Somar Manufacturing Co., Ltd.

Somar Corporation

Kunio Morikubo

Kohtaro Nagasawa

Tsutomu Satoh

Fujio Tanaka

Kohtaro Nagazawa

Masaki Okuyama

A light-sensitive composition is described, containing: (A) a light-sensitive diazo compound, (B) a combination of Polymer (B-1) and Polymer (B-2), and (C) an epoxy resin. Polymer (B-1) is a polymer having the structural units of the general formulae (i), (ii) and (iii). Polymer (B-2) is a polymer having the structural units of the general formulae (iv), (v) and (vi). ##STR1## wherein R.sup.1 is a hydrogen atom or a methyl group, R.sup.2 is an unsubstituted or substituted benzyl group, a lower alkyl group, or a halogen-substituted lower alkyl group, R.sup.3 is a hydrogen atom, a lower alkyl group, or a halogen-substituted lower alkyl group, R.sup.4 is a tert- or iso-butyl group, and R.sup.5 is a lower alkyl group. This composition is a negative-type light-sensitive composition and is used to prepare a lithographic printing plate, for example. This printing plate is superior in lipophilic nature and also in mechanical properties such as abrasion resistance.

Light-sensitive negative working composition with diazonium condensate,

A photohardenable material is disclosed. The material is comprised of a copolymer (I') having ethylenically unsaturated bonds and having an acid value of about 5 to 180 and a molecular weight of about 1,500 to 100,000. The copolymer (I') is obtained by reacting carboxyl groups with a copolymer represented by the structural formula (I), as defined within the application. The material is further comprised of a copolymer (II) having a molecular weight of about 50,000 to 500,000. The copolymer (II) is comprised of three monomers whose structural formula is also defined within the application. The material is further comprised of a cross-linking agent having two or more ethylenically unsaturated bonds and a photoactivator. The copolymers (I') and (II) are present in a ratio of about 0.5 to 20.

Photohardenable materials

A photocurable composition comprising a first copolymer having a recurring unit of general formula (I): ##STR1## wherein Ar represents a substituted or unsubstituted phenyl group, R.sub.1 represents a lower alkyl group, and m.sub.1 and m.sub.2 are positive numbers with m.sub.1 being greater than or equal to m.sub.2 ; and a second copolymer having a recurring unit of general formula (II): ##STR2## wherein R.sub.2 represents a lower alkyl group, X represents a hydrogen atom or a methyl group, and R.sub.3 represents an isobutyl group, a t-butyl group or a --CH.sub.2 Ar group where Ar represents a substituted or unsubstituted phenyl group and when R.sub.3 is --CH.sub.2 Ar, R.sub.2 can also be t-butyl and isobutyl, and n.sub.1, n.sub.2 and n.sub.3 are positive numbers but n.sub.1 can be zero and (n.sub.1 +n.sub.2)/n.sub.3 equals to about 0.5 to 20; and containing suitable amounts of a cross-linking agent and a photoactivator.

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Soka, Japan

Kunio Morikubo