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WO1999058274A1 - Modification de particules metalliques - Google Patents

Modification de particules metalliques Download PDF

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Publication number
WO1999058274A1
WO1999058274A1 PCT/US1999/006647 US9906647W WO9958274A1 WO 1999058274 A1 WO1999058274 A1 WO 1999058274A1 US 9906647 W US9906647 W US 9906647W WO 9958274 A1 WO9958274 A1 WO 9958274A1
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Prior art keywords
zinc
metal
lubricant
flake
particles
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PCT/US1999/006647
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English (en)
Inventor
Ronald R. Savin
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Priority to AU32080/99A priority Critical patent/AU3208099A/en
Publication of WO1999058274A1 publication Critical patent/WO1999058274A1/fr
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/06—Metallic powder characterised by the shape of the particles
    • B22F1/068—Flake-like particles
    • 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
    • C09D5/106—Anti-corrosive paints containing metal dust containing Zn
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B22F2009/043—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by ball milling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy

Definitions

  • This invention relates to the production of particulate metals. It particularly relates to modification of zinc for use in anti-corrosion compositions.
  • Zinc can be applied by a so-called galvanizing process in which the zinc is applied by, for example, hot dipping or electroplating.
  • Galvanizing employing pure zinc without a binder has provided the best protection with maximum corrosion resistance.
  • Galvanizing coating compositions also referred to as "zinc-rich primers"
  • Zinc-rich primers contain zinc metal particles and become oxidized only when exposed to the elements.
  • Conductivity of the galvanizing composition provides an excellent cathodic protection to steel (and which acts as the cathode, zinc being the anode) when exposed to a saline environment or other forms of oxidation caused primarily by water in its various forms, for example moisture, vapour or ice.
  • Zinc-rich primers have been considered to be optimum anti- corrosion coatings on iron or steel substrates but such compositions do have problems.
  • Zinc is often added to compositions just prior to use and mixed rapidly during application to prevent settling and clogging of equipment.
  • primers have traditionally been limited to application over blasted and untreated steel.
  • steel is often "passivated” . Passivation promotes adhesion to metal and includes the application of zinc phosphate or iron phosphate to the steel substrate.
  • Zinc rich primers are not usually applied over iron phosphated steel since these primers do not possess sufficient conductivity to provide cathodic protection to iron phosphated steel.
  • Zinc metal is used in coating compositions in particulate form.
  • Conventional forms of particulate zinc although effective in zinc coating compositions to provide cathodic protection, tend, as stated, do require high proportions of zinc to binder.
  • the object of the present invention is to provide improved metal particles and a more efficient method for the production of such metal particles .
  • a particular object of the invention is to provide a new form of zinc particle and a method of producing such particles. This aspect of the invention also provides improved coating compositions containing such particles.
  • compositions have been disclosed in which, in addition to the content of zinc, other components are added to modify the electrical conductive characteristics.
  • other components are added to modify the electrical conductive characteristics.
  • Patent No. US-A-4, 417 , 007 issued November 1983 to G. Slaensky et. al.
  • US Patent No. US-A-4 , 885, 324 issued December 5th, 1989 to Hegedus et. al .
  • US Patent No. US-A-4, 748, 194 issued May 1989 to Geeck
  • US Patent No. US-A-4, 621, 024 issued November 4th, 1986 to F.A. Wright
  • US Patent No. US-A-5, 182, 318 by the applicant of the present application, Canadian patent CA-A-2, 065, 828 and US
  • Patent No. US-A-5, 167,701 issued December 1992 to applicant of the present invention.
  • US Patent No. 4,411,742 issued October, 1983 to Donakowski et al., discloses a lubricant composition containing zinc and graphite although it has a higher resistance to corrosion.
  • the composition is applied as a co-deposit by electroplating zinc in the presence of an electrolyte containing zinc ions and bulk graphite.
  • the graphite saturates the zinc interface as it plates out.
  • US Patent No. 4,411,742 also discloses forming electro co- deposited zinc/graphite coatings, the graphite being present in the amount of 30 to 48% by weight of the co-deposit which is stated as being critical. However, the addition of graphite in such a composition reduces corrosion resistance.
