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Is it a barrier or a wicking fabric?

Before I answer that question, I will explain the difference between “polar” or polyester “fleece” and real fleece. Real fleece is in the knit-terry family. These are a jersey based knit in which the back side has loops instead of being smooth. The size, style and frequency of these loops; and any treatments applied to these loops after knitting; differentiates the different types of knit terry. Fleece is a fabric in which the loop side of the knit terry has been brushed to make a soft surface. That brushed side is supposed to be soft like a lamb’s fleece–hence the name. It is commonly used in sweat clothes. This fleece is absorbent, so it will absorb sweat to be slowly evaporated on the other side. While poly fleece mimics the soft effect of the brushed side of fleece, it is not knitted and treated in the same way. It also does not absorb.

A company called Polartec invented what is commonly referred to as “fleece” today. It was developed as a soft, flexible, breathable barrier fabric to use for outdoor sports and leisure activities. There are today all different looks, densities, and thicknesses of the poly “fleece”.

As a barrier fabric for diapers (the outside) it works quite well as long as the diaper doesn’t get completely saturated. Then they came up with “microfleece”. I am sure the original purpose of this fabric was for sports and outdoors like other poly fleeces. It is very stretchy and would keep an ice skater dry if he/she fell, but still allow for air circulation. Someone thought this would be a good idea in a diaper so that we could let a baby pee more in a cloth diaper and yet have the “stay dry” feel of a disposable diaper.

You may be wondering how a fabric intended to keep ice skater’s dry would allow liquid to pass through. The answer is contact. When baby pees, the pee spreads out between the microfleece and the baby’s skin. The pressure of the skin forces the urine through the microfleece, where it is absorbed by another fabric. As long as the absorbent fabric does not become saturated, there will not be enough contact force to push the urine back through to the baby’s skin. While this does keep the butt dry in one sense, it also coats the skin with a thin layer of urine with each pee.

I did use microfleece diapers with my first baby. However, because we practice EC, she never peed in them more than once. I was never really happy with them and did not use any with my second child. Since then, I want only natural fibers to touch my baby’s skin. Raw silk is a good natural substitute for wicking. Bamboo velour feels soft even when it’s wet. If you are not strict about natural fibers, that wicking sport underwear fabric actually pulls liquid through without spreading. I never recommend using microfleece, or suedecloth (which works by the same method) for a “wicking” layer. I do recommend poly fleece often for a barrier layer. Works great in the winter if a baby wears a fitted or flat or prefold diaper under fleece pants. Then the diaper cover is also the clothing–making less bulk!