Improving the Dye Coverage of Immature Cotton Fibres by Treatment with Chitosan

A study has been made of the sorption by cotton of chitosan (a partially deacetylated poly(N-acetyl-D-glucosamine)) which had been applied to fabric by pad and exhaust methods. Chitosan pretreatment increases the exhaustion of direct dyes and is also very effective in eliminating differences in colour between dyed immature and mature cotton fibres. Some reduction in dye fastness results from the chitosan pretreatment when the dyeings are aftertreated with a conventional cationic fixing agent. However, much higher levels of fastness are obtained by aftertreatment with fibre-reactive quaternary ammonium compounds; in general, these compounds produce dyeings of similar fastness properties on both untreated and chitosan-treated cotton.     

Application of a hydrolyzable cationic agent,poly(acryloxyethyl trimethylammonium chloride), in salt‐free reactive dyeing for good dyeing properties

Poly(acryloxyethyl trimethylammonium chloride) (PAOTAC), in which cationic groups were connected with the polymer skeleton through ester bonds, was applied in the salt‐free reactive dyeing of cotton with the aim of achieving good dyeing properties. Exhaust and exhaust–pad–steam dyeing procedures were used with the cotton cationized with PAOTAC in the absence of salt; for comparison, both dyeing procedures were also applied with the untreated cotton in the presence of salt. The dyeing results show that only the exhaust–pad–steam dyeing procedure was suitable for dyeing cationic cotton to achieve a high dye fixation. Color yields, colorimetric properties, fastness properties, dyeing levelness, and penetration behaviors with different dyeing methods were evaluated. Compared with the dyeings with untreated cotton in conventional exhaust dyeing, dyeings with cationic cotton in the exhaust–pad–steam procedure showed equivalent or even better fastness with generally higher color yields and good dye penetration. Possible reasons for the improved salt‐free dyeing properties were proposed, and the hydrolysis of ester bonds within PAOTAC under the dyeing conditions was proven by IR spectroscopy. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

New cationic agents for improving the dyeability of cellulose fibres. Part 2-pretreating cotton with polyepichlorohydrin-amine polymers for improving dyeability with reactive dyes

Pretreatment of cotton with polyepichlorohydrin-dimethylamine produces a modified cotton that can be dyed under neutral conditions with selected low-reactivity dyes using a small amount of salt or with selected high-reactivity dyes without salt. The dyeings of treated cotton exhibit improved colour yield and high wash fastness. The properties and the quality of the reactive dyeings are discussed.     

Use of ultrasonic energy in reactive dyeing of cellulosic fabrics

The use of ultrasonic energy in dyeing cotton fabrics with monochlorotriazine and vinylsulphone reactive dyes has been studied spectrophotometrically. The dyeings carried out conventionally and by the use of ultrasonic techniques were compared in terms of percentage exhaustion, total amount of dye transferred to the washing bath after dyeing, fastness properties and colour values of the dyed materials. Overall results have shown that the use of ultrasound in reactive dyeing of cellulosic fabrics can result in energy savings, less water consumption, increased depth of colour and better process conditions.     

The effect of polyhydroxyurethane on dyeing of cellulosic fabrics with direct and reactive dyes

Dye yields and fastness properties are reported for direct and reactive dyes using a modified dyeing solution with polyhydroxyurethane. Excellent dye yields and colour fastness properties were obtained without the use of electrolytes, multiple rinsing or fixation agents, which are normally employed in cotton dyeing. From the results, it was found that polyhydroxyurethane media exhibit better dyeability and fastness than the normal aqueous media. Dye adsorption in polyhydroxyurethane media was much higher than in other aqueous systems. The dyed samples showed good hot pressing and washing colour fastness properties within the color change range. The excellent solubility of these dyes in the polyhydroxyurethane aqueous solution makes them ideal for use in exhaustion dyeing.     

Modification of cotton to improve its dyeability. Part 1 — pretreating cotton with reactive polyamide-epichlorohydrin resin

Pretreatment of cotton with the polyamide-epichlorohydrin resin Hercosett 125 produces a fibre that may be dyed with selected reactive dyes under neutral pH conditions in the absence of salt and with high fixation efficiency. The physical and mechanical properties of the modified cotton, the colour fastness of the reactive dyeings and mechanistic implications are also discussed.     

