Ink‐jet printing of cotton with natural dyes

Four natural dyes, annatto, cutch, pomegranate fruit rind, and golden dock, were used as colorants for the preparation of water‐based ink‐jet inks for digital textile printing. The physical and rheological properties (pH, conductivity, surface tension, and viscosity) of the inks were measured over a period of 90 days for the evaluation of ink stability and suitability for ink‐jet printing. The inks were found to be suitable and were used for the digital printing of cotton fabrics. The prints were subjected to wash, light, and rub fastness tests and colour measurements. Colour consistency and fastness results, especially after fixation, are comparable with those of synthetic dyes, which paves the way for the production of environmentally friendly ink‐jet inks using natural dyes for the digital printing of cotton through the formulation of suitable printing techniques.     

Synthesis,characterization, and application of hetarylazo disperse colorants: Preparation and properties of ink-jet inks with active agents for polyester printing

The synthesis and characterization of two hetarylazo disperse colorants are described. These compounds were used for the preparation of ink-jet inks with and without active agents for polyester printing. The viscosity, conductivity, surface tension, and pH of these inks were studied over a period of time and discussed with respect to their structure and the active agent content. The particle size and particle size distribution of a representative ink containing a new synthesized hetarylazo compound were measured. All the prepared inks were proved to be suitable for ink-jet printing in terms of their particle size. Viscosity , surface tension, conductivity, and pH values of all inks, with and without active agent, were monitored over a period of 90 days and were related to the ink stability. The same properties were measured for an ink preparation with a commercial dye for comparison. The inks containing the new synthesized dyes were found to be more advantageous regarding most of the above properties, i.e., surface tension, viscosity, and conductivity. Contrarily pH values of all the preparations were unacceptable for ink-jet inks. The ink compositions containing the new synthesized compounds were applied by exhaustion (dyed) on polyester fabric. Fastness properties of the dyed polyester samples were excellent to very good in most cases. Color measurements of the dyed fabric were also performed. A qualitative determination of the aroma-active agent adsorbed on the fiber by the exhaustion method was achieved by the GC-MS method. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The influence of ink viscosity,water and fabric construction on the quality of ink‐jet printed polyester

This paper is concerned with the quality of lines and disperse ink in printing patterns on different untreated polyester fabric constructions. The lines running in the weft and warp directions were printed on polyester fabric constructions, and printing accuracy was assessed. Ink spreading is one of the important factors that influences the ink distribution. Thus, in order to acquire satisfactory ink‐jet printing products, it is essential to control the spreading of ink on the polyester fabric. To meet these conditions, a series of chemicals (disperse dye 5.01 wt%, PVP‐K30 0‐2 wt%, DEG 5‐20 wt%, water 64.17‐79.17 wt%, etc) with different mass fractions was used to prepare disperse ink. The jetting behaviour of ink was related to its surface tension and viscosity, which was characterised by an automatic surface tensiometer and rotational viscometer. Line profile was used to evaluate the printing effect. Low field nuclear magnetic resonance and three‐dimensional super depth digital microscopy were used to reveal the relationships between the state of water, ink diffusion behaviour and printing sharpness. The results showed that increasing ink viscosity or decreasing free water content is advantageous to improve the sharpness of the printing pattern. The effects of fabric structural parameters on line image quality are discussed. The printing quality was closely related to the weight and structure of fabric. The heavy weight fabrics had accurate print pattern sharpness. The fastness test results showed that the ink printing pattern had good colour fastness.     

Digital and conventional printing and dyeing with the natural dye annatto: optimisation and standardisation processes to meet future demands

The plant colorant annatto was investigated to determine its potential use as a natural dye for conventional and novel textile applications. Alum was selected as a mordant. Different techniques of mordanting and a broad set of variations in the dyeing recipes were applied to achieve optimisation and an improvement in colour fastness properties. Quality control of all dyeings was performed using standard fastness tests and colour measurements. Printing of cotton fabrics was also achieved with annatto using the flatbed screen‐printing technique. Measurement of the rheological and physical properties of the annatto printing paste confirmed its stability and suitability for conventional printing. Fastness properties of the conventionally printed annatto fabric were also measured. A novel water‐based digital printing ink using annatto was prepared and applied to cotton fabric using a digital printing application. The physical properties of the annatto ink‐jet ink were also measured. Wash, light and rub fastness properties of the annatto digitally printed fabric were determined and compared with those of conventional printing methods. The results were promising for annatto as a natural colorant, which possibly paves the way for the development of a new range of natural environmentally friendly dyes.     

