Resin films, laminates, metal-clad laminates

Abstract

To provide a resin film which can satisfy adhesion to a polyimide resin film as a base material and adhesion to a metal layer (for example, copper foil having low roughness) that can achieve high speed transmission and has small roughness, while satisfying low dielectric characteristics required for 5 G and 6 G.SOLUTION: An SPS resin film contains syndiotactic polystyrene (SPS), and further contains polyphenylene ether (PPE) and a rubbery elastic body, wherein as for a mass ratio of each component in 100 pts.mass of the SPS resin film, the syndiotactic polystyrene is more than 50 pts.mass and 92 pts.mass or less, the polyphenylene ether is 5 pts.mass or more and less than 30 pts.mass, and the rubbery elastic body is 3 pts.mass or more and 20 pts.mass or less, and the polyphenylene ether (PPE) has a hydroxyl group (-OH group) at its terminal.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an SPS resin film, a laminate having the SPS resin film, and a metal-clad laminate. [Background Art]

[0002] In 5G and 6G societies, further higher-speed transmission is required for printed wiring boards. The insulating layer constituting a printed wiring board is required to have low dielectric properties and adhesion to metal layers such as copper foil with low roughness. Syndiotactic polystyrene (SPS) is attracting attention as a material for printed wiring boards because it is excellent in electrical properties (low dielectric properties), chemical resistance and low water absorption. It has been disclosed that a film containing syndiotactic polystyrene and a thermoplastic resin having compatibility with the syndiotactic polystyrene is used as a coverlay film that adheres well to a printed wiring board (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-53422 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] However, from the viewpoint of providing a resin film that satisfies the low dielectric properties required for 5G and 6G, and also satisfies adhesiveness (also referred to as adhesion) to a polyimide resin film as a base material and adhesiveness to a low-roughness metal layer (for example, low-roughness copper foil) capable of realizing high-speed transmission, the resin film described in the above-mentioned Patent Document 1 cannot be said to be sufficient.

[0005] Therefore, the present invention has been made in view of the above circumstances, and aims to provide a resin film that satisfies the low dielectric properties required for 5G and 6G, and further satisfies adhesion to a polyimide resin film that serves as a base material, and adhesion to a metal layer with low roughness (for example, low-roughness copper foil) that enables high-speed transmission. Furthermore, the present invention aims to provide laminates and metal-clad laminates having the above-mentioned resin film. [Means for solving the problem]

[0006] As a result of extensive research to solve the above problems, the present inventors have found that an SPS resin film containing a styrene polymer (SPS) having a syndiotactic structure, a specific polyphenylene ether (PPE), and a rubbery elastic material, wherein the content ratio of each component contained in the SPS resin film is defined within a specific range, can solve the above problems, and have completed the present invention.

[0007] The present invention encompasses the following embodiments. [1] An SPS resin film containing syndiotactic polystyrene (SPS), and further containing polyphenylene ether (PPE) and a rubbery elastic material, The mass ratio of each component in 100 parts by mass of the SPS resin film is: The amount of syndiotactic polystyrene is more than 50 parts by mass and 92 parts by mass or less. The polyphenylene ether is present in amounts of 5 parts by mass or more and less than 30 parts by mass. The rubber-like elastic material is present in amounts of 3 to 20 parts by mass, The aforementioned polyphenylene ether (PPE) is an SPS resin film having hydroxyl groups (-OH groups) at its ends. [2] The SPS resin film according to [1], wherein the weight-average molecular weight (Mw) of the polyphenylene ether (PPE) is 10,000 to 100,000 g / mol. [3] The SPS resin film according to [1], wherein the rubbery elastic body comprises a hydrogenated styrene-butadiene-styrene block copolymer (SBS). [4] The SPS resin film according to [3], wherein the mass percentage of styrene in the hydrogenated styrene-butadiene-styrene block copolymer (SBS) is 25% by mass or more and 70% by mass or less. [5] The SPS resin film according to [3] or [4], wherein the melt flow rate (MFR) of the hydrogenated styrene-butadiene-styrene block copolymer (SBS), measured at 230°C and 2.16 kgf, is 0 g / 10 min or more and 10 g / 10 min or less. [6] The SPS resin film according to any one of [1] to [5], wherein the relative permittivity of the SPS resin film at a frequency of 28 GHz is 2.8 or less and the dielectric loss tangent is 0.002 or less. [7] The SPS resin film according to any one of [1] to [6], wherein the tensile modulus of elasticity of the SPS resin film, as measured by a method in accordance with JIS K7127, is 2.4 GPa or more and 3.1 GPa or less. [8] The SPS resin film described in [1], obtained by following a) to d) below using the SPS resin film described in [1], wherein the tensile modulus of elasticity measured by a method in accordance with the measurement method of JIS K7127 is 2.7 GPa or more and 3.6 GPa or less. a) Copper foil is placed on both sides of the SPS resin film. b) Using a hot press machine, sandwich the material between 1 mm thick stainless steel plates, set the hot plate temperature to 80°C, and begin heat pressing with a surface pressure of 3 MPa. Increase the temperature at a heating rate of 7°C / min until the hot plate temperature reaches 290°C while heat pressing is being performed. c) Once it reaches 290°C, cool it down to 230°C at a rate of 4°C / min, then release the pressure and remove it. d) Etch and remove the copper foil, and extract only the SPS resin film. [9] An SPS resin film as described in any of [1] to [8], A laminate formed by laminating a heat-resistant resin film that does not have a melting point below 300°C.

[10] The laminate according to [9], wherein the linear thermal expansion coefficient (CTE) of the heat-resistant resin film is 50 ppm / °C or less.

[11] The laminate according to [9], wherein the surface of the SPS resin film on the side in contact with the heat-resistant resin film is surface-treated by any treatment method selected from corona treatment, plasma treatment, and ultraviolet treatment. A metal-clad laminate in which a metal layer is laminated on the SPS resin film on the side opposite to the side on which the heat-resistant resin film is arranged, relative to the laminate described in any of

[12] [9] to

[11] .

[13] The metal-clad laminate according to

[12] , wherein the metal layer is copper foil, and the surface roughness (Rz) of the copper foil surface that contacts the SPS resin film is 1 μm or less. A method for manufacturing a laminate described in

[14] [9], comprising the step of arranging the SPS resin film, the heat-resistant resin film, and the SPS resin film in this order and heat-pressing them together to obtain a laminate.

[15] The method for manufacturing a laminate according to

[14] , wherein the heat-sealing is performed such that, when the melting point of the SPS resin film is Tm (°C), the maximum temperature during heat-sealing is in a temperature range of Tm-30°C or more and Tm+30°C or less. A method for manufacturing a metal-clad laminate described in

[16]

[12] , The metal layer, the SPS resin film, the heat-resistant resin film, and the SPS resin film are arranged in this order and heat-pressed together, A method for manufacturing a metal-clad laminate, comprising the steps of arranging the metal layer, the SPS resin film, the heat-resistant resin film, the SPS resin film, and the metal layer in this order and heat-pressing them together to obtain a metal-clad laminate.

[17] The method for manufacturing a metal-clad laminate according to

[16] , wherein the thermocompression bonding is performed such that, when the melting point of the SPS resin film is Tm (°C), the maximum temperature during thermocompression bonding is in a temperature range of Tm-30°C or more and Tm+30°C or less. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin film that satisfies the low dielectric properties required for 5G and 6G, and also satisfies adhesiveness to a polyimide resin film serving as a base material and adhesiveness to a metal layer with low roughness that enables high-speed transmission (e.g., low-roughness copper foil). Further, according to the present invention, it is possible to provide a laminate and a metal-clad laminate having the above resin film. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] [Figure 1] It is a cross-sectional view showing an example of the configuration of the laminate of the present invention. [Figure 2] It is a cross-sectional view showing an example of the configuration of the metal-clad laminate of the present invention. [Figure 3] It is a schematic diagram for explaining the evaluation criteria of peeling mode performed in Examples. [Figure 4] It is a schematic diagram for explaining the evaluation criteria of peeling mode performed in Examples. [Figure 5] It is a schematic diagram for explaining the evaluation criteria of peeling mode performed in Examples.

