* : * : admin * : 2019-07-23 * : 2
Polyurethane paint is polyurethane paint. It has strong and tough film, full gloss, strong adhesion, water resistance, wear resistance and corrosion resistance. It is widely used in advanced wooden furniture and metal surface. Its shortcomings are mainly foaming in the tide, film powdering and so on. Like polyester paint, it also has the problem of yellowing. Polyurethane varnish is called polyurethane varnish. The varnish film is bright and full, hard and wear resistant, oil resistant, acid resistant, chemical resistant and industrial waste gas resistant. It has good electrical properties and can be mixed with various tree esters. The formulation can be adjusted in a wide range to meet different needs. It is widely used in wood, automobile, aircraft, machinery, electrical appliances, instrumentation, plastics, leather, paper, fabrics, petrochemical and other aspects. Ester varnish.
1. Polyester paint is characterized by the formation of non-ring and/or ring-shaped hydrogen bonds between polymer molecules. Under the action of external forces, hydrogen bonds can be separated and absorb external energy (20-25 kJ per mole). When the external force is removed, the hydrogen bond can be formed again. Such hydrogen bond splitting, and then the formation of reversible repetition, so that the polyurethane film has a high mechanical abrasion resistance and toughness. Compared with other paints, polyurethane film has the highest elongation at break due to hydrogen bonding under the same hardness conditions, so it is widely used as floor paint, overtime paint, high decorative anticorrosive paint and so on.
2. Some kinds of coatings (e.g. epoxy, chlorinated rubber, etc.) have good protective function and worse decorative function, while others (e.g. nitrolacquer) have better decorative function and worse protective function. However, polyurethane paint is both protective and decorative, and can be used in the painting of advanced wood, piano, large passenger aircraft, etc.
3. The film has strong adhesion. Like epoxy, polyurethane can be configured into excellent adhesives. Therefore, the film has excellent adhesion to various surfaces (metal, wood, rubber, concrete, some plastics, etc.). The author's experience is that for some metal surfaces, the adhesion of polyurethane paint is slightly lower than that of epoxy paint, but for rubber, polyurethane paint is better than that of epoxy paint.
4. The elasticity of the coating can be adjusted according to the need. It can be adjusted from a very hard coating to a very flexible elastic coating. However, general paints such as epoxy, unsaturated polyester, amino alkyd, etc. can only be made into rigid coatings, which are difficult to give high elasticity.
5. Coating film has excellent chemical resistance, acid resistance, alkali resistance, salt solution, petroleum products, so it can be used as maintenance coating for drilling platforms, ships, chemical plants, oil tank inner wall coating, etc.
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