Pneumatic tire having built-in colored sealant layer and preparation thereof

Abstract

This invention relates to a pneumatic tire having a built-in non-black colored sealant layer and its preparation. The sealant layer is derived from a sealant precursor layer comprised of a butyl rubber, organoperoxide, particulate, synthetic amorphous silica and plant-derived organic agricultural seed flour, together with a non-black colored colorant. The butyl rubber-based sealant precursor layer is build into the tire to form a tire assembly and the butyl rubber component of the sealant precursor layer is depolymerized during a subsequent curing of the tire at an elevated temperature in a suitable mold to form the tire having the resultant built-in sealant. The particulate plant derived organic agricultural seed flour is a renewable raw material in a sense that it can be replenished in nature and therefore not as a significant depletion of non-renewable natural resource. The agricultural plant seed flour is comprised of at least a portion of a ground plant seed (e.g. whole or partial seed portion including for example its nucleus and/or shell) of an agricultural seed producing plant such as, for example, wheat, rye, rice, barley, oat, mullet, soybean and/or corn. The sealant layer may also contain one or more of a liquid polyisoprene and short organic fibers. Preferably, the amorphous silica is a precipitated silica, namely aggregates of primary silica particles.