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.     

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.     

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.     

One‐bath dyeing of polyester/cotton blends with disperse and bis‐3‐carboxypyridinium‐s‐triazine reactive dyes. Part 2: Application of substantive reactive dyes to cotton at 130 °C and neutral pH†

An earlier paper reported that the reactive dyes (not the disperse dyes) were responsible for the inability to achieve heavy depths of shade, when dyeing polyester/cotton blends by a one‐bath process at 130 °C and neutral pH using reactive dyes containing a 3‐carboxypyridinium‐s‐triazinyl group. It was shown that the poor colour yield of the bis‐3‐carboxypyridinium‐s‐triazine reactive dyes was because of their low exhaustion level at 130 °C and pH of 7.0–7.5. We now report the synthesis and evaluation of some bis‐3‐carboxypyridinium‐s‐triazine reactive dye structures, possessing highly substantive chromophores, as a means of obtaining high colour yield, on 100% unmercerised cotton, under the specified dyeing conditions. The technical performance of these dyes under such conditions was compared with that of selected Novacron (Cibacron) LS and Procion H‐E dyes, applied under their recommended (atmospheric) dyeing conditions.     

Preparation and properties of water‐soluble polyester surfactants. II. Preparation and surface activity of silicone‐modified polyester surfactants

We prepared a novel series of water‐soluble silicone‐modified polyesters [poly(ethylene glycol) (PEG)–silicone polyesters] by reacting organopolysiloxane with a hydroxy‐terminated polyester. The polyesters were obtained by the polymerization of maleic anhydride and PEGs (molecular weights = 2000, 4000, 6000, 8000, and 10000). These water‐soluble PEG–silicone polyesters can be used as auxiliaries in dyeing process because they exhibit good surface activities such as surface tension, low foaming, and wetting power. The presence of these surfactants also retarded the rate of nylon dyeing with acid dyes. The retarding effect and low‐foaming property of these novel PEG–silicone polyesters make it possible for these surfactants to be used as leveling agents for modern nylon dyeing with acid dyes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3005–3012, 2002     

Synthesis and characterisation of benzothiazole‐based solid‐state fluorescent azo dyes

Novel solid‐state fluorescent azo dyes containing a 2‐[4‐(dimethylamino)phenyl]benzo[d]thiazol‐6‐amine as the electron donor group were synthesised. These dyes showed a molar extinction coefficient in the range of 20 000–30 000 l/mol/cm. These compounds were characterised by strong solid‐state fluorescence under long ultraviolet light (365 nm). Absorption and fluorescence spectra revealed that electron coupling originating from broad π‐electron delocalisation and the keto–enol form is responsible for the large Stokes shift. These dyes were readily soluble in common solvents such as dichloromethane, chloroform, dimethyl formamide , tetrahydrofuran and dimethyl sulphoxide and were characterised by means of elemental analysis, proton nuclear magnetic resonance and mass spectrometry. Thermogravimetric analysis of solid‐state fluorescent dyes show thermal stability up to 270 °C and can therefore be used for polymer application. The coloristic properties of these dyes were evaluated on polyester by the disperse dyeing method.     

Synthesis and properties of novel aziridinyl azo dyes from 2-aminothiophenes—Part 2: Application of some disperse dyes to polyester fibres

A series of yellow to greenish-blue aziridinyl azo dyes and their azo precursors containing a thienyl coupling moiety has been applied to conventional polyester fibre as well as microdenier polyester by high temperature exhaust dyeing. Heat transferability of these dyes onto polyester fibre has also been examined, using conventional heat-transfer printing techniques. The relevant dyeing characteristics, heat transferability, build-up, dyeability on microfibre polyester, washfastness and lightfastness are given. These aziridinyl dyes are reactive to polyester fibres under HT dyeing conditions. Fabrics dyed with aziridinyl dyes are more resistant to solvent extraction than those dyed with conventional dyes. Residual liquors showed only a pale colour when fabric dyed with aziridinyl dyes was dissolved and then precipitated, whereas a coloured polyester precipitate was obtained.     

Synthesis and application of yellow azo‐anthraquinone disperse dyes for polylactide fibres

1‐Phenyl‐3‐methyl‐5‐pyrazolonyl azo‐anthraquinone dyes having high light fastness on polylactide fibres were synthesised from 1‐aminoanthraquinone via a diazotisation‐coupling reaction with 1‐phenyl‐3‐methyl‐5‐pyrazolones. The structures of these new dyes were confirmed using mass spectrometry, infrared and proton nuclear magnetic resonance spectroscopy and combustion analyses. Their dyeing behaviour on polylactide fibres was also determined, whereupon it was found that the title dyes could be applied at a relatively low dyeing temperature and that the corresponding dyed fabrics had good fastness properties.     

