Maleimide resin, resin composition, cured product, sheet, layered product, and printed wiring board

Abstract

This maleimide resin is obtained by reacting a tetracarboxylic acid dianhydride (a1), a diamine (a2), a triamine (a3) and maleic anhydride (a4). The tetracarboxylic acid dianhydride (a1) includes a tetracarboxylic acid dianhydride having an aromatic ring. The diamine (a2) includes a dimer diamine and a second diamine other than a dimer diamine. The second diamine and / or the triamine includes an amine having an aromatic ring.

Description

Maleimide resin, resin composition, cured product, sheet, laminate, and printed wiring board

[0001] The present disclosure relates to a maleimide resin, a resin composition, a cured product, a sheet, a laminate, and a printed wiring board.

[0002] Printed wiring boards and multilayer wiring boards using them are used in products such as mobile communication devices such as mobile phones and smartphones, their base station equipment, network-related electronic devices such as servers and routers, and large computers.

[0003] In recent years, these products have used high-frequency electrical signals to transmit and process large amounts of information at high speed. However, high-frequency signals are highly susceptible to attenuation, and therefore, in order to reduce transmission loss, insulating materials with excellent dielectric properties are required as insulating materials used in the above-mentioned printed wiring boards, multilayer wiring boards, and the like.

[0004] Epoxy resin compositions disclosed in Patent Documents 1 to 3 are known as the insulating material. Patent Document 1 discloses that an epoxy resin composition containing an epoxy resin, an active ester compound, and a triazine-containing cresol novolac resin is effective in reducing dielectric loss tangent. Patent Documents 2 and 3 disclose that a resin composition containing an epoxy resin and an active ester compound as essential components can form a cured product with a low dielectric loss tangent and is useful as an insulating material. However, it has been found that these epoxy resin compositions are unsatisfactory for high-frequency band applications.

[0005] On the other hand, Patent Document 4 reports that a resin film made of a resin composition containing a bismaleimide resin having a long-chain alkyl group as a non-epoxy material and a curing agent has excellent dielectric properties (low relative dielectric constant and low dielectric loss tangent). However, a problem with bismaleimide resins made only of long-chain alkyldiamines is that they have a low glass transition temperature (Tg).

[0006] JP 2011-132507 A JP 2015-101626 A JP 2017-210527 A WO 2016 / 114287

[0007] Insulating materials used in printed wiring boards, multilayer wiring boards, rewiring layers of semiconductor packages, and the like are required to form cured products with a high Tg. Therefore, an object of the present disclosure is to provide a novel maleimide resin capable of forming a cured product with a high Tg while sufficiently maintaining a low dielectric constant and a low dielectric loss tangent. Another object of the present disclosure is to provide a resin composition, a cured product, a sheet, a laminate, and a printed wiring board using the maleimide resin.

[0008] The present disclosure provides the following maleimide resin, resin composition, cured product, sheet, laminate, and printed wiring board: [1] A maleimide resin obtained by reacting a tetracarboxylic dianhydride (a1), a diamine (a2), a triamine (a3), and maleic anhydride (a4), wherein the tetracarboxylic dianhydride (a1) contains a tetracarboxylic dianhydride having an aromatic ring, the diamine (a2) contains a dimer diamine and a second diamine other than the dimer diamine, and at least one of the second diamine and the triamine contains an amine having an aromatic ring. [2] The maleimide resin according to [1] above, wherein the tetracarboxylic dianhydride having an aromatic ring contains at least one of pyromellitic anhydride, 4,4'-oxydiphthalic anhydride, 3,4'-oxydiphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, and 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride. [3] The maleimide resin according to [1] or [2] above, wherein the amine having an aromatic ring is a diamine having an aromatic ring, and the diamine having an aromatic ring contains at least one of 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2,2'-diethylbiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-diethylbiphenyl, 4,4'-diamino-3,3',5,5'-tetramethylbiphenyl, 4,4'-diamino-3,3',5,5'-tetraethylbiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diamino-2,2'-dimethoxybiphenyl, and 4,4'-diamino-3,3'-dimethoxybiphenyl. [4] The maleimide resin according to any one of [1] to [3] above, wherein the dimer diamine contains at least one of a compound represented by the following general formula (1) and a compound represented by the following general formula (2): [In formulas (1) and (2), m, n, p, and q each represent an integer of 1 or greater selected so that m+n=6 to 17 and p+q=8 to 19, and the bond indicated by a dashed line represents a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond indicated by a dashed line is a carbon-carbon double bond, formulas (1) and (2) have a structure in which the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond is subtracted by one from the number indicated in formulas (1) and (2)].] [5] The maleimide resin according to any one of [1] to [4] above, having a weight-average molecular weight of 3,000 to 100,000. [6] A resin composition comprising the maleimide resin according to any one of [1] to [5] above. [7] The resin composition according to [6] above, further comprising a polymerization initiator. [8] A cured product of the resin composition according to [6] above. [9] A sheet comprising the resin composition according to [6] above and a substrate.

[10] The sheet according to [9] above, wherein the substrate is an organic substrate.

[11] The sheet according to [9] above, wherein the substrate is an inorganic substrate.

[12] A laminate obtained by thermocompression bonding a substrate to the adhesive surface of the sheet according to [9] above.

[13] A printed wiring board obtained by using the sheet according to [9] above.

[14] A printed wiring board obtained by using the laminate according to

[12] above.

[0009] According to the present disclosure, it is possible to provide a maleimide resin capable of forming a cured product having a high Tg while sufficiently maintaining a low dielectric constant and a low dielectric loss tangent. The present disclosure also provides a resin composition, a cured product, a sheet, a laminate, and a printed wiring board using the maleimide resin.

