JP2022018376A - Resin composition and conductor substrate - Google Patents

Abstract

To provide a novel resin composition that is free of halogen and has flame retardancy, and a conductor substrate having a resin layer formed from the resin composition.SOLUTION: A resin composition according to one embodiment contains a rubber component, a crosslink component having an epoxy group, a curing agent, polyphenylene ether, a phosphorus flame retardant, a melamine flame retardant, and a hindered amine.SELECTED DRAWING: None

Description

The present invention relates to a resin composition and a conductor substrate.

The speed and capacity of signals used in mobile communication devices such as mobile phones, their base station devices, servers, network infrastructure devices such as routers, and electronic devices such as large computers are increasing year by year. Along with this, the printed wiring boards mounted on these electronic devices need to be compatible with high frequencies, and there is a demand for a substrate material having a low relative permittivity and a low dielectric loss tangent that can reduce transmission loss. In recent years, as applications that handle such high-frequency signals, in addition to the above-mentioned electronic devices, practical application and practical planning of new systems that handle high-frequency wireless signals in the ITS field (automobiles, transportation system-related) and indoor short-range communication fields. It is expected that low transmission loss substrate materials will be further required for printed wiring boards mounted on these devices in the future.

The material for the printed wiring board is required to have flame retardancy. Due to recent environmental problems, environmentally friendly halogen-free flame retardancy has been studied in laminated boards for printed wiring boards (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2008-184591 Japanese Unexamined Patent Publication No. 2019-123769

For the printed wiring board, it is necessary to use a halogen-free resin material with higher flame retardancy than before. Therefore, an object of the present invention is to provide a novel resin composition that is halogen-free and has flame retardancy, and a conductor substrate having a resin layer formed from the resin composition.

One aspect of the present disclosure relates to a resin composition containing a rubber component, a cross-linking component having an epoxy group, a curing agent, a polyphenylene ether, a phosphorus-based flame retardant, a melamine-based flame retardant, and a hindered amine.

Another aspect of the present disclosure comprises a resin layer and a conductor foil provided on at least one surface of the resin layer opposite to the substrate film, wherein the resin layer is the resin composition described above. Concerning conductor substrates, including cured products.

According to the present invention, it is possible to provide a novel resin composition that is halogen-free and has flame retardancy, and a conductor substrate having a resin layer formed from the resin composition.

Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[Resin composition]
The resin composition according to the present embodiment contains a rubber component, a cross-linking component having an epoxy group, a curing agent, a polyphenylene ether, a phosphorus-based flame retardant, a melamine-based flame retardant, and a hindered amine. Such a resin composition can form a cured product having excellent flame retardancy even if it is halogen-free.

(Rubber component)
The rubber components include, for example, acrylic rubber, isoprene rubber, butyl rubber, styrene butadiene rubber, butadiene rubber, acrylonitrile butadiene rubber, silicone rubber, urethane rubber, chloroprene rubber, ethylene propylene rubber, fluororubber, sulfide rubber, epichlorohydrin rubber, and chlorination. It can contain at least one rubber selected from the group consisting of butyl rubber. From the viewpoint of protecting the wiring from damage due to moisture absorption or the like, a rubber component having low gas permeability may be used. From this point of view, the rubber component may contain at least one selected from styrene-butadiene rubber, butadiene rubber, and butyl rubber. By using styrene-butadiene rubber, the resistance of the resin layer to various chemicals used in the plating process is improved, and a wiring board can be manufactured with a high yield.

Examples of commercially available acrylic rubber products include Zeon Corporation's "Nipol AR series" and Kuraray Corporation's "Clarity series". Examples of commercially available isoprene rubber include Zeon Corporation's "Nipol IR Series". Examples of commercially available butyl rubber products include JSR Corporation "BUTYL series". Examples of commercially available styrene-butadiene rubber products include JSR Corporation "Dynaron SEBS series", "Dynaron HSBR series", and Clayton Polymer Japan Co., Ltd. Examples include "Clayton D Polymer Series" and Aron Kasei Co., Ltd. "AR Series". As a commercially available product of butadiene rubber, for example, "Nipol BR series" of Nippon Zeon Corporation can be mentioned. Examples of commercially available acrylonitrile butadiene rubber include JSR Corporation "JSR NBR Series". Examples of commercially available silicone rubber products include Shin-Etsu Silicone Co., Ltd. "KMP series". Examples of commercially available ethylene propylene rubber include JSR Corporation "JSR EP Series". Examples of commercially available fluororubber products include Daikin Corporation's "Daiel Series". Examples of commercially available products of epichlorohydrin rubber include ZEON CORPORATION "Hydrin Series".

