Process for preparing amino-mercapto functional organopolysiloxanes

1. A process for the preparation of an amino-mercapto functional polysiloxane comprising reacting:

(A) a dialkoxydialkylsilane,

(B) an amino functional alkoxy silane, and

(C) a mercapto functional alkoxy silane, and optionally

(D) an endblocker selected from an alcohol, monoalkoxysilane, or disilazane via a condensation reaction.

2. The process of claim 1 wherein the amino-mercapto functional organopolysiloxane comprises siloxy units having the average formula;

[R 2 SiO] a [RR N SiO] b [RR S SiO] c

where; a is 1-4000, b is 1-1000, c is 1-1000,

R is independently a monovalent organic group,

R N is a monovalent amino functional organic group, and

R S is a monovalent mercapto functional organic group.

3. The process of claim 2 wherein the amino-mercapto functional organopolysiloxane has the average formula;

where a is 1-4000, b is 1-1000, c is 1-1000,

R′ is H, an alkyl group having 1 to 40 carbon atoms, or Me 3 Si.

4. The process of claim 3 where a is 1-200, b is 1-50, c is 1-50, and R′ is an alkyl group having 1 to 20 carbon atoms.

5. The process of claim 1 where the molar amounts of components (A), (B), and (C) are selected such to provide a molar percentage of each to be;

(A) 1 to 99.5,

(B) 0.5 to 60,

(C) 0.5 to 60,

where (A)+(B)+(C) sums to 100%.

6. The process of claim 1 where the dialkoxydialkylsilane is dimethoxydimethylsilane.

7. The process of claim 1 wherein the amino functional alkoxy silane has the formula

R 3 h R N i Si(OR 4 ) [4−(h+i)]

where h is 0, 1 or 2,

i is 1 or 2, with the proviso that (h+i)≦3,

R N is an amino functional organic group,

R 3 is a hydrocarbon group containing 1 to 30 carbon atoms,

R 4 is an alkyl group containing 1-20 carbon atoms.

8. The process of claim 1 wherein the amino functional alkoxy silane is selected from;

(CH 3 O) 2 (CH 3 )Si(CH 2 ) 3 NH 2 ,

(CH 3 O) 2 (CH 3 )Si(CH 2 ) 4 NH 2 ,

(CH 3 O) 2 (CH 3 )Si(CH 2 ) 3 NH(CH 2 ) 2 NH 2 ,

(CH 3 O) 2 (CH 3 )SiCH 2 CH(CH 3 )CH 2 NH(CH 2 ) 2 NH 2 ,

(CH 3 O) 2 (CH 3 )SiCH 2 CH(CH 3 )CH 2 NH(CH 2 ) 3 NH 2 ,

(CH 3 O) 2 (CH 3 )Si(CH 2 ) 3 NH(CH 2 ) 2 NH(CH 2 ) 2 NH 2 ,

(CH 3 O) 2 (CH 3 )Si(CH 2 ) 3 NH(CH 2 ) 4 NH 2 , or

(CH 3 O) 2 (CH 3 )Si(CH 2 ) 3 O(CH 2 ) 2 NH 2 .

9. The process of claim 1 wherein the mercapto functional, alkoxy silane has the formula;

R 3 h R S i Si(OR 4 ) [4−(h+i)]

where h is 0, 1 or 2, i is 1 or 2, with the proviso that (h+i)≦3,

R S is a mercapto functional organic group,

R 3 is a hydrocarbon group containing 1 to 30 carbon atoms,

R 4 is an alkyl group containing 1-20 carbon atoms.

10. The process of claim 1 wherein the mercapto functional silane is selected from

(C 2 H 5 O) 2 (CH 3 )SiCH 2 CH 2 CH 2 SH,

(C 2 H 5 O) 2 (CH 3 )SiCH 2 CH(CH 3 )SH,

(C 2 H 5 O) 2 (CH 3 )SiCH 2 CH 2 CH 2 CH 2 SH,

(C 2 H 5 O) 2 (CH 3 )SiCH 2 CH 2 CH 2 CH 2 CH 2 SH,

(C 2 H 5 O) 2 (CH 3 )SiCH 2 CH 2 CH 2 CH 2 CH 2 CH 2 SH,

(C 2 H 5 O) 2 (CH 3 )SiCH 2 CH 2 SCH 3

(C 2 H 5 O) 3 SiCH 2 CH 2 CH 2 SH,

(C 2 H 5 O) 3 SiCH 2 CH(CH 3 )SH,

(C 2 H 5 O) 3 SiCH 2 CH 2 CH 2 CH 2 SH,

(C 2 H 5 O) 3 SiCH 2 CH 2 CH 2 CH 2 CH 2 SH,

(C 2 H 5 O) 3 SiCH 2 CH 2 CH 2 CH 2 CH 2 CH 2 SH, or

(C 2 H 5 O) 3 SiCH 2 CH 2 SCH 3 .

11. A process for the preparation of an amino-mercapto functional polysiloxane comprising

I) heating a mixture of (A) a dialkoxydialkylsilane and water, then

II) adding (B) an amino functional alkoxy silane, and (C) a mercapto functional alkoxy silane, and optionally (D) an endblocker selected from an alcohol, monoalkoxysilane, or disilazane, and III) reacting the resulting mixture via a condensation reaction.

12. The process of claim 11 wherein step I further comprises the addition of ethylenediaminetetraacetic acid.