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.     

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.     

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.     

Synthesis,stability and printing properties of a novel 2‐sulphophenoxy‐4‐chloro‐s‐triazine reactive dye for ink‐jet printing of wool

We report here the synthesis and characterisation of a new medium‐reactivity reactive dye containing 2‐sulphophenoxy‐4‐chloro‐s‐triazine, having enhanced the activity of the chlorine atom for further substitution by the functional groups carried by wool fibre. In addition, a dichloro‐s‐triazine dye was also synthesised for the purpose of comparison. The progress of synthesis reactions and purity of the dyes were determined using capillary electrophoresis and thin layer chromatography. The molecular structure and the chemical compositions of the synthesised dyes were confirmed using Fourier Transform–infrared spectral data and elemental analyses. The inks containing the synthesised dyes were formulated and ink‐jet‐printed onto wool fabrics and then the printed fabrics were steamed at 102°C. Compared with the dichloro‐s‐triazine dye, superior performance in terms of ink stability, K/S and dye fixation was observed for the new 2‐sulphophenoxy‐4‐chloro‐s‐triazine dye. In addition, the light fastness of the fabric printed with the inks containing the new dye was 0.5‐grade greater than that of the fabric printed with the inks containing the dichloro‐s‐triazine dye, and no changes in shade and staining were observed following wash fastness tests of the fabrics printed with the inks containing the new dye.     

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.     

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.     

Modified 2,4‐difluoro‐5‐chloro‐pyrimidine dyes and their application in ink‐jet printing on wool fabrics

This paper describes the modification of three commercially available 2,4‐difluoro‐5‐chloropyrimidine dyes (Drimarene Brilliant Red K‐4BL, Drimarene Brilliant Blue K‐BL and Drimarene Golden Yellow K‐2R) by the reaction of the parent dye with 4‐hydroxybenzensulphonic acid sodium salt. Capillary electrophoresis was used to monitor both the course of the above reaction and to ascertain the dye stability of the dyes in an ink formulation. Inks prepared from the modified dyes showed much higher storage stability compared with the parent dye‐containing inks; this was confirmed by capillary electrophoresis analysis. Inks containing the modified dyes were printed on wool fabrics and diffusion/fixation achieved by ‘batching’ the prints at 25 °C; high fixation values were obtained for all three modified dyes. These prints exhibited excellent colour fastness to washing, rubbing and light, the former test confirming a high degree of dye–fibre covalent bonding.     

Ink‐jet printing process for lyocell and cotton fibres. Part 2: The relationship of colour strength and dye fixation to ink penetration

The colour appearance on ink‐jet printed textiles is influenced by a range of factors, including the chemical and physical nature of the fibre, dye–fibre affinity, pretreatment and fabric structure. Regression analyses were conducted to study the correlation between colour strength, fixation and ink penetration obtained by ink‐jet printing lyocell fibres (standard Tencel and Tencel A100) and cotton with an ink based on a monofunctional reactive red dye. The fixation was highest on Tencel A100, followed by standard Tencel and then cotton, while colour strength was highest on standard Tencel followed by cotton and Tencel A100. A linear relationship between colour strength and ink penetration was found with cotton, indicating greater dependence of depth of shade on ink penetration than on standard Tencel and Tencel A100 fabrics, where the interrelationships were more complex, but of low statistical significance. A schematic representation is proposed illustrating the mechanism of ink penetration into pretreated fibres, which provides a reasonable interpretation of the events occurring as dye penetrates into and fixes onto the fibres.     

Digital alkali resist prints on polyester

In earlier papers we have described sulphite‐based and secondary amine‐based resist printing of cotton using ink‐jet procedures. This paper describes the chemical resist printing of polyester fabrics padded with disperse dyes to create a white image on a coloured background. Polyester grounds have been prepared by the pad‐dry ‘dyeing’ of polyester fabrics with alkali‐clearable disperse dyes, such as a Dianix PC (DyStar) or a Dianix SF (DyStar) dye, and subsequently ink‐jet printed with sodium carbonate based ink formulations to yield a white image on a solid ground following high temperature steaming and appropriate wash‐off procedures. Coloured images have been achieved by a two‐step process whereby the coloured ground fabric was initially printed with an alkali‐based ink and then overprinted in a second step with an illuminating ink formulation containing an alkali stable disperse dye, such as a Dianix AD (DyStar) or Serilene ADS (Yorkshire Chemicals).     