The rubber component can also be produced synthetically. For example, acrylic rubber can be obtained by reacting (meth) acrylic acid, (meth) acrylic acid ester, aromatic vinyl compound, vinyl cyanide compound and the like.

The rubber component may include rubber having a cross-linking group. By using a rubber having a cross-linking group, the heat resistance of the stretchable resin layer tends to be easily improved. The cross-linking group may be any reactive group capable of advancing the reaction of cross-linking the molecular chain of the rubber component. Examples thereof include a reactive group, an acid anhydride group, an amino group, a hydroxyl group, an epoxy group and a carboxyl group contained in a cross-linking component having an epoxy group, which will be described later.

The rubber component may contain a rubber having at least one cross-linking group of an acid anhydride group and a carboxyl group. Examples of rubbers having an acid anhydride group include rubbers partially modified with maleic anhydride. The rubber partially modified with maleic anhydride is a polymer containing a structural unit derived from maleic anhydride. As a commercially available product of rubber partially modified with maleic anhydride, for example, there is a styrene-based elastomer "Toughprene 912" manufactured by Asahi Kasei Corporation.

The rubber partially modified with maleic anhydride may be a hydrogenated styrene-based elastomer partially modified with maleic anhydride. The hydrogenated styrene-based elastomer can also be expected to have effects such as improving weather resistance. The hydrogenated styrene-based elastomer is an elastomer obtained by adding hydrogen to an unsaturated double bond of a styrene-based elastomer having a soft segment containing an unsaturated double bond. Commercially available products of hydrogenated styrene-based elastomer partially modified with maleic anhydride include, for example, "FG1901" and "FG1924" of Kraton Polymer Japan Co., Ltd., "Tough Tech M1911" and "Tough Tech M1913" of Asahi Kasei Corporation. , "Tough Tech M1943".

The weight average molecular weight (Mw) of the rubber component may be 20000 to 200,000, 30,000 to 150,000, or 50,000 to 125,000 from the viewpoint of coating film property. Here, Mw means a standard polystyrene conversion value obtained by gel permeation chromatography (GPC).

In the resin composition, the content of the rubber component is preferably 60 to 95% by mass, preferably 65 to 90% by mass, based on the total amount of the rubber component, the cross-linking component having an epoxy group, and the curing agent. It is more preferably 70 to 85% by mass, and even more preferably 70 to 85% by mass. When the content of the rubber component is 60% by mass or more, more sufficient elasticity is likely to be obtained, and the rubber component and the cross-linking component tend to be well mixed. When the content of the rubber component is 95% by mass or less, the resin layer tends to have particularly excellent properties in terms of adhesion, insulation reliability, and heat resistance. The content of the rubber component in the resin layer may be within the above range based on the mass of the resin layer.

(Crosslinking component with epoxy group)
The cross-linking component having an epoxy group (hereinafter, may be simply referred to as “cross-linking component”) is a component that is cross-linked during the curing reaction to form a cross-linked polymer. The cross-linking component is not particularly limited as long as it has an epoxy group in the molecule, and can be, for example, a general epoxy resin. The epoxy resin may be monofunctional, bifunctional or polyfunctional, and is not particularly limited, but a bifunctional or polyfunctional epoxy resin may be used in order to obtain sufficient curability.

Examples of the epoxy resin include bisphenol A type, bisphenol F type, phenol novolac type, naphthalene type, dicyclopentadiene type, cresol novolak type and the like. Epoxy resins modified with fat chains can impart flexibility. Examples of the commercially available fat chain-modified epoxy resin include EXA-4816 manufactured by DIC Corporation. From the viewpoint of curability, low tackiness, and heat resistance, a phenol novolac type, a cresol novolak type, a naphthalene type, or a dicyclopentadiene type epoxy resin may be selected. These epoxy resins can be used alone or in combination of two or more.

By combining a rubber having a maleic anhydride group or a carboxyl group and a compound having an epoxy group (epoxy resin), the heat resistance and low moisture permeability of the stretchable resin layer, the adhesion between the stretchable resin layer and the conductive layer, In addition, a particularly excellent effect can be obtained in terms of the low tack of the elastic resin layer. When the heat resistance of the stretchable resin layer is improved, deterioration of the stretchable resin layer in a heating step such as nitrogen reflow can be suppressed. When the stretchable resin layer has a low tack, the conductor substrate or the wiring substrate can be handled with good workability.

