Water-based PU belongs to a non-polluting and environmentally friendly leather raw material. In the process of use, some methods of use need to be paid attention to. The following water-based pu leather manufacturer Huai’an Kaiyue Technology Development Co., Ltd. will introduce the problems in the process of using water-based PU.
The use of certain toxic solvents in the synthesis of polymer materials, but to ensure its recycling and reduce its residual rate in the product, is also the research content of polymer green synthesis. The synthesis of waterborne polyurethane resins is a typical example of this. Waterborne polyurethane resin is a uniform emulsion formed by dispersing polyurethane in water. It has the advantages of non-combustible, low odor, no pollution to the environment, convenient operation and processing, and is widely used as a binder and coating. Compared with solvent-based polyurethane adhesives, waterborne polyurethanes have the following characteristics:
(1) Most aqueous polyurethane resins do not contain reactive NCO groups, and thus the resin is mainly cured by the cohesive force and adhesion of the polar groups in the molecule. The carboxyl group, the hydroxyl group and the like in the aqueous polyurethane can participate in the reaction under suitable conditions to cause crosslinking of the binder.
(2) Viscosity is an important parameter for the performance of the adhesive. The viscosity of the aqueous polyurethane resin is generally adjusted by a water-soluble thickener and water.
(3) Since the volatility of water is worse than that of organic solvents, the waterborne polyurethane adhesive dries slowly and the water resistance of the material is poor.
(4) The aqueous polyurethane resin can be mixed with various aqueous resins to improve performance or reduce cost. At this time, attention should be paid to the electrical properties and acidity and alkalinity of the aqueous resin, otherwise the aqueous polyurethane resin may be agglomerated.
(5) The water-based polyurethane resin has small odor, easy operation, and easy to clean the residual glue.
