JPH0721627B2 - Photopolymerizable composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photopolymerizable composition, and more particularly to a photopolymerizable composition having improved storage stability.

(Prior Art) Current printed wiring boards are provided with a layer of a photopolymerizable composition on the surface of a copper clad laminate, and the unexposed portion is washed away by imagewise exposure and development to obtain a photocured image and then exposed. Copper is removed by etching, then the photo-cured image is peeled off, the exposed copper portion is plated with a dissimilar metal, the photo-cured image is peeled off, and the exposed copper portion is etched. There is. Photopolymerizable compositions are widely used as such etching or plating photoresists. The photopolymerizable composition forms a uniform varnish once dissolved in a solvent, and is used by coating and drying it on a copper-clad laminate as it is, or after coating and drying on a film such as a polyester film. It is used by thermocompression bonding on a copper clad laminate.

Conventionally, a photopolymerizable composition comprising a compound having an ethylenically unsaturated group is used to form a complex with an amino compound and an amino compound by an actinic ray in order to increase the curing rate by actinic ray irradiation and to provide high photosensitivity. It is known to add photoinitiator systems consisting of compounds that generate radicals. For example, with aromatic ketones such as aminophenyl ketone
Using a combination with a 2,4,5-triarylimidazole dimer (JP-B-48-38403, U.S. Pat. No. 731733).
No.), using a combination of an aminophenyl ketone and an active methylene compound (JP-B-49-11936, US Patent).
877853) is known.

It is also known to add a color former system comprising a leuco dye and a halogen compound to the photopolymerizable composition in order to clearly distinguish the actinic ray-irradiated portion. For example, US Pat. No. 3,113,024 to Sprag et al. Describes the addition of a color former system consisting of a leucotriphenylmethane dye and a halogenated sulfone.

However, when the photoinitiator system and the color former system are blended at the same time as the photopolymerizable composition, there is a problem that the storage stability is lowered, and particularly when the composition is stored as a varnish, it is significantly unsatisfactory. It has the disadvantage of being stable and causing discoloration and gelation.

(Problems to be Solved by the Invention) An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and provide a photopolymerizable composition having excellent storage stability.

(Means for Solving Problems) As a result of various studies for achieving the above-mentioned object, the present inventors have made it possible to further add oxalic acid and / or oxalate to a conventionally known photopolymerizable composition. The present invention has been found out that the storage stability is remarkably improved even when the photoinitiator system and the color former system are blended at the same time.

The present invention comprises: (A) 30 to 100 parts by weight of a compound having at least one ethylenically unsaturated group and (B) 0 to 70 parts by weight of a thermoplastic organic polymer, and (A) and (B) in the total amount.
Included as 100 parts by weight, (C) with respect to 100 parts by weight of (A) and (B) 0.1 to 10 parts by weight of a group-containing compound (R ₁ and R ₂ each independently represent a hydrogen atom or a lower alkyl group),
(D) 1 to 20 parts by weight of a compound that forms a complex with component C by actinic rays to generate a radical, and (E) a leuco dye
0.1 to 5 parts by weight, 0.1 to 5 parts by weight of the (F) halogen compound, and (G) of oxalic acid and / or oxalate.
The present invention relates to a photopolymerizable composition containing 01 to 20 parts by weight and having the boiling point of each of the components (A) to (F) at 100 ° C. or higher at normal pressure.

Examples of the compound (component A) having at least one ethylenically unsaturated group used in the photopolymerizable composition of the present invention include compounds obtained by adding α, β-unsaturated carboxylic acid to polyhydric alcohol. , For example, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra Attaching α, β-unsaturated carboxylic acid to glycidyl group-containing compounds such as (meth) acrylate, polypropylene glycol di (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate Compound obtained by,
For example, trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate and the like, polyvalent carboxylic acids such as phthalic anhydride and a substance having a hydroxyl group and an ethylenically unsaturated group such as β-hydroxyethyl (meth) acrylate. And the like, alkyl esters of acrylic acid or methacrylic acid, such as (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth)
Acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester and the like can be mentioned. Two or more of these may be used if necessary.

