Review of foam applications on cotton textiles

Abstract

The wet processing sector in the textile industry consumes a massive amount of water and energy. In addition, the textile industry generates significant amounts of effluents. Consumer awareness, environmental laws and regulations, water scarcity, and high energy costs have forced textile manufacturers to reduce their water and energy usage. An alternative way to minimize water and energy consumption in textile industries is to alter the chemical finishing processes from conventional water‐assisted systems to foam-assisted systems. This review focuses on the prospects of foam application in textile dyeing and finishing. Here, we summarize the foam application methods on cotton textiles from published peer-reviewed sources. We also analyze and compare the results of the dyeing and finishing parameters of the foam application approach over conventional padding methods. Finally, we propose some suggestions for further research on foam technology for textiles.

Keywords

Foam finishing dyeing textile cotton fabric

Clothing is regarded as one of the basic human needs. As a result, there is a massive demand for textiles worldwide. The clothing manufacturing industry is the sixth largest manufacturing industry globally by market size.¹ It was estimated at US$1000.3 billion in 2020 and is growing with a compound annual growth rate (CAGR) of 4.4%.² The clothing industry combines several interrelated processes, such as yarn spinning, weaving and knitting of fabrics, dyeing and finishing, and garment manufacturing.³

The textile industry is considered a major contributor to environmental pollution.⁴ According to the data of the Ellen MacArthur Foundation,⁵ the global textile industry produces 1.2 billion tons of CO₂-equivalent per year, which places the industry on the same level of emissions as the automobile industry. Among several processes involved in textile manufacturing, dyeing and finishing are particularly problematic, as these processes require a large volume of water to maintain product quality. Although water is an abundant natural resource, only 3% of it is fresh water.⁶ In the textile industry, water is used as a medium for applying dye or finish to the textile and is discharged as effluent at the end of the process.⁷ It was estimated that a dye house with a medium production capacity (∼20,000 lbs/day) uses approximately 36,000 liters of water daily,⁸ which, on a global scale, results in the usage of 3.7 million liters of freshwater every day.⁹

Apart from water, textile effluent contains dyes, pigments, heavy metals, surfactants, oils, greases, etc., which are harmful to human health. Although researchers in academia and textile manufacturers have been working on minimizing the use of harmful chemicals, the situation is still unsatisfactory.¹⁰ It was reported that textile industries use about 3600 different textile dyes and around 8000 chemicals in various textile dyeing, printing, and finishing processes.¹¹

Due to consumers' awareness of environmental pollution, effluent treatment is necessary for manufacturers. However, textile effluent treatment is costly (about 5% of net production cost),⁸ since most synthetic textile dyes have complex structures. As a result, conventional biological treatments are not suitable for effluent decolorization.¹² Nonconventional methods of removing dyes from colored wastewater include adsorption, chemical degradation, biodegradation, and electrocoagulation. These techniques are time-consuming, costly, and often create secondary pollution.¹³ For instance, it takes 19 days to completely degrade indigo blue dye by biological methods.¹⁴ Another way to reduce pollution is to use water conservation methods, such as modifying machinery and optimizing textile dyeing processes. For instance, recent innovations in textile dyeing include micelle dyeing, supercritical fluid dyeing, foam dyeing, and electrochemical dyeing.¹⁵

Another important step in the overall process is drying. In the conventional textile dyeing and finishing processes (via, e.g., wet processing), the drying step is where wet textiles are passed over heated cylinders to remove water or other solvents. Generally, these cylinders are steam-heated¹⁶; hence, the process requires a large amount of energy, 2.5–4.5 GJ/ton.¹⁷

Overall, a traditional dyeing and printing unit consumes a 15% share of the thermal energy spent by composite textile mills, while drying alone uses 17.2% of this share. In 2009, Portugal's textile manufacturing industries consumed about 20.4% of their annual energy in the form of electricity or liquid and gaseous fuel. Boilers – necessary machines for textile dyeing and finishing plants – consume a large amount of natural gas.¹⁸ This means that around 48% of the total thermal energy of a typical textile wet processing plant is being spent in the evaporation process. Therefore, reducing the amount of water that needs to be evaporated is regarded as a way to address the energy high-cost issue.¹⁹

By selecting an alternative group of techniques, so-called low add-on techniques, one can perform the application of chemicals from a solution that is significantly more concentrated. Thus, energy consumption during drying can be minimized.¹⁷ For instance, a recent study explained a new low add-on technology where a dye-jet ejector was used to dye cotton material with reactive dye at a low wet pick-up (WPU) range between 20% and 50%. Even though the authors did not estimate energy consumption, they suggested that potential energy savings make the overall process more environmentally friendly.²⁰ Foam finishing is even more promising: it was shown that the foam-finishing method could save as much as 70–80% energy.²¹

Foam finishing (during applications of dye, pigment, or finishes) represents one of the potential water-saving processes^22,23 because it requires lower WPU than conventional textile finishing.²⁴ Foam finishing is a lower WPU process because finishing agents are applied onto a textile surface through a foam medium.²⁵ The volume of a finishing solution is expanded 5–25 times in the foam-finishing process compared to traditional application methods,²⁶ resulting in a 25–35% lower WPU.²¹ As a result, the method uses 30–90% less water than traditional processes such as padding.²⁷ Foam technology, including foam mercerization, foam dyeing, foam printing, and foam finishing, received a lot of attention in the 1970s and 1980s due to energy shortages and growing energy costs.²⁸

Apart from saving water, foam technology can reduce the uneven distribution of reagents on the fabric surface because of a more concentrated solution.²⁹ In addition, successive incremental application of color in foam-finishing machines has eliminated uneven fabric dyeing.³⁰ Furthermore, foam technology can be used for single-sided applications of dyes or finishes on either the face or backside of the fabric.²¹ An extra advantage is that foam finishing can be used before or after padding with different finishes.³¹

Despite all of the advantages mentioned above, studies of foam finishing are surprisingly limited. The search phrase “low wet pick-up” AND “foam,” AND “cotton,” OR “textile” in Google Scholar generated only 71 journal articles and patents in total related to foam application on textiles up to 17 December 2021 (Figure 1).

Figure 1.

Historical plot of the number of available scholarly publications using “low wet pick-up,” and “foam,” and “cotton,” or “textile” as search keywords or phrase (using Google Scholar, December 2021).

Interest in foam applications started as early as 1907, and research in this field was cutting edge in 1984. However, the adoption of foam-finishing technology (FFT) in the textile industry is inadequate,³² likely due to the lack of technological development and related limitations, such as low penetration of dyes or finishes into materials.³³ This review discusses a brief history of the development and challenges in the foam-finishing system, process variables, chemicals, and additives, and reports on industrial adoption. Because foam-finishing techniques are efficient methods for decreasing the effluent load while reducing water and energy consumption in the textile industry, this review focuses on the latest research findings related to foam-finishing systems as alternatives for the traditional padding methods of dyeing and finishing. A word cloud has been generated using the present paper, which embodies the essence of the whole text (Figure 2).

Figure 2.

A word cloud based on the current article. The larger the term, the higher the frequency.

