WHAT IS PAINT ?

All objects are vulnerable at their surface. It is the surface of any article that makes contact with the corroding ( or oxidising) air. The surface of objects left in the open bare the burnt of the sun, rain, fog, dew, ice and snow. Under these conditions iron rusts, wood rots ( or shrinks and cracks) and road surfaces crack and disintegrate.

Other surfaces suffer the wear of daily use, scratches, dents and abrasions at their surface. To minimise the damage, man applies to these surfaces varios caotings designed to protect them. Coatings can also be used to decorate the article, to add colour and lustre and to smooth out any roughness or irregularities caused bu the manufacturing process. Thus, the fuction of any surface coating is towfold, to protect and decorate. Other feature include identification, logos and signs, communication and hazard warnings.

There are many surfaces caotings that do this; wallpaper, plastic sheeting, chrome and silver plating. No coating material is more versatile than paints, which can be applied to any surfaces, however awkward its shape or size, by one process or another.

Paint is a lossely used word coveringa whole variety of materials; enamels, lacquers, varnishes, undercoats, surfaces, primers, sealers, fillers, stoppers and many other.

It is essential to grasp at once that these and less obviously related products, such as plaster, concrete, tar and adhesive ara all formulated on the same basic principles and contain some or all the three main ingredients.

First, a pigment may be included. Pigments have both decorative and protective properties. The simplest form of paint is whitewash and when dry, whitewash is nothing more than a pigment-whiting (calcium carbonate), spread over a surface. It decorates and to some extent protects, but it rubs off. So most paints contain a second ingredient, a resin polymer (film former or binder), to bind together the pigment particles and hold them to the surface. If the pigment is left out, the film former covers and protects the surface, decorating it by giving it gloss or sheen.

It is difficult to attach coatings that are not fluid to any but the simplest of surfaces. The fluidity of paitn permits penetration to the most intricate crevices. This is achieved by dissolving the film former in a solvent or by colloidal suspension (emulsion) of both pigment and film former in a diluent.

Thus, the third basic ingredient of the paint is a liqid. Often the film former/liquid mix is called the vehicle for the pigment.