Low dielectric resin composition, adhesion imparting agent, low dielectric adhesive molding material, low dielectric adhesive molded article, low dielectric adhesive, laminate, and method for producing low dielectric resin composition

Abstract

To provide a low dielectric resin composition excellent in low dielectric property, an adhesion imparting agent, a low dielectric adhesive molding material, a low dielectric adhesive molded article, a low dielectric adhesive, a laminate and a method for producing a low dielectric resin composition.SOLUTION: A low dielectric resin composition contains an essential resin component which is composed of a styrenic elastomer, a resin containing an aromatic ring, and a reaction product of the styrenic elastomer and the resin containing the aromatic ring. In molecular weight distribution of gel permeation chromatography of the essential resin component, a ratio (M2 / M1) of a molecular weight (M2) in terms of polystyrene at a position which is on a side closer to the high molecular weight side than a peak top and has 10% peak intensity of peak strength of the peak top to a molecular weight (M1) in terms of polystyrene of a peak top of a peak attributed to the styrenic elastomer is 1.7 or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a low-dielectric resin composition, an adhesion-imparting agent, a low-dielectric adhesive molding material, a low-dielectric adhesive molded article, a low-dielectric adhesive, a laminate, and a method for producing a low-dielectric resin composition.

Background Art

[0002] In recent years, from the viewpoint of coping with high frequencies, materials used in communication devices and electronic devices are required to have low dielectric properties.

[0003] As such a material, for example, a resin composition containing a styrene-based elastomer, a resin having a radically polymerizable unsaturated group, and a curing agent has been proposed (see, for example, Patent Document 1). In Patent Document 1, an insulating layer is produced by curing the resin composition.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, such materials are required to have more excellent low dielectric properties.

[0006] The present invention provides a low-dielectric resin composition, an adhesion-imparting agent, a low-dielectric adhesive molding material, a low-dielectric adhesive molded article, a low-dielectric adhesive, a laminate, and a method for producing a low-dielectric resin composition, which are excellent in low dielectric properties.

Means for Solving the Problems

[0007] The present invention [1] includes an essential resin component composed of a styrenic elastomer, a resin containing an aromatic ring, and a reaction product of the styrenic elastomer and the resin containing an aromatic ring. In the molecular weight distribution of gel permeation chromatography of the essential resin component, the ratio (M2 / M1) of the polystyrene-equivalent molecular weight (M2) at a position that is located on the higher molecular weight side than the peak top of the peak attributed to the styrenic elastomer and has a peak intensity of 10% of the peak intensity of the peak top to the polystyrene-equivalent molecular weight (M1) of the peak top is 1.7 or more, and it is a low dielectric resin composition.

[0008] The present invention [2] includes the low dielectric resin composition according to [1] above, in which the weight average molecular weight in terms of polystyrene of the resin containing an aromatic ring is 1,000 or more and 50,000 or less.

[0009] The present invention [3] includes the low dielectric resin composition according to [1] or [2] above, in which the resin containing an aromatic ring is a polymer of a polymerization component containing an aromatic ring-containing monomer, and the content ratio of the aromatic ring-containing monomer is 30% by mass or more based on the polymerization component.

[0010] The present invention [4] includes the low dielectric resin composition according to any one of [1] to [3] above, in which the styrenic elastomer contains a structural unit derived from styrene, and the content ratio of the structural unit derived from styrene is 20% by mass or more and 70% by mass or less based on the total amount of the styrenic elastomer.

[0011] The present invention [5] includes an adhesion promoter containing the low dielectric resin composition according to any one of [1] to [4] above.

[0012] The present invention [6] includes a thermosetting resin and the adhesion promoter described in [5] above, and the thermosetting resin includes at least one selected from the group consisting of an epoxy resin, a polyphenylene ether resin, a fluororesin, a polyimide resin, a phenol resin, a melamine resin, a polyolefin resin having an unsaturated double bond, and a liquid crystal polymer, and includes a low dielectric adhesion molding material.

[0013] The present invention [7] includes a low dielectric adhesion molded article including a cured product of the low dielectric adhesion molding material described in [6] above.

[0014] The present invention [8] includes a laminate including an insulating layer including the low dielectric adhesion molded article described in [7] above, and a conductor layer disposed on at least one surface of the insulating layer.

[0015] The present invention [9] includes a low dielectric adhesive including the low dielectric resin composition according to any one of [1] to [4] above.

[0016] The present invention

[10] includes an insulating layer, a conductor layer disposed opposite to the insulating layer, and an adhesive layer disposed between the insulating layer and the conductor layer and bonding the insulating layer and the conductor layer, and the adhesive layer includes the low dielectric adhesive described in [9] above, and includes a laminate.

[0017] The present invention

[11] includes a first conductor layer, a second conductor layer disposed opposite to the first conductor layer, and an adhesive layer disposed between the first conductor layer and the second conductor layer and bonding the first conductor layer and the second conductor layer, and the adhesive layer includes the low dielectric adhesive described in [9] above, and includes a laminate.

[0018] The present invention

[12] is a method for manufacturing the low dielectric adhesion molded article according to any one of [1] to [4] above, and includes a method for manufacturing a low dielectric resin composition in which a styrene-based elastomer, a resin containing an aromatic ring, and a peroxide are mixed to react the styrene-based elastomer and the resin containing an aromatic ring.

Advantages of the Invention

[0019] The low-dielectric resin composition of the present invention contains an essential resin component composed of a styrene-based elastomer, a resin containing an aromatic ring, and a reaction product of the styrene-based elastomer and the resin containing an aromatic ring. In the molecular weight distribution of gel permeation chromatography of the essential resin component, the ratio (M2 / M1) of the polystyrene-equivalent molecular weight (M2) at a position that is located on the higher molecular weight side than the peak top of the peak attributed to the styrene-based elastomer and has a peak intensity of 10% of the peak intensity of the peak top to the polystyrene-equivalent molecular weight (M1) of the peak top is 1.7 or more. Therefore, it is excellent in low dielectric properties.

[0020] The adhesion promoter of the present invention contains the low-dielectric resin composition of the present invention. Therefore, it is excellent in low dielectric properties.

[0021] The low-dielectric adhesive molding material of the present invention contains the adhesion promoter of the present invention. Therefore, it is excellent in low dielectric properties.

[0022] The low-dielectric adhesive molded article of the present invention contains a cured product of the low-dielectric adhesive molding material of the present invention. Therefore, it is excellent in low dielectric properties.

[0023] The low-dielectric adhesive of the present invention contains the low-dielectric resin composition of the present invention. Therefore, it is excellent in low dielectric properties.

[0024] The laminate of the present invention includes an insulating layer containing the low-dielectric adhesive molded article of the present invention or an adhesive layer containing the low-dielectric adhesive of the present invention. Therefore, it is excellent in low dielectric properties.

[0025] The method for producing the low-dielectric resin composition of the present invention is to mix a styrene-based elastomer, a resin containing an aromatic ring, and a peroxide to react the styrene-based elastomer and the resin containing an aromatic ring. Therefore, a low-dielectric resin composition excellent in low dielectric properties can be produced.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0027] 1. Low dielectric resin composition The low dielectric resin composition contains an essential resin component.

[0028] The essential resin component consists of a styrenic elastomer, a resin containing an aromatic ring, and a reaction product of the styrenic elastomer and the resin containing an aromatic ring.

[0029] <Styrenic elastomer> The styrenic elastomer is, for example, a copolymer of styrene and a chain olefin.

[0030] Examples of the chain olefin include chain olefins having 2 to 8 carbon atoms. Chain olefins having 2 to 8 carbon atoms include, for example, ethylene, propylene, butylene (butene), pentene, hexene, octene, and 3-methyl-1-pentene. Preferred chain olefins include ethylene, propylene, and butylene.

[0031] The chain olefins can be used alone or in combination of two or more. Preferred combinations of chain olefins include a combination of ethylene and propylene, and a combination of ethylene and butylene.

