Polyethylene glycol (PEG) is very commonly used and is used in all walks of life. In rubber, it mainly neutralizes the acidity of fillers, accelerates the vulcanization speed and cross-linking density, has good water solubility, and interacts with many organic substances. The components have good compatibility, excellent lubricity, moisturizing properties, dispersibility, and can also be used as antistatic agents and softeners.
Generally, PEG-0 is used in rubber. If the molecular weight is too low, the compatibility is not good and it is easy to precipitate. It is liquid and difficult to add. If the molecular weight is too high, there will be few alcohol groups per unit mass (hydroxyl groups). (low value), the effect of neutralizing acidity is poor, because the molecular weight of 0 is a solid sheet, easy to process, easy to add, and not easy to precipitate. The medium molecular weight polymer has better compatibility with rubber, so PEG-0 is generally selected.
The role of PEG
1. Processing aids can increase the extrusion speed of the rubber compound, improve the demoulding properties, make the surface of the product bright, and help discharge moisture during vulcanization. When used in tires and rubber molded products, PEG-0 has a good lubrication effect, making the surface of the product smoother. In the production process of natural rubber and synthetic rubber, it can also be used as an internal release agent. The advantage is that it is non-volatile, does not produce graying, and the mold remains clean after demoulding. Moreover, the surface of molded products is smoother and cleaner due to its addition.
2. Vulcanization activator plays the role of adjusting the bonding properties of raw rubber and fillers (especially white). It also has the function of reducing Mooney and increasing the vulcanization rate. It especially has a good activation effect on thiazole accelerators. Polo Shamu 188 can increase the vulcanization speed and cross-linking degree. Especially in the formula of EPDM white CB reinforced extrusion microwave continuous vulcanization. It is best not to use PEG for products bonded to metal.
3Quenching agent. The activator of acidic fillers, especially for silica, can be used as a treatment agent for silica to activate the vulcanization system. Wetting the surface of acidic fillers such as silica. One reaction is neutralization and one is similar to coverage. Because acidic fillers will adsorb, please note that they are adsorption accelerators. The usage amount is directly proportional to the acidic surface area of the acidic filler, etc. We can basically understand that the acidic surface has been neutralized. Of course, acidity will also occur in other vulcanization reactions, such as HS, etc. Let zinc oxide take care of that.
4. Activated dispersant, when used as an activated dispersant in rubber compounds using various fillers and pigments, can reduce or eliminate the impact of fillers on vulcanization, make various additives evenly dispersed and extend the scorch time, and improve the physical properties of rubber products. Mechanical behavior. Among all kinds of colored rubber products, the products can be brightly colored.
Source: Rungke Rubber Technology
