Antibacterial agents represent a history of human beings' confrontation with viruses.

The development history of antibacterial agents is not only a history of human beings' continuous confrontation with viruses and bacteria but also an evolutionary history.

Technological Progress of Antibacterial Plastics at Home and Abroad

Nanoplastics refer to organic/inorganic nanocomposites formed by dispersing inorganic fillers in organic polymers at the nanoscale. Such plastics possess excellent properties that are not found in general engineering plastics, making them a high-tech new material with broad prospects for development and application. In terms of the technology and application of antibacterial plastics, the developed countries mainly include the United States, Japan, Germany, etc., and the developing countries are mainly represented by China.

Antibacterial plastics are usually composed of antibacterial agents (at the nanoscale and microscale) and base resin materials. However, when antibacterial agents are applied, problems such as color change, poor heat resistance, and uneven dispersion often occur, preventing their normal application. The use of antibacterial masterbatch technology can solve the above problems. Especially in the production of plastic products, chemical fibers, and other products, as long as the antibacterial masterbatch is simply blended, it can be processed and formed. The products have permanent broad-spectrum antibacterial properties, with an antibacterial rate reaching 99%. Antibacterial plastic products have the function of inhibiting the reproduction of bacteria on plastic products. Specifically designed antibacterial plastics can kill the bacteria on the products. The synthesis technology of composite antibacterial agents (synthesizing new ones containing silver and zinc) is adopted to control the discoloration of silver antibacterial agents. The composite formula of inorganic antibacterial agents and organic antibacterial agents is used to improve heat resistance, and the dispersant formula is adopted to enhance the dispersion of antibacterial agents and strengthen the antibacterial effect. In addition, in response to the specific conditions of various usage requirements for antibacterial products, a series of long-acting control technologies have been developed, enabling antibacterial materials to truly demonstrate their permanent antibacterial properties.

Due to the selection of safe and broad-spectrum antibacterial agents, this kind of antibacterial plastic has good antibacterial properties and a wide range of antibacterial types (including bacteria, fungi, viruses, etc.). Long-term use will not lead to the mutation of microorganisms or the development of tolerance. It can prevent nosocomial infections and has an inhibitory and killing effect on serious pathogenic bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli O-157.

The so-called antibacterial refers to the ability to inhibit the growth and reproduction of microorganisms within a certain period of time. Antibacterial is different from disinfection. It does not require the immediate killing of harmful microorganisms but focuses on inhibiting the growth and reproduction of microorganisms during long-term use.

Inorganic antibacterial agents mainly have two antibacterial mechanisms according to different types of antibacterial agents. One is the antibacterial mechanism of the metal ion dissolution type. During the use of the antibacterial agent, the gradually dissolved metal ions react with functional groups containing sulfur and nitrogen, such as sulfhydryl (-SH) and amino (-NH2), present in the proteins and nucleic acids of microorganisms, destroying the activity of enzymes in the cell membrane or cell protoplasm, thus having antibacterial ability. The other principle is the oxidation type antibacterial mechanism. That is, the antibacterial agent decomposes free electrons (e) and holes (h+) by itself in water or air. The holes activate the oxygen in the air to generate reactive oxygen species and HO., which undergo oxidation reactions with various organic substances in microorganisms, destroying the bacterial structure and achieving the antibacterial effect.

Inorganic Antibacterial Agents

Utilizing the antibacterial capabilities of metals such as silver, copper, and zinc, through methods such as physical adsorption and ion exchange, metals such as silver, copper, and zinc (or their ions) are fixed on the surface of porous materials like fluorite and silica gel to make antibacterial agents. Then, adding these antibacterial agents to the corresponding products can obtain materials with antibacterial capabilities. Metals such as mercury, cadmium, and lead also have antibacterial capabilities, but they are harmful to the human body. Ions such as copper, nickel, and cobalt have colors, which will affect the aesthetics of the products. Zinc has certain antibacterial properties, but its antibacterial strength is only 1/1000 of that of silver ions. Therefore, silver ion antibacterial agents play a dominant role among inorganic antibacterial agents. Silver ion antibacterial agents are the most commonly used antibacterial agents, which are in the form of white fine powder and can withstand a heat temperature of over 1300°C. The carriers of silver ion antibacterial agents include zirconium phosphate, zeolite, ceramics, activated carbon, etc. Sometimes, to improve the synergistic effect, some copper ions and zinc ions are added. In addition, there are also inorganic antibacterial agents such as zinc oxide, copper oxide, ammonium dihydrogen phosphate, and lithium carbonate.