â–¶General knowledge about knitwear heat setting

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First, the definition of stereotypes

Stereotype is the main process of finishing. The knitted fabric passes the mechanical action of the setting machine and the anti-shrinkage, softening and hardening of the chemical agent, so that the fabric can achieve a certain shrinkage, density, hand feeling, and can achieve the appearance of uniformity of the door width, smooth lines and clear lines. .

Second, the representation of the thickness of the yarn

Indicates the thickness of the yarn, which is divided into the British count and the metric count. The commonly used inch count (Ne) indicates how many 840 yards are contained in each pound of yarn. For example, 8S/1 means that each sterling yarn contains 8 840 yards. The metric count (Nm) is the number of meters per gram of weight of yarn. By definition, the smaller the yarn count, the thicker the yarn. The unit indicating the thickness of the yarn also has a denier and a special number. The denier (D) refers to the number of grams of yarn per 9000 meters; the number (Tex) refers to the number of grams per 1000 meters of yarn. By definition, the larger the value of the denier (special number), the thicker the yarn. The British system count and the metric system count are called fixed weight units, and the number of deniers and special numbers are called fixed length units.

Third, the meaning of some knitting process parameters

1. CPI: the longitudinal density of the fabric, that is, the number of courses (modulus) within 1 inch along the longitudinal direction of the coil;

2, WPI: the transverse density of the fabric, that is, the number of stitches (number of stitches) within 1 inch of the lateral direction of the coil;

3. Gram weight: the weight of the fabric per unit area (GM/M2);

4, yarn length: generally expressed in 50C, that is, the length of 50 coils. Measured in MM.

First, the definition of stereotypes

Stereotype is the main process of finishing. The knitted fabric passes the mechanical action of the setting machine and the anti-shrinkage, softening and hardening of the chemical agent, so that the fabric can achieve a certain shrinkage, density, hand feeling, and can achieve the appearance of uniformity of the door width, smooth lines and clear lines. .

Second, the representation of the thickness of the yarn

Indicates the thickness of the yarn, which is divided into the British count and the metric count. The commonly used inch count (Ne) indicates how many 840 yards are contained in each pound of yarn. For example, 8S/1 means that each sterling yarn contains 8 840 yards. The metric count (Nm) is the number of meters per gram of weight of yarn. By definition, the smaller the yarn count, the thicker the yarn. The unit indicating the thickness of the yarn also has a denier and a special number. The denier (D) refers to the number of grams of yarn per 9000 meters; the number (Tex) refers to the number of grams per 1000 meters of yarn. By definition, the larger the value of the denier (special number), the thicker the yarn. The British system count and the metric system count are called fixed weight units, and the number of deniers and special numbers are called fixed length units.

Third, the meaning of some knitting process parameters

1. CPI: the longitudinal density of the fabric, that is, the number of courses (modulus) within 1 inch along the longitudinal direction of the coil;

2, WPI: the transverse density of the fabric, that is, the number of stitches (number of stitches) within 1 inch of the lateral direction of the coil;

3. Gram weight: the weight of the fabric per unit area (GM/M2);

4, yarn length: generally expressed in 50C, that is, the length of 50 coils. Measured in MM.

Fourth, the main physical indicators and control methods to be controlled

1. The width of the door.

The width of the door can be adjusted directly on the setting machine during production. The adjustable width of the setting machine is in centimeters, and the company's order requires that the width of the door is generally in inches. Therefore, in the production process, the inch can be adjusted after being converted into centimeters. Conversion formula: 1 inch = 2.54 cm.

2, grams weight.

Under normal circumstances, the weight is controlled by adjusting the super feed. In the case where the rest of the tension is constant, within a certain range, the larger the super-feeding, the heavier the weight, the smaller the super-feeding, and the lighter the weight.

3, the cycle.

The cycle is closely related to the weight of the gram, which refers to the repeat size of the pattern from the start point to the end point. The control method is the same as the control method of the weight. In general, the loop is controlled by adjusting the overfeed. In the case where the rest of the tension is constant, within a certain range, the larger the overfeed, the shorter the cycle, the smaller the overfeed, and the longer the cycle.

4, shrinking.

Shrinkage is one of the most important physical indicators that need to be controlled. Shrinking must be average and reasonable to be OK. For stereotypes, shrinkage is controlled primarily by resin or by a predetermined type. For pure cotton cloth, it is generally controlled by a resin method to reduce shrinkage. In the case where the resin can be sufficiently reacted, the larger the amount of the resin, the better the shrinkage, but the problem that comes with it is that the strength drops more. Therefore, the amount of the resin is limited. Under normal circumstances, B / F strength > 85 PSI, the test method is TUMBLEDRY cloth, the resin dosage is 50G / L. A formulation with a resin dosage of 50 G/L is generally considered to be a full material. For pure cotton double-faced fabrics that are only conventionally finished, the amount of resin used in 80G/L is considered to be all. The test methods are LINEDRY, HANGDRY, FLATDRY, which are generally reduced in resin production to save costs.

5, distorted

Due to the twisting of the yarn, the yarn has a certain tendency to look back after being woven into a fabric, resulting in distortion. The tendency to look back is more pronounced in fabrics with a single-sided structure. The size of the twist is related to the twist of the yarn itself, the fabric structure and the knitting process. Twisting is generally controlled by oblique or step-by-step methods, and in many cases it is controlled by a combination of the two methods. However, the type of resin, the improvement of the distortion can only adopt the oblique-type method; the resin can be used in a stepwise setting method to improve the distortion. When the amount of the resin is not too large for the sake of strength or the slanting of the fabric itself is too large to exceed the adjustable range of the setting machine, and the stepwise shaping cannot achieve the required distortion, the combination of the oblique setting and the stepwise setting may be used to improve the distortion.

6, PILLING

PILLING is related to raw material quality, fabric structure, resin reaction degree and pretreatment process. At present, there are mainly three methods for improving PILLING: one, enzymatic washing; second, passing resin; third, adding an appropriate amount of hard pulp to the materials.

7, strong

Strength is a physical indicator that cannot be repaired, so it should be carefully controlled during the production process. The strength is related to the quality of the raw materials, the structure of the cloth, the knitting process, the degree of resin reaction and the pretreatment process. For stereotypes, under the premise of ensuring physical indexes such as shrinkage, PILLING, and distortion, minimize damage to strength. When these indicators cannot be balanced, priority is given to strength.

8, formaldehyde content

In general, high formaldehyde content is caused by incomplete resin reaction. The formaldehyde content of general adult clothes is required to be <75ppm. Some of the children's clothing and underwear, formaldehyde content requirements <20ppm. As long as the resin is fully reacted, the formaldehyde content of adult clothes will meet the requirements. For demanding children's wear and underwear, as much as possible, resin finishing. If you have to pass the resin in order to achieve other physical indicators, you can only arrange to return to the formaldehyde after the resin has passed, and then wet the mold.

9, PH value

The customer requested that the PH value of the fabric be weakly acidic or neutral, and the pH of the finished product should not exceed 8. NIKE, TOMMY and most domestic customers have strict requirements on PH value: light white PH range: 4.5-6.5. Therefore, all the cloths of these customers should pay attention to the strict control of PH value. The pH value is first adjusted in the dyeing tank by HAC, and is currently improved in SANTEX by 0.2G/LAC acid.