[0032] The styrenic elastomer is produced by a known method. The styrenic elastomer is produced, for example, by polymerizing styrene and a chain olefin in the presence of a known initiator (for example, an alkyl lithium compound). The polymerization conditions are appropriately set according to the purpose and application.

[0033] The styrenic elastomer contains a structural unit derived from styrene and a structural unit derived from a chain olefin. The styrenic elastomer preferably consists of a structural unit derived from styrene and a structural unit derived from a chain olefin.

[0034] The content ratio of the structural unit derived from styrene is, for example, 20% by mass to 70% by mass, preferably 25% by mass to 50% by mass, more preferably 28% by mass to 40% by mass, based on the total amount of the styrenic elastomer.

[0035] Specifically, from the perspective of solution stability, the content ratio of the structural unit derived from styrene is, for example, 20% by mass or more, preferably 25% by mass or more, more preferably 28% by mass or more, based on the total amount of the styrene-based elastomer. From the perspective of low dielectric properties, it is, for example, 70% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less.

[0036] In addition, the content ratio of the constitutional unit derived from the chain olefin is, for example, 30% to 80% by mass, preferably 50% to 75% by mass, more preferably 60% to 72% by mass, based on the total amount of the styrene-based elastomer.

[0037] Specifically, the content ratio of the constitutional unit derived from the chain olefin is 30% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, based on the total amount of the styrene-based elastomer, and, for example, 80% by mass or less, preferably 75% by mass or less, more preferably 72% by mass or less.

[0038] Note that the content ratio of the structural unit derived from the above-mentioned styrene and the content ratio of the structural unit derived from the chain olefin are calculated based on the compounding formulation of the polymerization raw materials of the styrene-based elastomer. Specifically, the content ratio of the structural unit derived from styrene is calculated as the ratio of styrene to the total amount of the polymerization raw materials (styrene and chain olefin). In addition, the content ratio of the structural unit derived from the chain olefin is calculated as the ratio of the chain olefin to the total amount of the polymerization raw materials (styrene and chain olefin).

[0039] Examples of such styrenic elastomers include, for example, styrene-ethylene-propylene copolymer (SEP), styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-butadiene-styrene copolymer (SBS), styrene-ethylene-butylene-styrene copolymer (SEBS), and styrene-isobutylene-styrene copolymer (SIBS). These copolymers are random copolymers or block copolymers.

[0040] From the perspective of low dielectric properties, the styrenic elastomer is preferably at least one selected from the group consisting of styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), and styrene-ethylene-butylene-styrene copolymer (SEBS). From the perspective of low dielectric properties, more preferably, the styrenic elastomer is styrene-ethylene-butylene-styrene copolymer (SEBS).

[0041] Commercially available products can also be used as the styrenic elastomer.

[0042] Examples of commercially available products of the styrenic elastomer include, for example, the product name SEPTON series (manufactured by Kuraray) and the product name Kraton series (manufactured by Kraton Polymer Japan).

[0043] The styrenic elastomer can be used alone or in combination of two or more.

[0044] The weight average molecular weight of the styrenic elastomer is more than 50,000, preferably 55,000 or more, more preferably 60,000 or more, still more preferably 70,000 or more, and from the perspective of solution stability, for example, 500,000 or less, preferably 300,000 or less, more preferably 100,000 or less, still more preferably 60,000 or less.

[0045] The dispersity (weight-average molecular weight / number-average molecular weight) of the molecular weight distribution of the styrenic elastomer is, for example, 2.0 or less, preferably 1.6 or less, and, for example, 1.0 or more, preferably 1.1 or more.

[0046] Incidentally, the weight-average molecular weight and the dispersity of the styrenic elastomer are measured as the molecular weight in terms of standard polystyrene by gel permeation chromatography (the same shall apply hereinafter).

[0047] The content ratio of the styrenic elastomer is, for example, 50% by mass to 95% by mass, preferably 70% by mass to 90% by mass, with respect to the low-dielectric resin composition.

[0048] <Resin containing an aromatic ring> The resin containing an aromatic ring is a polymer of a polymerization component containing an aromatic-ring-containing monomer. That is, the resin containing an aromatic ring has an aromatic ring derived from the aromatic-ring-containing monomer.

[0049] Examples of the aromatic-ring-containing monomer include styrene, α-methylstyrene (2-phenylpropylene), 2-phenylbutene, 3-phenylpropylene, divinylbenzene, 1-vinylnaphthalene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, 3-methyl-5-ethylstyrene, p-tert-butylstyrene, p-sec-butylstyrene, p-chlorostyrene, p-vinylbenzoic acid, p-vinylbenzoic acid esters, vinyl benzoate, isopropenyltoluene, and indene. Preferred examples of the aromatic-ring-containing vinyl monomer include styrene, isopropenyltoluene, and indene.

[0050] The aromatic-ring-containing monomers can be used alone or in combination of two or more.

[0051] The content ratio of the aromatic ring-containing monomer is, for example, 30% by mass to 100% by mass, preferably 33% by mass to 100% by mass, more preferably 35% by mass to 100% by mass, still more preferably 38% by mass to 100% by mass, based on the polymerization components.

[0052] Specifically, from the viewpoint of solution stability, the content ratio of the aromatic ring-containing monomer is, for example, 30% by mass or more, preferably 33% by mass or more, more preferably 35% by mass or more, still more preferably 38% by mass or more, based on the polymerization components.

[0053] The polymerization components can include a copolymerizable monomer copolymerizable with the aromatic ring-containing vinyl monomer.

[0054] Examples of the copolymerizable monomer include (meth)acrylic acid alkyl esters (excluding vinyl monomers having an alicyclic structure; the same applies hereinafter), vinyl monomers having an alicyclic structure, glycidyl group-containing vinyl monomers, and unsaturated aliphatic hydrocarbons. Note that (meth)acrylic represents acrylic and / or methacrylic.

[0055] Examples of the (meth)acrylic acid alkyl ester include alkyl (meth)acrylates having an alkyl moiety with 1 to 12 carbon atoms. Examples of the alkyl (meth)acrylate having an alkyl moiety with 1 to 12 carbon atoms include alkyl (meth)acrylates having an alkyl moiety with 1 to 4 carbon atoms and alkyl (meth)acrylates having an alkyl moiety with 5 to 12 carbon atoms.

[0056] Examples of the alkyl (meth)acrylate having an alkyl moiety with 1 to 4 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and t-butyl (meth)acrylate.

[0057] Examples of the alkyl (meth)acrylate having an alkyl moiety with 5 to 12 carbon atoms include n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, and octadecyl (meth)acrylate.

[0058] Examples of the alkyl (meth)acrylate preferably include an alkyl (meth)acrylate having an alkyl moiety with 1 to 4 carbon atoms. More preferably, n-butyl (meth)acrylate can be mentioned as the alkyl (meth)acrylate. Even more preferably, n-butyl acrylate can be mentioned as the alkyl (meth)acrylate.

[0059] The content ratio of the alkyl (meth)acrylate is, for example, 0% by mass to 30% by mass, preferably 0% by mass to 20% by mass, and more preferably 0% by mass to 10% by mass with respect to the polymerization components.

[0060] Examples of the vinyl monomer having an alicyclic structure include a monocyclic alicyclic structure-containing vinyl monomer, a bicyclic alicyclic structure-containing vinyl monomer, and a polycyclic alicyclic structure-containing vinyl monomer.

[0061] The monocyclic alicyclic structure-containing vinyl monomer contains one alicyclic structure. Examples of the monocyclic alicyclic structure-containing vinyl monomer include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and cycloheptyl (meth)acrylate.

[0062] The bicyclic alicyclic structure-containing vinyl monomer contains two alicyclic structures. Examples of the bicyclic alicyclic structure-containing vinyl monomer include norbornyl (meth)acrylate, decahydronaphthyl (meth)acrylate, bicycloundecyl (meth)acrylate, and isobornyl (meth)acrylate.

