WO2024070793A1 - Curable resin composition, resin sheet and cured product - Google Patents

Abstract

The present invention provides a curable resin composition which exhibits good curability, while having high heat resistance and low water absorption characteristics.　This curable resin composition contains (A) a maleimide compound and (B) a compound which has, as a partial structure, a functional group that has a Q value within a specific range and an e value within a specific range, the Q value being the index of the stability of radicals and the e value being the index of the polarity of radicals.

Description

CURABLE RESIN COMPOSITION, RESIN SHEET, AND CURED PRODUCT

In recent years, the required characteristics of laminates that mount electrical and electronic components have become more widespread and sophisticated due to the expansion of fields of use. Conventional semiconductor chips were mainly mounted on metal lead frames, but semiconductor chips with high processing power, such as central processing units (hereafter referred to as CPUs), are increasingly being mounted on laminates made of polymer materials.

In particular, semiconductor packages (hereafter referred to as PKGs) used in smartphones and other devices require thinner PKG substrates to meet the demand for smaller size, thinner thickness, and higher density. However, as the PKG substrate becomes thinner, its rigidity decreases, and defects such as large warping can occur when the PKG is heated during solder mounting to the motherboard (PCB). To reduce this, there is a demand for PKG substrate materials with a high Tg above the solder mounting temperature.

In addition, the development of the fifth-generation communication system "5G" is currently accelerating, and it is expected that even greater capacity and faster communication will be achieved. This will lead to an increasing need for low dielectric tangent materials, with a dielectric tangent of at least 0.005 or less at 10 GHz.

Furthermore, as computerization advances in the automotive field, precision electronic devices are sometimes placed near the engine drive, requiring higher levels of heat and moisture resistance. SiC semiconductors are beginning to be used in trains and air conditioners, and the encapsulation material for semiconductor elements is now required to have extremely high heat resistance, which is no longer possible with conventional epoxy resin encapsulation materials.

In light of this background, polymeric materials that can achieve both high heat resistance and low dielectric properties are being studied. For example, Patent Document 1 proposes a composition containing a maleimide resin and a propenyl group-containing phenolic resin. However, on the other hand, since phenolic hydroxyl groups that do not participate in the reaction remain during the curing reaction, the electrical properties are not sufficient. Patent Document 2 discloses an allyl ether resin in which hydroxyl groups are replaced with allyl groups. However, it has been shown that Claisen rearrangement occurs at 190°C, and at 200°C, which is the molding temperature for general substrates, phenolic hydroxyl groups that do not contribute to the curing reaction are generated, so the electrical properties are not satisfactory. In addition, in both cases, there is a concern that the water absorption properties will deteriorate due to the phenolic hydroxyl groups, which are polar groups, and improvements are desired.

Japanese Patent Application Laid-Open No. 04-359911 International Publication No. 2016/002704

The present invention was made in consideration of the above points, and aims to provide a curable resin composition that has high heat resistance and low water absorption properties.

As a result of intensive research conducted by the inventors to solve the above problems, they discovered that a curable resin composition containing a maleimide compound and a compound having a Q value, which is an index of radical stability, and an e value, which is an index of radical polarity, falling within a specific range has excellent curing properties, and the cured product has excellent heat resistance and low water absorption properties, which led to the completion of the present invention.

That is, the present invention relates to the following [1] to [7]. Note that in the present invention, "(Numerical value 1) to (Numerical value 2)" indicates that the upper and lower limits are included.
[1]
(A) a maleimide compound;
(B) a compound having a Q value of 0 to 1.0 and an e value of −2.0 to 0.7;
A curable resin composition comprising:
[2]
The curable resin composition according to the above item [1], wherein the component (B) is a compound having an aromatic ring in the molecule.
[3]
The curable resin composition according to the above item [1], wherein the component (B) is a compound represented by the following formula (4):

(In formula (4), X represents a functional group having an ethylenically unsaturated double bond or an acetylenically unsaturated triple bond, Ar represents a benzene ring or a naphthalene ring, Y represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and k represents an integer of 1 to 4.)
[4]
The curable resin composition according to the above item [1], wherein the component (A) is a compound represented by the following formula (1):

(In formula (1), X's each independently represent any one of the structures represented by the following formulae (2-a) to (2-c). R represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogenated alkyl group. m represents an integer of 1 to 3, n represents the number of repetitions, and the average value n _ave of n is 1<n _ave <10.)

(In formulas (2-a) to (2-c), * represents a bond to a benzene ring. Each _R2 independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and each q independently represents an integer of 1 to 4.)
[5]
The curable resin composition according to any one of the above items [1] to [4], further comprising a polymerization initiator.
[6]
A resin sheet comprising the curable resin composition according to any one of items [1] to [5] above and a support.
[7]
A cured product of the curable resin composition according to any one of the above items [1] to [5].

The present invention makes it possible to provide a curable resin composition that has excellent curability, high heat resistance, and low water absorption properties, and a cured product thereof.

1 shows a GPC chart of Synthesis Example 1. 1 shows an HPLC chart of Synthesis Example 1. The ¹ H-NMR chart of Synthesis Example 1 is shown below. DMA charts of Example 1 and Comparative Example 1 are shown. The DSC charts of Examples 3 to 5 are shown. The DSC charts of Comparative Examples 3 to 5 are shown.

The curable resin composition of the present invention contains (A) a maleimide compound (hereinafter also referred to as component (A)) and (B) a compound having a Q value of 0 to 1.0 and an e value of -2.0 to 0.7 (hereinafter also referred to as component (B)).

The maleimide compound, which is component (A) of the present invention, refers to a compound having one or more maleimide groups in the molecule. Examples of component (A) include 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene), xylo arylalkyl-type maleimide compounds (Anilix Maleimide, manufactured by Mitsui Fine Chemicals Co., Ltd.), biphenylaralkyl-type maleimide compounds (solidified by distilling off the solvent under reduced pressure from a resin solution containing the maleimide compound (M2) described in Example 4 of JP 2009-001783 A), bisaminocumylbenzene-type maleimides (maleimide compounds described in WO 2020/054601 A and compounds represented by the following formula (3)), maleimide compounds having an indane structure described in Japanese Patent No. 6629692 or WO 2020/217679, MATERIAL STAGE Vol. 18, No. 12, 2019 ``Continued Epoxy Resin CAS Number Story - Hardener CAS Number Memorandum No. 31 Bismaleimide (1)'' and MATERIAL STAGE Vol. 19, No. 2 2019 "Continued Epoxy Resin CAS Number Story - Hardener CAS Number Memorandum No. 32 Bismaleimide (2)" includes maleimide compounds, but is not limited to these. These may be used alone or in combination.

From the viewpoints of solvent solubility, dielectric properties, and heat resistance, the component (A) of the present invention is preferably a maleimide compound having a phenylmaleimide structure, and more preferably represented by the following formula (1).

In formula (1), X each independently represents any one of the structures represented by the following formulae (2-a) to (2-c). R represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogenated alkyl group, and is particularly preferably a hydrogen atom. n is the number of repetitions, and the average value n _ave of n is 1<n _ave <10. The value of n _ave can be calculated from the weight average molecular weight (Mw) determined by measurement of the maleimide resin by gel permeation chromatography (GPC).

In formulae (2-a) to (2-c), * represents a bond to a benzene ring. _R2 each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and is particularly preferably a hydrogen atom. q each independently represents an integer of 1 to 4.

X in the formula (1) is particularly preferably a structure represented by the formula (2-b) above, which can be represented by the following formula (3).

In formula (3), R represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogenated alkyl group, and is particularly preferably a hydrogen atom. n represents the number of repetitions, and the average value n _ave of n is 1<n _ave <10. The value of n _ave can be calculated from the value of the weight average molecular weight (Mw) determined by measurement of the maleimide resin by gel permeation chromatography (GPC).

