JP7574074B2 - CURABLE RESIN COMPOSITION, DRY FILM, CURED PRODUCT, AND ELECTRONIC COMPONENT - Google Patents

Description

The present invention relates to a curable resin composition and a dry film thereof, a cured product thereof, and an electronic component having the cured product.

In printed wiring boards, a solder resist is formed on a substrate having a conductor layer of a circuit pattern. Various curable resin compositions have been proposed as materials for permanent protective films, such as interlayer insulating materials for printed wiring boards and coverlays for flexible printed wiring boards, in addition to solder resists.

Of these, many of these are alkaline development type curable resin compositions that use a dilute alkaline aqueous solution as the developer, due to environmental considerations, but there are also curable resin compositions for screen printing, in which the ink is pushed through the mesh of a printing plate onto a panel for printing.

Such curable resin compositions are used for various purposes, and one example is a highly reflective white curable resin composition that is suitable as an insulating layer for printed wiring boards on which light-emitting devices such as light-emitting diodes (LEDs) are mounted. By making the insulating layer highly reflective, the efficiency of using light from light sources such as LEDs can be improved. To make a white curable resin composition, it is common to add a white colorant such as titanium dioxide. However, when the color is white, there is a problem that deterioration is easily visible when the color changes due to heat. This problem is not limited to white cured products, but also applies to transparent cured products and cured products with a small amount of colorant added.

Patent Document 1 discloses a photosensitive and thermosetting resin composition containing Irganox 1010 as a phenolic antioxidant. This resin composition exhibits a yellowing suppression effect under heating conditions that simulate solder reflow during manufacturing.

JP 2012-108523 A

However, although the resin composition of Patent Document 1 shows a yellowing suppression effect under heating conditions during manufacturing, this effect cannot be said to be sufficient as a yellowing suppression effect. Specifically, the inventors' investigations have revealed that in printed wiring boards on which light-emitting elements such as light-emitting diodes (LEDs) are mounted, there is a problem of long-term yellowing due to exposure of an insulating layer using a curable resin composition to light from an LED light source for a long period of time.

In view of the above problems, the object of the present invention is to provide a curable resin composition that can prevent not only yellowing during thermal curing but also long-term yellowing due to ultraviolet rays, a dry film having a resin layer obtained from the curable resin composition, a cured product of these, and an electronic component having the cured product.

The inventors conducted extensive research to achieve the above objective. As a result, they discovered that the above objective could be achieved by using a specific combination of antioxidants in a curable resin composition, and thus completed the present invention.

That is, the above object of the present invention is to
A composition comprising (A) a hindered phenol-based antioxidant and (B) a thermosetting component,
(A) a hindered phenol-based antioxidant,
(A1) a hindered phenol-based antioxidant having an ester skeleton and a vapor pressure at 20° C. of 1.0×10 ⁻⁷ Pa or less;
(A2) a hindered phenol-based antioxidant having an isocyanurate structure;
It has been found that the above object can be achieved by a curable resin composition comprising at least

The curable resin composition of the present invention also preferably contains (C) an alkali-soluble resin and (D) a photopolymerization initiator, and it is more preferable that (C) the alkali-soluble resin contains a carboxyl group-containing fluororesin.

Furthermore, the blending amount of each of (A1) the hindered phenol-based antioxidant having an ester skeleton and having a vapor pressure of 1.0 × 10 ^-7 Pa or less at 20°C and (A2) the hindered phenol-based antioxidant having an isocyanurate structure is preferably 0.1 parts by mass or more and 5.0 parts by mass or less, based on 100 parts by mass of the total of (B) the thermosetting component and (C) the alkali-soluble resin, calculated on a solid content basis.

Further, the above object is to provide a dry film having the curable resin composition of the present invention as a resin layer,
The above object can also be achieved by a cured product obtained by curing the curable resin composition or the dry film resin of the present invention, and an electronic part having the cured product.

The curable resin composition of the present invention can suppress yellowing of the curable resin composition during thermal curing and yellowing of the cured product due to ultraviolet light irradiation after curing. Therefore, when applied to cured products that are white, transparent, translucent, or have a small amount of colorant added, for example, it is possible to form cured products that are less affected by yellowing.

<Curable resin composition>
The curable resin composition of the present invention comprises:
A composition comprising (A) a hindered phenol-based antioxidant and (B) a thermosetting component,
(A) a hindered phenol-based antioxidant,
(A1) a hindered phenol-based antioxidant having an ester skeleton and a vapor pressure at 20° C. of 1.0×10 ⁻⁷ Pa or less;
(A2) a hindered phenol-based antioxidant having an isocyanurate structure;
At least

[(A) Hindered phenol-based antioxidant]
In order to suppress yellowing due to deterioration caused by heat applied to the coating film and yellowing due to deterioration caused by exposure of the cured product to ultraviolet light for a long period of time, the hindered phenol-based antioxidant (A1) is blended in the curable resin composition in a form containing at least a hindered phenol-based antioxidant having an ester skeleton and a vapor pressure of 1.0×10 ⁻⁷ Pa or less at 20° C., and a hindered phenol-based antioxidant (A2) having an isocyanurate structure. By using the components (A1) and (A2) in combination, yellowing during heat curing when forming a cured product can be suppressed, and yellowing due to exposure of the cured product to ultraviolet light for a long period of time can also be suppressed. Due to these actions, a white cured product with low yellowing and high reflectance can be maintained even after exposure to ultraviolet light for a long period of time.

(A1) Vapor pressure at 20°C is 1.0 x ^10-7 Examples of the hindered phenol-based antioxidant having an ester skeleton and a viscosity of 100 MPa or less include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propioquinyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, ethylene bis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate), hexamethylene bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and the like.

(A1) Commercially available hindered phenol antioxidants having a vapor pressure at 20° C. of 1.0×10 ⁻⁷ Pa or less and an ester skeleton include, but are not limited to, ADK STAB AO-60 and ADK STAB AO-80 (all manufactured by ADEKA CORPORATION), Irganox 245, Irganox 259, and Irganox 1010 (all manufactured by BASF Japan Ltd.), and Sumilizer GA-80 (manufactured by Sumitomo Chemical Co., Ltd.).

Furthermore, as the hindered phenol-based antioxidant (A1) having an ester skeleton and a vapor pressure of 1.0×10 ⁻⁷ Pa or less at 20° C., it is preferable to use one having a vapor pressure of 5.0×10 ⁻⁸ Pa or less at 20° C. from the viewpoint of preventing volatilization of the hindered phenol-based antioxidant from the curable resin composition due to heating or warming, and it is more preferable to use one having a vapor pressure of 1.0×10 ⁻⁹ Pa or less at 20° C.

