A kind of polyurethane emulsion and its preparation and use

Abstract

The invention discloses a polyurethane emulsion and a preparation method thereof, which are prepared by reacting the following raw materials: a) dopamine, b) at least one diisocyanate, c) at least one polyether polyol, d) at least one side-containing Methyl polyester polyol e) at least one liquid rubber polyol, f) at least one hydrophilic compound component, and g) optional small molecule amine chain extender. The emulsion prepared by the present invention simultaneously introduces a polymer main chain structure with lower polarity and a dopamine group with good adhesion on the surface of a low-polarity substrate, and the synergistic effect of the two enables the obtained emulsion to be stable at room temperature. Scratch coating on untreated PP sheet, after drying and curing, it can achieve high-strength bonding between PP sheet and PVC leather, with lower VOC content, and well avoids pretreatment of PP substrate during construction. It can be used in the field of bonding of low-polarity substrates such as PP sheets for automotive interiors.

Description

technical field [0001] The invention belongs to the field of polymer materials, in particular to a polyurethane emulsion and a preparation method thereof, as well as its use as an adhesive in a PP base material. Background technique [0002] As one of the five general-purpose plastics, polypropylene (PP) is non-toxic and tasteless, has a wide range of sources, 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, its surface tension is low and its crystallinity is high, which makes it difficult to adhere compared with general plastic products. In order to improve the adhesion to the PP surface, surface treatment is generally carried out by flame treatment, plasma treatment, radiation method, microwave method and corona discharge method to increase its surface ener...

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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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