Partial substitution of nitrocellulose by polyurethane resins in flexographic ink concentrates

Abstract

The properties of flexographic inks obtained by the partial replacement of nitrocellulose (NC) resin with different amounts of polyurethane (PU) resins were evaluated for the statistical planning of mixtures to develop an optimum ink formulation. The formulations were developed using a statistical tool and they were found to present properties predicted by the tool. The results indicate that the substitution of the NC resin with PU resins leads to increased resistance of the ink film to delamination. The system obtained with the partial substitution of NC with PU has higher lamination bond strength than the pure NC‐based system. The ink films of the formulations NC‐based and NC/PU‐based were evaluated by spectroscopy UV–vis, both inks have similar transparency of greater than 95% above 575 nm. When exposed to water, milk, and UV light, ink surfaces showed similar behavior in the atomic force microscope, Fourier‐transform infrared spectroscopy, and UV–vis analysis. However, ink formulations with higher PU contents underwent higher photodegradation. Other properties such as the viscosity ink, gloss, coating strength, color, adhesion, and blocking of the NC/PU‐based ink film did not vary significantly when compared to those of the standard ink produced exclusively with NC resin.

Development and scale‐up of thermoplastic poly(ether‐ester) glycol polyurethanes for flexography

“…These values are close to the obtained with the Brookfield method. Furthermore, these values of viscosity are relatively close to the ones of commercial PU resins (named PU 1 (5.25 Pa s) and PU 2 (1.15 Pa s)) recently evaluated for flexographic use 19 . It can be noticed that resin IV and PU 1 have higher viscosities than the others.…”

“…The bands related to O─H, C─H, and C─O bonds, were also identified for the commercial PU resins used in the study of nitrocellulose replacement 19 . Moreover, the absence of urethane bands is seen in its FTIR spectra.…”

“…Likewise, another research has been performed towards the replacement of a nitrocellulose resin by two PU resins containing different solid contents. It was pointed out that the partial replacement was done increasing the lamination bond strength of the produced flexographic ink, besides keeping the standard physicochemical properties 19 …”

Functionalization of Nitrocellulose Film by AB-Type Click Polymerization: Methods and Property Enhancements

“…It has a glucopyranose repeating unit containing varied numbers of nitro groups and is classified based on the degree of nitration on cellulose units. , Usability and areas of application depend on the degree of nitration and nitrogen contents . Nitrocellulose with nitrogen content >12.5% is used as a major component of propellants for fireworks, rockets, guns, etc. , On the contrary, NC with nitrogen content <12.5% can be used in coatings, microelectronics, lacquers, inks, purifying membrane, adhesives, wound dressing applications, etc. ,− For example, the nitrocellulose membranes with a lower percentage of nitrogen has been used as a strip for diagnosis tests , and wound healing material . For other applications, Mujawar et al fabricated nitrocellulose membrane pads in cameras and confocal laser scanning microscopes, where the transparency of the material is a key factor.…”

Preparation and Characterization of Polyurethane/Nitrocellulose Blends as Binder for Composite Solid Propellants

“…Indeed, it is found that there was certain hydrogen bonding between nitrocellulose and polyurethane network, and with the increase in the content of nitrocellulose in the blend system, the hydrogen bonding in the polymer admixture system were strengthened and the mechanical properties were improved [25]. During these last two decades, different research teams [25][26][27][28][29][30][31] mixed the polyurethane with NC in order to improve the mechanical and energetic properties. However, to the best of our knowledge, the investigation of compounding polyurethane based on HTPS with NC has never been carried out.…”