The blending amount of the component (A) is 30 to 100 parts by weight, preferably 40 to 70 parts by weight, when the total amount of the component (B) and the component (A) described below is 100 parts by weight. This compounded amount is 30
When the amount is less than the amount by weight, the photocured product is brittle and sufficient physical properties cannot be obtained.

Examples of the thermoplastic organic polymer (component (B)) include copolymers of (meth) acrylic acid alkyl ester and (meth) acrylic acid, (meth) acrylic acid alkyl ester, (meth) acrylic acid, and these. A copolymer with a copolymerizable vinyl monomer is used. Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester (meth) acrylic acid butyl ester, and (meth) acrylic acid 2-ethylhexyl ester. Further, vinyl monomers that can be copolymerized with (meth) acrylic acid alkyl ester and (meth) acrylic acid include (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylethyl ester, and (meth) acrylic acid diethyl ester. , Methacrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate acrylamide, diacetone acrylamide, styrene, vinyltoluene and the like. The thermoplastic organic polymer (component (B)) includes terephthalic acid as an acid component, in addition to the homopolymer and copolymer of the above compound.
A copolyester obtained by using isophthalic acid or sebacic acid, a copolymer of butadiene and acrylonitrile, cellulose acetate, cellulose acetate butyrate, methyl cellulose, ethyl cellulose and the like can also be used. By using these thermoplastic organic polymers, the coating property and the film strength of the obtained cured product are improved.

The blending amount of the component (B) is 0 to 70 polymer, preferably 30 when the total amount of the component (A) and the component (B) is 100 polymer.
~ 60 parts by weight. If the blending amount is more than 70 parts by weight, the photosensitivity is lowered.

The weight average molecular weight of this thermoplastic organic polymer is preferably 10,000 or more from the viewpoint of coating property and film strength.

The components (A) and (B) are blended in such amounts that the total amount of both components is 100 parts by weight.

Used in the photopolymerizable composition of the present invention Examples of the group-containing compound (component (C)) include those represented by the general formula (In the formula, R ₁ and R ₂ are each independently a hydrogen atom or a lower alkyl group, and R ₃ is a group —OR ₄ or a group R ₄ represents a hydrogen atom or a lower alkyl group) and p-aminophenyl ketone. Examples of these specific compounds include 4,4′-bis (dimethylamino) benzophenone [Michler-ketone], 4,
4'-bis (diethylamino) benzophenone, dimethylaminobenzoic acid ethyl ester, dimethylaminobenzoic acid butyl ester, dimethylaminobenzoic acid isoamyl ester and the like.

Examples of the component (C) include amines such as di (n-propyl) amine, tri (n-butyl) amine, triamylamine, propylenediamine and aniline, in addition to the compound represented by the general formula (I). Used.

The compounding amount of the component (C) is 0.1 to 10 parts by weight, preferably 1.0 part by weight based on 100 parts by weight of the total amount of the components (A) and (B).
~ 7 parts by weight. If this blending amount is less than 0.1 parts by weight, a practical photo-curing rate cannot be obtained, and if it is more than 10 parts by weight, the stability may decrease or the curing of the resist bottom may not proceed. is there.

Examples of the compound (component (D)) which is used in the photopolymerizable composition of the present invention to form a radical by forming a complex with the component (C) by actinic rays include benzophenone and 2-
Chlorthioxanthone, 2,4-diethylthioxanthone, 2-propylthioxanthone and the like can be mentioned.

The compounding amount of the component (D) is 1 to 20 parts by weight, preferably 2-1 to 100 parts by weight of the total amount of the components (A) and (B).
0 parts by weight. If this amount is less than 1 part by weight, a practical photohardness rate cannot be obtained, and if it is more than 20 parts by weight, the stability may decrease or the curing of the resist bottom may not proceed. is there.

