ES299113A1 - Wool fibers sensitized for setting by applying thereto one member of a reducing agent-producing coreactant pair,mechanically finishing and applying the second member of said pair - Google Patents

Abstract

Keratin fibres are presensitized so that they may subsequently be durably set in a desired configuration by treating them with a reducing agent precursor and then treating them with a reducing agent activator. The "reducing agent precursor" is defined as being a compound which forms a reducing agent for keratin fibres upon reaction with another chemical compound, suitable compounds being alkanolamines and other amines, alkali and alkaline earth metal hydroxides, carbonates, borates, bicarbonates and phosphates, aldehydes and ammonia. The "reducing agent activator" is defined as being a compound preferably in gaseous state, which can react with the reducing agent precursor to form a different chemical compound which is a reducing agent for keratin fibres, i.e. is capable of rupturing the disulphide bonds in the keratin fibre, suitable compounds being sulphur dioxide, hydrogen sulphide, mercaptans, mercaptan alcohols, nitrogen oxides, phosphorus-containing gases and nitrosating agents. A swelling agent, e.g. urea, guanidine and its hydrochloride, formamide, N,N,-dimethylformamide, acetamide, thiourea, phenol or lithium chloride, bromide or iodide, or a compound containing more than one hydroxy group and having a molecular weight no greater than 4,000 may be applied to the fabric together with the reducing agent precursor. Fabrics may be impregnated with an aqueous solution of the reducing agent precursor, dried under relaxed conditions, subjected to a finishing operation which is a mechanical operation to which at least one surface of the fabric is treated to impart thereto a more lustrous appearance and/or pleasing hand and may for example comprise rotary pressing, semi-decatising or full decatising, and then treated with the gaseous reducing agent reactor. The presensitized fabric. may subsequently be set in a desired configuration, e.g. creases or pleats, by simple pressing under normal moisture conditions. Fabrics comprising wool fibres alone or in admixture with other keratin fibres, e.g. mohair, alpaca, cashmere, vicuna, guanaco, camels hair or llama, synthetic polyamide, polyester, acrylic, cellulose acetate, viscose rayon or cotton fibres, may be treated, or the fibres may be treated in the form of top, tow, roving, sliver or yarn. The process may be carried out by mounting perforated beam 8 which supports full width lengths of fabric 7 over perforated spindle 6 in reaction chamber 1, preheating it by admitting steam through inlet valve 3 to jacket 2 and withdrawing it through outlet valve 4, feeding ammonia gas from container 22 into heat exchanger 21 and automatic valve 20 into conduits 19 and 14 until a predetermined amount is registered on scale 23 at which time the valve 20 closes and passing the gas into the perforated spindle 6, perforated beam 8 and fabric 7 back into the recirculating system conduct. 13 where it passes via pump 15 through heat exchanger 16 for maintenance of the desired gas temperature. The direction of flow is reversed after a predetermined period of time by switching valve 9 to the position 9' so that the gas is pulled through fabric 7, perforated beam 8 and spindle 9 back into conduit 14. After a predetermined time the apparatus may be vented by closing valve 10, opening inlet valve 37 and venting valve 38 while continuing the cycling operation and then opening valve 10 and closing valves 37 and 38. Liquid sulphur dioxide from container 31 is then passed into heat exchanger 28 which is heated by steam, the liquid immediately vaporizes and is then admitted through valve 27 which automatically closes upon a signal from scale 32 that a predetermined amount of liquid has been utilized. After recirculation the apparatus may again be vented to the atmosphere, additional ammonia circulated, the apparatus vented and the fabric removed.