Preapration Of Mixed Ether-based Elasci Plyrhae Sealant

In this paper, we synthesis a series of different performance polyurethane sealant by using of diisocyanate (MDI) and polyether polyols which are some various combinations of several polyethers with different molecular weight as raw materials.(1) According to the study of a series of reactions, when the reaction temperature was 85±5℃, the time of prepolymerization was 3h, the required content of the prepolymer NCO can be prepared, and in this way, excellent two-component polyurethane sealant also could be prepared.(2) When polyethers of different molecular weight were mixed, the compatibility of the urethane prepolymer of the soft segment and hard segment increased with the increase content of small molecular weight polyether, and its viscosity and tensile strength have been increased significantly, but the elongation at break decreased.(3) When polyether binary glycol and polyether ternary glycol were mixed to prepare the sealant, with the increasing proportion of polyether ternary glycol, the viscosity of polyurethane prepolymer decreased, the tensile strength also decreased, but the elongation at break increased.(4) Using different blocking agent to terminate the polyurethane prepolymer can prepared polyurethane sealants of different curing time, the curing time of sealant can be adjusted at different seasons, which was easy to operate.2 Preparation of silane terminated polyurethane sealant(1) The factors of the silane terminated curing one-component sealant were studied. The curing time was decreased with the dose of the catalyst.(2) Use coupling agent of different functionality for the termination of polyurethane prepolymer, an d found that the tensile strength and sealant viscosity got larger with the increase of the use of three alkoxy silane ratio, and elongation at break had a great decline.