High electrical conductivity waterborne dispersions of carbon black pigment

Cartridge³

2019

J Coat Technol Res

Self Cite

Section: Pigment Dispersionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High electrical conductivity waterborne inks for textile printing

Cartridge³

2019

J Coat Technol Res

Self Cite

“…During printing, the samples were held down using the vacuum plate attachment provided with the screen printing machine. The printing parameters were set on the basis of the results of a separate study by the authors (Muhammad Ali et al, 2019).…”

Section: Screen Printing Of Formulated Inksmentioning

confidence: 99%

“…In this study, the let-down stability of dispersions of non-printing ink grades of carbon black pigment was analysed. For this, the optimised binder-free pigment dispersions, that were prepared following a four-step method (Ali and Lin, 2018; Ali et al , 2019), were formulated into finished inks containing 100, 150 and 200 per cent “binder on the weight of pigment” (per cent BOWP). To assess the let-down stability, the viscosity profiles of the formulated inks were recorded and analysed for any signs of pigment aggregation.…”

Section: Introductionmentioning

confidence: 99%

Let-down stability and screen printability of inks prepared using non-printing ink grades of carbon black pigment

Faisal

et al. 2019

PRT

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Purpose This paper aims to analyse the let-down stability of the binder-free dispersion of non-printing ink grades of carbon black and to assess the screen-printability of the finished inks formulated thereof from these pigment dispersions. Design/methodology/approach Binder-free pigment dispersions that were prepared and optimised following a ladder series of experiments (reported in a separate study by the authors) were let-down with three different binders such that inks containing various amounts of a binder were prepared followed by a rheological characterisation immediately after formulation and after four weeks of storage. The screen printability of the inks that displayed considerable stability was assessed, so was the ink film integrity. Findings The pigment dispersions that were considered in the present study were generally found to be stable after let-down with different binders. This was indicated by the fact that the finished inks possessed a shear thinning viscosity profiles, after formulation and after storage, in most of the cases. Furthermore, the screen printability of the inks was also found to be good in terms of registration quality of a selected design. The structure of the ink film deposits on uncoated and binder-coated textile fabrics was also highly integrated and free from discontinuities. Originality/value Carbon blacks with very low volatile matter content and/or high surface area are generally not considered suitable for use in the formulation of printing inks. This is because of their generally poor dispersability and inability to form dispersions that remain stable over extended periods. This work, which is a part of a larger study by the authors, concerns with the stability of inks formulated from binder-free dispersions of such non-printing ink grades of carbon black. The major advantage of using such pigments in inks is that the required functionality is achieved at considerably low pigment loadings.

“…On the other hand, functional printing refers to a printing process that is desired to impart certain functionality to the substrate, for instance, electrical conductivity. Various aspects pertaining to the formulation of electrically conductive inks have been studied by the authors separately (Ali and Lin, 2018) (Ali et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Optimisation of screen printing process for functional printing

Faisal

et al. 2019

PRT

Self Cite

Purpose The purpose of this study is to explain the effects of screen printing parameters on the quantity of ink deposited and the print quality in the context of printing of functional inks. Both these aspects of printing are crucial in the case of conventional and functional printing. This is because, in the case of conventional printing, the quantity of ink deposit affects the color strength while in the case of functional printing, it directly affects the resulting functionality of the ink layer. Design/methodology/approach In this work, an automatic lab-scale screen printer was used to print functional inks on a paper board substrate. The printing parameters, i.e. printing pressure and squeegee angle were altered and the resulting effects on the quantity of ink that was deposited were recorded. The quantity of ink deposit was related to its surface resistivity. In addition, the quality of the print was also assessed by examining the design registration quality. Findings The authors found that altering the squeegee angle has a significant effect on the properties of the resulting ink deposit. More importantly, the authors found that the deflection in the rubber blade squeegee was greatly dependent on the initial angle of the squeegee at the start of the printing stroke. For each set value of the squeegee angle that was considered, the actual angle during printing was recorded and used in the analysis. A printing pressure of three bars and squeegee angle of 20° resulted in the maximum weight of ink deposit with a correspondingly lowest surface resistivity. Practical implications This study is envisaged to have considerable practical implications in the rapidly growing field of functional printing of flexible substrates including, but not limited to, textiles. This is because, the study provides an insight into the effects of printing parameters on the characteristics of a functional ink deposit. Originality/value Screen printing of flexible substrates is a well-developed and arguably the most widely used printing technique, particularly for textiles. Numerous studies report on the analysis of various aspects of screen printing. However, to the best of the knowledge, the effects of printing parameters on the characteristics of functional inks, such as electrically conductive inks, have not been studied in this manner.