The rubber sealing ring produced by using nitrile rubber has excellent oil resistance and can retain good sealing effect in oil medium for a long time; using nitrile rubber and nitrile reclaimed rubber can produce various cost-effective oil-resistant sealing rings and improve oil-resistant rubber. The market competitiveness of the seals. The design of the nitrile seal ring vulcanization system not only affects the mechanical strength of the product, but also affects the oil resistance of the seal ring. How to design the vulcanization system of the nitrile seal ring in actual production?
When using a nitrile rubber or a reclaimed rubber to produce a rubber seal, the commonly used vulcanizing agents are sulfur, sulfur compounds, peroxides and resins. Different types of vulcanizing agents need to be used with different accelerators, and the amount of each compound in the vulcanization system. Directly affect the comprehensive performance of the nitrile seal. Nitrile rubber seals require high compression set resistance of the rubber compounds used. Therefore, manufacturers of nitrile rubber/recycled rubber seals mostly use low sulfur and sulfur compounds, or use sulfur compounds and peroxides alone. Vulcanizing agent.
1. When sulfur is contained in the vulcanization system of the nitrile seal, the tensile stress and hardness of the vulcanized rubber will increase with the increase of the amount of sulfur, and the heat resistance and oil resistance will be slightly improved; but the sulfur is in the nitrile. The solubility in the compound is low, and the amount of vulcanization needs to be controlled between 1-3.5 parts. The higher the acrylonitrile content, the less sulfur is used in the nitrile rubber or reclaimed rubber formulation.
2. In order to improve the heat resistance and compression set resistance of the nitrile seal ring, the rubber product manufacturers prefer the low sulfur compound, and the sulfur dosage is controlled to be less than 0.5 parts, and the amount of the vulcanization accelerator is increased. The thiuram accelerator can significantly improve the compression set resistance of the rubber compound, and cooperate with the use of sulfenamide accelerators, amine accelerators and anthraquinone accelerators as auxiliary accelerators; sulfur and thiuram accelerators The combination of TMTD, TRA, and TRT can achieve good heat resistance. Sulfur and accelerators are used in different proportions, and the performance of the nitrile seals varies greatly. Among them, the combination of sulfur and accelerator DM is a commonly used vulcanization system. After being used together with the accelerator TS, the nitrile vulcanizate has low compression set and is not easily scorched.
3. Nitrile rubber / reclaimed rubber production of oil-resistant seals When low-sulfur or sulfur-free blending is used, zinc oxide and stearic acid are often used as vulcanization accelerators and active agents. The amount of zinc oxide is controlled in 1-5 parts, generally 5 The zinc oxide is used in combination with 1 part of stearic acid.
The use of nitrile rubber or nitrile reclaimed rubber to produce rubber seals often uses a sulfur-free vulcanization system. The combination of thiuram accelerator and disulfide morpholine is the most common; rational design of nitrile rubber oil-resistant seal vulcanization system, The heat resistance and compression set resistance of the nitrile rubber seal can be further improved. I heard that the sulfur/accelerator TMTD/accelerator CZ in the nitrile seal vulcanization system can be used in a ratio of 0.5/1/1 to obtain better heat resistance. Is this true?
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