JP7116934B2 - Curable resin composition - Google Patents

Description

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.

As a material for circuit boards for electronic devices, a prepreg obtained by impregnating a glass cloth with a thermosetting resin such as an epoxy resin or a BT (bismaleimide-triazine) resin and drying by heating, or by heating and curing the prepreg. Laminated plates and multi-layered plates obtained by combining the laminated plate and the prepreg and heat-cured are widely used. In particular, semiconductor package substrates are becoming thinner, and warping of package substrates during mounting poses a problem.

In recent years, the speed and frequency of signals have increased, and it has become necessary to provide a thermosetting resin composition that provides a cured product exhibiting a sufficiently low dielectric loss tangent while maintaining a sufficiently low dielectric constant under these circumstances. Desired.

In particular, in recent years, various electronic materials, especially advanced materials, have been required to have further improved properties such as heat resistance and dielectric properties, and materials and compositions having these properties.

In response to these requirements, maleimide resins are attracting attention as a material that has both heat resistance and a low dielectric constant and low dielectric loss tangent. However, although conventional maleimide resins exhibit high heat resistance, their dielectric constant and dielectric loss tangent values have not reached the levels required for advanced material applications. There is a strong demand for the development of a resin that exhibits a lower dielectric constant and a lower dielectric loss tangent while maintaining heat resistance and is also excellent in solvent solubility.

Under such circumstances, phenol novolac type cyanate ester resin, bisphenol A cyanate ester resin, and halogen-free epoxy resin are blended as cyanate ester-based materials with high dielectric properties and heat resistance. is known (see Patent Document 1).

However, although the resin composition described in Patent Document 1 improves the heat resistance and dielectric properties of the cured product to some extent, the heat resistance still falls short of the levels required in recent years.

Japanese Patent Application Laid-Open No. 2004-182850

Therefore, the problem to be solved by the present invention is a curable resin composition having excellent heat resistance and dielectric properties in its cured product, a cured product thereof, a prepreg, a circuit board, and a build having these properties. An object of the present invention is to provide an up film, a semiconductor sealing material, and a semiconductor device.

Therefore, the present inventors have made intensive studies in order to solve the above problems, and as a result, a curable resin composition containing a maleimide (A) having an indane skeleton and a cyanate ester compound (B) is a cured product thereof. In the above, the present inventors have completed the present invention by finding that it is possible to have both a low dielectric constant and a low dielectric loss tangent and excellent heat resistance.

That is, the present invention relates to a curable resin composition characterized by containing a maleimide (A) having an indane skeleton and a cyanate ester compound (B).

（式（１）中、Ｒａは、それぞれ独立に、炭素数１～１０のアルキル基、アルキルオキシ基もしくはアルキルチオ基、炭素数６～１０のアリール基、アリールオキシ基もしくはアリールチオ基、炭素数３～１０のシクロアルキル基、ハロゲン原子、ニトロ基、水酸基またはメルカプト基を表し、ｑは０～４の整数値を示す。ｑが２～４の場合、Ｒａは同一環内で同じであってもよいし異なっていてもよい。Ｒｂはそれぞれ独立に、炭素数１～１０のアルキル基、アルキルオキシ基もしくはアルキルチオ基、炭素数６～１０のアリール基、アリールオキシ基もしくはアリールチオ基、炭素数３～１０のシクロアルキル基、ハロゲン原子、水酸基またはメルカプト基を表し、ｒは０～３の整数値を示す。ｒが２～３の場合、Ｒｂは同一環内で同じであってもよいし異なっていてもよい。ｎは平均繰り返し単位数であり、０．５～２０の数値を示す。）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 is each independently an alkyl group, alkyloxy group or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group or arylthio group having 6 to 10 carbon atoms, 3 to represents 10 cycloalkyl groups, halogen atoms, nitro groups, hydroxyl groups or mercapto groups, and q represents an integer value of 0 to 4. When q is 2 to 4, Ra may be the same within the same ring Each Rb is independently an alkyl group having 1 to 10 carbon atoms, an alkyloxy group or an alkylthio group, an aryl group having 6 to 10 carbon atoms, an aryloxy group or an arylthio group having 3 to 10 carbon atoms. represents a cycloalkyl group, 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 is the average number of repeating units and represents a numerical value of 0.5 to 20.)

It is preferable that the cured product of the present invention is obtained by subjecting the curable resin composition to a curing reaction.

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

The circuit board of the present invention is preferably obtained by laminating the prepreg and copper foil, and thermocompression molding.

The build-up film of the present invention preferably contains the curable resin composition.

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

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

According to the curable resin composition of the present invention, the cured product obtained from the curable resin composition has both excellent heat resistance and dielectric properties, and a curable resin composition having these properties, It is possible to provide cured products, prepregs, circuit boards, build-up films, semiconductor sealing materials, and semiconductor devices obtained from the curable resin composition, which is useful.

The present invention will be described in detail below.

The present invention relates to a curable resin composition characterized by containing a maleimide (A) having an indane skeleton and a cyanate ester compound (B). Among them, the maleimide (A) is preferably represented by the following general formula (1). Since the maleimide (A) has an indane skeleton, the ratio of polar functional groups in the structure of the maleimide (A) is small compared to conventional maleimides, and thus the dielectric properties are excellent, which is preferable. In addition, cured products using conventional maleimide resins tend to be brittle, and there is concern that they may be inferior in brittleness resistance. Improvement is also expected and desirable.

In the general formula (1) above, each Ra is independently an alkyl group, an alkyloxy 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, and 3 carbon atoms. 1 to 10 (preferably 5 to 10) cycloalkyl groups, halogen atoms, nitro groups, hydroxyl groups or mercapto groups; q is an integer of 0 to 4; When q is 2 to 4, Ra may be the same or different within the same ring. Rb each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group or an alkylthio group, an aryl group having 6 to 10 carbon atoms, an aryloxy group or an arylthio group, a cycloalkyl group having 3 to 10 carbon atoms, or a halogen atom. , represents a hydroxyl group or a mercapto group, and r represents an integer of 0 to 3. When r is 2-3, Rb may be the same or different within the same ring. n is the average number of repeating units and shows a numerical value of 0.5-20. When r and q are 0, Ra and Rb each represent a hydrogen atom.

Ra in the general formula (1) is preferably an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. By having an alkyl group of ∼4 or the like, the solvent solubility is improved due to the decrease in planarity and crystallinity in the vicinity of the maleimide group, and a cured product can be obtained without impairing the reactivity of the maleimide group. This is a possible preferred mode.

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

It is preferable that r in the general formula (1) is 0 and Rb is a hydrogen atom, and r is 1 to 3 and Rb is an alkyl group having 1 to 4 carbon atoms and 3 carbon atoms It is preferably at least one selected from the group consisting of a cycloalkyl group having 6 to 6 and an aryl group having 6 to 10 carbon atoms, and in particular, r is 0 and Rb is a hydrogen atom. Therefore, steric hindrance is reduced during the formation of the indane skeleton in maleimide, which is advantageous and preferable for the production (synthesis) of maleimide.

<Method for producing maleimide (A) having an indane skeleton>
A method for producing the maleimide (A) will be described below.

In the following general formula (2), Rc each independently represents a monovalent functional group selected from the group consisting of the following general formulas (3) and (4), and at least one of two Rc ortho to Rc A compound in which the position is a hydrogen atom, and Rb and r are the same as above.

In the following general formula (5), at least one of the ortho- and para-positions of the amino group is a hydrogen atom, and Ra and q are aniline or a derivative thereof, each of which is the same as described above; An intermediate amine compound represented by the following general formula (6) can be obtained by reacting a compound of the following general formula (2) with a compound of the following general formula (5) in the presence of an acid catalyst. Ra, Rb, q, and r in the following general formula (6) are the same as above.

In the intermediate amine compound represented by the above general formula (6), the structure contains the following general formula (7) having an indane skeleton, and in the aniline or its derivative represented by the above general formula (5), q is 3 or less and at least two of the ortho and para positions of the amino group are hydrogen atoms, the structure represented by the following general formula (8) is obtained. However, Ra, Rb, q and r in the following general formula (8) are the same as above, and m is the number of repeating units and is an integer of 1-20. A structure represented by the following general formula (8) may also be included in the structure of the above general formula (6).

