Effect of a cationising agent on the conventional reactive dyeing of cotton

Cationisation of cotton is emerging as an effective tool that may help to solve the environmental problems associated with the dyeing of cotton with reactive dyes. The efficiency of the cationising agent CA200 has been investigated and was found to be more effective when compared with the usual method for reactive dyeing of cotton. Pretreatment of the cotton fabric with the cationising agent increases the rate of dyeing compared with the existing method of reactive dyeing. The colour yields, in terms of the Kubelka–Munk values as a function of the amount of dye fixed, showed that cationisation enhances the colour strength. It also improves the washing fastness, rubbing fastness and depth of shade. The positive environmental impact of this cationisation process is significant and the cationised cotton shows a similar fabric quality as with the normal dyeing process.     

Supercritical fluid dyeing of cotton modified with 2,4,6-trichloro-1,3,5-triazine

Supercritical carbon dioxide dyeing of cotton modified with the fibre reactive group 2,4,6-trichloro-1,3,5-triazine has been examined and the results are discussed. The modification of cotton was carried out in acetone, as well as by a new method using water as the solvent. For level dyeing results a degree of fixation of the fibre reactive group on cotton of 3% owf was required without changing the hydrophilicity of the fibre. The results show that dyeing of modified cotton is possible with dyes containing hydroxy or amino groups which react via a substitution reaction with the chlorine atoms of 4,6-dichloro-1,3,5-triazine-2-yl on the fibre surface. The K/S values at 383 nm of modified cotton dyed with CI Disperse Yellow 23 were found to be between 1.44 and 4.79 depending on the dyeing conditions used. The washing, rubbing and light fastness data that were obtained were between 3 and 5.     

Direct dyes on cotton grafted with 2-vinylpyridine and quaternised with alkyl bromides or epichlorohydrin

The dyeing properties of cotton grafted with 2-vinylpyridine and then quaternised with alkyl bromides or epichlorohydrin were studied under various dyeing conditions, using CI Direct Blue 78 and CI Direct Yellow 106. The results have been compared with those obtained on unmodified cotton.     

Pretreatment of cotton with poly(vinylamine chloride) for salt-free dyeing with reactive dyes

Poly(vinylamine chloride) has been investigated as a pretreatment for the salt-free dyeing of cotton with reactive dyes. Dye fixation was found to be much higher than by conventional dyeing without pretreatment, even in the presence of a large amount of salt. The influence of pretreatment conditions on dye fixation, such as pad–bake variables and the concentration of poly(vinylamine chloride), has been studied. The dyeing behaviour of CI Reactive Red 2 on pretreated cotton was examined and found to follow a Langmuir-type adsorption curve. Dyed cotton pretreated with poly(vinylamine chloride) showed excellent wash fastness and good rub fastness. It is concluded that poly(vinylamine chloride) is effective as a pretreatment for salt-free dyeing with reactive dyes.     

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     

槐米染色棉织物工艺及其抗紫外性能研究

为实现槐米染料的工业化应用及提高棉织物的功能性,分析了使用壳聚糖、Al3+、Fe2+媒染剂预媒染色法对棉织物染色效果的影响,重点研究了铝预媒染方法染色温度、染色时间、pH值等工艺参数对染色棉织物K/S值的影响,并测试了槐米染色棉织物的抗紫外性能。结果表明:直接使用槐米染色的效果较差;壳聚糖媒染对上染效果影响不大,使用铝、铁媒染剂,可得到不同颜色的棉织物;铝媒染剂染色棉织物为鲜艳的黄色,为较好的媒染方法;铝预媒染染色方法染色优化条件为:温度为80℃,染色时间120分钟,染浴pH值为6.8;铝预媒染染色棉织物具有较好的抗紫外性能。     

Prediction of recipes for cotton cationisation and reactive dyeing to shade match conventionally dyed cotton

