lichthaertbare kunststoffmassen and manufactured printing plates

摘要

1,251,232. Photocurable compositions. W. R. GRACE & CO. 10 Oct., 1968 [12 Oct., 1967], No. 48122/68. Headings C3P and C3R. [Also in Division G2] A photocurable composition comprises (1) a polyene containing at least 2 unsaturated carbon-to-carbon bonds per molecule and (2) a polythiol containing at least 2 thiol groups per molecule, the total combined functionality of the composition i.e. the number of unsaturated carbon-to-carbon bonds per molecule plus the number of thiol groups per molecule being greater than 4. A number of such compositions are disclosed in U.K. Specification 1,215,591. In specific Examples, the polyene is derived from (a) a polyurethane prepolymer and allyl alcohol, (b) a polyether, polyisocyanate and allyl alcohol in a single stage, (c) a polyether or polyester and allyl isocyanate, (d) a polyether, polyisocyanate and allyl isocyanate or maybe a styrene-butadiene rubber. The polythiol may be pentaerythritol tetrakis (#-mercaptopropionate), ethylene glycol bis(#-mercaptopropionate) or trimethylolpropane tris- (beta-mercaptopropionate). The compositions may be used in image reproduction processes (see Division G2).