The dyeing of nylon with a microencapsulated disperse dye

Melamine resin microcapsules containing CI Disperse Blue 56 were prepared by in situ polymerisation. The microcapsules were characterised by their thermal properties and morphology, such as particle size and particle size distribution. The dyeing behaviour of the microcapsules on nylon 6.6 was evaluated. The microencapsulated dye exhibited good build-up, levelness and fastness properties. It has been demonstrated that microencapsulated disperse dye can be used to replace commercial disperse dyes in dyeing polyamide fabric without dyeing additives, and the resulting effluent can be easily recycled after filtration.     

Decolourisation of leather dye by ozonation

Sewage and industrial effluent treatment plants are installed with primary and secondary biological treatment units to reduce the discharge of pollution load into the environment. These treatment plants normally reduce the organic load in terms of BOD but not the pollution load in terms of inorganic salts (total dissolved solids—TDS) and colour in the effluent. To eliminate the contamination of ground and surface water bodies and to conserve water sources, the regulatory authorities have taken very stringent regulations to implement zero liquid discharge (ZLD) for industrial effluents, i.e., water recovery from wastewater and reuse. It is difficult to recover water from secondary treated wastewater directly, as it does not meet the reverse osmosis feed requirements. In order to achieve the feed requirements, different tertiary treatment methods are being tried. In this study, removal of colour due to residual dyes has been attempted using ozone. The main purpose of this study is to decolourise the dye used in leather processing. Also, the effect of pH and dye concentration on dye decolourisation has been investigated. From the study it has been observed that maximum decolourisation efficiency up to 97% could be achieved for the pH values (4,7, 9 and 11) and dye concentrations (30, 65, 180 and 360 mg/L) studied.     

Dyeing wool packages with continuous dosage of dye

Integration dyeing of wool packages by Lanaset dyes has been examined. Absorption kinetics were found to be governed by the Cegarra-Puente equation, giving an apparent activation energy of 104 kJ/mol. The levelness obtained by integration dyeing at various temperatures and dye concentrations were compared with that obtained by following the standard method. Similar values were observed in both systems.     

皮革黑染色废液的处理

用“絮凝－吸附－沉淀”法对皮革黑染色废液进行处理。结果表明：脱色率大于９６％,ＣＯＤｃｒ去除率为９２．４％,达到了国标排放标准,令人满意。     

Dyeing of cotton and jute with tea as a natural dye

Cotton and jute fabrics were dyed with an aqueous extract of tea, containing tannins as the main colorant species. The dyeing was carried out with and without metal salts as mordants, using three different dyeing methods: pre-mordanting, meta-mordanting and post-mordanting. The resulting wash and light fastnesses of the dyed fabrics were good to excellent. The colour of the fabrics was investigated on computer colour matching system in terms of K/S , and CIELAB colour-difference values. Deep shades ( K/S = 3.9) were obtained for jute in acidic media, while cotton fabrics could be dyed in medium depths ( K/S = 2.0) under identical conditions of dyeing.     

Dyeing of cationised cotton with acid dyes

The production of cationised cotton fabrics, via Sandene 8425, 1, 1-dimethyl-3-hydroxy azetidinium chloride and 1, 1-diethyl-3-hydroxy azetidinium chloride, greatly enhances the exhaustion and fixation of acid dyes. This paper shows that these dyes can be used in the absence of salt in a neutral medium. Wash fastness, light fastness and other properties were studied.     

Dyeing of nylon 6 fabric with a bifunctional sulphatoethylsulphone reactive disperse dye

A bifunctional reactive disperse dye containing two temporarily anionic sulphatoethylsulphone groups was synthesised and applied to nylon 6 fabric by exhaust dyeing at a variety of pH levels and temperatures. A monofunctional reactive disperse dye containing one temporarily anionic sulphatoethylsulphone group was also synthesised, and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and total fixation yield under alkaline conditions. The results also indicate that the introduction of two temporarily anionic sulphatoethylsulphone groups of the bifunctional dye gave an enhancement in dyeing performance compared with that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.     

Improving the dyeing properties of textiles via utilization of redox systems. II. Dyeing of nylon-6 with acid dye

Redox systems based on potassium, sodium or ammonium peroxodisulphate or potassium periodate as oxidant and glucose, thiourea, sodium thiosulphate or potassium pyrosulphite as reductant were incorporated in the dyeing bath of nylon-6 under a variety of conditions. An acid dye, namely Kiton Scarlet 4 R was used. The colour strength and dye fixation enhanced outstandingly in presence of the redox system, depending upon kind and concentration of the redox components. Raising the dyeing temperature from 30 to 60°C caused significant improvement in colour strength. The same holds true for duration of dyeing up to 60 min. Beside association of the dye with nylon-6 by salt-like bond, a free radical mechanism was suggested.     

