JP2024154932A - 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 low thermal expansion properties. [Solution] A thermosetting resin composition containing a polymer E having 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 other than the epoxy-modified silicone B, and a hindered phenol compound D having an ester bond in the molecule. [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, semiconductor packages, which are widely used in electronic devices, communication devices, personal computers, etc., have become more functional and smaller, and 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 are becoming increasingly strict. Examples of properties required for such printed wiring boards include heat resistance, low thermal expansion, chemical resistance, and peel strength.

In light of this background, Patent Document 1 proposes that 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, be applied to prepregs, resin sheets, metal foil-clad laminates, and printed wiring boards.

International Publication No. 2020/022084

The technology described in Patent Document 1 is said to be capable of exhibiting excellent compatibility, low thermal expansion, and chemical resistance. On the other hand, in the application of laminates for semiconductor packages, there is an increasing demand for a reduction in the thermal expansion coefficient in the plane direction of the laminate (hereinafter also simply referred to as "thermal expansion coefficient"). Hereinafter, a low thermal expansion coefficient is also referred to as "excellent low thermal expansion." From the viewpoint of such low thermal expansion, even the technology described in Patent Document 1 still has room for improvement.

The present invention has been made in consideration of the above problems, 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 excellent low thermal expansion properties.

The present inventors have conducted extensive research to solve the above problems. As a result, they have found that the above problems can be solved by using a polymer E having a structural unit derived from an alkenylphenol, a structural unit derived from an epoxy-modified silicone, and a structural unit derived from an epoxy compound other than the epoxy-modified silicone in combination with a hindered phenol compound D having an ester bond in the molecule, and have completed the present invention.

That is, the present invention is as follows.
[1]
a polymer E having 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 other than the epoxy-modified silicone B;
and a hindered phenol compound D having an ester bond in the molecule,
Thermosetting resin composition.
[2]
The hindered phenol compound D has a pentaerythritol skeleton in the molecule.
The thermosetting resin composition according to [1].
[3]
The alkenylphenol A contains diallyl bisphenol and/or dipropenyl bisphenol.
The thermosetting resin composition according to [1] or [2].
[4]
The epoxy-modified silicone B contains an epoxy-modified silicone having an epoxy equivalent of 140 to 250 g/mol.
The thermosetting resin composition according to any one of [1] to [3].
[5]
the content of the structural units derived from the epoxy-modified silicone B is 20 to 60% by mass relative to the total mass of the polymer E;
The thermosetting resin composition according to any one of [1] to [4].
[6]
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 any one of [1] to [5].
[7]
Further comprising a cyanate ester compound F and/or a maleimide compound G;
The thermosetting resin composition according to any one of [1] to [6].
[8]
The content of the polymer E is 5 to 50% by mass based on 100% by mass of the resin solid content in the thermosetting resin composition.
The thermosetting resin composition according to any one of [1] to [7].
[9]
The content of the hindered phenol compound D is 1.0 to 10 mass% based on 100 mass% of the resin solid content in the thermosetting resin composition.
The thermosetting resin composition according to any one of [1] to [8].
[10]
The thermosetting resin composition according to any one of [1] to [9], further comprising an inorganic filler.
[11]
Alkenylphenol A,
Epoxy-modified silicone B;
an epoxy compound C other than the epoxy-modified silicone B;
and a hindered phenol compound D having an ester bond in the molecule,
Thermosetting resin composition.
[12]
A cured product obtained by curing the thermosetting resin composition according to any one of [1] to [11].
[13]
A substrate;
The thermosetting resin composition according to any one of [1] to [11], which is impregnated into or applied to the substrate;
A prepreg comprising:
[14]
[1] to [11], comprising the thermosetting resin composition according to any one of the above.
Resin sheet.
[15]
A laminate comprising the prepreg according to [13] 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:
[16]
[13] An insulating layer comprising a cured product obtained by curing the prepreg according to [13];
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 excellent low thermal expansion properties.

The following provides a detailed explanation of the embodiment of the present invention (hereinafter referred to as the "present embodiment"); however, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention.

Unless otherwise specified, the term "resin solids" used in this specification means the total content of polymer E and other resins in the thermosetting resin composition of this embodiment, and 100 parts by mass of resin solids means that the total content of polymer E and other resins is 100 parts by mass. Also, 100% by mass of resin solids means that the total content of polymer E and other resins in the thermosetting resin composition is 100% by mass.

