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JP-7855164-B2 - tire

JP7855164B2JP 7855164 B2JP7855164 B2JP 7855164B2JP-7855164-B2

Inventors

  • 竹部 朝香
  • 中村 健太郎

Assignees

  • 住友ゴム工業株式会社

Dates

Publication Date
20260508
Application Date
20220624

Claims (20)

  1. A tire having a tread section, The cap rubber layer that forms the tread portion The rubber component contains 40 parts by mass or less of styrene-butadiene rubber (SBR) with a styrene content of 25% by mass or less per 100 parts by mass. Under conditions of temperature -30°C, frequency 10Hz, initial strain 5%, and dynamic strain rate 1%, the loss loss tangent (-30°C tanδ) measured in the deformation mode: tensile is 0.10 or greater. The rubber composition is formed from a rubber composition in which the loss tangent (0°C tanδ), measured under the conditions of temperature 0°C, frequency 10 Hz, initial strain 5%, and dynamic strain rate 1%, is 0.30 or greater in the deformation mode: tensile. The thickness T of the tread portion is 10 mm or more and 20 mm or less. Furthermore, the tire is characterized in that the thickness T (mm) of the tread portion and the -30 °C t anδ of the cap rubber layer satisfy the following formula. -30℃tanδ/T≧0.022
  2. A tire having a tread section, The cap rubber layer that forms the tread portion The rubber component contains 40 parts by mass or less of styrene-butadiene rubber (SBR) with a styrene content of 25% by mass or less per 100 parts by mass. It is formed from a rubber composition in which the loss loss tangent (-30°C tanδ), measured under the conditions of temperature -30°C, frequency 10 Hz, initial strain 5%, and dynamic strain rate 1%, in the deformation mode: tensile, is 0.10 or greater. The thickness T of the tread portion is 10 mm or more and 20 mm or less. Furthermore, the thickness T (mm) of the tread portion and the -30 °C t anδ of the cap rubber layer satisfy the following formula: The tread portion is formed from the cap rubber layer and the base rubber layer provided inside the cap rubber layer. A tire characterized in that the loss tangent (30°C tanδ) of the base rubber layer, measured at a temperature of 30°C, a frequency of 10Hz, an initial strain of 5%, a dynamic strain of 1%, and a deformation mode of tensile, is greater than the loss tangent (30°C tanδ) of the cap rubber layer, measured in the same manner . -30℃tanδ/T≧0.022
  3. A tire having a tread section, The cap rubber layer that forms the tread portion The rubber component contains 40 parts by mass or less of styrene-butadiene rubber (SBR) with a styrene content of 25% by mass or less per 100 parts by mass. It is formed from a rubber composition in which the loss loss tangent (-30°C tanδ), measured under the conditions of temperature -30°C, frequency 10 Hz, initial strain 5%, and dynamic strain rate 1%, in tensile deformation mode, is 0.10 or greater. The thickness T of the tread portion is 10 mm or more and 20 mm or less. Furthermore, the thickness T (mm) of the tread portion and the -30 °C t anδ of the cap rubber layer satisfy the following formula: The tread portion is formed from the cap rubber layer and the base rubber layer provided inside the cap rubber layer. A tire characterized in that the complex modulus of elasticity of the base rubber layer, measured at a temperature of 30°C, a frequency of 10Hz, an initial strain of 5%, a dynamic strain of 1%, and a deformation mode of elongation, is greater than the complex modulus of elasticity of the cap rubber layer, similarly measured at -30°C . -30℃tanδ/T≧0.022
  4. A tire having a tread section, The cap rubber layer that forms the tread portion The rubber component contains 40 parts by mass or less of styrene-butadiene rubber (SBR) with a styrene content of 25% by mass or less per 100 parts by mass. It is formed from a rubber composition in which the loss loss tangent (-30°C tanδ), measured under the conditions of temperature -30°C, frequency 10 Hz, initial strain 5%, and dynamic strain rate 1%, in the deformation mode: tensile, is 0.50 or greater. The thickness T of the tread portion is 10 mm or more and 20 mm or less. Furthermore, the tire is characterized in that the thickness T (mm) of the tread portion and the -30 °C t anδ of the cap rubber layer satisfy the following formula. -30℃tanδ/T >0.04
