EP1181107A2 - Korrosionsbeständige verschweissbare metall-substrate und verfahren zu ihrer herstellung - Google Patents
Korrosionsbeständige verschweissbare metall-substrate und verfahren zu ihrer herstellungInfo
- Publication number
- EP1181107A2 EP1181107A2 EP00932216A EP00932216A EP1181107A2 EP 1181107 A2 EP1181107 A2 EP 1181107A2 EP 00932216 A EP00932216 A EP 00932216A EP 00932216 A EP00932216 A EP 00932216A EP 1181107 A2 EP1181107 A2 EP 1181107A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- metal substrate
- coated metal
- substrate according
- weldable
- binder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/50—Multilayers
- B05D7/52—Two layers
- B05D7/54—No clear coat specified
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/226—Non-corrosive coatings; Primers applied before welding
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/24—Electrically-conducting paints
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/34—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
Definitions
- This invention relates generally to weldable, corrosion- resistant coated metal substrates and, more particularly, to metal substrates having chrome-free coatings thereon which inhibit corrosion and facilitate forming and welding of the metal substrate.
- Weldable coatings containing an electrically conductive material, such as zinc, are often used to provide an electroconductive layer on metal substrates.
- Zinc-rich weldable coatings can be applied directly to ferrous metal surfaces or over ferrous metal which has been treated with a chromium-containing solution.
- U. S. Patent No. 4,346,143 discloses a process for providing corrosion protection to ferrous metal substrates comprising etching the surface of the substrate with nitric acid followed by applying a zinc-rich coating including a binder material to the etched surface .
- 4,157,924 and 4,186,036 disclose a weldable coating for metallic substrates which contains an epoxy or phenoxy resin, electroconductive pigment such as zinc and a diluent such as glycol ether.
- the substrate can be pretreated with a pulverulent metal-free composition containing chromate and/or phosphate ions.
- European Patent Application No. 0157392 discloses an anti-corrosive primer for metal phosphate- or chromate-treated steel which consists of a mixture of 70 to 95 weight percent zinc, aluminum, a gliding agent and a binding agent .
- U. S. Patent No. 3,687,739 discloses a weldable composite coating comprising (1) an undercoating of pulverulent metal and a hexavalent chromium-containing liquid composition and (2) a top coat comprising a particulate, electrically conductive pigment and a binder material.
- chromium-containing coatings provide excellent corrosion protection, particularly under zinc-rich coatings, they are toxic and present waste disposal problems. Therefore, there is a need for chromium-free treatment solutions for treating metal substrates prior to the application of a weldable coating.
- the treatment solution should provide corrosion resistance and maintain substrate electroconductivity for welding.
- One aspect of the present invention is a weldable, coated metal substrate comprising: (a) a metal substrate; (b) a pretreatment composition comprising a Group IIIB or IVB metal compound or mixtures thereof deposited upon at least a portion of a surface of the metal substrate; and (c) a weldable coating comprising an electroconductive pigment dispersed throughout a binder deposited upon at least a portion of the pretreatment composition.
- Another aspect of the present invention is a method for preparing a weldable, coated metal substrate, comprising the steps of: (a) treating a surface of a metal substrate with a pretreatment composition comprising a Group IIIB or IVB metal compound or mixtures thereof to form a substrate having a pretreated surface; and (b) applying a weldable coating composition to the pretreated surface to form a weldable, coated metal substrate, the weldable coating composition comprising an electroconductive pigment and a binder.
- the metal substrates used in the practice of the present invention include ferrous metals, non-ferrous metals and combinations thereof.
- Suitable ferrous metals include iron, steel, and alloys thereof.
- Non-limiting examples of useful steel materials include cold rolled steel, galvanized (zinc coated) steel, electrogalvanized steel, stainless steel, pickled steel, zinc-iron alloy such as GALVANNEAL, and combinations thereof.
- Useful non-ferrous metals include aluminum, zinc, magnesium and alloys thereof. Combinations or composites of ferrous and non-ferrous metals can also be used such as GALVALUME and GALFAN zinc-aluminum alloys.