1. Thermosetting resin composition The thermosetting resin composition according to the first aspect of this embodiment (hereinafter also referred to as the "first composition") contains a polymer E having a constituent unit derived from an alkenylphenol A, a constituent unit derived from an epoxy-modified silicone B, and a constituent unit derived from an epoxy compound C other than the epoxy-modified silicone B, and a hindered phenol compound D having an ester bond in the molecule. Since the first composition is configured in this way, it has excellent low thermal expansion properties.

The thermosetting resin composition according to the second aspect of this embodiment (hereinafter also referred to as the "second composition") contains an alkenylphenol A, an epoxy-modified silicone B, an epoxy compound C other than the epoxy-modified silicone B, and a hindered phenol compound D having an ester bond in the molecule. Since the second composition is configured in this way, it has excellent low thermal expansion properties. The second composition is distinguished from the first composition in that the presence of the polymer E is not specified in the composition.

Hereinafter, when referring to the "thermosetting resin composition of this embodiment" or the "thermosetting resin composition", it means both the "first composition" and the "second composition" unless otherwise specified.

The reason why the thermosetting resin composition of this embodiment has excellent low thermal expansion properties is not particularly limited, but is thought to be as follows. In general, the thermal expansion of a substance consists of the thermal expansion of the occupied volume and the thermal expansion of the free volume. The occupied volume is the volume based on the covalent bond distance or van der Waals distance, and the free volume is the volume generated by molecular motion.

In thermosetting resins, the molecules are cross-linked to form a three-dimensional network structure, which limits micro-Brownian motion in the rubbery state. Therefore, when transitioning from the rubbery state to the glassy state, the micro-Brownian motion is frozen in a state with a large free volume. As a result, the packing state of the molecular chains in the glassy state becomes loose, so the van der Waals distance between molecules tends to increase as the temperature increases, and it is thought that the glassy state shows a large thermal expansion coefficient.

The thermosetting resin composition of this embodiment contains a hindered phenol compound having an ester bond, and the bulkiness of the hindered phenol moiety increases the distance between crosslinked chains, decreasing the crosslink density, reducing the restriction of micro-Brownian motion in the rubber state, and the composition is frozen in a state with a smaller free volume when transitioning to a glassy state. Therefore, it is believed that in the glassy state, the van der Waals forces between molecular chains are strong, resulting in a smaller thermal expansion coefficient.

The hindered phenol compound has an ester bond in the molecule, which gives it excellent dispersibility between polymer chains, and is therefore believed to be able to achieve the above-mentioned effects.

Furthermore, when the hindered phenol compound has a pentaerythritol skeleton, the hindered phenol moiety further reduces the restriction of micro-Brownian motion in the glassy state due to its high flexibility and the density of the organic groups that cause steric hindrance, thereby suppressing thermal expansion in the glassy state and providing even better low thermal expansion properties.

The components of the thermosetting resin composition of this embodiment are described in detail below.

1.1. Polymer E
The polymer E is included in the first composition of this embodiment. The polymer E contains 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 the inclusion of "structural units derived from an alkenylphenol A", "structural units derived from an epoxy-modified silicone B", "structural units derived from an epoxy compound C", and "structural units 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 an alkenylphenol A, an epoxy-modified silicone B, an epoxy compound C, and, if necessary, a 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 first composition of this embodiment has excellent low thermal expansion properties by containing the polymer E.

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 the alkenylphenol A will also be referred to as constituent units A, B, C, and A', respectively.

1.1.1. 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.

The 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 more effectively and reliably achieving the effects of this embodiment, it is preferable that the alkenylphenol A has one or two structures in which one or more alkenyl groups are directly bonded to a phenolic aromatic ring, and it is preferable that the alkenylphenol A 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.

The content of structural unit A in polymer E is preferably 1 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 first 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 5 to 30% by mass, and even more preferably 10 to 20% by mass.

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 an epoxy-modified silicone having an epoxy equivalent of 140 to 250 g/mol. By containing an epoxy-modified silicone B having an epoxy equivalent within the above range, the balance between heat resistance and low thermal expansion tends to be further improved. 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.)

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.

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 first 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 30 to 60% by mass, and even more preferably 40 to 60% by mass.