のイソシアヌレート構造を有するヒンダードフェノール系酸化防止剤であればどのようなものであってもよいが、
好ましくは、式（２）

（式（２）中、Ｒ_１、Ｒ_２、Ｒ_３は、それぞれ、水素原子、炭素数１個以上４個以下の直鎖状または分岐状の炭化水素基、および３，５－ジ－ｔｅｒｔ－ブチル－４－ヒドロキシベンジル基である（ただし、Ｒ_１～Ｒ_３の少なくとも１個が３，５－ジ－ｔｅｒｔ－ブチル－４－ヒドロキシベンジル基である））
で表される化合物であり、なかでも、Ｒ_１～Ｒ_３が全て３，５－ジ－ｔｅｒｔ－ブチル－４－ヒドロキシベンジル基である式（２）で表される化合物であることが特に好ましい。 (A2) The hindered phenol-based antioxidant having an isocyanurate structure is preferably a phenol-based antioxidant represented by the formula (1):

Any hindered phenol-based antioxidant having an isocyanurate structure may be used.
Preferably, the formula (2)

In formula (2), R ₁ , R ₂ , and R ₃ are each a hydrogen atom, a linear or branched hydrocarbon group having from 1 to 4 carbon atoms, and a 3,5-di-tert-butyl-4-hydroxybenzyl group (provided that at least one of R ₁ to R ₃ is a 3,5-di-tert-butyl-4-hydroxybenzyl group).
Among them, a compound represented by formula (2) in which all of R ₁ to R ₃ are 3,5-di-tert-butyl-4-hydroxybenzyl groups is particularly preferred.

(A2) Commercially available hindered phenol-based antioxidants having an isocyanurate structure include Adeka STAB AO-20 (manufactured by ADEKA Corporation), Irganox 3114 (manufactured by BASF Japan Ltd.), K-NOX 014 (manufactured by SANYO TRADING CO., LTD.), and Cyanox 1790 (manufactured by Nippon Cytec Industries Co., Ltd.).

The blending amount of the (A1) hindered phenol-based antioxidant having an ester skeleton and having a vapor pressure of 1.0 × 10 ^-7 Pa or less at 20°C and the (A2) hindered phenol-based antioxidant having an isocyanurate structure is preferably 0.1 to 5.0 parts by mass, more preferably 0.2 to 4 parts by mass, and even more preferably 0.4 to 2 parts by mass, based on 100 parts by mass in total of the (B) thermosetting component and the (C) alkali-soluble resin (100 parts by mass of the (B) thermosetting component in the case where the (C) alkali-soluble resin is not contained), calculated on a solid content basis.

When the blending amounts of (A1) the hindered phenol-based antioxidant having an ester skeleton and having a vapor pressure of 1.0 × 10 ^-7 Pa or less at 20°C and (A2) the hindered phenol-based antioxidant having an isocyanurate structure are each 0.1 part by mass or more per 100 parts by mass of the total of (B) the thermosetting component and (C) the alkali-soluble resin (100 parts by mass of (B) the thermosetting component in the case where (C) the alkali-soluble resin is not contained), calculated as solid content, an effect of making yellowing less noticeable in white, transparent, translucent curable resin compositions and those containing small amounts of pigments and colorants can be expected.

In addition, the amount of each of the hindered phenol-based antioxidant (A1) having an ester skeleton and a vapor pressure at 20°C of 1.0 × 10 ^-7 Pa or less and the hindered phenol-based antioxidant (A2) having an isocyanurate structure is 5 parts by mass or less, calculated as solid content, per 100 parts by mass of the total of the thermosetting component (B) and the alkali-soluble resin (C) (100 parts by mass of the thermosetting component (B) in the case where the alkali-soluble resin (C) is not contained), can be expected to have an effect of preventing yellowing caused by the hindered phenol-based antioxidant.

[(B) Thermosetting component]
The thermosetting component (B) is added to thermally cure the curable resin composition of the present invention.

As the thermosetting component, known and commonly used thermosetting components such as isocyanate compounds, amino resins, maleimide compounds, benzoxazine resins, carbodiimide resins, cyclocarbonate compounds, epoxy compounds, polyfunctional oxetane compounds, and episulfide resins can be used.

In the present invention, epoxy resins are particularly preferred.

As the epoxy resin, a known and commonly used multifunctional epoxy resin having at least two epoxy groups in one molecule can be used. The epoxy resin may be liquid, solid, or semi-solid. Here, liquid, solid, and semi-solid each refer to the state of the epoxy resin at 30°C.

Examples of epoxy resins include jER828, jER834, jER1001, and jER1004 manufactured by Mitsubishi Chemical Corporation, EPICLON 840, 850, 850-S, 1050, and 2055 manufactured by DIC Corporation, Epototo YD-011, YD-013, YD-127, and YD-128 manufactured by Nippon Steel Chemical & Material Co., Ltd., and D.E.R. 317, D.E.R. 331, D.E.R. 661, and D.E.R. manufactured by The Dow Chemical Company. 664, bisphenol A type epoxy resins such as Sumi-Epoxy ESA-011, ESA-014, ELA-115, ELA-128 (all trade names) manufactured by Sumitomo Chemical Co., Ltd.; jERYL903 manufactured by Mitsubishi Chemical Corporation, EPICLON 152, 165 manufactured by DIC Corporation, Epotohto YDB-400, YDB-500 manufactured by Nippon Steel Chemical & Material Co., Ltd., D.E.R. 542 manufactured by Dow Chemical Co., Ltd., Sumi-Epoxy ESB-400, ESB-700 (all trade names) and other brominated epoxy resins; jER152, jER154 manufactured by Mitsubishi Chemical Corporation, D.E.N. 431, D.E.N. 542 manufactured by Dow Chemical Co., Ltd., and other brominated epoxy resins; 438, EPICLON N-730, N-770, N-865 manufactured by DIC, EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, NC-3000 manufactured by Nippon Kayaku Co., Ltd., Sumi-Epoxy ESCN-195X, ESCN-220 manufactured by Sumitomo Chemical Co., Ltd., YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-701, YDCN-704, YDCN-704A manufactured by Nippon Steel Chemical & Material Co., Ltd., EPICLON manufactured by DIC Novolac type epoxy resins such as N-680, N-690, and N-695 (all trade names); bisphenol F type epoxy resins such as EPICLON 830 manufactured by DIC Corporation, jER807 manufactured by Mitsubishi Chemical Corporation, and Epotohto YDF-170, YDF-175, and YDF-2004 manufactured by Nippon Steel Chemical & Material Co., Ltd. (all trade names); hydrogenated bisphenol A type epoxy resins such as Epotohto ST-2004, ST-2007, and ST-3000 (trade names) manufactured by Nippon Steel Chemical & Material Co., Ltd., and YX8034 manufactured by Mitsubishi Chemical Co., Ltd.; glycidyl esters such as jER604 manufactured by Mitsubishi Chemical Corporation, Epotohto YH-434 manufactured by Nippon Steel Chemical & Material Co., Ltd., and Sumi-Epoxy ELM-120 manufactured by Sumitomo Chemical Co., Ltd. (all trade names); amine-type epoxy resins; hydantoin-type epoxy resins; alicyclic epoxy resins such as Celloxide 2021 (all trade names) manufactured by Daicel Corporation; trihydroxyphenylmethane-type epoxy resins such as YL-933 manufactured by Mitsubishi Chemical Corporation, and EPPN-501 and EPPN-502 (all trade names) manufactured by Nippon Kayaku Co., Ltd.; bixylenol-type or biphenol-type epoxy resins or mixtures thereof such as YL-6056, YX-4000, and YL-6121 (all trade names) manufactured by Mitsubishi Chemical Corporation; EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30 manufactured by ADEKA Corporation, and EPPN-501 (all trade names) manufactured by DIC Corporation. Bisphenol S type epoxy resins such as EXA-1514 (trade name); bisphenol A novolac type epoxy resins such as jER157S (trade name) manufactured by Mitsubishi Chemical Corporation; tetraphenylolethane type epoxy resins such as jERYL-931 (all trade names) manufactured by Mitsubishi Chemical Corporation; heterocyclic epoxy resins such as TEPIC (all trade names) manufactured by Nissan Chemical Industries, Ltd.; diglycidyl phthalate resins such as BLEMMER DGT manufactured by NOF Corporation; tetraglycidyl xylenoylethane resins such as ZX-1063 manufactured by Nippon Steel Chemical & Material Co., Ltd.; ESN-190, ESN Epoxy resins containing naphthalene groups, such as HP-360, HP-4032, EXA-4750, and EXA-4700 manufactured by DIC; epoxy resins having a dicyclopentadiene skeleton, such as HP-7200 and HP-7200H manufactured by DIC; glycidyl methacrylate copolymer epoxy resins, such as CP-50S and CP-50M manufactured by NOF Corporation; further, copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate; and CTBN-modified epoxy resins (e.g., YR-102 and YR-450 manufactured by Nippon Steel Chemical & Material Co., Ltd.), but are not limited to these.

