The Quality and Manufacturing Process of UD-PE Nonwoven Fabric

The quality foundation of UD-PE (Unidirectionally Drawn Polyethylene) nonwoven fabric originates from the strict selection of ultra-high molecular weight polyethylene (UHMWPE) chips. Raw materials with stable melt flow rate and uniform molecular weight distribution are carefully chosen. These materials have a crystallinity of over 85%, which not only provides excellent tear resistance but also endows the final product with outstanding chemical stability and weather resistance. The raw materials undergo vacuum drying treatment to remove trace moisture (moisture content ≤ 0.05%), preventing the formation of bubble defects during the spinning process and ensuring the smooth progress of subsequent processes.

Core Process: Precise Transformation from Melt to Oriented Fibers

1. Melt Spinning: A Key Step in Filament Formation

The dried UD-PE chips are fed into a screw extruder, where they are uniformly melted through gradient temperature rise (180-220℃). The molten PE is precisely controlled in terms of output volume (error ≤ ±1%) by a metering pump and then enters the microhole array of the spinneret (hole diameter: 0.2-0.5mm), forming continuous and uniform molten filaments. At this point, high-speed cooling air (air speed: 3-5m/s) blows vertically onto the filaments, causing them to solidify rapidly into as-spun fibers. The diameter of the fibers is controlled within the range of 10-30μm, ensuring the fineness and flexibility of the fibers.

2. Unidirectional Stretching: Endowing Fibers with Oriented Strength

After being stretched by draw rolls, the as-spun fibers enter a unidirectional stretching unit, which is the core technological highlight of UD-PE nonwoven fabric. Through the speed difference of multiple sets of draw rolls (draw ratio: 8-12 times), the fibers are forced to stretch in the longitudinal direction, and the molecular chains are highly oriented and arranged along the stress direction. The strength of the oriented fibers is 3-5 times higher than that of the unstretched fibers, with a breaking strength of 20-30cN/dtex. The longitudinal tensile modulus is significantly improved, laying a core foundation for the unidirectional load-bearing performance of the final product.

3. Web Formation and Bonding: The Molding Process for Structural Stability

The fiber bundles after unidirectional stretching are evenly spread into a continuous fiber web by a web-laying machine. Different from traditional nonwoven fabrics, UD-PE nonwoven fabric adopts a thermal bonding process. Through the precise temperature control (120-140℃) and pressure adjustment (0.3-0.5MPa) of hot press rolls, the surface of the fiber web is partially melted and bonded, forming a nonwoven substrate with stable structure. During the thermal bonding process, temperature and pressure are strictly controlled to not only ensure bonding strength but also avoid performance degradation caused by excessive melting of fibers.

Core Process Advantages and Product Characteristics

Oriented Toughness: The unidirectional stretching process enables the oriented arrangement of fiber molecules. The longitudinal breaking strength of the final product is 3-5 times that of ordinary PE nonwoven fabric, with excellent tear resistance, making it suitable for scenarios requiring high-strength load-bearing.

Lightweight and Environmentally Friendly: The raw material is polyethylene, with a density of only 0.94g/cm³. The grammage of the final product can be controlled within 20-200g/㎡, combining light weight and high strength. Moreover, it is recyclable, meeting environmental protection requirements.

Stability and Reliability: The entire process is controlled automatically (key parameters such as temperature, pressure, and draw ratio are monitored in real time). The product qualification rate is over 99%, and there is little performance fluctuation.

Multifunctional Adaptability: By adjusting the raw material formula, draw ratio, and post-treatment process, multi-specification products ranging from lightweight types (for medical protection and military bulletproofing) to heavy-duty types (for industrial use) can be produced to meet the needs of different fields.