[0010] Hereinafter, the SPS resin film of the present invention, a laminate including the SPS resin film for printed wiring boards and the like, and a metal-clad laminate formed using the laminate will be described. However, the description of the constituent requirements described below is an example as one embodiment of the present invention, and the present invention is not limited to these contents. The following definitions of terms apply throughout the present specification and claims. The melting point in the present invention can be measured in accordance with JIS K 7121. Specifically, approximately 5 mg of a measurement sample is weighed from a melt-extruded resin film, and measurement is performed by heating from 20°C to 380°C at a heating rate of 10°C / min using a differential scanning calorimeter (high-sensitivity differential scanning calorimeter X-DSC 7000, manufactured by SII Technologies). The film thickness of a resin film, metal layer (metal foil film), etc. is an average value obtained by observing the cross-section of the measurement object using a microscope, measuring the thickness at 5 points, and averaging the measured values.

[0011] (SPS Resin Film) The SPS resin film of the present invention contains syndiotactic polystyrene (SPS), and further contains polyphenylene ether (PPE) and a rubber-like elastic body. The aforementioned polyphenylene ether (PPE) has a hydroxyl group (-OH group) at a terminal end. The mass ratio of each component based on 100 parts by mass of the SPS resin film of the present invention is as follows: the content of syndiotactic polystyrene is more than 50 parts by mass and 92 parts by mass or less, the content of polyphenylene ether is 5 parts by mass or more and less than 30 parts by mass, the content of the rubber-like elastic body is 3 parts by mass or more and 20 parts by mass or less.

[0012] The SPS resin film is formed using a resin composition containing syndiotactic polystyrene (SPS), which is a styrenic polymer having a syndiotactic structure.

[0013] In a resin composition containing SPS for forming an SPS resin film (also referred to as a resin composition for forming an SPS resin film), it is necessary that (i) syndiotactic polystyrene (SPS) is contained as a resin component; furthermore, in the present invention, it is necessary that (ii) polyphenylene ether (PPE) having a hydroxyl group (-OH group) at a terminal end and (iii) a rubber-like elastic body are contained. Furthermore, in order to impart various functions such as adjustment of strength, insulation, heat resistance, and coefficient of linear thermal expansion (CTE) of the resin film, the resin composition containing SPS may contain other components such as a filler and various additives within a range that does not impair the object of the present invention.

[0014] Hereinafter, each component contained in the resin composition containing SPS will be described.

[0015] Syndiotactic polystyrene (SPS) In styrene polymers having a syndiotactic structure, the syndiotactic structure is one in which the stereochemical structure is syndiotactic, that is, the phenyl groups, which are the side chains, are alternately positioned in opposite directions relative to the main chain formed from carbon-carbon bonds. Its tacticity is quantified by nuclear magnetic resonance (13C-NMR) using isotopic carbon. Tacticity measured by 13C-NMR can be expressed by the proportion of consecutive constituent units, for example, a dyad for two units, a triad for three units, and a pentad for five units. However, the styrene polymer having a syndiotactic structure as referred to in this invention refers to polystyrene, poly(alkylstyrene), poly(arylstyrene), poly(halogenated styrene), poly(halogenated alkylstyrene), poly(alkoxystyrene), poly(vinyl benzoate ester), hydrogenated polymers thereof, mixtures thereof, or copolymers mainly composed of these, which usually have a syndiotacticity of 75% or more, preferably 85% or more, in racemic dyads, or 30% or more, preferably 50% or more, in racemic pentads. Here, poly(alkylstyrene) includes poly(methylstyrene), poly(ethylstyrene), poly(isopropylstyrene), poly(tert-butylstyrene), etc., poly(arylstyrene) includes poly(phenylstyrene), poly(vinylnaphthalene), poly(vinylstyrene), etc., and poly(halogenated styrene) includes poly(chlorostyrene), poly(bromostyrene), poly(fluorostyrene), etc. Furthermore, poly(halogenated alkylstyrene) includes poly(chloromethylstyrene), etc., and poly(alkoxystyrene) includes poly(methoxystyrene), poly(ethoxystyrene), etc.

[0016] Preferred styrene-based polymers among these include polystyrene, poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tert-butylstyrene), poly(p-chlorostyrene), poly(m-chlorostyrene), poly(p-fluorostyrene), hydrogenated polystyrene, and copolymers containing these structural units.

[0017] Such styrene polymers having a syndiotactic structure can be produced, for example, by polymerizing a styrene monomer (a monomer corresponding to the above-mentioned styrene polymer) using a titanium compound and a condensation product of water and trialkylaluminum as catalysts in an inert hydrocarbon solvent or in the absence of a solvent (Japanese Patent Publication No. 62-187708). Furthermore, poly(alkyl styrene halogenates) can be obtained by methods described in Japanese Patent Publication No. 1-46912, and their hydrogenated polymers can be obtained by methods described in Japanese Patent Publication No. 1-178505, etc.

[0018] Furthermore, among these styrene-based polymers having a syndiotactic structure, in the present invention, those with a tacticity of 70% or more in the racemic pentad and a weight-average molecular weight of 500,000 to 800,000 are particularly preferred from the viewpoint of heat resistance and mechanical strength.

[0019] The syndiotactic polystyrene content in the SPS resin film of the present invention is preferably more than 50 parts by mass and 92 parts by mass or less, and more preferably 55 parts by mass or more and 75 parts by mass or less, and more preferably 60 parts by mass or more and 75 parts by mass or less, per 100 parts by mass of the SPS resin film. Too little will worsen the dielectric properties, and too much will weaken the adhesion strength.

[0020] <Polyphenylene ether (PPE)> The polyphenylene ether according to the present invention has a hydroxyl group (-OH group) at its terminus. Furthermore, the weight-average molecular weight (Mw) of polyphenylene ether is preferably 10,000 to 100,000 g / mol, and more preferably 30,000 to 70,000 g / mol, from the viewpoint of improving adhesion strength with different resin films such as polyimide. The amount of phenol-terminated groups in polyphenylene ether is preferably 300 ppm to 8000 ppm, and more preferably 500 ppm to 2000 ppm, because it makes it difficult to separate the phenol-terminated groups from the SPS resin, reducing film appearance defects caused by polyphenylene ether aggregates and improving yield. The amount of phenol-terminated groups in polyphenylene ether can be measured by methods such as titration and infrared spectroscopy (IR).

[0021] The polyphenylene ether content in the SPS resin film of the present invention is preferably 5 parts by mass or more and less than 30 parts by mass of polyphenylene ether per 100 parts by mass of SPS resin film. This is preferable because it can improve the film strength of the SPS resin film while maintaining adhesion to heat-resistant films such as polyimide, and can also maintain low dielectric properties. In this case, it is preferable that the content is 12 parts by mass or more and 28 parts by mass or less, and more preferably 15 parts by mass or more and 25 parts by mass or less.

