Waterproof fabrics are essential in modern baby products, particularly reusable diapers, changing pads, and bibs. Among available materials, PUL (Polyurethane Laminate) and TPU (Thermoplastic Polyurethane) are the most commonly used. While both serve the same waterproofing function, they differ in structure, manufacturing method, and long-term performance. This guide outlines the technical distinctions between PUL and TPU and helps manufacturers, brands, and parents make informed material decisions.
What Is PUL?
PUL is a composite fabric consisting of a textile base—typically polyester—bonded to a thin polyurethane film. It is valued for being waterproof, flexible, and relatively lightweight. PUL is used in products that require both softness and moisture protection, such as cloth diaper covers, mattress protectors, and medical gowns.
What Is TPU?
TPU refers to the thermoplastic polyurethane film used in the lamination process. It is not a fabric by itself but becomes part of PUL when heat-bonded to a textile. TPU is known for its elasticity, softness, and improved environmental profile compared to traditional polyurethane films.
Manufacturing Methods
The performance and environmental characteristics of PUL largely depend on the lamination technique used:
1. Solvent Lamination (Traditional PUL)
TPU film is bonded to fabric using chemical solvents.
Creates durable bonds that resist boiling and industrial washing.
Involves VOC emissions and chemical waste disposal.
Still used in some medical-grade applications.
2. Heat Lamination (Modern TPU-Based PUL)
Utilizes heat and pressure, without solvents or adhesives.
Yields a softer, quieter, and more flexible fabric.
Produces no harmful emissions during bonding.
Has become the standard in most reusable baby product brands since 2010.
Material Comparison
| Property | Solvent-Laminated PUL | Heat-Laminated TPU-PUL |
|---|---|---|
| Waterproof Performance | Excellent | Excellent |
| Flexibility | Moderate | High |
| Breathability | Low | Moderate |
| Durability (Heat) | High—resists boiling, autoclaving | Moderate—avoid excessive heat |
| Environmental Impact | Chemical use, VOC emissions | Low impact, no solvent use |
| Feel & Texture | Slightly stiff | Soft, cloth-like |
| Typical Use Cases | Medical covers, industrial wear | Baby diapers, pads, apparel linings |
Typical Applications
Both PUL types are used in baby care, but specific use cases differ:
Solvent-Laminated PUL
Suitable for environments requiring high-temperature sterilization or industrial-grade washing, such as hospitals or institutions.
- TPU-Based PUL (Heat-Laminated)
Ideal for everyday consumer baby products where softness, quietness, and sustainability are desired. Common in reusable diapers, wet bags, nursing pads, and change mats.
Maintenance Considerations
Proper care extends the life of both materials, especially TPU-laminated PUL:
Wash at ≤ 60°C; avoid sanitize or boil cycles.
Do not bleach or use borax-based detergents.
Air dry only—do not tumble dry diaper shells or TPU-laminated items.
Avoid wringing or overstretching laminated areas.
Neglecting care instructions may result in delamination, particularly in heat-bonded products.
Conclusion
Both solvent-laminated PUL and heat-laminated TPU-based PUL provide reliable waterproof performance. However, they serve different purposes:
For comfort-focused, baby-safe applications, heat-laminated TPU-PUL is the recommended choice due to its softness, moderate breathability, and eco-friendliness.
For high-temperature sterilization or extended durability, solvent-laminated PUL remains the better option.
Selecting the right material depends on product design priorities—whether softness and sustainability or rugged performance is the main objective.
