The primary importance of impregnation is shown in the old or older wall surfaces, where the reasons for the application are the following: number of old coatings, because of which the adhesion of the new coating is unreliable, a surface poor with binder, which also leads to lower adhesion of the new coating, uneven quality of the entire surface due to repair of cracks, levelling with the materials which are in composition not the same as the basis ... The impregnation cures the substrate, binds old coats between them and with a substrate, unifies and reduces the permeability and improves the adhesion of new coats, reduces also the quantity of the needed paint and colour shade is even. Especially important is the role of impregnation from point of view of adhesion at the application of high quality coatings to substrate, which was beforehand painted with coats of worse quality.
In general, impregnations are divided into four groups:
An important composition of impregnation is always a binder, solved in a solvent or in the form of water dispersion. Normally, in the field of water-based coats the impregnations have the similar composition as the coatings. There are acrylic, silicone, silicate impregnations, corresponding to dispersion acrylic, silicone and silacate paints. In solvent-based coatings a synthetic resin is dissolved in an organic solvent. The major difference between water and solvent impregnation is the form in which the binder is. In the water impregnations the binder in the form of particles is distributed in the water, so it is very important that the particles are minimized because the binder particles may penetrate deep into the ground.
For porous, chalked and very permeable substrates we use transparent impregnation for smooth, firm and badly permeable a pigmented impregnation. Pigmented impregnation is used when we want to achieve uniformity of absorption, partial colouring and unifiying of the top colour shade. Often the substrate has a different permeability and we do not unify it enough with a transparent impregnation, therefore it often happens, with yellow, red, orange colour shades (with bad hiding power) that the coating appearance is bad – the problem is that colour shade is not even on complete surface. The selection between solvent-based and water-based impregnation depends much on characteristics or substrate quality. On general it is valid that solvent-based impregnation is used with chalked and very smooth surfaces, due to solvent basis we avoid interior wall surfaces due to ecologic and health reasons. With facade paints and facade thermoisolation systems the correct impregnation selection is very important for the desired coat characteristics, especially the system vapour permeability. Therefore we recommend with silicone facade paints and silicone plasters use of SPEKTRA silicone impregnation, as it is by binder composition similar to coat and keeps the system vapour permeability. It is also important that we know the composition of heat-isolation system. If for isolation styropore is used, we may not use impregnations on basis of solvents at renovations, as they could cause dissolving of styropore. With silicate coats the silicate impregnation is obligatory, as due to specific curing (silicification) it must not reduce reaction of water glass with silicates in substrate. At Helios we help you with selection of the right impregnation with published systems, from which the correct use of basic,intermediate and top coats is evident. The systems are due to complexity of substrates and the coat characteristics at each coat also stated in technical data sheets.
Helios offers under the trademark SPEKTRA the following impregnations:
SPEKTRA acrylic impregnation, is on water basis, binder particles are approx. three times smaller from binder particles in paints. It is suitable for facade and interior wall surfaces. Prior to use thin it with water: 1 to 3 parts of water on 1 part of impregnation.
SPEKTRA acrylic impregnation concentrate is a high concentrated impregnation on water basis, which enables universal use for differently permeable substrates, suitable for facade and interior wall surfaces. Prior to use thin it with water: 1 to 5 parts of water to 1 part of impregnation.
SPEKTRA deep impregnation, on basis of solvents, for especially demanding, intensively chalked, bad porous surfaces, such as concrete. The impregnation will not be thinned.
SPEKTRA silicone impregnation, on basis of silicone resin in the system with silicone facade paint. Prior to use it is thinned with water in ratio 1:1.
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