[0022] <Rubber-like elastic material> Specific examples of rubbery elastic materials include, for example, natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene, polysulfide rubber, thiocol rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, styrene-butadiene block copolymer (SBR), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-isoprene-styrene block copolymer (SEPS), or ethylene propylene rubber (EPM), ethylene propylene Examples include olefin-based rubbers such as EPDM and linear low-density polyethylene elastomers, or core-shell type particulate elastic materials such as butadiene-acrylonitrile-styrene-core-shell rubber (ABS), methyl methacrylate-butadiene-styrene-core-shell rubber (MBS), methyl methacrylate-butyl acrylate-styrene-core-shell rubber (MAS), octyl acrylate-butadiene-styrene-core-shell rubber (MABS), alkyl acrylate-butadiene-acrylonitrile-styrene-core-shell rubber (AABS), butadiene-styrene-core-shell rubber (SBR), and siloxane-containing core-shell rubbers including methyl methacrylate-butyl acrylate-siloxane, or rubbers modified from these.

[0023] The content of the rubbery elastic body in the SPS resin film of the present invention is preferably 3 parts by mass or more and 20 parts by mass or less, preferably 5 parts by mass or more and 18 parts by mass or less, and more preferably 7 parts by mass or more and 13 parts by mass or less, per 100 parts by mass of the SPS resin film.

[0024] The rubber-like elastic material according to the present invention preferably contains a hydrogenated styrene-butadiene-styrene block copolymer (SBS). The rubbery elastic material according to the present invention may include other rubbery elastic materials other than hydrogenated styrene-butadiene-styrene block copolymer (SBS). When hydrogen is added to styrene-butadiene-styrene block copolymer (SBS), hydrogen is added to the C=C double bond in the butadiene portion, yielding hydrogenated styrene-ethylene-butylene-styrene block copolymer (SEBS). In the present invention, it is more preferable that hydrogenated styrene-ethylene-butylene-styrene block copolymer (SEBS), which is a hydrogenated styrene-butadiene-styrene block copolymer (SBS), is contained in the rubbery elastic body. The above-mentioned "hydrogenated styrene-butadiene-styrene block copolymer (SBS)" refers to any hydrogenated styrene-butadiene-styrene block copolymer (SBS) to which hydrogen has been added. This includes hydrogenated SBS to which hydrogen has been partially added, or hydrogenated SBS to which hydrogen has been added to all butadiene portions.

[0025] The mass percentage of styrene in the hydrogenated styrene-butadiene-styrene block copolymer is preferably 25% by mass or more and 70% by mass or less, and more preferably 25% by mass or more and 50% by mass or less, from the viewpoint of improving the adhesion (fit) of the SPS resin film to the metal layer (e.g., low-roughness copper foil). The melt flow rate (MFR) of the hydrogenated styrene-butadiene-styrene block copolymer, measured at 230°C and 2.16 kgf, is preferably 0 g / 10 min to 10 g / 10 min, more preferably 0 g / 10 min to 3 g / 10 min, and even more preferably 0 g / 10 min to 1 g / 10 min, from the viewpoint of further increasing the film strength of the SPS resin film.

[0026] In resin compositions containing SPS, as described above, in order to impart various functions to the resin film, such as strength, insulation, heat resistance, and adjustment of the coefficient of linear thermal expansion (CTE), other components such as fillers and various additives may be included in addition to SPS, PPE, and rubbery elastic materials. For example, additives include antioxidants, light stabilizers, ultraviolet absorbers, crystal nucleating agents, plasticizers, and filler dispersants.

[0027] <Other ingredients> <<Filler>> Examples of fillers include inorganic fillers and organic fillers, which can be used individually or in combination.

[0028] Examples of inorganic fillers include mica, talc, boron nitride, magnesium oxide, silica, diatomaceous earth, titanium dioxide, and zinc oxide. Among these, inorganic fillers such as mica, talc, boron nitride, magnesium oxide, and silica are preferred. The organic fillers are not particularly limited, but examples include organic particles such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyamide, polycarbonate, polyimide, polyether ketone, polyether ether ketone, polymethyl methacrylate, liquid crystal polymer, and polytetrafluoroethylene. Inorganic fillers and organic fillers may be selected from the above and used individually, or two or more may be used in combination. When combining two or more, a combination of inorganic fillers and organic fillers is also acceptable.

[0029] In addition to the additives mentioned above, other substances such as antiblocking agents, antistatic agents, process oils, mold release agents, compatibilizers, flame retardants, flame retardant aids, pigments, and inorganic fillers can also be incorporated. In the present invention, there is no need to make a clear distinction between fillers and various additives. For example, some substances may be classified as both fillers and inorganic fillers, or as both antiblocking agents and inorganic fillers. However, in the present invention, any substance that can be used as one of the fillers or various additives mentioned above can be included in a resin composition containing SPS.

[0030] <<Various Additives>> Various additives, as exemplified below, can be incorporated as long as they do not hinder the objective of the present invention.

[0031] [Antiblocking agents (AB agents)] Examples of antiblocking agents include the following inorganic or organic particles. Examples of inorganic particles include oxides, hydroxides, sulfides, nitrogenides, halides, carbonates, sulfates, acetates, phosphates, phosphites, organic carboxylates, silicates, titanates, borates, and their hydrated compounds, composite compounds centered on these, and natural mineral particles.

[0032] Specifically, these include Group IA element compounds such as lithium fluoride and borax (hydrated sodium borate), magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, magnesium acetate, magnesium fluoride, magnesium titanate, magnesium silicate, hydrated magnesium silicate (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, calcium titanate, strontium titanate, barium carbonate, barium phosphate, barium sulfate, barium sulfite, and other Group IIA element compounds, as well as titanium dioxide (titania), titanium monoxide, titanium nitride, and zirconium dioxide (zirconium). Examples include particles of Group IVA elements such as zirconium monoxide, Group VIA elements such as molybdenum dioxide, molybdenum trioxide, and molybdenum sulfide, Group VIA elements such as manganese chloride and manganese acetate, Group VIII elements such as cobalt chloride and cobalt acetate, Group IB elements such as cuprous iodide, Group IIB elements such as zinc oxide and zinc acetate, Group IIIB elements such as aluminum oxide (alumina), aluminum hydroxide, aluminum fluoride, and aluminasilicate (alumina silicate, kaolin, kaolinite), Group IVB elements such as silicon oxide (silica, silica gel), graphite, carbon, graphite, and glass, and particles of natural minerals such as carnalite, kyninite, mica, and biroseite.

[0033] Examples of organic particles include Teflon, melamine resins, styrene-divinylbenzene copolymers, acrylic resins, and crosslinked products thereof.

[0034] [Antioxidant] Antioxidants can be arbitrarily selected from known types such as phosphorus-based, phenol-based, and sulfur-based antioxidants. These antioxidants can be used individually or in combination of two or more types.

[0035] [Nuclear agent] As nucleating agents, metal salts of carboxylic acids, including aluminum di(pt-butylbenzoate), metal salts of phosphoric acid, including sodium methylenebis(2,4-di-t-butylphenol) acid phosphate, talc, phthalocyanine derivatives, etc., can be arbitrarily selected and used. These nucleating agents can be used individually or in combination of two or more.

[0036] [Plasticizer] As plasticizers, polyethylene glycol, polyamide oligomers, ethylene bis-stearoamide, phthalate esters, polystyrene oligomers, polyethylene wax, silicone oil, and other known materials can be arbitrarily selected and used. These plasticizers can be used individually or in combination of two or more.

[0037] [Release agent] As a release agent, polyethylene wax, silicone oil, long-chain carboxylic acids, long-chain metal carboxylic acid salts, and other known substances can be arbitrarily selected and used. These release agents can be used individually or in combination of two or more.

[0038] [Process oil] In the present invention, process oil may be further incorporated. Process oils are broadly classified into paraffinic oils, naphthenic oils, and aromatic oils depending on the type of oil, but paraffinic oil is preferred among them. The viscosity of the process oil is preferably 15 to 600 cs at 40°C, and more preferably 15 to 500 cs. These process oils can be used individually or in combination of two or more.

