Hartwig Prof. Dr. Höcker

ZERO-AOX SHRINKPROOFING TREATMENT FOR WOOL TOP AND FABRIC. PART I : GLOW DISCHARGE TREATMENT

The glow discharge treatment of wool in nonpolymerizing gases like air, oxygen, and nitrogen is presented as a new zero-AOX pretreatment for shrinkproofing wool top and fabric. Modification of the wool fibers is restricted to the outer 30-50 nm, and consists of plasma etching and surface oxidation. The former is responsible for the abrasion of the fatty acid layer from the cuticle and parts of the exocuticle-A; the latter introduces new anionic groups, i.e., sulphonate and carboxylate functions. Car boxyl groups derive from a backbone oxidation of the protein chains in the cuticle cells. Sulphonate groups are generated by oxidation of disulphide functions. Surface modification applicable to both wool top and fabric results in an increased hydro philicity of the fiber surface and has an excellent shrinkproofing effect in combination with a new shrinkproofing resin.

ZERO-AOX SHRINKPROOFING TREATMENT FOR WOOL TOP AND FABRIC. PART II : COLLAGEN RESIN APPLICATION

The halogen-free shrinkproofing resin presented in this work is based on the natural protein collagen and a crosslinking agent, which provides a covalent linkage between the wool and the resin (collagen). Glycidylacrylate and the trifunctional epoxide Araldit PT 810 are applied as crosslinkers. Almost complete shrink resistance of wool fabric and top is achieved using the collagen / Araldit resin with plasma pretreated material. In combination with the oxidative plasma treatment described in Part I, the additive collagen treatment appears to be an effective substitute for the chlorine /Hercosett process.

Typical Fracture Appearance of Broken Wool Fibers After Simulated Sunlight Irradiation

After determining the wet bundle strength of sunlight irradiated wool, the broken fiber ends are evaluated optically by electron microscope. Three different modes of fiber fracture are identified. Due to the breakage morphology, we assume that the histological wool components are damaged to a different extent as a function of ir radiation time. Thus, the frequency of the breakage modes may serve to indicate the stage of fiber damage. We suppose that the initial step of photodamage is the pho tooxidation of the internal lipids, because they are obviously modified after a very short time of irradiation, while the keratin components are visibly intact. After long irradiation periods, the fibrous structure of the keratin fibrils is no longer recognizable.