JP2015206992A - Photosensitive resin composition, dry film, cured product, and printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition giving a cured product on which a friction mark is hardly generated, a dry film obtained by applying and drying the composition, a cured product of the composition or the dry film, and a printed wiring board having the cured product.SOLUTION: The photosensitive resin composition contains (A) a carboxyl group-containing resin, (B) a urethane (meth)acrylate having 6 or more functional groups, (C) a photopolymerization initiator, and (D) titanium oxide. The weight-average molecular weight of the urethane (meth)acrylate (B) having 6 or more functional groups is preferably 1,500-200,000.

Description

  The present invention relates to a photosensitive resin composition, a dry film, a cured product, and a printed wiring board, and more specifically, a photosensitive resin composition that hardly causes friction marks on the cured product, a dry film formed by applying and drying the composition, The present invention relates to a cured product of the composition or the dry film, and a printed wiring board having the cured product.

  It is widely used as an insulating layer such as a solder resist by applying a photosensitive resin composition to a substrate such as a printed wiring board and photocuring it (for example, Patent Document 1). When the photocurable composition is used as an insulating layer of a printed wiring board on which a light emitting element such as a light emitting diode (LED) or electroluminescence (EL) is mounted, it has a high reflectance so that light can be used effectively. It is often configured as a white photosensitive resin composition (for example, Patent Document 2).

JP 2005-31233 A JP 2010-160471 A

  Insulating layers such as solder resist provided on the printed wiring board come into contact with metals such as copper due to stacking of the printed wiring boards or contact between the printed wiring board and the transport roll during the manufacture of printed wiring boards or electronic devices. There is. In the case of a solder resist provided on a flexible wiring board, it may be wound around a metal when a component is mounted in an electronic device. It has been found that when titanium oxide is highly filled in order to obtain a white solder resist with high reflectivity, there is a problem that friction marks are generated on the solder resist due to such contact with metal during production or practical use. .

  Accordingly, an object of the present invention is to provide a photosensitive resin composition that hardly causes friction marks on a cured product, a dry film obtained by applying and drying the composition, a cured product of the composition or the dry film, and the cured product. It is in providing the printed wiring board which has.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by adding a urethane (meth) acrylate having 6 or more functional groups to the photosensitive resin composition. The present invention has been completed.

  That is, the photosensitive resin composition of the present invention comprises (A) a carboxyl group-containing resin, (B) a urethane (meth) acrylate having 6 or more functional groups, (C) a photopolymerization initiator, and (D) an oxidation. It is characterized by containing titanium.

  In the photosensitive resin composition of the present invention, the urethane (meth) acrylate having 6 or more functional groups (B) preferably has a weight average molecular weight of 1,500 to 200,000.

  The photosensitive resin composition of the present invention preferably further contains at least one of a metal hydroxide and a phosphorus compound.

  The dry film of the present invention is characterized in that the photosensitive resin composition is applied to a film and dried.

  The cured product of the present invention is obtained by curing the photosensitive resin composition or the dry film.

  The printed wiring board of this invention has the said hardened | cured material, It is characterized by the above-mentioned.

  According to the present invention, a photosensitive resin composition that is excellent in resolution and bendability of a cured product and hardly causes friction marks on the cured product, a dry film obtained by applying and drying the composition, the composition or the dry film It becomes possible to provide a cured product and a printed wiring board having the cured product.

  The photosensitive resin composition of the present invention comprises (A) a carboxyl group-containing resin, (B) a urethane (meth) acrylate having 6 or more functional groups (hereinafter, also simply referred to as “(B) urethane (meth) acrylate”). , (C) a photopolymerization initiator, and (D) titanium oxide. Friction marks generated in the cured product are considered to be due to the fact that titanium oxide having a high hardness has caused the metal scraped to titanium oxide exposed on the surface of the solder resist due to friction with the metal to adhere to the surface of the solder resist. In the present invention, the blending of (B) urethane (meth) acrylate having 6 or more functional groups improves the surface hardness of the cured product and reduces the exposure of titanium oxide due to friction. Hereinafter, it is also referred to as “excellent scratch resistance”). As another means for improving the surface hardness, it is conceivable to increase the blending amount of the photopolymerization initiator and the photopolymerizable monomer, but these cured products obtained from the photosensitive resin composition of the present invention are This method is also excellent in resolution that can be deteriorated and bendability of the cured product. Further, when titanium oxide is highly filled, the glossiness is lowered, but the cured product obtained from the photosensitive resin composition of the present invention also has a good glossiness. Here, “(meth) acrylate” is a generic term for acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions in the present specification. Hereinafter, each component will be described in detail.

[(A) Carboxyl group-containing resin]
As said (A) carboxyl group containing resin, resin containing a well-known carboxyl group can be used. Due to the presence of the carboxyl group, the resin composition can be made alkali developable. Further, from the viewpoint of making the photosensitive resin composition of the present invention photocurable and developing resistance, it is preferable to have an ethylenically unsaturated bond in the molecule in addition to the carboxyl group. Only a carboxyl group-containing resin having no double bond can be used as the component (A). As the ethylenically unsaturated double bond, those derived from acrylic acid, methacrylic acid or derivatives thereof are preferable. (A) A carboxyl group-containing resin can be used alone or in combination of two or more.

  Specific examples of the carboxyl group-containing resin that can be used in the photosensitive resin composition of the present invention include compounds listed below (any of oligomers and polymers).

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

  (2) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates; carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, and polyethers A carboxyl group-containing urethane resin by a polyaddition reaction of a diol compound such as a polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

  (3) Diisocyanate compounds such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A systems A terminal carboxyl group-containing urethane resin obtained by reacting an acid anhydride with a terminal of a urethane resin by a polyaddition reaction of a diol compound such as an alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

  (4) Diisocyanate and 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 ( Photosensitive carboxyl group-containing urethane resin by polyaddition reaction of (meth) acrylate or its modified partial anhydride, carboxyl group-containing dialcohol compound and diol compound.

  (5) During the synthesis of the resin of the above (2) or (4), a compound having one hydroxyl group and one or more (meth) acryloyl groups in a molecule such as hydroxyalkyl (meth) acrylate is added, and the terminal ( (Meth) acrylic carboxyl group-containing urethane resin.

  (6) During the synthesis of the resin of the above (2) or (4), one isocyanate group and one or more (meth) acryloyl groups are introduced into the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate. The carboxyl group-containing urethane resin which added the compound which has and was terminally (meth) acrylated.

  (7) React (meth) acrylic acid with a polyfunctional epoxy resin as described later, and add a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride to the hydroxyl group present in the side chain. A photosensitive carboxyl group-containing resin. Here, the polyfunctional epoxy resin may be solid or liquid.

  (8) A photosensitive carboxyl group obtained by reacting (meth) acrylic acid with a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl group of a bifunctional epoxy resin with epichlorohydrin and adding a dibasic acid anhydride to the resulting hydroxyl group Containing resin. Here, the bifunctional epoxy resin may be solid or liquid.

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

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

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

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

  (13) One epoxy group and one or more (meth) acryloyl in a molecule such as glycidyl (meth) acrylate, α-methylglycidyl (meth) acrylate and the like in any one of the resins (1) to (12) above A photosensitive carboxyl group-containing resin obtained by adding a compound having a group.

Since the carboxyl group-containing resin as described above has many carboxyl groups in the side chain of the backbone polymer, development with a dilute alkaline aqueous solution becomes possible.
The acid value of the (A) carboxyl group-containing resin 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 carboxyl group-containing resin is 20 mgKOH / g or more, the adhesion of the coating film is good and the alkali development is good. On the other hand, when the acid value is 200 mgKOH / g or less, the dissolution of the exposed part by the developer is suppressed, and the line is thinned more than necessary. The resist pattern can be drawn satisfactorily.

  The weight average molecular weight of the (A) carboxyl group-containing resin varies depending on the resin skeleton, but is preferably in the range of 2,000 to 150,000, 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 coated film after exposure is good, the film loss during development can be suppressed, and the 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. The weight average molecular weight can be measured by gel permeation chromatography.

  Among the carboxyl group-containing resins, the polyfunctional epoxy resin used for the synthesis of the resin is selected from the group consisting of a bisphenol A structure, a bisphenol F structure, a biphenol structure, a bisphenol novolak structure, a bisxylenol structure, and a biphenyl novolak structure. In the case of a polyfunctional epoxy resin having a partial structure or a hydrogenated compound thereof, or a carboxyl group-containing resin having a urethane structure, it is preferable from the viewpoint of low warpage and bending resistance of the obtained cured product.

  Among the carboxyl group-containing resins having a urethane structure, a carboxyl group-containing urethane resin obtained by using a diisocyanate in which an isocyanate group is not directly bonded to a benzene ring is used as a component having an isocyanate group (including a diisocyanate). Since there is no change, it is effective for concealment and has little UV absorption, it is preferable because it has excellent resolution when used as an alkali-developable composition.

  (A) The compounding quantity of carboxyl group-containing resin is 5-60 mass% in the whole composition in conversion of solid content, Preferably it is 10-60 mass%, More preferably, it is 15-50 mass%. . In the case of 5% by mass or more, the coating film strength is good. On the other hand, when the amount is 60% by mass or less, the viscosity of the composition does not become too high, and the coating property and the like become good.

