thermosetting marimide resin composition

Abstract

To provide a thermosetting maleimide resin composition that has superior dielectric properties and heat resistance, and exhibits strong adhesion even to copper.SOLUTION: A thermosetting maleimide resin composition includes (A) a modified styrenic elastomer having one or more reactive functional groups in one molecule, (B) a polyphenylene ether resin having a reactive double bond at a molecular chain end, (C) a maleimide compound having one or more dimer acid skeleton-derived hydrocarbon groups in one molecule with a number average molecular weight of 300-10,000, and (D) a reaction initiator.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermosetting maleimide resin composition, as well as uncured and cured resin films, adhesives, encapsulants, and substrates containing the resin composition. [Background technology]

[0002] In recent years, 5G, the next-generation mobile communication system, has become popular, aiming to achieve high speed, large capacity, and low latency communication. To achieve these, materials for high-frequency bands are necessary, and since reducing transmission loss is essential as a noise countermeasure, there is a demand for the development of insulating materials with excellent dielectric properties (low relative permittivity and low dielectric loss tangent). The main properties required include, for example, peel strength, low water absorption, low thermal expansion coefficient, and heat resistance.

[0003] Among these applications, insulating materials with excellent dielectric properties are in demand for substrate applications. For substrates such as rigid and flexible substrates, insulating materials with superior dielectric properties are required, and products such as reactive polyphenylene ether resins (PPE), liquid crystal polymers (LCP), and modified polyimides (MPI) with improved properties are increasingly being used.

[0004] From the perspective of heat resistance, there is a growing demand for high glass transition temperatures (Tg). For substrate applications, a Tg of 150°C or higher is desirable because the reflow process is carried out at high temperatures. Against this backdrop, adhesives with high Tg and excellent adhesive strength and dielectric properties have been reported (Patent Documents 1-4), but most of them are combinations of epoxy resins, other thermosetting resins, and thermoplastic resins. While these compositions have excellent dielectric properties in the frequency range of 10 GHz or less, for 5 GHz and beyond, there is a need for even better dielectric properties in the frequency range of 28 GHz or higher, known as millimeter waves. However, materials that generally exhibit excellent dielectric properties at high frequencies have poor adhesion to metals such as copper foil, and no resin composition exhibiting high Tg, low dielectric properties, and high adhesion to copper foil has been proposed. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2008-248141 [Patent Document 2] Japanese Patent Publication No. 2011-68713 [Patent Document 3] International Publication No. 2016 / 17473 [Patent Document 4] Japanese Patent Publication No. 2016-79354 [Overview of the project] [Problems that the invention aims to solve]

[0006] Accordingly, the present invention aims to provide a thermosetting maleimide resin composition having excellent dielectric properties and heat resistance, and strong adhesion to copper, as well as uncured and cured resin films, adhesives, adhesive films, encapsulants, and substrates containing the same. [Means for solving the problem]

[0007] As a result of diligent research to solve the above problems, the inventors of the present invention have found that the following thermosetting maleimide resin composition can achieve the above objectives, and have completed the present invention. In other words, the present invention provides the following thermosetting maleimide resin compositions, etc.

