Methods for making cured sealants by actinic radiation and related compositions

1. A method for making a cured sealant comprising:

(a) depositing an unreacted sealant composition on a substrate; and

(b) exposing the unreacted sealant composition to actinic radiation to provide a cured sealant, wherein the unreacted sealant composition comprises:

(i) a thiol-terminated polythioether;

(ii) a polyene comprising a polyvinyl ether compound; and

a sulfur-containing ethylenically unsaturated silane adduct, wherein the sulfur-containing ethylenically unsaturated silane adduct comprises the reaction product of reactants comprising (i) a mercaptosilane, and (ii) a polyene,

wherein the unreacted sealant composition comprises an essentially stoichiometric equivalent amount of thiol groups to ene groups.

2. The method of claim 1 , wherein the thiol-terminated polythioether comprises a structure having the formula:

—R 1 —[—S—(CH 2 ) 2 —O—[—R 2 —O] m —(CH 2 ) 2 —S—R 1 —] n —;

wherein

(1) each R 1 independently denotes a C 2-10 linear alkylene group, a C 2-6 branched alkylene group, a C 6-8 cycloalkylene group, a C 6-10 alkylcycloalkylene group, —[(—CH 2 —) p —X—] q —(—CH 2 —) r — or —[(—CH 2 —) p —X—] q —(—CH 2 —) r —in which at least one —CH 2 — unit is substituted with a methyl group, wherein:

(i) each X is independently selected from O, S, and —NR 6 —, wherein R 6 is hydrogen or methyl;

(ii) p is an integer having a value ranging from 2 to 6;

(iii) q is an integer having a value ranging from 0 to 5; and (iv) r is an integer having a value ranging from 2 to 10;

(2) each R 2 independently denotes a C 2-10 linear alkylene group, a C 2-6 branched alkylene group, a C 6-8 cycloalkylene group, a C 6-10 alkylcycloalkylene group, or —[(—CH 2 —) p —X—] q —(—CH 2 —) r —, wherein:

(i) each X is independently selected from O, S, and —NR 6 —, wherein R 6 is hydrogen or methyl;

(ii) p is an integer having a value ranging from 2 to 6;

(iii) q is an integer having a value ranging from 0 to 5; and

(iv) r is an integer having a value ranging from 2 to 10;

(3) m is a rational number from 0 to 10; and

(4) n is an integer having a value ranging from 1 to 60.

3. The method of claim 2 , wherein the thiol-terminated polythioether has the formula:

HS—R 1 —[—S—(CH 2 ) 2 —O—[—R 2 —O—] m —(CH 2 ) 2 —S—R 1 —] n —SH.

4. The method of claim 2 , wherein the thiol-terminated polythioether has the formula:

B-(A-[R 3 ] y —SH) z

wherein:

(1) A denotes a structure having the formula:

—R 1 —[—S—(CH 2 ) 2 —O—[—R 2 —O—] m —(CH 2 ) 2 —S—R 1 —] n —;

(2) y is 0 or 1;

(3) R 3 denotes a single bond when y=0 and —S—(CH 2 ) 2 —[—O—R 2 —] m —O— when y=1;

(4) z is an integer from 3 to 6; and

(5) B denotes a z-valent residue of a polyfunctionalizing agent.

5. The method of claim 1 , wherein the polyvinyl ether comprises the structure of Formula (IV):

CH 2 ═CH—O—((—R 5 —O—) m —CH═CH 2   (IV)

wherein R 5 is a C 2-6 linear alkylene group, a C 2-6 branched alkylene group, a C 6-8 cycloalkylene group, a C 6-10 alkylcycloalkylene group, or —[(—CH 2 —) p —O—] q —(—CH 2 —) r —, where p is an integer having a value ranging from 2 to 6, q is an integer having a value ranging from 1 to 5, and r is an integer having a value ranging from 2 to 10.

6. The method of claim 1 , wherein the polyvinyl ether comprises a divinyl ether.

7. The method of claim 1 , wherein the polyene (b) comprises a polyallyl compound.

8. The method of claim 7 , wherein the polyallyl compound comprises a triallyl compound.

9. The method of claim 8 , wherein the triallyl compound comprises a cyanurate.

10. The method of claim 1 , wherein the unreacted sealant composition further comprises a photoinitiator and the actinic radiation comprises ultraviolet radiation.

11. The method of claim 1 , wherein:

(1) the mercaptosilane has the structure of formula (V)

HS—R—Si(R 1 ) m (OR′) 3-m   (V)

wherein,

(i) R is a divalent organic group;

(ii) R′ is hydrogen or an alkyl group;

(iii) R 1 is hydrogen or an alkyl group; and

(iv) m is an integer from 0 to 2; and

(2) the polyene (ii) comprises a triene.

12. An unreacted composition comprising:

(a) a thiol-terminated polythioether; and

(b) a polyene comprising a polyvinyl ether compound; and

(c) a sulfur-containing ethylenically unsaturated silane adduct, wherein the sulfur-containing ethylenically unsaturated silane adduct comprises the reaction product of reactants comprising (i) a mercaptosilane, and (ii) a polyene,

wherein the composition comprises an essentially stoichiometric equivalent amount of thiol groups to ene groups.