From the viewpoint of achieving even better low thermal expansion and chemical resistance, the content of structural unit B is preferably 5.0 to 99 mass%, more preferably 10 to 95 mass%, even more preferably 40 to 90 mass%, and even more preferably 70 to 85 mass%, relative to 100 mass% of the total of structural units B and C.

The content of structural unit B1 derived from low equivalent weight epoxy-modified silicone B1 in polymer E is preferably 5 to 30 mass % relative to the total mass of polymer E, more preferably 7.5 to 25 mass %, and even more preferably 10 to 20 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 50 mass %, and even more preferably 30 to 40 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.

1.1.3. 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. Examples of the alkyl group include, but are not limited to, 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.

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.)

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 1 to 50 mass% relative to the total mass of polymer E. When the content of structural unit C is within the above range, the first 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 5 to 30 mass%, and more preferably 10 to 20 mass%.

The content of structural unit C is preferably 1 to 95 mass %, more preferably 5 to 90 mass %, even more preferably 10 to 60 mass %, and particularly preferably 15 to 30 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.

1.1.4. Phenolic compound A' other than alkenylphenol A
From the viewpoint of exhibiting even better chemical resistance, the thermosetting resin composition of the present embodiment preferably contains a phenolic compound A' other than alkenylphenol A. 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.

The content of structural unit A' in polymer E is preferably 5 to 45% by mass, based on the total mass of polymer E. By having the content of structural unit A' within the above range, the first composition tends to exhibit even better chemical resistance. From the same viewpoint, the content of structural unit A' is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass, based on the total mass of polymer E.

1.1.5. Weight average molecular weight 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 , as calculated using polystyrene standards by gel permeation chromatography. When the weight average molecular weight is 3.0×10 ³ or more, the first 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.

1.1.6. Alkenyl group equivalent The alkenyl group equivalent in the polymer E is preferably 300 to 1500 g/mol. When the alkenyl group equivalent is 300 g/mol or more, the cured product of the first composition tends to have a further reduced elastic modulus, 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 insulation reliability of the first 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.

1.1.7 Content of polymer E in first composition The content of polymer E in the first composition is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 30% by mass, based on 100% by mass of the resin solid content in the first composition. When the content is within the above range, the first composition tends to exhibit even better heat resistance, low thermal expansion property, chemical resistance, copper foil adhesion, and insulation reliability in a well-balanced manner.

The content of polymer E in the first composition is preferably 1.0 to 30 mass % relative to the total amount of the first composition, more preferably 3.0 to 20 mass %, and even more preferably 5.0 to 10 mass %. When the content is within the above range, the first composition tends to exhibit a good balance of even better heat resistance, low thermal expansion, chemical resistance, copper foil adhesion, and insulation reliability.

1.1.8. Method for Producing Polymer E The polymer E can be obtained, for example, by reacting an alkenylphenol A, an epoxy-modified silicone B, an epoxy compound C, and, if necessary, a phenol compound A' in the presence of a polymerization catalyst. 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 the epoxy compound C and the hydroxyl group of the alkenylphenol A, and the addition reaction between the hydroxyl group of the obtained addition reaction product and the epoxy groups of the epoxy-modified silicone B and the epoxy compound C proceed, thereby obtaining the polymer E.

The polymerization catalyst 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 the polymerization catalyst (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 the alkenylphenol A, the epoxy-modified silicone B, the epoxy compound C, and the phenol compound A'. From the viewpoint of increasing the weight-average molecular weight of the polymer E, the amount of the polymerization catalyst 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 is, 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.

1.2. Hindered phenol compound D
The hindered phenol compound D is a hindered phenol compound having an ester bond in the molecule. The thermosetting resin composition of the present embodiment can achieve low thermal expansion by containing the hindered phenol compound D. From the viewpoint of increasing steric hindrance, the hindered phenol compound D preferably has a pentaerythritol skeleton in the molecule.

The hindered phenol compound D of the present embodiment is not particularly limited as long as it has an ester bond in the molecule, and examples thereof include compounds represented by the following formula (d1).
(In the above formula (d1), R ₁ is a group having steric hindrance, R ₂ is a divalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and R ₃ is an organic group having 1 to 20 carbon atoms which may have a substituent. m is an integer of 1 to 3, and n is an integer of 2 to 10.)

