Resin composition, dry film and cured product

Abstract

[Problem] To provide: a resin composition which is capable of suppressing expansion of an insulating layer even when cured in an air atmosphere; a dry film provided with a resin layer formed from the resin composition; and a cured product obtained using the resin composition or the resin layer of the dry film. [Solution] The resin composition contains (A) a resin having a radically polymerizable functional group and (B) a radical polymerization initiator, and when the glass transition temperature (Tg) of the (A) resin is X DEG C and the temperature of the heating peak top when the (B) radical polymerization initiator is heated from 25 DEG C to 300 DEG C at a rate of 5 DEG C / min by differential scanning calorimetry (DSC) is Y DEG C, X DEG C represents the glass transition temperature (Tg) of the (A) resin and Y DEG C represents the temperature of the heating peak top. (X-18) < = Y < = 250.

Description

Technical Field

[0001] The present invention relates to a resin composition, a dry film and a cured product. Background Art

[0002] In recent years, with the widespread use of high-capacity, high-speed communications represented by the fifth-generation communication system (5G) and millimeter-wave radar for automotive ADAS (Advanced Driver Assistance Systems), the frequency of signals in electronic devices has been increasing.

[0003] In the printed wiring substrate built into such electronic devices, a curable resin composition with epoxy resin as a main component is used as an interlayer insulating material. The relative dielectric constant (Dk) and dielectric tangent (Df) of the cured product formed by the composition are high, which increases the signal transmission loss in the high-frequency band, resulting in problems such as signal attenuation and heating. Therefore, polyphenylene ether with excellent low dielectric properties has attracted attention.

[0004] Non-Patent Document 1 proposes obtaining polyphenylene ether having improved heat resistance by introducing an allyl group into the molecule of polyphenylene ether to form a thermosetting resin.

[0005] Prior art literature

[0006] Non-patent literature

[0007] Non-patent literature 1J.Nunoshige, H.Akahoshi, Y.Shibasaki, M.Ueda, J.Polym.Sci.Part.A:Polym.Chem.2008,46,5278-5282. Summary of the Invention

[0008] Problems to be solved by the present invention

[0009] When a resin composition using such polyphenylene ether is cured by a radical reaction and used as an interlayer insulating material, the curing is generally performed under an inert gas atmosphere such as nitrogen to prevent the curing reaction from being inhibited by oxygen.

[0010] On the other hand, from the viewpoint of equipment and safety, it is required to replace inert gases such as nitrogen and solidify to obtain a cured product under an atmospheric atmosphere. However, if a resin composition using polyphenylene ether is cured under an atmospheric atmosphere, the curing reaction is difficult to proceed, and plating expansion (expansion) occurs between the substrate and the insulating (cured product) layer. Plating expansion refers to a phenomenon in which a part of the insulating layer is separated from the substrate during the plating process. Therefore, when curing under an atmospheric atmosphere, it is difficult to obtain a cured product with the same quality as when curing under an inert gas atmosphere.

[0011] Therefore, the technical problem to be solved by the present invention is to provide a resin composition that can suppress the expansion of an insulating layer even when cured in an atmospheric atmosphere; a dry film having a resin layer formed from the resin composition; and a cured product obtained using the resin composition or the resin layer of the dry film.

[0012] Means of solving the problem

[0013] One embodiment of the present invention is a resin composition. The resin composition includes (A) a resin and (B) a free radical polymerization initiator, wherein the resin (A) has a free radical polymerizable functional group, and when the glass transition temperature (Tg) of the resin (A) is X°C and the temperature of the exothermic peak of the free radical polymerization initiator (B) when heated from 25°C to 300°C at a rate of 5°C / min by differential scanning calorimetry (DSC) is Y°C, the resin composition satisfies (X-18)≤Y≤250.

[0014] The resin composition of the above embodiment preferably contains (C) a low-molecular-weight component having a radically polymerizable functional group and a molecular weight of 1000 or less.

[0015] In the resin composition of the above embodiment, preferably, the radical polymerizable functional group of the resin (A) is at least one selected from the group consisting of a vinyl group, an allyl group, and a maleimide group.

[0016] In the resin composition of the above embodiment, preferably, the (B) radical polymerization initiator includes a peroxide structure (excluding a structure represented by -OOH) or an oxime ester structure.

[0017] In the resin composition of the above embodiment, it is preferred that the resin (A) is a branched polyphenylene ether resin.

[0018] In the resin composition of the above embodiment, preferably, the weight average molecular weight Mw of the resin (A) is 2000 or greater.

[0019] Another embodiment of the present invention is a dry film having a resin layer formed from the resin composition of the above embodiment.

[0020] Another embodiment of the present invention is a cured product obtained by using the resin composition of the above embodiment or the resin layer of the dry film of the above embodiment.

[0021] In the cured product of the above embodiment, it is preferable that the cured product is obtained by curing the resin composition or the resin layer in an air atmosphere.

[0022] Effects of the Invention

[0023] The present invention provides a resin composition capable of suppressing expansion of an insulating layer even when cured in an air atmosphere; a dry film having a resin layer formed from the resin composition; and a cured product obtained using the resin composition or the resin layer of the dry film. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present invention will be described in detail. In addition, in this specification, the expression "a to b" in the description of a numerical range means a or more and b or less unless otherwise specified.

