Why does fabric shrink? Shrinkage rate and standards for hotel linens
Release Time:
2018-03-08 19:55
Source:
Shrinkage is a phenomenon where textiles undergo changes in length or width after processes such as washing, dehydration, and drying under certain conditions. The degree of shrinkage varies depending on different types of fibers, fabric structures, and the different external forces applied during fabric processing, showing different manifestations.
The smallest shrinkage rate is found in synthetic fibers and blended fabrics, followed by woolen fabrics, linen fabrics, and cotton fabrics in the middle, with silk fabrics shrinking more, and the largest shrinkage occurring in viscose fibers, rayon, and artificial wool fabrics. Objectively speaking, pure cotton fabrics generally have issues with shrinkage and fading, with the key being the finishing process afterward. Therefore, most home textile fabrics undergo pre-shrinking treatment. It is important to note that pre-shrinking treatment does not mean no shrinkage, but that the shrinkage rate is controlled within the national standard of 3%-4%. Thus, when selecting hotel linens, besides choosing fabric quality, color, and patterns, understanding the fabric's shrinkage rate is also necessary.
1. Causes of Fabric Shrinkage Phenomenon
1. During spinning of fibers or weaving and finishing of yarns, the yarn fibers in the fabric are stretched or deformed by external forces. At the same time, internal stresses are generated in the yarn fibers and fabric structure. Under static dry relaxation, static wet relaxation, dynamic wet relaxation, or full relaxation states, the release of internal stresses to varying degrees causes the yarn fibers and fabric to return to their initial state.
2. Different fibers and their fabrics have different degrees of shrinkage, mainly depending on the fiber characteristics—hydrophilic fibers have greater shrinkage, such as cotton, linen, viscose fibers; while hydrophobic fibers have less shrinkage, such as synthetic fibers.
3. When fibers are wet, swelling occurs due to the action of the liquid, causing the fiber diameter to increase. On the fabric, this forces an increase in the curvature radius of fibers at the interlacing points, leading to fabric length shortening. For example, cotton fibers swell under water, increasing cross-sectional area by 40-50% and length by 1-2%, while synthetic fibers generally shrink about 5% due to heat shrinkage, such as boiling water shrinkage.
4. Under heat conditions, textile fibers undergo changes in shape and size and shrink; after cooling, they cannot return to their initial state, called fiber heat shrinkage. The percentage of length before and after heat shrinkage is called the heat shrinkage rate, usually tested by boiling water shrinkage, representing the percentage of fiber length shrinkage in 100°C boiling water; also tested by hot air above 100°C or steam above 100°C. Fibers behave differently under various internal structures, heat temperatures, and times. For example, polyester staple fiber has a boiling water shrinkage rate of 1%, vinylon 5%, and chlorofiber 50% heat air shrinkage. Fiber shrinkage is closely related to textile processing and fabric dimensional stability, providing a basis for subsequent process design.
2. Factors Causing Fabric Shrinkage
1. Different raw materials of fabrics have different shrinkage rates. Generally, fibers with high moisture absorption swell when soaked, increasing diameter and shortening length, resulting in higher shrinkage rates. For example, some viscose fibers have a water absorption rate as high as 13%, while synthetic fiber fabrics have poor moisture absorption and thus lower shrinkage rates.
2. Yarn is made by twisting fibers around a spindle; its dimensional changes in water depend not only on fiber properties but also on structure such as twist and tightness. Generally, fabrics with coarser yarns have higher shrinkage rates, while those with finer yarns have lower shrinkage rates.
3. Different fabric densities result in different shrinkage rates. For example, if warp and weft densities are similar, their shrinkage rates are also close. Fabrics with higher warp density shrink more in the warp direction; conversely, fabrics with higher weft density shrink more in the weft direction. Generally, high-density fabrics have better dimensional stability than low-density ones.
4. Different fabric production processes result in different shrinkage rates. Generally, fabrics that undergo multiple stretching during weaving and finishing, with longer processing times and greater tension applied, have higher shrinkage rates; otherwise, lower. To control fabric width, pre-shrinking is commonly used in actual processes (as mentioned earlier in finishing).
5. Washing care, including washing, drying, and ironing, each step affects fabric shrinkage. For example, hand washing offers better dimensional stability than machine washing, and washing temperature also affects dimensional stability. Generally, the higher the temperature, the worse the stability.
Choosing an appropriate ironing temperature based on fabric composition can also improve fabric shrinkage. For example, cotton and linen fabrics can improve dimensional shrinkage through high-temperature ironing. However, higher temperature is not always better. For synthetic fibers, high-temperature ironing not only fails to improve shrinkage but may damage performance, such as making the fabric stiff and brittle.
General Fabric Shrinkage Rates
The formal term for "shrinkage rate" is "washed dimensional change rate," referring to the percentage of shrinkage of textiles after washing or soaking.
Shrinkage rate = (pre-wash dimension - post-wash dimension) / pre-wash dimension × 100%
Generally:
Cotton 4%--10%;
Cotton mercerized plain weave: shrinkage rate warp 3.5%, weft 3.5%;
Twill fabric 4%;
Cotton mercerized twill: shrinkage rate warp 4%, weft 3%;
Cotton plain fabric: shrinkage rate warp 6%, weft 2.5%;
Cotton polyester 3.5%--5.5%;
Chemical fiber 4%--8%;
Hotel Textile Shrinkage Rates
Hotel textile shrinkage rates can refer to:
GB/T 8628 Textiles — Preparation, marking and measurement of fabric samples and garments for determination of dimensional changes (GB/T 8628-2001, eqvISO3759:1994)
GB/T 8629 Textiles - Household washing and drying procedures for testing (GB/T 8629-2201, eqv ISO 6330:2000)
GB/T 8630 Textiles - Determination of dimensional changes after washing and drying (GB/T 8630-2002, ISO 5077:1984, MOD)
GB/T 22800-2009 Textiles for star-rated tourist hotels (see below) 4.3.1 Intrinsic quality.
Also IWS TM31, BS 4923, EN25077/26330, JIS L1909, etc. There are also individual textile standards, such as GB/T 22864-2009 "Towels", GB/T 22797-2009 "Bed Sheets", etc., which can be used as references. (Excerpt from "China Laundry" Journal, 2017 Issue 6)
Related Documents
undefined
Other News
2025.03.31
2025.03.19
2025.03.11
2025.03.10
2025.02.18
2025.02.18
Contact Information:
Hotline:
Address:
No. 46, Dongsi West Street, Dongcheng District, Beijing
Email:
China Laundry Information Center
Scan to Follow
China Business Laundry Committee
Scan to Follow
Laundry Encyclopedia
Scan to Follow
National Laundry Label Committee
Scan to Follow
China Business Vocational Appraisal
Scan to Follow
"China Laundry"
Scan to Follow
China Laundry Committee
Scan to Follow
China Business Laundry Committee
Copyright: China Commercial Federation Laundry Professional Committee
Beijing Public Network Security 11010102005379
Website Construction:China Enterprise Power Beijing