Classifications

• • 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
  • C23C22/36—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 containing also phosphates
  • C23C22/361—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 containing also phosphates containing titanium, zirconium or hafnium compounds

Definitions

• This invention relates to a novel composition and method for treating the surfaces of aluminiferous metals, defined as aluminum and aluminum alloys which contain at least 45 % by weight of aluminum, in order thereby to provide such metal surfaces prior to their painting with an excellent corrosion resistance and paint adherence.
• This invention may be applied with particularly good ef ⁇ fects to the surface treatment of aluminum drawn-and-ironed (hereinafter usually abbreviated "Dl”) can stock.
• Dl aluminum drawn-and-ironed
• the surface treat- ment composition and method according to the present invention are able to provide the surface of the can, prior to the painting or printing thereof, with an ex ⁇ cellent corrosion resistance and paint adherence in a much shorter period of time than in prior art methods.
• Background Art Baths for treating the surface of aluminiferous metals may be broadly clas ⁇ sified into chromate-type treatment baths and non-chromate-type treatment baths.
• the chromate-type treatment baths typically occur as chromic acid chro- mate conversion treatment baths and phosphoric acid chromate conversion treat ⁇ ment baths.
• Chromic acid chromate conversion treatment baths were first util- ized in about 1950 and are in wide use even at present, for example, for heat ex ⁇ changer fins and the like. Chromic acid chromate conversion treatment baths contain chromic acid (CrO 3 ) and hydrofluoric acid (HF) as their base compon ⁇ ents, and may contain a conversion accelerator as desired. These baths form a conversion coating on the metal surface that contains small amounts of hexa- valent chromium.
• CrO 3 chromic acid
• HF hydrofluoric acid
• the phosphoric acid chromate conversion treatment bath was invented in 1945 (United States Patent Number 2,438,877). This conversion bath con ⁇ tains chromic acid (CrO 3 ), phosphoric acid (H 3 PO 4 ), and hydrofluoric acid (HF) as its base components.
• the main component in the coating produced by this bath is hydrated chromium phosphate (CrPO 4 *4H 2 O). Since this conversion coating does not contain hexavalent chromium, this bath is also in wide use at present as, for example, a paint undercoat treatment for the lid and body of bev ⁇ erage cans.
• the above-described chromate-type surface treatment baths contain toxic hexavalent chromium, but environmental considerations make it desirable to use hexavalent chromium-free treatment baths.
• the treatment bath taught in Japan ⁇ ese Patent Application Laid Open [Kokai or Unexamined] Number Sho 52- 131937 [131,937/1977] is typical of inventions relating to non-chromate-type (chromium-free) surface treatment baths.
• Non-chromate-type treatment baths are currently widely used for alumin ⁇ um Dl cans because they offer the advantage of being free of hexavalent chromi ⁇ um, although treatment times of at least 15 seconds are required with these baths in order to obtain an industrially satisfactory performance (corrosion resist ⁇ ance).
• corrosion resist ⁇ ance a corrosion resist ⁇ ance
• This method does not afford an indus ⁇ trially satisfactory blackening resistance.
• a non-chromate treatment method is disclosed in Japanese Patent Publi ⁇ cation Number Sho 57-39314 [39,314/1982].
• the surface of aluminiferous metal is treated with an acidic solution containing titanium salt and/ or zirconium salt, hydrogen peroxide, and phosphoric acid and/or condensed phosphoric acid.
• This treatment bath is, however, unstable, and it also exhibits an unsatisfactory reactivity in terms of surface film formation. Nor does this dis ⁇ closure specifically describe the treatment temperature, treatment time, or treat ⁇ ment process. Finally, it is difficult to obtain an industrially stable blackening re ⁇ sistance using the method disclosed in Japanese Patent Publication Number Sho 57-39314. Disclosure of the Invention
• the present invention seeks to solve the problems described above for the prior art.
