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Patents of interest.

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

Monitoring Injection Molding

U.S. Patent 7,017,412 (March 28, 2006), "Continuous Wave Ultrasonic Process Monitor for Polymer Processing," Charles L. Thomas, Russell Edwards, and Liyong Diao (University of Utah Research Foundation, Salt Lake City, Utah).

Injection molding can be monitored with ultrasonics, but it is expensive, requiring sensitive equipment and a high level of understanding. These problems can be avoided with continuous acoustic energy rather than pulsed energy. Continuous waves are much less complex. In this invention, a continuous resonant frequency is generated and monitored for changes. These changes can be related to the state of the polymer and used to control the injection process. In the given example, a signal generator produced a sine wave to drive a transducer attached to the mold. A resonant frequency is established for the mold and transducer. This resonant frequency can be adjusted with the signal generator. A signal processor monitors the return signal. As the polymer is injected into the cavity, the resonant frequency and amplitude change. This output signal provides the feedback to control the molding process, such as how much and for how long material is injected, when the packing begins, and when to stop injection or packing.

Multilayer Molding

U.S. Patent 7,018,190 (March 28, 2006), "Resin Multilayer Molding Method and Multilayer Molding Device," Akio Okamoto and Etsuo Okahara (Ube Industries, Ltd., Ube, Japan).

Multilayer molding is a way to reduce decorating costs with a single molding process. However, the decorating insert is often damaged by the high temperature and high pressure loading of the core-material during filling. The problem can be avoided by heating the skin material above its glass transition, which enables the skin layer to recover its original state. This is done by first inducing an air-insulating layer between the skin and the mold surface. When the appropriate skin temperature is reached and held for a preset holding time, the mold is closed and the molding cycle is completed. This self-healing process eliminates most of the surface defects.

Polypropylene Branching

U.S. Patent 7,019,044 (March 28, 2006), "Production of Polyolefins Having Improved Properties," Guy Debras, Marc Dupire, and Jacques Michel (Total Petrochemicals Research Feluy, Feluy, Belgium).

Polypropylene resins generally have low melt strengths, restricting their use because of processing difficulties. The melt strength of a metallocene polypropylene having a double-bond concentration of at least 0.1 per 10,000 carbon atoms can be increased by irradiation with a 5-MeV electron beam and a radiation dose of 5 kGray, followed by melting and mechanical processing. The result is long-chain branching. A metallocene catalyst promotes betahydrogen elimination to form unsaturated vinylidene end groups. The electron beam induces free radicals in the chains. When the irradiated polymer is worked in the melt, for example by extrusion, reactions occur between the free radicals and terminal double bonds, forming the long-chain branches without the need for other grafting agents.

Reducing Organohalogens During Incineration

U.S. Patent 7,022,162 (April 4, 2006), "Use of a Material and a Method for Retaining Polyhalogenated Compounds," Siegfried Kreisz and Hans Hunsinger (Forschungszentrum Karlsruhe GmbH, Karlsruhe, Germany).

Polyhalogenated compounds including polychlorinated dibenzo-p-dioxines and dibenzofurans formed during incineration are carried off with the waste gas, contaminating the surrounding environment. These compounds must be removed as early as possible by some flue-gas-purification process, which usually occurs immediately after incineration, using special catalysts such as activated carbon and fabric filters. All these methods result in halogen concentrations well below the legal emission limit, but they are cumbersome and expensive. These problems can be avoided using activated carbon fillers in a polypropylene matrix. During the incineration, the liberated halogen compounds diffuse readily into the polypropylene matrix and are trapped by the activated carbon. The carbon adsorption of halogenated compounds is especially strong. Activated carbon, soot, or finely ground hearth-furnace coke is well suited as a filler particle in a polyolefin matrix. The degree of desorption from the carbon-filled polypropylene is lower than the desorption from the undoped material by a factor of 100 or more.

Self-Repairing Composites

U.S. Patent 7,022,179 (April 4, 2006), "Self-Repairing, Reinforced Matrix Materials," Carolyn M. Dry (Winona, Minnesota).

During use, composites often form microcracks, which can be the site of later catastrophic failures. On the microscopic scale, damage usually involves matrix microcracking with debonding at the fiber/matrix interface. The ability to self-heal would reduce the probability of later catastrophic failure and could even strengthen the material. This patent describes using hollow fibers dispersed in the matrix, which, when broken, release a healing agent. The hollow fibers can be inorganic or organic and of any desired length, wall thickness, or cross-sectional configuration. Healing agents include polymerizable monomers such as methyl methacrylates, styrene, or other polymerizable starting materials. Other agents may be used, such as sealants to prevent water permeability, or adhesives.

A Cheap Way To Make Polyaniline

U.S. Patent 7,022,420 (April 4, 2006), "Assembled Hematin, Method for Forming Same, and Method for Polymerizing Aromatic Monomers Using Same," Ferdinando Bruno, Lynne A. Samuelson, Ramaswamy Nagarajan, Jayant Kumar, and Michael Sennett (U.S. Army, Washington, D.C.).

