Photoinitiator, photosensitive resin composition and use thereof

Abstract

Provided in the present application are a photoinitiator, a photosensitive resin composition and the use thereof. The photoinitiator is a 2,2'-bis(2-alkoxyphenyl)-4,4',5,5'-tetraphenylbiimidazole photoinitiator having a structure as represented by formula (I). The photosensitive resin composition comprises: (A) the 2,2'-bis(2-alkoxyphenyl)-4,4',5,5'-tetraphenylbiimidazole photoinitiator; (B) an alkali-soluble polymer; and (C) a compound having an olefinically unsaturated double bond. The photoinitiator of the present application can make the photosensitive resin composition have an intact resist pattern with a substantially vertical sidewall profile; moreover, the photosensitive resin composition has good dispersion stability, relatively high resolution and relatively good sensitivity, and can also meet the requirements of European Union restrictions on halogens.

Description

A photoinitiator, a photosensitive resin composition and application thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of photocuring, and in particular relates to a photoinitiator, a photosensitive resin composition and application thereof. BACKGROUND

[0002] In recent years, with the miniaturization of printed circuit boards used in precision electronic devices such as mobile phones and wearable devices, photosensitive resin compositions with high photosensitivity, high resolution and resolution have become a hot research topic. As one of the essential components in photosensitive resin compositions, hexaarylbiimidazole (HABI) compounds have a special chemical structure and can photolyze to produce macromolecular radicals under the action of ultraviolet light. They are a very important class of photoinitiators in the field of photocuring, especially in the field of free radical polymerization.

[0003] Among HABI photoinitiators, 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl diimidazole (commonly referred to as "BCIM") and 2,2',5-tris(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenyl diimidazole (commonly referred to as "TCDM-HABI") are the most widely used.

[0004] However, with the increasingly stringent requirements of the EU Halogen Directive 2002 / 95 / EC (regulations on printed board materials), the regulations have increasingly stringent requirements on the use of halogens (requiring the use of chlorine, bromine and total halogen to be limited, with bromine and chlorine contents less than 900 ppm and bromine plus chlorine less than 1500 ppm), which limits the use of BCIM and TCDM-HABI.

[0005] On the other hand, the prior art has the problem of incomplete resist pattern, and because the HABI initiator is used in large quantities, the dispersibility in the photosensitive composition is poor, which easily precipitates in the photosensitive composition, resulting in insufficient yield and the like.

[0006] Therefore, in order to make up for the deficiencies of the prior art and meet the production needs of downstream customers for efficient production and reduced maintenance costs, it is very important to develop a dry film resist that meets the regulatory requirements and has good resist pattern and good dispersion stability. SUMMARY

[0007] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of protection of the claims.

[0008] In view of the deficiencies of the prior art, the purpose of the present application is to provide a photoinitiator, a photosensitive resin composition and an application thereof, so as to solve the problem of incomplete resist pattern in the development process of the photosensitive resin composition in the prior art, and also to meet the requirements of the EU halogen directive.

[0009] To achieve this purpose, the present application adopts the following technical solutions:

[0010] In one aspect, the present application provides a 2,2'-di(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator, wherein the structure of the photoinitiator is shown as formula (I),

[0011] wherein R represents a C3-C8 linear or branched alkyl group.

[0012] In the present application, the C3-C8 linear or branched alkyl group can be a C3, C4, C5, C6, C7 or C8 linear or branched alkyl group.

[0013] In one embodiment, R is selected from n-propyl, i-propyl, n-butyl, i-butyl, n-pentyl, n-hexyl, n-heptyl or n-octyl.

[0014] In the present application, by way of example, the 2,2'-di(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator of the present application can be selected from or include (but not limited to):

[0015] The 2,2'-di(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator of the present application mainly contains 1-2', 2'-3 two connections, and the content is greater than 98%. In the present application, the component content in the 2,2'-di(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator is detected by high performance liquid chromatograph.

[0016] In addition to the above 1-2', 2'-3 two connections, optionally, the 2,2'-di(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator of the present application can also contain a small amount of isomers of 1-4', 1-5', 3-4', 3-5' and the like. From the perspective of formulation stability, the content of other connection site isomers is less than 2%.

[0017] The 2,2'-di(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator of the present application, R represents C3-C8 linear or branched alkyl. When the number of carbon atoms is less than or equal to 2, the formulation dispersibility of the photoinitiator is poor, and it is easy to precipitate in the dry film; when the number of carbon atoms is greater than or equal to 9, the initiator will migrate to the surface of the film, resulting in poor resolution of the dry film, and a good resist pattern cannot be obtained.

[0018] In the present application, the preparation method of the 2,2'-di(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator represented by formula (I) comprises the following steps:

[0019] (1) The raw material a and the raw material b are reacted in a solvent containing a catalyst to obtain an intermediate A;

[0020] (2) The intermediate A and the raw material c are reacted in glacial acetic acid to obtain an intermediate B;

[0021] (3) The intermediate B is reacted in a solvent containing an oxidizing agent to obtain a product C.

[0022] The reaction equation is shown as follows:

[0023] HABI initiators are a kind of photoinitiators well known in the field of photoresists, which can be prepared by oxidative coupling of substituted triphenyl imidazole compounds. The oxidizing agents used in the preparation can be exemplified by sodium hypochlorite, potassium ferricyanide, etc., the phase transfer catalysts used can be exemplified by tetrabutylammonium bromide, benzyltriethylammonium chloride, crown ether (15-crown-5, 18-crown-6), polyethylene glycol, etc., and the specific preparation process can refer to the description in the prior art such as US3784557, US4622286 and US4311783 (herein incorporated by reference in their entirety).

[0024] In a second aspect, the present application provides a photosensitive resin composition comprising the following components:

[0025] (A) The 2,2'-di(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator as described above;

[0026] (B) An alkali-soluble polymer;

[0027] (C) A compound having an olefinic unsaturated double bond.

[0028] The content of the 2,2'-bis(2-alkyloxyphenyl)-4,4',5,5'-tetraphenyl-2H-benzotriazole photoinitiator is preferably 1 to 10 parts by mass, for example, 1 part by mass, 2 parts by mass, 3 parts by mass, 4 parts by mass, 5 parts by mass, 6 parts by mass, 7 parts by mass, 8 parts by mass, 9 parts by mass, or 10 parts by mass, in 100 parts by mass of the photosensitive resin composition. Within this content range, the 2,2'-bis(2-alkyloxyphenyl)-4,4',5,5'-tetraphenyl-2H-benzotriazole photoinitiator exhibits excellent photosensitivity and resolution, and enables good resist patterns to be obtained.

[0029] Alkali-soluble polymer (B)

[0030] The alkali-soluble polymer can impart film-forming properties to the photosensitive resin composition. As the alkali-soluble polymer, any polymer having such properties can be used without particular limitation.

[0031] Illustratively, the alkali-soluble polymer that can be used can be a (meth)acrylic polymer, a styrene polymer, an epoxy polymer, an aliphatic polyurethane (meth)acrylate polymer, an aromatic polyurethane (meth)acrylate polymer, an amide resin, an amide epoxy resin, an alkyd resin, a phenolic resin, and the like.

[0032] Further, the alkali-soluble polymer can be obtained by radical polymerization of a polymerizable monomer. As the polymerizable monomer, the following can be exemplified: a polymerizable styrene derivative substituted at the α-position or on the aromatic ring, such as styrene, vinyltoluene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, p-chlorostyrene; an acrylamide derivative, such as acrylamide, diacetone acrylamide; an ether derivative of a vinyl alcohol, such as propylene oxide; a (meth)acrylic acid derivative, such as (meth)acrylic acid, α-bromo(meth)acrylic acid, α-chloro(meth)acrylic acid, β-furyl(meth)acrylic acid, β-styryl(meth)acrylic acid; a (meth)acrylate compound, such as (meth)acrylic acid alkyl ester, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate; a maleic acid monoester, such as maleic acid, maleic anhydride, maleic acid monomethyl ester, maleic acid monoethyl ester, maleic acid monoiso-propyl ester; fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, propenoic acid, N-vinylcaprolactam; N-vinylpyrrolidone. These polymerizable monomers can be used alone or in combination of two or more.

