Low ratio RTV compositions and methods for making same

1. A two-part moisture-curing composition comprising:

a) first part comprising water and a hydroxy-terminated polydiorganosiloxane; and

b) a second part comprising:

i. a reactive silicone having the formula:

wherein

a is 0, 1, or 2;

m is from about 1 to about 2,400;

R 1 in each occurrence may be the same or different and is a C 1 to C 10 hydrocarbon radical;

R 2 in each occurrence may be the same or different and is a C 1 to C 10 hydrocarbon radical; and

R 3 is a alkenoxy group; and

ii. at least one end-capping silane having the formula

R 4 a —Si—R 5 3-a R 4 a —Si—R 5 4-a

wherein

a is 0, 1, or 2;

R 4 is a C 1 to C 10 hydrocarbon radical;

R 5 is a alkenoxy group having the structure:

wherein R 6 in each occurrence can be the same or different and is selected from the group consisting of H and C 1 to C 3 alkyl; and

iii. at least one end-capping catalyst; and

iv. at least one moisture-cure catalyst.

2. The composition of claim 1 , wherein the second part further comprises a hydroxy-terminated polydiorganosiloxane.

3. The composition of claim 1 , wherein the second part further comprises an alkoxysilane.

4. The composition of claim 1 , wherein the volume mix ratio of the first part to the second part is from about 4:1 to about 1:1.

5. The composition of claim 4 , wherein the volume mix ratio is 1:1.

6. The composition of claim 1 , wherein the water of the first part is present in a filler.

7. The composition of claim 1 , wherein

R 1 and R 2 may be the same or different, and are selected consisting of C 1 to C 4 alkyl, vinyl, and phenyl; and

R 3 is

8. The composition of claim 1 , wherein

a is 1

R 1 is methyl;

R 2 is vinyl;

R 3 is

the end-capping silane of the second part is vinyltriisopropenoxysilane;

the end capping-catalyst is an amine catalyst; and

the moisture-cure catalyst is a tin-based catalyst.

9. The composition of claim 1 , further comprising a filler.

10. The composition of claim 1 , further comprising a plasticizer.

11. The composition of claim 1 , further comprising adhesion promoters.

12. A method for using the composition of claim 1 to join or seal two substrates comprising the steps of:

a) mixing the first part and the second part;

b) applying the composition to at least one of two substrate surfaces;

c) mating the two substrate surfaces in an abutting relationship to form an assembly; and

d) maintaining the abutting relationship for a time sufficient to allow the composition to cure.

13. A method of preparing a silicone polymer comprising admixing:

a) a first part comprising water and a hydroxy-terminated polydiorganosiloxane; with

b) a second part comprising:

i. a reactive silicone having the formula:

wherein

a is 0, 1, or 2;

m is 1 to about 2,400;

R 1 in each occurrence may be the same or different and is a C 1 to C 10 hydrocarbon radical;

R 2 in each occurrence may be the same or different and is a C 1 to C 10 hydrocarbon radical; and

R 3 is a alkenoxy group; and

ii. at least one end-capping silane having the formula

R 4 a —Si—R 5 3-a R 4 a —Si—R 5 4-a

wherein

a is 0, 1, or 2;

R 4 is a C 1 to C 10 hydrocarbon radical;

R 5 is a alkenoxy group having the structure:

wherein R 6 in each occurrence can be the same or different and is selected from the group consisting of H and C 1 to C 3 alkyl; and

iii. at least one end-capping catalyst; and

iv. at least one moisture-cure catalyst;

and permitting the first part and second part to react.

14. The method of claim 13 , wherein the mix ratio of the first part to the second part is from about 4:1 to about 1:1.

15. A silicone composition comprising the reaction product of:

a) a first part comprising water and a hydroxy-terminated polydiorganosiloxane; and

b) a second part comprising:

i. a reactive silicone having the formula:

wherein

a is 0, 1, or 2;

m is 1 to about 2,400;

R 1 in each occurrence may be the same or different and is a C 1 to C 10 hydrocarbon radical;

R 2 in each occurrence may be the same or different and is a C 1 to C 10 hydrocarbon radical;

R 3 is a alkenoxy group; and

ii. at least one end-capping silane having the formula:

R 4 a —Si—R 5 4-a

wherein

a is 0, 1, or 2;

R 4 is a C 1 to C 10 hydrocarbon radical; and

R 5 is an alkenoxy group having the structure:

wherein R 6 in each occurrence can be the same or different and is selected from the group consisting of H and C 1 to C 3 alkyl;

iii. at least one end-capping catalyst; and

iv. at least one moisture-cure catalyst.

16. The composition of claim 15 , wherein the volume mix ratio of the first part to the second part is from about 4:1 to about 1:1.

17. The composition of claim 15 , wherein the second part further comprises a hydroxy-terminated polydiorganosiloxane.

18. The composition of claim 15 , wherein the second part further comprises an alkoxysilane.