Tyre inner liner

Abstract

The present invention concerns a tyre of which the inner liner comprises a rubber composition made at least principally from a highly unsaturated diene elastomer, a reinforcing organic filler, graphite, chalk, and a hydrocarbon plasticising resin of which the vitreous transition temperature, Tg, is higher than 20°C and the softening temperature is lower than 170°C. Using such a composition in the tyre inner liner, including graphite and a non-reinforcing chalk filler, makes it possible to considerably improve the sealing properties relative to a control composition that comprises only graphite and that already offers an excellent performance in this respect, but also relative to a control composition conventionally used in tyre inner liners, while keeping the properties of rigidity and processability as high-level as conventional control compositions.

Description

technical field [0001] This invention relates to rubber compositions useful in the manufacture of airtight tire inner layers, commonly referred to as tire "liners". Background technique [0002] Tubeless tires have an inner surface with low air permeability to prevent the tire from deflating and to protect sensitive inner areas of the tire from the ingress of oxygen and water, such as the carcass plies containing oxidation-sensitive metal cords, such Protection improves the durability of the tire. Currently, this protection of the inner surface of the tire is achieved by an innerliner composed of an elastomeric composition based on butyl rubber. However, the airtight properties of butyl rubber are linked to a non-negligible minimum thickness (of the order of millimeters) and thus to a certain weight, which does not make it possible to effectively meet these new demands. [0003] Therefore, there is a need to add reinforcing fillers such as carbon black to elastomeric inner...

AI Technical Summary

Problems solved by technology

However, large amounts of these reinforcing fillers impair the composition in the uncured state: difficulty in processing uncured compositions, commonly referred to as "processing" difficulties, and in the cured state: reduction in mechanical properties, especially some properties of flexural strength

The introduction of oil-based plasticizers made it possible to overcome these processing and mechanical performance aspects, but the damage to airtightness was very large

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