Component (B) of the present invention is a compound having a Q value of 0 to 1.0 and an e value of -2.0 to 0.7. It is more preferable that the Q value is 0.03 to 0.8, and it is even more preferable that the e value is -2.0 to 0.5.

The Q and e values of the present invention are based on the Q and e theory of Alfrey and Price, and are an empirical, but quantified, expression of the fact that the reactivity in the polymerization reaction of vinyl compounds is determined by the polarizability and resonance effect (and steric factors) of the substituents. These are described in general polymer textbooks such as "Polymer Chemistry" (Kyoritsu Shuppan, edited by Murahashi Shunsuke, pp. 75-77), where the Q and e values of various monomers are determined based on styrene as the standard. The Q value is an index of radical stability; if the Q value is small, the radical becomes unstable and tends to have good reactivity. The e value is an index of radical polarity (electrical bias), and copolymerization is likely to occur when the values of the monomers differ greatly, especially when they are a combination of positive and negative signs.

Component (B) preferably has an aromatic ring in the molecule. Examples of aromatic rings include a benzene ring, a biphenyl ring, a naphthalene ring, an indene ring, a terphenyl ring, an acenaphthylene ring, a fluorene ring, a phenalene ring, a phenanthrene ring, and an anthracene ring. From the viewpoint of Q value and e value, compounds having a benzene ring, a naphthalene ring, or an acenaphthylene ring are particularly preferred because the combination with a maleimide compound improves the curing properties. For example, the e value of phenylmaleimide (a partial structure of aromatic maleimide) is 3.24, and the e value of acenaphthylene is -1.88, and the difference in electron density of the olefin in each functional group is very large, so a high curing promotion effect can be expected.

Furthermore, it is preferable that component (B) is represented by the following formula (4).

(In formula (4), X represents a functional group having an ethylenically unsaturated double bond or an acetylenically unsaturated triple bond, Ar represents a benzene ring or a naphthalene ring, Y represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and k represents an integer of 1 to 4.)

In the formula (4), X is preferably represented by the following formulas (a) to (e), and more preferably has a functional group represented by the following formulas (a) to (c).

(In formulas (a) to (e), * indicates the bonding position with Ar in formula (4). When there are two *, it indicates bonds with two carbons on the benzene ring or naphthalene ring.)

Acenaphthylene is preferred as the compound represented by formula (4). Acenaphthylene refined from coal tar may be used, or it may be synthesized by dehydrogenating acenaphthene or dehydrating 1-acenaphthenol. Commercially available acenaphthylene includes, for example, acenaphthylene from JFE Chemical Corporation.

The content of component (A) is from 1 to 1,000 parts by mass, more preferably from 5 to 500 parts by mass, and even more preferably from 10 to 300 parts by mass, per 100 parts by mass of component (B). Within the above range, alternating copolymerization of the electron-deficient olefin of the maleimide and the electron-rich olefin of component (B) is facilitated, improving curability, and is also preferred from the standpoint of improving heat resistance.

[Cure accelerator]
The curable resin composition of the present invention can also have improved curability by adding a curing accelerator. As the curing accelerator, an anionic curing accelerator that accelerates the curing reaction by generating anions upon irradiation with ultraviolet light or visible light or heating, or a cationic curing accelerator that accelerates the curing reaction by generating cations upon irradiation with ultraviolet light or visible light or heating, is preferred.

Examples of anionic curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; trialkylamines such as triethylamine and tributylamine; 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene; of which 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene are preferred. Other examples include phosphines such as triphenylphosphine; and quaternary ammonium salts such as tetrabutylammonium salts, triisopropylmethylammonium salts, trimethyldecanylammonium salts, cetyltrimethylammonium salts, and hexadecyltrimethylammonium hydroxide, but are not limited to these. These may be used alone or in combination.

Examples of cationic curing accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counter ion of the quaternary salt may be a halogen, an organic acid ion, a hydroxide ion, or the like, but is not limited to organic acid ions and hydroxide ions); transition metal compounds (transition metal salts) such as tin octylate, zinc carboxylate (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), and zinc phosphate ester (zinc octylphosphate, zinc stearylphosphate); but are not limited to these. These may be used alone or in combination.

The amount of the curing accelerator used is 0.01 to 5.0 parts by mass, if the total of components (A) and (B) is 100 parts by mass, as required.

[Inorganic filler]
The curable resin composition of the present invention may contain an inorganic filler. Examples of inorganic fillers include powders such as fused silica, crystalline silica, porous silica, alumina, zircon, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconia, aluminum nitride, graphite, forsterite, steatite, spinel, mullite, titania, talc, clay, iron oxide, asbestos, and glass powder, and inorganic fillers obtained by making these into a spherical or crushed shape, but are not limited thereto. In addition, these may be used alone or in combination.

When obtaining a curable resin composition for semiconductor encapsulation, the inorganic filler is used in an amount of preferably 80 to 92 parts by mass, and more preferably 83 to 90 parts by mass, per 100 parts by mass of the curable resin composition. When obtaining a curable resin composition for use as an interlayer insulating layer forming material, or as a substrate material such as a copper-clad laminate, prepreg, or RCC, the inorganic filler is used in an amount of preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by mass of the curable resin composition.

[Polymerization initiator]
The curable resin composition of the present invention can also improve the curability by adding a polymerization initiator. The polymerization initiator is a compound capable of polymerizing an olefin functional group such as an ethylenically unsaturated bond, and examples of the polymerization initiator include an olefin metathesis polymerization initiator, an anionic polymerization initiator, a cationic polymerization initiator, and a radical polymerization initiator. Among these, it is preferable to use a radical polymerization initiator having curability and moderate stability. The radical polymerization initiator is a compound that generates radicals by irradiation with ultraviolet light or visible light or by heating, and starts a chain polymerization reaction. Examples of radical polymerization initiators that can be used include organic peroxides, azo compounds, and benzopinacoles, and it is preferable to use an organic peroxide because it has little effect on curing temperature control, outgassing suppression, and electrical properties of decomposition products.

The above organic peroxides include, for example, ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as dicumyl peroxide and 1,3-bis-(t-butylperoxyisopropyl)-benzene, peroxyketals such as t-butyl peroxybenzoate and 1,1-di-t-butylperoxycyclohexane, α-cumyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, and t-butyl peroxypivalate. Examples of the peroxycarbonate include, but are not limited to, alkyl peresters such as peroxy-2-ethylhexanoate, t-amylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-amylperoxybenzoate, peroxycarbonates such as di-2-ethylhexylperoxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, t-butylperoxyisopropylcarbonate, and 1,6-bis(t-butylperoxycarbonyloxy)hexane, t-butyl hydroperoxide, cumene hydroperoxide, t-butylperoxyoctoate, and lauroyl peroxide. These may be used alone or in combination. Among the above organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, peroxycarbonates, etc. are preferred, with dialkyl peroxides being more preferred.

Examples of the azo compounds include, but are not limited to, azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2,4-dimethylvaleronitrile), etc. Furthermore, these may be used alone or in combination.

The amount of polymerization initiator added is preferably 0.01 to 5 parts by mass, and particularly preferably 0.01 to 3 parts by mass, per 100 parts by mass of the curable resin composition. If the amount of polymerization initiator used is less than 0.01 parts by mass, there is a risk that the molecular weight will not be sufficiently extended during the polymerization reaction, and if it is more than 5 parts by mass, there is a risk that the dielectric properties such as the dielectric constant and dielectric loss tangent will be impaired.

[Polymerization inhibitor]
The curable resin composition of the present invention may contain a polymerization inhibitor. By containing a polymerization inhibitor, storage stability is improved and the reaction initiation temperature can be controlled. By controlling the reaction initiation temperature, it becomes easy to ensure fluidity, impregnation into glass cloth and the like is not impaired, and B-stage such as prepreg formation is facilitated. If the polymerization reaction proceeds too much during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur.