Single‐phase ink‐jet printing onto cotton fabric

The current commercial application of ink‐jet reactive inks to cotton fabrics requires pretreating with pad liquor containing a thickener, urea and alkali prior to printing. In this study, attempts have been made to develop a reactive ink‐jet print in a single‐phase process by adding an organic salt to the ink formulation and hence removing the need to pretreat fabrics. This approach utilises inks containing both a reactive dye, in this case Procion Red H‐E3B, and an organic salt such as sodium formate, sodium acetate, sodium propionate or tri‐sodium citrate. The behaviour of a novel reactive ink formulation for ink‐jet printing on to cotton fabric was evaluated at different pH vlaues. The results at optimum pH indicated that printed non‐pretreated fabrics with ink containing organic salts exhibited a higher level of reactive dye fixation than printed pretreated fabric containing no organic salt ink. The yielded prints demonstrate excellent colour fastness to washing and dry/wet crocking properties. The light fastness of the printed fabrics was improved by adding an organic salt to the ink formulation.     

Syntheses of polymeric dispersants for pigmented ink‐jet inks

Drop‐on‐demand ink‐jet inks made from dyes usually show poor light fastness and poor water fastness. Therefore, many researchers have introduced pigments into ink‐jet inks to overcome the defects of dye‐based ink. Pigmented ink needs sophisticated technology which disperses the pigments stably in low viscosity. Thus, adequate dispersants are essential to achieve stable dispersions of pigments for ink‐jet inks. This study describes syntheses of dispersants, properties of formulations and comparisons of performance with an existing ink to assess their suitability for commercial application.     

Properties of ink‐jet printed,ultraviolet‐cured pigment prints in comparison with screen‐printed,thermo‐cured pigment prints

A collection of printed fabrics for men’s shirts was designed and prepared using computer‐aided design/computer‐aided manufacturing technology. The colours for designs were ink‐jet printed on cotton fabrics with pigments and ultraviolet‐cured. These prints represented the target colours for subsequent flat‐screen printing, which was performed using pigment printing pastes and thermal curing. For an exact transfer of colours of the ink‐jet‐printed standard into the screen‐printing process, a computer recipe prediction method was used. A comparison of colorimetric parameters of fabrics printed with both printing techniques shows minimal and acceptable differences in the CIELab colour values. A comparison of colour fastness properties proves that very good colour fastness is achieved on the pigment‐printed fabrics produced with both printing techniques. The flat‐screen‐printed fabrics show better colour fastness to washing, perspiration and rubbing, while ink‐jet‐printed fabrics show better colour fastness to dry‐cleaning and light. The fabrics printed with both printing techniques have high rigidity and non‐elastic properties. The mechanical and physical parameters are strongly dependent upon the amount of the dry substance of the printing media applied on the cotton fabric surface, which is higher on screen‐printed fabrics. The ink‐jet‐printed fabrics show better air permeability than flat‐screen‐printed fabrics.     

Synthesising polymeric dispersants to apply to carbon black pigmented mill bases for use in ink‐jet inks

Dyes are an important component of drop‐on‐demand ink‐jet inks and are commonly used in desktop printers. While they offer bright, vivid colour, these dyes exhibit poor light and water fastness. To combat this, researchers have started using pigmented ink‐jet inks instead of dye‐based inks to improve light and water fastness, but the pigments are insoluble in ink vehicles. To use pigments, dispersants must be applied; however, this is a delicate process because the properties of the dispersant substantially affect how the pigmented mill base must be prepared. In this study, polymeric dispersants are synthesised based on the properties and ratios of monomers and the molecular weights of polymers. In total, 14 types of polymeric dispersants are synthesised and examined, with special attention paid to the dispersing properties of particle size reduction and the stability of the pigmented mill base used to prepare drop‐on‐demand ink‐jet inks. This study describes the synthesis of the dispersants in terms of their suitability for commercial application.     