Cationisation allows cotton to be dyed with anionic dyestuffs (including anionic pigment dispersions) without the need for salt, and with decreased usage of dye, water, and energy. Appropriate cationisation levels play a part in dyeing properties such as fabric levelness, in fastness properties such as lightfastness, and in the overall cost of the cationisation treatment. The objective of this work is to assess whether it is possible simultaneously to predict a dye recipe and cationisation treatment level for cotton to yield a colourless or nearly colourless dyebath at the completion of the dyeing to match the shade of conventional fibre reactive dyeing of cotton. It has been shown that it is possible to model a cold pad batch cationisation process, relate the colour yield data and cationisation level for individual dyes, and finally predict a dyeing recipe and the required corresponding cationisation treatment to match the shade of conventional fibre reactive dyeing of cotton. The predicted dye recipe and cationisation amount yield colourless or nearly colourless dyebaths at the conclusion of the dyeing process.     

Preparation and surface activity of biodegradable polymeric surfactants II: Dyeing properties of biodegradable dextrin derivatives in cotton dyeing

The biodegradability and dyeing properties of a series of dextrin‐derivative surfactants in direct‐dye cotton‐dyeing systems have been studied. It was found that these surfactants have good biodegradability, which is lacking in traditional dyeing auxiliaries. In dye‐surfactant systems, the degree of aggregation of direct dyes with surfactants was found to influence the rate of cotton dyeing. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2620–2624, 2007     

Application of polycarboxylic acid sodium salt in the dyeing of cotton fabric with reactive dyes

In this study, the effects of polycarboxylic acid sodium salt on the dyeing of cotton with reactive dyes were evaluated by measuring and comparing the K/S values and dyeing fastnesses of the dyed cotton fabric samples. Results showed that the K/S value and dyeing fastness of cotton fabrics dyed with polycarboxylic acid sodium salt, substituting inorganic salts as exhausting agent were close to that of with sodium chloride when dip‐dyeing process was used. While, in pad‐dry dyeing, the K/S value of cotton fabric samples dyed with polyacid salts as exhausting agent was higher than that of with sodium sulfate, and the dyeing fastnesses of these samples were nearly the same. The dyeing mechanism of cotton fabric with reactive dye, using polycarboxylic acid sodium salt as exhausting agent was analyzed. The dyeing exhausting mechanism of reactive dye seems different when the inorganic salt and polycarboxylic acid sodium salt were used as exhausting agent in the dyeing of cotton fabric with reactive dye. The polycarboxylic acid sodium salt, as weak electrolyte, increased the dye‐uptake of reactive dye on cotton fabric not only by screening negative charges on cotton surface, but also by the effect of salting‐out or hydrophobic combination. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Influence of different preparation and dyeing processes on the physical strength of the Ingeo† fibre component in an Ingeo fibre/cotton blend. Part 1; Scouring followed by dyeing with disperse and reactive dyes‡

A study has been conducted to examine the effect of different preparation and dyeing processes on the physical strength of the Ingeo fibre component of an Ingeo fibre/cotton blend. An alkaline scouring process (for the cotton), followed by a two‐bath, two‐stage dyeing process in which the Ingeo fibre underwent a simulated dyeing with disperse dyes, followed by the cotton being dyed with reactive dyes, caused minimal deterioration to the strength of the Ingeo fibre. However, it is considered that problems might arise if the Ingeo fibre was subjected to prolonged dyeing times, particularly at neutral or alkaline pH, e.g. if an excessive number of shading additions needed to be carried out.     

Pretreatment of cotton fabrics with polyamino carboxylic acids for salt‐free dyeing of cotton with reactive dyes

In this study, polyamino carboxylic acids have been used to improve the dyeability of cotton in a salt‐free reactive dyeing process. These polyamino carboxylic acids were prepared by partial carboxylation of polyvinylamine. Cotton fabric was pretreated with polyamino carboxylic acids and dyed with reactive dyes. The colour strengths of the dyed fabrics were evaluated by measuring the K/S values. The fastness properties (washing, rubbing and light fastness) of the dyed cotton fabrics were also measured. The pretreatment of cotton with polyamino carboxylic acids creates positive charges on the fabric surface. In this way, salt‐free reactive dyeing of cotton or dyeing with only a small amount of electrolyte is possible.     