In the indane skeleton (see general formula (7) above), which is a feature of the maleimide (A) used in the present invention, the average repeating unit number n has a low melting point (low softening point), a low melt viscosity, and good handling properties. In order to make it excellent, the average repeating unit number n (average value) is 0.5 to 20, preferably 0.7 to 10.0, more preferably 0.95 to 10.0 , More preferably 0.98 to 9.0, more preferably 0.99 to 8.0, still more preferably 1.0 to 7.0, still more preferably 1.0 to 6.0 is. By having an indane skeleton in the structure of the maleimide (A), it has excellent solvent solubility as compared with maleimides that have been used so far, which is a preferred embodiment. If n is less than 0.5, the content of the high-melting substance in the structure of the maleimide (A) is high, the solvent solubility is poor, and the high-molecular-weight component that contributes to flexibility is reduced. Since the ratio is low, the brittleness resistance of the resulting cured product may be lowered, and the flexibility and flexibility may also be lowered, which is not preferable. On the other hand, if n exceeds 20, there is a concern that the heat resistance may be deteriorated, and furthermore, the high molecular weight component may become too large, and when molding the cured product, the fluidity may decrease and the handling property may be deteriorated. and is not preferred. The value of n is preferably 0.5 to 10.0, more preferably 0.95 to 10.0, from the viewpoint of high heat distortion temperature, high glass transition temperature, and the like.

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

In addition, examples of the compound (a) include 2-chloro-1,4-diisopropenylbenzene, 2-chloro-1,4-bis(α-hydroxyisopropyl)benzene, 2-bromo-1,4-di Isopropenylbenzene, 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, 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-diisopropenyl Benzene, 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)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-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-diisopropenylbenzene and 5-cyclohexyl-1,3-bis(α-hydroxyisopropyl)benzene.

The substituent contained in the compound (a) is not particularly limited, and the compounds exemplified above can be used. The resulting maleimides are less likely to stack together, and crystallization of the maleimides is less likely to occur.

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

When the maleimide group is directly bonded to the benzene ring, such as conventional maleimide (for example, N-phenylmaleimide), the state in which the benzene ring and the five-membered maleimide ring are aligned on the same plane is stable. Therefore, stacking is likely to occur, resulting in high crystallinity. Therefore, it becomes a cause of inferior solvent solubility. On the other hand, in the case of the present invention, the compound (b) is not particularly limited, and the compounds exemplified above can be used. When it has a group, the benzene ring and the five-membered maleimide ring take a twisted conformation due to the steric hindrance of the methyl group, making it difficult to stack, resulting in reduced crystallinity and improved solvent solubility, which is a preferred embodiment. . However, if the steric hindrance is too large, the reactivity during the synthesis of maleimide may be inhibited. Therefore, it is preferable to use, for example, a compound (b) having an alkyl group having 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 compound (a) and the compound (b) are mixed in a molar ratio of the compound (b) to the compound (a). The ratio (compound (b) / compound (a)) is preferably 0.1 to 2.0, more preferably 0.2 to 1.0, and after the charging reaction (first stage), the compound ( b) is further added in an amount of preferably 0.5 to 20.0, more preferably 0.7 to 5.0 in molar ratio to the previously added compound (a), and reacted (second step) Thus, a maleimide (A) having an indane skeleton can be obtained. In addition, this two-step reaction gives favorable results in terms of the completion of the reaction and also from the point of view of handleability and the like. In the reaction of the first stage, the molar ratio of the compound (b) to the previously added compound (a) (compound (b)/compound (a)) is preferably 0.10 to 0.49. , more preferably 0.15 to 0.40, and still more preferably 0.20 to 0.39, a wide molecular weight distribution, a low content of low molecular weight high-melting substances, and a high Since the proportion of the molecular weight component is high, it is possible to obtain an intermediate amine compound and a maleimide that are excellent in solvent solubility and can contribute to flexibility and brittleness resistance, which is preferable.

The acid catalyst used in the reaction includes, for example, 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, activated clay, Acid clay, silica alumina, zeolite, solid acids such as strongly acidic ion exchange resins, heteropolyhydrochloric acid, etc. can be mentioned, but after the reaction, solid acids that can be easily removed by filtration are preferred from the viewpoint of handlinkability. When other acids are used, neutralization with a base and washing with water are preferably carried out after the reaction.

The amount of the acid catalyst is blended in the range of 5 to 40 parts by mass with respect to 100 parts by mass of the total amount of the compound (a) and the compound (b) which are initially charged raw materials. , 5 to 30 parts by mass is preferable from the viewpoint of handling and economy. The reaction temperature may generally be in the range of 100 to 300°C, but 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 reaction time, if the reaction time is short, the reaction will not proceed completely, and if the reaction time is long, side reactions such as thermal decomposition of the product will occur. The range is 2 to 48 hours, preferably 2 to 24 hours in total, more preferably 4 to 24 hours in total, still more preferably 4 to 12 hours in total, A total of 8 to 12 hours is more preferable for reducing low molecular weight components and increasing high molecular weight components.

In the method for producing the intermediate amine compound, since aniline or a derivative thereof also serves as a solvent, other solvents may not necessarily be used, but solvents may be used. For example, in the case of a reaction system that also serves as a dehydration reaction, specifically, when reacting a compound having an α-hydroxypropyl group as a raw material, a solvent capable of azeotropic dehydration such as toluene, xylene, or chlorobenzene is used. Alternatively, after the dehydration reaction is completed, the solvent is distilled off and then the reaction is carried out within the above reaction temperature range.

The maleimide (A) used in the present invention is prepared by charging the intermediate amine compound represented by the general formula (6) obtained by the above method into a reactor, dissolving it in an appropriate solvent, and then adding maleic anhydride and a catalyst. After the reaction, unreacted maleic anhydride and other impurities are removed by washing with water or the like, and the solvent is removed by reducing the pressure. Moreover, you may use a dehydrating agent at the time of reaction.

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

上記一般式（９）中のＲａ、Ｒｂ、ｑ、ｒ及びｍは上記と同様のものを示す。

Ra, Rb, q, r and m in the general formula (9) are the same as 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, N,N-dimethylformamide, N, Aprotic solvents such as N-dimethylacetamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, acetonitrile and sulfolane, cyclic ethers such as dioxane and tetrahydrofuran, esters such as ethyl acetate and butyl acetate, benzene, toluene, xylene and the like, and these may be used alone or in combination.

In the maleimidation reaction, the intermediate amine compound and maleic anhydride are preferably blended such that the equivalent ratio of maleic anhydride to the amino equivalent of the intermediate amine compound is in the range of 1 to 1.5, more preferably. is charged at 1.1 to 1.2, and reacted in an organic solvent having a mass ratio of 0.5 to 50, preferably 1 to 5, with respect to the total amount of the intermediate amine compound and maleic anhydride. is a preferred embodiment.

Examples of catalysts used in the maleimidation reaction include inorganic salts such as acetates, chlorides, bromides, sulfates, and nitrates of nickel, cobalt, sodium, calcium, iron, lithium, and manganese; phosphoric acid, hydrochloric acid, and sulfuric acid; Inorganic acids such as oxalic acid, organic acids such as benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, fluoromethanesulfonic acid, solids such as activated clay, acid clay, silica alumina, zeolite, strongly acidic ion exchange resin Acids, heteropolyhydrochloric acid and the like can be mentioned, but toluenesulfonic acid is particularly preferably used.

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

The amounts of the catalyst and dehydrating agent used in the maleimidation reaction are not particularly limited. 0.001 to 0.5 mol, more preferably 0.01 to 0.3 mol, and the dehydrating agent can be used in an amount of 1 to 3 mol, preferably 1 to 1.5 mol.

As the reaction conditions for the maleimidation, the intermediate amine compound and maleic anhydride are charged, and the temperature range is 10 to 100° C., preferably 30 to 50° C., for 0.5 to 12 hours, preferably 1 to 8 hours. After the reaction, the catalyst is added and reacted at a temperature range of 90 to 130° C., preferably 105 to 120° C. for 2 to 24 hours, preferably 4 to 10 hours. 6 to 10 hours is more preferred for the increase in high molecular weight components. After the reaction, unreacted maleic anhydride and other impurities are removed by washing with water or the like, and the low molecular weight components are reduced and the high molecular weight components are increased by heat aging.

