JP2024156371A - Thermosetting resin composition, cured product, prepreg, resin sheet, metal foil-clad laminate, and printed wiring board - Google Patents

Abstract

[Problem] To provide a thermosetting resin composition, a cured product, a prepreg, a resin sheet, a metal foil-clad laminate, and a printed wiring board that are excellent in balance of heat resistance, low thermal expansion, and interlayer adhesion. [Solution] A thermosetting resin composition containing a polymer E containing a structural unit derived from an alkenylphenol A, a structural unit derived from an epoxy-modified silicone B, and a structural unit derived from an epoxy compound C different from the epoxy-modified silicone B, and an aluminum chelate complex D. [Selected Figure] None

Description

The present invention relates to a thermosetting resin composition, a cured product, a prepreg, a resin sheet, a metal foil-clad laminate, and a printed wiring board.

In recent years, as semiconductor packages, which are widely used in electronic devices, communication devices, personal computers, etc., have become more functional and smaller, the integration and high-density mounting of each component for semiconductor packages has been accelerating in recent years. Accordingly, the properties required for printed wiring boards for semiconductor packages have become increasingly strict, and various studies have been conducted to improve the properties of materials used therein. Against this background, Patent Document 1 proposes applying a curable composition containing an alkenylphenol, an epoxy-modified silicone, and an epoxy compound other than the epoxy-modified silicone, or a curable composition containing a polymer having these as constituent units, to prepregs, resin sheets, metal foil-clad laminates, and printed wiring boards.

International Publication No. 2020/022084

Not only is there a demand for higher heat resistance for semiconductor package laminates, but there is also an increasing demand for a reduction in the thermal expansion coefficient (hereinafter, also simply referred to as "thermal expansion coefficient") in the plane direction of the laminate (hereinafter, a low thermal expansion coefficient is also referred to as "excellent low thermal expansion"). The thermosetting resin composition described in Patent Document 1 can be said to meet these demands in that it achieves both heat resistance and low thermal expansion. Meanwhile, in the thermosetting resin composition described in Patent Document 1, an epoxy-modified silicone compound and/or a reaction product thereof with other components is blended from the viewpoint of low thermal expansion. However, for example, when this is applied to semiconductor package laminates (as an insulating layer disposed on glass), it tends to be difficult to increase the adhesion between the insulating layer and glass (hereinafter, also referred to as "interlayer adhesion") due to the epoxy-modified silicone structure.
As described above, the technique described in Patent Document 1 still has room for improvement in terms of heat resistance, low thermal expansion, and interlayer adhesion.

The present invention has been made in view of the above, and aims to provide a thermosetting resin composition, a cured product, a prepreg, a resin sheet, a metal foil-clad laminate, and a printed wiring board that have an excellent balance of heat resistance, low thermal expansion, and interlayer adhesion.

The present inventors conducted extensive research to solve the above problems. As a result, they discovered that the above problems could be solved by a thermosetting resin composition containing specific components, and thus completed the present invention.

That is, the present invention is as follows.
[1]
a polymer E containing a structural unit derived from an alkenylphenol A, a structural unit derived from an epoxy-modified silicone B, and a structural unit derived from an epoxy compound C different from the epoxy-modified silicone B;
Aluminum chelate complex D;
A thermosetting resin composition comprising:
[2]
The thermosetting resin composition according to [1], wherein a ligand of the aluminum chelate complex D is a bidentate ligand.
[3]
The thermosetting resin composition according to [1] or [2], wherein a ligand of the aluminum chelate complex D contains acetylacetone, an acetylacetone derivative, and/or an alkyl acetoacetate ester.
[4]
The thermosetting resin composition according to any one of [1] to [3], wherein the alkenylphenol A contains diallyl bisphenol and/or dipropenyl bisphenol.
[5]
The thermosetting resin composition according to any one of [1] to [4], wherein the epoxy-modified silicone B contains an epoxy-modified silicone B1 having an epoxy equivalent of 140 to 250 g/mol.
[6]
The thermosetting resin composition according to any one of [1] to [5], wherein the content of the structural unit derived from the epoxy-modified silicone B is 20 to 60 mass% relative to the total mass of the polymer E.
[7]
The thermosetting resin composition according to any one of [1] to [6], wherein the weight average molecular weight of the polymer E is 3.0×10 ³ to 5.0×10 ^{4 .}
[8]
The thermosetting resin composition according to any one of [1] to [7], further comprising a maleimide compound F1 and/or a cyanate ester compound F2.
[9]
The thermosetting resin composition according to any one of [1] to [8], wherein the content of the aluminum chelate complex D is 0.05 to 3 parts by mass per 100 parts by mass of a total of resin solids contained in the thermosetting resin composition.
[10]
The content of the polymer E is 5 to 50 parts by mass per 100 parts by mass of the total resin solid content contained in the thermosetting resin composition. [1] The thermosetting resin composition according to any one of [9] to [10].
[11]
The thermosetting resin composition according to any one of [1] to [10], further comprising an inorganic filler.
[12]
Alkenylphenol A,
Epoxy-modified silicone B;
an epoxy compound C different from the epoxy-modified silicone B;
Aluminum chelate complex D;
A thermosetting resin composition comprising:
[13]
The thermosetting resin composition according to [12], wherein the epoxy compound C contains a naphthalene cresol novolac type epoxy resin and/or a naphthylene ether type epoxy resin.
[14]
A cured product obtained by curing the thermosetting resin composition according to any one of [1] to [13].
[15]
A substrate;
The thermosetting resin composition according to any one of [1] to [13], which is impregnated into or applied to the substrate;
A prepreg comprising:
[16]
A resin sheet comprising the thermosetting resin composition according to any one of [1] to [13].
[17]
A laminate comprising the prepreg according to [15] and/or a cured product obtained by curing the prepreg;
A metal foil disposed on one or both sides of the laminate;
A metal foil-clad laminate comprising:
[18]
[15] An insulating layer comprising a cured product obtained by curing the prepreg according to [15];
A conductor layer formed on a surface of the insulating layer;
A printed wiring board comprising:

The present invention provides a thermosetting resin composition, a cured product, a prepreg, a resin sheet, a metal foil-clad laminate, and a printed wiring board that have an excellent balance of heat resistance, low thermal expansion, and interlayer adhesion.

The following describes in detail the form for carrying out the present invention (hereinafter, referred to as the "present embodiment"). The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out with appropriate modifications within the scope of its gist.

In this embodiment, unless otherwise specified, the "resin solid content" or the "resin solid content in a resin composition" means the resin components in the resin composition excluding the aluminum chelate complex D, the polymerization catalyst G, the aromatic phosphorus compound P, the inorganic filler, the silane coupling agent, the wetting and dispersing agent, the solvent, the curing accelerator, and other components H.
In addition, "100 parts by mass in total of resin solid contents" means that the total of resin components in the resin composition excluding the aluminum chelate complex D, the polymerization catalyst G, the aromatic phosphorus compound P, the inorganic filler, the silane coupling agent, the wetting and dispersing agent, the solvent, the curing accelerator, and other components H is 100 parts by mass.

[Thermosetting resin composition]
The thermosetting resin composition according to the first aspect of the present embodiment (hereinafter also referred to as the “first composition”) comprises an alkenylphenol A, an epoxy-modified silicone B, and The first composition contains a different epoxy compound C and an aluminum chelate complex D. Since the first composition has such a configuration, it has an excellent balance of heat resistance, low thermal expansion property, and interlayer adhesion.
The thermosetting resin composition according to the second aspect of the present embodiment (hereinafter also referred to as the “second composition”) comprises a constitutional unit derived from an alkenylphenol A and a constitutional unit derived from an epoxy-modified silicone B. The second composition contains a polymer E containing a structural unit derived from an epoxy compound C different from the epoxy-modified silicone B, and an aluminum chelate complex D. This provides an excellent balance of heat resistance, low thermal expansion, and interlayer adhesion.
The second composition is distinguished from the first composition in that the presence of polymer E is identified in the second composition.
Hereinafter, when referring to the "thermosetting resin composition of the present embodiment," this includes both the "first composition" and the "second composition," unless otherwise specified.

[Alkenylphenol A]
The alkenylphenol A is not particularly limited as long as it is a compound having a structure in which one or more alkenyl groups are directly bonded to a phenolic aromatic ring. By including the alkenylphenol A, the thermosetting resin composition of the present embodiment has an improved balance between heat resistance and low thermal expansion.

The alkenyl group is not particularly limited, but examples thereof include alkenyl groups having 2 to 30 carbon atoms, such as vinyl groups, allyl groups, propenyl groups, butenyl groups, and hexenyl groups. In particular, from the viewpoint of more effectively and reliably achieving the effects of this embodiment, the alkenyl group is preferably an allyl group and/or a propenyl group, and more preferably an allyl group. The number of alkenyl groups directly bonded to one phenolic aromatic ring is not particularly limited, and is, for example, 1 to 4. From the viewpoint of more effectively and reliably achieving the effects of this embodiment, the number of alkenyl groups directly bonded to one phenolic aromatic ring is preferably 1 to 2, and more preferably 1. In addition, the bonding position of the alkenyl group to the phenolic aromatic ring is not particularly limited, but is preferably the ortho position (2nd and 6th positions).

A phenolic aromatic ring refers to an aromatic ring having one or more hydroxyl groups directly bonded thereto, such as a phenol ring or naphthol ring. The number of hydroxyl groups directly bonded to one phenolic aromatic ring is not particularly limited, and may be, for example, 1 to 2, and preferably 1.

The phenolic aromatic ring may have a substituent other than an alkenyl group. Examples of such a substituent include a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, a linear alkoxy group having 1 to 10 carbon atoms, a branched alkoxy group having 3 to 10 carbon atoms, a cyclic alkoxy group having 3 to 10 carbon atoms, and a halogen atom. When the phenolic aromatic ring has a substituent other than an alkenyl group, the number of the substituents directly bonded to one phenolic aromatic ring is not particularly limited, and is, for example, 1 to 2. In addition, the bonding position of the substituent to the phenolic aromatic ring is also not particularly limited.

Alkenylphenol A may have one or more structures in which one or more alkenyl groups are directly bonded to a phenolic aromatic ring. From the viewpoint of further improving the balance between heat resistance and low thermal expansion, alkenylphenol A preferably has one or two structures in which one or more alkenyl groups are directly bonded to a phenolic aromatic ring, and more preferably has two structures.

The alkenylphenol A may be, for example, a compound represented by the following formula (1A) or the following formula (1B).
(In formula (1A), each Rxa independently represents an alkenyl group having 2 to 8 carbon atoms, each Rxb independently represents an alkyl group having 1 to 10 carbon atoms or a hydrogen atom, each Rxc independently represents an aromatic ring having 4 to 12 carbon atoms, Rxc may form a condensed structure with a benzene ring, Rxc may or may not be present, A represents an alkylene group having 1 to 6 carbon atoms, an aralkylene group having 7 to 16 carbon atoms, an arylene group having 6 to 10 carbon atoms, a fluorenylidene group, a sulfonyl group, an oxygen atom, a sulfur atom or a direct bond (single bond), and when Rxc is not present, one benzene ring may have two or more Rxa and/or Rxb groups.)
(In formula (1B), each Rxd independently represents an alkenyl group having 2 to 8 carbon atoms, each Rxe independently represents an alkyl group having 1 to 10 carbon atoms or a hydrogen atom, Rxf represents an aromatic ring having 4 to 12 carbon atoms, Rxf may form a condensed structure with a benzene ring, Rxf may or may not be present, and when Rxf is not present, one benzene ring may have two or more Rxd and/or Rxe groups.)

In formula (1A) and formula (1B), the alkenyl group having 2 to 8 carbon atoms represented by Rxa and Rxd is not particularly limited, but examples thereof include a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group.

In the formulas (1A) and (1B), when the groups represented by Rxc and Rxf form a condensed structure with a benzene ring, for example, a compound containing a naphthol ring as the phenolic aromatic ring can be mentioned. In addition, in the formulas (1A) and (1B), when the groups represented by Rxc and Rxf do not exist, for example, a compound containing a phenol ring as the phenolic aromatic ring can be mentioned.

In formula (1A) and formula (1B), the alkyl group having 1 to 10 carbon atoms represented by Rxb and Rxe is not particularly limited, but examples thereof include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexyl groups, and branched alkyl groups such as isopropyl, isobutyl, and tert-butyl groups.

In formula (1A), the alkylene group having 1 to 6 carbon atoms represented by A is not particularly limited, and examples thereof include a methylene group, an ethylene group, a trimethylene group, and a propylene group. The aralkylene group having 7 to 16 carbon atoms represented by A is not particularly limited, and examples thereof include a group represented by the formula: -CH ₂ -Ar-CH ₂ -, -CH ₂ -CH ₂ -Ar-CH ₂ -CH ₂ -, or the formula: -CH ₂ -Ar-CH ₂ -CH ₂ - (wherein Ar represents a phenylene group, a naphthylene group, or a biphenylene group). The arylene group having 6 to 10 carbon atoms represented by A is not particularly limited, and examples thereof include a phenylene ring.

