Cleaning compositions containing a colorant stabilized against fading

Abstract From the Canadian patent

An acidic, aqueous cleaning composition comprising a surfactant; up to about 50% of a higher boiling solvent typically an alkyl ether of an alkylene glycol said solvent, introducing impurities into the composition in an amount and of a nature normally chemically incompatible with oxidizable dye chromophores; a dye in an amount to provide a desired tinctorial value, and oxalic acid or a salt thereof in an amount effective to retard fading of the dye. In another aspect of the invention, the oxalic acid incorporated into compositions containing a solvent, a surfactant, and water, and optionally a dye provides a beneficial cleaning result. In yet another aspect of the invention, the oxalic acid …