The belt core of canvas core heat-resistant conveyor belt is composed of one or more layers of canvas, the canvas is calendered and glued, and there shall be a covering layer outside the belt core layer. In the actual use process, the covering rubber of canvas core heat-resistant conveyor belt requires that the rubber material has excellent heat resistance and is not easy to aging when used at high temperature. It is generally processed with styrene butadiene rubber or EPDM as the main raw material;Reasonable use of EPDM recycled rubber can effectively reduce the cost of raw materials on the premise of ensuring the service performance and service life of heat-resistant conveyor belt covering rubber.
1. Application mode of EPDM reclaimed rubber in covering rubber of canvas core heat-resistant conveyor belt
Theoretically, the covering rubber of canvas core heat-resistant conveyor belt with strict heat resistance requirements is generally processed with EPDM, while the conveyor belt with relatively low heat resistance requirements can use styrene butadiene rubber, neoprene, etc. EPDM reclaimed rubber as 2elyy517 is a low-cost raw material for EPDM raw rubber. It can be used alone or in combination with EPDM to prepare canvas core heat-resistant conveyor belt covering rubber.
In actual production, EPDM reclaimed rubber can also be used with butyl rubber and butyl reclaimed rubber to produce heat-resistant conveyor belt covering rubber; Or mixed with styrene butadiene rubber to further improve the heat resistance of conveyor belt covering rubber.
2. Formulation design of covering rubber for canvas core heat-resistant conveyor belt mixed with EPDM reclaimed rubber
(1) Vulcanization system: when the covering rubber of canvas core heat-resistant conveyor belt is used alone or in combination with EPDM raw rubber, the vulcanizate has better heat aging performance by using low sulfur coordination or peroxide vulcanization system. EPDM reclaimed rubber / styrene butadiene rubber is used to produce heat-resistant conveyor belt covering rubber, which mostly adopts sulfur-free combination to improve the heat resistance of the rubber.
(2) Reinforcement and filling: in the reinforcement and filling system of canvas core conveyor belt covering rubber mixed with EPDM reclaimed rubber, high wear-resistant carbon black and air mixed carbon black are generally used to increase the hardness of rubber and prevent high-temperature cracking of conveyor belt covering rubber during operation; If necessary, a small amount of white carbon black can be used to replace carbon black to meet the physical and mechanical strength requirements of the covering glue and further improve the heat resistance and aging resistance of the finished product. Calcium carbonate, carbon black and white carbon black are often used as fillers.
(3) Softening and plasticizing: when using EPDM reclaimed rubber to produce the covering rubber of canvas core heat-resistant conveyor belt, it is recommended to use softeners with low volatilization under high temperature and high thermal decomposition temperature. Commonly used are paraffin oil, coal tar, solid coumarone, chlorinated paraffin, etc; When in use, several softeners and plasticizers can be used together to improve the viscosity and heat resistance of the covering glue and avoid migration.
EPDM has excellent heat resistance and aging resistance. From the performance point of view, it is an ideal raw material for preparing the covering rubber of canvas core conveyor belt; However, the processing performance of EPDM raw rubber itself is poor, and the molding viscosity at room temperature is poor. The appropriate use of EPDM reclaimed rubber can not only reduce the raw material cost, but also improve the processing performance of rubber. Later Xiaobian will continue to share with you the production technology of canvas core heat-resistant conveyor belt covering glue mixed with recycled rubber.
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