JP6872302B2 - Black photosensitive resin composition - Google Patents

Description

The present invention relates to a black photosensitive resin composition having excellent resolution and hiding power, and when used as a solder resist for an insulating film, for example, a printed wiring board, the electrodes are made finer and finer. It relates to a black photosensitive resin composition corresponding to the above.

The printed wiring board is used to form a pattern of a conductor circuit on a board and mount electronic components on the soldering lands of the pattern by soldering, and the circuit part excluding the soldering lands is an insulating film ( For example, it is coated with a solder resist film). This prevents the solder from adhering to unnecessary parts when soldering electronic components to the printed wiring board, and also prevents the circuit conductor from being directly exposed to air and corroded by oxidation and humidity. To do.

Further, in recent years, in the electronics field, the demand for miniaturization and weight reduction has further increased, and along with this, in order to arrange more miniaturized electronic components at high density, the fine pitch of the conductor circuit pattern of the printed wiring board has been increased. Miniaturization, miniaturization, and high accuracy are required. In response to this, the solder resist film is also required to have higher performance in various properties such as resolution and hiding power, and one of such solder resist films is black.

As a material for forming a black solder resist film, a solder resist composition in which a colorant to be blended in a carboxyl group-containing resin is a black colorant and one or more colorants other than the black colorant has been proposed. (Patent Document 1). Moreover, carbon black is used as a black colorant. However, since the black solder resist composition of Patent Document 1 is black, it is difficult for light to reach the deep part of the solder resist coating film uniformly, the light curing in the deep part of the solder resist coating film is not sufficient, and the resolution is sufficient. There was a problem that it was not.

On the other hand, if the blending amount of the black colorant is limited in order to obtain resolution, there is a problem that the hiding power of the coating film becomes insufficient.

Japanese Unexamined Patent Publication No. 2008-257045

In view of the above circumstances, an object of the present invention is to provide a black photosensitive resin composition capable of obtaining a cured product having excellent resolution and hiding power without impairing basic characteristics such as sensitivity and insulation reliability. To do.

Aspects of the present invention include (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, (D) an epoxy compound, and (E) a carbon black dispersion. , A black photosensitive resin composition characterized by containing.

In the above aspect, a carbon black dispersion is blended as a black colorant. The carbon black dispersion is a dispersion in which carbon black is dispersed in a dispersion medium of a liquid phase. Therefore, in the above aspect, the carbon black powder is not directly blended into the resin composition.

In the embodiment of the present invention, the particle diameter (D50) of the carbon black contained in the carbon black dispersion (E) having a cumulative volume percentage of 50% by volume is 0.50 μm or less and the cumulative volume percentage is 95% by volume. (D95) is a black photosensitive resin composition having a size of 1.0 μm or less.

In the embodiment of the present invention, the particle size (D50) of the carbon black contained in the carbon black dispersion (E) having a cumulative volume percentage of 50% by volume is 0.25 to 0.30 μm, and the cumulative volume percentage is 95% by volume. A black photosensitive resin composition having a particle size (D95) of 0.40 to 0.60 μm.

An aspect of the present invention is a black photosensitive resin composition, wherein the carbon black dispersion (E) contains carbon black, a resin, and an organic solvent.

An aspect of the present invention is a black photosensitive resin composition characterized in that the carbon black dispersion (E) contains 5.0 to 50% by mass of carbon black.

An aspect of the present invention is a black photosensitive resin composition characterized in that the carbon black contained in the carbon black dispersion (E) contains furnace black.

An aspect of the present invention is a black photosensitive resin composition characterized in that the average primary particle size of the furnace black is 20 to 80 nm and the pH is 2.0 to 8.0.

According to the aspect of the present invention, by blending a carbon black dispersion in which powdered carbon black is dispersed in a dispersion medium of a liquid phase instead of powdered carbon black, basic characteristics such as sensitivity and insulation reliability are obtained. It is possible to obtain a cured product having excellent resolution and hiding power without impairing the above.

According to the aspect of the present invention, the carbon black contained in the carbon black dispersion has a D50 of 0.20 to 0.30 μm and a D95 of 0.40 to 0.60 μm, thereby achieving resolution and hiding power. It can be improved in a well-balanced manner, and the amount of carbon black compounded can be reduced.

Next, each component of the black photosensitive resin composition of the present invention will be described. The black photosensitive resin composition of the present invention comprises (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, (D) an epoxy compound, and (E). Contains a carbon black dispersion.