A brief history of foam-finishing technology

The available literature reveals that foam technology for textile treatment was introduced in 1906. A Swiss scientist passed pressurized air through heated soapy water to turn the liquor into a foam. This foam was used for silk degumming,^34,35 the first step of silk yarn manufacturing where sericin gets removed from the silk fibroin.³⁶

After that, a group of researchers invented a process in which silk textile materials were degummed and dyed with a foamed composition containing the required chemicals. They used soap to produce bubbles of minimal diameter (less than 0.25 or 0.125 inches) and uniform size distribution. Their invented machinery could generate the foam, whose bubbles carried finishing chemicals onto the materials.³⁷ A study described textile printing using foam-based printing solutions. A foam printing paste was made by mixing a dye, a thickener, a stabilizer, and an emulsifier. The paste was then applied to the material surface using an engraved printing roller.³⁸ Nylon textile material was dyed with a dye liquor containing a foaming agent in a steam-jacketed drum.³⁹

In 1976, Union Carbide Corporation invented the FFT process, which employed high shear sensitive semi-stable foam that had sufficient stability to be transported from the foam generator to the applicator. However, this type of foam was not stable enough to withstand the shear force generated by the applicator, resulting in foam breaking and uncontrolled spreading over the material surface.⁴⁰ The Union Carbide Corp. and Gaston County Dyeing Machine Co. formed a joint venture a year later to design a foam application machine that could apply semi-stable foam to the fabric surface. Later, an efficient foam application equipment was designed by the Gaston County Dyeing Machine Co.⁴¹ An anonymous textile mill made a prototype machine soon after that. The Union Carbide Corp. and Gaston County Dyeing Machine Co. announced in 1978 that they had developed a machine for applying chemicals to a moving textile substrate. The equipment was presented at the “48th Textile Research Institute annual research and technology conference” in 1978.⁴²

Industrial application of the foam technology started within a year. Some US textile mills, including Greenwood Mills (SC, USA), adopted the technology and ran the one-sided application (bottom applicator) of foamed finishing composition in various fabrics. Later on, Gaston County Dyeing Machine Co. incorporated a top applicator into its system for two-sided applications for the Greenwood mill management.⁴¹

Gaston County Dyeing Machine Co. continued the research in foam application and patented at least six of its inventions.^43–48 Two crucial problems that appeared when finishing the moving substrate were solved. A parabolic applicator for uniform foam application was incorporated by allowing the foam to travel the same path length, starting from its generation to the fabric surface.³¹ In addition, in 2008, a multiple foam head unit or applicator that can apply dyes uniformly to produce level dyed fabric was invented by Gaston Systems.³⁰

Variables of a foam composition

Foam properties are very important for foam-finishing systems because foam characteristics can be different for various foam application heads.^49,50 For example, stable foam and semi-stable foam together cannot be used in the same type of application nozzle or machine.⁵¹ Some major foam properties are the blow ratio, foam density, foam half-life, foam viscosity, bubble size or diameter, shear sensitivity, and wetting rate.⁴⁹ In the following sections, a brief discussion of the important foam properties will be presented.

Foam stability and half-life

“Foam stability is defined as the time that foam will maintain its initial properties as generated.”⁵² The stability of foam is required for its transportation and handling, but foams that are too stable provide poor penetration into the fabric. Foam stability is affected by many factors, such as the surface tension of the foaming solution, surface and solution viscosity, pressure and bubble size distribution, and an application temperature.⁵³ With time, small bubbles in a foam tend to either collapse or coalesce into larger bubbles through gas migration. Consequently, a flow of excess liquid occurs through the curved triangular junction of the fluid or plateau borders with the help of capillary action and gravitational force.^54,55 In this case, foam can lose its structure and become unstable due to drainage, coalescence, disproportionation, and loss of a considerable amount of gas.⁵⁴ Temperature has an indirect effect on foam stability. It has been reported that foam stability is directly proportional to the viscosity of liquid film. Again, the viscosity of the liquid membrane is highly affected by the temperature. The viscosity of liquids falls rapidly at elevated temperatures. As a result, foam stability decreases with the increase in temperature.⁵⁶ Foam has varied stability at different pressures. Foam becomes more stable as more pressure is applied. The surface tension of the liquid film of smaller bubbles is lower, whereas the surface tension of the film of larger bubbles is greater. At elevated pressure, the Gibbs–Marangoni effect increases, which permits liquids to flow from a low surface tension area to a high surface tension area. Thus, the average bubble size reduces at high pressure, increasing the stability of foams.⁵⁷

The stability of foam is the time required to lose either 50% of the liquid or 50% of the volume from the foam (so-called half-life time) by self-collapsing.⁵⁸ Technically, if X mL of foam were prepared from 40 mL of liquid and let drain by itself, the half-life would be the time required to collect 20 mL of liquid from it (Figure 3).³³ Stability can be determined by either static or dynamic methods. In the static method, the stability of foam is measured after the foam has been made, using, for example, Ross and Clark static method.⁵⁹ In the dynamic method, the assessment is done while the foam is being made. Some dynamic ways of measuring the foam stability include the Bikerman method, Ostwald and Mischke method, Pankhurst method, etc.⁵⁹ It should be noted that foam drainage and instability increase with the increase in the temperature,²⁶ although this depends on a particular system.

Figure 3.

Schematic representation of foam stability through measuring foam half-life time: (a) initial foams and (b) half-time of foams.

Foam half-life can be different for various textile processing, for example, 30–45 min for finishing and 30–180 min for dyeing.^51,60 Studies have shown that anionic surfactants have an average half-life of 48.5 min, which is the maximum among all other surfactants used in textile foam processing.⁶¹

Foam expansion ratio or blow ratio

The blow ratio is another important variable when working with foams. It is defined as the ratio of the volume of foam formed to a volume of liquor (liquid) used to generate the foam.⁵⁸ For example, an expansion ratio of 20 means 20 mL of foam is produced from 1 mL of liquid.⁶² Foams having an expansion ratio or foaming ratio in the range from 5 to 10 are preferable for textile applications.⁶⁰ In addition, the shape of the bubbles in a foam varies with the change in the blow ratio.⁶³ In textile finishing, the concentration of finishing agents in the foam decreases with the increase in the expansion ratio.²¹ However, the blow ratio alone does not affect the dye fixation rate or the shade depth of the dyed fabric.²⁸

Density

The foam density is the mass of a freshly prepared foam divided by the foam volume. Foam density is measured simply by weighing a graduated cylinder filled with the foam or by collecting the foam in a paper cup and comparing the mass of the foam to the mass of an equal volume of water in the same cup.⁶⁰ For finishing and dyeing of textile goods, foam density is directly proportional to the mass per unit area of the goods because low foam density results in low WPU.⁵¹ The density of foam used in textiles varies from 0.01 to 0.03 g/cm³.⁴⁹ Furthermore, the blow ratio and the foam density are inversely proportional to each other, and most of the time, the foam density is mentioned along with the blow ratio.^21,58 If a liquid containing a foaming agent has approximately 1 g/cm³ density before foaming, then the density of the produced foam would be the inverse of the blow ratio.⁶⁴

Viscosity

The performance and stability of fabric coatings (i.e., the amount of coating delivered to the fabric, the uniformity of coating, its thickness, and spreading) are influenced by foam rheology. Thus, an understanding of viscosities across a range of shear conditions and temperatures allows for identifying optimal coating conditions. By definition, the foam viscosity measures the foam resistance to flow when the bubble walls are still in a liquid state. Generally, the viscosity of the foam for textile applications ranges between 2000 and 3000 mPa.⁵¹ For textile finishing, where finishes are applied to achieve a surface coating or modification (such as sizing), it is crucial to maintain the required foam viscosity because a low viscosity results in a rapid liquid penetration into the material.⁶⁵ The viscosity increases with the increase in the expansion ratio.²¹ The viscosity of the foam film can be measured by a Brookfield viscometer, Fann VG meter, and Epprecht coaxial-cylinder viscometer.⁶⁶ Figure 4 shows the relationship among the blow ratio, viscosity, and foam density.