[0039] [Compatibilizer] The compatibilizer referred to in this invention is formulated to improve the affinity between SPS, PPE, and rubbery elastic material, thereby effectively compatibilizing them, and also to improve the affinity between SPS and inorganic fillers. Specifically, examples include polymers that have compatibility or affinity with SPS and that have polar groups.

[0040] Here, polymers having compatibility or affinity with SPS refer to polymers that contain chains exhibiting compatibility or affinity with SPS within their polymer chains. Examples of polymers exhibiting such compatibility or affinity include those having syndiotactic polystyrene, atactic polystyrene, isotactic polystyrene, styrene copolymers, polyphenylene ether, polyvinyl methyl ether, etc., as the main chain, block, or graft chain.

[0041] Furthermore, the polar groups referred to here can be any groups that improve adhesion to inorganic fillers, and specifically include acid anhydride groups, carboxylic acid groups, carboxylic acid ester groups, carboxylic acid chloride groups, carboxylic acid amide groups, carboxylic acid bases, sulfonic acid groups, sulfonic acid ester groups, sulfonate chloride groups, sulfonic acid amide groups, sulfonic acid bases, epoxy groups, amino groups, imide groups, oxazoline groups, and the like.

[0042] This compatibilizer can be obtained by reacting a polymer having compatibility or affinity with the above-mentioned SPS with a modifying agent described later, either in the presence or absence of a solvent and other resins. As a denaturing agent, for example, compounds containing an ethylenic double bond and a polar group within the same molecule can be used. Specifically, examples include maleic anhydride, maleic acid, maleic acid esters, maleimides and their N-substituted derivatives, maleates and other maleic acid derivatives, fumaric acid, fumaric acid esters, fumarates and other fumarates, itaconic anhydride, itaconic acid esters, itaconic acid derivatives and other itaconic acid derivatives, acrylic acid, acrylic acid esters, acrylamide, acrylicate and other acrylic acid derivatives, methacrylic acid, methacrylic acid esters, methacrylamide, methacrylate, methacrylic acid derivatives and other glycidyl methacrylate, etc. Among these, maleic anhydride, fumaric acid, and glycidyl methacrylate are particularly preferred.

[0043] Known methods can be used for modification, including melt-kneading at a temperature of 150°C to 350°C using a roll mill, Banbury mixer, extruder, etc., and heating in a solvent such as benzene, toluene, or xylene. Furthermore, to facilitate these reactions, it is effective to include radical generators such as benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxybenzoate, azobisisobutyronitrile, azobisisovaleronitrile, and 2,3-diphenyl-2,3-dimethylbutane in the reaction system. Of these, 2,3-diphenyl-2,3-dimethylbutane is particularly preferred.

[0044] Furthermore, a preferred modification method is melt-kneading in the presence of a radical generator. Other resins may also be added during the modification process. Specific examples of compatibilizers include styrene-maleic anhydride copolymer (SMA), styrene-glycidyl methacrylate copolymer, terminally carboxylic acid-modified polystyrene, terminally epoxy-modified polystyrene, terminally oxazoline-modified polystyrene, terminally amine-modified polystyrene, sulfonated polystyrene, styrene-based ionomers, styrene-methyl methacrylate-graft polymers, (styrene-glycidyl methacrylate)-methyl methacrylate-graft copolymers, acid-modified acrylic-styrene-graft polymers, (styrene-glycidyl methacrylate)-styrene-graft polymers, polybutylene terephthalate-polystyrene-graft polymers, modified styrene-based polymers such as maleic anhydride-modified PS, fumaric acid-modified PS, glycidyl methacrylate-modified PS, and amine-modified PS, as well as modified polyphenylene ether polymers such as (styrene-maleic anhydride)-polyphenylene ether-graft polymers, maleic anhydride-modified polyphenylene ether, glycidyl methacrylate-modified polyphenylene ether, and amine-modified polyphenylene ether.

[0045] Of these, modified PS and modified polyphenylene ether are particularly preferred. Furthermore, two or more of the above polymers can be used in combination. The polar group content in the compatibilizer is preferably in the range of 0.01 to 20% by mass, and more preferably 0.05 to 10% by mass, based on 100% by mass of the compatibilizer. A content of less than 0.01% by mass is undesirable because it requires the addition of a large amount of compatibilizer to achieve an adhesive effect with the inorganic filler, which may reduce the mechanical properties, heat resistance, and moldability of the composition. A content exceeding 20% ​​by mass is also undesirable because it may reduce compatibility with SPS.

[0046] The blending amount of the compatibilizer is 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, more preferably 1 to 5 parts by mass, based on 100 parts by mass of the total of SPS, PPE and rubber-like elastic body. If the amount is less than 0.1 part by mass, the adhesion effect with the inorganic filler is small, resulting in insufficient adhesion between the resin and the inorganic filler. Even if the blending amount exceeds 10 parts by mass, improvement in adhesion cannot be expected, which is economically disadvantageous.

[0047] [Inorganic filler] As the inorganic filler, granular and powdery fillers are preferred, and examples include talc, carbon black, graphite, titanium dioxide, silica, mica, calcium carbonate, calcium sulfate, barium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, oxysulfate, tin oxide, alumina, kaolin, silicon carbide, metal powder, glass powder, glass flakes, glass beads, and the like.

[0048] In addition, surface-treated fillers may be used as these fillers. The coupling agent used for surface treatment is used to improve the adhesion between the filler and the resin, and any conventionally known coupling agent such as so-called silane-based coupling agents and titanium-based coupling agents can be selected and used. One of these inorganic fillers may be used alone, or two or more thereof may be used in combination.

[0049] Kneading of the above components may be performed by various methods, such as a method of blending and melt-kneading at any stage of the syndiotactic polystyrene production process, or a method of blending and melt-kneading each component constituting the composition.

[0050] <Properties of SPS Resin Film> The dielectric constant of the SPS resin film at a frequency of 28 GHz is preferably as low as possible, but due to the need for a resin with solder heat resistance, it is preferably 2.8 or less, more preferably 2.0 to 2.8, and even more preferably 2.0 to 2.6. Similarly, the dielectric loss tangent of the SPS resin film at a frequency of 28 GHz is preferably as low as possible, but due to the need for a resin with solder heat resistance, it is preferably 0.002 or less, more preferably less than 0.0020, even more preferably 0.0016 or less, and even more preferably 0.0012 or less. Furthermore, the dielectric loss tangent of the SPS resin film at a frequency of 28 GHz is preferably 0.0005 to 0.0020 or less, more preferably less than 0.0005 to 0.0020, even more preferably 0.0005 to 0.0016, and even more preferably 0.0005 to 0.0012.

[0051] [Relative permittivity and dielectric loss tangent] The relative permittivity and dielectric loss tangent of resin films can be measured using the open-type resonator method with a network analyzer MS46122B (Anritsu) and an open-type resonator Fabry-Perot DPS-03 (KEYCOM) under conditions of 23°C, 50% humidity, and 28GHz frequency.

