General knowledge of coating: basic modification method of Waterborne Polyurethane

Core tip: waterborne polyurethane has some disadvantages, such as poor water resistance, low hardness and mechanical strength of the coating, which need to be modified The most important part of waterborne modified polyurethane coating is waterborne polyurethane modified acrylate resin The main progress of waterborne modified polyurethane material is the development of chemical modification (called "in situ polymerization") from the original physical mixing modification, which combines the toughness and elasticity of polyurethane resin with the good color retention, light stability, hardness and low cost of acrylic acid vinegar, In other words, acrylate is the first solvent for polyurethane synthesis, Application scope and advantages of roller ceramic coating Recommended introduction: the surface of ceramic rubber plate used for roller ceramic coating is cast into durable rubber plate by hundreds of independent small ceramic pieces Each ceramic piece has raised characteristics Under general conveyor belt pressure, thousands of unique cast bumps can produce positive traction, prevent slipping and extend the service life of conveyor belt roller At the same time, the bottom layer adopts high-quality rubber, which has strong elasticity and can play a good impact resistance role The scope of application of roller ceramic coating is one three six 83857180 (the same as V) 1 Roller coating in extremely harsh working environment 2 The belt joint is not suitable for fixing with iron buckle; 3 It is suitable for leather Home of coatings: waterborne polyurethane has some disadvantages, such as poor water resistance, low hardness, low mechanical strength, which need to be modified The most important part of waterborne modified polyurethane coating is waterborne polyurethane modified acrylate resin The main progress of waterborne modified polyurethane material is the development of chemical modification (called "in situ polymerization") from the original physical mixing modification, which combines the toughness and elasticity of polyurethane resin with the good color retention, light stability, hardness and low cost of acrylic acid vinegar, In other words, acrylate is used as the solvent for polyurethane synthesis, and then dispersed in water as the reaction monomer for polymerization In this way, the properties of the modified materials can be improved At present, copolymerization of polyurethane and polyacrylic acid is also a common modification method In addition, polyurethane modified epoxy resin, modified polyether and modified alkyd resin are also used in the types of modified materials Epoxy resin is a kind of thermosetting polymer synthetic material with good adhesion, corrosion, insulation and modified strength The main methods of waterborne polyurethane modification are as follows: (1) organosilicon modified organosilicon compounds contain element silicon in their molecular structure, which belongs to organic and semi-inorganic macromolecule compounds They have the characteristics of organic compounds and inorganic compounds The silicone modified polyurethane can make up for the defect of poor hydrolytic resistance of waterborne polyurethane, which makes the modified waterborne polyurethane paint show good hydrophobicity, surface enrichment, low temperature flexibility and good biocompatibility Silicone modified polyurethane can be carried out by physical blending For example, waterborne polyurethane and polysiloxane emulsion are used for physical blending modification Therefore, the most common method of silicone modified polyurethane is copolymerization Block copolymers were prepared by the gradual addition of polysiloxane oligomers with reactive functional groups at both ends (the most common is PDMS, or polysiloxane obtained after partial methyl was replaced) and polyisocyanates (2) The epoxy resin modified by epoxy resin is a polyhydroxy compound In the reaction with polyurethane, the branched point can be introduced into the main chain of polyurethane to form part of the network structure and have better performance Epoxy modified polyurethane emulsion was prepared by graft copolymerization of epoxy resin and polyurethane, and waterborne epoxy modified polyurethane coating was prepared with this method The chemical stability, corrosion resistance and adhesion of paint film could be improved (3) Compared with other synthetic polymer resins, acrylate modified acrylate has many outstanding advantages The hybrid aqueous dispersion of acrylic and polyurethane prepared by two kinds of polymers in micro state can obtain complementary properties Waterborne polyurethane / acrylate composite emulsion can combine polyurethane with higher tensile strength and impact strength, excellent abrasion resistance and good adhesion, weatherability and lower cost of acrylic resin (4) Nano materials modified by nano materials have special properties such as surface effect, small size effect, optical effect, quantum size effect and macro quantum size effect, which can make the materials obtain new functions (5) Vegetable oil modified vegetable oil is a kind of renewable resource The preparation of waterborne polyurethane coating with vegetable oil can further reflect the environmental protection consciousness The normal temperature crosslinked waterborne polyurethane resin coating synthesized with vegetable oil not only has good weather resistance, but also has the advantages of no pollution of waterborne coating It is an environment-friendly coating, which can be used as waterborne interior and exterior wall coating, It can also be used as wood decoration coating and textile printing and dyeing coating With air drying vegetable oil as the basic raw material, it was modified into a semi sealed PU molecular chain, and self emulsifying single component water PU was prepared The emulsion had good stability and excellent mechanical properties The intermediate of linolenic diethanolamine was synthesized by the amination reaction of linolenic oil and diethanolamine The water-based PU coating synthesized by this intermediate is water-resistant, fast drying, strong adhesion, non-toxic, non combustible, and easy to control viscosity It is an excellent environment-friendly water-based coating (6) Using mercaptoethanol as chain transfer agent, the hydroxyl terminated acrylate monomers were synthesized by free radical solution polymerization, Furthermore, the acrylate polymer with hydroxyl terminated fluorine was connected to the polyurethane chain segment to synthesize the waterborne polyurethane dispersion containing fluorine The test results showed that the surface fluorine of the membrane of the waterborne polyurethane dispersion containing fluorine formed and enriched Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire 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