[0008] <1> (A) Modified styrene-based elastomer having one or more reactive functional groups in one molecule: 100 parts by mass, (B) Polyphenylene ether resin having reactive double bonds at the molecular chain ends: 10 to 200 parts by mass, (C) A maleimide compound having one or more hydrocarbon groups derived from a dimer acid skeleton in one molecule and having a number average molecular weight of 300 to 10,000: 1 to 100 parts by mass, (D) Reaction initiator: 0.01 to 20 parts by mass A thermosetting maleimide resin composition containing [a specific compound]. <2> (A) The styrene-based elastomer of component (A) is a copolymer of styrene and a compound having a carbon-carbon double bond, and contains one or more reactive functional groups selected from amino groups, carboxyl groups, alkenyl groups, methacrylic groups, acrylic groups, epoxy groups, and maleimide groups. <1> The thermosetting maleimide resin composition described in [reference]. <3> The polyphenylene ether resin of component (B) has the structure shown in the following general formula (1). <1> The thermosetting maleimide resin composition described in [reference]. [ka] (In formula (1), X is an organic group having 1 or more carbon atoms, and may contain other atoms such as nitrogen atoms containing oxygen atoms, phosphorus atoms, sulfur atoms, etc., m and p are each 0 or 1, Y is represented by the following formula (2), n and o are each numbers from 0 to 40, and Z is represented by the following formula (3).) [ka] (R1~R in equations (2) and (3)) 12 Each of the following is a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, while Z' is a single bond or a linear hydrocarbon group having 1 to 30 carbon atoms, or a branched or cyclic hydrocarbon group having 3 to 10 carbon atoms. <4> (C) Component has the structure of the following formula (4) <1> The thermosetting maleimide resin composition described in [reference]. [ka] (In formula (4), B is an independent tetravalent organic group having a cyclic structure, and D is an independent divalent hydrocarbon group having 6 to 200 carbon atoms, at least one of which is a hydrocarbon group derived from a dimer acid skeleton. n is between 0 and 100.) <5> The thermosetting maleimide resin composition according to <4>, wherein B in formula (4) is any one of tetravalent organic groups represented by the following structural formulae. [Chemical formula] (In the above structural formula, the bond to which the substituent is not bonded is bonded to the carbonyl carbon forming a cyclic imide structure in formula (4).) <6> The thermosetting maleimide resin composition according to <1>, wherein the component (D) is an organic peroxide. <7> An uncured resin film containing the thermosetting maleimide resin composition according to any one of <1> to <6>. <8> A cured resin film containing a cured product of the thermosetting maleimide resin composition according to any one of <1> to <6>. <9> An adhesive containing the thermosetting maleimide resin composition according to any one of <1> to <6>. <10> An adhesive film containing the thermosetting maleimide resin composition according to any one of <1> to <6>. <11> A prepreg containing the thermosetting maleimide resin composition according to any one of <1> to <6>. <12> A sealing material containing the thermosetting maleimide resin composition according to any one of <1> to <6>. <13> A substrate containing a cured product of the thermosetting maleimide resin composition according to any one of <1> to <6>. [Advantages of the Invention]

[0009] The thermosetting maleimide resin composition of the present invention has excellent dielectric properties and heat resistance, and also exhibits strong adhesion to copper, making it useful as an uncured and cured resin film, adhesive, adhesive film, encapsulant, and substrate. [Modes for carrying out the invention]

[0010] The present invention will be described in more detail below.

[0011] (A) Modified styrene elastomer having one or more reactive functional groups in one molecule The styrene-based elastomer of component (A) used in the present invention primarily contributes to improving the low dielectric properties, heat resistance, and adhesion of the cured composition at high frequencies, as well as improving the flexibility of the film when the composition is formed into a film. The styrene-based elastomer is not particularly limited as long as it is a thermoplastic elastomer having structural units derived from a styrene-based compound and having one or more reactive functional groups in its side chains or terminals, and may also be a thermoplastic elastomer having structural units derived from styrene.

[0012] In the present invention, the styrene-based elastomer is preferably a copolymer of styrene and a compound having a carbon-carbon double bond, and is partially or fully hydrogenated. That is, it is preferably a block copolymer and / or random copolymer in which styrene is the hard segment and the compound having a carbon-carbon double bond is the soft segment. Examples of styrene-based elastomers include styrene / butadiene / styrene block / random copolymer, styrene / isoprene / styrene block / random copolymer, styrene / ethylene / butylene / styrene block / random copolymer, styrene / ethylene / propylene / styrene block / random copolymer, and styrene / butadiene block / random copolymer. Block copolymers are preferred due to their quality stability.

[0013] From the viewpoint of heat resistance, it is preferable to use styrene / ethylene / butylene / styrene block / random copolymers, styrene / ethylene / propylene / styrene block / random copolymers, styrene / butadiene block / random copolymers, etc., in which the double bond of a compound having a carbon-carbon double bond has been eliminated by hydrogenation. Hydrogenation may be partial or complete, but from the viewpoint of heat resistance, complete hydrogenation or a high hydrogenation rate is more preferable.