The resin composition may contain a cross-linking component other than the cross-linking component having an epoxy group as long as the effect of the present invention is not significantly impaired. The content of the other cross-linking component is preferably less than 10 parts by mass with respect to 100 parts by mass of the cross-linking component having an epoxy group from the viewpoint of more sufficiently reducing the dielectric loss tangent of the stretchable resin layer.

(Hardener)
The curing agent itself is a compound involved in the curing reaction, and can reduce the dielectric loss tangent while improving the heat resistance of the resin layer.

The curing agent is not particularly limited, but an ester-based curing agent can be used from the viewpoint of more sufficiently obtaining the effect of improving heat resistance and the effect of reducing dielectric loss tangent. As the ester-based curing agent, for example, one or two highly reactive ester groups such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds are contained in one molecule. Examples thereof include compounds having the above. Examples of commercially available ester-based curing agents include "EPICLON HPC8000-65T", "EPICLON HPC8000-L-65MT", and "EPICLON HPC8150-60T" (all manufactured by DIC Corporation, trade names). These can be used alone or in combination of two or more.

It is considered that the ester-based curing agent reacts with the cross-linking component as shown in the following formula (I) during the curing reaction. It is considered that a hydroxyl group is not generated in the reaction between such an ester-based curing agent and a cross-linking component, and even if a side reaction occurs, it is difficult to generate a hydroxyl group, and as a result, a low dielectric loss tangent can be realized.

式中、Ｒ^１、Ｒ^２及びＲ^３はそれぞれ独立に、１価の有機基を示すが、本発明の効果がより十分に得られることから、芳香環を有する１価の有機基であってもよい。

In the formula, R ¹ , R ² and R ³ each independently represent a monovalent organic group, but since the effect of the present invention can be more sufficiently obtained, it is a monovalent organic group having an aromatic ring. May be good.

In the resin composition, the total content of the cross-linking component and the curing agent is preferably 5 to 40% by mass, preferably 10 to 35% by mass, based on the total amount of the rubber component, the cross-linking component and the curing agent. Is more preferable, and 15 to 30% by mass is further preferable. When the total content of the cross-linking component and the curing agent is 5% by mass or more, it is easy to obtain sufficient curing, and the resin layer has particularly excellent properties in terms of adhesion, insulation reliability, and heat resistance. Tend to have. When the total content of the cross-linking component and the curing agent is 40% by mass or less, more sufficient elasticity is likely to be obtained, and the rubber component and the cross-linking component tend to be well mixed.

In the resin composition, the content ratio of the cross-linking component and the curing agent is the equivalent ratio of the epoxy group in the epoxy resin and the ester bond in the ester-based curing agent, and is in the range of 4: 5 to 5: 4. Is preferable. When the content ratio is within the above range, more sufficient curing is likely to be obtained, and the stretchable resin layer tends to have particularly excellent properties in terms of adhesion, insulation reliability, and heat resistance.

(Polyphenylene ether)
Since the polyphenylene ether has a structure that is easily carbonized, the flame retardancy of the resin composition can be enhanced. As the polyphenylene ether, a modified polyphenylene ether or a polyphenylene ether derivative may be used. Examples of commercially available products of polyphenylene ether include Zylon S201A and S202A (manufactured by Asahi Kasei Corporation, trade name).

The content of the polyphenylene ether is 1 to 30 parts by mass and 2 to 25 parts by mass with respect to 100 parts by mass of the total amount of the rubber component, the cross-linking component and the curing agent from the viewpoint of the balance between flame retardancy and flexibility. Alternatively, it may be 4 to 20 parts by mass.

(Lin-based flame retardant)
By containing a phosphorus-based flame retardant, the resin composition can form a cured product having autolysis and excellent flame retardancy. One type of phosphorus-based flame retardant may be used alone, or two or more types may be used in combination.

