High Light-Fastness Acid Dyes Synthesized from Corresponding Anthraquinone Chromophore Utilizing a Sulfonation Reaction. I. Dye Synthesis and Characterization

As the diameter of polyamide fibers decreased to finer denier, the dyeing fastness tends to be deteriorated due to the increase of their surface area, particularly both light fastness and wash fastness. In this study, three acid dyes were synthesized utilizing a sulfonation reaction starting from corresponding hydrophobic dye (for yellow and red dye) and dye intermediate containing a sulfonic acid group (for blue dye), those featured by high light fastness property. A Gaussian structural prediction model was used to determine the structure of the acid dyes prior to dye synthesis, and the optimal structures of three acid dyes were analyzed. Dye structures prepared were confirmed by ¹H-NMR, mass spectroscopy, and elemental analysis. By using a UV-vis spectrophotometer, the absorption maxima and molar extinction coefficient were also measured for three acid dyes comparing to that of the corresponding disperse dye or blue dye intermediate. Judging from spectroscopic data, the introduction of sulfonyl groups led to increase of molar extinction coefficient and a bathochromic shift.     

Synthesis of cationized anthraquinone dyes and their dyeing properties for meta-aramid fiber

Due to compact structure of meta-aramid fiber caused by the intermolecular hydrogen bondings of amide groups, the degree of crystallinity increased, thus its poor dyeing properties arises. Among commercial dyes used in many previous researches, the basic dyes showed comparatively higher exhaustion yields as comparing to those of disperse dyes and acid dyes. The anthraquinone moiety was adopted for good performances of light fastness on meta-aramid fiber. In this study, eight of anthraquinone dye was synthesized. The three of them were obtained from chloro-anthraquinone, by Ullmann reactions with the corresponding heterocylic residues such as morpholine and one of them was obtained from lueco quinizarine by condensation with the corresponding heterocylic residues. The others were prepared by quaternization from dyes above. The synthesized disperse and cationic dyes were dyed on meta-aramid fibers and investigated for their build-up dyeing properties and wash fastness.     

Dyeing behavior of chemically modified poly(1,4-phenylene sulfide) fiber towards disperse,anionic, and cationic dyes

Poly(1,4-phenylene sulfide) (PPS) exhibits good dimensional stability and flame retardant characteristics but its commercial development as fibers is highly limited due to lesser dyeing and finishing characteristics. Hence in the present study, we focused on the anionic and cationic modifications of PPS to enhance its dyeing ability towards disperse, cationic, and anionic dyes. Novel sulfonation and chloromethylation-quaternization of PPS fiber were carried out to achieve an industrially viable dyeing process methodology. The chemically modified PPS fiber is dyed with disperse, cationic, and anionic dyes, and the dyeing adsorption efficiency is quantitatively studied using a dye-o-meter equipped with UV-visible absorption spectroscope. The ideal parameters for dye adsorption were determined as a function of dyeing time, material-toliquor ratio, dyeing temperature, carrier concentration, sulfonation, and chloromethylation. The fastness properties of the dyed fabrics were also studied. Overall, with a maximum dye uptake of 99 % and 90 % achieved for sulfonated PPS and quaternized PPS respectively, the optimized conditions can be readily scaled-up to the commercial dyeing of PPS fiber with disperse, anionic, and cationic dyes.     

Effect of surrounded air atmospheric plasma treatment on polypropylene dyeability using cationic dyestuffs

The dyeing properties of the polypropylene (PP) fabrics using cationic dyestuffs were investigated after surrounded air atmospheric cold-plasma treatment. Surrounded air plasma (SAP) was used to modify fabric surface and to optimize the effects of some discharge parameters on dyeability. Surface morphology and physical-chemical properties of plasma treated fibers were also characterized by Fourier transform infrared attenuated total reflection spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Activated surfaces by SAP were grafted with different compounds: 6-aminohexanoic acid, acrylic acid, and hexamethyldisiloxane. Dyeing the plasma-induced grafted PP fabric with basic dye was quite satisfactory when high color strength and good fasteness were considered.     

Dyeing properties and color fastness of 100% <Emphasis Type="Italic">meta</Emphasis>-aramid fiber

Dyeing characteristics and fastness of 100 % m-aramid fiber with some commercial dyes were investigated on various dyeing conditions, such as using a swelling agent and electrolyte as auxiliaries. Among commercial dyes used, the basic dyes showed comparatively higher exhaustion yield comparing to those of disperse dyes and acid dyes. Under acidic conditions in the range pH 3 to 5, preferably between pH 3 and 4, the stability of cationic dyes could be enhanced leading to higher adsorption. Dye exhaustions of trichromatic dyes were increased proportionally to concentration of swelling agents ranging from 1 to 4 g/l. The addition of electrolyte provided increased K/S values after washing process compared with those of blank dyeings, where the greatest effect was observed with NaNO₃.     

