Precautions for mixing butyl rubber

Butyl rubber synthesized from isobutylene and a small amount of isoprene has excellent air tightness and water tightness, good chemical stability and thermal stability, and is widely used in the preparation of various inner tubes, steam pipes, water tires, dam bottom layers, gaskets, etc. product. When using butyl rubber to produce rubber products, due to the high cold flow of butyl rubber, the semi-finished products have relatively poor stiffness and are easily deformed, the compounding agent is not easy to disperse during rubber mixing, and the rollability is poor; therefore, it is necessary to strictly control the mixing. refining process.
1. Pay attention to the cleanliness of the equipment before mixing
When butyl rubber is mixed, other rubbers or impurities, especially rubber with high degree of unsaturation, are mixed into the mixing equipment, which directly affects the quality of the rubber compound. In severe cases, the finished butyl rubber products will be directly scrapped. Therefore, the mixing equipment must be cleaned before mixing of butyl rubber, and the mixing equipment should be checked and maintained regularly during normal use.
2. Pay attention to the mixing process conditions when mixing
Butyl rubber has low self-cohesion and poor self-adhesion. The rubber compound is easy to break up, and the process of re-agglomeration into the whole is very slow. Therefore, higher mixing temperature and longer mixing time are required during mixing. During the mixing process, 2YLYY114-MXF pays attention to the change of mixing temperature in time, strictly controls the mixing temperature, and avoids that the temperature is too high or too low to affect the quality of the mixed rubber and the quality of the finished product. When the butyl rubber is mixed with an internal mixer, the mixing temperature is generally controlled at 150 ° C to promote the uniform dispersion of the compounding agent.
3. Points to note when mixing different rubber mixers
(1) Kneading with an open mill: When using an open mill to knead butyl rubber, the feeding method (that is, adding rubber and compounding agents after the rubber roll is introduced) is used to overcome the problem of poor butyl roll performance. The feeding process The slow feeding is carried out in batches. First, half of the raw rubber in the formula is repeatedly thinned with a small roll gap, and the other half of the raw rubber is added after waiting for the roll to improve the mixing effect. When mixing, the temperature of the front and rear rolls should be properly controlled, and the temperature of the front roll should be 15-20°C lower than that of the rear roll, so as to adapt to its cooling roll performance.
(2) Mixing with an internal mixer: When using an internal mixer to mix butyl rubber, appropriately increase the loading capacity, and the capacity is greater than 10%-20% of the natural rubber; the pressure of the upper jack is higher than the pressure of the lower jack during mixing . When the amount of compounding agent used in the formulation of butyl rubber products is large, the two-stage mixing method or the reverse mixing method can be used for the mixing process.