Resin composition, dry film, and cured product

Abstract

To provide a resin composition capable of suppressing swelling of an insulating layer even when cured in an air atmosphere; a dry film including a resin layer formed of 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 and (B) a radical polymerization initiator, the resin (A) has a radically polymerizable functional group, and when a glass transition temperature (Tg) of the resin (A) is X°C, and the temperature of an exothermic peak top when the radical polymerization initiator (B) is heated from 25°C to 300°C at 5°C / min by differential scanning calorimetry (DSC) is Y°C, (X-18)≤Y≤250 is satisfied.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In recent years, with the spread of high-capacity, high-speed communications such as fifth-generation communication systems (5G) and millimeter-wave radar for automotive ADAS (Advanced Driver Assistance Systems), signals from electronic devices are becoming increasingly high-frequency.

[0003] Printed wiring boards built into such electronic devices have traditionally used curable resin compositions primarily composed of epoxy resins as interlayer insulating materials. Cured products made from such compositions have high dielectric constants (Dk) and dielectric loss tangents (Df), resulting in increased transmission loss for high-frequency signals, signal attenuation, heat generation, and other problems. For this reason, polyphenylene ethers, which offer excellent low dielectric properties, have attracted attention.

[0004] Non-Patent Document 1 proposes polyphenylene ether with improved heat resistance, which is made into a thermosetting resin by introducing an allyl group into the molecule of polyphenylene ether. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] J.Nunoshige, H.Akahoshi, Y.Shibasaki, M.Ueda, J.Polym.Sci.Part.A:Polym.Chem.2008,46,5278-5282. Summary of the Invention [Problem to be solved by the invention]

[0006] When a resin composition using such polyphenylene ether is cured by a radical reaction and used as an interlayer insulating material, it is common to perform the curing in an inert gas atmosphere such as nitrogen so that the curing reaction is not inhibited by oxygen.

[0007] On the other hand, from the viewpoint of equipment and safety, it is desirable to obtain a cured product by curing in an air atmosphere instead of an inert gas such as nitrogen. However, when a resin composition using polyphenylene ether is cured in an air atmosphere, the curing reaction does not proceed smoothly, and plating blister (blister) occurs between the substrate and the insulating (cured) layer. Plating blister refers to a phenomenon in which part of the insulating layer becomes detached from the substrate during the plating process. For this reason, when curing is performed in an air atmosphere, it has been difficult to obtain a cured product of the same quality as when curing is performed in an inert gas atmosphere.

[0008] Therefore, the problem that the present invention aims to solve is to provide a resin composition that can suppress swelling of the insulating layer even when cured in an atmospheric environment; 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. [Means for solving the problem]

[0009] One aspect of the present invention is a resin composition comprising (A) resin and (B) radical polymerization initiator, wherein the (A) resin has a radically polymerizable functional group, and where X°C is the glass transition temperature (Tg) of the (A) resin and Y°C is the temperature at the top of the exothermic peak when the (B) radical polymerization initiator is heated from 25°C to 300°C at a rate of 5°C / min as measured by differential scanning calorimetry (DSC), the resin composition satisfies (X-18)≦Y≦250.

[0010] 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 1,000 or less.

[0011] In the resin composition of the above aspect, the radically polymerizable functional group of the resin (A) is preferably one or more selected from the group consisting of a vinyl group, an allyl group, and a maleimide group.

[0012] In the resin composition of the above aspect, the radical polymerization initiator (B) preferably contains a peroxide structure (excluding a structure represented by —OOH) or an oxime ester structure.

[0013] In the resin composition of the above aspect, the (A) resin is preferably a branched polyphenylene ether resin.

[0014] In the resin composition of the above embodiment, the weight average molecular weight Mw of the (A) resin is preferably 2,000 or more.

[0015] Another aspect of the present invention is a dry film, which includes a resin layer formed from the resin composition of the above aspect.

[0016] Another aspect of the present invention is a cured product obtained using the resin composition of the above aspect or the resin layer of the dry film of the above aspect.

[0017] The cured product of the above embodiment is preferably obtained by curing the resin composition or the resin layer in an air atmosphere. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a resin composition that can suppress swelling of an insulating layer even when cured under atmospheric conditions; 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 OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail. In this specification, the expression "a to b" in the description of a range of numerical values ​​means that the range is from a to b, unless otherwise specified.

[0020] When the compounds described have isomers, all possible isomers can be used in the present invention unless otherwise specified.

[0021] In this specification, phenols that are used as raw materials for polyphenylene ether (PPE) and can become structural units of polyphenylene ether are collectively referred to as "raw material phenols."

[0022] In this specification, when describing raw material phenols, expressions such as "ortho position" and "para position" refer to the position of the phenolic hydroxyl group as the reference (ipso position) unless otherwise specified.

