US3053702A - Metal coating - Google Patents

Metal coating Download PDF

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Publication number
US3053702A
US3053702A US814200A US81420059A US3053702A US 3053702 A US3053702 A US 3053702A US 814200 A US814200 A US 814200A US 81420059 A US81420059 A US 81420059A US 3053702 A US3053702 A US 3053702A
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United States
Prior art keywords
dichromate
coating
resin
dispersion
zinc
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US814200A
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English (en)
Inventor
Ludwig K Schuster
Jr Alfonso L Baldi
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GENNSALT CHEMICALS Corp
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GENNSALT CHEMICALS CORP
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Filing date
Publication date
Priority to NL260637D priority Critical patent/NL260637A/xx
Priority to NL286331D priority patent/NL286331A/xx
Application filed by GENNSALT CHEMICALS CORP filed Critical GENNSALT CHEMICALS CORP
Priority to US814200A priority patent/US3053702A/en
Priority claimed from US6021A external-priority patent/US3128546A/en
Priority to GB15995/60A priority patent/GB947315A/en
Priority to DEH39465A priority patent/DE1235107B/de
Priority to SE935/61A priority patent/SE308234B/xx
Priority to FR851259A priority patent/FR1287431A/fr
Publication of US3053702A publication Critical patent/US3053702A/en
Application granted granted Critical
Priority claimed from US222864A external-priority patent/US3318716A/en
Priority to GB45962/62A priority patent/GB1033399A/en
Priority to FR917798A priority patent/FR83513E/fr
Priority to DE19621444477 priority patent/DE1444477A1/de
Priority to DE19621646892 priority patent/DE1646892A1/de
Priority to BR146039/69*[A priority patent/BR6346039D0/pt
Priority to JP42061059A priority patent/JPS501130B1/ja
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
    • E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
    • E04C2/10—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products
    • E04C2/16—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products of fibres, chips, vegetable stems, or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D19/00—Degasification of liquids
    • B01D19/02—Foam dispersion or prevention
    • B01D19/04—Foam dispersion or prevention by addition of chemical substances
    • B01D19/0404—Foam dispersion or prevention by addition of chemical substances characterised by the nature of the chemical substance
    • 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
    • C09D5/08—Anti-corrosive paints
    • C09D5/10—Anti-corrosive paints containing metal dust
    • C09D5/103—Anti-corrosive paints containing metal dust containing Al
    • 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
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/41—Organic pigments; Organic dyes
    • 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
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • 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
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/65—Additives macromolecular
    • 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
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/70—Additives characterised by shape, e.g. fibres, flakes or microspheres
    • 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
    • C23C22/73—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 characterised by the process
    • C23C22/74—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 characterised by the process for obtaining burned-in conversion coatings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/10—Metal compounds
    • C08K3/11—Compounds containing metals of Groups 4 to 10 or of Groups 14 to 16 of the Periodic Table
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers

Definitions

  • the present invention relates to the coating of metal, particularly for reducing the corrosion of the metal and for giving it a colored appearance, and represents an improvement in the subject matter of U.S. Patents 2,768,103, 2,768,104, both granted October 23, 1956, and 2,773,623 granted December l1, 1956.
  • This application is in part a continuation of applications Serial No. 587,3 88, led May 25, 1956 (nou U.S. Patent 2,911,332, granted November 3, 1959), Serial No. 666,852, tiled June 20, 1957, Serial No. 708,772, filed January 14, 1958 (now abandoned but replaced by Serial No. 88,018, tiled February 9, 1961), and Serial No. 738,648, tiled May 29, 1958.
  • FIG. 1 is a partially broken away view of a can coated in accordance with the present invention.
  • FIG. 2 illustrates a baling strap coated in accordance with the present invention, the strap being shown in place around a bale, part of the coating being removed so as to better show it.