• the present invention introduces a stable compo ⁇ sition for treating the surface of aluminiferous metals that is able to rapidly impart an excellent corrosion resistance and paint adherence to the surface of aluminif ⁇ erous metals.
• This invention also introduces a surface treatment method that uses said composition.
• a very corrosion-resistant and high- ly paint-adherent coating could be rapidly formed on the surface of aluminiferous metal by execution of a surface treatment method comprising (a) contacting the aluminiferous metal surface, preferably at 30° C to 50° C, with an aqueous surface treatment composition, also called a "bath" for brevity even though it can be used for spraying as well as immersion, said bath comprising, preferably consisting essentially of, or more preferably consisting of, water and a mixture in specific proportions of phosphate ions, zirconium compound, fluoride, and oxi- dant, (b) then rinsing the treatment bath-bearing surface of the metal with water, and (c) drying by heating.
• a surface treatment method comprising (a) contacting the aluminiferous metal surface, preferably at 30° C to 50° C, with an aqueous surface treatment composition, also called a "bath" for brevity even though it can be used for
• the bath according to the present invention for treating the surface of aluminiferous metals characteristically comprises 1 to 80 parts by weight (here- inafter usually abbreviated "pbw") of phosphate ions, zirconium compound at 1 to 15 pbw as zirconium atoms, fluoride at 3 to 100 pbw as fluorine atoms, and 1 to 100 pbw of oxidant.
• pbw parts by weight
• the method according to the present invention for treating the surface of aluminiferous metals characteristically comprises contacting the surface of alum- iniferous metal for 2 to 30 seconds at 30° C to 50° C with a surface treatment bath containing the above-described surface treatment composition, then rinsing the treated metal surface with water, and thereafter drying by heating.
• the surface treatment composition according to the present invention is an acidic aqueous treatment bath whose essential ingredient is a mixture of phosphate ions, zirconium compound, fluoride, and oxidant.
• ⁇ ance is the joint use of fluoride and oxidant in the surface treatment composition according to the present invention and the surface treatment bath used by the surface treatment method according to the present invention.
• This joint use of fluoride and oxidant has the surprising effects of stabilizing the surface treatment bath and inducing a substantial improvement in both the corrosion resistance (re ⁇ sistance to blackening) and paint adherence of the resulting surface coating.
• the surface treatment composition according to the present invention is an aqueous bath of a mixture that contains the following components in the fol ⁇ lowing weight proportions: phosphate ions 1 - 80 pbw zirconium compound (as zirconium atoms) 1 - 15 pbw fluoride (as fluorine atoms) 3 - 100 pbw oxidant 1 - 100 pbw
• phosphate ions 0.01 - 0.8 g/L zirconium compound (as zirconium atoms) 0.01 - 0.15 g/L fluoride (as fluorine atoms) 0.03 - 1 g/L oxidant 0.01 - 1 g/L
• the pH of this surface treatment bath is preferably adjusted into the range from 2.0 to 4.0.
• Phosphoric acid H 3 PO 4
• its salts, and the like can be used to introduce phosphate ions into the surface treatment composition according to the present invention.
• the phosphate ions content in the above-described component recipe for the surface treatment composition according to the present invention ranges from 1 to 80 pbw, while the preferred range is from 3 to 20 pbw.
• the corre ⁇ sponding surface treatment bath is poorly reactive and good film formation does not usually occur when the phosphate ions content in the above-described com ⁇ ponent recipe ' falls below 1 pbw.
• the source of the zirconium compound in the surface treatment composi ⁇ tion according to the present invention is not critical, and the oxides, hydroxides, nitrates, fluorides, and the like of zirconium can be used as the zirconium com ⁇ pound source.
• the zirconium compound content in the above-described com ⁇ ponent recipe for the surface treatment composition according to the present in- vention ranges from 1 to 15 pbw as zirconium atoms, while the preferred zircon ⁇ ium compound content ranges from 4 to 8 pbw as zirconium atoms.
