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
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/16—Pretreatment, e.g. desmutting
• • 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
• • 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
  • C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
  • C23C2222/20—Use of solutions containing silanes
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/20—Pretreatment

Definitions

• the present invention relates to a chemical conversion treatment agent, a pre-coating treatment method, and a metal member.
• Chemical conversion treatment is usually performed for the purpose of improving properties such as corrosion resistance and coating adhesiveness when a surface of a metal material is subjected to cation electrodeposition coating, powder coating, or the like.
• Chromate treatment is commonly used for chemical conversion in view of its capability of further improving adhesion and corrosion resistance of a coated film.
• the hazardous properties of chromium however, have been noted, and thus there have been demands for developing a chemical conversion treatment agent which does not contain chromium.
• zinc phosphate treatment is widely performed for zinc phosphate treatment.
• zinc phosphate-based treatment agents contain high concentrations of metal ions and acids, and are highly reactive. This may result in poor waste-treatment economy and poor workability. Further, when a metal surface is treated with a zinc phosphate-based treatment agent, water-insoluble salts may be generated and deposited as precipitates. These precipitates are generally referred to sludge. The removal and disposal of such sludge may add undesirable costs and other problems. Further, phosphate ions may be responsible for increased environmental burden due to eutrophication, and may require additional efforts for waste treatment. Therefore, use of phosphate ions is preferably avoided. Moreover, the treatment of a metal surface with a zinc phosphate-based treatment agent requires surface conditioning. This, disadvantageously, may result in a prolonged process.
• metal-surface treatment agent other than such a zinc phosphate-based treatment agent or a chromate chemical conversion treatment agent known is a metal-surface treatment agent including a zirconium compound.
• a metal-surface treatment agent including a zirconium compound has a superior property as compared with a zinc phosphate-based chemical conversion treatment agent as described above in that the generation of sludge can be prevented.
• a chemical conversion film obtained by a metal-surface treatment agent including a zirconium compound shows poor adhesiveness, in particular with a coated film obtained by cation electrodeposition coating, and is less often used as a pre-treatment step of cation electrodeposition coating.
• a component such as phosphate ions may be used in combination for improving adhesiveness and corrosion resistance.
• phosphate ions when used in combination, the aforementioned problems such as eutrophication may occur.
• an iron-based base material treated with such a metal-surface treatment agent may have a problem in that neither sufficient coating adhesiveness nor post-coating corrosion resistance can be obtained.
• a non-chromate metal-surface treatment agent which includes a zirconium compound and an amino group-containing silane coupling agent.
• surface treatment with such a non-chromate metal-surface treatment agent as an application-type treatment agent used in the field of so-called coil coating is not comparable with post-treatment water-washing. Further, such a non-chromate metal-surface treatment agent is not intended for a target workpiece having a complicated shape.
• a pre-coating treatment method is desired to be developed, by which chemical conversion can be performed without causing any problem even in such a case.
• a pre-coating treatment method is also desired to be developed, by which chemical conversion can be performed without causing the aforementioned problems even in coating other than cation electrodeposition coating using a powder coating material, a solvent coating material, a water-based paint, and the like.
• a pre-coating treatment method involving treating a target workpiece with a chemical conversion treatment agent including at least one selected from the group consisting of zirconium, titanium, and hafnium; fluorine; and at least one selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, polymers thereof to form a chemical conversion film (for example, see Patent Document 1 below).
• a chemical conversion treatment agent including at least one selected from the group consisting of zirconium, titanium, and hafnium; fluorine; and at least one selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, polymers thereof to form a chemical conversion film
• the above pre-coating treatment method is compatible with any common coating methods, and can provide similar adhesiveness and post-coating corrosion resistance as a case where a zinc phosphate-based chemical conversion treatment agent is used.
• post-coating corrosion resistance obtained was less than satisfactory, depending on a treatment target and applications thereof.
• Patent Document 1 Japanese Unexamined Patent Application, Publication No. 2004-218070
• An object of the present invention is to provide a chemical conversion treatment agent which may cause less environmental burden, and can ensure good post-coating corrosion resistance regardless of treatment targets.