Examples of the phosphorus-based flame retardant include aromatics such as triphenyl phosphate, tricresyl phosphate, trixilenyl phosphate, cresyldiphenyl phosphate, cresyldi-2,6-xylenyl phosphate, and resorcinol bis (diphenyl phosphate). Phosphonate ester; Phosphonate ester such as divinyl phenylphosphonate, diallyl phenylphosphonate, bis (1-butenyl) phenylphosphonate; phenyl diphenylphosphinate, methyl diphenylphosphinate, 9,10-dihydro-9-oxa-10 -Phosphaphenanthrene-10-phosphinic acid esters such as oxide derivatives; phosphazenic compounds such as bis (2-allylphenoxy) phosphazene, dicresylphosphazene; and melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melam polyphosphate, polyphosphorus. Examples thereof include phosphorus-based flame retardant agents such as ammonium acid, phosphorus-containing vinylbenzyl compound, and red phosphorus.

As the phosphorus-based flame retardant, a phosphinic acid metal salt or an aromatic condensed phosphoric acid ester may be used from the viewpoint of further enhancing the flame retardancy of the resin composition. Examples of commercially available phosphorus-based flame retardants include OP930, OP935, OP945 (manufactured by Clariant Chemicals Co., Ltd., trade name) and PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd., trade name).

The content of the phosphorus-based flame retardant is 1 to 30 parts by mass and 2 to 25 parts by mass with respect to 100 parts by mass of the total amount of the rubber component, the cross-linking component, and the curing agent from the viewpoint of the balance between flame retardancy and flexibility. It may be a part, or 4 to 20 parts by mass.

(Melamine flame retardant)
The melamine-based flame retardant can enhance the flame retardancy of the cured product by generating an inert gas containing nitrogen. The melamine-based flame retardant preferably has a 6-membered ring structure having nitrogen. As the melamine-based flame retardant, for example, melamine cyanurate, which is a compound of melamine and isocyanuric acid, can be used. Commercially available products of melamine cyanurate include, for example, MC-4000, MC4500, MC6000 (manufactured by Nissan Chemical Industries, Ltd., trade name) STABIACE MC-20S, MC-5F, MC2010N (manufactured by Sakai Chemical Industries, Ltd., trade name). Can be mentioned.

The content of the melamine-based flame retardant is 1 to 20 parts by mass and 2 to 18 parts by mass with respect to 100 parts by mass of the total amount of the rubber component, the cross-linking component, and the curing agent from the viewpoint of the balance between flame retardancy and flexibility. It may be a part or 4 to 16 parts by mass.

(Hindered Amin)
The hindered amine is preferably a compound having a NOR (alkoxyimino) group, and may be a compound having a triazine skeleton or a compound having a piperidine skeleton. Examples of commercially available products of hindered amines include TINUVIN NOR371, TINUVIN XT850FF, TINUVIN XT855FF, TINUVIN PA123, Flamestab NOR 116FF (manufactured by BASF Japan Ltd., trade name), LA-81 (manufactured by BASF Japan Ltd., trade name). ..

The content of hindered amine is 1 to 10 parts by mass, 2 to 8 parts by mass, or 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the rubber component, the cross-linking component, and the curing agent from the viewpoint of the balance between flame retardancy and flexibility. It may be 4 to 6 parts by mass.

(Curing accelerator)
The resin composition may further contain a curing accelerator. The curing accelerator is a compound that functions as a catalyst for the curing reaction. The curing accelerator may be selected from tertiary amines, imidazoles, organic acid metal salts, phosphorus compounds, Lewis acids, amine complex salts, and phosphines. Among these, imidazole may be used from the viewpoint of storage stability and curability of the varnish of the resin composition. If the rubber component contains a rubber partially modified with maleic anhydride, imidazole compatible with the rubber may be selected.

In the resin composition, the content of the curing accelerator may be 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the rubber component, the cross-linking component and the curing agent. When the content of the curing accelerator is 0.1 part by mass or more, more sufficient curing tends to be obtained. When the content of the curing accelerator is 10 parts by mass or less, more sufficient heat resistance tends to be obtained. From the above viewpoint, the content of the curing accelerator may be 0.3 to 7 parts by mass or 0.5 to 5 parts by mass.

In addition to the above components, the resin composition may contain antioxidants, anti-yellowing agents, ultraviolet absorbers, visible light absorbers, colorants, plasticizers, stabilizers, fillers, leveling agents and the like, if necessary. , Further may be included as long as the effect of the present invention is not significantly impaired.

[Conductor substrate]
The conductor substrate according to one embodiment has a resin layer and a conductor foil provided on at least one surface of the resin layer. The resin layer contains a cured product of the resin composition according to the present embodiment.

