Why does cotton shrink? Why is shrinkage of fabric normal?

Cotton has good hygroscopicity, high moisture retention, good heat resistance, strong alkali resistance and hygiene are the reasons why you are willing to buy cotton bed products. As for all concerned, will cotton shrink? The answer is yes. But why does cotton shrink? Do you know?
 
1: cotton material
Cotton fabrics are made up of plant fibers. When the fabric is soaked, water molecules will enter the inside of the cotton fibers and make the fibers expand. When the fabric expands in the weft (or warp) direction, & nbsp; the fabric will shrink, so the longer it is soaked in water, the larger the shrinkage is. Of course, this is only relatively speaking, No. It will be endless.  
Two: textile processing
In the dyeing and finishing process of pure cotton fabric, the fiber will be stretched by a certain external force. After finishing, the stretching will be temporary-nbsp; in-ldquo; stable-rdquo; state. In immersion washing, water will gradually weaken the relationship between the molecules of the fibers, reduce the friction force on the surface of the fibers, and make temporary & ldquo; stable & rdquo; when the state is destroyed, the fibers will restore or close to the original equilibrium state. Generally speaking, in the process of weaving and dyeing and finishing, it is necessary to stretch several times, and the shrinkage rate of the fabric with higher tension will be higher, and vice versa will be smaller.
Three: yarn weaving of fabrics
It should be known that cotton bed fabric can be divided into 1288*68, 130*70/13372/40/60/80 satin and so on. The higher the yarn is, the higher the fabric is, and the different treatment of the fabric (such as pre-shrinkage water treatment or steam pre-shrinkage, etc.) can eliminate the potential shrinkage of the fabric in advance. After pre-shrinkage treatment, the fabric will generally not be re-shrinked. There is a big shrinkage.
Four: classification of fabrics
Commonly used cotton bedding can be divided into four types: ordinary cotton four sets, combed cotton four sets, mercerized cotton four sets, and polished four sets. Ordinary shrinkage rate can only depend on personal luck. Generally speaking, good manufacturer's products can be assured. Combed cotton and mercerized cotton are usually handled when they leave the factory. It's not a big question. I can only say that the cheaper the sharpening, the bigger the shrinkage rate. Why is the same thing cheap? The size is insufficient and the post-processing procedure is reduced.
Five: shrinkage of cotton
For pure cotton fabric products, the shrinkage rate of the national standard is less than or equal to 5% (that is to say, 95 cm is normal after 100 cm cloth is washed). After washing, the bed products of pure cotton should be wiped when they are about to dry. When the quilt is dried, stretching will be useless. If your quilt cover is really much larger than the quilt heart, shrinkage is useless. The normal cotton quilt cover shrinks to 10 cm, which is a standard 200*230 quilt cover. The shrinkage size is 190*220 cm.
Six: proper washing and maintenance of cotton.
Hot water should not be used for washing. Water temperature should be controlled below 35 C. It should not be soaked in detergent for a long time, ironed at a temperature higher than 120 C. It should not be exposed to the sun or dried. Correct washing and drying should pay attention to the shade, using flat or rod-type clothes hanger, washing is best hand-washed.
Objectively speaking, there is a problem of shrinkage and fading of all cotton fabrics. The key is finishing after finishing. So the fabric of general home textiles has been pre shrinking. However, shrinkage treatment does not mean that it does not shrink, but that the shrinkage rate is controlled within the national standard 3%&mdash, 4%%.