[0033] Further, from the viewpoint of alkali developability and adhesion, it is preferable to use a carboxyl group-containing alkali-soluble polymer. The alkali-soluble polymer having a carboxyl group can be an acrylic resin containing (meth)acrylic acid as a monomer unit, which introduces a carboxyl group by using (meth)acrylic acid as a monomer unit; can be a copolymer further containing (meth)acrylic acid alkyl ester as a monomer unit in addition to (meth)acrylic acid; or can be a copolymer further containing a polymerizable monomer other than (meth)acrylic acid and (meth)acrylic acid alkyl ester, such as a monomer having an ethylenic unsaturated group, as a monomer component.

[0034] Further, the carboxyl group-containing alkali-soluble polymer can be obtained by radical polymerization of a polymerizable monomer having a carboxyl group and other polymerizable monomers, and particularly a (meth)acrylate polymer copolymerized from a (meth)acrylate, an ethylenic unsaturated carboxylic acid, and other copolymerizable monomers.

[0035] The (meth)acrylate can be methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, furfuryl (meth)acrylate, glycidyl (meth)acrylate, and the like. These (meth)acrylates can be used alone or in combination of two or more.

[0036] The ethylenically unsaturated carboxylic acid can be acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and particularly preferably acrylic acid and methacrylic acid. These ethylenically unsaturated carboxylic acids can be used alone or in combination of two or more.

[0037] The other copolymerizable monomer can be (meth)acrylamide, n-butyl (meth)acrylate, styrene, vinyl naphthalene, (meth)acrylonitrile, vinyl acetate, vinyl cyclohexane, and the like. These other copolymerizable monomers can be used alone or in combination of two or more.

[0038] The alkali-soluble polymers can be used alone or in combination of two or more. As the alkali-soluble polymers used in combination of two or more, two or more alkali-soluble polymers composed of different copolymerization components, two or more alkali-soluble polymers having different weight average molecular weights, two or more alkali-soluble polymers having different dispersities, and the like can be exemplified.

[0039] In the photosensitive resin composition of the present application, the weight average molecular weight of the alkali-soluble polymer is not particularly limited and should be adapted to the specific application environment. From the comprehensive consideration of mechanical strength and alkali developability, the weight average molecular weight is preferably 15,000 to 200,000 (e.g., 15,000, 18,000, 20,000, 30,000, 50,000, 80,000, 100,000, 130,000, 150,000, 180,000, or 200,000), more preferably 30,000 to 150,000, and particularly preferably 30,000 to 120,000. When the weight average molecular weight is greater than 15,000, the post-exposure resistance to the developing solution tends to be further improved, and when the weight average molecular weight is less than 200,000, the developing time tends to be made shorter, and the compatibility with other components such as a photoinitiator can be maintained. The weight average molecular weight of the alkali-soluble polymer is measured by gel permeation chromatography (GPC) and is obtained by conversion using a standard curve of standard polystyrene.

[0040] Further, from the viewpoint of good alkali developability, the acid value of the alkali-soluble polymer is preferably 50 to 300 mgKOH / g, e.g., 50 mgKOH / g, 80 mgKOH / g, 100 mgKOH / g, 130 mgKOH / g, 150 mgKOH / g, 180 mgKOH / g, 200 mgKOH / g, 250 mgKOH / g, mgKOH / g, 280 mgKOH / g, or 300 mgKOH / g, more preferably 50 to 250 mgKOH / g, further preferably 70 to 250 mgKOH / g, and particularly preferably 100 to 250 mgKOH / g. When the acid value of the alkali-soluble resin is less than 50 mgKOH / g, it is difficult to ensure sufficient developing speed, and when it exceeds 300 mgKOH / g, the adhesion decreases, pattern short-circuiting tends to occur, and problems such as a decrease in storage stability of the composition and an increase in viscosity tend to arise.

[0041] The molecular weight distribution [weight average molecular weight (Mw) / number average molecular weight (Mn)] of the alkali-soluble resin is preferably 1.5 to 6.0, and particularly preferably 1.8 to 3.7. When the molecular weight distribution is within the range, the developability is excellent.

[0042] The content of the alkali-soluble polymer in the composition is preferably 20 to 70 parts by mass, for example, 20 parts by mass, 25 parts by mass, 30 parts by mass, 35 parts by mass, 40 parts by mass, 45 parts by mass, 50 parts by mass, 55 parts by mass, 58 parts by mass, 60 parts by mass, 65 parts by mass, 68 parts by mass, or 70 parts by mass, more preferably 45 to 65 parts by mass, in 100 parts by mass of the photosensitive resin composition. When the content of the alkali-soluble polymer is 20 parts by mass or more, the durability of the photosensitive resin composition to plating treatment, etching treatment, and the like can be ensured to be improved, and when the content is 70 parts by mass or less, the sensitivity of the photosensitive resin composition can be improved favorably.

[0043] Compound (C) having an ethylenically unsaturated double bond

[0044] The compound having an ethylenically unsaturated double bond can promote the film formation of the photosensitive resin composition.

[0045] The compound having an ethylenically unsaturated double bond is not particularly limited, and a photopolymerizable compound having at least one ethylenically unsaturated bond in the molecule can be used. Exemplarily, compounds obtained by reacting α,β-unsaturated carboxylic acid with a polyol, bisphenol A-based (meth)acrylate compounds, compounds obtained by reacting α,β-unsaturated carboxylic acid with a glycidyl group-containing compound, urethane monomers such as (meth)acrylate compounds having an urethane bond in the molecule, nonylphenoxy polyethyleneoxy acrylate, γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl phthalate, β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate, phthalic acid-based compounds, alkyl (meth)acrylate, and the like can be listed. These compounds can be used alone or in combination of two or more.

[0046] As the compound obtained by reacting the above α,β-unsaturated carboxylic acid with a polyhydric alcohol, there can be mentioned polyethylene glycol di(meth)acrylate having an ethylene group number of 2 to 14, polypropylene glycol di(meth)acrylate having a propylene group number of 2 to 14, polyethylene polypropylene glycol di(meth)acrylate having an ethylene group number of 2 to 14 and a propylene group number of 2 to 14, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO and PO-modified trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, polypropylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, tripropylene glycol di(meth)acrylate, and the like. These compounds can be used alone or in combination of two or more. Here, "EO" indicates ethylene oxide, and the compound modified with EO means a compound having a block structure of an oxyethylene group. "PO" indicates propylene oxide, and the compound modified with PO means a compound having a block structure of an oxypropylene group.

[0047] As the above-mentioned bisphenol A type (meth)acrylate compound, there can be mentioned 2,2-bis{4-[(meth)acryloyloxy polyethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy polypropoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy polybutoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy polyethoxypolypropoxy]phenyl}propane, and the like. As the above-mentioned 2,2-bis{4-[(meth)acryloyloxy polyethoxy]phenyl}propane, there can be mentioned 2,2-bis{4-[(meth)acryloyloxy diethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy triethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy tetraethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy pentaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy hexaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy heptaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy octaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy nonaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy decaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy undecaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy dodecaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy tridecaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy tetradecaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy pentadecaethoxy]phenyl}propane, 2,2-bis{4-[(meth)acryloyloxy hexadecaethoxy]phenyl}propane, and the like. The number of ethylene oxide groups in one molecule of the above-mentioned 2,2-bis{4-[(meth)acryloyloxy polyethoxy]phenyl}propane is preferably 4 to 20, more preferably 8 to 15. These compounds can be used alone or in combination of two or more.

[0048] As the above-mentioned (meth)acrylate compound having urethane bond in the molecule, there can be mentioned an addition reaction product of a (meth)acrylic monomer having OH group at β position and a diisocyanate compound (isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, 1,6-hexamethylene diisocyanate, and the like), tris[(meth)acryloyloxy tetraethylene glycol isocyanate] hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, PO-modified urethane di(meth)acrylate, EO, PO-modified urethane di(meth)acrylate, and the like. These compounds can be used alone or in combination of two or more.

[0049] Examples of the aforementioned nonylphenoxy polyethylene acrylates include: nonylphenoxy tetraethylene acrylate, nonylphenoxy pentaethylene acrylate, nonylphenoxy hexaethylene acrylate, nonylphenoxy heptaethylene acrylate, nonylphenoxy octaethylene acrylate, nonylphenoxy nonaethylene acrylate, nonylphenoxy decaethylene acrylate, and nonylphenoxy undecaethylene acrylate. These compounds can be used alone or in combination of two or more.

