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US-20260125520-A1 - RUBBER MATERIAL AND MANUFACTURING METHOD OF THE SAME, AND TIRE

US20260125520A1US 20260125520 A1US20260125520 A1US 20260125520A1US-20260125520-A1

Abstract

A rubber material that allows for obtaining a rubber member that is excellent in mechanical properties and low loss property by utilizing rubber powder. A rubber material includes rubber powder (A) dispersed in a rubber base material (B), wherein the rubber powder (A) includes an unvulcanized rubber layer (a2) disposed on the surface of a vulcanized rubber powder (a1), and the unvulcanized rubber layer (a2) includes a crosslinking agent.

Inventors

  • Ashoke Kumar KARMOKAR
  • Masahiro Homma
  • Ayaka NISHIMURA

Assignees

  • BRIDGESTONE CORPORATION

Dates

Publication Date
20260507
Application Date
20230728
Priority Date
20221031

Claims (20)

  1. 1 . A rubber material comprising rubber powder (A) dispersed in a rubber base material (B), the rubber powder (A) comprising an unvulcanized rubber layer (a2) disposed on a surface of a vulcanized rubber powder (a1), and the unvulcanized rubber layer (a2) comprising a crosslinking agent.
  2. 2 . The rubber material according to claim 1 , wherein M1/M2 is 0.5 or more and 2.5 or less, where M1 represents a mass of the vulcanized rubber powder (a1) and M2 represents a mass of the unvulcanized rubber layer (a2) in the rubber powder (A).
  3. 3 . The rubber material according to claim 1 , wherein the unvulcanized rubber layer (a2) comprises sulfur as the crosslinking agent.
  4. 4 . The rubber material according to claim 1 , wherein the unvulcanized rubber layer (a2) comprises a diene-based rubber.
  5. 5 . The rubber material according to claim 4 , wherein the unvulcanized rubber layer (a2) comprises natural rubber as the diene-based rubber, and a proportion of the natural rubber in a rubber component is 50 mass % or more.
  6. 6 . A tire comprising a vulcanized product of the rubber material according to claim 1 .
  7. 7 . A manufacturing method of the rubber material according to claim 1 , the method comprising: a pre-kneading step of kneading the vulcanized rubber powder (a1) and a rubber component for the unvulcanized rubber layer (a2) to obtain a master batch, which is the precursor of the rubber powder (A); and a main kneading step of kneading the master batch and a rubber component for the rubber base material (B) so that the rubber powder (A) formed through fine pulverization of the master batch is dispersed in the rubber base material (B).
  8. 8 . The rubber material according to claim 2 , wherein the unvulcanized rubber layer (a2) comprises sulfur as the crosslinking agent.
  9. 9 . The rubber material according to claim 2 , wherein the unvulcanized rubber layer (a2) comprises a diene-based rubber.
  10. 10 . The rubber material according to claim 9 , wherein the unvulcanized rubber layer (a2) comprises natural rubber as the diene-based rubber, and a proportion of the natural rubber in a rubber component is 50 mass % or more.
  11. 11 . A tire comprising a vulcanized product of the rubber material according to claim 2 .
  12. 12 . A manufacturing method of the rubber material according to claim 2 , the method comprising: a pre-kneading step of kneading the vulcanized rubber powder (a1) and a rubber component for the unvulcanized rubber layer (a2) to obtain a master batch, which is the precursor of the rubber powder (A); and a main kneading step of kneading the master batch and a rubber component for the rubber base material (B) so that the rubber powder (A) formed through fine pulverization of the master batch is dispersed in the rubber base material (B).
  13. 13 . The rubber material according to claim 3 , wherein the unvulcanized rubber layer (a2) comprises a diene-based rubber.
  14. 14 . The rubber material according to claim 13 , wherein the unvulcanized rubber layer (a2) comprises natural rubber as the diene-based rubber, and a proportion of the natural rubber in a rubber component is 50 mass % or more.
  15. 15 . A tire comprising a vulcanized product of the rubber material according to claim 3 .
  16. 16 . A manufacturing method of the rubber material according to claim 3 , the method comprising: a pre-kneading step of kneading the vulcanized rubber powder (a1) and a rubber component for the unvulcanized rubber layer (a2) to obtain a master batch, which is the precursor of the rubber powder (A); and a main kneading step of kneading the master batch and a rubber component for the rubber base material (B) so that the rubber powder (A) formed through fine pulverization of the master batch is dispersed in the rubber base material (B).
  17. 17 . A tire comprising a vulcanized product of the rubber material according to claim 4 .
  18. 18 . A manufacturing method of the rubber material according to claim 4 , the method comprising: a pre-kneading step of kneading the vulcanized rubber powder (a1) and a rubber component for the unvulcanized rubber layer (a2) to obtain a master batch, which is the precursor of the rubber powder (A); and a main kneading step of kneading the master batch and a rubber component for the rubber base material (B) so that the rubber powder (A) formed through fine pulverization of the master batch is dispersed in the rubber base material (B).
  19. 19 . A tire comprising a vulcanized product of the rubber material according to claim 5 .
  20. 20 . A manufacturing method of the rubber material according to claim 5 , the method comprising: a pre-kneading step of kneading the vulcanized rubber powder (a1) and a rubber component for the unvulcanized rubber layer (a2) to obtain a master batch, which is the precursor of the rubber powder (A); and a main kneading step of kneading the master batch and a rubber component for the rubber base material (B) so that the rubber powder (A) formed through fine pulverization of the master batch is dispersed in the rubber base material (B).