[0010] The maleimide resin of the present disclosure and a resin composition (adhesive composition) using the same can reduce both the dielectric constant and the dielectric loss tangent (hereinafter, both may be collectively referred to as "dielectric properties"), and are excellent in low dielectric properties, particularly in the high frequency band. Furthermore, the cured product (adhesive layer) obtained from the resin composition not only has a high elastic modulus and Tg, but also excellent toughness. Therefore, the resin composition is useful not only as an adhesive used in the production of printed circuit boards (build-up boards, flexible printed wiring boards, etc.) and copper-clad boards for printed wiring boards, but also as an insulating film such as a rewiring layer, a semiconductor interlayer material, a coating agent, a resist ink, a conductive paste, etc.

[0011] Preferred embodiments of the present disclosure will be described in detail below. However, the present disclosure is not limited to the following embodiments and can be implemented in various modifications within the scope of the present disclosure.

[0012] In this specification, numerical ranges indicated using "to" indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. "A or B" may include either A or B, or may include both. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. In this specification, "solid content" refers to the non-volatile content of the resin composition excluding volatile substances (water, solvent, etc.), and also includes components that are liquid, syrup-like, or waxy at room temperature (around 25°C).

[0013] [Maleimide Resin and Resin Composition] The maleimide resin of this embodiment is a maleimide resin obtained by reacting a tetracarboxylic dianhydride (a1) (hereinafter also referred to as "component (a1)"), a diamine (a2) (hereinafter also referred to as "component (a2)"), a triamine (a3) ​​(hereinafter also referred to as "component (a3)"), and maleic anhydride (a4) (hereinafter also referred to as "component (a4)"). Here, the component (a1) includes a tetracarboxylic dianhydride having an aromatic ring, and the component (a2) includes a dimer diamine and a second diamine other than the dimer diamine, and at least one of the second diamine and the triamine includes an amine having an aromatic ring. The amine having an aromatic ring is a diamine having an aromatic ring or a triamine having an aromatic ring. The aromatic ring may have a lower alkyl (e.g., methyl, ethyl, propyl, etc.) as a substituent.

[0014] The resin composition of this embodiment contains the maleimide resin (A) (hereinafter also referred to as "component (A)"). The resin composition of this embodiment may further contain a polymerization initiator (B) (hereinafter also referred to as "component (B)"). The resin composition of this embodiment may further contain an organic solvent (C) (hereinafter also referred to as "component (C)").

[0015] (Component (A): Maleimide Resin) Component (A) can be obtained by reacting components (a1), (a2), (a3), and (a4). Component (A) is a polyfunctional maleimide compound having two or more maleimide groups, and may have multiple maleimide groups in the molecule.

[0016] The tetracarboxylic acid dianhydride of the component (a1) includes a tetracarboxylic acid dianhydride having an aromatic ring. Examples of the tetracarboxylic acid dianhydride having an aromatic ring include pyromellitic anhydride, 4,4'-oxydiphthalic anhydride, 3,4'-oxydiphthalic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,3',3,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 4,4'-(4, aromatic tetracarboxylic acid dianhydrides not having a fluorene skeleton, such as 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, and 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-C]furan-1,3-dione.

[0017] From the viewpoint of achieving a high Tg of the cured product, the component (a1) preferably contains, as a tetracarboxylic dianhydride having an aromatic ring, at least one of pyromellitic anhydride, 4,4'-oxydiphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, and 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride.

[0018] From the viewpoints of the solubility of the maleimide resin and a high Tg of the cured product, it is preferable to use a tetracarboxylic acid dianhydride having a fluorene skeleton and an aromatic tetracarboxylic acid dianhydride not having a fluorene skeleton in combination as the tetracarboxylic acid dianhydride having an aromatic ring. Component (a1) may include, for example, 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride and at least one of pyromellitic anhydride, 4,4'-oxydiphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, and 2,3',3,4'-biphenyltetracarboxylic acid dianhydride.

[0019] The component (a1) may further contain a tetracarboxylic acid dianhydride that does not have an aromatic ring. Examples of the tetracarboxylic acid dianhydride that does not have an aromatic ring include 1,2,3,4-butanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, and bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)1,4-phenylene. , 4,4'-(ethyne-1,2-diyl)diphthalic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride, and 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic-5,5',6,6'-dianhydride.

[0020] The component (a2) contains a dimer diamine (first diamine) and a second diamine other than the dimer diamine.

[0021] Dimer diamine is a compound derived from dimer acid, which is a dimer of unsaturated fatty acids such as oleic acid, as described in, for example, JP-A-9-12712. By using dimer diamine as component (a2), the dielectric properties of the cured product can be reduced. In this embodiment, any known dimer diamine can be used without particular limitations. The dimer diamine preferably includes, for example, at least one of a compound represented by the following general formula (1) and a compound represented by the following general formula (2):

[0022]

[0023] In formulas (1) and (2), m, n, p, and q each represent an integer of 1 or greater selected so that m+n=6 to 17 and p+q=8 to 19, and the bond shown by a dashed line represents a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond shown by a dashed line is a carbon-carbon double bond, formulas (1) and (2) have a structure in which the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond is reduced by one from the number shown in formulas (1) and (2).

[0024] The dimer diamine may be one represented by the above general formula (2), particularly a compound represented by the following formula (3), from the viewpoints of solubility in organic solvents, heat resistance, heat-resistant adhesion, low viscosity, etc.

[0025] Commercially available dimer diamines include, for example, PRIAMINE 1075 and PRIAMINE 1074 (both manufactured by Croda Japan), etc. These may be used alone or in combination of two or more.

[0026] The second diamine is a diamine that does not fall under the category of the above-mentioned dimer diamine. The second diamine may include a diamine having an aromatic ring as the amine having an aromatic ring.

