WO2001006036A1 - Traitement de métaux à l'acyloxy-silane - Google Patents

Traitement de métaux à l'acyloxy-silane Download PDF

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Publication number
WO2001006036A1
WO2001006036A1 PCT/US2000/019646 US0019646W WO0106036A1 WO 2001006036 A1 WO2001006036 A1 WO 2001006036A1 US 0019646 W US0019646 W US 0019646W WO 0106036 A1 WO0106036 A1 WO 0106036A1
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WIPO (PCT)
Prior art keywords
group
acyloxy
substituted
silane
groups
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PCT/US2000/019646
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English (en)
Inventor
Wim J. Van Ooij
Danqing Zhu
Original Assignee
University Of Cincinnati
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Priority claimed from US09/356,926 external-priority patent/US6827981B2/en
Application filed by University Of Cincinnati filed Critical University Of Cincinnati
Priority to AT00948777T priority Critical patent/ATE310108T1/de
Priority to EP00948777A priority patent/EP1198616B1/fr
Priority to AU62225/00A priority patent/AU766638B2/en
Priority to CA002378851A priority patent/CA2378851A1/fr
Priority to US10/031,731 priority patent/US6955728B1/en
Priority to DE60024094T priority patent/DE60024094T2/de
Publication of WO2001006036A1 publication Critical patent/WO2001006036A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/48—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 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
    • C23C22/53—Treatment of zinc or alloys based thereon
    • 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
    • C23C22/48—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 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
    • 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
    • C23C22/48—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 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
    • C23C22/56—Treatment of aluminium or alloys based thereon
    • 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
    • C23C22/60—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 alkaline aqueous solutions with pH greater than 8
    • 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
    • C23C22/68—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 solutions with pH between 6 and 8
    • 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

