Silicone modified waterborne polyurethane is also the 2 methods of blending modification and copolymerization modification. Can be achieved by blending waterborne polyurethane emulsion and polysiloxane emulsion blend.
Polyurethane polysiloxane emulsion can improve the resistance to oil, and silicone emulsion can improve waterborne polyurethane water resistance and solvent resistance, a blend of the two can obtain the effect of complement. But because of the presence of emulsifier, the properties of the modified blend on the final film have a negative impact, blending modification is only simple mechanical mixing, no chemical bond formation, silicone oil is easy to migrate, resulting in Xigan in short time. Copolymerization is silicone modified waterborne polyurethane polysiloxane oligomer by the most commonly used, both ends with reactive functional groups (e.g., hydroxyl silicone oil, amino silicone oil, amino or alkoxy terminated silane coupling agent) and isocyanate by addition polymerization, and prepared copolymers.
There are 2 different methods for synthesis of waterborne polyurethane modified by organosilicon. The synthesis method is the introduction of hydroxyl silicone oil or amino silicone oil into the polyurethane chain in the synthesis of prepolymer. The reaction activity of hydroxyl silicone oil is moderate, and the reaction process is stable. The extended chain method is the introduction of amino silicone oil in the process of prepolymer emulsification.