Process Flow of Meltblown Production Line
The melt-blown process uses high-speed hot air to draw a thin stream of polymer melt extruded from the die orifice, thereby forming ultra-fine fibers and condensing on the screen or roller, and relying on self-adhesion and become a non-woven fabric.
The process flow is:
Polymer mixing -> Melt extrusion -> Filter -> Melt pump -> Die -> Electret treatment -> Winding system
Equipment List of Meltblown Fabric Production Line
· Resin Dryer/Resin Transfer Machine
· Screw Extruder
· Gear Pump Unit
· Heating System for Hot Air
· Melt-blown Box (T-Die, Distribution, Spinneret)
· Collection Device (Conveyor or Drum)
· Winding Machine
· High-voltage Electrostatic Electret Device
What is Melt-blown Fabric?
Meltblown fabric is a non-woven fabric made by melt blown method with high MFI (1200/1500/1800 g/10min, Condition 2.16kg, 230°C) PP as the main raw material.
The melt blown method is a spinning method that uses a high-speed hot air flow to rapidly stretch, solidify, and shape a polymer melt that has just been extruded. The advantage is that the process flow is short, and the non-woven fabric can be directly produced by spinning.
The fiber diameter of the melt-blown cloth can reach 1 to 5 microns. With many voids, fluffy structure, and good fold resistance, these ultra-fine fibers with unique capillary structure increase the number and surface area of fibers per unit area, thus making the melt-blown cloth have good filtering, shielding, heat insulation, and oil absorption .
The most important reason why the melt-blown fabric is much better than ordinary non-woven fabrics is the electret treatment. Through electret treatment, the PP meltblown fabric is charged with static electricity, which can effectively absorb and block viruses.
Melt-blown Fabric Applications
· Medical and sanitary cloths: surgical gowns, protective clothing, sterilization wraps, masks, diapers, sanitary napkins, etc.
· Fabrics for home decoration: wall stickers, tablecloths, bed sheets, bed covers, etc.
· Cloth for clothing: lining, adhesive lining, flakes, shaped cotton, various synthetic leather base fabrics, etc.
· Industrial fabrics: filter materials, HEPA filter, insulating materials, cement bags, geotextiles, covering fabrics, etc.
· Agricultural cloth: crop protection cloth, seedling raising cloth, irrigation cloth, thermal insulation curtain, etc.
· Others: space cotton, thermal insulation and sound insulation materials, linoleum, cigarette filter, tea bags, etc.
Factors Affecting the Quality of Meltblown Fabric
1. MFI of Polymer Raw Materials
Meltblown fabric is the best filter for masks. It is a very fine material. The inside is made up of a lot of crisscross microfibers stacked in random directions. Taking PP as an example, the higher the MFI, the finer the wire drawn during melt-blown processing, and the better the filtration performance.
2. Hot Air Velocity
Under the same temperature, screw speed and receiving distance (DCD) and other conditions, the faster the hot air speed, the smaller the fiber diameter, the non-woven fabric feels softer, and the more fiber entanglement, resulting in more dense and smooth fiber web Strength increased.
3. Hot Air Jet Angle
The hot air jet angle mainly affects the drawing effect and fiber morphology. The smaller angle will cause the fine flow to form parallel fiber bundles, resulting in poor uniformity of the non-woven fabric. If the angle tends to 90°, a highly dispersed and turbulent air flow will be generated, which is conducive to the random distribution of fibers on the screen curtain, and the resulting melt-blown cloth has good anisotropy.
4. Receive Distance (DCD)
Too long acceptance distance will lead to a decrease in the vertical and horizontal strength and bending strength, the non-woven fabric feels fluffy, and in the melt-blown process will lead to a reduction in filtration efficiency and filtration resistance.
5. Screw Extrusion Speed
Under the condition of constant temperature, the screw extrusion rate should be kept within a certain range. Before a certain critical point, the faster the extrusion speed, the higher the quantitative amount of melt-blown cloth, and the greater the strength; when the critical value is exceeded, the strength of the melt-blown cloth decreases.
Meltblown Fabric Final Product
The final melt blown fabric produced by our production line can be BFE95 (Bacterial Filtration Efficiency), however the testing result is better than BFE98.