The Synthesis And Research Of Polyurethane Disperse Violet H-FRL

In the field of dyes, common dyes (reactive dyes excepted) are usually fixed to material by electrovalent bond, hydrogen bond or the hydrophobic interaction. The combination is not strong, so it is easy to fade. But the polymerizing of small molecule dye to polymeric dye can effectively resolve the problems above.In This paper , a kind of polymeric dye is synthesized with 2,4- tolylene diisocyanate(TDI), triethyleneglycol(TEG) and disperse violet H-FRL by chemical modification. The polymeric dye is separated and purified with acetone and ethanol. The structure of the polymeric dye is characterized by FT-IR and UV-VIS, and The thermodynamic stability are obtained from the analysis of the TG. The result of FT-IR shows that the polymeric dye prepared has the characteristic absorption peak of polyurethane and polyurea. The UV-VIS shows that the absorption peak of polymeric dye in the visible region are present to 548nm and 592nm, which have a change to low wave, and there appears a new absorption peak at 508nm. The curve of TG shows that the decomposition temperature of the polymeric dye is 230℃.The paper also researched the factors which influence the yield, such as react temperature , the variety and dosage of solvent, addition sequence and react time. Optimization of the synthetic conditions is also researched. The result shows that the reaction between disperse violet H-FRL and 2,4-TDI is controlling step. It is abled to gain a yield over 80% with DMF as solvent , while the volume ratio between solvent and TEG is 30:1, the addition sequence is adding dye first and adding TEG second, and the first step reacts 6 hours at 70℃, the second step reacts 2 hours at 50℃.