In order to more effectively and reliably achieve the effect of this embodiment, it is preferable that Rxf in the compound represented by formula (1B) is a benzene ring (a compound containing a dihydroxynaphthalene skeleton).

From the viewpoint of further improving the balance between heat resistance and low thermal expansion, the alkenyl phenol A is preferably an alkenyl bisphenol in which one alkenyl group is bonded to each of the two phenolic aromatic rings of the bisphenol. From the same viewpoint, the alkenyl bisphenol is preferably a diallyl bisphenol in which one allyl group is bonded to each of the two phenolic aromatic rings of the bisphenol and/or a dipropenyl bisphenol in which one propenyl group is bonded to each of the two phenolic aromatic rings of the bisphenol.

The diallyl bisphenol is not particularly limited, but examples thereof include o,o'-diallyl bisphenol A ("DABPA" manufactured by Daiwa Kasei Kogyo Co., Ltd.), o,o'-diallyl bisphenol F, o,o'-diallyl bisphenol S, and o,o'-diallyl bisphenol fluorene. The dipropenyl bisphenol is not particularly limited, but examples thereof include o,o'-dipropenyl bisphenol A ("PBA01" manufactured by Gun-ei Chemical Industry Co., Ltd.), o,o'-dipropenyl bisphenol F, o,o'-dipropenyl bisphenol S, and o,o'-dipropenyl bisphenol fluorene.

From the viewpoint of more effectively and reliably achieving the effects of the present embodiment, the average number of phenol groups per molecule of alkenylphenol A is preferably 1 or more and less than 3, and more preferably 1.5 or more and 2.5 or less. The average number of phenol groups is calculated by the following formula.

In the above formula, Ai represents the number of phenol groups in an alkenylphenol having i phenol groups in the molecule, Xi represents the proportion of an alkenylphenol having i phenol groups in the molecule to all alkenylphenols, and X ₁ +X ₂ + . . . X _n =1.

[Epoxy-modified silicone B]
The epoxy-modified silicone B is not particularly limited as long as it is a silicone compound or resin modified with an epoxy group-containing group. By containing the epoxy-modified silicone B, the thermosetting resin composition of the present embodiment has low thermal expansion properties and excellent chemical resistance.

The silicone compound or resin is not particularly limited as long as it is a compound having a polysiloxane skeleton in which siloxane bonds are repeatedly formed. The polysiloxane skeleton may be a straight-chain skeleton, a cyclic skeleton, or a mesh-like skeleton. Among these, a straight-chain skeleton is preferable from the viewpoint of more effectively and reliably achieving the effects of the present embodiment.

The epoxy group-containing group is not particularly limited, but examples thereof include a group represented by the following formula (a1).
(In formula (a1), ^R0 represents a single bond, an alkylene group (for example, an alkylene group having 1 to 5 carbon atoms, such as a methylene group, an ethylene group, or a propylene group), an arylene group, or an aralkylene group, and X represents a monovalent group represented by the following formula (a2) or a monovalent group represented by the following formula (a3).)

The epoxy-modified silicone B preferably contains epoxy-modified silicone B1 having an epoxy equivalent of 140 to 250 g/mol. By containing epoxy-modified silicone B1 having an epoxy equivalent within the above range, the epoxy-modified silicone B tends to further improve the balance between heat resistance and low thermal expansion. From the same viewpoint, the epoxy equivalent is more preferably 145 to 245 g/mol, and even more preferably 150 to 240 g/mol.

From the viewpoint of further improving the balance between heat resistance and low thermal expansion, it is preferable that the epoxy-modified silicone B contains two or more kinds of epoxy-modified silicones. In this case, it is preferable that the two or more kinds of epoxy-modified silicones each have a different epoxy equivalent, and it is more preferable to contain an epoxy-modified silicone having an epoxy equivalent of 50 to 350 g/mol (hereinafter also referred to as "low equivalent epoxy-modified silicone B1") and an epoxy-modified silicone having an epoxy equivalent of 400 to 4000 g/mol (hereinafter also referred to as "high equivalent epoxy-modified silicone B2"), and it is even more preferable to contain an epoxy-modified silicone having an epoxy equivalent of 140 to 250 g/mol (low equivalent epoxy-modified silicone B1') and an epoxy-modified silicone having an epoxy equivalent of 450 to 3000 g/mol (high equivalent epoxy-modified silicone B2').

When the epoxy-modified silicone B contains two or more kinds of epoxy-modified silicones, the average epoxy equivalent of the epoxy-modified silicone B is preferably 140 to 3000 g/mol, more preferably 250 to 2000 g/mol, and even more preferably 300 to 1000 g/mol. The average epoxy equivalent is calculated by the following formula:
(In the above formula, Ei represents the epoxy equivalent of one of the two or more epoxy-modified silicones, Wi represents the proportion of the epoxy-modified silicone in epoxy-modified silicone B, and _W1 + _W2 + ... _Wn = 1.)

From the viewpoint of further improving the balance between heat resistance and low thermal expansion, the epoxy-modified silicone B preferably contains an epoxy-modified silicone represented by the following formula (1).

In formula (1), each R ¹ independently represents a single bond, an alkylene group, an arylene group, or an aralkylene group; each R ² independently represents an alkyl group having 1 to 10 carbon atoms or a phenyl group; and n represents an integer of 0 to 100.

In formula (1), the alkylene group in R ¹ may be linear, branched, or cyclic. The number of carbon atoms in the alkylene group is preferably 1 to 12, and more preferably 1 to 4. Examples of the alkylene group include a methylene group, an ethylene group, and a propylene group. Among these, R ¹ is preferably a propylene group.

In formula (1), the arylene group in R ¹ may have a substituent. The number of carbon atoms in the arylene group is preferably 6 to 40, and more preferably 6 to 20. Examples of the arylene group include a phenylene group, a cyclohexylphenylene group, a hydroxyphenylene group, a cyanophenylene group, a nitrophenylene group, a naphthylylene group, a biphenylene group, an anthrylene group, a pyrenylene group, and a fluorenylene group. These groups may contain an ether bond, a ketone bond, or an ester bond.

In formula (1), the number of carbon atoms in the aralkylene group in R ¹ is preferably 7 to 30, and more preferably 7 to 13. Examples of the aralkylene group include groups represented by the following formula (XI).
(In formula (XI), * represents a bond.)

In formula (1), the group represented by R ¹ may further have a substituent. Examples of the substituent include a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, a linear alkoxy group having 1 to 10 carbon atoms, a branched alkoxy group having 3 to 10 carbon atoms, and a cyclic alkoxy group having 3 to 10 carbon atoms.

Among the above, it is particularly preferable that R ¹ in formula (1) is a propylene group.

In formula (1), R ² each independently represents an alkyl group having 1 to 10 carbon atoms or a phenyl group. The alkyl group and the phenyl group may have a substituent. The alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic. The alkyl group is not particularly limited, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an isopropyl group, an isobutyl group, and a cyclohexyl group. Among these, it is preferable that R ² is a methyl group or a phenyl group.

In formula (1), n represents an integer of 0 or more, for example, 0 to 100. From the viewpoint of further improving the balance between heat resistance and low thermal expansion, n is preferably 50 or less, more preferably 30 or less, and even more preferably 20 or less.

From the viewpoint of further improving the balance between heat resistance and low thermal expansion, it is preferable that epoxy-modified silicone B contains two or more types of epoxy-modified silicone represented by formula (1). In this case, it is preferable that the two or more types of epoxy-modified silicones contained each have a different n, and it is more preferable to contain an epoxy-modified silicone in which n in formula (1) is 1 to 2 and an epoxy-modified silicone in formula (1) in which n is 5 to 20.

From the viewpoint of more effectively and reliably achieving the effects of this embodiment, the average number of epoxy groups per molecule of the epoxy-modified silicone B is preferably from 1 to less than 3, and more preferably from 1.5 to 2.5. The average number of epoxy groups is calculated by the following formula.
(In the above formula, Bi represents the number of epoxy groups in the epoxy-modified silicone having i epoxy groups in the molecule, Yi represents the proportion of the epoxy-modified silicone having i epoxy groups in the molecule in the total epoxy-modified silicone, and _Y1 + _Y2 + ... _Yn = 1.)

From the viewpoint of achieving even better low thermal expansion and chemical resistance, the content of epoxy-modified silicone B is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, even more preferably 40 to 85% by mass, and even more preferably 50 to 80% by mass, relative to 100% by mass of the total of epoxy-modified silicone B and epoxy compound C.

As the epoxy-modified silicone B, a commercially available product may be used, or a product manufactured by a known method may be used. Examples of commercially available products include "X-22-163" and "KF-105" manufactured by Shin-Etsu Chemical Co., Ltd.

[Epoxy compound C]
The epoxy compound C is an epoxy compound other than the epoxy-modified silicone B, and more specifically, is an epoxy compound that does not have a polysiloxane skeleton. By containing the epoxy compound C, the thermosetting resin composition of the present embodiment can exhibit heat resistance, chemical resistance, copper foil adhesion, and insulation reliability.

The epoxy compound C is not particularly limited as long as it is an epoxy compound other than the epoxy-modified silicone B. As the epoxy compound C in the thermosetting resin composition of this embodiment, typically, a bifunctional epoxy compound having two epoxy groups in one molecule or a polyfunctional epoxy compound having three or more epoxy groups in one molecule can be used. From the viewpoint of being able to exhibit even more excellent heat resistance, chemical resistance, copper foil adhesion, and insulation reliability, it is preferable that the epoxy compound C contains a bifunctional epoxy compound and/or a polyfunctional epoxy compound.

The epoxy compound C in the thermosetting resin composition of the present embodiment is not particularly limited, but a compound represented by the following formula (3a) can be used.
In formula (3a), each Ar ³ independently represents a benzene ring or a naphthalene ring; each Ar ⁴ independently represents a benzene ring, a naphthalene ring, or a biphenyl ring; each R ^3a independently represents a hydrogen atom or a methyl group; k represents an integer of 1 to 50;
Here, the benzene ring or naphthalene ring in ^Ar3 may further have one or more substituents, and the substituent may be a glycidyloxy group (not shown) or other substituents such as an alkyl group having 1 to 5 carbon atoms, a phenyl group, etc.
The benzene ring, naphthalene ring or biphenyl ring in ^Ar4 may further have one or more substituents, and the substituent may be a glycidyloxy group or other substituents such as an alkyl group having 1 to 5 carbon atoms, a phenyl group, etc.

Among the compounds represented by the formula (3a), examples of the bifunctional epoxy compounds include compounds represented by the following formula (b1).
In formula (b1), each Ar ³ independently represents a benzene ring or a naphthalene ring; each Ar ⁴ independently represents a benzene ring, a naphthalene ring, or a biphenyl ring; each R ^3a independently represents a hydrogen atom or a methyl group;
Here, the benzene ring or naphthalene ring in ^Ar3 may further have one or more substituents, and the substituent may be, for example, a substituent other than a glycidyloxy group, such as an alkyl group having 1 to 5 carbon atoms or a phenyl group,
The benzene ring, naphthalene ring or biphenyl ring in ^Ar4 may further have one or more substituents, and the substituent may be, for example, a substituent other than a glycidyloxy group, such as an alkyl group having 1 to 5 carbon atoms or a phenyl group.

The compound represented by formula (3a) is preferably a phenol novolac epoxy resin in which Ar ⁴ in formula (3a) is substituted with at least a glycidyloxy group. The phenol novolac epoxy resin is not particularly limited, but examples thereof include a compound having a structure represented by the following formula (3-1) (a naphthalene skeleton-containing polyfunctional epoxy resin having a naphthalene skeleton) and a naphthalene cresol novolac epoxy resin.
(In the formula, each Ar ³¹ independently represents a benzene ring or a naphthalene ring, each Ar ⁴¹ independently represents a benzene ring, a naphthalene ring, or a biphenyl ring, each R ^31a independently represents a hydrogen atom or a methyl group, p represents 1, kz represents an integer from 1 to 50, each ring may have a substituent other than a glycidyloxy group (e.g., an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a phenyl group), and at least one of Ar ³¹ and Ar ⁴¹ represents a naphthalene ring.)

An example of a compound having a structure represented by formula (3-1) is a compound having a structure represented by formula (3-2).
(In the formula, R represents a methyl group, and kz has the same meaning as kz in the above formula (3-1).)

The naphthalene cresol novolac type epoxy resin is not particularly limited, but for example, a cresol/naphthol novolac type epoxy resin represented by the following formula (NE) is preferable. Note that the compound represented by the following formula (NE) is a random copolymer of a cresol novolac epoxy structural unit and a naphthol novolac epoxy structural unit, and both the cresol epoxy and the naphthol epoxy can be terminal.