[0027] Examples of diamines having an aromatic ring include 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2,2'-diethylbiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-diethylbiphenyl, 4,4'-diamino-3,3',5,5'-tetramethylbiphenyl, 4,4'-diamino-3,3',5,5'-tetraethylbiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diamino-2, Diamines having a biphenyl skeleton such as 2'-dimethoxybiphenyl and 4,4'-diamino-3,3'-dimethoxybiphenyl; diamines having a fluorene skeleton such as 2,7-diaminofluorene, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis[3-fluoro-4-aminophenyl]fluorene and 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene; phenylenediamines such as paraphenylenediamine, orthophenylenediamine and metaphenylenediamine; and 4,4-methylenediamine. Aniline, 4,4'-ethylenedianiline, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-(hexafluoroisopropylidene)dianiline, 1,1-bis(4-aminophenyl)cyclohexane, 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(2-ethyl-6-methylaniline), 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis Examples of bisaniline derivatives include [4-(4-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, bis[4-(3-aminophenoxy)phenyl]sulfone, and bis[4-(4-aminophenoxy)phenyl]sulfone. These can be used alone or in combination of two or more.

[0028] From the viewpoint of increasing the Tg of the cured product, the diamine having an aromatic ring may contain at least one diamine having a biphenyl skeleton selected from 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2,2'-diethylbiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-diethylbiphenyl, 4,4'-diamino-3,3',5,5'-tetramethylbiphenyl, 4,4'-diamino-3,3',5,5'-tetraethylbiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diamino-2,2'-dimethoxybiphenyl, and 4,4'-diamino-3,3'-dimethoxybiphenyl.

[0029] The content of the diamine having an aromatic ring, based on the total amount of components (a2) and (a3), may be 20 mol% or more, 25 mol% or more, 30 mol% or more, or 35 mol% or more from the viewpoint of increasing the Tg of the cured product, and may be 60 mol% or less, 55 mol% or less, 50 mol% or less, or 45 mol% or less from the viewpoint of decreasing the dielectric properties of the cured product.

[0030] The second diamine may include a diamine having no aromatic ring. Examples of the diamine having no aromatic ring include 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane, 1,16-diaminohexadecane, 2-methyl-1,5-pentamethylenediamine, 2,2,4-trimethylhexane-1,6-diamine, norbornanediamine, 1,3-bis(aminomethyl)cyclohexane, 1, 4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.02,6]decane, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, isophoronediamine, 4,4′-methylenebis(cyclohexylamine), and 4,4′-methylenebis(2-methylcyclohexylamine).

[0031] Examples of triamines of component (a3) ​​include aliphatic triamines such as tris(2-aminomethyl)amine, tris(2-aminoethyl)amine, tris(2-aminopropyl)amine, 2-(aminomethyl)-2-methyl-1,3-propanediamine, and trimer triamine; triamines having a heterocyclic ring such as 1,3,5-triazine-2,4,6-triamine and 2,4,6-triaminopyrimidine; and triamines having an aromatic ring such as 3,4,4'-triaminodiphenyl ether, 1,2,4-triaminobenzene, 1,3,5-triaminobenzene, 1,2,3-triaminobenzene, 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-tris(4-aminophenoxy)benzene, and tris(4-aminophenyl)methane. These can be used alone or in combination of two or more. Of these, aliphatic triamines are preferred from the viewpoint of the solubility of the synthesized component (A) in organic solvents, and tris(2-aminomethyl)amine and tris(2-aminoethyl)amine, which have a small number of carbon atoms, are more preferred from the viewpoint of achieving a high Tg.

[0032] The content of the component (a3), based on the total amount of the components (a2) and (a3), may be 1 mol % or more, 4 mol % or more, 6 mol % or more, or 8 mol % or more from the viewpoints of the haze (turbidity) of the maleimide resin and the elastic modulus and Tg of the cured product, and may be 30 mol % or less, 25 mol % or less, 20 mol % or less, or 15 mol % or less from the viewpoints of the solubility and haze of the maleimide resin.

[0033] By using dimer diamine as the diamine, a cured product with lower dielectric properties can be formed. On the other hand, if only dimer diamine is used as the diamine, the Tg of the cured product will be lowered and the coefficient of linear expansion (CTE) will be higher. On the other hand, by using a triamine, the solubility of the maleimide resin will be improved and the residual film rate will be increased during pattern formation by photolithography, making it easier to form fine vias. By using an amine having an aromatic ring, the Tg of the cured product will be easier to increase. By using a dimer diamine, a second diamine, and a triamine, the solubility of the maleimide resin will be improved and the Tg of the cured product will be improved while maintaining the dielectric properties.

[0034] Component (A) can be produced by various known methods. For example, components (a1), (a2), and (a3) ​​are first subjected to a polyaddition reaction at a temperature of about 60 to 120°C, preferably 70 to 90°C, for typically about 0.1 to 2 hours, preferably 0.1 to 1.0 hour. The resulting polyaddition product is then subjected to an imidization reaction, i.e., a dehydration ring-closing reaction, at a temperature of about 80 to 250°C, preferably 100 to 200°C, for about 0.5 to 30 hours, preferably 0.5 to 10 hours. The product of the dehydration ring-closing reaction is then subjected to a maleimidization reaction, i.e., a dehydration ring-closing reaction, with component (a4) at a temperature of about 60 to 250°C, preferably 80 to 200°C, for about 0.5 to 30 hours, preferably 0.5 to 10 hours, to obtain the desired component (A).

[0035] In the imidization reaction or maleimidization reaction, various known reaction catalysts, dehydrating agents, and organic solvents described below can be used. Examples of reaction catalysts include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, heterocyclic tertiary amines such as pyridine, picoline, and isoquinoline, and organic acids such as methanesulfonic acid and paratoluenesulfonic acid monohydrate. These can be used alone or in combination of two or more. Examples of dehydrating agents include aliphatic acid anhydrides such as acetic anhydride, and aromatic acid anhydrides such as benzoic anhydride. These can be used alone or in combination of two or more.