Novel cationic softener containing MCT reactive dyes for cotton: Simultaneous dyeing and functional finishing

The cationic softeners containing MCT (monochloro-s-triazinyl) reactive dyes were employed on the dyeing of cotton fabrics. The substantivity, exhaustion, and fixation of the dyes were investigated. It was found that these functional dyes could be effectively introduced to cotton fibers to achieve simultaneous coloration and functional finishing effects. All the dyed fabrics exhibited softening efficacy. The dyes offered excellent washing fastness on cotton substrate. Light fastnesses of the dyes on the substrate were poor.     

Synthesis and application of alkyl-substituted red dyes for unmodified polypropylene fibers

Following the previous studies regarding blue and yellow dyes, a series of new red dyes having different length of alkyl substituents on the same chromophore were synthesized in order to dye unmodified polypropylene fiber. The affinity of the dyes onto unmodified polypropylene fiber was increased with the increase of the length of alkyl substituents. Therefore, the longest hexyl-substituted dye showed very deep shade of dyeing with K/S value of around 30 at maximum absorption wavelength. Within the range below 2 % o.w.f., the exhaustion (%) showed more than 80 %. The color fastnesses to washing, rubbing, and light of the dyeings were also improved greater for the dyes having longer alkyl substituents than the shorter ones. Since color hue of the dyes exhibited very strong red, they could be considered to be used as the primary red color dyes for unmodified polypropylene fibers.     

Hydrophilic modification of PET fabric via continuous photografting of acrylic acid (AA) and hydroxyethyl methacrylate (HEMA)

Poly(acrylic acid) and poly(hydroxyethyl methacrylate) were introduced onto PET fabrics by UV-induced photografting to improve its hydrophilicity. Several factors affecting the photografting were studied including irradiation energy, monomer, and photoinitiator (PI) concentrations. ATR and ESCA analyses proved successful grafting of the two monomers onto PET. Morphology of fabric surface was examined using FE-SEM. Both zeta potential and water wetting time of the grafted PET fabrics decreased with increasing grafting yield. Also cationic dyeability of the grafted PET fabrics increased because of the increased electrostatic interactions between the anionic dyeing sites and cationic dyes.     

Imparting disperse and cationic dyeability to polypropylene through melt blending

The present paper deals with improvement in disperse dyeability as well as imparting of cationic dyeablility to difficultly dyeable polypropylene by a melt blending technique. Isotactic polypropylene (PP) was blended with fibre grade polybutylene terephthalate (PBT), cationic dyeable polyethylene terephthalate (CDPET) and polystyrene (PS), individually. The resulting binary blends were spun and drawn into fibres at draw ratio 2, 2.5, and 3. The compatibility of blends, structural changes of fibres in terms of X-ray crystallinity, relative crystallinity, sonic modulus, birefringence and thermal stability were examined. The blended fibres were found to be disperse dyeable by the conventional method of high temperature and high pressure dyeing. And this dyeability increased with increase in the level of substitution. PP/CDPET blend also exhibited dyeablility with cationic dyes in addition to that with disperse dyes. The optimum level of blending was predicted keeping in view of tenacity and thermal stability of melt blend fibres. The wash fastness properties of the dyed fibres were found to be of high rate.     

The effects of UV irradiation exposure on the structure and properties of polypropylene/ZnO nanocamposite fibers

Unfilled polypropylene and polyropylene/ZnO nanocomposite fibers were produced using a melt spinning apparatus; then the fibers were exposed to UV irradiation. The structure and properties of the fibers were examined using scanning electron microscopy, tensile measurements, wide angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR) spectroscopy, birefringence measurements and differential scanning calorimetry (DSC). Following 150 hours of exposure to UV irradiation, some transverse cracks on the surface of unfilled polypropylene fibers were observed. It was observed that both carbonyl and hydroperoxide indexes, which are the criteria for the detection of UV degradation of the fibers, were increased due to the increase in the UV irradiation exposure time and the increase in these indexes was smaller for nanocomposite fibers than those of unfilled Polypropylene fibers. It was also observed that crystallinity, crystallite size and total molecular orientation of UV irradiated nanocomposite fibers were increased in comparison with non-irradiated nanocomposite fibers. It was also found that the extent of increase in molecular orientation of the fibers was higher comparing to that for the nanocomposite fibers due to the UV irradiation exposure for the unfilled polypropylene fibers. Tensile properties of both unfilled and nanocomposite fibers were decreased after UV irradiation; this reduction correlated with the extent of the increase in molecular degradation of the fibers, as determined by measuring carbonyl and hydroperoxide indexes.     