[0014] In styrene copolymers, the mass ratio of the compound having a styrene / carbon-carbon double bond and the hydrogenated portion thereof is preferably 10 / 90 to 70 / 30, and more preferably 20 / 80 to 67 / 33. If this mass ratio is within this range, a composition with excellent compatibility and dispersibility and stable quality can be obtained. That is, the styrene content by mass in the styrene-based elastomer is preferably 10 to 70% by mass, and more preferably 20 to 67% by mass.

[0015] The styrene-based elastomer is limited to those modified with reactive functional groups. Here, one or more reactive functional groups are preferably selected from amino groups, carboxyl groups, alkenyl groups, methacrylic groups, acrylic groups, epoxy groups, and maleimide groups. The styrene-based elastomer may have modified molecular ends or modified side chains. This allows it to react with components (B) and (C) described later, resulting in a composition with excellent heat resistance. Modification of the styrene-based elastomer can be carried out, for example, by copolymerizing it with an unsaturated carboxylic acid during polymerization. Alternatively, it can be carried out by heating and kneading the styrene-based elastomer and the unsaturated carboxylic acid in the presence of an organic peroxide. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, maleic anhydride, itaconic anhydride, and fumaric anhydride. The method for modifying the styrene-based elastomer is not particularly limited, and known methods can be used. For example, this can be achieved by copolymerizing an unsaturated monomer containing an amino group with a styrene-based elastomer. Alternatively, amine modification can be performed by polymerization using a polymerization initiator containing an amino group.

[0016] The number-average molecular weight (Mn) of component (A) is preferably 10,000 to 300,000, and more preferably 10,000 to 200,000. If the number-average molecular weight is within the above range, the resulting composition will have excellent film properties, excellent compatibility and dispersibility with other components such as component (B) and component (C), and good adhesion. In this specification, the number-average molecular weight refers to the number-average molecular weight measured by gel permeation chromatography (GPC) with polystyrene as the standard substance, under the following conditions.

[0017] [Measurement conditions] Developing solvent: Tetrahydrofuran (THF) Flow rate: 0.35mL / min Detector: Differential refractive index detector (RI) Column: TSK Guardcolumn SuperH-L TSKgel SuperHZ4000(4.6mmI.D.×15cm×1) TSKgel SuperHZ3000(4.6mmI.D.×15cm×1) TSKgel SuperHZ2000 (4.6mmI.D.×15cm×2) (All manufactured by Tosoh Corporation) Column temperature: 40℃ Sample injection volume: 5 μL (THF solution with a concentration of 0.2% by mass)

[0018] (A) The styrene-based elastomer of component (A) may be a commercially available product. Specific examples include the ToughTec series from Asahi Kasei Corporation and the FG series from Kraton Corporation. The composition of the present invention may use one type of styrene-based elastomer alone or a mixture of two or more types. In the thermosetting maleimide resin composition (excluding organic solvents) of the present invention, the amount of component (A) is preferably 30 to 99% by mass, more preferably 40 to 97% by mass, and even more preferably 45 to 95% by mass.

[0019] (B) Polyphenylene ether resin having reactive double bonds at the molecular chain ends The component (B) used in this invention is a polyphenylene ether resin having reactive double bonds at the ends of its molecular chains. Component (B) is used to enhance the heat resistance, dielectric properties, and rigidity of the cured resin composition. Examples of reactive double bonds include alkenyl groups, methacrylic groups, acrylic groups, and maleimide groups.

[0020] (B) Component (B) is preferably one with the structure shown in formula (1) below. [ka] (In formula (1), X is an organic group having 1 or more carbon atoms, and may contain other atoms such as nitrogen atoms containing oxygen atoms, phosphorus atoms, sulfur atoms, etc., m and p are each 0 or 1, Y is represented by the following formula (2), n and o are each numbers from 0 to 40, and Z is represented by the following formula (3).) [ka] (R1~R in equations (2) and (3)) 12 Each of the following is a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, while Z' is a single bond or a linear hydrocarbon group having 1 to 30 carbon atoms, or a branched or cyclic hydrocarbon group having 3 to 10 carbon atoms.

