A process for the manufacture of a tread band, wherein the blocks thereof comprise different portions having differing hysteresis losses. The process comprises a step for the extrusion of a preliminary tread band consisting of a first rubber compound and an injection step, wherein the preliminary tread band, once extruded, is subjected to the action of at least one injector arranged such as to penetrate into the layer of the preliminary tread band and to release a second rubber compound, which is distributed within the layer consisting of said first compound, maintaining exposed a surface that is suitable for defining a portion of the ground-contacting surface of the resulting tread band.

This disclosure provides a rubber composition that can realize excellent low heat generating properties without deteriorating other performance. The rubber composition contains a rubber component and a filler, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1).

##STR00001##

A pneumatic tire of the present disclosure includes, on a tread surface, circumferential main grooves extending in a tire circumferential direction and land portions defined between circumferential main grooves adjacent in a tire width direction among the circumferential main grooves or by the circumferential main grooves and tread edges. The land portions include widthwise grooves extending in the tire width direction and are divided into blocks by the widthwise grooves. At least one widthwise sipe extending in the tire width direction is included within the blocks. Hard rubber with a higher elastic modulus than that of tread rubber is disposed in a tire radial region including at least an opening to the tread surface of a wall defining the widthwise sipe. Microfabrication is applied in a region of the tread surface surrounding at least a portion of the opening of the widthwise sipe to the tread surface.

A modified conjugated diene rubber having a modifying structure derived from a siloxane compound at at least one terminal of a polymer chain containing conjugated diene monomer unit and a monomer unit of a vinyl compound having a functional group interactive with silica.

The present disclosure provides a tire which makes it possible to reduce the increase in hardness and the decrease in wet grip performance from before to after heat aging. The present disclosure relates to a tire including a tread, the tread including an elastomer composition containing a styrene elastomer and urethane particles, the tread satisfying the following relationship (1): (M100a−M100f)/M100f×100≤38 wherein M100f represents the stress at 100% elongation (23° C.) before heat aging, and M100a represents the stress at 100% elongation (23° C.) after heat aging.

A tread comprising a plurality of grooves and manufactured using a rubber compound comprising at least one cross-linkable unsaturated chain polymeric base, a filler, a vulcanization system and a wax comprising at least 50% by weight nonacosandiols. At least part of said grooves has a hydrophobic surface structure comprising a plurality of protruding elements.

The tread has a contact face that is provided with at least one circumferential groove and a transverse grooves opening to the contact face and delimiting contact elements. The tread has a center region and shoulder regions and is provided with at least one compressive contact element among the contact elements. A volumetric void ratio of the compressive contact element in a unit region surrounded by a center of the at least one circumferential groove and a center of the transverse grooves delimiting the compressive contact element is at least equal to 25%. An aspect ratio, which is defined as a ratio of a surface of the compressive contact element supposed to contact with ground divided by a sum of a surface area of the compressive contact element touching with air other than the surface of the compressive contact element supposed to contact with ground, is at most 70%.

Provided is a tire comprising a tread, wherein a ratio of a tire weight G (kg) to a maximum bad capacity W.sub.L (kg) of the tire (G/W.sub.L) is 0.0150 or less, wherein the tread has at least one rubber layer formed of a rubber composition comprising a rubber component and a reinforcing filler, and wherein a tan at 30° C. of the rubber composition is 0.15 or less, and a complex elastic modulus at 30° C. (E*.sub.30) of the rubber composition is 8.0 MPa or less.

The present invention relates to a method for the preparation of a synthetic rubber blend, wherein the blend comprises a high molecular weight polydiene (A) and a low molecular weight polydiene (B). The present invention further relates to a synthetic rubber blend obtainable according to the method described herein; as well as to rubber compositions comprising the blend; and articles, such as tires.

A tire comprises a tread portion having a tread surface and buttress surfaces. The buttress surfaces have inclinations such that the tread edges shift axially outwards as the tread portion is worn off. The tread rubber includes a radially outermost first rubber layer and a radially inner second rubber layer. The loss tangent δ2 of the second rubber layer is larger than the loss tangent δ1 of the first rubber layer. One of or each of the buttress surfaces is provided with an outer lateral groove. The outer lateral groove is located axially outside the tread edge when the tire is new, and when the tread portion is worn off and the tread edge shifts axially outward, the outer lateral groove is at least partially located axially inward of the tread edge.