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

Abstract

The maleimide resin according to the present invention is a maleimide resin obtained by reacting a tetracarboxylic dianhydride (a1) containing a tetracarboxylic dianhydride having an aromatic ring, a diamine (a2) containing a dimer diamine and a second diamine other than the dimer diamine, and maleic anhydride (a4), wherein at least one of the second diamine and a triamine contains an amine having an aromatic ring.

Description

Technical Field

[0001] This invention relates to a maleimide resin, resin composition, cured product, sheet, laminate, and printed circuit board. Background Technology

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

[0003] In recent years, high-frequency electrical signals have been used in these products for high-speed transmission / processing of large amounts of information. However, high-frequency signals are very easy to attenuate. Therefore, in order to suppress transmission loss, insulating materials with excellent dielectric properties are required as insulating materials used in the aforementioned printed circuit boards and multilayer circuit boards.

[0004] As the aforementioned insulating material, epoxy resin compositions disclosed in Patent Documents 1 to 3 are known. Patent Document 1 discloses an epoxy resin composition containing epoxy resin, an active ester compound, and a triazine-containing cresol phenolic varnish resin, which is effective for achieving low dielectric loss tangent. Furthermore, Patent Documents 2 and 3 disclose resin compositions with epoxy resin and an active ester compound as essential components that can form cured products with low dielectric loss tangent, making them useful as insulating materials. However, it has been found that these epoxy resin compositions are unsuitable for high-frequency band applications.

[0005] On the other hand, Patent Document 4 reports the excellent dielectric properties (low relative permittivity and low dielectric loss tangent) of a resin film formed from a resin composition containing a bismaleimide resin with long-chain alkyl groups and a curing agent as a non-epoxy material. However, in bismaleimide resins formed solely from long-chain alkyl diamines, there is a problem of a low glass transition temperature (Tg).

[0006] Previous technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2011-132507 Patent Document 2: Japanese Patent Application Publication No. 2015-101626 Patent Document 3: Japanese Patent Application Publication No. 2017-210527 Patent Document 4: International Publication No. 2016 / 114287 Summary of the Invention

[0007] The technical problem to be solved by the invention Insulating materials used in printed circuit boards, multilayer circuit boards, and rewiring layers of semiconductor PKGs require the formation of cured products with high dielectric constant (Tg). Therefore, an object of the present invention is to provide a novel maleimide resin capable of forming a cured product with high Tg while adequately maintaining a low dielectric constant and low dielectric loss tangent. Another object of the present invention is to provide a resin composition, cured product, sheet, laminate, and printed circuit board using the above-mentioned maleimide resin.

[0008] means for solving technical problems The present invention provides the following maleimide resin, resin composition, cured product, sheet, laminate and printed circuit board.

[0009] [1] A maleimide resin, which is a maleimide resin formed by reacting tetracarboxylic dianhydride (a1), diamine (a2), triamine (a3) ​​and maleic anhydride (a4), wherein the tetracarboxylic dianhydride (a1) comprises a tetracarboxylic dianhydride having an aromatic ring, the diamine (a2) comprises a dimer diamine and a second diamine other than the dimer diamine, and at least one of the second diamine and the triamine comprises an amine having an aromatic ring.

[0010] [2] According to the maleimide resin described in [1] above, wherein the above-mentioned tetracarboxylic dianhydride having an aromatic ring contains at least one of pyromellitic dianhydride, 4,4'-oxobisphthalic anhydride, 3,4'-oxobisphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)bisphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride and 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride.

[0011] [3] According to the maleimide resin described in [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.

[0012] [4] The maleimide resin according to any one of [1] to [3] above, wherein the dimer diamine contains at least one of the compounds represented by the following general formula (1) and the compounds represented by the following general formula (2).

[0013] [In equations (1) and (2), m, n, p, and q represent integers greater than 1 selected in the manner of m+n=6~17 and p+q=8~19, respectively. The bonds represented by dashed lines refer to carbon-carbon single bonds or carbon-carbon double bonds. Among them, when the bonds represented by dashed lines are carbon-carbon double bonds, equations (1) and (2) have the following structure: the structure obtained by subtracting 1 from the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond as shown in equations (1) and (2).] [5] The maleimide resin according to any one of [1] to [4] above has a weight-average molecular weight of 3,000 to 100,000.

[0014] [6] A resin composition comprising the maleimide resin described in any one of [1] to [5] above.

[0015] [7] The resin composition according to [6] above further comprises a polymerization initiator.

[0016] [8] A cured product, which is a cured product of the resin composition described above [6].

[0017] [9] A sheet comprising the resin composition and substrate described in [6] above.

[0018]

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

[0019]

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

[0020]

[12] A laminate formed by further hot-pressing a substrate onto the bonding surface of the sheet described above [9].

[0021]

[13] A printed circuit board made of the sheet described above [9].

[0022]

[14] A printed circuit board made of the laminate described above

[12] .

[0023] Invention Effects According to the present invention, a maleimide resin capable of forming a high Tg cured product can be provided while sufficiently maintaining a low dielectric constant and a low dielectric loss tangent. The present invention also provides a resin composition, cured product, sheet, laminate, and printed circuit board using the above-described maleimide resin.

