Human beings are facing an increasingly deteriorating ecological environment, looking forward to the emergence of natural therapies that can restore the body's healing ability; looking forward to the advent of functional textiles that can restore health and enhance immunity. The functional textiles referred to in this article are those that use extracts from natural medicinal plants as functional agents, processed into textiles to achieve effects such as antibacterial, deodorizing, moisturizing, moisture absorption, mothproofing, improving skin feel, anti-allergy, and treating dermatitis. It can be said that this is a health-preserving and comfortable processing method.
　　
　　1 Traditional natural plants that can extract functional agents
　　
　　1·1 Aloe Vera
　　
　　The main component of aloe vera is aloin (a phenolic component), which is the bitter juice from the epidermis and inner side of aloe vera leaves. It has anti-inflammatory and anti-mutagenic effects, with no side effects on the human body. The Japanese company Toyobo has products in its "Clean Revolution" series that use aloe vera extract as an antibacterial agent. The antibacterial deodorant Berbtrit launched by the Japanese company Daiwa contains extracts of aloe vera, mugwort, and purple perilla. This combination of natural medicinal plants not only has antibacterial effects but also provides certain care for the skin.
　　
　　1·2 Mugwort
　　
　　Mugwort is a perennial herbaceous plant belonging to the Asteraceae family. Its main components include 1,8-eucalyptol, α-selinene, acetylcholine, and choline, which possess antibacterial, anti-inflammatory, anti-allergic, and blood circulation-promoting properties. The Evercare product from the Japanese company Unitika is created by adsorbing mugwort extract onto porous inorganic microcapsules. Additionally, in Japan, there are fabrics dyed with mugwort that are used to make pajamas for patients suffering from specific reactive dermatitis.
　　
　　1·3 Watercress
　　
　　Watercress is a perennial herbaceous plant of the Brassicaceae family. The medicinal components of the leaves and stems mainly contain decanoyl acetaldehyde, methyl nonyl ketone, and lauric acid. It has strong antibacterial effects against Staphylococcus and filamentous bacteria. Due to its high safety, it is used as a health-preserving and comfortable processing agent for fabrics. The natural antibacterial agent Herbcare from the Japanese company Daiwa and the antibacterial agent Paraglas from the Japanese company Patatiumuu both contain watercress extract.
　　
　　1·4 Licorice
　　
　　Licorice is a perennial herbaceous plant of the legume family, mainly produced in China, Afghanistan, and other regions. It is commonly used as a medicinal herb in traditional Chinese medicine and has long been recognized as a medicinal plant. The main component of licorice is glycyrrhizin, which is 150 times sweeter than sucrose. It generates glycyrrhetinic acid, glucuronic acid, and flavonoid glycosides upon acid hydrolysis. It has anti-inflammatory, anti-mutagenic, anti-ulcer, and detoxifying effects. Its toxicity is low, making it safe for the human body. The antibacterial deodorant Amaxan from the Japanese company Daiwa is made using the natural component glycyrrhizin acid dipotassium, characterized by its anti-allergic and anti-inflammatory properties.
　　
　　1·5 Tea Leaves
　　
　　Tea leaves contain various chemical components, mainly polyphenolic compounds, alkaloids (caffeine), catechins, etc. Studies have shown that catechins inhibit microorganisms such as Streptococcus and Staphylococcus aureus. They can also inhibit the activity of tyrosinase. In addition, they have many medicinal functions such as antiviral, antifungal, detoxifying, and anti-cancer effects. The Japanese company "Fukubou" extracts catechins from natural tea leaves to process cotton fabrics, producing products with high antibacterial and deodorizing functions called "Qiebafulanxiu"; the "Daiwa" company also uses catechins to process cotton products with deodorizing and antibacterial functions called "Katakan Kulin".
