Computational investigation on the flow characteristics in beam dyeing process

Abstract

Ensuring uniform addition of coloring material to the fabric is an essential requirement in the textile dyeing process. Beam dyeing machine consists of a special beam, the barrel of which is evenly perforated with holes. The dye liquor is forced into the fabric material through this beam. For uniform fabric coloring, an equal distribution of the dye liquor through the porous beam has to be ensured. The present methodology employs theoretical and computational fluid dynamics aspects of beam dyeing process to obtain better performance. The analysis of a beam with a single row of branches shows that nonuniformity increases with an increase in inlet mass flow. Further beam flow distribution with and without fabric are studied for different parameters, such as branch diameter, inlet mass flow rate, operating conditions, and flow reversal. The present results provide guidelines to improve the levelness of the dye distribution in the fabric material.     

筒子和经轴染色的液流分布及其匀染性

匀染性是评价染色质量的重要指标,筒子纱和经轴制备及其染色过程中的许多因素都将影响液流分布从而影响匀染性。为提高匀染效果,探讨了股线加捻和筒子纱卷装密度分布对匀染性的影响;染色经轴末端固定圈及边孔封闭圈的使用对染液轴向流动和液流均匀性的影响;经轴染色时,在低密度织物的外层使用低渗透系数材料包覆对液流分布对称性的影响。结果表明,在股线加捻过程中,通过调节卷绕角和偏转角可提高筒纱的染液渗透性,进而提高匀染性。恒定的络筒张力并不能得到密度均匀的筒纱,使筒纱从内到外卷装密度降低,有助于提高匀染性;卷装各层密度变化对     

Near-infrared green camouflage of cotton fabrics using vat dyes

In order to match the reflectance profile of the greenish leaf at NIR region, four commercially available vat dyes were used to dye cotton fabrics. The reflectance of dyed fabric and the transmittance of dye liquor in alcohol solution were measured by using U-4100 spectrometer with an integrating sphere. The effects of the combination dyeing, dyeing concentration (% owf) and fabric weaves on the reflectance were also studied. The results show that the reflectance of the combination dyeing is determined by one of the dyes whose reflectance curve emerges at longer wavelengths. Vat Blue 13 plays an important role in green camouflaging. When the dyeing concentration of vat blue 13 is 1–2% owf, the reflectance of the dyed fabric almost overlaps that of greenish leaf in red shift region (region A). Fabric weave has a little effect on the reflectance for the same dyeing program.     

新型低碱活性染料染色工艺研究

针对活性染料常规染棉织物工艺中纯碱用量过多的问题,采用新型的低碱活性染料对棉织物进行染色。分析了工艺参数如盐、碱及温度等对K/S值的影响,得到了低碱活性染料染棉织物较佳工艺:染料1%(owf)时,纯碱1.5g/L,元明粉70g/L,80℃固色40min,浴比1∶25;染料5%(owf)时,纯碱3g/L,元明粉80g/L,80℃固色60min,浴比1∶25。低碱活性染料染色所需纯碱用量少,仅为传统活性染料染色时纯碱用量的1/10左右,染色织物得色量高,且染色工艺简单。     

织物升温速率对活性染料轧-蒸无盐染色的影响

针对活性染料轧蒸染色固色率低的问题,通过测试湿织物热常数探究织物表面温度变化规律,分析了染液组成和带液率对织物热常数、升温速率及染色性能的影响,研究了织物升温速率对活性染料染色性能的影响。结果表明：添加硫酸钠能够促进织物升温,提高染色织物的K/S值和固色率,但不符合无盐染色的要求;增加带液率,湿织物导热系数和容积热容随之增大,而表面温度却呈现降低趋势;染料固色率与织物表面升温速率变化规律一致,说明提高织物升温速率有助于改善活性染料染色性能;降低织物带液率可提高升温速率,是实现无盐染色的有效途径。     

