Modern paints are complex, multi-component structures - the composition of which is selected depending on the type of surface and weather conditions which this surface experiences. The common components for the majority of paints are: filling compounds, film-forming substances, solvents, softeners, pigments and desiccants.

The name of paint (alkyd, oil-based, latex) is given to it according to the film-forming components it contains.  These components are substances which create a film that sticks to the surface. The speed of drying and coating strength depend on the properties of these components.

Pigments, fine powders added to the composition of the paint, provide colour for the paint. Pigments may be either artificial or natural. Artificial pigments are titanium dioxide - white pigment (paints containing this component are usually marked as ‘super white’, ‘high spreading capacity’), iron minium - red pigment, oil azure, blue cobalt (blue pigment, stable to the influence of high temperatures and alkalis), green rouge - dark green pigment. Filling compound is a mineral matter added to the paint to increase body residue. Ordinary chalk is frequently used as a filling compound.

Due to the presence of solvents in the composition of paint, it gains viscosity and covers the substrate smoothly. Softeners are added to decrease the viscosity of paint and to give elasticity to the coating. Desiccants are catalysts which accelerate drying of paint, very often manganese or cobalt salt is used for this purpose.

Having examined the label on the can of paint, you will certainly notice two important characteristics of paint: spreading capacity and luster. The capacity of coating the surface is called spreading capacity. This parameter depends on such characteristics of the pigment as form, colour and size of its particles. It is expressed in the grammes of the paint necessary to cover one sq metre of the surface. Luster is the capacity of the surface to reflect light. It is designated by means of marks: M - matte, HM – half-matte, DM - deeply matte.

 

The main difference of water-dispersive paints lies in the fact that the components included in their composition are dispersed in a water solution, instead of being dissolved in toxic solvents. To prevent setting-out of pigments, emulsifying agents and stabilizers are added to the composition of such paints. Water-dispersive paints are non-toxic, they are diluted by water and dry quickly. They can be used to coat concrete, wooden and stone surfaces. It is especially effective to apply this kind of paints to porous surfaces: water from the paint is partly absorbed into the substrate and  partly vaporized, so that the surface ‘breathes’ after coloring. It is necessary to remember, that water-dispersive paints on the base of polyvinyl acetate (P.V.A.) are not waterproof. For painting facades and other surfaces subject to the influence of water they apply acrylate and styrenebutadien paints. The surface coated with acrylate paint can be easily washed and cleaned.

 

Enamels are made on the base of varnishes: dry pigments are grinded with varnishes. This kind of paint is used to coat metal, fabric and plastered surfaces. Varnishes are made on the base of resins dissolved in volatile solvent which evaporates after laying the varnish and leaves a film on the varnished surface. The name of the varnish is determined by the kind of film-forming substance or the kind of solvent. They distinguish oil, alcohol, alkyd, polyurethane, epoxy, bituminous, coal varnishes and nitrate dope. All of them are used to create enamels. The type of the varnish determines properties (spreading capacity, time of drying) of the enamel made on the base of it. For example, nitrate dope is quick-drying, so nitroenamel paints dry up quickly.

 

This type of paint is represented by calcic paints which consist of lime milk and pigments, resistant to the influence of alkalis. The durability of the such paint coating is determined by carbonization of lime - the process occuring in the open air under certain conditions. Therefore it is recommended to use calcic paints in cool weather and to humidify the surface you are going to paint beforehand. Calcic paints are used mainly for painting facades.

One more kind of mineral paint is water-cement paint, it is made on the base of pigmented cements and colour clincer cements. Two layers of paint are applied and the surface should be humidified. Water-cement paints are used for exterior finish of concrete, brick and plastered surfaces.