Definition of Shrinkage, Sanforization
Fibre Content Determines Shrinkage. Textile producers and finishers understand shrinkage as any form of negative change in dimensions of textile products under the influence of high humidity/water/ heat. Sanforization is a process that stabilizes the fabric before it is cut by stretching and shrinking it. Named after its inventor, Sanford Lockwood Cluett, it was patented in 1930. This is done in order to reduce the amount of shrinkage that can happen after your jeans’ first wash.
The result of sanforization leads to 1-3% shrinkage, as opposed to 10% shrinkage with unsanforized (shrink to fit) denim. Basic denim finishing chemicals should provide improved fabric surface effects for Sanforizing, cutting and sewing. The finishing chemicals should not penetrate into the fabric, so no heat is required and no wetting agent is necessary. For uniformity of chemical application, a wet pick-up of at least 70% should be used.
The term sanforization is used to refer to the pre-emption of shrinkage by suitable mechanical and/or hydrothermal finishing processes. Shrinkage potential after different treatment processes for woven fabrics.
- Greige fabric, depending on fabric weight up to 10 per cent;
- Greige denim (after stretching) up to 18 per cent;
- Washed denim fabric up to 10 per cent;
- Bleached fabric approx. 5 per cent;
- Dyed fabric approx. 5 to 8 per cent; and
- Shrunk (sanforized) fabric less than +/- 1 per cent.