Raw material composition and main suppliers of EVA film for solar cell packaging

EVA adhesive film of solar cell is a thin-film product formed by heating, casting and extrusion with production and processing equipment after EVA is used as the main raw material and various modifying additives are added and fully mixed. The production process is as follows:
Raw material proportioning and mixing → vacuum feeding → extrusion → screen changer → melt pipe → metering pump → mold → casting, embossing, cooling and finalization → online thickness measurement → tempering, cooling and finalization → traction and edge cutting → double station central winding → finished product unloading → edge material winding → edge material treatment
EVA adhesive film for solar cell packaging is based on EVA (vinyl acetate content is 30-33%) and supplemented by several modifiers, generally including EVA resin, crosslinking agent, UV absorber, antioxidant (or anti thermal aging agent), UV stabilizer, plasticizer, tackifier, etc., which are extruded and cast into film products. The product is heated in the process of solar cell packaging and produces cross-linking reaction. It is a thermosetting hot melt adhesive film. The cured adhesive film has quite high light transmittance, bonding strength, thermal stability, air tightness and aging resistance.
EVA is the most important material in the packaging of solar cells. EVA packaging film not only plays a role of bonding and sealing for photovoltaic modules, but also plays a vital role in the quality and life of solar cells. In a sense, EVA packaging film determines the life of solar panels. The quality of EVA packaging film depends on raw materials, process formula, production equipment and so on` Therefore, for a good EVA film product, the formula is the key, followed by the process flow, process equipment, production environment, etc.
China is the largest solar cell production base in the world. For a long time, this industry has obvious characteristics of "two ends outward". High-end raw materials need to be imported from abroad, finished products are mainly sold abroad, and domestic enterprises are only engaged in simple assembly. Products are highly dependent on the international market and are greatly affected by the price of international raw materials. The high-end market of EVA adhesive film for solar cells has long been monopolized by foreign chemical giants DuPont, Mitsui and Bridgestone. There is a certain gap between the performance of domestic products and foreign products. The more prominent is the poor weather resistance of the adhesive film, which is easy to turn yellow, affecting its own light transmittance, thereby reducing the photoelectric conversion efficiency of solar modules. DuPont, Mitsui and Bridgestone account for more than 60% of the domestic market, and the high-end market share reaches 100%. The price of imported EVA film is expensive, which is 2-3 times that of domestic film.