Photosensitive thermosetting resin composition, dry film, cured product, and electronic component comprising cured product

Abstract

Provided are a photosensitive thermosetting resin composition, a dry film, a cured product, and an electronic component comprising the cured product, which resin composition has good ink characteristics and can further improve the whitening resistance, heat resistance, crack resistance, pencil hardness, CTI value and wear resistance of a cured film formed therefrom. The photosensitive thermosetting resin composition is composed of a resin composition comprising at least two components. The photosensitive thermosetting resin composition comprises: (A) a carboxyl-containing resin, (B) an epoxy resin, (C) a photopolymerization initiator, (D) a photosensitive monomer, and (E) polytetrafluoroethylene micro-powder, wherein the carboxyl-containing resin (A) and the photopolymerization initiator (C), and the epoxy resin (B) and the photosensitive monomer (D) are respectively contained in different resin compositions, and the median particle size D50 of the polytetrafluoroethylene micro-powder (E) is 2.5 μm or more, but 12 μm or less.

Description

Photosensitive thermosetting resin composition, dry film, cured product, and electronic component having the cured product Technical Field

[0001] The present invention relates to a photosensitive thermosetting resin composition, a dry film, a cured product, and an electronic component having the cured product. Background Art

[0002] In the formation of permanent coatings such as solder resist layers in the manufacture of printed circuit boards (PCB boards), solder resists (also known as solder resist inks) in the form of curable resin compositions are generally used. As such curable resin compositions, dry film-type compositions and liquid compositions have been developed. In addition, for semiconductor devices used in electrical products and vehicles under harsh conditions such as moisture, high temperature and high pressure, such as PCB boards for air conditioners, water heaters, and washing machines, and charging components for new energy vehicles, when there is moisture or dirt on the surface of the material, leakage (tracking damage) will occur, eventually leading to a short circuit. Therefore, as such solder resists, there is a tendency to use solder resists for high-reliability electronic materials.

[0003] Conventional solder resists have historically had low CTI (Comparative Tracking Index) values. Due to thermal expansion and contraction, they often exhibit poor resistance to cracking from thermal shock and poor reliability in response to environmental changes. Furthermore, to enhance electrical safety, protect copper circuits, and maintain aesthetics, solder resists must also possess excellent hardness and wear resistance.

[0004] Patent Document 1 discloses a friction-resistant and scratch-resistant ink. Its filler is primarily talc and / or kaolin, with added barium sulfate and cellulose. Polytetrafluoroethylene (PTFE) powder is not used. It is speculated that its CTI value and abrasion resistance still have room for improvement. Patent Document 2 discloses a wave-transmitting protective composite material. The Teflon coating layer is used to protect the substrate layer and the ink layer, and is not added or used as an ink component.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: CN111117343A

[0008] Patent Document 2: CN116023821A

[0009] Summary of the Invention

[0010] Technical Problems to be Solved by the Invention

[0011] In recent years, the demands placed on electronic devices in areas such as smart homes and new energy vehicles have continued to rise. Consequently, there is a desire for PCB solder resists that, while maintaining excellent ink performance, produce cured films with high CTI values ​​and high abrasion resistance, while also improving properties such as whitening resistance, heat resistance, crack resistance, and pencil hardness.

[0012] Therefore, an object of the present invention is to provide a photosensitive thermosetting resin composition having excellent ink properties and further improved whitening resistance, heat resistance, crack resistance, pencil hardness, CTI value, and abrasion resistance of the formed cured film.

[0013] A further object of the present invention is to provide a dry film and a cured product having excellent properties as described above, obtained by using such a photosensitive thermosetting resin composition, and a printed wiring board formed of the dry film and a cured film of a solder resist or the like as the cured product.

[0014] Solutions for solving problems

[0015] The present inventors have conducted intensive studies and have found that the above-mentioned problems can be solved by the following photosensitive thermosetting resin composition.

[0016] The photosensitive thermosetting resin composition is composed of at least a two-component system resin composition, characterized in that the photosensitive thermosetting resin composition contains: (A) a carboxyl group-containing resin, (B) an epoxy resin, (C) a photopolymerization initiator, (D) a photosensitive monomer, and (E) polytetrafluoroethylene powder.

[0017] The (A) carboxyl group-containing resin and the (C) photopolymerization initiator are contained in different resin compositions from the (B) epoxy resin and the (D) photosensitive monomer.

[0018] The present invention has been completed by providing that the median particle size D50 of the polytetrafluoroethylene fine powder (E) is 2.5 μm or more and 12 μm or less.

[0019] Among them, a preferred embodiment of the present invention relates to a photosensitive thermosetting resin composition, characterized in that the (A) carboxyl-containing resin, the (C) photopolymerization initiator and the (E) polytetrafluoroethylene powder, and the (B) epoxy resin and the (D) photosensitive monomer are respectively contained in different resin compositions.

[0020] Furthermore, a preferred embodiment of the present invention relates to a photosensitive thermosetting resin composition, wherein the median particle size D50 of the polytetrafluoroethylene fine powder (E) is 3 μm or more and 10 μm or less.

[0021] Furthermore, a preferred embodiment of the present invention relates to a photosensitive thermosetting resin composition, wherein the content of the (E) polytetrafluoroethylene fine powder is 5 to 20 wt % based on the total weight of the photosensitive thermosetting resin composition as a solid content.

[0022] Furthermore, a more preferred embodiment of the present invention relates to a photosensitive thermosetting resin composition characterized by further comprising (F) an inorganic filler, wherein the (F) inorganic filler is an inorganic filler other than the (E) polytetrafluoroethylene fine powder.

[0023] Furthermore, a more preferred embodiment of the present invention relates to a photosensitive thermosetting resin composition, wherein the specific gravity of the inorganic filler (F) is 3.5 or more.

[0024] Furthermore, a more preferred embodiment of the present invention relates to a photosensitive thermosetting resin composition, wherein the (F) inorganic filler is barium sulfate.

[0025] Another aspect of the present invention relates to a dry film characterized by having a resin layer obtained by applying the above-mentioned photosensitive thermosetting resin composition on a carrier film and drying the resultant.

[0026] Still another embodiment of the present invention relates to: a cured product characterized in that it is obtained by curing the above-mentioned photosensitive thermosetting resin composition; a cured product characterized in that it is obtained by curing the resin layer of the above-mentioned dry film; and an electronic component characterized in that it comprises these cured products.

[0027] Effects of the Invention

[0028] According to the present invention, a photosensitive thermosetting resin composition can be provided that has excellent ink properties and further improves the whitening resistance, heat resistance, crack resistance, pencil hardness, CTI value, and abrasion resistance of the formed cured film.

[0029] Furthermore, the present invention can provide a dry film and cured product having excellent properties as described above obtained by using such a photosensitive thermosetting resin composition, and an electronic component such as a printed wiring board formed from the dry film and a cured film of a solder resist or the like as the cured product. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a photograph showing cracking (NG) of a solder resist film for evaluating thermal shock resistance in Examples.

[0031] FIG. 2 is a photograph showing that the solder resist film used for evaluating thermal shock resistance in Examples was not cracked (OK). DETAILED DESCRIPTION

[0032] The photosensitive thermosetting resin composition of the present invention is preferably composed of at least a two-component resin composition. For example, a two-component system can be employed, wherein one resin composition serves as a base composition and the other resin composition serves as a curing agent composition. In this case, for example, it is preferred that the base composition comprises at least (A) a carboxyl group-containing resin and (C) a photopolymerization initiator, and the curing agent composition comprises at least (B) an epoxy resin and (D) a photosensitive monomer.

