In the use of conditional glue and sealing glue to be used in a certain environment, working conditions have an important impact on the bonding performance. In the conditions of use, there are stress conditions, ambient temperature and humidity, chemical media conditions, outdoor conditions and so on.
(1)stress situation. When the adherend is subjected to peeling force and uneven pulling force, it is possible to use a good toughness rubber, such as rubber glue, polyurethane glue, etc.; when subjected to uniform pulling force and shearing force, the hardness and strength can be selected. High glue, such as epoxy glue, acrylate glue.
(2)temperature conditions. Different glues have different heat resistance. Different glues are used depending on the temperature.
(3)humidity. Moisture and moisture are detrimental to the stability of the bonding interface and can be said to be harmful and unhelpful. Because the water molecule is small in volume and large in polarity, it penetrates and diffuses, and acts as a hydrolysis to break or completely disengage the bonding surface, resulting in a decrease in bonding strength and durability. Adhesive parts require good water resistance, epoxy glue, polyurethane glue, etc.
(4)Chemical media. Chemical media mainly refers to acids, alkalis, salts, solvents, etc., different types of glue, different curing conditions, and different media resistance. Therefore, glue and sealant should be selected according to the medium in contact with the adherend.
(5)outdoor conditions. The conditions for the outdoor use of the glue joints are more complicated. Temperature changes, wind and rain, sun and ice, etc., will accelerate the aging of the rubber layer and shorten the service life. Therefore, under outdoor conditions, glues with high temperature curing and weathering resistance should be used for bonding, such as phenolic acetal rubber, epoxy-butyl nitrile rubber, and silicone sealant for sealing.