• the present invention relates to a chemical conversion treatment agent including at least one (A) selected from the group consisting of zirconium, titanium, and hafnium; at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof; fluorine (C); and a cationic urethane resin (D).
• A selected from the group consisting of zirconium, titanium, and hafnium
• B selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof
• fluorine (C) fluorine
• C a cationic urethane resin
• the total content of (A) is 20 to 10000 ppm by mass in terms of metal, and pH is 1.5 to 6.5.
• the total content of (B) is 5 to 5000 ppm by mass in the solid content concentration
• the content of (D) is 5 to 5000 ppm by mass in the solid content concentration
• the solid content mass ratio ((B)/(D)) of (B) to (D) is 0.0002 to 5000.
• At least one adhesiveness and corrosion resistance-conferring agent selected from the group consisting of magnesium ions, zinc ions, calcium ions, aluminum ions, gallium ions, indium ions, and copper ions.
• the present invention also relates to a pre-coating treatment method including treating a target workpiece with the above chemical conversion treatment agent.
• the present invention relates to a metal member treated by the above pre-coating treatment method.
• the present invention can provide a chemical conversion treatment agent which may cause less environmental burden, and can ensure good post-coating corrosion resistance regardless of treatment targets.
• a chemical conversion treatment agent according to the present embodiment can form a chemical conversion film on a metal surface as a target workpiece, and confer preferred post-coating corrosion resistance on the metal surface.
• a metal as a target workpiece
• any metals such as iron, zinc, and aluminum may be used.
• the chemical conversion treatment agent according to the present embodiment is preferably used in particular for iron-based highly high tension steel sheets and hot-rolled steel sheets. Such an iron-based highly high tension steel sheets and hot-rolled steel sheets are widely used in suspension related parts of automobiles and the like.
• a uniform chemical conversion film may be difficult to be formed on a surface thereof due to an oxide film which may be formed on the surface.
• the chemical conversion treatment agent according to the present embodiment which is substantially free of phosphate ions and hazardous heavy metal ions, can form a uniform chemical conversion film even on the surfaces of a highly high tension steel sheet and a hot-rolled steel sheet. This can ensure good post-coating corrosion resistance of a target workpiece.
• the chemical conversion treatment agent according to the present embodiment includes at least one (A) selected from the group consisting of zirconium, titanium, and hafnium; at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof; and fluorine (C); and a cationic urethane resin (D).
• the at least one (A) selected from the group consisting of zirconium, titanium, and hafnium corresponds to a component for forming a chemical conversion film. Formation of a chemical conversion film including at least one selected from the group consisting of zirconium, titanium, and hafnium on a base material can improve corrosion resistance and abrasion resistance of the base material, and further can enhance adhesiveness with a coated film.
• the chemical conversion treatment agent according to the present embodiment which is a reactive chemical conversion treatment agent, can be used even for dipping treatment of a target workpiece having a complicated shape.
• surface treatment performed with the above chemical conversion treatment agent can produce a chemical conversion film adhering firmly on a target workpiece by virtue of a chemical reaction. This also can allow post-treatment water-washing to be performed.
• a source of the above zirconium examples include, for example, alkali metal fluorozirconate such as K2ZrF6; fluorozirconate such as (NH4)2ZrF6; soluble fluorozirconate such as fluorozirconate acid such as H2ZrF6; zirconium fluoride; zirconium oxide; and the like.
• alkali metal fluorozirconate such as K2ZrF6
• fluorozirconate such as (NH4)2ZrF6
• soluble fluorozirconate such as fluorozirconate acid such as H2ZrF6
• zirconium fluoride zirconium fluoride
• zirconium oxide zirconium oxide
• a source of the above titanium includes, for example, fluorotitanate such as alkali metal fluorotitanate, (NH4)2TiF6; soluble fluorotitanate such as fluorotitanate acid such as H2TiF6; titanium fluoride; titanium oxide; and the like.
• fluorotitanate such as alkali metal fluorotitanate, (NH4)2TiF6
• soluble fluorotitanate such as fluorotitanate acid such as H2TiF6
• titanium fluoride titanium oxide
• titanium oxide titanium oxide
• a source of the above hafnium includes, for example, fluorohafnate acid such as H2HfF6; hafnium fluoride; and the like.