[(B) Urethane (meth) acrylate]
The photosensitive resin composition of the present invention contains (B) urethane (meth) acrylate having 6 or more functional groups. The functional group here means an acryloyl group or a methacryloyl group. The number of functional groups is preferably 6-15. In the case of the above range, both the bendability and the resolution of the coating film can be achieved, and the scratch resistance is excellent.

  (B) The weight average molecular weight of the urethane (meth) acrylate having 6 or more functional groups is preferably 1,500 to 200,000. In the case of the above-mentioned range, both the development resistance of the cured part and the developability of the uncured part can be achieved, and the scratch resistance is more excellent. More preferably, it is 1,500-40,000.

  (B) As urethane (meth) acrylate, Art resin UN-3320HA, UN-3320HABA, UN-3320HB, UN-3320HC, UN-3320HS, UN-3320HS, UN-904, UN-901T, UN-905, UN manufactured by Negami Kogyo Co., Ltd. -952, Daicel Ornex EBECRYL220, 5129, 8301, Daicel Ornex KRM8200, 8200AE, 8452, Sartomer CN968, 975, Shin-Nakamura Chemical U-6LPA, U-10HA, U-10PA, UA-1100H, U-15HA, UA-53H, UA-33H, etc. can be used. (B) Urethane (meth) acrylate can be used individually by 1 type or in combination of 2 or more types.

(B) It is preferable that the compounding quantity of urethane (meth) acrylate is 10-200 mass parts with respect to 100 mass parts of (A) carboxyl group-containing resin. In the above range, the contrast between the development resistance of the cured portion and the developability of the uncured portion can be maintained, and the resolution is excellent. Moreover, it is excellent in glossiness. More preferably, it is 10-150 mass parts. Moreover, the photosensitive resin composition of this invention may contain the compound (photopolymerizable monomer) which has 1 or more ethylenically unsaturated groups in a molecule | numerator other than (B) urethane (meth) acrylate. Good.
(B) It is preferable that urethane (meth) acrylate does not contain a carboxyl group.

[(C) Photopolymerization initiator]
The photosensitive resin composition of the present invention contains (C) a photopolymerization initiator. (C) As a photopolymerization initiator, an oxime ester photopolymerization initiator having an oxime ester group, an alkylphenone photopolymerization initiator, an α-aminoacetophenone photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, One or more photopolymerization initiators selected from the group consisting of titanocene photopolymerization initiators can be suitably used. The oxime ester photopolymerization initiator is preferable because it requires only a small amount of addition and suppresses outgassing, and thus has an effect on PCT resistance and crack resistance.

  Examples of the oxime ester photopolymerization initiator include CGI-325, Irgacure OXE01, Irgacure OXE02 manufactured by BASF Japan, N-1919, NCI-831 manufactured by ADEKA, and the like as commercially available products. Moreover, the photoinitiator which has two oxime ester groups in a molecule | numerator can also be used suitably. As the oxime ester photopolymerization initiator, a compound having a carbazole structure is particularly preferable.

  The blending amount of such an oxime ester photopolymerization initiator is preferably 0.01 to 10 parts by mass, and 0.25 to 5 parts by mass with respect to 100 parts by mass of the (A) carboxyl group-containing resin. More preferably. By setting the content to 0.01 to 10 parts by mass, a cured film having excellent photocurability and resolution, improved adhesion and PCT resistance, and excellent chemical resistance such as electroless gold plating resistance is obtained. be able to. In particular, when the amount is 5 parts by mass or less, it is possible to suppress a decrease in deep part curability due to intense light absorption on the coating film surface.

  Examples of commercially available alkylphenone photopolymerization initiators include α-hydroxyalkylphenone types such as Irgacure 184, Darocur 1173, Irgacure 2959, and Irgacure 127 manufactured by BASF Japan.

  As the α-aminoacetophenone photopolymerization initiator, specifically, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, N , N-dimethylaminoacetophenone and the like. Examples of commercially available products include Irgacure 907, Irgacure 369, and Irgacure 379 manufactured by BASF Japan.

  Specific examples of the acylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and bis (2,6-dimethoxy). And benzoyl) -2,4,4-trimethyl-pentylphosphine oxide. Examples of commercially available products include Lucilin TPO manufactured by BASF, Irgacure 819 manufactured by BASF Japan, and the like.

  The blending amount of these α-aminoacetophenone photopolymerization initiator and acylphosphine oxide photopolymerization initiator is preferably 0.1 to 25 parts by mass with respect to 100 parts by mass of (A) carboxyl group-containing resin. 1 to 20 parts by mass is more preferable. By being 0.1 to 25 parts by mass, a cured film having excellent photocurability and resolution, improved adhesion and PCT resistance, and excellent chemical resistance such as electroless gold plating resistance is obtained. be able to. In particular, when it is 25 parts by mass or less, an effect of reducing outgas can be obtained, and further, it is possible to suppress a decrease in deep part curability due to intense light absorption on the coating film surface.

  Further, Irgacure 389 manufactured by BASF Japan can also be suitably used as a photopolymerization initiator. The suitable compounding quantity of Irgacure 389 is 0.1-20 mass parts with respect to 100 mass parts of said carboxyl group-containing resin, More preferably, it is 1-15 mass parts.

A titanocene photopolymerization initiator such as Irgacure 784 can also be suitably used. The suitable compounding quantity of a titanocene type photoinitiator is 0.01-5 mass parts with respect to 100 mass parts of carboxyl group-containing resin, and a more suitable compounding quantity is 0.01-3 mass parts. .
By setting these photopolymerization initiators in suitable amounts, they are excellent in photocurability and resolution, improved in adhesion and PCT resistance, and also in chemical resistance such as electroless gold plating resistance. Cured product can be obtained. Moreover, in the case of a suitable compounding amount, an effect of reducing outgas is obtained, and further, a decrease in deep curability due to intense light absorption on the surface of the coating film can be suppressed.

  The photosensitive resin composition can use a photoinitiator and a sensitizer in addition to the photopolymerization initiator. Photoinitiators, photoinitiators, and sensitizers that can be suitably used for photosensitive resin compositions include benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, and tertiary amine compounds. And xanthone compounds.

  These photopolymerization initiators, photoinitiator assistants, and sensitizers can be used alone or in combination of two or more. The total amount of such photopolymerization initiator, photoinitiator assistant and sensitizer is preferably 35 parts by mass or less with respect to 100 parts by mass of (A) carboxyl group-containing resin. It can suppress that deep part curability falls by these light absorption as it is 35 mass parts or less.

[(D) Titanium oxide]
(D) The titanium oxide may be rutile type titanium oxide or anatase type titanium oxide, but it is preferable to use rutile type titanium oxide. Anatase-type titanium oxide, which is the same titanium oxide, has higher whiteness compared to rutile-type titanium oxide and is often used as a white pigment. The emitted light may cause discoloration of the resin in the photosensitive resin composition. In contrast, rutile-type titanium oxide is slightly inferior to anatase-type in whiteness, but has almost no photoactivity, so that the resin is deteriorated by light due to the photoactivity of titanium oxide (yellowing). Is remarkably suppressed and is stable against heat. For this reason, when it is used as a white pigment in the insulating layer of the printed wiring board on which the LED is mounted, a high reflectance can be maintained over a long period of time.

  A well-known thing can be used as a rutile type titanium oxide. There are two types of production methods for rutile titanium oxide, a sulfuric acid method and a chlorine method. In the present invention, those produced by any of the production methods can be suitably used. Here, the sulfuric acid method uses ilmenite ore or titanium slag as a raw material, dissolves this in concentrated sulfuric acid, separates iron as iron sulfate, and hydrolyzes the solution to obtain a hydroxide precipitate. A production method in which rutile titanium oxide is taken out by baking at a high temperature. On the other hand, the chlorine method uses synthetic rutile or natural rutile as a raw material, reacts with chlorine gas and carbon at a high temperature of about 1000 ° C to synthesize titanium tetrachloride, and oxidizes this to extract rutile titanium oxide. Say. Among them, rutile-type titanium oxide produced by the chlorine method is particularly effective in suppressing the deterioration (yellowing) of the resin due to heat, and is more preferably used in the present invention.

  Among these titanium oxides, it is particularly preferable to use titanium oxide whose surface is treated with hydrous alumina or aluminum hydroxide from the viewpoints of dispersibility in the composition, storage stability, and flame retardancy.

  Moreover, it is preferable that Y value is 65 or more, and, as for the hardened | cured material formed with the photosensitive resin composition of this invention, it is more preferable that it is 70 or more.

  (D) The compounding quantity of a titanium oxide becomes like this. Preferably it is 30-300 mass parts with respect to 100 mass parts of (A) carboxyl group-containing resin, More preferably, it is 50-250 mass parts. (D) Titanium oxide can be used individually by 1 type or in combination of 2 or more types. Moreover, you may contain other coloring agents other than a titanium oxide in the range which does not impair the effect of this invention.

