A Brief Discussion on Washing and Color Protection of Dark Natural Fiber Fabric Garments - Case Study of Mohok Washing Company

Abstract

As one of the industries supporting clothing and apparel, the washing and dyeing industry is an inseparable part of people's daily lives. In recent years, with the improvement of living standards, it has provided a good development prospect and broad market space for the washing industry.

The improvement of quality of life and the increase in spiritual needs have led people to have deeper demands for services. In addition to requiring the "quantity" of service, attention has also begun to be paid to the "quality" of service. However, with more use of textile printing and dyeing direct dyes and acid dyes, the color fastness and wash fastness of natural fiber fabric clothing are poor. Whether consumers wash at home or at laundries (factories), fading of dark natural fiber fabrics during washing is becoming increasingly common. This has caused many troubles for consumers and the washing and dyeing industry.

Keywords: natural fibers, color fastness, clothing classification, three-step method.

1 Introduction

1.1 Analysis of Natural Fiber Categories

[0001] Plant fiber clothing fabrics are mainly divided into two categories: cotton and linen. Pure cotton fabrics have the soft luster of natural cotton fibers, a soft hand feel, but poor elasticity and are prone to creasing. Linen fabrics are simple and natural, with a soft and bright luster, smooth hand feel, thick and stiff texture, relatively coarse fabric, uneven prickly feel to the touch, deeper creases after gripping and releasing, and slow recovery. Because plant fibers generally use direct dyes, the wash fastness is not high.

[0002] Animal fiber clothing fabrics are mainly divided into two categories: silk and wool. The main component of silk and wool products is animal protein, and their fabric luster is soft and natural, with a smooth hand feel, soft, full, crisp, and not easy to crease. Because animal fibers generally use acid dyes, the wash fastness is not high.

Industry insiders point out that with the trend of low wash fastness of clothing, industry practitioners should pay attention, formulate reasonable washing processes, and select appropriate washing auxiliaries to improve the quality and importance of clothing washing and color protection.

1.2  Current Problems with Wash Fastness

[0001] Wash fastness is one of the most important indicators of clothing. It depends on the interaction between the dye and the fiber as well as the solubility of the dye in water. For example, when dyeing, vat dyes and insoluble azo dyes enter the polymer matrix of the fiber, facilitating the formation of water-insoluble substances, so these dyes have good wash fastness. Reactive and chrome mordant dyes form covalent bonds with fibers and become wash fast. Some dyes, such as direct dyes and acid dyes, have poor wash fastness.

[0002] Direct dye solubility and loss are related to the water solubility of dye molecules. The sulfonic acid groups in the dye form hydrogen bonds with the fiber. When the dyed fabric is immersed in water, the hydrogen bonds are broken, and some swollen dye molecules leave the fiber and dissolve in water. In washing machines, agitation causes pigment from insoluble dyes to fall off fibers. The higher the washing temperature, the larger the bath ratio, the longer the time, and the more intense the agitation, the more dye is lost. Additionally, the presence of surfactants during washing greatly increases dye solubility from fibers. The main reason for dye removal is that pigments are lipophilic and can co-dissolve with the hydrophobic groups of surfactants, thus pulling the dye away from the fibers.

[0003] Acid dyes dye under acidic conditions, but after making into clothing, washing is done under neutral or weakly alkaline conditions. Under these conditions, the chemical attraction between dye and fiber molecules complicates the ability of dye molecules to migrate along the fiber lumen. For dyed animal protein fibers, the attraction between dye and fiber (and possibly between dyes) tends to keep dye molecules attached to fiber molecules rather than diffusing along fiber channels. The rate of dye desorption from fibers into alkaline buffer solutions decreases as the affinity between dye and fiber increases, and desorption rate also decreases with lower alkalinity. Therefore, fading easily occurs during washing.

[0004] Synthetic fiber fabrics cannot compare with natural fiber fabrics. With the improvement of people's living standards and technological progress, household washing machines and dryers have become very common. Some consumers, considering public health safety concerns, prefer to wash personal clothes at home. Because natural fibers are comfortable to wear, consumers are willing to buy clothing made of natural materials, so they are generally welcomed by consumers. However, natural fabrics also have disadvantages such as relatively poor strength, low color fastness, easy fading and color bleeding, easy wrinkling, easy yellowing, easy snagging, and difficulty in cleaning and maintenance after soiling, which cause great headaches for consumers. These drawbacks also cause great headaches for consumers.

2  Solutions to the Problems

2.1 Focus on clothing classification and select washing processes according to clothing types.

[0001] Clothing classification generally includes woolen (velvet) coats, suits, trousers, wool sweaters, scarves which are chosen for dry cleaning. Jeans, corduroy, faux fur, shirts, casual wear, sweatshirts, sportswear, garments with light and dark color combinations, garments with bead and rhinestone combinations, silk products, and bedding textiles are chosen for wet cleaning.

