Dyeing and fastness properties of vat dyes on meta-aramid woven fabric

meta-Aramid fibers have an excellent heat-resistant property and are widely used for protective clothings such as fire-fighter suit and racing suit. They can also be used as military uniforms such as flight suit or army uniform. Vat dyes are specially used for military uniforms owing to outstanding fastness properties, earth tone shade, and near infrared (NIR) camouflage. In this study, 100 % meta-aramid woven fabric was dyed with three vat dyes using an exhaustion method and their dyeing and fastness properties were investigated. Color yields of the vat dyes on the meta-aramid fabric were found to be dependent upon dyeing temperature, liquor ratio, amount of reducing agent, and amount of salt. Dyeing behavior of the vat dye on the meta-aramid fiber was very similar to that on cellulose fibers. It was found that the meta-aramid fabric dyed with 1% owf of C.I. Vat Green 1 satisfied the tolerance of the reflectance spectrum of forest green color in the Korean military standard. Thermal stability and mechanical property of the meta-aramid fabric did not significantly affected by the vat dyeing process. Wash and perspiration fastness was generally good but rubbing and light fastness was unsatisfied.     

Preparation of nano disperse dyes from nanoemulsions and their dyeing properties on ultramicrofiber polyester

Six nano disperse dyes were prepared using corresponding O/W nanoemulsions which were obtained with sodium laurylsulphate and caprylic triglyceride. The average particle size of the dyes prepared were in the range of 110–130 nm. Exhaust dyeing using nano dyes resulted in low exhaustion yields of 17–26 % on regular polyester fiber and 28–38 % on ultramicrofiber polyester. The observed low exhaustion yields of nano disperse dye can be explained by the solubilization of dye particles into surfactant micelles as well as the high stability of the nanoemulsions, these might reduce the capacity of dye uptake onto the fibers. However, higher K/S values of dyeings with nano dyes on ultramicrofiber sites compared to those on regular polyester sites suggested their potential to be more efficient dyes for finer denier microfiber polyesters.     

Reactive dyeing of meta-aramid fabrics photografted with dimethylaminopropyl methacrylamide

Aramid fibers have been known to difficult to dye with conventional dyes and dyeing techniques because of its extremely high crystallinity and compactness. In order to make the aramid fibers dyeable to a bright color in deep shade, meta-aramid fabrics were photografted under continuous UV irradiation with dimethylaminopropyl methacrylamide (DMAPMA) and benzophenone as a monomer and a hydrogen-abstractable photoinitiator respectively. Several factors affecting the photografting treatment of the meta-aramid fabrics were investigated including monomer and photoinitiator concentrations. ATR, ESCA and SEM analysis indicated significant alterations on the chemical structure and atomic composition of the photografted fabric surface and the fabric surface was covered with the grafted polymers. While the pristine meta-aramid fabrics showed no appreciable dyeability to the α-bromoacrylamide type reactive dyes, the grafted aramid fabrics showed the remarkably enhanced dyeability to the reactive dyes, which was proportional to the graft yield indicating the covalent bond formation between the dyes and the secondary amino groups in the grafted DMAPMA. In case of C.I. Reactive Red 84, a K/S value of 14.8 can be obtained with the grafted meta-aramid fabrics with a graft yield of 7.6 % (w/w). Also and the color fastness properties of the dyed fabrics was excellent in the conditions of washing, rubbing and solar irradiation.     

Acid dyeing properties of meta-aramid fiber pretreated with PEO45-MeDMA derived from [2-(methacryloyloxy)ethyl] trimethylammonium chloride

A diblock copolymer (PEO₄₅-MeDMA) derived from [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MeDMA) was synthesized and applied to the dyeing of the meta-aramid fibers with some acid dyes. This copolymer created positive charges on meta-aramid fiber surface and a strong attraction with anionic groups of acid dyes. Meta-aramid fabric was pretreated using the synthesized copolymer and then dyed with two commercial acid dyes. The dyeability was found to be directly dependent on the concentration of PEO₄₅-MeDMA, pH in the dyebath as well as dye concentration. The color fastness of the copolymer pretreated dyed fabric was also evaluated.     

