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How to adjust the viscosity of rubber?
Release time:2015/7/7 16:47:20 Clicks:


How to adjust the viscosity of rubber?
Rubber or rubber mix viscosity can be used for characterization of semi-finished products in flowers of sulfur forming performance. It affects production efficiency and product quality problems, adapt to the viscosity of rubber material mixing, rolling, extrusion, sulfur, etc. are essential in the process. High viscosity of rubber compound, not good fluidity, sulfide and full model for a long time, easy to cause the appearance of product defects; and viscosity is too small rubber material, mixing and processing of the shear force is not enough, it is difficult to make the complexing agent dispersed evenly, calendering and extrusion tend to stick to the working parts of the equipment.
The raw rubber viscosity depends mainly upon the molecular weight and molecular weight distribution. The bigger the molecular weight, the narrower the molecular weight distribution, the higher the viscosity of rubber. Adjust the rubber molecular weight and molecular weight distribution, can adjust the viscosity of rubber.
Plastic refining can reduce the viscosity of plastic material. At present most of rubber Mooney viscosity range is wide, can meet the requirements of the performance of different compound, in a wide range with some of Mooney viscosity of rubber. Most synthetic rubber and SMR series of natural rubber Mooney viscosity in the 50-60. These Mooney appropriate rubber, does not need to be after plastic refining process can be directly used for the subsequent processing. And those with higher Mooney viscosity of raw rubber, smoke, particles of natural rubber, ENR, Cr and high Mooney viscosity of synthetic rubber, you must first after plastic refining process, the Mooney viscosity value is reduced to below 60, in order to mixing.
Adding rubber peptizer, can improve the mixing effect, reduce energy consumption, the adjustment of compound viscosity. Such as M or DM, which can make the viscosity of the natural rubber decrease when the plastic is added.
The nature and amount of filler effect on glue viscosity greatly. With the decrease of the particle size of carbon black, the structure and the amount of the material increase, the viscosity of the adhesive is increased; the smaller the particle size is, the more influence on the viscosity of the compound is. When the amount of carbon black was increased, especially in more than 50 copies, the effect of carbon black structure became significant. Under high shear rate, the effect of the type of carbon black on the viscosity of the adhesive is decreased. Increasing the degree of dispersion of carbon black (extended mixing time) can also reduce the viscosity of the compound.
Softening plasticizer is one of the main factors which affect the viscosity of rubber material, it can reduce the viscosity of the material significantly, and improve the process performance.
Different types of softening plasticizer have different effects on the viscosity of various rubber compounds. In order to lower the viscosity of the sizing material, in the nonpolar rubber, natural rubber, polybutadiene rubber, styrene butadiene rubber, ethylene propylene rubber and butyl rubber, such as, add oil base softening plasticizing agent is good, and the nitrile rubber, neoprene rubber polar rubber, often uses lipids plasticizers, especially to phthalate plasticizing agent is good. In the requirements of the flame retardant of chlorinated rubber compound, it is also often used liquid chlorinated paraffin, phosphate ester plasticizer.
The use of oil softening plasticizer and lipid plasticizer has little effect on the use of fluorine rubber, and the plasticizer is easy to be volatile at high temperature, so it is not suitable for use. Use of low molecular weight of fluorine rubber, fluorine carbon tetrachloride liquid, can make the rubber compound viscosity reducing 33%-50%.
In styrene butadiene rubber, acrylonitrile butadiene rubber, ternary ethylene propylene rubber and binary ethylene propylene rubber, using unsaturated and acrylate oligomer as temporary plasticizer, can reduce the viscosity of rubber compound and sulfide can form a network structure, improve the hardness of vulcanized rubber. For example, using low molecular weight polybutadiene liquid rubber, liquid rubber, also can achieve the purpose of reducing glue viscosity.