Preparation of pigmented ink‐jet ink by a combination of surface treatments and synthetic dispersant

Drop‐on‐demand ink‐jet inks prepared from dyes usually show inadequate light and water fastness. Thus, in our previous paper, we studied black pigmented ink‐jet inks with the aim of overcoming the drawbacks of dye‐based ink by employing a variety of synthetic dispersants with gas black. In this study, pigmented ink‐jet inks were prepared by a combination of the synthetic dispersant and the surface treatments of a furnace black that is more common than gas blacks. The results of this study show that the surface treatment of the furnace black and the use of the synthetic dispersant are useful in the preparation of ink‐jet inks and endow them with properties that are comparable with those of commercial ink‐jet inks.     

Rheological Characterization of Aqueous 3Y‐TZP Inks Optimized for Direct Thermal Ink‐Jet Printing of Ceramic Components

Aqueous 3Y‐TZP inks with solid contents of 22 and 27 vol% were used for fabricating three‐dimensional ceramic components by the direct ink‐jet printing process (DIP). The DIP fabrication was realized using a thermal ink‐jet (TIJ) printing system. Despite the different physical properties of the inks, both inks were successfully ejected and deposited. To define the optimum window of the ink properties required for a stable printing operation, both ceramic inks as well as a typical TIJ ink were characterized in terms of particle size distribution, zeta potential, viscosity, surface tension, and the inverse Ohnesorge number (Oh^?1). Moreover, single drops of all inks were deposited and analyzed by scanning electron microscopy (SEM) to examine the form and integrity of the ejected drops. Demonstration objects (a base with curved channels and a sample molar tooth) were DIP fabricated using both of the ceramic inks. These objects show the potentials of the DIP process for ceramics manufacturing particularly by using TIJ printing systems.     

Pretreatment of silk fabric surface with amino compounds for ink jet printing

This research studied pretreatments of silk fabric with amino compounds for ink jet printing. The pre-treating solutions were serine, glycine, aspartic acid, sericin, chitosan, and a commercial pre-treating chemical called Sanfix 555. Both untreated and treated fabrics were printed with in-house formulated pigmented inks and later steamed to fix the ink on the fabric surface. The pretreatments containing the amino compounds improved hydrophilicity of the silk fabric with the exception of chitosan. The color gamut from sericin, chitosan, and Sanfix 555 pretreatments was wider than that from the amino acid pretreatments. The chroma of the cyan color was most improved. The fabric, after pretreatment with sericin, showed a significant improvement in dry crock fastness while wet crock fastness was improved by serine and glycine. The chitosan slightly improved both dry and wet crock fastness. Wash fastness of all pretreated and printed fabrics including untreated and the printed fabrics was excellent because the pigmented ink was formulated with pigment and binder. Bending stiffness of the silk fabrics after chitosan pretreatment was significantly higher than those with other pretreatments. The ink penetration in sericin and chitosan padded layers was shallower than those for amino acids, enhancing ink deposition on the fabric surface. The amino compound pretreatments held and fixed additional ink on the fabric surfaces resulting in a wider color gamut of the inks.     

A custom ink‐jet printing system using a novel pretreatment method

A low‐cost and environmental‐friendly direct dye‐based ink‐jet printing system was developed. A novel ink‐jet pretreatment method was employed, in which the cationic fixing agent, Matexil FC‐ER, was applied as the colourless fixing ink and applied only on image areas of the fabric by ink‐jet printer. It was found that this new pretreatment method could more effectively enhance the colour strength and improve the wash fastness (greyscale ≥ 3) when compared with traditional exhaust application. The cross‐staining of non‐image areas of fabric was also apparently decreased using this new method. The light fastness of ink‐jet pretreated samples was slightly reduced as the presence of Matexil FC‐ER made dyes more sensitive to light.     

