Polyurethane laminate (PUL, thermal stretch, fuzzy rubber) is a compound fabric made by laminating a cloth fabric to one or both sides of a thin film of polyurethane. Polyurethane laminated fabrics have a wide range of applications in medical, automotive and garment uses.
Most PUL fabric is made by laminating lightweight polyester interlock knit fabric to a 1mm thick film of polyurethane. There are two processes used for lamination: solvent lamination, which fuses the fabric and polyurethane film into a single monolithic fabric, and hot melt, which uses heat-activated glue to adhere the fabrics together. Woven fabric and fleece fabric can also be used, but a stiff fabric will drastically reduce the elasticity of the finished laminate.
PU laminate cloth is waterproof, breathes and stretches somewhat, and is soft and flexible. It can usually be machine-washed and dried, and cleaned with dilute bleach or alcohol.
PU fabric is useful as a wind and/or water barrier in the construction of fluid-splash protecting garments, shower curtains, and outerwear clothing. It is used for upholstery, especially in cars and restaurants.[1]
It is used in watersports clothing and equipment.[2] PUL is used for tents and waterproofing backpacks.[3]
Because it can be readily cleaned and sterilized, PUL is used for medical bedding, mattress protectors, reusable incontinence products, diapers/nappies, wet bags, and cloth menstrual pads.[4] [5]
There are many different polyurethane blends and resin types,[6] which vary in durability, resistance to heat, ambient humidity, and light,[1] and the maximum temperature they will stand (some, for medical use, are autoclavable).[2] Resistance is measured by accelerated aging in a harsh controlled environment; the number of weeks survived is expressed as a hydrolysis resistance in units of years (expected under normal conditions).[7] Apart from heat and humidity, bleach, salt, and chlorine can also shorten coating life.[3]
If PUL is kept wet for a long time, it disintegrates into the water and sticks to itself, though it will probably go mouldy first.[7] If the polyurethane starts delaminating from the fabric, it may be possible to relaminate it with care and a hot iron. If the PU coating has decayed, it can be replaced.[8] [3]