UV curable elastomer composition
View Patent ↗Ethylene copolymer elastomer compositions, acrylate rubber compositions, nitrile rubber compositions, fluoroelastomer compositions, and chlorinated olefin elastomer compositions are provided which are curable by exposure to UV radiation. The compositions are particularly suited for production of elastomeric seals using hot melt equipment and a gasketing in place technique.
1. A thermally stable, UV curable elastomer composition, thermally stable at temperatures of 25 ° C.- 250 ° C., comprising
A) 70 to 99 weight percent of a fluoroelastomer having at least one cure site selected from the group consisting of 1) copolymerized brominated olefins, chlorinated olefins and iodinated olefins; 2) copolymerized brominated unsaturated ethers, chlorinated unsaturated ethers, and iodinated unsaturated ethers; 3) copolymerized non-conjugated dienes and trienes and 4) iodine atoms and bromine atoms and mixtures thereof that are present at terminal positions of the fluoroelastomer chain;
B) 0.5 to 20 weight percent of a multifunctional crosslinking agent selected from the group consisting of multifunctional acrylic crosslinking agents, multifunctional methacrylic crosslinking agents, multifunctional cyanurate crosslinking agents, and multifunctional isocyanurate crosslinking agents; and
C) 0.1 to 10 weight percent of a UV initiator
wherein the elastomer composition does not comprise a heat- activated heterolytic cure system or a homolytic peroxide cure system; and wherein the weight percentages of each of components A), B), and C) are based on the combined weight of components A), B), and C).
2. The composition of claim 1 wherein the fluoroelastomer is a copolymer comprising copolymerized units of vinylidene fluoride.
3. The composition of claim 1 wherein the fluoroelastomer is a copolymer comprising copolymerized units of tetrafluoroethylene.
4. The composition of claim 1 wherein the cure site is selected from the group consisting of copolymerized brominated olefins, chlorinated olefins and iodinated olefins.
5. The composition of claim 1 wherein at least one cure site is selected from the group consisting of copolymerized brominated unsaturated ethers, chlorinated unsaturated ethers, and iodinated unsaturated ethers.
6. The composition of claim 1 wherein at least one cure site is selected from the group consisting of copolymerized non-conjugated dienes.
7. The composition of claim 1 wherein at least one cure site is selected from the group consisting of iodine atoms and bromine atoms and mixtures thereof that are present at terminal positions of the fluoroelastomer chain.
8. The composition of claim 1 having a cure site that is a brominated olefin.
9. The composition of claim 8 wherein the cure site is 4-bromo-3,3,4,4-tetrafluoro-1-butene.
10. The composition of claim 1 wherein the multifunctional crosslinking agent is a multifunctional acrylic crosslinking agent.
11. The composition of claim 1 wherein the multifunctional crosslinking agent is a multifunctional methacrylic crosslinking agent.
12. The composition of claim 1 wherein the UV initiator is a ketone.
13. The composition of claim 1 wherein the multifunctional crosslinking agent is a multifunctional cyanurate crosslinking agent.
14. The composition of claim 1 wherein the multifunctional crosslinking agent is a multifunctional isocyanurate crosslinking agent.
15. The composition of claim 4 wherein the cure site is an iodinated olefin.
16. The composition of claim 15 wherein the iodinated olefin is 4 - iodo - 3 , 3 , 4 , 4 - tetrafluorobutene - 1 .