Use of β‐cyclodextrin in the dyeing of polyester with low environmental impact

In this paper, the effect of β‐cyclodextrin as an additive in the dyeing of polyester with disperse dyes, as a substitute for a commercial surfactant commonly used, was explored with the aim of reducing the environmental impact of the exhausted baths. Using a chemometric approach, a small group of dyes was selected as a ‘training set’ to be representative of a larger series of dyes with a similar structure. The selected dyes were synthesised and applied to the dyeing of polyester fibres under various conditions. The technological properties of the dyed samples were measured. The results showed that β‐cyclodextrin can satisfactorarily be used as an additive in dyebaths for polyester without the addition of other auxiliaries, with a positive environmental impact. Solubility isotherms evidenced dye–β‐cyclodextrin interactions. The formation of inclusion complexes did not produce negative effects on the dyeing performance. Light fastness values were modelled as a function of the structure by the chemometric partial least squares method and the established model was used to predict the fastness of dyes of analogous structure, not yet explored.     

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.     

A facile synthesis and tautomeric structure of novel 4‐arylhydrazono‐3‐(2‐hydroxyphenyl)‐2‐pyrazolin‐5‐ones and their application as disperse dyes

The main target of this paper was the synthesis of novel azo disperse dyes with better dyeing properties, together with a systematic investigation to determine their dominant tautomer(s) from 12 possible tautomeric structures. In this regard, novel azopyrazolin‐5‐one dyes were synthesised via the reaction of hydrazine hydrate with 2,3,4‐chromantrione‐3‐arylhydrazones. The acid dissociation constants both in the ground and in the excited state for the series prepared were determined and correlated by the Hammett equation. The results of this correlation, together with spectral data, indicated that the compounds under scrutiny exist predominantly in the keto‐hydrazo structure as a Z‐configuration, both in the ground and in the excited state. Finally, the synthesised dyes were applied as disperse dyes for dyeing polyester fabrics, and their fastness properties were evaluated. Also, the position of colour in CIELAB coordinates was estimated and discussed.     

Synthesis,spectral properties and application of novel disazo disperse dyes derived from polyester waste

Terephthalic dihydrazide was obtained through aminolytic depolymerisation of polyester bottle waste by using hydrazine hydrate. It was further reacted with 4‐aminobenzoic acid in the presence of polyphosphoric acid to obtain a cyclic compound, 4,4′‐[5,5′‐(1,4)‐phenylene)bis(1,3,4‐oxadiazole‐5,2‐diyl)dianiline, having a heterocyclic moiety. Diazotisation of this compound followed by coupling with various N,N‐disubstituted anilines afford a series of novel disazo disperse dyes. The structures of these synthesised dyes were confirmed by elemental analysis and Fourier Transform–infrared, proton nuclear magnetic resonance and mass spectroscopy. Ultraviolet–visible spectra of these azo dyes in different polar solvents showed considerable variation in the wavelength of maximum absorbance (λ_max). Application of these dyes on polyester and nylon fabrics using high‐temperature dyeing methods gave brilliant yellowish red hues with fair to moderate light fastness and very good to excellent wash fastness and sublimation fastness.     

Substituent Effects on the Colour,Dyeing and Fastness Properties of Trisubstituted 4–N–β–Hydroxyethyl–N–β–Cyanoethylaminoazobenzenes

School of Chemistry and Chemical Technology University of Bradford Bradford West Yorkshire BD7 1DP The synthesis of a series of 2′, 4′, 6′-trisubstituted derivatives of 4–N–β–hydroxyethyl–4– N–β–cyanoeth ylaminoazobenzene is reported, and the effect of the nature of the substituents on the colour, dyeing and fastness properties of these dyes is described. The dyes coloured synthetic–polymer fibres well, with the exception of those containing a methylsulphonyl group, which gave weaker dyeings on polyester. Dyes substituted by 2′-nitro groups tended to have poor light fastness, and reasons for the variations in the light fastness of monoazo dyes of this type are discussed.     

One‐bath union dyeing of wool/polytrimethylene terephthalate blends†

The one‐bath dyeing of blends of polytrimethylene terephthalate (PTT) staple and wool has been investigated. The exhaustion of selected Terasil disperse dyes on PTT fibre and Lanasol reactive dyes on wool was measured as a function of temperature, together with the cross‐staining of the Terasil dyes on the wool component and the Lanasol dyes on PTT component. Most Terasil disperse dyes achieved satisfactory dye uptake on PTT at 110 °C, whereas on conventional polyester (polyethylene terephthalate) temperatures of up to 130 °C are required. An optimised union‐dyeing technique for wool/PTT blends was developed which minimised the staining of Terasil disperse dyes on wool and produced dyed goods with high levels of wet colour fastness. Carriers were not required to enhance the dyeability of PTT at low temperatures. The wool component appeared to be protected against damage at 110 °C by the reactive dyes. The results indicate the potential for blending PTT fibre and wool to produce fabrics that are easier to dye at lower temperatures than conventional wool/polyester blends.     