Synthesizing polyaromatic polymers remains a problem because of inconsistent composition and dangerous, toxic reagents. In addition, the products are insoluble and difficult to process. These problems can be avoided using a heine-containing enzyme to catalyze the polymerization. Hematin is a complex red organic pigment containing iron for binding oxygen. Hemoglobin consists of the protein globin with heine, which gives red blood cells their color and carries oxygen. A hematin catalyst is formed by depositing hematin on an electrically charged substrate in layers alternating with layers of cationic polyelectrolyte. The assembled hematin is contacted with the monomer and an anionic polymer for a template. For aniline, the polymerizing mixture includes aniline, sulfonated multiwalled carbon nanotubes, and polyethylene glycol hematin with a reaction initiator dispersed in water. Polymerization can be carried out in a buffered solution from 0[degree]C to 50[degrees]C. The result is a complex of polyaniline and multiwalled carbon nanotubes, easy to process with exceptional stability.

Cleaning Processing Equipment

U.S. Patent 7,025,070 (April 11, 2006), "Resin Composition for Purging Contaminant in the Plastic Processing Machine," Shigekatu Sato (Kawasaki-City, Japan).

Plastics processing involves hot plastic melts; so, decomposing additives, monomers, and resins often form carbonized residues, which can lead to defective products. Cleaning is time-consuming and expensive, often involving dismantling the equipment and abrasive actions. A resin/borate ester mixture described in this patent can clean equipment without these actions. An effective mixture consists of 100 parts thermoplastic resin and 0.1 to 10 parts borate glycol ether ester. After a run, the processing machine is filled with the purging mixture and the heat is turned off. The machine is cooled to room temperature, and the purging mixture remains in place for 6 to 48 hours to react with the contaminating residues. At the beginning of the next run, the new production resin is fed into the machine and the machine is cleaned automatically.

Joining Polyolefins With Polyamides

U.S. Patent 7,025,843 (April 11, 2006), "Articles Comprising a Polyolefin-Based Element Joined to a Polyamide-Based Element, and Process for Obtaining Them," Nicolangelo Peduto (Rhodia Engineering Plastics, S.A., St. Fons, France).

Because polyamides and polyolefins are chemically incompatible, these materials normally cannot be welded together. However, welding becomes possible with the use of a compatibilizer and a dispersed phase. The polyolefin may be polyethylene, polypropylene, or copolymers of ethylene and alpha-olefins. The second material is a polyamide containing a compatibilizer with a dispersed polyolefin phase. The compatibilizer is an ionomer, (80/10/10) ethylene/isobutyl acrylate/methacrylic acid copolymer, 70% neutralized with zinc. Welding occurs when surfaces are brought into contact and heated to a temperature above their softening points, preferably close to their melting points. The polyamide will have a continuous polyamide phase with a dispersed polyolefin phase. An example of a weldable polyamide consists of 57.4 wt% polyamide, 30 wt% HDPE, and 10 wt% ionomer, with 2.6 wt% pigments and lubricants.

Adhesive Bonding

U.S. Patent 7,025,851 (April 11, 2006) "Contact Metathesis Polymerization," Kenneth C. Caster and Christopher G. Keck (Lord Corp., Cary, North Carolina).

Adhesive bonding can be promoted with a metathesis catalyst on a surface that reacts with the other surface for bonding. This involves two steps: a coating process and an adhesive process. The adhesion is developed by contacting the catalyst on the first surface with a reactive material such as norbomene on the other surface. The metathesis catalysts are transition metal carbene catalysts. A heat-reactive peroxide compound can be included for crosslinking during a post-cure heating step. Candidate materials for gluing are rubber, thermoplastic elastomers, engineering plastics, metals, fibers, and composites. One example is bonding a tire tread to a tire carcass.

Conductive Rubber Foams

U.S. Patent 7,029,722 (April 18, 2006), "Conductive Elastomeric Foams and Method of Manufacture Thereof," Robert A. Weiss, Can Erkey, Suresh L. Shenoy, and Daniel Cohen (University of Connecticut, Storrs, Connecticut).

A conductive polymer composite based on polypyr role and derivatives is manufactured by diffusing an oxidant such as iodine into a polyurethane foam and then diffusing pyrrole vapor into the impregnated foam, resulting in an in-sim chemical oxidative pyrrole polymerization. Supercritical carbon dioxide is used to dissolve the oxidant, swell the polyurethane foam, and incorporate the oxidant. The polymer may also be impregnated by exposure to a vapor of the oxidant, followed by exposure to pyrrole. Polymerization occurs on contact of the pyrrole monomer with the iodine, resulting in an even distribution of the electrically conductive polypyrrole within the polymer.

Roger D. Corneliussen is Professor Emeritus of Materials' Engineering, Drexel University, in Philadelphia. 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 National 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 in Horizons are based on the weekly selection process. To sample Maro Patent Alerts, email a request to cornelrd@bee.net.
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Title Annotation:patents of polymer engineering
Author:Corneliussen, Roger D.
Publication:Plastics Engineering
Geographic Code:1USA
Date:Jun 1, 2006
Words:1747
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