Inorganic antimicrobial agent is a new type of antimicrobial agent with wide application and market potential in antimicrobial plastics. It is the use of silver, copper, zinc, titanium, and other metals and their ions of bactericidal and antibacterial properties and a class of antimicrobial agents. Among all the metal ions, silver ions have strong antibacterial properties, so it is mainly silver ions and their compounds that are often used.
However, the antibacterial plastic prepared by directly adding silver salts has significantly reduced performance, like darkened, easily precipitated when in contact with water, short antibacterial validity, and low application value. The use of a porous structure can be firmly loaded with metal ions of the material, or can form a stable chelate with metal ions of the material carrying metal ions, such as activated carbon can improve these problems.
At present, inorganic antimicrobial agents mostly use zeolite, wollastonite, chlorite, clay, ceramics, insoluble phosphate, soluble glass and other substances as carriers loaded with silver ions, zinc ions, or copper ions. The agents have antimicrobial broad-spectrum, high heat-resistant temperature, long-lasting, safe, antibacterial materials in the application of obvious advantages, which is a promising application for plastics.
Langyi’s silver ion, zinc ion, and copper ion antimicrobial additives
What performances should an antimicrobial agent in plastics have?
(1) has a high efficiency, broad-spectrum antibacterial performance, antibacterial continuity is good, keep antibacterial plastic can be long-term antibacterial.
(2) non-toxic and odorless, no pollution to products and the environment.
(3) Good compatibility with plastics, no adverse effects on the performance of plastic products.
(4) Good color stability, no discoloration in the process of preservation and use.
(5) Good chemical stability, resistant to acids, alkalis and chemicals.
(6) low price, the use of the material will not significantly increase the cost.
(7) has high thermal stability, does not decompose and does not deteriorate in the process of plastic extrusion and processing.
Evaluation of the antimicrobial effect of antimicrobial agents
The commonly used indicators in the evaluation of antimicrobial effect are antimicrobial rate and inhibition circle. The antimicrobial rate can be calculated by the following formula: antimicrobial rate = (the number of bacteria on the blank sample – antimicrobial sample bacteria) / the number of bacteria on the blank sample × 100%
The inhibition circle method is another way to measure the antibacterial effect of antimicrobial agents, mainly used to determine the antibacterial effect of antimicrobial agents. It is a qualitative or semi-quantitative method. Its method is to place the bacterial culture on a nutrient agar plate, and then place the prepared antibacterial plastic on the colonies of the plate, and leave it in the mold incubator at 36 ℃ for 18-24 hours. The bacterial growth around the cultivated antibacterial plastic discs will be inhibited so as to form a transparent circle, that is, the inhibition circle. The size of the inhibition circle represents the strength of the antibacterial ability of the tested plastic.
