| A kind of rubber-metal composite gasket of heat resistance and oil resistance used for the seal of automobile engine at relatively low temperature environment (-35℃) has been prepared. As the low temperature resistance and oil resistance of nitrile rubber (NBR) can not be matched highly well, the rubber-metal composite gasket was prepared by painting the NBR coating modified by blending a small amount of acrylic rubber (ACM) onto the surface of the metal.Firstly, the solubility parameters of NBR and ACM were educed by using the theoretical calculation and experimental method, respectively. The similarity of solubility parameters and polarity of NBR and ACM were verified, and NBR has a good compatibility with ACM. Then better solvent of the NBR/ACM was selected mainly according to its solubility parameters and toxicity, volatilization volatility, price and chemical stability.Secondly, the better formula of the NBR/ACM coating (including the category and dosage of reinforcing agent, vulcanizing agent, plasticizers and other additives) was discussed by single factor experiments that test the performance of the coat (such as adhesive strength, hardness degree, heat-resistant, oil-resistant, shearing intensity and cold-resistant) and take the analysis means of TG/DTA.Thirdly, influence of treatment process of metal substrate on coating performance was discussed. The results showed that the adhesion of the metal substate could be enhanced by rubbing the metal substrate with sandpaper and immersing it into the acid.Finally, rubber blending was used for the modification of NBR. In consideration of the good heat resistance, oil resistance of ACM and the similarity of solubility parameters between ACM and NBR, so the ACM was used to blend with NBR. The results showed that NBR was fairly compatible with ACM when NBR and ACM were blended at the ratio of85/15. The NBR/ACM blends of good heat resistance, oil resistance, low temperature resistance and sealing properties could be covulcanized with the amine/sulphur/promoting agent complex vulcanization system, and the crosslinking degree was higher. |
PDF Full Text Request