Since the maleimide (A) is excellent in low dielectric constant and low dielectric loss tangent, the molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) calculated from gel permeation chromatography (GPC) measurement is It is preferably in the range of 1.0 to 10.0, more preferably 1.1 to 9.0, still more preferably 1.1 to 8.0, still more preferably 1.2 to 5.0 is more preferably 1.2 to 4.0, more preferably 1.3 to 3.8, particularly preferably 1.3 to 3.6, most preferably 1.3 to 3.4. From the GPC chart obtained from the GPC measurement, when the molecular weight distribution is wide and the high molecular weight component is large, the proportion of the high molecular weight component contributing to flexibility increases. This is a preferred embodiment because it is less brittle than other materials, and a cured product with excellent flexibility and softness can be obtained.

<GPC measurement>
The molecular weight distribution (Mw/Mn) of maleimide (A) was measured based on gel permeation chromatography (GPC) under the following conditions.
Measuring device: "HLC-8320 GPC" 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 + Tosoh Corporation Made by "TSK-GEL G4000HXL"
Detector: RI (differential refractometer)
Data processing: "GPC Workstation EcoSEC-WorkStation" manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40°C
Developing solvent Tetrahydrofuran
Flow rate 1.0 ml/min Standard: The following monodisperse polystyrene having a known molecular weight was used in accordance with the measurement manual of the "GPC Workstation EcoSEC-WorkStation".
(Polystyrene used)
"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: 50 µl of a tetrahydrofuran solution of 1.0% by mass in terms of resin solid content of maleimide obtained in Synthesis Example filtered through a microfilter.

<Cyanate ester compound (B)>
The curable resin composition of the present invention is characterized by containing a cyanate ester compound (B) in addition to the maleimide (A) having an indane skeleton. Since the cyanate ester compound (B) has excellent dielectric properties such as dielectric constant and dielectric loss tangent, it maintains a sufficiently low dielectric constant even in a high frequency band (high frequency region) from the MHz band to the GHz band, Since it is possible to prepare a curable resin composition capable of obtaining a cured product exhibiting a low dielectric loss tangent, it is useful as a molding material for high frequencies. In addition, by reaction with the maleimide (A) having the indane skeleton, it can act as a curing agent and produce three-dimensional cross-linking, and has heat resistance, low thermal expansion, adhesion, and further mechanical properties and chemical resistance. A cured product having excellent properties can be obtained, which is a preferred embodiment.

As the cyanate ester compound (B), for example, bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, bisphenol S type cyanate ester resin, bisphenol sulfide type cyanate ester resin, phenylene ether type Cyanate ester resin, naphthylene ether type cyanate ester resin, biphenyl type cyanate ester resin, tetramethylbiphenyl type cyanate ester resin, polyhydroxynaphthalene type cyanate ester resin, phenol novolac type cyanate ester resin, cresol novolac type cyanate ester resin, triphenyl Methane type cyanate ester resin, tetraphenylethane type cyanate ester resin, dicyclopentadiene-phenol addition reaction type cyanate ester resin, phenol aralkyl type cyanate ester resin, naphthol novolac type cyanate ester resin, naphthol aralkyl type cyanate ester resin, naphthol-phenol co-condensed novolak-type cyanate ester resin, naphthol-cresol co-condensed novolac-type cyanate ester resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin-type cyanate ester resin, biphenyl-modified novolac-type cyanate ester resin, anthracene-type cyanate ester resin, etc. . Each of these may be used alone, or two or more of them may be used in combination.

Among the cyanate ester compounds (cyanate ester resins), bisphenol A-type cyanate ester resins, bisphenol F-type cyanate ester resins, bisphenol E-type cyanate ester resins, and polyhydroxynaphthalene are particularly useful in terms of obtaining cured products with excellent heat resistance. It is preferable to use a type cyanate ester resin, a naphthylene ether type cyanate ester resin, or a novolac type cyanate ester resin, and a dicyclopentadiene-phenol addition reaction type cyanate ester resin is preferable in terms of obtaining a cured product having excellent dielectric properties. .

A curing agent other than the cyanate ester compound (B) may be added to the curable resin composition of the present invention as long as it does not impair the curing of the present invention. The cyanate ester compound (B) is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and particularly 80% by mass or more with respect to 100% by mass of the total amount of the curing agent. Preferably, 90% by mass or more is most preferable.

Examples of curing agents other than the cyanate ester compound (B) include amine-based compounds, amide-based compounds, acid anhydride-based compounds, phenol-based compounds, polyphenylene ether-based compounds, and unsaturated double bond-containing substituents. and diene-based polymers. These curing agents may be used alone or in combination of two or more.

Examples of the amine compounds include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF3-amine complexes, guanidine derivatives and the like.

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

Examples of the acid anhydride compounds include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, Methylhexahydrophthalic anhydride and the like can be mentioned.

Examples of the phenol-based compounds include phenol novolac resins, cresol novolac resins, aromatic hydrocarbon formaldehyde resin-modified phenol resins, dicyclopentadiene phenol addition type resins, phenol aralkyl resins (Zyloc resins), and resorcinol novolac resins. Polyhydric phenol novolac resin synthesized from polyhydric hydroxy compound and formaldehyde, naphthol aralkyl resin, trimethylolmethane resin, tetraphenylol ethane resin, naphthol novolak resin, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolac resin , biphenyl-modified phenolic resin (polyhydric phenol compound with phenolic nucleus linked by bismethylene group), biphenyl-modified naphthol resin (polyhydric naphthol compound with phenolic nucleus linked with bismethylene group), aminotriazine-modified phenolic resin (melamine, benzoguanamine Polyhydric phenol compounds such as polyhydric phenol compounds in which a phenol nucleus is linked by such as) and alkoxy group-containing aromatic ring-modified novolac resins (polyhydric phenol compounds in which phenol nuclei and alkoxy group-containing aromatic rings are linked by formaldehyde). be done.

The polyphenylene ether-based compound has, for example, a structure represented by the following general formula (10) or (11).

Rd in the general formulas (10) and (11) is each independently 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 alkyloxycarbonyl group having 2 to 5 carbon atoms, and an alkylcarbonyloxy group having 2 to 5 carbon atoms. , an alkylsulfonyl group having 1 to 5 carbon atoms, and the like. Examples of terminal structures of the structures represented by the general formulas (10) and (11) include those having a hydroxyl group or a reactive double bond-containing group. Also, s is an integer value of 1-30, and t and u are also integer values of 1-30.

Examples of the alkyl group having 1 to 5 carbon atoms include, but are not limited to, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, and propyl group. be done.

Examples of the alkenyl group having 1 to 5 carbon atoms include, but are not limited to, vinyl group, 1-propenyl group, 1-butenyl group, 1-pentenyl group, isopropenyl group and the like.

Examples of the cycloalkyl group having 3 to 5 carbon atoms include, but are not particularly limited to, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a methylcyclobutyl group, and the like.

Examples of the alkoxy group having 1 to 5 carbon atoms include, but are not particularly limited to, a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butoxy group and a pentyloxy group.

Examples of the thioether group having 1 to 5 carbon atoms include, but are not limited to, methylthio, ethylthio, propylthio, isopropylthio, butylthio, pentylthio and the like.

Examples of the alkylcarbonyl group having 2 to 5 carbon atoms include, but are not limited to, methylcarbonyl, ethylcarbonyl, propylcarbonyl, isopropylcarbonyl, and butylcarbonyl groups.

Examples of the alkyloxycarbonyl group having 2 to 5 carbon atoms include, but are not particularly limited to, a methyloxycarbonyl group, an ethyloxycarbonyl group, a propyloxycarbonyl group, an isopropyloxycarbonyl group, and a butyloxycarbonyl group.

Examples of the alkylcarbonyloxy group having 2 to 5 carbon atoms include, but are not particularly limited to, a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, an isopropylcarbonyloxy group, a butylcarbonyloxy group, and the like.

