JP2938213B2 - Photosensitive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-soluble photosensitive composition.

[0002]

2. Description of the Related Art A composition containing a polyvinyl alcohol polymer, a radically polymerizable unsaturated compound and a photopolymerization initiator is called a photosensitive composition, and is widely used, for example, as a relief material for printing. After the photosensitive composition is adjusted to a sheet shape (referred to as a photosensitive resin plate) on a support such as a metal plate or a film plate, it is exposed to light and developed into a resin relief, but a polyvinyl alcohol polymer is used. The photosensitive composition used has been awarded in the printing field because the uncured portion can be easily eluted with water after exposure, and the plate making operation is easy.

However, in a photosensitive composition using a conventional polyvinyl alcohol-based polymer, when the uncured portion is removed by washing with water after exposure, that is, at the time of development, even the cured portion of the polyvinyl alcohol-based polymer is removed. At present, the properties of the resulting relief printing plate are significantly impaired.

[Problems to be solved by the invention]

[0004] The present invention is intended to overcome the disadvantages of the above-described photosensitive composition using a conventional polyvinyl alcohol-based polymer, that is, the water-soluble property of the cured portion during the water development without dropping off of the polyvinyl alcohol-based polymer. It is intended to obtain a photosensitive composition having the same.

[0005]

Means for Solving the Problems The inventors of the present invention have developed a water-soluble polymer which does not lose the polyvinyl alcohol-based polymer in a cured portion during water development while maintaining the excellent properties inherent in the polyvinyl alcohol-based photosensitive composition. As a result of intensive studies on the light-sensitive composition, it was found that the above-mentioned object was achieved by using a polyvinyl alcohol-based polymer having a radically polymerizable ethylenic double bond in the molecule as the polyvinyl alcohol-based polymer. The present invention has been completed under the heading.

Namely, the present invention is, (a) polyvinyl alcohol polymer that have a radical polymerizable ethylenic double bond in the molecule, (b) an unsaturated compound having a radical polymerizable ethylenic double bond And (c) a photosensitive composition containing a photopolymerization initiator.

[0007] The polyvinyl alcohol-based polymer of (a)
Any substance having a radically polymerizable ethylenic double bond in the molecule can be used,
When a large amount of radically polymerizable ethylenic double bond is present in the molecule, the properties such as toughness and good water solubility of the film originally possessed by polyvinyl alcohol are lost.
What contains the structural unit represented by the following [Chemical formula 1] or [Chemical formula 2] in a polyvinyl alcohol polymer in an amount of 0.1 to 30 mol%, preferably 0.5 to 30 mol%, more preferably 1.0 to 30 mol%. preferable.

[0008]

Embedded image

(Where R ¹ is hydrogen or a methyl group, R ² is hydrogen or an alkyl group having 1 to 4 carbon atoms, R ³ is hydrogen or an alkyl group having 1 to 3 carbon atoms, (X) is an ester bond shown below) linking group represented by connected to carbon constituting double bond in the side (X _1), connected to carbon constituting double bond in R ⁷ side (X
₂ ) a linking group represented by (X ₃ ) or a linking group linked to a carbon constituting a double bond on the O side, ^{_{(X 2): - R 6}} -O-R 7 - (R 6 and R ⁷ are 1 to carbon atoms
10 alkylene _{group) (X 3): - R} 6 -O- (R 6 denotes a alkylene groups) of 1 to 10 carbon atoms. )

[0010]

Embedded image

(Where R ¹ is hydrogen or methyl, R ² is hydrogen or alkyl having 1 to 4 carbons, R ³ is hydrogen or alkyl having 1 to 3 carbons, R ⁴ is 1 to 3 carbons) alkylene group, linked to carbon constituting double bond in (X) of the linking group represented by connected to carbon constituting double bond in an ester bond side of the following (X _1), R ⁷ side ( (X ₃ ) linking to the linking group represented by X ₂ ) or the carbon constituting the double bond on the O side
A linking group represented by ^{_{(X 2): - R 6}} -O-R 7 - (R 6 and R ⁷ are 1 to carbon atoms
10 alkylene _{group) (X 3): - R} 6 -O- (R 6 denotes a alkylene groups) of 1 to 10 carbon atoms. )

