Non-isothermal dyeing of wool

Kinetic models of the dyeing process are reviewed and diffusion of dye into the fibre is identified as the rate-determining step in most dyeing processes. A simpler approach to defining a linear exhaustion profile of acid dyes on wool fibres is proposed that takes into account non-isothermal kinetic models and analyses their possibilities of use. In this endeavour a novel dyeing rate constant is defined that appears to be characteristic of a particular dye class.     

The effect of reactive dyes on damage in wool dyeing

This paper demonstrates that reactive dyes exert a significant fibre–protective effect when dyeing wool fabric; this effect may be measured, in a reproducible manner, using the wet–burst strength test. The effect of dyebath pH, dye concentration, dyebath temperature and dyeing time on wool can thus be evaluated. The magnitude of the above protective effect has been compared with that achieved using commercially available fibre–protective agents. It is concluded that reactive dyes are significantly more effective than the latter agents when employed in medium to full depths. It is proposed that the unusual protective effect afforded by reactive dyes is related to the following factors. Reactive dyes readily react with sulphur nucleophiles, thus inhibiting thiol–disulphide interchange reactions and thereby significantly interfering with the level of set produced in a boiling dyebath. Reactive dyes react preferentially with non–keratinous proteins in the intercellular cement and the endocuticle thus reducing their tendency to hydrolyse and to partially dissolve in the hot aqueous dyebath.     

The effect of liposome on dyeing mohair/wool blends

The aim of this study was to examine the use of liposome in the dyeing of wool and mohair fibres with acid dyestuffs. Soybean lecithin and cholesterol were used to form the liposome membrane utilised in the dyebath. Liposome production was performed according to the thin lipid layer method (Bangham Method) using a rotary evaporator. Two different forms of liposome were used for dyeing wool and mohair fibres. In its first form, liposome was utilised as an auxiliary agent, where it was added to a conventional dyebath at the beginning of the process. In its second form, dyes were encapsulated with liposome and then used in dyeing. The effects of these two different forms of liposome were compared with conventional dyeing. Dyeing was carried out at depths of shade of 0.5%, 1.0% and 2.0% using three different concentrations of liposome (0.33%, 0.66% and 1.33%). An analysis of K/S values, fastness to washing, and the alkali solubility of fibres was conducted. The fibre samples dyed in the presence of liposome exhibited very good fastness to light (grade 8). The wash fastness test results of the liposomal‐dyed samples were significantly better (grade 4‐5) than for those samples which were conventionally dyed. In the presence of liposome, the tensile strength of fibres was 20 gf, whereas it was 11 gf without liposomes.     

Plasma modification on wool fibre: effect on the dyeing properties

The dyeing properties of wool fibre treated with low-temperature plasma (LTP) were investigated kinetically and thermodynamically. Three non-polymerising gases, namely oxygen, nitrogen and a 25% hydrogen/75% nitrogen gas mixture, were used for the LTP treatment. It was found that the dyeing rate, dye uptake, standard affinity, heat of dyeing, entropy of dyeing and activation energy of diffusion were improved after the treatment.     

The distribution of some fluorescent anionic surfactants applied to wool

The distribution of surfactants in the different regions of the wool fibre has been studied by applying several novel fluorescent surfactants to wool under various conditions and studying sections of the treated fibres under the fluorescence microscope. The intercellular and cell remnant regions appear to be the preferred locations for these surfactants in the wool fibre, but various distributions can be obtained, depending on the length of the hydrocarbon chain of the surfactant and the conditions under which it is applied. The similarities in surface activity, sorption and extraction behaviour of the more typical surfactant sodium dodecyl sulphate and some of the fluorescent surfactants suggest that the former surfactant may have a similar distribution between the different regions of wool.     

表面活性剂在纺织染整中的应用

按照表面活性剂的离子类型，分别讨论了阳离子型、阴离子型、非离子型和两性表面活性剂，以及其他新型表面活性剂在纺织染整中的应用。重点介绍了绿色环保型表面活性剂，并对表面活性剂在纺织染整中的发展方向予以展望。     

Enzymes as auxiliary agents in wool dyeing

The action of three enzymes has been comparatively studied when used as auxiliary agents in dyebath. The absorption rate of the dye, the colour differences between wool dyed with and without enzymes and the colour fastness were determined. The action of enzymes consists of increasing dye absorption and also seems to produce a better diffusion of the dye into the fibre. The use of the enzymes in wool dyeing offers the possibility of dyeing under mild temperature conditions.     

A new kinetic model for wool dyeing

Previous kinetic models of the dyeing process are reviewed in an attempt to describe the exhaustion profile of acid dyes on wool fibres. A new kinetic model is proposed that describes the dye uptake throughout the whole kinetic period, and that takes into account the amount of dye and acid supplied at the beginning of dyeing. The equation is used to achieve isoreactive dyeing by calculating the amount of dye to add during the dyeing process.     

