| The water-borne polyurethane is a binary colloidal system which is based on water asdispersion medium. The comparison between the solvent polyurethane and the waterbornepolyurethane (WPU), WPU has overriding advantage for its innoxious, free from contam-ination and less flammability. Its disadvantage is that the drying time for waterbornepolyurethane is longer than the time of solvent polyurethane, when they have the same solidcontent. So, increasing the solid content is one of the most effective methods to solve thisproblem.In this paper, waterborne polyurethane containing sulfonic groups was synthesized onacetone method by using isophorone diisocyanate (IPDI) and polytetramethylene glycol(PTMG) as raw material, ethylenediamine sodium sulphonate (X506) as hydrophilic chainextender. The optimal weight of X506 isω=18%, which determined by the solid content,water absorption, viscosity, peel strength and tensile strength tests. And the best reaction timeis 7~10 min determined by observing the appearance and by measuring stability of emulsion.Water-borne polyurethane containing sulfonate is confirmed by infrared spectroscopy (FTIR).On the basis of the above experimental condition, waterborne polyurethane emulsion withmore than 50% of solid content which is containing both carboxylic and sulfonic groups isprepared, in which dimethylol propionic acid (DMPA) and ethylene diamine sulfonate (X506)is as hydrophilic chain extenders. The experiment results show that all performances ofemulsion is relatively good when the ratio of DMPA and X506 is 1:1. The solid content of theemulsion can be up to 51.39% when the ratio is 3:1, but general performances are not verywell. The solid Content of WPU that is synthesized from DMPA and X560 is higher than thatis synthesized from DMPA or X560 alone, and it is stable and low probability of occurrenceof gel. Only flaw is high viscosity of emulsion. |
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