[0023] In this specification, when simply expressed as "ortho position" or the like, it means "at least one of the ortho positions", etc. Therefore, unless a particular contradiction occurs, when simply expressed as "ortho position", it may be interpreted as indicating either one of the ortho positions or as indicating both ortho positions.

[0024] In this specification, polyphenylene ether in which some or all of the functional groups (e.g., hydroxyl groups) of polyphenylene ether have been modified may be simply referred to as “polyphenylene ether.” Therefore, when “polyphenylene ether” is used, it includes both unmodified polyphenylene ether and modified polyphenylene ether, unless otherwise inconsistent.

[0025] In this specification, monohydric phenols are mainly disclosed as the raw material phenols, but polyhydric phenols may also be used as the raw material phenols within the range that does not impair the effects of the present invention.

[0026] In this specification, when the upper and lower limits of a numerical range are separately stated, all combinations of each lower limit and each upper limit are considered to be substantially stated within a consistent range.

[0027] In this specification, the term "solid content" is used to mean non-volatile content (components other than volatile components such as solvents).

[0028] In this specification, "resin" refers to a compound having a molecular weight distribution, with the molecular weight distribution (Mw / Mn) exceeding 1. Mw represents the weight-average molecular weight, and Mn represents the number-average molecular weight. Furthermore, "low-molecular-weight component" refers to a compound consisting of a single molecule without a molecular weight distribution.

[0029] In this specification, there may be cases where the components contained in the resin composition and the components contained in the resin layer, which is a dried coating film of the resin composition, are described without distinction.

[0030] 1.Resin composition The resin composition of the present embodiment contains (A) a resin, (B) a radical polymerization initiator, and (C) a low-molecular-weight component. The resin composition may also contain other components as long as the effects of the present invention are not impaired.

[0031] The resin composition of this embodiment satisfies (X-18)≦Y≦250, where X°C is the glass transition temperature (Tg) of the (A) resin described below, and Y°C is the exothermic peak top temperature when the (B) radical polymerization initiator described below is heated from 25°C to 300°C at a rate of 5°C / min by differential scanning calorimetry (DSC). Each component contained in the resin composition will be described in detail below.

[0032] 1-1.(A) Resin The resin (A) is not particularly limited as long as it is a resin (polymer) that has a radically polymerizable functional group and undergoes a polymerization reaction in the presence of a radical polymerization initiator.

[0033] The radical polymerizable functional group is preferably, for example, 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 (such as a vinyl group, an allyl group, or a propenyl group), and a maleimide group. Among the above-mentioned ethylenically unsaturated groups, from the viewpoint of dielectric properties, the 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. The (A) resin may have one or more types of radical polymerizable functional groups.

[0034] The number of radically polymerizable functional groups that the resin (A) has in its molecule is not particularly limited as long as it is one or more, and from the viewpoint of mechanical properties, it is preferably two or more.

[0035] The resin (A) is not particularly limited, and examples thereof include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyamide resins; polyamideimide resins; polyphenylene sulfide resins; polyether ether ketone resins; polyether sulfone 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 can be used alone or in combination of two or more.

[0036] From the viewpoint of adjusting the glass transition temperature (Tg) to an appropriate value, 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.

[0037] A polyphenylene ether resin having a branched structure (also referred to as a branched polyphenylene ether resin or branched PPE) has excellent solubility in solvents and excellent compatibility and reactivity with each component in the resin composition, and therefore, the (A) resin is preferably a branched polyphenylene ether resin.

[0038] The branched polyphenylene ether resin is a polyphenylene ether produced from raw material phenols containing phenols having hydrogen atoms at the ortho and para positions. Since such phenols have hydrogen atoms at the ortho positions, ether bonds can be formed not only at the ipso and para positions but also at the ortho positions when oxidatively polymerized with the phenols. Therefore, the polyphenylene ether obtained by using such phenols as raw material phenols can form a branched chain structure.

[0039] The glass transition temperature (Tg) of the (A) resin is preferably 100°C or higher, 150°C or higher, or 180°C or higher, and is preferably 230°C or lower, 220°C or lower, or 200°C or lower. The glass transition temperature (Tg) can be measured by differential scanning calorimetry (DSC). When the glass transition temperature of the (A) resin is within the above range, a cured product having excellent mechanical properties, heat resistance, etc. can be obtained.

[0040] The weight-average molecular weight (Mw) of the (A) resin is preferably 1,000 or more, 1,500 or more, or 2,000 or more, and is preferably 150,000 or less, 100,000 or less, or 80,000 or less. The weight-average molecular weight (Mw) can be determined from the standard polystyrene equivalent value by gel permeation chromatography (GPC). Measurements can be performed using a high-speed GPC instrument (HLC-8320GPC, manufactured by Tosoh Corporation) as the measuring device, chloroform as the eluent, and an RI detector as the detector.