[0036] Component (A) can be purified by various known methods to increase its purity. For example, first, component (A) dissolved in an organic solvent and pure water are placed in a separatory funnel. The separatory funnel is then shaken and allowed to stand. Subsequently, the aqueous layer and the organic layer are separated, and only the organic layer is recovered, thereby purifying component (A).

[0037] The component (A) produced by the above method may contain one or more structural units represented by the following general formulas (4) to (6). The range of the number of functional groups (number of maleimide groups) of the component (A) depends on the triamine content, but is expected to be 2 to 6 functional groups per molecule. The component (A) may be a mixture of multiple compounds having different structures or different numbers of functional groups. The component (A) may contain a compound having three or more functional groups per molecule, including one or more structural units represented by the following general formulas (5) to (6).

[0038]

[0039] In general formulas (4) to (6), X each independently represents a tetravalent organic group, Y each independently represents a divalent organic group, and Z each independently represents a trivalent organic group. X, Y, and Z may be an aliphatic group, an organic group having an alicyclic structure, or an aromatic ring, and may contain a heteroatom. Y may be an organic group derived from a dimer diamine, and Z may be an organic group derived from a triamine (a3).

[0040] An example of the structure of component (A) produced by the above method is shown in general formula (7) below.

[0041]

[0042] X, Y, and Z in general formula (7) are synonymous with X, Y, and Z in general formulas (4) to (6). Furthermore, a represents an integer of 0 to 20, b represents an integer of 0 to 30, c represents an integer of 0 to 20, and d represents an integer of 1 to 30. In general formula (7), the positions of the structural unit assigned with the symbol a (structural unit represented by the above general formula (5)), the structural unit assigned with the symbol b (structural unit represented by the above general formula (4)), and the structural unit assigned with the symbol c (structural unit represented by the above general formula (6)) may be interchanged. Component (A) may contain a compound having three or more functional groups per molecule, in which at least one of a and c is an integer of 1 or greater.

[0043] The molecular weight of component (A) can be controlled by the number of moles of component (a1), component (a2), and component (a3), and the smaller the number of moles of component (a1) is compared to the total number of moles of component (a2) and component (a3) ​​combined, the smaller the molecular weight can be. For the purpose of easily achieving the effects of the present disclosure, the number of moles of component (a1) per mole of component (a2) and component (a3), i.e., [number of moles of component (a1)] / [number of moles of component (a2) + number of moles of component (a3)] is usually about 0.30 to 0.98, preferably 0.40 to 0.96, more preferably 0.50 to 0.94, and even more preferably 0.60 to 0.90.

[0044] From the viewpoint of solubility in solvents and heat resistance, the molecular weight of component (A) is preferably a weight average molecular weight (Mw) of 3,000 to 100,000, and may be 3,000 to 80,000, 4,000 to 70,000, 5,000 to 50,000, 6,000 to 40,000, 6,500 to 36,000, 7,000 to 30,000, or 7,000 to 27,000. When component (A) has an Mw of 100,000 or less, solubility in organic solvents is good, and when it is 3,000 or more, the effect of improving heat resistance tends to be sufficiently obtained. From this viewpoint, the lower limit of Mw of component (A) may be 4000 or more, 5000 or more, 6000 or more, 6500 or more, 7000 or more, or 7500 or more, and the upper limit of Mw of component (A) may be 80000 or less, 70000 or less, 60000 or less, 50000 or less, 40000 or less, 36000 or less, 30000 or less, or 27000 or less. Mw can be measured by gel permeation chromatography (GPC) and converted using a calibration curve of standard polystyrene.

[0045] The component (A) can be used alone or in combination of two or more.

[0046] (Component (B): Polymerization Initiator) As the component (B), various known polymerization initiators that can be used in resin compositions can be used without any particular limitation. Specific examples of the component (B) include organic peroxides, imidazole compounds, phosphine compounds, and phosphonium salt compounds. These can be used alone or in combination of two or more. Among these, organic peroxides and imidazole compounds are particularly preferred because they have excellent functionality as polymerization initiators and are also excellent in terms of low dielectric properties.

[0047] Examples of organic peroxides include methyl ethyl ketone peroxide, methylcyclohexanone peroxide, methylacetoacetate peroxide, acetylacetone peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(4,4-di-t-butylperoxy)cyclohexane, t-butylperoxycyclohexyl)propane, 1,1-bis(t-butylperoxy)cyclododecane, n-butyl-4,4-bis(t-butylperoxy)valerate, 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)-2-methylcyclohexane, t-butyl hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, t-hexyl hydroperoxide, dicumyl peroxide, 2,5-dimethyl -2,5-bis(t-butylperoxy)hexane, α,α'-bis(t-butylperoxy)diisopropylbenzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, cinnamic acid peroxide, m-toluoyl peroxide, benzoyl peroxide, diisopropyl Peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di(3-methyl-3-methoxybutyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, α,α'-bis(neodecanoylperoxy)diisopropylbenzene, cumyl peroxyneodecanoate, 1,1,3,3,-Tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy Examples of suitable peroxybenzoates include tert-butylperoxymethylperoxymethyl esters, tert-butyl ... Among these organic peroxides, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, α,α'-bis(t-butylperoxy)diisopropylbenzene, etc. are preferred.

[0048] Examples of the imidazole compound include 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2,4-dimethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-vinyl-2-methylimidazole, 1-propyl-2-methylimidazole, 2-isopropylimidazole, 1-cyanomethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, and 1-cyanoethyl-2-phenylimidazole. Among these, 1-cyanoethyl-2-phenylimidazole and 2-ethyl-4-methylimidazole are preferred because they have high solubility in the resin composition of this embodiment. These can be used alone or in combination of two or more.

