JP7127414B2 - Thermosetting resin composition, prepreg, metal foil with resin, laminate, printed wiring board and semiconductor package - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermosetting resin composition, a prepreg, a resin-coated metal foil, a laminate, a printed wiring board, and a semiconductor package.

Heat resistance, electrical insulation, long-term reliability, component connection reliability, and the like are required for wiring board materials used in high-performance printed wiring boards.
Further, in a substrate on which ceramic components are mounted, there are major problems such as a difference in coefficient of thermal expansion between the ceramic components and the substrate, and deterioration in component connection reliability due to external impact. As a solution to this problem, stress relaxation from the substrate side has also been proposed. In order to solve these problems, a resin composition containing a thermosetting resin and a thermoplastic resin such as an acrylic polymer and a terminal-modified polyethersulfone has been proposed (for example, Patent Documents 1 to 3 reference).

JP-A-8-283535 Japanese Patent Application Laid-Open No. 2002-134907 Japanese Patent Application Laid-Open No. 2002-371190

However, in recent years, printed wiring boards have been increasingly used in harsh environments such as high-temperature environments. It became clear that it is difficult to secure the adhesive strength of

The present invention has been made in view of the above circumstances, and provides a thermosetting resin composition having sufficient heat resistance and low elastic modulus, and having high adhesive strength with metal foil under normal temperature and high temperature environments. , to provide a prepreg, a resin-coated metal foil, a laminate, a printed wiring board, and a semiconductor package using the thermosetting resin composition.

As a result of intensive studies aimed at solving the above problems, the present inventors have found that the above problems can be solved by the present invention described below, and have completed the present invention.

（式中、Ｒ^１は、水素原子、置換基を有していてもよい炭素数１～９の脂肪族炭化水素基、置換基を有していてもよい環形成原子数５～１５の芳香族炭化水素基、又は、前記脂肪族炭化水素基と前記芳香族炭化水素基との組み合わせを示し、Ｒ^２は、炭素数１０～２５の鎖状脂肪族炭化水素基を示す。Ｘは、水素原子、ヒドロキシ基又はヒドロキシメチル基である。）
［３］前記（Ａ１）成分の含有量が、熱硬化性樹脂組成物の樹脂成分総量１００質量部に対して、０．１～４０質量部である、上記［１］又は［２］に記載の熱硬化性樹脂組成物。
［４］前記（Ｂ）成分が、エポキシ樹脂、シアネート樹脂、ビスマレイミド系化合物、ビスマレイミド系化合物とジアミン化合物との付加重合物、イソシアネート樹脂、トリアリルイソシアヌレート樹脂、トリアリルシアヌレート樹脂及びビニル基含有ポリオレフィン樹脂からなる群から選択される１種以上である、上記［１］～［３］のいずれかに記載の熱硬化性樹脂組成物。
［５］（Ｃ）アクリル系ポリマーが、下記一般式（ｃ１）で表される構造単位（ｃ１）、下記一般式（ｃ２）で表される構造単位（ｃ２）、下記一般式（ｃ３）で表される構造単位（ｃ３）及び下記一般式（ｃ４）で表される構造単位（ｃ４）を含むものである、上記［１］～［４］のいずれかに記載の熱硬化性樹脂組成物。

（Ｒ^ｃ１は水素原子又はメチル基を示し、Ｒ^ｃ２は炭素数１～３の炭化水素基を示す。）

（Ｒ^ｃ３は水素原子又はメチル基を示し、Ｒ^ｃ４は脂環式炭化水素基を含む炭素数５～２２の炭化水素基を示す。）

（Ｒ^ｃ５は水素原子又はメチル基を示し、Ｒ^ｃ６は炭素数４～１０の鎖状炭化水素基を示す。）

（Ｒ^ｃ７は水素原子又は炭素数１～３のアルキル基を示し、Ｚは、ヒドロキシ基、又は、カルボキシ基、ヒドロキシ基、酸無水物基、アミノ基、アミド基及びエポキシ基からなる群から選択される１種以上の官能基を含む置換基を示す。）
［６］前記（Ｃ）成分中における前記構造単位（ｃ１）の含有量が１～６０質量％、前記構造単位（ｃ２）の含有量が１～２０質量％、前記構造単位（ｃ３）の含有量が５～９０質量％、前記構造単位（ｃ４）の含有量が１～２０質量％である、上記［５］に記載の熱硬化性樹脂組成物。
［７］更に、（Ａ２）鎖状脂肪族炭化水素基と環状脂肪族炭化水素基との組み合わせである炭素数が１０～２５の脂肪族炭化水素基を有するフェノール系樹脂を含有する、上記［１］～［６］のいずれかに記載の熱硬化性樹脂組成物。
［８］前記（Ａ１）成分と前記（Ａ２）成分との含有量比〔（Ａ１）成分／（Ａ２）成分〕が、質量基準で、０．１～１である、上記［７］に記載の熱硬化性樹脂組成物。
［９］前記（Ｃ）成分の含有量が、熱硬化性樹脂組成物の樹脂成分総量１００質量部に対して、５～５０質量部である、上記［１］～［８］のいずれかに記載の熱硬化性樹脂組成物。
［１０］硬化物が相分離構造を有さない、上記［１］～［９］のいずれかに記載の熱硬化性樹脂組成物。
［１１］上記［１］～［１０］のいずれかに記載の熱硬化性樹脂組成物を含有してなるプリプレグ。
［１２］上記［１］～［１０］のいずれかに記載の熱硬化性樹脂組成物と金属箔とを積層してなる、樹脂付き金属箔。
［１３］上記［１１］に記載のプリプレグ又は上記［１２］に記載の樹脂付き金属箔を含有してなる積層体。
［１４］上記［１３］に記載の積層体を含有してなる、プリント配線板。
［１５］上記［１４］に記載のプリント配線板を含有してなる、半導体パッケージ。 That is, the present invention relates to the following [1] to [15].
[1] (A) a phenolic resin,
A thermosetting resin composition containing (B) a thermosetting resin and (C) an acrylic polymer,
A thermosetting resin composition in which the component (A) contains (A1) a phenolic resin having a chain aliphatic hydrocarbon group with 10 to 25 carbon atoms.
[2] The thermosetting according to [1] above, wherein the component (A1) contains a structural unit derived from the following general formula (1) and a structural unit derived from the following general formula (2) Resin composition.

(In the formula, R ¹ is a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 9 carbon atoms, an optionally substituted aromatic group having 5 to 15 ring atoms R ² represents a chain aliphatic hydrocarbon group having 10 to 25 carbon atoms, and X represents hydrogen. atom, hydroxy group or hydroxymethyl group.)
[3] The above [1] or [2], wherein the content of the component (A1) is 0.1 to 40 parts by mass with respect to 100 parts by mass of the total resin component of the thermosetting resin composition. thermosetting resin composition.
[4] Component (B) is an epoxy resin, a cyanate resin, a bismaleimide compound, an addition polymer of a bismaleimide compound and a diamine compound, an isocyanate resin, a triallyl isocyanurate resin, a triallyl cyanurate resin, and a vinyl The thermosetting resin composition according to any one of [1] to [3] above, which is at least one selected from the group consisting of group-containing polyolefin resins.
[5] (C) The acrylic polymer has a structural unit (c1) represented by the following general formula (c1), a structural unit (c2) represented by the following general formula (c2), and a structural unit (c3) represented by the following general formula (c3). The thermosetting resin composition according to any one of [1] to [4], which contains a structural unit (c3) represented by the following general formula (c4) and a structural unit (c4) represented by the following general formula (c4).

(R ^c1 represents a hydrogen atom or a methyl group, and R ^c2 represents a hydrocarbon group having 1 to 3 carbon atoms.)

(R ^c3 represents a hydrogen atom or a methyl group, and R ^c4 represents a hydrocarbon group having 5 to 22 carbon atoms including an alicyclic hydrocarbon group.)

(R ^c5 represents a hydrogen atom or a methyl group, and R ^c6 represents a chain hydrocarbon group having 4 to 10 carbon atoms.)

(R ^c7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Z is selected from the group consisting of a hydroxy group, a carboxy group, a hydroxy group, an acid anhydride group, an amino group, an amide group and an epoxy group. indicates a substituent containing one or more functional groups that are
[6] The content of the structural unit (c1) in the component (C) is 1 to 60% by mass, the content of the structural unit (c2) is 1 to 20% by mass, and the structural unit (c3) is contained. The thermosetting resin composition according to [5] above, wherein the amount is 5 to 90% by mass and the content of the structural unit (c4) is 1 to 20% by mass.
[7] Further, (A2) the above [ 1] The thermosetting resin composition according to any one of [6].
[8] The above [7], wherein the content ratio of the (A1) component and the (A2) component [(A1) component/(A2) component] is 0.1 to 1 on a mass basis. thermosetting resin composition.
[9] Any one of the above [1] to [8], wherein the content of the component (C) is 5 to 50 parts by mass with respect to 100 parts by mass of the total resin component of the thermosetting resin composition. A thermosetting resin composition as described.
[10] The thermosetting resin composition according to any one of [1] to [9] above, wherein the cured product does not have a phase separation structure.
[11] A prepreg containing the thermosetting resin composition according to any one of [1] to [10] above.
[12] A resin-coated metal foil obtained by laminating the thermosetting resin composition according to any one of [1] to [10] above and a metal foil.
[13] A laminate comprising the prepreg described in [11] above or the resin-coated metal foil described in [12] above.
[14] A printed wiring board comprising the laminate according to [13] above.
[15] A semiconductor package comprising the printed wiring board according to [14] above.

According to the present invention, a thermosetting resin composition having sufficient heat resistance and low elastic modulus and having high adhesive strength with a metal foil under normal temperature environment and high temperature environment, and the thermosetting resin composition A prepreg, a resin-coated metal foil, a laminate, a printed wiring board, and a semiconductor package can be provided.

