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Molding Microcellular Materials

U.S. Patent 9,555,564 Uan. 31, 20 17), "Method of Fabricating a Foamed, Injection Molded Component with Improved Ductility and Toughness," Lih-Sheng Turng and Xiaofei Sun (Wisconsin Alumni Research Foundation, Madison, Wis.).

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Plastics have greatly improved our quality of life but the rising cost of fossil-based plastics and their environmental burden is a problem. Microcellular injection molding can produce foamed parts with many advantages, including reduced cost, lower weight and recyclability. However, microcellular materials have poor ductility and toughness. Turng and Sun have developed cost-effective, micro-foamed plastics by injection molding. Plasticizing pellets of two different resins and a supercritical fluid are injection molded, forming two immiscible phases with microcellular voids. After molding, tensile loading leads to submicron microcellular voids within the dispersed phase domains. These void mixtures lead to improved ductility and toughness. Example resins are polypropylene/high density polyethylene blends with supercritical carbon dioxide.

Overmolding Reinforcements

U.S. Patent 9,555,569 (jan. 31, 2017). "Plastic Overmolding of Aluminum Extrusions," Mark Peter Birka (Magna Exteriors Inc., Concord, Ontario, Canada).

Aluminum structures such as hollow tubes are often inserted in plastics for strength and stiffness. During molding, steel mandrels are inserted to prevent crushing aluminum structures under pressures of 12,000 to 20,000 psi. There is a need for plastic overmolding aluminum extrusions without mandrels. Birka used aluminum extrusions with internal stiffening structures to prevent collapsing under injection or compression molding pressures. This improves part geometry and strength while minimizing weight. In addition, external protrusions and interface deformations enable strong connections with the plastic matrix. These aluminum extrusions are compatible fiber-reinforced plastics, short glass fiber-reinforced nylons, thermoplastic polyolefins and other suitable plastics.

Blow Molding Lined Containers

U.S. Patent 9,555,572 (Jan. 31, 20 17), "Integrally Blow Molded Bag-in-Container Comprising an Inner Layer and an Outer Layer Comprising Energy-Absorbing Additives, Preform for Making It and Process for Producing It," Sarah Van Hove, Daniel Peirsman and Rudi Verpoorten (Anheuser-Busch InBev SA, Brussels, Belgium).

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Bag-in-containers are used for liquid dispensing packages consisting of a container with a collapsible inner bag. Usually such containers are produced separately and assembled later. This makes them expensive and labor-intensive. Van Hove, Peirsman and Verpoorten developed a system for blow molding bag-in-containers using a single preform. This preform consists of a two-layer structure for blow molding. The inner layer is released from the outer layer after blowing by injecting a gas in the interface between the two layers. Additives are used to enable both inner and outer layers to reach their respective blow molding temperatures at the same time. Candidate resins include polyesters, polyamides and polyolefins. Energy-absorbing additives include carbon and sulfonium salts.

30 Printing with Multiple Materials

U.S. Patent 9,561,623 (Feb. 7, 2017), "Method and Apparatus for Making Three-Dimensional Objects from Multiple Solidifiable Materials," Ali EI-Siblani and Alexandr Shkolnik (Global Filtration Systems, Dearborn Heights, Mich.).

In 3D printing it is sometimes desirable to use several different materials in the final product. EI-Siblani and Shkolnik developed a 3D printing device with several containers that hold different materials. The printer moves to different containers as needed during fabrication. This device also uses a cleaning step for removing residues from the surfaces during fabrication to ensure smooth and sharp transitions between the different materials in the finished object. Candidate fabrication materials include acrylic, epoxies, fillers, colorants and other additives.

Epoxies for Recycling

U.S. Patent 9,562,132 (Feb. 7, 2017), "Hot-Formable and Recyclable Epoxy Anhydride Thermosetting Resins and Thermosetting Composites," Ludwik Lei bier, Francois Tournilhac, Damien Montarnal and Mathieu Capelot (Centre National De La Recherche Scientifique, Paris, France, and Arkema France, Colombes, France).

