Nitrile rubber is made by polymerizing butadiene and acrylonitrile, and can be used to produce various oil-resistant and wear-resistant rubber products; nitrile reclaimed rubber can replace nitrile rubber to reduce raw material costs. When nitrile rubber or nitrile reclaimed rubber is used to produce rubber products, the sulfur-vulcanized nitrile rubber has high tensile strength, good wear resistance, and excellent fatigue resistance, which can meet the needs of most nitrile rubber products. When sulfur vulcanization is selected for nitrile rubber, sulfur directly affects the performance of NBR products. How should the amount of sulfur in nitrile rubber products be calculated?
1. The content of acrylonitrile/butadiene affects the amount of nitrile sulfur
The higher the acrylonitrile content in nitrile rubber and the relatively lower butadiene content, the amount of sulfur should be appropriately reduced. This is because the higher the content of acrylonitrile, the lower the content of butadiene, and the lower the degree of unsaturation of the nitrile rubber. Therefore, the amount of sulfur in the formulation of nitrile rubber products should be appropriately reduced. For example, butyronitrile-26 has high acrylonitrile content, and the amount of sulfur should be controlled at 1.5-1.75 parts; butyronitrile-18 because the content of butadiene is higher than butyronitrile-26 and the degree of unsaturation is greater than butyronitrile-26, so the amount of sulfur can be increased To 1.75-2 servings.
2. Nitrile rubber performance requirements affect the amount of nitrile sulfur
The physical properties of nitrile rubber compounds with different amounts of sulfur vary greatly after vulcanization. Generally, the higher the amount of sulfur, the greater the hardness of the vulcanized rubber. The heat resistance, elongation at break and tear strength have decreased. Different varieties of nitrile rubber products have different performance requirements for rubber compounds, and rubber product manufacturers need to adjust the amount of sulfur according to actual index requirements. For nitrile rubber products that require high heat resistance and compression permanent deformation resistance, low-sulfur compound can be selected to control the amount of sulfur in 0.1-0.5 parts; the amount of accelerator in the low-sulfur compound is appropriately increased to improve the vulcanization efficiency of nitrile rubber.
When using nitrile rubber or nitrile reclaimed rubber to prepare hard rubber, the amount of sulfur is very large, generally between 10-25 parts.
3. The amount of recycled rubber affects the amount of sulfur in nitrile rubber products
In order to reduce the production cost of nitrile rubber products, appropriate amount of reclaimed rubber can be used in the formulation, of which nitrile reclaimed rubber can directly replace nitrile rubber. When using reclaimed rubber to reduce the production cost of nitrile rubber 2LLYY630 products, rubber product manufacturers need to replace the raw rubber with equal amounts of rubber hydrocarbon content and vulcanized rubber performance in reclaimed rubber. Other ingredients can be regarded as fillers and softeners in the formulation.
In actual production, the addition of reclaimed rubber will disperse the "density" of sulfur in nitrile rubber, so when using sulfur vulcanization directly in the formula of pure nitrile rubber products, the amount of sulfur should be appropriately increased, and the active agent in the formula should be appropriately reduced. , The amount of fillers, softeners, antioxidants.
Theoretically, because the unsaturation of nitrile rubber is lower than that of natural rubber, the amount of sulfur in the formula of nitrile rubber products is generally lower than that of natural rubber products. The vulcanization speed of nitrile rubber is accelerated by appropriately increasing the amount of accelerator. In actual production, nitrile rubber with different acrylonitrile content needs to be combined with different amounts of sulfur vulcanization. The amount of sulfur should be adjusted according to the requirements of physical properties of nitrile rubber products. The amount of sulfur in nitrile rubber products containing recycled rubber should be adjusted. According to the change of the amount of reclaimed rubber.