Inorganic pigments - STS Group Chemical

Inorganic pigments

Inorganic pigments (pigment) is a material that changes the color of reflected or transmitted light as a result of selective absorption along the wavelength.

This physical process differs from fluorescence, phosphorescence and other forms of luminescence in that the pigment does not emit light.

Most materials selectively absorb light of a specific wavelength. The materials that people have selected and developed for use as pigments usually have special properties that make them useful for coloring other materials.

The pigment should have high tinting strength compared to the materials that it paints.

It must be stable in solid form at ambient temperature.

For industrial applications, the main property is constancy and color stability.

Pigments that are not permanent are called fluent.

Volatile pigments disappear with time, and some blacken under the influence of light.

Pigments are used for coloring paints, inks, plastics, fabrics, cosmetics, food and other materials.

Most of the pigments used in production and in the visual arts are dry dyes, usually ground into fine powder.

For use in paint, this powder is added to a binder, a relatively neutral or colorless material that suspends the pigment and gives the paint adhesion.

A distinction is usually made between a pigment that is insoluble in its carrier and a dye that is either liquid in itself or soluble in its carrier.

The dye may act as a pigment or as a dye, depending on the carrier used.

In some cases, the pigment may be made from a dye by precipitation of a soluble dye with a metal salt. The resulting pigment is called lake pigment.

The term biological pigment is used for all colored substances, regardless of their solubility.

The introduction of pigments in paints and varnishes is the main method for regulating the decorative properties of coatings – color and opacity (hiding power).

The pigment gives opacity to the pigmented material in the event that its refractive index is higher than the refractive index of the film former. The greater the difference in refractive indices of the pigment and film former, the greater the opacity of such a pigmented material. In addition, the shape of the pigment particles is important, for example, the lamellar shape of the pigment particles gives a greater hiding power than a needle or spherical one.

The introduction of pigments and fillers allows you to adjust other important properties of composite materials – deformation-strength, insulating, anti-corrosion, adhesive strength, as well as to obtain coatings with special properties – electrically conductive, electrically insulating, heat-resistant, fire retardant, etc.

Pigment properties

The chemical properties of the pigment directly depend on its composition.

High quality pigment must meet the following parameters:

– the pigment should not fade when exposed to water or another organic solvent

– must be resistant to alkalis, because in water-dispersed products an increased level of PH

– does not change properties under the influence of high temperatures

– does not enter into any chemical reactions with any component of the paint composition

Photochemical activity of pigments

By photochemical activity is meant the activity of a pigment, which is capable of destroying a film-forming layer of paint, using a redox process.

The pigment has a similar effect due to the ability to convert absorbed light rays into energy. All this negatively affects the condition of the coloring product. The phenomenon of photochemical activity can change the chemical composition of the pigment, its crystalline structure. Because of this, the durability of the coating can be significantly reduced.

It is impossible to completely exclude such a chemical reaction. To minimize the damage caused by the oxidation of the pigment, various modifying compounds, for example, zinc, aluminum, magnesium and other heavy metals, are added to its composition.

Inorganic pigments

The most numerous group of pigments is inorganic pigments. Externally, the inorganic pigment looks like a colored powder. This pigment is poorly soluble in water. The pigment is obtained from mineral raw materials, clay, limestone. In the production of pigments using temperature and chemical treatment.

The quality of the inorganic pigment is determined by its properties.

Among the basic requirements, inorganic pigment should:

have good hiding power
completely overlap the color of the unpainted surface
pigment should prevent surface corrosion
alkali and acids should not dissolve the pigment or violate its integrity

There is a huge classification system for inorganic pigments. They are divided by scope, chemical composition, purpose, etc.

Among such a huge number of subspecies, there are three main groups of pigments:

pigments that are extracted from ores and clays by dehydration
limestone, minerals and gypsum are used to produce mineral pigments
Synthetic pigments are obtained by chemical treatment of various metals.

Today, technology does not stand still. Scientists have invented new inorganic pigments that have unique properties. New pigments are able to withstand temperatures up to 400 ° C, are not exposed to sunlight, have a high color content, do not contain dangerous toxins.

STS Group imports pigments from China, India, Iran and Korea.

The goods are delivered from the manufacturer’s warehouse or from our warehouse in Moscow by any means of transport as soon as possible to any region of Russia and the CIS countries.

Our products are certified according to all Russian requirements and standards.