is a family of synthetic rubber
s that are produced by polymerization of chloroprene
.Werner Obrecht, Jean-Pierre Lambert, Michael Happ, Christiane Oppenheimer-Stix, John Dunn and Ralf Krüger "Rubber, 4. Emulsion Rubbers" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley-VCH, Weinheim. Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range. Neoprene is sold either as solid rubber or in latex
form, and is used in a wide variety of applications, such as laptop
braces (wrist, knee, etc.), electrical insulation
, liquid and sheet applied elastomeric membranes or flashings, and automotive
Neoprene is produced by free-radical polymerization of chloroprene
. In commercial production, this polymer is prepared by free radical emulsion polymerization. Polymerization is initiated using potassium persulfate
. Bifunctional nucleophiles, metal oxides (e.g. zinc oxide), and thiourea
s are used to crosslink individual polymer strands.
Neoprene was invented by DuPont
scientists on April 17, 1930 after Dr Elmer K. Bolton
of DuPont attended a lecture by Fr Julius Arthur Nieuwland
, a professor of chemistry
at the University of Notre Dame
. Nieuwland's research was focused on acetylene
chemistry and during the course of his work he produced divinyl acetylene, a jelly that firms into an elastic compound similar to rubber when passed over sulfur dichloride
. After DuPont purchased the patent
rights from the university, Wallace Carothers
of DuPont took over commercial development of Nieuwland's discovery in collaboration with Nieuwland himself. Arnold Collins
at DuPont focused on monovinyl acetylene and allowed it to react with hydrogen chloride
gas, manufacturing chloroprene
.John K. Smith. The Ten-Year Invention: Neoprene and Du Pont Research, 1930–1939
. Technology and Culture 26(1):34-55 January 1985
DuPont first marketed the compound in 1931 under the trade name DuPrene, but its commercial possibilities were limited by the original manufacturing process, which left the product with a foul odor. A new process was developed, which eliminated the odor-causing byproducts and halved production costs, and the company began selling the material to manufacturers of finished end-products. To prevent shoddy manufacturers from harming the product's reputation, the trademark DuPrene was restricted to apply only to the material sold by DuPont. Since the company itself did not manufacture any DuPrene-containing end products, the trademark was dropped in 1937 and replaced with a generic name, neoprene, in an attempt "to signify that the material is an ingredient, not a finished consumer product". DuPont then worked extensively to generate demand for its product, implementing a marketing strategy that included publishing its own technical journal, which extensively publicized neoprene's uses as well as advertising other companies' neoprene-based products. By 1939, sales of neoprene were generating profits over $300,000 for the company ().
Neoprene resists degradation more than natural
or synthetic rubber
. This relative inertness makes it well suited for demanding applications such as gasket
s, and corrosion
s. It can be used as a base for adhesive
s, noise isolation in power transformer
installations, and as padding in external metal cases to protect the contents while allowing a snug fit. It resists burning better than exclusively hydrocarbon
based rubbers, resulting in its appearance in weather stripping for fire door
s and in combat related attire such as gloves and face masks. Because of its tolerance of extreme conditions, neoprene is used to line landfills. Neoprene's burn point is around 260°C (500°F). Neoprene foam is also used in many applications. Neoprene foam can be produced in either closed-cell or open-cell form. The closed-cell form is waterproof
, less compressible and more expensive. The open-cell form can be breathable
Neoprene is used as a load bearing base, usually between two prefabricated reinforced concrete elements or steel plates as well to evenly guide force from one element to another.Damon Allen. Stiffness Evaluation of Neoprene Bearing Pads under Long-Term Loads
. A Dissertation Presented to the Graduate School of The University Of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. University Of Florida 2008
Neoprene is commonly used as a material for fly fishing
waders, as it provides excellent insulation against cold. Neoprene waders are usually about 5 mm thick, and in the medium price range as compared to cheaper materials such as nylon
and rubber. However, neoprene is less expensive than breathable fabrics. A foamed neoprene containing gas cells is used as an insulation material, most notably in wetsuit
s. Foamed neoprene is also used in other insulation and shock-protection (packing) applications. In its native state, neoprene is a very pliable rubber-like material, with no better insulating properties than rubber or other solid plastics. For diving and exposure protection applications, neoprene is manufactured by foaming the plastic with nitrogen
gas, for the insulation properties of the tiny enclosed and separated gas bubbles (nitrogen is used for chemical convenience, not because it is superior to air as an insulator). The foam cells thus created also make the material quite buoyant, and the diver must compensate for this by wearing weights. Thick wet suits made at the extreme end of their cold water protection are usually made of 7 mm thick neoprene. Since foam neoprene contains gas pockets, the material compresses under water pressure, getting thinner at greater depths; a 7 mm neoprene wet suit offers much less exposure protection under 100 feet of water than at the surface. A recent advance in neoprene for wet suits is the "super-flex" variety, which mixes spandex
into the neoprene for greater flexibility.
Competitive swimming wetsuits are made of the most expanded foam; they have to be very flexible to allow the swimmer unrestricted movement. The downside is that they are quite fragile.
Recently, neoprene has become a favorite material for lifestyle and other home accessories including laptop
holders, remote control
s, mouse pad
s, and cycling chamois. In this market, it sometimes competes with LRPu
(low-resilience polyurethane), which is a sturdier (more impact-resistant) but less-used material.
The Rhodes piano
used hammer tips made of neoprene in its electric pianos, after changing from felt hammers around 1970.
Neoprene is also used for drum practice pads.
and aerated gardening systems make use of small neoprene inserts to hold plants in place while propagating cuttings or using net cups. Inserts are relatively small, ranging in size from . Neoprene is a good choice for supporting plants because of its flexibility and softness, allowing plants to be held securely in place without the chance of causing damage to the stem. Neoprene root covers also help block out light from entering the rooting chamber of hydroponic systems, allowing for better root growth and to help deter the growth of algae.
Neoprene is used for Halloween
masks and masks used for face protection, for insulating CPU socket
s, to make waterproof automotive seat covers, in liquid and sheet-applied elastomeric roof membranes or flashings, and in a neoprene- spandex
mixture for manufacture of wheelchair
positioning harnesses. Because of its chemical resistance and overall durability, neoprene is sometimes used in the manufacture of dishwashing gloves, especially as an alternative to latex
. In fashion, neoprene has been used by designers such as Gareth Pugh
, Rick Owens
and Vera Wang
. This trend, promoted by street style bloggers such as Jim Joquico of Fashion Chameleon, gained traction and trickled down to mainstream fashion around 2014.
Some people are allergic to neoprene while others can get dermatitis from thiourea
residues left from its production. The most common accelerator
in the vulcanization
of polychloroprene is ethylene thiourea
(ETU), which has been classified as reprotoxic
. The European rubber industry project called SafeRubber focused on alternatives to the use of ETU.