I must admit, when I first heard about this fabric, I had no idea what it meant. Then again I am not in the cloth diaper circles, so 'PUL', for a while was an unknown to me.
I don't know if others know what 'PUL' is or not, but I thought I'd share a little information on it. The following was found on Celtic Cloths. Here how PUL fabric is described:
PUL, otherwise known as polyurethane laminated fabric, is a lot more technical than just a plastic backing on fabric. The original application is the medical field, and it is still used for this purpose. Like cloth diapers, it is used to replace disposable products with reusable. It provides the waterproof barrier needed in the medical field that can survive multiple institutional washings. The laminate can also be autoclaved, which is a very high heat steam sterilization process, to make it safe for reuse even after it comes into contact with blood or other bodily fluids.
The polyurethane laminate can be customized by the manufacturer and comes in different thicknesses. For cloth diapers, 1 mil or 2 mil is generally preferred. This allows for a good stretch, complete waterproofing, and is still comfortable enough to wear next to the skin. There are other options for waterproof fabric, but PUL is so durable and reliably waterproof it has become a favorite for cloth diapers. It has been truly kid tested!
Hope that helps some folks out there. It helped me understand what it was.