Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K9/00—Screening of apparatus or components against electric or magnetic fields
  • H05K9/0067—Devices for protecting against damage from electrostatic discharge
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B1/00—Layered products having a non-planar shape
  • B32B1/08—Tubular products
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
  • B65D1/34—Trays or like shallow containers
  • B65D1/36—Trays or like shallow containers with moulded compartments or partitions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
  • C08J5/10—Reinforcing macromolecular compounds with loose or coherent fibrous material characterised by the additives used in the polymer mixture
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/10—Metal compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]

Definitions

• Read/Write heads are electronic components that read information on magnetic media and/or write information onto magnetic media.
• Read Write heads are used in many electronic devices and are commonly used in computers to read and write information to and from a computer's memory. Complicated assembly lines are typically used to make the Read/Write heads and to install them into electronic components.
• the Read Write heads are stored and transported in special Read/Write head trays that facilitate shipping the heads and processing them at the assembly line. Most Read/Write head trays must prevent any electrostatic discharge (ESD).
• ESD electrostatic discharge
• a tray is made ESD-safe by making the surface that the Read/Write head rests upon into a conductive surface. A conductive surface allows static electricity to dissipate so that a static charge can not build up on the surface.
• the Read/Write heads are dark-colored and small; in appearance, they resemble black peppercorns.
• the Read/Write heads are therefore difficult to see if the tray has a dark color.
• a dark color makes it difficult to verify that the read/write heads are present in the tray and to remove them from the tray, especially when machine vision is used.
• Read/Write head trays are conventionally from a material made by mixing a polymer with stainless steel.
• the stainless steel is sometimes referred to as a filler because it supplements the polymer's electrical properties by making the polymer into a conductive ESD safe material.
• the stainless steel is conductive and performs well at high temperatures, but, without pigment, creates a dark color.
• Stainless steel is difficult to mix with a polymer to achieve a uniform distribution of stainless steel. Without a uniform distribution, the material is more prone to have small insulated spots that compromise the ESD-safe properties of the material. Further, the stainless steel has magnetic properties that could potentially damage the Read/Write heads.
• materials made with stainless steel require high concentrations of pigments to color them, so that other properties of the material are compromised.
• Read/Write head trays that avoid the use of stainless steel. Instead of stainless steel, metal oxide fillers are used; consequently, the materials are colorable.
• the materials are colorable because they are light-colored and do not require high concentrations of pigments to color them.
• the materials for making the trays are preferably made with a high temperature, high strength polymer and a metal oxide.
• a preferred embodiment of the invention is a Read/Write head tray, at least a portion of the tray comprising an electrostatic discharge-safe surface for receiving a Read Write head, with the surface being made of a mixture of at least one high temperature, high strength polymer and at least one metal oxide.
• the lightness of the color of the materials may be measured and assigned an L value in the CIE L*a*b* index (see discussion, below), e.g., more than about 55.
• Certain embodiments relate to a colored article for receiving electronic components that is a tray having a plurality of pockets that each have an electrostatic discharge-safe surface that comprises a mixture of at least one high temperature, high strength polymer, at least one metal oxide, and at least one pigment. Certain embodiments relate to a set of trays for electronic component processing, the set having at least two subsets of trays wherein each tray has a plurality of pockets that each comprises an electrostatic discharge-safe surface, with each subset comprising a subset color distinct from the other subset colors.
• Certain embodiments relate to an article for receiving electronic components, the article having a structure for contacting and supporting an electronic component, and with the structure comprising at least one electrostatic discharge-safe surface that comprises a mixture of at least one high temperature, high strength polymer and at least one metal oxide, wherein the surface has an L value of more than about 55 or 65. Certain embodiments relate to an article for receiving electronic components, the article comprising a tray having a plurality of pockets, each pocket comprising at least one electrostatic discharge-safe surface that comprises a mixture of at least one high temperature, high strength polymer at least one metal oxide, and at least one pigment, wherein the surface has an L value of more than about 55 or 65.
