Silicone-polyether copolymer, sealants comprising same, and related methods

1. A silicone-polyether copolymer having the formula X g [Z j Y o ] c ,

wherein each X is independently a silicone moiety having one of formulas (I) or (II):

each Y is an independently selected polyether moiety, and each Z is an independently selected siloxane moiety having the formula [R 1 h SiO( 4-h )/ 2 ] d ,

where each R 1 is an independently selected substituted or unsubstituted hydrocarbyl group having from 1 to 18 carbon atoms; each R 2 is an independently selected substituted or unsubstituted hydrocarbyl group having from 1 to 18 carbon atoms; each D 1 is an independently selected divalent hydrocarbon group having from 2 to 18 carbon atoms; each subscript a is independently 0 or 1; each subscript b is independently 0 or 1; subscript c is from 1 to 150; each subscript d is from 1 to 1000; each subscript e is independently 1 or 2; each subscript f is independently 0 or 1, with the provisos that within each X, when f is 1, b is 1, and when b is 1, f is 1; subscript g is >1; subscript h is independently selected from 0 to 2 in each moiety indicated by subscript d; each subscript j is independently >0 and <2; each subscript o is independently >0 and <2, with the proviso that j+o=2 in each moiety indicated by subscript c; subscript t is ≥0; and

subscript u is >0.

2. The silicone-polyether copolymer of claim 1 , wherein the silicone-polyether copolymer has the formula:

wherein each X, Y, R 1 , subscript c, and subscript d is defined above.

3. The silicone-polyether copolymer of claim 1 , wherein:

(i) each polyether moiety Y comprises a polyether group having the formula

—O—(C n H 2n O) w —,

wherein subscript n is independently selected from 2 to 4 in each moiety indicated by subscript w, and subscript w is from 1 to 1000;

(ii) each polyether moiety Y has a number average molecular weight of at least about 100;

(iii) at least one polyether moiety Y is a polyhydroxyl polyether; or

(vi) a combination of (i)-(iii).

4. The silicone-polyether copolymer of claim 1 , wherein each polyether moiety Y has the formula:

—CH 2 —CH(R 3 )-[D 2 ] m -O—[C 2 H 4 O] x [C 3 H 6 O] y [C 4 H 8 O] z -[D 2 ] m -CH(R 3 )—CH 2 —,

wherein each R 3 is independently a hydrocarbyl group having from 1 to 6 carbon atoms, an alkoxy group, a silyl group, or H; each D 2 is an independently selected divalent group having from 1 to 6 carbon atoms, subscript m is 0 or 1, subscript x is from 0 to 999, subscript y is from 1 to 1000, and subscript z is from 0 to 999, and wherein units indicated by subscripts x, y and z may be in randomized or block form in the polyether moiety Y.

5. The silicone-polyether copolymer of claim 1 , wherein:

(i) each R 1 is methyl;

(ii) each R 2 is propyl;

(iii) each subscript a is 0;

(iv) each D 1 is C 2 H 4 ; or

(v) any combination of (i) to (iv).

6. A method of preparing a silicone-polyether copolymer, said method comprising:

reacting a polyether compound having on average more than one terminal unsaturated group, a chain extending organosilicon compound, and an endcapping organosilicon compound in the presence of a hydrosilylation catalyst to give the silicone-polyether copolymer;

wherein the silicone-polyether copolymer is according to claim 1 .

7. The method of claim 6 , wherein

the polyether compound has the formula:

Y 1 [R 4 ] i ,

wherein each R 4 is an independently selected unsaturated group having from 2 to 14 carbon atoms; subscript i is >1; and

Y 1 is an independently selected polyether moiety comprising a polyether group having the formula

—O—(C n H 2n O) w —,

wherein subscript n is independently selected from 2 to 4 in each moiety indicated by subscript w, and subscript w is from 1 to 1000.