[0024] The maleimide resin of the present invention and the resin composition (adhesive composition) using the maleimide resin can simultaneously reduce the dielectric constant and dielectric loss tangent (hereinafter, both are sometimes collectively referred to as "dielectric properties"), especially exhibiting excellent low dielectric properties in the high-frequency band. Furthermore, the cured product (adhesive layer) obtained from the above resin composition not only has high elastic modulus and Tg but also excellent toughness. Therefore, the above resin composition is useful as an adhesive used in the manufacture of printed circuit boards (additional substrates, flexible printed circuit boards, etc.) and copper foil for printed circuit boards, and is also useful as an insulating film such as a rewiring layer, a semiconductor interlayer material, a coating agent, a resist ink, a conductive paste, etc. Detailed Implementation

[0025] The preferred embodiments of the present invention will now be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be implemented within its scope.

[0026] In this specification, the numerical range indicated by "~" represents the range encompassed by the values ​​before and after "~" as the minimum and maximum values, respectively. Within the numerical ranges described in stages in this specification, the upper or lower limit of a certain stage's numerical range can be arbitrarily combined with the upper or lower limits of other stages' numerical ranges. Within the numerical ranges described in this specification, the upper or lower limit of the numerical range can be replaced with the values ​​shown in the examples. "A or B" may include either A or B, or both. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination with two or more. When multiple substances belonging to each component exist in the composition, unless otherwise specified, the content of each component in the composition refers to the total amount of the multiple substances present in the composition. In this specification, "solid component" refers to the non-volatile component contained in the resin composition after removing volatile substances (water, solvents, etc.), and also includes components that are liquid, syrupy, or waxy at room temperature (around 25°C).

[0027] [Maleimide resin and resin composition] The maleimide resin of this embodiment is a maleimide resin obtained by reacting tetracarboxylic dianhydride (a1) (hereinafter also referred to as "(a1) component"), diamine (a2) (hereinafter also referred to as "(a2) component"), triamine (a3) ​​(hereinafter also referred to as "(a3) component"), and maleic anhydride (a4) (hereinafter also referred to as "(a4) component"). The (a1) component comprises a tetracarboxylic dianhydride having an aromatic ring, and the (a2) component comprises a dimerized diamine and a second diamine other than a dimerized diamine, wherein at least one of the second diamine and the triamine comprises 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 group (e.g., methyl, ethyl, propyl, etc.) as a substituent.

[0028] The resin composition of this embodiment contains the aforementioned 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)"). Furthermore, the resin composition of this embodiment may further contain an organic solvent (C) (hereinafter also referred to as "component (C)").

[0029] (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 within the molecule.

[0030] (a1) The tetracarboxylic dianhydride of component (a1) includes tetracarboxylic dianhydrides having an aromatic ring. Examples of tetracarboxylic dianhydrides having an aromatic ring include pyromellitic dianhydride, 4,4'-oxobisphthalic anhydride, 3,4'-oxobisphthalic anhydride, 4,4'-(hexafluoroisopropylidene)bisphthalic anhydride, 3,3',4,4'-diphenyl sulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'- Aromatic tetracarboxylic dianhydrides without a fluorene skeleton, such as (4,4'-isopropylidenediphenoxy)bisphthalic anhydride; and tetracarboxylic dianhydrides with 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.

[0031] From the viewpoint of high Tg of the cured product, component (a1) is preferably a tetracarboxylic dianhydride with an aromatic ring, containing at least one of pyromellitic dianhydride, 4,4'-oxobisphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)bisphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride and 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride.

[0032] From the viewpoint of the solubility of maleimide resin and the high Tg of the cured product, it is preferable to use a combination of tetracarboxylic dianhydrides with a fluorene skeleton and aromatic tetracarboxylic dianhydrides without a fluorene skeleton as the tetracarboxylic dianhydride. (a1) The component may include, for example, at least one of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, pyromellitic dianhydride, 4,4'-oxobisphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)bisphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 2,3',3,4'-biphenyltetracarboxylic dianhydride.

[0033] (a1) The component may further comprise a tetracarboxylic dianhydride without an aromatic ring. Examples of tetracarboxylic dianhydrides without an aromatic ring include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)1,4-phenylene, 4,4 '-(acetylene-1,2-diyl)bisphthalic anhydride, 5-(2,5-dioxotetrahydrofuranyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic anhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic anhydride, and 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic anhydride-5,5',6,6'-dianhydride.

[0034] (a2) The ingredients include dimer diamine (the first diamine) and a second diamine other than dimer diamine.

[0035] For example, as described in Japanese Patent Application Publication No. 9-12712, dimer diamines are compounds derived from dimers of unsaturated fatty acids such as oleic acid, i.e., dimer acids. By using dimer diamines as component (a2), the dielectric properties of the cured product can be reduced. In this embodiment, known dimer diamines can be used without particular limitation. Dimer diamines preferably include, for example, at least one of the compounds represented by the following general formula (1) and the compounds represented by the following general formula (2).

[0036] In equations (1) and (2), m, n, p, and q represent integers of 1 or higher selected in the manner of m+n=6~17 and p+q=8~19, respectively. The bonds represented by dashed lines refer to carbon-carbon single bonds or carbon-carbon double bonds. In the case where the bonds represented by dashed lines are carbon-carbon double bonds, equations (1) and (2) are structures obtained by subtracting one from the numbers shown in equations (1) and (2) for the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond.

[0037] As a dimer, diamine can be represented by the above general formula (2) from the viewpoint of solubility in organic solvents, heat resistance, heat-resistant adhesion, low viscosity, etc., and in particular, it can be a compound represented by the following formula (3).

[0038] Commercially available dimerized diamines include, for example, PRIAMINE 1075 and PRIAMINE 1074 (both manufactured by CRODA JAPAN KK). They can be used alone or in combination of two or more.

