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.

A series of azo disperse dyes was synthesised and the purified, synthesised dyes were characterised by proton nuclear magnetic resonance, thin-layer chromatography and melting point measurement. The spectroscopic properties of the dyes in solution were studied by dissolving the dyes in ethyl acetate and methyl benzoate. These were seen as mimicking the environment of the dye when inside dyed poly(lactic acid) and poly(ethylene terephthalate), respectively. Reflectance spectra of the dyes on both polyester substrates were also measured in order to correlate with the spectroscopic properties of the dyes in solution. The absorbance spectra of the dyes in solution exhibited a hypsochromic (lower wavelength of maximum exhaustion) shift when dissolved in ethyl acetate, compared with methyl benzoate. The occurrence of this yellow shift was attributed to the lower polarity of ethyl acetate compared with methyl benzoate. The colour of the dyes in ethyl acetate solution was also brighter and stronger (higher molar extinction coefficients) than that in methyl benzoate. Most of the synthesised dyes exhibited high levels of exhaustion onto the two polyester fabrics. However, the visual colour yields, for those dyes having approximately the same high level of exhaustion, were different, the dyed poly(lactic acid) being stronger (higher K/S value) as well as being yellower and a trace brighter than the dyed poly(ethylene terephthalate). This difference correlated well with the solvatochromic study of the dyes in ethyl acetate and methyl benzoate solution.

Water droplets falling onto finished fabrics can create spots which can spoil the appearance of the fabric. This study compares the propensity of softened filament polylactic acid and polyester fabrics to exhibit the adverse affects of ‘water-spotting’, and to identify suitable softeners and methods for their application to minimise and eliminate the problem. The degree of water spotting was greater on softened polylactic acid fabrics than on softened polyester fabrics. Polylactic acid and polyester fabrics with hydrophobic properties did not exhibit any water spotting. Softeners applied by an exhaustion process resulted in a finished fabric which exhibited no water spotting for either dyed polylactic acid or dyed polyester fabrics. The softening active agent was not responsible for the water spotting. The other components in the softener formulation (such as emulsifier, wetting agent), which carries the unfixed dyes with water, were found to be responsible. The water spot halo disappeared after a single machine laundering process.

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 Cl 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.

We have studied the potential degradation of poly(lactic acid)-based fabrics treated with commercial softeners and stored under two sets of conditions for one year. Initial wet-processing caused a fall in molecular weight of about 28%, irrespective of after-treatment. Storage at 40 degrees C and 80% RH produced further degradation which, with few exceptions, was aggravated by the presence of softeners. Ultimately, all samples degraded beyond the point of commercial usefulness. No clear distinction could be made between the effects of softeners having differing compositions. In contrast, fabrics stored under milder conditions of 23 degrees C and 50% RH showed no significant time-dependent polymer degradation, irrespective of the treatment applied. There were slight changes in tensile properties and some evidence of physical structural effects having occurred, which we attribute to physical aging. However, we do not believe these to be so serious as to call into question the long-term viability of PLA-based textile products. (C) 2009 Elsevier Ltd. All rights reserved.

Three novel trisazo hetero bi-functional reactive dyes based on J-acid derivatives were prepared using the diazonium salt of [4-(4-sulphophenylazo-)-2,5-dimethylazobenzene-2-sulphonic acid] and a hetero bi-functional coupling component, derived from 1-hydroxy-6-aminonapthalene-3-sulphonic acid (J-acid), 1-hydroxy-6-methylaminonapthalene-3-suiplionic acid (methyl J-acid), and 1-hydroxy-6-aminonaphthalene-3,5-disulphonic acid (sulpho J-acid). On balance, the dye derived from sulpho J-acid displayed the most attractive set of technical properties, building up and fixing more efficiently than those derived from J-acid and methyl J-acid. In addition, the sulpho J-acid based dye offered better migration and, therefore, level dyeing and ease of wash off.

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.

One of the limitations of DyStar’s TTN one‐pass continuous dyeing process for dyeing polyester/unmercerised cotton blends with disperse and reactive dyes is its inability to achieve heavy depths economically and part 1 of this study indicated that the limitation could be attributed to the reactive dye [1]. In this study, the constituents of the pad liquor were varied to determine if the visual colour yield of selected reactive dyes could be improved. In so doing, it was possible to speculate whether the low colour yield from some of the reactive dyes used in the TTN process was as a result of inefficient ‘delivery’ of the dye to the reactive sites on the cotton.

Lyocell fabrics were treated with 2,4-diacrylbenzenesulfonic acid (DABS) crosslinking agent under wet and dry reaction conditions, and also for comparison with a conventional dimethyloldihydroxyethylene urea (DMDHEU) agent, reacted under dry conditions. All treatments with DABS led to an improvement in wet and also dry fabric abrasion resistance, measured using the Martindale test, whereas treatment with DMDHEU reduced dry abrasion resistance. A model based on the kinetic strength theory of Zhurkov was used to interpret results, where dry-state abrasion is reduced through stress concentration at the rigid DMDHEU crosslinks, which does not Occur with the larger flexible DABS crosslinks. Tensile testing of treated lyocell fabrics revealed that breaking strength initially increased at low levels of DABS fixation, but fell at similar levels of DMDHEU fixation. The effect with DABS is due to an increase in the effective molecular weight, which can outweigh the development of stress concentration due to crosslinking. The Zhurkov model was also used to interpret the wet-state abrasion resistance of lyocell fabrics. From this it is concluded that water swelling leads to an increase in stress concentration within fiber structure because of the loss of lateral interfibrillar connectivity, which is reestablished by both DMDHEU and DABS crosslinking. (C) 2009 Wiley Periodicals, Inc. I Appl Polym Sci 114:2116-2127,2009

In the continuous dyeing of polyester/cellulose blends, the trend over the last 20 years, towards shorter production runs and greater numbers of fashion shades, has led to the development of more productive processes, in particular, the use of a one-pass pad-dry-thermofix process for the application of disperse and reactive dyes. However, there are limitations to such a one-pass process, of which the most important is the limited colour depth that can be achieved on polyester/unmercerised cotton blends. The current study examines the reasons for this limitation, with a view to either modifying the dyeing process or designing superior dyes.

