CN113748149B - Curable resin composition - Google Patents

Abstract

Provided are: a curable resin composition whose cured product has both excellent heat resistance and dielectric properties, a cured product thereof, a prepreg, a circuit board, a laminate film, a semiconductor sealing material, and a semiconductor device having both these properties. The curable resin composition of the present invention is characterized in that it contains: a maleimide (A) having an indane skeleton, and a polyphenylene ether compound (B) having a reactive double bond.

Description

Curable resin composition

Technical Field

The present invention relates to a curable resin composition, a cured product obtained from the curable resin composition, a prepreg, a circuit board, a build-up film, a semiconductor sealing material, and a semiconductor device.

Background Art

As materials for circuit boards for electronic devices, prepregs obtained by impregnating glass cloth with thermosetting resins such as epoxy resins and BT (bismaleimide-triazine) resins and then heating and drying, laminates obtained by heating and curing the prepregs, and multilayer boards obtained by combining the laminates and the prepregs and then heating and curing them are widely used. Among them, semiconductor package substrates are becoming increasingly thinner, and warping of the package substrate during installation has become a problem. Therefore, in order to suppress this problem, materials showing high heat resistance are required.

In recent years, the speed and frequency of signals have been increasing, and it has been desired to provide a thermosetting resin composition that can provide a cured product that maintains a sufficiently low dielectric constant under these environments and exhibits a sufficiently low dielectric loss tangent.

Particularly, recently, in various electronic material applications, especially advanced material applications, further improvements in performance represented by heat resistance and dielectric properties, and materials and compositions having both of these performances are required.

In response to the above requirements, maleimide resins are attracting attention as materials that have both heat resistance and low dielectric constant/low dielectric loss tangent. However, although conventional maleimide resins have high heat resistance, their dielectric constant/dielectric loss tangent values have not reached the level required for advanced material applications, and they have poor handling properties due to poor solvent solubility. Therefore, there is a strong desire to develop a resin that maintains heat resistance, exhibits a further low dielectric constant/low dielectric loss tangent, and has excellent solvent solubility.

Among them, as a cyanate ester material having both high dielectric properties and heat resistance, a resin composition obtained by blending a phenol novolac cyanate resin, a bisphenol A cyanate resin, and a non-halogen epoxy resin is known (see Patent Document 1).

However, although the heat resistance and dielectric properties of the cured product of the resin composition described in Patent Document 1 are improved to some extent, the heat resistance has not yet reached the level required in recent years.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2004-182850

Summary of the invention

Problem that the invention aims to solve

Therefore, the problem to be solved by the present invention is to provide a curable resin composition whose cured product has excellent heat resistance and dielectric properties, and its cured product, a prepreg, a circuit board, a laminated film, a semiconductor sealing material, and a semiconductor device having the above properties.

Solutions for solving problems

Therefore, the present inventors conducted intensive studies to solve the above-mentioned problems and found that a cured product of a curable resin composition containing a maleimide (A) having an indane skeleton and a polyphenylene ether compound (B) having a reactive double bond can have a low dielectric constant and a low dielectric loss tangent and also have excellent heat resistance, thereby completing the present invention.

That is, the present invention relates to a curable resin composition characterized by containing a maleimide (A) having an indane skeleton and a polyphenylene ether compound (B) having a reactive double bond.

In the curable resin composition of the present invention, the maleimide (A) is preferably represented by the following general formula (1).

(In formula (1), Ra each independently represents an alkyl group, alkoxy group or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group or a mercapto group, and q represents an integer of 0 to 4. When q is 2 to 4, Ra can be the same or different in the same ring. Rb each independently represents an alkyl group, alkoxy group or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group or a mercapto group, and r represents an integer of 0 to 3. When r is 2 to 3, Rb can be the same or different in the same ring. n is the average number of repeating units and represents a value of 0.5 to 20.)

The cured product of the present invention is preferably obtained by subjecting the aforementioned curable resin composition to a curing reaction.

The prepreg of the present invention preferably comprises a reinforcing base material and a semi-cured product of the curable resin composition impregnated into the reinforcing base material.

The circuit board of the present invention is preferably obtained by laminating the above-mentioned prepreg and copper foil and subjecting them to thermal compression molding.

The laminated film of the present invention preferably contains the aforementioned curable resin composition.

The semiconductor sealing material of the present invention preferably contains the above-mentioned curable resin composition.

The semiconductor device of the present invention preferably includes a cured product obtained by heating and curing the semiconductor sealing material.

Effects of the Invention

The curable resin composition of the present invention is useful for providing a cured product obtained from the curable resin composition having both excellent heat resistance and dielectric properties, and a cured product obtained from the curable resin composition having the above-mentioned properties, a prepreg, a circuit board, a laminated film, a semiconductor sealing material, and a semiconductor device.

DETAILED DESCRIPTION

Hereinafter, the present invention will be described in detail.

The present invention relates to a curable resin composition, characterized in that it contains: a maleimide (A) having an indane skeleton and a polyphenylene ether compound (B) having a reactive double bond. Wherein, the maleimide (A) is preferably represented by the following general formula (1). The maleimide (A) has an indane skeleton, so that compared with conventional maleimides, the proportion of polar functional groups in the structure of the maleimide (A) is small, so the dielectric properties are excellent, and therefore it is preferred. In addition, the cured product using conventional maleimide resins tends to be brittle, and there is a concern that the brittleness resistance is poor, but the maleimide (A) has an indane skeleton, so it is excellent in flexibility, and it is also expected that the brittleness resistance will be improved, which is preferred.

In the above general formula (1), Ra each independently represents an alkyl group, alkoxy group or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms (preferably 5 to 10 carbon atoms), a halogen atom, a nitro group, a hydroxyl group or a mercapto group, and q represents an integer value of 0 to 4. When q is 2 to 4, Ra may be the same or different in the same ring. Rb each independently represents an alkyl group, alkoxy group or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group or a mercapto group, and r represents an integer value of 0 to 3. When r is 2 to 3, Rb may be the same or different in the same ring. n represents the average number of repeating units, and represents a value of 0.5 to 20. It should be noted that when the aforementioned r and the aforementioned q are 0, Ra and Rb each refer to a hydrogen atom.

Ra in the above general formula (1) is preferably any one of an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms. By using the above-mentioned alkyl group having 1 to 4 carbon atoms, etc., the solvent solubility is improved due to the reduction of planarity and crystallinity near the maleimide group, and a preferred mode can be obtained without damaging the reactivity of the maleimide group.

In the general formula (1), q is preferably 2 to 3, more preferably 2. When q is 2, the influence of steric hindrance is small and the electron density on the aromatic ring is increased, which is a preferred embodiment in the production (synthesis) of maleimide.

Preferably, in the general formula (1), r is 0 and Rb is a hydrogen atom. In addition, preferably, r is 1 to 3 and Rb is at least one selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms. In particular, by making the aforementioned r 0 and Rb a hydrogen atom, the steric hindrance during the formation of the indane skeleton in the maleimide is reduced, which is beneficial for the production (synthesis) of maleimide and is a preferred embodiment.

<Method for producing maleimide (A) having an indane skeleton>

The method for producing the maleimide (A) will be described below.

The following general formula (2) is the following compound: Rc each independently represents a monovalent functional group selected from the group consisting of the following general formulae (3) and (4), at least one of the two Rc's is ortho to a hydrogen atom, and Rb and r have the same meanings as above.

The following general formula (5) is: at least one of the ortho and para positions of the amino group is a hydrogen atom, Ra and q respectively represent aniline or its derivatives having the same meanings as above, and by reacting the compound of the above general formula (2) with the compound of the following general formula (5) in the presence of an acid catalyst, an intermediate amine compound represented by the following general formula (6) can be obtained. It should be noted that Ra, Rb, q, and r in the following general formula (6) have the same meanings as above.

The intermediate amine compound represented by the general formula (6) includes the following general formula (7) having an indane skeleton in its structure, but in the case of the aniline or its derivative represented by the general formula (5), when q is 3 or less and at least two of the ortho and para positions of the amino group are hydrogen atoms, the structure is represented by the following general formula (8). In the following general formula (8), Ra, Rb, q and r are the same as those described above, and m is the number of repeating units, which represents an integer value of 1 to 20. In addition, the structure represented by the following general formula (8) may also be included in the structure of the general formula (6).

In the indane skeleton (refer to the above general formula (7)) which is a characteristic of the maleimide (A) used in the present invention, the average number of repeating units n is 0.5 to 20, preferably 0.7 to 10.0, more preferably 0.95 to 10.0, further preferably 0.98 to 9.0, further preferably 0.99 to 8.0, further preferably 1.0 to 7.0, further preferably 1.0 to 6.0, in order to achieve a low melting point (low softening point), a low melt viscosity, and excellent handling properties. By having an indane skeleton in the structure of the maleimide (A), it is excellent in solvent solubility compared to conventionally used maleimides, which is a preferred embodiment. It should be noted that when the aforementioned n is less than 0.5, the content ratio of the high melting point substance in the structure of the aforementioned maleimide (A) becomes high, the solvent solubility is poor, and the ratio of the high molecular weight component that contributes to the flexibility becomes low, so there is a concern that the brittleness resistance of the obtained cured product is reduced, and the flexibility and softness are also reduced, which is not preferred. In addition, when the aforementioned n exceeds 20, there is a concern that the heat resistance is poor, and the high molecular weight component becomes too much, and there is a concern that the fluidity is reduced and the handling is poor when the cured product is formed, which is not preferred. In addition, as the value of the aforementioned n, from the viewpoint of high heat deformation temperature, high glass transition temperature, etc., it is preferably 0.5 to 10.0, and more preferably 0.95 to 10.0.

