Enhancing the outline sharpness of crosslinked printed cotton fabrics using ethylene glycol diglycidyl ether

In the current study, to obtain environmentally friendly printed cotton fabrics with a clear contour edge, ethylene glycol diglycidyl ether (EGDE) as a crosslinking agent and guar gum as a thickener were used with natural madder dye. The solid content of the thickener was assessed to determine the optimal viscosity of the printing paste. Scanning electron microscopy images and colour depth (K/S) values were used to analyse the surface morphology and printing properties. The pattern outline of the printed cotton fabric was assessed with an optical microscope. Also, the overall fastness properties of the printed fabrics were evaluated. The results showed that when the solid content of guar gum was 2.5%, the viscosity of the printing paste was close to 10 000 mPa.s, which was suitable for printing cotton fabrics. Scanning electron microscopy analysis showed that most of the printing paste was removed during the washing process, and did not affect the microstructure of the cotton fabric. Compared with direct printed cotton fabrics, the K/S values of mordant and crosslinked printed cotton fabrics increased by 3.12 and 4.01, respectively. In the optical microscopy photographs, the mordant and crosslinked printed cotton fabrics displayed a clear outline sharpness of the printed pattern, and excellent printed products were obtained. The colour fastness to washing, rubbing and light of the crosslinked printed cotton fabric were significantly improved, reaching levels of 4-5.     

Modified guar gum: An alternative source for printing of cotton fabric with reactive dye

The alginate thickener is the thickener frequently used for reactive printing of textile. The thickener responds with reactive pigments and thus does not lead to the fabric composition becoming stiffer. In this study, we prepared oxidised natural guar gum with hydrogen peroxide, sodium hypochlorite and sodium hydroxide. All other polysaccharides comprise reactive hydroxyl units with a stronger reactivity that must be replaced if they are to be used in reactive printing. Guar derivatives were synthesised and verified using Fourier-transform infrared (FTIR) spectroscopy. Natural thickeners, synthetic guar gum derivatives, have been employed in textile printing technique. In comparison to other synthetic thickeners, modified environmental guar gum polymer has been shown to be an ecologically friendly and low-cost thickener. Cotton fabric printed with modified guar thickening with hydrogen peroxide has even stronger colour strength than fabric printed with sodium alginate thickener, which is highly favourable. Penetration properties, colour value, colour strength, colour fastness to washing, light and rubbing was compared with alginate thickener (readily available on the market). Guar gum thickeners showed enhanced features versus sodium alginate for reactive printing. Partially replaced guar gum is an appropriate option due to the colour and physical properties.     

Enzymatic improvement of guar‐based thickener for better‐quality silk screen printing

Guar galactomannan (referred to as guar gum) is a versatile polysaccharide, obtained from the seeds of the shrub Cyamopsis tetragonolobus, which finds several applications in either its native or chemically modified form. For textile printing, guar gum can also be partially depolymerised in order to promote dye penetration, improve swelling in water and achieve the desired rheological properties. Guar gum is obtained from guar seeds by a thermo‐mechanical process that leaves ca. 3% of largely insoluble proteins in the gum, originating from the endosperms aleurone layer. When printing silk fabrics with acid or premetallised dyes, guar endogenous insoluble proteins bind tightly to anionic dyes, causing deposition of coloured aggregates on the fabric. This causes imperfections on the printed fabric in the form of tiny, but visible, ‘dots’, which lowers the quality of the final articles. In order to eliminate ‘dotting’, a novel printing thickener composed of depolymerised guar gum mixed with a bioengineered subtilisin protease has been developed. Upon solubilisation of the gum, and during preparation of the printing paste mixture, the protease hydrolyses guar gum insoluble proteins, generating soluble peptides that are washed off by the post‐printing treatments of the fabric. This enzymatic application prevents ‘dotting’ and significantly improves the quality of the silk print, without any measurable tensile strength loss of the fabric.     

Influence of bifunctionality of reactive dyes on the bending rigidity of viscose printed with polysaccharide thickeners

The bending rigidity and colour depth of viscose printed with a number of reactive dyes in the presence of alginate and guar gum thickeners has been investigated. Interactions between the fabric, the dyes and the thickener were evaluated to determine the bending rigidity of the printed substrate. The results show that mono- or bi-functional reactive dyes cause undesired stiff fabric handle depending on the structure (the type of the reactive system and the reactive group), the reactivity and the concentration of the reactive dye used. These interactions differ to a greater degree when guar gum thickeners are used.     

