WO2006041658A1

WO2006041658A1 - Encapsulated metallic-look pigment

Info

Publication number: WO2006041658A1
Application number: PCT/US2005/034344
Authority: WO
Inventors: Gerald F. Billovits; Sarada P. Namhata; Dominique Maes; William C. Sumner, Jr.
Original assignee: Dow Global Technologies Inc.
Priority date: 2004-10-08
Filing date: 2005-09-22
Publication date: 2006-04-20
Also published as: TW200621902A

Abstract

Disclosed is an encapsulated metallic-look pigment, methods to prepare, and uses thereof. Also disclosed are injection molded articles comprising a thermoplastic and the encapsulated metallic-look pigment which show improved weld lines over injection molded articles comprising a thermoplastic and conventional metallic-look pigments.

Description

ENCAPSULATED METALLIC-LOOK PIGMENT

FIELD OF THE INVENTION

This invention relates to an encapsulated metallic-look pigment, methods to prepare, and uses thereof.

BACKGROUND OF THE INVENTION

The metallic look has become very popular in applications as varied as toys, makeup, electronic devices, and automobile body panels. Metallic-look pigments in general, and aluminum flake in particular, are widely used to produce appearances of the type which have a lustrous effect. Lustrous effects arise due to directional reflections of metallic-look pigment particles which have predominantly a two-dimensional shape and alignment. Two-dimensional refers to particles that are actually three-dimensional, but the thickness is small.

However, due to the alignment of metallic-look pigments, for example parallel to the viewing surface, in cosmetics, paints, surface coatings, and plastic applications, multiple reflections can cause different (that is, undesirable) appearances depending on the orientation of the metallic-look pigment in the particular application and/or the angle at which the application is viewed.

For example, one of the main goals of makeup or foundations is to prevent the appearance of wrinkles on the skin by manipulating how light is reflected. At present, metallic-look pigments are used primarily in special cosmetic products and not for daily use by the mainstream users. Their use is limited because there is a wide spread belief that the luster, or the high specular reflection, resulting from the parallel alignment of metallic-look pigments would increase the appearance of wrinkles. For example, see U.S. Patent No. 6,511 ,672 which discloses a cosmetic composition comprising a treated alumina platelet combined with at least two other particles.

In paints and surface coatings the visual effect wherein the color depth varies according to the angle of viewing is referred to as "flip" or "flop". Depending on the application and desired appearance, flip/flop may be an undesirable effect. A description of the origin of this effect and its measurement can be found in U.S. Patent No. 4,590,235.

Another shortcoming of metal pigments is that they are not generally stable in aqueous or water based paints and inks. In aqueous environments, the surface of metal pigments can be altered chemically, which over time can result in adverse visual effects such as loss ot shine and brilliance, tor example, see U.S. Patent No. 5,332,767 where a metallic pigment is coated with a thin layer of a synthetic resin.

Until now, it has been very difficult to produce a plastic article having an acceptable metallic appearance. Metallic-look pigment particles, most typically aluminum flake, have been dispersed in plastics to create a metallic appearance, but there are several disadvantages to this method.

One such disadvantage is that incorporation of metal pigments into polymers may cause degradation of the polymer mechanical properties. For instance, dispersing aluminum flake into polycarbonate will significantly decrease the impact strength of the polycarbonate.

Another shortcoming is that injection molded thermoplastic articles comprising metallic-look pigment particles have visibly pronounced weld lines (sometimes referred to as knit lines). A weld line is defined as the layer or region within the polymer that is generated when the melted polymer that contains the metallic-look pigment particle flows and merges from different directions in the injection mold, for example when the melted polymer flows around a pin or insert within the mold. As described in Metallic Pigments in Polymers by Ian Wheeler, the alignment of the metal-look pigments in the injection molded article is generally in the direction of polymer flow which is parallel to the surface of the molded article. However, the alignment of metal-look pigments at the weld line is generally perpendicular to the surface of the molded article. It is believed that the visibly pronounced weld line results from light reflecting differently from metal-look pigments aligned parallel versus ones aligned perpendicularly. Attempts to resolve this shortcoming have met with limited success, for example see JP 9194738, JP 8041284, JP 11279434, and U.S. Patent Application No. 2002/0120051. U.S. Patent Application No. 2004/0146641 discloses substantially spherical-shaped beads comprising metallic-look pigment particles and a method to prepare said beads. Unfortunately, the method produces a mixture of beads with and without metallic-look pigment particles along with a substantial amount of residual, unencapsulated metallic pigment. The yield of beads comprising one or more metallic-look pigment particles is low and requires an arduous, many step process to separate the desired product from the unfilled beads and unmodified metallic pigment. In the absence of this separation step, polymeric resins colored by the pigments so prepared still exhibit weld, meld and other flow lines. It would be highly desirable to provide a metallic-look pigment which when employed in cosmetic applications would not increase the appearance of wrinkles when applied to the skin, which would demonstrate good stability to aqueous environments, which would not produce the flip/flop visual effect in paints and surface coatings, and when used in plastics, which would not degrade the plastic's mechanical properties and, especially in injection molded thermoplastic articles, which would not produce visibly pronounced weld lines. Further, it would be highly desirable to have a process to make such metallic-look pigments in high yield without the need for expensive, time consuming separation/purification schemes. SUMMARY OF THE INVENTION

One embodiment of the present invention is an encapsulated metallic-look pigment comprising at least one metallic-look pigment particle and an encapsulating material surrounding at least part of the metallic-look pigment particle, wherein the metallic-look pigment particle is coated with a functionalizing compound. Preferably the encapsulated metallic-look pigment has an isometric shape having dimensions X, Y, and Z in three spatial directions, and each dimension is within +/- 25 percent of the other two dimensions. Preferably the metallic-look pigment particle is a metal pigment, a metal oxide-coated glass platelet pigment, a goniochromatic lustrous pigment, an interference pigment, a pearlescent pigment or a liquid-crystal pigment. Preferably, the functionalizing compound is a titanium coupling agent, an aluminum coupling agent, an aluminum chelating agent, a mineral oil, a silicon containing compound, a molecule comprising a long alkyl chain and a polar end group, or mixtures thereof, more preferably the functionalizing compound is a silicon- organic compound. Preferably, the encapsulating material is glass, an inorganic crystal, a thermoset plastic, or more preferably a thermoplastic. Preferably the encapsulated metallic- look pigment is a polyhedron, a cube or more preferably a sphere.

Another embodiment of the present invention is a process to make an encapsulated metallic-look pigment comprising the steps of coating a metallic-look pigment particle with funtionalizing compound, encapsulating the coated metallic-look pigment particle in an encapsulating material, preferably the encapsulated metallic-look pigment has an isometric shape having dimensions X, Y, and Z in three spatial directions, and each dimension is within +/- 25 percent of the other two dimensions. Preferably the encapsulating material is a suspension polymerizable thermoplastic. Preferably the process further comprising the steps of (i) forming a reaction mixture by (a) dispersing the coated metallic-look pigment particle in an organic medium containing one or more monomers to form a pigment/organic monomer slurry, (b) adding the pigment/organic monomer slurry to an aqueous system containing one or more suspension stabilizing agents forming a two phase hydrophilic/hydrophobic mixture, and (c) agitating, by shearing, mixing, etc., the two phase hydrophilic/hydrophobic liquid mixture to break up the pigment/monomer slurry into small droplets; (ii) initiating polymerization of the small droplets in the reaction mixture by increasing the temperature of the system to a level where autopolymerization begins in the monomer; and after polymerization has been completed, (iii) isolating the encapsulated metallic-look pigment as a wet cake, for example by centrifuging or filtering the reaction mixture, washing the wet cake with water to remove the suspending agent, and drying the retained solids to produce a free flowing solid. Preferably the process further comprises the step of (d) adding a free radical initiator to the reaction mixture and/or (e) adding one or more bi- or multifunctional species which cause the polymerizing droplets to gel or crosslink into a network structure. In a further embodiment of the present invention, the encapsulated metallic-look pigment is incorporated into a thermoplastic, a thermoset plastic, a paint, an ink, a toner, a cosmetic, a glue, or a paste.

Yet another embodiment of the present invention is a cosmetic composition comprising the encapsulated metallic-look pigment, a paint composition comprising the encapsulated metallic-look pigment, an ink composition comprising the encapsulated metallic-look pigment, an toner composition comprising the encapsulated metallic-look pigment, a thermoset plastic composition comprising the encapsulated metallic-look pigment, and preferably a thermoplastic composition comprising the encapsulated metallic- look pigment. Yet a further embodiment of the present invention is a fabricated plastic article from a thermoset plastic composition comprising an encapsulated metallic-look pigment and/or a thermoplastic composition comprising an encapsulated metallic-look pigment. Preferably the fabricated thermoplastic article is produced by injection molding, blow molding, extrusion, thermoforming, or combinations thereof. Preferably the fabricated plastic article is an automotive article, a lawn and garden article, a boat article, a snowmobile article, a personal water craft article, an enclosure for a computer, an enclosure for a computer accessory, an enclosure for a printer, an enclosure for a copier, an enclosure for a fax machine, an enclosure for a cell phone, an enclosure for a hand held personal data assistant, an enclosure for a television set, an enclosure for a audio system, a housing for a telephone, a housing for a small electrical appliance, a housing for an electrical tool, a washing machine cover, a dryer cover, a refrigerator cover, a freezer cover, a dish washer cover, a toy, a comb, a brush handle, a tooth brush handle, a cosmetic container, a ski boot, a sink, a toilet, a bath surround, a shower surround, or furniture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. l is a schematic representation of a spherical shaped encapsulated metallic- look pigment comprising one metallic-look pigment particle in an encapsulating material.

FIG. 2 is a schematic representation of a spherical shaped encapsulated metallic- look pigment comprising several randomly oriented metallic-look pigment particles in an encapsulating material.

FIG. 3 is a photograph of an injection molded thermoplastic article comprising a conventional metallic-look pigment.

FIG. 4 is a photograph of an injection molded thermoplastic article comprising the encapsulated metallic-look pigment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The metallic-look pigment particles 1 that are suitable for the encapsulated metallic- look pigment 2 of the present invention are platelet-shaped (sometimes referred to as flake shaped) pigments, such as metal pigments, metal or metal oxide-coated glass platelet pigments, goniochromatic lustrous pigments, interference pigments, pearlescent pigments, liquid-crystal pigments, or any other organic or inorganic platelets either coated or uncoated which provide a metallic-look.

