Development And Application Of Release Coating For Non-asbestos Fiber Composite Gasket Materials

"Sticking to flanges" is a problem encountered frequently in the use of non-asbestos gasket materials that makes engine maintenance and gasket replacement extremely difficult to perform. With the development of sealing technologies, the requirements for gasket materials are gradually increasing. An example is that the release performance of non-asbestos fiber gaskets is now often demanded. As the result, it has become an essential task to develop an environmental-friendly release coating that has not only outstanding release performance but also minimum adverse effects on basic properties of the gasket materials.A method to determine the adhesion force generated between gasket materials and flange surfaces under the action of compressive stress and high temperature is first developed in this paper. It includes the design of measurement device and the development of testing procedure.Release coating formulas are then developed through studying the effects of types and dosages of various coating components and coating weight on release performance of the coatings. Many different types of release agents and pigments which are commonly used in other industries are thoroughly experimented and the coating formula is thus optimized. It is showed that the release performance is at the optimum when organic silicon wax emulsion is used as the release agent and its dosage is at 10%, CMC is used as the coating binder at the dosage of 15%, and the coating weight is at 6-7 g/m2.Finally, the effects of release coating on basic properties of non-asbestos fiber composite materials are evaluated. The results showed that after applying the release coating developed in this paper at a proper rate, the tensile strength, compression and recovery rates, creep relaxation and hot compression strength of the fiber gasket materials are not adversely affected, while the nitrogen leakage rate increases moderately. In conclusion, application of the release coating will not significantly alter the basic properties of the fiber gasket materials.