Dyeing of nylon 6 fabric with a new bifunctional vinyl sulphone reactive disperse dye

A new bifunctional reactive disperse dye containing a temporarily anionic sulphatoethylsulphone and a nonionic disulphide bis(ethylsulphone) groups was synthesised and applied to nylon 6 fabric by the exhaust dyeing at a variety of pH and temperature conditions. A monofunctional reactive disperse dye containing only nonionic disulphide bis(ethylsulphone) group was also synthesised and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and fixation values at pH 6 and 120 °C. The results also indicate that the combination of temporarily anionic and nonionic reactive groups of the bifunctional dye provided great enhancement in dyeing performance compared to that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.     

Dyeing of cotton with a bifunctional disulphide bis(ethylsulphone-sulphatoethylsulphone) disazo reactive dye

A new bifunctional disazo reactive dye of a temporarily high molecular structure based on a disulphide bis(ethylsulphone-sulphatoethylsulphone) reactive system was synthesised and applied to cotton fabric. This dye displayed good primary exhaustion under different neutral exhaustion conditions. The results assessed for the alkaline exhaust dyeing indicate that the disulphide bis(ethylsulphone-sulphatoethylsulphone) dye showed higher exhaustion and fixation values compared to those obtained with the commercial CI Reactive Black 5. The fastness properties of the disulphide dye were similar to those of the commercial dye. Received: 24 March 2005; Accepted: 15 June 2005.     

Modified polyurethane with improvement of acid dye dyeability

This article concerns the modification of polyurethane using polyamide 6,6 prepolymer to improve the dyeability properties of the polyurethane copolymer with acid dye. First, the carboxyl‐terminated polyamide 6,6 prepolymer was synthesized from adipic acid and 1,6‐diaminohexane. The isocyanate‐terminated polyurethane prepolymer was also synthesized from polytetramethylene glycol and 4,4′‐diphenylmethane diisocyanate in N,N‐dimethylformamide. The polyurethane prepolymer was then extended with a mixture of 1,4‐butanediol and the polyamide 6,6 prepolymer (molar ratios of 1,4‐butanediol to prepolymer being 100%, 75%, 50%, and 25%, respectively). Finally, the poly(urethane–amide) copolymers were dyed with acid dyes. The chemical, physical, and the dyeing properties of the poly(urethane–amide) coploymers are discussed. From the experimental results, it is found that the inherent viscosity of poly(urethane–amide) coploymers is increased with the increasing amount of polyamide content. The structure is proven by infrared spectra, which exhibits the absorption peaks of urethane and amide groups as we expected. From the differential scanning calorimetry measurements, it is found that the poly(urethane–amide) coploymers have two‐phase structures and good phase separation. There are four transition temperatures (T_gs, T_gh, T_ms, and T_mh), but only those copolymers in PTMG 2,000 series possess T_ms. Moreover, the T_gs is found to change with the length of soft segment, and the T_gh is increased with the increasing amount of polyamide content. Also, the dyed copolymers exhibit higher T_gh than those without dyeing of dye molecule, but the T_gs is not obviously changed. For mechanical properties, it is indicated that both the modulus and the strength of the coploymers are higher than those of unmodified polyurethane, but they are lowered after being dyed with dye molecule due to further separation of intermolecular distance of the dyed polyurethanes. For dye uptake in dyeing properties, it is found to increase with increasing amount of polyamide content. For dye fastness, the dyed copolymers exhibit higher grade of water fastness than that of unmodified polyurethane. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1397–1404, 2003     

Dyeing of cellulose by direct dye in aqueous sodium alginate solution

Dyeing of cellulose by direct dye in aqueous sodium alginate solutions containing sodium chloride has been studied to interpret thermodynamically the role of sodium alginate on the adsorption equilibrium of dye on cotton. The result has been compared with that of sodium chloride (low-molecular inorganic electrolyte) by an adsorption model on cellulose. We have inferred, by the membrane-equilibrium theory, that the dye has been concetrated into the internal solution of cellulose because of the presence of sodium alginate in the bulk solution.     

Dyeing of polyamide granulate with preliminary treatment with acetic acid solution

It was found that preliminary treatment of PCA granulate with a dilute solution of CH₃COOH sharply increases the rate and degree of sorption of acid dyes by PCA granulate. A technological regime for dyeing PCA granulate with acid dyes was proposed and approved in industrial conditions; it allows increasing the intensity of the color by several times with almost total extraction of the dye from the bath.Ivanovo State Academy of Chemical Engineering. Translated from Khimicheskie Volokna, No. 4, pp. 35–37, July–August, 1996.     

Dyeing properties of soya fibre with reactive and acid dyes

In order to determine the most suitable type of dye for soya bean fibre, the dyeing properties of three acid dyes and three bifunctional reactive dyes were compared. Additionally, the effect of a range of reactive groups on dyeing performance were studied, including difluorochloropyrimidine, monofluorotriazine, monochlorotriazine and β-sulphatoethyl sulphone, and of these the first was found to perform best. Irrespective of reactive group, however, the main factor affecting build-up was found to be the substantivity of the dye for soya fibre. The monofunctional reactive dyes in general were found to exhibit good wash fastness.     