  • the composition is an electrolytic co-deposit as distinct from a composition for use in providing primers or other coating compositions.
  • Organic coatings made using particulate zinc provide only limited protection to bare metal due to their much lower conductivity than zinc metal which is caused by the dielectric properties of organic resins.
  • the greater the conductivity the greater the area of adjacent bare steel that will be protected by the zinc metal.
  • the level of adjacent bare metal protection is largely proportional to its conductivity measured in Ohms/cm 2 . All galvanizing compositions prior to exposure will measure total conductivity of 0.00 Ohms/cm 2 at 75 micron deposition whereas zinc particulate-rich industrial and maintenance coatings will measure from 1 to several dozen Ohms/cm 2 of 75 microns based on the percentage of zinc particulate material and the particle size of the zinc utilised.
  • Conventional zinc is provided in the form of dust or powder.
  • the former is usually prepared by condensation of zinc vapour in an inert atmosphere.
  • the particle size is usually less than 20 microns.
  • Zinc powder is usually produced by breaking up a stream of molten zinc metal into droplets by impact of a pressurised stream of fluid, usually air, on the zinc stream. This process requires large volumes of fluid and collection techniques to collect any particles which do not settle out of the gas stream. Usually the particle size is from 20 microns to 60 microns.
  • Zinc rich primers particularly those which are organic film forming compositions manufactured with zinc dust (or zinc powder) tend to provide only thin adjacent protection to exposed bare metal (limited to a scribed area) . This is believed to be because of zinc dust's lower conductivity caused by surface oxidation .
  • a convenient method of testing is to drill several holes of 6-8mm through the primer coating to bare metal and expose the resulting primed panel to the ASTM B-117 salt-fog test.
  • ASTM test a primed scribed panel coated with primer over 100 bonderised or blasted steel is subjected to 5% sodium chloride salt-fog for a predetermined period.
  • the conventional ASTM method of testing may be misleading since the scribed area of bare metal exposed to salt fog is extremely thin and one may obtain impressive results because the primer produces deposits of zinc oxide, zinc carbonate (white rust) in the scribed area.
  • the modified test method allows anti-corrosion properties to be determined on less than 500 hours as compared to the thousands of hours previously necessary.
  • a lamellar form of zinc namely zinc flake
  • the milling flattens the zinc particles.
  • the usual starting material is zinc dust and the milling produces a flake of thickness of 1 micron or smaller and an aspect ratio ie . diameter to thickness of about 10. This type of wet milling is described in French Patent FR-A-1570616 British Petroleum (Chemical Abstract 72-45774)
  • the process has a number of disadvantages. It is not very rapid.
  • the materials of construction for the ball- milling must be chosen to avoid contamination.
  • the operation involves the use of a flammable fluid, for example a hydrocarbon such as mineral spirits, which creates environmental problems when it is removed.
  • a hydrocarbon such as mineral spirits
  • the hydrocarbon can amount to 40% volume must be evaporated.
  • the capital cost of a flaking plant is very high per unit of production. This and the small volume of flake manufactured by such a plant makes the cost of the material high which tends to limit its application.
  • the stearate in the product interferes with the compatibility of the zinc with the other components of the coating composition. This is believed to arise from the fatty component of the stearate.
  • apparent density is meant that the particles in bulk loose form have a weight for volume which may differ from the density of masses of the material. The spacing created between particles by reason of shape of particles alters the apparent density.
  • the resulting zinc flake proves to be more effective than unmodified zinc flake. It would appear that the inorganic lubricant, particularly carbon, especially graphite, is incorporated into the metal of the zinc particles at least to some degree whereby the resulting composition is a very effective zinc component in anti-corrosion compositions . This incorporation into the metallic structure appears also to be found with the other metals .
  • a method for the preparation of a metal material comprising a metal which is sufficiently malleable for its particles to flatten when subjected to mechanical milling, characterised in that it comprises a step in which a mixture of particles of the metal and a solid composition with lubricant properties is subjected to mechanical milling under substantially dry conditions until the metal is in the form of flakes.