Some properties of a thickener for preparing inkjet printing ink for nylon carpet

The properties of a thickener for nylon carpet inkjet printing are presented in this work. A water-based ink was prepared from polyacrylate-based thickener. The physical and chemical properties of the polyacrylate-based thickener used for preparing the inkjet printing ink, as well as its printing effects on carpet, were investigated. Before printing, the properties of the ink, including its surface tension, electrolyte resistance, storage stability, and percentage removal, were investigated. After printing, the efficiency of coloration of printed carpet and the fastness of printed carpet were studied. The results concerning the surface tension and percentage removal of printing ink show that the polyacrylate-based thickener printing ink is suitable for nylon carpet inkjet printing. Meanwhile, its storage stability and electrolyte resistance make it suitable for printing. The efficiency of coloration of printed carpet and the fastness of printed carpet satisfy the requirements of application at appropriate ink concentration and viscosity.     

Resistance variation of conductive ink applied by the screen printing technique on different substrates

This research study focuses on the application of conductive ink by the screen printing technique to evaluate the potential of creating printed electrodes and to investigate the effect of washing upon electrical resistance and flexibility. Two conductive inks were applied by a conventional screen printing method on four different textile substrates, 100% cotton, 50%/50% cotton/polyester, 100% polyester and 100% polyamide. The inks were also applied on a multifibre fabric. Atmospheric plasma treatment was applied to improve the adhesion to the samples, and the resistance values were compared with those of non‐treated samples. The values were measured before and after cleaning and washing tests, which were performed to simulate domestic treatment for garments to predict the behaviour of the inks after normal usage of the fabrics. Comfort properties like stiffness of the fabrics were also evaluated after five and 10 washing cycles. It was observed that PE 825 ink forms a thicker film on the fabric surface, contributing to the loss of flexibility of the textile. However, PE 825 ink also produced the best results in terms of durability and lower values of resistance. Polyamide fabrics lost their conductive property after five washing cycles due to weak bonding between the ink and the fibres, whereas cotton fibres provided the best results.     

The use of carbon nanotubes in textile printing

The characteristic properties of carbon nanotubes (CNTs), particularly their heat conduction, electrical conductivity, high modulus of elasticity, high strength, and resistance to chemicals, have resulted in widespread application of CNTs in nanotechnologies. In this study, CNTs were used to impart specific functionality to textiles by printing techniques. To this aim, modified commercial aqueous dispersions of multiwalled CNTs from Nanocyl^® were used for preparing special compositions as paste for printing by conventional techniques (screen printing) and as inks for ink‐jet printing to bestow the fabric antistatic and antibacterial properties. Taking into account the importance of the dispersion level of CNT in the printing composition from the point of view of antistatic properties, the quality of the CNT dispersion was assessed on the basis of particle size distribution by means of a DLS PSS Nicomp device. Printings were done on two types of woven fabrics: 100% cotton and 30/70% cotton/polyester blend. The CNTs used in printing were found to impart antistatic and antibacterial properties to the printed fabrics. These imparted properties were resistant to repeated washing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface-modified and micro-encapsulated pigmented inks for ink jet printing on textile fabrics

Surface-modified and micro-encapsulated pigment dispersions were formulated into pigmented ink jet inks and their properties were analyzed. The changes in viscosity, and particle size distribution, and ink stability were observed every week for 12 weeks at ambient temperature. All the ink jet ink properties were in the operational range. As for appearance and color, the surface-modified pigmented inks printed on a silk fabric yielded higher optical densities, better tone reproduction, wider color gamut, and a larger gamut volume than the micro-encapsulated pigmented inks. For permanence and usability, the micro-encapsulated pigmented inks gave better fastness; the wear comfort of the printed silk fabric, evaluated by the bending stiffness, indicated a negative effect on the pre-treatment of the fabric. Surface pre-treatment of the textile fabrics affected color, appearance, permanence and usability. Despite almost equal numbers of threads, the fabric bending strength in the weft direction was much stronger than that in the warp direction.     