[0063] The polycyclic alicyclic structure-containing vinyl monomer contains three or more alicyclic structures. Examples of the polycyclic alicyclic structure-containing vinyl monomer include tricyclo[5.2.1.0 2,6 ]Decyl (meth)acrylate, Tricyclo[5.2.1.0 2,6 ]dec-3-yl(meth)acrylate, and 2-adamantyl(meth)acrylate.

[0064] As the vinyl monomer having an alicyclic structure, preferably, a bicyclic alicyclic structure-containing vinyl monomer is used. As the vinyl monomer having an alicyclic structure, more preferably, norbornyl (meth)acrylate is used. As the vinyl monomer having an alicyclic structure, more preferably, norbornyl methacrylate is used.

[0065] The content of the vinyl monomer having an alicyclic structure relative to the polymerization components is, for example, 0% by mass to 70% by mass, preferably 0% by mass to 67% by mass, more preferably 0% by mass to 65% by mass, and still more preferably 0% by mass to 62% by mass.

[0066] Examples of the glycidyl group-containing vinyl monomer include glycidyl (meth)acrylate. Examples of the glycidyl group-containing vinyl monomer include preferably glycidyl methacrylate.

[0067] The content of the glycidyl group-containing vinyl monomer is, for example, 0% by mass to 10% by mass, or preferably 0% by mass to 5% by mass, relative to the polymerization components.

[0068] Unsaturated aliphatic hydrocarbons include, for example, C4 and C5 fractions.

[0069] The C4 fraction is obtained by refining and / or cracking petroleum. The C4 fraction is a fraction having a boiling point range of −15° C. or more and 45° C. or less under normal pressure, and includes, for example, unsaturated aliphatic hydrocarbons having 4 carbon atoms and no conjugated double bonds, and unsaturated aliphatic hydrocarbons having 4 carbon atoms and containing conjugated double bonds.

[0070] Examples of unsaturated aliphatic hydrocarbons having 4 carbon atoms and not containing a conjugated double bond include 1-butene, isobutene, and 2-butene.

[0071] Examples of unsaturated aliphatic hydrocarbons having 4 carbon atoms and containing a conjugated double bond include 1,3-butadiene.

[0072] The C5 fraction is obtained by refining and / or cracking of petroleum. The C5 fraction is a fraction having a boiling point range of usually -15°C or higher and 45°C or lower under normal pressure, and includes, for example, unsaturated aliphatic hydrocarbons having 5 carbon atoms and not containing a conjugated double bond, and unsaturated aliphatic hydrocarbons having 5 carbon atoms and containing a conjugated double bond.

[0073] Examples of unsaturated aliphatic hydrocarbons having 5 carbon atoms and not containing a conjugated double bond include 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, and 2-pentene.

[0074] Examples of unsaturated aliphatic hydrocarbons having 5 carbon atoms and containing a conjugated double bond include isoprene, 1,3-pentadiene, and cyclopentadiene.

[0075] The content ratio of the unsaturated aliphatic hydrocarbon is, for example, 0 mass% to 20 mass%, preferably 5 mass% to 15 mass%, based on the polymerization component.

[0076] The copolymerizable monomer can be used alone or in combination of two or more.

[0077] Examples of such resins containing an aromatic ring include copolymers of an aromatic ring-containing monomer and a vinyl monomer having an alicyclic structure (preferably a copolymer of styrene and norbornyl methacrylate), copolymers of an aromatic ring-containing monomer, an alkyl (meth)acrylate, and an unsaturated aliphatic hydrocarbon (preferably a copolymer of styrene, n-butyl acrylate, and glycidyl methacrylate), copolymers of an aromatic ring-containing monomer and an unsaturated aliphatic hydrocarbon (preferably a copolymer of isopropenyltoluene and a C5 fraction), copolymers of an aromatic ring-containing monomer and an alkyl (meth)acrylate (preferably a copolymer of styrene and n-butyl acrylate), and polymers of an aromatic ring-containing monomer (preferably a homopolymer of styrene or a copolymer of styrene and indene). That is, the resin containing an aromatic ring is preferably at least one selected from the group consisting of copolymers of an aromatic ring-containing monomer and a vinyl monomer having an alicyclic structure, copolymers of an aromatic ring-containing monomer, an alkyl (meth)acrylate, and an unsaturated aliphatic hydrocarbon, copolymers of an aromatic ring-containing monomer and an unsaturated aliphatic hydrocarbon, copolymers of an aromatic ring-containing monomer and an alkyl (meth)acrylate, and polymers of an aromatic ring-containing monomer. From the viewpoint of low dielectric constant, more preferably, the resin containing an aromatic ring is a copolymer of an aromatic ring-containing monomer and a vinyl monomer having an alicyclic structure.

[0078] The content ratio of the copolymerizable monomer is, for example, 0% by mass to 70% by mass, preferably 0% by mass to 67% by mass, more preferably 0% by mass to 65% by mass, and even more preferably 0% by mass to 62% by mass with respect to the polymerization components.

[0079] The resin containing an aromatic ring is obtained by polymerizing the polymerization components. The polymerization method of the polymerization components is not particularly limited, and a known polymerization method is adopted.

[0080] As the polymerization method of the polymerization components, preferably, the polymerization components are radically polymerized in a solvent (e.g., xylene). In this method, for example, the polymerization components and a peroxide are blended in the solvent and polymerized in the solvent.

[0081] Examples of the peroxide include 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, di-t-butyl peroxide, t-butyl hydroperoxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxybenzoate, and lauroyl peroxide. As the peroxide, t-butyl peroxy-2-ethylhexanoate is more preferably mentioned.

[0082] The blending ratio of the peroxide is appropriately set according to the purpose and application.

[0083] The peroxide can be used alone or in combination of two or more.

[0084] As the polymerization conditions, the polymerization temperature is, for example, 60°C to 110°C, preferably 80°C to 100°C. The polymerization time is, for example, 0.5 hours to 6 hours, preferably 1 hour to 3 hours.

[0085] Thereby, the polymerization components are polymerized to produce a resin containing an aromatic ring.

[0086] The weight average molecular weight of the resin containing an aromatic ring is 50,000 or less, preferably 40,000 or less, more preferably 30,000 or less, still more preferably 10,000 or less, particularly preferably 5,000 or less, and also, for example, 1,000 or more, preferably 1,500 or more, more preferably 2,000 or more, still more preferably 2,500 or more.

[0087] If the weight average molecular weight of the resin containing an aromatic ring is below the above upper limit, the solution stability can be improved.

[0088] If the weight average molecular weight of the resin containing an aromatic ring is above the above lower limit, the low dielectric property can be improved.

[0089] The content ratio of the resin containing an aromatic ring is, for example, 5% by mass to 30% by mass, preferably 10% by mass to 20% by mass, based on the low dielectric constant resin composition.

[0090] <Distinction between styrenic elastomer and resin containing aromatic ring> The weight average molecular weight of the styrenic elastomer exceeds 50,000, while the weight average molecular weight of the resin containing an aromatic ring is 50,000 or less.

[0091] The ratio of the weight average molecular weight of the styrenic elastomer to the weight average molecular weight of the resin containing an aromatic ring exceeds 1.0, preferably is 10 or more, more preferably is 20 or more, and, for example, is 50 or less.

[0092] That is, the styrenic elastomer has a high molecular weight relative to the resin containing an aromatic ring. In other words, the resin containing an aromatic ring has a low molecular weight relative to the styrenic elastomer.

[0093] <Reaction product of styrenic elastomer and resin containing aromatic ring> The reaction product of the styrenic elastomer and the resin containing an aromatic ring is produced by reacting the styrenic elastomer and the resin containing an aromatic ring in the presence of a peroxide, although details will be described later.