(Conductor foil)
The elastic modulus of the conductor foil may be 40 to 300 GPa. Since the elastic modulus of the conductor foil is 40 to 300 GPa, the conductor foil tends to be less likely to break due to the elongation of the wiring board. From the same viewpoint, the elastic modulus of the conductor foil may be 50 GPa or more or 60 GPa or more, or may be 280 GPa or less or 250 GPa or less. The elastic modulus of the conductor foil here can be a value measured by the resonance method.

The conductor foil can be a metal foil. Metal foils include copper foil, titanium foil, stainless steel foil, nickel foil, permaloy foil, 42 alloy foil, koval foil, nichrome foil, beryllium copper foil, phosphor bronze foil, brass foil, white foil, aluminum foil, tin foil, Examples thereof include lead foil, zinc foil, solder foil, iron foil, tantalum foil, niobium foil, molybdenum foil, zirconium foil, gold foil, silver foil, palladium foil, monel foil, inconel foil, and hasteroi foil. From the viewpoint of appropriate elastic modulus and the like, the conductor foil may be selected from copper foil, gold leaf, nickel foil, and iron foil. From the viewpoint of wiring formability, the conductor foil may be a copper foil. The copper foil can easily form a wiring pattern by photolithography without impairing the characteristics of the elastic resin layer. From this point of view, the conductor foil in the present embodiment may form a wiring pattern.

The copper foil is not particularly limited, and for example, electrolytic copper foil and rolled copper foil used for copper-clad laminates, flexible wiring boards, and the like can be used. Examples of commercially available electrolytic copper foils include F0-WS-18 (manufactured by Furukawa Electric Co., Ltd., trade name), NC-WS-20 (manufactured by Furukawa Electric Co., Ltd., trade name), and YGP-12 (Nippon Denkai Co., Ltd.). Company-made, product name), GTS-18 (Furukawa Electric Co., Ltd., product name), and F2-WS-12 (Furukawa Electric Co., Ltd., product name). Examples of the rolled copper foil include TPC foil (manufactured by JX Nippon Mining & Metal Co., Ltd., trade name), HA foil (manufactured by JX Nippon Mining & Metal Co., Ltd., trade name), HA-V2 foil (manufactured by JX Nippon Mining & Metal Co., Ltd., trade name), and C1100R (manufactured by Sumitomo Mitsui Metal Mine Rolling Co., Ltd., trade name) can be mentioned. From the viewpoint of adhesion to the stretchable resin layer, a copper foil that has been roughened may be used. From the viewpoint of folding resistance, rolled copper foil may be used.

The metal leaf may have a roughened surface formed by the roughening treatment. In this case, the metal foil is usually provided on the stretchable resin layer with the roughened surface in contact with the stretchable resin layer. From the viewpoint of the adhesion between the elastic resin layer and the metal foil, the surface roughness Ra of the roughened surface may be 0.1 to 3 μm or 0.2 to 2.0 μm. The surface roughness Ra of the roughened surface may be 0.3 to 1.5 μm in order to easily form fine wiring.

The surface roughness Ra can be measured under the following conditions using, for example, a surface shape measuring device Wyko NT9100 (manufactured by Veeco).
Measurement conditions Internal lens: 1x External lens: 50x Measurement range: 0.120 x 0.095mm
Measurement depth: 10 μm
Measurement method: Vertical scanning interference method (VSI method)

The thickness of the conductor foil is not particularly limited, but may be 1 to 50 μm. When the thickness of the conductor foil is 1 μm or more, the wiring pattern can be formed more easily. When the thickness of the conductor foil is 50 μm or less, etching and handling are particularly easy.

The conductor foil is provided on one or both sides of the resin layer. By providing the conductor foils on both sides of the resin layer, it is possible to suppress warpage due to heating for curing or the like.

The method of providing the conductor foil is not particularly limited, and for example, there are a method of directly applying the resin composition for forming the resin layer to the metal foil and a method of laminating the resin layer and the conductor foil in the laminated film. ..

(Resin layer)
In the resin layer, for example, a rubber component, a cross-linked compound having an epoxy group, a curing agent, a polyphenylene ether, a phosphorus-based flame retardant, a melamine-based flame retardant, a hindered amine, and, if necessary, other components are dissolved or dispersed in an organic solvent. It can be produced by a method including obtaining a resin varnish and forming a resin varnish on a conductor foil or a carrier film by a method described later.