Among these, epoxy resins that do not contain a benzene ring are preferred, and for example, heterocyclic epoxy resins such as TEPIC-S, TEPIC-VL, TEPIC-PAS, TEPIC-UC, etc. (all manufactured by Nissan Chemical Industries, Ltd.) and alicyclic epoxy resins such as CELLOXIDE 2000, CELLOXIDE 2021, CELLOXIDE 2081, etc. (all manufactured by Daicel Corporation) are preferably used as the thermosetting component (B).

The amount of the thermosetting component (B) is determined by the total amount with the alkali-soluble resin (C) described below. That is, the total amount of the thermosetting component (B) and the alkali-soluble resin (C) described below is 5.5% by mass or more and 75% by mass or less, preferably 11% by mass or more and 70% by mass or less, and more preferably 21.5% by mass or more and 58% by mass or less, of the curable composition in terms of solid matter.

By making the total amount of (B) the thermosetting component and (C) the alkali-soluble resin 5.5% by mass or more and 75% by mass or less of the curable resin composition in terms of solid matter, it is possible to obtain a curable resin composition that has good viscosity and excellent applicability while ensuring good coating strength.

[(C) Alkali-soluble resin]
The alkali-soluble resin (C) is a resin that enables the curable resin composition to be dissolved in an alkaline developer, i.e., to be developed in an alkaline solution. The alkali-soluble resin (C) is blended when the curable resin composition of the present invention is to be an alkali-developable type.

(C) As the alkali-soluble resin, it is preferable to use a carboxyl group-containing resin or a phenol resin. In particular, it is more preferable to use a carboxyl group-containing resin from the standpoint of developability.

As the carboxyl group-containing resin, various conventionally known carboxyl group-containing resins that have a carboxyl group in the molecule and further have no ethylenically unsaturated group (non-photosensitive) or have such an ethylenically unsaturated group (photosensitive) can be used, but from the viewpoint of making the curable resin composition photocurable and of developing resistance, it is preferable to use one that has an ethylenically unsaturated group (photosensitive).

The ethylenically unsaturated group is a functional group having an ethylenically unsaturated bond, and examples of such groups include a vinyl group and a (meth)acryloyl group. From the viewpoint of reactivity, the (meth)acryloyl group is preferable. Here, the (meth)acryloyl group is a general term that refers to an acryloyl group and a methacryloyl group.

Specific examples of carboxyl group-containing resins that can be used in the curable resin composition of the present invention include the compounds (which may be either oligomers or polymers) listed below.

(1) A carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, or isobutylene.

(2) Carboxyl group-containing urethane resins obtained by polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups.

(3) A urethane resin containing terminal carboxyl groups, which is obtained by reacting an acid anhydride with the terminal of a urethane resin obtained by polyaddition reaction of a diisocyanate compound such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate, or an aromatic diisocyanate with a diol compound such as a polycarbonate polyol, a polyether polyol, a polyester polyol, a polyolefin polyol, an acrylic polyol, a bisphenol A alkylene oxide adduct diol, or a compound having a phenolic hydroxyl group or an alcoholic hydroxyl group.

(4) Photosensitive carboxyl group-containing urethane resins obtained by polyaddition reaction of diisocyanates with (meth)acrylates of bifunctional epoxy resins such as bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bixylenol type epoxy resins, and biphenol type epoxy resins, or their partial acid anhydride modifications, carboxyl group-containing dialcohol compounds, and diol compounds.

(5) A carboxyl group-containing urethane resin that is (meth)acrylated at the terminal by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, during the synthesis of the resin (2) or (4) above.

(6) A carboxyl group-containing urethane resin that is (meth)acrylated at the terminal by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reactant of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin (2) or (4) above.

(7) A photosensitive carboxyl group-containing resin obtained by reacting a multifunctional 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.

(8) A photosensitive carboxyl group-containing resin obtained by reacting a polyfunctional epoxy resin in which the hydroxyl groups of a bifunctional epoxy resin have been further epoxidized with epichlorohydrin with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups.

(9) A carboxyl group-containing polyester resin obtained by reacting a polyfunctional oxetane resin as described below with a dicarboxylic acid and adding a dibasic acid anhydride to the resulting primary hydroxyl groups.

(10) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the reaction product obtained with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

(11) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the reaction product obtained with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

(12) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl group of the resulting reaction product with a polybasic acid anhydride, such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid.

(13) A photosensitive carboxyl group-containing resin 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, α-methylglycidyl (meth)acrylate, etc., to any of the resins (1) to (12) above.

Since the above-mentioned carboxyl group-containing resins have many carboxyl groups on the side chains of the backbone polymer, they can be developed with a dilute alkaline aqueous solution.

Furthermore, it is preferable that (C) the alkali-soluble resin contains a carboxyl group-containing fluororesin.

As the carboxyl group-containing fluororesin, a known fluororesin containing a carboxyl group can be used. A fluororesin is a polymer or oligomer having at least one fluorine atom. The presence of fluorine atoms in the alkali-soluble resin can improve resistance to thermal discoloration.

Specific examples of carboxyl group-containing fluororesins that can be used in the curable resin composition of the present invention include the compounds (which may be either oligomers or polymers) listed below. Note that the "fluorine-substituted compound" described below refers to a compound in which one or more hydrogen atoms other than the hydrogen atoms that constitute the functional groups of a specific compound are substituted with fluorine.

(1) A carboxyl group-containing fluororesin obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with a fluorine-substituted compound containing an unsaturated group such as styrene, α-methylstyrene, alkyl (meth)acrylate (wherein the alkyl has, for example, 2 to 15 carbon atoms, preferably 2 to 8 carbon atoms), or isobutylene.