Microwave‐assisted dyeing of poly(butylene terephthalate) fabrics with disperse dyes

In this study, conventional heating and microwave dielectric heating in the exhaust dyeing of poly(butylene terephtalate) fabrics with disperse dyes were studied in order to determine whether microwave heating could be used to increase the dyeability of poly(butylene terephtalate) fibre in shorter processing times and enable dyeings of adequate wet fastness to be obtained. Accordingly, the samples of 100% poly(butylene terephtalate) single jersey knitted fabric were dyed with CI Disperse Yellow 160 and CI Disperse Yellow 42, CI Disperse Red 177 and CI Disperse Red 91, CI Disperse Blue 79:1 and CI Disperse Blue 54 at 98 °C with or without microwave dielectric heating. The colouristic properties, colour fastnesses and the tensile properties of the dyed fabrics were investigated and compared with each other. Microwave dielectric heating is regarded as a tool for ‘green chemistry’ and provides many advantages over conventional heating without any deterioration in the properties of the dyed materials. Microwave heat dyeing enhances the exhaustion and the fixation of dye, and good colour fastnesses and repeatability in dyeings are achieved in short heating times of the dyebath.     

Effects of atmospheric plasma treatment on the dyeability of cotton fabrics by acid dyes

Cotton fabrics were treated with air and argon atmospheric plasma for surface activation. Activated surfaces were grafted with two different amine compounds: ethylenediamine and triethylenetetramine. Pretreated cotton was dyed with acid dye and the effects of pretreatment on the colour strength, as well as the washing, rubbing and the light fastness of the dyeings, were investigated. Colour yield results showed that grafted ethylenediamine and triethylenetetramine enhance the dyeability of cotton fabric with acid dyes. Fourier transform infrared spectra confirmed the formed groups on the surface and scanning electron microscopy showed the etching effect of plasma.     

Continuous dyeing of cationised cotton with reactive dyes

Cotton fabrics pretreated with cationic starch have been dyed with reactive dyes by a continuous dyeing method and the pretreatment conditions influencing dyeability of the treated cotton investigated. Cationised cotton has been found to give level dyeing without the presence of salt and dye fixation is improved compared with untreated cotton. The dyeings show good wash and rub fastness.     

Evaluation of colour fastness and thermal migration in softened polylactic acid fabrics dyed with disperse dyes of differing hydrophobicity

This paper addresses the relative effects of softeners having different properties and their method of application (exhaust vs pad) on the colour fastness of poly(lactic acid) fabrics dyed with a range of disperse dyes with different levels of hydrophobicity. A comparison was made with a correspondingly finished polyethylene terephthalate fabric. Possible relationships between the levels of hydrophilicity/hydrophobicity of the dye, and softener, and the colour fastness were explored. Finally, the amount of dye thermally migrated into the finish on the softened poly(lactic acid) and polyethylene terephthalate fabrics was examined in comparison with their colour fastness. Softened poly(lactic acid) fabrics dyed with CI Disperse Red 167.1 exhibited more thermal migration, and hence lower colour fastness, than the corresponding polyethylene terephthalate fabrics. Conversely, softened poly(lactic acid) fabrics dyed with Dianix Deep Red SF exhibited less thermal migration, and hence better colour fastness, than the corresponding polyethylene terephthalate fabrics. Overall, no clear relationship was found between the hydrophobic nature of the disperse dye and the hydrophobic character of the softener on the colour fastness.     

Deep‐coloured polyester/cotton blends with low concentrations of polymethylol dyes by a one‐pass continuous dyeing process

An obvious limitation of the one‐pass continuous dyeing process for polyester/cotton blends is its inability to achieve deep colour depth, which is caused by the low dye fixation yields of commercial reactive dyes. In this study, the performances of polyester/cotton blends dyed with high‐fixation polymethylol dyes and disperse dyes were compared with those of polyester/cotton blends dyed with a mixture of reactive dyes and disperse dyes. Polymethylol dyes were observed to be suitable for dyeing polyester/cotton blends when used in low concentrations; the required concentrations of polymethylol dyes were only 23–58% of the concentrations of commercial reactive dyes required to reach a given colour level on polyester/cotton blends. The wash and crocking fastness of polyester/cotton blends dyed with polymethylol dyes were similar to those of polyester/cotton blends dyed with reactive dyes.     

