Thiol-ene-curing compositions

1. A curable composition, comprising:

(A) one or more compounds having two or more olefinically unsaturated functional groups and at least one silyl group which is prepared by

(i) reacting a polyisocyanate (D) having three or more isocyanate groups, with one or more silyl functional compounds (C) having at least one isocyanate-reactive functional group, in a molar ratio that provides for remaining isocyanate groups, and subsequently reacting the reaction product of the polyisocyanate (D) and the silyl functional compound(s) (C) having at least one isocyanate-reactive functional group with one or more compounds (E) having at least one olefinically unsaturated functional group and at least one isocyanate-reactive functional group, or

(ii) reacting first the polyisocyanates (D) with one or more compounds (E) having at least one olefinically unsaturated functional group and at least one isocyanate-reactive functional group, and then reacting the reaction product of compound (D) and (E) with the silyl functional compound(s) (C), and

(B) at least one polythiol.

2. The curable composition according to claim 1 , comprising one or more curing catalysts.

3. The curable composition according to claim 1 , wherein the polythiol (B) is selected from compounds of the formula (I):

R 1 —(SH) n   (I)

wherein R 1 is an organic residue and n is an integer of at least 2.

4. The curable composition of claim 3 , wherein the polythiol (B) is selected from the group consisting of pentaerythritol tetrakis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), and tris[2-(3-mercaptopropionyloxy)ethyl] isocyanurate.

5. The curable composition according to claim 1 , wherein the compounds having two or more olefinically unsaturated functional groups and at least one silyl group (A) are of the formula (III):

(R 4 ) x —R 5 —(R 6 ) y   (III)

wherein

R 4 is an olefinically unsaturated functional group,

R 5 is an (x+y)-valent organic residue,

R 6 is a silyl group,

x is an integer of at least 2, and

y is an integer of at least 1.

6. The curable composition according to, claim 1 , wherein the polyisocyanates (D) are of the formula (IV):

R 7 —(NCO) z   (IV)

wherein R 7 is a z-valent organic residue and z is at least 3.

7. The curable composition according to claim 1 , wherein the one or more silyl functional compounds (C) having at least one isocyanate-reactive functional group are of the formula (V):

(R 8 ) v —R 9 —(R 6 ) w   (V)

wherein

R 8 is an isocyanate-reactive functional group,

R 9 is a (v+w)-valent organic residue,

R 6 is a silyl group which is capable of forming Si—O—Si crosslinks upon exposure to moisture,

v is an integer of 1 or 2, and

w is an integer of 1 or 2.

8. The curable composition of claim 7 , wherein R 8 is an amino group.

9. The curable composition according to claim 1 , wherein the one or more compounds (E) having at least one olefinically unsaturated functional group and at least one isocyanate-reactive functional group are of the formula (VI):

(R 10 ) c —R 11 —(R 4 ) d   (V)

wherein

R 10 is an isocyanate-reactive functional group,

R 11 is an aliphatic (c+d)-valent residue,

R 4 is an olefinically unsaturated functional group,

c is an integer of 1 or 2, and

d is an integer of 1 or 2.

10. The curable composition of claim 9 , wherein R 10 is a hydroxy group.

11. The curable composition according to claim 1 , wherein the one or more compounds (E) having at least one olefinically unsaturated functional group and at least one isocyanate-reactive functional group are selected from hydroxyl-functional (meth)acrylic monomers.

12. The curable composition of claim 11 , wherein the one or more compounds (E) having at least one olefinically unsaturated group and at least one isocyanate-reactive functional group are selected from hydroxyalkyl(meth)acrylic monomers.

13. The composition of claim 1 , wherein the polythiol (B), comprises at least one silyl group.

14. A method of coating a substrate comprising applying the curable composition according to claim 1 to said substrate and curing the curable composition.

15. A cured composition obtained by curing the curable composition according to claim 1 .

16. A cured article, comprising the cured composition according claim 15 .

17. A curable composition, comprising:

(A′) one or more compounds (A-1) having two or more olefinically unsaturated functional groups and at least one silyl functional group, which compound (A-1) is formed by (1) the reaction of a silyl functional compound (C) having at least one isocyanate-reactive functional group, with a polyisocyanate (D) having three or more isocyanate groups, in a molar ratio that provides for remaining isocyanate groups, followed by the reaction of the reaction product of (C) and (D) with a compound (E) having at least one olefinically unsaturated functional group and at least one isocyanate-reactive functional group or (2) reacting the polyisocyanate (D) with the compound (E) followed by the reaction of the reaction product of (D) and (E) with the silyl functional compound (C), and

(B) at least one polythiol comprising at least one silyl group.