Butyl rubber has excellent air tightness, water resistance, heat aging resistance, chemical stability and good electrical insulation. Butyl reclaimed rubber retains the basic performance characteristics of butyl rubber. It can be used alone or in combination with butyl rubber to produce inner tube, tubeless tire air seal layer, rubber bladder, sealing washer, anti-corrosion lining, pipeline, conveyor belt and waterproof materials, reducing costs. When using butyl recycled rubber to produce rubber products, the selection of reinforcing agents and fillers directly affects the cost and performance of rubber products.
1. Tips for selecting carbon black in the formula of butyl recycled rubber products
Carbon black is the most commonly used reinforcing filler in rubber product production, and its reinforcing effect in butyl recycled rubber depends on the particle size, structural degree, and surface activity of carbon black.
In actual production, the tensile strength of butyl recycled rubber vulcanizate slightly decreases with the increase of carbon black dosage, with a significant decrease in fine particle carbon black; The constant elongation stress increases with the increase of carbon black content, while the hot cracking method of carbon black remains basically unchanged; The elongation at break of butyl regenerated rubber vulcanizate decreases with the increase of carbon black dosage, while the elongation of butyl regenerated rubber vulcanizate using fine particle hot cracking method carbon black increases with the increase of its dosage.
In addition, the hardness of butyl regenerated rubber vulcanizate increases with the increase of carbon black content, while the elasticity decreases with the increase of carbon black content; The compression permanent deformation decreases with the increase of carbon black dosage, especially for ultra wear-resistant carbon black 2SLYY426, and the increase in hot cracking carbon black is not significant. When using ultra wear-resistant carbon black, medium ultra wear-resistant carbon black, and high wear-resistant carbon black for reinforcement in butyl regenerated rubber, the tear strength of the vulcanized rubber will decrease with the increase of carbon black dosage, while the tear strength of the vulcanized rubber will increase with the increase of other types of carbon black dosage.
2. Tips for selecting white fillers in the formula of butyl recycled rubber products
When using butyl recycled rubber to produce rubber products, white carbon black, clay, calcium carbonate, and talc powder are commonly used as white fillers.
The white filler with the best reinforcement effect in butyl regenerated rubber is white carbon black, second only to carbon black; The particle size of white carbon black is similar to that of carbon black, and its surface activity is relatively high. Mixing is not particularly difficult, and the process operation is similar to that of carbon black. It should be noted that white carbon black will delay vulcanization, and an appropriate amount of diethylene glycol or polyethylene glycol needs to be added to improve the vulcanization speed of butyl regenerated rubber vulcanizate.
Ceramic clay has a certain degree of reinforcement in butyl recycled rubber, with a reinforcement effect second only to white carbon black and superior to calcium carbonate. It can effectively improve the tensile strength and elongation stress of butyl recycled rubber vulcanizate. When using butyl recycled rubber to produce molded and extruded products, hard clay can be used, which has good reinforcement, vulcanized rubber has stiffness, and semi-finished products have little shape change during processing; When using butyl recycled rubber and butyl rubber together to prepare wires and cables, calcined clay can be used with good insulation performance. The clay is acidic and has a tendency to delay vulcanization. It is recommended to add a small amount of diethylene glycol.
Calcium carbonate is the largest white filler used in butyl recycled rubber products, with a relatively small reinforcement effect. It is mainly used for compatibilization and cost reduction. Calcium carbonate has good mixing characteristics, stable performance, and low Mooney viscosity, especially suitable for sponge rubber.
Talc powder is a general term for magnesium silicate. Needle like and granular talc powder has little reinforcing effect in butyl recycled rubber, and is mainly used for rubber products with constant hardness that require compatibilization; Flaky talc powder can improve the elongation stress of butyl recycled rubber vulcanizate, reduce water absorption, and improve the electrical properties of the rubber material.
Other reinforcing agents and fillers will also be used in the production of butyl recycled rubber products. The editor will continue to discuss related issues with you in the future.
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