| Polyurethane waterproof coating has good flexibility,tensile-strength, outstanding wearability, acid resistance, alkali resistance, low temperature resistance, excellent water resistance and toughness, these excellent characteristics make it be widely used.The Prepolymer of polyurethane is synthesized with MDI,polyether diols and polyether ternary alcohol in the paper,one-component polyurethane waterproof coating is synthesized with the prepolymer of polyurethane and additives such as the packing,plasticizer, chain extension agent, catalyst and so on. The factors which influence the film properties are discussed in detail including reaction temperature, reaction time, mass ratio of polyether diols and polyether ternary alcohol, NCO%, the content of catalyst etc, then the optimal reaction conditions is determined:the temperature of the synthesis of prepolymer is (80±2),? reaction time is 4 hour, m (N-220):m (330) is 8:1, NCO% is 5.5%, using dibutyltin dilaurate as catalyst and the content of catalyst is 0.3%.The component A of two-component polyurethane waterproof coating is synthesized with MDI,polyether diols and polyether ternary alcohol by using of pre-polymer method. Mixing the pre-polymer(component A)with component B composed of polyether,chain-extender, catalyst, packing etc. Two-component polyurethane waterproof coating is prepared after high-speed stirring. The factors which influence the film properties are discussed in detail including NCO%, the content of solid filler, the content of dibutyl phthalate and the content of petroleum resin, then the optimal reaction conditions is determined as follows:the temperature of synthesis of component A is (80±2),? time is 4 hour, NCO% is controlled at 4.5?5%; Component B, the content of solid filler is 30%, the content of dibutyl ,phthalate is 8%, the content of petroleum resin 8%; when the mass ratio of component A and component B is controlled at 1:2?1:2.5, the film can get better elongation at break and tensile-strength. |
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