Printing and dyeing cloth quality problems and prevention and control methods (worth collecting)

The guide reads "Recharging" 5 minutes a day, quite 2 hours! 1 1 Formation and Treatment of Singeing and Burning

In the dyeing process, sometimes there are two or more black folds on the surface of the fabric after the padding and there are hairy white tops next to the black folds. This type of fold is a singe-folded fold. After this kind of zigzag baking, a white print appears, and after the reduction of color, it is a dark, deep trace. The singeing is due to the singeing of the cloth when the surface is not smooth and passes through the crater. When the crater is burned, it is formed due to the high temperature of the crater. The crease is not burned, so there is a white wool strip beside the black crease. .

Prevention: First, it is not possible to singe the broilers and formulate a reasonable production process according to different fabrics. For thick fabrics, they should be piled or boiled before singeing, so that the singeing process can reduce the possibility of singeing machines. That is, the singeing uses a wet falling cloth to prevent the falling cloth temperature from increasing to a high degree.

If singeing is found during dyeing, it must be reprocessed before dyeing. Once the car is dyed, it will not be processed. The method of pre-processing and repairing singeing and folding skein is very simple, as long as the high-temperature setting will flatten the fabric and then reburn singeing, then low-alkali mercerizing can eliminate singeing and folding.

2 2 Formation and Treatment of Boilers

Bleaching is more common in high-strength high-density polyester-cotton fabrics and cotton thin fabrics. The water hardness in the production of large scale when used to steam easily adhere to the guide roller, prolonged production will form scale groove marks, so that the cloth guide roller is not Flat, the fabric will be easy to make folds. Once found in the production of sub-folders should be cleaned in time to clean up, found that semi-finished products have a fold when dyeing, should use a reasonable process repair.

Introduce several methods for repairing the folds:

(1) Drifting to cloth if it is not smooth temporary creases or mercerized drying folds, lighter than the direct dyeing does not consider the impact of dyeing, if relatively heavy as long as the predetermined type can dye production.

(2) If there is a clear fold in the cloth, no fabric damage will be formed, and the dyeing machine will be a black fold. If the fold breaks down the fabric, it will be a white fold. For this kind of fold, high-temperature ultra-widening and mercerizing can be used for repair.

(3) Drifting is serious due to blindfolds, and Aurora marks have already been formed on the creases on the fabric. This type of fold is more difficult to handle. Aurora printing is ground flat, then boiled and bleached, and the damaged fabric fibers are expanded and repaired. Finally, the creases are leveled by a high concentration of alkali mercerizing treatment.

In this emphasis, it is crucial to accurately determine the cause of the creation of an essay, and different methods of handling the divination are different to avoid wasting unnecessary processes. For example, mercerized dried creases are better found, they should be treated in time after the discovery, and do not leave the problem before dyeing. If it is difficult to deal with the dry creases, it can be used to play the axis when the mercerized cloth is dropped. This will dry the folds and flatten the fabrics with the remaining temperature of the cloths to make the creases flat. This will save the stereotypes before dyeing. (Styling before dyeing has several drawbacks: high cloth temperature is easy to form creasing. Styling effect is not easy to appear off needles. For sensitive colors, it is easy to form white edges and other defects. Pre-styled dyeing will add heavy rain Shaped flower cloth noodles, so it is better not to shape the semi-finished product before dyeing, if it is necessary to set the temperature should be controlled at 170-180 °C.)

3 3 Formation and Processing of Track Printing

Crawler prints appear more often in heavy fabrics, and are also tracked during dyeing. However, due to the different forms of formation, the appearance after dyeing is different on the fabric (black print, white print).

The commonly seen trackprints are latitudinal sloping black crossprints. This trackprinting is due to stacking indentations caused by too thick fabric piles in the crawler box. Sometimes, if the trackprints are lighter, they need not be considered. Dyeing machine is not too obvious, if this kind of fold is too obvious as long as the heat pile can be removed again. However, another type of white strip track may be rarely encountered, and it is not clear why this is caused by the track. We all know that in order to produce safe steamed caterpillars, saturated steam is used to heat the water in the tanks of caterpillars to produce saturated steam to treat the fabrics. However, if the water level in the caterpillar tanks is too low, the caterpillars will be filled with water (240 °C high temperature superheated steam, so that the track plate (roller) will be too high to burn the fabric contact surface to form white spots, and the longer the stacking time, the heavier the white spot, once the equipment platform fails, the white strip will be It is difficult to repair, so I think this white stripe is also caused by crawler, and we will classify it as trackprint.