Examples of the alkylsulfonyl group having 1 to 5 carbon atoms include, but are not limited to, methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, isopropylsulfonyl group, butylsulfonyl group, pentylsulfonyl group and the like.

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, and is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. A hydrogen atom, a methyl group and an ethyl group are more preferred, and a hydrogen atom and a methyl group are particularly preferred.

Y in (11) above includes 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, but 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 and the like. 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 and bisphenol A are preferred. , tetramethylbisphenol A is more preferred.

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), so Y is an aromatic compound having two phenolic hydroxyl groups. It becomes a divalent aromatic group derived from a group compound.

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

Examples of the diene-based polymer include unmodified diene-based polymers that are not modified with polar groups. Here, the polar group is a functional group that affects dielectric properties, and includes, for example, a phenol group, an amino group, an epoxy group, and the like. The diene-based polymer is not particularly limited, and for example, 1,2-polybutadiene, 1,4-polybutadiene, or the like can be used.

As the diene-based 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 can also be used.

If necessary, the curable resin composition of the present invention can be used in combination with a curing accelerator. Various curing accelerators can be used, but since the cyanate ester compound (B) is used, for example, phenols, amines, Lewis acids, tertiary sulfonium salts, quaternary ammonium salts, quaternary phosphonium Salts, epoxy group-containing compounds, and the like are included. Among these, nonylphenol, 2,4,6-tris(dimethylaminomethyl)phenol, carboxylates of copper, lead, tin, manganese, nickel, iron, zinc, cobalt, etc., titanium tetra-n-butoxide and its polymers , pentadionate salts of copper, nickel, cobalt and the like, tetrabutylammonium bromide, tetrabutylphosphonium chloride, tetraphenylphosphonium tetra(methylphenyl)borate, zinc octylate and the like can be used. Further, the curing accelerator is preferable because it has high compatibility with the cyanate ester compound (B) and the curing reaction proceeds smoothly. Furthermore, among these, tetraphenylphosphonium tetra(methylphenyl)borate is particularly preferred. The use of tetraphenylphosphonium tetra(methylphenyl)borate as the curing accelerator is preferable because the curing reaction progresses more quickly than other curing accelerators. Further, the amount of the curing accelerator to be added is preferably, for example, 0.001 to 1.00 parts by mass with respect to 100 parts by mass of the cyanate ester compound (B).

<Preparation of curable resin composition>
The curable resin composition of the present invention comprises a maleimide (A) having an indane skeleton (hereinafter sometimes referred to as "component (A)"), and a cyanate ester compound (B) (hereinafter referred to as "component (B)" Sometimes called.) is characterized by containing. As the component (B), the reaction with the component (A) can produce three-dimensional cross-linking, and a cured product having excellent dielectric properties and heat resistance can be obtained, which is a preferred embodiment. .

The blending ratio (parts by mass) of the component (A) and the component (B) is preferably 90:10 to 10:90, more preferably 90:10 to 10:90 (A):(B). , 80:20 to 20:80, more preferably 75:25 to 25:75. By adjusting the compounding ratio within the above range, excellent heat resistance, low dielectric constant and low dielectric loss tangent can be obtained, and flexibility can be exhibited, which is preferable.

The curable resin composition of the present invention contains alkenyl group-containing compounds, such as bismaleimides other than the maleimide (A), allyl ether compounds, allylamine compounds, triallyl cyanurate, as long as the object is not impaired. Alkenylphenol compounds, vinyl group-containing polyolefin compounds, and the like can also be added. Other thermosetting resins such as thermosetting polyimide resins, epoxy resins, phenol resins, active ester resins, benzoxazine resins, cyanate resins, etc. can also be blended appropriately according to the purpose.

The curable resin composition of the present invention can be blended with a non-halogen flame retardant that does not substantially contain halogen atoms in order to exhibit flame retardancy within a range that does not impair the purpose. Examples of the non-halogen flame retardants include phosphorus flame retardants, nitrogen flame retardants, silicone flame retardants, inorganic flame retardants, organic metal salt flame retardants, etc. These are used alone or in combination. be able to.

The curable resin composition of the present invention may optionally contain an inorganic filler. Examples of the inorganic filler include fused silica, crystalline silica, alumina, silicon nitride, and aluminum hydroxide. When the blending amount of the inorganic filler is particularly large, it is preferable to use fused silica. The fused silica may be crushed or spherical, but it is preferable to mainly use spherical fused silica in order to increase the blending amount of fused silica and suppress an increase in the melt viscosity of the molding material. Furthermore, in order to increase the compounding amount of spherical silica, it is preferable to appropriately adjust the particle size distribution of spherical silica. Considering flame retardancy, the filling rate is preferably as high as possible, and is particularly preferably 20% by mass or more relative to the total amount of the curable resin composition. Moreover, when using the said curable resin composition for applications, such as a conductive paste detailed below, conductive fillers, such as silver powder and copper powder, can be used.

The curable resin composition of the present invention may optionally contain various compounding agents such as silane coupling agents, release agents, pigments and emulsifiers.

<Cured product>
It is preferable that the cured product of the present invention is obtained by subjecting the curable resin composition to a curing reaction. The curable resin composition is obtained by uniformly mixing the components described above, and can be easily cured by the same method as a conventionally known method. Examples of the cured product include molded cured products such as laminates, cast products, adhesive layers, coating films, and films.

The curing (thermal curing) reaction can be easily carried out without a catalyst, but if you want to make the reaction faster, you can use a polymerization initiator such as an organic peroxide, an azo compound, a phosphine compound, or a tertiary amine. Addition of a basic catalyst such as is effective. For example, there are benzoyl peroxide, dicumyl peroxide, azobisisobutyronitrile, triphenylphosphine, triethylamine, imidazoles, and the like. preferable.

<Prepreg>
The prepreg of the present invention preferably has a reinforcing base material and a semi-cured product of the curable resin composition impregnated in the reinforcing base material. As a method for producing the prepreg, a known method can be used. A prepreg can be obtained by semi-curing (or uncuring) the curable resin composition by heat-treating the material.

Examples of the organic solvent include toluene, xylene, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, methyl ethyl ketone (MEK), methyl isobutyl ketone, dioxane, tetrahydrofuran, and the like. , can be used alone or as a mixed solvent of two or more.

The reinforcing base material to be impregnated with the resin varnish includes inorganic fibers such as glass fiber, polyester fiber and polyamide fiber, woven fabrics and non-woven fabrics made of organic fibers, mats, paper, etc. These can be used alone or in combination. can be used.

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

The conditions for the heat treatment of the prepreg are appropriately selected depending on the type and amount of the organic solvent, catalyst, and various additives used. This is done under such conditions.

<Heat resistant materials and electronic materials>
Since the cured product obtained from the curable resin composition of the present invention is excellent in heat resistance and dielectric properties, it can be suitably used for heat-resistant members and electronic members. In particular, it can be suitably used for circuit boards, semiconductor sealing materials, semiconductor devices, build-up films, build-up substrates, adhesives, resist materials, and the like. Moreover, it can be suitably used as a matrix resin for fiber-reinforced resins, and is particularly suitable as a highly heat-resistant prepreg. In addition, the maleimide (A) having an indane skeleton contained in the curable resin composition exhibits excellent solubility in various solvents, and can be made into a coating. The heat-resistant members and electronic members obtained in this way can be suitably used for various applications, for example, industrial machine parts, general machine parts, automobile/railroad/vehicle parts, aerospace-related parts, electronic/electrical parts, Building materials, containers/packaging members, daily necessities, sports/leisure goods, housing members for wind power generation, etc., but not limited to these.

Typical products manufactured using the curable resin composition of the present invention will be described below with reference to examples.

<Circuit board>
In the present invention, the circuit board is preferably obtained by laminating the prepreg and copper foil, and thermocompression molding. Specifically, as a method for obtaining a circuit board from the curable resin composition of the present invention, the above prepreg is laminated by a conventional method, appropriately overlaid with copper foil, and heated at 170 to 300 ° C. under a pressure of 1 to 10 MPa. for 10 minutes to 3 hours at a temperature of about 10 minutes to 3 hours.

