First: raw rubber system
1) Rubber and plastic is a very common means, and with high styrene, PVC / NBR alloy effect can also be hardened.
2) Change the type of plastic grades, but also can improve the hardness.
Second: vulcanization promotion system
1) By increasing the curing agent to increase the cross-chain density, increase the hardness, such as increased substantial increase the use of sulfur, etc.
In the production of recycled rubber products, other materials remain unchanged, adding the appropriate amount of sulfur can be to a certain extent, improve the hardness of rubber products. (100 copies of plastic, the highest amount of sulfur 4 to 5 copies)
2) Add the resin. The incorporation of the resin in the manufacture of the recycled rubber article can increase the hardness of the rubber article.
3) Part of the secondary vulcanization products, increasing the degree of cross-linking to improve hardness.
Third: reinforcing filling system
1) Carbon black was added. Carbon black can be used as a filler in rubber compounds to change the hardness of rubber products.
2) The replacement of carbon black varieties, the same rate of plastic under the premise of hardness can also be substantially increased.
3) Add the powder, the hardness becomes high, the effect is very good, but only for molded products Oh.
Fourth: plasticizing softening system
Reduce the amount of rubber oil. Rubber oil softening effect, in the rubber products by adding thermal expansion, reducing the interaction between the polymer. Reduce the amount of rubber oil equivalent to reduce the softening effect of rubber products, played a role in improving the hardness.