US2535794A - Method of preparing ferrous metal objects for the application of synthetic resins - Google Patents

Method of preparing ferrous metal objects for the application of synthetic resins Download PDF

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Publication number
US2535794A
US2535794A US724248A US72424847A US2535794A US 2535794 A US2535794 A US 2535794A US 724248 A US724248 A US 724248A US 72424847 A US72424847 A US 72424847A US 2535794 A US2535794 A US 2535794A
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United States
Prior art keywords
dichromate
ferrous metal
acid
solution
application
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US724248A
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Hempel Charles Henry
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Heresite and Chemical Co
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Heresite and Chemical Co
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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
    • B05D7/16—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 using synthetic lacquers or varnishes
    • 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
    • C23C22/24—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 hexavalent chromium compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31942—Of aldehyde or ketone condensation product

Definitions

  • This invention relates to a method of treating steel surfaces to prepare them for the application of oil-free synthetic resins, and more particularly for the application of oil-free phenol-formaldehyde resins.
  • a common method of preparation is to apply a sand blast or its equivalent; the sand blasting process, however, involves the human element to such an extent that it is not always uniform and the present method gives a process which may be mechanically controlled and produces better and more uniform results than the sand blast treatment.
  • the steel or other ferrous metal surfaces are cleaned of any adhering grease by a suitable grease solvent.
  • a suitable grease solvent This is preferably a 3 to 5% solution of caustic alkali at a temperature of 15 to 80 C. Ordinarily two to fifteen minutes treatment is required, depending upon the surface condition ofv the steel.
  • the metal is washed free of alkali and is then etched with a suitable acid to produce a clean crystalline appearance. This may be accomplished by first dipping the metal in a solution of hydrochloric acid of 15 to 38% concentration at a temperature of 25 to 90 C. for 3 to 30 minutes. A minute period is usually satisfactory in 30% hydrochloric acid at 75 C.
  • the metal is then rinsed in water and dipped momentarily in a 1% solution of alkali metal dlchromate.
  • This dichromate solution should contain a small proportion of added alkali material, suitably sodium carbonate in amounts from 1 to 2% of the dichromate may be used.
  • the percentage of dichromate may be reduced slightly, or it may be increased somewhat, but increasing the amount of the material does not add to the effectiveness of the process.
  • the effect of the acid dip is to create a thin film of a ferric salt on the surface of the metal.
  • the ferric ions on the surface of the metal react with the dichromate ions forming ferric chromate, which is insoluble under the conditions and adheres to the metal in the form of a thin, invisible, probably monomolecular coating.
  • the metal may be dipped into" to 70% nitric acid at room temperature (17 C.) for onehalf to four minutes, followed by a dip, after cleaning, in 15 to 75% sulphuric acid.
  • the sulphuric acid is maintained at 25 to 90 C. and immersion may be from 1 to 15 minutes.
  • the metal is treated as before in a dichromate solution.
  • Steel or other similar ferrous meal materials when treated in this manner may be Water rinsed and dried at relatively high temperatures without any oxidation which will interfere with the adherence of a synthetic varnish or enamel. The surface will not rust for periods of twentyfour hours or even somewhat longer.
  • the steel surface when so prepared has remarkable adherence to synthetic varnishes and enamels, such as phenolic, either urea or formaldehyde, alkyd, vinyl and chlorinated rubber type.
  • synthetic varnishes and enamels such as phenolic, either urea or formaldehyde, alkyd, vinyl and chlorinated rubber type.
  • the surface is especially adherent to oilfree phenol formaldehyde resins of the type disclosed in Hempel Patent No. 2,198,939. Those resins are applied by spraying or dipping while in the liquid A stage, and then are baked to the infusible, hard C stage.
  • a steel sheet was immersed in a 5% solution of caustic maintained at a temperature of C. and held therein for five minutes. It was then washed in Water and dipped for twelve minutes in a solution of 25% sulphuric acid maintained at 75 C. It was then rinsed and dipped in a 1% solution of sodium dichromate containing sodium. carbonate in an amount approximately 2% of the dichromate. It was immediately removed from this bath, rinsed in water while still wet from the dichromate soltuion and dried. It was then coated with an oil-free phenol formaldehyde resin of the type disclosed in Hempel Patent No. 2,198,939.
  • the method which comprises etching a ferrous metal object with an acid, removing the acid, dipping the object in a dilute solution of alkali metal dichromate, removing the object therefrom, washing the object while still wet from the dichromate solution and drying it and then baking an oil-free phenolic resin coating thereon.
  • the method which comprises etching a ferrous metal object with an acid chosen from the class consisting of hydrochloric, esulphuric and nitric acids, removing the acid, dipping the object in an approximately 1% solution of alkali metal dichromate to which has been added :80- dium carbonate in an amount of 1 to 2% 0f the dichromate, washing the object in water'while still wet from the dichromate solution and drying it, applying a protective coating of an oil-'.free ;.phenol:-formaldehyde resin in the A-stage:1to thelobiectsan'd then baking the coating thereon.
  • an acid chosen from the class consisting of hydrochloric, esulphuric and nitric acids
  • a ferrous metal object havingharbakedrphenolic resin coating thereon prepared by'themethod of claim 1.
  • a ferrous metal object having a bakedphw nolic resin coating thereon prepared by the meth- 20 red ofclaim 2.
  • a ferrous metal object having a baked, oil-o free phenol-formaldehyde resin coating thereon prepared by the method of claim 4.