(A) Carboxylic group-containing photosensitive resin The carboxyl group-containing photosensitive resin is not particularly limited, and examples thereof include resins having one or more photosensitive unsaturated double bonds. As the carboxyl group-containing photosensitive resin, for example, acrylic acid or methacrylic acid (hereinafter referred to as "(meth) acrylic acid") is used in at least a part of the epoxy groups of the polyfunctional epoxy resin having two or more epoxy groups in one molecule. A radically polymerizable unsaturated monocarboxylic acid such as) is reacted to obtain a radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as epoxy (meth) acrylate, and the generated hydroxyl group is subjected to polybasic acid or its own. Examples thereof include a polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as a polybasic acid-modified epoxy (meth) acrylate obtained by reacting an anhydride.

The polyfunctional epoxy resin can be any bifunctional or higher functional epoxy resin. The epoxy equivalent of the polyfunctional epoxy resin is not particularly limited, but the upper limit thereof is preferably 2000 g / eq, more preferably 1000 g / eq, and particularly preferably 500 g / eq. On the other hand, the lower limit is preferably 100 g / eq, and particularly preferably 200 g / eq.

Examples of the polyfunctional epoxy resin include biphenyl aralkyl type epoxy resin, phenyl aralkyl type epoxy resin, biphenyl type epoxy resin, bisphenol A type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, silicone modified epoxy resin and the like. Rubber-modified epoxy resin, ε-caprolactone-modified epoxy resin, bisphenol A type, bisphenol F type, bisphenol AD type and other phenol novolac type epoxy resin, о-cresol novolac type and other cresol novolac type epoxy resin, bisphenol A novolac type epoxy Resin, cyclic aliphatic polyfunctional epoxy resin, glycidyl ester type polyfunctional epoxy resin, glycidylamine type polyfunctional epoxy resin, heterocyclic polyfunctional epoxy resin, bisphenol modified novolac type epoxy resin, polyfunctional modified novolac type epoxy resin, phenol Examples thereof include a condensate type epoxy resin of the same kind and an aromatic aldehyde having a phenolic hydroxyl group. Further, those resins in which halogen atoms such as Br and Cl are introduced may be used. These epoxy resins may be used alone or in combination of two or more. Of these, biphenyl aralkyl type epoxy resin and bisphenol A type epoxy resin are preferable from the viewpoint of improving sensitivity, insulation reliability, and resolution in a well-balanced manner, and biphenyl aralkyl type epoxy resin is preferable from the viewpoint of further improving insulation reliability. Is particularly preferable.

The radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid, and acrylic acid and methacrylic acid are preferable. These radically polymerizable unsaturated monocarboxylic acids may be used alone or in combination of two or more.

The reaction method between the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and for example, the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid are reacted by heating in an appropriate diluent. Can be done.

The polybasic acid or polybasic acid anhydride is for introducing a free carboxyl group into the resin by reacting with a hydroxyl group generated by the reaction of the epoxy resin with a radically polymerizable unsaturated monocarboxylic acid. The polybasic acid or its anhydride is not particularly limited, and either saturated or unsaturated can be used. Polybasic acids include, for example, succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, 4-. Ethyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, methyltetrahydrophthalic acid, methylhexahydro Examples thereof include phthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid and diglycolic acid, and examples of the polybasic acid anhydride include these anhydrides. These compounds may be used alone or in combination of two or more.

In the present invention, the above-mentioned polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin can also be used as a carboxyl group-containing photosensitive resin, but if necessary, the carboxyl group of the above-mentioned polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin can be used. A carboxyl group-containing photosensitive resin in which a radically polymerizable unsaturated group is further introduced by reacting a glycidyl compound having one or more radically polymerizable unsaturated groups with an epoxy group to further improve the photosensitivity. May be.

In the carboxyl group-containing photosensitive resin having further improved photosensitivity, the radically polymerizable unsaturated group is bonded to the side chain of the polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin skeleton by the reaction of the glycidyl compound. , It has high photopolymerization reactivity and can have more excellent photosensitive characteristics. Examples of the compound having one or more radically polymerizable unsaturated group and epoxy group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, pentaerythritol trimethacrylate monoglycidyl ether and the like. Can be mentioned. In addition, a plurality of glycidyl groups may be contained in one molecule. The above-mentioned compound having one or more radically polymerizable unsaturated groups and an epoxy group may be used alone or in combination of two or more.

