The Use of Disperse Dyes for Dyeing of Recycled Polyethylene Terephthalate Fibres

Recycled polyethylene terephthalate (r-PET) is a widely recycled plastic employed for new textile production in the world. It reduces environmental impact and lowers cost of the production. For the traditional dyeing of polyethylene terephthalate (PET), commercial disperse dyes are generally used. In presented research the recycled r-PET fibres 6 den dyeing with disperse dyes Itosperse: Red, Blue and Yellow (concentration 3 Wt. %) were examined and the influence of the intensifier of a salicylic acid (with concentration of 4 - 10 g/L) in dye bath was investigated. The colour properties of dyed samples and colour fastness to washing were tested. It is concluded that the presence of the intensifier of salicylic acid improves dyeing results, but the optimal concentration differs for each dye. Colour fastness test to washing of the blue dyed samples showed the insignificant changes of colour parameters. In some cases the change of shade in presence of salicylic acid was observed.

Colour Fastness to Various Agents and Dynamic Mechanical Characteristics of Biocomposite Filaments and 3D Printed Samples

The aim of the study was to analyse the colour fastness of 3D printed samples that could be used as decorative or household items. Such items are often fabricated with 3D printing. The colour of filaments affects not only the mechanical properties, but also the appearance and user satisfaction. Samples of biocomposite filaments (PLA and PLA with added wood and hemp fibres) were used. First, the morphological properties of the filaments and 3D printed samples were analysed and then, the colour fastness against different agents was tested (water, oil, detergent, light and elevated temperature). Finally, the dynamic mechanical properties of the filaments and 3D printed samples were determined. The differences in the morphology of the filaments and 3D printed samples were identified with SEM analysis. The most obvious differences were observed in the samples with wood fibres. All printed samples showed good resistance to water and detergents, but poorer resistance to oil. The sample printed with filaments with added wood fibres showed the lowest colour fastness against light and elevated temperatures. Compared to the filaments, the glass transition of the printed samples increased, while their stiffness decreased significantly. The lowest elasticity was observed in the samples with wood fibres. The filaments to which hemp fibres were added showed the reinforcement effect. Without the influence on their elasticity, the printed samples can be safely used between 60 and 65 °C.

Improving Dyeing Properties of Cotton Fabrics to Natural Dyes with Cellulose Nanocrystals (CNCs) [Mejora de las propiedades de teñido de telas de algodón a tintes naturales con nanocristales de celulosa (CNC)]

Natural dyes can make less environmental problems associated with manufactured colouring agents and textile dyeing. But, the natural dyes fixing process was used chemicals called mordant. The most of times mordants were used metallic salts and metal salts mordants were not environmentally friendly. Therefore, remove the disadvantage associated with natural colorants and the use of nanoparticles. In this research, cotton fabric was treated with the nanoparticle of cellulose nanocrystals (CNCs) as mordant. The cellulose nanocrystals extraction process was done by using Whatman filter paper. The cellulose nanocrystals obtained will be further analyzed and characterized by using selected tools such as Particle size analysis and Fourier-transform infrared (FTIR) spectroscopy. The cotton fabrics mordanting processes were done by two types of pre-mordanting and post-mordanting methods. The three natural ingredients of Mangifera indica (Mango) leaves, Tectona grandis (Teak) leaves and Lannea coromandelica (Indian ash tree) leaves were used to extract the natural dyes using with aqueous extraction method. The extracts from dyeing processes were carried out after and before mordanting processes. The dyed sample from colour fastness to light, washing, and crocking were assessed according to standard methods. The cellulose nanocrystals gave very good colour fastness to light, wash, and rubbing when dyed with all three dye extractions. In the present study, innovative mordant of cellulose nanocrystals and natural dyeing with three natural dye extractions have been shown to give good dyeing results with cotton fabric.

