Dispersant‐free dyeing of poly(lactic acid) fabric with temporarily solubilised disperse dyes from azopyridone derivatives

Poly(lactic acid) fibre is derived from annually renewable crops and known to be 100% compostable. In order to extend its environmental friendliness into the dyeing process, dispersant‐free dyeing of poly(lactic acid) fabric with three temporarily solubilised azo disperse dyes based on hydroxypyridone moiety containing a β‐sulphatoethylsulphonyl group was investigated. The dyes were successfully applied to poly(lactic acid) fabric without the use of dispersants. The colour yields of the dyes on poly(lactic acid) fabric were observed to be dependent on dyebath pH and dyeing temperature. The optimum results were obtained at pH 4–5 and 110 °C. One of the dyes showed a colour yield as good as that of a commercial disperse dye and good build‐up on poly(lactic acid) fabric. All of the dyes could be alkali cleared owing to ionisation of the dye under mild alkaline conditions. Wash fastness was good to very good, and light fastness was good. The chemical oxygen demand levels of the poly(lactic acid) dyeing effluent from the dyes were considerably lower than those from a commercial disperse dye.     

Dyeing of wool with temporarily solubilised disperse dyes

Temporarily solubilised disperse dyes derived from aminophenyl-4-(β-sulphatoethylsulphone) have been applied to wool fabric without the use of a levelling agent. By virtue of their characteristic dye structure, excellent levelling properties were observed on wool fabric. Good exhaustion, fixation and fastness test values were also obtained.     

Aftertreatment of polyester fabric dyed with temporarily solubilised disperse dyes

Temporarily solubilised disperse dyes derived from aminophenyl-4-(β-sulphatoethylsulphone) are exhausted on the polyester fibre mostly in the vinylsulphone form and to a lesser extent as their hydroxyethylsulphone analogues. After dyeing, to remove the unexhausted dyes on the polyester fibre, sulphite anions were added to the dyebath. The vinylsulphone residue of the dye was attacked by the sulphite anion via an addition reaction converting the dye into a soluble derivative, which then had little affinity for the polyester fibre. The effect of sodium sulphite on the conversion of the dye was investigated using HPLC. The wash and rub fastness properties of the dyed fabric aftertreated with sodium sulphite were similar to those obtained with reduction clearing.     

Dispersant-free dyeing of polyester with temporarily solubilised azo disperse dyes from 1-substituted-2-hydroxypyrid-6-one derivatives

Four temporarily solubilised azo disperse dyes based on 1-substituted-2-hydroxypyrid-6-one were synthesised and characterised. The dyes showed high extinction coefficients and had a yellow shade on polyester fabric. They were successfully applied to polyester without the use of dispersants and the optimum pH was found to be 5. It was found that the dyes could be alkali-cleared due to ionisation of the dye under mild alkaline conditions. The dyes exhibited good to excellent fastness properties on the polyester fabric.     

The dyeing of nylon with a microencapsulated disperse dye

Melamine resin microcapsules containing CI Disperse Blue 56 were prepared by in situ polymerisation. The microcapsules were characterised by their thermal properties and morphology, such as particle size and particle size distribution. The dyeing behaviour of the microcapsules on nylon 6.6 was evaluated. The microencapsulated dye exhibited good build-up, levelness and fastness properties. It has been demonstrated that microencapsulated disperse dye can be used to replace commercial disperse dyes in dyeing polyamide fabric without dyeing additives, and the resulting effluent can be easily recycled after filtration.     

Dyeing of nylon 6 fabric with a bifunctional sulphatoethylsulphone reactive disperse dye

A bifunctional reactive disperse dye containing two temporarily anionic sulphatoethylsulphone groups was synthesised and applied to nylon 6 fabric by exhaust dyeing at a variety of pH levels and temperatures. A monofunctional reactive disperse dye containing one temporarily anionic sulphatoethylsulphone group was also synthesised, and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and total fixation yield under alkaline conditions. The results also indicate that the introduction of two temporarily anionic sulphatoethylsulphone groups of the bifunctional dye gave an enhancement in dyeing performance compared with that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.     

