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Industry patents: the patent is a legal document giving the holder a license to capitalize on the invention without competition for a few years. In exchange, the holder teaches the basis of the invention. The patent is forward-looking, representing a technical horizon.

Ceramic/Polymer Composites

U.S. Patent 7,290,586 (November 6, 2007), "Bicontinuous Composites," Rodney Martin Sambrook (Dytech Corp. Ltd., Sheffield, Great Britain).

Sambrook has developed a three-dimensional composite based on an open-cell-ceramic foam filled with metal or polymer for extreme applications. Fabrication begins with a ceramic foam with an interconnected 10% to 30% porosity and 20- to 800-micron pores; the foam is formed by low-pressure extrusion of ceramic particles. These include alumina, zircon, spinel, silicon carbide, tin oxide, hydroxyapatite, zirconia, kyanite, and cordierite. This foam is then impregnated with molten metal or resins using incipient wetness, simple impregnation, or vacuum impregnation. A degradable intermediate may also be used to further control the structure of the interpenetrating components. The metal phase may be aluminum, ferrous, copper, or magnesium alloys. The polymers may be polyethylenes, acrylates, methacrylares, polyesters, or polyanhydrides. The viscosity of the resin must enable easy penetration of the preformed ceramic. Applications include disc brakes with outstanding friction and wear properties.

Wear-Resistant Molds

U.S. Patent 7,290,751 (November 6, 2007), "Composite Mold and Method for Manufacturing the Same," GaLane Chen (Hon Hai Precision Industry Co., Ltd., Tu-Cheng, Taipei Hsien, Taiwan).

Many electronic components in mobile phones, digital cameras, liquid crystal displays, DVD players, and so on, are molded. Used thousands of times, the molds are subject to wear, scratching, and even cracking. Thus the need exists for tougher, more wear-resistant molds. Chen has developed a mold with a protective layer of diamond-like carbon. The mold includes a main mold body and a molding layer. The main body is stainless steel, to avoid corrosion, and the molding layer is a nickel-phosphorus alloy. The molding layer is applied by chemical plating, and the diamond-like coating is applied by sputtering by means of direct current, reactive alternating current, or reactive radio-frequency. A mixture of inert gas, such as argon or krypton, and a reactive gas, such as methane, ethane, or ethyne with a hydrogen-nitrogen mixture, is used in the sputtering process. The resulting mold is very tough and scratch-resistant, and can be used to manufacture products by press molding or injection molding.

Electro-active Eyeglasses

U.S. Patent 7,290,876 (November 6, 2007), "Method and System for Electro-Active Spectacle Lens Design," Dwight F. Duston and William Kokonaski (E-Vision, LLC, Roanoke, Virginia, USA).

Tiny electro-active electrodes can be used to develop eyeglasses with multipie focal lengths at different sites in the lens that can be changed by applied electric fields. Patterned circular electrodes are used to create zones in the lens of varying refractions. Higher-order aberrations require many such electrodes closely packed for the arbitrary patterns needed for wave-front correction. These small electrodes are similar to the picture elements or pixels in a display panel and may include hundreds or thousands of pixels, each individually addressable with a distinct voltage affecting a local point of refractive index. However, the required number of pixels has not been determined. Duston and Kokonaski estimate this number by calculating the number of piston-like pixels necessary to provide a smooth surface. In one example, a 10-mm electro-active zone should have 1150, 6800, and 29,000 pixels for pixel sizes 250, 100, and 50 microns. The number of pixels for a 15-mm electroactive lens to correct for higher-order aberrations is between 2600 and 16,200 pixels, with a pixel size between 250 and 100 microns.

Micro-Encapsulation

U.S. Patent 7,291,296 (November 6, 2007), "Method for Making Very Fine Particles Consisting of a Principle Inserted in a Host Molecule," Michel Perrut, Jennifer Jung, Fabrice Leboeuf, and Isabelle Fabing (Separex, Champigneulles, France).

Micro-encapsulation is very promising for controlled administration of drugs. Many methods have been tried for encapsulation, but more efficient and reproducible methods are still needed. One carrier of great promise is the cyclodextrin formed by the enzymatic degradation of starch. It is a natural biodegradable host whose cyclic form allows capture of a variety of active molecules. Perrut et al. use a supercritical pressure fluid such as carbon dioxide for encapsulation. This makes possible the capture of active agents that are slightly soluble in water or need other organic solvents for encapsulation. Active-ingredient saturation of the supercritical pressure fluid is done by percolation through a particle bed. The particles are then made by atomizing supercritical carbon dioxide solutions of the active agent with similar solutions of cyclodextrin. By this method, a powder of very fine particles was formed by spraying a solution containing 0.32 wt% of the steroid prednisolone and 2.5 wt% methyl-beta-cyclodextrin.