13. The composition of claim 12 , wherein the thiol-terminated polythioether comprises a structure having the formula:

—R 1 —[—S—(CH 2 ) 2 —O—[—R 2 —O—] m —(CH 2 ) 2 —S—R 1 —] n —;

wherein

(1) each R 1 independently denotes a C 2-10 linear alkylene group, a C 2-6 branched alkylene group, a C 6-8 cycloalkylene group, a C 6-10 alkylcycloalkylene group, —[(—CH 2 —) p —X—] q —(—CH 2 —) r — or —[(—CH 2 —) p —X—] q —(—CH 2 —) r — in which at least one —CH 2 — unit is substituted with a methyl group, wherein:

(i) each X is independently selected from O, S, and —NR 6 —, wherein R 6 is hydrogen or methyl;

(ii) p is an integer having a value ranging from 2 to 6;

(iii) q is an integer having a value ranging from 0 to 5; and (iv) r is an integer having a value ranging from 2 to 10;

(2) each R 2 independently denotes a C 2-10 linear alkylene group, a C 2-6 branched alkylene group, a C 6-8 cycloalkylene group, a C 6-10 alkylcycloalkylene group, or —[(—CH 2 —) p —X—] q —(—CH 2 —) r —, wherein:

(i) each X is independently selected from O, S, and —NR—, wherein R 6 is hydrogen or methyl;

(ii) p is an integer having a value ranging from 2 to 6;

(iii) q is an integer having a value ranging from 0 to 5; and

(iv) r is an integer having a value ranging from 2 to 10;

(3) m is a rational number from 0 to 10; and

(4) n is an integer having a value ranging from 1 to 60.

14. The composition of claim 12 , wherein the polyene (b) comprises a polyallyl compound.

15. The composition of claim 12 , wherein the polyvinyl ether comprises a divinyl ether.

16. The composition of claim 12 , wherein:

(1) the mercaptosilane has the structure of formula (V)

HS—R—Si(R 1 ) m (OR′) 3-m   (V)

wherein,

(i) R is a divalent organic group;

(ii) R′ is hydrogen or an alkyl group;

(iii) R 1 is hydrogen or an alkyl group; and

(iv) m is an integer from 0 to 2; and

(2) the polyene (ii) comprises a triene.

17. The composition of claim 12 , wherein the ethylenically unsaturated silane adduct comprises at least one thiol group and at least one silane group.

18. The composition of claim 12 , formulated as a sealant.

19. An unreacted composition comprising:

(a) a thiol-terminated polythioether;

(b) a polyene comprising a polyvinyl ether compound;

(c) a photoinitiator; and

(d) a sulfur-containing ethylenically unsaturated silane adduct, wherein the sulfur-containing ethylenically unsaturated silane adduct comprises the reaction product of reactants comprising (i) a mercaptosilane, and (ii) a polyene,

wherein the composition comprises an essentially stoichiometric equivalent amount of thiol groups to ene groups.

20. The composition of claim 19 , wherein the thiol-terminated polythioether comprises a structure having the formula:

—R 1 —[—S—(CH 2 ) 2 —O—[—R 2 —O—] m —(CH 2 ) 2 —S—R 1 —] n —;

wherein

(1) each R 1 independently denotes a C 2-10 linear alkylene group, a C 2-6 branched alkylene group, a C 6-8 cycloalkylene group, a C 6-10 alkylcycloalkylene group, —[(—CH 2 —) p —X—] q —(—CH 2 —) r — or —[(—CH 2 —) p —X—] q —(—CH 2 —) r — in which at least one —CH 2 -unit is substituted with a methyl group, wherein:

(i) each X is independently selected from O, S, and —NR 6 —, wherein R 6 is hydrogen or methyl;

(ii) p is an integer having a value ranging from 2 to 6;

(iii) q is an integer having a value ranging from 0 to 5; and (iv) r is an integer having a value ranging from 2 to 10;

(2) each R 2 independently denotes a C 2-10 linear alkylene group, a C 2-6 branched alkylene group, a C 6-8 cycloalkylene group, a C 6-10 alkylcycloalkylene group, or —[(—CH 2 —) p —X—] q —(—CH 2 —) r —, wherein:

(i) each X is independently selected from O, S, and —NR—, wherein R 6 is hydrogen or methyl;

(ii) p is an integer having a value ranging from 2 to 6;

(iii) q is an integer having a value ranging from 0 to 5; and

(iv) r is an integer having a value ranging from 2 to 10;

(3) m is a rational number from 0 to 10; and

(4) n is an integer having a value ranging from 1 to 60.

21. The composition of claim 19 , wherein the polyvinyl ether comprises a divinyl ether.

22. The composition of claim 19 , wherein:

(1) the mercaptosilane has the structure of formula (V)

HS—R—Si(R 1 ) m (OR′) 3-m   (V)

wherein,

(i) R is a divalent organic group;

(ii) R′ is hydrogen or an alkyl group;

(iii) R 1 is hydrogen or an alkyl group; and

(iv) m is an integer from 0 to 2; and

(2) the polyene (ii) comprises a triene.

23. The composition of claim 19 , wherein the ethylenically unsaturated silane adduct comprises at least one thiol group and at least one silane group.

24. The composition of claim 19 , formulated as a sealant.

25. The composition of claim 19 , wherein the polyene (b) comprises a polyallyl compound.