The Preparation Of Green Straw-based Thermal-insulated Coating

In this paper, one kind of water-based straw-based green coating with thermal insulation was prepared. With acrylic emulsion as the base material, rutile titanium dioxide, talc, kaolin and straw ash like pigments and fillers, and cooperated with silicon-based mesoporous material and a number of additives. The process of thermal-insulated coating preparation was determined, the optical properties and thermal-insulated properties were checked and results indicated good performance.Straw ash used in the experiment was normal corn and rice stalks, and corn stalks was gray white powder and rice straw ash was light purple powder after heat treatment at 600℃for 8 hours. Silicon-based mesoporous materials was prepared by sol-gel method with P123 template, Tetraethyl orthosilicate as silicon source, after mixing, aging, filtration, washing, and then calcined at 550℃for 6 hours. There were two steps to prepare the thermal-insulated coating:firstly, pigments and related additives mixed with water,and mixed the emulsion with film-forming additives. Secondly, they were mixed to prepare thermal insulation coatings. Bysides, the agent was required with a certain amount of ammonia to add to make slurry into the alkaline solution which was the best way to make the liquid thicker.After preparation of thermal-insulated coating, exterior coating should be suitable for the national performance on standard tests related to basic performance coatings eligibility, including drying time, opacity, tensile strength, water resistance, alkali resistance and stain resistance properties. The test of thermal-insulated properties was mainly done by UV/visible/infrared photometer reflectance,the designed testing device of thermal properties and solar simulator to characterize the heat reflection.The thermal-insulated coating showed good construction performance, and could brush two barrier-free well. There was no lumps in containers,and it was uniform after stiring. Dry time was less than 2 hours, dried coating was smoothy with no pinhole,no craters or other defects, and good hiding power. The coating was suitable for the performance requirement of exterior wall coating, and showed good tendsile strength, water resistance, acid and alkali resistance, and also good resistance staining performance and weatherability. As a thermal-insulated coating, it showed excellent thermal insulation, and the largest reflectance more than 90% in visible region, the average reflectance as high as 85%. In the thermal performance comparison experiments, the maximum measured temperature difference between inside and outside the box was 66℃. We also furtherly checked the straw-based thermal-insulated coating with high thermal reflectivity by the solar heat reflection set-up.Preparation of this new water-based heat-insulation coating to realize the comprehensive utilization of waste, energy saving, with good market prospects.