Hardness is an important parameter to measure the rubber material index. Many EPDM rubber products often increase the hardness of rubber compound through carbon black, white carbon black, resin, high styrene and other raw materials in the production process to meet the demand of rubber products; However, in the actual application process, the hardness of the rubber is not as high as possible, especially for some molded rubber products with special purposes. So what is the design of the low-hardness EPDM rubber product formula, which materials will be used? Xiaobian today shares with you two low-hardness EPDM rubber formulations 1JLYY827.
Low hardness EPDM rubber reference formula 1:
200 parts of EPDM rubber, 4 parts of zinc oxide, 1 part of stearic acid, 35 parts of high wear-resistant carbon black, 60 parts of semi-reinforcing carbon black, 135 parts of paraffin oil, 3 parts of accelerator BZ, accelerator CZ 2 Parts, 1.6 parts of other accelerators, 1.6 parts of sulfur; total: 443.2 parts.
Low hardness EPDM rubber reference formula 2:
175 parts of EPDM rubber, 5 parts of zinc oxide, 1 part of stearic acid, 50 parts of semi-reinforcing carbon black, 40 parts of light calcium, 80 parts of paraffin oil, 2 parts of alkyl phenolic resin, and 1 part of accelerator M. Promoter CZ 1.5 parts, accelerator TMTD 0.7 parts, 1 other accelerator, sulfur 0.5 parts; a total of 357.7 parts.
When EPDM rubber is used to produce low-hardness rubber products, the hardness of the rubber compound is adjusted mainly by adjusting the type and amount of reinforcing agent and softening plasticizer in the formulation. The paraffin oil in Formulation II is significantly less than the paraffin oil in Formulation 1. This is because the high abrasion resistant carbon black, semi-reinforcing carbon black and light calcium have different effects on the hardness of the rubber. One high wear-resistant carbon black can be used. Increase the hardness of 5/2, 1 part of semi-reinforcing carbon black can increase the hardness value by 1/3, one part of calcium carbonate can only increase the hardness value by 1/6, so formula 1 needs more rubber to use paraffin oil to offset the reinforcement. The reinforcing effect of the agent.
In the production process of EPDM rubber products, the more sulfur is used in theory, the greater the crosslink density of rubber compound, the higher the hardness of rubber products produced. Therefore, when designing low hardness EPDM rubber products, the other indicators meet the premise. The amount of sulfur should be minimized.
The market price of ethylene propylene diene monomer copolymerized with ethylene, propylene and a small amount of non-conjugated diene is high. Therefore, many rubber product manufacturers will choose to mix the appropriate amount of EPDM reclaimed rubber in the raw material; Ethylene-propylene reclaimed rubber retains the basic performance characteristics of EPDM rubber, but its molecular structure and various indexes are different from the original rubber. All or part of the EPDM rubber in the above formula is replaced by EPDM rubber. When making sure to adjust the type and amount of each compounding agent in the formula.
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