The compound represented by the general formula (2) used in the present invention (hereinafter, "compound (a)") is not particularly limited, and typically, p-diisopropenylbenzene and m-diisopropenylbenzene, p-bis(α-hydroxyisopropyl)benzene and m-bis(α-hydroxyisopropyl)benzene, 1-(α-hydroxyisopropyl)-3-isopropenylbenzene, 1-(α-hydroxyisopropyl)-4-isopropenylbenzene or a mixture thereof are used. In addition, core alkyl substituted products of these compounds, such as diisopropenyltoluene and bis(α-hydroxyisopropyl)toluene, etc., may also be used, and core halogen substituted products, such as chlorodiisopropenylbenzene and chlorobis(α-hydroxyisopropyl)benzene, etc. may also be used.

Examples of the compound (a) include 2-chloro-1,4-diisopropenylbenzene, 2-chloro-1,4-bis(α-hydroxyisopropyl)benzene, 2-bromo-1,4-diisopropenylbenzene, 2-bromo-1,4-bis(α-hydroxyisopropyl)benzene, 2-bromo-1,3-diisopropenylbenzene, 2-bromo-1,3-bis(α-hydroxyisopropyl)benzene, 4-bromo-1,3-diisopropylbenzene, 4-bromo-1,3-bis(α-hydroxyisopropyl)benzene, 5-bromo-1,3-diisopropenylbenzene, Isopropenylbenzene, 5-bromo-1,3-bis(α-hydroxyisopropyl)benzene, 2-methoxy-1,4-diisopropenylbenzene, 2-methoxy-1,4-bis(α-hydroxyisopropyl)benzene, 5-ethoxy-1,3-diisopropenylbenzene, 5-ethoxy-1,3-bis(α-hydroxyisopropyl)benzene, 2-phenoxy-1,4-diisopropenylbenzene, 2-phenoxy-1,4-bis(α-hydroxyisopropyl)benzene, 2,4-diisopropenylbenzenethiol, 2,4-bis(α-hydroxyisopropyl)benzene Benzenethiol, 2,5-diisopropenylbenzenethiol, 2,5-bis(α-hydroxyisopropyl)benzenethiol, 2-methylthio-1,4-diisopropenylbenzene, 2-methylthio-1,4-bis(α-hydroxyisopropyl)benzene, 2-phenylthio-1,3-diisopropenylbenzene, 2-phenylthio-1,3-bis(α-hydroxyisopropyl)benzene, 2-phenyl-1,4-diisopropenylbenzene, 2-phenyl-1,4-bis(α-hydroxyisopropyl)benzene, 2-cyclopentyl-1,4-diisopropenylbenzene, 2-cyclopentyl-1,4-diisopropenylbenzene, Pentyl-1,4-bis(α-hydroxyisopropyl)benzene, 5-naphthyl-1,3-diisopropenylbenzene, 5-naphthyl-1,3-bis(α-hydroxyisopropyl)benzene, 2-methyl-1,4-diisopropenylbenzene, 2-methyl-1,4-bis(α-hydroxyisopropyl)benzene, 5-butyl-1,3-diisopropenylbenzene, 5-butyl-1,3-bis(α-hydroxyisopropyl)benzene, 5-cyclohexyl-1,3-bis(α-hydroxyisopropyl)benzene, etc.

It should be noted that the substituent contained in the aforementioned compound (a) is not particularly limited, and the compounds exemplified above can be used. In the case of a substituent with large steric hindrance, compared with a substituent with small steric hindrance, it is less likely for the obtained maleimides to stack with each other, and it is less likely for the maleimides to crystallize with each other, that is, the solvent solubility of the maleimide is improved, which is a preferred embodiment.

In addition, as the compound represented by the general formula (5) (hereinafter, "compound (b)"), typically, in addition to aniline, for example, dimethylaniline, diethylaniline, diisopropylaniline, ethylmethylaniline, chloroaniline, dichloroaniline, toluidine, xylidine, phenylaniline, nitroaniline, aminophenol and cyclohexylaniline can be used. In addition, methoxyaniline, ethoxyaniline, phenoxyaniline, naphthoxyaniline, aminothiol, methylthioaniline, ethylthioaniline and phenylthioaniline can also be exemplified.

It should be noted that, when the maleimide group is directly bonded to the benzene ring as in the conventional maleimide (e.g., N-phenylmaleimide), the benzene ring and the 5-membered ring of maleimide are arranged in the same plane in a stable state, so it becomes easy to stack and exhibits high crystallinity. Therefore, it becomes the cause of poor solvent solubility. In contrast, in the case of the present invention, as the aforementioned compound (b), there is no particular limitation, and the compounds exemplified above can be used. In addition, for example, in the case of 2,6-dimethylaniline, when having a methyl group as a substituent, the benzene ring and the 5-membered ring of maleimide are in a distorted conformation due to the steric hindrance of the methyl group, and it becomes difficult to stack, so the crystallinity is reduced and the solvent solubility is improved, which is a preferred mode. Among them, if the steric hindrance is too large, there is also a concern that the reactivity is hindered during the synthesis of maleimide, so it is preferred to use, for example, a compound (b) having an alkyl group with 2 to 4 carbon atoms.

In the method for producing the intermediate amine compound represented by the general formula (6) used in the present invention, the aforementioned compound (a) and the aforementioned compound (b) are charged at a molar ratio of the aforementioned compound (b) to the aforementioned compound (a) (compound (b)/compound (a)) of preferably 0.1 to 2.0, more preferably 0.2 to 1.0, and reacted (first stage), and then the aforementioned compound (b) is further charged at a molar ratio of preferably 0.5 to 20.0, more preferably 0.7 to 5.0, to the aforementioned compound (a) charged previously, and reacted (second stage), thereby obtaining maleimide (A) having an indane skeleton. In addition, the two-step reaction both obtains a preferred result from the viewpoints of the completion of the reaction and the ease of handling. It should be noted that in the first stage of the reaction, the molar ratio of the compound (b) to the previously added compound (a) (compound (b)/compound (a)) is preferably set to 0.10 to 0.49, more preferably 0.15 to 0.40, and further preferably 0.20 to 0.39, so that the molecular weight distribution is wide, the content ratio of low molecular weight high melting point substances is reduced, and the proportion of high molecular weight components is increased. Therefore, it is preferred to obtain intermediate amine compounds and maleimides that are excellent in solvent solubility and can contribute to flexibility and brittleness resistance.

Examples of the acid catalyst used in the above-mentioned reaction include inorganic acids such as phosphoric acid, hydrochloric acid and sulfuric acid, organic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid and fluoromethanesulfonic acid, solid acids such as activated clay, acid clay, silica-alumina, zeolite and strongly acidic ion exchange resins, and heteropolyacid salts. Solid acids from which the catalyst can be easily removed by filtration after the reaction are also preferred from the viewpoint of handleability. When other acids are used, it is preferred to perform neutralization with an alkali and washing with water after the reaction.

The amount of the acid catalyst is 5 to 40 parts by weight relative to 100 parts by weight of the total amount of the compound (a) and the compound (b) initially added as raw materials, preferably 5 to 30 parts by weight from the perspective of handling and economic efficiency. The reaction temperature is usually in the range of 100 to 300° C., and is preferably 150 to 230° C. in order to suppress the formation of isomeric structures and avoid side reactions such as thermal decomposition.

As for the time of the above-mentioned reaction, if the time is short, the reaction will not be completely carried out. If the time is long, side reactions such as thermal decomposition reaction of the product may occur. Therefore, under the above-mentioned reaction temperature conditions, the total time is usually in the range of 2 to 48 hours, preferably 2 to 24 hours, more preferably 4 to 24 hours, and further preferably 4 to 12 hours. In order to reduce low molecular weight components and increase high molecular weight components, the total time is more preferably 8 to 12 hours.

In the above-mentioned method for producing the intermediate amine compound, aniline or its derivative also serves as a solvent, so it is not necessary to use other solvents, or a solvent can be used. For example, in the case of a reaction system that also has a dehydration reaction, specifically, when a compound having an α-hydroxypropyl group is used as a raw material for the reaction, the following method can be adopted: a solvent capable of azeotropic dehydration such as toluene, xylene, or chlorobenzene is used, and after the dehydration reaction is completed, the solvent is distilled off, and then the reaction is carried out within the above-mentioned reaction temperature range.

The maleimide (A) used in the present invention can be obtained as follows: the intermediate amine compound represented by the above general formula (6) obtained by the above method is put into a reactor, dissolved in a suitable solvent, and reacted in the presence of maleic anhydride and a catalyst. After the reaction, the unreacted maleic anhydride and other impurities are removed by washing with water, and the solvent is removed by decompression. In addition, a dehydrating agent can be used during the reaction.

The maleimide (A) used in the present invention includes a structure represented by the general formula (7) having a skeleton of the general formula (1) and an indane skeleton. When q is 3 or less and at least two of the ortho and para positions of the amino group are hydrogen atoms, a structure corresponding to the general formula (8), that is, a structure represented by the following general formula (9) may also be included as the structure represented by the general formula (1).

In the general formula (9), Ra, Rb, q, r and m have the same meanings as described above.