Description

Patented Dec. 26, 1950 METHOD OF PREPARING FERROUS METAL OBJECTS FOR THE'APPLICATIQN OF SYN THETIC RESIN S Charles Henry Hempel, Manitowoc, Wis., assignor to Heresite & Chemical Company, a corporation of Wisconsin ,No Drawing. Application January 24, 1947,
Serial No. 724,248
8 Claims. (01. 148-6.2)
This invention relates to a method of treating steel surfaces to prepare them for the application of oil-free synthetic resins, and more particularly for the application of oil-free phenol-formaldehyde resins.
It has been recognized that phenol-formaldehyde type coatings, when oil-free, cannot be applied to unprepared steel surfaces.
A common method of preparation is to apply a sand blast or its equivalent; the sand blasting process, however, involves the human element to such an extent that it is not always uniform and the present method gives a process which may be mechanically controlled and produces better and more uniform results than the sand blast treatment.
In carrying out the present process, the steel or other ferrous metal surfaces are cleaned of any adhering grease by a suitable grease solvent. This is preferably a 3 to 5% solution of caustic alkali at a temperature of 15 to 80 C. Ordinarily two to fifteen minutes treatment is required, depending upon the surface condition ofv the steel. After cleaning the metal is washed free of alkali and is then etched with a suitable acid to produce a clean crystalline appearance. This may be accomplished by first dipping the metal in a solution of hydrochloric acid of 15 to 38% concentration at a temperature of 25 to 90 C. for 3 to 30 minutes. A minute period is usually satisfactory in 30% hydrochloric acid at 75 C.
The metal is then rinsed in water and dipped momentarily in a 1% solution of alkali metal dlchromate. This dichromate solution should contain a small proportion of added alkali material, suitably sodium carbonate in amounts from 1 to 2% of the dichromate may be used.
The percentage of dichromate may be reduced slightly, or it may be increased somewhat, but increasing the amount of the material does not add to the effectiveness of the process.
The effect of the acid dip is to create a thin film of a ferric salt on the surface of the metal. Upon dipping the metal into the dichromate solution, the ferric ions on the surface of the metal react with the dichromate ions forming ferric chromate, which is insoluble under the conditions and adheres to the metal in the form of a thin, invisible, probably monomolecular coating.
Instead of the use of the hydrochloric acid bath the metal may be dipped into" to 70% nitric acid at room temperature (17 C.) for onehalf to four minutes, followed by a dip, after cleaning, in 15 to 75% sulphuric acid. The sulphuric acid is maintained at 25 to 90 C. and immersion may be from 1 to 15 minutes. After removal from the sulphuric acid the metal is treated as before in a dichromate solution.
Steel or other similar ferrous meal materials when treated in this manner may be Water rinsed and dried at relatively high temperatures without any oxidation which will interfere with the adherence of a synthetic varnish or enamel. The surface will not rust for periods of twentyfour hours or even somewhat longer.
