What is the shrinkage rate and standard of hotel linen? -1

Shrinkage is a phenomenon in which hotel linen textiles change in length or width after washing, dehydrating, drying and other processes in a certain state. The degree of shrinkage involves different types of fibers, the structure of the fabric, the different external forces that the fabric is subjected to during processing, etc., and has different manifestations.

Synthetic fibers and blended fabrics are less likely to shrink, followed by wool, linen, and cotton fabrics in the middle, silk fabrics are more likely to shrink, and viscose, rayon, and artificial wool fabrics are most likely to shrink. Objectively speaking, all cotton fabrics have the problem of shrinkage and fading, and the key is the subsequent finishing. Therefore, the fabrics of general home textiles are pre-shrunk. It is worth noting that pre-shrinking treatment does not mean no shrinkage, but means that the shrinkage rate is controlled within 3%-4% of the national standard. Therefore, when purchasing hotel linen, in addition to selecting the quality, color, and pattern of the fabric, you should also understand the shrinkage rate of the fabric.

1. Reasons for fabric shrinkage

1. When the fiber is spinning, or the yarn is weaving and dyeing, the yarn fiber in the fabric is elongated or deformed by external force. At the same time, the yarn fibers and the fabric structure generate internal stress. In the static dry relaxation state, or the static wet relaxation state, or in the dynamic wet relaxation state, or the full relaxation state, the internal stress is released to different degrees to make the yarn fiber and fabric recover. to the initial state.

2. Different fibers and their fabrics have different shrinkage degrees, mainly depending on the characteristics of their fibers - the shrinkage degree of hydrophilic fibers is relatively large, such as cotton, linen, viscose and other fibers; and the shrinkage degree of hydrophobic fibers Less, such as synthetic fibers, etc.

3. When the fiber is in a wet state, it will expand due to the action of the immersion liquid, making the fiber diameter larger. For example, on the fabric, the radius of curvature of the fiber at the interweaving point of the fabric is forced to increase, resulting in shortening of the fabric length. For example, cotton fibers expand under the action of water, the cross-sectional area increases by 40-50%, and the length increases by 1-2%, while synthetic fibers shrink by heat, such as boiling water shrinkage, etc. Generally about 5 percent.

4. When the textile fiber is heated, the shape and size of the fiber change and shrink, and it cannot return to the original state after cooling down, which is called fiber heat shrinkage. The length percentage before heat shrinkage and after heat shrinkage is called heat shrinkage rate, which is generally expressed by boiling water shrinkage test, in boiling water at 100C, the percentage of fiber length shrinkage; The percentage of shrinkage is measured in the medium, and the percentage of shrinkage is also measured in steam over 100 C by steam method. The performance of fibers is different due to different conditions such as internal structure, heating temperature and time. For example, the boiling water shrinkage rate of processed polyester staple fiber is 1%, the boiling water shrinkage rate of vinylon is 5%, and the hot air shrinkage rate of polyvinyl chloride fiber is 100%. 50/50. Fibers are closely related to the dimensional stability of textile processing and fabrics, which provide some basis for the design of subsequent processes.

Second, the factors that cause the fabric to shrink

1. The raw materials of the fabric are different, and the shrinkage rate is different. Generally speaking, for fibers with high hygroscopicity, the fibers swell after soaking in water, the diameter increases, the length shortens, and the shrinkage rate is large. For example, the water absorption rate of some viscose fibers is as high as 13%, while the synthetic fiber fabric has poor hygroscopicity, and its shrinkage rate is small.

2. Yarn (thread) is formed by twisting and winding the yarn axis. Its size change in water is not only related to the nature of the fiber, but also related to its structure such as twist and compactness. Generally speaking, different fabric yarn counts have different shrinkage rates. The shrinkage rate of the fabric with a thick yarn count is large, and the shrinkage rate of the fabric with a fine yarn count is small.

3. The density of the fabric is different, and the shrinkage rate is also different. If the warp and weft densities are similar, the warp and weft shrinkage rates are also close. Fabrics with high warp density will shrink more in the warp direction, and conversely, fabrics with a higher weft density than the warp density will shrink more in the weft direction. In general, high density fabrics have better dimensional stability than low ones.

4. Different fabric production processes have different shrinkage rates. Generally speaking, during the weaving and dyeing and finishing process of the fabric, the fiber needs to be stretched many times, and the processing time is long. The shrinkage rate of the fabric with greater tension is greater, and vice versa. In order to control the width of the fabric, in the actual process, we generally use pre-shrinking to solve this problem (the post-arrangement of the previous article).

5. Washing care, including washing, drying, and ironing, each of these three steps will affect the shrinkage of the fabric. For example, the dimensional stability of hand washing is better than that of machine washing, and the washing temperature will also affect its dimensional stability. In general, the higher the temperature, the worse the stability.

Choosing an appropriate ironing temperature according to the composition of the fabric can also improve the shrinkage of the fabric. For example, cotton and linen fabrics can be ironed at high temperatures to improve their dimensional shrinkage. But not the higher the temperature the better. For synthetic fibers, high temperature ironing will not improve its shrinkage, but will damage its performance, such as making the fabric hard and brittle.