Further, as the carboxyl group-containing photosensitive resin, an acid-modified urethanized unsaturated monocarboxylic oxide epoxy resin such as an acid-modified urethanized epoxy (meth) acrylate resin may be used. In the acid-modified urethane-modified unsaturated monocarboxylic oxide epoxy resin, first, a radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as epoxy (meth) acrylate is obtained as described above, and the generated hydroxyl group is subjected to the above-mentioned polybasic acid. Alternatively, it can be obtained by reacting the anhydride with a compound having two or more isocyanate groups in one molecule.

The compound having two or more isocyanate groups in one molecule is not particularly limited, and for example, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), methylenebiscyclohexylisocyanate, and the like. Examples thereof include diisocyanates such as trimethylhexamethyl diisocyanate, hexane diisocyanate, hexamethylamine diisocyanate, methylenebiscyclohexylisocyanate, toluenediisocyanate, 1,2-diphenylethanediisocyanate, 1,3-diphenylpropanediisocyanate, diphenylmethane diisocyanate and dicyclohexylmethyldiisocyanate. These compounds may be used alone or in combination of two or more.

In the present invention, the acid-modified urinated unsaturated monocarboxylic oxide epoxy resin such as the above-mentioned acid-modified urethane-modified epoxy (meth) acrylate resin can also be used as the carboxyl group-containing photosensitive resin, but the above-mentioned acid can be used as necessary. A radically polymerizable unsaturated group is further introduced by reacting the carboxyl group of the modified urethaneized unsaturated monocarboxylic oxide epoxy resin with a glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group described above. However, it may be a carboxyl group-containing photosensitive resin having further improved photosensitivity.

The acid value of the carboxyl group-containing photosensitive resin is not particularly limited, but the lower limit thereof is preferably 30 mgKOH / g and particularly preferably 40 mgKOH / g from the viewpoint of reliable alkaline development. On the other hand, the upper limit of the acid value is preferably 200 mgKOH / g from the viewpoint of preventing dissolution of the exposed portion by the alkaline developer, and particularly preferably 150 mgKOH / g from the viewpoint of moisture resistance of the cured product and prevention of deterioration of electrical characteristics.

The mass average molecular weight of the carboxyl group-containing photosensitive resin is not particularly limited, but the lower limit thereof is preferably 3000 from the viewpoint of toughness of the cured product and dryness to the touch, and particularly preferably 5000. On the other hand, the upper limit of the mass average molecular weight is preferably 200,000, particularly preferably 50,000, from the viewpoint of smooth alkali developability.

The carboxyl group-containing photosensitive resin may be synthesized by the above reaction steps using each of the above raw materials, or a commercially available carboxyl group-containing photosensitive resin may be used. Examples of the carboxyl group-containing photosensitive resin on the market include "SP-4621" (Showa Denko KK), "ZAR-2000", "ZFR-1212", "FLX-2089", and "ZCR-1569H". (As mentioned above, Nippon Kayaku Co., Ltd.), "Cyclomer P (ACA) Z-250" (Dycel Ornex Co., Ltd.) and the like can be mentioned. Further, these resins may be used alone or in combination of two or more.

(B) Photopolymerization Initiator The photopolymerization initiator is not particularly limited as long as it is generally used, and any of them can be used. Specifically, for example, 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], ethanone 1- [9-ethyl-6- (2-methylbenzoyl)- 9H-carbazole-3-yl] -1- (0-acetyloxime), (Z)-(9-ethyl-6-nitro-9H-carbazole-3-yl) (4-((1-methoxypropane-2) -Il) oxy) -2-methylphenyl) methanone O-acetyloxime, 2- (acetyloxyiminomethyl) thioxanthene-9-one, 1,8-octanedione, 1,8-bis [9-ethyl-6 -Nitro-9H-carbazole-3-yl]-, 1,8-bis (O-acetyloxime), 1,8-octanedione, 1,8-bis [9- (2-ethylhexyl) -6-nitro- 9H-carbazole-3-yl]-, 1,8-bis (O-acetyloxime), (Z)-(9-ethyl-6-nitro-9H-carbazole-3-yl) (4-((1-(1-) Oxime ester compounds such as methoxypropan-2-yl) oxy) -2-methylphenyl) methanone O-acetyloxime, phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide, benzoin, benzoin methyl ether, benzoin Ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-methyl-4 '-(Methylthio) -2-morpholinopropiophenone 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenylketone, 4- (2-hydroxyethoxy) phenyl-2-( Hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary butylanthraquinone, 2-aminoanthraquinone, 2 -Methylthioxanthone, 2-Ethylthioxanthone, 2-Chlorthioxanthone, 2,4-Dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetphenonedimethylketal, P-dimethyla Examples thereof include minobenzoic acid ethyl ester. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited, and is preferably 0.1 part by mass to 10 parts by mass, particularly 0.2 parts by mass to 5 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin. preferable.