(D) The titanium oxide may be surface-treated with silica or alumina.
The titanium oxide surface-treated with silica can suppress deterioration against light. Titanium oxide surface-treated with alumina can further improve the reflectivity of the cured product. The titanium oxide surface-treated with silica or alumina can be anatase type or rutile type, but the rutile type is preferred. Further, among the rutile type titanium oxides, those produced by the chlorine method are particularly preferable because the deterioration of the resin is further suppressed.

Examples of the titanium oxide surface-treated with silica or alumina include Typek R-930, Typek R-630, Typek R-680, Typek R-670, Typek CR-50, Typek CR-57, Typek CR-97, and Typek CR. -60, Type CR-63, Type CR-67, Type CR-58, Type UT771, Type R-820, Type R-830, Type R-550, Type R-780, Type R-780-2, Type R -850, Typep R-855, Typep CR-80, Typep CR-90, Typep CR-90, Typep CR-90-2, Typep CR-93, Typep CR-95, Typep CR-953, Typep CR-63, Taipe CR-85 (manufactured by Ishihara Sangyo Co., Ltd.), Taipure R-100, Taipure R-101, Taipure R-102, Taipure R-103, Taipure R-104, Taipure R-105, Taipure R-108, Taipure R-900 , Taipure R-902, Taipure R-960, Taipure R-706, Taipure R-931 (manufactured by DuPont), TITON R-25, TITON R-21, TITON R-32, TITON R-7E, TITON R-5N , TITON R-61N, TITON R-62N, TITON R-42, TITON R-45M, TITON R-44, TITON R-49S, TITON GTR-100, TITON GTR-300, TITON D-918, TITON TCR-29 , TITON TCR- 2, TITON FTR-700 (manufactured by Sakai Chemical Industry Co., Ltd.), TITANIX JR-300, TITANIX JR-403, TITANIX JR-405, TITANIX JR-600A, TITANIX JR-600E, TITANIX JR-602, TITANIX JR-60T JR-603, TITANIX JR-805 (manufactured by Teika) or the like can be used.
Examples of the anatase type titanium oxide include Tyco A-220 (manufactured by Ishihara Sangyo Co., Ltd.), TITANIX JA-4 (manufactured by Teika Co., Ltd.) and the like.

The titanium oxide surface-treated with alumina can be subjected to another surface treatment after being surface-treated with alumina. In particular, the reflectance can be further improved by surface-treating with alumina and further surface-treating with zirconia.
Among the above-mentioned titanium oxides, titanium oxide surface-treated with alumina and then surface-treated with zirconia includes Type CR-57, Type CR-97, Type CR-67 (Ishihara Sangyo Co., Ltd.), R-61N, GTR. -100, GTR-300 (manufactured by Sakai Chemical Industry Co., Ltd.), and TITANIX JR-603 (manufactured by Teika).

(Flame retardants)
The photosensitive resin composition of the present invention preferably contains a conventionally known flame retardant for the purpose of improving the flame retardancy of the resulting cured product. From the viewpoint of the environment, a flame retardant containing no halogen is preferred. As the flame retardant, for example, a phosphorus-containing compound or aluminum hydroxide, magnesium hydroxide, hydrotalcite, boehmite, or the like, which is an inorganic filler that imparts flame retardancy to the resin composition, may be blended. Among flame retardants, phosphorus-containing compounds and metal hydroxides are preferred. A flame retardant can be used individually by 1 type or in combination of 2 or more types.

（式中、Ｒ^５、Ｒ^６およびＲ^７は、それぞれ独立に、ハロゲン原子以外の置換基を示す。） Examples of the phosphorus-containing compound include those known as organic phosphorus flame retardants. Among such organic phosphorus flame retardants, preferred are phosphoric acid esters and condensed phosphoric acid esters, phosphorus element-containing (meth) acrylates, phosphorus-containing compounds having phenolic hydroxyl groups, cyclic phosphazene compounds, phosphazene oligomers, phosphines Examples thereof include acid metal salts and compounds represented by the following general formula (I).

(In the formula, R ⁵ , R ⁶ and R ⁷ each independently represent a substituent other than a halogen atom.)

In the general formula (I), R ⁵ and R ⁶ are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁷ is a carbon atom optionally substituted by a hydrogen atom or a cyano group. Although it is preferable that it is a C1-C4 alkyl group, a 2, 5- dihydroxyphenyl group, or a 3, 5- di-t-butyl-4-hydroxyphenyl group, it is not limited to this.

  Commercially available products of the phosphorus-containing compound represented by the general formula (I) include HCA, SANKO-220, M-ESTER, HCA-HQ (all are trade names of Sankosha), and the like.

The phosphorus element-containing (meth) acrylate is preferably a compound having a phosphorus element and having a plurality of (meth) acryloyl groups in the molecule. Specifically, R ⁵ in the above general formula (I) and Examples include compounds in which R ⁶ is a hydrogen atom and R ⁷ is a (meth) acrylate derivative. Generally, it can be synthesized by a Michael addition reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and a known and commonly used polyfunctional (meth) acrylate monomer.

  Examples of the (meth) acrylate monomer include diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyania. Polyhydric alcohols such as nurate or polyhydric acrylates such as these ethylene oxide adducts, propylene oxide adducts or caprolactone adducts; phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide of these phenols Polyvalent acrylates such as adducts; and urethane acrylates of the above polyalcohols; Polyglycerides of glycidyl ethers such as diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate; and / or melamine acrylate and at least one of the corresponding methacrylates Is mentioned.

The phosphorus-containing compound having a phenolic hydroxyl group has high hydrophobicity and heat resistance, does not deteriorate electrical characteristics due to hydrolysis, and has high solder heat resistance. Further, as an appropriate combination, when an epoxy resin is used among thermosetting resins, there is an advantage that it does not bleed out after curing because it reacts with the epoxy group and is taken into the network. Among the phosphorus-containing compounds having a phenolic hydroxyl group, preferred are those in which R ⁷ in the general formula (I) is a phenyl group substituted with a hydroxyl group. Commercially available products include HCA-HQ manufactured by Sanko Co., Ltd.

  Phosphorus-containing compounds that are oligomers or polymers have the advantage that there is little decrease in bendability due to the influence of the alkyl chain, and there is no bleedout after curing due to the large molecular weight. Commercial products include M-Ester-HP manufactured by Sanko Co., Ltd. and phosphorus-containing Byron 337 manufactured by Toyobo Co., Ltd.

  As the phosphazene oligomer, a phenoxyphosphazene compound is effective, and there are a substituted or unsubstituted phenoxyphosphazene oligomer or a trimer, a tetramer, and a pentamer, and there are liquid and solid powders. It can be preferably used. Commercially available products include FP-100, FP-300, and FP-390 manufactured by Fushimi Pharmaceutical. Among these, a phenoxyphosphazene oligomer substituted with an alkyl group or a polar group such as a hydroxyl group or a cyano group is preferable because it has high solubility in a carboxyl group-containing resin and does not cause problems such as recrystallization even when added in a large amount.

Further, as another phosphazene oligomer, at least one of a phosphorus element-containing dicarboxylic acid represented by the following general formula (II) and its anhydride and an acrylate compound are obtained, and one or more in the molecule It is a compound containing (meth) acrylate.

Examples of the hydrocarbon group having 1 to 6 carbon atoms represented by R ⁸ and R ⁹ in the general formula (II) include an alkyl group having 1 to 6 carbon atoms and an alkenyl having 1 to 6 carbon atoms. Group, cycloalkyl group and phenyl group. Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, secondary butyl group, tertiary butyl group, isobutyl group, pentyl group, isopentyl group, and tertiary pentyl group. Examples of the alkenyl group having 1 to 6 carbon atoms such as hexyl group include vinyl group, allyl group, 3-butenyl group, isobutenyl group, 4-pentenyl group, and 5-hexenyl group. The hydrocarbon group having 1 to 6 carbon atoms may be branched or substituted.

  Examples of the phosphorus element-containing dicarboxylic acid or anhydride thereof include compounds obtained by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with itaconic acid and anhydrides thereof. Thing etc. are mentioned.

As the acrylate compound, an acrylate compound having a functional group that reacts with a carboxyl group or a carboxylic acid anhydride of the dicarboxylic acid or an anhydride thereof is preferable. An acrylate residue can be added by such a reaction. Such an acrylate compound may be a monofunctional acrylate containing one (meth) acrylate group in the molecule or a polyfunctional acrylate containing two or more (meth) acrylate groups in the molecule. Examples of the functional group include an epoxy group, a hydroxyl group, and an amino group. Examples of the acrylate compound having an epoxy group include glycidyl (meth) acrylate and 2-methyl-2,3-epoxypropyl (meth) acrylate. Examples of the acrylate compound having a hydroxyl group include 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate. Examples of the acrylate compound having an amino group include diethylaminoethyl acrylate. Among the functional groups, an epoxy group and a hydroxyl group are more preferable.
A conventionally known reaction method can be used as the reaction method for adding with the functional group.

  Examples of the phosphazene oligomer include mono- or bifunctional phosphazene oligomers obtained by reacting a phosphorus element-containing dicarboxylic acid of the general formula (II) synthesized as described above with glycidyl methacrylate, and the general formula (II ), A bifunctional phosphazene oligomer obtained by reacting a phosphorus element-containing dicarboxylic acid with hydroxy (meth) acrylate and, if necessary, a dialcohol.