Figure 4.

Foam density and foam viscosity as a function of blow ratio. Adapted from Namboodri and Duke.²¹

Foaming ingredients

Foaming ingredients are essential chemicals required to prepare foam with the desired properties. Basic foam ingredients include surfactants, viscosity modifiers, stabilizers, etc. In addition, a foam for textile finishing or dyeing can contain resin, dye, pigment, etc. Because they impart some functional qualities to the applied substance, they are called functional ingredients. Moreover, the application requires catalysts, co-polymers, or binders to entangle the pigment into the fabric, softeners, pH modifiers, electrolytes, etc. All foaming ingredients should serve the purpose of forming a foam with the desired half-life, foam density, viscosity, shear sensitivity, wetting rate, etc.⁵¹ In the following sections, we briefly discuss some of the required foaming ingredients.

Surfactants

Surfactants, also known as surface-active agents, are molecules that self-assemble into micelles in a liquid and adsorb to the interface between the liquid and a different phase (gases or solids).⁶⁷ Their heads are hydrophilic (polar), whereas their tails are hydrophobic. Ionic (anionic, cationic, and amphoteric) and nonionic surfactants are the two types of surfactants.⁶⁷ Pure liquids (mainly water) produce bubbles but not foams because the thin liquid films between bubbles are fragile. Adding the appropriate foaming agent to a liquid increases the stability of liquid films and the production of foams. Surfactants are the most prevalent foaming agents.⁶⁸ Table 1 shows the foaming ratio and half-life of five commercial surfactants.

Table 1.

Properties of different surfactants or foaming agents; adapted from Zhu et al.⁶⁹

Surfactants	Foaming ratio	t_1/2, sec
Sodium dodecyl sulfate (SDS)	4.50	141
Tween-80 (T-80)	4.34	129
Dodecyl dimethyl betaine (BS-12)	4.39	127
Sodium lauryl polyoxyethylene ether sulfate (AES)	4.35	137
Lauryl dimethyl amine oxide (OB-2)	4.42	126

Stabilizers

To create foam from a liquid, the lamellae around the air bubble must have the least elasticity or resilience so that an opposing force can counteract any tension imparted to the foam.⁷⁰ This physical property of the foam is known as elasticity. Stabilizers are used to enhance the elasticity of the film. The foam used in the foam dyeing process must be sturdy enough to be distributed through the applicator tip without collapsing.²⁸ It was reported that when sodium dodecyl sulfate (SDS) is employed alone in the foam dyeing liquid, the formed foam is unstable (bursts within minutes). Dodecanol acts as a good stabilizer when used with SDS.⁷¹ The addition of dodecanol to the SDS can increase the density of the surfactant at the air–liquid boundary, increase the strength of the foam film, and improve the foam properties.²⁸

Thickeners

Thickeners are used to increase the viscosity of the lamellae or film separating the bubbles. They slow down the draining of the inter-lamellar compound when applied to the material surface. Hydroxyethylcellulose (HEC) is a widely used thickener for foam processing of cotton textiles.²⁶ Some other suitable thickeners for textile foam applications are guar gum, sodium alginate, sodium carboxymethylcellulose, polyvinyl alcohol, etc.⁵¹ Stable and homogeneous foam was achieved by using 1.5 g/L thickener with 35 g/L of foaming agent for an easy-care finish of the textile.⁷² By introducing a thickener, higher stability and foam viscosity can be attained. The stability of the foams produced from the solution having 2 g/L of SDS and 2.5 g/L of different thickeners is shown in Figure 5. Guar gum outperformed other thickeners in terms of foam stability. Moreover, the composite system of dodecanol and guar gum (3:4) resulted in the highest foam stability (Figure 6).²⁸

Figure 5.

Foam stability (measured in half-life, t_1/2) of different thickeners. Adapted from Yu et al.²⁸

Figure 6.

Foam stability of dodecanol–guar gum composite stabilizing system. Adapted from Yu et al.²⁸ SDS: sodium dodecyl sulfate.

Overview of the foam technology for cotton textiles

Foam technology for textiles has been extensively studied since 1979.^21,73,74 Since then, textile industries have been trying to adopt this newer technology to achieve environmental and economic advantages over conventional processes. Foam technology was reported as one of the viable approaches to reducing water usage in the textile industry.^15,32 The poor adoption rate of this technology can be attributed to its technical limitations, such as low chemical penetration and distribution, dyeing inconsistency, failure to apply particular finishes, and limited applicability of the technology for tubular knitted fabric.⁷⁵ The next section will briefly review the research and industrial adoption of foam finishing and dyeing of cotton textiles.

Pretreatment

Cotton fabric is typically pre-treated before being subjected to chemical modification (i.e., desizing, scouring, bleaching, and mercerization).⁷⁶ Stage-wise, warp cotton yarns normally undergo a process called yarn sizing. During this process, warp cotton yarns are coated with a thin film of adhesive to bind the yarn by adhering the fibers together and improving yarn strength before weaving. It is necessary to remove the sizing agent before dyeing or printing by desizing.⁷⁷ Then, an alkaline scouring removes oil, wax, or other natural impurities and increases fabric absorbency.⁷⁸ Bleaching removes the natural grey color of cotton and improves the luster of the cotton fabric or yarn surface.⁷⁹ Finally, cotton is mercerized using concentrated sodium hydroxide to improve its strength, luster, and dyeability.⁸⁰

Researchers at Auburn University have been looking at using foam in sizing. They used a modified Callaway slasher to size 50/50 polyester/cotton 27 tex single yarns. The knife-over-roll coating and horizontal pad coating techniques were tested (Figure 7). Foam sizing of polyester/cotton yarns resulted in properties comparable to or better than yarns sized by traditional techniques. Techno-economic analysis revealed that US$27,000 per slasher per year could be saved in the foam sizing process.⁸¹

Figure 7.

Schematic representation of foam applicators: (a) knife over roll and (b) horizontal pad foam applicators.

Another process for applying foams is foam-assisted mercerization. Typically, cotton fibers are mercerized by soaking them in a strong sodium hydroxide solution. In a foam-assisted process, sodium hydroxide was applied to a particular side of the cloth while the opposite side of the cloth remained unmercerized. As shown in Table 2, the foam-mercerized side produced an almost identical shade to the ordinary mercerized sample. In contrast, the opposite side produced a shade comparable to the untreated sample.⁸²

Table 2.

