Reinforcing layer of pneumatic tire has rubber skim coatings on both sides of rubber embedded parallel reinforcing elements

摘要

A pneumatic tire has a reinforcing layer with parallel reinforcing elements individually embedded in a vulcanized rubber mixture with specified physical properties. One side of the layer has a rubber skim of constant composition and properties and the other side has a rubber skim whose composition and properties varies relative to the meridian position of the tire. Independent claims are included for the following: (a) Manufacturing a reinforcing layer as above comprises extruding the rubber around the elements, and spacing out the coated elements before they pass between upper and intermediate calendar rolls. The rubber skim mixture is transferred from a lower calendar roll to the intermediate roll. A fourth roll applies a non-stick layer to one face of the layer before the band rolling it around a drum. (b) Manufacturing a tire by applying the above reinforcing layer to a roughly formed tire carcass. Preferred Features: The rubber around the elements and forming the constant property skim are of a first mixture that has a Mooney viscosity 60 - 90 UM when unvulcanized and an elastic modulus of 6 -12 MPa when vulcanized. The second rubber skim has four layers. Three of the layers have the same Mooney viscosity and elastic modulus as the first mixture. The fourth layer has a viscosity of 55- 75 UM and elastic modulus of 3.5 - 5.5 MPa.