Dyeing properties of cotton fibres treated with liquid ammonia

Both scoured and sodium hydroxide mercerised cotton fibres have been treated with liquid ammonia atndash33.4°C using commercial operating equipment and then the ammonia removed at 130°C in a hot drum. The moisture regain and water absorbency of the fibres treated with liquid ammonia were increased compared with values on untreated fibres, whereas both these parameters on mercerised cotton fibres were decreased by subsequent liquid ammonia treatment. The fibres were dyed with CI Direct Red 2 and CI Direct Blue 1. Liquid ammonia treatment of the scoured cotton fibres increased the rate of dyeing, equilibrium dye adsorption, standard affinity, heat of dyeing and change of entropy, while the dyeing properties of mercerised cotton were adversely affected by subsequent liquid ammonia treatment.     

Application of a fibre-reactive chitosan derivative to cotton fabric as a zero-salt dyeing auxiliary

Cotton fabric has been treated with a fibre-reactive chitosan derivative containing quaternary ammonium groups, O -acrylamidomethyl- N -[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride (NMA-HTCC). Cotton treated with NMA-HTCC has been dyed with direct and reactive dyes without the addition of salt. The colour yield was higher than that on untreated cotton, despite the addition of a large amount salt in the latter case. After dyeing, cotton treated with NMA-HTCC gave better wash fastness than the untreated cotton. The light fastness was however inferior to that on untreated cotton. The antimicrobial activity of cotton treated with NMA-HTCC against Staphylococcus aureus was considerably lower after dyeing, probably due to the antimicrobial effect of the cationic group on NMA-HTCC being blocked by its combination with the anionic dye.     

Alkaline dyeing of polyester and polyester/cotton blend fabrics using sodium edetate

An alkaline dyeing of polyester with an alkali‐stable disperse dye, Dianix® Scarlet AD‐RG, was developed using sodium edetate as an alkaline buffering agent. The results obtained indicate the suitability of using sodium edetate for alkaline dyeing of polyester when compared with the control alkaline dyeing using Dianix AD system. Selected mono and bifunctional reactive dyes were used in combination with the alkali‐stable disperse dye for dyeing of polyester/cotton blend. Different dyeing methods for cotton and polyester/cotton blend fabrics using sodium edetate were evaluated in comparison with their respective control alkaline dyeing methods. The results of using sodium edetate in one‐bath two‐stage and two‐bath dyeing of polyester/cotton blend were comparable with that of the control dyeing method. Particularly, no change in the leveling and fastness properties was evaluated for all samples irrespective of the dyeing method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

偶氮染料的光还原脱色及其染色废水的回用研究

用还原脱色剂对水溶性偶氮染料进行光还原脱色降解,重点考察了还原脱色剂、辐射光以及染料浓度等对还原脱色反应的影响,并将脱色后的染色废水回用于棉织物染色中.结果表明,以适当比例的引发剂和促进剂组成的还原脱色剂具有较强的脱色降解能力,辐射光对染料的还原脱色反应具有明显的促进作用,染料浓度的提高不利于染料的脱色降解反应.脱色废水可以回用于棉织物的活性染料染色中,通过降低染色过程中氯化钠和碳酸钠的添加量,可使染色试样与自来水染色试样的总色差(DE*)＜1.0.     

