Barrier Film, Functionalized
U.S. Patent 7,666,490 (Feb. 23, 2010), "Functional Roll Film and Vacuum Evaporation Apparatus Capable of Producing the Functional Roll Film," Kiyoshi Iseki, Seiichiro Yokoyama, Takahiro Kubota, Hiroshi Fujita, Tsukasa Ohshima, Shuji Hidaka, Yoshinori Takada, Yozo Yamada, and Shinji Suzuki (Toyo Boseki Kabushiki Kaisha, Osaka, Japan).
A functional roll film is a transparent plastic film with a barrier layer, which is an inorganic oxide layer that can be wound on a roll without cracking. The uniformity and precise thickness of the barrier layer are critical for reproducible, predictable barrier properties. Uniform thickness is difficult to control during fabrication because of problems in monitoring thickness. Using vacuum evaporation, Iseki et al. produced high-quality barrier films in which the thickness is monitored with fluorescent X-ray analysis. The barrier layer can be a mixture of aluminum and magnesium oxides or a semi-metal oxide such as silica. The thickness of the oxide layer is kept between 10 and 50 nm; the polymer film can be a polyolefin, polyester, polyamide, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyimide, polysulfone, polyphenylene sulfide, or polyphenylene oxide.
U.S. Patent 7,666,494 (Feb. 23, 2010), "Microporous Article Having Metallic Nanoparticle Coating," Donald J. McClure and Mario A. Perez (3M Innovative Properties Co., St. Paul, Minnesota, USA).
Metallic nanoparticles, 1 to 100 nm, have important uses in semiconductors, magnetic storage, electronics, and catalysis. These nanoparticles show unique optical properties such as optical resonance resulting from the collective coupling of the conduction electrons in the metal sphere to the incident radiation. The result is absorption or scattering, depending on the nanoparticle size and the radiation wavelength. A variety of devices are based on optical resonance, such as optical filters or chemical sensors using surface-enhanced Raman scattering. McClure and Perez have developed a microporous material with a metallic nanoparticle coating. The nanoparticle coating is formed by vapor deposition, resulting in 1- to 50-nm nanoparticles in a 10-nm coating or less. The foam base has a network of connected 1000-nm to 4-micron pores. The foam is formed by solidification of a polymer solution, followed by solvent extraction. A variety of metals can be used, but noble metals are preferred.
Expanded PTFE Structures
U.S. Patent 7,666,496 (Feb. 23, 2010), "Micro-Sintered Node ePTFE Structure," Julio Duran (Boston Scientific Scimed, Inc., Maple Grove, Minnesota, USA).
Expanded polytetrafluoroethylene (ePTFE) structures are used as vascular, esophageal, urethral, and enteral prostheses because of the biocompatibility of ePTFE. Unfortunately, ePTFE tubes tend to kink during bending. Kinking and luminal constriction can occur during or after implantation, seriously affecting function. Multiaxial expansion of ePTFE materials produces a random structure of nodes and fibrils. Duran was able to stiffen these structures by annealing and causing some of the nodes to attach to fibrils, effectively crosslinking the microstructure. During annealing, the nodes are sintered, while the fibrils are not. The material is strengthened and stiffened by regions with the sintered nodes. Regions with un-sintered nodes and fibrils remain more fexible, providing some pliability. This material is microsintered to form the final reinforced structure. The sintering occurs during heating of all or portions of the regions with nodes from 600[degrees]F to 670[degrees]F for up to 20 minutes. The sintering is sufficiently limited so that some of the nodes remain un-sintered.
U.S. Patent 7,666,503 (Feb. 23, 2010), "Self-Healing Cables," Mark R. Easter (General Cable Technologies Corp., Highland Heights, Kentucky, USA).
Cables for power transmission and telecommunication based on stranded or solid conductors with polymer insulation have been used for many years. The conductors are aluminum or copper; aluminum is preferred because of its lighter weight and lower cost. These cables may be damaged during or after installation, especially when buried, installed in tunnels or inside buried pipes. Cracking of the outer sheath may lead to cracking of the insulation and moisture infiltration, resulting in leakage currents and conductor corrosion. Easter of General Cable Technologies has developed a self-healing cable based on a conductor insulated with a composite containing water-swellable fillers. When water reaches the exposed insulation, the filler expands and fills the voids, punctures, or cracks, sealing the damaged insulation. The polymeric carrier can be petroleum jelly, polyisobutene, polyisoprene, natural terpolymers, propylene/ethylene copolymers, polyolefins, or amorphous ethylene copolymers with unsaturated esters. The water-swellable fillers can be bentonite, lignite, alumina trihydrate, barytes, calcium carbonate, chlorite, clays, pyrophyllite, talc, polyacrylic acid, polyacrylamide, sodium polyacrylate, cellulose esters, ethylene vinyl chloride, acrylic resins, alkyd resins, polyethylene oxide, collagens, gelatins, or ethylene acrylic acid copolymers. Of these, sodium bentonite and polyethylene oxide are preferred. The composites contain enough water-swellable fliers to cause 15% to 150% swelling.
