The vulcanized rubber powder processed from waste rubber products is widely used in the production of various rubber products, such as tire treads, rubber floors, rubber soles, hoses, and conveyor belts. The use of rubber powder in rubber polymers can significantly reduce the cost of raw materials, but the addition of rubber powder will reduce the mechanical strength of vulcanizates to a certain extent. Why? How can rubber product manufacturers improve the mechanical strength of rubber products containing rubber powder?
1. Adjust the vulcanization system
Adding rubber powder to the rubber compound will cause sulfur to move from the rubber phase to the rubber powder direction during vulcanization. The sulfur concentration at the interface between the rubber powder and the rubber decreases and the number of crosslinks decreases; the average crosslink density of the rubber phase decreases and the interface cannot be fully formed 2LLYY1225 The cross-linking bond leads to a decrease in the tensile strength of the vulcanizate added with rubber powder. Rubber product manufacturers appropriately adjust the vulcanization system to improve the physical and mechanical properties of rubber polymers mixed with rubber powder. The specific measures are as follows:
(1) Increase rubber vulcanization concentration;
(2) Cooperate with vulcanization accelerator with fast vulcanization speed;
(3) Give up the sulfur vulcanization system and try the peroxide vulcanization system and the sulfur-free vulcanization system;
(4) Combined use of rubber (the vulcanization speed and solubility of different types of rubber are different).
2. Use the third substance
The appropriate amount of hexamethylenetetramine (H), resorcinol (R) or modified phenolic resin is used in the formula of rubber products mixed with rubber powder to slow down the decrease in the tensile strength of the rubber after adding rubber powder. Improve rubber tear strength. In actual production, resorcinol and hexamethylenetetramine are generally added when the rubber is plasticized. When the blending ratio of resorcinol and hexamethylenetetramine is controlled at 1/0.75, the physical and mechanical properties of the vulcanizate will be better, the tensile strength and hardness of the rubber compound will be improved, and the elongation at break will not change much.
Rubber powder and multifunctional additives PA can produce a synergistic effect. After adding an appropriate amount of multifunctional additive PA to a rubber compound containing rubber powder during mixing, the tensile strength and elongation at break of the mixed rubber are increased, and the tear strength, wear resistance and flex resistance are significantly improved. It should be noted that the amount of zinc oxide, stearic acid, and accelerator in the formulation of rubber products using PA should be appropriately reduced.
When using rubber powder to reduce the raw material cost of rubber products, rubber product manufacturers choose appropriate types of rubber powder, rationally adjust the vulcanization system, and appropriately use the third substance. This can not only prepare rubber products with mechanical strength to meet the needs, but also significantly reduce the cost of raw materials.
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