What is Acid Dye - What is Acid dye used for and How to make Acid dye?

New dyers are often unaware about acid dyes, because they believe the dyes to be corrosive, flesh-eating caustic acids. Let’s learn through this article What is Acid Dye, What is Acid dye used for and How to make Acid dye with easy and detailed explanation.

What is Acid Dye?

Typically, We can say acid dyes are applied straight from an acidic bath since they are anionic, water-soluble, and corrosive. Because of the ionic link formed between the protonated -NH2 group of the fiber and the acid group of the dye, wool, silk, and nylon can be colored with these dyes despite their acidic groups (SO3H and COOH). Lightfastness is excellent but wash fastness is generally poor. Since the electrical natures of the dye and the fiber are opposing, the strike rate and uptake of acid dye on these fibers is faster; a more concentrated electrolyte is added to slow down dye uptake and to generate uniform hues. The fiber becomes charged with cation as the acid reacts, and the negative charge is neutralized by the dyeing molecules as they are heated.

Acid dyes are those that are used on fabrics at acidic pH levels. As opposed to cotton, they are typically used to colour wool.  Certain acid dyes are utilized in the food industry as colorants, while others are put to use in the medical field to stain organelles.

Acid dyes used in home dyeing are actually non-caustic and rather safe to work with. Some of them, like the ones used as food coloring or in popular drink mixes, are even edible (safety warning: never eat dyes).

Acid Dyes should be treated with the same caution as any other intense powdered dye or craft chemical when used for at-home dyeing; that is to say, always use protective gear (such as a dust mask and gloves) and have a clean work area.

Source: Wikipedia

What is Acid dye used for?

Protein fibers like silk, wool, angora, alpaca, mohair, feathers, etc., as well as synthetic Nylon, which is chemically identical to silk, can be dyed using acid Dyes. The acid component of the term originates from the fact that a very mild acid, such as household white vinegar or odorless Citric Acid, is used to reduce the pH of the dye bath so that it is slightly acidic, causing the dye to link to the protein fibers. On the other hand, an alkaline dye bath is required when working with Fiber Reactive colors on cellulose fibers. Proteins respond better to somewhat acidic dye baths than to alkaline; they tend to stay softer, and silk retains its sheen, therefore Acid Dyeing may be preferable to other types of dye for protein fibers. Those who work with silk on a daily basis would typically advise a vinegar rinse after dying the fabric so that the silk can regain its suppleness.

Acid Dyes get their name from the fact that they require a somewhat acidic "fixative," such white vinegar or citric acid, and have acidic chemical groups like -S03H. Protein fibers (including nylon) can be colored with acid dyes because they share a common structural component—amino groups (-NH2)—with the dye, which forms a covalent link with the fiber via a sulfhydryl (-S03H) group. Hydrogen bonds, Van der Waals forces, and ionic bonding are hypothesized to be responsible for the fastening of acid dyes to fibers.

The sulfonic or carboxylic acid salt functional groups can be found in one or more of the big pigments known as acid dyes . Since positive charge buildup inside the fiber in acid solutions works as a driving factor for dye diffusion and migration into the fiber, these dyes are dyed onto fibers from an acid solution. Acid dyes are only effective on fabrics that acquire a positive charge in the presence of acid, such as wool and other protein fibers, nylon, and some modified synthetics. Generally speaking, acid dyes on fibers have good fastness qualities to both light and laundering, although these capabilities can be further improved by mordanting (a more complete insolubilization of the dye via interaction with a metal salt). Although mordanting can alter the dye's color slightly, pre-metallized acid dyes are a unique type of acid dyes that have been pre-reacted with a mordant and are still soluble enough to be dyed using the same circumstances as regular acid dyes.

How to make Acid dye: Basic instruction

In this part of article I’ll tell you how to Use Acid Dyes to Color One Pound of Fiber

Prior to being dyed, fibers or yarn should be cleaned to remove any oil, dirt, or sizings. Dyeing over existing colors is permitted.
Put a quarter of an ounce of the powdered dye into the cup and add just enough water to produce a paste. To help the dissolving process along, add extra warm water. To achieve a softer color, use less dye.
Fill the dyepot with lukewarm water (about 2.5 gallons' worth). After the dye has been dissolved (in Step 1), pour it in and mix it around.

Place in a bowl and carefully mix clean, moist yarn, fiber, or fabric. Ten minutes should be allotted for soaking, and no additional heat should be used. Then, after letting the dyepot sit at room temperature for about 10 minutes, bring it to a temperature of around 120 degrees Fahrenheit. For even dye coverage, gently poke the strands.

To fix dye, add 2 cups of white vinegar (use 1 cup if dying 1/2 pound of yarn). The first time you stir it after adding the vinegar for 5 minutes. After that, stir it gently every 4 to 5 minutes. Once the dye water begins to simmer, it will take about 30 minutes. (190° - 212°). Keep at that temperature, stirring gently every so often, for about half an hour, or until the water is the shade you want. As long as the wool is not "shocked" by going from extremely hot to extremely cold, boiling it is safe.

Take the yarns out of the pot and  rinse in hot water. Use warm soapy water and rinse thoroughly. Instead of letting the spray strike the yarns, squeeze them in a towel or spin them in the washing machine. No sinks or pots will be stained by these colours.

Safety Warnings Please Follow:

Please only use enamel or stainless steel dye pots. Neither aluminum nor galvanized should be used. Do not use this pot for food. NEVER put your hands or arms completely into the dye. Not for internal use. Try not to inhale the dye powder and please keep away Acid Dye from the child touch.

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