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Rayon:
advantage:
Viscose rayon is a medium to heavy fiber with fair to good strength and abrasion resistance. It has hydrophilic properties (11 percent moisture regain). The fiber can be dry cleaned and washed with good care. No static or pilling, and it's not expensive.
shortcoming:
Rayon will lose 30-50% of its strength in wet state, so care should be taken when washing, and the strength will recover after drying (improved viscose rayon - high wet modulus (HWM) Viscose fiber, there is no such problem), rayon has poor elasticity and rebound performance, and it will shrink greatly after washing, and it is also easy to mildew.
Polyester:
1. High strength. The short fiber strength is 2.6～5.7cN/dtex, and the high strength fiber is 5.6cN/dtex
~8.0cN/dtex. Due to its low hygroscopicity, its wet strength is essentially the same as its dry strength. The impact strength is 4 times higher than that of nylon and 20 times higher than that of viscose fiber.
2. Good elasticity. The elasticity is close to that of wool, and when it is stretched by 5% to 6%, it can be almost completely restored. The wrinkle resistance exceeds other fibers, that is, the fabric does not wrinkle and has good dimensional stability. The elastic modulus is 22-141cN/dtex, about 2-3 times higher than that of nylon.
3. Heat resistance and thermal stability are the best among synthetic fabrics.
4. The surface of polyester is smooth, and the internal molecules are tightly arranged.
5. Good abrasion resistance. Abrasion resistance is second only to nylon with the best abrasion resistance, better than other natural fibers and synthetic fibers.
6. Good light fastness. Lightfastness is second only to acrylic.
7. Preservative. Resistant to bleaches, oxidants, hydrocarbons, ketones, petroleum products and inorganic acids. Dilute alkali resistance, not afraid of mildew, but hot alkali can make it decompose.
8. The dyeability is poor, but the color fastness is good and it is not easy to fade.
Shrinkage rate:
The shrinkage rate is closely related to the composition of the fabric, and the tissue related shrinkage rate and the fiber characteristics of the clothing material, the structure of the fabric and the production and processing process. The hygroscopicity of various fibers is different, the fiber with high hygroscopicity has a large shrinkage rate; otherwise, the shrinkage rate is small. Natural fibers such as cotton, wool, silk, and linen have relatively high hygroscopicity, so the rate is also high; chemical fibers such as polyester and polypropylene are hygroscopic. The tightness and looseness of the knot structure will also affect its shrinkage. , Generally, the shrinkage rate of the tighter structure is larger.
Here are the shrinkage rates of some common fabrics for reference when purchasing materials. Cotton mercerized plain cloth: the shrinkage rate is 3.5% in the warp direction and 3.5% in the weft direction; Cotton mercerized twill fabric: the shrinkage rate is 4% in the warp direction and 3% in the weft direction; Shrinkage rate is 6% in warp direction and 2.5% in weft direction; general worsted wool: shrinkage rate is 4% in warp direction and 3.5% in weft direction; silk crepe chine: shrinkage rate is 100% in warp direction 10 per cent, 3 per cent latitude.
