What is bulked yarn
Textured yarn, the production principle is the same as POY-FDY composite yarn, using high shrinkage fiber Yarn mixed with regular fibers in a certain proportion. After the yarn is wet and heat treated, the high-shrinkage fibers shrink more and form the core of the yarn, while the regular fibers shrink less.It is extruded on the surface of the yarn to form a loop shape, which is the skin layer of the yarn. This is the so-called “skin-core” structure. It can be spun purely or blended with other fibers. Textiles produced using bulked yarn are soft, fluffy and have good warmth retention properties. They are mainly used to make autumn and winter fleece sweaters, underwear, etc. .
Main performance indicators of bulked yarn
Grey fabrics made of bulked yarn are generally dyed, raised (single-sided or double-sided) and finished. The fabric is required to feel soft, fluffy, elastic and evenly dyed. Therefore, the bulking degree of bulked yarn, raw material specifications, mixing uniformity, etc. are its main performance indicators.
Bulkiness is the degree of expansion of raw yarn after moisture heat treatment. It is the main factor that determines the bulkiness, softness and elasticity of the fabric. General requirements The bulkiness of the yarn is above 22%. In actual production, the shrinkage rate of yarn is generally used as the measured index to check the bulkiness, which is generally between 18% and 19.5%. Regarding the measurement of shrinkage, the following issues should be paid attention to: ⑴ 20g of tension should be pre-added before measuring the length of the original yarn; ⑵ Steam the measured raw materials in steam for 5 minutes; ⑶ The bulked yarn after shrinkage should also be added with 20g of tension Measure the length again.
Too high a bulking degree will result in a tight, fluffy, soft, and inelastic gray fabric; too small a bulking degree will result in a loose gray fabric and poor plush feel.
The mixing uniformity of raw materials is an important factor affecting the dyeing effect. Uneven mixing will lead to uneven dyeing of the cloth and also affect the bulking performance. .
Spinning bulked yarn on cotton spinning equipment
The bulked yarns spun on cotton spinning equipment mainly include the following varieties: wool and acrylic blends; rabbit hair, wool and acrylic blends; acrylic and viscose blends; acrylic and cotton blends, pure acrylic, etc. Spinning count 40Nm~60Nm.
In Among all bulked yarn varieties, the blending ratio of high-shrinkage acrylic is generally between 35% and 45%, and the blending ratio of wool, rabbit, and wool is generally within 20%. The selection of the above specifications and blending ratio is mainly based on the processing capacity of the cotton spinning equipment and the requirements of the final product.
The characteristic of bulked yarn production is the mixed spinning of multiple raw materials. The main problem in spinning is how to achieve full mixing of multiple raw materials. In addition, wool fibers are generally over 80mm, and the longest ones are over 150mm. How to adapt them to the technological performance of cotton spinning equipment is also an important issue.
According to traditional cotton spinning technology, there are two main ways to achieve the mixing of multiple raw material components: (1)
Start mixing on a cotton pad. The final mixing effect is better, but the blending ratio of various raw material components in the final product is not accurate; (2)
Mixing on the drawing line can keep the blending ratio accurate, but it is not easy to mix evenly, and when some fibers are individually formed into strips, the production in the carding process is quite difficult due to high static electricity. It can be seen that traditional cottonIn order to spin high-quality bulked yarn on cotton spinning equipment, before the cotton blowing process Add raw material pretreatment process. The purpose of this process is to cut wool balls into wool fibers of a certain length (51mm), and preliminary mix a variety of raw materials according to the designed ratio, spray oil during the mixing process, and then mix the preliminary mixed materials. Raw materials beatAfter the moisture is balanced and regained, it is put on the cotton table for formal production.
In addition to the raw material pretreatment process, the production process of bulked yarn, other processes from blowroom to winding are all the same as the cotton spinning process The process is the same, that is, raw material pretreatment process – blowroom process – carding process – roughening process – spinning process – rolling process – into bales.
Raw material pretreatment process
hair ball→shearing machine→fan→small mixing bin→certain length of wool fiber (other fibers)→cotton curtain opening blender→fan→large mixing bin →Mix raw materials→Pack.
The transformation of the carding process mainly includes: cylinder, flat card clothing, licker-in card clothing and cotton feeding plate. The card clothing must be replaced with special card clothing or dual-purpose card clothing suitable for spinning chemical fibers, and the cotton feed plate must be replaced with a double-curved working surface type suitable for spinning medium and long fibers.
The upper and lower pins of the spinning frame should be changed to parts suitable for spinning medium-long fibers and the corresponding upper and lower rubber rings. The hardness of the rubber rollers should reach about 85 degrees.
What is the difference from solid yarn
1. Textured yarn will appear jagged after dyeing or heating. The body surface shows a swelling effect. Solid yarn will not deform after being heated or dyed.
2. The bulked yarn contains shrinkable acrylic, which shrinks when encountering heat and moisture during the dyeing or bulking process, causing the yarn surface to show a bulking effect. It is mostly used in artificial fur or wool knitted sweaters. . Solid yarn does not contain shrinkage components and is mostly used in woven fabrics.
3. Solid cotton will not shrink (i.e. will not shorten) under high temperature, while expanded cotton will shorten under high temperature. The shrinkage rate depends on the characteristics of the fiber itself. Simply put: bulked yarn will appear jagged after dyeing or heating, and the surface of the yarn will show a bulking effect. Solid yarn will not deform after being heated or dyed.
