In the hygiene products industry, nonwoven fabrics serve as critical foundational materials. From baby diapers and sanitary napkins to adult incontinence care products, pet pee pads, and medical care products, nonwovens are widely utilized across various structural layers.
Depending on the manufacturing process, nonwoven fabrics can be categorized into spunbond, through-air bonded, spunlace, and meltblown nonwovens. Among these, spunbond nonwovens boast an exceptionally broad range of applications. Characterized by high production efficiency, superior strength, lightweight properties, and excellent breathability, they are extensively used in sectors including hygiene products, medical supplies, packaging, and agriculture.
What is Spunbond Nonwoven?
Spunbond nonwoven, also known as spunbonded nonwoven fabric, differs from spunlace nonwovens (which rely on high-pressure water jets for fiber entanglement). Instead, spunbond nonwovens are produced by melt-extruding polymer raw materials into continuous filaments, which are then stretched, laid into a web, and bonded together.
Simply put, the process can be understood as:
Melting plastic pellets → Drawing them into ultra-fine continuous filaments → Laying them into a web → Bonding the fibers together.
Because the spunbond process produces continuous filaments, the fiber length is significantly greater than that of staple fiber nonwovens, typically resulting in materials with excellent machine-direction and cross-directional strength.
How is Spunbond Nonwoven Produced?
The production process primarily involves raw material preparation, melt extrusion, spinning, stretching, web formation, and bonding.
1. Raw Material Preparation
Common raw materials include thermoplastic polymers such as polypropylene (PP) and polyester (PET). In the hygiene sector, PP is particularly prevalent. Depending on the desired performance of the final product, material softness, hydrophilicity, and breathability can be adjusted through different polymer formulations, fiber structures, and functional masterbatches.
2. Melt Extrusion
The treated polymer enters an extruder. Under the combined action of heat and screw shearing, the solid polymer gradually melts into a uniform melt, which is then transported to the spinning assembly for subsequent processing.
3. Spinning
The molten polymer is extruded through microscopic spinneret holes to form numerous continuous fine filaments. These fibers are typically extremely thin, creating a lightweight fibrous structure. This step is crucial, as spinning quality directly impacts the uniformity and performance of the final product.
4. Stretching
The newly formed continuous filaments undergo further stretching via high-speed airflows or mechanical drafting. This makes the fibers finer while improving their strength and uniformity. Finer fibers enable the formation of a more uniform fibrous network at the same basis weight.
5. Web Formation
The stretched continuous filaments are laid onto a forming belt to create a uniform fiber web. Unlike traditional textile processes, spunbond nonwovens do not require spinning fibers into yarns before weaving; the material structure is formed directly from fibers. This allows for a highly continuous production process and high efficiency.
6. Bonding
Once the web is formed, it must be bonded to create a stable structure. A common method is thermal calendering, where heat and pressure create bonding points between fibers, thereby enhancing the material's strength and dimensional stability.
After bonding, the material is slit, wound into rolls, and undergoes further processing to become the final spunbond nonwoven product.
Key Characteristics of Spunbond Nonwovens
1. Superior Strength: The continuous filament structure forms a stable network, providing excellent tensile and tear strength. This is a significant advantage for hygiene products requiring structural support.
2. Lightweight: By adjusting fiber fineness and basis weight, lightweight production is achievable. As the hygiene industry increasingly emphasizes "thinness," lightweight nonwovens hold immense application value.
3. Excellent Breathability: The abundant micropores between fibers create air channels. With proper design, spunbond nonwovens can balance strength and breathability, making them ideal for structures requiring ventilation.
4. High Production Efficiency: As a continuous manufacturing process-from melting and spinning to web formation and bonding-it offers high efficiency and is well-suited for large-scale production compared to traditional staple fiber processes.
5. Functionalization Potential: By adding specific functional materials or applying post-treatments, properties such as hydrophilicity, hydrophobicity, and softness can be tailored to meet diverse application scenarios.
Applications in Hygiene Products
1. Baby Diapers: A major application area. Spunbond nonwovens are used in back sheets, waistbands, side panels, and standing leg cuffs. Hydrophilic-treated spunbond materials can also be utilized in specific liquid distribution layers.
2. Feminine Hygiene Products: Used in back sheets, side edges, and structural layers. By varying basis weight, fiber fineness, and post-treatment processes, manufacturers can meet diverse requirements for softness, breathability, and strength.
3. Adult Incontinence Care: Products like adult diapers and pull-ups demand high breathability, softness, and structural stability. Spunbond nonwovens are vital for outer layers, waistbands, and leg cuffs.
4. Pet Care Products: With the growth of the pet hygiene market, pet pee pads and diapers increasingly require lightweight, breathable, and strong materials, driving greater adoption of spunbond nonwovens.
Spunbond vs. Through-Air Bonded vs. Spunlace
While all are nonwovens, their production principles and characteristics differ significantly:
Spunbond: Formed by directly spinning polymer melt into continuous filaments. Excels in strength, lightweight properties, and production efficiency.
Through-Air Bonded: Uses hot air to melt low-melting-point or bicomponent fibers. Known for high bulk and extreme softness; widely used in absorbent hygiene products.
Spunlace: Uses high-pressure water jets for fiber entanglement. Offers superior softness, absorbency, and wet strength; predominantly used in wet wipes and dry towels.
In short, spunbond focuses on strength and lightness, through-air bonding emphasizes bulk and softness, and spunlace highlights softness, absorbency, and wiping experience. In actual hygiene product manufacturing, no single material is universally superior; the choice depends on product structure, cost, performance, and end-user needs.
Future Development Trends
As hygiene products evolve toward thinner, high-performance, and functional designs, spunbond nonwovens are continuously upgrading. Finer fibers, lower basis weights, and more uniform web structures are meeting the demand for thinness. Simultaneously, softness has become a key focus. Historically emphasizing strength and efficiency, material manufacturers are now prioritizing tactile feel, skin-friendliness, and consumer experience. Additionally, sustainability is a major trend, with ongoing efforts to reduce basis weight, improve efficiency, and develop recyclable or eco-friendly raw material systems.