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Thermosetting resins are molded and crosslinked to form a permanent structure. Processing often involves liquids requiring precise manipulations and metering. Manufacturing with liquids can be messy and even dangerous. In addition, molding must be precise since the results cannot be easily corrected or recycled. Lei bier et al developed thermosetting resins that are hot-formable, repairable and even recyclable. Examples are epoxies with hydroxy and epoxy groups with acid anhydride groups and transesterification catalysts. These materials are partially cured for thermoplastic-like processing. They are, then, molded and cured to form rigid, high-temperature materials. The material has many excess free hydroxyl groups that remain even after the final curing for repair and recycling. The total molar quantity of the transesterification catalyst is between 5 and 25% of the hydroxyl and epoxy content in the thermosetting resin precursor.

Thermosetting resins are molded and crosslinked to form a permanent structure. Processing often involves liquids requiring precise manipulations and metering. Manufacturing with liquids can be messy and even dangerous. In addition, molding must be precise since the results cannot be easily corrected or recycled. Lei bier et al developed thermosetting resins that are hot-formable, repairable and even recyclable. Examples are epoxies with hydroxy and epoxy groups with acid anhydride groups and transesterification catalysts. These materials are partially cured for thermoplastic-like processing. They are, then, molded and cured to form rigid, high-temperature materials. The material has many excess free hydroxyl groups that remain even after the final curing for repair and recycling. The total molar quantity of the transesterification catalyst is between 5 and 25% of the hydroxyl and epoxy content in the thermosetting resin precursor.

U.S. Patent 9,566,720 (Feb. 14, 20 17), "Apparatus for the Pretreatment and Subsequent Conveying, Plastification, or Agglomeration of Plastics, " Klaus Feichtinger and Manfred Hackl (Erema Engineering Recycling Maschinen und Anlagen Gesellschaft MBH, Ansfelden, Austria).

Recycling plastics requires grinding, pretreatment and extrusion. The recycled plastic is treated with additives, followed by grinding and pelletizing by extrusion for further processing into useful products. The coordination between grinding is difficult and troublesome. Feichtinger and Hackl prepared recycled plastics by automated, coordinated grinding and pelletizing. This consists of a container with a rotating mixing, heating and comminution device sending the mixture into a multi-screw extruder with at least two rotating screws for pelletizing. The problem is erratic flow into the extruder by the grinding device. Changing the flow of the grinding process to a flow in a direction different from the exiting extruder flow improved extruder entry. In addition, the material entering the extruder must be softened but not melted. The result of the different flow directions is that the filling of the exiting screw can be adjusted with precision leading to improved product consistency and efficiency making the process cost effective.

Injection Molding Controls

U.S. Patent 9,566, 735 (Feb. 14, 201 7), "Method for Regulating an lnjection Molding Process," Istvan Denes, Paeivi Lehtonen-Brenner, Robert Wieland, Stephan Geise, Guenter Haag, Philipp Liedl, Patricia Maris-Haug, )ens Ackermann, Holger Nalop and Stephan Althaus (Robert Bosch GmbH, Stuttgart, Germany).

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The injection molding process is probably the most common and important method for forming plastic structures. Process control is critical to reliability and product consistency. Quality-monitoring measures are based on machine properties integrated into injection molding machine controls for improved consistency and productivity. Despite this improvement, production parts still may vary and result in defective parts, often requiring a complete shut-down. Denes et al developed a method for regulating an injection molding process using a regulating module based on data from machine sensors and data from the exiting molded parts. In addition, defective parts can be detected and removed as scrap without shutting down the machine.

Injection Molding Surfboards

U.S. Patent 9,566,729 (Feb. 14, 2017), "Injection Molded Surfboard Insert having Pre-Impregnated Composite Fiber Matrix Structure," Vince Longo, Tony Longo and john Griffin (Todos Santos Surf Inc., Huntington Beach, Calif).

Most surfboards, and other water sports boards have one or more fins coupled to the board for stability and control. Properly attaching the fins is difficult, making molding ineffective. Longo, Longo and Griffin developed a prepreg insert for injection molding a water sports board. The insert consists of a board with prep reg fins as an integral, continuous part of the structure. In addition, this prep reg fin improves the strength-to-weight ratio when compared to conventional after-molding assembly with separate joining structures.

Sulfur Composites

U.S. Patent 9,567,439 (Feb. 14, 2017), "Sulfur Composites and Polymeric Materials from Elemental Sulfur," Dong-Chul Pyun, Richard S. Glass and M. Bonner Denton (University of Arizona, Tucson, Ariz.).