[0039] The second diamine is a diamine that does not correspond to the dimer diamines mentioned above. The second diamine may include a diamine having an aromatic ring as an amine having an aromatic ring.

[0040] 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, and 4,4'-diamino-2,2'- Diamines with a biphenyl skeleton, such as bis(trifluoromethyl)biphenyl, 4,4'-diamino-2,2'-dimethoxybiphenyl, and 4,4'-diamino-3,3'-dimethoxybiphenyl; diamines with 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 p-phenylenediamine, o-phenylenediamine, and m-phenylenediamine; and 4,4-diphenylamine... Methyldiphenylamine, 4,4'-ethylidene diphenylamine, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-(hexafluoroisopropylidene)diphenylamine, 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)... Bis[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, bis[4-(4-aminophenoxy)phenyl]sulfone, and other bisphenylamine derivatives. They can be used alone or in combination of two or more.

[0041] From the viewpoint of further improving the Tg of the cured product, the diamine having an aromatic ring may contain a diamine having a biphenyl skeleton selected from 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.

[0042] From the viewpoint of further increasing the Tg of the cured product, based on the total amount of components (a2) and (a3), the content of diamines with aromatic rings can be 20 mol% or more, 25 mol% or more, 30 mol% or more, or 35 mol% or more. From the viewpoint of further reducing the dielectric properties of the cured product, it can be 60 mol% or less, 55 mol% or less, 50 mol% or less, or 45 mol% or less.

[0043] The second diamine may include diamines that do not have an aromatic ring. Examples of diamines that do not have an 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-pentanediamine, 2,2,4-trimethylhexane-1,6-diamine, norbornenediamine, and 1,3-bis( Aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornene, 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).

[0044] Examples of triamines that can be used as 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 melamine; heterocyclic triamines such as 1,3,5-triazine-2,4,6-triamine and 2,4,6-triaminopyrimidine; and aromatic triamines 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. They can be used alone or in combination of two or more. From the viewpoint of the solubility of the synthesized component (A) in an organic solvent, an aliphatic triamine is preferred. Furthermore, from the viewpoint of high Tg, tri(2-aminomethyl)amine or tri(2-aminoethyl)amine, which have fewer carbon atoms, are more preferred.

[0045] From the viewpoints of maleimide resin's HAZE, the elastic modulus of the cured product, and Tg, based on the total amount of components (a2) and (a3), the content of component (a3) ​​can be 1 mol% or more, 4 mol% or more, 6 mol% or more, or 8 mol% or more. From the viewpoints of maleimide resin's solubility and HAZE, it can be 30 mol% or less, 25 mol% or less, 20 mol% or less, or 15 mol% or less.

[0046] Using a dimerized diamine as the diamine allows for the formation of a cured product with lower dielectric properties. Conversely, using only a dimerized diamine as the diamine results in a lower Tg and a higher coefficient of linear expansion (CTE) in the cured product. On the other hand, using a triamine improves the solubility of the maleimide resin or increases the residual film rate during photolithography-based pattern formation, facilitates the formation of fine pores, and easily increases the Tg of the cured product by using an amine with an aromatic ring. By using a dimerized diamine, a second diamine, and a triamine, the solubility of the maleimide resin can be improved, and the Tg can be increased while maintaining the dielectric properties of the cured product.

[0047] (A) Component can be manufactured by various known methods. For example, firstly, components (a1), (a2), and (a3) ​​are subjected to an addition reaction at a temperature of about 60–120°C, preferably 70–90°C, typically for about 0.1–2 hours, preferably 0.1–1.0 hours. Next, the obtained adduct is subjected to an imidization reaction, i.e., a dehydration and ring-closure reaction, at a temperature of about 80–250°C, preferably 100–200°C, for about 0.5–30 hours, preferably 0.5–10 hours. Then, the substance that has undergone the dehydration and ring-closure reaction is subjected to a maleimidization reaction, i.e., a dehydration and ring-closure reaction, with component (a4) at a temperature of about 60–250°C, preferably 80–200°C, for about 0.5–30 hours, preferably 0.5–10 hours, thereby obtaining the target component (A).

[0048] In imidization or maleimidization reactions, various known reaction catalysts, dehydrating agents, and organic solvents (described later) 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, methylpyridine, and isoquinoline, or organic acids such as methanesulfonic acid and p-toluenesulfonic acid monohydrate. These can be used alone or in combination of two or more. Examples of dehydrating agents include aliphatic anhydrides such as acetic anhydride and aromatic anhydrides such as benzoic anhydride. These can be used alone or in combination of two or more.

[0049] Component (A) can be purified using various known methods to improve its purity. For example, first, component (A) dissolved in an organic solvent and pure water are added to a separatory funnel. Then, the separatory funnel is shaken and allowed to stand. After the aqueous and organic layers separate, only the organic layer is recovered, thereby purifying component (A).

[0050] The (A) component manufactured 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 (the number of maleimide groups) of the (A) component is based on the content of the triamine, but may be assumed to be 2 to 6 functional groups per molecule. The (A) component may be a mixture of multiple compounds with different structures or different numbers of functional groups. The (A) component may contain compounds that contain one or more structural units represented by the following general formulas (5) to (6) and have 3 or more functional groups per molecule.

[0051] In general formulas (4) to (6), X independently represents a tetravalent organic group, Y independently represents a divalent organic group, and Z independently represents a trivalent organic group. X, Y, and Z can be organic groups with aliphatic groups, alicyclic structures, or aromatic rings, which may contain heteroatoms. Y can be an organic group derived from a dimer diamine, and Z can be an organic group derived from a triamine (a3).