In the formula (NE), m and n each represent an integer of 1 or more. There are no particular limitations on the upper limit of m and n and their ratio, but from the viewpoint of low thermal expansion, m:n (where m+n=100) is preferably 30-50:70-50, and more preferably 45-55:55-45.

As the naphthalene cresol novolac type epoxy resin, a commercially available product may be used, or a product manufactured by a known method may be used. Examples of commercially available products include "NC-7000", "NC-7300", and "NC-7300L" manufactured by Nippon Kayaku Co., Ltd., and "HP-9540" and "HP-9500" manufactured by DIC Corporation, with "HP-9540" being particularly preferred.

The compound represented by formula (3a) may be a compound other than the above-mentioned phenol novolak type epoxy resin (hereinafter, also referred to as "aralkyl type epoxy resin").
As the aralkyl type epoxy resin, a compound in which ^Ar3 is a naphthalene ring and ^Ar4 is a benzene ring in formula (3a) (also referred to as a "naphthol aralkyl type epoxy resin"), and a compound in which ^Ar3 is a benzene ring and ^Ar4 is a biphenyl ring in formula (3a) (also referred to as a "biphenyl aralkyl type epoxy resin") are preferred, and a biphenyl aralkyl type epoxy resin is more preferred.

As the naphthol aralkyl type epoxy resin, a commercially available product may be used, or a product produced by a known method may be used. Examples of commercially available products include "HP-5000" and "HP-9900" manufactured by DIC Corporation, and "ESN-375" and "ESN-475" manufactured by Nippon Steel Chemical & Material Co., Ltd.

The biphenylaralkyl type epoxy resin is preferably a compound represented by the following formula (3b).
(In the formula, ka represents an integer of 1 or more, preferably 1 to 20, and more preferably 1 to 6.)

Among the compounds represented by the above formula (3b), examples of bifunctional epoxy compounds include compounds in which ka is 1 in formula (3b).

As the biphenyl aralkyl type epoxy resin, a commercially available product may be used, or a product manufactured by a known method may be used. Examples of commercially available products include "NC-3000", "NC-3000L", and "NC-3000FH" manufactured by Nippon Kayaku Co., Ltd.

In addition, as the epoxy compound C in the thermosetting resin composition of this embodiment, it is preferable to use a naphthalene type epoxy resin (excluding those corresponding to the compound represented by formula (3a)). As the naphthalene type epoxy resin, from the viewpoint of further improving heat resistance, chemical resistance, copper foil adhesion, and insulation reliability, it is preferable to use a naphthylene ether type epoxy resin.

From the viewpoint of further improving heat resistance, chemical resistance, copper foil adhesion and insulation reliability, the naphthylene ether type epoxy resin is preferably a bifunctional epoxy compound represented by the following formula (3-3) or a polyfunctional epoxy compound represented by the following formula (3-4), or a mixture thereof.
(In the formula, each R ₁₃ independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms (e.g., a methyl group or an ethyl group), or an alkenyl group having 2 to 3 carbon atoms (e.g., a vinyl group, an allyl group, or a propenyl group).
(In the formula, each R ₁₄ independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms (e.g., a methyl group or an ethyl group), or an alkenyl group having 2 to 3 carbon atoms (e.g., a vinyl group, an allyl group, or a propenyl group).

The naphthylene ether type epoxy resin may be a commercially available product, or a product produced by a known method. Commercially available naphthylene ether type epoxy resins include, for example, DIC Corporation products "HP-6000", "EXA-7300", "EXA-7310", "EXA-7311", "EXA-7311L", "EXA7311-G3", "EXA7311-G4", "EXA-7311G4S", and "EXA-7311G5", with HP-6000 being particularly preferred.

Examples of the naphthalene-type epoxy resin other than those mentioned above include, but are not limited to, the compound represented by the following formula (b3).
(In formula (b3), each R ^3b independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms (e.g., a methyl group or an ethyl group), an aralkyl group, a benzyl group, a naphthyl group, a naphthyl group containing at least one glycidyloxy group, or a naphthylmethyl group containing at least one glycidyloxy group, and n represents an integer of 0 or more (e.g., 0 to 2).)

Commercially available products of the compound represented by formula (b3) include, for example, DIC Corporation products "HP-4032" (in formula (b3) above, n = 0) and "HP-4710" (in formula (b3) above, n = 0, and R ^3b is a naphthylmethyl group containing at least one glycidyloxy group).

As the epoxy compound C in the thermosetting resin composition of the present embodiment, it is preferable to use a biphenyl type epoxy resin (excluding those corresponding to the above-mentioned epoxy compound C).
The biphenyl type epoxy resin is not particularly limited, but examples thereof include a compound represented by the following formula (b2) (compound b2).
(In formula (b2), each Ra independently represents an alkyl group having 1 to 10 carbon atoms or a hydrogen atom.)

In formula (b2), the alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic. The alkyl group is not particularly limited, but examples thereof include methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, and cyclohexyl. The compound represented by formula (b2) is available as a commercially available product, and an example of such a commercially available product is "YL-6121H" manufactured by Mitsubishi Chemical Corporation.

When the biphenyl type epoxy resin is compound b2, the biphenyl type epoxy resin may be in the form of a mixture of compounds b2 having different numbers of alkyl groups Ra. Specifically, it is preferable that the mixture is a biphenyl type epoxy resin having different numbers of alkyl groups Ra, and it is more preferable that the mixture is a compound b2 having 0 alkyl groups Ra and a compound b2 having 4 alkyl groups Ra.

As the epoxy compound C in the thermosetting resin composition of the present embodiment, a dicyclopentadiene type epoxy resin (excluding those corresponding to the above-mentioned epoxy compound C) can be used.
The dicyclopentadiene type epoxy resin is not particularly limited, but examples thereof include the compound represented by the following formula (3-5).
(In the formula, each R ^3c independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and k2 represents an integer of 0 to 10.)

The compound represented by the above formula (3-5) is not particularly limited, and may be, for example, a compound represented by the following formula (b4).
(In formula (b4), each R ^3c independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms (e.g., a methyl group or an ethyl group).)

The dicyclopentadiene type epoxy resin may be a commercially available product, or a product produced by a known method. Commercially available dicyclopentadiene type epoxy resins include "EPICRON HP-7200L", "EPICRON HP-7200", "EPICRON HP-7200H", "EPICRON HP-7000HH" and the like, manufactured by Dainippon Ink and Chemicals, Inc.

Among these, from the viewpoint of achieving even better heat resistance, chemical resistance, copper foil adhesion, and insulation reliability, it is preferable that epoxy compound C is one or more selected from the group consisting of epoxy compounds represented by formula (3a), naphthalene type epoxy resins, and biphenyl type epoxy resins. In this case, it is preferable that the epoxy compound represented by formula (3a) includes a naphthalene cresol novolac type epoxy resin, and the naphthalene type epoxy resin includes a naphthylene ether type epoxy resin. In other words, it is preferable that epoxy compound C includes a naphthalene cresol novolac type epoxy resin and/or a naphthylene ether type epoxy resin.

The epoxy compound C may contain other epoxy compounds other than those mentioned above.
Examples of other epoxy compounds include, but are not limited to, bisphenol-type epoxy resins, trisphenolmethane-type epoxy resins, anthracene-type epoxy resins, glycidyl ester-type epoxy resins, polyol-type epoxy resins, isocyanurate ring-containing epoxy resins, fluorene-type epoxy resins, and epoxy resins composed of bisphenol A-type structural units and hydrocarbon-based structural units.
Among the above, the other epoxy compounds may include bisphenol type epoxy resins from the viewpoint of further improving chemical resistance, copper foil adhesion, and insulation reliability. As the bisphenol type epoxy resin, for example, diallyl bisphenol type epoxy resins (for example, diallyl bisphenol A type epoxy resin, diallyl bisphenol E type epoxy resin, diallyl bisphenol F type epoxy resin, diallyl bisphenol S type epoxy resin, etc.) can be used.

As the epoxy compound C, one of the above-mentioned epoxy compounds and epoxy resins may be used alone or two or more of them may be used in combination.

From the viewpoint of more effectively and reliably achieving the effects of the present embodiment, the average number of epoxy groups per molecule of the epoxy compound C is preferably 1 or more and less than 3, and more preferably 1.5 or more and 2.5 or less. The average number of epoxy groups is calculated by the following formula.
(In the above formula, Ci represents the number of epoxy groups in an epoxy compound having i epoxy groups in a molecule, Zi represents the ratio of the epoxy compound having i epoxy groups in a molecule to the total epoxy compounds, and _Z1 + _Z2 + ... _Zn = 1.)

From the viewpoint of achieving even better heat resistance, chemical resistance, copper foil adhesion, and insulation reliability, the content of epoxy compound C is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, even more preferably 15 to 60% by mass, and particularly preferably 20 to 50% by mass, relative to 100% by mass of the total amount of epoxy-modified silicone B and epoxy compound C.

[Aluminum chelate complex D]
The aluminum chelate complex D is not particularly limited as long as it is a compound having a structure in which a bidentate or higher ligand is coordinated to aluminum (aluminum ion) as a central metal. By containing the aluminum chelate complex D, the thermosetting resin composition of the present embodiment has an improved balance of heat resistance, low thermal expansion, and interlayer adhesion. The reason for this is not necessarily clear, and although it is not intended to limit the reason here, it is presumed to be as follows.
In the thermosetting resin composition of this embodiment, the above-mentioned alkenylphenol A, epoxy-modified silicone B, and epoxy compound C are contained as a mixture capable of reacting with each other and/or in the form of a reactant (polymer E). As described above, when the mixture containing the epoxy-modified silicone B or its reactant is applied to, for example, a laminate for semiconductor packaging, the epoxy-modified silicone structure improves the low thermal expansion, while ingenuity is required from the viewpoint of interlayer adhesion. That is, when the composition containing the above-mentioned mixture and/or reactant is applied, for example, as an insulating layer arranged on glass, the epoxy-modified silicone structure tends to make it difficult to improve adhesion to the glass. Here, the aluminum chelate complex D contained in the thermosetting resin composition of this embodiment can function as a catalyst in the reaction between the epoxy-modified silicone and other thermosetting materials that may be present in the system, but the aluminum chelate complex D tends to take a relatively long time to act compared to existing epoxy curing catalysts, and as a result, it is considered that the epoxy-modified silicone and other thermosetting materials tend to be cured in a state where they are not mixed too much and are separated to a certain extent. By curing in this manner, it is believed that the interlayer adhesion that the thermosetting material may potentially have becomes more apparent, and the interlayer adhesion of the thermosetting resin composition as a whole tends to be improved.
However, the above description merely describes one possible factor by which the thermosetting resin composition of the present embodiment exhibits excellent heat resistance and low thermal expansion without impairing interlayer adhesion, and the mechanism of action of the present embodiment is not limited thereto.

The ligand of the aluminum chelate complex D is not particularly limited, and examples thereof include bidentate ligands such as oxalic acid, quinolinol, acetylacetone, acetylacetone derivatives, and alkyl acetoacetate esters, and tridentate or higher ligands such as phthalocyanine, etc. The aluminum chelate complex D may contain one type of ligand alone or two or more types of ligands in combination.
In this embodiment, the ligand is preferably a bidentate ligand among the above examples, since it is believed that the above-mentioned action tends to be more effectively exerted when the ligand coordinated to the aluminum ion is appropriately dissociated in the reaction system and exists stably as a catalytic intermediate.
In addition, the ligand coordinated to the aluminum ion may dissociate to an appropriate extent in the reaction system and exist as a catalytic intermediate. From the viewpoint of making it easier to control the reaction conditions taking this into account, it is preferable that the aluminum chelate complex D contains only one type of ligand.
Furthermore, it is considered that the above-mentioned action tends to be more effectively exhibited when the ligand coordinated to the aluminum ion is appropriately dissociated in the reaction system and stably exists as a catalytic intermediate, and therefore it is preferable that the ligand in this embodiment contains acetylacetone, an acetylacetone derivative, and/or an alkyl acetoacetate ester among the above examples.
The acetylacetone derivative is not particularly limited as long as it is a derivative in which at least a portion of acetylacetone is substituted. The acetylacetone derivative is not particularly limited, but typically includes a compound represented by H ₃ CC(═O)CH ₂ C(═O)R (wherein R represents an alkyl group having 1 to 5 carbon atoms), and specific examples thereof include, but are not limited to, 2,4-hexanedione. The acetoacetate alkyl ester is not particularly limited as long as it is an alkyl ester of acetoacetate, and examples thereof include methyl acetoacetate, ethyl acetoacetate, and the like.
In order to further improve the balance between heat resistance and interlayer adhesion, the ligand in this embodiment is preferably acetylacetone or ethylacetoacetate, and more preferably ethylacetoacetate.

