Diffusion of dye mixtures in nylon 6. Binary mixtures of disperse dyes

The diffusion of binary dye mixtures of markedly different chemical constitutions (4-nitro-4′-aminoazobenzene and 1-amino-4-hydroxyanthraquinone) and of similar ones (1-amino-4-hydroxyanthraquinone and 1,4-dihydroxyanthraquinone) into nylon 6 film was examined. Apparent diffusion coefficients of dyes in the mixture within a single dyeing were determined by the film roll method at 60°, 70°, 80°, and 90°C. Diffusion coefficients of individual dyes used in a mixture of chemically dissimilar dyes are found to change little in comparison with single dyeings, while diffusion coefficients of dyes of similar structures are decreased appreciably. It is suggested that the latter effect is due to the interaction between two dyes in the fiber substrate.     

Assessing the compatibility of disperse dye mixtures by the use of colour coordinates

Polyester fabric was dyed with a mixture of three disperse dyes of similar hues (all in the red-yellow sector of colour space) in equal proportions at different depths. The colours of the dyed samples were measured on a spectrophotometer attached to an IBM Personal Computer and the results used to study the compatibility of the dyes in mixture. The dyes showed better compatibility at the lowest applied depths of 1.5% o.w.f. The technique based on K/S values was found to be useful for a practical dyer to judge the compatibility of dyes of similar hues in mixtures.     

Improving the compatibility of disperse dye mixtures using levelling agent — assessment through colour coordinates

The addition of a nonionic levelling agent to a dyebath containing a mixture of three disperse dyes in equal proportions and having similar hues (all in the red—yellow sector of colour space) significantly improved their compatibility, especially at higher applied depths of 3.0% and 4.5%. The dyed samples were measured for the differences in their colour coordinates with respect to the undyed substrate on a spectrophotometer attached to an IBM personal computer. The plots of ΔL* vs ΔC*_ab, ΔL* vs K/S, Δb* vs Δa*, Δa* vs K/S and Δ6* vs K/S clearly indicated the improvement in compatibility of the dye mixture.     

Synthesis and dyeing properties of novel disperse dyes. Part 2: Pyrazole disperse dye derivatives

Several new disperse dyes derived from thiosemicarbazides and acetoacetanilide have been synthesised. The dye structures were ascertained by chemical analysis and infrared measurements. Prepared dyes were used for dyeing nylon fabric by the exhaustion method. The colour strengths and dye fixation on the fabric were also determined. The results suggest a practical significance.     

The dyeing and colour characteristics of alkali–treated polyester fibres dyed with disperse dyes

Alkali–treated and untreated polyester fabrics were dyed for up to 6 h at 100°C with a series of six disperse dyes of different chemical structures. The alkali–treated polyester samples adsorbed more dye and were dyed to deeper depths of shade and slightly different shades than was the untreated polyester. The greatest differences were observed for the alkali–treated polyester with the most outer surface or skin removed. Dye structure and molecular size also affected the amount of dye adsorbed on the fibres, but did not delineate the nature of differences between skin and core morphology. This study shows that significant differences exist between the molecular structure of the skin and core of melt–spun polyester fibres.     

Relationship between the solubility of disperse dyes and the equilibrium dye adsorption in supercritical fluid dyeing

In order to understand the dyeing behaviour of synthetic fibres in supercritical carbon dioxide, the solubility of some disperse dyes in supercritical fluid, as well as the rate of dyeing and the equilibrium adsorption of these dyes, have been studied. Dye solubility was measured by a dynamic analytic method at a range of pressure (7.5–25 MPa) and temperature (50–145 °C). The apparent rate of dyeing was measured and the dyeing isotherm was obtained by plotting the equilibrium dye adsorption against the equilibrium dyebath concentration. Linear isotherms were obtained when poly(ethylene terephthalate) samples were dyed with the disperse dyes. The mechanism of dyeing using supercritical carbon dioxide was discussed by considering the solubility, the dyeing rate and the dyeing isotherm.     

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.     

Diffusion of disperse dyes into super-microfibres

The disperse dyeing process for polyester fibres is complex. It is characterised by the diffusion-controlled sorption of dyes and depends on dye concentration, dyebath temperature, dye liquor flow rate and fibre count. Moreover, the dyeing properties of super-microfibres are also quite different from those of microfibres or conventional polyester fibres. In this paper the influence of dyebath temperature, initial dye concentration and fibre count on the diffusion coefficient and the sorption isotherms has been studied. The analysis of kinetic properties has been restricted to infinite dyebath conditions. All experimental results have been compared terms of fibre count and dyebath temperature.     

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.     

Adsorption isotherm of a disperse dye

An absorption isotherm equation similar in form to Langmuir’s equation was obtained for monomolecular adsorption of a dye on the inner surface of a fibre for the process of dissolution of a dye in amorphous regions of a fibre using the assumptions concerning formation of dye—macromolecule fragment solvates in the ratio of 1:1. Linearity of the function 1/C_F = f(1/C_S) is possible both in adsorption of the dye with formation of a monomolecular layer (Langmuir) and in dissolution of the dye in the amorphous part of the fibre-forming polymer with formation of solvates. __________ Translated from Khimicheskie Volokna, No. 2, pp. 61–63, March–April, 2006.     

Polymeric dye receptors for disperse dyeable polypropylene fibers

Polypropylene fibers containing various amounts and different types of 2-vinyl pyridine/styrene (2VP/St) copolymer in terms of molecular weight and molar ratio were prepared, and the disperse dyeability of these fibers were investigated. In addition, the disperse dyeability of 2VP/St copolymer alone was also studied. © 1992 John Wiley & Sons, Inc.     

