Electrostatic polarization technology
The material used as an electret air filter requires excellent dielectric properties, such as high body resistance and surface resistance, high dielectric breakdown strength, low moisture absorption, and air permeability.
This type of material is mainly composed of high polymer organic polar materials, such as non-polar materials such as polypropylene, polytetrafluoroethylene, hexafluoropropylene/tetrafluoroethylene copolymers, etc; Polar or weakly polar materials: Polytrifluoroethylene, polypropylene (blend), polyester, etc.
High melting point polypropylene resin has become the preferred material for melt blown electrostatic technology due to its excellent processing performance, low cost, and good polarizability. However, in practice, its electrostatic retention ability is greatly affected by factors such as temperature, humidity, and storage time, resulting in unstable filtration efficiency.
In order to understand the changes in the charging amount, charging speed, charge stability under different conditions, filtration efficiency, and voltage drop of static charges on the surface of meltblown fabrics, domestic and foreign researchers have conducted extensive research on the polarization process and polarization masterbatch technology.
Fluorine is the element with the highest electronegativity and has the greatest ability to “acquire electrons”. Electrons captured by fluorine atoms are not easily escaped and can effectively improve the filtration performance and service life of filter materials.
With the help of various plasma electrostatic technologies such as AC corona or DC corona, partially saturated fluorine atoms are ionized, and under some technical conditions, these fluorine particles can even partially combine with polypropylene fibers to form what is known as “hybrid” materials in the scientific research field.
Domestic institutions such as Donghua University have conducted in-depth research on the filtration performance of this hybrid material in polypropylene meltblown fabrics.
Ultra fine Organic Fluorine Electret Powder TF11
Ultra fine organic fluorine polarizing powder TF11 has a very high electrostatic capacity, and can greatly improve filtration efficiency by adding only 0.05-0.2% to meltblown fabrics. It is mainly used in the production of meltblown fabrics with filtration efficiency of 95 or 99.
Compared to other inorganic powder materials, ultrafine organic fluorine powder itself has lubricity and better compatibility with polypropylene resin, making it relatively easy to produce polar masterbatch and less likely to clog the spinneret.
Tianshi TF11 organic fluorine polar powder is very fine and has a high melting point, which can be seen as a filler during the melt spraying process. Unlike some fluorine-containing materials mentioned in literature, TF11 itself does not fibrose, and a slightly higher addition amount is expected to not affect the fineness of the melt blown fibers.
The composite of Tianshi TF11 and Molten Finger 1500 PP was used to obtain polar masterbatch. The amount of TF11 added to the polar masterbatch is 5-10%, and the addition situation is also closely related to the specific process conditions of the equipment. In principle, a slightly lower extrusion temperature will make it easier.
By mixing with PP powder, 5-15% of Tianshi TF11 organic fluorine polar powder can be directly added during the production of melt index 1500 PP to directly produce polar masterbatch.
The polar masterbatch produced according to the above method is added with 1-3% in the melt blown fabric formula, or the content of Tianshi TF11 is calculated to be around 0.1-0.2%.
Some customers have also attempted to add 0.2% Tianshi TF11 organic fluorine polar powder to PP powder through pre mixed masterbatch and other methods to produce high melting point melt blown materials with built-in polar materials.
Dongguan Liansheng Non woven Technology Co., Ltd. was established in May 2020. It is a large-scale non-woven fabric production enterprise integrating research and development, production, and sales. It can produce various colors of PP spunbond non-woven fabrics with a width of less than 3.2 meters from 9 grams to 300 grams.
Source: CHINAPLAS International Rubber and Plastic Exhibition
Post time: Dec-02-2024