We have studied activator-enhanced bleaching action of acidic hydrogen peroxide solution on wool. The commercial product, Prestogen W, and citric acid both prove to be effective. We also studied the interaction between citric acid and hydrogen peroxide using FAB-MS. The natural creamy color of wool can be whitened by oxidative or reductive bleaching agents [ 3,6,7 ] . Oxidative bleaching uses a hydrogen peroxide solution and reductive bleaching uses hydrosulphite, sulphoxylate, or sulphinic acid solutions. For a &dquo;full white&dquo; color, the wool is treated with an oxidative hydrogen peroxide bleach followed by a reductive bleach.Traditionally, wool has been hydrogen peroxide bleached under alkaline conditions, the alkali enhancing the bleaching action by increasing the concentration of perhydroxyl ions:The development of a weakly acidic activated hydrogen peroxide bleaching system permitted effective whitening of wool with the advantages of reduced bleaching time and less fiber damage. The activator, Prestogen W, used in the acid peroxide bleaching system is reported to consist of a mixture of organic salts that form percarboxylic acids [ 2,3 ] . In this study, we report on.a range of carboxylic acids that may activate acid hydrogen peroxide bleaching of wool. In addition, by using FAB-MS, we can investigate the nature of the active bleaching agent and determine whether peracids are being formed.Fast atom bombardment mass spectrometry ( FAB-MS) employs a beam of energetic neutral atoms ( usually Xe) to effect ionization of the sample, which is present in a liquid matrix [I]. The ions so formed are the directed into a mass analyzer where they are separated according to their M / Z (mass to charge) ratio prior to detection. Because FAB is a &dquo;soft&dquo; ionization technique, information regarding molecular mass may be forthcoming.Experimental .The 100% wool fabric (230 g/n-r) was kindly supplied by Parklands, Bradford, U.K., and Prestogen W and Sokalan CP were donated by BASF and Ciba Geigy, respectively. Bleaching treatments were done on a Jefferies Rotadyer laboratory dyeing machine at a wool-to-liquor ratio of 1:20. The standard acidic bleach bath contained 20 ml / hydrogen peroxide (50% w/w) and 1 g/I of a nonionic wetting agent. Various activators were added to the bleach bath at specified concentrations, and the pH was adjusted to 5.5. The bath was either raised from 50°C to 80°C over 15 minutes and maintained for 1 hour, or raised from 50°C to 65 °C and maintained for 2.5 hours.The whiteness indices ( CIE, 1982 ) of the fabrics were the average of five measurements determined on a Macbeth 1500/ Plus color measurement system using a D65 illuminant and a 10° observer...The relative strengths of the fabrics were measured on a Martindale abrasion tester at 65% RH. Fabrics were abraded until two threads were broken. Mass spectrometry involved a Kratos MS50TC double focussing mass spectrometer. The ionization mode was fast atom bombardment using energetic xenon atoms from an Ion-tech gun at 6-8 KeV, 1...

X-ray photoelectron spectroscopy (XPS) is used to investigate the chemical modification of wool fibers arising from gaseous fluorination. Oxidation of the disulphide bond occurs together with a concomitant decrease in felt shrinkage.Felting shrinkage of wool during laundering occurs primarily because the surface cuticular structure of the fiber causes a directional frictional effect [ 7,8 ] . The . . current commercial chlorine/Hercosett process, although highly successful, is now under pressure from environmental legislation, due to the formation of ad-sorbable organohalogens (AOX) during processing. This paper examines the nature of the gaseous fluorination of wool as an alternative shrinkproofing system.Fluorination has a number of important advantages over current chlorination processes: it is a dry process operating at commercially acceptable processing speeds, with organofluorides being undetected by cur. rent AOX testing and probably presenting fewer environmental problems.

The application of uv curing and corona discharge technology to textiles is introduced and discussed, The influence of uv photoreactive monomer on the shrinkage and mechanical properties of corona and nonpretreated 100% wool gabardine fabric is detailed. Machine washability can be achieved at low add-on by incorporating a uv curable silicone into the formulation and a post-cure steam treatment.. Concern over environmental pollution is encouraging the development of low or zero effluent processes for wool. One area of particular concern is the production of machine washable or shrink-resistant wool.Current processes are based on applying preformed polymers from aqueous dispersions (although certain examples can be applied from solvents-silicone DC , 109 ) using an exhaust or pad method [ 13 t. At present, approximately 70% of all wool rendered machine washable is processed in the top form using the (;sIRol tws/Chlorine/Hercosett process [ 2 ] .Chlorination prepares the fabric for the application of the Hercosett polymer (encouraging exhaustion and adhesion ), but also has the additional advantage of partially shrink-proofing the wool [ 13 ] . Although chlorination is both cost effective and suited to this role, it does lead to the presence of adsorbable organohalogeñ ( Ac~x ) in the effluent. Because of the quantity of wool processed this way/the effluent does present a problem [2J.. This paper describes work to develop a dry process for producing shrink-resistant wool by applying a solventless uv -curable polymer system on corona pretreated and non-pretreated wool fabrics.

No abstract

In a preliminary study, the potential for several ultraviolet radiation curing polymer systems as shrinkresist agents for 100% wool fabric has been evalu ated. The impact of these formulations on fabric mechanical properties, and stiffness in particularly was also assessed.