Radiation-curable coating composition

1. Radiation-curable composition comprising:

(A) a urethane (meth)acrylate oligomer comprising an alkyd backbone, said alkyd backbone being derived from a polyester, said polyester having pendant ester groups protruding off of a main polymer chain of ester linkages, said pendant ester groups being derived from a compound selected from the group consisting of coconut oil, palm Kernel oil, and hydrogenated varieties of unsaturated oils or fatty acids having an Iodine value below 100 centigrams Iodine I gram sample;

(B) a reactive diluent; and

(C) a photoinitiator

wherein said composition, when cured, has a hydrolysis resistance of less than 30% loss in equilibrium modulus after 30 days exposure at 85° C. and 85% relative humidity.

2. The composition of claim 1 , wherein said hydrolysis resistance is less than 20%.

3. The composition of claim 1 , wherein said composition, when cured, has a dynamic water sensitivity of less than 2%.

4. The composition of claim 1 , wherein said composition,when cured, has a dynamic water sensitivity of less than 1.6%.

5. The composition of claim 1 , wherein said composition, when cured, has a ΔE yellowing resistance, after exposure to 125° C. for 8 weeks, of less than 60.

6. The composition of claim 1 , wherein said composition comprises, relative to the total weight of the composition, 15–80 wt % of said oligomer.

7. The composition of claim 1 , wherein said composition, when cured, has a dynamic oil sensitivity of less than 1.2%.

8. The composition of claim 1 , wherein said alkyd has an average hydroxyl functionality between 1.5 and 5.

9. Radiation-curable composition comprising:

(A) a urethane (meth)acrylate oligomer comprising an alkyd backbone, said alkyd backbone derived from a polyfunctional alcohol, a polyfunctional carboxylic acid and a monocarboxylic fatty acid, and wherein the polyfunctional carboxylic acid compound is at least one compound selected from the group consisting of adipic acid, orthophthalic acid, isophthalic acid, and terephthalic acid, and the polyfunctional alcohol compound is at least one compound selected from the group consisting of glycerol, trimethylol propane, trimethylol ethane, pentaerythritol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and hydroxypivaloyl hydroxy pivalate, said alkyd backbone having pendant ester groups protruding off of a main polymer chain of ester linkages, said pendant ester groups being derived from long chain monocarboxylic fatty acids having an Iodine value below 100 centigrams iodine/gram sample;

(B) a reactive diluent; and

(C) a photoinitiator;

wherein said composition, when cured, has a hydrolysis resistance of less than 30% loss in equilibrium modulus after 30 days exposure at 85° C. and 85% relative humidity.

10. The composition of claim 9 , wherein said hydrolysis resistance is less than 20%.

11. The composition of claim 9 , wherein said composition, when cured, has a dynamic water sensitivity of less than 2%.

12. The composition of claim 9 , wherein said monocarboxylic fatty acid has between 12 and 28 carbon atoms.

13. The composition of claim 9 , wherein said alkyd has an average hydroxyl functionality between 1.5 and 5.

14. Radiation-curable composition comprising:

(A) a urethane (meth)acrylate oligomer comprising an alkyd backbone, said alkyd backbone being derived from a polyester derived from a polyol selected from the group consisting of trialcohol alkanes and pentaerythritol, a polyacid, and a monocarboxylic fatty acid; said polyester having pendant ester groups protruding off of a main polymer chain of ester linkages, said pendant ester groups being derived from said monocarboxylic fatty acids having an Iodine value below 100 centigrams iodine/gram sample;

(B) a reactive diluent; and

(C) a ohotoinitiator;

wherein said composition, when cured, has a hydrolysis resistance of less than 30% loss in equilibrium modulus after 30 days exposure at 85° C. and 85% relative humidity.

15. The composition of claim 14 , wherein said hydrolysis resistance is less than 20%.

16. The composition of claim 14 , wherein said composition, when cured, has a dynamic water sensitivity of less than 2%.

17. The composition of claim 14 , wherein said alkyd has an average hydroxyl functionality between 1.5 and 5.

18. A coated optical fiber with a coating obtained by curing a composition according to claim 14 .

19. The composition of claim 14 , wherein said composition is an inner primary coating composition, an outer primary coating composition, a matrix material composition, an ink composition, or a bundling material composition.

20. The composition of claim 14 , wherein said composition, when cured, has a dynamic water sensitivity of less than 1.2%.