UV curable elastomer composition

DETAILED DESCRIPTION OF THE INVENTION The thermally stable, curable compositions of the present invention comprise an elastomer; a multifunctional crosslinking agent, generally an acrylic or methacrylic crosslinking agent; and a UV initiator.
These curable compositions are utilized as starting materials in the process for applying a seal to an article that is a further embodiment of the invention.
In preferred embodiments of the process of the invention, the elastomer, multifunctional crosslinking agent and UV initiator are present as three separate components.
However, the UV initiator may be present as a chemically combined component with the elastomer.
That is, the UV initiator may be chemically incorporated into the elastomeric component as a polymer-bound photoinitiator.
Such polymer-bound photoinitiators are disclosed, for example in U.
S.
Pat.
No.
5,128,386 wherein a photoinitiator is copolymerized with an acrylate copolymer.
The compositions are curable by the action of UV radiation.
They are thermally stable at temperatures used to process uncured elastomer formulations, e.
g.
in mixing or extruding operations.
Such temperatures generally range from 25.
degree.
C.
to 250.
degree.
C.
By thermally stable is meant that the compositions do not spontaneously form a crosslinked network, i.
e.
they do not prematurely cure or scorch.
That is, the viscosity of the compositions remains constant, within .
+-.
50% of the initial value when heated to the processing temperature, as indicated by lack of a substantial increase in torque (i.
e.
an increase of less than 1 dNm) when subjected to the processing temperature for 30 minutes in a Moving Die Rheometer.
The appropriate processing temperature will depend on the decomposition temperature of the particular UV initiator and multifunctional crosslinking agent that is employed.
However, the processing temperature must be sufficiently high so that the curable elastomer composition flows to the degree required for the production process.
This temperature will generally be from 25