US 12,311,626 B2Granted

Process for the manufacture of a multi-compound tread for pneumatic tires for road vehicles

AssigneeBridgestone Europe NV/SA

InventorsEnrico Fresch, Alessandra Bartoloni, Andrea Sabella

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Abstract

A process for the manufacture of a tread band for pneumatic tyres, wherein the blocks thereof comprise different rubber portions characterized by a different hysteresis loss. The process comprises a shredding step, wherein from a first and from a second rubber tread compound a plurality of fragments is manufactured with dimensions of between 6 and 30 mesh; a mixing step, wherein the fragments from the first and second compound are mixed together in order to obtain a mixture wherein the fragments are distributed in a random manner and retain their chemical/physical individuality; and an extrusion step, wherein the mixture from the preceding step is extruded for the manufacture of the tread band. The first and second compounds have different dynamic properties in terms of: dynamic modulus at 30° C., tanδ at 0° C., tanδ at 30° C. and tanδ at 60° C. The fragments retain a chemical/physical individuality both within the mixture formed during the mixing step and within the tread band formed during the extrusion step.

Claims8

Dependent claims

A method for manufacturing a tread band for pneumatic tires wherein blocks thereof comprise portions with differing hysteresis losses, the method comprising:

shredding a first rubber tread compound and a second rubber tread compound to produce a plurality of fragments of the first rubber tread compound and a plurality of fragments of the second rubber tread compound with dimensions of between 6 and 30 mesh;
mixing the plurality of fragments of the first rubber tread compound together with the plurality of fragments of the second rubber tread compound to obtain a mixture wherein said fragments are distributed in a random manner and retain their chemical/physical individuality in the tread band and are joined to one another without merging;
and
extruding the mixture from the mixing step to form the tread band wherein said fragments from, respectively, said first rubber tread compound and said second rubber tread compound are distributed randomly and retain their chemical/physical individuality in the tread band and are joined to one another without merging;
and wherein said first rubber tread compound and said second rubber tread compound have different dynamic properties with respect to each of:
dynamic modulus at 30° C.;
tan δ at °0 C;
tan δ at 30° C.;
and tan δ at 60° C.;
wherein the first rubber tread compound comprises a rubber component of 100 parts per hundred (phr) S-SBR, and the second rubber tread compound comprises a rubber component of 80 phr S-SBR and 20 phr E-SBR.

7 more elements

A tread band for pneumatic tires wherein blocks thereof comprise portions with differing hysteresis losses, manufactured by:

shredding a first rubber tread compound and a second rubber tread compound to produce a plurality of fragments of the first rubber tread compound and a plurality of fragments of the second rubber tread compound with dimensions of between 6 and 30 mesh;
mixing the plurality of fragments of the first rubber tread compound together with the plurality of fragments of the second rubber tread compound to obtain a mixture wherein said fragments are distributed in a random manner and retain their chemical/physical individuality in the tread band and are joined to one another without merging;
and
extruding the mixture from the mixing step to form the tread band wherein said fragments from, respectively, said first rubber tread compound and said second rubber tread compound are distributed randomly and retain their chemical/physical individuality in the tread band and are joined to one another without merging;
wherein said first rubber tread compound and said second rubber tread compound have different dynamic properties with respect to each of:
dynamic modulus at 30° C.;
tan δ at 30° C.;
tan δ at 30° C.;
and tan δ at 60° C.;
and wherein the first rubber tread compound comprises a rubber component of 100 parts per hundred (phr)S-SBR, and the second rubber tread compound comprises a rubber component of 80 phr S-SBR and 20 phr E-SBR.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/795,613Filed 26 Jan 2021
Priority: IT 10202000000161228 Jan 2020
Published: US 2023/0078465 A116 Mar 2023
Granted: 27 May 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification26 codes

B29D 30/52
Pneumatic tyres or parts thereof: unvulcanised treads, e.g. on used tyres; Retreading
B29B 7/726
Measuring, controlling or regulating: measuring properties of mixture, e.g. temperature or density
B29B 7/7466
Using other mixers or combinations of mixers, e.g. of dissimilar mixers ; Plant: combinations of similar mixers
B29B 7/7495
Systems, i.e. flow charts or diagrams; Plants: for mixing rubber