Inhibition of corrosion of aluminium tubes by toothpastes
AssigneeBeecham Group Limited
InventorCharles J. Taylor
Life of this patent
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Abstract
The tendency of gel toothpastes comprising silica thickeners, such as silica aerogel or precipitated silica, and a fluoride source, such as sodium monofluorophosphate or fluoride, to corrode aluminium tubes can be reduced by incorporating at least 0.01% by weight sodium or potassium hydroxide or carbonate, so that the pH of the toothpaste is at least 8.5.
Claims11
A method of inhibiting corrosion of unlined aluminium tubes by clear or translucent gel toothpastes comprising a fluoride source and a silica thickener, which method comprises the incorporation in the toothpaste of at least 0.01% by weight, based on the weight of toothpaste, of sodium or potassium hydroxide or sodium or potassium carbonate, so that the pH of the toothpaste is at least 8.5.
In a clear or translucent gel toothpaste comprising a fluoride source and a silica thickener packed in a collapsible unlined aluminum tube susceptible to corrosion, the improvement of including in said toothpaste as inhibitor of corrosion of aluminum an amount of sodium or potassium hydroxide or sodium or potassium carbonate sufficient to raise the pH of said toothpaste to at least pH 8.5, said amount being at least 0.01% of the weight of said toothpaste.
Dependencies are inferred from the claim text.