JP2856746B2 - Photopolymerizable composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photopolymerizable composition, and more particularly, to a photopolymerizable composition having an improved photo-setting speed.

[Prior Art and Problems to be Solved by the Invention] Photopolymerizable compositions are widely used in the production of printed circuit boards, integrated circuits, metal relay images and printing plates. The photopolymerizable composition usually contains a thermoplastic polymer binder, a photopolymerization initiator, a polymerization accelerator, an addition polymerizable compound, and the like, and is usually used in the form of a solution or a dry film. You. Then, a solution-type photopolymerizable composition or a dry film-form photopolymerizable composition dissolved in an organic solvent is applied or laminated on the surface of a copper-clad laminate for a printed board or a metal substrate to be subjected to fine processing. The resist image is formed by laminating, exposing a predetermined pattern with actinic rays, and developing an unexposed portion with a developing solution.

In addition, since the active region of the photopolymerization initiator is usually in the ultraviolet region, the exposure is performed with active light containing the ultraviolet region. Therefore, in order to increase the productivity of a printed wiring board or the like, it is required that the sensitivity to actinic rays is high and the photo-setting speed is high.

However, the conventional photopolymerizable composition has a problem that the photosensitive curing speed is not yet sufficient, and the exposure time becomes longer and the productivity is reduced.

An object of the present invention is to provide a photopolymerizable composition having a high photosensitive curing speed.

[Constitution of the Invention] The present inventors have conducted intensive studies and as a result of combining a specific alkylaminobenzoic acid alkyl ester with a photopolymerization initiator, a specific thermoplastic polymer binder and an addition polymerizable compound, It has been found that a photopolymerizable composition having an excellent photosensitive curing speed can be obtained. That is, the present invention provides: (1) at least a (meth) acrylic monomer, a carboxyl group-containing monomer, and a styrene monomer, and the (meth) acrylic monomer is an acrylate ester and / or methacrylic acid. A thermoplastic resin composed of an ester, wherein the ratio of the styrene-based monomer and the (meth) acrylic monomer is 10/90 to 60/40 (weight ratio); 100 parts by weight of a polymer binder, (2) 0.01 to 30 parts by weight of thioxanthone optionally having a halogen atom or an alkyl group, and (3) the following general formula (I) (Wherein, R ₁ represents a C _3-4 branched alkyl group, R ₂ represents a methyl or ethyl group, and R ₃ represents an alkyl group having 1 to 20 carbon atoms).
01 to 30 parts by weight, and (4) a liquid or solid addition polymerizable compound 10 at normal temperature and normal pressure
The above-mentioned object is achieved by a photopolymerizable composition containing up to 20 parts by weight.

First, the thermoplastic polymer binder will be described. As the thermoplastic polymer binder, a copolymer of a styrene monomer, a (meth) acrylic monomer composed of an acrylate and / or a methacrylate, and a carboxyl group-containing monomer is used. .

Examples of the styrene monomer include styrene, α-substituted styrene in which the α-position is substituted with an alkyl group or a halogen atom, for example, α-methylstyrene, α-chlorostyrene, and the like; substituted styrene in which a hydrogen atom of a benzene ring is substituted For example, p-methylstyrene, p-ethylstyrene, p-propylstyrene, p-isopropylstyrene, p- (tert-butyl) styrene and the like are exemplified, and at least one kind is used. Among the styrene monomers, styrene, α-methylstyrene and the like are preferred.

As the acrylate, for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate Octyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, and the like. Examples of the methacrylate include methacrylate corresponding to the above acrylate. One or more of these acrylates and methacrylates are used.

When the unexposed portion is removed and developed with an alkali developer or the cured film is peeled off, it is effective to copolymerize an addition polymerizable monomer having a carboxyl group.
Examples of such an addition-polymerizable monomer include maleic acid, itaconic acid, methacrylic acid, and acrylic acid.