Preferred combinations of the component (C) and the component (D) include, for example, 4,4'-bis (dimethylamino) benzophenone / benzophenone, 4,4'-bis (diethylamino) benzophenone / benzophenone, ethyl dimethylaminobenzoate. Ester / 2,4-diethylthioxanthone, dimethylaminobenzoic acid isoamyl ester / 2,4-
Examples thereof include diethylthioxanthone and dimethylaminobenzoic acid isoamyl ester / 2-propylthioxanthone.

Examples of the leuco dye (component (E)) used in the photopolymerizable composition of the present invention include tris (4-dimethylamino-2-methylphenyl) methane [leuco crystal violet] and tris (4-diethylamino-2-). Methylphenyl) methane leuco malachite green and the like.

The blending amount of the component (E) is 0.1 to 5 parts by weight, preferably 0.5 to 100 parts by weight of the total amount of the components (A) and (B).
~ 3 parts by weight. When the content is less than 0.1 parts by weight, sufficient color development is not performed by irradiation with actinic rays, and when it is more than 5 parts by weight, the stability decreases.

The halogen compound (component (F)) used in the photopolymerizable composition of the present invention liberates a halide free radical upon irradiation with an actinic ray to develop a color of the leuco dye of component (E). Amyl, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenyl sulfone, carbon bromide, tris (2,3-dibromopropyl) phosphate, trichloro Acetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-
Examples thereof include bis (p-chlorophenyl) ethane, hexachloroethane, methyl methacrylate-tribromophenyl acrylate copolymer, methyl methacrylate-dibromopropyl acrylate copolymer and the like.

The content of the component (F) is 0.1 to 5 parts by weight, preferably 0.5 to 5 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B).
3 parts by weight. When the content is less than 0.1 part by weight, sufficient color development is not achieved by irradiation with actinic rays, and when it is more than 5 parts by weight, the stability is lowered.

As a preferable combination of the component (E) and the component (F), for example, leuco crystal violet / 4 carbon bromide,
Leuco crystal violet / tribromomethyl phenyl sulfone, leuco crystal violet / 1,1,1
-Trichloro-2,2-bis (p-chlorophenyl) ethane, tris (4-diethylamino-2-methylphenyl) methane / 4 carbon bromide, tris (4-diethylamino-)
2-Methylphenyl) methane / tribromomethylphenyl sulfone, tris (4-diethylamino-2-methylphenyl) methane / 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane and the like can be mentioned.

In the photopolymerizable composition of the present invention, oxalic acid and / or oxalate (component (G)) is used to improve storage stability. Examples of the oxalate include malachite green oxalate, sodium oxalate,
Potassium oxalate, ammonium oxalate and the like are used.

The blending amount of the component (G) is 0.01 to 20 parts by weight, preferably 0.1 to 100 parts by weight of the total amount of the components (A) and (B).
~ 5 parts by weight. If this blending amount is less than 0.01 parts by weight, the stability during storage cannot be sufficiently maintained,
On the other hand, when it is more than 20, it is not sufficiently dispersed in the photopolymerizable composition.

The photopolymerizable composition of the present invention may contain a thermal polymerization inhibitor such as p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, phenothiazine and t-butylcatechol.

Further, the photopolymerizable composition of the present invention may contain a colorant such as a dye or a pigment. As the colorant, for example, fuchsin, auramine base, crystal violet, Victoria pier blue, malachite green, methyl orange, and assid violet RRH are used.

Further, known additives such as a plasticizer, an adhesion promoter and talc may be added to the photopolymerizable composition of the present invention.

Each of the components (A) to (F) of the photopolymerizable composition is required to have a boiling point of 100 ° C. or higher under normal pressure. When the boiling point of each of these components is lower than 100 ° C., the varnish of the photopolymerizable composition is volatilized during drying after being applied on the support.

