Synthesis Of Internal-crosslinking Cationic Waterborne Polyurethane

Currently, there are more and more anionic waterborne polyurethane products on the market, while the synthesis and application of cationic waterborne polyurethane is still not mature enough. One kind of internal-crosslinking cationic waterborne polyurethane resin was synthesized with the polyester diol(PE-1000) and trimethylolpropane polyglycol ether(YmerTMN120),which appearance and overall performance is very excellent. In a word, there are good prospects for development in areas used for water-based wood sealer.Firstly, this paper has identified the route of cationic waterborne polyurethane synthetic, successfully obtained the cationic waterborne polyurethane resin.In order to obtain good performance of cationic aqueous polyurethane resin, the subject of the first process conditions were investigated, respectively, including the synthesis reaction temperature, the end of the control requirements and the type and amount of catalyst choice of solvent volume is analyzed in detail. At the same time, we also studied the influence factors of resins. It includes resin’s appearance, particle size, viscosity, storage stability, water absorption rate, solid content, hardness, tensile strength and elongation at break, etc. Through the study we found that the average molecular,the properties of polyester diols species, N-methyl diethanolamine(MDEA) content, 1,6-hexanediol(HDO) content, castor oil(C.O.) type, the degree of neutralization and the chain coefficient affecting the resin’s properties. Studies had shown that when using PE-1000 and YmerTMN120 mixed, in a ratio from 1/5 to 1/4, the resin would have good properties.When the molecular weight of the resin was designed from 3000 to 5000, the total amount of hydrophilic monomer from 10.0% to 12.0%, the content of small molecular diol from 6.0% to 7.0%, the content of polyhydric alcohol from 5.0% to 6.0% of the preparation cationic waterborne polyurethane resin which would have high solids, high hardness, low viscosity, water resistance, alcohol and excellent performance.This paper has also prepared CWPU waterborne wood sealer when added wetting agents, film-forming additives, defoamers, thickeners to the prepared CWPU resins. At the same time,we found that the paint would have good performance when used dosage of wetting agent BL-240 0.7%, the amount of BYK028 0.5%, the amount of ethylene glycol butyl ether coalescent 0.8%, the amount of RM2020 1.2% and the dosage of leveling agent Tego® Glide 482 0.2%..When contrasted to the available in the market waterborne wood sealer, the CWPU water-based wood sealer of this paper shows much better performance than the un-sealed.