• a source of the at least one selected from the group consisting of zirconium, titanium, and hafnium is preferably a compound having at least one selected from the group consisting of ZrF62-, TiF62-, and HfF62- in view of high film-forming capability.
• the total content of the at least one selected from the group consisting of zirconium, titanium, and hafnium included in the chemical conversion treatment agent according to the present embodiment is preferably within a range between a lower limit of 20 ppm by mass and an upper limit of 10000 ppm by mass in terms of metal.
• a lower limit of 20 ppm by mass When the amount is less than 20 ppm by mass, the resulting chemical conversion film may have insufficient performance.
• an amount of more than 10000 ppm by mass can not provide additional effects, and is thus economically disadvantageous.
• the above lower limit is more preferably 50 ppm by mass, and even more preferably 100 ppm by mass.
• the above upper limit is more preferably 2000 ppm by mass, and even more preferably 500 ppm by mass.
• the at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof is a compound having at least one amino group in a molecule thereof and also having a siloxane bond.
• the above at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof can interact with both a chemical conversion film and a coated film. This can improve adhesiveness between them.
• the at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof is thought to act on both a metal base material and a coated film to show an effect of improving mutual adhesiveness.
• amino group-containing silane coupling agent examples thereof can include, for example, publicly known silane coupling agents such as N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-2(aminoethyl)3-aminopropyltrimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N,N-bis[(3-(trimethoxysilyl)propyl)]ethylenediamine, and the like.
• publicly known silane coupling agents such as N-2(aminoethyl)3-aminopropylmethyldime
• Hydrolysates of the above amino group-containing silane coupling agent can be prepared by conventionally known methods, for example, by a method including dissolving the above amino group-containing silane coupling agent in ion-exchanged water, and adjusting it to be acidic with any acid, and the like.
• a hydrolysate of the above amino group-containing silane coupling agent a commercially available product such as KBP-90 (Shin-Etsu Chemical Co., Ltd., Active ingredient: 32%) may also be used.
• a polymer of the above amino group-containing silane coupling agent can include, for example, commercially available products such as Sila-Ace S-330 ( ⁇ -aminopropyltriethoxysilane; Chisso Corp.), Sila-Ace S-320 (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane; Chisso Corp.).
• the total blending amount of the at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof in the chemical conversion treatment agent according to the present embodiment is preferably within a range between a lower limit of 5 ppm by mass and an upper limit of 5000 ppm by mass in terms of the solid content concentration.
• An amount of less than 5 ppm by mass can not provide sufficient coating adhesiveness.
• An amount of more than 5000 ppm by mass can not provide additional effects, and is thus economically disadvantageous.
• the above lower limit is more preferably 10 ppm by mass, and even more preferably 50 ppm by mass.
• the above upper limit is more preferably 1000 ppm by mass, and even more preferably 500 ppm by mass.
• Fluorine (C) can serve as an etching agent for a base material.
• a source of fluorine (C) can include, for example, fluorides such as hydrofluoric acid, ammonium fluoride, fluoroboric acid, ammonium hydrogen fluoride, sodium fluoride, and sodium hydrogenfluoride.
• complex fluorides include, for example, hexafluorosilicate, and specific examples thereof can include hydrosilicofluoric acid, zinc hydrofluorosilicate, manganese hydrofluorosilicate, magnesium hydrofluorosilicate, nickel hydrofluorosilicate, iron hydrofluorosilicate, calcium hydrofluorosilicate, and the like.
• the cationic urethane resin (D) will form a uniform chemical conversion film on a metal surface as a target workpiece.
• the cationic urethane resin (D) has a cationic functional group.
• Cationic functional groups include, for example, an amino group, an ammonium group, a methylamino group, an ethylamino group, a dimethylamino group, a diethylamino group, a trimethylamino group, a triethylamino group, and the like. Among these, prepared is a quaternary ammonium group.