  The amount of the acrylate compound added to the phosphorus element-containing dicarboxylic acid represented by the general formula (II) or its anhydride is not particularly limited, but is adjusted so that the phosphorus concentration of the phosphazene oligomer is in the range of 2 to 7%. Thus, an acrylate compound is preferable.

By using the phosphorus element-containing dicarboxylic acid represented by the general formula (II) or its anhydride, a phosphazene oligomer having both ends acrylated can be easily obtained. By using the terminal acrylated phosphazene oligomer obtained in this way, excellent photosensitivity capable of obtaining a flame retardant coating having excellent flexibility and low warpage and no bleeding out during high temperature pressing. Resin composition can be obtained.
The phosphazene oligomer is preferably a bifunctional phosphorus element-containing acrylate from the viewpoints of flexibility and low warpage. When the phosphazene oligomer is bifunctional, the heat resistance is good and the decrease in flexibility can be suppressed.
Moreover, the said phosphazene oligomer may be used individually by 1 type, and may use 2 or more types together.

  Moreover, by using a phosphinic acid metal salt, flame retardance can be improved without impairing the flexibility of the cured coating. By using such a phosphinic acid metal salt excellent in heat resistance, the bleed-out of the flame retardant can be suppressed in the hot press during mounting.

  Specific examples of the phosphinic acid constituting the phosphinic acid metal salt include phosphinic acid, dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, methandi (methylphosphinic acid), benzene-1, 4- (dimethylphosphinic acid), methylphenylphosphinic acid, phenylphosphinic acid, diphenylphosphinic acid and mixtures thereof.

  Examples of the metal component constituting the phosphinate include calcium, magnesium, aluminum, zinc, bismuth, manganese, sodium, and potassium. Of these, calcium, magnesium, aluminum and zinc are preferable.

  Examples of commercially available phosphinic acid metal salts include Clariant's EXOLIT OP 930, EXOLIT OP 935, and the like.

  A phosphorus containing compound may be used individually by 1 type, and may use 2 or more types together. The compounding quantity of a phosphorus containing compound is 5-150 mass parts with respect to 100 mass parts of said (A) carboxyl group-containing resin, Preferably it is 10-100 mass parts. When the amount is 150 parts by mass or less, the bending properties and the like of the obtained cured coating film are good.

  As the metal hydroxide, those that can be decomposed by heating and exhibit flame retardancy such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, and strontium hydroxide can be used. Among these, aluminum hydroxide and magnesium hydroxide can be preferably used.

  Aluminum hydroxide may be untreated surface, using a silane coupling agent having a vinyl group or an epoxy group at its end, stearic acid, oleic acid, phosphoric acid ester, etc. Also good. Commercially available products of aluminum hydroxide include Heidilite H-42, H-42M, H-42S, H-42T, H-42ST-V, H-42ST-E, H-42I, H- manufactured by Showa Denko KK 43, H-43M, H-43S, B1403, B1403ST, B1403T manufactured by Nippon Light Metal Co., Ltd. and the like.

  Magnesium hydroxide may be a natural product or a synthetic product, and may be a surface-untreated one. A silane coupling agent having a vinyl group or an epoxy group at its end, stearic acid, You may use what was surface-treated with oleic acid, phosphoric acid ester, etc. Examples of commercially available magnesium hydroxide include Kisuma 5A, Kisuma 5B, Kisuma 5E, Kisuma 5J, Kisuma 5P, Kisma 5L, Kaluma Chemical, Magnifin H5, Magnifin H7, Magnifin H10, and the like.

  The amount of the inorganic filler that imparts flame retardancy such as aluminum hydroxide or magnesium hydroxide is preferably 500 parts by mass or less, more preferably 0.1 parts per 100 parts by mass of the (A) carboxyl group-containing resin. ˜300 parts by mass, particularly preferably 0.1 to 150 parts by mass. When the compounding quantity of a filler is 500 mass parts or less, the viscosity of a photosensitive resin composition does not become high too much, printability is favorable, and hardened | cured material becomes difficult to become weak.

  The average particle diameter (d50) of the inorganic filler imparting flame retardancy is preferably 30 μm or less, and more preferably 15 μm or less. By setting the average particle size to 30 μm or less, it is possible to make the friction traces less likely to occur. The lower limit value of the average particle diameter (d50) is, for example, 0.05 μm or more. The average particle diameter (d50) can be measured by a laser diffraction / scattering method.

(Thermosetting component)
It is preferable to mix a thermosetting component in the photosensitive resin composition of the present invention. It can be expected that heat resistance is improved by adding a thermosetting component. Any known thermosetting component can be used. For example, known amino resins such as melamine resin, benzoguanamine resin, melamine derivative, benzoguanamine derivative, isocyanate compound, block isocyanate compound, cyclocarbonate compound, polyfunctional epoxy compound, polyfunctional oxetane compound, episulfide resin, bismaleimide, carbodiimide resin, etc. The thermosetting component can be used. Particularly preferred is a thermosetting component having a plurality of cyclic ether groups or cyclic thioether groups (hereinafter abbreviated as cyclic (thio) ether groups) in the molecule. A thermosetting component can be used individually by 1 type or in combination of 2 or more types.

  The thermosetting component having a plurality of cyclic (thio) ether groups in the molecule is a compound having a plurality of 3, 4 or 5-membered cyclic (thio) ether groups in the molecule. A compound having an epoxy group, that is, a polyfunctional epoxy compound, a compound having a plurality of oxetanyl groups in the molecule, that is, a polyfunctional oxetane compound, a compound having a plurality of thioether groups in the molecule, that is, an episulfide resin.

  Polyfunctional epoxy compounds include epoxidized vegetable oils; bisphenol A type epoxy resins; hydroquinone type epoxy resins; bisphenol type epoxy resins; thioether type epoxy resins; brominated epoxy resins; novolac type epoxy resins; biphenol novolac type epoxy resins; Type epoxy resin; hydrogenated bisphenol A type epoxy resin; glycidylamine type epoxy resin; hydantoin type epoxy resin; alicyclic epoxy resin; trihydroxyphenylmethane 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; Tetraphenylol ethane type epoxy resin; Heterocyclic epoxy resin; Diglycidyl Taleate resin; Tetraglycidylxylenoylethane resin; Naphthalene group-containing epoxy resin; Epoxy resin having dicyclopentadiene skeleton; Glycidyl methacrylate copolymer epoxy resin; Copolymer epoxy resin of cyclohexylmaleimide and glycidyl methacrylate; Polybutadiene rubber derivatives; CTBN-modified epoxy resins and the like can be mentioned, but are not limited thereto. These epoxy resins can be used alone or in combination of two or more. Among these, novolak type epoxy resins, bisphenol type epoxy resins, bixylenol type epoxy resins, biphenol type epoxy resins, biphenol novolac type epoxy resins, naphthalene type epoxy resins or mixtures thereof are particularly preferable.

  Examples of the polyfunctional oxetane compound include bis [(3-methyl-3-oxetanylmethoxy) methyl] ether, bis [(3-ethyl-3-oxetanylmethoxy) methyl] ether, 1,4-bis [(3- Methyl-3-oxetanylmethoxy) methyl] benzene, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, (3-methyl-3-oxetanyl) methyl acrylate, (3-ethyl-3- In addition to polyfunctional oxetanes such as oxetanyl) methyl acrylate, (3-methyl-3-oxetanyl) methyl methacrylate, (3-ethyl-3-oxetanyl) methyl methacrylate and oligomers or copolymers thereof, oxetane alcohol and novolak resin , Poly (p-hydroxystyrene), cardo-type bis Phenol ethers, calixarenes, calix resorcin arenes or etherified products such as the resin having a hydroxyl group such as silsesquioxane and the like. In addition, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth) acrylate is also included.

  Examples of the compound having a plurality of cyclic thioether groups in the molecule include bisphenol A type episulfide resin. Moreover, episulfide resin etc. which substituted the oxygen atom of the epoxy group of the novolak-type epoxy resin by the sulfur atom using the same synthesis method can also be used. As for the compounding quantity of the thermosetting component which has several cyclic | annular (thio) ether group in such a molecule | numerator, 0.6-2.5 equivalent is preferable with respect to 1 equivalent of carboxyl groups of (A) carboxyl group-containing resin. . When the blending amount is 0.6 equivalent or more, the carboxyl group hardly remains in the cured product, and the heat resistance, alkali resistance, electrical insulation and the like are good. On the other hand, when the amount is 2.5 equivalents or less, the low molecular weight cyclic (thio) ether group hardly remains in the dry coating film, and the strength of the coating film is good. More preferably, it is 0.8-2.0 equivalent.

  Examples of amino resins such as melamine derivatives and benzoguanamine derivatives include methylol melamine compounds, methylol benzoguanamine compounds, methylol glycoluril compounds, and methylol urea compounds.

  As the isocyanate compound, a polyisocyanate compound can be blended. Examples of the polyisocyanate compound include 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, and Aromatic polyisocyanates such as 2,4-tolylene dimer; Aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylenebis (cyclohexyl isocyanate) and isophorone diisocyanate; Alicyclic polyisocyanates such as heptane triisocyanate; and adducts of the isocyanate compounds listed above, Yuretto body and isocyanurate products thereof.

