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  • Making method of sponge rubber
    Dec 07, 2017

    1. Pressure molding processing

    Sponge rubber of the normal pressure molding process, is to contain sufficient foaming agent of the mixing of plastic material in the mold cavity, and then vulcanization foaming. Note that the plastic materials do not fill the mold cavity, leaving a part of the space for plastic foam expansion. Vent holes should be opened above the mold cavity so that the air above the mold cavity will be discharged when the rubber expands. Add people before the plastic material, first in the mold cavity in the wall pad piece of cloth or coated with talcum powder, vulcanization can be the bottom of the gas escaping from the discharge. Normal pressure molding foaming requirements of low viscosity, so that the plastic material in the mold cavity fluidity, easy to expand. The foam-hole structure of sponge rubber products made by this method can be perforated structure, and may be closed-pore structure, depending on the variety and dosage of foaming agent and the vulcanization speed of the rubber compound.

    2. High pressure Molding process

    The sponge rubber is generally divided into two stages of pre vulcanization and final vulcanization. (1) Pre-vulcanization stage, like the traditional dry rubber molding vulcanization, will contain foaming agent of the plastic filled with mold cavity, after the 135?:l45°c under pressure pre-vulcanization 25?35min, and then unloading pressure. As the mold cavity is filled with plastic material, die cavity closed after the mold, with the vulcanization, blowing agent decomposition of the amount of gas increased, so that the pressure in the bubble gradually increased. Unloading pressure, due to the release of external pressure, bubble in the high pressure of the bubble quickly in the incomplete crosslinking of the rubber material expansion, resulting in a small closed-hole sponge. The foaming expansion rate can be controlled by formula design and by adjusting the vulcanization time and temperature. The final size of the product and the complete vulcanization of the rubber are completed at the end of the second phase.

    3. Continuous Extrusion process

    The method is the most effective and economical processing method for preparing sponge products in rubber industry. is to contain the foaming agent of the plastic material through the extruder extrusion or calendering to a certain thickness of the film, and then extruded semi-finished products or calendering film continuous through the hot air furnace or liquid vulcanization medium, microwave ovens, boiling bed and other continuous vulcanization equipment foaming, stereotypes. These continuous vulcanization process in the normal pressure or high temperature, foaming agent decomposition speed is very fast, to make the rubber material foaming, the vulcanization speed of the rubber is also very fast, in the formulation design attention to select the vulcanization speed of the rubber and vulcanization system.