Rus Articles Journal

What paints paints?

Colour of paints depend first of all on pigments. Pigments are the thinly crushed inorganic and organic substances of a certain color, insoluble in water solvents and the painted materials (unlike dyes which rastvorima).

From inorganic most often use pigments on the basis of oxides and insoluble salts of iron, zinc, chrome, lead, molybdenum.

Independently there is a dioxide of the titan. It it is dazzling white and, the main thing, does not change color over time. In combination with other pigments he allows to receive light paints practically of any color. It is also applied as the main pigment of the majority of white paints.

Metal pigments are the tonkoizmelchenny metal powders (aluminum, bronze powder) covered with a sheeting.

The quantity of organic pigments of the various nature are immeasurably higher, than inorganic. As a rule, it is the organic dyes transferred to an insoluble form. Carbon therefore it is easy to distinguish them from inorganic calcinating is a part of these substances. Under the influence of high temperature they char and blacken.

By the way, the soot which is formed at combustion of organic substances, for example, of gas in the conditions of a lack of oxygen, is the major black pigment.

There are also dyes of the mixed nature, so-called farblak - they are received sedimentation on an inorganic white substratum of organic dyes.

Properties of pigments characterize by many parameters, the main of which are the painting and covering abilities.

The painting ability is an ability of a pigment to render the color when mixing with a white pigment. Than it is more, those need a pigment for receiving coloring of the necessary tone less, and it can be replaced with cheaper filler partially.

The covering ability or covering ability are estimated as quantity of the paint coats necessary to cover contrast (it is black - white) a substrate i.e. to make invisible border between white and black. Covering ability of paints is varied over a wide range - from transparent (lessiruyushchy) to completely impenetrable (covering).

This property depends on a difference of indicators of a svetoprelomleniye of a pigment and filming agent. Than it is more, especially an ukryvist a pigment. The covering ability depends also on percentage and a subtlety of crushing of pigments.

At cheap materials this ability is, as a rule, lower, therefore, their expense above. Also it happens that more expensive paint possessing high covering ability costs to the consumer cheaper as it work requires less.

To emphasize advantage of expensive high-quality materials, their producers often specify on a label or the covering ability, or the approximate consumption of paint which is indirectly connected with it.

Covering ability and the painting ability are not always connected with each other. Inorganic pigments, as a rule, possess high covering ability, however brightness of their color concedes to organic.

Light resistance - ability of pigments to keep the color under the influence of a sunlight. On some pigments, most often, organic, destructively work ultraviolet rays fade, and they fade.

Many pigments change color and under the influence of high temperature. This circumstance should be considered when coloring systems of heating and thermal installations. In some cases paints with such pigments use as temperature indicators.]