浅谈涤纶织物“鸡爪印”疵病的克服方法

简述涤纶织物高温高压染色，产生“鸡爪印”疵病的成因。解决该疵病的关键措施是，在染色前增加一次预定形，严格控制染色时布的运行速度，升降温速率，排液温度，尽量减少织物在染缸内的折迭状态。     

Reactive dyeing of a pretreated jute fabric using minimum application technology

Abstract

Grey jute fabrics were given pretreatment such as scouring which was followed by enzyme treatment. These pretreated jute fabrics were subsequently bleached with hydrogen peroxide. Dyeing of these bleached jute fabrics was carried out with four different classes of reactive dyes, namely cold- brand, hot-brand, vinyl sulphone and HE-brand reactive dyes, following the conventional exhaust method and pad-batch method, i.e. minimum application technology method. With respect to dyeing behaviour, it was found that dye uptake and wash fastness property of a dyed fabric produced by the pad-batch method is well comparable with that produced by the conventional exhaust method. Irrespective of the methods of dyeing, scoured–bleached and scoured–enzyme treated–bleached jute fabrics show better dye uptake and fastness property compared to grey-bleached fabrics. Weight loss and strength loss increase while bending length decreases with the increase in pretreatment stages. Enzyme treatment of a scoured jute fabric before bleaching produces the minimum bending length among all the samples. The pretreatment process is found to have some detrimental effect on the tensile properties of a jute fabric and as the number of pretreatment steps increases, the tenacity of the fabric decreases. Reactive dyeing of pretreated jute fabrics further reduces their tensile strength by around 10% irrespective of the method of dyeing and the pretreatment process. So, minimum application technology can be well adopted for dyeing of a jute fabric with reactive dyes. The process is simple, cost effective as it utilises dye to its maximum extent, requires minimum energy and is suitable for use in cottage and small-scale industries.     

Effect of Lipase Pretreatment on the Dyeability of Wool Fabric

Abstract

The effect of lipase pretreatment on the dyeability of wool fabric with reactive dyes is thoroughly investigated. Two enzymes are applied, lipase type II and lipolase 100 L, type EX. The effect of treatment conditions such as temperature, time, and concentration of enzyme on the dyeability of wool fabric is studied. A comparative study between exhaustion and padding techniques of treatment is investigated. Kinetic investigations are also given on the dyeing process of wool fabric with reactive dyes. The treatments revealed improvement in the dyeability of wool with reactive dyes. The use of the enzyme pretreatment enables wool dyeing under mild temperature conditions with increasing dye consumption and an increase of the rate of dyeing. This is reflected as energy saving and reduction of pollution impact.     

Reactive Pad-Batch Dyeing in CORONA Discharged Fabrics

Abstract

The present work aims to the study of the increase of pick-up, together with uniformity degree, concerning the application of reactive dyeing baths by padding in a dry cotton fabric previously treated with CORONA discharge.

Dyeing recipes, with and without wetting agent, are compared and advantages of CORONA discharge are analysed. Reactive dyes are used, expecting also to increase washing fastness of the difficult dark colours due to higher penetration of the dye into the core of the fibres when submitted to plasmatic treatment.

The use of CORONA discharge intends to modify hydrophility of cotton fabrics even when they are presented to padding in hydrophobic state. A good alternative to wetting agent presence in recipes is found and more uniform and intense dyeings are performed in all cases.     

壳聚糖在锦纶织物染色中的应用研究

根据壳聚糖在阴离子染料染色时,可起到使颜色增深的作用特性,先用一定浓度的壳聚糖溶液对锦纶织物进行预处理,然后再用弱酸性染料进行染色,以提高其湿处理牢度。试验结果表明:锦纶织物用弱酸性染料染色时,染浴pH值对染色性能影响显著;经壳聚糖处理以后的锦纶织物,用弱酸性染料进行染色,其染色深度K/S值较未经壳聚糖处理的织物提高90 %左右,即K/S值由1. 946增加到3. 706;染色织物的干、湿摩擦牢度均达到5级;皂洗牢度原样褪色达4~5级,白布沾色达到4级。     