The photopolymerizable composition of the present invention is a solvent that dissolves the above components A to G, such as toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, chloroform, methylene chloride, methyl. A uniform varnish can be obtained by dissolving and mixing in alcohol, ethyl alcohol or the like.

The photopolymerizable composition of the present invention can be used by directly coating it on a substrate such as a copper plate, drying it, exposing it to actinic rays, and photocuring it. Alternatively, the varnish may be applied on a film such as a polyester terephthalate film, dried, and then laminated on a substrate and photocured for use.

As a light source of actinic rays used for photocuring, a wavelength of 30
Those that emit light of 0 to 450 nm are used, and for example, mercury vapor arc, carbon arc, and xenon arc are preferable.

(Effects of the Invention) Although the photopolymerizable composition of the present invention simultaneously contains a photoinitiator system for producing high photosensitivity and a color former system for clarifying the actinic ray irradiation portion, It has excellent storage stability.

The photopolymerizable composition of the present invention can be used, for example, as a photoresist for etching or plating, using a photocurable film as a relief or using a copper clad laminate as a substrate.

(Example) Hereinafter, the present invention will be described with reference to an example.

Examples 1 to 6 Methylmethacrylate / methacrylic acid / 2-ethylhexyl acrylate (weight ratio 60/20/20) copolymer (weight average molecular weight = 80,000) in 40.0% by weight methylcellosolve solution 13
0 g (polymer component 52 g), tetraethylene glycol diacrylate 10 g, poly (p≈5) oxyethylenated bisphenol A dimethacrylate (BPE-10 manufactured by Shin-Nakamura Chemical Co., Ltd.) 30 g, leuco crystal violet
1.0g, carbon bromide 1.0g, hydroquinone 0.1g and ME
K (10 g) and toluene (10 g) were mixed to obtain 192.1 g of solution (I) (total nonvolatile content 94.1 g, nonvolatile content concentration 49.0% by weight).

Next, the components shown in Table 1 were added to this solution (I) to obtain a photopolymerizable composition of the present invention (the unit of Table 1 is g
Is).

This composition was stored in the dark at 23 ° C., and the stability of the varnish was evaluated by examining the number of days until discoloration and gelation. The results are shown in Table 1.

In the table, the symbol ◯ means no abnormality, the symbol Δ means discoloration or thickening, and the symbol x means gelation.

Comparative Examples 1 to 4 The components shown in Table 1 were added to the solution (I) and treated in the same manner as in Example 1 to obtain a photopolymerizable composition. For this composition, a varnish was prepared in the same manner as in Example 1. Table 1 shows the results of evaluating the stability of the.

From the results in Table 1, it is shown that the photopolymerizable composition of the present invention is excellent in storage stability, but the photopolymerizable compositions of Comparative Examples are remarkably low in storage stability.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshitaka Minami 4-13-1, Higashimachi, Hitachi-shi, Ibaraki Hitachi Chemical Co., Ltd. Yamazaki factory (56) References JP-A-57-21890 (JP, A) ) JP-A-50-70101 (JP, A)

Claims (1)

[Claims] 1. A total amount of (A) and (B) of (A) 30 to 100 parts by weight of a compound having at least one ethylenically unsaturated group and (B) 0 to 70 parts by weight of a thermoplastic organic polymer. As 100 parts by weight, and (C) with respect to 100 parts by weight of (A) and (B) 0.1 to 10 parts by weight of a group-containing compound (R ₁ and R ₂ each independently represent a hydrogen atom or a lower alkyl group),
(D) 1 to 20 parts by weight of a compound that forms a complex with component C by actinic rays to generate a radical, and (E) a leuco dye
0.1 to 5 parts by weight, 0.1 to 5 parts by weight of the (F) halogen compound, and (G) of oxalic acid and / or oxalate.
A photopolymerizable composition comprising 01 to 20 parts by weight and having the boiling point of each of the components (A) to (F) at 100 ° C. or higher at normal pressure.