The degree of polymerization of the polyvinyl alcohol-based polymer is
10 or more, preferably 10 to 30,000, more preferably 100 to 4000, and most preferably 300 to 3000. The degree of saponification of the polyvinyl alcohol polymer is not particularly limited as long as it is water-soluble or water-dispersible, but is preferably at least 65 mol%.

The polyvinyl alcohol-based polymer of the present invention may contain various monomer units as long as the effects of the present invention are not impaired. Examples of these monomer units include ethylene, propylene, 1-butene, isobutylene, vinyl formate, vinyl propionate, vinyl versatate, (meth) acrylic acid and salts thereof, itaconic acid, maleic acid, fumaric acid and And (meth) acrylamide, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid and salts thereof, (meth) acrylamidopropyltrimethylammonium chloride, N-vinylpyrrolidone, allyl alcohol, allyl acetate and the like. The degree of saponification is not particularly limited when these monomer units are contained, as long as the polymer is water-dispersible or water-soluble.

As the unsaturated compound having an ethylenic double bond (hereinafter abbreviated as polymerizable monomer) of (b), any of those which can be radically polymerized with a photoinitiator can be used. Those having good compatibility with the coalescence and the photopolymerization initiator are preferably used. Examples of such examples include the following. Ethylene glycol acrylate, ethylene glycol methacrylate,
Ethylene glycol dimethacrylate, triethylene glycol methacrylate, triethylene glycol dimethacrylate, polyethylene glycol methacrylate, polyethylene glycol dimethacrylate, β-oxypropyl methacrylate, β-oxyethyl methacrylate, and N-β-oxyethylacrylamide;
N-oxymethylacrylamide, N, N'-bis (β-
Oxyethyl) acrylamide, N-γ-oxypropyl acrylamide, Np-oxyphenyl acrylamide, N-β-oxyethyl N′-methyl acrylamide, and methacrylamide derivatives corresponding thereto, and the like, and further acrylamide, methacrylamide, m-xylylenebisacrylamide, p-xylylenebismethacrylamide, m-phenylenebisacrylamide, ethylenediaminebisacrylamide, hexamethylenediaminebismethacrylamide and the like. These monomers are used alone or as a mixture.

Examples of the photopolymerization initiator (c) include benzophenone, benzoin, p, p'-dimethylbenzoin, benzoylmethyl ether, benzoin isopropyl ether, acyloin or a nuclei-substituted aromatic acyloin or acyloin alkyl ether, diacetyl, Benzyl, ketoaldonyl compounds, 1,1'-azocyclohexanecarbonitrile, azonitrile, 9,10-anthraquinone, chloranthraquinone, 1,4-naphthoquinone, 9.1
0-phenantrequinone and the like.

In the photosensitive composition of the present invention, (a) is preferably used in an amount of 30 to 250 parts by weight, (b) in an amount of 30 to 250 parts by weight, and (c) in an amount of 0.01 to 15 parts by weight per 100 parts by weight. Components other than (a), (b), and (c), for example, ordinary polyvinyl alcohol-based polymers and polyamide-based polymers, may be used without departing from the scope of the present invention.

The photosensitive composition of the present invention may contain a known thermal polymerization inhibitor or storage stabilizer for the purpose of improving the storage stability. If necessary, a coloring agent, a pigment,
Other additives such as a plasticizer may be contained.

[0018]

The photosensitive composition of the present invention has a smaller amount of the polyvinyl alcohol-based polymer in the hardened portion during the washing and development than the one using the polyvinyl alcohol polymer used so far. It is very good. A photosensitive material comprising a polyvinyl alcohol-based polymer, a polymerizable monomer and a photopolymerization initiator is such that the monomer is polymerized by light irradiation and becomes insoluble in water, but in the case of a conventional polyvinyl alcohol-based polymer, It is considered that since the graft reaction to the polyvinyl alcohol-based polymer hardly occurs during the polymerization, the degree of curing can be relatively easily extracted by washing with water.