桑叶染色液提取法与染色性能

 为了探索提取方法和提取剂对桑叶染色液染丝绸的效果,采用沸水浴与微波法提取桑叶染色液,结果表明:染色液中的黄酮含量及对丝织物的上染率均以微波法较高。采用微波提取法,通过正交试验研究提取剂对上染率和色光的影响,结果表明对上染率影响最大的是表面活性剂用量,其次为NaOH浓度,再次为表面活性剂种类;对色光影响的次序是NaOH浓度大于表面活性剂用量和种类。采用微波提取法并在NaOH提取剂中加入表面活性剂的桑叶染色液染色效果较好。     

大黄染料用于改性粘胶织物的染色性能

用天然染料大黄染粘胶织物虽然可减少污染，有利环保，但染色性能较差。通过对粘胶纤维改性可使这一问题得到解决。文章介绍了粘胶织物阳离子化处理的机理，并通过正交实验，优化出粘胶织物阳离子改性和染色的最优工艺条件。通过改性粘胶织物和未改性粘胶织物染色试样的对比分析可知：阳离子改性处理对提高天然染料大黄在粘胶织物上的染色性能有明显的效果。     

Eco-Friendly Dyeing of Silk and Cotton Textiles Using Combination of Three Natural Colorants

Silk and cotton fabrics were dyed with combination of three colorants extracted from Acacia catechu (AC), Alkanna tinctoria (AT), and Curcuma Longa (CL) in nine different formulations at 80°C by exhaustion method without mordanting. Dyed samples were evaluated for color value and washing fastness. The biodegradability of dye bath effluent was assessed by measuring the pH, TDS and COD of the residual dye bath liquor. It is inferred that the final color of dyed fabrics from each formulation is governed by the dominant natural dye in the dyeing combination. K/S values inferred that the exhaustion of natural dye is higher in silk fabric than cotton fabric in all formulations. It could be concluded that in the dyeing combination, colorant that have very good affinity towards the functional groups of fibers, itself acts as mordant for other natural colorants.     

Dyeing of Biotreated Jute Fabric

Abstract

Grey jute fabric has been scoured, then treated with a mixed commercial enzyme at a fixed concentration and thereafter bleached with hydrogen peroxide. Three sets of pretreated jute fabric, viz., grey-bleached, scour-bleached and scour-enzyme treated-bleached were dyed with five different class of dyesnamely, direct dye, reactive dye, 1:2 metal complex dye, acid dye and basic dye by conventional dyeing procedure. Analysis of the results reveals noticeable improvement of dye uptake in case of scour-enzyme treated-bleached jute fabric in comparison with only grey-bleached jute fabric. Enzyme treatment also results in improvement of handle property of jute fabric as evident from reduction in bending length values. Scour-enzyme treated-bleached-dyed jute fabric shows some reduction in tensile strength.     

Study of C.I. Reactive Yellow 145, C.I. Reactive Red 238 and C.I. Reactive Blue 235 dyestuffs in order to use them in color formulation. Part 2: modeling and optimization of dyeing performances

Abstract

This article models and optimizes the effect of dyeing parameters on obtained color of fabric samples dyed with three cold bifunctional reactive dyes, namely, C.I. Reactive Yellow 145, C.I. Reactive Red 238 and C.I. Reactive Blue 235, in order to use them in color formulation. The studied dyeing parameters are electrolyte concentration, alkali concentration, liquor-to-fiber ratio and temperature of dyeing process. The influence of these parameters was analyzed for four different shades: 0.1%, 1%, 2% and 4%. Two criteria of evaluation are studied and optimized: the exhaustion and the fixation yields. Linear modeling of optimal concentrations of electrolyte and alkali according to the dye concentration was developed, allowing the calculation of optimal quantities which should be added to the dye bath for any dye concentration. Color coordinates and fastness (washing, rubbing and light fastness) of samples dyed with optimal conditions are also evaluated and discussed.     