  • pigments can be incorporated in the above type of coatings to make them present very attractive appearance, but special provision is required to make the pigments compatible. Also unless the non-pigment ingredients are adjusted in proportion so as to avoid the prior brown colorations, the effect of all but the darkest pigments is largely lost. In other words, the prior brown colorations, although suiiiciently transparent to be beset by interference fringes, are still capable of seriously masking the effect of pigments, even those that impart brown colors.
  • the chromic acid is replaced by the water soluble dichromate of a metal having a valence greater than one.
  • the proportion of reducing agent is adjusted so that at least 70% of the hexavalent chromium is reduced to trivalent condition in the final coating. Accordingly, of the 40 to 95% range of reduction disclosed in the above patents, only the uppermost portion is used.
  • Suitable pigments for the purpose of the present invention are the more inert ones such as titanium dioxide, carbon, iron oxide andv the phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green. Also effective is finely divided metallic zinc which, though having relatively low tinctorial ability, greatly increases the corrosion protection which the coatings provide.
  • the pigments give their best hiding when in very nely divided form, as for example when the pigment particles are about one micron or smaller in size, but the increased protection by the zinc powder reaches a maximum when the powder particles are about 50 microns in size.
  • pigment is preferably dispersed in the coating solution in a proportion of from 10 to 75% by weight of the dichromate content. Wetting agents, particularly of the non-ionic type, are advantageously used to keep the pigment particles dispersed during the coating process.
  • the coatings should also have a minimum coating weight of at least about milligrams per square foot of surface covered. Resins are also best included in the coating, as set forth in the above-identified parent applications, inasmuch as such additions further improve the corrosion protection and also make it easier to apply very heavy coatings. Coating weights as high as 1000 to 2000 milligrams or more per square foot can be readily applied in this way. Too much resin renders the iinal coating sensitive to the action of solvents which can cause the color to become streaky as Well as dulled. To avoid this the maximum resin content should be no higher than 1 part by weight for every 3 parts of dichromate content by weight in the coating dispersion.
  • a feature of the present invention is that even without resin the presence of pigments improves the corrosion resistance contributed -by the coating. Phthalocyanine tbluc and TiO2 are particularly effective in this respect.
  • Acrylic resins such as methyl acrylate, ethyl acrylate and methyl methacrylate resins are a preferred type of resin. They can be provided in hardnesses of Tukon 2 ⁇ or more, and where the coated product is to
  • the pigment-containing coatings of the present invention are applicable to any material that can withstand the application conditions. Even paper can be so coated.
  • the invention is of primary significance in connection with the coating of metals by reason of the high corrosion resistance which the coating contributes. Indeed, the corrosion resistance is of such magnitude that the coating will even protect such metals as chromiumnickel stainless steels (18-8 for instance) which are relatively slow to corrode.
  • the coating also adheres very well to corrodible metals although in some case, as with aluminum and stainless steels, it may be helpful somewhat to roughen the surface of the metal slightly, or else not to polish the surface too much when the metal is manufactured.
  • Roughening can Ibe effected by etching or abrasion, as with sand blasting, or even -by rolling the metal between rough surface rollers.
  • roughening is not needed to improve the adhesion of the coating, but the corrosion protection of such metals can be sharply increased by giving them a preliminary grain boundary etch, as described in applicants prior application Serial No. 592,552, tiled lune 20, 1956, now Patent No. 3,031,333.
  • the coatings of the present invention can also be applied very elfectively over metals that have been given a prior adherent coating of oxide or other materials such as phosphate, oxalate, sulfide or other chromate coatings, including those used to improve the adhesion of paint to ferrous metals as well as to lubricate those metals 'for working operations. Examples of such preliminary treatments are given in the above-identified U.S. Patent 2,768,104.
  • Coatings of the present invention when so applied over the pre-coated metals give much better protection against corrosion as compared to pre-coated metals when they are not given a second coating. It is also noted that a water-base paint when applied over such double coated metals, also gives much better corrosion resistance, and for this purpose the coating of the present invention need not have any resin or pigment present and can even be applied in very thin films.