Salt free reactive dyeing of cationized cotton

In this study 3-chloro-2-hydroxypropyltrimethylammonium chloride was used as a cationic agent to cationize cotton fabric by a pad-batch process. The cationized cotton samples were dyed with different reactive dyes containing various reactive groups. The dyeability of the cationized cotton samples with reactive dyes without salt was significantly improved due to an increase in the ionic attraction between the dye and cationized cotton. The results showed that the wash and dry rubbing fastness of the cationized cotton dyed with different reactive dyes are similar to those of the untreated cotton. However, the light fastness of some of the cationized fabric samples was improved.     

Synthesis and microbial studies of N-phenyl-2-(4-phenyl-thiazol-2-ylamino)-acetamide based disperse dyes and their dyeing performance on polyester fiber

Azo disperse dyes (D₁-D₁₃) were prepared by various diazotized aryl amines coupled with N-(phenyl)-2-[(4-phenyl-1,3-thiazol-2-yl)amino] acetamide. All the azo disperse dyes have been characterized by their percentage yield, UV-VIS spectroscopy, elemental analysis, IR spectroscopy, ¹H-NMR spectroscopy, and dyeing performance on polyester fiber. These dyes were applied to polyester fabric by HTHP method and their fastness properties were evaluated. All the dyes gave moderate to excellent fastness properties on polyester fiber. The main focus was to synthesize azo disperse dyes that give good dyeing property along with pharmacological activity. Therefore, the synthesized compounds were examined for their antimicrobial activity at various concentrations using well-known Kirby-Bauer disk diffusion method.     

Dyeing of meta-aramid fibers with disperse dyes in supercritical carbon dioxide

Dyeing characteristics of meta-aramid fibers were investigated in supercritical carbon dioxide by employing three disperse dyes and a carrier. The effects of dyeing temperature, pressure, time, dye concentration, CO₂ flow, and carrier concentration on dyeing properties were investigated. The results showed that meta-aramid fiber could be dyed in supercritical carbon dioxide. Its color depth was improved with increasing dyeing temperature, pressure, time, dye concentration, CO₂ flow, and carrier concentration. Moreover, the color depth could be significantly improved by adding the carrier. The dyeing procedure of supercritical carbon dioxide fluid did not influence the chemical structure and antistatic properties of the meta-aramid fiber. The maximum decomposition temperature and breaking strength of the dyed meta-aramid fiber are slightly increased. The dyed meta-aramid fiber in supercritical carbon dioxide had good fastness, which was rated at 4–5.     

Synthesis and application of alkyl-substituted disazo yellow dyes for unmodified polypropylene fiber

The several disazo dyes having different alkyl substituents were synthesized to dye unmodified polypropylene fiber. The affinity of the dyes onto unmodified polypropylene was increased with the increase of the length of alkyl substituents. Therefore, the heptyl-substituted dye having the longest alkyl group in this experiment showed very high color strength of dyeings with K/S value of over 24 at maximum absorption wavelength. The color fastnesses to washing, rubbing and light were also improved significantly for the longer alkyl substituted dyes, so that the heptyl-substituted dye exhibited a rating of 4∼5 for all kinds of fastnesses.     

Synthesis and spectral characterization of novel azomethine disperse dyes derived from pyrazolone moiety and their dyeing performance on polyester fabrics

A series of new azomethine dyes based on pyrazolone system have been synthesized via different routes. The solvatochromism for the dyes was evaluated with respect to spectroscopic properties in various solvents. The dyes were applied as disperse dyes on polyester fabrics and gave shade poor to excellent light fastness, washing, perspiration, sublimation, and rubbing fastness properties. Also the position of color in CIELAB coordinates (L*, a*, b*) and K/S value were investigated.     