Relative color strength (K/S) of dyed samples; adapted from Turner et al.⁸²

Sample	Color strength (K/S)
Untreated fabric	100
Conventional mercerized	147
Foamed mercerized side	136
Side opposite foam mercerization	99

The Reed-Chatwood size applicator (schematically shown in Figure 8) was used to perform large-scale sizing experiments using spun polyester/cotton warp yams. The encapsulation of the yam was consistent, and scanning electron microscopy (SEM) micrographs of the cross-section of foam-sized yarn revealed no excessive penetration. The structure of the unit was based on the notion of horizontal padding.⁸³

Figure 8.

Schematic diagram of the Reed-Chatwood foam applicator unit.

A composite foaming agent and stabilizer can be used in foam sizing. Zhu et al.⁶⁵ reported on an oxidized starch/polyacrylic acid composite sizing agent. They optimized the concentrations and blending ratios of the composite sizing material, composite foaming agent, and composite foam stabilizer. According to their report, the foam properties reached an optimal point (8%, 2%, and 5% increase in foaming ratio, stability, and viscosity, respectively) when composite ratios and concentrations were as indicated in Table 3.

Table 3.

Optimized parameters for oxidized starch/polyacrylic acid blended sizing material; adapted from Zhu et al.^65,69

Ingredients	Composition	Ratio	Concentration
Sizing materials	Oxidized starch/polyacrylic acid	1:1	10%
Foaming agent	SDS/dodecyldimethylbetaine	4:1	6 g/L
Foam stabilizer	Dodecanol/guar gum	3:2	4 g/L

SDS: sodium dodecyl sulfate.

To compare yarn characteristics, oxidized starch and polyacrylic acid were mixed 50:50 and sized to cotton yarns at a 10 wt% concentration. The same sizing agents were used for the foam-sizing of cotton yarns. As a result, at optimal conditions (see Table 3), the foam sizing yarn qualities outperformed traditional sizing (Table 4).

Table 4.

Mechanical properties of foam-sized and conventionally sized yarns; adapted from Zhu et al.⁶⁹

Description	Size pick-up (%)	Breaking strength (cN/tex)	Elongation (%)	Abrasion resistance (times)	Hairiness (piece/m)
Unsized	0	14.94	8.74	70.13	19.49
Conventional-sized	8.02	21.48	5.97	139.27	7.55
Foam-sized	5.06	20.85	6.26	129.75	7.45

Dyeing

Dyeing is a value-added treatment for textile materials, which transfers the dye molecules from an aqueous medium onto the material surface, then diffuses them into the material.⁸⁴ There are at least eight dye classes – direct, vat, sulfur, azoic, reactive, acid, disperse, and basic dyes.⁸⁵ Among them, reactive dyes are very suitable for cellulosic materials, such as cotton, as they are easy to apply and can impart long-lasting brilliant shades on the material.⁸⁶ On the other hand, vat dyes are a special type of colorant because they are insoluble in their pure or original form and need a reduction step to turn into water-soluble colorants (reduced condition) before the actual dyeing.⁸⁷ Several attempts have been made to dye cotton textiles by a foam medium instead of the conventional aqueous solution. In most cases, foam-dyed cotton fabrics have excelled over traditional pad-dyed materials in color parameters. Comparisons of color strength and rubbing fastnesses of foam-dyed and conventional pad-dyed cotton fabrics are given in Table 5.

Table 5.

Comparison of color parameters of foam-dyed and conventional pad-dyed cotton fabrics

Dye/pigment used	Dye/pigment concentration	Color strength (K/S)		Rubbing fastness				Ref.
		Color strength (K/S)		Dry		Wet
		Foam dyeing	Conventional pad dyeing	Foam dyeing	Conventional pad dyeing	Foam dyeing	Conventional pad dyeing
CI Reactive Red 120	1.8 (o.w.f.)	15	12	5	5	2–3	2	²⁸
Reactive Orange 16	3% (o.w.f.)	12.53	–	–	–	–	–	⁸⁸
Reactive Blue 184	3% (o.w.f.)	18.24	–	–	–	–	–	⁸⁸
Reactive Blue 19	3% (o.w.f.)	9.89	–	–	–	–	–	⁸⁸
Acid Orange 74	3% (o.w.f.)	7.36	–	–	–	–	–	⁸⁸
Intracron Red VS-4BL	3% (o.w.f.)	12.53	–	–	–	–	–	⁸⁸
Brand A (Black)	100 g/L	–	–	3	5	3	2.5	³⁰
Levafix Navy CA	5% (o.w.f.)	15	15	4–5	4–5	4–5	4–5	⁸⁹
CI Pigment Red 254	6% (o.w.f.)	7.8	–	4	–	3–4	–	⁶²
Printofix Yellow T-G	100 g/L	–	–	4	–	2	–	³³
Printofix Black T-M	100 g/L	–	–	3–4	–	3	–	³³
Printofix Navy T-V	100 g/L	–	–	3–4	–	2–3	–	³³
Printofix Blue T-K	100 g/L	–	–	4	–	4	–	³³

The indigo dyeing of cellulosic textile material by a foam medium, foamed by an inert gas, started in the mid-1980s. Berendt H-U and Schafer P⁹⁰ described preparing a foamed composition by mixing indigo dye, acrylamide polymer, foaming agent, alkali, and reducing agent, followed by foaming with nitrogen gas. The oxidation procedure was carried out after dyeing to impart the actual color. However, the dyeing was not conducted in a closed environment, resulting in the dye's premature oxidation to some extent.

To overcome the limitations of Ciba-Geigy's work and prevent the dye's premature oxidation, Gaston Systems designed a sealed chamber dyeing unit capable of delivering the foamed composition of leuco vat dye; the foaming was done with nitrogen.⁴⁷ The Gaston system used a sealed chamber, giving room to the moving cellulosic textile material, containing a parabolic-shaped multiple head applicator (Figure 9). Researchers argued that multiple head applicators facilitated the development of deeper shade in the dyed substrate.⁴⁷

Figure 9.

Parabolic foam distribution chamber. Adapted from Basyigit et al.³¹

In another study, the dyeing was conducted by immersing a pure cotton fabric into a foamed bath containing vat dye, followed by padding. The dye was then reduced with a reducing agent and oxidized by environmental oxygen. The authors compared the properties of the dyes to retain their characteristics under exposure to light and washing (so-called fastness properties) for a foam-dyed fabric with the fabric dyed by a conventional method and found comparable results between the two.⁹¹

Later on, Indigo Mill Designs, LLC, developed a continuous system to dye a cotton yarn sheet with pre-reduced foamed indigo dye in an oxygen-free environment. The material was allowed to pass through three subsequent anaerobic purge chambers. The second chamber was equipped with foam applicators to apply the foam to the passing sheet of yarns. The last chamber, the dwell chamber, provided the necessary moisture to diffuse the dye molecules. The dyed yarns then passed into an oxidation chamber where the dye molecules were oxidized to develop a blue color.⁹²

In another study, researchers dyed 100% cotton fabric using a reactive dye, immersing the material into a foamed medium containing a foaming agent and a dye. Then, alkali was added to the solution and padding was carried out, followed by washing, soaping, and drying. The treated cloth showed similar colorfastness compared to the conventionally dyed fabric.⁹³

