Study On Synthesis Of Ester-soluble Polyurethane And Application In Ink

Ester-soluble polyurethane is the one that has been synthesized with polyol and isocyanate compounds, and ethyl acetate as solvent. It has not only overcome the toxic weakness of traditional solvent-based polyurethane, but also conquered the shortcomings of water-based polyurethane, which are the slower volatilization, the lower production efficiency and the bigger energy consumption. The purpose of this article is to research a kind of ester-soluble polyurethane, who acting as ink vehicles, we can form a new printing ink that owns better adhesion on non-polar substrate, such as plastic film. The feasibility study of fluorescent anti-falsification ink printed on plastic substrate is analysed preliminarily in this study, and the focus and difficulty is to solve the issue that ester-soluble polyurethane should content to the adhesion for non-polar substrate.The process of experiment can be approximately divided into the following steps:(1) The synthesis of polyester diols: Different molecular weight polyester polyols have been preparated in polycondensation reaction, with different types, different proportions of dicarboxylic acid and glycol, in a certain condition. Then the effect that the composition and ratio of raw materials acted on the adhesion properties was studied. The pH meter and differential scanning calorimetry (DSC) were applicated to analysis the hydrolytic stability and thermal stability of polyester diols. Finally, synthetic polyester diols were preliminary filtrated to cancel some wrong recipe.(2) Polyester diols, Which were preliminary filtrated, reacted with toluene-2,4-diisocyanate(TDI) by secondary chain-extension, in order to synthese ester-soluble polyurethane. Some factors were studied on the effect of reaction extent, such as reaction time, reaction temperature, the amount of catalyst. Other factors were researched in the effect on the adhesion of polyurethan, for instance, types and ratio of resin, the amount of TDI, types and amount of secondary chain extender, finally, the optimized formula was gained. Infrared spectroscopy has been used for analysing the extent of synthesis reaction quantitatively in the experiment.(3) The red polyurethane ink, which was prepared with ester-soluble polyurethane as ink binders, was selected as the object of study to analyse the relationship between the amount of ester-soluble polyurethane and the adhesion on plastic film. The results reveal that,when the amount of ester-soluble polyurethane (indicated by mass fraction) accounted for 39.7% of solid gross weight, the ink shows up a well adhesion.(4) Fluorescent anti-falsification ink was compounded with ester- soluble polyurethane as ink binders, and rare earth fluorescent complex as luminescent material. The luminescence properties of rare earth complexes were studied,especially whether the fluorescence quenching occurs. The results show that,the Fluorescence intensity was intensified with the increasing content of fluorescent agent in a certain concentration range, and the amino (-NH) of Polyurethane did not occur the fluorescence quenching.