Preparation process for waterborne polyurethane emulsion

Abstract

The invention provides a preparation process for a waterborne polyurethane emulsion. The preparation process comprises the following steps: a) subjecting carbon dioxide copolymer polyol, aliphatic diisocyanate and a hydrophilic chain extender to a reaction under the action of a catalyst so as to obtain a reaction product; b) reacting the reaction product obtained in the step a) with an epoxy silane coupling agent and a salt forming agent so as to obtain a performed polymer; and c) adding water into the performed polymer, carrying out emulsification and then reacting the emulsified performed polymer with an amine chain extender so as to obtain the waterborne polyurethane emulsion. The waterborne polyurethane emulsion prepared by using the preparation process has good resistance to water soaking and yellowing.

Description

technical field [0001] The invention belongs to the technical field of organic polymer materials, in particular to a preparation process of water-based polyurethane emulsion. Background technique [0002] Polyurethane is a common polymer material, which refers to a general term for a class of polymers containing urethane bonds (-NHCOO-) in the main chain of the molecule, and can be widely used in coatings, adhesives, leather finishing agents, Paints, ink adhesives, paper sizing, packaging films, waterproof textiles and many other fields. Water-based polyurethane in polyurethane overcomes the shortcomings of solvent-based polyurethane due to the use of water instead of organic solvents as the dispersion medium. Due to its non-toxic, energy-saving, high-strength, safe and reliable characteristics, water-based polyurethane is gradually replacing traditional solvent-based polyurethane emulsions Material. [0003] At present, the synthesis method of water-based polyurethane emu...

AI Technical Summary

Problems solved by technology

However, the water-based polyurethane emulsion products synthesized by the internal emulsification method are easy to absorb water, which leads to poor wet adhesion of the product, is not resistant to water immersion, and is also prone to yellowing, resulting in great limitations in its practical application.

For example, the patent publication number CN104293159A discloses a synthesis process of water-based polyurethane coatings, which reacts polyether polyols and aromatic isocyanates and uses glucose as a cross-linking agent to synthesize water-based polyurethane emulsions, and then adds aminosilane coupling agent to the water-based polyurethane emulsions. However, the resulting modified water-based polyurethane emulsion has extremely low water resistance and is prone to yellowing

The patent with the publication number CN104449534A discloses a primer-free polyurethane glass glue, which uses polyether polyol and isocyanate as the main raw materials to synthesize a polyurethane prepolymer, and then adds glycidyl etheroxypropyl trimethoxysilane to the prepolymer Reaction obtains polyurethane product, yet, the water immersion resistance of gained polyurethane product is still relatively poor