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.     

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.     

Using ecological reducing agents instead of sodium sulphide in dyeing with CI Sulphur Black 1

Although low‐cost sodium sulphide is used as a reducing agent in most sulphur dyeing processes, it is considered to be environmentally unfavourable because of the resultant contaminated wastewater and the toxic hydrogen sulphide generated during the dyeing process. In the present paper, hydrazine sulphate, glucose, and sodium borohydride in the presence of sodium hydroxide were used as ecologically safe reduction systems for the CI Sulphur Black 1 dyeing of cotton fabric, and results were compared with those obtained using sodium sulphide. Dyeing processes were carried out at 90 °C for 60 min, and the colour yield (the K/S value), dyeing fastness, and breaking strength of dyed fabrics after soaping were measured. Response surface methodology was employed for experimental design and optimisation of results. Mathematical model equations were derived and statistical analysis carried out by computer simulation programming using Minitab v.15. At a dosage of 0.8 g l^?1 of CI Sulphur Black 1, the optimum sodium borohydride reduction system (sodium borohydride 0.47 g l^?1, sodium hydroxide 0.65 g l^?1) exhibited the highest colour yield and the lowest chemical oxygen demand of the residual dyebath.     

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     

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.     

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.     

One-bath dyeing of a polyester/cotton blend with reactive disperse dyes from 2-hydroxypyrid-6-one derivatives

A series of temporarily solubilised reactive disperse dyes based on 1-substituted derivatives of 2-hydroxypyrid-6-one were applied to a 65;35 polyester/cotton blend using a one-bath dyeing method without dispersing agent. The dyeing behaviour of these dyes on polyester and cotton fabrics, and polyester/cotton blend fabric, were studied. The colour yields of the dyes on the polyester/cotton blend were found to be highly dependent on the initial pH, optimum results being obtained at pH 5. Good levelling and good to excellent fastness properties were obtained on the blend, with the exception of lightfastness, which was moderate.     

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.     

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.     

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.     

降解壳聚糖在棉织物活性染料低盐染色中的应用

采用降解壳聚糖对棉织物进行预处理,比较处理前后棉织物活性染料染色的上染率、固色率及耐摩擦牢度,在此基础上研究低盐工艺对棉织物活性染料染色的上染率、固色率的影响。实验结果表明降解壳聚糖预处理棉织物显著改善活性染料染色性能,提高染料上染率,减少了染整加工过程中对环境造成的污染。降解壳聚糖预处理的最佳工艺条件:浸渍温度80℃、降解壳聚糖用量0.8%(owf)、浸渍时间30 min。     

Analysis of the factors influencing dye uptake on jet dyeing equipment

Machine parameters that possibly influence the dye-uptake rate on textile jet dyeing equipment are reviewed in this study. Some of these parameters can be adjusted on a pilot-scale jet machine so as to reproduce bulk conditions, whereas others cannot. It was impossible, for example, to simultaneously achieve appropriate values for the nozzle flow velocity and the dyebath circulation time. The fabric–liquor interchange in the storage area of the machine was also different on pilot scale and on bulk scale. Experiments on a pilot machine with a direct dye on cotton yielded, for most cases, no influence of fabric speed and dyebath flow rate on the dye-uptake rate despite high substantivity conditions. Only when the flow rate dropped below 50 dm³ min⁻¹ kg⁻¹, the exhaustion rate diminished approximately proportionally to the square root of the flow rate, probably because of dye depletion in the storage chamber. On the pilot machine, the jet nozzle did not appear to contribute to the overall fabric–liquor interchange. Implications for bulk jet dyeing machines are discussed.     

Investigations on the level dyeing of fabrics in supercritical carbon dioxide

The level dyeing of fabrics in supercritical carbon dioxide was investigated by employing an improved beam (a perforated pipe on which the knitted or woven fabric/warp is wound around). The effects of system temperature, pressure, dyeing time, a time ratio of fluid circulation to static dyeing (R_time), different fabric layers wrapped around the beam, and the species and chemical structures of dyestuffs on leveling properties and color strength of polyester and cotton fabrics were observed. The results show that the leveling properties and color strength of fabrics were improved on the new beam, as well as with a favorably increased system temperature, pressure, dyeing time, and a time ratio of fluid circulation to static dyeing; while the leveling property and color strength decreased with fabric layers on the beam under an identical condition. Highly leveling results were obtained on polyester and cotton fabrics with disperse and reactive disperse dyes involving different chemical structures.     

Reuse of ash-tree (Fraxinus excelsior L.) bark as natural dyes for textile dyeing: process conditions and process stability

The aqueous extract of ash-tree bark ( Fraxinus excelsior L.) was chosen as a model to study the shade reproducibility of dyeing on wool. A meta-mordanting process using FeSO₄·7H₂O mordant was chosen as a system with particular potential for industrial application. The exhaust dyeing process with immediate use of the extracts as a dyebath and direct addition of FeSO₄·7H₂O stock solution as a meta-mordant process showed good shade reproducibility and satisfying levelness of the dyed material. An increase of Fe( ii )-mordant above a dyebath concentration of 2–3 g l⁻¹ did not result in further colour depth. Extraction of 1–2 g of bark was found sufficient to dye 1 g wool yarn to the darkest colour possible; use of higher amounts of bark did not yield substantially higher colour depth. The quality of bark and the extraction step were found to be of significant importance for the colour depth; thus, in an optimised process, conditions of extract formation have to be well controlled.     