- the shape of the metal substrate can be in the form of a sheet, plate, bar, rod or any shape desired.
- the shape of the metal substrate is an elongated strip wound about a spool in the form of a coil.
- the thickness of the strip preferably ranges from about 0.254 to about 3.18 millimeters (mm) (about 10 to about 125 mils) , and more preferably about 0.3 mm, although the thickness can be greater or less, as desired.
- the width of the strip generally ranges from about 30.5 to about 183 centimeters (about 12 to about 72 inches), although the width can vary depending upon its intended use.
- the surface of the metal substrate can be cleaned by physical or chemical means, such as mechanically abrading the surface or cleaning/degreasing with commercially available alkaline or acidic cleaning agents which are well know to those skilled in the art, such as sodium metasilicate and sodium hydroxide.
- alkaline or acidic cleaning agents which are well know to those skilled in the art, such as sodium metasilicate and sodium hydroxide.
- a non-limiting example of a preferred cleaning agent is CHEMKLEEN 1633, an alkaline-based cleaner commercially available from PPG Pretreatment and Specialty Products of Troy, Michigan.
- the metal substrate is usually rinsed with water in order to remove any residue.
- the metal substrate can be air dried using an air knife, by flashing off the water by brief exposure of the substrate to a high temperature or by passing the substrate between squeegee rolls .
- a pretreatment coating composition is deposited upon at least a portion of the outer surface of the metal substrate.
- the entire outer surface of the metal substrate is treated with the pretreatment composition.
- the pretreatment composition facilitates adhesion of the subsequently applied weldable coating composition to the metal substrate.
- the pretreatment should be sufficiently thin and/or deformable to permit the heat and force applied to the weldable coating by the welding tool to drive at least a portion of the electroconductive pigment therein through the pretreatment coating to contact or essentially contact the metal substrate and provide an electrically conductive path to permit welding of the coated substrate.
- essentially contact means that the electrical resistance provided by the pretreatment coating is less than about 1 ohm.
- the thickness of the pretreatment film can vary, but is generally less than about 1 micrometer, preferably ranges from about 1 to about 500 nanometers, and more preferably is about 10 to about 300 nanometers.
- the pretreatment composition comprises one or more Group IIIB or IVB element-containing compounds or mixtures thereof solubulized or dispersed in a carrier medium typically an aqueous medium.
- the Group IIIB and IVB elements are defined by the CAS Periodic Table of the Elements as shown, for example, in the Handbook of Chemistry and Physics, (60th Ed. 1980) .
- Transition metal compounds and rare earth metal compounds are compounds of zirconium, titanium, hafnium, yttrium and cerium and mixtures thereof.
- Typical zirconium compounds may be selected from hexafluorozirconic acid, alkali metal and ammonium salts thereof, ammonium zirconium carbonate, zirconyl nitrate, zirconium carboxylates and zirconium hydroxy carboxylates such as hydrofluorozirconic acid, zirconium acetate, zirconium oxalate, ammonium zirconium glycolate, ammonium zirconium lactate, ammonium zirconium citrate, and mixtures thereof.
- Hexafluorozirconic acid is preferred.
- An example of the yttrium compound is yttrium nitrate.
- titanium compound is fluorotitanic acid and its salts.
- hafnium compound is hafnium nitrate.
- cerium compound is cerous nitrate.
- the Group IIIB or IVB metal compounds are in the form of metal salts or acids which are water soluble .
- the Group IIIB or IVB metal compound is typically present in the carrier medium in an amount of 10 to 5000 ppm metal, preferably 100 to 300 ppm metal.
- the pretreatment composition carrier may contain a film forming resin.
- Suitable resins include reaction products of one or more alkanolamines and an epoxy- functional material containing at least two epoxy groups, such as those disclosed in U. S. Patent No. 5,653,823.
- such resins contain beta hydroxy ester, imide, or sulfide functionality, incorporated by using dimethylolpropionic acid, phthalimide, or mercaptoglycerine as an additional reactant in the preparation of the resin.