Researchers aimed to make a single-sided reactive dyed cotton fabric in yet another work. They treated the face side of the fabric using dimethyl dihydroxy ethylene urea (DMDHEU) cross-linker added to the foaming liquor. When dyed with reactive dye in the exhaust system in acidic conditions, the foam pre-treated fabric exhibited high color contrast between the two sides. The face side was dyed well, while the rear side remained almost undyed. The authors claimed that garments made with this kind of cross-linked fabric have the potential for further aesthetic finishing in their garment forms, such as garment dyeing and acid washing.⁸⁸

Farias³⁰ successfully carried out the foam dyeing of woven fabric with bi-functional reactive dyes. In this study, cotton fabric was dyed using the foam-dry-bake and foam-batch methods. The foam was applied using a multiple foam head applicator apparatus from Gaston Systems (USA) to achieve a uniform distribution of dyes. The foam-dyed fabric did not show better colorfastness results than traditionally dyed fabric. However, the author claimed that foam dyeing was more energy-efficient. Moreover, the author argued that the foam-dry-bake process eliminated the steaming process required for traditional reactive pad dyeing, thus eliminating dye migration.³⁰

The system developed by Neowin Chemicals Co., Ltd, China (“Neovi-foam system”), has been used to develop a novel method for foam dyeing of cotton fabric using a reactive dye; Figure 10 illustrates the foam dyeing process. Two-bath pad-steam dyeing of cotton fabric with CI Reactive Red 120 (WPU 80%) was used compared to foam dyeing (WPU 30%).²⁸

Figure 10.

Foam dyeing process. Adapted from Yu et al.²⁸ RH: relative humidity.

CI Reactive Red 120 showed a better color build-up property and colorfastness in foam dyeing than the conventional pad-steam dyed system. Figure 11 shows the color build-up (K/S) values of CI Reactive Red 120 in foam dyeing and conventional dyeing. When compared to traditional dyeing, foam dyeing significantly reduced water and energy consumption.²⁸

Figure 11.

Build-up properties of dyestuff (measured by color strength, K/S value) in foam dyeing and conventional dyeing. Adapted from Yu et al.²⁸

In later studies, researchers extracted keratin hydrolysate from wool and used it as a foaming agent in foam dyeing of cotton fabric using a reactive dye. The dyeing and colorfastness properties of foam-dyed fabric were compared with the conventionally dyed cotton cloth. Results indicated that the foam dyeing process colorfastness and strength were comparable to those of traditionally pad-dyed fabrics.⁸⁹

Similarly, 100% cotton fabric was foam-dyed with the pigment using polyoxyethylene ether, C₁₄(EO)₅, as both a foaming agent and stabilizer. Results revealed that foamability and stability improved with increasing C₁₄(EO)₅ concentration, owing to increased viscosity. In addition, the colored cotton cloth had a high color strength (measured by K/S value) and flawless color levelness and colorfastness. These findings showed that using a C₁₄(EO)₅ foam controller with dye pigment foam enhanced color depth and levelness.⁶²

One-sided padding of cotton cloth with foam pigment dyeing liquid was also conducted with a horizontal padder. The K/S values of textiles colored using the foam technique are greater than those colored with liquid padding in the same pigment quantity (Figure 12). The serviceability, such as moisture absorption and handling property, was much enhanced in the foam dyeing process. Finally, the benefits of energy conservation and chemical reduction were achieved throughout the dyeing process.³³

Figure 12.

Effect of pigment amount on color strength. Adapted from Shang et al.³³

Foam finishing

Usually, easy-care or durable press finishing is used on cotton textile materials to provide resistance against shrinkage and improve wet and dry wrinkle recovery; this is typically done using cross-linking agents.⁹⁴ The reason for the formation of wrinkles is water absorption during washing and drying, which results in hydrogen bond breakage and slippage of the cellulosic chains in the amorphous regions. Cross-linking allows fixation of cellulose chains by establishing covalent bonds, inhibiting their movement.⁹⁵

DMDHEU and its derivatives, triazones, melamines, and carbamates, are used to cross-link cellulosic material. Although flagged for its environmental and health risks due to the release of formaldehyde, DMDHEU is the most often used cross-linker for cotton textile material.⁹⁶ Scheme 1 shows the reaction of DMDHEU with cotton cellulose.

Foam technology can be a viable alternative to traditional methods for improved mechanical properties of cross-linked textile materials.⁹⁷ Many studies have been conducted on foam-assisted easy-care or durable press finishing on cotton textile materials using DMDHEU. An osnaburg fabric, treated with a foamed solution of DMDHEU, was tested for its qualities and the distribution of reagent residues. Foam-finished fabric (35% WPU) met the standard uniformity criteria.⁹⁸

DMDHEU and modified DMDHEU were applied to cotton textiles utilizing a foam-finishing procedure. Both finishing agents appeared to have a more homogenous distribution when treated with foam application than the traditionally finished fabrics. More cotton cellulose was cross-linked throughout the fabric surface because of the more homogenous distribution of the finishing agents, resulting in a larger wrinkle recovery angle for foam-finished fabrics than for traditionally finished fabrics.⁹⁹

Later on, etherified DMDHEU was used as a cross-linking agent in the presence of a strength-retaining agent for foam-finishing cotton woven fabric. Compared to conventional padding system, foam-finished fabric provided more wrinkle recovery and improved tear and breaking strength.⁹⁷ Sarwar et al.⁷² worked on durable press finishing of cotton denim fabric using dihydroxy ethylene urea (DHEU) by the foam-finishing system. From comparing the performance properties, it was clear that the tearing strength was better in the foam application system than in the conventional padding system. The authors attributed this improvement to the reduced WPU, even distribution of reagent, and regular cross-linking in the foam-finished fabric.⁹⁷

Physical properties of the cotton fabric, finished by foam application of formaldehyde, were explained in terms of processing factors in a study that employed statistical experimental design and multiple stepwise regression analysis. Results indicated that the combined effect of the curing temperature and the catalyst ratio was responsible for tensile and tearing strengths loss.¹⁰⁰ Later, the formaldehyde release property of finished fabric was studied and it was discovered that formaldehyde concentration combined with the WPU is responsible for formaldehyde release.¹⁰¹

Flame retardancy is the ability to hinder or resist the spread of fire. Flame-retardant fabrics are used in various applications, including the production of firefighter and military/police uniforms. Common flame-retardant agents are sulfamic acid, ammonium sulfamate, zinc chloride, and phosphoric acid. They release acids upon heating, thus causing dehydration of cellulose and promoting char formation. To create flame-retardant cotton, 1–2% of the phosphorus content relative to the weight of the fabric is usually sufficient.¹⁰² Phosphorus-based flame-retardant coatings to cotton textiles have been applied using foam application. The char length of foam-finished flame-retardant fabric was similar to that of a traditionally finished sample (Figure 13). The foam approach did not have a substantial advantage over the traditional process in terms of the flame-retardant property.¹⁰³

Figure 13.

Char length of foam-finished and conventional pad-finished flame-retardant fabric. Adapted from Gregorian et al.¹⁰³

In another study, the authors prepared multifunctional cotton cloths using flame-retardant, antimicrobial, and water-repellent agents. For this, a foam system applied 400 g/L dialkyl phosphono carboxylic acid amide (flame retardant) to cotton fabric. The foam-finishing process gave similar char length (cm) and durability as the conventional pad-finished fabric (Figure 14).³¹

Figure 14.