[0050] Examples of the aforementioned phthalic acid compounds include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate and β-hydroxyalkyl-β'-(meth)acryloyloxyalkyl phthalate. These compounds can be used alone or in combination of two or more.

[0051] Examples of the aforementioned alkyl methacrylates include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, isobornyl methacrylate, hydroxymethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and methyl methacrylate- 2-Hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, benzyl methacrylate, pentyl methacrylate, tetrahydrofurfuryl methacrylate, isooctyl methacrylate, ethoxylated nonylphenol methacrylate, propylene glycol polypropylene ether dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, ethoxylated polytetrahydrofurandiol dimethacrylate, ethoxylated polypropylene glycol dimethacrylate, etc. Preferably, methyl methacrylate, ethyl methacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, ethoxylated pentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate, and dipentaerythritol hexaacrylate are used. These compounds can be used alone or in combination of two or more.

[0052] From the viewpoint of improving resolution, plating resistance, and adhesion, the compound having an ethylenically unsaturated double bond is preferably a bisphenol A type (meth)acrylate compound and a (meth)acrylate compound having an urethane bond in the molecule. From the viewpoint of being able to improve sensitivity and resolution, the bisphenol A type (meth)acrylate compound is preferred. As commercially available products of the bisphenol A type (meth)acrylate compound, exemplified are 2,2-bis{4-[(meth)acryloyloxy polyethoxy]phenyl}propane (manufactured by Shin-Nakamura Chemical Co., Ltd., BPE-200), 2,2-bis{4-[(meth)acryloyloxy polypropoxy]phenyl}propane (manufactured by Shin-Nakamura Chemical Co., Ltd., BPE-5000; manufactured by Hitachi Chemical Co., Ltd., FA-321M), 2,2-bis{4-[(meth)acryloyloxy polybutoxy]phenyl}propane (Shin-Nakamura Chemical Co., Ltd., BPE-1300), and the like.

[0053] The content of the compound having an ethylenically unsaturated double bond (C) is preferably 20 to 60 parts by mass, for example, 20 parts by mass, 25 parts by mass, 30 parts by mass, 35 parts by mass, 40 parts by mass, 45 parts by mass, or 50 parts by mass, and more preferably 30 to 50 parts by mass, in 100 parts by mass of the photosensitive resin composition. When the content of the compound having an ethylenically unsaturated double bond is 20 parts by mass or more, the sensitivity and resolution of the photosensitive resin composition are further improved. When the content thereof is 60 parts by mass or less, the photosensitive resin composition is more easily film-formed, and the durability to etching treatment is further improved.

[0054] Other optional auxiliary agent (D)

[0055] In addition to the above-described components, optionally, the photosensitive resin composition of the present application can contain other auxiliary agents as needed, in an appropriate amount. Exemplarily, the auxiliary agent can include at least one of other photoinitiators and / or sensitizers, hydrogen donors, organic solvents, dyes, pigments, photochromic agents, fillers, plasticizers, stabilizers, coating aids, release promoters, and the like.

[0056] The other photoinitiators and / or sensitizers can include, but are not limited to, bisimidazoles, aromatic ketones, anthraquinones, benzoin and benzoin alkyl ethers, oxime esters, triazines, coumarins, thioxanthones, acridines, and other photoinitiators known to those skilled in the art.

[0057] Exemplary bis-imidazoles include: 2,2'-di(o-chlorophenyl)-4,4',5,5'- tetraphenyl-bis-imidazole, 2,2',5-tris(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)- 4',5'-diphenyl-1,1'-bis-imidazole, 2,2',5-tris(2-fluorophenyl)-4-(3,4- dimethoxyphenyl)-4',5'-diphenyl-bis-imidazole, 2,2'-di(2,4-dichlorophenyl)-4,4',5,5'- tetraphenyl-bis-imidazole, 2,2'-di(2-fluorophenyl)-4-(o-chlorophenyl)-5-(3,4- dimethoxyphenyl)-4',5'-diphenyl-bis-imidazole, 2,2'-di(2-fluorophenyl)-4,4',5,5'- tetraphenyl-bis-imidazole, 2,2'-di(2-methoxyphenyl)-4,4',5,5'-tetraphenyl-bis- imidazole, 2,2'-di(2-chloro-5-nitrophenyl)-4,4'-di(3,4-dimethoxyphenyl)-5,5'- di(o-chlorophenyl)-bis-imidazole, 2,2'-di(2-chloro-5-nitrophenyl)-4-(3,4- dimethoxyphenyl)-5-(o-chlorophenyl)-4',5'-diphenyl-bis-imidazole, 2,2'-di(2,4- dichlorophenyl)-4,4'-di(3,4-dimethoxyphenyl)-5,5'-di(o-chlorophenyl)-bis- imidazole, 2-(2,4-dichlorophenyl)-4-(3,4-dimethoxyphenyl)-2',5-di(o- chlorophenyl)-4',5'-diphenyl-bis-imidazole, 2-(2,4-dichlorophenyl)-2'-(o- chlorophenyl)-4,4',5,5'-tetraphenyl-bis-imidazole, 2,2'-di(2,4-dichlorophenyl)-4,4',5,5'- tetraphenyl-bis-imidazole, and the like. These bis-imidazoles can be used alone or in combination of two or more.

[0058] Exemplarily, the aromatic ketone compounds include: acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, benzophenone, 4-benzoyldiphenyl sulfide, 4-benzoyl-4'-methyl diphenyl sulfide, 4-benzoyl-4'-ethyl diphenyl sulfide, 4-benzoyl-4'-propyl diphenyl sulfide, 4,4'-bis(diethylamino)benzophenone, 4-p-toluenethiobenzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(methyl, ethylamino)benzophenone, acetophenone dimethyl ketal, benzil dimethyl ketal, α,α'-dimethyl benzil ketal, α,α'-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl benzophenone, 2-hydroxy-2-methyl-1-p-hydroxyethyloxyphenylpropanone, 2-methyl 1-(4-methylthiophenyl)-2-morpholinopropanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, 2,4,6-trimethylbenzoyl)diphenyl phosphine oxide, 2-hydroxy-1-{3-[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-1,1,3-trimethyl-inden-5-yl}-2-methylpropanone, 2-hydroxy-1-{1-[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-1,3,3-trimethyl-inden-5-yl}-2-methylpropanone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl-(2-hydroxy-2-propyl) ketone, and the like. These aromatic ketone compounds can be used alone or in combination of two or more.

[0059] Exemplarily, the anthraquinone compounds include: 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 2,3-dimethylanthraquinone, 2-ethylanthracene-9,10-diethyl, 1,2,3-trimethylanthracene-9,10-dioctyl, 2-ethylanthracene-9,10-di(4-chlorobutyl methyl), 2-{3-[(3-ethyloxetane-3-yl)methoxy]-3-oxopropyl}anthracene-9,10-diethyl, 9,10-dibutoxyanthracene, 9,10-diethoxy-2-ethylanthracene, 9,10-bis(3-chloropropoxy)anthracene, 9,10-bis(2-hydroxyethanethio)anthracene, 9,10-bis(3-hydroxy-1-propanethio)anthracene, and the like. These anthraquinone compounds can be used alone or in combination of two or more.

[0060] Exemplarily, the benzoin and benzoin alkyl ether compounds include benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether and the like. These benzoin and benzoin alkyl ether compounds can be used alone or in combination of two or more.