[0094] The content ratio of the reaction product of the styrenic elastomer and the resin containing an aromatic ring is, for example, 0.5% by mass to 80% by mass, preferably 1% by mass to 50% by mass, based on the low dielectric constant resin composition.

[0095] The content ratio of the essential resin component is, for example, 80% by mass or more, preferably 90% by mass or more, more preferably 100% by mass, based on the low dielectric constant resin composition.

[0096] <Optional resin component> The low dielectric constant resin composition may also contain an optional resin component.

[0097] Examples of the optional resin component include olefin polymers.

[0098] Examples of the olefin polymer include polyethylene, polypropylene, polyisobutylene, poly-1-butene, poly-4-methylpentene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-butene copolymer, ethylene-4-methyl-1-pentene copolymer, and propylene-4-methyl-1-pentene copolymer.

[0099] The optional resin component can be used alone or in combination of two or more.

[0100] The content ratio of the optional resin component is, for example, 0% by mass to 20% by mass, preferably 0% by mass to 10% by mass, based on the low dielectric resin composition.

[0101] The low dielectric resin composition preferably does not contain an optional resin component and consists of an essential resin component.

[0102] <Additive> The low dielectric resin composition may contain an additive in an appropriate ratio if necessary. Examples of the additive include plasticizers, defoamers, leveling agents, fungicides, rust preventives, matting agents, flame retardants, thixotropic agents, tackifiers, thickeners, lubricants, antistatic agents, surfactants, reaction retardants, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, weather stabilizers, heat stabilizers, dyes, inorganic pigments, organic pigments, curing agents, crosslinking agents, silane coupling agents, tack preventives, inorganic particles, and organic particles.

[0103] The additives can be used alone or in combination of two or more.

[0104] <Method for producing low dielectric resin composition> In the method for producing a low dielectric resin composition, a styrene-based elastomer, a resin containing an aromatic ring, a peroxide, and, if necessary, an additive to be blended are mixed. Examples of the mixing method include a melt kneading method.

[0105] The blending ratio of the styrenic elastomer is, for example, 60 parts by mass to 90 parts by mass, preferably 70 parts by mass to 85 parts by mass, based on 100 parts by mass of the total amount of the styrenic elastomer and the resin containing an aromatic ring.

[0106] The blending ratio of the resin containing an aromatic ring is, for example, 10 parts by mass to 40 parts by mass, preferably 15 parts by mass to 30 parts by mass, based on 100 parts by mass of the total amount of the styrenic elastomer and the resin containing an aromatic ring.

[0107] The peroxide is the peroxide exemplified in the resin containing the aromatic ring, and preferably includes 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane).

[0108] The blending ratio of the peroxide is, for example, 0.1 parts by mass to 5.0 parts by mass, preferably 0.5 parts by mass to 1.0 parts by mass, based on 100 parts by mass of the total amount of the styrenic elastomer and the resin containing an aromatic ring.

[0109] And in the above mixing, the styrenic elastomer and the resin containing an aromatic ring are reacted.

[0110] Regarding the above reaction, as the styrenic elastomer, a styrene-ethylene-propylene-styrene copolymer (SEPS) and, as the resin containing an aromatic ring, a homopolymer of styrene (PS) are exemplified and will be detailed below.

[0111] In this reaction, first, the peroxide decomposes to generate radicals. Next, these radicals extract hydrogen from SEPS and PS, generating radicals on the hydrocarbon. And by these radicals, SEPS and PS react.

[0112] In addition, in the above reaction, it is presumed that the reaction between SEPS and the reaction between PS also proceed.

[0113] In the reaction, the reaction temperature is, for example, 150°C to 280°C, preferably 200°C to 240°C. The reaction time is, for example, 0.5 hour to 12 hours.

[0114] Thereafter, it is cooled, and if necessary, an optional resin component and, if necessary, an additive are blended. That is, the optional resin component is blended under the condition that it does not react with the styrene-based elastomer and the resin containing an aromatic ring. Thereby, a low dielectric resin composition is produced.

[0115] The low dielectric resin composition can also be diluted with a known organic solvent to obtain a diluted solution of the low dielectric resin composition. The solid content concentration of the diluted solution of the low dielectric resin composition is, for example, 10% by mass to 40% by mass, preferably 15% by mass to 30% by mass.

[0116] And in the low dielectric resin composition, in the molecular weight distribution of gel permeation chromatography with respect to the essential resin component, a predetermined peak has a predetermined relationship.

[0117] Although it will be described in detail in the examples described later, FIG. 9 shows the molecular weight distribution of gel permeation chromatography with respect to the essential resin component of Example 3.

[0118] In the molecular weight distribution, a peak A attributed to the styrene-based elastomer, a peak B attributed to the resin containing an aromatic ring, and a peak C attributed to the reaction product of the styrene-based elastomer and the resin containing an aromatic ring are observed.

[0119] In the low dielectric resin composition, in the molecular weight distribution of the gel permeation chromatography of the essential resin component, with respect to the polystyrene-reduced molecular weight (M1) of the peak top A' of peak A attributed to the styrene-based elastomer, a position D located on the higher molecular weight side than the peak top A' and having a peak intensity of 10% of the peak intensity of the peak top A' has a ratio (M2 / M1) of the polystyrene-reduced molecular weight (M2) of 1.7 or more, preferably 1.9 or more, more preferably 2.0 or more, still more preferably 2.5 or more, particularly preferably 3.0 or more, and also, for example, 9.0 or less, preferably 8.0 or less, more preferably 6.0 or less, still more preferably 5.0 or less, particularly preferably 4.0 or less.

[0120] If the above ratio is at least the above lower limit, the low dielectric property can be improved.

[0121] Specifically, the above ratio is an index of the content ratio of the reaction product of the styrene-based elastomer and the resin containing an aromatic ring in the low dielectric resin composition. When the above ratio increases, the content ratio of the reaction product of the styrene-based elastomer and the resin containing an aromatic ring in the low dielectric resin composition increases, and when the above ratio decreases, the content ratio of the reaction product of the styrene-based elastomer and the resin containing an aromatic ring in the low dielectric resin composition decreases.

[0122] Although it will be described in detail later, in Comparative Example 4 that does not contain the reaction product of the styrene-based elastomer and the resin containing an aromatic ring, since the above ratio is 1.5, if the above ratio is 1.7 or more, it can be seen that the low dielectric resin composition contains a predetermined amount of the reaction product of the styrene-based elastomer and the resin containing an aromatic ring.

[0123] And by the low dielectric resin composition containing a predetermined amount of the reaction product of the styrene-based elastomer and the resin containing an aromatic ring, the low dielectric property can be improved.

[0124] On the other hand, from the perspective of clarifying the content ratio of the reaction product of the styrene-based elastomer and the resin containing an aromatic ring in the low dielectric resin composition, it is also considered to use the polystyrene-equivalent molecular weight at the peak top of peak C attributed to the reaction product of the styrene-based elastomer and the resin containing an aromatic ring.

[0125] However, when the content ratio of the reaction product of the styrene-based elastomer and the resin containing an aromatic ring is small, peak C may be hidden by peak A and peak C may not appear.

[0126] On the other hand, by using the polystyrene-equivalent molecular weight of the polystyrene-equivalent molecular weight (M2) at position D, the content ratio of the reaction product of the styrene-based elastomer and the resin containing an aromatic ring can be estimated.

[0127] On the other hand, if the above ratio is less than the above lower limit, the low dielectric property deteriorates.

[0128] Moreover, being excellent in low dielectric property specifically means that the relative dielectric constant Dk detailed in the examples described later is, for example, 2.25 or less, preferably 2.20 or less, more preferably 2.15 or less, still more preferably 2.10 or less, particularly preferably 2.05 or less, and most preferably 2.00 or less.

