Heat-resistant rubber sheet can maintain good physical properties and elasticity at high temperatures, and is widely used in various high-temperature environments such as chemical industry, metallurgy, electric power, etc., playing the role of sealing, shock absorption, and anti-slip. Heat-resistant rubber sheets are generally made of rubber with excellent heat resistance as the main raw material, such as butyl rubber, EPDM rubber, fluorine rubber, etc. As a renewable resource in the rubber industry that can reduce the cost of products, can reclaimed rubber be used to produce heat-resistant rubber sheets? And how to improve the heat resistance of recycled rubber sheets? How to design a vulcanization formula for heat-resistant recycled rubber sheets?
1. Selection skills of reclaimed rubber for heat-resistant rubber sheets
When using reclaimed rubber to produce heat-resistant rubber sheets, the heat resistance of reclaimed rubber is a top priority. In actual production, the heat resistance of reclaimed rubber is closely related to its variety. Low-unsaturation rubbers such as butyl rubber and EPDM rubber exhibit excellent heat resistance due to their low double bond content in their molecular structure. Butyl reclaimed rubber and EPDM reclaimed rubber retain the basic performance characteristics of butyl rubber and ethylene propylene reclaimed rubber, with good heat resistance, and can be used in the production of heat-resistant rubber sheets.
2. Vulcanization formula design for heat-resistant rubber plate for reclaimed rubber production
When using reclaimed rubber to produce low-cost heat-resistant rubber sheets, the heat resistance of the finished rubber sheets is closely related to the vulcanization system, filler system, softening system and anti-aging system.
(1) Design of vulcanization system for heat-resistant recycled rubber sheet
The vulcanization system has a decisive influence on the heat resistance of the vulcanized rubber, which is related to the thermal stability of the cross-linked bonds generated in the rubber. In general, the reclaimed rubber chooses thiuram and other sulfur carriers or peroxide vulcanization systems, which can give the reclaimed rubber 2SLYY1227 vulcanized rubber higher thermal stability than the traditional sulfur vulcanization. In the production of heat-resistant rubber sheets, nitrile recycled rubber, EPDM recycled rubber and other recycled rubber are vulcanized with peroxide, and butyl reclaimed rubber is vulcanized with resin, and the heat resistance of reclaimed rubber vulcanized rubber is better than that of sulfur vulcanized rubber.
(2) Design of heat-resistant recycled rubber sheet filler system
When reclaimed rubber is used to produce heat-resistant rubber sheets, inorganic fillers have better heat resistance than carbon black, and an appropriate amount of inorganic fillers such as silica, zinc oxide, magnesium oxide, silicate, etc., can improve the heat resistance of reclaimed rubber vulcanized rubber.
(3) Design of softening system for heat-resistant recycled rubber sheet
The softener has a great influence on the heat resistance of the reclaimed rubber, and the softener with low molecular weight is easy to migrate or volatilize at high temperatures, resulting in an increase in the hardness of the vulcanized rubber, a decrease in elongation, and a decrease in elasticity. Therefore, when using reclaimed rubber to produce heat-resistant rubber sheets, it is recommended to choose polyester plasticizers or reactive softeners with large molecular weight and high boiling point to reduce migration and volatilization at high temperatures and maintain the flexibility and elasticity of rubber sheets.
(4) Design of heat-resistant recycled rubber sheet anti-aging system
When producing heat-resistant rubber sheets, select high-efficiency heat-resistant antioxidants and increase the dosage appropriately, and use two or more antioxidants together, which can effectively improve the heat resistance of recycled rubber sheets.
When using reclaimed rubber to reduce the production cost of heat-resistant rubber sheets, rubber product manufacturers not only need to choose the right reclaimed rubber products, reasonably design the vulcanization formula of reclaimed rubber, but also need to properly adjust the production process parameters, especially the mixing process and vulcanization molding.
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