Effect of microencapsulation on dyeing behaviors of disperse dyes without auxiliary solubilization

Microencapsulated disperse dye can be used to dye hydrophobic fabric in the absence of auxiliaries and without reduction clearing. However, little available information for dyeing practice is provided with respect to the effect of microencapsulation on the dyeing behaviors of disperse dyes. In this research, disperse dyes were microencapsulated under different conditions. The dyeing behaviors and dyeing kinetic parameters of microencapsulated disperse dye on PET fiber, e.g., dyeing curves, build up properties, equilibrium adsorption capacity C_∞, dyeing rate constant K, half dyeing time t_1/2, and diffusion coefficient D were investigated without auxiliary solubilization and compared with those of commercial disperse dyes with auxiliary solubilization. The results show that the dyeing behaviors of disperse dye are influenced greatly by microencapsulation. The diffusion of disperse dyes from microcapsule onto fibers can be adjusted by the reactivity of shell materials and mass ratios of core to shell. The disparity of diffusibility between two disperse dyes can be reduced by microencapsulation. In addition, the microencapsulation improves the utilization of disperse dyes due to no auxiliary solubilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Dyeing of nylon 6 fabric with a new bifunctional vinyl sulphone reactive disperse dye

A new bifunctional reactive disperse dye containing a temporarily anionic sulphatoethylsulphone and a nonionic disulphide bis(ethylsulphone) groups was synthesised and applied to nylon 6 fabric by the exhaust dyeing at a variety of pH and temperature conditions. A monofunctional reactive disperse dye containing only nonionic disulphide bis(ethylsulphone) group was also synthesised and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and fixation values at pH 6 and 120 °C. The results also indicate that the combination of temporarily anionic and nonionic reactive groups of the bifunctional dye provided great enhancement in dyeing performance compared to that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.     

Synthesis,spectral and dyeing properties of phenylazopyrazolone‐containing acylamide disperse dyes designed for poly(lactic acid)

A series of phenylazopyrazolone disperse dyes containing an acylamide moiety were synthesised from carboxyl‐containing acid dyes via chlorination and amidation with different sorts of amines. The structures of these new dyes were confirmed by Fourier Transform–infrared, proton nuclear magnetic resonance, mass spectroscopy and elemental analysis. Their solvatochromic properties in different solvents were also investigated and the absorbance spectra of the acylamide dyes in solution exhibited a red shift when dissolved in dimethylformamide, compared with acetone. Their dyeing behaviour, including dye sorption, colour build‐up and colour fastness properties on poly(lactic acid) fibres, was also determined, whereupon it was found that the tertiary acylamide dyes simultaneously exhibited high dye sorption and satisfactory colour build‐up and fastness properties on the poly(lactic acid) fabric.     

Study of the removal of a disperse dye stain from a polyester/elastane blend

Polyethylene terephthalate and elastane fabrics were treated with azo disperse dyes in the same dyebath at 130 °C for 0, 30 and 60 min and then reduction cleared. The dyes adsorbed on each fabric were extracted using monochlorobenzene, in order to determine the amount of disperse dye in each of the polyethylene terephthalate and elastane fabrics, as the dyeing time was increased. It was observed that the amount of dye on the polyethylene terephthalate increased, while that on the elastane decreased, as the time at 130 °C increased from 0 to 60 min. After reduction clearing, the partition ratio of disperse dyes between the polyethylene terephthalate and the elastane increased. The dyed polyethylene terephthalate/elastane blend indicated that those dyes, which exhibited high partition ratios (polyethylene terephthalate:elastane), exhibited correspondingly higher wet fastness properties.     

浅谈分散染料染色残液COD

该文通过打小样试验,挑选适用于碱性染色工艺和弱酸性染色工艺的两种不同染料各九支,并结合实际生产中大部分染厂所用工艺,应用三种不同工艺对涤纶织物进行上染,收集染色残液测量pH和COD．使用碱性染色工艺,染液在织物上染前后pH值有变化,残液pH值达到GB4287—92中的相关规定;使用弱酸性染色工艺和染厂所用工艺,染液在织物上染前后pH基本没有变化．对比三种工艺收集残液的COD值,发现使用碱性染色工艺的分散染料,收集的残液COD明显偏低。这为大生产中印染厂优化染色工艺、节能减排、降低综合成本提供了试验依据。     

Influence of different finishing conditions on the wet fastness of selected disperse dyes on polylactic acid fabrics

This study investigates the influence of different finishing conditions on the amount of thermal migration and the wet fastness properties of selected red disperse dyes on polylactic acid fabrics. A comparison was made with a correspondingly finished polyethyleneterephthalate fabric, with a specific objective being to identify the conditions that would give optimum wet fastness to the polylactic acid fabric. A greater thermal migration of dye was observed on the polylactic acid compared with polyethyleneterephthalate fabric under the same heat treatment conditions, resulting in a lower level of wet fastness. The lowering in wet fastness of dyed polylactic acid fabric on processing occurs mainly as a result of thermal migration of disperse dyes during the drying stage at 110 °C.     