[0052] An example of the hypothetical structure of component (A) produced by the above method is shown in the following general formula (7).

[0053] The meanings of X, Y, and Z in general formula (7) are the same as those in general formulas (4) to (6). Furthermore, a represents an integer from 0 to 20, b represents an integer from 0 to 30, c represents an integer from 0 to 20, and d represents an integer from 1 to 30. In general formula (7), the positions of the structural units with the symbol a (the structural units represented by general formula (5) above), the structural units with the symbol b (the structural units represented by general formula (4) above), and the structural units with the symbol c (the structural units represented by general formula (6) above) can be interchanged. (A) The component may contain compounds in which at least one of a and c is an integer greater than or equal to 1 and each molecule has more than 3 functional groups.

[0054] (A) The molecular weight of component A can be controlled by the molar numbers of components (a1), (a2), and (a3). The smaller the molar number of component (a1) is compared to the total molar number of components (a2) and (a3), the smaller the molecular weight can be. For the purpose of easily achieving the effects of the present invention, the molar number of component (a1) relative to the molar number of components (a2) and (a3), i.e., [molar number of component (a1)] / [molar number of component (a2) + molar number of component (a3)], can generally be about 0.30 to 0.98, preferably 0.40 to 0.96, more preferably 0.50 to 0.94, and even more preferably in the range of 0.60 to 0.90.

[0055] From the viewpoint of solubility in solvents and heat resistance, the molecular weight of component (A), expressed as weight-average molecular weight (Mw), is preferably 3,000 to 100,000, and can 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 the Mw of component (A) is 100,000 or less, its solubility in organic solvents becomes good, and when it is 3,000 or more, it tends to sufficiently improve heat resistance. From this perspective, the lower limit of Mw for component (A) can be above 4000, above 5000, above 6000, above 6500, above 7000, or above 7500, and the upper limit of Mw for component (A) can be below 80000, below 70000, below 60000, below 50000, below 40000, below 36000, below 30000, or below 27000. Mw can be determined by gel permeation chromatography (GPC) and converted using a calibration curve of standard polystyrene.

[0056] (A) The ingredient can be used alone or in combination of two or more.

[0057] (Component (B): Polymerization initiator) As component (B), various known components can be used without particular limitation, as long as they are polymerization initiators that can be used in the resin composition. Specifically, examples of component (B) include organic peroxides, imidazole compounds, phosphine compounds, and phosphonium salt compounds. They 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 performance as polymerization initiators and are also excellent in terms of low dielectric properties.

[0058] Examples of organic peroxides include methyl ethyl ketone peroxide, methyl cyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-hexylperoxy)cyclohexane, 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(4,4-di-tert-butylperoxycyclohexyl)propane, 1,1-bis(tert-butylperoxy)cyclododecane, n-butyl-4,4-bis(tert-butylperoxy)valerate, 2,2-bis(tert-butylperoxy)butane, and 1,1-bis(tert-butylperoxy)cyclododecane. Butylperoxy)-2-methylcyclohexane, tert-butyl hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-hexyl hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, α,α'-bis(tert-butylperoxy)diisopropylbenzene, tert-butylisopropylbenzene peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, cinnamic acid peroxide, m-toluyl (m- Toluoyl peroxide, benzoyl peroxide, diisopropylperoxydicarbonate, bis(4-tert-butylcyclohexyl)peroxydicarbonate, di-3-methoxybutylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, di-sec-butylperoxydicarbonate, di(3-methyl-3-methoxybutyl)peroxydicarbonate, di(4-tert-butylcyclohexyl)peroxydicarbonate, α,α'-bis(neodecanylperoxy)diisopropylbenzene, isopropylbenzene peroxyneodecanate, 1,1,3,3'-tetramethylbutylperoxyneodecanate, 1-cyclohexyl-1-methylethylperoxyneodecanate, tert-hexylperoxyneodecanate, tert-butylperoxyneodecanate Oxylated neodecanoate, tert-hexylperoxyneopentate, tert-butylperoxyneopentate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, tert-hexylperoxy-2-ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyisobutyrate, tert-butylperoxymaleate, tert-butylperoxylaurate, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexyl monocarbonate, 2,5-dimethyl-2,5-Di(benzoylperoxy)hexane, tert-butylperoxyacetic acid ester, tert-hexylperoxybenzoate, tert-butylperoxym-toluylbenzoate, tert-butylperoxybenzoate, bis(tert-butylperoxy)isophthalate, tert-butylperoxyallyl monocarbonate, and 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone. These can be used alone or in combination of two or more. Among these organic peroxides, dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and α,α'-bis(tert-butylperoxy)diisopropylbenzene are preferred.

[0059] Examples of imidazole compounds include 2-ethyl-4-methylimidazolium, 2-methylimidazolium, 2-ethylimidazolium, 2,4-dimethylimidazolium, 2-undecaprolimidazole, 2-heptadecylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, 1-vinyl-2-methylimidazolium, 1-propyl-2-methylimidazolium, 2-isopropylimidazolium, 1-cyanomethyl-2-methylimidazolium, 1-cyanoethyl-2-ethyl-4-methylimidazolium, 1-cyanoethyl-2-undecaprolimidazole, and 1-cyanoethyl-2-phenylimidazolium. Among these, 1-cyanoethyl-2-phenylimidazolium and 2-ethyl-4-methylimidazolium have high solubility in the resin composition of this embodiment and are therefore preferred. They can be used alone or in combination of two or more.