[0052] The tensile modulus of elasticity of the SPS resin film, as measured by a method conforming to the measurement method of JIS K7127, is preferably 2.4 GPa or more and 3.1 GPa or less, and more preferably 2.5 GPa or more and 2.9 GPa or less, from the viewpoint of improving the adhesion between the SPS resin film and the base material, such as the polyimide resin film or copper foil. Furthermore, the tensile modulus of elasticity of the SPS resin film after heat-pressing, as measured using the JIS K7127 measurement method, is preferably 2.7 GPa to 3.6 GPa, and more preferably 2.8 GPa to 3.5 GPa, from the viewpoint of improving the adhesion between the SPS resin film and the base material polyimide resin film or copper foil. The SPS resin film used for measuring the tensile modulus after heat bonding can be obtained by using an SPS resin film and following the steps a) to d) below. a) Copper foil is placed on both sides of the SPS resin film. b) Using a hot press machine, sandwich the material between 1 mm thick stainless steel plates, set the hot plate temperature to 80°C, and begin heat pressing with a surface pressure of 3 MPa. Increase the temperature at a heating rate of 7°C / min until the hot plate temperature reaches 290°C while heat pressing is being performed. c) Once it reaches 290°C, cool it down to 230°C at a rate of 4°C / min, then release the pressure and remove it. d) Etch and remove the copper foil, and extract only the SPS resin film.

[0053] The film thickness of the SPS resin film is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 5 μm to 60 μm, more preferably 10 μm to 60 μm, and even more preferably 20 μm to 55 μm. This is because within this range, metal-clad laminates with good dielectric properties and dimensional stability can be manufactured.

[0054] The melting point of the SPS resin film is preferably 260°C or higher.

[0055] Because the dielectric properties of the SPS resin film deteriorate significantly when it absorbs moisture, the water absorption rate of the SPS resin film is preferably 0.2% or less, more preferably 0.15% or less, even more preferably 0.10% or less, and particularly preferably 0.06% or less. Furthermore, the water absorption rate of the SPS resin film is preferably 0 to 0.2%, more preferably 0.01 to 0.15%, even more preferably 0.01 to 0.10%, and particularly preferably 0.03 to 0.06%.

[0056] [Water absorption rate] The water absorption rate can be determined by measuring it in accordance with the JIS K7209A method, under the conditions of immersion in water at 23°C for 24 hours. The water absorption rate is determined from the change in mass before and after flooding. Water absorption = ((mass after 24-hour water absorption test - mass before test) / mass before test) × 100

[0057] It is preferable that the surface of the SPS resin film is subjected to any one surface treatment selected from corona treatment, plasma treatment and ultraviolet treatment for reasons such as improving adhesion. In particular, in the laminate described later, it is preferable that the surface of the SPS resin film on the side in contact with the heat-resistant resin film is surface-treated by any treatment method selected from corona treatment, plasma treatment and ultraviolet treatment.

[0058] <Method for Producing SPS Resin Film> The SPS resin film can be obtained, for example, by molding the resin into a film shape via a melt extrusion molding method. The melt extrusion molding method is a molding method in which a resin material is melt-kneaded using a melt extruder, and the resin material is continuously extruded from a T-die of the melt extruder. For example, the resin material melt-kneaded by the melt extruder is continuously extruded into a belt-shaped resin film through a T-die at the tip of the melt extruder, this continuous resin film is then arranged between subsequent rolls, cooled, and then wound onto a winder. In this way, the resin film is produced. There are no particular limitations on the extruder, and any extruder such as a single-screw extruder or a twin-screw extruder can be used.

[0059] As shown in the examples described later, the SPS resin film of the present invention has good electrical properties (dielectric properties). Furthermore, laminates and metal-clad laminates produced using this SPS resin film are excellent in adhesion to the base heat-resistant resin film (polyimide resin film) and adhesion to a low-roughness metal layer (e.g., low-roughness copper foil) that enables high-speed transmission, have little variation in adhesion, and are excellent in dimensional stability and curl suppression.

[0060] (Laminate) The laminate is a laminate that can be used for printed circuit boards, etc., and can be used in the manufacture of metal-clad laminates (copper-clad laminates (CCL)). The laminate is formed by laminating the SPS resin film of the present invention with a heat-resistant resin film that does not have a melting point below 300°C.

[0061] The laminate is preferably made up of three layers of resin film, and a preferred embodiment of the laminate is a laminate made by laminating a heat-resistant resin film that does not have a melting point below 300°C and the SPS resin film of the present invention on both sides of the heat-resistant resin film.

[0062] <Heat-resistant resin film> From the viewpoint of facilitating lamination with SPS resin films and reducing dielectric loss in the laminate, it is preferable that the heat-resistant resin film does not have a melting point below 300°C. Since heat-resistant resin films do not have a melting point below 300°C, it is preferable that the film be made of a thermosetting resin or a thermoplastic resin with a melting point greater than 300°C. For example, it is preferable that the film be made of a resin selected from polyimide (PI), liquid crystal polymer (LCP), and stretched polyether ether ketone (stretched PEEK). In the present invention, if the heat-resistant resin film is made of a thermoplastic resin and has a melting point greater than 300°C, it is even more preferable that the heat-resistant resin film does not melt at a temperature 30°C above the melting point of the SPS resin film. In other words, in the present invention, it is even more preferable that the melting point of the heat-resistant resin film is higher than the temperature 30°C above the melting point of the SPS resin film. Furthermore, in this invention, by selecting a highly flame-retardant resin as the resin for forming the heat-resistant resin film, and by making the heat-resistant resin film a highly flame-retardant resin film, a laminate with improved flame retardancy can be obtained.

[0063] From the viewpoint of reducing warping of laminates and metal-clad laminates described later, the heat-resistant resin film is preferably a low-CTE resin film with a linear thermal expansion coefficient (CTE) (CTE at 20°C to 140°C) of 50 ppm / °C or less. In this specification, the linear thermal expansion coefficient (CTE) is also referred to as the thermal expansion coefficient, linear thermal expansion rate, or thermal expansion rate.

[0064] The linear thermal expansion coefficient (CTE) of the heat-resistant resin film (CTE at 20°C to 140°C) is preferably close to that of the metal layer (e.g., copper foil film) to which it is bonded as a metal-clad laminate (e.g., copper-clad laminate (CCL)), as described later. This is preferable because it provides better suppression of curling and dimensional stability. For example, a value of 5 to 50 ppm / °C is preferable, and a value of 10 to 30 ppm / °C is preferable.

[0065] The coefficient of linear expansion (CTE) can be determined by thermomechanical analysis (TMA) in accordance with JIS K 7197:1991. For example, it can be determined by using a thermomechanical analyzer (product name: SII / / SS7100, manufactured by Hitachi High-Tech Science Co., Ltd.) in tensile mode, measuring under conditions of a load of 50 mN and a heating rate of 5°C / min in the range from 10°C to 200°C, and then determining the coefficient of linear expansion (ppm / °C) from the slope in the range from 20°C to 140°C.

[0066] Heat-resistant resin films may contain fillers and various additives to impart various functions to the resin film, such as strength, insulation, heat resistance, and adjustment of the coefficient of linear thermal expansion (CTE). The fillers and various additives are as described in the section above (SPS resin film).

[0067] <<Properties of heat-resistant resin film>> The film thickness of the heat-resistant resin film is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 5 μm to 150 μm, more preferably 10 μm to 80 μm, and even more preferably 12 μm to 60 μm. If it is too thick, the dielectric properties may deteriorate, and if it is too thin, curl suppression and dimensional stability may become unstable.

[0068] The surface roughness (Rz) of the heat-resistant resin film is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 1 to 10 μm. If the surface roughness is too low, the film will not wind properly when being wound, and if it is too high, the adhesive strength will be unstable when laminating with the SPS resin film, and problems such as the inclusion of air bubbles are likely to occur. In this specification, surface roughness (Rz) refers to the ten-point average roughness of the film surface. The ten-point average roughness RzJIS can be determined based on JIS B 0601:2013 (ISO 4287:1997 Amd.1:2009). In this specification, the surface roughness of each layer determined by the ten-point average roughness RzJIS is referred to as "surface roughness (Rz)".