(2) A carboxyl group-containing urethane resin obtained by polyaddition reaction of a diisocyanate such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate, or an aromatic diisocyanate with a carboxyl group-containing dialcohol compound such as dimethylolpropionic acid or dimethylolbutanoic acid, and a diol compound such as a polycarbonate polyol, a polyether polyol, a polyester polyol, a polyolefin polyol, an acrylic polyol, a bisphenol A alkylene oxide adduct diol, or a compound having a phenolic hydroxyl group or an alcoholic hydroxyl group, in which at least one of the raw materials described is a fluorine-substituted product, and which contains a carboxyl group and a urethane bond.

(3) A urethane resin containing terminal carboxyl groups, which is obtained by reacting an acid anhydride with the terminal of a urethane resin obtained by polyaddition reaction of a diisocyanate compound such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate, or an aromatic diisocyanate with a diol compound such as a polycarbonate polyol, a polyether polyol, a polyester polyol, a polyolefin polyol, an acrylic polyol, a bisphenol A alkylene oxide adduct diol, or a compound having a phenolic hydroxyl group or an alcoholic hydroxyl group, and at least one of the raw materials described is a fluorine-substituted product, and which contains a carboxyl group and a urethane bond.

(4) A photosensitive carboxyl group-containing urethane resin obtained by polyaddition reaction of diisocyanate with (meth)acrylate or its partial acid anhydride modified product of bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin, etc., a carboxyl group-containing dialcohol compound, and a diol compound, in which at least one of the described raw materials is a fluorine-substituted product, and which contains a carboxyl group and a urethane bond.

(5) A fluororesin containing terminal (meth)acrylated carboxyl groups and urethane bonds, which is produced by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, during the synthesis of the resin (2) or (4) above.

(6) A fluororesin containing terminal (meth)acrylated carboxyl groups and urethane bonds, which is produced by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reactant of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin (2) or (4) above.

(7) A photosensitive carboxyl group-containing fluororesin obtained by reacting a fluorine-substituted polyfunctional 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.

(8) A photosensitive carboxyl group-containing fluororesin obtained by reacting a fluorine-substituted polyfunctional epoxy resin, in which the hydroxyl groups of a bifunctional epoxy resin have been further epoxidized with epichlorohydrin, with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups.

(9) A fluororesin containing carboxyl groups and ester bonds, which is obtained by reacting a fluorine-substituted polyfunctional oxetane resin as described below with a dicarboxylic acid and adding a dibasic acid anhydride to the resulting primary hydroxyl groups.

(10) A carboxyl group-containing photosensitive fluororesin obtained by reacting a fluorine-substituted compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the reaction product obtained with an unsaturated group-containing monocarboxylic acid, and reacting the resulting reaction product with a polybasic acid anhydride.

(11) A carboxyl group-containing photosensitive fluororesin obtained by reacting a fluorine-substituted compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the reaction product obtained with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

(12) A carboxyl group-containing photosensitive fluororesin obtained by reacting a fluorine-substituted epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl group of the resulting reaction product with a polybasic acid anhydride, such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid.

(13) A photosensitive carboxyl group-containing fluororesin 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, α-methylglycidyl (meth)acrylate, etc., to any of the resins (1) to (12) above.

The above-mentioned fluorine-substituted compounds can be obtained by fluorinating a given compound. The fluorination method may be a known method, such as low-temperature fluorination, catalytic fluorination, aqueous solution fluorination, liquid-phase fluorination, solid-phase fluorination, or gas-phase fluorination.

When using a carboxyl group-containing fluororesin as the alkali-soluble resin (C), commercially available products that can be used include, for example, carboxyl group-containing fluororesins manufactured by Shin-Nakamura Chemical Co., Ltd. (product names: TIF-1, TIF-2, TIF-3).

The acid value of the alkali-soluble resin (C) is preferably in the range of 20 to 200 mgKOH/g, more preferably in the range of 40 to 150 mgKOH/g. When the acid value of the alkali-soluble resin (C) is 20 mgKOH/g or more, the adhesion of the coating film is good and the alkaline development is good. On the other hand, when the acid value is 200 mgKOH/g or less, dissolution of the exposed area by the developer can be suppressed, so that the lines are prevented from becoming thinner than necessary, and in some cases, the exposed and unexposed areas are prevented from being dissolved and peeled off by the developer without distinction, and a resist pattern can be drawn well.

The weight-average molecular weight of the alkali-soluble resin (C) used in the present invention varies depending on the resin skeleton, but is preferably in the range of 2,000 to 150,000, and more preferably 5,000 to 100,000. When the weight-average molecular weight is 2,000 or more, the tack-free performance is good, the moisture resistance of the coating film after exposure is good, and film loss during development is suppressed, and a decrease in resolution can be suppressed. On the other hand, when the weight-average molecular weight is 150,000 or less, the developability is good and the storage stability is also excellent.

When the curable resin composition of the present invention contains an alkali-soluble resin (C), the amount of the resin in the curable resin composition is, in terms of solid matter, preferably 5% by mass to 60% by mass, more preferably 10% by mass to 60% by mass, even more preferably 15% by mass to 60% by mass, and particularly preferably 20% by mass to 50% by mass. When the amount is 5% by mass to 60% by mass, the coating strength is good, the viscosity of the composition is appropriate, and the coatability and the like are improved.

[(D) Photopolymerization initiator]

When the curable resin composition of the present invention is an alkali development type, a photopolymerization initiator (D) is blended into the curable resin composition to enable photocuring of the composition in the exposure step. As the photopolymerization initiator (D), any of those known as photopolymerization initiators or photoradical generators can be used.

(D) Examples of photopolymerization initiators include 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, and bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide. phosphine oxide, bisacylphosphine oxides such as bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; monoacylphosphine oxides such as 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphine acid isopropyl ester, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 1-hydroxy-cyclohexylphenylphosphine oxide, hydroxyacetophenones such as 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoins such as benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ethers; benzophenone, p-methyl ether, benzophenones such as benzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 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-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4- (4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone and other acetophenones; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone and other thioxanthones; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone and other anthraquinones; acetophenone dimethyl ketal, benzyl dimethyl ketal and other ketals; ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, p-dimethyl Benzoic acid esters such as ethyl benzoate ester; oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime); 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-(1-pyr-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. Among these, monoacylphosphine oxides and oxime esters are preferred, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime) are more preferred. (D) The photopolymerization initiator may be used alone or in combination of two or more.

The amount of (D) photopolymerization initiator is preferably 0.01 to 30 parts by mass, more preferably 0.01 to 20 parts by mass, per 100 parts by mass of (C) alkali-soluble resin. When the amount of (D) photopolymerization initiator is 0.01 parts by mass or more, the photocuring properties are good, the coating film is less likely to peel off, and the coating film properties are good. When the amount of (D) photopolymerization initiator is 30 parts by mass or less, the light absorption of (D) photopolymerization initiator is good, and the deep curing properties are improved.

