The mixability of the compound is to determine whether the mixture is easy to mix with the rubber and disperse evenly. The mixability of the compound mainly depends on the infiltration or miscibility between the compound and the rubber.
The filler has great influence on the mixing performance. Hydrophobic fillers, such as carbon black, are easy to be infiltrated by rubber, so they are easy to mix with rubber and have good mixability. Hydrophilic fillers, such as calcium carbonate, barium sulfate, clay, zinc oxide, magnesium oxide, white carbon black, etc., are not easy to be infiltrated by rubber, so it is difficult to disperse when mixing, but the mixing speed is faster. In order to obtain a good mixing effect, so that the hydrophilic filler can also be well dispersed in rubber, the surface of this type of compound can be chemically modified, commonly used surfactants are stearic acid, high alcohols, nitrogen compounds, some low molecular polymers. Plasticizers, recycled adhesives and other organic compounds (such as accelerators, antioxidants, etc.) are miscible with rubber, so they are generally easily dispersed in rubber. Sulfur and other vulcanizing agents can also dissolve in rubber according to a certain amount. Zinc oxide is a difficult to disperse compound in rubber, and the cost is high, so in the formulation design, the amount should be reduced as much as possible.
The most important blending factors affecting the rolling properties are the raw rubber varieties, followed by the blending agents. The rolling properties of the compound mainly depend on the raw adhesive strength and adhesion of the compound. The main factors affecting the strength of raw rubber are the molecular weight of rubber and the tensile crystallinity of raw rubber. Natural rubber has the best rolling properties, and emulsion synthetic rubber is second; Lysopoly, especially those with a wide molecular weight distribution, is poor. Therefore, we should try to improve the strength of raw rubber in the formula. Adding active and structural fillers such as carbon black, white carbon black, hard clay, magnesium carbonate, calcium carbonate, etc. can increase the raw rubber strength of the rubber, can improve the rolling property. However, zinc oxide, barium sulfate, titanium dioxide and so on will make the rolling performance worse. In addition, talc will cause the rubber to produce a tendency to roll off, stearic acid, stearate, wax, oil, ointment and other softeners, also easy to make the rubber roll off. The effective way to improve the rolling properties of synthetic rubber is to use a small amount of natural rubber to increase the strength of the compound.
Dalian FTZ Richon Int'l Trade Co., Ltd. is a professional rubber additives supplier. If you would like to know more about the product, please click on the website and contact us. We'll share you more information.
Website: https://www.ftz-richon.com/
E-mail: info@richon-chem.com