Linitest and washing machine results have been compared for the assessment of dye damage/colour fading. 14 dyes of the AISE Monitor Dye Set for bleach induced dye fading were applied in several multi-cycle washes in both devices. it has been shown that dye fading in both applications correlated well with bleach containing detergents, although often the absolute level of fading was higher in a washing machine. Both systems identified the same dyes as being either problematic or safe. On the other hand experiments without a bleach system revealed that dye fading in a washing machine could be different from that generated in a Linitest.

A new water‐soluble monomeric agent for the aminisation of lyocell has been designed and synthesised. The agent, which contains a sulphatoethylsulphonyl group, an s‐triazinyl keto–enol tautomeric system and a primary aromatic amine was prepared in acidic media, in good yield from cyanuric chloride, p‐aminophenyl‐β‐sulphatoethylsulphone and p‐phenylenediamine, via a triazinyl betaine intermediate.

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 degrees 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 degrees 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.

Four dichloro‐s‐triazinyl dyes and 2,4‐dichloro‐6‐p‐sulphoanilino‐1,3,5‐triazine have been applied by exhaustion methods to dried lyocell fibres. The method of application, of both dyes and agent, influenced the cross‐linking performance and, in turn, the wet abrasion resistance of the treated fibre. However, dyeing alone, with any of the MX dyes used in this study, was insufficient to protect the fibre from wet abrasion problems during laundering. A comparison between one of the MX dyes, Chloranyl Orange MX‐2R, and 2,4‐dichloro‐6‐p‐sulphoanilino‐1,3,5‐triazine on a mol‐for‐mol fixed basis, showed 2,4‐dichloro‐6‐p‐sulphoanilino‐1,3,5‐triazine to be greatly superior at protecting lyocell against wet abrasion.

Application of 4,6‐(p‐β‐sulphatoethylsulphonyl)‐anilino‐1,3,5‐triazin‐2(1H)‐one (Hydroxy‐XLC) to lyocell fibre produced two types of crosslinking, one essentially permanent and the other transitory, in the presence of weak alkali. Permanent or stable crosslinking arose from covalent bonding between the fibre and vinyl sulphone reactive groups. The transitory or unstable crosslinking was due to two agent molecules forming an intermolecular ether linkage, followed by crosslinking via the residual vinyl sulphone reactive groups. On subsequent mild alkali treatment, the ether bond was cleaved, resulting in a loss of wet abrasion resistance (Nass–Scheuer–Festigkeit, NSF), without any significant loss of agent from the fibre. Further treatment with mild alkali partially restored the NSF value. The formation of ethers is a general reaction of vinyl sulphones in alkaline medium, and for Hydroxy‐XLC, this side reaction exerts a negative influence on the compound's suitability as a crosslinking agent.

An exhaust application method for 4,6‐(p‐β‐sulphatoethylsulphonyl)anilino‐1,3,5‐triazin‐2(1H)‐one to dried lyocell fibre has been developed. The procedure employs a temperature gradient technique with all of the salt and alkali present at the start. This method gives consistent wet abrasion resistance values with a standard deviation only marginally inferior to Tencel A100. Subsequent dyeing of lyocell fibres, in turn with two reactive dyes, gave build‐up profiles indistinguishable from untreated fibre. The lyocell–agent bonding was stable to high temperature polyester dyeing conditions at pH 6, but unexpectedly showed some instability (as evidenced by a fall in wet abrasion resistance values) when subjected to base‐catalysed reactive dyeing conditions.

The total water capacity of a series of never-dried and re-wetted cellulosic fibres has been shown to correlate with the accessible volume described by a thermodynamic model. The model was applied to interpret the adsorption behaviour of a range of reactive dyes in electrolyte solutions and was successful in accounting for differences in fibre anionic charge. Comparative solute exclusion data indicated the existence of a population of very small spaces in never-dried cellulosic fibres, which may be associated with water disrupting the cellulose \({1\overline{1}0}\) crystal planes. Such intra-crystalline spaces may provide sites for uptake of planar substantive dyes and may also be accessible to sodium ions. The study showed that never-dried lyocell undergoes a large reduction in total wet capacity following initial drying, which is believed to be due to both exudation of crystal water and to inter-fibrillar crystallisation. This crystallisation mechanism may not be so effective for viscose and modal, which have poorer structural organization. Re-wetted lyocell exhibits high dye adsorption, which may result from the development of a uniform fibrillar morphology with a high surface area. This structural aspect is not expressed by the thermodynamic model.

Over the last 20 years, selected disperse dyes and bis-3-carboxypyridinium-s-triazine reactive dyes have been widely promoted for the exhaust dyeing of polyester/cotton blends in a one-bath-one-stage ('all-in') process under neutral conditions. However, despite the time and energy savings afforded by this elegant dyeing process, there is a belief in the dyeing industry that economical production is limited to pale and medium depths of shade. In this paper, the two dye classes (disperse dyes on polyester and bis-3-carboxypyridinium-s-triazine reactive dyes on cotton) have been investigated to understand why heavy depths of shade cannot readily be obtained economically using this process.