Functionalized isobutylene-isoprene copolymer composition

1. A composition comprising a copolymer of the formula:

wherein

a is at least 20, and at least one of b and c are at least one;

X is oxygen or nitrogen;

R 1 is a covalent bond or a divalent (hetero)hydrocarbyl group;

Sil is a polydialkylsiloxane, and

x is 1 or 2.

2. The composition of claim 1 wherein the weight percent of the Sil groups in the copolymer is greater than 0.1 to less than 70 wt. %.

3. The composition of claim 1 wherein X is oxygen and x is 1, or X is nitrogen and x is 1 or 2.

4. The composition of claim 1 wherein —X—R 1 — is of the formula: —O—CO—R 2 —, where R 2 is an alkylene.

5. The composition of claim 1 wherein R 1 is an alkylene.

6. The composition of claim 1 wherein R 1 is —R 13 —O—R 14 , where R 13 and R 14 are alkylene.

7. The composition of claim 1 , wherein Sil is of the formula:

wherein

R 3 is each independently an alkyl, or aryl group;

R 5 is each independently an alkyl, aryl, or —Si(R 3 ) 2 R 5 ;

R 6 is each independently an alkyl, aryl, or —Si(R 3 ) 2 R 5 ;

z is 0 to 200; preferably 1-75; and

y is at least 3.

8. The composition of claim 7 wherein Sil is of the formula:

wherein

each R 7 is independently an alkyl, and z is at least 3.

9. A method of preparing the composition of claim 1 where the copolymer is made by the steps of hydrosilation of an isobutylene/isoprene copolymer having a pendent unsaturated group by a hydrido polydiorganosiloxane.

10. The method of claim 9 wherein the isobutylene/isoprene copolymer having a pendent unsaturated groups is prepared by nucleophilic displacement of a halogenated isobutylene/isoprene copolymer by an unsaturated compound having a nucleophilic functional group.

11. The method of claim 10 wherein the unsaturated compound having a nucleophilic functional group is an unsaturated alcohol, amine or carboxylic acid.

12. The method of claim 10 wherein the nucleophilic ethylenically unsaturated compound is of the formula:

wherein

X 1 is —O—, —O 2 C—, —NR 10 —, where R 10 is H or C 1 -C 4 alkyl, or —R 8 —C(R 9 )═CR 9 2 ; R 8 is a multivalent saturated or unsaturated alkylene or arylene, and each R 9 is independently selected from H or C 1 -C 4 alkyl, and any two of the R 9 groups may be taken together to form a carbocyclic ring.

13. The method of claim 9 wherein the hydrido polydiorganosiloxane is of the formula:

wherein

R 3 is each independently an alkyl, or aryl group;

R 5 is each independently an alkyl, aryl, or —Si(R 3 ) 2 R 5 ;

R 6 is each independently an alkyl, aryl, or —Si(R 3 ) 2 R 5 ;

z is 0 to 20; preferably 1-75; and

y is at least 10, and at least one of said R 5 or R 6 groups is H.

14. A coating composition comprising the copolymer of claim 1 and a non-functional elastomer.

15. The coating composition of claim 14 comprising:

a) 0.1-50 wt. % of the copolymer, and

b) 50-99.9 wt. % of the non-functional elastomer.

16. The coating composition of claim 14 wherein the non-functional elastomer is selected from polyisobutylenes, polyisoprenes, polybutadiene, butyl rubber, halogenated butyl rubbers, dienes, styrene rubber copolymers, acrylonitriles, and copolymers or mixtures thereof.