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JP-7856471-B2 - Rubber composition, outsole, method for manufacturing the rubber composition, and method for manufacturing a crosslinked rubber sheet

JP7856471B2JP 7856471 B2JP7856471 B2JP 7856471B2JP-7856471-B2

Inventors

  • 塩月 康平
  • 山崎 英樹
  • 羽山 剛司

Assignees

  • 日本エラストマー株式会社

Dates

Publication Date
20260511
Application Date
20220411

Claims (11)

  1. (A): The mass ratio of styrene block amount / bound styrene amount is 0.02 to 0.23. The amount of 1,2-vinyl bonds in the butadiene portion is 10 to 60% by mass. The amount of bound styrene is 35 to 55% by mass. And, Mooney viscosity is in the range of 80 to 110. 5 to 50% by mass of styrene-butadiene copolymer rubber, (B): 50 to 95% by mass of diene rubber, which is at least one selected from the group consisting of natural rubber, diene-based synthetic rubber, and block copolymers of aromatic vinyl compounds and conjugated diene compounds, and which has a Mooney viscosity of 20 or more and less than 80. The rubber component contained therein, With respect to 100 parts by mass of the rubber component consisting of (A) styrene-butadiene copolymer rubber and (B) diene rubber, (C): Filler 10 to 50 parts by mass, (D): A rubber composition containing 0.01 to 1 part by mass of a fatty acid and/or fatty acid derivative having an alkyl or alkenyl group having 8 to 30 carbon atoms .
  2. With respect to 100 parts by mass of the rubber component consisting of (A) styrene-butadiene copolymer rubber and (B) diene-based rubber, (E): Further containing 0 to 5 parts by mass of liquid diene rubber, The rubber composition according to claim 1.
  3. The amount of styrene blocks in the (A) styrene-butadiene copolymer rubber is 0.70 to 12% by mass. The rubber composition according to claim 1 or 2.
  4. The refractive index of the (A) styrene-butadiene copolymer rubber is 1.530 to 1.570. The refractive index of the diene rubber (B) is 1.450 to 1.530, and the refractive index of the filler (C) is 1.370 to 1.500. The rubber composition according to claim 1 or 2.
  5. The amount of bound styrene in the styrene-butadiene copolymer rubber (A) is 40 to 50% by mass. The rubber composition according to claim 1 or 2.
  6. The (C) filler is at least one selected from the group consisting of silica, magnesium carbonate, carbon black, and magnesium hydroxide. The rubber composition according to claim 1 or 2.
  7. The above (E) liquid diene rubber, Butadiene, and/or an oligomer of styrene-butadiene or acrylonitrile-butadiene, The rubber composition according to claim 2.
  8. The haze level is 10-40%. The rubber composition according to claim 1 or 2.
  9. An outsole comprising the rubber composition described in claim 1 or 2.
  10. A bale containing (A) 98 to 99.98% by mass of styrene-butadiene copolymer rubber and (D) 0.02 to 2% by mass of fatty acids and/or fatty acid derivatives having an alkyl or alkenyl group having 8 to 30 carbon atoms , (B) A diene rubber selected from the group consisting of natural rubber, diene-based synthetic rubber, and block copolymers of aromatic vinyl compounds and conjugated diene compounds, wherein the Mooney viscosity is 20 or more and less than 80, The above (A) and the above (B) are such that the mass ratio of (A)/(B) is 5/95 to 50/50, and The process involves kneading 100 parts by mass of the rubber component consisting of (A) and (B) with 10 to 50 parts by mass of the filler (C), The (A) styrene-butadiene copolymer rubber has a ratio of styrene block amount to bound styrene amount of 0.02 to 0.23, a 1,2-vinyl bond amount of the butadiene portion of 10 to 60% by mass, a bound styrene amount of 35 to 55% by mass, and a Mooney viscosity of 80 to 110. A method for producing a rubber composition.
  11. A bale containing (A) 98 to 99.98% by mass of styrene-butadiene copolymer rubber and (D) 0.02 to 2% by mass of fatty acids and/or fatty acid derivatives having an alkyl or alkenyl group having 8 to 30 carbon atoms , (B) A diene rubber selected from the group consisting of natural rubber, diene-based synthetic rubber, and block copolymers of aromatic vinyl compounds and conjugated diene compounds, wherein the Mooney viscosity is 20 or more and less than 80, The above (A) and the above (B) are such that the mass ratio of (A)/(B) is 5/95 to 50/50, and A step of kneading 100 parts by mass of the rubber component consisting of (A) and (B) with 10 to 50% by mass of (C) filler to obtain a kneaded product, The process involves mixing (G) a crosslinking agent into the aforementioned kneaded mixture and then pressurizing and/or heating it, It has, The (A) styrene-butadiene copolymer rubber has a ratio of styrene block amount to bound styrene amount of 0.02 to 0.23, a 1,2-vinyl bond amount of the butadiene portion of 10 to 60% by mass, a bound styrene amount of 35 to 55% by mass, and a Mooney viscosity of 80 to 110. A method for manufacturing cross-linked rubber sheets.