• the cor ⁇ responding surface treatment bath will not form a good-quality film when the zir- conium content falls below 1 weight part. The quality of the film no longer im ⁇ proves at amounts in excess of 15 pbw and such levels are therefore uneconom ⁇ ical since they serve only to raise the cost of the treatment bath.
• the fluoride source for the surface treatment composition according to the present invention is not critical, and acids such as hydrofluoric acid (HF), fluozir- conic acid (H 2 ZrF 6 ), fluotitanic acid (H 2 TiF 6 ), fluosilicic acid, fluoboric acid, and the like, and the salts of these acids may be used as the fluoride source.
• acids such as hydrofluoric acid (HF), fluozir- conic acid (H 2 ZrF 6 ), fluotitanic acid (H 2 TiF 6 ), fluosilicic acid, fluoboric acid, and the like, and the salts of these acids may be used as the fluoride source.
• the fluoride content in the above-described component recipe for the surface treat ⁇ ment composition according to the present invention ranges from 3 to 100 pbw as fluorine atoms.
• the preferred fluoride content ranges from 3 to 60 pbw as fluorine atoms.
• the corresponding surface treatment bath is poorly reactive and good film formation does not occur when the fluoride content falls below 3 pbw.
• the use of amounts in excess of 100 pbw is undesirable because the corre ⁇ sponding increase in metal etching causes a degraded appearance.
• the treat- ment bath requires the presence of the fluoride in order to stabilize — as alumin ⁇ um fluoride — the aluminum that elutes into the treatment bath.
• the optimal fluoride content in the surface treatment bath used by the method of the present invention will vary as a function of the concentration of aluminum eluting from the metal workpiece.
• the fluorine concentration must be approximately 0.2 g/L when the aluminum concentration in the surface treatment bath is 0.1 g/L.
• the type of oxidant in the surface treatment composition according to the present invention is not critical.
• Useable oxidants include hydrogen peroxide; acids such as nitrous acid, tungstic acid, molybdic acid, peroxo acids such as peroxophosphoric acid, etc.; salts of the preceding acids; and the like.
• Hydrogen peroxide is the most preferred oxidant based on the ease of waste water treat ⁇ ment after use of a surface treatment bath containing subject composition.
• the function of the oxidant in the surface treatment composition and treatment meth ⁇ od according to the present invention is to accelerate the reaction rate for zirconi- urn film formation on the metal surface.
• the oxidant content in the above-de ⁇ scribed component recipe for the surface treatment composition according to the present invention ranges from 1 to 100 pbw.
• the preferred oxidant content rang- es from 20 to 50 pbw.
• the oxidant content is less than 1 pbw, the above- described reaction accelerating activity will not be observed when surface treat ⁇ ment is carried out using the corresponding surface treatment bath.
• no technical problems are associated with levels in excess of 100 pbw, the effect of this component is saturated at such levels and they are therefore uneconomical, because they serve only to raise the cost of the treatment bath.
• the general range for the pH of the surface treatment composition accord ⁇ ing to the present invention is 1.0 to 4.0.
• the surface treatment bath used by the method according to the present invention preferably has a pH of 2.0 to 4.0. pH values below 2.0 often cause an excessive etch of the metal surface and can im ⁇ pede formation of the conversion film. Values in excess of 4.0 will in some cases impede the formation of a highly corrosion-resistant film.
• the range of 2.3 to 3.0 is an even more preferred pH range for the surface treatment bath used in the method according to the present invention.
• the pH of the surface treatment bath can be adjusted in the method according to the present invention through the use of acids, such as phosphoric acid, nitric acid, hydrochloric acid, hydrofluoric acid, etc., or through the use of alkali, such as sodium hydroxide, sodium carbonate, ammonium hydroxide, etc.
• acids such as phosphoric acid, nitric acid, hydrochloric acid, hydrofluoric acid, etc.
• alkali such as sodium hydroxide, sodium carbonate, ammonium hydroxide, etc.
