adjusting the amount of air during conventional reduction clearing

In this study we investigate the influences of air content in the sealed reduction-clearing equipment, liquor ratio, sodium dithionite, and sodium carbonate concentrations of an alkaline reduction-clearing bath on wash fastness properties of poly(lactic acid) fabrics dyed with alkali-sensitive and alkali-stable disperse dyes. Lower air content in the sealed reduction-clearing equipment and a greater amount of sodium dithionite present in the clearing bath leads to better wash fastness values. The reduction clearing with a higher liquor ratio resulted in higher wash fastness levels due to the lower amount of air present in the sealed reduction-clearing equipment. The extent of the improvement on wash fastness properties of dyed poly(lactic acid) fabrics depends on the combination of alkali sensitivity of the disperse dye, sodium dithionite concentration, liquor ratio, and air ratio in the clearing equipment. No polymer degradation occurred during the alkaline reduction-clearing process. Poly(lactic acid) fabrics, after reduction-clearing processes, exhibited approximately similar performance for each dyeing compared to the non-cleared control sample, leading to a slight decrease on color yield (f(k)), slightly higher chroma (C*), higher lightness (L*), and therefore brighter appearance without significant shade change

conditions

This study has been conducted to examine the influence of different clearing treatments, following dyeing using different clearing agents under acidic and alkaline pH conditions, on the colour fastness and colour properties of poly(lactic acid) fabrics dyed with alkali-sensitive and alkali-stable disperse dyes. Wet-fastness properties of poly(lactic acid) fibres dyed with both alkali-sensitive and alkali-stable disperse dyes were improved to the commercially acceptable levels with a clearing treament at 60 degrees C for 15 minutes using the right combination of the chemistry of the dye, clearing agent type and pH condition (pH 5 and pH 10.7) of the applied clearing bath. Overall, successful clearing treatments, judged by high wet fastness results, exhibited approximately similar performances for each dyeing compared to a non-cleared control sample. These clearing treatments led to a very slight decrease in colour yield (f(k)), slightly higher chroma (C*), higher lightness (L*) and therefore brighter appearance without significant shade change. No poly(lactic acid) polymer degradation occurred during clearing whichever clearing agent is used, and whether the conditions are acidic or alkaline

Overview of Poly(lactic acid) (PLA) Fibre

Poly(lactic acid) (PLA), the first melt-processable synthetic fibre produced from annually renewable resources, combines ecological advantages with excellent performance in textiles. PLA successfully bridges the gap between synthetic and natural fibres and finds a wide range of uses, from medical and pharmaceutical applications to environmentally benign film and fibres for packaging, houseware, and clothing. Ease of melt processing, unique property spectrum, renewable source origin, and ease of composting and recycling at the end of its useful life has led to PLA fibres finding growing interest and acceptance over a range of commercial textile sectors. Our review of poly(lactic acid) (PLA) fibre is divided into two parts. Part I of this review gives information about production, properties, performance, environmental impact, and enduse applications of PLA fibres. The aim of Part II is to review the wet processing (pretreatment, dyeing, clearing, subsequent finishing treatments, washing, etc.) of PLA fibre and its effects on the fibre. These were accomplished through a broad literature survey, including recent research and development in the area

Bleaching of Hemp (Cannabis Sativa L.) Fibers with Peracetic Acid for Textiles Industry Purposes

Hemp plant exhibits various eco-friendly properties and hemp fiber processing does not cause environmental damage, however, it is known that most chemical operations have a risk to interrupt a sustainable production. As stated in several studies, peracetic acid is an important environmental friendly bleaching agent when compared to its conventional competitors. In this study, hemp fabric was bleached with peracetic acid with exhaustion and padding methods. The effects of temperature, pH, process time, concentration on whiteness values were determined. The influences of bleaching processes were investigated via instrumental and imaging methods. Physical properties of the treated fibers were also tested. Besides peracetic acid, hydrogen peroxide bleaching was carried out for comparison. COD values of bleaching effluents were analyzed for selected samples. Higher whiteness values were obtained with exhaustion bleachings than pad-batch bleachings. Quite high whiteness values (up to 68.13 Stensby whiteness index) attained in peracetic acid without significant fiber damage. © 2018, The Korean Fiber Society and Springer Science+Business Media B.V., part of Springer Nature

Barwienie włókien pokrzywy (Urtica Dioica L.) barwnikiem naturalnym kraplak (Rubia Tinctorum L.) przy użyciu ultradźwięków i mikrofal