- the reaction product is that of the diglycidyl ether of Bisphenol A (commercially available from Shell Chemical Company as EPON 880), dimethylol propionic acid, and diethanolamine in a 0.6 to 5.0:0.05 to 5.5:1 mole ratio.
- suitable resins include water soluble and water dispersible polyacrylic acids as disclosed in U. S. Patent Nos. 3,912,548 and 5,328,525; phenol-formaldehyde resins as described in U. S. Patent No. 5,662,746, incorporated herein by reference; water soluble polyamides such as those disclosed in WO 95/33869; copolymers of maleic or acrylic acid with allyl ether as described in Canadian Patent Application No.
- the film forming resin is present in the pretreatment coating composition in an amount of 0.005% to 30% based on the total weight of the pretreatment composition, and the Group IIIB or IVB metal compound is present in an amount of 10 to 5000, preferably 100 to 1000, ppm metal based on total weight of the pretreatment composition.
- the weight ratio of the resin to Group IIIB or IVB metal or metal compound is from 2.0 to 10.0, preferably 3.0 to 5.0, based on metal.
- the pretreatment coating composition can further comprise surfactants that function as aids to improve wetting of the substrate.
- the surfactant materials are present in an amount of less than about 2 weight percent on a basis of total weight of the pretreatment coating composition.
- Other optional materials in the carrier medium include surfactants that function as defoamers or substrate wetting agents.
- the pretreatment coating composition is essentially free of chromium-containing materials, i.e., contains less than about 2 weight percent of chromium- containing materials (expressed as Cr0 3 ) , and more preferably less than about 0.05 weight percent of chromium-containing materials.
- chromium-containing materials examples include chromic acid, chromium trioxide, chromic acid anhydride, dichromate salts such as ammonium dichromate, sodium dichromate, potassium dichromate, and calcium, barium, magnesium, zinc, cadmium and strontium dichromate.
- the pretreatment coating composition is free of chromium-containing materials.
- the pretreatment coating composition is applied to the surface of the metal substrate by any conventional application technique, such as spraying, immersion or roll coating in a batch or continuous process.
- the temperature of the pretreatment coating composition at application is typically about 10°C to about 85°C, and preferably about 15°C to about 60°C.
- the pH of the preferred pretreatment coating composition at application generally ranges from about 2.0 to about 5.5, and is preferably about 3.5 to about 5.5.
- the pH of the medium may be adjusted using mineral acids such as hydrofluoric acid, fluoroboric acid, phosphoric acid, and the like, including mixtures thereof; organic acids such as lactic acid, acetic acid, citric acid, sulfamic acid, or mixtures thereof; and water soluble or water dispersible bases such as sodium hydroxide, ammonium hydroxide, ammonia, or amines such as triethylamine, methylethyl amine, or mixtures thereof.
- mineral acids such as hydrofluoric acid, fluoroboric acid, phosphoric acid, and the like, including mixtures thereof
- organic acids such as lactic acid, acetic acid, citric acid, sulfamic acid, or mixtures thereof
- water soluble or water dispersible bases such as sodium hydroxide, ammonium hydroxide, ammonia, or amines such as triethylamine, methylethyl amine, or mixtures thereof.
- the pretreatment coating composition can be applied by any of these conventional processes.
- the substrate is cleaned and rinsed and then usually contacted with the pretreatment coating composition by roll coating with a chemical coater.
- the treated strip is then dried by heating and painted and baked by conventional coil coating processes.
- Mill application of the pretreatment composition can be by immersion, spray or roll coating applied to the freshly manufactured metal strip.
- Excess pretreatment composition is typically removed by wringer rolls.
- the metal can be rinsed with deionized water and dried at room temperature or at elevated temperatures to remove excess moisture from the treated substrate surface and cure any curable coating components to form the pretreatment coating.
- the treated substrate can be heated at about 65°C to about 125°C for about 2 to about 30 seconds to produce a coated substrate having a dried residue of the pretreatment coating composition thereon. If the substrate is already heated from the hot melt production process, no post application heating of the treated substrate is required to facilitate drying. The temperature and time for drying the coating will depend upon such variables as the percentage of solids in the coating, components of the coating composition and type of substrate.
