What Is Neoprene?

How is neoprene made?

Neoprene is made by polymerising chloroprene (2-chlorobutadiene), a colourless, toxic and flammable liquid, into a rubber. According to Britannica, the chloroprene is emulsified in water and then polymerised with free-radical initiators. Older production made chloroprene from acetylene using cuprous chloride; modern production chlorinates butadiene or isoprene.

For clothing and wetsuits, the rubber is made as a microcellular foam: tiny sealed cells that trap an inert gas, typically nitrogen. A 2025 study of diving-suit materials notes that neoprene sheets are typically laminated with knitted fabrics as a lining, so neoprene cloth is usually foam with a knitted face on one or both sides; the study’s samples include one-sided, both-sided and unlined sheets.

Where neoprene came from

Arnold Collins, a chemist in Wallace Hume Carothers’s research group at DuPont, first prepared polychloroprene in 1930 while studying by-products of divinylacetylene. Neoprene was DuPont’s trademark for it, and Britannica notes that the trademark has since become a generic name.

What are the properties of neoprene?

Neoprene is a strong, resilient rubber that resists oil, flame, oxygen and ozone, and in foam form it insulates because of the gas held in its closed cells. Britannica lists high tensile strength, resilience and resistance to swelling in hydrocarbon oils among its traits, and notes that its high cost limits it to special applications; its principal uses include wire and cable insulation, hoses, belts, gaskets and adhesives.

• Insulation: the trapped gas in the foam slows heat loss. The closed-cell structure also stops water entering the foam itself.
• Loss under pressure: squeezing the foam makes it thinner and raises its thermal conductivity. In the 2025 study, samples compressed to the pressure at about 20 m depth lost on average 64.3% of their thickness, and their estimated thermal resistance fell by 40.9%. Even at about 5 m, the study’s abstract estimates a 21.5% loss of thermal resistance.

Designers have also used neoprene in fashion collections. The V&A holds a Balenciaga mini dress from the autumn/winter 2004 collection made of printed, rubberised neoprene with knitted wool inserts.

How is neoprene measured?

Neoprene is described by the thickness of the foam sheet in millimetres, not by a fibre grade such as microns or staple length. The 2025 diving-suit study tested sheets with nominal thicknesses of 3 mm, 5 mm and 7 mm, and found that real thickness can be slightly higher than the stated figure.

Thickness matters because insulation depends on it, and pressure takes it away. The same study cites earlier work in which 8 mm neoprene lost about 52% of its thermal insulance between the surface and 39 m.

How does neoprene appear on a clothing label?

Under US rules, a neoprene garment’s fibre-content line covers its textile parts, and the foam itself need not be listed. The Federal Trade Commission’s labelling guidance makes three points that apply:

• Non-fibrous parts need no disclosure. The FTC says parts made of non-fibrous materials, giving examples such as plastic, metal and leather, do not have to be listed in the fibre content. It lists “poly-foam and foam rubber” among products the labelling rules do not cover.
• Textile faces are named by their generic names. The knitted faces laminated to the foam are textile, so their fibres are disclosed by generic name, for example nylon, polyester or spandex (see Lycra).
• Linings for warmth must still be disclosed. Where the outer part of a product is a non-textile material such as rubber, vinyl or leather, a textile lining added for warmth must be disclosed as a separate section of the label.

US textile labels must also show the country of origin and the identity of the manufacturer or dealer, which can be a company name or a Registered Identification Number (RN). A manufactured fibre made of polychloroprene, or of a chloroprene copolymer with at least 35% chloroprene units by weight, would take the generic name “rubber” under US regulation 16 CFR 303.7, not “neoprene”.

How do you tell good neoprene from poor neoprene?

Good neoprene shows a clear foam core, matches its stated thickness, still flexes freely and carries a complete label. Four checks:

1. Look at a cut edge. Turn the garment inside out and look at the seam allowance or a raw edge. Laminated neoprene shows a foam layer, with a knitted face on one or both sides. If you see no foam at all, the cloth is not neoprene sheet, whatever the description says.
2. Measure the thickness. Pinch the edge and compare it with any stated millimetre figure. In water, insulation depends on that thickness, so a thinner sheet keeps you less warm.
3. Bend a fold. On second-hand wetsuits and swimwear, flex the material between your fingers. Divers Alert Network notes that salt water reduces neoprene’s flexibility over time, so stiff, unresponsive rubber points to a worn piece.
4. Read the label. Expect the fibre content to name the faces, such as nylon or polyester, plus country of origin and an RN or company name. A lining added for warmth should have its own line.

Red flag: a label that calls the fibre content “100% neoprene” tells you little about the faces you actually touch. Ask what the knitted faces are made of.

How do you care for neoprene?

Rinse neoprene after contact with salt water, dry it on a thick hanger and store it in a ventilated place out of direct sunlight. Divers Alert Network’s guidance for diving gear sets out these steps:

• Rinse all neoprene items after every dive unless you dive only in fresh water.
• Clean and disinfect wetsuits, boots and gloves periodically with a prolonged soak, using only products designed for diving gear.
• Undo hook-and-loop fastenings and open zips before soaking, then massage the item gently under water and rinse thoroughly.
• Hang wetsuits on thick hangers to dry, with the zips open.
• Store away from direct sunlight and away from places where a petrol engine runs.

For fashion garments, follow the care label first: the knitted faces, prints and trims may set limits that the rubber alone would not.

Is neoprene sustainable?

Neoprene raises real environmental and health questions, centred on chloroprene, the toxic chemical it is made from. In 2010 the US Environmental Protection Agency classified chloroprene as a likely human carcinogen.

The EPA has focused on the neoprene plant at LaPlace, Louisiana, formerly DuPont’s Pontchartrain Works, through which DuPont was the leading neoprene producer in North America. Denka Performance Elastomer took the plant over in 2015. EPA’s 2011 National Air Toxics Assessment estimated higher than expected levels of chloroprene in the LaPlace community, which led EPA to work with the operators to assess conditions near the plant. For anyone weighing a neoprene piece against sustainable fashion goals, the questions to ask a maker are where the rubber was produced and what the faces are made of.