Dyeing of clothing materials.
The binding of the dye with the colored substrate occurs through chemical and physical processes.
As a result of choosing the right dye and proper dyeing operations, a nice one is obtained, vivid color of the material, resistant to selected washing agents and to long-lasting effects of light. Natural fibers – vegetable (Cotton, len) and animals (wool, silk) – is dyed with both dyes from the group of dyes directly, to which they belong: direct, basic and acidic, as well as dyes produced on dyed material - i.e.. mortar, ladle and ice cream. Artificial fibers should be dyed with special dyes, adapted to the properties of the substrate.
Most commercially available dyes, intended for home use, are dyes that dye directly. The recipe for use is indicated on the packaging. The dye is dosed in relation to the weight of the dry fabric to be dyed. Please note, that the fabric pulls the dye out of the bath, so when you dye several consecutive pieces in the same bath, you get brighter and brighter colors. To obtain the same intense dyeing of several sections of the fabric, they should be dyed at the same time, preparing a sufficiently large volume of bath.
Marking the characteristics of the dye. Usually in the name of the dye, in addition to the color mentioned (red, blue, etc.), there are adjective forms and strings of capital letters. Adjectives define a group, to which the dye belongs: direct, acidic, acidochromic – these are self-explanatory. Importance of others, frequently encountered, adjectives is as follows: folate – acidic, helionic -direct, neolanic – acidochromic, the root "antren" in the adjective (indantrenowy, helanthrenic, training) – means vat dye, anthracene derivative. Litery G, R, B are the shade of the color: G – greenish, R – reddish, B – bluish, repeating a letter means greater depth of shade. The letter L stands for high lightfastness, and repetition (LL) – very high resistance to light. Other letters indicate the factory type of dye. Dyeing with vat dyes, giving permanent dyeing of plant fibers, can be performed as follows: on 100 Prepare a bath for 1 g of fabric by rubbing it first 4 g of dye to paste with 40 cm3 40 – % NaOH solution, (40 g NaOH + 60 cm3 of water), then this paste is transferred to 4 dm3 of water, containing 20 g of sodium sulfite or hydrosulfite, mixes and heats to 60 – 70° C within 20 – 25 min. The fabric should be dyed through 5 min in a bath cooled to room temperature, followed by 5 min in a bath heated to 50 ° C.
After the fabric has drained from the bath, it must be dried at room temperature. The intensity of the dyeing can be adjusted by reducing or increasing the amount of dye.
Direct dyes. They dye plant fibers in a neutral water bath with the addition of table salt or sodium sulphate to facilitate the removal of the dye from the bath.
Basic dyes. They dye animal fibers in a neutral or slightly acid bath directly, and plant fibers after saturating them with a solution of tannin and antimony compounds (antimonyl potassium tartrate, called an emetic). Other solutions can be used instead of tannins, containing natural tannins, e.g.. oak bark extract, jelly extract or synthetic tannins, called katanols.
Acid dyes. They only dye animal fibers in acid baths. After staining, an additional bath in chromium salt solutions is desirable (sulfate, chromium chloride, chromium-potassium alum). It improves the depth of color and increases the durability of dyeing. A variation of these dyes are acid-chromic dyes (neolanowe, containing chromium compounds, thus not requiring an additional bath in chromium salts).
Mordant dyes. They are used both for plant fibers, as well as animals. They color permanently, however, the dyeing process is somewhat troublesome. The sparingly soluble color compound is formed on the fiber with a saturated salt solution of a trivalent metal, the most common aluminum, chromium or iron. These color compounds are called lacquers, hence the sometimes used name: lacquer dyes. The most commonly used mortars are aluminum or chromium sulphates or suitable alum. A typical mordant dye is alizarin and its related compounds.
Vat dyes. It is used almost exclusively for dyeing plant fibers, because alkaline solutions are harmful to animal fibers. The dyes are very durable. In their colored form, they are sparingly soluble in water. Under the action of reducing agents in an alkaline environment, they transform into colorless or weakly colored soluble compounds. The precipitation of the dye occurs under the action of oxygen in the air, when drying the fabric at room temperature. The action of hot steam on the dyed fabric increases the durability of dyeing. Printing a pattern on the dyed fabric with a paste containing a reducing agent and a thickener gives a local reduction. Reduced, water-soluble dye, removes by washing quickly. The result is a white pattern on a colored background (busy wywabiany).
Ice dyes. They stain plant and animal fibers. The fabric is saturated with a colorless solution of the compound, which is one of the reactants, and then passed through a second bath, in which the synthesis of the dye takes place. Because the bath ingredients are unstable and even decompose at room temperature, it is cooled down with pieces of ice floating in it – hence the name of the dyes. Printing one of the components on the fabric in a compact form and passing the fabric through a second bath gives a colorful pattern on a white background (called printing).
Dyes for artificial fibers. In addition to the aforementioned special dyes, it is also possible to use direct dyes for dyeing synthetic fibers, while observing the following instructions: plastics derived from cellulose (whip cellulozy, cellulose acetate, acetate silk, viscose fibers, cellophane, celluloid) can be dyed with dyes used to dye vegetable fibers – their basic ingredient is also cellulose, while polyamide plastics (polyamide, stylon, nylon, kapron), casein (gala- lit) and melamine – dyes used to dye animal fibers, also because of the similarities in construction.