- the film coverage of the residue of the pretreatment composition generally ranges from about 1 to about 1000 milligrams per square meter (mg/m 2 ) , and is preferably about 10 to about 400 mg/m 2 .
- a weldable coating composition is deposited upon at least a portion of the pretreatment coating.
- the weldable coating composition comprises one or more electroconductive pigments dispersed throughout a binder which provide electroconductivity and cathodic protection to the weldable coating and one or more binders which adhere the electroconductive pigment to the pretreatment coating.
- Non-limiting examples of suitable electroconductive pigments include zinc (preferred) , aluminum, iron, graphite, diiron phosphide and mixtures thereof.
- Preferred zinc particles are commercially available from ZINCOLI GmbH as ZINCOLI S 620 or 520.
- the average particle size (equivalent spherical diameter) of the electroconductive pigment particles generally is less than about 10 micrometers, preferably ranges from about 1 to about 5 micrometers, and more preferably about 3 micrometers.
- the weldable coating composition must comprise a substantial amount of electroconductive pigment, generally greater than about 10 volume percent and preferably about 30 to about 60 volume percent on a basis of total volume of electroconductive pigment and binder.
- the binder is present to secure the electroconductive pigment to the pretreatment coating.
- the binder forms a generally continuous film when applied to the surface of the pretreatment coating.
- the amount of binder can range from about 5 to about 50 weight percent of the weldable coating composition on a total solids basis, preferably about 10 to about 30 weight percent and more preferably about 10 to about 20 weight percent.
- the binder can comprise oligomeric binders, polymeric binders and mixtures thereof.
- the binder is preferably a resinous polymeric binder material selected from thermosetting binders, thermoplastic binders or mixtures thereof.
- thermosetting materials include polyesters, epoxy-containing materials, phenoxy-containing materials, polyurethanes, and mixtures thereof, in combination with crosslinkers such as aminoplasts or isocyanates which are discussed below.
- suitable thermoplastic binders include high molecular weight epoxy resins, defunctionalized epoxy resins, vinyl polymers, polyesters, polyolefins, polyamides, polyurethanes, acrylic polymers and mixtures thereof.
- useful binder materials include phenoxy polyether polyols and inorganic silicates.
- binder materials are polyglycidyl ethers of polyhydric phenols having a weight average molecular weight of at least about 2000 and preferably ranging from about 5000 to about 100,000. These materials can be epoxy functional or defunctionalized by reacting the epoxy groups with phenolic materials. Such binders can have epoxy equivalent weights of about 2000 to about one million.
- useful epoxy resins are commercially available from Shell Chemical Company as EPON® epoxy resins.
- EPON® epoxy resins include EPON® 1009, which has an epoxy equivalent weight of about 2300-3800.
- Useful epoxy defunctionalized resins include phenoxy resins such as EPONOL resin 55-BK-30 which is commercially available from Shell.
- Suitable crosslinkers or curing agents are described in U. S. Patent No. 4,346,143 at column 5, lines 45-62 and include blocked or unblocked di- or polyisocyanates such as DESMODUR® BL 1265 toluene diisocyanate blocked with caprolactam, which is commercially available from Bayer, and aminoplasts such as etherified derivatives of urea-melamine- and benzoguanamine-formaldehyde condensates which are commercially available from CYTEC Industries under the trademark CYMEL® and from Solutia under the trademark RESIMENE®.
- blocked or unblocked di- or polyisocyanates such as DESMODUR® BL 1265 toluene diisocyanate blocked with caprolactam, which is commercially available from Bayer
- aminoplasts such as etherified derivatives of urea-melamine- and benzoguanamine-formaldehyde condensates which are commercially available from CYTEC Industries under the trademark CYM
- the weldable coating composition comprises one or more diluents for adjusting the viscosity of the composition so that it can be applied to the metal substrate by conventional coating techniques.