• the stability of the treatment bath can be substantially impaired by elution into the surface treatment bath of metal ions deriving from the copper, manganese, etc., compon ⁇ ent of the aluminum alloy.
• an organic acid such as glu- conic acid, oxalic acid, etc., may be added to the surface treatment bath in order to chelate this metal alloying component.
• the details of the surface treatment method according to the present in ⁇ vention will now be explained.
• the method according to the present invention uses a surface treatment bath according to the present invention.
• the sur ⁇ face treatment bath takes the form of a concentrate, it is diluted with water to the desired concentration prior to use in the method according to the present inven ⁇ tion.
• Contact between the metal and surface treatment bath preferably is car ⁇ ried out at 35° C to 50° C in the surface treatment method according to the pres- ent invention.
• Contact temperatures below 35° C sometimes result in inadequate reaction between the metal surface and treatment bath, which prevents the formation of a good-quality film.
• the zirconium compound in the treatment bath may become unstable at temperatures above 50° C, with the undesirable result that a portion of the zirconium compound will precipitate.
• the method according to the present invention can be executed by im ⁇ mersing the metal in the surface treatment bath, in which case the immersion treatment time preferably should be 2 to 30 seconds. Immersion times below 2 seconds usually result in inadequate reaction between the treatment bath and metal surface, which prevents the formation of a film with good corrosion resist- ance. Immersion times in excess of 30 seconds do not normally yield any addi ⁇ tional improvements in the properties of the resulting conversion coatings.
• preferred immersion treatment times range from 2 to 30 seconds, while immer ⁇ sion times ranging from 5 to 15 seconds are more particularly preferred.
• Contact may also be executed in the method according to the present in- vention by spraying the treatment bath onto the metal surface.
• the occurrence of a pH increase in the vicinity of the interface with the metal surface may be ⁇ come problematic when spray treatment is carried out by continuously spraying the treatment bath, and in some cases a satisfactory film formation will not occur. It is for this reason that use of an intermittent spray is preferred.
• Said intermittent spraying preferably consists of at least two sprays separated by an interval of 1 to 5 seconds.
• the surface treatment bath/metal surface contact time (sum of the spray and non-spray time intervals) in this case should again range from 2 to 30 seconds. Contact times below 2 seconds often result in an inadequate reaction and prevent the formation of a film with good corrosion resistance. No additional improvement in performance is normally obtained for contact times in excess of 30 seconds.
• Spraying at least twice with separation by an interval of 2 to 3 sec- onds is a particularly preferred technique, and the preferred overall contact time is 5 to 10 seconds.
• the add-on of the surface coating formed on aluminiferous metal by the invention method is preferably 7 to 18 mg/m 2 as zirconium.
• An inadequate corro ⁇ sion resistance by the resulting surface coating may result when the surface coating weight is less than 7 mg/m 2 as zirconium.
• the paint adherence of the re ⁇ sulting surface coating will in some cases be unsatisfactory when the surface coating weight exceeds 18 mg/m 2 as zirconium.
• the aluminiferous metals whose surface may be treated by the invention method encompass aluminum and aluminum alloys, wherein the aluminum alloys are exemplified by Al-Mn alloys, Al-Mg alloys, Al-Si alloys, and the like.
• the aluminiferous metal that may be subjected to the invention method is not specifically restricted with respect to shape or dimensions, and, for examp ⁇ le, sheet, various types of moldings, and the like may be subjected to the method according to the present invention.
• the surface treatment composition and surface treatment method accord ⁇ ing to the present invention are further illustrated by the following working examp ⁇ les, and the benefits of the invention may be further appreciated by comparison to the comparison examples.
• Aluminum Dl can (fabricated by the Dl processing of aluminum sheet) was cleaned with a hot aqueous solution of an acidic degreaser (PALKLINTM 500, registered trademark of Nihon Parkerizing Company, Limited) and then subjected to surface treatment.