In this study, eco-friendly 100% nettle bast bio-fibre fabric was dyed with eco-friendly natural dye, madder (Rubia tinctorum L.), using alternative dyeing methods such as ultrasound and microwave energy. Dyeings were performed with conventional-exhaustion, ultrasound and microwave methods using green tea and alum as mordants. The colorimetric, colour fastness properties and FTIR-ATR spectra of the nettle-biofibres dyed were investigated. Although the colour strengths of the microwave and ultrasound energy-aided dyeings were not as high as in conventional dyeings, the usage of microwave-energy in dyeing is important in terms of shortening the process time. All dyed nettle fabrics exhibited very high and commercially acceptable wash, dry-rub, alkaline-perspiration, acidic-perspiration and water fastness properties. Overall the conventional and ultrasound dyeing methods caused slightly higher light fastness than the microwave assisted dyeing method.W pracy wykonane z włókien pokrzywy dzianiny barwiono ekologicznym naturalnym barwnikiem kraplak (Rubia tinctorum L.) przy użyciu ultradźwięków i mikrofal. Barwienie przeprowadzono stosując jako zaprawę farbiarską zieloną herbatę i ałun. Zbadano właściwości kolorymetryczne, trwałości koloru i widma FTIR-ATR wybarwionych włókien. Stwierdzono, że mimo, iż efekt barwienia przy użyciu mikrofal i ultradźwięków nie był tak silny, jak w przypadku tradycyjnego barwienia, to użycie mikrofalal wpływa na skrócenie czasu procesu. Wszystkie barwione wyroby wykazały bardzo wysokie i dopuszczalne w handlu trwałości na: pranie, pocieranie na sucho, potliwość kwaśną i alkaliczną oraz trwałość na wodę. Stwierdzono, że konwencjonalne i ultradźwiękowe metody barwienia powodowały nieco wyższą odporność na światło, niż barwienie przy użyciu mikrofal

Synthetic Fiber Dyeing with New Pyrazole Disperse Dyes and Their Colorimetric and Fastness Properties

A series of disazo pyrazole disperse dyes were synthesized and reported at our previous work. These 8 synthesized disazo pyrazole disperse dyes (3a-3h) were applied to poly(lactic acid) (PLA), poly(ethylene terephthalate) (PET), and polyamide 6.6 fibers. Their colorimetric and color fastness properties were investigated. All studied fibers dyed with these synthesized dyes exhibited yellow-red shades. 3c (p-Cl), 3e (m-Cl), and 3h (o-Cl) disazo disperse dyes, having auxochrome -Cl, led to the lowest color yield values for all three studied fibers. The same dyes resulted in higher color strength with darker shades on the PET and PLA fabrics in comparison PA 6.6 fabrics. 3a (p-NO2), 3b (p-OCH3), 3d (m-NO2), 3f (o-NO2), and 3g (o-OCH3) disazo disperse dyes can be recommended for PLA and PET dyeing from the color point of view leading to medium to heavy depth of shades. The wash, alkaline and acidic perspiration, dry and wet rub, water and sea water fastness levels of PLA, PET, and PA 6.6 samples dyed with 3a-3h dyes were generally quite high and in the commercially acceptable range with few exceptions. Dyed PLA fabrics displayed better sublimation fastness levels than dyed PET and PA 6.6 fabrics. Synthesized disperse dyes resulted in high light fastness performance on especially PET and PLA fibers. Light fastness level was better for dyed PET samples by comparison with dyed PLA and PA 6.6 fabrics. © 2018, The Korean Fiber Society and Springer Science+Business Media B.V., part of Springer Nature.Firat University Scientific Research Projects Management Unit: 2012FBE035This study is sponsored and supported by Pamukkale University Scientific Research Project Coordination Unit PAUBAP by the project number of 2012FBE035

solutions by ozonation

In this study, the effects of ozonation, ozonation with ultrasonic bath and ozonation with ultrasonic homogeniser processes on colour and chemical oxygen demand removal properties of disperse (CI Disperse Red 60, CI Disperse Blue 337) and reactive (CI Reactive Blue 171 and CI Reactive Blue 19) dyebath solutions with and without dyeing auxiliaries were investigated. Chemical oxygen demand (in mg/l) and colour (in Hazen) measurements of the studied dyebath solutions were determined. The ozonation process caused simultaneous chemical oxygen demand removal during decolorisation. However, the improvement in chemical oxygen demand reduction was less than of that on decolorisation. The application of the combination of ozonation with ultrasonic homogeniser is the most efficient process and creates a great time advantage over the other process types studied (ozonation alone and ozonation with ultrasonic bath) to reach the same colour and levels of chemical oxygen demand removal