- the diluent should be selected so as not to detrimentally affect the adhesion of the weldable coating to the pretreatment coating upon the metal substrate.
- Suitable diluents include ketones such as cyclohexanone (preferred) , acetone, methyl ethyl ketone, methyl isobutyl ketone and isophorone; esters and ethers such as 2-ethoxyethyl acetate, propylene glycol monomethyl ethers such as DOWANOL PM, dipropylene glycol monomethyl ethers such as DOWANOL DPM or propylene glycol methyl ether acetates such as PM ACETATE which is commercially available from Dow Chemical; and aromatic solvents such as toluene, xylene, aromatic solvent blends derived from petroleum such as SOLVESSO®.
- the amount of diluent can vary depending upon the method of coating, the binder components and the pigment-to- binder ratio, but generally ranges from about 10 to about 50 weight percent on a basis of total weight of the weldable coating composition.
- the weldable coating composition can further comprise optional ingredients such as phosphorus-containing materials, including metal phosphates or the organophosphates discussed in detail above; inorganic lubricants such as GLEITMO 1000S molybdenum disulfide particles which are commercially available from Fuchs of Germany; extender pigments such as iron oxides and iron phosphides; flow control agents; thixotropic agents such as silica, montmorillonite clay and hydrogenated castor oil; anti-settling agents such as aluminum stearate and polyethylene powder; dehydrating agents which inhibit gas formation such as silica, lime or sodium aluminum silicate; and wetting agents including salts of sulfated castor oil derivatives such as DEHYSOL R.
- inorganic lubricants such as GLEITMO 1000S molybdenum disulfide particles which are commercially available from Fuchs of Germany
- extender pigments such as iron oxides and iron phosphides
- flow control agents such as silica, montmor
- pigments such as carbon black, iron oxide, magnesium silicate (talc) , zinc oxide and corrosion inhibiting pigments including zinc phosphate and molybdates such as calcium molybdate, zinc molybdate, barium molybdate and strontium molybdate and mixtures thereof can be included in the weldable coating composition.
- these optional ingredients comprise less than about 20 weight percent of the weldable coating composition on a total solids basis, and usually about 5 to about 15 weight percent.
- the weldable coating composition is essentially free of chromium- containing materials, i.e., comprises less than about 2 weight percent of chromium-containing materials and more preferably is free of chromium-containing materials.
- the preferred weldable coating composition includes EPON® 1009 epoxy-functional resin, zinc dust, salt of a sulfated castor oil derivative, silica, molybdenum disulfide, red iron oxide, toluene diisocyanate blocked with caprolactam, melamine resin, dipropylene glycol methyl ether, propylene glycol methyl ether acetate and cyclohexanone .
- the weldable coating composition can be applied to the surface of the pretreatment coating by any conventional method well known to those skilled in the art, such as dip coating, direct roll coating, reverse roll coating, curtain coating, air and airless spraying, electrostatic spraying, pressure spraying, brushing such as rotary brush coating or a combination of any of the techniques discussed above.
- the thickness of the weldable coating can vary depending upon the use to which the coated metal substrate will be subjected. Generally, to achieve sufficient corrosion resistance for coil metal for automotive use, the applied weldable coating should have a film thickness of at least about 1 micrometer (about 0.5 mils), preferably about 1 to about 20 micrometers and more preferably about 2 to about 5 micrometers. For other substrates and other applications, thinner or thicker coatings can be used.
- the weldable coating is preferably dried and/or any curable components thereof are cured to form a dried residue of the weldable coating upon the substrate.
- the dried residue can be formed at an elevated temperature ranging up to about 300°C peak metal temperature.
- Many of the binders such as those prepared from epoxy-containing materials require curing at an elevated temperature for a period of time sufficient to vaporize any diluents in the coating and to cure or set the binder. In general, baking temperatures will be dependent upon film thickness and the components of the binder. For preferred binders prepared from epoxy-containing materials, peak metal temperatures of about 150°C to about 300°C are preferred.
