| The water fluorescent falsification-resistant ink is not only effective, but also environmental. Its development and application are payed attention to by people more and more. A waterborne polyurethane emulsion was by prepolymerization in this paper. Based on WPU preparation, we prepared a kind of top grade water fluorescent falsification-resistant ink. Its various properties were up to the request of falsification-resistant. The major contributions of this paper are as follows:1. The reaction condition was determined and the effects of dimethylolpropionic acid (DMPA) content, the ratio of -NCO/-OH, the reaction temperature, the reaction time, the amount of catalyst, the category of neutralizer and neutralization of hydrophilic extender on the properties of emulsion and adhesive were researched. The optimal synthesis parameters of the waterborne polyurethane are that the temperature of prepolymerization reaction is 70℃, the time is 70 min; the chain extender reaction time is 40 min at about 78℃; the temperature of neutralization reaction is 35~40℃and the emulsion reaction was at the room temperature; the chain extender reaction time is 40 min at about 78℃; the emulsion was solidified after 60 min at 120℃. The category of neutralizer was TEA. The ratio of -NCO/-OH was 1.8. The content of DMPA was 5.5 %. The category of neutralizer was TEA and the PH was 7~8.2. Based on WPU preparation, we prepared a kind of top grade water fluorescent falsification-resistant ink. The effects of fluorescent agent content on properties of the ink. The viscosity and fluorescence intensity of ink is increased when the content of fluorescent agent is increased. The cost was increased when the content of fluorescent agent was increased. In order to obtain an effective and cheap fluorescent falsification-resistant ink, the content of fluorescent agent was determinated as 2.5 %.
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