In the rubber industry, nitrile rubber has excellent oil resistance, heat resistance and wear resistance, and is widely used in the manufacture of oil seals. Reclaimed rubber is made from waste rubber desulfurization and regeneration, the price is much lower than that of original rubber, and it can be readded to the production of rubber products. When using nitrile rubber as the main raw material to produce rubber oil seals, the appropriate amount of reclaimed rubber and reasonable design of rubber formula can effectively reduce the production cost under the premise of ensuring the performance of oil seals.
1. Problems to be considered in the design of nitrile rubber oil seal formula containing reclaimed rubber.
(1) Consider the use environment of nitrile rubber oil seals, the requirements for oil resistance, heat aging resistance, wear resistance, etc. The hardness is generally controlled at 75±5 to adapt to the friction temperature of the oil seal in operation and use, which is usually 20~30°C higher than the oil temperature, and may be higher under special circumstances. (2) Consider the influence of the addition of reclaimed rubber on the performance of the rubber compound. The addition of reclaimed rubber may affect the hardness, tensile strength, elongation at break and other physical properties of the rubber compound; Reasonable design of the formula and appropriate adjustment of the formula can balance the performance and cost of nitrile rubber oil seal.
2. Nitrile rubber/reclaimed rubber is used to produce oil seal vulcanization formula
90 parts of nitrile rubber, 10 parts of reclaimed rubber, 9 parts of zinc oxide, 1.8 parts of stearic acid, 1 part of antioxidant D, 15 parts of carbon black N774, 40 parts of mixed carbon black, 3.5 parts of asbestos powder, 3.5 parts of graphite powder, 13 parts of light calcium, 7 parts of magnesium carbonate, 1.8 parts of pine tar, 3.6 parts of glycerin, 0.6 parts of accelerator D, 0.4 parts of accelerator DM, 1.2 parts of accelerator M, 2.8 parts of sulfur; Total 204.2 copies.
3. Nitrile rubber/reclaimed rubber combined with the production of oil seal formula design points
When using nitrile rubber/reclaimed rubber and rubber to produce ordinary oil seals, nitrile rubber can be used to improve heat aging resistance by using vulcanization systems such as low sulfur and high promotion, peroxide, composite system, cadmium and magnesium. The use of reinforcing carbon black E4LYY530, or combining reinforcing carbon black with other carbon blacks, can improve the oil resistance, aging resistance, physical and mechanical properties, and compression set resistance of the compound. Antioxidants can improve the aging resistance of oil seals; Plasticizers improve the processing flow of compounds while imparting flexibility and elasticity.
When nitrile rubber oil seals are mixed with reclaimed rubber to reduce costs, formula design is crucial; Reasonably controlling the combined use ratio of nitrile rubber and reclaimed rubber, and appropriately adjusting the variety and dosage of vulcanization system, reinforcing system compounding agent and other operating additives in the formula, can significantly reduce production costs and enhance the market competitiveness of products on the basis of ensuring the core properties of oil seals such as oil resistance, heat resistance and wear resistance.
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