<Semiconductor sealing material>
In the present invention, the semiconductor sealing material preferably contains the curable resin composition. Specifically, as a method for obtaining a semiconductor encapsulant from the curable resin composition of the present invention, the curable resin composition is further added with optional ingredients such as a curing accelerator and an inorganic filler. If necessary, an extruder, a kneader, a roll, or the like is used to sufficiently melt and mix the ingredients until they become uniform. At that time, fused silica is usually used as the inorganic filler, but when it is used as a high thermal conductive semiconductor encapsulant for power transistors and power ICs, crystalline silica, alumina, and nitride, which have higher thermal conductivity than fused silica, are used. It is preferable to use high filling of silicon or the like, or fused silica, crystalline silica, alumina, silicon nitride, or the like. The filling rate is preferably in the range of 30 to 95 parts by mass of the inorganic filler per 100 parts by mass of the curable resin composition. In order to reduce the coefficient, it is more preferably 70 parts by mass or more, and even more preferably 80 parts by mass or more.

<Semiconductor device>
In the present invention, the semiconductor device preferably contains a cured product obtained by heating and curing the semiconductor sealing material. Specifically, for molding a semiconductor package to obtain a semiconductor device from the curable resin composition of the present invention, the semiconductor encapsulant is cast, or molded using a transfer molding machine, an injection molding machine, or the like. A method of heat curing at 50 to 250° C. for 2 to 10 hours can be mentioned.

<Build-up board>
A method of obtaining a build-up substrate from the curable resin composition of the present invention includes a method of steps 1 to 3. In step 1, first, the curable resin composition appropriately blended with rubber, filler, etc. is applied to a circuit board having a circuit formed thereon by using a spray coating method, a curtain coating method, or the like, and then cured. In step 2, if necessary, the circuit board to which the curable resin composition has been applied is drilled with a predetermined through hole or the like, treated with a roughening agent, and the surface is washed with hot water. Concavo-convex portions are formed on the substrate and plated with a metal such as copper. In step 3, the operations of steps 1 and 2 are repeated as desired to alternately build up resin insulating layers and conductor layers having a predetermined circuit pattern to form a buildup board. In the above process, it is preferable to form the through-hole portion after forming the outermost resin insulating layer. In addition, the build-up board in the present invention is obtained by heat-pressing a copper foil with a resin obtained by semi-curing the resin composition on a copper foil onto a wiring board on which a circuit is formed at 170 to 300 ° C. It is also possible to produce a build-up board by omitting the steps of forming a hardened surface and plating.

<Build-up film>
The build-up film of the present invention preferably contains the curable resin composition. As a method of obtaining a build-up film from the curable resin composition of the present invention, for example, the curable resin composition is applied onto a support film and then dried to form a resin composition layer on the support film. method. When the curable resin composition of the present invention is used for a build-up film, the film is softened under the lamination temperature conditions (usually 70° C. to 140° C.) in the vacuum lamination method, and simultaneously with the lamination of the circuit board, it is applied to the circuit board. It is essential to exhibit fluidity (resin flow) that allows resin filling in existing via holes or through holes, and it is preferable to blend the above components so as to exhibit such properties. In addition, in the resulting build-up film and circuit board (copper-clad laminate, etc.), there is no phenomenon such as locally different characteristic values due to phase separation, etc., and constant performance can be obtained at any part. appearance uniformity is required.

Here, the diameter of the through hole of the circuit board is usually 0.1 to 0.5 mm, and the depth is usually 0.1 to 1.2 mm, and it is usually preferable to allow resin filling within this range. When both sides of the circuit board are laminated, it is desirable to fill the through holes by about half.

As a specific method for producing the build-up film described above, after preparing a varnished resin composition by blending an organic solvent, the varnished resin composition is applied to the surface of the support film (Y). and then drying the organic solvent by heating or blowing hot air to form the resin composition layer (X).

Examples of the organic solvent used here include ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; cellosolve, butyl carbitol, and the like; Carbitols, toluene, aromatic hydrocarbons such as xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. are preferably used, and the nonvolatile content is 30 to 60% by mass. preferable.

The thickness of the resin composition layer (X) to be formed should normally be greater than or equal to the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer (X) is preferably 10 to 100 μm. In addition, the resin composition layer (X) in the present invention may be protected with a protective film to be described later. By protecting the surface of the resin composition layer with a protective film, it is possible to prevent the surface of the resin composition layer from being dusted or scratched.

The above support film and protective film include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polycarbonates, polyimides, and metals such as release paper, copper foil, and aluminum foil. foil and the like. The support film and protective film may be subjected to release treatment in addition to mud treatment and corona treatment. Although the thickness of the support film is not particularly limited, it is usually 10 to 150 μm, preferably 25 to 50 μm. Also, the thickness of the protective film is preferably 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. If the support film (Y) is peeled off after the resin composition layer constituting the build-up film is cured by heating, it is possible to prevent the adhesion of dust and the like during the curing process. When peeling after curing, the support film is normally subjected to a release treatment in advance.

A multilayer printed circuit board can be produced from the build-up film obtained as described above. For example, when the resin composition layer (X) is protected by a protective film, after removing these, the resin composition layer (X) is placed on one or both sides of the circuit board so as to be in direct contact with the circuit board. , for example, by a vacuum lamination method. The method of lamination may be a batch type or a continuous roll type. If necessary, the build-up film and the circuit board may be heated (preheated) before lamination. As for lamination conditions, it is preferable that the pressure bonding temperature (laminating temperature) is 70 to 140° C., and the pressure bonding pressure is 1 to 11 kgf/cm ² (9.8×10 ⁴ to 107.9×10 ⁴ N/m ² ). It is preferable to laminate under a reduced pressure of 20 mmHg (26.7 hPa) or less.

<Conductive paste>
Examples of the method of obtaining the conductive paste from the curable resin composition of the present invention include a method of dispersing conductive particles in the composition. The conductive paste can be a paste resin composition for circuit connection or an anisotropic conductive adhesive, depending on the type of conductive particles used.

EXAMPLES Next, the present invention will be described in detail with reference to examples and comparative examples. In the following, "parts" and "%" are based on mass unless otherwise specified. The softening point, amine equivalent, GPC, and FD-MS spectrum were measured and evaluated under the following conditions.

1) Softening point Measuring method: The softening point (°C) of the intermediate amine compounds obtained in the synthesis examples shown below was measured according to JIS K7234 (ring and ball method).

2) Amine Equivalent The amine equivalent of the intermediate amine compound was measured by the following measuring method.
Approximately 2.5 g of the sample intermediate amine compound, 7.5 g of pyridine, 2.5 g of acetic anhydride, and 7.5 g of triphenylphosphine were accurately weighed in a 500 mL Erlenmeyer flask with a common stopper, and the temperature was adjusted to 120°C with a cooling tube attached. The mixture is heated to reflux for 150 minutes in an oil bath set to .
After cooling, 5.0 mL of distilled water, 100 mL of propylene glycol monomethyl ether, and 75 mL of tetrahydrofuran were added and titrated with a 0.5 mol/L potassium hydroxide-ethanol solution by potentiometric titration. A blank test was performed in the same manner and corrected.
Amine equivalent (g / eq.) = (S × 2,000) / (Blank-A)
S: amount of sample (g)
A: Consumption (mL) of 0.5 mol/L potassium hydroxide-ethanol solution
Blank: consumption (mL) of 0.5 mol/L potassium hydroxide-ethanol solution in blank test

3) GPC Measurement Measurement was performed using the following measurement apparatus and measurement conditions, and GPC charts (FIGS. 1 to 9) of the maleimides obtained in the Synthesis Examples shown below were obtained. From the results of the GPC chart, 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 maleimide to the number average molecular weight (Mn) Measured and calculated based on Specifically, for compounds with n = 0 to 4, the theoretical molecular weight and the molecular weight of each measured value in GPC are plotted on a scatter diagram, an approximate straight line is drawn, and the number from the point indicated by the measured value Mn (1) on the straight line The average molecular weight (Mn) was determined and n was calculated.
Measuring device: "HLC-8320 GPC" 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 + Tosoh Corporation Made by "TSK-GEL G4000HXL"
Detector: RI (differential refractometer)
Data processing: "GPC Workstation EcoSEC-WorkStation" manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40°C
Developing solvent Tetrahydrofuran
Flow rate 1.0 ml/min Standard: The following monodisperse polystyrene having a known molecular weight was used in accordance with the measurement manual of the "GPC Workstation EcoSEC-WorkStation".
(Polystyrene used)
"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: 50 µl of a tetrahydrofuran solution of 1.0% by mass in terms of resin solid content of maleimide obtained in Synthesis Example filtered through a microfilter.