[0033] Here, from the viewpoint of preventing chemical reactions during storage and ensuring good dispersibility and printability of the resin composition of the present invention, it is preferred that (A) the carboxyl group-containing resin and (B) the epoxy resin are directly contained in separate compositions, and (D) the photosensitive monomer and (C) the photopolymerization initiator are directly contained in separate compositions.

[0034] Hereinafter, each component constituting the photosensitive thermosetting resin composition of the present invention will be described.

[0035] (A) Carboxyl-containing resin

[0036] As the carboxyl group-containing resin (A) used in the present invention, known resins containing ethylenically unsaturated double bonds in their molecules for imparting alkali developability can be used. From the perspectives of photocurability and development resistance, carboxyl group-containing resins containing ethylenically unsaturated double bonds in their molecules are particularly preferred. Furthermore, it is more preferred that the unsaturated double bonds be derived from acrylic acid, methacrylic acid, or derivatives thereof. Specific examples of the carboxyl group-containing resin (A) are shown below.

[0037] (1) Carboxyl group-containing vinyl ester resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with one or more other compounds having unsaturated double bonds;

[0038] (2) Carboxyl group-containing vinyl ester resins obtained by adding an ethylenically unsaturated group as a pendant group to a copolymer of an unsaturated carboxylic acid such as (meth)acrylic acid and one or more other compounds having an unsaturated double bond, using a compound having an epoxy group and an unsaturated double bond, such as glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, or (meth)acryloyl chloride;

[0039] (3) Carboxyl group-containing vinyl ester resins obtained by reacting a copolymer of a compound having an epoxy group and an unsaturated double bond, such as glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate, and another compound having an unsaturated double bond, with an unsaturated carboxylic acid, such as (meth)acrylic acid, and reacting a polybasic acid anhydride with the resulting secondary hydroxyl group;

[0040] (4) Carboxyl group-containing vinyl ester resins obtained by reacting a copolymer of an acid anhydride having an unsaturated double bond, such as maleic anhydride, and another compound having an unsaturated double bond, with a compound having a hydroxyl group and an unsaturated double bond, such as 2-hydroxyethyl (meth)acrylate;

[0041] (5) Carboxyl group-containing vinyl ester resins obtained by reacting a polyfunctional epoxy compound with an unsaturated monocarboxylic acid and reacting a saturated or unsaturated polybasic acid anhydride with the resulting hydroxyl group;

[0042] (6) A vinyl ester resin containing hydroxyl groups and carboxyl groups obtained by reacting a hydroxyl-containing polymer such as a polyvinyl alcohol derivative with a saturated or unsaturated polybasic acid anhydride, and then reacting a compound having an epoxy group and an unsaturated double bond in one molecule with the resulting carboxylic acid;

[0043] (7) a carboxyl group-containing vinyl ester resin obtained by reacting a reaction product of a polyfunctional epoxy compound and an unsaturated monocarboxylic acid with a compound having at least one alcoholic hydroxyl group and one reactive group other than the alcoholic hydroxyl group that reacts with an epoxy group in one molecule, with a saturated or unsaturated polybasic acid anhydride;

[0044] (8) a carboxyl group-containing vinyl ester resin obtained by reacting an unsaturated monocarboxylic acid with a polyfunctional oxetane compound having at least two oxetane rings in one molecule, and reacting a saturated or unsaturated polybasic acid anhydride with the primary hydroxyl group in the resulting modified oxetane resin;

[0045] (9) A carboxyl-containing vinyl ester resin obtained by reacting an unsaturated monocarboxylic acid with a polyfunctional epoxy resin and then with a polyacid anhydride to obtain a carboxyl-containing resin, further reacting the resin with a compound having one oxirane ring and one or more ethylenically unsaturated groups in the molecule;

[0046] (10) Carboxyl group-containing vinyl ester resins obtained by reacting a bifunctional epoxy compound with an unsaturated monocarboxylic acid and reacting a saturated or unsaturated polybasic acid anhydride with the generated hydroxyl group;

[0047] (11) Carboxyl group-containing vinyl ester resins obtained by reacting a polyfunctional epoxy resin such as a phenol novolac epoxy resin, a cresol novolac epoxy resin, a bisphenol A cresol novolac epoxy resin, or a dicyclopentadiene cresol novolac epoxy resin with (meth)acrylic acid, and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains;

[0048] (12) a carboxyl group-containing vinyl ester resin obtained by reacting a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the polyfunctional epoxy resin in (11) with (meth)acrylic acid and adding a polybasic acid anhydride to the generated hydroxyl groups;

[0049] (13) Carboxyl group-containing vinyl ester resins obtained by adding a cyclic ether such as ethylene oxide or a cyclic carbonate such as propylene carbonate to a polyfunctional phenol compound such as a novolac resin, partially esterifying the resulting hydroxyl groups with (meth)acrylic acid, and reacting the remaining hydroxyl groups with a polybasic acid anhydride; and

[0050] (14) Carboxyl group-containing vinyl ester resins obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate or monomethylglycidyl (meth)acrylate, to any of the resins described above (11) to (13).

[0051] Particularly preferred among these examples are cresol novolac type and phenol novolac type, and the carboxyl group-containing vinyl ester resins of (5), (11), (12), (13), and (14) described above.

[0052] It should be noted that, in this specification, (meth)acrylate is a term that collectively refers to acrylate, methacrylate, and a mixture thereof, and the same applies to other similar expressions.

[0053] Since the carboxyl group-containing resin (A) described above has a plurality of free carboxyl groups on the side chains of the main chain polymer, it can be developed with a dilute alkaline aqueous solution.

[0054] The acid value of the carboxyl group-containing resin (A) is preferably in the range of 40 to 200 mgKOH / g, more preferably in the range of 45 to 120 mgKOH / g. If the acid value of the carboxyl group-containing resin is less than 40 mgKOH / g, alkali development becomes difficult. On the other hand, if the acid value exceeds 200 mgKOH / g, dissolution of the exposed portion by the developer is promoted, resulting in thinner lines than desired. In some cases, the exposed and unexposed portions are dissolved and peeled off indiscriminately by the developer, making it difficult to draw a normal resist pattern. This is not preferred.

[0055] The weight-average molecular weight of the carboxyl group-containing resin (A) varies depending on the resin backbone, but is generally preferably in the range of 2,000 to 150,000, more preferably 5,000 to 100,000. A weight-average molecular weight of less than 2,000 may result in poor application to a substrate and dryness (tack-free properties) after drying. Furthermore, the moisture resistance of the coating film after exposure may deteriorate, film loss may occur during development, and resolution may significantly deteriorate. On the other hand, a weight-average molecular weight exceeding 150,000 may result in significantly poor developability and poor storage stability.

[0056] (B) Epoxy resin

[0057] (B) The epoxy resin functions as a thermosetting component in the photosensitive thermosetting resin composition to form a cured product.

[0058] As such an epoxy resin (B), a well-known and commonly used multifunctional epoxy resin having at least two epoxy groups in one molecule can be used.

