The most common 10 kinds of textile fabrics shrinkage and influencing factors

The shrinkage of a fabric refers to the percentage of shrinkage of the fabric after the fabric is washed or soaked. Shrinkage is a phenomenon in which the length or width of the textile changes after washing, dehydration, drying and the like in a certain state. The degree of shrinkage involves different kinds of fibers, the structure of the fabric, the different external forces to which the fabric is subjected, and so on.
Shrinkage is the smallest of synthetic fibers and blended fabrics, followed by wool, linen, cotton center, silk shrunk larger, but the largest is viscose, rayon, artificial wool fabric. Objectively speaking, the number of cotton fabrics there are shrinking fade problem, the key is the rear of finishing. So the general textile fabrics are pre-shrink processing. It is noteworthy that after the pre-shrinking does not mean that does not shrink, but refers to the shrinkage control in the national standard of 3% -4% of clothing materials, especially natural fibers will shrink. Therefore, in the purchase of clothing, in addition to fabric quality, color, pattern selection, the fabric shrinkage should also be understood.
First, the impact of fiber and shrinkage
The fiber itself, after absorbing water, will have a certain degree of swelling. Usually fiber swelling are anisotropic (except nylon), that is, shorter length, diameter increases. Usually before and after the fabric into the water the difference between the length of the original length as the shrinkage rate. The stronger the water absorption capacity, the more severe swelling, the higher the shrinkage, the worse the dimensional stability of the fabric.
The length of the fabric itself is different from the length of yarn (yarn) used, and the difference between the two is usually expressed in terms of weaving shrinkage.
Shrinkage (%) = [yarn (yarn) length - fabric length] / fabric length
After the fabric is drained, due to the swelling of the fiber itself, the length of the fabric is further shortened, resulting in shrinkage. Weaving shrinkage rate of different, the size of its shrinkage is different. The structure of the fabric itself and the weaving tension, the weaving rate is different. Small weaving tension, dense fabric, weaving shrinkage rate, the shrinkage of the fabric is small; weaving tension, the fabric is loose and light, weaving shrinkage rate, the shrinkage of the fabric is large. In the dyeing and finishing process, in order to reduce the shrinkage of the fabric, often using pre-shrinking finishing approach to increase the density, weaving advance rate, thereby reducing the shrinkage of the fabric.
Second, the causes of shrinkage:
(1) When the fiber is spinning or when the yarn is weaving and dyeing and finishing, the yarn fiber in the fabric is stretched or deformed by the external force, meanwhile, the internal stress occurs in the yarn fiber and the fabric structure, and in the state of static dry relaxation , Or static wet or loose state, or in the state of dynamic wet relaxation, the state of full relaxation, the release of varying degrees of internal stress, so that the yarn fibers and fabrics back to its original state.
(2) Different fibers and their fabrics, which shrink to varying degrees, depend mainly on the characteristics of their fibers - hydrophilic fibers shrink to a greater degree, such as cotton, hemp, viscose and other fibers; and shrinkage of hydrophobic fibers To a lesser degree, such as synthetic fibers.
(3) When the fiber is in wet state, the fiber diameter becomes larger due to bulking caused by the immersion liquid. For example, on the fabric, the radius of curvature of the fiber forcing the interlacing point of the fabric increases, resulting in shortening of the fabric length. For example, cotton fibers are expanded under the action of water, the cross-sectional area is increased by 40-50% and the length is increased by 1-2%, while the synthetic fibers are heat-shrinkable, such as boiling water shrinkage, generally about 5%.
(4) under the condition of heated textile fiber, the shape and size of the fiber change and shrink, after cooling down, it can not return to the initial state, called the fiber thermal contraction. The percentage of the length before and after heat shrinkage is called the heat shrinkage, which is generally expressed as the percentage of shrinkage of the fiber length in boiling water at 100 ° C, as measured by boiling water shrinkage. Hot air Measured in the percentage of contraction, but also by steam, in more than 100 ℃ vapor measured its percentage of contraction. For example, the shrinkage of boiling water of processed polyester staple fiber is 1%, the shrinkage rate of vinylon boiling water is 5%, and the shrinkage rate of hot air of vinylon fiber is 50%. Fiber in the textile processing and the dimensional stability of the fabric is closely related to the design for the post-process to provide some basis.