Synthesis and application of alkyl-substituted high chroma yellow dyes for unmodified polypropylene fiber

A series of new monoazo yellow dyes having different alkyl substituents was synthesized to dye unmodified polypropylene fiber. Color hue of the dyes exhibited light yellow with very high chroma enough to use as yellow primary color dyes. The affinity of the dyes onto unmodified polypropylene was increased with the increase of the length of alkyl substituents. Therefore, the hexyl-substituted dye having the longest alkyl group in this experiment showed very high color strength of dyeings with K/S value of over 26 at maximum absorption wavelength. The color fastnesses to washing, rubbing and light were also improved significantly for the longer alkyl substituted dyes, so that the hexyl-substituted dye exhibited a rating higher than 4∼5 for all kinds of fastnesses.     

Synthesis,spectral characterization of azo dyes derived from calix[4]resorcinarene and their application in dyeing of fibers

Seven new upper rim functionalized azocalix[4]resorcinarene dyes have been synthesized by coupling calix[4]resorcinarene with different diazo compounds of p-chloroaniline, p-nitroaniline, p-toludine, p-anisidine, p-aminobenzoic acid, o-aminophenol, and aniline. The characterization of these dyes has been carried out by elemental analysis, FT-IR, ¹H- and ¹³C-NMR. Effect of solvents of varying dielectric constants on the absorption spectra of substituted and unsubstituted azocalix[4]resorcinarene dyes have been examined by UV-vis spectrophotometer. These azocalix[4]resorcinarene dyes have also been used for dyeing textile fibers like cotton, silk, and wool. Their dyeing and fastness properties have also been discussed.     

Study on the dyeing properties of hemicyanine dyes. I. Acrylic fabrics

Three hemicyanine dyes were employed in dyeing acrylic fabrics following traditional cationic dyeing procedures. The influence of the substituting groups of the dye molecule on the sorption rate and sorption isotherms was analyzed. The results showed that those dyed acrylic fabrics using hemicyanine dyes had obvious fluorescent effect in the spectra range 550–750 nm. In addition, according to the EN-471 standard (2003), the chromaticity of dyed acrylic fabric was calculated to evaluate whether hemicyanine dye could meet the requirements of the fluorescent dye for high visibility warning clothing.     

Adsorption and dyeing characteristics of reactive dyes onto cotton fiber in nonionic Triton X-100 reverse micelles

The nonionic reverse micelles used for dyeing cotton fiber were prepared with a non-ionic surfactant Triton X-100 (TX-100) by injecting small amount of reactive dye aqueous solution. The adsorption capacity of three water-soluble anionic azo dyes including Reactive Blue 222, Reactive Red 195 and Reactive Yellow 145 onto cotton fiber was investigated. The Langmuir and Freundlich isothermals were employed to model the adsorption data. In addition, the color strength and fixation rate of cotton fabrics dyed in the reverse micelles and bulk water were examined and compared. The salt and alkali as influencing factors were also discussed. The FT-IR spectra were employed to study the polarity of water added in reverse micelles. The results indicated that the adsorption of the dyes onto cotton showed better agreement with Langmuir model. The adsorption process was monolayer adsorption. Reactive Yellow 145 with lower negative charge and higher hydrophilicity exhibited the higher adsorption capacity. The fixation percentage and color strength of the cotton fiber dyed in TX-100 reverse micelles was higher than those in bulk water. The polarity of water in TX-100 reverse micelles was lower than that in bulk water.     

Azocalix[4]pyrrole dyes: Application in dyeing of fibers and their antimicrobial activity

The dyeing performance of the azocalix[4]pyrrole dyes on fibers like nylon, wool, acrylic, and silk have been determined. Their fastness properties towards light, water, washing, and acid-alkali perspiration have been studied. The position of color in CIELAB coordinates (L*, a*, b*, H, and C*) was assessed. The azocalix[4]pyrrole demonstrated good antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Aspergillus niger. These super molecules exhibit bright shades on fabric with very good fastness properties.     