[0059] The epoxy resin (B) may be in a liquid, solid, or semi-solid state.

[0060] As the multifunctional epoxy resin, preferably bisphenol A type epoxy resin; brominated epoxy resin; novolac type epoxy resin; bisphenol F type epoxy resin; hydrogenated bisphenol A type epoxy resin; glycidylamine type epoxy resin; hydantoin type epoxy resin; alicyclic epoxy resin; trishydroxyphenylmethane type epoxy resin; bixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin; bisphenol A novolac type epoxy resin; tetrahydroxyphenylethane type epoxy resin; Resin; heterocyclic epoxy resin; diglycidyl phthalate resin; tetraglycidyl ditoluoyl ethane resin; naphthyl-containing epoxy resin; epoxy resin having a dicyclopentadiene skeleton; glycidyl methacrylate copolymer epoxy resin; copolymerized epoxy resin of cyclohexylmaleimide and glycidyl methacrylate; epoxy-modified polybutadiene rubber derivative; CTBN-modified epoxy resin, epoxy resin having an isocyanurate ring, etc., but of course not limited to these.

[0061] These epoxy resins can be used alone or in combination of two or more.

[0062] The "solid or semi-solid epoxy resin at room temperature" in the component (B) can also be a well-known commonly used one. For example, examples of epoxy resins that are solid at room temperature include bisphenol A epoxy resin (jER1001 manufactured by Mitsubishi Chemical Corporation, 128E manufactured by Nan Ya Plastics Co., Ltd.), bisphenol F epoxy resin (jER4004P manufactured by Mitsubishi Chemical Corporation), naphthalene epoxy resin (HP-4700 manufactured by DIC Corporation), multifunctional solid epoxy resin containing a naphthalene skeleton (NC-7000 manufactured by Nippon Kayaku Co., Ltd.), trisphenol epoxy resin (EPPN-502H manufactured by Nippon Kayaku Co., Ltd.), multifunctional solid epoxy resin containing a dicyclopentadiene skeleton (Epiclon manufactured by DIC Corporation), and epoxy resins having a styrene base. HP-7200), phosphorus-containing epoxy resin (TX0712 manufactured by Nippon Steel & Sumikin Chemicals Corporation), tris(2,3-epoxypropyl)isocyanurate (TEPIC manufactured by Nissan Chemical Industries, Ltd.); as epoxy resins that are semi-solid at room temperature, bisphenol A type epoxy resin (jER834 manufactured by Mitsubishi Chemical Corporation), naphthalene type epoxy resin (HP-4032 manufactured by DIC Corporation), etc. can be cited.

[0063] Here, in the present invention, being solid or semi-solid at room temperature means being solid or semi-solid at 15° C. Determination of solid or semi-solid can be made in accordance with Annex 2, "Method for Confirming Liquid State," of the Ministerial Ordinance concerning the Test and Properties of Dangerous Substances (Ministry of Home Affairs Ordinance No. 1 of 1991).

[0064] As the biphenyl-type epoxy resin in component (B), a well-known and commonly used multifunctional epoxy resin having a biphenyl skeleton can be used. Examples thereof include multifunctional solid epoxy resins containing a biphenyl skeleton (NC-3000H and NC-3000 manufactured by Nippon Kayaku Co., Ltd.) and biphenyl-type epoxy resins (YX-4000 and YL-6121HA manufactured by Mitsubishi Chemical Corporation).

[0065] Examples of the novolac-type epoxy resin in component (B) include cresol novolac-type epoxy resin (Epiclon N-690 manufactured by DIC Corporation), phenol novolac-type epoxy resin (Epiclon N-770 manufactured by DIC Corporation, jER152 manufactured by Mitsubishi Chemical Corporation), and bisphenol A novolac-type epoxy resin (BNE200D75 manufactured by Shanghai Hongze Chemical Co., Ltd.).

[0066] Examples of the epoxy resin having an isocyanurate ring in the component (B) include triglycidyl isocyanurate epoxy resin (TGIC-G manufactured by Shanghai Xindi Chemical Co., Ltd.).

[0067] The content of the epoxy resin (B) described above is preferably approximately 5 to 90 parts by mass, more preferably 8 to 80 parts by mass, and even more preferably 10 to 60 parts by mass relative to 100 parts by mass of the carboxyl group-containing resin (A) in terms of solid content.

[0068] (C) Photopolymerization initiator

[0069] (C) Photopolymerization initiator includes, for example, bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, Bisacylphosphine oxides such as bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, methyl 2,4,6-trimethylbenzoylphenylphosphine oxide, 2-methylbenzoyldiphenylphosphine oxide, isopropyl pivaloylphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc. Monoacylphosphine oxides; 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one and other hydroxyacetophenones; benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin Benzoins such as benzoin isopropyl ether and benzoin n-butyl ether; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2- Acetophenones such as morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholino)phenyl]-1-butanone, N,N-dimethylaminoacetophenone; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, Thioxanthones such as 2-chlorothioxanthone and 2,4-diisopropylthioxanthone; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzoic acid esters such as 4-(dimethylamino)ethyl benzoate, 2-(dimethylamino)ethyl benzoate, and ethyl p-dimethylbenzoate;Oxime esters such as 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime) and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone 1-(O-acetooxime); titanocenes such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1H-pyrrol-1-yl)ethyl)phenyl]titanium; 2-nitrofluorene phenyl disulfide, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. Photopolymerization initiators may be used alone or in combination of two or more.

[0070] The content of the photopolymerization initiator (C) is preferably 5 to 25 parts by mass relative to 100 parts by mass of the carboxyl group-containing resin (A) in terms of solid content. When the content is 5 parts by mass or more, surface curability is improved, while when the content is 25 parts by mass or less, halation is less likely to occur, resulting in good resolution.

[0071] (D) Photosensitive monomer

[0072] The photosensitive thermosetting resin composition capable of forming a cured product of the present invention may contain a known and commonly used photosensitive monomer. The photosensitive monomer (D) may be, for example, a compound having one or more ethylenically unsaturated groups in its molecule. This photosensitive monomer (D) contributes to the photocuring of the epoxy resin (B) upon irradiation with active energy rays (if it contains an ethylenically unsaturated group), thereby curing the photosensitive thermosetting resin composition.

[0073] (D) The photosensitive monomer preferably used in the present invention includes, for example, methyl α-(allyloxymethyl)acrylate, or diol diacrylates such as 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and 1,10-decanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, Tripropylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, diol diacrylates obtained by adding at least one of ethylene oxide and propylene oxide to neopentyl glycol, diol diacrylates such as caprolactone-modified hydroxypivalate neopentyl glycol diacrylate, bisphenol A EO adduct diacrylate, bisphenol A PO adduct diacrylate, tricyclodecane dimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, cyclohexyl diacrylate esters, or bifunctional (meth)acrylates such as methacrylate monomers corresponding thereto, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolmethane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, epichlorohydrin-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, tetramethylolmethane tetraacrylate, ethylene oxide-modified phosphoric acid triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, or polyfunctional acrylates such as silsesquioxane-modified products thereof, or methacrylate monomers corresponding thereto, trifunctional methacrylates, polyfunctional (meth)acrylates such as ε-caprolactone-modified tris(acryloyloxyethyl)isocyanurate, or combinations of two or more thereof.

