Stiff tyre sub-tread reinforcement plies - enclosed in a relatively flexible envelope to obtain low rolling resistance without ply border delamination

摘要

Subtread reinforcement plies are assembled as two or more flat layers of material (I) having a modulus of elasticity >3500 kg/mm2 (260g/denier) enclosed in an open mesh fabric of elastic material (II) having a modulus of elasticity of 2000 kg/mm2. Specifically (I) comprises steel and/or aromatic polyamide or aramide, e.g. "Kevlar" (RTM), and (II) comprises an aliphatic polyamide or polyester or cellulose acetate. Used for circumferential reinforcement of radial ply tyres, the structure combines a low-rolling resistance with low susceptibility to delamination along the edges of the stiff plies.