[Compound having an ethylenically unsaturated group]
The curable resin composition of the present invention may contain a known and commonly used photopolymerizable monomer as a compound having an ethylenically unsaturated group. The compound having an ethylenically unsaturated group is a compound having one or more ethylenically unsaturated groups in the molecule, and assists the photocuring of the alkali-soluble resin by irradiation with active energy rays, thereby curing the curable resin composition.

Examples of compounds used as the compound having an ethylenically unsaturated group include commonly known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, and epoxy (meth)acrylates. Specific examples include hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; acrylamides such as N,N-dimethylacrylamide, N-methylolacrylamide, and N,N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tris-hydroxyethyl isocyanurate, or ethylene oxide adducts, propylene oxide adducts, or ε-caproic acid. Polyhydric acrylates such as lactone adducts; polyhydric acrylates such as phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide adducts of these phenols; polyhydric acrylates of glycidyl ethers such as glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; and, without being limited to the above, acrylates and melamine acrylates obtained by directly acridating polyols such as polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadienes, and polyester polyols, or by urethane acrylate via diisocyanates, and at least one of the methacrylates corresponding to the above acrylates.

In particular, it is preferable that the compound having an ethylenically unsaturated group is a monomer that does not contain a benzene ring. Also, from the viewpoint of improving the strength of the cured product after photocuring, it is preferable that the compound having an ethylenically unsaturated group contains a cyclic compound (but does not contain a benzene ring).

Commercially available compounds having an ethylenically unsaturated group that is a cyclic compound (but does not contain a benzene ring) include A-DCP, A-9300, A-9300YN, A-9300-1CL, DCP (all manufactured by Shin-Nakamura Chemical Co., Ltd.), A1208, D3380, M0594, T2325 (all manufactured by Tokyo Chemical Industry Co., Ltd.), M-215, M-313, M-315 (all manufactured by Toagosei Co., Ltd.), Photomer 4356 (all manufactured by IGM Resins), and FA-731A (all manufactured by Hitachi Chemical Co., Ltd.).

Furthermore, it is preferable that the compound having an ethylenically unsaturated group is a compound having two or more ethylenically unsaturated groups in the molecule.

When a compound having an ethylenically unsaturated group is blended, the blending amount is, in terms of solid content, 10 parts by mass or more and 60 parts by mass or less, preferably 15 parts by mass or more and 50 parts by mass or less, and more preferably 20 parts by mass or more and 40 parts by mass or less, per 100 parts by mass of the total alkali-soluble resin (C).

When the blending amount of the compound having an ethylenically unsaturated group (C) is within the range of 10 parts by mass or more and 60 parts by mass or less in terms of solid content per 100 parts by mass of the total of the alkali-soluble resins (C), the curable resin composition has excellent photocurability, good patterning during development, and good tackiness (dryness to the touch).

[White colorant]
When the curable resin composition of the present invention is used for producing an insulating layer having a high reflectance, it is preferable that a white colorant is blended in the curable resin composition.

White colorants include titanium oxide, zinc oxide, potassium titanate, zirconium oxide, antimony oxide, white lead, zinc sulfide, lead titanate, etc., but titanium oxide is preferably used because it has a high effect of suppressing discoloration due to heat. By including a white colorant, the composition of the present invention can be made white, making it possible to obtain a high reflectance.

The titanium oxide may be any of rutile, anatase, and ramsdellite structures, and may be used alone or in combination of two or more _. Among these, ramsdellite titanium oxide can be obtained by subjecting ramsdellite _Li0.5TiO2 to lithium desorption treatment by chemical oxidation.

Among the above, the use of rutile-type titanium oxide is preferable because it can further improve heat resistance, is less likely to cause discoloration due to light irradiation, and can prevent quality deterioration even under harsh usage environments. In particular, the use of rutile-type titanium oxide surface-treated with aluminum oxide such as alumina or silica can suppress deterioration due to light and further improve reflectance and heat resistance. In addition, another surface treatment can be performed after the above surface treatment. In particular, the reflectance can be further improved by further surface treating with zirconia after surface treating with alumina. When titanium oxide is used as a white colorant, the content of rutile-type titanium oxide surface-treated with aluminum oxide in the total titanium oxide is preferably 10% by mass or more, more preferably 30% by mass or more, with the upper limit being 100% by mass or less, that is, the total amount of titanium oxide may be rutile-type titanium oxide surface-treated with the above aluminum oxide. Examples of rutile-type titanium oxide surface-treated with aluminum oxide include CR-58, a rutile-type chlorine-process titanium oxide manufactured by Ishihara Sangyo Kaisha, Ltd., and R-630, a rutile-type sulfuric acid-process titanium oxide manufactured by the same company. It is also preferable to use rutile-type titanium oxide surface-treated with silicon oxide, and in this case, too, the heat resistance can be further improved. It is also preferable to use rutile-type titanium oxide surface-treated with both aluminum oxide and silicon oxide, and examples of such rutile-type chlorine-process titanium oxide manufactured by Ishihara Sangyo Kaisha, Ltd. include CR-90, a rutile-type chlorine-process titanium oxide manufactured by Ishihara Sangyo Kaisha, Ltd.

In addition, titanium oxide may contain sulfur, but the amount of sulfur is preferably 100 ppm or less, and more preferably 60 ppm or less. If the amount of sulfur is 100 ppm or less, discoloration of the surrounding area due to the sulfur gas generated will not occur.

The amount of such a white colorant is preferably in the range of 5 to 80% by mass, and more preferably in the range of 10 to 70% by mass, based on the solid content in the curable resin composition (components excluding the organic solvent, if the resin composition contains an organic solvent).

[Silica powder]
The curable resin composition of the present invention may contain silica powder in order to impart thixotropy, if necessary. Thixotropy refers to a phenomenon in which the apparent viscosity of a fluid such as a paint reversibly changes when the fluid flows and is allowed to stand.

The silica powder used in the present invention can be either natural or synthetic silica, but synthetic silica, which has stable quality, is generally used.

The silica powder used in the present invention may be ground synthetic or natural crystalline silica, ground fused silica, or spherical fused silica, or synthetic spherical silica, or synthetic fine silica.

Synthetic silica, i.e., hydrous amorphous silicon dioxide ( _SiO2.nH2O ), is produced by reacting _a sodium silicate solution (water glass) with sulfuric acid in a reaction tank, and the shape and particle size can be controlled according to the reaction conditions to produce synthetic spherical silica or synthetic fine powder silica.

