Two ways to reduce Final Mooney Viscosity
Often, the formulator will add peptizers to reduce Final Mooney Viscosity. The principle is that the long molecular chain of natural rubber is broken into small molecular chains by the peptizer. Under normal circumstances, the decrease in Final Mooney Viscosity is proportional to the amount of peptizer. For example, adding 300 grams of peptizer reduces the Final Mooney Viscosity by 5. Adding 600 grams, the Final Mooney Viscosity dropped by 10. Therefore, when the Final Mooney Viscosity of the compound is too high, the formulation engineer or process technician will increase the amount of peptizer to significantly reduce the Mooney viscosity to the expected range.
The above is a chemical method to reduce Final Mooney Viscosity of the rubber compound, and another method is a physical method. The physical method is to use mechanical shearing force to break the macromolecular chain of natural rubber into small molecular chains to reduce Final Mooney Viscosity.
Both of the above methods have advantages and disadvantages. The chemical method has obvious effect of reducing Final Mooney Viscosity and low cost, but it seriously damages the molecular chain, which affects the performance of rubber compounds and rubber products. The Final Mooney Viscosity of the physical method has a small decrease and high cost, but it has little damage to the molecular chain, and has little impact on the performance of the rubber compound and rubber products. Which one to choose depends on the way of weighing the interests of the factory and the habits of engineers.