Studies in dyeing. II. Effect of crystal modification of disperse dyes on polyester dyeing at 130°C

Four commercial disperse dyes were purified and their different crystal forms were prepared by crystallizing from different solvents or precipitating from their solutions in glacial acetic acid by dilution with water. These forms were found to have different melting points. They were dyed on polyester fibers at 130°C to fiber saturation values by changing the dyebath every 15 min. The effect of pretreatment of the dyes in an aqueous environment at different temperatures (60°, 100°, and 130°C) for 15–60 min in the presence and absence of a dispersing agent on the dye uptake values was also studied. Such treatments are shown to reduce the dye uptake. The implication of these treatments in practical dyeing are pointed out.     

The effect of dyes and dyeing on the mechanical properties of polymeric materials

The effect of reactive and disperse dyes and dyeing on the mechanical properties of cotton and polyester fibers, respectively, has been studied. It is observed that reactive dye (Procion Brilliant Red MX-2B) and disperse dye (Dispersol Red B-2B) caused a decrease in the tensile strength of the fiber which was often accompained by a decrease in the extensibility and general improvement in the tensile stiffness of the fibers. A linear relationship exists between percent disperse dye on the fiber and the square root of time of dyeing for poly(ethylene terephthalate) fibers in the initial region of dye uptake.     

The solubility parameter concept applied to disperse dyeing of polymers

The solubility parameter concept offers a logical link between the theory of solutions and of nonionic (disperse) dyeing. An attempt has been made to apply the concept to correlate the solubility of several disperse dyes in secondary cellulose acetate, cellulose triacetate, and polypropylene with the calculated solubility parameters of both the polymers and the dyes. When the dyes are applied on hydrophilic polymers from an aqueous dispersion, the correlation between the solubility parameter concept and the dye solubility is not close. One of the reasons for this may be the fact that dyeing of the fibers is, in fact, not a solution in the dry fibers, but consists essentially either in displacement of water molecules from the water swollen fibers and/or, perhaps, in additional swelling by the dye. Consideration of this fact and also correcting for the contribution of hydrogen bonding and dipole interactions to the cohesive energy density brings the disperse dye solubility data into a better agreement with the concept. The concept should be applicable without complications to the dyeing of nonpreswollen fibers, such as polypropylene from aqueous dispersion, or any fiber by the Thermosol process and particularly to dyeing from the vapor phase. The few data available appear to support this view.     

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.     

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.     

Alkaline dyeing of polyester and polyester/cotton blend fabrics using sodium edetate

An alkaline dyeing of polyester with an alkali‐stable disperse dye, Dianix® Scarlet AD‐RG, was developed using sodium edetate as an alkaline buffering agent. The results obtained indicate the suitability of using sodium edetate for alkaline dyeing of polyester when compared with the control alkaline dyeing using Dianix AD system. Selected mono and bifunctional reactive dyes were used in combination with the alkali‐stable disperse dye for dyeing of polyester/cotton blend. Different dyeing methods for cotton and polyester/cotton blend fabrics using sodium edetate were evaluated in comparison with their respective control alkaline dyeing methods. The results of using sodium edetate in one‐bath two‐stage and two‐bath dyeing of polyester/cotton blend were comparable with that of the control dyeing method. Particularly, no change in the leveling and fastness properties was evaluated for all samples irrespective of the dyeing method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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     

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.     

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.     

Disperse dyeing of polyester fibers: Kinetic and equilibrium study

The effect of temperature on the dyeing rate constant k, diffusion coefficient D, and time of half‐dyeing t_1/2 was evaluated for the dyeing of polyester fibers with two disperse dyes, an azo and an anthraquinone dye. Activation energies of diffusion E were calculated. The polyester dyeing equilibrium was also studied and the partition coefficient K and standard affinity Δμ° at various temperatures were determined for the anthraquinone dye. Standard enthalpy ΔH° and standard entropy ΔS° of dyeing were also obtained. The same equilibrium parameters were not obtained for the azo dye because of its dyeing behavior. A similar kinetic and equilibrium study was made for the pure azo and anthraquinone compounds free from the dispersing agents present in the commercial dyes and the results are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 123–128, 2002     

Improved mechanism of polyester dyeing with disperse dyes in finite dyebath

A new sorption mechanism of polyester dyeing with disperse dyes in water is proposed. It is considered dye aggregates could not be sorbed unless they turn into single molecules. However, this theory could not explain numerous sorption phenomena: sorption continues when equilibrium dye concentration exceeds its solubility; dyeing at long liquor ratio, using microencapsulated or crystal‐modified dyes do not change concentration of single dye molecules or dye solubility, but increase sorption rate and quantity in a fixed time. We demonstrate that both single and aggregated dye molecules could be sorbed using CI Disperse Blue 56. Because of the large size and low diffusion rate, dye aggregates could temporarily block sorption channel and prevent entry of other dyes. Therefore, only using extra more dyes could get a dark colour. Series of approaches could be proposed to reduce or eliminate the sorption problems caused by aggregates using the new sorption mechanism.     

One-bath dyeing of polyester/cotton with disperse and bis-3-carboxypyridinium-s-triazine reactive dyes. Part 1: Factors limiting production of heavy shades

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.     

