Polyurethane emulsion as well as preparation and application thereof

Abstract

The invention discloses a polyurethane emulsion as well as a preparation method thereof. The polyurethane emulsion is prepared by the reaction of the following raw materials of: a) dopamine, b) at least one diisocyanate, c) at least one polyether polyol, d) at least one polyester polyol containing side methyl, e) at least one liquid rubber polyol, f) at least one hydrophilic compound component, and g) an optional micromolecular amine chain extender. According to the prepared emulsion, a polymer main chain structure with low polarity and a dopamine group with good adhesive force on the surface of a low-polarity base material are introduced at the same time, and through the synergistic effect of the polymer main chain structure and the dopamine group, the obtained emulsion can be applied on a PP plate which is not treated at room temperature; the high-strength bonding of the PP plate and PVC leather can be achieved after drying and the curing; the VOC content is low, the tedious process flow of the pretreatment of the PP base material during the construction process is well avoided; and the polyurethane emulsion can be used in the field of the bonding of low-polarity base materials such as automotive interior PP plates.

Description

technical field [0001] The invention belongs to the field of macromolecular materials, and in particular relates to a polyurethane emulsion and a preparation method thereof, and relates to its use as an adhesive in PP substrates. Background technique [0002] As one of the five general-purpose plastics, polypropylene (PP) is non-toxic, tasteless, wide source, low price, simple manufacturing process, excellent mechanical properties, heat resistance and chemical stability, and is widely used in industrial products, daily necessities, Automotive, packaging materials and other fields. However, since PP is a non-polar polymer with low surface tension and high crystallinity, compared with general plastic products, it is difficult to adhere. In order to improve the adhesion to the surface of PP, the surface is generally treated by flame treatment, plasma treatment, radiation, microwave and corona discharge to increase its surface energy. However, these treatment methods will be r...

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Problems solved by technology

[0005] In the previous research, we proposed a low-polarity isocyanate-terminated prepolymer in the 2019112835796 patent application, which can have excellent adhesive properties on PP sheets through moisture curing, although there is no Contains a solvent, but the viscosity of the prepolymer is relatively high, which will affect the construction efficiency during the painting process. How to convert this prepolymer into a low-viscosity emulsion while maintaining good adhesion will become the next key research topic

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