Constant elongation stress and hardness are important indicators of the stiffness of rubber materials. They are the force required to produce a certain amount of vulcanizate. It is related to the large tensile deformation. The two have a good correlation.
    The larger the molecular weight of the rubber, the greater the effective cross-linking elongation stress. In order to obtain a predetermined elongation stress, the crosslinking density can be appropriately increased for a rubber having a small molecular weight. Structural factors that can increase intermolecular forces. Can improve the resistance of the vulcanized rubber net deformation resistance. Such as CR / NBR / PU / NR, etc. have higher set stress.
    The influence of fixed elongation stress and crosslinking density is great. Regardless of whether it is pure rubber or reinforced vulcanizate, as the crosslinking density increases, the elongation stress and hardness also increase linearly. It is usually achieved by adjusting the varieties of vulcanizing agent, accelerator, co-vulcanizing agent, and active agent. The promotion of sulfur content has a more significant effect on increasing the elongation stress. Polysulfide is beneficial to increase the elongation stress. The filler can improve the product's elongation stress and hardness. The higher the reinforcement performance and the higher the hardness, the higher the elongation stress. With increasing hardness, the increase in filling increases with increasing hardness. On the contrary, the increase of the softener reduces the hardness and the elongation stress. In addition to increasing the reinforcing agent, there is also a combination of alkyl phenolic resin with a hardness of 95 degrees and a high styrene resin. Use resin RS, accelerator H and use system hardness up to 85 degrees, etc.