Novel yellow azo–anthraquinone dyes for polylactide fibres: effects of alkyl chain length

1‐(4′‐Alkylaminosulphurylphenyl)‐3‐methyl‐5‐pyrazolonyl azo–anthraquinone dyes were prepared in four steps from 1‐aminoanthraquinone, as an approach to enhancing the exhaustion levels of disperse dyes on polylactide fibres. Their structures were confirmed from combustion analysis and mass spectrometry, infrared and proton nuclear magnetic resonance spectroscopy. Results from artificial intelligence‐based molecular modelling studies showed that increasing alkyl chain length gave an increase in LogP, molecular volume and aplanar shape. Their application to polylactide fibres led to both good per cent exhaustion values and good light fastness ratings. It was also found that the nature of the alkyl chains attached to the phenyl ring had little influence on dye colour, but clearly influenced per cent exhaustion and wash fastness.     

疏水性葸醌染料在聚乳酸织物上的染色性能

The dyeability of polylactide fabric has been investigated with the substituted aminoanthraquinone hydrophobic dyes.Their application to the polylactide fabric led to good exhaustion values and good wash fastness between 4 and 5.Microscopic assessment of cross-sections of the dyed polylactide fibres confirmed that these dyes could penetrate into the fibres.The nature of the substituted amino groups showed little influence on the wash fastness,but clearly influenced the exhaustion and light fastness.     

Synthesis and properties of acid dye derivatives of arylsulphonanilides

Thirty-five acid dyes suitable for dyeing wool and polyamide fibres were synthesized, using derivatives of arylsulphonanilides prepared from o-nitrotoluene or chloronitrotoluene. As coupling components, derivatives of 1-phenyl-3-methylpyrazolone-5 and 2-naphthol were used. Fastness and colour properties of the prepared dyes were determined. It was found that some of the prepared dyes on polyamide fibres show batho- and hypso-chromic effects as well as hypo- and hyper-chromic effects during testing of their fastness to washing and to acid and alkaline perspiration. Spectroscopic examinations and determination of pK_a of the sulphonamide and hydroxyl groups of the dyes showed that the observed changes are associated with aggregation or disaggregation of the dyes on fibres or with a change in the azo-hydrazone equilibrium. Some of the prepared dyes are characterized by very good dyeing and fastness properties.     

Synthesis,spectral properties and dyeing on polyester of monoazo dyes from indol‐2‐one derivatives

Three series of phenylazo disperse dyes were prepared by coupling diazotised 4‐aniline dyes with 5‐indol‐2‐one dyes. The structures of these dyes were determined by proton nuclear magnetic resonance, Fourier Transform–infrared and elemental analysis. The effects of solvent on the ultraviolet–visible absorption spectra of these dyes were studied. The dyes displayed a λ_max shift of between 399 and 438 nm. The dyes were finally applied in the dyeing of polyester fibres in order to investigate their colour range and dyeing properties. Most of the dyes displayed high rubbing fastness and good washing and sublimation fastnesses on polyester fibres.     

Synthesis of methine dyes derived from indol‐2‐ones and their dyeability on polyester fibres

Three series of methine dyes were synthesised by the condensation of indol‐2‐ones with aryl acroleins. The structures of these dyes were confirmed by ¹H nuclear magnetic resonance spectroscopy, infrared spectrometry and elemental analysis. The ultraviolet‐visible absorption spectra of the dyes were examined in different solvents. The maximum absorption wavelength ranged from 386 to 495 nm. The dyes were applied to polyester fibres, and the colour gamut and dyeing properties were investigated. Results showed that the dye uptake (percentage exhaustion) was 86.9–92.0%, with the hue changing from yellow to red. The rubbing fastness, wash fastness, and sublimation fastness were between 4 and 5.     

Dyeing Properties of Monoazo Dyes Derived from 5-Nitro-2-aminobenzothiazole-3N-oxide on Various Synthetic-polymer Fibres

The preparation of new monoazo dyes from substituted 5-nitw-2-aminobenzothiazole-3N-oxides and aniline coupling components and their dyeing properties on polyester, cellulose acetate, nylon 6 and acrylic fibres are reported. The dyes exhaust well on synthetic-polymer fibres to give bright dyeings of good fastness to dry cleaning and sublimation. Their light fastness is better than that of dyeings of the unnitrated dyes. However the transferability of the nitro dyes is such that they are unsuitable for sublimation printing. The transferability of other dyes derived from 2-aminobenzothiazole-3N-oxide and its derivatives is also assessed.     

