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US 6,548,468 B1Granted
Solvent-free or solvent-minimized process and composition for cleaning hard surfaces, especially for removing long-dried paint and carbonaceous soils from aluminum engine parts
AssigneeHenkel Corporation
InventorsMervet S. Boulos, Craig S. Caldwell
Life of this patent
Estimating the term…
Abstract
An aqueous based cleaner containing at least inorganic alkalinizing agents and surfactants is capable of removing long dried paint and thick carbonaceous deposits from used aircraft engines, sometimes without using organic solvents at all and always without using more than a few % of such solvent, thereby greatly reducing pollution potential from this difficult cleaning operation. A preferred cleaner also includes a hydrotroping agent, and the cleaner may also contain corrosion inhibitor, sequestering agent for hard water cations, and other materials.
Claims14
A process for removing from a metal surface:
- at least 50% of an adherent carbonaceous deposit that is at least 0.2 mm thick and has been formed on at least one of:
- said metal surface;
- and
- paint that is in contact on one side with said metal surface by contact between:
- at least one of said metal surface and said paint and
- at least one of:
- hot gaseous products of combustion emitted from an internal combustion engine;
- and
- fuel for, lubricating materials for, or both fuel and lubricating materials for, an internal combustion engine;
- and
- any paint that is in contact with said metal surface at the beginning of said process, said process comprising at least one operation of contacting at least one of said metal surface, said paint in contact with said metal surface at the beginning of the process, and said carbonaceous deposit with an aqueous liquid cleaning composition that comprises water and the following components:
- (A) a component of inorganic alkalinizing agent selected from the group consisting of hydroxides, salts of polyfunctional inorganic acids, and mixtures thereof;
- and
- (B) a component of surfactant molecules that are not inorganic alkalinizing agents, at least part of said surfactant molecules being nonionic surfactants;
- and does not comprise more than about 6% of organic solvent, said operation of contacting being continued for an interval of time and then discontinued and, optionally, being followed by an operation of rinsing said metal surface with pressurized water.
12 more elements
A process for removing from a metal surface:
- at least 50% of an adherent carbonaceous deposit that is at least 0.2 mm thick and has been formed on at least one of:
- said metal surface;
- and
- paint that is in contact on one side with said metal surface by contact between:
- at least one of said metal surface and said paint and
- at least one of:
- hot gaseous products of combustion emitted from an internal combustion engine;
- and
- fuel for, lubricating materials for, or both fuel and lubricating materials for, an internal combustion engine;
- and
- any paint that is in contact with said metal surface at the beginning of said process, said process comprising at least one operation of contacting at least one of said metal surface, said paint in contact with said metal surface at the beginning of the process, and said carbonaceous deposit with an aqueous liquid cleaning composition that has been made by mixing with a first mass of water at least the following masses of the following substances:
- (A) a second mass of inorganic alkalinizing agent selected from the group consisting of hydroxides, salts of polyfunctional inorganic acids, and mixtures thereof;
- and
- (B) a third mass of surfactant molecules that are not inorganic alkalinizing agents, at least part of said surfactant molecules being nonionic surfactants,
- said aqueous liquid cleaning composition not comprising more than about 6% of organic solvent, said operation of contacting being continued for an interval of time and then discontinued and, optionally, being followed by an operation of rinsing said metal surface with pressurized water.
12 more elements
Dependencies are inferred from the claim text.