Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
1999-05-25
2001-09-18
Hamilton, Cynthia (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C522S090000, C522S096000, C522S097000
Reexamination Certificate
active
06291133
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a photosensitive resin composition, and more particularly to a photosensitive resin composition suitable for a plate for aqueous flexography and a resin plate for flexography using the photosensitive resin composition.
TECHNICAL BACKGROUND
Conventionally, thermoplastic elastomers having appropriate impact resilience or photosensitive resin compositions comprising photopolymerizable unsaturated monomers and photopolymerization initiators have been used as photosensitive resin compositions for forming photosensitive resin layers of photosensitive resin plates for flexography. As the above-mentioned thermoplastic elastomers, for example, styrenic resins such as styrene/isoprene/styrene and styrene/butadiene/styrene have been used. However, these thermoplastic elastomers are hydrophobic, so that they can not be extracted with water or aqueous solvents. Accordingly, chlorine series organic solvents such as chloroform, trichloroethane, trichloroethylene and tetrachloroethylene have been exclusively used. Such chlorine series organic solvents have no inflammability, are easy in handling and high in stability. However, they are highly toxic to the human body, which not only raises a problem with regard to hygiene, but also are unfavorable from the viewpoint of working environment.
For solving such a problem of the conventional photosensitive resin compositions, water-soluble photosensitive resin compositions containing polyvinyl alcohol or water-soluble nylon as a resin component have been proposed. However, they are low in impact resilience, so that they are unsuitable as materials for printing plates for printing thick printing materials such as corrugated fiberboards. Moreover, they have the disadvantage that water-color ink can not be used. Then, the present inventors have proposed a photosensitive resin composition comprising a resin obtained by reacting a carboxyl group-containing polymer having an acid value of 30 mg KOH/g or more and a glass transition temperature of 30° C. or more, a compound having two isocyanate groups in one molecule and a compound having two hydroxyl groups in one molecule as indispensable components, a photopolymerizable unsaturated monomer, and a photopolymerization initiator, as a photopolymerization initiator-containing photosensitive resin composition having water developing properties and excellent in impact resilience, in JP-A-8-36263 (the term “JP-A” as used herein means an “unexamined published Japanese patent publication”). The above-mentioned photosensitive resin composition has water developing properties and are excellent in impact resilience. However, it has the problems that a hardened portion forming a line pattern portion of a printing plate material is poor in water resistance, that the ink resistance is low, and moreover that the press life is also poor.
However, the photosensitive resin composition described in JP-A-8-36263 has excellent characteristics of water developing properties and high impact resilience which no conventional photosensitive resins have. Accordingly, based on the idea that an excellent photosensitive resin composition will be obtained by modifying the above-mentioned photosensitive resin composition described in JP-A-8-36263, the present inventors have made intensive studies. As a result, the inventors have discovered that a resin obtained by reacting a carboxyl group-containing polymer which has an acid value of 30 mg KOH/g or more and a glass transition temperature of 30° C. or more, a compound having two isocyanate groups in one molecule, a compound having two hydroxyl groups in one molecule and a photopolymerizable unsaturated monomer having one hydroxyl group in one molecule is effective as the resin component of the photosensitive resin composition, thus completing the present invention.
It is therefore an object of the present invention to provide a photosensitive resin composition having water developing properties and high sensitivity.
Furthermore, another object of the present invention is to provide a resin plate for flexography which has excellent impact resilience and is excellent in water resistance, ink resistance and press life of the line pattern area.
DISCLOSURE OF THE INVENTION
The invention which achieves the above objects is described below as items (1) to (11).
(1) A photosensitive resin composition comprising an urethane resin obtained by reacting (A) a carboxyl group-containing polymer having an acid value of 30 mg KOH/g or more and a glass transition temperature of 30° C. or more, (B) a compound having two isocyanate groups in one molecule, (C) a compound having two hydroxyl groups in one molecule and (D) a photopolymerizable unsaturated monomer having one hydroxyl group in one molecule, and a photopolymerization initiator.
(2) A photosensitive resin composition comprising an urethane resin obtained by reacting (A) a carboxyl group-containing polymer having an acid value of 30 mg KOH/g or more and a glass transition temperature of 30° C. or more, (B) a compound having two isocyanate groups in one molecule, (C) a compound having two hydroxyl groups in one molecule and (D) a photopolymerizable unsaturated monomer having one hydroxyl group in one molecule, and a photopolymerizable unsaturated monomer and a photopolymerization initiator.
(3) A photosensitive resin composition comprising an urethane resin comprising as structural units (A) a carboxyl group-containing polymer having an acid value of 30 mg KOH/g or more and a glass transition temperature of 30° C. or more, (B) a compound having two isocyanate groups in one molecule, (C) a compound having two hydroxyl groups in one molecule and (D) a photopolymerizable unsaturated monomer having one hydroxyl group in one molecule, and a photopolymerization initiator.
(4) The photosensitive resin composition according to any one of the above items (1) to (3), wherein the urethane resin is a resin obtained by reacting component (B), component (C), component (D) and component (A) in this order.
(5) The photosensitive resin composition according to any one of the above items (1) to (4), wherein component (A) is an acrylic polymer.
(6) The photosensitive resin composition according to any one of the above items (1) to (4), wherein component (B) is hexamethylene diisocyanate.
(7) The photosensitive resin composition according to any one of the above items (1) to (5), wherein component (C) is polyether diol.
(8) The photosensitive resin composition according to any one of the above items (1) to (4), wherein component (D) is a hydroxyl group-containing unsaturated acrylic acid ester series monomer.
(9) The photosensitive resin composition according to the above item (8), wherein the hydroxyl group-containing unsaturated acrylic acid ester series monomer is 2-hydroxyethyl acrylate.
(10) A resin plate for flexography using the photosensitive resin composition of any one of the above items (1) to (9).
(11) A resin plate for flexography, which uses the photosensitive resin composition of any one of the above items (1) to (9) and has a photosensitive resin layer having an impact resilience of 30% or more according to JIS K6301-11.
BESE MODE TO CARRY OUT THE INVENTION
The present invention will be described below in detail.
There is no particular limitation on component (A) used in the photosensitive resin composition of the present invention, as long as it is a carboxyl group-containing polymer having an acid value of 30 mg KOH/g or more and a glass transition temperature of 30° C. or more. There is also no particular limitation on a method for producing it, and it can be produced by any known method. Examples thereof include a method of copolymerizing a carboxyl group-containing monomer with an unsaturated monomer. Specific examples of the above-mentioned carboxyl group-containing monomers include acrylic acid, methacrylic acid, maleic acid, maleic monoester, fumaric acid, fumaric monoester, itaconic acid, itaconic monoester and cinnamic acid. The above-mentioned carboxyl group-containing mono
Aoyama Toshimi
Kahara Koji
Kobayashi Nobuhiro
Takagi Toshiya
Yoshida Masatoshi
Fish & Richardson P.C.
Hamilton Cynthia
Tokyo Ohka Kogyo Co. Ltd.
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