Examples of silica powders that are preferably used in the present invention include Aerosil 90, Aerosil 130, Aerosil 150, Aerosil 200, Aerosil 225, Aerosil 300, Aerosil 380, Aerosil OX50, Aerosil TT6600, Aerosil R104, Aerosil R106, Aerosil R202, Aerosil R711, Aerosil R805, Aerosil R812, Aerosil R816, Aerosil R972, Aerosil R974, Aerosil R7200, Aerosil R8200, Aerosil R9200 (all manufactured by Nippon Aerosil Co., Ltd.), ACEMATT 82, ACEMATT HK125, ACEMATT HK400, ACEMATT HK460, ACEMATT TS100, ACEMATT 82 (all manufactured by EVONIK synthetic fine silica such as E-200A, E-220A, K-500, E-1009, E-1011, E-1030, E-150J, E-170, E-200, E-220, E-743, E-75, HD, HD-2, L-250, L-300, G-300, SS-10, SS-50, SS-30P, SS-30V, SS-30X, SS-50, and SS-70 (all manufactured by Tosoh Silica Corporation); FUSELEX RD-8, FUSELEX RD-8AL, FUSELEX RD-120, FUSELEX MCF-200C, FUSELEX Fused ground silica such as GP-200TC, FUSELEX TZ-20, FUSELEX ZA-30C, FUSELEX E-1, FUSELEX E-2, FUSELEX AS-1, FUSELEX X (all manufactured by Tatsumori Co., Ltd.), FS-3DC, FS-5DC (all manufactured by Denka Co., Ltd.), FB-5D, FB-12D, FB-20D, FB-105, FB-940, FB-9454, FB-950, FB-105FC, FB-870FC, FB-875FC, FB-9454FC, FB-950FC, FB-300FC, FB-105 FD, FB-970FD, FB-975FD, FB-950FD, FB-300FD, FB-400FD, FB-7SDC, FB-5SDC, FB-3SDC, FB-74X, FB-25SX, FB-35X, FB-302X, FB-105X, FB-940X, FB- 950X, FB-105XFC, FB-950XFC, FB-100XF D, FB-950XFD, FB-7SDX, FB-5SDX, FB-3SDX (manufactured by Denka), MSR-2212, MSR-25, MSR-3512, MSR-2214M4, MSV-2212N, MSV-2212NH, MSV-2507NH, MSV-3512N , MSV-3512NH, MSS-7, MSS-6, EXR-4, E Fused spherical silica such as XR-3, AC-5VLD, B-21, A-21, MP-15EF, AC-5V, and MP-8FS (all manufactured by Tatsumori Co., Ltd.); synthetic spherical silica such as SO-E1, SO-E2, SO-E3, SO-E5, SO-E6, SO-C1, SO-C2, SO-C3, SO-C5, and SO-C6 (all manufactured by Admatechs Co., Ltd.); CRYSTALITE Examples of crystalline crushed silica include CRYSTALITE 3K, CRYSTALITE 3K-S, CRYSTALITE C, CRYSTALITE TNC-1, CRYSTALITE NX-7, CRYSTALITE SMT-10, CRYSTALITE CMC-12S, CRYSTALITE XJ-7, CRYSTALITE C-BASE-1, CRYSTALITE A-1, CRYSTALITE A-A, and CRYSTALITE VX-S2 (all manufactured by Tatsumori Co., Ltd.).

When silica powder is added, synthetic fine silica is preferably used from the viewpoint of dispersibility, but a mixture of synthetic fine silica and fused pulverized silica may also be used.

The amount of silica powder is preferably 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and particularly preferably 0.5 to 5 parts by mass, relative to 100 parts by mass (solid content) of the curable resin composition. This range ensures that the silica powder exerts its effect as a thixotropic agent, i.e., inhibits the settling and separation of components (such as whitening agent powder) in the curable resin composition, reduces the viscosity when applied to a substrate, and improves leveling after application.

[Other ingredients]
The curable resin composition of the present invention may contain a defoaming agent. Examples of defoaming agents include silicon-based defoaming agents and non-silicon-based defoaming agents. Among them, it is preferable to use a non-silicon-based defoaming agent from the viewpoint of reducing contamination of the developer and preventing poor adhesion of the marking ink. One type of defoaming agent may be used, or two or more types may be used in combination.

Examples of silicone-based defoamers include KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of non-silicone-based defoamers include FOAMKILLER NSI-0.00 (manufactured by Aoki Oil Industries Co., Ltd.).

The amount of the defoamer, calculated as solid content, is preferably 0.01 to 30.00 parts by mass per 100 parts by mass of the alkali-soluble resin (C).

The yellowing of the cured product of the curable resin composition is not limited to white curable resin compositions, but can also be a problem in transparent, semi-transparent, or cured films to which a small amount of colorant has been added. Therefore, the curable resin composition of the present invention may contain a colorant other than a white colorant. Specific examples of colorants include phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, leuco crystal violet, carbon black, naphthalene black, and solvent blue. The colorants may be used alone or in combination of two or more.

In addition, the curable resin composition of the present invention may contain an organic solvent for purposes such as preparing the composition or adjusting the viscosity when applying it to a substrate or carrier film. Examples of the organic solvent 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 monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. Known and commonly used organic solvents can be used. These organic solvents can be used alone or in combination of two or more.

The curable resin composition of the present invention may further contain other additives that are well known and commonly used in the field of electronic materials. Examples of other additives include thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, antiaging agents, antibacterial and antifungal agents, leveling agents, thickeners, adhesion imparting agents, thixotropy imparting agents (excluding silica powder), photoinitiator assistants, sensitizers, photobase generators, organic fillers such as thermoplastic resins, elastomers, and urethane beads, inorganic fillers such as barium sulfate, talc, and silica (excluding silica powder), release agents, surface treatment agents, dispersants, dispersion assistants, surface modifiers, stabilizers, fluorescent materials, and cellulose resins.

The curable resin composition of the present invention may be used in the form of a dry film or in liquid form. When used in liquid form, it may be a one-component or two or more-component composition.

<Dry film>
The dry film of the present invention has a resin layer obtained by applying and drying the curable resin composition of the present invention on a carrier film. When forming a dry film, first, the curable resin composition of the present invention is diluted with the organic solvent to adjust the viscosity to an appropriate level, and then coated on the carrier film to a uniform thickness using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. Thereafter, the applied composition is usually dried at a temperature of 50 to 130° C. for 1 to 30 minutes to form a resin layer. There is no particular restriction on the coating thickness, but it is generally appropriately selected within the range of 10 to 150 μm, preferably 20 to 60 μm, in terms of the film thickness after drying.

As the carrier film, a plastic film is used, for example, a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, a polystyrene film, etc. can be used. There is no particular restriction on the thickness of the carrier film, but it is generally selected appropriately in the range of 10 to 150 μm.

After forming a resin layer made of the curable resin composition of the present invention on the carrier film, it is preferable to further laminate a peelable cover film on the surface of the film for the purpose of preventing dust from adhering to the surface of the film. As the peelable cover film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, etc. can be used. The cover film may have a smaller adhesive force than that between the resin layer and the carrier film when the cover film is peeled off.

In the present invention, the curable 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, when producing a dry film in the present invention, either a carrier film or a cover film may be used as the film to which the curable resin composition of the present invention is applied.

<Cured Product>
First, the case where the curable resin composition of the present invention is an alkali-developable type (that is, containing an alkali-soluble resin (C) and a photopolymerization initiator (D)) will be described.

