Problems with discoloration of polyester in industrial dyeing
Name: Larry
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Country or region: USA
Message: I am a partner in a laundry chemical co that sells/services linen plants. I have a large linen plant that processes white spun polyester. They require steam injection to acheive ideal wash temperatures. The spun polyester has taken on a light yellow cast. My theory is that the boiler chemical(s) designed to flash off in the boiler header have escaped into the wash liquor. The reaction between the optical brightener in the spun polyester and the boiler chemicals have created a reactive dye; thus the discoloration. I am looking for confirmation on my theory. If this is not your area of expertice, perhaps you can direct me.
My area of expertise is only hand dyeing, and I have no links to help in industrial dyeing.
Your hypothesis that some boiler chemical is the cause of the problem seems sound to me. We know that hypochlorite bleach, for example, will permanently stain polyester a dull yellowish color. So, presumably, will any strong chlorine-based bleaching chemical.
However, there is zero chance that this boiler chemical might somehow be forming a reactive dye; a reactive dye is a very specific and complicated sort of chemical, which is not apt to be formed from random reagents. If it were a reactive dye, it would not react with polyester. (See "About Fiber Reactive Dyes".)
What you have here is a contaminant that, although it is not a dye, is reacting with either the polyester or the optical brightener in an undesirable fashion. What happens if you omit the boiler chemical that you most suspect? Is there a ready alternative?
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Posted: Tuesday - April 16, 2013 at 07:40 AM
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