[0041] The (A) resin may be a mixture of two or more types of polyphenylene ethers each having different types of raw material phenols.

[0042] The amount of (A) resin added is, based on the total solid content of the resin composition, preferably 0.1 mass% or more, 0.5 mass% or more, 1 mass% or more, 3 mass% or more, 5 mass% or more, and preferably 40 mass% or less, 35 mass% or less, 30 mass% or less, 25 mass% or less, for example.

[0043] 1-2.(B) Radical polymerization initiator The (B) radical polymerization initiator is a compound that has the ability to generate radicals when irradiated with heat or light such as ultraviolet light. Depending on the application of the resin composition, the (B) radical polymerization initiator may be any of a thermal polymerization initiator (thermal radical initiator) that generates radicals when irradiated with heat, a photopolymerization initiator (photoradical initiator) that generates radicals when irradiated with light, or a photothermal dual initiator that generates radicals when irradiated with both light and heat.

[0044] The radical polymerization initiator will be described in detail below. Note that the thermal polymerization initiator and the photothermal dual initiator, and the photopolymerization initiator and the photothermal dual initiator may be mentioned in some cases.

[0045] <Thermal polymerization initiator> The thermal polymerization initiator is preferably a peroxide containing a peroxide structure (-OO-). Examples of the peroxide include methyl ethyl ketone peroxide, methyl acetoacetate peroxide, acetylacetonperoxide, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)butane, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, and 2,5- Examples of peroxyl groups include dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-butene, acetyl peroxide, octanoyl peroxide, lauroyl peroxide, benzoyl peroxide, m-toluyl peroxide, diisopropyl peroxydicarbonate, t-butylene peroxybenzoate, di-t-butyl peroxide, t-butylperoxyisopropyl monocarbonate, and α,α'-bis(t-butylperoxy-m-isopropyl)benzene.

[0046] Among these, from the viewpoints of ease of handling and reactivity, peroxides having a one-minute half-life temperature of 130° C. to 180° C. are desirable. Such peroxides have a relatively high reaction initiation temperature, and therefore do not readily promote curing when curing is not required, such as during drying, and do not impair the storage stability of the polyphenylene ether resin composition. In addition, due to their low volatility, they do not volatilize during drying or storage, resulting in good stability.

[0047] Furthermore, as the thermal polymerization initiator, an azo compound such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), or 2,2'-azobis(4-methoxy-2'-dimethylvaleronitrile) may be used.

[0048] These can be used alone or in combination.

[0049] <Photopolymerization initiator> 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 benzoic acid ester structure, a titanocene structure, etc. Among these, those having an oxime ester structure are preferred.

[0050] Examples of compounds 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 ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (OXE02).

[0051] These can be used alone or in combination.

[0052] <Photothermal dual initiator> As the photothermal dual initiator, a peroxide containing a peroxide structure (—OO—) is preferred, such as 3,3,4,4-tetra(t-butylperoxycarbonyl)benzophenone, 2-(1-t-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one, and the like.

[0053] Among the above, the radical polymerization initiator (B) preferably contains a peroxide structure (excluding a structure represented by -OOH) or an oxime ester structure. Furthermore, the radical polymerization initiator (B) is preferably a compound having higher solvent solubility among the above, and more preferably, for example, a compound having a structure containing a heteroatom.

[0054] More specifically, 2-(1-t-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one, such as commercially available product Irgacure OXE02 (manufactured by BASF Japan Ltd.), is more preferred, and 2-(1-t-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one is particularly preferred. By using 2-(1-t-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one as the (B) radical polymerization initiator, the stability of the resin composition can be ensured even under white light.

[0055] When the temperature of the (B) radical polymerization initiator is increased from 25°C to 300°C at a rate of 5°C / min by differential scanning calorimetry (DSC), the exothermic peak top temperature Y°C satisfies (X-18)≦Y≦250, where X°C is the glass transition temperature (Tg) of the (A) resin. That is, Y is preferably 82°C or higher, 132°C or higher, 162°C or higher, or the like, and can be a value of 250°C or lower.

[0056] When Y is within the above range, the stability of the radical polymerization initiator (B) can be maintained up to a temperature relatively close to the glass transition temperature (Tg) X of the resin (A), thereby improving the crosslink density and breaking strength when the resin composition is cured. Furthermore, plating blister can be suppressed even when the resin composition is cured in the air.

[0057] The amount of the radical polymerization initiator (B) added can be 0.01 to 15 parts by mass per 100 parts by mass of the solid content of the resin (A).