  As the blocked isocyanate compound, an addition reaction product of an isocyanate compound and an isocyanate blocking agent can be used. As an isocyanate compound which can react with an isocyanate blocking agent, the above-mentioned polyisocyanate compound etc. are mentioned, for example. As an isocyanate block agent, for example, phenol block agent; lactam block agent; active methylene block agent; alcohol block agent; oxime block agent; mercaptan block agent; acid amide block agent; imide block agent; Examples include amine-based blocking agents; imidazole-based blocking agents; imine-based blocking agents.

  As for the compounding quantity of such a polyisocyanate compound or a block isocyanate compound, 1-100 mass parts is preferable with respect to 100 mass parts of (A) carboxyl group-containing resin. When the amount is 1 part by mass or more, sufficient toughness of the coating film is obtained. On the other hand, in the case of 100 mass or less, storage stability is favorable. More preferably, it is 2-70 mass parts.

(Other photopolymerizable monomers)
The photosensitive resin composition of the present invention can contain other photopolymerizable monomers in addition to (B) urethane (meth) acrylate and phosphorus element-containing (meth) acrylate that can be used as a flame retardant. The photopolymerizable monomer is a compound having one or more ethylenically unsaturated groups in the molecule, and is photocured by irradiation with active energy rays to insolubilize the (A) carboxyl group-containing resin in an aqueous alkali solution. Or it helps insolubilization.

  Any known compounds can be used as the other photopolymerizable monomer. For example, conventionally known polyester (meth) acrylate, polyether (meth) acrylate, carbonate (meth) acrylate, epoxy (meth) acrylate can be used, and specifically, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, etc. Hydroxyalkyl acrylates; glycol diacrylates such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, 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; Polyol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate and other polyhydric alcohols or their polyvalent acrylates such as ethylene oxide adduct, propylene oxide adduct, or ε-caprolactone adduct Multivalent acrylates such as phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide adducts of these phenols; glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl Polyvalent acrylates of glycidyl ether such as isocyanurate; not limited to the above, polyether polyol, polycarbonate di Examples thereof include acrylates and melamine acrylates obtained by directly acrylated polyols such as all, hydroxyl-terminated polybutadiene and polyester polyol, and / or methacrylates corresponding to the above acrylates. Other photopolymerizable monomers can be used alone or in combination of two or more.

  The total amount of the photopolymerizable monomer including the (B) urethane (meth) acrylate and the phosphorus element-containing (meth) acrylate that can be used as a flame retardant is preferably based on 100 parts by mass of the (A) carboxyl group-containing resin. Is 10 to 250 parts by mass, more preferably 10 to 200 parts by mass. In the case of 10 parts by mass or more, photocurability is good, and pattern formation is facilitated by alkali development after irradiation with active energy rays. On the other hand, in the case of 250 parts by mass or less, the solubility in an alkaline aqueous solution becomes good, and the decrease in resolution can be suppressed.

(Antioxidant)
In many polymer materials, once oxidation starts, oxidative degradation occurs successively in a chain, resulting in functional deterioration of the polymer material. Therefore, the photosensitive resin composition of the present invention has a (1) ) Antioxidants such as radical scavengers that invalidate the generated radicals and / or (2) peroxide decomposers that decompose the generated peroxides into harmless substances and prevent the generation of new radicals. An agent can be added.

  Specific examples of antioxidants that act as radical scavengers include hydroquinone, 4-tert-butylcatechol, 2-t-butylhydroquinone, hydroquinone monomethyl ether, 2,6-di-t-butyl-p- Cresol, 2,2-methylenebis- (4-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5 Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (3 ′, 5′di-t-butyl-4-hydroxy Benzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione and other phenolic compounds, quinone compounds such as metaquinone and benzoquinone, bis (2,2,6, And amine compounds such as 6-tetramethyl-4-piperidyl) -sebacate and phenothiazine.

  The radical scavenger may be commercially available, for example, ADK STAB AO-30, ADK STAB AO-330, ADK STAB AO-20, ADK STAB LA-77, ADK STAB LA-57, ADK STAB LA-67, ADK STAB LA-68, ADK STAB LA-87 (above, manufactured by ADEKA, trade name), IRGANOX 1010, IRGANOX 1035, IRGANOX 1076, IRGANOX 1135, TINUVIN 111FDL, TINUVIN 123, TINUVIN 144, TINUVIN 152, TINUVIN 292, TINUVIN S Japan 5100, manufactured by TINUVIN S ) And the like. Specific examples of the antioxidant that acts as a peroxide decomposer include phosphorus compounds such as triphenyl phosphite, pentaerythritol tetralauryl thiopropionate, dilauryl thiodipropionate, distearyl 3,3 ′. -Sulfur compounds such as thiodipropionate.

  The peroxide decomposing agent may be commercially available, for example, ADK STAB TPP (manufactured by ADEKA, trade name), Mark AO-412S (manufactured by ADEKA, trade name), Sumilizer TPS (manufactured by Sumitomo Chemical Co., Ltd., commodity) Name).

  Said antioxidant can be used individually by 1 type or in combination of 2 or more types.

(Organic solvent)
In the photosensitive resin composition of the present invention, an organic solvent can be used for (A) synthesis of a carboxyl group-containing resin, preparation of a composition, or adjustment of viscosity for application to a substrate or a carrier film. . Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. More specifically, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl Glycol ethers such as ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate , Esters such as propylene glycol butyl ether acetate; ethanol, propanol Ethylene glycol, or propylene glycol; octane, aliphatic hydrocarbons decane; petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, petroleum solvents such as solvent naphtha. Such an organic solvent can be used individually by 1 type or in combination of 2 or more types.

(Other optional ingredients)
The photosensitive resin composition of the present invention may contain a whitening additive that reduces the b ^* value in the L ^* a ^* b ^* color system of the cured product of the composition by heating. Here, the whitening additive is one that can increase the whiteness of the cured product of the composition and make it appear as if it is not discolored.

Here, in this specification, to decrease the b ^* values of the cured product of the composition by heating is meant the b ^* value decreases upon heating a cured product of the composition first, second Does not include subsequent heating. In addition, the heating temperature in this case is substantially a temperature at which the composition is mounted with solder, and is specifically 200 ° C. or higher, for example, 220 to 370 ° C. A general solder reflow process is performed only once at about 260 ° C. When the whitening additive is heated at a temperature of about 150 ° C., which is the curing temperature of the composition, the b ^* value does not decrease.

（式中、Ｒ^１およびＲ^２は、それぞれ独立に、直鎖または分岐を有していてもよい炭素原子数１〜１２のアルキル基を表す）で表される構造を有する化合物の１種以上を含むことが好ましい。特には、Ｒ^１およびＲ^２がそれぞれ独立に炭素原子数４〜８のアルキル基であるものが好ましく、ブチル基またはオクチル基であるものがより好ましく、具体的には、下記式（Ｉ−１）〜（Ｉ−３）、

（４，４’−［５−ｔ−ブチル−２−ベンズオキサゾリル−４’−（５−ｔ−オクチル−２−ベンズオキサゾリル）］スチルベン）

（４，４’−ビス−［５−ｔ−オクチル−２−ベンズオキサゾリル］スチルベン）

（４，４’−ビス−［５−ｔ−ブチル−２−ベンズオキサゾリル］スチルベン）
で示される化合物のうちのいずれか１種、または、２種以上、特には３種の混合物を好適に使用することができる。また、増白用添加剤としては、分解温度４００℃以上のものが好適である。ここで、増白用添加剤の分解温度を４００℃以上としている理由としては、リフロー工程において３５０℃前後で処理する仕様があり、その熱負荷により添加剤自体が分解することを防止するためである。分解温度の上限値については特に制限はないが、例えば、４００℃〜６００℃である。 As the whitening additive, those having a benzoxazole-based skeleton can be suitably used. Among them, the following formula (I),

(Wherein R ¹ and R ² each independently represents a linear or branched alkyl group having 1 to 12 carbon atoms) and one or more compounds having a structure represented by It is preferable to contain. In particular, R ¹ and R ² are preferably each independently an alkyl group having 4 to 8 carbon atoms, more preferably a butyl group or an octyl group, and specifically, the following formula (I-1 ) To (I-3),

(4,4 ′-[5-tert-butyl-2-benzoxazolyl-4 ′-(5-tert-octyl-2-benzoxazolyl)] stilbene)

(4,4′-bis- [5-t-octyl-2-benzoxazolyl] stilbene)

(4,4′-bis- [5-tert-butyl-2-benzoxazolyl] stilbene)
Any one of the compounds represented by the above, or a mixture of two or more, particularly three, can be preferably used. Further, as the whitening additive, those having a decomposition temperature of 400 ° C. or higher are suitable. Here, the reason why the decomposition temperature of the whitening additive is set to 400 ° C. or more is to prevent the additive itself from being decomposed by the heat load, because there is a specification of processing at around 350 ° C. in the reflow process. is there. Although there is no restriction | limiting in particular about the upper limit of decomposition temperature, For example, it is 400 to 600 degreeC.

