Preparation method of solvent-free waterborne polyurethane resin

Abstract

The invention discloses a preparation method of a solvent-free waterborne polyurethane resin. The preparation method specifically comprises: (1), adding amino type cage type silsesquioxane into excessive isocyanate monomers at 20-80 DEG C, reacting until the solution is clear; (2), adding ethyoxyl sealed polymer glycol, hydrophilic functional monomer, dihydric alcohol and catalyst di-n-butyltin dilaurate into the solution obtained in the step (1) (wherein the R value is controlled to be 1.50-3.00 during a pre-polymerization reaction process), reacting for 1-2h at 40-70 DEG C, then heating to 70-90 DEG C, keeping reacting for 1-2h, and then cooling to normal temperature; (3), adding neutralizer and water into the solution obtained in the step (2), and diffusing; and (4), adding a chain extender at 30-50 DEG C, carrying out chain extending reaction for 2-4h, and cooling to normal temperature, so as to obtain the waterborne polyurethane. The solvent-free waterborne polyurethane resin prepared by the method disclosed by the invention has excellent viscosity, adhesive strength and wearing resistance.

Description

technical field [0001] The invention belongs to the field of polymer materials, and in particular relates to a preparation method of a solvent-free waterborne polyurethane resin. Background technique [0002] Waterborne polyurethane is an emerging polymer material developed from water as a dispersant instead of organic solvents. Its special molecular structure and aggregation state make it have excellent properties such as abrasion resistance, flexibility, adhesion and chemical resistance. The coating film formed by it has good mechanical properties, good wear resistance, high hardness, water resistance, chemical resistance, aging resistance and other excellent properties, and can be widely used in textiles, printing and dyeing, leather processing, coatings, adhesives, wood processing, fields such as construction and papermaking. [0003] The preparation method of waterborne polyurethane can be divided into two kinds: external emulsification method and self-emulsification m...

AI Technical Summary

Problems solved by technology

In the process of synthesizing the prepolymer, the viscosity of the system is high, which will cause uneven mixing of materials and difficulty in heat transfer, which is not conducive to obtaining a stable dispersion

For the viscosity problem of the prepolymer, the traditional solution is to add a large amount of organic solvent with low boiling point to help reduce the viscosity, and then remove the organic solvent by vacuuming after the product is obtained. The disadvantage of this method is that it consumes a large amount of organic solvent and energy. Some volatile organic solvents remain in the system, which will pollute the environment. At the same time, the prepared products have the disadvantages of low strength and general wear resistance, so it is difficult to meet the needs of the growing market

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