[0002] Currently, there are generally two washing methods for natural fiber fabrics at home and abroad. One is dry cleaning, which uses volatile organic solvents. Organic solvent The agent (main components are tetrachloroethylene and hydrocarbon solvents) performs dry cleaning on fabric stains. During dry cleaning, about 95% of the solvent is recovered through a recovery device during solvent drying, and the remainder naturally evaporates into the air. This kind of method, although effective at removing oil stains and some inorganic stains, cannot clean all stains completely. However, these solvents have a pH of about 7-8.5, which is weakly alkaline, causing slight fading on dark fabrics after washing and leaving a solvent odor.

[0003] Another method is wet cleaning, using water as the washing medium and water-soluble detergents. Detergents commonly available on the market are generally weakly alkaline. After washing, natural fibers commonly experience fading after washing, color differences, mismatched colors, yellowing, loss of luster, and other issues. Moreover, for some combinations of light and dark fabrics, leather and fabric mixed garments, and brightly colored clothing, the washing effect is very unsatisfactory; acidic raw material detergents also have the problem of insufficient oil stain removal. There is also the issue that acidic detergents do not effectively remove oil stains.

[0004] For natural fabric garments prone to fading, when choosing wet cleaning, a three-step washing method is used. The first step is to use a dry powder spray to remove oil stains. The biggest feature of the dry powder spray is oil removal without fading. After spraying, let it sit for about 5 minutes before machine or hand washing. Choose detergents containing fiber color-fixing components, ideally with a pH between 5.5 and 6. Add 15-20 ml of detergent per kilogram of fabric. Generally, washing at room temperature without heating is sufficient. After drying and ironing flat, if there is color difference or the color is not bright enough, lightly spray a color restoration agent to achieve the ideal cleaning and care effect.

3  Self-evaluation, pilot effect, and benefits achieved

The three-step wet cleaning method for color protection of dark natural fiber garments was piloted by the headquarters washing team starting in March 2024 and promoted to all front-store and back-factory stores by September 2024 to popularize the three-step wet cleaning method. The standardized pilot work of the Mohawk three-step wet cleaning method will scientifically, effectively, and steadily promote the standardization of the Mohawk three-step wet cleaning method, making Mohawk Laundry Chain more standardized, refined, and professional. It can effectively ensure the implementation of process measures, promote the comprehensive development of Mohawk Laundry Chain's economic benefits and quality. The process implementation has achieved the following economic and social brand benefits:

1. Improve the three-step wet cleaning work mechanism. Integrate the "three-step wet cleaning standardization" deeply with Mohawk Laundry Chain, explore and formulate a set of standards applicable to laundry chains, aiming to establish a clear and followable standard specification system to form a good operating mechanism of "managing by system and acting according to procedures."

2. Enhance enterprise service capability. Through the pilot of the three-step wet cleaning standardization, promote the institutionalization, standardization, and scientific decision-making of Mohawk Laundry Chain's work, establish an open, transparent, and standardized enterprise power operation mechanism, improve the supervision and restraint mechanism of enterprise management, performance evaluation system, and accountability mechanism, strengthen the technical team's work style and efficiency, standardize Mohawk Laundry Chain, improve the quality and ability of the management team, regulate power operation by system. Especially, it makes Mohawk Laundry Chain's work more efficient, standardized, and easier to operate, helping to improve Mohawk Laundry Chain's capacity and service level for batch color-fading garment color protection washing from garment factories. Mohawk Laundry Chain's technical service capability is strengthened, customer service capability and industrial agglomeration ability continuously improve, and social economy achieves sustainable and healthy development.

3. Reduce enterprise management costs. Through the pilot of the three-step wet cleaning standardization, the rewash rate has been reduced, garment output efficiency improved, washing costs lowered, and Mohawk Laundry Chain's work efficiency increased. At the same time, by establishing an independent three-step wet cleaning standardized operation process, improving and perfecting the segmented washing process, implementing comprehensive standardization, transparent process, and easy employee operation, fully promoting accident performance evaluation, management cost control is strengthened institutionally, effectively improving management efficiency.

4. Accumulate pilot experience. The washing team of the three-step wet cleaning standardization took the lead in trial and exploration, actively applying standardization concepts, improving workshop technical R&D capabilities, promoting formula industrialization with practical results, driving enterprise economic benefit development, and providing the whole industry with new process experience and models that are feasible, replicable, and promotable.

Conclusion

The washing industry encounters various challenging issues every year, such as new styles and fabric materials. With continuous industry development and social progress, and the increasing material and spiritual needs of people, the requirements for improving washing technology service capabilities will also continuously increase. In this article, taking Mohawk Company as an example, I detailed how a washing company performs the three-step wet cleaning method for dark natural fiber garments. I deeply realize that as a laundry worker, only by continuously exploring washing process methods in practical work, formulating standards, and tailoring washing processes to the actual enterprise situation can the enterprise develop healthily and orderly, ultimately achieving sustainable business operation.

Author of this article: Hu Cunkai, Technical Director of Wenzhou Mohawk Laundry Service Co., Ltd.

References

1. Q/MHK001-2020( Mohawk Standardized Management)
2. GB/T24421-2009( Guidelines for Standardization of Service Organizations )
3. GB/T15624-2011( Guidelines for Service Standardization)
4. CN 112795437 Brilin Technology (Beijing) Co., Ltd.