阅读说明：本技术 覆金属箔层压板、带树脂的金属箔及布线板 (Metal-clad laminate, metal foil with resin, and wiring board ) 是由 津田康介 斋藤宏典 藤原弘明 于 2018-06-22 设计创作，主要内容包括：一种覆金属箔层压板，包括：绝缘层、以及与所述绝缘层的至少一个表面接触而存在的金属箔，所述绝缘层包含树脂组合物的固化物，所述树脂组合物含有：在25℃的二氯甲烷中测得的特性粘数为0.03～0.12dl/g且每一分子在分子末端具有平均1.5～3个下述式(1)或下述式(2)所示的基团的聚苯醚共聚物、在分子末端具有2个以上碳?碳不饱和双键的热固性固化剂、以及热塑性弹性体，所述金属箔包括：金属基材、以及设置于所述金属基材的至少与所述绝缘层的接触面侧且包含钴的阻隔层，所述接触面的表面粗糙度以十点平均粗糙度Rz计为2μm以下。(A metal-clad laminate comprising: an insulating layer and a metal foil present in contact with at least one surface of the insulating layer, wherein the insulating layer contains a cured product of a resin composition containing: a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the following formula (1) or formula (2) per molecule at the molecular end, a thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at the molecular end, and a thermoplastic elastomer, wherein the metal foil comprises: and a barrier layer that is provided on at least a contact surface side of the metal base material with the insulating layer and that contains cobalt, wherein a surface roughness of the contact surface is 2 [ mu ] m or less in terms of a ten-point average roughness Rz.)

1. A metal-clad laminate characterized by comprising:

an insulating layer; and

a metal foil present in contact with at least one surface of the insulating layer, wherein,

the insulating layer contains a cured product of a resin composition,

the resin composition contains:

a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the following formula (1) or formula (2) at the molecular end per molecule,

A thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at the molecular terminal, and

a thermoplastic elastomer,

the metal foil includes:

metal base material, and

a barrier layer which is provided on at least a contact surface side of the metal base material with the insulating layer and contains cobalt,

the surface roughness of the contact surface is 2 [ mu ] m or less in terms of ten-point average roughness Rz,

in the formula (1), R₁R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms₂An alkylene group having 1 to 10 carbon atoms,

in the formula (2), R₃Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

2. The metal-clad laminate of claim 1, wherein:

the thermoplastic elastomer is a styrene thermoplastic elastomer.

3. The metal-clad laminate of claim 2, wherein:

the styrene-based thermoplastic elastomer is a thermoplastic elastomer obtained by hydrogenating a part or all of double bonds of at least one copolymer selected from a methylstyrene (ethylene/butylene) methylstyrene copolymer, a styrene (ethylene/propylene) styrene copolymer, a styrene (ethylene/butylene) styrene copolymer, a styrene (butadiene/isoprene) styrene copolymer, and a styrene isoprene styrene copolymer.

4. The metal-clad laminate of claim 2, wherein:

the styrene-based thermoplastic elastomer is at least one selected from the group consisting of a hydrogenated methylstyrene (ethylene/butylene) methylstyrene copolymer, a hydrogenated methylstyrene (ethylene-ethylene/propylene) methylstyrene copolymer, a hydrogenated styrene isoprene styrene copolymer, a hydrogenated styrene (ethylene/butylene) styrene copolymer, a hydrogenated styrene (ethylene/propylene) styrene copolymer, and a hydrogenated styrene (ethylene-ethylene/propylene) styrene copolymer.

5. The metal-clad laminate of any one of claims 1 to 4, wherein:

the ratio of the sum of the content of the polyphenylene ether copolymer and the content of the thermosetting curing agent to the content of the thermoplastic elastomer is 50: 50 to 90: 10 in terms of mass ratio.

6. The metal-clad laminate of any one of claims 1 to 5, wherein:

the resin composition further contains a silane coupling agent,

the silane coupling agent has at least one selected from the group consisting of a vinyl group, a styryl group, a methacryloyl group, and an acryloyl group in a molecule.

7. A resin-bearing metal foil, characterized by comprising:

an insulating adhesive layer; and

a metal foil present in contact with at least one surface of the insulating adhesive layer, wherein,

the insulating adhesive layer contains a resin composition or a semi-cured product of the resin composition,

the resin composition contains:

a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the following formula (1) or formula (2) at the molecular end per molecule,

A thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at the molecular terminal, and

a thermoplastic elastomer,

the metal foil includes:

metal base material, and

a barrier layer containing cobalt and provided on at least a contact surface side of the metal base material with the insulating adhesive layer,

the surface roughness of the contact surface is 2 [ mu ] m or less in terms of ten-point average roughness Rz,

in the formula (1), R₁R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms₂An alkylene group having 1 to 10 carbon atoms,

in the formula (2), R₃Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

8. A wiring board characterized by comprising:

an insulating layer; and

a wiring present in contact with at least one surface of the insulating layer, wherein,

the insulating layer contains a cured product of a resin composition,

the resin composition contains:

a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the following formula (1) or formula (2) at the molecular end per molecule,

A thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at the molecular terminal, and

a thermoplastic elastomer,

the metal foil includes:

metal base material, and

a barrier layer which is provided on at least a contact surface side of the metal base material with the insulating layer and contains cobalt,

the surface roughness of the contact surface is 2 [ mu ] m or less in terms of ten-point average roughness Rz,

in the formula (1), R₁Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R2 represents an alkylene group having 1 to 10 carbon atoms,

in the formula (2), R₃Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

Technical Field

The present invention relates to a metal foil-clad laminate, a resin-containing metal foil, and a wiring board.

Background

With the increase in the amount of information processing for various electronic devices, mounting technologies such as high integration of mounted semiconductor devices, high density wiring, and multi-layer wiring have been rapidly advancing. Further, as a wiring board used in various electronic devices, for example, a wiring board that is compatible with high frequencies such as a millimeter wave radar board used in a vehicle is demanded.

When a signal is transmitted to a wiring provided in a wiring board, a transmission loss due to a conductor forming the wiring, a transmission loss due to a dielectric material around the wiring, and the like occur. In order to increase the transmission speed of signals, a wiring board is required to reduce loss during signal transmission. It is also known that these transmission losses are particularly likely to occur when high-frequency signals are transmitted to the wiring provided in the wiring board. Therefore, a reduction in transmission loss is more required for a wiring board that can cope with high frequencies. In order to satisfy such a requirement, it is conceivable to use a material having a low dielectric constant and a low dielectric loss tangent as an insulating layer in the wiring board.

On the other hand, a metal-clad laminate and a resin-coated metal foil used in the production of a wiring board or the like include not only an insulating layer but also a metal foil on the insulating layer. The wiring board is not limited to the insulating layer, and includes a wiring such as a wiring derived from a metal foil on the insulating layer. As metal-clad laminates and resin-attached metal foils that focus on such metal foils, for example, the metal-clad laminates and resin-attached metal foils described in patent document 1 can be cited.

Patent document 1 describes a metal-clad laminate and a metal foil with resin, which include: and a metal foil fixed (adhered) to one or both surfaces of the insulating resin composition layer, wherein the metal foil is surface-treated on at least the insulating resin composition layer side of the metal foil, and the metal foil is not substantially roughened on both surfaces of the metal foil.

Patent document 1 discloses the following: the adhesion and the flatness of the interface between the insulating resin composition layer and the metal foil can be both satisfied, and the practical requirements for manufacturing a printed wiring board can be satisfied.

In order to increase the signal transmission speed, the wiring board is further required to reduce loss during signal transmission. Further, the wiring board is also required to have high reliability such that the wiring does not peel off from the insulating layer even when heat or moisture is absorbed. Therefore, the metal-clad laminate and the metal foil with resin are required to have high adhesion between the metal foil and the insulating layer and to suppress a decrease in adhesion between the metal foil and the insulating layer due to heating and moisture absorption.