Nanothermometer

U.S. Patent 7,291,299 (November 6, 2007), "Nanotube, Nanothermometer and Method for Producing the Same," Yoshio Bando, Yihua Gao, and Tadao Sato (National Institute for Materials Science, Ibaraki, Japan).

Although there are many thermometers for macroscopic studies, a nanothermometer is needed. Bando et al. have built one by filling carbon nanotubes with continuous columns of gallium that change in length with changes in temperature. These nanothermometers are 1 to 10 microns long with diameters of 40 to 150 nm. They can measure temperatures from 50[degrees]C to 500[degrees]C to within 0.25[degrees]C. The thermometers are made by mixing Ga203 and carbon powders. The carbon powder is an amorphous active carbon and the inert gas is nitrogen. The mixture is heat-treated for 1 hour or more at 1300[degrees]C to 1400[degrees]C. The gallium has a potential measuring range of 30[degrees]C to 2400[degrees]C. The length change is linear from 50[degrees]C to 500[degrees]C, which was confirmed by transmission electron microscopy.

Collapsible Cores

U.S. Patent 7,293,341 (November 13, 2007), "Collapsible-Core Assembly for a Molding Apparatus," Garry Zydron (Progressive Components International Corp., Wauconda, Illinois, USA).

Many injection molds produce parts with details such as internal threads, undercuts, protrusions, or cutouts that include collapsible cores. Unfortunately, these cores are expensive and difficult to manufacture. Zydron has developed a collapsible core based on two ribbed sleeves around an expansion core. The ribs are tapered to provide a continuous surface when expanded. After molding, the central pin is removed, collapsing the inner and outer sleeves, permitting removal. The design is based on standard, interchangeable center pins and collars, eliminating the necessity of mating pins to manufactured cores. The use of separate inner and outer sleeves reduces manufacturing complexities and allows for more precise manufacturing tolerances and interchangeable components, thus reducing costs.

Compensating Molds

U.S. Patent 7,293,981 (November 13, 2007), "Apparatus for Injection Molding Using Active Material Elements," Joachim Johannes Niewels (Husky Injection Molding Systems Ltd., Canada).

Shrinkage of a hardening melt in a mold continues to be a serious problem. The key is maintaining pressure during cooling. Niewels has developed a method for compressing the melt and compensating for melt shrinkage in an injection mold by means of a movable plate. A mold cavity is formed between the mold components with piezoceramic actuators and a cavity plate. A controller connected to the actuators controls the movable plate. This system was used to mold PET performs, and melt compression was continued while compensating for

Surface Treatments

U.S. Patent 7,294,673 (November 13, 2007), "Method of Modifying Polymeric Material and Use Thereof," Hitoshi Kanazawa (FiberMark Gessner GmbH & Co., Feldkirchen-Westerham, Germany).

Many applications, especially those involving polyolefins, require surface treatments. Unfortunately, these treatments often weaken the material and are inadequate. Kanazawa has developed a treatment based on washing, impregnating 0.1 to 40 wt% of the polymer within 1000 microns of the surface, and activating the porous surfaces with carbonyl groups, followed by grafting. The resulting materials are useful for cleaning, water absorption, water retention, medical and sanitary materials, clothing, filters, microbial culture mediums, dental materials, writing materials, medical instruments, fibers for composites, synthetic paper, hydrophilic films, and battery separators. For the battery separators, the materials were washed with toluene, alcohol, or soap solution with alcohol. The surfaces were swollen with a solvent and dried. Carbonyl groups were introduced by a plasma treatment, an ozone treatment, an ultraviolet-light irradiation, a corona discharge, or a high-voltage electric discharge. Monomers for grafting such as vinyl compounds were added depending on the application. Initiators were also added, and grafting was induced by heating or UV irradiation.

Roger D. Corneliussen is Professor Emeritus of Materials Engineering, Drexel University, in Philadelphia, Pennsylvania, USA. He is editor of Maro Polymer Alerts and the Maro Polymer website (www.maropolymeronline.com). He has been active in SPE since 1962 and has served on the board of the Philadelphia Section and as SPE Councilor. For Maro Patent Alerts he reviews all U.S. Patents weekly, makes links to the polymer-related patents, and sends the links daily to subscribers. These patent abstracts are based on the weekly selection process. To sample Maro Patent Alerts, email a request to cornelrd@bee.net.
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Comment:Industry patents: the patent is a legal document giving the holder a license to capitalize on the invention without competition for a few years.
Author:Corneliussen, Roger
Publication:Plastics Engineering
Geographic Code:1USA
Date:Feb 1, 2008
Words:1467
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