Cetylpyridinium chloride cationic finishing improves the dyeing and antibacterial properties of madder dyed cotton

In this work, after cationic pretreatment of cotton fabric with cetylpyridinium chloride (CPC), the compound of citric acid (CA) and succinic acid (SUA) were used as crosslinking agents to dye cotton fabrics with natural madder dye to improve the dyeing and antibacterial properties and realise the multifunctional finishing of cotton fabric. The effects of mordant dyeing, CA + SUA crosslinked dyeing, and CPC/CA + SUA crosslinked dyeing on the microstructure and properties of cotton fabrics were compared. The dyeing by the three processes occurred primarily in the amorphous zone of the fibres, and all kept the original crystalline form of the cotton. CA + SUA crosslinked dyeing and CPC/CA + SUA crosslinked dyeing increased the thermal stability of the cotton fabric. CPC/CA + SUA crosslinked dyed cotton obtained excellent dyeing results with the colour depth value (K/S) of 12.3 and rubbing fastness and washing fastness of levels 4–5, and the levelness and dye permeability were acceptable. Furthermore, the antibacterial rate against Escherichia coli and Staphylococcus aureus reached 99.99%, and the ultraviolet protection factor (UPF) reached 50+. Moreover, the wrinkle recovery angle (WRA) increased by 55% compared with raw cotton. This showed that CPC/CA + SUA crosslinked dyed cotton had excellent antibacterial, anti-ultraviolet, and anti-wrinkle performances.     

Improving the environmental and economic aspects of cotton dyeing using a cationised cotton†

One approach to improve the affinity of anionic dyes for cotton is to add cationic dye sites to the fibre. The dyeing behaviour of cotton that had been rendered cationic by reaction with 2,3‐epoxypropyltrimethylammonium chloride was examined. Dye yields and fastness properties are reported for a number of direct, reactive and acid dyes with the modified fibre. Excellent dye yields and colour fastness properties were obtained without the use of electrolytes, multiple rinsings or fixation agents which are normally employed in cotton dyeing.     

Using carbon black nanoparticles to dye the cationic‐modified cotton fabrics

Carbon black (CB) aqueous dispersion was prepared and used to dye the cationic‐modified cotton fabrics through exhaust dyeing process. The effects of CB concentration, CB nanoparticles size, dyeing bath pH, dyeing time and dyeing temperature were investigated. The color yields of dyed fabrics were evaluated on Kubelka‐Munk value K/S. The surface morphologies of cationic modified and nonmodified cotton fabrics were measured by video microscope. The fabrics presented 18.9 of the color yield with the dyeing conditions: the dyeing solution contained 2% o.w.f. CB and dyeing at 80°C for 30 min with pH 13 using a 50 : 1 liquor ratio. The images of the video microscope demonstrated a clear surface profile for the cationic‐modified cotton fabrics dyed with smaller CB particle size solutions. These results indicated that CB nanoparticles were suitable for dyeing the cotton fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Application of phthalimide-based alkali-clearable azo disperse dyes on polyester and polyester/cotton blends

Phthalimide-based alkali-clearable azo disperse dyes were synthesised and applied to polyester and polyester/cotton blends. These dyes have an alkali-clearable property that enables alkaline treatment to be substituted for conventional reduction clearing. Therefore, by using these dyes, it is possible to avoid generating dyehouse effluents with high BOD values and carcinogenic aromatic amines that may, in some cases, be liberated by reduction clearing. In addition, polyester/cotton blends can be dyed by a one-bath, two-step dyeing method, as alkali clearability enables the disperse and reactive dyes to be used in the same bath. The dyeing behaviour and fastness properties of these dyes have been investigated. In particular, the cross-staining of cotton was studied to estimate the suitability of the dyes synthesised for dyeing polyester/cotton blends.     

PLA/棉混纺织物一浴一步法染色

本文通过研究聚乳酸纤维的染色工艺特点,探讨国内外涤/棉、PLA/棉混纺织物染色工艺技术进展,分析分散/活性染料一浴一步法染PLA/棉混纺织物存在的技术问题,提出了适合PLA/棉一浴一步法染色的染料及染色方法,并对一浴一步法染色的前景做了展望.