Rinse aid agents are applied in automatic car washes to promote the drying of wet surfaces after a vehicle is cleaned. Such compositions typically contain a hydrophobic substance, a cationic emulsifier (e.g., a dialkyl dimethyl quaternary ammonium compound, or imidazoline quaternary surfactant), solvents (usually glycol ethers and/or alcohols) and, optionally, coemulsifiers (mostly nonionic or amphoteric surfactants such as alcohol ethoxylates, amine ethoxylates, betaines, etc.). During washing of a vehicle, the use of surface-active agents in the washing water results in the formation of a continuous, firmly adhering film of water on the vehicle surface. This film has to be removed to promote drying and to avoid the formation of spots or streaks due to the presence of salts and other impurities in the water. To achieve this, surface-active quaternary ammonium compounds and hydrophobes are added to the water in the rinsing phase. Because of the adsorption of the cationic surfactant and the hydrophobe on the paint surface, the water film is opened up, and the drops of water can then easily be removed by means of a blower.
Many of the ingredients typically used in rinse aids have undesirable environmental and performance characteristics, such as poor biodegradability or even toxicity, unpleasant smell, flammability, and high volatile organic compound (VOC) content. In addition, these compositions are often in the form of emulsions that may go through a viscous gel phase upon dilution. This makes them difficult to apply in automated carwash operations since they may plug spray nozzles and interfere with the proper operation of metering pumps.
US application Ser. Nos 2005/0014672 is directed to a rinse aid additive and to rinse aid compositions containing the additive. The additive includes: an amidoamine quaternary ammonium component derived from a non-animal source; a first primary amine ethoxylate derived from a non-animal source; and a second primary amine ethoxylate derived from an animal source.
U.S. Pat. No. 6,235,914, U.S. Pat. No. 6,376,455 and U.S. Pat. No. 6,458,343 relate to quaternary ammonium compounds and formulations thereof that are useful as cleaning compositions, antistatic compounds, paper debonders, fabric softeners, hair conditioners, skin conditioners, paper deinking and ink floatation agents, asphalt emulsion agents, corrosion inhibitor agents, ore floatation agents, pesticide emulsion agents, car drying aid sprays, drilling fluid additives, and the like.
U.S. Pat. No. 5,703,029 is directed to a water-dilutable car drybright compositions which have a strong hydrophobicizing action and which are used in rinsing liquids at carwash installations. The disclosed compositions contain ester quats which are the reaction products of alkanolamines and fatty acids, a fatty amine coemulsifier and a glycol ether solvent.
U.S. Pat. No. 6,255,274 relates to soil release polymers in detergents, cleaning agents and fabric softeners. The latter may contain ester quats which are the reaction products of alkanolamines and fatty acids and further quaternized with customary alkylating or hydroxyalkylating agents. Triethanolamine and methyl diethanolamine type ester quaternaries are particularly preferred.
EP 1 323 817 B1 discloses cationic preparations for cleaning hard surfaces, that contain esterquats with acyl groups derived from unsaturated C8-C22 fatty acids with iodine values of 100 to 150 as cationic surfactants.
EP 1 840 197 A1 relates to a composition for rinsing and drying vehicles comprising at least one addition salt of an ester amine. The comparative examples disclose compositions comprising a triethanolamine oleic acid ester quat, a hydrophobe, an ethoxylated amine coemulsifier and a butyl glycol solvent.
U.S. Pat. No. 5,827,451 discloses isotropic oil-in water microemulsions containing an oil component of a fatty acid, fatty alcohol or ester thereof; a quaternary ammonium component; an ether component; and water. The microemulsions may be used to form hydrophobic films on hard surfaces, rendering them useful in carwashes.
EP 0 421 146 discloses biodegradable compositions that can be used as drying agents for paint surfaces. The compositions contain a cationic surfactant, an emulsifier, a solvent and an oily component.
U.S. Pat. No. 5,391,325 discloses compositions for rinsing and drying vehicles comprising a cationic emulsifier, a fatty acid ester of an alcohol having 1 to 5 carbon atoms and a solubilizer, which can be a glycol ether solvent or an amine oxide.
Although the prior art discloses compositions that are useful as rinse aids, known compositions containing biodegradable emulsifiers usually provide emulsions of inferior stability and are less efficient as rinse aids. Therefore, there is still a need for rinse aid compositions with biodegradable components that form stable emulsions and impart hard surfaces with a durable hydrophobic coating that promotes short drying times at low use concentrations. In addition, it would be highly desirable if these compositions do not form gels during dilution.