Manufacturing solvent-free solid paint

It is difficult to manufacture small quantities of solid paint efficiently and quickly. The reason for this is that solid paint cannot readily be manufactured by the conventional route that is often used for small quantities of solvent-based and water-based paints. These liquid coatings often make use of bases or tinters to allow small quantities to be made quickly, hand-painted oil painting efficiently, with low loss, and at low cost. Until now, this manufacturing technique has not been available for solid paint.

As a consequence, conventionally, solid paint is manufactured in small batches on apparatus that is designed for large batches, with the result that there are long equipment clean-up times at colour changeovers and proportionally large losses of paint at such changeovers. One attempt to overcome the difficulty of manufacturing small quantities of solid paint efficiently and quickly involves grinding powdered paint to a very small particle size and combining the powdered paint with coloured powders and agglomerating the mixed powders to produce a paint with the required visual colour.

This is described in Australian patent 643191. Oil Paintings This proposal suffers from the disadvantage of considerable expense of grinding powdered paint to very small particle sizes and thereafter agglomerating mixtures of ground powdered paint and coloured powders to required product size. In addition, processing solid paints that are thermosetting paints in accordance with this proposal is especially difficult since thermosetting paints are liable to change chemically if the processing temperature exceeds the cross-linking temperature of the paints. This is a significant issue since solid paints are usually thermosetting paints. (article source:Oil Painting)