Mixing Virgin and Recycled Raw Materials for Plastic Film Production

A shrewd selection of raw material characteristics and production processes is essential for the production of high-purity thermoplastic film.

Mixing polymers for the production of thermoplastic film

The production of film intended for food, optical grade or medical applications requires virgin – i.e., low-impurity – raw materials. Nevertheless, it is often necessary – and sometimes required by regulations in force – to provide for the use of mixed virgin materials and low-impurity recycled plastic in plastic extrusion processes.

Mixing virgin raw materials and recycled plastic – why?

Two major reasons underlie the mixing of virgin and recycled raw materials for the production of high-purity film:

• Production characteristics must comply with environment protection regulations in force; in particular, it is necessary to minimize the production of new plastics. This means a percentage of recycled plastic must be used. In the EU, the Packaging and Packaging Waste Regulation (Regulation (EU) 2025/40) sets minimum recycled content for plastic packaging from 2030.
• Although high-purity film would ideally use only virgin polymers, introducing a small percentage of recycled plastic helps control raw material costs.

Recycled material percentage

What is the optimized ratio in mixing virgin and recycled raw materials? When mixing virgin and recycled materials, mixing percentage sensibly varies and depends on the following:

• End applications
• End product intended use
• Required quality

High-quality thermoplastic film

In such a scenario, two key factors must be considered when selecting the recycled plastic material intended for a high-quality end product:

• Impurity level must be minimized – low impurity levels are essential for food and medical end applications.
• During extrusion cycle, a high-level filtration continuous screen changer is required. A remarkably high filtering capacity is essential whenever recycled raw materials are used, even if they have a low impurity content. Moreover, the screen changer must be continuous, i.e., it should offer an uninterrupted plastic film production.

Continuous screen changers offering high filtering capacity

Starting from a mix of virgin and low-impurity recycled raw materials, what is the filtering capacity suitable for plastic film production? Filtering capacity requirements mostly depend on end application purity level and should be suitable for end products. Cofit manufactures continuous and self-cleaning screen changers suitable for the production of high-quality thermoplastic film – BOPP and BOPET film included – by screening mixed virgin and recycled plastics. The Cofit AP Series, a continuous and self-cleaning double cartridge screen changer, offers filtration levels down to 3 µm – such filtration levels comply with quality requirements set by food, optical grade, or medical application standards.

Cofit AP screen changers

Cofit AP screen changers are continuous and self-cleaning: the operator activates the cleaning with a key, and a backflush of melt cleans the screen without stopping the line. They are built for high filtration, with operating pressures above 500 bar and melt pressure stable within ±2% during the cleaning cycle. The AP Series works without hydraulic systems and is designed for a long service life. Have a look at AP technical data sheet. Cofit designs and manufactures screen changers that keep the line running: the AP Series for clean and semi-clean polymer, including BOPP and BOPET film, and GorillaBelt and ScrapeAway for contaminated recycled melts. Request a Technical Alignment to see how a screen changer that keeps the line running can optimize your plastic extrusion process.