Abstract: A high-strength zinc base alloy which contains 5.2 to 8.6 wt % of Al, 3.0 to 6.5 wt % of Cu, 0.01 to 0.20 wt % of Mg, and if necessary, 0.30 wt % or less of one or two of Co and Ni, and/or 0.04 wt % or less of Ti, the balance being substantially composed of Zn, and which is suitable for a metal mold and die casting.

Abstract: An optical information recording medium is disclosed, which comprises a plastic substrate; an undercoat layer formed thereon, comprising a condensate of a mixture of (1) at least one metal alcoholate selected from the group consisting of a tetra-alkoxy metal and an organic tri-alkoxy metal, and (2) a polymeric compound selected from the group consisting of (i) a copolymer of an acrylate or methacrylate containing at least one hydroxy alkyl group, and an acrylate or methacrylate containing an alkyl group, and (ii) an amino-group-containing polymer; and a recording layer formed on the undercoat layer.

Abstract: 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.

Abstract: A color-developing sheet for use in no-carbon copying system, which contains a layer of a combination of a solid acid with an acidic polymer is improved in preventing yellowing during the preservation thereof, in giving high color intensity and stability to image formed, by incorporating titanium dioxide into the layer.

Abstract: 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.