Uv-curable and foamable resin composition

1. A process for preparing a UV-cured foam by irradiating UV light to a composition comprising: (A) a photolytic foaming agent selected from an azo compound, a combination of a sulfonium salt and an inorganic carbonate, and a mixture thereof, (B) a photopolymerizable urethane acrylate oligomer, (C) a photopolymerizable monomer, (D) a photopolymerization initiator, and (E) a photolysis catalyst.

2. The process of claim 1 , wherein the composition comprises (A) 0.1 to 20 wt % of a photolytic foaming agent, (B) 45 to 80 wt % of a photopolymerizable urethane acrylate oligomer, (C) 15 to 50 wt % of a photopolymerizable monomer, (D) 0.01 to 5 wt % of a photopolymerization initiator, and (E) 0.01 to 5 wt % of a photolysis catalyst, the weight percent being based on the total amount of the composition.

3. The process of claim 1 , wherein the azo compound is selected from the group consisting of 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobisisobutyronitrile, dimethyl 2,2-azobisisobutyrate, 2,2-azobis(2-methylbutyronitrile), 1,1-azobis(1-cyclohexanecarbonitrile), 2-(carbamoylazo)-isobutyronitrile, 2,2-azobis(2,4,4-trimethylpentane), 2,2-azobis(N,N-dimethyleneisobutylamidine)dihydrochloride, 2,2-azobis(2-aminopropane)dihydrochloride, 2,2-azobis(N,N-dimethyleneisobutylamide), 4,4-azobis[2-methyl-N-(2-hydroxyl)propionamide], azobenzene, azobis-tert-butane, and a mixture thereof.

4. The process of claim 1 , wherein the sulfonium salt is selected from the group consisting of compounds of formulas, and the inorganic carbonate is selected from the group consisting of calcium carbonate, sodium bicarbonate and potassium carbonate:

5. The process of claim 1 , wherein the photolysis catalyst is cobalt(II) acetate or copper(II) acetate.

6. The process of claim 1 , wherein the composition is coated on an optical article.

7. The process of claim 6 , wherein the optical article is a fiber bundle applied to an air blown fiber system.