On the other hand, in the present invention, by introducing a radically polymerizable ethylenic double bond into the polyvinyl alcohol-based polymer, a graft product or a block product is formed during photopolymerization, and the polyvinyl alcohol-based polymer is produced. It is presumed that the above-mentioned effects were obtained by lowering the water solubility and suppressing the phase separation accompanying the polymerization of the monomer due to the formation of the graft and the block.

[0020]

EXAMPLES Hereinafter, the water-soluble photosensitive composition of the present invention will be described with reference to examples, but the present invention is not limited thereto. “Parts” and “%” mean “parts by weight” and “% by weight”, respectively, unless otherwise specified.

Synthesis Example 1 Synthesis Example of a Polyvinyl Alcohol-Based Polymer Having an Ethylenic Double Bond Capable of Radical Polymerization in the Molecule In the structural unit represented by the following Chemical Formula 3, R ¹ =
An amino-modified polyvinyl alcohol containing 3 mol% of a structural unit of H, R ² = CH _{3 and} having a saponification degree of 99.9 mol% and a polymerization degree of 2,000 (units other than the structural unit having an amino group and the vinyl alcohol unit are vinyl acetate; The same applies to the following Example 2) 150 g of dimethyl sulfoxide 4
The mixture was added to 850 g, heated at 90 ° C., and dissolved by stirring.

[0022]

Embedded image (However, R ¹ represents hydrogen or a methyl group, and R ² represents hydrogen or an alkyl group having 1 to 4 carbon atoms.)

After dissolving the amino group-modified polyvinyl alcohol, 82 g of glycidyl methacrylate and 1.6 g of triethylamine were added and reacted at 90 ° C. After 15 hours from the start of the reaction, the stirring was stopped, and the reaction solution was poured into a large amount of acetone,
The polymer is reprecipitated, washed sufficiently, and then dried in a vacuum to contain 2.5 mol% of a structural unit having an ethylenic double bond, to obtain a polyvinyl alcohol polymer having a saponification degree of 99.9 mol% and a polymerization degree of 1970. Obtained.

Example 1 A polyvinyl alcohol polymer having an ethylenic double bond capable of undergoing radical polymerization in a molecule synthesized according to Synthesis Example 1 (polymerization degree 310, saponification degree 88 mol%, ethylenic double bond 100 parts β-oxyethyl methacrylate 90 parts Ethylene glycol dimethacrylate 10 parts Methylhydroquinone 0.05 parts Benzoin isopropyl ether 3 parts Water (pH = 3.0) 200 parts Each of the above components is heated at 90 ° C. in a flask. After defoaming the uniformly dissolved solution while stirring, it was applied on an aluminum plate and dried at 80 ° C. for 30 minutes to obtain a 0.5 mm thick film. Subsequently, a high-pressure mercury lamp was irradiated from a distance of 75 cm for 10 minutes to obtain a cured film.

Example 2 As a polyvinyl alcohol-based polymer, a polyvinyl alcohol-based polymer having a radically polymerizable ethylenic double bond group in the molecule (polymerization degree: 550, saponification degree: 99.9 mol%,
A cured film was obtained in the same manner as in Example 1 except that 2.50 mol% of an ethylenic double bond group was used.

Example 3 As a polyvinyl alcohol-based polymer, a polyvinyl alcohol-based polymer having a radically polymerizable ethylenic double bond group in the molecule (degree of polymerization 2400, degree of saponification 75 mol%,
A cured film was obtained in the same manner as in Example 1 except that ethylenic double bond groups (20 mol%) were used.

