Peroxide is one of the commonly used vulcanizates for rubber products. Peroxide vulcanizates have good heat resistance and low compression set. Peroxide vulcanization is often used in the production of rubber products with high requirements for heat resistance and low compression set using reclaimed butadiene nitrile rubber as the main raw material. Peroxide curing agent can be divided into organic peroxide and inorganic peroxide. When using different types of peroxide for vulcanization of butadiene nitrile reclaimed rubber products, it is necessary to reasonably determine the amount of peroxide, curing agent and curing conditions.
1. Nitrile butadiene reclaimed rubber is vulcanized with organic peroxide
claimed rubber is dicumyl peroxide DCP, which is generally controlled among 1.5-2 phr, and can be increased to 5 phr if necessary. In actual production, the reclaimed nitrile rubber 2ELYY1128 vulcanizate vulcanized with peroxide had good dynamic fatigue properties; Low compression permanent deformation in hot oil and hot air, good aging resistance; Better tensile strength and higher tensile stress; It is not easy to spray frost. It should be noted that the tear resistance of peroxide vulcanizate is poor.
When butadiene nitrile reclaimed rubber products are vulcanized with peroxide, the curing temperature and curing time of peroxide depend on the decomposition rate of peroxide. In order to ensure adequate vulcanization, the vulcanization time is determined to be 5-10 times of the half reduction period of peroxide decomposition (the half reduction period of decomposition is the time required for half decomposition of peroxide). For example, the half-life of peroxide decomposition at 150 ℃ is 1 minute, and the determined curing time should be 5-10 minutes.
2. Nitrile butadiene reclaimed rubber is vulcanized with inorganic peroxide
Inorganic lead peroxide can also be used to vulcanize the reclaimed butadiene acrylonitrile rubber and high acrylonitrile butadiene acrylonitrile rubber when they are used together, and the dosage should be controlled among 5-10 phr. In actual production, about 5 phr of lead peroxide is favorable to the heat resistance of NBR vulcanizate; With the increase of lead peroxide content, the modulus and oil resistance of vulcanizate will be improved.
3. Selection of peroxide curing aids for nitrile reclaimed rubber
In actual production, the cross-linking agent can improve the cross-linking degredive of the reclaimed butadiene acrylonitrile rubber vulcanizate and improve the performance of the vulcanizate. The common crosslinking aids used in the peroxide curing system of butadiene nitrile reclaimed rubber include triallyl cyanurate, quinoxime and other compounds with multifunctional groups, polymers with multifunctional groups or sulfur compounds; When quinone oxime was used as crosslinking agent, the heat resistance of NBR reclaimed vulcanizate was obviously improved.
When using nitrile reclaimed rubber to produce rubber products, you can also use sulfur curing system, resin curing system, quinone oxime curing system, etc. Later, I will continue to discuss relevant issues with you.
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