Preparation And Properties Of Waterborne Heat Insulating Coatings With Multiple Mechanisms

The mass use of refrigeration equipment to reduce the influence of solar radiation have caused severe energy consumption and aggravated greenhouse effect.So it is of great significance to develop energy-saving and low-cost waterborne heat insulated coatings.The work employed acrylic resin as the film forming substance to prepare two types of composite heat insulated coatings.It aimed to explore the potentiation of insulation and radiation relative to traditional heat reflective coatings.At the same time,the coatings were supposed to satisfy the requirement for outdoor applications.In chapter two of the thesis,mechanism of heat reflection and insulation were combined to in the preparation of coatings.One was a double-layer coating.Hollow glass microsphere?HGM?and rutile TiO₂ were used as the fillers in sublayer and upper layer,respectively.Optimum particle volume concentration?PVC?of HGM and TiO₂ were 60%and 30%.Based on good weather ability and stain resistance,maximum solar reflectance was 90.0%.Temperature difference characterized by self-made test apparatus was 27.4?.The other was a single-layer coating.Anatase TiO₂ modified HGM was prepared via sol-gel method and used as the filler.Solar reflectance and temperature difference were 81.8%and 19.7?.The work applied a combination of reflection and radiation mechanism to develop coatings in chapter three.Carbon nanotubes?CNTs?and nano SiO₂ were adopted as radiative fillers in the sublayer.With the thickness of 100?m,0.5%CNTs and 6%nano SiO₂ provided the radiative layer with the best hemispherical emissivity of 93%.Meanwhile,CNTs were beneficial to improve the pencil hardness of the coating from 2H to 3H.After adding a reflective upper layer filled with TiO₂,solar reflectance and temperature difference of the composite coating were 87.1%and 26.7?.There was a promotion of 9?compared to normal reflective coatings.The coatings behaved well in artificial accelerated aging test,acid and alkali-base immersion test and salt spray test.It proved that the coatings had the ability to withstand outdoor environment.