An embodiment of the present invention will be described in detail below, but the present invention is not limited to the following embodiment.
In the numerical ranges described herein, the upper or lower limits of the numerical ranges may be replaced with the values shown in the examples. Also, the lower and upper limits of a numerical range can be arbitrarily combined with the lower and upper limits of other numerical ranges, respectively.
In addition, each component and material exemplified in this specification may be used alone or in combination of two or more unless otherwise specified. As used herein, the content of each component in the composition refers to the total amount of the multiple substances present in the composition when there are multiple substances corresponding to each component in the composition, unless otherwise specified. means
Furthermore, when the exemplified and preferred aspects are a set of options, any number of options can be extracted from the set, and the extracted options can be explained elsewhere. It can also be combined arbitrarily with the mode to do.
Embodiments in which the items described in this specification are combined arbitrarily are also included in the present invention.
In the present embodiment, "(meth)acryl" means one or more selected from the group consisting of "acryl" and "methacryl", and the same applies to other similar terms.
In this embodiment, normal temperature is typically 25°C, and high temperature is typically 125°C.

[Thermosetting resin composition]
The thermosetting resin composition of this embodiment is
(A) a phenolic resin (hereinafter also referred to as "(A) component"),
(B) thermosetting resin (hereinafter also referred to as "(B) component"), and (C) acrylic polymer (hereinafter also referred to as "(C) component")
wherein the (A) component is (A1) a phenolic resin having a chain aliphatic hydrocarbon group having 10 to 25 carbon atoms (hereinafter, “(A1) component” It is a thermosetting resin composition containing.
By having the above configuration, the thermosetting resin composition of the present embodiment has sufficient heat resistance and low elastic modulus, and has high adhesive strength with metal foil.
In addition to the (B) component, which is a thermosetting resin, the thermosetting resin composition of the present embodiment contains a (A1) component that has both thermosetting properties and low elasticity, and a (C) component, While achieving both high heat resistance and low elasticity, the cured product has excellent high elongation. By improving the high elongation, the stress at the bonding interface between the thermosetting resin composition and the metal foil, which is generated by the application of heat history, is effectively relieved, so that a high bonding strength with the metal foil is achieved. presumed to have been possible. Each component contained in the thermosetting resin composition of the present embodiment will be described below.

[(A) Phenolic resin]
(A) the phenolic resin contains (A1) a phenolic resin having a chain aliphatic hydrocarbon group having 10 to 25 carbon atoms, and (A2) a chain aliphatic hydrocarbon group and a cyclic It preferably contains a phenolic resin having an aliphatic hydrocarbon group with 10 to 25 carbon atoms in combination with an aliphatic hydrocarbon group (hereinafter also referred to as "component (A2)").
Hereinafter, the chain aliphatic hydrocarbon group having 10 to 25 carbon atoms that the component (A1) has is referred to as "hydrocarbon group a1", and the chain aliphatic hydrocarbon group and the cycloaliphatic hydrocarbon group that the component (A2) has The aliphatic hydrocarbon group having 10 to 25 carbon atoms which is a combination of is sometimes referred to as "hydrocarbon group a2".
In the present specification, the term "chain" means linear or branched.

The number of carbon atoms in the hydrocarbon group a1 of component (A1) is preferably 10 to 20, more preferably 12 to 20, still more preferably 12 to 18, even more preferably 14 to 18, particularly preferably 14 to 16, 15 is most preferred.
The number of carbon atoms in the hydrocarbon group a2 of component (A2) is preferably 10-18, more preferably 10-15, even more preferably 10-13, particularly preferably 10-12, and most preferably 11.
When the number of carbon atoms in the hydrocarbon groups a1 and a2 is within the above range, the obtained cured product has both high heat resistance and low elasticity, and has excellent high elongation.

The hydrocarbon groups a1 and a2 may be saturated aliphatic hydrocarbon groups or unsaturated aliphatic hydrocarbon groups. The number of unsaturated bonds possessed by the unsaturated aliphatic hydrocarbon group may be 1, may be 2 or more, and usually may be 5 or less, or 3 It may be below.

(A) As the phenolic resin, a component (A1) having a saturated aliphatic hydrocarbon group as the hydrocarbon group a1 and a component (A1) having an unsaturated aliphatic hydrocarbon group as the hydrocarbon group a1 are used in combination. is also preferred. When these are used together, the mass ratio of the component (A1) having an unsaturated aliphatic hydrocarbon group to the total of both may be 60% by mass or more, or may be 80% by mass or more, It may be 90% by mass or more. Moreover, the upper limit of the mass ratio is not particularly limited, and may be 98% by mass or less. Examples of (A) phenolic resins of such an aspect include phenolic resins having a structural unit derived from cardanol.

As the hydrocarbon group a1 which is a saturated aliphatic hydrocarbon group, various decyl groups ("various" means linear or branched, the same shall apply hereinafter), various undecyl groups (e.g., 4-pentylcyclohexyl group, etc.), various dodecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various octadecyl groups, and various eicosyl groups.
Examples of the hydrocarbon group a1, which is an unsaturated aliphatic hydrocarbon group, include those in which at least a portion of the saturated aliphatic hydrocarbon group having 10 to 25 carbon atoms is a carbon-carbon unsaturated bond. For example, 15 carbon atoms include 8-pentadecen-1-yl group, 8,11-pentadecadien-1-yl group, 8,11,14-pentadecatrien-1-yl group and the like.

From the viewpoint of low elasticity, the chain site of the hydrocarbon group a2 is preferably straight chain with 4 or more carbon atoms, more preferably straight chain with 5 or more carbon atoms. There is no particular limitation on the combination of chain and cyclic, and may be -chain-cyclic, -cyclic-chain, or -chain-cyclic-chain. Good, but preferably -cyclic-chain. -Cyclic-chain specific examples include 4-pentylcyclohexyl group (C11), 4-octylcyclohexyl group (C14), 4-decylcyclohexyl group (C16), 4-pentylcyclooctyl group (C13), 4- An octylcyclooctyl group (C16) and the like can be mentioned. Among these, a 4-pentylcyclohexyl group (C11) is preferable as -cyclic-chain.

The hydrocarbon group a1 and the hydrocarbon group a2 are preferably substituted at the meta-position (3-position or 5-position) with respect to the bonding position (1-position) of the hydroxy group of the phenol moiety.

（上記一般式中、Ｒ^１は、水素原子、置換基を有していてもよい炭素数１～９の脂肪族炭化水素基、置換基を有していてもよい環形成原子数５～１５の芳香族炭化水素基、又は、前記脂肪族炭化水素基と前記芳香族炭化水素基との組み合わせを示し、Ｒ^２は、炭素数１０～２５の脂肪族炭化水素基を示す。なお、（Ａ１）成分の場合においては、Ｒ^２は、炭素数１０～２５の鎖状脂肪族炭化水素基であり、（Ａ２）成分の場合においては、Ｒ^２は、鎖状脂肪族炭化水素基と環状脂肪族炭化水素基との組み合わせである炭素数が１０～２５の脂肪族炭化水素基である。Ｘは、水素原子、ヒドロキシ基又はヒドロキシメチル基である。ｍ及びｎは、それぞれ独立に、０又は１である。） As components (A1) and (A2), from the viewpoint of low elasticity and low hygroscopicity, a structural unit (a1) represented by the following general formula (a1) and a structural unit represented by the following general formula (a2) It preferably has at least one structural unit selected from the group consisting of (a2). In addition, it can be said that the (A1) component and the (A2) component have at least one structural unit (a2).

(In the above general formula, R ¹ is a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 9 carbon atoms, an optionally substituted ring-forming atom number of 5 to 15 or a combination of the aliphatic hydrocarbon group and the aromatic hydrocarbon group, and R ² represents an aliphatic hydrocarbon group having 10 to 25 carbon atoms. ) component, R ² is a chain aliphatic hydrocarbon group having 10 to 25 carbon atoms, and in the case of component (A2), R ² is a chain aliphatic hydrocarbon group and a cycloaliphatic is an aliphatic hydrocarbon group having 10 to 25 carbon atoms combined with a group hydrocarbon group, X is a hydrogen atom, a hydroxy group or a hydroxymethyl group, m and n are each independently 0 or 1.)

In the general formulas (a1) and (a2), "-*" represents a bond. At least one of the three bonds in general formula (a1) bonds to another structural unit, and at least one of the three bonds in general formula (a2) bonds to another structural unit. Of the bonds in each formula, those that do not bond to bonds of other structural units bond to hydrogen atoms.
However, the benzene ring in the structural unit (a1) and the benzene ring in the structural unit (a2) are bonded through a methylene group and are not directly bonded. Further, when the same molecule has two or more structural units (a1) and the structural units (a1) are bonded to each other, the benzene rings in each structural unit (a1) are bonded via a methylene group, Do not connect directly. Similarly, when the same molecule has two or more structural units (a2) and the structural units (a2) are bonded to each other, the benzene rings in each structural unit (a2) are bonded via a methylene group. , do not combine directly.

That is, the bond extending from the benzene ring in general formula (a1) bonds to another structural unit or bonds to a hydrogen atom. When bonding to another structural unit, the bond is bonded to a methylene group of the other structural unit (another structural unit (a1), or a structural unit (a2) in which at least one of m and n is 1) do.
A bond extending from a methylene group in general formula (a1) bonds to a benzene ring of another structural unit (structural unit (a2) or another structural unit (a1)).

