The determination of the number of core spun yarns compared with the blended yarn:

Core spun yarn

The yarn number of core spun yarn shall be determined according to its product use. The core spun yarn for shirts skirts is usually made of single yarn, so the yarn count should be controlled at a low level. For example, 11.8tex (50s) is used to make strong underwear, 18.45tex (32S) is used to make strong socks, 36.9l-28.12rex (16-21s) is used to make elastic corduroy, 73.82-49.21tex (8-12s) is used to make elastic labor card, 15.54-10.74tex (38-55s) is used to make ragged fabrics, one strand of composite yarn is used to make sewing thread core spun yarn The core spun yarn is usually medium high count, such as 13.12tex (45s), 11.14tex (53s), etc.

Determination of blending ratio:

After the number of core spun yarn is selected, the blending ratio can be calculated according to the formula.

For example, for the production of 11.8tex (50s) polyester cotton core spun yarn, the actual blending ratio of the yarn is: Polyester accounts for 49.36%, cotton accounts for 50.64%; the calculation data is very close to the actual production.

However, when designing the core spun yarn blending ratio, the proportion of cotton should be larger. First, the wearing comfort of the fabric, second, it can increase the three-dimensional sense of the pattern after the burnout of the fabric, such as 23.62tex (25s) cotton / polyester blending ratio: 66.67/33.33; 11.14tex (53s) cotton / polyester blending ratio: 52.35/47.65, etc. The spandex filament in elastic core spun yarn generally uses 15% - 20% blending ratio, which can meet the requirement of 35% elastic elongation of weft high elastic fabric, also can improve the strength of core spun yarn.

Determination of twist coefficient of core spun yarn:

The strength of core spun yarn decreases with the increase of twist factor, because the strength of filament decreases with the increase of twist factor. When the cotton content is less than 50%, although the strength of the wrapped staple fiber increases with the increase of the twist coefficient when it is within the critical twist coefficient, the former plays a major role, so the twist coefficient of the core spun yarn should be controlled on the low side. However, the twist coefficient of T / C core spun yarn used for rotten fabrics should be too small, which is generally controlled at about 304-333, so as to avoid the discomfort of some of the broken filaments. The twist coefficient of spandex core spun yarn is 20-30 higher than that of ring spun pure cotton yarn of the same variety (warp weft) count (number), which makes the yarn strength of the two yarns close.