In the above formula (d1), the sterically hindered group of R ₁ is not particularly limited, but examples thereof include a t-butyl group and an isopropyl group. Among these, a t-butyl group is preferred from the viewpoint of enhancing steric hindrance. In addition, the substitution position of R ₁ on the benzene ring is preferably the position adjacent to the hydroxyl group.

R ₂ is preferably a divalent hydrocarbon group having 1 to 5 carbon atoms, more preferably a hydrocarbon group having 1 to 3 carbon atoms. The hydrocarbon group in R ₂ may or may not have a branched chain. It is preferable that it has no substituent. R ₂ is more preferably an alkylene group having 1 to 5 carbon atoms, and even more preferably an alkylene group having 1 to 3 carbon atoms. The alkylene group may or may not have a branched chain. It is preferable that it has no substituent.

_R3 is preferably a hydrocarbon group having 1 to 15 carbon atoms which may contain a heteroatom, more preferably having 3 to 15 carbon atoms. When _R3 contains a heteroatom, the heteroatom is preferably an oxygen atom. It is preferable that R3 has no substituent. In addition, it is more preferable that _R3 has a skeleton of the hydrocarbon portion of pentaerythritol.

From the viewpoint of increasing steric hindrance, m is preferably 2 or more. Similarly, from the viewpoint of increasing steric hindrance, n is preferably 2 or more.

Specific examples of the hindered phenol compound D of the present embodiment include, but are not limited to, the following compounds d11 and d12.

Compound d11 and compound d12 are not particularly limited, but may be synthesized by a conventionally known method, or a commercially available product may be used. The commercially available product of compound d11 is not particularly limited, but for example, "Adeka STAB AO-60" (manufactured by ADEKA CORPORATION, hindered phenol compound) can be used, and the commercially available product of compound d12 is not particularly limited, but for example, "Adeka STAB AO-80" (manufactured by ADEKA CORPORATION, hindered phenol compound) can be used.

The content of the hindered phenol compound D is preferably 1.0 to 10 mass%, more preferably 2.0 to 8.0 mass%, and even more preferably 4.0 to 6.0 mass%, relative to 100 mass% of the resin solid content in the thermosetting resin composition. By having the content of the hindered phenol compound D in the above range, the composition tends to have even better low thermal expansion properties.

The content of the hindered phenol compound D is preferably 0.1 to 10 mass %, more preferably 0.5 to 5 mass %, and even more preferably 1.0 to 3.0 mass %, relative to the total amount of the thermosetting resin composition.

1.3. Other Resins In the thermosetting resin composition of this embodiment, the first composition may contain a resin other than the polymer E (hereinafter, also referred to as "other resins") from the viewpoint of further improving the heat resistance, low thermal expansion, chemical resistance, and copper foil adhesion. The other resin is not particularly limited, but it is preferable to further contain at least one compound selected from the group consisting of epoxy compound C, cyanate ester compound F, maleimide compound G, phenol compound A' other than the alkenylphenol A, and alkenyl-substituted nadiimide compound H, and it is more preferable to contain cyanate ester compound F and/or maleimide compound G. The epoxy compound C is the same as the epoxy compound C that can constitute the structural unit of the polymer E. The phenol compound A' is the same as the phenol compound A' that can constitute the structural unit of the polymer E. In addition, the second composition may also contain the above-mentioned other resins from the viewpoint of further improving the heat resistance, low thermal expansion, chemical resistance, and copper foil adhesion.

The content of the other resin in the thermosetting resin composition of this embodiment is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, and even more preferably 70 to 85% by mass, based on 100% by mass of the resin solids.

The content of the other resin in the thermosetting resin composition of this embodiment is preferably 10 to 50 mass % relative to the total amount of the thermosetting resin composition, more preferably 15 to 45 mass %, and even more preferably 20 to 40 mass %.

1.3.1. Cyanate ester compound F
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 F. The cyanate ester compound F 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 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 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 F 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 F 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 may be produced according to known methods. Specific production methods include, for example, those described in JP 2017-195334 A (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 F is preferably 5 to 50 mass% relative to 100 mass% of the resin solids, more preferably 10 to 40 mass%, and even more preferably 10 to 30 mass%.

1.3.2. Maleimide compound G
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 G. The maleimide compound G is not particularly limited as long as it is a compound having one or more maleimide groups in one molecule, and 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 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 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, maleimide compounds represented by formula (3), and maleimide compounds 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 G may be a commercially available product or a product produced by a known method. Commercially available maleimide compounds include "BMI-70", "BMI-80", and "BMI-1000P" manufactured by K.I. Kasei 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).

