Title:
|
Chemical Finishing of Wool and Cotton Textile Substrates
|
The chlorine-Hercosett process has been dominant in the wool shrink-proofing
industry for more than 30 years. Hypochlorite breaks the hydrophobic nature of wool
surface; Hercosett (cationic polyamide epichlorhydrin resin) covers wool and prevents
wool from shrinking. From today's modem point of view, however, the chlorineHercosett
process shows a number of drawbacks which make the search for an
ecologically clean alternative worthwhile: poor handle, yellowing of wool, difficulties
in dyeing and most importantly today, environmental impact (rdlease of absorbable
organic halogens- AOX to the effluents). As a result, many researches have been
carried out for Non-AOX rapid oxidation of wool. Potassium peroxomonosulphate
(PMS), hydrogen peroxide and some per acids have been concerned as possible
alternatives, but only little commercial successes.
It was well known that Hercosett will not deposit on the PMS or hydrogen peroxide
treated wool. The key difference. in terms of polymer compatibility between
chlorinated and PMS, hydrogen peroxide treated wool is the surface energy
(wettability). Surface energy has influence on the spreading properties of Hercosett
and wool/polymer interfacial adhesion. Resent researches have shown that this
difference is associated with the removal of a fatty acid (lipid), namely IS-methyleicosanoic
acid (IS-MEA), which is thought to be chemically bound to the surface of
wool fibre by a thio-ester linkage. In common words, chlorination can remove this
fatty acid but PMS and hydrogen peroxide treatments can not.
The wool shrink-proofing research in this thesis is f
|