Resin composition, and coverlay film, adhesive sheet, resin-coated metal foil, metal-clad laminate, or printed wiring board using the same

Abstract

To provide a coverlay and an adhesive sheet which are excellent in resin flow characteristics in secondary processing, and a circuit board using the same.SOLUTION: A resin composition is used in an adhesive layer of a laminated substrate, wherein when a laminate is formed by sandwiching a sheet-shaped completely-cured material with a thickness of 25 μm with a polyimide film with a thickness of 125 μm having the same sheet shape from both surfaces, the laminate is punched and a disk-shaped test sample is prepared, the test sample is subjected to hot press from a thickness direction under the conditions of 160°C, 2 MPa and 30 minutes, an average value of maximum lengths (specifically, secondary resin flow amount) of a resin flowing out to the outside from the outer periphery of the test sample is less than 0.15 mm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, and to a coverlay film, an adhesive sheet, a resin-coated metal foil, a metal-clad laminate, or a printed wiring board using the same. [Background technology]

[0002] In recent years, flexible printed circuit boards (FPCs) have come into widespread use as electronic devices become smaller and denser. Typically, FPCs are made from flexible copper-clad laminates (FCCLs), which are made by laminating copper foil with an insulating film such as polyimide. The copper foil of the FCCL is etched to form circuits and wiring, and then the circuit is protected with a coverlay film (CL), which is a laminate of a flexible insulating film and an adhesive layer. In some cases, a multilayer structure is created by laminating a flexible adhesive sheet (BS) and another FCCL onto the FCCL with the circuit formed on it.

[0003] Adhesives used in CL and BS must have excellent adhesion to the insulating layer and copper foil, heat resistance to withstand the mounting process, long-term insulation reliability, and excellent processability during manufacturing. In particular, the flow characteristics of the adhesive when bonding and curing by hot pressing (resin flow) are extremely important, as they affect the connection reliability of openings such as terminals and land pads.

[0004] Various methods have been proposed to satisfy these characteristics. For example, Patent Document 1 proposes controlling the blending amounts of carboxylated ethylene-acrylic rubber and phenolic hydroxyl group-containing aromatic polyamide-carboxylated nitrile butadiene rubber copolymer as elastomers. Patent Document 2 proposes the use of phosphorus-containing phenoxy resin. Patent Document 3 proposes the use of polyimide siloxane resin. Patent Document 4 proposes the use of imide oligomer. Furthermore, Patent Document 5 proposes laminating two or more layers of adhesives with different resin flow properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4738859 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-219590 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-224428 [Patent Document 4] Japanese Patent Application Publication No. 2019-81893 [Patent Document 5] Patent No. 4855291 Summary of the Invention [Problem to be solved by the invention]

[0006] However, while the techniques described in Patent Documents 1 to 5 can control the resin flow during the hot pressing (primary processing) of CL and BS, no consideration has been given to the resin flow during the subsequent hot pressing (secondary processing) such as reinforcing plate processing and shielding film processing.

[0007] If resin flow occurs in the CL or BS that has already been laminated during secondary processing, problems such as insulating the openings of the terminals, land pads, etc. by covering them with adhesive, or the adhesive that flows out from the edge of the board may come off and cause process contamination, etc.

[0008] Therefore, the purpose of this patent is to provide a coverlay, an adhesive sheet, and a circuit board using the same that have excellent resin flow properties during secondary processing. [Means for solving the problem]

[0009] As a result of intensive research to solve the above problems, the present inventors discovered that by making the cured resin composition satisfy specific viscoelastic properties, it is possible to obtain an adhesive layer with excellent resin flow properties during secondary processing, and thus completed the present invention.

[0010] That is, the present invention is as follows. [1] A resin composition used in the adhesive layer of a laminated substrate, which is prepared by sandwiching a fully cured, 25 μm thick sheet of the composition between 125 μm thick polyimide films of the same shape on both sides to form a laminate, punching out this laminate to create a disk-shaped test specimen, and hot-pressing the test specimen in the thickness direction under conditions of 160°C, 2 MPa, and 30 minutes. The average maximum length of the resin that flows out from the outer periphery of the test specimen (i.e., the amount of secondary resin flow) is less than 0.15 mm. [2] A resin composition used in an adhesive layer of a laminated substrate, in which, in a dynamic viscoelastic measurement at 180°C in a fully cured state, the loss tangent (tanδ) value 5 minutes after the start of measurement is T1, the loss tangent value 10 minutes after the start of measurement is T2, and the loss tangent value 15 minutes after the start of measurement is T3, all of T1, T2, and T3 are 0.2 or less. [3] A composition containing a modified polypropylene resin (A) and an epoxy resin (B), The resin composition according to [1] or [2], wherein the content of the modified polypropylene resin (A) is 50% by mass or more. [4] The resin composition according to any one of [1] to [3], which has a dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less at a measurement frequency of 10 GHz in a completely cured state. [5] The resin composition according to [3], wherein the content of the epoxy resin (B) is 1 part by mass or more and 20% by mass or less. [6] The resin composition according to [3], wherein the modified polypropylene resin (A) is a resin modified with at least one carboxylic acid compound or a derivative thereof, and has an acid value of 5 mgKOH / g or more. [7] The resin composition according to any one of [1] to [6], wherein one or more curing accelerators selected from a tertiary amine curing accelerator, a tertiary amine salt curing accelerator, and an imidazole curing accelerator are not added. [8] The resin composition according to any one of [1] to [7], which is used for bonding organic resin substrates together, metal substrates together, or an organic resin substrate and a metal substrate. [9] The resin composition according to any one of [1] to [8], wherein the resin composition is in a semi-cured state and is formed into a sheet shape of 25 μm in thickness, and the laminate is laminated on a polyimide sheet of 50 μm in thickness, and an opening of 1.0 mm in diameter is formed in the thickness direction of the laminate. The laminate is used as a test specimen, and the test specimen is laminated on an electrolytic copper foil of 35 μm in thickness with the polyimide sheet facing outward, and after hot pressing under conditions of 180°C and 2.7 MPa for 60 minutes, the average maximum length of the resin that flows out to the inside of the opening is less than 0.2 mm.

[10] A laminate comprising an adhesive layer formed using the resin composition according to any one of [1] to [9] above, and a substrate in contact with at least one surface of the adhesive layer, wherein the substrate is any one of a resin substrate, a release resin substrate, a paper substrate, a release paper substrate, and a metal substrate.