Definitions

  • the present invention relates to silane coatings for metals More particularly, the present invention provides coatings which include an acyloxy silane. and are particularly useful for preventing corrosion and/or promoting adhesion between a metal substrate and a polymer layer applied to the treated metal substrate Solutions for applying such coatings, compositions as well as methods of treating metal surfaces, are also provided.
  • metallic coated steel sheet such as galvanized steel is used in many industries, including the automotive, construction and appliance industries In most cases, the galvanized steel is painted or otherwise coated with a polymer layer to achieve a durable and aesthetically-pleasing product. Galvanized steel, particularly hot-dipped galvanized steel, however, often develops "white rust" during storage and shipment.
  • White rust also called “wet-storage stain” is typically caused by moisture condensation on the surface of galvanized steel which reacts with the zinc coating.
  • the wet-storage stain is black in color (“black rust")
  • White rust (as well as black rust) is aesthetically unappealing and impairs the ability of the galvanized steel TO be painted or otherwise coated with a polymer.
  • black rust white rust
  • white rust is aesthetically unappealing and impairs the ability of the galvanized steel TO be painted or otherwise coated with a polymer.
  • the surface of the galvanized steel must be pretreated m order to remove the white rust and prevent its reformation beneath the polymer layer.
  • Various methods are currently employed to not only prevent the formation of white rust during shipment and storage, but also to prevent the formation of white rust beneath a polymer coating (e g., paint)
  • the surface of the steel is often passivated by forming a thin chromate film on the surface of the steel. While such chromate coatings do provide resistance to the formation of white rust, chromium is higniy toxic ana environmentally undesirable It is also known to employ a phosphate conversion coating in conjunction with a chromate rinse in orde ⁇ o improve paint adherence and provide corrosion protection. It is believed that the chromate rmse covers the pores in the phosphate coating, thereby improving the corrosion resistance and adhesion performance. Once again, however, it is highly desiraole to eliminate the use of chromate altogether Unfortunately, however, the phosphate conversion coating is generally not very effective without the chromate ⁇ nse.
  • U S Patent No. 5,292,549 teaches the rinsing of metallic coated steel sheet with a solution containing an organofunctional silane and a crosslmking agent
  • U.S. Patent No 6,071 ,566 relates to a method of treating a metal substrate to provide permanent corrosion resistance
  • the method comprises applying a solution containing one or more vinyl silanes in admixture with one or more muiti-silyi-functional silanes to a metal substrate in order to form a coating
  • Various other techniques for preventing the formation of white rust on galvanized steel, as well as preventing corrosion on other types of metals have also been proposed. Many of the proposed techniques described in the prior art are, however, ineffective, or require time-consuming, energy-inefficient, multi- step processes. Thus, there is a need for a simple, low-cost technique for preventing corrosion on the surface of metal
  • a particular problem associated with the silane treatments of the prior art is the rate of hydrolysis of the silane compounds.
  • Such compounds are generally hydrolysed in water, at a specific pH, prior to application of the solution to the substrate to De treated.
  • the rate of hydrolysis varies between silanes, and the degree of hydrolysis is a priori not known Generally, it has to be guessed when the solution is ready for application When the solution has turned cloudy this indicates that condensation of the silanes has occurred and the effectiveness of the treatment solution is reduced
  • a further problem with the prior an techniques is the inherent insolubility in aqueous media of some of the silanes employed in the metal treatments.
  • metal surfaces For example, steel, aluminium, aluminium alloys, zinc, zinc alloys, magnesium, magnesium alloys, copper, copper alloys, tin and tin alloys, particularly zinc, zinc alloys, and other metals having a zmc-containmg coating thereon
  • the present invention provides a method of treating a metal surface, comprising the steps of. (a) providing a metal substrate; and
  • acyloxy silane and the basic compound are present in concentrations to provide a solution pH of between about 3 and about 10, more preferably between about 4 and about 8, most preferably 4 to 5 and wherein the solution is substantially free of acid other than acid produced upon hydrolysis of the acyloxy silane.
  • the present invention also provides a composition comprising at least one acyloxy silane and at least one basic compound, wherein the at least one acyloxy silane is at least partially hydrolyzed.
  • a metal surface having improved corrosion resistance and/or adhesion and a composition concentrate is also provided.
