Oil-swelling rubber is a functional rubber material prepared by adding lipophilic materials (mainly oil-absorbing resin) to rubber raw materials. When encountering petroleum products, it absorbs oil and expands while maintaining basic rubber properties such as elasticity. High-quality swelling rubber in contact with oil has the characteristics of automatic expansion in contact with oil, fast expansion speed, high expansion rate, low cost, and simple processing method. In the actual application process, high Mooney EPDM rubber can be used together with an appropriate amount of butyl reclaimed rubber to prepare oil-swelling rubber.
1. The significance of using butyl reclaimed rubber for EPDM swelling rubber when exposed to oil
EPDM rubber is made by the copolymerization of ethylene, propylene and a small amount of non-conjugated diolefins. The main chain is a saturated alkane structure, which has a certain adsorption effect on oil molecules of saturated hydrocarbons. The air tightness of butyl reclaimed rubber is basically the same as that of butyl rubber 2YLYY56. The production process of rubber products containing butyl reclaimed rubber has low heat generation, high scorch safety, and better dimensional stability of the finished product. Adding butyl reclaimed rubber to EPDM swelling rubber can improve the oil absorption capacity of the vulcanized rubber, increase the oil absorption rate of the EPDM vulcanized rubber, and reduce the cost.
2. Changes in physical properties of oil-swelling rubber added with butyl reclaimed rubber
After using butyl reclaimed rubber in EPDM oil swelling rubber, a small amount of butyl reclaimed rubber can improve the oil absorption rate of EPDM vulcanized rubber. With the continuous increase in the amount of butyl reclaimed rubber, the oil absorption capacity of vulcanized rubber increases, and the oil absorption rate of vulcanized rubber increases more significantly at high temperatures.
In actual production, EPDM generally chooses peroxide vulcanization when encountering oil swelling rubber. But butyl rubber cannot be vulcanized with peroxide, because the use of peroxide (such as DCP) will break the macromolecular chain of butyl reclaimed rubber, which will not be able to cross-link; the cross-linking of EPDM vulcanizate Density decreases, butyl reclaimed rubber increases the oil absorption capacity of the rubber material, and at the same time causes the physical and mechanical strength of EPDM vulcanizate to decrease, such as tensile strength and tensile stress. Therefore, the amount of butyl reclaimed rubber should not be too high.
3. Methods to improve the strength of oil-containing swelling rubber containing butyl reclaimed rubber
When using butyl reclaimed rubber to improve the oil absorption capacity of EPDM swelling rubber when exposed to oil, when rubber product manufacturers choose EPDM with a relatively high Mooney viscosity, the mechanical properties of the finished product will be better. When using peroxide vulcanization, an appropriate amount of cross-linking aid can be used to improve the vulcanization cross-linking network, reduce the amount of DCP, and improve the mechanical strength. When carbon black is used to reinforce EPDM/butyl reclaimed rubber when it encounters oil swelling rubber, the amount of carbon black should be appropriately increased. Carbon black N550 is commonly used. The oil absorption expansion rate and mechanical strength of vulcanized rubber are greater.
There are many details that need to be paid attention to when using butyl reclaimed rubber in EPDM oil-expanded rubber. The editor will have the opportunity to continue to share with you later.
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