[0025] In the case where isomers exist for the described compounds, all possible isomers are contemplated for use in the present invention unless otherwise stated.

[0026] In this specification, phenols used as raw materials of polyphenylene ether (PPE) and capable of becoming constituent units of polyphenylene ether are collectively referred to as "raw material phenols."

[0027] In the present specification, when describing the raw material phenols, when referring to the "ortho position" or "para position" or the like, unless otherwise specified, the position of the phenolic hydroxyl group is used as the reference (proper position).

[0028] In this specification, when simply expressed as "ortho position" etc., it means "at least one of the ortho position" etc. Therefore, as long as no particular contradiction arises, when simply expressed as "ortho position", it can be interpreted as indicating either one of the ortho positions, and can also be interpreted as indicating both ortho positions.

[0029] In this specification, polyphenylene ether in which some or all of its functional groups (e.g., hydroxyl groups) are modified may be simply referred to as "polyphenylene ether." Therefore, when referred to as "polyphenylene ether," both unmodified and modified polyphenylene ethers are included unless there is any particular contradiction.

[0030] In this specification, monohydric phenols are mainly disclosed as raw material phenols, but polyhydric phenols may also be used as raw material phenols within a range not hindering the effects of the present invention.

[0031] In this specification, when the upper limit and the lower limit of a numerical range are described separately, all combinations of the lower limit and the upper limit are substantially described within the range that does not conflict.

[0032] In this specification, the solid content is used to mean a non-volatile component (components other than volatile components such as a solvent).

[0033] In this specification, "resin" refers to a compound having a molecular weight distribution (Mw / Mn) exceeding 1. Mw represents the weight average molecular weight, and Mn represents the number average molecular weight. In addition, "low molecular weight component" refers to a compound composed of a single molecule that does not have a molecular weight distribution.

[0034] In this specification, the components contained in the resin composition and the components contained in the dried coating film of the resin composition, that is, the resin layer, are sometimes described without distinction.

[0035] 1. Resin composition

[0036] The resin composition of this embodiment contains (A) a resin, (B) a radical polymerization initiator, and (C) a low molecular weight component. In addition, the resin composition may contain other components within a range that does not hinder the effects of the present invention.

[0037] The resin composition of this embodiment satisfies the following relationship: (X-18)≤Y≤250, when the glass transition temperature (Tg) of the resin (A) described later is X°C and the temperature of the exothermic peak top of the radical polymerization initiator (B) described later when the temperature is raised from 25°C to 300°C at a rate of 5°C / min by differential scanning calorimetry (DSC) is Y°C. The components contained in the resin composition are described in detail below.

[0038] 1-1. (A) Resin

[0039] The (A) resin is not particularly limited as long as it is a resin (polymer) having a radical polymerizable functional group and undergoing polymerization reaction by a radical polymerization initiator.

[0040] The free radical polymerizable functional group is, for example, preferably an ethylenically unsaturated group having a carbon-carbon double bond. The ethylenically unsaturated group is preferably one or more selected from the group consisting of an acrylic group, a methacrylic group, a styryl group, an olefin group (vinyl, allyl, propenyl, etc.), and a maleimide group. Among the above-mentioned ethylenically unsaturated groups, the free radical polymerizable functional group is more preferably one or more selected from the group consisting of a vinyl group, an allyl group, and a maleimide group from the viewpoint of dielectric properties. The (A) resin may have one or more free radical polymerizable functional groups.

[0041] The number of radical polymerizable functional groups in the molecule of the resin (A) is not particularly limited as long as it is one or more, and is preferably two or more from the viewpoint of mechanical properties.

[0042] The resin (A) is not particularly limited. Examples of the resin include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyamide resins; polyamide-imide resins; polyphenylene sulfide resins; polyetheretherketone resins; polyethersulfone resins; polycarbonate resins; polyetherimide resins; epoxy resins; phenolic resins; phenoxy resins; glass-epoxy resins; polyphenylene ether resins (PPE); acrylic resins; silicone resins; polyolefin resins such as polyethylene and polypropylene; polycycloolefin resins such as polynorbornene; and triazine resins such as melamine. These resins may be used alone or in combination of two or more.

[0043] From the viewpoint of achieving an appropriate glass transition temperature (Tg), the resin (A) is preferably a polyphenylene ether resin. The main chain structure of the polyphenylene ether resin may be either a linear or branched structure.

[0044] Polyphenylene ether resins having a branched structure (also referred to as branched polyphenylene ether resins or branched PPE) are excellent in solubility in solvents and compatibility or reactivity with the components of the resin composition. Therefore, the resin (A) is preferably a branched polyphenylene ether resin.

[0045] Branched polyphenylene ether resins are polyphenylene ethers produced from phenolic raw materials, which include phenols having hydrogen atoms at the ortho and para positions. Since these phenols have hydrogen atoms at the ortho position, ether bonds can form not only at the ortho and para positions but also at the ortho position during oxidative polymerization with the phenols. Consequently, polyphenylene ethers produced using these phenols as raw materials can have a branched structure.

[0046] The glass transition temperature (Tg) of the resin (A) is preferably 100°C or higher, 150°C or higher, 180°C or higher, and preferably 230°C or lower, 220°C or lower, 200°C or lower, etc. The glass transition temperature (Tg) can be measured by differential scanning calorimetry (DSC). If the glass transition temperature of the resin (A) is within the above range, a cured product having excellent mechanical properties, heat resistance, etc. can be obtained.