VIS absorption spectrophotometry of disperse dyes

In the investigations of the dyeing processes, the low solubility of disperse dyes in water represents a practical problem for the determination of dye concentration in dyebaths and waste waters. Therefore the use of an organic solvent which, dissolves disperse dyes, is recommended in visible spectrophotometry of disperse dyes. Three organic solvents (ethanol, N,N-dimethylformamide, acetone) and two disperse dyes, the disazo dye C.I. Disperse Orange 29 and the anthraquinone dye C.I. Disperse Blue 56, were used for spectroscopic analysis in this present work. The absorbance of aqueous dye dispersions and various organic solvent dye solutions was measured to evaluate the effect of the solvent on the shape and intensity of the absorption spectra and on the wavelength shift of maximum absorption. The validity of Beer–Lambert’s law in each system was ascertained. A suggestion is made how VIS absorption spectrophotometry can be used to determine the dye concentration in disperse dyebaths. The addition of organic solvent to the dyebath leads to dye dissolution, and the Beer-Lambert’s law is then fulfilled. The optimum ratio between the dyebath dispersion and the organic solvents for the dyes investigated is also determined.     

Effect of Sandospace R on the dyeability of gamma-irradiated wool,wool/polyester and polyester fabrics with some disperse dyes containing amino groups

The effect of Sandospace R on the dyeability of gamma-irradiated wool, wool/polyester and polyester fabrics towards disperse dyes has been investigated. The effects of the different factors that may affect the colour yield of the dyed samples (such as radiation dose, Sandospace R concentration, pH strength of the dye bath, dye concentration, dyeing temperature and time were studied. In general, and regardless of the studied factor, the irradiated fabric showed a significant dye affinity for the disperse dyes employed compared/to the unirradiated fabrics. However, the different fabrics irradiated to a dose of 2Mrad showed the highest colour strength with a high level of dyeing. Also, it was observed that a concentration of Sandospace R as low as 0·5% effectively enhances the dye affinity for the disperse dyes used here. Moreover, it was found that the pH of the dyeing bath at which the highest colour strength obtained was 3. Increasing the dye concentration up to 4% based on fabric weight, caused a significant enhancement in the colour strength, whilst raising/the dyeing bath temperature from 60°C to 100°C appreciably accelerated the rate of dye uptake. Complete exhaustion absorption of the disperse dye occurred over a period of 2h. © 1998 Society of Chemical Industry     

Dyeing of polyester using micro-encapsulated disperse dyes in the absence of auxiliaries

Polyurea microcapsules were prepared in this study, using disperse dye as the core material and diphenylmethane-4,4'-diisocyanate as the wall-former. Microencapsulated disperse dyes have been characterised in terms of their thermal properties, average particle size and size distribution, morphological structure and composition. Polyester fabric was dyed with microencapsulated CI Disperse Blue 56 using a high temperature dyeing process without dispersing agents, penetrating agents, levelling agents or other auxiliaries. The quality of the polyester fabric dyed in this manner – without reduction clearing – was at least as good as that dyed traditionally after washing and reduction clearing. After separating off the polyurea microcapsules, the dyebath was virtually colourless and was shown to be suitable for reuse.     

Synthesis of reactive disperse dyes containing halogenated acetamide group for dyeing cotton fabric in supercritical carbon dioxide

A series of reactive disperse dyes incorporating halogenated acetamide group were synthesized and applied to dye cotton fabric in supercritical carbon dioxide (scCO₂). Dyeing experiments were conducted in scCO₂ with dye concentration of 0.5% owf (% on weight of cotton fabric), varying from 80 to 120 °C, for 1–3 h at a constant pressure of 200 bar. The results showed that the color strength of dyed cotton fabric increased favorably when increasing temperature and time. The color characteristics were studied as well in terms of the reflectance spectra. And the color fastness to washing and rubbing were also reasonably good.     

