Significance of Antibacterial Polyester Fibers
In daily life, pathogenic bacteria will inevitably be contaminated due to the humidity and temperature of the environment, various sweat stains, oils, etc. But the ordinary fabrics do not have a bactericidal function. In this way, pathogenic bacteria such as mites, Escherichia coli, Candida albicans, and Staphylococcus aureus can easily survive and reproduce. If applied for personal use, it is not conducive to personal hygiene; and if applied for textiles in public places, it is easy to make the breeding of pathogenic bacteria and cross-infection, causing harm to human health.
Therefore, the development of antibacterial fibers has become more and more important.
Classification of Antibacterial Agents
1. Natural Antibacterial Agent
Natural antibacterial agents refer to high-molecular organic substances with antibacterial functions directly extracted from certain animals and plants.
Animal-derived antibacterial agents mainly include chitin, chitosan, and insect antibacterial proteins. Plant-derived antimicrobials mainly include acetylcholine extracted from mugwort, glycyrrhizin extracted from licorice, aloin extracted from aloe, and so on.
Natural antibacterial agents have the advantages of safety, non-toxicity, environmental protection, and good biocompatibility, but they have disadvantages such as poor heat resistance and washability, and low raw material yield.
2. Organic Antibacterial Agent
Most organic antibacterial agents are small organic molecules, with organic acids, phenols, and alcohols as the main components. The common ones include halogenated
substances, isothiazoles, pyridine metal salts, aldehyde compounds, quaternary ammonium salts, etc.
Compared with inorganic antibacterial agents, the advantages of organic antibacterial agents are high-efficiency sterilization and various types. But the disadvantages are toxicity, easy precipitation, poor heat resistance, etc., so the application has been greatly restricted.
3. Inorganic Antibacterial Agent
According to different mechanisms, inorganic antibacterial agents can be divided into: metal ion-loaded antibacterial agents, photocatalytic antibacterial agents, and composite antibacterial agents.
Metal ion-supported antibacterial agents are obtained by combining active ingredients with carriers through adsorption, coating, etc.
Photocatalytic antibacterial agents are represented by titanium oxide and zinc oxide.
Composite antibacterial agents include inorganic and organic antibacterial agents and composites of different inorganic antibacterial agents.
Inorganic antibacterial agents have the advantages of high thermal/chemical stability, broad-spectrum antibacterial, good washability, and long-lasting antibacterial effects. However, some agents are easy to produce Hazardous and are not allowed to be used in textiles.
Antibacterial Modification of Fibers
1. A reactive or compatible antibacterial agent is added before the polyester polycondensation reaction. The antibacterial polyester chip is prepared by in-situ polymerization modification. The Hubei Decon technical department is developing such polyester chips now. And then the antibacterial polyester fiber is produced by melt spinning.
The in-situ polymerization method means the antibacterial agent is uniformly dispersed in the polymerization system during the process.
The advantage of this method is that adding the antibacterial agent in the polymerization stage can make the antibacterial agent fully mixed with the matrix and improve the dispersion uniformity in the polymer. The disadvantage is that it may affect the physical properties, and ultimately affect its spinnability and usage characteristics.
2. Extrude, blend, and granulate the added antibacterial agent and non-antibacterial polyester chips, and then prepare antibacterial polyester fibers by melt spinning.
The blending antibacterial modification method refers to adding a certain amount of antibacterial agent to the polymer melt before spinning and then spinning through conventional spinning equipment to obtain fibers with antibacterial function.
The advantage of the blending modification method is that it has good flexibility in adding antibacterial agents, but the disadvantage is that it requires high thermal stability, dispersibility, and compatibility with polyester.
3. Composite spinning of antibacterial polyester masterbatch and regular polyester chips
The composite spinning method means that polyester chips with antibacterial components and common polyester chips are passed through twin screws, and the melt is made into antibacterial fibers with skin-core type, mosaic type, hollow multi-core type, side-by-side type, and other structures through composite spinning components.
Compared with blend spinning, the composite spinning method can get the same effect but with less amount of antibacterial agent. But it has the disadvantages of difficult spinneret processing and high production cost.
4. Polyester fabrics are coated with an antibacterial finishing agent.
Post-treatment modification refers to the use of solutions containing antibacterial agents to impregnate, pad, or coat fibers or fabrics in the process of fabric printing, dyeing, and finishing so that antibacterial agents can act on the surface of fibers or fabrics through adsorption, thermal curing or chemical reactions, thus giving it an antibacterial effect.
The advantage of such a method is that the operation technology is simple, and the antibacterial agent can be directly finished on fibers, yarns, fabrics, garments, or various textile products. However, because the antibacterial agent only exists on the surface of the fabric, the antibacterial effect is greatly reduced after repeated washing of the fabric. And there is also an environmental pollution problem in the post-treatment process.
5. Graft copolymerization of reactive antibacterial agents on fibers or fabrics
The method refers to components with reactive groups on the surface of fibers or fabric through chemical bonding to endow them with antibacterial functions.
The advantages are stable performance and long service life. However, such modification usually requires the pretreatment of fibers or fabrics, so the reaction process is complicated and the reaction conditions are strict.