Pentaerythrityl tetrastearate products belong to the low-melting-point category and are recommended to be added after the base material has been dehumidified. Additionally, the pentaerythritol stearate series is increasingly being used as a raw material in the production of rubber additives. Previously, pentaerythritol stearate (PETS) was primarily employed during the plasticizing process of rubber to serve as a plasticizer and lubricant. It can now be directly used as an environmentally friendly and highly efficient rubber lubricant and dispersant. However, it is now being more widely applied in the production of rubber pre-dispersed masterbatch materials, gradually becoming an essential dispersant component (currently, many manufacturers producing rubber pre-dispersed masterbatch materials are sourcing it).  In the rubber industry, when used as a dispersant and lubricant component in rubber additive pre-dispersed masterbatch materials, both PETS-4 and PETS-3 provide internal and external lubrication effects. PETS-4 primarily focuses on external lubrication, while PETS-3 emphasizes internal lubrication (common processing aids for highly dispersible pre-dispersed masterbatch materials include SRPW, stearic acid, PETS, and zinc fatty acid. Since the processing temperature of pre-dispersed masterbatch materials typically does not exceed 80°C and is usually discharged at 60°C, considering the melting point factor, the primary processing aids for pre-dispersed masterbatch materials are now predominantly PETS or stearic acid, with an addition dosage of 3-5 phr. In conventional weakly polar carriers such as EPDM, SBR, and BR, stearic acid serves as an internal lubricant, while PETS acts as an external lubricant. Stearic acid may affect vulcanization speed and is generally not recommended for use, although in some cases, its viscosity-reducing effect is notable and may be considered. PETS does not impact vulcanization speed and delivers excellent dispersant and lubricant performance).  Therefore, in addition to considering internal and external lubrication, the effects on kneading and granulation should also be taken into account. Excessive external lubrication during the kneading process can prevent mechanical forces from effectively converting into shear forces, leading to poor dispersion. Similarly, excessive internal lubrication may cause it to precipitate on the polymer and powder surfaces, thereby reducing friction with mechanical surfaces and effectively functioning as an external lubricant. Thus, when determining the specific dosage, it is advisable to conduct multiple trials based on the designed formulation.

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