[11] A coverlay film, an adhesive sheet, a resin-coated metal foil, or a metal-clad laminate comprising the laminate according to

[10] .

[12] A printed wiring board comprising the laminate according to

[10] or the coverlay film, adhesive sheet, resin-coated metal foil, or metal-clad laminate according to

[11] .

[13] A semiconductor device comprising the printed wiring board according to

[12] . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a coverlay film, an adhesive sheet, a resin-coated metal foil, a metal-clad laminate, or a printed wiring board that has excellent resin flow properties during hot pressing (secondary processing) such as reinforcing plate processing or shielding film processing, as well as a semiconductor device equipped with the above-mentioned printed wiring board. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the present invention will be described in detail with reference to exemplary embodiments, although the present invention is not limited thereto.

[0013] 1.Resin composition The resin composition according to this embodiment comprises a modified polypropylene resin (A) and an epoxy resin (B). The components of the resin composition will be described below. In this embodiment, the resin composition is a slurry prepared by dissolving or suspending the above-mentioned components in a solvent such as an organic solvent, which is then applied to a substrate such as release paper and dried (before heating).

[0014] <Modified polypropylene resin (A)> The modified polypropylene resin used in the present invention is a resin obtained by modifying a polypropylene resin with at least one compound containing an organic functional group or a derivative thereof. Specific examples of the organic functional group include a carboxy group, an amino group, a hydroxy group, an epoxy group, a mercapto group, a vinyl group, an acryloyl group, and a methacrylic group. Among these, a carboxy group is preferred. The polypropylene resin is a polymer containing propylene as a monomer, and includes a propylene homopolymer or a copolymer with other monomers, as well as hydrogenated or halized versions of the resulting polymer. Copolymers with olefinic monomers and hydrogenated versions thereof are particularly preferred.

[0015] Examples of compounds containing a carboxy group or a derivative thereof include α,β-unsaturated carboxylic acids such as maleic acid, itaconic acid, and citraconic acid, as well as their acid anhydrides. Among these, acid anhydrides are preferred, with maleic anhydride being more preferred. These may be used alone or in combination of two or more. Modification methods include adding a carboxylic acid compound or its derivative as a monomer during polymerization of a modified polypropylene resin to form a copolymer, and grafting a carboxylic acid compound or its derivative onto an unmodified polypropylene resin.

[0016] From the viewpoints of heat resistance, adhesion to organic resin substrates and metal substrates, and resin flow characteristics, the acid value of the modified polypropylene resin is preferably 5 mgKOH / g or more, and more preferably 10 mgKOH / g or more and 50 mgKOH / g or less.

[0017] The weight-average molecular weight (Mw) of the modified polypropylene resin is not particularly limited, but is preferably in the range of 20,000 to 180,000. A weight-average molecular weight of 20,000 or more is preferable because it provides strong cohesive strength and excellent adhesion. It also improves resin flow characteristics during the hot press (primary processing) process, which bonds and cures the adhesive to the adherend. A weight-average molecular weight of 180,000 or less is also preferable because it increases fluidity, improves circuit embedding during hot press, and improves adhesion due to improved wettability. It also improves solubility in organic solvents, preventing deterioration in workability when forming a varnish.

[0018] Such modified polypropylene resins are commercially available, and among them, acid-modified polypropylene resins include the "ADMER (registered trademark)" series and "UNISTOLE (registered trademark)" series manufactured by Mitsui Chemicals, Inc., "Auroren (registered trademark)" series "150A", "200S", "200T", "350S", "AE201", and "AE301" manufactured by Nippon Paper Industries Co., Ltd., "Fusabond (registered trademark)" series "P353", "P613", "E226", and "A560" manufactured by Dow Chemical Co., Ltd., "UMEX (registered trademark)" series manufactured by Sanyo Chemical Industries, Ltd., P type of the "MODIC (registered trademark)" series manufactured by Mitsubishi Chemical Corporation, and "M-100", "M-300", "M-310", "PMA H1000A", "PMA H1100A", and "PMA Examples of usable products include "H3000A," "PMA-T," "PMA-F2," and "PMA-L"; "TD-15B," "NS-2002," and "NS-2104" from the "Hardlen (registered trademark)" series; "MS-003K," "MS-003JD," and "SW-2420" from the "Hi-Loss-X (registered trademark)" series manufactured by Seiko PMC Corporation; "PL-2051," "PL-2291," "QL-2251," "RL-2027," and "RL-2047" from the "Rike-Aid (registered trademark)" series manufactured by Riken Vitamin Co., Ltd.; and "MG-250P," "MG-400P," and "MG-670P" from the "Rike-Aid (registered trademark)" series manufactured by Riken Vitamin Co., Ltd.

[0019] The content of the modified polypropylene resin (A) in the resin composition of the present invention is preferably 50 parts by mass or more per 100 parts by mass of the solid matter (solid content) remaining after complete evaporation of the solvent from the resin composition (since the resin composition according to this embodiment is substantially solvent-free, the content in the resin composition can be said to be 50% by mass or more). More preferably, it is 65 parts by mass or more per 100 parts by mass of the solid content. A content of the modified polypropylene resin (A) of 50 parts by mass or more per 100 parts by mass of the solid content improves the resin flow characteristics during hot pressing (secondary processing) such as reinforcing plate processing and shielding film processing, thereby minimizing resin outflow from openings and substrate edges. The upper limit of the content of the modified polypropylene resin (A) per 100 parts by mass of the solid content of the resin composition is preferably 99 parts by mass or less, and may be 95 parts by mass or less, or may be 90 parts by mass or less.

[0020] <Epoxy resin (B)> The epoxy resin reacts with the carboxyl groups and acid anhydride groups in the modified polypropylene resin (A) to form a three-dimensional crosslinked structure, enabling it to exhibit excellent adhesion to the substrate, high heat resistance that can withstand the mounting process, and long-term insulation reliability.

[0021] The epoxy resin (B) used in the present invention is not particularly limited as long as it has two or more epoxy groups in the molecule. Specific examples include biphenyl-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, novolac-type epoxy resins, trisphenol-type epoxy resins, alicyclic epoxy resins, dicyclopentadiene-type epoxy resins, aliphatic epoxy resins, glycidylamine-type epoxy resins, glycidylester-type epoxy resins, and heterocyclic epoxy resins. These may be used alone or in combination of two or more.