The content of aluminum chelate complex D in the thermosetting resin composition of the present embodiment is not particularly limited, but from the viewpoint of further improving the balance between heat resistance, low thermal expansion property, and interlayer adhesion, the content is preferably 0.005 to 2 mass%, more preferably 0.012 to 0.6 mass%, and even more preferably 0.025 to 0.25 mass%, relative to 100 mass% of the thermosetting resin composition of the present embodiment.
From the same viewpoint as above, the content of aluminum chelate complex D in the thermosetting resin composition of the present embodiment is preferably 0.05 to 3 parts by mass, more preferably 0.07 to 1 part by mass, and even more preferably 0.1 to 0.5 parts by mass, relative to 100 parts by mass of the total resin solid content.

[Polymer E]
The second composition includes a polymer E containing a structural unit derived from an alkenylphenol A, a structural unit derived from an epoxy-modified silicone B, and a structural unit derived from an epoxy compound C. The polymer E may further contain a structural unit derived from a phenolic compound A' other than the alkenylphenol A. In this specification, the description of "structural unit derived from alkenylphenol A", "structural unit derived from epoxy-modified silicone B", "structural unit derived from epoxy compound C" and "structural unit derived from a phenolic compound A' other than the alkenylphenol A" includes the case where the polymer E contains structural units obtained by polymerizing each component of the alkenylphenol A, the epoxy-modified silicone B, the epoxy compound C, and, if necessary, the phenolic compound A', and the case where the polymer E contains structural units formed by a reaction or the like that can give the same structural unit. The alkenylphenol A, the epoxy-modified silicone B, and the epoxy compound C are as described above. The phenolic compound A' will be described later.
By containing polymer E, the second composition can exhibit even better heat resistance, low thermal expansion property, chemical resistance, copper foil adhesion and insulation reliability.

Hereinafter, the constituent units derived from alkenylphenol A, the constituent units derived from epoxy-modified silicone B, the constituent units derived from epoxy compound C, and the constituent units derived from a phenol compound A' other than alkenylphenol A will also be referred to as constituent units A, B, C, and A', respectively.

In addition to the polymer E and the aluminum chelate complex D, the second composition may further contain, as necessary, at least one compound F selected from the group consisting of a maleimide compound, a cyanate ester compound, a phenol compound A' other than the alkenylphenol A, and an alkenyl-substituted nadiimide compound, which will be described later. The compound F may be an unreacted component remaining after the polymerization of the polymer E, or may be a component added again to the synthesized polymer E.

The second composition may contain at least one selected from the group consisting of the above-mentioned alkenylphenol A, epoxy-modified silicone B, and epoxy compound C, in addition to the polymer E and the aluminum chelate complex D. In this case, the alkenylphenol A, epoxy-modified silicone B, or epoxy compound C contained in the second composition may be an unreacted component remaining after polymerization of the polymer E, or may be a component newly added to the synthesized polymer E.

The weight average molecular weight of polymer E is preferably 3.0×10 ³ to 5.0×10 ⁴ , and more preferably 3.0×10 ³ to 2.0×10 ⁴ , in terms of polystyrene measured by gel permeation chromatography. When the weight average molecular weight is 3.0×10 ³ or more, the second composition tends to exhibit even better copper foil adhesion and chemical resistance. When the weight average molecular weight is 5.0×10 ⁴ or less, the balance between heat resistance and low thermal expansion tends to be further improved.

The content of structural unit A in polymer E is preferably 5 to 50% by mass, based on the total mass of polymer E. When the content of structural unit A is within the above range, the second composition tends to have a further improved balance between heat resistance and low thermal expansion. From the same viewpoint, the content of structural unit A is more preferably 10 to 45% by mass, and even more preferably 10 to 40% by mass.

The content of structural unit B in polymer E is preferably 20 to 60% by mass, based on the total mass of polymer E. By having the content of structural unit B within the above range, the second composition tends to exhibit even better low thermal expansion and chemical resistance in a well-balanced manner. From the same viewpoint, the content of structural unit B is more preferably 25 to 55% by mass, and even more preferably 30 to 55% by mass.

The structural unit B preferably contains a structural unit derived from an epoxy-modified silicone having an epoxy equivalent of 50 to 350 g/mol (low equivalent weight epoxy-modified silicone B1) and an epoxy-modified silicone having an epoxy equivalent of 400 to 4000 g/mol (high equivalent weight epoxy-modified silicone B2). It is more preferable that the low equivalent weight epoxy-modified silicone B1 and the high equivalent weight epoxy-modified silicone B2 are, respectively, an epoxy-modified silicone having an epoxy equivalent of 140 to 250 g/mol (low equivalent weight epoxy-modified silicone B1') and an epoxy-modified silicone having an epoxy equivalent of 450 to 3000 g/mol (high equivalent weight epoxy-modified silicone B2').

The content of structural unit B1 derived from low equivalent weight epoxy-modified silicone B1 in polymer E is preferably 5 to 25 mass % relative to the total mass of polymer E, more preferably 7.5 to 20 mass %, and even more preferably 10 to 17 mass %.

The content of structural unit B2 derived from high equivalent weight epoxy-modified silicone B2 in polymer E is preferably 15 to 55 mass % relative to the total mass of polymer E, more preferably 20 to 52.5 mass %, and even more preferably 25 to 50 mass %.

The mass ratio of the content of structural unit B2 to the content of structural unit B1 is preferably 1.5 to 4, more preferably 1.5 to 3.5, and even more preferably 1.5 to 3.3. When the contents of structural unit B1 and structural unit B2 satisfy the above relationship, copper foil adhesion and chemical resistance tend to be further improved.

The structural unit C in the polymer E is preferably a unit derived from at least one selected from the group consisting of the compound represented by the above formula (b1), the compound represented by the above formula (b2), the compound represented by the above formula (b3), and the compound represented by the above formula (b4). Among these, the structural unit C in the polymer E is more preferably a unit derived from the compound represented by the above formula (b2).

The content of structural unit C in polymer E is preferably 5 to 40% by mass relative to the total mass of polymer E. When the content of structural unit C is within the above range, the second composition tends to exhibit even better heat resistance, chemical resistance, copper foil adhesion, and insulation reliability. From the same viewpoint, the content of structural unit C is preferably 10 to 30% by mass, and more preferably 15 to 25% by mass.

The content of structural unit C is preferably 5 to 95 mass %, more preferably 10 to 90 mass %, even more preferably 15 to 60 mass %, and particularly preferably 20 to 50 mass %, relative to the total mass of structural unit B and structural unit C. When the contents of structural unit B and structural unit C satisfy the above relationship, there is a tendency for the heat resistance, chemical resistance, copper foil adhesion, and insulation reliability to be further improved.

The content of structural unit A' in polymer E is preferably 5 to 30 mass% relative to the total mass of polymer E. By having the content of structural unit A' within the above range, the second composition tends to exhibit even better chemical resistance. From the same viewpoint, the content of structural unit A' is preferably 10 to 27.5 mass% relative to the total mass of polymer E, and more preferably 10 to 25 mass%.

The alkenyl group equivalent in polymer E is preferably 300 to 1500 g/mol. When the alkenyl group equivalent is 300 g/mol or more, the elastic modulus of the cured product of the second composition tends to be further reduced, and as a result, the thermal expansion coefficient of a substrate or the like obtained using the cured product tends to be further reduced. When the alkenyl group equivalent is 1500 g/mol or less, the chemical resistance and insulating reliability of the second composition tend to be further improved. From the same viewpoint, the alkenyl group equivalent is preferably 350 to 1200 g/mol, and more preferably 400 to 1000 g/mol.

The content of polymer E in the second composition is preferably 0.5 to 33 mass%, more preferably 1.7 to 24 mass%, and even more preferably 4 to 20 mass%, relative to 100 mass% of the thermosetting resin composition of this embodiment. When the content is within the above range, the second composition tends to exhibit a good balance of even better heat resistance, low thermal expansion, chemical resistance, copper foil adhesion, and insulation reliability.

The content of polymer E in the second composition is preferably 5 to 50 parts by mass, more preferably 10 to 45 parts by mass, and even more preferably 15 to 40 parts by mass, per 100 parts by mass of the total resin solids. When the content is within the above range, the second composition tends to exhibit a good balance of even better heat resistance, low thermal expansion, chemical resistance, copper foil adhesion, and insulation reliability.

The polymer E can be obtained, for example, by reacting alkenylphenol A, epoxy-modified silicone B, epoxy compound C, and, if necessary, any raw material such as phenol compound A' in the presence of a polymerization catalyst G. The reaction may be carried out in the presence of an organic solvent. More specifically, in the above process, the addition reaction between the epoxy groups of the epoxy-modified silicone B and epoxy compound C and the hydroxyl groups of the alkenylphenol A, and the addition reaction between the hydroxyl groups of the obtained addition reaction product and the epoxy groups of the epoxy-modified silicone B and epoxy compound C proceed, thereby obtaining the polymer E.

The polymerization catalyst G is not particularly limited, and examples thereof include imidazole catalysts and phosphorus-based catalysts. These catalysts may be used alone or in combination of two or more. Among these, imidazole catalysts are preferred.

The imidazole catalyst is not particularly limited, and examples thereof include imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole ("TBZ" manufactured by Shikoku Chemical Industry Co., Ltd.), and 2,4,5-triphenylimidazole ("TPIZ" manufactured by Tokyo Chemical Industry Co., Ltd.). Among these, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole ("TBZ" manufactured by Shikoku Chemical Industry Co., Ltd.) and/or 2,4,5-triphenylimidazole ("TPIZ" manufactured by Tokyo Chemical Industry Co., Ltd.) are preferred from the viewpoint of preventing homopolymerization of the epoxy component.

The amount of polymerization catalyst G (preferably an imidazole catalyst) used is not particularly limited, and is preferably 0.1 to 10 parts by mass per 100 parts by mass of the total amount of alkenylphenol A, epoxy-modified silicone B, epoxy compound C, and phenol compound A'. From the viewpoint of increasing the weight-average molecular weight of polymer E, the amount of polymerization catalyst G used is preferably 0.5 parts by mass or more, and more preferably 4.0 parts by mass or less.

The organic solvent is not particularly limited, and for example, a polar solvent or a non-polar solvent can be used. The polar solvent is not particularly limited, and for example, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; cellosolve-based solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate; ester-based solvents such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, methyl methoxypropionate, and methyl hydroxyisobutyrate; amides such as dimethylacetamide and dimethylformamide. The non-polar solvent is not particularly limited, and for example, aromatic hydrocarbons such as toluene and xylene can be used. These solvents can be used alone or in combination of two or more.

The amount of organic solvent used is not particularly limited, and can be, for example, 50 to 150 parts by mass per 100 parts by mass of the total amount of alkenylphenol A, epoxy-modified silicone B, epoxy compound C, and phenol compound A'.

The reaction temperature is not particularly limited and may be, for example, 100 to 170°C. The reaction time is also not particularly limited and may be, for example, 3 to 8 hours.

After the reaction in this step is completed, polymer E may be separated and purified from the reaction mixture by a conventional method.

[Compound F]
From the viewpoint of further improving the heat resistance, low thermal expansion, chemical resistance and copper foil adhesion, the thermosetting resin composition of the present embodiment preferably further contains at least one compound F selected from the group consisting of a maleimide compound F1, a cyanate ester compound F2, a phenol compound A' other than the alkenylphenol A, and an alkenyl-substituted nadiimide compound, as a compound not corresponding to the above-mentioned components. The compound F is not particularly limited, but is preferably bifunctional or more, and may be polyfunctional having three or more functions. From the viewpoint of further improving the heat resistance, low thermal expansion and interlayer adhesion, the thermosetting resin composition of the present embodiment more preferably further contains a maleimide compound F1 and/or a cyanate ester compound F2.

The content of compound F in the thermosetting resin composition of this embodiment is preferably 10 to 80 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass, per 100 parts by mass of the total resin solids.

From the viewpoints of heat resistance, low thermal expansion, and interlayer adhesion, the second composition preferably further contains compound F in addition to polymer E and aluminum chelate complex D. When the second composition contains polymer E and compound F, the content of polymer E in the second composition is preferably 15 to 75 mass%, more preferably 25 to 65 mass%, and even more preferably 35 to 55 mass%, based on 100 mass% of the total of polymer E and compound F. When the content is within the above range, the second composition tends to exhibit even better heat resistance, low thermal expansion, and interlayer adhesion in a well-balanced manner. From the same viewpoint as above, when the second composition contains polymer E and compound F, the content of compound F in the second composition is preferably 25 to 85 mass%, more preferably 35 to 75 mass%, and even more preferably 45 to 65 mass%, based on 100 mass% of the total of polymer E and compound F.

