The fluidity of rubber is an important process parameter for measuring the operation performance of rubber compound. When using nitrile rubber/recycled rubber to produce oil-resistant sealing products, the fluidity is not good. If local scorch will cause defects in molded oil-resistant sealing products, it will directly affect the injection. The normal production of oil-resistant products such as oil seals, therefore generally choose a nitrile rubber with good fluidity to produce oil-resistant sealed products. In the actual production process, the hardness of the nitrile rubber/recycled rubber, the Mooney viscosity, the processing technology, the mastication temperature, etc. all affect the fluidity of the rubber compound. Generally, the hardness is higher and the Mooney viscosity is higher. The worse the liquidity, the rubber product manufacturers can consider from these aspects, take certain measures to improve the fluidity of the rubber used in the nitrile sealing products, to improve the production process of the nitrile sealing products, and to ensure the normal production and sales of the products.
1. Adjust the formula of nitrile oil resistant sealing products.
Nitrile rubber/recycled rubber has soft nitrile and hard nitrile. The nitrile rubber with a Shore hardness of 75 degrees or less has good fluidity, which can ensure the normal production of nitrile sealing products and high hardness of nitrile. Rubber/recycled rubber is too poor in fluidity; Mooney viscosity is an important indicator reflecting the good processing performance of rubber, high molecular weight and wide distribution range. The viscosity of rubber compound is difficult to flow, and the lower the Mooney viscosity, the better the fluidity of the rubber. Therefore, when using nitrile rubber/recycled rubber to produce oil-resistant sealing products, rubber manufacturers can reduce the amount of reinforcing filler or directly use soft fillers such as soft carbon black, appropriately increase the amount of plasticizer and rubber oil, and increase the nitrile. The distance between the rubber molecular chains reduces the intermolecular force and improves the flowability of the nitrile rubber/recycled rubber.
2. Improve the nitrile rubber/recycled rubber compounding process.
Studies have shown that at a certain shear rate, increasing the shear rate can greatly reduce the viscosity of the rubber compound. Increasing the speed of the rubber mixing machine is a good way to reduce the viscosity of the rubber compound and improve the fluidity of the nitrile rubber/recycled rubber. Extrusion type The nitrile sealing product can increase the extrusion speed of the extruder, and the injection type rubber product can increase the injection pressure; the nitrile rubber/recycled rubber is masticated according to the specific requirements of the sealing product and the mixing process requirements, and the degree of plasticization is determined to ensure uniformity of the compounding agent. Dispersed in the nitrile rubber compound to improve the fluidity of the rubber compound and improve the production process and use effect of the nitrile sealing product.
3. Use processing aids.
Peptizer is an ideal processing aid to improve the plasticity and mastication efficiency of rubber compound. It can accelerate the chain breakage of rubber molecular chain, reduce the viscosity of rubber compound, improve the fluidity of nitrile rubber/recycled rubber, dibenzamide disulfide, Pentachlorothiophenol, zinc salt, accelerator D, accelerator M, and accelerator DM can all be used as peptizers; in the process of mastication of nitrile rubber/recycled rubber, the dispersing of compounding agent and the scorching of rubber are affecting the rubber compound. An important factor of “flow”, the higher the dispersion of the compounding agent in the rubber compound, the better the fluidity of the rubber compound, and a small amount of dispersing agent, internal lubricant, surfactant, and structure control agent can be added to the nitrile sealing product formulation. Or anti-scorching agent, improve the flowability of nitrile rubber compound, and improve the production efficiency of nitrile oil-resistant sealing products.
Nitrile rubber/recycled rubber is a cost-effective raw material for producing oil-resistant sealing products. The plasticity and fluidity of nitrile reclaimed rubber products are higher than that of nitrile-based rubber, and the price is lower than that of original rubber. Therefore, rubber products manufacturers can pass the indicators. Under the premise, the appropriate addition ratio of the nitrile reclaimed rubber in the nitrile sealing product is increased, the production cost of the nitrile sealing product is lowered, and the processing technology is improved.