4) FD-MS spectrum The FD-MS spectrum was measured using the following measurement equipment and measurement conditions.
Measuring device: JMS-T100GC AccuTOF
Measurement conditions Measurement range: m / z = 4.00 to 2000.00
Rate of change: 51.2mA/min
Final current value: 45mA
Cathode voltage: -10 kV
Recording interval: 0.07sec

[Synthesis Example 1] Synthesis of Maleimide Compound A-1 (1) Synthesis of Intermediate Amine Compound 48.5 g of 2,6-dimethylaniline (0.5 g of 2,6-dimethylaniline) was placed in a 1 L flask equipped with a thermometer, condenser, Dean-Stark trap and stirrer. 4 mol), α,α'-dihydroxy-1,3-diisopropylbenzene 272.0 g (1.4 mol), xylene 280 g and activated clay 70 g were charged and heated to 120° C. while stirring. Further, the temperature was raised to 210° C. while removing the distilled water with a Dean-Stark tube, and the reaction was carried out for 3 hours. After cooling to 140° C., 145.4 g (1.2 mol) of 2,6-dimethylaniline was charged, the temperature was raised to 220° C., and the reaction was allowed to proceed for 3 hours. After the reaction, air-cooled to 100 ° C., diluted with 300 g of toluene, removed the activated clay by filtration, and distilled off low molecular weight substances such as solvents and unreacted substances under reduced pressure to obtain the following general formula (A-1 364.1 g of the intermediate amine compound represented by ) were obtained. The amine equivalent weight was 298 and the softening point was 70°C.

(2) Maleimidation 131.8 g (1.3 mol) of maleic anhydride and 700 g of toluene were placed in a 2 L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, and stirred at room temperature. Next, 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 dropwise addition was completed, the mixture was allowed to react at room temperature for an additional 2 hours. After adding 37.1 g of p-toluenesulfonic acid monohydrate and heating the reaction solution to cool and separate water and toluene azeotroping under reflux, only toluene was returned to the system and the dehydration reaction was continued for 8 hours. time went After air cooling to room temperature, concentration under reduced pressure, the brown solution was dissolved in 600 g of ethyl acetate, washed three times with 150 g of ion-exchanged water and three times with 150 g of 2% aqueous sodium hydrogen carbonate solution, added with sodium sulfate, dried, and concentrated under reduced pressure. The resulting 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 this maleimide compound A-1, peaks at M+=560, 718 and 876 were confirmed, corresponding to n=0, 1 and 2, respectively. The value of the repeating unit number n in the indane skeleton portion of the maleimide A-1 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG. 1, where n=1.47. The molecular weight distribution (Mw/Mn) was 1.81.

[Synthesis Example 2] Synthesis of Maleimide Compound A-2 (1) Synthesis of Intermediate Amine Compound 48.5 g (0.5 g) of 2,6-dimethylaniline was placed in a 1 L flask equipped with a thermometer, condenser, Dean-Stark trap and stirrer. 4 mol), α,α'-dihydroxy-1,3-diisopropylbenzene 233.2 g (1.2 mol), xylene 230 g and activated clay 66 g were charged and heated to 120° C. while stirring. Further, the temperature was raised to 210° C. while removing the distilled water with a Dean-Stark tube, and the reaction was carried out for 3 hours. After cooling to 140° C., 145.4 g (1.2 mol) of 2,6-dimethylaniline was charged, the temperature was raised to 220° C., and the reaction was allowed to proceed for 3 hours. After the reaction, air-cooled to 100 ° C., diluted with 300 g of toluene, removed the activated clay by filtration, and distilled off low molecular weight substances such as solvents and unreacted substances under reduced pressure to obtain the following general formula (A-2 ) to obtain 278.4 g of the intermediate amine compound represented by The amine equivalent weight was 294 and the softening point was 65°C.

(2) Maleimidation 107.9 g (1.1 mol) of maleic anhydride and 600 g of toluene were placed in a 2 L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, and stirred at room temperature. Next, 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 dropwise addition was completed, the mixture was allowed to react at room temperature for an additional 2 hours. 27.0 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, and the water and toluene azeotroped under reflux were cooled and separated. time went After air-cooling to room temperature, it was concentrated under reduced pressure. The brown solution was dissolved in 500 g of ethyl acetate, washed with 120 g of ion-exchanged water three times and with 120 g of 2% aqueous sodium hydrogencarbonate solution three times, added with sodium sulfate, dried, and concentrated under reduced pressure. The resulting 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 this maleimide compound A-2, peaks of M+=560, 718 and 876 were confirmed, corresponding to n=0, 1 and 2, respectively. The value of the repeating unit number n in the indane skeleton portion of the maleimide A-2 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG. 2, where n=1.25. The molecular weight distribution (Mw/Mn) was 3.29.

[Synthesis Example 3] Synthesis of Maleimide Compound A-3 (1) Synthesis of Intermediate Amine Compound 48.5 g of 2,6-dimethylaniline (0.5 g of 2,6-dimethylaniline) was placed in a 2 L flask equipped with a thermometer, condenser, Dean-Stark trap and stirrer. 4 mol), α,α'-dihydroxy-1,3-diisopropylbenzene 388.6 g (2.0 mol), xylene 350 g and activated clay 123 g were charged and heated to 120° C. while stirring. Further, the temperature was raised to 210° C. while removing the distilled water with a Dean-Stark tube, and the reaction was carried out for 3 hours. After cooling to 140° C., 145.4 g (1.2 mol) of 2,6-dimethylaniline was charged, the temperature was raised to 220° C., and the reaction was allowed to proceed for 3 hours. After the reaction, air-cool to 100 ° C., dilute with 500 g of toluene, remove the activated clay by filtration, and distill off low molecular weight substances such as solvents and unreacted substances under reduced pressure to obtain the following general formula (A-3 402.1 g of the intermediate amine compound represented by ) were obtained. The amine equivalent weight was 306 and the softening point was 65°C.

(2) Maleimidation 152.1 g (1.5 mol) of maleic anhydride and 700 g of toluene were placed in a 2-L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, and stirred at room temperature. Next, 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 dropwise addition was completed, the mixture was allowed to react at room temperature for an additional 2 hours. 37.5 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, and the water and toluene azeotroped under reflux were cooled and separated. time went After air cooling to room temperature, concentration under reduced pressure, the brown solution was dissolved in 800 g of ethyl acetate, washed three times with 200 g of deionized water and three times with 200 g of 2% aqueous sodium hydrogen carbonate solution, added with sodium sulfate, dried, and concentrated under reduced pressure. The resulting 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 this maleimide compound A-3, peaks of M+=560, 718 and 876 were confirmed, corresponding to n=0, 1 and 2, respectively. When the value of the repeating unit number n (based on the number average molecular weight) in the indane skeleton portion in the maleimide A-3 was determined by GPC, the GPC chart is shown in FIG. 3, where n=1.96. The molecular weight distribution (Mw/Mn) was 1.52.

[Synthesis Example 4] Synthesis of Maleimide Compound A-4 (1) Synthesis of Intermediate Amine Compound 59.7 g (0.7 g) of 2,6-diethylaniline was placed in a 2 L flask equipped with a thermometer, condenser, Dean-Stark trap and stirrer. 4 mol), α,α'-dihydroxy-1,3-diisopropylbenzene 272.0 g (1.4 mol), xylene 350 g and activated clay 94 g were charged and heated to 120° C. while stirring. Further, the temperature was raised to 210° C. while removing the distilled water with a Dean-Stark tube, and the reaction was carried out for 3 hours. After cooling to 140° C., 179.1 g (1.2 mol) of 2,6-diethylaniline was charged, the temperature was raised to 220° C., and the reaction was allowed to proceed for 3 hours. After the reaction, air-cooled to 100 ° C., diluted with 500 g of toluene, removed the activated clay by filtration, and distilled off low molecular weight substances such as solvents and unreacted substances under reduced pressure to obtain the following general formula (A-4 342.1 g of the intermediate amine compound represented by ) were obtained. The amine equivalent weight was 364 and the softening point was 47°C.