(Maleimide compound F1)
From the viewpoint of further improving the heat resistance, low thermal expansion property, and chemical resistance, the thermosetting resin composition of the present embodiment preferably contains a maleimide compound F1. The maleimide compound F1 is not particularly limited as long as it is a compound having one or more maleimide groups in one molecule, but examples thereof include monomaleimide compounds having one maleimide group in one molecule (e.g., N-phenylmaleimide, N-hydroxyphenylmaleimide, etc.), polymaleimide compounds having two or more maleimide groups in one molecule (e.g., bis(4-maleimidophenyl)methane, 2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane, bis(3-ethyl-5-methyl)propane, etc.), and the like. Examples of the maleimide compounds include bis(3,5-dimethyl-4-maleimidophenyl)methane, bis(3,5-diethyl-4-maleimidophenyl)methane), m-phenylene bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, maleimide compounds represented by the following formula (3), maleimide compounds represented by the following formula (3'), and prepolymers of these maleimide compounds and amine compounds.
(In formula (3), each _R5 independently represents a hydrogen atom or a methyl group, and _n1 represents an integer of 1 or more.)

_n1 is 1 or more, preferably 1 to 100, and more preferably 1 to 10.

These maleimide compounds F1 may be used alone or in combination of two or more. Among these, from the viewpoint of further improving low thermal expansion and chemical resistance, the maleimide compound F1 is preferably a compound having two or more maleimide groups in one molecule, and more preferably includes at least one selected from the group consisting of bis(4-maleimidophenyl)methane, 2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, a maleimide compound represented by formula (3), and a maleimide compound represented by the following formula (3').

(In formula (3'), each R ¹³ independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and n ⁴ represents an integer of 1 to 10.)

The maleimide compound F1 may be a commercially available product or a product produced by a known method. Commercially available maleimide compounds F1 include "BMI-70", "BMI-80", and "BMI-1000P" manufactured by K.I. Chemical Industry Co., Ltd., "BMI-3000", "BMI-4000", "BMI-5100", "BMI-7000", and "BMI-2300" manufactured by Daiwa Kasei Kogyo Co., Ltd., and "MIR-3000-MT" manufactured by Nippon Kayaku Co., Ltd. (a mixture in which all R ¹³ in formula (3') are hydrogen atoms and n ⁴ is 1 to 10).
etc.

From the viewpoint of further improving low thermal expansion and chemical resistance, the content of maleimide compound F1 is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 40 parts by mass, per 100 parts by mass of the total resin solid content.

(Cyanate ester compound F2)
From the viewpoint of further improving the heat resistance, low thermal expansion, copper foil adhesion, and chemical resistance, the thermosetting resin composition of the present embodiment preferably contains a cyanate ester compound F2. The cyanate ester compound F2 is not particularly limited as long as it is a compound having two or more aromatic moieties substituted with at least one cyanate group (cyanate ester group) in the molecule, and examples thereof include naphthol aralkyl cyanate ester compounds such as the compound represented by the following formula (4), novolac cyanate ester compounds such as the compound represented by the following formula (5) excluding the compound represented by formula (4), biphenyl aralkyl cyanate esters, diallyl bisphenyl cyanate ester compounds, bis(3,3-dimethyl-4-cyanatophenyl)methane, bis(4-cyanatophenyl) Examples of the cyanate ester compound F2 include methane, 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, 1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis(4-cyanatophenyl)ether, bis(4-cyanatophenyl)thioether, bis(4-cyanatophenyl)sulfone, and 2,2-bis(4-cyanatophenyl)propane. These cyanate ester compounds F2 may be used alone or in combination of two or more. In this embodiment, from the viewpoints of heat resistance, low thermal expansion, copper foil adhesion, and chemical resistance, it is preferable that the cyanate ester compound F2 contains a polyfunctional cyanate ester compound such as a naphthol aralkyl type cyanate ester compound and/or a novolac type cyanate ester compound.
(In formula (4), each _R6 independently represents a hydrogen atom or a methyl group, and _n2 represents an integer of 1 or more.)
(In formula (5), each Rya independently represents an alkenyl group having 2 to 8 carbon atoms or a hydrogen atom; each Ryb independently represents an alkyl group having 1 to 10 carbon atoms or a hydrogen atom; each Ryc independently represents an aromatic ring having 4 to 12 carbon atoms or a hydrogen atom; Ryc may form a condensed structure with a benzene ring; Ryc may or may not be present; each A ^1a independently represents an alkylene group having 1 to 6 carbon atoms, an aralkylene group having 7 to 16 carbon atoms, an arylene group having 6 to 10 carbon atoms, a fluorenylidene group, a sulfonyl group, an oxygen atom, a sulfur atom, or a direct bond (single bond); when Ryc is a hydrogen atom, one benzene ring may have two or more Rya and/or Ryb groups; and n represents an integer of 1 to 20.)

Among these, it is preferable that the cyanate ester compound F2 contains a compound represented by formula (4) and/or formula (5) from the viewpoint of further improving heat resistance, low thermal expansion, copper foil adhesion, and chemical resistance.

In formula (4), n ₂ represents an integer of 1 or more, preferably an integer of 1 to 20, and more preferably an integer of 1 to 10.

In formula (5), the alkenyl group having 2 to 8 carbon atoms represented by Rya is not particularly limited, but examples thereof include a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group.

In formula (5), the alkyl group having 1 to 10 carbon atoms represented by Ryb is not particularly limited, but examples thereof include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexyl groups; and branched alkyl groups such as isopropyl, isobutyl, and tert-butyl groups.

In formula (5), the alkylene group having 1 to 6 carbon atoms represented by A ^1a is not particularly limited, but examples thereof include a methylene group, an ethylene group, a trimethylene group, and a propylene group. In addition, in formula (5), the aralkylene group having 7 to 16 carbon atoms represented by A ^1a is not particularly limited, but examples thereof include a group represented by the formula: -CH ₂ -Ar-CH ₂ -, -CH ₂ -CH ₂ -Ar-CH ₂ -CH ₂ -, or the formula: -CH ₂ -Ar-CH ₂ -CH ₂ - (wherein Ar represents a phenylene group, a naphthylene group, or a biphenylene group). In addition, the arylene group having 6 to 10 carbon atoms represented by A ^1a is not particularly limited, but examples thereof include a phenylene ring.

In formula (5), n represents an integer from 1 to 20, preferably an integer from 1 to 15, and more preferably an integer from 1 to 10.

The compound represented by formula (5) is preferably a compound represented by the following formula (c1):
(In formula (c1), each Rx independently represents a hydrogen atom or a methyl group, each R independently represents an alkenyl group having 2 to 8 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or a hydrogen atom, and n represents an integer of 1 to 10.)

These cyanate ester compounds F2 may be produced according to known methods. Specific production methods include, for example, those described in JP-A-2017-195334 (particularly paragraphs 0052 to 0057).

From the viewpoint of further improving heat resistance, low thermal expansion, copper foil adhesion, and chemical resistance, the content of cyanate ester compound F2 is preferably 5 to 70 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 10 to 40 parts by mass, per 100 parts by mass of the total resin solids.

(Phenol Compound A' Other Than Alkenylphenol A)
The thermosetting resin composition of the present embodiment may contain a phenolic compound A' other than alkenylphenol A from the viewpoint of exhibiting even better chemical resistance. The phenolic compound A' is not particularly limited, but includes bisphenol-type phenolic resins (e.g., bisphenol A-type resins, bisphenol E-type resins, bisphenol F-type resins, bisphenol S-type resins, etc.), phenol novolac resins (e.g., phenol novolac resins, naphthol novolac resins, cresol novolac resins, aminotriazine novolac resins described below, etc.), glycidyl ester-type phenolic resins, naphthalene-type phenolic resins, anthracene-type phenolic resins, dicyclopentadiene-type phenolic resins, biphenyl-type phenolic resins, alicyclic phenolic resins, polyol-type phenolic resins, aralkyl-type phenolic resins (e.g., naphthol aralkyl-type phenolic resins), phenol-modified aromatic hydrocarbon formaldehyde resins, and fluorene-type phenolic resins. These phenolic compounds may be used alone or in combination of two or more.

Among these, it is preferable that the phenol compound A' contains a bifunctional phenol compound having two phenolic hydroxyl groups in one molecule or an aminotriazine novolac resin, from the viewpoint of achieving even better chemical resistance.

The bifunctional phenol compound is not particularly limited, but includes bisphenol, biscresol, bisphenols having a fluorene skeleton (e.g., bisphenols having a fluorene skeleton, biscresols having a fluorene skeleton, etc.), biphenols (e.g., p,p'-biphenol, etc.), dihydroxydiphenyl ethers (e.g., 4,4'-dihydroxydiphenyl ether, etc.), dihydroxydiphenyl ketones (e.g., 4,4'-dihydroxydiphenyl ketone, etc.), dihydroxydiphenyl sulfides (e.g., 4,4'-dihydroxydiphenyl sulfide, etc.), and dihydroxyarenes (e.g., hydroquinone, etc.). These bifunctional phenol compounds are used alone or in combination of two or more. Among these, from the viewpoint of being able to exhibit even better chemical resistance, the bifunctional phenol compound preferably contains one or more selected from the group consisting of bisphenols, biscresols, and bisphenols having a fluorene skeleton, and more preferably contains bisphenols having a fluorene skeleton. From the same viewpoint as above, biscresolfluorene is preferable as a bisphenol having a fluorene skeleton.

As described above, the thermosetting resin composition of this embodiment may contain an aminotriazine novolac resin as the phenol compound A'. When the aminotriazine novolac resin is contained, the terminal hydroxyl groups and epoxy groups generated by the reaction of the alkenylphenol A, the epoxy-modified silicone B, and the epoxy compound C other than the epoxy-modified silicone B further react with the aminotriazine novolac resin, which tends to increase the number of terminal functional groups such as hydroxyl groups and amino groups. As a result, there are many terminal functional groups that are highly reactive with the thermosetting resin, which tends to improve compatibility and crosslinking density and improve copper foil peel strength.

The aminotriazine novolac resin is not particularly limited, but from the viewpoint of improving the copper foil peel strength, it is preferable that the novolac resin has 2 to 20 phenolic hydroxyl groups per triazine skeleton in the molecule, more preferable that the novolac resin has 2 to 15 phenolic hydroxyl groups per triazine skeleton in the molecule, and even more preferable that the novolac resin has 2 to 10 phenolic hydroxyl groups per triazine skeleton in the molecule.

From the viewpoint of further improving the balance between heat resistance and low thermal expansion, the content of alkenylphenol A in the thermosetting resin composition of this embodiment is preferably 1 to 50 parts by mass, more preferably 3 to 30 parts by mass, and even more preferably 5 to 20 parts by mass, relative to 100 parts by mass of the total amount of alkenylphenol A, epoxy-modified silicone B, epoxy compound C, and phenol compound A'.

From the viewpoint of achieving a good balance between low thermal expansion and chemical resistance, the content of the epoxy-modified silicone B in the thermosetting resin composition of this embodiment is preferably 5 to 70 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 20 to 55 parts by mass, relative to 100 parts by mass of the total amount of the alkenylphenol A, the epoxy-modified silicone B, the epoxy compound C, and the phenol compound A'.

The content of the epoxy compound C in the thermosetting resin composition of this embodiment is preferably 5 to 50 parts by mass, more preferably 10 to 30 parts by mass, and even more preferably 15 to 25 parts by mass, per 100 parts by mass of the total amount of the alkenylphenol A, the epoxy-modified silicone B, the epoxy compound C, and the phenol compound A', from the viewpoint of achieving even better chemical resistance, copper foil adhesion, and insulation reliability.

From the viewpoint of achieving even better chemical resistance, the content of the phenol compound A' in the thermosetting resin composition of this embodiment is preferably 5 to 30 parts by mass, more preferably 10 to 25 parts by mass, and even more preferably 15 to 20 parts by mass, per 100 parts by mass of the total amount of the alkenylphenol A, the epoxy-modified silicone B, the epoxy compound C, and the phenol compound A'.

When the thermosetting resin composition does not contain the phenol compound A', the contents of the alkenylphenol A, the epoxy-modified silicone B, and the epoxy compound C described above represent the contents per 100 parts by mass of the total amount of the alkenylphenol A, the epoxy-modified silicone B, and the epoxy compound C.

(Alkenyl-substituted nadiimide compounds)
The thermosetting resin composition of the present embodiment may contain an alkenyl-substituted nadiimide compound from the viewpoint of further improving heat resistance. The alkenyl-substituted nadiimide compound is not particularly limited as long as it is a compound having one or more alkenyl-substituted nadiimide groups in one molecule, and examples thereof include compounds represented by the following formula (2d).
(In formula (2d), each R ₁ independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (e.g., a methyl group or an ethyl group), and R ₂ represents an alkylene group having 1 to 6 carbon atoms, a phenylene group, a biphenylene group, a naphthylene group, or a group represented by the following formula (6) or (7).)
(In formula (6), _R3 represents a methylene group, an isopropylidene group, CO, O, S, or _SO2 .)
(In formula (7), each R ₄ independently represents an alkylene group having 1 to 4 carbon atoms or a cycloalkylene group having 5 to 8 carbon atoms.)