  • the acyloxy silane(s) utilised in the present invention may comprise one or more silyl groups and the solution may contain a mixture of acyloxy silanes
  • the acyloxy silane comprises a single silyl group the silicon atom is tetrasubstituted, wherein the substituents are individually selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, alkaryl, aralkyl, vinyl, ammo, ureido, gly ⁇ doxy, epoxy, hydroxy, alkoxy, aryloxy and acyloxy, or any of the group alkyl, alkenyl, alkynyl, aryl, alkaryl and aralkyl substituted by a group selected from the group consisting of vinyl, amine, ureido, glycidoxy, epoxy, hydroxy and alkoxy, with the proviso that at least one of the substituents on the silicon atom is an acyloxy group
  • tne acyloxy groups are preferably ail the same
  • the acyloxy group(s) are preferably selected from the group consisting of C 2-12 aikanoyloxy, C 3 . l2 alkenoyioxy, C 3 . 12 alkynoyloxy and C 7 _ 1 ⁇ arenoyloxy, preferably C 2.6 aikanoyloxy, C 3-5 alkenoyioxy, C 3 ⁇ alkynoyloxy and C 7.12 arenoyloxy.
  • the acyloxy groups are all the same and are ethanoyioxy (acetoxy) or methanoyloxy groups.
  • acyloxy silane comprises a single silyl group
  • three of the substituents on the silyl group are acyloxy groups and the fourth substituent is preferably selected from a the group consisting of vinyl or vmyl substituted group, amine or amine substituted group, ureido or ureido substitute ⁇ group and glycidoxy or glycidoxy substituted group.
  • the acyloxy silane is selected from the group consisting of
  • W, X, Y and Z are selected from the group consisting of a C-Si bond, substituted aliphatic groups, unsubstituted aliphatic groups, substituted aromatic groups and unsubstituted aromatic groups, and R is selected from methyl, ethyl and propyl, preferably ethyl.
  • the acyloxy silane may comprises more than one silyl group.
  • acyloxy silane genencally refers to such a compound, it may be referred to as a multi-silyl-acyloxy silane. More than one multi-silyl-acyloxy silane may be employed in a mixture with one or more other multi-silyl-acyloxy silanes or one or more acyloxy silanes containing a single silyl group as described above
  • the acyloxy groups bound to the silicon atoms of the silyl groups of the multi-silyl-acyloxy silane are preferably all the same and are preferably selecte ⁇ from the group consisting of C 2 . 12 aikanoyloxy, C 3 . 12 alkenoyioxy, C 3 . 12 alkynoyloxy and C 7-1 ⁇ arenoyloxy, preferably C 2 _e aikanoyloxy, C 3 . 6 alkenoyioxy, C 3 . 6 alkynoyloxy and C 7 . 12 arenoyloxy.
  • the acyloxy groups are all the same and are ethanoyioxy or methanoyloxy groups
  • the multi-silyl-acyloxy silane utilised in the present invention has the structure
  • Q is selected from the group consisting of either a bond, an aliphatic or aromatic group
  • R 1 is selected from methyl, ethyl and propyl.
  • Q is selected from the group consisting of a bond. alkylene, C 2 -C 6 alkenyiene, C,-C 6 alkylene substituted with at least one ammo group, C;,-C 6 alkenyiene substituted with at least one ammo group, C C 6 alkylene substituted with at least one sulfide group containing 1 to 6 sulfur atoms, C 2 -C 6 alkenyiene substituted with at least one sulfide group containing 1 to 6 sulfur atoms, arylene and alkyiarylene.
  • the multi-functional silane comprises two t ⁇ substituted silyl groups which are bonded directly to one another.
  • Preferred multi-silyl-acyloxy silane are b ⁇ s-(t ⁇ acetoxys ⁇ lyl)alkane, bis-(tr ⁇ acetoxys ⁇ lylalkyl)amine and bis-(triacetoxys ⁇ lylalkyl)tetrasulfide, most preferably bis-(triacetoxys ⁇ lyl)ethane, b ⁇ s-(triacetoxysilylpropyl)am ⁇ ne and bis-(tnacetoxysilyipropyl)tetrasulfide.
  • the acyloxy silane utilised in the present invention is vinyltnacetoxysilane
  • Acyloxy silanes utilised in the present invention generally dissolve and hydrolyze readily and completely in water to produce organic acids. For example, where an acetoxy siiane is used, acetic acid is produced. Unlike the analogous alkoxy silanes commonly utilised in the prior art which produce alcohols upon hydrolysis, the acyloxy silanes utilised in the present invention produce substantially none or small amounts of VOCs depending on the level of no ⁇ -acyloxy group substitution in the silanes.
  • the pH of the resultant solution can be predetermined and manipulated
  • high degrees of acyloxy group substitution are present, for example -100% substitution, and this can result in a pH as low as 1 or 2
  • the hydrolysed acyloxysilanes tend to condense, therefore reducing their efficacy. It is therefore necessary to add a base to maintain the pH in an optimal range.
  • acyloxy silane 3 of the groups attached to the silicon atom of the silyl group are acyloxy groups, preferably methanoyloxy or acetoxy
  • 3 of the groups attached to the each silicon atom of each silyl group are acyloxy groups, preferably methanoyloxy or acetoxy.
  • the pH of the silane mixture is between about 3 and about 10, more preferably between about 4 and about 8, most preferably 4 to 5 and should be maintained
  • the pH may be adjusted by the addition of one or more basic compounds or addition of acyloxy silane(s).
