Colour Matching

When our laboratory receives a colour match request we first have to select the pigments and dyestuffs used based on the following customer selected criteria:

• Heat Stability
• Compatibility with requested polymer
• Light fastness
• Toxicity
• Reliable pigment combinations
• Metamerism
• Cost

Once the pigments have been selected a labshot is made in the lab using the requested base polymer. The pigments, polymers and dispersants are mixed and then injection moulded to produce a colour plaque. If the colourist is not satisfied, the process is repeated with adjustments until a satisfactory result is achieved.

A record of results is created and an SCM Number (Broadway Colour Match Number) is assigned.

The labshot is then converted into a masterbatch formula dependant on the customers requested addition rate (let down %). This may be adjusted if there is a high loading of pigment involved. A sample is then made under production conditions to ensure future consistency. The sample is then let down in the appropriate polymer and moulded into colour plaques which are compared back to the labshot. If the results are unsatisfactory adjustments are made as necessary.

If satisfactory some of the masterbatch sample and plaques are retained with the rest being sent to the customer (usually 1kg and 6 plaques) so both have a record of the match.

If the customer approves the match then the sample becomes the 'master standard' to which all future production is referred. The product is then given a production number. This consists of a two-letter material reference, a four-digit approval code, a two-letter colour reference and the let down rate. E.g. SP2352/BL/5

This indicates a polypropylene masterbatch (SP), with (2352) indicating its approval number. The (BL) code indicates that it is blue in colour and the (5) shows that it is at 5% let down.