A bond extending from the benzene ring in general formula (a2) bonds to another structural unit or bonds to a hydrogen atom. When bonding to another structural unit, the bond is bonded to the methylene group of the other structural unit (structural unit (a1), or another structural unit (a2) in which at least one of m and n is 1) do.
When m in the general formula (a2) is 0 (or n is 0), -(CH ₂ ) _m -* (or -(CH ₂ ) _n -*) is the same as the bond extending from the benzene ring indicates a bond (-*). That is, it binds to other structural units or binds to a hydrogen atom. When bonding to another structural unit, the bond bonds to a methylene group of the other structural unit in the same manner as the bond extending from the benzene ring.
When m in the general formula (a2) is 1 (or n is 1), -(CH ₂ ) _m -* (or -(CH ₂ ) _n -*) is a methylene group, and its bond is Binds to the benzene ring of another structural unit (structural unit (a1) or another structural unit (a2)).

（上記一般式（ａ１－１）及び（ａ１－２）中、Ｒ^１は前記一般式（ａ１）中のＲ^１と同じである。）
なお、一般式（ａ１－１）及び（ａ１－２）中の＊は、一般式（ａ１）中の＊の前記説明と同様に説明される。
本明細書において、構造単位（ａ１）に関する記載は、構造単位（ａ１－１）又は構造単位（ａ１－２）に読み替えることができる。 In the general formula (a1), the bonding position of R ¹ in the benzene ring is ortho to the bonding position (1 position) of the hydroxy group from the viewpoint of being inexpensive and the viewpoint that the synthesized resin is easily liquefied. The position (2-position or 6-position) is preferred, and in this case, general formula (a1) is represented by the following general formula (a1-1) or (a1-2), respectively.

(In general formulas (a1-1) and (a1-2) above, R ¹ is the same as R ¹ in general formula (a1) above.)
Note that * in general formulas (a1-1) and (a1-2) is explained in the same manner as the above explanation for * in general formula (a1).
In this specification, the description regarding the structural unit (a1) can be read as the structural unit (a1-1) or the structural unit (a1-2).

In general formula (a1), the bonding positions of the single bond and the methylene group in the benzene ring are not particularly limited. Typically, it is either ortho-position (2-position or 6-position) or para-position (4-position) with respect to the position (1-position) to which the hydroxy group is attached.

In the above formula, the aliphatic hydrocarbon group represented by R ¹ may be chain (straight-chain, branched), cyclic, or a combination of chain and cyclic. is preferred, and linear is more preferred.
The aliphatic hydrocarbon group may be either a saturated aliphatic hydrocarbon group having 1 to 9 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 9 carbon atoms. The saturated aliphatic hydrocarbon group having 1 to 9 carbon atoms is preferably a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, more preferably a saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms, still more preferably carbon It is a saturated aliphatic hydrocarbon group of number 1-3. The unsaturated aliphatic hydrocarbon group having 2 to 9 carbon atoms is preferably an unsaturated aliphatic hydrocarbon group having 2 to 6 carbon atoms, more preferably an unsaturated aliphatic hydrocarbon group having 2 to 4 carbon atoms. , more preferably an unsaturated aliphatic hydrocarbon group having 3 carbon atoms, particularly preferably an allyl group.
The aliphatic hydrocarbon group represented by R ¹ may have a substituent, and examples of the substituent include a hydroxy group, a halogen atom, an oxygen-containing hydrocarbon group, and a nitrogen-containing cyclic group. Examples of the halogen atom include fluorine atom, chlorine atom, bromine atom, and iodine atom. Examples of the oxygen-containing hydrocarbon group include ether bond-containing hydrocarbon groups. Examples of the nitrogen-containing cyclic group include a pyridyl group, a pyrimidinyl group, a quinolinyl group, an imidazolyl group and the like.

The aromatic hydrocarbon group represented by R ¹ may be a heteroatom-free aromatic hydrocarbon group (aryl group) or a heteroatom-containing heteroaromatic hydrocarbon group (heteroaryl group). may be used, but aromatic hydrocarbon groups (aryl groups) containing no heteroatoms are preferred. The aromatic hydrocarbon group has 5 to 15 ring-forming atoms. atoms, etc.), and does not include the number of atoms substituting on the aromatic ring (for example, hydrogen atoms, etc.).
The aromatic hydrocarbon group is preferably an aromatic hydrocarbon group having 5 to 12 ring atoms, more preferably an aromatic hydrocarbon group having 6 to 12 ring atoms, still more preferably a ring It is an aromatic hydrocarbon group having 6 to 10 forming atoms.
The aromatic hydrocarbon group may have a substituent, and examples of the substituent include an aliphatic hydrocarbon group having 1 to 5 carbon atoms, a hydroxy group and a halogen atom. Examples of the halogen atom include fluorine atom, chlorine atom, bromine atom, and iodine atom.

Combinations of the aliphatic hydrocarbon group and the aromatic hydrocarbon group represented by R ¹ include - aliphatic hydrocarbon group - aromatic hydrocarbon group, - aromatic hydrocarbon group - aliphatic hydrocarbon group, - Aliphatic hydrocarbon group-aromatic hydrocarbon group-aliphatic hydrocarbon group and the like can be mentioned. Among these, an -aliphatic hydrocarbon group-aromatic hydrocarbon group, the so-called aralkyl group, is preferred. The aromatic hydrocarbon group and the aliphatic hydrocarbon group are explained in the same manner as the aliphatic hydrocarbon group and the aromatic hydrocarbon group represented by R ¹ described above.

X is a hydrogen atom, a hydroxy group or a hydroxymethyl group, preferably a hydrogen atom or a hydroxymethyl group.

（上記一般式（ａ２－１）及び（ａ２－２）中、Ｘ及びＲ^２は、前記一般式（ａ２）中のＸ及びＲ^２と同じである。）
なお、一般式（ａ２－１）及び（ａ２－２）中の＊は、一般式（ａ２）中の＊の前記説明と同様に説明される。
本明細書において、構造単位（ａ２）に関する記載は、構造単位（ａ２－１）又は構造単位（ａ２－２）に読み替えることができる。 The aliphatic hydrocarbon group having 10 to 25 carbon atoms represented by R ² is explained in the same manner as the above-described hydrocarbon group a1 and hydrocarbon group a2. The R ² is preferably substituted at the meta-position (3-position or 5-position) with respect to the position (1-position) where the hydroxy group of the phenol moiety is bonded. 1) or (a2-2).

(In general formulas (a2-1) and (a2-2) above, X and R ² are the same as X and R ² in general formula (a2) above.)
Note that * in general formulas (a2-1) and (a2-2) is explained in the same manner as the above explanation for * in general formula (a2).
In this specification, the description of the structural unit (a2) can be read as the structural unit (a2-1) or the structural unit (a2-2).

When the (A1) component and the (A2) component have the structural unit (a1) and the structural unit (a2), the structural unit (a1) and the structural unit (a2) may each be one type, Two or more types may be used.
The molar ratio of the structural unit (a1) to the structural unit (a2) in the components (A1) and (A2) (structural unit (a1)/structural unit (a2)) is the (B) thermosetting From the viewpoints of reactivity with resins and low elasticity and low hygroscopicity, it is preferably 0 to 5.0, more preferably 0.25 to 5.0, even more preferably 1.0 to 3.0, particularly preferably 1.0 to 2.0.

The weight-average molecular weight (Mw) of component (A1) and component (A2) is preferably 4,000 or less, more preferably 1,000 to 3,000, and still more preferably 1,200 to 2, from the viewpoint of compatibility. , 000. When the weight average molecular weight is 1,000 or more, the reactivity with the thermosetting resin (B) is excellent, the heat resistance is not impaired, and the melt viscosity tends to be maintained.
As used herein, the weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) analysis using tetrahydrofuran (THF) as a dissolving solution, and is a value converted to standard polystyrene. The weight average molecular weight (Mw) is measured in more detail according to the method described in the Examples.
The hydroxyl equivalents of the components (A1) and (A2) are preferably 100 to 350 g/eq, more preferably 150 to 300 g/eq, and even more preferably 200 to 200 g/eq, from the viewpoint of improving the glass transition temperature and improving the insulating properties. 250 g/eq. A hydroxyl equivalent is measured according to the method described in the Examples.

(Method for producing component (A1) and component (A2))
There are no particular restrictions on the methods for producing the components (A1) and (A2), and known methods for producing phenolic resins can be employed. For example, the method for producing a polyhydric hydroxy resin described in JP-A-2015-89940 can be referred to and applied.
As one embodiment of a preferred production method, for example, a phenolic compound represented by the following general formula (2) and formaldehyde are reacted in the presence of a basic catalyst, and the resulting product and the following general formula (1) A method of reacting a phenolic compound represented by preferably in the presence of an acidic catalyst. A phenolic compound represented by the following general formula (1) forms the structural unit (a1), and a phenolic compound represented by the following general formula (2) forms the structural unit (a2). That is, the (A1) component and the (A2) component preferably contain a structural unit derived from the following general formula (1) and a structural unit derived from the following general formula (2).

（上記一般式（１）中のＲ^１は、前記一般式（ａ１）中のＲ^１と同じであり、上記一般式（２）中のＲ^２及びＸは、前記一般式（ａ２）中のＲ^２及びＸと同じである。）

(R ^{1 in the general formula (1) is the same as R 1 in} the general formula (a1), and R ² and X in the general formula (2) are Same as R ² and X.)

The content of component (A1) in the thermosetting resin composition of the present embodiment is not particularly limited, but is preferably 0.1 to 40 parts by mass, more preferably 1 to 20 parts by mass, more preferably 2 to 10 parts by mass, and particularly preferably 3 to 5 parts by mass. When the content of the component (A1) is at least the above lower limit value, it becomes easier to obtain low elasticity and high elongation, and when it is at most the above upper limit value, the glass transition temperature is further lowered and the flame retardancy is further lowered. And it tends to be able to suppress the increase in tackiness.
In the present specification, the "total amount of resin components" means the total amount of other components that do not contain inorganic compounds such as (E) fillers described later and organic solvents that can be contained as necessary, A) component, (B) component, (C) component, (D) component contained as necessary, etc. are included.