• a polyol isocyanate components of a urethane resin of the cationic urethane resin (D), and a method of polymerization
• a urethane resin of the cationic urethane resin (D) the followings may be used: for example, commercially available products such as F2667D (DKS Co. Ltd., Effective concentration: 25%), Superflex 620 (DKS Co. Ltd., Effective concentration: 30%), and Superflex 650 (DKS Co. Ltd., Effective concentration: 26%).
• cationic urethane resin (D) alone in a chemical conversion treatment agent can not provide preferred effects such as post-coating corrosion resistance.
• a chemical conversion treatment agent in combination with the at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof, a uniform chemical conversion film can be formed on a surface of a metal surface as a target workpiece, ensuring a preferred post-coating anticorrosion properties of that metal member as a target workpiece.
• the cationic urethane resin (D) does not undergo a competing reaction with the at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof, and thus may be preferably used without inhibiting the functionality of the amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof (B).
• the blending amount of the cationic urethane resin (D) in the chemical conversion treatment agent according to the present embodiment is preferably within a range between a lower limit of 5 ppm by mass and an upper limit of 5000 ppm by mass in terms of the solid content concentration.
• An amount of less than 5 ppm by mass can not provide sufficient coating adhesiveness.
• An amount of more than 5000 ppm by mass can not provide additional effects, and is thus economically disadvantageous.
• the above lower limit is more preferably 10 ppm by mass, and even more preferably 50 ppm by mass.
• the above upper limit is more preferably 1000 ppm by mass, and even more preferably 500 ppm by mass.
• the mass ratio ((B)/(D)) of the at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof to the cationic urethane resin (D) is preferably 0.0002 to 5000.
• a mass ratio ((B)/(D)) falling within the above range can achieve preferred post-coating corrosion resistance of a target workpiece on which a chemical conversion film is formed.
• the mass ratio ((B)/(D)) is more preferably 0.01 to 100, and even more preferably 0.5 to 2.
• the chemical conversion treatment agent according to the present embodiment is substantially free of phosphate ions.
• the phrase “substantially free of phosphate ions” means that phosphate ions may be included in an amount such that they do not function as a component of a chemical conversion treatment agent.
• the chemical conversion treatment agent used in the present embodiment is substantially free of phosphate ions. Therefore, essentially no phosphorus is used which is potentially responsible for increased environmental burden. Further, generation of sludge such as iron phosphate and zinc phosphate can be prevented, which otherwise may be generated when a zinc phosphate-based treatment agent is used.
• the chemical conversion treatment agent according to the present embodiment preferably has a pH falling within a range between a lower limit of 1.5 and an upper limit of 6.5.
• a pH of lower than 1.5 may result in excessive etching, and a sufficient film can not be formed.
• a pH of more than 6.5 may result in insufficient etching, and can not provide a good film.
• the above lower limit is more preferably 2.0, and the above upper limit is more preferably 5.5.
• the above lower limit is even more preferably 2.5, and the above upper limit is even more preferably 5.0.
• an acidic compound such as nitric acid and sulfuric acid and a basic compound such as sodium hydroxide, potassium hydroxide, and ammonia may be used.
• the chemical conversion treatment agent according to the present embodiment further includes at least one selected from the group consisting of magnesium ions, zinc ions, calcium ions, aluminum ions, gallium ions, indium ions, and copper ions as an adhesiveness and corrosion resistance-conferring agent.
• at least one selected from the group consisting of magnesium ions, zinc ions, calcium ions, aluminum ions, gallium ions, indium ions, and copper ions as an adhesiveness and corrosion resistance-conferring agent.
• Inclusion of the above adhesiveness and corrosion resistance-conferring agent can provide a chemical conversion film having better adhesiveness and corrosion resistance.
• the content of the above at least one selected from the group consisting of magnesium ions, zinc ions, calcium ions, aluminum ions, gallium ions, indium ions, and copper ions is preferably within a range between a lower limit of 1 ppm by mass and an upper limit of 5000 ppm by mass.
• a lower limit of 1 ppm by mass When the above content is less than the above lower limit, sufficient effects can not be obtained. This is not preferred.
• the above content is more than the above upper limit additional effects can not be obtained. This is economically disadvantageous, and may also decrease post-coating adhesiveness.
• the above lower limit is more preferably 25 ppm by mass, and the above upper limit is more preferably 3000 ppm by mass.