Disclosure of Invention

In view of the above circumstances, an object of the present invention is to provide: a metal foil-clad laminate, a resin-containing metal foil, and a wiring board, in which loss during signal transmission is reduced, the adhesion between the metal foil and the insulating layer is high, and the reduction in adhesion between the metal foil and the insulating layer due to heating and moisture absorption is sufficiently suppressed.

One aspect of the present invention relates to a metal-clad laminate comprising: an insulating layer; and a metal foil present in contact with at least one surface of the insulating layer, wherein the insulating layer contains a cured product of a resin composition containing: a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the following formula (1) or formula (2) per molecule at the molecular end, a thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at the molecular end, and a thermoplastic elastomer, wherein the metal foil comprises: and a barrier layer that is provided on at least a contact surface side of the metal base material with the insulating layer and that contains cobalt, wherein a surface roughness of the contact surface is 2 [ mu ] m or less in terms of a ten-point average roughness Rz.

In the formula (1), R₁R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms₂Represents an alkylene group having 1 to 10 carbon atoms.

In the formula (2), R₃Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

Further, another aspect of the present invention relates to a metal foil with resin, comprising: an insulating adhesive layer; and a metal foil present in contact with at least one surface of the insulating adhesive layer, wherein the insulating adhesive layer contains a resin composition or a semi-cured product of the resin composition, and the resin composition contains: a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the formula (1) or the formula (2) per molecule at a molecular end, a thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at a molecular end, and a thermoplastic elastomer, the metal foil comprising: and a barrier layer which is provided on at least the contact surface side of the metal base material with the insulating adhesive layer and contains cobalt, wherein the surface roughness of the contact surface is 2 [ mu ] m or less in terms of ten-point average roughness Rz.

Further, another aspect of the present invention relates to a wiring board, including: an insulating layer; and a wiring which is present in contact with at least one surface of the insulating layer, wherein the insulating layer contains a cured product of a resin composition containing: a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the formula (1) or the formula (2) per molecule at a molecular end, a thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at a molecular end, and a thermoplastic elastomer, the metal foil comprising: and a barrier layer that is provided on at least a contact surface side of the metal base material with the insulating layer and that contains cobalt, wherein a surface roughness of the contact surface is 2 [ mu ] m or less in terms of a ten-point average roughness Rz.

The above objects, features, and other objects, features, and advantages of the present invention will become more apparent from the following detailed description.

Drawings

Fig. 1 is a cross-sectional view showing a structure of a metal-clad laminate according to an embodiment of the present invention.

Fig. 2 is a sectional view showing a structure of a resin-attached metal foil according to another embodiment of the present invention.

Fig. 3 is a cross-sectional view showing a structure of a wiring board according to another embodiment of the present invention.

Detailed Description

The present inventors have focused on a wiring formed on an insulating layer in order to reduce loss during signal transmission in a wiring board.

Specifically, first, the present inventors presume that: when a signal transmitted through a wiring is a high-frequency signal, the signal is concentrated near the surface of a conductor constituting the wiring due to the skin effect. On the other hand, for metal-clad laminates and resin-coated metal foils, it is generally known that: in order to improve the adhesion strength between the metal foil and the insulating layer, the surface of the metal foil in contact with the insulating layer (contact surface) is roughened. For wiring boards, it is known that: in order to improve the adhesion strength between the wiring and the insulating layer, the wiring having a roughened contact surface is used. Despite the above circumstances, the present inventors have studied to reduce the surface roughness of a metal foil or wiring. The present inventors believe that: this smoothes the surface of the wiring, and shortens the transmission distance of signals flowing near the surface of the wiring. Namely, the present inventors have found that: the loss during signal transmission can be reduced by improving the smoothness of the surface of the wiring provided on the insulating layer of the wiring board, which is in contact with the insulating layer, without changing the composition of the insulating layer of the wiring board.

In addition, as a metal foil used for a metal-clad laminate and a metal foil with resin, if the metal foil is subjected to a surface treatment, a plating treatment is often performed using nickel having high heat resistance. Patent document 1 also reports: the surface of the metal foil is subjected to rust prevention treatment mainly with nickel. As described above, the present inventors have considered that signals are concentrated in the vicinity of the surface of a conductor constituting a wiring, and have studied to use cobalt having a lower resistance than nickel in a barrier layer provided on the surface of a metal foil or a wiring.

On the other hand, cobalt has a lower heat resistance than nickel. Therefore, the present inventors have studied using, as an insulating layer, an insulating layer containing a cured product obtained by curing a resin composition having excellent heat resistance. The present inventors believe that: by doing so, even if a metal foil having a barrier layer containing cobalt having a lower heat resistance than nickel is used, the heat resistance of the insulating layer in contact with the metal foil is high, and therefore the heat resistance of the metal-clad laminate and the metal foil with resin obtained can be sufficiently maintained. Further, the present inventors considered that, as for a cured product contained in an insulating layer: the insulating layer obtained by containing a component derived from polyphenylene ether having a low dielectric constant and a low dielectric loss tangent has excellent dielectric characteristics. Thus, the present inventors believe that: the metal foil-clad laminate and the resin-coated metal foil provided with such an insulating layer can improve heat resistance and further reduce loss during signal transmission.

In addition, the present inventors found in their research that: depending on the cured product contained in the insulating layer, after the obtained wiring board is heated or absorbs moisture, the adhesion strength between the wiring and the insulating layer is reduced, and in some cases, the wiring may be peeled off. Thus, the present inventors have found that: by using a cured product of the following resin composition containing a thermoplastic elastomer as a cured product contained in the insulating layer, the adhesion between the metal foil and the insulating layer can be improved, and the adhesion between the metal foil and the insulating layer can be prevented from being lowered due to heating and moisture absorption.

The present inventors have conducted various studies as described above, and as a result, have found that: the above object can be achieved by the present invention which provides a metal foil-clad laminate, a resin-containing metal foil, and a wiring board, in which loss during signal transmission is reduced, the adhesion between the metal foil and the insulating layer is high, and the reduction in adhesion between the metal foil and the insulating layer due to heating and moisture absorption is sufficiently suppressed, and the present invention has been completed as described below.

Embodiments according to the present invention will be described below, but the present invention is not limited to these embodiments.

A metal-clad laminate according to an embodiment of the present invention includes: an insulating layer; and a metal foil present in contact with at least one surface of the insulating layer. As shown in fig. 1, the metal-clad laminate 11 includes an insulating layer 12 and a metal foil 13, and the metal foil 13 is disposed so as to be in contact with both surfaces of the insulating layer 12. The metal foil-clad laminate may further include a metal foil in contact with only one surface of the insulating layer. Fig. 1 is a cross-sectional view showing the structure of the metal-clad laminate 11 according to the present embodiment.

The insulating layer 12 includes a cured product of a resin composition containing: a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the following formula (1) or formula (2) per molecule at the molecular end, a thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at the molecular end, and a thermoplastic elastomer.

In the formula (1), R₁R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms₂Represents an alkylene group having 1 to 10 carbon atoms.

In the formula (2), R₃Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

The insulating layer 12 is not particularly limited as long as it contains a cured product of the resin composition. The insulating layer 12 may be a layer composed of only a cured product of the resin composition, or may be a layer containing not only a cured product of the resin composition but also a fibrous substrate, for example. The insulating layer 12 can be improved in strength, heat resistance, and the like by including a fibrous base material. Specific examples of the insulating layer containing a fibrous substrate include: and a layer obtained by impregnating the resin composition into a fibrous substrate and curing the resin composition impregnated into the fibrous substrate.

The insulating layer 12 contains a cured product of the resin composition. The resin composition comprises the polyphenylene ether copolymer and the thermosetting curing agent. The polyphenylene ether copolymer is excellent in dielectric characteristics and can be cured by reaction with the thermosetting curing agent, and therefore the insulating layer 12 includes a cured product excellent in dielectric characteristics. Since the thermoplastic elastomer is contained in the resin composition, the thermoplastic elastomer is also contained in the insulating layer 12. Thus, the insulating layer 12 can be formed to have a high adhesion between the metal foil and the insulating layer and to suppress a decrease in adhesion between the metal foil and the insulating layer due to heating and moisture absorption.