Third, the general fabric shrinkage is
Cotton 4% - 10%;
Chemical fiber 4% - 8%;
Cotton polyester 3.5% - 5 5%;
Natural white cloth is 3%;
Blue cloth is 3-4%;
Poplin is 3-4.5%;
Flower fabric is 3-3.5%;
Twill 4%;
Labor cloth is 10%;
Cotton is 10%.
Fourth, the impact of shrinkage reasons
1, raw materials
Different raw materials, shrinkage different. In general, large hygroscopic fibers, after soaking fiber expansion, increased diameter, shortened length, shrinkage is large. If any viscose fiber water absorption as high as 13%, while the synthetic fiber hygroscopicity is poor, the shrinkage is small.
2, density
Fabric density, shrinkage is also different. If the latitude and longitude density is similar, its latitude and longitude shrinkage is also close. The density of the fabric, shrinkage by the large, on the contrary, weft density is greater than the density of the fabric, weft shrinkage is large.
3, gauze thickness
Fabric yarn count different thickness, shrinkage is also different. Gauze coarse cloth shrinkage on the large yarn count fine fabric shrinkage is small.
4, the production process
Different fabric production process, shrinkage is also different. In general, the fabric in the weaving and dyeing process, the fiber to be stretched several times, processing time is long, the larger the tension of the fabric shrinkage is large, otherwise small.
5, fiber composition
Natural plant fibers (such as cotton, hemp) and plant regenerated fibers (such as viscose) tend to hygroscopic and swell more than synthetic fibers (such as polyester and acrylic), so shrinkage is greater and wool is due to the scale structure on the fiber surface And easily felted, affecting its dimensional stability.
6, fabric structure
Under normal circumstances, the dimensional stability of woven fabric is better than knitted fabric; the dimensional stability of high-density fabric is better than low-density. In woven fabrics, the plain weave fabric shrinkage is less than flannel fabric; and knitwear, plain needle tissue shrinkage is smaller than the rib fabric.
7, production and processing
As the fabric dyeing, printing, finishing process, will inevitably be stretched by the machine, so that there is tension on the fabric. However, the fabric is easy to relieve tension when it is in contact with water, so we find the fabric shrinks after washing. In the actual process, we generally use pre-shrinking to solve this problem.
8, washing care process
Wash care, including washing, drying, ironing, three steps each step will affect the shrinkage of the fabric. For example, hand-wash samples have better dimensional stability than machine-wash samples, and washing temperatures also affect their dimensional stability. In general, the higher the temperature, the worse the stability. Sample drying method on the shrinkage of the fabric is also relatively large.
Drying methods are commonly used, drip drying method, metal mesh tiling method, hanging drying method and drum drying method. The drip-drying method had the least effect on the size of the fabric, while the drum-crown method had the greatest effect on the size of the fabric, with the remaining two centered.
In addition, according to the composition of the fabric to choose a suitable ironing temperature, but also can improve the shrinkage of the fabric. For example, cotton and linen fabrics can be ironed at high temperatures to improve their dimensional reduction. But not the higher the temperature the better, for synthetic fibers, high-temperature ironing not only can not improve its shrinkage, but will be its performance has been damaged, such as fabric hair brittle crisp.
Xinxiang City Yulong Textile Co., Ltd. was established in 2002, over the years focused on the production of flame retardant, fluorescent-oriented variety of functional fabrics and security clothing. The company has afunctional fabric factory and protective clothing factory, as the domestic functional textile industry leader, Yu Long textile more groundbreaking integration of its fabric and clothing two factories of the advantages of resources, effort to build functional fabrics and clothing Station service center.