U.S. Patent 7,669,791 (Mar. 2, 2010), "Method and Device for Producing Highly Active Rubber Powder From Rubber Wastes," Vladimir Balyberdin and Roudolf Gorelik (Deutsche Gumtec AG, Halle, Germany).
Scrap tires and rubber waste are pulverized by impact at low temperatures using various types of crushers. However, these wastes do not produce rubber powders with a specific surface area high enough for chemical activity. The specific surface area of a powder with a particle size of 20 microns does not exceed 0.12 m2/g. Balyberdin and Gorelik produced active rubber powder with a specific surface area of 0.4 to 5.0 m2/g from scrap tires and vulcanized waste rubber, including butadiene, butadiene styrene, and butadiene nitrile rubbers, and from hydrogenated, carboxylated ethylene, propylene, fluorine, fluorosilicone, vinyl pyridine, silicone, epichlorohydrin, polychloroprene, polyisobutylene, and acrylic rubbers. They used an extruder and thermomechanical action, and they used two stages; one with a volume stress of 15 to 150 MPa, increasing at a rate of 5 to 90 MPa/s with an amplitude of [+ or -] 0.5 to 20 MPa and pulsating at a frequency of 5 to 500 Hz, and one with a temperature of 90[degrees]C to 380[degrees]C. The comminution initially generates partide porosity. During stress reduction, the porosity disappears, but the specific surface area of the rubber particles increases and the rubber particles are cooled.
Biodegradable FlameRetardant Polymer
U.S. Patent 7,666,922 (Feb[degrees] 23, 2010), "Flame-Retardant Biodegradable Material and Manufacturing Method of the Same, Flame-Retardant Biodegradable Polymeric Composition, and Molded Product and Disposal Method of the Same," Kenji Yao (Fuji Xerox Co., Ltd., Tokyo, Japan).
Biodegradable polymers are decomposed into water and carbon dioxide through hydrolysis by microorganisms existing in soil or water. In general, biodegradable polymers are poor in mechanical strength and heat resistance. In order to overcome these defects, natural fillers such as mica have been added. Often these materials must also be fire-resistant. Unfortunately, most flame retardants are not biodegradable, and they are often toxic to microorganisms. Yao has developed a silicone polyester block copolymer that is both biodegradable and flame-retardant. The polymers consist of chains of AB silicone/aliphatic polyester blocks. This flame-retardant biodegradable resin is compatible with other biodegradable resins, making the copolymer a flame-retardant additive that does not affect biodegradability. In one example, three parts by weight were added to 97 parts of poly(lactic acid). The sample showed slightly enhanced biodegradability, and it eliminated the formation of dripping residues during combustion with increased tensile and impact strength.
U.S. Patent 7,674,410 (Mar. 9, 2010), "Method for Manufacturing a Thermal Interface Material," Hua Huang, Yang Wu, Chang-Hong Liu, and Shou-Shan Fan (Tsinghua University, Beijing, China, and Hon Hai Precision Industry Co., Ltd., Tu-Cheng, Taipei Hsien, Taiwan).
As electronic components become smaller, heat-dissipation requirements increase. A heat sink is used between electronic components to efficiently dissipate heat generated during operation. Conventional heat sinks are composites filled with thermally conductive particles. Such particles include graphite, boron nitride, silicon oxide, alumina, silver, and other metals. However, the heat conduction of most composites is too low for many contemporary applications. The thermal conductivity of a carbon nanotube is very high, but carbon nanotube heat sinks are not satisfactory, probably because of interface resistances. Huang et al. have developed an effective heat sink based on a carbon nanotube array anchored in a phase-change material. As the exposed nanotubes are heated, the heat flows to the phase-change material, which quickly absorbs the energy through the phase change. Such phase-change materials include paraffin, polyolefins, low-molecular-weight polyesters, low-molecular-weight epoxies, and low-molecular-weight acrylics. The composite shows very low thermal resistance for both high and low heat fluxes.
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 send the links daily to subscribers. These patent abstracts are based on the weekly selection process. To sample Maro Patent Alerts, email a request to email@example.com.
The patents described here are selected on the basis of their novelty; selection does not affirm or imply the accuracy of a patent or its practical applicability.
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|Date:||Jun 1, 2010|
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