[0069] [Measurement of 10-point average roughness RzJIS] The ten-point average roughness RzJIS (μm) of the sheet surface is obtained by measuring the roughness curve of the test specimen using a laser microscope, and then measuring 10 samples each from this roughness curve based on JIS B 0601:2013 (ISO 4287:1997 Amd.1:2009), and calculating the average value.

[0070] The relative permittivity and dielectric loss tangent of the heat-resistant resin film are not particularly limited and can be appropriately selected depending on the purpose. However, for the reason of reducing the transmission loss of electrical signals, it is preferable that the relative permittivity is 3.5 or less and the dielectric loss tangent is 0.025 or less. While a lower dielectric constant is preferable for the heat-resistant resin film, a practically feasible range is, for example, 2.5 to 3.5, and more preferably 3.0 to 3.5. Furthermore, the dielectric loss tangent of the heat-resistant resin film is preferably, for example, 0.001 to 0.025, more preferably 0.001 to 0.01, and even more preferably 0.001 to 0.008.

[0071] Because the dielectric properties of the heat-resistant resin film deteriorate significantly when it absorbs moisture, the water absorption rate of the heat-resistant resin film is preferably, for example, 0 to 2.5%, more preferably 0.01 to 2.0%, even more preferably 0.03 to 1.5%, and particularly preferably 0.05 to 1.2%.

[0072] The surface of the heat-resistant resin film is preferably subjected to one of the following surface treatments selected from corona treatment, plasma treatment, and ultraviolet treatment, for reasons such as improving adhesion.

[0073] <Layer structure of the laminate> Figure 1 is a cross-sectional view showing an example of the structure of the laminate according to the present invention. The laminate 11 comprises an SPS resin film 13, a heat-resistant resin film 12, and an SPS resin film 14, which are laminated in that order.

[0074] By placing a heat-resistant resin film in the middle of the laminate, deterioration of the dimensional stability of the laminate and curling of the laminate can be effectively prevented. The SPS resin film of the present invention is disposed on one or both sides of a heat-resistant resin film. Preferably, the SPS resin film is disposed on both sides of the heat-resistant resin film. By providing the SPS resin film of the present invention, in combination with the heat-resistant resin film, deterioration of the dimensional stability of the laminate and curling of the laminate can be effectively prevented.

[0075] The ratio of the thickness of each SPS resin film (one layer of SPS resin film) placed on both sides of the heat-resistant resin film to the thickness of the heat-resistant resin film (SPS resin film: heat-resistant resin film) is preferably 1:10 to 10:1, more preferably 1:5 to 5:1, and even more preferably 1:3 to 3:1. If the SPS resin film is too thin, the transmission characteristics may deteriorate, and if the SPS resin film is too thick, curling may occur or dimensional stability may deteriorate. Furthermore, it is preferable that the thickness of the SPS resin film be the same as or thinner than the thickness of the heat-resistant resin film. Therefore, the ratio of SPS resin film to heat-resistant resin film is particularly preferable to be 1:2 to 1:1.

[0076] The surface roughness (Rz) of the SPS resin film at the interface between the heat-resistant resin film and the SPS resin film is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 to 10 μm.

[0077] As shown in Figure 1, the SPS resin film is placed on both sides of the heat-resistant resin film 12. The SPS resin film 13 and the SPS resin film 14 may be resin films of the same composition or different compositions, as long as they satisfy the requirements described above.

[0078] (Metal-clad laminate) The metal-clad laminate of the present invention is formed by laminating a metal layer on both or one side of the laminate of the present invention described above.

[0079] The structure consists of an SPS resin film, a heat-resistant resin film, another SPS resin film, and a metal layer, all laminated in this order. Furthermore, the metal-clad laminate of the present invention may have metal layers laminated on both sides of the base film. In this case, the metal-clad laminate is made up of a metal layer, an SPS resin film, a heat-resistant resin film, an SPS resin film, and a metal layer laminated in this order.

[0080] Figure 2 is a cross-sectional view showing an example of the configuration of the metal-clad laminate of the present invention. In Figure 2, an example is shown in which metal layers are laminated on both sides of the laminate. The metal-clad laminate 21 has a metal layer 25, an SPS resin film 23, a heat-resistant resin film 22, an SPS resin film 24, and a metal layer 26, which are laminated in that order.

[0081] There are no particular restrictions on the metals that make up the metal layer, and they can be appropriately selected depending on the purpose. Examples include one selected from the group consisting of nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, and zinc, or an alloy containing one or more of these. Among these, copper and copper-containing alloys are preferred from the viewpoint of shielding properties and economic efficiency. A preferred embodiment of the metal-clad laminate of the present invention is a metal-clad laminate in which a metal foil film is laminated to a laminate. Among these, a copper-clad laminate in which a copper foil film (copper foil film) is laminated to a laminate is more preferred, in which the metal foil is copper foil.

[0082] <Metal layer> A preferred embodiment of the metal layer is a film of metal foil. The type of metal foil is not particularly limited; for example, electrolytic metal foil, rolled metal foil, etc., can be used. Among metal foils, copper foil is more preferable.

[0083] From the viewpoint of ensuring sufficient electrical signal transmission characteristics and enabling a good fine pitch for the circuit pattern, the film thickness of the metal foil is preferably 0.05 μm to 20 μm, and more preferably 0.1 to 15 μm. At the interface between the metal foil film and the SPS resin film, the surface roughness (Rz) of the metal foil film is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less, from the viewpoint of transmission characteristics due to the skin effect.

[0084] <Film thickness of metal-clad laminates> There are no particular restrictions on the film thickness of the metal-clad laminate, and it can be appropriately selected depending on the purpose, but for example, 10 to 300 μm is preferred. If the film thickness of the metal-clad laminate is above the lower limit of the above range, it will have excellent handling properties and ensure strength. If it is below the upper limit of the above range, it will be possible to make it lighter, thinner, shorter, and more flexible.

[0085] (Method of manufacturing a laminate) The method for manufacturing the laminate includes arranging an SPS resin film, a heat-resistant resin film, and another SPS resin film in that order, sandwiching them in a hot press machine or between heating rolls or heating belts, and heat-pressing them to bond the resin films together. The above-mentioned heat-sealing is preferably performed such that, when the melting point of the SPS resin film is Tm (°C), the maximum temperature during heat-sealing is within the temperature range of Tm-30°C to Tm+30°C. Furthermore, the pressure used in heat bonding is preferably 0.2 to 10 MPa, more preferably 1 to 5 MPa, in the case of a heat press or heated belt, and the heat bonding time is preferably 1 to 30 minutes. In the case of a heated roll, a linear pressure of 4 to 60 kN / m and a linear speed of 0.5 to 5.0 m / min are desirable.

[0086] (Method of manufacturing metal-clad laminates) A method for manufacturing a metal-clad laminate includes the steps of placing a metal layer on both or one side of the laminate, heat-pressing it, and bonding the laminate and the metal layer together. Furthermore, the manufacturing method of the metal-clad laminate includes the steps of arranging a metal layer, an SPS resin film, a heat-resistant resin film, and another SPS resin film in that order, sandwiching them in a hot press machine or between heating rolls or heating belts, and heat-pressing them to bond the metal layer to each resin film, or arranging a metal layer, an SPS resin film, a heat-resistant resin film, another SPS resin film, and a metal layer in that order, heat-pressing them together to bond the metal layer to each resin film. The above-mentioned heat-sealing is preferably performed such that, when the melting point of the SPS resin film is Tm (°C), the maximum temperature during heat-sealing is within the temperature range of Tm-30°C to Tm+30°C.

[0087] If the metal-clad laminate is a metal-clad laminate with metal layers on both sides of the laminate as shown in Figure 2, the metal-clad laminate may be manufactured by laminating a metal layer on one side of the laminate using the method described above, and then laminating a metal layer on the other side of the laminate using the same method, or the metal layers on both sides may be laminated together on the laminate to produce a metal-clad laminate with both metal layers in place at once.