The use of nutshell firstly as a natural dye for cotton and wool and then as a natural adsorbent for colour removal of basic dye effluent

The aim of this study is to utilise nutshell, which is normally a waste. To this end, in the first part of our study we investigated the usability of nutshell extract solution as a natural dye for the coloration of cotton and wool fabrics. In order to optimise the fastness properties of dyed samples, mordant type was chosen as a variable in experiments and dyeings were carried out at 100 g l⁻¹ extract concentration. After extracting its dye, nutshell was used as adsorbent for colour removal of basic dye effluent. The effect of adsorbent dose, initial dye concentration, and contact time on the adsorption of malachite green (MG) onto nutshell was investigated. Adsorption isotherms and kinetics of MG adsorption onto nutshell were also studied.     

Investigation into the effect of a plant‐derived stabiliser on the light and wash fastness of sulphur‐dyed cotton and nylon fabrics

In this study, cotton fabric and nylon fabric were dyed with a range of commercial sulphur dyes and the light and wash fastness of the coloured fabrics was investigated. The effect of after‐treating the coloured cotton and nylon fabrics with a tannin‐based commercial product, Bayprotect Cl, in the presence or absence of sodium sulphate in the treatment bath, was found to significantly improve the light fastness of the sulphur‐dyed cotton, and the photoprotective effect was partially stable to ISO 105‐C06 washing. In addition, the tannin‐based after‐treatment also improved the colour stability of the dyed fabrics to the perborate‐based ISO 105‐C06 washing. The possible mechanisms for the improved fastness properties are also discussed. The application of sulphur dyes to nylon is potentially commercially useful but has been limited because of the reported poor light fastness of the dyeings. The photoprotective effect of the tannin‐based after‐treatment was investigated with a view to providing the necessary commercial performance. However, it was established that on this fibre, the light fastness improvement was marginal, and the associated wash fastness to oxidative bleach‐based ISO 105‐C06 washing was limited.     

Novel hydrolysable azo disperse dyes based on N‐ester‐1,8‐naphthalimide: dyeing of polyester–cotton blends

The dyeing of polyester–cotton blends with new alkali‐hydrolysable azo disperse dyes based on N‐ester‐1,8‐naphthalimide was investigated. Polyester–cotton blend fabrics were dyed using both one‐ and two‐bath methods. Dyes 3 and 4 offered lower colour yield on polyester using the one‐bath method. For the rest of the dyes, employing either the one‐ or two‐bath method resulted in a similar colour yield on polyester fabric. The results for fastness properties and colour yield of the dyeings showed that the dyes were suitable for dyeing polyester–cotton blends using the one‐bath method. The kinetic study of hydrolysis of the dyes in alkali media obeyed the pseudo first‐order reaction rate.     

Colour and fastness of natural dyes: revival of traditional dyeing techniques

Cotton and wool fabrics were dyed with nine natural dyes obtained by aqueous extraction of the original plants/insect in an attempt to reconstruct traditional textile dyeing recipes, to optimise the methodology at all stages, i.e. extraction, mordanting and dyeing, and to standardise it. Cochineal, madder, alkanna, henna, brazilwood, red sandalwood, safflower, indigo and logwood were used for the dyeings, which were carried out directly and after mordanting of the textile material. A variety of mordants, namely, aluminium potassium sulphate, potassium dichromate, copper sulphate, zinc chloride, iron(iii ) chloride, iron(ii ) sulphate and tin chloride, is anticipated to meet both early and recent requirements and options. The dyeings were evaluated through colour measurements and standard wash, light and rub fastness tests. Generally, the mordanting process known for many centuries and connected with the textile dyeing resulted in an improvement in dye absorption and fastness properties mainly for the cotton samples, as is concluded from the tests and measurement assessments.     

