High-strength reclaimed rubber generally refers to a tire reclaimed rubber with a tensile strength of 10-18MPA which is produced by the process of grinding, desulfurization, magnetic separation and lower sheet molding of more than 900 used tires. The high-strength reclaimed rubber produced by the traditional production process not only causes environmental pollution and a large amount of cost waste, but also the quality of the reclaimed rubber product cannot be guaranteed. Therefore, the production of high-quality high-strength reclaimed rubber needs to abandon the old ideas and break the traditional concept.
High-strength reclaimed rubber has high strength, good elasticity, small specific gravity, low Mooney viscosity and easy operation. The traditional high-strength reclaimed rubber production process is rubber powder - desulfurization (depth) - rubber refining - refining. However, the performance of the vulcanized rubber of the waste rubber tire after deep desulfurization will be greatly reduced; the time of reclaimed rubber compounding is short, and the amount of softener is large, which leads to a decrease in the performance of the reclaimed rubber obtained. Therefore, the traditional high-strength reclaimed rubber production method must be discarded. In order to improve the quality of high-strength reclaimed rubber and improve production efficiency, a new process of high-strength reclaimed rubber should be used.
At present, there are many new processes for the production of high-strength reclaimed rubber, such as:
1. High-temperature and high-pressure method in steam method (25-30KG/cm2 pressure): mix the rubber powder and regenerant uniformly, put it into a closed high-pressure container, and pass the direct steam to desulfurization regeneration; this method needs sophisticated and advanced Production equipment, investment is large.
2. Water-oil method in cooking method: The desulfurization equipment is a vertical desulfurization tank with stirring, and steam of 0.9-0.98 MPa (9-l0 kgf/cm2) is introduced into the jacket. The tank is filled with warm water (80 ° C) as a heat transfer medium; in the desulfurization, the rubber powder and the regenerant which have been mechanically removed are added to the tank, and the stirring time is about 3 hours. Although this method has many equipments, it has a high degree of mechanization and the product quality is excellent and stable.
3, the screw extrusion method in the mechanical method: the main machine is a screw extruder (similar to the rubber extruder), the screw diameter is 6, 8, 12in three. There is a jacket inside the casing, and the temperature is controlled by steam or oil (about 200 °C). During the operation, the rubber powder and the regenerant are mixed and fed into the machine in advance, and the rubber material can be discharged from the discharge port after 3 to 6 minutes under the shearing action of the screw. This method is continuous production, with short cycle, high efficiency and excellent product quality. However, due to the large wear of the screw and the inner sleeve, the material requirements of the equipment are relatively high.
There are still many new processes for the production of high-strength reclaimed rubber. Basically, the following principles must be followed:
1, the production process safety: especially high pressure temperature dynamic seal maintenance and repair.
2, high-strength reclaimed rubber quality is stable: high-strength reclaimed rubber if it contains a large amount of water in desulfurization, it needs to be filtered, otherwise it will cause uneven desulfurization of the micelle and rubber block, and the quality of reclaimed rubber will be good and bad, unstable; After desulfurization of the reclaimed rubber, an optimized combination, especially secondary sulphur, is carried out.
3. It is best to use staged desulfurization: high temperature, medium temperature and short time desulfurization, it is inevitable that the rubber powder will agglomerate and agglomerate, and the quality of the reclaimed rubber is unstable. If the fine rubber particles are used for desulfurization, the refining is obviously increased, the reclaimed rubber has high hardness, the Mooney is large, and the surface is rough. Therefore, it is preferable to adopt a method of segmental desulfurization.
4, desulfurization cooling: the traditional dynamic desulfurization method for the production of reclaimed rubber desulfurization is generally directly down on the ground to naturally cool, this will significantly reduce the rubber performance; increase the desulfurization water consumption, or directly placed in the water to cool, it will cause late rubber mixing difficulties Therefore, it is better to use a closed jacket to cool the spiral conveying to achieve better results.
5. The temperature of the rolling mill should not be too high: the plasticity of the rubber obtained by increasing the rolling temperature in order to shorten the rubberizing time is pseudo-plasticity. After the thermal molecular motion is cooled, the regenerative rubber is restored, and the high-strength reclaimed rubber is again. Raise; therefore, the temperature of the rubber roller is preferably lowered appropriately to obtain true plasticity.
Exclusive original article [commercial authorization] reprint, excerpt and excerpt in any form are prohibited without written authorization. Focus on Hongyun rubber: learn the process formula and raw material technology of producing rubber products from recycled rubber to help you reduce costs and increase profits