  • a milligram per square foot coating from an aqueous solution of only zinc dichromate and a compatible reducing agent like sucrose so as to cause 70 to 95% reduction of the hexavalent chromium to trivalent form when this solution is subjected to the curing step, makes a very desirable covering over plain carbon steel that has been phosphatized, as shown in Examples 13 and 14 of the above-identified Patent 2,768,104.
  • the zinc-dichromate-reducing-agent solution can be merely applied in the form of a final rinse after the phosphatizing operation, particularly when the material being treated is a formed object such as an automobile frame or chassis.
  • Metals suitable for treatment in accordance with the present invention include straight chromium steel, beryllium, cadmium chromium, cobalt, columbium, copper, lead manganese, magnesium, molybdenum, nickel, silver, tantalum, tin, titanium, vanadium, zinc, zirconium, and alloys of any of these metals with each other.
  • polytetrafluoroethylene can be used in a mixture that leaves a coating weight of 1.5 milligrams per square foot.
  • a coating mixture of 6 grams zinc dichromate 2 grams sucrose 4 cc. of an aqueous dispersion of polytetrafiuoroethylene having 50% resin solids content by weight 0.05 gram p-octyl phenyl tri-oxyethylcne ethanol diluted to 4 liters with water.
  • the resin-to-dichromate ratio can be varied over the 1.5:1 to 1:3 range mentioned earlier, and in fact the resin can be entirely omitted although this diminishes the corrosion protection somewhat.
  • the resin-free coating does not powder off but can be butfed off as described in patent application Serial No. 666,852.
  • the zinc dichromate of the above formulation can be replaced by strontium dichromate, or calcium dichromate or even For such treatment Cr03 with not much loss of effectiveness.
  • the curing can take place at any temperature between 250 and 450 F.
  • Example I An aqueous dispersion is prepared with the following formulation:
  • the above ingredients are diluted to 600 cc. with water and SAE 1010 steel strapping is dipped in it following which the strapping is rolled between grooved rollers.
  • the resulting wet metal is passed through an air oven where it momentarily reaches a temperature of 350 F.
  • the resulting article has a coating that weighs 200 milligrams per square foot and has a very pleasing black appearance. It also withstands a 98% humidity test at 95 F. for 100 hours without showing a sign of attack.
  • the coating adheres very well, cannot be scraped off with the finger nail, and does not take any impression by pressing a finger against it.
  • the above coatings also produce a very pleasing leather like appearance when applied over metal that has been roughened by rolling with rough rollers, and type 302 stainless steel panels roughened in this way and coated as per Example I, give an unusually attractive appearance.
  • curing temperatures of 250 to 450 F. can be used with pigment-free coatings, the higher conversion needed for pigment-containing coatings requires a minimum curing temperature of about 280 F.
  • Ti02 is a white pigment, it normally colors the coating a pastel green, and when combined with phthalocyanine blue it will provide a darker green color. When mixed with carbon black it gives a pleasing grey. Phthalocyanine green also supplies a green color, red iron oxide a red color, and phthalocyanine blue a striking blue color.
  • the coating solution can also be applied by spraying, and by adjusting the spray operation, the aqueous medium of the coating dispersion can be caused to evaporate in considerable proportions before the spray particles reach the surface being coated.
  • the addition of air jets surrounding the spray jet can be arranged to evaporate as much as 3A of the water in the traveling of the sprayed particles to the surface being coated.
  • the sprayed particles deposit on the surface in a more or less Viscous form which does not run to any appreciable degree and furthermore builds up quite readily to give coatings weighing as much as 5,000 milligrams per square foot.
  • This type of coating is of special significance in the treatment of fabricated articles where running of the coating is to be avoided. Regardless of the coating thickness, the curing operation can be completed in a few seconds.
  • polyvinyl stearate can be one produced by reacting polyvinyl alcohol with sufficient stearoyl chloride to cause about half of the hydroxyl content of the polyvinyl alcohol to become esteried, or can be a fully esterified material such as made in the manner described in U.S. Patents 2,188,864 and 2,562,965.