Metal pigments comprise platelets or flakes of metals such as aluminum, copper, zinc, tin, gold, nickel, iron, chromium, and alloys thereof, such as brass, bronze, stainless steel, and in particular aluminum and gold-bronze alloys. The surface of the metal platelets can be passivated or provided with a protective layer, for example, of metal oxides. A preferred metallic-look pigment particle is aluminum flake.

Suitable metal or metal oxide-coated pigment particles are, for example, glass flakes coated with silver, titanium dioxide or iron oxide. For an example of metal-coated glass platelets and methods for making them see U.S. Patent No. 5,753,371, which is hereby incorporated by reference in its entirety. Goniochromatic lustrous pigments comprise multicoated platelet-shaped metallic substrates, transparent non-metallic substrates or multicoated metal-oxide platelets. Aluminum platelets are employed as metallic substrate, mica is employed as transparent non-metallic substrate and iron oxide is employed as metal-oxide platelets. These lustrous pigments are described in greater detail in EP 741 170, EP 708 154 and EP 753 545. They are available from a variety of suppliers including BASF under the trade names PALIOCHROM™ and VARIOCHROM™.

Examples of multilayered interference pigments having a light-opaque aluminum layer as the central layer are produced by the Flex Company under the trade names CHROMAFLAIR™ and OVP™ (optically variable pigments). These pigments, which are primarily employed in security printing, basically have a five-layered structure. On a central light-opaque aluminum layer, layers of magnesium fluoride as interlayers and subsequently semi-transparent chromium layers as outer layers are deposited on both sides. The pigments are described in U.S. Patent No. 4,434,010, which is hereby incorporated by reference in its entirety.

Interference pigments having transparent support materials are known as pearlescent pigments. The platelet-shaped transparent support materials may be mica, other phyllosilicates, such as talc or kaolin, glass flakes, silicon dioxide (SiO₂) flakes, titanium oxide (TiO₂) flakes or aluminum oxide (Al₂O₃) flakes. These support materials are coated with one or more metal-oxide layers. The metal oxides used here are both colorless high- refractive-index metal oxides, such as, for example, titanium dioxide or zirconium oxide, colorless low-refractive-index metal oxides, such as, for example, silicon dioxide or aluminum oxide, and colored metal oxides, such as, for example, chromium oxide, cobalt oxide and in particular iron oxides. These platelet-shaped pearlescent pigments are known and for the most part commercially available.

Liquid-crystal pigments are interference pigments based on liquid-crystalline polymers. The individual pigment particles are fragments of a thin cross-linked film of liquid-crystalline polymers. The color effects which can be achieved therewith are based on the regular structure and homogeneous arrangement of the molecules in the form of a liquid crystal and on interference, attributable thereto, of a certain spectral light fraction which is reflected by the pigment. The other light fractions pass through the pigment. Liquid- crystalline interference pigments are described in U.S. Patent No. 5,807,497 and U.S. Patent No. 5,824,733, which are hereby incorporated by reference in their entirety. They are available from Wacker-Chemie GmbH under the trade name HELICONE™HC.

Metallic-look pigment particles are three dimensional platelets having a longest dimension, or length (L), a second longest dimension, or width (W), and a thickness (T). However, because the thickness is small they are often referred to as two-dimensional. Platelet shapes are conveniently described by the two-dimensional term "aspect ratio", which is defined herein as the metallic-look pigment particle's length divided by its thickness (L/T). Preferably, the metallic-look pigment particles of the present invention have an aspect ratio equal to or greater than 1, more preferably equal to or greater than 2, and most preferably equal to or greater than 3. Preferably, the metallic-look pigment particles of the present invention have an aspect ratio equal to or less than 10,000, more preferably equal to or less than 1,000, more preferably equal to or less than 300, more preferably equal to or less than 150, and most preferably equal to or less than 75.

Preferably, the metallic-look pigment particles of the present invention have a mean L, as defined by the volumetric d50, equal to or less than 300 microns, more preferably equal to or less than 150 microns, and most preferably equal to or less than 75 microns. Preferably, the metallic-look pigment particles of the present invention have a mean L as defined by the volumetric d50, equal to or greater than 0.1 micron, more preferably equal to or greater than 1 micron, even more preferably equal to or greater than 5 microns and most preferably equal to or greater than 10 microns.

Metallic-look pigment particles have an outside surface. The outside surface is made up of a top surface (corresponding to a first area represented by the length multiplied by the width), an opposing bottom surface (corresponding to a second area represented by the length multiplied by the width), separated by a thin side surface (corresponding to the thickness of the platelet). Depending on the shape of the platelet, the side surface may comprise one or more surfaces. For example, if the platelet is rectangular, its side surface is made up of a first, second, third, and fourth side surface. The top or bottom surface of the platelet may have any probable shape (for example, circular, square, rectangular, other polygons or random) and can include any topological feature or surface curvature which is inherent in the manufacture of the platelets, for example shapes referred to as silver dollar shape, corn flake shape, and potato chip shape.

The exterior surface of the metallic-look pigment particle may be coated with a functionalizing compound. The encapsulated metallic-look pigment of the present invention may comprise uncoated metallic-look pigment particles, metallic-look pigment particles coated with a functionalizing compound, or mixtures thereof. The purpose of the functionalizing compound is to help promote compatibility between the metallic-look pigment particle and the encapsulating material. The functionalizing compound can render the surface of the metallic-look pigment particle hydrophilic, hydrophobic, organophilic, or may possess one or more reactive group that can chemically (ionically and/or covalently) bond with either or both the metallic-look pigment particle and/or the encapsulating material. The functionalizing compound may also alter the surface properties of the metallic pigment to allow the deposition of organic or inorganic encapsulating media via crystallization processes. Examples of functionalizing compounds are oils, such as mineral oils and silicone oils, titanium coupling agents, aluminum coupling agents, aluminum chelating agents, and silicon-organic compounds.

A particularly suitable functionalizing compound is a silicon-organic compound such as those disclosed in U.S. Patent No. 5,332,767, which is incorporated herein by reference in its entirety. In particular, a silicon-organic compound which can be reacted to provide a siloxane and preferably contains at least one organic reactive group. Examples of such organic reactive groups are amino groups, epoxy groups, acryl groups, methacryl groups, vinyl groups, diene groups, mercapto groups, urethane groups, and isocyanurate groups. Preferred functionalizing compounds are silicon-organic compound comprising an acryl-, methacryl-, or vinyl-reactive group. These reactive groups can form chemical bonds to the encapsulating material.

Specific silicon-organic compounds, which contain organic reactive groups and are suitable for the present invention, but without limitation thereto are: 3 -aminopropyl- trimethoxysilane, N-methyl- 3 -aminopropyltrimethoxysilane, 3-aminopropyl- triethoxysilane, 3-aminopropyl-tris (2-methoxy-epoxy-ethoxy-silane), N-aminoethyl- 3- aminopropyltrimethoxysilane, 3-acryloxypropyl-trimethoxysilane, 3 -glycidyloxypropyl- trimethoxysilane, 3-mercaptopropyl-trimethoxysilane, 3-mercaptopropyl- triethoxysilane, beta-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, tris(3-trimethoxysilylpropyl) isocyanurate, 3 -mercaptopropyl-methyldimethoxysilane, vinyltrichlorsilane, vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl -tris (2- methoxyethoxy) silane, 7-octenyltrimethoxysilane, and 3-

(cyclopentadienylpropyl)triethoxysilane or its dimer. A preferable silicon-organic compound is 3-methacryloxypropyl-trimethoxysilane sometimes referred to as 3- (trimethoxysilyl) propyl methacrylate (3-TMSPM). The herein preceding silanes may be used alone or in combination. Preferably, the amount of silicone-organic compound used for coating the metallic-look pigment particle is at least such that a monomolecular layer can be formed on the platelet or flake. In another embodiment of the present invention, suitable silicon-organic functionalizing compounds do not contain organic reactive groups which bond to the encapsulating material as described hereinabove. Instead, these compounds derive their compatibilizing activity from physio-chemical interactions between chemical moieties attached to the silicon-organic compound and the encapsulating material. In addition to siloxane forming groups as above, such compounds would also typically contain relatively unreactive aliphatic and aromatic hydrocarbon groups, including chemical moieties such as alkyl groups, substituted alkyl groups, cyclo-alkyl groups, aromatic groups, aryl groups, etc. Specific examples of such silicon-organic compounds which are suitable for the present invention, but without limitation thereto are: tetraethoxysilane, n-octyl-triethoxysilane, iso- octyl-trimethoxysilane, propyl-trimethoxysilane, dimethyl-dimethoxysilane, methyl- triethoxysilane, cyclohexyl-trimethoxysilane, phenyl-trimethoxysilane, diphenyl- dichlorosilane, and phenethyl-trimethoxysilane. Also included as part of this invention are functionalizing compounds comprising mixtures of silicon-organic compounds without reactive groups and functionalizing compounds with groups capable of reacting with the encapsulating material as described above.

In order to make high aspect ratio materials such as flakes having a hydrophilic surface compatible with organic monomers, such materials may need to be treated with a functionalizing compound, such as, for example, oleic acid. Unencapsulated high aspect ratio materials can be divided into two categories with respect to their behavior in organic media: organic compatible and organic non-compatible. The material's behavior may be tested by preparing a biphasic mixture such as toluene/water, and then adding the material into that mixture. If the material stays in the organic portion of the mixture, the material is organic compatible (that is, hydrophobic or organo-philic). If the material prefers the aqueous layer of the mixture, the material is organic non-compatible (that is, hydrophilic). The test is indicative of the material's preference for one of these two phases: hydrophobic or hydrophilic. For higher encapsulation efficiency, it is desirable to have organic compatible (that is, hydrophobic) materials. Therefore, in cases where materials are found non-compatible, surface treatment/modifications may be carried out to render such materials organic compatible.