The Influence of Different Substitution Levels of Guar on the Quality of Viscose Prints with VS Monoreactive Dye

Abstract

The basic problem of reactive printing on viscose with polysaccharide guar thickeners is the capability of dye molecule to react with the hydroxyl groups of cellulose (binding of the dye) as well as with the hydroxyl groups of water (the dye hydrolyzes) or the thickener (binding of the dye) (1, 2]. This latter is most clearly expressed in combination of the polysaccharide unmodified guar thickener and the bifunctional reactive dye where the bifunctional dye forms, due to the presence of two reactive groups, a bridge between the cellulose fibre and the guar thickener (3). The unmodified guar has a large number of free hydroxyl groups which cause crosslinking with cellulose and hinder the thickener to wash off, thus increasing the stiffness of the printing fabric. The further investigation has shown that this undesireous reaction with the guar molecules can be partly diminished by the suitable selection of chemically modified guar thickener or by lowering the dry substance content [4, 5].

In this paper the influence of nonsubstituted and different substitutited guar thickeners with monoreactive (vinylsulphone) dyes on the changing of fabric stiffness will be shown.     

Dry transfer printing of silk and cotton with reactive dyes and mixed polysaccharide thickeners

Dry transfer technology involving adhesion and steaming was designed for the printing of untreated silk and cotton with reactive dyes. The transfer paper was prepared by coating mixed polysaccharide thickeners composed of adhesive high‐substituted hydroxypropyl cellulose (H‐HPC) and another thickener, either sodium alginate (SA), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), guar gum (SG‐9) or carboxymethyl starch (SG‐24). Patterns on the transfer paper were obtained by means of ink‐jet. The thermal plasticity of H‐HPC was observed and 120 °C was determined as the adhesion temperature. Rheological testing of all the thickeners verified that their shear‐thinning behaviour favoured successful coating. By comparing the effects of different mixed thickeners on the prints’ quality with regard to colour depth, sharpness, colour fastness and handle, it was concluded that the colour depth depended on the adhesion extent and reactivity between the thickener and reactive dye. Using H‐HPC/SA and H‐HPC/HEC produced the highest and lowest colour depths, respectively. The sharpness was visibly influenced by the different mixed thickeners. A clear pattern was achieved when the other thickener was CMC, SG‐9 or SG‐24. Both the colour fastness and handle were desirable, irrespective of the mixed thickeners used.     

Effective textile printing using different enzyme systems

The possibility of using enzymes in natural and synthetic thickener systems for the printing of cotton and wool has been investigated, in particular the effect on colour and surface structure. The efficiency of different enzymes (cellulases, proteases and laccases) concerning their applicability, i.e. activity and stability within different thickener systems (polysaccharide, acrylic polymer and their mixtures), was studied. Rheological parameters (viscosity and viscoelasticity) of the printing paste were determined and the colour and/or structure effects on the fabric surfaces were assessed. The rheological investigations showed that degradation of the structure of the thickener system could occur in the case of an inappropriate combination of thickener and enzyme product leading to pseudoplasticity and decreased elasticity of the paste.     

Polymerization of fluoroacrylate and guar gum copolymer as a new pretreatment paste for ink‐jet printing of polyester

A novel pretreatment paste containing fluoroacrylate copolymer and modified Guar Gum was carried out on the polyester fabric to provide partial water repellency and printability after inkjet printed with water‐based disperse dye inks. The stable fluorinated pastes were prepared via miniemulsion polymerization of fluoroalkyl acrylates, styrene, 2‐ethylhexyl acrylate, and modified guar gum in the presence of AIBN as initiator, CTAB and polyoxyethylene polyaryl ether as surfactants under suitable reaction conditions. In the analysis of monomer conversion and particle size, the highest polymerization rate with smallest particle size was obtained with increasing concentration of surfactants and initiator but the decreasing degree of substitution of guar gum to imply stronger interactions between fluoroacrylate monomers, hydroxyl groups of modified guar gum and EO units of nonionic surfactants. The 30% of stock fluorinated paste with urea concentration of 6% provided the prints with highest K/S value, satisfactory edge acuity and least color difference between front and back sides of the fabric to show more transparency. The rating 80 of water repellency tested on the best treated polyester fabric demonstrated stain proof properties after sprayed with water and dried. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The application of chitosan in pigment printing

The use of chitosan as a combined thickener and binder in pigment printing has been examined in comparison with a commercial printing system (Alcoprint). Printing pastes made up from mixtures of chitosan, pigment and acetic acid at the appropriate viscosity gave satisfactory prints on polyester and 67:33 polyester/cotton woven fabrics. Rheological data showed the chitosan pigment paste had a much lower yield point than commercial printing paste though no difficulties were found in its use. Curing of the chitosan print at 150°C for 6 min gave samples of comparable colour fastness to the commercial printed samples when subjected to the rubbing and washing tests. The only drawbacks noted in using chitosan in this way were a reduced colour yield and a much higher fabric stiffness.     