Further, the metal foil 13 includes: a metal base 14, and a barrier layer 15 provided on at least a contact surface 16 side of the metal base 14 with the insulating layer 12. As shown in fig. 1, the metal foil 13 includes a metal base 14 and a barrier layer 15, and the barrier layer 15 is provided on a contact surface 16 side of the metal base 14 with the insulating layer 12. The metal foil may have the barrier layer on both sides of the metal base material. The surface roughness of the contact surface 16 is 2 μm or less in terms of ten-point average roughness Rz.

The metal foil 13 is in contact with the insulating layer 12. That is, the insulating layer 12 is in contact with the barrier layer 15 of the metal foil 13. The metal foil 13 serves as a wiring in the wiring board when the wiring board is manufactured from the metal-clad laminate 11. Since the surface roughness of the metal foil 13 that can be used as the wiring is low at the contact surface 16 with the insulating layer 12 as described above, the surface roughness of the wiring at the contact surface with the insulating layer is also low. Thus, it is believed that: the wiring board obtained from the metal-clad laminate 11 has high smoothness of the interface between the insulating layer and the wiring. Thus, it is believed that: in the wiring board, conductor loss due to contact between the wiring and the insulating layer is reduced. Thus, it is believed that: the metal foil-clad laminate 11 can provide a wiring board with reduced loss during signal transmission.

As described above, the metal foil 13 includes the barrier layer 15 containing cobalt on the contact surface 16 side. From this point of view, it is considered that the loss at the time of signal transmission can also be reduced. Further, it is considered that: the barrier layer 15 containing cobalt has excellent adhesion to the insulating layer 12. Thus, it is believed that: even if the smoothness of the contact surface 16 of the metal foil 13 with the insulating layer 12 is improved, the adhesion between the metal foil 13 and the insulating layer 12 can be sufficiently ensured. Therefore, the wiring board manufactured using the metal-clad laminate 11 can suppress peeling of the wiring from the insulating layer. From this point of view, the metal foil clad laminate 11 can also produce a good wiring board.

From the above, it can be seen that: the metal-clad laminate 11 thus obtained is a metal-clad laminate which can favorably produce a wiring board with reduced loss during signal transmission. In addition, in the metal-clad laminate 11, not only a wiring board with reduced loss during signal transmission can be favorably manufactured, but also the adhesive strength between the metal foil and the insulating layer is high, and the decrease in the adhesive strength between the metal foil and the insulating layer due to heating and moisture absorption is sufficiently suppressed. Accordingly, since the metal-clad laminate 11 is a metal-clad laminate that is less likely to cause a failure due to heating or the like and has high reliability, a highly reliable wiring board can be manufactured.

As described above, the surface roughness of the contact surface 16 of the metal foil 13 is 2 μm or less, preferably 1.5 μm or less, and more preferably 1 μm or less. The lower the surface roughness of the contact surface 16, that is, the higher the smoothness of the metal foil 13, the more preferable the surface roughness is in terms of reducing the loss during signal transmission as described above. On the other hand, even if the surface roughness of the contact surface 16 is reduced, the ten-point average roughness Rz is about 0.5 μm, which is a limit. Further, if the surface roughness of the contact surface 16 is too low, adhesion between the metal foil 13 and the insulating layer 12 tends to be reduced even if a barrier layer containing cobalt is provided. From this point of view, the surface roughness of the contact surface 16 is preferably 0.5 μm or more in terms of ten-point average roughness Rz. Therefore, the surface roughness of the contact surface 16 is preferably 0.5 to 2 μm, more preferably 0.6 to 1.5 μm, and still more preferably 0.6 to 1 μm in terms of ten-point average roughness Rz. Further, since the metal foil 13 includes a metal base 14 and a barrier layer 15 containing cobalt and provided on the contact surface 16 side of the metal base 14, the surface roughness of the contact surface 16 is the surface roughness of the barrier layer 15. The surface roughness of the metal base material 14 is not particularly limited. Even if the barrier layer 15 is formed, the surface roughness of the metal base 14 is preferably the same as the surface roughness of the contact surface 16 (the barrier layer 15) when the surface roughness of the metal foil 13 is not significantly changed.

The metal base 14 is not particularly limited as long as it is a metal base used as a metal foil of the metal foil-clad laminate. Specifically, examples of the metal base 14 include copper foil, nickel foil, and aluminum foil. Among these, copper foil is preferably used as the metal base 14.

The barrier layer 15 is not particularly limited as long as it is a layer containing cobalt. The barrier layer 15 may contain cobalt, and may contain a metal other than cobalt (other metal) within a range not impairing the effect of the present invention. Examples of the other metal include nickel, tin, zinc, and chromium, and it is preferable that nickel and tin having high electric resistance are not contained as much as possible. Further, examples of the barrier layer 15 include: a layer formed by plating the metal base (metal foil before the barrier layer is provided) 14. Examples of the plating treatment include sputtering treatment, electrolytic plating treatment, and electroless plating treatment using cobalt or an alloy containing cobalt. Further, before forming the barrier layer containing cobalt as described above, the metal base (metal foil before providing the barrier layer) 14 such as copper foil may be subjected to rust prevention treatment such as chromate treatment separately in order to prevent surface oxidation.

The thickness of the metal foil 13 is not particularly limited, and varies depending on the performance required for the wiring board to be finally obtained. The thickness of the metal foil 13 is preferably 12 to 70 μm, for example.

As the metal foil 13, a commercially available metal foil can be used. Examples of commercially available metal foils include cobalt-plated copper foils manufactured by fuda metal foil powder industries. More specifically, T9FZ-SV [ Rz: 1.6 μm, thickness 18 μm ] and T9DA-SV [ Rz: 1.0 μm, thickness 18 μm ], and the like.

As described above, the cured product contained in the insulating layer 12 is a cured product obtained by curing the resin composition. The resin composition further contains the polyphenylene ether copolymer, the thermosetting curing agent and the thermoplastic elastomer. The components contained in the resin composition will be described below.

The polyphenylene ether copolymer used in the present embodiment is a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the formula (1) or the formula (2) at the molecular end per molecule.

In the formula (1), R₁Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. The alkyl group having 1 to 10 carbon atoms is not particularly limited as long as it is an alkyl group having 1 to 10 carbon atoms, and may be a straight alkyl groupThe polymer may be linear or branched. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, and hexyl groups. Among them, a hydrogen atom is preferable. R₂Represents an alkylene group having 1 to 10 carbon atoms. The alkylene group having 1 to 10 carbon atoms is not particularly limited as long as it is an alkylene group having 1 to 10 carbon atoms, and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, and a decylene group. Among them, methylene is preferred.

The group represented by the formula (1) is not particularly limited, and p-vinylbenzyl (p-vinylbenzyl group) and m-vinylbenzyl (m-vinylbenzyl group) are preferable.

In the formula (2), R₃Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. The alkyl group having 1 to 10 carbon atoms is not particularly limited as long as it is an alkyl group having 1 to 10 carbon atoms, and may be straight or branched, and specific examples thereof include the above R₁The same alkyl group. As R₃Preferably methyl.

The group represented by the formula (2) is not particularly limited, and for example, an acrylate group and a methacrylate group are preferable.

The groups represented by the formula (1) or the formula (2) may be used alone or in combination of two or more.

Further, the polyphenylene ether copolymer preferably has a group represented by the above formula (2). By using such a polyphenylene ether copolymer, a metal foil-clad laminate in which the decrease in adhesion between the metal foil and the insulating layer due to heating and moisture absorption is further suppressed can be obtained.

The intrinsic viscosity of the polyphenylene ether copolymer used in the present embodiment is 0.03 to 0.12dl/g, preferably 0.04 to 0.11dl/g, and more preferably 0.06 to 0.095 dl/g. If the intrinsic viscosity is too low, the molecular weight tends to be low, and it tends to be difficult to obtain a low dielectric constant, a low dielectric loss tangent, or the like. Further, if the intrinsic viscosity is too high, the viscosity becomes high, and it becomes difficult to obtain sufficient fluidity, and the moldability of the cured product tends to be low. Therefore, when the intrinsic viscosity of the polyphenylene ether copolymer is within the above range, excellent heat resistance and moldability of the cured product can be achieved.