Electrostatic self‐assembly dyeing of cotton fabrics

A new approach to the dyeing of cotton fabrics using an electrostatic self‐assembly method was evaluated. Cotton fabrics were pretreated with 2,3‐epoxypropyltrimethylammonuium chloride and cationic charges were produced on the fabric surfaces. For the dyeing of cotton fabric, reactive and acid dyes were used. Oppositely charged anionic reactive/acid dyes and cationic poly(diallyldimethylammonium chloride) were alternately deposited on the surface of cationised cotton fabrics. Ten multilayer films of dye/poly(diallyldimethylammonium chloride) were deposited on the cotton fabric surfaces using a padder. The build‐up of the multilayer films and the level of colour strength (K/S) achieved are discussed. Samples of cotton fabrics were also dyed with the same dyes, but using the exhaust method, and both types of dyed samples were compared. The washing, rubbing and light fastness properties were evaluated for the dyed fabrics.     

Investigation into the sequential application of cationic/anionic fixing agents to improve the oxidative washing resistance of CI Leuco Sulphur Black 1‐dyed cotton fabric

Sulphur‐dyed cellulosic textiles are susceptible to washing powders containing activated peracid formulations resulting in obvious fading during repeated laundering. This study presents a novel one‐bath/two‐stage exhaust finishing process to improve the oxidative wash fastness of CI Leuco Sulphur Black 1‐dyed cotton fabric. The effect of the combined Tinofix ECO and Bayprotect Cl after‐treatment was to impart better colour fastness to oxidative International Organisation for Standardisation (ISO) 105 CO9 washing of the dyed cotton compared with those dyed fabrics after‐treated with Tinofix ECO alone. In addition, while the dyed fabrics rub and light fastness performances were unchanged by the after‐treatments, some improvement in the tensile strength of the combined Tinofix ECO and Bayprotect Cl after‐treated fabrics was observed.     

A new approach for dyeability of cotton fabrics by different plasma polymerisation methods

The increased dyeability of cotton fabrics in low temperature media using two different plasma polymerisation methods was investigated in this study. In the first method, fabrics were directly treated in amine plasma (ethylenediamine or triethylenetetramine). In the second method, they were first treated in argon plasma and then immersed in an aqueous amine bath. The treated fabrics were then dyed with a reactive dye (Remazol Black B) and the colour yields and fastness properties of the resulting fabrics measured. The K/S values obtained were significantly improved when compared to the untreated fabric.     

Dyeing of polyester and its blends with some disazo dyes derived from the disodium salt of chromotropic acid and their chelates with transition metal ions

Disazo dyes derived from the disodium salt of chromotropic acid and their chelates with metal ions were applied on polyester, polyester/cotton and polyester/wool blend fibres as disperse dyes. The fastness to washing, perspiration, rubbing and light of the resultant dyeings were measured. The bonding of dye or its complexes to the fibre and the effect of substituent groups on the colour fastness of the dyes are discussed.     

A method for dyeing cotton fabric with anthocyanin dyes extracted from mulberry (Morus rubra) fruits

For the first time, the natural anthocyanin dyes (mainly consisting of cyanidine 3‐glycoside) extracted from mulberry (Morus rubra) fruits has been successfully used to dye cotton fabric, with a dyeing property performance good enough for potential commercial applications. In this study, succinic acid was firstly incorporated into cotton fabrics by esterification to the hydroxyl groups of cellulose, forming an anionic site for the dyes. The performance of the modified material was characterised by Fourier transform infrared spectroscopy and tensile strength. Results showed that the tensile strength of cotton fabrics was mostly retained after modification. The anthocyanin extracts from mulberry fruits were used to study the dyeability of the control and modified cotton fabrics. Red and deep purple (aubergine) are two main shades of cotton fabrics dyed with mulberry fruit extracts. Most importantly, aubergine shade is rare in cotton fabrics dyed with natural dyes. Modification with succinic acid clearly increased the colour strength of the dyed cotton fabric. The colour strength of dyed cotton fabric was improved from 2.7 to 5.3 in the case of dyeing without mordants, and from 3.2 to 6.9 in the case of dyeing with tin mordanting. Meanwhile, the colour fastness was improved by 0.5–2 grades with increasing succinic acid concentration in the finish solution. The colour fastness to perspiration, crocking, light, and washing of fabric dyed with simultaneous tin mordanting and modified with 30 g l^?1 of succinic acid was found to be acceptable, with a grey scale grade of at least 3. As for home laundering, neutral soapy solution was more acceptable than alkaline soapy solution.