Melt blown fabric is a high-performance nonwoven material composed of ultrafine fibers. After the polymer (such as polypropylene PP) is melted at high temperature through the melt-blowing process, it is stretched into micron-level fibers by high-speed airflow and randomly stacked into a net. With its fine fiber diameter (1-5μm), high porosity and uniform distribution, it has become a core material for high-efficiency filtration, adsorption and isolation applications, especially in the fields of medical protection, air purification and sanitary products. It plays an irreplaceable role.
Core process and structural characteristics
Melt-blown technology
Process principle: After the polymer particles are melted by the screw extruder, they form a melt stream through the spinneret hole, and then are stretched into ultrafine fibers by high-temperature and high-speed airflow (air or nitrogen). After cooling, they are randomly deposited into a net, and the bonding force between fibers is enhanced by hot rolling or electret treatment.
Fiber characteristics: The fiber diameter is only 1-5μm, forming a three-dimensional network structure, the pore size is 0.5-10μm, the specific surface area is large, and it has both physical interception and electrostatic adsorption capabilities.
Electrostatic charging treatment
Through corona discharge or friction charging technology, the fiber surface carries a persistent electrostatic charge, significantly enhancing the adsorption capacity of submicron particles (such as viruses, bacteria, PM0.3), and the filtration efficiency is increased by 30%-50%.
Core performance and advantages
High-efficiency low-resistance filtration
It can intercept particles ≥0.3μm, with a filtration efficiency of 95%-99.9% (in line with N95/KN95, EN 149 or GB 2626 standards), and the initial airflow resistance is only 50-150Pa, balancing protection and breathability.
The electrostatic adsorption mechanism enables it to achieve high filtration performance at a low gram weight (25-50g/㎡) and reduce material consumption.
Multifunctional adaptability
Medical protection: middle filter layer of medical masks, protective clothing materials, blocking droplets and pathogenic microorganisms.
Industrial purification: air filter (HEPA pre-filter layer), oil mist separator, car cabin filter element.
Hygiene and environmental protection: oil-absorbing cotton, sanitary napkin/diaper surface guide material, water treatment filter membrane support layer.
Chemical stability and safety
Polypropylene substrate is acid and alkali resistant, non-toxic and odorless, and meets FDA, RoHS and other biocompatibility requirements.
Flame-retardant models can achieve UL94 V-0 fire protection standards by adding additives.
Typical application scenarios
Medical health:
N95/KN95 mask core filter layer, which has become a key global epidemic prevention material during the COVID-19 epidemic.
Surgical gowns and disinfection wraps to prevent liquid penetration and microbial transmission.
Air purification:
HEPA filter pre-stage pre-filtration to extend the life of high-efficiency filter elements.
Home purifiers, fresh air systems, remove PM2.5, pollen and allergens.
Industrial protection:
Dust-free workshops, particle control in semiconductor manufacturing.
Pre-filtration of paint mist in automotive spray workshops to protect precision equipment.
Environmental protection and daily necessities:
Oil cleaning felt, industrial oil absorption materials, and oil spill handling.
Sanitary product diversion layer to improve liquid absorption speed and uniformity.
Selection and production points
Key parameter selection
Filtration efficiency: Select the electret process and gram weight (usually 25-50g/㎡) according to the target particle size (such as virus 0.1μm, PM2.5 2.5μm).
Resistance and air permeability: Increasing gram weight can improve efficiency, but it will increase the pressure difference, and it needs to be designed according to the fan power balance.
Antibacterial function: Add silver ion or copper ion coating to enhance the ability to resist microbial growth.
Quality control
Electret effect stability: Avoid storage in high temperature and high humidity environment to prevent static charge decay and reduce efficiency.
Uniformity detection: Ensure that the fiber mesh is defect-free through pore size distribution test and air permeability instrument.
Sustainable development
Degradable modification: Develop PLA (polylactic acid) based meltblown cloth to reduce plastic pollution.
Recycling: Recycle waste meltblown cloth and granulate it for low-end fiber products.
Meltblown cloth, with “ultrafine fiber + electrostatic adsorption” as its core technical barrier, has become the cornerstone material in the field of high-precision filtration. With the integration of nanocomposite, biodegradable and other technologies, its application scenarios are extending from traditional protection to high-end fields such as smart wearables and new energy battery separators, continuously promoting the collaborative innovation of material science and industrial needs.
