Pneumatic article provided with a self-sealing composition
View Patent ↗An inflatable article such as a pneumatic tire provided with a puncture-resistant layer comprising, by way of a self-sealing composition, an elastomer composition comprising at least, as predominant elastomer, a thermoplastic styrene (TPS) elastomer, more than 200 phr of an extender oil and more than 20 phr of a hydrocarbon resin, the glass transition temperature of which is greater than 0° C. The puncture-resistant layer is advantageously combined with an airtight layer, for example based on butyl rubber, so as to form, in the pneumatic article, an airtight puncture-resistant laminate.
1. An inflatable article provided with a puncture-resistant layer comprising, by way of a self-sealing composition, an elastomer composition comprising at least, as predominant elastomer, a thermoplastic styrene (TPS) elastomer, more than 200 phr of an extender oil and more than 20 phr of a hydrocarbon resin, the hydrocarbon resin having a glass transition temperature (T g ) greater than 0° C.
2. The article according to claim 1 , wherein the TPS elastomer is chosen from the group consisting of styrene/butadiene/styrene, styrene/isoprene/styrene, styrene/butadiene/isoprene/styrene, styrene/isobutylene/styrene, styrene/ethylene-butylene/styrene, styrene/ethylene-propylene/styrene and styrene/ethylene-ethylene-propylene/styrene block copolymers and blends of these copolymers.
3. The article according to claim 2 , wherein the TPS elastomer is selected from the group consisting of styrene/ethylene-butylene/styrene copolymers, styrene/ethylene-propylene/styrene copolymers and blends of these copolymers.
4. The article according to claim 1 , wherein the TPS elastomer comprises between 5 and 50% styrene by weight.
5. The article according to claim 1 , wherein a glass transition temperature (T g ) of the TPS elastomer is below −20° C.
6. The article according to claim 1 , wherein the number-average molecular weight (M n ) of the TPS elastomer is between 50 000 and 500 000 g/mol.
7. The article according to claim 1 , wherein the extender oil is selected from the group consisting of polyolefin oils, paraffinic oils, naphthenic oils, aromatic oils, mineral oils and mixtures of these oils.
8. The article according to claim 7 , wherein the extender oil is selected from the group consisting of polybutenes, paraffinic oils and mixtures of these oils.
9. The article according to claim 8 , wherein the extender oil is a polyisobutylene oil.
10. The article according to claim 1 , wherein the number-average molecular weight (M n ) of the extender oil is between 200 and 30 000 g/mol.
11. The article according to claim 1 , wherein the extender oil content is between 200 and 700 phr.
12. The article according to claim 1 , wherein the hydrocarbon resin content is between 20 and 200 phr.
13. The article according to claim 1 , wherein the hydrocarbon resin has a T g greater than +20° C.
14. The article according to claim 1 , wherein the number-average molecular weight (M n ) of the hydrocarbon resin is between 400 and 2 000 g/mol.
15. The article according to claim 1 , wherein the hydrocarbon resin is selected from the group consisting of cyclopentadiene or dicyclopentadiene homopolymer or copolymer resins, terpene homopolymer or copolymer resins, C 5 -cut homopolymer or copolymer resins, and blends of these resins.
16. The article according to claim 15 , wherein the hydrocarbon resin is selected from the group consisting of cyclopentadiene or dicyclopentadiene homopolymer resins, cyclopentadiene or dicyclopentadiene/styrene copolymer resins, polylimonene resins, limonene/styrene copolymer resins, limonene/cyclopentadiene or dicyclopentadiene copolymer resins, C 5 -cut/styrene copolymer resins, C 5 -cut/C 9 -cut copolymer resins, and blends of these resins.
17. The article according to claim 1 , wherein the self-sealing composition is used in the form of a puncture-resistant layer, the thickness of which is greater than 0.3 mm.
18. The article according to claim 17 , wherein the puncture-resistant layer has a thickness of between 0.5 mm and 10 mm.
19. The article according claim 1 , wherein the puncture-resistant layer is deposited on the inner wall of the inflatable article.
20. The article according to claim 1 , wherein the inflatable article is a rubber article.
21. The article according to claim 20 , wherein the inflatable article is a pneumatic tire.
22. The article according to claim 1 , wherein the puncture-resistant layer is combined with an airtight layer, thus forming an airtight self-sealing laminate.
23. The article according to claim 22 , wherein the airtight layer is based on butyl rubber.