  As a compounding quantity of the said whitening additive, it is preferable that it is 0.01-60 mass parts with respect to 100 mass parts of (A) carboxyl group-containing resin, More preferably, it is 0.1-40 mass parts. .

  Moreover, the photosensitive resin composition of this invention may also contain the photoexcitable inorganic filler by which surface treatment was given. The surface-treated photoexcitable inorganic filler is obtained by subjecting a photoexcitable inorganic filler to a surface treatment with an inorganic component or an acidic liquid. By using a photoexcitable inorganic filler that has been subjected to a surface treatment and further satisfying the conditions relating to pH described later, a high reflectance can be realized in the cured coating film. The use of a surface-treated photoexcitable inorganic filler results in the formation of an insoluble or sparingly soluble reaction product on the surface of the photoexcitable inorganic filler and the water resistance of the surface. This is because the effect of maintaining high reflectivity over a long period of time can be obtained even under conditions where water is present.

  Examples of the photoexcitable inorganic filler include strontium aluminate and zinc sulfide. In particular, strontium aluminate can be suitably used. These photoexcitable inorganic fillers may be used alone or in combination of two or more. Examples of the inorganic component used for the surface treatment include silica (glass), alumina, zirconia and the like. As a surface treatment method using an inorganic component, a known method can be used and is not particularly limited.

  In addition, the acid liquid includes nitric acid, hydrochloric acid, carbonic acid, sulfuric acid, sulfurous acid, silicic acid, boric acid, phosphoric acid, phosphorous acid, polyphosphoric acid, primary sodium phosphate, sodium hexametaphosphate, acetic acid, butyric acid, propionic acid , Caprylic acid, lauric acid, stearic acid, acrylic acid, methacrylic acid, oxalic acid, succinic acid, citric acid, malic acid, tartaric acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, salicylic acid, benzoic acid, gallic acid, Acids such as phenol, naphthoic acid, toluene sulfonic acid, benzene sulfonic acid, metanilic acid, taurine, ascorbic acid, silanolic acid, phosphonic acid, crotonic acid, maleic acid, lactic acid, and salts of these acids, such as potassium salt, sodium It is possible to use an acidic compound selected from among acid generating compounds such as salts, ammonium salts, and acid anhydrides. Among these, phosphoric acid, phosphorous acid, polyphosphoric acid, phosphoric acid compounds such as primary phosphoric acid soda and phosphoric acid compounds composed of these salts, and sulfuric acid are preferred, and phosphoric acid compounds are particularly preferred. preferable. Any one of the inorganic component and the acidic liquid can be used alone or in combination of two or more.

  Here, the surface treatment with the acidic liquid can be performed under the condition of pH 3 or less using the acidic liquid. For example, a method of immersing the photoexcitable inorganic filler in an aqueous solution containing the acidic liquid, Examples thereof include a method of spraying the aqueous solution contained on the photoexcitable inorganic filler and a method of bringing the acidic liquid into contact with the surface of the photoexcitable inorganic filler in a high humidity atmosphere. Among these methods, the method of immersing the photoexcitable inorganic filler in an aqueous solution containing an acidic liquid is preferable because the operation is simple and the reaction can be performed efficiently.

  Specifically, first, about 1 to 1000 times by mass, preferably about 2 to 100 times by mass, more preferably about 3 to 10 times by mass water is prepared with respect to the photoexcitable inorganic filler, and the above acidic liquid Is dissolved to a concentration of about 0.01 to 30% by mass, preferably about 0.5 to 10% by mass. At this time, for the purpose of adjusting the solubility of the acidic liquid, a part of the water is added to a water-soluble organic solvent such as methanol, ethanol, acetone, dioxane, dimethylformamide (DMF), dimethyl sulfoxide (DMSO) or the like. It is also possible to replace it. The amount of the organic solvent used in this case is not particularly limited as long as it does not hinder the reaction between the metal oxide of the photoexcitable inorganic filler and the acidic liquid. Also make the amount small. Further, a surfactant may be added to the aqueous solution in order to improve the dispersibility of the photoexcitable inorganic filler. The type and amount used of the surfactant can be appropriately adjusted according to the type and amount of the photoexcitable inorganic filler used.

  Next, a photoexcitable inorganic filler is added to an aqueous solution containing an acidic liquid, and is uniformly dispersed by stirring to react the acidic liquid and the metal oxide of the photoexcitable inorganic filler. The treatment temperature at this time is not particularly limited, but usually the liquid temperature can be about 20 ° C. or more, preferably 50 ° C. to less than the boiling point, and the treatment time is 0.5 to 120 minutes, preferably It can be 10 to 60 minutes.

  After the surface treatment with the acidic liquid, an alkali treatment can be performed using at least one alkaline compound selected from alkalis or alkali-generating compounds. The alkali treatment is performed under conditions of pH 4-9, preferably pH 4-7. By performing the alkali treatment, the durability of the water resistance of the photoexcitable inorganic filler by the surface treatment using the acidic liquid is improved, and the water resistance is maintained even during long-term use at high temperatures. Become. This is considered to be due to the reaction product formed on the surface of the photoexcitable inorganic filler being modified to be stronger by alkali treatment. As the alkali used for the alkali treatment, sodium hydroxide, lithium hydroxide, calcium hydroxide, potassium hydroxide, strontium hydroxide, ammonia and the like are used, and sodium hydroxide is preferably used. Further, as the alkali-generating compound, dibasic sodium phosphate, tribasic sodium phosphate, sodium hexametaphosphate, sodium acetate, strontium oxide, etc. are used, and preferably, tertiary phosphate is used. Furthermore, organic alkaline compounds such as monoethanolamine, triethanolamine, guanidine, stearylamine and pyridine can also be used.

  The means for alkali treatment is not particularly limited, and can be performed, for example, as follows. That is, after the treatment with the acidic liquid, the supernatant is removed and an appropriate amount of water is newly added. Next, it can carry out by adjusting the pH to 4-9 by adding the said alkaline compound gradually, stirring with a mixer etc. Although there is no restriction | limiting in particular about the process temperature in this case, Usually, liquid temperature shall be about 20 degreeC or more, Preferably it is set as the temperature range of 50 to less than a boiling point. The treatment time is usually 0.5 to 120 minutes, preferably 10 to 60 minutes.

  After the alkali treatment, the supernatant is removed, filtered, washed with water, and sufficiently dried to obtain a photoexcitable inorganic filler that has been subjected to the target surface treatment. Although the drying conditions in this case are not particularly limited, the drying may be usually performed at a temperature of 20 ° C. or more for 2 hours or more. The surface-treated photo-excitable inorganic filler can be obtained in a powder form by sieving as necessary. The thus obtained surface-treated photoexcitable inorganic filler has a solubility in 100 g of water at 40 ° C. of less than 1 g and has heat resistance, so it maintains very good water resistance for a long time. Is something that can be done.

  Further, as the photoexcitable inorganic filler subjected to the surface treatment, 10 g of the photoexcitable inorganic filler is put in 50 g of acetone, the primary insoluble component is taken out, and then the taken out primary insoluble component is put in 50 g of chloroform. The secondary insoluble component is taken out, and then the taken out secondary insoluble component is put into 10 g of pure water, and the pH value of the liquid obtained by stirring at 30 ° C. for 1 week is 6 to 12. It is preferable in terms of obtaining a rate.

  As a compounding quantity of a photoexcitable inorganic filler, it is 0.1-500 mass parts with respect to 100 mass parts of (A) carboxyl group resin, for example.

  If necessary, the photosensitive resin composition of the present invention further includes a thermosetting catalyst, a urethanization catalyst, an epoxy curing agent thermoplastic resin, a block copolymer, a filler, a binder polymer, an elastomer, an adhesion promoter, and an antioxidant. Components such as an agent, an ultraviolet absorber and a thermal polymerization inhibitor can be blended. As these, those known in the field of electronic materials can be used. In addition, the photosensitive resin composition of the present invention includes known and commonly used thickeners such as finely divided silica, hydrotalcite, organic bentonite, montmorillonite, silicone-based, fluorine-based, polymer-based antifoaming agents and / or the like. Known and commonly used additives such as leveling agents, imidazole-based, thiazole-based, triazole-based silane coupling agents, rust preventives and the like can be blended.

  The photosensitive resin composition of the present invention is useful for forming a protective layer for a circuit pattern of a printed wiring board, and particularly useful for forming a permanent insulating film. Among them, it is useful as a material to be formed on the outermost layer portion such as a solder resist or a coverlay. In particular, it is useful as a solder resist or coverlay material for flexible printed wiring boards on which light emitting elements such as LEDs are mounted. The flexible printed wiring board provided with the soldering resist formed with the photosensitive resin composition of this invention can be used suitably for back panels, such as LED lighting. In addition, you may use the photosensitive resin composition of this invention not only for a flexible printed wiring board but for a rigid printed wiring board. In addition, you may use the photosensitive resin composition of this invention for formation of a solder dam.

