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What are the classifications of waterborne polyurethane floor paint coatings?

Update:Water-based polyurethane floor paint is formulated with water-based polyurethane resin as the base material and water as...
Summary:11-07-2022
Water-based polyurethane floor paint is formulated with water-based polyurethane resin as the base material and water as the dispersion medium. Generally, it can be divided into three categories: one-component, two-component and modified water-based polyurethane floor paint.
 
1. One-component water-based polyurethane floor paint
One-component water-based polyurethane is the earliest water-based polyurethane coating, which seals all the components of the coating in one package. As a coating, it generally does not require high relative molecular weight in order to form a good and stable dispersion, so one-component waterborne polyurethane coatings are usually low molecular weight or low cross-linking, and their chemical resistance and solvent resistance are not good. , its hardness, surface finish and vividness are not as good as solvent-based two-component polyurethane coatings. In order to further improve the mechanical properties and chemical resistance of waterborne polyurethane coatings, reactive groups are often introduced for crosslinking.
 
2. Water-based two-component polyurethane coating
Two-component waterborne polyurethane coating includes two components: one component contains active hydrogen, such as radicals, which are often made into waterborne dispersions of radical-functionalized polyurethane; the other component contains isocyanate, mostly aliphatic isotopes. Cyanate esters, aromatic isocyanates can also be used, generally referred to as curing agent components. The two components are packaged separately and then mixed well for application. It is mainly formed by the cross-linking reaction of hydroxyl and isocyanate to form a tough coating. Although some isocyanates will react with water when the two components are mixed, and the generated carbamate will be decomposed into amines and carbon dioxide, the amines and isocyanates can further react to form pulses and solidify, but the difference between isocyanates and water The reaction rate is much lower than the evaporation rate of water, so the effect of this reaction on the coating film can be ignored.

3. Modified waterborne polyurethane coating
Although polyurethane coatings have many advantages, they are not perfect. For example, polyurethane coatings have poor color retention, higher prices, and structurally attractive hydrophilic groups that make the coating less water-resistant, so try to improve The comprehensive properties of water-based polyurethane coatings are very important. Studies have shown that the blending, grafting or copolymerization of polyurethane and acrylic resin can effectively improve the performance of coatings, and the organic combination of the two is an important way to develop the third-generation new water-based polyurethane. At present, water-based polyurethane coatings have been developed from physical mixing modification to chemical modification. For example, core-shell emulsion polymerization of acrylic acid is carried out in polyurethane water dispersion to form an interpenetrating network and enhance the The bonding force between polyurethane and acrylic resin improves the resistance to the penetration of water, alkali and other solvent molecules, so that the water resistance, solvent resistance and alkali resistance of the coating are significantly improved.