Learning points │ dyeing when using salt or use Yuan Mingfen [activity dyeing practice]
Yuan Ming powder and industrial salt are all salts composed of strong acid and strong alkali and are easily soluble in water. The chemical name of industrial salt is sodium chloride, which can be chemically generated from hydrochloric acid and caustic soda (HCI+NaOH → NaCI+H2O) . In the actual production, due to the cost, both substances are produced through mineral resources, such as evaporation from underground brines. Yuan Mingfen has no such effect. c. Comprehensive analysis Pre- sales Phase: we have sales representative to communicate with our client to understand client needs and based on our experience, capacity to initiate the draft proposal for our client review. With the proposal review, analysis and improvement, we will finalize our proposal with our clients. Cs Denim Fabric,Lightweight Denim Fabric,Blue Jeans Material,Denim Textile Fabric Foshan Aufar Textile co.,Ltd. , https://www.aufabric.com
1. Yuan Ming powder chemical structure
The chemical name of Yuan Mingfen is sodium sulfate, which can be chemically produced from sulfuric acid and caustic soda (H2SO4+2NaOH → Na2SO4+2H2O) .
Crystalline sodium sulfate formula Na2SO4 · 10H2O known as Glauber's salt;
2. Chemical structure of salt
3. Source of production
According to the description of the infecting users, both sources now have mineral resources. Yuan Mingfen has mineral resources in Huai'an, Jiangsu, Meishan, Sichuan, Hubei, and Inner Mongolia, but Huai'an and Sichuan provinces that produce the most are the underground brines. After evaporating directly under a slight treatment , the price is very cheap. Industrial salt is normally symbiotic with Yuan Mingfen, and the level of the content is determined based on the depth of the well. Huai'an's Jingshen and Huaihai are mainly salt-producing, and Yuanmingfen has fewer by-products; Hongze's salt mining is mainly based on Yuanmingfen, and industrial salt is less.
Yuan Mingfen is also a by-product of hydrochloric acid production: H2SO4+NaCI → Na2SO4+HCI ↑
There are two kinds of industrial salt preparation: 1. Sea salt production method; 2. Rock salt production method
Second, Yuan Mingfen and industrial salt application in printing and dyeing:
1. Accelerating agent
Yuan Ming powder and industrial salt can be used as dyes for direct dyes, sulfur dyes, vat dyes, reactive dyes, and soluble vat dyes for dyeing cotton fibers, and can adjust the dye uptake of fibers.
The refining mechanism of dye and fiber by Yuan Mingfen and industrial salt is basically the same. Due to the low dyeing rate of direct dyes, the dye is not easily absorbed by the fiber, and there are more residual dyes in the foot water after dyeing. Or industrial salt can reduce the solubility of the dye in water, promote the combination of dye and fiber, and increase dye uptake. In this way, the amount of dye can be reduced and the dyed color can be deepened.
2 retarder
Yuan Mingfen and industrial salt can also be used as dyeing agents for dyeing wool and acrylic fibers with acid dyes and cationic dyes, so as to reduce the speed of fiber absorption of dyes and achieve level dyeing requirements.
The mechanism of Yuan Mingfen and industrial salt for acid dye silk and wool as a retarder is: Both wool and silk are eggs. Fiber molecules contain -NH2 groups. When dyed with acid dyes in acid solution, the hydrogen ions H+ in the acid solution quickly diffuse into the interior of the fiber and combine with NH2 . NH3+ . The fibers are positively charged and the acid dyes are pigmented. The ion has a negative charge D- , due to the difference in charge between the fiber and the dye, which results in an ionic bond that is ·NH3 ·D . After adding Sin Mingfen or industrial salt to the dyeing solution, the negatively charged sulfate ion SO42- from the Yuanming Powder and the negatively charged hydrogen ion from the industrial salt can compete with the dye ion D- to preferentially dye the dye. The position of the -NH3+ root in the fiber is combined with ·NH3CI or (·NH3)2SO4 , and at high temperatures, D- replaces the position of the SO42- or CI- and dyes are dyed to achieve slow dyeing.
3. White color protection agent
Yuan Mingfen can also be used as a color protective agent for printing white silk fabrics ( or colored silk fabrics ) during dyeing and printing . In the scouring of printed or dyed silk fabrics, the dye may be exfoliated so as to stain the ground or other fabrics. Adding the powder may reduce the solubility of the dye, so that it will not stain and stain the soil. Industrial salt can also increase the absorption of naphthol when dyed. A certain amount of industrial salt is added to the base bath when naftu dyes cotton yarn, which can greatly increase the absorption of AS- type chrome.
4. Activator
Industrial salt can also be used as sulfonation media or sodium cations, as an activator in exchange resins and as an activator of pancreatic enzymes.
