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Matters needing attention in butyl rubber mixing

2022-03-29

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 and other products. When using butyl rubber to produce rubber products, due to the large cold flow of butyl rubber, the semi-finished products are relatively poor in stiffness and easy to deform, the compounding agent is not easy to disperse during rubber mixing, and the wrapping roll is poor; therefore, it is necessary to strictly control the mixing process.
1. Pay attention to equipment cleanliness before mixing
When butyl rubber is mixed, other rubber or impurities, especially rubber with high unsaturation, are mixed into the mixing equipment, which directly affects the quality of the rubber material, and in severe cases, the finished butyl rubber products will be scrapped directly. Therefore, butyl rubber must be mixed before the mixing equipment clean, the normal use of the process of timing, timely inspection of mixing equipment, maintenance of mixing equipment.
2. Pay attention to the mixing process conditions during mixing
Butyl rubber itself has low cohesion and poor self-adhesion, the rubber is easy to break, and the process of re-coalescence into the whole is very slow, so higher mixing temperature and longer mixing time are required during mixing. During the mixing process, 2YLYY114-MXF pays close attention to the change of mixing temperature in time, strictly controls the mixing temperature, and avoids the influence of too high or too low temperature on the quality of the mixed rubber and the quality of the finished product. When 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 for Attention in Mixing of Different Rubber Mixing Machines
(1) open mill mixing: the use of open mill mixing butyl rubber, the use of the introduction method (I. e. to be introduced after the rubber roll plus rubber and compounding agent) to overcome the problem of poor butyl roll, the feeding process to take slow feed batch. First, half of the raw rubber in the formula is repeatedly thinly passed with a small roller gap, and the other half of the raw rubber is added after waiting for the roller to improve the mixing effect. During mixing, the temperature of the front and rear rollers should be properly controlled, and the temperature of the front roller should be 15-20 ℃ lower than that of the rear roller to adapt to its performance of the cold roller.
(2) Mixing with internal mixer: When mixing butyl rubber with internal mixer, the rubber filling capacity shall be appropriately increased, and the capacity shall be 10%-20% greater than that of natural rubber; During mixing, the pressure of the upper top bolt is higher than that of the lower top bolt. When the amount of compounding agent used in the formulation of butyl rubber products is large, the mixing process can be carried out by two-stage mixing method or reverse mixing method.

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