Video: Water-based Paints
Water-based paints (or water-borne, or latex, as they are sometimes called) are among the most economical and easy to apply products. The share of their consumption, according to various estimates, ranges from 30% to 80%. In interiors, they are mainly used for painting walls and ceilings.
Water-dispersion compositions do not contain organic solvents, so they are practically odorless and environmentally friendly. They can be applied by brush, roller or spray. The resulting coating has high adhesion to almost all substrates and has high performance characteristics.
In water-dispersion paints and varnishes, binder particles are dispersed in water. In the process of evaporation of water, they approach each other and when contact occurs, they stick to each other, forming a film.
These products are usually produced in white.
To obtain the desired color or shade (the nomenclature is practically unlimited), materials are tinted. To do this, use special toning dyes that allow you to achieve the desired shade. Pigments have even been developed to imitate gold, silver, platinum, steel or bronze.
The paint can be tinted by hand directly at the construction site. However, firstly, it is difficult to obtain the required shade, and secondly, it will practically not be possible to repeat it if the need arises. Therefore, the modern method is to use special equipment (tinting machines), which allow not only to obtain any amount of paint of the desired color, but also to repeat it if necessary. To select the desired shade, almost all the world's leading paint manufacturers have their own tinting cards, where each shade is assigned its own number.
As a rule, water-dispersible materials lose their properties when frozen, therefore, in cold weather, they must be stored in heated rooms.
The properties of water-dispersible paints and varnishes depend on which polymers were used as a binder. PVA-based paints have low water resistance and therefore have a rather narrow field of application. This is the painting of ceilings and interior walls in dry rooms. PVA-based paints are the cheapest of all water-based paints. The addition of acrylic polymers to PVA-based paints to some extent increases the water resistance and wear resistance of the finished coatings. However, these paints are still inferior to paints based on pure acrylic binders, although their cost is almost the same.
Styrene-butadiene dispersions have good water resistance, but have limited light fastness (yellow when exposed to light). This significantly limits their use. Paints based on this type of binder are inexpensive and, if necessary, are used only indoors, with dim artificial lighting.
Acrylic dispersions are more expensive, but they are the most versatile. Paints based on acrylic binders (acrylic paints) make up the most significant part of all water-based paints. It is they that are much more often used for interior decoration.
Acrylic paints are perfectly tinted with up to 15,000 different colors and shades. It should only be borne in mind that different manufacturers have their own tinting systems, and the color shades of different systems may not coincide.
Acrylic paints retain their color well and withstand intense ultraviolet radiation. In addition, they are easy to use and dry quickly. High-quality acrylic paints make it possible to create flexible coatings, capable of bridging "hair" cracks in the base up to 0.5 mm, they are durable and resistant to washing. New purely acrylic binders make it possible to produce paints adapted to the specifics of 'living' wood, that is, with high elasticity, water-repellent properties and, at the same time, high vapor permeability ('breathability').
A wide variety of binders for water-dispersion paints makes it possible to create on their basis paint and varnish compositions for various purposes, characterized by ease of use and quick drying, and the absence of volatile diluents makes it possible to classify these compositions as environmentally friendly materials.
When choosing the type of paints, it is necessary to know exactly the capabilities of a particular material and measure them with the requirements that face the coating. Only in this case, it is possible to save on material, because no material good or bad, expensive or cheap. There are materials that are optimal for these conditions. In conclusion, let us compare the main indicators of water-dispersion paints on various binders.
Water resistance. It is low for PVA-based paints, and high for styrene-butadiene and acrylic paints. Therefore, you should not use PVA-based paints in rooms with high humidity, for example, in bathrooms, in kitchens, in the basement. Perhaps the only place where this type of paint is preferable is ceilings in dry rooms. But you should not paint the ceiling with PVA-based paint in a summer house that is not heated in winter.
Lightfastness. For PVA-based paints and acrylic paints this indicator is high, for styrene-butadiene systems it is noticeably lower. Therefore, styrene-butadiene paints (latex) can compete with acrylic paints only in low-light rooms, for example, in hallways, basements.
Mechanical and weather resistance. This indicator is the highest in acrylic paints, especially if the surface is wetted. Those. if the coating needs to be washed periodically or it experiences frequent mechanical stress, for example, in the entrance, then acrylic paints should definitely be preferred.