[0129] Since the low dielectric resin composition is excellent in low dielectric property, it is preferably used as an adhesion promoter and / or a low dielectric adhesive in the production of the laminate described later. That is, the adhesion promoter and the low dielectric adhesive each contain the above low dielectric resin composition.

[0130] 2. Laminate The laminate is a circuit board or a circuit board material. The circuit board is, for example, a laminate having a conductor layer (circuit layer) with a circuit pattern. The circuit board material is a laminate that can be processed into a circuit board. More specifically, the circuit board material is, for example, a laminate having a conductor layer (non-circuit layer) without a circuit pattern and capable of forming a circuit pattern by processing. Examples of the circuit board material include copper-clad laminates.

[0131] The laminate is manufactured by using a low-dielectric resin composition. Hereinafter, a method for manufacturing a circuit board or a circuit board material as a laminate using the low-dielectric resin composition will be described in detail.

[0132] (1) First Embodiment FIG. 1 is a schematic cross-sectional view showing a copper-clad laminate as a first embodiment of the laminate. In the first embodiment, the above-mentioned low-dielectric resin composition is used as an adhesion promoter.

[0133] More specifically, in FIG. 1, the copper-clad laminate 1 includes an insulating layer having adhesiveness (hereinafter, adhesive insulating layer) 2 and a conductor layer 4 disposed on at least one surface of the adhesive insulating layer 2.

[0134] The adhesive insulating layer 2 includes a low-dielectric and adhesive low-dielectric adhesive molding. The adhesive insulating layer 2 preferably consists of a low-dielectric adhesive molding or consists of an impregnated substrate and a low-dielectric adhesive molding.

[0135] The low-dielectric adhesive molding is, for example, a cured product (molded cured product) of a low-dielectric adhesive molding material.

[0136] The low-dielectric adhesive molding material includes, for example, a thermosetting resin (uncured thermosetting resin) and an adhesion promoter (additive).

[0137] Examples of the thermosetting resin include epoxy resin, polyphenylene ether resin, fluororesin, polyimide resin, phenol resin, melamine resin, polyolefin resin having an unsaturated double bond, and liquid crystal polymer. These may be used alone or in combination of two or more. As the thermosetting resin, preferably, polyphenylene ether resin is mentioned.

[0138] In other words, the thermosetting resin contains at least one selected from the group consisting of epoxy resin, polyphenylene ether resin, fluororesin, polyimide resin, phenol resin, melamine resin, polyolefin resin having an unsaturated double bond, and liquid crystal polymer. The thermosetting resin preferably contains polyphenylene ether resin. The thermosetting resin preferably consists of polyphenylene ether resin.

[0139] The adhesion-imparting agent (additive) contains the above-described low-dielectric resin composition and preferably consists of the above-described low-dielectric resin composition.

[0140] The low-dielectric adhesion molding material is prepared, for example, by mixing a thermosetting resin and an adhesion-imparting agent by a known method.

[0141] The mixing ratio of the thermosetting resin and the adhesion-imparting agent is not particularly limited, but the adhesion-imparting agent is, for example, 1 to 400 parts by mass, preferably 5 to 150 parts by mass with respect to 100 parts by mass of the thermosetting resin.

[0142] Also, the thermosetting resin is, for example, 20 to 99% by mass, preferably 40 to 95% by mass with respect to the total amount of the thermosetting resin and the adhesion-imparting agent.

[0143] Also, the adhesion-imparting agent is, for example, 1 to 80% by mass, preferably 5 to 60% by mass with respect to the total amount of the thermosetting resin and the adhesion-imparting agent.

[0144] The low-dielectric adhesion molding material can contain an additive if necessary.

[0145] Examples of the additive include the additives exemplified in the above low dielectric constant resin composition.

[0146] From the viewpoint of thermosetting, the low dielectric adhesive molding material preferably contains a thermal initiator.

[0147] When the adhesive insulating layer 2 is made of a low dielectric adhesive molded article, the adhesive insulating layer 2 is formed by molding and curing a low dielectric adhesive molding material by a known method.

[0148] Specifically, the low dielectric adhesive molding material is applied to a known base material (for example, a copper plate and a release liner), and dried if necessary. Thereby, a coating film of the low dielectric adhesive molding material is obtained. Then, the coating film is cured (thermoset) by heating.

[0149] Thereby, a low dielectric adhesive molded article (adhesive insulating layer 2) made of a cured product of the low dielectric adhesive molding material is obtained.

[0150] When the adhesive insulating layer 2 is made of an impregnated base material and a low dielectric adhesive molded article, the adhesive insulating layer 2 is formed by impregnating the impregnated base material with the low dielectric adhesive molding material and drying and curing it.

[0151] Specifically, the low dielectric adhesive molding material is impregnated into a glass cloth as an impregnated base material, and dried if necessary. Then, the glass cloth and the low dielectric adhesive molding material impregnated into the glass cloth are cured (thermoset) by heating.

[0152] Thereby, a low dielectric adhesive molded article (adhesive insulating layer 2) containing the glass cloth and the cured product of the low dielectric adhesive molding material is obtained.

[0153] Note that the shape and size of the low dielectric adhesive molded article (adhesive insulating layer 2) are appropriately set according to the purpose and application.

[0154] The conductor layer 4 is a thin film made of a known conductive material. Examples of the conductive material include copper. The conductor layer 4 is formed by a known film-forming method. The thickness of the conductor layer 4 is adjusted to be relatively thin, for example. Thereby, the circuit pattern can be formed by the subtractive method. The thickness of the conductor layer 4 is, for example, 50 μm or less.

[0155] The conductor layer 4 is disposed on at least one surface of the adhesive insulating layer 2. Preferably, the conductor layer 4 is disposed on both surfaces of the adhesive insulating layer 2. In FIG. 1, the conductor layer 4 is disposed on both surfaces of the adhesive insulating layer 2.

[0156] More specifically, the conductor layer 4 is formed by a known method so as to be in contact with the surface of the adhesive insulating layer 2. Thereby, the conductor layer 4 is adhered to the adhesive insulating layer 2. As a result, the copper-clad laminate 1 including the adhesive insulating layer 2 and the conductor layer 4 is obtained.

[0157] Note that the method for obtaining the copper-clad laminate 1 is not limited to the above. For example, first, a conductor layer 4 made of a metal foil is prepared. Next, a low dielectric adhesive molding material is applied to the conductor layer 4 and dried if necessary. Then, the low dielectric adhesive molding material is thermally cured. Thereby, the adhesive insulating layer 2 can be formed on the surface of the conductor layer 4. As a result, the copper-clad laminate 1 including the adhesive insulating layer 2 and the conductor layer 4 in contact with the surface of the adhesive insulating layer 2 is obtained.

[0158] The above copper-clad laminate 1 has an insulating layer 2. The insulating layer 2 includes the above low dielectric adhesive molding product. Therefore, in the copper-clad laminate 1, the insulating layer 2 is excellent in low dielectric properties.

[0159] In addition, the above adhesion promoter (additive), low dielectric adhesive molding material, and low dielectric adhesive molding product (adhesive insulating layer 2) include the above low dielectric resin composition. Therefore, the adhesion promoter (additive), low dielectric adhesive molding material, and low dielectric adhesive molding product (adhesive insulating layer 2) are excellent in low dielectric properties.

[0160] (2) Second Embodiment FIG. 2 is a schematic cross-sectional view showing a circuit board as a second embodiment of the laminate. In the second embodiment, similarly to the first embodiment, the above-described low-dielectric resin composition is used as an adhesion-imparting agent.

[0161] More specifically, the copper-clad laminate 1 of the above-described first embodiment can be processed to form a circuit board 11. That is, the conductor layer 4 of the copper-clad laminate 1 can be etched by a known method to form a circuit 14. As a result, as shown in FIG. 2, a circuit board 11 as a second embodiment of the laminate is formed.

[0162] In such a circuit board 11, the adhesive insulating layer 2 contains a low-dielectric adhesive molding. Therefore, in the circuit board 11, the adhesive insulating layer 2 is excellent in low-dielectric properties.