[0047] The weight average molecular weight (Mw) of the (A) resin is preferably 1000 or more, 1500 or more, 2000 or more, and preferably 150,000 or less, 100,000 or less, 80,000 or less. The weight average molecular weight (Mw) can be obtained based on the standard polystyrene conversion value obtained by gel permeation chromatography (GPC). For the GPC measuring device, a high-speed GPC device (HLC-8320GPC, manufactured by Tosoh Corporation) can be used as a measuring device, chloroform can be used as an eluent, and an RI detector can be used as a detector to measure.

[0048] The resin (A) may be a mixture of two or more polyphenylene ethers having different kinds of raw material phenols.

[0049] The amount of the resin (A) added is preferably 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 3% by mass or more, 5% by mass or more, etc., based on the total solid content of the resin composition, and is preferably 40% by mass or less, 35% by mass or less, 30% by mass or less, 25% by mass or less, etc.

[0050] 1-2. (B) Radical Polymerization Initiator

[0051] The (B) radical polymerization initiator is a compound that generates free radicals upon irradiation with heat or light such as ultraviolet rays. The (B) radical polymerization initiator can be a thermal polymerization initiator (thermal radical initiator) that generates free radicals upon irradiation with heat, a photopolymerization initiator (photoradical initiator) that generates free radicals upon irradiation with light, or a photothermal bi-initiator that generates free radicals upon both light and heat, depending on the intended use of the resin composition.

[0052] The radical polymerization initiator will be described in detail below. In addition, there are cases where examples of a thermal polymerization initiator and a photothermal biinitiator, or a photopolymerization initiator and a photothermal biinitiator are repeated.

[0053] <Thermal Polymerization Initiator>

[0054] As the thermal polymerization initiator, a peroxide containing a peroxy structure (-OO-) is preferred. Examples of the peroxide include methyl ethyl ketone peroxide, methyl acetoacetic acid peroxide, acetyl peroxide, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-butyl hydroperoxide, tert-butyl hydroperoxide, diisopropylbenzene peroxide, 2,5-dimethylhexane-2,5-dihydroperoxide, -2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)-3-butene, acetyl peroxide, octyl peroxide, dodecyl peroxide, benzoyl peroxide, m-methyl peroxytoluene, diisopropyl peroxydicarbonate, tert-butyl peroxybenzoate, di-tert-butyl peroxide, tert-butyl peroxyisopropyl monocarbonate, α,α'-bis(tert-butylperoxy-m-isopropyl)benzene, etc.

[0055] Among these, peroxides having a one-minute half-life temperature of 130°C to 180°C are preferred from the viewpoints of ease of handling and reactivity. Since such peroxides have a relatively high reaction initiation temperature, curing is less likely to be accelerated at times when curing is not necessary (e.g., during drying), thereby not reducing the storage stability of the polyphenylene ether resin composition. Furthermore, due to their low volatility, they do not volatilize during drying or storage, resulting in excellent stability.

[0056] As the thermal polymerization initiator, azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2'-dimethylvaleronitrile) may also be used.

[0057] They can be used alone or in combination.

[0058] <Photopolymerization Initiator>

[0059] Examples of the photopolymerization initiator include those having an oxime ester structure, an α-aminoacetophenone structure, a hydroxyacetophenone structure, an acylphosphine oxide structure, a benzoin structure, a benzophenone structure, an acetophenone structure, a thioxanthone structure, an anthraquinone structure, a ketal structure, a benzoate structure, and a thioxanthone structure. Among these, those having an oxime ester structure are preferred.

[0060] Examples of substances containing an oxime ester structure include 2-(benzoyloxyimino)-1-[4-(phenylthio)phenyl]octan-1-one (OXE01), [1-[9-ethyl-6-(2-methylbenzoyl)carbazol-3-yl]ethylideneamino]acetate, and ethyl ketone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetoxime) (OXE02).

[0061] They can be used alone or in combination.

[0062] <Photothermal dual initiator>

[0063] As the photothermal diinitiator, a peroxide containing a peroxy structure (—OO—) is preferred, and examples thereof include 3,3′,4,4′-tetrakis(tert-butylperoxycarbonyl)benzophenone and 2-(1-tert-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one.

[0064] Among the above-mentioned substances, the radical polymerization initiator (B) preferably contains a peroxide structure (excluding structures represented by -OOH) or an oxime ester structure. Furthermore, among the above-mentioned substances, the radical polymerization initiator (B) is preferably a compound with higher solvent solubility, and for example, a compound having a structure containing a heteroatom is more preferable.

[0065] More specifically, 2-(1-tert-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one and the commercially available product Irgacure OXE02 (manufactured by BASF Japan Ltd.) are more preferred, and 2-(1-tert-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one is particularly preferred. By using 2-(1-tert-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one as the radical polymerization initiator (B), the stability of the resin composition can be ensured even under white light.

[0066] When the temperature of the exothermic peak top of the (B) radical polymerization initiator when heated from 25°C to 300°C at a rate of 5°C / min by differential scanning calorimetry (DSC) is defined as Y°C, and when the glass transition temperature (Tg) of the (A) resin is defined as X°C, Y satisfies (X-18) ≤ Y ≤ 250. Specifically, Y is preferably 82°C or higher, 132°C or higher, 162°C or higher, and may be 250°C or lower.

