When the fabric is subjected to a certain tension during the processing, a certain accumulation deformation will occur, and the wet heat performance of the fiber itself will cause the shrinkage effect of the fabric before and after the garment, which affects the size and processing quality of the garment. Therefore, before the garment processing, it should be pre-shrinked by the shrinking machine, which belongs to the category of fabric finishing.
The fabric is constantly subjected to tension during processing, and the yarn and fiber produce accumulated elongational deformation. The greater the tension, the more accumulated stress deformation. After the tension disappears, the elastic deformation in the accumulated deformation will be released, making the length of the fabric smaller and producing a natural shrinkage. In production, some fabrics usually need to be placed for a period of time before being cut, in order to give the fabric enough time for natural shrinkage.
Fibers with hydrophilic properties can cause anisotropic expansion after water absorption, which is the main reason for the water absorption shrinkage of the fabric. The better the hygroscopicity of the hydrophilic fibers, the greater the shrinkage of the woven fabric. The design idea of the damp heat shrinking machine is to take advantage of the water-absorbing shrinkage of the fabric, and the pre-shrinking process adopted is “spray drying”.
Synthetic fiber undergoes heat shrinkage during processing and use. The main reason is that when the temperature of the fiber exceeds the glass transition temperature, the orientation structure and crystal structure of the internal supramolecular change. Macroscopically, the fiber length shrinks and directly reacts. On the fabric is the change in fabric length and width. When ironing synthetic fabrics such as polyester, the temperature is strictly controlled to avoid heat shrinkage.www.haida-textile.com