  • the plasticizer can be added in an amount up to about 25% of the weight of any plasticized resin and the metal so coated is suitable for high speed stamping operations such as in the making of tops and bottoms for cans used in conventional canning.
  • FIG. 1 shows such a can l0.
  • the can has a tubular body 12 made in the conventional manner from a single strip ⁇ of a full bright finished black plate l mils thick with the ends joined together as indicated at l. These ends are folded back on each other to provide interlocking flanges 16 and 18 between which a yielding gasket layer 1"/ such as rubber is applied. The flange and gasket combination is then crimped together to make a suitably sturdy and leak-proof joint.
  • the openings at the top and bottom of the tubular body are sealed with covers 20, 22 that have beaded peripheries 24 with interlocking flanges 26, 28.
  • Circular strengthening ribs 36 can also be formed in the top and bottom.
  • the interlocking beaded periphery can merely be crimped, preferably with a layer 30 of gasketing to assure hermetical sealing.
  • the metal of the can body as well as the top and bottom, has a coating 34 applied in accordance with the present invention.
  • This coating was provided on the unfabricated sheet by subjecting it to the following operations:
  • Example II A Clean the black plate cathodically in an aqueous solution containing 16 grams KOH per liter using a current density of ⁇ amperes per square foot of cathode at 14C-160 F. for l0 seconds.
  • thermosetting butadiene-styrene resin similar to that described in Example 1 of U.S. Patent 2,683,698 but using styrene in place of the mixed vinyl toluenes, and omitting the sodium bicarbonate;
  • the metal is in the form of an elongated strip, it may be coiled up directly after step L.
  • the resulting coating weighs approximately 200 milligrams per square foot.
  • coated sheet which -in the above example is colored pale green, can be used for making both the top and bottom 20, 22 of the can 'as well as the body 12 (FIG. 1) by stamping land crimping operation, although in some cases different thicknesses of metal can be used in the different portions of the can so that separate coated sheets are required.
  • the cover on one end may be applied in any convenient manner such as the one generally used -in the industry ⁇ and shown in FIG. 1.
  • the corrosion resistance of the thus treated metal is outstanding and is better than that of tin-plated cans.
  • the cans having the coating of the present invention are particularly useful in storing such materials as detergents, soaps and other alkaline compositions, and are also suitable for holding chemicals yand other items that are neutral or acid in reaction.
  • the stamping of the can tops involves a fairly abrupt deformation of the margin 318 to provide a backing for the bead crimping operation.
  • the presence of the pigment does not significantly detract from the effectiveness of the coating in withstanding such deformation.
  • the resin is preferably of the butadiene-styrene type or contains about l0 to 25% plasticizer.
  • Example III 'Ihe procedure of Example II is followed except that step J is carried out by rolling the metal between rough rubber rolls wet with the following dispersion:
  • the curing temperature is reduced to about 320 F.
  • a very attractive and protective deep blue finish results.
  • the coloring of the present ⁇ invention can be limited to only the top and bottom.
  • the remainder of the can may be made from metal coated in other manners such as with the pigmentfree coatings of patents numbered 2,768,103, 2,768,104 and 2,773,623 as well ⁇ as application Serial No. 738,648.
  • the omission of the pigment means that thinner coatings can be used, particularly if of the resin-free type.
  • the outer surfaces can, for example, .be of the pigmented type containing zinc either as pigment or as a sublayer (see Example IV), while the inner surfaces can have the pigment-free and zinc-free coatings.
  • masks that provide the three-color separation for individual element-s of the screen can be made by etching or otherwise forming ne apertures in ⁇ a sheet of metal such as iron or copper, and the completed mask can be coated with a dilute aqueous solution of 2% chromic acid and 273% reducing agent such as triethanolamine, after which the mask can be drained to free it from excess solution and then heated to 250 F. to cure the coating.
  • a dilute aqueous solution of 2% chromic acid and 273% reducing agent such as triethanolamine
  • An exceptionally effective coating according to the present invention uses a thin undercoat of electrodeposited zinc.