[0058] 1-3.(C) Low molecular weight component The (C) low-molecular-weight component of this embodiment has a radically polymerizable functional group and a molecular weight of not more than 1,000. The radically polymerizable functional group is the same as the radically polymerizable functional group described above in "1-1. (A) Resin," and therefore a description thereof will be omitted here.

[0059] The (C) low-molecular-weight component is a compound that undergoes a curing reaction with the (A) resin, and is preferably one that is compatible with the (A) resin. Examples include polyfunctional vinyl compounds such as divinylbenzene, divinylnaphthalene, and divinylbiphenyl; vinylbenzyl ether compounds synthesized by the reaction of phenol with vinylbenzyl chloride; allyl ether compounds synthesized by the reaction of styrene monomer, phenol with allyl chloride; (meth)acrylate compounds (methacrylate compounds and acrylate compounds); and trialkenyl isocyanurate.

[0060] Among these, trialkenyl isocyanurates are preferred, as they have particularly good compatibility with the (A) resin and can lower the dielectric properties and improve the heat resistance of the cured product, and specifically triallyl isocyanurate (hereinafter referred to as TAIC (registered trademark)) and triallyl cyanurate (hereinafter referred to as TAC) are preferred. The (C) low-molecular-weight component can be used alone or in combination of two or more.

[0061] From the viewpoint of crosslink density, the molecular weight of the (C) low-molecular-weight component is preferably 1,000 or less, more preferably 500 or less, and even more preferably 400 or less. From the viewpoint of the mechanical properties of the resulting cured product, the number of functional groups of the (C) low-molecular-weight component is preferably 2 to 4. From the viewpoint of melt viscosity, the melting point of the (C) low-molecular-weight component is preferably 80°C or less. By including the above-mentioned (C) low-molecular-weight component, warping of the dry film described below can be reduced when the resin composition is produced from the dry film. Furthermore, plating blister can be suppressed even when the resin composition is cured in the air.

[0062] The amount of the (C) low molecular weight component added can be 10 to 200 parts by mass, 50 to 150 parts by mass, etc., per 100 parts by mass of the solid content of the (A) resin.

[0063] 1-4.Other ingredients Other components may include known components such as fillers (inorganic fillers and organic fillers such as PTFE powder), flame retardancy improvers (phosphorus-based compounds, etc.), cellulose nanofibers, cyanate ester resins, epoxy resins, phenol novolac resins, elastomers, dispersants, curing accelerators, crosslinking curing agents (crosslinking agents), adhesion promoters, and solvents.

[0064] <Inorganic filler> Examples of inorganic fillers that can be used include metal oxides such as alumina and titanium oxide; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; clay minerals such as talc and mica; fillers having a ferovskite-type crystal structure such as barium titanate and strontium titanate; silica, boron nitride, aluminum borate, barium sulfate, and calcium carbonate.

[0065] Among the inorganic fillers mentioned above, silica can improve the film-forming properties of the resin composition and can achieve a high level of low dielectric loss tangent and low thermal expansion.

[0066] The average particle size of the silica is preferably 0.02 to 10 μm, more preferably 0.02 to 3 μm. Here, the average particle size can be determined as the median diameter (d50, volume basis) based on cumulative distribution from particle size distribution measured by a laser diffraction / scattering method using a commercially available laser diffraction / scattering particle size distribution analyzer. The average particle size of the silica refers to the value measured as described above on a powder prior to preparation (pre-mixing and kneading) of the resin composition.

[0067] It is also possible to use silica with different average particle sizes in combination. From the viewpoint of achieving a high silica loading, for example, silica with an average particle size of 1 μm or more may be used in combination with fine silica with an average particle size of less than 1 μm, on the order of nanometers.

[0068] The silica may be surface-treated with a coupling agent. Treating the surface with a silane coupling agent can improve dispersibility with polyphenylene ether and affinity with organic solvents.

[0069] Examples of silane coupling agents that can be used include epoxy silane coupling agents, mercapto silane coupling agents, and vinyl silane coupling agents. Examples of epoxy silane coupling agents that can be used include γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldimethoxysilane. Examples of mercapto silane coupling agents that can be used include γ-mercaptopropyltriethoxysilane. Examples of vinyl silane coupling agents that can be used include vinyltriethoxysilane.

[0070] The amount of the silane coupling agent used may be, for example, 0.1 to 5 parts by mass, or 0.5 to 3 parts by mass, per 100 parts by mass of silica.

[0071] The amount of filler such as silica added may be 50 to 400 parts by mass or 100 to 400 parts by mass per 100 parts by mass of the solid content of the (A) resin. Alternatively, the amount of filler such as silica added may be 30 to 80% by mass based on the total solid content of the resin composition. By setting the amount of filler added within the above range, warping of the dry film described below can be reduced when the resin composition is produced from the dry film. Furthermore, plating blister can be suppressed even when the resin composition is cured in the air.