A systematic study of dyeing polybutylene succinate fibres

Biodegradable polybutylene succinate (PBS) fibre is a new type of textile fibre, but its application in the textile industry is limited by the lack of related dyeing methods. In this study, the solubility parameters of PBS fibres are calculated, and solvent dyes with similar solubility parameters are proposed to dye PBS fibres to show that the dyeing scheme creatively resolves the difficulty in dyeing PBS fibres. The technical parameters of suitable dyes, and the dyeing conditions with ethanol as the dyeing medium, consisted of a dyeing temperature of 90°C, a dyeing time of 30 minutes and a liquor ratio of 30:1. The dyeing results show that the levelling property is good, the dyebath exhaustion is high, and the washing fastness, the rubbing fastness and the perspiration fastness index of the dyed fibres are satisfactory.     

Synthesis and dyeing properties of polyvinylamine dyes for cotton

Novel polyvinylamine dyes were designed and synthesised from poly(N‐vinylformamide‐co‐vinylamine) and reactive dyes, then used to dye cotton fibres by the dip‐pad‐steam process, with the dyeing methods being examined in detail. Each polyvinylamine dye was fixed to cotton without a crosslinking agent through covalent bonds formed between the reactive group of the dye and the cotton fibres. A fixation of 99% was achieved, with grades of 4 and 4‐5 wash and dry‐rub fastness, respectively.     

A study of novel bisazo reactive red dyes with good wet fastness

Three series of bisazo reactive red dyes were synthesised using 6‐amino‐1‐naphthol‐3‐sulphonic acid and its derivatives as the coupling components. The dyeing parameters and wash fastness of these dyes on knitted cotton were evaluated and the relationships between the structure and dyeing properties were investigated. It was found that the hydrophilic groups introduced into the dye molecules decrease the substantivity and fixation of the dyes, but increase the build‐up and migration properties. The defined wash‐off factor can directly reflect the wash fastness of the dyes and the build‐up property can be improved by commercialisation using certain auxiliaries. The results indicate that there is the possibility of synthesising a red reactive dye with a satisfying balance between high fixation and good wash fastness and several such dyes have been developed.     

Dyeing and fastness properties of phthalimide‐based alkali‐clearable azo disperse dyes on poly(ethylene terephthalate)

The properties of a series of phthalimide‐containing azo disperse dyes and azo dyes with N‐methyl phthalimide moieties in their diazo component were investigated and compared when used to colour polyethylene terephthalate. The N‐substitution of the phthalimide gave a hypsochromic effect on the colour change and better colour yields on poly(ethylene terephthalate) fabrics, probably because of the electron‐donating property of the methyl group and the higher hydrophobicity of phthalimide‐containing azo dyes compared with those containing phthalimide moieties. The results show that phthalimide‐based azo disperse dyes have excellent dyeing fastness properties and that high wash fastness can be achieved using alkali clearance. This alternative clearance method is important for reducing the environmental impact of the dyeing process by replacing reductive clearing and, in particular, by removing the need for sodium hydrosulphite, which creates a high biological oxygen demand when released in conventional disperse dyeing effluent and which generates aromatic amines.     

Extraction of polyphenolic dyes from henna,pomegranate rind,and Pterocarya fraxinifolia for nylon 6 dyeing

Acid and disperse dyes are two well‐known synthetic materials that are primarily used for dyeing of nylon 6 fibres. Despite their good performance, several negative impacts on the environment, including air and water pollution, are major concerns to researchers. An alternative ecofriendly approach to the dyeing of nylon 6 is the use of natural dyes, given their abundant natural sources, biocompatibility, biodegradability, non‐toxicity, non‐allergic responses, and non‐carcinogenic effects on human life. Based on these advantages, we extracted polyphenolic dyes from henna leaves, pomegranate rind, and Pterocarya fraxinifolia leaves and studied the dyeability on nylon 6 fabric using three compounds of aluminium sulfate, tannic acid, and tin chloride as toxic and non‐toxic mordants before dyeing. Fourier transform infrared spectra of the nylon 6 fabric confirmed the coordination complexes and π–π bonding between the mordants and the dyes. Colorimetric and fastness results showed that the mordants increased the colour strength and improved the fastness properties of the fibres. Our results suggest that tin chloride and aluminium sulfate as metal mordants can be successfully replaced with tannic acid as a biomordant in the natural dyeing of nylon 6. Also, cost assay showed that dyeing of nylon 6 with extracted natural dyes from waste leaves could be a sustainable and economical substitute for synthetic dyeing.     