(C) Reactive Diluent The reactive diluent is, for example, a photopolymerizable monomer and is a compound having at least one polymerizable double bond per molecule, preferably at least two polymerizable double bonds per molecule. The reactive diluent is used to sufficiently photocure the black photosensitive resin composition to obtain a cured product having acid resistance, heat resistance, alkali resistance and the like.

The reactive diluent is not particularly limited as long as it is the above compound, and is, for example, 2-hydroxyethyl methacrylate, phenoxyethyl methacrylate, diethylene glucol monomethacrylate, 2-hydroxy-3-phenoxypropyl acryliclate, 1,4-. Butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, neo-hydroxypivalate Pentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified di (meth) acrylate, cyclohexyl di (meth) acrylate, isocyanurate. Di (meth) acrylate, trimethylolpropantri (meth) acrylate, ditrimethylolpropantetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, Propylene oxide-modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) ) Acrylate, urethane (meth) acrylates and the like can be mentioned. These may be used alone or in combination of two or more.

The content of the reactive diluent is not particularly limited, and is preferably 2.0 to 100 parts by mass, particularly preferably 10 to 50 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin.

(D) Epoxy compound The epoxy compound is for increasing the crosslink density of the cured product to obtain a cured product having sufficient strength, and examples thereof include an epoxy resin. Examples of the epoxy resin include biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, bisphenol A type epoxy resin, and novolac type epoxy resin (phenol novolac type epoxy resin, o-cresol novolac type epoxy resin, p-tert-butylphenol novolac type). Etc.), bisphenol F type or bisphenol S type epoxy resin obtained by reacting bisphenol F or bisphenol S with epichlorohydrin, and an alicyclic epoxy resin having a cyclohexene oxide group, a tricyclodecane oxide group, a cyclopentene oxide group, etc. Examples thereof include triglycidyl isocyanurate having a triazine ring such as tris (2,3-epoxypropyl) isocyanurate and triglycidyltris (2-hydroxyethyl) isocyanurate, dicyclopentadiene type epoxy resin, and adamantan type epoxy resin. .. These compounds may be used alone or in combination of two or more. Of these, biphenyl aralkyl type epoxy resin and bisphenol A type epoxy resin are preferable from the viewpoint of improving sensitivity, insulation reliability, and resolution in a well-balanced manner, and biphenyl aralkyl type epoxy resin is preferable from the viewpoint of further improving resolution. Is particularly preferable. When a polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin is used as the carboxyl group-containing photosensitive resin, the epoxy resin type used as the basic skeleton of the carboxyl group-containing photosensitive resin is used as the epoxy compound. It is preferable to use it.

The content of the epoxy compound is not particularly limited, and is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin, from the viewpoint of obtaining a coating film having sufficient strength after curing. 100 parts by mass is particularly preferable.

(E) Carbon black dispersion The carbon black dispersion is a dispersion medium in which carbon black is dispersed. Specific examples include a mixture of an organic solvent, a resin, and carbon black powder.

The organic solvent is not particularly limited, and for example, esters such as ethyl diglycol acetate, methoxypropyl acetate, ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, ethanol, propanol, ethylene glycol, propylene glycol and the like. Alcohols, methyl ethyl ketone, ketones such as cyclohexanone; aromatic hydrocarbons such as toluene, xylene, tetramethylbenzene; methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, diethylene glycol monomethyl Examples thereof include glycol ethers such as ether, diethylene glycol monoethyl ether, diproprene glycol monoethyl ether, and triethylene glycol monoethyl ether.

Examples of the resin include urethane resin, epoxy resin, acrylic resin, phenol resin and the like.

The particle size distribution of carbon black is not particularly limited, but for example, the upper limit of the particle size (D50) having a cumulative volume percentage of 50% by volume is preferably 0.50 μm from the viewpoint of reliably obtaining resolution and hiding power. 0.30 μm is more preferable from the viewpoint of improving the resolution and the hiding power in a well-balanced manner, and 0.25 μm is particularly preferable from the viewpoint of improving the resolution and the hiding power in a well-balanced manner while reducing the blending amount. On the other hand, the lower limit of D50 is preferably 0.10 μm from the viewpoint of good dispersibility in the carbon black dispersion, more preferably 0.15 μm, and particularly preferably 0.20 μm from the viewpoint of further improving the resolution. ..

