From production to application: analysis of the complete industry chain of EVA transparent film
1. Raw materials and production process of EVA transparent film
(1) Raw material composition
The main components of EVA transparent film include:
Ethylene: a product of petroleum cracking, which determines the basic structure of the film.
Vinyl acetate (VA): provides flexibility and viscosity, and the content is usually 5%-40%.
Additives: such as UV inhibitors, antioxidants, cross-linking agents, etc., used to enhance performance.
(2) Core production process
The production process of EVA transparent film mainly includes the following steps:
① Polymerization reaction
Ethylene and vinyl acetate are polymerized in a high-pressure reactor to form EVA resin particles. The higher the VA content, the stronger the flexibility and viscosity of the film.
② Extrusion molding
EVA resin is melt-extruded and made into a film by cast or blow molding.
Cast method: produces films with high transparency and uniform thickness, suitable for photovoltaic module encapsulation.
Blow molding: low cost, suitable for packaging and other fields.
③ Cross-linking treatment (optional)
Some EVA films need to be irradiated or chemically cross-linked to improve heat resistance and mechanical strength (such as EVA films for photovoltaics).
④ Slitting and packaging
Cut into different specifications according to customer needs and carry out dust-proof and moisture-proof packaging.
2. Main application areas of EVA transparent film
(1) Photovoltaic industry (core application)
Function: As the encapsulation material of solar panels, it protects the cells and enhances light transmittance.
Requirements: high light transmittance (>90%), anti-UV aging, high temperature resistance (-40℃~85℃).
(2) Packaging industry
Food packaging: used for fresh food tray coating to prevent oxidation and moisture loss.
Electronic product packaging: cushioning and shockproof, transparent and visible.
(3) Construction industry
Glass interlayer film: enhance the impact resistance of safety glass.
Greenhouse film: light-transmitting and heat-insulating, strong weather resistance.
(4) Medical field
Medical dressing: breathable, soft, suitable for wound dressing.
Drug packaging: prevent drugs from getting damp and deteriorating.
Although EVA transparent film is thin, it plays an irreplaceable role in new energy, packaging, construction and other fields. With the expansion of the photovoltaic industry and the increase in environmental protection needs, the EVA film market will continue to grow. Chinese companies are accelerating technological breakthroughs and are expected to occupy a more core position in the global industrial chain in the future.
