Polyurethane varnish - a modern finishing material

The development of modern technologies for the production of finishing materials makes it possible to produce all new and new products that have a number of unique properties. Such novelties include polyurethane varnish.

This material is a different composition of solutions of hydroxyl-containing polyfunctional isocyanates. Polyurethane varnish when applied to it forms a strong polymer on the surface with a three-dimensional structure. This process is due to the reaction of isocyanates with hydroxyl-containing components (incomplete polyesters obtained by the reaction of an excess of polyhydric alcohol with dibasic acid or with mixtures of monobasic and dibasic fatty acids).

Often used and partially saponified polyvinyl acetates, incomplete polyacetals, cellulose ethers, phenol formaldehyde and xylene-formaldehyde resins. Among the isocyanates used most often used toluene diisocyanate and its various mixtures. Hexamethylene diisocyanate and reaction products of excess toluene diisocyanate with polyhydric alcohol and hydroxyl-containing polyesters are also used. Working with these substances requires special precautions. That is why it is more practical to use "blocked" or "hidden" isocyanates, which are compounds that decompose readily when they are heated. This group includes reaction products of isocyanates with malonate, acetoacetic ether, ethyleneimine and phenylurethane. Polyurethane varnishes are dissolved with esters, ketones, chlorinated hydrocarbons, nitroparaffins. The diluent of these agents is xylene, toluene, an aliphatic hydrocarbon.

Polyurethane varnishes are available in the form of one-component or two-component compositions. In the second case, a separately prepared solution of hydroxyl-containing compounds or mixtures of these compounds and isocyanate solutions is mixed before use of this agent. Such a prepared two-component lacquer is stored for 4 to 48 hours. These varnishes are used for hot and cold curing. One-component hot curing lacquers made on the basis of so-called "blocked" isocyanates are considered to be unlimitedly stable.

Polyurethane varnish forms glossy, elastic coatings with high hardness, good adhesion, high dielectric properties and chemical resistance. They are increasingly used to protect concrete, metal, wooden surfaces and are used for painting equipment at chemical, metallurgical and oil refineries, at food enterprises.

Polyurethane varnish for parquet, furniture, rubber, paper, leather, ship structures, synthetic fabrics and plastics is produced. This coating is very durable and practical, it significantly increases the shelf life of various materials. One-component varnishes are often used to protect copper, aluminum and metal products.

Lacquer polyurethane water protects wooden walls and ceilings from fungi and mold. It is sufficiently light and heat resistant. This transparent coating allows you to perfectly emphasize the natural beauty of wood.