The Synthesis Of Self Emulsifying Hyamine Cationic PU And The Application

The main purpose of this study is to synthesize self-emulsified ionic polyurethane(PU), to find a better condition in prepolymerization, chain extend and emulsion reaction, to obtain a stable PU emulsion. This thesis is mainly to settle the choice of reaction conditions, to find the economical, widespread synthetic process, and finally synthesized the stable cationic PU emulsion.In addition, because of the weak of water resistance and solvent resistance in water borne polyurethane materials, the cross linking modification method is the important means to solve this problem. In this paper, castor oil was used to modify PU emulsion, and successfully synthesized the inside cross linked PU. On the other hand, using renewable resources instead is fit for the social development.The cationic PU emulsion, which contained hyamine, was synthesized by polyether diol and diisocyanate. The experiment results showed that the properties of PU emulsion was much better and the reaction was more easily controlled when the ratio of—NCO and—OH was 2:1-3:1 with PEG (400) and TDI as the main material, acetone as solvent. And the reaction rate increase obviously along with elevating temperature and raising the dosage of catalyzer. When the temperature is 60℃, the dosage of catalyzer is 1% in mass fraction of system, the system synthesize stably and speedily.The chain extender of cationic PU is a kind of catalyzer to the reaction. The experiments concluded that the reaction was stable and PU emulsion was good when it was taken at normal temperature, the amount of MDEA was 5% of the system and the chain extender was dropped hungrily.Emulsion course was a very important and hard step. The condition of the emulsion reaction was a key to the success of WPU synthesis. According to a large number of experimental results, the emulsification course should be taken under low temperature and low mixing speed. Thus it would be propitious to obtain stable latex.Further more, due to the lack of waterproof of PU, we used castor oil partly replacing polyether polyols in the PU. There was a crosslinked structure in PU so as to improve waterproof of the material. The results showed that the addition of CO. can really modify the property of PU. The modification was inconspicuous at low cross linked point. While at a relatively high cross linked point, the PU was obviously modified by CO.. When the mole ratio of PEG and CO. was 7:3, the PU emulsion could achieve a good state, and the properties were also high.We mixed the WPU and API, determined the adhesive properties and concluded that the bonding strength was better than simple API adhesive when the ratio of API and PU emulsion was 5.4:2.3-5:2.9.