• Certain embodiments relate to a method of producing an article for electronic processing, the method comprising: molding a tray having a pocket that comprises an electrostatic discharge-safe surface that comprises a high temperature, high strength polymer and a conductive filler, wherein the surface comprises, an L value of at least about 55 or 65, and a resistivity in the range of 10 3 to 10 14 ohms per square, wherein the surface is flatter than an average of about 0.1 or 0.015 inches per inch.
• Certain embodiments relate to a method of producing an article for electronic processing, the method comprising molding a tray having a pocket that comprises an electrostatic discharge-safe surface that comprises a high temperature, high strength polymer and a conductive filler, wherein the surface comprises, an L value of at least about 55 or 65, and a resistivity in the range of 10 3 to 10 1 ohms per square, wherein the surface is flatter than an average of about 0.1 or 0.015 inches per inch.
• Figure 1 depicts the coordinate system for 1976 CIE L*a*b* Space and the L value for certain embodiments
• Figure 2 depicts a multipocketed tray for receiving electrical components
• Figure 3 depicts a cross-section of Figure 2 in a view as indicated by line 3-3 in Figure 2;
• Figure 4 depicts a plurality of the trays of Figure 2 in a stacked configuration.
• a preferred embodiment of the invention is an ESD-safe Read/Write head tray that is light in color, is made of a high temperature, high strength polymer, and contains a metal oxide filler.
• the metal oxide filler preferably includes ceramics. The lightness of the color of a material is objectively quantifiable using the
• L is used herein for the 1976 CIE L*a*b* system: elsewhere, L* may be used to refer to the same value described herein as “L”.
• the a* axis indicates the amount of red or green and the b* axis indicates the amount of yellow or blue. Thus a value of 0 for both "a*" and "b*" indicates a balanced gray. Since the CLELab system is device- independent, it is a popular choice for computer imaging applications. The CLELab values are measurable using standardized tests that are familiar to those skilled in these arts, for example, by using a reflectance meter.
• reflectance meters are manufactured by Photovolt Instruments, Inc., Minneapolis, MN, (Photovolt Model 577 and by Minolta Corporation, Ramsey, NJ, (model Minolta CM 2002).
• L is an objective, quantifiable, and reproducible measure of the lightness of any color.
• an L value that ranges from essentially 0 to about 100.
• a very dark, near black, color may be achieved by mixing polymers with carbon black to achieve an L value of close to 0.
• white pigments e.g., titanium oxides
• An example of an electrostatic discharge-safe material suitable for use as a support for electronic component processing having a light color is a polyetheretherketone mixed with about 54% by weight antimony-doped tin oxide conductive material, which has an L value of 64.9, see "65" in Figure 1, as measured using a reflectance spectrophotometer with output programmed for the CIELab system.
• the other samples described herein have been visually determined to fall within the ranges as set forth, below.
• certain embodiments set forth herein provide for materials having a high L value while maintaining suitable mechanical and electrostatic discharge-safe conductive properties. Moreover, certain embodiments retain moldability characteristics such as flatness.
• An aspect of certain of these embodiments is the use of metal oxides or ceramics to achieve the electrostatic discharge-safe and coloration properties.
• Another aspect of certain of these embodiments is the use of high temperature, high strength polymers.
• Another aspect of certain of these embodiments is the use of isotropic flow particles. All ranges in the continuum from about 0 to about 100 are contemplated. Other embodiments achieve colorations having an L value of at least about 33, about 45, about 55, about 66, or about 80.
• Some embodiments have colorations that fall within an L value ranging from about 45 to about 100, from about 55 to about 99, and from about 66 to about 90.
• a material with an L value of more than about 55 would mean that the material in question was closer to white on the CIELab scale than a material with an L value of about 55.