Once formed, this type of white strip crawler is very difficult to remove because it is caused by fabric damage, so it must be strictly prevented in production. Stoppers should pay attention to the stacking form, thickness, and water level in the crawler box when driving. Less can not be flooded box).

If dyeing is found in this white strip track should be how to deal with it?

A hot caustic heap process was used, followed by concentrated alkali mercerization to increase the penetration of the scald. Even after such a repair, the heavy crawlers are still printed in white.

The following can only improve the dyeing process to make up:

(1) For lighter track prints, the dip time can be extended by using two dips or two rolls or a pressure roller in the feed tank to reduce the track print.

(2) For relatively heavy trackprints, two-bath dyeing is used. First dyeing with 50% dyeing and dyeing once again can significantly improve trackprinting to achieve customer satisfaction.

(3) For particularly heavy track prints, if the list has been bleached, it will be bleached, otherwise dyeing can only be done with dyeing to maximize the track print.

4 4 Causes and Prevention of Bleached Cotton Spots and Holes in Semifinished Products

Bad cotton spots are generally formed during oxygen bleaching. When bleaching, the rinsing liquid contains rust and other impurities adhering to the surface of the fabric. Under the action of the metal ions, the hydrogen peroxide will violently decompose to generate a large amount of heat and damage the cotton fiber. The fiber damage is accumulated in the track steamer and is subjected to high temperature and long time heaping. Place will form bad cotton spots or holes.

In addition, when the singeing burnt cotton wool sticks to the surface of the fabric, it will also form a point of oxygen bleaching where it will also here, was severely burned by hydrogen peroxide to form burned cotton spots.

The effect of rotten cotton spots on the dyeing quality:

1) When the bright color is dyed, bright spots are formed at the rotten cotton spots;

2) When dark and dark colors are stained, dark spots are formed at the rotten cotton spots.

3) For polyester-cotton fabrics, the severity of rotten cotton patches depends on the difference between the color of polyester fibers and cotton fibers. When the hue is close, the stain will be reduced.

4) When the hue difference is large, the stain will increase.

If the spot formed by rotten cotton spots is found, it is necessary to adjust the consistency of polyester/cotton as much as possible to reduce the gloss difference of polyester/cotton fabrics, and to minimize the impact of rotten cotton spots on the quality of colored fabrics.

If a bad cotton spot is found during the dyeing process, it should be notified as soon as possible of the bleaching treatment to minimize the loss, and adjust the dyeing prescription to reduce the degree of bad cotton spots.

According to the reasons for the formation of bad cotton spots

Take the following measures to prevent:

(1) The container containing the rinse solution should be clean and must not contain metal impurities such as rust. The soft water used should also be clean and cannot be contaminated once by the rust hose. In addition, oxygen bleaching cloth can not have rust, there are rust spots should be treated before oxygen bleaching.

(2) Oxygen bleaching process should be safe, reliable, and tolerant, and additives (stabilizers, penetrants, chelating dispersants, water glass, etc.) should be quantitatively reasonable, in order to prevent severe reaction of hydrogen peroxide from forming holes or rotten cotton spots, and to produce thin fabrics. Hydrogen peroxide content should be appropriately lower.

(3) When oxygen bleaching is used, wet cloth should be used to prevent rust or over-burning points from reacting violently with hydrogen peroxide. Wet cloth also compensates for fabric infiltration and inconsistent whiteness due to process fluctuations.

(4) When the fabric quality is poor, there are many fabric neps and dead cotton. During the production of the sanding machine, due to the influence of the exhaust bristle roller and other factors, the surface of the cloth may be adhered to cotton wool to varying degrees. If the brush bristle box is not completely treated during singeing, the cotton wool accumulates more and continues to be brought to the crater, resulting in When cotton ash falls on the cloth, it will cause scorching on the cloth surface, forming black and yellow spots. This carbonized cotton ash ash reacts violently with hydrogen peroxide during oxygen bleaching, causing the fabric to form rotten cotton spots.

