What are the representative spunbonded nonwoven fabric production processes?
At present, the representative production processes of spunbonded nonwoven fabric include wide slit suction drafting, wide slit positive pressure drafting, narrow slit positive pressure drafting, tube drafting, etc.
1.Wide slit suction draft type
This process is characterized by the use of a large spinning plate with a length equivalent to the width of the product, and an integral wide slit drafting device.
The main representative model is the reicofil process of reifenhauser company in Germany.
This is the first model introduced in China and the mainstream production process with the most application at present.
2.Wide slit positive pressure draft
This process is characterized by the use of a large spinning plate with a length equivalent to the width of the product, an independent integral wide slit drafting device and an open spinning channel.
High pressure air flow and independent draft device are used for positive pressure draft, so it has high draft speed. It can be used for many kinds of polymer processing, such as PP, pet, PA and double grouping products. It has strong adaptability to different raw materials. The disadvantage of this process is high energy consumption.
3.Narrow seam positive pressure draft type
In this non-woven fabric production line, many rectangles (such as 100mm× 600 mm), the drafting system is composed of the same number of independent drafting devices.
The size of the draft is 10mm × (width of wire feeding channel) × 600mm, the pressure of draft air flow is about 0.025mpa, and the speed is about 2000m / nin. Mechanical wire swing and mesh laying technology are adopted.
The main weakness of narrow seam positive pressure drafting process is poor product appearance, rough cloth surface, many wires, obvious wire breakage, poor uniformity of thin products, high energy consumption and production cost. This model was introduced in the 1980s and has been basically eliminated at present.
4.Tubular drafting
Tube drafting is the docan process of Lurgi company in Germany. It is characterized by round tube injection positive pressure drafting and the use of multiple small spinning plates, which can better solve the technical key problems such as filament drafting, yarn separation, mechanical swing and mesh laying.
The tubular drafting process adopts an open spinning drafting channel, which is mechanically (such as swing plate) into a network. Many independent circular tube drafting devices (with a pipe diameter of 8 ~ 16mm and a length of several meters) are used, and the positive pressure air flow is used as the drafting power. The spinning channel is fully open, and the cooling air flow has no drafting function. Generally, compressed air is used (the pressure is generally in the range of 0.2 ~ 0.8MPa), Some models can reach up to 2MPa) to realize fiber drafting.
The fiber drafting speed expressed by this round tube drafting method is high, up to 5000 ~ 7000m / min, the drafting effect is ideal, the fiber drafting is relatively sufficient, and the MD / CD * (MD is the longitudinal direction, the cloth direction; CD is the transverse and vertical cloth direction) direction strength of the product is relatively small.
It is the main production process of polyester nonwovens at present, but the product is easy to merge and break, and the appearance is slightly worse than that of slit drafting process.
In order to improve the defects of wire merging, the production process and equipment use mechanical wire splitting technology, and some also use electrostatic wire splitting technology to improve product quality.
The main disadvantages of tubular drafting are high energy consumption, large power consumption, and large draft airflow and swing noise.