  • a finely divided metal flake material characterised in that it comprises particles of a metal which is sufficiently malleable for particles thereof to flatten when subjected to mechanical milling and a solid inorganic lubricant, a major proportion of the lubricant being incorporated into the lattice structure of the metal .
  • the metal is zinc.
  • composition comprising zinc flakes and graphite or carbon black in which at least a proportion of the graphite is incorporated into the metallic structure of the zinc particles.
  • the invention also relates to an anti-corrosion coating composition containing the zinc/inorganic lubricant particulate material of the invention.
  • the balance of the composition comprises conventional components, eg. binders, curing agents and dispersants and similar products.
  • a method of preparing an anti-corrosion coating composition comprising the steps of (1) mixing zinc particles with particles of solid components with solid lubricant properties; (2) subjecting the mixture to mechanical milling under substantially dry conditions to render the particles into lamellar shape; and (3) combining said lamellar shaped particles into binder components to form a coating composition applicable to a substrate to form a corrosion resistant surface layer.
  • the metal particles and a dry inorganic lubricant are combined and mechanically milled together to produce metal flakes in such a way as to incorporate a major part of the lubricant intimately with the final metal particles.
  • zinc particulate material composition containing graphite is milled to incorporate a major proportion of the graphite or carbon black into the zinc flake particles.
  • lubricant material for example carbon
  • the inclusion of the lubricant material, for example carbon, into intimate combination in the zinc particle is an important feature of this aspect of the invention since simply combining zinc powder and free carbon, eg. graphite, while giving useful results requires high proportions of carbon, for example 30% by weight on binder and/or high proportions of zinc flake.
  • the lubricant is a fluorocarbon polymer, eg. a polyfluoroethylene .
  • a lubricant which is a mixture of fluorocarbon polymer (eg. polyfluoroethylene) , carbon (eg. graphite) and, possibly, a silica such as mica.
  • fluorocarbon polymer eg. polyfluoroethylene
  • carbon eg. graphite
  • silica such as mica
  • The. introduction of the lubricant, especially graphite, apart from producing a superior final composition, has a dramatic effect on the time and steps necessary for the milling of the metal to a flake form.
  • the ability to operate a mill, for example a pebble or ball mill, for only a few hours (down to about 5 hours with a large commercial mill) is considerably less time than present milling techniques and therefore significantly reduces the cost of flake.
  • the method of the invention is suitably performed using "dry milling", ie. milling in the substantial absence of liquid media. A suitable milling operation is described in detail in Example 14.
  • Solid lubricants are a well recognised group of lubricants. They are distinguished from liquid or semi-liquid lubricants such as oils and greases (for example hydrocarbons or silicones) .
  • inorganic lubricants there are generally recognised to be three classes of solid lubricant materials :
  • Layer-lattice solids the most common are carbon materials such as graphite or carbon black but other lattice structural materials such as molybdenum disulfide, tungsten disulfide, mica, boron nitride, borax, silver sulfate, cadmium iodide and lead iodide have the necessary structure. Whether all of these are usable in all versions of this invention will perhaps require testing to ensure there is no interference with properties relevant to the intended use of the final metal flake but such testing is simple.
  • Soft solids these include white lead, lime, talc, bentonite, silver oxide and lead monoxide. As in the first group, there may be some of these which, although lubricants, would not be suitable because of intended use of the flake.
  • Organic materials which can be employed as solid lubricants are usually divided into two classes -
  • Preferred for this invention are polymeric, ie . high molecular weight, film materials particularly polyhaloalkylenes
  • polyfluoroethylenes such as polytetrafluoroethylene or polychlorofluoroethylene .
  • These high molecular weight synthetic polymers, especially polytetrafluoroethylene have been found to provide excellent lubrication for the milling. With zinc they have been found to produce desirable visual properties.
  • fluorocarbon polymers are relatively expensive.
  • the expense of using them as lubricants can be reduced by using as a lubricant a mixture with one or more inorganic lubricants, for example a mixture of polytetrafluoroethylene, graphite and mica has been very effective or many applications .
  • a preferred mixture is a 1:1:1 composition.