  • a pH of above 2, more preferably above 3, most preferably between 4 and 5 should be maintained
  • a basic compound is applied to the treatment solution.
  • the identity of the basic compound(s) is not critical but it is highly beneficial to provide a compound which complements the acyloxy silane "Complements" means that the basic compound aids, or at least does not substantially detract from the formation of the silane coating on the metal substrate or from the coatings effectiveness m improving corrosion resistance and/or adhesion promotion.
  • the acyloxy snane and the basic compound are preferably mixed together prior to the addition of water and subsequently dissolved in water.
  • Exemplary basic compounds include the carbonates, hydrogen carbonates and hydroxides of the alkali and alkaline earth metals, organic amines, ammonia, amides and the like A mixture of different basic compounds may be added to the treatment composition
  • the basic compound is a basic silane compound.
  • ammo silanes are particularly preferred.
  • ammo silanes which may be employed in the present invention each have a single tnsubstituted silyl group in addition to the basic amine moiety, wherein at least on of the substituents is an alkoxy group.
  • the ammo silanes which maybe used m the present invention have the general structure
  • R 2 is chosen from the group consisting of hydrogen and C 1 -C 24 alkyl, preferably C.-C 6 alkyl and each R 2 may be the same or different.
  • R 2 is individually chosen from the group consisting of hydrogen, ethyl, methyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl and ter-butyl.
  • X 1 is a group selected from the group consisting of a bond, a substituted or unsubstituted aliphatic or aromatic group.
  • X 1 is selected from the group consisting of a bond, C C 6 alkylene, C 2 -C ⁇ alkenyiene, alkylene substituted with at least one amino group, C 2 -C 6 alkenyiene substituted with at least one ammo group, C 6 - 18 arylene and C 7 -C 1 ⁇ alkylaryle ⁇ e;
  • R 3 ⁇ s a group individually selected from the group consisting of hydrogen, C,-C 6 alkyl, C 2 -C 6 alkenyl, C.-C 6 alkyl substituted with at least one amino group, C 2 -C 6 alkenyl substituted with at least one am o group, arylene and alkylarylene.
  • R 3 is individually selected from the group consisting of hydrogen, ethyl, methyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl ter-DUtyl and acetyl.
  • ammo silanes employed in the method of the present invention are ⁇ -ammopro ⁇ yltr ⁇ ethoxysilane and ⁇ -aminopro ⁇ yl trimethoxysdane.
  • the amino silane may be a bis-silyl ammos ⁇ lane(s)
  • Such a compound comprises an aminosilane having two tnsubstituted silyl groups, wherein the substituents are individually selected from the group consisting of hydroxy and alkoxy
  • the bis-silyl aminosilane comprises
  • each R" is individually selected from the group consisting of: hydrogen and C, - C 2 climate alkyl; each R 5 is individually selected from the group consisting of: substituted aliphatic groups, unsubstituted aliphatic groups, substituted aromatic groups, and unsubstituted aromatic groups; and X 2 is either.
  • each R ⁇ is individually selected from the group consisting of: hydrogen, substituted and unsubstituted aliphatic groups, and substituted and unsubstituted aromatic groups
  • R 7 is selected from the group consisting of: substituted and unsubstituted aliphatic groups, and substituted and unsubstituted aromatic groups
  • Particularly preferred bis-silyl ammosilanes which may be used in the present invention include:
  • acyloxy silanes and basic compounds are- vinylt ⁇ acetoxysilane and b ⁇ s-(trimethoxysilylpro ⁇ yl)amine;
  • additional basic compounds may be used, for example, the inorganic bases referred to above
  • the solutions and methods of the present invention may be used on a variety of metals, including steel, aluminium, aluminium alloys, zinc, zinc alloys, magnesium, magnesium alloys, copper, copper alloys, tin and tin alloys.
  • the present method is particularly useful on zinc, zinc alloy, and metals having a zinc-containmg coating thereon, as well as aluminium or aluminium containing substrates.
  • the treatment solutions and methods of the present invention are useful in preventing corrosion of steel having a zmc-contaming coating, such as- galvanized steel (especially not dipped galvanized steel), GALVALUME® (a 55%-A
  • a zmc-contaming coating such as- galvanized steel (especially not dipped galvanized steel), GALVALUME® (a 55%-A
  • Zinc and zinc alloys are also pa ⁇ icularly amenable to application of the treatment solutions and methods of the present invention
  • Exemplary zinc and zinc alloy materials include: titanium- zi ⁇ c (zinc which has a very small amount of titanium added thereto), zinc-nickel alloy (typically about 5% to about 13% nickel content), and zinc-cobalt alloy (typically about 1 % cobalt).
  • the solutions of the present invention may be applied to the metal prior to shipment to the end-user, and provide corrosion protection during shipment and storage (including the prevention of wet-storage stam such as white rust)