• PALKLINTM 500 registered trademark of Nihon Parkerizing Company, Limited
• peel strength values in this test are indicative of a better paint adherence by the surface-treat ⁇ ed aluminum can, and peel strength values equal to or greater than 4.0 kilo ⁇ grams-force per 5 millimeters of width (hereinafter usually abbreviated "kgf/ 5mm") are generally regarded as satisfactory for practical applications.
• Example 1 A cleaned aluminum Dl can as described above was sprayed with surface treatment bath 1 (with a composition given below) heated to 40° C. This spray treatment consisted of 3 sprays (2 seconds each) separated by 3 second inter- vals (for a total of 12 seconds). The treated surface was then rinsed with tap water and thereafter sprayed for 10 seconds with de-ionized water (with a resis ⁇ tivity of at least 3,000,000 ohm-cm). The aluminum Dl can was subsequently dried in a hot-air drying oven at 180° C for 2 minutes and submitted to evaluation of the corrosion resistance and paint adherence.
• surface treatment bath 1 with a composition given below
• ppm Composition of surface treatment bath 1
• ppm hereinafter means parts per million by weight
• 75 % phosphoric acid (H 3 PO 4 ) 75 % phosphoric acid (H 3 PO 4 ) 69 ppm (PO ons: 50 ppm)
• a cleaned aluminum Dl can was immersed for 15 seconds in surface treatment bath 2 (with a composition given below) heated to 50° C.
• the Dl can was removed from the surface treatment bath and then rinsed with water, rinsed with deionized water, and dried according to the procedure in Example 1.
• the resulting Dl can was submitted to evaluation of the corrosion resistance and paint adherence.
• Example 3 A cleaned aluminum Dl can was sprayed with surface treatment bath 3 (with a composition given below) heated to 50° C. This spray treatment consist ⁇ ed of 2 sprays (2 seconds each) separated by a 1 second interval (total of 5 sec ⁇ onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 3
• Example 4 A cleaned aluminum Dl can was sprayed with surface treatment bath 4
• Example 5 A cleaned aluminum Dl can was sprayed with surface treatment bath 5 (with a composition given below) heated to 35° C. This spray treatment consist ⁇ ed of 3 sprays (2 seconds each) separated by 2 second intervals (total of 10 sec ⁇ onds). This was followed by rinsing with water, rinsing with deionized water a d drying according to the procedure in Example 1. The resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 5
• Example 6 A cleaned aluminum Dl can was sprayed with surface treatment bath 6 (with a composition given below) heated to 35° C. This spray treatment consist ⁇ ed of 3 sprays (3 seconds each) separated by 5 second intervals (total of 19 sec ⁇ onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 6
• Example 7 A cleaned aluminum Dl can was sprayed with surface treatment bath 7 (with a composition given below) heated to 35° C. This spray treatment consist ⁇ ed of 4 sprays (2 seconds each) separated by 2 second intervals (total of 14 sec ⁇ onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 7
• Example 8 A cleaned aluminum Dl can was sprayed with surface treatment bath 8 (with a composition given below) heated to 35° C. This spray treatment consist ⁇ ed of 3 sprays (2 seconds each) separated by 2 second intervals (total of 10 sec- onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 8
• Exxaammpplle 9 A cleaned aluminum Dl can was sprayed with surface treatment bath 9 (with a composition given below) heated to 35° C. This spray treatment consist ⁇ ed of 3 sprays (2 seconds each) separated by 2 second intervals (total of 10 sec ⁇ onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence.