In an another embodiment, suitable functionalizing compounds are molecules comprising a long alkyl chain and a polar end group such as, for example, thiols, sulfonic acids, phosphonic acids, carboxylic acids, carboxylates, amines, and/or quaternary ammonium salts. The functionalizing compounds may be polymeric, and may comprise, for example, sulfonated polystyrene, polystyrene bearing amino groups and sulfonated EPDM. The nature of the polar end group will depend on the nature of the surface. Depending on the substrate, a convenient end group may be chosen to achieve an interaction that can be ionic, covalent or non-covalent in nature. The functionalizing compounds can also contain, besides the end group and hydrophobic portion, other reactive groups. Such reactive groups can be used to carry out further reactions. This procedure to render such materials organic compatible can also be used when the functionalizing compound is wet or contains organic components that can be removed by known procedures such as, for example, simple or azeotropic distillation.

Numerous metallic-look pigment particles are commercially available, such as, for example, aluminum flakes which are contained in a carrier agent, such as mineral oil. In various embodiments the flakes may be used as received, or the carrier agent may be removed by washing the flakes in a suitable solvent. In either case, the flakes may be added directly to the suspension of reactants in water, or the flakes may first be suspended in the monomer(s), for example by sonication, at room temperature, and then be added to an aqueous solution comprising a suspension agent.

Any method which can provide encapsulation of a metallic-look pigment particle with an encapsulating material to produce an encapsulated metallic-look pigment is within the scope of the present invention. As used herein, the term "encapsulate" means to surround partially or wholly. An encapsulated metallic-look pigment particle is distinct from, and different from a metallic-look pigment particle which has material applied to its top surface, its bottom surface or both its top and bottom surface, such structures comprise layers of material and are not encapsulated, for example, surrounded partially or wholly, by encapsulating material. Examples of encapsulating processes are, but not limited to, polymerization, melt mixing, spray drying, crystallization, and glass bead manufacturing. In one embodiment, the process for encapsulating metallic pigments of the present invention involves a series of steps: In the first step, the metallic pigment is mixed with a glass, a preformed polymer, or a preformed polymer precursor, while in the liquid state, so that it is evenly distributed within the encapsulating material or its precursor. The preformed polymer precursor may be a monomer, combination of monomers, or a partially polymerized, oligomeric material commonly known as a "B-stage" resin. For a glass, heat must applied to melt this material and thereby obtain it in a liquid state. For preformed polymers or polymer precursors, if these materials are not in a liquid state under normal conditions, they may be heated or dissolved in a suitable solvent to form a liquid. In the second step, this mixture or suspension of metallic pigment with liquid encapsulating material or its precursor is then subdivided into discrete composite particles by an appropriate size diminution process. This subdivision process may entail the dispersion of the suspension containing metallic pigment in liquid encapsulating material or precursor in a separate gas or liquid phase, in which it is immiscible. In the final step, the subdivided mixture of metallic pigment with liquid encapsulating material or precursor is solidified by a variety of processes to complete the formation of the encapsulated metallic pigment. When the encapsulating medium is a glass or a preformed polymer melt, this solidification step involves cooling the molten droplets containing metallic pigment while preventing contact between adjacent droplets to avoid agglomeration. When the encapsulating liquid is a monomer or oligomer polymer precursor, solidification is carried out by an appropriate polymerization process. When the encapsulating liquid is a solution of a preformed polymer in a solvent, the solidification process involves solvent removal via a polymer devolatilization process.

Suitable encapsulating material 3 for the present invention can be glass, an inorganic crystal, plastic, or combinations thereof. Preferably, the encapsulating material is transparent. As used herein, the term "transparent" includes translucent or semitransparent materials having a light transmittance of between 10 and 50 percent and transparent materials having a light transmittance of greater than 50 percent, wherein light transmittance is measured according to ASTM D 1003. The encapsulating material can be colorless or colored, for example with dyes, depending on the desired appearance of the article comprising the encapsulated metallic-look pigment. Preferably the encapsulating material is colorless and transparent.

The encapsulating material may further comprise various additives commonly used in such compositions such as other pigments or dyes, optical brighteners, antioxidants, acid scavengers, ultraviolet (UV) stabilizers, heat stabilizers, neutralizers, antiblock agents, antistat agents, clarifϊers, waxes, flame retardants, processing aids, extrusions aids, fillers, compatibilizers, or combinations thereof. Effective amounts are known in the art and depend of the particular additive and its desired effect.

Plastic is a preferred encapsulating material. It may be desirable to cross-link the plastic encapsulating material. Cross-linking can improve the properties of plastic, for example such as solvent resistance; impact resistance; heat resistance such as increase softening or melting point; increase melt elasticity; improve encapsulated metallic-look pigment shape retention under shear and/or heat conditions, that is, such as those experiences in melt blending, and injection molding or extrusion. The plastic encapsulating material is preferably a thermoset plastic, a thermoplastic, or combinations thereof.

Thermoset plastic polymers suitable for the present invention include, but are not limited to, unsaturated polyester resins, phenolic resins, epoxy resins, and silicone resins.

Thermoplastic polymers suitable for the encapsulating material of the present invention include, but are not limited to, polycarbonates (PC), copolyester carbonates, polymethyl methacrylate (PMMA), polyetherimides, transparent polyimides, polyethylene (PE), polypropylene (PP), olefin copolymers, halogenated olefin polymers and copolymers, transparent polyamides (nylons), polyesters, transparent polycarbonate-polyester blends, polysulfones, polyether and polyphenyl sulfones, transparent acrylonitrile butadiene styrene (TABS), styrene acrylonitrile (SAN), polystyrene (PS), transparent impact modified polystyrene (TIPS), cellulosics, miscible transparent polystyrene-polyphenylene oxide (PS- PPO) blends, acrylics, polycarbonate-polysiloxanes, polyetherimide-polysiloxanes, polyarylates, polyethylene terephthalate, thermoplastic polyurethane (TPU) and blends and copolymers of all of the above. Preferred transparent thermoplastic encapsulating materials are polyetherimides, polymethyl methacrylate, polycarbonate (homopolymer or copolymers), copolyester carbonates, polyethylene terephthalate (PET), styrene acrylonitrile, polystyrene, transparent acrylonitrile butadiene styrene and cellulosics. Another suitable encapsulating material is a synthetic elastomer such as styrene and butadiene rubber (SBR), hydrogenated styrene butadiene styrene block copolymers (SEBS), ethylene, propylene and diene monomer (EPDM), polyethylene (PE), polypropylene (PP) and mixtures thereof. More preferred encapsulating materials are polystyrene, polymethyl methacrylate, and a clear aromatic polycarbonate homopolymer based primarily on the bisphenol-A monomer. Thermoplastic polymers are prepared by the polymerization of monomers. Any polymerization process which allows for polymerization of an encapsulating thermoplastic material in the presence of a metallic-look pigment particle to produce an encapsulated metallic-look pigment is suitable for the present invention. Various processes for making these thermoplastic polymers are well known in the art. For example, the polymerization process may be a solution polymerization process, a mass polymerization process, an emulsion polymerization process or preferably a suspension polymerization process.

Generally, suspension polymerization is a batch-mode process, but a continuous process is also suitable. In a typical suspension polymerization process, a metallic-look pigment particle is first dispersed in an organic medium containing one or more monomers, which can be polymerized via free radical based or other polymerization processes. Preferably, the conventional metallic-look pigment particles are first treated with a functionalizing compound, which improves their compatibility with the organic monomer(s). A pigment/organic monomer slurry results. This pigment/organic monomer slurry is then added to an aqueous system containing one or more suspension stabilizing agents, which help to reduce interfacial tension between the two liquid phases. A two phase hydrophilic/hydrophobic liquid mixture results. Preferably, the pigment/organic monomer slurry comprises less than 60 volume percent of the two phase hydrophilic/hydrophobic liquid mixture. The functionalizing compound applied to the metallic-look pigment particles enhances the partitioning of the pigment into the organic phase in the two phase liquid mixture.

Suitable suspension stabilizing agents migrate to the interface between organic phase and aqueous phase, forming a protective film which hinders agglomeration of the polymerizing organic phase particles containing the metallic pigment. In one embodiment, the suspension stabilizing agents are inorganic compounds, which are slightly soluble in water, for example phosphates (for example, calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, etc.); pyrophosphates (for example, calcium pyrophosphate, magnesium pyrophosphate, aluminum pyrophosphate, zinc pyrophosphate, etc.); hydroxides (for example, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, ferric hydroxide, etc.); carbonates (for example, calcium carbonate, barium carbonate, magnesium carbonate, etc.); sulfates (for example, barium sulfate, calcium sulfate, etc.); along with other inorganic compounds such as colloidal silica, calcium metasilicate, and calcium oxalate. Silica and calcium phosphate are preferred inorganic compounds.

In another embodiment, the suspension stabilizing agents are macromolecular compounds having an affinity towards the monomer. These polymeric agents typically contain a hydroxyl group, an amido group, a carboxyl group, a sulfo group or a phosphono group, or an alkali metal or ammonium salt of a carboxyl, sulfo or phosphono group. Some examples are water-soluble cellulose ethers such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose, and the sodium salt of carboxymethyl cellulose; water-soluble partially saponified polyvinyl alcohols, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, polyethylene-imine, polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerol oleate gelatin, starch, sodium oligostyrenesulfonate, acrylic acid polymers, and sodium salts of polymers of acrylic or methacrylic acid or of copolymers of acrylic or methacrylic acid with an alkyl acrylate or an alkyl methacrylate. Other examples are oil-soluble emulsifiers such as sorbitan monolaurate, sorbitan triolate, glycerol tristearate and an ethylene oxide/propylene oxide block copolymer.

The inorganic suspension stabilizing agents and macromolecular compounds suspension stabilizing agents may be used either alone or in any combination. Typically they are used at a loading of 0.05 to 20 percent based on the weight of the monomer. In addition to these stabilizing agents, other compounds such as surfactants and soaps (for example, sodium lauryl sulfate, sodium dodecyl benzenesulfonate, etc.) may also be used to modify the activity of the primary or secondary suspending agents, toward the ultimate goal of stably producing the encapsulated metallic pigment particles of this invention.

The two phase hydrophilic/hydrophobic liquid mixture is agitated to break up the pigment/monomer slurry into small droplets. Agitation can be achieved by a mixer mounted internally in the reaction vessel, or the mixture may be sized by a device external to the reaction vessel either during the reactor filling operation or by pumping a portion of the reactor contents through a sizing apparatus (for example, a static mixer assembly or a high speed disperser such as a rotor-stator mixer) and returning it to the reactor. Polymerization is initiated within the pigment/monomer slurry droplets by increasing the temperature of the system to a level where autopolymerization begins in the monomer, or more preferably, to a temperature where an organic soluble, free radical initiator (for example, a soluble peroxide, an azo-containing compound, and the like), which has been added to the monomer mixture, begins decomposing to generate free radicals, initiating polymerization of the monomer.