[0021] R1 to R in equations (2) and (3) above 12 Each of these can be independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, but due to the ease of obtaining the raw materials, a hydrogen atom and a methyl group are preferred.

[0022] In formula (3) above, Z' is a single bond or a linear hydrocarbon group having 1 to 30 carbon atoms, a branched hydrocarbon group having 3 to 10 carbon atoms, or a cyclic hydrocarbon group having 3 to 10 carbon atoms. From the viewpoint of ease of obtaining raw materials and heat resistance, a single bond, a linear hydrocarbon group having 1 to 3 carbon atoms, or a branched hydrocarbon group having 3 to 5 carbon atoms is preferred, particularly a divalent aromatic hydrocarbon group. Specifically, a divalent aromatic hydrocarbon group having the following structure can be mentioned. [ka]

[0023] The number-average molecular weight (Mn) of the polyphenylene ether resin, which is component (B), is preferably 500 to 10,000, and particularly preferably 800 to 6,000, based on the number-average molecular weight calculated using a polystyrene standard by gel permeation chromatography (GPC), from the viewpoint of handling properties such as stickiness and compatibility with organic solvents and other components.

[0024] The amount of component (B) is 10 to 200 parts by mass per 100 parts by mass of component (A), preferably 12 to 180 parts by mass, and more preferably 15 to 150 parts by mass. An amount of less than 10 parts by mass is undesirable because it may worsen heat resistance and lower the glass transition temperature, and an amount exceeding 200 parts by mass is undesirable because it may reduce film properties and adhesive strength.

[0025] (C) Maleimide resin The component (C) used in this invention is a maleimide compound having one or more hydrocarbon groups derived from a dimer acid skeleton in one molecule and having a number average molecular weight of 300 to 10,000.

[0026] In this context, dimer acid refers to a liquid dibasic acid mainly composed of a 36-carbon dicarboxylic acid, produced by the dimerization of 18-carbon unsaturated fatty acids derived from natural materials such as vegetable oils. Dimer acid does not have a single skeleton but possesses multiple structures and several isomers exist. Representative dimer acids are classified as linear (a), monocyclic (b), aromatic cyclic (c), and polycyclic (d). In this specification, the dimer acid skeleton refers to a group derived from a dimer amine having a structure in which the carboxyl groups of such a dimer acid are replaced with primary aminomethyl groups. That is, component (A) is preferably a dimer acid skeleton in which, as shown in (a) to (d) below, two carboxyl groups are replaced with methylene groups. Furthermore, in maleimide compounds, hydrocarbon groups derived from the dimer acid skeleton are more preferable if they have a structure in which the carbon-carbon double bond in the hydrocarbon group derived from the dimer acid skeleton is reduced by hydrogenation reaction, from the viewpoint of heat resistance and reliability of the cured product. Generally, dimer acids may contain trimers (trimer acids) due to their use of natural materials such as vegetable oils as raw materials. However, it is preferable that the proportion of dimer acid-derived hydrocarbon groups among the dimer acid and trimer acid-derived hydrocarbon groups is high, for example, 95% by mass or more. This is because it tends to result in superior dielectric properties, reduced viscosity at high temperatures, excellent moldability, and reduced susceptibility to moisture absorption. In this specification, a dimer acid (trimer acid) skeleton refers to a group derived from a dimer amine (trimertriamine) having a structure in which the carboxyl group of such a dimer acid (trimer acid) is replaced with a primary aminomethyl group. [ka]

[0027] Component (A) is preferably a maleimide compound represented by the following formula (4). [ka] (In formula (4), B is an independent tetravalent organic group having a cyclic structure, and D is an independent divalent hydrocarbon group having 6 to 200 carbon atoms, at least one of which is a hydrocarbon group derived from a dimer acid skeleton. n is between 0 and 100.)

[0028] Representative bismaleimide resins of formula (4) include SLK-6895, SLK-1500, and SLK-3000 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0029] Component (C) is a thermosetting resin and reacts with components (A) and (B), resulting in a composition with good heat resistance and mechanical properties, making it highly reliable. In addition, component (C) has divalent hydrocarbon groups derived from a dimer acid skeleton, giving it good dielectric properties and high adhesion. Therefore, the composition exhibits excellent dielectric properties and high adhesion.