[0049] Examples of phosphine compounds include primary phosphines, secondary phosphines, and tertiary phosphines. Primary phosphines include alkyl phosphines such as ethylphosphine and propylphosphine, and phenylphosphine. Secondary phosphines include dialkyl phosphines such as dimethylphosphine and diethylphosphine, and secondary phosphines such as diphenylphosphine, methylphenylphosphine, and ethylphenylphosphine. Tertiary phosphines include trialkyl phosphines such as trimethylphosphine, triethylphosphine, tributylphosphine, and trioctylphosphine, tricyclohexylphosphine, triphenylphosphine, alkyldiphenylphosphines, dialkylphenylphosphines, tribenzylphosphine, tritolylphosphine, tri-p-styrylphosphine, tris(2,6-dimethoxyphenyl)phosphine, tri-4-methylphenylphosphine, tri-4-methoxyphenylphosphine, and tri-2-cyanoethylphosphine. Among these, tertiary phosphines are preferably used. These may be used alone or in combination of two or more.

[0050] Examples of the phosphonium salt compound include tetraphenylphosphonium salts, alkyltriphenylphosphonium salts, compounds having tetraalkylphosphonium, etc., and specific examples include tetraphenylphosphonium thiocyanate, tetraphenylphosphonium tetra-p-methylphenylborate, butyltriphenylphosphonium thiocyanate, tetraphenylphosphonium phthalic acid, tetrabutylphosphonium 1,2-cyclohexyldicarboxylic acid, tetrabutylphosphonium 1,2-cyclohexyldicarboxylic acid, tetrabutylphosphonium lauric acid, etc. These may be used alone or in combination of two or more.

[0051] The content of the (B) component is not particularly limited, but may be 0.1 to 10.0 parts by mass, 0.2 to 5.0 parts by mass, 0.3 to 3.0 parts by mass, 0.3 to 2.0 parts by mass, or 0.3 to 1.0 parts by mass per 100 parts by mass of the (A) component.

[0052] (Component (C): Organic Solvent) The component (C) is not particularly limited as long as it dissolves the component (A). Examples of the component (C) include aromatic hydrocarbon solvents such as benzene, toluene, xylene, mesitylene, and pseudocumene; alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; ether solvents such as anisole; ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclopentanone, cyclohexanone, isophorone, and acetophenone; cellosolves such as methyl cellosolve and ethyl cellosolve; methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate. Examples of suitable solvents include ester-based solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso-butyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether; and amide-based solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone. These solvents can be used alone or in combination of two or more. Among these, aromatic hydrocarbons such as toluene, mesitylene, and pseudocumene, which have high solubility for component (A), are preferably used.

[0053] The amount of component (C) used is not particularly limited, but it is usually sufficient to use it in a range such that the nonvolatile content of the resin composition of this embodiment is about 20 to 65 mass %.

[0054] The resin composition of this embodiment is prepared according to a commonly employed method. Examples of the preparation method include melt mixing, powder mixing, and solution mixing. In addition, in this case, other components than the essential components of this embodiment, such as a mold release agent, a flame retardant, an ion trapping agent, an antioxidant, an adhesion promoter, a stress reducing agent, a colorant, a coupling agent, and an inorganic filler, may be blended within a range that does not impair the effects of the present disclosure. The resin composition of this embodiment may also contain a resin other than the component (A), such as an epoxy resin, an acrylate compound, a vinyl compound, a benzoxazine compound, or a maleimide compound other than the component (A).

[0055] (Mold Release Agent) A mold release agent is added to improve releasability from a mold. As the mold release agent, any of known agents can be used, such as carnauba wax, rice wax, candelilla wax, polyethylene, polyethylene oxide, polypropylene, montanic acid, montan wax which is an ester compound of montanic acid with saturated alcohol, 2-(2-hydroxyethylamino)ethanol, ethylene glycol, glycerin, etc., stearic acid, stearic acid ester, stearic acid amide, etc. These can be used alone or in combination of two or more.

[0056] (Flame retardant) The flame retardant is added to impart flame retardancy, and any known flame retardant can be used, and is not particularly limited. Examples of the flame retardant include phosphazene compounds, silicon compounds, zinc molybdate-supported talc, zinc molybdate-supported zinc oxide, aluminum hydroxide, magnesium hydroxide, and molybdenum oxide. These can be used alone or in combination of two or more.

[0057] (Ion trapping agent) The ion trapping agent is added to capture ionic impurities contained in the liquid resin composition and prevent thermal degradation and moisture absorption degradation. Any known ion trapping agent can be used, and there are no particular limitations. Examples of the ion trapping agent include hydrotalcites, bismuth hydroxide compounds, and rare earth oxides. These can be used alone or in combination of two or more.

[0058] (Inorganic Filler) The inorganic filler can be any known inorganic filler that can be used in a resin composition, without any particular limitation. Examples of inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, boron nitride, silica, graphite powder, and boehmite. Among these, silica is particularly preferred because of its low dielectric loss tangent. The inorganic fillers can be used alone or in combination of two or more.

[0059] The average particle size of the inorganic filler may be 50 nm or more, 100 nm or more, or 200 nm or more, and may be 10 μm or less, 5.0 μm or less, 3.0 μm or less, or 1.0 μm or less. The average particle size of the inorganic filler is preferably 100 nm to 10 μm or 50 nm to 5.0 μm, more preferably 100 nm to 3.0 μm, and even more preferably 200 nm to 1.0 μm. When the average particle size of the inorganic filler is within the above range, the surface roughness of the sheet can be reduced and adhesion to substrates such as polyimide films and copper foils can be improved.

[0060] The average particle size of the inorganic filler is determined by the median diameter (d50) at 50% of the cumulative particle size in the volume cumulative particle size distribution. The average particle size can be measured using a laser diffraction / scattering particle size distribution analyzer.

