Method of treating a metal substrate
AssigneeXeros Limited
InventorsJohn Edward Steele, Robert Andrew Bird
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Abstract
A method of removing at least a portion of an oxide layer from the surface of a metal substrate comprising exposing the metal substrate to a body of treatment liquor comprising a treatment formulation and a multiplicity of solid particles which comprise or consists of a multiplicity of polymeric particles and wherein said treatment formulation comprises one or more promoters selected from the group consisting of acids, bases and surfactants wherein the method further comprises causing the solid particles and the metal substrate to enter into contacting relative movement.
Claims87
A method of removing at least a portion of an oxide layer from the surface of a metal substrate comprising exposing the metal substrate to a body of treatment liquor comprising a treatment formulation and a multiplicity of solid particles which comprise or consists of a multiplicity of polymeric particles and wherein said treatment formulation comprises one or more promoters selected from the group consisting of acids, bases and surfactants wherein the method further comprises causing the solid particles and the metal substrate to enter into contacting relative movement.
The method according to any one of the preceding claims wherein the one or more promoters comprise at least one organic acid.
The method according to any of the preceding claims wherein the bases have a pKb greater than about −1.7.
The method according to any one of the preceding claims wherein the one or more promoters comprise at least one carboxylic acid moiety.
The method according to any one of the preceding claims wherein the one or more promoters comprise two or more carboxylic acid moieties.
The method according to any one of the preceding claims wherein the one or more promoters comprise at least one citrate moiety.
The method according to any one of the preceding claims wherein the one or more promoters comprise at least one metal chelating agent.
The method according to any one of the preceding claims wherein the one or more promoters comprise at least one surfactant.
The method according to any one of the preceding claims wherein the treatment formulation has a pH between about 1 and about 13.
The method according to any one of the preceding claims wherein the treatment formulation has a pH greater than about 7.
The method according to any one of the preceding claims wherein the treatment formulation is aqueous.
The method according to any one of the preceding claims wherein at least some of the solid particles are buoyant in the treatment formulation.
The method according to any one of the preceding claims wherein the solid particles have an average density of less than about 1.
The method according to any one of the preceding claims wherein the solid particles are in the form of beads.
The method according to any one of the preceding claims wherein the method comprises moving the metal substrate such that its surface is brought into contact with the solid particles.
The method according to any one of the preceding claims wherein the method comprises scouring the surface of the metal substrate with the solid particles.
The method according to any one of the preceding claims wherein the method comprises agitating the solid particles within the treatment liquor.
The method according to any one of the preceding claims wherein the method is carried out using a fluidized bed containing the treatment liquor.
The method according to any one of the preceding claims wherein the treatment liquor contacts the metal surface at a relative velocity of at least 1cm per second.
The method according to any one of the preceding claims wherein the multiplicity of solid particles comprises or consists of a mixture of a multiplicity of polymeric particles and a multiplicity of non-polymeric particles.
The method according to any one of the preceding claims wherein the polymeric particles comprise particles of one or more polar polymers.
The method according to any one of the preceding claims wherein the polymeric particles comprise particles of one or more non-polar polymers.
The method according to any one of the preceding claims wherein the polymeric particles comprise particles of one or more polar polymers and particles of one or more non-polar polymers.
The method according to any one of the preceding claims wherein the polymeric particles comprise particles selected from particles of polyalkenes, polyamides, polyesters, polysiloxanes, polyurethanes or copolymers thereof.
The method according to any one of the preceding claims wherein the polymeric particles comprise particles selected from particles comprising linear, branched or cross-linked polymers.
The method according to any one of the preceding claims wherein the polymeric particles comprise foamed or unfoamed polymers.
The method according to any one of the preceding claims wherein the solid particles are of hollow and/or porous construction.
The method according to any one of the preceding claims wherein the polymeric particles have an average density of from about 0.5 to about 3.5 g/cm3.
The method according to any one of the preceding claims wherein the polymeric particles have a volume in the range of about 5 to about 275 mm3.
The method according to any one of the preceding claims wherein the solid particles are reused one or more times for treatment of metal substrates according to the method of the invention.
The method according to any one of the preceding claims wherein the method comprises a step of recovering the multiplicity of solid particles after treatment of the metal substrate,
The method according to any one of the preceding claims wherein the treatment formulation is substantially free from hydrofluoric acid.
The method according to any one of the preceding claims wherein the treatment formulation comprises one or more components selected from the group consisting of:
- polymers, corrosion inhibitors, builders, dispersants, anti-oxidants, reducing agents, oxidising agents and bleaches.
The method according to any one of the preceding claims wherein the method comprises passivating the metal substrate.
The method according to any one of the preceding claims wherein the method comprises inhibiting the re-growth of an oxide layer on the surface of the metal substrate.
The method according to any one of the preceding claims wherein the method further comprises coating the metal substrate after the removal of at least a portion of the oxide layer.
The method according to any one of the preceding claims wherein the metal substrate comprises a transition metal.
The method according to any one of the preceding claims wherein the metal substrate comprises aluminum.
The method according to any one of the preceding claims wherein the metal substrate is a metal alloy.
The method according to any one of the preceding claims wherein the metal substrate comprises a metal sheet.
The method according to any one of the preceding claims wherein the metal substrate is a can.
A method according to any one of the preceding claims further comprising, prior to the removal of at least a portion of the oxide layer from the metal substrate, cleaning the metal substrate to remove surface contaminants.
The method according to any of claims 56 to 64 wherein the solid particles in the cleaning liquor comprises or consists of a multiplicity of polymeric particles.
The method according to any one of the preceding claims wherein the metal substrate is exposed to the treatment liquor from a period of from 1 second to 4 minutes.
A treatment liquor for removing at least a portion of an oxide layer from the surface of a metal substrate comprising a treatment formulation and a multiplicity of solid particles which comprise or consists of a multiplicity of polymeric particles wherein said treatment formulation comprises one or more promoters selected from the group consisting of acids, bases and surfactants, wherein said treatment formulation comprises:
- i) one or more promoters comprising at least one carboxylic acid moiety;
- ii) one or more promoters comprising at least one surfactant;
- and wherein the particles have a length of from about 0.5 to about 6 mm.
Dependencies are inferred from the claim text.