The carrier dyeing of synthetic fibers

The mode of action of carriers in augmenting the rate of dyeing of disperse dyes with acrylic and polyester fibers is discussed in terms of the plasticizing action of the carrier. It is shown that the effectiveness of a carrier is determined by its ability to reduce the glass transition temperature of the fiber and not by the fiber swelling. The rate of dyeing as measured by the diffusion coefficient of the dye is shown to be uniquely related to the difference between the dyeing temperature and the glass transition temperature (T – T_g). In the light of these results, some aspects of carrier action in dyeing from perchlorethylene are discussed. Treatment of polyester fibers with carrier also increases crystallinity. Changes in diffusion for a series of copolyesters have been correlated with the long spacing obtained from small angle X-ray scattering (SAXS).     

Disperse dyeing of polyester fibers: Kinetic and equilibrium study

The effect of temperature on the dyeing rate constant k, diffusion coefficient D, time of half‐dyeing t_1/2 was evaluated for the dyeing of polyester fibers with two disperse dyes, an azo and an anthraquinone dye. Activation energies of diffusion E were calculated. The polyester dyeing equilibrium was also studied and the partition coefficient K and standard affinity Δμ° at various temperatures were determined for the anthraquinone dye. Standard enthalpy ΔH° and standard entropy ΔS° of dyeing were also obtained. The same equilibrium parameters were not obtained for the azo dye because of its dyeing behavior. A similar kinetic and equilibrium study was made for the pure azo and anthraquinone compounds free from the dispersing agents present in the commercial dyes and the results are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2785–2790, 2002; DOI 10.1002/app.10254     

舒适性聚酯纤维研究Ⅲ.共混改性聚酯纤维染色性能

共混改性聚酯纤维由于加入了含有磺酸基团的间苯二甲酸双羟乙酯-5-磺酸钠(SIPE)成分的添加剂,具有较好的阳离子染料可染性能,且阳离子染料的上染率在较大程度上取决于改性添加剂含量的高低。但对分散染料的上染率而言,添加量的影响并不显著。不论何种染料,纤维横截面的变化对于上染率的影响均不明显。碱处理后共混改性聚酯纤维对阳离子染料的吸收量有较大的增加,只不过达到一定程度后,上染率转而趋向下降。但对分散染料而言,其上染率基本上随减量率的增加呈现单一的下降趋势。     

Dispersant-free dyeing of polyester with temporarily solubilised disperse dyes

In an effort to overcome some of the environmental problems associated with the use of dispersing agents, four temporarily solubilised disperse dyes had previously been synthesised and characterised for use in dispersant-free polyester dyeing. In this paper the dyeing and fastness characteristics of these dyes on polyester fabrics have been examined. It was found that the optimum pH to guarantee a moderate rate of hydrolysis was 5, which allowed temporarily solubilised disperse dyes to be successfully applied to polyester without the use of dispersants. The dyebath remained stable during the dyeing procedure. The dyes exhibited good levelling and fastness properties on polyester.     

Dyeing behaviour of aqueous solutions of dispersant–free disperse dyes in the high–temperature dyeing of polyester (Part 1)

High–temperature dyeing of polyester with dye dispersions and dispersant–free disperse dyes dissolved in the presence of a surfactants mixture has been simulated with the aid of both a previously developed and a new mathematical model, and the exhaustion kinetics have been computed for three dyes with the aid of experimentally determined dyeing parameters. The correctness of the models was tested by experimentally determined exhaustion curves. An equilibrium in the system consisting of a substrate, dye and surfactant mixture has been investigated experimentally as a function of the temperature and of the concentrations of the dye.     

合成纤维及其混纺织物用染料的研究(Ⅲ)含β-羟乙基砜硫酸酯基活性分散染料在涤-棉混纺织物上的染色机理

本文探讨了含β-羟乙基砜硫酸酯基活性分散染料在涤-棉混纺织物上热熔染色各阶段的迁移及其存在形态.测定了染料的升华性能和气相转移.研究热熔条件对染料在涤-棉混纺织物上分配的影响及染料分子结构与分配的关系.由此提出了这类染料在涤-棉混纺织物上的热熔染色机理.     

One‐step dyeing of polyethylene terephthalate fabric,combining pretreatment and dyeing using alkali‐stable disperse dyes

In the conventional dyeing process, polyester and its blended fabrics are usually dyed in a weak acidic medium. In order to reduce cost and improve production efficiency, a new dyeing method – one‐step dyeing of polyethylene terephthalate fabrics, combining pretreatment and dyeing in alkali conditions – was investigated. The alkali‐stable disperse dyes Red 900, Red 902, Yellow BROB and Blue 825 were used to dye polyethylene terephthalate fabrics. The dyeing properties of polyethylene terephthalate fabrics in the case of one‐step dyeing at various pH values or sodium hydroxide concentrations were discussed in terms of colour yield, colour parameters and fastness. The performance of one‐step dyeing using alkali‐stable disperse dyes was excellent. The dyed fabric had good fastness. Wet processing could be combined and shortened. One‐step dyeing of polyethylene terephthalate fabrics could reduce the consumption of water and energy and improve production efficiency. One‐step dyeing of polyethylene terephthalate has potential application in cleaner textile production.     

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