SIGMA – paint coats made in the USA (by PPG).
Wooden windows were covered with coat of alkyd polymers and flammable solvents until the 1980s. Such coats had serious disadvantages:
a) no elasticity, which resulted in their peeling off as a result of shearing forces on the contact surface of fixed paint and moving wood (changes of humidity). As a consequence, the paint coat had to be removed down to the wooden base and 3 to 5 new layers had to be applied for repair.
b) low resistance to ageing caused by external conditions (mainly UV radiation)
These disadvantages meant that the paint coats had to be renovated every 1-2 years.
Now we have new generation paint coats, with much better technical and utility parameters:
a) high elasticity which means that the paint coat moves with the wood; as a result, there is no peeling.
b) high resistance to ageing, which is a consequence of improved chemical composition and the painting technology:
- polyacryl and polyurethane (coat-forming components) are much more resistant to ageing than the older-type alkyl components.
- a set of pigments which provided the coat with the right colour, but it also increases its resistance to ageing caused by external conditions.
- proper anti-ageing (UV stabilisers).
- 2-step painting technique: commonly applied, this technique produces a durable coat and ensures sufficient protection of wood. Impregnating prime coat (immersion) plus a protective and decorative layer (hydrodynamic spraying) – GUARANTEE FOR UP TO 5 YEARS
- 4-step painting technique: very popular due to higher resistance of the paint to ageing, two additional layers, i.e. a deep-penetrating impregnate and a seal which fills micropores, smoothes out the coat texture and considerably reduces vapour permeation through the coat, sealing it sufficiently to be covered by a 7-YEAR GUARANTEE.
- cutting-edge nanovarnishes: which have made possible what could not have appeared in a professional product until recently... More at KARO.