The content of component (A2) in the thermosetting resin composition of the present embodiment is not particularly limited, but is preferably 0.1 to 40 parts by mass, more preferably 1 to 30 parts by mass, more preferably 5 to 20 parts by mass, particularly preferably 10 to 15 parts by mass. When the content of the component (A2) is at least the above lower limit, it becomes easier to obtain even lower elasticity and high elongation, and when it is at most the above upper limit, the glass transition temperature is further lowered and the flame retardancy is further lowered. And it tends to be able to suppress the increase in tackiness.

The content ratio of the (A1) component and the (A2) component [(A1) component/(A2) component] in the thermosetting resin composition of the present embodiment is preferably 0.1 to 1 on a mass basis. , more preferably 0.15 to 0.6, still more preferably 0.2 to 0.4.

(A) The total amount of components (A1) and (A2) in the phenolic resin is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 100% by mass. is.

[(B) Thermosetting resin]
As the thermosetting resin (B), known thermosetting resins can be used, and there is no particular limitation. Examples include epoxy resins, cyanate resins, bismaleimide compounds, and addition polymerization of bismaleimide compounds and diamines. It is preferably one or more selected from the group consisting of polyolefins, isocyanate resins, triallyl isocyanurate resins, triallyl cyanurate resins and vinyl group-containing polyolefins. Among these resins, epoxy resins and cyanate resins are preferred, and epoxy resins are more preferred, from the viewpoint of a balance of properties such as heat resistance and insulation properties.
(B) component may be used individually by 1 type, and may use 2 or more types together.
In addition, in this embodiment, (A) component shall not be included in the definition of (B) thermosetting resin.

Although the epoxy resin is not particularly limited, an epoxy resin having two or more epoxy groups in one molecule is preferable from the viewpoint of improving heat resistance and glass transition temperature.
Epoxy resins are classified into glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, etc. Among these, glycidyl ether type epoxy resins are preferred.
Epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, phosphorus-containing epoxy resin, resins, naphthalene skeleton-containing epoxy resins, aralkylene skeleton-containing epoxy resins, phenol biphenyl aralkyl-type epoxy resins, phenol salicylaldehyde novolak-type epoxy resins, lower alkyl group-substituted phenol salicylaldehyde novolak-type epoxy resins, dicyclopentadiene skeleton-containing epoxy resins, At least one selected from the group consisting of functional glycidylamine type epoxy resins, polyfunctional alicyclic epoxy resins and tetrabromobisphenol A type epoxy resins is preferred.

From the viewpoint of compatibility, the epoxy equivalent of the epoxy resin is preferably 200-600 g/eq, more preferably 300-500 g/eq, and still more preferably 350-450 g/eq. The epoxy equivalent is the mass (g/eq) of resin per epoxy group, and can be measured according to the method specified in JIS K7236.

Examples of cyanate resins include novolac type cyanate resins, bisphenol A type cyanate resins, bisphenol E type cyanate resins, bisphenol F type cyanate resins, tetramethylbisphenol F type cyanate resins, and dicyclopentadiene type cyanate resins.

The content of the (B) thermosetting resin in the thermosetting resin composition of the present embodiment is not particularly limited, but is preferably 40 to 90 parts by mass, more preferably 50 to 85 parts by mass, more preferably 60 to 80 parts by mass.
The number of phenolic hydroxyl groups in component (A) relative to functional groups (eg, epoxy groups) in component (B) is not particularly limited, but is preferably 0.5 to 1.5 equivalents.
When the content of the component (B) is within the above range, the adhesion strength to the metal foil tends to be maintained, and the glass transition temperature and insulating properties tend to be suppressed from lowering.

[(C) acrylic polymer]
(C) The acrylic polymer is not particularly limited as long as it is obtained by polymerizing a monomer having a (meth)acryloyl group. It is preferable to include a structural unit (c2) represented by formula (c2), a structural unit (c3) represented by general formula (c3) below, and a structural unit (c4) represented by general formula (c4) below. .

（Ｒ^ｃ１は水素原子又はメチル基を示し、Ｒ^ｃ２は炭素数１～３の炭化水素基を示す。）

(R ^c1 represents a hydrogen atom or a methyl group, and R ^c2 represents a hydrocarbon group having 1 to 3 carbon atoms.)

（Ｒ^ｃ３は水素原子又はメチル基を示し、Ｒ^ｃ４は脂環式炭化水素基を含む炭素数５～２２の炭化水素基を示す。）

(R ^c3 represents a hydrogen atom or a methyl group, and R ^c4 represents a hydrocarbon group having 5 to 22 carbon atoms including an alicyclic hydrocarbon group.)

（Ｒ^ｃ５は水素原子又はメチル基を示し、Ｒ^ｃ６は炭素数４～１０の鎖状炭化水素基を示す。）

(R ^c5 represents a hydrogen atom or a methyl group, and R ^c6 represents a chain hydrocarbon group having 4 to 10 carbon atoms.)

（Ｒ^ｃ７は水素原子又は炭素数１～３のアルキル基を示し、Ｚは、ヒドロキシ基、又は、カルボキシ基、ヒドロキシ基、酸無水物基、アミノ基、アミド基及びエポキシ基からなる群から選択される１種以上の官能基を含む置換基を示す。）

(R ^c7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Z is selected from the group consisting of a hydroxy group, a carboxy group, a hydroxy group, an acid anhydride group, an amino group, an amide group and an epoxy group. indicates a substituent containing one or more functional groups that are

(Structural unit represented by general formula (c1))
Examples of the hydrocarbon group having 1 to 3 carbon atoms represented by R ^c2 in the general formula (c1) include a methyl group, an ethyl group and a propyl group.
Including the structural unit (c1) in the component (C) makes the component (C) excellent in heat resistance. When the component (C) contains a plurality of structural units (c1), the plurality of structural units (c1) may be the same or different.

Structural unit (c1) is a (meth)acrylic acid ester having a hydrocarbon group with 1 to 3 carbon atoms (hereinafter referred to as "mono (also referred to as "mer (c1)") can be obtained as a structural unit derived from the monomer.
Examples of the monomer (c1) include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. These may be used individually by 1 type, and may use 2 or more types together.
From the viewpoint of hygroscopicity, the monomer (c1) is preferably a methacrylic acid ester, more preferably methyl methacrylate.

(Structural unit represented by general formula (c2))
The number of carbon atoms in the hydrocarbon group including the alicyclic hydrocarbon group represented by R ^c4 in the general formula (c2) is 5-22, preferably 6-15, more preferably 7-10. When the number of carbon atoms is at least the above lower limit, the chemical stability of the monomer is sufficient, and the effect of reducing the moisture absorption rate of the component (C) is sufficient. The glass transition temperature becomes sufficient.
Examples of the alicyclic hydrocarbon group include cyclohexyl group, norbornyl group, tricyclodecanyl group, isobornyl group, and adamantyl group. By including the structural unit (c2) in the component (C), the moisture absorption rate can be efficiently reduced, and excellent electrolytic corrosion resistance can be obtained.
When the component (C) contains a plurality of structural units (c2), the plurality of structural units (c2) may be the same or different.

Structural unit (c2) is a (meth) acrylic having a hydrocarbon group having 5 to 22 carbon atoms including a cyclic hydrocarbon group as one of the monomer components used in the polymerization to obtain component (C). By using an acid ester (hereinafter also referred to as "monomer (c2)"), it is obtained as a structural unit derived from the monomer.
Examples of the monomer (c2) include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, norbornyl (meth)acrylate, and (meth)acrylic norbornylmethyl acid, phenylnorbornyl (meth)acrylate, cyanonorbornyl (meth)acrylate, isobornyl (meth)acrylate, bornyl (meth)acrylate, menthyl (meth)acrylate, (meth)acrylate fenchyl acrylate, adamantyl (meth)acrylate, dimethyladamantyl (meth)acrylate, tricyclo[5.2.1.0 ^2,6 ]dec-8-yl (meth)acrylate, tricyclo(meth)acrylate [ 5.2.1.0 ^2,6 ]deca-4-methyl, cyclodecyl (meth)acrylate and the like. These may be used individually by 1 type, and may use 2 or more types together.
Among these, from the viewpoint of low hygroscopicity and adhesion to metal foil, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, norbornyl methyl (meth) acrylate, ( meth)tricyclo[5.2.1.0 ^2,6 ]dec-8-yl acrylate, tricyclo[5.2.1.0 ^2,6 ]deca-4-methyl (meth)acrylate, (meth)acrylate Adamantyl acrylate is preferred, and tricycloacrylate [5.2.1. O ^2,6 ]dec-8-yl is more preferred.

(Structural unit represented by general formula (c3))
The chain hydrocarbon group represented by R ^c6 in the general formula (c3) has 4 to 10 carbon atoms, preferably 4 to 9 carbon atoms, and more preferably 4 to 8 carbon atoms. If the number of carbon atoms in the hydrocarbon group is at least the above lower limit, the elastomer will have good flexibility, and if it is at most the above upper limit, the electrical insulation will be sufficient.
The hydrocarbon group represented by R ^c6 may be either linear or branched, but from the viewpoint of resistance to mass reduction due to thermal decomposition and excellent heat resistance, a linear chain having 4 to 10 carbon atoms A branched hydrocarbon group having no tertiary carbon is preferred.
The hydrocarbon group represented by R ^c6 is preferably an aliphatic hydrocarbon group, more preferably an alkyl group. Examples of alkyl groups include butyl, pentyl, hexyl, octyl, 2-ethylhexyl, and decyl.
When the component (C) contains a plurality of structural units (c3), the plurality of structural units (c3) may be the same or different.

