US 12,311,626 B2
Process for the manufacture of a multi-compound tread for pneumatic tires for road vehicles
Enrico Fresch, Rome (IT); Alessandra Bartoloni, Rome (IT); and Andrea Sabella, Rome (IT)
Assigned to Bridgestone Europe NV/SA, Zaventem (BE)
Appl. No. 17/795,613
Filed by Bridgestone Europe NV/SA [BE/BE], Zaventem (BE)
PCT Filed Jan. 26, 2021, PCT No. PCT/IB2021/050579
§ 371(c)(1), (2) Date Jul. 27, 2022,
PCT Pub. No. WO2021/152452, PCT Pub. Date Aug. 5, 2021.
Claims priority of application No. 102020000001612 (IT), filed on Jan. 28, 2020.
Prior Publication US 2023/0078465 A1, Mar. 16, 2023
Int. Cl. B29D 30/52 (2006.01); B60C 11/00 (2006.01)
CPC B29D 30/52 (2013.01) [B60C 11/0008 (2013.01); B60C 11/005 (2013.01); B60C 2011/0025 (2013.01)] 8 Claims
OG exemplary drawing
 
1. 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.
 
5. 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.