[0074] The content of the photosensitive monomer (D) is preferably in the range of 2 to 20 parts by mass, more preferably in the range of 4 to 15 parts by mass, relative to 100 parts by mass of the carboxyl group-containing resin (A) in terms of solid content.

[0075] When the content of the photosensitive monomer (D) is within such a range, the photosensitive thermosetting resin composition has sufficient photocurability, patterning during development becomes more favorable, and dryness to touch also becomes favorable.

[0076] (E) Polytetrafluoroethylene powder

[0077] In the present invention, the inventors have discovered through active research that adding a certain amount of polytetrafluoroethylene (PTFE, also known as Teflon, Teflon, etc.) powder in a specific particle size range to a photosensitive thermosetting resin composition can improve the touch drying properties of the solder resist ink coating, while also improving the film indentation on the surface of the solder resist ink coating, improving the heat resistance, crack resistance, and pencil hardness of the cured film, and improving the CTI value and wear resistance of the cured film.

[0078] (E) The median particle size D50 (the particle size value corresponding to the 50% cumulative distribution percentage of the particle size) of the polytetrafluoroethylene micropowder is greater than 2.5 μm and less than 12 μm, preferably greater than 3 μm and less than 10 μm. In addition, D90 (the particle size value corresponding to the 90% cumulative distribution percentage of the particle size) is preferably greater than 5 and less than 15 μm. If the median particle size D50 is less than 2.5 μm, the specific surface area of ​​the smaller particle size polytetrafluoroethylene micropowder is larger, its oil absorption is relatively large, and the viscosity and thixotropic index (TI value) of the ink are relatively large. The ink performance (printability and dispersibility) does not meet the requirements, and the wear resistance of the cured film may also be affected. If the median particle size D50 exceeds 12 μm, due to the increase in particle size, the dispersibility of the composition will also deteriorate, the overall particles of the powder material after dispersion will be larger, and the roughness of the final coating will also increase. Under large roughness, the film indentation on the surface of the ink coating will not meet the requirements, and the wear resistance of the cured film will also be reduced. If polytetrafluoroethylene powder with a larger particle size is used, although it is possible to improve the film indentation on the surface of the ink coating, the printability of the composition will deteriorate.

[0079] The D50 and D90 of the polytetrafluoroethylene fine powder can be obtained using a laser diffraction particle size distribution measuring device and a measuring device based on a dynamic light scattering method. As a measuring device based on the laser diffraction method, Microtrac MT3300EXII manufactured by Microtrac BEL Inc. can be cited, and as a measuring device based on the dynamic light scattering method, Nanotrac Wave II UT151 manufactured by Microtrac BEL Inc. can be cited.

[0080] The appropriate amount of polytetrafluoroethylene powder added to the photosensitive thermosetting resin composition, calculated on a solids basis, is 5% to 20% by weight, more preferably 7% to 18% by weight. Within this range, the CTI value of the cured film is significantly improved, along with enhanced abrasion resistance. A content below 5% by weight may not achieve sufficiently high CTI values ​​and abrasion resistance, while a content exceeding 20% ​​by weight may affect printability and dispersibility.

[0081] The polytetrafluoroethylene powder can be added to any component, for example, the main agent or the curing agent, but is preferably added to the main agent for better printability and dispersibility.

[0082] As long as the particle size of polytetrafluoroethylene micropowder falls within the above-specified range, commonly used commercial products can be used, such as MP1300 from Chemours (formerly DuPont), PTFE-0104A and PTFE-0104S from Nanjing Tianshi New Materials Co., Ltd.

[0083] (F) Inorganic fillers

[0084] In the present invention, the inorganic filler (F) is an inorganic filler other than the polytetrafluoroethylene fine powder (E). Examples thereof include titanium oxide, silicon dioxide, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. From the perspectives of improving mechanical properties, heat resistance, and processability, at least one of talc, silicon dioxide, and barium sulfate is preferred. It is preferred that the main agent contain at least an inorganic filler, and barium sulfate is preferably used as the inorganic filler.

[0085] The inventors of the present invention have also discovered that barium sulfate, due to its high specific gravity (approximately 4.5), easily disperses with polytetrafluoroethylene powder (specific gravity approximately 2.2) in a coating film, thereby achieving excellent dispersibility, printability, and other properties. Silicon dioxide (specific gravity approximately 2.1) and talc (specific gravity approximately 2.7), due to their low specific gravity, easily mix with polytetrafluoroethylene powder, preventing the full effectiveness of the polytetrafluoroethylene powder. Therefore, polytetrafluoroethylene powder and barium sulfate are the most preferred combination.

[0086] Examples of commercially available products of barium sulfate include B-30 (manufactured by Sakai Chemical Industry Co., Ltd.).

[0087] The amount of the inorganic filler (F) blended is preferably in the range of 35 to 200 parts by mass, more preferably in the range of 50 to 150 parts by mass, relative to 100 parts by mass of the carboxyl group-containing resin (A) in terms of solid content. When the amount of the inorganic filler (F) blended is 35 parts by mass or greater, a cured film with superior solder heat resistance, insulation reliability, and heat discoloration resistance tends to be obtained. When the amount of the inorganic filler (F) blended is 200 parts by mass or less, a photosensitive thermosetting resin composition with superior degassing properties, resolution, and deep-section curing properties tends to be obtained.

[0088] (F) The inorganic filler may be a surface-treated one, and more preferably, the surface of the inorganic filler is subjected to a surface treatment capable of introducing a curable reactive group.

[0089] Here, the curable reactive group refers to a group that undergoes a curing reaction with (A) the carboxyl group-containing resin, (B) the epoxy resin, etc., and may be a photocurable reactive group or a thermosetting reactive group. Examples of the photocurable reactive group include methacryloyl, acryloyl, vinyl, and styryl groups, while examples of the thermosetting reactive group include epoxy, amino, hydroxyl, carboxyl, isocyanate, imino, oxetane, mercapto, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, and oxazoline groups.

[0090] The method for introducing curable reactive groups into the surface of the (F) inorganic filler is not particularly limited, and can be introduced using a known conventional method. The surface of the inorganic filler can be treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group. As coupling agents, silane coupling agents, titanium coupling agents, zirconium coupling agents, aluminum coupling agents, etc. can be used. It should be noted that, as inorganic fillers without a surface treatment having a curable reactive group, for example, silica-alumina surface treatment, titanate coupling agent treatment, aluminate coupling agent treatment, organically treated inorganic fillers, etc. can be cited.

[0091] The average particle size (D50) of the inorganic filler (F) is 2000 nm or less, more preferably 1200 nm or less. The lower limit thereof is preferably 0.1 nm or more in terms of the average particle size (D50).

[0092] (F) The smaller the average particle size of the inorganic filler, the more diffuse reflection during light irradiation is suppressed, and the micro-processing of the cured product pattern can be facilitated. The average particle size (D50) can be obtained using a laser diffraction particle size distribution measuring device and a measuring device based on a dynamic light scattering method. As a measuring device based on a laser diffraction method, MicrotracMT3300EXII manufactured by MicrotracBEL Inc. can be cited, and as a measuring device based on a dynamic light scattering method, Nanotrac Wave II UT151 manufactured by MicrotracBEL Inc. can be cited.