Structural unit (c3) uses a (meth)acrylic acid ester having a hydrocarbon group with 4 to 10 carbon atoms in the ester portion as one of the monomer components used in the polymerization to obtain component (C). By doing so, a structural unit derived from the monomer (hereinafter also referred to as "monomer (c3)") can be obtained.
Examples of the monomer (c3) include n-butyl (meth)acrylate, i-butyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, and n-(meth)acrylate. Hexyl, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate and the like can be mentioned. These may be used individually by 1 type, and may use 2 or more types together. Among these, 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate are preferred, and n-butyl acrylate and methacrylic acid 2 are preferred from the viewpoint of the glass transition temperature and SP value of the obtained component (C). - Ethylhexyl is more preferred.

(Structural unit represented by general formula (c4))
Z in the general formula (c4) contains a hydroxy group or one or more functional groups selected from the group consisting of a carboxy group, a hydroxy group, an acid anhydride group, an amino group, an amide group and an epoxy group. Indicates substituents.
When the component (C) contains a plurality of structural units (c4), the plurality of structural units (c4) may be the same or different.

Structural unit (c4) is obtained by using a (meth)acrylic acid ester having a substituent Z in the ester moiety as one of the monomer components used in the polymerization to obtain component (C). It is obtained as a structural unit derived from a monomer (hereinafter also referred to as "monomer (c4)").

Examples of the monomer (c4) having a "hydroxy group" as the substituent Z include unsaturated carboxylic acid monomers such as acrylic acid and methacrylic acid.

Examples of the monomer (c4) having a "substituent containing a carboxy group" as the substituent Z include 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl phthalate, 2-(meth) ) carboxy group-containing monomers such as acryloyloxyethylhexahydrophthalic acid and 2-(meth)acryloyloxypropylhexahydrophthalic acid.

Examples of the monomer (c4) having a "substituent containing a hydroxy group" as the substituent Z include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, cyclohexane di Examples include hydroxy group-containing monomers such as methanol mono(meth)acrylate and N-methylol(meth)acrylamide.

Examples of the monomer (c4) having a "substituent containing an acid anhydride group" as the substituent Z include (meth)acryloyloxyethyl trimellitic anhydride and (meth)acryloyloxyethyl cyclohexanetricarboxylic anhydride. acid anhydride group-containing monomers such as

Examples of the monomer (c4) having a "substituent containing an amino group" as the substituent Z include diethylaminoethyl (meth)acrylate and 2,2,6,6-tetramethylpiperidiate (meth)acrylate. Examples include amino group-containing monomers such as nyl and 1,2,2,6,6-pentamethylpiperidinyl (meth)acrylate.

Examples of the monomer (c4) having a "substituent containing an amide group" as the substituent Z include amide group-containing monomers such as N-(meth)acryloylglycinamide.

Examples of the monomer (c4) having a "substituent containing an epoxy group" as the substituent Z include glycidyl (meth)acrylate, 2-(2,3-epoxypropoxy)ethyl (meth)acrylate, 3-( 2,3-epoxypropoxy)propyl (meth)acrylate, 4-(2,3-epoxypropoxy)butyl (meth)acrylate, 5-(2,3-epoxypropoxy)pentyl (meth)acrylate, 6-(2, 3-epoxypropoxy)hexyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 4,5-epoxypentyl (meth)acrylate, 6,7-epoxyheptyl (meth)acrylate, 3-methyl-3,4-epoxybutyl (meth)acrylate, 4-methyl-4,5-epoxypentyl (meth)acrylate, 5-methyl-5,6-epoxyhexyl (meth)acrylate , β-methylglycidyl (meth)acrylate, 3-methyl-3,4-epoxybutyl (meth)acrylate, 4-methyl-4,5-epoxypentyl (meth)acrylate, (meth)acrylic Examples thereof include epoxy group-containing monomers such as acid-5-methyl-5,6-epoxyhexyl.

These monomers (c4) may be used individually by 1 type, and may use 2 or more types together.
Among these monomers (c4), from the viewpoint of storage stability, epoxy group-containing monomers are preferred, glycidyl (meth)acrylate is more preferred, and glycidyl methacrylate is even more preferred.

The content of each structural unit in component (C) is not particularly limited. The content of the unit (c3) is preferably 5 to 90% by mass, and the content of the structural unit (c4) is preferably 1 to 20% by mass.
The content of the structural unit (c1) in the component (C) is not particularly limited, but is preferably 10 to 50% by mass, still more preferably 15 to 40% by mass. When the content of the structural unit (c1) is at least the above lower limit value, the obtained component (C) has excellent glass transition temperature and SP value, and when it is at most the above upper limit value, a low elastic modulus is obtained.
The content of the structural unit (c2) in component (C) is not particularly limited, but is preferably 2 to 10% by mass, still more preferably 3 to 7% by mass. When the content of the structural unit (c2) is at least the above lower limit, the hygroscopicity and chemical resistance are excellent. It becomes a thing.
The content of the structural unit (c3) in the component (C) is not particularly limited, but from the viewpoint of electrolytic corrosion resistance and flexibility, it is more preferably 30 to 85% by mass, still more preferably 50 to 80% by mass. When the content of the structural unit (c3) is at least the above lower limit value, excellent electrolytic corrosion resistance is obtained, and when it is at most the above upper limit value, an excellent glass transition temperature is obtained.
The content of the structural unit (c4) in component (C) is not particularly limited, but is preferably 2 to 10% by mass, still more preferably 3 to 7% by mass. When the content of the structural unit (c4) is at least the above lower limit value, the adhesiveness and strength become more sufficient, and when it is at most the above upper limit value, the cross-linking reaction during copolymerization is suppressed and the storage stability is improved. become good.
The content of other structural units in component (C) is not particularly limited, but is preferably 25% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

(Method for producing component (C))
Component (C) is preferably obtained by polymerizing a monomer mixture containing monomer (c1), monomer (c2), monomer (c3) and monomer (c4). .
The monomer mixture may consist only of the monomer (c1), the monomer (c2), the monomer (c3) and the monomer (c4). It may contain other monomers copolymerizable with.
Other monomers include, for example, 4-vinylpyridine, 2-vinylpyridine, α-methylstyrene, α-ethylstyrene, α-fluorostyrene, α-chlorostyrene, α-bromostyrene, fluorostyrene, chlorostyrene , bromostyrene, methylstyrene, methoxystyrene, (o-, m-, p-) hydroxystyrene, aromatic vinyl compounds such as styrene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; unsaturated compounds such as maleic anhydride Dicarboxylic anhydrides; N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, Ni-propylmaleimide, N-butylmaleimide, Ni-butylmaleimide, Nt-butylmaleimide, N-lauryl N-substituted maleimides such as maleimide, N-cyclohexylmaleimide, N-benzylmaleimide and N-phenylmaleimide; and vinyl acetate.
Another monomer may be used individually by 1 type, and may use 2 or more types together.

The amount of each monomer used is preferably adjusted so that the content of each structural unit in the resulting component (C) is within the above range.

Existing methods such as bulk polymerization, suspension polymerization, solution polymerization, precipitation polymerization and emulsion polymerization can be applied as the polymerization method for producing component (C). Among these, suspension polymerization is preferred from the viewpoint of economy.
Suspension polymerization can be carried out, for example, in an aqueous medium containing a suspending agent. Suspending agents include water-soluble polymers such as polyvinyl alcohol, methylcellulose and polyacrylamide; sparingly soluble inorganic substances such as calcium phosphate and magnesium pyrophosphate. Among these, nonionic water-soluble polymers such as polyvinyl alcohol are preferred. A suspending agent may be used individually by 1 type, and may use 2 or more types together.
The amount of suspending agent used is, for example, 0.01 to 1 part by mass with respect to 100 parts by mass of the total amount of the monomers.

(C) It is preferable to use a radical polymerization initiator for the polymerization for producing the component. Radical polymerization initiators include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-t-butylperoxy-3. ,3,5-trimethylcyclohexane, organic peroxides such as t-butylperoxyisopropyl carbonate; azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile , azodibenzoyl and the like; water-soluble catalysts such as potassium persulfate and ammonium persulfate; and redox catalysts by combining peroxides or persulfates with reducing agents. The radical polymerization initiator may be used alone or in combination of two or more.
The amount of radical polymerization initiator to be used is, for example, 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of monomers.

A chain transfer agent may be used in the polymerization for producing the component (C) from the viewpoint of adjusting the molecular weight of the resulting component (C). Examples of chain transfer agents include mercaptan compounds, thioglycol, carbon tetrachloride, α-methylstyrene dimer, and the like. A chain transfer agent may be used individually by 1 type, and may use 2 or more types together.

The polymerization temperature is not particularly limited, but is, for example, in the range of 0 to 200°C, preferably 40 to 120°C from the viewpoint of reaction rate and productivity.

(Physical properties of component (C))
The weight average molecular weight of component (C) is not particularly limited, but is preferably 100,000 to 1,000,000, more preferably 200,000 to 900,000, and still more preferably 300,000 to 800,000. . When the weight average molecular weight is at least the above lower limit, it has a sufficiently low elastic modulus and high adhesive strength with the metal foil is obtained. become good.

The solubility parameter (SP value) of component (C) is not particularly limited, but is preferably 10.0 to 12.0, more preferably 10.1 to 11.0, still more preferably 10.2 to 10.5. be. When the SP value is at least the above lower limit, the heat resistance tends to improve, and when it is at most the above upper limit, the insulation reliability tends to improve.
The SP value of component (C) can be calculated from the structure of the material by the Fedors method. From the structure of the material, the total molar cohesive energy and total molar molecular capacity are obtained by summing the number of members of the functional groups that are composed and the molar cohesive energy and molar molecular capacity of each functional group shown in the table below, It is calculated by the following formula (1).

