Shrinkage (fabric)
Encyclopedia
Shrinkage is when a fabric becomes smaller than its original size, usually through the process of laundry
Laundry
Laundry is a noun that refers to the act of washing clothing and linens, the place where that washing is done, and/or that which needs to be, is being, or has been laundered...

. Novice users of modern laundry machines sometimes experience accidental shrinkage of garments, especially when applying heat. Others may intentionally try to shrink a garment in their size. Some may purchase a garment one or more sizes larger in anticipation of shrinkage.

Causes

For wool
Wool
Wool is the textile fiber obtained from sheep and certain other animals, including cashmere from goats, mohair from goats, qiviut from muskoxen, vicuña, alpaca, camel from animals in the camel family, and angora from rabbits....

garments, this is due to scales on the fibers which heat and agitation cause to stick together. Other fabrics are stretched by mechanical forces during production, and can shrink slightly when heated (though to a lesser degree than wool). Some clothes are "pre-shrunk" to avoid this problem.
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