|Title:|| PROCESS FOR INCREASING WATER REPELLENCY OF COTTON CLOTH|
|Abstract:||A manufactured material and a process for making the material is disclosed. The manufactured material is a hydrogen containing substance having a fluorinated surface and in which hydrogen atoms, which may be present in hydroxyl radicals attached to a carbon atom chain, have been replaced in the surface of the material by fluorine atoms or radicals, and with such fluorinated surface of the material containing at least about 2 micrograms of such fluorine per cm.sup.2 of surface area. The process for making such a material includes the steps of selecting a substrate containing hydrogen atoms which may be present in hydroxyl radicals attached to a carbon atom chain, selecting a gas containing fluorine atoms or radicals, placing the selected substrate between electrodes in a flowing atmosphere of the selected gas at subatmospheric pressure, and subjecting the substrate to an electrodeless discharge of at least about 0.2 KWH/yard.sup.2 to chemically activate both the surface of the substrate and the gas, and exchange the fluorine atoms or radicals for surface hydrogen atoms or radicals to produce a material with a surface, which compared to the substrate before this process treatment, is more water repellent (without sealing pores), is more corrosion and soil resistant, more chemically inert, and more like the relatively expensive polytetrafluoro-ethylene. When the substrate is a material having a relatively inert surface, such as polyethylene, the process is disclosed as including an initial treatment step that involves ion bombardment of the substrate in helium gas to activate the surface before the surface is treated in the fluorine containing gas.|
|Inventor(s):|| Manion; Jean P. (Milwaukee, WI), Davies; Daniel J. (Mukwonago, WI) |
|Assignee:|| Allis-Chalmers Manufacturing Company (Milwaukee, WI) |
|Filing Date:||Aug 01, 1969|
|Claims:||1. A process for increasing the water repellency of cotton cloth including the steps of: selecting a treatment gas from a group consisting of CF.sub.4, C.sub.2 F.sub.6, C.sub.3 F.sub.8, C.sub.4 F.sub.8(c), CHF.sub.3 and SF.sub.6 ; arranging the cotton cloth between electrodes separated by an insulating material; flowing an atmosphere of the gas between the electrodes and in contact with the cloth at the rate of approximately 5 millimoles per minute under a pressure of between 0.5 and 50 Torr; and applying electric power to the electrodes to expose a unit area of the cotton cloth to an electrodeless discharge of electrical energy of about 0.2 KWH per square yard of cloth. |
2. A process according to claim 1 in which said power is applied to subject the substrate in the flowing atmosphere of gas to said discharge until the hydrogen replaced by fluorine provides in said surface at least about 2 micrograms of such fluorine per cm.sup.2 of surface area.
3. A process according to claim 1 in which said power is applied to subject the substrate in the flowing atmosphere of gas to said discharge for a period of from 3 to 400 seconds.