[0093] solvent

[0094] In the present invention, for general purposes, such as preparing various component systems of the photosensitive thermosetting resin composition and adjusting the viscosity thereof, a solvent may be used in at least one component system.

[0095] The solvent may be a conventional organic solvent, and examples thereof include: ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoether (DPM), dipropylene glycol diethyl ether, and tripropylene glycol monomethyl ether; polyol ethers; organic acid alkyl esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate (CA), butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; polyol esters; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, solvent naphtha, and heavy aromatic solvent naphtha, etc.

[0096] These conventional organic solvents can be used alone or in combination of two or more.

[0097] The content of the conventional solvent in the main agent composition of the photosensitive thermosetting resin composition of the present invention is preferably in the range of 50 to 85 parts by mass, more preferably in the range of 55 to 70 parts by mass, per 100 parts by mass of the carboxyl group-containing resin (A) in terms of solid content. The content of the conventional solvent in the curing agent composition of the photosensitive thermosetting resin composition of the present invention is preferably in the range of 2 to 35 parts by mass, more preferably in the range of 4 to 25 parts by mass.

[0098] Other ingredients

[0099] The photosensitive thermosetting resin composition of the present invention may, of course, contain further additives as other components as necessary within the scope of the object of the present invention.

[0100] Examples of such components include colorants such as pigments and dyes, thermal polymerization inhibitors, thermal curing catalysts, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, antioxidants, volatile agents, antioxidants, antibacterial / antifungal agents, defoaming agents, leveling agents, rheological additives, anti-sag agents, thickeners, adhesion-imparting agents, thixotropy-imparting agents, photoinitiator aids, sensitizers, photobase generators, thermoplastic resins, elastomers, organic fillers, release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, phosphors, and cellulose resins.

[0101] Among them, melamine is preferably added. As an antioxidant, it improves the adhesion between the substrate and the cured film of the thermosetting composition by inhibiting oxidation of the conductor (copper) on the substrate. It also acts as a thermosetting catalyst, promoting the reaction between epoxy groups and carboxyl groups. This can improve the acid and alkali resistance, metal plating resistance, adhesion, and hardness of the cured product formed by the photosensitive thermosetting resin composition.

[0102] The photosensitive thermosetting resin composition of the present invention may optionally contain melamine in at least one of the base composition and the curing agent composition. Adding melamine to the curing agent composition is more preferred to further facilitate the aforementioned effects. The amount of melamine added is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, per 100 parts by mass of the carboxyl group-containing resin (A), calculated as solids.

[0103] The main agent composition and the curing agent composition of the photosensitive thermosetting resin composition of the present invention can be prepared by mixing and dispersing the respective components in predetermined amounts, for example, using a three-roll mill.

[0104] dry film

[0105] A dry film can be produced from the photosensitive thermosetting resin composition of the present invention. The dry film of the present invention comprises a resin layer obtained by coating the photosensitive thermosetting resin composition of the present invention on a carrier film and drying it. To form the dry film, first, in the case of a two-component system, the base composition and curing agent composition are thoroughly mixed to obtain the photosensitive thermosetting resin composition of the present invention. The composition is then diluted to an appropriate viscosity, either directly or as needed with a high-boiling-point solvent. The composition is then applied to a uniform thickness on a carrier film using a comma coater, knife coater, lip coater, rod coater, extrusion coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The applied composition is then dried, typically at a temperature of 50-130°C for 1-30 minutes, to form the resin layer. The coating film thickness is not particularly limited, but is generally selected within the range of 10-150 μm, preferably 20-60 μm, based on the dried film thickness.

[0106] As the carrier film, a plastic film is generally used, for example, polyester films such as polyethylene terephthalate (PET), polyimide films, polyamide-imide films, polypropylene films, polystyrene films, etc. The thickness of the carrier film is not particularly limited, but is generally selected within the range of 10 to 150 μm.

[0107] After forming a resin layer formed from the photosensitive thermosetting resin composition of the present invention on a carrier film, it is preferable to further laminate a removable cover film on the surface of the resin layer to prevent dust from adhering to the surface of the resin layer. Examples of the removable cover film include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The cover film can be any film as long as it is smaller than the adhesion between the resin layer and the carrier film when the cover film is peeled off.

[0108] It should be noted that in the present invention, the photosensitive thermosetting resin composition of the present invention may be applied to the cover film and dried to form a resin layer, and a carrier film may be laminated on the surface of the resin layer. In other words, in the present invention, when producing a dry film, either a carrier film or a cover film may be used as the thin film to which the curable composition of the present invention is applied.

[0109] Here, a tack-free resin layer can also be formed by adjusting the photosensitive thermosetting resin composition of the present invention to a viscosity suitable for the coating method using, for example, a high-boiling-point solvent, and applying it to a substrate by dip coating, flow coating, roll coating, bar coating, screen printing, curtain coating, or the like, followed by volatilization and drying of the high-boiling-point solvent contained in the composition at a temperature of approximately 60 to 100°C (temporary drying). Alternatively, when the composition is applied to a carrier film or cover film, dried, and wound as a thin film, the resin layer can be formed by laminating the composition of the present invention to the substrate using a laminator or the like so that the layer is in contact with the substrate, and then removing the carrier film.

[0110] As the above-mentioned substrate, in addition to printed circuit boards and flexible printed circuit boards with circuits pre-formed from copper or the like, there can also be mentioned: copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc. The copper-clad laminates use materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, and copper-clad laminates for high-frequency circuits using fluorine·polyethylene·polyphenylene ether (polyphenylene oxide)·cyanate ester, etc.

[0111] Cured material

[0112] When forming a cured product using the photosensitive thermosetting resin composition of the present invention, the composition is applied to a substrate, and after the solvent is evaporated and dried, a resin layer is obtained, and the obtained resin layer is exposed (light irradiated) so that the exposed portion (light-irradiated portion) is cured. Specifically, a contact or non-contact method is used, and active energy rays are selectively used for exposure by forming a patterned photomask, or a laser direct exposure machine is used for direct pattern exposure, and an alkaline aqueous solution (such as a 0.3-3% by mass sodium carbonate aqueous solution) is used to develop the unexposed portion, thereby forming a resist pattern. Further heating to a temperature of about 100-180°C and performing thermal curing (post-curing) can form a cured film (cured product) having excellent properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties.

[0113] The volatilization drying or thermal curing when forming the above-mentioned cured product can be carried out, for example, using a hot air circulation drying furnace, IR furnace, hot plate, convection oven, etc. (using a device with a heat source that uses steam to heat the air, a method of making the hot air in the dryer contact by convection, and a method of blowing it onto the support body using a nozzle).

[0114] In addition, as an exposure machine used in the above-mentioned active energy ray irradiation, any device that is equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc. and irradiates ultraviolet rays in the range of 350 to 450 nm can be used. Furthermore, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser using CAD data from a computer) can also be used. As a lamp light source or a laser light source of a direct drawing machine, the maximum wavelength can be in the range of 350 to 410 nm. The exposure amount used for image formation varies depending on the film thickness, etc., and can usually be set to 20 to 1000 mJ / cm 2 , preferably can be set to 20 to 800 mJ / cm 2 within the range.

[0115] Next, in a development step, the dried coating film after the exposure step is treated with a developer to remove unexposed portions of the coating film, thereby forming a patterned film of the curable composition of the present invention.