[0022] Such epoxy resins are commercially available, and include "HP-4032," "HP-4032H," and "HP-4032D" (naphthalene-type epoxy resins), "HP-4770" (naphthalene-type bifunctional epoxy resins), "HP-4700," "HP-4710" (naphthalene-type tetrafunctional epoxy resins), "HP-5000," and "HP-9900" (naphthalene-skeleton-modified multifunctional epoxy resins), "N-690" (cresol novolac-type epoxy resins), "N-695" (cresol novolac-type epoxy resins), "HP-7200," "HP-7200L," "HP-7200H," "HP-7200HH," and "HP" manufactured by DIC Corporation. -7200HHH" (dicyclopentadiene type epoxy resin), "EXA-1514" (bisphenol S type epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (naphthylene ether type epoxy resin), Nippon Kayaku Co., Ltd.'s "EPPN-502H" (trisphenol type epoxy resin), "NC-7000L" (naphthol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (biphenyl type epoxy resin), Nippon Steel & Sumikin Chemical Co., Ltd.'s "ESN4 Examples of epoxy resins that can be used include "75V" (naphthalene-type epoxy resin), "ESN485" (naphthol novolac-type epoxy resin), "YX4000H" and "YL6121" (biphenyl-type epoxy resin), "YX4000HK" (bixylenol-type epoxy resin), and "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd., "YL7800" (fluorene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1010" (solid bisphenol A-type epoxy resin), and "jER1031S" (tetraphenylethane-type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "Epolead PB-3600" and "Epolead PB-4700" (epoxidized polybutadiene) manufactured by Daicel Corporation, and "jER YX7760" (fluorine-containing epoxy resin) manufactured by Mitsubishi Chemical Corporation.

[0023] From the viewpoint of dielectric properties, the epoxy resin (B) is preferably an epoxy resin having a saturated hydrocarbon skeleton, specifically, an alicyclic epoxy resin, a dicyclopentadiene-type epoxy resin, or an aliphatic epoxy resin. It is more preferable to use a non-alicyclic epoxy resin such as an epoxidized polyolefin.

[0024] The content of the epoxy resin (B) in the resin composition of the present invention is preferably 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the solid content. More preferably, it is 5 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the solid content. By setting the content of the epoxy resin (B) within this range, it is possible to maintain a sufficient crosslink density and prevent a decrease in adhesion and heat resistance, which is preferable. It is also possible to prevent an effect on the dielectric properties.

[0025] The resin composition according to this embodiment is composed of the modified polypropylene resin (A) and the epoxy resin (B) described above. Therefore, the components described below are not essential components, but can be added as appropriate depending on the application.

[0026] <Curing accelerator> Curing accelerators are compounds that catalyze and accelerate the reaction between modified polypropylene resins and epoxy resins. Specific examples include tertiary amine-based curing accelerators, tertiary amine salt-based curing accelerators, and imidazole-based curing accelerators. These compounds act as nucleophiles for epoxy groups, generating zwitterionic active species to accelerate the curing reaction. They have long been used to control reactivity in epoxy resin compositions, and many examples have been reported in which they improve cured properties such as adhesion and heat resistance.

[0027] However, in the reaction between modified polypropylene resin and epoxy resin, a sufficient reaction rate can be achieved even without the presence of a curing accelerator. Therefore, a curing accelerator is not an essential component, but may be added if it is necessary to further improve the reaction rate. However, adding a curing accelerator in excess of a predetermined amount may shorten the pot life when the resin composition described in this embodiment is made into a varnish or slurry, or may shorten the product life when a semi-cured (B-stage) adhesive layer is formed using the resin composition in the form of a coverlay film, adhesive sheet, resin-coated metal foil, etc. Therefore, in the present invention, it is preferable to limit the content of the curing accelerator to an amount that would shorten the pot life or product life, and it is more preferable to not add a curing accelerator.

[0028] <(Poly)carbodiimide resin> (Poly)carbodiimide resin is a general term for polymers containing carbodiimide bonds. (Poly)carbodiimide resins are known to improve adhesion by reacting the carbodiimide groups with functional groups such as hydroxyl, amino, and carboxyl groups in the base resin, enhancing the interaction between the resin composition and the substrate.

[0029] Such (poly)carbodiimide resins are commercially available, and examples thereof include the "Carbodilite (registered trademark)" series manufactured by Nisshinbo Chemical Inc.

[0030] A common method for producing a (poly)carbodiimide resin is to polycondense a diisocyanate compound or a polyfunctional isocyanate compound in the presence of a catalyst. Due to the nature of this production method, a few percent of unreacted isocyanate groups often remain. Isocyanate groups are highly reactive and can react with modified polypropylene resins or epoxy resins, which can result in a reduction in lifespan, similar to the case of curing accelerators. Therefore, in this embodiment, the content of the (poly)carbodiimide resin is preferably below the amount that would reduce the product lifespan, and it is more preferable to not add a (poly)carbodiimide resin. The amount that causes a reduction in product life is preferably more than 0 parts by mass and not more than 0.4 parts by mass, more preferably not more than 0.3 parts by mass, and particularly preferably not more than 0.2 parts by mass, per 100 parts by mass of the solid content.

[0031] In addition to the above, the resin composition of the present invention may contain thermoplastic resins, tackifiers, flame retardants, curing agents, coupling agents, heat aging inhibitors, leveling agents, antifoaming agents, fillers, pigments, organic solvents, etc., within a range that does not affect the functions of the resin composition, for example, the total amount of other components excluding the modified polypropylene resin and epoxy resin may be 49 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, or 1 part by mass or less, per 100 parts by mass of the resin composition.

[0032] <Thermoplastic resin> Examples of thermoplastic resins other than the modified polypropylene resin (A) include phenoxy resins, polyamide resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, polyacetal resins, and polyolefin resins. These thermoplastic resins may be unmodified or functionally modified. They may be used alone or in combination of two or more. Polyolefin resins are particularly suitable for addition to the resin composition of the present invention because of their low dielectric properties and excellent adhesion to substrates.

[0033] Such polyolefin resins are commercially available, and examples thereof include the "Tufprene (registered trademark)" series and "Asaprene (registered trademark) T" series manufactured by Asahi Kasei Corporation, the "Kraton (registered trademark) D SBS" series (SBS resin) manufactured by Kraton Polymer Japan, Ltd., the "Tuftec (registered trademark) H" series and "Tuftec (registered trademark) P" series manufactured by Asahi Kasei Corporation, the "Kraton (registered trademark) A" series, "Kraton (registered trademark) E" series and "Kraton (registered trademark) G" series (SEBS resin) manufactured by Kraton Polymer Japan, Ltd., the "Tuftec (registered trademark) M" series manufactured by Asahi Kasei Corporation, and the "Kraton (registered trademark) FG" series (acid-modified SEBS resin) manufactured by Kraton Polymer Japan, Ltd.

