Modified isobutylene-isoprene rubber, preparation method therefor, and cured product

1. A modified isobutylene-isoprene rubber (IIR) comprising a structural unit of the following Chemical Formula 14:

in Chemical Formula 14, Z is an alkyl group comprising at least two substituted or unsubstituted aminoethyl ester group.

2. The modified isobutylene-isoprene rubber of claim 1 , wherein in Chemical Formula 14, Z is a functional group represented by the following Chemical Formula 15, a functional group represented by the following Chemical Formula 16, or a functional group represented by the following Chemical Formula 17:

in Chemical Formula 15 to Chemical Formula 17, R 1 to R 17 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms; or hydrogen.

3. The modified isobutylene-isoprene rubber of claim 1 , wherein the modified isobutylene-isoprene rubber comprises 0.5 mol % to 10.0 mol % of the structural unit of Chemical Formula 14 in the entire structural units.

4. The modified isobutylene-isoprene rubber of claim 1 , wherein the modified isobutylene-isoprene rubber does not comprise a sulfur atom and a halogen atom.

5. The modified isobutylene-isoprene rubber of claim 1 , wherein the modified isobutylene-isoprene rubber comprising the structural unit of Chemical Formula 14 is a reaction product of an intermediate modified isobutylene-isoprene rubber comprising a structural unit of the following Chemical Formula 1 and an aziridine-based compound represented by the following Chemical Formula 18:

in Chemical Formula 1, X is an alkyl group comprising at least two carboxyl groups,

in Chemical Formula 18, R 13 to R 17 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms; or hydrogen.

6. The modified isobutylene-isoprene rubber of claim 5 , wherein in Chemical Formula 1, X is a functional group represented by the following Chemical Formula 2, a functional group represented by the following Chemical Formula 3, or a functional group represented by the following Chemical Formula 4:

in Chemical Formula 2 to Chemical Formula 4, R 1 to R 12 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms; or hydrogen.

7. The modified isobutylene-isoprene rubber of claim 5 , wherein the intermediate modified isobutylene-isoprene rubber comprises 0.5 mol % to 10.0 mol % of the structural unit of Chemical Formula 1 in the entire structural units.

8. The modified isobutylene-isoprene rubber of claim 1 , wherein the modified isobutylene-isoprene rubber comprises 90.0 mol % to 95.5 mol % of a structural unit of the following Chemical Formula 5 in the entire structural units:

9. A cured product formed by thermally curing or photo-curing a composition comprising the modified isobutylene-isoprene rubber of claim 1 .

10. The cured product of claim 9 , wherein the cured product does not comprise a sulfur atom and a halogen atom.

11. The cured product of claim 9 , wherein the cured product has a gel fraction of 10% or more.

12. A method for preparing a modified isobutylene-isoprene rubber (IIR), the method comprising:

reacting a primary modified isobutylene-isoprene rubber comprising a structural unit of the following Chemical Formula 1 with an aziridine-based compound represented by the following Chemical Formula 18:

in Chemical Formula 1, X is an alkyl group comprising at least two carboxyl groups,

in Chemical Formula 18, R 13 to R 17 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms; or hydrogen.

13. The method of claim 12 , wherein as a reaction product of the primary modified isobutylene-isoprene rubber and the aziridine-based compound represented by Chemical Formula 18, a secondary modified isobutylene-isoprene rubber comprising a structural unit of the following Chemical Formula 14 is prepared:

in Chemical Formula 14, Z is an alkyl group comprising at least two substituted or unsubstituted aminoethyl ester group.

14. The method of claim 13 , wherein in Chemical Formula 14, Z is a functional group represented by the following Chemical Formula 15, a functional group represented by the following Chemical Formula 16, or a functional group represented by the following Chemical Formula 17:

in Chemical Formula 15 to Chemical Formula 17, R 1 to R 17 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms; or hydrogen.

15. The method of claim 13 , wherein 0.5 part by weight to 20 parts by weight of the aziridine-based compound is reacted based on 100 parts by weight of the primary modified isobutylene-isoprene rubber.

16. The method of claim 12 , further comprising:

preparing a raw material composition by mixing an isobutylene-isoprene rubber comprising a structural unit of the following Chemical Formula 5 and a structural unit of the following Chemical Formula 13 with a solvent;

forming an intermediate product by adding a cyclic acid anhydride comprising a carbon-carbon double bond and a radical initiator to the raw material composition to react the isobutylene-isoprene rubber with the cyclic acid anhydride comprising the carbon-carbon double bond; and

forming the primary modified isobutylene-isoprene rubber from the intermediate product by adding an aqueous acidic solution or an aqueous basic solution to a raw material composition comprising the intermediate product.

17. The method of claim 16 , wherein the acid anhydride comprises at least one selected from the group consisting of a compound represented by the following Chemical Formula 6, a compound represented by the following Chemical Formula 7, a compound represented by the following Chemical Formula 8, and a combination thereof:

in Chemical Formulae 6 to 8, R 1 to R 12 are each independently hydrogen; or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms.

18. The method of claim 16 , wherein the intermediate product is formed so as to comprise a structural unit of the following Chemical Formula 9:

in Chemical Formula 9, Y is a derivative derived from the cyclic acid anhydride comprising the carbon-carbon double bond.

19. The method of claim 18 , wherein in Chemical Formula 9, Y is a functional group represented by the following Chemical Formula 10, a functional group represented by the following Chemical Formula 11, or a functional group represented by the following Chemical Formula 12:

in Chemical Formulae 10 to 12, R 1 to R 12 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms; or hydrogen.

20. The method of claim 16 , wherein 0.5 part by weight to 10 parts by weight of the acid anhydride is added to the primary modified isobutylene-isoprene rubber based on 100 parts by weight of the primary modified isobutylene-isoprene rubber.