Natural rubber has good elasticity and high mechanical strength. Butadiene rubber has good elasticity, cold resistance and wear resistance. It can be used to produce automobile tires and cold-resistant rubber products to improve the performance of rubber products. Recycled rubber is used more and more in the rubber products industry. Wide, natural rubber / butadiene rubber and rubber compound also began to blend a certain proportion of reclaimed rubber, why? What role can reclaimed rubber play in natural rubber/butadiene rubber? What issues need to be paid attention to in the selection of raw materials to formula design and then to the production process?
1, pay attention to the choice of reclaimed rubber
The macromolecular chain inside the natural rubber is mainly composed of polyisoolefin. When subjected to external stretching, the macromolecular chain will be oriented along the stress direction to form crystals, which will serve as a reinforcing function. It is a typical self-reinforcing rubber; Synthetic synthetic rubber made of butadiene is a non-self-reinforcing rubber. It is generally used together with natural rubber, neoprene and nitrile rubber. Recycled rubber mainly includes latex reclaimed rubber and tire regeneration according to raw materials of waste rubber products. Glue, nitrile reclaimed rubber, butyl reclaimed rubber and EPDM reclaimed rubber. The main components of tire reclaimed rubber are natural rubber, styrene-butadiene rubber, butadiene rubber and carbon black, and natural rubber/butadiene rubber. It has good compatibility and is an ideal reclaimed rubber raw material used in natural rubber/butadiene rubber.
2, pay attention to the proportion of recycled rubber blending
As a product of recycling and reprocessing of waste rubber products, reclaimed rubber has a certain degree of loss of its own performance during processing. It can be used in natural rubber/butadiene rubber and the amount of rubber used may cause the mechanical strength of the combined rubber to decrease and resist. The flex crack is weakened, so it is necessary to reasonably control the amount of reclaimed rubber according to the actual demand of the rubber product. For example, the tire reclaimed rubber in 50 parts of natural rubber and 50 parts of butadiene rubber should not be used in more than 15 parts, which can reduce the cost of the rubber, improve the processing technology, and Guarantee tire tread performance.
3, pay attention to adjust the natural rubber / butadiene rubber and use collagen formula
In the process of processing, the reclaimed rubber will undergo many processes such as picking, crushing, desulfurization, filtration and molding. Among them, desulfurization is the most important processing step, which is the process of breaking the sulfur bond in the elastic network structure and restoring the plasticity of the vulcanized rubber. However, in this process, the sulfur in the waste rubber products is not separated, and other ingredients of the compounding agent may remain, especially the carbon black in the waste rubber product is basically not affected; therefore, the reclaimed rubber is used. In the case of natural rubber / styrene-butadiene rubber and rubber, it is necessary to adjust the vulcanization system, reinforcing system, filling system, softening system, etc. according to specific needs.
4, pay attention to the rubber mixing process
When refining rubber/natural rubber/butadiene rubber is used for mastication, the natural rubber and the butadiene rubber are fully masticated and then kneaded. It is best to mix the mixture twice in the kneading: adjust the roll gap of the open mill to After the specified value is added, the reclaimed rubber is thinned. After the reclaimed rubber is broken and sticky, plasticizing rubber is added, the roller distance is increased, and the butadiene rubber is added, and the surface of the rubber compound is not visible until the butadiene rubber is not seen. Mixing attention to the roll temperature, control at about 50 degrees Celsius, the order of addition is unchanged.
In actual production, natural rubber / butadiene rubber and rubber mixed with tire reclaimed rubber, in terms of current market prices, the price of natural rubber is about 10,000 yuan / ton, the price of butadiene rubber is about 14,500 yuan / ton, the market The price of high-quality tire reclaimed rubber is only 4,000 yuan / ton, so the use of a certain proportion of recycled rubber in the combination of materials can significantly reduce the cost of raw materials, but also solve some of the environmental pollution of waste tires.