[0163] (3) Third Embodiment FIG. 3 is a schematic cross-sectional view showing a copper-clad laminate as a third embodiment of the laminate. In the third embodiment, the above-described low-dielectric resin composition is used as a low-dielectric adhesive.

[0164] In FIG. 3, the copper-clad laminate 21 includes an insulating layer 22, a conductor layer 24 disposed opposite to the insulating layer 22, and an adhesive layer 23 disposed between the insulating layer 22 and the conductor layer 24 and bonding the insulating layer 22 and the conductor layer 24. In the copper-clad laminate 21, the adhesive layer 23 is formed from the above-described low-dielectric adhesive.

[0165] The insulating layer 22 is, for example, an insulating layer having no adhesiveness (non-adhesive insulating layer). The insulating layer 22 contains, for example, the above-described thermosetting resin. The insulating layer 22 preferably consists of the above-described thermosetting resin.

[0166] The conductor layer 24 is a thin film made of a known conductive material, similar to the above-mentioned conductor layer 4. Examples of the conductive material include copper. The conductor layer 24 is formed by a known film-forming method. The thickness of the conductor layer 24 is adjusted to be relatively thin, for example. Thereby, the circuit pattern can be formed by the subtractive method. The thickness of the conductor layer 24 is, for example, 50 μm or less.

[0167] The adhesive layer 23 is interposed between the insulating layer 22 and the conductor layer 24. The adhesive layer 23 is a dried product of a low-dielectric adhesive. The low-dielectric adhesive includes, for example, the above-mentioned low-dielectric resin composition. The low-dielectric adhesive is preferably a diluted solution of the above-mentioned low-dielectric resin composition.

[0168] When manufacturing the copper-clad laminate 21, for example, first, the insulating layer 22 and the conductor layer 24 are prepared. Next, a low-dielectric adhesive is applied to one surface of the insulating layer 22. Thereafter, the conductor layer 24 is adhered to one surface of the low-dielectric adhesive, and the low-dielectric adhesive is dried. Thereby, the copper-clad laminate 21 is obtained. Note that the copper-clad laminate 21 can also be manufactured in the reverse order described above. That is, in this method, a low-dielectric adhesive is applied to one surface of the conductor layer 24. Thereafter, the insulating layer 22 is adhered to one surface of the low-dielectric adhesive, and the low-dielectric adhesive is dried. Thereby, the copper-clad laminate 21 is obtained.

[0169] In the above-mentioned copper-clad laminate 21, the insulating layer 22 and the conductor layer 24 are adhered by the adhesive layer 23 (low-dielectric adhesive). That is, the copper-clad laminate 21 has the adhesive layer 23. And the adhesive layer 23 (low-dielectric adhesive) includes the above-mentioned low-dielectric resin composition. Therefore, in the copper-clad laminate 21, the adhesive layer 23 (low-dielectric adhesive) is excellent in low-dielectric properties.

[0170] In the copper-clad laminate 21 of the above-described third embodiment, the adhesive layer 23 and the conductor layer 24 are formed only on one surface of the insulating layer 22. However, the adhesive layer 23 and the conductor layer 24 may be formed on both surfaces of the insulating layer 22. Further, in such a case, the copper-clad laminate 21 may not have the insulating layer 22. That is, the conductor layer 24 may be formed on both surfaces of the adhesive layer 23. In other words, two conductor layers 24 may be adhered by the adhesive layer 23. In such a case, the adhesive layer 23 also serves as the insulating layer 22.

[0171] (4) Fourth Embodiment FIG. 4 is a schematic cross-sectional view showing a circuit board as a fourth embodiment of the laminate. In the fourth embodiment, similar to the third embodiment, the above-described low-dielectric resin composition is used as a low-dielectric adhesive.

[0172] More specifically, the copper-clad laminate 21 of the above-described third embodiment can be processed to form the circuit board 31. More specifically, the conductor layer 24 of the copper-clad laminate 21 can be etched by a known method to form the circuit 34. As a result, as shown in FIG. 4, the circuit board 31 as a fourth embodiment of the laminate is formed.

[0173] In such a circuit board, the insulating layer 22 and the circuit 34 composed of the conductor layer are adhered by the adhesive layer 23.

[0174] In such a circuit board 31, the insulating layer 22 and the circuit 34 composed of the conductor layer are adhered by the adhesive layer 23 (low-dielectric adhesive). The adhesive layer 23 (low-dielectric adhesive) contains the above-described low-dielectric resin composition. Therefore, in the circuit board 31, the adhesive layer 23 (low-dielectric adhesive) is excellent in low-dielectric properties.

[0175] In the circuit board 31 of the above-described fourth embodiment, the adhesive layer 23 and the circuit 34 are formed only on one surface of the insulating layer 22. However, the adhesive layer 23 and the circuit 34 may be formed on both surfaces of the insulating layer 22. Further, in such a case, the circuit board 31 may not have the insulating layer 22. That is, the circuits 34 may be formed on both surfaces of the adhesive layer 23. In other words, two circuits 34 may be adhered by the adhesive layer 23. In such a case, the adhesive layer 23 also serves as the insulating layer 22.

[0176] (5) Fifth Embodiment FIGS. 5 to 8 are cross-sectional process diagrams for manufacturing a circuit board as a fifth embodiment of the laminate. In the fifth embodiment, the above-described low-dielectric resin composition is used as a low-dielectric adhesive.

[0177] In FIGS. 5 to 8, the circuit board 41 is a multilayer circuit board having at least two conductor layers. More specifically, as shown in FIG. 8O being referred to, the circuit board 41 includes a first conductor layer 40, a second conductor layer 50 disposed opposite to the first conductor layer 40, and an adhesive layer 51 disposed between the first conductor layer 40 and the second conductor layer 50 and bonding the first conductor layer 40 and the second conductor layer 50. Further, in the circuit board 41, the adhesive layer 51 is formed from the above-described low-dielectric adhesive (preferably, a diluted solution of the low-dielectric resin composition).

[0178] To manufacture such a circuit board 41, first, as shown in FIG. 5A, a copper foil with a carrier 42 is prepared. The copper foil with a carrier 42 includes a carrier layer 43 and a copper foil 44 laminated on one surface of the carrier layer 43.

[0179] The carrier layer 43 is not particularly limited, and examples include known release sheets. The copper foil 44 is laminated on the carrier layer 43 by a known method. The thickness of the copper foil 44 is appropriately set according to the purpose and application. Further, the copper foil 44 is surface-treated as necessary. Examples of the surface treatment include roughening treatment.

[0180] Next, in this method, as shown in FIG. 5B, a first resist layer 45 having a predetermined shape is formed on the surface of one side of the copper foil 44. The first resist layer 45 is formed, for example, by applying a known resist solution and performing exposure and development. Also, the first resist layer 45 can be formed by exposing and etching a dry film resist.

[0181] Next, in this method, as shown in FIG. 5C, a first plating layer 46 is formed. The first plating layer 46 is formed, for example, by an electrolytic plating method. In the electrolytic plating method, for example, the carrier layer 43, the copper foil 44, and the first resist layer 45 are immersed in an electrolytic plating solution, and then the copper foil 44 is supplied with electricity. As a result, a first plating layer 46 is formed on the surface of one side of the copper foil 44 in an inverted pattern of the first resist layer 45. That is, the first plating layer 46 has a circuit pattern.

[0182] Next, in this method, as shown in FIG. 6D, the first resist layer 45 is removed by a known method. Next, in this method, as shown in FIG. 6E, the copper foil 44 exposed from the first plating layer 46 is removed by a known method. As a result, a first conductor layer 40 including the remaining copper foil 44 that is not removed and the first plating layer 46 laminated on the copper foil 44 is formed. That is, the first conductor layer 40 includes the copper foil 44 and the first plating layer 46. The first conductor layer 40 preferably consists of the copper foil 44 and the first plating layer 46.