Description

TECHNICAL FIELD The present disclosure relates to a rubber material and a manufacturing method of the same, and a tire. BACKGROUND Currently, investigations are underway on the utilization of rubber powder (vulcanized rubber powder) obtained from waste rubber and used tires. For example, PTL 1 discloses that a material containing rubber powder, which can also be obtained from waste materials of used vulcanized rubber products, along with certain bone material and binder, exhibits excellent wear resistance and slip resistance after wear due to use, and can be used as an elastic paving material for sidewalks and the like. CITATION LIST Patent Literature PTL 1: JP 2010-242430 A SUMMARY Technical Problem Here, it is also desired to utilize the above-described rubber powder, for example, in the manufacturing of tires. However, investigations conducted by the present inventor have found that a rubber material merely obtained by blending and kneading the above-described rubber powder into a rubber component is not sufficient in terms of achieving the performance required for tire components, particularly in balancing at least mechanical properties and low loss property, leaving room for improvement. Accordingly, the present disclosure is directed to solving the above-mentioned problem of the conventional art and to providing a rubber material that allows for obtaining a rubber member that is excellent in mechanical properties and low loss property by utilizing rubber powder and a manufacturing method of the same, as well as a tire using that rubber material. Solution to Problem The main features of the present disclosure for solving the above problem are as follows. [1]A rubber material comprising rubber powder (A) dispersed in a rubber base material (B),the rubber powder (A) comprising an unvulcanized rubber layer (a2) disposed on a surface of a vulcanized rubber powder (a1), and the unvulcanized rubber layer (a2) comprising a crosslinking agent.[2] The rubber material according to [1], wherein M1/M2 is 0.5 or more and 2.5 or less, where M1 represents a mass of the vulcanized rubber powder (a1) and M2 represents a mass of the unvulcanized rubber layer (a2) in the rubber powder (A).[3] The rubber material according to [1] or [2], wherein the unvulcanized rubber layer (a2) comprises sulfur as the crosslinking agent.[4] The rubber material according to any one of [1] to [3], wherein the unvulcanized rubber layer (a2) comprises a diene-based rubber.[5] The rubber material according to [4], wherein the unvulcanized rubber layer (a2) comprises natural rubber as the diene-based rubber, and a proportion of the natural rubber in a rubber component is 50 mass % or more.[6]A tire comprising a vulcanized product of the rubber material according to any one of [1] to [5].[7]A manufacturing method of the rubber material according to any one of [1] to [5], the method comprising:a pre-kneading step of kneading the vulcanized rubber powder (a1) and a rubber component for the unvulcanized rubber layer (a2) to obtain a master batch, which is the precursor of the rubber powder (A); anda main kneading step of kneading the master batch and a rubber component for the rubber base material (B) so that the rubber powder (A) formed through fine pulverization of the master batch is dispersed in the rubber base material (B). Advantageous Effect According to the present disclosure, it is possible to obtain a rubber material that allows for obtaining a rubber member that is excellent in mechanical properties and low loss property by utilizing rubber powder and a manufacturing method of the same, as well as a tire using the rubber material. DETAILED DESCRIPTION Hereinafter, the present disclosure will be illustrated and explained in detail based on an embodiment. Note that the compounds described in this specification may be partially or entirely derived from fossil resources, biological resources such as plant resources, or recycled resources such as used tires. Alternatively, they may be derived from a mixture of two or more of fossil resources, biological resources, and recycled resources. (Rubber Material) A rubber material of one embodiment of the present disclosure (hereinafter sometimes referred to as “the rubber material of the present embodiment”) is a rubber material comprising rubber powder (A) dispersed in a rubber base material (B). In the rubber material of the present embodiment, the rubber powder (A) is characterized in that an unvulcanized rubber layer (a2) is disposed on the surface of vulcanized rubber powder (a1), and that the unvulcanized rubber layer (a2) contains a crosslinking agent. According to the rubber material of the present embodiment, it is possible to obtain a rubber component that is excellent in mechanical properties and low loss property by utilizing rubber powder. It should be noted that, in the present specification, the term “rubber material” refers to a material containing at least a rubber component. The