The role of dust masks
, as the name suggests, is to prevent the inhalation of dust. The key to its role is the performance of the filter material, mainly:
1. The fiber fineness of the filter material
It is expressed in terms of fiber diameter and the unit is micrometers. Generally, the fiber diameter of the filter material used for dust masks is preferably less than 5 microns. The diameter of the commonly used polypropylene ultrafine fiber is 4.0 microns, and the fiber diameter of the perchloroethylene ultrafine fiber filter material is less than 2 microns.
2. The composition and structure of the filter material
The organizational structure of the filter material is related to the manufacturing process of the filter material. At present, the molding process of synthetic fiber non-woven filter material mainly includes acupuncture method, direct injection method, bonding method, hot melt method, etc. The hot melt injection molding method is mostly used, and with this method, two or more different fiber materials can be used for composite molding, which improves the efficiency of dust resistance, is relatively soft and has good air permeability.
3. The chargeability of the filter material
The size of the filter belt classic two is positively correlated with the composition efficiency, that is, the greater the amount of static charge, the higher the dust resistance efficiency.
When dust passes through the filter material, the following happens:
(1) Collision retention: When the particle size of the dust is larger than the gap between the filter media fibers, the dust collides on the surface of the filter media, changes direction due to the reaction of inertia and force, and settles and adheres to the surface of the filter media.
(2) Hooking effect: There are burrs on the fiber. When the dust passes through the filter material, it is hooked by the burrs on the fiber to prevent the particles from penetrating.
(3) Multi-layer filtration: the filter material is made of superfine fibers lapped and woven into a net, and it has a multi-layered "three-dimensional structure". When the dust passes through the filter material, it is intercepted layer by layer.
(4) Electrostatic effect: The filter material has an electrostatic charge, which repels the quite polar dust particles, and has an adsorption effect on the dust particles of the opposite nature, that is, captures the dust.