The main function of the rubber brake cup is to transfer the calendering of the sealing box, so the elasticity, heat resistance, wear resistance and compression set of the rubber are required to be high; the brake for long-term working in the mineral oil type brake fluid The cup is generally made of nitrile rubber as the main material; in actual production, in order to ensure the good performance of the brake cup, the rubber product manufacturer needs to rationally design the nitrile rubber/recycled rubber brake cup formula, and carefully determine the rubber compound and match. The type and amount of the agent.
1. The nitrile-made cup needs to choose a compound with low acrylonitrile content.
It is well known that the biggest characteristic of nitrile rubber and nitrile reclaimed rubber is that it has excellent oil resistance. The oil resistance of nitrile rubber increases with the increase of acrylonitrile content. However, the nitrile brake cup needs the rubber compound used. The lower brittle temperature, while the brittleness temperature of nitrile rubber and nitrile reclaimed rubber increases with the increase of acrylonitrile content. Therefore, nitrile brake cup needs to choose low acrylonitrile content nitrile rubber and nitrile regeneration. gum.
2. Select peroxide curing system or low sulfur compounding system
The nitrile brake cup has been in the "brake" state for a long time. Frequent friction and heat generation will shorten the life of the cup and lose the sealing effect. To ensure the good heat resistance, wear resistance and compression set of the nitrile brake cup. The peroxide vulcanization system can give the rubber material better heat resistance and low compression set; for the nitrile rubber/recycled rubber brake cup with high mechanical strength, try the low sulfur compounding system. Or use sulfur and peroxide together to coordinate the relationship between physical and mechanical strength and heat resistance of nitrile rubber.
3. The amount of carbon black should not be too much
In actual production, the mechanical properties of rubber products will be significantly improved with the increase of the amount of carbon black, but the excessive use of carbon black will lead to the elasticity, viscous properties, physical and mechanical properties of the rubber compound, and high elasticity requirements. For the brake cup, it is best to avoid the use of super-abrasive carbon black, high wear-resistant carbon black and other varieties with strong reinforcing effect. Select semi-reinforcing carbon black and appropriate filler to use carbon in the nitrile reclaimed rubber. The black content is calculated and the amount of carbon black is controlled to be less than 30 parts to obtain a finished nitrile brake cup product with better comprehensive performance.
4. Try to avoid using softeners
Softener can improve the fluidity and plasticity of rubber compound in the production process of rubber products, but in the formula of nitrile brake cup, to ensure good dimensional stability, wear resistance and low compression set, try to avoid using Softeners are used to reduce the amount of softener.
Reasonable design of the nitrile brake cup formula ensures that the brake cup working in the mineral oil type brake fluid can quickly transfer pressure while maintaining a good sealing effect; the nitrile reclaimed rubber is reduced as a nitrile brake rubber compound. The ideal raw material cost, not only need to pay attention to the acrylonitrile content, but also pay attention to the fineness, strength, rubber content and other physical properties of the nitrile reclaimed rubber, high-fineness, high gel content of nitrile reclaimed rubber The quality and cost of a nitrile brake cup is most advantageous.