In this case, to form a cured product using the curable resin composition of the present invention, the composition is applied to a substrate, the solvent is evaporated and dried, and the resulting resin layer is exposed (irradiated with light) to cure the exposed areas (areas irradiated with light). Specifically, the composition is selectively exposed to active energy rays through a photomask with a pattern formed thereon, using a contact or non-contact method, or directly exposed to a pattern using a laser direct exposure machine, and the unexposed areas are developed with an alkaline aqueous solution (e.g., a 0.3 to 3% by weight aqueous solution of sodium carbonate), to form a pattern of the cured product. The composition is then heated to a temperature of about 100 to 180°C for thermal curing (post-cure), to form a cured film (cured product) with excellent properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties.

When the curable resin composition of the present invention is not of the alkali-developable type, the curable resin composition is, for example, of the heat-curable type that does not contain (C) an alkali-soluble resin and (D) a photopolymerization initiator. In this case, to form a cured product, the composition is applied onto a substrate, and the solvent is evaporated and dried to obtain a resin layer, which is then heated to a temperature of about 100 to 180°C for thermal curing to obtain a cured coating (cured product).

The curable resin composition of the present invention can be adjusted to a viscosity suitable for the coating method using the organic solvent, and applied to a substrate by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating, and then the organic solvent contained in the composition can be evaporated and dried (pre-dried) at a temperature of about 60 to 100°C to form a tack-free resin layer. In addition, in the case of a dry film in which the composition is applied to a carrier film or cover film, dried, and wound up as a film, a resin layer can be formed on the substrate by laminating the composition of the present invention to the substrate using a laminator or the like so that the layer of the composition is in contact with the substrate, and then peeling off the carrier film.

The above-mentioned substrates include printed wiring boards and flexible printed wiring boards with circuits formed in advance using copper or the like, as well as materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth/non-woven cloth epoxy, glass cloth/paper epoxy, synthetic fiber epoxy, copper-clad laminates for high-frequency circuits using fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc., and include 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 volatilization drying or thermal curing can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method in which hot air in the dryer is brought into countercurrent contact using a heat source that uses steam for air heating, or a method in which hot air is blown onto the support from a nozzle).

The exposure machine used for the above-mentioned active energy ray irradiation may be a machine equipped with a high pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, and capable of irradiating active energy rays in the range of 350 to 450 nm, and further, a direct imaging machine (for example, a laser direct imaging machine that draws an image directly with a laser based on CAD data from a computer) may also be used. The lamp light source or laser light source of the direct imaging machine may have a maximum wavelength in the range of 350 to 410 nm. The exposure dose for image formation varies depending on the film thickness, etc., but can generally be within the range of 20 to 1000 mJ/cm ² , preferably 20 to 800 mJ/cm ² .

The above-mentioned developing method can be a dipping method, a shower method, a spray method, a brush method, etc., and the developing solution can be an alkaline aqueous solution of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc.

The curable resin composition of the present invention is suitable for use in forming solder resists and coverlays, and is particularly suitable for use in forming solder resists.

<Electronic Components>
The present invention also provides an electronic component having a cured product obtained by curing the resin layer of the curable resin composition or dry film of the present invention. By using the cured product of the curable resin composition of the present invention, an electronic component having high appearance, durability, and productivity is provided. In the present invention, the electronic component means a component used in an electronic circuit, and includes active components such as printed wiring boards, transistors, light-emitting diodes, and laser diodes, as well as passive components such as resistors, capacitors, inductors, and connectors, and the cured product of the curable resin composition of the present invention exerts the effects of the present invention as an insulating cured coating film for these components.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

1. Preparation of curable resin compositions of Examples 1 to 7 and Comparative Examples 1 to 5
Various components shown in the Examples and Comparative Examples in Table 1 below were premixed in a stirrer in the ratios (parts by mass) shown in Table 1, and then kneaded in a three-roll mill to prepare curable resin compositions. The values in the table indicate parts by mass (non-volatile content, i.e., solid content).

Test samples were prepared for each of the curable resin compositions as shown below, and evaluations were performed on the developability, reflectance (initial value), b* value (initial value), reflectance (after UV irradiation), UV treatment ΔE (photodiscoloration resistance), and 250 μm opening. The results are shown in Table 1.

<Synthesis Example 1 of Component (C-2)>
A 2-liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube was charged with 900 g of diethylene glycol dimethyl ether as a solvent and 21.4 g of t-butylperoxy-2-ethylhexanoate (Perbutyl O, manufactured by Nippon Oil & Fats Co., Ltd.) as a polymerization initiator, and heated to 90° C. After heating, 309.9 g of methacrylic acid, 116.4 g of methyl methacrylate, and 109.8 g of lactone-modified 2-hydroxyethyl methacrylate (Placcel FM1, manufactured by Daicel Chemical Industries, Ltd.) were added dropwise over 3 hours together with 21.4 g of bis(4-t-butylcyclohexyl)peroxydicarbonate (Perloyl TCP, manufactured by Nippon Oil & Fats Co., Ltd.) as a polymerization initiator, and the mixture was further aged for 6 hours to obtain a carboxyl group-containing copolymer resin. The reaction was carried out under a nitrogen atmosphere.

Next, 363.9 g of 3,4-epoxycyclohexylmethyl acrylate (Cyclomer A200, Daicel Chemical Industries, Ltd.), 3.6 g of dimethylbenzylamine as a ring-opening catalyst, and 1.80 g of hydroquinone monomethyl ether as a polymerization inhibitor were added to the obtained carboxyl group-containing copolymer resin, and the mixture was heated to 100°C and stirred to carry out a ring-opening addition reaction of the epoxy. After 16 hours, a solution containing a carboxyl group-containing resin (alkali-soluble resin (C)) without aromatic rings, with a solid acid value of 108.9 mgKOH/g and a weight average molecular weight of 25,000, was obtained.

<Evaluation method>
(1) Developability Each of the curable resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 was applied using an applicator to a copper-clad laminate of FR-4 1.6 mm thick and 18 μm thick copper foil that had been buffed (two rows of Scotch brite SF (equivalent to #600) and UEF (equivalent to #1000)), and dried at 80° C. for 30 minutes to obtain a dried coating film with a film thickness of 20 μm. The resulting product was then immersed in a 1 wt % aqueous sodium carbonate solution, and the developability was evaluated according to the following criteria.

Note that since Example 7 does not contain an alkali-soluble resin, developability was not evaluated.

○: Development time is 90 seconds or more and less than 120 seconds ×: Development time is 120 seconds or more -: Not rated

(2) Reflectance (initial value)
Each of the curable resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 was applied to a copper-clad laminate of 1.6 mm thick copper foil 18 μm thick buffed (two strips of Scotch brite SF (equivalent to #600) and UEF (equivalent to #1000)) using an applicator, and dried at 80°C for 30 minutes to obtain a dried coating film with a thickness of 20 μm. Thereafter, the substrate was irradiated with active energy rays at an exposure dose of 600 mJ/ ^cm2 using a metal halide lamp light source through a negative mask having patterning, and then immersed in a 1 wt% aqueous sodium carbonate solution. Thereafter, a thermal curing treatment was performed at 150°C for 1 hour to obtain a substrate having a cured coating film.

The curable resin composition of Example 7 was applied to a substrate using an applicator, dried at 80°C for 30 minutes, and then thermally cured at 150°C for 1 hour to obtain a substrate having a cured coating film. In other words, the curable resin composition of Example 7 was not subjected to alkaline development.