[0034] <Tackifier> Examples of the tackifier include coumarone-indene resins, terpene resins, terpene-phenol resins, rosin resins, pt-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, petroleum-based hydrocarbon resins, hydrogenated hydrocarbon resins, turpentine-based resins, etc. These tackifiers may be used alone or in combination of two or more.

[0035] <Flame retardant> The flame retardant may be either an organic flame retardant or an inorganic flame retardant. Examples of organic flame retardants include phosphorus-based flame retardants such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium amido phosphate, ammonium amido polyphosphate, carbamate phosphate, carbamate polyphosphate, aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, titanium tetrakisdiethylphosphinate, titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate, and titanium tetrakisdiphenylphosphinate; nitrogen-based flame retardants such as triazine-based compounds such as melamine, melam, and melamine cyanurate, cyanuric acid compounds, isocyanuric acid compounds, triazole-based compounds, tetrazole compounds, diazo compounds, and urea; and silicon-based flame retardants such as silicone compounds and silane compounds. Examples of inorganic flame retardants include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, and calcium hydroxide; metal oxides such as tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, and nickel oxide; zinc carbonate, magnesium carbonate, barium carbonate, zinc borate, and hydrated glass. Two or more of these flame retardants can be used in combination.

[0036] <Curing agent> Examples of the curing agent include, but are not limited to, amine-based curing agents and acid anhydride-based curing agents. Examples of the amine-based curing agent include melamine resins such as methylated melamine resin, butylated melamine resin, and benzoguanamine resin, dicyandiamide, and 4,4'-diphenyldiaminosulfone. Examples of the acid anhydride include aromatic acid anhydrides and aliphatic acid anhydrides. These curing agents may be used alone or in combination of two or more.

[0037] <Coupling agent> Examples of the coupling agent include silane-based coupling agents such as vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatepropyltriethoxysilane, and imidazolesilane; titanate-based coupling agents; aluminate-based coupling agents; and zirconium-based coupling agents. These may be used alone or in combination of two or more.

[0038] <Anti-aging agent> Examples of the heat aging inhibitor include phenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate]; sulfur-based antioxidants such as dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-dithiopropionate; and phosphorus-based antioxidants such as trisnonylphenyl phosphite, tris(2,4-di-tert-butylphenyl)phosphite. These may be used alone or in combination of two or more.

[0039] <Filler> Examples of the filler include particles of inorganic compounds such as titanium oxide, aluminum oxide, zinc oxide, carbon black, silica, talc, copper, and silver; particles of organic compounds such as fluorine-based polymers (polytetrafluoroethylene, perfluoroalkoxyalkane, etc.) and various elastomers; etc. These may be used alone or in combination of two or more.

[0040] <Organic solvents> The resin composition according to this embodiment may further contain an organic solvent. The organic solvent used in the present invention is not particularly limited as long as it can uniformly dissolve or disperse the modified polypropylene resin (A) and the epoxy resin (B). Specific examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, heptane, octane, and decane; alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane, and ethylcyclohexane; halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform; alcoholic solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, and the like. Examples of suitable solvents include ketone solvents such as isophorone and acetophenone, cellosolves such as methyl cellosolve and ethyl cellosolve, ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate, and glycol ether solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso-butyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether. These may be used alone or in combination of two or more. Organic solvents are typically used from the viewpoint of workability. From the viewpoint of solubility, low-polarity solvents such as aromatic hydrocarbons and aliphatic hydrocarbons are particularly preferred.

[0041] When forming the resin composition according to this embodiment, it is preferable to prepare a solution (varnish) in which the above-mentioned components are uniformly dissolved or a slurry in which the components are dispersed, and then uniformly apply this solution (varnish) or slurry onto a substrate. Therefore, from the viewpoint of workability, the content of the organic solvent in the solution (varnish) or slurry is preferably 3 to 80 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the solid content. If the content of the organic solvent per 100 parts by mass of the solid content is 80% by mass or less, the viscosity of the solution (varnish) or slurry becomes appropriate, making it easy to apply the solution (varnish) or slurry uniformly. As described above, the resin composition according to this embodiment is obtained by applying and drying the solution (varnish) or slurry, and therefore almost all of the organic solvent volatilizes during drying. As a result, the resin composition can be substantially free of organic solvent, but the resin composition may also contain a small amount of the organic solvent contained in the solution (varnish) or slurry.

[0042] 2.Cured product By thermally curing the resin composition of the present invention, a cured product that serves as, for example, an insulating layer or adhesive layer of a laminated substrate can be obtained. In this embodiment, the thermal curing includes the following two stages. When the resin composition is heated, first a covalent bond forms between the modified polypropylene and the epoxy resin in the resin composition, forming a two-dimensional crosslink (molecular chain extension), and a semi-cured (B-stage) cured product is obtained. By further heating this semi-cured product, further covalent bonds are formed between the modified polypropylene and the epoxy resin, and between the epoxy resins themselves, forming three-dimensional crosslinks (inter-chain crosslinks), resulting in the formation of a crosslinked structure and a completely cured product (C-stage). The B-stage and C-stage can be distinguished, for example, by the solubility when immersed in an organic solvent. The conditions for this thermal curing are not particularly limited, and for example, conditions that are normally employed when forming an insulating layer for a printed wiring board may be used.

[0043] For example, the curing conditions for the resin composition can be such that the curing temperature is in the range of 80°C to 240°C, preferably in the range of 120°C to 220°C, and more preferably in the range of 150°C to 200°C, and the curing time is in the range of 1 minute to 240 minutes, preferably in the range of 1 minute to 180 minutes, and more preferably in the range of 1 minute to 120 minutes.

[0044] In addition, hot pressing is usually used as a method for forming an insulating layer of a printed wiring board. The pressing pressure conditions are not particularly limited, and commonly used conditions may be used, for example, in the range of 0.5 MPa to 5.0 MPa.

