Traditional composite film rolls often combine different materials (such as PET/aluminum foil/PE), which poses difficulties for recycling and separation. Recyclable composite film rolls mainly achieve breakthroughs through the following approaches:
Mono-material structure: This is currently the most mainstream approach. Taking the all-PE structure as an example, the outer layer is made of biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE) to replace the traditional outer layers of BOPP or BOPET. These PE films, after the stretching process, have significantly improved transparency, stiffness, and strength, making them suitable for outer packaging. The inner layer uses non-stretched PE (such as LDPE or LLDPE) to provide good heat-sealing performance. Since all the film-forming materials are polyethylene, they are highly compatible and can be recycled as a whole without separation. The all-polypropylene (PP) structure follows a similar principle.
Innovative barrier coating: To endow high barrier properties on a single-material basis, a special barrier layer is coated on the base film. For instance, a coating solution composed of polyvinyl alcohol (PVA) and its alloys can form an excellent oxygen and water barrier layer. This coating is highly compatible with plastic substrates (such as PE or PP) and does not affect the overall recycling stream.
Biodegradable separation layer: This is a highly ingenious design. In composite films, a biodegradable polymer (such as modified poly(ε-caprolactone)) is used as one of the layers. When the packaging is discarded, under specific conditions, this layer will degrade first, causing the layers of the composite film to separate automatically, facilitating subsequent sorting and recycling.
Recyclable composite roll films are gradually being applied in multiple fields:
Food and household product packaging: For instance, the packaging of dry foods such as candies and snacks has begun to adopt composite roll films with full PE structure. Some packaging for liquid foods are also exploring the use of single-material films with high barrier coating. The packaging of daily chemical products such as shampoo and detergent is also an important application scenario.
High-end and specialized fields: For example, nano-scale biological fiber composite films, due to their degradable, recyclable and controllable properties (such as mechanical strength and thermal conductivity), have shown potential in precision device packaging, luxury product packaging and flexible electronics.
When introducing recyclable composite roll films, there are several factors that need to be comprehensively considered:
Performance compatibility: It is necessary to confirm whether the barrier performance, mechanical strength, etc. of the new material meet the protection requirements of the product.
Cost factor: The initial cost of new environmentally friendly materials or processes may be relatively high.
Recycling infrastructure: Ensure that the recycling system in the area where the product is sold can handle the corresponding type of recyclable composite film.
