Improvements in or relating to chromium coordination complexes of saturated perfluoromonocarboxylic acids and articles coated therewith

摘要

The invention comprises chromium co-ordination complexes formed by reacting chromyl chloride with saturated perfluoro-monocarboxylic acids of 4-10 carbon atoms per molecule in an inert anhydrous solvent and in the presence of a reducing agent and the hydrolysed and ammoniated derivatives of these complexes. Cyclic and non-cyclic acids may be used, those specified being perfluoro-cyclohexane carboxylic acid and perfluorocyclohexane acetic acid. Absolute ethanol is a specified reducing agent and carbon tetrachloride a specified solvent. Preferably the chromyl chloride and acid are reacted in a 2 to 1 molar ratio. On hydrolysis, e.g. with water, or treatment with ammonia, the chlorine atoms of the complex are respectively converted to hydroxyl or amino groups. In examples: (1) n-heptafluorobutyric acid; (2) n-undecafluorocaproic acid; and (3) perfluorocyclohexane carboxylic acid are treated in refluxing ethanol and carbon tetrachloride with chromyl chloride and the products recovered on removal of the solvents. The products provide water-proof coatings, c.f. Groups III and VIII. The perfluorocarboxylic acids used as starting material are made by hydrolysing the corresponding acid fluorides obtained by electrolysing a solution of anhydrous liquid hydrogen fluoride containing a dissolved hydrocarbon monocarboxylic acid, c.f. Specification 686,678.ALSO:Glass filaments and fibres are treated with solutions in water or organic solvents of chromium co-ordination complexes of saturated perfluoro-monocarboxylic acids of 4-10 carbon atoms per molecule made by reacting chromyl chloride with the saturated acid in an inert anhydrous solvent and in the presence of a reducing agent or with similar solutions of the hydrolyzed or ammoniated derivatives of the complexes. They provide an anti-abrasive layer. Cyclic and non-cyclic acids may be used for complex formation e.g. u-heptafluorobutyric, n-undecafluorocaproic, perfluorocyclohexanecarboxylic and perfluorocyclohexane acetic acids. The hydrolyzed and ammoniated derivatives are obtained by treating with water or ammonia respectively. Treatment may be effected with a solution of the original complex in a non-aqueous solvent e.g. acetone or isoproparol followed by hydrolysis and oven drying; an aqueous solution of the original complex is applied followed by heat treatment; an aqueous solution of the original complex is boiled to hydrolyze the complex and applied to the material which is then dried in an oven at 60-100 DEG C. a neutralizing agent e.g. sodium bicarbonate or a tertiary amine, may be present or an anhydrous alcoholic e.g. isopropanolic, solution of the original complex is treated with ammonium, the solution diluted or preferably filtered to remove precipitated ammonium chloride and applied to the material which is then dried in an oven.ALSO:Water-proof and anti-abrasive coating compositions comprise aqueous or non-aqueous solutions of chromium co-ordination complexes made by reacting chromyl chloride with a saturated perfluorocarbon carboxylic acid of 4-10 carbon atoms per molecule in an inert anhydrous solvent and in the presence of a reducing agent or similar solutions of the hydrolysed or ammoniated derivatives of the said complexes. Cyclic and non-cyclic acids may be used for complex formation, e.g. n-hepta-fluorobutyric, n-undecafluorocaproic, perfluorocyclohexane carboxylic and perfluorocyclohexane acetic acids. Acetone and isopropanol are specified non-aqueous solvents. Neutralizing agents, e.g. sodium bicarbonate or a tertiary amine, may be present. The coating may be applied to hydrophilic-surfaces such as glass, wood or metals, e.g. aluminium.