Examples of the organic solvent used in the maleimidation reaction for synthesizing the maleimide (A) include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, and acetophenone; aprotic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, acetonitrile, and sulfolane; cyclic ethers such as dioxane and tetrahydrofuran; esters such as ethyl acetate and butyl acetate; and aromatic solvents such as benzene, toluene, and xylene. These may be used alone or in combination.

In the maleimidation reaction, the intermediate amine compound and maleic anhydride are preferably mixed in a ratio of maleic anhydride to the amino group equivalent of the intermediate amine compound in the range of 1 to 1.5, more preferably 1.1 to 1.2, and the reaction is preferably carried out in an organic solvent in a mass ratio of 0.5 to 50, preferably 1 to 5, relative to the total amount of the intermediate amine compound and maleic anhydride.

Examples of the catalyst used in the maleimidization reaction include inorganic salts such as acetates, chlorides, bromides, sulfates, nitrates of nickel, cobalt, sodium, calcium, iron, lithium, manganese, etc., inorganic acids such as phosphoric acid, hydrochloric acid, and sulfuric acid, organic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid, solid acids such as activated clay, acid clay, silica-alumina, zeolite, and strongly acidic ion exchange resins, and heteropolyacid salts. Toluenesulfonic acid is particularly preferably used.

Examples of the dehydrating agent used in the maleimidation reaction include lower aliphatic carboxylic anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, oxides such as phosphorus pentoxide, calcium oxide, and barium oxide, inorganic acids such as sulfuric acid, and porous ceramics such as molecular sieves. Preferably, acetic anhydride can be used.

The amounts of the catalyst and the dehydrating agent used in the maleimidization reaction are not limited. Usually, the catalyst is used in an amount of 0.0001 to 1.0 mol, preferably 0.001 to 0.5 mol, more preferably 0.01 to 0.3 mol, and the dehydrating agent is used in an amount of 1 to 3 mol, preferably 1 to 1.5 mol, relative to 1 equivalent of the amino group of the intermediate amine compound.

As the reaction conditions of the maleimidation, the intermediate amine compound and maleic anhydride may be added, and the reaction may be carried out at a temperature range of 10 to 100° C., preferably 30 to 50° C., for 0.5 to 12 hours, preferably 1 to 8 hours, and then the catalyst may be added, and the reaction may be carried out at a temperature range of 90 to 130° C., preferably 105 to 120° C., for 2 to 24 hours, preferably 4 to 10 hours. In order to reduce low molecular weight components and increase high molecular weight components, the reaction may be carried out for 6 to 10 hours. In addition, after the reaction, unreacted maleic anhydride and other impurities may be removed by washing with water, and heat aging may be carried out, so that low molecular weight components may be reduced and high molecular weight components may be increased.

For the maleimide (A), the molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) calculated by gel permeation chromatography (GPC) is preferably in the range of 1.0 to 10.0, more preferably 1.1 to 9.0, further preferably 1.1 to 8.0, further preferably 1.2 to 5.0, further preferably 1.2 to 4.0, further preferably 1.3 to 3.8, particularly preferably 1.3 to 3.6, and most preferably 1.3 to 3.4, from the perspective of excellent low dielectric constant and low dielectric loss tangent. It should be noted that according to the GPC chart obtained by the above GPC measurement, when the molecular weight distribution is in a wide range and there are many high molecular weight components, the proportion of high molecular weight components contributing to flexibility becomes large, so compared with the cured product using the conventional maleimide, brittleness can be suppressed, and a cured product with excellent flexibility and softness can be obtained, which is a preferred embodiment.

<GPC measurement>

The molecular weight distribution (Mw/Mn) of the maleimide (A) was measured by gel permeation chromatography (GPC) under the following conditions.

Measuring device: HLC-8320GPC manufactured by Tosoh Corporation

Column: Guard column "HXL-L" manufactured by Tosoh Corporation + "TSK-GEL G2000HXL" manufactured by Tosoh Corporation + "TSK-GEL G2000HXL" manufactured by Tosoh Corporation + "TSK-GEL G3000HXL" manufactured by Tosoh Corporation + "TSK-GEL G4000HXL" manufactured by Tosoh Corporation

Detector: RI (differential refractometer)

Data processing: Tosoh Corporation's "GPC workstation EcoSEC-WorkStation"

Measurement conditions: Column temperature 40°C

Developing solvent: Tetrahydrofuran

Flow rate 1.0ml/min

Standard: According to the measurement manual of the aforementioned "GPC Workstation EcoSEC-WorkStation", the following monodisperse polystyrene having a known molecular weight was used.

(Using polystyrene)

"A-500" manufactured by Tosoh Corporation

"A-1000" manufactured by Tosoh Corporation

"A-2500" manufactured by Tosoh Corporation

"A-5000" manufactured by Tosoh Corporation

"F-1" manufactured by Tosoh Corporation

"F-2" manufactured by Tosoh Corporation

"F-4" manufactured by Tosoh Corporation

"F-10" manufactured by Tosoh Corporation

"F-20" manufactured by Tosoh Corporation

"F-40" manufactured by Tosoh Corporation

"F-80" manufactured by Tosoh Corporation

"F-128" manufactured by Tosoh Corporation

Sample: A solution of maleimide obtained in Synthesis Example at 1.0% by mass in tetrahydrofuran in terms of resin solid content was filtered through a microfilter (50 μl).

<Polyphenylene ether compound having reactive double bonds (B)>

The curable resin composition of the present invention is characterized in that, except containing the aforementioned maleimide (A) with indane skeleton, also containing the polyphenylene ether compound (B) with reactive double bond. The dielectric constant of the polyphenylene ether (PPE) contained in the structure of the aforementioned polyphenylene ether compound (B) with reactive double bond, dielectric loss tangent and other dielectric properties are excellent, therefore can prepare can obtain the curable resin composition of the cured product that also maintains sufficiently low dielectric constant and shows sufficiently low dielectric loss tangent in the high frequency band (high frequency region) such as MHz band to GHz band, therefore can be used as high frequency molding material, is useful. In addition, by with the aforementioned reaction of the maleimide (A) with indane skeleton, can be used as curing agent and play a role, three-dimensional crosslinking occurs, can obtain the cured product that heat resistance is also excellent, is preferred mode.

The polyphenylene ether compound (B) having a reactive double bond is not particularly limited as long as it has a reactive double bond in the molecule, and for example, has a structure represented by the following general formula (10) or (11).

In the general formulae (10) and (11), Rd can be independently exemplified by a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, a cycloalkyl group having 3 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a thioether group having 1 to 5 carbon atoms, an alkylcarbonyl group having 2 to 5 carbon atoms, an alkoxycarbonyl group having 2 to 5 carbon atoms, an alkylcarbonyloxy group having 2 to 5 carbon atoms, an alkylsulfonyl group having 1 to 5 carbon atoms, and the like. The general formulae (10) and (11) have a reactive double bond-containing group at the terminal structure thereof, and examples of the reactive double bond-containing group include an alkenyl group having 1 to 5 carbon atoms, a (meth)acryloyl group, a styryl group, a styrylmethyl group, and the like. In addition, s is an integer of 1 to 30, and t and u are also integers of 1 to 30.

The alkyl group having 1 to 5 carbon atoms is not particularly limited, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, and propyl.

The alkenyl group having 1 to 5 carbon atoms is not particularly limited, and examples thereof include vinyl, 1-propenyl, 1-butenyl, 1-pentenyl, and isopropenyl.

The cycloalkyl group having 3 to 5 carbon atoms is not particularly limited, and examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, and methylcyclobutyl.

The alkoxy group having 1 to 5 carbon atoms is not particularly limited, and examples thereof include methoxy, ethoxy, propoxy, isopropoxy, butoxy, and pentyloxy groups.

The thioether group having 1 to 5 carbon atoms is not particularly limited, and examples thereof include methylthio, ethylthio, propylthio, isopropylthio, butylthio, and pentylthio.

The alkylcarbonyl group having 2 to 5 carbon atoms is not particularly limited, and examples thereof include methylcarbonyl, ethylcarbonyl, propylcarbonyl, isopropylcarbonyl, and butylcarbonyl.

The alkoxycarbonyl group having 2 to 5 carbon atoms is not particularly limited, and examples thereof include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, and butoxycarbonyl.

The alkylcarbonyloxy group having 2 to 5 carbon atoms is not particularly limited, and examples thereof include methylcarbonyloxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, and butylcarbonyloxy groups.

The alkylsulfonyl group having 1 to 5 carbon atoms is not particularly limited, and examples thereof include methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, and pentylsulfonyl.

Among these, Rd is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a cycloalkyl group having 3 to 5 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, further preferably a hydrogen atom, a methyl group, or an ethyl group, and particularly preferably a hydrogen atom or a methyl group.

Examples of Y in the above (11) include a divalent aromatic group derived from an aromatic compound having two phenolic hydroxyl groups.

The aromatic compound having two phenolic hydroxyl groups is not particularly limited, and examples thereof include catechol, resorcinol, hydroquinone, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 4,4'-biphenol, bisphenol A, bisphenol B, bisphenol BP, bisphenol C, bisphenol F, tetramethylbisphenol A, etc. Among these, hydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 4,4'-biphenol, bisphenol A, bisphenol E, and bisphenol F are preferred, and 4,4'-biphenol, bisphenol A, and tetramethylbisphenol A are more preferred.

Since the two phenolic hydroxyl groups of the aromatic compound having two phenolic hydroxyl groups form a phenylene ether bond (two oxygen atoms bonded to Y), Y becomes a divalent aromatic group derived from the aromatic compound having two phenolic hydroxyl groups.