• the conductive, polymeric, and conductive material concentrations are adjusted until a desired combination of mechanical, color, or conductive properties are achieved for the contemplated application. Such adjustment could readily be performed by a person of ordinary skill in these arts after reading this disclosure.
• a high temperature, high strength polymer is preferably one having high resistance to heat and chemicals.
• the polymer is preferably resistant to the chemical solvent N- methyl pyrilidone, acetone, hexanone, and other aggressive polar solvents.
• a high temperature, high strength polymer has a glass transition temperature and/or melting point higher than about 150° C. Further, the high strength, high temperature polymer preferably has a stiffness of at least 2 GPa.
• high temperature, high strength polymers are polyphenylene oxide, ionomer resin, nylon 6 resin, nylon 6,6 resin, aromatic polyamide resin, polycarbonate, polyacetal, polyphenylene sulfide (PPS), trimethylpentene resin, polyetheretherketone (PEEK), polyetherketone (PEK), polysulfone (PSF), tetrafluoroethylene/ perfluoroalkoxyethylene copolymer (PFA), polyethersulfone (PES), high-temperature amorphous resin (HTA), polyallylsulfone (PASF), polyetherimide (PEI), liquid crystal polymer (LCP), polyvinylidene fluoride (PVDF), ethylene/tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene/hexafluoropropylene copolymer (FEP), tetrafluoroethylene/ hexafluoropropylene/perfluoroalkoxyethylene ter
• Mixtures, blends, and copolymers that include the polymers described herein may also be used.
• Especially preferable are PEK, PEEK, PES, PEI, PSF, PASF, PFA, FEP, HTA, LCP and the like.
• high temperature, high strength polymers are also given in, for example, U.S. Patent Nos. 5,240,753; 4,757,126; 4,816,556; 5,767,198, and patent applications EP 1 178 082 and PCT/US99/24295 (WO 00/34381) which are hereby incorporated herein by reference.
• a metal oxide filler is a conductive material that includes metal oxide and can be added to a high temperature, high strength polymer to create an ESD safe material having a light color and sufficient mechanical properties for use as a Read/Write head tray.
• the metal oxides are preferably mixed with ceramics or coated upon ceramics e.g., metal oxide doped ceramics.
• Such fillers typically have a light color that allows them to be used to make a light colored material. Since they have a light color, other coloring agents may be added to impart a particular color to the material. Further, ceramics are durable, and metal oxide/ceramic combination materials typically have electroconductive properties that are independent of humidity.
• a ceramic is a material consisting of compounds of a metal combined with a non-metallic element. Ceramics include metal oxides.
• metal oxides examples include aluminum borate, zinc oxide, basic magnesium sulfate, magnesium oxide, potassium titanate, magnesium borate, titanium diboride, tin oxide, and calcium sulfate. This list of oxides is exemplary and not intended to limit the scope of the invention. Further examples of fillers are provided in, for example, U.S. Patent Nos. 6,413,489; 6,329,058; 5,525,556; 5,599,511; 5,447,708; 6,413,489; 5,338,334; and 5,240,753, which are hereby incorporated herein by reference. In general, the metal oxides may be doped or coated with another metal as needed to impart or enhance conductivity.
• a preferred filler is tin oxide, particularly antimony-doped tin oxide, for example, the family of products provided under the trade name Zelec® by Milliken Chemical Co. These products are small, roughly spherical-shaped, and light blue-gray to light green-gray in color. These colors allow for the creation of materials with a wide range of light colors, including white. Further, the antimony-doped tin oxide materials can be used to make transparent films and have the advantages of most ceramics, such as, non corrosiveness, resistance to acids, bases, oxidizers, high temperatures, and many solvents.
• whiskers are also preferred classes of fillers, especially titanate whiskers, and more particularly potassium titanate and aluminum borate whiskers, which are described in, for example, U. S. Patent Nos. 5,942,205 and 5,240,753, which are hereby incorporated herein by reference.
