Synthesis of porous polyurea microspheres for matting coating

A type of porous polyurea microspheres for matting coating were prepared by precipitation polymerization in H2O/Acetonitrile (AN) solution, using isophorone diisocyanate (IPDI) as polymerized monomer, 2, 4-diaminobenzene-sulfonic acid sodium salt as hydrophilic monomer and polyvinylpyrrolidone (PVP) as porogen. The effect of the type of porogen, reaction temperature, dry methods, post-perforation method and polyvinylpyrrolidone loading on the surface porosity was investigated. Meanwhile, the effect of the surface porosity and roughness of microspheres on the matting properties of the coating was also investigated. The results indicated that PVP porogen has played an important role in regulating the surface porosity of microspheres and shows superior perforation. When 15 wt% PVP (based on isophorone diisocyanate loading) was used as porogen, the reaction was carried at 50 degrees C in a shorter time, and the crude product was dried in a state of water dispersion at 100 degrees C, the resultant microspheres with maximal porous surface can be achieved. Post-perforation can further increase the surface roughness and porosity of polyurea microspheres without changing its particle size. When 5 wt% porous polyurea microspheres were added to the water-based polyurethane (WPU) coating, the gloss of the coating decreased from 6.27 degrees to 1.14 degrees (60 degrees incident angle).

Automated summary

A type of porous polyurea microspheres for matting coating were prepared by precipitation polymerization, and the factors affecting the surface porosity and roughness were investigated. The results showed that polyvinylpyrrolidone played an important role in controlling the surface porosity, and adding porous polyurea microspheres significantly reduced the gloss of the coating.