• composition of surface treatment bath 9 75 % phosphoric acid (H 3 PO 4 ) 25 ppm (PO 4 ions: 18 ppm) 20% fluozirconic acid (H 2 ZrF 6 ) 228 ppm (Zr: 20 ppm) 20 % hydrofluoric acid (HF) 150 ppm (F: 54 ppm) 30 % hydrogen peroxide (H 2 O 2 ) 667 ppm (H 2 O 2 : 200 ppm) pH: 2.5 (adjusted with aqueous ammonia)
• Example 10 A cleaned aluminum Dl can was sprayed with surface treatment bath 10 (with a composition given below) heated to 35° C. This spray treatment consist ⁇ ed of 7 sprays (2 seconds each) separated by 2 second intervals (total of 30 sec- onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 10 75 % phosphoric acid (H 3 PO 4 ) 14 ppm (PO 4 ions: 10 ppm) 20 % fluozirconic acid (H 2 ZrF 6 ) 114 ppm (Zr: 10 ppm)
• Example 11 A cleaned aluminum Dl can was sprayed with surface treatment bath 11 (with a composition given below) heated to 35° C. This spray treatment consist- ed of a 3-second spray (total of 3 seconds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Ex ⁇ ample 1. The resulting Dl can was subjected to evaluation of the corrosion re ⁇ sistance and paint adherence.
• Composition of surface treatment bath 11 75 % phosphoric acid (H 3 PO 4 ) 413 ppm (PO 4 : 300 ppm)
• a cleaned aluminum Dl can was sprayed with surface treatment bath 12 (with a composition given below) heated to 35° C.
• This spray treatment consist ⁇ ed of 3 sprays (2 seconds each) separated by 2 second intervals (total of 10 sec ⁇ onds).
• the resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence.
• Comparative Example 2 A cleaned aluminum Dl can was sprayed with surface treatment bath 13 (with a composition given below) heated to 35° C. This spray treatment consist- ed of 3 sprays (2 seconds each) separated by 2 second intervals (total of 10 sec ⁇ onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub- jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 13 (with a composition given below) heated to 35° C. This spray treatment consist- ed of 3 sprays (2 seconds each) separated by 2 second intervals (total of 10 sec ⁇ onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub- jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 13
• Comparative Example 3 A cleaned aluminum Dl can was sprayed with surface treatment bath 14 (with a composition given below) heated to 35° C. This spray treatment consist- ed of 3 sprays (2 seconds each) separated by 2 second intervals (total of 10 sec ⁇ onds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was sub ⁇ jected to evaluation of the corrosion resistance and paint adherence. Composition of surface treatment bath 14 20 % fluozirconic acid (H 2 ZrF 6 ) 500 ppm (Zr: 44 ppm)
• Comparative Example 4 A cleaned aluminum Dl can was sprayed with a commercial aluminum Dl can surface treatment bath (ALODINETM 404, registered trademark of Nihon Par ⁇ kerizing Company, Limited) heated to 30° C. This spray treatment consisted of 3 sprays (2 seconds each) separated by 2 second intervals (total of 10 seconds). This was followed by rinsing with water, rinsing with deionized water, and drying according to the procedure in Example 1. The resulting Dl can was subjected to evaluation of the corrosion resistance and paint adherence.
• a commercial aluminum Dl can surface treatment bath ALODINETM 404, registered trademark of Nihon Par ⁇ kerizing Company, Limited
• the surface treatment bath according to the present invention When applied to aluminum Dl cans, the surface treatment bath according to the present invention rapidly produces a very corrosion-resistant and paint-adherent coating on the surface of aluminum Dl cans prior to its painting or printing. This makes it possi ⁇ ble to speed up the manufacturing line and reduce the size requirements (space economization) of the treatment installation.
• both the bath and method according to the present invention for treating the surface of aluminiferous metals have a very high practical utility.

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• 1994
  • 1994-12-12 JP JP6307639A patent/JP2828409B2/ja not_active Expired - Fee Related
• 1995
  • 1995-03-21 AU AU21201/95A patent/AU684929B2/en not_active Ceased
  • 1995-03-21 MX MXPA96004196A patent/MXPA96004196A/es unknown
  • 1995-03-21 CA CA 2186025 patent/CA2186025A1/en not_active Abandoned
  • 1995-03-21 EP EP95914039A patent/EP0754250A4/en not_active Withdrawn
  • 1995-03-21 WO PCT/US1995/003192 patent/WO1995025831A1/en not_active Application Discontinuation
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