  • a typical technique of this type is:
  • Example 1V SAE 1020 steel sheet is cleaned in a 2% aqueous NaOH dip at 180 F., rinsed with cold tap water and then electrolyzed -as a cathode in the following bath:
  • the current density is adjusted to 11 amperes per square foot of cathode, the bath temperature to 45 C., and the electrolyzing continued until a 150 milligram per square foot layer of zinc is deposited.
  • the zinc-covered metal is again rinsed with tap water, and sprayed with the following aqueous formulation:
  • Percent Zinc dichromate 45 Sucrose 8.1 Thermosetting butadiene-styrene resin solids 27.2 Polyvinyl stearate 9.4 TiOZ 9.5 p-Octyl phenyl tri-ethylene oxyethanol 0.8
  • the sprayed metal is cured at 375 F. to leave a coating weighing 200 milligrams per squared foot.
  • the resulting coated product withstands corrosion better than aluminum-painted steel, even in sharply deformed areas.
  • pigmented coatings of the present invention are formed from formulations such as Example V To 6000 cc. water are added 4 grams of p-octyl phenyl tri-ethylene oxyethanol 500 grams SrCr2O7 300 grams phthalocyanine green, and
  • Example VI 1000 cc. water 100 grams MgCrzOq made by reacting 7 parts of MgCO3 with an excess (l1 parts)l of CrO3 40 grams H3PO3 grams red iron oxide 4 grams dioctyl sodium sulfosuccinate.
  • Flaming can also be very efficiently used to cure the resincontaining coatings of the present invention, and in fact is suitable for drying or curing any kind of organic coat such as water-based paints, water-dispersed resin, and even paints having organic thinners. Where the thinners are combustible most of the thinner should be evaporated off before the paint layer reaches the flaming zone.
  • the coating dispersions of the present invention can tolerate a small amount of excess CrO3 as indicated by the formulation of Example VI. Resin can also be present along with the excess CrO3 as for instance by adding to the formulation of Example VI 50 grams of the alkyd resin of Example I in U.S. Patent 2,634,245 emulsied with A the amount of polyethylene glycols there described.
  • FIG. 2 shows an application of the present invention where the coloring is more significant than the corrosion resistance.
  • a bale 40 of cotton for example, is here shown as held by baling straps 41, 42 coated in accordance with the present invention.
  • These straps can be of standard types of steels such as ordinary SAE 1010 or SAE 1020 steel, preferably given an extra severe rolling operation to increase the springiness and hardness of the steel somewhat.
  • SAE 1010 or SAE 1020 steel preferably given an extra severe rolling operation to increase the springiness and hardness of the steel somewhat.
  • the grain boundary etch sharply increases the corrosion resistance and is valuable where straps are exposed to severe corrosion conditions.
  • the grain boundary etch as with nitric acid in the manner shown in Example II or in U.S. Patent application Serial No. 592,552, led June 20, 1956, is also helpful for use with electrodeposited coatings.
  • Unprotected tin plated from acid electroplating baths is particularly improved by this pre-etching when in plating thickness of from 1/4 to 1 or more pounds per base box, although alkaline deposited tin plate is also improved.
  • Grain boundary etches that remove from about 50 to about 400 milligrams per square foot are very effective in providing this improvement.
  • the dichromate coating solution or dispersion can be applied by immersion, flooding, spraying, roller coating, electrostatic spraying, etc. Roller coating, immersing and ooding are particularly suitable for continuous coating of strip metal.
  • the thickness of the coating depends upon the concentration of the mixture, and if applied by roller coating, the roll pressure and roll surface characteristics also affect the thickness of the final coating.
  • a further feature of the present invention is that the pigment-containing coating dispersions generally do not need any supplemental wetting agent addition to help wet metals being treated. It appears that the pigmentcarrying dispersions with sufficient stability to hold the pigment suitably dispersed have very good wetting characteristics regardless of the metal being coated. This is even more marked where the dispersions have resin as well as pigment stably dispersed. The use of dispersions is also associated with a drop in the criticality of the pre-cleaning step.