Metal ion effect on dyeing of wool fabric with catechu

Wool fabric was dyed with catechu by two different process sequences using various metal sulphates as mordant. The dyeing behaviour has been assessed by measuring K/S values and different fastness properties. The effect of different metal ions have been studied with respect to their influence on colour and fastness properties. The mechanism of mordant interaction with the fibre has been briefly considered.     

Absorption of betaines by wool and its effect on dyeing

This paper reports a study of betaine absorption by wool, the main parameters affecting it and its influence on dyeing with acid dyes. An attempt to establish the types of interaction between fibre, betaine and dye is discussed. The influence of pretreatment with various betaines on the dye distribution (whether the dye is superficially deposited or has diffused into the fibre) throughout the whole dyeing process is also studied.     

Influence of ionic surfactants on the hydrogen peroxide bleaching of wool fabric

We have studied the influence of ionic surfactants on the bleaching of wool with hydrogen peroxide under acidic and alkaline conditions, comparing anionic sodium alkyl sulphates with eight, 12 and 16 carbon atoms and the cationic surfactant dodecyltrimethylammonium bromide (DTAB). Addition of ionic surfactants to both acidic and alkaline bleaching baths improved the whiteness of wool, especially at above 0.01 mol/l. Anionic surfactants prevented fibre damage during bleaching of wool, whereas DTAB accelerated it. The fibre damage decreased with increasing concentration of alkyl sulphates and with increasing length of hydrocarbon chain.     

Mechanistic investigations on the action of levelling agents in reactive wool dyeing

Although levelling agents for reactive dyes have been on the market for more than twenty years, there still remains some uncertainty as to their mode of action. Therefore an investigation has been carried out, using Albegal B as a typical levelling agent and reactive dyes from the Lanasol range. There are three mechanisms proposed to describe how auxiliaries such as Albegal B can act to overcome tip/root unlevelness when dyeing wool fibres: a dye complex mechanism, a surface mechanism and a fibre mechanism. These are discussed in the light of the experimental results.     

洗毛及染色综合废水处理技术

介绍了利用物化法对洗毛废水预处理后再与染色废水合并处理的实际情况和工程治理效果,解决了该污水处理中的几个关键问题。结果表明：洗毛废水经预处理后,CODcr、SS去除率可分别达90%、95%以上,综合废水经水解酸化一好氧及物化处理后,CODcr可下降为180mg／L,色度可降为4。     

姜黄素酰化改性提高其对羊毛织物的染色性

对姜黄素进行酰化改性,将改性前后姜黄素上染羊毛织物,测定日晒牢度、皂洗牢度、摩擦牢度及匀染性。结果表明,在无助剂与有助剂条件下,酰化姜黄素比姜黄素染色品的日晒牢度、皂洗牢度、摩擦牢度及匀染性均提高0.5～3级。     

Reactive dyeing systems for wool fibres based on hetero-bifunctional reactive dyes. Part 2: Investigation of dyeing properties during the dyeing cycle

The dyeing behaviour during the dyeing cycle of a Sumifix Supra dye and some other commercial reactive dyes under various dyebath pH conditions was investigated. Studies of the dyeing of wool serge fabric indicated that the diffusion properties of hetero-bifunctional Sumifix Supra dyes generally lie between those of b-sulphatoethylsulphone (Remazol dyes) and monochlorotriazine (Procion H dyes).     

The use of ultraviolet radiation in an adsorbable organohalogen-free print preparation for wool and in wool dyeing: the Siroflash process

German legislation controlling the discharge of adsorbable organohalogens (AOX) in process effluents has focused attention on the need for environmentally acceptable alternatives to chlorination as a prepare-for-print (PFP) treatment for wool. The Siroflash process is a novel AOX-free approach which involves continuous UV irradiation of dry wool fabric, followed by conventional wet oxidation using hydrogen peroxide or permonosulphuric acid. Although permonosulphuric acid or peroxide treatments alone are ineffective as a PFP, the colour yields of prints on Siroflash-treated fabric are similar to those on chlorinated wool. The synergistic interaction between UV exposure and wet oxidation results in high levels of cystine oxidation, cuticle damage and loss of soluble protein, all of which are highly specific to irradiated surface fibres. UV irradiation of wool can significantly increase dyeing colour yields. The use of 1:1 metal-complex dyes is particularly effective, and a 3% o. w. f. dyeing on UV-treated fabric can produce a better depth of shade than a 5% dyeing on untreated fabric.     

Novel approach for antisetting of wool fabrics during dyeing

New antisetting agents are proposed for wool fabrics during dyeing at the boil, viz., dithiodipropanoic acid ( DTDPA) and dithiosalicylic acid (DTSA). DTDPA was found to be better than DTSA in the protection of wool during dyeing. The effect of the addition of these reagents to the dyeing bath of wool on some of its inherent mechanical properties was assessed. A proposed mechanism of reaction between the aforementioned dithiols and wool keratin is reported.