Daily Archives: February 23, 2015

Will Procion MX dyes work at higher temperatures?

Hi there, I was wondering if fibre reactive dyes will work at higher temperatures? I have trying to dye a rayon blend fabric black without success with procion MX dyes. I even used so much dye and salt that I was having difficulty dissolving it! Anyway I found an alternative dye that works really well but it requires setting at 60 degrees and was wondering what the effect of a high temperature would be on the procion dyes. I would like to use the new black to mix with with procion dyes if possible.

What fiber is the rayon blended with? And what dye are you using, that is working better than Procion dye on rayon? Is it working better just because it is a more intense color, or does it somehow like rayon especially well, or is it also dyeing the other fiber that your rayon is blended with?

60°C, which is 140° Fahrenheit, is a good temperature for a lot of fiber reactive dyes. It’s the ideal temperature for Remazol type fiber reactive dyes. It’s not a bad temperature for Procion MX dyes, though it is warmer than they need.

The effect of warmer temperatures on the Procion MX dyes will be to make them react more quickly—with whatever they are right next to. If you wait until the Procion dyes have soaked well into the fiber you want to dye, this is no problem at all. In fact, extra warmth can be helpful in getting the best possible color intensity from your Procion dyes, if your studio temperature tends to be a little cold, or if you don’t want to wait as long for the dye reaction to take place.

If you apply too much heat immediately after adding the dyes to the fiber (or the fiber to the dyebath), it can speed of the dye-fiber reaction enough to encourage ring dyeing, in which only the very outermost layer of each fiber gets dyed. What happens as a result is that even the slightest amount of wear can degrade the color, as the dyed layer wears off. Ring dyeing is a fault that you want to avoid.

If you apply a lot of heat when the dye is still mostly in the water, most especially if you’ve already added the soda ash or whatever other chemical you’re using to raise the pH, the dye immediately reacts with the water, so then little dye is left to react with the fiber.

Letting the Procion MX dye soak in well before you heat it up will make sure that everything is fine. How much time you should allow depends on how thick the material is. Fifteen minutes is fine if it’s thin and the dye is circulating freely; if the material is thick, or if you have the material tightly crammed into a small container for low water immersion dyeing, you’d do better to allow an hour. See my page, “What is the effect of temperature on fiber reactive dyes?“. Depending on how much heat you need, there are many different ways to supply it.

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Once thin silk takes one color of dye can it be overdyed a darker color?

I recently dyed some pieces of silk and gauze. Once the silk takes one color of dye can it be overdyed a darker color? The colors I got were not what I expected. In one a green color took over the piece. I have tried over dying the green with cobalt and it’s not doing anything. I would love any advice you have to offer.

Thin silk is limited, as you’ve seen, in how many dye molecules it can take up. While thicker fabrics such as a heavy raw silk, or the cotton jersey of t-shirts, can add more color through six or more rounds of dyeing, a very thin sheer fabric, such as chiffon or gauze, may do so through only one or two rounds of dyeing, refusing to change color further when you dye it again.

Physical manipulation of the fabric, as by rough washing, can free up more dye sites in a fabric, but that’s not a good idea with fine silks.

Removing the dye color with a dye discharge chemical, such as thiox, will probably not help, because the dye molecules will still be bound to the fabric even after they have been decolorized by the reducing agent. The hypochlorite in chlorine bleach might chew up enough of the surface of the fabric to reveal more dye sites, if you’re dyeing cotton gauze, but you should never use chlorine bleach on silk, since it is very destructive to protein fibers.

You might be able to add another layer of color if you use an entirely different class of dye which attaches to the molecules of the fabric in a different way. For example, if you have been dyeing your silk with Procion dyes plus soda ash, you might find that dyeing them with acid dye plus an acid, such as vinegar, will allow one more round of color—or if you’ve been using acid dyes, which includes Procion dyes that have been set with an acid rather than soda ash, then you might try dyeing with Procion or another fiber reactive dye, and setting it with soda ash. Definitely a matter of trial and error, no guarantees that it will work, but it is worth experimenting.

Also see my earlier post, “Will a fabric reach a saturation point after which it cannot take any more dye, or any more dye of a given colour?“.

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