The steel surface when so prepared has remarkable adherence to synthetic varnishes and enamels, such as phenolic, either urea or formaldehyde, alkyd, vinyl and chlorinated rubber type. The surface is especially adherent to oilfree phenol formaldehyde resins of the type disclosed in Hempel Patent No. 2,198,939. Those resins are applied by spraying or dipping while in the liquid A stage, and then are baked to the infusible, hard C stage.
As a specific example of the invention, a steel sheet was immersed in a 5% solution of caustic maintained at a temperature of C. and held therein for five minutes. It was then washed in Water and dipped for twelve minutes in a solution of 25% sulphuric acid maintained at 75 C. It was then rinsed and dipped in a 1% solution of sodium dichromate containing sodium. carbonate in an amount approximately 2% of the dichromate. It was immediately removed from this bath, rinsed in water while still wet from the dichromate soltuion and dried. It was then coated with an oil-free phenol formaldehyde resin of the type disclosed in Hempel Patent No. 2,198,939.
Iclaim:
1. The method which comprises etching a ferrous metal object with an acid, removing the acid, dipping the object in a dilute solution of alkali metal dichromate, removing the object therefrom, washing the object while still wet from the dichromate solution and drying it and then baking an oil-free phenolic resin coating thereon.
2. The method set forth in claim 1, in which the synthetic resin is a phenol formaldehyde resin.
3. The method for preparing a ferrous metal object for the application of a phenolic resin coating which comprises etching the object with an acid, removing the acid, dipping the object in an approximately 1% solution of alkali metal dichromate to which has been added sodium carbonate in an amount of 1 to 2% of the dichromate, re-
-' moving the object therefrom, washing the oblect in water while still wet from the dichromate solution and then drying the object.
4. The method which comprises etching a ferrous metal object with an acid chosen from the class consisting of hydrochloric, esulphuric and nitric acids, removing the acid, dipping the object in an approximately 1% solution of alkali metal dichromate to which has been added :80- dium carbonate in an amount of 1 to 2% 0f the dichromate, washing the object in water'while still wet from the dichromate solution and drying it, applying a protective coating of an oil-'.free ;.phenol:-formaldehyde resin in the A-stage:1to thelobiectsan'd then baking the coating thereon.
5. A ferrous metal object havingharbakedrphenolic resin coating thereon prepared by'themethod of claim 1.
6. A ferrous metal object having a bakedphw nolic resin coating thereon prepared by the meth- 20 red ofclaim 2.
1:7. Aferrouslmetalobjectpreparedzbyethemethocl'o'f claimfi.
removing the object therefrom,
8. A ferrous metal object having a baked, oil-o free phenol-formaldehyde resin coating thereon prepared by the method of claim 4.
CHARLES HENRY HEMPEL,
TREFERE1\1'.CES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 12,114,151 ..Romi g Apr. 12, 1938 2498,9359 .LHempel Apr. 30, 1940 2288;182 :Curtin June 30, 1942 2,314,565 .Thompson Mar. 23, 1943 1 21315564 "Thompson et a1 Apr. 6, 1943 "2, i20,134 Hem'pel et a1. May 6, 1947 FOREIGN PATENTS ,Number Country :Date
" 799,695 ,France :Apr. 1aI-rl 1936

