Dawn Brocco's Life & Design Blog

Kurt Fowler wrote into the Aranknit list yesterday with some research he did on the superwash treatment for yarns. Thank you, Kurt, for researching it and passing it along. I think if we all knew *what exactly* goes into making the goods we use, maybe we wouldn't use/buy all the stuff we do. It certainly is interesting to know how much our momentary *convenience* is costing our earth and water supplies. He has agreed to let me post his post here! Thank you!

Below is Kurt's post, with only minor adjustments made so the links would be clickable in Blogger.

"What follows is a little summary about the process.

The resin process is by far the most common now, which applies a microscopic coating that seals the scales on the surface of the wool fiber. Patents and proprietary secrets make it difficult to uncover just what the heck is going on with superwash wool, but in general broad terms, here is a
typical resin process:

1. Oxidative pretreatment: chlorine and hypochlorous acid pre-treatment bath, hopefully in such a controlled way that it affects only the surface without yellowing and only minor damage to the wool. This step makes the fibre surface charged in such a way that oppositely charged resin molecules are attracted and chemically bonded. (I'll show you my electrons if you show me yours--that sort of thing.) The pre-treatment also raises the surface tension, which makes the resin goo spread evenly during treatment and drying. Finally, pre-treatment adds a low level of shrinkage-resistance.

2. Rinse and neutralization and rinse again: After chlorination, the wool is rinsed, and then the residual acid and chlorine must be deactivated, usually with sodium sulphite, sodium bisulphate, or both. And then the wool is rinsed again, because residual sulphite would be bad for later dyeing.

3. Application of the resin: can you say "cationic amine polyamide-epichlorohydrin resin" fast 3 times? A resin coating process using Hercosett 57 was developed in the 1960s by CSIRO (Commonwealth Scientific and Industrial Research Organisation in Australia) to prevent
shrinking and felting, and it's still widely used. You can see a Before and After resin treatment photo composite at the bottom of
this page. Time marches on, and we are up to Hercosett 125 now.
this page.

4. Application of a softener: it softens, removes unbonded resin, and reduces sticking-together of resin-coated fibres during the drying process.

Most of the process variations appear to apply to the method of pre-treatment -differences in the oxidation agent recipe and method of applying it. However, every recipe and application has at least a little damaging effect on the wool. The improvement of the process has been all
about the improvement of damage control. And the resin coating itself restores some strength.

What is this goo?

Polyamide: a compound characterized by more than one amide group; especially a polymeric amide (as nylon or a polypeptide or a protein)

Epichlorohydrin: a volatile liquid toxic epoxide C3H5ClO having an odor like chloroform, made usually by alkaline hydrolysis of dichlorohydrins, and used chiefly in making epoxy resins

Yummy. What happens to the environment from the making and disposal of superwash yarn? You can do that research yourself, using some of the terms above." Kurt Fowler