[0045] In a C-stage cured product obtained by thermally curing the resin composition according to this embodiment, when dynamic viscoelasticity is measured at 180°C, the loss tangent (tanδ) value 5 minutes after the start of measurement is T1, the loss tangent value 10 minutes after the start of measurement is T2, and the loss tangent value 15 minutes after the start of measurement is T3. T1, T2, and T3 are all 0.2 or less.

[0046] The loss tangent (tanδ) in dynamic viscoelasticity measurements is also called the loss factor, and is expressed as the ratio (G" / G') of the storage modulus (G') to the loss modulus (G"). During measurement, of the energy generated by external forces and strain on an object, the component that is stored inside the object is the storage modulus, which is an index of the object's elasticity. The component that diffuses to the outside is the loss modulus, which is an index of the object's viscosity. In other words, as the loss modulus increases, the loss tangent increases, and conversely, as the loss modulus decreases, the loss tangent decreases.

[0047] The smaller the loss tangent, the closer the object is to a perfect elastic body. In other words, the less likely it is to flow when an external force is applied. According to the resin composition of this embodiment, if the cured product satisfies the specific loss tangent described above, the resin flow during the hot pressing (secondary processing) such as reinforcing plate processing or shielding film processing that follows the hot pressing (primary processing) of CL or BS can be suppressed to a range of less than 0.15 mm.

[0048] Furthermore, the cured product obtained by thermally curing the resin composition according to the embodiment preferably has a dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less at a measurement frequency of 10 GHz. It has been known that as the transmission signal of a substrate increases in frequency, the influence of signal degradation (attenuation, delay, etc.) due to dielectric loss increases. That is, according to the present embodiment, by having the cured product of the resin composition satisfy the above-mentioned specific dielectric constant and dielectric loss tangent, excellent signal transmission characteristics can be achieved even in high-frequency substrates.

[0049] 3.Laminate The laminate of the present invention comprises an adhesive layer that is a cured product of the resin composition described above, and a substrate in contact with at least one side of the adhesive layer, wherein the substrate is any of an organic film, an organic film with a release treatment, release paper, and metal foil. The resin composition of the present invention is uniformly dissolved and dispersed (varnished) in a solvent according to a standard method, and then applied to a substrate and dried to obtain a laminate having an adhesive layer. Typically, it is often produced in a semi-cured (B-stage) state in which only a portion is cured. By laminating the obtained laminate with another substrate, a laminate having substrates on both sides of the adhesive layer can be obtained. The laminate may also be in a fully cured (C-stage) state by heating.

[0050] The substrate used in the laminate according to the present invention is not particularly limited as long as it can form an adhesive layer by applying and drying the resin composition of the present invention, and examples thereof include a resin substrate, a release resin substrate, a paper substrate, a release paper substrate, and a metal substrate.

[0051] <Resin substrate> A resin substrate can be used for the purpose of improving electrical insulation and mechanical strength. Examples of the resin substrate include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluorine-based resin. A film-like resin is preferred.

[0052] <Release resin substrate> A release resin substrate can be used to transfer the adhesive layer to another substrate. Examples of the release resin substrate include various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, and propylene-α-olefin copolymer, as well as films such as polyethylene terephthalate coated with a silicone-based, fluorine-based, or alkyd-based release agent.

[0053] <Paper base material> A paper substrate can be used for the purpose of improving electrical insulation and mechanical strength. Examples of paper substrates include fine paper, kraft paper, roll paper, and glassine paper. Examples of composite materials include glass epoxy.

[0054] <Release paper base material> A release paper substrate can be used to transfer the adhesive layer to another substrate. Examples of the release paper substrate include those in which coating layers of a filler such as clay, polyethylene, or polypropylene are provided on both sides of the above-mentioned paper substrate, and a release agent such as a silicone-based, fluorine-based, or alkyd-based agent is further applied on each coating layer.

[0055] <Metal base material> The metal substrate can be any conventionally known conductive material that can be used for circuit boards. Examples of materials include various metals such as SUS, copper, aluminum, iron, steel, zinc, and nickel, as well as their alloys, plated products, and metals treated with other metals such as zinc or chromium compounds. Metal foil is preferred, and copper foil is more preferred. The thickness of the metal foil is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 10 μm or more. It is also preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit. On the other hand, if the thickness is too thick, processing efficiency during circuit fabrication may decrease. Metal foil is usually provided in a roll form. The form of the metal foil used in producing the printed wiring board of the present invention is not particularly limited. When a ribbon-shaped metal foil is used, its length is not particularly limited. Its width is also not particularly limited, but is preferably about 250 mm to 1000 mm.

[0056] 4. Coverlay film The coverlay film (CL) of the present invention is a laminate having an adhesive layer in a B-stage state formed from the resin composition described above on a substrate having excellent insulation properties, and making it difficult to disassemble the substrate and adhesive layer. The resin substrate described above can be used as the substrate having excellent insulation properties. In addition, to protect the adhesive layer, a protective layer can be laminated on the side of the adhesive layer that is not in contact with the substrate having excellent insulation properties. The protective layer can be a release substrate (the release resin substrate described above or the release paper substrate described above). Laminating a protective layer on the adhesive layer allows winding without causing offset onto the substrate, resulting in excellent operability, and the adhesive layer is protected, resulting in excellent storage stability and ease of use.

[0057] After peeling off the protective layer from the coverlay film obtained by the present invention, the adhesive layer is brought into surface contact with any circuit board and hot pressed to function as an insulating coating material.

[0058] 5. Adhesive sheet The adhesive sheet (bonding sheet, BS) in the present invention is a laminate having an adhesive layer in a B-stage state formed from the resin composition described above on a release substrate, which allows the adhesive layer to be separated. To protect the adhesive layer, release substrates can be laminated on both sides of the adhesive layer. The release substrate acts as a protective layer for the adhesive layer, allowing it to be wound up without causing offset onto the substrate, resulting in excellent operability, and since the adhesive layer is protected, it has excellent storage properties and is easy to use.

[0059] The adhesive sheet obtained by the present invention functions as an interlayer adhesive by peeling off one of the release substrates, transferring the adhesive layer to any substrate, peeling off the other release substrate, and surface-adhering the sheet to any substrate, followed by hot pressing.

[0060] 6. Metal foil with resin The resin-coated metal foil of the present invention is a laminate having an adhesive layer in a B-stage state formed from the resin composition on the metal substrate, making it difficult to disassemble the substrate and adhesive layer. To protect the adhesive layer, a protective layer can be laminated on the side that is not in contact with the metal substrate. A release substrate can be used as the protective layer. Laminating a protective layer on the adhesive layer allows for winding without causing offset onto the substrate, resulting in excellent operability. Furthermore, the adhesive layer is protected, resulting in excellent storage stability and ease of use.

