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Nantong Fangbing Chemical Co., Ltd.
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Twelve major uses of soda ash in the printing and dyeing industry

1. Softener:

In order to avoid the formation of water-insoluble calcium, magnesium soap or dye deposits during the printing and dyeing process, appropriate methods can be used to remove calcium, magnesium and other salts in the water. This process is called water softening.

Adding soda in the water can make calcium or magnesium ions become carbonate and precipitate out, so as to achieve a softening effect.

2. Scouring agent:

The colored yarn fabric is made of dyed yarn and raw yarn without washing and bleaching. The ratio of the two varies from species to species. Like lattice, the proportion of colored yarn is very large, while the proportion of poplin is much less. The scouring of colored yarn fabrics cannot be done with ordinary cotton, because most of the yarns in the fabric are dyed with dyes such as vulcanization, reduction, and Nafton.

When these dyes are boiled in a high-temperature and high-pressure caustic soda solution, they are easy to dissolve and dye into a white background color, resulting in serious color matching. Therefore, it is impossible to use caustic soda when cooking lattice and poplin poplin, but soda alone can only be used, and it cannot be pressurized during the cooking process, but should be carried out in an open cloth cooking pot under atmospheric pressure . Avoid peeling off the color of the yarn and polluting the white ground.

3. Emulsifier:

Raw wool fiber is not suitable for textile engineering because it contains a lot of dust and impurities, so it is necessary to wash the raw wool before spinning. Generally speaking, the use of soda water and soap can convert the fat impurities in the wool into an emulsion and remove it.

The method is to add 3-10 parts of soda water and 2-5 parts of soap to every thousand parts of water, stir and refine at 45℃, and then wash with warm water.

4. Scouring agent:

Wool and wool fabrics are refined due to the original wool, and only lubricating oil and stains are removed during the textile manufacturing process. The process is much easier than raw wool. The fabric weight is usually 2-4% soda water and 1-3% soap, and the temperature is 35-40°C.

5. Silk scouring agent:

Silk fiber is mainly composed of silk fiber and silk glue, with few other impurities and only a trace of wax fat. The content of silk glue is about 30%, covering the outside of the silk fiber. Although its chemical composition is similar to silk fiber, it lacks luster and is rough and hard. In order to give full play to the soft luster of silk, silk glue must be removed.

Silk glue can be softened and dissolved in hot water containing soap and weak alkaline, while the fiber quality of silk is insoluble. With this function, soap scouring and soda scouring can be performed.

6. Dyeing auxiliaries for cotton:

As a direct dyestuff, soda water can lighten dyeing and soften hard water. When dyeing cotton with sulfur dyes, sodium sulfide is used as the dye solvent, and a large amount of soda water is often added to help dissolve the dye. If the effect of the alkali is very sufficient, there is no need to add soda water. In addition, if vat dyes are often added together with some soda to be used as auxiliary dyes.

7. Color paste alkali:

Some reducing dyes, such as Shihlin brilliant pink R and blue 3G, are prone to oxidation and are sensitive to caustic soda. Therefore, when a strong base is used as the dissolving base, the color after printing is darker and usually emits purple light. To overcome this shortcoming, soda is often used instead of caustic soda.

In addition, due to the strong hygroscopicity of caustic soda or potassium carbonate, some color pastes used for color drawing printing at steam usually produce color halos in the green of the flower side. To overcome this problem, soda is often used instead of caustic soda or potassium carbonate. A suitable base is soda ash used for RRD.

8. Decontamination agent:

Use soda ash and soap as cleaning agents when handling colored and printed cloths. Soap is the sodium or potassium salt of fatty acid, which is a good detergent. The soap will be hydrolyzed in a dilute solution, and when the concentration reaches 0.16-0.2%, the washing power will reach its peak.

In order to obtain sufficient decontamination ability, especially when there is more dirt, its concentration should be increased to about 0.5%. In order to inhibit the hydrolysis of soap in a dilute solution (less than 0.1%), 0.1% soda water can be added to the washing solution. The soda water content in the concentrated solution should be reduced. Alkali softens hard water, thereby acting as a soap.

9. Fixing agent:

When reactive dyes are dyed on cotton or synthetic fibers, they are fixed by alkaline substances. Good results can be obtained by using dilute solutions of weakly alkaline substances (such as sodium carbonate). The dosage can be increased or decreased according to the color density.

For example, when rolling is performed with ordinary reactivity, most of the time in the 5th to 6th passes, about 1% of soda ash is added to the dyeing bath as a fixing agent. Generally, dyeing is 6, fixation is 6, and the temperature is 20-21℃.

10. Anti-whitening agent:

When preparing nigrosine anti-dyeing and printing anti-white paste, in addition to zinc oxide powder and brightener, there is about 70-100g/L soda water. The hydrochloric acid in the nigrosine dye composition is offset, so that the nigrosine cannot be colored. , So as to achieve the anti-whitening effect. Sodium acetate can also be used as a dye inhibitor instead of soda, but the white outline is not as clear as soda.

11. "Wind Seal" agent:

Reactive dyes contain reactive groups, which can be combined and fixed with fibers. At present, the common dyes are low-temperature fixation (X-type or ordinary type) and high-temperature fixation (K-type or thermosetting type). Editor without borders

The advantages of reactive dyes directly printed on cotton cloth are bright color, good fastness, and are not affected by photochemistry and fiber brittleness. But it also has the disadvantage of not being able to resist chlorine drift and the so-called "windmark".

"Windmark" refers to the irregular color of printed products exposed to the air. This is mainly due to the neutralization of the exposed air and acidic gas before steam-fixing the printed fabric, which weakens the alkaline agent for fixing the dye. Therefore, pre-rolling white fabric with enough alkali (usually 20 g/L soda ash) can not only fundamentally overcome the problem of dye wind printing, but also significantly improve the color supply. In addition, the printed cloth is also wrapped with film or cotton cloth so that the cloth will not be partially exposed. After steam cooking, there will be no wind defects.

12. Clarity:

Condensed turquoise i5g is printed directly on the cotton cloth. The white grey fabric is pre-rolled with enough alkali agent (20 g/L soda ash), and steamed after printing, which significantly improves the color of the dye, the washability and the clear outline of the band.

However, baking soda cannot be used as an alkali in printing pastes instead of baking soda. Because you can use 10 grams/liter of soda water instead of 10 grams/liter of soda water. Although it can shorten the steam cooking time, it has a darker color and poor color paste stability (3 to 4 days with baking soda color paste, and only 8 hours for baking soda paste).

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