[0067] If Y is within the above range, the stability of the radical polymerization initiator (B) can be maintained up to a value relatively close to the glass transition temperature (Tg) X of the resin (A), thereby increasing the crosslinking density during curing of the resin composition and improving the breaking strength. Furthermore, plating expansion can be suppressed even when the resin composition is cured in an air atmosphere.

[0068] The amount of the radical polymerization initiator (B) added may be 0.01 to 15 parts by mass relative to 100 parts by mass of the solid content of the resin (A).

[0069] 1-3. (C) Low molecular weight components

[0070] The low molecular weight component (C) of this embodiment has a radical polymerizable functional group and has a molecular weight of not more than 1000. Since the radical polymerizable functional group is the same as that described in "1-1. (A) Resin", its description is omitted here.

[0071] The low molecular weight component (C) is a compound that undergoes a curing reaction with the resin (A), and preferably has good compatibility with the resin (A). Examples thereof include: polyfunctional vinyl compounds such as divinylbenzene, divinylnaphthalene, and divinylbiphenyl; vinylbenzyl ether compounds synthesized by reacting phenol with vinyl chloride benzyl; allyl ether compounds synthesized by reacting styrene monomer, phenol, and allyl chloride; (meth)acrylate compounds (methacrylate compounds and acrylate compounds); and trialkenyl isocyanurate.

[0072] Among them, trialenyl isocyanurate is preferred, and specifically triallyl isocyanurate (hereinafter referred to as TAIC (registered trademark)) and triallyl urate (hereinafter referred to as TAC) are preferred, from the viewpoint of particularly good compatibility with the resin (A) and improved low dielectric properties and heat resistance of the cured product. The low molecular weight component (C) can be used alone or in combination of two or more.

[0073] The molecular weight of the low molecular weight component (C) is preferably 1000 or less, more preferably 500 or less, and further preferably 400 or less from the viewpoint of crosslinking density. The number of functional groups of the low molecular weight component (C) is preferably 2 to 4 from the viewpoint of mechanical properties of the resulting cured product. The melting point of the low molecular weight component (C) is preferably 80°C or less from the viewpoint of melt viscosity. By including the low molecular weight component (C), when a dry film described later is produced from the resin composition, the warping of the dry film can be reduced. In addition, even when the resin composition is cured in an atmospheric atmosphere, plating expansion can be suppressed.

[0074] The amount of the low molecular weight component (C) added may be 10 to 200 parts by mass, 50 to 150 parts by mass, or the like relative to 100 parts by mass of the solid content of the resin (A).

[0075] 1-4. Other ingredients

[0076] As other components, known components may be included, such as fillers (in addition to inorganic fillers, organic fillers such as PTFE powder may also be used), flame retardant enhancers (phosphorus compounds, etc.), cellulose nanofibers, cyanate resins, epoxy resins, phenol novolac resins, elastomers, dispersants, curing accelerators, cross-linking curing agents (cross-linking agents), adhesion imparting agents, solvents and other components.

[0077] <Inorganic filler>

[0078] As inorganic fillers, metal oxides such as aluminum oxide and titanium oxide; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; clay minerals such as talc and mica; fillers having a perovskite crystal structure such as barium titanate and strontium titanate; silicon dioxide, boron nitride, aluminum borate, barium sulfate, calcium carbonate, etc. can be used.

[0079] Among the above-mentioned inorganic fillers, silica improves the film-forming properties of the resin composition and can achieve a high level of low dielectric tangent and low thermal expansion.

[0080] The average particle size of silica is preferably 0.02 to 10 μm, more preferably 0.02 to 3 μm. The average particle size here can be determined as the median particle size (d50, volume basis) obtained from the cumulative distribution of the particle size distribution measured using a commercially available laser diffraction / scattering particle size distribution analyzer. The average particle size of silica refers to the value measured as described above for the powdered material before the resin composition is prepared (pre-stirred and mixed).

[0081] Silica with different average particle sizes may be used together. For example, from the perspective of achieving high silica filling, silica with an average particle size of 1 μm or more and nano-scale microsilica with an average particle size of less than 1 μm may be used together.

[0082] Silica can also be surface-treated with a coupling agent. Surface treatment with a silane coupling agent can improve dispersibility with polyphenylene ether and enhance compatibility with organic solvents.

[0083] As silane coupling agents, for example, epoxy silane coupling agents, mercapto silane coupling agents, vinyl silane coupling agents, etc. can be used. As epoxy silane coupling agents, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, etc. can be used. As mercapto silane coupling agents, for example, γ-mercaptopropyltriethoxysilane, etc. can be used. As vinyl silane coupling agents, for example, vinyltriethoxysilane, etc. can be used.

[0084] The amount of the silane coupling agent used can be, for example, 0.1 to 5 parts by mass or 0.5 to 3 parts by mass relative to 100 parts by mass of silica.

[0085] The amount of filler such as silica added can be 50 to 400 parts by mass or 100 to 400 parts by mass relative to 100 parts by mass of the solid content of the resin (A). Alternatively, the amount of filler such as silica added can be 30 to 80% by mass based on the total solid content of the resin composition. By adjusting the amount of filler added within the above range, when a dry film described later is produced from the resin composition, warping of the dry film can be reduced. In addition, even when the resin composition is cured in an atmospheric atmosphere, plating expansion can be suppressed.

