Synthesis and Properties of Hydroxyl-terminated Hyperbranched Poly Isocyanurate-ester Retanning Agents

AB2 monomer was synthesized by Michael addition ofdiethanolamine (DEA) and methyl acrylate (MA). Then thehydroxyl-terminated hyperbranched poly isocyanurate-esterwith different generations (HPICEs) which were named asHPICE-I, HPICE-II and HPICE-III, were prepared respectivelyvia three-(2-hydroxyethyl) isocyanurate (THEIC) and AB2monomer in which THEIC was used as the core and AB2monomer as the branching unit. The structure and mass ofHPICEs were characterized by Fourier Transform InfraredSpectra (FT-IR), nuclear magnetic resonance hydrogen spectra(1H-NMR) and gel permeation chromatography (GPC). HPICEswere applied in the retanning process of wet blue leather. Theresults show that when the dosage of HPICEs retanning agent is3% (basing on the weight of wet blue leather), the properties ofleather retanned with HPICE-III are the best compared withthose retanned with HPICE-I and HPICE-II. The thickeningpercentage of the back and belly were 14.88% and 20.54%,respectively. Compared with that of leather retanned with RST,a kind of acrylic retanning agent widely used in the market, thetearing strength, tensile strength and cracking strength of theleather retanned with HPICE-III are increased by 53.31%, 65.69%and 85.28% respectively. All the leather samples retanned byHPICEs exhibited better dry rub fastness but worse wet rubfastness than that retanned by RST. In addition, the samplespresent better surface properties as well.