[0061] After peeling off the protective layer, the resin-coated metal foil obtained by the present invention functions as a circuit-forming material by bringing the adhesive layer into surface contact with any substrate or circuit board and hot pressing.

[0062] 7.Metal clad laminate The metal-clad laminate of the present invention is a laminate in which a metal substrate and a resin substrate are bonded together via an adhesive layer formed from the resin composition described above. The adhesive layer is applied to one substrate, dried, bonded to the other substrate, and then completely cured using an oven or the like. Alternatively, the adhesive layer and the metal substrate may be laminated on both sides of the resin substrate.

[0063] The metal-clad laminate obtained by the present invention functions, for example, as a circuit-forming material for printed wiring boards.

[0064] 8. Printed wiring boards The printed wiring board of the present invention includes, as a component, a laminate formed from a metal foil forming a conductor circuit and a resin substrate. The printed wiring board is manufactured by a conventionally known method such as a subtractive method using the above-mentioned metal-clad laminate. The term "printed wiring board" collectively refers to so-called flexible circuit boards (FPCs), flat cables, circuit boards for tape automated bonding (TAB), etc., in which a conductor circuit formed from metal foil is partially or entirely covered with a cover film, screen printing ink, etc., as necessary.

[0065] The printed wiring board of the present invention can have any laminated structure that can be used as a printed wiring board. For example, it can be a printed wiring board consisting of four layers: a resin substrate layer, a metal foil layer, an adhesive layer, and a cover film layer. Alternatively, it can be a printed wiring board consisting of five layers: a resin substrate layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

[0066] Furthermore, if necessary, two or more of the above printed wiring boards may be stacked.

[0067] The adhesive layer formed using the resin composition of the present invention can be suitably used as a coverlay film, adhesive sheet, resin-coated metal foil, or metal-clad laminate as a material for printed wiring boards, particularly as a material for printed wiring boards for high-frequency signal transmission.

[0068] 9. Semiconductor Devices The semiconductor device of the present invention includes the printed wiring board of the present invention described above. The semiconductor device of the present invention can be manufactured using the printed wiring board of the present invention.

[0069] Examples of semiconductor devices include various semiconductor devices used in electrical appliances (for example, computers, mobile phones, digital cameras, and televisions) and vehicles (for example, motorcycles, automobiles, trains, ships, and aircraft).

[0070] The semiconductor device of the present invention can be manufactured by mounting a component (semiconductor chip) on a conductive portion of a printed wiring board. The "conductive portion" refers to a portion of the printed wiring board that transmits an electrical signal, and the portion may be either on the surface or embedded. The semiconductor chip is not particularly limited as long as it is an electrical circuit element made of a semiconductor material.

[0071] The method for mounting a semiconductor chip when manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip functions effectively, but specific examples include wire bonding mounting, flip chip mounting, bumpless buildup layer (BBUL) mounting, anisotropic conductive film (ACF) mounting, non-conductive film (NCF) mounting, etc. Here, the "bumpless buildup layer (BBUL) mounting method" refers to "a mounting method in which a semiconductor chip is directly embedded in a recess in a printed wiring board and the semiconductor chip is connected to the wiring on the printed wiring board." [Example]

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following description, "parts" and "%" mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0073] [Physical property evaluation method] (1) Crocodile Spot Life In the present invention, the term "varnish spot life" refers to the storage stability at room temperature of a solution (varnish) prepared by blending the various materials, adding a solvent, and stirring to dissolve the mixture. The components shown in Table 1 were blended in the mass proportions shown in Table 1, and then toluene was added to a solids content of 20%, followed by stirring to dissolve the mixture, to prepare the resin compositions (varnishes) of Examples 1 to 9 and Comparative Examples 1 and 2. The varnishes were then transferred to airtight containers and stored in a thermostatic chamber at 30°C for three days, and the degree of gelation before and after storage for three days was evaluated. Evaluation was performed by placing a spoon into the varnish and scooping up the varnish, based on the behavior of the spoon according to the following evaluation criteria. <Crocodile Spot Life Evaluation Criteria> 〇: Liquidity △: Although it has fluidity, it is sticky and the resin composition adheres to the medicine spoon. ×: solidified, no fluidity

[0074] (2) Resin flow amount during primary processing In this invention, resin flow during primary processing refers to resin flow during heat pressing (primary processing) when bonding a coverlay film or adhesive sheet with a semi-cured (B-stage) adhesive layer to an arbitrary adherend. The first release substrate was peeled from a 25 μm-thick adhesive sheet described below, and the sheet was roll-laminated with a 50 μm-thick polyimide film (Kapton, manufactured by Toray DuPont Co., Ltd.) at 120°C, 0.3 MPa, and 1.0 m / min. This laminate was punched from the polyimide film side using a visual punch (manufactured by Nogami Giken Co., Ltd.) to create three 1.0 mm diameter openings. The second release substrate was peeled from this laminate with openings, and the laminate was laid on the shiny side of a 35 μm-thick electrolytic copper foil (GTS-MP, manufactured by Furukawa Electric Co., Ltd.). The laminate was then heat-pressed at 180°C, 2.7 MPa, and 60 minutes for adhesion and complete curing, resulting in a sample for evaluating the amount of resin flow during primary processing. The amount of resin flow during the primary processing was measured at four locations on the top, bottom, left and right of each opening, by measuring the maximum length of resin that flowed inside the opening, and calculating the average value. <Evaluation criteria for resin flow during primary processing> ○: Less than 0.15 mm △: 0.15mm or more, less than 0.20mm ×: 0.20mm or more

