The sweater needs ironing after washing. Principle: Using the physical characteristics that fibers can expand and stretch in wet and hot state and keep their shape after cooling, the clothing materials are heat-set.

Water is quickly converted into steam by the heat of the iron, and vapor permeation is added into the raw material to stretch the fiber. Under the action of heat, fiber molecules move in a certain direction When the temperature drops, the fiber molecules are fixed in a new position and no longer move, and the sweater is ironed to the required appearance.

Extended data:

First, the raw materials of sweaters

Wool wool is the most popular knitted sweater, with clear stitch, smooth surface, full weight, bright color, full and elastic feel, and the sweater is more durable.

Second, the washing of sweaters.

1, when washing sweaters, use neutral detergent or neutral washing powder. It is easy to damage wool fibers by using alkaline detergent in daily laundry. The suitable washing water temperature is about 30℃. If the water temperature is too high, the woolen sweater will be felted again, and if the water temperature is too low, the washing effect will be reduced.

2. When washing, all sweaters should be carefully washed by hand except those marked "super washable" or "machine washable". Don't rub it carefully with your hands or washboard, let alone use the washing machine.

3. Otherwise, the wool fiber scales will shrink, which will greatly reduce the size of the sweater. Machine washing is easy to damage woolen sweater and make it decompose.

Baidu encyclopedia _ sweater