  • the dispersing or wetting agents used to stabilize the dispersions can be of any kind.
  • long-chained alkyl sulfates are suitable and tertiary butyl alcohol will be effective although it does not cause any appreciable chemical reduction and is generally required to be in higher concentration, e.g. 0.5%,
  • anionic, cationic or non-ionic wetting agents including quaternary ammonium compounds of long-chain alkyl or aralkylamines, can be used.
  • the coatings of the present invention can also be ap'- plied to glass for the purpose of reducing its attack by etching agents such as hydrofluoric acid.
  • This feature is a great help in the manufacture of television picture tubes with glass envelopes, where the tubes have external metallic supports that are anchored to the glass envelope by means of a fritted glass block or disc fused to the envelope and providing an internally enlarged socket within which a headed-over metal arm is held.
  • the coating of the present invention to the glass frit and if desired to the adjacent portions of themetal arm, the tube envelope can be subjected to the ordinary processing involved in the conventional manufacture without having the frit attacked to the point where its ⁇ anchorage to the glass envelope is dangerously weakened.
  • Both resin-free and resin-containing coatings can be used for this purpose, and in addition, the dichromate can be replaced by chromic acid either completely ⁇ or partially. Pigments need not be used in such protective coatings although they are helpful.
  • coatings of the present invention can be used to reduce the corrosion of plain car-bon steel razor blades of the type used in shaving, for example.
  • coatings which may or may not have resin are preferably applied in relatively thin layers directly over the cutting edge of the razor.
  • a coating weight of only about 30 milligrams per square foot is adequate yfor this purpose, and such coatings are helpful in reducing somewhat the initial keeness of the edge.
  • the corrosion protection preserves the cutting edge between shaves so that it can Ibe used for at least as many shaves as unprotected edges.
  • the coatings of the present invention are also applicable ras top coatings to sharply increase the protection of metal given a preliminary coat with other types of protective material.
  • Such preliminary coatings can be of the phosphatizing type or of the oxide type, or of the standard coloring preparations such as those used for coloring zinc black.
  • the coatings can be applied to protect articles that have a temperature too high for other types of protection. Instances of such use are metal castings which can begin to oxidize after they are removed from the casting mold and during the time they cool down to room temperature. Aluminum or Zinc castings can accordingly be sprayed with the coating dispersions of the present invention when their temperatures are as high as 500 F. or even higher. These high temperatures cause the coating to be promptly cured, and when the temperature is very high can begin to decompose the coating. However, even as so decomposed, oxidation of the metal is sufliciently inhibited during the cooling process as well ⁇ as for days thereafter.
  • a small amount of resin can even be present in such coatings and no pigment need be used.
  • the proportion of ingredients is always adjusted so that at least 40% and not more than 95% of the hexavalent chromium becomes converted to trivalent chromium when the curing is completed.
  • the pigment-containing mixtures should stay within the range of 70% to 95 conversion.
  • a pigment like l0 TiO2 is particularly desirable in that it increases the ductility o-f the coating .so that it better protects metal that is subsequently drawn or pressed. Accordingly, when a green or blue color is desired, the colored pigment is advisedl-y used in combination with a liberal amount ⁇ of TiO2.
  • Example II For instance, Ithe ⁇ substitu-tion of parts of phthalocyanine green lfor an equal amount of the TiOZ gives a good green color on a product that is more fully protected in .areas that are to be deformed. The presence of the TiOz also gives the coating better hiding qualities and .as pointed out above, makes the coating harder than TiOTfree pigments do.
