Method for preparing carboxylic acid/sulfonic acid mixed waterborne polyurethane with high solid content with solvent-free process

Abstract

The invention discloses a method for preparing carboxylic acid / sulfonic acid mixed waterborne polyurethane with high solid content with a solvent-free process. The method comprises the steps as follows: firstly, 10-30 parts of polymer diol, 0-2 parts of micromolecular polyhydric alcohol, 6-20 parts of diisocyanate and 0-0.5 parts of a catalyst are added to a reactor to react at 60-90 DEG C for 2-4 h; then, 0.3-3 parts of a carboxyl-containing hydrophilic chain extender are added, and the mixture reacts at 60-90 DEG C for 2-4 h; the product is cooled to 60 DEG C or below, 0.2-2.5 parts of a neutralizer are added, the mixture reacts for 5-45 min, and an ionomer is obtained; 20-70 parts of water are added to the ionomer under the violent stirring condition, and the ionomer is stirred for 1-5 min; finally, 0.3-3 parts of a hydrophilic chain extender containing amino and sulfonate groups are added to a waterborne polyurethane dispersion liquid to react for 5-60 min, and the carboxylic acid / sulfonic acid mixed waterborne polyurethane with high solid content not lower than 45% is obtained. No organic solvents are used during production, the method is economical and environmentally friendly, and prepared waterborne polyurethane has high solid content and has the advantages of being short drying time, low energy consumption, low transportation cost and the like.

Description

technical field [0001] The invention relates to the field of water-based polyurethane resins, in particular to a method for preparing carboxylic acid / sulfonic acid mixed high-solid-content water-based polyurethane by a solventless method. Background technique [0002] With the enhancement of people's awareness of environmental protection and the increasing attention to environmental pollution in various countries, water-based polyurethane is gradually replacing solvent-based polyurethane and is widely used in many fields such as coatings, adhesives, leather, and textiles. Water-based polyurethane uses water as the dispersion medium, no VOCs emissions, and the water is cheap and safe to use. However, at present, the solid content of water-based polyurethane is about 30%. Since the latent heat of evaporation of water is higher than that of organic solvents, there are disadvantages of long drying time and high energy consumption, which greatly restricts the popularization and a...

AI Technical Summary

Problems solved by technology

[0005] After obtaining the water-based polyurethane, the organic solvent is removed by vacuum distillation, which not only consumes a large amount of organic solvent and energy, but also increases the process flow; moreover, some volatile organic solvents remain in the system, which is difficult to obtain during subsequent use. It will still pollute the environment and is not a real environmental protection product

In addition, the acetone removal process requires high equipment and large investment

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