[0061] The inorganic filler is preferably surface-treated, preferably with a coupling agent, more preferably with a silane coupling agent. By surface-treating the inorganic filler, not only can the dispersibility of the inorganic filler in an organic solvent be improved, but also the surface roughness of the sheet surface can be further reduced, and the adhesion to substrates such as polyimide films and copper foils can be improved.

[0062] Examples of the coupling agent include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include methacrylsilane, acrylic silane, aminosilane, phenylaminosilane, imidazole silane, phenylsilane, vinylsilane, and epoxysilane. These can be used alone or in combination of two or more.

[0063] When the resin composition contains an inorganic filler, the content thereof may be 5 to 75 mass%, 5 to 50 mass%, 5 to 35 mass%, or 10 to 30 mass%, based on the total amount of solids (non-volatile content) of the resin composition (100 mass%). When the content of the inorganic filler is 75 mass% or less, a decrease in adhesiveness tends to be suppressed, and when it is 5 mass% or more, the effect of reducing the dielectric loss tangent and the effect of improving heat resistance tend to be sufficiently obtained.

[0064] [Cured Product] The cured product of this embodiment is obtained by curing the resin composition of this embodiment. Specifically, it can be obtained by heat treating the composition at about 150 to 250°C for about 10 minutes to 3 hours.

[0065] The shape of the cured product of the present embodiment is not particularly limited, but when used for bonding substrates, it can be in the form of a sheet having a thickness of usually about 1 to 200 μm, preferably about 3 to 100 μm, and the thickness can be adjusted appropriately depending on the application.

[0066] [Sheet] The sheet of this embodiment comprises the resin composition of this embodiment and a substrate. The sheet of this embodiment can be obtained, for example, by applying the resin composition of this embodiment to a substrate (sheet substrate) and drying it. Examples of the substrate include organic substrates such as polyimide, polyimide-silica hybrid, polyamide, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate resin (PMMA), polystyrene resin (PSt), polycarbonate resin (PC), acrylonitrile-butadiene-styrene resin (ABS), ethylene terephthalate, phenol, phthalic acid, aromatic polyester resin obtained from hydroxynaphthoic acid or the like and parahydroxybenzoic acid (so-called liquid crystal polymer: "Vextar" manufactured by Kuraray Co., Ltd., etc.). Among these, polyimide film, particularly polyimide-silica hybrid film, is preferred in terms of heat resistance and dimensional stability. Furthermore, inorganic substrates such as glass, iron, aluminum, 42 alloy, copper, and the like, as well as ITO, silicon, and silicon carbide may also be used as the substrate. The thickness of the substrate can be appropriately set depending on the application.

[0067] [Laminate] The laminate of this embodiment can be obtained by thermocompression bonding a substrate to the adhesive surface of the sheet. Examples of the substrate include organic substrates such as polyimide, polyimide-silica hybrid, polyamide, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate resin (PMMA), polystyrene resin (PSt), polycarbonate resin (PC), acrylonitrile-butadiene-styrene resin (ABS), ethylene terephthalate, phenol, phthalic acid, aromatic polyester resin (liquid crystal polymer) obtained from hydroxynaphthoic acid or the like and parahydroxybenzoic acid. The substrate may also be glass, iron, aluminum, 42 alloy, copper, or other metals, or inorganic substrates such as ITO, silicon, or silicon carbide. The thickness of the substrate can be appropriately set depending on the application. The laminate may also be further heat-treated.

[0068] [Printed Circuit Board and Printed Wiring Board] The printed circuit board of this embodiment uses the above-mentioned sheet or the above-mentioned laminate. The printed circuit board of this embodiment can be obtained, for example, by further laminating the adhesive surface of the above-mentioned sheet to the inorganic substrate surface of the above-mentioned laminate. The printed circuit board preferably uses a polyimide film as the organic substrate and a metal foil (particularly copper foil) as the inorganic substrate. Then, the metal surface of such a printed circuit board is soft-etched to form a circuit, and the above-mentioned sheet is further laminated thereon and hot-pressed to obtain a printed wiring board.

[0069] The present disclosure will be specifically described below with reference to examples and comparative examples, but the present disclosure is not limited thereto. In each example, parts and percentages are by mass unless otherwise specified.

[0070] [Synthesis of Maleimide Resin] To synthesize a maleimide resin, the following components (a1) to (a4), an acid catalyst, and a solvent were prepared. (Component (a1)) BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (manufactured by JFE Chemical Corporation, trade name "BPAF") PMDA: pyromellitic dianhydride (manufactured by Daicel Corporation) ODPA: 4,4'-oxydiphthalic anhydride (manufactured by Manac Corporation, trade name "ODPA") s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride (manufactured by JFE Chemical Corporation, trade name "BPDA") a-BPDA: 2,3',3,4'-biphenyltetracarboxylic dianhydride (manufactured by JFE Chemical Corporation, trade name "a-BPDA") BISDA: 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (manufactured by SABIC, trade name "BISDA-1000") (Component (a2)) DDA: dimer diamine (manufactured by Croda Japan Co., Ltd., trade name "PRIAMINE 1075") mTBHG: 4,4'-diamino-2,2'-dimethylbiphenyl (manufactured by Wakayama Seika Kogyo Co., Ltd., trade name "m-TB-HG") NBDA: norbornanediamine (manufactured by Mitsui Fine Chemicals, Inc.) (component (a3)) TAEA: tris(2-aminoethyl)amine (manufactured by Tokyo Chemical Industry Co., Ltd.) TAPOB: 1,3,5-tris(4-aminophenoxy)benzene (manufactured by Seika Corporation) TAPM: tris(4-aminophenyl)methane (manufactured by Tokyo Chemical Industry Co., Ltd.) (component (a4)) Maleic anhydride (manufactured by Fuso Chemical Co., Ltd.) (acid catalyst) Methanesulfonic acid aqueous solution (manufactured by BASF, trade name "Lutropur MSA") (solvent) Pseudocumene (manufactured by Toyo Gosei Co., Ltd., aromatic high-boiling point solvent) Solmix A-11 (manufactured by Japan Alcohol Sales Co., Ltd., alcohol-based solvent) γ-butyrolactone (manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) Toluene (manufactured by Yamaichi Chemical Industry Co., Ltd.)