  • a method for simultaneously protecting and coloring a metal said method being characterized by the steps of applying to a surface of the metal ⁇ an aqueous dispersion of:
  • the reducing agent being one that causes the chromium of the dichromate to be reduced to trivalent condition when the dispersion is heated to a temperature of at least about 280 F., the concentration of the reducing agent being such that from about 70 to 95 of the chromium is so reduced, and the pigment being in a concentration of about 10 to about 75% by weight of the dichromate, and heating the metal so Icoated to a temperature between about 280 di'. and 450 F. to dry the applied dispersion and cause the above reduction, the quantity of dispersion applied to the metal being adjusted to give a coating weight after the heating of at least 100 milligrams per square foot.
  • pi-gment is selected from the class consisting of phthalocyanine pigments, TiOZ, car-bon, and iron oxide.

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US814200A 1959-05-19 1959-05-19 Metal coating Expired - Lifetime US3053702A (en)

Priority Applications (13)

Application Number Priority Date Filing Date Title
NL260637D NL260637A (enrdf_load_html_response) 1959-05-19
NL286331D NL286331A (enrdf_load_html_response) 1959-05-19
US814200A US3053702A (en) 1959-05-19 1959-05-19 Metal coating
GB15995/60A GB947315A (en) 1959-05-19 1960-05-05 Improvements in or relating to the coating of metals
DEH39465A DE1235107B (de) 1959-05-19 1960-05-18 Waesserige, Chromverbindungen und Reduktionsmittel enthaltende Auftragsloesung und Verfahren zur Herstellung farbiger korrosionsfester Schutzschichten
SE935/61A SE308234B (enrdf_load_html_response) 1959-05-19 1961-01-30
FR851259A FR1287431A (fr) 1959-05-19 1961-01-31 Procédé d'enduisage d'un métal
GB45962/62A GB1033399A (en) 1959-05-19 1962-12-05 Improvements in or relating to coatings
FR917798A FR83513E (fr) 1959-05-19 1962-12-06 Procédé d'enduisage d'un métal
DE19621444477 DE1444477A1 (de) 1959-05-19 1962-12-06 Verfahren zur Schaumminderung in waesserigen,insbesondere bindemittelhaltigen Dispersionen und zur Anwendung solcher Dispersionen
DE19621646892 DE1646892A1 (de) 1959-05-19 1962-12-06 Aus Asbest und Portlandzement bestehende Bauplatten,Ziegeln und Schindeln
BR146039/69*[A BR6346039D0 (pt) 1959-05-19 1963-01-11 Aperfeicoamentos em composicoes de revestimento e painel de cimento armado revestido com essa composicao
JP42061059A JPS501130B1 (enrdf_load_html_response) 1959-05-19 1967-09-23

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US814200A US3053702A (en) 1959-05-19 1959-05-19 Metal coating
US6021A US3128546A (en) 1960-02-01 1960-02-01 Method and flux for soldering chromium oxide coated steel members
JP4357961 1961-12-06
US222864A US3318716A (en) 1962-09-11 1962-09-11 Foam reduction and coating

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DE (2) DE1235107B (enrdf_load_html_response)
GB (2) GB947315A (enrdf_load_html_response)
NL (2) NL260637A (enrdf_load_html_response)
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3175964A (en) * 1960-01-23 1965-03-30 Yawata Iron & Steel Co Surface treatment of metal article by water-soluble (film-forming) material
US3282744A (en) * 1963-05-08 1966-11-01 Lubrizol Corp Chromate conversion coating
US3516847A (en) * 1965-02-23 1970-06-23 Pennwalt Corp Coating cementitious articles
US3999957A (en) * 1974-06-05 1976-12-28 Pennwalt Corporation Process of coating metal and resultant product
US4799959A (en) * 1984-03-26 1989-01-24 Michel Fourez Anticorrosion coating composition, process for applying it and coated threaded components
US4891268A (en) * 1984-03-26 1990-01-02 Metal Coatings International Inc. Coated metal substrates with anticorrosion coating composition