A lipophilic peroxide or an azo-type initiator which is commonly used in the suspension polymerization can be used as the polymerization initiator. Particularly, peroxide-type polymerization initiator such as benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxy dicarbonte, t-butyl peroxy-2-ethylhexanoate (t-butyl peroctoate), t-butyl peroxybenzoate, l,l-di-t-butylperoxy-2-methylcyclohexane, cumene hydroperoxide, cyclohexanone peroxide, tert-butyl hydroperoxide, diispropylbenzene hydroperoxide, etc., and azo-type initiators, such as 2,2'-azobisisobutyronitrile, 2,2'- azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,3-dimethylbutyronitrile), 2,2'-azobis(2- methylbutyronitrile), 2,2'-azobis(2,3,3-trimethylbutyronitrile), 2,2'-azobis (2- isopropylbutyronitrile), 1 , 1 '-azobis(cyclohexane 1 -carbonitrile), 2,2'-azobis(4-methoxy-2,4- dimethlvaleronitrile), 2-(carbamoylazo)isobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), dimethyl-2,2'-azobisisobutyrate, may be exemplified. In general, the initiator is used in an amount of preferably from 0.01 to 3 parts by weight per 100 parts by weight of the total amount of all monomer introduced.

Preferably, the organic monomer phase, which contains the metallic-look pigment particles, also contains one or more bi- or multifunctional species which cause the polymerizing droplets to gel or crosslink into a network structure. Among other things, the cross-linking of the polymeric encapsulating material of the, encapsulated metallic-look pigment helps to inhibit dissolution of the encapsulating material in the presence of conventional solvents. Additionally, cross-linking helps to lock in the structure formed during polymerization, potentially inhibiting agglomeration, break up, or substantial deformation of the encapsulate metallic-look pigment in its end product application, such as flow fields normally encountered in subsequent polymer melt processing techniques such as extrusion or injection molding. Preferred crosslinking agents include divinyl benzene and ethylene glycol dimethacrylate.

After polymerization, the encapsulated metallic-look pigment is isolated as a free flowing powder by centrifuging or filtering the reaction mixture producing a wet cake, washing the wet cake with water (to remove latex polymer, and water soluble suspending agents), and drying the retained solids. The encapsulated metallic-look pigment of the present invention is isometric in shape. As used herein, the term "isometric" means that the shape is three dimensional and has dimensions X, Y, and Z (d50) in three spatial directions, in one embodiment, the dimensions of X, Y, and Z are all within +/- 25 percent of each other. In other words the dimension for X is +/- 25 percent of the values for Y and Z and dimension for Y is +/- 25 percent of the values for X and Z and dimension for Z is +/- 25 percent of the values for Y and X. Preferably, the dimensions of X, Y, and Z are all within +/- 20 percent of each other, more preferably the dimensions of X, Y, and Z are all within +/- 15 percent of each other, and even more preferably the dimensions of X, Y, and Z are all within +/- 10 percent of each other, and most preferably the dimensions of X, Y, and Z are all within +/- 5 percent of each other.

In another embodiment, the aspect ratio of the encapsulated metallic-look pigment, is equal to or greater than 1, preferably equal to or greater than 1.25, more preferably equal to or greater than 1.5, even more preferably equal to or greater than 1.75, and most preferably equal to or greater than 2. The aspect ratio of the encapsulated metallic-look pigment, is equal to or less than 5, preferably equal to or less than 4, more preferably equal to or less than 3, even more preferably equal to or less than 2.5, and most preferably equal to or less than 2.25. When referring to the aspect ratio of the encapsulated metallic-look pigment, it is defined as the longest demission (of X, Y, and Z) divided by the shortest dimension (of X, Y, and Z).

Preferably the isometric shape is a polyhedron, more preferably it is a cube, and most preferably it is a sphere.

The encapsulated metallic-look pigment of the present invention has a minimum dimension (d50) of equal to or greater than 1 micron, preferably a minimum dimension of equal to or greater than 5 microns, more preferably a minimum dimension of equal to or greater than 10 microns, even more preferably a minimum dimension of equal to or greater than 15 microns, and most preferably a minimum dimension of equal to or greater than 20 microns. The encapsulated metallic-look pigment of the present invention has a maximum dimension (d50) of equal to or less than 1,000 microns, preferably a maximum dimension of equal to or less than 500 microns, more preferably a maximum dimension of equal to or less than 300 microns, even more preferably a maximum dimension of equal to or less than 200 microns, even more preferably a maximum dimension of equal to or less than 150 microns and most preferably a maximum dimension of equal to or less than 75 microns. The metallic-look pigment particle may be completely encapsulated 1 or partially encapsulated 4 by the encapsulating material. If the metallic-look pigment particle is partially encapsulated, the encapsulating material surrounds at least 40 percent of the metallic-look pigment particle, more preferably it surrounds at least 50 percent of the metallic-look pigment particle, even more preferably it surrounds at least 65 percent of the metallic-look pigment particle, even more preferably it surrounds at least 80 percent of the metallic-look pigment particle, even more preferably it surrounds at least 90 percent of the metallic-look pigment particle, even more preferably it surrounds at least 95 percent of the metallic-look pigment particle, and most preferably it surrounds 100 percent of the metallic- look pigment particle.

The encapsulated metallic-look pigment of the present invention can comprise more than one metallic-look pigment particle. For example, it may comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more metallic-look pigment particles. If the metallic-look pigment comprises more than 1 metallic-look pigment particle, the spatial orientation between the multiple metallic-look pigment particles is not critical, in other words the spatial arrangement may be parallel, perpendicular, end-to-end, side-to-side, random, or, depending on the numbers of metallic-look pigment particles in the encapsulated metallic- look pigments, combinations thereof, Figure 2.

If the encapsulated metallic-look pigment of the present invention comprises more than one metallic-look pigment particle, the metallic-look pigment particles may be the same or different. In other words, there can be one or more metal pigment, one or more metal oxide-coated glass platelet pigment, one or more goniochromatic lustrous pigment, one or more interference pigment, one or more pearlescent pigment, one or more liquid- crystal pigment and/or combinations thereof. The length distribution for the metallic-look pigment particle(s) of the present invention may be monomodal or multimodal.

The metallic-look pigment particle is typically present in the encapsulated metallic- look pigment in an amount equal to or greater than 0.01 part by weight based on the weight of the encapsulated metallic-look pigment, preferably in an amount equal to or greater than 0.1 parts by weight, more preferably in an amount equal to or greater than 0.5 parts by weight, even more preferably in an amount equal to or greater than 0.75 parts by weight, and most preferably in an amount equal to or greater than 1 part by weight based on the weight of the encapsulated metallic-look pigment. The metallic-look pigment particle is typically present in the encapsulated metallic-look pigment in an amount equal to or less than 99 parts by weight based on the weight of the encapsulated metallic-look pigment, preferably in an amount equal to or less than 90 parts by weight, more preferably in an amount equal to or less than 80 parts by weight, even more preferably in an amount equal to or less than 50 parts by weight, even more preferably in an amount equal to or less than 25 parts by weight, even more preferably in an amount equal to or less than 15 parts by weight, even more preferably in an amount equal to or less than 10 parts by weight, even more preferably in an amount equal to or less than 8 parts by weight and most preferably in an amount equal to or less than 6 parts by weight based on the weight of the encapsulated metallic-look pigment. The encapsulated metallic-look pigment of the present invention can be incorporated into any medium requiring a metallic-look appearance, including, but not limited to, thermoplastics, thermoset plastics, paints, inks, toners, cosmetics, glues, and pastes. One or more encapsulated metallic-look pigment can be incorporated into the medium requiring a metallic-look appearance. A particularly desirable application of the encapsulated metallic-look pigments of the present invention is for use in fabricated plastic articles requiring a metallic-look, especially thermoplastic articles prepared by blow molding, extrusion, thermoforming or injection molding and in particular articles which require improved weld or knit line appearance. The encapsulated metallic-look pigment can be used with any thermoplastic. Examples of suitable thermoplastics include, but are not limited to: polycarbonates (PC), copolyester carbonates, polymethyl methacrylate (PMMA), polyetherimides, polyimides, halo olefin polymers, polyamides, polyesters, polysulfones, polyether and polyphenyl sulfones, acrylonitrile butadiene styrene terpolymers (ABS), styrene acrylonitrile copolymers (SAN), polystyrenes (PS), cellulosics, polyphenylene oxides or sometimes referred to as polyphenylene ethers (PPO or PPE), acrylics, polysiloxanes, polyarylates, thermoplastic polyurethanes (TPU), polyethylenes (PE), polypropylenes (PP), and blends thereof, especially PC-ABS, PS-PPO, PS-PPE, PC-polysilioxane, polyetherimide- polysiloxanes. Preferred polyesters are polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); preferred polyethylenes are linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), ultra high density polyethylene (UHDPE), metallocene catalyzed polyethylenes such as linear ethylene polymers (LEP) and substantially linear ethylene polymers (SLEP); preferred polypropylenes are homopolymer polypropylenes, copolymer polypropylenes, elastomer modified polypropylenes or thermoplastic polyolefins (TPO), metallocene catalyzed polypropylene; and preferred polystyrenes are general purpose polystyrene (GPS), syndiotatic polystyrene (sPS), transparent impact modified polystyrene (TIPS), and high impact polystyrene (HIPS). When blended with a thermoplastic, the refractive index (RI) of the encapsulating material of the encapsulated metallic-look pigment can be identical, similar or different from that of the thermoplastic.

The encapsulated metallic-look pigment is used in thermoplastic and/or thermoset plastic compositions in an amount of equal to or greater than 0.1 part by weight based on the weight of the total plastic composition, preferably equal to or greater than 0.5 part by weight, more preferably equal to or greater than 1 part by weight, even more preferably equal to or greater than 2 parts by weight, even more preferably equal to or greater than 5 parts by weight, and most preferably equal to or greater than 10 parts by weight based on the weight of the total plastic composition. The encapsulated metallic-look pigment is used in thermoplastic and/or thermoset plastic compositions in an amount of equal to or less than 99 parts by weight based on the weight of the total plastic composition, preferably equal to or less than 90 parts by weight, more preferably equal to or less than 80 parts by weight, even more preferably equal to or less than 40 parts by weight, even more preferably equal to or less than 25 parts by weight, and most preferably equal to or less than 20 parts by weight based on the weight of the total plastic composition.

