1. Necessity of antibacterial finishing
Antibacterial finishing of textile materials is very necessary, it can achieve the following goals:
Avoid cross infection of pathogens;
Control bacterial infections;
Inhibit bacterial metabolism, thereby preventing odor generation;
Protect textiles from stains, discoloration and deterioration.
2. Requirements for antibacterial finishing
Textile materials, especially clothing, are prone to wear. It is important to consider the effects of stress-strain and thermal and mechanical effects on antibacterial finishing substrates. In order to achieve the best finishing effect, antibacterial finishing of textiles must meet the following requirements:
Resistant to washing, dry cleaning and hot pressing;
Selective activity against harmful microorganisms;
Do not cause harmful effects to manufacturers, users and the environment;
Comply with the laws and regulations of the management agency;
Compatible with chemical processes;
The application method is simple;
Will not reduce the quality of the fabric;
Resistant to body fluids, resistant to disinfection / sterilization.
3. Antibacterial finishing method
Antibacterial agents can be applied to textile base fabrics through exhaust dyeing, pad baking, coating, spraying and foaming techniques, or antibacterial agents can be directly added to the fiber spinning dope. It is reported that commercial antibacterial agents can already be added online during dyeing and finishing operations. Methods to improve finishing durability include:
Reduce the solubility of the fiber inside and surface-active substances;
Treatment of fibers with resin, cured product or cross-linking agent;
Add antibacterial microcapsules to the fiber matrix;
Coated fiber surface;
Chemical modification of fibers by forming covalent bonds;
Graft polymers, homopolymers and / or copolymers with fibers.
4. Antibacterial mechanism
The negative effect of radon on bacterial activity is generally called bacteriostatic. Microbial activity is distinguished by the term bactericidal and static, sterilizing means destroying microorganisms, and static means inhibiting the growth of microorganisms without too much damage.
Substances that affect the activity of bacteria are called antibacterial agents. Bacteria here mainly refer to fungi. Antibacterial substances have different modes of action. In traditional immersion finishing, antibacterial substances diffuse and destroy bacteria, killing them. This finishing method has poor durability and may cause health problems. The non-impregnation method or the method using the biological inhibitory oil has good durability and does not cause any health problems. Antibacterial finishing of most textiles is achieved by diffusion.
The diffusion rate directly affects the effectiveness of finishing. For example, during ion exchange, the release rate of the active substance is slower than that of direct diffusion, so the effect is weak. Similarly, when the active substance is not released from the fiber surface, its antibacterial finishing effect is also poor. Only when the active substance comes into contact with the bacteria does it become active. New antibacterial technologies were developed based on research in medical, toxicological, and ecological principles.
According to the effect of antibacterial textiles on the activity of microorganisms, they can be divided into passive and active types. Passive antibacterial textile materials do not contain any active substances, but their surface structure (lotus effect) can negatively affect the growth of microorganisms (anti-adhesion effect). Active antibacterial textile materials containing antibacterial substances act on the outside or inside of microbial cells.
5. Advantages of antibacterial textiles
Currently, there are many types of textiles that consumers can benefit from. Initially, the main purpose of antibacterial finishing was to protect textiles from bacteria, especially fungi. Therefore, antibacterial agents are used for antibacterial finishing of uniforms, tents, protective textiles and technical textiles (such as geotextiles). Since then, antibacterial finishing has also been applied to home textiles such as curtains and bathroom mats. At present, the application of textile antibacterial finishing has been extended to the outdoor field, medical care field and sports and leisure products field.
The new technology of antibacterial finishing has been successfully applied in the field of nonwovens, especially in medical textiles. Textile fibers with antibacterial properties can be used alone or blended with other fibers to achieve antibacterial effects. Bioactive fiber is an improved form of finishing, and its structure contains chemical drugs, such as synthetic drugs with bactericidal properties. These fibers can be used not only in the medical and health prevention fields, but also in the production of daily textiles and technical textiles.
Applications of bioactive fibers include sanitary materials, dressing materials, surgical materials, gas and liquid filter materials, air conditioning and ventilation, building materials, special materials for the food industry, and applications in the fields of medicine, footwear, clothing, and automobiles.
6. Evaluation of antibacterial activity
A variety of test methods have been used to test antibacterial activity. Some of the commonly used test methods are as follows:
Agar diffusion test;
Challenging test (quantitative);
Burial test
Humid box test;
Contamination test.
The agar diffusion test is a preliminary test for the detection of diffusion antibacterial finishing. It is only applicable to textiles and not for non-diffusive finishing. Through challenging tests, the actual bacterial count difference between the finished and untreated materials can provide an objective assessment of antibacterial activity.
A series of antibacterial activity test methods can be obtained from AATCC (American Standard), DIN (German Standard), JIS (Japanese Standard) and SN (Swiss Standard). The degree of antibacterial activity of active substances can be expressed through special antibacterial activity and general antibacterial activity. In Japanese standards, the general antibacterial activity or antibacterial effect is evaluated based on the difference between the initial bacterial count (Ma value) of the unmodified material and the bacterial count (Mc value) of the modified material after 18 h of culture; special antibacterial activity Or the bacteriostatic effect was evaluated based on the difference between the reference value (Mb value) and the number of bacteria (Mc value) after the sample was cultured for 18 h. Due to the limitations of the existing methods, a new test method-IS / TC / 38 / WG23 antibacterial finishing textile product test method has been developed through comprehensive consideration of finishing technology, skin diseases and ecological aspects of finishing. .
Evaluation of 7 on mold and fungi
The effects of on molds and fungi can be evaluated using the following three practical test methods:
In the growth test of 5 different mixtures of mold and fungus, evaluate the extent to which fungi can grow on textiles. This method can be evaluated not only by direct observation, but also by measuring the specific elongation ratio of the material;
The inhibitory zone test can detect the protective effect of finishing agents on textiles to prevent textiles from growing mildew spots and molds. The evaluation method is to rate the growth of fungi on the test material and observe the spread of the antibacterial agent in the inhibition zone around the test sample;
The third test is the humidity box test, which can express the problem of mold staining on textiles in a humid environment. The evaluation method is to directly observe the degree of mold growth, or to evaluate it by a tensile strength test. 1 Necessity of antibacterial finishing
Antibacterial finishing of textile materials is very necessary, it can achieve the following goals:
Avoid cross infection of pathogens;
Control bacterial infections;
Inhibit bacterial metabolism, thereby preventing odor generation;
Protect textiles from stains, discoloration and deterioration.