[0086] <Elastomer>

[0087] The inclusion of an elastomer can improve the rebound resilience of the dry film and cured product described below. Examples of the elastomer include diene synthetic rubbers such as polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, polychloroprene rubber, nitrile rubber, and ethylene-propylene rubber; non-diene synthetic rubbers such as ethylene-propylene rubber, butyl rubber, acrylic rubber, polyurethane rubber, fluororubber, silicone rubber, and epichlorohydrin rubber; natural rubber, styrene elastomers, olefin elastomers, polyurethane elastomers, polyester elastomers, polyamide elastomers, acrylic elastomers, and silicone elastomers.

[0088] From the viewpoint of compatibility with (A) resin and dielectric properties, at least a portion of the elastomer is preferably a styrene-based elastomer. As styrene-based elastomers, styrene-butadiene-styrene block copolymers, styrene-butadiene copolymers such as styrene-butadiene-styrene block copolymers; styrene-isoprene copolymers such as styrene-isoprene-styrene block copolymers; styrene-ethylene-butylene-styrene block copolymers, styrene-ethylene-propylene-styrene block copolymers, etc. Since the dielectric properties of the cured product obtained are particularly good, it is preferably a styrene-based elastomer that does not have unsaturated carbon bonds such as styrene-ethylene-butylene-styrene block copolymers.

[0089] The content of the styrene block in the styrene-based elastomer is preferably 10 to 70 mass%, 30 to 60 mass%, or 40 to 50 mass%. 1 The integration ratio of the spectrum measured by H-NMR was determined.

[0090] Here, the raw material monomer of the styrene-based elastomer includes not only styrene but also styrene derivatives such as α-methylstyrene, 3-methylstyrene, 4-propylstyrene, and 4-cyclohexylstyrene.

[0091] The proportion of the styrene elastomer in 100% by weight of the elastomer can be, for example, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass.

[0092] The elastomer may be modified with (meth)acrylic acid, maleic acid, anhydrides or esters thereof, etc. Alternatively, water may be added to the residual unsaturated bonds of the diene elastomer.

[0093] The number average molecular weight of the elastomer may be 1000 to 150000. When the number average molecular weight is at least the lower limit, low thermal expansion is excellent, while when it is at most the upper limit, compatibility with other components is excellent.

[0094] The amount of the elastomer added to the resin composition may be 10 to 300 parts by mass relative to 100 parts by mass of the solid content of the resin (A). Alternatively, the amount of the elastomer added may be 3 to 65% by mass based on the total solid content of the resin composition. Within this range, a good balance of tensile properties, adhesion, and heat resistance can be achieved.

[0095] Solvents

[0096] The resin composition of the present invention is usually provided or used in a state where the (A) resin is dissolved in a solvent.

[0097] As an example of a solvent that can be used in the resin composition of the present embodiment, in addition to conventionally usable solvents such as chloroform, dichloromethane, and toluene, safer solvents such as N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), cyclohexanone, propylene glycol monomethyl ether acetate (PMA), diethylene glycol monoethyl ether acetate (CA), methyl ethyl ketone, and ethyl acetate can also be cited. The solvent can also be N,N-dimethylformamide (DMF). Only one solvent can be used, or two or more solvents can be used.

[0098] The amount of the solvent added to the resin composition of the present embodiment is not particularly limited and can be appropriately adjusted according to the application of the resin composition.

[0099] 2. Dry film

[0100] The dry film of this embodiment can be produced by coating the resin composition of this embodiment on a first film (e.g., a carrier film) and drying it to form a resin layer as a dry coating film. If necessary, a second film (e.g., a protective film) can be laminated on the resin layer. In other words, the dry film has a resin layer formed from the resin composition.

[0101] The first film is a film that supports the resin layer of the dry film. It is at least the portion that adheres to the resin layer when the dry film is laminated and integrally formed on a substrate such as a substrate by heating or other means. Examples of the first film include films made of thermoplastic resins such as polyester films such as polyethylene terephthalate or polyethylene naphthalate, polyimide films, polyamide-imide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, and polystyrene films, as well as surface-treated paper. Polyester films are preferred for their heat resistance, mechanical strength, and ease of use. The thickness of the first film is not particularly limited and can be appropriately selected within the range of approximately 10 to 150 μm depending on the intended use. The surface of the first film provided with the resin layer may also be subjected to a release treatment. Alternatively, the surface of the first film provided with the resin layer may be sprayed or coated with copper foil.

[0102] The second film is a film provided on the opposite side of the resin layer to the first film for the purpose of preventing dust and the like from adhering to the surface of the resin layer of the dry film and improving operability. When the second film is laminated and integrally formed by contacting the resin layer side of the dry film on a substrate such as a substrate by heating or the like, it is peeled off from the resin layer before lamination. As the second film, for example, films made of the thermoplastic resins exemplified for the first film above, and surface-treated paper, etc. can be used, among which polyester films, polyethylene films, and polypropylene films are preferred. The thickness of the second film is not particularly limited and can be appropriately selected within the range of approximately 10 to 150 μm depending on the intended use. The surface of the second film on which the resin layer is provided can also be subjected to a demolding treatment. In addition, it is preferred that the film has a smaller adhesive force between the resin layer and the second film than between the resin layer and the first film when the second film is peeled off.