• the above chemical conversion treatment agent may be used in combination with any component in addition to the above components, if needed.
• Components which can be used can include silica and the like. It is possible to increase post-coating corrosion resistance by adding such a component.
• the treatment temperature upon the above chemical conversion is preferably within a range between a lower limit of 20° C. and an upper limit of 70° C.
• the above lower limit is more preferably 30° C.
• the above upper limit is more preferably 50° C.
• the chemical conversion time for the above chemical conversion is preferably within a range between a lower limit of 5 seconds and an upper limit of 1200 seconds.
• the above lower limit is more preferably 30 seconds, and the above upper limit is more preferably 120 seconds.
• a method of conversion treatment but examples thereof can include, for example, the dipping method, the spray method, the roll coating method, and the like.
• a metal surface may be subjected to degreasing treatment, post-degreasing water-washing treatment before performing the above chemical conversion, and subjected to post-chemical conversion waster-washing treatment after the above chemical conversion.
• the above degreasing treatment may be performed in order to remove oils and stains adhering on a surface of a base material, and usually performed by dipping treatment at 30 to 55° C. for about several minutes with a degreaser such as phosphorus-free/nitrogen-free degreasing wash liquid.
• Preliminary degreasing treatment may be performed, if needed, prior to degreasing treatment.
• the above post-degreasing water-washing treatment may be conducted by performing spray treatment using a large amount of wash water once or more times in order to wash out a degreaser with water after degreasing treatment.
• the above post-chemical conversion water-washing treatment may be performed once or more times in order to avoid negative effects on adhesiveness, corrosion resistance, and the like after various subsequent coatings. In that case, the final water-washing is properly performed with pure water.
• water washing may be performed by either one of spray water-washing or dip water-washing or in combination of these.
• drying may be performed in accordance with a known method, if needed, and then various coatings may be applied.
• the pre-coating treatment method according to the present embodiment does not require surface conditioning treatment which is required in a conventionally used practical method involving treatment with a zinc phosphate-based chemical conversion treatment agent. This enables chemical conversion of a metal base material to be performed in fewer steps.
• a metal base material used in the present embodiment can include iron-based base materials, aluminum-based base materials, and zinc-based base materials.
• Iron-, aluminum-, and zinc-based base materials mean an iron-based base material in which the base material includes iron and/or an alloy thereof, an aluminum-based base material in which the base material includes aluminum and/or an alloy thereof, and a zinc-based base material in which the base material includes zinc and/or an alloy thereof, respectively.
• the pre-coating treatment method according to the present embodiment is preferably used in particular for an iron-based highly high tension steel sheet and hot-rolled steel sheet.
• An oxide film having fine surface unevenness may be formed on a hot-rolled steel sheet, and the oxide film is also of a porous state in which a large number of pores are present. For this reason, the surface is very difficult to be covered with a uniform chemical conversion film.
• An ununiform chemical conversion film formed on a surface may cause different potentials between a coated portion and an uncoated portion, preventing formation of a uniform electrodeposition coated film upon electrodeposition coating.
• a pre-coating treatment method using a conventional chemical conversion treatment agent including zirconium and others can not ensure post-coating corrosion resistance comparable to that in a case where a zinc phosphate-based chemical conversion treatment agent.
• an oxide film having fine surface unevenness may also be formed on a highly high tension steel sheet, and a large amount of dissimilar metals may also be included in the highly high tension steel sheet. These may cause the above different potentials to be more significant, resulting in even less uniform covering with a chemical conversion film. Therefore, ensuring post-coating corrosion resistance may be more difficult.
• the pre-coating treatment method according to the present embodiment can form a uniform chemical conversion film even on an iron-based highly high tension steel sheet and hot-rolled steel sheet, and can ensure post-coating corrosion resistance comparable to that in a case where a phosphate ion-containing chemical conversion treatment agent is used.
• the mechanism by which such an effect can be obtained is not clearly understood. Nonetheless, one possibility is that the cationic urethane resin (D) may preferentially cover depressed portions and pores of an oxide film through the interaction between the cationic groups of the cationic urethane resin (D) included in a chemical conversion treatment agent and a surface of a steel sheet.