[0116] Here, as the method used in the development step, an immersion method, a shower method, a spray method, a brush method, etc. can be used. As the developer, a sodium carbonate aqueous solution with a mass concentration of 0.5 to 5% can generally be used. Other alkaline aqueous solutions can also be used, such as alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc.

[0117] In this development step, the temperature of the developer is 20 to 40° C. and the development time is within 180 seconds.

[0118] In the development step, the obtained pattern film may be washed with a rinse solution as needed. As the rinse solution, distilled water, methanol, ethanol, isopropyl alcohol, etc. may be used alone or in combination.

[0119] electronic components

[0120] The present invention can also provide an electronic component comprising the cured product.

[0121] The photosensitive thermosetting resin composition or dry film of the present invention can be used as a protective film, electrical insulation layer, sealing material for printed circuit boards, semiconductor elements, etc., as well as a sealing material for built-in electronic components, a component embedding layer, and an adhesive layer for fixing electronic components. It is particularly suitable for use in semiconductor devices in electrical products and vehicles that are subject to harsh conditions such as humidity, high temperature and high pressure, such as PCB boards for air conditioners, water heaters, and washing machines, and charging components for new energy vehicles.

[0122] It should be noted that the electronic components in the present invention refer to components used in electronic circuits, including active components such as printed circuit boards, transistors, light-emitting diodes, laser diodes, etc., as well as passive components such as resistors, capacitors, inductors, connectors, etc.

[0123] Hereinafter, one embodiment of the present invention will be specifically described based on the examples, but it is of course not intended to limit the scope of the invention according to the claims of the present invention.

[0124] In addition, unless otherwise specified, the "parts" and "%" shown are based on mass.

[0125] Example

[0126] [Synthesis Example: Synthesis of Novolac-Type Carboxyl-Containing Resin]

[0127] 1070 g of an o-cresol novolac-type epoxy resin (EPICLONN-695, manufactured by DIC Corporation, softening point 95°C, epoxy equivalent 214, average number of functional groups 7.6) (glycidyl group number (total number of aromatic rings): 5.0 mol), 360 g (5.0 mol) of acrylic acid, and 1.5 g of hydroquinone were added to 600 g of diethylene glycol monoethyl ether acetate, and the mixture was stirred and uniformly dissolved. Subsequently, 4.3 g of triphenylphosphine was added, and the mixture was heated to 110°C and reacted for 2 hours. The temperature was then raised to 120°C and the reaction was continued for an additional 12 hours. To the resulting reaction solution, 415 g of diethylene glycol monoethyl ether acetate and 456.0 g (3.0 mol) of tetrahydrophthalic anhydride were added, and the mixture was reacted at 110°C for 4 hours. The mixture was then cooled to obtain a carboxyl group-containing vinyl ester resin (varnish). The carboxyl vinyl ester resin (varnish) thus obtained had a solid content concentration of 64% by mass and an acid value of 89 mgKOH / g. Furthermore, the weight-average molecular weight (Mw) of the obtained carboxyl vinyl ester resin was 9000. It should be noted that the weight-average molecular weight of the obtained resin was measured using a high performance liquid chromatograph (HPLC) equipped with a pump LC-6AD manufactured by Shimadzu Corporation and three columns Shodex (registered trademark) KF-804, KF-803, and KF-802 manufactured by Showa Denko K.K.

[0128] [Examples 1 to 2 and Comparative Examples 1 to 6]

[0129] The components shown in Table 1 were pre-mixed in a blender at various blending amounts and then kneaded using a three-roll mill to prepare photosensitive thermosetting resin compositions (two-component systems consisting of a base composition and a curing agent composition) of Examples 1 to 2 and Comparative Examples 1 to 6, respectively.

[0130] [Table 1]

[0131] The components described in Table 1 are as follows.

[0132] *1: (A) Novolac-type carboxyl-containing resin obtained in Synthesis Example, solid content 64%, solvent content (diethylene glycol monoethyl ether acetate (normal solvent)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0133] *2: Rheological additive: Benathix, manufactured by Elementis

[0134] *3: Phthalocyanine blue: FASTOGEN Blue 5380, manufactured by DIC Corporation

[0135] *4: Defoaming agent: KS-66, manufactured by Shin-Etsu Chemical Co., Ltd.

[0136] *5: (C) Photopolymerization initiator: DETX, manufactured by Tianjin Jiuri New Materials Co., Ltd.

[0137] *6: (C) Photopolymerization initiator: #907: α-aminoacetophenone-based photopolymerization initiator (Omnirad 907 manufactured by IGM Resins) (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one)

[0138] *7: Organic solvent: Diethylene glycol monoethyl ether acetate, manufactured by Shanghai Hongze Chemical Co., Ltd.

[0139] *8: Silica: L-300, manufactured by Tosoh Silicon Corporation

[0140] *9: Talc: LMP-100, manufactured by Fuji Talc Industries Co., Ltd.

[0141] *10: Barium sulfate: B-30, manufactured by Sakai Chemical Industry Co., Ltd.

[0142] *11: (E) Polytetrafluoroethylene powder D50: 3-10μm

[0143] *12: Polytetrafluoroethylene powder D50: >20μm

[0144] *13: Polytetrafluoroethylene powder D50: <1μm

[0145] *14: Polytetrafluoroethylene powder D50: 1-2μm

[0146] *15: Polytetrafluoroethylene powder D50: 15-20μm

[0147] *16: (B) Liquid epoxy resin: N-770-75EA, manufactured by DIC Corporation, a novolac-type multifunctional epoxy resin, solid content 75%

[0148] *17: (D) Photosensitive monomer: DPHA, dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.

[0149] *18: Organic solvent: Diethylene glycol monoethyl ether acetate, manufactured by Shanghai Hongze Chemical Co., Ltd.

[0150] *19: Organic solvent: S-150, heavy aromatic solvent naphtha, manufactured by Shanghai Hongze Chemical Co., Ltd.

[0151] *20: Melamine: MELAMINE-JC, manufactured by Shanghai Xindi Chemical Co., Ltd.

[0152] *21: (B) Powdered epoxy resin: TGIC-G, manufactured by Shanghai Xindi Chemical Co., Ltd.

[0153] *22: Barium sulfate: B-30, manufactured by Sakai Chemical Industry Co., Ltd.

[0154] The following tests were performed on the obtained base composition, curing agent composition, and photosensitive thermosetting resin composition obtained by mixing these in Examples and Comparative Examples.

[0155] Dispersibility

[0156] Use a 0-50μm scraper gauge. Wipe the gauge clean before testing. After the solvent has completely evaporated, confirm that there is no residue on the surface. Remove any dust with a static-eliminating brush. With the 0 mark on the gauge table facing the tester, take a small amount of sample and place it above the maximum mark. The amount of sample should be greater than the volume of the gauge's groove. With the blade of the scraper perpendicular to the gauge's groove, press the gauge downward perpendicularly to the gauge's surface. Continue moving the scraper toward the 0 mark at a constant speed (approximately 4 seconds for the entire scraping process).

[0157] Line Assessment

[0158] If lines longer than 5mm appear due to friction between the particles of the sample being tested and the scraper, and three or more lines appear in the same slot and within the same scale range, the upper scale line within the scale range where the lines appear is the reading. If the readings of the left and right slots differ, the larger reading is used as the test result.