The alkenyl-substituted nadiimide compound represented by formula (2d) may be a commercially available product, or a product produced according to a known method. Commercially available products include "BANI-M" and "BANI-X" manufactured by Maruzen Petrochemical Co., Ltd.

From the viewpoint of further improving heat resistance, the content of the alkenyl-substituted nadimide compound is preferably 1 to 40 parts by mass, more preferably 5 to 35 parts by mass, and even more preferably 10 to 30 parts by mass, per 100 parts by mass of the total resin solids.

[Other resins]
The thermosetting resin composition of the present embodiment may further contain other resins as further optional components not corresponding to the above-mentioned components. Examples of the other resins include oxetane resins, benzoxazine compounds, and compounds having a polymerizable unsaturated group. These resins may be used alone or in combination of two or more.

Examples of oxetane resins include, but are not limited to, alkyl oxetanes such as oxetane, 2-methyloxetane, 2,2-dimethyloxetane, 3-methyloxetane, and 3,3-dimethyloxetane, 3-methyl-3-methoxymethyloxetane, 3,3'-di(trifluoromethyl)perfluorooxetane, 2-chloromethyloxetane, 3,3-bis(chloromethyl)oxetane, biphenyl-type oxetane, and products of Toagosei Co., Ltd. such as "OXT-101" and "OXT-121".

As used herein, "benzoxazine compound" refers to a compound having two or more dihydrobenzoxazine rings in one molecule. Examples of benzoxazine compounds include, but are not limited to, "bisphenol F benzoxazine BF-BXZ" and "bisphenol S benzoxazine BS-BXZ" manufactured by Konishi Chemical Co., Ltd.

Examples of compounds having a polymerizable unsaturated group include, but are not limited to, vinyl compounds such as ethylene, propylene, styrene, divinylbenzene, and divinylbiphenyl; (meth)acrylates of monohydric or polyhydric alcohols such as methyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; epoxy (meth)acrylates such as bisphenol A type epoxy (meth)acrylate and bisphenol F type epoxy (meth)acrylate; and benzocyclobutene resins.

[Aromatic phosphorus compound P]
From the viewpoint of further improving low thermal expansion, the thermosetting resin composition of the present embodiment preferably further contains, as an optional component other than the above-mentioned components, an aromatic phosphorus compound P. The aromatic phosphorus compound P is not particularly limited as long as it contains a phosphorus atom in its molecule and exhibits aromaticity.

In this embodiment, from the viewpoint of flame retardancy and chemical resistance, it is preferable that the aromatic phosphorus compound P contains at least one selected from the group consisting of cyclic phosphazene compounds, phosphate ester compounds, phosphite ester compounds, and phosphaphenanthrene compounds. Among the above, from the viewpoint of further improving copper foil adhesion, it is more preferable that the aromatic phosphorus compound P contains at least one selected from the group consisting of cyclic phosphazene compounds, phosphate ester compounds, and phosphite ester compounds, more preferably contains at least one selected from the group consisting of cyclic phosphazene compounds and phosphate ester compounds, and even more preferably contains a cyclic phosphazene compound. The cyclic phosphazene compound is not particularly limited, and commercially available products can be used, such as "FP-110" manufactured by Fushimi Pharmaceutical Co., Ltd.

In this embodiment, from the viewpoint of non-volatility and chemical stability (thermal stability) during thermal curing of the thermosetting resin composition, the aromatic phosphorus compound P may also include an aromatic phosphorus compound P' represented by the following formula (P1), (P2), (P3) or (P4).
In the above formula (P1), Ph1, Ph2, and Ph3 represent a substituted or unsubstituted aryl group, and Ph1, Ph2, and Ph3 may be the same or different.
In the above formula (P2), Ph1 and Ph2 represent a substituted or unsubstituted aryl group, and Ph1 and Ph2 may be the same or different, and R represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms.
(In the above formula (P3), each A independently represents a hydrogen atom, a methyl group, a hydroxyl group, a cyano group, an amino group, a carboxyl group, a glycidyloxy group, a para-hydroxyphenyldimethyl group, a para-glycidyloxyphenyldimethyl group, a para-hydroxyphenylsulfone group, a para-glycidyloxyphenylsulfone group, an alkyl group having 2 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms; each R independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 30 carbon atoms; and n represents an integer of 3 to 15.
In the above formula (P4), R represents a hydrogen atom, an alkyl group having 2 to 30 carbon atoms, or a substituted or unsubstituted aryl group.

In this embodiment, from the viewpoint of non-volatility and chemical stability during thermal curing of the thermosetting resin composition, the aromatic phosphorus compound P may also include an aromatic phosphorus compound P″ represented by the following formula (P5).

From the viewpoint of achieving both low thermal expansion and copper foil adhesion, the content of the aromatic phosphorus compound P in the thermosetting resin composition of this embodiment is preferably 3 to 15 parts by mass, more preferably 3 to 12 parts by mass, and even more preferably 4 to 10 parts by mass, per 100 parts by mass of the total resin solids.

[Inorganic filler]
The thermosetting resin composition of the present embodiment preferably further contains an inorganic filler from the viewpoint of further improving the low thermal expansion. The inorganic filler is not particularly limited, and examples thereof include silicas, silicon compounds (e.g., white carbon, etc.), metal oxides (e.g., alumina, titanium white, zinc oxide, magnesium oxide, zirconium oxide, etc.), metal nitrides (e.g., boron nitride, aggregated boron nitride, silicon nitride, aluminum nitride, etc.), metal sulfates (e.g., barium sulfate, etc.), metal hydroxides (e.g., aluminum hydroxide, aluminum hydroxide heat-treated product (e.g., aluminum hydroxide heat-treated to remove some of the water of crystallization). , boehmite, magnesium hydroxide, etc.), molybdenum compounds (e.g., molybdenum oxide, zinc molybdate, etc.), zinc compounds (e.g., zinc borate, zinc stannate, etc.), clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, E-glass, A-glass, NE-glass, C-glass, L-glass, D-glass, S-glass, M-glass G20, glass short fibers (including glass fine powders such as E-glass, T-glass, D-glass, S-glass, and Q-glass), hollow glass, spherical glass, etc. These inorganic fillers are used alone or in combination of two or more. Among these, from the viewpoint of further improving low thermal expansion, the inorganic filler is preferably at least one selected from the group consisting of silicas, metal hydroxides, and metal oxides, more preferably at least one selected from the group consisting of silicas, boehmite, and alumina, and even more preferably silicas.

Examples of silicas include natural silica, fused silica, synthetic silica, aerosil, hollow silica, etc. These silicas may be used alone or in combination of two or more. Among these, fused silica is preferred from the viewpoint of dispersibility, and two or more types of fused silica having different particle sizes are more preferred from the viewpoint of packing ability and flowability.

From the viewpoint of further improving low thermal expansion, the content of the inorganic filler is preferably 50 to 1,000 parts by mass, more preferably 70 to 500 parts by mass, and even more preferably 100 to 300 parts by mass, per 100 parts by mass of the total resin solids.

[Silane coupling agent]
The thermosetting resin composition of the present embodiment may further contain a silane coupling agent. By containing a silane coupling agent, the thermosetting resin composition of the present embodiment tends to further improve the dispersibility of the filler and further improve the adhesive strength between the components of the thermosetting resin composition of the present embodiment and the substrate described below.

The silane coupling agent is not particularly limited, and examples thereof include silane coupling agents generally used for surface treatment of inorganic substances, such as aminosilane compounds (e.g., γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, etc.), epoxysilane compounds (e.g., γ-glycidoxypropyltrimethoxysilane, etc.), acrylsilane compounds (e.g., γ-acryloxypropyltrimethoxysilane, etc.), cationic silane compounds (e.g., N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, etc.), vinylsilane compounds (e.g., vinyltrimethoxysilane, etc.), styrylsilane compounds (e.g., styryltrimethoxysilane, etc.), phenylsilane compounds (e.g., phenyltrimethoxysilane, etc.), etc. The silane coupling agents are used alone or in combination of two or more. Among these, it is preferable that the silane coupling agent is an epoxysilane compound. Examples of epoxysilane compounds include Shin-Etsu Chemical Co., Ltd. products "KBM-403," "KBM-303," "KBM-402," and "KBE-403."

The amount of silane coupling agent is not particularly limited, but may be 0.1 to 10 parts by mass per 100 parts by mass of the total resin solids.

[Wetting and dispersing agent]
The thermosetting resin composition of the present embodiment may further contain a wetting dispersant. By containing the wetting dispersant, the thermosetting resin composition of the present embodiment tends to further improve the dispersibility of the filler.

The wetting dispersant may be any known dispersant (dispersion stabilizer) used to disperse fillers, such as DISPER BYK-110, 111, 118, 180, 161, BYK-W996, W9010, and W903 manufactured by BYK Japan Co., Ltd.

The amount of the wetting and dispersing agent is not particularly limited, but is preferably 0.5 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the total resin solids.

[Curing accelerator]
The thermosetting resin composition of the present embodiment may further contain a curing accelerator as an optional component other than the above-mentioned components. The curing accelerator may be used alone or in combination of two or more kinds.

Examples of hardening accelerators include imidazoles such as triphenylimidazole (e.g., 2,4,5-triphenylimidazole); organic peroxides such as benzoyl peroxide, lauroyl peroxide, acetyl peroxide, parachlorobenzoyl peroxide, and di-tert-butyl-di-perphthalate; azo compounds such as azobisisobutyronitrile; N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2-N-ethylanilinoethanol, tri-n-butylamine, pyridine, quinoline, N-methylmorpholine, triethanolamine, triethylenediamine, tetramethylphenyl ... Examples of suitable organic compounds include tertiary amines such as methylbutanediamine and N-methylpiperidine; phenols such as phenol, xylenol, cresol, resorcin, and catechol; organic metal salts such as lead naphthenate, lead stearate, zinc naphthenate, zinc octylate, manganese octylate, tin oleate, dibutyltin maleate, manganese naphthenate, cobalt naphthenate, and iron acetylacetonate; organic metal salts obtained by dissolving these organic metal salts in hydroxyl-containing compounds such as phenol and bisphenol; inorganic metal salts such as tin chloride, zinc chloride, and aluminum chloride; and organic tin compounds such as dioctyltin oxide, other alkyl tins, and alkyl tin oxides. Among these, manganese octylate is preferred because it promotes the curing reaction and tends to further improve the glass transition temperature.

The amount of the curing accelerator is not particularly limited, but is preferably 0.1 to 5.0 parts by mass per 100 parts by mass of the total resin solids.

[solvent]
The thermosetting resin composition of the present embodiment may further contain a solvent. By including a solvent in the thermosetting resin composition of the present embodiment, the viscosity of the thermosetting resin composition during preparation tends to be lowered, and the handleability (handling ability) and the impregnation ability into a substrate tend to be further improved.

The solvent is not particularly limited as long as it can dissolve a part or all of the components in the thermosetting resin composition, but examples include ketones (acetone, methyl ethyl ketone, etc.), aromatic hydrocarbons (for example, toluene, xylene, etc.), amides (for example, dimethylformaldehyde, etc.), propylene glycol monomethyl ether and its acetate, etc. These solvents may be used alone or in combination of two or more.

The method for producing the thermosetting resin composition of this embodiment is not particularly limited, and examples include a method in which each component is mixed in a solvent all at once or sequentially and stirred. At this time, known processes such as stirring, mixing, and kneading are used to uniformly dissolve or disperse each component.

[Other Components H]
The thermosetting resin composition of the present embodiment may contain other components H as further optional components not corresponding to the above-mentioned components. The other components H may contain, for example, flame retardant compounds, and examples of the flame retardant compounds include bromine compounds such as 4,4'-dibromobiphenyl, nitrogen-containing compounds such as melamine and benzoguanamine, and silicon-based compounds. In addition to the above-mentioned components, the other components H may include various known components such as ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, lubricants, defoamers, leveling agents (surface conditioners), gloss agents, and polymerization inhibitors.

[Application]
As described above, the thermosetting resin composition of this embodiment can exhibit excellent heat resistance, low thermal expansion, and interlayer adhesion. Therefore, the thermosetting resin composition of this embodiment is preferably used for metal foil-clad laminates and printed wiring boards. The thermosetting resin composition of this embodiment can be applied to the above-mentioned applications by curing. That is, the cured product of this embodiment is obtained by curing the thermosetting resin composition of this embodiment. The first composition can also be used as a raw material composition for obtaining the second composition in that the polymer E can be produced by placing it under conditions in which the alkenylphenol A, the epoxy-modified silicone B, and the epoxy compound C contained therein react with each other.