[0103] As the film to which the resin composition of the present invention is applied when producing a dry film, either the first film or the second film can be used.

[0104] 3. Cured product

[0105] The cured product of the present embodiment is obtained using the resin composition of the present embodiment or the resin layer of the dry film of the present embodiment.

[0106] The method for curing is not particularly limited, and can be cured by a conventionally known method, for example, by heating at 150 to 230° C. for curing. The method for obtaining a cured product from a resin composition is not particularly limited, and can be appropriately changed according to the composition of the resin composition. As an example, after the process of applying the resin composition (for example, applying it using a coater, etc.) can be implemented on a circuit substrate having a circuit pattern, a drying process for drying the resin composition can be implemented as needed, and a heat curing process for thermally crosslinking the polyphenylene ether by heating (for example, heating using an inert gas furnace, a hot plate, a vacuum furnace, a vacuum press, etc.) can be implemented. In addition, the conditions for implementation in each process (such as coating thickness, drying temperature and time, heating temperature and time, etc.) can be appropriately changed according to the composition or purpose of the resin composition.

[0107] In addition, when a three-layer dry film with a resin layer sandwiched between a first film and a second film is used to obtain a cured product, a printed wiring board can be manufactured by the following method. The second film is peeled off from the dry film, and after heat lamination on a circuit substrate having a circuit pattern, a heat curing process for heat curing is implemented. The heat curing process can be cured in a furnace or cured by a hot plate press. When the substrate having a circuit and the dry film of the present invention are laminated or hot plate pressed, copper foil or a substrate having a circuit can also be laminated at the same time. At a position corresponding to a prescribed position on the substrate having a circuit pattern, a pattern or through hole is formed by laser irradiation or a drill bit to expose the circuit wiring, thereby enabling the manufacture of a printed wiring board. At this time, when there is a component (smear) that is not completely removed and remains on the circuit wiring in the pattern or through hole, a desmear treatment is performed. The first film can be peeled off at any one of the times after lamination, heat curing, laser processing or desmear treatment.

[0108] The heat curing step can be performed in an inert gas atmosphere such as nitrogen or in air. That is, the cured product of this embodiment can be obtained by curing the resin composition or resin layer of this embodiment in an inert gas atmosphere such as nitrogen or in air.

[0109] The glass transition temperature (Tg) of the obtained cured product is preferably 150° C. or higher, 160° C. or higher, 170° C. or higher, etc. When the glass transition temperature of the cured product is within the above range, the cured product has excellent mechanical properties, heat resistance, etc.

[0110] [Example]

[0111] Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0112] <(A) Synthesis of Resin (Branched PPE)>

[0113] 19.8 g (0.16 mol) of 2,6-dimethylphenol and 2.42 g (0.018 mol) of 2-allylphenol were added to a 500 mL separable flask, and the resulting mixture was dissolved in 261 g of toluene. The mixture was further adjusted to 0.18 wt% of di-μ-hydroxy-bis[(N,N,N',N'-tetramethylethylenediamine)copper(II)] chloride (Cu / TMEDA) and 0.16 wt% of tetramethylethylenediamine (TMEDA). Dry air was blown into the reaction solution at a flow rate of 75 mL / min while stirring at 200 rpm using four stirring blades. The mixture was reacted at 40°C for a predetermined time to obtain a reaction solution containing polyphenylene ether. After stopping the heating of the reaction solution and the blowing of dry air, di-μ-hydroxy-bis[(N,N,N',N'-tetramethylethylenediamine)copper(II)] chloride (Cu / TMEDA) was removed by filtration and reprecipitated with a mixture of 1200 mL of methanol, 4.0 mL of concentrated hydrochloric acid, and 7.0 mL of H2O2. The solution was removed by vacuum filtration, washed with methanol, and dried at 80°C for 24 hours to obtain a reactive branched polyphenylene ether. The resulting reactive branched polyphenylene ether (branched PPE) had a number average molecular weight (Mn) of 14,000 and a weight average molecular weight (Mw) of 38,000.

[0114] <(A) Measurement of Glass Transition Temperature (Tg) X of Resin (Branched PPE)>

[0115] (A) The glass transition temperature (Tg) of the resin (branched PPE) was measured under the following conditions using a differential scanning calorimetry (DSC) apparatus (Q100, heat flux type, manufactured by TA Instruments Japan Ltd.).

[0116] The temperature conditions were as follows: heating from 25°C to 300°C at a rate of 5°C / min (primary heating), rapid cooling from 300°C to -50°C using liquid nitrogen at a rate of 10°C / min, and then heating again from -50°C to 300°C at a rate of 5°C / min (secondary heating). The inflowing gas was nitrogen at a flow rate of 50 ml / min. The amount of sample used for measurement was 5 mg, and an aluminum container for measurement was used as the sample container.

[0117] The glass transition temperature (Tg) was measured from the DSC curve after the temperature was raised again. The glass transition temperature (Tg) was determined by finding the temperature (intermediate glass transition temperature) at the point where a straight line extending from each baseline and equidistant along the vertical axis intersected the curve of the step-like change in glass transition. The glass transition temperature (Tg) value of the resin (branched PPE) (A) is represented by X and is shown in Table 1 below.

