Jean Manufacturing Technology

Denim is unique in its manufacturing technology. It is first made of indigo blue dyed warp and sizing and then woven.

Dyeing and sizing

There are three kinds of denim warp yarn: indigo dyeing, rope dyeing, yarn dyeing and hanging ring dyeing.

The first two are joined to the sizing, and the latter is then dyed.

(1) rope dyeing and sizing

On the ball warping machine, 350~400 warp yarns are arranged with multi rope strands of 1 to 15 thousand meters in length, and then 12~36 strands are placed side by side into a continuous dyeing machine. After dyeing, they are dried and wound into a tube.

On the long chain warping machine, the rope like warp is further dispersed into a single warp yarn.

Then, these warp yarns are fed to the sizing machine and then woven into the weaving shaft according to the total number of roots required.

The disadvantage of rope dyeing is that dyeing, oxidation and water washing are not enough, and the equipment is large, generally covering an area of about 1000, and the height is about 8m.

(two) dyeing and sizing of flake yarn

Yarn dyeing is commonly known as warp.

(three) hanging ring dyeing

In this method, a dyeing trough is used, and the warp yarn is repeatedly dyed and repeatedly dyed in the trough until the depth requirement is reached.

It should be noted that because indigo has low coloring rate on cotton fiber and poor fastness to dyeing at high temperature, high consumption of powdered power and dark red color, it is used for dyeing at room temperature. This is the color characteristic of denim.

The air temperature is 80-100S at room temperature. In order to obtain pure color, indigo blue is oxidized by air instead of oxidant.

The washing temperature is room temperature.

In the process of washing, the floating color, residual alkali and impurities can be removed on the one hand, and on the other hand, it can be oxidized and fully oxidized.

In order to save indigo dye, we can use sulphur black instead of alkali cooking to dye it first and then dye it into indigo.

If the color of the finished product is red after dyeing, the amount of sodium hydroxide can be reduced, and the amount of the powder will be reduced if the color is green.

Two. Weaving

At present, shuttle weaving machines are widely used in denim weaving around the world, accounting for more than 80%.

In shuttleless loom

Because of the difference between the warp and weft yarn of denim, the evenness defects of the weft yarn will be exposed on the cloth.

In addition, sometimes the weft yarn is made of original yarn, because Huang Baisha can also create the weft file. In order to prevent this phenomenon, weft filling device can be used or the weft is dyed to light grey.

Large warp and large coils are used for weaving.

This is due to the coarse yarn, large turnover and fast machine cycle. Therefore, the large warp shaft must be used, with a diameter of 800mm and a 560mm of cloth roll.

If the coil is detached from the body, the large coil can be up to 1500mm (which can accommodate cowboy cloth 600m), but special delivery vehicles and verification equipment are required.

The change of weft tension can also produce a cloth cross.

Although the single weft insertion of shuttleless looms can avoid the tension difference between shuttle looms and shuttle looms, it is necessary to increase yarn storage.

Denim has large yarn width, wide amplitude and large warp tension.

For clear opening, the heald frame movement must be positive.

Some shuttleless looms still use springs to reassemble, which is not suitable for thick fabrics.

Therefore, the outer pedal device can be selected, and the pedal opening motion can accurately control the heald frame movement through the compound pedal.

The movement of the pedal is driven by the rotor rod, the pedal heald rod and the drive link of the heald frame, and equipped with the horizontal device of the shuttle level, so that all the heald frames can be adjusted to the same height.

The change of warp tension in weaving can also cause weft defects (especially weft breakage). Some looms with external pedal devices can solve this problem.

Because when the weft ends are broken, they are not allowed to move through warp let off, coiling and beating up.

The pedal can move independently and the meridional tension will not change.

The shrinkage rate of the cowboy is more than 10%, which can be reduced to less than 3% by preconditioning.

Shrinkage is generally required within 1.5-2%.

Desizing with BF---7658 enzyme has good effect, soft handle and no color.