• the film content of a chemical conversion film obtained by the pre-coating treatment method according to the present embodiment is preferably within a range between a lower limit of 0.1 mg/m2 and an upper limit of 500 mg/m2 in terms of the total amount of metal included in a chemical conversion treatment agent.
• An amount of less than 0.1 mg/m2 can not provide a uniform chemical conversion film, and is thus not preferred.
• An amount of more than 500 mg/m2 can not provide additional effects, and is thus economically disadvantageous.
• the above lower limit is more preferably 5 mg/m2, and the above upper limit is more preferably 200 mg/m2.
• a metal base material treated by the above pre-coating treatment method may be subjected to laser processing, press working, and the like to obtain a metal member formed and processed depending on various purposes.
• a pre-formed and processed metal member may be subjected to the above pre-coating treatment method.
• a metal member according to the present embodiment examples include metal members of automobiles such as a door, a bonnet, a roof, a hood, a fender, a trunk room, and the like. Further, they also include metal members used for motorcycles, buses, bicycles, and the like.
• a metal member treated by the pre-coating treatment method according to the present embodiment may preferably be used in those applications as described above in which a high level of post-coating corrosion resistance is required in view of safely and aesthetics.
• coating which can be performed on a metal member treated by the above pre-coating treatment method, but coating may be performed with a conventionally known coating material such as a cationic electrodeposition coating material, a solvent coating material, a water-based coating material, and a powder coating material.
• a conventionally known cationic electrodeposition coating material including an aminated epoxy resin, aminated acrylic resin, a sulfonated epoxy resin, and the like may be applied.
• a cationic electrodeposition coating material including a resin having a functional group which shows reactivity or compatibility with an amino group is preferred in order to enhance adhesiveness between an electrodeposition coated film and a chemical conversion film, considering that at least one selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof is blended in a chemical conversion treatment agent.
• the present invention shall not be limited to the above embodiments. Modifications, improvements, and the like can be made within a scope of the present invention as long as an effect of the present invention can be achieved.
• a commercially available cold-rolled steel plate (SPC 270, Nippon Testpanel Co., Ltd., 70 mm ⁇ 150 mm ⁇ 0.8 mm) as a base material was subjected to pre-coating treatment under the following conditions.
• Degreasing treatment Dipping treatment was performed at 40° C. with 2% by mass of “Surfcleaner 53” (a degreaser from Nippon Paint Surf Chemicals Co., Ltd.).
• Post-degreasing water-washing treatment Spray treatment was performed with tap water for 30 seconds.
• Chemical conversion treatment Zircon hydrofluoric acid and KBM-603 (N-2(aminoethyl)3-aminopropyltrimethoxysilane, Effective concentration: 100%, Shin-Etsu Chemical Co., Ltd.) as an amino group-containing silane coupling agent; and F2667D (DKS Co.
• a chemical conversion treatment agent including zirconium (A) in a concentration of 100 ppm by mass, an amino group-containing silane coupling agent (B) in a concentration of 100 ppm by mass in terms of the solid content, and a cationic urethane resin (D) in a concentration of 100 ppm by mass.
• Sodium hydroxide was used to adjusted pH to 4.
• the temperature of the chemical conversion treatment agent was adjusted to 40° C., and a base material was dip-treated for 60 seconds.
• the film amount in the initial stage of the treatment was 13.4 mg/m2.
• Post-chemical conversion water-washing treatment Spray treatment was performed with tap water for 30 seconds. Further, spray treatment was performed with ion-exchanged water for 10 seconds. Then, electrodeposition coating was performed in a wet condition. A cold-rolled steel sheet after water washing was dried at 80° C. for 5 minutes in an electric drying furnace, and then the film amount was analyzed as the total amount of metal contained in a chemical conversion treatment agent with a “ZSX PrimusII” (an X-ray analyzer from Rigaku Corporation).