Dyeing and antimicrobial studies on polyamine/epichlorohydrin condensate incorporated viscose rayon fibres

Modified viscose rayon fibres were produced by incorporating different doses of polyamine/epichlorohydrin condensate in the dope. The modified fibres show excellent dyeability with heterobifunctional reactive dyes without electrolyte. The wash fastness and the light fastness of the modified fibres dyed with reactive dyes were good. The modified fibres also showed excellent dyeability on dyeing with different acid and metal-complex dyes. The amount of additive present in the fibre was assessed from its nitrogen content and percentage exhaustion was found to increase with increasing quantity of additive. Tonal changes and increase in light fastness with acid and metal-complex dyes have been attributed to the aggregation of dye in the fibre. Fibres containing more than 3% additive in the dope showed greater than 99% bacteria reduction on testing the antimicrobial activity against Escherichia coli and Staphylococcus aureus . It was observed that the antimicrobial activity deactivated on repeated washing using surfactants. The acid-dyed fibres also showed a decrease in antimicrobial activity.     

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.     

Properties of Monoazo Disperse Dyes,Derivatives of 3– and 4–Aminophthalimide

The synthesis of several disperse dyes, from 3–amino–12–phthalimide and its N–methyl derivative as diazo component and N, N–dialky lanilines as coupling component is described. The dyeing behaviour and some physical properties of these dyes are investigated and compared with those of isomeric dyes containing azo groups in the 4–position, previously studied [5]. These properties were found to be considerably affected by the presence of an alkyl sub–stituent on the nitrogen atom of imide group. Further, dyes containing unsubstituted –NH groups showed somewhat better thermal properties (higher melting points and dyeings of better fastness to sublimation), but at the same time their dyeability was worse for all the known processes of dyeing polyester fibres. Based on the i. r. and visible spectra of the dyes under investigation, it was concluded that the dyes containing unsubstituted –NH groups are highly associated; dyes containing azo groups in the 4–position associate to give one product, whereas association of the dyes with azo groups in the 3–position leads to two different products.     

Reactive dyeing of silk using commercial acid dyes based on a three‐component Mannich‐type reaction

Acid dyes are employed for commercially dyeing silk, which results in ionic bonds between the silk fibroin and the dye. This generally leads to low wet fastness properties for dyed silk fabrics. In this work, three commercial acid dyes with aromatic primary amine structures were selected to dye silk using a Mannich‐type reaction, resulting in improved wet fastness of dyed silk by forming covalent bonds between silk fibroin and dye. The Mannich‐type reactive dyeing was applied to silk fabrics at both 30 and 90°C in trials. Dyeing at 90°C can shorten the dyeing time compared with dyeing at 30°C, even although dye exhaustion and relative fixation at 90°C were a little lower. The dyeing process was optimised when the dyeing temperature was 90°C, dyebath pH 4, dye‐to‐formaldehyde ratio 1:30 and holding dyeing time 60 minutes. The results showed that the dye exhaustion on silk fabrics for the three aromatic primary amine‐containing acid dyes exceeded 94% and their relative fixation was over 80%. Their washing and rubbing fastness reached grade 4 or higher. Hence, the colour fastness properties of dyed silk fabrics using the Mannich‐type reactive dyeing method is superior to the conventional acid dyeing method using the same aromatic primary amine‐containing acid dyes. The Mannich‐type reactive dyeing for silk fabrics at 90°C can be developed into a novel and rapid reactive dyeing method, promising an effective dyeing process with excellent colour fastness.     

Synthesis and salt‐free dyeing characteristics of cationic reactive dyes containing polyetheramine segments

A series of cationic reactive dyes containing both quaternary ammonium and polyetheramine as soluble groups and monochlorotriazine as a reactive group have been synthesised and applied to cellulose fibre by salt‐free exhaust dyeing. Investigation of the synthesis method and dyeing properties of these cationic reactive dyes showed that the best pH value for these dyes is 6, and also that these cationic reactive dyes give a high substantivity to cellulose. In the salt‐free dyeing process, their adsorption was consistent with the Langmuir isotherm during the primary exhaustion stage, but in the secondary exhaustion stage the adsorption was in accordance with the Freundlich isotherm, and their secondary exhaustion reached up to 96% and above. Moreover, the degree of fixation, the levelling, and the transfer properties on cotton fabric were good. Light fastness reached grade 5–6, washing, perspiration, and dry rubbing fastness reached grade 4 and above, but wet rubbing fastness reached only grade 3–4.     