The thermoplastic polymer is composed of an appropriate ratio of each monomer. When the thermoplastic polymer is composed of a styrene monomer, an acrylate ester and / or a methacrylate ester, the styrene monomer is usually 10 to 60% by weight, Acid esters and methacrylic esters are about 90 to 40% by weight. When an acrylic ester and a methacrylic ester are used in combination, the acrylic ester / methacrylic ester is usually 20 to 65/80 to 35, preferably 3 in weight ratio.
It is used at a ratio of about 0-50 / 70-50. The addition-polymerizable monomer having a carboxyl group is usually used in an amount of about 15 to 40% by weight based on a total amount of 60 to 85% by weight of the styrene monomer, the acrylate and the methacrylate.

Examples of the thioxanthone which may have a halogen atom or an alkyl group include, for example, thioxanthone, its halogenated 2-chlorothioxanthone, its alkylated 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone 2,4
-Dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dibutylthioxanthone and the like.

The thioxanthone optionally having a halogen atom or an alkyl group is used alone or in combination of two or more.
Thioxanthone or the like is used in an amount of 0.01 to 30 parts by weight, preferably 1 to 15 parts by weight, based on 100 parts by weight of the thermoplastic polymer binder. If the amount of thioxanthone or the like relative to the thermoplastic polymer binder is less than 0.01 part by weight, the photosensitive curing speed is not sufficient, and if it exceeds 30 parts by weight, the properties of the cured film are deteriorated.

In the compound represented by the general formula (I), R ₁ , R ₂ and R ₃
Examples of the alkyl group include a methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 12-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, octadecyl, icosyl group And linear or branched alkyl groups. However, R ₁ is a branched alkyl group having 3 to 4 carbon atoms (C _3-4 branched alkyl group), particularly an isopropyl group, R ² is a methyl group or an ethyl group, and R ₃ is a C ₁ to C ₁ alkyl group. 20 alkyl groups.

Among the compounds represented by the general formula (I), preferred alkylaminobenzoic acid alkyl esters include p- (N
-Methyl-N-isopropylamino) methyl benzoate,
Methyl p- (N-ethyl-N-isopropylamino) benzoate, p- (N-methyl-N-isopropylamino)
Ethyl benzoate, ethyl p- (N-ethyl-N-isopropylamino) benzoate, propyl p- (N-ethyl-N-isopropylamino) benzoate, p- (N-ethyl-N-isopropylamino) benzoic acid Amyl, p- (N
-Ethyl-N-isopropylamino) imiamyl benzoate and the like.

Compounds represented by the general formula (I) are other alkylaminobenzoic acid alkyl esters such as propyl p- (N-propyl-N-isopropylamino) benzoate,
-(N, N-diisopropylamino) methyl benzoate, p
-(N-butyl-N-isopropylamino) methyl benzoate, p- (N-propyl-N-isopropylamino)
Ethyl benzoate, p- (N, N-diisopropylamino)
Ethyl benzoate, methyl p- (N-butyl-N-isopropylamino) benzoate, butyl p- (N-butyl-N-isopropylamino) benzoate, p- (N-butyl-
Methyl N-isopropylamino) benzoate, p- (N, N
-Diisopropylamino) amyl benzoate, p- (N, N
-Diisopropylamino) isoamyl benzoate, p-
Isoamyl (N-butyl-N-isopropylamino) benzoate, methyl p- (N-hexyl-N-isopropylamino) benzoate, ethyl p- (N-hexyl-N-isopropylamino) benzoate, p- (N -Hexyl-
Hexyl N-isopropylamino) benzoate, p- (N
Propyl-hexyl-N-isopropylamino) benzoate, isoamyl p- (N-hexyl-N-isopropylamino) benzoate, methyl p- (N-heptyl-N-isopropylamino) benzoate, p- (N-heptyl) -N
-Isopropylamino) ethyl benzoate, p- (N-heptyl-N-isopropylamino) heptyl benzoate,
It may be used in combination with propyl p- (N-heptyl-N-isopropylamino) benzoate, isoamyl p- (N-heptyl-N-isopropylamino) benzoate and the like.