  5. The tire according to any one of claims 1 to 4, characterized in that the content of styrene-butadiene rubber (SBR) is 35 parts by mass or less.
  6. The tire according to any one of claims 1 to 3, characterized in that the -30°C tanδ of the cap rubber layer is 0.50 or more.
  7. The tire according to any one of claims 1 to 4, characterized in that the -30°C tanδ of the cap rubber layer is 0.65 or more.
  8. The tire according to any one of claims 2 to 4, characterized in that the loss tangent (0°C tanδ) measured in the deformation mode: tensile under the conditions of a temperature of 0°C, a frequency of 10 Hz, an initial strain of 5%, and a dynamic strain of 1% in the cap rubber layer is 0.30 or more.
  9. The tire according to any one of claims 1 to 4, characterized in that the loss tangent (0°C tanδ) measured in the deformation mode: tensile under the conditions of a temperature of 0°C, a frequency of 10 Hz, an initial strain of 5%, and a dynamic strain of 1% in the cap rubber layer is 0.35 or more.
  10. The tire according to claim 9 , characterized in that the tanδ of the cap rubber layer at 0°C is 0.45 or more.
  11. The tire according to any one of claims 1 to 4, characterized in that the loss tangent (30°C tanδ) measured in the deformation mode: tensile under the conditions of a temperature of 30°C, a frequency of 10Hz, an initial strain of 5%, and a dynamic strain of 1% in the cap rubber layer is 0.20 or less.
  12. The tire according to claim 11 , characterized in that the 30°C tanδ of the cap rubber layer is 0.13 or less.
  13. The tire according to any one of claims 1 to 4, characterized in that the thickness T of the tread portion is 12 mm or more and 18 mm or less.
  14. The tire according to any one of claims 1 to 3, characterized in that the thickness T (mm) of the tread portion and the -30 °C tanδ of the cap rubber layer satisfy the following formula. -30℃tan/T>0.04
  15. The tire according to any one of claims 1 to 4, characterized in that the glass transition temperature (Tg) of the cap rubber layer is -40°C or lower.
  16. The tire according to claim 1 or 4 , characterized in that the tread portion is formed from the cap rubber layer and a base rubber layer provided inside the cap rubber layer.
  17. The tread portion is formed from the cap rubber layer and the base rubber layer provided inside the cap rubber layer. The tire according to any one of claims 1 to 4, characterized in that the thickness of the cap rubber layer is 50% or more of the total thickness of the tread portion.
  18. The tread portion is formed from the cap rubber layer and the base rubber layer provided inside the cap rubber layer. The tire according to any one of claims 1, 3, or 4 , characterized in that the 30°C tanδ in the base rubber layer is greater than the 30°C tanδ in the cap rubber layer.
  19. The tread portion is formed from the cap rubber layer and the base rubber layer provided inside the cap rubber layer. The tire according to any one of claims 1, 2, or 4, characterized in that the complex modulus of elasticity of the base rubber layer, measured at a temperature of 30°C, a frequency of 10Hz, an initial strain of 5%, a dynamic strain of 1%, and a deformation mode of extension, is greater than the complex modulus of elasticity of the cap rubber layer, similarly measured at -30°C.
  20. The tire according to any one of claims 1 to 4, characterized in that the cap rubber layer contains a resin component selected from the group consisting of rosin resin, styrene resin, coumarone resin, terpene resin, C5 resin, C9 resin, C5C9 resin, and acrylic resin.

