Advantages of polyurethane compositions as coatings
Polyurethanes are a group of chemical compounds-polymers obtained as a result of the chemical reaction of polyol resins with isocyanate hardeners. Isocyanate compounds are very reactive and their reaction with polyols proceeds spontaneously at normal temperature. Polyurethanes are universal products that, thanks to their durability, flexibility and resistance to chemical agents and abrasion, find very wide application. They are commonly used in the production of plastics, elastomers, insulation, hard and elastic foam, varnishes and various coatings. They are widely used in medical technology. They are the basis of many of the modern industrial adhesives, they are an indispensable part of the varnish-painting system in automotive and shipbuilding, in the maintenance and preservation of old vehicles and vessels. Polyurethane coatings are indispensable for preserving the qualities of outdoor wood surfaces.
Basically, the polyurethane coating is a liquid plastic that hardens and forms a hard and elastic layer on a given substrate (metal, concrete, wood, plastic). The fully hardened layer gives a lasting gloss to the surface, it is resistant to chemical agents, water, abrasion and temperature. The glossy finish repels water, resists corrosion and protects against scratches, stains and UV rays. One of the decisive arguments for the use of polyurethane products is their resistance to abrasion. For decades, polyurethanes have been used in highly abrasive environments due to their remarkable abrasion resistance compared to other elastomers, plastics and metals. Polyurethane parts and components of various systems consistently demonstrate up to 10 times better abrasion resistance than other elastomers.
The hardness of polyurethane products fills the gap between rubber vulcanizates and plastics. They are harder than rubber vulcanizates, which contributes to their remarkable load-carrying capacity, but are softer and more malleable than plastics, which accounts for their exceptional impact resistance and overall toughness. They are extremely tough, demonstrating very high shear and tear resistance. In many cases, polyurethane elastomers outlast metal, plastic or rubber in highly abrasive environments.
In terms of oil and chemical resistance, depending on the specific application, polyurethane products are available with oil and chemical resistance exceeding other materials.
Paints based on polyurethane resins are much more durable than "regular" paints, especially when applied to places where there is a lot of knocking and scratching.
"Normal" paints are available in a richer color range, but this is not an obstacle if a system with a base "normal" paint and a finish coat of colorless polyurethane varnish is applied.
The drying time of polyurethane paints, varnishes and coatings is a very important parameter. It can be modeled within wide limits depending on the needs and requirements of the respective applications. Usually this time is about 6 - 8 hours. Hardening takes 24 hours, and reaching optimal physical and functional indicators - 7 days.