[0072] <Elastomer> The inclusion of an elastomer can improve the toughness of the dry film and cured product described below. Examples of the elastomer include diene-based synthetic rubbers such as polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, polychloroprene rubber, nitrile rubber, and ethylene-propylene rubber; non-diene-based synthetic rubbers such as ethylene-propylene rubber, butyl rubber, acrylic rubber, polyurethane rubber, fluororubber, silicone rubber, and epichlorohydrin rubber; natural rubber, styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic elastomers, and silicone-based elastomers.

[0073] From the viewpoints of compatibility with the (A) resin and dielectric properties, at least a portion of the elastomer is preferably a styrene-based elastomer. Examples of styrene-based elastomers include styrene-butadiene copolymers such as styrene-butadiene-styrene block copolymer and styrene-butadiene-butylene-styrene block copolymer; styrene-isoprene copolymers such as styrene-isoprene-styrene block copolymer; styrene-ethylene-butylene-styrene block copolymer and styrene-ethylene-propylene-styrene block copolymer. Styrene-based elastomers without unsaturated carbon bonds, such as styrene-ethylene-butylene-styrene block copolymer, are preferred because they provide particularly good dielectric properties to the resulting cured product.

[0074] 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 It can be determined from the integral ratio of the spectrum measured by H-NMR.

[0075] Here, raw material monomers for styrene elastomers include not only styrene but also styrene derivatives such as α-methylstyrene, 3-methylstyrene, 4-propylstyrene, and 4-cyclohexylstyrene.

[0076] The content of the styrene-based elastomer in 100% by weight of the elastomer may be, for example, 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 100% by weight.

[0077] The elastomer may be modified with (meth)acrylic acid, maleic acid, anhydrides or esters thereof, or may be obtained by adding water to the remaining unsaturated bonds of a diene-based elastomer.

[0078] The number average molecular weight of the elastomer may be 1,000 to 150,000. When the number average molecular weight is equal to or greater than the lower limit, low thermal expansion is excellent, and when it is equal to or less than the upper limit, compatibility with other components is excellent.

[0079] The amount of elastomer added in the resin composition may be 10 to 300 parts by mass per 100 parts by mass of the solid content of the (A) resin. Alternatively, the amount of elastomer added may be 3 to 65% by mass based on the total amount of solid content in the resin composition. When the amount is within the above range, a good balance of good tensile properties, adhesion, and heat resistance can be achieved.

[0080] <Solvent> The resin composition of the present invention is usually provided or used in a state in which the (A) resin is dissolved in a solvent (dissolving agent).

[0081] Examples of solvents that can be used in the resin composition of this embodiment include conventionally usable solvents such as chloroform, methylene chloride, and toluene, as well as relatively safe 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. The solvent may be N,N-dimethylformamide (DMF). Only one solvent may be used, or two or more solvents may be used.

[0082] The amount of solvent added to the resin composition of this embodiment is not particularly limited, and can be adjusted appropriately depending on the application of the resin composition.

[0083] 2. Dry film The dry film of this embodiment can be produced by applying the resin composition of this embodiment to a first film (e.g., a carrier film) and drying it to form a resin layer as a dry coating. If necessary, a second film (e.g., a protective film) can be laminated on the resin layer. That is, the dry film has a resin layer formed from the resin composition.

[0084] The first film serves to support the resin layer of the dry film and adheres to at least the resin layer when the dry film is integrally molded by laminating the resin layer side of the dry film onto a substrate or other base material by heating or the like. Examples of the first film include polyester films such as polyethylene terephthalate and polyethylene naphthalate, thermoplastic resin films such as polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, and polystyrene films, and surface-treated paper. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, and ease of handling. The thickness of the first film is not particularly limited and can be appropriately selected depending on the application within the range of approximately 10 to 150 μm. The surface of the first film on which the resin layer is to be formed may be subjected to a release treatment. Furthermore, sputtering or copper foil may be formed on the surface of the first film on which the resin layer is to be formed.

[0085] The second film is provided on the opposite side of the resin layer from the first film for the purposes of preventing dust and other particles from adhering to the surface of the resin layer of the dry film and improving handleability. The second film is peeled off from the resin layer before lamination when the dry film is integrally molded by laminating the resin layer side of the dry film onto a substrate or other base material by heating or other means so that the resin layer side is in contact with the base material. Examples of the second film that can be used include films made of thermoplastic resins such as those exemplified for the first film, and surface-treated paper. Among these, polyester film, polyethylene film, and polypropylene film are preferred. The thickness of the second film is not particularly limited and can be appropriately selected depending on the application within the range of approximately 10 to 150 μm. The surface of the second film on which the resin layer is to be provided may be subjected to a release treatment. Furthermore, it is preferable that the adhesive strength between the resin layer and the second film is weaker than the adhesive strength between the resin layer and the first film when the second film is peeled off.