Synthesis of waterborne polyurethane ink binder with high T-peel strength and its application in biaxially oriented polypropylene film printing

In order to improve adhesion properties of waterborne polyurethane (WPU) inks on biaxially oriented polypropylene (BOPP) films, herein, a liquid polyester polyol BY3003 with long-branched aliphatic chains was used to prepare WPU latexes suitable for BOPP films printing. The application of BY3003 made the surface tension of the prepared latexes not more than 43 mN/m, while that of traditional WPU latex exceeded 55 mN/m. Accordingly, the T-peel strength of the inks made from these latexes was all above 0.8 N/15 mm. In addition, post chain extension degree, dimethylol butyric acid content, and NCO/OH molar ratio also had significantly effect on latex and film properties of WPU, especially on the T-peel strength of the corresponding inks. By optimizing these factors, a WPU latex with surface tension as low as 39.6 mN/m and adhesion fastness over 95% on BOPP film were obtained, and the T-peel strength of its corresponding ink was up to 2.05 N/15 mm, which is the highest value recorded in the literature as far as we know.     

Ink‐jet printing of nylon fabric using reactive dyestuff

This study discusses ink‐jet printing of nylon fabric with reactive dyestuff. Specifically, this paper investigates the impact of the concentration levels of pretreatment paste on fabric permeability, and examines the influence of various acid agents, hygroscopic agents and different processing conditions on colour yield. Results show that ink‐jet printing displayed excellent wet fastness in repeated wash testing. This study used four reactive dyestuffs, cyan, magenta, yellow and black, all of which achieved both wash fastness and crock fastness of grade 4.     

Photochromic ink formulation for digital inkjet printing and colour measurement of printed polyester fabrics

The application of a series of commercial photochromic dyes to polyester fabric by a digital inkjet printing method was investigated. Solvent‐based ink systems using the dyes were formulated. The inks were characterised in terms of their physical properties which are related to the jettability of the inks, and finally the prints were fixed onto polyester fabrics by thermal fixation. Colour measurement of the printed fabrics was used to measure their degree of photocoloration, fading rate, fatigue resistance, and storage stabilities. The measured properties of the inkjet‐printed fabrics were compared with the same properties of the same dyes applied to polyester fabrics by dyeing methods. The printed fabrics demonstrated inferior performance in terms of the degree of photocoloration, superior performance in the case of background colours, a higher rate of fading, and a lower fatigue resistance compared with that shown by the same dyes applied to polyester fabric by dyeing methods.     

Pretreatment effects on pigment‐based textile inkjet printing – colour gamut and crockfastness properties

The application of two commercial pretreatment agents, formulated to improve the performance of a six‐colour nano‐scale pigment ink set during the textile inkjet printing of cotton and polyester (PET) fabrics, was examined. An industrial scale printer, operating at 55 linear m/h and equipped with Kyocera printheads, was used to print on commercial fabrics (180 cm wide) prepared for digital printing. The work employed an industrial scale rather than a benchtop printer to enhance the utility of the results for a commercial environment. The colorimetric attributes of printed fabrics were recorded for the individual inks as well as for spot colour combinations generated using Dr. Wirth RIPMaster v11 software. Colour table profiles were also generated and the colorimetric values of inks were compared. Colour gamuts of inks on cotton and PET, including three‐dimensional volumes in the CIELab space, were examined to assess the role of pretreatment on the colorimetric properties of the printed substrates. It was found that the pretreatments enhanced the ink receptiveness, colour intensity and colour gamut of fabrics. Pretreatment of cotton resulted in a larger gamut and more vivid colours than on PET. However, wet and dry crockfastness results were found to be low. In this regard, Time‐of‐Flight Secondary Ion Mass Spectrometry analysis of fabrics printed in the presence and absence of pretreatment indicated that the low crockfastness arises from higher pigment levels on the surface of the pretreated fabric.