式（１）中の記号はそれぞれ、δiはＳＰ値、ΔＥｉは合計モル凝集エネルギー、ΔＶｉは合計モル分子容量を示す。

The symbols in formula (1) respectively represent δi, SP value, ΔEi, total molar cohesive energy, and ΔVi, total molar molecular capacity.

Specifically, taking the case of methyl methacrylate as an example, when the SP value is calculated by the above method, the result is as follows. In this case, methyl methacrylate is
Structural formula: _CH3 -C(= _CH2 )-C(=O)-O- _CH3
Number of members: CH ₃ 2 pieces
1 _CH2
>C< 1 piece
> 1 CO
-O- 1 piece, from Table 1,
Total molar cohesive energy (ΔEi): (1125 x 2) + (1180 x 1) + (350 x 1) + (4150 x 1) + (800 x 1) = 8730
Total molar molecular capacity (ΔVi): (33.5 x 2) + (16.1 x 1) + (-19.2 x 1) + (10.8 x 1) + (3.8 x 1) = 78 .5
and applying this to equation (1),

and the solubility parameter (SP value) are calculated.
(C) The SP value of the acrylic polymer is calculated from the composition ratio of each monomer. Specifically, as an example of copolymerization at a weight ratio of methyl methacrylate/butyl acrylate=40, the SP value is calculated as follows. Since the SP value of methyl methacrylate is 10.55 and the SP value of butyl acrylate is 10.21, it is calculated as 10.55×0.4+10.21×0.6=10.35.

The content of component (C) in the thermosetting resin composition of the present embodiment is not particularly limited, but is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, with respect to 100 parts by mass of the total amount of resin components. parts by mass, more preferably 15 to 30 parts by mass. When the content of component (C) is at least the above lower limit, there is a tendency for excellent low elasticity, flexibility and high elongation, and sufficient adhesion strength to the metal foil can be obtained. , sufficient heat resistance can be obtained.

[(D) Curing accelerator]
The thermosetting resin composition of the present embodiment preferably further contains (D) a curing accelerator. The curing accelerator (D) can be appropriately selected depending on the type of the thermosetting resin (B), and may be used alone or in combination of two or more.
For example, when an epoxy resin is used as the component (B), the curing accelerator (D) is not particularly limited, but is preferably an amine compound or an imidazole compound, more preferably an imidazole compound.
Examples of amine compounds include dicyandiamide, diaminodiphenylethane, guanylurea, and the like.
Examples of imidazole compounds include 2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate. , benzimidazole and the like. Among these, imidazole compounds are preferred, and 2-phenylimidazole is more preferred.
When the thermosetting resin composition of the present embodiment contains (D) curing accelerator, the content of (D) curing accelerator is not particularly limited, but the total amount of components (A) and (B) is 100 It is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and still more preferably 0.05 to 3 parts by mass.

[(E) Filler]
The thermosetting resin composition of the present embodiment preferably further contains (E) a filler.
(E) Filler may be used alone or in combination of two or more.
(E) The filler is not particularly limited, and known fillers can be used. The (E) filler may be an organic filler or an inorganic filler, but an inorganic filler is preferable from the viewpoint of low thermal expansion coefficient and flame retardancy.
Inorganic fillers include silica, alumina, titanium oxide, mica, beryllia, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, Calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay (calcined clay, etc.), talc, aluminum borate, silicon carbide, and the like. Among these, silica is preferable from the viewpoint of low dielectric constant and low coefficient of thermal expansion. Silica includes, for example, precipitated silica which is produced by a wet method and has a high water content, and dry-process silica which is produced by a dry method and contains almost no bound water. Examples include crushed silica, fumed silica, fused silica (fused spherical silica), and the like. Among these, fused silica (fused spherical silica) and pulverized silica are preferred.

The average particle size of the (E) filler is not particularly limited, but is preferably 0.1 to 10 μm, more preferably 0.3 to 4.0 μm. When the average particle diameter is 0.1 μm or more, the dispersibility of the fillers becomes good, and the viscosity of the varnish is lowered, so that the handleability tends to be good. Further, when the average particle size is 10 μm or less, the (E) filler tends to be less likely to sediment during varnish formation. Here, the average particle size is the particle size at the point corresponding to 50% volume when the cumulative frequency distribution curve by particle size is obtained with the total volume of the particles being 100%, and the laser diffraction scattering method is used. It can be measured with a particle size distribution measuring device or the like.

(E) The filler may be surface-treated with a coupling agent from the viewpoint of improving the dispersibility and the adhesion of the prepreg to the substrate and the metal foil.
The coupling agent is preferably a silane coupling agent, and examples of the silane coupling agent include epoxysilane coupling agents, aminosilane coupling agents, vinylsilane coupling agents, and phenylsilane coupling agents. . Among these, aminosilane coupling agents are preferred. A coupling agent may be used individually by 1 type, and may use 2 or more types together.
In the case of using a coupling agent, a so-called integral blend processing method in which the coupling agent is added after the filler (E) is blended into the thermosetting resin composition may be used. is preferably dry or wet surface-treated (E).

When the thermosetting resin composition of the present embodiment contains (E) a filler, the content of the (E) filler is not particularly limited, but is preferably 10 to 150 parts by mass with respect to 100 parts by mass of the total resin component. parts, more preferably 20 to 100 parts by mass, still more preferably 30 to 70 parts by mass. When the content of the (E) filler is at least the above lower limit value, low thermal expansion, heat resistance and low tackiness are excellent, and when it is at most the above upper limit value, there is a tendency to sufficiently obtain a low elasticity effect.

[Other ingredients]
The thermosetting resin composition of the present embodiment comprises, if necessary, a curing agent for the component (B) (excluding the component (A)); a cross-linking agent such as isocyanate and melamine; a rubber elastomer; Flame retardants such as phosphorus compounds; conductive particles; coupling agents; flow control agents; antioxidants; pigments; leveling agents;

〔Organic solvent〕
The thermosetting resin composition of the present embodiment may be a varnish-like thermosetting resin composition containing an organic solvent from the viewpoint of facilitating the production of a prepreg to be described later. The organic solvent may contain the organic solvent used in the production of the components (A) and (B), etc., or may be a new compound.
Examples of organic solvents include, but are not limited to, ketone solvents, aromatic hydrocarbon solvents, ester solvents, amide solvents, alcohol solvents, and the like. Among these, ketone solvents are preferred from the viewpoint of solubility. Ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like. An organic solvent may be used individually by 1 type, and may use 2 or more types together.
The varnish preferably has a non-volatile content of 25 to 65% by mass from the viewpoints of handleability, impregnation of the prepreg into the base material, and appearance of the prepreg. In this specification, the term "non-volatile matter" refers to a component that remains when the organic solvent contained in the thermosetting resin composition is removed, and includes the above (E) filler.

(storage modulus)
The storage elastic modulus of the cured product (laminate) obtained from the thermosetting resin composition of the present embodiment is not particularly limited, but from the viewpoint of expressing the stress relaxation effect, it is preferably 4.0 GPa or less, more preferably 3 0.7 GPa or less, more preferably 3.2 GPa or less, particularly preferably 2.7 GPa or less. The lower limit of the storage modulus is not particularly limited, and may be 1.0 GPa or more. The storage modulus can be measured by the method described in Examples.

(Tensile elongation)
The tensile elongation at 25° C. of the cured product (laminate) obtained from the thermosetting resin composition of the present embodiment is not particularly limited, but is preferably 2.5% or more from the viewpoint of expressing the stress relaxation effect. , more preferably 2.8% or more, still more preferably 3.0% or more, and particularly preferably 3.1% or more. Although the upper limit of the tensile elongation at 25°C is not particularly limited, it may be 6.0% or less.
The tensile elongation at 125° C. is not particularly limited, but from the viewpoint of exhibiting a stress relaxation effect in a high temperature environment and resilience to thermal expansion when temperature changes occur between normal temperature environment and high temperature environment. , preferably 6.0% or more, more preferably 8.0% or more, still more preferably 9.0% or more, even more preferably 9.5% or more, particularly preferably 9.7% or more, most preferably 9 .8% or more. Although the upper limit of the tensile elongation at 125°C is not particularly limited, it is usually 12.0% or less. The tensile elongation can be measured by the method described in Examples.

(Copper foil peel strength)
In the cured product obtained from the thermosetting resin composition of the present embodiment, the copper foil peel strength at 25° C. is not particularly limited, but is preferably 0.50 kN when measured according to the method described in Examples. /m or more, more preferably 0.80 kN/m or more, still more preferably 0.83 kN/m or more, and particularly preferably 0.85 kN/m or more. The upper limit of the copper foil peel strength at 25° C. is not particularly limited, but usually it may be 2.0 kN/m or less.
In addition, the copper foil peel strength at 125° C. is not particularly limited, but is preferably 0.40 kN/m or more, more preferably 0.50 kN/m or more, still more preferably 0.55 kN/m or more, and particularly preferably is greater than or equal to 0.57 kN/m, most preferably greater than or equal to 0.60 kN/m. The upper limit of the copper foil peel strength at 125° C. is not particularly limited, but may be 1.50 kN/m or less.

The cured product of the thermosetting resin composition of the present embodiment preferably does not form a phase-separated structure from the viewpoint of enhancing adhesion to the metal foil. By not forming a phase-separated structure, the elongation rate is improved in a room temperature environment and a high temperature environment, whereby the stress relaxation effect can be effectively exhibited, so that the adhesiveness to the metal foil can be enhanced. In addition, in this embodiment, the presence or absence of a phase separation structure can be confirmed by the method described in Examples.