  • a paint or other polymer coating is desired, the end user may merely apply the paint or polymer (e g , such as adhesives, plastics, or rubber coatings) directly on top of the silane coating provided by the present invention
  • the silane coatings of the present invention not only provide excellent corrosion protection even without paint, but also provide superior adhesion of paint, rubber or other polymer layers
  • the silane coatings of the present invention need not be removed prior to painting (or applying other types of polymer coatings such as rubber)
  • Suitable polymer coatings include various types of paints, adhesives (such as epoxy automotive adhesives), and peroxide-cured rubbers (e.g., peroxide-cured natural, NBR, SBR, nit ⁇ le or silicone rubbers).
  • Suitable paints include polyesters, polyurethanes and epoxy-based paints.
  • Plastic coatings are also suitable including acrylic, polyester, polyurethane, polyethylene, polyimide, polyphenylene oxide, polycarbonate, polyamide, epoxy, phenolic, acrylonitnle- butadiene-styrene, and acetal plastics.
  • the coatings of the present invention prevent corrosion, they may also be employed as primers and/or adhesive coatings for other polymer layers.
  • Tne solutions of the present invention do not require the use or addition of silicates
  • compositions may optionally comprise other silane compounds to the acyloxy silanes or the basic silanes disclosed herein.
  • the treatment solution is aqueous, and may optionally include one or more compatible solvents (such as ethanol, methanol, propanol or isopropanol) although their presence is not normally required. Where an organic solvent is required, ethanol is preferred.
  • solutions of the present invention are substantially free of organic solvents and VOCs.
  • the silane(s) in the solution of the present invention are at least partially, and preferably are substantially fully hydrolyzed in order to facilitate the bonding of the silanes to the metal surface and to each other.
  • the alkoxy groups in the case of the non-acyloxy silanes and the acyloxy in the case of the acyloxy silanes are replaced by hydroxyl groups
  • Hydrolysis of the silanes may be accomplished, for example, by merely mixing the silanes in water, and optionally including a solvent (such as an alcohol) in order to improve silane solubility and solution stability.
  • the pH may be maintained below about 8, more preferably between about 4 and about 6, and even more preferably between about 4 and about 5
  • the various silane concentrations discussed and claimed herein are all defined in terms of the ratio between the amount (by volume) of unhydrolyzed s ⁇ lane(s) employed to prepare the treatment solution (i e , prior to hydrolyzation), and the total volume of treatment solution components (i.e., acyloxy silanes, basic compound, water, and optional solvents.
  • the concentrations herein refer to the total amount of unhydrolyzed acyloxy silanes employed, since multiple acyloxy silanes may optionally be present.
  • the basic compounds concentrations herein are defined m the same manner.
  • the concentration of hydrolyzed silanes in the treatment solution beneficial results will be obtained over a wide range of silane concentrations and ratios It is preferred, however, that the solution have at least about 0.1 % acyloxy silanes by volume, more preferably at least about 1 % acyloxy silanes by volume, most preferably between about 2% and about 5% by volume.
  • Lower vinyl silane concentrations generally provide less corrosion protection. Higher concentrations of acyloxy silanes (greater than about 10%) should also be avoided for economic reasons, and to avoid silane condensation (which may limit storage stability).
  • the concentration of the basic compound required m the treatment solution varies strongly with the type of acyloxy silane employed and the type of basic compound. Obviously, a strongly acidic solution produced by a highly acyloxy group-substituted acyloxy silane will require an appropriate amount of basic compound to result in a treatment solution with a pH in the pre-determined range. Once the pH of the acyloxy silane in solution is known, an appropriate amount of a basic compound (with a known pH value in solution) can be added to the solution. The relative acidity and basicity of the acyloxy silane and the basic compound may be established before the solution is made up and are commonly presented in standard tables reciting physical properties of known compounds.
  • the concentration of the basic compound is generally in the range of about 0.1 % and about 10% by volume.
  • the solution should have at least about 0 1 % basic silanes by volume, more preferably at least about 1 % basic silane by volume, more preferably between about 2% and about 10%, most preferably between about 2% and about 5% by volume
  • the ratio of acyloxy si lanes to basic compound a wide range of ratios may be employed, and the present invention is not limited to any particular range of silane ratios.
