New antibacterial finishing technology for textiles

Antibacterial finishing technology is a very wide range of marginal subjects, involving dyeing and finishing, chemical engineering, medicine, microbiology and many other disciplines.The application of antibacterial finishing agent on textiles can not only cut off the route of transmission and reproduction of harmful microorganisms such as bacteria, fungi and molds, but also prevent odor, color spots and health problems caused by them.

Usually, antibacterial finishing refers to a method of applying antimicrobial agents to fibers and fixing them in textiles by dipping, rolling, coating or spraying in the process of textile printing and dyeing.With the development of textile technology, plasma technology, vacuum sputtering technology and nano technology are widely used in antibacterial finishing of textiles.

Plasma antibacterial finishing

Using plasma surface treatment to obtain antibacterial effect is a new technology of surface antibacterial modification.Ion implantation, ion beam assisted deposition (IBAD) and plasma immersed ion implantation deposition (piii-d) are the main technical methods for obtaining antibacterial properties of materials.

Ion implantation is a method of accelerating high-energy ions into solid surfaces under vacuum conditions.By injecting some antibacterial elements such as Ag and Cu on the surface of textile materials, the metastable phase or precipitation phase can be formed and the antibacterial properties can be obtained.The method has the advantage of solving the connection problem between coating surface and substrate prepared by other processes.Ion beam assisted deposition is a kind of material surface modification technology which integrates ion implantation and thin film deposition.It means that at the same time of vapor deposition and deposition, ion beams with a certain amount of energy are used for bombardment and mixing, so as to form a simple or compound film layer.The method can grow films of any thickness continuously at low bombardment energy and synthesize compound films with ideal chemical ratio at or near room temperature.At present, there are few researches on the application of this technology in antibacterial materials, and it has great potential for development in the future.Plasma immersion ion implantation deposition is to generate plasma in a vacuum chamber in advance, and then apply negative bias pressure on the work piece to obtain ion implantation or deposition, which has both ion implantation effect and conventional ion plating effect.This method can improve the physical and chemical properties of the films and composite layers, which can be applied in the research of antibacterial materials.

Vacuum silver-plated antibacterial finish

Conventional electroless silver finishing process is simple, but the durability, fastness and evenness are not ideal.Vacuum silver plating finishing under high vacuum conditions, on the one hand, reduces the collision between silver atoms and gas molecules, thus reducing the occurrence of chemical reactions, on the other hand, it can keep the surface of the plated textiles clean, and improve the adhesion fastness of silver atoms and fibers.

In vacuum silver plating, the textile must not contain moisture, otherwise the vacuum will be reduced.The adhesion fastness is the key of product quality.

Silver plated antibacterial finish

Sputtering of textiles can be carried out in dc two-stage sputtering device. In sputtering, the adhesion fastness of metal on textiles is better than that of vacuum plating.In addition, the standard moisture recovery, heat resistance and hydrophilic group content of the fiber will affect the splash effect.Compared with cotton and viscose fabric, polyester fabric is easier to splash, and the air permeability of the sputtered polyester fabric is basically unchanged, which is related to the metal film wrapped on the surface of each fiber, rather than adhering to the gap of the fiber.Compared with untreated textiles, the stiffness and flexibility of spattered textiles vary from 4% to 24%, that is, slightly stiffening tendency, which is similar to that of general resin finishing and thermal setting treatment.

The new silver-plated fibers and fabrics developed by magnetron sputtering and composite coating technology have excellent antibacterial properties and are the top materials used for severe medical dressers such as burns.At the same time, the silver content can be increased and the fabric can be isolated from electromagnetic radiation.

Renewable antibacterial finishing

Usually the antibacterial properties of textiles are easily obtained in finishing, but are also easily lost in washing.In order to improve the durability of antibacterial finishing of textile materials, regenerability of antibacterial function is a new finishing method.In this new process, the parent compound (potential antibacterial agent) replaces the antibacterial agent itself and is used in the antibacterial treatment of cellulose materials.Before the antibacterial group is activated, the potential antibacterial agent covalently binds to the cellulose material, which can then be activated by a reversible chemical process (such as REDOX reaction), releasing the antibacterial group.This finishing method is similar to the wrinkle-resistant finishing process, and the activation reaction can be achieved in conventional processes such as bleaching.

The potential antimicrobial agent is a derivative of hydanilide, namely, mono-hydroxymethyl-5, 5-dimethyl hydanilide (MDMH).Using MDMH to treat cellulose fabric, the hydroxymethyl in MDMH can react with the hydroxyl group on the molecular chain of cellulose fiber to produce covalent bond.The secondary amino group in MDMH can be treated with the solution containing effective chlorine to generate haloamine structure. The chlorine polarity of the covalent bond in the haloamine structure is very strong and has oxidation effect, which can lead to the inactivation of microorganisms, thus achieving the antibacterial effect.After chlorination, the chlorine atom is reduced to chloride, and the halogen-amine bond is converted to secondary amino group, which can be regenerated after being chlorinated again, so as to realize the regeneration of antibacterial function.

Nanometer antibacterial material and its application

Nano-antibacterial materials can be divided into natural nano-antibacterial materials, organic nano-antibacterial materials and inorganic nano-antibacterial materials.Nanometer silver ion antibacterial agent plays a leading role in inorganic antibacterial agent, which can be uniformly dispersed in products and has no special requirements on processing technology, and can be widely used in all kinds of fiber products.It relies on contact reaction to destroy microbial activity, and its antibacterial component is silver ion, with long-lasting antibacterial effect.

By means of physical adsorption and ion exchange, the silver ion is fixed on the surface of porous materials such as zeolite, ceramic, silica gel and so on to make antibacterial agent, and then nanometer, and then it is added to the corresponding products by means of coating printing, melt spinning and other methods to obtain the material with antibacterial ability.With silver composite as the main antibacterial body and nano TiO2 and SiO2 as the carriers, the special effect of nano powder particles greatly improves the overall antibacterial effect, giving full play to the temperature resistance, powder fineness, dispersion and functional effects.

(source: textile herald)