Durability of foam-finished and pad-finished flame-retardant fabric. Adapted from Basyigit et al.³¹

Water and oil repellencies are important functional qualities that need to be considered for protective garments.¹⁰⁴ Fluorinated agents are the most extensively utilized finishes for textile processing because of their low surface energy (γC ∼ 15 dynes/cm or less), which allows them to resist both water and oils.¹⁰⁵ Several approaches have been adopted to produce water- and oil-repellent cotton fabric using foam technology.^106–108

One-sided foamed application of fluorochemical (FC) on two different pre-treated cotton fabrics was investigated. The finished side exhibited outstanding water and oil repellency, whereas the side of the fabric to which the finish was not applied was water-absorbent. Water and oil repellency increased with the amount of fluorinated agent from 0.75 to 1.00 to 1.25% (Figure 15), as expected.¹⁰⁹

Figure 15.

Water repellency (a) and oil repellency (b) ratings of fluorochemical (FC) finished fabric. Adapted from Wadsworth and Wey.¹⁰⁹

Another paper described a simple foam-finishing procedure to create single-faced superhydrophobic cotton textiles. The fluoropolymer emulsion foam was applied to cotton fabric and distributed using a knife coater over the fabric surface. The obtained material showed high hydrophobicity on the applied side, whereas the unapplied side remained hydrophilic (Figure 16). Fluoropolymer withstood up to five washing and drying cycles.¹⁰⁶

Figure 16.

Scheme 1.

Crosslinking of cellulose with dimethyl dihydroxy ethylene urea (DMDHEU).

Conclusions and outlook on future research

Foam-finishing methods reduce the processing time, amount of required chemicals, water, and energy while producing a fabric with improved properties. The foam method works better where complete chemical penetration is not required, such as in sizing and resin finishing. Foam-finished textiles are more eco-friendly, economical, and functional than traditional padded textiles. Consumers are becoming more concerned about sustainability, particularly in growing countries like China, India, and Mexico, underlining the need for retailers to address the environmental effect of their products. According to new GreenPoint research, Americans look for ecologically friendly items and are ready to pay a premium. Brands may use foam dyeing technology to make garments, which will match consumer demand for environmentally friendly products. Wrangler is, to our knowledge, the first company to commit to releasing the first foam-dyed denim on the market. It teamed up with Texas Tech University (TTU) and Tejidos Royo, a Valencia-based textile manufacturer, to develop a foam-dyed, water-free technique that eliminated waste from conventional dyeing methods. According to Wrangler, their technology could save 8 billion liters of water per year only in the USA.

However, foam application is more challenging to control than aqueous pad application. Multiple parameters, such as foam stability, density, viscosity, and homogeneous bubble size, must be controlled. Selecting a foaming agent, a compatible thickener, and a stabilizer is necessary to achieve maximum benefit from foam media. Achieving deeper shades, level dyeing, and better colorfastness can be problematic in foam dyeing.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Ejajul Hoque

Julia Shamshina

Noureddine Abidi

References

ibisworld.com. Global apparel manufacturing – market size 2005–2027, https://www.ibisworld.com/global/market-size/global-apparel-manufacturing/ (2021, accessed 24 April 2022).

MarketResearch.com. Textile market size, share & trends analysis report by raw material (wool, chemical, silk), by product (natural fibers, polyester), by application (household, technical), by region, and segment forecasts, 2021–2028, https://www.marketresearch.com/Grand-View-Research-v4060/Textile-Size-Share-Trends-Raw-14317142/ (2021, accessed 17 December 2021).

Alkaya

Demirer

GN.

Sustainable textile production: a case study from a woven fabric manufacturing mill in Turkey. J Clean Prod 2014; 65: 595–603.

Maheshwari U. A review on adsorption process for the removal of dyes from textile industry effluent. In: 2013 AIChE annual meeting, Virtual, 3-8 November 2013, paper no. 395ax. San Francisco, CA, USA: AIChE.

Ellen MacArthur Foundation. A new textiles economy: redesigning fashion’s future, https://ellenmacarthurfoundation.org/a-new-textiles-economy (2021, accessed 17 December 2021).

National-Geographic. Freshwater access, http://www.nationalgeographic.org/encyclopedia/freshwater-access/ (2019, accessed 24 April 2022).

Hessel

Allegre

Maisseu

, et al. Guidelines and legislation for dye house effluents. J Environ Manage 2007; 83: 171–180.

Shaikh

MA.

Water conservation in textile industry. Pak Text J 2009; 58: 48–51.

Buthiyappan

Aziz

ARA

Daud

WMAW.

Recent advances and prospects of catalytic advanced oxidation process in treating textile effluents. Rev Chem Eng 2015; 32: 1–47.

10.

Chen

H-L

Burns

LD.

Environmental analysis of textile products. Cloth Text Res J 2006; 24: 248–261.

11.

Kant

Textile dyeing industry an environmental hazard. Nat Sci 2012; 4: 22–26.

12.

Robinson

McMullan

Marchant

, et al. Remediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative. Bioresour Technol 2001; 77: 247–255.

13.

Daneshvar

Oladegaragoze

Djafarzadeh

Decolorization of basic dye solutions by electrocoagulation: an investigation of the effect of operational parameters. J Hazard Mater 2006; 129: 116–122.

14.

Vikrant

Giri

Raza

, et al. Recent advancements in bioremediation of dye: current status and challenges. Bioresour Technol 2018; 253: 355–367.

15.

Hussain

Wahab

A critical review of the current water conservation practices in textile wet processing. J Clean Prod 2018; 198: 806–819.

16.

Ozturk

HK.

Energy usage and cost in textile industry: a case study for Turkey. Energy 2005; 30: 2424–2446.

17.

Hasanbeigi

Price

A review of energy use and energy efficiency technologies for the textile industry. Renew Sustain Energy Rev 2012; 16: 3648–3665.

18.

Nunes

LJR

Matias

JCO

Catalão

JPS.

Analysis of the use of biomass as an energy alternative for the Portuguese textile dyeing industry. Energy 2015; 84: 503–508.

19.

Brown

Bryant

Young

, et al . Extending the lower limit of wet pickup in foam finishing of cotton fabric. Text Chem Color 1983; 15: 27–31.

20.

Xiaodong

Hong

, et al . A novel low add-on technology of dyeing cotton fabric with reactive dyestuff. Text Res J 2018; 88: 1345–1355.

21.

Namboodri

Duke

MW.

Foam finishing of cotton-containing textiles. Text Res J 1979; 49: 156–162.

22.

Gopalakrishnan

Punitha

Saravanan

Water conservation in textile wet processing. In: Muthu SS (ed.) Water in textiles and fashion. Cambridge: Woodhead Publishing, 2019, pp.135–153.

23.

Samanta KK, Pandit P, Samanta P, et al. Water consumption in textile processing and sustainable approaches for its conservation. In: Muthu SS (ed.) Water in textiles and fashion. Cambridge: Woodhead Publishing, 2019, pp. 41–59.

24.

