Also known as water-emulsion, water-soluble or latex - water-dispersion paints are one of the most common, cost-effective and easy to use paints. In the interior they are mainly used for painting walls and ceilings. Some of them are also widely used externally. Water-dispersion compositions do not contain organic solvents, therefore they are environmentally friendly and do not pose a threat to the health of people working with them. Apply with a brush, roller or gun. The coatings they form have high adhesion to all substrates and have high performance characteristics. Depending on the type of polymeric binder, water-dispersion paints are divided into polyvinyl acetate, acrylic and butadiene styrene (rubber, also called latex). Paints based on polyvinyl acetate (PVA) dispersions have poor water resistance and a relatively narrow field of application. They are mainly used for interior painting of ceilings and walls in dry rooms. The products from this group are one of the cheapest water-dispersion paints. The addition of acrylic polymers to PVA paints to some extent increases the water and wear resistance of the coating. However, such paints are inferior to the mentioned indicators of paints with pure acrylic dispersions, although the prices are in many cases equalized.
Butadiene styrene dispersions have good water resistance, but under the action of light they tend to turn yellow. This significantly limits their use. They are used only for interior painting of rooms with dim, artificial lighting. Paints with this type of binder are relatively inexpensive.
Paints based on acrylic binders (acrylic paints) are the largest group of water-dispersion paints. They are more expensive, but also more universal - they are suitable for both indoor and outdoor use. It is no coincidence that they represent more than 70% of the paints produced in Europe. Acrylic dispersions are easily tinted to obtain more than 15,000 colors and shades. They withstand intense ultraviolet radiation without changing color. They are easy to use, dry quickly, durable and resistant to washing.
Latex (dispersed phase of synthetic rubber) is often added to water-based paints, which gives the paint-and-paint film a highly water-repellent effect. This creates water-based paints, which after drying are waterproof and can withstand more than 5000-10000 cycles of brushing. At the same time, latex-free water-based paints can only be lightly wiped off, and in rare cases. It should be emphasized that the water-repellent effect does not impede vapor permeability.
Another group of water-based paints are silicate. Due to their high air and vapor permeability, they are very often preferred for finishing facades of old buildings, whose walls are poorly protected from rising groundwater levels. These paints are also suitable for painting walls exposed to high humidity coming from inside the building. If the humidity in the walls is higher than the atmospheric, you should choose this type of paint. Conversely, if the atmospheric humidity is higher, the right choice will be among other types of paints. An important advantage of silicate paints is that they do not support the development of microorganisms and therefore do not need bactericidal additives.
In silicone paints, the binders are emulsified silicone resins. They belong to the latest generations of paints, combining the positive qualities of acrylic and silicate paints. First of all, this is due to the vapor permeability, which is as high in silicone paints as in silicate paints. At the same time, unlike silicate, they form a waterproof surface on which rainwater remains in droplets without being able to pass inside the wall. The film formed by the silicone paints does not exert surface pressure on the substrate, which is a particularly important advantage when painting the facade on plaster. Unlike acrylic polymers, silicone resins are not thermoplastic, i. do not soften when the temperature rises. This, combined with their strong water-repellent properties, means that facades finished with silicone paints are virtually free of dirt.
Silicone paints are highly permeable not only to steam but also to CO2. Therefore, they do not protect the reinforced concrete from corrosion, unlike acrylic paints, which have this property. Practically silicone paints are suitable for all types of mineral surfaces and are compatible with both mineral and acrylic latex paints. With these paints can be repainted and old silicone coating.
Mineral paints - cement and lime are used less frequently than the types of paints already considered. Cement paints form coatings with high vapor permeability and water resistance. Their use is most appropriate for painting concrete and brick surfaces exposed to such a strong impact of moisture that other paints would not withstand. The main area of application of lime paints is in old buildings with lime or lime-cement plasters. Here we must note that the color range of lime paints is limited and includes shades only from the light palette. In addition, lime paints are unstable to the effects of sulfur gases and aerosols, which are among the main air pollutants in urban and industrial conditions.
Compared to water-based paints, those based on organic solvents have two undeniable advantages. They can be used at negative temperatures - according to some manufacturers up to -20oC and even the recently applied, still unstabilized coating will not be damaged by rain. These features allow to significantly expand the boundaries of the active annual period for repairs, including autumn and spring. The use of such paints is theoretically possible in winter, but is associated with some technological complications in the application - it is necessary to pre-thaw and dry the substrate.
Specially developed thermoplastic acrylic resins, which are part of film formers, give a big impetus to the expansion of the market of organosoluble paints. Paints on such a basis not only have the above-mentioned advantages of organosilicon paints, but also have the ability to form as high quality coatings as the latest generations of water-based paints.
To limit condensation in the premises, special anti-condensation paints are applied. They are used for walls and ceilings of bathrooms, kitchens, wet rooms, swimming pools and more. This type of product solves the problems that arise when using traditional paints in conditions of high humidity - moisture retention in the walls, reducing adhesion between the coating and the wall, swelling and peeling of the paint. In addition, surfaces in wet areas often contain alkaline substances and salts, which crystallize after drying and are a prerequisite for poor painting if the paint is not chosen as appropriate. To avoid undesirable consequences of this kind, anti-condensation paints have a texture that is maximally permeable to water vapor, ie they can "breathe".
Humidity and heat in the premises are a prerequisite for the development of bacteria, fungi and lichens on the walls and ceilings. To solve this problem, paint compositions have been developed with correctly selected pigments, binders and suitable ingredients - biocides (bactericides, fungicides, algaecides), which act poisonously on the respective groups of organisms.