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.     

Colloidal properties of copolymer‐encapsulated and surface‐modified pigment dispersion and its application in inkjet printing inks

A styrene–maleic acid copolymer (PSMA)‐encapsulated 2‐[(2‐methoxy‐4‐nitrophenyl) azo]‐N‐(2‐methoxyphenyl)‐3‐oxobutyramide (PY74) dispersion was prepared by the phase‐separation technique. A surface‐modified PY74 dispersion was prepared with PSMA sodium as a dispersant by the milling method. Furthermore, the two dispersions were applied to formulate pigment inks. The colloidal properties of these two dispersions were compared. The printing and color performance of the prepared inks were also investigated. The results show that the PSMA‐encapsulated PY74 dispersion with a small particle size had higher stabilities of NaCl concentration, pH value, and temperature than the surface‐modified PY74 dispersion. The apparent viscosity of the PSMA‐encapsulated PY74 dispersion changed little, while it changed greatly in the surface‐modified PY74 dispersion with an increase of the shear rate from 10 to 100 s⁻¹. The ink printing and color performance of printed Fabrics indicated that the PSMA‐encapsulated PY74 dispersion was more suitable for the preparation of inkjet printing ink than the surface‐modified PY74 dispersion. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of a di‐(p‐sulphophenoxy)‐s‐triazine reactive dye and its application in wool fabric ink‐jet printing

Reactive dyes based on p‐sulphophenoxy‐s‐triazines were synthesised, characterised and applied to wool fabric by ink‐jet printing. The extent of dye‐fibre covalent bonding (% fixation) was measured on prints produced using different development methods. The most promising method to obtain high dye‐fibre fixation values was to interleave the printed wool with a pre‐wetted cotton fabric and store for 3 h. Steam fixation was also investigated but gave lower fixation values. The degree of dye hydrolysis vs time in the ink formulation was evaluated because ink stability is critical in commercial operation; a reformulated ink based on a phosphate buffer was found to improve ink stability.     

Inkjet printing effects of pigment inks on silk fabrics surface‐modified with O2 plasma

Without any preprocessing, silk fabric has lower ability to hold on water due to the smooth morphology of silk fibers. Therefore, patterns directly printed with pigment inks have poor color yields and easily bleed. Plasma surface‐treatment of silk fabric was carried out in an oxygen atmosphere under different experimental conditions. The samples were printed with magenta pigment ink after treatment. The results showed that the optimum treatment conditions we obtained were exposure time of 10 min at a working pressure of 50 Pa and a working power around 80 W. At such conditions, surface‐modified silk fabrics could obtain the effects of features with enhanced color yields and excellent pattern sharpness. Atomic force microscope images indicated that low‐temperature oxygen plasma initiated modifications to the surface of silk fiber with more grooves. Dynamic contact angle analysis showed that the hydrophilicity of silk fiber was remarkably improved after pretreatment with plasma. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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 influence of chitosan and some of its depolymerized grades on natural color printing

Chitosan samples with different molecular weights were prepared using sodium nitrite in acidic medium. These samples were practically confirmed by measuring nitrogen content and average molecular weight. The chitosan samples were applied to cotton fabric by the pad dry method. The pretreated cotton fabric was printed with natural coloring matter, curcumin. The color yield of the prints increased by increasing the molecular weight of chitosan. Both wet and dry rubbing fastness of the prints was good. The stiffness results of the printed cotton fabric pretreated with low molecular weight chitosan showed better performance. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 559–563, 2005     

Synthesis of ZnS–Mn nano-luminescent pigment for ink applications

In the present study, ZnS–Mn nano-luminescent pigments were synthesized, using co-precipitation method. Polyvinylpyrrolidine (PVP) surface modifier and Mn dopant concentrations were considered as affecting parameters. The luminescent ink was loaded with two different concentrations of pigments. The obtained ink was silk-screened on different types of fabrics mainly treated cotton, cotton and nylon. Structure, microstructure, luminescent properties of nano-pigments, inks and fabrics and also rheological properties of the inks were investigated. The results showed that the ceramic ink prepared with nano-luminescent pigment had high photoluminescence (PL) intensity. Moreover, the optimum concentrations of Mn and PVP for obtaining maximum PL intensity were found as 2 and 5 wt%, respectively. SEM images of fabrics indicated that nanoparticles were loaded, nonuniformly, on the fibers. The treated linen and nylon fabrics showed maximum and minimum PL intensity, respectively, due to ink penetration depth in the fabrics. Furthermore, washing fastness estimated for all fabrics was in the proper range.     