In the production of cotton fabrics should pay attention to:

1. The brushing effect of the sanding machine is better than that of the brushing machine, and the cotton wool cannot be allowed to fly everywhere and adhere to the cloth surface;

2. When singeing, pay attention to cleaning the bristle box to eliminate the possibility of cotton wool ash being formed when the bristle is brought to the crater. Use a damp cloth to prevent rotten cotton spots.

5 5 Causes of Alkaline Spots and White Spots and Preventive Measures

If bleaching cloth is not clean, it will make the fabric uneven, whiteness inconsistent, and there will be a piece of macular (alkaline spot) when setting or baking at high temperature.

Alkali spot is caused by the insufficient washing of the mercerizing machine, the adhesion of a large amount of alkaline cotton wool on the guide roller, and the drop of alkaline water (different from the yellow rust point) during drying. Alkaline spotted silk cloth is invisible, but it will be seen at high temperatures.

If the drip-dried water droplets of the mercerizing machine are clean (due to vapor condensation) and are colorless and alkali-free, the white spots will be seen by the bottoming machine and the over-rolling car, but the white spots will not appear after the continuous dyeing machine develops color.

If the water spot of the mercerizing machine is a dirty yellow rust spot, the mercerizing machine can clearly see the falling cloth. At this time, the dyeing machine must be treated in time to be dyed and returned for dyeing because the stain after the spot dyeing is a dark spot, and once dyed Can't handle it.

If the fabric has a yellow spot after being mercerized, first of all, it is necessary to analyze how the macula is formed and to take correct measures.

If the macula is only a rust spot, there is no damage or hole in the fabric and it needs to be washed with oxalic acid before dyeing;

If the macula is caused by residual lotion (acidic) during drying, it should be stopped immediately. The spotted fabric can be seen to have fabric damage (polycotton fabric) or broken holes (the pickling water is The cotton fabric is burned out of the hole when it is dried at a high temperature). For polyester-cotton fabrics, if the spots are heavier, they are like rotten cotton spots. If the cotton fibers remaining at the light spots are not dyed, white spots will be formed after dyeing.

This phenomenon has been seen in the dyeing shop dispersion / activity two bath dyeing.

Production process: decentralized rendering → baking → reduction cleaning → bottoming dyeing activities → steam solid → washing → soap boiling and drying.

During the dispersion reduction cleaning, the drying drum has a drying tube detergent residue, and water droplets form on the fabric during the production to form a yellow spot. At that time, no attention was paid to it. When the dyeing activity was found, the fabric was found to have white spots. . In order to recoup the losses as much as possible, the oxalic acid degreaser was used and the re-reduction cleaning was ineffective. Later, considering that the cotton fiber damage was caused by acid, in order to increase the dyeing rate of the cotton fiber, the mercerized fabric was cold mercerized with concentrated alkali, so that the remaining cotton fiber had a significant improvement in the whitening ability of the dyeing ability.

To avoid such accidents, you can take the following measures:

(1) The macula should be treated in a timely manner after restoration and cleaning, and the cause of the macula should be analyzed accurately. Ensure that the dryer is clean and free from acids.

(2) Reduction and cleaning can not be done, and the indeterminate type before dyeing is used to prevent the high temperature setting process from intensifying white spot when there is acid water.

(3) Once an acid macular spot is found, the mercerization should be performed after the dyeing of the cotton fiber before dyeing. This is because it has been proved that if the active reprocessing is first carried out (including cold mercerization, it is difficult to remove white spots), white spots It will be very heavy.

