As the global energy situation tightens, solar photovoltaic power generation, as a sustainable alternative to energy, has developed rapidly in recent years and has been widely promoted and applied in countries with abundant solar energy resources (such as Germany and Japan). After nearly a decade of rapid development, China's photovoltaic industry has also entered the forefront of world development. Driven by the international market and domestic policies, a large number of outstanding photovoltaic enterprises such as Wuxi Suntech, Changzhou Tianhe and Tianwei Yingli have emerged, which has driven the development of upstream and downstream enterprises, and China's photovoltaic power generation industry chain is taking shape.


An important component of solar photovoltaic power generation is a high-conversion single-chip solar cell, ethylene-vinyl acetate copolymer (EVA) film, low-iron tempered glass, fluoroplastic, and polyester composite backing film (TPT). The components are heated and laminated under vacuum to form a whole, and finally the anti-corrosion aluminum alloy frame and junction box are installed to become the finished photovoltaic module. In order to prevent water and oxygen in the air from entering the solar photovoltaic cell module, the silicon cell in the module is oxidized, resulting in a decrease in the conversion rate of the silicon cell, and the frame of the photovoltaic cell module must be disposed (ie, the solar panel of the solar panel, the reverse TPT panel) The gap between the aluminum frame and the aluminum frame is sealed by a sealant with good sealing and weathering resistance; the sealant must be sealed and sealed around the casing of the power conversion box (ie, the junction box) to protect the circuit board. Extended service life.


Silicone sealants are particularly durable under harsh conditions compared to other types of sealants. It also has excellent UV resistance and weathering resistance, and can be kept for more than 30 years in harsh environments such as sunlight, rain, snow and seasonal climate change without cracking, brittleness, and deterioration, over a wide temperature range. It has ±50% resistance to deformation and displacement. Photovoltaic cell modules should be used outdoors without any protection. It is resistant to low temperatures in winter (30 ° C), high temperatures in summer (above 80 ° C in sunlight), rain and snow erosion, and ultraviolet aging. Architectural practice has proven that silicone sealants can stand the test and are therefore the most suitable sealants for solar photovoltaic modules.


The common silicone sealant on the market is a condensation type room temperature vulcanized silicone rubber. When such a sealant is vulcanized, small molecular by-products are released. According to the type of by-products, the condensation type room temperature vulcanized silicone rubber can be classified into a type of dealcoholation, deketoxime, deacetic acid, deamidation, and deacetone.


The deacetic acid type silicone sealant is the most sold sealant on the market. Because the by-product released during vulcanization is acetic acid, and acetic acid is corrosive to metal, it is mainly used for the sealing of architectural glass and ceramics, commonly known as glass glue. Less used in industry; the small molecular weight by-products of amide-type silicone sealant which are removed during vulcanization have a boiling point of up to 200 oC, which is difficult to volatilize to form a clean rubber material, and its application is limited. Commercial products are rarely used. The deacetone-type silicone sealant releases neutral and non-corrosive small molecular by-products when vulcanized, and is most suitable for application in the field of electronic appliances. However, due to the difficulty in synthesizing the cross-linking type silicone rubber cross-linking technology, the cost is relatively high. Higher, limited the use of de-acetone type; the removal of the alcohol-free silicone sealant is a low molecular alcohol. Substance (methanol, ethanol), low toxicity, especially non-corrosive to metals, therefore, it is widely used in the construction field (especially building curtain wall) and industry; the ketone is removed when the deodorized silicone sealant is vulcanized. Bismuth (methyl ethyl ketone oxime), which is an alkaline substance, has certain toxicity and has a certain corrosive effect on metals. However, due to its fast vulcanization rate and good performance, it is also widely used in construction and industrial fields.


The cost and performance advantages of the dealcoholic and dissociated type make it the most common silicone sealant currently used on the market.