NEGOTIATING THE COLOURANTS MINEFIELD
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Colouring plastics is becoming increasingly complex. With mounting EU legislation controlling the use of pigments and additives, choosing the correct colour to meet legal and application requirements as well as optimum cost is both critical and complicated.
In some instances it is mandatory to use certain pigments while for other applications lower cost alternatives are acceptable. Get it wrong and the end product might not be fit for purpose or, worse still, illegal. Either way the directives present problems for end users, processors, compounders and masterbatch manufacturers, says Tony Gaukroger of Colour Tone Masterbatch Limited.
Although designed to protect consumers or the environment, the problems lie in interpretation of the directives which can easily lead to confusion. It’s a minefield for manufacturers. For example, the use of chrome yellow to colour a PP beach bat would be illegal if the product was classified as a toy. If defined as sports equipment this pigment would be acceptable. A nylon moulding coloured with food approved cadmium yellow would be perfectly acceptable in a food processing product as long as it did not conflict with rules on the use of colours in electrical appliances.
As one of the aims of the legislation is to promote recycling, manufacturers have to ensure they use colourants that are acceptable. The chrome yellow pigment mentioned earlier could not, for example, be used in electrical, automotive or packaging applications because it would offend recycling conventions.
A situation where plastic components have to be classified either as packaging or part of a product is not as simple as it sounds. Is a video cassette box (library case) packaging or is it a product? When it comes to disposal is a ‘grow bag’ packaging or an intrinsic part of the product?
According to Tony Gaukroger, processors and end users can protect themselves by taking a number of precautions. “A system that will enable them to keep up to date with current and future legislation is essential. Additionally, it’s important to track developments with suppliers and professional bodies such as the British Plastics Federation and the Trading Standards Office. Critically, all the companies in the product and manufacturing chain should implement a process that allows them to accurately classify the end use of the items they intend to manufacture.
“Masterbatch companies in particular have to know the intended use of products so they can create cost competitive formulations that comply. One of the aims of ISO 9001:2000 accreditation is to ensure we all make products that are legal and fit for purpose. EU legislation which is ambiguous simply makes the task more difficult. And remember, the rules don’t just apply to new colours. So don’t be tempted to use old stocks of universal masterbatches without talking to someone who’s up to speed on the subject.”
ColourTone Masterbatch Limited
Pant Glas Farm Industrial Estate
Telephone: 01222 888910
Fax: 01222 868487
Genie Kenraw Ltd. Telephone 01277 633828 www.geniekenraw.co.uk
Telephone: 01428 723211
Fax: 01428 722371