What is acrylic fabric? The 85 percent acrylonitrile rule, Orlon's history and modacrylic

Acrylic fabric is a synthetic fiber made from a polymer that is at least 85 percent acrylonitrile by weight. That is the federal definition, and it is the line between acrylic and its cousin modacrylic. In stores it shows up as the wool-like fiber in budget sweaters, hats, socks and fake fur, and it has a longer history than most shoppers realize.

The legal definition

The Federal Trade Commission's rules at 16 CFR 303.7, read on the electronic Code of Federal Regulations as of October 20, 2026, define acrylic as "a manufactured fiber in which the fiber-forming substance is any long chain synthetic polymer composed of at least 85 percent by weight of acrylonitrile units." A fiber with less than 85 percent but at least 35 percent acrylonitrile, with exceptions, is modacrylic.

So a label that says acrylic is making a precise chemical claim. Wikipedia's entry on acrylic fiber confirms that for a fiber to be called acrylic in the U.S., the polymer must contain at least 85 percent acrylonitrile monomer, and that modacrylic often contains vinylidene chloride or vinyl bromide, which gives it flame-retardant properties.

Where it came from

Acrylic is a child of the nylon era. The Hagley Museum and Library, which holds DuPont's textile collections, says Orlon was one of the synthetic fibers that came out of DuPont's research labs following the discovery of nylon in the 1930s. At the Buffalo, New York plant in 1941, scientists in the Pioneering Research Section began exploring a material called "Fiber A." Because it was moth and mildew proof, it was first tested in marquisette window curtains, then in clothing.

Hagley says Fiber A was officially renamed and trademarked Orlon in August 1948. Its collections include a commemorative sample of Orlon acrylic fiber made in Camden, South Carolina, in 1950, and an experimental Orlon dress shirt from March 1949. Hagley also reports DuPont's claim that the world's first wash and wear suit was made of 200 and 400 denier Orlon textile yarn. Wikipedia adds that acrylic was developed in the mid-1940s but not produced in large quantities until the 1950s.

What it is good and bad at

Wikipedia describes acrylic as lightweight, soft and warm with a wool-like feel. It takes color well, is washable and is generally hypoallergenic. It is resilient compared with other synthetics and natural fibers, and because it is synthetic, the larvae of clothes moths cannot digest it. Those properties are why Hagley's story began with a fiber valued for being moth and mildew proof.

The tradeoffs are real. Wikipedia says some acrylic fabrics fuzz or pill easily, though low-pilling variants exist. If your sweater is pilling, our guide to what causes pilling and how to remove it applies directly. The same entry notes that some acrylic is used in clothing as a less expensive alternative to cashmere because the feel is similar; for the real thing, see our guide to cashmere.

Who makes it now

An odd fact: acrylic is a U.S. invention that is no longer made in bulk in the U.S. Wikipedia says production of acrylic fibers is centered in the Far East, Turkey, India, Mexico and South America, with a few European producers continuing. U.S. producers have ended production except for specialty uses, though acrylic tow and staple are still spun into yarns in the U.S. Former U.S. brands including Acrilan and Creslan are gone, while Dralon and Drytex remain in use.

DuPont's own Orlon is part of that history. Hagley's pages describe the fiber's development and early commercial uses but do not describe present-day production, so we do not claim any current status for the brand.

Modacrylic and faux fur

Wikipedia lists end uses of modacrylic as faux fur, wigs, hair extensions and protective clothing, helped by flame-retardant properties. If a faux fur coat says modacrylic on the tag, the federal definition above is what that word means, a fiber between 35 and 85 percent acrylonitrile.

How it is made

Wikipedia says the polymer is formed by free-radical polymerization in aqueous suspension, then dissolved in a solvent such as N,N-dimethylformamide or aqueous sodium thiocyanate and pushed through a multi-hole spinneret. The filaments are coagulated in a bath (wet spinning) or dried in a stream of heated inert gas (dry spinning), then washed, stretched, dried and crimped. The tow is cut into short staple lengths, like wool hairs, and spun into yarn. That is why acrylic yarn can mimic wool, and why it can also be spun on short staple equipment to resemble cotton.

Beyond clothing, the same entry lists rugs, awnings, boat covers and upholstery, and notes the fiber is used as a precursor for carbon fiber. It also credits the British firm Courtaulds with developing the Courtelle process in the late 1950s, with methyl acrylate at 6 percent and acrylonitrile polymerized in a sodium thiocyanate solution.

Hype check

Two claims to watch for are "affordable cashmere" and "vegan wool." The first is a feel claim: Wikipedia confirms the similarity of feel but nothing in the sources says it performs like cashmere. The second is accurate in the narrow sense that it contains no animal fiber, but acrylic is a petroleum-derived synthetic made by dissolving a polymer in solvents such as dimethylformamide before spinning, per Wikipedia. A "vegan" tag tells you nothing about environmental impact.

Our take

Acrylic is a perfectly honest fabric when it is sold as what it is: a warm, washable, moth-proof, inexpensive knit fiber with a tendency to pill. Skip it for anything you want to last for decades, check the tag for the percentage, and be wary of copy that borrows cashmere's or wool's reputation. If the label says acrylic, you now know the law says at least 85 percent acrylonitrile.