Why does cotton shrink? Why is it normal for fabrics to shrink?

Pure cotton fabric is composed of plant fibers. When the fabric is soaked, water molecules will enter the interior of the cotton fiber, causing the fiber to swell. When the weft direction (or warp direction) of the fabric swells and becomes thicker, the fabric will produce Shrink, so the longer it is immersed in water, the smaller the shrinkage will be. Of course, this is only relative, and it will not shrink endlessly.

During the textile dyeing and finishing process of pure cotton fabrics, the fibers are stretched by a certain external force. After finishing, this stretching will temporarily be “stable” “state. When soaked in water and washed, the moisture will gradually weaken the connection between fiber molecules, reduce the friction on the fiber surface, destroy the temporary “stable” state, and the fiber will return to or approach its original equilibrium state. Generally speaking, during the weaving, dyeing and finishing process, it needs to be stretched many times. The fabric with greater tension will have a greater shrinkage, and vice versa.

Everyone should know that the yarn weaves of cotton bedding can be roughly divided into 1288*68, 130*70/13372/40 satin/60 satin/80 satin, etc. The higher the yarn weave, the higher the quality of the fabric. The processing is also different (such as pre-shrinking treatment or steam pre-shrinking, etc., to eliminate the potential of fabric shrinkage in advance, and the fabric will generally not shrink significantly after pre-shrinking treatment).

Commonly used cotton bedding can be roughly divided into four types: ordinary cotton four-piece set, combed cotton four-piece set, mercerized cotton four-piece set, and brushed four-piece set. The ordinary shrinkage rate can only be seen It’s just my luck. Generally speaking, products from good manufacturers can still be used. Sorry, combed cotton and mercerized cotton are generally processed before leaving the factory, and the problem is not big. Regarding sanding, I can only say that the cheaper it is, the greater the shrinkage. Why is the same thing cheaper in size and less post-processing? .

For pure cotton fabric products, the national standard shrinkage rate is: less than or equal to 5% (that is: 95cm of 100cm fabric is normal after washing) pure cotton After washing the bedding, you should stretch it when it is about to dry. Once the quilt cover is dry, stretching is useless. If your quilt cover is really much larger than the quilt core, shrinking it is useless. A general pure cotton quilt cover shrinks to 10cm, which is a standard 200*230 quilt cover. The shrunk size is 190*220cm.

Do not use hot water for washing. The water temperature should be controlled below 35℃. Do not soak in detergent for a long time and do not use detergent above 120℃. Iron at high temperature, do not expose to the sun, and do not tumble dry. For correct washing and drying, be sure to place it in a cool place, lay it flat or use a stick-shaped drying rack, and it is best to wash it by hand.

Objectively speaking, all cotton fabrics have the problem of shrinkage and fading. The key is post-processing. Therefore, generally home textile fabrics have been pre-shrunk. However, pre-shrinking does not It means no shrinkage, but means that the shrinkage rate is controlled within the national standard 3%-4%%.