[0071] Synthesis Example 1 Into a 0.3 L flask equipped with a condenser, a nitrogen inlet tube, a thermocouple, and a stirrer, 16.87 parts by mass of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 10.82 parts by mass of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), 127.03 parts by mass of pseudocumene, 36.27 parts by mass of Solmix A-11, and 29.91 parts by mass of γ-butyrolactone were placed. After addition, the temperature was raised to 80 ° C., and the temperature was maintained for 0.5 hours. 26.33 parts by mass of dimer diamine (DDA) was added dropwise, followed by 0.96 parts by mass of tris(2-aminoethyl)amine (TAEA), and then 8.33 parts by mass of 4,4'-diamino-2,2'-dimethylbiphenyl (mTBHG) was added. After the addition, 2.47 parts by mass of aqueous methanesulfonic acid was added, and the temperature was raised to 160 ° C. After the temperature was raised, 40.00 parts by mass of toluene was added, and a dehydration ring-closing reaction was carried out at 160 ° C. for 3 hours. The water and alcohol in the reaction solution were removed, and an intermediate polyimide resin was obtained. Subsequently, the polyimide resin was cooled to 130 ° C., 7.21 parts by mass of maleic anhydride was added, and the temperature was raised to 160 ° C., and a dehydration ring-closing reaction was carried out at 160 ° C. for 4 hours. The water in the reaction solution was removed, and a maleimide resin was obtained.

[0072] The maleimide resin was placed in a separatory funnel, and 500 parts by mass of pure water was added. The separatory funnel was shaken and allowed to stand. After standing, the aqueous layer and organic layer separated, and only the organic layer was recovered. The recovered organic layer was placed in a 1 L glass vessel equipped with a cooler, a nitrogen inlet tube, a thermocouple, a stirrer, and a vacuum pump, heated to 88 to 93°C, and the water was removed. The vessel was then heated to 100°C and the solvent was partially removed for 0.5 hours under a reduced pressure of 0.1 MPa from atmospheric pressure, yielding a solution of maleimide resin (A-1) of component (A).

[0073] Synthesis Examples 2 to 9 Solutions of maleimide resins (A-2) to (A-9) were obtained in the same manner as in Synthesis Example 1, except that the amounts of each component were changed as shown in Table 1.

[0074] Synthesis Examples 10 to 16 Solutions of maleimide resins (A-10) to (A-16) were obtained in the same manner as in Synthesis Example 1, except that the amounts of each component were changed as shown in Table 2.

[0075] Comparative Synthesis Examples 1 to 4 Solutions of maleimide resins (A-17) to (A-20) were obtained in the same manner as in Synthesis Example 1, except that the amounts of each component were changed as shown in Table 3.

[0076] (Non-volatile content) 0.75 g±0.25 g of each of the solutions of maleimide resins (A-1) to (A-20) was weighed out using a precision balance and placed in a metal Petri dish, and then dried in a hot air dryer at 150°C for 0.5 hours. The non-volatile content (NV) was calculated using the following formula: NV (mass%) = {(W3 - W1) / W2} × 100, where W1 is the mass (g) of the empty metal Petri dish, W2 is the mass (g) of the maleimide resin solution before drying, and W3 is the mass (g) of the metal Petri dish + maleimide resin after drying.

[0077] (Weight-average molecular weight) The weight-average molecular weight (Mw) of the maleimide resin was measured by gel permeation chromatography (GPC). A sample prepared by dissolving maleimide resin in tetrahydrofuran (THF) to a concentration of 3% by mass was injected in an amount of 50 μL into a column (GL-R420 (Hitachi High-Tech Fielding Corporation) x 1, GL-R430 (Hitachi High-Tech Fielding Corporation) x 1, GL-R440 (Hitachi High-Tech Fielding Corporation) x 1) heated to 30 ° C., and measurement was performed using THF as the developing solvent at a flow rate of 1.6 mL / min. The detector used was an L-3350 RI detector (Hitachi, Ltd.), and Mw was calculated from the elution time using a molecular weight / elution time curve created using standard polystyrene (Tosoh Corporation). The maleimide resin (A-17) of Comparative Synthesis Example 2 and the maleimide resin (A-20) of Comparative Synthesis Example 4 were insoluble in THF, and therefore Mw could not be measured.

[0078] (HAZE) The haze (turbidity) of the maleimide resin solution was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name "NDH8000"). The maleimide resin solution was poured into a stone cell with a width of 1.0 cm, a horizontal width of 3.6 cm, and a height of 5.5 cm, and measurement was performed after standard calibration with pure water. Note that the maleimide resin (A-17) of Comparative Synthesis Example 2 and the maleimide resin (A-20) of Comparative Synthesis Example 4 were insoluble in solvents, and therefore the haze could not be measured.

[0079] (Solubility) The solubility of the maleimide resin was evaluated by placing the maleimide resin solution in a 20 mL screw tube and visually checking for the presence of precipitates or turbidity. The solubility was evaluated as "A" when the maleimide resin solution had no precipitates or turbidity, "B" when the maleimide resin solution had turbidity but no precipitates, and "C" when the maleimide resin solution had precipitates.

[0080]

[0081]

[0082]

[0083] [Examples 1 to 16 and Comparative Examples 1 to 4] (Preparation of Resin Compositions) The maleimide resin compositions of the Examples were prepared by blending the components shown below in the compositions shown in Table 4 or Table 5, and the maleimide resin compositions of the Comparative Examples were prepared by blending the components shown below in the compositions shown in Table 6. The blending amount of component (A) shown in Tables 4 to 6 indicates the blending amount (parts by mass) including the solvent. Note that the maleimide resin compositions of Comparative Examples 2 and 4 could not be evaluated because the maleimide resin was insoluble in the solvent.