8. The method of claim 7 , wherein in the polyether compound:

(i) the polyether moiety Y 1 has the formula:

—O—[C 2 H 4 O] x [C 3 H 6 O] y [C 4 H 8 O] z —,

wherein each subscript x is independently from 0 to 999, each subscript y is independently from 1 to 1000, and each subscript z is independently from 0 to 999, and

wherein units indicated by subscripts x, y and z may be in randomized or block form in the polyether moiety Y 1 ;

(ii) each R 4 has the formula:

CH 2 ═C(R 3 )-[D 2 ] m -,

wherein each R 3 is independently a hydrocarbyl group having from 1 to 6 carbon atoms, an alkoxy group, a silyl group, or H; each D 2 is an independently selected divalent group having from 1 to 6 carbon atoms, and subscript m is 0 or 1; or

(iii) both (i) and (ii).

9. The method of claim 8 , wherein in each R 4 of formula

CH 2 ═C(R 3 )-[D 2 ] m -:

(i) each R 3 is methyl;

(ii) each subscript m is 1 and each D 2 is CH 2 ; or

(iii) both (i) and (ii).

10. The method of claim 6 , wherein the chain extending organosilicon compound comprises:

(i) a linear silicon hydride functional organosilicon compound;

(ii) a branched silicon hydride functional organosilicon compound; or

(iii) both (i) and (ii).

11. The method of claim 10 , wherein the chain extending organosilicon compound comprises the linear silicon hydride functional organosilicon compound, and wherein the linear silicon hydride functional organosilicon compound has the formula:

wherein each R 1 is an independently selected substituted or unsubstituted hydrocarbyl group having from 1 to 18 carbon atoms; and each subscript d′ is from 1 to 999.

12. The method of claim 6 , wherein the endcapping organosilicon compound has formula (III) or (IV):

wherein each R 1 , R 2 , D 1 , subscript a, subscript b, subscript e, subscript f, subscript t, and subscript u are as defined above.

13. The method of claim 6 , comprising:

(i) reacting the polyether compound and the chain extending organosilicon compound in the presence of the hydrosilylation catalyst to give a chain-extended silicone-polyether compound, and reacting the chain-extended silicone-polyether compound and the endcapping organosilicon compound in the presence of a hydrosilylation catalyst to give the silicone-polyether copolymer;

(ii) reacting the polyether compound and the endcapping organosilicon compound in the presence of the hydrosilylation catalyst to give an endcapped silicone-polyether compound, and reacting the endcapped silicone-polyether compound and the chain extending organosilicon compound in the presence of a hydrosilylation catalyst to give the silicone-polyether copolymer; or

(iii) both (i) and (ii).

14. The method of claim 13 , comprising (i) reacting the polyether compound and the chain extending organosilicon compound in the presence of the hydrosilylation catalyst to give the chain-extended silicone-polyether compound, wherein the chain-extended silicone-polyether compound has the formula:

where each R 4 is an independently selected unsaturated group having from 2 to 14 carbon atoms;

subscript c is from 1 to 150; each subscript d is from 1 to 1000; and each Y 1 is an independently selected polyether moiety comprising a polyether group having the formula —O—(C n H 2n O) w —, wherein subscript n is independently selected from 2 to 4 in each moiety indicated by subscript w, and subscript w is from 1 to 1000.

15. The method of claim 14 , wherein in the chain-extended silicone-polyether compound:

(i) each polyether moiety Y 1 has the formula:

—O—[C 2 H 4 O] x [C 3 H 6 O] y [C 4 H 8 O] z —,

wherein each subscript x is independently from 0 to 999, each subscript y is independently from 1 to 1000, and each subscript z is independently from 0 to 999, and wherein units indicated by subscripts x, y and z may be in randomized or block form in the polyether moiety Y 1 ;

(ii) each R 4 has the formula:

CH 2 ═C(R 3 )-[D 2 ] m -,

wherein each R 3 is independently a hydrocarbyl group having from 1 to 6 carbon atoms, an alkoxy group, a silyl group, or H; each D 2 is an independently selected divalent group having from 1 to 6 carbon atoms, and subscript m is 0 or 1; or

(iii) both (i) and (ii).

16. A silicone-polyether copolymer prepared in accordance with the method of claim 6 .

17. A sealant, comprising:

a silicone-polyether copolymer; and

a condensation reaction catalyst;

wherein the silicone-polyether copolymer is according to claim 1 .

18. A cured product of the sealant of claim 17 .

19. A composite article comprising a substrate and the cured product of claim 18 disposed on the substrate.