Dyeing treatments for protecting colour and colour fastness of green bamboo culms

The effects of various dyestuffs and treatment conditions on the epidermis colour of ma bamboo (Dendrocalamus latiflorus), moso bamboo (Phyllostachys pubescens), and makino bamboo (P. makinoi) were examined to determine the most appropriate dyeing material and approach for endowing bamboo culms with a fascinating green colour without removal of their epidermis. Experimental results revealed that excellent green colour was obtained when the three species of bamboo culms were treated with 0.25% basic dyes in an 80 °C water bath for 30 min (a* values of −19.6, −15.4, and −16.0, respectively). Moreover, alkali pretreatment, though contributing to dyeing effectiveness, yielded bamboo culms with dim surface lightness of low L* values. Dye makino bamboo culms without colour fixation post-treatment changed from green to light green after indoor exposure for 1 year, exhibiting unstable indoor colour fastness. In contrast, colour fixation post-treatment was found to improve colour fastness of bamboo culms; in particular, treatment with 1% glacial acetic acid or 3% tannic acid achieved more uniform dyeing effectiveness and better indoor fastness. By inhibiting discoloration, the natural beauty of bamboo culm can be preserved and its service life can be extended.     

Comparison of instrumental methods for assessing colour fastness. Part 1 — Change in colour

Different instrumental methods for assessing change in colour are described. A set of experimental results were used to test the performance of the various formulae and to illustrate the lack of agreement between them and visual results. Each method is based on a different colour-difference formulae. The differences between the formulae are illustrated by plotting constant AE contours for each of the formulae for various colour centres. The areas of colour where the formulae differ most from each other have been identified. The differences between the methods in some areas were very large, up to a factor of five in terms of ΔE, or two full grades of fastness.     

Instrumental methods for assessing colour fastness. Part 2 — Staining

In Part 1 of this paper, different fastness formulae for change in colour were compared. In the present report, the same methodology was used to compare different staining formulae. A set of experimental results was used to test the performance of various staining formulae. The constant grade contours for each formula were also calculated. Their patterns were compared and their differences were identified.     

The evaluation of procedures for dyeing silk with buckthorn and walloon oak on the basis of colour changes and fastness characteristics

In this study, silk fabric samples were dyed according to various procedures with buckthorn (Rhamnus petiolaris Boiss) and walloon oak (Quercus ithaburensis Decaisne) extracts. Reversed‐phase high‐performance liquid chromatography with diode‐array detection was utilised for the identification of dyes present in the dyed silk fabrics and the plant extracts. The extraction of dyes was carried out with a hydrochloric acid/methanol/water (2:1:1; v/v/v) mixture. The colour coordinates of the silk fabrics were measured, and the rubbing, wash and light fastness properties of the dyed silk materials were determined and are discussed.     

The colour and fastness of natural saffron

Cotton and wool fabrics have been dyed with the aqueous extract of saffron containing α-crocin as the main colorant species. The dyeings were carried out with and without metal salts as mordants. The wash and light fastness of the dyed fabrics was studied. The colour of the fabrics was investigated in terms of CIE L* C* H* values.     

Reactive dyeing of cationized cotton: Effects on the dyeing yield and the fastness properties

The cationization of cotton fibers is emerging as an effective tool for solving the environmental problems associated with the dyeing of cotton fabrics with anionic dyes. In this study, the dyeing performance of cationizing agents (Rucomor Bur, Kemifix REA, Optifix F, and Optifix RSL) were examined, and we found that this method had better results compared with normal or existing methods of reactive dyeing. The dye‐bath exhaustion and fixation were determined by the help of an ultraviolet–visible absorbance spectrophotometer on the basis of the maximum absorbance wavelength. Better fixation values were found with the cationizing process than with salty dyeing. The washing and rubbing fastness results were as the same as those of traditional dyeing. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

色牢度评价方法简介及比较

简介了ASTM D 4726《室外门窗组装用硬聚氯乙烯(PVC)挤出型材标准》中用于评价PVC型材耐候性的色牢度评价方法,并与EN 12608—2003《门窗用未增塑聚氯乙烯(PVC-U)型材分类、要求和试验方法》、GB/T 8814—2004《门、窗用未增塑聚氯乙烯(PVC-U)型材》、JG/T 263—2010《建筑门窗用未增塑聚氯乙烯彩色型材》、GB/T 3681—2000《塑料大气暴露试验方法》中耐候性评价方面的规定进行了对比,指出色牢度评价方法对于我国PVC型材行业制定同类标准具有很强的借鉴作用。     

PBT纤维染色牢度的研究

通过测试纤维的Lab值,比较纤维b值的不同,对比了PBT纤维与PET纤维的染色牢度,并进一步考察了空白PBT、PET纤维的被沾染的难易.结果显示：PBT纤维的色牢度好于PET纤维;PBT纤维比PET纤维容易被沾染;随着温度的升高,时间的延长,PBT纤维沾色越严重.     

Improvement of the standard method for assessing colour fastness to wet rubbing

Colour fastness to rubbing is evaluated by the degree of staining of a standard adjacent cotton cloth. However, some kinds of dye usually stain other textiles to a greater extent than cotton under wet conditions. In this work, rubbing fastness tests were carried out with various kinds of adjacent cloth in order to examine the factors affecting the wet rubbing fastness, and a more practical evaluation method using adjacent rubbing cloth was proposed. Dye transfer from the dyed fabric to the adjacent cloth depended on the affinity of the dyes for the fibre material of the dyed fabric and the adjacent cloth under wet conditions, in addition to the friction coefficient between the fabrics. A standard adjacent cloth should have a high staining property. The nylon staple cloth is preferred for fabrics dyed with vat, disperse, and acid dyes because it receives the most dye from rubbing with them.     

