronic device comprising the substrate with the cured product according to claim 9.

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