Лако-красочные материалы — производство

Pigmentation of a coating, in general, can be carried out by one of two processes. The first involves the use of a tint base scheme, where the mill base vehicle is either universal to the tint base scheme, or the final coating resin. In the case of the universal tint base, it is critical that the mill base vehicle is compatible with the coating resin, to eliminate the possibility of flocculation. Alternatively, different pigments can be blended together and ground in the base vehicle to the required fineness of grind. There has been a trend towards using commercial or in-house tint base schemes due to an overall improvement in manufacturing efficiency and the greater flexibility it provides to enable the paint manufacturer to supply a large range of colours.

Care is required with pigment selection due to the possibility of interaction of certain pigments with reactive groups in the resin. A variety of adverse reactions have been observed:

a) the interaction of acid functional resins, carboxylic acrylics with highly basic anti-corrosive pigments, resulting in storage instability and gelation

b) the interaction of resin functionality with certain coloured organic pigments resulting in immediate or time dependent colour changes.

c) the interaction of acidic pigments and extenders with commercially available resins from Michael reaction chemistry resulting in decreased reactivity * 9

It is recommended that the formulator carefully evaluates the effect of the interaction between the pigment and the functionality of the non-isocyanate acrylic vehicle before finalising the paint formulation.