[0159] Particle Assessment

[0160] Observe the particles in the channel. If there are 5 or more particles in the same channel and within the same scale range, the upper scale line within the scale range is used as the reading. If the readings of the left and right channels are inconsistent, the larger reading shall prevail as the test result.

[0161] Judgment criteria: If the line evaluation is 15μm or less and the particle evaluation is 35μm or less, the dispersion is judged as good "○";

[0162] Otherwise, the dispersion was judged as poor "×".

[0163] <Printability>

[0164] The photosensitive thermosetting resin composition obtained by thoroughly mixing the main agent composition and the curing agent composition of each of the above-mentioned embodiments and comparative examples was printed using a 100-mesh polyester fiber mesh with a scraper having a hardness of 70-80. The substrate was an FR-4 substrate (solar ink test substrate pattern T-5, T-44). The spacing between the screen and the substrate was approximately 3.2 mm, the scraper angle was 60-80 degrees, the printing speed was 10-20 cm / sec, and the wet film thickness was approximately 35 μm. After printing, the coating surface was visually evaluated for bubbles, craters, and orange peel.

[0165] Judgment criteria: If there are no bubbles, shrinkage holes, orange peel and other phenomena on the coating surface, it is judged as good printability "○";

[0166] Otherwise, the printability was judged as poor "×".

[0167] <Dry to touch>

[0168] The photosensitive thermosetting resin compositions of the above-mentioned embodiments and comparative examples were applied to the entire surface of a copper-clad laminate polished with a polishing roller by screen printing, and dried at 80°C for 30 minutes to prepare a substrate. The dryness to touch of the coating surface was evaluated.

[0169] ○: No stickiness at all, △: Slightly sticky, ×: Sticky

[0170] <Surface film indentation>

[0171] The photosensitive thermosetting resin compositions of the above-mentioned embodiments and comparative examples were applied to the entire surface of a copper-clad laminate that had been polished by a polishing roller by screen printing. The substrate was dried at 80°C for 30 minutes to produce a substrate. After the substrate was completely cooled, it was exposed using a film. After exposure, the film indentation on the coating surface was visually observed.

[0172] Judgment standard: If there is no obvious film indentation on the coating surface, it is judged as good film indentation "○";

[0173] Otherwise, it is judged as the film impression difference "×".

[0174] <Whitening resistance>

[0175] The curable resin compositions of the above-mentioned examples and comparative examples were applied by screen printing to the entire surface of a copper-clad laminate substrate that had been pre-treated by polishing and grinding, dried at 80°C for 30 minutes, and cooled to room temperature to form a resin layer with a thickness of 25 μm. The resin layer was exposed to light using a 7 kW conventional halogen exposure machine (HMW-680GW manufactured by ORC) equipped with a halogen lamp light source at a rate of 400 mJ / cm 2 The entire surface was exposed to an exposure dose of 100 nm, and developed using a 1% mass concentration sodium carbonate aqueous solution at 30°C and a spray pressure of 0.2 MPa for 60 seconds. The composition was then dried (post-cured) in a hot air circulation drying oven adjusted to 150°C for 60 minutes to obtain an evaluation substrate.

[0176] The evaluation substrate coated with rosin flux was immersed in a solder bath pre-set at 288°C for 10 seconds, then directly immersed in boiling water at 100°C for 30 minutes. After removal, the cured film surface was observed to see if it had turned white.

[0177] ○: No whitening

[0178] △: Slightly white

[0179] ×: Severe whitening

[0180] Heat resistance

[0181] The curable resin compositions of the above-mentioned examples and comparative examples were applied by screen printing to the entire surface of a copper-clad laminate substrate that had been pre-treated by polishing and grinding, dried at 80°C for 30 minutes, and cooled to room temperature to form a resin layer with a thickness of 25 μm. The resin layer was exposed to light using a 7 kW conventional halogen exposure machine (HMW-680GW manufactured by ORC) equipped with a halogen lamp light source at a rate of 400 mJ / cm 2 The entire surface was exposed to an exposure dose of 100 nm, and developed using a 1% mass concentration sodium carbonate aqueous solution at 30°C and a spray pressure of 0.2 MPa for 60 seconds. The composition was then dried (post-cured) in a hot air circulation drying oven adjusted to 150°C for 60 minutes to obtain an evaluation substrate.

[0182] The evaluation substrate coated with rosin-based flux was immersed in a solder bath pre-set at 288°C. After the flux was washed with modified alcohol, swelling and peeling of the resist layer were visually evaluated. The evaluation criteria were as follows.

[0183] ○: No peeling was observed even after 10-second immersion was repeated 4 or more times

[0184] △: Slight peeling when repeated 4 or more times of 10-second immersion

[0185] ×: The resist layer is bulged or peeled off when the 10-second immersion is repeated 4 times or less

[0186] <Crack resistance>

[0187] The photosensitive thermosetting resin composition of the embodiment and the comparative example was applied to the entire surface of a substrate having a 2mm copper wire pattern formed thereon by screen printing in a manner to a thickness of 25 μm, and dried at 80°C for 30 minutes in a hot air circulation drying furnace. After cooling to room temperature, the pattern was exposed using a 7KW conventional halogen exposure machine (HMW-680GW manufactured by ORC) equipped with a halogen lamp light source, followed by development for 60 seconds in a 1wt% sodium carbonate aqueous solution, a pressure of 0.2 MPa, and a liquid temperature of 30°C, and then cured at 150°C for 60 minutes in a hot air circulation drying furnace. By using a UV conveyor furnace with a cumulative exposure of 2000mJ / cm 2 The thermal shock cycle test (TCT test) was performed by irradiating the substrate with ultraviolet light under the conditions of 17 resist patterns with right angles. Several evaluation substrates prepared as above were placed in a thermal cycler that cycles the temperature between -40°C (15 minutes) and 125°C (15 minutes) and setting different cycle times. The appearance at each cycle was then observed, and the maximum number of cycles without cracks was recorded (see Figures 1 and 2 for the presence or absence of cracks). The evaluation criteria are shown below.

[0188] ○: No cracks after more than 1000 cycles

[0189] ×: Cracks occurred at less than 1000 cycles

[0190] Pencil hardness

[0191] The photosensitive thermosetting resin composition of the above-mentioned embodiment and comparative example was applied to the entire surface of a copper-clad laminate substrate that had been pre-treated by polishing by screen printing, dried at 80°C for 30 minutes, and cooled to room temperature to form a resin layer with a thickness of 40μm. The resin layer was pattern-exposed using a 7kW conventional halogen exposure machine (HMW-680GW manufactured by ORC) equipped with a halogen lamp light source, followed by development for 60 seconds in a 1wt% sodium carbonate aqueous solution, a pressure of 0.2MPa, and a liquid temperature of 30°C. The composition was then dried (post-cured) for 60 minutes in a hot air circulation drying oven at 150°C to obtain an evaluation substrate. The pencil hardness of the resin surface of the evaluation substrate was measured according to JIS K 5600-5-4, and the measurement results are recorded in Table 1. The evaluation criteria are as follows.

