Mechanical recycling

The first aim of VinylPlus is to stimulate mechanical recycling, taking into account the quality of the waste collected and the requirements of further processing methods and of the final products.

These techniques separate a mixed or difficult waste stream into streams which can be handled by conventional mechanical recycling.

Neidhardt Recycling GmbH (DE): The input material is a PVC-aluminium composite used for blister packaging. The composite, which is supplied as a clean stream, is shredded down to 20 mm pieces. The shredded waste is transported by a conveyor belt to the acceleration rotor and ends up in the air stream between the rotor and the stator.

Aluminium and PVC are separated (delaminated) thanks to the high-rotation speed. The process transforms the aluminium sheet into balls, whereas the PVC sheet remains flat.

The delaminated mixture is then sieved, yielding fractions with well-defined granulometry of <0.5mm, 0.5-0.7mm, 0.7-1.0mm. Aluminium and PVC are then separated by an electrostatic device. The PVC fraction is supplied to PVC converters manufacturing products such as pipes, separators, etc. The aluminium is also recycled into foundries or for special applications.

R-Inversatech: This Japanese technology separates fibres from PVC waste such end-of-life as tarpaulins, using a high-speed beating technique. The fibres can be used in thermal and/or acoustic insulation. The PVC granulate is used in a broad range of flexible PVC applications.

FG Kunststoffmatten produces plastic mats for greenhouse flooring from recycled PVC composite films, plasticised films and coated fabrics. The mats have drainage holes allowing the plants to be watered from below. The remaining water is then drained away leaving a clean surface. The added heat insulation prevents plants from freezing in their containers. The flooring is suitable for driving on with small machines and it is easy to clean.

Caretta: Hemawe/Caretta has developed its own equipment and technique for separating fabric and tissue, etc. from soft PVC foils. Recyclable materials clad with fleece, fabric or textiles are transferred into a shredder and chopped into sections approximately 4-6 cm long. The shredded pieces are then granulated and sieved to separate the fibres. The PVC is used to manufacture damp-proof courses, sound-absorbing foils and soundproof mats for pipe insulation.

This includes mechanical recycling with some added features used in, for example, the production of large objects from mixed plastic waste. The mixed plastic waste is processed using conventional techniques (e.g. extrusion, moulding) into thick-walled objects such as shoe soles and urban furniture (e.g. park benches), traffic controllers and signallers, etc. Thick walls are required because the mix usually yields poor mechanical properties.

AgPR flooring recycling process: The AgPR cryogenic grinding recycling plant was built in 1993 and production started in 1994. Its production capacity is around 4,000 tonnes per year.

Rubber Research Elastomerics: In the USA, this firm uses a patented technology to mix PVC waste (tarpaulins and cable scrap) with shredded tyre scrap combined with a rubber compatibiliser. 50/50 blends produce hard products and can be used to replace timber in certain construction applications.

Light concrete: PVC waste is mixed into concrete to decrease its density. Such ‘light concrete’ is currently manufactured using polystyrene. Applications include non-structural elements like roofs, insulation walls and slabs covering gutters. 

Wood PVC composites: Plastic-wood composites are gaining a share of the decking market. Some firms are investigating new applications, for example, structural wood lumber and cladding. In the US some companies claims that their decking is manufactured from 95% recycled content, including reclaimed wood, sawdust and plastics. PVC has been tested along with other plastics such as PE and PP.

Compared to conventional mechanical recycling, non-conventional mechanical recycling methods are often more complex and have been developed to tackle PVC products that are more difficult to recycle. These materials are often composite materials or too contaminated to be accessible using conventional recycling. Examples of such waste streams include PVC cables where PVC could be contaminated with copper, or tarpaulins in which PVC is combined with polyester fibre.

An interesting solution is the Polyloop process for regenerating composite PVC in an easy-to-use container, adapted to the needs of industry, for the treatment of their post-industrial or post-consumer waste.

Polyloop is developing a process for regeneration of PVC based composites without depolymerisation thanks to a tested and approved selective dissolution process. It confirms its ability to reach a high recycling yield on the energy consumption and raw material value. Furthermore, this technology uses ‘Batch’ process that ensures strict traceability of recycled material.

The compact equipment, plug and play into an industrial plastic transformation site, allows the direct reuse of regenerated materials at the users’ site.

The Polyloop solution decentralises the recycling function and promotes the emergence of a multi-stakeholder ecosystem in a circular economy at a local level.

Circular EconomyRecycling optionsMechanical recycling