The polymerization inhibitor may be added when component (A) is synthesized or after synthesis. The amount of polymerization inhibitor used is 0.008 to 1 part by weight, preferably 0.01 to 0.5 parts by weight, per 100 parts by weight of component (A).

Examples of polymerization inhibitors include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based. Furthermore, one type of polymerization inhibitor may be used, or multiple types may be used in combination. Of these, in the present invention, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based inhibitors are preferred.

The above-mentioned phenol-based polymerization inhibitors include, for example, monophenols such as 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, and 2,4-bis[(octylthio)methyl]-o-cresol; -t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 2,2-thio-diethylenebis[3-(3,5- di-t-butyl-4-hydroxyphenyl)propionate], 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, bis(3,5-di-t-butyl-4-hydroxybenzylsulfonate ethyl)calcium and other bisphenols, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t -butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, tocopherol and other polymeric phenols are included, but are not limited to these.

Examples of the sulfur-based polymerization inhibitors include, but are not limited to, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

Examples of the phosphorus-based polymerization inhibitors include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecyl pentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentane tetrayl bis(octadecyl) phosphite, cyclic neopentane tetrayl bi(2,4-di-t-butylphenyl) phosphite, cyclic neopentane tetrayl bi(2,4-di-t-butyl-4-methylphenyl) phosphite, bis[2-t -butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite and other phosphites, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and other oxaphosphaphenanthrene oxides, but are not limited to these.

Examples of the above hindered amine-based polymerization inhibitors include ADK STAB LA-40MP, ADK STAB LA-40Si, ADK STAB LA-402AF, ADK STAB LA-87, DEKA STAB LA-82, DEKA STAB LA-81, ADK STAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-72, ADK STAB LA-68, ADK STAB LA-63P, ADK STAB LA-57, ADK STAB L A-52, Chimassorb 2020FDL, Chimassorb 944FDL, Chimassorb 944LD, Tinuvin 622SF, Tinuvin PA144, Tinuvin 765, Tinuvin 770DF, Tinuvin XT55FB, Tinuvin 111FDL, Tinuvin 783FDL, Tinuvin 791FB, etc., but are not limited to these.

Examples of the nitroso-based polymerization inhibitor include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, ammonium salt of N-nitrosophenylhydroxyamine, (cupferron), etc. Among these, the ammonium salt of N-nitrosophenylhydroxyamine (cupferron) is preferred.

Examples of the nitroxyl radical polymerization inhibitor include, but are not limited to, di-tert-butyl nitroxide, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-acetoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl.

[Flame retardants]
The curable resin composition of the present invention may contain a flame retardant. Examples of the flame retardant include halogen-based flame retardants, inorganic flame retardants (antimony compounds, metal hydroxides, nitrogen compounds, boron compounds, etc.), and phosphorus-based flame retardants. From the viewpoint of achieving halogen-free flame retardancy, phosphorus-based flame retardants are preferred.
The phosphorus-based flame retardant may be of a reactive type or an additive type. Specific examples include phosphoric acid esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylyleneyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylyleneyl phosphate, 1,3-phenylene bis(dixylyleneyl phosphate), 1,4-phenylene bis(dixylyleneyl phosphate), and 4,4'-biphenyl(dixylyleneyl phosphate), phosphanes such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, phosphorus-containing epoxy compounds obtained by reacting epoxy resins with active hydrogen of the phosphanes, red phosphorus, and the like, but are not limited thereto. In addition, these may be used alone or in combination. Of the above-listed substances, phosphates, phosphanes, and phosphorus-containing epoxy compounds are preferred, with 1,3-phenylenebis(dixylilenyl phosphate), 1,4-phenylenebis(dixylilenyl phosphate), 4,4'-biphenyl(dixylilenyl phosphate) and phosphorus-containing epoxy compounds being particularly preferred.
[Flame retardants]
The content of the flame retardant is preferably in the range of 0.1 to 0.6 parts by mass, assuming that the sum of components (A) and (B) is 100 parts by mass. If the content is less than 0.1 part by mass, the flame retardancy may be insufficient, and if the content is more than 0.6 part by mass, the moisture absorption and dielectric properties of the cured product may be adversely affected.

[Light stabilizer]
The curable resin composition of the present invention may contain a light stabilizer. As the light stabilizer, a hindered amine light stabilizer, particularly HALS, etc., is preferable. Examples of HALS include a reaction product of dibutylamine, 1,3,5-triazine, N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, a reaction product of dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], bis(1,2 ,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl) and the like, but are not limited thereto. These may be used alone or in combination.

The content of the light stabilizer is preferably in the range of 0.001 to 0.1 parts by mass, assuming that the sum of components (A) and (B) is 100 parts by mass. If it is less than 0.001 parts by mass, it may be insufficient to exert a light stabilizing effect, and if it is more than 0.1 parts by mass, it may have a negative effect on the moisture absorption and dielectric properties of the cured product.

[Binder resin]
The curable resin composition of the present invention may use a binder resin. Examples of the binder resin include, but are not limited to, butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenol resins, epoxy-NBR resins, and silicone resins. These may be used alone or in combination.

The amount of binder resin used is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product, and is preferably 0.05 to 50 parts by mass, and more preferably 0.05 to 20 parts by mass, if the total of components (A) and (B) is 100 parts by mass, as needed.

[Additive]
The curable resin composition of the present invention may contain additives, such as modified acrylonitrile copolymers, polyethylene, fluororesins, silicone gels, silicone oils, surface treatment agents for fillers such as silane coupling agents, release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

The amount of additive is preferably 1,000 parts by mass or less, and more preferably 700 parts by mass or less, per 100 parts by mass of the curable resin composition.

The curable resin composition of the present invention may further contain epoxy resins, active ester compounds, phenolic resins, polyphenylene ether compounds, amine resins, compounds having ethylenically unsaturated bonds, isocyanate resins, polyamide resins, cyanate ester resins, polyimide resins, polybutadiene and modified products thereof, polystyrene and modified products thereof, etc., which may be used alone or in combination. Of these compounds, it is preferable to contain polyphenylene ether compounds, compounds having ethylenically unsaturated bonds, cyanate ester resins, polybutadiene and modified products thereof, and polystyrene and modified products thereof, in view of the balance of heat resistance, adhesion, and dielectric properties. By containing these compounds, the brittleness of the cured product can be improved and adhesion to metals can be improved, and package cracks can be suppressed during reliability tests such as solder reflow and thermal cycles.

Unless otherwise specified, the amount of the above compounds used is preferably 10 times by mass or less, more preferably 5 times by mass or less, and particularly preferably 3 times by mass or less, relative to the amount of component (A). The preferred lower limit is 0.1 times by mass or more, more preferably 0.25 times by mass or more, and even more preferably 0.5 times by mass or more. By being within the above range, it is possible to take advantage of the effects of the heat resistance and dielectric properties of component (A) while adding the effects of each compound added. The following examples of these components can be used.

[Epoxy resin]
Preferred examples of the epoxy resin are shown below, but the epoxy resin is not limited thereto. The epoxy resin may be liquid or solid, and may be used alone or in combination.

Examples of liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure. Specific examples include "RE310S", "RE410S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "828US", "jER828EL", "825", "828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jE807", "1750" (all manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol Novolac type epoxy resin), "630", "630LSD" (all manufactured by Mitsubishi Chemical Corporation, glycidylamine type epoxy resin), "ZX1059" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester type epoxy resin), "Celloxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin having an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin having a butadiene structure), "ZX1658", "ZX1658GS" (all manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane type epoxy resin), etc. may be used. These may be used alone or in combination of two or more.

