Why do some fabrics become more comfortable the more they are washed (such as bedsheets) and some fabrics get less comfortable (such as fleece)?



Why do some fabrics become more comfortable the more they are washed (such as bedsheets) and some fabrics get less comfortable (such as fleece)?

In: Physics

I don’t know about the more comfortable part, but I know why fleece gets scratchy and uncomfortable the more it’s washed. It’s because you’re not washing it properly. Fleece should be washed inside out if possible, on cold, and never ever dried on a high heat.

The problem is that the fibers in fleece fuse together and melt when it’s not washed/dried properly. That’s what makes it feel like that. If it’s washed properly it can stay nice and soft for a long time.

It took me until I was in my mid 20s to learn this because my mother never taught me to was clothes properly. Always read the washing instructions on the labels too. I hope someone else has a better answer for you.

I think it has to do with fiber conditioning. Nylon and Polyester are artificial fibers and are really “stiff” after the manufacturing process. Washing them in detergent causes to plastics in them to “degrade” and become more soft.

Natural fibers, like cotton and cashmere, come from animals. Those fibers were never intended to be washed in detergents. With every wash, the natural oils are removed and the natural fiber of the fabric becomes more stiff and course.

Someone once told me that very harsh chemicals are used in the process of fabric making. My favorite fabric is rayon as I tolerate it the best because I have a hypersensitivity to touch sensations. Rayon goes through very harsh chemical treatment and is not eco-friendly but is very soft so I don’t have a reaction to it. I can tolerate cotton also but after it is washed a few times. I was told one must always wash their clothing several times, including their bedding, before they use it the first time. To add, when I was a teenager sewing a lot in my day in the 1960’s, I learned that permanent press used to have elements of formaldehyde. They probably have taken that out by now. I think there are two key factors…

1. individual skin sensitivity to chemicals (usually resulting in rashes or itchy areas where there’s more contact to the fabric such as the neck)
2. individual sensitivity to touch receptors in the skin (May also result in itchiness but most likely a maddening need to pull the fabric away from the skin such as waist bands or groin areas)

Individual body differences in sweat areas, hairy areas, larger areas whether boney or fatty and where any of these areas brush against the fabric can contribute to either of the above sensitivities.

Edit: sorry, I missed the part of your question that was comparing to fleece. I have no idea about that part as I never wear fleece. And I’ve not heard much about it.

Edit: Just googled what fleece is and now I get it. It’s wool or other soft animal fur material. I’ve seen an allergist and I am very allergic to wool and do not wear it ever so it is a specific allergy and it is fairly common.

Every fiber reacts differently to water, abrasion, soap or detergent, and heat. Linen loves to be cleaned, handled, and used and gets softer over time. Poly, acrylic, and other artificial fibers melt and pill when they get too hot or are rubbed repeatedly. Rayon loses 40% of it’s strength while wet. There are lots of variables, but basically it’s because the fibers used to make bedsheets (cotton, linen) and the fibers used to make fleece garments (fleece is polyester by definition) hold up differently to whatever processes you’re using to get them clean.

Fwiw, choosing natural fibers will typically mean your clothing is more resilient and feels better for longer as long as you clean them properly. Also fleece can sometimes be rescued with a pin brush (like the kind you use on a dog) if it gets rough and pilled.

Edit: I should mention I have *heard* you can rescue fleece with a pin brush, I haven’t tried it myself! I’ve heard it’s a little labor intensive but possibly worth it if you’re talking about, say, an expensive Patagonia fleece.

In things like bed sheets where the material is thin and flat, once they weave it, they add a starch-like liquid called sizing. This helps keep it’s shape when you cut pattern pieces out. (Fabric stretches on the diagonal). Washing will remove some of the sizing. So after a few washes the fabric is more pliable.