INFLUENCE OF “COLD” DYEING TECHNOLOGY ON FABRIC CHARACTERISTICS

"The current work presents a comparative analysis of the colour fastness against repeated washing of cellulose-containing fabrics dyed by “cold” and classical technologies, using different types of active dyes, at various concentrations in the dye bath. Mathematical models have been proposed to describe the determined dependencies. The study uses Reakol dyes – a trademark of bifunctional active dyes manufactured by Khimtex (Kherson), which can be used for “cold” resource-saving dying technologies. The studied active dyes are characterized by a wide colour spectrum, good solubility, colour purity and high resistance of colours to wet treatments. The study has found that increasing the concentration of Reakol dyes in the dye bath, from 10 to 30 g/L, as a rule, had no significant influence on the colour fastness of fabrics to repeated washing. However, the colour intensity on the fibre significantly rose when increasing the dye concentration in the dye bath. It was determined that, when using the “cold” dyeing technology, sweeping changes in the general colour contrast and residual concentration of the dye on the fibre occurred after the first 5 washes. The changes in these indicators somewhat stabilized after the following 10-20 washes. However, a proportional relationship between the variation in the general colour contrast and a decrease in the dye colour intensity on the fibre after the corresponding number of washes of the studied fabrics was not detected. "

INVERSTIGATION OF RUBIA CORDIFLORIA (INDIAN MADDER) DYE ON SILK FABRIC

Synthetic dyes release huge amount of waste and uniform colourants lead to health hazard. It also disturbing the ecobalance of the nature. Natural dyes are mostly derived from plants, invertebrates, or minerals. The most of the natural dyes are vegetable dyes from plant sources-roots, berries, bark, leaves, and wood—and other organic sources such as fungi and lichens. Natural dyes exhibit good biodegradability and are more compatible with the environment. In spite of their inferior fastness, natural dyes are more acceptable to environmentally conscious people around the world. The present study deals with the natural dyes extracted from Rubia Cordifloria. The extracted dye used to dye selected silk fabric and myrobalan mordant used for dye ability, fastness properties, absorbency test. Two shades with different concentration have been developed. Absorbency properties of the dyes extracted from madder and sinking test was determined. The colour fastness through washing and rubbing (Wet and Dry) was an excellent satisfaction in both different concentrations.

A preliminary study of printed electronics through flexography impression on flexible substrates

The work is framed within Printed Electronics, an emerging technology for the manufacture of electronic products. Among the different printing methods, the roll-to-roll flexography technique is used because it allows continuous manufacturing and high productivity at low cost. Apart from the process parameters, the ink and the substrate properties are some of the variables associated with the flexographic printing. Specifically, this study investigates the ink penetration, the print uniformity, the adhesion, the fastness, and the electrical behaviour of the same conductive silver ink printed on different flexible substrates through the flexography process. In addition to polymeric and siliconized paper substrates, which are typical used in printed electronics, two substrates were also chosen for the study: woven and nonwoven fabric. Optical, scanning electronic microscope (SEM), 4-point Kelvin and colour fastness to wash and rubbing analyses have been performed. The results concluded that, regarding the conductivity behaviour, porous substrates like textiles and nonwoven fabrics without pre and post treatments do not present acceptable results, whereas polymers or silicone papers do. Nevertheless, woven and nonwoven fabrics are a suitable early option regarding colour fastness to wash instead of thin polymeric and paper substrates that tear at the wash machine. A solution for an optimal printing on textiles would be the surface substrates pre-treatment by applying different chemical compounds that increase the adhesion of the ink on the fabric

To study natural herbal dyes on cotton fabric to improving the colour fastness and absorbency performance

Nowadays, all consumers are more preference for the natural herbal textile dye garment products. These herbal dye cloths are more eco friendly products. It is give non-toxic, chemical free product and this does not harmful environment nature. Herbal textile is dyed entirely with herbal extraction, without using any sort of chemical. The herbs used different from vegetable dyes as they are not only natural but also have medicinal value. These herbs are applied directly to the fabric with the help of natural ingredients, So that the medicinal value of the herbs can be kept intact, because synthetic dyes large amount of waste and unfixed colorants poses serious health hazard and are disturbing the eco balance of nature. Environmental issues in the production and application of synthetic dyes once again revived consumer interest in natural dyes. In this research work we have applied natural herbal dyes on cotton fabrics surface. This work has used natural herbal dyes like turmeric, aloe vera, neem, beetroot, pomegranate and onion. Edible gum and cow urine has used to improve in colour fastness and dye absorbency performance. This research main aims to give a new approach natural herbal dyes products will more used in textile sector. It will more help to reduce diseases problem skin allergies and skin infection.