The weight average molecular weight (Mw) of the polyphenylene ether compound (B) having a reactive double bond is preferably 1000 to 5000, more preferably 1200 to 4000, and further preferably 1400 to 3000. When it is within the above range, a cured product having a balance of excellent dielectric properties and heat resistance can be obtained more reliably, which is a preferred embodiment. It should be noted that the weight average molecular weight (Mw) herein can be a value obtained by measuring according to a conventional molecular weight measurement method, and specifically, the value measured using GPC can be listed.

The curable resin composition of the present invention may also contain a curing agent other than the polyphenylene ether compound (B) having a reactive double bond within a range that does not impair the curing of the present invention. It should be noted that the polyphenylene ether compound (B) having a reactive double bond is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more, relative to 100% by mass of the total amount of the curing agent.

As the curing agent other than the polyphenylene ether compound (B) having a reactive double bond, for example, amine compounds, amide compounds, anhydride compounds, phenol compounds, cyanate compounds, compounds having unsaturated double bond-containing substituents, diene polymers, etc. These curing agents may be used alone or in combination of two or more.

Examples of the amine compound include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF ₃ -amine complex, and guanidine derivatives.

Examples of the amide compound include dicyandiamide and a polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine.

Examples of the acid anhydride compound include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

Examples of the phenolic compound include phenol novolac resins, cresol novolac resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resins, dicyclopentadiene phenol addition resins, phenol aralkyl resins (Xylock resins), polyphenol novolac resins synthesized from polyhydroxy compounds and formaldehyde represented by resorcinol novolac resins, naphthol aralkyl resins, trimethylolmethane resins, tetraphenol ethane resins, naphthol novolac resins, naphthol-phenol co-condensed novolac resins, and naphthol - cresol co-condensed phenol-formaldehyde varnish resin, biphenyl modified phenol-formaldehyde resin (a polyphenol compound formed by connecting phenol cores with dimethylene), biphenyl modified naphthol resin (a polyphenol compound formed by connecting phenol cores with dimethylene), aminotriazine modified phenol-formaldehyde resin (a polyphenol compound formed by connecting phenol cores with melamine, benzoguanamine, etc.), alkoxy-containing aromatic ring modified phenol-formaldehyde varnish resin (a polyphenol compound formed by connecting phenol cores and alkoxy-containing aromatic rings with formaldehyde) and other polyphenol compounds.

Examples of the cyanate compound include bisphenol A type cyanate resin, bisphenol F type cyanate resin, bisphenol E type cyanate resin, bisphenol S type cyanate resin, bisphenol sulfide type cyanate resin, phenylene ether type cyanate resin, naphthylene ether type cyanate resin, biphenyl type cyanate resin, tetramethylbiphenyl type cyanate resin, polyhydroxynaphthalene type cyanate resin, phenol novolac type cyanate resin, cresol novolac type cyanate resin, triphenylmethane type cyanate resin, tetraphenylethane type cyanate resin, dicyclopentadiene-phenol addition reaction type cyanate resin, phenol aralkyl type cyanate resin, naphthol novolac type cyanate resin, naphthol aralkyl type cyanate resin, naphthol-phenol co-decanoate type cyanate resin, naphthol-cresol co-decanoate type cyanate resin, aromatic hydrocarbon formaldehyde resin-modified phenolic resin type cyanate resin, biphenyl-modified novolac type cyanate resin, and anthracene type cyanate resin.

The aforementioned compound having an unsaturated double bond-containing substituent is not particularly limited, for example, as long as it has two or more unsaturated bond-containing substituents in the molecule, and examples of the aforementioned unsaturated bond-containing substituent include compounds having an allyl group, an isopropenyl group, a 1-propenyl group, an acryloyl group, a methacryloyl group, a styryl group, a styrylmethyl group, and the like.

As the diene polymer, for example, non-modified diene polymers that are not modified with polar groups can be cited. Here, the polar group is a functional group that affects dielectric properties, and for example, phenol groups, amino groups, epoxy groups, etc. can be cited. As the diene polymer, there is no particular limitation, and for example, 1,2-polybutadiene, 1,4-polybutadiene, etc. can be used.

As the diene polymer, a butadiene homopolymer in which 50% or more of the butadiene units in the polymer chain are 1,2-bonds, and a derivative thereof may be used.

<Preparation of Curable Resin Composition>

The curable resin composition of the present invention is characterized by containing: a maleimide (A) having an indane skeleton (hereinafter, sometimes referred to as "(A) component") and a polyphenylene ether compound (B) having a reactive double bond (hereinafter, sometimes referred to as "(B) component".). The aforementioned (B) component can be three-dimensionally crosslinked by reaction with the aforementioned (A) component, and a cured product having excellent dielectric properties and heat resistance can be obtained, which is a preferred embodiment.

As the blending ratio (parts by mass) of the aforementioned component (A) and the aforementioned component (B), the ratio of component (A) to component (B) is preferably 90:10 to 10:90, more preferably 80:20 to 20:80, further preferably 65:35 to 35:65, and particularly preferably 55:45 to 45:55. By adjusting the blending ratio to the aforementioned range, excellent heat resistance, low dielectric constant, and low dielectric loss tangent are achieved, and flexibility can be exhibited, which is preferred.

The curable resin composition of the present invention may contain alkenyl compounds, such as bismaleimides other than the maleimide (A), allyl ether compounds, allyl amine compounds, triallyl cyanurate, alkenyl phenol compounds, vinyl-containing polyolefin compounds, etc., within a range not impairing the purpose. In addition, other thermosetting resins, such as thermosetting polyimide resins, epoxy resins, phenolic resins, active ester resins, benzoxazine resins, cyanate resins, etc., may be appropriately blended according to the purpose.

In order to exert flame retardancy, the curable resin composition of the present invention may be compounded with a non-halogen flame retardant that does not substantially contain halogen atoms within a range that does not impair the purpose. Examples of the non-halogen flame retardant include phosphorus flame retardants, nitrogen flame retardants, silicone flame retardants, inorganic flame retardants, and organic metal salt flame retardants, which may be used alone or in combination.

Inorganic fillers can be mixed into the curable resin composition of the present invention as needed. As the aforementioned inorganic filler, for example, fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide, etc. can be cited. In particular, when the amount of the aforementioned inorganic filler is increased, fused silica is preferably used. The aforementioned fused silica can be used in any shape of crushed or spherical. In order to increase the amount of fused silica and suppress the rise in the melt viscosity of the molding material, it is preferred to mainly use spherical fused silica. Furthermore, in order to increase the amount of spherical silica, it is preferred to appropriately adjust the particle size distribution of spherical silica. For its filling rate, considering flame retardancy, it is preferably higher, and it is particularly preferred to be 20% by mass or more relative to the total amount of the curable resin composition. In addition, when the aforementioned curable resin composition is used for the purposes of the conductive paste described in detail below, conductive fillers such as silver powder and copper powder can be used.

The curable resin composition of the present invention may contain various compounding agents such as a curing accelerator, a silane coupling agent, a release agent, a pigment, and an emulsifier, as required.

<Solidified material>

The cured product of the present invention is preferably formed by subjecting the aforementioned curable resin composition to a curing reaction. The aforementioned curable resin composition can be obtained by uniformly mixing the aforementioned components, or can be easily made into a cured product by the same method as the conventionally known method. As the aforementioned cured product, a laminate, a cast molding, an adhesive layer, a coating, a film, and other shaped cured products can be listed.

As the aforementioned curing (thermosetting) reaction, it can also be easily carried out without a catalyst. In the case of wanting a quick reaction, the addition of a polymerization initiator such as an organic peroxide or an azo compound, a phosphine compound, or a basic catalyst such as a tertiary amine is effective. For example, benzoyl peroxide, diisopropylbenzene peroxide, azobisisobutyronitrile, triphenylphosphine, triethylamine, imidazoles, etc. are preferably added in an amount of 0.05 to 5% by mass of the entire curable resin composition.

<Prepreg>

The prepreg of the present invention preferably comprises a reinforcing substrate and a semi-cured product of the curable resin composition impregnated in the reinforcing substrate. As a method for preparing the prepreg, a known method can be used, wherein a resin varnish obtained by dissolving (diluting) the curable resin composition in an organic solvent is impregnated in the reinforcing substrate, and the reinforcing substrate impregnated with the resin varnish is heat-treated, thereby semi-curing (or uncuring) the curable resin composition to prepare the prepreg.

As the aforementioned organic solvent, for example, one species selected from toluene, xylene, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, methyl ethyl ketone (MEK), methyl isobutyl ketone, dioxane, tetrahydrofuran, etc. can be used alone or in the form of a mixed solvent of two or more species.

The reinforcing substrate for impregnating the resin varnish is a woven fabric, a nonwoven fabric, a mat, or a paper made of inorganic fibers such as glass fibers, polyester fibers, and polyamide fibers, or organic fibers, and these can be used alone or in combination.

The mass ratio of the curable resin composition to the reinforcing base material in the prepreg is not particularly limited, but is usually preferably prepared so that the curable resin composition (resin in the prepreg) is 20 to 60 mass %.

The heat treatment conditions for the prepreg can be appropriately selected depending on the type and amount of the organic solvent, catalyst, and various additives used, and are usually carried out at a temperature of 80 to 220° C. for 3 to 30 minutes.