In the bleaching production, if the rinsing and bleaching is not clean or the scouring alkali contains penetrant and other dirt, it will be difficult to remove the roller compacted on the surface of the cloth during the production. When dyeing, the Shilin dyeing machine will fall into the cloth. Dark spots, but the continuous cloth is not obvious; but if the dyeing with reactive dyes is just the opposite, dyeing machine without any traces under the paint, continuous steam solid color after the deep spots are very serious. For this reason, in the production of active dyeing products, we should pay attention to the color test. Once we find that deep spots should be reduced and cleaned, then re-staining will be insignificant. After dyeing, the re-spotting activity after stripping can also remove the spots. . (usually pink with red spots, purple with black and blue spots, bright green with bright green spots)

There are many reasons for the formation of leukoplakia, such as the dyeing machine water point, restore the steamer water point, if the water point in these places is whiter, it is produced in the front position, and lighter is in the back position; the water point is more round than the cloth. In the places where the height of the route is small or where splashes occur, the strips of water spots are generated by places where the height difference of the route is large. Other white spots, such as mercerizing rollers, are rolled with woven bag strips, which cause white spots to appear during the dyeing process. If the mercerizing roller mills with cotton wool, dark spots are formed during dyeing. There are many other reasons for the formation of leukoplakia, such as wax spots, alkaline mud, and rotten cotton spots introduced in other chapters.

6 6 Formation and Treatment of Alkali Mud

In the dyeing production, the situation that the white spot and the wax stripe has been known from time to time has occurred. However, the alkaline spots and wax strips are not obvious after drying, but they are still very obvious after drying. They are white spots with sticky paste. This is mud alkali.

Alkali mud is formed by the muddy alkali that is too dirty and has sludge. It is deposited in the alkali tank or the bottom of the tank. Sometimes heated steam blows the alkali mud and adheres to the surface of the cloth. It is difficult to wash it down after rolling in the rolling mill to form white spots. Sometimes the flat seam head is too wide, and the bottom alkali is hung on the surface of the cloth. Sometimes the production breaks the bottom of the tank and causes the bottom sludge to adhere to the surface of the cloth. The occurrence of these alkaline muds is caused by the dirty deposition of mercerized alkali. In order to prevent the occurrence of alkali mud, the mercerizing machine should be regularly cleaned to prevent the appearance of alkaline mud. In addition, the last two counts of the mercerizing machine should be added to stabilize the acid to neutralize the mercerized alkali. Reducing the occurrence of alkali spots also ensures the pH of the semi-finished fabric before dyeing.

What is the treatment of alkaline sludge found in dyeing production?

If alkali mud is found in the production, the bleaching process should be promptly notified to clear the mercerizing machine in time, and to prevent the production of semi-finished products and alkaline sludge. Alkaline mud treatment is very simple, as long as the pickling can be removed, even if it is padding dyeing continuous found after the machine can also be pickled alkaline mud washed white spots. Alkali mud although it looks like white spots, but it does not affect the dye on the fabric dyeing, but the surface of the cloth is stuck with a layer of something like pulp, after washing the alkali mud is very good, no significant defects.

7 7 Effect of Wax Strips and Heterotrope on Dyeing and Handling

Due to the uneven quality of the grey cloths , the sizing agent used by each weaving factory is also different, which causes serious problems such as heavy fabrics and heavy impact of the fine woven fabrics. In particular, the addition of paraffin to the grey fabrics produced by some small textile mills can cause serious waxy strips during the dyeing process, resulting in serious dyeing cloth noodles and white spots (especially in the blue series).

Therefore, if bleached pre-production inspection fabrics contain more wax, be sure to first remove the wax (generally using the state paste), and do not take the singe first (the effect of wax removal is poor after high temperature). If the wax strip is found before mercerization, the softening agent can be rolled and then mercerized. If the wax strip is found before dyeing, the wax strip can be firstly dyed after drying at low temperature and the wax is dried.

When the cotton fabric is dark, sometimes there are more white stars on the cloth under the dyed cloth, and there is fluorescence under the ultraviolet light. This is caused by the opposite yarns. If you know that the gray yarn has an opposite yarn, you should bake the yarn after baking. Drifting, if dyestuffs are found before dyeing, they should be dyed before the yarn is baked. If the heavier yarn is dyed, heavier yarns will affect the shade after dyeing. (Due to dyeing, the dyes will migrate to cover the opposite yarns. It is good, but it affects the fastness and color fastness of colored cloths and colored cloths.

