Abstract: Aspects of the present invention relate to methods for characterizing a multi-layered tire tread. In one example, a method comprises providing a first rubber composition having a first refractive index and providing a second rubber composition having a second refractive index. The method further comprises determining a difference between the first refractive index and the second refractive index and comparing the difference to a threshold refractive index. In addition, the method comprises adding a refractive index modifier to the first rubber composition and/or second rubber composition in case the comparison provides that the difference is lower than the threshold refractive index, so that the difference is greater than, or equal to, the threshold refractive index.

Abstract: Aspects of the present invention relate to methods for characterizing a multi-layered tire tread. In one example, a method comprises providing a first rubber composition having a first refractive index and providing a second rubber composition having a second refractive index. The method further comprises determining a difference between the first refractive index and the second refractive index and comparing the difference to a threshold refractive index. In addition, the method comprises adding a refractive index modifier to the first rubber composition and/or second rubber composition in case the comparison provides that the difference is lower than the threshold refractive index, so that the difference is greater than, or equal to, the threshold refractive index.

Abstract: Aspects of the present invention relate to a tire tread production line and a method for manufacturing a tire tread. The production line comprises a coextruder, a THz sensor and a controller operatively connected to the coextruder and to the THz sensor. The THz sensor is configured to irradiate the multi-layer tire tread extrudate with THz electromagnetic radiation, and receive a response of the multi-layer tire tread extrudate to the THz electromagnetic radiation. The controller is configured to operate the coextruder based on the response of the multi-layer tire tread extrudate to the THz electromagnetic radiation.

Abstract: Aspects of the present invention relate to methods for characterizing a multi-layered tire tread. In one example, a method comprises providing a first rubber composition having a first refractive index and providing a second rubber composition having a second refractive index. The method further comprises determining a difference between the first refractive index and the second refractive index and comparing the difference to a threshold refractive index. In addition, the method comprises adding a refractive index modifier to the first rubber composition and/or second rubber composition in case the comparison provides that the difference is lower than the threshold refractive index, so that the difference is greater than, or equal to, the threshold refractive index.