[0030] In formula (4) above, B independently represents a tetravalent organic group having a cyclic structure, and is preferably one of the tetravalent organic groups shown in the following structural formulas. [ka] (The bonds in the above structural formula that are not bonded to substituents are bonded to the carbonyl carbon that forms the cyclic imide structure in formula (4).)

[0031] In formula (4) above, D is independently a divalent hydrocarbon group having 6 to 200 carbon atoms, preferably 8 to 100, and more preferably 10 to 50 carbon atoms. Specifically, divalent hydrocarbon groups derived from diamines at both ends, known as dimer amines, are included. Dimer amines are compounds derived from dimers (dimer acids) of unsaturated fatty acids such as oleic acid. Therefore, D is particularly preferably a group in which two carboxyl groups are each substituted with methylene groups in each of the dimer acids shown in (a) to (d) above, and at least one molecule has a skeleton derived from this dimer acid.

[0032] The number-average molecular weight of the maleimide compound of component (C) is preferably 300 to 10,000, and more preferably 500 to 8,000. Furthermore, component (C) may be used alone or in combination of two or more types. In this invention, the number-average molecular weight refers to the number-average molecular weight measured by gel permeation chromatography (GPC) under the above conditions, with polystyrene as the standard substance.

[0033] If a maleimide compound other than the structure of formula (4) is used as component (C), the compatibility with component (A) will decrease, which may cause turbidity or separation when it is formed into a varnish. This may result in unevenness within the composition and variations in the composition's properties.

[0034] The amount of component (C) is 1 to 100 parts by mass, preferably 1 to 75 parts by mass, and more preferably 10 to 50 parts by mass, per 100 parts by mass of component (A). If the amount is less than 1 part by mass, the dielectric properties may deteriorate and the adhesive properties may decrease, which is undesirable. If it exceeds 100 parts by mass, the film properties may decrease and tackiness may occur, which is also undesirable.

[0035] (D) Reaction initiator The reaction initiator of component (D) used in the present invention is added to initiate the crosslinking reaction of components (A), (B), and (C). The reaction initiator is not particularly limited, but it is preferable to use an organic peroxide. Examples of organic peroxides include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and tert-butylcumyl peroxide.

[0036] The amount of component (D) is 0.01 to 20 parts by mass, preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of component (A). An amount of less than 0.01 parts by mass is undesirable because it may reduce curability and worsen dielectric properties, and an amount exceeding 20 parts by mass is undesirable because it may worsen dielectric properties due to residual component (D).

[0037] <Other additives> The thermosetting maleimide resin composition of the present invention may further contain various additives as needed, provided that the effects of the present invention are not impaired. These additives may include, for example, coupling agents such as silane coupling agents and titanate coupling agents, or monomers having (meth)acrylic groups, as adhesive aids.

[0038] (E) Adhesion aid As adhesive aids, coupling agents such as silane coupling agents and titanate coupling agents, or monomers having a (meth)acrylic group can be incorporated. Examples of silane coupling agents include epoxy-functional alkoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; mercapto-functional alkoxysilanes such as γ-mercaptopropyltrimethoxysilane; amine-functional alkoxysilanes such as γ-aminopropyltrimethoxysilane and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane; and methacrylic-functional alkoxysilanes such as 3-methacryloxypropyltrimethoxysilane. Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, isopropyl trioctanoyl titanate, isopropyl dimethacrylate isostearoyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, and isopropyl tri(N-aminoethyl / aminoethyl) titanate. Examples of monomers having a (meth)acrylic group include 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene acrylate, bisphenol A type diacrylate, trimethylolpropane triacrylate, tris(2-acryloxymethyl) isocyanurate, ditrimethylolpropane tetraacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol methacrylate, dipropylene glycol methacrylate, tricyclodecane dimethanol methacrylate, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene methacrylate, bisphenol A type dimethacrylate, trimethylolpropane trimethacrylate, tris(2-methacryloxymethyl) isocyanurate, and ditrimethylolpropane tetramethacrylate.