Coloration of ultra high molecular weight polyethylene fibers using alkyl-substituted anthraquinoid blue dyes

UHMWPE fibers were dyed with a series of anthrquinoid blue dyes having different length of alkyl substituents at general dyeing condition. The dyeability was investigated at various conditions and fastness of the dyeings was examined. As the length of alkyl substituents increased, the dyeability toward UHMWPE fibers tends to be improved gradually. Color strength of the fabrics was increased with the increase of dyeing temperature from 100 to 130 °C. From the dyeing rate, equilibrium dyeing at 130°C was achieved at 2–3 h. The tensile strength of UHMWPE fibers after dyeing at 130 °C for 1 h was maintained at a level of 95 % of untreated fiber. However, at prolonged dyeing time at 130 °C, the tensile strength was significantly decreased to a practically unacceptable level. The color fastnesses to washing, rubbing and light of the dyeings were very good showing higher than 4 ratings.     

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.     

One-Bath Union Dyeing of Wool/Acrylic Blend Fabric with Cationic Reactive Dyes Based on Azobenzene

Three unreported cationic reactive dyes based on azobenzene were synthesized using a novel synthetic route. Synthesized dyestuffs containing three primary color dyes were characterized by FTIR, H-NMR, LC-MS, Element Analysis and UV-vis spectroscopic techniques. The absorption spectra of dyes were measured in three solvents with different polarities. The dyeing and color fastness properties of three cationic reactive dyes on wool, acrylic and wool/acrylic blend fabrics were determined. The optimum pH for wool and acrylic fabrics were 6 and 5, respectively. Effect of temperature, time on dyeing properties and color fastness properties on wool fabric showed the same tendency with acrylic fabric. The K/S value of wool fabric dyed with three dyes was similar to that of acrylic fabric when both fabrics were dyed simultaneously in the same dyebath using low dye concentration. Wool/acrylic blend fabric dyed with three cationic reactive dyes using onebath one-step method achieved good union dyeing property and excellent color fastness.     

Surface modification of poly(lactic acid) by UV/Ozone irradiation

Hydrophobic poly(lactic acid), PLA, was modified to give hydrophilicity and dyeability to cationic dyes via UV/O₃ irradiation. The UV irradiation treatment caused ester linkage of PLA surface to break down resulting in reduced molecular weight and generation of new photooxidized products as indicated in subtracted ATR spectra and ESCA analysis. It was found that water contact angle decreased from 61 ° to 39 ° and surface energy slightly increased with increasing UV energy, which was attributed to significant contribution of polar component rather than nonpolar component resulting from the surface photooxidation of PLA. Also the surface treatment increased dyeability of PLA to C.I. Basic Blue 41 in terms of both K/S and %E. The increased dyeability may be due to photochemically introduced anionic and dipolar dyeing sites which electrostatically interact with the cationic dye as ascertained by the decreased zeta potential and its pH dependence of the modified PLA.     

Design,characterization, dyeing properties,and application of acid-dyeable polyurethane in the manufacture of microfiber synthetic leather

The difficulty in dyeing microfiber synthetic leather filled with ordinary polyurethane presents a significant challenge in maintaining the uniformity and highly realistic appearance of the resulting products. In the present study, a type of acid-dyeable polyurethane (PU-MDEA; MDEA=N-methyldiethanolamine) was synthesized, and its chemical structure and dyeing properties were investigated. Nuclear magnetic resonance analysis indicated that cationic groups were successfully incorporated into the PU-MDEA backbone via chain extension using MDEA. The amorphous nature of PU-MDEA was determined by differential scanning calorimetry, X-ray diffraction, and polarizing optical microscopy. Owing to the strong binding between these cationic groups and acid dye, as well as the reduced resistance to dye penetration, PU-MDEA showed better dyeability toward the acid dyes studied herein when compared with the control sample (microfiber synthetic leather filled with ordinary polyurethane). The adsorption isotherm experiment revealed that the dyeing process conformed to the Langmuir model, thereby indicating that the acid dyes attached to PU-MDEA via strong ionic bonding rather than van der Waals forces or hydrogen bonding. Additionally, it was found that the wastewater resulting from the dyeing of the microfiber synthetic leather filled with PU-MDEA exhibited environmentally friendly characteristics when compared with that displayed by the control sample (microfiber synthetic leather filled with ordinary polyurethane). Thus, the current results show the potential of PU-MDEA, as a filler, in the manufacture of microfiber synthetic leather to achieve fast dyeing rate, high dye uptake, and good color fastness, thereby improving the uniformity and highly realistic appearance of the resulting products.     

