PROCEDIMIENTO DE ELIMINACIËN DE AGENTES DE DISPERSIËN-MOJADURA DE UN MATERIAL REVESTIDO O TRATADO CON UN MATERIAL POLIMERO DE UNA SOLUCIËN COLOIDAL QUE CONTENGA DICHO AGENTE

摘要

Dispersing/wetting agents are removed from glass fabrics coated with a perfluorocarbon polymer, e.g. polytetrafluoroethylene, from a colloidal solution containing such dispersing/wetting agents by subjecting the coated fabrics to the action of a solvent for such agents for extraction thereof. The colloidal solution used for the coating may be an aqueous dispersion or an organosol. The dispersing/wetting agents may be non-ionic long chain ethers or alcohols or salts of long chain sulphonated acids and suitable solvents are aromatic hydrocarbons, chlorinated hydrocarbons, ethers and ketones, e.g. the monomethyl ether of ethylene glycol. The dispersion medium may first be removed by heating the coated fabrics at a temperature and for a sufficient time to effect volatilization and further coatings may then be applied, the solvent extraction taking place after each coating or after the last coating. After the solvent extraction plies of the coated fabrics may be heated under pressure to sinter and coalesce the polymer. The process is applicable to the manufacture of polytetrafluoroethylene/glassfibre laminates which are provided on one or more surfaces with a layer of copper for use in the electrical and electronic industries for the production of printed circuits by appropriate etching of the copper.ALSO:Dispersing/wetting agents are removed from glass fibrous materials coated with a perfluoro carbon polymer, e.g. polytetrafluoroethylene, from a colloidal solution containing such dispersing/wetting agents by subjecting the coated materials to the action of a solvent for such agents for extraction thereof. The colloidal solution used for the coating may be an aqueous dispersion or an organosol. The dispersing/wetting agents may be non-ionic long chain ethers or alcohols or salts of long chain sulphonated acids and suitable solvents are aromatic hydrocarbons, chlorinated hydrocarbons, ethers and ketanes, e.g. the monomethyl ether of ethylene glycol. The dispersion medium may first be removed by heating the coated materials at a temperature and for sufficient time to effect volatilization and further coatings may then be applied, the solvent extraction taking place after each coating or after the last coating. After the solvent extraction the coated materials may be subjected to the action of heat and pressure to sinter and coalesce the polymer.