Painting is a simple and affordable way to decorate a structure and protect it from dampness and ultraviolet radiation. However, the paintwork has a significant drawback: it is unstable to mechanical damage and short-lived. Polyurethane paint is free from these disadvantages.
Description and properties of paint and varnish material
Polyurethane compound - includes 3 main components, of which the binder has the most significant effect on properties.
Astringent - polyols... In the initial state, they are stabilized and inert. When mixed with a hardener, they become active. When the composition is applied to the surface and it comes into contact with air and moisture, polymerization begins. Polyols are converted to polyurethane and form a dense water-repellent film that is extremely resistant to mechanical damage.
Hardener - the medium with which the polyols are mixed. It can be either water or organic matter.
Modifier - additives that increase frost resistance, impart antiseptic and other properties to the mixture.
Polyurethane mixtures are used for indoor and outdoor use, for dry and damp rooms.
The characteristics of the composition are indicated on the packaging. You should study them before buying.
- Temperature range - from -40 to + 150 ° С.
- The admissible temperature range during application is -10– + 30 ° С. Air humidity does not matter.
- Adhesion - 2 points. The material adheres to concrete, brick, plastered wall, metal.
- The relative viscosity is 50–90 units.
- Elasticity at the fold - no more than 1 mm.
- Covering rate - 75 g / m², with normal dilution, the composition completely hides the texture of the surface.
The base composition is white. To give it a hue, a coloring pigment is added.
Scope of application
- private construction - for surface finishing;
- urban construction;
- automotive industry - for painting car bodies;
- agricultural facilities;
- chemical industry - the paint is resistant to chemically aggressive substances, therefore it is used for painting laboratories and workshops;
- production facilities - no other coating can last that long in a factory floor;
- road construction - road markings, allocation of zones, repair of bridges, flood structures.
The use of paint is limited only by its price.
Varieties of polyurethane paints
Polyurethane paint for walls and floors is made on the basis of polyols. However, a wide variety of substances can serve as hardeners and modifiers. In terms of composition, paints are divided into 4 categories.
- On organic solvents - refers to conditionally toxic, since the solvent is most often toluene or xylene.For good curing, this paint requires moisture in the air, therefore, the material is used for outdoor work and in damp, unventilated rooms. Dries quickly, reaches full strength in 2 days.
- Water-dispersive - water is used as a solvent. Completely safe, odorless, designed for use in living rooms, technical rooms. Somewhat less wear-resistant, but not afraid of water. Disadvantage: you can work with it only at temperatures above 0 ° C.
- Alkyd-urethane - universal, suitable for painting any surface, including wood and gas silicate. Extremely wear-resistant, insensitive to temperature changes. Dries up in 2 hours. It is applied in a thin layer, so the composition has to be applied in several layers.
- Alkyd-urethane two-component - forms the most durable wear-resistant coating. Does not burn, only melts, dries quickly in any conditions, withstands the highest loads, therefore it is usually used in industrial workshops and at car washes. Demanding to the surface.
Compositions are produced in 2 types - one-component and two-component. This does not indicate the number of ingredients in the mixture, but rather determines the method of use.
One-component mixtures - aqueous, on toluene - are a finished product. Shake the can before use, mix the contents of the can and immediately apply it to the surface.
Two-component offered in the form of two components: paint and hardener. Before use, the compositions are mixed in the right proportion and the paint is used within 6 hours.
Criterias of choice
Color mixtures are selected taking into account the following parameters.
- Appointment - there is no need to paint the walls in the kitchen with two-component polyurethane paint. Such a margin of safety is not required, and the cost of the composition is high. At the same time, the water-dispersion option is not suitable for finishing a car wash.
- Application method - Paints for roller or brush application and aerosol are available. The consumption of the composition from the spray is lower. However, a special device is required to work with it.
- Safety - you can not take compositions on organic solvents for finishing the bathroom, they are toxic when dried.
- Additional requirements - for example, for premises with a high degree of fire hazard, two-component mixtures are required, since they do not support combustion.
Consider the decorative effect. Polyurethane matte paint is more suitable for floors, glossy is more often used for wall and ceiling decoration.
Recommendations for use
The main rule when working with polyurethane paint is following instructions... There are other general guidelines as well.
- It is forbidden to dry the surface treated with the composition on an organic solvent with a stream of hot air. This will cause an intense release of toxins.
- For one-component paints, the surface need not be primed. Under two-component it is a must.
- When painting wood or other porous material, apply at least 2 finishing layers.
For priming concrete and plastered surfaces, it is recommended to take antiseptic compounds.
- "Teohim" - offers formulations for concrete and metal surfaces. It even produces food-grade paint, which is harmless in contact with water and food.
- LLC "TD KRASBYT" - offers one- and two-component alkyd-urethane mixtures.
- CJSC "ALP ENAMEL" - offers one- and two-component paints. Feature - high adhesion even to corrosive metal.
- Sikkens Redox - manufactures compounds that are especially resistant to sea water and the atmosphere of the sea coast.