[0118] <(B) Measurement of Exothermic Peak Top Temperature Y of Radical Polymerization Initiator>

[0119] The exothermic peak top temperatures of the compounds shown in Table 1 below used as the (B) radical polymerization initiator were measured using a differential scanning calorimetry (DSC) apparatus (Q100, heat flux type, manufactured by TA Instruments Japan Ltd.) under the following conditions.

[0120] The temperature conditions were: a temperature increase rate of 5°C / min from 25°C to 300°C. Nitrogen was introduced at a flow rate of 50 ml / min. The sample volume for measurement was 5 mg, and an aluminum container for measurement was used as the sample container.

[0121] In the obtained DSC curve, the value of the exothermic peak top temperature of the (B) radical polymerization initiator is Y, which is shown in Table 1 below.

[0122] Relationship between X and Y

[0123] Calculate whether the above X and Y satisfy the following formula.

[0124] (X-18)≤Y≤250

[0125] (Evaluation Criteria)

[0126] A: Satisfies the above formula

[0127] C: does not satisfy the above formula

[0128] <Preparation of Resin Composition>

[0129] (Example 1)

[0130] 9.7 g of anisole as a solvent was added to 1.60 g (100 parts by mass) of branched PPE and 1.20 g (75 parts by mass) of an elastomer (trade name "Tuftec H1051" manufactured by Asahi Kasei Corporation), and the mixture was thoroughly stirred with a rotary / orbital mixer to completely dissolve the mixture. To the resulting branched PPE resin solution, 1.20 g (75 parts by mass) of tricyclodecane dimethanol diacrylate (trade name "A-DCP" manufactured by Shin-Nakamura Chemical Co., Ltd.), a low molecular weight component, and 3.97 g (248 parts by mass) of a spherical silica filler (trade name "SC2050-HNF" manufactured by Yaduma Co., Ltd., solids concentration 70%) were added, and the mixture was stirred with a rotary / orbital mixer. Finally, 0.16 g (10 parts by mass) of ethyl ketone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetoxime) (manufactured by BASF Japan Ltd.: trade name "Irgacure OXE02") was added as a radical polymerization initiator, and the mixture was thoroughly stirred with a rotation / revolution mixer to obtain a varnish of the resin composition of Example 1.

[0131] (Examples 2-3, Comparative Examples 1-2)

[0132] Varnishes of the resin compositions of Examples 2 and 3 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the components and contents were set to the values ​​shown in Table 1 below.

[0133] <Preparation of Test Sample Substrates>

[0134] (CZ-treated substrate production process)

[0135] Both surfaces of a substrate (copper-clad laminate, manufactured by Mitsubishi Gas Chemical Co., Ltd., CCL-HL832NX, TYPE A series, thickness 0.4 mm) were roughened using a roughening agent (manufactured by MAG Corporation: trade name "CZ8100") at an etching amount of approximately 1 μm to produce a CZ-treated substrate.

[0136] (Dry film production process)

[0137] The varnish of the resin composition of each example and comparative example was applied to a high-smoothness grade PET film (manufactured by Toray Industries, Ltd.: trade name "R80") having a thickness of 38 μm as the first film, with an applicator, so that the thickness after drying was 35 μm. The film was then dried in a hot air circulation drying oven at 90°C for 15 minutes to obtain a dry film for the test of each example and comparative example.

[0138] (Lamination / Curing Process)

[0139] The test dry films of each example and comparative example were placed on both sides of the CZ-treated substrate obtained in the above manner so as to contact the resin layer of the dry film. Lamination was performed using a vacuum laminator ("CVP-600" manufactured by Nippon Mining Materials Co., Ltd.) at 140°C and 0.8 MPa. The laminates were then cured by heat treatment for 60 minutes in a hot air circulating dry drying oven at 200°C in an atmosphere to produce test substrates having cured products of the respective resin layers.

[0140] (Desmear process)

[0141] The surfaces of each test substrate were desmeared using a commercially available desmear treatment solution. Specifically, the test substrates, with the PET film peeled off, were immersed in a swelling solution (manufactured by Atotech Japan, trade name "Swelling DipSecuriganth P") at 60°C for 5 minutes, then immersed in a roughening solution (manufactured by Atotech Japan, trade name "Concentrate Compact CP") at 80°C for 20 minutes, and then immersed in a neutralizing solution (manufactured by Atotech Japan, trade name "ReductionSecuriganth P500") at 40°C for 5 minutes.