From the viewpoint of further improving low thermal expansion and chemical resistance, the content of maleimide compound G is preferably 5 to 50 mass %, more preferably 10 to 45 mass %, and even more preferably 15 to 35 mass %, relative to 100 mass % of the resin solid content.

1.3.3. Alkenyl-substituted nadiimide compound H
From the viewpoint of further improving heat resistance, the thermosetting resin composition of the present embodiment preferably contains an alkenyl-substituted nadimide compound H. The alkenyl-substituted nadimide compound H is not particularly limited as long as it is a compound having one or more alkenyl-substituted nadimide 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 H 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.

1.4. Other Components The thermosetting resin composition of the present embodiment may contain other components in addition to the polymer E and other resins, as long as the effects of the present invention are not impaired. Examples of other components include, but are not limited to, inorganic fillers, flame retardants, wetting and dispersing agents, silane coupling agents, and solvents.

1.4.1. 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 properties, 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 resin solids.

1.4.2 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., p-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 1.0 to 10 parts by mass per 100 parts by mass of resin solids.

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 to 5.0 parts by mass per 100 parts by mass of resin solids.

The thermosetting resin composition of the present embodiment may further contain a flame retardant. By containing a flame retardant, the heat resistance of the thermosetting resin composition of the present embodiment tends to be further improved.

As the flame retardant, a conventionally known flame retardant can be used, for example, PX-200, a phosphoric acid ester compound manufactured by Daihachi Chemical Industry Co., Ltd.

The amount of flame retardant contained is not particularly limited, but is preferably 1.0 to 10 parts by mass per 100 parts by mass of resin solids.

1.4.5 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 reduced, 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.

2. Applications As described above, the thermosetting resin composition of the present embodiment can exhibit excellent heat resistance and low thermal expansion. Therefore, the thermosetting resin composition of the present embodiment is suitably used for metal foil-clad laminates and printed wiring boards. The thermosetting resin composition of the present embodiment can be applied to the above-mentioned applications by curing.

2.1. Cured product The cured product is obtained by curing the thermosetting resin composition of the present embodiment. The method for producing the cured product is not particularly limited, but for example, the thermosetting resin composition of the present embodiment is melted or dissolved in a solvent, poured into a mold, and cured under normal conditions using heat, light, or the like. In the case of thermal curing, the curing temperature is preferably within the range of 120 to 300°C from the viewpoint of efficient curing and preventing deterioration of the obtained cured product.

In the cured product of the first composition, 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, even more preferably a unit derived from the compound represented by the above formula (b2) (compound b2), and even 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).
Further, in the thermosetting resin composition, the value of cyanate equivalent/epoxy equivalent is preferably less than 0.8. The cyanate equivalent/epoxy equivalent (functional group equivalent ratio) is the ratio of the equivalent of the cyanate group in the cyanate ester compound that can be contained in the thermosetting resin composition to the equivalent of the epoxy group in the "epoxy compound C that exists separately from the structural unit C in the polymer E" that can be contained in the thermosetting resin composition, and is calculated by the following calculation formula (1). In this embodiment, it is also possible to use two or more types of either the cyanate ester compound or the epoxy compound, but in that case, the method of calculating the functional group equivalent ratio is to calculate the number of functional groups (i.e., the equivalent of the cyanate group and the equivalent of the epoxy group) for each component in each of the cyanate ester compound and the epoxy compound, and to calculate the equivalent of the total cyanate group and the equivalent of the total epoxy group by adding up the values. The functional group equivalent ratio is the value obtained by dividing the equivalent of the total cyanate group by the equivalent of the total epoxy group. The number of functional groups is the value obtained by dividing the parts by mass of a component by the functional group equivalent of that component.
Calculation formula (1): Functional group equivalent ratio=(parts by mass of cyanate ester compound in thermosetting resin composition/functional group equivalent of cyanate ester compound)/(parts by mass of epoxy compound in thermosetting resin composition/functional group equivalent of epoxy compound)

2.2. Resin sheet The resin sheet of this embodiment contains the thermosetting resin composition of this embodiment. The resin sheet has a support and a resin layer arranged on one or both sides of the support, and it is preferable that the resin layer contains the thermosetting resin composition of this embodiment. The resin sheet is not particularly limited, but may be formed, for example, by applying the thermosetting resin composition of this embodiment to one or both sides of the support. The resin sheet can be produced, for example, by directly applying the thermosetting resin composition of this embodiment to a support such as a metal foil or film and drying it.