Thermoplastic and/or thermoset plastic compositions comprising encapsulated metallic-look pigments of the present invention may further comprise various additives commonly used in plastic compositions such as other pigments or dyes, optical brighteners, antioxidants, acid scavengers, ultraviolet stabilizers, heat stabilzers, neutralizers, antiblock agents, antistat agents, clarifiers, waxes, flame retardants, processing aids, extrusions aids, fillers, compatibilizers, and other additives within the skill in the art used in combination or alone. Effective amounts are known in the art and depend of the particular additive and its desired effect.

A thermoplastic composition comprising the encapsulated metallic-look pigment of the present invention can be produced by any well known polymer mixing technique, such as dry blending and subsequently melt mixing. Melt mixing can be achieved in an extruder (for example, a Banbury mixer, a single screw extruder, a twin screw extruder, etc.) and the extrudate is comminuted to pellets for a subsequent fabrication process to form a fabricated article. Alternatively, melt mixing can take place in the extruder that forms the fabricated article, for example in an injection molding machine, an extruder that produces a formed profile or sheet, or a blow molding machine.

Thermoplastic polymer compositions comprising an encapsulated metallic-look pigment of the present invention are softened by the application of heat and can be formed or molded using conventional techniques such as injection molding, blow molding, extrusion, thermoforming, or combinations thereof.

Injection molding processes are well known in the art and commercially practiced for production of a broad range of molded parts. As is known, injection molding processes typically include the steps of extruding or plasticating the resin under shearing and/or heating to provide a flowable resin, injection of the heat plastified flowable resin into the mold through a runner, applying additional pressure to pack the resin into the mold and cooling the molded parts to solidify the part enough to remove from the mold.

Alternatively, the thermoplastic composition comprising the encapsulated metallic- look pigment of the present invention can be extruded into sheet. The sheet may be a mono-layer sheet or a multi-layer sheet where the thermoplastic comprising the encapsulated metallic-look pigment comprises one or more of the layers, for example it can be the top layer, the bottom layer, an internal layer, or combinations thereof in a multi-layer sheet. A mono-layer or multi-layer sheet comprising a thermoplastic composition comprising the encapsulated metallic-look pigment of the present invention can be thermoformed into a fabricated article through the use of conventional machinery employing conventional conditions. There are a number of thermoforming techniques in use, but all are basically variations of two simple processes in which a heated sheet is moved by (1) air in the form of an applied vacuum and/or pressurized air, or (2) mechanical draw assists which force the sheet into a mold to produce the desired contoured or shaped article. In many cases the two processes are combined to result in a wide variety of procedures to make thermoformed articles. For example, thermoforming methods include, but are not limited to, straight forming, drape forming, snapback forming, reverse-draw forming, plug-assist forming, plug-assist/reverse draw forming, air-slip forming/plug-assist, air-slip forming, matched tool forming, and twin-sheet forming.

The thermoforming process includes heating a sheet until it softens or starts to sag, after which one or more of vacuum, air pressure, and/or mechanical draw assist is applied and the heated sheet is drawn into a female mold, sometimes referred to as die, drawn over a male mold, or the two molds are used together to form an article, the formed article is cooled, removed from the mold, and trimmed as necessary.

Thermoplastic compositions comprising an encapsulated metallic-look pigment of the present invention or thermoset plastic compositions comprising an encapsulated metallic-look pigment of the present invention can be fabricated into any article capable of being formed from a thermoplastic or thermoset plastic. For example, including, but not limited to, the following: an automotive article, a lawn and garden article, a boat article, a snowmobile article, a personal water craft article, an enclosure for a computer, an enclosure for a computer accessory, an enclosure for a printer, an enclosure for a copier, an enclosure for a fax machine, an enclosure for a cell phone, an enclosure for a hand held personal data assistant, an enclosure for a television set, an enclosure for a audio system, a housing for a telephone, a housing for a small electrical appliance, a housing for an electrical tool, a washing machine cover, a dryer cover, a refrigerator cover, a freezer cover, a dish washer cover, a toy, a comb, a brush handle, a tooth brush handle, a cosmetic container, a ski boot, a sink, a toilet, a bath surround, a shower surround, or furniture.

EXAMPLES Example 1

A 300 ml glass Citrate bottle is loaded with 0.5 gram (g) aluminum flake paste in mineral oil (SILBERLINE™ SSP-760-20-C is 80 percent by weight aluminum flake in mineral oil) and 25.0 g styrene monomer containing 0.5 percent by weight t-butyl peroctoate. The bottle is swirled to distribute the metallic-look pigment particle in the organic monomer. 150 milliliter (ml) 0.25 percent by weight aqueous hydroxypropyl methylcellulose ether (METHOCEL™ K4M available from The Dow Chemical Company) solution is then added to the Citrate bottle. Nitrogen gas is then sparged into the liquid for about 5 minutes (min.) to replace the air in the headspace. The bottle is then sealed using crimp seal bottle cap fitted with a barrier film and shaken vigorously to mix the components in the bottle.

The Citrate bottle is then placed into a rotating basket mounted inside a temperature controlled water bath. The rotating basket provided agitation by turning the bottle end over end at a speed of approximately 30 revolutions per minute (rpm). The water bath is heated from its initial 20 °C to the polymerization temperature of 74 ⁰C over the course of one hour (hr.). The bath is then maintained at 74 ⁰C for 7 hr. then rapidly cooled back to 20 °C. The end over end rotation is continued throughout the polymerization step.

At the conclusion of polymerization step, the contents in the Citrate bottle consist of a mixed gray and white precipitate in a foamy, white aqueous phase. The precipitate is collected by filtration and washed well with water. The aqueous phase and rinses are discarded. The product is dried in a forced air convection oven at 60 ⁰C overnight to yield 20.43 g of a grayish- white powder. This powder is imbedded in epoxy, sectioned, polished, and characterized by optical microscopy. The product of the polymerization step comprised encapsulated metallic-look pigments containing multiple aluminum flakes as well as polymeric microspheres comprising no aluminum flakes. Example 2

Prior to encapsulating in a polymer matrix, aluminum flakes are functionalized with a silane according to the following procedure:

10.0 g aluminum flakes in mineral oil (SILBERLINE SSP-860-20-C) are weighed into a single necked 500 ml round bottom flask. 200 ml reagent grade toluene and a magnetic stir bar are added to the flask and the slurry is stirred on a magnetic stir plate for 15 min. The flask is then allowed to sit in a lab hood to allow the aluminum flakes to settle for about 2 hr. The clear supernatant liquid above the silvery precipitate is then removed by pipette and discarded. A further 200 ml toluene is added to the aluminum in the flask, stirred, and allowed to settle as above. The supernatant liquid is siphoned off as above and the precipitate is washed with 2 additional toluene washes using the same procedure.

After the fourth addition of 200 ml toluene, 0.30 g of deionized water is added to the slurry of aluminum flakes along with 2.0 g 3-(trimethoxysilyl) propyl methacrylate (3- TMSPM). The flask is fitted with a water cooled condenser and mounted in a water bath sitting atop a magnetic stir plate. With the stirrer rotating at medium speed, the water bath is heated from ambient temperature to 80 °C and maintained at that temperature for about 5 hr. The hot functionalized aluminum flake slurry is then poured into large crystallizing dish to cool and settle. After settling for about two hr., the clear supernatant liquid is siphoned off the precipitate using a pipette and the functionalized metallic-look pigment particles precipitate is allowed to dry in a lab hood overnight.

After drying overnight, the crystallizing dish is placed into a vacuum oven preheated to 120 °C and maintained at that temperature under a deep vacuum for about one hr. The crystallizing dish is removed from the oven and cooled to room temperature, the functionalized aluminum flake is scraped from the dish using a spatula and transferred to a tared vial, yielding 7.70 g of 3-TMSPM functionalized aluminum flakes. Example 3

Encapsulated metallic-look pigment is prepared from the 3-TMSPM functionalized aluminum flakes from Example 2 according to the following suspension polymerization procedure:

A monomer mixture for polymerizing cross-linked polystyrene beads is prepared, consisting of:

40.0 g styrene monomer 6.32 g divinylbenzene, 55 percent active component (DVB)

0.248 g t-butyl peroctoate (TBPO)

0.75 g of 3-TMSPM functionalized aluminum flakes are weighed into a single- necked 500 ml round bottom flask. 33.3 g of the above styrene/DVB/TBPO monomer mixture is then weighed into the same round bottom flask. A magnetic stir bar is added, and the flask is fitted with a water cooled condenser and mounted in a thermostatically controlled water bath sitting atop a magnetic stirrer. With the bath initially at room temperature, the stir bar is spun at medium speed for about 15 min. to disperse the functionalized aluminum flake in the monomer mixture. 200 ml 0.25 percent aqueous hydroxypropyl methyl cellulose ether (METHOCEL K4M) solution is then added to the flask through the condenser. The magnetic stirrer speed is increased to the maximum value, which produces a fine dispersion of gray droplets in the aqueous medium. The temperature controller for the water bath is then adjusted to a set point of 74 °C, which is achieved within about one hr. The water bath is maintained at 74 ⁰C for about 8 hr with vigorous magnetic stirring of the flask contents. Throughout the course of the polymerization, the reaction mixture remains a homogeneous, light gray colored suspension.