The upper limit of the particle size (D95) having a cumulative volume percentage of 95% by volume is preferably 1.0 μm from the viewpoint of reliably obtaining resolution and hiding power, and is 0 from the viewpoint of improving resolution and hiding power in a well-balanced manner. .80 μm is more preferable, and 0.60 μm is particularly preferable from the viewpoint of improving the resolution and the hiding power in a well-balanced manner while reducing the blending amount. On the other hand, the lower limit of D95 is preferably 0.30 μm, more preferably 0.40 μm, and particularly preferably 0.45 μm from the viewpoint of good dispersibility in the carbon black dispersion.

The particle size distribution of carbon black is particularly 0.25 to 0.30 μm for D50 and 0.40 to 0.60 μm for D95 from the viewpoint of improving the resolution and hiding power in a well-balanced manner while reducing the blending amount. preferable. As a means for adjusting the particle size distribution of carbon black, for example, when preparing a carbon black dispersion, a pulverizer for mixing and dispersing fine powder (for example, a bead mill, a pearl mill, a ball mill, a jet mill, a sand mill, etc.) It is possible to use a mill dispersion method using an attritor or the like. The degree of crushing, that is, the particle size distribution can be adjusted by adjusting the operating speed (crushing energy), raw material supply speed, bead diameter, etc. of the crusher for producing fine powder.

The proportion of carbon black contained in the carbon black dispersion is not particularly limited, but for example, the upper limit thereof is preferably 50% by mass, preferably 20% by mass, from the viewpoint of dispersibility of the carbon black dispersion in the resin composition. Especially preferable. On the other hand, the lower limit is preferably 5.0% by mass, and particularly preferably 10% by mass, from the viewpoint of reliably obtaining resolution and hiding power.

The content of carbon black is not particularly limited, but the upper limit thereof is, for example, 20 mass by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin from the viewpoint of flexibility of the cured product and excellent insulation reliability. Parts are preferable, and 10 parts by mass is particularly preferable. On the other hand, the lower limit is preferably 0.5 parts by mass and particularly preferably 1.0 part by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin from the viewpoint of surely improving the hiding power.

Further, as the carbon black contained in the carbon black dispersion, furnace black produced by the furnace method may be used from the viewpoint of surely improving the hiding power. The average primary particle size of the furnace black is not particularly limited, but the lower limit thereof is preferably 20 nm from the viewpoint of preventing reaggregation, and particularly preferably 35 nm from the viewpoint of further improving the hiding power. The upper limit is preferably 80 nm from the viewpoint of dispersing in the resin composition at a high concentration, and particularly preferably 75 nm from the viewpoint of further improving the hiding power. The pH of furnace black is not particularly limited, but its lower limit is preferably 2.0 from the viewpoint of chemical resistance, and its upper limit is preferably 8.0 from the viewpoint of preventing color unevenness.

In the black photosensitive resin composition of the present invention, in addition to the above-mentioned components (A) to (E), various components such as extender pigment, flame retardant, curing accelerator, defoaming agent, if necessary, A non-reactive diluent or the like can be blended.

The extender pigment contributes to increasing the physical strength of the coating film of the black photosensitive resin composition, and examples thereof include talc, barium sulfate, silica, alumina, aluminum hydroxide, and mica.

