HYFabricsupply is a professional non-woven fabric manufacturer of high quality Polypropylene Non-woven Fabric, Polyester spunbonded non-woven fabric, Spunlaced non-woven fabric,and more.
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Polyester fiber (polyester fiber, PET fiber) is one of the most widely used synthetic fibers in the production of spunlace nonwovens. With its excellent mechanical properties, chemical stability, and good compatibility with the spunlace process, it has become the core raw material for mid-to-high-end spunlace fabrics. The following is an analysis from the aspects of fiber characteristics, types, and role in the spunlace process:
High Strength and Wear Resistance
The breaking strength of polyester fiber can reach 3-5cN/dtex, and the wet strength retention rate is ≥90% (much higher than the wet strength loss of cotton fiber). It is not easy to break under the violent impact of high-pressure spunlacing (50-300bar), and can maintain the structural integrity of the fiber web. At the same time, its wear resistance is more than 3 times that of cotton, making spunlace nonwovens suitable for repeated wiping scenarios (such as industrial rags, wet wipes).
Excellent Chemical Stability
It is resistant to acids, alkalis, and organic solvents (such as alcohol, detergents). It has stable performance during washing and post-treatment (such as hydrophilic and antibacterial finishing) in the spunlace production, and will not cause strength reduction due to hydrolysis or chemical reactions. This characteristic makes it particularly suitable for medical (need to contact disinfectants), industrial filtration (contact with corrosive media) and other scenarios.
Low Hygroscopicity but Modifiable
Polyester itself has poor hygroscopicity (moisture regain is only 0.4%), but by adding hydrophilic groups during spinning or post-treatment (such as plasma modification), the water absorption time of spunlace fabric can be shortened to within 3 seconds, meeting the skin-friendly needs of hygiene products (such as wet wipes, facial cleansers). Unmodified polyester is suitable for scenarios requiring water resistance (such as protective fabrics).
Thermal Stability Adapts to Spunlace Post-Treatment
The melting point of polyester is about 255-265℃, which is much higher than the drying temperature (100-130℃) after spunlacing. It will not melt and deform during the drying process, ensuring the dimensional stability of nonwovens (thermal shrinkage rate ≤2%).
According to the differences in fiber morphology and performance, polyester fibers commonly used in the spunlace process can be divided into:
Regular Polyester Staple Fibers
Length: 38-76mm (51mm is commonly used in the spunlace process to balance web uniformity and entanglement efficiency);
Linear density: 1.1-3.3dtex (fine denier fibers such as 1.1-1.7dtex are used for soft fabrics, and coarse denier fibers such as 3.3dtex are used for high-strength fabrics);
Morphology: Mostly crimped fibers (8-12 crimps/25mm). Mechanical crimping increases the cohesion between fibers and reduces fiber slippage during spunlacing.
Superfine Polyester Staple Fibers (Microdenier Fibers)
Linear density ≤0.8dtex (such as 0.5dtex), fiber diameter is only 5-10μm, which can form a denser fiber web, endowing spunlace fabrics with a delicate touch (such as the "silk-like feel" of mask base cloth) and high filtration efficiency (air filtration efficiency ≥90%@0.3μm).
It needs to be matched with low spunlace pressure (50-150bar) to avoid excessive breakage of superfine fibers leading to linting.
Bicomponent Polyester Fibers (Core-Sheath Structure)
The sheath is low-melting copolyester (melting point 110-180℃), and the core is regular PET (melting point 255℃);
After spunlacing, hot air reinforcement (120-160℃) can melt the sheath, further improving the fabric strength (20%-30% higher than pure mechanical entanglement strength), suitable for products with high strength requirements (such as geotextiles, automotive interior fabrics).
Fiber Parameters | Influence on Spunlace Fabric Performance | Optimized Selection for Typical Application Scenarios |
Linear Density (dtex) | Fine denier fibers → soft, high air permeability (air permeability ≥3000L/m²·h); Coarse denier → stiff, high strength | Mask cloth selects 1.1dtex; Industrial rags select 3.3dtex |
Length (mm) | Too short (<38mm) → insufficient entanglement and easy linting; Too long (>76mm) → uneven web laying | Sanitary fabrics select 51mm; Thick fabrics (≥80g/m²) select 64mm |
Crimp Degree (counts/25mm) | Insufficient crimp → poor fiber cohesion, easy pilling on the fabric surface; Excessive crimp → reduced air permeability | Regular spunlace fabrics select 8-10 counts; High air permeability fabrics select 6-8 counts |
Cross-Sectional Shape (Round/Irregular) | Irregular cross-section (such as trilobal) → larger specific surface area, hygroscopicity and air permeability increased by more than 30% | Wet wipes and filter cloths select irregular fibers; Regular fabrics use round fibers |
Pure Polyester Spunlace Fabrics (100% polyester):
They rely on high fiber entanglement to achieve strength, suitable for industrial filtration (such as air conditioning filters) and wiping cloths (dust-free cloths in electronics factories). The weight is usually 30-100g/m², and high-strength polyester with a breaking strength ≥4cN/dtex should be selected.
Polyester-Cotton Blended Spunlace Fabrics (50%-80% polyester + 20%-50% cotton):
Polyester is used to enhance wear resistance, and cotton improves skin-friendliness, which are often used in baby wet wipes and facial cleansers. Among them, polyester preferably selects 1.5dtex fine denier fibers to balance softness and strength.
Composite of Polyester and Functional Fibers:
Such as polyester + bamboo fiber (antibacterial), polyester + ES fiber (hot-melt reinforcement). Through the skeleton effect of polyester, the dimensional stability of the composite fabric is improved, avoiding excessive shrinkage of other fibers (such as bamboo fiber) after spunlacing (shrinkage rate can be controlled within 1%).
Adaptation to Spunlace Pressure: For fine denier polyester (≤1.7dtex), the recommended spunlace pressure is ≤200bar; for coarse denier polyester (≥3dtex), it can withstand high pressure of 250-300bar to enhance entanglement;
Cost Balance: Regular polyester staple fibers are cheaper than superfine denier and bicomponent fibers, suitable for the mass market; high-end products (such as medical beauty mask cloths) require superfine denier polyester to improve texture;
Environmental Requirements: Recycled polyester (rPET fiber) can be selected, which has the same performance as virgin polyester, meets EU environmental regulations (such as REACH), and is suitable for export-oriented spunlace fabrics.
In conclusion, polyester fiber can accurately match the performance requirements of spunlace nonwovens through parameter adjustment (linear density, length, morphology). It is the optimal solution to balance "strength, durability, and cost" and occupies an irreplaceable position in the fields of hygiene, medical care, and industry.
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