Properties of UV-cured pigment prints on textile fabric

This paper studies and evaluates the UV-curing of pigment prints on textile fabric using a prototype UV scanner. A printing paste comprising synthetic thickener, emulgator, binder, pigment dispersion and photoinitiator was applied using a flat screen printing technique onto the cotton fabric, then dried and exposed to heat or UV-radiation under a mercury vapour lamp (200 W cm⁻²). The characteristics of cured prints such as paste add-on, colour properties, colour fastness to washing and dry/wet rubbing were evaluated, together with fabric stiffness. The effects of UV-curing were evaluated by Attenuated Total Reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The properties of the UV-cured pigment prints were compared with those of the thermal cured prints. Analyses of the obtained results helped to define the optimum composition of the photo reactive pigment paste, and the UV-curing conditions under which satisfactory results were obtained, comparable with those from the thermal curing method.     

Optimisation of process parameters of Alpaca wool printing with Juglans regia natural dye

The aim of this research study was to optimise the process parameters of Alpaca wool hand‐knitted samples screen‐printing with Juglans regia natural dye and to set the optimal conditions regarding colour yield, colour fastness and colouristic properties of printed samples. An extensive preliminary examination of the Alpaca woollen yarn and hand‐knitted samples characteristics, the characteristics of suitable thickeners and the optimisation of the printing paste composition, was performed. A starch‐based thickener, British Gum, with a dry matter content of 4% was selected due to its rheological properties responding to properties of the Alpaca yarn and knitwear. It was determined that the fluidity increases while the viscosity and the elasticity decrease in acidic pH, so a pH of 4 was set for the thickener preparation. The thickener of lower viscosity and higher fluidity assures easier pressing of printing paste through the screen, giving uniform colour yield on the substrate, contributing to easier absorption of dyes into the fibre. A 45‐minute fixing process at 105°C by steaming delivered the best results of printing quality. Iron sulphate was used as the mordanting agent. The colour fastness to washing, dry and wet rubbing, and to light, was tested for samples with and without mordanting. The highest light and washing fastness were obtained with the iron sulphate mordanting agent printed in acid (pH 4) with paste containing 4% dry matter‐based thickener. The rubbing fastness was satisfactory for samples with iron sulphate printed with paste containing 4% dry matter thickener, fixed for 45 minutes, regardless of the pH.     

Cationic pretreatment of cotton fabric for anionic dye and pigment printing with better fastness properties

Improved printability with pigment and anionic dyes was obtained after simple cationisation of cotton fabrics with Solfix E. Different print paste formulations were used for printing cationised cotton fabrics with pigment, acid and direct dyes. Print pastes containing a synthetic thickener or a pigment emulsion showed good suitability for printing with pigment and pastes containing Meypro-gum as a thickener showed good printability with anionic dyes. The prints obtained on cationised cotton showed better overall fastness properties than prints obtained on untreated cotton. After repeated washings, the prints on cationised cotton showed a much smaller percentage colour loss than the prints on untreated cotton fabric.     

Aloe vera gel: a new thickening agent for pigment printing

An attempt was made to print cotton fabric with pigments using a new thickening agent based on Aloe vera gel in combination with sodium alginate. The results were compared with the standard conventional printing recipe containing synthetic thickener, and a favourable effect of Aloe vera introduction was achieved. The results show that the properties of the printed fabric (sharpness, colour yield, overall fastness properties, softness, and water vapour transmission) are dependent on the percentage of Aloe vera gel in the thickener combination, the concentration of printing auxiliaries, and the curing conditions. Optimal printing properties were achieved by using a printing paste containing 80% Aloe vera/20% sodium alginate (700 g kg^?1), pigment (50 g kg^?1), binder (145 g kg^?1), fixer (10 g kg^?1), and ammonium sulfate (5 g kg^?1), followed by drying at 85 °C for 5 min and curing at 150 °C for 3 min. The sample printed with the new recipe showed superior rubbing fastness and handle properties, with a slightly lower colour yield, when compared with the sample printed with synthetic thickener. Finally, economic issues arising from synthetic thickener substitution are highlighted.     

The importance of film thickener structure,dye vapour pressure and solubility parameter in sublimation transfer printing

An attempt has been made to highlight the importance of the structure of the thickener film for dye release in sublimation transfer printing. The roles of (a) dye vapour pressure and (b) the solubility parameters of the dye and of the fibre have also been investigated. Indalca gum was found to hinder the release of dye from paper, resulting in low dye transfer. The incorporation of a suitable auxiliary in the print paste was helpful in eliminating the barrier action of the thickener film. It is suggested that, after the release of dye from the thickener film, the rate of transfer was dependent on dye vapour pressure, while the actual amount of dye transferred was governed by the solubility parameter of the dye and of the polyester fibre.     