[0039] The amount of component (E) is preferably 0.01 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of component (A). An amount of less than 0.01 parts by mass is undesirable because it may not improve adhesion, and an amount exceeding 20 parts by mass is undesirable because it may worsen dielectric properties.

[0040] In addition, additives other than component (E) include inorganic fillers such as silica, alumina, and boron nitride; resin powders such as PTFE powder; metal particles such as silver; organopolysiloxanes having reactive functional groups; non-functional silicone oils; thermoplastic resins; thermoplastic elastomers other than styrene-based ones; organic synthetic rubbers; photosensitizers; light stabilizers; polymerization inhibitors; flame retardants; pigments; dyes; and the like. Furthermore, ion trapping agents and the like may be added to improve the electrical properties of the cured product of the thermosetting maleimide resin composition.

[0041] The average particle size and shape of the inorganic filler are not particularly limited, but an average particle size of 0.5 to 50 μm is preferred. The average particle size is determined by the mass-average value D obtained from particle size distribution measurement by laser diffraction. 50 This value is obtained as (or median diameter). The shape is not particularly relevant due to its relationship to the crystal structure.

[0042] The thermosetting maleimide resin composition of the present invention can be produced by mixing component (A), component (B), component (C), and component (D), and other additives as needed.

[0043] The thermosetting maleimide resin composition of the present invention can also be dissolved in an organic solvent and treated as a varnish. By treating the thermosetting maleimide resin composition as a varnish, it becomes easier to mold it into a sheet or film. Any organic solvent that dissolves components (A), (B), and (C) can be used without limitation. Suitable organic solvents include, for example, toluene, xylene, anisole, cyclohexanone, and cyclopentanone. The above organic solvents may be used individually or in mixtures of two or more. The concentration of the thermosetting maleimide resin composition of the present invention in the varnish is preferably 5 to 80% by mass, and more preferably 10 to 75% by mass.

[0044] This thermosetting maleimide resin composition can be suitably used primarily as an adhesive, adhesive film, primer, bonding film and sheet material for substrates, encapsulant, adhesive for coverlay film for flexible printed circuit boards, and flexible flat cable. It can be used without limitations on its method of use or form. For example, it can be used as an uncured resin film, a cured resin film, or an adhesive. Examples of use are given below, but are not limited thereto.

[0045] For example, a thermosetting maleimide resin composition (varnish) dissolved in an organic solvent can be applied to a support sheet, and then heated at a temperature of 80°C or higher, preferably 100°C or higher, for 0.5 to 5 hours to remove the organic solvent and obtain an uncured film or sheet-like composition (uncured resin film). The support sheet can be one of the commonly used types, such as polyolefin resins like polyethylene (PE), polypropylene (PP), and polystyrene (PS); or polyester resins like polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polycarbonate (PC). The surface of these support sheets may also be treated with a release agent. The coating method is not particularly limited, and gap coaters, curtain coaters, roll coaters, and laminators can be used. The thickness of the coating layer is also not particularly limited, but the thickness after solvent removal is in the range of 1 to 100 μm, preferably 3 to 80 μm. Furthermore, a cover film may be used on top of the coating layer.

[0046] Furthermore, a metal foil such as copper foil can be attached to the coating layer and used as a substrate material.

[0047] Furthermore, by applying varnish to the substrate and heating it at a temperature of 80°C or higher, preferably 100°C or higher, for 0.5 to 5 hours to remove the organic solvent, then pressing the object to be bonded to the substrate while heating it, and heating it at a temperature of 130°C or higher, preferably 150°C or higher, for 0.5 to 10 hours, the substrate and the object to be bonded to the substrate can be bonded.

[0048] Methods for applying thermosetting maleimide composition solutions (varnishes) include conventional coating and printing methods. Specifically, coatings such as air doctor coating, bar coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, calender coating, dam coating, dip coating, and die coating, as well as intaglio printing such as gravure printing and stencil printing such as screen printing, can be used.

[0049] Alternatively, a varnished thermosetting maleimide resin composition can be impregnated into glass cloth made of E-glass, low-dielectric glass, or quartz glass, and then the organic solvent is removed to create a semi-cured state for use as a prepreg. Furthermore, rigid substrates can be fabricated by laminating these prepregs or copper foils. [Examples]

[0050] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The components used in the examples and comparative examples are shown below.