  • interference functionality signifies that the solid lubricant is free of such groups as would significantly increase the resistivity of the zinc flake product requiring a larger amount of zinc flake in the coating composition and also diminishes the combinability of a zinc flake with coating composition components as compared to dry milling with graphite or a high molecular weight polymeric dry grinding lubricant such as polytetrafluoroethylene.
  • Another problem concerning the utilization of a grease such as stearic acid is that it is reactive with waterborne silicates (potassium, sodium, lithium etc. , ) seriously reducing the potlife when the zinc flake is added.
  • Graphite and flouro carbons have no negative effect on binders with a high pH such as the silicates and other waterborne binders .
  • Solid lubricants of this class which contain interference functionality are therefore excluded.
  • Simple solid hydrocarbons as waxes are probably also not usable as they are not resistant to the heat generated in the milling process.
  • High molecular weight (polymeric) silicones may be suitable.
  • a small amount of a dispersing agent for example a stearate, may be added to the lubricant (see Example 4) merely to assist in dispersing lubricant in the solid mixture of components .
  • This is substantially less than amounts used in wet milling and, in itself, would not be sufficient to act as a lubricant.
  • the requirement of absence of interference functionality can therefore apply to either the whole of the material of solid lubricant or the overall characteristics of a combination of materials .
  • a solid lubricant as used in this invention must therefore be (particularly for organic lubricants) one which is appropriate
  • An inorganic lubricant can sometimes be referred to as a lubricant with electrical enhancing properties. It is known to incorporate certain inorganic materials which have an effect on the cathodic protection which zinc provides in anti-corrosion compositions. Such materials include forms of carbon, forms of silica, particularly hydrophobic silicas and metallic oxides, for example aluminum oxide. For use in this invention such cathodic activity enhancing inorganic materials must have some lubricant properties which allows milling of the zinc particles to flake form while avoiding fusion of the zinc. Any inorganic material which provides the appropriate lubricant action for dry milling zinc can be employed and it does not appear necessary to employ a compound which has a negative effect on the cathodic properties of zinc. Determination of appropriate materials is not difficult given the teaching of this application and the knowledge of those skilled in the art as to dry lubrication.
  • inorganic lubricant is likely to depend only on the lubricant properties .
  • Certain inorganic lubricants for example carbon
  • carbon can be introduced into the zinc flake particles by forming a zinc/carbon composition from which particulate flake zinc is formed under conditions in which at least some of the carbon present is intimately incorporated into the metallic structure of the final zinc particles.
  • the carbon could be in the form of graphite or conductive carbon black.
  • carbon is the preferred inorganic lubricant, other lubricants can of course be employed including certain silica compounds and certain metal oxides . Suitable materials as lubricants are known to those working in this field.
  • the zinc metal structure appears to be analogous to alloy formation, that is the inorganic lubricant molecules or groups of molecules are entrained into the zinc metal lattice structure so as to be inseparable by normal mechanical means.
  • a zinc powder or zinc dust is combined with carbon and milled, particularly by ball milling.
  • the initial zinc powder or zinc dust can have the particle sizes for zinc dust of less than 20 microns and for zinc powder 10 to 60 microns, zinc dust being preferred.
  • the lubricant carbon particularly employed can be various forms of carbon but preferred is graphite of particle size of from 3 to 30 microns or conductive carbon black having particle size of from 1 to 3 microns (or even less) .
  • Other lubricants particularly organic lubricants such as polyfluoroethylene will have similar particle sizes .
  • the proportion of lubricant added will depend on the desired properties of the final composition. Particularly when the carbon is added by milling of zinc to form a flake there should be enough carbon added to act as a lubricant in the milling process in addition to its function in the final composition. For most lubricants including organic lubricants the amount added will be determined solely by the amount which achieves flaking in a reasonable time. A proportion of 1 to 10% by weight lubricant to metal appears to be very effective. For zinc to carbon 2 to 5% by weight is preferred and the optimum range is 3 to 5% by weight . The same ranges apply to organic lubricants .
  • milling processes can be employed including ball mills, pebble mills and other mills used for making flake material, particularly zinc flake.