[0088] Before forming the metal layer, the surface of the SPS resin film in contact with the metal layer may be surface-treated by corona treatment, plasma treatment, or ultraviolet treatment.

[0089] The laminate of the present invention (especially the double-sided metal-clad laminate) has good electrical properties (dielectric properties), excellent adhesion to the heat-resistant resin film (polyimide resin film) that serves as the base material, and excellent adhesion to a metal layer with low roughness that enables high-speed transmission (for example, low-roughness copper foil), and excellent dimensional stability and curl suppression, making it suitable for use in the manufacture of flexible printed circuit boards (FPCs) and rigid printed circuit boards. For example, a printed circuit board can be manufactured by processing the metal substrate of the metal-clad laminate of the present invention into a transmission circuit (conductor circuit) having a predetermined shape using etching or electroplating methods (semi-additive method (SAP method), modified semi-additive method (MSAP method)). In the manufacturing of printed circuit boards, after forming the transmission circuits, an interlayer insulating film may be formed on the transmission circuits, and then another transmission circuit may be formed on the interlayer insulating film. Alternatively, a solder resist or coverlay film may be laminated on the transmission circuits. [Examples]

[0090] The present invention will be further described below with reference to examples, but the scope of the present invention is not limited to these examples. In the following, parts and % are by mass unless otherwise specified.

[0091] (Coefficient of linear thermal expansion (CTE) (ppm / °C)) The linear thermal expansion coefficient (CTE) was measured in tensile mode using a thermomechanical analyzer (product name: SII / / SS7100, manufactured by Hitachi High-Tech Science Co., Ltd.) under conditions of a load of 50 mN and a heating rate of 5 °C / min, in the range from 10 °C to 200 °C. The linear thermal expansion coefficient (ppm / °C) was determined from the slope in the range from 20 °C to 140 °C. The measurement was taken in the width direction (TD) of the resin film.

[0092] (Melting point (°C)) The melting point was measured in accordance with JIS K 7121. Specifically, approximately 5 mg of the sample was weighed from a melt-extruded resin film and measured using a differential scanning calorimeter (SII Technologies Co., Ltd.: High-sensitivity differential scanning calorimeter X-DSC 7000) at a heating rate of 10°C / min within a measurement temperature range of 20°C to 380°C.

[0093] The materials constituting the resin film used in the following examples and comparative examples are as follows: 90ZC: (Idemitsu Kosan Co., Ltd.) PPO646: (SABIC) Phenolic terminal group content 840 ppm PPO640 (SABIC): Phenol-terminated group content 960 ppm SA120: (SABIC) Phenolic terminal group content 6600 ppm SA9000: (SABIC Corporation) Phenol-terminated group content less than 100 ppm P1500: (Asahi Kasei Corporation) P1083: (Asahi Kasei Corporation) P5051: (Asahi Kasei Corporation) H1043: (Asahi Kasei Corporation) 8006: (Kuraray Co., Ltd.) 2006: (Kuraray Co., Ltd.) Kapton 200LK: (Toray DuPont Co., Ltd.)

[0094] (Example 1) A 50 μm thick polyimide film (PI) (manufactured by Toray DuPont, Kapton 200LK) was prepared. A 25 μm thick SPS resin film was prepared, consisting of the components shown in Table 1-1. The melting point of the SPS resin film was 268°C. A 25 μm thick SPS resin film, with its contact surface treated with corona, was placed on both sides of the polyimide film. Furthermore, copper foil (Fukuda Metal Foil & Powder Industry Co., Ltd., CF-T9DA-SV-12) with a thickness of 12 μm and an Rzjis (Rz) of 0.2 μm was placed on both sides of the outermost surface, and using a hot press machine, it was sandwiched between 1 mm thick stainless steel plates, the hot plate temperature was set to 80°C, and heat compression bonding was started with a surface pressure of 3 MPa. The temperature was increased at a heating rate of 7°C / min while heat compression bonding was performed until the hot plate temperature reached 290°C. Once the temperature reached 290°C, it was cooled to 230°C at a rate of 4°C / min before the pressure was released and the copper-clad laminate (CCL) was removed. The configuration of the laminate having SPS resin and the copper-clad laminate of Example 1 obtained in this manner is shown in Table 1-1 below.

[0095] The copper-clad laminate of Example 1 was evaluated using the following evaluation methods: adhesive strength (bonding strength), peel mode evaluation, dielectric properties, tensile modulus, solder heat resistance test, and curl test. The results are shown in Table 3-1 below.

[0096] (Adhesion strength) For the adhesion strength test, copper-clad laminate (CCL) was cut into 25mm wide test specimens. Referring to JIS Z 0237:2009, the copper-clad laminate (CCL) was fixed to a support (glass support plate) at a peeling speed of 0.3mm / min and a peeling angle of 180°, and the laminate was fixed to a tensile jig. The adhesion strength was measured when the laminate was pulled from the copper-clad laminate (CCL).

[0097] [Evaluation Criteria for Adhesion Strength] ◎ 6N / cm or more ○ 5 N / cm or more and less than 6 N / cm △ 4N / cm or more and less than 5N / cm × Less than 4 N / cm

[0098] (Evaluation of delamination mode) In the adhesion strength test, a copper-clad laminate (CCL) was fixed to a support (glass support plate), the laminate was fixed to a tensioning jig, and after pulling the laminate from the copper-clad laminate (CCL), the layer at which delamination occurred in the copper-clad laminate (CCL) was observed.

[0099] [Evaluation Criteria for Detachment Mode] Cohesive failure: As shown in Figure 3, delamination occurs within the SPS resin film 2. As shown in Figure 4, delamination occurs between the SPS resin film 2 and the metal layer (copper foil) 3 in the Cu-film. Film-PI As shown in Figure 5, delamination occurs between the SPS resin film 2 and the heat-resistant resin film (PI film) 1. Furthermore, among the delamination modes, the cohesive failure delamination mode is preferable to the Cu-film and film-PI delamination modes because it carries a smaller risk of delamination due to the bending angle when mounting as a flexible printed circuit board (FPC).

[0100] (Dielectric properties) A metal layer (copper foil) was placed on both sides of a 25 μm thick SPS resin film. Using a hot press machine, the film was sandwiched between 1 mm thick stainless steel plates, and heat-pressing was started with the hot plate temperature set to 80°C and a surface pressure of 3 MPa. The temperature was then increased at a heating rate of 7°C / min until the hot plate temperature reached 290°C while heat-pressing was being performed. Once the temperature reached 290°C, it was cooled to 230°C at a rate of 4°C / min before the pressure was released to obtain a copper-clad laminate without polyimide film (PI). The copper foil was then removed using an iron chloride aqueous solution to produce an SPS resin film for dielectric property measurement. The dielectric properties (relative permittivity and dielectric loss tangent) of the SPS resin film were measured using an electronic measuring instrument (compact USB vector network analyzer MS46122B: Anritsu Corporation) with the Fabry-Perot method, a type of open-type resonator method, at a frequency of approximately 28 GHz and 23°C × 50 RH%. An open-type resonator (Fabry-Perot resonator Model No. DPS03: Keycom Corporation) was used. The evaluation criteria for dielectric properties are shown below. However, in this embodiment, since the relative permittivity of both the embodiment and the comparative example fell within the desired range, the evaluation criteria shown are those for the dielectric loss tangent.