[0051] (A) Modified styrene elastomer having one or more reactive functional groups in one molecule (A-1) Hydrogenated styrene / ethylene / butylene / styrene block copolymer with 30% styrene content (ToughTec MP10: manufactured by Asahi Kasei Corporation) (A-2) Carboxylic acid-modified styrene / ethylene / butylene / styrene block copolymer, styrene content 30% by mass (ToughTec M1913: manufactured by Asahi Kasei Corporation) (A'-1) Hydrogenated styrene / ethylene / butylene / styrene block copolymer, styrene content 30% by mass (ToughTec H1041: manufactured by Asahi Kasei Corporation, for comparative example)

[0052] (B) Polyphenylene ether resin having a reactive double bond at the molecular chain end (B-1) Terminally methacrylated polyphenylene ether (SA9000, manufactured by SABIC Co., Ltd.) (B-2) Terminally styrenated polyphenylene ether (OPE-2St-1200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) (B-3) Terminally styrenated polyphenylene ether (OPE-2St-2200, manufactured by Mitsubishi Gas Chemical Co., Ltd.)

[0053] (C) Maleimide resin (C-1): Bismaleimide compound represented by the following formula (SLK-6895, manufactured by Shin-Etsu Chemical Co., Ltd., number average molecular weight 1000)

Chemical formula

Chemical formula

Chemical formula

[0054] (D) Reaction initiator (D-1): Dicumyl peroxide (Percumyl D: Manufactured by NOF Corporation)

[0055] (E) Adhesion aid (E-1): 3-Methacryloxypropyltrimethoxysilane (KBM-503: Manufactured by Shin-Etsu Chemical Co., Ltd.)

[0056] (F) Inorganic filler (F-1): Molten spherical silica (SO-25R, manufactured by Admatex Co., Ltd., average particle size 0.5 μm) treated with methacrylic group-modified silane coupling agent (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0057] <Varnish preparation> Using the formulations shown in Table 1, each component was placed in a 500 mL four-necked flask equipped with a Liebig condenser and a stirring device, and stirred at 50°C for 2 hours to obtain a varnish-like resin composition. [Table 1]

[0058] <Preparation of uncured film> A varnish-like thermosetting maleimide resin composition was applied to a 38 μm thick PET film using a roller coater to a dry thickness of 50 μm, and dried at 120°C for 10 minutes to obtain an uncured resin film.

[0059] <Handling properties of uncured resin film> The aforementioned uncured resin film was visually inspected to see if it cracked or broke when folded 90 degrees under conditions of 25°C. A circle (○) was used if no cracks, breaks, or tacks were observed, while a cross (×) was used if even slight cracks, breaks, or tacks were detected.

[0060] <Relative permittivity, dielectric loss tangent> The uncured resin film was cured at 180°C for 2 hours, and the resulting resin film was cut to prepare 60mm x 60mm test specimens. The relative permittivity and dielectric loss tangent of the obtained test specimens were measured at 25°C and 28GHz using an SPDR dielectric resonator (MS46122B, manufactured by Anritsu Corporation).

[0061] <Heat resistance> The cured resin film produced using the above process was stored at 150°C for 500 hours, and then its dielectric properties were measured at 25°C and 28 GHz using the above apparatus. The rate of change was calculated from the initial dielectric loss tangent value and the dielectric loss tangent value after 500 hours of storage, and the heat resistance was evaluated.

[0062] <Peel strength> A microscope slide measuring 75 mm in length, 25 mm in width, and 1.0 mm in thickness was prepared. The resin composition side of the uncured resin film with PET film attached, without the PET substrate, was placed on one surface of the slide, and lamination was performed at 120°C, 0.3 MPa pressure, and 60 seconds. After lamination, the PET substrate was peeled off, and an 18 μm thick copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., Ra 0.6 μm) was placed on the resin composition side, and lamination was performed at 120°C, 0.3 MPa pressure, and 60 seconds. After lamination, the test specimen was prepared by curing at 180°C for 2 hours.