[0086] When producing a dry film, the film to which the resin composition of the present invention is applied may be either the first film or the second film.

[0087] 3.Cured product The cured product of this embodiment can be obtained by curing the resin composition of this embodiment or the resin layer of the dry film of this embodiment.

[0088] The curing method is not particularly limited, and may be a conventionally known method, such as by heating at 150 to 230°C. The method for obtaining a cured product from the resin composition is also not particularly limited, and may be appropriately modified depending on the composition of the resin composition. For example, after a step of applying the resin composition to a circuit substrate on which a circuit pattern has been formed (e.g., by application with an applicator, etc.), a drying step of drying the resin composition may be performed as needed, and a thermal curing step of thermally crosslinking the polyphenylene ether by heating (e.g., by heating with an inert gas oven, hot plate, vacuum oven, vacuum press, etc.) may be performed. The conditions for each step (e.g., coating thickness, drying temperature and time, heating temperature and time, etc.) may be appropriately modified depending on the composition and application of the resin composition.

[0089] Furthermore, when a cured product is obtained using a three-layer dry film in which a resin layer is sandwiched between a first film and a second film, a printed wiring board can be manufactured by the following method. The second film is peeled from the dry film, and the resulting film is heat-laminated onto a circuit board on which a circuit pattern has been formed, followed by a thermal curing step. The thermal curing step may involve curing in an oven or by hot plate pressing. When laminating or hot plate pressing the dry film of the present invention to a substrate on which a circuit has been formed, copper foil or a substrate on which a circuit has been formed can also be laminated simultaneously. A printed wiring board can be manufactured by forming a pattern or via hole by laser irradiation or drilling at a position corresponding to a predetermined position on the substrate on which the circuit pattern has been formed, thereby exposing the circuit wiring. At this time, if any remaining components (smears) remain on the circuit wiring in the pattern or via hole and are not completely removed, a desmear treatment is performed. The first film may be peeled off either after lamination, thermal curing, laser processing, or desmear treatment.

[0090] The above-described thermal curing step may be carried out in an inert gas atmosphere such as nitrogen, or in the air. That is, the cured product of the present embodiment can be obtained by curing the resin composition or resin layer of the present embodiment in the air, as well as in an inert gas atmosphere such as nitrogen.

[0091] 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 will have excellent mechanical properties, heat resistance, etc. [Example]

[0092] EXAMPLES Next, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these in any way.

[0093] <(A) Synthesis of Resin (Branched PPE)> A 500 mL separable flask was charged with 19.8 g (0.16 mol) of 2,6-dimethylphenol and 2.42 g (0.018 mol) of 2-allylphenol, and the resulting mixture was dissolved in 261 g of toluene. The resulting mixture was further adjusted to 0.18 wt% di-μ-hydroxo-bis[(N,N,N'-tetramethylethylenediamine)copper(II)] chloride (Cu / TMEDA) and 0.16 wt% tetramethylethylenediamine (TMEDA). Dry air was blown into the reaction mixture at a flow rate of 75 mL / min. The mixture was stirred at 200 rpm with a four-blade paddle at 40°C for a predetermined time, yielding a reaction mixture containing polyphenylene ether. After heating the reaction solution and stopping the blowing of dry air, di-μ-hydroxo-bis[(N,N,N',N'-tetramethylethylenediamine)copper(II)] chloride (Cu / TMEDA) was removed by filtration and reprecipitated in a mixture of 1,200 mL of methanol, 4.0 mL of concentrated hydrochloric acid, and 7.0 mL of HO. The precipitate was filtered off, washed with methanol, and dried at 80°C for 24 hours to obtain 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.

[0094] <(A) Measurement of the glass transition temperature (Tg)X of resin (branched PPE)> (A) The glass transition temperature (Tg) of the resin (branched PPE) was measured using a differential scanning calorimetry (DSC) device (TA Instruments Japan Q100, heat flux type) under the following conditions.

[0095] The temperature conditions were as follows: the temperature was raised from 25°C to 300°C at a rate of 5°C / min (1st run), then rapidly cooled from 300°C to -50°C at 10°C / min using liquid nitrogen, and then again raised from -50°C to 300°C at a rate of 5°C / min (2nd run). The inflow gas was nitrogen, and the flow rate of nitrogen gas was 50 mL / min. The amount of sample for measurement was 5 mg, and an aluminum container for measurement was used as the sample container.