The flame retardant is not particularly limited, and known flame retardants can be used. Examples of the flame retardant include a phosphorus element-containing compound. Specific examples of the phosphorus element-containing compound include tris (chloroethyl) phosphate, tris (2,3-dichloropropyl) phosphate, tris (2-chloropropyl) phosphate, tris (2,3-bromopropyl) phosphate, and tris (bromo). Halogen-containing phosphates such as chloropropyl) phosphate, 2,3-dibromopropyl-2,3-chloropropyl phosphate, tris (tribromophenyl) phosphate, tris (dibromophenyl) phosphate, tris (tribromoneopentyl) phosphate. Esters; non-halogen aliphatic phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate; triphenyl phosphate, cresyldiphenyl phosphate, dicredylphenyl phosphate, tricresyl phosphate, trixylate Nylphosphate, xylenyldiphenyl phosphate, tris (isopropylphenyl) phosphate, isopropylphenyldiphenyl phosphate, diisopropylphenylphenyl phosphate, tris (trimethylphenyl) phosphate, tris (t-butylphenyl) phosphate, hydroxyphenyldiphenyl phosphate, octyldiphenyl phosphate , 3-Glysidyloxypropylene diphenylphosphine oxide, 3-Glysidyloxydiphenylphosphine oxide, diphenylvinylphosphine oxide, 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, Non-halogen aromatic phosphate ester such as 2- (9,10-dihydro-9-oxa-10-oxide-10-phosphenylentrene-10-yl) bis- (2-hydroxyethyl) -ester polymer of methylsuccinate Aluminum trisdiethylphosphineate, aluminum diethylphosphineate, aluminum trismethylethylphosphineate, aluminum trisdiphenylphosphine, zinc bisdiphenylphosphine, zinc bismethylethylphosphine, zinc bisdiphenylphosphine, titanyl bisdiphenylphosphine, Titanium tetrakisdiethylphosphine, titanyl bismethylethylphosphine, titanium tetrakismethylethylphosphine, tita bisdiphenylphosphine Cyclic or chain phosphazene with substituted or unsubstituted phenoxy group or substituted or unsubstituted naphthoxy group such as metal salt of phosphinic acid such as nyl, titanium tetraxidiphenylphosphine, cyclic phenoxyphosphazene, cyclic cyanophenoxyphosphazene Examples include compounds, triallylphosphine and the like.

Examples of the curing accelerator include dicyandiamide (DICY) and its derivative, organic acid hydrazide, diaminomaleonitrile (DAMN) and its derivative, guanamine and its derivative, melamine and its derivative, amineimide (AI) and the like. In addition, examples of the defoaming agent include silicone-based, hydrocarbon-based, and acrylic-based.

The non-reactive diluent is for adjusting the drying property and the coating viscosity of the black photosensitive resin composition, and examples thereof include an organic solvent. Organic solvents include, for example, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethyl benzene; methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol and propylene glycol monomethyl ether. , Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diproprene glycol monoethyl ether, triethylene glycol monoethyl ether and other glycol ethers; ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene Esters such as glycol monomethyl ether acetate and esterified products of the above glycol ethers; alcohols such as ethanol, propanol, ethylene glycol and propylene glycol can be mentioned.

The method for producing the black photosensitive resin composition described above is not limited to a specific method, but for example, each of the above components can be blended in a predetermined ratio and then mixed and dispersed by three rolls at room temperature. Further, if necessary, premixing may be performed with a stirrer before the mixing and dispersion.

Next, an example of how to use the black photosensitive resin composition of the present invention will be described. Here, a method of applying the black photosensitive resin composition of the present invention as an insulating protective film (for example, a solder resist film) of a printed wiring board will be described as an example.

The black photosensitive resin composition of the present invention obtained as described above is applied to a printed wiring board, which is a substrate having a circuit pattern formed by etching a copper foil, for example, by a screen printing method, a bar coater method, or a blade. A coating film is formed by applying a desired thickness by a known method such as a coater method, a knife coater method, a roll coater method, a gravure coater method, or a spray coater method. Next, when the black photosensitive resin composition contains a non-reactive diluent such as an organic solvent, 15 to 60 at a temperature of about 60 to 80 ° C. to volatilize the non-reactive diluent. Pre-drying by heating for about a minute is performed to form a tack-free coating film.

Next, a negative film (photomask) having a translucent pattern other than the land of the circuit pattern is brought into close contact with the pre-dried coating film, and ultraviolet rays (for example, a wavelength in the range of 300 to 400 nm) are adhered from above. ) Is irradiated. Then, the coating film is developed by removing the non-exposed region corresponding to the land with a dilute alkaline aqueous solution. A spray method, a shower method, or the like is used as the developing method, and examples of the dilute alkaline aqueous solution used include a 0.5 to 5% by mass sodium carbonate aqueous solution. Next, by performing post-cure for 20 to 80 minutes in a hot air circulation type dryer or the like at 130 to 170 ° C., an insulating protective film such as a target solder resist film can be formed on the printed wiring board.

Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

Examples 1-8, Comparative Examples 1-3
Each component shown in Table 1 below is blended in the ratio shown in Table 1 below, mixed and dispersed at room temperature using three rolls, and black photosensitive used in Examples 1 to 8 and Comparative Examples 1 to 3. A sex resin composition was prepared. The numbers in Table 1 below indicate parts by mass. In addition, the blanks in Table 1 below mean that there is no compounding.

