JP-2026075407-A - Rubber composition for heat-resistant conveyor belts and heat-resistant conveyor belts

Abstract

[Problem] To provide a rubber composition for heat-resistant conveyor belts that is excellent in foaming resistance and heat aging resistance, and a heat-resistant conveyor belt manufactured using the same. [Solution] A rubber composition for heat-resistant conveyor belts, comprising ethylene propylene rubber, ethylene-1-butene copolymer, stearic acid, and a peroxide crosslinking agent, wherein the mass ratio of the ethylene propylene rubber to the ethylene-1-butene copolymer is 10/90 to 60/40, and the mass ratio of the stearic acid to the peroxide crosslinking agent is 0.002 to 0.3. [Selection Diagram] None

Inventors

• 中溝 隆太郎

Assignees

• 横浜ゴム株式会社

Dates

Publication Date

20260508

Application Date

20241022

Claims (6)

1. It contains ethylene propylene rubber, ethylene-1-butene copolymer, stearic acid, and a peroxide crosslinking agent. The mass ratio of the ethylene propylene rubber to the ethylene-1-butene copolymer is 10/90 to 60/40. A rubber composition for heat-resistant conveyor belts, wherein the ratio of stearic acid to the peroxide crosslinking agent is 0.002 to 0.3 by mass.
2. The heat-resistant conveyor belt rubber composition according to claim 1, wherein the ethylene content of the ethylene propylene rubber is 49 to 65% by mass.
3. The heat-resistant conveyor belt rubber composition according to claim 1, wherein the melting point of the ethylene-1-butene copolymer is 34 to 76°C.
4. The heat-resistant conveyor belt rubber composition according to claim 1, wherein the stearic acid content is 0.01 to 0.50 parts by mass per 100 parts by mass of the total of the ethylene propylene rubber and the ethylene-1-butene copolymer.
5. A heat-resistant conveyor belt rubber composition according to claim 1, used for belt covers.
6. A heat-resistant conveyor belt manufactured using the heat-resistant rubber composition for conveyor belts described in any one of claims 1 to 5.

Description

This invention relates to a rubber composition for heat-resistant conveyor belts and a heat-resistant conveyor belt. Conventionally, rubber compositions for heat-resistant conveyor belts are known that contain ethylene propylene rubber, ethylene-1-butene copolymer, stearic acid, and a peroxide crosslinking agent (for example, Patent Document 1). Japanese Patent Publication No. 2011-178917 This is a cross-sectional view of one embodiment of the heat-resistant conveyor belt of the present invention.This is a cross-sectional view of another embodiment of the heat-resistant conveyor belt of the present invention. The heat-resistant conveyor belt and the like of the present invention will be described below. In this specification, numerical ranges expressed using "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits, respectively. Furthermore, each component may be used alone or in combination of two or more. When two or more components are used in combination, the "content" of each component refers to the total content unless otherwise specified. Furthermore, with respect to rubber compositions for heat-resistant conveyor belts, the heat aging resistance after vulcanization is also simply referred to as "heat aging resistance." [1] Rubber composition for heat-resistant conveyor belts The rubber composition for heat-resistant conveyor belts of the present invention (hereinafter also simply referred to as "the composition of the present invention") is It contains ethylene propylene rubber (hereinafter also referred to as "EPM"), ethylene-1-butene copolymer (hereinafter also referred to as "EBM"), stearic acid, and a peroxide crosslinking agent (hereinafter simply referred to as "peroxide"), The mass ratio of the above ethylene propylene rubber to the above ethylene-1-butene copolymer is 10/90 to 60/40. This is a rubber composition for heat-resistant conveyor belts, wherein the ratio of the stearic acid to the peroxide crosslinking agent is 0.002 to 0.3 by mass. The composition of the present invention is believed to solve the aforementioned problems due to its configuration. Although the reason is not clear, it is presumed that because the ratio of stearic acid to peroxide in the composition of the present invention is limited to a specific range, the decomposition of peroxide by stearic acid is suppressed while maintaining the promotion of crosslinking by stearic acid. The following describes each component contained in the composition of the present invention. [Ethylene propylene rubber] Ethylene propylene rubber (EPM) is a copolymer of ethylene and propylene. [Ethylene content] The ethylene content of EPM is not particularly limited, but for superior effects of the present invention, it is preferably 10 to 90% by mass, more preferably 30 to 70% by mass, and even more preferably 49 to 65% by mass. Note that the ethylene content of EPM refers to the percentage (by mass) of units derived from ethylene in the EPM. [Ethylene-1-butene copolymer] Ethylene-1-butene copolymer (EBM) is a copolymer of ethylene and 1-butene. [Ethylene content] The ethylene content of EBM is not particularly limited, but 60 to 90% by mass is preferred, and 65 to 85% by mass is more preferred, for better effects of the present invention. Note that the ethylene content of EBM refers to the percentage (by mass) of units derived from ethylene in the EBM. [Melting point] The melting point of EBM is not particularly limited, but it is preferably 34 to 76°C for better performance of the present invention. Note that the above melting point is the melting point at 1 atmosphere. One way to change the melting point is to change the ethylene content. [EPM/EBM] The mass ratio of EPM to EBM (EPM/EBM) is between 10/90 and 60/40. In other words, the proportion of EPM to the total of EPM and EBM (hereinafter also referred to as "EPM/(EPM+EBM)") is between 10 and 60 mass%. [Stearic acid] The composition of the present invention contains stearic acid. [Content] In the composition of the present invention, the stearic acid content is preferably 0.001 to 1.0 parts by mass, more preferably 0.01 to 0.50 parts by mass, and even more preferably 0.10 to 0.30 parts by mass, per 100 parts by mass of the rubber component (particularly the sum of the EPM and EBM mentioned above), for reasons that the effects of the present invention are superior. [Peroxide Crosslinking Agent] The composition of the present invention contains a peroxide crosslinking agent. Peroxide crosslinking agents are peroxides and function as crosslinking agents. The peroxide crosslinking agent is not particularly limited, but it is preferably an organic peroxide for the reason that the effects of the present invention are superior. Specific examples include dicumyl peroxide, di-t-butyl peroxide, 1,3-bis(t-butylperoxyisopropyl)benzene (1,3-bis(t-butyldioxyisopropyl)benzene), 4,4'-di(t-butylperoxy)valericate n-butyl, and 2,5-dimethyl-2,5-bis(t-butylper