The correlation logic between Daniel and Kezhong
1. Key Definition Analysis
Denier (D): A measure of fiber linear density, referring to the weight (in grams) of 9000 meters of fiber at a predetermined moisture regain. The commonly used single filament denier range for polyester spunbond is 1.5D-15D, with higher values indicating thicker fibers. Weight (g/m ²): The weight per unit area of non-woven fabric, which directly reflects the thickness and density of the material. The conventional weight range for polyester spunbond is 10g/m ² -300g/m ².
2. The intrinsic connection between the two
Mathematical relationship: Weight ≈ Denier per filament x Number of fibers x Fiber length/Unit area, which can be simplified as weight ∝ Denier x Spinning amount/Web forming speed in spunbond technology. Practice rule: Under the same process, for every 1D increase in single filament denier, the weight increases by about 5-8g/m ² (taking 80g/m ² as an example); If the denier remains unchanged, the spinning volume increases by 20%, and the weight increases synchronously by 18-22%.
Core concept analysis
Online Composite:
Definition: On the same continuous production line for polyester spunbond nonwoven fabric, the process of functional addition or composite is directly completed after fiber web formation and before winding.Characteristics: Integration, continuity, and high efficiency. It is a functional extension of one-step production.Typical techniques: online spraying, online rolling liquid, online hot pressing composite, online lamination (directly composite with the just spun fiber web).
Offline Composite:
Definition: Functional processing or composite with other materials is carried out on the already produced base fabric roll by independent subsequent processing equipment.Features: Strong flexibility, multiple technical options, and the ability to produce in small batches. It is a ‘two-step’ or ‘multi-step’ method.Typical techniques: immersion coating, scraper coating, transfer coating, hot melt adhesive composite, flame composite, ultrasonic composite, etc.
Why is “combining online and offline” the critical path?
Relying solely on online or offline methods has its limitations:
Only relying on online compounding: single function, difficult to add functional additives sensitive to high temperature, pH value or shear force (such as some biological enzymes, polymer lotion), difficult equipment transformation, inflexible product transformation.Relying solely on offline compounding: production process breakage, low efficiency, increased cost (additional winding, transportation, and rewinding processes), which may affect the hand feel and mechanical properties of the base fabric.
Therefore, combining the two organically, leveraging their respective strengths, and avoiding their weaknesses has become the most effective strategy to enhance the functionality of polyester non-woven fabrics
Online composite endows the base fabric with basic, universal, and high-temperature resistant functionality.On this basis, offline composite processing is carried out for high-end, fine, and composite deep processing.
Specific implementation and technical means of critical path
Path 1: Creating high-performance base fabrics through “online composite”
This is the underlying foundation for enhancing functionality. The goal is to manufacture high starting point substrates on the production line that are different from ordinary non-woven fabrics.
Online function masterbatch addition:
Technology: In the screw extrusion stage, melt spinning is achieved by blending functional masterbatch with polyester chips.
Implementation functions: UV resistant, antibacterial (silver ions, zinc ions, etc.), hydrophilic (permanent hydrophilic agent), flame retardant (phosphorus based, nitrogen based flame retardant), color masterbatch (coloring), etc.
Advantages: Uniform functionality, good durability (not easy to wash away).
Online spraying/impregnation:
Technology: Functional finishing agents are applied through nozzles or rolling troughs after the fiber web is formed and before hot rolling reinforcement.
Implementation functions: hydrophilic finishing (used for medical and health materials to accelerate liquid penetration), anti-static finishing, soft and smooth hand feel finishing.
Advantages: Simple process, relatively low cost, and perfect integration with production lines.
Online lamination/composite:
Technology: Integrating multiple web forming systems or unwinding devices in the production line, directly hot rolling and laminating polyester spunbond webs with melt blown webs (SMS) or other films (such as PE films).
Implementation function: Prepare high barrier SMS materials (used for medical protective clothing, disinfectant bags), waterproof and breathable composite materials.
Advantages: One step production, combined with high strength and unbeatable efficiency.
Path 2: Implementing High Value Added Functions through “Offline Composite”
This is a “precision processing” and “recreation” carried out on high-quality base fabric.
Functional coating:
Technology: Use scraper, roller coating and other methods to apply functional coatings on the base fabric.
Implementation function:
PU/PA coating: waterproof, breathable, windproof, and soft to the touch (used for outdoor clothing and tents).
TPU/TPE coating: high elasticity, wear-resistant (used for sports shoe materials, backpacks).
Fluorocarbon coating: super water repellent and oil repellent (used for high protection industrial wiping cloths).
Special functional coatings: conductive coatings (for electromagnetic shielding), phase change material coatings (for temperature regulating fabrics), photocatalytic coatings (for self-cleaning materials).
Adhesive Composite:
Technology: Using adhesives such as hot melt adhesive and water-based adhesive to composite non-woven fabric with another material.
Implementation function:
Composite with film: further enhance barrier properties (medical packaging) and waterproofness (building waterproofing membrane).
Composite with another non-woven fabric: Combining the advantages of two materials, such as the strength of spunbond fabric and the filtration of meltblown fabric (to produce high-end filter materials).
Composite with fabric/sponge: used for automotive interiors and household items to enhance aesthetics and comfort.
Immersion treatment:
Technology: Fully immerse the base fabric in functional liquid for treatment.
Implementation functions: flame retardant treatment (used for decorative materials in public places), resin reinforcement (used for synthetic leather fabrics, enhancing dimensional stability).
Conclusions and Prospects
The most core and critical path to enhance the functionality of polyester spunbond nonwoven fabrics is to create basic functional base fabrics through online composite and achieve high-end customized functions through offline composite. Enterprises are committed to developing more efficient and precise online additive systems (such as more uniform online spraying systems), as well as more environmentally friendly and high-performance offline composite technologies (such as solvent-free composite and laser composite).
Future direction: Intelligent production lines will achieve seamless integration between “online” and “offline”. Through big data and the Internet of Things, according to the personalized requirements of offline orders, the online process parameters are automatically adjusted to produce the most suitable base fabric, which is then guided to the corresponding offline composite unit, ultimately achieving large-scale, low-cost, and personalized production of high-performance non-woven fabrics.
This composite path not only meets the growing demand for multifunctional and high-performance non-woven fabrics in the market, but also promotes the transformation and upgrading of the entire polyester spunbond industry from scale oriented to technology value and innovation oriented.
Post time: Sep-22-2025