Use of a biomaterial as a thickener for textile ink‐jet printing

The feasibility of using chitosan as a thickener in the pretreatment print paste for textile ink‐jet printing was explored. An orthogonal analysis was used to determine the optimum conditions for using chitosan as a thickener in the pretreatment print paste and the effects of different process factors for achieving the best color yield in textile ink‐jet printing. With the help of the orthogonal analysis, the importance of different process factors was found to be in the order of (1) the amount of urea used, (2) the amount of chitosan used, (3) the amount of sodium bicarbonate used, and (4) the steaming time. On the basis of the results of the orthogonal analysis, the optimum conditions for using chitosan as a thickener for the pretreatment print paste were concluded to be 40 mL of chitosan, 10 g of urea, 8 g of sodium bicarbonate, and 5 min of steaming. According to an analysis of the results of different color fastness tests, chitosan could principally work as a pretreatment print paste thickener. However, the final color yield obtained from chitosan‐containing cotton fabrics depended greatly on the stage of the chitosan application. Nevertheless, the color fastness properties and the outline sharpness of the prints of cotton fabric were greatly improved by the chitosan treatment. A two‐bath chitosan treatment was developed to separate the chitosan from sodium bicarbonate and urea before it was padded onto the fabric surface to minimize the neutralization effect. On the basis of the results for the highest color yield obtained on the cotton fabric, it was confirmed that the two‐bath chitosan treatment was successfully developed. In addition, chitosan could impart higher antibacterial properties with a slight reduction in the tensile strength of the cotton fabric. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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.     

Polymerization products of acrylic acid with Gleditsia triacanthos gum as thickeners for reactive printing

Glactomannan gum was isolated from Gleditsia triacanthos seeds. It was then subjected to polymerization with acrylic acid using potassium persulfate initiation system. Products of the polymerization reactions are referred to as composites. Technical evaluation of the latter as thickening agent in reactive printing using cotton fabric was studied. The use of composite in printing cotton fabric with natural dye was also studied. It was found that the composite pastes are characterized by a non‐Newtonian pseudoplastic behavior, and their apparent viscosity increases on increasing the concentration of acrylic acid. The composite can be diluted by water and its viscosity increases by neutralization. Printing pastes of the composite are very stable for storing, in contrast with those of natural gum which exhibit no stability for storing. It was also found that reactive prints thickened with the composite display relatively higher K/S than those thickened with native gum do. Meanwhile, K/S values of prints thickened with the composite are comparable with the values of those thickened with sodium alginate. Printed fabrics using the composite as a thickener exhibit soft handle, and their overall fastness properties are almost equal to, if not higher than, the properties of those printed using sodium alginate. On the other hand, printing of cotton fabric with a natural dye using the composite as a thickener results in prints with K/S values lower than those obtained using commercial synthetic thickener; but the overall fastness properties are nearly the same. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 931–943, 2006     

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.     

Prediction of depth of shade of a dyed polyester fabric based on fibre fineness and fabric structure

A colour prediction model containing four parameters of dye concentration, fibre fineness, fabric roughness and dye parameter is developed. The model can predict the shade depth of a dyed polyester fabric. The relationship among these factors and shade depths of dyed polyester fabrics was investigated to elucidate the role of fibre fineness and fabric structure on surface reflectance and colour efficiency. The shades of several additional dyed samples were measured and compared against the predicated values to validate the accuracy and performance of the model. The results showed that the predicated depths of shade matched the experimental data to a good extent.     

New thickening agents for reactive printing of cellulosic fabrics

Four adducts were prepared by polymerizing acrylic acid (AA) in presence of either a pyrodextrin (D) or gum Arabic (GA), and termed as PAA/D₁, PAA/D_2, PAA/GA_1, and PAA/GA₂. These adducts were utilized as thickeners in reactive printing of cotton fabric in comparison with Na‐Alginate. Printing was carried out at different conditions including: NaHCO₃ concentration (0–40 g/K), urea concentration (0–200 g/k), steaming temperature (100–130°C) and time (5–35 min). At optimal NaHCO₃ concentration (30 g/K) the depth of shade of the prints, expressed as K/S values, depended on the nature of the thickener used, and followed the descending order PAA/D₂ > PAA/GA₁ > Na‐Alginate ?PAA/D₁ ≥ PAA/GA₂. Accordingly, PAA/D₁ and PAA/GA₂ were omitted in subsequent trials. Optimal printing conditions were found to be NaHCO₃ concentration (30 g/K), urea concentration (100 g/k), steaming temperature (110°C), and time (15 min). The apparent viscosity of a printing paste, as well as both of K/S value and fastness properties of a print were governed by the nature of the reactive dye and type of thickener. Storing of a printing paste up to 7 days resulted in a decrease in its apparent viscosity along with a slight reduction in K/S value and a little variation in some fastness properties of prints. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4430–4439, 2006