Asahi Kasei Kogyo Kabushiki Kaisha

Kiichi Iida

Tadashi Kawamoto

Masayoshi Mizuno

Kazuhito Miyoshi

A urethane photosensitive resinous composition composition comprising (a) at least one urethane prepolymer having in the middle of the molecule thereof at least two polyol compound monomer units linked through a diisocyanate compound monomer unit, and having only in the terminals of the molecule thereof at least 1.6 carboxyl groups on the average per molecule and acrylic residues with a vinyl group, each one of said acrylic residues being substantially present in each terminal of the molecule of said at least one urethane prepolymer, (b) at least one ethylenically unsaturated compound, and (c) at least one photopolymerization initiator. If desired, the urethane photosensitive resinous composition may further comprise at least one heat polymerization inhibitor. The photosensitive resinous composition of the present invention, in the process of producing printing plates, is good in developability with aqueous developers and capable of becoming sufficient in mechanical strength upon post exposure to even a small amount of light even in the presence of air, and can provide letterpress printing plates that are substantially free of surface tack and have high resistances to water or moisture and to abrasion and wear and, hence, long printing durability.

Urethane photosensitive resinous composition

A printing plate comprising a support, reliefs formed thereon as an image area, and from about 20 to about 4,000/cm.sup.2 small projections thereon in non-image areas, the height of the reliefs being at least 0.05 mm larger than that of the small projections, and a method for making a printing plate which comprises:

Printing plate and method for forming the same having small projections

A printing plate comprising a support, reliefs formed thereon as an image area, and from about 20 to about 4,000/cm.sup.2 small projections thereon in non-image areas, the height of the reliefs being at least 0.05 mm larger than that of the small projections, and a method for making a printing plate which comprises: A. superimposing a photosensitive resin layer having a thickness of at least 0.06 mm on a support, which is at least semi-transparent to actinic light, in intimate contact therewith; B. exposing the resulting assembly to actinic light through an image-bearing transparency from the side of the photosensitive resin layer; C. exposing the assembly to actinic light through a dot-image-bearing transparency having a transparent halftone dot area in a proportion of 1 to 40% from the side of the support to thereby form reliefs on the support, as image areas, and a number of small projections having a height of at least 0.01 mm and being lower than the height of reliefs, in non-image areas, wherein steps (b) and (c) may be conducted in the order: (b) and then (c); or (c) and then (b); or simultaneously.

Growing community of inventors

Shizuoka, Japan

Kiichi Iida