The support is not particularly limited, but may be any known material used in various printed wiring board materials, and is preferably a resin film or metal foil. Examples of resin films and metal foils include resin films such as polyimide film, polyamide film, polyester film, polyethylene terephthalate (PET) film, polybutylene terephthalate (PBT) film, polypropylene (PP) film, and polyethylene (PE) film, and metal foils such as aluminum foil, copper foil, and gold foil. Of these, electrolytic copper foil and PET film are preferred as the support.

The resin sheet is not particularly limited, but can be obtained, for example, by applying the thermosetting resin composition of this embodiment to a support and then semi-curing (B-stage). A method for producing a resin sheet is generally preferred that produces a composite of a B-stage resin and a support. Specifically, for example, a method can be used in which the thermosetting resin composition is applied to a support such as copper foil, and then semi-cured by heating in a dryer at 100 to 200°C for 1 to 60 minutes to produce a resin sheet. The amount of the thermosetting resin composition attached to the support is preferably in the range of 1.0 to 300 μm in terms of the resin thickness of the resin sheet. The resin sheet can be used as a build-up material for printed wiring boards.

2.3. 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, it has excellent heat resistance and low thermal expansion when applied to a metal foil-clad laminate and a printed wiring board.

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.

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

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.

2.4 Metal foil-clad 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.

2.5 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 a 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.

1. Preparation of thermosetting resin composition 1.1. Synthesis of polymer E In a three-neck flask equipped with a thermometer and a Dimroth gauge, 3.0 parts by mass of DABPA (manufactured by Daiwa Chemical Industry Co., Ltd., diallyl bisphenol A), 3.0 parts by mass of X-22-163 (manufactured by Shin-Etsu Chemical Co., Ltd., epoxy-modified silicone, functional group equivalent 200 g/mol), 7.0 parts by mass of KF-105 (manufactured by Shin-Etsu Chemical Co., Ltd., epoxy-modified silicone, functional group equivalent 490 g/mol), 3.0 parts by mass of YL-6121H (manufactured by Mitsubishi Chemical Corporation, biphenyl-type epoxy resin), 4.0 parts by mass of BCF (manufactured by Osaka Gas Chemical Co., Ltd., biscresol fluorene), and 0.2 parts by mass of TBZ (manufactured by Shikoku Chemical Industry Co., Ltd., imidazole catalyst) were added, and DOWANOL as a solvent was added. 20.2 parts by mass of PMA (propylene glycol monomethyl ether acetate, manufactured by Dow Chemical Japan) was added, and the mixture was heated and stirred in an oil bath to 120° C. After confirming that the raw materials were dissolved in the solvent, the mixture was heated to 140° C., stirred for 5 hours, and cooled to obtain a phenoxy polymer solution (solid content 50% by mass) (polymer production step).

The resulting phenoxy polymer contained, relative to 100% by mass of phenoxy polymer, 15% by mass of structural units derived from DABPA, 15% by mass of structural units derived from X-22-163, 35% by mass of structural units derived from KF-105, 15% by mass of structural units derived from YL-6121H, and 20% by mass of structural units derived from BCF.

Note that DABPA corresponds to "alkenylphenol A", X-22-163 and KF-105 correspond to "epoxy-modified silicone B", YL-6121H corresponds to "epoxy compound C", and BCF corresponds to "phenol compound A'". The obtained phenoxy polymer corresponds to polymer E, which has structural units derived from alkenylphenol A, structural units derived from epoxy-modified silicone B, structural units derived from epoxy compound C, and structural units derived from phenol compound A'.

[Method for measuring weight average molecular weight Mw]
The weight average molecular weight Mw of the polymer E obtained as described above was measured as follows. 20 μL of a solution obtained by dissolving 0.5 g of polymer E in 4.5 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, 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), were used, THF (solvent) was used as the mobile phase, the flow rate was set to 1 mL/min, and the detector was RID-10A. The weight average molecular weight Mw was determined by the GPC method using standard polystyrene as the standard substance. The weight average molecular weight Mw of polymer E measured as described above was 12,000.