  • the mill will be one in which the impact of the milling means especially grinding media reduces the thickness of the zinc particle to give flake form and not merely a mill which reduces particle size.
  • Such mills are well known to those skilled in the art.
  • substantially dry conditions indicates that a small amount of liquid may be present at least initially to assist in blending the mixture, ie . distributing the lubricant over the metal but is very substantially different from the use of large volumes of solvent in previous milling of flake in which the solid materials are dispersed in the solvent/liquid phase. Under the substantially dry conditions of the process of the invention it is likely that any solvent will disappear during milling.
  • the process of the invention can be applied to other metals, for example brass possibly for use in water treatment techniques, copper, silver and aluminum.
  • the metal should be one which is sufficiently malleable for the particles to substantially flatten upon milling. The process produces a low apparent density product.
  • the resulting composition can be employed in coating compositions, particularly primers, for application to surfaces which are subject to corrosion.
  • coating compositions particularly primers
  • Such compositions contain binder resins, zinc anti-corrosive agent and other conventional or standard components of such compositions.
  • the flake products obtained by the process of the invention have provided zinc rich epoxy primers with a zinc flake to binder ratio of approximately 3 to 1 which have provided protection for in excess of 30 days, revealing no rust in the 6-8mm drilled holes over treated, passivated and blasted steel. All conventional zinc rich organic primer controls with a 9 to 1 zinc to binder ratio failed this test.
  • Colour Development - Primers containing zinc flake can be tinted to match most medium tone industrial primers.
  • VOC's Volatile Organic Components
  • a particular advantage of the modified zinc composition of the invention is that in milling the components (e.g. resin etc.) for a coating composition, the possibility of fusion of zinc
  • This avoidance of fusion or sintering can eliminate or at least substantially reduce the need for anti- sintering agents particularly for powder coating compositions .
  • Binder resins used in compositions into which the zinc flake products produced by the invention are introduced will include alkyl silicates, zinc silicates, epoxy resins (powder and non- powder) and well known equivalents of these resins, including epoxy esters or polyester resins. Polyester powder resins may not be appropriate for solvent based compositions since they do not generally dissolve in common solvents .
  • a curing agent/hardener for example a bisphenol epoxy resin/diethylene triamine adduct together with propylene glycol monourethyl ether, N-butyl alcohol, toluene and di- ethylene triamine.
  • a flow control agent for example a polyacrylate and an electro-static charge modifier, for example aluminum oxide.
  • the resin binder can be any of the well known resins which are soluble or easily dispersible in the solvent, for example an epoxy powder.
  • Epoxy resins are the reaction products of epihalohydrin and phenols and hardening or crosslinking agents may be provided which contain functional groups reacting with the epoxy function.
  • the preparation of epoxy resins and crosslinking reactions are described in US Patent 3,954,693 issued May 1976 to C.C. Fong to which reference is made and the disclosure of which is incorporated by reference.
  • an epoxy powder as used in compositions containing zinc compositions of the invention have epoxide values (equivalent weight) of from 425 to 1000, more preferably 450 to 800.
  • Another binder can be an alkyl silicate, for example ethyl silicate dissolved in ethanol (ethyl polysilicate/ethylene glycol monoethylether/ethanol) .
  • a catalyst may be required to accelerate reaction between the silicate, the zinc and substrate and also a wetting agent can be employed.
  • a particularly useful binder which may have unusual aspects in the present invention is a zinc silicate.
  • This could provide a water-borne composition and in particular a water-borne reactive primer which could even replace electrodeposition of zinc.
  • the composition would comprise zinc silicate as binder and the flaked zinc produced by this invention.
  • Coatings of the present invention are particularly suited for use as cathodic coatings, zinc containing substance constituting the conductive phase when used as a "sacrificial anode" .
  • Coating compositions containing zinc compositions can be used for protection against corrosion on substrates including those in:
  • guardrails 5.
  • corrugated metal and buildings having units constructed from such metal;
  • compositions could be used in anti-corrosion compositions for application to brass, aluminum, and other metals subject to corrosion.
  • a surprising effect of the invention is that coating compositions containing the modified zinc composition of the invention provide improved cathodic protection to so-called treated or passivated steel.
