The production method of “recycled rubber + raw rubber” has become the main production method of rubber products industry with the continuous improvement of the quality of reclaimed rubber. The addition of proper amount of reclaimed rubber in the original rubber can reduce the cost of raw materials and improve the glue. Material processing technology performance. Since each rubber compound has its own unique molecular structure and performance characteristics, the reclaimed rubber and the original rubber may not be able to achieve co-vulcanization, but the degree of vulcanization of the rubber directly affects the product quality, so the reclaimed rubber/original rubber is used in combination. When rubber products are used, it is necessary to choose a reclaimed rubber/original rubber and a vulcanization system1JLYY725.
1. What is co-vulcanization
In the rubber products, reclaimed rubber is used to achieve co-vulcanization. On the one hand, the original rubber has almost the same vulcanization speed as the reclaimed rubber, and the other side refers to the co-crosslinking at the interface between the reclaimed rubber and the original rubber. The rubber product blended with the reclaimed rubber is sufficiently and uniformly vulcanized to further improve the quality of the rubber product containing the reclaimed rubber.
2. Why is it difficult to achieve co-vulcanization when the original rubber and reclaimed rubber are used together?
The molecular structure and performance characteristics of different kinds of raw rubber and reclaimed rubber are very different. Even the same compounding agent has different solubility in different rubber compounds. Therefore, when rubberized products are mixed with reclaimed rubber, the vulcanization system is used. The compounding agent has different dispersing coefficients in the compounding compound, and the vulcanization speed of the same vulcanizing system in the two rubber compounds is different, so that it is difficult to achieve co-vulcanization or even an antagonistic effect.
3. How to choose the vulcanization system when the original rubber and reclaimed rubber are used together
Taking butyl reclaimed rubber in EPDM as an example, if a peroxide vulcanization system is selected and DCP is used as a vulcanizing agent, DCP will crack the butyl reclaimed rubber, thereby reducing the vulcanization effect; instead, if it is in EPDM /RIIR and the use of EPDM rubber with DCP, butyl reclaimed rubber with sulfur / accelerator, and then choose the masterbatch blend, you can get a better degree of vulcanization.
Therefore, when the recycled rubber is used in the production of rubber products, and the original rubber and the recycled rubber are used together, the rubber product manufacturer must first compare whether the original rubber and the reclaimed rubber have similar vulcanization speed under the same vulcanization system. Co-crosslinking occurs at the interface of the gum phase.
Generally, when the nitrile rubber and the nitrile reclaimed rubber are used together, the butyl rubber product is mixed with the butyl reclaimed rubber, or the EPDM rubber/recycled rubber is used together to produce the rubber product, the vulcanization effect between the two rubber materials is better; When reclaimed rubber is used in combination with other types of rubber, rubber manufacturers may choose a suitable vulcanization system according to their respective characteristics, and then select the masterbatch to increase the degree of vulcanization of the original rubber/recycled rubber and the rubber, thereby improving the regrind. The performance and service life of rubber products.