Telechelic PEG-polymers end-capped with chromophores: Using as cationic reactive dyes and salt-free dyeing properties on cotton fabrics

In this article, telechelic polymers containing polyethylene glycol (PEG) moieties as space groups were combined with chromophores to synthesize cationic reactive dyes (BCD-R, BCD-Y, and BCD-B). The salt-free dyeing performance of these telechelic polymeric cationic reactive dyes on cotton fabrics was evaluated. The exhaustion and fixation of the dyes in salt-free dyeing was above 89.33 and 77.22%, respectively. The color fastness of dry rubbing for the three dyes reached grade 4–5, and their color fastness to light reached grade 5–6. Their washing fastness also reached grade 4–5, except for that of BCD-Y (grade 3–4). The results showed that the dyes possessed good leveling and build-up properties and substantivity to cellulose fiber. The zeta potential (ξ-potential) of dyed fabric was estimated, and it was found that the ξ-potential of the fabrics increased after dying with telechelic polymeric cationic reactive dyes, and the more dye that was used, the greater ξ-potential increase. The exhaustion curves of dyes were also determined, and they were much different from those of anionic reactive dyes. The adsorption kinetics and isotherms of BCD-R were investigated. It was found that the pseudo-second-order kinetic model gave the best fit of the experimental data at all three tested dyeing temperatures (25, 45, and 65°C) with R² values over 0.998. Both the Langmuir and Freundlich models could be used to describe the adsorption of BCD-R onto cellulose fibers and the Langmuir model fit the experimental data better than the Freundlich model. The thermodynamic parameters (ΔG, ΔS, ΔH, and activation energy) of the dye adsorption process were researched further. The results indicated that the adsorption of BCD-R onto cotton fibers was spontaneous and exothermic and that after adsorption onto the cotton fibers, the degree of freedom of the dye decreased.     

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.     

硅氧烷低聚物的合成及其在泡沫染色中的应用

为了通过泡沫染色和光固化改善棉织物的染色性能，合成了一种含有不饱和双键的硅氧烷低聚物，设计了合适的含有聚合型黄色蒽醌染料、硅氧烷低聚物、光引发剂2,4,6-三甲基苯甲酰基-二苯基氧化膦（TPO）、表面活性剂十二烷基硫酸钠（SDS）的泡沫体系对棉织物进行泡沫染色。采用1HNMR和GPC分析了硅氧烷低聚物的化学结构和相对分子质量分布，采用FTIR表征了硅氧烷低聚物和染色棉织物的化学结构，采用SEM观察染色棉织物的表面形态。探讨了硅氧烷低聚物用量、染料用量、SDS质量浓度、TPO用量对泡沫性能和染色性能的影响，分析了硅氧烷低聚物的固色机理。结果表明，染料质量浓度30 g/L、硅氧烷低聚物用量为染料质量的2倍、SDS质量浓度2.0 g/L、TPO用量为染料质量的5%、紫外光照时间5 min时，染色织物染色深度可达5.70，耐皂洗色牢度和干/湿摩擦色牢度均为4～5级，水接触角为110.1°，紫外防护系数>50。硅氧烷低聚物通过侧基上的不饱和双键发生自由基聚合和硅醇基偶合交联实现固色，并赋予织物良好的疏水性能和抗紫外线性能。     

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     

Reactive dyeing of cationized cotton: Effects on the dyeing yield and the fastness properties

The cationization of cotton fibers is emerging as an effective tool for solving the environmental problems associated with the dyeing of cotton fabrics with anionic dyes. In this study, the dyeing performance of cationizing agents (Rucomor Bur, Kemifix REA, Optifix F, and Optifix RSL) were examined, and we found that this method had better results compared with normal or existing methods of reactive dyeing. The dye‐bath exhaustion and fixation were determined by the help of an ultraviolet–visible absorbance spectrophotometer on the basis of the maximum absorbance wavelength. Better fixation values were found with the cationizing process than with salty dyeing. The washing and rubbing fastness results were as the same as those of traditional dyeing. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Research in the cold pad–batch dyeing process for wool pretreated by hydrogen peroxide

The cold pad–batch dyeing process of wool pretreated by hydrogen peroxide was carried out with Lanasol reactive dyes and Realan reactive dyes. The influences of various conditions of the dyeing process, including urea dosage, sodium bisulphite dosage, pH value, batching time and the liquor pickup on colour yield, were analysed. Fixation, levelness of dyeing, dye penetration, colour fastness, breaking strength and elongation were compared between untreated and treated wool fabrics. The study showed that cold pad–batch dyeing of wool fabric is a good prospect for future use because of the resulting advantages, such as higher fixation yield, less energy usage and lower sewage discharge.