[0192] ◎: Pencil hardness 6H or above

[0193] ○: Pencil hardness 4H or higher and lower than 6H

[0194] △: Pencil hardness is less than 4H

[0195] CTI value

[0196] The photosensitive thermosetting resin composition of the above-mentioned embodiment and comparative example was applied by screen printing to the entire surface of a copper-clad laminate substrate that had been pre-treated by polishing and grinding, dried at 80°C for 30 minutes, and cooled to room temperature to form a resin layer with a thickness of 40μm. For the resin layer, a 7KW conventional halogen exposure machine (ORC HMW-680GW) equipped with a halogen lamp light source was used for pattern exposure, followed by 60 seconds of development in a 1wt% sodium carbonate aqueous solution, a pressure of 0.2MPa, and a liquid temperature of 30°C. The composition was then dried (post-cured) for 60 minutes in a hot air circulation drying oven at 150°C to obtain an evaluation substrate, and the CTI value of the cured film on the substrate surface was measured:

[0197] Measuring equipment: Tracking tester, model SH5240

[0198] Test standard: IEC 60112:2020

[0199] Test solution: 0.1% ammonium chloride (NH4Cl) solution

[0200] Evaluation method: Evaluate the highest test voltage (V) at which the substrate surface coating can withstand a 50-drop test process without causing tracking failure, continuous burning on the sample surface, or operation of the overcurrent device.

[0201] Wear resistance

[0202] The photosensitive thermosetting resin composition of the above-mentioned embodiment and comparative example was applied by screen printing to the entire surface of a copper-clad laminate substrate that had been pre-treated by polishing and grinding, dried at 80°C for 30 minutes, and cooled to room temperature to form a resin layer with a thickness of 40μm. For the resin layer, a 7KW conventional halogen exposure machine (ORC HMW-680GW) equipped with a halogen lamp light source was used for pattern exposure, followed by 60 seconds of development in a 1wt% sodium carbonate aqueous solution, a pressure of 0.2MPa, and a liquid temperature of 30°C. The composition was then dried (post-cured) for 60 minutes in a hot air circulation drying oven at 150°C to obtain an evaluation substrate, and the wear resistance of the cured film on the substrate surface was measured:

[0203] Testing equipment: Reciprocating wear testing machine

[0204] Test standard: ISO 7784-1:2016

[0205] Evaluation method: A CS-10 grinding wheel was used with a load of 500 g / wheel and a speed of 60 rpm. A reciprocating abrasion test was performed 100 times to evaluate the scratches on the surface of the cured film after the test.

[0206] 5. Inconspicuous scratches;

[0207] 4 slightly noticeable scratches;

[0208] 3. There are obvious scratches on the surface, but they are not serious;

[0209] 2. Obvious scratches on the surface;

[0210] 1 Clearly visible scratches

[0211] As shown in Table 1, by using polytetrafluoroethylene powder in a specific particle size range, the photosensitive thermosetting resin compositions of Examples 1 and 2 of the present invention have excellent ink properties (dispersibility, printability, dryness to touch, and film indentation on the ink coating surface), and the cured products have excellent whitening resistance, heat resistance, crack resistance, pencil hardness, CTI value, and abrasion resistance.

[0212] On the other hand, the main agent composition of Comparative Example 1 does not contain polytetrafluoroethylene powder, and the dryness to touch and the film indentation on the ink coating surface are poor. At the same time, the whitening resistance, heat resistance, crack resistance, pencil hardness, CTI value and wear resistance of the cured product are all poor. The polytetrafluoroethylene powder used in Comparative Example 3 has a slightly smaller particle size (D50 = 1-2 μm), and the dispersibility and printability of the composition are poor. The polytetrafluoroethylene powder used in Comparative Example 4 has a slightly larger particle size (D50 = 15-20 μm), and the dispersibility and film indentation on the ink coating surface of the composition are poor, and the wear resistance of the cured product is reduced. In Comparative Example 2, a larger amount of polytetrafluoroethylene powder with a larger particle size (D50> 20 μm) is used. Although the film indentation on the ink coating surface is improved compared with Comparative Example 4, the printability of the composition deteriorates, and the dispersibility of the composition and the wear resistance of the cured product are still poor. Comparative Example 5, while containing the same total amount of inorganic filler as Example 2, used a higher amount of low-density talc instead of polytetrafluoroethylene powder. This resulted in poor printability, poor dry-to-touch properties, and poor film indentation on the ink coating surface. The cured film also exhibited poor blushing resistance, heat resistance, pencil sharpening, and abrasion resistance. Comparative Example 6, which used a higher amount of polytetrafluoroethylene powder with a smaller particle size (D50 < 1 μm), showed improved abrasion resistance compared to Comparative Example 2, which used a larger polytetrafluoroethylene powder. However, the dispersibility and printability of the composition remained poor.

[0213] It can be seen that the photosensitive thermosetting resin composition ink of the present invention has excellent properties. At the same time, the formed cured film has further improved whitening resistance, heat resistance, crack resistance, pencil hardness, CTI value and wear resistance. It is particularly suitable for use in electrical products, semiconductor devices of vehicles, etc. under harsh conditions such as humidity, high temperature and high pressure, such as PCB boards of air conditioners, water heaters, washing machines, and charging components of new energy vehicles.

Claims

1. A photosensitive thermosetting resin composition, which is composed of a resin composition of at least a two-component system, characterized in that: The photosensitive thermosetting resin composition comprises: (A) a carboxyl group-containing resin, (B) an epoxy resin, (C) a photopolymerization initiator, (D) a photosensitive monomer, and (E) polytetrafluoroethylene powder. The (A) carboxyl group-containing resin and the (C) photopolymerization initiator are contained in different resin compositions from the (B) epoxy resin and the (D) photosensitive monomer. The median particle size D50 of the polytetrafluoroethylene fine powder (E) is not less than 2.5 μm and not more than 12 μm.

2. The photosensitive thermosetting resin composition according to claim 1, characterized in that: The (A) carboxyl group-containing resin, the (C) photopolymerization initiator and the (E) polytetrafluoroethylene powder are contained in different resin compositions from the (B) epoxy resin and the (D) photosensitive monomer.

3. The photosensitive thermosetting resin composition according to claim 1 or 2, characterized in that: The median particle size D50 of the polytetrafluoroethylene fine powder (E) is not less than 3 μm and not more than 10 μm.

4. The photosensitive thermosetting resin composition according to claim 1 or 2, characterized in that: The content of the (E) polytetrafluoroethylene fine powder is 5 to 20 wt % based on the total weight of the solid content of the photosensitive thermosetting resin composition.

5. The photosensitive thermosetting resin composition according to claim 1 or 2, characterized in that: The invention further comprises (F) an inorganic filler, wherein the inorganic filler (F) is an inorganic filler other than the (E) polytetrafluoroethylene fine powder.

6. The photosensitive thermosetting resin composition according to claim 5, characterized in that: The specific gravity of the (F) inorganic filler is 3.5 or more.

7. The photosensitive thermosetting resin composition according to claim 5, characterized in that: The (F) inorganic filler is barium sulfate.

8. A dry film, characterized in that: The present invention has a resin layer obtained by applying the photosensitive thermosetting resin composition according to any one of claims 1 to 7 onto a carrier film and drying the resultant.

9. A solidified product, characterized in that: This is obtained by curing the photosensitive thermosetting resin composition according to any one of claims 1 to 7.

10. A solidified product, characterized in that: This is obtained by curing the resin layer of the dry film according to claim 8.

11. An electronic component, characterized in that: A cured product according to claim 9 or 10.

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