The intrinsic viscosity herein is an intrinsic viscosity measured in methylene chloride at 25 ℃, and more specifically, for example, a value measured by a viscometer to obtain a 0.18g/45ml methylene chloride solution (liquid temperature 25 ℃). Examples of the viscometer include AVS500 Visco System manufactured by schottky (Schott) corporation.

Further, the average number of groups represented by the formula (1) or the formula (2) (the number of terminal functional groups) per molecule of the polyphenylene ether copolymer used in the present embodiment is 1.5 to 3, preferably 1.5 to 2. If the number of terminal functional groups is too small, it tends to be difficult to obtain sufficient heat resistance of the cured product. Further, if the number of terminal functional groups is too large, the reactivity becomes too high, and there is a possibility that problems such as a decrease in storage stability of the resin composition or a decrease in flowability of the resin composition may occur. That is, if such a modified polyphenylene ether is used, there is a possibility that molding defects such as voids are generated at the time of multilayer molding, which causes a problem of moldability due to insufficient fluidity or the like, and it is difficult to obtain a highly reliable wiring board.

The number of terminal functional groups of the polyphenylene ether copolymer may be represented by the following average value: an average value of the groups represented by the aforementioned formula (1) or the aforementioned formula (2) per molecule of all polyphenylene ether copolymers present in 1 mole of polyphenylene ether copolymer. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the resulting polyphenylene ether copolymer and calculating the amount of decrease from the number of hydroxyl groups in the polyphenylene ether before modification (before bonding of the group represented by the formula (1) or the formula (2)). The amount of decrease from the number of hydroxyl groups of the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in the polyphenylene ether copolymer can be determined by adding a quaternary ammonium salt (tetraethylammonium hydroxide) associated with hydroxyl groups to a solution of the polyphenylene ether copolymer and measuring the UV absorbance of the mixed solution.

The polyphenylene ether copolymer according to the present embodiment preferably has a polyphenylene ether chain in a molecule, for example, a repeating unit (repeating unit) represented by the following formula (3) in a molecule.

In the formula (3), m represents 1 to 50. Furthermore, R₄～R₇Each independently. Namely, R₄～R₇The groups may be the same or different. Furthermore, R₄～R₇Represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group or an alkynylcarbonyl group. Among them, hydrogen atom and alkyl group are preferable.

R₄～R₇Specific examples of the functional groups include the following groups.

The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples thereof include methyl, ethyl, propyl, hexyl and decyl groups.

The alkenyl group is not particularly limited, and is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples thereof include vinyl, allyl and 3-butenyl groups.

The alkynyl group is not particularly limited, and is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples thereof include ethynyl and prop-2-yn-1-yl (propargyl).

The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, and for example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferable, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferable. Specific examples thereof include acetyl, propionyl, butyryl, isobutyryl, pivaloyl, hexanoyl, octanoyl, and cyclohexylcarbonyl.

The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, and is preferably an alkenylcarbonyl group having 3 to 18 carbon atoms, and more preferably an alkenylcarbonyl group having 3 to 10 carbon atoms. Specific examples thereof include acryloyl, methacryloyl and crotonyl groups.

The alkynyl carbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, and for example, an alkynyl carbonyl group having 3 to 18 carbon atoms is preferable, and an alkynyl carbonyl group having 3 to 10 carbon atoms is more preferable. Specific examples thereof include a propioyl group and the like.

Further, as the polyphenylene ether copolymer used in the present embodiment, for example, a compound in which a group represented by the formula (1) or the formula (2) is provided at the end of a polyphenylene ether represented by any one of the following formula (4), the following formula (6), and the following formula (7) can be cited. Specifically, modified polyphenylene ethers represented by the following formulae (8) to (13) are exemplified.

In the formula (4), s and t are preferably, for example, a total value of s and t is 1 to 30. In addition, s is preferably 0 to 20, and t is preferably 0 to 20. That is, s is preferably 0 to 20, t is preferably 0 to 20, and the total of s and t is preferably 1 to 30. Y represents a linear, branched or cyclic hydrocarbon group. Further, Y represents, for example, a group represented by the following formula (5).

In the formula (5), R₉And R₁₀Each independently represents a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group and the like. Examples of the group represented by formula (5) include methylene, methylmethylene, and dimethylmethylene.

In the formulae (6) and (7), s and t are the same as those in the formula (4).

In the formula (8), s and t are the same as s and t in the formula (4), and Y is the same as Y in the formula (4). In the formula (8), R₁And R₂With R of the above formula (1)₁And R₂The same is true.

In the formulae (9) and (10), s and t are the same as those in the formula (4). In the formulae (9) and (10), R₁And R₂With R of the above formula (1)₁And R₂The same is true.

In the formula (11), s and t are the same as s and t in the formula (4), and Y is the same as Y in the formula (4). In the formula (11), R₃With R of the above formula (2)₃The same is true.

In the formulae (12) and (13), s and t are the same as those in the formula (4). In the formulae (12) and (13), R₃With R of the above formula (2)₃The same is true.

The weight average molecular weight (Mw) of the polyphenylene ether copolymer used in the present embodiment is not particularly limited. Specifically, the concentration is preferably 500 to 5000, more preferably 800 to 4000, and still more preferably 1000 to 3000. Here, the weight average molecular weight is a value measured by a general molecular weight measurement method, and specifically, a value measured by Gel Permeation Chromatography (GPC) or the like can be mentioned. Further, in the case where the polyphenylene ether copolymer has a repeating unit represented by the formula (3) in the molecule, m is preferably a value such that the weight average molecular weight of the polyphenylene ether copolymer falls within the above range. Specifically, m is preferably 1 to 50.

When the weight average molecular weight of the polyphenylene ether copolymer is within the above range, the polyphenylene ether copolymer will have excellent dielectric properties possessed by polyphenylene ether, and not only will the cured product be more excellent in heat resistance, but also the moldability is excellent. This is considered to be based on the following. In general polyphenylene ethers, if the weight average molecular weight is within the above range, the molecular weight is relatively low, and therefore the heat resistance of the cured product tends to decrease. In this regard, it is believed that: the polyphenylene ether copolymer used in the present embodiment has a group represented by the formula (1) or the formula (2) at the end, and therefore a cured product can obtain sufficiently high heat resistance. Further, it is considered that: when the weight average molecular weight of the polyphenylene ether copolymer is within the above range, the molecular weight is relatively low and the moldability is also excellent. Thus, it is believed that: by using such a polyphenylene ether copolymer, a polyphenylene ether copolymer having excellent moldability as well as excellent heat resistance of a cured product can be obtained.

The method for synthesizing the polyphenylene ether copolymer used in the present embodiment is not particularly limited as long as the polyphenylene ether copolymer having a group represented by the formula (1) or the formula (2) at the terminal can be synthesized.

The thermosetting curing agent used in the present embodiment is not particularly limited as long as it has 2 or more carbon-carbon unsaturated double bonds at the molecular end. Examples of the carbon-carbon unsaturated double bond include double bonds contained in an allyl group, a vinyl group, an acrylate group, a methacrylate group, and a maleimide group. The thermosetting curing agent may be any curing agent which reacts with the carbon-carbon unsaturated double bond and the polyphenylene ether copolymer to form a crosslink and cures the same. The resin composition according to the present embodiment may contain the thermosetting curing agent, and may contain a curing agent other than the thermosetting curing agent.

Specific examples of the thermosetting curing agent include: polyfunctional allyl compounds having 2 or more allyl groups only at the molecular terminal, such as triallyl isocyanurate (TAIC), polyfunctional methacrylate compounds having 2 or more methacryloyl groups only at the molecular terminal, such as trimethylolpropane trimethacrylate (TMPT), polyfunctional acrylate compounds having 2 or more acryloyl groups only at the molecular terminal, vinylbenzyl compounds such as Divinylbenzene (DVB) having a vinylbenzyl group in the molecule, and polyfunctional maleimide compounds having 2 or more maleimide groups at the molecular terminal, and the like. In addition, as the thermosetting curing agent, the thermosetting curing agents exemplified above may be used alone, or two or more kinds may be used in combination.

