CA2095810A1 - Coating composition and process - Google Patents
Coating composition and processInfo
- Publication number
- CA2095810A1 CA2095810A1 CA 2095810 CA2095810A CA2095810A1 CA 2095810 A1 CA2095810 A1 CA 2095810A1 CA 2095810 CA2095810 CA 2095810 CA 2095810 A CA2095810 A CA 2095810A CA 2095810 A1 CA2095810 A1 CA 2095810A1
- Authority
- CA
- Canada
- Prior art keywords
- carbon atoms
- composition
- aluminium
- carboxylic acid
- zirconium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
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
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/08—Anti-corrosive paints
- C09D5/082—Anti-corrosive paints characterised by the anti-corrosive pigment
-
- 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
Abstract
An aqueous composition, comprising an aluminozirconate complex and a film-forming polymer, is useful in reducing long term deterioration of metal surfaces, particularly the exposed surfaces of zinc galvanised steel panels or sheets.
Description
~ W092t08822 2 0 9 5 810 PCT/GB91/01958 ....s Coating composition and process This invention concerns a composition for coating metal surfaces and to a process for coating metal surfaces.
;In the manufacture of zinc-, zinc alloy-, aluminium- or other metal-coated metal articles or sheetf or articles or sheet of aluminium, aluminium alloys, copper, copp~r alloys~ ' steel or of other metals or alloys, it is desirable to apply one or more protective coatings to the surface with a view to alleviating the problems of'deterioration of the surface in storage and/or of the provision of an effective base for later painting, varnishing, priming, enamelling or like operations. It is to these problems that the invention particularly relates.
.
A zinc-coated steel surface, for example, has a ~endency/ if untreated, to develop a white coloured powdery deposit in storage, so-called "white rust', which detracts from the appear~nce of the surface and possibly adversely affects the key of paint and the like onto the surface.
European Patont Specification No. 356855 relates to the problem outlined above. That specification refexs to the established usage of chromium compounds to achieve the inhibition of corrosion of aluminium and zinc, and cites the considerable pxoblems of effluent monitoring and di~posal and the need to take precautions to en~ure the protection of plant operatives which arises from the extremely toxic nature of the chromium compounds. The specification teaches that certain aluminium-zirconium complexes may be used in place of the chromium compounds.
The approach disclosed in European Patent Specification No. 356855 derived from the earlier teachings in United States Patent No. 4650526 which utilised similar aluminium-zirconium complexes to treat metal surfaces which had "' ' .' :' ' ' , ,. . " " ", '',' ' ;, .'' . ~ ' .' ,, ' ' , W092/08822 ~ PCT/G~9~0~9S8 already been subjected to a phosphating treatment to improve corrosion resistance, a purpose of the aluminium-zirconium treatment being to improve the adhesion of later siccative organic coatings to the phosphate-treated surface. ~he United States patent teaches the use of aqueous solutions containing 0.OOS to 5% by volume of the commercial aluminium-zirconium complex product. In many instances the performance of the phosphated, aluminium-zirconium complex~
treated metal surfaces were found to be inferior to that of chromated metal surfaces in respect of corrosion prevention and adhesion of alkyd paint films.
In order to improve the performance of aluminium-zirconium complex-treated metal surfaces European Patent Specification No. 356855 teaches the coating of the complex~
treated surface, after rinsing and drying, with an aqueous solution, emulsion or dispersion of a film-forming agent, such as polyacrylic acid. The aluminium-zirconium complex is used at concentrations of 0.1% or 1.0~ by volume of the commercial fonmp which contains 20-24% wt of the complex, and the organic ~ilm~
forming composition in 0.5 to 1 g/l. It has been found, however~
that the process described in the European patent specificati.on may not provide adequate, long-term resistance to surface deterioration since the zircoaluminate coating tends to shrink on drying, before the film-forming agent is applied, leaving regions of the metal surface effectively untreated with complex.
According to the present invention it has been found that excellent corrosion prevention and adhesion properties may be obtained on the aforesaid metals, for example on phosphated or non-phosphated surfaces of zinc-, zinc alloy-or aluminium-coated metals, using a one-coat non-rinse `
process, by the use of a treating composition characterised in that the composition comprises an aqueous solution, emulsion or dispersion of an organic film-forming polymer and one or more aluminium-zirconium complexes. Galvanised steel panels coated with the compositions of the present invention demonstrate a long .: ' ' : ' ' :': . .: ., ` ". .,, , :: ~ ' ' :'~: ~ . ` : ' ' ' ~ ': ` ., ` .
'; ' ' ,` ' ': , ' .
~ W092/08822 2 0 9 ~ ~ I O PCT/GB91/01958 term resistance to surface deterioration c~mmensurate with known chromium-based coatings. Further, the compositions of the present invention tend not to suffer the 'shrinkage problems associated with known aluminozirconate coatings.
Aluminium-zirconium complexes which may be utilised according to the invèntion are, for example, the reaction product of a chelated aluminium moiety, a zirconium oxyhalide and an organofuctional ligand. The organofunctional ligand is complexed with and chemically bound to the chelated aluminium moiety and the zirconium moiety.
The chelate-stabilised aluminium moiety has the general formula- -A12(O~lo)aAbBc (I) wherein A and B are halo-, preferably chloro-, or hydroxy-, ~a" is a numerical value of from 0.05 to 2, preferably from 0~1 to 1, "b" is a numerical value of from 0.05 to 5.5, preferably from 1 to 5, "c" is a numerical value of from 0.05 to 5.5, preferably from 1 to 5, provided that 2a + b + c = 6, and -OR10- is either an alpha-beta or alpha-gamma glycol group in which Rl is an alkyl, alkenyl, or alkynyl group having from 1 to 6 carbon atoms, preferably an alkyl group and preferably having 2 or 3 carbon atoms; or an alpha-hydroxy carboxylic acid residue of the formula -oCH(R3)-CooH, where R3 is H- or an-alkyl- group ha~ing from 1 to 4 carbon atoms, preferably from`2 to 3 carbon atoms.
~he zirconium oxyhalide, preferably an oxychloride, has the general formula:
ZrAdBe (II) wherein ~ ' ~
;In the manufacture of zinc-, zinc alloy-, aluminium- or other metal-coated metal articles or sheetf or articles or sheet of aluminium, aluminium alloys, copper, copp~r alloys~ ' steel or of other metals or alloys, it is desirable to apply one or more protective coatings to the surface with a view to alleviating the problems of'deterioration of the surface in storage and/or of the provision of an effective base for later painting, varnishing, priming, enamelling or like operations. It is to these problems that the invention particularly relates.
.
A zinc-coated steel surface, for example, has a ~endency/ if untreated, to develop a white coloured powdery deposit in storage, so-called "white rust', which detracts from the appear~nce of the surface and possibly adversely affects the key of paint and the like onto the surface.
European Patont Specification No. 356855 relates to the problem outlined above. That specification refexs to the established usage of chromium compounds to achieve the inhibition of corrosion of aluminium and zinc, and cites the considerable pxoblems of effluent monitoring and di~posal and the need to take precautions to en~ure the protection of plant operatives which arises from the extremely toxic nature of the chromium compounds. The specification teaches that certain aluminium-zirconium complexes may be used in place of the chromium compounds.
The approach disclosed in European Patent Specification No. 356855 derived from the earlier teachings in United States Patent No. 4650526 which utilised similar aluminium-zirconium complexes to treat metal surfaces which had "' ' .' :' ' ' , ,. . " " ", '',' ' ;, .'' . ~ ' .' ,, ' ' , W092/08822 ~ PCT/G~9~0~9S8 already been subjected to a phosphating treatment to improve corrosion resistance, a purpose of the aluminium-zirconium treatment being to improve the adhesion of later siccative organic coatings to the phosphate-treated surface. ~he United States patent teaches the use of aqueous solutions containing 0.OOS to 5% by volume of the commercial aluminium-zirconium complex product. In many instances the performance of the phosphated, aluminium-zirconium complex~
treated metal surfaces were found to be inferior to that of chromated metal surfaces in respect of corrosion prevention and adhesion of alkyd paint films.
In order to improve the performance of aluminium-zirconium complex-treated metal surfaces European Patent Specification No. 356855 teaches the coating of the complex~
treated surface, after rinsing and drying, with an aqueous solution, emulsion or dispersion of a film-forming agent, such as polyacrylic acid. The aluminium-zirconium complex is used at concentrations of 0.1% or 1.0~ by volume of the commercial fonmp which contains 20-24% wt of the complex, and the organic ~ilm~
forming composition in 0.5 to 1 g/l. It has been found, however~
that the process described in the European patent specificati.on may not provide adequate, long-term resistance to surface deterioration since the zircoaluminate coating tends to shrink on drying, before the film-forming agent is applied, leaving regions of the metal surface effectively untreated with complex.
According to the present invention it has been found that excellent corrosion prevention and adhesion properties may be obtained on the aforesaid metals, for example on phosphated or non-phosphated surfaces of zinc-, zinc alloy-or aluminium-coated metals, using a one-coat non-rinse `
process, by the use of a treating composition characterised in that the composition comprises an aqueous solution, emulsion or dispersion of an organic film-forming polymer and one or more aluminium-zirconium complexes. Galvanised steel panels coated with the compositions of the present invention demonstrate a long .: ' ' : ' ' :': . .: ., ` ". .,, , :: ~ ' ' :'~: ~ . ` : ' ' ' ~ ': ` ., ` .
'; ' ' ,` ' ': , ' .
~ W092/08822 2 0 9 ~ ~ I O PCT/GB91/01958 term resistance to surface deterioration c~mmensurate with known chromium-based coatings. Further, the compositions of the present invention tend not to suffer the 'shrinkage problems associated with known aluminozirconate coatings.
Aluminium-zirconium complexes which may be utilised according to the invèntion are, for example, the reaction product of a chelated aluminium moiety, a zirconium oxyhalide and an organofuctional ligand. The organofunctional ligand is complexed with and chemically bound to the chelated aluminium moiety and the zirconium moiety.
The chelate-stabilised aluminium moiety has the general formula- -A12(O~lo)aAbBc (I) wherein A and B are halo-, preferably chloro-, or hydroxy-, ~a" is a numerical value of from 0.05 to 2, preferably from 0~1 to 1, "b" is a numerical value of from 0.05 to 5.5, preferably from 1 to 5, "c" is a numerical value of from 0.05 to 5.5, preferably from 1 to 5, provided that 2a + b + c = 6, and -OR10- is either an alpha-beta or alpha-gamma glycol group in which Rl is an alkyl, alkenyl, or alkynyl group having from 1 to 6 carbon atoms, preferably an alkyl group and preferably having 2 or 3 carbon atoms; or an alpha-hydroxy carboxylic acid residue of the formula -oCH(R3)-CooH, where R3 is H- or an-alkyl- group ha~ing from 1 to 4 carbon atoms, preferably from`2 to 3 carbon atoms.
~he zirconium oxyhalide, preferably an oxychloride, has the general formula:
ZrAdBe (II) wherein ~ ' ~
2 ~ 9 ~ 81 0 PCI`/GB91/07958 :~ --4 -:: A and s are as defined for ( I ) above, preferably one of A and B
is chloro- and the other of A and B is hydroxy-, and "d" and "e" independantly have numerical values of from OOOS to ~: 4, provided that d + e = 4.
.
The organofunctional ligand (LIG) is derived from one'or more of :~ the following:
-1) an alkyl-, alkenyl-, alkynyl-, aryl- or aralkyl-carboxylic acid having from 2 to 36 carbon atoms, preferably from 2 to 18 carbon atoms, more preferably from 4 to 18 carbon atoms and even more preferably from 2 to 6 carbon atoms;
2) an aminofunctional carboxylic acid having from 2 to 36 carbon atoms, preferably from 2 to 18 carbon atoms, more preferably from 4 to 18 carbon atoms and moxe preferably from 2 to 6 carbon atoms;
is chloro- and the other of A and B is hydroxy-, and "d" and "e" independantly have numerical values of from OOOS to ~: 4, provided that d + e = 4.
.
The organofunctional ligand (LIG) is derived from one'or more of :~ the following:
-1) an alkyl-, alkenyl-, alkynyl-, aryl- or aralkyl-carboxylic acid having from 2 to 36 carbon atoms, preferably from 2 to 18 carbon atoms, more preferably from 4 to 18 carbon atoms and even more preferably from 2 to 6 carbon atoms;
2) an aminofunctional carboxylic acid having from 2 to 36 carbon atoms, preferably from 2 to 18 carbon atoms, more preferably from 4 to 18 carbon atoms and moxe preferably from 2 to 6 carbon atoms;
3) a,dibasic carboxylic acid having from 2 to 18 carbon atoms, preferably from 2 to 6 carbon atoms, and wherein both carboxy groups are preferably terminal;
- 4),,acid,anhydrides of,dibasic acids having from 2 to 18 carbon atoms, preferably from 2 to 6 carbon atoms;
5) a mercapto functional carboxylic acid having from 2 to 18 carbon atoms, preferably 2 to 6 carbon atoms; and 6) an epoxy functional carboxylic acid having from 2 to 18 carbon atoms, preferably from 2 to 6 caxbon atoms.
The aluminium~zirconium complex may be empirically represented by the general formula:
[A12(0Rlo)aAbBc~x[LIG]y~2rAdBc]z wherein A and B are as abo~e-defined, and a,b,c,d and e are as defined abo~e, except that, in order to form the bonds depicted, the substituents attached to the metal groups are appropriately reduced, i.e. 2a + h + c = 4 (2a + b + c = 5 when the aluminium moiety is a terminal group), and d + e =
2~9.581~
WO 92/08822 PC~/GB91/019S8 '` ~ .
2 (d + e = 3 when the zirconium moiety is a terminal group).
When the aluminium moiety or the zirconium moiety terminates the above formula, one of the A or B groups may be replaced by a (Cl-C6)alkoxy- group. x, y and z are independantly at least 1 and may vary from 1 to 100 or more. The molar ratio of x to z may vary from 1.5 to 10 with the preferred ratio being from 3 to 6 and the ratio of (y/(2x + z)) may vary from 0.05 to 3, preferably from 0.05 to 2.0, and more preferably from 0.1 to 0.5O
Nethods for the preparation of the above described complexes are described in United States Patent Specifications No. 4539048 and 4539049, the disclosures of which are incorporated herein by reference.
Very suitably the aluminium-zirconium complexes utilised according to this invention may be those available under the Trade Name Manchem as about ~0% to 25% vol solutions in polar solvents such as the lower alcohols, glycols, or glycol ethers of which suitable products are~
for example,those desiynated APG-X, in which the carboxylic acid component is NH2-(CH2)2-COOH, or CPG or CPM, in which the carboxylic acid components are HOOC-(CH2)4-COOH.
.
The organic film-forming polymer may be any polymer which is available as and curable in an aqueous solution dispexsion or emulsion. Preferably, however, the film-forming polymer is selected from suitable vinyl polymers or copolymers, for example vinyl-acrylic copolymers, polyacrylic and polymethacrylic acids, and polyacrylates and polymethacrylates. The most preferred film-forming pol~mers are emulsions of acrylic coplymers such as those emulsions available under the Trade Name Neocryl (from ICI). Suitably such polymers may themselves contain corrosion inhibitors. A
suitable solids content for the organic film-forming polymer is from about 30% to 50%, or even up to 75~, by weight.
The aluminium-zirconium complex may be present in the composition of the present invention in an amount of from n . 2% to 20% by , :
"
., W092/08822 . 2 0 9 ~ ~1 0 PCT/GB91/019S~
weight based on the weight of the total aqueous composition although particularly successful results have been achieved us ng at least 5% by weight, for example 5 to 20% by weight, on the same basis. The film-forming polymer may be present in greater than 2%, for example from 2% to 20%, by weight of polymer solids on the same basis. A solution of the aluminium-zirconium compound in an organic polar water-miscible solvent may be mixed with the aqueous solution, dispersion, or emulsion of the film-forming polymer, preferably to give the above stated solids concentrations and the resulting product may therefore have a substantial content of said organic polar solvent.
Preferably, a substantial proportion of a silane, ~or example from 2 to 15% by weiyht of a commercial silane composition which may for example contain from 50% to 95~ active material, ba~ed on the weight of the total aqueous composition, is included in the composition of this invention to increase the adhesion of subsequent organic surface coatings to the treated metal surEaceO
Preferably the silane has alkoxy groups, pre~erably 2 or 3 such groups, hydrolysis of which will permit reaction with acti~e sites on the metal substrate, and 1 or more organic groups capable of giving compatability with the film-forming polymer and/or polymers present in subsequent surface coatings. Ex~mples of suitable silanes are 3-aminopropyl-triethoxysilane, N-aminoethyl-3-aminopropyl trimethoxysilane and vinyl triethoxysilane which may suitably be in the form of 50% to 95%
concentration products.
A small ~uantity of a defoamer and/or surfactant is also preferably included. A suitable quantity of each is about 0 5 01~
to 0.5% by weight of the total composition may be used. Suitable materials may be that available under the trade name Bevaloid 6575M, polyoxyethylene-polyoxypropylene block copolymers, fluorosurfactants or non-ionic hydrocarbon surfactants.
When prepared for use in a dip tank, each litre of a preferred composition of the present invention will typically comprise from 20 to 200g, preferably 30 to 150g, of aluminium-., .: . .. . . .
- ' ' ' , ' ' ' ' ' . ;' ' ' W092/08822 2 0 9 5 ~1 U pcr/cBs1/ol~5g zirconium complex and from 1 to lOOg (polymer solids), preferably from 30 to 95g, of film-forming polymer.
.
The composition according to the present invention may be applied to the metal surfaces to be treated for example to a metal coil after hot dip or electrogalvanising or aluminium coating and after the temperature of the metal has ~allen to below about 85C preferably to below 80C. The method of application may be by spray or by immersion wi~h surplus liquid being removed, suitably by passing the metal between rollers or by the use of an air-knife. The metal may then be air or oven dried, for example at from 65C to 85C.The thickness of the coating is preferably up to about 50 microns, for example l to 10 microns which may be controlled by adjusting the solids concentration of the treating composition appropriately.
The coatings attained by the use of the prese~t invention adhere strongly to the metal surface to which they are applied, help to retain the metal surface in bright, uncorroded form, and give a good key to subsequent surface coatings. Accordingly, the compositions of the present invention may suitably be used in or as coatings, such as prLmers or finishes.
These properties may be tested by the following tests.
a) Salt spray corrosion test (ASTM B.117) b) Humidity test (1) BS.3900:Part F2:1~73~1983).
-resistance to humidity-cyclic conden~ation.
(2) BS.3900:Part F9:1982(1985) -resiskance to humidity-continuous condensation.
c) Stack test ( Butler Building Test).
Stacking under artificially humid conditions provided by interleaved wetted filter paper for a number of days followed by a determination of the proportion of the area covered by white rust.
, .. . ..
, ., :, , , , .- ... . .
,: -: - ., , : . . :, ,., , :
WO 92/(181iZ2 ~ ? 5 819 PCI/GB91/(~)958 d) Adhesion test. BS.3900:Part E6:1974.
Cross cut test.
The invention will now be illustrated by refer~nce to the following Examples and the drawings in which:
FIG 1 is a photograph of a galvanised steel panel treated in accordance with ~he process of EP-A-0356855 and illustrates the problems of l~shrinkage" where the metal surface has dark and light regions indicating where the metal surface is coated with zircoaluminate composition or uncoated respectively.
Example I
Galvanised steel panels were treated with a composition according to the invention comprising water, 15~ by weight of Haloflex vinylidene chloride copolymer (ICI), 10% by weight of a commercial ~inyl triethoxysilane product, 5~ by weight of Nanchem APG-X zircoaluminate product and 0.5% by weight of Synperonic PE/L61 polyoxyethylene block copolymer (ICI). The composition was applied at 5%v/v concentxation at 20 C by roller application to give an even film with a thickness of 5+/-2 microns (10-Çm) after drying. The panels were (a) left unpainted or were coated with ~b) a polyester or (c) ~n alkyd paint.
The panels were tested with the following resulks:
Test Unpainted Painted Polyester Alkyd a)Salt 48 Hours 250 Hours 120 Hours spray >10%white pass pass rust b)(l) 162 Hours - -Humidity <10~ White . ": ' '~,, . .: ' : . '. ' '; ' ' ' '' ".",', ,. ' '. . ':, ' ':
, ' ' . ' '' ::: ' . ~ . ' ': ' ~ '' ' " ' ~ WO 92/08822 2 o 9 s 8 1 ~ Pcr/~Bgl/olg58 --q-- f St b)Sta~k 30 Days-pass b - -test ~10% White ` rust (galvanised `
tube.
I
c)Cross cut test - Class O Class 1 Acce~kable : :-:, : , : , ,: ,, - ,.. : , . ,, ,.:.: . : .
: . , :: , ~ :: . " .
. . , " . ~ . .
The aluminium~zirconium complex may be empirically represented by the general formula:
[A12(0Rlo)aAbBc~x[LIG]y~2rAdBc]z wherein A and B are as abo~e-defined, and a,b,c,d and e are as defined abo~e, except that, in order to form the bonds depicted, the substituents attached to the metal groups are appropriately reduced, i.e. 2a + h + c = 4 (2a + b + c = 5 when the aluminium moiety is a terminal group), and d + e =
2~9.581~
WO 92/08822 PC~/GB91/019S8 '` ~ .
2 (d + e = 3 when the zirconium moiety is a terminal group).
When the aluminium moiety or the zirconium moiety terminates the above formula, one of the A or B groups may be replaced by a (Cl-C6)alkoxy- group. x, y and z are independantly at least 1 and may vary from 1 to 100 or more. The molar ratio of x to z may vary from 1.5 to 10 with the preferred ratio being from 3 to 6 and the ratio of (y/(2x + z)) may vary from 0.05 to 3, preferably from 0.05 to 2.0, and more preferably from 0.1 to 0.5O
Nethods for the preparation of the above described complexes are described in United States Patent Specifications No. 4539048 and 4539049, the disclosures of which are incorporated herein by reference.
Very suitably the aluminium-zirconium complexes utilised according to this invention may be those available under the Trade Name Manchem as about ~0% to 25% vol solutions in polar solvents such as the lower alcohols, glycols, or glycol ethers of which suitable products are~
for example,those desiynated APG-X, in which the carboxylic acid component is NH2-(CH2)2-COOH, or CPG or CPM, in which the carboxylic acid components are HOOC-(CH2)4-COOH.
.
The organic film-forming polymer may be any polymer which is available as and curable in an aqueous solution dispexsion or emulsion. Preferably, however, the film-forming polymer is selected from suitable vinyl polymers or copolymers, for example vinyl-acrylic copolymers, polyacrylic and polymethacrylic acids, and polyacrylates and polymethacrylates. The most preferred film-forming pol~mers are emulsions of acrylic coplymers such as those emulsions available under the Trade Name Neocryl (from ICI). Suitably such polymers may themselves contain corrosion inhibitors. A
suitable solids content for the organic film-forming polymer is from about 30% to 50%, or even up to 75~, by weight.
The aluminium-zirconium complex may be present in the composition of the present invention in an amount of from n . 2% to 20% by , :
"
., W092/08822 . 2 0 9 ~ ~1 0 PCT/GB91/019S~
weight based on the weight of the total aqueous composition although particularly successful results have been achieved us ng at least 5% by weight, for example 5 to 20% by weight, on the same basis. The film-forming polymer may be present in greater than 2%, for example from 2% to 20%, by weight of polymer solids on the same basis. A solution of the aluminium-zirconium compound in an organic polar water-miscible solvent may be mixed with the aqueous solution, dispersion, or emulsion of the film-forming polymer, preferably to give the above stated solids concentrations and the resulting product may therefore have a substantial content of said organic polar solvent.
Preferably, a substantial proportion of a silane, ~or example from 2 to 15% by weiyht of a commercial silane composition which may for example contain from 50% to 95~ active material, ba~ed on the weight of the total aqueous composition, is included in the composition of this invention to increase the adhesion of subsequent organic surface coatings to the treated metal surEaceO
Preferably the silane has alkoxy groups, pre~erably 2 or 3 such groups, hydrolysis of which will permit reaction with acti~e sites on the metal substrate, and 1 or more organic groups capable of giving compatability with the film-forming polymer and/or polymers present in subsequent surface coatings. Ex~mples of suitable silanes are 3-aminopropyl-triethoxysilane, N-aminoethyl-3-aminopropyl trimethoxysilane and vinyl triethoxysilane which may suitably be in the form of 50% to 95%
concentration products.
A small ~uantity of a defoamer and/or surfactant is also preferably included. A suitable quantity of each is about 0 5 01~
to 0.5% by weight of the total composition may be used. Suitable materials may be that available under the trade name Bevaloid 6575M, polyoxyethylene-polyoxypropylene block copolymers, fluorosurfactants or non-ionic hydrocarbon surfactants.
When prepared for use in a dip tank, each litre of a preferred composition of the present invention will typically comprise from 20 to 200g, preferably 30 to 150g, of aluminium-., .: . .. . . .
- ' ' ' , ' ' ' ' ' . ;' ' ' W092/08822 2 0 9 5 ~1 U pcr/cBs1/ol~5g zirconium complex and from 1 to lOOg (polymer solids), preferably from 30 to 95g, of film-forming polymer.
.
The composition according to the present invention may be applied to the metal surfaces to be treated for example to a metal coil after hot dip or electrogalvanising or aluminium coating and after the temperature of the metal has ~allen to below about 85C preferably to below 80C. The method of application may be by spray or by immersion wi~h surplus liquid being removed, suitably by passing the metal between rollers or by the use of an air-knife. The metal may then be air or oven dried, for example at from 65C to 85C.The thickness of the coating is preferably up to about 50 microns, for example l to 10 microns which may be controlled by adjusting the solids concentration of the treating composition appropriately.
The coatings attained by the use of the prese~t invention adhere strongly to the metal surface to which they are applied, help to retain the metal surface in bright, uncorroded form, and give a good key to subsequent surface coatings. Accordingly, the compositions of the present invention may suitably be used in or as coatings, such as prLmers or finishes.
These properties may be tested by the following tests.
a) Salt spray corrosion test (ASTM B.117) b) Humidity test (1) BS.3900:Part F2:1~73~1983).
-resistance to humidity-cyclic conden~ation.
(2) BS.3900:Part F9:1982(1985) -resiskance to humidity-continuous condensation.
c) Stack test ( Butler Building Test).
Stacking under artificially humid conditions provided by interleaved wetted filter paper for a number of days followed by a determination of the proportion of the area covered by white rust.
, .. . ..
, ., :, , , , .- ... . .
,: -: - ., , : . . :, ,., , :
WO 92/(181iZ2 ~ ? 5 819 PCI/GB91/(~)958 d) Adhesion test. BS.3900:Part E6:1974.
Cross cut test.
The invention will now be illustrated by refer~nce to the following Examples and the drawings in which:
FIG 1 is a photograph of a galvanised steel panel treated in accordance with ~he process of EP-A-0356855 and illustrates the problems of l~shrinkage" where the metal surface has dark and light regions indicating where the metal surface is coated with zircoaluminate composition or uncoated respectively.
Example I
Galvanised steel panels were treated with a composition according to the invention comprising water, 15~ by weight of Haloflex vinylidene chloride copolymer (ICI), 10% by weight of a commercial ~inyl triethoxysilane product, 5~ by weight of Nanchem APG-X zircoaluminate product and 0.5% by weight of Synperonic PE/L61 polyoxyethylene block copolymer (ICI). The composition was applied at 5%v/v concentxation at 20 C by roller application to give an even film with a thickness of 5+/-2 microns (10-Çm) after drying. The panels were (a) left unpainted or were coated with ~b) a polyester or (c) ~n alkyd paint.
The panels were tested with the following resulks:
Test Unpainted Painted Polyester Alkyd a)Salt 48 Hours 250 Hours 120 Hours spray >10%white pass pass rust b)(l) 162 Hours - -Humidity <10~ White . ": ' '~,, . .: ' : . '. ' '; ' ' ' '' ".",', ,. ' '. . ':, ' ':
, ' ' . ' '' ::: ' . ~ . ' ': ' ~ '' ' " ' ~ WO 92/08822 2 o 9 s 8 1 ~ Pcr/~Bgl/olg58 --q-- f St b)Sta~k 30 Days-pass b - -test ~10% White ` rust (galvanised `
tube.
I
c)Cross cut test - Class O Class 1 Acce~kable : :-:, : , : , ,: ,, - ,.. : , . ,, ,.:.: . : .
: . , :: , ~ :: . " .
. . , " . ~ . .
Claims (11)
1. An aqueous composition for coating metal, eg zinc, copper, steel or aluminium, surfaces comprising:
1) an aluminium-zirconium complex which is the reaction product of a chelated aluminium moiety, a zirconium oxyhalide and an organofuctional ligand, the organofunctional ligand being complexed with and chemically bound to the chelated aluminium moiety and the zirconium moiety, the aluminium moiety having the general formula A12(OR10)aAbBc (I) wherein A and B are halo-, preferably chloro-, or hydroxy-, "a" is a numerical value of from 0.05 to 2, preferably from 0.1 to 1, "b" is a numerical value of from 0.05 to 5.5, preferably from 1 to 5, "c" is a numerical value of from 0.05 to 5.5, preferably from 1 to 5, provided that 2a + b + c = 6, and -OR10- is either an alpha-beta or alpha-gamma glycol group in which R1 is an alkyl, alkenyl, or alkynyl group having from 1 to 6 carbon atoms, preferably an alkyl group and preferably having 2 or 3 carbon atoms; or an alpha-hydroxy carboxylic acid residue of the formula -OCH(R3)-COOH, where R3 is H- or an alkyl- group having from 1 to 4 carbon atoms, preferably from 2 to 3 carbon atoms; the zirconium oxyhalide, preferably an oxychloride, having the general formula:
ZrAdBe (II) wherein A and B are as defined for (I) above, preferably one of A
and B is chloro- and the other of A and B is hydroxy-, and "d" and "e" independantly have numerical values of from 0.05 to 4, provided that d + e = 4; and the organofunctional ligand (LIG) being one or more of the following:
(1) an alkyl-, alkenyl-, alkynyl-, aryl- or aralkyl-carboxylic acid having from 2 to 36 carbon atoms, preferably from 2 to 18 carbon atoms, more preferably from 4 to 18 carbon atoms and even more preferably from 2 to 6 carbon atoms;
(2) an aminofunctional carboxylic acid having from 2 to 36 carbon atoms, preferably from 2 to 18 carbon atoms, more preferably from 4 to 18 carbon atoms and more preferably from 2 to 6 carbon atoms;
(3) a dibasic carboxylic acid having from 2 to 18 carbon atoms, preferably from 2 to 6 carbon atoms, and wherein both carboxy groups are preferably terminal;
(4) acid anhydrides of dibasic acids having from 2 to 18 carbon atoms, preferably from 2 to 6 carbon atoms;
(5) a mercapto functional carboxylic acid having from 2 to 18 carbon atoms, preferably 2 to 6 carbon atoms; and (6) an epoxy functional carboxylic acid having from 2 to carbon atoms, preferably from 2 to 6 carbon atoms;
2) a film-forming polymer; and optionally 3) a silane.
1) an aluminium-zirconium complex which is the reaction product of a chelated aluminium moiety, a zirconium oxyhalide and an organofuctional ligand, the organofunctional ligand being complexed with and chemically bound to the chelated aluminium moiety and the zirconium moiety, the aluminium moiety having the general formula A12(OR10)aAbBc (I) wherein A and B are halo-, preferably chloro-, or hydroxy-, "a" is a numerical value of from 0.05 to 2, preferably from 0.1 to 1, "b" is a numerical value of from 0.05 to 5.5, preferably from 1 to 5, "c" is a numerical value of from 0.05 to 5.5, preferably from 1 to 5, provided that 2a + b + c = 6, and -OR10- is either an alpha-beta or alpha-gamma glycol group in which R1 is an alkyl, alkenyl, or alkynyl group having from 1 to 6 carbon atoms, preferably an alkyl group and preferably having 2 or 3 carbon atoms; or an alpha-hydroxy carboxylic acid residue of the formula -OCH(R3)-COOH, where R3 is H- or an alkyl- group having from 1 to 4 carbon atoms, preferably from 2 to 3 carbon atoms; the zirconium oxyhalide, preferably an oxychloride, having the general formula:
ZrAdBe (II) wherein A and B are as defined for (I) above, preferably one of A
and B is chloro- and the other of A and B is hydroxy-, and "d" and "e" independantly have numerical values of from 0.05 to 4, provided that d + e = 4; and the organofunctional ligand (LIG) being one or more of the following:
(1) an alkyl-, alkenyl-, alkynyl-, aryl- or aralkyl-carboxylic acid having from 2 to 36 carbon atoms, preferably from 2 to 18 carbon atoms, more preferably from 4 to 18 carbon atoms and even more preferably from 2 to 6 carbon atoms;
(2) an aminofunctional carboxylic acid having from 2 to 36 carbon atoms, preferably from 2 to 18 carbon atoms, more preferably from 4 to 18 carbon atoms and more preferably from 2 to 6 carbon atoms;
(3) a dibasic carboxylic acid having from 2 to 18 carbon atoms, preferably from 2 to 6 carbon atoms, and wherein both carboxy groups are preferably terminal;
(4) acid anhydrides of dibasic acids having from 2 to 18 carbon atoms, preferably from 2 to 6 carbon atoms;
(5) a mercapto functional carboxylic acid having from 2 to 18 carbon atoms, preferably 2 to 6 carbon atoms; and (6) an epoxy functional carboxylic acid having from 2 to carbon atoms, preferably from 2 to 6 carbon atoms;
2) a film-forming polymer; and optionally 3) a silane.
2. A composition as claimed in Claim 1, wherein component 1) is present in the composition in an amount of from 0.2 to 20% by weight of the total composition.
3. A composition as claimed in any one of the preceding claims, wherein component 2) is present in an amount of from 2 to 20 % by weight polymer solids of the total composition.
4. A composition as claimed in any one of the preceding claims , wherein component 2) is selected from the group consisting of vinyl polymers or copolymers, (meth)acrylic polymers or copolymers, (meth)acrylate polymers or copolymers, and mixtures thereof.
5. Use of a composition as claimed in any one of claims 1 to 4 in or as a dip tank fluid for preventing corrosion of metal surfaces.
6. Use of a composition as claimed in any one of claims 1 to 4 in or as a metal primer.
7. A dip tank fluid, suitable for preventing corrosion of zinc galvanised steel, comprising an aqueous composition, each litre of composition comprising from 20 to 200g, preferably 30 to 150g, of an aluminium-zirconium complex as defined in claim 1, and from 1 to 100g (polymer solids), preferably from 30 to 95g, of a film-forming polymer.
8. A zinc galvanised steel article, e.g. panel, wire, tube, ox plate, coated with a composition as claimed in any one of claims 1 to 4.
9. An aluminium article, e.g. panel, wire, tube, or plate, coated with a composition as claimed in any one of claims 1 to 4.
10. A metal primer comprising a composition as claimed in any one of claims 1 to 4.
11. A composition, method of application of a composition or use of a composition subsantially as hereinbefore defined with reference to the examples.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB909024474A GB9024474D0 (en) | 1990-11-10 | 1990-11-10 | Coating composition and process |
| GB9024474.0 | 1990-11-10 | ||
| GB919120440A GB9120440D0 (en) | 1990-11-10 | 1991-09-25 | Coating composition and process |
| GB9120440.4 | 1991-09-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2095810A1 true CA2095810A1 (en) | 1992-05-11 |
Family
ID=26297931
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2095810 Abandoned CA2095810A1 (en) | 1990-11-10 | 1991-11-07 | Coating composition and process |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0556250A1 (en) |
| AU (1) | AU8871391A (en) |
| CA (1) | CA2095810A1 (en) |
| WO (1) | WO1992008822A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9120442D0 (en) * | 1991-09-25 | 1991-11-06 | Laporte Industries Ltd | Coating composition and process |
| DE19516765A1 (en) * | 1995-05-06 | 1996-11-07 | Henkel Kgaa | Chromium and fluoride free treatment of metal surfaces |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4191596A (en) * | 1978-09-06 | 1980-03-04 | Union Carbide Corporation | Method and compositions for coating aluminum |
| US4650526A (en) * | 1986-03-18 | 1987-03-17 | Man-Gill Chemical Company | Post treatment of phosphated metal surfaces by aluminum zirconium metallo-organic complexes |
| US4978399A (en) * | 1988-01-04 | 1990-12-18 | Kao Corporation | Metal surface treatment with an aqueous solution |
| DE3829154A1 (en) * | 1988-08-27 | 1990-03-01 | Collardin Gmbh Gerhard | CHROME-FREE METHOD FOR PRE-TREATING METALLIC SURFACES BEFORE COATING WITH ORGANIC MATERIALS |
-
1991
- 1991-11-07 AU AU88713/91A patent/AU8871391A/en not_active Withdrawn
- 1991-11-07 EP EP19910919619 patent/EP0556250A1/en not_active Withdrawn
- 1991-11-07 WO PCT/GB1991/001958 patent/WO1992008822A1/en not_active Application Discontinuation
- 1991-11-07 CA CA 2095810 patent/CA2095810A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| WO1992008822A1 (en) | 1992-05-29 |
| AU8871391A (en) | 1992-06-11 |
| EP0556250A1 (en) | 1993-08-25 |
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