How nitrile gloves are made

Nitrile gloves are made by dipping hand-shaped ceramic formers into liquid synthetic rubber.

stations: 8
things upstream: 57
raw sources: 17
steps from the ground: 10

The short version

A clean hand-shaped mold is preheated to about 58 °C, dipped in calcium nitrate, dried and dipped into compounded nitrile emulsion, where a gelled glove forms. A bead is rolled at the cuff, and water soaks out soluble materials. Ovens dry it, then higher heat lets sulfur crosslink the rubber. It is stripped and treated with chlorinated water to reduce tack.

Clean and preheat molds

Hand-shaped molds are washed clean and warmed to about 55 to 60 °C for the first dip.

55-60 °C

Goes in
Water
Dip in coagulant

The mold dips into a water solution of calcium nitrate. It dries and reheats to about 70 °C, leaving a coating that will make the rubber gel on contact.
Dip in nitrile emulsion

Next comes a bath of compounded nitrile emulsion, where a gelled glove forms on the mold. Faster entry and exit give a more even thickness from fingertip to cuff.

Goes in
Synthetic rubber Sulfur
Bead the cuff

A bead is rolled at the top of the cuff while the film is still gel.
Soak out solubles

The mold and gel soak in water that removes water-soluble material.

Goes in
Water
Dry and cure

Ovens dry the gel at about 80 °C to just below 100 °C. A higher temperature then starts the sulfur reaction that crosslinks the polymer.
Strip and treat

The glove comes off the mold, and its surfaces are treated with chlorinated water to reduce tack.

Goes in
Chlorine
Dry and pack

The gloves are dried and readied for packaging.

Goes in
Cardboard box

End of the lineNitrile glove

Worth repeating

Medical gloves are made from latex, nitrile rubber, polyvinyl chloride and neoprene, either powdered with corn starch or unpowdered.
William Halsted asked the Goodyear Rubber Company for thin rubber gloves for his future wife, Caroline Hampton, after she developed a skin reaction in 1889 or 1890, and he introduced sterilized gloves at Johns Hopkins in 1894.