The thermosetting curing agent preferably has a weight average molecular weight of 100 to 5000, more preferably 100 to 4000, and still more preferably 100 to 3000. If the weight average molecular weight of the thermosetting curing agent is too low, the thermosetting curing agent may easily volatilize from the compounding ingredient system of the resin composition. Further, if the weight average molecular weight of the thermosetting curing agent is too high, the viscosity of the varnish of the resin composition or the melt viscosity at the time of thermoforming may become too high. Therefore, if the weight average molecular weight of the thermosetting curing agent is within the above range, a resin composition having a cured product with more excellent heat resistance can be obtained. The reason is considered to be that: by the reaction with the polyphenylene ether copolymer, a crosslink can be formed well. Here, the weight average molecular weight is a value measured by a general molecular weight measurement method, and specifically, a value measured by Gel Permeation Chromatography (GPC) or the like is exemplified.

In addition, the thermosetting curing agent has an average number of carbon-carbon unsaturated double bonds (the number of terminal functional groups) per molecule of the thermosetting curing agent of 2 or more, preferably 2 to 20, and more preferably 2 to 18 as described above. If the number of terminal functional groups is too small, it tends to be difficult to obtain sufficient heat resistance of the cured product. Further, if the number of terminal functional groups is too large, the reactivity becomes too high, and there is a possibility that problems such as a decrease in storage stability of the resin composition or a decrease in flowability of the resin composition may occur.

Note that the number of terminal functional groups herein is known from the specification value of the thermosetting curing agent product used. Specific examples of the number of terminal functional groups herein include the following average values: average value of carbon-carbon unsaturated double bonds per molecule of all thermosetting curing agents present in 1 mole of the thermosetting curing agent.

The thermoplastic elastomer used in the present embodiment is not particularly limited, and a styrene-based thermoplastic elastomer is preferable. Further, as the styrene-based thermoplastic elastomer, it is preferable that the repeating unit having a carbon-carbon unsaturated double bond other than an aromatic ring is less than 10 mol% with respect to the total repeating units. That is, the styrene-based thermoplastic elastomer is preferably a styrene-based thermoplastic elastomer in which the mole number is less than 10 mol% when the mole number of the carbon-carbon unsaturated double bond other than the aromatic ring is expressed by 1 mol in the styrene-based thermoplastic elastomer. The method of calculating the molar ratio of the carbon-carbon unsaturated double bonds present (total ratio of all the carbon-carbon unsaturated double bonds present) can be calculated, for example, by the following method: the ratio of the repeating units having carbon-carbon unsaturated double bonds other than the aromatic ring to the total repeating units was determined. The styrene-based thermoplastic elastomer is preferably one having a repeating unit having a carbon-carbon unsaturated double bond other than an aromatic ring in an amount of less than 10 mol%, more preferably 0 to 5 mol%, and still more preferably 0 to 2 mol% based on the total repeating units. Further, the content is particularly preferably 0 mol% because the smaller the number of carbon-carbon unsaturated double bonds other than aromatic rings contained in the styrene-based thermoplastic elastomer, the better. Further, by including the thermoplastic elastomer in the resin composition, the insulating layer 12 can be formed to have a high adhesive strength between the metal foil and the insulating layer, and a layer in which a decrease in the adhesive strength between the metal foil and the insulating layer due to heating and moisture absorption is suppressed. Further, by using a styrene-based thermoplastic elastomer in which the repeating unit having a carbon-carbon unsaturated double bond other than an aromatic ring is less than 10 mol% relative to the total repeating units, the occurrence of thermal deterioration of dielectric characteristics can be suppressed.

The carbon-carbon unsaturated double bonds contained in the styrene-based thermoplastic elastomer include not only carbon-carbon unsaturated double bonds present at the molecular terminals but also carbon-carbon unsaturated double bonds contained in the molecular chain. That is, the repeating unit having a carbon-carbon unsaturated double bond other than an aromatic ring includes: carbon-carbon unsaturated double bonds present at the molecular terminals and carbon-carbon unsaturated double bonds contained in the molecular chain. In the styrene-based thermoplastic elastomer, the smaller the number of carbon-carbon unsaturated double bonds contained in the molecular chain, the more preferable the amount of carbon-carbon unsaturated double bonds other than aromatic rings is, from the viewpoint of suppressing the occurrence of thermal deterioration of dielectric properties. Specifically, the styrene-based thermoplastic elastomer is preferably such that the repeating unit having a carbon-carbon double bond contained in the molecular chain in the repeating unit having a carbon-carbon unsaturated double bond other than an aromatic ring is less than 3 mol%, preferably 0 to 2 mol% or less, and more preferably 0 to 1 mol% or less, based on the total repeating units. If such a styrene-based thermoplastic elastomer having the presence ratio of carbon-carbon unsaturated double bonds in the molecular chain (presence ratio in the molecular chain) within the above range is used, the occurrence of thermal deterioration of dielectric characteristics can be further suppressed. Examples of the carbon-carbon unsaturated double bond contained in the molecular chain other than the aromatic ring include a vinylidene group.

Examples of the thermoplastic elastomer include hydrogenated styrene-based thermoplastic elastomers, and more specifically, include: hydrogenated styrene-based thermoplastic elastomers and the like having a content ratio of repeating units having a carbon-carbon unsaturated double bond of less than 10 mol% with respect to the total repeating units. Further, as the thermoplastic elastomer, specifically, there can be mentioned: thermoplastic elastomers in which a part or all of double bonds of at least one copolymer selected from the group consisting of a methylstyrene (ethylene/butylene) methylstyrene copolymer, a styrene (ethylene/propylene) styrene copolymer, a styrene (ethylene/butylene) styrene copolymer, a styrene (butadiene/isoprene) styrene copolymer and a styrene isoprene styrene copolymer are hydrogenated, and the like. Further, as the aforementioned thermoplastic elastomer, more specifically, there can be mentioned: hydrogenated methylstyrene (ethylene/butylene) methylstyrene copolymer, hydrogenated methylstyrene (ethylene-ethylene/propylene) methylstyrene copolymer, hydrogenated styrene isoprene styrene copolymer, hydrogenated styrene (ethylene/butylene) styrene copolymer, hydrogenated styrene (ethylene/propylene) styrene copolymer, hydrogenated styrene (ethylene-ethylene/propylene) styrene copolymer, and the like. The thermoplastic elastomers described above may be used alone or in combination of two or more.

The weight average molecular weight of the thermoplastic elastomer is preferably 10000 to 300000, more preferably 50000 to 250000, and further preferably 60000 to 200000. If the molecular weight of the thermoplastic elastomer is too small, the glass transition temperature of the cured product tends to be low, or the heat resistance of the cured product tends to be low. Further, if the molecular weight of the thermoplastic elastomer is too large, the viscosity of the varnish of the resin composition or the melt viscosity during thermoforming may become too high. Therefore, if the weight average molecular weight of the thermoplastic elastomer is within the above range, the glass transition temperature and the heat resistance are further excellent, and the decrease in the adhesive strength between the metal foil and the insulating layer due to heating and moisture absorption can be further suppressed.

The content of the polyphenylene ether copolymer is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, based on 100 parts by mass of the total of the polyphenylene ether copolymer, the thermosetting curing agent and the thermoplastic elastomer.

The content of the thermosetting cured product is preferably 10 to 50 parts by mass, more preferably 20 to 40 parts by mass, based on 100 parts by mass of the total of the polyphenylene ether copolymer, the thermosetting curing agent, and the thermoplastic elastomer.