[0183] Next, in this method, as shown in FIG. 6F, an adhesive layer 51 made of a low dielectric adhesive is laminated on the carrier layer 43, the first plating layer 46, and the copper foil 44.

[0184] More specifically, in this method, for example, a cast film of a low dielectric adhesive is prepared. Next, the cast film is pressure-bonded to the carrier layer 43, the first plating layer 46, and the copper foil 44. As a result, the cast film covers the first plating layer 46 and the copper foil 44. Also, the cast film forms the adhesive layer 51.

[0185] On the one hand, in this method, a copper foil with a carrier 52 is separately prepared. The copper foil with a carrier 52 includes a carrier layer 53 and a copper foil 54 laminated on the other surface of the carrier layer 53. And in this method, as shown in FIG. 6G, the copper foil 54 of the copper foil with a carrier 52 is laminated on the adhesive layer 51.

[0186] Next, in this method, as shown in FIG. 7H, the carrier layer 53 of the copper foil with a carrier 52 is peeled off. Then, in this method, as shown in FIG. 7I, the copper foil 54 and the adhesive layer 51 are opened by a known method to form via holes 58. Also, the first plating layer 46 is exposed from the via holes 58. Next, in this method, as shown in FIG. 7J, the via holes 58 are filled with a conductive material to form via fills 59. Note that examples of the conductive material include copper.

[0187] Next, in this method, as shown in FIG. 7K, a second resist layer 55 having a predetermined shape is formed on one surface of the copper foil 54. The second resist layer 55 is formed, for example, by applying a known resist solution and performing exposure and development. Also, similar to the first resist layer 45, the second resist layer 55 can also be formed from a dry film resist.

[0188] Next, in this method, as shown in FIG. 8L, a second plating layer 56 is formed. The second plating layer 56 is formed, for example, by an electrolytic plating method. Thereby, the second plating layer 56 is formed in an inverted pattern of the second resist layer 55 on one surface of the copper foil 54. That is, the second plating layer 56 has a circuit pattern.

[0189] Next, in this method, as shown in FIG. 8M, the second resist layer 55 is removed by a known method. Next, in this method, as shown in FIG. 8N, the copper foil 54 exposed from the second plating layer 56 is removed by a known method. As a result, a second conductor layer 50 is formed, which includes the copper foil 54 that remains without being removed and the first plating layer 56 laminated on the copper foil 54. That is, the second conductor layer 50 includes the copper foil 54 and the second plating layer 56. The second conductor layer 50 preferably consists of the copper foil 54 and the second plating layer 56.

[0190] Thereafter, in this method, as shown in FIG. 8O, the carrier layer 43 is peeled off. As a result, the copper foil 44 is exposed. As a result, the circuit board 1 is formed.

[0191] In the circuit board 41 described above, the first conductor layer 40 and the second conductor layer 50 are adhered by an adhesive layer 51 (low dielectric adhesive). That is, the circuit board 41 has the adhesive layer 51. And the adhesive layer 51 (low dielectric adhesive) contains the above low dielectric resin composition. Therefore, in the circuit board 41, the adhesive layer 51 (low dielectric adhesive) is excellent in low dielectric properties.

[0192] 4. Operational Effects The low dielectric resin composition includes essential resin components composed of a styrene-based elastomer, a resin containing an aromatic ring, and a reaction product of the styrene-based elastomer and the resin containing an aromatic ring. In the molecular weight distribution of the essential resin components by gel permeation chromatography, the ratio (M2 / M1) of the polystyrene-equivalent molecular weight (M2) at position D, which is located on the higher molecular weight side than the peak top A' of peak A attributed to the styrene-based elastomer and has a peak intensity of 10% of the peak intensity of peak top A', to the polystyrene-equivalent molecular weight (M1) of peak top A' is 1.7 or more. Therefore, it is excellent in low dielectric properties.

[0193] Specifically, in the production of the low dielectric resin composition, a peroxide is blended together with a styrene-based elastomer and a resin containing an aromatic ring, and the styrene-based elastomer and the resin containing an aromatic ring are reacted. Therefore, the resulting low dielectric resin composition contains a reaction product of the styrene-based elastomer and the resin containing an aromatic ring. And in the low dielectric resin composition, the ratio (M2 / M1) of the polystyrene-reduced molecular weight (M2) at the above position D to the polystyrene-reduced molecular weight (M1) of the peak top A' of peak A attributed to the styrene-based elastomer is 1.7 or more.

[0194] That is, the low dielectric resin composition contains a reaction product of a styrene-based elastomer and a resin containing an aromatic ring at a predetermined ratio. And such a reaction product can improve the low dielectric property.

[0195] The adhesion promoter contains the above low dielectric resin composition. Therefore, it is excellent in low dielectric property.

[0196] The low dielectric adhesive molding material contains the above adhesion promoter. Therefore, it is excellent in low dielectric property.

[0197] The low dielectric adhesive molded article contains a cured product of the above low dielectric adhesive molding material. Therefore, it is excellent in low dielectric property.

[0198] The low dielectric adhesive contains the above low dielectric resin composition. Therefore, it is excellent in low dielectric property.

Examples

[0199] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited by the following examples. Note that "parts" and "%" are based on mass unless otherwise specified. In addition, the specific numerical values such as the blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values (numerical values defined as "hereinafter" and "less than") or lower limit values (numerical values defined as "above" and "exceeding") of the corresponding blending ratios (content ratios), physical property values, parameters, etc. described in the above "Mode for Carrying Out the Invention".

[0200] <Details of Components> Details of the abbreviations used in each example and each comparative example are described below. Styrenic elastomer 1: Trade name "Kraton G1730", manufactured by Kraton Polymer Japan, styrene - ethylene - propylene - styrene copolymer (SEPS), styrene unit content 20% by mass, weight - average molecular weight 94000 Styrenic elastomer 2: Trade name "SEPTON2002", manufactured by Kuraray, styrene - ethylene - propylene - styrene copolymer (SEPS), styrene unit content 30% by mass, weight - average molecular weight 54000 Styrenic elastomer 3: Trade name "Kraton G1652", manufactured by Kraton Polymer Japan, styrene - ethylene - butylene - styrene copolymer (SEBS), styrene unit content 30% by mass, weight - average molecular weight 75000 Styrenic elastomer 4: Trade name "SEPTON8007", manufactured by Kuraray, styrene - ethylene - butylene - styrene copolymer (SEBS), styrene unit content 30% by mass, weight - average molecular weight 75000 Styrenic elastomer 5: Trade name "SEPTON4033", manufactured by Kuraray, styrene - ethylene - ethylene - propylene - styrene copolymer (SEEPS), styrene unit content 30% by mass, weight - average molecular weight 87000 Styrenic elastomer 6: Trade name "SEPTON2104", manufactured by Kuraray Co., Ltd., styrene - ethylene - propylene - styrene copolymer (SEPS), styrene unit content 65% by mass, weight - average molecular weight 78000 ST: Styrene IPT: Isopropenyltoluene IND: Indene nBA: Normal butyl acrylate IBX: Isobornyl methacrylate GMA: Glycidyl methacrylate C5: C5 fraction

[0201] <Production of resin containing aromatic ring> Production Example 1 Charge 100 parts by mass of xylene into a nitrogen - purged flask and heat it up. Under reflux of xylene, a mixed solution prepared by previously mixing and dissolving 40 parts by mass of styrene, 60 parts by mass of isobornyl methacrylate, and 10 parts by mass of t - butyl peroxy - 2 - ethylhexanoate is continuously added over 5 hours, and then refluxed for 1 hour. Thereafter, the internal temperature is maintained at 98 °C, 0.5 part by weight of t - butyl peroxy - 2 - ethylhexanoate is added and reacted for 1 hour, and further 0.5 part by weight of t - butyl peroxy - 2 - ethylhexanoate is added and reacted for 2 hours to obtain a polymerization solution. The obtained polymerization solution is flash - distilled in a vessel at 190 °C and 1.33 kPa to distill off the solvent and the like, thereby obtaining a resin containing an aromatic ring.