  The photosensitive resin composition of this invention can also be made into the form of the dry film provided with the carrier film (support body) and the layer which consists of the said photosensitive resin composition formed on this carrier film. When forming a dry film, the photosensitive resin composition of the present invention is diluted with the above organic solvent to adjust to an appropriate viscosity, and is applied to a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater. A film can be obtained by applying a uniform thickness on a carrier film with a gravure coater, spray coater or the like, and drying usually at a temperature of 50 to 130 ° C. for 1 to 30 minutes. Although there is no restriction | limiting in particular about a coating film thickness, Generally, it is 1-150 micrometers in the film thickness after drying, Preferably it selects suitably in the range of 10-60 micrometers.

  As the carrier film, a plastic film is used, and a plastic film such as a polyester film such as polyethylene terephthalate, a polyimide film, a polyamideimide film, a polypropylene film, or a polystyrene film is preferably used. Although there is no restriction | limiting in particular about the thickness of a carrier film, Generally, it selects suitably in the range of 10-150 micrometers.

  After the photosensitive resin composition of the present invention is formed on the carrier film, a peelable cover film may be laminated on the film surface for the purpose of preventing dust from adhering to the film surface. preferable. As the peelable cover film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper or the like can be used, and when the cover film is peeled off, the adhesive strength between the film and the carrier film is exceeded. What is necessary is just to have a smaller adhesive force between the membrane and the cover film.

  The photosensitive resin composition of the present invention is adjusted to a viscosity suitable for the coating method with, for example, the organic solvent, and on the substrate, a dip coating method, a flow coating method, a roll coating method, a bar coater method, a screen printing method, A tack-free coating film can be formed by applying the organic solvent contained in the composition at a temperature of about 60 to 100 ° C. by volatile drying (preliminary drying) at a temperature of about 60 to 100 ° C. In the case of a dry film obtained by applying the above composition on a carrier film and drying and winding it as a film, after laminating the photosensitive resin composition layer on the base material so as to come into contact with the base material The resin insulating layer can be formed by peeling off the carrier film.

  Examples of the base material include printed circuit boards and flexible printed circuit boards in which circuits are formed in advance, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber. Copper graded laminates of all grades (FR-4, etc.) using other materials such as epoxy, fluorine, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate ester, etc. A film, a PET film, a glass substrate, a ceramic substrate, a wafer plate, etc. can be mentioned.

  Volatile drying performed after the photosensitive resin composition of the present invention is applied may be performed by using a hot air circulation drying furnace, an IR furnace, a hot plate, a convection oven, or the like (a hot air in a dryer using an air heating type heat source using steam). Can be carried out by using a counter current contact method and a method of spraying a nozzle on a support.

  When the photosensitive resin composition of the present invention contains a thermosetting component, for example, the photosensitive resin composition is heated to a temperature of about 140 to 180 ° C. and thermally cured, so that the carboxyl group of the (A) carboxyl group-containing resin and heat The cured component reacts to form a cured coating film excellent in various properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical characteristics.

  The exposed part (part irradiated with active energy rays) is applied to the coating film obtained after applying the photosensitive resin composition of the present invention and evaporating and drying the solvent (irradiation with active energy rays). ) Is cured. Further, by a contact method (or a non-contact method), exposure is selectively performed with an active energy ray through a photomask having a pattern formed thereon or direct pattern exposure is performed by a laser direct exposure machine, and an unexposed portion is diluted with a dilute alkaline aqueous solution (for example, 0.3 A resist pattern is formed by development with a 3% by mass aqueous sodium carbonate solution).

As an exposure machine used for the active energy ray irradiation, a high-pressure mercury lamp lamp, an ultra-high pressure mercury lamp lamp, a metal halide lamp, a mercury short arc lamp, and the like may be used as long as the apparatus irradiates ultraviolet rays in a range of 350 to 450 nm. Furthermore, a direct drawing apparatus (for example, a laser direct imaging apparatus that directly draws an image with a laser using CAD data from a computer) can also be used. As a laser light source of the direct drawing machine, either a gas laser or a solid laser may be used as long as laser light having a maximum wavelength in the range of 350 to 410 nm is used. The amount of exposure for image formation varies depending on the film thickness and the like, but can be generally in the range of 10 to 100 mJ / cm ² , preferably 20 to 800 mJ / cm ² .

  The developing method can be a dipping method, a shower method, a spray method, a brush method, etc., and as a developing solution, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, Alkaline aqueous solutions such as ammonia and amines can be used.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, “part” and “%” are based on mass unless otherwise specified.

(Synthesis of carboxyl group-containing resin A-1)
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 2400 g (3 of polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol (manufactured by Asahi Kasei Chemicals, T5650J, number average molecular weight 800) Mol), 603 g (4.5 mol) of dimethylolpropionic acid, and 238 g (2.6 mol) of 2-hydroxyethyl acrylate as a monohydroxyl compound. Next, 1887 g (8.5 mol) of isophorone diisocyanate was added as a polyisocyanate, and the mixture was stopped by heating to 60 ° C. while stirring. When the temperature in the reaction vessel began to decrease, the mixture was heated again and stirred at 80 ° C. The reaction was terminated after confirming that the absorption spectrum of the isocyanate group (2280 cm ⁻¹ ) had disappeared in the infrared absorption spectrum. Carbitol acetate was added so that the solid content was 70% by mass. The acid value of the solid content of the obtained carboxyl group-containing resin was 50 mgKOH / g. Hereinafter, the obtained varnish is referred to as a carboxyl group-containing resin solution A-1.

(Preparation of photosensitive resin composition)
The components shown in Table 1 below were blended in the proportions (parts by mass) shown in the table, premixed with a stirrer, and then kneaded with a three-roll mill to prepare a photosensitive resin composition. It was 15 micrometers or less when the dispersion degree of each photosensitive resin composition obtained here was evaluated by the particle size measurement by the grind meter by an Erichsen company.

＊１：ＺＦＲ−１４０１Ｈ（日本化薬社製；固形分量６５％）
＊２：ＵＮ−３３２０ＨＡ（根上工業社製；６官能のウレタンアクリレート）
＊３：ＵＮ−９０４（根上工業社製；１０官能のウレタンアクリレート）
＊４：ＵＮ−３３２０ＨＳＢＡ（根上工業社製；１５官能のウレタンアクリレート）
＊５：ＵＮ−９５２（根上工業社製；１０官能のウレタンアクリレート）
＊６：ＵＮ−９０５（根上工業社製；１５官能のウレタンアクリレート）
＊７：ＥＢＥＣＲＹＬ８４０５（ダイセル・オルネクス社製；４官能のウレタンアクリレート）
＊８：Ｌａｒｍｅｒ ＬＲ８８６３（ＢＡＳＦジャパン社製；ポリエーテル変性アクリレートオリゴマー）
＊９：ルシリンＴＰＯ（ＢＡＳＦジャパン社製；アシルホスフィンオキサイド系光重合開始剤）
＊１０：イルガキュアーＯＸＥ−０２（ＢＡＳＦジャパン社製；オキシムエステル系光重合開始剤）
＊１１：タイペークＣＲ−９７（石原産業社製；ルチル型酸化チタン）
＊１２：フタロシアニンブルー
＊１３：ＨＦＡ−６０６５Ｅ（昭和電工社製）
＊１４：エクソリットＯＰ９３５（クラリアント社製）（平均粒径：２〜３μｍ）
＊１５：ハイジライトＨ−４２Ｍ（昭和電工社製）（平均粒径：１μｍ）
＊１６：ＮＣ−３０００Ｈ（日本化薬社製）
＊１７：ＹＸ−４０００（三菱化学社製）
＊１８：ＫＳ−６６（信越化学工業社製）
＊１９：Ｄｉｓｐｅｒｂｙｋ−１１１（ビックケミー・ジャパン社製）
＊２０：メラミン粉砕品
＊２１：エロジール＃９７４（エポック社製）
＊２２：ダワノールＤＰＭ（ダウケミカル社製）

* 1: ZFR-1401H (manufactured by Nippon Kayaku Co., Ltd .; solid content 65%)
* 2: UN-3320HA (manufactured by Negami Kogyo; hexafunctional urethane acrylate)
* 3: UN-904 (Negami Kogyo Co., Ltd .; 10-functional urethane acrylate)
* 4: UN-3320HSBA (Negami Kogyo Co., Ltd .; 15 functional urethane acrylate)
* 5: UN-952 (Negami Kogyo Co., Ltd .; 10-functional urethane acrylate)
* 6: UN-905 (Negami Kogyo Co., Ltd .; 15 functional urethane acrylate)
* 7: EBECRYL 8405 (manufactured by Daicel Ornex Corp .; tetrafunctional urethane acrylate)
* 8: Larmer LR8863 (manufactured by BASF Japan; polyether-modified acrylate oligomer)
* 9: Lucillin TPO (manufactured by BASF Japan; acylphosphine oxide photopolymerization initiator)
* 10: IRGACURE OXE-02 (manufactured by BASF Japan; oxime ester photopolymerization initiator)
* 11: Taipei CR-97 (Ishihara Sangyo Co., Ltd .; rutile titanium oxide)
* 12: Phthalocyanine blue * 13: HFA-6065E (manufactured by Showa Denko)
* 14: Exorit OP935 (manufactured by Clariant) (average particle size: 2 to 3 μm)
* 15: Heidilite H-42M (Showa Denko) (average particle size: 1 μm)
* 16: NC-3000H (Nippon Kayaku Co., Ltd.)
* 17: YX-4000 (Mitsubishi Chemical Corporation)
* 18: KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.)
* 19: Disperbyk-111 (by Big Chemie Japan)
* 20: Melamine pulverized product * 21: Erogil # 974 (Epoch)
* 22: Dowanol DPM (Dow Chemical Co.)

