How duct tape is made

Duct tape is a layered sandwich of plastic film, loose cloth mesh and rubbery glue, and it was first made to seal ammo boxes.

stations: 6
things upstream: 41
raw sources: 12
steps from the ground: 9

The short version

Tape making begins with the glue. Blocks of natural rubber and plastic resin pellets are mixed in a Banbury mixer to the consistency of pizza dough, then heated in a sigma kneader. Film and cotton mesh feed into a coating unit that pushes adhesive through the cloth and onto the film. The wide roll is slit and rewound.

Mix rubber and resin

Large blocks of natural rubber break down with pellets of plastic resin in a Banbury mixer. Spiral blades work the mass to the feel of pizza dough, and the resin adds tack that rubber lacks.

Goes in
Natural rubber latex Plastic
Heat in a kneader

A sigma kneader warms the rubber and resin and processes it further. This adhesive is usually the most expensive layer in the tape.
Feed film and mesh

A polyethylene film and a cotton mesh run in together. The mesh gives strength and lets you tear by hand. Better tapes have more strands per inch.

Goes in
Polyethylene Cotton fabric
Coat through the cloth

The coating unit presses a generous layer of adhesive through the cloth onto the film, bonding the three layers. Lamination under heavy pressure is the most common method.

Goes in
Adhesive
Or co-extrude it

Some makers meld polyethylene, cloth and adhesive in one hot process. The tape is thinner and stronger, lies flatter and shows a dimpled surface. Shurtape is one of two US makers using it.
Slit and rewind

The large roll is unwrapped, sliced to width and rerolled on cardboard cores before packing and shipping.

Goes in
Cardboard

End of the lineDuct tape

Worth repeating

During World War II, Revolite, a division of Johnson & Johnson, developed a tape from rubber-based adhesive on duck cloth that resisted water and sealed ammunition cases.
The Oxford English Dictionary records duck tape in use since 1899 and duct tape since 1965.
Duct tape is often confused with gaffer tape, which is designed to be non-reflective and to come off cleanly.