The organic solvent is not particularly limited, but for example, aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene and p-simene; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; acetone, methyl ethyl ketone and methyl isobutyl ketone. , Cyclohexanone, 4-hydroxy-4-methyl-2-pentanone and other ketones; methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, γ-butyrolactone and the like; Examples thereof include amides such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone. Toluene or N, N-dimethylacetamide may be used from the viewpoint of solubility and boiling point. These organic solvents can be used alone or in combination of two or more. The solid content (component other than the organic solvent) concentration in the resin varnish may be 20 to 80% by mass.

The carrier film is not particularly limited, and for example, polyester such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate; polyolefin such as polyethylene and polypropylene; polycarbonate, polyamide, polyimide, polyamideimide, polyetherimide, and poly. Examples thereof include films such as ether sulfide, polyether sulfone, polyether ketone, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone, and liquid crystal polymer. Among these, from the viewpoint of flexibility and toughness, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polyamide, polyimide, polyamideimide, polyphenylene ether, polyphenylene sulfide, polyallylate, or polysulfone film is used. It may be used as a carrier film.

The thickness of the carrier film is not particularly limited, but may be 3 to 250 μm. When the thickness of the carrier film is 3 μm or more, the film strength is sufficient, and when the thickness of the carrier film is 250 μm or less, sufficient flexibility can be obtained. From the above viewpoint, the thickness may be 5 to 200 μm or 7 to 150 μm. From the viewpoint of improving the peelability from the resin layer, a film obtained by releasing the carrier film with a silicone-based compound, a fluorine-containing compound, or the like may be used, if necessary.

If necessary, a protective film may be attached on the resin layer to form a resin film having a three-layer structure including a carrier film, a resin layer and a protective film.

The protective film is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; and films such as polyolefins such as polyethylene and polypropylene. Among these, from the viewpoint of flexibility and toughness, a polyester film such as polyethylene terephthalate and a polyolefin film such as polyethylene and polypropylene may be used as the protective film. From the viewpoint of improving the peelability from the stretchable resin layer, the protective film may be subjected to a mold release treatment with a silicone-based compound, a fluorine-containing compound, or the like.

The thickness of the protective film may be appropriately changed depending on the desired flexibility, but may be 10 to 250 μm. When the thickness is 10 μm or more, the film strength tends to be sufficient, and when the thickness is 250 μm or less, sufficient flexibility tends to be obtained. From the above viewpoint, the thickness may be 15 to 200 μm or 20 to 150 μm.

Any method may be used as a method for obtaining a laminated board (conductor substrate) having a resin layer and a conductor foil, but a method of applying a varnish of a resin composition for forming a resin layer to a conductor foil. , And a method of laminating a conductor foil on a resin layer formed on a carrier film by a vacuum press, a laminator, or the like. The resin layer can be formed by heating the resin composition to promote a cross-linking reaction (curing reaction) of the cross-linking component.

Any method may be used for laminating the resin layer on the carrier film on the conductor foil, but a roll laminator, a vacuum laminator, a vacuum press, or the like is used. From the viewpoint of production efficiency, it may be molded using a roll laminator or a vacuum laminator.

The thickness of the resin layer is not particularly limited, but may be 5 to 1000 μm, 10 to 500 μm, 20 to 200 μm, or 30 to 100 μm from the viewpoint of the balance between flame retardancy and flexibility of the resin film.

The elastic modulus (tensile elastic modulus) of the resin layer may be 0.1 MPa or more and 1000 MPa or less. When the elastic modulus is 0.1 MPa or more and 1000 MPa or less, the handleability and flexibility as a base material tend to be particularly excellent. From this point of view, the elastic modulus may be 0.3 MPa or more and 100 MPa or less, or 0.5 MPa or more and 50 MPa or less.

The elongation at break of the resin layer may be 100% or more. When the elongation at break is 100% or more, sufficient elasticity tends to be easily obtained. From this viewpoint, the elongation at break may be 150% or more, 200% or more, 300% or more, or 500% or more. The upper limit of the elongation at break is not particularly limited, but is usually about 1000% or less.

The dielectric loss tangent (Df) of the resin layer is 0.004 or less, 0.0035 or less, 0.003 or less, or 0.0025 from the viewpoint of sufficiently reducing the transmission loss of the wiring pattern provided on the resin layer. It may be as follows. The lower limit of the dielectric loss tangent is not particularly limited, but is usually about 0.0005 or more.

