Based on knowledge up to July 2024, nonwoven fabrics are the primary material used in disposable pet pads (pee pads, puppy pads, incontinence pads) due to their excellent combination of properties. Here's a breakdown of their key roles and characteristics:

Absorption: The core layer (often a blend of fluff pulp and superabsorbent polymers - SAP) is wrapped in or covered by nonwoven fabrics (like airlaid or carded thermalbond) to contain the SAP and facilitate liquid wicking.

Leak Prevention: A critical bottom layer (backsheet) is made from a liquid-impermeable nonwoven, typically a polypropylene (PP) or polyethylene (PE) film laminated to a spunbond nonwoven, or a SMS (Spunbond-Meltblown-Spunbond) nonwoven. This prevents leaks onto floors or furniture.

Top Layer (Coverstock): The layer directly in contact with the pet's paws. This is usually a soft, hydrophilic (water-attracting) nonwoven (often spunbond PP or carded thermalbond PP/PET) designed to quickly draw liquid away from the surface ("dry-feel") and into the absorbent core. It needs to be gentle on paws.

Spunbond (S): Made by extruding continuous filaments. Used for coverstock (softness) and as the outer layer of backsheets (strength, barrier when combined with film or meltblown). PP spunbond is most common.

Meltblown (M): Made from microfibers. Often used in SMS structures as the middle barrier layer for excellent liquid resistance without needing a film.

SMS (Spunbond-Meltblown-Spunbond): A premium composite. The meltblown middle layer provides a highly effective liquid barrier, while the spunbond layers offer strength and softness. Widely used for backsheets.

Airlaid: Made by air-depositing short fibers (often wood pulp blended with SAP or synthetic fibers). Primarily used within the absorbent core structure.

Carded Thermalbond: Made from carded staple fibers bonded with heat. Used for coverstock and sometimes core wrap. Can offer good softness and bulk.

High Absorbency Rate & Capacity (Coverstock & Core Wrap): Must wick liquid quickly.

Liquid Impermeability (Backsheet): Absolute barrier to prevent leaks.

Dry-Feel Surface (Coverstock): Hydrophilic treatment allows liquid to pass through quickly, leaving the surface relatively dry.

Softness & Non-Irritating (Coverstock): Comfort for sensitive paws.

Strength (Wet & Dry): Must withstand pet movement, scratching, and remain intact when saturated.

Odor Control: Some nonwovens incorporate additives or specific treatments to help neutralize ammonia odors.

Cost-Effectiveness: Disposable nature requires economical materials and efficient manufacturing.

Polypropylene (PP): Dominant material due to cost, chemical resistance, and processability. Used in spunbond, meltblown, SMS, and thermalbond fabrics.

Polyester (PET): Sometimes used in coverstock or thermalbond blends for added strength or softness.

Wood Pulp: The primary absorbent fiber in the core, often wrapped in or mixed with nonwovens.

Superabsorbent Polymer (SAP): Granules held within the core structure, often contained by nonwoven wraps.

Polyethylene (PE) Film: Laminated to spunbond for traditional backsheets (though SMS is increasingly replacing this).

Biodegradable or compostable nonwovens (e.g., PLA spunbond, viscose/pulp blends) are emerging but face challenges in cost and performance compared to PP.

Recycled PP content is being explored in some nonwovens.

Reducing overall material usage (basis weight) while maintaining performance is a constant focus.

In summary: Nonwoven fabrics are indispensable in pet pads, providing the critical functions of rapid liquid intake (coverstock), massive absorption and containment (core wrap), and leak-proof protection (backsheet), all while being soft, strong, and cost-effective enough for disposable use. Spunbond PP, SMS composites, and airlaid/carded core materials are the workhorses of this application.