Welcome to part 4! Where we talk about one of the most controversial component of the modern cloth diaper- PUL.
Now I want to preface this section by saying that PUL is one of the most expensive components in a cloth diaper. It is also one of the hardest materials to procure- so finding a reputable, reasonably priced PUL is a major undertaking for any diaper manufacturer.
It is also important to know that no PUL is PERFECT. After a little digging into the patent on PUL we find that it’s not even 100% waterproof. The manufacturing process creates a product that is mostly water-proof, but small amounts of liquid can still seep through or be absorbed into the polyester shell with each wash. How you treat your pul, how you wash it and how you dry it will have a significant effect on how long it lasts for you and your family.
PUL/TPU– These fabrics are made by laminating a polyurethane membrane to the back of a polyester interlock knit using either a heat or chemical process. Approximately 1.5 years or 100-200 washes. (14,17)
– (15, 16) PUL is usually adhered in a small dot pattern. (Don’t believe us- pull out a diaper out and look!) The areas between the dots are hydrophilic, which means that it absorbs water. The more water it absorbs, the faster the PUL laminate will break down. Factors such as the thickness of the polyurethane membrane and the space between the adhesion areas, all have an effect on the life of your diaper. This is why you will see that some brands/colors/prints of PUL are more prone to delamination than others.
Translation: Not all PUL is created equal. You get what you pay for.
Thermal shock can speed the process up. Polyester fabrics are strongly susceptible to thermal shock creasing caused by rapid cooling during washing. Wrinkles put into the fabric in this way are extremely difficult to remove later (if at all) , therefore a controlled lowering or cool down sequence needs to be incorporated into the wash cycle, particularly after the hot wash and during the rinsing stages. IE. Shock can increase the space between adhesions, increasing the possibility of delamination over time. So avoid extreme temperature changes.
Did you know? That certain Fungi & Bacteria eat PUL? (8)
Two organisms: Pestalotiopsis microspora E2712A and E3317B, found in the Amazon were uniquely able to breakdown PUL. Comamonas acidovorans (a bacteria strain found in many water sources across the globe) showed similar degradation. The optimum temperature for PUR esterase was 45°C. The thermostability was also determined: PUR esterase was stable within 30 min of incubation at 55°C but almost inactivated (85%) at 60°C. (12) Translation: Wash in HOT to kill bacteria
How do you prolong the life of your PUL?
Buy good quality diapers. Read reviews, paying particular attention to reports of delamination. And avoid extreme temperature changes- go from warm rinse, to hot, and then back to warm. Avoid hot to cold without a cool down period.
Note: use your common sense here- if the owner abused them and used crazy washing methods, that is not an indication of a bad diaper- just a bad diaper owner!
Join us for part 5 where we talk about washing diapers and tips on how to prolong the life of your diapers!