<Heat-resistant materials and electronic materials>

The heat resistance and dielectric properties of the cured product obtained by the curable resin composition of the present invention are excellent, so it can be suitable for heat-resistant components and electronic components. Particularly, it can be suitable for circuit substrates, semiconductor sealing materials, semiconductor devices, laminated films, laminated substrates, adhesives, corrosion-resistant materials, etc. In addition, it can also be used for the matrix resin of fiber-reinforced resins, and is particularly suitable as a prepreg with high heat resistance. In addition, the aforementioned maleimide (A) with an indane skeleton contained in the aforementioned curable resin composition shows excellent solubility in various solvents, so it can be coated. The heat-resistant components and electronic components obtained in this way can be suitable for various purposes, such as industrial machinery parts, common machinery parts, parts of automobiles/railways/vehicles, space/aviation related parts, electronic/electrical parts, building materials, containers/packaging components, daily necessities, sports/leisure products, housing components for wind power generation, etc., but are not limited to these objects.

Hereinafter, typical products produced using the curable resin composition of the present invention will be described with reference to examples.

<Circuit Board>

In the present invention, the circuit board is preferably obtained by laminating the prepreg and copper foil and performing heat compression molding. Specifically, as a method for obtaining a circuit board from the curable resin composition of the present invention, the following method can be cited: laminating the prepreg by a conventional method, appropriately overlapping the copper foil, and performing heat compression molding at 170 to 300° C. for 10 minutes to 3 hours under a pressure of 1 to 10 MPa.

<Semiconductor sealing materials>

In the present invention, as a semiconductor sealing material, it is preferred to contain the aforementioned curable resin composition. Specifically, as a method for obtaining a semiconductor sealing material from the curable resin composition of the present invention, the following method can be cited: in the aforementioned curable resin composition, a curing accelerator as an arbitrary component and a compounding agent such as an inorganic filler are further melt-mixed until uniform using an extruder, a kneader, a roller, etc. as needed. At this time, as an inorganic filler, fused silica is usually used. When used as a high thermal conductivity semiconductor sealing material for power transistors and power ICs, crystalline silica, alumina, silicon nitride, etc. with higher thermal conductivity than fused silica can be used, and they can be highly filled. For its filling rate, it is preferred to use an inorganic filler in the range of 30 to 95 parts by mass relative to 100 parts by mass of the curable resin composition, wherein, in order to achieve flame retardancy, moisture resistance, improvement of solder cracking resistance, and reduction of linear expansion coefficient, more preferably 70 parts by mass or more, and further preferably 80 parts by mass or more.

<Semiconductor Device>

In the present invention, as a semiconductor device, it is preferred to include a cured product formed by heating and curing the semiconductor sealing material. Specifically, as a semiconductor encapsulation molding of a semiconductor device obtained from the curable resin composition of the present invention, the following method can be cited: the semiconductor sealing material is cast or molded using a transfer molding machine, an injection molding machine, etc., and then heated and cured at 50 to 250° C. for 2 to 10 hours.

<Layered Substrate>

As a method for obtaining a laminated substrate from the curable resin composition of the present invention, a method via steps 1 to 3 can be cited. In step 1, first, the aforementioned curable resin composition appropriately compounded with rubber, filler, etc. is applied to a circuit substrate formed with a circuit by a spray coating method, a curtain coating method, etc., and then cured. In step 2, after drilling a predetermined through-hole portion or the like on the circuit substrate coated with the curable resin composition as needed, it is treated with a roughening agent, and its surface is washed with hot water, thereby forming a concave-convex surface on the aforementioned substrate, and plated with a metal such as copper. In step 3, the operations of steps 1 to 2 are repeated in sequence as desired, and the resin insulating layer and the conductor layer of the predetermined circuit pattern are alternately laminated to form a laminated substrate. It should be noted that in the aforementioned step, it is preferable to perform the drilling of the through-hole portion after the formation of the outermost resin insulating layer. In addition, for the laminated substrate in the present invention, the resin-coated copper foil obtained by semi-curing the resin composition on the copper foil can be heated and pressed at 170 to 300° C. onto a wiring substrate having a circuit formed thereon, thereby forming a roughened surface and omitting the plating process to produce a laminated substrate.

<Laminated Film>

The laminated film of the present invention preferably contains the aforementioned curable resin composition. As a method for obtaining a laminated film from the curable resin composition of the present invention, for example, the following method can be cited: after applying the curable resin composition on a support film, it is dried to form a resin composition layer on the support film. When the curable resin composition of the present invention is used in a laminated film, it is important that the film softens under the lamination temperature conditions (usually 70°C to 140°C) of the vacuum lamination method, and exhibits fluidity (resin flow) that allows the resin to be filled in the vias or through holes of the circuit substrate while laminating the circuit substrate. In order to exhibit such characteristics, it is preferred to mix the aforementioned components. It should be noted that for the obtained laminated film and circuit substrate (copper-clad laminate, etc.), in order to exhibit the specified performance in any part without causing the phenomenon of locally displaying different characteristic values caused by phase separation, etc., uniformity of appearance is required.

Here, the through hole of the circuit board usually has a diameter of 0.1 to 0.5 mm and a depth of 0.1 to 1.2 mm, and the resin filling can usually be performed within this range. It should be noted that when laminating both sides of the circuit board, it is ideal to fill about 1/2 of the through hole.

As a specific method for producing the aforementioned laminated film, the following method can be listed: mixing an organic solvent to prepare a varnished resin composition, then coating the aforementioned varnished resin composition on the surface of a support film (Y), and then drying the organic solvent by heating or hot air blowing to form a resin composition layer (X).

As the organic solvent used here, for example, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate, carbitols such as cellosolve and butyl carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. are preferably used. In addition, it is preferably used in a ratio of 30 to 60% by mass of non-volatile components.

It should be noted that the thickness of the aforementioned resin composition layer (X) formed usually needs to be set to be greater than the thickness of the conductor layer. The thickness of the conductor layer possessed by the circuit substrate is usually in the range of 5 to 70 μm, so the thickness of the aforementioned resin composition layer (X) preferably has a thickness of 10 to 100 μm. It should be noted that the aforementioned resin composition layer (X) in the present invention can be protected by a protective film described later. By protecting with a protective film, it is possible to prevent dust and the like from adhering to the surface of the resin composition layer and prevent damage.

The aforementioned support film and protective film can include polyolefins such as polyethylene, polypropylene, polyvinyl chloride, polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, polycarbonate, polyimide, and further metal foils such as release paper, copper foil, and aluminum foil. It should be noted that the support film and protective film can be subjected to matte treatment, corona treatment, and demolding treatment. The thickness of the support film is not particularly limited, and is usually used in the range of 10 to 150 μm, preferably 25 to 50 μm. In addition, the thickness of the protective film is preferably set to 1 to 40 μm.

The support film (Y) is peeled off after being laminated on a circuit board or after forming an insulating layer by heat curing. When the support film (Y) is peeled off after the resin composition layer constituting the laminated film is heat cured, the adhesion of dust and the like during the curing process can be prevented. When peeling off after curing, the support film is usually subjected to a demolding treatment in advance.

It should be noted that a multilayer printed circuit board can be manufactured from the laminated film obtained as described above. For example, when the resin composition layer (X) is protected by a protective film, after peeling them off, the layer (X) of the resin composition is laminated on one or both sides of the circuit substrate in a manner of directly contacting the circuit substrate by, for example, vacuum lamination. The lamination method may be intermittent or continuous with a roller. In addition, as required, the laminated film and the circuit substrate may be heated (preheated) as required before lamination. As for the lamination conditions, the pressing temperature (lamination temperature) is preferably set to 70 to 140°C, and the pressing pressure is preferably set to 1 to 11 kgf/cm ² (9.8×10 ⁴ to 107.9×10 ⁴ N/m ² ), and the lamination is preferably performed under reduced pressure of 20 mmHg (26.7 hPa) or less.

<Conductive paste>

As a method of obtaining a conductive paste from the curable resin composition of the present invention, for example, there is a method of dispersing conductive particles in the composition. The conductive paste may be a circuit connection paste resin composition or an anisotropic conductive adhesive, depending on the type of conductive particles used.

Example

Next, the present invention will be specifically described by way of Examples and Comparative Examples. Hereinafter, "parts" and "%" are by mass unless otherwise specified. It should be noted that the softening point, amine equivalent, GPC, and FD-MS spectrum were measured and evaluated under the following conditions.

1) Softening point

Measurement method: The softening point (° C.) of the intermediate amine compound obtained in the synthesis example shown below was measured in accordance with JIS K7234 (ring and ball method).

2) Amine equivalent

The amine equivalent of the intermediate amine compound is measured by the following measurement method.

About 2.5 g of the intermediate amine compound as a sample, 7.5 g of pyridine, 2.5 g of acetic anhydride, and 7.5 g of triphenylphosphine were accurately weighed in a 500 mL stoppered Erlenmeyer flask, and then a condenser was installed and heated to reflux in an oil bath set at 120° C. for 150 minutes.

After cooling, 5.0 mL of distilled water, 100 mL of propylene glycol monomethyl ether, and 75 mL of tetrahydrofuran were added, and titrated using a 0.5 mol/L potassium hydroxide-ethanol solution by potentiometric titration. A blank test was performed and calibrated in the same manner.