The details of each component in Table 1 are as follows.

(A) Carboxylic group-containing photosensitive resin, KAYARAD ZAR-2000, KAYARAD ZCR-1569H: Nippon Kayaku Co., Ltd.
(B) Photopolymerization Initiator, NCI-831: ADEKA CORPORATION
(C) Reactive diluent, EBECRYL 8405: Daicel, Cytec Co., Ltd. (D) Epoxy compound, EPICLON 850-S: DIC Corporation
・ NC-3000: Nippon Kayaku Co., Ltd.

Carbon Black MA-14, MA-7: Mitsubishi Chemical Corporation
・ Denka Black: Electrochemical Industry Co., Ltd.

Constituent Pigment Heidi Light H42M: Showa Denko KK
Flame Retardant / Exolit OP-935: Clariant Japan Co., Ltd.
Curing accelerator, melamine: Nissan Chemical Industries, Ltd.
・ DICY-7: Mitsubishi Chemical Corporation
Defoamer X-50-1095C: Shin-Etsu Chemical Co., Ltd.
Non-reactive diluent / EDGAC: Sanyo Kasei Co., Ltd.

The carbon black dispersion is 15 parts by mass / 5 parts by mass / 77 parts by mass of carbon black (MA-14, MA-7) / urethane resin (urethane acrylate: EBECRYL 8405) / ethyldiglycol acetate / methoxypropyl acetate. It was prepared by mixing and dispersing with a ball mill at a ratio of parts by mass. The particle size distribution in Table 1 below was adjusted by controlling the operating conditions (crushing energy) of the ball mill, the bead diameter, and the raw material supply rate. D50 and D95 were identified by measuring the particle size distribution with a dynamic light scattering type particle size measuring device (COOLTER “Laser Diffraction Particle Size Analyzer LS130”).

Test piece manufacturing process After surface-treating a flexible wiring board substrate with a circuit pattern formed on a polyimide film (Toray DuPont Co., Ltd. "Kapton 100H") with dilute sulfuric acid (3% by mass), the above method is used for screen printing. After applying the black photosensitive resin composition prepared as described above, it was pre-dried at 80 ° C. for 20 minutes in a BOX furnace. ^{After pre-drying, the coating film is exposed to 100 mJ / cm 2} with an exposure device (Oak Co., Ltd. "HMW-680GW"), developed at 30 ° C. with 1% by mass sodium carbonate developer, and then in a BOX furnace. A cured coating film was formed on the substrate by curing at 150 ° C. for 60 minutes. The thickness of the cured coating film (DRY film thickness) was 20 μm.

The evaluation items are as follows.
(1) Transmittance A cured coating film of a black photosensitive resin composition was formed on a glass plate so as to have a DRY film thickness of 20 μm according to the above-mentioned test piece manufacturing step. Then, the transmittance at a wavelength of 400 nm was measured using the transmittance of the glass plate as a baseline (measuring device: UV spectrophotometer U-3310 (Hitachi High Technology Co., Ltd.).

(2) Sensitivity A step tablet for sensitivity measurement (Kodak Co., Ltd., 21 steps) is installed on the coated substrate after pre-drying at 80 ° C. for 20 minutes according to the above test piece preparation step, and steps are taken. A test piece was obtained by irradiating ultraviolet rays (main peak wavelength 365 nm) through a tablet at 100 mJ / cm ² using an integrated photometer (Oak Co., Ltd.), and a developing solution of 1 mass% sodium carbonate aqueous solution was used. It was used and developed at a spray pressure of ^{2.0 kg / cm 2 for 60 seconds.} The unremoved portion of the exposed portion after development is represented by a number (number of steps). The larger the number of steps, the better the photosensitive characteristics.

(3) Resolvability According to the above test piece manufacturing process, the coating film after pre-drying on the copper-clad laminate is exposed through a photomask (line 30 to 130 μm) so that the DRY film thickness is 30 μm. A cured coating film of the black photosensitive resin composition was formed. The remaining lines of the formed exposed portion were visually confirmed and evaluated.

