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Development and scale‐up of thermoplastic poly(ether‐ester) glycol polyurethanes for flexography
Author(s) -
Ferreira Roberta,
Dias Rafael,
Laqua Letícia,
Pavan Felipe,
Marangoni Cintia,
Machado Ricardo
Publication year - 2021
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.51273
Subject(s) - materials science , differential scanning calorimetry , castor oil , gel permeation chromatography , polymer chemistry , fourier transform infrared spectroscopy , thermoplastic , polyurethane , solvent , polymer , thermoplastic polyurethane , chemical engineering , ether , rheology , intrinsic viscosity , composite material , organic chemistry , chemistry , elastomer , physics , engineering , thermodynamics
This study presents an experimental essay on the production of thermoplastic polyurethanes for flexographic printing ink applications. Four formulations were obtained by step‐growth polymerization reactions having the pre‐polymer 4,4′‐diphenylmethylene diisocyanate and Voranol 2120 L® catalyzed by dibutyltin dilaurate as common ground. In the chain extension step, ethanol or ethyl acetate was used as solvent, and the use or not of castor oil as a chain extender in addition to hexanedioic acid and 2,2′‐oxydi(ethan‐1‐ol) was evaluated. The chemical structures of the synthesized thermoplastic polyurethanes (TPUs) were evaluated by Fourier transform infrared spectroscopy, 1 H NMR, gel permeation chromatography, differential scanning calorimetry, and rheological features were assessed by density and viscosity analysis. The TPU resins were used to produce flexographic printing inks and further tested by friction, adhesion, gloss, and Gardner viscosity essays. It was found that the castor oil presence enhanced ink viscosity in 66% (from 26,790 to 44,440 Pa s) as well as improved strength. Formulations using ethanol as solvent showed the best results. The experiments were carried in a 250 ml reactor and then, scaled up to 2000 ml, keeping the power transfer per unit of volume constant at around 0.8 W/L. The analytical results from the larger scale were as good as the obtained in scale one, showing promising application.