[0101] [Evaluation Criteria for Dielectric Properties (Dielectric Loss Tangent)] ○ Dielectric loss tangent value is 0.0015 or less. △ Dielectric loss tangent value greater than 0.0015 and less than or equal to 0.002 × Dielectric loss tangent value is greater than 0.002

[0102] (250℃ solder heat resistance test) We observed the state of the fabricated copper-clad laminate after cutting it into 3cm squares and floating it in a solder bath set to 250°C for 1 minute.

[0103] [Evaluation Criteria for 250°C Solder Heat Resistance Test] 〇 No swelling or deformation of the fabricated copper-clad laminate. △ The SPS resin film becomes slightly softer, but there is no blistering or deformation of the copper-clad laminate. × Swelling and deformation occurred in the copper-clad laminate.

[0104] (Curl test) A 150 x 150 mm specimen was cut from the obtained copper-clad laminate (CCL). The copper foil on only one side of the specimen was removed using an iron chloride solution. The specimen was placed on a flat glass plate, and the amount of lift at each of the four corners of the specimen was measured with a ruler. The average value was then calculated.

[0105] [Evaluation Criteria for the Curl Test] 〇 Average of 4 points is 3cm or less △ Average of 4 points is greater than 3cm but less than or equal to 5cm. × The average of the four points is greater than 5cm

[0106] (Examples 2 to 13) Except for changing the type of SPS resin film used in Example 1 as shown in Table 1-1 or Table 1-2 (Tables 1-1 and 1-2 together are also referred to as Table 1), copper-clad laminates of Examples 2 to 13 were prepared in the same manner as in Example 1. Furthermore, when the melting points of the SPS resin films in the copper-clad laminates of Examples 2 to 13 were measured, they were all within the temperature range of 265°C to 270°C. In the SPS resin film (Example 13) using polyphenylene ether SA120 (phenol terminal group content 6600 ppm), some surface defects occurred during molding, with polyphenylene ether aggregates protruding from the film surface, resulting in a reduced yield.

[0107] The copper-clad laminates prepared in Examples 2 to 13 were evaluated using the same method as in Example 1. The evaluation results for the copper-clad laminates of Examples 2 to 13 are shown in Table 3-1 or Table 3-2 (Tables 3-1 and 3-2 together are also referred to as Table 3).

[0108] (Comparative Examples 1-6) Copper-clad laminates of Comparative Examples 1 to 6 were prepared in the same manner as in Example 1, except that the conditions for the type of SPS resin film used were changed as shown in Table 2.

[0109] The copper-clad laminates prepared in Comparative Examples 1 to 6 were evaluated using the same method as in Example 1. Table 4 shows the evaluation results for the copper-clad laminates of Comparative Examples 1 to 6. In the SPS resin film (Comparative Example 1) using polyphenylene ether SA9000 (phenol terminal group content less than 100 ppm), when the SPS resin film was molded, aggregates of polyphenylene ether protruded from the film surface, resulting in appearance defects and a decrease in yield. The number of appearance defects was visually higher than in Example 13.

[0110] [Table 1-1]

[0111] [Table 1-2]

[0112] [Table 2]

[0113] [Table 3-1]

[0114] [Table 3-2]

[0115] [Table 4]

[0116] From the examples, it was confirmed that the metal-clad laminate of the present invention has good electrical properties (dielectric properties), excellent adhesion to the heat-resistant resin film (polyimide resin film) that serves as the base material, excellent adhesion to a metal layer with low roughness that enables high-speed transmission (for example, low-roughness copper foil), and also excellent dimensional stability and curl suppression. [Industrial applicability]

[0117] The metal-clad laminate of the present invention can be suitably used in the manufacture of FPC-related products for electronic devices such as smartphones, mobile phones, optical modules, digital cameras, game consoles, laptop computers, and medical devices. [Explanation of Symbols]

[0118] 1. Heat-resistant resin film (PI film) 2 SPS resin film 3 Metal layer (copper foil) 4. Glass support plate 11 Laminate 12 Heat-resistant resin film 13 SPS resin film 14 SPS resin film 21 Metal-clad laminate 22 Heat-resistant resin film 23 SPS resin film 24 SPS resin film 25 metal layer 26 metal layer

Claims

1. A syndiotactic polystyrene (SPS) resin film further containing polyphenylene ether (PPE) and a rubbery elastic material, The mass ratio of each component in 100 parts by mass of the SPS resin film is: Syndiotactic polystyrene is present in amounts of 65 parts by mass or more and 92 parts by mass or less. The polyphenylene ether is present in amounts of 5 parts by mass or more and less than 30 parts by mass. The rubber-like elastic material is present in an amount of 3 to 20 parts by mass, The aforementioned polyphenylene ether (PPE) has a hydroxyl group (-OH group) at its terminus, An SPS resin film in which the amount of phenol-terminated groups of the polyphenylene ether is 300 ppm or more and 8000 ppm or less.

2. The SPS resin film according to claim 1, wherein the weight-average molecular weight (Mw) of the polyphenylene ether (PPE) is 10,000 to 100,000 g / mol.

3. The SPS resin film according to claim 1, wherein the rubbery elastic body contains a hydrogenated styrene-butadiene-styrene block copolymer (SBS).

4. The SPS resin film according to claim 3, wherein the mass percentage of styrene in the hydrogenated styrene-butadiene-styrene block copolymer (SBS) is 25% by mass or more and 70% by mass or less.

5. The SPS resin film according to claim 3, wherein the melt flow rate (MFR) of the hydrogenated styrene-butadiene-styrene block copolymer (SBS), measured at 230°C and 2.16 kgf, is 0 g / 10 min or more and 10 g / 10 min or less.

6. The SPS resin film according to claim 1, wherein the tensile modulus of the SPS resin film, as measured by a method in accordance with JIS K7127, is 2.4 GPa or more and 3.1 GPa or less.

7. The SPS resin film according to claim 1, obtained by using the SPS resin film described in claim 1 and going through the following a) to d), wherein the tensile modulus of elasticity of the post-heat-pressed SPS resin film, after heat-pressing with copper foil, is measured by a method in accordance with the measurement method of JIS K7127 and is 2.7 GPa or more and 3.6 GPa or less. a) Place copper foil on both sides of the SPS resin film. b) Using a hot press machine, sandwich the material between 1 mm thick stainless steel plates, set the hot plate temperature to 80°C, and begin heat pressing with a surface pressure of 3 MPa. Increase the temperature at a heating rate of 7°C / min until the hot plate temperature reaches 290°C while heat pressing is being performed. c) Once it reaches 290°C, cool it down to 230°C at a rate of 4°C / min, then release the pressure and remove it. d) Etch and remove the copper foil, and extract only the SPS resin film.

8. An SPS resin film according to any one of claims 1 to 7, A laminate formed by laminating a heat-resistant resin film that does not have a melting point below 300°C, A laminate in which the linear thermal expansion coefficient (CTE) of the heat-resistant resin film is 50 ppm / °C or less.

9. A metal-clad laminate, wherein a metal layer is laminated on the SPS resin film on the side opposite to the side on which the heat-resistant resin film is disposed, relative to the laminate according to claim 8, A metal-clad laminate in which the metal layer is copper foil, and the surface roughness (Rz) of the copper foil surface that contacts the SPS resin film is 1 μm or less.

10. A method for manufacturing a metal-clad laminate according to claim 9, The metal layer, the SPS resin film, the heat-resistant resin film, and the SPS resin film are arranged in this order and heat-pressed together, The process includes arranging the metal layer, the SPS resin film, the heat-resistant resin film, the SPS resin film, and the metal layer in this order, and then heat-pressing them together to obtain a metal-clad laminate. A method for manufacturing a metal-clad laminate, wherein the heat-sealing is performed such that, when the melting point of the SPS resin film is Tm (°C), the maximum temperature during heat-sealing is within the temperature range of Tm-30°C to Tm+30°C.

Images