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Millions of tons of elemental sulfur are generated as a waste byproduct from hydrodesulfurization of crude petroleum feedstocks stored in megaton-sized, sulfur towers. Elemental sulfur is a brittle, intractable, crystalline solid. Hence, there is a need for new materials that use and remove this solid waste. Pyun, Glass and Denton developed sulfur composites and polymeric materials having a high sulfur content using elemental sulfur as the primary chemical feedstock. Sulfur copolymers are prepared by the polymerization of elemental sulfur with one or more monomers of amines, thiols, sulfides, unsaturated monomers, nitrones, aldehydes, ketones, thiiranes or epoxides. These sulfur copolymers may be further dispersed with metal or ceramic composites or copolymerized with carbon, photoactive organic chromophores or other biocompatible groups. These sulfur composites often show self-healing through thermal reformation. Applications include electrochemical cells, optics, hydrogen sulfide donors and antimicrobial materials.

Recycling Unsorted Plastics

U.S. Patent 9,566,736 (Feb. 14, 2017), "System and Method for Producing Plastic Products from Recycled Mixed Plastic Waste and Plastic Product," Andrus Valdmaa, Aivo Kasnar and A arne Saarevali (Rolan Investment OU, Tal/in, Estonia).

Plastic-waste recycling usually involves sorting, cleaning, grinding and pelletizing for further processing. This process is expensive and time-consuming. Mixed plastic waste that is not easy to sort is often not recycled and instead is either incinerated or landfilled. Valdmaa, Kasnar and Saarevali produced plastic products from a mix of unidentified, unclean and unsorted mixed plastic waste. The recycled plastic waste is melted, mixed with additives and foamed by continuous extrusion and, then, pultruded into strands which are stretched and pelletized .

Lightweight Materials

U.S. Patent 9,567,255 (Feb. 14, 20 17), "Light Weight Structural Materials," William Brenden Carlson, Gregory D. Phelan, Vincenzo Casasanta, Ill and Feng Wan (Empire Technology Development LLC, Wilmington, Del.).

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Consumers and manufacturers for many reasons want lighter-weight products with improved quality and durability. These products must be impact-, crack-, rupture-, fatigue-and corrosion -resistant, as well as formable, transparent, non-toxic, inexpensive to fabricate, manufactured with low environment impact, and biodegradable. Carlson et al used functionalized microspheres stable dispersions for reduced density and weight. These microspheres may be formed from ceramics, glass, metals, carbon and polymers. One example is polyethylene 50-micron microspheres with 5- to 1 O-micron wall thickness. Bonding agents are used to attach functional groups to the microspheres. In one example, the anchoring component is trimethoxysilyl, where the linking component may be a pentyl group and the functional group may be an epoxy group. Polyethylene or polypropylene microspheres are treated with a plasma to form surface hydroxyl groups. These spheres then can be treated with isocyanates to fo rm super-lightweight composites. A 30-micron microsphere may have as many as 400,000 functional units per sphere.

Super-Insulation Materials

U.S. Patent 9,567,412 (Feb. 14, 2017), "Superinsulation with Nanopores," Arthur j. Yang (Industrial Science & Technology Network Inc., Lancaster, Pa.).

Thermal insulation is critically important in many applications, such as buildings, refrigeration and industry. Of special interest is super-insulation based on nanoporosity with cost-effective methods for manufacturing. Yang developed superinsulation articles based on oriented porosity incorporating nanopores. The material needs a minimum porosity, reduced pore size and cost-effective manufacturing. These structures are created by batch depressurization during foam extrusion and structure formation aided by fillers such as exfoliated clay fillers. The process consists of mixing a mixture of material and blowing agent under pressure in an extruder, cooled and injected into a mold followed by batch depressurization. his results in an oriented foam of 20% to 90% porosity with more than 25% of the pores less than 1,500 nm in their shortest diameters.

By Roger Corneliussen

ABOUT THE AUTHOR

Dr. Roger Corneliussen is Professor Emeritus of Materials Engineering of Drexel University in Philadelphia. He has been an SPE member since 1962 and an active member of the Philadelphia Section, serving as president and national councilman for several years. The above patents are selected from the 100 to 400 plasticsrelated patents found by reviewing 3,000 to 7,000 U.S. patents published each Tuesday. Readers can review the complete list of plastics-related patents by week at www.plasticspatents com.

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Title Annotation:INDUSTRY PATENTS
Author:Corneliussen, Roger
Publication:Plastics Engineering
Geographic Code:1USA
Date:May 1, 2017
Words:2067
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