分散染料防尘油的研制和应用

以矿物油和自合成的乳化剂为主要原料研制成分散染料防尘油,并对其应用性能进行了测试。该产品的各项应用性能完全达到了进口同类产品的质量指标,并在一定程度上使分散染料的高温分散性得到改善。     

Improved compatibility of disperse dye mixtures using levelling agent—assessment through hue angle measurement

The compatibility of a mixture of disperse dyes in equal proportions having similar hues (all in the red-yellow quadrant of the colour space) has been assessed at different applied depths on polyester fabric, with and without levelling agent, using plots of hue angle against KIS values. The plots were found to be useful in indicating the improvement in the compatibility of dyes at higher applied depths attributable to the addition of a nonionic levelling agent.     

Pyrimidyl and imidazolyl coumarin disperse dyes

The synthesis of 7-diethylaminocoumarin derivatives containing pyrimidine and imidazole substituents at the 3-position is described. These have been evaluated as disperse dyes on polyester.     

Dyeability of polyurethane nanofibres with disperse dyes

Nanofibres enjoy broad technical applications in filtration, medical, biosensing, functional, and high‐performance textiles. Recent trends/developments in nanofibre research have also focused on the coloration of nanofibres. In this context, polyurethane nanofibre webs, which have been commercially successful, were electrospun and dyed with a high‐energy‐level CI Disperse Red 167:1 dye and a low‐energy‐level CI Disperse Blue 56 dye by the pad‐dry‐cure method. The dyed polyurethane nanofibres exhibited good colour strength values with acceptable colour fastness. Results revealed that the high‐energy‐level dye produced slightly better colour strength than the lower‐energy‐level dye. Further, scanning electron microscopy images showed that the morphologies of dyed and undyed nanofibres were almost identical.     

Redispersibility of disperse dyes containing polymeric dispersants

Dispersing agents are used during the manufacture of disperse dyes to ensure standard dyeing properties. Polymeric dispersing agents have advantages over classical dispersants in that they are are colourless and easily degraded and do not have to be present in such large quantities. Redispersibility is a potential problem and we have therefore investigated the redispersibility of CI Disperse Red 60 (pure colorant) achieved with classical and polymeric dispersants. We have developed a calculation procedure that will provide some basis characteristics of the studied system and make it possible to choose the composition of mixture of components used for preparation of disperse dye at which the relative coefficient of redispersibility (K_r) is optimised. We found that the K_rof dye prepared with classical dispersants was 10–40 while that of dye prepared with polymeric dispersant was 0.05–7.0.     

Studies in the aggregation of disperse dyes

The aggregation of disperse dyes in aqueous solution along with surfactants has been studied spectrophotometrically by Klotz's method and polarographically employing llkovic's equation by diffusion coefficient method. The extent of complex formation between dye and surfactants have been studied and compared with the determination of aggregation numbers from polarographic measurements.     

Synthesis of some new disperse anthraquinone dyes

1-Hydroxy and/or 1-aminoanthraquinone was allowed to react with formaldehyde in an alkaline medium to give 1-hydroxy or 1-amino-2-hydroxymethyl-9,10-dihydroxy-anthracenes, which gave on air oxidation, hydroxymethylanthraquinone derivatives (I). Interaction of 1-amino-2-hydroxymethylanthraquinone or its 4-bromo derivative with carbonyl compounds in the presence of an acid catalyst gave (1,3)oxazine derivatives (II). The methylene group in position-2 of the (1,3)oxazine ring was found to be highly reactive and reacted with carbonyl compounds to form the corresponding arylidenes (III). Selective oxidation of dimethyl oxazine derivatives with SeO₂ gave the corresponding dialdehyde (IV), which interacted with aromatic amines to give the corresponding Schiff bases (V). The bromine atom in the 6-position of II was easily replaced by aromatic amines to give blue disperse dyes (VI).     

One-bath dyeing of wool/polyester blends with acid and disperse dyes. Part 2 — disperse dye distribution on polyester and wool

Disperse dye distribution on polyester and wool during one-bath dyeing of wool/polyester blends is discussed. The addition of carriers increases the wool's intrinsic saturation value for disperse dye, thus raising the degree of staining on the wool component at the low dye uptakes. However, staining can be minimised if the dyeing is close to or attains equilibrium conditions. Sequestering agents can accelerate the disperse dye diffusion out of the wool fibre, further reducing staining on wool and transferring more disperse dyes from wool to polyester. Citric acid can be used as a sequestering agent as well as a pH adjusting agent.     

Evaluation of colour fastness and thermal migration in softened polylactic acid fabrics dyed with disperse dyes of differing hydrophobicity

This paper addresses the relative effects of softeners having different properties and their method of application (exhaust vs pad) on the colour fastness of poly(lactic acid) fabrics dyed with a range of disperse dyes with different levels of hydrophobicity. A comparison was made with a correspondingly finished polyethylene terephthalate fabric. Possible relationships between the levels of hydrophilicity/hydrophobicity of the dye, and softener, and the colour fastness were explored. Finally, the amount of dye thermally migrated into the finish on the softened poly(lactic acid) and polyethylene terephthalate fabrics was examined in comparison with their colour fastness. Softened poly(lactic acid) fabrics dyed with CI Disperse Red 167.1 exhibited more thermal migration, and hence lower colour fastness, than the corresponding polyethylene terephthalate fabrics. Conversely, softened poly(lactic acid) fabrics dyed with Dianix Deep Red SF exhibited less thermal migration, and hence better colour fastness, than the corresponding polyethylene terephthalate fabrics. Overall, no clear relationship was found between the hydrophobic nature of the disperse dye and the hydrophobic character of the softener on the colour fastness.