The progress of modern science and technology not only brings convenience to human life, but also brings many potential hazards. The living environment is getting worse and worse, electromagnetic radiation is lurking everywhere, and harmful bacteria are spreading everywhere. As a kind of high-performance functional fiber, silver-plated fiber has attracted worldwide attention for its unique functions of antibiosis, deodorization, anti-electromagnetic radiation, antistatic and body temperature regulation. Now it has been widely used in underwear, home textiles, special clothing, medical care, sports, military equipment and other fields, and has become a hot spot in contemporary functional fiber research and product development.
1 History and present situation of silver-plated fiber
1.1 Technology of metal plating on fiber
Tracing back to the history of silver-plated fiber, as early as last century, Germany, Israel and the United States took the lead in developing copper, nickel, silver and other metals on fiber, and developed related products. Since then, Japan, Russia and China have also invested in this research and development, and now there are many related patents [1-2 At present, the application of silver-plated, copper-plated and nickel-plated fibers in radiation-proof textiles and clothing has become unique. Metal plating technology on fiber is mainly divided into the following three categories [3]:
Electroless plating: metal ions are reduced and deposited on the surface of base fabric to form a metal film by using reducing agent in chemicals. Its biggest disadvantage is that wastewater containing heavy metal ions will be produced in the process of electroless plating production, which will be restricted by environmental protection.
electroplating: metal ions in the solution are reduced by current to form a metal film on the surface of the coated fiber substrate.
vacuum plating: metal is deposited and piled up on the surface of textile materials in atomic or molecular state in vacuum to form nano-grafted metal films, thus realizing the surface functionalization of textile materials. It includes vacuum evaporation, vacuum ion plating and vacuum sputtering. Vacuum coating technology is the most advanced surface treatment technology in the world at present, and the metallization effect on the surface of textile materials is the most ideal.
1.2 varieties and preparation of existing silver-plated fibers
the largest brand of silver-plated fibers in the world is x-static of Noble Fiber Technologies in the United States. At the beginning of its birth, electroless plating technology was adopted, that is, a layer of pure silver was plated on the surface of polyamide. At present, the fiber has been authorized by more than 1 manufacturers to put into production, but the price has been high, with sales of more than 4 million US dollars last year. In addition, Sauquoil, a sister company of Noble, also developed a silver-plated fiber called Contax.
The research on silver-plated fibers in Japan is also very active. TOYOSHIMA & In 1999, CO.,LTD developed silver-plated polyester fiber with the trademark μ-func. It is made by coating a transparent polyester film (9μm in thickness) with pure silver (about 1μm in thickness), covering it with a layer of polyester film with the same thickness, and then cutting it into thin strips with a width of 23μm or 15 μ m. Its structure is shown in Figure 1. In addition, Mitsubishi Materials Company developed and manufactured silver-plated polyester fiber AGposs in 21, with a fiber diameter of 15-25 μ m and a silver thickness of .1μm [4], as shown in Figure 2.
The silver-plated fiber developed by domestic Jinan Lisite Fiber Co., Ltd. uses multi-target magnetron sputtering rubbing coating technology and composite electroplating technology to deposit silver on polyester or nylon, and applied for an invention patent in 24 [5]. It is based on the fact that the chemical fiber substrate is not conductive. Firstly, a layer of silver film is sputtered on the fiber surface by vacuum plating, and then silver is plated by electroplating. This process has the advantages of uniform coating, strong adhesion and washing resistance.