Preferred examples of solid epoxy resins include bixylenol type epoxy resins, naphthalene type epoxy resins, naphthalene type tetrafunctional epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol type epoxy resins, biphenyl type epoxy resins, naphthylene ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, and tetraphenylethane type epoxy resins, and examples of such solid epoxy resins include naphthol type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, and biphenyl type epoxy resins. Specific examples include "HP4032H" (manufactured by DIC Corporation, naphthalene type epoxy resin), "HP-4700", and "HP-4710" (all manufactured by DIC Corporation, naphthalene type tetrafunctional epoxy resin), "N-690" (manufactured by DIC Corporation, cresol novolac type epoxy resin), "N-695" (manufactured by DIC Corporation, cresol novolac type epoxy resin), "HP-7200" (manufactured by DIC Corporation, dicyclopentadiene type epoxy resin), "HP-7200", "HP-7200HH", and "HP-7200H" (all manufactured by DIC Corporation, dicyclopentadiene type epoxy resin). epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (all manufactured by DIC Corporation, naphthylene ether type epoxy resin), "EPPN-502H" (manufactured by Nippon Kayaku Co., Ltd., trisphenol type epoxy resin), "NC-7000L", "NC-7300" (all manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl ether type epoxy resin). arylalkyl type epoxy resin), "XD-1000-2L", "XD-1000-L", "XD-1000-H", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "ESN475V" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., naphthol type epoxy resin), "ESN485" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., naphthol novolac type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, bixyl lenol type epoxy resin), "YX-8800" (manufactured by Mitsubishi Chemical Corporation, anthracene type epoxy resin), "PG-100", "CG-500" (manufactured by Osaka Gas Chemicals Co., Ltd., fluorene type epoxy resin), "YL-7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF type epoxy resin), "YL-7800" (manufactured by Mitsubishi Chemical Corporation, fluorene type epoxy resin), "jER1010" (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A type epoxy resin), "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane type epoxy resin), etc. These may be used alone or in combination of two or more.

[Active ester compound]
The active ester compound refers to a compound that contains at least one ester bond in the structure and has an aliphatic chain, an aliphatic ring, or an aromatic ring bonded to both sides of the ester bond. Examples of the active ester compound include compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, and are obtained by a condensation reaction between at least one compound of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one compound of a hydroxy compound or a thiol compound. In particular, from the viewpoint of improving heat resistance, it is preferable to obtain it from a carboxylic acid compound or an acid chloride and a hydroxy compound, and the hydroxy compound is preferably a phenol compound or a naphthol compound. The active ester compound may be used alone or in combination of two or more types.

Examples of the carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

Examples of the acid chlorides include acetyl chloride, acrylic acid chloride, methacrylic acid chloride, malonyl chloride, succinic acid dichloride, diglycolyl chloride, glutaric acid dichloride, suberic acid dichloride, sebacic acid dichloride, adipic acid dichloride, dodecandioyl dichloride, azelaic acid chloride, 2,5-furandicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, and 4,4'-azodibenzoyl dichloride.

The above phenol compounds and naphthol compounds include, for example, hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, phenol novolac, and phenol resins described below. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Preferred specific examples of active ester compounds include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated phenol novolac, active ester compounds containing a benzoylated phenol novolac, the compounds described in Example 2 of WO 2020/095829, and the compounds disclosed in WO 2020/059625. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The dicyclopentadiene-type diphenol structure refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester compounds include, for example, "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L-65TM", and "EXB-8150-65T" (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadiene-type diphenol structure, "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, and "phenolnoxamine" (manufactured by DIC Corporation). Examples of active ester compounds containing acetylated volac include "DC808" (manufactured by Mitsubishi Chemical Corporation), active ester compounds containing benzoylated phenol novolac include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), active ester curing agent that is an acetylated phenol novolac, and "EXB-9050L-62M" (manufactured by DIC Corporation) as an active ester curing agent containing phosphorus atoms.

Regarding the compounding ratio of the active ester compound and the epoxy resin, the ratio (α/β) of the active ester equivalent (α) to the epoxy equivalent (β) is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and even more preferably 0.90 to 1.10. Outside the above range, there is a risk that excess epoxy groups or active ester groups will remain in the system, which may cause deterioration of characteristics in high-temperature storage tests (e.g., 150°C, 1000 hours) or long-term reliability tests under high-temperature and high-humidity conditions (e.g., temperature: 85°C, humidity: 85%).

[Phenol resin]
A phenolic resin is a compound having two or more phenolic hydroxyl groups in a molecule. Examples of the phenolic resin include, but are not limited to, a reaction product of a phenol with an aldehyde, a reaction product of a phenol with a diene compound, a reaction product of a phenol with a ketone, a reaction product of a phenol with a substituted biphenyl, a reaction product of a phenol with a substituted phenyl, a reaction product of a bisphenol with an aldehyde, and the like. These may be used alone or in combination.
Specific examples of the above-mentioned raw materials are given below, but the raw materials are not limited thereto.
<Phenols>
Phenol, alkyl-substituted phenol, aromatic-substituted phenol, hydroquinone, resorcin, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.
<Aldehydes>
Formaldehyde, acetaldehyde, alkyl aldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, and the like.
<Diene Compound>
Dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, and the like.
<Ketones>
Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, fluorenone, etc.
<Substituted biphenyls>
4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl, and the like.
<Substituted phenyls>
1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene and the like.

[Polyphenylene ether compound]
From the viewpoints of heat resistance and electrical properties, the polyphenylene ether compound is preferably a polyphenylene ether compound having an ethylenically unsaturated bond, and more preferably a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure. Commercially available products include SA-9000 (manufactured by SABIC, a polyphenylene ether compound having a methacrylic group) and OPE-2St 1200 (manufactured by Mitsubishi Gas Chemical Company, a polyphenylene ether compound having a styrene structure).
The number average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and more preferably 2000 to 4000. If the molecular weight is less than 500, the heat resistance of the cured product tends to be insufficient. If the molecular weight is more than 5000, the melt viscosity increases and sufficient fluidity cannot be obtained, which tends to lead to molding defects. In addition, the reactivity decreases, the curing reaction takes a long time, and the amount of unreacted material that is not incorporated into the curing system increases, which decreases the glass transition temperature of the cured product and tends to decrease the heat resistance of the cured product.
If the number average molecular weight of the polyphenylene ether compound is 500 to 5000, it is possible to exhibit excellent heat resistance, moldability, etc. while maintaining excellent dielectric properties. The number average molecular weight here can be specifically measured using gel permeation chromatography, etc.

The polyphenylene ether compound may be one obtained by a polymerization reaction, or one obtained by a redistribution reaction of a high molecular weight polyphenylene ether compound having a number average molecular weight of about 10,000 to 30,000. These may also be used as raw materials and reacted with a compound having an ethylenically unsaturated bond, such as methacryl chloride, acrylic chloride, or chloromethylstyrene, to impart radical polymerizability. The polyphenylene ether compound obtained by the redistribution reaction may be obtained, for example, by heating a high molecular weight polyphenylene ether compound in a solvent such as toluene in the presence of a phenolic compound and a radical initiator to cause a redistribution reaction. The polyphenylene ether compound obtained by the redistribution reaction in this way has hydroxyl groups derived from phenolic compounds that contribute to hardening at both ends of the molecular chain, and is therefore preferable in that it can maintain even higher heat resistance, and that functional groups can be introduced at both ends of the molecular chain even after modification with a compound having an ethylenically unsaturated bond. The polyphenylene ether compound obtained by the polymerization reaction is also preferable in that it exhibits excellent fluidity.

