EPDM recycled rubber is generally processed from EPDM head rubber, unvulcanized EPDM rubber or waste EPDM sealing strips as raw materials, with excellent high and low temperature resistance, and can be used alone or in combination with EPDM rubber, butyl rubber, and butyl recycled rubber to produce heat-resistant rubber products to reduce raw material costs. In actual production, most heat-resistant EPDM recycled rubber products are vulcanized with peroxide, why is that? What problems should be paid attention to when using peroxide vulcanization for EPDM recycled rubber products?
1. The advantages of peroxide vulcanization of heat-resistant EPDM recycled rubber products
When using EPDM recycled rubber to produce heat-resistant rubber products, the choice of vulcanization system is crucial, different vulcanization systems will form different cross-linking bonds, the larger the cross-linking bond energy, the better the heat resistance of vulcanized rubber. When EPDM recycled rubber is vulcanized with peroxide E5LYY910 the peroxide cracks under the action of heat to form two alkoxy radicals. alkoxy radicals take hydrogen atoms from the polymer chain to form macromolecular radicals; Two adjacent macromolecular radicals coupled to form a -C-C-crosslinked bond. Among the common types of cross-linked bonds, -C-C-cross-linked bonds have the highest bonding energy, and EPDM recycled adhesive vulcanized adhesive has excellent heat resistance.
2. Problems that need to be paid attention to when using peroxide vulcanization of EPDM recycled adhesive
(1) Vulcanization process: When peroxide vulcanized EPDM recycled rubber is used alone, there are problems such as low cross-linking density, low thermal tear strength, and vulcanization reversion.
(2) Mechanical strength: The tensile strength and tear strength of EPDM recycled adhesive vulcanized with peroxide vulcanization are lower than those of ordinary sulfur vulcanization system.
(3) Odor: Peroxide will produce acetophenone at high temperature decomposition, which is not easy to volatilize and has a strong odor; After vulcanization of EPDM recycled rubber with peroxide vulcanization, the by-products of peroxide residue make the finished product have obvious odor.
(4) Storage: Peroxide masterbatch or compound rubber should not be stored for a long time to prevent peroxide failure.
3. Methods to improve the mechanical strength, odor and storage problems of EPDM recycled adhesive vulcanized rubber
(1) When heat-resistant EPDM recycled rubber products are vulcanized with peroxide, a small amount of sulfur (0.1-0.3 parts) or high ethylene EPDM compound can be added in an appropriate amount.
(2) When using peroxide vulcanization for heat-resistant EPDM recycled adhesive, if there are strict requirements for odor, give priority to the use of odorless DCP and pay attention to the problem of frosting; or use secondary vulcanization, heated in a circulating air oven, volatilize some low molecular substances, and reduce odor; If necessary, use an appropriate amount of rubber odor remover to mask or neutralize odors.
4. EPDM recycled rubber produces heat-resistant rubber conveyor belt covering rubber vulcanization formula
EPDM 70 parts, EPDM recycled rubber 30 parts, zinc oxide 4.5 parts, stearic acid 1 part, carbon black N330 40 parts, paraffin oil 4.5 parts, accelerator M 1.8 parts, accelerator TMTD 1.4 parts, sulfur 1.8 parts; Total: 155 copies.
When heat-resistant EPDM rubber products are vulcanized with peroxide, rubber product manufacturers must reasonably control the amount of peroxide, and appropriately adjust the production process parameters, and continue to discuss related issues with you later.
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