• the term whisker refers to a single crystal filament having a cross- sectional area of up to about 8xl0 "5 of a square inch and a length of about at least 10 times the average diameter. Whiskers are typically free of flaws and are therefore much stronger than polycrystals that have a similar composition. Thus certain whisker fillers can improve the strength of a composite material as well as impart other properties such as improved rigidity, abrasion resistance, and electrostatic dissipation.
• a preferred class of whiskers are provided under the trade name DENT ALL by Otsuma Chemical Co., Japan; these are ceramic whiskers coated with a thin layer of tin oxide.
• the sizes and shapes of the fillers are not limited and may be e.g., whiskers, spheres, particles, fibers, or other shapes.
• the sizes of the fillers are not limited, but small particles such as whiskers or comparably sized spheres, or very small sizes are preferable. Technologies for making very small particles, e.g., using nanotechnology, may be employed.
• Suitable metal oxide fillers may be disposed in a variety of configurations.
• an inert core particle may be coated with a metal oxide. The metal oxide coating is thus extended by the inert particle to result in a less expensive product.
• a hollow core may be used instead of an inert particle.
• the size of the particles may be made smaller by omitting the core.
• a ceramic may be doped with a metal oxide. Doped materials can be conductive while retaining the mechanical and coloring properties of the ceramic.
• the metal oxide conductors should be disbursed in the material so that three- dimensional interconnecting networks of the conductors are formed. The networks serve as a circuit to drain static charges.
• the concentration of the metal oxide conductors is related to the ESD properties of the material. Very low concentrations of metal oxide conductors create a high surface resistivity. The resistivity drops slowly as the concentration of metal oxide conductors is increased until a "percolation threshold" is reached when the metal oxide conductors begin touching each other and further increases in the metal oxide conductor concentration cause rapid drops in resistivity. Eventually, a ceramic concentration is reached wherein further increases in the metal oxide conductor concentration fails to create substantial drops in resistivity because the metal oxide conductors have aheady formed an optimal number of networks. Typically, the addition of materials having less conductivity than the metal oxide conductors will result in increased surface resistivity.
• the addition of pigments can affect surface resistivity but compositions that have a desired resistivity can be made by adjusting the amounts of pigment and conductive filler.
• a light-colored material for a Read/Write head tray One advantage is that the Read/Write heads may be visualized. Another advantage is that the trays are colorable. Thus the color may be optimized to make the heads more easily visible. Or different types of Read/Write head trays may be made with different colors so that different models and applications of trays maybe easily recognized by a user. Or various types or sizes of heads may be stored in trays of different colors so that shipping and use of the heads is efficient.
• Certain embodiments further incorporate pigments to achieve not only a desired L value, but also a particular color, e.g., red, green, blue, yellow, or combinations thereof.
• the pigments are added in a concentration suitable to achieve the desired color.
• the desired coloration may be accomplished by adding pigments known to those skilled in these arts, and mixing them with conductive materials and polymers as described herein to achieve a desired color, conductivity, and mechanical characteristics.
• pigments include titanium dioxide, iron oxide, chromium oxide greens, iron blue, chrome green, aluminum sulfosilicate, cobalt aluminate, barium manganate, lead chromates, cadmium sulfides and selenides.
• Carbon black may be used if a black color is desired or if the carbon black is used in concentrations that do not create an overly dark or black color. Colors that may be achieved with the use of pigments spans the spectrum of visible light, including white.
• the filler(s) are preferably present in amounts sufficient to make the Read/Write head tray have a surface resistivity in the range of about 10 3 to about 10 14 ohms per square, a range that embues the surface with ESD-safe properties; more preferably the surface resistivity is in the range between about 10 4 to less than about 10 7 ohms per square. Further, the filler is preferably evenly distributed through the material so as to avoid small insulated spots that compromise its ESD-safe properties.
• the filler is preferably present in the concentration that avoids creating a black color in the material, and more preferably avoids creating a dark color in the material.