Amine equivalent (g/eq.) = (S×2000)/(Blank-A)

S: Sample quantity (g)

A: Consumption of 0.5 mol/L potassium hydroxide-ethanol solution (mL)

Blank: Consumption of 0.5 mol/L potassium hydroxide-ethanol solution in the blank test (mL)

3) GPC determination

The following measuring apparatus and measuring conditions were used to measure and obtain the GPC graphs of the maleimide obtained in the synthesis examples shown below (Figures 1 to 9). According to the results of the aforementioned GPC graphs, based on the number average molecular weight (Mn), the molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) and the average number of repeating units "n" contributing to the indane skeleton in the maleimide were measured/calculated. Specifically, for compounds with n=0 to 4, the theoretical molecular weight and each of the measured molecular weights in GPC are plotted on the scatter plot, an approximate straight line is drawn, and the number average molecular weight (Mn) is obtained from the points represented by the measured value Mn (1) on the straight line, and n is calculated.

Measuring device: HLC-8320GPC manufactured by Tosoh Corporation

Column: Guard column "HXL-L" manufactured by Tosoh Corporation + "TSK-GEL G2000HXL" manufactured by Tosoh Corporation + "TSK-GEL G2000HXL" manufactured by Tosoh Corporation + "TSK-GEL G3000HXL" manufactured by Tosoh Corporation + "TSK-GEL G4000HXL" manufactured by Tosoh Corporation

Detector: RI (differential refractometer)

Data processing: Tosoh Corporation's "GPC Workstation EcoSEC-WorkStation"

Measurement conditions: Column temperature 40°C

Developing solvent: Tetrahydrofuran

Flow rate 1.0ml/min

Standard: According to the measurement manual of the aforementioned "GPC Workstation EcoSEC-WorkStation", the following monodisperse polystyrene having a known molecular weight was used.

(Using polystyrene)

"A-500" manufactured by Tosoh Corporation

"A-1000" manufactured by Tosoh Corporation

"A-2500" manufactured by Tosoh Corporation

"A-5000" manufactured by Tosoh Corporation

"F-1" manufactured by Tosoh Corporation

"F-2" manufactured by Tosoh Corporation

"F-4" manufactured by Tosoh Corporation

"F-10" manufactured by Tosoh Corporation

"F-20" manufactured by Tosoh Corporation

"F-40" manufactured by Tosoh Corporation

"F-80" manufactured by Tosoh Corporation

"F-128" manufactured by Tosoh Corporation

Sample: A solution of maleimide obtained in Synthesis Example at 1.0% by mass in tetrahydrofuran in terms of resin solid content was filtered through a microfilter (50 μl).

4) FD-MS spectrum

The FD-MS spectrum was measured using the following measuring apparatus and measuring conditions.

Measurement device: JMS-T100GC AccuTOF

Measurement conditions

Measurement range: m/z = 4.00 to 2000.00

Change rate: 51.2mA/minute

Final current value: 45mA

Cathode voltage: -10kV

Recording interval: 0.07 seconds

[Synthesis Example 1] Synthesis of Maleimide Compound A-1

(1) Synthesis of intermediate amine compounds

In a 1L flask equipped with a thermometer, a condenser, a Dean-Stark trap, and a stirrer, 48.5 g (0.4 mol) of 2,6-dimethylaniline, 272.0 g (1.4 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 280 g of xylene, and 70 g of activated clay were added, and heated to 120°C while stirring. The distilled water was removed by a Dean-Stark trap, and the temperature was raised to 210°C, and the reaction was carried out for 3 hours. Thereafter, the mixture was cooled to 140°C, 145.4 g (1.2 mol) of 2,6-dimethylaniline was added, and the temperature was raised to 220°C, and the reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 100°C in air, diluted with 300 g of toluene, the activated clay was removed by filtration, and low molecular weight substances such as the solvent and unreacted products were distilled off under reduced pressure, thereby obtaining 364.1 g of an intermediate amine compound represented by the following general formula (A-1). The amine equivalent is 298 and the softening point is 70°C.

(2) Maleimidation

In a 2L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 131.8 g (1.3 mol) of maleic anhydride and 700 g of toluene were added and stirred at room temperature, and then a mixed solution of 364.1 g of the reactant (A-1) and 175 g of DMF was added dropwise over 1 hour.

After the addition was completed, the reaction was further carried out at room temperature for 2 hours. 37.1 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, the water and toluene under reflux were cooled/separated, and then only toluene was returned to the system and dehydration reaction was carried out for 8 hours. After air cooling to room temperature, it was concentrated under reduced pressure, the brown solution was dissolved in 600 g of ethyl acetate, washed 3 times with 150 g of ion exchange water and 150 g of 2% sodium bicarbonate aqueous solution 3 times, sodium sulfate was added for drying, and then concentrated under reduced pressure, the obtained reactant was vacuum dried at 80 ° C for 4 hours to obtain 413.0 g of a product containing maleimide compound A-1. In the FD-MS spectrum of the maleimide compound A-1, peaks of M+=560, 718, and 876 were confirmed, and each peak corresponds to the case where n is 0, 1, and 2. The value of the repeating unit number n (based on the number average molecular weight) in the indane skeleton portion of the maleimide A-1 was determined by GPC. The GPC chart is shown in FIG1 , where n=1.47 and the molecular weight distribution (Mw/Mn)=1.81.

[Synthesis Example 2] Synthesis of maleimide compound A-2

(1) Synthesis of intermediate amine compounds

In a 1L flask equipped with a thermometer, a condenser, a Dean-Stark trap, and a stirrer, 48.5 g (0.4 mol) of 2,6-dimethylaniline, 233.2 g (1.2 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 230 g of xylene, and 66 g of activated clay were added, and heated to 120°C while stirring. The distilled water was removed using a Dean-Stark trap, and the temperature was raised to 210°C, and the reaction was carried out for 3 hours. Thereafter, the mixture was cooled to 140°C, 145.4 g (1.2 mol) of 2,6-dimethylaniline was added, and the temperature was raised to 220°C, and the reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 100°C in air, diluted with 300 g of toluene, the activated clay was removed by filtration, and low molecular weight substances such as the solvent and unreacted products were distilled off under reduced pressure, thereby obtaining 278.4 g of an intermediate amine compound represented by the following general formula (A-2). The amine equivalent is 294 and the softening point is 65°C.

(2) Maleimidation

In a 2L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 107.9 g (1.1 mol) of maleic anhydride and 600 g of toluene were added and stirred at room temperature, and then a mixed solution of 278.4 g of the reactant (A-2) and 150 g of DMF was added dropwise over 1 hour.

After the addition was completed, the reaction was further carried out at room temperature for 2 hours. 27.0 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, the water and toluene under reflux were cooled/separated, and then only toluene was returned to the system and dehydrated for 8 hours. After the air was cooled to room temperature, it was concentrated under reduced pressure, the brown solution was dissolved in 500 g of ethyl acetate, washed 3 times with 120 g of ion exchange water and 3 times with 120 g of 2% sodium bicarbonate aqueous solution, sodium sulfate was added for drying, and then concentrated under reduced pressure, the obtained reactant was vacuum dried at 80 ° C for 4 hours to obtain 336.8 g of a product containing maleimide compound A-2. In the FD-MS spectrum of the maleimide compound A-2, peaks of M+=560, 718, and 876 were confirmed, which corresponded to the cases where n was 0, 1, and 2, respectively. The value of the number of repeating units n in the indane skeleton part of the maleimide A-2 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG2 , where n=1.25 and the molecular weight distribution (Mw/Mn)=3.29.

[Synthesis Example 3] Synthesis of maleimide compound A-3

(1) Synthesis of intermediate amine compounds

In a 2L flask equipped with a thermometer, a condenser, a Dean-Stark trap, and a stirrer, 48.5 g (0.4 mol) of 2,6-dimethylaniline, 388.6 g (2.0 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 350 g of xylene, and 123 g of activated clay were added, and heated to 120°C while stirring. The distilled water was removed using a Dean-Stark trap, and the temperature was raised to 210°C, and the reaction was carried out for 3 hours. Thereafter, the mixture was cooled to 140°C, 145.4 g (1.2 mol) of 2,6-dimethylaniline was added, and the temperature was raised to 220°C, and the reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 100°C in air, diluted with 500 g of toluene, the activated clay was removed by filtration, and low molecular weight substances such as the solvent and unreacted products were distilled off under reduced pressure, thereby obtaining 402.1 g of an intermediate amine compound represented by the following general formula (A-3). The amine equivalent is 306 and the softening point is 65°C.

(2) Maleimidation

In a 2L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 152.1 g (1.5 mol) of maleic anhydride and 700 g of toluene were added and stirred at room temperature, and then a mixed solution of 402.1 g of the reactant (A-3) and 200 g of DMF was added dropwise over 1 hour.

After the addition was completed, the reaction was further carried out at room temperature for 2 hours. 37.5 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, the water and toluene under reflux were cooled/separated, and then only toluene was returned to the system and dehydrated for 8 hours. After air cooling to room temperature, it was concentrated under reduced pressure, the brown solution was dissolved in 800 g of ethyl acetate, washed 3 times with 200 g of ion exchange water and 3 times with 200 g of 2% sodium bicarbonate aqueous solution, sodium sulfate was added for drying, and then concentrated under reduced pressure, the obtained reactant was vacuum dried at 80 ° C for 4 hours to obtain 486.9 g of a product containing maleimide compound A-3. In the FD-MS spectrum of the maleimide compound A-3, peaks of M+=560, 718, and 876 were confirmed, which corresponded to the cases where n was 0, 1, and 2, respectively. The value of the number of repeating units n in the indane skeleton part of the maleimide A-3 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG3 , where n=1.96 and the molecular weight distribution (Mw/Mn)=1.52.