Effect of acylation on the dyeing and fastness properties of some azo dyes

The changes brought about by acetylation, benzoylation and terephthaloylation of some disperse dyes derived from 4–aminoazobenzene on the dyeing and fastness properties are described. Dyes substituted by benzoyl and terephthaloyl groups tended to have better light, wash and sublimation fastness on polyester. The dyes showed good build–up when these groups are coupled with an N–β–cyanoethyl group. Acylation of azo dyes resulted in poor substantivity and poor fastness properties on nylon 6.     

Colour and fastness of natural dyes: revival of traditional dyeing techniques

Cotton and wool fabrics were dyed with nine natural dyes obtained by aqueous extraction of the original plants/insect in an attempt to reconstruct traditional textile dyeing recipes, to optimise the methodology at all stages, i.e. extraction, mordanting and dyeing, and to standardise it. Cochineal, madder, alkanna, henna, brazilwood, red sandalwood, safflower, indigo and logwood were used for the dyeings, which were carried out directly and after mordanting of the textile material. A variety of mordants, namely, aluminium potassium sulphate, potassium dichromate, copper sulphate, zinc chloride, iron(iii ) chloride, iron(ii ) sulphate and tin chloride, is anticipated to meet both early and recent requirements and options. The dyeings were evaluated through colour measurements and standard wash, light and rub fastness tests. Generally, the mordanting process known for many centuries and connected with the textile dyeing resulted in an improvement in dye absorption and fastness properties mainly for the cotton samples, as is concluded from the tests and measurement assessments.     

Substituent effects on the colour,dyeing and fastness properties of 4-phenylazo-1-naphthylamines and of 2-acetylamino-5-methoxy-4-N-ß-cyanoethyl-N-ß-hydroxyethylaminoazobenzene

The synthesis of a series of blue disperse dyes obtained by diazotisation of substituted anilines and coupling with 2-acetylamino-5-methoxy-4-N-ß-cyanoethyl-N-ß-hydroxyethylaniline and to N-ß-hydroxyethyl-1-naphthylamine is described. Substituent effects on the colour of the dyes is discussed, with particular respect to analogous dyes derived from 4-N-ß-cyanoethyl-N-ß-hydroxythylaniline. Some dyes from trisubstituted anilines as diazo component colour polyester in deep blue shades of generally good fastness properties.     

Substituent effects on the colour,dyeing and fastness properties of 4-N-β-cyanoethyl-N- β-hydroxyethylaminoazobenzenes part I—monosubstituted derivatives

Data on a series of 40 monosubstituted derivatives of 4-N-β-hydroxyethyl-N-β- cyanoethylaminoazobenzene are reported. Structure-property relationships with respect to electronic spectra of the dyes, coloration and fastness properties on cellulose secondary acetate and polyester fibres are investigated. Reasons for the anomalous properties of the 2′-nitro derivative in exhibiting low lightfastness on synthetic polymer fibres are presented. The coloration of polyester fibres is additionally assessed in terms of data derived from tristimulus values of dyed fibres, and the effect of substituents on such data is discussed.     

Substituent effects on the colour,dyeing and fastness properties of 4-N-β-cyanoethyl-N-β-hydroxyethylaminoazobenzenes Part II—disubstituted derivatives

Dyeing and fastness properties on cellulose secondary acetate and polyester fibres of a series of 2′-substituted-4′-nitro, 4′-substituted-2′-nitro and 2′,6′-disubstituted-4-N-β-cyanoethyl-N-β-hydroxyethylaminoazobenzenes are reported. All dyes gave good coloration, with the exception of those containing the methylsulphonyl group, which had poor substantivity for polyester. Electronic spectra data of all dyes are reported; considerable steric hindrance was apparent with certain types of 2′,6′ disubstitution. Data derived from tristimulus values of dyed polyester showed the degree of 'off-tone' build up is greater with red dyes, than with orange and yellow dyes. The presence of a 2′-nitro group leads to poor lightfastness.     

Novel azo dyes derived from phthalimide. Part 2: Dyeing properties and colour fastness on polyester fibres†

The coloration and fastness properties of 18 carbocyclic monoazo disperse dyes bearing a phthalimide ring fused to the aromatic ring of their diazo components have been investigated. In each case, the phthalimidyl nitrogen atom was substituted with either a butyl, sec‐butyl or isopropyl group, while the adjoined phenyl ring bore a substitution pattern typical of commercial colorants. Dye uptake and build‐up onto both conventional and microfibre polyester through exhaustion dyeing were examined: while the expected tendency of greater exhaustion on microfibre was noted, there were few clear trends with respect to dye structure. The nature of the N‐alkyl group made no consistent difference to dye uptake. Attempts to explain the observed percentage exhaustion values by mapping them to calculated partition coefficient or solubility parameter values were unsuccessful. Wash fastness tended to be best for blue dicyano‐substituted derivatives, which may be as a result in part of these substituents promoting hydrolysis of the adjacent phthalimide ring to give more soluble phthalate species. In contrast, the dicyano dyes had relatively poor photostability compared with their unsubstituted analogues.     

Prediction of residual colour in reactive dyeing effluent

In this study, the absorbance of the three-dye mixture effluent from reactive dyeing has been used to predict the residual colour value of the dyeing effluent. The colour values of the dyeing effluent have been predicted in terms of ADMI colour values. The prediction accuracy was found to be satisfactory when some mathematical approaches, such as linear and non-linear regression, were used.