[0096] The glass transition temperature (Tg) was measured from the DSC curve of the second run. The glass transition temperature (Tg) was determined as the temperature at the point where a line equidistant in the vertical direction from the extended line of each baseline intersects with the curve of the stepwise change in the glass transition (mid-glass transition temperature). The glass transition temperature (Tg) of (A) Resin (branched PPE) is shown in Table 1 below, with X representing the value.

[0097] <(B) Measurement of the exothermic peak top temperature Y of the radical polymerization initiator> (B) The top temperatures of the exothermic peaks of the compounds shown in Table 1 below used as radical polymerization initiators were measured using a differential scanning calorimeter (DSC) (TA Instruments Japan Q100, heat flux type) under the following conditions:

[0098] The temperature was raised from 25°C to 300°C at a rate of 5°C / min. The inflow gas was nitrogen, and the flow rate of the nitrogen gas was 50 mL / min. The amount of sample for measurement was 5 mg, and an aluminum container for measurement was used as the sample container.

[0099] In the obtained DSC curve, the value of the exothermic peak top temperature of the (B) radical polymerization initiator was designated as Y and shown in Table 1 below.

[0100] <Relationship between X and Y> It was calculated whether the above-mentioned X and Y satisfy the following formula. (X - 18) ≤ Y ≤ 250 (Evaluation criteria) A: Satisfies the above formula C: Does not satisfy the above formula

[0101] <Preparation of resin composition> (Example 1) To 1.60 g (100 parts by mass) of branched PPE and 1.20 g (75 parts by mass) of an elastomer (manufactured by Asahi Kasei Corporation: trade name "Tuftec H1051"), 9.7 g of anisole as a solvent was added and thoroughly stirred with a rotary-revolution mixer to completely dissolve it. To the branched PPE resin solution thus obtained, 1.20 g (75 parts by mass) of tricyclodecane dimethanol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.: trade name "A-DCP"), which is a low molecular weight component, and 3.97 g (248 parts by mass) of spherical silica filler (manufactured by Admatechs Co., Ltd.: trade name "SC2050-HNF", solid content concentration 70%) were added respectively and stirred with a rotary-revolution mixer. Finally, 0.16 g (10 parts by mass) of ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetoxime) (manufactured by BASF Japan Ltd.: trade name "Irgacure OXE02"), which is a radical polymerization initiator, was added and thoroughly stirred with a rotary-revolution mixer to obtain a varnish of the resin composition of Example 1.

[0102] (Examples 2 to 3, Comparative Examples 1 to 2) Resin composition varnishes according to Examples 2 to 3 and Comparative Examples 1 to 2 were obtained in the same manner as in Example 1, except that the amounts of each component were the values shown in Table 1 below.

[0103] <Production of test sample substrate> (Production process of CZ-treated substrate) A CZ-treated substrate was produced by roughening both surfaces of a substrate (copper-clad laminate, manufactured by Mitsubishi Gas Chemical Company, Inc., CCL-HL832NX, TYPE A Series, thickness 0.4 mm) using a roughening agent (manufactured by MEC Co., Ltd., product name "CZ8100") under conditions such that the etching depth was approximately 1 μm.

[0104] (Dry film manufacturing process) The varnish of the resin composition of each Example and Comparative Example was applied with an applicator onto a first film, a 38 μm thick, high-smooth grade PET film (manufactured by Toray Industries, Inc.: product name "R80"), so that the thickness after drying would be 35 μm, and then dried at 90°C for 15 minutes in a hot air circulation drying oven to obtain a test dry film of each Example and Comparative Example.

[0105] (Lamination / curing process) The test dry films of each example and comparative example were placed on both sides of the CZ-treated substrate obtained by the above procedure, with the resin layers of the dry films in contact with each other. After lamination at 140°C and 0.8 MPa using a vacuum laminator (Nikko Materials Co., Ltd., CVP-600), the films were cured by heating in a hot air circulating dry oven at 200°C for 60 minutes in an air atmosphere to produce test substrates with cured resin layers.

[0106] (Desmear process) The surface of each test substrate was desmeared using a commercially available desmearing solution. Specifically, the test substrate from which the PET film had been peeled was immersed in a swelling solution (manufactured by Atotech Japan, Inc., product name "Swelling Dip Securigant P") at 60°C for 5 minutes, then in a roughening solution (manufactured by Atotech Japan, Inc., product name "Concentrate Compact CP") at 80°C for 20 minutes, and then in a neutralizing solution (manufactured by Atotech Japan, Inc., product name "Reduction Securigant P500") at 40°C for 5 minutes.