The polymerization product is recovered by pouring the reaction mixture into a beaker and allowing the grayish-silver colored precipitate to settle, drawing off the translucent aqueous phase, and washing the precipitate with several washes of water to remove emulsion polymer and suspending agent. The product is then dried by transferring the washed solids into glass dish and drying overnight at 60 °C in a forced air convection oven. When dried, the product consists of grayish-silver, free flowing beads. The total weight of product recovered is 26.05 g. A small portion of the recovered product is slurried in oil and examined under a microscope. The product comprises spherical beads, mostly in the range 200-500 microns. Almost all of the beads (80 percent or greater) contain dark, irregularly shaped inclusions of functionalized aluminum flakes. For beads containing pigment, the number of functionalized aluminum flakes per bead varied from 1 to 10. The aluminum flakes are located in the interior of the beads, bound to the outside surface of the beads, and combinations thereof. No free, unbound aluminum flakes are found in the sample. The encapsulated metallic-look pigment comprises an average of 2.2 weight percent aluminum flake and 97.8 weight percent cross-linked polystyrene encapsulating material. When illuminated from the side at various angles, the encapsulated functionalized aluminum flakes are found to be highly reflective. Example 4

Functionalized aluminum flake encapsulated in a cross-linked rubber is prepared from the 3 -TMSPM functionalized aluminum flakes of Example 2 hereinabove according to the following suspension polymerization procedure:

A monomer mixture for polymerizing cross-linked poly(butyl acrylate) beads is prepared, comprising:

76.8 g butyl acrylate monomer

3.2 g ethylene glycol dimethacrylate (EGDM) 0.40 g TBPO

1.50 g 3-TMSPM functionalized aluminum flakes are weighed into a single-necked 1000 ml round bottom flask. 66.6 g. of the butyl acrylate/EGDM/TBPO monomer mixture is weighed into the same round bottom flask. A magnetic stir bar is added, and the flask is fitted with a water cooled condenser and mounted in a thermostatically controlled water bath sitting atop a magnetic stirrer. With the bath initially at room temperature, the stir bar is spun at medium speed for about 15 min. to disperse the functionalized aluminum flakes in the monomer mixture. 400 ml. 0.25 percent aqueous hydroxypropyl methyl cellulose ether (METHOCEL K4M) solution is then added to the flask through the condenser. The magnetic stirrer speed is increased to the maximum value, which produces a fine dispersion of gray droplets in the aqueous medium. The temperature controller for the water bath is then adjusted to a set point of 74 ⁰C, which is achieved within about one hr. The water bath was maintained at 74 ⁰C for 8 hr. with vigorous magnetic stirring of the flask contents. Throughout the course of the polymerization, the reaction mixture remains a homogeneous, light gray colored suspension.

The product from the polymerization step is recovered by pouring the reaction mixture into a beaker and allowing the grayish-silver colored precipitate to settle, drawing off the dense white aqueous phase, and washing the precipitate with several washes of water to remove emulsion polymer and suspending agent. The product is then dried by transferring the washed solids into glass dish and drying overnight at 60 °C in a forced air convection oven. When dried, the product consists of rubbery, grayish-silver beads, which tend to clump together into loose aggregates. The total weight of product recovered is 61.2 g.

Example 5

Encapsulated metallic-look pigment is prepared from the 3-TMSPM functionalized aluminum flakes of Example 2 according to the following batch-mode suspension polymerization procedure: 2000 g 0.25 percent aqueous hydroxypropyl methyl cellulose ether (METHOCEL

K4M) solution is charged to a 1 gallon (4 liter) stainless steel autoclave reactor fitted with an upward pumping, turbine type agitator. The reactor is equipped with a jacket through which thermostatically controlled heat transfer fluid was circulated. A monomer mixture for polymerizing cross-linked polystyrene beads was prepared, comprising: 285.15 g styrene monomer

45.05 g DVB

1.765 g TBPO

7.5 g. 3-TMSPM functionalized aluminum flakes are weighed into a transfer container. Approximately half of the above styrene/DVB/TBPO monomer mixture is then poured into the transfer container containing the functionalized pigment, the container is swirled to distribute the pigment, and this slurry is transferred to the reactor while agitator is spinning at about 120 rpm. The remainder of the monomer mixture is poured into the transfer container, swirled, and transferred into the reactor to complete the addition of monomer and pigment into the reaction mixture. The headspace above the liquid in the reactor is inerted with nitrogen gas and the agitator speed is increased to 300 rpm. The temperature of the reactor is then increased from 20 ⁰C to 74 °C over the course of one hr., maintained at 74 °C for 7 hr., then rapidly cooled to 20 °C; stirring of the contents was continued until the product is removed. The reaction mixture is discharged from the reactor through a bottom mounted valve as a homogeneous gray liquid. Upon standing, this mixture is separated into a milky, white aqueous phase above a grayish-silver precipitate, which rapidly sinks to the bottom of the container. The aqueous phase is discarded and the precipitate is washed well with deionized water. The wet product is then dried overnight in a forced air convection oven at 60 °C to give a gray, free flowing powder which sparkles when illuminated. The total quantity of product recovered is 241 g. Characterization by optical microscopy showed the polymerization product to comprise round beads containing encapsulated functionalized aluminum pigment. Characterization of the mean particle size using a Beckman Coulter Counter yielded a volume median particle diameter of 198 microns. Example 6

Aluminum pigment flakes are functionalized with a fully hydrolyzed silane using a variation of the procedure disclosed in Example 2:

Hydrolyzed silane is prepared as follows: 0.5 g. glacial acetic acid and 2.5 g deionized water are weighed into a 50 ml glass jar and mixed using a magnetic stir bar.

10.0 g 3 -TMSPM is then added using a syringe, and stirring is continued. While initially a two phase mixture, after stirring for about an hr., the two phases come together to form a light yellow, clear solution of hydrolyzed silane with a noticeably higher viscosity.

30.0 g of aluminum flakes in mineral oil (SILBERLINE SSP-860-20-C) are weighed into a single necked 1000 ml round bottom flask. 400 ml. reagent grade isopropanol and a magnetic stir bar are added to the flask and the slurry is stirred on a magnetic stir plate for 15 min. The flask is then allowed to sit in a lab hood to allow the aluminum flakes to settle for about two hr. The clear supernatant liquid above the silvery precipitate is then removed by pipette and discarded. A further 400 ml isopropanol is added to the aluminum flakes in the flask, stirred, and allowed to settle as above. The supernatant liquid is siphoned off as above and the precipitate is washed with two further isopropanol washes using the same procedure.

After the fourth addition of 400 ml isopropanol, 5.0 g of the hydrolyzed silane is added and the mixture is allowed to stir overnight at room temperature. In the morning, the aluminum slurry is then poured into large crystallizing dish; the flask is washed with additional isopropanol, which is also added to the crystallizing dish. The dish is placed in a lab hood for several hours to allow the aluminum to settle. The clear supernatant liquid is then siphoned off and discarded. The silane treated aluminum flakes in the dish are allowed to dry overnight. In the morning, the crystallizing dish is placed into a vacuum oven preheated to 120 °C and maintained at that temperature under vacuum for about one hr. After removing the crystallizing dish from the oven and cooling to room temperature, the treated aluminum is scraped from the dish using a spatula and transferred to a tared vial, yielding 22.7 g of 3-TMSPM functionalized aluminum flakes. Example 7

Encapsulated metallic-look pigment containing a soluble blue dye is prepared from the 3-TMSPM functionalized aluminum flakes synthesized in Example 6 according to the following batch-mode suspension polymerization procedure: 2000 g of 0.25 percent aqueous hydroxypropyl methyl cellulose ether (METHOCEL

E50) solution is charged to a 1 gallon (4 liter) stainless steel autoclave reactor fitted with an upward pumping, turbine type agitator. 6.84 g of aqueous sodium dichromate (65 percent by weight) solution is added to the aqueous load to inhibit emulsion polymer formation. The reactor is equipped with a jacket through which thermostatically controlled heat transfer fluid is circulated. A monomer mixture for polymerizing cross-linked polystyrene beads was prepared, comprising:

285.15 g styrene monomer 45.05 g DVB

1.765 g TBPO 0.375 g Bayer MACROLEX™ Blue RR soluble dye

7.5 g 3-TMSPM functionalized aluminum flakes are weighed into a transfer container. Approximately half of the above styrene/DVB/TBPO monomer mixture is then poured into the transfer container containing the functionalized pigment, the container is swirled to distribute the pigment, and this slurry was transferred to the reactor while agitator was spinning at 120 rpm. The remainder of the monomer mixture is poured into the transfer container, swirled, and transferred into the reactor to complete the addition of monomer and pigment into the reaction mixture. The headspace above the liquid in the reactor is inerted with nitrogen gas and the agitator speed is increased to 300 rpm. The temperature of the reactor is then increased from 20 °C to 74 °C over the course of about one hr., maintained at 74 °C for about 7 hr., then rapidly cooled to 20 °C; stirring of the contents is continued until the product is removed.

The reaction mixture is discharged from the reactor through a bottom mounted valve as a homogeneous bluish liquid. Upon standing, this mixture separates into a cloudy, green aqueous phase above a bluish-silver precipitate, which rapidly sinks to the bottom of the container. The aqueous phase is discarded and the precipitate is washed well with deionized water. The wet product is then dried overnight in a forced air convection oven at 60 °C to give a bluish-gray, free flowing powder which sparkles when illuminated. The total quantity of product recovered is 294.6 g. Characterization by optical microscopy shows the encapsulated metallic-look pigment comprises functionalized aluminum flakes in nearly round beads with a homogeneous blue coloration. Characterization of the mean particle size of the encapsulated metallic-look pigment using a Beckman Coulter Counter yields a volume median particle diameter of 128 microns. Example 8

Aluminum flakes are functionalized using the same hydrolyzed silane procedure of Example 6 with the exception that the silane used is phenethyl, trimethoxysilane, which does not contain a reactive vinyl group. Hydrolyzed silane is prepared as follows:

0.5 g. glacial acetic acid and 2.5 g. deionized water are weighed into a 50 ml glass jar and mixed using a magnetic stir bar. 10.0 g phenethyl, trimethoxysilane is then added using a syringe, and stirring is continued. While initially a two phase mixture, after stirring for about an hour, the two phases come together to form a clear solution of hydrolyzed silane with a noticeably higher viscosity.

30.0 g of aluminum flakes in mineral oil (SILBERLINE SSP-860-20-C) are weighed into a single necked 1000 ml round bottom flask. 400 ml reagent grade isopropanol and a magnetic stir bar are added to the flask and the slurry is stirred on a magnetic stir plate for about 15 min. The flask is then allowed to sit in a lab hood to allow the aluminum flakes to settle for about two hr. The clear supernatant liquid above the silvery precipitate is then removed by pipette and discarded. A further 400 ml isopropanol is added to the aluminum in the flask, stirred, and allowed to settle as above. The supernatant liquid is siphoned off as above and the precipitate is washed with two further isopropanol washes using the same procedure.

