Synthesis And Properties Of The Polyurethane Polyol Dispersions Modified By Silicone/Fluorine

Polyurethane material plays a very important position in the coatings industry with its excellent physical and mechanical properties, water resistance, solvent resistance, etc. With the continuous improvement of environmental regulations, high-performance, low VOC waterborne coatings, especially two-component waterborne polyurethane coatings (2K-WPU) gradually become a hot topic in the coating industry. The two-component waterborne polyurethane is mainly composed of water polyol component and polyisocyanate component.The water polyol component includes polyester polyol, acrylic polyol and polyurethane polyol. In the preparation of 2K-WPU, select the right hydroxyl component directly determines the performance of the two-component cured coating film. Among them, the polyurethane polyol dispersions has good dispersion capacity, better compatibility with the curing agent,and the film properties can be adjust for a wide range by adjusting the content of urethane bonds.Now, the polyurethane polyol dispersions has caused widespread concern in the paint workers.In the first chapter, the two forms of waterborne polyurethane coatings, single-component and two-component were described.Then introduced the status of the application research progress of single-component and two-component waterborne polyurethane coatings.In the second chapter, a polyurethane polyol dispersions have been successfully synthesized with diethanolamine as the blocking agent for introducing hydroxy, which were prepared beforehand with toluene diisocyanate, polyether polyols, dimethylol propionic acid and trimethylol propane as the main raw materials, and then use the polyurethane polyol with the hydrophilic modified polyisocyanate curing agent prepared by mixing two-component waterborne polyurethane coatings. The synthesis processes of polyurethane polyol were characterized by FT-IR. The results show that the coating hardness, water resistance and other properties were the best when the DMPA mass fraction was 4%, TMP mass fraction was 5%, DEA mass fraction was 7%, the ratio of -NCO/-OH was 1.4, at this time, the resulting tensile strength of two-component waterborne polyurethane film was 13.4Mpa, breaking elongation was 98%.In the third chapter, a polyurethane polyol dispersions have been successfully synthesized with diethanolamine as the blocking agent for introducing hydroxy, which were prepared beforehand with toluene diisocyanate, polyether polyols, hydroxyl silicone and dimethylol propionic acid as the main raw materials. The polymer were characterized by IR and 1H-NMR, and studied the effects of hydroxyl silicone oil content of the emulsion polymer particle size, viscosity, stability and film water resistance, mechanical properties, thermal properties. The results show that: with the increase of the content of hydroxy silicone oil, the particle size of the emulsion and the water contact angle increases, the viscosity reduction, film tensile strength and water absorption decreased, increased elongation at break. When the hydroxyl silicone content is 5%, the film has the best comprehensive performance, at this time, the emulsion particle size is 92.4nm, water contact angle is 93°, the tensile strength is 5.5MPa, and elongation at break is 621%, water absorption of 48 hours is 7.6%.In the fourth chapter, a hydrophilic polyurethane prepolymer terminated with double bond was synthesized with HEMA as the blocking agent for introducing C=C which were prepared beforehand with toluene diisocyanate,polyether polyols,dimethylol propionic acid and 1,4-butanediol as the main raw materials. Respectively introduced the hydroxyl groups with diethanolamine (DEA) and hydroxyethyl methacrylate (HEMA), then introduced the organic fluorine by radical copolymerization, get an organic fluorine-modified polyurethane polyol waterborne dispersion. The polymer were characterized by IR, and studied the effects of fluorine content and hydroxyl introduced way on the dispersion properties. The results show that the heat resistance, water resistance and mechanical properties of the polyurethane polyol waterborne dispersion were increased with the addition of organic fluorine; When introducing the same amount of hydroxyl, DEA has a smaller particle size and higher mechanical stability of the resulting dispersion than HEMA; With increasing of n (TDI)/n (HEMA), the particle size of the dispersion was basically unchanged.