Sanforization

It works by stretching, shrinking, and fixing the woven cloth in both length and width before cutting and producing, to reduce the shrinkage which would otherwise occur after washing.

The original patent mentioned "goods of cotton, linen, woolen, silk, rayon, and combinations thereof".

The cloth to be treated is transported between rubber sleeve and heated cylinder and is forced to follow this brief compression and lateral expansion, and relaxation.

The greater the pressure applied to the rubber sleeve during sanforization, the less shrinking will occur once the garment is in use.

Karate uniforms are often of 10, 12, 14, or 16 ounces per yard (310, 370, 430, or 500 g/m) cotton so shrinkage can be quite severe after washing and drying.