• ZSX PrimusII an X-ray analyzer from Rigaku Corporation
• a cold-rolled steel plate was treated with a chemical conversion treatment agent at 1 L per m2, and then electrodeposition-coated with “Powernics 310” (a cationic electrodeposition coating material from Nipponpaint Industrial Coatings Co., Ltd.) so as to obtain a dry coating thickness of 20 ⁇ m, and washed with water, and then heated for baking at 170° C. for 20 minutes to obtain a test plate.
• Powernics 310 a cationic electrodeposition coating material from Nipponpaint Industrial Coatings Co., Ltd.
• Test plates were prepared as in Example 1 except that the metal base material was changed to a cold-rolled steel plate (SPC 780 from Nippon Testpanel Co., Ltd., 70 mm ⁇ 150 mm ⁇ 0.8 mm), hot-rolled steel plates (SPH 270, SPH 440, SPH 590 from Nippon Testpanel Co., Ltd., 70 mm ⁇ 150 mm ⁇ 0.8 mm), a zinc-based plated steel sheet (GA 270 from Nippon Testpanel Co., Ltd., 70 mm ⁇ 150 mm ⁇ 0.8 mm), or a 6000-series aluminum plate (Nippon Testpanel Co., Ltd., 70 mm ⁇ 150 mm ⁇ 0.8 mm).
• SPC 780 from Nippon Testpanel Co., Ltd., 70 mm ⁇ 150 mm ⁇ 0.8 mm
• hot-rolled steel plates SPH 270, SPH 440, SPH 590 from Nippon Testpanel Co., Ltd., 70 mm ⁇ 150 mm ⁇ 0.8 mm
• a zinc-based plated steel sheet GA
• SPC represents the above cold-rolled steel plate
• SPH represents the above hot-rolled steel plates
• GA represents the above zinc-based plated steel sheet
• AL represents the above 6000-series aluminum plate.
• Test plates were prepared as in Example 1 except that the above cold rolled steel plate or hot-rolled steel plates were used as a metal base material, and the concentrations of the silane coupling agent (B) and the cationic urethane resin (D) were 1 ppm by mass, 5 ppm by masses, and 50 ppm by masses, respectively as shown in Table 1.
• Test plates were prepared as in Example 1 except that the above hot-rolled steel plates were used as a metal base material, and Superflex 620 (DKS Co. Ltd., Effective concentration: 30%) or Superflex 650 (DKS Co. Ltd., Effective concentration: 26%) was used as the cationic urethane resin (D) as shown in Table 1.
• Test plates were prepared as in Example 1 except that the above cold rolled steel plate or hot-rolled steel plates were used as a metal base material, and KBM-603 (N-2(aminoethyl)3-aminopropyltrimethoxysilane, effective concentration 100%, Shin-Etsu Chemical Co., Ltd.) or KBM-903 (3-aminopropyltrimethoxysilane, effective concentration: 100%, Shin-Etsu Chemical Co., Ltd.) was used as the silane coupling agent (B) as shown in Table 1, and the concentrations of the silane coupling agent (B) and the cationic urethane resin (D) were as shown in Table 1.
• KBM-603 N-2(aminoethyl)3-aminopropyltrimethoxysilane, effective concentration 100%, Shin-Etsu Chemical Co., Ltd.
• KBM-903 3-aminopropyltrimethoxysilane, effective concentration: 100%, Shin-Etsu Chemical Co
• Test plates were prepared as in Example 1 except that the concentration of zirconium (A) was 500 ppm by masses, and the above cold-rolled steel plate or hot-rolled steel plates were used as a metal base material, and KBE-903 (3-aminopropyltriethoxysilane, effective concentration: 100%, Shin-Etsu Chemical Co., Ltd.
• silane coupling agent (B) As shown in Table 1, and the concentrations of the silane coupling agent (B) and the cationic urethane resin (D) were as shown in Table 1.
• Test plates were prepared as in Example 1 except that the above cold rolled steel plate or hot-rolled steel plates were used as a metal base material, and zinc nitrate (Zn) was used as an adhesiveness and corrosion-resistance conferring material shown in Tables 1 and 2, and the concentrations of zirconium (A), the silane coupling agent (B), and the cationic urethane resin (D) were as shown in Tables 1 and 2.
