| Humidity has an impact on both the working efficiency and health of occupants,the indoor humidity reveals a significant role with daily or seasonal variation. Thus, it isknown that the humidity controlling becomes particularly important. In recent years, thehumidity controlling materials have been researched for their moisture absorption anddesorption properties. The humidity controlling coating was one of the humiditycontrolling materials, and it was different from the conventional coatings. They musthave strong absorption and good water retention, which means faster response for water.They could be coated on surface to form a protective, decorative and humidity-sensitivecoating.The object of this paper is based on the preparation of acrylic copolymer andhumidity controlling coating of our research group. By waterborne polyurethanemodified acrylate to prepare waterborne polyurethane acrylate composite emulsion, andthen, inorganic porous multi-layer material as pigments and fillers, were applied thewall coatings with humidity controlling functions. This paper is divided following parts:Firstly，the method of acrylate modified waterborne polyurethane emulsion athome and abroad were reviewed in this paper, the main tasks are performed on twoaspects: on the one hand, the developing situation of waterborne polyurethane coating isexpounded. On the other hand, this paper illustrates the basic methods of acrylatemodified waterborne polyurethane. Finally, it introduces the application and prospect ofacrylate modified waterborne polyurethane.Secondly, based on parameters of exploration such as different ratio of NCO/OH,reaction temperature. Finally get the best process of waterborne polyurethane emulsionwas synthesized. And then waterborne polyurethane/polyacrylate emulsion wasprepared by physical blending waterborne polyurethane emulsion and polyacrylateemulsion. At the same time, the structure and chemical components of the waterbornepolyurethane-polyacrylate hybrid nanoparticles were investigated by transmissionelectron microscopy (TEM), FT-IR spectra and thermo gravimetric analysis (TGA),respectively. We found that there are hydrogen bonds in the compound emulsion andthe hydrogen bonds enhanced the compatibility of polyurethane and polyacrylate. Then,the humidity controlling coating was prepared by the emulsion which have functional film-forming properties and pigments and fillers, such as bentonite, diatomite and otherclay. And the basic performances of the coating were measured, the experimental resultsdemonstrated that they reached to Chinese standard about interior wall coating (GB/T9756-2009). Moreover, the obtained coating was characterized by SEM and thehumidity mechanism was suggested.Thirdly, waterborne polyurethane-acrylic copolymers crosslinked core-shellemulsion (PUA) was prepared. The different proportions and the contents of DMPA andHEMA on stability of core monomer and shell monomer were studied, respectivley.The best reaction temperature, the best dosage of KPS, Tween-20/SDS, MMA/BA rateand PA/PU rate on the stability of PUA emulsion were investigated. By FT-IR, TG,TEM, DLS proves that waterborne polyurethane/acrylic copolymer crosslinkedcore-shell structure and the formation mechanism of crosslinked core-shell structurewas suggested. Then, the humidity controlling coating was prepared by the emulsionwhich have functional film-forming properties and pigments and fillers, such asbentonite, diatomite and other clay. The obtained coating was characterized by SEMand the basic performances of coating were measured, the experimental resultsdemonstrated that they reached to Chinese standard about interior wall coating (GB/T9756-2009).Fourthly, waterborne polyurethane-acrylate composite emulsion was prepared byfine emulsion method, and we studied DMPA, HEMA, PA/PU, HD on the influence ofemulsion particle size and conversion rate. By FT-IR, TG, TEM proved thatwaterborne-acrylate composite emulsion was successfully prepared. Then, the humiditycontrolling coating was prepared by the emulsion which have functional film-formingproperties and pigments and fillers, such as bentonite, diatomite and other clay. And thebasic performances of coating were measured, the experimental results demonstratedthat they reached to Chinese standard about interior wall coating (GB/T9756-2009).Moreover, the obtained coating was characterized by SEM.In conclusion, waterborne polyurethane-acrylate humidity controlling coatings metthe standard for interior wall coatings and the scrub resistance was very high. They hadexcellent properties of humidity sensitivity and humidity retention, and they could bewidely used in indoor coatings for controlling humidity. |
PDF Full Text Request