The effect of liposome on dyeing mohair/wool blends

The aim of this study was to examine the use of liposome in the dyeing of wool and mohair fibres with acid dyestuffs. Soybean lecithin and cholesterol were used to form the liposome membrane utilised in the dyebath. Liposome production was performed according to the thin lipid layer method (Bangham Method) using a rotary evaporator. Two different forms of liposome were used for dyeing wool and mohair fibres. In its first form, liposome was utilised as an auxiliary agent, where it was added to a conventional dyebath at the beginning of the process. In its second form, dyes were encapsulated with liposome and then used in dyeing. The effects of these two different forms of liposome were compared with conventional dyeing. Dyeing was carried out at depths of shade of 0.5%, 1.0% and 2.0% using three different concentrations of liposome (0.33%, 0.66% and 1.33%). An analysis of K/S values, fastness to washing, and the alkali solubility of fibres was conducted. The fibre samples dyed in the presence of liposome exhibited very good fastness to light (grade 8). The wash fastness test results of the liposomal‐dyed samples were significantly better (grade 4‐5) than for those samples which were conventionally dyed. In the presence of liposome, the tensile strength of fibres was 20 gf, whereas it was 11 gf without liposomes.     

Dyeing of poly(lactic acid) fibres with synthesised novel heterocyclic disazo disperse dyes

Poly(lactic acid) (PLA) is the first melt‐processable, renewable, sustainable and biodegradable natural‐based synthetic fibre. It has a broad range of uses and combines ecological advantages with outstanding performance in textiles. PLA fibre, as an aliphatic polyester, can be dyed with disperse dyes. Apart from the limited number of commercial disperse dyes, disperse dye exhaustion on PLA is generally lower than that on  poly(ethylene terephthalate) (PET). In this study, new heterocyclic disazo disperse dyes, substituted with methyl, nitro and chloro groups at their ortho‐, meta‐ and para‐ positions, synthesised in our previous study, were applied to PLA and PET fibres to examine their dyeing performance, and colour fastness and dye exhaustion properties. Different shades of yellow, orange, reddish brown and brown were obtained. Most of the synthesised novel heterocyclic disazo disperse dyes exhibited good build‐up properties with high K/S levels on both fibres. Para‐ bonding substituent provided higher K/S values than meta‐ and ortho‐ positions for –NO₂ and –Cl substituents for both fibres. Overall, the most synthesised novel heterocyclic disazo disperse dyes in this study exhibited good build‐up properties with high K/S, exhaustion and wet fastness levels on both PLA and PET fibres.      

Study of the Influence of Gemini Cationic Surfactants on the Dyeing and Fastness Properties of Polyester Fabrics Using Naphthalimide Dyes

In this paper, the dyeing and fastness properties of three monoazo naphthalimide dyes including different imide groups (dye 1: ethyl amine, dye 2: ethyl glycinate and dye 3: glycine) on a polyester fabric were investigated in the presence of two gemini cationic surfactants (symbolized as 12‐4‐12 or 14‐4‐14) and a conventional single chain surfactant, dodecyltrimethylammonium bromide (DTAB). The color strength (K/S) of naphthalimide dyes on polyester fabric was measured through the reflectance spectrophotometric method, and the values obtained in the presence of different cationic surfactants increased in the order of dye 3 < dye 2 < dye 1. Although the K/S values indicated that the gemini cationic surfactants had almost no effect on the dyeing behavior of dye 1, but they were effective in dyeing ability of dye 2 and dye 3. The data for dye 2 demonstrated that build up of polyester fabrics in the presence of gemini surfactants are more than the conventional cationic surfactant, and also K/S values of dye 3 on polyester fabrics were in the order: DTAB > 12‐4‐12 > 14‐4‐14. It was found that the washing and rubbing fastness properties improved with increasing the concentration of surfactants. In addition, the sublimation fastness of dye 3 was more than the other dyes owing to the presence of a polar group in its chemical structure, and the light fastness of naphthalimide dyes on polyester fabrics was generally moderate.     

Enhancing the wash fastness of disperse dyes on wool with oxidants

Disperse dyes are not currently applied to wool commercially, in large part because of inadequate wash fastness, but they do have potential, especially for wool‐polyester blends. In this study, for the first time hydrogen peroxide was investigated to increase the wash fastness of disperse dyes on wool. In the absence of oxidants, 10 disperse dyes from seven classes imparted colours with a range of depths (K/S 2‐26) with wash fastness (grey scale ratings for colour change) grades of 3 to 4‐5. Hydrogen peroxide had only small effects on colours and gave only small enhancements to wash fastness, which were limited to anthraquinone, nitrodiphenylamine, disazo and coumarin dyes. The bleach activators Prestogen W and citric acid enhanced the bleaching effect of hydrogen peroxide but did not assist with raising wash fastness. Hydrogen peroxide in post‐dyeing scouring made the dyeings brighter but did not significantly enhance wash fastness. Ammonium persulphate, which was included for benchmarking with earlier studies, yellowed the wool and decomposed some dyes. This study extends the range of dye classes whose wash fastness on wool can be improved by ammonium persulphate to now include diazo, coumarin and methine, and confirms that oxidants/free radical initiators have potential for enabling the disperse dyeing of wool.