• concentration of carbon black that is required to make an ESD safe material causes the material to be dark, and essentially black.
• Microchip trays are conventionally made with carbon black. A material made of a polymer and a carbon filler is commonly used to make microchip trays for holding microchips. Prior art microchip trays, however, are not suitable for use as Read/Write head trays because the microchip trays are very dark colored due to the presence of the carbon filler. In a microchip tray, the Read/Write heads would be difficult to see because the Read/Write heads are small and dark and the microchip tray is dark.
• an acceptable chip tray surface resistivity is usually in the range of at least about 10 to 10 per square.
• an acceptable read/write head tray surface resistivity is usually in the range of about 10 4 to less than about 10 7 ohms per square. Since a conductive material must be added to a polymer to create an ESD safe material, and material with a resistivity of, e.g., 10 8 ohms per square has more filler than a material with a resistivity of, e.g., 10 4 ohms per square.
• high temperature, high-strength polymers may be mixed with more than about 40% ceramics by weight to achieve an ESD safe material without losing desirable processing properties such as moldability and flowability and without losing desirable mechanical properties such as compressive and tensile strength and appropriate rigidity.
• This result is surprising because, although polymers may be mixed with moderate amounts of non polymeric materials without losing the desirable properties of the polymer in the final product, the addition of a large amount of non polymeric materials, i.e. more than about 40% by weight, would be expected to result in a final product with properties that did not resemble those of the polymer. Ceramics treated with, or doped with, metal oxides are preferable for creating ESD safe materials.
• the preferred concentration range of ceramics is between about 40% and about 75%, a more preferred concentration range is between about 45% percent and about 70%, and a yet more preferable range is between about 50% and about 60%.
• flat is thus not to be confounded with measures of roughness.
• Flatness is a desirable feature of Read/Write head trays.
• One possible reason for the unexpected flatness is that the metal oxides used in the flat surfaces had isotropic flow shapes.
• An isotropic flow shape is a shape that resists becoming oriented in any particular direction as a result of forces created by a flowing fluid; in other words the flow characteristics of the particle are approximately the same in all directions.
• a spherical particle has an isotropic flow shape , because the particle does not become oriented in any particular direction when the particle is mixed in a flowing fluid.
• a rod-shaped particle does not have an isotropic flow shape because it tends to align its longest axis in the direction parallel to the direction of flow.
• a tray includes an electrostatic discharge-safe surface that receives and contacts an electronic component to thereby support it.
• Trays have a plurality of pockets, for example, as in Figures 2 and 3.
• the component is contained by the tray pocket, which may be, for example, an indentation, a space surrounded by walls, posts, or protrusions, a groove, or other structure that limits the component's mobility while on the tray so that the tray can successfully be moved without dislodging the component from the tray.
• Trays are preferably stackable ( Figure 4) and the stacks are preferably also stackable, e.g., on pallets, so as to facilitate processing.
• a surface may comprise a material by molding the surface from the material.
• the materials in the surface are known if the material from which the surface is molded are known.
• a surface may be assumed to resemble a material's bulk composition, even though it is appreciated that the very uppermost portions of a surface can have a composition that is distinct form the bulk of the material.
• a surface may be determined to have an average flatness that is measurable in inches per inch. Conventional flatness measurements or L value colorimetric measurements may be used that provide an average for a significant portion of the surface. Such measurements can thus be distinguished from measurements that provide an average for a very small portion of the surface, e.g., atomic force microscopy.
• FIGS 2-4 depict a tray 100 having a plurality of pockets 180.
• the pockets 180 have bottom surfaces 120 that form sides 102 that contain objects on the bottom surfaces 120.
• the top surface 132 of tray 100 is continuous and defines separations between pockets 180.
• Outer edge 116 of top surface 132 is continuous with and pe ⁇ endicular to upper tray side 122.
• Tray side 122 is pe ⁇ endicular to lip 112.
• Lip 112 is pe ⁇ endicular to lower tray side 114.