[0061] Exemplary oxime ester compounds can include: 1 -(4-phenylthiophenyl)-n-octane- 1,2-dione-2-benzoic acid oxime ester, 1 -[6-(2-methylbenzoyl)-9-ethylcarbazol-3-yl]- ethan-1 -one-acetic acid oxime ester, 1 -[6-(2-methylbenzoyl)-9-ethylcarbazol-3-yl]- butan-1 -one-acetic acid oxime ester, 1 -[6-(2-methylbenzoyl)-9-ethylcarbazol-3-yl]- propan-1 -one-acetic acid oxime ester, 1 -[6-(2-methylbenzoyl)-9-ethylcarbazol-3-yl]-1 - cyclohexyl-methan-1 -one-acetic acid oxime ester, 1 -[6-(2-methylbenzoyl)-9-ethylcarbazol- 3-yl]-(3-cyclopentyl)-propan-1 -one-acetic acid oxime ester, 1 -(4-phenylthiophenyl)-(3- cyclopentyl)-propan-1,2-dione-2-benzoic acid oxime ester, 1 -(4-phenylthiophenyl)-(3- cyclohexyl)-propan-1,2-dione-2-cyclohexyl carboxylic acid oxime ester, 1 -[6-(2- methylbenzoyl)-9-ethylcarbazol-3-yl]-(3-cyclopentyl)-propan-1,2-dione-2-acetic acid oxime ester, 1 -(6-o-methylbenzoyl-9-ethylcarbazol-3-yl)-(3-cyclopentyl)-propan-1,2- dione-2-benzoic acid oxime ester, 1 -(4-benzoyldiphenyl sulfide)-(3-cyclopentylpropanone)- 1 -oxime acetic acid ester, 1 -(6-o-methylbenzoyl-9-ethylcarbazol-3-yl)-(3-cyclopentylpropanone)- 1 -oxime cyclohexyl carboxylic acid ester, 1 -(4-benzoyldiphenyl sulfide)-3- cyclopentylpropanone)-1 -oxime cyclohexyl carboxylic acid ester, 1 -(6-o-methylbenzoyl-9- ethylcarbazol-3-yl)-(3-cyclopentyl)-propan-1,2-dione-2-o-methylbenzoic acid oxime ester, 1 -(4-phenylthiophenyl)-(3-cyclopentyl)-propan-1,2-dione-2-cyclohexyl carboxylic acid oxime ester, 1 -(4-thiophenecarbonyl-diphenyl sulfide-4'-yl)-3-cyclopentyl-propan-1 - one-acetic acid oxime ester, 1 -(4-benzoyldiphenyl sulfide)-(3-cyclopentyl)-propan-1,2- dione-2-oxime acetic acid ester, 1 -(6-nitro-9-ethylcarbazol-3-yl)-3-cyclohexyl-propan-1 - one-acetic acid oxime ester, 1 -(6-o-methylbenzoyl-9-ethylcarbazol-3-yl)-3-cyclohexyl- propan-1 -one-acetic acid oxime ester, 1 -(6-thiophenecarbonyl-9-ethylcarbazol-3-yl)-(3- cyclohexylpropanone)-1 -oxime acetic acid ester, 1 -(6-furancarbonyl-9-ethylcarbazol-3- yl)-(3-cyclopentylpropanone)-1 -oxime acetic acid ester, 1,4-diphenylpropan-1,3-dione-2- acetic acid oxime ester, 1 -(6-furoyl-9-ethylcarbazol-3-yl)-(3-cyclohexyl)-propan-1,2-dione- 2-acetic acid oxime ester, 1 -(4-phenylthiophenyl)-(3-cyclohexyl)-propan-1,2-diketone-2-acetoxime, 1-(6-furobenzoyl-9-ethylcarbazol-3-yl)-(3-cyclohexylpropan)-1-oxime acetic acid ester, 1-(4-phenylthiophenyl)-(3-cyclohexyl)-propane-1,2-diketone-3-benzoic acid oxime ester, 1-(6-thiophenecarboxyl-9-ethylcarbazol-3-yl)-(3-cyclohexyl)-propane-1,2-diketone-2-acetoxime ester, 2-[(benzoyloxy)imino]-1-phenylpropane-1-one, 1-phenyl-1,2-propanedione-2-(oxoacetyl)oxime, 1-(4-phenylthiophenyl)-2-(2-methylphenyl)-ethane-1,2-diketone-2-acetoxime ester, 1-(9,9-dibutyl-7-nitrofluorene-2-yl)-3-cyclohexyl-propane-1-one-acetoxime ester, 1-{4-[4-(thiophene-2-carboxyl)phenylthio]phenyl}-3-cyclopentylpropane-1,2-diketone-2-acetoxime ester, 1-[9,9-dibutyl-2-yl]-3-cyclohexylpropylpropane-1,2-diketone-2-acetoxime ester, 1-[6-(2-benzoyloxyimino)-3-cyclohexylpropyl-9-ethylcarbazol-3-yl]octane-1,2-diketone-2-benzoic acid oxime ester, 1-(7-nitro-9,9-diallylfluorene-2-yl)-1-(2-methylphenyl)methanone-acetoxime ester, 1-[6-(2-methylbenzoyl)-9-ethylcarbazol-3-yl]-3-cyclopentyl-propane-1-one-benzoic acid oxime ester, 1-[7-(2-methylbenzoyl)-9,9-dibutylfluorene-2-yl]-3-cyclohexylpropane-1,2-diketone-2-acetoxime ester, 1-[6-(furan-2-carboxyl)-9-ethylcarbazol-3-yl]-3-cyclohexylpropane-1,2-diketone-2-ethoxycarbonyloxime ester, and the like. These oxime ester compounds can be used alone or in combination of two or more.

[0062] Exemplary triazines include 2-(4-ethylphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(3,4-methylenedioxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 3-{4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]thiophenyl}propionic acid, 1,1,1,3,3,3-hexafluoroisopropyl-3-{4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]thiophenyl}propionate, ethyl-2-{4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]thiophenyl}acetate, 2-ethoxyethyl-2-{4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]thiophenyl}acetate, cyclohexyl-2-{4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]thiophenyl}acetate, benzyl-2-{4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]thiophenyl}acetate, 3-{chloro-4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]thiophenyl}propionic acid, 3-{4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]thiophenyl}propionamide, 2,4-bis(trichloromethyl)-6-p-methoxystyryl-s-triazine, 2,4-bis(trichloromethyl)-6-(1-p-dimethylaminophenyl)-1,3-butadienyl-s-triazine, 2-trichloromethyl-4-amino-6-p-methoxystyryl-s-triazine, and the like. These triazines can be used alone or in combination of two or more.

[0063] Exemplary coumarins include 3,3'-carbonylbis(7-diethylaminocoumarin), 3-benzoyl-7-diethylaminocoumarin, 3,3'-carbonylbis(7-methoxycoumarin), 7-diethylamino-4-methylcoumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 7-(diethylamino)-4-methyl-2H-1-benzopyran-2-one [7-(diethylamino)-4-methylcoumarin], 3-benzoyl-7-methoxycoumarin, and the like. These coumarins can be used alone or in combination of two or more.

[0064] Exemplary thioxanthones include thioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, 1-chloro-4-propoxythioxanthone, isopropylthioxanthone, diisopropylthioxanthone, and the like. These thioxanthones can be used alone or in combination of two or more.

[0065] Exemplarily, the acridine compounds include: 9-phenylacridine, 9-p-methylphenylacridine, 9-m-methylphenylacridine, 9-o-chlorophenylacridine, 9-o-fluorophenylacridine, 1,7-bis(9-acridinyl)heptane, 9-ethylacridine, 9-(4-bromophenyl)acridine, 9-(3-chlorophenyl)acridine, 1,7-bis(9-acridinyl)heptane, 1,5-bis(9-acridinyl)pentane, 1,3-bis(9-acridinyl)propane, and the like. These acridine compounds can be used alone or in combination of two or more.

[0066] The photosensitive resin composition of the present application further includes a hydrogen donor to improve photosensitivity. The bis-imidazole compound is cleaved upon light irradiation, and the generated mono-imidazole radical is bulky and has a steric hindrance effect, so that it is difficult to initiate polymerization of monomers alone. However, if the mono-imidazole radical is used in combination with a hydrogen donor, the mono-imidazole radical easily abstracts a labile hydrogen from the hydrogen donor to generate a new active radical, which in turn initiates polymerization of monomers.

[0067] The hydrogen donor is not particularly limited as long as it has the above-mentioned properties, and can include, but is not limited to, amine compounds, carboxylic acid compounds, organic sulfur compounds containing a mercapto group, alcohol compounds, and the like. These compounds can be used alone or in combination of two or more thereof.

[0068] The amine compounds are not particularly limited, and can include, but are not limited to, aliphatic amine compounds such as triethanolamine, methyldiethanolamine, triisopropanolamine, and the like; aromatic amine compounds such as methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isopentyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, N,N-dimethyl-p-toluidine, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, and the like.