[0063] To evaluate adhesion, the 90° peel strength (kN / m) when peeling each adhesive test specimen from the copper foil was measured in accordance with JIS-C-6481 "Test Method for Copper-Clad Laminates for Printed Wiring Boards" at a temperature of 23°C and a tensile speed of 50 mm / min.

[0064] <Glass transition temperature> The aforementioned uncured resin film was cured at 180°C for 2 hours. After the cured film had cooled sufficiently, the glass transition temperature (Tg) was measured using a TA Instruments DMA-800.

[0065] The evaluation results are shown in Table 2. [Table 2]

[0066] The results in Table 2 confirm that the uncured resin films in Examples 1-12 showed no cracks or breakage. Comparative Examples 1 and 5 also showed no cracks, similar to the examples. On the other hand, Comparative Examples 2-4 showed the occurrence of cracks and tack.

[0067] From the above results, it was confirmed that the thermosetting maleimide resin composition of the present invention has film properties, excellent dielectric properties of the cured product, high heat resistance and strong adhesion to metals, and is therefore useful as an insulating material suitable for substrate applications.

Claims

1. (A) Modified styrene-based elastomer having one or more reactive functional groups in one molecule: 100 parts by mass, (B) Polyphenylene ether resin having reactive double bonds at the molecular chain ends: 10 to 200 parts by mass, (C) A maleimide compound having one or more hydrocarbon groups derived from a dimer acid skeleton in one molecule and having a number average molecular weight of 300 to 10,000: 1 to 100 parts by mass, (D) Reaction initiator: 0.01 to 20 parts by mass A thermosetting maleimide resin composition containing [a specific compound].

2. The thermosetting maleimide resin composition according to claim 1, wherein the styrene-based elastomer of component (A) is a copolymer of styrene and a compound having a carbon-carbon double bond, and contains one or more reactive functional groups selected from an amino group, a carboxyl group, an alkenyl group, a methacrylic group, an acrylic group, an epoxy group, and a maleimide group.

3. The thermosetting maleimide resin composition according to claim 1, wherein the polyphenylene ether resin of component (B) has a structure represented by the following general formula (1). 【Chemistry 1】 (In formula (1), X is an organic group having one or more carbon atoms, which may contain oxygen, nitrogen, phosphorus, and sulfur atoms; m and p are each 1; Y is represented by the following formula (2); n and o are each numbers from 0 to 40; and Z is represented by the following formula (3).) 【Chemistry 2】 (R in equations (2) and (3)) 1 ~R 12 Each of the following is a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, and Z' is a single bond or a linear hydrocarbon group having 1 to 30 carbon atoms, or a branched or cyclic hydrocarbon group having 3 to 10 carbon atoms.

4. The thermosetting maleimide resin composition according to claim 1, wherein component (C) has the structure of the following formula (4). 【Transformation 3】 (In formula (4), B is an independent tetravalent organic group having a cyclic structure, and D is an independent divalent hydrocarbon group having 6 to 200 carbon atoms, at least one of which is a hydrocarbon group derived from a dimer acid skeleton. n is between 0 and 100.)

5. The thermosetting maleimide resin composition according to claim 4, wherein B in formula (4) is any of the tetravalent organic groups shown in the following structural formula. 【Chemistry 4】 (The bonds in the above structural formula that are not bonded to substituents are bonded to the carbonyl carbon that forms the cyclic imide structure in formula (4).)

6. The thermosetting maleimide resin composition according to claim 1, wherein the (D) component is an organic peroxide.

7. An uncured resin film containing the thermosetting maleimide resin composition according to any one of claims 1 to 6.

8. A cured resin film containing a cured product of the thermosetting maleimide resin composition according to any one of claims 1 to 6.

9. An adhesive containing the thermosetting maleimide resin composition according to any one of claims 1 to 6.

10. An adhesive film containing the thermosetting maleimide resin composition according to any one of claims 1 to 6.

11. A prepreg containing the thermosetting maleimide resin composition according to any one of claims 1 to 6.

12. A sealing material containing the thermosetting maleimide resin composition according to any one of claims 1 to 6.

13. A substrate containing a cured product of the thermosetting maleimide resin composition according to any one of claims 1 to 6.

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