[0075] (3) Resin flow amount during secondary processing In this invention, resin flow during secondary processing refers to resin flow during secondary heat-press processing, such as reinforcing plate processing or shielding film processing, of an adhesive layer that has been fully cured after a primary heat-press process. The first release substrate was peeled from a 25 μm-thick adhesive sheet (described below), and roll-laminated with a 125 μm-thick polyimide film (Kapton, manufactured by DuPont-Toray Co., Ltd.) at 120°C, 0.3 MPa, and 1.0 m / min. The second release substrate was peeled from this laminate, and the laminate was laid up on a 125 μm-thick polyimide film (Kapton, manufactured by DuPont-Toray Co., Ltd.). This was then heat-pressed at 180°C, 2.7 MPa, and 60 minutes to obtain a fully cured laminate. The fully cured laminate was punched out using a visual punch (manufactured by Nogami Giken Co., Ltd.) to obtain eight 1.0 mm diameter disk-shaped samples. Using this disk-shaped sample, a heat press was performed to simulate secondary processing using a configuration consisting of a 1.5 mm thick SUS plate, a 60 μm thick OPP film (Toray Industries, Inc., Torayfan), a 38 μm thick silicone-based release PET film (Mitsui Chemicals Tocello, Inc., SP-PET-O3-BU), one 1.0 mm diameter disk-shaped sample, a 38 μm thick silicone-based release PET film (Mitsui Chemicals Tocello, Inc., SP-PET-O3-BU), a 60 μm thick OPP film (Toray Industries, Inc., Torayfan), and a 1.5 mm thick SUS plate. The heat press conditions were 160 °C, 2 MPa, and 30 minutes. The resin flow amount during secondary processing was measured by measuring the maximum length of resin flowing from the outer periphery of eight heat-pressed disk-shaped samples intended for secondary processing, and calculating the average value. <Evaluation criteria for resin flow during secondary processing> ○: Less than 0.10 mm △: 0.10mm or more, less than 0.15mm ×: 0.15mm or more

[0076] (4) Peel strength (adhesion) The first release substrate was peeled from a 25 μm-thick adhesive sheet (described below) and roll-laminated with a 50 μm-thick polyimide film (Kapton, manufactured by Toray DuPont Co., Ltd.) at 120°C, 0.3 MPa, and 1.0 m / min. The second release substrate was peeled from this laminate and laid up on the shiny side of a 35 μm-thick electrolytic copper foil (GTS-MP, manufactured by Furukawa Electric Co., Ltd.). The laminate was then hot-pressed at 180°C, 2.7 MPa, and 60 minutes for adhesion and complete curing to obtain a sample for peel strength evaluation. Peel strength was measured by a 90° peel test at 23°C, with the film pulled at a tensile speed of 50 mm / min. This test indicates adhesive strength at room temperature. <Evaluation criteria for peel strength> ◎: 0.7N / mm or more ○: 0.5N / mm or more, less than 0.7N / mm △: 0.3N / mm or more, less than 0.5N / mm ×: Less than 0.3N / mm

[0077] (5) Solder heat resistance The first release substrate was peeled from a 25 μm-thick adhesive sheet (described below) and roll-laminated to a 50 μm-thick polyimide film (Kapton, manufactured by Toray DuPont Co., Ltd.) or the polyimide side of a single-sided flexible copper-clad laminate (ESPANEX, manufactured by Nippon Steel Chemical & Material Co., Ltd., copper foil thickness 18 μm, polyimide thickness 25 μm) at 120°C, 0.3 MPa, and 1.0 m / min. The second release substrate was peeled from this laminate and laid up on the shiny side of a 35 μm-thick electrolytic copper foil (GTS-MP, manufactured by Furukawa Electric Co., Ltd.) or a double-sided flexible copper-clad laminate (ESPANEX, manufactured by Nippon Steel Chemical & Material Co., Ltd., copper foil thickness 18 μm, polyimide thickness 25 μm). The laminate was then hot-pressed at 180°C, 2.7 MPa, and 60 minutes for adhesion and complete curing to obtain a sample for evaluation of solder heat resistance. A 25mm x 25mm sample piece was prepared from this evaluation sample, dried at 105°C for 1 hour, and then floated in a molten solder bath at each temperature for 30 seconds to measure the temperature at which no appearance defects such as blistering occurred. <Evaluation criteria for solder heat resistance> 〇: 290℃ or higher △: 260℃ or higher, less than 290℃ ×: Less than 260℃

[0078] (6) Dielectric constant (Dk) and dielectric loss tangent (Df) Two 25 μm-thick adhesive sheets (described below) were used. The first release substrate was peeled off from each sheet, and the adhesive layers were roll-laminated together at 120°C, 0.3 MPa, and 1.0 m / min. This laminate was then heat-pressed at 180°C and 2.7 MPa for 60 minutes to bond and fully cure the adhesive, yielding a sample for evaluation of dielectric constant and dielectric loss tangent. The second release substrate was peeled off and the cured adhesive sheet was evaluated. The dielectric constant and dielectric loss tangent were measured at a frequency of 10 GHz using a vector network analyzer (Rohde & Schwarz GmbH & Co. KG, ZVB20) and a cavity resonator fixture (Keycom Corporation, TMR-10A) using a perturbation cavity resonator method. <Evaluation criteria for dielectric constant> ○: 2.5 or less △: Over 2.5, 3.0 or less ×: Over 3.0 <Evaluation criteria for dielectric loss tangent> 〇: 0.005 or less △: Over 0.005, 0.010 or less ×: More than 0.010

[0079] (7) Dynamic viscoelasticity measurement at 180°C Using a 25 μm-thick adhesive sheet (described below), the adhesive layers were roll-laminated at 120°C, 0.3 MPa, and 1.0 m / min to achieve a 1.2 mm adhesive layer thickness. This laminate was then heat-pressed at 180°C and 2.7 MPa for 60 minutes to bond and fully cure the adhesive, yielding a sample for evaluation of dynamic viscoelasticity at 180°C. Dynamic viscoelasticity at 180°C was measured by peeling off the second release substrate and evaluating the cured adhesive sheet alone. Using a rheometer (TA Instruments Japan, Inc., ARES-G2), the sample was preheated to 180°C for 2 minutes and then measured for time dependence in torsion mode at 180°C, a frequency of 1 Hz, and a strain of 20% for 20 minutes. The loss tangent (tanδ) value 5 minutes after the start of measurement was designated as T1, the loss tangent value 10 minutes after the start of measurement as T2, and the loss tangent value 15 minutes after the start of measurement as T3. The average values ​​of the three samples were calculated. <Evaluation criteria for dynamic viscoelasticity measurement at 180°C> ○: Loss tangent is 0.1 or less △: Loss tangent is over 0.1, 0.2 or less ×: Loss tangent exceeds 0.2

[0080] [Adjustment of resin composition, preparation of adhesive sheet] The components shown in Table 1 were mixed in the mass ratios shown in Table 1, and then toluene was added to give a solid content of 20%, followed by stirring and dissolution to prepare resin compositions for Examples 1 to 9 and Comparative Examples 1 and 2. Each resin composition was applied to a 38 μm thick silicone-based release PET film (Mitsui Chemicals Tocello Co., Ltd., SP-PET-O3-BU) and dried at 120°C for 5 minutes to create a 25 μm thick adhesive layer (B-stage state). A 50 μm thick silicone-based release PET film (Mitsui Chemicals Tohcello Co., Ltd., SP-PET-O3-BU) was roll-laminated onto the dry side of the adhesive layer under conditions of 100°C, 0.3 MPa, and 1.0 m / min to create an adhesive sheet. Here, the first release substrate is a laminate substrate (a silicone-based release PET film having a thickness of 50 μm), and the second release substrate is a coated substrate (a silicone-based release PET film having a thickness of 38 μm).