The relative permittivity (Dk) of the resin layer may be 3.0 or less, 2.8 or less, or 2.5 or less from the viewpoint of sufficiently reducing the transmission loss of the wiring pattern provided on the resin layer. good.

Although the preferred embodiments of the present disclosure have been described above, these are examples for the purpose of explaining the present invention, and the scope of the present invention is not limited to these embodiments. The present invention can be carried out in various embodiments different from the above embodiments without departing from the gist thereof.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

[Example 1]
Maleic anhydride-modified hydrogenated styrene ethylene butadiene rubber (manufactured by KRATON Co., Ltd., trade name "FG1924", styrene ratio: 1.3%) 80 parts by mass (blending amount of non-volatile content), dicyclopentadiene type epoxy resin in polybin (Manufactured by DIC Co., Ltd., trade name "EPICLON HP7200H") 10.9 parts by mass (blending amount of non-volatile content), ester-based curing agent (manufactured by DIC Co., Ltd., trade name "HPC-8150") 9.1 parts by mass ( The amount of the non-volatile content) and 400 parts by mass of toluene were added and mixed to obtain a base resin having a non-volatile content of 25% by mass. Next, the base resin contains 15 parts by mass of polyphenylene ether (PPE, manufactured by Asahi Kasei Co., Ltd., trade name "S202A"), 20 parts by mass of a phosphorus flame retardant (manufactured by Clarant Chemicals Co., Ltd., trade name "OP935"), and melamine-based refractory. 20 parts by mass of flame retardant (melamine cyanurate, manufactured by Sakai Chemical Industry Co., Ltd., trade name "STABIACE MC-20S"), 5 parts by mass of hindered amine (manufactured by BASF Japan Co., Ltd., trade name "Flamestab NOR 116FF"), and 1- Add 3 parts by mass of benzyl-2-methylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name "1B2MZ"), mix using a rotation revolving mixer (manufactured by Shinky Co., Ltd., AR-100), and resin varnish. Was produced.

[Comparative Examples 1 to 8]
A resin varnish was prepared in the same manner as in Example 1 except that the addition amounts of PPE, phosphorus-based flame retardant, melamine-based flame retardant and hindered amine were changed to the amounts (parts by mass) shown in Table 1.

[evaluation]
(Preparation of resin film)
A release-treated polyethylene terephthalate (PET) film (manufactured by Teijin Film Solution Co., Ltd., trade name "Purex A31", thickness 25 μm) was prepared as a carrier film. The above resin varnish was applied onto the release-treated surface of this PET film using a knife coater (manufactured by Yasui Seiki Co., Ltd., trade name "SNC-350"). The coating film was dried by heating at 80 ° C. for 20 minutes in a dryer (manufactured by Futaba Kagaku Co., Ltd., trade name “MSO-80TPS”) to form a resin layer having a thickness of 80 μm. The same release-treated PET film as the carrier film was attached to the formed resin layer as a protective film with the release-treated surface facing the resin layer side to obtain a resin film.

(Combustion test)
After peeling off the carrier film and protective film from the resin film, the resin layer is cured and burned by heating at 180 ° C. for 60 minutes in a dryer (manufactured by Futaba Kagaku Co., Ltd., trade name "MSO-80TPS"). A test sample was prepared. The UL94V test was performed on the sample for the combustion test. The results are shown in Table 1.

Claims (5)

A resin composition containing a rubber component, a cross-linking component having an epoxy group, a curing agent, a polyphenylene ether, a phosphorus-based flame retardant, a melamine-based flame retardant, and a hindered amine. The resin composition according to claim 1, wherein the phosphorus-based flame retardant contains a phosphinic acid metal salt or an aromatic condensed phosphoric acid ester. The resin composition according to claim 1 or 2, wherein the melamine-based flame retardant contains melamine cyanurate. The rubber components are acrylic rubber, isoprene rubber, butyl rubber, styrene butadiene rubber, butadiene rubber, acrylonitrile butadiene rubber, silicone rubber, urethane rubber, chloroprene rubber, ethylene propylene rubber, fluororubber, sulfide rubber, epichlorohydrin rubber, and chlorinated butyl rubber. The resin composition according to any one of claims 1 to 3, which comprises at least one rubber selected from the group consisting of. It has a resin layer and a conductor foil provided on the resin layer.
A conductor substrate in which the resin layer contains a cured product of the resin composition according to any one of claims 1 to 4.