At least one kind of the alkylaminobenzoic acid alkyl ester represented by the general formula (I) is used. The alkylaminobenzoic acid alkyl ester is used in an amount of 0.01 to 30 parts by weight, preferably 1 to 15 parts by weight, based on 100 parts by weight of the thermoplastic polymer binder. If the amount of the alkylaminobenzoic acid alkyl ester is less than 0.01 part by weight, it is difficult to increase the photo-curing speed, and if it exceeds 30 parts by weight, the properties of the cured film deteriorate. The alkylaminobenzoic acid alkyl ester represented by the general formula (I) has excellent compatibility with a thermoplastic polymer binder and the like, contributes to stabilization of the photopolymerizable composition, and has a low photo-setting speed. Significantly promote.

In the present invention, in order to further enhance the photocurability,
The combination use of the thioxanthone or the like, an alkylaminobenzoic acid alkyl ester represented by the general formula (I), and a 2,4,5-triarylimidazolyl dimer represented by the following general formula (II) preferable.

(Wherein, Ar ₁ , Ar ₂ and Ar ₃ represent an optionally substituted aryl group) Examples of the 2,4,5-triarylimidazolyl dimer represented by the general formula (II) include: 2,2 ', 4,4', 5,5'-
Hexaphenylbisimidazole, 2,2'-di (o-chlorophenyl) -4,4 ', 5,5'-tetraphenylbisimidazole, 2,2'-di (o-chlorophenyl) -4,
4 ', 5,5'-tetra (m-methoxyphenyl) bisimidazole, 2,2'-di (o-fluorophenyl) -4,
4 ', 5,5'-tetraphenylbisimidazole, 2,2'-
Di (o-methoxyphenyl) -4,4 ', 5,5'-tetraphenylbisimidazole, 2,2'-di (p-chlorophenyl) -4,4', 5,5'-tetraphenylbisimidazole, 2,2'-di (p-chlorophenyl) -4,4 ', 5,5'-
Tetra (m-methoxyphenyl) bisimidazole, 2,
2'-di (p-fluorophenyl) -4,4 ', 5,5'-tetraphenylbisimidazole, 2,2'-di- (p-methoxyphenyl) -4,4', 5,5'- Examples include tetraphenylbisimidazole and the like. At least one 2,4,5-triarylimidazolyl dimer represented by the general formula (II) is used. 2,4,5-Triarylimidazolyl dimer represented by the general formula (II) is a thermoplastic polymer binder
0.01 to 30 parts by weight, preferably 1 to 15 parts by weight per 100 parts by weight
Used by weight. If the amount of the 2,4,5-triarylimidazolyl dimer is less than 0.01 part by weight, it is difficult to increase the photosensitive curing speed, and if it exceeds 30 parts by weight, the properties of the cured film are deteriorated.

Examples of the addition polymerizable compound include acrylates and methacrylates which are liquid or solid at normal temperature and normal pressure and have two or more acryloyl groups or methacryloyl groups in the molecule.

Examples of the acrylate having two acryloyl groups in the molecule include ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, and dipropylene glycol. Diacrylate, tripropylene glycol diacrylate, tetrapropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, ethylene oxide addition of bisphenol A Diacrylate, bisphenol A propylene oxide adduct dia Acrylate, diacrylate of ethylene oxide adduct of hydrogenated bisphenol A, diacrylate of propylene oxide adduct of hydrogenated bisphenol A, N, N'-methylenebisacrylamide, N, N'-benzylidenebisacrylamide and the like. .

Examples of the acrylate having three or more acryloyl groups in the molecule include glycerin triacrylate,
Examples thereof include trimethylolpropane triacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

Examples of the methacrylate having two or more methacryloyl groups in the molecule include methacrylates corresponding to the above acrylates.

At least one of the above acrylates and methacrylates is used, and both may be used as a mixture. In addition,
Monofunctional acrylates and methacrylates may be appropriately used in combination.

The amount of the addition polymerizable compound is usually 10 to 200 parts by weight, preferably 20 to 15 parts by weight per 100 parts by weight of the thermoplastic polymer binder.
It is about 0 parts by weight.

