Properties

How is copper currently used as an antimicrobial agent?
Copper is already an active ingredient in many different types of antimicrobial products such as in agriculture, in marine environments, in healthcare environments and in houses. Copper is an active ingredient in anti-plaque mouthwashes, toothpastes and various other medicines. Copper sink strainers and scourers for pots and pans can hepl prevent cross-contamination in the kitchen.

Why copper-containing surfaces are more advantageous than other antimicrobial surfaces?
Products made of copper and copper alloys maintain their antimicrobial properties for a very long time. Even in case these surfaces get scratched, their antimicrobial efficacy is maintained intact- they do not worn out like coatings or machined surfaces of other types. Copper alloys are the only solid surfaces that have been registered as products with positive properties for public health the U.S. Environmental Protection Agency (EPA).

How can copper help prevent the spread of infections?
Pathogens can remain alive and infectious on surfaces for hours, days, even months, providing a reservoir of infections which can be transferred by touch. However, pathogens cannot survive on copper surfaces. As a result, copper can break the chain of infection transfer and act as a supplement to regular cleaning in order to improve hygiene.

Where else can antimicrobial copper be used?
Antimicrobial copper can be used for frequently touched surfaces in hospitals, schools, gyms, public buildings and public transport.

Is it pure copper that has an antimicrobial effect?
No, copper alloys do too. Tests have been carried out on pure copper, high coppers, brasses, bronzes, copper-nickels and copper-nickel-zincs. The latter are sometimes referred to as “nickel-silvers” because of their shinny white colour, even though they contain no silver. The U.S. Environmental Protection Agency (EPA) has registered an official table of antimicrobial copper alloys with a nominal copper contant higher than 60%. The higher the copper contant of an alloy is, the faster microbes are eliminated. When selecting a copper alloy for a certain product, it is important that the requirements for mechanical properties, the manufacturing process and , of course, the desired colour of the product also be taken into consideration. Copper alloys offer a great variety of attractive colours, from brass yellow to bronze dark brown.

By what means does copper eliminates pathogens?
Copper is an essential nutrient for humans, as well as for bacteria, but in high doses, copper ions can cause a series of negative events in bacterial cells. The exact mechanism by which copper eliminates bacteria is still unknown, however several theories exist and are being studied. They include:

• Causes leakage of potassium or glutamic acid through the outer membrance of bacteria
• Disturbs osmotic balance
• Binds to proteins that do not require copper
• Causes oxidative stress by generating hydrogen peroxide

Do copper and copper alloy surfaces change colours in the course of time?
Yes. Their colour change due to natural oxidation and becomes darker. The amount of time required for a colour change to take place depends on the alloy and the environmental conditions. Under conditions of exposure inside buildings, quite a number of years are required for major changes to become visible.

Does the natural oxidation of copper and its alloys affect their antimicrobial properties?
No. On the contrary, it has been proved that the more copper, brass and their surfaces are oxidized and become darker, the more efficient in eliminating microbes they become.