[0069] The carboxylic acid compounds are not particularly limited, and can include, but are not limited to, aromatic heteroacetic acid, phenylthioacetic acid, methylphenylthioacetic acid, ethylphenylthioacetic acid, methylethylphenylthioacetic acid, dimethylphenylthioacetic acid, methoxyphenylthioacetic acid, dimethoxyphenylthioacetic acid, chlorophenylthioacetic acid, dichlorophenylthioacetic acid, N-phenylglycine, phenoxyacetic acid, naphthylthioacetic acid, N-naphthylglycine, naphthoxyacetic acid, and the like.

[0070] The organic sulfur compounds containing mercapto groups are not particularly limited and can include, but are not limited to, 2-mercaptobenzothiazole (MBO), 2- mercaptobenzimidazole (MBI), dodecyl mercaptan, ethylene glycol bis(3- mercaptobutyrate), 1,2-propanediol bis(3-mercaptobutyrate), diethylene glycol bis(3- mercaptobutyrate), butylene glycol bis(3-mercaptobutyrate), octylene glycol bis(3- mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetra(3- mercaptobutyrate), dipentaerythritol hexa(3-mercaptobutyrate), ethylene glycol bis(2- mercaptopropionate), propylene glycol bis(2-meraptopropionate), diethylene glycol bis(2- mercaptopropionate), butylene glycol bis(2-meraptopropionate), octylene glycol bis(2- mercaptopropionate), trimethylolpropane tris(2-meraptopropionate), pentaerythritol tetra(3- mercaptopropionate), dipentaerythritol hexa(2-meraptopropionate), ethylene glycol bis(3- mercaptocaprylate), 1,2-propanediol bis(3-mercaptocaprylate), diethylene glycol bis(3- mercaptocaprylate), butylene glycol bis(3-mercaptocaprylate), octylene glycol bis(3- mercaptocaprylate), trimethylolpropane tris(3-mercaptocaprylate), pentaerythritol tetra(3- mercaptocaprylate), dipentaerythritol hexa(3-mercaptocaprylate), ethylene glycol bis(2- mercaptocaprylate), 1,2-propanediol bis(2-mercaptocaprylate), diethylene glycol bis(2- mercaptocaprylate), butylene glycol bis(2-mercaptocaprylate), octylene glycol bis(2- mercaptocaprylate), trimethylolpropane tris(2-mercaptocaprylate), pentaerythritol tetra(2- mercaptocaprylate), dipentaerythritol hexa(2-mercaptocaprylate), ethylene glycol bis(4- mercaptobutyrate), 1,2-propanediol bis(4-mercaptobutyrate), diethylene glycol bis(4- mercaptobutyrate), butylene glycol bis(4-mercaptobutyrate), octylene glycol bis(4- mercaptobutyrate), trimethylolpropane tris(4-mercaptobutyrate), pentaerythritol tetra(4- mercaptobutyrate), dipentaerythritol hexa(4-mercaptobutyrate), ethylene glycol bis(3- mercaptobutyrate), 1,2-propanediol bis(3-mercaptobutyrate), diethylene glycol bis(3- mercaptobutyrate), butylene glycol bis(3-mercaptobutyrate), octylene glycol bis(3- mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetra(3- mercaptobutyrate), dipentaerythritol hexa(3-mercaptobutyrate), and the like aliphatic secondary multifunctional mercaptan compounds; aromatic secondary multifunctional mercaptan compounds such as phthalic acid di(1-mercaptoethyl ester), phthalic acid di(2- mercaptopropyl ester), phthalic acid di(3-mercaptobutyl ester), phthalic acid di(3- mercaptocapryl ester), and the like.

[0071] The alcohol compound is not particularly limited, and can include, but is not limited to, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, neopentyl alcohol, n-hexanol, cyclohexanol, ethylene glycol, 1,2-propanediol, 1,2,3-propanetriol, benzyl alcohol, phenethyl alcohol, and the like.

[0072] The organic solvent can be any solvent that can dissolve the aforementioned components, and can be exemplified by glycol ether-based solvents, alcohol-based solvents, ester-based solvents, ketone-based solvents, amide-based solvents, chlorine-containing solvents, and the like, and is preferably selected in consideration of the solubility of the colorant and the alkali-soluble polymer, coatability, safety, and the like. In one embodiment, the organic solvent can be ethyl cellosolve (ethylene glycol monoethyl ether), methyl cellosolve (ethylene glycol monomethyl ether), butyl cellosolve (ethylene glycol monobutyl ether), methyl methoxy butanol (3-methyl-3-methoxy butanol), butyl carbitol (diethylene glycol monobutyl ether), ethylene glycol monoethyl ether acetate, ethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether (1-methoxy-2-propanol), propylene glycol monoethyl ether (1-ethoxy-2-propanol), propylene glycol monoethyl ether acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, acetyl cellosolve (ethylene glycol monomethyl ether acetate), methoxy butyl acetate (3-methoxy butyl acetate), 3-methyl-3-methoxy butyl acetate, ethyl 3-ethoxypropionate (EEP), methyl lactate, ethyl lactate, propyl lactate, butyl lactate, 2-butanone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, cyclopentanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), isophorone (3,5,5-trimethyl-2-cyclohexen-1-one), diisobutyl ketone (2,6-dimethyl-4-heptanone), N-methyl pyrrolidone (4-methyl aminolactam or NMP), methanol, ethanol, isopropyl alcohol, n-propanol, isobutyl alcohol, n-butyl alcohol, and the like. These solvents can be used alone or in combination of two or more thereof.

[0073] Exemplarily, the dyes, pigments, and photochromic agents include: tris(4-dimethylaminophenyl)methane, tris(4-dimethylamino-2-methylphenyl)methane, fluoran dye, toluenesulfonic acid monohydrate, basic fuchsin, phthalocyanine-based pigments such as phthalocyanine green and phthalocyanine blue, auramine base, pararosaniline, crystal violet, methyl orange, nile blue 2B, victoria blue, malachite green, adamant green, basic blue 20, brilliant green, eosin, ethyl violet, erythrosin sodium salt B, methyl green, phenolphthalein, alizarin red S, thymolphthalein, methyl violet 2B, quinaldine red, rose bengal sodium agar, mittaniel yellow, thymolphthalein sulfone, xylenol blue, methyl orange, orange IV, diphenyl picrylhydrazyl, 2,7-dichlorofluorescein, panchrome red, congo red, benzopurpurine 4B, a-naphthyl red, phenazone, methyl violet, victoria pure blue BOH, rhodamine 6G, diphenylamine, dibenzylphenylamine, triphenylamine, diethylphenylamine, di-p-stilbazene, p-toluidine, benzotriazole, methylphenyltriazole, 4,4'-diaminostilbene, o-chloroaniline, white crystal violet, white malachite green, white aniline, white methyl violet, organic pigments such as azo-based pigments, and inorganic pigments such as titanium dioxide. Tris(4-dimethylaminophenyl)methane (i.e., leuco crystal violet, LCV) is preferably used in view of good contrast. These dyes, pigments, and photochromic agents can be used alone or in combination of two or more.

[0074] Exemplarily, the fillers include: silica, alumina, talc, calcium carbonate, barium sulfate, and other fillers (excluding the inorganic pigments described above). The fillers can be used alone or in combination of two or more.

[0075] Exemplarily, the plasticizers include: dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, diallyl phthalate, and other phthalates; triethylene glycol diacetate, tetraethylene glycol diacetate, and other glycol esters; p-toluenesulfonamide, benzene sulfonamide, n-butyl benzene sulfonamide, and other sulfonamides; triphenyl phosphate, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate, 2-naphthyl diphenyl phosphate, cresyl di-2,6-dimethylphenyl phosphate, aromatic condensed phosphate, tris(chloropropyl) phosphate, tris(tribromoneopentyl) phosphate, halogen-containing condensed phosphate, triethylene glycol dioctanoate, triethylene glycol di-2-ethylhexanoate, tetraethylene glycol diheptanoate, diethyl sebacate, dibutyl suberate, tri(2-ethyl ethyl) phosphate, Brij 30 [C 12 H 25 (OCH2CH2)4OH], and Brij 35 [C 12 H 25 (OCH2CH2) 20 OH]. The plasticizers can be used alone or in combination of two or more.