US20100261832A1 (en) * 2007-12-07 2010-10-14 Stephanie Magnet Process for the preparation of a film or a coating on a substrate with an aqueous dispersion of polymer particles and the resulting films and coatings
CN105133785A (zh) * 2015-08-18 2015-12-09 刁德斌 一种内嵌“y”型筋梁的建筑用混凝土构件

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1965269A (en) * 1931-05-01 1934-07-03 Aluminum Co Of America Method of coloring aluminum
US2163768A (en) * 1938-09-24 1939-06-27 Du Pont Chemical process
US2206064A (en) * 1936-09-16 1940-07-02 Patents Corp Metal treating process
US2210850A (en) * 1938-05-05 1940-08-06 Curtin Howe Corp Method of finishing ferrous metal surfaces
US2347572A (en) * 1940-03-11 1944-04-25 Caterpillar Tractor Co Electrocleaning process
US2442195A (en) * 1945-07-31 1948-05-25 Gen Electric Cleaning and electroplating process
US2562117A (en) * 1949-07-08 1951-07-24 Du Pont Polytetrafluoroethylene coating compositions
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
US2853406A (en) * 1956-04-17 1958-09-23 Kelsey Hayes Co Metal coating
US2902390A (en) * 1955-07-01 1959-09-01 Parker Rust Proof Co Method of coating metal surface with hexavalent chromium compound and polyacrylic acid
US2911332A (en) * 1956-05-25 1959-11-03 Kelsey Hayes Co Process of coating metal and resulting articles

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1965269A (en) * 1931-05-01 1934-07-03 Aluminum Co Of America Method of coloring aluminum
US2206064A (en) * 1936-09-16 1940-07-02 Patents Corp Metal treating process
US2210850A (en) * 1938-05-05 1940-08-06 Curtin Howe Corp Method of finishing ferrous metal surfaces
US2163768A (en) * 1938-09-24 1939-06-27 Du Pont Chemical process
US2347572A (en) * 1940-03-11 1944-04-25 Caterpillar Tractor Co Electrocleaning process
US2442195A (en) * 1945-07-31 1948-05-25 Gen Electric Cleaning and electroplating process
US2562117A (en) * 1949-07-08 1951-07-24 Du Pont Polytetrafluoroethylene coating compositions
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
US2902390A (en) * 1955-07-01 1959-09-01 Parker Rust Proof Co Method of coating metal surface with hexavalent chromium compound and polyacrylic acid
US2853406A (en) * 1956-04-17 1958-09-23 Kelsey Hayes Co Metal coating
US2911332A (en) * 1956-05-25 1959-11-03 Kelsey Hayes Co Process of coating metal and resulting articles

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3175964A (en) * 1960-01-23 1965-03-30 Yawata Iron & Steel Co Surface treatment of metal article by water-soluble (film-forming) material
US3282744A (en) * 1963-05-08 1966-11-01 Lubrizol Corp Chromate conversion coating
US3516847A (en) * 1965-02-23 1970-06-23 Pennwalt Corp Coating cementitious articles
US3999957A (en) * 1974-06-05 1976-12-28 Pennwalt Corporation Process of coating metal and resultant product
US4799959A (en) * 1984-03-26 1989-01-24 Michel Fourez Anticorrosion coating composition, process for applying it and coated threaded components
US4891268A (en) * 1984-03-26 1990-01-02 Metal Coatings International Inc. Coated metal substrates with anticorrosion coating composition
US20100261832A1 (en) * 2007-12-07 2010-10-14 Stephanie Magnet Process for the preparation of a film or a coating on a substrate with an aqueous dispersion of polymer particles and the resulting films and coatings
CN105133785A (zh) * 2015-08-18 2015-12-09 刁德斌 一种内嵌“y”型筋梁的建筑用混凝土构件

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BR6346039D0 (pt) 1973-01-11
NL260637A (enrdf_load_html_response)
GB947315A (en) 1964-01-22
NL286331A (enrdf_load_html_response)
GB1033399A (en) 1966-06-22
JPS501130B1 (enrdf_load_html_response) 1975-01-16
SE308234B (enrdf_load_html_response) 1969-02-03
DE1444477A1 (de) 1968-12-05
DE1235107B (de) 1967-02-23

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