When the content of the polyphenylene ether copolymer and the content of the thermosetting curing agent are either too small or too large, it tends to be difficult to obtain a good cured product. Specifically, the ratio of the content of the polyphenylene ether copolymer to the content of the thermosetting curing agent is preferably 50: 50 to 90: 10 in terms of mass ratio. If the content of the polyphenylene ether copolymer is too small, the excellent dielectric characteristics of polyphenylene ether tend not to be sufficiently exhibited. Further, if the content of the polyphenylene ether copolymer is too large, the glass transition temperature of the cured product tends to be low. Therefore, if the content of the polyphenylene ether copolymer and the content of the thermosetting curing agent are each within the above range, the curing reaction of the polyphenylene ether copolymer and the thermosetting curing agent proceeds well, and a cured product having excellent dielectric characteristics and a high glass transition temperature can be obtained.

Further, the ratio of the sum of the content of the polyphenylene ether copolymer and the content of the thermosetting curing agent to the content of the thermoplastic elastomer is preferably 50: 50 to 90: 10, and more preferably 75: 25 to 90: 10 in terms of mass ratio. That is, the content of the thermoplastic elastomer is preferably 10 to 50 parts by mass, and more preferably 10 to 25 parts by mass, based on 100 parts by mass of the total of the polyphenylene ether copolymer, the thermosetting curing agent, and the thermoplastic elastomer. If the content of the thermoplastic elastomer is too small, the following effects tend not to be sufficiently exhibited: that is, the adhesive strength between the metal foil and the insulating layer is high, and the decrease in the adhesive strength between the metal foil and the insulating layer due to heating and moisture absorption is suppressed. Further, if the content of the thermoplastic elastomer is too large, the viscosity of the resin composition tends to be high, and the permeability into a fibrous substrate or the like tends to be low.

The organic peroxide may be, for example, α ' -bis (t-butylperoxy-m-isopropyl) benzene, dicumyl peroxide, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane, di-t-butyl peroxide, 2, 5-dimethyl-2, 5-di (t-butylperoxy) -3-hexyne, benzoyl peroxide, 3 ', 5, 5 ' -tetramethyl-1, 4-diphenoquinone, tetrachlorobenzoquinone, 2, 4, 6-tri-t-butylphenoxy, t-butylperoxy-isopropyl monocarbonate, and azobisisobutyronitrile, and the organic peroxide is preferably a dialkyl organic peroxide from the viewpoint of the reaction initiation temperature, and in the above examples, α ' -bis (t-butylperoxy-m-isopropyl) benzene, α ' -bis (t-butylperoxy-m-isopropyl) benzene is preferably used because the reaction initiation temperature is relatively high, and the drying stability of the prepreg is not lowered, and the prepreg can be used alone or in combination with the curing reaction of the thermosetting curing agent.

The content of the organic peroxide is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 2 parts by mass, based on 100 parts by mass of the total of the polyphenylene ether copolymer, the thermosetting curing agent and the thermoplastic elastomer. If the content of the organic peroxide is too small, the effect of containing the organic peroxide tends to be not sufficiently exhibited. Further, if the content of the organic peroxide is too large, the dielectric properties and heat resistance of the resulting cured product tend to be adversely affected.

The resin composition according to the present embodiment may contain a flame retardant. The flame retardancy of a cured product of the resin composition can be improved by including a flame retardant. The flame retardant is not particularly limited. Specifically, in the field of using a halogen-based flame retardant such as a bromine-based flame retardant, for example: ethylene bis-pentabromobenzene (ethylene bis-bromobenzene) with melting point above 300 deg.C, ethylene bis-tetrabromo-imide (ethylene bis-bromoimide), decabromodiphenyl ether, and tetradecylbenzoxy benzene. Consider that: by using a halogen flame retardant, halogen desorption at high temperature can be suppressed, and a decrease in heat resistance can be suppressed. Further, in the field where halogen-free is required, there are listed: a phosphate flame retardant, a phosphazene flame retardant, a bis-diphenylphosphine oxide flame retardant, and a phosphinate flame retardant. Specific examples of the phosphate-based flame retardant include condensed phosphates of dixylyl phosphate. Specific examples of the phosphazene flame retardant include phenoxyphosphazene. Specific examples of the bisdiphenylphosphineoyl flame retardant include xylylene bis (diphenylphosphineoyl) oxide. Specific examples of the phosphinate flame retardant include metal phosphinates of dialkylaluminum phosphinate salts. As the flame retardant, each of the exemplified flame retardants may be used alone, or two or more kinds may be used in combination.

The resin composition according to the present embodiment may further contain additives such as a silane coupling agent, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or pigment, a lubricant, and an inorganic filler, as necessary, within a range not to impair the effects of the present invention. In particular, the silane coupling agent is preferably used for improving adhesion to a metal foil or adhesion between resins, and is preferably a coupling agent having a carbon-carbon unsaturated double bond. Examples of the silane coupling agent include: a silane coupling agent having a methacryloyl group in a molecule, and a silane coupling agent having a vinyl group in a molecule.

The resin composition used in the present embodiment can be used in the form of a varnish. For example, in the case of producing a prepreg, the prepreg can be used by being prepared into a varnish for the purpose of penetrating into a base material (fibrous base material) for forming the prepreg. That is, the resin composition can be used in a form prepared in a varnish form (resin varnish). In the resin composition used in the present embodiment, the polyphenylene ether copolymer, the thermosetting curing agent, and the thermoplastic elastomer are dissolved in the resin varnish. Such a varnish-like composition (resin varnish) can be prepared, for example, as follows.

First, each component soluble in an organic solvent is put into the organic solvent and dissolved. At this time, heating may be performed as necessary. Then, a component which is insoluble in the organic solvent and used as needed is added, and the mixture is dispersed in a predetermined dispersion state by using a ball mill, a bead mill, a planetary mixer, a roll mill, or the like, to prepare a varnish-like composition. The organic solvent used herein is not particularly limited as long as it is an organic solvent that can dissolve the polyphenylene ether copolymer, the thermosetting curing agent, and the thermoplastic elastomer and does not inhibit the curing reaction. Specific examples thereof include toluene and Methyl Ethyl Ketone (MEK).

Further, as described above, the insulating layer may contain not only the cured product of the resin composition but also a fibrous substrate. Examples of the fibrous substrate include the same fibrous substrates as those contained in the prepregs described later.

By using the resin composition, not only the metal-clad laminate but also a prepreg, a resin-coated metal foil, and a wiring board can be obtained as described below. In this case, as the resin composition, a varnish-like composition as described above can be used.

The prepreg includes: the aforementioned resin composition or a semi-cured product of the aforementioned resin composition; and a fibrous substrate. Examples of the prepreg include those in which a fibrous substrate is present in the semi-cured product. Namely, the prepreg comprises: the aforementioned resin composition or a semi-cured product of the aforementioned resin composition; and a fibrous substrate present in the resin composition or the semi-cured product of the resin composition.

In the present embodiment, the semi-cured product is a product obtained by curing the resin composition to such an extent that the resin composition can be further cured. That is, the semi-cured product is a product in a state in which the resin composition is semi-cured (B-stage). For example, if the resin composition is heated, the viscosity is initially gradually decreased, and then curing is started, and the viscosity is gradually increased. In this case, the semi-curing may be performed in a period from the start of viscosity increase to the time before complete curing.

The prepreg may be a prepreg provided with a semi-cured product of the resin composition as described above, or may be a prepreg provided with the uncured resin composition itself. That is, the prepreg may be a prepreg including a semi-cured product of the resin composition (the resin composition in the B stage) and a fibrous substrate, or may be a prepreg including the resin composition before curing (the resin composition in the a stage) and a fibrous substrate.

The method for producing the prepreg is not particularly limited as long as the prepreg can be produced. Examples thereof include: a method of impregnating a fibrous substrate with a resin composition (for example, a resin composition prepared in a varnish form). That is, the prepreg is obtained by impregnating a fibrous substrate with the resin composition. The method of impregnation is not particularly limited as long as the resin composition can be impregnated into the fibrous substrate. For example, the method is not limited to dipping, and a method using a roll, die coating (die coating), bar coating (bar coating), or spraying may be mentioned. In addition, as a method for producing a prepreg, a fibrous substrate impregnated with the resin composition may be dried or heated after the impregnation. That is, examples of the method for producing the prepreg include: a method of impregnating a fibrous substrate with a varnish-like resin composition and drying the impregnated fibrous substrate; a method of impregnating a fibrous substrate with a resin composition prepared in a varnish form and then heating the impregnated fibrous substrate; and a method in which the resin composition prepared in the form of varnish is impregnated into a fibrous substrate, dried, and then heated.