8 8 Inappropriate treatment of cotton stains, dead cotton, cotton wool and slurries

If the quality of the grey fabric is good during production, the dyeing has a high dyeing rate and a good dyeing depth, and the fabric surface is smooth and even and plump. If the fabric is of poor quality, the dyed white stars and cloth noodles are seriously damaged. Therefore, in the case of fabrics containing a lot of dead cotton and cotton, it is necessary to strengthen the pre-treatment process and ensure that the production is safe and reliable. At the same time, as much as possible to clean the cotton, the cooked cotton will be thoroughly cooked, and the dyeing rate and the quality of dyed fabrics will be improved.

Because of the energy saving, the cold-reactor fabrics are now used by many companies. However, the cold-piles remove the cotton miscellaneous materials and the poor effect of the cloth is more compacted. Therefore, it is easy to extricate the fabrics during dyeing, and the guide cloth sticks are easily stained and stained. Spot, so the production of dyeing to add less viscous additives, such as: anti-migration agent, brightener NT-2 and so on.

When producing polyester-cotton milled fabrics or pure cotton thick fabrics, if the bleaching process produces poor cleaning results, the cotton wool is not cleaned properly, and some fine cotton wool will stick to the surface of the fabric. After the rolling mill is compacted, it is more difficult to remove, and white spots are formed during dyeing. . Some white-stained dyeing machine is not obvious, but if you reverse the cloth surface by hand, cotton wool will fall and you will see a lot of white spots. It is very difficult to remove fine cotton lint on the surface of the fabric. Dyeing is difficult to find in continuous dyeing machines, but when tentering is required to add viscous additives such as anti-wrinkle agents, rain-proof agents, and cross-linking agents, the cotton wool sticks to expose white spots. . Therefore, the white spots caused by cotton wool can not be underestimated, in the production of grinding products, should pay attention to clean up the fan hair dryer, exhaust fan, bristle roller at the cotton wool, to prevent adhesion on the cloth surface, the roller mill rolling mill is difficult to wash Down. If you do not clean the cotton wool on both sides, you can use a bristles roller to brush it again on the sanding machine, and then dye the cotton wool to clean it.

For fabrics with more cotton and dead cotton, raising the alkali concentration (220 g/L) during mercerization can effectively improve the quality of the cloth surface and reduce the white star and cloth noodles.

After grinding, the ground fabrics must pay attention to the aurora mark, because once the aurora is printed on the dyeing, white spots will be formed. Therefore, the rolling mill and the guide cloth sticks after polishing can not adhere to hard objects. Inspect the groundwork. Auroral white spots are found during dyeing and should be disposed of.

9 9 Dirty gas formation and prevention during dyeing

In the production of colored fabrics, orange and glossy powders are often produced, and fluorescent materials are used to produce them. However, under the production opportunity, it is found that there is a layer of black gas on the surface of the fabric and the fabric is particularly flowery. This is pollution.

Dirty gas is usually caused by the following conditions:

(1) Singeing is not clean. If the singeing effect is poor, a short layer of fuzz will remain on the fabric. During the dyeing process, the infrared light of the bottoming machine will be too close to the fabric, and the speed will be slow. Infrared rays will bake the short fuzz on the fabric and form a dirty gas. The production of dark colors is not obvious, but the beautiful colors will be obvious.

(2) Inappropriate choice of materials causes a seemingly dark atmosphere. If the dispersion material used in the production is made of fluorescent material and the active material is made of darker dyes, it will cause the cloth surface to produce a layer of dark and dirty air due to the inconsistent color shade. Moreover, the polyester-cotton fabric itself has a higher brightness than cotton, and dyeing is particularly bright. Polyester and cotton are liable to cause inconsistencies in hue. Therefore, when producing brilliant colors, the cotton treatment should be strengthened to ensure the whiteness of the fabric, so that the color of the fabric and cotton are basically the same. Prevent the generation of dirty gas.

(3) Improper formulation of dyeing process. For example: choose to disperse fluorescent red, disperse fluorescent pink, disperse purple mix and produce bright pink. If the baking temperature is low, then the dyed fabric will be dark and flowery, and if the baking temperature is high, the fabric will be bright and full after dyeing. In this case, because the dispersed fluorescent red hot pink can fully express the color and reflect the beautiful fluorescent effect, it should be based on the The use of dyes to develop a reasonable production process can produce brilliant full-color fabrics.

For more details, please pay attention to China Grey Fabrics ( )