"Antibacterial" means

This time, I'd like to write about the function and standards of "antibacterial" products.

The term "antibacterial" has become particularly common recently, but it's highly likely that it's ineffective against viruses, including the novel coronavirus.

As you may have learned in school, "bacteria" and "viruses" are completely different things.

Neither can be easily seen, so it's hard to tell, but their sizes are quite different.

Bacteria are approximately 1 µm (micrometer), or 0.001 mm (millimeter).

Viruses are approximately 1 nm (nanometer), where 1 nm is 0.001 µm.

In other words, viruses are 1/1000th the size of bacteria.

Furthermore, not only are they different in size, but their structures are also different.

Bacteria are single-celled organisms, so they can reproduce on their own.

Viruses do not have cells. They enter cells and reproduce through the power of those cells.

Because their reproduction patterns are fundamentally different, the countermeasures against bacteria and viruses are also different.

I've digressed a bit, but products that are effective against viruses are generally advertised as "antiviral," so it might be a good idea to pay attention to this when choosing products.

Now, regarding antibacterial effects, what criteria are used to determine whether or not they are effective?

Basically, textile products are confirmed using a test method called the bacterial solution absorption method, as defined in JIS L 1902 (ISO 20743).

Detailed instructions can be found at the link below.

Simply put, this test involves applying a bacterial solution to a fabric and measuring the increase in bacteria after 18 hours.

A similar test is performed on unprocessed cotton fabric. Subtracting the increase in bacteria on the test fabric from the increase in bacteria on the cotton fabric yields the antibacterial activity value.

An antibacterial activity value of 2.0 or higher indicates effectiveness, and 3.0 or higher indicates strong effectiveness.

Furthermore, this antibacterial activity value is also used when obtaining product certification marks, commonly known as the SEK mark.

For antibacterial and deodorizing marks, an antibacterial activity value of 2.2 or higher is required.

So, how is antibacterial effect imparted to textile products?

There are two main types:

Post-processing antibacterial and material antibacterial.

Post-processing antibacterial involves applying an antibacterial agent to the fabric after it has been made. While compatibility with the material is a factor, it can impart antibacterial effects to various fabrics. However, the functionality may decrease with washing in many cases.

Antibacterial materials are those that have antibacterial properties because they are incorporated into the fibers themselves. The effect is minimally diminished by washing and often lasts semi-permanently. However, because this type of yarn must be used, the types of yarn that can be used in the fabric are somewhat limited.

Our company's "antibacterial" products are basically antibacterial yarns, and therefore refer to antibacterial materials.

For example, the regenerated collagen fiber we have already introduced also has antibacterial properties and can be called an antibacterial yarn. You can find more information about regenerated collagen fiber here ↓

In addition to the above, we have recently started handling antibacterial polyester yarn.

Since antibacterial effects are observed at approximately 10% concentration, we are also considering selling it as a blended yarn.