1.2. Preparation of thermosetting resin composition (Example 1)
The following compounds were added to 20 parts by mass of the phenoxy polymer obtained above: 2.0 parts by mass of AO-60 (manufactured by ADEKA CORPORATION, hindered phenol compound, having an ester bond and having a pentaerythritol skeleton), 18 parts by mass of SNCN (SN495V-CN obtained in Synthesis Example 1 described later), 18 parts by mass of BMI-2300 (manufactured by Daiwa Kasei Kogyo Co., Ltd., novolac-type maleimide compound), 7.0 parts by mass of BMI-70 (manufactured by Daiwa Kasei Kogyo Co., Ltd., bismaleimide compound), HP-6000 (manufactured by DIC Corporation, nano- A varnish was obtained by mixing 37 parts by mass of phthalene cresol novolac type epoxy resin (functional group equivalent: 250 g/mol), 150 parts by mass of SC-2050MB (Admatechs Co., Ltd., slurry silica), 5.0 parts by mass of KBM-403 (Shin-Etsu Chemical Co., Ltd., silane coupling agent), 1.0 parts by mass of BYK-161 (BYK Japan Co., Ltd., DISPERBYK-161), and 5.0 parts by mass of PX-200 (Daihachi Chemical Industry Co., Ltd., phosphoric acid ester compound) (varnish production step). This varnish was impregnated and coated on an S-glass woven fabric (thickness: 100 μm), and dried by heating at 165 ° C. for 5 minutes to obtain a prepreg having a thermosetting resin composition solid content (including filler) of 58.2% by volume (prepreg production step).

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 AO-60 (manufactured by ADEKA CORPORATION, hindered phenol compound, having ester bonds, and having a pentaerythritol skeleton) was changed from 2.0 parts by mass to 5.0 parts by mass.

Example 3
A prepreg having 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 other words, in the varnish production step, 5.0 parts by mass of AO-80 (manufactured by ADEKA Corporation, hindered phenol compound, with ester bonds, and with pentaerythritol skeleton) was used instead of 2.0 parts by mass of AO-60 (manufactured by ADEKA Corporation, hindered phenol compound, with ester bonds, and with pentaerythritol skeleton).

(Comparative Example 1)
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 other words, the varnish production step was changed so that AO-60 (manufactured by ADEKA CORPORATION, hindered phenol compound, having ester bonds, and having a pentaerythritol skeleton) was not included.

(Comparative Example 2)
A prepreg having 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 other words, in the varnish production step, 5.0 parts by mass of AO-20 (manufactured by ADEKA Corporation, hindered phenol compound, no ester bond, no pentaerythritol skeleton) was used instead of 2.0 parts by mass of AO-60 (manufactured by ADEKA Corporation, hindered phenol compound, with ester bond, with pentaerythritol skeleton).

(Comparative Example 3)
A prepreg having 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 other words, in the varnish production step, 5.0 parts by mass of AO-330 (manufactured by ADEKA Corporation, hindered phenol compound, no ester bond, no pentaerythritol skeleton) was used instead of 2.0 parts by mass of AO-60 (manufactured by ADEKA Corporation, hindered phenol compound, with ester bond, with pentaerythritol skeleton).

(Comparative Example 4)
A prepreg having a thermosetting resin composition solids content (including filler) of 58.2 volume % was obtained in the same manner as in Example 1, except for the following points. That is, in the varnish production step, the composition was changed so as not to contain polymer E, the composition was changed so as not to contain AO-60 (manufactured by ADEKA Corporation, hindered phenol compound, with ester bond, with pentaerythritol skeleton), the content of SNCN (SN495V-CN obtained by Synthesis Example 1 described later) was changed from 18 parts by mass to 23 parts by mass, the content of BMI-2300 (manufactured by Daiwa Kasei Kogyo Co., Ltd., novolac-type maleimide compound) was changed from 18 parts by mass to 23 parts by mass, the content of BMI-70 (manufactured by Daiwa Kasei Kogyo Co., Ltd., bismaleimide compound) was changed from 7.0 parts by mass to 10 parts by mass, and the content of HP-6000 (manufactured by DIC Corporation, naphthalene cresol novolac-type epoxy resin, functional group equivalent 250 g/mol) was changed from 37 parts by mass to 44 parts by mass.