- the metal substrate can be stored or forwarded to other operations, such as forming, shaping, cutting and/or welding operations to form the substrate into parts such as fenders or doors and/or to a subsequent electrocoat or top coating operations. While the metal is being stored, transported or subjected to subsequent operations, the coatings protect the metal surface from corrosion, such as white and red rust, due to exposure to atmospheric conditions.
- top coat of the coated substrate by electrodeposition is of particular interest.
- Compositions and methods for electrodepositing coatings are well known to those skilled in the art and a detailed discussion thereof is not believed to be necessary. Useful compositions and methods are discussed in U. S. Patent No. 5,530,043 (relating to anionic electrodeposition) and U. S. Patent Nos. 5,760,107, 5,820,987 and 4,933,056 (relating to cationic electrodeposition) .
- the weldable coated metal substrate optionally can be coated with a metal phosphate coating, such as zinc phosphate, which is deposited upon at least a portion of the weldable coating.
- a metal phosphate coating such as zinc phosphate
- Methods of application and compositions for such metal phosphate coatings are disclosed in U. S. Patent Nos. 4,941,930 and 5,238,506.
- the present invention will now be illustrated by the following specific, non-limiting examples. All parts and percentages are by weight unless otherwise indicated.
- Electrogalvanized and hot-dipped galvannealled steel substrates used for coating and testing were provided by USX. Each panel was about 10.16 centimeters (cm) (4 inches) wide, about 30.48 cm (12 inches) long and about 0.76 to 0.79 mm (0.030 to 0.031 inches) thick.
- the steel panels were subjected to an alkaline cleaning process by spraying with a 2% by volume bath of CHEMKLEEN 163 which is available from PPG Industries, Inc. at a temperature of 60°C (140°F) for 60 seconds.
- the panels were removed from the alkaline cleaning bath, rinsed with room temperature water (about 21°C (70°F) ) for 15 seconds and dried with warm air blowers.
- the panels were treated with one of the following pretreatment coatings: a solution of fluorozirconic acid containing 100 ppm Zr at pH 3.75 (Example 1) or a of fluorozirconic acid containing 1000 ppm Zr at pH 3.79 (Example 2). All pretreatment solutions were applied via roll coat application at 3.4 x 10 5 Pa (50 psi) and a rate of 56.4 meters/min (185 ft/min) . Panels were immediately baked for 15 seconds to a peak metal temperature of 110°C + 6°C (230°F+ 10°F) .
- Corrosion performance was determined by putting the above-coated panels in the General Motors 9511P cyclic corrosion test. Relative ratings according to the percentage of red rust which formed over the entire tested surface of the panel, are shown in Table 1.
- the pretreatment coating and weldable coating provide the metal substrate of the present invention with improved adhesion and flexibility and resistance to humidity, salt spray corrosion and components of subsequently applied coatings.
- the disposal and use problems associated with chromium can be reduced or eliminated.