Rather LJ, Jameel S, Dar OA, et al. Advances in the sustainable technologies for water conservation in textile industries. In: Muthu SS (ed.) Water in textiles and fashion. Cambridge: Woodhead Publishing, 2019, pp.175–194.

25.

Saint-Jalmes

Physical chemistry in foam drainage and coarsening. Soft Matter 2006; 2: 836–849.

26.

Turner

JD.

An introduction to foam finishing. Text Chem Color 1980; 12: 19–21.

27.

Tong

Shao

Zhang

, et al. An AHP-based water-conservation and waste-reduction indicator system for cleaner production of textile-printing industry in China and technique integration. Clean Technol Environ Policy 2012; 14: 857–868.

28.

Wang

Zhong

, et al. Foam properties and application in dyeing cotton fabrics with reactive dyes. Color Technol 2014; 130: 266–272.

29.

Smith

Determining optimum wet pickup in low add-on finishing. Am Dyest Rep 1985; 74: 13–17.

30.

Farias

LT.

Progress in chemical foam technology for dyeing applications. AATCC Rev 2013; 13: 36–41.

31.

Basyigit

Kut

Hauser

Development of multifunctional cotton fabric via chemical foam application method. Text Res J 2019; 90: 1–11.

32.

Hasanbeigi

Price

A technical review of emerging technologies for energy and water efficiency and pollution reduction in the textile industry. J Clean Prod 2015; 95: 30–44.

33.

Shang

Poon

, et al. Foam dyeing for developing the wash-out effect on cotton knitted fabrics with pigment. Res J Text Appar 2011; 15: 44–51.

34.

Schmid

Process for ungumming silk. Patent 848605-A, USA, 1907.

35.

Schmid

Apparatus for ungumming silk fabrics. Patent 831997, USA, 1906.

36.

Wang

Yang

, et al. Effect of silk degumming on the structure and properties of silk fibroin. J Text Inst 2019; 110: 134–140.

37.

Faber

LDR

Carroll

CJ.

Method of treating textile materials and the like. Patent 1948568, USA, 1934.

38.

Kumins

Jerome

Chase

VL.

Process of coloring textile materials. Patent 2971458, USA, 1961.

39.

Lister

GH.

Water conservation—an alternative to solvent dyeing?

J Soc Dyers Colour 1972; 88: 9–14.

40.

Walter

Bryant

Readshaw

RL.

Foams for treating fabrics. Patent 4099913-A, USA, 1978.

41.

Baker

Bryant

Camp

, et al. Foam finishing technology. Text Res J 1982; 52: 395–403.

42.

Clifford

FFT: foam finishing technology. Text Chem Color 1980; 12: 23–25.

43.

Zeiffer

DF.

Apparatus for applying foamed coating material to a traveling textile substrate. Patent 20020108568-A1, USA, 2002.

44.

Aurich

CW.

Apparatus and method of foam dyeing a traveling sheet of textile yarn. Patent 2013/02835.45-A1, USA, 2013.

45.

Aurich

Zeiffer

Neupert

HA.

Method and apparatus for dyeing cellulosic textile substrates with an inert leuco state dye and dyed product. Patent 1591578-A2, Germany, 2005.

46.

Zeiffer

Neupert

HA.

Apparatus and method for applying a foamed composition to a dimensionally unstable traveling substrate. Patent 7431771-B2, USA, 2008.

47.

Aurich

Zeiffer

Neupert

HA.

Apparatus for dyeing textile substrates with foamed dye. Patent 2008/147515-AI, Switzerland, 2008.

48.

Zeiffer

Aurich

Neupert

HA.

Controlled flow applicator. Patent 006814806-B2, USA, 2004.

49.

Cooke

TF.

Foam wet processing in the textile industry. Text Chem Color 1983; 15: 13–24.

50.

van Der Walt

GHJ

van Rensburg

NJJ.

Low-liquor dyeing and finishing. Text Prog 1986; 14: 1–50.

51.

Elbadawi

Pearson

JS.

Foam technology in textile finishing. Text Prog 2003; 33: 1–31.

52.

Roy Choudhury AK. Process control in finishing of textiles. In: Majumdar A, Das A, Alagirusamy R, et al. (eds.) Process control in textile manufacturing. Cambridge: Woodhead Publishing, 2013, pp. 363–427.

53.

Renpu W. Measures for putting a well into production. In: Renpu W (ed.) Advanced well completion engineering. 3rd ed. Oxford: Gulf Professional Publishing, 2011, pp. 417–523.

54.

Murray

Ettelaie

Foam stability: proteins and nanoparticles. Curr Opin Colloid Interface Sci 2004; 9: 314–320.

55.

Koehler

Hilgenfeldt

Stone

HA.

A generalized view of foam drainage: experiment and theory. Langmuir 2000; 16: 6327–6341.

56.

Wang

Guo

Zheng

, et al. Effect of temperature on foaming ability and foam stability of typical surfactants used for foaming agent. J Surfactants Deterg 2017; 20: 615–622.

57.

Thakore

Ren

Voytek

, et al. High temperature stability of aqueous foams for potential application in enhanced geothermal system (EGS). Oak Ridge, TN: Oak Ridge National Lab., 2021.

58.

Capponi

Flister

Hasler

, et al. Foam technology in textile processing. Rev Prog Color Relat Top 1982; 12: 48–57.

59.

Ross

Current methods of measuring foam. Ind Eng Chem Anal Ed 1943; 15: 329–334.

60.

Dawson

TL.

Foam dyeing and printing of carpets. J Soc Dyers Colour 1981; 97: 262–274.

61.

Wang

Guo

Zheng

, et al. Effect of temperature on foaming ability and foam stability of typical surfactants used for foaming agent. J Surfactants Deterg 2017; 20: 615–622.

62.

Shaoyu

Chaoxia

Liang

, et al . A novel strategy for realising environmentally friendly pigment foam dyeing using polyoxyethylene ether surfactant C14EO5 as a foam controller. Color Technol 2017; 133: 253–261.

63.

Calvert

Nezhati

A rheological model for a liquid-gas foam. Int J Heat Fluid Flow 1986; 7: 164–168.

64.

Cotton Inc. Foam applications on textiles. Technical Bulletin. Bulletin no. TRI 4009, 2011, Cary, North Carolina: Cotton Inc.

65.

Zhu

Song

Liu

, et al. Effects of foaming parameters on sized-foam properties. Text Res J 2015; 86: 2096–2105.

66.

Heller

Kuntamukkula

MS.

Critical review of the foam rheology literature. Ind Eng Chem Res 1987; 26: 318–325.

67.

Nakama

Surfactants. In: Sakamoto K, Lochhead RY, Maibach HI, et al. (eds) Cosmetic science and technology. Amsterdam: Elsevier, 2017, pp.231-244.

68.

Bureiko

Trybala

Kovalchuk

, et al. Current applications of foams formed from mixed surfactant–polymer solutions. Adv Colloid Interface Sci 2015; 222: 670–677.

69.

Zhu B, Cao X, Liu J, et al. Effects of foamers and stabilizers on foaming ability and stability of oxidized starch/polyacrylic acid size liquor in foam sizing. J Eng Fibers Fabr 2017; 12: 26–32.

