The biggest feature of fixed base rubber (IIR) is its air tightness, which is widely used Used in inner tubes, rubber plugs, vulcanization bladders and other fields. Due to the low degree of unsaturation, the vulcanization speed of IIR is slow, and the bonding performance with other rubbers and metals is poor, which limits the application of IIR.
Halogenated butyl rubber (HIIR) not only maintains excellent air tightness, but also greatly increases the vulcanization speed and has excellent bonding properties with other rubbers and metals. also improved.
Calcium stearate can be used as a vulcanization speed inhibitor, stabilizer, dispersant and lubricant in HIIR. Its main functions are as follows:
1. Acts as a calcium stearate vulcanization speed inhibitor. It has been proven that when using Zn0 vulcanization system, the vulcanization mechanism of HIIR is a cationic reaction. During the vulcanization process, the presence of Lewis base will inhibit the vulcanization reaction speed to varying degrees.
2. In HIIR, calcium stearate is used as a stabilizer. Different from the halogens on the saturated main chain of PVC, the halogens in HIIR exist at the allyl position on the isoprene on the main chain. They are more active and are more susceptible to detachment during production, storage, processing and use. Halogen will cause product quality to decline.
3. In HIIR, calcium stearate is both a vulcanization speed inhibitor and a stabilizer. The dosage of calcium stearate needs to be determined based on the comprehensive impact on various HIIR properties, such as the vulcanization performance of the mixed rubber, the physical properties of the vulcanized rubber, and the thermal stability properties.
4. In addition, in the production process of halobutyl, calcium stearate also acts as a lubricant in the post-treatment drying process and in the desolventizing process. It acts as a dispersant to control the particle size of the micelles in the glue after desolvation in the coagulation kettle. Micelle particles that are too small are not conducive to post-processing and dehydration, and micelles that are too large are not conducive to transportation and can easily block pipelines.
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