　　
　　1·6 Pomegranate Peel
　　
　　Pomegranate is a deciduous shrub of the Punicaceae family, originally from Iran. The fruit peel can be used medicinally, and its extract has the ability to inhibit collagenase activity, which can develop high-performance ecological antibacterial fabrics. Its pigment components can be used as direct dyes for cotton fabrics and for antibacterial finishing. Experimental results from the Tokyo Metropolitan Institute of Public Health indicate that when the dyeing concentration is above 50% (based on fabric weight), pomegranate dyeing meets the antibacterial strength and durability standards set by the Hygiene Processing Association. Additionally, in terms of dyeing fastness, it meets the dyeing fastness standards for JIS bath towels. Therefore, Japan is developing pomegranate as an ecological antibacterial finishing agent that does not pollute the environment.
　　
　　2 Extraction technology and safety testing methods for effective components of medicinal plants
　　
　　2·1 Application of molecular distillation
　　
　　The effective components of certain medicinal plants refined by general distillation methods may undergo polymerization or decomposition, leading to decreased quality and yield, and increased costs. Especially for components with higher boiling points or strong heat sensitivity, molecular distillation must be used to process them to obtain high-quality products.
　　
　　Characteristics of molecular distillation: 1) The vaporization temperature during distillation is low, even below the boiling point under corresponding pressure. 2) Due to the special structure of the equipment, heating and condensation occur within a single shell, minimizing unnecessary resistance, allowing for extremely low operating pressure during distillation. 3) The distance that material molecules travel from the vaporization surface to the condensation surface is very short, so the heating time is very brief, generally within 1 minute, resulting in very few opportunities for material damage. For example, refined oils such as patchouli oil and angelica oil.
　　
　　2·2 Application of carbon dioxide extraction technology
　　
　　Supercritical fluid extraction (SFE): Its working area generally has a pressure of 200-300 Bar and a temperature between 40-80°C. The properties of CO2 fluid are between liquid and gas, with strong solubility, and its viscosity is similar to that of gas, providing high mass transfer capability. It is suitable for extracting substances like hops used in beer production and for removing caffeine from coffee or tea leaves. Caffeine in coffee can be reduced from the original 3% to 0.2%, making it suitable for people who have difficulty sleeping while the extracted caffeine is also a good natural medicine, achieving a dual benefit. In recent years, China has also introduced several sets of equipment from Germany to extract products such as ephedrine, curcumin, and glycyrrhizin for export.
　　
　　2·3 Application of chromatographic column separation method
　　
　　This device can separate mixed compounds with boiling points below 300°C, especially those with very close boiling points and relative volatility less than 1.2. It can separate isomers, trace impurities, and some azeotropic mixtures, which are difficult to separate using distillation, liquid extraction, and fractional crystallization.
　　
　　Application of 2·4 Membrane Separation Technology
　　
　　Ultrafiltration: Used to filter substances with a particle size of 1nm, can filter some viruses, bacteria, proteins, concentrated fermentation liquids, etc., with an operating pressure between 100~1000kPa.
　　
　　Reverse Osmosis Filtration: Filters ionic substances ranging from 1 nm to 1 μm, capable of separating sugar molecules, salt molecules, and certain metal ions from the solution, and can be utilized for seawater desalination.
　　
　　2·5 Routine Testing Methods for the Safety of Herbal Medicines
　　
　　Natural substances do not mean safety; many herbal medicines are toxic. For herbal medicines that can be used for textile finishing, refer to the pharmacopoeia and relevant regulations on the application of herbal medicines in cosmetics. Safety tests must be conducted before using herbal extracts that are unfamiliar with toxicity, irritation, and allergenicity. Routine tests include: 1) Acute oral toxicity test. The test animals are white mice, and the toxicity value is expressed as the 50% lethal dose (LD50). 2) Skin irritation test, using rabbits as test animals, examining the rabbit's skin for inflammation, erythema, edema, and other reactions to the sample. 3) Allergenicity test, using mice as test animals, observing skin changes after injection.
　　
　　3 Technology and Product Development of Natural Antibacterial Finishing Agents for Textiles
　　
　　3·1 Finishing Technology of Natural Antibacterial Agents
　　
　　3·1·1 Microencapsulation Technology Currently, microencapsulation technology is widely used, which involves wrapping one or more active ingredients of herbal medicines in micro-particle capsules, then fixing them in the fibers of the fabric, making it a health care fabric. Some capsules in the fibers burst upon contact with the skin, releasing fragrances, insect repellents, and antibacterial agents, thus exerting their health care effects. For antibacterial and insecticidal microencapsulated functional agents, the composition and thickness of the wall material can usually be changed to control the release rate of the microencapsulated antibacterial agents, extending their durability. During application, microcapsules can be fixed on textiles through coating processing or used together with adhesives. If the durability is not long, textiles can also be impregnated to burst the microcapsules, allowing the antibacterial agents to penetrate into the textiles and immediately exert antibacterial or insecticidal effects.