[0107] (Plating layer formation process) The surface of each test substrate that had undergone the desmearing process was subjected to electroless plating and electrolytic plating to form a copper plating layer. Specifically, the electroless plating was performed by immersing the substrate in a cleaner treatment solution (manufactured by Uemura Kogyo Co., Ltd., product name "Cleaner MCD-PL") at 40°C for 5 minutes, in a soft etching treatment solution (manufactured by Uemura Kogyo Co., Ltd., product name "Alucup MDP-2") at 25°C for 2 minutes, in a catalyst application treatment solution (manufactured by Uemura Kogyo Co., Ltd., product name "Alucup MAT-SP") at 40°C for 5 minutes, in a reduction treatment solution (manufactured by Uemura Kogyo Co., Ltd., product name "Alucup MRD-2-C / MAB-4-C / MAB-4-A") at 35°C for 3 minutes, in a reaction treatment acceleration treatment solution (manufactured by Uemura Kogyo Co., Ltd., product name "Alucup MEL-3-A") at 25°C for 1 minute, and in an electroless plating treatment solution (manufactured by Uemura Kogyo Co., Ltd., product name "Sulcup PEA") at 25°C for 1 minute. The specimen was then immersed in an acid cleaning solution (manufactured by Atotech Japan, trade name "Acid Cleaner FR") at 45°C for 20 minutes, then in a 10% aqueous sulfuric acid solution at 25°C for 1 minute, and finally in an electrolytic copper plating solution at 23°C for 60 minutes, with a current density of 2 A / dm 2 Finally, as an annealing treatment, a heat treatment was carried out at 190°C for 60 minutes in a hot air circulation dry oven. A test sample substrate was obtained by the above-mentioned manufacturing method.

[0108] <Evaluation of plating blister> The surfaces of the test sample substrates made with the resin compositions of each Example and Comparative Example after plating layer formation were visually inspected to evaluate plating blistering. The percentage of the area where blistering occurred in the plating layer on both sides of the substrate was calculated and evaluated according to the following evaluation criteria. (Evaluation criteria) A: The percentage of the area where swelling occurred is less than 5% C: The percentage of the area where swelling occurred is 5% or more

[0109] <Evaluation of stability under white light> The varnish of the resin composition of each example and comparative example was placed in a white plastic container (Hi-Resist "BHR-150" manufactured by Kinki Container Co., Ltd.) and left to stand under white light for 2 days. The viscosity was measured before and after standing using a cone-plate viscometer (TVE-33H, manufactured by Toki Sangyo Co., Ltd.) and evaluated according to the following evaluation criteria. (Evaluation criteria) A: Viscosity increase rate is less than 30% B: Viscosity increase rate is 30% or more but less than 100% C: Viscosity increase rate is 100% or more

[0110] [Table 1] *- indicates that the item has not been evaluated.

[0111] Details of each component in Table 1 are shown below. The blend amount of each component is in parts by mass and is the value in terms of solid content. <(A) Resin> *1: The branched PPE mentioned above <(B) Radical Polymerization Initiator> *2: "Irgacure OXE02" manufactured by BASF Japan Ltd. {ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime)} *3: NOF Corporation "2-(1-t-butylperoxy-1-methylethyl)-9H-thioxanthen-9-one" *4: "Perbutyl P40" manufactured by Nippon Oil & Fats Co., Ltd. {α,α'-bis(t-butylperoxy-m-isopropyl)benzene} <(C) Low molecular weight component> *5: "A-DCP" tricyclodecane dimethanol diacrylate manufactured by Shin-Nakamura Chemical Co., Ltd. *6: "TAIC" triallyl isocyanurate manufactured by Mitsubishi Chemical Corporation <Elastomer> *7: Asahi Kasei Corporation's "Tuftec H1051" <Filler> *8: Admatechs Co., Ltd. "SC2050-HNF" silica slurry, solid content 70% by mass, dispersion medium cyclohexanone [Industrial Applicability]

[0112] The resin composition, dry film, and cured product of the present invention can suppress swelling of the insulating layer even when cured in an atmospheric environment, and therefore can be used as an interlayer insulating material for printed wiring boards built into electronic devices.

Claims

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

2. The resin composition according to claim 1, further comprising (C) a low-molecular-weight component having a radically polymerizable functional group and a molecular weight of 1,000 or less.

3. 2. The resin composition according to claim 1, wherein the radically 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. 2. The resin composition according to claim 1, wherein the radical polymerization initiator (B) contains a peroxide structure (excluding a structure represented by —O—O—H) or an oxime ester structure.

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

6. 2. The resin composition according to claim 1, wherein the weight average molecular weight Mw of the resin (A) is 2,000 or more.

7. A dry film comprising a resin layer formed from the resin composition according to claim 1.

8. 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 , obtained by curing the resin composition or the resin layer in an atmospheric environment.

Images