Solventless, ultraviolet radiation-curable silicone coating compositions
AssigneeGeneral Electric Company
InventorRack H. Chung
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Abstract
An ultraviolet radiation-curable silicone coating composition is disclosed which, when applied to a solid substrate, provides an abrasion-resistant coating firmly adhered thereon. The silicone coating composition is free of residual solvent and free of toxic hydroxy acrylates, and is prepared from the hydrolysis products of acryloxy-functional silanes and/or glycidoxy-functional silanes, colloidal silica and a photoinitiator.
Claims30
A solventless ultraviolet radiation-curable coating composition free of hydroxy acrylates comprising:
- (A) 100 parts by weight silica in the form of a colloidal dispersion;
- (B) 5 to 500 parts by weight of an acid hydrolysis product of
- (i) an acryloxy-functional silane having a general formula:
- ##STR9## wherein R.sup.3 and R.sup.4 are the same or different monovalent hydrocarbon radicals, R.sup.5 is a divalent hydrocarbon radical having from 2 to 8 carbon atoms, R.sup.6 is hydrogen or a monovalent hydrocarbon radical, b is an integer from 1 to 3, c is an integer from 0 to 2, and d is an integer equaling 4-b-c;
- or
- (ii) a glycidoxy-functional silane having a general formula:
- ##STR10## wherein R.sup.7 and R.sup.8 are the same or different monovalent hydrocarbon radicals, R.sup.9 is a divalent hydrocarbon radical having from 2 to 8 carbon atoms, e is an integer from 1 to 3, f is an integer from 0 to 2, and g is an integer equaling 4-e-f;
- or
- (iii) a mixture of (i) and (ii);
- and
- (C) a catalytic amount of an ultraviolet light sensitive photoinitiator or mixture of photoinitiators;
- wherein residual solvent has been removed from said coating composition at reduced pressure.
A process for preparing a solventless ultraviolet radiation curable coating composition free of hydroxy acrylates comprising:
- (1) Combining
- (A) 100 parts by weight silica in the form of a colloidal dispersion;
- (B) 5 to 500 parts by weight of the acid hydrolysis product of
- (i) an acryloxy-functional silane of the formula:
- ##STR13## wherein R.sup.3 and R.sup.4 are the same or different monovalent hydrocarbon radicals, R.sup.5 is a divalent hydrocarbon radical having from 2 to 8 carbon atoms, R.sup.6 is hydrogen or a monovalent hydrocarbon radical, b is an integer from 1 to 3, c is an integer from 0 to 2, and d is an integer equal to 4-b-c;
- or
- (ii) a glycydoxy-functional silane of the formula:
- ##STR14## wherein R.sup.7 and R.sup.8 are the same or different monovalent hydrocarbon radicals, R.sup.9 is a divalent hydrocarbon radical having from 2 to 8 carbon atoms, e is an integer from 1 to 3, f is an integer from 0 to 2, and g is an integer equal to 4-e-f;
- or
- (iii) mixtures of (i) and (ii);
- (2) adding a catalytic amount of an ultraviolet light sensitive photoinitiator;
- and thereafter
- (3) removing residual solvent at reduced pressure.
Dependencies are inferred from the claim text.