　　
　　3·1·2 Ultrasonic Technology When ultrasound propagates, it causes particles in elastic media to oscillate and transmits energy through the medium in the direction of ultrasound propagation. In liquids, molecules undergo compression and rarefaction longitudinally, and low-pressure areas will form cavities or bubbles. These cavities expand and eventually collapse violently, generating shock waves, a phenomenon known as cavitation. During the cavitation process, extremely high pressure and temperature can be generated in a very small range of the solution, causing significant local agitation, which is an important reason for most physical and chemical effects produced by ultrasound.
　　
　　In water media, the maximum cavitation effect occurs at around 50°C, so the effect of using ultrasound in dyeing and finishing processes is better than that of low-temperature processing. Plant pigments with health care functions can be used for dyeing and finishing textiles using ultrasonic technology. Among the plant dyes used in ancient textiles, many varieties have health care effects on the human body, as recorded extensively in the "Compendium of Materia Medica"; plant dyes are truly environmentally friendly dyes.
　　
　　Example 1: Lithospermum, a perennial herb of the Boraginaceae family, states in the "Compendium of Materia Medica": "Lithospermum, its function is to cool the blood, benefit the large and small intestines, therefore, for those with bean rashes that are about to appear, blood heat and toxicity, and constipation, it is advisable to use it." Traditional Chinese medicine often uses Lithospermum to treat heat sores, fetal toxins, constipation, hematuria, and other heat toxicity symptoms. Modern medicine has proven that Lithospermum has various pharmacological effects such as antibacterial, anti-inflammatory, antiviral, and anti-tumor, and is clinically used to treat acute and chronic hepatitis, pulmonary tuberculosis, dermatitis, eczema, psoriasis, etc., with significant efficacy.
　　
　　Lithospermum quinone is bright red, and acetyl lithospermum quinone is purplish-red. If clothing made from Lithospermum-dyed fabric is made into underwear for the elderly, it should be beneficial for the skin health of the elderly. Similar plants with antibacterial effects include madder and logwood.
　　
　　Example 2: Indigo, a perennial herb of the family Fabaceae, its chemical component is mainly indican, which exists in the leaves and stems, and is produced by fermentation. The leaves of indigo can also be used as Da Qing Ye in medicine, with effects similar to those of Polygonum tinctorium and Isatis tinctoria. The root of indigo is called "Nan Ban Lan Gen" in medicine, which has the same medicinal function as the "Bei Ban Lan Gen" made from Isatis root. Traditional Chinese medicine believes that Da Qing Ye has the functions of clearing heat, detoxifying, and cooling the blood, and can be used to treat oral ulcers, colds, and erysipelas. Modern medicine has confirmed that Da Qing Ye has a strong killing effect on various dysentery bacilli and meningococci, with significant efficacy and no drug resistance produced by bacteria. Ban Lan Gen has a medicinal value similar to that of Da Qing Ye.
　　
　　The leaves, roots, and stems of various blue grasses can be used in medicine, and indigo dye itself is also a traditional Chinese medicine. The "Compendium of Materia Medica" states: "Indigo is made from blue and lime, its taste and smell are slightly different from blue, but its functions of stopping bleeding, detoxifying, and killing insects seem to surpass blue." Indigo is commonly used by the Miao, Yao, Dong, and other ethnic minorities in Southwest China to produce indigo dye. The Yao ethnic group also has a group of merchants called "Lan Dian Yao" who specialize in planting indigo for dyeing. These ethnic minorities live year-round in the humid and hot deep mountain forests, and a garment dyed in indigo may be their best health garment against diseases and sores.
