Plate heat exchanger is an important part of the heat exchange technology in process industrial equipment. The elastic sealing gasket, which conducts sealing between various plate thermal sheets, is a kind of vulnerable part, as well as a kind of part prone to aging under natural conditions. The service life of elastic sealing gasket has an important influence on the service life of plate heat exchanger. If the sealing gasket hardens and loses the original elasticity, the heat exchanger will not function properly.