  • the mixture of the acyloxy and basic compound may be provided to the user in a pre-mixed, unhydrolysed form which improves shelf life as con ⁇ ensation of the siiane is restrictive ⁇ . Sucn a mixture can then be made up into a treatment solution as defined herein.
  • a pre-mixed, unhydrolysed compositions should preferably be substantially free of water but may include one or more organic solvents (such as alcohols).
  • the composition may also include other components such as stabilizers, pigments, desicca ⁇ ts, and the like
  • Such a pre-mixed composition can be made up with a pre-determined amount of acyloxy silane and basic compound so that the addition of the mixture to water results in a pH within the preferred range.
  • composition can be presented in a "two-pack" kit, wnerem one part of the kit comprises the acyloxy silane, while another part of the kit provides the basic compound
  • the acyloxy silane and basic compound, along with the other components of the composition are provided in a concentrated form as a powder or liquid mixture.
  • the concentrate is substantially free of water and may be presented in a hermetically sealed container or kit.
  • substantially no organic solvent is present the composition.
  • the concentration of the acyloxy silane and basic compound in the pre- mixed concentrate composition is generally in the range 10-100%, preferably 15-
  • the concentrate may contain numerous additional components such as stabilisers, pigments, anti-oxidants, basic pH adjusters, desiccants, adhesion promoters, corrosion inhibitors and the like
  • the treatment method itself is very simple Where the solution is to be made up of separately presented components, the unhydrolyzed acyloxy silane, water, basic compound, solvent (if desired), are combined with one another.
  • the solution is then stirred at room temperature in order to hydrolyze the silanes.
  • the solution generally goes clear when hydrolysis is complete
  • tne composition is simply added to a pre-determined amount of water and mixed until the solution is substantially clear
  • the metal surface to be coated with the solution of the present invention may be solvent and/or alkaline cleaned by techniques well-known to those skilled in the art prior to application of the treatment solution of the present invention
  • the silane solution is then applied to the metal surface (i.e., the sheet is coated with the silane solution) by, for example, dipping the metal into the solution (also referred to as "rinsing"), spraying the solution onto the surface of the metal, or even brushing or wiping the solution onto the metal surface
  • dipping the metal into the solution also referred to as "rinsing”
  • spraying the solution onto the surface of the metal or even brushing or wiping the solution onto the metal surface
  • the duration of dipping is not critical, as it generally does not significantly affect the resulting film thickness. It is merely preferred that whatever application method is used, the contact time should be sufficient to ensure complete coating of the metal For most methods of application, a contact time of at least about
  • acyloxy silane concentration is reduced and the acetic acid concentration remains approximately constant as long as no further acyloxy silane is added to the solution
  • acetic acio is built up m the solution.
  • pH adjusters may be added such as basic compounds as hereinbefore described, buffers and the like.
  • a basic compound may be added along with the additional acyloxy silane which forms a sail with the acid in solution This may form an insoluble salt which can be removed from the process.
  • the treatment solution may also be heated when applying the treatment solution.
  • the temperature of the treatment solution is generally in the range 20°C to 80°C, preferably 30°C to 50°C
  • the metal sheet may be air-d ed at room temperature, or, more preferably, placed into an oven for heat drying.
  • Preferable heated drying conditions include temperatures between about 20°C and about 200 °C with drying times of between about 30 seconds and about 60 minutes (higher temperatures allow for shorter drying times) More preferably, heated drying is performed at a temperature of at least about 90°C, for a time sufficient to allow the silane coating to dry. While heated drying is not necessary to achieve satisfactory results, it will reduce the drying time thereby lessening the likelihood of the formation of white rust during drying.
  • the treated metal may be shipped to an end-user, or stored for later use.
  • A1170 ⁇ /TAS treated panels showed almost original surface after 7 days of exposure to SST, i.e , only slight edge corrosion occurred during testing 4.
  • the blank panels corroded heavily, while the chromated ones pitted slightly.
  • A1170/VTAS water-based silane film was applied on A12023-T3 and HDG, respectively.
  • the treated panels were then powder-painted at Lakebluff with Polyester and Polyurethane powder paints. After that, the panels were put mto salt spray chamber for some times, along with the control panels, the blank and the chromated Three replicates were made for each treatment The results are shown in Fig. 3 1.
  • A12024-T3 painted with both powder paints l OOOhrs in