  • Such steel ie. steel treated with, for example, zinc or iron phosphates, represent virtually the majority of painted steel utilised in industrial applications.
  • the zinc rich primer compositions presently employed do not provide protection to such passivated steel, ie. so-called white rust protection and are generally applied over blasted steel for industrial application.
  • Steel which is to be painted for anti- corrosion protection is customarily sand blasted, for example when used in bridges, dams, ships, storage tanks etc.
  • the inclusion of the carbon into intimate combination within the zinc particle is a particularly important feature of this aspect of the invention since simply combining zinc powder and free carbon, eg. graphite, while giving useful results requires high proportions of carbon, for example at least 30%, and/or high proportions i.e. from 30 to 60% by weight on binder that is 3 to 6% weight on a final coating composition as compared to 2% or less by weight with the present invention of zinc flake modified with carbon.
  • Coating compositions of the invention can contain proportions of the zinc material in amounts conventional for such compositions, for example, over 5 parts by weight zinc to 1 part binder but in one preferred aspect of the invention the amount of zinc can be less than 65% by weight of the dry components (excluding solvent/liquid) .
  • An important attribute of the zinc flake particulate product is its low apparent density and the effect of this density on the composition.
  • the density of the dust as a result of the milling was as follows :-
  • the milled pigment changed during milling from a fine grey dust to a metallic flake with a golden hue.
  • the resulting milled material was combined with a typical phenolic epoxy primer used in conventional primer compositions in the proportion of 3 parts of the modified zinc dust to 1 part binder by weight.
  • a control was prepared using 9 parts unmodified zinc dust to 1 part epoxy phenolic binder.
  • the two primers were separately applied over cold rolled steel panels and iron phosphated panels under the test conditions of ASTM B-117 (salt fog) . The panels were then exposed for 500 hours.
  • test panels coated with the modified zinc composition of the invention ie. the milled zinc/graphic composition exhibited zero corrosion over the cold rolled steel and iron phosphated steel.
  • the conventional composition containing unmodified zinc also exhibited zero corrosion in the scribed areas of cold roll steel but rusted within hours over the iron phosphated panels.
  • Example 1 The process of Example 1 was repeated but using instead of zinc dust a #1239 zinc powder produced by Zinc Corporation of America. The milling period was reduced from 32 hours to 24 hours and provided the same apparent density at the end of that time. The resulting product zinc-graphite powder had a more silvery appearance somewhat similar to conventional flake manufactured using inert hydrocarbon and stearic acid lubricant.
  • Example 1 The process of Example 1 was repeated employing two forms of commercial carbon black, one produced by Degussa and the other by Colombian Carbons. The resulting zinc/carbon compositions demonstrated the same results as outlined in Examples 1 and 2.
  • Example 1 was repeated using 300g of Zinc Corporation of America Zinc powder #1239, average particle size 15 microns, 3% by weight A99 graphite and 1% or 3g of stearic acid using a grinding media of 20.6 mm (13/16 inch) pebbles of approximately 2.7 kg (61bs), ie. 2.7 kg of pebble, 312g pigment. After 12 hours of milling the pigment had a bright leaf appearance similar to that produced by conventional milling techniques for much longer times but with a density of 2g/ml 3 . Further milling for 6 hours provided a product which was consistently flake like but produced an apparent density less than 1.5g/ml comparable with the best conventional commercial products.
  • Example 2 The modified zinc composition produced in Example 1 was incorporated into coating compositions as follows :-
  • compositions in the above Examples produced final coatings with excellent anti-corrosion properties despite the reduction in content of zinc.
  • Silver powder is subjected to a treatment as in Example 10.
  • a final flaked product is obtained which is of reduced apparent density.
  • Example 1 is repeated with, as inorganic lubricants:
  • the conventional composition (zinc dust/mica) showed considerable corrosion within 48 hours.
  • composition with the zinc flake of the invention resisted corrosion for a much longer time; unaffected after 200 hours.