[Synthesis Example 4] Synthesis of maleimide compound A-4

(1) Synthesis of intermediate amine compounds

In a 2L flask equipped with a thermometer, a condenser, a Dean-Stark trap, and a stirrer, 59.7 g (0.4 mol) of 2,6-diethylaniline, 272.0 g (1.4 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 350 g of xylene, and 94 g of activated clay were added, and heated to 120°C while stirring. The distilled water was removed using a Dean-Stark trap, and the temperature was raised to 210°C, and the reaction was carried out for 3 hours. Thereafter, the mixture was cooled to 140°C, 179.1 g (1.2 mol) of 2,6-diethylaniline was added, and the temperature was raised to 220°C, and the reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 100°C in air, diluted with 500 g of toluene, the activated clay was removed by filtration, and low molecular weight substances such as the solvent and unreacted products were distilled off under reduced pressure, thereby obtaining 342.1 g of an intermediate amine compound represented by the following general formula (A-4). The amine equivalent is 364 and the softening point is 47°C.

(2) Maleimidation

In a 2L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 107.9 g (1.1 mol) of maleic anhydride and 600 g of toluene were added and stirred at room temperature, and then a mixed solution of 342.1 g of the reactant (A-4) and 180 g of DMF was added dropwise over 1 hour.

After the addition was completed, the reaction was further carried out at room temperature for 2 hours. 26.8 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, the water and toluene under reflux were cooled/separated, and then only toluene was returned to the system and dehydrated for 8 hours. After air cooling to room temperature, it was concentrated under reduced pressure, the brown solution was dissolved in 500 g of ethyl acetate, washed 3 times with 200 g of ion exchange water and 3 times with 200 g of 2% sodium bicarbonate aqueous solution, sodium sulfate was added for drying, and then concentrated under reduced pressure, the obtained reactant was vacuum dried at 80 ° C for 4 hours to obtain 388.1 g of a product containing maleimide compound A-4. In the FD-MS spectrum of the maleimide compound A-4, peaks of M+=616, 774, and 932 were confirmed, which corresponded to the cases where n was 0, 1, and 2, respectively. The value of the number of repeating units n in the indane skeleton part of the maleimide A-4 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG4 , where n=1.64 and the molecular weight distribution (Mw/Mn)=1.40.

[Synthesis Example 5] Synthesis of maleimide compound A-5

(1) Synthesis of intermediate amine compounds

In a 1L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 70.9g (0.4mol) of 2,6-diisopropylaniline, 272.0g (1.4mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 350g of xylene, and 97g of activated clay were added, and heated to 120°C while stirring. The distilled water was removed with a Dean-Stark trap, and the temperature was raised to 210°C, and the reaction was carried out for 3 hours. After that, the mixture was cooled to 140°C, 212.7g (1.2mol) of 2,6-diisopropylaniline was added, and the temperature was raised to 220°C, and the reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 100°C in air, diluted with 500 g of toluene, the activated clay was removed by filtration, and low molecular weight substances such as the solvent and unreacted products were distilled off under reduced pressure to obtain 317.5 g of an intermediate amine compound represented by the following general formula (A-5). The amine equivalent was 366 and the softening point was 55°C.

(2) Maleimidation

In a 2L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 107.9 g (1.1 mol) of maleic anhydride and 600 g of toluene were added and stirred at room temperature, and then a mixed solution of 317.5 g of the reactant (A-5) and 175 g of DMF was added dropwise over 1 hour.

After the addition was completed, the reaction was further carried out at room temperature for 2 hours. 24.8 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, the water and toluene azeotroped under reflux were cooled/separated, and then only toluene was returned to the system and dehydrated for 8 hours. After air cooling to room temperature, it was concentrated under reduced pressure, the brown solution was dissolved in 600 g of ethyl acetate, washed 3 times with 200 g of ion exchange water and 3 times with 200 g of 2% sodium bicarbonate aqueous solution, sodium sulfate was added for drying, and then concentrated under reduced pressure, the obtained reactant was vacuum dried at 80 ° C for 4 hours to obtain 355.9 g of a product containing maleimide compound A-5. In the FD-MS spectrum of the maleimide compound A-5, peaks of M+=672, 830, and 988 were confirmed, which corresponded to the cases where n was 0, 1, and 2, respectively. The value of the number of repeating units n in the indane skeleton part of the maleimide A-5 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG5 , where n=1.56 and the molecular weight distribution (Mw/Mn)=1.24.

[Synthesis Example 6] Synthesis of maleimide compound A-8

(1) Synthesis of intermediate amine compounds

In the above-mentioned synthesis method of the intermediate amine compound A-1, the reaction time at 210°C was changed to 6 hours, and the reaction time at 220°C was changed to 3 hours. The same operation was performed to obtain 345.2 g of the intermediate amine compound represented by the following general formula (A-8). The amine equivalent was 348 and the softening point was 71°C.

(2) Maleimidation

According to the synthesis method of the maleimide compound A-1, the intermediate is replaced by A-8, and the operation is performed in the same manner to obtain 407.6 g of a product containing the maleimide compound A-8. In the FD-MS spectrum of the maleimide compound A-8, peaks of M+=560, 718, and 876 are confirmed, and each peak corresponds to the case where n is 0, 1, and 2. It should be noted that the value of the number of repeating units n in the indane skeleton part of the maleimide A-8 (based on the number average molecular weight) is obtained by GPC, and the GPC diagram thereof is shown in Figure 6, n=2.59, and the molecular weight distribution (Mw/Mn)=1.49.

[Synthesis Example 7] Synthesis of maleimide compound A-9

In the synthesis method of the intermediate amine compound A-1, the reaction time at 210°C was changed to 6 hours, and the reaction time at 220°C was changed to 3 hours. The same operation was performed, and for the synthesized intermediate amine compound (amine equivalent of 347, softening point of 71°C), the dehydration reaction under reflux in the maleimide reaction was set to 10 hours. Except for this, the same conditions as the synthesis method of the maleimide compound A-1 were used to obtain 415.6 g of a product containing maleimide compound A-9. In the FD-MS spectrum of the maleimide compound A-9, peaks of M+=560, 718, and 876 were confirmed, and each peak corresponds to the case where n is 0, 1, and 2. The value of the number of repeating units n in the indane skeleton part of the maleimide A-9 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG7 , where n=2.91 and the molecular weight distribution (Mw/Mn)=1.64.

[Synthesis Example 8] Synthesis of maleimide compound A-10

In the synthesis method of the intermediate amine compound A-1, the reaction time at 210° C. was changed to 9 hours, and the reaction time at 220° C. was changed to 3 hours. The same operation was performed, and for the synthesized intermediate amine compound (amine equivalent of 342, softening point of 69° C.), the dehydration reaction under reflux in the maleimide reaction was set to 10 hours. The same conditions as the synthesis method of the maleimide compound A-1 were used to obtain 398.7 g of a product containing the maleimide compound A-10. In the FD-MS spectrum of the maleimide compound A-10, peaks of M+=560, 718, and 876 were confirmed, and each peak corresponds to the case where n is 0, 1, and 2. The value of the number of repeating units n in the indane skeleton part of the maleimide A-10 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG8 , where n=3.68 and the molecular weight distribution (Mw/Mn)=2.09.

[Synthesis Example 9] Synthesis of Maleimide Compound A-11

In the synthesis method of the intermediate amine compound A-1, the reaction time at 210° C. was changed to 9 hours, and the reaction time at 220° C. was changed to 3 hours. The same operation was performed, and the dehydration reaction under reflux in the maleimide reaction of the synthesized intermediate amine compound (amine equivalent of 347, softening point of 70° C.) was set to 12 hours. The same conditions as the synthesis method of the maleimide compound A-1 were used to obtain 422.7 g of a product containing the maleimide compound A-11. In the FD-MS spectrum of the maleimide compound A-11, peaks of M+=560, 718, and 876 were confirmed, and each peak corresponds to the case where n is 0, 1, and 2. The value of the number of repeating units n in the indane skeleton part of the maleimide A-11 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG9 , where n=4.29 and the molecular weight distribution (Mw/Mn)=3.02.

[Examples 1 to 9 and Comparative Example 1]

<Solvent Solubility of Maleimide>

The solubility of the maleimides (A-1) to (A-5), (A-8) to (A-11) obtained in Synthesis Examples 1 to 9, and the commercially available maleimide (A-6) (4,4'-diphenylmethanebismaleimide, "BMI-1000" manufactured by Yamato Chemical Industries, Ltd.) for comparison in toluene and methyl ethyl ketone (MEK) was evaluated. The evaluation results are shown in Table 1.

As a method for evaluating solvent solubility, toluene solutions and methyl ethyl ketone (MEK) solutions were prepared using the maleimides obtained in the above Synthesis Examples and Comparative Examples so that the nonvolatile content was 10, 20, 30, 40, 50, 60, and 70% by mass.

Specifically, the vials containing the maleimides obtained in the above-mentioned synthesis examples and comparative examples were placed at room temperature (25° C.) for 60 days, and the situation that each non-volatile component was uniformly dissolved in each solution (no insoluble matter) was evaluated as 0, and the situation that was not dissolved (with insoluble matter) was evaluated as × (visual). It should be noted that if the non-volatile component is 20% by mass or more and can be dissolved in a solvent, it is practically preferred.

