Waterborne polyurethane (WPU) is a water-based dispersion material, and its unique low viscosity characteristics often bring construction challenges such as flow hanging and penetration. In order to solve these problems and improve its construction performance, self-leveling performance and storage stability, the addition of thickener has become a key step. The thickener not only endows the water-based polyurethane system with ideal thixotropy and suitable viscosity, but also meets the stability and performance requirements of its production, storage and use in many dimensions.

In waterborne polyurethanes, thickeners play multiple roles: first, their associated thickening function can effectively enhance the stability of the system; Secondly, it can precisely control the rheological properties to ensure the smooth construction process; Finally, thickeners also help reduce the settling of pigments or fillers and maintain the uniformity of the paint.

Due to the complex structure of water-based polyurethane association thickener, its thickening effect and viscosity performance are also significantly different. According to its characteristics, it can be roughly divided into two categories: pseudoplastic type and Newtonian type. Pseudoplastic thickener adsorbs on the surface of emulsion particles with strong hydrophobic base, which significantly improves the low shear and medium shear viscosity, and its main function is to thicken. The Newtonian thickener, while effectively increasing the viscosity, the improvement of low shear and medium shear viscosity is not obvious, therefore, through structural fine-tuning, this kind of thickener can also be used as a leveling agent.

In practical applications, the association thickener selected by waterborne polyurethane mainly includes two categories:

1. Thickener suitable for medium and low shear rate: This kind of thickener gives the surface of waterborne polyurethane a weak pseudoplastic rheological property, making it more stable during construction.

2. Thickener suitable for high shear rate: its rheological curve is closer to Newtonian type, which mainly plays a role at high shear rate (about 10000/s).

In order to obtain the best construction results and rheological properties, thickeners suitable for high shear rates and medium to low shear are usually used together. This can not only effectively reduce the flow phenomenon, but also minimize the amount of thickener, to achieve effective control of construction costs.