Requirements for the processing and use of antibacterial agents for plastics
antibacterial agents for plastics not only need to have high-efficiency, broad-spectrum antibacterial properties, good antibacterial sustainability, and keep antibacterial plastics antibacterial for a long time; Non toxic and odorless, no pollution to products and the environment; It has good compatibility with plastics and has no adverse effect on the performance of plastic products; Good color stability, no discoloration during storage and use; Good chemical stability, acid, alkali and chemicals resistance; There is a relatively low price, which will not significantly increase the cost of materials after use; It is also necessary to fully consider the impact of antimicrobial agents under harsh conditions such as high temperature, high heat and strong shear during plastic processing, and require that antimicrobial agents have high thermal stability and do not decompose and deteriorate during plastic extrusion and processing. At present, antibacterial agents include inorganic antibacterial agents, organic antibacterial agents, natural antibacterial agents and polymer antibacterial agents. Despite the large number of antibacterial agents (taking Japan as an example, there are 500 kinds of technical drugs and about 700 kinds of preparations of antibacterial and anti mildew agents, mainly organic antibacterial agents, but only a few antibacterial agents can meet the processing and use requirements of antibacterial plastics and their products.
inorganic antibacterial agents are the new antibacterial agents with the most extensive application and the greatest market potential in antibacterial plastics. They are a kind of antibacterial agents made by using the bactericidal and antibacterial properties of metals such as silver, copper, zinc, titanium and their ions. Human It has long been found that silver, copper, zinc metals and their compounds have bactericidal function. As early as 4000 years ago, India used copper pots to store water for disinfection, and ancient Greek soldiers in the 5th century BC used silver vessels to hold water for drinking directly. In clinical medicine, the executive secretary of aapimc, vy Chen, and the chairman of apimc, the president of ialta, Jean Claude Steinmetz, and the vice president of the Engineering Research Institute of Chang'an Automobile Co., Ltd./the executive chairman of ialta/Mr. Cao Du reported to make the future development plan and work plan of the association. Gno solution or colloidal silver was used to treat wounds, and silver thiamine was also used to fight fungi and inhibit viruses. However, it was the Swiss botanist lacklin who first clearly proposed that Ag ions could kill algae in 1893. He found that Ag ions with a concentration of 10-8mol/l could kill algae. Subsequently, it was found that copper, zinc and other metal ions also have antibacterial properties. Among all metal ions, silver ions have the strongest antibacterial properties, so silver ions and their compounds are often used. In the early 1980s, Japanese scientists began to add silver compounds directly to the resin and made antibacterial plastics with inorganic antibacterial agents. However, the antibacterial plastic prepared by directly adding silver salt has significantly decreased performance, blackened color, easy precipitation of as' when contacting water, short antibacterial validity and low application value. Later, materials with porous structure that can firmly support metal ions, or materials that can form stable chelates with metal ions, such as activated carbon, were used to carry metal ions. At present, inorganic antibacterial agents are mostly made of zeolite, wollastonite, chlorite, clay, ceramics, insoluble phosphate, soluble glass and other substances as carriers, loaded with silver and other metal ions, which have little recycling value. They are broad-spectrum antibacterial, high heat-resistant temperature, long-lasting, safe, and have obvious advantages in the application of antibacterial materials. They are the most promising antibacterial agents for plastics, chemical fibers, and ceramics
compared with inorganic antibacterial agents, although organic antibacterial agents were developed early in industrial application, their application in antibacterial materials such as plastics is greatly limited. However, organic antibacterial agents have their own application characteristics in some plastics. For example, the effective antibacterial speed of organic antibacterial agents is faster than that of inorganic antibacterial agents, and the anti mildew effect is better. The process operability added to plastics is better than that of inorganic antibacterial agents, and the color stability during storage and use is also stronger than that of inorganic antibacterial agents. Therefore, organic antibacterial and anti mildew agents play a certain role in the development of key monomers, special additives, complete engineering technology for the preparation of environmental friendly high-performance resins, and the application of environmental friendly high-performance surface materials and plastic solutions
natural antibacterial agent is the earliest antibacterial agent used by human beings. The gum used in the mummy wrapping cloth in the Egyptian pyramids is a natural antibacterial agent. At present, the most commonly used natural antibacterial agent is chitosan (chitin). Chitosan is produced by deacetylation of chitin. Chitin exists in the shell of insects and the cell wall of fungi. In nature, the synthesis of chitin reaches billions of tons every year. It is the second largest natural polymer material in nature. Chitin is obtained by removing inorganic calcium from the insect shell by pickling and protein by dilute alkali boiling. Chitin is deacetylated in concentrated alkali to obtain chitosan. The poor thermal stability and large amount of natural antibacterial agents are the main reasons that limit their extensive application in plastics
polymeric antibacterial agents, also known as antibacterial polymers, are antibacterial polymers themselves, such as copolymerizing antibacterial group monomers in the polymer chain, or grafting antibacterial groups on the polymer chain. Their development and application are still in the initial stage