[0060] Examples of phosphine compounds include primary phosphine, secondary phosphine, and tertiary phosphine. Examples of primary phosphine include alkylphosphines such as ethylphosphine and propylphosphine, and phenylphosphine. Examples of secondary phosphine include dialkylphosphines such as dimethylphosphine and diethylphosphine, diphenylphosphine, methylphenylphosphine, and ethylphenylphosphine. Examples of tertiary phosphine include trialkylphosphines such as trimethylphosphine, triethylphosphine, tributylphosphine, and trioctylphosphine, tricyclohexylphosphine, triphenylphosphine, alkyldiphenylphosphine, dialkylphenylphosphine, tribenzylphosphine, trimethylstyrylphosphine, tri-p-styrylphosphine, tris(2,6-dimethoxyphenyl)phosphine, tri-4-methylphenylphosphine, tri-4-methoxyphenylphosphine, and tri-2-cyanoethylphosphine. Tertiary phosphines are preferred. They can be used alone or in combination of two or more.

[0061] Examples of phosphonium salt compounds include those having tetraphenylphosphonium salts, alkyltriphenylphosphonium salts, and tetraalkylphosphonium, specifically tetraphenylphosphonium-thiocyanate, tetraphenylphosphonium-tetra-p-methylphenylborate, butyltriphenylphosphonium-thiocyanate, tetraphenylphosphonium-phthalic acid, tetrabutylphosphonium-1,2-cyclohexyldicarboxylic acid, tetrabutylphosphonium-1,2-cyclohexyldicarboxylic acid, and tetrabutylphosphonium-lauric acid. These compounds can be used alone or in combination of two or more.

[0062] The content of component (B) is not particularly limited, but relative to 100 parts by mass of component (A), it can 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.

[0063] (C) Component: Organic solvent) As for component (C), there are no particular limitations as long as it dissolves component (A). Examples of components (C) include aromatic hydrocarbon solvents such as benzene, toluene, xylene, mesitylene, 1,2,4-trimethylbenzene, and anisole; alcohol solvents such as methanol, ethanol, isopropanol, butanol, pentanol, hexanol, propylene glycol, and phenol; ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanol, hexanone, cyclopentanone, cyclohexanone, isophorone, and acetophenone; cellosols such as methyl cellosol and ethyl cellosol; and methyl acetate and acetic acid. Ester solvents such as ethyl acetate, butyl acetate, methyl propionate, butyl formate, and γ-butyrolactone; glycol ether solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether; and amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone. One or more of these solvents can be used. Among these, aromatic hydrocarbons with high solubility for component (A), such as toluene, mesitylene, and 1,2,4-trimethylbenzene, are preferred.

[0064] (C) There is no particular limitation on the amount of component used, but it is generally acceptable to use a non-volatile component of the resin composition in this embodiment that is in the range of about 20 to 65% by mass.

[0065] The resin composition of this embodiment is prepared according to commonly used methods. Examples of preparation methods include melt mixing, powder mixing, and solution mixing. Furthermore, without impairing the effects of the present invention, other components besides those necessary for this embodiment, such as release agents, flame retardants, ion traps, antioxidants, adhesion promoters, stress reducers, colorants, coupling agents, and inorganic fillers, can be incorporated. Furthermore, the resin composition of this embodiment may contain resins other than those in component (A), such as epoxy resins, acrylate compounds, vinyl compounds, benzoxazine compounds, and maleimide compounds other than those in component (A).

[0066] (Mold release agent) Regarding mold release agents, they are added to improve the release properties from the mold. Examples of mold release agents include carnauba wax, rice bran wax, candelilla wax, polyethylene, oxidized polyethylene, polypropylene, linalic acid, esters of linalic acid with saturated alcohols, 2-(2-hydroxyethylamino)ethanol, ethylene glycol, glycerin, etc., i.e., linalool, stearic acid, stearate esters, stearamide, and all other known mold release agents. They can be used alone or in combination of two or more.

[0067] (Flame retardant) Regarding flame retardants, all known flame retardants can be used to impart flame retardancy, and there are no particular limitations. Examples of flame retardants include phosphazene compounds, silicon compounds, zinc molybdate-supported talc, zinc molybdate-supported zinc oxide, aluminum hydroxide, magnesium hydroxide, and molybdenum oxide. They can be used alone or in combination of two or more.

[0068] (Ion scavenger) Ion scavengers are added to capture ionic impurities contained in liquid resin compositions and to prevent thermal and hygroscopic degradation. All known ion scavengers can be used without particular limitation. Examples of ion scavengers include hydrotalcites, bismuth hydroxide compounds, and rare earth oxides. They can be used alone or in combination of two or more.

[0069] (Inorganic packing) Regarding inorganic fillers, various known inorganic fillers can be used without particular limitation, as long as they are suitable for use in resin compositions. 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 whiskers, boron nitride, silicon dioxide, graphite powder, and boehmite. Among these, silicon dioxide is particularly preferred due to its excellent low dielectric loss tangent. One type of inorganic filler can be used alone, or in combination of two or more.

[0070] The average particle size of the inorganic filler can be 50 nm or more, 100 nm or more, or 200 nm or more, or it can be less than 10 μm, 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. If the average particle size of the inorganic filler is within the above range, the surface roughness of the sheet can be reduced, and the adhesion to substrates such as polyimide film and copper foil can be improved.

[0071] The average particle size of the aforementioned inorganic filler is taken as the median particle size (d50) that represents 50% of the cumulative particle size in the volumetric cumulative particle size distribution. This average particle size can be measured using a particle size distribution measuring device based on laser diffraction scattering.