[0202] Production Examples 2 to 6 Based on the same procedure as in Production Example 1, a resin containing an aromatic ring was obtained. However, the formulation of each component was changed based on Table 1.

[0203] <Production of low - dielectric resin composition> Example 1 80 parts by mass of a styrene-based elastomer, 20 parts by mass of the resin containing an aromatic ring of Production Example 1, and 0.6 parts by mass of 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane as a peroxide were mixed and melt-kneaded at 230°C using a twin-screw kneading extruder with a vent. Thereafter, cooling and pelletization were carried out to obtain pellets of the low dielectric resin composition. Next, 100 parts by mass of these pellets were dissolved in 400 parts by mass of toluene in a heating environment to obtain a diluted solution of the low dielectric resin composition (solid content concentration: 20% by mass).

[0204] Examples 2 to 11 Based on the same procedure as in Example 1, a diluted solution of the low dielectric resin composition was obtained. However, the compounding formulation of each component was changed based on Table 2.

[0205] Comparative Examples 1 to 5 Based on the same procedure as in Example 1, a diluted solution of the low dielectric resin composition was obtained. However, no peroxide was compounded, and the compounding formulation of each component was changed based on Table 2.

[0206] <Evaluation> (Weight average molecular weight and dispersity) Regarding the resin containing an aromatic ring of each production example, the weight average molecular weight and dispersity were measured based on the following conditions. The results are shown in Table 2. Also, regarding the low dielectric resin composition of each example and each comparative example, the molecular weight distribution was measured using gel permeation chromatography, and M2 / M1 was calculated. The results are shown in Table 2. Also, the molecular weight distributions of Example 3 and Comparative Example 4 are shown in FIG. 9. {Conditions} Analytical device: Gel permeation chromatography (manufactured by Shimadzu Corporation; LC-10series) Detector: Manufactured by Shimadzu Corporation; C-R4A Column: TSKG 6000H - TSKG 4000H - TSKG 3000H - TSKG 2000H (manufactured by Tosoh Corporation) Mobile phase: Tetrahydrofuran Measurement temperature: 40°C Flow rate: 0.8 ml / min Standard substance: Polystyrene (Dielectric property) Diluted solutions of the low-dielectric resin compositions of the respective examples and comparative examples were applied to a release film (polyethylene terephthalate film, thickness 100 μm) and dried at 100°C for 1 minute. As a result, a dried coating film (film thickness of approximately 60 μm) of the low-dielectric resin composition was obtained. Next, the obtained dried coating film was formed into a strip shape, and the relative permittivity Dk of the dried coating film was measured in accordance with JIS R1641 (2007). In the measurement, a cavity resonator (vector network analyzer HP8510B (manufactured by Keysight Technologies)) was used. The measurement frequency was set to 10 GHz. The results are shown in Table 2. It can be seen that the lower the relative permittivity Dk, the better the low-dielectric property.

[0207] <Discussion> In Comparative Example 4, a peroxide is not blended with the styrene-based elastomer and the resin containing an aromatic ring. Therefore, the styrene-based elastomer and the resin containing an aromatic ring do not react, and the low-dielectric resin composition does not contain the reaction product of the styrene-based elastomer and the resin containing an aromatic ring. This is also clear from the fact that, as shown in Fig. 9, in the molecular weight distribution of gel permeation chromatography for the essential resin components, peak C attributed to the reaction product of the styrene-based elastomer and the resin containing an aromatic ring is not observed. And in Comparative Example 4, M2 / M1 is 1.5. That is, it can be seen that when the low-dielectric resin composition does not contain the reaction product of the styrene-based elastomer and the resin containing an aromatic ring, M2 / M1 is 1.5. Also, from the evaluation of the dielectric property, it can be seen that the low-dielectric property decreases.

[0208] On the other hand, in Example 3, a peroxide is blended with a styrenic elastomer and a resin containing an aromatic ring, and the styrenic elastomer and the resin containing an aromatic ring are reacted. Therefore, the low dielectric resin composition contains a reaction product of the styrenic elastomer and the resin containing an aromatic ring. This is also clear from the fact that, as shown in Fig. 9, for the essential resin components, a peak C attributable to the reaction product of the styrenic elastomer and the resin containing an aromatic ring is observed in the molecular weight distribution of gel permeation chromatography. And in Example 3, M2 / M1 is 1.7 or more. Therefore, it can be seen that the low dielectric property is excellent.

[0209]

Table 1

[0210]

Table 2

Explanation of symbols

[0211] 1, 21 Copper-clad laminate 2 Adhesive insulating layer 4, 24 Conductor layer 22 Insulating layer 23, 51 Adhesive layer 40 First conductor layer 50 Second conductor layer

Claims

1. A styrenic elastomer, a resin containing an aromatic ring, and a reaction product of the styrenic elastomer and the resin containing an aromatic ring, comprising an essential resin component, wherein in the molecular weight distribution of the essential resin component by gel permeation chromatography, the ratio (M2 / M1) of the polystyrene-equivalent molecular weight (M2) at a position located on the higher molecular weight side than the peak top of the peak attributed to the styrenic elastomer and having a peak intensity of 10% of the peak intensity of the peak top to the polystyrene-equivalent molecular weight (M1) of the peak top is 1.7 or more, a low dielectric resin composition.

2. The low dielectric resin composition according to claim 1, wherein the polystyrene-equivalent weight average molecular weight of the resin containing an aromatic ring is 1,000 or more and 50,000 or less.

3. The resin containing an aromatic ring is a polymer of a polymerization component containing an aromatic ring-containing monomer, and the content ratio of the aromatic ring-containing monomer is 30% by mass or more with respect to the polymerization component. The low dielectric resin composition according to claim 1.

4. The styrenic elastomer contains a structural unit derived from styrene, and the content ratio of the structural unit derived from styrene is 20% by mass or more and 70% by mass or less with respect to the total amount of the styrenic elastomer. The low dielectric resin composition according to claim 1.

5. An adhesion-imparting agent containing the low dielectric resin composition according to any one of claims 1 to 4.

6. Containing a thermosetting resin and the adhesion-imparting agent according to claim 5, wherein the thermosetting resin contains at least one selected from the group consisting of an epoxy resin, a polyphenylene ether resin, a fluororesin, a polyimide resin, a phenol resin, a melamine resin, a polyolefin resin having an unsaturated double bond, and a liquid crystal polymer. A low dielectric adhesive molding material.

7. A low dielectric adhesive molded article containing a cured product of the low dielectric adhesive molding material according to claim 6.

8. An insulating layer containing the low dielectric adhesive molded article according to claim 7, and a conductor layer disposed on at least one surface of the insulating layer A laminate comprising.

9. A low dielectric adhesive containing the low dielectric resin composition according to any one of claims 1 to 4.

10. An insulating layer, a conductor layer disposed opposite to the insulating layer, and an adhesive layer disposed between the insulating layer and the conductor layer for adhering the insulating layer and the conductor layer Comprising, A laminate, wherein the adhesive layer contains the low-dielectric adhesive according to claim 9.

11. A first conductor layer, A second conductor layer disposed opposite to the first conductor layer, An adhesive layer disposed between the first conductor layer and the second conductor layer and bonding the first conductor layer and the second conductor layer and comprising A laminate, wherein the adhesive layer contains the low-dielectric adhesive according to claim 9.

12. A method for producing a low-dielectric adhesiveness molded article according to any one of claims 1 to 4, A method for producing a low-dielectric resin composition, comprising mixing a styrene-based elastomer, a resin containing an aromatic ring, and a peroxide to react the styrene-based elastomer and the resin containing the aromatic ring.

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