Comparative Example 1 A cured film was obtained in the same manner as in Example 1 except that unmodified polyvinyl alcohol (polymerization degree: 550, saponification degree: 88 mol%) was used as the polyvinyl alcohol-based polymer. Comparative Example 2 A cured film was obtained in the same manner as in Example 1 except that unmodified polyvinyl alcohol (polymerization degree: 550, saponification degree: 80 mol%) was used as the polyvinyl alcohol-based polymer.

The cured films obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were immersed in hot water at 90 ° C. for 2 hours, and the weight of the polyvinyl alcohol polymer extracted into the hot water was examined. Table 1 shows the results
Are shown together.

Table 1 Extraction rate (%) of polyvinyl alcohol polymer * Example 1 5.0 Example 2 2.1 Example 3 1.5 Comparative Example 160 Comparative Example 2 81 *: Reduction in weight of cured film The extraction rate was calculated as the weight loss of the polyvinyl alcohol polymer.

As is clear from Table 1, in the case of using a polyvinyl alcohol-based polymer having an ethylenic double bond capable of undergoing radical polymerization in the molecule, the polyvinyl alcohol-based polymer hardly drops from the cured film.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-2757 (JP, A) JP-A-2-8849 (JP, A) JP-A-62-267302 (JP, A) JP-A-49-267 4738 (JP, A) JP-A-48-689 (JP, A) JP-A-64-29836 (JP, A) JP-A-62-146902 (JP, A) JP-A-60-46550 (JP, A) JP-A-58-88742 (JP, A) JP-B-59-17730 (JP, B2) JP-B-63-48328 (JP, B2) JP-B-1-32971 (JP, B2) (58) (Int.Cl. ⁶ , DB name) G03F 7/038 501 G03F 7/00 502 G03F 7/027 501

Claims (1)

(57) [Claims] 1. A (a) have a radical polymerizable ethylenic double bond in the molecule, the ethylene double bond of the following
A polyvinyl alcohol-based polymer which is a structural unit represented by Chemical Formula 1 or Chemical Formula 2 , (b) an unsaturated compound having a radically polymerizable ethylenic double bond, and (c) A photosensitive composition comprising a photopolymerization initiator. Embedded image (However, R ¹ is hydrogen or a methyl group, R ² is hydrogen or an alkyl group having 1 to 4 carbon atoms, R ³ is hydrogen or an alkyl group having 1 to 3 carbon atoms, (X) is A linking group represented by (X ₁ ) linked to a carbon constituting a heavy bond, a linking group represented by (X ₂ ) linked to a carbon constituting a double bond on the R ⁷ side, or a double bond on the O side Link to the carbons that make up the bond
A linking group represented by (X ₃ ), (X ₁ ): -R ⁵ -OC- (R ⁵ is an optionally branched alkylene group having 1 to 20 carbon atoms) O (X ₂ ): —R ⁶ —O—R ⁷ — (R ⁶ and R ⁷ are alkylene groups having 1 to 10 carbon atoms) (X ₃ ): —R ⁶ —O— (R ⁶ is an alkylene group having 1 to 10 carbon atoms) ) Are shown. ) (However, R ¹ is hydrogen or a methyl group, R ² is hydrogen or an alkyl group having 1 to 4 carbon atoms, R ³ is hydrogen or an alkyl group having 1 to 3 carbon atoms, and R ⁴ is an alkylene group having 1 to 3 carbon atoms. , (X)
Is a linking group represented by (X ₁ ) linked to the carbon constituting the double bond on the ester bond side, and represented by (X ₂ ) linked to the carbon constituting the double bond on the R ⁷ side A linking group or a linking group represented by (X ₃ ) linked to a carbon constituting a double bond on the O side (X ₁ ): -R ⁵ -OC- (R ⁵ may have a branch good 1-20 ‖ alkylene group having _{carbon) O (X 2): -R} 6 -O-R 7 - (R 6 and R ⁷ is an alkylene group having 1 to 10 carbon atoms) (X _3): -R ⁶ —O— (R ⁶ represents an alkylene group having 1 to 10 carbon atoms). )