[0081] [Table 1]

[0082] The components shown in Table 1 are as follows:

[0083] (1) Modified polypropylene resin A: Acid-modified polypropylene resin

[0084] (2) Epoxy resin B Epoxy resin B1: Epoxidized polybutadiene Epoxy resin B2: Naphthalene skeleton modified multifunctional epoxy resin Epoxy resin B3: Dicyclopentadiene type epoxy resin Epoxy resin B4: Fluorine-containing epoxy resin

[0085] (3) Thermoplastic resin C: Acid-modified SEBS resin

[0086] (4) Carbodiimide resin D

[0087] As can be seen from a comparison of Examples 1 to 9 and Comparative Examples 1 and 2 in Table 1, when the content of modified polypropylene resin is less than 50 parts by mass, sufficient physical properties are exhibited in terms of the amount of resin flow during primary processing, peel strength, solder heat resistance, dielectric constant, and dielectric loss tangent, but the loss tangent in dynamic viscoelasticity measurement at 180°C exceeds 0.2, so the resin flow properties during secondary processing are unsatisfactory. Therefore, from the perspective of resin flow properties during secondary processing, it is clear that the content of modified polypropylene resin is preferably 50 parts by mass or more.

[0088] Furthermore, as can be seen from Examples 1 and 5 to 7 in Table 1, when the epoxy resin content exceeds 20 parts by mass, the resin flow amount during primary processing, the resin flow amount during secondary processing, peel strength, solder heat resistance, and dielectric constant are sufficient, but the dielectric loss tangent deteriorates. Therefore, from the viewpoint of the dielectric loss tangent, it is clear that the epoxy resin content is preferably 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the solid content.

[0089] Furthermore, although any epoxy resin can be used as the type of epoxy resin, the loss tangent is smallest when epoxy resin B1 is used, and therefore it is clear that it is more preferable to use a non-alicyclic epoxy resin such as an epoxidized polyolefin as the epoxy resin.

[0090] Regarding the amount of carbodiimide resin added, it has been confirmed that a sufficient pot life can be ensured for the varnish by adding 0.4 parts by mass of carbodiimide resin, and therefore, from the viewpoint of pot life, it is preferable that the content of carbodiimide resin be 0.4 parts by mass or less.

[0091] Regarding the addition of a curing accelerator, it has been confirmed that sufficient physical properties are exhibited without the addition of a curing accelerator, so the addition of a curing accelerator is unnecessary, and from the viewpoint of cost reduction, it is preferable not to add a curing accelerator. [Industrial Applicability]

[0092] The resin composition of the present invention has excellent adhesion, heat resistance, and insulation reliability, as well as good resin flow properties during hot pressing (secondary processing) such as reinforcing plate processing and shielding film processing. Coverlay films, adhesive sheets, resin-coated metal foils, and metal-clad laminates made using the resin composition of the present invention are useful for producing flexible printed wiring boards for high-frequency signal transmission, which require low dielectric properties (low dielectric constant, low dielectric dissipation factor).

Claims

1. A resin composition used in an adhesive layer of a laminated substrate, Contains an acid-modified polypropylene resin (A) and an epoxy resin (B), the acid-modified polypropylene resin (A) is a resin modified with at least one carboxylic acid compound or a derivative of a carboxylic acid compound, the epoxy resin (B) is a naphthalene skeleton-modified polyfunctional epoxy resin or a fluorine-containing epoxy resin, the content of the epoxy resin (B) is 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the solid content of the resin composition, and the content of the acid-modified polypropylene-based resin (A) is 50 parts by mass or more per 100 parts by mass of the total content of the acid-modified polypropylene-based resin (A) and the epoxy resin (B), The acid-modified polypropylene resin (A) has an acid value of 5 mgKOH / g or more and a weight average molecular weight of 20,000 or more and 180,000 or less, one or more curing accelerators selected from a tertiary amine curing accelerator, a tertiary amine salt curing accelerator, and an imidazole curing accelerator are not added, a laminate is prepared by laminating a 25 μm thick sheet of the semi-cured resin on a 50 μm thick film, and the laminate is then laminated on a 35 μm thick electrolytic copper foil with the film facing outward, and the laminate is then hot-pressed for 60 minutes under conditions of 180° C. and 2.7 MPa, and the average maximum length of resin flowing out to the outside of the laminate (i.e., the amount of resin flow during primary processing) is 0.09 mm or less; In a dynamic viscoelasticity measurement at 180°C in a state in which the composition is completely cured by hot pressing for 60 minutes under conditions of 180°C and 2.7 MPa, when the value of the loss tangent (tanδ) 5 minutes after the start of the measurement is T1, the value of the loss tangent 10 minutes after the start of the measurement is T2, and the value of the loss tangent 15 minutes after the start of the measurement is T3, all of T1, T2, and T3 are 0.2 or less, A resin composition characterized in that when a 25 μm thick sheet is formed in a fully cured state by heat pressing for 60 minutes at 180°C and 2.7 MPa, and then sandwiched between 125 μm thick films of the same shape on both sides to form a laminate, this laminate is punched out to create a disc-shaped test specimen, and the test specimen is heat pressed in the thickness direction at 160°C, 2 MPa, and 30 minutes, the average maximum length of resin flowing out from the periphery of the test specimen (i.e., the amount of resin flow during secondary processing) is less than 0.15 mm.

2. An adhesive layer formed using the resin composition according to claim 1; a substrate in contact with at least one surface of the adhesive layer, The laminate includes a substrate that is any one of a resin substrate, a release resin substrate, a paper substrate, a release paper substrate, and a metal substrate. Coverlay film, adhesive sheet, resin-backed metal foil, or metal-clad laminate.

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