Formulation Design And Performance Studies On Silicate Heat-insulating Coating

Heat-insulating coating, can be used to prevent transmission of heat and reduce the temperature of coating surface effectively, reaches the destination of improving working environment and reducing energy consumption. Because of its economical efficiency, convince and reliable effect of thermal insulating, it has become a kind of important construction energy-saving material gradually. A kind of Silicate heat-insulating coating was studied in this paper, which was environment friendly and its process technology was simple. The coatings can be brushed at surface of metal and wall at room temperature and have reliable effect of heat-insulating.Firstly, modified research of the sodium silicate binder should be done, because the resistence to water and mechanical property of coating is not well at room temperature. Inorganic-modified and organic-modified to sodium silicate binder were employed. Modified reagent included inorganic acid, silica sol binder, polymer emulsion, et al. In the end, better mixture ratio was obtained as follows: sodium silicate: styrene-acrylic emulsion: inorganic acid: sodium methyl silicate: stabilizing agent = 100:20:5:5:1.Nextly, heat-insulating effect of several common heat-insulating filling were studied, establishing heat-insulating filling unit including hollow glass bead and sepiolite fiber, then modified research of hollow glass bead and sepiolite fiber were studied in experiment. For cenosphere, tio2 solution was made by liquid-phase process, surface of cenosphere was coated by immersion plating and gained modification cenosphere with high refractive index, it was detected that surface of cenosphere was coated by tio2 film, which thickness was 100 nm approximately and crystal model of the coated substance had already changed into rutile after calcinations at 850℃. For sepiolite, grain size of fiber was controlled by ball milling, when ratio of grinding media to material was 1:1.5 and the time of grinding was 3 hours, size distribution of sepiolite was uniform, the average size of sepiolite was 7.3μm. Experiment showed that heat-insulating filling with modified could gain better heat-insulating effect in coating, it had important significance to improve heat-insulating effect of coating. Lastly, formulation of coating was investigated by orthogonal design L9(33) and found that heat-insulating effect about sepiolite, hollow glass bead, titanium dioxide were descending. By furthering studies on orthogonal results and we got the better formulation: modified sodium silicate binder is 47%, hollow glass bead content is 12%, sepiolite is 19%, titanium dioxide is 10%, talcum powder is 5%, kaolin is 5%, auxiliary agent is 2%. Then, several conventional index of coating were tested according to relevant national standards and found it had better mechanical properties and effect of thermal insulating: adhesion of coating is between 0 and 1, impact strength is above 50 cm, thermal insulating effect is improved by 20℃than general coating. Many important indices such as thickness, viscosity, P/B and heat-resisting properties were studied and analysed of mechanics through general thermal analysi, SEM and many other methods.