Not toxic. According to the iPurchase official website, the main component of the special sealant for photovoltaic solar modules is silica gel, which is non-toxic in itself. Photovoltaic film additives are mainly photovoltaic packaging materials made from EVA resin as raw material by adding suitable cross-linking agents, coupling agents and other additives, then melting and extruding them, then calendering or casting them.
What raw materials and additives are the main components of EVA photovoltaic film?
Generally, EVA manufacturers can achieve a thickness of 0.3-0.8mm. The more conventional specification is around 0.5mm. , but EVA Some of them are flat films, and some are embossed on both sides, if both sides are embossed, the difference in thickness when measured is about 0.5mm, it is that is to say that an film of 0.5mm will be 0.55mm when I measure it. a technician who produces EVA.
Photovoltaic film 1 square meter multiple
EVA is a copolymer of ethylene and vinyl acetate. It is the fourth largest polymer in the ethylene series after HDPE, LDPE and LLDPE. copolymer. In its molecular structure, the substituents are arranged irregularly on the molecular chain. At the same time, the asymmetric carbon atoms in the molecular chain have different configurations and irregular arrangements. It is therefore a less crystalline and polar material. flexibility. In addition, it has good wettability when heated and melted, and has good flexibility, stress crack resistance and bonding performance when cooled and solidified.
The properties of EVA mainly depend on its vinyl acetate (VA) content and its melt flow index (MI). When the VA contentincreases and MI remains unchanged, transparency increases and adhesion strength also increases, and corresponding properties such as crystallinity, hardness, softening point, stiffness, tensile strength, chemical resistance and resistance to thermal deformation are all the same. Decrease ; when the MI increases and the VA content remains unchanged, that is, the molecular weight of EVA decreases and the melt viscosity, toughness, tensile strength and strength to cracking under corresponding environmental stress all decrease. EVA used for solar cell packaging requires light transmission above 90% and good weather resistance. Currently, EVA materials with VA content of 26-33% are widely used.
Pure EVA itself is a linear polymer, a thermoplastic resin, and does not crosslink to forwed a three-dimensional network structure. Usually, when applying it as an encapsulating adhesive film, a certain amount of cross-linking agent and co-cross-linking agent must be added to cross-link the molecular chains together, thus making them thermosetting. The cross-linking and curing process during the encapsulation process consists of the peroxide cross-linker (RO-OM) decomposing into the free radicals RO· and MO·, triggering the combination of molecular branched vinyl acetate EVA (VA) to form a triple dimensional network structure, cross-linking and curing of EVA
Advantages, disadvantages and modifications of EVA encapsulation materials
Solar cell modules should generally be used normally for 25 to 30 years. , and since solar cell modules generally operate outdoors, so the environment is relatively harsh, the requirementss in terms of packaging materials are therefore more strict. EVA has transparent, soft, hot melt adhesive properties, low melting temperature and melting fluidity. Good characteristics, these characteristics meet the requirements of solar cell packaging materials. However, pure EVA has poor heat and humidity resistance and UV resistance, is prone to aging and yellowing, has poor cohesive force and poor creep resistance. This will affect the photoelectric conversion efficiency and lifespan of solar cells. to modify EVA to improve molecular structure and weather resistance. The main reason for the aging and yellowing of EVA film is that its molecular chain has a linear structure, composed of carbon-oxygen bonds, carbon-hydrogen bonds, etc. These chemical bonds will break, recombine or oxidize under conditionsmoist and external ions. alternating hot environments and under ultraviolet light irradiation, this produces chromophores, causing the EVA film to yellow and degrade. Current methods of modifying EVA mainly focus on adding cross-linking agents to cross-link it and adding some additives with functions such as antioxidant, UV absorption or stability to the light. The crosslinking agent is generally an organic peroxide. When the EVA film is heated to encapsulate the solar cells, it will be thermally decomposed to generate free radicals, which will trigger the EVA molecular chains to combine to form a network structure and increase the molecular force. stability. Added additives such as antioxidants, UV absorption or light stability can generally reduce the oxidative decomposition rate of EVA film, improve theanti-aging and UV performance and reduce the degree of yellowing. crosslinks in EVA sealant will also react chemically with these additives upon prolonged aging, causing bubbles and yellowing of the adhesive film during use.
The weight per square meter is between 100 and 200 grams. Photovoltaic film is a material used for solar panels. Its main function is to protect the panel surface and improve the photoelectric conversion efficiency of the panel. Depending on the thickness and material, the weight of the photovoltaic film varies. The weight of photovoltaic film is said to be between 0.1 and 0.2 kilograms, that is, the weight per square meter is between 100 and 200 grams. The specific weight must also be measured and calculated based on different products.