Abstract

Cette invention a trait à une méthode de traitement d'une surface métallique, consistant à appliquer sur cette surface une solution contenant au moins un acyloxy-silane et au moins un composé basique. Elle concerne également une composition comprenant au moins un acyloxy-silane et au moins un composé basique. Elle porte également sur une surface métallique revêtue de silane.
PCT/US2000/019646 1999-07-19 2000-07-19 Traitement de métaux à l'acyloxy-silane WO2001006036A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
AT00948777T ATE310108T1 (de) 1999-07-19 2000-07-19 Metallbehandlung mittels acyloxy silane
EP00948777A EP1198616B1 (fr) 1999-07-19 2000-07-19 Traitement de m taux l'acyloxy-silane
AU62225/00A AU766638B2 (en) 1999-07-19 2000-07-19 Acyloxy silane treatments for metals
CA002378851A CA2378851A1 (fr) 1999-07-19 2000-07-19 Traitement de metaux a l'acyloxy-silane
US10/031,731 US6955728B1 (en) 1999-07-19 2000-07-19 Acyloxy silane treatments for metals
DE60024094T DE60024094T2 (de) 1999-07-19 2000-07-19 Metallbehandlung mittels acyloxysilan

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US09/356,926 US6827981B2 (en) 1999-07-19 1999-07-19 Silane coatings for metal
US09/356,926 1999-07-19
EPPCT/EP00/06794 2000-07-17
EP00006794 2000-07-17

Publications (1)

Publication Number Publication Date
WO2001006036A1 true WO2001006036A1 (fr) 2001-01-25

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Application Number Title Priority Date Filing Date
PCT/US2000/019646 WO2001006036A1 (fr) 1999-07-19 2000-07-19 Traitement de métaux à l'acyloxy-silane

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WO (1) WO2001006036A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6755918B2 (en) 2002-06-13 2004-06-29 Ming-Der Ger Method for treating magnesium alloy by chemical conversion
US6777094B2 (en) * 2001-06-28 2004-08-17 Alonim Holding Agricultural Cooperative Society Ltd. Treatment for improved magnesium surface corrosion-resistance
US8153705B2 (en) * 2003-05-07 2012-04-10 Sigmakalon B.V. Silyl esters, their use in binder systems and paint compositions and a process for production thereof
US8609755B2 (en) 2005-04-07 2013-12-17 Momentive Perfomance Materials Inc. Storage stable composition of partial and/or complete condensate of hydrolyzable organofunctional silane

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5750197A (en) * 1997-01-09 1998-05-12 The University Of Cincinnati Method of preventing corrosion of metals using silanes
WO1998019798A2 (fr) * 1996-11-05 1998-05-14 The University Of Cincinnati Procede anticorrosion pour feuille metallique utilisant des silanes de vinyle
WO1999020705A1 (fr) * 1997-10-23 1999-04-29 Aar Cornelis P J V D Collage caoutchouc sur metal par des agents de couplage renfermant un silane

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998019798A2 (fr) * 1996-11-05 1998-05-14 The University Of Cincinnati Procede anticorrosion pour feuille metallique utilisant des silanes de vinyle
US5750197A (en) * 1997-01-09 1998-05-12 The University Of Cincinnati Method of preventing corrosion of metals using silanes
WO1999020705A1 (fr) * 1997-10-23 1999-04-29 Aar Cornelis P J V D Collage caoutchouc sur metal par des agents de couplage renfermant un silane

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6777094B2 (en) * 2001-06-28 2004-08-17 Alonim Holding Agricultural Cooperative Society Ltd. Treatment for improved magnesium surface corrosion-resistance
US6755918B2 (en) 2002-06-13 2004-06-29 Ming-Der Ger Method for treating magnesium alloy by chemical conversion
US8153705B2 (en) * 2003-05-07 2012-04-10 Sigmakalon B.V. Silyl esters, their use in binder systems and paint compositions and a process for production thereof
US8609755B2 (en) 2005-04-07 2013-12-17 Momentive Perfomance Materials Inc. Storage stable composition of partial and/or complete condensate of hydrolyzable organofunctional silane
US10041176B2 (en) 2005-04-07 2018-08-07 Momentive Performance Materials Inc. No-rinse pretreatment methods and compositions

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