The application of nano-silver materials to the field of textile functional finishing and the development of multi-functional, high-value-added fabrics will create huge economic and social benefits in the future textile industry. Nano-silver is a new type of nano-material that is under in-depth research and rapid development. It has broad application prospects in the textile industry due to its broad-spectrum and long-lasting anti-bacterial properties/anti-electromagnetic radiation properties/conductivity and absorption of some ultraviolet rays.
Application in natural fiber yarn and fabric
The fabrics made of natural fibers have good moisture absorption and are mostly porous fibers, which can provide enough water for the growth of bacteria. At the same time, the surrounding environment can also provide oxygen for the growth of bacteria and promote the reproduction of bacteria. Nano-silver has broad-spectrum and long-lasting antibacterial properties. At present, the antibacterial application of nano-silver in natural fibers is mainly for yarns and fabrics, and the antibacterial function is mainly obtained through finishing.
Nano-silver antibacterial finishing of yarn is generally aimed at cotton yarn or wool. For example, on the basis of puffing and pretreatment of cotton yarn with sodium hydroxide, tannic acid-reduced silver ammonia solution is used to load nano-scale silver particles in the micro gaps of the fiber to make The nano-silver particles and fibers are loaded on the yarn through coordination bonds, so that the silver-loaded cotton yarn has good antibacterial and washing resistance.
Under acidic conditions, using nano silver sol and acid dyes to dye wool yarns and antibacterial finishing at the same time, not only can improve the dye uptake, color fastness and flexibility of wool yarns, but also make wool yarns have good antibacterial properties.
According to reports, some scholars now use the reducibility and stability of the fabric itself to reduce the nano-silver particles in situ on the fabric, so that the fabric has good antibacterial and washing resistance. For example, Ma Tingfang uses the reducibility and dispersibility of cellulose macromolecules to reduce the silver nitrate solution in situ to prepare nano silver antibacterial cotton fabric, which has excellent antibacterial effect and washing resistance. After 20 cycles of washing, the antibacterial fabric will affect the large intestine. The inhibitory rates of Bacillus and Staphylococcus aureus are still as high as 98.5% and 94.3%, respectively. Majid Montazer and others also successfully used the reducibility and stability of cellulose to reduce Torrance reagent (silver ammonia solution) to synthesize nano silver. After the fabric treated with nano silver was washed for 30 times, the antibacterial performance was almost unchanged.
In addition, some scholars compound nano-silver with other substances, using inorganic-organic compounding method or inorganic-inorganic compounding method, to prepare compound such as nano-silver/polysaccharide quaternary ammonium salt (HACC), nano-silver/titanium dioxide, etc. Compound, and then padding and finishing the fabric to obtain functional textiles with multiple functions. Wang Haiyun prepared silver-loaded nano-TiO2 antibacterial agent in an inorganic-inorganic compounding method and used it for the finishing of cotton fabrics, so that the cotton fabric obtained the dual antibacterial functions of silver ion elution antibacterial and TiO2 photocatalytic antibacterial, and two kinds of antibacterial The effects promote each other, making the antibacterial effect far better than a single antibacterial agent with the same content.
Application in synthetic fibers and fabrics
Three types of synthetic fibers such as nylon, acrylic, and polyester are widely used. At present, the application research of nano-silver in synthetic fibers is mainly aimed at these three types of fibers and fabrics. The manufacturing of synthetic fiber functional fabrics mainly includes two methods: spinning functional fibers and finishing, specifically including blending spinning method, dipping (rolling) method and magnetron sputtering method. The direct-spun functional fiber has a long-lasting effect, but the technology is complex and the cost is high; the finishing agent is simple and convenient to use, and is suitable for most fiber textiles. The cost is low, but the washing resistance is relatively low.
(1) Blending spinning method
The blending spinning method is to add nano silver particles in the fiber manufacturing process to blend and spin the fiber to make the final fabric have corresponding functions. The blending spinning process has no pollution to the environment and is widely used. Zhang Hua uses ultra-fine hemp rod core powder to prepare nano silver particles and spun them into antibacterial multifunctional nylon. When the powder content is 2%, nylon fiber not only has excellent antibacterial properties, high strength, and good elasticity. , It also has the ability of far-infrared emission and negative oxygen ion release, and the spinnability also meets the requirements.
The antibacterial polyester masterbatch is prepared by blending the silver-loaded nano-zinc oxide antibacterial agent treated with T-aminopropyl triethoxysilane and polyester, which is added to the polyester skin layer, and the core-type antibacterial polyester is produced by spinning. This fiber has excellent antibacterial properties, and the sterilization rate of Escherichia coli and Staphylococcus aureus is above 99%.
