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EP-4360904-B1 - TIRE

EP4360904B1EP 4360904 B1EP4360904 B1EP 4360904B1EP-4360904-B1

Inventors

  • DOHATA, Yuki
  • ONOUE, SHINGO
  • SAITO, KOSUKE

Dates

Publication Date
20260513
Application Date
20220322

Claims (8)

  1. A tire comprising a reinforcement layer (6a, 6b) comprising a reinforcing material and a vulcanized rubber covering the reinforcing material, wherein the vulcanized rubber is a vulcanized rubber of a rubber composition containing N-cyclohexyl-2-benzothiazolylsulfenamide, the content of N-cyclohexyl-2-benzothiazolylsulfenamide is 0.4 parts by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the rubber component, the reinforcing material contains a metal where a steel cord surface is covered with a ternary plating of copper, zinc, and iron, the reinforcement layer (6a, 6b) is arranged on the inside of a tread surface in a tire radial direction, and a ratio (a/b) of a modulus (a) at 50 % elongation of the vulcanized rubber covering the reinforcing material in a central portion of the reinforcement layer in a tire width direction (6C), measured by a tensile test at room temperature (25 °C) according to JIS K6251:2017, and a modulus (b) at 50 % elongation of the vulcanized rubber covering the reinforcing material in an end portion of the reinforcement layer in a tire width direction (6E), measured by a tensile test at room temperature (25 °C) according to JIS K6251:2017, is 0.94 or more and 1.06 or less.
  2. The tire according to claim 1, wherein an amount of the iron in the covering is 1 % by mass or more and less than 10 % by mass of a total mass of the copper, the zinc, and the iron.
  3. The tire according to claim 1 or 2, wherein an amount of phosphorus in the covering is more than 0 mg/m 2 and 4 mg/m 2 or less.
  4. The tire according to any one of claims 1 to 3, wherein the steel cord is drawn by diamond dies.
  5. The tire according to any one of claims 1 to 4, wherein the rubber composition contains a rubber component containing 50 % by mass or more of a polyisoprene-based rubber.
  6. The tire according to any one of claims 1 to 5, wherein the rubber composition has a cobalt-containing compound content of 0.01 % by mass or less.
  7. The tire according to any one of claims 1 to 6, wherein the rubber composition contains an alkylphenol resin.
  8. The tire according to any one of claims 1 to 7, wherein a content of cobalt atoms is 1 % by mass or less.

Description

TECHNICAL FIELD This disclosure relates to a tire. BACKGROUND In a tire, a reinforcement layer obtained by covering a reinforcing material such as a metal cord with rubber is generally arranged as a belt on the inside of a tread surface of the tire in the tire radial direction and on the outside of a crown portion of a carcass in the tire radial direction to improve the durability of the tire (see JP 2017-31240 A (PTL 1)). When manufacturing a tire, a reinforcing material-rubber composite is usually prepared in advance by covering a reinforcing material with rubber, and in a green tire molding process, the reinforcing material-rubber composite is laminated together with another rubber member to be incorporated into a green tire, and then a vulcanization process is performed to obtain a part of a tire (reinforcement layer). Further, WO/2020/156967 A1 (PTL 2) describes a steel cord with a brass coating enriched with iron particles that allows the use of tertiary alloy coating even with a cobalt-free compound. CITATION LIST Patent Literature PTL 1: JP 2017-31240 APTL 2: WO/2020/156967 A1 SUMMARY (Technical Problem) However, the tire vulcanization process of PTL 1 requires to perform vulcanization at as high a temperature as possible for a short time to improve the productivity of tire. When a green tire including a reinforcing material-rubber composite as a belt (reinforcement layer), where the reinforcing material-rubber composite is obtained using a covering rubber conventionally used for belts, is molded and vulcanized at high temperatures, a portion of the belt (reinforcement layer) where vulcanization progresses quickly (especially the central portion in the tire width direction of the belt) is greatly advanced in vulcanization, passing a proper vulcanization state and becoming over-vulcanized. Then, when it is over-vulcanized, the modulus of the portion where vulcanization progresses quickly decreases, which results in a variation of modulus over the entire belt. When the variation of modulus of the belt is large, the tire performance deteriorates. Therefore, there has been a limit in improving the productivity of the tire by increasing the vulcanization temperature. Further, PTL 2 does not mention the productivity of the tire. It could thus be helpful to provide a tire with a high modulus and excellent productivity. (Solution to Problem) A tire including a reinforcement layer including a reinforcing material and a vulcanized rubber covering the reinforcing material, where the vulcanized rubber is a vulcanized rubber of a rubber composition containing N-cyclohexyl-2-benzothiazolylsulfenamide,the content of N-cyclohexyl-2-benzothiazolylsulfenamide is 0.4 parts by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the rubber component,the reinforcing material contains a metal where a steel cord surface is covered with a ternary plating of copper, zinc, and iron,the reinforcement layer is arranged on the inside of a tread surface in the tire radial direction, anda ratio (a/b) of a modulus (a) at 50 % elongation of the vulcanized rubber covering the reinforcing material in the central portion of the reinforcement layer in the tire width direction, measured by a tensile test at room temperature (25 °C) according to JIS K6251:2017, and a modulus (b) at 50 % elongation of the vulcanized rubber covering the reinforcing material in the end portion of the reinforcement layer in the tire width direction, measured by a tensile test at room temperature (25 °C) according to JIS K6251:2017, is 0.94 or more and 1.06 or less. The tire of the present disclosure is excellent in productivity because the modulus of the vulcanized rubber covering the reinforcing material is uniform in the reinforcement layer and vulcanization can be performed at high temperatures for a short time. (Advantageous Effect) According to the present disclosure, it is possible to provide a tire with a high modulus and excellent productivity. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: FIG. 1 is a cross-sectional view of an embodiment of a tire of the present disclosure. DETAILED DESCRIPTION The following describes the present disclosure in detail based on the embodiments. In the following description, the description of "A to B" indicating a numerical range represents a numerical range including A and B which are end points, and it represents "A or more and B or less" (when A<B), or "A or less and B or more" (when A>B). Further, "part by mass" and "% by mass" have the same meaning as "part by weight" and "% by weight", respectively. <Tire> A tire of the present disclosure includes a reinforcement layer including a reinforcing material and a vulcanized rubber covering the reinforcing material, where the vulcanized rubber is a vulcanized rubber of a rubber composition containing N-cyclohexyl-2-benzothiazolylsulfenamide, the content of N-cyclohexyl-2-benzothiazolylsulfenamide is 0.4 parts by mass or more a