EPDM rubber is made by copolymerizing ethylene, propylene and a small amount of non-conjugated diene. The main chain is a chemically stable saturated hydrocarbon, which is resistant to aging, weather, chemical corrosion and electrical insulation. However, in the actual use process, the vulcanization speed of EPDM rubber is slow, and it is difficult to use it with other unsaturated rubbers, which greatly limits the application field of EPDM rubber. How can rubber product manufacturers overcome these difficulties?
3. How to solve the problem of slow vulcanization of EPDM rubber
EPDM rubber can be vulcanized with various vulcanization systems such as sulfur, peroxide, quinone oxime or resin. The physical and mechanical properties of the rubber after vulcanization of different vulcanization systems are different. In actual production, the vulcanization speed of the sulfur-accelerator system is relatively fast, and the physical and mechanical properties of the vulcanizate are good, and the application in EPDM rubber is more common. EPDM peroxide vulcanizate has good heat resistance and low compression set, but the vulcanization speed is slow and the vulcanizate may have odor. It is used in rubber products such as door and window seals that have strict requirements on heat resistance and compression deformation. more.
(1) Select the appropriate accelerator and increase the dosage: To increase the vulcanization speed of EPDM rubber, two or more accelerators can be used in the sulfur-accelerator system; auxiliary accelerators can be used when necessary, such as sulfenamide When the accelerator is used as the main accelerator, auxiliary accelerators such as TMTD, TMTM and TETD can be used to effectively improve the vulcanization speed. If the amount of accelerator in the EPDM compound is high and the amount of stearic acid is sufficient, the purpose of increasing the vulcanization speed can also be achieved by increasing the amount of zinc oxide.
(2) Methods to increase the speed of peroxide vulcanization: When EPDM rubber or EPDM reclaimed rubber products are cured by peroxide, a high-performance peroxide formula can be used to speed up the vulcanization speed of the rubber compound. Larger DCP can make the compound cure faster than BBPIB, and peroxyketal peroxide cures faster than dialkyl peroxide; if necessary, peroxide and sulfur can be used in combination.
(3) Properly increase the vulcanization temperature and increase the vulcanization speed.
4. How to solve the problems of poor oil resistance, flame retardancy and air tightness of EPDM rubber
EPDM does not have resistance to oil, so it cannot be used alone in products that are resistant to mineral oils and hydrocarbon solvents; it cannot be used alone in the production of rubber inner tubes such as rubber inner tubes 2ELYY413 that require strict air tightness. In actual production, EPDM rubber can be used in combination with neoprene, nitrile rubber, butyl rubber, and chlorosulfonated polyethylene, and the vulcanizate has good overall performance. For example, adding an appropriate amount of butyl rubber to EPDM rubber can improve the air tightness of the rubber compound while alleviating the problem of aging, hardening and brittleness of the EPDM rubber and prolonging the service life.
When using EPDM rubber to produce flame retardant rubber products, it is necessary to appropriately increase the amount of flame retardant fillers. However, due to the high cost and flame retardant rubber, it is not recommended to use EPDM raw rubber.
In actual production, EPDM rubber can also be used with natural rubber, styrene-butadiene rubber, isoprene rubber, butadiene rubber and other general-purpose rubbers, and can be used with EPDM reclaimed rubber, butyl reclaimed rubber, nitrile reclaimed rubber, etc. Combined use of reclaimed rubber can improve the overall performance of EPDM vulcanizates while further reducing the cost of raw materials, improving the effective efficiency, and reducing the power consumption in the production process. The editor will continue to discuss related issues with you later.
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