Use of a novel water-soluble arylating agent to dye wool and wool blends with disperse dyes

A series of water-soluble fibre-reactive arylating agents were synthesised and evaluated from the stand-point of improving fibre coloration with disperse dyes. In particular, the compound, sodio-2,4-dianilino-6-[4'- β -sulphatoethylsulphonylanilino]- s -triazine (FAA 200) was found to be promising; this compound could be applied in the same bath as a disperse dye at pH 5–6. Under the latter conditions this compound showed high substantivity to wool and at the boil readily underwent β -elimination of the sulphate ester residue to give the vinyl sulphone reactive group which adds on to nucleophilic sites in the fibre to form a covalent bond. Coapplication with commercially available disperse dyes gave bright, level dyeings that exhibited promising wet fastness. FAA 200 was used as an auxiliary to dye disperse dyes on both fibre components of a wool–polyester blend fabric; it was found that addition of hydrogen peroxide or sodium thiocyanate was necessary to obviate reduction of certain disperse dyes when dyeing at 120 °C.     

Vapor phase dyeing of synthetic fibers with disperse dyes

Dyeing of synthetic fibers by the heat transfer process of disperse dye vapors is performed by contacting white receptor polyester or polyamide fabric with other dyed polyester fabrics (donor) under the influence of heat. The dye vapours flowing away will diffuse across the very slight air gap enclosed between the inner donor and receptor surfaces under the applied pressure. It is found that the dye uptake by the receptor fabric is dependent on the original dye content of the donor fabric, transfer temperature and dwell time. The released dye from the donor fabric under the influence of heating is found to be dependent on the original dye content of the donor fabric as well as the transfer temperature. The efficiency of the dye transfer is also attributed to the original shading of the donor fabric. Evaluation of the imparted colors on the receptor fabric (polyester, polyamide) obtained by heat contact with the same donor fabric showed visually the same colour level up to the 13th run. Thermodynamic interpretation of the standard affinity (Δu⁰) and heat of dyeing (ΔH⁰) as well as the partition coefficient of the dye show that the dyeing process has an exothermic character. The rate controlling step in this dyeing process is found to be dependent on the diffusion of the dye vapors into the fiber phase.     

Synthesis of temporarily solubilised azo disperse dyes containing a β‐sulphatoethylsulphonyl group and dispersant‐free dyeing of polyethylene terephthalate fabric

Disperse dyes containing a β‐sulphatoethylsulphonyl group have temporary solubility and can be applied for dispersant‐free dyeing of hydrophobic fibre. Six novel temporarily solubilised azo disperse dyes having a β‐sulphatoethylsulphonyl group in their structures were synthesised, and their dyeing properties on polyester were investigated. As a dye intermediate, a diazo component having dibromo groups was prepared, and 4‐diethylamino‐4′‐(2‐sulphatoethylsulphonyl‐4,6‐dibromo)azobenzene dyes were prepared by a diazo‐coupling reaction. Then, the dyes containing dicyano groups were prepared by cyanation of corresponding dyes with dibromo groups. The absorption maxima of the dyes were affected by the substituents in the diazo and coupling component rings and varied from 434 to 616 nm in dimethylformamide. Polyethylene terephthalate woven fabric could be dyed with the synthesised temporarily solubilised dyes without using any dispersants. Dyebath pH affected the K/S value at maximum absorption as well as percentage exhaustion on polyethylene terephthalate fabric, and the optimum pH was 5. The dyes gave brownish orange, red, purple, and greenish blue hues on polyethylene terephthalate fabrics, and colour build‐up was good. Wash fastness was good to excellent, rubbing fastness was moderate to excellent, and light fastness was poor to moderate.     

The dyeing of poly(lactic acid) fibres with disperse dyes using ultrasound: Part 1 - Initial studies

Six disperse dyes were applied at 0.5%, 1% and 2% omf depths of shade to poly(lactic acid) fabric at 30-80 °C for 20, 50 and 90 min in both the presence and absence of ultrasound. Whilst ultrasound enhanced the colour strength obtained for three of the six disperse dyes used at temperatures upto 70 °C, ultrasound did not always result in enhanced colour strength being achieved in the case of the three other dyes. The observed intensification of colour strength was attributed to dye disaggregation. Dyeing at 80 °C in the presence of ultrasound resulted in pale, dull dyeings of reduced colour strength, which was attributed to breakdown of the dye dispersions at this particular temperature.