The photopolymerizable composition of the present invention may contain a stabilizer, a coloring agent, a coloring agent for facilitating discrimination of a resist image, a plasticizer for imparting flexibility, if necessary, for suppressing a thermal polymerization reaction and for enhancing storage stability. And the like. Examples of the stabilizer include p-methoxyphenol, hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol and the like, and are used in an appropriate amount as long as the photopolymerizability is not inhibited. As the coloring agent, a leuco compound of a triarylmethane dye is useful, for example, leuco crystal violet, leucomalachite green, or a mineral acid salt such as hydrochloride or sulfate of these leuco compounds, p-toluenesulfonic acid Organic acid salts such as salts are exemplified. Examples of the coloring agent include crystal violet, malachite green, Victoria blue, methylene blue and the like. As the plasticizer, for example, diethyl phthalate,
Phthalic acid esters such as dibutyl phthalate, diheptyl phthalate and dioctyl phthalate; fatty acid esters such as dioctyl adipate and dibutyl diglycol adipate; phosphoric acid esters such as trimethylphosphine; sulfonic acid amides such as toluene sulfonic acid amide; Is exemplified.

The photopolymerizable composition of the present invention may be a liquid containing no organic solvent, but is usually used in the form of a liquid or a dry film dissolved or dispersed in an organic solvent. Examples of the organic solvent include alcohols such as methanol, ethanol, and propanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran; and halogenated hydrocarbons such as methylene chloride. And the like. The dry film is produced, for example, by applying a polymerizable composition to a base film such as a polyethylene terephthalate film, drying, and then laminating a cover film such as a polyethylene film with a pressure roll or the like. The thickness of the photopolymerizable composition of the dry film is not particularly limited as long as the resolution and workability are not reduced, but is usually 5 to 100 μm, preferably 20 to 70 μm.

The photosensitive layer comprising the photopolymerizable composition of the present invention is usually prepared by printing or coating a liquid photopolymerizable composition containing an organic solvent on a support such as a printed circuit board to remove the organic solvent or dry the photopolymerizable composition. It is formed by peeling the cover film of the film and laminating the film on the support with a rubber roll or the like.

The photosensitive layer is a light source that generates chemically active radiation,
For example, exposure is performed with a light source such as a low-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a xenon lamp. In general, light is emitted by a contact method or a projection method using a negative or positive pattern mask provided with a cover sheet on the photosensitive layer as necessary. After exposure, development with a developer provides a resist image corresponding to the pattern. As the developing solution, a developing solution comprising an organic solvent such as perchloroethylene and trichloroethane, an alkaline developing solution containing a basic compound, and the like can be used. As the basic compound of the alkali developer,
Examples thereof include inorganic bases such as potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate sodium silicate, and sodium phosphate; and organic bases such as trimethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, morpholine, and pyridine. You. Note that the alkali developer may contain an organic solvent such as ethylene glycol monobutyl ether.

When a circuit pattern is formed, after forming a resist image, the resist image is treated with a plating solution or an etching solution, and the resist image is peeled off with a strong alkaline aqueous solution such as sodium hydroxide or an organic solvent such as methylene chloride. .

The photopolymerizable composition of the present invention can be used as a photoresist when producing a printed wiring board, a circuit board, a metal relief image, a printing plate, or the like.

[Effects of the Invention] According to the photopolymerizable composition of the present invention, the specific alkylaminobenzoic acid alkyl ester is combined with a photopolymerization initiator, a thermoplastic polymer binder, and an addition polymerizable compound, so that it is excellent. As a result, the exposure time can be shortened as compared with the conventional photopolymerizable composition, and the productivity of a printed wiring board or the like can be increased.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples.

Example 1 The following components were mixed to obtain a photopolymerizable composition.

14% by weight of methacrylic acid, 14% by weight of acrylic acid, styrene
20% by weight, 52% by weight of 2-ethylhexyl methacrylate
50 g 2,4-Diethylthioxanthone 1 g Amyl p-N-ethyl-N-isopropylaminobenzoate 3 g Trimethylolpropane triacrylate 15 g Tetraethylene glycol diacrylate 10 g Victoria blue GH 0.05 g Methyl ethyl ketone 60 g Tetrahydrofuran 10 g was obtained. The photopolymerizable composition was applied to a 25 μm-thick polyethylene terephthalate film support and dried at 75 ° C. to obtain a photosensitive film. The thickness of the photosensitive layer was 50 μm. The obtained photosensitive film was laminated on a polished copper-clad laminate with a rubber roller heated to 100 ° C.
Next, a 21-step Stofa step tablet is superimposed on the dry film and irradiated with a 2 kw ultra-high pressure mercury lamp from a distance of 50 cm for 10 seconds to cure the film. After spray development for 70 seconds, a resin relief image corresponding to "8" on the step tablet was obtained.