<Molecular weight measurement of urethane acrylate>
The weight average molecular weight of urethane acrylate was determined in terms of standard polystyrene by GPC method (gel permeation chromatography). The measurement conditions are shown below.
Device: Waters 2695
Column: 2 Waters HPSgel HR MB-L (6.0 mm × 15 cm) and 2 Waters HPSgel HR 1.0 (6.0 mm × 15 cm) Sample dilution method: 0.5% by mass Tetrahydrofuran dilution solvent: Tetrahydrofuran

Performance evaluation:
<Scratch resistance>
The composition of each example and comparative example was applied to a 1.6 mm copper solid FR-4 substrate by screen printing so that the dry film thickness was 20 μm, dried at 80 ° C. for 30 minutes, and allowed to cool to room temperature. . Then, using an off-contact exposure apparatus equipped with an ultra-high pressure mercury lamp (short arc lamp 5 kW), the entire surface is exposed at an optimum exposure amount, and a 1 mass% Na ₂ CO ₃ aqueous solution at 30 ° C. is used under a spray pressure of 0.2 MPa. Development was performed for 2 seconds, and heat curing was performed at 150 ° C. for 60 minutes to obtain an evaluation sample in which a cured coating film was formed. A board (double-sided copper-clad flexible board) with a 35-μm copper foil attached to both sides of an 18-μm polyimide film was placed on the evaluation sample obtained, and a 1 kg weight with a circular 12 mm diameter and flat bottom was placed on it. I put it. In this state, the double-sided copper-clad flexible substrate was pulled about 10 cm in parallel, and whether or not black marks were formed on the coating film was evaluated according to the following criteria.
○: No black mark Δ: Black mark having a width of 1 mm or less x: Black mark having a width exceeding 1 mm or a plurality of black marks having a width of 1 mm or less exist

<Reflectance>
The composition of each Example and Comparative Example was applied to a 1.6 mm thick copper solid FR-4 substrate by screen printing, dried at 80 ° C. for 30 minutes, and allowed to cool to room temperature. Then, using an off-contact exposure apparatus equipped with an ultra-high pressure mercury lamp (short arc lamp 5 kW), the entire surface is exposed at an optimum exposure amount, and a 1 mass% Na ₂ CO ₃ aqueous solution at 30 ° C. is used under a spray pressure of 0.2 MPa. Development was performed for 2 seconds, and heat curing was performed at 150 ° C. for 60 minutes to obtain an evaluation sample in which a cured coating film was formed. About the obtained evaluation sample, the reflectance (%) in 360-740 nm was measured for the coating-film surface with the spectrocolorimeter (CM-2600d, Konica Minolta Sensing Corp. make).

<Resolution>
The composition of each example and comparative example was applied to the 1.6 mm thick copper FR-4 substrate by screen printing so that the dry film thickness was 20 μm, dried at 80 ° C. for 30 minutes, and then released to room temperature. Chilled. This substrate was exposed using an off-contact exposure apparatus equipped with an ultra-high pressure mercury lamp (short arc lamp 5 kW) using a negative pattern with an optimal exposure amount and a line width of a light-shielding portion of 100 μm, and 1 mass% Na _{2 at} 30 ° C. The CO ₃ aqueous solution was developed for 120 seconds under the condition of a spray pressure of 0.2 MPa, and thermally cured at 150 ° C. for 60 minutes to obtain an evaluation sample. The obtained line width of the evaluation sample was measured with an optical microscope and evaluated according to the following evaluation criteria.
○: The blank line width is 70 μm or more. Δ: The blank line width is 50 μm or more. X: The blank line width is less than 50 μm.

<Glossiness>
The composition of each Example and Comparative Example was applied to a 1.6 mm thick copper solid FR-4 substrate by screen printing, dried at 80 ° C. for 30 minutes, and allowed to cool to room temperature. Thereafter, the entire surface is exposed at an optimum exposure amount using an off-contact exposure apparatus equipped with an ultrahigh pressure mercury lamp (short arc lamp 5 kW), and a 1 mass% Na ₂ CO ₃ aqueous solution at 30 ° C. is applied for 120 seconds under a spray pressure of 0.2 MPa. Development was performed, and heat curing was performed at 150 ° C. for 60 minutes to obtain an evaluation sample on which a cured coating film was formed. About the obtained evaluation sample, 60 degree specular reflectance was measured using micro trigloss (made by Bic-Chemie Japan).

<Flame retardance>
The composition of each example and comparative example was applied to a 25 μm thick polyimide film (Kapton 100H) by screen printing, dried at 80 ° C. for 20 minutes, and allowed to cool to room temperature. Further, the entire back surface was similarly applied by screen printing, dried at 80 ° C. for 20 minutes, and allowed to cool to room temperature to obtain a double-side coated substrate. Using this exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp, the entire surface of the solder resist was exposed to this substrate at an optimum exposure amount, and a 1 mass% Na ₂ CO ₃ aqueous solution at 30 ° C. was sprayed at a pressure of 0.2 MPa. Development was performed for 120 seconds, and thermosetting was performed at 150 ° C. for 60 minutes to obtain an evaluation sample. This flame retardant evaluation sample was subjected to a thin material vertical combustion test based on the UL94 standard. Evaluation was expressed as VTM-0 or VTM-1 based on the UL94 standard.

<Bendability>
The composition of each Example and Comparative Example was applied to a 25 μm-thick polyimide film (Kapton 100H manufactured by Toray DuPont) by screen printing, dried at 80 ° C. for 30 minutes, and allowed to cool to room temperature. Thereafter, the entire surface is exposed at an optimum exposure amount using an off-contact exposure apparatus equipped with an ultrahigh pressure mercury lamp (short arc lamp 5 kW), and a 1 mass% Na ₂ CO ₃ aqueous solution at 30 ° C. is applied for 120 seconds under a spray pressure of 0.2 MPa. Development was performed, and heat curing was performed at 150 ° C. for 60 minutes to obtain an evaluation sample on which a cured coating film was formed. About the obtained evaluation sample, after giving a gap of R = 0.8 mm, it bends 180 degree | times once and the crack generation | occurrence | production condition in the cured coating film in that case is observed visually and an optical microscope (magnification x200) And evaluated according to the following evaluation criteria.
○: No cracks were generated even after being bent three times. No cracks were generated at one time, but cracks were generated when bent three times from two times. ×: Cracks were generated when bent one time. did

<Electrical characteristics>
Using the IPC B-25 comb-type electrode B coupon, the compositions of Examples and Comparative Examples were coated on the entire surface by screen printing, dried at 80 ° C. for 30 minutes, and allowed to cool to room temperature. Thereafter, the entire surface is exposed at an optimum exposure amount using an off-contact exposure apparatus equipped with an ultrahigh pressure mercury lamp (short arc lamp 5 kW), and a 1 mass% Na ₂ CO ₃ aqueous solution at 30 ° C. is applied for 120 seconds under a spray pressure of 0.2 MPa. Development was performed and thermosetting was performed at 150 ° C. for 60 minutes to obtain an evaluation sample. A bias voltage of DC 100 V was applied to this comb-shaped electrode, and 85 ° C., 85% R.D. H. The presence or absence of migration after 1,000 hours was confirmed in a constant temperature and humidity chamber, and evaluated according to the following evaluation criteria.
○: No change is observed Δ: Only a slight change ×: Migration occurs

＊３２：重量平均分子量４，９００、官能基数１０のウレタンアクリレートと、重量平均分子量５０，０００、官能基数１５のウレタンアクリレート

* 32: Urethane acrylate having a weight average molecular weight of 4,900 and 10 functional groups, and a urethane acrylate having a weight average molecular weight of 50,000 and 15 functional groups.

  From the results shown in Tables 1 and 2 above, it can be seen that in the case of the photosensitive resin composition of the example, friction marks hardly occur in the cured product. On the other hand, it can be seen that (B) Comparative Examples 1 and 2, which do not contain urethane (meth) acrylate having 6 or more functional groups, tend to cause friction marks on the cured product.

Claims (6)

(A) a carboxyl group-containing resin,
(B) urethane (meth) acrylate having 6 or more functional groups,
(C) a photopolymerization initiator, and
(D) A photosensitive resin composition containing titanium oxide.   The photosensitive resin composition according to claim 1, wherein the weight average molecular weight of the (B) urethane (meth) acrylate having 6 or more functional groups is 1,500 to 200,000.   The photosensitive resin composition according to claim 1, further comprising at least one of a metal hydroxide and a phosphorus compound.   A dry film obtained by applying and drying the photosensitive resin composition according to claim 1 on a film.   Hardened | cured material obtained by hardening | curing the photosensitive resin composition as described in any one of Claims 1-3, or the dry film of Claim 4.   A printed wiring board comprising the cured product according to claim 5.