Masterbatch usage nano grade white tourmaline powder
Micro tourmaline powder can be used as electret material. Electrets are electrolyte materials with long-term charge storage function. Electret methods include electrospinning, corona charging, friction electrification, thermal polarization and low energy electron beam bombardment. Tourmaline electret material uses corona charging method to make the fiber with a certain amount of charge, giving the electrostatic filtering function.
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 slender holes to prevent charge drift.
2. By introducing additives with charge storage properties, charge traps are generated to capture charge.
The polarization of electrets made of nonpolar materials is mainly caused by space charge. There are two types of space charges: one is called the same sign charge, and the other is called the different sign charge. The former is due to the existence of conductivity between the dielectric and the electrode or electric breakdown near the dielectric surface under the action of strong electric field, which makes the electrode inject charge into the dielectric; the polarity of the injected space charge is the same as that of the adjacent electrode. The polarity of the charge with different sign is opposite to that of the adjacent electrode, which is mainly due to the charge separation and capture in the dielectric. The electret charge formed by dipole orientation in polar dielectrics is another type of charge with different sign.
The addition of tourmaline particles can effectively improve the electret efficiency, increase the filtration efficiency, reduce the filtration resistance, increase the surface charge density of the fiber, and enhance the charge storage capacity of the fiber web. Adding 6% tourmaline electret has better comprehensive effect. Too many electret materials will increase the mobility and neutralization of carriers.
The process of melt blown electrostatic electret is to add tourmaline, silicon dioxide, zirconium phosphate and other inorganic materials into PP polypropylene polymer in advance, and then charge the melt blown materials by one or more groups of corona discharge with the needle electrode voltage of 5-10kv of electrostatic generator before rolling cloth. When high voltage is applied, the air under the needle tip will produce corona ionization, and produce partial breakdown discharge, and the carriers will pass through Under the action of over electric field, a part of the carriers will be trapped by the electret masterbatch, which makes the meltblown cloth become electret filter material.