[0076] Exemplarily, the stabilizer includes: hydroquinone, 1,4,4-trimethyl- diazobicyclo(3.2.2)-non-2-ene-2,3-dioxide, 1-phenyl-3-pyrazolidone, p- methoxyphenol, alkyl and aryl substituted hydroquinone and quinone, t- butylcatechol, 1,2,3-benzene triol, copper resinate, naphthylamine, β- naphthol, cuprous chloride, 2,6-di-t-butyl-p-cresol, phenothiazine, pyridine, nitrobenzene, dinitrobenzene, p-toluquinone, and chloranil, etc. The stabilizer can be used alone or in combination of two or more.

[0077] Exemplarily, the coating aid includes: acetone, methanol, methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl ethyl ketone, propylene glycol monomethyl ether acetate, ethyl lactate, cyclohexanone, γ-butyrolactone, dichloromethane, etc. The coating aid can be used alone or in combination of two or more.

[0078] Exemplarily, the peeling promoter includes: benzene sulfonic acid, toluene sulfonic acid, xylene sulfonic acid, phenol sulfonic acid, alkyl benzene sulfonic acid such as methyl, propyl, heptyl, octyl, decyl, dodecyl, etc. The peeling promoter can be used alone or in combination of two or more.

[0079] The content of the other aid is 0-10 parts by mass, for example, 1 part by mass, 2 parts by mass, 3 parts by mass, 4 parts by mass, 5 parts by mass, 6 parts by mass, 7 parts by mass, 8 parts by mass, 9 parts by mass, or 10 parts by mass, preferably 0.5-5 parts by mass, in 100 parts by mass of the photosensitive resin composition.

[0080] <Applications>

[0081] The photosensitive resin composition of the present application can be prepared into a dry film, i.e., a photosensitive resin laminate, and applied to the manufacture of printed circuit boards, protective patterns, conductor patterns, lead frame lines, semiconductor packages, etc., to form the required patterns on different substrates through different processes.

[0082] The photosensitive resin composition of the present application can also be coated onto the corresponding substrates in the corresponding manufacturing steps by a wet film coater, i.e., applied as a wet film to the manufacture of printed circuit boards, protective patterns, conductor patterns, lead frame lines, semiconductor packages, etc., to form the required patterns on different substrates through different processes.

[0083] Dry film applications

[0084] The dry film, i.e., the photosensitive resin laminate of the present application, comprises a photosensitive resin layer formed of a photosensitive resin composition and a support body supporting the photosensitive resin layer.

[0085] In general, the dry film is produced by applying the photosensitive resin composition to a support, drying to form a photosensitive resin layer, and optionally, attaching a cover film (protective layer) as needed. Preferably, the drying conditions are 60 to 100°C for 0.5 to 15 minutes. The thickness of the photosensitive resin layer is preferably 5 to 95 μm, more preferably 10 to 50 μm, and even more preferably 15 to 30 μm. If the thickness of the photosensitive resin layer is less than 5 μm, the insulating properties are poor, and if the thickness of the photosensitive resin layer exceeds 95 μm, the resolution can be poor.

[0086] As the support, specific examples can be various types of plastic films such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, polyethylene, cellulose acetate, polyalkyl methacrylate, methacrylic acid ester copolymer, polyvinyl chloride, polyvinyl alcohol, polycarbonate, polystyrene, cellophane, vinyl chloride copolymer, polyamide, polyimide, ethylene chloride-vinyl acetate copolymer, polytetrafluoroethylene, polytrifluoroethylene, and the like. In addition, a composite material composed of two or more materials can also be used. In one embodiment, polyethylene terephthalate having excellent light transmittance is used. The thickness of the support is preferably 5 to 150 μm, and more preferably 10 to 50 μm.

[0087] The application of the photosensitive resin composition is not particularly limited, and conventional methods such as spray coating, roll coating, spin coating, slit coating, compression coating, curtain coating, dye coating, line coating, blade coating, roller coating, doctor blade coating, spray coating, and dip coating can be used.

[0088] Further, the present application provides the use of the above dry film in the production of a printed circuit board, comprising:

[0089] (1) a lamination step of laminating the photosensitive resin laminate to a copper-clad laminate or a flexible substrate;

[0090] (2) an exposure step of exposing the photosensitive resin layer in the photosensitive resin laminate to active light in an image form to perform photocuring on the exposed portion;

[0091] (3) a development step of removing the unexposed portion of the photosensitive resin layer with a developer to form a protective pattern;

[0092] (4) a conductor pattern formation step of etching or plating the portion of the surface of the copper-clad laminate or the flexible substrate that is not covered by the protective pattern;

[0093] (5) a peeling step of peeling the protective pattern from the copper-clad laminate or the flexible substrate.

[0094] Further, the present application provides the use of the dry film described above in the manufacture of a protective pattern, comprising the lamination process, the exposure process and the development process as described above, except that the photosensitive resin laminate in the lamination process can be laminated on a substrate of various materials.

[0095] Further, the present application provides the use of the dry film described above in the manufacture of a conductor pattern, comprising the lamination process, the exposure process, the development process and the conductor pattern forming process as described above, except that the photosensitive resin laminate in the lamination process is laminated on a metal plate or a metal-coated insulating plate.

[0096] Further, the present application provides the use of the dry film described above in the manufacture of a conductor pattern, comprising the lamination process, the exposure process, the development process and the conductor pattern forming process as described above, except that the photosensitive resin laminate in the lamination process is laminated on a metal plate or a metal-coated insulating plate.

[0097] Further, the present application provides the use of the dry film described above in the manufacture of a conductor pattern, comprising the lamination process, the exposure process, the development process and the conductor pattern forming process as described above, except that the photosensitive resin laminate in the lamination process is laminated on a metal plate or a metal-coated insulating plate.

[0098] Wet film application

[0099] The photosensitive resin composition of the present application can be used in a wet film manner by being directly coated on a substrate for the manufacture of printed circuit boards, protective patterns, conductor patterns, lead frame lines, semiconductor packages and the like.

[0100] Without limitation, the photosensitive resin composition can be coated on a substrate by conventional methods such as roll coating, blade coating, spray coating, dip coating and the like, and after drying, a photosensitive resin layer is formed.

[0101] After the photosensitive resin layer is formed on the substrate, subsequent processes such as the exposure process, the development process, the conductor pattern forming process and the peeling process can be performed in the manner of the dry film application.

[0102] Process steps

[0103] As the light source of the active light, a publicly known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, a gas laser such as an argon laser, a solid laser such as a YAG laser, a semiconductor laser, and a gallium nitride-based blue-violet laser can be used. In addition, a flood lamp for photography, a fluorescent lamp, and the like can be used.

[0104] The kind of the light source of the photosensitive resin composition of the present application is not particularly limited, and the exposure dose is preferably 10 to 1000 mJ / cm 2 .

[0105] In the developing step, the unexposed portion of the photosensitive resin layer is removed with a developer. In the case where the support is present on the photosensitive resin layer, the support is first removed using an automatic peeler or the like, and then the unexposed portion is removed using a developer such as an aqueous alkali solution, a water-based developer, an organic solvent, or the like. Examples of the aqueous alkali solution include a 0.1 to 5 mass% sodium carbonate solution, a 0.1 to 5 mass% potassium carbonate solution, a 0.1 to 5 mass% sodium hydroxide solution, and the like, and the pH is preferably 9 to 11. A surfactant, an antifoaming agent, an organic solvent, or the like can also be added to the aqueous alkali solution. The developing method can be a conventional method such as immersion, spraying, or brushing.

[0106] In the etching treatment, the conductor layer of the circuit-forming substrate that is not covered with the resist pattern is removed by etching using the resist pattern formed on the substrate as a mask, thereby forming a conductor pattern. The method of the etching treatment can be selected depending on the conductor layer to be removed. As the etching solution, for example, a copper oxide solution, an iron oxide solution, an alkali etching solution, a hydrogen peroxide-based etching solution, or the like can be used.

