Looking for a fabric that is lightweight, durable and waterproof? Polyurethane laminate is just that. Initially created to be used in hospitals, polyurethane laminate (PUL) has expanded to cloth diapers, sewers and camping gear. Also, many people who are striving to live a more eco-friendly lifestyle are seeking out reusable products, many of which are made with PUL. The fabric is flexible, can be thrown in the wash and dryer, is easy to sew and comes in a wide array of colors and styles.
PUL is used in outdoor gear, cloth diapers and diaper covers, bibs and mattress liners because it is a waterproof and durable material. It's also used to make reusable items such as wet bags, sandwich wraps and lunch bags. It withstands multiple washings and dryings.
Polyurethane laminate is thin, durable, flexible and 100 percent waterproof. To make PUL, a layer of polyurethane is laminated through heat onto a piece of fabric --- typically polyester, cotton or a poly blend --- creating a fabric-to-plastic material. PUL allows the user to appreciate a soft fabric against the skin while also providing waterproof protection.
Polyurethane laminate is measured in mil and can typically be purchased as one or two mil. A mil is a measurement that is one-thousandth of an inch. One mil PUL tends to be more breathable and flexible than two mil, which tends to be thicker and more durable. PUL can also be purchased in a few different style: classic PUL, sandwich PUL, breathable PUL, and PUL using specialty fabrics. Classic PUL is a basic one or two mil laminate with a single layer of polyester fabric applied to one side. It can be used for jackets, diaper covers and diaper accessories. Sandwich PUL consist of polyurethane sandwiched between two layers of fabric. This make for a softer material that is still waterproof. Breathable PUL is just like the classic style but is laminated with one mil of co-polyester film, which is microporous and allows for better breathability. Specialty PUL fabrics include minkee, which is a soft fabric that's comparable to velvet.
Polyurethane is a polymer --- a class of chemicals derived from petroleum. Polymers are created when small chemicals called monomers chemically react to other monomers and form a long chain of compounds. This chain is known as a polymer. The precursor monomer for polyurethane laminate is toluene 2, 4-diisocyanate, known as TDI. According to the National Institute for Occupational Safety and Health's International Chemical Safety Charts, this substance is possibly carcinogenic to humans. Prolonged inhalation exposure of the substance may cause asthma or skin sensitization. Polymers are generally stable, but some people worry that the toxic monomers can break down and become reactive. Other people see no hazards in using PUL, even on a baby.
PUL was originally developed for use in hospitals. Clinics wanted a waterproof barrier for mattresses and a fabric that could hold up through the autoclave---a sanitization process utilizing very high temperatures.