US-20260125542-A1 - A RUBBER COMPOSITION

Abstract

A rubber composition, which allows unexpectedly improved tearability performance while having maintained or improved hysteresis performance, is based on at least an elastomer matrix, a reinforcing filler, a plasticizing agent, and a crumb rubber. A ratio by weight of the total amount of the reinforcing filler to that of the plasticizing agent is less than 4.50. The total amount of the reinforcing filler and the crumb rubber is more than 30 phr and less than 70 phr. A ratio by weight of the total amount of the crumb rubber to that of the reinforcing filler is more than 0.20 and less than 2.50.

Inventors

• Yoshiko MAETA
• Sylvain Mayer
• Aline Riou

Assignees

• COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN

Dates

Publication Date

20260507

Application Date

20211029

Claims (16)

1. 1 .- 15 . (canceled)
2. 16 . A rubber composition based on at least: an elastomer matrix; a reinforcing filler; a plasticizing agent; and a crumb rubber, wherein a ratio by weight of a total amount of the reinforcing filler to a total amount of the plasticizing agent is less than 4.50, wherein a total amount of the reinforcing filler and the crumb rubber is more than 30 phr and less than 70 phr, and wherein a ratio by weight of a total amount of the crumb rubber to the total amount of the reinforcing filler is more than 0.20 and less than 2.50.
3. 17 . The rubber composition according to claim 16 , wherein the elastomer matrix comprises at least one elastomer selected from the group consisting of an isoprene elastomer and a butadiene elastomer.
4. 18 . The rubber composition according to claim 16 , wherein the elastomer matrix comprises at least one isoprene elastomer.
5. 19 . The rubber composition according to claim 16 , wherein the elastomer matrix comprises at least one butadiene elastomer.
6. 20 . The rubber composition according to claim 16 , wherein the elastomer matrix comprises at least one isoprene elastomer and at least one butadiene elastomer.
7. 21 . The rubber composition according to claim 16 , wherein the reinforcing filler comprises at least one carbon black, and wherein a total amount of the carbon black is more than 50% by weight per 100% by weight of the reinforcing filler.
8. 22 . The rubber composition according to claim 16 , wherein the total amount of the reinforcing filler is more than 5 phr and less than 55 phr.
9. 23 . The rubber composition according to claim 16 , wherein the plasticizing agent is selected from the group consisting of liquid plasticizing agents, hydrocarbon resins and combinations thereof.
10. 24 . The rubber composition according to claim 16 , wherein a total amount of the plasticizing agent is more than 2 phr.
11. 25 . The rubber composition according to claim 16 , wherein a ratio by weight of the total amount of the reinforcing filler to a total amount of the plasticizing agent is more than 1.50.
12. 26 . The rubber composition according to claim 16 , wherein the crumb rubber does not comprise any crumb rubber particles remaining on a 40 mesh sieve, or the crumb rubber comprises crumb rubber particles remaining on a 40 mesh sieve and a total amount of the crumb rubber particles remaining on the 40 mesh sieve is less than 10% by weight per 100% by weight of the crumb rubber.
13. 27 . The rubber composition according to claim 16 , wherein the total amount of the crumb rubber is more than 5 phr and less than 33 phr.
14. 28 . The rubber composition according to claim 16 , wherein the crumb rubber has not undergone any modification by a treatment selected from the group consisting of thermal, mechanical, biological, and chemical treatments and combinations thereof.
15. 29 . The rubber composition according to claim 16 , wherein the rubber composition is further based on an anti-ozone wax.
16. 30 . A rubber product comprising the rubber composition according to claim 16 .

Description

TECHNICAL FIELD The field of the invention is that of rubber compositions, particularly rubber compositions for rubber products, more particularly rubber compositions for rubber products coming into contact with the ambient air, still more particularly rubber compositions for tires, shoes, conveyor belts or rubber tracks, especially rubber compositions for tires, more especially rubber compositions for tire sidewalls. BACKGROUND Rubber products such as tires can be teared by continuous deformation, contact with irregularities or both. CITATION LIST Patent Literature [PTL 1] WO2021/153643 The patent literature 1 discloses a rubber composition for a sidewall of a tire, which comprises a rubber component, a carbon black, a silica, a silane coupling agent and short fibers, and which exhibits excellent tearability performance that is resistance to failure due to dynamic flexing and abrasion of rubber compositions for the rubber articles. A constant objective of manufacturers for rubber products is to improve tearability performance without degrading hysteresis performance, preferably while improving hysteresis performance. SUMMARY OF INVENTION Technical Problem During their research, the inventors have discovered that a specific rubber composition intended in particular for a rubber product, in more particular for a tire, a shoe, a conveyor belt or a rubber track, in still more particular for a tire sidewall, which allows unexpectedly improved tearability performance while being maintained or improved hysteresis performance. The expression “based on” or “composition based on” should be understood as meaning a composition comprising the mixture, the product of the in situ reaction of the various base constituents used or both, some of these constituents being able to react, being intended to react, or being intended to react and being to react with one another, at least partially, during the various phases of manufacture of the composition or during the subsequent curing, modifying the composition as it is prepared at the start. Thus, the compositions as employed for the invention can be different in the non-crosslinked state and in the crosslinked (vulcanized) state. The term “phr” means part by weight per hundred parts of elastomers, within the meaning of the preparation of the composition before curing. That is to say, in the case of the presence of a crumb rubber, that the term “phr” means part by weight per hundred parts of “new” elastomers, thus excluding from the base 100 the elastomers contained in the crumb rubber. In the present description, unless expressly stated otherwise, all the percentages (%) indicated are percentages by weight (wt %). The expression “elastomer matrix” is understood to mean, in a given composition, all of the elastomers present in said rubber composition. In the present description, unless expressly indicated otherwise, each TgDSC (glass transition temperature) is measured in a known way by DSC (Differential Scanning Calorimetry) according to Standard ASTM D3418-08. Any interval of values denoted by the expression “between a and b” represents the range of values of more than “a” and of less than “b” (i.e. the limits a and b excluded) whereas any interval of values denoted by the expression “from a to b” means the range of values going from “a” to “b” (i.e. including the strict limits a and b). When reference is made to a “predominant” compound, this is understood to mean, within the meaning of the present invention, that this compound is predominant among the compounds of the same type in the composition, that is to say that it is the one which represents the greatest amount by weight among the compounds of the same type, and preferably more than 50% by weight, more preferably more than 75% by weight. Thus, for example, a predominant polymer is the polymer representing the greatest weight, with respect to the total weight of the polymers in the composition. In the same way, a “predominant” filler is the one representing the greatest weight among the fillers of the composition. By way of example, in a system comprising just one polymer, the latter is predominant within the meaning of the present invention and, in a system comprising two polymers, the predominant polymer represents more than half of the weight of the polymers. On the contrary, a “minor” compound is a compound which does not represent the greatest fraction by weight among the compounds of the same type. Within the meaning of the present invention, when reference is made to a “predominant” unit (or monomer) within one and the same compound (or polymer), this is understood to mean that this unit (or monomer) is predominant among the units (or monomers) forming the compound (or polymer), that is to say that it is the one which represents the greatest fraction by weight among the units (or monomers) forming the compound (or polymer). Thus, for example, a resin predominantly composed of units resulting from C5 monomers i