The so-called reasonable shrinkage, for new cloth, refers to the standard determined according to shrinkage test results must reflect the production level of gek. For old cloth, it refers to the shrinkage test results of finished products within the allowable deviation range of customer standards. There are many factors affecting shrinkage, such as raw materials, knitting process, dyeing and washing process, setting process, mercerizing process, scratch / grinding / brushing process and operation of each process.
For the shaping, shrinkage is controlled mainly by resin or pre-determined.
For cotton cloth, the resin method is generally used to control shrinkage. When the resin can react fully, the larger the resin dosage, the better the shrinkage, but the more the strength decreases. Therefore, the amount of resin is limited.
For fabrics with drawframe and chemical fiber, the shrinkage is controlled by the predetermined method, and resin passing method is used to assist when necessary.
The function of this kind of cloth is equivalent to that of cotton fabric passing resin step by step, which determines the quality of finished products to a great extent. Its importance is self-evident and should be paid attention to. The shrinkage is also related to the door width and gram weight. In a certain range, the wider the door width, the larger the weft shrinkage, the smaller the vice versa, the heavier the weight of the gram, the smaller the warp shrinkage, and the larger the reverse, so to a certain extent, the shrinkage can be improved by adjusting the over feeding and door width. The warp and weft shrinkage of fabrics are also related. In ideal case, the sum of the warp and weft shrinkage of a fabric in a certain state is the fixed value. So, as long as no external tension is added, when the shrinkage of one direction becomes smaller, the shrinkage in the other direction will be larger. This is the guiding ideology of making shrinkage average. Of course, in the actual production process, it is impossible to do without external tension on the fabric. Therefore, measures should be taken to improve in advance. Such as back wash water, resin, etc. What measures should be taken should be taken properly, and a certain production experience should be accumulated to make accurate judgment.