• trays 100 may be placed in a stacked configuration 101 without bottom tray surface 126 impinging on an electrical component, e.g., depicted by 208. Lip 112 acts as a stop for bottom tray surface 126.
• Prototype Read/Write head trays were prepared by molding them from a mixture of metal oxide ceramics with PEEK, as indicated in Table 1.
• the molding process was essentially the same as the process used for PEEK loaded with stainless steel, although the molding temperature was adjusted slightly downwards.
• the results of these experiments showed that Zelec® ECP 1410T was a preferable metal oxide ceramic for use in making light colored Read/Write head trays.
• the high temperature, high-strength polymer could be loaded with more than 40 percent of the filler without compromising the mechanical properties needed for the Read/Write head trays.
• the surfaces for holding the Read/Write heads were su ⁇ risingly found to be flat, with a flatness that exceeded the flatness obtained with stainless steel fillers.
• Table 1 Mixtures of metal oxide particles with high temperature, high-strength polymer.
• Prototype Read/Write head trays were prepared by molding them from a mixture PEEK and a metal oxide ceramic, as indicated in Table 2.
• the molding process was essentially the same as the process used for PEEK loaded with stainless steel, although the molding temperature was adjusted slightly downwards.
• the results of these experiments showed that metal oxide ceramics could be used to make light colored Read/Write head trays that are ESD safe.
• the high temperature, high-strength polymer could be loaded with more than 40 percent of the filler without compromising the mechanical properties needed for the Read/Write head trays.
• Table 2 ESD properties of mixtures of metal oxide particles with high temperature, high- stren th ol mer.
• the properties of various compositions of PEEK mixed with metal oxide ceramics were compared, as indicated in Table 3, with a carbon fiber composition (18% wt.) and neat mixture of PEEK used as controls.
• Zelec® ECP 1410T (52%) was used as the metal oxide ceramic.
• the molding process was essentially the same as the process used for PEEK loaded with stainless steel, although the molding temperature was adjusted slightly downwards for most compositions.
• Shrinkage in the prototype head trays ranged from 0.008 to 0.013 in in, an acceptable amount. Further, the prototypes were remarkably flat.
• the first prototype head tray model had a surface for receiving a Read/Write head having an average flatness of 0.004 +/- 0.001 in in with a maximum of 0.007 in in.
• a second prototype head tray model had a surface for receiving a Read/Write head that had an average flatness of 0.013 +/- 0.010 in in with a maximum of 0.017 in/in.
• Table 4 Resin purity for various high temperature, high-strength compounds containing metal oxides.
• Table 5 Metal levels of the compositions of Table 4.
• An embodiment of the invention is a read/write head tray, at least a portion of the tray comprising an electrostatic discharge-safe surface for receiving a read/write head, with the surface being made of a mixture of at least one high temperature, high strength polymer and at least one metal oxide.
• Another embodiment of the invention is a tray made with a high temperature, high strength polymer chosen from the group consisting of polyphenylene sulfide, polyetherimide, polyarylketones, polyetherketone, polyetheretherketone, polyetherketoneketone, and polyethersulfone.
• Another embodiment of the invention is a tray wherein the at least one metal oxide is chosen from the group consisting of aluminum borate, zinc oxide, basic magnesium sulfate, magnesium oxide, graphite, potassium titanate, magnesium borate, titanium diboride, tin oxide, calcium sulfate, and antimony doped tin oxide.
• Another embodiment of the invention is a tray wherein the metal oxide is disposed in particles, and the particles are present in the mixture at a concentration of at least 40 percent by weight, or at a concentration of between 50 and 70 percent.
• the particles may also further comprise a ceramic.
• the metal oxide may be disposed in a whisker.
• the whiskers may be chosen from the group consisting of whiskers made of potassium titanate and aluminum borate.
• Another embodiment of the invention is a filler comprising metal oxide disposed in a particle, wherein the particle has an isotropic flow shape.

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