What is the difference between knitting yarn and weaving yarn?
The difference between knitting yarn and woven yarn. Knitting yarn requires higher evenness, good softness, certain strength, extensibility and twist. In the process of forming knitted fabric on the knitting machine, the yarn is subject to complex mechanical effect. Such as stretching, bending, torsion, friction, etc.
In order to ensure normal production and product quality, knitting yarn should meet the following requirements:
1. Yarn should have certain strength and extensibility
The strength of yarn is an important quality indicator of knitting yarn.
Since the yarn is subjected to a certain amount of tension and repeated loads during the preparation and weaving process, the yarn used for knitting must have a certain strength.
In addition, the yarn is also subject to bending and torsional deformation during the knitting process, so the knitting yarn is also required to have a certain degree of extensibility to facilitate bending into loops during the knitting process and reduce yarn breakage.
2. The yarn should have good softness
The softness of knitting yarn is higher than that of weaving yarn.
Because the soft yarn is easy to bend and twist, it can make the loop structure in the knitted fabric uniform and clear and beautiful in appearance. It can also reduce yarn breakage and damage to the knitting machine parts during the weaving process.
3. The yarn should have a certain twist
Generally speaking, knitting yarns have a lower twist than weaving yarns.
If the twist is too large, the softness of the yarn will be poor, and it will be difficult to bend and twist during weaving. It will also easily develop kinks, causing weaving defects and causing damage to the knitting needles;
In addition, excessively twisted yarn will affect the elasticity of the knitted fabric and cause the loops to skew.
However, the twist of the knitting yarn cannot be too low, otherwise it will affect its strength, increase breakage during weaving, and make the yarn bulky, making the fabric prone to pilling and reducing the wearing performance of the knitted fabric.
Therefore, the correct selection of twist is an important way to rationally select yarn.
The uses of knitted fabrics are different, and the twist requirements are also different.
(1) Jersey cloth requires smoothness, tightness, smooth surface and clear texture. The twist of the yarn should be larger, which can be close to the same linear density woven warp standard.
(2) The twist of the yarn used for outerwear should be larger to enhance the stiffness and improve the pilling phenomenon.
(3) Cotton wool fabrics and elastic fabrics are required to feel soft and elastic, and the twist of the yarn should be slightly lower. Generally, the lower deviation of the twist of the weft yarn for weaving with the same linear density is used.
The yarn used for fleece knitted fabrics is to facilitate brushing and make the pile thickness uniform, and the twist requirement is smaller.
In addition, the degree of twist also varies with the linear density of the yarn.
4. The linear density of the yarn should be uniform and the yarn defects should be few
The uniformity of yarn linear density, that is, the uniformity of yarn lines, is an important quality indicator of knitting yarn.
A yarn with even dryness is beneficial to knitting processing and ensures fabric quality, making the loop structure uniform and the cloth surface clear.
Yarn defects are also an important indicator of yarn used in card clothing.
If there are thick spots on the yarn, the knitting cannot pass smoothly, causing yarn breakage or damage to machine parts, and it is easy to form “horizontal stripes” and “cloud spots” on the cloth surface, reducing the quality of knitted fabrics;
If there are details on the yarn, the strength is insufficient and the ends are easily broken, affecting the quality of the fabric and reducing the productivity of the machine.
Because there are multiple loop-forming systems on the knitting machine that feed yarn into loops at the same time, not only is the yarn thickness of each loop required to be uniform, but the difference in yarn thickness between each loop must also be strictly controlled, otherwise it will form on the cloth. Defects such as horizontal stripes and shadows reduce fabric quality.
5. Yarn should have good hygroscopicity
The ability of yarn to absorb moisture from the air is called hygroscopicity.
The moisture absorption capabilities of various fibers vary greatly, and the amount of moisture absorption varies with the temperature and humidity of the air.
Yarns used in knitting production should have certain hygroscopicity.
Under the same relative humidity conditions, yarn with good hygroscopicity, in addition to its better electrical conductivity, is also beneficial to the stability of yarn twisting.And the elongation is improved, so that the yarn has good weaving performance.
6. The yarn should have good smoothness and small friction coefficient
Knitting yarn should be as free from impurities and oil stains as possible, and should be very smooth.
Unsmooth yarns cause severe wear and tear on machine parts and are easy to damage machine parts. There are also many flying flowers in the workshop, which not only affects the health of workers, but also affects the productivity of knitting machines and the quality of fabrics.