棉织物柿漆染色工艺及性能

柿漆作为天然染料,其染色织物具有防水防腐的优点。以赋予棉织物抗菌性和紫外防护性能为目的,采用柿漆对棉织物进行直接染色处理。利用扫描电子显微镜观察棉织物的表观形态,PhabrOmeter织物手感评价测试仪测定织物风格,得到染色棉织物存在硬化问题;探究染色次数和染液浓度对棉织物K/S值、增重率和缩率的影响。通过正交试验设计优化染色工艺,测定染色棉织物的抗菌性能、接触角、紫外线防护性能、色牢度以及风格评价,分析柿漆染色对棉织物性能的影响。结果表明:适宜的染色时间为15 min,柿漆稀释浓度为1∶4,染色次数为8次,染色棉织物色牢度良好,且具有较佳的疏水性能、抗菌性能和抗紫外性能,硬挺度增加。     

棉针织物的练染一浴加工

采用新型反应性直接染料对棉织物进行练染一浴法加工,探讨了反应性直接染料一浴法染色的工艺参数,如染色温度、pH值、染色时间、元明粉用量、浴比、精练剂用量等,对染色织物上染率和表面色深影响,优化确定的练染一浴工艺为:染料2%(omf),精练剂1 g/L,元明粉60 g/L,pH值10.7,浴比1∶30,100℃染60 min。染色织物的色牢度较好。     

亚麻的低温等离子体接枝

采用空气等离子体技术对亚麻纤维以两种不同的接枝方式处理,即先浸渍接枝液,再以等离子体处理,或先以等离子体处理,再浸渍接枝液.以扫描电镜和红外光谱对这两种方法处理的纤维表面形态和接枝效果,以及上染速率和染色牢度进行了比较.结果表明,采用后者的处理效果,明显好于前者,使亚麻纤维的上染速率和染色牢度显著提高.其中初染速率提高2倍,平衡上染百分率达到64 %,染色牢度提高2级.     

Cationization of cotton using cattle hoof and horn for salt-free reactive dyeing

Cattle hoof and horn keratin hydrolysate from cattle hoofs and horns were successfully extracted and used to cationize cotton fabric. The effect of cationization was tested by dyeing the cationized cotton fabric using reactive dyes (cationized sample). The results were compared to conventionally dyed cotton fabric sample without cationization. The UV/VIS absorption result showed 6% improvement in exhaustion; the Color Eye K/S result gave 4.5% improvement in fixation and 6.8% in dye utilization for reactive dye (H-Reactive Red). Acceptable color fastness to washing (4/5) and light fastness (7) were achieved on cationized sample.     

Dyeability,Kinetics and Physico-Chemical Aspects of Bombyx Mori Muslin Silk Fabric with Bi-Functional Reactive Dyes

ABSTRACT

Bombyx mori

muslin silk fabric was dyed with three different bi-functional reactive dyes in exhaust method. Dyeability of the silk fabric was analyzed by reflectance spectra, microscopic appearance, color strength, and saturation limit. Thermal influence on dye exhaustion, migration index, level dyeing factor, and color fastness properties were also investigated. Different kinetic models were approached to study dynamic behavior of dye adsorption and predictability of the models was assessed by co-efficient of regression (r²), root mean square error (RMSE), and mean absolute error (MAE). Some physico-chemical parameters such as activation energy and chemical potential of dyeing were also evaluated. Brilliant color was observed on silk by all class of reactive dyes. A controlled dyeing condition was also suggested to avoid the risk of unlevel dyeing. Wet fastness properties exhibited excellent results on silk fabric. The adsorption data conformed to the pseudo second-order kinetic model with r ² ≥ 0.94 and the activation energy (ΔE) valued (≥55 kJ/mol) within the range of chemisorption for all dyes. The increase of negativity of chemical potential supported higher dye uptake on silk at elevated temperature.