Waterborne polyurethane, preparation method therefor and waterborne transfer painting

Abstract

The invention provides a preparation method for waterborne polyurethane. The preparation method comprises the following steps: (A) isophorone diisocyanate and polyester dihydric alcohol are reacted to obtain prepolymers; (B) the prepolymers, alcohol chain extenders and hydrophilic chain extenders are mixed and subjected to chain extension; (C) the compounds obtained from the step (B), salt forming agents and water are mixed and reacted to obtain waterborne polyurethane. The waterborne polyurethane is prepared through an internal emulsification method and has good hydrophilicity because the waterborne polyurethane contains hydrophilic groups. The invention also provides a waterborne transfer painting. The waterborne transfer painting comprises waterborne polyurethane, deionized water, antifoaming agents, wetting dispersants, flatting agents and antiseptics. The waterborne transfer painting employs waterborne polyurethane as a waterborne transfer resin. Because hydrophilic groups are introduced into polyurethane macromolecule, The waterborne transfer painting is soluble in water. The waterborne transfer painting employs deionized water as a dispersion medium, so the waterborne transfer painting has high safety and environmental protection.

Description

technical field [0001] The invention relates to the technical field of coatings, in particular to water-based polyurethane, a preparation method thereof and water-based transfer coatings. Background technique [0002] The early gold and silver cardboard used in the packaging boxes of tobacco, wine, food, daily necessities, etc. was mainly produced by the composite method, that is, the aluminum foil or aluminized film is directly composited with the paper. Although the process is simple, the aluminum foil and plastic film in the product cannot be degraded and Recycling causes environmental pollution and a large waste of resources. In order to protect the environment and save resources, people have developed a direct plating process and a transfer process. [0003] The direct plating method is to directly vapor-deposit the paper with a vacuum aluminum plating machine, but there are many problems, for example: the moisture content of the paper changes greatly when the aluminum...

AI Technical Summary

Problems solved by technology

[0004] The transfer coatings currently used are all organic solvent-based, that is, oil-based coatings, which use various organic solvents such as: benzene, ketones, lipids, ethers, etc. as dispersion media. The above solvents are easy to volatilize and cause irritation and the volatile solvents cannot be recycled in large quantities, which not only causes waste but also pollutes the environment, and brings safety hazards to production. At the same time, the cost of organic solvents is relatively high

Therefore, if the water-based transfer coating is used, it will not only take into account the various performance characteristics that the transfer aluminum plating coating should have, but also solve the impact on the environment caused by the large amount of solvents discharged into the atmosphere during the production of solvent-based coatings.

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