Rubber has good elasticity, but this precious property poses great difficulties in product production. If the elasticity of raw rubber is not first reduced, most of the mechanical energy is consumed in the elastic deformation during the processing process, and the required shape cannot be obtained. Rubber processing technology has certain requirements for the plasticity of raw rubber, such as mixing, which generally requires a Mooney viscosity of around 60, and rubber wiping, which requires a Mooney viscosity of around 40, Otherwise, it will not be possible to operate smoothly. Some raw adhesives are very hard, have high viscosity, and lack basic and necessary process properties – good plasticity. In order to meet the process requirements, the raw rubber must be plasticated to cut off the molecular chain and reduce the molecular weight under mechanical, thermal, chemical and other actions. A plastic compound that temporarily loses its elasticity and becomes soft and malleable. It can be said that raw rubber molding is the foundation of other technological processes.
The purpose of raw rubber molding is to: firstly, to obtain a certain degree of plasticity for raw rubber, making it suitable for mixing, rolling, extrusion, forming, vulcanization, as well as the requirements of processes such as rubber slurry and sponge rubber manufacturing; The second is to homogenize the plasticity of the raw rubber in order to produce a rubber material with uniform quality.
After plasticizing, the physical and chemical properties of raw rubber also undergo changes. Due to the strong mechanical force and oxidation, the molecular structure and molecular weight of rubber will change to a certain extent, so the physical and chemical properties will also change. This is manifested in a decrease in elasticity, an increase in plasticity, an increase in solubility, a decrease in viscosity of the rubber solution, and an improvement in the adhesive performance of the rubber material. But as the plasticity of the raw rubber increases, the mechanical strength of the vulcanized rubber decreases, the permanent deformation increases, and the wear resistance and aging resistance both decrease. Therefore, the plasticization of raw rubber is only beneficial for the rubber processing process, and is not conducive to the performance of vulcanized rubber.
Post time: Jul-26-2023
