Pneumatic Object Provided with a Gas-Tight Layer Comprising a Thermoplastic Elastomer and Expanded Thermoplastic Microspheres

摘要

An inflatable article provided with an elastomer layer impermeable to the inflation gas, such as air, said layer comprising at least, as major elastomer, a thermoplastic polystirene/polyisobutylene block copolymer, such as an SIBS (stirene/isobutylene/stirene) copolymer, and expanded thermoplastic microspheres with a preferential content between 1 and 30 phr. Preferably, this copolymer comprises between 5% and 50% stirene by weight, its number-average molecular weight is between 30 000 and 500 000 g/mol and its Tg is below −20° C. Optionally, the gastight elastomer layer also contains, as plasticizer, an extender oil, especially a polybutene oil, with a preferential content between 5 and 100 phr. This gastight layer not only has excellent impermeability properties, but also a density and a hysteresis that are both reduced compared with layers based on butyl rubber. The inflatable article can be a pneumatic tire for a motor vehicle.