After the fourth addition of 400 ml isopropanol, 5.0 g of the hydrolyzed silane is added, and the mixture is allowed to stir overnight at room temperature. In the morning, the aluminum slurry is then poured into large crystallizing dish; the flask is washed with additional isopropanol, which is also added to the crystallizing dish. The dish is placed in a lab hood for several hours to allow the functionalized aluminum flake to settle. The clear supernatant liquid is then siphoned off and discarded. The silane treated aluminum flakes in the dish are allowed to dry overnight. In the morning, the crystallizing dish is placed into a vacuum oven preheated to 120 °C and maintained at that temperature under vacuum for about one hr. After removing the crystallizing dish from the oven and cooling to room temperature, the treated aluminum flakes are scraped from the dish using a spatula and transferred to a tared vial, yielding 22.5 g of phenethyl, trimethoxysilane functionalized aluminum flakes. Example 9

Encapsulated metallic-look pigment is prepared from the phenethyl, trimethoxysilane functionalized aluminum flakes synthesized in Example 8 according to the following batch-mode suspension polymerization procedure:

2000 g of 0.25 percent aqueous hydroxypropyl methyl cellulose ether (METHOCEL E50) solution is charged to a 1 gallon (4 liter) stainless steel autoclave reactor fitted with an upward pumping, turbine type agitator. 6.84 g aqueous sodium dichromate (65 percent by weight) solution is added to the aqueous load to inhibit emulsion polymer formation. The reactor is equipped with a jacket through which thermostatically controlled heat transfer fluid is circulated. A monomer mixture for polymerizing cross-linked polystyrene beads was prepared, comprising:

285.15 g styrene monomer 45.05 g DVB 1.765 g TBPO

15.O g phenethyl, trimethoxysilane functionalized aluminum flakes are weighed into a transfer container. Approximately half of the above styrene/DVB/TBPO monomer mixture was then poured into the transfer container containing the functionalized aluminum flakes, the container is swirled to distribute the pigment, and this slurry is transferred to the reactor while agitator is spinning at 120 rpm. The remainder of the monomer mixture is poured into the transfer container, swirled, and transferred into the reactor to complete the addition of monomer and pigment into the reaction mixture. The headspace above the liquid in the reactor is inerted with nitrogen gas and the agitator speed is increased to 300 rpm. The temperature of the reactor is then increased from 20 ⁰C to 74 °C over the course of one hr., and is maintained at 74 °C for about 7 hr. Afterwards, the reactor is rapidly cooled to 20 °C; stirring of the contents is continued until the product is removed.

The reaction mixture is discharged from the reactor through a bottom mounted valve as a homogeneous grayish liquid. Upon standing, this mixture separates into a cloudy, orange aqueous phase above a grayish-silver precipitate, which rapidly sinks to the bottom of the container. The aqueous phase is discarded and the precipitate is washed well with deionized water. The wet product is then dried overnight in a forced air convection oven at 70 ⁰C to give a grayish silver, free flowing powder which sparkles when illuminated. The total quantity of product recovered is 294.6 g. Characterization by optical microscopy shows the product to comprise round beads comprising encapsulated functionalized aluminum flakes. Characterization of the mean particle size using a Beckman Coulter Counter yielded a volume median particle diameter of 120 microns. Example 10 Aluminum flakes are functionalized using a variation of the hydrolyzed silane procedure of Example 6 with the exception that the aluminum flakes are first coated with a layer of silica (SiO₂) before functionalizing with fully hydrolyzed silane.

Hydrolyzed silane is prepared as follows. 0.5 g glacial acetic acid and 2.5 g deionized water are weighed into a 30 ml glass jar and mixed using a magnetic stir bar. 10.0 g of 3- TMSPM is then added using a syringe, and stirring is continued. While initially a two phase mixture, after stirring for about an hour, the two phases come together to form a light yellow, clear solution of hydrolyzed silane having a higher viscosity.

20.0 g aluminum flakes in mineral oil (SILBERLINE SSP-860-20-C) are weighed into a single necked 1000 ml round bottom flask. 400 ml. reagent grade isopropanol and a magnetic stir bar are added to the flask and the slurry is stirred on a magnetic stir plate for about 15 min. The flask is then allowed to sit in a lab hood to allow the aluminum flakes to settle for about two hr. The clear supernatant liquid above the silvery precipitate is then removed by pipette and discarded. A further 400 ml isopropanol is added to the aluminum in the flask, stirred, and allowed to settle as above. The supernatant liquid is siphoned off as above and the precipitate is washed with two further isopropanol washes using the same procedure.

A diluted sodium silicate solution is prepared by combining 20 g sodium silicate stock solution (13.6 percent NaOH and 12.6 percent Si) with 180 ml deionized water and stirring thoroughly. 25 g of this diluted sodium silicate solution is added to the aluminum slurry after the fourth addition of 400 ml isopropanol. While stirring using a magnetic stir bar, the pH of the slurry is reduced to 5.0 by drop wise addition of glacial acetic acid, and the mixture is allowed to stir overnight. In the morning, the aluminum slurry is then poured into large crystallizing dish; the dish is placed in a lab hood for several hours to allow the silica treated aluminum flakes to settle. The clear supernatant liquid is then siphoned off and discarded. The silica treated aluminum flakes in the dish are allowed to dry overnight. In the morning, the crystallizing dish is placed into a vacuum oven preheated to 100 ⁰C and maintained at that temperature under a vacuum for one hr. After removing the crystallizing dish from the oven and cooling to room temperature, the silica coated aluminum flakes are scraped from the dish as silvery-white flakes.

The silica coated aluminum flakes are added to a 1000 ml round bottom flask along with a magnetic stir bar. 400 ml isopropanol and 5.0 g of the hydrolyzed 3-TMSPM silane are added and the mixture is allowed to stir overnight at room temperature. In the morning, the aluminum slurry is then poured into large crystallizing dish; the flask is washed with additional isopropanol, which is also added to the crystallizing dish. The dish is placed in a lab hood for several hours to allow the aluminum to settle. The clear supernatant liquid is then siphoned off and discarded. The silane treated aluminum flakes in the dish are allowed to dry overnight. In the morning, the crystallizing dish is placed into a vacuum oven preheated to 120 °C and maintained at that temperature under a vacuum for one hr. After removing the crystallizing dish from the oven and cooling to room temperature, the treated aluminum is scraped from the dish using a spatula and transferred to a tared vial, yielding 15.9 g. of silica coated, 3-TMSPM functionalized aluminum flakes. Example 11 Encapsulated metallic-look pigment is prepared from the silica coated, 3-TMSPM functionalized aluminum flakes of Example 10 according to the following batch-mode suspension polymerization procedure:

2000 g 0.25 percent aqueous hydroxypropyl methyl cellulose ether (METHOCEL E50) solution is charged to a 1 gallon (4 liter) stainless steel autoclave reactor fitted with an upward pumping, turbine type agitator. 6.84 g aqueous sodium dichromate (65 percent by weight) solution is added to the aqueous load to inhibit emulsion polymer formation. The reactor is equipped with a jacket through which thermostatically controlled heat transfer fluid is circulated. A monomer mixture for polymerizing cross-linked polystyrene beads was prepared, comprising: 285.15 g styrene monomer

45.05 g DVB

1.765 g TBPO 15.0 g silica coated, 3-TMSPM functionalized aluminum flakes are weighed into a transfer container. Approximately half of the above styrene/DVB/TBPO monomer mixture is then poured into the transfer container containing the functionalized pigment, the container is swirled to distribute the pigment, and this slurry is transferred to the reactor while agitator is spinning at 120 rpm. The remainder of the monomer mixture is poured into the transfer container, swirled, and transferred into the reactor to complete the addition of monomer and pigment into the reaction mixture. The headspace above the liquid in the reactor is inerted with nitrogen gas and the agitator speed is increased to 300 rpm. The temperature of the reactor is then increased from 20 °C to 74 °C over the course of one hr., and is maintained at 74 °C for about 7 hr. Afterwards, the reactor is rapidly cooled to 20 ⁰C; stirring of the contents is continued until the product is removed.

The reaction mixture is discharged from the reactor through a bottom mounted valve as a homogeneous grayish liquid. Upon standing, this mixture separates into a cloudy, orange aqueous phase above a grayish-silver precipitate, which rapidly sinks to the bottom of the container. The aqueous phase is discarded and the precipitate is washed well with deionized water. The wet product is then dried overnight in a forced air convection oven at 70 °C to give a grayish silver, free flowing powder which sparkles when illuminated. The total quantity of product recovered is 271.5 g. Characterization by optical microscopy shows the encapsulated metallic-look pigment to comprise round beads containing functionalized aluminum pigment. Characterization of the mean particle size using a Beckman Coulter Counter yields a volume median particle diameter of 125 microns. Examples 12 and 13

Example 12 is ground polystyrene resin (STYRON™ 666D a clear, general purpose, molding grade polystyrene resin available from The Dow Chemical Company, which is ground into a powder) dry blended with SILBERLINE SSP-860-20-C. Example 13 is ground STYRON 666D polystyrene resin dry blended with the encapsulated metallic-look pigment from Example 3 which comprises 2 percent by weight aluminum flake encapsulated in a cross-linked polystyrene. Each composition comprises about 0.5 weight percent aluminum flake. The amounts of ground polystyrene and pigments for Examples 12 and 13 are shown in Table 1. Table 1

The dry blends are hand shaken in a sealed container to disperse the pigment and melt compounded in a Brabender 0.75 inch (in) single screw extruder at a screw speed of 50 rpm with a melt temperature of 225 °C. The molten strand issuing from the die is cooled by passage through a water bath and comminuted to pellets.

The resulting pellets are injection molded on a Battenfeld injection molding machine using a double gated t-bar mold with two inserts yielding a pair of holes in the thin, center section of the molded parts. The molding conditions are as follows: Melt temperature of 220 ⁰C and Mold temperature of 49 °C.

As shown in Figure 3, weld lines for Example 12, containing the conventional aluminum flake pigment, are easily visible as a dark line at the center of the part 10 and as lines connecting each of the insert holes with the central weld line 11. For Example 13 prepared using the encapsulated metallic-look pigment of the present invention, the weld line and area between the holes was uniformly colored and virtually indistinguishable from the rest of the molded bar, Figure 4. Example 14

An epoxy coating powder containing 15 percent of 10 micron aluminum flake is used as feedstock. This powder is obtained from conventional powder-coating manufacturing, using a novolac modified epoxy containing a solid amine crosslinker

(DICY). The aluminum flake is pre-treated with a functionalizing compound. The powder has 19 seconds to gel at 180 °C and contains a high loading of 2-methyl imidazole accelerator.