[0107] In the plating treatment, copper, solder, or the like is plated on the insulating board of the circuit-forming substrate that is not covered with the resist pattern formed on the substrate using the resist pattern as a mask. After the plating treatment, the resist pattern is removed, thereby forming a conductor pattern. As the method of the plating treatment, either electroplating treatment or electroless plating treatment can be used, and the electroless plating treatment is preferred. As the electroless plating treatment, for example, copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-throw solder plating, nickel plating such as Watts bath (nickel sulfate-nickel chloride) plating and nickel sulfamate plating, gold plating such as hard gold plating and soft gold plating, and the like can be used.

[0108] The removal of the resist pattern can be performed by peeling with a water solution which is more alkaline than the alkaline water solution used in the developing process. As an example of the strong alkaline water solution, a 1-10 mass% sodium hydroxide water solution can be used.

[0109] Compared with the prior art, the present application has the following beneficial effects:

[0110] The photoinitiator of the present application can enable the photosensitive resin composition to produce a complete resist pattern, and the straightness of the pattern profile is good, while the photosensitive resin composition has good compatibility, can solve the problem of easy precipitation in the developing process, and has good developing property, good hydrophilicity, high resolution, and also good sensitivity, and can meet the requirements of the EU halogen directive.

[0111] Other aspects can be apparent after reading and understanding the detailed description. DETAILED DESCRIPTION

[0112] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application, and should not be regarded as specific limitations of the present application.

[0113] 1. Preparation of 2,2'-bis(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator

[0114] 1.1 Preparation of intermediate A

[0115] Under nitrogen protection, 80.0 g of salicylaldehyde (raw material a), 83.9 g of n-propyl bromide (raw material b), 135.0 g of potassium carbonate, 1.2 g of potassium iodide, 1.2 g of tetrabutylammonium bromide and 500.0 g of acetonitrile were added to a 1L four-necked flask. After the addition was completed, the stirring was started, and the temperature was raised to reflux state, and the reaction was kept for 6h. The sample was controlled by HPLC, and when the content of salicylaldehyde was less than 0.5%, the reaction was considered to be complete, and the temperature was lowered to 25.0°C. After filtration, the filtrate was concentrated under reduced pressure to obtain 101.0 g of intermediate A with a purity of 99.71%.

[0116] The structure of the product intermediate A was confirmed by LCMS, and the mass spectrum analysis obtained a 165 molecular fragment peak by means of the instrument attached software, and the molecular weight of the product was 164, which was consistent with T+1.

[0117] 1.2 Preparation of intermediate B

[0118] Under nitrogen protection, 60.0 g of benzoyl, 51.5 g of intermediate A, 66.1 g of ammonium acetate and 560.0 g of acetic acid were added into a 1 L four-necked flask. After the addition was completed, the stirring was started, and the temperature was raised to reflux, and the reaction was kept for 10 h. The sample was controlled by HPLC, and when the benzoyl was less than 1.0%, the reaction was considered to be complete, and the temperature was lowered to 30.0°C. Then, 300.0 g of pure water was added dropwise into the flask, and after a large amount of solid was precipitated, filtration, washing and drying were performed to obtain the crude intermediate B with a purity of 96.41%. The crude product was put into a four-necked flask, 3 times the amount of methanol (mass ratio) was added, the stirring was started, the temperature was raised to 50.0°C, and after the stirring was kept for 2 h, the temperature was lowered to 25.0±2.0°C, and then filtration, washing and drying were performed to obtain 90.1 g of intermediate B with a purity of 99.03%.

[0119] The structure of the product intermediate A was confirmed by LCMS, and the mass spectrum analysis was performed by using the software attached to the instrument to obtain a 355 molecular fragment peak, and the molecular weight of the product was 354, which was consistent with T+1.

[0120] The structure of the product intermediate B was further confirmed by nuclear magnetic resonance, and the data were as follows:

[0121] 1 H NMR (400 MHz, DMSO-d6) 13.60 (s, 1H), 7.80 (d, 1H), 7.53-7.48 (m, 7H), 7.28-7.16 (m, 6H), 4.05 (dd, 2H), 1.83-1.68 (m, 2H), 1.05-1.02 (m, 3H) ppm.

[0122] 1.3 Preparation of product A1

[0123] Under nitrogen protection, 60.0 g of benzoyl, 51.5 g of intermediate A, 66.1 g of ammonium acetate and 560.0 g of acetic acid were added into a 1 L four-necked flask. After the addition was completed, the stirring was started, and the temperature was raised to reflux, and the reaction was kept for 10 h. The sample was controlled by HPLC, and when the benzoyl was less than 1.0%, the reaction was considered to be complete, and the temperature was lowered to 30.0°C. Then, 300.0 g of pure water was added dropwise into the flask, and after a large amount of solid was precipitated, filtration, washing and drying were performed to obtain the crude intermediate B with a purity of 96.41%. The crude product was put into a four-necked flask, 3 times the amount of methanol (mass ratio) was added, the stirring was started, the temperature was raised to 50.0°C, and after the stirring was kept for 2 h, the temperature was lowered to 25.0±2.0°C, and then filtration, washing and drying were performed to obtain 90.1 g of intermediate B with a purity of 99.03%.

[0124] The structure of product A1 was confirmed by LCMS, and mass spectrometry analysis was performed by using the software attached to the instrument to obtain a molecular fragment peak of 707, and the molecular weight of the product was 706, which was consistent with T+1.

[0125] 1.4 Preparation of products A2 to A10

[0126] Referring to the synthesis method of product A1, different halogenated alkanes were used to replace raw material b, i.e. n-bromopropane, to prepare products A2 to A10, respectively. The analysis of each product is shown in Table 1 below.

[0127] Table 1

[0128] 1.5 Preparation of comparative products A11 to A14

[0129] Referring to the synthesis method of product A1, different halogenated alkanes were used to replace raw material b, i.e. n-bromopropane, to prepare comparative products A11 to A14, respectively. The analysis of each product is shown in Table 2 below.

[0130] Table 2

[0131] 2. Preparation of a photosensitive resin composition

[0132] Referring to the formulation shown in Table 3, the components were mixed uniformly to prepare a photosensitive resin composition. Unless otherwise specified, the parts shown in Table 3 are mass parts.

[0133] Table 3

[0134] The meanings of the component codes in Table 3 are shown in Table 4.

[0135] Table 4

[0136] Preparation of alkali-soluble polymer B: Under a nitrogen atmosphere, a flask equipped with a stirrer, reflux cooler, thermometer, and dropping funnel was charged with 500 g of a mixed solvent of methyl cellosolve and toluene (mass ratio 3:2), and after stirring and heating to 80°C, a solution prepared by mixing 100 g of methacrylic acid, 200 g of ethyl methacrylate, 100 g of ethyl acrylate, 100 g of styrene, and 0.8 g of azobisisobutyronitrile was slowly added dropwise over 4 hours. After the addition was completed, the reaction was continued for 2 hours. Next, 100 g of the mixed solvent (same composition as above) in which 1.2 g of azobisisobutyronitrile was dissolved was added dropwise over 10 minutes, and after the addition was completed, the reaction was further continued at 80°C for 3 hours and then at 90°C for 2 hours. After the reaction was completed, the alkali-soluble polymer B was obtained by filtration, and had an acid value of 196 mgKOH / g and a weight average molecular weight of about 80,000.

[0137] 3. Performance evaluation

[0138] 3.1 Evaluation method

[0139] Preparation of dry film

[0140] The photosensitive resin composition was sufficiently stirred, and applied uniformly on the surface of a 25 μm-thick polyethylene terephthalate film as a support using a bar coater, dried in a drying machine at 95°C for 5 minutes to form a photosensitive resin layer having a thickness of 40 μm, and then a 15 μm-thick polyethylene film as a protective layer was attached to the surface of the photosensitive resin layer on which the polyethylene terephthalate film was not laminated to obtain a dry film.

[0141] Flattening of substrate surface

[0142] As the substrate, a 1.2 mm-thick copper-clad laminate on which a 35 μm-thick rolled copper foil was laminated was used, and the surface was subjected to wet-type buffing roll grinding [Scotch-Brite (registered trademark) HD #600 manufactured by 3M Co., twice].

[0143] Lamination

[0144] The polyethylene film protective layer was peeled from the dry film, and then using a hot roll laminator (AL-70 manufactured by Asahi Kasei), it was laminated on a copper-clad laminate preheated to 60°C at a roll temperature of 105°C. The gas pressure was 0.35 MPa, and the lamination speed was 1.5 m / min.