  • the mixture that had been transformed into zinc flake was completely vacuumed from the ball mill leaving only the grinding media within the mill. All objectionable particle sizes were separated by a Vorti-Sieve over which a specific mesh screen had been placed to prevent oversized particles from inclusion in the final product. The produced zinc flake was then packaged for sale or distribution.
  • Zinc dust (a commercial zinc dust Purity® 15G supplied by North American Zinc Company (Purity Zinc Metals Division) and average particle size 10 microns) was mixed thoroughly with 2 percent by weight of zinc of polytetrafluoroethylene of specific gravity 2.15 melt point 320°C supplied under the trade name Fluoro A by Shamrock Technologies Inc., Pacific St., Newark, New Jersey
  • Example 15 was repeated using as lubricant a blend of the polytetrafluoroethylene M290 (1% by weight of zinc) , graphite

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Abstract

On broie des poudres de métal susceptibles de subir un tel traitement, du zinc notamment, avec un agent lubrifiant de manière à former des paillettes. Le produit final obtenu revient bien meilleur marché qu'il n'en va avec les procédés classiques de transformation en paillettes. La densité apparente de ce produit est basse et, lorsque le métal est du zinc et qu'il est incorporé à un enduit résistant à la corrosion, on obtient un produit supérieur à ceux obtenus en utilisant les poudres de zinc habituelles. Le rapport pigment zincifère/liant est, notamment, réduit. Les agents lubrifiants solides sont des lubrifiants inorganiques, notamment du carbone, du graphite par exemple, ou des lubrifiants organiques tels que des polymères filmogènes, des polyfluoréthylènes par exemple, mais non des substances comportant des groupes de surface actifs comme les savons, par exemple. Si le métal est du zinc et que l'agent lubrifiant soit du graphite ou du noir de carbone, il est possible d'incorporer ledit agent lubrifiant à la structure réticulée du métal pour obtenir un nouveau type de paillettes. ettes.
PCT/US1999/006647 1998-05-08 1999-03-25 Modification de particules metalliques Ceased WO1999058274A1 (fr)

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AU32080/99A AU3208099A (en) 1998-05-08 1999-03-25 Modification of metallic particles

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EP1348740A1 (fr) * 2002-03-27 2003-10-01 Eda Yapi Sisitemleri Ithalat Ihracat San. Ve Tic. Ltd. Sti Colorant antioxydant resistant a haute temperature
US6638628B2 (en) 2001-04-20 2003-10-28 Ronald R. Savin Silicate coating compositions
WO2007142599A1 (fr) * 2006-06-08 2007-12-13 Nord-Lock Ab Procédé pour recouvrir une rondelle de verrouillage et rondelle de verrouillage recouverte
US20100107816A1 (en) * 2008-10-30 2010-05-06 Henning Zoz Method of making metal flakes
WO2014032844A1 (fr) 2012-08-29 2014-03-06 Hempel A/S Compositions de revêtement primaire anticorrosion à base de zinc comprenant des sphères de verre creuses et un pigment conducteur
CN106715620A (zh) * 2014-09-26 2017-05-24 中国涂料株式会社 防锈涂料组合物及其用途
US20180126455A1 (en) * 2015-04-13 2018-05-10 National Institute of Technology Flat metal particle, molded article having flat metal particle, method for manufacturing flat metal particle, and method for manufacturing metal plate
CN108515185A (zh) * 2018-04-25 2018-09-11 北方工业大学 石墨烯包覆片状金属粉体材料及其制备方法
US11718762B2 (en) 2015-12-17 2023-08-08 Ppg Industries Ohio, Inc. Impact resistant coating compositions