The epoxy coating powder is mixed in 50 percent latex DL-510. DL-510 latex particles consist of 69 percent styrene, 28 percent butadiene and 3 percent acrylic acid. After intensive mixing the latex-epoxy mixture is dried at room temperature for 24 hours. After room temperature drying, the latex-epoxy mixture is put in an oven and dried at 170 °C for 20 min. After cooling and pelletizing, one obtains pellets comprising 75 percent cured epoxy grits in a styrenic matrix. bxamples 15 and 16

5 percent of Example 14 is compounded in styrene-acrylonitrile copolymer (Example 15) and in polycarbonate (Example 16). Examples 15 and 16 are injection molded using a mold which contains an insert for creating a weld line. The obtained plaques show an overall metallic-look with a homogeneous appearance in the area of the weld line.

Claims

CLAIMS:

1. An encapsulated metallic-look pigment comprising: i at least one metallic-look pigment particle and ii an encapsulating material surrounding at least part of the metallic-look pigment particle wherein the metallic-look pigment particle is coated with a functionalizing compound.

2. The encapsulated metallic-look pigment of Claim 1 wherein the encapsulated metallic-look pigment has an isometric shape having dimensions X, Y, and Z in three spatial directions, and each dimension is within +/- 25 percent of the other two dimensions.

3. The encapsulated metallic-look pigment of Claim 1 wherein the metallic-look pigment particle is a metal pigment, a metal oxide-coated glass platelet pigment, a goniochromatic lustrous pigment, an interference pigment, a pearlescent pigment or a liquid-crystal pigment.

4. The encapsulated metallic-look pigment of Claim 1 wherein the metallic-look pigment particle is a metal pigment selected from the group consisting of aluminum, copper, zinc, tin, gold, nickel, iron, chromium, and alloys thereof.

5. The encapsulated metallic-look pigment of Claim 1 wherein the metallic-look pigment particle is aluminum flake.

6. The encapsulated metallic-look pigment of Claim 1 wherein the metallic-look pigment particle(s) have a mean length of from 0.1 microns to 300 microns and an aspect ratio of from 1 to 10,000.

7. The encapsulated metallic-look pigment of Claim 1 wherein the functionalizing compound is a titanium coupling agent, an aluminum coupling agent, an aluminum chelating agent, a mineral oil, a silicon containing compound, a molecule comprising a long alkyl chain and a polar end group, or mixtures thereof.

8. The encapsulated metallic-look pigment of Claim 1 wherein the functionalizing compound is a silicon-organic compound.

9. The encapsulated metallic-look pigment of Claim 8 wherein the silicon-organic compound is tetraethoxysilane, n-octyl-triethoxysilane, iso-octyl-trimethoxysilane, propyl- trimethoxysilane, dimethyl-dimethoxysilane, methyl-triethoxysilane, cyclohexyl- trimethoxysilane, phenyl-trimethoxysilane, diphenyl-dichlorosilane, 3 -aminopropyl- trimethoxysilane, N-methyl- 3 -aminopropyltrimethoxysilane, 3-aminopropyl- triethoxysilane, 3-aminopropyl-tris (2-methoxy-epoxy-ethoxy-silane), N-aminoethyl- 3- aminopropyltrimethoxysilane, 3-acryloxypropyl-trimethoxysilane, 3 -glycidyloxypropyl- trimethoxysilane, 3-mercaptopropyl-trimethoxysilane, 3-mercaptopropyl- triethoxysilane, 3 -mercaptopropyl-methyldimethoxysilane, vinyltrichlorsilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris (2-methoxyethoxy) silane, 3-methacryloxypropyl- trimethoxysilane, or mixtures thereof.

10. The encapsulated metallic-look pigment of Claim 1 wherein the encapsulating material is glass, an inorganic crystal, a thermoset plastic, or a thermoplastic.

11. The encapsulated metallic-look pigment of Claim 1 wherein the encapsulating material is a thermoplastic.

12. The encapsulated metallic-look pigment of Claim 1 wherein the encapsulating material is a polycarbonate, a copolyester carbonate, a polymethyl methacrylate, a polyetherimide, a transparent polyimide, a halo olefin polymer, a transparent polyamides, a polyester, a polysulfone, a polyether, a polyphenyl sulfone, a transparent acrylonitrile butadiene styrene, a styrene acrylonitrile, a polystyrene, a cellulosic, a miscible transparent polystyrene-polyphenylene oxide blend, an acrylic, a polycarbonate-polysiloxane, a polyetherimide-polysiloxane, a polyarylate, or blends thereof.

13. The encapsulated metallic-look pigment of Claim 1 wherein the encapsulating material is a suspension polymerized polystyrene.

14. The encapsulated metallic-look pigment of Claim 1 wherein the encapsulating material is cross-linked.

15. The encapsulated metallic-look pigment of Claim 1 having a minimum dimension of 10 microns and a maximum dimension of 300 microns.

16. The encapsulated metallic-look pigment of Claim 1 having a minimum dimension of 25 microns and a maximum dimension of 100 microns.

17. The encapsulated metallic-look pigment of Claim 1 having dimensions X, Y, and

Z in three spatial directions, and each dimension is within +/- 15 percent of the other two dimensions.

18. The encapsulated metallic-look pigment of Claim 1 having dimensions X, Y, and Z in three spatial directions, and each dimension is within +/- 5 percent of the other two dimensions.

19. The encapsulated metallic-look pigment of Claim 1 wherein the isometric shape is a polyhedron, a cube or a sphere. W

20. The encapsulated metallic-look pigment of Claim 1 wherein the isometric shape is a sphere.

21. The encapsulated metallic-look pigment of Claim 1 comprising from 1 to 15 metallic-look pigment particles.

22. A process to make an encapsulated metallic-look pigment comprising the steps of coating a metallic-look pigment particle with a functionalizing compound and encapsulating the coated metallic-look pigment particle in an encapsulating material.

23. The process of Claim 22 wherein the encapsulated metallic-look pigment has an isometric shape having dimensions X, Y, and Z in three spatial directions, and each dimension is within +/- 25 percent of the other two dimensions.

24. The process of Claims 22 or 23 wherein the encapsulating material is a suspension polymerizable thermoplastic.

25. The process of Claims 22 or 23 further comprising the steps of: i forming a reaction mixture by a dispersing the metallic-look pigment particle in an organic medium containing one or more monomers to form a pigment/organic monomer slurry, b adding the pigment/organic monomer slurry to an aqueous system containing one or more suspension stabilizing agents forming a two phase hydrophilic/hydrophobic mixture, c agitating the two phase hydrophilic/hydrophobic liquid mixture to break up the pigment/monomer slurry into small droplets, ii initiating polymerization of the small droplets in the reaction mixture by increasing the temperature of the system to a level where autopolymerization begins in the monomer, and iii isolating the encapsulated metallic-look pigment as a wet cake, iv washing the wet cake with water, and v drying the retained solids.

26. The process of Claim 25 further comprising the step of d adding a free radical initiator to the reaction mixture.

27. The process of 25 further comprising the step of e adding one or more bi- or multifunctional species which cause the polymerizing droplets to gel or crosslink into a network structure.

28. The encapsulated metallic-look pigment of Claim 1 incorporated into a thermoplastic, a thermoset plastic, a paint, an ink, a toner, a cosmetic, a glue, or a paste.

29. The encapsulated metallic-look pigment of Claim 1 incorporated into a polycarbonate, a copolyester carbonate, a polymethyl methacrylate, a polyetherimide, polyimides, a halo olefin polymer, a polyamide, a polyester, a polysulfone, a polyether sulfone, a polyphenyl sulfone, an acrylonitrile butadiene styrene terpolymer, a styrene acrylonitrile copolymer, a polystyrene, a cellulosic, a polyphenylene oxide, a polyphenylene ether, an acrylic, a polysiloxane, a polyarylate, a thermoplastic polyurethane, a polyethylene, a polypropylene, and blends thereof.

30. A cosmetic composition comprising the encapsulated metallic-look pigment of

Claim 1.

31. A paint composition comprising the encapsulated metallic-look pigment of Claim 1.

32. An ink composition comprising the encapsulated metallic-look pigment of Claim 1.

33. A toner composition comprising the encapsulated metallic-look pigment of Claim 1.

34. A thermoset plastic composition comprising the encapsulated metallic-look pigment of Claim 1.

35. A thermoplastic composition comprising the encapsulated metallic-look pigment of Claim 1.

36. The plastic composition of Claims 34 or 35 wherein the encapsulated metallic- look pigment is present in an amount of from 1 to 99 parts by weight and the plastic is present in an amount of from 99 to 1 parts by weight based on the total weight of the composition.

37. The plastic composition of Claims 34 or 35 wherein the encapsulated metallic- look pigment is present in an amount of from 1 to 50 parts by weight and the plastic is present in an amount of from 99 to 50 parts by weight based on the total weight of the composition.

38. The plastic composition of Claims 34 or 35 wherein the encapsulated metallic- look pigment is present in an amount of from 1 to 25 parts by weight and the plastic is present in an amount of from 99 to 75 parts by weight based on the total weight of the composition.

39. A fabricated thermoset plastic article comprising the encapsulated metallic-look pigment of Claim 1.

40. A fabricated thermoplastic article comprising the encapsulated metallic-look pigment of Claim 1.

41. The fabricated thermoplastic article of Claim 40 produced by injection molding, blow molding, extrusion, thermoforming, or combinations thereof.

42. The fabricated plastic article of Claims 39 or 40 is an automotive article, a lawn and garden article, a boat article, a snowmobile article, a personal water craft article, an enclosure for a computer, an enclosure for a computer accessory, an enclosure for a printer, an enclosure for a copier, an enclosure for a fax machine, an enclosure for a cell phone, an enclosure for a hand held personal data assistant, an enclosure for a television set, an enclosure for a audio system, a housing for a telephone, a housing for a small electrical appliance, a housing for an electrical tool, a washing machine cover, a dryer cover, a refrigerator cover, a freezer cover, a dish washer cover, a toy, a comb, a brush handle, a tooth brush handle, a cosmetic container, a ski boot, a sink, a toilet, a bath surround, a shower surround, or furniture.