[Prepreg]
The prepreg of this embodiment contains the thermosetting resin composition of this embodiment.
The prepreg of the present embodiment can be produced by impregnating a substrate with the thermosetting resin composition of the present embodiment and drying.
The base material is not particularly limited as long as it is a base material used in manufacturing metal-clad laminates or printed wiring boards, but fiber base materials such as woven fabrics and non-woven fabrics are usually used. Inorganic fibers such as glass, alumina, asbestos, boron, silica-alumina glass, silica glass, tyranno, silicon carbide, silicon nitride, zirconia; aramid, polyetheretherketone, polyetherimide, polyether organic fibers such as sulfone, carbon and cellulose; and fibers obtained by blending these. Among these, glass cloth is preferable. The thickness of the fiber base material is, for example, 160 μm or less, preferably 10 to 160 μm, more preferably 15 to 100 μm, still more preferably 20 to 50 μm.
The fiber base material is a glass cloth of 50 μm or less because it is possible to obtain a printed wiring board that can be bent arbitrarily, and it is possible to reduce dimensional changes due to temperature, moisture absorption, etc. in the manufacturing process. Preferably.

There are no particular restrictions on the conditions for producing the prepreg, but it is preferable to volatilize 80% by mass or more of the organic solvent contained in the varnish to obtain the prepreg. The drying temperature is preferably 80 to 180°C, more preferably 110 to 160°C.

[Metal foil with resin]
The resin-coated metal foil of this embodiment is obtained by laminating the thermosetting resin composition of this embodiment and a metal foil.
The resin-coated metal foil of the present embodiment can be produced, for example, by coating a metal foil with the thermosetting resin composition of the present embodiment made into a varnish, if necessary, and drying the composition.
The drying conditions are not particularly limited, but the drying temperature is preferably 80 to 180°C, more preferably 110 to 160°C.
The coating method is not particularly limited, and known coating machines such as a die coater, a comma coater, a bar coater, a kiss coater and a roll coater can be used.

[Laminate]
The laminate of the present embodiment contains the prepreg of the present embodiment or the resin-coated metal foil of the present embodiment.
The laminate of the present embodiment can be produced, for example, by laminating a plurality of prepregs of the present embodiment and heating and pressurizing them.
The laminate of the present embodiment may contain only the prepreg of the present embodiment as a prepreg, but a laminate made of a plurality of prepregs different from that of the present embodiment and a laminate of a plurality of prepregs of the present embodiment It may be a laminate with a laminate other than the above. The laminate composed of a plurality of prepregs different from that of the present embodiment includes, for example, a laminate having a higher storage elastic modulus than the laminate composed of a plurality of prepregs of the present embodiment. Since the laminate consisting of multiple prepreg sheets of the present embodiment provides a stress relaxation effect, by adopting this aspect, printed wiring that may occur when only a laminate consisting of a plurality of prepreg sheets different from that of the present embodiment is used. It is possible to suppress the occurrence of cracks in the plate.

The laminate of this embodiment may be a metal-clad laminate obtained by laminating the prepreg of this embodiment and metal foil.
The metal-clad laminate is, for example, laminated so that the adhesive surfaces on both sides of the laminate and the metal foil are aligned, and under vacuum press conditions, preferably 130 to 250 ° C., more preferably 150 to 230 ° C., and preferably can be produced by heat and pressure molding under conditions of 0.5 to 10 MPa, more preferably 1 to 5 MPa.
A metal-clad laminate can also be manufactured by preparing two metal foils with resin of this embodiment, stacking them so that their resin surfaces face each other, and pressing them under vacuum press conditions. The method of heating and pressurizing is not particularly limited, and a multistage press, multistage vacuum press, continuous molding, autoclave molding machine, or the like can be used.

The metal foil used for the resin-coated metal foil and the metal-clad laminate of the present embodiment is not particularly limited, and examples thereof include copper foil and aluminum foil.
The thickness of the metal foil is not particularly limited, but it is preferably selected from the range of 1 to 200 μm, which is the thickness of metal foil generally used for laminates, more preferably 10 to 100 μm, and still more preferably 10 to 50 μm. is.

[Printed wiring board]
The printed wiring board of this embodiment contains the laminate of this embodiment.
The printed wiring board of the present embodiment is, for example, obtained by subjecting the laminate of the present embodiment to circuit processing. (Metal-clad laminates) may be subjected to circuit (wiring) processing by a known method.

[Semiconductor package]
The semiconductor package of this embodiment contains the printed wiring board of this embodiment. The semiconductor package of this embodiment can be manufactured by mounting a semiconductor chip, a memory, etc. on a predetermined position of the printed wiring board of this embodiment by a known method.

Examples and comparative examples are shown below to specifically describe the present embodiment, but the present embodiment is not limited to these.
The weight average molecular weight and hydroxyl equivalent weight of the components used in each example were measured by the following methods.

[Weight average molecular weight]
The weight average molecular weight was converted from a calibration curve using standard polystyrene by a gel permeation chromatography (GPC) method. Calibration curve, standard polystyrene: TSK standard POLYSTYRENE (Type; A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, product name] and approximated by a cubic equation. GPC measurement conditions are shown below.
Device:
Pump: L-6200 type [manufactured by Hitachi High-Technologies Corporation]
Detector: L-3300 type RI [manufactured by Hitachi High-Technologies Corporation]
Column oven: L-655A-52 [manufactured by Hitachi High-Technologies Corporation]
Column: Guard column; TSK Guardcolumn HHR-L + column; TSKgel G4000HHR + TSKgel G2000HHR (all manufactured by Tosoh Corporation, trade name)
Column size: 6.0 mm x 40 mm (guard column), 7.8 mm x 300 mm (column)
Eluent: Tetrahydrofuran Sample concentration: 30 mg/5 mL
Injection volume: 20 μL
Flow rate: 1.00 mL/min Measurement temperature: 40°C

[Hydroxyl equivalent]
(A) The hydroxyl group equivalent (g/eq) of the phenolic resin was obtained by titration by the acetylation method with acetic anhydride using an automatic titrator "COM-1700S" (manufactured by Hiranuma Sangyo Co., Ltd.).

[(A) Synthesis of phenolic resin]
Synthesis example 1
((A1) component: synthesis of phenolic resin (A-1))
300 g (1.0 mol) of cardanol, 150 g of methanol, and 120 g (2.0 mol) of 50% formaldehyde aqueous solution were charged in a 2 L glass flask equipped with a thermometer, a stirrer and a condenser, and the mixture was added with 30% water. An aqueous sodium oxide solution was added dropwise over 2 hours. After that, the temperature was raised to 45° C. and the reaction was carried out for 6 hours. Next, 35% hydrochloric acid was added to the resulting reaction solution to neutralize the sodium hydroxide, then 1,342 g (10 mol) of o-allylphenol was added, and 1.34 g (10 mol) of oxalic acid was added to the o-allylphenol. 0.1% by mass relative to the total amount) was added to acidify the inside of the system, the temperature was raised to 100° C., and then the reaction was carried out for 5 hours. After that, the reaction solution was washed with water, and excess o-allylphenol was distilled off to obtain a phenolic resin (A-1).
The obtained phenolic resin (A-1) had a weight average molecular weight (Mw) of 1,412 and a hydroxyl equivalent of 214 g/eq.

Synthesis example 2
((A2) component: synthesis of phenolic resin (A-2))
248 g (1.0 mol) of p-(4-pentylcyclohexyl)phenol, 150 g of methanol, and 120 g (2.0 mol) of 50% formaldehyde aqueous solution were charged into a 2 L glass flask equipped with a thermometer, a stirrer and a condenser tube. , and a 30% sodium hydroxide aqueous solution was added dropwise to the mixture over 2 hours. After that, the temperature was raised to 45° C. and the reaction was carried out for 6 hours. Next, 35% hydrochloric acid was added to the resulting reaction solution to neutralize the sodium hydroxide, then 1,342 g (10 mol) of o-allylphenol was added, and 1.34 g (10 mol) of oxalic acid was added to the o-allylphenol. 0.1% by mass relative to the total amount) was added to acidify the inside of the system, the temperature was raised to 100° C., and then the reaction was carried out for 5 hours. Thereafter, the reaction solution was washed with water, and excess o-allylphenol was distilled off to obtain a phenolic resin (A-2).
The obtained phenolic resin (A-2) had a weight average molecular weight (Mw) of 1,738 and a hydroxyl equivalent of 238 g/eq.

[(C) Synthesis of acrylic polymer]
Synthesis example 3
(Synthesis of acrylic polymer (C-1))
5 g of lauroyl peroxide as a peroxide and n-octyl mercaptan as a chain transfer agent were added to a monomer mixture (1000 g in total) obtained by mixing at the monomer blending ratio (by mass) shown in Table 2. 0.45 g was dissolved to form a mixed solution.
Next, 0.3 g of polyvinyl alcohol as a suspending agent and 2000 g of ion-exchanged water were added to a 5 L autoclave equipped with a stirrer and a condenser, and the mixture was added while stirring. Polymerization was carried out in an atmosphere at 60° C. for 5 hours and then at 90° C. for 2 hours to obtain resin particles. The resin particles were washed with water, dehydrated and dried, and dissolved in methyl ethyl ketone so that the heating residue was 30% by mass to obtain a solution of acrylic polymer (C-1).

Synthesis Examples 4-7
(Synthesis of acrylic polymers (C-2) to (C-5))
Solutions of acrylic polymers (C-2) to (C-5) were obtained in the same manner as in Synthesis Example 3, except that the blending ratio of the monomers in Synthesis Example 3 was changed as shown in Table 2. rice field.

Examples 1-6, Comparative Examples 1-4
Each component other than the (D) component shown in Table 3 has a composition shown in Table 3 (the amount in the table is parts by mass, and in the case of a solution (excluding organic solvents) or dispersion, it is the solid content conversion amount ) and dissolved in methyl isobutyl ketone, component (D) was blended according to the blending composition shown in Table 3 to obtain a varnish having a non-volatile content of 40% by mass. In addition, the details of each component described in Table 3 are as follows.

