Synthesis And Preparation Of High Solid Content Waterborne Polyurethane Wood Coatings Containing Carboxylic And Sulfonic Groups

Many countries have promulgated much stricter supporting regulations to improve the deteriorating ecological environment. The development trend of the coatings industry is to formulate the environmentally friendly coatings. The waterborne coating for wood is especially for the further study due to its closer relationship with the living environment. The development of the waterborne polyurethane is slower than that of the solvent polyurethane since waterborne polyurethane shows some disadvantages such as low solid content and poor water resistance and et al.This paper based on complex carboxylate and hydrophilic sulfonate group, increase the solids content of the dispersion, combined with the compound chain approach of containing hydrophilic sulfonic groups chain extender agent and polyamine,Targeted synthesis high solids dispersion of waterborne polyurethane which can be used to prepare wood coatings, solved the problem what low solids content of commercially available waterborne polyurethane wood coatings, to solve the shortage of commercially available waterborne polyurethane wood coatings of low solid content. Contents of this paper are mainly the following four aspects:Select the appropriate monomers, and synthesis of hydroxyl terminated polyester polyo containing sulfonate group. Through experimental conditions, the synthesis technology of polyester was determined; The influence of the molecular weight of polyester resin on the dispersion and coating film properties was analyzed; And the polyester resin was characterized.Preparation polyurethane prepolymer of research requirements. The effects of N_NCO/N_OH and DMPA content on the dispersion and coating properties of the polymer were studied and analyzed.The preparation of waterborne polyurethane dispersion: By introducing sulfonate small molecule chain extender to increase the solids content of the dispersion, At the same time using the composite polyamine chain extender to increase the degree of branching of resin, and enhance resistance to dielectric properties of the coating; The effect of the amount of hydrophilic groups on the dispersion and coating properties, effect of the types of organic silicon modifying agent on the dispersion state, and effect of silicone modifier dosage on coating properties was studied; The Particle size and distribution of sulfonate/carboxylate complex waterborne polyurethane dispersion by characterized by means of scanning transmission electron microscope and dynamic laser scattering instrument.Preparation and coating performance testing of high solid content acid / carboxylate complex waterborne polyurethane wood coatings, and the effect of coalescent and matting agent additives on the hardness of coating film was studied. The wood coating solids content of 50% or more of study, Coating performance to fully meet requirement of the "GB / T 23999-2009 Water based coatings for woodenware for indoor decorating and refurbishing".