[0142] (Plating Layer Forming Step)

[0143] Electroless plating and electrolytic plating were performed on the surface of each test substrate after the desmear process to form a copper plating layer. Specifically, as the electroless plating treatment, the sample was immersed in a cleaning solution (manufactured by Uemura Industries: trade name “CLEANER MCD-PL”) at 40° C. for 5 minutes, immersed in a soft etching solution (manufactured by Uemura Industries: trade name “ALCUPMDP-2”) at 25° C. for 2 minutes, immersed in a catalyst imparting solution (manufactured by Uemura Industries: trade name “ALCUPMAT-SP”) at 40° C. for 5 minutes, immersed in a reducing solution (manufactured by Uemura Industries: trade name “ALCUP MRD-2-C / MAB-4-C / MAB-4-A”) at 35° C. for 3 minutes, immersed in a reaction treatment accelerating solution (manufactured by Uemura Industries: trade name “ALCUP MEL-3-A”) at 25° C. for 1 minute, and immersed in an electroless plating solution (manufactured by Uemura Industries: trade name “ALCUP PEA V2”) at 36° C. for 20 minutes to perform electroless copper plating. After that, as electrolytic plating treatment, the film was immersed in an acid cleaning solution (manufactured by Atotech Japan Co., Ltd.: trade name "Acid Cleaner FR") at 45°C for 5 minutes, immersed in a 10% sulfuric acid aqueous solution at 25°C for 1 minute, immersed in an electrolytic copper plating solution at 23°C for 60 minutes, and at a current density of 2 A / dm 2 Electrolytic copper plating was performed under the conditions of . Finally, as an annealing treatment, heat treatment was performed at 190° C. for 60 minutes in a hot air circulation dry drying furnace. The test sample substrate was obtained by the above production method.

[0144] <Evaluation of plating expansion>

[0145] The surfaces of the plated layers of the test sample substrates made with the resin compositions of the Examples and Comparative Examples were visually observed to evaluate plating expansion. The ratio of the plated layer expansion area on both sides of the substrate was calculated and evaluated using the following evaluation criteria.

[0146] (Evaluation Criteria)

[0147] A: The expansion area is less than 5%

[0148] C: The expansion area is more than 5%

[0149] <Stability evaluation under white light>

[0150] The varnish of the resin composition of each Example and Comparative Example was placed in a white plastic container ("High-Durability Container 'BHR-150' manufactured by Kinki Container Co., Ltd.) and allowed to stand for two days under a white light. The viscosity was measured before and after standing using a cone-plate viscometer (TVE-33H, manufactured by Toki Sangyo Co., Ltd.) and evaluated using the following evaluation criteria.

[0151] (Evaluation Criteria)

[0152] A: Viscosity increase rate is less than 30%

[0153] B: Viscosity increase rate is 30% or more and less than 100%

[0154] C: Viscosity increase rate is more than 100%

[0155]

Table 1

[0156]

[0157]

[0158] ※-Indicates no evaluation was conducted.

[0159] The details of each component in Table 1 are as follows. The amount of each component blended is parts by mass and is a value of solid content.

[0160] (A) Resin

[0161] *1: The above branched PPE

[0162] <(B) Radical Polymerization Initiator>

[0163] *2: "Irgacure OXE02" {Ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetoxime)} manufactured by BASF Japan Ltd.

[0164] *3: 2-(1-tert-Butylperoxy-1-methylethyl)-9H-thioxanthen-9-one manufactured by NOF Corporation

[0165] *4: "PERBUTYL P40" {α,α'-bis(tert-butylperoxy-m-isopropyl)benzene} manufactured by NOF Corporation

[0166] <(C) Low Molecular Weight Component>

[0167] *5: "A-DCP" tricyclodecane dimethanol diacrylate manufactured by Shin-Nakamura Chemical Co., Ltd.

[0168] *6: "TAIC" triallyl isocyanurate manufactured by Mitsubishi Chemical Corporation

[0169] <Elastomer>

[0170] *7: "Tuftec H1051" manufactured by Asahi Kasei Corporation

[0171] <Packing>

[0172] *8: SC2050-HNF silica slurry manufactured by Yaduma Co., Ltd., solid content 70% by mass, dispersion medium cyclohexanone

[0173] Industrial applicability

[0174] The resin composition, dry film, and cured product of the present invention can suppress expansion of the insulating layer even when cured in air atmosphere, and therefore can be used as an interlayer insulating material for printed wiring boards incorporated in electronic devices.

Claims

1. A resin composition, characterized in that comprising (A) a resin and (B) a radical polymerization initiator, The resin (A) has a free radical polymerizable functional group, When the glass transition temperature (Tg) of the resin (A) is set to X°C, and the temperature of the exothermic peak top of the radical polymerization initiator (B) when the temperature is increased from 25°C to 300°C at a rate of 5°C / min by differential scanning calorimetry (DSC) is set to Y°C, (X-18)≤Y≤250 is satisfied.

2. The resin composition according to claim 1, wherein The present invention contains (C) a low molecular weight component having a radical polymerizable functional group and a molecular weight of 1000 or less.

3. The resin composition according to claim 1, wherein The radical polymerizable functional group of the resin (A) is at least one selected from the group consisting of a vinyl group, an allyl group, and a maleimide group.

4. The resin composition according to claim 1, wherein The (B) radical polymerization initiator includes a peroxide structure (excluding a structure represented by -OOH) or an oxime ester structure.

5. The resin composition according to claim 1, wherein The resin (A) is a branched polyphenylene ether resin.

6. The resin composition according to claim 1, wherein The weight average molecular weight Mw of the resin (A) is 2000 or more.

7. A dry film, characterized in that A resin layer formed from the resin composition according to claim 1 is provided.

8. A cured product, characterized in that: A cured product obtained by using the resin composition according to claim 1 or the resin layer of the dry film according to claim 7.

9. The cured product according to claim 8, wherein The resin composition or the resin layer is obtained by curing the resin composition or the resin layer in an air atmosphere.

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