Polyethylene glycol (PEG) is very common and useful in various industries. It mainly neutralizes the acidity of fillers in rubber, accelerates the vulcanization rate and crosslinking density, has good water solubility, and has many organic components. Good compatibility, with excellent lubricity, moisturizing and dispersing properties.
Generally, PEG-4000 is used in the rubber, because the molecular weight of 4000 is solid flake, easy to process, easy to add, difficult to precipitate, and the polymer with medium molecular weight has better compatibility with rubber.
The effects of PEG can be summarized as follows:
It can increase the extruding speed of the rubber material, improve the mold release property, make the surface of the product bright, and also help the drainage of water during vulcanization. When used in tires and rubber molded products, PEG-4000 has a good lubricating effect, making the surface of the product smoother. It can also be used as an internal release agent in the production process of natural rubber and synthetic rubber. The advantage is that it does not volatilize, does not produce graying, and the mold is kept clean after demolding. In addition, the surface of the molded product is smoother and cleaner due to its addition.
It plays a role in adjusting the binding performance of raw rubber and filler (especially white). It also reduces the Mooney and increases the vulcanization rate. It has a better activation effect on thiazole accelerators, which can increase the vulcanization speed and cross-linking. degree. Especially in the formulation of EPDM white CB reinforced extrusion microwave continuous vulcanization. Metal-bonded articles are preferably free of PEG.
Especially for silica, it can be used as a treatment agent for silica to activate the vulcanization system. Wet the surface of acid fillers such as white carbon black. One response is neutralization, and one is similar to overlay. Because acidic fillers adsorb, please note that they are adsorption promoters. The amount used is directly proportional to the amount of acidic surface area of the acidic filler and the like.
When used as an active dispersant in rubber compounds with various fillers and colorants, it can reduce or eliminate the effect of fillers on vulcanization, make various additives uniformly dispersed and extend the scorch time, and improve the physical and mechanical properties of rubber products. In various colored rubber products, the color of the products can be bright.
Due to its polar characteristics, it can also enhance the microwave absorption of non-polar rubber (such as EPDM).