Butyl reclaimed rubber has the basic performance characteristics of butyl rubber, good air tightness, heat resistance and corrosion resistance, and is widely used in the production of various butyl rubber products, especially inner tube products. The inner tube is an important part of the bicycle, and its performance directly affects the comfort and safety of riding; At present, bicycle inner tubes are mainly made of butyl rubber/butyl reclaimed rubber; How much butyl reclaimed rubber is appropriate for bicycle inner tubes? And how to design an inner tube formula containing butyl reclaimed rubber?
1. The mixing ratio of butyl reclaimed rubber in bicycle inner tubes
Butyl rubber is made of waste butyl inner tube as raw material desulfurization and regeneration, with low air permeability and much lower price than butyl rubber, which is an ideal raw material for replacing butyl rubber to produce bicycle inner tubes. In actual production, the mixing ratio of butyl reclaimed rubber 2SLYY1218 in bicycle inner tube needs to be determined according to the performance index of butyl reclaimed rubber and the technical requirements of bicycle inner tube, and the general mixing ratio is about 20-30%; Adjust the formula appropriately, the proportion of butyl reclaimed rubber in the bicycle inner tube can be appropriately increased, and some products can completely use butyl reclaimed rubber.
The use of butyl reclaimed rubber instead of part of butyl rubber to produce bicycle inner tubes can not only reduce the cost of raw materials, but also improve the vulcanization performance of the rubber compound, increase the extrusion speed, reduce the extrusion temperature, and then improve the production efficiency.
2. Key points of optimization of the formula of bicycle inner tube mixed with butyl reclaimed rubber
When using butyl reclaimed rubber to reduce the production cost of bicycle inner tubes, unreasonable formula design directly affects the quality of finished inner tubes, especially the strength of joints. In general. Appropriately increasing the glue content of the whole formula can improve the strength of the joint; However, the proportion of butyl rubber is too high and will affect the cost, so the optimization formula will further improve the comprehensive index of bicycle inner tubes.
(1) Reasonable design of vulcanization system: the length of scorching time affects the strength of bicycle inner tube joints. In general, the scorching time of ordinary sulfur vulcanization system is short, and the operation safety is poor; The vulcanization time of the effective vulcanization system is too long, and the tensile elongation of the vulcanized rubber is high. The scorching time of the semi-effective vulcanization system is moderate, and the strength of the butyl inner tube joint is higher.
(2) The smaller the particle size of carbon black, the larger its specific surface area, and the larger the contact area with rubber molecules, so as to improve the viscosity and reinforcing effect of rubber more effectively. Choose carbon black that is more favorable to the viscosity of vulcanizing agent, such as N220/N330/high structure carbon black, etc., and appropriately increase the amount of carbon black, improve the viscosity and reinforcing effect of butyl reclaimed rubber vulcanizing adhesive, and improve the strength of butyl inner tube joints to a certain extent.
(3) Appropriate use of tackifiers with excellent performance.
3. Butyl rubber/butyl reclaimed rubber is used to produce a vulcanized formula for bicycle inner tubes
90 parts of butyl rubber, 15 parts of butyl reclaimed rubber, 3.5 parts of zinc oxide, 1 part of stearic acid, 0.1 parts of poly-p-nitrosobenzene, 62 parts of carbon black, 25 parts of paraffin oil, 0.5 parts of accelerator DM, 1.4 parts of accelerator TMTD, 1.5 parts of sulfur; Total: 200 copies.
60 parts of butyl rubber, 80 parts of butyl reclaimed rubber, 5 parts of zinc oxide, 1 part of stearic acid, 70 parts of carbon black, 3 parts of antioxidant, 25 parts of softener, 3.5 parts of tackifier, 3 parts of accelerator, 0.5 parts of sulfur; Total: 251 copies.
It is very important to use the appropriate amount of butyl reclaimed rubber with excellent performance in the production of bicycle inner tubes, reasonably determine the proportion of butyl reclaimed rubber, and appropriately adjust the formula. In addition, bicycle inner tube manufacturers can further improve product quality and reduce costs by optimizing the mixing process and vulcanization process, thereby improving the competitiveness of the bicycle inner tube market.
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