Claims (1)

1. THE METHOD WHICH COMPRISES ETCHING A FERROUS METAL OBJECT WITH AN ACID, REMOVING THE ACID, DIPPING HTE OBJECT IN A DILUTE SOLUTION OF ALKALI METAL DICHROMATE, REMOVING THE OBJECT THEREFROM, WASHING THE OBJECT WHILE STILL WET FROM THE DICHROMATE SOLUTION AND DRYIN GIT AND THEN BAKING AN OIL-FREE PHENOLIC RESIN COATING THEREON.
US724248A 1947-01-24 1947-01-24 Method of preparing ferrous metal objects for the application of synthetic resins Expired - Lifetime US2535794A (en)

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2620265A (en) * 1950-09-28 1952-12-02 Kaiser Aluminium Chem Corp Composition for treating aluminum and aluminum alloys
US2718485A (en) * 1953-07-21 1955-09-20 Paul P Heinley Method of bonding mechanical elements
US2768103A (en) * 1952-03-18 1956-10-23 Heintz Mfg Co Method for coating metals
US2768104A (en) * 1952-03-25 1956-10-23 Heintz Mfg Co Method for coating iron
US2773623A (en) * 1954-06-01 1956-12-11 Heintz Mfg Co Corrosion resistant coated steel members and method of making
US2777785A (en) * 1953-07-30 1957-01-15 Heintz Mfg Co Composition for and method of treating metals as well as the treated product
US2811471A (en) * 1954-05-10 1957-10-29 Connecticut Hard Rubber Co Polytrifluorochloroethylene-coated aluminum
US2837443A (en) * 1954-07-26 1958-06-03 Eagle Picher Co Method of porcelain enameling
US2853406A (en) * 1956-04-17 1958-09-23 Kelsey Hayes Co Metal coating
US2887367A (en) * 1956-11-13 1959-05-19 Ford Motor Co Resist etching
US2895389A (en) * 1954-09-16 1959-07-21 Reliance Steel Prod Co Coatings for the traffic bearing surfaces of grating
US3036934A (en) * 1958-03-17 1962-05-29 Bethlehem Steel Corp Coated article and method of making same
US3351421A (en) * 1965-05-14 1967-11-07 Lockheed Aircraft Corp Method for treatment of corrosion
US5956816A (en) * 1998-03-18 1999-09-28 Mccrink; David J. Elastomer coating for buttons, and method therefor

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR799695A (en) * 1935-03-21 1936-06-17 Pneumatiques Dunlop Method of temporary protection against rust of stripped surfaces of ferrous metals
US2114151A (en) * 1935-07-09 1938-04-12 American Chem Paint Co Art of finishing ferrous metal
US2198939A (en) * 1939-09-25 1940-04-30 Heresite & Chemical Company Pigmented material
US2288182A (en) * 1939-04-06 1942-06-30 Curtin Howe Corp Container manufacture
US2314565A (en) * 1940-05-29 1943-03-23 Parker Rust Proof Co Coated ferrous article and method of making the same
US2315564A (en) * 1941-03-27 1943-04-06 Parker Rust Proof Co Art of coating and fabricating steel articles
US2420134A (en) * 1943-10-18 1947-05-06 Heresite & Chemical Company Coating composition comprising phenol-formaldehyde resin in a mixture of solvents

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR799695A (en) * 1935-03-21 1936-06-17 Pneumatiques Dunlop Method of temporary protection against rust of stripped surfaces of ferrous metals
US2114151A (en) * 1935-07-09 1938-04-12 American Chem Paint Co Art of finishing ferrous metal
US2288182A (en) * 1939-04-06 1942-06-30 Curtin Howe Corp Container manufacture
US2198939A (en) * 1939-09-25 1940-04-30 Heresite & Chemical Company Pigmented material
US2314565A (en) * 1940-05-29 1943-03-23 Parker Rust Proof Co Coated ferrous article and method of making the same
US2315564A (en) * 1941-03-27 1943-04-06 Parker Rust Proof Co Art of coating and fabricating steel articles
US2420134A (en) * 1943-10-18 1947-05-06 Heresite & Chemical Company Coating composition comprising phenol-formaldehyde resin in a mixture of solvents

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2620265A (en) * 1950-09-28 1952-12-02 Kaiser Aluminium Chem Corp Composition for treating aluminum and aluminum alloys
US2768103A (en) * 1952-03-18 1956-10-23 Heintz Mfg Co Method for coating metals
US2768104A (en) * 1952-03-25 1956-10-23 Heintz Mfg Co Method for coating iron
US2718485A (en) * 1953-07-21 1955-09-20 Paul P Heinley Method of bonding mechanical elements
US2777785A (en) * 1953-07-30 1957-01-15 Heintz Mfg Co Composition for and method of treating metals as well as the treated product
US2811471A (en) * 1954-05-10 1957-10-29 Connecticut Hard Rubber Co Polytrifluorochloroethylene-coated aluminum
US2773623A (en) * 1954-06-01 1956-12-11 Heintz Mfg Co Corrosion resistant coated steel members and method of making
US2837443A (en) * 1954-07-26 1958-06-03 Eagle Picher Co Method of porcelain enameling
US2895389A (en) * 1954-09-16 1959-07-21 Reliance Steel Prod Co Coatings for the traffic bearing surfaces of grating
US2853406A (en) * 1956-04-17 1958-09-23 Kelsey Hayes Co Metal coating
US2887367A (en) * 1956-11-13 1959-05-19 Ford Motor Co Resist etching
US3036934A (en) * 1958-03-17 1962-05-29 Bethlehem Steel Corp Coated article and method of making same
US3351421A (en) * 1965-05-14 1967-11-07 Lockheed Aircraft Corp Method for treatment of corrosion
US5956816A (en) * 1998-03-18 1999-09-28 Mccrink; David J. Elastomer coating for buttons, and method therefor

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