Reference Example 1 50 g of polymethyl methacrylate, 1 g of 2-chlorothioxanthone, 3 g of ethyl p-N-methyl-N-isopropylaminobenzoate, 15 g of trimethylolpropane triacrylate, 10 g of tetraethylene glycol diacrylate,
A photopolymerizable composition was obtained in the same manner as in Example 1 except that 0.05 g of Victoria Blue GH, 60 g of methyl ethyl ketone, and 10 g of amyl tetrahydrofuran were used. When this photopolymerizable composition was evaluated in the same manner as in Example 1, a resin relief image corresponding to “8” of the step tablet was obtained.

Reference Example 2 A photopolymerizable composition was prepared using a copolymer of 20% by weight of methacrylic acid, 60% by weight of methyl methacrylate, and 20% by weight of isobutyl acrylate in place of the copolymer of Example 1. When the photosensitive characteristics were evaluated in the same manner as in Example 1, a resin relief image corresponding to "8" of the step tablet was obtained.

Reference Example 3 To the photopolymerizable composition of Reference Example 2, 2 g of 2,2'-di (o-chlorophenyl) -4,4 ', 5,5'-tetra (m-methoxyphenyl) bisimidazole was added, The photopolymerizable composition was obtained by mixing.

The photosensitive characteristics were examined in the same manner as in Reference Example 2 except that the exposure time was changed to about 7.5 g. As a result, a resin relief image corresponding to "8" of the step tablet was obtained. The curing speed was high. Comparative Example 1 A photopolymerizable composition not containing amyl p- (N-ethyl-N-isopropylamino) benzoate among the components constituting the photopolymerizable compositions of Example 1 and Reference Example 2 was obtained. When each photopolymerizable composition was evaluated in the same manner as in Example 1, only a relief image corresponding to “4” of the step tablet was obtained.

Comparative Example 2 In the photopolymerizable composition of Example 1, p- (N-ethyl-N
-Isopropylamino) amyl benzoate, p-
A photopolymerizable composition was obtained using ethyl (N-butylamino) benzoate.

When this photopolymerizable composition was evaluated in the same manner as in Example 1, only a resin relief image corresponding to “7” of the step tablet was obtained.

Comparative Example 3 In the photopolymerizable composition of Example 3, p- (N-ethyl-N
-Isopropylamino) amyl benzoate, p-
A photopolymerizable composition was obtained using ethyl (Nn-butylamino) benzoate.

When this photopolymerizable composition was evaluated in the same manner as in Example 1, only a resin relief image corresponding to “6” of the step tablet was obtained.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03F 7/004-7/031 C08F 2/50

Claims (2)

(57) [Claims] 1. A composition comprising at least a (meth) acrylic monomer, a carboxyl group-containing monomer and a styrene monomer, wherein the (meth) acrylic monomer comprises an acrylic ester and / or a methacrylic ester. The ratio of the styrene monomer and the (meth) acrylic monomer is the former / the latter = 10 / 90-60 / 40 (weight ratio)
100 parts by weight of a thermoplastic polymer binder composed of a copolymer of the following monomers, 0.01 to 30 parts by weight of thioxanthone which may have a halogen atom or an alkyl group, and the following general formula (I) (Wherein, R ₁ represents a C _3-4 branched alkyl group, R ₂ represents a methyl or ethyl group, and R ₃ represents an alkyl group having 1 to 20 carbon atoms).
01 to 30 parts by weight, liquid or solid addition polymerizable compound at normal temperature and pressure 10 to 200
A photopolymerizable composition, comprising: 2. A 2,4,5-triarylimidazolyl dimer of 0.01 to 30 parts by weight per 100 parts by weight of a thermoplastic polymer binder.
The photopolymerizable composition according to claim 1, which contains parts by weight.