Fiber Reactive Dyes
STANDARD FIBERREACTIVE DYES
Although fiber reactive dyes have been around for several decades, they are just now coming into use among silkscreen printers. They are permanent dyes. Unlike inks, they do not rest on the fabric or coat the fabric; they chemically unite with the molecules that make up the fabric. They become part of the fabric and have no tactility.
Standard Fiber Reactive Dyes can be used for any dyeing application. Fabric can be dipped, sprayed, selectively immersed in a dye bath (as in tie dyeing or batik) or painted.
For the purposes of silkscreen, sodium alginate must be used as a thickener. Without a thickener, the water-based dyes will simply pour through the silkscreen. Enough of the sodium alginate must be added to bring the dyes to a consistency comparable to that of silkscreen inks.
Standard Fiber Reactive Dyes can be used, with modifiers, on any natural fabric and on 50% polyester fabrics. Different modifications of the dyes are used for silk, since silk does not react to the dyes in the same way that cotton or linen reacts.
In order for the dyes to penetrate the fabric evenly, it is necessary to wash all the impurities, such as starch and sizing from the fabric's surface. Synthrapol is mixed with the wash water as a detergent to intensify its cleaning. After the dyeing process, synthrapol is used again to remove excess dye from the fabric's surface. Without this cleansing, darker dyes can easily spread to the lighter printed areas. Adding table salt, or sodium sulfate, will discourage dye transfer.
Before dyeing, presoak the fabric in a sodium carbonate solution for about 15 minutes. This will help fix the dyes by adjusting the alkaline value of the water. Alternately, the sodium carbonate can be added directly to the dye mixture.
Once the fabric to be printed has been washed and prepared, the dye, available in powder form, is mixed with warm water. Enough dye must be mixed with the water to create the color hue, or tone, that is desired.
The shelf life of the dyes, once they are mixed with water, is relatively short. Mix as much dye as is needed for no more than a week. The mixed dyes should be refrigerated during storage.
Just before using the dyes, stir in a small quantity of sodium carbonate to activate the chemical reaction. This activation of the dyes is essential in the process. Within hours of this mixing, the dye will begin to lose its strength. When storing mixed dyes, do not add the sodium carbonate until the dye mixture is ready to be used.
Wear a mask when mixing the dyes. The powder is very fine and will slightly irritate the lungs if enough is inhaled.
Urea -- 1 tablespoon per cup
4 teaspoons of dye per cup
Sodium carbonate -- 1 cup per gallon
Sodium sulfate solution [or table salt] -- 1 cup per gallon
It is a good idea to mix a solution of urea and water to soak the fabric. Urea holds the moisture in the fabric and allows a longer time for the dyes to react with the fabric. The fabric must remain wet for the chemical reaction to occur. It is best to keep the fabric wet for a full day before washing. Although the procionic dyes do not need heat setting, the chemical reaction can be hurried by steaming the fabric instead of waiting the several hours that would otherwise be necessary.
Maintain the moisture level during any heat setting.
Washing the fabric after dyeing is best done first in cold water. Subsequently wash with warm water. Washing immediately in warm or hot water may cause unfixed dye to weakly attach and wash out in later washes.
A complete line of colors in procionic dyes is available from Standard Screen Supply. Also, all the additives and modifiers needed to create a procionic dye mixture are available.
The dyes will stain the skin. It is best to work with gloves. However, if the hands are stained, they can be cleaned using industrial-grade hand cleansers.