Method for preparing hydrophobic PU (polyurethane) film by ultraviolet radiation

Abstract

The invention relates to a method for preparing a hydrophobic PU (polyurethane) film by ultraviolet radiation. The method comprises the following steps of (1) mixing diisocyanate and polytetrahydrofuran to react; adding a crosslinking agent and a chain expander, and then adding dimethylolpropionic acid and a catalyst to react, so as to obtain the PU; forming a film, and performing heat treatment, so as to obtain the PU film; (2) enabling 4,4'-dihydroxy benzophenone and 1-bromododecane to react, so as to obtain 4,4'-bis-dodecaoxy diphenyl ketone oxime; enabling the 4,4'-bis-dodecaoxy diphenyl ketone oxime and hydrazine hydrate to react, so as to obtain 4,4'-bis-dodecaoxy diphenyl ketone oxime hydrazone; oxidizing the 4,4'-bis-dodecaoxy diphenyl ketone oxime hydrazone, so as to obtain long-chain alkyl diazomethane; (3) dissolving the long-chain alkyl diazomethane into a solvent, uniformly coating to the surface of the PU film, and radiating by ultraviolet rays, so as to obtain the hydrophobic PU film. The method has the advantages that the reaction process is simplified, and the problem of difficulty in synthesizing of the hydrophobic PU film is solved.

Description

technical field [0001] The invention relates to a method for preparing a hydrophobic polyurethane film by ultraviolet light irradiation, and belongs to the technical field of polyurethane materials. Background technique [0002] Polyurethane is an important class of polymer materials, and its chemical synthesis is mainly carried out through the polyaddition reaction of diisocyanate and diol. The structural design and synthesis of polymers are not only the basis of polymer chemistry, but also gradually extended to materials science, molecular catalysis, biomedicine and other fields. Therefore, exploring polyurethane synthesis methods and developing new polyurethane materials has important theoretical significance and potential application value. [0003] With the increasing emphasis on coating safety and environmental protection indicators, waterborne polyurethane is gradually accepted by the market due to its low hazard and low pollution characteristics. The dispersion med...

AI Technical Summary

Problems solved by technology

However, this hydrophobic modification method requires special functional groups on the surface of the polymer, and in order to ensure the smooth implementation of subsequent modification reactions, the functional groups (such as alkynyl, alkenyl, azide, etc.) The chemical properties are often relatively active and prone to side reactions and deterioration, which makes the synthesis of this type of polymer difficult, and is not suitable for the surface modification of commonly used polyurethane materials.

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