EVA Film Making Machine

GWELL develops a new type of EVA Film Making Machine with high output. It is co-extruded by two  extruders, with a line speed of 2x13m/min, an automatic winder, and a typical developed stress relief device, which can effectively eliminate the film. Residual stress generated during stretching or other production processes can solve the problem of heat shrinkage of EVA film, and the unique low-temperature extrusion design ensures that materials are fully mixed and plasticized.

Features of EVA Film Making Machine

• Excellent durability such as weather resistance, high-temperature resistance, humidity resistance, and ultraviolet resistance.
• It has excellent additional force on glass, metal, plastic PET, and TPT, and maintains long-term additional force.
• Excellent light-absorbing rate and transparency.
• Solar cells are deactivated and harmless during processing.
• High cross-linking rate after lamination.
•  Good encapsulation performance.

Technical parameter

1. Applicable materials: EVA+auxiliary for solar encapsulation film, POE+auxiliary
2.  The production line width of silver cylinder: 3000mm
3.  Die width: one pair of 2600mm; one pair of 3000mm (can be customized according to customer requirements, and the product can be cut into multiple pieces online according to requirements)
4. Product weight: 300-530g/m2
5. Extruder direction: from back to front (easy to disengage production debugging)
6.  Production line speed: s20m/min (actual production speed depends on raw material process and working conditions)
7. Thickness deviation: T Ds 3%, MDS 2%
8. Installed capacity: about 550kw (working capacity about 300kw)
9. Water supply temperature 7-20°C, water pressure 4-6bar, circulating water volume 40-50m3/h
10. Supply air source pressure z7bar air pressure 0.9 m3

Features of EVA Film-Making Machine

• According to the needs of customers, it can be customized in a variety of ways: single screw, multi-screw, parallel twin-screw, double-stage machine, etc. The raw material modification equipment can shorten the supply chain and save costs for customers.
• Combined control thickness measurement/automatic thickness measurement provides a guarantee for high-quality production and establishes a three-dimensional map of products through networking with defect detection, so as to analyze and predict problems intuitively and quickly. High-precision intelligent control maximizes the stability of the production line, and at the same time efficiently and scientifically assists in the establishment of the production process, and quickly forms data analysis to escort production.
• The latest far-infrared tempering process, precise temperature control, stainless steel, and special insulation materials to achieve heat preservation and energy saving. Online scrap recycling technology saves the cost to the greatest extent for customers.
• Mature EVA Film Making Machine equipment solutions, optimal shrinkage rate, minimum grammage error, fast machine adjustment response, and intelligent control to establish an all-around control system for product quality.
• Provide on-site layout and public works solutions, and provide customers with a full set of engineering support and one-stop solution to customers’ project construction problems.

What is EVA

EVA is an ethylene-vinyl acetate copolymer, which is produced by the copolymerization of ethylene (E) and vinyl acetate (VA) and is referred to as EVA, or E/VAC. Compared with polyethylene, EVA has reduced crystallinity and improved flexibility, impact resistance, filler compatibility, and heat sealing performance due to the introduction of vinyl acetate monomer in the molecular chain. Generally speaking, the performance of EVA resin mainly depends on the content of vinyl acetate on the molecular chain. Because the composition ratio can be adjusted to meet different application needs, the higher the content of vinyl acetate (VA content), its transparency, softness and toughness will be relatively improved.

EVA characteristics

1. Durability

Premium EVA film is known for its outstanding durability, even under harsh weather conditions such as high temperature and high humidity.

2. Bonding

Under the right conditions, EVA film has excellent adhesion to solar glass (not standard glass, which has a rough surface). EVA also bonds very well to the backsheet.

3. Optical

EVA is known for its excellent transparency. This means that light transmission is acceptable and doesn’t block too much sunlight trying to reach the solar cell. Today, several manufacturers in Asia use transparent backing, so there is transparency between the cells. This type of module is called a translucent module.

 What is EVA film

In the solar industry, the most common encapsulation is the use of cross-linkable ethylene vinyl acetate (EVA). With the help of a laminator, the cells are laminated between EVA films in a vacuum, in compression. The process takes place at temperatures up to 150 °C. One of the disadvantages of EVA film is that it is not UV resistant, so a protective front glass is required to shield it from UV rays.

Polymerization methods include high-pressure bulk polymerization (for plastics), solution polymerization (PVC processing aid), emulsion polymerization (adhesive), and suspension polymerization. Emulsion polymerization is used for vinyl acetate (VA) content higher than 30%, and high-pressure bulk polymerization is used for low vinyl acetate content.

The EVA Film Making Machine extrusion production line uses EVA resin (VA content 30-33%) as the base material to produce EVA film for solar photovoltaic cells. This production line can also produce hot-melt adhesive EVA interlayer film by changing the formula and process.