Injection Moulding and the Environment
Rutland Plastics answers some of the most commonly asked questions about the environmental considerations within injection moulding.
Q) How 'Green' are injection moulded parts?
A) Environmental considerations are becoming increasingly important when designing injection moulded parts. There are two aspects – the green credentials of the polymer being used and the end of life recyclability of the product.
Q) Are there polymers that are more environmentally friendly?
A) You can use reprocessed plastic. The majority of reprocessed material is recovered from plastic scrap and is the purest form of plastic as it is normally well sorted, clean and dry. Domestic waste and end of life reclaim are often dirty, wet and of mixed types. This makes recycling more difficult and costly although there are now some very innovative plants dealing with this type of waste in a cost effective way.
The scrap is sometimes blended with some virgin polymer to produce a reprocessed grade with the required properties. A wide range of reprocessed polymers is available although colours are limited.
Q) Are there any plastics not derived from oil?
A) There are an increasing number of Bioplastics being developed. These are produced from renewable sources that are generally plant based. At the moment there is a limited choice of polymers for injection moulding but this is an area of future growth. Potentially 90% of polymers could be replaced by bio-based equivalents.
Q) What do I need to consider for my product to be easily recyclable?
A) Although functionality is still the primary consideration, designers now have a responsibility to design with economic use of materials and end of life recyclability in mind. Whenever recycling parts it is desirable to just be able to discard them without any further action, any dismantling and sorting of components should be minimised. Where possible make components from the same material. If parts need joining, avoid threaded inserts if possible.
One alternative is the use of snap-fits wherever practical. If any form of bonding is required, polyester and polyurethane adhesives should be avoided. Also try not to use decorative paints, lacquers and protective coatings. When printing or using some other form of decoration, use easy to remove secondary mouldings as the base.
Rutland Plastics has the Environmental Management Standard ISO14001:2004.
