What is fleece fabric?

What is fleece?

Fleece fabric is a soft, knitted material — most commonly polyester — that has been brushed or napped to create a lofted, insulating surface. It is designed to mimic the warmth and softness of wool but is manufactured synthetically. Fleece is lightweight, fast-drying, and holds warmth even when damp. It is widely used in outdoor jackets, athletic layers, and blankets. The word "fleece" also refers to a sheep's coat, which causes some confusion — fabric fleece and sheep fleece are different things.

What is fleece made of?

Most fleece is made from polyester, a synthetic fiber derived from petroleum. The polyester is knitted into a base fabric and then brushed on one or both sides to lift the fibers into a soft, lofted pile. Some fleece is made from recycled polyester (rPET), produced from melted-down plastic bottles — this reduces demand for virgin petroleum but the resulting fiber still sheds microplastics. A distinct category of fleece is made from natural wool, often labeled "boiled wool fleece" or "Merino fleece." Unless a garment specifically states wool, assume polyester.

Is fleece a natural fabric?

Standard fleece is synthetic, not natural. Polyester fleece is made from petroleum. Recycled polyester fleece is made from plastic. Neither is a natural fiber. Wool fleece — a separate category of product made from actual wool — is natural. The word "fleece" in the context of a jacket, pullover, or blanket almost always means polyester unless the label specifically states wool or another natural fiber.

Does fleece shed microplastics?

Yes. Polyester fleece is one of the highest sources of microplastic pollution in laundry. Studies have found that a single wash of a polyester fleece garment can release hundreds of thousands to over a million microfibers, many of which pass through wastewater treatment and enter waterways. These microplastics accumulate in aquatic ecosystems and have been found in fish, seafood, drinking water, and human tissue. Washing bags designed to capture microfibers (such as the Guppyfriend bag) reduce but do not eliminate shedding.

Is fleece warmer than wool?

Not at equivalent weights. Wool is generally warmer per unit of weight because its natural crimp creates more effective insulating air pockets and it regulates moisture better. Fleece can be warmer than lightweight wool at the same thickness because of how it traps still air in its loft. For comparable midlayer garments, merino and heavier wool outperform polyester fleece in warmth-to-weight and in breathability. Fleece has the advantage of faster drying when wet and lower cost.

What is the difference between fleece and wool?

Wool is a natural protein fiber shorn from sheep. Fleece (in most garment contexts) is a synthetic polyester fabric designed to mimic wool's insulating properties. Wool breathes, regulates temperature, resists odor, and is biodegradable. Polyester fleece sheds microplastics, does not breathe as effectively, and is derived from petroleum. Wool requires more careful washing and costs more. Fleece is machine washable and inexpensive. For outdoor use in wet conditions, some fleece products dry faster than wool; for overall environmental profile and performance, wool is the superior fiber.

What is the difference between fleece and flannel?

Flannel is a woven fabric — usually cotton or wool — that has been brushed on one side to create a soft nap. Fleece is a knitted fabric, almost always polyester, brushed to create a lofted pile. Flannel breathes and is a natural fabric when made from cotton or wool. Fleece insulates better at lightweight but does not breathe well and sheds microplastics. Flannel is common in shirts and bedding; fleece is common in outdoor layers and athletic garments.

Every brand in The Plain Thread directory uses natural fibers. Browse wool and merino brands that make warm layers without synthetic fiber.