For each substrate having these cured coatings, a color difference meter (CR-400, manufactured by Konica Minolta) was used to measure the reflectance at a wavelength of 450 nm using the SCI (specularly reflected light included) method, which evaluates the color of the material itself regardless of the surface condition because the measurement includes specular reflected light. Here, the initial value refers to the initial value (before UV irradiation) compared with the values after UV irradiation of (4) reflectance (after UV irradiation) and (5) UV treatment ΔE (resistance to photodiscoloration), which will be described later. The same applies to the initial value of (3) b* value, which will be described later. The evaluation criteria for reflectance (initial value) are as follows:

○: 89% or more ×: Less than 89%

(3) b* value (initial value)
The same substrate as that used in the evaluation of (2) reflectance (initial value) was measured by the SCI method using a spectrophotometer (CM-2600d, manufactured by Konica Minolta) and the CIE L*a*b* color system (standard light source D65 was used). The evaluation criteria for the b* value (initial value) are as follows.

○: 1 or less ×: 2 or more

(4) Reflectance (after UV irradiation)
The same substrate as that used in the evaluation of reflectance (initial value) above (2) was prepared, and the surface of the cured coating film formed on the substrate was irradiated with UV light at 20 J/ ^cm2 using a metal halide lamp as a light source. The reflectance of the substrate after UV light irradiation was measured in the same manner as in (2) Reflectance (initial value) above, except that the wavelength was changed to 451 nm. The evaluation criteria for reflectance (after UV irradiation) were as follows: That is correct.

○: 85% or more ×: Less than 85%

(5) UV treatment ΔE (resistance to photodiscoloration)
The change in color ΔE (ΔE*ab, color difference) from the initial value was calculated for the substrate before and after UV irradiation in the above (4) reflectance (after UV irradiation). The standard for change in UV treatment ΔE (resistance to photodiscoloration) is as follows:

○: 0.9 or less ×: 1.0 or more

(6) 250 μm opening property Each of the curable resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 was applied to a copper-clad laminate having a thickness of 1.6 mm and a thickness of 18 μm, which was buffed (two rows of Scotch brite SF (equivalent to #600) and UEF (equivalent to #1000)), using an applicator, and dried at 80 ° C. for 30 minutes to obtain a dry coating film having a thickness of 20 μm. Thereafter, the film was irradiated with active energy rays at an exposure dose of 600 mJ using a metal halide lamp light source through a negative having a pattern in which a plurality of openings of 250 μm x 250 μm were formed, and then the film was immersed in a 1 wt % aqueous sodium carbonate solution for development, and then heated at 150 ° C. for 60 minutes to perform a curing treatment. Note that the curable resin composition of Example 7 cannot be developed with an alkali, so this evaluation was not performed. The evaluation criteria for the opening property of 250 μm are as follows.

◯: An opening of 180 μm or more and less than 210 μm could be formed. ×: An opening of less than 180 μm was formed. -: Not evaluated.

*1: Pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (vapor pressure: 1.3 x 10E-10 Pa (20 ° C.)) (Irganox 1010: manufactured by BASF Japan)
*2: Ethylene bis (oxyethylene) bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl) propionate) (vapor pressure: 4.0 × 10E-8 Pa (20 ° C.)) (Irganox 245: manufactured by BASF Japan)
*3: Hexamethylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (vapor pressure: 1.3×10E-8 Pa (20°C)) (Irganox 259: manufactured by BASF Japan)
*4: 1,3,5-tris[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (vapor pressure: 7.0×10E-13 Pa (20°C)) (Irganox 3114: manufactured by BASF Japan)
*5: 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene (vapor pressure: 2.0 x 10E-11 Pa (20 ° C.)) (Irganox 1330: manufactured by BASF Japan)
*6: Octyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate (vapor pressure: 1.5 x 10E-3 Pa (25 ° C.)) (Irganox 1135: manufactured by BASF Japan)
*7: Isocyanurate type epoxy resin (TEPIC-VL: manufactured by Nissan Chemical Industries, Ltd.)
*8: Alicyclic epoxy resin (Celloxide 2021P: manufactured by Daicel Corporation)
*9: Carboxyl group-containing fluororesin (acid value 130 mg KOH/g) (TIF-3: manufactured by Shin-Nakamura Chemical Co., Ltd.)
*10: Carboxylic group-containing copolymer (photosensitive) resin of Synthesis Example 1
*11: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (Omnirad TPO H: manufactured by IGM Resins)
*12: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819: manufactured by IGM Resins)
*13: Ethoxylated isocyanuric acid triacrylate (A-9300YN: manufactured by Shin-Nakamura Chemical Co., Ltd.)
*14: Aliphatic bifunctional acrylate (A-DOD-N: manufactured by Shin-Nakamura Chemical)
*15: Rutile titanium dioxide (PX-3788: Sakai Chemical Industry Co., Ltd.)
*16: Fine silica (Nipsil (registered trademark) E-743: manufactured by Tosoh Silica Corporation)
*17: Fine silica (AEROSIL (registered trademark) R974: manufactured by Nippon Aerosil Co., Ltd.)

It was found that the curable resin compositions of Examples 1 to 7 were capable of obtaining cured products that could prevent yellowing during thermal curing while suppressing yellowing due to ultraviolet irradiation, as compared with the curable resin compositions of Comparative Examples 1 to 5. In particular, the above effect could not be obtained unless both (A1) a hindered phenol-based antioxidant having an ester skeleton and having a vapor pressure of 1.0×10 ⁻⁷ Pa or less at 20° C. and (A2) a hindered phenol-based antioxidant having an isocyanurate structure were contained.

In addition, it was found that the curable resin compositions of Examples 1 to 6 were able to provide curable resin compositions that exhibited good alkaline developability while exhibiting the above-mentioned effect of suppressing and preventing yellowing during thermal curing and ultraviolet irradiation.

Claims (5)

A curable resin composition comprising: (A) a hindered phenol-based antioxidant; (B) a thermosetting component ; (C) an alkali-soluble resin; and (D) a photopolymerization initiator ,
(A) a hindered phenol-based antioxidant,
(A1) a hindered phenol-based antioxidant having an ester skeleton and a vapor pressure at 20° C. of 1.0×10 ⁻⁷ Pa or less;
(A2) a hindered phenol-based antioxidant having an isocyanurate structure;
A curable resin composition comprising at least The curable resin composition according to claim 1, characterized in that the blending amounts of (A1) the hindered phenol-based antioxidant having an ester skeleton and having a vapor pressure of 1.0 × 10 ^-7 Pa or less at 20°C and (A2) the hindered phenol-based antioxidant having an isocyanurate structure are each 0.1 parts by mass or more and 5.0 parts by mass or less, based on a total of 100 parts by mass of the thermosetting component (B) and the alkali-soluble resin (C), calculated as solid content. A dry film comprising the curable resin composition according to claim 1 or 2 as a resin layer. A cured product obtained by curing the curable resin composition according to claim 1 or 2 , or the resin layer of the dry film according to claim 3 . An electronic part comprising the cured product according to claim 4 .