In the case of a polyphenylene ether compound obtained by a polymerization reaction, the molecular weight of the polyphenylene ether compound can be adjusted by adjusting the polymerization conditions. In the case of a polyphenylene ether compound obtained by a redistribution reaction, the molecular weight of the obtained polyphenylene ether compound can be adjusted by adjusting the conditions of the redistribution reaction. More specifically, it is possible to adjust the amount of the phenolic compound used in the redistribution reaction. That is, the greater the amount of the phenolic compound, the lower the molecular weight of the obtained polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) or the like can be used as a high molecular weight polyphenylene ether compound that undergoes the redistribution reaction. In addition, the phenolic compound used in the redistribution reaction is not particularly limited, but for example, a multifunctional phenolic compound having two or more phenolic hydroxyl groups in the molecule, such as bisphenol A, phenol novolac, cresol novolac, etc., is preferably used. These may be used alone or in combination of two or more.

The content of the polyphenylene ether compound is not particularly limited, but is preferably 5 to 1000 parts by mass, and more preferably 10 to 750 parts by mass, assuming that the total mass of components (A) and (B) is 100 parts by mass. If the content of the polyphenylene ether compound is in the above range, it is preferable in that not only is the heat resistance excellent, but also a cured product that fully exhibits the excellent dielectric properties of the polyphenylene ether compound can be obtained.

[Amine resin]
The amine resin is a compound having two or more amino groups in the molecule. Examples of the amine resin include diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, aniline novolak (a reaction product of aniline and formalin), N-methylaniline novolak (a reaction product of N-methylaniline and formalin), orthoethylaniline novolak (a reaction product of orthoethylaniline and formalin), a reaction product of 2-methylaniline and formalin, a reaction product of 2,6-diisopropylaniline and formalin, a reaction product of 2,6-diethylaniline and formalin, a reaction product of 2-ethyl-6-ethylaniline and formalin, a reaction product of 2,6-dimethylaniline and formalin, and a reaction product obtained by reacting aniline and xylylene chloride. Examples of the aniline resin include, but are not limited to, the aniline resin disclosed in Japanese Patent No. 6429862, a reaction product of aniline and a substituted biphenyl (4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl, etc.), a reaction product of aniline and a substituted phenyl (1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene, etc.), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, a reaction product of aniline and diisopropenylbenzene, dimer diamine, etc. Furthermore, these may be used alone or in combination.

[Compound containing an ethylenically unsaturated bond]
The compound containing an ethylenically unsaturated bond is a compound having one or more ethylenically unsaturated bonds in the molecule that can be polymerized by heat or light, regardless of whether a polymerization initiator is used or not.
Examples of the compound containing an ethylenically unsaturated bond include, but are not limited to, a reaction product of the phenol resin with an ethylenically unsaturated bond-containing halogen-based compound (chloromethylstyrene, allyl chloride, methallyl chloride, acrylic acid chloride, methacrylic acid chloride, etc.), a reaction product of an ethylenically unsaturated bond-containing phenol (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) with a halogen-based compound (1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuric chloride, etc.), a reaction product of an epoxy resin or alcohol with a (meth)acrylic acid (acrylic acid, methacrylic acid, etc.), and an acid-modified product thereof. In addition, these may be used alone or in combination.

[Isocyanate resin]
An isocyanate resin is a compound having two or more isocyanate groups in the molecule. Examples of the isocyanate resin include aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and naphthalene diisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate, and lysine diisocyanate; polyisocyanates such as one or more biuret forms of isocyanate monomers or isocyanate forms obtained by trimerizing the diisocyanate compounds; and polyisocyanates obtained by a urethanization reaction between the isocyanate compounds and polyol compounds, but are not limited thereto. These may be used alone or in combination.

[Polyamide resin]
Examples of polyamide resins include reaction products of one or more of diamines, diisocyanates, and oxazolines with dicarboxylic acids, reaction products of diamines with acid chlorides, and ring-opening polymers of lactam compounds. These may be used alone or in combination.
Specific examples of the above-mentioned raw materials are given below, but the raw materials are not limited thereto.
<Diamine>
Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl diamino-1,8-diaminooctane, dimer diamine, cyclohexane diamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylylene diamine, norbornane diamine, isophorone diamine, bisaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthalenediamine, diaminodiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane , 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-o-ethylaniline, 4,4'-methylenebis-2-ethyl-6-methylaniline, 4,4'-methylenebis-2,6-diisopropylaniline, 4,4-ethylenedianiline, diaminodiphenyl sulfone, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-amino 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, 9,9-bis(4-aminophenyl)fluorene, 2,7-diaminofluorene, aminobenzylamine, diaminobenzophenone, and the like.
<Diisocyanate>
Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, and the like.
<Dicarboxylic acid>
Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, furandicarboxylic acid, 4,4'-dicarboxydiphenyl ether, and 4,4'-dicarboxydiphenyl sulfide.
<Acid chloride>
Acetyl chloride, acrylic acid chloride, methacrylic acid chloride, malonyl chloride, succinic acid dichloride, diglycolyl chloride, glutaric acid dichloride, suberic acid dichloride, sebacic acid dichloride, adipic acid dichloride, dodecandioyl dichloride, azelaic acid chloride, 2,5-furandicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, 4,4'-azodibenzoyl dichloride, and the like.
<Lactam>
ε-caprolactam, ω-undecanelactam, ω-laurolactam, and the like.

[Polyimide resin]
Examples of polyimide resins include, but are not limited to, reaction products of the diamines and the tetracarboxylic dianhydrides shown below. These may be used alone or in combination.
<Tetracarboxylic acid dianhydride>
4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2 dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonate tetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylidene-4,4'-diphthalic dianhydride, 2,2'-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride Anhydride, thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3 ,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7- Naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrene tetracarboxylic dianhydride, ethylene tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride), cyclopentane tetracarboxylic dianhydride tetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylidene-4,4' -bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, rel-[1S,5 R,6R]-3-oxabicyclo[3,2,1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, ethylene glycol-bis-(3,4-dicarboxylic anhydride phenyl)ether, 4,4'-biphenyl bis(trimellitic acid monoester acid anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, and the like.

[Cyanate ester resin]
The cyanate ester resin is a cyanate ester compound obtained by reacting a phenol resin with a cyanogen halide, and specific examples thereof include dicyanatobenzene, tricyanatobenzene, dicyanatonaphthalene, dicyanatobiphenyl, 2,2'-bis(4-cyanatophenyl)propane, bis(4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanatophenyl)propane, 2,2'-bis(4-cyanatophenyl)ethane, 2,2'-bis(4-cyanatophenyl)hexafluoropropane, bis(4-cyanatophenyl)sulfone, bis(4-cyanatophenyl)thioether, phenol novolac cyanate, and phenol-dicyclopentadiene co-condensates in which the hydroxyl groups have been converted to cyanate groups, but are not limited thereto. These may be used alone or in combination.
Furthermore, the cyanate ester compound, the synthesis method of which is described in JP-A-2005-264154, is particularly preferred as the cyanate ester compound because it has low moisture absorption, excellent flame retardancy, and excellent dielectric properties.
The cyanate ester resin may contain a catalyst such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, or dibutyltin maleate, if necessary, to trimerize the cyanate group to form a sym-triazine ring.

The catalyst is preferably used in an amount of 0.0001 to 0.10 parts by mass, and more preferably 0.00015 to 0.0015 parts by mass, per 100 parts by mass of the cyanate ester resin and the combined mass of components (A) and (B).