　　
　　3·1·3 Plasma Technology The application of plasma technology in dyeing and finishing mainly includes two aspects: surface modification of fibers and graft polymerization. In recent years, some have applied plasma treatment to the functional finishing of textiles, the principle being to first treat the fibers with plasma to activate them, and then carry out relevant finishing, or directly induce reactions between the fibers and finishing agents using plasma for fixation treatment. It is recommended that herbal antibacterial finishing agents be tested using the above two methods for application on textiles.
　　
　　3·1·4 Nanotechnology Nanomaterials are brand new ultra-fine solid materials. It has been reported that some have begun to apply nanotechnology to herbal medicines, allowing nano-sized Fe3O4 to coat natural medicines to reach the areas needing treatment under the influence of a magnetic field. Research in this area is still in its infancy and deserves further exploration.
　　
　　3·2 Development of Health Care Antibacterial Textiles
　　
　　1· Microcapsules made from cedar alcohol and cypress alcohol in Japan are used to treat pure cotton fabrics, such as quilts, fabrics, underwear, knitted shirts, baby quilts, bed sheets, and towels, so that these textiles have the function of treating allergic dermatitis and alleviating itching, and have good wash resistance.
　　
　　2. Microcapsules made from mugwort extract by Takase Dyeing Co., Ltd. in Japan are used for special coating finishing on cotton or nylon fabrics, giving bedding, pajamas, and shirts antibacterial and deodorizing functions, which is particularly valuable for people suffering from eczema, prickly heat, and other dermatitis and skin allergies. The number of microcapsules exceeds 2 million/m2 and can withstand at least 50 home washes.
　　
　　3. Extracts from aloe vera, licorice, and plantain are used for moisturizing, antibacterial, and deodorizing finishing on feather bedding fabrics, bed sheets, sweatpants, and pajamas, ensuring safety, low irritation, and good wash resistance.
　　
　　4. Development of textiles for the elderly. As people age, their immunity decreases and the incidence of diseases increases. From both physiological and psychological perspectives, clothing should be comfortable and easy to move in, while also keeping up with trends in style and color. Especially for the frail elderly, clothing should also have antibacterial, health care, and multifunctional properties.
　　
　　4 Conclusion
　　
　　1. China has rich plant resources, and the ancient people have a long history of developing and utilizing medicinal plant resources; the use of herbal medicine, including Han prescriptions and secret recipes, has been tested over thousands of years. By using modern science and technology to explore and organize this valuable heritage, it can continue to benefit humanity. Therefore, using natural functional agents is an optimized and environmentally protective dyeing and finishing technology.
　　
　　2. With the rapid development of science and technology, dyeing and finishing technology is facing many changes. Accelerating the application of high-tech achievements will open up broader fields for textile dyeing and finishing, especially the demand for pollution-free "green" processing to produce "clean" textiles that are beneficial to health.
　　
　　3. Extracting effective components from ancient natural plants and transferring their functions to fibers, fabrics, bedding, and other textiles can moisturize the skin and provide antibacterial and deodorizing effects, benefiting both physical and mental freshness and promoting longevity.
　　
　　References
　　
　　1 Li Huiqin et al. Natural Antibacterial Finishing Agents. Journal of Textile Science, 2002(2):50~54.
　　
　　2 He Zhongqin, translated. Application of Natural Finishing Agents on Fabrics. Foreign Silk, 2002(2):13~17.
　　
　　3 He Zhongqin, translated. Testing Antibacterial Fabrics with Plant Pigments. Dyeing and Finishing Translation Series, 1998(2):96~102.
　　
　　4 Qin Weiting et al. Progress in Health Care and Comfort Processing Using Natural Functional Agents. Shanghai Dyes, 1998(2):45~47.
　　
　　5 He Zhongqin, translated. Waterless Dyeing with Supercritical Carbon Dioxide. Dyeing and Finishing, 1999(2):5~8.
　　
　　6 He Zhongqin, translated. Health Care and Comfort Finishing with Natural Functional Agents. Dyeing and Finishing Translation Series, 1998(2):63~73.
　　
　　7 Yu Wangmiao et al. Nanomaterials and Their Applications in the Textile Industry. Journal of Donghua University, 2001(12):121~127.