[Examples 10 to 18 and Comparative Example 2]

<Preparation of Curable Resin Composition>

The maleimides (A-1) to (A-5), (A-8) to (A-11) obtained in Synthesis Examples 1 to 9, the comparative maleimide (A-6) (4,4'-diphenylmethanebismaleimide, "BMI-1000" manufactured by Yamato Chemical Industry Co., Ltd.), and the polyphenylene ether compound (B-1) having a reactive double bond ("SA-9000", manufactured by SABIC, Mw: 1700) were blended in the proportions shown in Table 2 to prepare a curable resin composition.

<Preparation of Cured Product (Molded Product)>

The following conditions were applied to the curable resin composition to prepare a cured product (molded product).

Curing conditions: After heating at 200°C for 2 hours, heat curing was further performed at 250°C for 2 hours.

Thickness of the cured product (molded product) after molding: 2.4 mm

The obtained cured product was evaluated for various physical properties and characteristics by the following methods. The evaluation results are shown in Table 3.

[Examples 19 to 24 and Comparative Examples 3 to 4]

<Preparation of Curable Resin Composition>

The maleimides (A-1), (A-8) to (A-11) obtained in Synthesis Examples 1 and 6 to 9, the comparative maleimide (A-7) (3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, "BMI-5100" manufactured by Yamato Chemical Industry Co., Ltd.), the polyphenylene ether compound having a reactive double bond (B-1) ("SA-9000", manufactured by SABIC, Mw: 1700), the vinylbenzyl polyphenylene ether compound (B-2), and methyl ethyl ketone (MEK) were mixed in the proportions shown in Table 4 to prepare a curable resin composition.

The compound (B-2) was synthesized according to Example 1 of Japanese Patent No. 6147538.

<Varnish solubility and film appearance uniformity>

In each curable resin composition of Examples 19 to 24 and Comparative Examples 3 to 4, whether it is uniformly dissolved (confirmation of varnish solubility) was visually confirmed. The case of uniform dissolution was evaluated as 0, and the case of non-uniform dissolution or complete insolubility was evaluated as × (for example, the case of the presence of insoluble matter, etc.).

In addition, each curable resin composition 5g is coated into a demoulding PET film (thickness after drying: 295μm), dried (heated) for 1 hour at 80°C, and then dried (heated) for 1 hour at 120°C to make a film molding, and the appearance of the obtained film molding is visually confirmed. The uniform appearance of the film is evaluated as 0, and the uneven appearance of the film is evaluated as × (for example, when turbidity, insoluble matter, etc. can be confirmed). The evaluation results are shown in Table 4.

<Glass transition temperature (Tg)>

The cured product with a thickness of 2.4 mm was cut into a size of 5 mm in width and 54 mm in length, and used as a test piece. The test piece was evaluated using a viscoelasticity measuring device (DMA: solid viscoelasticity measuring device "DMS6100" manufactured by Hitachi High-Tech Science Corporation, deformation mode: fixed bending at both ends, measurement mode: sinusoidal oscillation, frequency 1 Hz, heating rate 3°C/min), and the temperature with the largest change in elastic modulus (the largest rate of change in tanδ) was set as the glass transition temperature Tg (°C). It should be noted that from the viewpoint of heat resistance, the glass transition temperature Tg is preferably above 250°C (high Tg), and more preferably above 260°C.

<Resistance to thermal decomposition>

The cured product with a thickness of 2.4 mm was cut into smaller pieces and measured in a nitrogen atmosphere using a thermogravimetric analyzer (thermogravimetric analyzer "TGA/DSC1" manufactured by METTLER TOREDO) with a heating rate of 5°C/min. The temperature at which the weight was reduced by 5% was set as the thermal decomposition temperature (Td5) (°C) for evaluation.

<Thermal Expansion>

The cured product with a thickness of 2.4 mm was cut into a size of 5 mm in width and 5 mm in length, and used as a test piece. The thermal expansion coefficient CTE (ppm) in the range of 40 to 60° C. was measured using a thermal analyzer (“TMA/SS6100” manufactured by SII NanoTechnology Inc., with a heating rate of 3° C./min). It should be noted that, from the viewpoint of heat resistance and prevention of warping, the thermal expansion coefficient is preferably 60 ppm or less, and more preferably 55 ppm or less.

<Dielectric properties>

According to JIS-C-6481, the dielectric constant and dielectric loss tangent at 1 GHz of the test piece after being stored in a room at 23 ° C and 50% humidity for 24 hours after absolute drying were measured using a network analyzer "E8362C" manufactured by Agilent Technologies Co., Ltd. by a cavity resonant cavity method. It should be noted that, as the dielectric constant and dielectric loss tangent, from the viewpoint of reducing the transmission loss as an electronic material, the dielectric constant is preferably 2.60 or less, more preferably 2.55 or less. In addition, the dielectric loss tangent is preferably 0.0020 or less, more preferably 0.0015 or less.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

According to the evaluation results in Table 1, it can be confirmed that in Examples 1 to 9, since maleimide having an indane skeleton is used, when preparing a toluene solution, the non-volatile component can be dissolved even if it is 20% by mass, and when preparing a MEK solution, the non-volatile component can be dissolved even if it is 50% by mass, and the solvent solubility is excellent. On the other hand, it was confirmed that the commercially available maleimide used in Comparative Example 1 does not have an indane skeleton in its structure and has poor solvent solubility.

According to the evaluation results of Table 3 above, it can be confirmed that in Examples 10 to 18, in addition to using maleimide having an indane skeleton, a polyphenylene ether compound (B) having a reactive double bond containing polyphenylene ether that also contributes to dielectric properties is used in the structure, so that the glass transition temperature and the heat decomposition temperature are high, and the thermal expansion coefficient can be suppressed to a small value, so the heat resistance and heat decomposition resistance are excellent. It can also be confirmed that the dielectric constant and the dielectric loss tangent are also suppressed to be low, so the dielectric properties are excellent. On the other hand, for Comparative Example 2, it can be confirmed that the glass transition temperature and the heat decomposition temperature are low and the thermal expansion coefficient is high relative to the embodiment, so the heat resistance and heat decomposition resistance are poor, and it can also be confirmed that the dielectric constant and the dielectric loss tangent cannot be suppressed to be lower than the embodiment, and the dielectric properties are poor.

According to the evaluation results in Table 4, it can be confirmed that in Examples 19 to 24, the curable resin composition solution (varnish) containing maleimide having an indane skeleton is uniformly dissolved, and the appearance of the film obtained by applying and drying the curable resin composition solution (varnish) is uniform, and the laminated film, which is particularly required to have uniform appearance of the obtained film, can also be used for applications such as circuit substrates (copper-clad laminates, etc.). On the other hand, it was confirmed that in Comparative Examples 3 to 4, commercially available maleimide without an indane skeleton was used, so the appearance of the film was uneven, and it was difficult to use it for applications such as laminated films and circuit substrates (copper-clad laminates, etc.).

Industrial Applicability

The cured product of the curable resin composition of the present invention has excellent heat resistance and dielectric properties, and therefore can be suitably used in heat-resistant components, electronic components, and in particular can be suitably used in semiconductor sealing materials, circuit substrates, laminated films, laminated substrates, adhesives, and corrosion-resistant materials. In addition, it can also be suitably used in the matrix resin of fiber-reinforced resins, and is suitable as a highly heat-resistant prepreg.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a GPC chart of the maleimide compound (A-1) obtained in Synthesis Example 1.

FIG. 2 is a GPC chart of the maleimide compound (A-2) obtained in Synthesis Example 2.

FIG. 3 is a GPC chart of the maleimide compound (A-3) obtained in Synthesis Example 3.

FIG. 4 is a GPC chart of the maleimide compound (A-4) obtained in Synthesis Example 4.

FIG. 5 is a GPC chart of the maleimide compound (A-5) obtained in Synthesis Example 5.

FIG6 is a GPC chart of the maleimide compound (A-8) obtained in Synthesis Example 6.

FIG. 7 is a GPC chart of the maleimide compound (A-9) obtained in Synthesis Example 7.

FIG. 8 is a GPC chart of the maleimide compound (A-10) obtained in Synthesis Example 8.

FIG. 9 is a GPC chart of the maleimide compound (A-11) obtained in Synthesis Example 9.

Claims (7)

1. A curable resin composition characterized by comprising: a maleimide (A) having an indane skeleton, and a polyphenylene ether compound (B) having a reactive double bond,

The maleimide (A) is represented by the following general formula (1),

In the formula (1), ra independently represents an alkyl group, an alkoxy group or an alkylthio group having 1 to 10 carbon atoms, an aryl group, an aryloxy group or an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group or a mercapto group, q represents an integer of 0 to 4, ra is optionally the same or different in the same ring when q is 2 to 4, rb independently represents an alkyl group, an alkoxy group or an alkylthio group having 1 to 10 carbon atoms, an aryl group, an aryloxy group or an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group or a mercapto group, r represents an integer of 0 to 3, r is optionally the same or different in the same ring when r is 2 to 3, and n represents an average repeating unit number of 0.5 to 20.

2. A cured product obtained by curing the curable resin composition according to claim 1.

3. A prepreg comprising a reinforcing substrate and a prepreg impregnated with the curable resin composition according to claim 1.

4. A circuit board obtained by laminating the prepreg according to claim 3 and a copper foil and performing thermocompression bonding molding.

5. A laminated film comprising the curable resin composition according to claim 1.

6. A semiconductor sealing material comprising the curable resin composition according to claim 1.

7. A semiconductor device comprising a cured product obtained by heat curing the semiconductor sealing material according to claim 6.