Description

This invention relates to tires. Tires require high braking performance (grip performance) for safety reasons, and various technologies have been proposed to improve grip performance (for example, Patent Documents 1-3). Japanese Patent Publication No. 2011-93386Japanese Patent Publication No. 2013-79017Japanese Patent Publication No. 2016-37100 [1] Features of the tire according to the present invention First, the features of the tire according to the present invention will be explained. The tire according to the present invention is a tire having a tread portion, wherein the cap rubber layer forming the tread portion contains 40 parts by mass or less of SBR with a styrene content of 25% by mass or less per 100 parts by mass of rubber component, and the loss tangent (-30°C tanδ) measured in tensile deformation mode under the conditions of temperature -30°C, frequency 10 Hz, initial strain 5%, and dynamic strain rate 1% is 0.10 or more, and the loss tangent (0°C tanδ) measured in tensile deformation mode under the conditions of temperature 0°C, frequency 10 Hz, initial strain 5%, and dynamic strain rate 1% is 0.30 or more . The thickness of the tread portion is 10 mm or more and 20 mm or less. Furthermore, the ratio of the -30 °C tanδ of the cap rubber layer to the tread thickness T (mm) (-30°C tanδ/T ) is 0.022 or greater. Furthermore, the term "cap rubber layer" as used herein is not limited to the cap rubber layer forming the outermost layer of the tread. If there are two or more layers within 5 mm from the tread surface inward, it is sufficient that at least one of these layers satisfies the requirements of the aforementioned rubber composition. These features, as described later, allow for improved grip performance on icy and snowy roads. 2. Mechanism of Effect in the Tire According to the Present Invention The mechanism of effect described above in the tire according to the present invention is thought to be as follows. As described above, the tire cap rubber layer according to the present invention contains 40 parts by mass or less of SBR with a styrene content of 25% by mass or less per 100 parts by mass of rubber component. SBR with a low styrene content, specifically 25% by mass or less, has a low glass transition temperature (Tg). By incorporating such low-styrene SBR into the rubber component, the rubber can maintain its softness even at low temperatures, improving its ability to conform to icy and snowy road surfaces. At the same time, by including 40 parts by mass or less of SBR with a low styrene content (styrene content of 25% by mass or less), minute styrene domains can be appropriately formed on the rubber surface, making it easier to grip the road surface. Furthermore, the presence of minute styrene domains generates friction with other polymer molecular chains, allowing for moderate heat generation even at low temperatures. This is thought to facilitate friction on icy and snowy road surfaces. Additionally, these minute styrene domains can provide a scratching effect on icy and snowy surfaces. Furthermore, the amount of styrene is more preferably 20% by mass or less, and even more preferably 15% by mass or less. On the other hand, the lower limit is preferably 4% by mass or more, more preferably 5% by mass or more, and even more preferably 6% by mass or more. Furthermore, in this invention, "containing 40 parts by mass or less of SBR with a styrene content of 25% by mass or less per 100 parts by mass of the rubber component" means that the amount of SBR in 100 parts by mass of the rubber component is 40 parts by mass or less, and the total amount of styrene in the SBR is 25% by mass or less. In other words, when a styrene-containing polymer (SBR) is contained alone in the rubber component, it indicates that the amount of styrene is 25% by mass or less. When multiple styrene-containing polymers (SBRs) are contained in the rubber component, it indicates that the total amount of styrene, calculated by the product of the amount of styrene (by mass) in each polymer and the amount of that polymer blended per 100 parts by mass of the rubber component (parts by mass), is 25% by mass or less. More specifically, if 100 parts by mass of rubber component contain SBR1 (X1 parts by mass) with a styrene content of S1% by mass and SBR2 (X2 parts by mass) with a styrene content of S2% by mass, then the amount of styrene calculated from the formula {(S1 × X1) + (S2 × X2)} / (X1 + X2) is 25% by mass or less. Furthermore, in the rubber composition after vulcanization, the amount of styrene contained in the rubber component after acetone extraction can also be calculated by determining it using solid-state nuclear magnetic resonance (Solid-state NMR) or Fourier transform infrared spectrophotometer (FTIR). In this invention, the loss tangent (-30°C tanδ) of the rubber composition forming the cap rubber layer, measured under the conditions of a temperature of -30°C, a frequency of 10 Hz, an initial strain of 5%