(2) Maleimidation 107.9 g (1.1 mol) of maleic anhydride and 600 g of toluene were placed in a 2 L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, and stirred at room temperature. Next, 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 dropwise addition was completed, the mixture was allowed to react at room temperature for an additional 2 hours. 26.8 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, and the water and toluene azeotroped under reflux were cooled and separated. time went After air-cooling to room temperature, it was concentrated under reduced pressure. The brown solution was dissolved in 500 g of ethyl acetate, washed three times with 200 g of ion-exchanged water and three times with 200 g of 2% aqueous sodium hydrogencarbonate solution, added with sodium sulfate, dried, and concentrated under reduced pressure. The resulting 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 this maleimide compound A-4, peaks of M+=616, 774 and 932 were confirmed, corresponding to n=0, 1 and 2, respectively. When the value of the repeating unit number n in the indane skeleton portion in the maleimide A-4 (based on the number average molecular weight) was determined by GPC, the GPC chart is shown in FIG. 4, where n=1.64. The molecular weight distribution (Mw/Mn) was 1.40.

[Synthesis Example 5] Synthesis of Maleimide Compound A-5 (1) Synthesis of Intermediate Amine Compound 70.9 g of 2,6-diisopropylaniline (0.9 g of 2,6-diisopropylaniline) was placed in a 1 L flask equipped with a thermometer, condenser, Dean-Stark trap and stirrer. 4 mol), α,α'-dihydroxy-1,3-diisopropylbenzene 272.0 g (1.4 mol), xylene 350 g and activated clay 97 g were charged and heated to 120° C. while stirring. Further, the temperature was raised to 210° C. while removing the distilled water with a Dean-Stark tube, and the reaction was carried out for 3 hours. After cooling to 140° C. and adding 212.7 g (1.2 mol) of 2,6-diisopropylaniline, the temperature was raised to 220° C. and the reaction was allowed to proceed for 3 hours. After the reaction, air-cool to 100 ° C., dilute with 500 g of toluene, remove the activated clay by filtration, and distill off low molecular weight substances such as solvents and unreacted substances under reduced pressure to obtain the following general formula (A-5 317.5 g of the intermediate amine compound represented by ) were obtained. The amine equivalent weight was 366 and the softening point was 55°C.

(2) Maleimidation 107.9 g (1.1 mol) of maleic anhydride and 600 g of toluene were placed in a 2 L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, and stirred at room temperature. Next, 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 dropwise addition was completed, the mixture was allowed to react at room temperature for an additional 2 hours. 24.8 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, and the water and toluene azeotroped under reflux were cooled and separated. time went After air-cooling to room temperature, it was concentrated under reduced pressure. The brown solution was dissolved in 600 g of ethyl acetate, washed three times with 200 g of ion-exchanged water and three times with 200 g of 2% aqueous sodium hydrogen carbonate solution, added with sodium sulfate, dried, and concentrated under reduced pressure. The resulting 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 this maleimide compound A-5, peaks of M+=672, 830 and 988 were confirmed, corresponding to n=0, 1 and 2, respectively. The value of the repeating unit number n in the indane skeleton portion of the maleimide A-5 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG. 5, where n=1.56. The molecular weight distribution (Mw/Mn) was 1.24.

[Synthesis Example 6] Synthesis of Maleimide Compound A-9 (1) Synthesis of Intermediate Amine Compound The same operation was carried out with different times to obtain 345.2 g of an intermediate amine compound represented by the following general formula (A-9). The amine equivalent weight was 348 and the softening point was 71°C.

(2) Maleimidation 407.6 g of a product containing maleimide compound A-9 was obtained in the same manner as in the method for synthesizing maleimide compound A-1 except that the intermediate was replaced with A-9. In the FD-MS spectrum of this maleimide compound A-9, peaks at M+=560, 718 and 876 were confirmed, corresponding to n=0, 1 and 2, respectively. When the value of the repeating unit number n in the indane skeleton portion of the maleimide A-9 (based on the number average molecular weight) was determined by GPC, the GPC chart is shown in FIG. 6, where n=2.59. The molecular weight distribution (Mw/Mn) was 1.49.

[Synthesis Example 7] Synthesis of maleimide compound A-10 The same procedure as in the method for synthesizing the intermediate amine compound A-1 was carried out except that 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 method as in the synthesis of maleimide compound A-1, except that the dehydration reaction under reflux in the maleimidation reaction for the synthesized intermediate amine compound (amine equivalent: 347, softening point: 71° C.) is performed for 10 hours. 415.6 g of a product containing maleimide compound A-10 was obtained. In the FD-MS spectrum of this maleimide compound A-10, peaks at M+=560, 718 and 876 were confirmed, corresponding to n=0, 1 and 2, respectively. The value of the repeating unit number n in the indane skeleton portion of the maleimide A-10 (based on the number average molecular weight) was determined by GPC. The GPC chart is shown in FIG. 7, where n=2.91. The molecular weight distribution (Mw/Mn) was 1.64.

[Synthesis Example 8] Synthesis of maleimide compound A-11 The same procedure as in the synthesis method of the intermediate amine compound A-1 was carried out except that the reaction time at 210°C was changed to 9 hours and the reaction time at 220°C was changed to 3 hours. , The synthesis method of the maleimide compound A-1 is the same except that the dehydration reaction under reflux in the maleimidation reaction for the synthesized intermediate amine compound (amine equivalent is 342, softening point is 69 ° C.) is 10 hours. 398.7 g of a product containing maleimide compound A-11 was obtained. In the FD-MS spectrum of this maleimide compound A-11, peaks of M+=560, 718 and 876 were confirmed, corresponding to n=0, 1 and 2, respectively. When the value of the repeating unit number n (based on the number average molecular weight) in the indane skeleton portion in the maleimide A-11 was determined by GPC, the GPC chart is shown in FIG. 8, where n=3.68. The molecular weight distribution (Mw/Mn) was 2.09.

[Synthesis Example 9] Synthesis of maleimide compound A-12 The same procedure as in the synthesis method of the intermediate amine compound A-1 was performed except that the reaction time at 210°C was changed to 9 hours and the reaction time at 220°C was changed to 3 hours. , in the same manner as the synthesis method of the maleimide compound A-1, except that the dehydration reaction under reflux in the maleimidation reaction for the synthesized intermediate amine compound (amine equivalent: 347, softening point: 70°C) is performed for 12 hours. 422.7 g of a product containing maleimide compound A-12 was obtained. In the FD-MS spectrum of this maleimide compound A-12, peaks of M+=560, 718 and 876 were confirmed, corresponding to n=0, 1 and 2, respectively. When the value of the repeating unit number n in the indane skeleton portion of the maleimide A-12 (based on the number average molecular weight) was determined by GPC, the GPC chart is shown in FIG. 9, where n=4.29. The molecular weight distribution (Mw/Mn) was 3.02.

[Examples 1 to 9 and Comparative Example 1]
<Solvent solubility of maleimide>
Maleimides (A-1) to (A-5) and (A-9) to (A-12) obtained in Synthesis Examples 1 to 9, and commercially available maleimide (A-6) for comparison (4, Solubility of 4′-diphenylmethanebismaleimide (“BMI-1000” manufactured by Daiwa Kasei Kogyo Co., Ltd.) in toluene and methyl ethyl ketone (MEK) was evaluated, and the evaluation results are shown in Table 1.
As a method for evaluating solvent solubility, each maleimide obtained in the above Synthesis Examples and Comparative Examples was used, and toluene was added so that the nonvolatile content was 10, 20, 30, 40, 50, 60, and 70% by mass. and a methyl ethyl ketone (MEK) solution were prepared.
Specifically, when the vials containing the maleimides obtained in the above synthesis examples and comparative examples were left at room temperature (25° C.) for 60 days, and uniformly dissolved (insoluble The case where no substance was found was evaluated as ◯, and the case where it was not dissolved (with insoluble matter) was evaluated as x (visual observation). In addition, when the non-volatile matter is 20% by mass or more, it is practically preferable if it can be dissolved in the solvent.