[Polybutadiene and its modified products]
The polybutadiene and its modified products are polybutadiene or compounds having a structure derived from polybutadiene in the molecule. The unsaturated bonds in the polybutadiene-derived structure may be partially or entirely converted to single bonds by hydrogenation.
Examples of polybutadiene and modified products thereof include, but are not limited to, polybutadiene, hydroxyl-terminated polybutadiene, (meth)acrylated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, styrene butadiene rubber, and the like. These may be used alone or in combination. Of these, polybutadiene or styrene butadiene rubber is preferred from the viewpoint of dielectric properties. Examples of styrene butadiene rubber (SBR) include RICON-100, RICON-181, RICON-184 (all manufactured by Cray Valley Corporation), 1,2-SBS (manufactured by Nippon Soda Co., Ltd.), and examples of polybutadiene include B-1000, B-2000, B-3000 (all manufactured by Nippon Soda Co., Ltd.). The molecular weight of polybutadiene and styrene butadiene rubber is preferably a weight average molecular weight of 500 to 10,000, more preferably 750 to 7,500, and even more preferably 1,000 to 5,000. Below the lower limit of the above range, the amount of volatilization is large, making it difficult to adjust the solid content during prepreg preparation, and above the upper limit of the above range, the compatibility with other curable resins is deteriorated. In general, in the case of compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimide and polymaleimide, it is difficult to ensure compatibility with low-polarity compounds such as compounds mainly composed of hydrocarbons or compounds composed only of hydrocarbons due to their polarity. On the other hand, component (A) of the present invention is excellent in compatibility with materials having low polarity and low dielectric properties and compounds composed only of hydrocarbons, due to the fact that it is not a skeleton design in which heteroatoms such as oxygen and nitrogen are actively introduced.

[Polystyrene and its modified products]
Polystyrene and modified products thereof are polystyrene or compounds having a structure derived from polystyrene in the molecule.
Examples of polystyrene and modified products thereof include polystyrene, styrene-2-isopropenyl-2-oxazoline copolymers (Epocross RPS-1005, RP-61, both manufactured by Nippon Shokubai Co., Ltd.), SEP (styrene-ethylene-propylene copolymer: Septon 1020, manufactured by Kuraray Co., Ltd.), SEPS (styrene-ethylene-propylene-styrene copolymer: Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, all manufactured by Kuraray Co., Ltd.), SEEPS (styrene-ethylene/ethylene-propylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.), and SEBS (styrene-ethylene-butylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.). Examples of the block copolymer include Septon 8004, Septon 8006, and Septon 8007L, all manufactured by Kuraray Co., Ltd.), SEEPS-OH (a compound having a hydroxyl group at the end of a styrene-ethylene/ethylene propylene-styrene block copolymer: Septon HG252, manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymer: Septon 5125 and Septon 5127, both manufactured by Kuraray Co., Ltd.), hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymer: Hybler 7125F and Hybler 7311F, both manufactured by Kuraray Co., Ltd.), SIBS (styrene-isobutylene-styrene block copolymer: SIBSTAR073T, SIBSTAR102T, and SIBSTAR103T (all manufactured by Kaneka Corporation), and Septon V9827 (manufactured by Kuraray Co., Ltd.)), but are not limited thereto. These may be used alone or in combination. Polystyrene and its modified products are preferably those that do not have unsaturated bonds, since they have higher heat resistance and are less susceptible to oxidation degradation. The weight-average molecular weight of polystyrene and its modified products is not particularly limited as long as it is 10,000 or more, but if it is too large, the compatibility with not only polyphenylene ether compounds but also low molecular weight components with weight-average molecular weights of about 50 to 1,000 and oligomer components with weight-average molecular weights of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability, so it is preferably about 10,000 to 300,000.

The curable resin composition of the present invention can be obtained by preparing the above components in a prescribed ratio, pre-curing at 130-180°C for 30-500 seconds, and then post-curing at 150-200°C for 2-15 hours, allowing the curing reaction to proceed sufficiently to obtain the cured product of the present invention. The components of the curable resin composition can also be uniformly dispersed or dissolved in a solvent, etc., and cured after removing the solvent.

The method for preparing the curable resin composition of the present invention is not particularly limited, but each component may be mixed uniformly or may be prepolymerized. For example, a mixture of component (A) and component (B) is prepolymerized by heating in the presence or absence of a curing accelerator or polymerization initiator, and in the presence or absence of a solvent. Similarly, amine compounds, compounds having ethylenically unsaturated bonds, maleimide compounds, cyanate ester compounds, polybutadiene and its modified products, polystyrene and its modified products, inorganic fillers, and other additives may be added to form a prepolymer. The components may be mixed or prepolymerized using, for example, an extruder, kneader, rolls, etc. in the absence of a solvent, and a reaction kettle with a stirrer, etc. in the presence of a solvent.

As a method of uniform mixing, the mixture is kneaded at a temperature in the range of 50 to 100°C using a device such as a kneader, roll, or planetary mixer to obtain a uniform resin composition. The obtained resin composition is crushed and then molded into a cylindrical tablet using a molding machine such as a tablet machine, or into a granular powder or powder molded body, or these compositions can be melted on a surface support and molded into a sheet having a thickness of 0.05 mm to 10 mm to obtain a molded curable resin composition. The obtained molded body is a non-sticky molded body at 0 to 20°C, and even if stored at -25 to 0°C for one week or more, the flowability and curability are hardly reduced.
The obtained molded article can be molded into a cured product using a transfer molding machine or a compression molding machine.

The curable resin composition of the present invention can be made into a varnish-like composition (hereinafter, simply referred to as varnish) by adding an organic solvent. The curable resin composition of the present invention can be dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. as necessary to make a varnish, which can be impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc., and dried by heating to obtain a prepreg, which can be hot-press molded to obtain a cured product of the curable resin composition of the present invention. The solvent used in this case is in an amount that occupies 10 to 70% by weight, preferably 15 to 70% by weight, of the mixture of the curable resin composition of the present invention and the solvent. If the composition is in a liquid state, a curable resin composition containing carbon fiber can be obtained as it is, for example, by the RTM method.

The curable resin composition of the present invention can also be used as a modifier for film-type compositions. Specifically, it can be used to improve flexibility in the B-stage. Such a film-type resin composition can be obtained as a sheet-like adhesive by applying the curable resin composition of the present invention as the curable resin composition varnish onto a release film, removing the solvent under heating, and then performing B-stage conversion. This sheet-like adhesive can be used as an interlayer insulating layer in multilayer substrates, etc.

The curable resin composition of the present invention can be heated and melted to reduce the viscosity, and impregnated into reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers to obtain a prepreg. Specific examples include glass fibers such as E glass cloth, D glass cloth, S glass cloth, Q glass cloth, spherical glass cloth, NE glass cloth, and T glass cloth, as well as inorganic fibers other than glass, and organic fibers such as polyparaphenylene terephthalamide (Kevlar (registered trademark), manufactured by DuPont), fully aromatic polyamide, polyester, polyparaphenylene benzoxazole, polyimide, and carbon fibers, but are not limited to these. The shape of the substrate is not particularly limited, but examples include woven fabric, nonwoven fabric, roving, chopped strand mat, and the like. In addition, plain weave, saddle weave, twill weave, and the like are known as ways of weaving woven fabric, and these known methods can be appropriately selected and used depending on the intended use and performance. In addition, woven fabrics that have been subjected to fiber opening treatment and glass woven fabrics that have been surface-treated with a silane coupling agent or the like are preferably used. The thickness of the substrate is not particularly limited, but is preferably about 0.01 to 0.4 mm. Prepregs can also be obtained by impregnating reinforcing fibers with the varnish and drying them by heating.