Synthesis,characterization, and properties of ethoxylated azo dyes

The nonionic surfactant properties of ethoxylated azo dyes, such as cloud point and surface tension have been investigated. The synthesized ethoxylated azo dyes could dye polyester fabric without any special pre-treatment. When the average number of ethylene oxide (EO) in the ethoxylated azo dye reached 6, its fixation could exceed 90% from the thermosol dyeing process. The average degree of condensation of ethylene glycol in the chain was interrelated with the dyeing results and did not affect on the maximum absorption wavelength (λmax) of the polyoxyethylene dye. When the average length of polyoxyethylene chain decreased, the molecular weight of dyes became smaller and the fixation of dyes was improved.     

Colorimetric studies of benzoquinoline based hot brand monoazo reactive dyes and their dyeing performance on various fibers

A series of hot brand monoazo reactive dyes (9a-l) were obtained by the coupling of diazotized 1Hbenzo[ g]pyrazolo[3,4-b]quinoline-3-ylamine (5) with various cyanurated coupling components (8a-l) in good yield. Synthesized dyes were characterized by various spectroscopic techniques. Their dyeing performances as reactive dyes have been assessed on silk, wool, and cotton fabrics. The percentage dye bath exhaustion and fixation on different fibers were found to be very good. The dyed fabric showed moderate to very good light fastness and good to excellent washing and rubbing fastness properties. Spectral properties and colorimetric data of synthesized dyes have also been studied in detail.     

Dyeing and fastness properties of vat dyes on a novel regenerated cellulosic fiber

enVix is a novel regenerated cellulosic fiber, which is prepared from cellulose diacetate fiber using environmentally friendly manufacturing process. Vat dyeing properties of the enVix were investigated and compared with those of regular viscose rayon. The enVix exhibited better dyeability than viscose rayon. The colour yields of vat dyes on the enVix were found to be dependent on dyeing temperature as well as the amount of levelling agent and salt. Good build-up and good to excellent fastness properties were obtained on the enVix fabric.     

Dyeing properties of bi-functional reactive dyes on a novel regenerated cellulosic fiber

Three bi-functional reactive dyes such as Bis(vinylsulphone) type, Bis(monochlorotriazine) type and Bis(mononicotinotriazine) type were applied to regular viscose rayon and new regenerated cellulosic fiber (enVix®) which was prepared from cellulose acetate fiber by the hydrolysis of acetyl groups, and their dyeing properties and fastness properties were compared.enVix exhibited better dyeability and fastness than regular viscose rayon and these results were also explained by the differences in the supramolecular structure of these two fibers.     

Synthesis and spectral properties of phthalimide based alkali-clearable azo disperse dyes

The synthesis of a series of phthalimide based azo disperse dyes and their spectral properties were investigated. The azo dyes containing phthalimide and N-methyl phthalimide structure in diazo component were synthesized in order to compare their spectral properties. The synthesized dyes developed the color of yellow to violet and the N-substitution of the phthalimide gave a bathochromic effect on the color change. Most of the synthesized dyes exhibit negative solvatochromism so that the absorption band of dyes moves toward shorter wavelengths as the polarity of the solvent increases. In the case of halochromic effect, the bathochromic shift decreased steadily with the general electron donating capacity of the substituents in the coupling component, and became negative especially when more powerful electron donating groups are present in the coupling components ring.     

Dyeing properties of nylon 66 nano fiber with high molecular mass acid dyes

Research and development of nano fiber products is very active over the world. Physical characteristics and dyeing properties of nylon 66 nano fiber were investigated in this study. X-ray diffraction, DSC, analysis of amino end group, and water absorption were performed to get information concerning physical properties of nano fiber. Nylon 66 nano fiber was dyed with high molecular mass acid dyes. Effects of dyeing temperature, pH of dyeing solution, and concentration of acid dyes on dyeing properties such as rate of dyeing and the extent of exhaustion, were examined and compared to those of regular fiber. It was found that nano fiber adsorbed acid dyes at lower temperature, got rapidly dyed, and its extents of exhaustion at specific dyeing temperature were higher than regular fiber. It was also observed that nano fiber could adsorb a large amount of acid dye without a significant loss in the extent of exhaustion. Washing fastness of the dyed nano fiber was lower by 1/2∼1 grade, light fastness by 1 grade than the dyed regular fiber.