[0084] Component (A): Maleimide resins (A-1) to (A-20) Component (B): DCP (manufactured by NOF Corporation, trade name "Percumyl D", dicumyl peroxide) Component (C): Pseudocumene (manufactured by Toyo Gosei Co., Ltd., aromatic high-boiling point solvent)

[0085] (Preparation of cured sheet) Using an applicator, the maleimide resin composition was applied onto Cu foil (manufactured by Mitsui Mining & Smelting Co., Ltd., product name "3EC-M2S-VLP") so that the thickness after drying would be 100 μm, and the composition was dried in a dryer at 130°C for 30 minutes. Subsequently, the composition was cured in a nitrogen dryer at 200°C for 1 hour. After curing, the composition was cooled to room temperature, and then the copper foil was removed by etching with an aqueous ammonium persulfate solution, and the composition was dried at 110°C for 30 minutes to prepare a cured sheet.

[0086] [Measurement of Elastic Modulus and Tg] Test pieces with a sample size of 30 mm × 4 mm were prepared using the cured sheets, and the elastic modulus at 20°C and Tg (tan δ peak) were measured using a dynamic viscoelasticity measuring device (manufactured by Anton Paar Japan K.K., product name "MCR702e") under the conditions of a frequency of 1 Hz, a measurement temperature of -40°C to 250°C, and a heating rate of 10°C / min.

[0087] [Linear expansion coefficient] A test piece having a size of 18 mm x 4 mm was prepared from the cured sheet. Using this test piece, the linear expansion coefficient (CTE) was measured using a thermomechanical analyzer (manufactured by Shimadzu Corporation, product name "TMA-60"). The measurement mode was tensile mode, the measurement load was 50 mN, the measurement atmosphere was a nitrogen atmosphere, the temperature range was -50 to 250 ° C, and the heating rate was 5 ° C / min. The measurement result from the second run at -20 to 40 ° C was taken as the CTE.

[0088] [Evaluation of Dielectric Properties] A test piece measuring 60 mm x 100 mm was prepared using the cured sheet. Using this test piece, the relative permittivity (Dk) and dielectric loss tangent (Df) at 10 GHz were measured using a network analyzer (manufactured by KEYSIGHT Technologies, product name "P5003A") and a split cylinder resonator (manufactured by KEYSIGHT Technologies). From the measurement results, evaluation was performed based on the following criteria. When the evaluation result was A or B, it can be said that the dielectric properties were sufficiently low. <Dk Evaluation Criteria> A: Less than 2.5 B: 2.5 or more but less than 2.8 C: 2.8 or more <Df Evaluation Criteria> A: Less than 0.0030 B: 0.0030 or more but less than 0.0050 C: 0.0050 or more

[0089]

[0090]

[0091]

[0092] As is clear from the results shown in Tables 4 and 5, it was confirmed that the resin compositions using the maleimide resins of the Examples had excellent cured product properties, such as low dielectric properties (low Dk and low Df), high Tg, and low CTE. Therefore, use of the maleimide resins of the present disclosure is expected to dramatically improve the properties of laminates such as printed circuit boards and encapsulants for electronic components such as semiconductors.

Claims

1. A maleimide resin obtained by reacting a tetracarboxylic dianhydride (a1), a diamine (a2), a triamine (a3), and maleic anhydride (a4), wherein the tetracarboxylic dianhydride (a1) includes a tetracarboxylic dianhydride having an aromatic ring, the diamine (a2) includes a dimer diamine and a second diamine other than the dimer diamine, and at least one of the second diamine and the triamine includes an amine having an aromatic ring.

2. The maleimide resin according to claim 1, wherein the tetracarboxylic dianhydride having an aromatic ring contains at least one of pyromellitic dianhydride, 4,4'-oxydiphthalic anhydride, 3,4'-oxydiphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, and 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride.

3. The maleimide resin according to claim 1, wherein the amine having an aromatic ring is a diamine having an aromatic ring, and the diamine having an aromatic ring contains at least one of 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2,2'-diethylbiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-diethylbiphenyl, 4,4'-diamino-3,3',5,5'-tetramethylbiphenyl, 4,4'-diamino-3,3',5,5'-tetraethylbiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diamino-2,2'-dimethoxybiphenyl, and 4,4'-diamino-3,3'-dimethoxybiphenyl.

4. The maleimide resin according to claim 1, wherein the diamine contains at least one of a compound represented by the following general formula (1) and a compound represented by the following general formula (2). [In formulas (1) and (2), m, n, p, and q each represent an integer of 1 or more selected so that m + n = 6 to 17 and p + q = 8 to 19, and the bond indicated by a broken line means a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond indicated by a broken line is a carbon-carbon double bond, formulas (1) and (2) have a structure in which the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond is reduced by one from the numbers shown in formulas (1) and (2).] 5. The maleimide resin according to claim 1, having a weight average molecular weight of 3,000 to 100,000.

6. A resin composition comprising the maleimide resin according to any one of claims 1 to 5.

7. The resin composition according to claim 6, further comprising a polymerization initiator.

8. A cured product of the resin composition according to claim 6.

9. A sheet comprising the resin composition according to claim 7 and a substrate.

10. The sheet according to claim 9, wherein the substrate is an organic substrate.

11. The sheet according to claim 9, wherein the substrate is an inorganic substrate.

12. A laminate in which a substrate is further thermocompression-bonded to the adhesive surface of the sheet according to claim 9.

13. A printed wiring board using the sheet according to claim 9.

14. A printed wiring board using the laminate according to claim 12.

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