1. What are the types of silica dispersants?
The production of carbon black products must only rely on external forces to achieve a stable carbon black dispersion system, which requires a carbon black dispersant.
The method is to add a dispersant to the carbon black dispersion equipment, so as to improve the performance of carbon black and achieve the purpose of dispersion.
Commonly used carbon black dispersants can be divided into three types:
①, low molecular dispersant (i.e. surfactant)
In the case of the preparation of the carbon black water-based dispersion system, the low-molecular-weight dispersant (i.e., the surfactant) exerts the carbon black surface adsorption function in the water-based system, and the same performance is the Langmuir type with a long adsorption platform.
②, polymer dispersant
The polymer dispersant is adsorbed at the anchoring end and the solvation end extending to the dispersion medium, and can be matched according to requirements.
③, mixed dispersant
The mixed dispersant is mainly non-ionic and anionic. This kind of dispersant can be mixed with low molecular weight and high molecular weight to obtain a carbon black water-based dispersion system. This method is relatively simple to operate, and the key is to consider the special synthesis of carbon black dispersant to produce good products.
2. Introduction to PEG400
Polyethylene glycol (referred to as PEG-400) series products are colorless or almost colorless viscous liquid with a slight odor.
Polyethylene glycol with a lower molecular weight can be used as a solvent, co-solvent, O/W emulsifier and stabilizer, and can be used to make cement suspensions, emulsions, injections, etc. Polyethylene glycol with higher molecular weight can increase the viscosity and solidification of low-molecular-weight liquid PEG, and externally compensate other drugs.
3. Addition ratio of white carbon black dispersant
Silica is widely used in the color matching of rubber products, and is mostly used in white, light-colored and colored reclaimed rubber products.
It should be noted that the precipitated silica should be used with caution in the production process of reclaimed rubber, and the silica modified by the surface treatment agent can be used instead of getting wet.
The addition ratio of white carbon black dispersant is as follows:
①. Silica with a pH value above 8: the vulcanization rate of reclaimed rubber is fast.
②. Silica with a pH value below 5: the vulcanization rate of reclaimed rubber is very slow.
Therefore, when producing reclaimed rubber, the manufacturer should use which type and index of silica according to the demand, and add a considerable proportion of active agent, so as to improve product performance.