[Examples 10 to 18 and Comparative Examples 2 to 4]
<Preparation of curable resin composition>
Maleimides (A-1) to (A-5) and (A-9) to (A-12) obtained in Synthesis Examples 1 to 9, and maleimide for comparison (A-6) (4,4'- Diphenylmethane bismaleimide, "BMI-1000" manufactured by Daiwa Kasei Kogyo Co., Ltd.), maleimide for comparison (A-7) (bisphenol A diphenyl ether bismaleimide, "BMI-4000" manufactured by Daiwa Kasei Kogyo Co., Ltd.), maleimide for comparison (A -8) (3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide, “BMI-5100” manufactured by Daiwa Kasei Kogyo Co., Ltd.), cyanate ester compound (B-1) (2 , 2-bis (4-cyanatophenyl) propane (manufactured by Tokyo Chemical Industry Co., Ltd.)), curing accelerator (C-1) (tetraphenylphosphonium tetra (methylphenyl) borate (manufactured by Hokko Chemical Industry Co., Ltd.)) It was blended at the ratio shown in Table 2.

<Uniformity of Film Appearance>
In Examples 10, 15 to 18, and Comparative Examples 2 to 4, 14.81 g of methyl ethyl ketone (MEK) was mixed and dissolved in the proportions shown in Table 2 to obtain curable resin compositions. 5 g of each curable resin composition is applied to a release PET film (thickness after drying: 295 μm), dried (heated) at 80 ° C. for 1 hour, and further dried (heated) at 120 ° C. for 1 hour. A film molding was produced, and the appearance of the obtained film molding was visually confirmed. When the film appearance was uniform, it was evaluated as ◯, and when the film appearance was uneven, it was evaluated as x (for example, turbidity, insoluble matter, etc. could be confirmed). Table 3 shows the evaluation results.

<Preparation of cured product (molded product)>
A cured product (molded product) was produced by subjecting the curable resin composition to the following conditions.
Curing conditions: After heating at 200° C. for 2 hours, further heat curing was performed at 250° C. for 2 hours.
Plate thickness of hardened product (molded product) after molding: 2.4 mm
Various physical properties and properties of the obtained cured products of Examples 10 to 18 and Comparative Example 2 were evaluated by the following methods. Table 4 shows the evaluation results.

<Glass transition temperature (Tg)>
A cured product having a thickness of 2.4 mm was cut into a size of 5 mm in width and 54 mm in length, and this was used as a test piece. This test piece was subjected to a viscoelasticity measuring device (DMA: solid viscoelasticity measuring device "DMS6100" manufactured by Hitachi High-Tech Science Co., Ltd., deformation mode: bending at both ends, measurement mode: sinusoidal vibration, frequency 1 Hz, temperature increase rate 3 ° C./min). was evaluated as the glass transition temperature Tg (° C.) at which the elastic modulus change was maximum (the tan δ change rate was the largest). From the viewpoint of heat resistance, the glass transition temperature Tg is preferably 250° C. or higher (higher Tg), more preferably 260° C. or higher.

<Thermal expansion>
A cured product having a thickness of 2.4 mm was cut into a size of 5 mm in width and 5 mm in length, and this was used as a test piece. The thermal expansion coefficient CTE (ppm) in the range of 40 to 60° C. was measured for this test piece using a thermal analysis device ("TMA/SS6100" manufactured by SII Nano Technology Co., Ltd., temperature increase rate 3° C./min). From the viewpoint of heat resistance, prevention of warping, etc., the thermal expansion coefficient is preferably 60 ppm or less, more preferably 55 ppm or less.

<Dielectric properties>
Compliant with JIS-C-6481, using the network analyzer "E8362C" manufactured by Agilent Technologies Co., Ltd., by the cavity resonance method, 1 GHz of the test piece after being stored in a room at 23 ° C and 50% humidity for 24 hours after absolute drying. The dielectric constant and dielectric loss tangent were measured. From the viewpoint of reducing transmission loss as an electronic material, the dielectric constant and the dielectric loss tangent are preferably 2.80 or less, more preferably 2.70 or less. Also, the dielectric loss tangent is preferably 0.0050 or less, more preferably 0.0040 or less.

From the evaluation results in Table 1 above, in Examples 1 to 9, maleimide having an indane skeleton was used, so when a toluene solution was prepared, it could be dissolved even if the nonvolatile content was 20% by mass. When the MEK solution was prepared, it could be dissolved even if the non-volatile content was 50 mass %, and it was confirmed that the solvent solubility was 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 is inferior in solvent solubility.

From the evaluation results in Table 3 above, in Examples 10 and 15 to 18, the film obtained by applying and drying the curable resin composition solution (varnish) containing maleimide having an indane skeleton had a uniform appearance. It was also confirmed that the film can be used for applications such as a build-up film, which particularly requires uniform appearance of the obtained film, and circuit boards (copper-clad laminates, etc.). On the other hand, in Comparative Examples 2 to 4, since a commercially available maleimide having no indane skeleton was used, the appearance of the film was uneven, and it was not suitable for applications such as build-up films and circuit boards (copper-clad laminates, etc.). found to be difficult to use.

Further, from the evaluation results in Table 4 above, in Examples 10 to 18, in addition to the maleimide having an indane skeleton, the use of the cyanate ester compound (B), which also contributes to heat resistance and dielectric properties, caused the glass transition It was also confirmed that the temperature is high, the heat resistance is excellent, the thermal expansion is low, the dielectric constant and the dielectric loss tangent are kept low, and the dielectric properties are excellent. On the other hand, in Comparative Example 2, since the maleimide having an indane skeleton was not used, it was confirmed that the dielectric constant and the dielectric loss tangent could not be kept lower than those of the Examples, and the dielectric properties were also inferior.

The curable resin composition of the present invention can be suitably used for heat-resistant members and electronic members because the cured product thereof has excellent heat resistance and dielectric properties. It can be suitably used for up films, build-up substrates, etc., adhesives and resist materials. Moreover, it can be suitably used as a matrix resin for fiber-reinforced resins, and is suitable as a highly heat-resistant prepreg.

1 is a GPC chart of 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. 2 is a GPC chart of maleimide compound (A-5) obtained in Synthesis Example 5. FIG. 2 is a GPC chart of the maleimide compound (A-9) obtained in Synthesis Example 6. FIG. 2 is a GPC chart of the maleimide compound (A-10) obtained in Synthesis Example 7. FIG. 2 is a GPC chart of the maleimide compound (A-11) obtained in Synthesis Example 8. FIG. 2 is a GPC chart of the maleimide compound (A-12) obtained in Synthesis Example 9. FIG.

Claims (7)

Containing a maleimide (A) having an indane skeleton and a cyanate ester compound (B),
A curable resin composition, wherein the maleimide (A) is represented by the following general formula (1).

(In formula (1), Ra is each independently an alkyl group, alkyloxy group or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group or arylthio group having 6 to 10 carbon atoms, 3 to represents 10 cycloalkyl groups, halogen atoms, nitro groups, hydroxyl groups or mercapto groups, wherein Ra may be the same or different within the same ring, and each Rb independently has 1 to 10 carbon atoms; an alkyl group, an alkyloxy group or an alkylthio group, an aryl group having 6 to 10 carbon atoms, an aryloxy group or an arylthio group, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group or a mercapto group, r is 0 to 3. When r is 2 to 3, Rb may be the same or different in the same ring, n is the average number of repeating units, and is 0.95 to 10.5. indicates a numerical value of 0.) A cured product obtained by subjecting the curable resin composition according to claim 1 to a curing reaction. A prepreg comprising a reinforcing base material and a semi-cured product of the curable resin composition according to claim 1 impregnated in the reinforcing base material. A circuit board obtained by laminating the prepreg according to claim 3 and a copper foil, followed by thermocompression molding. A build-up film comprising the curable resin composition according to claim 1 . A semiconductor sealing material comprising the curable resin composition according to claim 1 . A semiconductor device comprising a cured product obtained by heating and curing the semiconductor sealing material according to claim 6 .

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