[0072] The inorganic filler is preferably surface-treated, preferably a surface-treated material based on a coupling agent, and more preferably a surface-treated material based on a silane coupling agent. By surface-treating the above-mentioned inorganic filler, not only can the dispersibility of the inorganic filler in organic solvents be improved, but the surface roughness of the sheet surface is further reduced, thereby improving the adhesion to substrates such as polyimide films and copper foils.

[0073] Examples of coupling agents include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the aforementioned silane coupling agents include methacrylsilane, acryloylsilane, aminosilane, phenylaminosilane, imidazolesilane, phenylsilane, vinylsilane, and epoxysilane. They can be used alone or in combination of two or more.

[0074] When the resin composition contains inorganic fillers, the content can be 5–75% by mass, 5–50% by mass, 5–35% by mass, or 10–30% by mass, based on the total amount of solid components (non-volatile components) of the resin composition (100% by mass). If the content of inorganic fillers is 75% by mass or less, there is a tendency to suppress the reduction of adhesion; if the content of inorganic fillers is 5% by mass or more, there is a tendency to fully obtain the effect of reducing dielectric loss tangent and improving heat resistance.

[0075] [cured material] 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.

[0076] The shape of the cured material in this embodiment is not particularly limited, but when used for bonding substrates, the film thickness can usually be set to about 1 to 200 μm, preferably a sheet of about 3 to 100 μm, and the film thickness can be adjusted appropriately according to the application.

[0077] [Sheet] The sheet of this embodiment comprises the resin composition and substrate of this embodiment. The sheet of this embodiment is obtained, for example, by coating the resin composition of this embodiment onto a substrate (sheet substrate) and drying it. Examples of such substrates include organic substrates such as polyimide, polyimide-silica mixtures, 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), polyethylene terephthalate, phenol, phthalic acid, hydroxynaphthalic acid, and p-hydroxybenzoic acid, such as aromatic polyester resins (so-called liquid crystal polymers: manufactured by KURARAY CO., LTD., "Vexter", etc.). Among these, polyimide films, and especially polyimide-silica mixture films, are preferred in terms of heat resistance and dimensional stability. Furthermore, the aforementioned substrates can be made of metals such as glass, iron, aluminum, 42 alloy, and copper, or inorganic substrates such as ITO, silicon, and silicon carbide. The thickness of the aforementioned substrates can be appropriately set according to the application.

[0078] [Layered Body] The laminate of this embodiment is obtained by further hot-pressing a substrate onto the bonding surface of the aforementioned sheet. As this substrate, organic substrates such as polyimide, polyimide-silica mixtures, polyamide, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polystyrene resin (PSt), polycarbonate resin (PC), acrylonitrile-butadiene-styrene resin (ABS), polyethylene terephthalate, phenol, phthalic acid, hydroxynaphthalic acid, and aromatic polyester resins (liquid crystal polymers) obtained from p-hydroxybenzoic acid can be used. Furthermore, inorganic substrates such as glass, iron, aluminum, alloy 42, copper, ITO, silicon, and silicon carbide can also be used. The thickness of the substrate can be appropriately set according to the application. Furthermore, the laminate can be further subjected to heat treatment.

[0079] [Printed substrates and printed circuit boards] The printed circuit board of this embodiment uses the aforementioned sheet or the aforementioned laminate. The printed circuit board of this embodiment is obtained, for example, by further bonding the adhesive surface of the aforementioned sheet to the inorganic substrate surface of the aforementioned laminate. Preferably, a polyimide film is used as the organic substrate and a metal foil (especially copper foil) is used as the inorganic substrate. Furthermore, a circuit is formed by soft etching the metal surface of the printed circuit board, and the aforementioned sheet is further bonded thereon and hot-pressed, thereby obtaining a printed circuit board.

[0080] Example The present invention will now be specifically described through examples and comparative examples, but the present invention is not limited thereto. Furthermore, in each example, unless otherwise specified, parts and percentages refer to quality standards.

[0081] Synthesis of maleimide resin To synthesize maleimide resin, the following components (a1) to (a4), acid catalyst and solvent were prepared.