Dyeing of nylon 66 with a disperse-reactive dye using supercritical carbon dioxide as the transport medium

Nylon 66 fabric was dyed with a disperse-reactive yellow dyestuff which was synthesised in our laboratory, using a supercritical carbon dioxide dyeing process. The structure of the disperse-reactive yellow dyestuff and its covalent bond with nylon 66 fibres were confirmed by FTIR, NMR, EA and MS analysis. The nylon fabric was also dyed with CI Disperse Yellow 3 and the dyeing results compared. Colour yield values were measured for both dyed fabrics, with those of the disperse-reactive dye showing much better values than CI Disperse Yellow 3. Wash fastness of the fabric dyed with the disperse-reactive yellow dye was tested by the ISO 2 method and showed excellent results. Light fastness was tested by the ISO 105 B05 method and the results were satisfactory. The results obtained indicate fabric immersed in supercritical carbon dioxide does not undergo any fibre damage.     

Hydrothermal preparation of Zn2SnO4 nanocrystals and photocatalytic degradation of a leather dye

Zinc stannate (Zn₂SnO₄) powder was prepared by a hydrothermal process at 200 °C for 12 h. The material was characterized by X-ray-diffraction (XRD) and N₂ adsorption–desorption isotherms. The synthesized sample presented a pure phase, an average nanocrystal size of about 19 nm, a surface area (BET) of about 41.8 m² g^?1 and total pore volume of about 0.19 cm³ g^?1. Its photocatalytic activity was tested by the degradation of the leather azo-dye, Direct Black 38, in aqueous solution under UV irradiation. Adsorption kinetic data showed that the pseudo-second-order model was the most appropriate for the dye studied. Adsorption onto the Zn₂SnO₄ surface followed the Langmuir isotherm. The catalyst showed highly photocatalytic activity towards degradation of the dye, almost equal to that of the TiO₂-P25 Degussa photocatalyst. The results indicate that Zn₂SnO₄ could be employed for the removal of dyes from wastewaters.     

Preparation of cationic modified collagen extracted from leather wastes and their application in dye flocculation

A series of novel cationic flocculants are designed and synthesized successfully by grafting two monomers onto the collagen backbone, namely acrylamide (AM) and 2‐methacryloyloxyethyltrimethyl ammonium chloride (DMC). Apparently, these effective grafting modifications are well demonstrated by adopting FTIR and H¹ NMR measurements, which could be used to estimate grafting ratios of corresponding monomers approximately. Additionally, significant improvements in positive charge densities and amorphous aggregation structures are also definitely confirmed by Zeta and XRD measurements, respectively. Moreover, thermogravimetric analysis clearly proves the formation of cationic branched chain architectures, whose maximum thermal degradation temperature would significantly decrease with the introduction of AM. In addition, much more porous and rougher surface structures could be visibly observed after successful grafting modifications. Furthermore, when the feeding weight ratio between collagen and DMC is controlled at 1:3, or the equal amounts of AM and DMC are introduced meanwhile the mass ratio between collagen and mixed monomers (DMC + AM) is fixed at 1:4, the samples acquired could both perform the best in decolorizing the model wastewater containing methyl orange (MO) dyes in their groups, and hereby, a corresponding flocculation mechanism is also proposed based on the structural analysis of the formed flocs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45363.     

Use of indirect multiple linear regression for multicomponent dye analysis in a leather tanning bath

A spectrophotometric method for the simultaneous determination of dyes with spectral interaction in three-colour baths by use of multiple linear regression with indirect calibration has been developed. This method discretely allows the components of the dyeing bath to be quantified with errors of less than 3% and within 1–2 min of sampling. The method has been applied to monitor the dyeing of chromium-tanned bovine leather splits subjected to various retanning procedures.     

Improving the dyeing properties of textiles via utilization of redox systems. I. Dyeing of wool and wool/polyacrylic blend fabrics with acid dye

Dyeing of wool and wool/polyacrylic fabrics with an acid dye, namely, Kiton Scarlet 4 R, was carried out in absence or presence of different redox systems. The latter were based on sodium, potassium, or ammonium peroxodisulphate or potassium periodate as oxidant and glucose, sodium thiosulphate, potassium pyrosulphite or thiourea as reductant. Regardless of the redox system used, the colour strength was far greater in presence than in absence of the redox system. Except in case of potassium periodate/glucose redox system, increasing the oxidant concentration up to 0.03 mol/l caused significant enhancement in colour strength. The same was observed upon increasing the temperature from 30 to 60°C as well as the time from 10 to 40 minutes. It is postulated that presence of the redox system alters the mode of dye attachment to the substrate. Association of the dye with the substrate, wool in particular, seems to involve covalent bonding beside the usual salt-linkage. Hence the approach presented is advantageous in producing dyeings with much higher colour strength and dye fixation at relatively low temperature.