Influence of nano‐coated pigment ink formulation on ink‐jet printability and printing accuracy

Pigment ink was formulated with nano‐coated pigment dispersion, prepared via mini‐emulsion polymerization. To study the effect of nano‐coated pigment, surfactant and humectant on ink‐jet printability, the trajectory of droplets with different pigment ink composition was monitored. The effect of ink formulation on the accuracy of printing process of the pigment ink was discussed by study on line width and edge contour of printed patterns. Experimental results indicated that the additives and properties of the pigment ink had a great influence on droplet formation and precise positioning of the printed patterns. The optimal composition for the pigment ink as following: nano‐coated pigment dispersion was 20% w/w, surfactant (S‐465) was 1.5% w/w, humectant (diethylene glycol) was 30% w/w and defoamer (FB‐50) was 0.1% w/w. The prepared pigment ink exhibited excellent freeze–thaw, thermal and centrifugal stability. In addition, the optimal formula was beneficial to form a stable droplet and obtain high precision patterns.     

Disperse ink‐jet inks: properties and application to polyester fibre

Water‐based ink‐jet inks were prepared using press cake samples of two commercially available azo disperse dyes. The suitability of the inks for printing polyester fabric was evaluated via measurement of surface tension, conductivity, viscosity, pH and particle size distribution. Inks prepared by the proposed method fulfill most requirements for an ink‐jet ink depending on the colorant structure, the dispersing agent and the alcohol used. The inks were applied to polyester fabric by both printing and dyeing and the fastness of the ensuing coloured samples was assessed. The fastness properties of the dyed and printed polyester samples were found to be very good to excellent and generally meet accepted customer requirements. Oil‐in‐water microemulsions containing the same colorants were also prepared. Their properties, which are crucial to the suitability for ink‐jet ink, were compared with those of the conventionally prepared inks and were found to be improved, with the exception of conductivity, while surface tension remained within acceptable values.     

Improved chemical resistance of ink‐jet printed micropatterns on glass by using dual‐functional compositions

UV curable and UV/moisture dual‐functional oligomers were synthesized by grafting trimethoxysilane and methacrylate segments on the polyimide oligomer chains. These oligomers and a dual‐functional monomer were used as ink compositions to enhance the chemical resistance of ink‐jet printed LCD color filter micropatterns, without sacrificing jetting performance. The molecular structure and molecular weight of the oligomers were altered to adjust the solubility of oligomer in monomers, together with jetting trajectory, drop size uniformity, and deposition accuracy of the ink‐jet inks. The chemical resistance, optical property, and mechanical property of the printed patterns depend on the oligomer structure, the arrangement of trimethoxysilane groups, and the molecular chain length. Straight lines and uniform dot arrays with excellent chemical resistance can be achieved. Dot patterns made of polymer‐silica hybrid materials and pigments remain unchanged after being immersed in γ‐butyrolactone for 200 min. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2049–2055, 2013     

Use of chitosan to improve dyeability of DP-finished cotton (II)

Chitosan was used to improve the dyeability of DP-finished cotton. Cotton fabric was treated with a mixture of chitosan, 4,5-dihydroxy-1,3-dimethyl-2-imidazolidinone (DHDMI), and catalyst in a one-step process. To investigate the effect of molecular weight of chitosan on the dyeability of treated fabrics, six chitosan samples of different molecular weights were prepared by depolymerization with sodium nitrite; 185,300, 73,200, 59,000, 21,000, 14,000, and 3,800, respectively. Chitosan improves dye uptake of direct and acid dyes considerably, and the dye uptake increases with the increase of the molecular weight of chitosan. Reactive dye uptake increases slightly in alkaline condition as the molecular weight of chitosan decreases. Higher dye uptake is obtained in acidic condition than in alkaline condition. Chitosan treatment has no discernable effect on the colorfastness to washing, but decreases the colorfastness to wet crocking by about half a point. And chitosan affects other properties of treated fabric; lower wrinkle recovery, stiffer handle, and higher breaking strength as the molecular weight of chitosan increases. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1515–1521, 1998