WO2023237772A1 (fr) 2022-06-10 2023-12-14 Eckart Gmbh Particules de zinc noir, leur procédé de production, et utilisation
US11898060B2 (en) 2014-03-05 2024-02-13 Hempel A/S Anti-corrosive zinc primer coating compositions

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US6638628B2 (en) 2001-04-20 2003-10-28 Ronald R. Savin Silicate coating compositions
EP1348740A1 (fr) * 2002-03-27 2003-10-01 Eda Yapi Sisitemleri Ithalat Ihracat San. Ve Tic. Ltd. Sti Colorant antioxydant resistant a haute temperature
CN104988515A (zh) * 2006-06-08 2015-10-21 诺德锁具公司 涂覆锁紧垫圈的方法和具有涂层的锁紧垫圈
WO2007142599A1 (fr) * 2006-06-08 2007-12-13 Nord-Lock Ab Procédé pour recouvrir une rondelle de verrouillage et rondelle de verrouillage recouverte
US8216076B2 (en) 2006-06-08 2012-07-10 Nord-Lock Ab Method for coating washers for locking and coated washer for locking
US20100107816A1 (en) * 2008-10-30 2010-05-06 Henning Zoz Method of making metal flakes
US10214818B2 (en) 2012-08-29 2019-02-26 Hempel A/S Anti-corrosive zinc primer coating compositions comprising hollow glass spheres and a conductive pigment
WO2014032844A1 (fr) 2012-08-29 2014-03-06 Hempel A/S Compositions de revêtement primaire anticorrosion à base de zinc comprenant des sphères de verre creuses et un pigment conducteur
CN104619792A (zh) * 2012-08-29 2015-05-13 赫普有限公司 包含空心玻璃球和导电颜料的防腐蚀锌底漆涂料组合物
WO2014033237A1 (fr) * 2012-08-29 2014-03-06 Hempel A/S Compositions de revêtement primaire anticorrosion à base de zinc comprenant des sphères de verre creuses et un pigment conducteur
JP2015533870A (ja) * 2012-08-29 2015-11-26 ヘンペル エイ／エス 中空ガラス球状体と導電性顔料とを含有する防食亜鉛プライマー塗料組成物
AU2013307601B2 (en) * 2012-08-29 2016-09-15 Hempel A/S Anti-corrosive zinc primer coating compositions comprising hollow glass spheres and a conductive pigment
RU2642665C2 (ru) * 2012-08-29 2018-01-25 Хемпель А/С Противокоррозионные композиции для цинкосодержащего грунтовочного покрытия, содержащие полые стеклянные сферы и проводящий пигмент
EP3913024A1 (fr) 2012-08-29 2021-11-24 Hempel A/S Compositions de revêtement d'apprêt de zinc anticorrosion comprenant des sphères de verre creuses et un pigment conducteur
US10060039B2 (en) 2012-08-29 2018-08-28 Hempel A/S Anti-corrosive zinc primer coating compositions comprising hollow glass spheres and a conductive pigment
CN104603213A (zh) * 2012-08-29 2015-05-06 赫普有限公司 包含空心玻璃球和导电颜料的防腐蚀锌底漆涂料组合物
US12384922B2 (en) 2014-03-05 2025-08-12 Hempel A/S Anti-corrosive zinc primer coating compositions
US11898060B2 (en) 2014-03-05 2024-02-13 Hempel A/S Anti-corrosive zinc primer coating compositions
CN106715620B (zh) * 2014-09-26 2019-09-10 中国涂料株式会社 防锈涂料组合物及其用途
EP3199605A4 (fr) * 2014-09-26 2018-04-25 Chugoku Marine Paints, Ltd. Composition de peinture antirouille, et mise en uvre de celle-ci
CN106715620A (zh) * 2014-09-26 2017-05-24 中国涂料株式会社 防锈涂料组合物及其用途
US20180126455A1 (en) * 2015-04-13 2018-05-10 National Institute of Technology Flat metal particle, molded article having flat metal particle, method for manufacturing flat metal particle, and method for manufacturing metal plate
US11718762B2 (en) 2015-12-17 2023-08-08 Ppg Industries Ohio, Inc. Impact resistant coating compositions
US12275861B2 (en) 2015-12-17 2025-04-15 Ppg Industries Ohio, Inc. Impact resistant coating compositions, multi-layer coating systems, and substrates at least partially coated with such compositions
CN108515185A (zh) * 2018-04-25 2018-09-11 北方工业大学 石墨烯包覆片状金属粉体材料及其制备方法
WO2023237772A1 (fr) 2022-06-10 2023-12-14 Eckart Gmbh Particules de zinc noir, leur procédé de production, et utilisation

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