really strong colours

Architect's memo 84: September 2006

Tinting systems are a marketer's delight and the paint chemists' nightmare.

The benefits to the marketing fraternity are obvious - from a minimum number of stock units a full range of colours can be produced on demand. The concept of being 'out' of a colour and having to wait - sometimes several weeks - until the factory could schedule manufacture, are almost gone.

To make a colour from base pigments is a somewhat tricky and messy procedure but the paint produced from a relatively simple mixture of pigment and binder is often at an optimum for film properties.

Tinters, on the other hand, are intermediate products in which the pigments are dispersed into high levels of wetting agents; dispersing agents; stabilisers; humectants and water. These excipient materials are necessary to achieve stability of the pigment paste (tinter) and to achieve compatibility into the various paints they are added to but they play no useful role whatsoever in the final paint film. Indeed, they can be harmful, detracting from water and weather resistance.

To exacerbate the problem, many tinters are locked into old technology where dispersing techniques (especially for bright organic pigments) were not so well developed as they could be. This has meant that most of the well established tinters on the market have low levels of pigment and high levels of excipients. This further means that in order to achieve strong, bright shades, inordinate levels of tinter have to be added. Many times the shade cannot be reached without a significant compromise in hiding power.

Resene recognised this inherent weakness in typical tinting systems and decided to look 'outside the square' at what was available.

The first step was the world first concept of coloured tones which lead to a hybrid between factory made and fully tinted paints. Even this dramatic improvement was not considered enough and the search for new technologies went on. The underlying drive was to achieve higher and higher strength tinters so that less had to be added to achieve the desired shade and that the film properties could more closely approach the 'pure', factory manufactured shade.

Although the widely cast net landed a 'grab bag' of different technologies, they all delivered the desired higher strength. As Resene has taken over the design and manufacture of its own tinters, a continuous streamlining and improvement of technology has been put in place.

The other decision that Resene took was to look outside the typical offering of decorative pigments towards the higher performing automotive grades. Whilst both pigment lines can produce the same shades, tremendous differences in performance become very obvious on exposure to weathering.

This is particularly obvious in the area of bright yellows, oranges and reds.

New pigment developments are occurring all the time as are new pigment dispersants. These are constantly evaluated for utility in the tinting system. These may result in the improved performance of existing shades or, sometimes, the ability to enter a new colour space.

Resene has undertaken to advance its leadership in this area in the knowledge that, unless a competitor can produce a match to a Resene shade using the same strength colourants and exactly the same pigments,then really it is no match at all.

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