Synthesis and Structure Properties of Flame Retardant and Cationic Dyeable Polyamide 6 Modified with 5-sulfoisophthalic Acid Sodium and Melamine Cyanurate

Unmodified polyamide 6 commonly dyed with acid dyes, and has no flame-retarded properties. So they are flammable and can be easily stained by foods or drinks that contain acid dyes. However, the acid groups react with amino groups that existed at the end of PA6 chain while using cationic dyes. Thus, the acid dyes can be washed immediately. In this study, the flame retardant and cationic dyeable polyamide 6 (FRCD-PA6) modified with 5-sulfoisophthalic acid sodium (5-SSIPA) and melamine cyanurate (MCA) was successfully prepared by the two-step-melt polymerization method. Firstly, cationic dyeable polyamide 6 (CD-PA6) was prepared with sodium salt from 5-sulfoisphthalic acid. Secondly, melamine cyanurate, as an efficient flame retardant, was blended into the reaction. The chemical and crystalline structures of FRCDPA6 were characterized by the Fourier transform infrared spectroscopy (FT-IR) and wide angle X-ray diffraction (XRD). Their thermal properties were tested by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and morphology was analyzed by SEM, respectively. It had been measured to prove the dispersion of 5-SSIPA and MCA on polyamide 6 matrix. Incorporating with 5-SSIPA created more amorphous regions and rose up the dyeing rate easily, with a highest dyeing rate for about 96.79 %. The effect of varying MCA content on the composites showed more flame retardant and made better heat-resistance. Moreover, with the appropriate addition of MCA content, the limit oxygen index (LOI) reached up to 27, less smoking, no more black smoke, droplet phenomenon was slightly, and flame resistance had greatly improved. Because of the good synergy between 5-SSIPA and MCA, a kind of novel modified polyamide 6 which own both cationic dyeable and efficient flame retardant properties was born.     

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.     

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.     

Synthesis and application of phthalimide disperse dyes

Three azo dyes had been synthesized using N-propyl substituted, dibromo-substituted and dicyano-substituted phthalimides as diazo components. All of the synthesized intermediates and dyes have been characterized by MS, 1H-NMR and IR analyses. The dyeing behaviour and fastness properties of these dyes had been investigated. The absorption maxima of the dyes were observed in the range 360 to 700 nm. The results indicated that dyes caused hypsochromism effect after -Br substitution and dyes caused bathochromism effect after -CN substitution. IR spectra of hydrolyzed dye showed that C=O groups appeared under relatively mild alkaline conditions. Compared with electron density, steric hindrance effect is an more important influence factor than electron density in hydrolysis reaction process. Exhaustion of dyed polyester/elastane fabrics decreased obviously as the pH value increased. In order to ensure dyeing levelness, heating rate of prepared dyes will be strictly controlled. Due to alkali-clearable property and interaction energy of dye-fiber and dye-dye, the dyes have good colorfastness.     

Dispersant-free dyeing of poly(lactic acid) knitted fabric with temporarily solubilized azo disperse dyes

Poly(lactic acid) (PLA) is known for environmentally friendly material as it is derived from annually renewable crops and biodegradable. Dispersant-free dyeing of PLA fabric with three temporarily solubilized azo disperse dyes which contain β-sulfatoethylsulfonyl group was investigated and their dyeing and fastness properties were compared with those of commercial disperse dyes. The temporarily solubilized azo disperse dyes were successfully applied to PLA fabric without the use of dispersant. The color yield on PLA fabric was dependent on dyebath pH and dyeing temperature as well. The optimum results were obtained at pH 7-8 and 110 °C. The dyes showed markedly higher color yield on PLA fabric when compared to commercial disperse dyes. Wash fastness was very poor to poor but light fastness was good. The COD levels of the dyeing effluent from the temporarily solubilized disperse dyes were considerably lower than those from commercial disperse dyes.