Specific examples of the fibrous base material used for producing the prepreg include glass cloth, aramid cloth, polyester cloth, glass nonwoven cloth, aramid nonwoven cloth, polyester nonwoven cloth, pulp paper, and cotton linter paper. In addition, if a glass cloth is used, a laminate excellent in mechanical strength can be obtained, and a glass cloth subjected to a flattening treatment is particularly preferable. Specifically, the flattening process may be performed by compressing the yarn into a flat shape by continuously pressing the glass cloth with a press roll at an appropriate pressure. The thickness of the fibrous substrate usually used is, for example, 0.04 to 0.3 mm.

The resin composition is impregnated into the fibrous substrate by impregnation, coating, or the like. This impregnation may be repeated as many times as necessary. In addition, in this case, the composition and the amount of impregnation may be adjusted to the final desired composition by repeatedly impregnating with a plurality of resin compositions having different compositions or concentrations.

The fibrous substrate impregnated with the resin composition is subjected to a desired heating condition (for example, heating at 80 to 180 ℃ C. for 1 to 10 minutes), whereby a prepreg before curing (A stage) or in a semi-cured state (B stage) can be obtained.

The prepreg can produce a metal foil-clad laminate, a wiring board, or the like, which has a reduced loss during signal transmission, has a high adhesion between the metal foil and the insulating layer, and is sufficiently suppressed in the decrease in adhesion between the metal foil and the insulating layer due to heating and moisture absorption.

The method for producing the metal-clad laminate according to the present embodiment is not particularly limited as long as the metal-clad laminate can be produced. As the method for producing the metal-clad laminate, for example, a metal-clad laminate can be obtained in the same manner as a method for producing a normal metal-clad laminate except that the resin composition is used. Examples of the method include a method using the prepreg using the resin composition. Examples of the method for producing a metal foil-clad laminate using a prepreg include: a method of laminating and integrating one prepreg or a plurality of prepregs on each other, further laminating a metal foil such as a copper foil on both upper and lower surfaces or one surface of the prepregs, and heating and pressing the prepregs. That is, the method for producing the metal-clad laminate includes: a step of obtaining the resin composition; a step of impregnating the resin composition into a fibrous substrate to obtain a prepreg; and a step of laminating a metal foil on the prepreg and heating and pressing the prepreg to obtain a metal foil-clad laminate including "an insulating layer containing a cured product of the resin composition" and "a metal foil present in contact with at least one surface of the insulating layer". By this method, a double-sided metal-foil-clad laminate or a single-sided metal-foil-clad laminate can be produced. That is, the metal-clad laminate according to the present embodiment includes: and a metal foil-clad laminate obtained by laminating a metal foil to the prepreg and performing heat and pressure molding. The heating and pressurizing conditions may be appropriately set according to the thickness of the laminate to be produced, the type of the resin composition contained in the prepreg, and the like. For example, the temperature may be set to 170 to 210 ℃, the pressure may be set to 2.5 to 4MPa, and the time may be set to 60 to 150 minutes. Further, the metal foil-clad laminate may be manufactured without using a prepreg. Examples thereof include: a method in which a varnish-like resin composition or the like is applied to a metal foil, a layer containing a curable composition is formed on the metal foil, and then heating and pressing are performed.

A resin-coated metal foil according to another embodiment of the present invention includes: an insulating adhesive layer and a metal foil present in contact with one surface of the insulating adhesive layer. As shown in fig. 2, the resin-attached metal foil 21 includes an insulating adhesive layer 22 and a metal foil 13 disposed so as to be in contact with one surface thereof. Fig. 2 is a cross-sectional view showing the structure of the resin-attached metal foil 21 according to the present embodiment.

The insulating adhesive layer 22 contains the resin composition (the resin composition in the a stage) or a semi-cured product of the resin composition (the resin composition in the B stage) as described above. The insulating adhesive layer may contain the resin composition or a semi-cured product of the resin composition, and may contain a fibrous substrate or may not contain a fibrous substrate. As the fibrous substrate, the same one as that of the prepreg can be used. The insulating adhesive layer is cured to become an insulating layer, for example, an insulating layer of a wiring board.

The metal foil 13 is the same as the metal foil provided in the metal-clad laminate. Specifically, the metal foil 13 includes a metal base 14 and a barrier layer 15, and the barrier layer 15 is provided on at least a contact surface 16 side of the metal base 14 with the insulating adhesive layer 22. As shown in fig. 2, the metal foil 13 includes a metal base 14 and a barrier layer 15, and the barrier layer 15 is provided on the side of the metal base 14 that is in contact with the insulating adhesive layer 22 on the contact surface 16 side. The metal foil may be provided with the barrier layer on both sides of the metal base material. The surface roughness of the contact surface 16 is 2 μm or less in terms of ten-point average roughness Rz.

The method for producing the resin-coated metal foil according to the present embodiment is not particularly limited as long as the resin-coated metal foil can be produced. The resin-coated metal foil can be produced by the same method as that for producing a usual resin-coated metal foil except that the resin composition is used. For example, a method of applying the resin composition (for example, a resin composition prepared in a varnish state) to the metal foil may be mentioned. That is, the resin-coated metal foil according to the embodiment of the present invention includes a member obtained by applying the resin composition to a metal foil. The coating method is not particularly limited as long as the resin composition can be applied to the metal foil. Examples thereof include a method using a roll, die coating, bar coating, and spraying. In addition, as a method for producing the metal foil with resin, the metal foil coated with the resin composition may be dried or heated after the coating. That is, examples of the method for producing the resin-coated metal foil include: a method of coating a resin composition prepared in a varnish form on a metal foil and then drying the coated metal foil; a method in which a resin composition prepared in a varnish form is applied to a metal foil and then heated; and a method in which the resin composition prepared in a varnish form is applied to a metal foil, dried, and then heated. The metal foil coated with the resin composition is heated under a desired heating condition (for example, at 80 to 180 ℃ C. for 1 to 10 minutes), whereby a resin-bearing metal foil can be obtained before curing (A stage) or in a semi-cured state (B stage).

The resin-coated metal foil as described above is a resin-coated metal foil which is reduced in loss during signal transmission, has high adhesion to the insulating layer obtained by curing the insulating adhesive layer, and is sufficiently suppressed in decrease in adhesion between the metal foil and the insulating layer due to heating and moisture absorption, as in the metal-clad laminate.

In addition, a wiring board according to another embodiment of the present invention includes: an insulating layer, and a wiring which is present in contact with at least one surface of the insulating layer. That is, the wiring board has wiring on the surface of the insulating layer. As shown in fig. 3, the wiring board 31 includes an insulating layer 12 and wirings 17 arranged so as to be in contact with both surfaces thereof. Further, the wiring board may be provided such that the wiring is in contact with only one surface of the insulating layer. Fig. 3 is a cross-sectional view showing the structure of the wiring board 31 according to the present embodiment.

The insulating layer 12 may be the same as that of the metal-clad laminate.

As shown in fig. 3, the wiring 17 includes a metal base 18 and a barrier layer 19, and the barrier layer 19 is provided on at least a contact surface 20 side of the metal base 18 with the insulating layer 12. Examples of the wiring 17 include a wiring formed by removing a part of the metal foil-clad laminate. Examples of the wiring include wirings formed by subtractive method, additive method, semi-additive method, Chemical Mechanical Polishing (CMP), and a method using grooves, ink jet, a squeegee, transfer, or the like. That is, the wiring 17 may be a wiring derived from a metal foil provided in the metal foil-clad laminate. Specifically, the wiring 17 includes a metal base 18 and a barrier layer 19, and the barrier layer 19 is provided on at least a contact surface 20 side of the metal base 18 with the insulating layer 12. As shown in fig. 3, the wiring 17 includes a metal base 18 and a barrier layer 19, and the barrier layer 19 is provided on the side of the metal base 18 that is in contact with the insulating layer 12 at a contact surface 20. The wiring may be provided with the barrier layer on both surfaces of the metal base material. The surface roughness of the contact surface 20 is 2 μm or less in terms of ten-point average roughness Rz.