Moreover, a laminate can be manufactured using the prepreg. The laminate is not particularly limited as long as it has one or more prepregs, and may have any other layer. The manufacturing method of the laminate can be appropriately applied by a generally known method, and is not particularly limited. For example, when molding a metal foil-clad laminate, a multi-stage press machine, a multi-stage vacuum press machine, a continuous molding machine, an autoclave molding machine, etc. can be used, and the prepregs are laminated together and heated and pressurized to obtain a laminate. At this time, the heating temperature is not particularly limited, but is preferably 65 to 300 ° C, and more preferably 120 to 270 ° C. In addition, the pressure to be applied is not particularly limited, but if the pressure is too high, it is difficult to adjust the solid content of the resin of the laminate, and the quality is not stable, and if the pressure is too low, air bubbles and adhesion between the laminates are deteriorated, so that 2.0 to 5.0 MPa is preferable, and 2.5 to 4.0 MPa is more preferable. The laminate of this embodiment can be suitably used as a metal foil-clad laminate described later by providing a layer made of metal foil.
The prepreg is cut into a desired shape and laminated with copper foil or the like as necessary. The laminate is then heated and cured while applying pressure thereto by press molding, autoclave molding, sheet winding molding or the like, to obtain an electrical and electronic laminate (printed wiring board) or a carbon fiber reinforced material.

The curable resin composition of the present invention can also be made into a resin sheet. A method for obtaining a resin sheet from the curable resin composition of the present invention includes, for example, applying the curable resin composition onto a support film (support), drying the composition, and forming a resin composition layer on the support film. When the curable resin composition of the present invention is used for a resin sheet, it is essential that the film softens under the lamination temperature conditions (70°C to 140°C) in the vacuum lamination method, and exhibits fluidity (resin flow) that allows resin to fill via holes or through holes in the circuit board at the same time as laminating the circuit board, and it is preferable to mix the above-mentioned components so as to exhibit such characteristics. In addition, the obtained resin sheet or circuit board (copper-clad laminate, etc.) is required to have a uniform appearance in order to exhibit a certain performance at any part without causing a phenomenon in which different characteristic values are locally exhibited due to phase separation, etc.

The through holes in the circuit board have a diameter of 0.1 to 0.5 mm and a depth of 0.1 to 1.2 mm, and it is preferable to make it possible to fill them with resin within this range. If both sides of the circuit board are to be laminated, it is desirable to fill about half of the through holes.

A specific method for producing the resin sheet is to prepare a resin composition that has been varnished by blending an organic solvent, and then to apply the varnished resin composition to the surface of a support film (Y), and then to dry the organic solvent by heating or blowing hot air onto the resin composition to form a resin composition layer (X).

The organic solvents used here preferably include, for example, ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetate esters 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, and N-methylpyrrolidone; and it is preferable to use them in a proportion that results in a non-volatile content of 30 to 60% by mass.

The thickness of the resin composition layer (X) formed must be equal to or greater than the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is in the range of 5 to 70 μm, the thickness of the resin composition layer (X) is preferably 10 to 100 μm. The resin composition layer (X) in the present invention may be protected with a protective film, which will be described later. By protecting the resin composition layer with a protective film, it is possible to prevent the adhesion of dirt and the like to the surface of the resin composition layer and prevent scratches.

The support film and protective film may be made of polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate; polycarbonate; polyimide; and even release paper and metal foils such as copper foil and aluminum foil. The support film and protective film may be subjected to a mud treatment, corona treatment, or release treatment. There are no particular limitations on the thickness of the support film, but it is generally in the range of 10 to 150 μm, and preferably 25 to 50 μm. The protective film is preferably made 1 to 40 μm thick.

The support film (Y) is peeled off after laminating it onto the 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 resin sheet has been heat cured, the adhesion of dust and the like during the curing process can be prevented. If the support film is peeled off after curing, a release treatment is applied to the support film beforehand.

A multilayer printed circuit board can be manufactured from the resin sheet obtained as described above. For example, when the resin composition layer (X) is protected by a protective film, the protective film is peeled off, and then the resin composition layer (X) is laminated 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 lamination method may be a batch method or a continuous method using a roll. If necessary, the resin sheet and the circuit board may be heated (preheated) before lamination. The lamination conditions are preferably a pressure bonding temperature (lamination temperature) of 70 to 140°C, a pressure bonding pressure of 1 to 11 kgf/cm ² (9.8×10 ⁴ to 107.9×10 ⁴ N/m ² ), and lamination is preferably performed under reduced pressure of 20 mmHg (26.7 hPa) or less.

The curable resin composition of the present invention can be used to manufacture semiconductor devices. Examples of semiconductor devices include DIP (dual in-line package), QFP (quad flat package), BGA (ball grid array), CSP (chip size package), SOP (small outline package), TSOP (thin small outline package), TQFP (thin quad flat package), etc.

The curable resin composition of the present invention and its cured product can be used in a wide range of fields. Specifically, they can be used in various applications such as molding materials, adhesives, composite materials, and paints. The cured product of the curable resin composition of the present invention exhibits excellent heat resistance and dielectric properties, and is therefore suitable for use in electrical and electronic components such as encapsulants for semiconductor elements, encapsulants for liquid crystal display elements, encapsulants for organic EL elements, laminates (printed wiring boards, BGA substrates, build-up substrates, etc.), lightweight and high-strength structural composite materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, 3D printing, etc.

The present invention will now be described in more detail with reference to examples. Unless otherwise specified, all parts are by weight. Note that the present invention is not limited to these examples.

Various analytical methods used in the examples are described below.
<Gel Permeation Chromatography (GPC)>
The weight average molecular weight (Mw) and number average molecular weight (Mn) were calculated in terms of polystyrene using a polystyrene standard solution.
GPC: DGU-20A3R, LC-20AD, SIL-20AHT, RID-20A, SPD-20A, CTO-20A, CBM-20A (all manufactured by Shimadzu Corporation)
Column: Shodex KF-603, KF-602x2, KF-601x2)
Eluent for coupling: tetrahydrofuran Flow rate: 0.5 ml/min.
Column temperature: 40°C
Detection: RI (Differential Refraction Detector)

<High Performance Liquid Chromatography (HPLC)>
Column: Inertsil ODS-2 (GL Sciences)
Detector: UV 274 nm
Temperature: 40℃
Eluent: acetonitrile/water Flow rate: 1.0 ml/min
Injection volume: 5 μl (concentration: approx. 10 mg/6 ml)
Gradient program: Acetonitrile/water Start 30/70 Gradient → 100/0 after 28 minutes Hold as is

[Synthesis Example 1]
While purging with nitrogen into a flask equipped with a thermometer, a cooling tube, a fractionating tube, and a stirrer, 559 parts of aniline, 291 parts of α,α,α',α'-tetramethylbenzenedimethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 360 parts of toluene, 63 parts of 35% aqueous hydrochloric acid, and stirring were started. The internal temperature was raised to 160°C while removing water generated by dehydration together with toluene, and the reaction was carried out for 15 hours. The mixture was allowed to cool to room temperature, and the removed toluene and water were returned to the system, and 88 parts of 30% aqueous sodium hydroxide solution were added to perform neutralization. Thereafter, the organic layer was washed with water and concentrated until the waste liquid was neutral, and 458 parts of aromatic amine resin (A1) represented by the following formula (5) was obtained. The amine equivalent of the aromatic amine resin (A1) was 185 g/eq, and the softening point was 58.7°C. GPC analysis (RI) showed that n=1 isomers were 61%, and HPLC analysis showed that 4,4'-(1,3-phenylenediisopropylidene)bisaniline in n=1 isomers was 16.7%, so that 4,4'-(1,3-phenylenediisopropylidene)bisaniline in the aromatic amine resin was 10.2%. The GPC chart of the obtained amine resin (A1) is shown in Figure 1, and the HPLC chart is shown in Figure 2. The ¹ H-NMR chart (deuterated chloroform) is shown in Figure 3. A signal derived from an amino group was observed at 3.05-3.65 ppm in the ¹ H-NMR chart.