(4) Insulation reliability According to the above test piece manufacturing process, using the comb-shaped electrode of the IPC-SM840B B-25 test coupon of IPC-TM-650, 85 ° C., 85% R. H. The insulation resistance after humidifying for 200 hours was measured by applying DC50V.
⊚: 1.0 × 10 ¹³ Ω or more.
◯: The insulation resistance value is 1.0 × 10 ¹² Ω or more and ^{less than 1.0 × 10 13} Ω.
Δ: The insulation resistance value is 1.0 × 10 ¹⁰ Ω or more and ^{less than 1.0 × 10 12} Ω.
X: The insulation resistance value is less than ^{1.0 × 10 10 Ω.}

The results of the above evaluation are shown in Table 1 below.

As shown in Table 1 above, in Examples 1 to 8 in which a carbon black dispersion was blended instead of carbon black, the transmittance was 15% or less and the resolution was 110 μm or less, and excellent hiding power was obtained. A cured coating film having resolvability could be obtained. In addition, sensitivity and insulation reliability were also obtained. In particular, from the comparison between Examples 1 and 2 and Examples 3 and 4, when a carbon black dispersion having a carbon black D50 of 0.23 to 0.27 μm is blended, the carbon black D50 is 0.15 to 0.17 μm. Compared with the carbon black dispersion of No. 1, the resolution was further improved in spite of the large amount of carbon black compounded. Further, from Examples 3 and 4, in the carbon black dispersion having a carbon black D50 of 0.23 μm and a D95 of 0.56 μm, the carbon black dispersion having a carbon black D50 of 0.27 μm and a D95 of 0.68 μm is more than the carbon black dispersion. However, the same hiding power and resolution could be obtained with a small amount of compounding. Further, from the comparison between Examples 3 and 5 and Example 6, in the carbon black dispersion having a carbon black D50 of 0.27 μm and a D95 of 0.68 μm, the carbon black D50 is 0.23 μm and D95 is 0.56 μm. It was possible to obtain better resolution than the carbon black dispersion having a carbon black D50 of 0.15 μm and a carbon black D95 of 0.40 μm. Further, from the comparison between Examples 1 to 6 and Examples 7 and 8, a polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin was used as the carboxyl group-containing photosensitive resin, and the carboxyl group-containing photosensitive resin was used. When a biphenylaralkyl type epoxy resin was used as the basic skeleton, the insulation reliability was further improved. Further, from the comparison between Examples 7 and 8, the same epoxy resin type as the epoxy resin type used as the basic skeleton of the carboxyl group-containing photosensitive resin (biphenyl aralkyl type epoxy resin in Examples 7 and 8) as the epoxy compound. When (in Example 8, a biphenyl aralkyl type epoxy resin) was used, the resolution was further improved.

On the other hand, in Comparative Examples 1 to 3 in which powdered carbon black was directly blended into the resin composition, either the transmittance (concealing power) or the resolution was insufficient.

With the black photosensitive resin composition of the present invention, a cured product having excellent resolution and hiding power can be obtained without impairing basic characteristics such as sensitivity and insulation reliability. Therefore, for example, a printed wiring board can be used. It has high utility value in the field of insulating coatings to be coated (for example, solder resist films).

Claims (7)

It contains (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, (D) an epoxy compound, and (E) a carbon black dispersion.
The carbon black contained in the (E) carbon black dispersion is contained in an amount of 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the (A) carboxyl group-containing photosensitive resin.
The carbon black contained in the (E) carbon black dispersion has a particle size (D50) of 0.25 to 0.30 μm with a cumulative volume percentage of 50% by volume.
A black photosensitive resin composition for solder resist of printed wiring boards. The black photosensitive resin according to claim 1, wherein the carbon black contained in the (E) carbon black dispersion has a particle size (D95) of 95% by volume and a particle size (D95) of 1.0 μm or less. Composition. The invention according to claim 1 or 2, wherein the carbon black contained in the carbon black dispersion (E) has a particle size (D95) of 0.40 to 0.60 μm with a cumulative volume percentage of 95% by volume. Black photosensitive resin composition. The black photosensitive resin composition according to any one of claims 1 to 3, wherein the carbon black dispersion (E) contains carbon black, a resin, and an organic solvent. The black photosensitive resin composition according to any one of claims 1 to 4 , wherein the proportion of carbon black contained in the (E) carbon black dispersion is 5.0 to 50% by mass. .. The black photosensitive resin composition according to any one of claims 1 to 5, wherein the carbon black contained in the (E) carbon black dispersion contains furnace black. The black photosensitive resin composition according to claim 6, wherein the furnace black has an average primary particle size of 20 to 80 nm and a pH of 2.0 to 8.0.