[(A) Phenolic resin]
(A-1): Phenolic resin (A-1) obtained in Synthesis Example 1
(A-2): Phenolic resin (A-2) obtained in Synthesis Example 2

[(B) Thermosetting resin]
EPICLON 153: Tetrabromobisphenol A type epoxy resin (manufactured by DIC Corporation, trade name, epoxy equivalent 400 g/mol)

[(C) acrylic polymer]
(C-1) to (C-5): Acrylic polymers (C-1) to (C-5) obtained in Synthesis Examples 3 to 7

[(E) Filler]
・Megasil 525 ARI: fused silica treated with an aminosilane coupling agent (manufactured by Sibelco Japan Co., Ltd., trade name, average particle size: 1.9 μm, specific surface area: 5.8 m ² /g)
・ F05-12: crushed silica (manufactured by Fukushima Ceramics Co., Ltd., trade name, average particle size 2.5 μm)
・ SC-2050-KNK: Silica filler treated with an aminosilane coupling agent (manufactured by Admatechs Co., Ltd., trade name, average particle size 0.5 μm)

Using the varnish produced in each example, a prepreg, a resin-coated copper foil, and a copper-clad laminate were produced by the following methods, and each evaluation was performed by the methods described later.

[Production of prepreg]
A glass cloth 1037 (manufactured by Asahi Schwebel Co., Ltd., trade name) with a thickness of 0.028 mm was impregnated with the varnish prepared in each example, and then dried by heating at 140° C. for 10 minutes to obtain a prepreg.

[Production of resin-coated copper foil]
The varnish prepared in each example is applied to a 35 μm thick electrolytic copper foil “YGP-35” (manufactured by Nippon Denki Co., Ltd., trade name) with a coating machine, dried with hot air at 140 ° C. for about 6 minutes, A resin-coated copper foil having a coating thickness of 50 μm was produced.

[Preparation of copper-clad laminate]
Electrolytic copper foil "YGP-35" (manufactured by Nippon Denki Co., Ltd., trade name) with a thickness of 35 μm is superimposed on both sides of the four stacked prepregs so that the adhesive surfaces are aligned with the prepregs, and subjected to 4 MPa pressure at 200 ° C. for 60 minutes. A double-sided copper-clad laminate was produced under vacuum press conditions.
The resin-coated copper foils were stacked so that the resin surfaces faced each other, and a double-sided copper-clad laminate was produced under vacuum press conditions of 4 MPa at 200° C. for 60 minutes.

(1) Confirmation of Phase Separation Structure The phase separation structure was confirmed by smoothing the cross section of the resin insulation layer of the double-sided copper-clad laminate made from the resin-coated copper foil with a microtome, followed by etching with a persulfate solution. The obtained sample was observed by SEM (apparatus name: SU-3500, manufactured by Hitachi High-Technologies Corporation, acceleration voltage 10 KV). In addition, in the SEM observation, when a phase separation structure was confirmed at 3000 magnifications, the phase separation was "presence", and when the phase separation structure was not confirmed, the phase separation was "absence". Table 3 shows the results.

(2) Storage modulus Storage modulus was evaluated by cutting a laminate obtained by etching the entire copper foil of a double-sided copper-clad laminate made from a resin-coated copper foil into a width of 5 mm and a length of 30 mm. The storage elastic modulus was measured using a dynamic viscoelasticity measuring device (manufactured by UBM Co., Ltd.). It was determined that if the storage elastic modulus at 25° C. is 4.0 GPa or less, the elasticity is sufficiently low, the stress relaxation effect can be exhibited, and the occurrence of cracks in the printed wiring board can be suppressed. Table 3 shows the results.

(3) Heat resistance A test piece was obtained by cutting a double-sided copper-clad laminate made from a prepreg into a 50 mm square. The test piece was floated in a solder bath at 260° C., and the elapsed time from that point to the point at which swelling of the test piece was visually observed was measured and used as an index of heat resistance. The elapsed time was measured up to 1800 seconds, and when 1800 seconds or more elapsed, it was judged that the heat resistance was sufficient. Table 3 shows the results.

(4) Tensile elongation (25°C and 125°C)
A laminate obtained by etching the entire copper foil of a double-sided copper-clad laminate made from a resin-coated copper foil was cut into a width of 10 mm and a length of 100 mm, and a thermostat-equipped autograph (manufactured by Shimadzu Corporation). was used to measure the tensile elongation at 25°C and 125°C. It was determined that the stress relaxation effect can be exhibited when the tensile elongation at 25°C is 3.0% or more and the tensile elongation at 125°C is 5.0% or more. Table 3 shows the results.

(5) Copper foil peel strength (25°C and 125°C)
A copper foil line with a width of 3 mm was formed by partially etching the copper foil of the double-sided copper-clad laminate produced from the above four prepregs. Next, using a constant temperature bath type peel tester (manufactured by Shimadzu Corporation), the temperature is set at 25 ° C. or 125 ° C., and the copper foil line is moved at 90 ° to the adhesive surface at 50 mm / min. The load at the time of peeling off at a speed of was measured and used as an index of adhesion to the metal foil. If the copper foil peel strength at 25 ° C. is 0.80 kN / m or more and the copper foil peel strength at 125 ° C. is 0.40 kN / m or more, it is considered that the adhesion with the metal foil is sufficient. It was judged. Table 3 shows the results.

As is clear from Table 3, Examples 1 to 6 using the thermosetting resin composition of the present embodiment have sufficient heat resistance and low elastic modulus, and can withstand metal under normal temperature and high temperature environments. It can be seen that it has a high adhesive strength with the foil. On the other hand, Comparative Examples 1, 2 and 4, which did not contain the (A1) component, had low tensile elongation under high temperature environments. Furthermore, Comparative Examples 3 and 4, which do not contain the component (C), had a large storage elastic modulus.

Claims (15)

(A) a phenolic resin,
A thermosetting resin composition containing (B) a thermosetting resin and (C) an acrylic polymer,
The component (A) comprises (A1) a phenolic resin having a chain aliphatic hydrocarbon group having 10 to 25 carbon atoms , and (A2) a combination of a chain aliphatic hydrocarbon group and a cyclic aliphatic hydrocarbon group. and a phenolic resin having an aliphatic hydrocarbon group having 10 to 25 carbon atoms ,
The component (B) is an epoxy resin,
A thermosetting resin composition in which the component (C) contains 10 to 50% by mass of a structural unit (c1) represented by the following general formula (c1) .

(R ^c1 represents a hydrogen atom or a methyl group, and R ^c2 represents a hydrocarbon group having 1 to 3 carbon atoms.) The thermosetting resin composition according to claim 1, wherein the component (A1) contains a structural unit derived from the following general formula (1) and a structural unit derived from the following general formula (2).

(In the formula, R ¹ is a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 9 carbon atoms, an optionally substituted aromatic group having 5 to 15 ring atoms R ² represents a chain aliphatic hydrocarbon group having 10 to 25 carbon atoms, and X represents hydrogen. atom, hydroxy group or hydroxymethyl group.) The content of the (A1) component is 0.1 to 40 parts by mass with respect to 100 parts by mass of the total resin component of the thermosetting resin composition, The thermosetting resin composition according to claim 1 or 2. thing. The content of the component (A2) is 0.1 to 40 parts by mass with respect to 100 parts by mass of the total resin component of the thermosetting resin composition, according to any one of claims 1 to 3. A thermosetting resin composition. (C) The acrylic polymer further comprises a structural unit (c2) represented by the following general formula (c2), a structural unit (c3) represented by the following general formula (c3), and a structural unit (c4) represented by the following general formula (c4). The thermosetting resin composition according to any one of claims 1 to 4, which contains a structural unit (c4).

(R ^c3 represents a hydrogen atom or a methyl group, and R ^c4 represents a hydrocarbon group having 5 to 22 carbon atoms including an alicyclic hydrocarbon group.)

(R ^c5 represents a hydrogen atom or a methyl group, and R ^c6 represents a chain hydrocarbon group having 4 to 10 carbon atoms.)

(R ^c7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Z is selected from the group consisting of a hydroxy group, a carboxy group, a hydroxy group, an acid anhydride group, an amino group, an amide group and an epoxy group. indicates a substituent containing one or more functional groups that are The content of the structural unit (c1) in the component (C) is 1 to 60 mass%, the content of the structural unit (c2) is 1 to 20 mass%, and the content of the structural unit (c3) is 5. 6. The thermosetting resin composition according to claim 5, wherein the content of the structural unit (c4) is from 1 to 20% by mass. The thermosetting according to any one of claims 1 to 6, wherein the content of the component (B) is 40 to 90 parts by mass with respect to 100 parts by mass of the total resin component of the thermosetting resin composition. elastic resin composition. Any one of claims 1 to 7, wherein the content ratio of the (A1) component and the (A2) component [(A1) component/(A2) component] is 0.1 to 1 on a mass basis. The thermosetting resin composition according to Item . The thermosetting according to any one of claims 1 to 8, wherein the content of the component (C) is 5 to 50 parts by mass with respect to 100 parts by mass of the total resin component of the thermosetting resin composition. elastic resin composition. The thermosetting resin composition according to any one of claims 1 to 9, wherein the cured product does not have a phase separation structure. A prepreg containing the thermosetting resin composition according to any one of claims 1 to 10. A resin-coated metal foil obtained by laminating the thermosetting resin composition according to any one of claims 1 to 10 and a metal foil. A laminate comprising the prepreg according to claim 11 or the resin-coated metal foil according to claim 12. A printed wiring board comprising the laminate according to claim 13 . A semiconductor package comprising the printed wiring board according to claim 14 .