(2) Dipping (rolling) method
Although the blending spinning method is environmentally friendly, it is difficult to prepare a spinnable spinning solution. In contrast, the dipping (rolling) process is relatively simple. Yu Qiaozhen treated the nano-silver particles to polyester fabrics by dipping, and studied its effect on the antistatic properties of the fabrics, and found that nano-silver treatment can effectively improve the antistatic capabilities of polyester fabrics; and different treatment methods have endless effects on the fabrics. Similarly, for example, the effect of the one-bath method in which nano-silver particle treatment and dyeing are performed at the same time is significantly better than the two-step method in which dyeing is followed by finishing.
Some researchers have explored a new type of finishing method that allows nano-silver particles to be bonded to the surface of the fiber through chemical bonding, so that the bond between nano-silver and the fiber is stronger. For example, the researchers amidoxim part of the acrylic fiber to make the fiber surface with chelating groups, which can be complexed with silver ions, and then use formaldehyde solution to reduce the silver ions to obtain nano-silver composite acrylic fiber. The killing rate of Staphylococcus aureus and Bacillus subtilis exceeds 99.99%, the antibacterial performance is good, and the original physical properties of the fiber have no obvious changes.
(3) Magnetron sputtering method
In order to avoid the waste liquid disposal problem of the dipping (rolling) method, some researchers used the radio frequency magnetron sputtering method to sputter nano-silver film on the surface of the fabric. The magnetron sputtering method is to charge a proper amount of argon in a high vacuum, and apply a DC voltage between the cathode (columnar target or flat target) and the anode (the wall of the coating chamber) to ionize the argon gas, and the argon ions are accelerated and bombarded by the cathode On the surface of the cathode target, the atoms on the surface of the target are sputtered and deposited on the surface of the substrate to form a thin film. This method has the advantages of strong bonding force between the coating layer and the substrate, and the coating layer is dense and uniform.
Application in industrial textiles
The application objects of nano-silver in industrial textiles are mainly non-woven fabrics, laminated composite fabrics and composite materials.
(1) Application in non-woven fabrics
The use of nano-silver to finish the non-woven fabric can obtain antibacterial properties and anti-electromagnetic radiation properties, which can be widely used in medical, sanitation, automotive interiors, electromagnetic shielding materials and other fields. Similar to synthetic fibers, the nano-silver finishing methods of non-woven fabrics also include blending spinning method, dipping (rolling) method and magnetron sputtering method, the principle of which is the same as described above. Hong Jianhan uses magnetron sputtering at room temperature to deposit nano-silver films on the surface of polyester spunbonded nonwovens to make the fabrics resistant to electromagnetic radiation. As the thickness of the nano-silver films increases, the shielding effect of electromagnetic waves is enhanced. This method expands the application field of nonwoven fabrics, and can be used to develop antistatic materials, conductive materials, electromagnetic shielding materials and fiber sensors.
The nano silver antibacterial agent is highly uniformly dispersed and implanted in the spinning solution to blend and spin, so that the fabric can obtain higher stability, antibacterial performance and washing resistance, and then obtain nano silver antibacterial spunlace nonwoven rolls and nano silver Antibacterial needle punched non-woven fabric rolls.
Its most extensive application field is the production of medical and sanitary products, such as nano-silver antibacterial masks, antibacterial wipes, medical bed sheets, medical wipes, etc. The latter’s market applications are also very broad, such as automobile compartment/indoor air conditioning antibacterial filter media, clothing linings, etc. , Antibacterial insoles, shoe materials, etc.
Application in laminated composite fabric
Laminated composite fabrics are ideal materials for civilian sportswear, cold-proof clothing, field work clothes, military combat uniforms, labor protective clothing and other products. The nano-silver finishing of composite laminated fabrics is mainly achieved by dipping or blending spinning. Researchers at Zhejiang Sci-Tech University used a cross-shaped cross-section polyester fiber material containing nano silver particles as an antibacterial modifier as the outer layer of the fabric, and combed cotton yarn with better moisture absorption as the inner layer of the fabric, using the changes in the fabric structure , Combined with advanced finishing technology, the fabric has multiple functions such as moisture absorption, perspiration, and antibacterial.
(3) Application in composite materials
The silver/polymer nanocomposite material not only has the excellent characteristics of nano silver and polymer, but also gives the material some new functions, so that it has broad application prospects in many fields such as textiles, electronics, and biomedicine.
As a new type of material, nano-silver is used in many fields, especially the textile industry is closely related to people’s lives, which has aroused the interest of many researchers. At present, the application of nano-silver in the textile industry is mainly to obtain antibacterial, antistatic, and anti-electromagnetic radiation functions. As people’s requirements for textile products increase, nano-silver will be increasingly used in functional fabrics, and its application prospects in the textile industry will become broader.