Polythiol effect curable polymeric composition

A composition comprising

• (1) about 60 to about 95% by weight of said composition of a C--C unsaturated polymeric acrylonirile resin having a macromolecular structure and being a polyene having a weight average molecular weight of at least about 5,000;
• (2) about 5 to about 30% by weight of material (1) of at least one monomer that is an addition polymerizable polyethylenically unsaturated acrylic or methacrylic acid ester containing two or more acrylate or methacrylate groups per molecule or mixtures thereof having at least one crosslinkable C--C unsaturated bond;
• (3) about 0.01 to about 10% by weight of said acrylonitrile resin of photoinitiator;
• and
• (4) about 0.5 to about 10% by weight of said acrylonitrile resin of polythiol having the general formula R.sub.8 --(-SH).sub.n where n is at least 2 and R.sub.8 is a polyvalent organic moiety free from reactive carbon to carbon unsaturation, said composition curing with a surface of at least a substantially reduced tack compared to the same composition except the polythiol and forming a resilient cured member.

The method of forming a coating on a substrate which comprises applying to the surface of a substrate a layer of a composition comprising

• (1) about 60 to about 95% by weight of said composition of a C--C unsaturated acrylonitrile resin having a macromolecular structure and being a polyene having a weight average molecular weight of at least about 5,000;
• (2) about 5 to about 30% by weight of material (1) of at least one monomer that is an addition photopolymerizable polyethylenically unsaturated acrylic or methacrylic acid ester containing two ore more acrylate or methacrylate groups per molecule or mixtures thereof having at least one radiation crosslinkable C--C unsaturated bond;
• (3) about 0.01 to about 10% by weight of material (1) of photoinitiator;
• and
• (4) about 0.5 to about 10% by weight of material (1) of polythiol having the general formula R.sub.8 --(--SH).sub.n where n is at least 2 and R.sub.8 is a polyvalent organic moiety free from reactive carbon to carbon unsaturation and thereafter exposing the layer to radiation, forming a resilient coating that has a surface having a substnatially reduced tack compared to a printing plate formed from the same composition except the polythiol.

The method of forming a printing plate which comprises

• (A) applying to a polyester film substrate in a coating thickness of about 2 to about 200 mils a radiation curable composition comprising
• (1) about 60 to about 95% by weight of said composition of a C--C saturated polymeric binder having a macromolecular structure and a weight average molecular weight of at least about 5,000;
• (2) about 5 to about 30% by weight of said C--C saturated binder of at least one monomer that is an addition photopolymerizable polyethylenically unsaturated acrylic or methacrylic acid ester containing two or more acrylate or methacrylate groups per molecule or mixtures thereof and having at least one photocrosslinkable C--C unsaturated bond;
• (3) about 0.01 to about 10% by weight of said C--C saturated binder of photoinitiator;
• and
• (4) about 0.5 to about 10% by weight of said C--C saturated binder of polythiol having a general formula R.sub.8 --(--SH).sub.n where n is at least 2 and R.sub.8 is a polyvalent organic moiety free from reactive carbon to carbon unsaturation, said polythiol being limited to an amount that will not basically change the curing properties of the combination of components (1), (2) and (3) of said radiation curable composition;
• (B) Exposing to actinic radiation projected through an image-bearing transparency selected portions of said radiation curable composition for a time sufficient to cure the radiation curable composition in the exposed portions;
• and
• (C) thereafter removing the unexposed radiation curable composition, forming a resilient printing plate that has a surface having a substantially reduced tack compared to a printing plate formed from the same composition except the polythiol.

A composition comprising

• (1) about 60 to about 95% by weight of said composition of a C--C saturated polymeric binder having a macromolecular structure and a weight average molecular weight of at least about 5,000;
• (2) about 5 to about 30% by weight of material (1) of at least one monomer having at least one crosslinkable C--C unsaturated bond;
• (3) about 0.01 to about 10% by weight of said C--C saturated polymeric binder of photoinitiator;
• and
• (4) about 0.5 to about 10% by weight of said C--C saturated binder of polythiol having the general formula R.sub.8 --(--SH).sub.n where n is at least 2 and R.sub.8 is a polyvalent organic moiety free from reactive carbon to carbon unsaturation, said composition curing with a surface of at least a substantially reduced tack compared to the same composition except the polythiol and forming a resilient cured member.

The method of forming a coating on a substrate which comprises applying to the surface of a substrate a layer of a composition comprising

• (1) about 60 to about 95% by weight of said composition of a C--C saturated polymeric binder having a macromolecular structure and a weight average molecular weight of at least about 5,000;
• (2) about 5 to about 30% by weight of said C--C saturated binder of at least one monomer that is an addition photopolymerizable polyethylenically unsaturated acrylic or methacrylic acid ester containing two or more acrylate or methacrylate groups per molecule or mixture thereof having at least one radiation crosslinkable C--C unsaturated bond;
• (3) about 0.01 to about 10% by weight of said C--C saturated polymeric binder of photoinitiator;
• and
• (4) about 0.5 to about 10% by weight of said C--C saturated binder of polythiol having the general formula R.sub.8 --(--SH).sub.n where n is at least 2 and R.sub.8 is a polyvalent organic moiety free from reactive carbon to carbon unsaturation and thereafter exposing the layer to radiation, forming a resilient coating that has a surface having a substantially reduced tack compared to a printing plate formed from the same composition except the polythiol.