Preparation And Application Study On High Strength Polyurethane Waterproof Coating

The passenger lines has been developed rapidly in our country because of the overall plan of the line named "eight vertical and eight horizontals" and intercity travel system in the densely populated and economically developed regions. So the high performance waterproof coating must meet the railway waterproof requirements with the development of passenger lines.With the development of the city's construction, urban construction will also be modernized. In order to increase the green vegetation coverage, it is particularly important to get on green roof in the city. One of the most important work in roof greening is waterproof project. Because the planting plants has the ability to puncture, it will cause significant losses to the owner once pierced the waterproof layer. Nowadays, waterproof roll are major waterproof membrane. Its defect is which seams are not close in actual application. Therefore, it is necessary to research and develop a high performance waterproof material and applied it to roof greening and waterproofing of railway bridge.In this paper, according to polyurethane waterproof coating development,performance and new use, the preparation and its mechanism, methods and technical means of Low harmful, high performance high-strength polyurethane waterproof coating were be researched to meet the requirements for new applications of passenger lines and roof greening.The research results show that the mechanical properties of the coating are better when the total NCO /-OH value of prepolymer A component is 5 and the first batch NCO/-OH value is 2.5. The mechanical property of the coating film improved when the amount of the transparent talc powder is increased and the amount of the chlorinated paraffin is decreased in the range of transparent talc powder 10-25 parts and chlorinated paraffin 20-35 parts. The tensile strength of the coating film is increased and elongation at break of the coating film is decreased when the amount of the transparent talc powder is increased and the amount of the plasticizer is decreased in the range of transparent talc powder 25-40 parts and plasticizer 15-30 parts. While the relative weight amount of each raw material is that talc powder is 35, chlorinated paraffin is 10, DOP is 20 and antifoaming agent AC300 is 4, the tensile strength and the elongation at break of high strength waterproof coating is 7.46 MPa and 586.24%. The try to use MDI instead of TDI also be studied for low free TDI high-strength waterproof coating. In the present study, a double-crosslinking mechanism of polyurethane was obtained by adding isocyanate in a stepwise manner in order to obtain the high-strength, high-elasticity waterproof coating.The results showed that the tensile strength of the coating is stronger and the puncture resistance is stronger. Compared with the common waterproofing membrane, the puncture resistance of high tensile strength polyurethane waterproof coating is excellent and better than that of the most waterproofing membrane. In order to shorten the testing time of plant root puncture resistance, it is meaningful to use Forsythia suspense as a test plant to carry out rapid root penetrating test and observe its results.