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Pretreatment of fabric with a number of chemicals and auxiliaries is a prerequisite for inkjet printing. Owing to the rapidly increasing use of inkjet printing for textile fabrics, the study of the effects of process variables on various characteristics of the resulting print has drawn considerable interest recently. The purpose of this paper is to study the effects of different variables associated with the inkjet printing process on the quality of the resulting print. Specifically, the effects of chemicals and auxiliaries used in the pretreatment of the fabric prior to printing and factors such as steaming time were studies.

In the present study, which forms a part of a larger study by the authors, the influence of the nature of thickener, the amounts of thickener, urea and alkali, pH of the pretreatment liquor and the duration of steaming on ink penetration into the printed fabrics and the ink spreading across the fabrics was studied. The nature of ink penetration and ink spreading are known to have pronounced effects on the quality and, in turn, the overall appearance of the resulting print. A set of experiments based on a blocked 2^5–1 fractional factorial design with four centre points were conducted to evaluate the role of the aforementioned five variables. Ink penetration was quantified on the basis of the principles of Kebulka-Munk theory while ink spreading was analysed by image analysis.

Detailed statistical analyses of the experimental data obtained show that different thickeners perform differently and can have a marked influence on ink penetration and ink spreading. In the case of polyacrylic acid-based thickener, changing the levels of the factors has a marked effect on ink penetration and in-turn on ink spreading. In the case of polyacrylamide (PAM)-based thickener, on the other hand, the effect of changing the levels of various factors on the ink penetration and ink spreading is considerably less pronounced. In addition, PAM treated samples exhibited better performance in terms of ink penetration and spreading.

This study provides useful information for textile printers and highlights the importance of selecting the right type of thickener to make the printing process and the quality of the resulting print more predictable and controllable.

The purpose of this study was to optimise the dyeing conditions to achieve right-first-time dyeing in hard water. Owing to the persistent water scarcity for more than two decades now, the textile industry in Pakistan is forced to rely on high-mineral-content ground water for use in textile wet processing. Furthermore, the limited amount of municipal water that is at the disposal of the textile industry is also high in mineral content. Thus, on the large scale, water hardness has become an acute problem for the textile processor. In particular, in the dyeing process, water hardness is known to have crucial effects. However, to-date, no systematic study has been conducted on this aspect of textile dyeing.

In this study, 3² full factorial design was used to optimise the dyeing conditions to achieve right-first-time dyeing in hard water. Thus, cotton fabric was dyed with Red Reactive dye (of dyebath concentration at 5, 10 and 15 g/L) in prepared hard water (of hardness at 10, 40 and 70°dH), respectively. Analysis of variance, coefficient of determination (R²) and p-values for the models were used to evaluate the adequacy of the predictive models. The surface plots of the effects were studied to further examine the interactions of two independent variables. Derringer’s desirability function was used to determine the optimum levels of each variable.

Three levels for both independent variables generate second-order polynomial models to predict the colour strength, lightness, red/green, yellow/blue and total colour difference values of dyed cotton. The obtained predictive models point out the considerable influence of both water hardness and dye concentration on right-first-time dyeing.

Such a finding enabled the dye-mill to produce the correct shade at water hardness of 10°dH and 15 g/L dye concentration, without the need for corrective reprocessing.

The purpose of this study is to identify the most influential factors affecting the printing properties and print quality of digitally printed silk fabrics in terms of colour strength and fixation percentage.

In this study, five factors (concentration of thickener, concentration of urea, concentration of alkali, pH of pretreatment liquor and steaming duration) were investigated using a blocked 2⁵⁻¹ fractional factorial experiment. The type of thickeners [polyacrylic acid and polyacrylamide (PAM)] were considered as a block.

Linear models were obtained and statistically tested using both analysis of variance and coefficient of determination (R²), and they were found to be accurate at 90 per cent confidence level. It was revealed that concentration of alkali, concentrations of urea and pH of the pretreatment liquor had an increasing effect on colour strength, whereas concentration of thickener and steaming duration showed decreasing effect on colour strength of digitally printed silk fabrics. Furthermore, concentration of alkali, concentrations of urea had increasing effect on dye fixation percentage, whereas steaming duration showed decreasing effect on dye fixation percentage of digitally printed silk fabrics. In addition, PAM thickener based pretreatment recipe exhibited better printing properties for the digitally printing of silk fabrics.

The main influences and significant two-factor interactions were discussed in detail to gain a better understanding of the printing properties of digitally printed silk fabrics. The findings of this study are useful for further optimisation of pre- and post-treatment processes for digital printing of silk fabrics.

The purpose of this study is to investigate the utility of carbon black containing coating formulations that are conventionally used for pigment printing of textiles in fabricating electrically heated fabrics.

Specifically, electrical and thermal characterisation of the coating system was carried out to establish the feasibility of the system for use in the manufacturing of flexible heating elements on textile substrates. The coating formulations were applied via a simple padding technique followed by stitching the electrodes using a conductive yarn.

The heating elements of different sizes thus produced showed Ohmic behaviour as a resistor and attained a targeted temperature difference of up to 40°C within the applied voltage range. A prototype heater was also produced, and thermography results showed uniform heating and cooling of the heater that was incorporated into a jacket.

The proposed method is envisaged to be very practical for the realisation of completely textile-based heating elements of different shapes and sizes. Furthermore, the proposed manufacturing method can be used to convert conventional ready-made articles of clothing into heated textiles for various applications.

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.

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.

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.

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.

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.

Among various metal oxide nano particles, MgO NPs and ZnO nanoparticles (NPs) in particular are gaining increasing attention due to their multifunctional characteristics, low cost and compatibility with textile materials. Each type of nanoparticle excels over others in certain properties. As such, it is often crucial to carry out comparative studies of NPs to identify the one showing higher efficiency/output for particular applications of textile products.

In the investigation reported in this paper, ZnO NPs and MgO NPs were synthesised via sol-gel technique and characterised. For comparative analysis, the synthesised NPs were evaluated for multiple properties using standard procedures before and after being applied on cotton fabrics by a dip-pad-dry-cure method.

XRD and FTIR analyses confirmed the successful synthesis of ZnO and MgO NPs. Homogeneous formation of desired NPs and their dense and uniform deposition on the cotton fibre surface were observed using SEM. ZnO NPs and MgO NPs coatings on cotton were observed to significantly enhance self-cleaning/stain removal properties achieving Grade 5 and Grade 4 categories, respectively. In terms of ultraviolet (UV) protection, ZnO or MgO NP coated fabrics showed UPF values of greater than 50, i.e. excellent in blocking UV rays. MgO NPs exhibited 20% cleaning efficiency in treating reactive dye wastewater against ZnO NPs which were 4% efficient in the same treatment, so MgO was more suitable for such type of treatments at low cost. Both NPs were able to impart multifunctionality to cotton fabrics as per requirement of the end products. However, ZnO NPs were better for stain removal from the fabrics while MgO NPs were appropriate for UV blocking.

It was therefore clear that multifunctional textile products could be developed by employing a single type of cost effective and efficient nano particles.

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.

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.

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.

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.