Third, application notes:
1. Add speed
The amount of Yuan Ming powder and industrial salt depends on the dyeing rate of the dyestuff and the depth of the tint to be dyed. It cannot be added too much or too fast. Too much will cause the dye to precipitate and the cloth will cause stains. Too fast, the dye is colored fast and easily uneven. Therefore, both Yuan Ming and industrial salt are water-solubilized before use, and they need to be mixed with a bath while slowly added to prevent the local dye bath from salting out due to contact with a large amount of accelerants.
2. Join order
a. General situation
Can not be added before dyeing (add dye first dyeing for a period of time plus salt). The concentration of the dye solution before solid dyeing is relatively high. If the Yuanming powder or industrial salt is added first, the dye-dyeing fiber is excessively fast and is prone to uneven dyeing. After dyeing for a period of time, Yuan Mingfen or industrial salt is generally added, that is, added halfway or may be added several times.
The dyestuff has the fastest rate of dyeing at the beginning, and then the dyeing rate will be slower and slower until the dyestuff is balanced. If you first add sugar and then add sugar, then the dye itself, the rate of rapid dyeing, coupled with the promotion of Yuan Mingfen, will cause the dye dyeing rate is too fast and easy to produce color flowers , usually after dyeing for a while Plus Yuan Mingfen.
When the dye concentration is large, the Yuanming powder can be added. It is not just the problem of dyeing flowers. I am afraid that there will be lakes (salting).
b. Practice exceptions
The affiliated netizens reflect: When many large manufacturers in Guangdong are using black or very dark colors, many use the first method of adding salt, add 10 minutes quickly , and then slowly add dyes. The method of adding salt should save at least half an hour. This method is not suitable for light or sensitive colors and is easy to spend.
This is based on your own habits (specific circumstances), some friends like to add Canadian dollar powder plus dye, some friends like to add dyes and then add Yuan Mingfen, but no matter which addition method, you must remember that after The added one must be slower.
According to the structure of the dye used, the dyeing process conditions of whether the salt is added first or the salt is selected according to the directness of the dye.
The theory of dyeing depends on the equipment changes. The air cylinder requires the first Canadian dollar powder. In addition to the light color of 0.5% or less, it is generally not considered after adding the Canadian Yuanming powder. The human cotton is also the same.
In fact, this is just a matter of design rationality (the conditions for ensuring quality and lowering the cost and improving efficiency). According to the equipment leveling ability, leveling dyeing easy (such as cotton and cotton), dye properties (such as direct, active base), color type (Dahong Tibetan blue and gray coffee, the same dye combination of solid color System and intermediate colors, compatibility, dye usage, and solubility under salt conditions (ie, salting out). General: Solid colors, dark colors are used more often. The biggest difference is the simplicity of operation , saving time and improving efficiency;
In the case of dark colors, such as red and black, which are relatively easy to be stained, first adding Yuan Ming powder can obviously save time , increase efficiency, and control the color light easily, and the operation of workers is also more convenient.
(The author's note: In general, the main purposes of adding dyes after adding salt first are: to increase efficiency, to facilitate the operation, to save time, and to facilitate the dissolution of salt. However, the potential hazards involved are also great, such as color flowers and salt precipitation; Therefore, unless special circumstances, special equipment, is not recommended to adopt this method, which is the reason behind the current plant more salt, after all, the production of " stability " is far more important than the efficiency and save money.)
Fourth, the difference between the two:
1. The amount of difference
The difference in dosage, the relationship between the two is: 5 parts of industrial salt = 6 parts of anhydrous sodium sulphate = 12 parts of crystallization of Yuan Mingfen. 100 parts of anhydrous sodium sulfite, 100 parts of industrial salt yttrium, 227 parts of Crystalline Mingfen. Because the molecular formula of crystalline sodium sulfate is Na2SO4·10H2O with a molecular weight of 322.2 , and the anhydrous sodium sulfate molecular formula is Na2SO4 with a molecular weight of 142.06 , ie, 2.27 times that of anhydrous sodium sulfate as crystalline sodium sulfate .
Therefore, the amount of anhydrous sodium sulfate and industrial salt is basically the same. If crystalline smelting powder is used, its amount is double the amount of anhydrous sodium sulfate or twice the amount of the field.
2. Reasons for promoting the use of Yuan Mingfen
Practice has proved that when using Yuan Mingfen as an accelerant, the dyed tint is brighter and brighter, and when industrial salt is used as an accelerant, its effect is poor. This is related to the purity of industrial salt. Because the general industrial salt, in addition to containing more calcium, magnesium and other ions, it also contains a small amount of iron ions, and some dyes are affected by iron ions will cause dark shade.
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