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- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- General Chemical & Material Sciences (AREA)
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Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
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US13361799P | 1999-05-11 | 1999-05-11 | |
US133617P | 1999-05-11 | ||
US56736800A | 2000-05-09 | 2000-05-09 | |
US567368 | 2000-05-09 | ||
PCT/US2000/012675 WO2000068325A2 (en) | 1999-05-11 | 2000-05-10 | Weldable, coated metal substrates and methods for preparing and inhibiting corrosion of the same |
Publications (1)
Publication Number | Publication Date |
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EP1181107A2 true EP1181107A2 (de) | 2002-02-27 |
Family
ID=26831527
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP00932216A Withdrawn EP1181107A2 (de) | 1999-05-11 | 2000-05-10 | Korrosionsbeständige verschweissbare metall-substrate und verfahren zu ihrer herstellung |
Country Status (6)
Country | Link |
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EP (1) | EP1181107A2 (de) |
JP (1) | JP2002543998A (de) |
KR (1) | KR20010113920A (de) |
BR (1) | BR0011519A (de) |
CA (1) | CA2372745A1 (de) |
WO (1) | WO2000068325A2 (de) |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
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JP4652592B2 (ja) * | 2001-03-15 | 2011-03-16 | 日本ペイント株式会社 | 金属表面処理剤 |
US6777033B2 (en) | 2002-03-18 | 2004-08-17 | E. I. Du Pont De Nemours And Company | Process for refinishing substrates |
US7147897B2 (en) | 2002-11-06 | 2006-12-12 | Ppg Industries Ohio, Inc. | Weldable compositions comprising a conductive pigment and silicon and methods for using the same |
US7345101B2 (en) | 2002-11-06 | 2008-03-18 | Ppg Industries Ohio, Inc. | Aqueous composition of reaction product of epoxy and phosphorus materials with curing agent |
US20040086718A1 (en) | 2002-11-06 | 2004-05-06 | Pawlik Michael J | Corrosion and alkali-resistant compositions and methods for using the same |
FR2867199B1 (fr) * | 2004-03-03 | 2006-06-23 | Ppg Ind France | Procede pour l'obtention d'un substrat mettalique comportant un revetement protecteur |
JP2007262488A (ja) * | 2006-03-28 | 2007-10-11 | Nippon Steel Corp | 金属(水)酸化物被覆めっき線材 |
WO2009073716A1 (en) * | 2007-12-04 | 2009-06-11 | Sulzer Metco (Us) Inc. | Multi-layer anti-corrosive coating |
KR101086847B1 (ko) * | 2011-01-20 | 2011-11-24 | 이계영 | 접동부재용 코팅 조성물 |
AU2013309269B2 (en) | 2012-08-29 | 2016-03-31 | Ppg Industries Ohio, Inc. | Zirconium pretreatment compositions containing lithium, associated methods for treating metal substrates, and related coated metal substrates |
EP3293287A1 (de) | 2012-08-29 | 2018-03-14 | PPG Industries Ohio, Inc. | Zirkoniumvorbehandlungszusammensetzung mit molybdän, zugehörige verfahren zur behandlung von metallsubstraten und zugehörige beschichtete metallsubstrate |
CA2982739C (en) | 2015-04-15 | 2023-06-27 | Henkel Ag & Co. Kgaa | Thin corrosion protective coatings incorporating polyamidoamine polymers |
KR20190043155A (ko) | 2016-08-24 | 2019-04-25 | 피피지 인더스트리즈 오하이오 인코포레이티드 | 금속 기판을 처리하기 위한 알칼리성 조성물 |
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US5001173A (en) * | 1987-05-11 | 1991-03-19 | Morton Coatings, Inc. | Aqueous epoxy resin compositions and metal substrates coated therewith |
US5653823A (en) * | 1995-10-20 | 1997-08-05 | Ppg Industries, Inc. | Non-chrome post-rinse composition for phosphated metal substrates |
US6440580B1 (en) * | 1998-12-01 | 2002-08-27 | Ppg Industries Ohio, Inc. | Weldable, coated metal substrates and methods for preparing and inhibiting corrosion of the same |
-
2000
- 2000-05-10 JP JP2000616294A patent/JP2002543998A/ja active Pending
- 2000-05-10 BR BR0011519-3A patent/BR0011519A/pt not_active IP Right Cessation
- 2000-05-10 CA CA002372745A patent/CA2372745A1/en not_active Abandoned
- 2000-05-10 KR KR1020017014324A patent/KR20010113920A/ko not_active Application Discontinuation
- 2000-05-10 EP EP00932216A patent/EP1181107A2/de not_active Withdrawn
- 2000-05-10 WO PCT/US2000/012675 patent/WO2000068325A2/en not_active Application Discontinuation
Non-Patent Citations (1)
Title |
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See references of WO0068325A2 * |
Also Published As
Publication number | Publication date |
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WO2000068325A3 (en) | 2001-05-25 |
BR0011519A (pt) | 2002-03-26 |
JP2002543998A (ja) | 2002-12-24 |
KR20010113920A (ko) | 2001-12-28 |
CA2372745A1 (en) | 2000-11-16 |
WO2000068325A2 (en) | 2000-11-16 |
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