developments

In textile industry, supercritical carbon dioxide (scCO2), possessing liquid-like densities, mostly find an application on textile dyeing processes such as providing hydrophobic dyes an advantage on dissolving. Their gas-like low viscosities and diffusion properties can result in shorter dyeing periods in comparison with the conventional water dyeing process. Supercritical carbon dioxide dyeing is an anhydrous dyeing and this process comprises the usage of less energy and chemicals when compared to conventional water dyeing processes leading to a potential of up to 50% lower operation costs. The advantages of supercritical carbon dioxide dyeing method especially on synthetic fiber fabrics hearten leading textile companies to alter their dyeing method to this privileged waterless dyeing technology. Supercritical carbon dioxide (scCO2) waterless dyeing is widely known and applied green method for sustainable and eco-friendly textile industry. However, not only the dyeing but also scouring, desizing and different finishing applications take the advantage of supercritical carbon dioxide (scCO2). In this review, not only the principle, advantages and disadvantages of dyeing in supercritical carbon dioxide but also recent developments of scCO2 usage in different textile processing steps such as scouring, desizing and finishing are explained and commercial developments are stated and summed up

Porównanie zmiękczania tkanin PLA i PET z zastosowaniem systemu KES-FB

We examined and compared low-stress mechanical properties, such as tensile, shear, bending, compression, and surface properties, measured by the Kawabata Evaluation System for Fabrics (KES-FB), of polyethylene terephthalate (PET) and poly(lactic acid) (PLA) fabrics before and after softening with commercial softeners. The bending and shear properties of both fabrics were influenced by the chemical nature of the softening agents and the emulsion type used in the softener. In contrast, the ionicity and hydrophobicity of the softener appeared to have little or no effect on bending and shear properties of both fabrics. There is no clear trend showing that the LT, RT, MMD, MIU, LC, and RC values of both fabrics were influenced by any of the following properties of the softeners: the chemical nature, emulsion type, ionicity, or hydrophobicity. The best performing softener for both fabrics was a slightly cationic hydrophobic aminofunctional polydimethylsiloxane micro-emulsion softener. Overall, all softened PLA fabrics exhibited lower bending rigidity, tensile linearity, and tensile resilience as well as higher tensile energy, extensibility, geometrical roughness, mean deviation of friction, and compression energy values than all softened PET fabrics, leading to a softer, fuller, and fluffier but rougher fabric handle.Badano i porównano właściwości mechaniczne przy małych naprężeniach, takie jak: wytrzymałość na zrywanie, ścinanie, zginanie, ściskanie, jak również właściwości powierzchniowe zmierzone za pomocą systemu Kawabata KES-FB. Stwierdzono, że na właściwości zginające i ścinające tkanin wpływa chemiczny skład zmiękczaczy i emulsji. Natomiast właściwości jonowe i hydrofobowe maja minimalny lub zerowy wpływ na właściwości zginania i ścinania obydwu rodzajów tkanin. W pozostałych przypadkach nie stwierdzono występowania wyraźnie określonych zależności pomiędzy parametrami tkanin a rodzajem zmiękczacza. Ogólnie rzecz biorąc, wszystkie zmiękczane tkaniny PLA wykazywały niższą sztywność zginania, liniowość przebiegów wytrzymałościowych na rozciąganie i odprężność, jak również większą energię zrywu, rozciągliwość, średnie odchylenie tarcia i energię ściskania w porównaniu do tkanin PET

Fabrics After Different Finishing Steps

We have studied a mathematical model to compare the handle of polylactic acid (PLA) and polyethylene terephthalate (PET) fabrics throughout finishing steps. Mechanical and surface properties at low stress of PLA and PET fabrics and the effects of different finishing treatments on these properties are investigated. The KES-FB (Kawabata Evaluation System for Fabrics) is used for the measurements of low stress tensile, shear, bending, compression and surface properties. There is no standard method to determine the total handle value for summer knitted fabrics. Therefore a mathematical method i.e. the Weighted Euclidean Distance method was used to indirect determination of total handle value from the KES-system parameters. The results reveal that the mechanical and surface properties as well as handle of PLA and PET fabrics change significantly after different finishing stages. The difference between handle of PLA and PET fabrics has been significantly reduced after dyeing, drying, heat setting and softening processes