05/08/2022
First, we investigated what an infection control filter is.
As a filter for a non-woven mask with a 3-layer or 4-layer structure that is generally available on the market.
The material used seems to be a non-woven fabric made by a method called melt blown.
http://www.ss-sangyo.co.jp/サージカルマスクの不織布について/
The fiber diameter of a general spun bond is 1.5 to 4.0 denier (1 denier = 1 g at 9000 m).
The fiber diameter of melt blown is 0.1 to 0.3 denier, and it is composed of ultra-fine fibers.
It seems that it is used as various filters due to its precise structure. .
The Vietnamese-made 4-layer mask that Mr. Horiuchi mentioned is also made by the melt blown manufacturing method.
Non-woven fabric was used as a filter.
https://item.rakuten.co.jp/lafeed2017/mask4/
Based on the above,
The reason why the non-woven fabric made by the melt blown method is not used for the mascope
The following is a summary of the advice given by Dr. Shinbo.
① The greater the pressure loss of exhaled breath due to the mask, the harder it is to breathe.
Fine-grained non-woven fabric is not suitable as a material for endoscopy masks.
② The subject is a virus from the outside floating in the air.
Rather than avoiding inhalation, the virus that comes out of the subject's mouth It is a mask to prevent it from scattering.
In this case, the virus does not come out alone, but is contained in the droplets.
You can prevent the spread of the virus by trapping the droplets firmly.
Instead of sandwiching a non-woven fabric made by the melt blown method in the mascope,
The water absorption sheet on the inside traps the liquid firmly.
③ The virus is about 0.1 to 0.5 ㎛, which is much smaller than the mesh of the mask.
It is because of the intermolecular force that it can be trapped with a mask.
* Intermolecular force is the action of a virus that has invaded a filter by hitting somewhere on a thick filter and being collected.
https://www.nhk.or.jp/kenko/atc_1167.html
The size of the droplets is about 3.0 to 5.0 ㎛, which is larger than the virus alone.
It is used in Mascope without using non-woven fabric made by the melt blown method.
It is considered that the spun-bonded non-woven fabric (1.5 to 4.0 denier) can be sufficiently trapped.
Material: 100% polyester, basis weight: 50g /, thickness: 0.3-0.4mm
http://fushokufu.co.jp/service/spun.html
④ If the air resistance of the mask increases, the gap between the endoscope insertion hole and the mask and the skin. Expiratory breathing may increase.
⑤ Even if the mask has an aerosol leak between the fibers of the mask
It is useful for preventing the spread of droplets and has the effect of reducing the amount of exposure to people facing each other. It turns out to be expensive.
Last but not least, I have attached the composition of Mascope.
【composition】
・ Two-layer non-woven fabric: Spun-bonded non-woven fabric: 100% polyester, basis weight: 50 g /
・ Water absorption material: 55% polyester, 45% rayon, basis weight: 50g /
The thickness is not official, but both materials are 0.2-0.4mm.
Certification: ISO 13485 (medical device, external medical d