(Comparative Example 5)
A prepreg having a thermosetting resin composition solids content (including filler) of 58.2% by volume was obtained in the same manner as in Comparative Example 4, except for the following: The varnish production step was changed to include 5.0 parts by mass of AO-60 (manufactured by ADEKA CORPORATION, hindered phenol compound, having ester bonds, and having a pentaerythritol skeleton).

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.)

2. Evaluation 2.1. Preparation of metal foil-clad laminate Two prepregs obtained in each of Examples 1 to 3 and Comparative Examples 1 to 5 were stacked, and electrolytic copper foils (3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 12 μm were placed on top and bottom, and laminate molding was performed at a pressure of 30 kgf/cm ² and a temperature of 230° C. for 100 minutes to obtain a copper foil-clad laminate including an insulating layer having a thickness of 0.22 mm as a metal foil-clad laminate. The properties of the obtained copper foil-clad laminate were evaluated by the method shown below. The evaluation results are shown in Table 1.

2.2. Tg (glass transition temperature)
The obtained copper foil-clad laminate 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. The loss modulus E'' of this measurement sample 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).

2.3. 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 laminate. 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, the temperature was raised from 30 ° C to 260 ° C at 10 ° C per minute using a thermal expansion measuring device (horizontal dilatometer DIL L75 PT manufactured by Linseis Co., Ltd.), 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 used as the linear thermal expansion coefficient shown in Table 1. The obtained linear thermal expansion coefficient was evaluated according to the following evaluation criteria.
<Evaluation criteria>
⊚: The linear thermal expansion coefficient is less than 5.5 ppm/°C.
A: The linear thermal expansion coefficient is 5.5 ppm/°C or more and less than 6.0 ppm/°C.
Δ: The linear thermal expansion coefficient is 6.0 ppm/° C. or more and less than 10.0 ppm/° C.
×: The linear thermal expansion coefficient is 10.0 ppm/° C. or more.

3. Discussion From Table 1 above, it can be seen that Examples 1 to 3 have a better low thermal expansion property than Comparative Examples 1 to 5. It should be noted that, while Examples 1 to 3 use hindered phenol compound D, Comparative Examples 2 and 3 use hindered phenol compounds other than hindered phenol compound D. It is therefore presumed that the inclusion of hindered phenol compound D in the thermosetting resin composition results in excellent low thermal expansion property (however, this is not intended to limit the cause).

The present invention has industrial applicability as a thermosetting resin composition used as a material for prepregs, resin sheets, metal foil-clad laminates, printed wiring boards, etc.

Claims (16)

a polymer E having 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 other than the epoxy-modified silicone B;
and a hindered phenol compound D having an ester bond in the molecule,
Thermosetting resin composition. The hindered phenol compound D has a pentaerythritol skeleton in the molecule.
The thermosetting resin composition according to claim 1 . The alkenylphenol A contains diallyl bisphenol and/or dipropenyl bisphenol.
The thermosetting resin composition according to claim 1 . The epoxy-modified silicone B contains an epoxy-modified silicone having an epoxy equivalent of 140 to 250 g/mol.
The thermosetting resin composition according to claim 1 . the content of the structural units derived from the epoxy-modified silicone B is 20 to 60% by mass relative to the total mass of the polymer E;
The thermosetting resin composition according to claim 1 . 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 cyanate ester compound F and/or a maleimide compound G;
The thermosetting resin composition according to claim 1 . The content of the polymer E is 5 to 50% by mass based on 100% by mass of the resin solid content in the thermosetting resin composition.
The thermosetting resin composition according to claim 1 . The content of the hindered phenol compound D is 1.0 to 10 mass% based on 100 mass% of the resin solid content in the thermosetting resin composition.
The thermosetting resin composition according to claim 1 . The thermosetting resin composition according to claim 1, further comprising an inorganic filler. Alkenylphenol A,
Epoxy-modified silicone B;
an epoxy compound C other than the epoxy-modified silicone B;
and a hindered phenol compound D having an ester bond in the molecule,
Thermosetting resin composition. A cured product obtained by curing the thermosetting resin composition according to any one of claims 1 to 11. A substrate;
The thermosetting resin composition according to any one of claims 1 to 11, which is impregnated or applied to the substrate;
A prepreg comprising: The thermosetting resin composition according to any one of claims 1 to 11,
Resin sheet. A laminate comprising the prepreg according to claim 13 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 13;
A conductor layer formed on a surface of the insulating layer;
A printed wiring board comprising: