Garment direct dyeing

1. The seams, welts and protruding parts can show a strong sense of contrast

2. Peach skin surface and soft hand feel

3. Good washing and sun fastness

Generally speaking, direct dye dyeing for garments should be applied to any cotton fabric, regardless of thickness or fabric. , The important part is the ecological pre-treatment method.

Direct dyes have a strong affinity for cellulose fibers such as cotton, viscose, and ketone. They can be dyed directly without adding any mordant during dyeing. , so it is called direct dye.

Direct dyes can be used to directly dye protein fibers such as silk and wool and synthetic fibers such as nylon in a neutral or weakly acidic bath. They can also be used to dye blended fabrics such as viscose/wool and viscose/nylon.

Direct dyes are classified according to their chemical properties, mainly azo dyes. In terms of application habits, dyes with light fastness level four or above are generally called direct light fast dyes; copper salts are used as post-processing Direct dyes are called direct copper salt dyes; dyes that require diazo dyeing post-treatment are called direct diazo dyes.

Because the structure of direct dyes contains hydrophilic groups such as sulfonates or carboxylates, their washing fastness is poor. Usually post-processing with metal salts or color-fixing agents can improve various dye fastnesses to varying degrees.

Direct dyes are easy to apply; have complete chromatograms; are cheap; have good level dyeing properties; and are widely applicable. Therefore, it is widely used in the washing and dyeing industry. Commonly known as cotton dye.

1. Properties of direct dyes

(1) Direct dyes are mostly powdery and have hydrophilic groups in the dye molecules. Therefore, they are easily soluble in water, and the aqueous solution is generally clear.

　(2) Adding alkali agents, such as soda ash, to the dye liquor can increase the solubility of the dye, thereby reducing the coloring speed of the dye on the fiber and producing a retarding effect.

(3) Adding salt or Yuanming powder to the dyeing solution can reduce the solubility of the dye to water, thereby increasing the affinity of the dye to the fiber, shortening the dyeing time, and producing a dye-promoting effect. Adding excess salt or Yuanming powder to the concentrated solution can cause the dye to salt out and precipitate.

(4) Most direct dyes will precipitate out of the solution when they encounter magnesium and calcium salts. The products are difficult to dissolve in water and consume the dye, so soft water is generally required for dyeing.

(5) Generally, direct dyes (azo types) decompose when exposed to reducing agents, destroying the azo group of the chromophore and generating colorless amino compounds, which cannot be oxidized to restore them. The fabric loses color, and the color remover developed by “Chinese Washing and Dyeing” is made based on this principle.

　(6) The above properties of direct dyes are common to direct dyes. Since many operators in washing and dyeing shops are not professionals, it is difficult to operate them correctly, and the knowledge about dyeing cannot be mastered in a short time. , Therefore, the Chinese Washing and Dyeing Technology Research Institute has developed special dyes suitable for garment counter-dying based on the particularity of garment counter-dying.

2. The main products of direct dyes

(1) Chinese products: Direct grass yellow, direct apricot yellow, direct peach red, direct bright red, direct snow green

Direct dark blue, direct golden camel (yellow brown) D3G) Direct grass green, direct smoke

Direct dark smoke, direct sky blue, direct gray, direct blue 2B Direct black G

Direct light-fast black G Direct lake blue 5B Direct green BE

Direct copper salt blue 2R Direct light-fast emerald blue Direct light-fast bright yellow

Direct red and green Lotus (Purple R) Direct Lightfast Fruit Green

(2) Other products: In my country, there are many manufacturers of dyes, and their product properties vary. For washing and dyeing shops that do not have strong professional knowledge, it is more difficult to use and dyeing accidents are inevitable. Therefore, I will not introduce them one by one here.

3. Dyeing methods of direct dyes

Direct dyes were developed after Paultig discovered Congo red in 1884. Because they can dye cotton fibers directly without mordants, they are called direct dyes. The ability of dyes to dye fibers directly is called directness.

Since most washing and dyeing shops are small workshop-style operations, they have neither professional knowledge nor large-scale professional equipment. Therefore, many domestic washing and dyeing companies have developed a variety of garment dyeing units based on the conditions of many domestic washing and dyeing shops to meet demand.

1. Dyeing of cotton fabric

(1) Weak alkaline bath:

Light color, medium color, dark color

Dye % 0.2-0.6 0.6-1.5 1.5-2.5

Soda ash% 0.5-1 1-2 2

Yuanming powder% 5-10 10-20 20-30

Bath ratio 1:20-1:30

(2) Neutral bath

Light color, medium color, dark color

Dye% 0.2-0.6 0.6-1.5 1.5-2.5

Yuanmingfen% 5-10 10-20 20-30

Liquor ratio 1:20-1:30

Dyeing method:

1. First, fully dissolve the dye and auxiliaries with an appropriate amount of hot water, then add clean water to make the dye solution the required liquor ratio. (That is, the amount of dyeing liquid is 20 to 30 times that of the object to be dyed). will have been soaked in moisture (old clothingThe dyed objects that need to be treated to remove color difference are immersed in the dyeing vat for dyeing. Continue to heat while constantly turning, so that the temperature gradually rises to 85-95 degrees Celsius. Continue dyeing for 30 minutes. When the temperature drops slightly, take it out and wash the floating liquid with clean water. Tumble dry or line dry.

2. Dyeing of viscose and ketone-ammonia fabrics

Direct dye dyeing of viscose fiber and ketone-ammonia fiber is roughly the same as cotton fiber. Therefore, this type of fiber has strong coloring, that is, the direct dye has a high affinity for viscose and ketone-ammonium fiber, especially the affinity for ketone-ammonia fiber. Therefore, it is not suitable for level dyeing. Therefore, when dyeing this type of fiber, light colors are not suitable for dyeing. When adding dyeing auxiliaries, the amount of dyeing auxiliaries for dark colors is also very small. Instead, an appropriate amount of penetrating agent and leveling agent should be added to achieve a leveling effect, and the amount of dye used should also be appropriately reduced. Light medium-dark color

Dye% 0.1-0.5 0.5-2

Penetrant g/L 1-1.5 1-1.5

Sodium hexametaphosphate g/L 0.5-1 0.5-1

Yuanming powder grams/liter 1-4

Leveling agent % 0.1-0.4

Liquor ratio 1:20-1:30

Dyeing method:

Fully dissolve the dye and auxiliaries, add to the dye bath, add water to the required bath ratio, the dyeing temperature is 40 degrees Celsius, in With constant turning, gradually raise the temperature to 80-95 degrees Celsius (add Yuan Ming powder if necessary), then continue dyeing for 1-1.5 hours, cool down to 60-70 degrees Celsius, take it out, wash the floating liquid or dry it in the air.

3. Dyeing of silk fabric

(1) Acid bath

Light, medium and dark colors

Dye % 0.5-1 1-2 2 -3

Acetic acid (30%) 0.5-1 1-1.5 1.5-2

Or Ammonium acetate% 0.2-0.4 0.4-0.6 0.6-0.8

Bath ratio 1:30 -1:40

(2) Neutral bath:

Light to medium color Dark

Dye% 0.5-1 1-2 2-3

Leveling agent g/L 0.5-1 0.5-1 0.5-1

Yuanming powder g/L 1-2

Liquor ratio 1:30-1:40

Dyeing method:

First use an appropriate amount of hot water to fully dissolve the dye and auxiliaries in the dye bath, then add clean water to make the required amount of dye solution Liquor ratio (that is, the amount of dye liquid is 30 to 40 times that of the dyed object). When the dye bath temperature is 40 degrees Celsius, immerse the soaked and wet dyed object into the dye bath (old clothing needs to be treated to remove color difference). Under constant turning, continueHeat, raise the temperature to 90-95 degrees Celsius within 15-20 minutes, continue dyeing for 45 minutes, take out, wash with water and dry.

Note: (1) If continuous dyeing is required, the soaked and wet dyed objects can be immersed in the dye bath at 80 degrees Celsius.

(2) Add 2-3 times, that is, a small amount and multiple times.

(3) When neutral bath dyeing is dark, after dyeing at 90-95 degrees Celsius for 15 minutes, the temperature must be lowered to 70-80 degrees Celsius before adding Yuan Ming powder, and then raise the temperature to 90-95 degrees Celsius , continue dyeing for 30 minutes.

4. Dyeing of viscose/wool blended fabrics

There are two methods for dyeing viscose/wool blended fabrics with direct dyes, namely the one-bath method and the two-bath method. The one-bath method mostly uses dyes that can produce the same color on wool and viscose fibers. The two-bath method uses acid dyes and direct dyes to dye wool and viscose fibers respectively to achieve the same color. When using the two-bath method, it is better to use direct dye varieties with less color stickiness in wool.

　(1) One-bath method (2) Two-bath method:

After dyeing wool with acid dyes, use alkali solution to adjust the pH value to neutral or weakly alkaline, and then dye it with direct dyes Viscose. When dyeing, an appropriate amount of retarder can be added to control the dye uptake rate and achieve leveling dyeing.

5. Dyeing of viscose/brocade blended fabrics

Most varieties of direct dyes are suitable for dyeing viscose/brocade blended fabrics, and their dyeing methods mostly use neutral or weakly acidic bath methods.

Light color, medium-dark color

Dye% 0.5-1 1-3

Penetrant % 0.5-1 0.3-0.5

Yuanming powder % 0-10 10-15

Ammonia sulfate % 0.5 0.5-1

Glacial acetic acid% 0.5 1

Liquor ratio 1:30～1:40

Dyeing method: