In depth curing of resins induced by UV radiation
AssigneeWestinghouse Electric Corp.
InventorGeorge D. Dixon
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Abstract
A composition is prepared of a liquid vinyl monomer, a UV-activated photo-initiator, a thermal initiator, and an accelerator. The composition also preferably contains a free-radical scavenger and a vinyl oligomer. Upon exposure to ultraviolet light the photo-initiator initiates polymerization in the surface layer thereby generating sufficient heat to activate the thermal initiator and cause the polymerization to proceed throughout the bulk of the monomer.
Claims23
A solventless liquid resinous composition curable with ultraviolet light without externally applied heat, comprising:
- (1) a liquid monomer having the general formula CH.sub.2 .dbd.CHR where R is an electron-withdrawing organic group;
- (2) about 0.01 to about 4% by weight of a photo-initiator capable of initiating the polymerization of said monomer when exposed to ultraviolet light;
- (3) about 0.01 to about 4% by weight of a thermal-initiator capable of initiating the polymerization of said monomer when activated by the exothermic heat of polymerization, said thermal-initiator being a different compound than said photo-initiator;
- and
- (4) about 0.01 to about 0.5% by weight of an accelerator capable of lowering the temperature at which said thermal-initiator is activated by heat.
A method of making a cured vinyl addition polymer without using an external source of heat comprising preparing a composition which comprises:
- (1) a liquid monomer having the general formula CH.sub.2 .dbd.CHR where R is an electron-withdrawing organic group;
- (2) about 0.01 to about 4% by weight of a photo-initiator capable of initiating the polymerization of said monomer when exposed to ultraviolet light;
- (3) about 0.01 to about 4% by weight of a thermal-initiator capable of initiating the polymerization of said monomer when activated by the exothermic heat of polymerization, said thermal-initiator being a different compound than said photo-initiator;
- (4) about 0.01 to about 0.5% by weight of an accelerator capable of lowering the temperature at which said thermal-initiator is activated by heat;
- and exposing said composition to ultraviolet light.
Dependencies are inferred from the claim text.