With the rapid development of China's economy, the application of curtain wall products in many high-rise public buildings will greatly exceed the use of other wall materials, and become one of the main means to beautify the urban landscape. Curtain wall industry has also developed rapidly. Now curtain wall forms are also diverse, and materials are emerging in an endless stream, which injects new development blood into the curtain wall industry. Among them, people are more and more concerned about the quality of curtain wall sealant, because sealant is one of the indispensable materials for building curtain wall, which has the functions of leak proof, waterproof, vibration proof, sound insulation and heat insulation. Silicone sealant has become the preferred sealing material for building curtain wall because of its good anti-ultraviolet ability, resilience and excellent adhesion to common curtain wall materials. With the decrease of large area concealed frame glass curtain wall, metal plate curtain wall and stone curtain wall, the proportion of silicone weatherproof sealant has been increasing, gradually exceeding the silicone structural sealant, becoming the largest amount of silicone sealant used in building curtain wall.
I. Reasons for Manufacturers'Varieties
Many brands of silicone sealants have experienced similar blistering phenomenon, which is not a quality problem after careful testing and repeated replenishment confirmation. Silicone sealant has two types: alcohol sealant and ketoxime sealant. The methanol contained in alcohol sealant during curing process releases gas (methanol begins to volatilize at about 50 degrees), especially when exposed to direct sunlight and high temperature. It is very difficult to breathe through the metal window frames of concrete. In addition, the higher temperature and humidity in summer, the curing will be faster. The gas released by the glue can only run out from the completely cured glue layer, and there will be bubbles of different sizes on the cured glue strip.