[0082] ((a1) ingredient) BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorenic dianhydride (manufactured by JFE Chemical Corporation, product name "BPAF") PMDA: Pyromellitic dianhydride (manufactured by DAIICEL CORPORATION) ODPA: 4,4'-O-diphthalic anhydride (Manac Inc., product name "ODPA") s-BPDA: 3,3',4,4'-Biphenyltetracarboxylic acid dianhydride (manufactured by JFE Chemical Corporation, product name "BPDA") a-BPDA: 2,3',3,4'-Biphenyltetracarboxylic acid dianhydride (manufactured by JFE Chemical Corporation, product name "a-BPDA") BISDA: 4,4'-(4,4'-isopropylidene diphenoxy)bisphthalic anhydride (manufactured by SABIC, product name "BISDA-1000") (a2) component) DDA: Dimeric diamine (manufactured by CRODA JAPAN KK, product name "PRIAMINE1075") mTBHG: 4,4'-Diamino-2,2'-Dimethylbiphenyl (manufactured by Wakayama Seika Co., Ltd., product name "m-TB-HG") NBDA: Norbornene Diamine (manufactured by Mitsui Chemicals Fine Chemicals Inc.) (a3) component) 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.) (a4) component) Maleic anhydride (manufactured by FUJI SANGYO CO., LTD.) (Acid catalyst) Mesylate aqueous solution (manufactured by BASF, product name "Lutropur MSA") (solvent) 1,2,4-Trimethylbenzene (manufactured by TOYOBO CO., LTD., an aromatic high-boiling-point solvent) Solmix A-11 (manufactured by Nippon Alcohol Co., Ltd., an alcohol-based solvent) γ-Butyrolactone (manufactured by FUJIFILM Wako Pure Chemical Corporation) Toluene (manufactured by Yamaichi Chemical Industries Co., Ltd.) (Synthesis example 1) In a 0.3L flask equipped with a cooler, nitrogen inlet tube, thermocouple, and stirrer, 16.87 parts by weight of 9,9-bis(3,4-dicarboxyphenyl)fluorenic dianhydride (BPAF), 10.82 parts by weight of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA), 127.03 parts by weight of 1,2,4-trimethylbenzene, 36.27 parts by weight of Solmix A-11, and 29.91 parts by weight of γ-butyrolactone were added. After addition, the temperature was raised to 80°C and maintained for 0.5 hours. Then, 26.33 parts by weight of dimerized diamine (DDA) were added dropwise, followed by 0.96 parts by weight of tris(2-aminoethyl)amine (TAEA), and finally 8.33 parts by weight of 4,4'-diamino-2,2'-dimethylbiphenyl (mTBHG). After addition, 2.47 parts by weight of an aqueous solution of methanesulfonic acid were added, and the temperature was raised to 160°C. Following this, 40.00 parts by weight of toluene were added, and a dehydration and ring-closure reaction was carried out at 160°C for 3 hours to remove water and alcohol from the reaction solution, yielding the intermediate polyimide resin. Next, the polyimide resin was cooled to 130°C, and 7.21 parts by weight of maleic anhydride were added. The temperature was raised to 160°C, and a dehydration and ring-closure reaction was carried out at 160°C for 4 hours to remove water from the reaction solution, yielding the maleimide resin.

[0083] Maleimide resin was added to a separatory funnel, along with 500 parts by weight of pure water. The funnel was shaken to mix the mixture, and then allowed to stand. After standing, the aqueous and organic layers separated, and only the organic layer was recovered. The recovered organic layer was placed into a 1L glass container equipped with a cooler, a nitrogen inlet pipe, a thermocouple, a stirrer, and a vacuum pump. The container was heated to 88–93°C to remove the water, and then heated to 100°C. The solvent was partially removed for 0.5 hours under a pressure reduction of 0.1 MPa from atmospheric pressure, yielding a solution of maleimide resin (A-1) of component (A).

[0084] (Synthesis Example 2 to Synthesis Example 9) As shown in Table 1, the proportions of each component were changed, and otherwise, solutions of maleimide resins (A-2) to (A-9) were obtained in the same manner as in Synthesis Example 1.

[0085] (Synthesis Examples 10 to 16) As shown in Table 2, the proportions of each component were changed, and otherwise, solutions of maleimide resins (A-10) to (A-16) were obtained in the same manner as in Synthesis Example 1.

[0086] (Compare Synthetic Examples 1-4) As shown in Table 3, the proportions of each component were changed, and otherwise, solutions of maleimide resins (A-17) to (A-20) were obtained in the same manner as in Synthesis Example 1.

[0087] (Non-volatile components) The solutions of maleimide resins (A-1) to (A-20) were weighed at 0.75 g ± 0.25 g on a metal petri dish using a precision balance, and then dried at 150 °C for 0.5 hours using a hot air dryer. The non-volatile component (NV) was calculated using the following formula.

[0088] NV (mass%) = {(W3-W1) / W2} × 100 W1: Mass of the empty metal petri dish (g) W2: Mass (g) of the maleimide resin solution before drying. W3: Mass (g) of dried metal petri dish + maleimide resin (weight-average molecular weight) The weight-average molecular weight (Mw) of maleimide resin was determined by GPC (gel permeation chromatography). Samples containing maleimide resin dissolved in tetrahydrofuran (THF) at a concentration of 3% by mass were injected in 50 μL into columns heated to 30 °C (one GL-R420 (manufactured by Hitachi High-Tech Corporation), one GL-R430 (manufactured by Hitachi High-Tech Corporation), and one GL-R440 (manufactured by Hitachi High-Tech Corporation). THF was used as the developing solvent, and measurements were performed at a flow rate of 1.6 mL / min. An L-3350 RI detector (manufactured by Hitachi, Ltd.) was used as the detector, and Mw was calculated based on the dissolution time using a molecular weight / dissolution time curve prepared using standard polystyrene (manufactured by TOSOHCORPORATION). In addition, since the maleimide resin (A-17) of Comparative Synthesis Example 2 and the maleimide resin (A-20) of Comparative Synthesis Example 4 are insoluble in THF, Mw could not be determined.

[0089] (HAZE) The turbidity of the maleimide resin solution was measured using a haze meter (manufactured by NIPPON DENSHOKUINDUSTRIES Co., Ltd., product name "NDH8000"). The maleimide resin solution was poured into a quartz cuvette with a width of 1.0 cm, a width of 3.6 cm, and a height of 5.5 cm, and measured after standard calibration with pure water. Furthermore, the maleimide resins of Comparative Synthesis Example 2 (A-17) and Comparative Synthesis Example 4 (A-20) could not be measured because they were insoluble in the solvent.

[0090] (Solubility) Regarding the solubility of maleimide resin, a solution of maleimide resin was added to a 20 mL screw-top tube, and the presence of any precipitate or turbidity was visually confirmed. Solubility was evaluated as follows: a solution with neither precipitate nor turbidity was rated "A"; a solution with no precipitate but turbidity was rated "B"; and a solution with precipitate was rated "C".

