It is well known that vulcanization and foaming of sponge foamed rubber products are carried out simultaneously. Since the foaming speed is difficult to adjust, the vulcanization speed is adjusted by adjusting the vulcanization system and vulcanization parameters of the sponge rubber to match the foaming speed. When using recycled rubber to produce sponge foam rubber products to reduce production costs, it is necessary to rationally select the type and amount of reclaimed rubber, and to adjust the vulcanization system of the sponge foam products, then when determining the vulcanization system of the reclaimed rubber sponge products in actual production, What are the principles to follow?
Theoretically, the principle of determining the vulcanization system of reclaimed rubber sponge rubber products is to match the vulcanization speed of the rubber compound with the decomposition rate of the foaming agent. Different types of reclaimed rubbers need to be combined with different vulcanization systems when preparing sponge foam rubber.
Latex reclaimed rubber, tire reclaimed rubber, and isoprene reclaimed rubber are usually selected from the sulfur-accelerator vulcanization system. The sulfur dosage is controlled at 1.5-3 parts. The accelerator can be selected as promoter M, accelerator DM, The accelerator CZ, the accelerator DZ, the accelerator TMTD, the accelerator PZ, etc. are used alone or in combination, and the amount is slightly larger than that of the solid reclaimed rubber product, and the decomposition time of the foaming agent is matched by adjusting the sulfurization time by adjusting the amount of sulfur and the accelerator.
When EPDM reclaimed rubber, nitrile reclaimed rubber and other products produce sponge foam seals, oil-resistant foam rubber sheets and other sponge rubbers, it is possible to use peroxide cure systems; however, due to the peroxide content in peroxide cure systems It is calculated according to the crosslinking efficiency of the polymer, so the increase or decrease of the amount can only control the density of the rubber. The sponge foam rubber is produced by using EPDM reclaimed rubber or NBR reclaimed rubber. The vulcanization should be determined according to its half-life at the vulcanization temperature, and generally takes 5-10 times of the half-life of the vulcanization temperature.
When using reclaimed rubber to produce sponge foam rubber products, whether the foaming speed and the vulcanization speed match can directly affect the foaming effect of the sponge rubber, which in turn affects the quality of the reclaimed rubber sponge foam rubber. Among them, the vulcanization speed of the reclaimed rubber is faster than the foaming speed, the viscosity of the rubber compound is increased, and it is difficult to foam; when the vulcanization rate of the reclaimed rubber is slower than the decomposition rate of the foaming agent, the gas decomposed by the foaming agent is difficult to foam, and the foaming efficiency is lowered, and finally The problem of insufficient foaming of the reclaimed rubber sponge rubber and the surface is not smooth.
In the preparation process of reclaimed rubber sponge foam rubber, it is necessary to adjust the vulcanization system according to the product requirements of reclaimed rubber and sponge foam rubber. It is in accordance with the principle of “matching the vulcanization rate of the rubber compound with the decomposition rate of the foaming agent”. To ensure that the reclaimed rubber sponge rubber is evenly foamed and fully foamed.