Non-woven electret masterbatch, do you choose right?

Melt-blown polypropylene non-woven fabric is the core filter material for masks. Why does melt-blown polypropylene non-woven fabric have strong filtering capabilities? This starts from the structure and performance of the filter material and the filtering mechanism. The filtering mechanism of the melt-blown filter material is mainly divided into two types: mechanical barrier and electrostatic adsorption:

1. Mechanical barrier can be divided into the following situations:

(1) Droplets larger than 5um in the air can be blocked by the filter material.

(2) When the diameter of the fine dust is less than 3um, the fine dust is mechanically intercepted by the fiber layer of the curved channel in the mask filter material.

(3) When the particle size and air velocity are both large, the particles are captured due to inertial collisions with the fibers. When the particles have a low flow rate and the particles are low, the particles are captured due to Brownian motion impacting the fibers.

2. Electrostatic adsorption

Electrostatic adsorption refers to the capture of dust bacteria and viruses through the coulomb force of charged fibers when the fibers of the filter material are charged.

The fibers of the polypropylene ultrafine fiber melt-blown material form a multi-layered criss-cross network structure, and are randomly distributed in three dimensions, so that the fiber web contains a large number of tiny voids. Curved channel structure, this type of structure can greatly increase the probability of particles and fibers in the air colliding and staying during filtration, and is very suitable for use as a filter material.

What is non-woven electret masterbatch? Before introducing electret polypropylene meltblown nonwoven fabric and nonwoven electret masterbatch, first introduce the concept of electret:

      Electrets: Dielectrics are polarized in the electric field. Many dielectrics exist simultaneously with the external electric field and disappear at the same time, and there are also some dielectrics. The polarization phenomenon is not removed by the external electric field after being affected by the external electric field. And completely disappear, there is a phenomenon that the polarized charge exists "permanently" on the surface and inside the dielectric. This kind of dielectric that is polarized and can "permanently" maintain the polarization state under the action of strong external electric fields and other factors becomes an electret.

     Polypropylene fiber material is a typical resident polar material. Its resident polarity has been widely used in the electroacoustic industry and the electronic component industry. However, the resident polarity of polypropylene fiber is also lightweight, long and short, and highly efficient. The resistance characteristics make it a better choice for air filter materials.

Electret polypropylene melt-blown non-woven fabric is to apply static electricity to the polypropylene melt-blown non-woven fabric, so as to make the fiber itself a little, and capture the dust through the charged fiber, etc., to improve the filtration efficiency.

There are two ways to improve the charge storage capacity of electret materials:

1. By improving the crystallinity and mechanical deformation of the material, the structure of the material changes, forming elongated hole channels to prevent charge drift.

2. By introducing additives with charge storage properties to generate charge traps to capture charge, the crystallinity and mechanical deformation of PP materials, such as crystallization-related auxiliary non-woven electret masterbatch, etc.