• Zn zinc nitrate
• Test plates were prepared as in Example 1 except that the above cold rolled steel plate or hot-rolled steel plates were used as a metal base material as shown in Table 2, and the concentrations of the silane coupling agent (B) and the cationic urethane resin (D) were as shown in Table 2.
• Test plates were prepared as in Example 1 except that the above cold rolled steel plate or hot-rolled steel plates were used as a metal base material as shown in Table 2, and the concentration of the silane coupling agent (B) or the cationic urethane resin (D) was as shown in Table 2.
• a test plate was prepared as in Example 1 except that a chemical conversion treatment agent was prepared without including the cationic urethane resin (D) in the chemical conversion treatment agent.
• Test plates were prepared as in Example 1 except that the above cold rolled steel plate or hot-rolled steel plates were used as a metal base material, and surface conditioning was performed with Surffine GL1 (Nippon Paint Surf Chemicals Co., Ltd.) at room temperature for 30 seconds after post-degreasing water-washing treatment, and then chemical conversion treatment was performed by dipping treatment using Surfdine SD-6350 (a zinc phosphate-based chemical conversion treatment agent from Nippon Paint Surf Chemicals Co., Ltd.) at 35° C. for 2 minutes instead of using the above chemical conversion treatment agents as shown in Table 2.
• Surffine GL1 Nippon Paint Surf Chemicals Co., Ltd.
• Surfdine SD-6350 a zinc phosphate-based chemical conversion treatment agent from Nippon Paint Surf Chemicals Co., Ltd.
• Comparison of Examples 1 to 41 with Comparative Examples 1 to 5, 7, and 8 shows that the metal base materials treated by the chemical conversion treatment agents from Examples 1 to 41 have superior secondary adhesiveness (SDT) as compared with the metal base materials treated by the chemical conversion treatment agents from Comparative Examples 1 to 5, 7, and 8.
• SDT secondary adhesiveness
• a chemical conversion treatment agent does not contain the at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof, and also indicates that preferred post-coating corrosion resistance can be conferred on a metal base material by pre-coating treatment of the metal base material with a chemical conversion treatment agent including the at least one (B) selected from the group consisting of an amino group-containing silane coupling agent, hydrolysates thereof, and polymers thereof in combination with the cationic urethane resin (D).
• Comparison of Examples 1 to 41 with Comparative Example 6 shows that the metal base materials treated with the chemical conversion treatment agents from Examples 1 to 41 have superior results from the combined cyclic corrosion tests (CCT) as compared with the metal base material treated with the chemical conversion treatment agent from Comparative Example 6. These results indicate that inclusion of the cationic urethane resin (D) in a chemical conversion treatment agent can confer preferred post-coating corrosion resistance on a metal base material treated with the chemical conversion treatment agent.
• CCT combined cyclic corrosion tests
• Comparison of Examples 1 to 41 with Reference Examples 1 to 3 shows that the metal base materials treated with the chemical conversion treatment agents from Examples 1 to 41 have comparable or superior results from the salt-water spray tests (SST), the combined cyclic corrosion tests (CCT) as compared with the metal base materials treated with the chemical conversion treatment agents from Reference Examples 1 to 3.
• SST salt-water spray tests
• CCT combined cyclic corrosion tests
• These results indicate that the metal base materials treated with the chemical conversion treatment agents according to the embodiments of the present invention have comparable or superior post-coating corrosion resistance as compared with the metal base material treated by the conventional pre-coating treatment method used for a cold-rolled steel plate from the reference example 1 and the metal base materials subjected to the conventional zinc phosphate treatment from Reference Examples 2 to 3.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Electrochemistry (AREA)
• Chemical Treatment Of Metals (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=65002567

Family Applications (1)

Country Status (4)

Family Cites Families (6)

• 2017
  • 2017-07-13 JP JP2017137368A patent/JP2019019356A/ja active Pending
• 2018
  • 2018-07-12 WO PCT/JP2018/026328 patent/WO2019013282A1/ja active Application Filing
  • 2018-07-12 CN CN201880045512.6A patent/CN110869534A/zh active Pending
  • 2018-07-12 US US16/629,484 patent/US20200165741A1/en not_active Abandoned

Also Published As

Similar Documents

Legal Events