70.

Georgieva

Cagna

Langevin

Link between surface elasticity and foam stability. Soft Matter 2009; 5: 2063–2071.

71.

Rosen MJ. Factors affecting the value of the CMC in aqueous media. In: Rosen MJ (ed) Surfactants and interfacial phenomena. New York: Wiley, 1978, pp. 120–121.

72.

Sarwar

Mohsin

Bhatti

, et al. Development of water and energy efficient environment friendly easy care finishing by foam coating on stretch denim fabric. J Clean Prod 2017; 154: 159–166.

73.

Gregorian RS, Bafford RA and Namboodri CG. The utilization of foams in the wet processing of textiles. In: Vigo TL and Nowacki LJ (eds) Energy conservation in textile and polymer processing. Washington, DC: ACS Publications, 1979, pp. 155–173.

74.

Bryant GM. Energy and related savings from controlled low wet pick-up application of textile chemicals and dyes via semistable foams. In: Vigo TL and Nowacki LJ (eds) Energy conservation in textile and polymer processing. Washington, DC:ACS Publications, 1979, pp. 145–154.

75.

Madhu

Pal

Low wet pick-up techniques in textile finishing. Man-Made Text India 2012; 40: 5–8.

76.

Bertoniere

King

WD.

Effect of scouring/bleaching, caustic mercerization, and liquid ammonia treatment on the pore structure of cotton textile fibers. Text Res J 1989; 59: 114–121.

77.

Ul-Haq

Nasir

Cleaner production technologies in desizing of cotton fabric. J Text Inst 2012; 103: 304–310.

78.

Hardin

IR.

Enzymatic scouring of cotton: effects on structure and properties. Text Chem Color 1997; 29: 71–76.

79.

Basto

Tzanov

Cavaco-Paulo

Combined ultrasound-laccase assisted bleaching of cotton. Ultrason Sonochemistry 2007; 14: 350–354.

80.

Saapan

Kandil

Habib

AM.

Liquid ammonia and caustic mercerization of cotton fibers using X-ray, infrared, and sorption measurements. Text Res J 1984; 54: 863–867.

81.

Perkins

Walker

RP.

Foam sizing. Text Res J 1982; 52: 547–554.

82.

Turner

Blanton

Kravetz

Foam mercerization. Text Res J 1982; 52: 73–76.

83.

Namboodri

CG.

Foam sizing of cotton and blend yarns: slashing trials. Text Res J 1986; 56: 87–92.

84.

Shang SM. Process control in dyeing of textiles. In: Majumdar A, Das A, Alagirusamy R, et al. (eds) Process control in textile manufacturing. Cambridge: Woodhead Publishing, 2013, pp. 300–338.

85.

Clark M. Fundamental principles of dyeing. In Clark M (ed) Handbook of textile and industrial dyeing: principles, processes and types of dyes. Cambridge: Woodhead Publishing, 2011, pp. 3–27.

86.

Chattopadhyay

Chavan

Sharma

JK.

Salt‐free reactive dyeing of cotton. Int J Cloth Sci Technol 2007; 19: 99–108.

87.

Asgher

Batool

Bhatti

, et al. Laccase mediated decolorization of vat dyes by Coriolus versicolor IBL-04. Int Biodeterior Biodegradation 2008; 62: 465–470.

88.

Lambert

Harper

RJ.

Single side crosslinking via foam finishing to produce garment dyeable cotton fabrics. J Coat Fabr 1990; 19: 169–180.

89.

Bhavsar

Giansetti

Maier Stelian

, et al. Superheated water hydrolyzed keratin: a new application as a foaming agent in foam dyeing of cotton and wool fabrics. ACS Sustain Chem Eng 2017; 5: 9150–9159.

90.

Berendt

H-U

Schafer

Process for dyeing or printing cellulose-containing textile material with vat dye foam. Patent 4613335-A, USA, 1986.

91.

Magda

Kamel

Shakra

, et al. Foam dyeing with vat dyes. Am Dyest Rep 1997; 86: 35–41.

92.

Malpass

Tharpe

Ethridge

MD.

Indigo dyeing process and apparatus and indigo dyed yarns and fabrics made thereby. Patent 10619292-B2, USA, 2020.

93.

Shakra

Hanna

Kharadly

EA.

Foam dyeing with reactive dyes and its effect on the fastness properties of dyeings. Am Dyest Rep 1989; 78: 60.

94.

Lammermann

Mees

Formaldehyde-free easy care finishing of cellulose-containing textile material. Patent 5352242-A, USA, 1994.

95.

Dehabadi

Buschmann

H-J

Gutmann

JS.

Durable press finishing of cotton fabrics: an overview. Text Res J 2013; 83: 1974–1995.

96.

Lee

Kim

HJ.

Durable press finish of cotton/polyester fabrics with 1, 2, 3, 4‐butanetetracarboxylic acid and sodium propionate. J Appl Polym Sci 2001; 81: 654–661.

97.

Zhang

Gong

Wrinkle-resistant finish of foam technology for cotton fabric. J Ind Text 2014; 43: 525–535.

98.

Rowland

Bertoniere

King

WD.

Durable press performance and reagent distribution from foam application of DMDHEU. Text Res J 1983; 53: 197–204.

99.

Yang

Perenich

Fateley

WG.

Studies of foam finished cotton fabrics using FT-IR photoacoustic spectroscopy. Text Res J 1989; 59: 562–568.

100.

Gonzales

Reinhardt

RM.

Foam finishing treatment of cotton fabrics with formaldehyde Part I: textile physical properties. Text Res J 1986; 56: 497–502.

101.

Gonzales

Reinhardt

RM.

Foam finishing treatment of cotton fabrics with formaldehyde: Part II: formaldehyde properties. Text Res J 1987; 57: 113–117.

102.

Gaan S, Salimova V, Rupper P, et al. 5 - Flame retardant functional textiles. In: Pan N and Sun G (eds) Functional textiles for improved performance, protection and health. Cambridge: Woodhead Publishing, 2011, pp. 98–130.

103.

Gregorian

Namboodri

Young

, et al. Foam application of phosphonium salt flame retardants. Text Res J 1983; 53: 148–152.

104.

Ferrero

Periolatto

Udrescu

Water and oil-repellent coatings of perfluoro-polyacrylate resins on cotton fibers: UV curing in comparison with thermal polymerization. Fibers Polym 2012; 13: 191–198.

105.

Ceria

Hauser

PJ.

Atmospheric plasma treatment to improve durability of a water and oil repellent finishing for acrylic fabrics. Surf Coating Technol 2010; 204: 1535–1541.

106.

Liu

Choi

C-H

Xin

JH.

Cotton fabrics with single-faced superhydrophobicity. Langmuir 2012; 28: 17426–17434.

107.

Xie

Wang

, et al. An effective and low-consumption foam finishing strategy for robust functional fabrics with on-demand special wettability. Chem Eng J 2021; 426: 131245.

108.

Song

Hou

, et al. Performance of foam and application in foam finishing of textile. AMR 2013; 821-822: 661–664.

109.

Wadsworth

Wey

P-S.

Effects of differential foam application of durable press and fluorochemical finishes to cotton fabric. J Coat Fabr 1988; 17: 152–166.