摘要

With the strengthening of environmental awareness and regulations, waterborne polyurethane (WPU), an environmentally friendly water-based resin, has been widely applied and studied. Currently, one of the main issues with WPU products in the adhesive field is the low solid content. Excessive water content in the product leads to problems in drying, production efficiency, and adhesive performance. Herein, the preparation methods for high solid content and low viscosity WPU, including optimizing the reverse transformation process, increasing the space utilization rate, reducing the hydration layer, internal and external emulsification, hyperbranched structure and composite modification, in recent years were reviewed. The effect of different factors on the phase inversion process was summarized, and the reverse rotation process optimization strategy by changing the technology and equipment was expounded. Solutions were presented for addressing factors that restrict solid content, such as limitations in emulsion particle packing density, hydration layer thickness, and viscosity. By increasing the solid content, the slow drying and insufficient bonding capacity issues in waterborne polyurethane adhesives could be resolved, which had practical significance for optimizing the preparation and application of WPU adhesives. ? 2024 Fine Chemicals.

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