In particular, in the above-mentioned applications, the second composition preferably contains, in addition to the polymer E and the aluminum chelate complex D, at least an epoxy compound C (epoxy compound C present separately from the structural unit C in the polymer E).
In this case, the polymer E preferably has, as the unit derived from the epoxy compound C, a unit derived from the bifunctional epoxy compound described above, more preferably a unit derived from the biphenyl type epoxy resin described above, still more preferably a unit derived from the compound represented by the above formula (b2) (compound b2), and still more preferably a unit derived from a compound b2 in which the number of R ^a is 0 and a compound b2 in which the number of R ^a, which is an alkyl group, is 4 (for example, a commercially available product such as the product name "YL-6121H" manufactured by Mitsubishi Chemical Corporation).
In addition, the epoxy compound C present in addition to the structural unit C in the polymer E preferably contains the above-mentioned naphthylene ether type epoxy resin (a commercially available product is, for example, "HP-6000" manufactured by DIC Corporation) and/or a naphthalene cresol novolac type epoxy resin (a commercially available product is, for example, "HP-9540" manufactured by DIC Corporation), and more preferably contains a naphthylene ether type epoxy resin.

[Prepreg]
The thermosetting resin composition of the present embodiment is preferably used for a prepreg. The prepreg of the present embodiment includes a substrate and the thermosetting resin composition of the present embodiment impregnated or applied to the substrate. Since the prepreg of the present embodiment is configured as described above, when applied to a metal foil-clad laminate and a printed wiring board, it has excellent heat resistance, low thermal expansion, and interlayer adhesion.

The prepreg of this embodiment includes a substrate and a thermosetting resin composition impregnated or applied to the substrate. The prepreg may be a prepreg obtained by a known method, and a specific example of the prepreg is obtained by impregnating or applying the thermosetting resin composition of this embodiment to a substrate, and then semi-curing (B-stage) by heating and drying at 100 to 200°C.

The prepreg of this embodiment also includes the form of a cured product obtained by thermally curing a semi-cured prepreg at a heating temperature of 180 to 230°C for a heating time of 60 to 180 minutes.

The content of the thermosetting resin composition in the prepreg is preferably 30 to 90% by volume, more preferably 35 to 85% by volume, and even more preferably 40 to 80% by volume, calculated as the solid content of the prepreg relative to the total amount of the prepreg. When the content of the thermosetting resin composition is within the above range, moldability tends to be further improved. Note that the calculation of the content of the thermosetting resin composition here includes the cured product of the thermosetting resin composition of this embodiment. Also, the solid content of the prepreg here refers to the components remaining after removing the solvent from the prepreg. For example, the filler is included in the solid content of the prepreg.

The substrate is not particularly limited, and examples thereof include known substrates used as materials for various printed wiring boards. Specific examples of substrates include glass substrates, inorganic substrates other than glass (e.g., inorganic substrates composed of inorganic fibers other than glass, such as quartz), and organic substrates (e.g., organic substrates composed of organic fibers, such as wholly aromatic polyamide, polyester, polyparaphenylenebenzoxazole, and polyimide). These substrates may be used alone or in combination of two or more. Among these, glass substrates are preferred from the viewpoint of being more excellent in dimensional stability under heating.

Examples of fibers constituting the glass substrate include fibers such as E glass, D glass, S glass, T glass, Q glass, L glass, NE glass, and HME glass. Among these, from the viewpoint of even greater strength and low water absorption, it is preferable that the fibers constituting the glass substrate are one or more types of fibers selected from the group consisting of E glass, D glass, S glass, T glass, Q glass, L glass, NE glass, and HME glass.

The form of the substrate is not particularly limited, but examples include woven fabric, nonwoven fabric, roving, chopped strand mat, surfacing mat, etc. The weaving method of the woven fabric is not particularly limited, but examples of known weaving methods include plain weave, sash weave, twill weave, etc., and these known weaves can be appropriately selected and used depending on the intended use and performance. In addition, glass woven fabrics that have been subjected to fiber opening treatment or surface treatment with a silane coupling agent or the like are preferably used. The thickness and mass of the substrate are not particularly limited, but typically those of about 0.01 to 0.1 mm are preferably used.

[Resin sheet]
The resin sheet of this embodiment includes the thermosetting resin composition of this embodiment. The resin sheet may be a resin sheet with a support, which includes a support and a layer formed from the thermosetting resin composition of this embodiment arranged on the surface of the support. The resin sheet can be used as a build-up film or a dry film solder resist. The method for producing the resin sheet is not particularly limited, but for example, a method of obtaining a resin sheet by applying (coating) a solution in which the thermosetting resin composition of this embodiment is dissolved in a solvent to a support and drying the solution can be mentioned.

Examples of the support include, but are not limited to, polyethylene film, polypropylene film, polycarbonate film, polyethylene terephthalate film, ethylene tetrafluoroethylene copolymer film, and release films obtained by applying a release agent to the surface of these films, organic film substrates such as polyimide film, conductive foils such as copper foil and aluminum foil, glass plates, SUS plates, FRP, and other plate-shaped substrates.

Examples of the application method (coating method) include a method in which a solution in which the thermosetting resin composition of this embodiment is dissolved in a solvent is applied onto a support using a bar coater, a die coater, a doctor blade, a baker applicator, or the like. In addition, after drying, a single-layer sheet (resin sheet) can be obtained by peeling or etching the support from a resin sheet with a support in which the support and the thermosetting resin composition are laminated. Note that a single-layer sheet (resin sheet) can also be obtained without using a support by supplying a solution in which the thermosetting resin composition of this embodiment is dissolved in a solvent into a mold having a sheet-shaped cavity and drying it to form it into a sheet.

In the preparation of the monolayer sheet or the resin sheet with a support according to the present embodiment, the drying conditions for removing the solvent are not particularly limited, but from the viewpoint of making it easier to remove the solvent in the thermosetting resin composition and suppressing the progress of curing during drying, a temperature of 20 to 200°C for 1 to 90 minutes is preferred. In addition, in the monolayer sheet or the resin sheet with a support, the thermosetting resin composition can be used in an uncured state in which the solvent has simply been dried, or can be used in a semi-cured (B-stage) state as necessary. Furthermore, the thickness of the resin layer of the monolayer sheet or the resin sheet with a support according to the present embodiment can be adjusted by the concentration of the solution of the thermosetting resin composition of the present embodiment and the coating thickness, and is not particularly limited, but from the viewpoint of making it easier to remove the solvent during drying, 0.1 to 500 μm is preferred.

[Metal foil laminate]
The metal foil-clad laminate of the present embodiment includes a laminate containing the prepreg of the present embodiment and/or a cured product obtained by curing the prepreg, and a metal foil arranged on one or both sides of the laminate. The laminate may include one prepreg and/or cured product, or may include multiple prepregs and/or cured products.

The metal foil (conductor layer) may be any metal foil used in various printed wiring board materials, such as copper or aluminum foil, and examples of copper foil include rolled copper foil and electrolytic copper foil. The thickness of the conductor layer is, for example, 1 to 70 μm, and preferably 1.5 to 35 μm.

The molding method and molding conditions of the metal foil-clad laminate are not particularly limited, and general methods and conditions for laminates and multilayer boards for printed wiring boards can be applied. For example, a multi-stage press machine, a multi-stage vacuum press machine, a continuous molding machine, an autoclave molding machine, etc. can be used when molding a laminate or a metal foil-clad laminate. In addition, in molding (lamination molding) a laminate or a metal foil-clad laminate, the temperature is generally 100 to 300°C, the pressure is 2 to 100 kgf/cm ² , and the heating time is generally in the range of 0.05 to 5 hours. Furthermore, if necessary, post-curing can be performed at a temperature of 150 to 300°C. In particular, when a multi-stage press is used, from the viewpoint of sufficiently promoting the curing of the prepreg, a temperature of 200° C. to 250° C., a pressure of 10 to 40 kgf/cm ² and a heating time of 80 to 130 minutes are preferred, and a temperature of 215° C. to 235° C., a pressure of 25 to 35 kgf/cm ² and a heating time of 90 to 120 minutes are more preferred. It is also possible to form a multilayer board by combining the above-mentioned prepreg with a separately prepared wiring board for an inner layer and laminating and molding it.

[Printed wiring board]
The printed wiring board of the present embodiment has an insulating layer containing a cured product obtained by curing the prepreg of the present embodiment, and a conductor layer formed on the surface of the insulating layer. The printed wiring board of the present embodiment can be formed, for example, by etching the metal foil of the metal foil-clad laminate of the present embodiment into a predetermined wiring pattern to form the conductor layer.

Specifically, the printed wiring board of this embodiment can be manufactured, for example, by the following method. First, the metal foil-clad laminate of this embodiment is prepared. The metal foil of the metal foil-clad laminate is etched into a predetermined wiring pattern to create an inner layer substrate having a conductor layer (inner layer circuit). Next, a predetermined number of insulating layers and metal foil for the outer layer circuit are laminated in this order on the surface of the conductor layer (interior circuit) of the inner layer substrate, and the laminate is integrally molded (lamination molding) by heating and pressing to obtain a laminate. The method and molding conditions for the laminate molding are the same as those for the laminate and metal foil-clad laminate described above. Next, the laminate is subjected to a hole punching process for through holes and via holes, and a plated metal film is formed on the wall surface of the hole to conduct the conductor layer (interior circuit) and the metal foil for the outer layer circuit. Next, the metal foil for the outer layer circuit is etched into a predetermined wiring pattern to create an outer layer substrate having a conductor layer (outer layer circuit). In this manner, a printed wiring board is manufactured.

In addition, when a metal foil-clad laminate is not used, a conductor layer that serves as a circuit may be formed on the insulating layer to produce a printed wiring board. In this case, electroless plating may be used to form the conductor layer.

The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to these examples.

Synthesis Example 1 Synthesis of 1-naphthol aralkyl cyanate ester compound (SN495V-CN) 300 ^{g (1.28 mol in terms of hydroxyl groups) of an α-naphthol aralkyl phenolic resin (SN495V, hydroxyl group equivalent: 236 g/eq., manufactured by Nippon Steel Chemical Co., Ltd.) in which all of R 2a} in the following formula (2b) are hydrogen atoms, and 194.6 g (1.92 mol) of triethylamine (1.5 mol per mol of hydroxyl groups) were dissolved in 1800 g of dichloromethane, and the resulting solution was designated as solution 1. 125.9g (2.05mol) of cyanogen chloride (1.6mol per 1mol of hydroxyl group), 293.8g of dichloromethane, 194.5g (1.92mol) of 36% hydrochloric acid (1.5mol per 1mol of hydroxyl group), and 1205.9g of water were poured over 30 minutes while stirring and maintaining the liquid temperature at -2 to -0.5°C. After the end of pouring of solution 1, the mixture was stirred at the same temperature for 30 minutes, and then a solution (solution 2) in which 65g (0.64mol) of triethylamine (0.5mol per 1mol of hydroxyl group) was dissolved in 65g of dichloromethane was poured over 10 minutes. After the end of pouring of solution 2, the mixture was stirred at the same temperature for 30 minutes to complete the reaction. Thereafter, the reaction liquid was left to stand to separate the organic phase and the aqueous phase. The obtained organic phase was washed five times with 1300g of water. The electrical conductivity of the wastewater from the fifth water wash was 5 μS/cm, confirming that ionic compounds that can be removed by washing with water were sufficiently removed. The organic phase after water washing was concentrated under reduced pressure and finally concentrated to dryness at 90° C. for 1 hour to obtain 331 g of the target 1-naphthol aralkyl cyanate ester compound (SN495V-CN, cyanate group equivalent: 261 g/eq.) (orange viscous material). The infrared absorption spectrum of the obtained SN495V-CN showed an absorption at 2250 cm ^-1 (cyanate group) and no absorption of hydroxyl groups.
(In the formula, R ^2a represents a hydrogen atom, and m represents an integer of 1 to 10.)

Example 1
(Polymer production process)
A three-neck flask equipped with a thermometer and Dimroth
Diallyl bisphenol A (DABPA, Daiwa Chemical Industry Co., Ltd.) 5 parts by mass,
Biscresolfluorene (BCF, Osaka Gas Chemical Co., Ltd.) 5 parts by mass,
Epoxy-modified silicone b1 (X-22-163, Shin-Etsu Chemical Co., Ltd., functional group equivalent: 200 g/mol) 4 parts by mass,
Epoxy-modified silicone b2 (KF-105, Shin-Etsu Chemical Co., Ltd., functional group equivalent: 490 g/mol) 11 parts by mass,
Biphenyl-type epoxy resin c1 (YL-6121H, Mitsubishi Chemical Corporation) 5 parts by mass,
As a solvent, 30 parts by mass of propylene glycol monomethyl ether acetate (DOWANOL PMA, Dow Chemical Japan Co., Ltd.) was added, and the mixture was heated and stirred in an oil bath to 120° C. After confirming that the raw materials had dissolved in the solvent, 0.3 parts by mass of an imidazole catalyst (TBZ, Shikoku Chemical Industry Co., Ltd.) was added, and the mixture was heated to 140° C. and stirred for 5 hours. After cooling, a phenoxy polymer solution (solid content 50% by mass) was obtained.