The method for manufacturing a wiring board according to the present embodiment is not particularly limited as long as the wiring board can be manufactured using the metal foil-clad laminate or the metal foil with resin. Examples of the method for producing the wiring board include a method using a general metal foil-clad laminate. Examples of a method for producing a wiring board using a metal-clad laminate include a method in which a metal foil on the surface of a metal-clad laminate is subjected to etching or the like to form a circuit. By this method, a wiring board having a conductor pattern as a circuit on the surface of the metal foil-clad laminate can be obtained. That is, the wiring board according to the present embodiment is a wiring board in which a circuit is formed by partially removing the metal foil on the surface of the metal foil-clad laminate. Examples of the method for manufacturing the wiring board include a method including the steps of: a step of obtaining the resin composition; a step of impregnating the resin composition into a fibrous substrate to obtain a prepreg; a step of laminating a metal foil on the prepreg and heating and pressing the laminate to obtain a metal foil-clad laminate including an insulating layer containing a cured product of the resin composition and a metal foil present in contact with at least one surface of the insulating layer; and forming a wiring in contact with at least one surface of the insulating layer by partially removing the metal foil of the metal foil-clad laminate.

The wiring board has reduced loss during signal transmission, high adhesion between the wiring and the insulating layer, and sufficiently suppressed decrease in adhesion between the wiring and the insulating layer due to heating and moisture absorption.

The present specification discloses the techniques of the various embodiments as described above, and the main techniques thereof are summarized as follows.

One aspect of the present invention relates to a metal-clad laminate comprising: an insulating layer; and a metal foil present in contact with at least one surface of the insulating layer, wherein the insulating layer contains a cured product of a resin composition containing: a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the following formula (1) or formula (2) per molecule at the molecular end, a thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at the molecular end, and a thermoplastic elastomer, wherein the metal foil comprises: and a barrier layer that is provided on at least a contact surface side of the metal base material with the insulating layer and that contains cobalt, wherein a surface roughness of the contact surface is 2 [ mu ] m or less in terms of a ten-point average roughness Rz.

In the formula (1), R₁R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms₂Represents an alkylene group having 1 to 10 carbon atoms.

In the formula (2), R₃Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

According to this configuration, there can be provided: the metal foil-clad laminate is reduced in loss during signal transmission, has high adhesion between the metal foil and the insulating layer, and is sufficiently suppressed in the decrease in adhesion between the metal foil and the insulating layer due to heating and moisture absorption.

In the metal-clad laminate, it is preferable that: the thermoplastic elastomer is a styrene thermoplastic elastomer.

According to this configuration, there can be provided: the metal foil-clad laminate is reduced in loss during signal transmission, has high adhesion between the metal foil and the insulating layer, and is further inhibited from lowering in adhesion between the metal foil and the insulating layer due to heating and moisture absorption.

In the metal-clad laminate, it is preferable that: the styrene-based thermoplastic elastomer is a thermoplastic elastomer obtained by hydrogenating a part or all of double bonds of at least one copolymer selected from a methylstyrene (ethylene/butylene) methylstyrene copolymer, a styrene (ethylene/propylene) styrene copolymer, a styrene (ethylene/butylene) styrene copolymer, a styrene (butadiene/isoprene) styrene copolymer, and a styrene isoprene styrene copolymer.

According to this configuration, there can be provided: the metal foil-clad laminate is reduced in loss during signal transmission, has high adhesion between the metal foil and the insulating layer, and is further inhibited from lowering in adhesion between the metal foil and the insulating layer due to heating and moisture absorption.

In the metal-clad laminate, it is preferable that: the styrene-based thermoplastic elastomer is at least one selected from the group consisting of a hydrogenated methylstyrene (ethylene/butylene) methylstyrene copolymer, a hydrogenated methylstyrene (ethylene-ethylene/propylene) methylstyrene copolymer, a hydrogenated styrene isoprene styrene copolymer, a hydrogenated styrene (ethylene/butylene) styrene copolymer, a hydrogenated styrene (ethylene/propylene) styrene copolymer, and a hydrogenated styrene (ethylene-ethylene/propylene) styrene copolymer.

According to this configuration, there can be provided: the metal foil-clad laminate is reduced in loss during signal transmission, has high adhesion between the metal foil and the insulating layer, and is further inhibited from lowering in adhesion between the metal foil and the insulating layer due to heating and moisture absorption.

In the metal-clad laminate, it is preferable that: the ratio of the sum of the content of the polyphenylene ether copolymer and the content of the thermosetting curing agent to the content of the thermoplastic elastomer is 50: 50 to 90: 10 in terms of mass ratio.

According to this configuration, there can be provided: the metal foil-clad laminate is reduced in loss during signal transmission, has high adhesion between the metal foil and the insulating layer, and is further inhibited from lowering in adhesion between the metal foil and the insulating layer due to heating and moisture absorption.

In the metal-clad laminate, it is preferable that: the resin composition further contains a silane coupling agent having at least one selected from the group consisting of a vinyl group, a styryl group, a methacryloyl group and an acryloyl group in a molecule.

According to this configuration, there can be provided: the metal foil-clad laminate is reduced in loss during signal transmission, has a higher adhesive strength between the metal foil and the insulating layer, and is sufficiently suppressed in the decrease in adhesive strength between the metal foil and the insulating layer due to heating and moisture absorption.

Further, another aspect of the present invention relates to a metal foil with resin, comprising: an insulating adhesive layer; and a metal foil present in contact with at least one surface of the insulating adhesive layer, wherein the insulating adhesive layer contains a resin composition or a semi-cured product of the resin composition, and the resin composition contains: a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the formula (1) or the formula (2) per molecule at a molecular end, a thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at a molecular end, and a thermoplastic elastomer, the metal foil comprising: and a barrier layer which is provided on at least the contact surface side of the metal base material with the insulating adhesive layer and contains cobalt, wherein the surface roughness of the contact surface is 2 [ mu ] m or less in terms of ten-point average roughness Rz.

According to this configuration, there can be provided: the resin-attached metal foil has a reduced loss during signal transmission, a high adhesive force between the metal foil and an insulating layer obtained by curing the insulating adhesive layer, and a sufficiently suppressed decrease in adhesive force between the metal foil and the insulating layer due to heating and moisture absorption.

Further, another aspect of the present invention relates to a wiring board, including: an insulating layer; and a wiring which is present in contact with at least one surface of the insulating layer, wherein the insulating layer contains a cured product of a resin composition containing: a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12dl/g as measured in methylene chloride at 25 ℃ and having an average of 1.5 to 3 groups represented by the formula (1) or the formula (2) per molecule at a molecular end, a thermosetting curing agent having 2 or more carbon-carbon unsaturated double bonds at a molecular end, and a thermoplastic elastomer, the metal foil comprising: and a barrier layer that is provided on at least a contact surface side of the metal base material with the insulating layer and that contains cobalt, wherein a surface roughness of the contact surface is 2 [ mu ] m or less in terms of a ten-point average roughness Rz.

According to this configuration, there can be provided: the wiring board has reduced loss during signal transmission, high adhesion between the wiring and the insulating layer, and sufficiently suppressed decrease in adhesion between the wiring and the insulating layer due to heating and moisture absorption.

According to the present invention, there can be provided: a metal foil-clad laminate, a resin-containing metal foil, and a wiring board, in which loss during signal transmission is reduced, the adhesion between the metal foil and the insulating layer is high, and the reduction in adhesion between the metal foil and the insulating layer due to heating and moisture absorption is sufficiently suppressed.

The present invention will be further specifically described below with reference to examples, but the scope of the present invention is not limited thereto.