The Dyeing Properties of Monoazo Reactive Disperse Dyes Derived from –Chloro–4–aminoacetophonone on Polyester Fibre Blends

The preparation of monoazo reactive disperse dyes from –chloro–4–aminoacetophenone and the dyeing properties of these dyes on polyester–cotton and polyester–wool blends are reported.     

Kinetics of thermo-fixation of solvent dyes and pigments in polyester fibres

The diffusion coefficient of a dye in fibres is critical to understanding the dyeing process and coloration quality of products. In this paper, the diffusion kinetics of solvent dyes in the thermosol dyeing of polyester fibres was studied by measuring K / S of the dyed polyester fabrics based on the Kubelka–Munk equation. The diffusion coefficients of two model solvent dyes were estimated with Hill's equation using the experimentally measured K / S values and were found to be in good agreement with those calculated from the traditional extraction method. Such a measurement method was applied to several other solvent dyes and pigments that have different molecular sizes and a good correlation between the measured diffusion coefficients and sizes of these dyes and pigments was found. The results indicate that it is feasible to use K / S measurement of dyed fabrics and Hill's equation to evaluate the kinetics of the thermosol dyeing process under certain conditions.     

Antimicrobial activity of some new 4‐arylazo‐3‐methylthiophene disperse dyes on polyester fabrics

A series of novel 4‐arylazo‐3‐methylthiophenes was synthesized by the heterocyclization of 2‐arylhydrazono‐2‐acetyl thioacetanilide derivatives with a variety of α‐halogenated reagents, such as chloroacetone, phenacyl bromide, ethyl chloroacetate, and chloroacetonitrile. The structures of the synthesized thiophene derivatives were confirmed by ultraviolet–visible, IR, and ¹H‐NMR spectroscopic techniques and elemental analysis. The synthesized dyes were applied to polyester fabrics as disperse dyes, and their fastness properties were evaluated. The dyed polyester fabrics displayed antibacterial efficacy against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Exhaust dyeing of polyester‐based textiles using high‐temperature–alkaline conditions

The factors affecting the dyeability of polyester‐based textiles with disperse dyes in an alkaline medium were studied. It was found, for a given set of dyeing conditions, that (a) the appropriate conditions for attaining a higher color yield were 45 min at 130°C with pH 9 using a material‐to‐liquor ratio of 1/10; (b) increasing the Diaserver® AD‐95 concentration to 2% ows (based on weight of substrate) as well as including triethanolamine to 2% ows in the dyeing formulations bring about a significant improvement in the dye uptake; (c) both a preheat setting from 160 to 200°C/30 s and an alkaline weight reduction have a positive impact on postdyeing with the used disperse dye; (d) the extent of dye uptake as well as the color strength are governed by the type of substrate, that is, knitted fabric > spun yarn > woven fabric, nature of the dye stabilizer, that is, EDTA > Diaserver® AD‐95 > Tinoclorite® CBB > citric acid > none, as well as kind of the disperse dye; (e) direct reuse of the disperse dyebaths, without reconstitution, in the dyeing of the used substrates was shown to be feasible in a single shade and in the reverse‐order dyeings (dark → light); (f) one‐bath, one‐step exhaust dyeing of polyester/cotton‐knitted fabric using selected disperse reactive dyes combinations under high‐temperature alkaline conditions is feasible; and (g) the color and fastness properties of the resultant dyeings depend on the type of the used auxiliaries, in addition to the nature of disperse/reactive dyes combinations as well as compatibility with other ingredients. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3563–3573, 2003     

Azo disperse dyes for synthetic fibres. 3: 2-Styrylquinazolone derivatives

Fifteen variously substituted derivatives ( IVa–o ) of 2-styrylquinazolone have been prepared for use as dye-stuffs. The effects of the nature and orientation of substituents on the colour and dyeing properties of these dyes on polyester and acrylic fibres were assessed.     

Neutral dyeing of wool and wool/polyester blend fabrics using sulphatoethylsulphone reactive‐disperse dyes

Two models of temporarily anionic sulphatoethylsulphone reactive disperse dyes were applied to wool, polyester and wool/polyester blend fabrics at different dyeing pH. Maximum exhaustion values and colour yield were observed at pH 7. The results showed that reactive disperse dyes containing bis‐sulphatoethylsulphone reactive groups were more convenient for neutral dyeing of wool and wool/polyester blend fabrics if compared with a dye containing a mono‐sulphatoethylsulphone group. Excellent to very good wet fastness properties on all dyed fabrics were achieved.