The above-mentioned diallyl bisphenol A corresponds to "alkenylphenol A", biscresol fluorene corresponds to "phenolic compound A'", epoxy-modified silicone b1 and epoxy-modified silicone b2 correspond to "epoxy-modified silicone B", and biphenyl-type epoxy resin c1 corresponds to "epoxy compound C". The above-mentioned phenoxy polymer solution contained a polymer corresponding to "polymer E containing a structural unit derived from alkenylphenol A, a structural unit derived from phenolic compound A', a structural unit derived from epoxy-modified silicone B, and a structural unit derived from epoxy compound C". Hereinafter, this polymer is also referred to as a phenoxy polymer. In this phenoxy polymer, the content of structural unit B relative to polymer E was 50% by mass, and the content of structural unit C relative to the total amount of structural units B and C was 25% by mass.

(Method of measuring weight average molecular weight Mw)
The weight average molecular weight Mw of the phenoxy polymer obtained as described above was measured as follows. 20 μL of a solution obtained by dissolving 0.5 g of the phenoxy polymer solution in 2 g of THF was injected into a high performance liquid chromatography (manufactured by Shimadzu Corporation, pump: LC-20AD) and analyzed. A total of four columns were used, including Showa Denko Shodex GPC KF-804 (length 30 cm x inner diameter 8 mm), Shodex GPC KF-803 (length 30 cm x inner diameter 8 mm), Shodex GPC KF-802 (length 30 cm x inner diameter 8 mm), and Shodex GPC KF-801 (length 30 cm x inner diameter 8 mm), with THF (solvent) as the mobile phase, a flow rate of 1 mL/min, and a detector RID-10A. The weight average molecular weight Mw was determined by GPC using standard polystyrene as the standard substance. The weight average molecular weight Mw of the phenoxy polymer measured as above was 12,000.

(Varnish production process)
To the above phenoxy polymer solution (30.3 parts by mass in terms of solid content; 30 parts by mass as resin solid content),
16 parts by mass of the 1-naphthol aralkyl cyanate ester compound (SN495V-CN, cyanate group equivalent: 261 g/eq.) obtained in Synthesis Example 1,
Novolac-type maleimide compound (BMI-2300, Daiwa Chemical Industry Co., Ltd.) 16 parts by mass,
Bismaleimide compound (BMI-70, K.I. Chemical Co., Ltd.) 7 parts by mass,
31 parts by mass of naphthylene ether type epoxy resin (HP-6000, DIC Corporation, functional group equivalent: 250 g/mol),
5 parts by mass of a phosphazene derivative (FP-110, Fushimi Pharmaceutical Co., Ltd.) as a phosphorus-based flame retardant,
150 parts by mass of slurry silica (SC-2050MB, Admatechs Co., Ltd.) as a filler,
Wetting and dispersing agent (DISPERBYK-161, BYK Japan Co., Ltd.) 1 part by mass,
Silane coupling agent (KBM-403, Shin-Etsu Chemical Co., Ltd.) 5 parts by mass,
Tris(ethylacetoacetate)aluminum(III)
were mixed to obtain a varnish.
Here, the above-mentioned mass parts are values based on 100 mass parts of the total resin solid content (the same applies in each of the following examples), and tris(ethylacetoacetate)aluminum (III) was added in an amount of 0.15 mass parts per 100 mass parts of the total resin solid content.

(Prepreg manufacturing process)
This varnish was applied to an S-glass woven fabric (thickness 100 μm) by impregnation and then dried by heating at 165° C. for 5 minutes to obtain a prepreg having a thermosetting resin composition solids content (including filler) of 58.2 vol. %.

Example 2
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 1, except for the following: In the varnish production step, the content of tris(ethylacetoacetate)aluminum (III) was changed to 0.3 parts by mass.

Example 3
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 1, except for the following: In the varnish production step, the content of tris(ethylacetoacetate)aluminum (III) was changed to 0.6 parts by mass.

Example 4
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 1, except for the following: In the varnish production step, the content of tris(ethylacetoacetate)aluminum (III) was changed to 1 part by mass.

Example 5
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 2, except for the following: 0.05 part by mass of manganese octylate was further mixed in the varnish production step.

Example 6
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 3, except for the following: 0.05 parts by mass of manganese octylate was further mixed in the varnish production step.

(Example 7)
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 1, except for the following: In the varnish production step, tris(2,4-pentanedionato)aluminum(III) was mixed in place of 0.15 part by mass of tris(ethylacetoacetate)aluminum(III) so that the content was 0.1 part by mass.

(Example 8)
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 7, except for the following: In the varnish production step, the content of tris(2,4-pentanedionato)aluminum(III) was changed to 0.3 parts by mass.

(Comparative Example 1)
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2 volume % was obtained in the same manner as in Example 1, except for the following: In the varnish production step, a varnish was obtained without mixing tris(ethylacetoacetate)aluminum(III).

(Comparative Example 2)
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 1, except for the following: In the varnish production step, triphenylimidazole was mixed in place of 0.15 part by mass of tris(ethylacetoacetate)aluminum(III) so that the content was 0.2 part by mass.

(Comparative Example 3)
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 1, except for the following: In the varnish production step, manganese octylate was mixed in place of 0.15 part by mass of tris(ethylacetoacetate)aluminum(III) so that the content was 0.1 part by mass.

(Comparative Example 4)
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Example 1, except for the following: In the varnish production step, 2-ethyl-4-methylimidazole was mixed in place of 0.15 part by mass of tris(ethylacetoacetate)aluminum (III) so that the content was 0.3 part by mass.

(Comparative Example 5)
A prepreg with a thermosetting resin composition solids content (including filler) of 58.2% by volume was obtained in the same manner as in Example 1, except for the following: in the varnish production step, the phenoxy polymer solution and tris(ethylacetoacetate)aluminum (III) were not mixed, the amount of SN495V-CN used was changed to 23 parts by mass, the amount of BMI-2300 used was changed to 23 parts by mass, the amount of BMI-70 used was changed to 10 parts by mass, and the amount of HP-6000 used was changed to 44 parts by mass.

(Comparative Example 6)
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Comparative Example 5, except for the following: In the varnish production step, tris(ethylacetoacetate)aluminum (III) was further mixed in such that the content was 0.6 parts by mass.

(Comparative Example 7)
A prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume was obtained in the same manner as in Comparative Example 5, except for the following: In the varnish production step, the amount of SN495V-CN used was changed to 13 parts by mass, the amount of BMI-2300 used was changed to 13 parts by mass, the amount of BMI-70 used was changed to 5 parts by mass, and the amount of HP-6000 used was changed to 69 parts by mass.

(Manufacturing of metal foil-clad laminates)
The prepregs obtained in Examples 1 to 8 and Comparative Examples 1 to 7 (hereinafter also referred to as "each example") were stacked to form a laminate, and 12 μm thick electrolytic copper foil (3EC-VLP (product name), manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on both sides of this laminate, and laminate molding was performed by vacuum pressing at a pressure of 30 kgf/cm ² , 230° C., and 100 minutes to produce a metal foil-clad laminate (double-sided copper-clad laminate). Two sheets of prepreg (laminated insulating layer thickness 0.22 mm) or ten sheets (laminated insulating layer thickness 1.02 mm) were used to produce the laminate. The properties of the obtained metal foil-clad laminate were evaluated by the method shown below. The evaluation results are shown in Table 1.

(Glass Transition Temperature (Tg))
The metal foil-clad laminate obtained in each example was cut into a size of 5 mm x 10 mm x 0.22 mm with a dicing saw, and the copper foil on the surface was removed by etching to obtain a measurement sample. Using this measurement sample, the loss modulus E'' was measured by the DMA method using a dynamic viscoelasticity analyzer (manufactured by TA Instruments) in accordance with JIS C6481, and the peak (maximum point) value of E'' was taken as Tg (unit: ° C.). The obtained Tg value was evaluated according to the following criteria.
A: Over 280°C B: Over 265°C and below 280°C C: Over 250°C and below 265°C D: Below 250°C

(Coefficient of Linear Thermal Expansion (CTE))
The linear thermal expansion coefficient in the longitudinal direction of the glass cloth was measured for the insulating layer of the metal foil-clad laminate obtained in each example. Specifically, the copper foil on both sides of the copper foil-clad laminate (10 mm x 6 mm x 0.22 mm) obtained above was removed by etching, and then heated in a thermostatic chamber at 220 ° C for 2 hours to remove stress due to molding. Thereafter, using a thermal expansion measuring device (horizontal dilatometer DIL L75 PT manufactured by Linseis), the temperature was raised from 30 ° C to 260 ° C at 10 ° C per minute, then cooled to 30 ° C, and reheated again from 30 ° C to 260 ° C at 10 ° C per minute. The linear thermal expansion coefficient (CTE) (unit: ppm / ° C) from 30 ° C to 260 ° C during the reheating was measured, and the average value of the linear thermal expansion coefficient from 30 ° C to 260 ° C was taken as the linear thermal expansion coefficient of each example. The obtained linear thermal expansion coefficient value was evaluated according to the following criteria.
○: 7ppm/℃ or less ×: More than 7ppm/℃

(Interlayer adhesion strength)
The copper foil-clad laminate (10 mm x 130 mm x 1.02 mm) obtained by the above method was used, and both ends were fixed, and the glass cloth of the first outer layer was pulled together with the copper foil in a direction perpendicular to the test surface (pulling speed 50 mm/min) to measure the peel strength. A precision universal testing machine (Shimadzu Corporation, Autograph AG-X plus) was used for the measurement. Measurements were performed on four samples, and the average value of the peel strength was taken as the interlayer adhesion strength for each example.

Claims (18)

a polymer E containing a structural unit derived from an alkenylphenol A, a structural unit derived from an epoxy-modified silicone B, and a structural unit derived from an epoxy compound C different from the epoxy-modified silicone B;
Aluminum chelate complex D;
A thermosetting resin composition comprising: The thermosetting resin composition according to claim 1, wherein the ligand of the aluminum chelate complex D is a bidentate ligand. The thermosetting resin composition according to claim 1, wherein the ligand of the aluminum chelate complex D includes acetylacetone, an acetylacetone derivative, and/or an alkyl acetoacetate ester. The thermosetting resin composition according to claim 1, wherein the alkenylphenol A contains diallyl bisphenol and/or dipropenyl bisphenol. The thermosetting resin composition according to claim 1, wherein the epoxy-modified silicone B contains epoxy-modified silicone B1 having an epoxy equivalent of 140 to 250 g/mol. The thermosetting resin composition according to claim 1, wherein the content of the structural units derived from the epoxy-modified silicone B is 20 to 60 mass% relative to the total mass of the polymer E. 2. The thermosetting resin composition according to claim 1, wherein the weight average molecular weight of the polymer E is 3.0×10 ³ to 5.0×10 ⁴ . The thermosetting resin composition according to claim 1, further comprising a maleimide compound F1 and/or a cyanate ester compound F2. The thermosetting resin composition according to claim 1, wherein the content of the aluminum chelate complex D is 0.05 to 3 parts by mass per 100 parts by mass of the total resin solids contained in the thermosetting resin composition. The thermosetting resin composition according to claim 1, wherein the content of the polymer E is 5 to 50 parts by mass per 100 parts by mass of the total resin solids contained in the thermosetting resin composition. The thermosetting resin composition according to claim 1, further comprising an inorganic filler. Alkenylphenol A,
Epoxy-modified silicone B;
an epoxy compound C different from the epoxy-modified silicone B;
Aluminum chelate complex D;
A thermosetting resin composition comprising: The thermosetting resin composition according to claim 12, wherein the epoxy compound C comprises a naphthalene cresol novolac type epoxy resin and/or a naphthylene ether type epoxy resin. A cured product obtained by curing the thermosetting resin composition according to any one of claims 1 to 13. A substrate;
The thermosetting resin composition according to any one of claims 1 to 13, which is impregnated into or applied to the substrate;
A prepreg comprising: A resin sheet comprising the thermosetting resin composition according to any one of claims 1 to 13. A laminate comprising the prepreg according to claim 15 and/or a cured product obtained by curing the prepreg;
A metal foil disposed on one or both sides of the laminate;
A metal foil-clad laminate comprising: An insulating layer comprising a cured product obtained by curing the prepreg according to claim 15;
A conductor layer formed on a surface of the insulating layer;
A printed wiring board comprising: