Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
  • C09C3/08—Treatment with low-molecular-weight non-polymer organic compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/28—Compounds of silicon
  • C09C1/30—Silicic acid
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/28—Compounds of silicon
  • C09C1/30—Silicic acid
  • C09C1/3063—Treatment with low-molecular organic compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/08—Anti-corrosive paints
  • C09D5/10—Anti-corrosive paints containing metal dust
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/12—Surface area
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/14—Pore volume
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/22—Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability

Definitions

• the present invention relates to dispersions of particles including anti- corrosive submicron particles.
• the present invention is also related to methods of making such dispersions and coatings made therefrom.
• cations and anions have corrosion inhibiting properties and that compounds containing them can be included in protective films and coatings that are intended to provide adhesion and corrosion inhibiting properties to metallic surfaces and structures.
• Typical examples include cations of calcium, magnesium, strontium, barium, manganese, zinc, cerium and other rare earth elements as well as anions such as silicate, borate, molybdate, nitrophthalate, phosphate, hydrogen phosphate, phosphite, phosphonates and phosphonocarboxylates.
• Classic inhibitors based on lead compounds and cations and compounds of some other heavy metals such as chromium e.g. chromate and zinc are however of less interest these days for environmental and health and safety reasons.
• the inhibitive compounds may be in the form of sparingly water- soluble salts and can for example be prepared by a process of particle growth and precipitation in the presence of the required cations and anions under suitable conditions.
• the inhibitive compounds may also be in the form of particles of inorganic oxides such as silica, silicates, alumina and aluminosilicates comprising additional inhibitive cations and anions. These inhibitive compounds can for example be prepared by a process of precipitation or gelation of the oxide in the presence of the required cations and anions under suitable conditions.
• Inhibitive compounds based on inorganic oxides can alternatively be made through a process of ion-exchange, in which surface protons and hydroxyl groups of the pre-formed oxide are replaced by contacting the oxide with a solution containing the required inhibitive cations and anions, again under suitable conditions.
• the inorganic oxides involved are often characterized by having certain surface areas and porosities with corrosion inhibiting ions attached to the internal and external surface of the particles, producing surface modified inorganic particles, although ions may be found through the bulk of the particles as well, depending on the method of preparation.
• the films and coatings employed in anti-corrosion have a certain permeability to water and it is believed that the mechanism of corrosion inhibition involves gradual dissolution of the compounds in water, releasing ions as the active inhibitors.
• the solubility of the compound is particularly important. If the compound is too soluble, blistering of the coating may occur and the compound will be rapidly depleted; if it is insufficiently soluble the compound will be ineffective.
• the inhibitive compound is a sparingly soluble salt, or based on an inorganic oxide or is some combination of the two, the typical solubility of such compounds suitable for use in films and coatings results in inhibitive ion concentrations in aqueous media of around 10 " M to 10 " M.
• the inorganic oxide may itself have a certain solubility with respect to the provision of inhibitive substances, according to the nature of the environment in which the corrosion inhibiting particles are used e.g. in the case of silica, silicic acid has a background solubility of about 10 "3 M with the concentration of silicate being pH dependent and having a value of 10 " M for example at a pH of about 10.5. It is however sometimes believed that these types of corrosion inhibiting particles can act to release inhibitive cations and anions into solution by ion exchange with aggressive ions existing in that environment as an additional or alternative mechanism of action to one based on dissolution.
• the rate of release of the corrosion inhibiting ions would then be influenced by the permeability of the film or coating to the exchanging ions in addition to or rather than dissolution of inhibitive ions into the permeating aqueous environment. Corrosion inhibiting ions would in that case be released to a greater extent from the inorganic oxide in those areas where the desired barrier properties of the coating were weakest, leading thereby to improved performance properties.
• the inhibitive compounds referred to above are usually made available in the form of dry powders, making use of washing, drying and milling operations as required as additional processing steps and average particle sizes of the powders usually exceed about 1 to 2 microns making them most suitable for films and coatings that exceed a few microns in thickness.
• the pH of an aqueous slurry of such inhibitive compounds will in most cases typically fall within the range of 4 to 10.5 although lower or higher values can be suitable depending on the actual chemistry of the coating or film in question and the nature of the metallic substrate. For example, many surface pre-treatments can be quite acidic and display a pH in the range of 1 to 4.
• anti-corrosive particles available in dispersion form would render the operation of incorporating the particles into the coating more convenient and would avoid generation of dust.
• known anti- corrosive particle dispersions contain pigment particles that are relatively large in size and greater than about 1 to 2 microns. Such dispersions are not suitable for use in filming and coating applications that require small particle sizes, such as chromium-free surface treatments or thin film primers where the film thickness may be less than a few microns going down to the sub-micron region. It is additionally believed that both the particle size and state of dispersion of the inhibitive pigment may influence the availability and mobility of inhibitive ions derived from the inhibitive compound within the film or coating under environmental exposure. Small particle pigments may therefore provide potential benefits in anti-corrosive treatment films and coatings regardless of the thickness of the film applied.
• the present invention relates to dispersion and dispersions of surface modified inorganic particles including (a) fluid, and (b) the surface modified inorganic particles comprising polyvalent metal ions and having an average particle diameter of about 10 microns or less.
• the present invention also relates to coating compositions including the above-mentioned dispersion.
• the present invention further relates to dispersion and dispersions of surface modified inorganic particles including (a) fluid comprising a complexing agent, and (b) the surface modified inorganic particles comprising polyvalent metal ions. Again coating compositions including these dispersions are also part of the present invention.
• a still further embodiment of the present invention comprises a method of making a dispersion of surface modified inorganic particles including (a) mixing said surface modified inorganic particles with a fluid; and (b) milling said inorganic particles to form particles having an average diameter of about 10 microns or less, wherein said inorganic oxide particles further comprise polyvalent metal ions.
• the present invention is concerned with corrosion inhibitors suitable for use in protective films, surface treatments, primers, coatings, adhesives and sealants that are intended to provide adhesion and corrosion inhibiting properties to metallic surfaces and structures. As described herein, all of these fields of application are encompassed by the single term "coating”.
• a corrosion inhibitor comprises particles of an inorganic oxide having corrosion inhibiting ions chemically bound to the particles.
• inorganic oxides means oxides of metals or metalloids. Metals include those elements on the left of the diagonal line drawn from boron to polonium on the periodic table. Metalloids or semi-metals include those elements that are on this line and include also silicon. Examples of inorganic oxides include silica, silicates, alumina, aluminosilicates, titania, zirconia, ceria and the like, or mixtures thereof.
• Inhibitive compounds based on inorganic oxides may, for example, be prepared by a process of precipitation or gelation of the oxide in the presence of the required cations and anions under suitable conditions.
• Inhibitive compounds based on inorganic oxides can alternatively be made through a process of ion- exchange, in which surface protons and hydroxyl groups of the pre-formed oxide are replaced by contacting the oxide with a solution containing the required inhibitive cations and anions, again under suitable conditions.
• the inorganic oxides involved are often characterized by having certain surface areas and porosities with corrosion inhibiting ions attached to the internal and/or external surface of the particles, producing surface modified inorganic particles, although ions may be found through the bulk of the particles as well, depending on the method of preparation.
• a corrosion inhibitor may also comprise combinations of inhibitive cations and anions in the form of sparingly soluble metal salts of the anion.
• Inhibitive compounds in the form of sparingly water-soluble salts can for example be prepared by a process of particle growth and precipitation from slurries or solutions in the presence of the required cations and anions under suitable conditions.
• Combinations of inhibitive compounds based on sparingly soluble salts and those based on inorganic oxides may be prepared by mixing the preformed substances, mixing pre-formed inorganic oxides or alternatively preformed inorganic oxides bearing inhibitive cations and anions with the appropriate inhibitive cations and anions as necessary such that particle growth and precipitation of sparingly soluble salts occurs in the presence of the inorganic oxide, where in all three cases, the inorganic oxide would exist in the presence of polyvalent cations.
• Combinations may also be made in which sparingly soluble inhibitive salts are combined with precursors to inorganic oxides like sodium silicate, alkyl silicates such as tetraethyl orthosilicate, aluminum chloride, aluminum hydroxychloride or sodium aluminate and so forth in the case of silica, alumina and aluminosilicates such that precipitation or gelation, or simply formation, of the inorganic oxide occurs, intimately associated with inhibitive cations and anions.
• mixtures of inhibitive cations and anions and precursors to inorganic oxides can be prepared such that particle growth, precipitation and/or gelation of sparingly soluble compounds and oxides occur simultaneously, intimately associated with one another.
• inhibitive combinations exist according to the composition of the solution or slurry from which the inhibitive compounds are to be prepared and the processing route, allowing for a great variety in properties displayed by the resulting inhibitive compound.
• Preferred cations are those of calcium (Ca 2+ ), magnesium (Mg 2+ ), zinc
• Zn 2+ manganese
• Mn 2+ manganese
• cations of the rare earth elements such as cerium (Ce 3+ /Ce 4+ ) cations, but other suitable cations may be cobalt (Co 2+ ), lead (Pb 2+ ), strontium (Sr 2+ ), lithium (Li + ), barium (Ba 2+ ) and aluminium (Al 3+ ).
• Preferred anions are those derived from silicate, borate, molybdate, hydrogen phosphate, phosphate, phosphite, nitrophthalates, phosphonate and phosphonocarboxylates as well as azoles and their derivatives such as 1,2,3-benzotriazole, tolytriazole, benzothiazole, 2-mercaptobenzothiazole, benzimidazole, 2-mercaptobenzimidazole and 2-mercaptobenzoxazole but other suitable anions may be permanganate, manganate, vanadate and tungstate.
• the free acid form or any other partially neutralized or fully neutralized form i.e., the conjugate species may be employed in any particular case as appropriate.
• the process of cation exchange with inorganic oxides can be considered.
• Particles of inorganic oxides such as silica, alumina and other oxides may be prepared such that a proportion of hydroxyl groups are present on the surface of the particles.
• the particles may differ in porosity from non- porous to highly porous, and may be in any shape from spherical to any non- spherical shape, and may be in the form of a gel, a precipitate, a sol (colloidal), fumed or other common form readily recognized in the art.
• Such oxide particles may be prepared according to the processes set forth in or referenced by U.S. Patents Nos.
• the protons of the hydroxyl groups may be replaced by contacting the oxide with a solution containing the required cations.
• a solution containing the required cations To carry out exchange the oxide may be stirred in water at room temperature and the pH monitored by a meter. Then the substance to be exchanged (e.g. calcium hydroxide or basic zinc carbonate) is added slowly whilst not allowing the pH to rise too far (e.g., above 10.5 for silica or 12 for alumina).
• the pH needs to be high enough to remove protons but not so high as to dissolve the inorganic oxide.
• the uptake can be followed by observing the fall of pH over a period of time following the addition of the base.
• the oxide particles may be milled, if necessary, washed and dried under vacuum. Uptake of cations in the oxide can be measured by XRF spectroscopy. Processes for making such exchanged oxides may be found in or referenced by U.S. Patents Nos. 4,687,595, 4,643,769, 4,419,137 and 5,041,241, the entire subject matter of which is incorporated herein by reference.
• the inorganic oxide inhibitor particles will have BET surface areas ranging from about 5m /g up to about 750 m 2 /g. with average porosities varying from about 0.1ml/g to about 3ml/g.
• the films and coatings employed in anti-corrosion have a limited permeability to water and the mechanism of corrosion inhibition is believed to involve gradual dissolution of the compounds in water with release of ions as the active inhibitors.
• the solubility of the compound is very important. If the compound is too soluble, blistering of the coating may occur and the compound will be rapidly depleted; if it is insufficiently soluble the compound will be ineffective.
• the inhibitive compound is purely a sparingly soluble salt, or based on an inorganic oxide or is some combination of the two, the typical water solubility of such compounds suitable for use in films and coatings results in inhibitive ion concentrations in aqueous media of around 10 " M to 10 ' M.
• the inorganic oxide may itself have a certain solubility with respect to the provision of inhibitive substances, according to the nature of the environment in which the corrosion inhibiting particles are used e.g. in the case of silica, silicic acid has a background solubility of about 10 "3 M with the concentration of silicate being pH dependent having a value of 10 " M for example at a pH of about 10.5.
• inhibitors based on inorganic oxides can act to release inhibitive cations and anions into solution by ion exchange with aggressive ions existing in the environment in which the inhibitive particles are used. It would then be permeability of the film or coating to the exchanging ions that would influence the rate of release of the corrosion inhibiting ions in addition to or rather than the mechanism involving solubilisation of inhibitive ions into the permeating aqueous environment. Corrosion inhibiting ions would in that case be preferentially released from the inorganic oxide in those areas where the desired barrier properties of the coating were weakest, leading thereby to improved performance properties.
• the pH of an aqueous slurry of inhibitive compounds will in most cases typically fall within the range of 4 to 10.5 although lower or higher values can be suitable depending on the actual chemistry of the coating or film in question and the nature of the metallic substrate.
• the pH of an aqueous slurry of inhibitive compounds will in most cases typically fall within the range of 4 to 10.5 although lower or higher values can be suitable depending on the actual chemistry of the coating or film in question and the nature of the metallic substrate.
• the corrosion inhibiting particles may act as filler for the coating and may be included in relatively large amounts of up to 40% wt, based on the composition to be applied and up to 80% wt based on the dry film weight.
• the coatings in that case may contain up to 2 millimoles/g of corrosion inhibiting cations based on the dry film weight.
• the polyvalent cations may arise from the pre-existing association of inhibitive cations with the inorganic oxide such as in the case of ion-exchanged oxides, or those produced by precipitation or co-gelation, or by addition of polyvalent cations during milling in the form of soluble or sparingly soluble compounds or they may be present according to any of the variety of ways by which combinations of inhibitive compounds can be prepared as discussed earlier.
• the polyvalent metal ions may cause significant aggregation of the small inorganic oxide particles or cause instability with respect to aggregation, agglomeration, high viscosities or settling when attempting to produce such small inorganic particles by milling.
• an embodiment of the present invention includes a dispersion of surface modified inorganic particles having fluid or liquid, the surface modified inorganic particles being modified by polyvalent metal ions and have an average particle diameter of about ten microns or less.
• the term "surface modified inorganic particle” relates to inorganic oxide particles in the presence of polyvalent cations, where the polyvalent cations may arise from processes such as are involved in preparing corrosion inhibitors based on inorganic oxides, from the presence of soluble and sparingly soluble compounds such as those involved in preparing corrosion inhibitors based on sparingly soluble salts and/or from other types of combinations of corrosion inhibiting species and compounds as previously detailed, under conditions such that uptake of the cations by the inorganic oxide can be expected.
• the average particle diameter may be less than about 10 microns, about 9 microns, about 8 microns, about 7 microns, 6 microns, about 5 microns, about 4 microns, about 3 microns, about 2 microns or less than about 1 micron. In a more typical embodiment, the average particle diameter is less than about 1 micron.
• the polyvalent metal ions may include calcium, zinc, cobalt, lead, strontium, lithium, barium, magnesium, manganese and cations of the rare earth elements such as cerium or mixtures thereof.
• the polyvalent metal ions include those of calcium, magnesium, manganese, zinc, and rare earth elements such as cerium.
• the particles may be corrosion inhibitors based on inorganic oxides, such as silicas and aluminas, milled separately or in combination with other inorganic oxides.
• Mixtures of different particle types are also included as are combinations of inhibitive compounds based on sparingly soluble salts and those based on inorganic oxides that may be prepared simultaneously in various ways according to the composition of the solution or slurry from which the inhibitive compounds are to be prepared and the processing route as described earlier.
• Another embodiment of the present invention relates to a dispersion of surface modified inorganic particles including (a) fluid comprising a stabilizing or complexing agent, and (b) the surface modified inorganic particles comprising polyvalent metal ions.
• the present invention also relates to coating compositions including the above-mentioned dispersion.
• the added substance used to stabilize the dispersion and/or complex the polyvalent cations may be a soluble or partially soluble component of the corrosion inhibiting compound, particle or mixture of particles.
• the added substances may be discrete compounds or may be oligomeric or polymeric in nature.
• the stabilizing and complexing agents may include various phosphorus and phosphorus free acidic substance as well as basic substances such as amines and alkanolamines.
• basic substances such as amines and alkanolamines.
• phosphorus containing acidic substances include phosphorus acid, phosphoric acid, tri- and polyphosphoric acids, organophosphonic acids containing one phosphonic acid group per molecule such as 2- hydroxyphosphonoacetic acid, 2-phosphonobutane-l,2,4-tricarboxylic acid, phosphonated oligomers and polymers of maleic and acrylic acids as well as co- oligomers and copolymers thereof.
• organophosphonic acids containing two or more phosphonic acid groups per molecule like diphosphonic acids such as alkylmethane-l-hydroxy-l,l-diphosphonic acids where the alkyl group may be substituted or unsubstituted and contain from 1 to 12 carbon atoms e.g. methyl- 1 -hydroxy- 1,1 -diphosphonic acid or propyl- 1-hy droxy- 1,1 -diphosphonic acid.
• amino compounds containing two or more N-alkylene phosphonic acid groups per molecule such as alkylamino- di(alkylene phosphonic acids) where the alkyl group can be substituted or unsubstituted and have from 1-12 carbon atoms e.g propyl, isopropyl, butyl, hexyl, or 2-hydroxyethyl and the alkylene group may have from 1 to 5 carbon atoms as well as amino-tri(alkylene phosphonic acids) such as nitrilo-tris-(methylene phosphonic acid) and nitrilo-tris-(propylene phosphonic acid).
• alkylamino- di(alkylene phosphonic acids) where the alkyl group can be substituted or unsubstituted and have from 1-12 carbon atoms e.g propyl, isopropyl, butyl, hexyl, or 2-hydroxyethyl and the alkylene group may have from 1 to 5 carbon
• alkylene diamine-tetra-(alkylene phosphonic acids) such as ethylene diamine-tetra-(methylene phosphonic acid), dialkylene triamine-penta-(alkylene phosphonic acids such as diethylene triamine- penta-(methylene phosphonic acid) and so on.
• Phosphorus free acidic substances include hydroxyacids which may be monocarboxylic acids with one or more hydroxyl groups such as glycolic acid, lactic acid, mandelic acid, 2,2-bis-(hydroxymethyl)-propionic acid, 2,2-bis- (hydroxymethyl)-butyric acid, 2, 2-bis-(hydroxymethyl)- valeric acid, 2,2,2-tris- (hydroxymethyl)-acetic acid and 3,5.dihydroxybenzoic acid, dicarboxylic acids with one or more hydroxyl groups such as tartaric acid and and tricarboxylic acids with one or more hydroxyl groups such as citric acid.
• hydroxyacids which may be monocarboxylic acids with one or more hydroxyl groups such as glycolic acid, lactic acid, mandelic acid, 2,2-bis-(hydroxymethyl)-propionic acid, 2,2-bis- (hydroxymethyl)-butyric acid, 2, 2-bis-(hydroxymethyl)- valeric acid, 2,2,2-tris- (hydroxymethyl)-acetic acid and 3,5.
• Phosphorus free acidic substances also include polymers of methacrylic acid, acrylic acid and maleic anhydride or maleic acid as well as copolymers thereof such as acrylate-acrylic acid copolymers, olefin-maleic anhydride copolymers like isobutylene-maleic anhydride copolymers, styrene-maleic acid copolymers and vinyl alkyl ether- maleic acid copolymers like poly(vinyl methyl ether-co-maleic acid).
• Phosphorus free acidic substances further include azoles and their derivatives containing two or more heteroatoms such as 1,2,3-benzotriazole, tolytriazole, benzothiazole, 2- mercaptobenzothiazole, benzimidazole, 2-mercaptobenzimidazole, benzoxazole, 2- mercaptobenzoxazole and (2-benzothiazolythio)succinic acid.
• azoles and their derivatives containing two or more heteroatoms such as 1,2,3-benzotriazole, tolytriazole, benzothiazole, 2- mercaptobenzothiazole, benzimidazole, 2-mercaptobenzimidazole, benzoxazole, 2- mercaptobenzoxazole and (2-benzothiazolythio)succinic acid.
• Basic substances include alkanolamines, which may be a monoalkanolamine, a dialkanolamine, a trialkanolamine, these being primarily the ethanolamines and their N-alkylated derivatives, l-amino-2-propanols and their N- alkylated derivatives. 2-amino-l-propanols and their N-alkylated derivatives and 3-amino-l-propanols and their N-alkylated derivatives or a mixture thereof.
• Suitable monoalkanolamines include 2-aminoethanol(ethanolamine), 2-(methylamino)-ethanol, 2-(ethylamino)-ethanol, 2-(butylamino)-ethanol, 1- methyl ethanolamine (isopropanolamine), 1 -ethyl ethanolamine, l-(m)ethyl isopropanolamine, n-butylethanolamine, cyclohexanolamine, cyclohexyl isopropanolamine, n-butylisopropanolamine, l-(2-hydroxypropyl)-piperazine, 4- (2-hydroxyethyl)-mo ⁇ holine and 2-Amino-l-propanol.
• di- alkanolamines examples include diethanolamine (2,2'-iminodiethanol), 3-amino-l,2-propanediol, 2-amino- 1,3 -propanediol, diisobutanolamine (bis-2-hydroxy-l-butyl)amine), dicyclohexanolamine and diisopropanolamine (bis-2-hydroxy-l -propylamine).
• An example of a suitable trialkanolamine is tris(hydroxymethyl)aminomethane.
• Cyclic aliphatic amines may also be used such as morpholine, piperazine and their N-alkyl derivatives as well as fatty amines. Mixtures of any of the above phosphorus containing, phosphorus free or amine substances are also suitable.
• azole derivatives with amine functionality such as 3-amino- 1,2,4-triazole.
• Preferred stabilizing or complexing agents include phosphorus acid, phosphoric acid, tri- and polyphosphoric acids and organophosphonic acids containing one or more phosphonic acid groups per molecule such as 2- hydroxyphosphonoacetic acid, together with monocarboxylic acids and dicarboxylic acids with one or more hydroxyl groups per molecule such as glycolic acid.
• Preferred stabilizing or complexing agents include azole derivatives, such as 1,2,3-benzotriazole, 2-mercaptobenzothiazole and (2-benzothiazolythio)succinic acid.
• Another embodiment of the present invention relates to a method of making a dispersion of surface modified inorganic particles including mixing the surface modified inorganic particles and a fluid and milling the inorganic particles to form particles having an average diameter of about ten microns or less, wherein the inorganic oxide particles are surface modified with polyvalent metal ions.
• dispersions of small particles where the dispersions contain inorganic particles are obtained in the presence of polyvalent cations by wet-milling techniques, with addition of the suitable acidic, basic or complexing substances described above prior to milling whereby pH is adjusted and/or cations are complexed.
• the cations are present intentionally or are present as a result of prior preparation techniques.
• the added substance may be a soluble or partially soluble component of the corrosion inhibiting composition that is to be milled and extra additions of the substance may not then be necessary. Stable dispersions are thereby obtained, avoiding or minimizing excessive viscosity build-up, reagglomeration of particles and hard settling that may otherwise occur during or after wet milling.
• the average particle sizes produced are about 10 microns or less and all or most of the particles in the dispersion may be less than 1 micron.
• the particles may be non-porous, substantially non-porous or porous according to the nature of the inorganic oxide used in the process or prepared during the overall process of preparing the inhibitor. In the light of the previous discussion, porosities may therefore vary up to about 3ml/g. Milling may commonly be carried out in an aqueous phase but may also be carried out in a non-aqueous phase.
• suitable solvents may be any of the known solvents commonly used in coatings applications such as alcohols, esters, ketones, glycol ethers, aromatic and aliphatic hydrocarbons, as well as aprotic solvents such as N- Methyl pyrrolidone, N-Ethyl pyrrolidone, Dimethyl sulphoxide, N,N- Dimethylformamide and N,N-Dimethylacetamide.
• the inorganic oxides may be transferred to any of the solvent classes mentioned above by techniques known in the prior art. Examples are those discussed in the Journal of Colloidal & Interface Science 197, 360-369, 1998 A. Kasseh & E. Keh, "Transfers of Colloidal Silica from water into organic solvents of intermediate polarities" and the Journal of Colloidal & Interface Science 208, 162-166, 1998 A. Kasseh & E.
• Keh "Surfactant mediated transfer of Colloidal Silica from water into an immiscible weakly polar solvent" or recited in US Patent Nos. 2,657,149, 2,692,863, 2,974,105, 5,651,921, 6,025,455, 6,051,672, 6,376,559 and GB Patent No. 988,330, the entire subject matter of which is incorporated herein by reference. Introduction of polyvalent cations, stabilizing and complexing components and/or combination with sparingly soluble salts may occur prior to solvent transfer or following solvent transfer.
• the corrosion inhibiting particles may be included in protective and adhesion promoting coatings and layers, such as surface pretreatments, surface films, anti-corrosive primers, adhesives and sealants and the present invention includes protective coatings and adhesion promoting coatings and layers containing corrosion inhibiting particles as described above.
• the protective coatings and adhesion promoting coatings and layers may be based on any of the known types of organic and inorganic chemistries used in anti-corrosion e.g.
• epoxy resins polyesters resins, phenolic resins, amino resins such as melamine- formaldehyde, urea-fomaldehyde or benzoguanamine resins, vinyl resins, alkyd resins, chlorinated rubbers or cyclised rubbers, acrylic and styrene-acrylic chemistries, styrene.butadiene resins, epoxy-esters, silicate based coatings such as zinc-rich silicates, sol-gel coatings based on alkyl silicates and/or colloidal silicas, films, treatments and coatings derived from organofunctional silanes, as well as acidic or alkaline metal pretreatment solutions and primer-pretreatment solutions.
• silicate based coatings such as zinc-rich silicates, sol-gel coatings based on alkyl silicates and/or colloidal silicas, films, treatments and coatings derived from organofunctional silanes, as well as acidic or alkaline metal pretreatment solutions and primer-pretreatment
• a 1OL Drais Laboratory Pearl mill (available from Draiswerke, Inc,) is filled with 1.2 Kg of ZrO 2 beads (0.6- lmm in diameter).
• An aqueous slurry of Shieldex ® C303 pigment (available from W. R. Grace & Co.), having an average particle size of 3-4 ⁇ m, to which is added a small amount of 2- hydroxyphosphonoacetic acid is circulated for 6 hours at a rotor speed of 2800rpm (slow setting) and at a pump speed of 40% of the maximum.
• 0.2% by weight of Acticide ® 1206 bacteriacide (available from Thor Chemicals) is mixed in.
• the suspension of Shieldex ® C303 pigment and water is stirred for 1 hour at room temperature before addition under mixing of the solution of 2-hydroxyphosphonoacetic acid. This causes the pH to drop from 8.42 to 8.04.
• the composition of the slurry in % by weight is Shieldex ® C303 pigment 16.21%; water 72.93%; 10.66% of a 5% aqueous solution of 2- hydroxyphosphonoacetic acid and 0.2% Acticide ® 1206 bacteriacide.
• a free flowing dispersion of Ca/SiO2 particles results, having an average particle size of about 0.3 ⁇ m which remains stable on storage for more than 90 days. 98% of the particles are less than l ⁇ m. Particle size is determined with a Mastersizer ® 2000 light scattering equipment available from Malvern Instruments.
• An anti-corrosive pigment is prepared in-situ by reacting together silica gel, having a particle size of 3-4 ⁇ m (available from W. R. Grace & Co.- Conn.), Ca(OH) 2 , and 2-hydroxyphosphonoacetic acid. The resultant mixture is then subjected to pearl milling for about 30 minutes in a laboratory Dispermat ® mill (available from DISPERMAT) using lmm glass beads at a rotor speed of l ⁇ OOrpm. This results in a free flowing dispersion of Ca/SiO 2 /HPA particles having an average particle size of about 2 ⁇ m.
• the composition of the slurry in % by weight is silica gel 5.60%; water 81.12%; 5.52% Ca(OH) 2 and 7.76% of a 50% aqueous solution of 2-hydroxyphosphonoacetic acid.
• the mixture is aged for 16 hours at 40 0 C prior to adding the solution of 2-hydroxyphosphonoacetic acid at a rate such that the pH does not drop below 9.
• the reaction mixture is aged at 90 0 C for 1 hour prior to cooling and milling.
• the particles in the milled dispersion do not reagglomerate after sitting for over 90 days, and the dispersion may be added to a variety of protective coating formulations.
• Shieldex ® C303 pigment alone since the dispersions of Examples 2 and 3 are not stable. In the absence of being able to apply coatings down to a thickness of a micron or so, tests are carried out in a water-borne acrylic coating applied by applicator bar to Sendzimir ® galvanized steel (i.e., Chemetall Test Panels) so as to obtain a dry film thickness of about 40 ⁇ m in order to assess whether the dispersion offers any improvements in anti-corrosive performance compared to Shieldex ® C303 pigment alone.
• the formulations employed are given below in Table 3, in which the dispersion is incorporated by simple stirring, whereas Shieldex C303 pigment is incorporated with the aid of glass beads in the normal way.
• the coated panels are scribed and subjected to salt spray (using ASTM Bl 17) for 240 hours, after which the panels are briefly rinsed, dried and evaluated within 30 minutes of withdrawal from the salt spray cabinet.
• the results are given in Table 1, where ratings are given on a scale of 0 to 5 in which 0 signifies no breakdown and 5 signifies complete breakdown.
• Salt spray results for Example 1 against Shieldex ® C303 pigment in a water-borne acrylic coating on galvanized steel (Ratings are from 0 to 5 with 0 being best)
• Example 4 Anti-corrosive tests are also carried out on Example 4.
• a zinc-free dispersion of the present invention is compared against a commercially available zinc based anti-corrosive pigment (Heucophos ® ZPO anticorrosive pigments available from Heubach GmbH) commonly used in water-borne acrylic coatings.
• Shieldex ® AC5 a commercially available zinc-free anti-corrosive pigment is also included in the testing as a reference.
• Coatings are applied by applicator bar to cold rolled steel (Q-Panels S412 available from the Q-Panel Co.) so as to obtain a dry film thickness of about 40 ⁇ m.
• the formulations employed are given below in Table 3, where again the dispersion is incorporated by simple stirring, but Heucophos ® ZPO pigment is incorporated with the aid of glass beads as referenced herein.
• Example 5 As in Example 5, the coated panels are scribed and subjected to salt spray (using test ASTM Bl 17) for 240 hours, after 7 days of drying at room temperature. Subsequently, the panels are briefly rinsed, dried and evaluated within 30 minutes of withdrawal from the salt spray cabinet. The results are given in Table 2, where again ratings are given on a scale of 0 to 5 in which 0 signifies no breakdown and 5 signifies complete breakdown.
• anti-corrosive properties of example 7 are determined as follows.
• Aluminium alloy 2024-T3 was used as the test electrode in a three electrode configuration employing a saturated Ag/AgCl reference electrode and a platinum counter electrode in which the sodium chloride containing dispersion is used as the electrolyte.
• a current-voltage curve is generated by sweeping 25OmV either side of the rest potential under potentiodynamic conditions using Gill ⁇ AC electrochemical corrosion test equipment (available from ACM Instruments).
• the slope of the curve 1OmV either side of the rest potential is used as a measure of corrosion inhibition in which the slope has units of resistance.
• Three comparisons are employed. The first involved adding 0.39g of NaCl under stirring to lOOg of LUDOX ® AM silica to produce a dispersion about 0.1M in NaCl without calcium or BTA.
• the second involved preparing a solution of calcium hydroxide (0.767g) and BTA (6.684g) in a 1:5 molar ratio in 0.1M NaCl (10Og) so that the resulting concentration of BTA is 6.3% by weight of BTA based on the total water content of the solution.
• the third is simply a 0.1M sodium chloride solution. The results are shown in Table 4.
• Example 7 and LUDOX ® AM silica provide evidence of corrosion inhibition on 2034-T3 compared to BTA alone and the blank, but only Example 7 provides stable inhibition as evidenced by a high slope and a smooth curve, where a jagged curve is indicative of alternating surface breakdown and repair.
• R L R L + k(Ru -R L ), where k is a variable ranging from 1% to 100% with a 1% increment, e.g., k is 1%, 2%, 3%, 4%, 5%. ... 50%, 51%, 52%. ... 95%, 96%, 97%, 98%, 99%, or 100%.
• any numerical range represented by any two values of R, as calculated above is also specifically disclosed. Any modifications of the invention, in addition to those shown and described herein, will become apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Paints Or Removers (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Colloid Chemistry (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Paper (AREA)
• Cosmetics (AREA)
• Silicon Compounds (AREA)

Priority Applications (13)

Applications Claiming Priority (2)

Publications (2)

Family

ID=40601416

Family Applications (1)

Country Status (18)

Cited By (2)

Families Citing this family (10)

Family Cites Families (67)

• 2008
  • 2008-11-19 MY MYPI2010002289A patent/MY160059A/en unknown
  • 2008-11-19 JP JP2010533514A patent/JP2011505233A/ja active Pending
  • 2008-11-19 KR KR1020107013369A patent/KR20100108523A/ko not_active Ceased
  • 2008-11-19 TW TW097144655A patent/TW200934837A/zh unknown
  • 2008-11-19 EP EP08852905.2A patent/EP2222793B1/en not_active Revoked
  • 2008-11-19 CL CL2008003433A patent/CL2008003433A1/es unknown
  • 2008-11-19 CN CN200880125399.9A patent/CN101918500B/zh not_active Expired - Fee Related
  • 2008-11-19 RU RU2010125233/05A patent/RU2010125233A/ru not_active Application Discontinuation
  • 2008-11-19 BR BRPI0819628-1A patent/BRPI0819628B1/pt not_active IP Right Cessation
  • 2008-11-19 CA CA2706138A patent/CA2706138A1/en not_active Abandoned
  • 2008-11-19 WO PCT/EP2008/009777 patent/WO2009065569A2/en not_active Ceased
  • 2008-11-19 MX MX2010005419A patent/MX2010005419A/es unknown
  • 2008-11-19 US US12/742,558 patent/US10385216B2/en active Active
  • 2008-11-19 KR KR1020167011117A patent/KR101927823B1/ko not_active Expired - Fee Related
  • 2008-11-19 AR ARP080105035A patent/AR069375A1/es unknown
  • 2008-11-19 ES ES08852905.2T patent/ES2648063T3/es active Active
  • 2008-11-19 PL PL08852905T patent/PL2222793T3/pl unknown
  • 2008-11-19 KR KR1020177034267A patent/KR20170135987A/ko not_active Withdrawn
  • 2008-11-19 AU AU2008328191A patent/AU2008328191B2/en not_active Ceased
• 2010
  • 2010-05-19 ZA ZA2010/03544A patent/ZA201003544B/en unknown
• 2014
  • 2014-02-17 JP JP2014027129A patent/JP6072711B2/ja not_active Expired - Fee Related

Also Published As

Similar Documents

Legal Events