[Synthesis Example 2]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 147 parts of maleic anhydride, 300 parts of toluene, and 4 parts of methanesulfonic acid, and heated to reflux. Next, a resin solution obtained by dissolving 197 parts of aromatic amine resin (A1) in 95 parts of N-methyl-2-pyrrolidone and 100 parts of toluene was added dropwise over 3 hours while maintaining the reflux state. During this time, the condensed water and toluene that were azeotropically formed under reflux conditions were cooled and separated in the Dean-Stark azeotropic distillation trap, and then the toluene, which was the organic layer, was returned to the system, and the water was discharged outside the system. After the dripping of the resin solution was completed, the reaction was carried out for 6 hours while maintaining the reflux state and performing a dehydration operation.
After the reaction was completed, the mixture was washed with water four times to remove methanesulfonic acid and excess maleic anhydride, and water was removed from the system by azeotropic distillation of toluene and water under reduced pressure at 70°C or less. Then, 2 parts of methanesulfonic acid was added, and the reaction was carried out for 2 hours under heated reflux. After the reaction was completed, the mixture was washed with water four times until the washing water became neutral, and water was removed from the system by azeotropic distillation of toluene and water under reduced pressure at 70°C or less, and toluene was completely distilled off under reduced pressure at 70°C or less to obtain a maleimide resin (M-1). The softening point of the obtained maleimide resin (M-1) was 100°C, and the acid value was 9 mgKOH/g.

[Example 1, Comparative Example 1]
Each material was dissolved in acetone in the proportions shown in Table 1 to a solid content of 70% by mass, mixed, and pre-dried in a vacuum oven at 60°C for 30 minutes, and then pre-dried at 120°C for 30 minutes. 5 g of the obtained powder was used, sandwiched between mirror-finished copper foil (T4X: manufactured by Fukuda Metal Copper Foil Co., Ltd.), vacuum press molded, and cured at 220°C for 2 hours. At this time, a spacer was used in which the center of a cushion paper with a thickness of 250 μm was cut out to 150 mm in length and width. For the evaluation, a test piece was cut to the desired size using a laser cutter as necessary, and the evaluation was performed. The evaluation results are shown in Table 1. DMA charts of Example 1 and Comparative Example 1 are also shown in FIG. 4.

<Heat resistance (DMA)>
Dynamic viscoelasticity measuring instrument: TA-instruments, DMA-2980
Measurement temperature range: -30 to 280°C
Heating rate: 2°C/min Frequency: 10Hz
Test piece size: A piece cut to 5 mm x 50 mm was used (thickness: 0.2 mm)
Tg: The peak point of tan δ (= loss modulus/storage modulus) was defined as Tg. <Water absorption test>
The sample was immersed in water at 25° C. for 24 hours, and the water absorption rate was calculated from the weight difference before and after the water absorption test. The sample size was 5 mm wide x 50 mm long, and the thickness was 0.2 mm.

Acenaphthylene: JFE Chemical Corporation DCP: Dicumyl peroxide (Kayaku Akzo Co., Ltd.)

The results in Table 1 confirm that Example 1 has superior high heat resistance and low water absorption properties compared to the case where the maleimide compound is radically polymerized alone. Also, the results in Figure 4 confirm that Example 1 has superior curability compared to the case where the maleimide compound is cured alone, as no increase in elastic modulus was observed after 300°C due to uncured maleimide groups.

[Example 2, Comparative Example 2]
Each material was dissolved in acetone in the proportions shown in Table 2 to a solid content of 70% by mass, mixed, and pre-dried in a vacuum oven at 60°C for 30 minutes, and then pre-dried at 120°C for 30 minutes. 5 g of the obtained powder was used and vacuum press molded while sandwiching it between mirror-finished copper foil (T4X: manufactured by Fukuda Metal Copper Foil Co., Ltd.), and cured at 220°C for 2 hours. At this time, a spacer was used in which the center of a 250 μm-thick cushion paper was cut out to 150 mm in length and width. For evaluation, a test piece was cut to the desired size using a laser cutter as necessary, and evaluation was performed. The evaluation results are shown in Table 1.

<Dielectric constant test/dielectric tangent test>
The test was performed by a cavity resonator perturbation method using a 10 GHz cavity resonator manufactured by ATE Co., Ltd. The sample size was 1.7 mm wide x 100 mm long, and the thickness was 0.1 mm.

<Heat resistance (DMA)>
Dynamic viscoelasticity measuring instrument: TA-instruments, DMA-2980
Measurement temperature range: -30 to 280°C
Heating rate: 2°C/min Frequency: 10Hz
Test piece size: A piece cut to 5 mm x 50 mm was used (thickness: 0.1 mm)
Tg: The peak point of tan δ (= loss modulus/storage modulus) was defined as Tg.

Acenaphthylene: JFE Chemical Corporation DCP: Dicumyl peroxide (Kayaku Akzo Co., Ltd.)
NC-3000L: Biphenyl aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.)
PN(H-1): Phenol novolac resin (manufactured by Meiwa Kasei Co., Ltd.)
TPP: Triphenylphosphine (Tokyo Chemical Industry Co., Ltd.)

The results in Table 2 confirm that Example 2 has superior heat resistance and low dielectric properties compared to conventionally used epoxy resin compositions.

[Examples 3 to 6, Comparative Examples 3 to 6]
After mixing the materials in the ratios shown in Table 3, curability was evaluated by DSC. The evaluation results and the Q and e values of each compound are shown in Table 3. The Q and e values of the maleimide compound (M-1) are the values of phenylmaleimide, which is a partial structure of the maleimide compound (M-1).
The DSC charts of Examples 3 to 5 are shown in FIG. 5, and the DSC charts of Comparative Examples 3 to 5 are shown in FIG.

<Curability (DSC)>
Differential scanning calorimeter: DSC6220 (manufactured by SII NanoTechnology, Inc.)
Measurement temperature range: 30 to 330°C
Heating rate: 10° C./min. Atmosphere: Nitrogen (30 mL/min)
Sample amount: 5 mg

Acenaphthylene: JFE Chemical Corporation Allylbenzene: Tokyo Chemical Industry Co., Ltd. Ethynylbenzene: Tokyo Chemical Industry Co., Ltd. Butyl acrylate: Tokyo Chemical Industry Co., Ltd. Benzyl acrylate: Tokyo Chemical Industry Co., Ltd.

The results in Table 3 confirm that Examples 3 to 5 have an increased heat release and better curing properties compared to Comparative Example 3, which is a maleimide-only curing system. Comparative Examples 4 and 5 have two peaks, confirming that the alternating copolymerization between components (A) and (B) is not going well.

The curable resin composition, resin sheet and cured product thereof of the present invention are suitably used for electric and electronic parts such as semiconductor encapsulants, printed wiring boards and build-up laminates.

Claims (7)

1. (A) a maleimide compound;
   (B) a compound having a Q value of 0 to 1.0 and an e value of −2.0 to 0.7;
   A curable resin composition comprising:
2. The curable resin composition according to claim 1, wherein component (B) is a compound having an aromatic ring in the molecule.
3. The curable resin composition according to claim 1 , wherein the component (B) is a compound represented by the following formula (4):
   (In formula (4), X represents a functional group having an ethylenically unsaturated double bond or an acetylenically unsaturated triple bond, Ar represents a benzene ring or a naphthalene ring, Y represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and k represents an integer of 1 to 4.)
4. The curable resin composition according to claim 1 , wherein the component (A) is a compound represented by the following formula (1):
   (In formula (1), X's each independently represent any one of the structures represented by the following formulae (2-a) to (2-c). R represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogenated alkyl group. m represents an integer of 1 to 3, n represents the number of repetitions, and the average value n _ave of n is 1<n _ave <10.)
   (In formulas (2-a) to (2-c), * represents a bond to a benzene ring. Each _R2 independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and each q independently represents an integer of 1 to 4.)
5. The curable resin composition according to any one of claims 1 to 4, further comprising a polymerization initiator.
6. A resin sheet comprising the curable resin composition according to claim 5 and a support.
7. A cured product of the curable resin composition according to claim 5.
   
   

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