[0145] Exposure

[0146] A mask was placed on a polyethylene terephthalate film as a support, and exposure was performed at 60 mJ / cm2using an ultrahigh pressure mercury lamp (HMW-201KB manufactured by ORC MANUFACTURING CO., LTD.).2 The photosensitive layer is exposed to the irradiation energy.

[0147] <Development>

[0148] The polyethylene terephthalate film was peeled off, and a 1 mass% aqueous Na2CO3 solution at 30°C was sprayed on the photosensitive resin layer using an alkali developing machine (a dry film developing machine manufactured by Fuji Kiko Co., Ltd.), and the unexposed portion of the photosensitive resin layer was dissolved and removed with a time twice the minimum developing time. The minimum developing time was the shortest time required for complete dissolution of the photosensitive resin layer in the unexposed portion.

[0149] 3.2 Evaluation Contents

[0150] (1) Dispersion stability

[0151] The photosensitive resin composition was sufficiently stirred, and the composition was uniformly coated on the surface of a 25-μm-thick polyethylene terephthalate film as a support using a bar coater. The photosensitive resin layer was formed by drying in a drying machine at 95°C for 5 min. Subsequently, the surface of the photosensitive resin layer was visually observed, and was classified in the following manner:

[0152] O: uniform surface;

[0153] *: surface precipitated undissolved matter.

[0154] (2) Photosensitivity

[0155] The photosensitive resin layer was exposed to light for 15 min using a 41-step phase exposure table manufactured by Stouffer having a brightness varying from transparent to black in 41 steps, to evaluate the photosensitivity thereof. After the exposure, development was performed with a time twice the minimum developing time, and was classified in the following manner based on the exposure amount at which the resist film was completely left in the phase exposure table in step 8:

[0156] O: exposure amount 20 mJ / cm 2 or less;

[0157] X: exposure amount 20 mJ / cm 2 - 50 mJ / cm 2 , not including the numerical limits;

[0158] *: exposure amount 50 mJ / cm 2 or more.

[0159] (3) Resolution

[0160] After exposure and development using a photomask having a wiring pattern of Line / Space = 10:10-150:150 (unit: μm), the resolution of the dry film was measured. The resolution is the minimum value of the pattern after the unexposed portion is completely removed from the resist pattern formed after exposure and development.

[0161] O: resolution value is below 30 μm;

[0162] ◎: resolution value is between 30 μm and 50 μm, inclusive;

[0163] *: resolution value is above 50 μm.

[0164] (4) Resist pattern shape

[0165] The resist pattern shape was observed using a scanning electron microscope (SEM) (Hitachi High-Technologies Corporation, product name "SU-1500") at an accelerating voltage of 15 kV, a magnification of 3000 times, and an inclination angle of 60 degrees, and was judged according to the following criteria:

[0166] O: the resist pattern shape was not confirmed to be undercut, the resist pattern upper portion was not missing, and the linearity of the pattern profile was good;

[0167] *: the resist pattern shape was confirmed to be undercut, the resist pattern upper portion was missing, and the linearity of the pattern profile was poor.

[0168] Table 5

[0169] The photoinitiator of the present application is applied to the photosensitive resin composition, which can make the photosensitive composition produce a complete resist pattern, the resist pattern shape is not confirmed to be undercut, the resist pattern upper portion is not missing, and the linearity of the pattern profile is good, and the photosensitive resin composition of the present application has good dispersion stability, higher resolution, and also has good sensitivity, and can meet the requirements of the EU halogen directive. The photosensitive resin composition can be widely used in the manufacture of printed circuit boards, protective patterns, conductor patterns, lead frame wires, semiconductor packaging, etc. in the form of dry film and wet film, and can also be applied to the manufacture of color filters and liquid crystal display assemblies.

[0170] The applicant declares that the photoinitiator, photosensitive resin composition and application thereof of the present application are illustrated by the above examples, but the present application is not limited to the above examples, i.e. it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A 2,2'-bis(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl- diimidazole photoinitiator having the structure of formula (I), ###00001### (I) wherein R is a C1-C4 alkyl group, and X is a halogen atom. wherein R represents a C3 to C8 straight chain or branched alkyl group.

2. The 2,2'-bis(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl-2H-diimidazole photoinitiator according to claim 1, wherein R is selected from the group consisting of n-propyl, iso-propyl, n-butyl, iso-butyl, n-pentyl, n-hexyl, n-heptyl, or n-octyl.

3. The 2,2'-bis(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl diimidazole photoinitiator according to claim 1 or 2, wherein The photoinitiator is selected from any one of the following compounds:

4. A photosensitive resin composition comprising the following components: (A) the 2,2'-bis(2-alkoxylphenyl)-4,4',5,5'-tetraphenyl-2,2'-biimidazole photoinitiator according to any one of claims 1 to 3; (B) an alkali-soluble polymer; (C) a compound having an ethylenically unsaturated double bond.

5. The photosensitive resin composition according to claim 4, wherein The content of the 2,2'-bis(2-alkoxylphenyl)-4,4',5,5'-tetraphenyl-2,2'-biimidazole photoinitiator is 1 to 10 parts by mass based on 100 parts by mass of the total weight of the photosensitive resin composition; Optionally, the alkali-soluble polymer is selected from one or more than two of a (meth)acrylic polymer, a styrene polymer, an epoxy polymer, an aliphatic polyurethane (meth)acrylate polymer, an aromatic polyurethane (meth)acrylate polymer, an amide resin, an amide epoxy resin, an alkyd resin, and a phenolic resin.

6. The photosensitive resin composition according to claim 4 or 5, wherein The weight average molecular weight of the alkali-soluble polymer is 15,000 to 200,000; Optionally, the acid value of the alkali-soluble polymer is 50 to 300 mgKOH / g; Optionally, the content of the alkali-soluble polymer is 20 to 70 parts by mass, further optionally 45 to 65 parts by mass, based on 100 parts by mass of the total weight of the photosensitive resin composition.

7. The photosensitive resin composition according to any one of claims 4 to 6, wherein The compound having an ethylenically unsaturated double bond is selected from one or more than two of a compound obtained by reacting an α,β-unsaturated carboxylic acid with a polyhydric alcohol, a bisphenol A (meth)acrylate compound, a compound obtained by reacting an α,β-unsaturated carboxylic acid with a glycidyl group-containing compound, a (meth)acrylate compound having an urethane bond in the molecule, a nonylphenoxy polyethyleneoxy acrylate, a γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate, a β-hydroxyethyl-β'-(meth)acryloyloxyethyl phthalate, a β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate, a phthalic acid compound, an alkyl (meth)acrylate, further optionally one or more than two of a combination of a bisphenol A (meth)acrylate compound and a (meth)acrylate compound having an urethane bond in the molecule; Optionally, the content of the compound having an ethylenically unsaturated double bond is 20 to 50 parts by mass, further optionally 30 to 50 parts by mass, based on 100 parts by mass of the total amount of the photosensitive resin composition.

8. The photosensitive resin composition according to any one of claims 4 to 7, wherein The photosensitive resin composition further comprises (D) other auxiliary agents; Optionally, the other auxiliary agents are selected from at least one of other photoinitiators and / or sensitizers, hydrogen donors, organic solvents, dyes, pigments, photochromic agents, fillers, plasticizers, stabilizers, coating aids, or peeling promoters; Optionally, the content of the other auxiliary agents is 0 to 10 parts by mass, further optionally 0.5 to 5 parts by mass, based on 100 parts by mass of the total amount of the photosensitive resin composition.

9. A photosensitive resin laminate comprising a photosensitive resin layer formed of the photosensitive resin composition according to any one of claims 4 to 8 and a support supporting the photosensitive resin layer.

10. Use of the 2,2'-bis(2-alkoxyphenyl)-4,4',5,5'-tetraphenyl-2H-tetrazolyl) photo-initiator according to any one of claims 1 to 3 or the photosensitive resin composition according to any one of claims 4 to 8 or the photosensitive resin laminate according to claim 9 in the manufacture of printed circuit boards, protective patterns, conductor patterns, lead frame lines, semiconductor packages.

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