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What is PUL fabric?

“Polyurethane Laminate Fabric,” or PUL, is a soft, flexible, hardwearing, and water-resistant fabric.

PUL is a laminate fabric comprised of two layers:

  • a polyester fabric (typically 1mm thick) with a
  • very thin layer of polyurethane film bonded to the reverse.

Polyester is preferred to cotton because it is difficult to have a truly water-resistant product using cotton.

The polyester side can be plain or printed with a design. It will retain its stretchability even with the additional polyurethane layer. This makes for an extremely resilient fabric which will last for many years.

It’s important to note that PUL remains supple and soft to the touch, unlike a cotton fabric backed with a separate plastic fabric or an ‘oil cloth’ type fabric.

These characteristics make PUL the ideal fabric for our range of lunch bags and reusable freezer bags.

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Manufacturing Eco-PUL

We use Eco-PUL exclusively. The polyester jersey and polyurethane film are bonded using heat and pressure with a solvent-free adhesive, rather than a solvent-based lamination process — a cleaner bonding method with no off-gassing during manufacture.

Eco-PUL is 73% polyester and 27% polyurethane, manufactured in the USA. It meets CPSIA requirements for lead and phthalates. (CPSIA doesn’t cover food-contact safety — see below for that.)

Certified Food Safe

Our Eco-PUL has been independently tested by Celabor (Belgium), an accredited (BELAC/ISO 17025) laboratory, for food-contact safety — covering repeated contact with meat, fish, fats, fruit and vegetables. We commission this testing ourselves, in addition to any testing carried out by our fabric supplier.

View Our 60°C Washable Eco-PUL Fabric Range

Let's take a closer look...

The Patterned, Polyester Side

Microscopic View of the PUL Polyester Side with pin for scale.

Let’s look in more detail using a microscope – this photo shows the polyester side of the PUL with a pin for scale. The weave of the fabric and even the individual fibres are visible.

The Waterproof, Polyurethane Side

Microscopic View of the PUL Polyurethane Side with pin for scale.

This photo shows the polyurethane laminate side of the PUL. You can see that the polyurethane has coated the polyester. However, some holes remain – these are large enough allow the fabric to ‘breathe’, but too small for water to pass through.

The 'Droplet Test'

Microscopic View of PUL Polyurethane Side with droplet of water and pin for scale.

This photo shows a droplet of water on the polyurethane side of the fabric. You can see that the droplet sits on the surface and does not soak in. This demonstrates the waterproof aspect of the PUL.

Combined with the pores visible in the photo above, this is what makes Eco-PUL microporous rather than hydrophilic  — it breathes, rather than simply repelling water on the surface. 

If the polyester side comes into contact with water, it will become damp, but water will not penetrate the interior polyurethane layer.

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