PU Coating

Nature — What Is PU Coating?

PU Coating is a polyurethane layer applied to fabric to enhance waterproofness, durability, and structural stability.

It is commonly used in rainwear, bags, technical textiles, and performance outerwear.

Scientific Structure (Explained Clearly)

PU (polyurethane) coating is applied as a liquid layer to the inner side of a fabric and cured to form a flexible, water-resistant barrier. Thickness and formulation determine waterproof level and flexibility.

Structural Characteristics

  • Polyurethane coating layer
  • Applied to fabric back side
  • Cured flexible polymer film
  • Can be single or multi-layer applied

Fabric Quality Impact

  • Improves hydrostatic head rating
  • Enhances structural rigidity
  • Can reduce breathability
  • Thickness affects flexibility and weight

Performance — How PU Coating Behaves

1. Water Resistance

Provides measurable waterproof performance depending on coating thickness.

2. Flexibility

High-quality PU remains flexible without cracking under movement.

3. Durability

Resists abrasion and wear when properly formulated.

4. Breathability Trade-Off

Solid PU coatings may reduce vapor transmission compared to membranes.

Reality — What Customers Should Know

Advantages

  • Cost-effective waterproof solution
  • Flexible and lightweight compared to PVC
  • Widely used in technical applications
  • Can achieve high hydrostatic ratings

Limitations

  • May degrade over time with hydrolysis
  • Lower breathability than membrane systems
  • Performance depends on coating quality
  • Can stiffen fabric if heavily applied

Buying tip: Check hydrostatic head rating and confirm whether PU is microporous or solid for breathability expectations.

FAQ — PU Coating

Is PU coating waterproof?
Yes, when applied at sufficient thickness it provides waterproof protection.
Does PU crack over time?
Lower-quality PU can degrade or crack, especially in humid conditions.
Is PU breathable?
Solid PU coatings are less breathable than microporous membranes.
Where is PU coating used?
Rain jackets, backpacks, tents, and coated technical fabrics.