Description

This invention relates to a rubber composition, an outsole, a method for producing a rubber composition, and a method for producing a crosslinked rubber sheet. Footwear outsoles require not only functional properties such as abrasion resistance, but also fashionability, such as transparency to allow the design and/or color of the midsole (the middle layer of the footwear) to show through. Various rubber compositions have been developed with the aim of manufacturing such footwear outsoles. Patent Document 1 discloses a rubber composition with excellent transparency, comprising a two-component rubber polymer having a predetermined refractive index difference and wet silica. Furthermore, Patent Document 2 discloses a rubber composition that combines a low-CIS isoprene rubber component (hereinafter also referred to as "IR") that is substantially free of silica with other rubber components. Furthermore, Patent Documents 3 and 4 disclose rubber compositions for footwear soles using block styrene-butadiene rubber (hereinafter also referred to as "SBR") and/or random SBR. Japanese Patent Publication No. 2005-2225Japanese Patent Publication No. 2017-66423International Publication No. 2018/193555Japanese Unexamined Patent Publication No. 63-11102 The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "these embodiments"). These embodiments are illustrative examples for explaining the present invention, and the present invention is not limited to these embodiments. The present invention can be appropriately modified and implemented within the scope of its gist. [Rubber composition] The rubber composition of this embodiment is (A): The mass ratio of styrene block amount / bound styrene amount is 0.02 to 0.23. The amount of 1,2-bonds in the butadiene portion is 10 to 60% by mass. The amount of bound styrene is 35 to 55% by mass. It contains 5 to 50% by mass of styrene-butadiene copolymer rubber, with a Mooney viscosity in the range of 80 to 110, (B): 50 to 95% by mass of diene rubber, which is at least one selected from the group consisting of natural rubber, diene-based synthetic rubber, and block copolymers of aromatic vinyl compounds and conjugated diene compounds, and which has a Mooney viscosity of 20 or more and less than 80. The rubber component contained therein, With respect to 100 parts by mass of the rubber component consisting of (A) styrene-butadiene copolymer rubber and (B) diene rubber, (C): 10 to 50 parts by mass of filler, (D): Contains 0.01 to 1 part by mass of fatty acids and/or fatty acid derivatives. According to this embodiment, it is possible to provide a rubber composition that improves the abrasion resistance and strength of the crosslinked rubber composition without impairing the processability of the rubber composition. ((A) Styrene-butadiene copolymer rubber) The rubber composition of this embodiment contains (A) styrene-butadiene copolymer rubber (which may be referred to as component (A) in this specification). Component (A) has a mass ratio of styrene block amount/bonded styrene amount of 0.02 to 0.23, a 1,2-bonding amount of the butadiene portion of 10 to 60% by mass, a bonded styrene amount of 35 to 55% by mass, and a Mooney viscosity at 100°C measured in accordance with JIS K6300-1 in the range of 80 to 110. The present inventors have found that a rubber composition containing (A) styrene-butadiene copolymer rubber in a predetermined proportion exhibits excellent abrasion resistance and superior processability (ease of mixing) when processed into molded articles such as outsoles. In this specification, styrene-butadiene copolymer rubber refers to a copolymer of styrene monomer and butadiene monomer. Hereinafter, in styrene-butadiene copolymer rubber, the portion derived from styrene monomer is referred to as the styrene portion, and the portion derived from butadiene monomer is referred to as the butadiene portion. <Amount of bound styrene> (A) The styrene-butadiene copolymer rubber has a bound styrene content of 35 to 55% by mass. This yields a rubber composition with excellent mechanical properties such as tensile strength and tear strength. From a similar viewpoint, the bound styrene content of component (A) is preferably 38 to 53% by mass, more preferably 40 to 50% by mass. When the amount of bound styrene is 35 to 55% by mass, the refractive index of (A) styrene-butadiene copolymer rubber is approximately 1.544 to 1.561. In this specification, "bound styrene content" means the content (mass%) of styrene monomer units in (A) styrene-butadiene copolymer rubber. That is, in (A) styrene-butadiene copolymer rubber, the bound styrene content means the mass ratio of the styrene portion to the total mass of the styrene portion and the butadiene portion, and therefore represents the total amount of styrene monomer units constituting the styrene blocks contained in component (A), and, if component (A) has random blocks, the total amou