[0091] [Table 1]

[0092] [Table 2]

[0093] [Table 3]

[0094] [Examples 1 to 16 and Comparative Examples 1 to 4] (Preparation of the resin composition) The maleimide resin compositions of the examples were prepared by mixing the components shown below with the compositions shown in Table 4 or Table 5, and the maleimide resin compositions of the comparative examples were prepared by mixing the components shown below with the compositions shown in Table 6. The mixing amounts of components (A) shown in Tables 4 to 6 represent the mixing amounts (parts by mass) including solvent. Furthermore, regarding the maleimide resin compositions of Comparative Examples 2 and 4, the maleimide resin was not soluble in the solvent, therefore evaluation was not possible.

[0095] (A) Composition: Maleimide resin (A-1) ~ (A-20) (B) Ingredients: DCP (manufactured by NIPPON OIL CORPORATION, product name "Parkmill D", dicumyl peroxide) (C) Ingredients: 1,2,4-Trimethylbenzene (manufactured by TOYOBO CO., LTD., an aromatic high-boiling-point solvent) (Preparation of cured sheets) Using an applicator, the aforementioned maleimide resin composition was coated onto a Cu foil (manufactured by MITSUI MINING & SMELTING CO.,LTD., product name "3EC-M2S-VLP") to achieve a thickness of 100 μm after drying. The foil was then dried at 130°C for 30 minutes using a dryer. Next, it was cured at 200°C for 1 hour using a nitrogen dryer. After curing, the foil was cooled to room temperature, and the copper foil was removed by etching with an ammonium persulfate aqueous solution. The cured sheet was then dried at 110°C for 30 minutes.

[0096] [Determination of Elastic Modulus and Tg] Test specimens with a sample size of 30mm × 4mm were prepared using cured sheets. The elastic modulus and Tg (tanδ peak value) at 20℃ were measured using a dynamic viscoelasticity measuring device (manufactured by Anton Paar Japan KK, product name "MCR702e") at a frequency of 1Hz, a measurement temperature of -40℃ to 250℃, and a heating rate of 10℃ / min.

[0097] [Coefficient of linear expansion] Test specimens with dimensions of 18 mm × 4 mm were fabricated from cured sheets. Using these specimens, the coefficient of linear expansion (CTE) was determined using a thermomechanical analysis apparatus (manufactured by Shimadzu Corporation, product name "TMA-60"). The measurement mode was tensile, the load was 50 mN, the atmosphere was nitrogen, the temperature range was -50 to 250 °C, and the heating rate was 5 °C / min. The results from the second round of measurements at -20 to 40 °C were taken as the CTE.

[0098] [Evaluation of dielectric properties] Test pieces measuring 60 mm × 100 mm were fabricated using cured sheets. Using these test pieces, the relative permittivity (Dk) and dielectric loss tangent (Df) at 10 GHz were measured using a network analyzer (KEYSIGHT Technologies, product name "P5003A") and a split cylindrical resonator (KEYSIGHT Technologies). Based on the measurement results, evaluations were performed according to the following criteria. A result of A or B indicates that the dielectric properties are sufficiently low.

[0099] <Dk Judgment Criteria> A: Less than 2.5 B: 2.5 or higher and less than 2.8 C: 2.8 and above <Df Judgment Criteria> A: Less than 0.0030 B: 0.0030 or higher and less than 0.0050 C: Above 0.0050 [Table 4]

[0100] [Table 5]

[0101] [Table 6]

[0102] As clearly shown in Tables 4 and 5, the resin compositions using the maleimide resin of the examples exhibit excellent low dielectric properties (low Dk and low Df), high Tg, and low CTE as cured products. Therefore, by using the maleimide resin of the present invention, it is expected that the properties of sealing materials for laminates such as printed circuit boards and electronic components such as semiconductors can be significantly improved.

Claims

1. A maleimide resin, which is a maleimide resin prepared by reacting tetracarboxylic dianhydride (a1), diamine (a2), triamine (a3) ​​and maleic anhydride (a4), wherein, The tetracarboxylic dianhydride (a1) comprises a tetracarboxylic dianhydride having an aromatic ring. The diamine (a2) comprises a dimer diamine and a second diamine other than the dimer diamine. At least one of the second diamine and the triamine comprises an amine having an aromatic ring.

2. The maleimide resin according to claim 1, wherein, The aromatic ring-containing tetracarboxylic dianhydride contains at least one of pyromellitic dianhydride, 4,4'-oxobisphthalic anhydride, 3,4'-oxobisphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)bisphthalic 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 dimer diamine contains at least one of the compounds represented by general formula (1) and general formula (2). In equations (1) and (2), m, n, p and q represent integers of 1 or more selected in the manner of m+n=6~17 and p+q=8~19 respectively. The bond represented by the dashed line refers to a carbon-carbon single bond or a carbon-carbon double bond. In the case where the bond represented by the dashed line is a carbon-carbon double bond, equations (1) and (2) have the following structure: the structure obtained by subtracting 1 from the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond as shown in equations (1) and (2).

5. The maleimide resin according to claim 1, wherein the weight-average molecular weight is 3000 to 100000.

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, which is a cured product of the resin composition of claim 6.

9. A sheet comprising the resin composition and substrate of claim 7.

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 formed by further hot-pressing a substrate onto the bonding surface of the sheet of claim 9.

13. A printed circuit board made using the sheet of claim 9.

14. A printed circuit board comprising the laminate of claim 12.

Images