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Foaming Polycarbonates

U.S. Patent 9,259,874 (February 16, 2016), “Polycarbonate Resin Foamed Blow-Molded Article and Process for Producing Same,” Tomoo Tokiwa and Masahiro Gomibuchi (JSP Corp., Tokyo, Japan).

Polycarbonate (PC) resins have very high melt viscosity near their foaming temperature, requiring higher extrusion pressures than other resins such as polystyrene. Even modified PC resins have such a high melt viscosity it’s not possible to form a parison suitable for blow molding.

Tokiwa and Gomibuchi formed, by melting and kneading a branched polycarbonate resin with a blowing agent, a foamable molten resin composition with reasonable viscosity. This material is then extruded to form a foamed parison and then blown to form the foamed structure. The branched PC resin is formed by mixing a linear PC resin with extra hydroxyl groups with a branching agent such as an epoxy acrylic polymer, with epoxy and carboxyl groups reacting with the PC’s hydroxyl groups.

Blowing and Filling

U.S. Patent 9,254,617 (February 9, 2016), “Method and Apparatus for Forming and Filling a Container,” Kirk Edward Maki, George David Lisch, and Bradley Wilson (Discma AG., Hunenberg, Switzerland). 

Traditionally, blow molding and container filling have developed as two independent processes, in many cases operated by different companies at different sites. In order to make bottle filling more cost effective, some companies have moved blow molding in-house, in some cases integrating blow molding directly into their filling lines.

Maki, Lisch, and Wilson developed a system for simultaneously forming and filling a container, with a mold cavity defining an internal surface and adapted to accept a preform. The system includes a servo pressure system controlling the blowing and output fluid. A blow nozzle receives the fluid from the servo pressure source and transfers the fluid into the preform, expanding the preform and forming the container. The fluid remains within the container as the end product. The servo pressure system and the blow nozzle completes the blowing and filling process in less than 0.5 seconds.

Grinding Recycled Plastics

U.S. Patent 9,254,603 (February 9, 2016), “Apparatus for Processing Plastic Material,” Klaus Feichtinger and Manfred Hackl (EREMA Engineering Recycling Maschinen und Anlagen Gesellschaft M.B.H., Ansfelden, Austria).

Mixtures of plastics for recycling can be pulverized and pelletized for processing. One problem concerns efficiently grinding and transferring a mixture to an extruder without premature melting, which plugs and disrupts the process.

Feichtinger and Hackl found that the direction of rotating and grinding, compared to the direction of transferring and extruding, is critical. Reversing the direction of grinding and conveying the powder, compared to the extrusion direction, makes the process more efficient and trouble-free by preventing premature melting. The result is enhanced recycling of mixtures of plastics.

Clean Encapsulation

U.S. Patent 9,254,596 (February 9, 2016), “Top Gate Mold with Particle Trap,” Jerome Teysseyre and Glenn de los Reyes (STMicroelectronics PTE Ltd., Singapore).

Fragile semiconductor devices are encapsulated by injection molding in large numbers. These structures are becoming smaller and smaller, with greater sensitivity to molding conditions as well as melt contamination. Contamination often slows or stops the molding process, and cleaning is slow and difficult.

Teysseyre and de los Reyes developed a top-gate molding system for encapsulating semiconductor devices based on mold cavities formed between a middle plate and a bottom plate with an elaborate runner system. The runners are attached reservoirs inputting to the cavities. A particle trap is placed below the runner to capture contaminating particles during flow into the reservoirs, ensuring a clean resin flowing into the cavities. This particle trap is a notch or a channel across the runners.

Profile Extrusion

U.S. Patent 9,249,289 (February 2, 2016), “1-Butene Copolymers Compositions for Extruded Profiles,” Paolo Ferrari, Luca Lunghi, Roberta Marchini, Stefano Spataro, Giampaolo Pellegatti, Caroline Cathelin, and Stefano Pasquali (Basell Poliolefine Italia S.r.l., Milan, Italy).

Extruded profiles for buildings are often intended to provide self-healing seals against air and water. However, forming self-healing seals is difficult and requires a careful selection of materials.

Ferrari et al. developed extruded or molded self-healing profiles consisting of 85 wt% of 1-butene/ethylene copolymer with up to 18 mol% ethylene content, no detectable melting point, and up to 15 wt% of a propylene copolymer with a melting point of 126 to 200°C. This material can be melt-blended by extrusion and pelletized for molding or further extrusion.

Fuel-Resistant Polyacetal

U.S. Patent 9,249,279 (February 2, 2016), “Fuel Resistant Resin Molded Body,” Akihide Shimoda (Polyplastics Co., Ltd., Tokyo, Japan).

Polyacetal resin is excellent in mechanical, thermal, electrical, friction, and molding properties, and is widely used mainly in electrical devices, automotive parts, and precision machinery components. However, a higher fuel-resistance is necessary for polyacetal applications such as fuel pumps.

Shimoda developed a fuel-resistant polyacetal material containing a moldable polyacetal resin, 0.05 to 1.0 wt% hindered phenol antioxidant, and 0.01 to 2.0 wt% fatty-acid calcium salt. This material can be injection molded, extruded, and blow molded. Testing has reportedly shown dramatic improvement in light oil at 120°C.

Stable Resistivity

U.S. Patent 9,267,048 (February 23, 2016), “Methods to Control Electrical Resistivity in Filler-Polymer Compositions and Products Related Thereto,” Andriy Korchev, Jeremy Huffman, Agathagelos Kyrlidis, Pavel Kossyrev, and Eugene Step (Cabot Corp., Boston, Massachusetts, USA).

Carbon black-filled polymers are used for materials with specific resistivities ranging from 10 to 10¹⁸ ohm-cm. Functionalizing the carbon black enhances conductivity, but this functionalization is degraded by heat. There’s a need for heat-stable electrical resistivity in filled polymer materials.

Korchev et al. stabilized resistivity in these materials with dual-phase fillers. These fillers consist of silica and carbon phases. The conductive composites are filled with 1 to 50 wt% of this dual-phase filler. The filler has a 10 to 90% silica phase content (exposed outer surface area). The carbon black phase consists of non-functionalized crystalline graphite and amorphous carbon. The dual-phase particles are less than 260 nm in size and are stable to 500°C and more. 

Safety-Glass Interlayers

U.S. Patent 9,248,626 (February 2, 2016), “Polymer Interlayers Comprising a Blend of Two or More Resins,” Jun Lu (Solutia Inc., St. Louis, Missouri, USA).

Safety-glass laminates have polymer interlayers for absorbing energy and preventing sharp pieces forming during fracture. But there’s a need for improved acoustic performance, as well as handling and processing performance.

Lu developed an interlayer from a blend of thermoplastic resins with high refractive index and improved acoustic and optical properties. High refractive index plasticizers improve transparency and acoustic properties without sacrificing other necessary properties. The formulation consists of two polyvinylbutyral resins with different hydroxyl contents and a plasticizer so that the refractive index of the polymer interlayer is at least 1.480.

Vibration Damping

U.S. Patent 9,265,999 (February 23, 2016), “Vibration Dampening Material and Method of Making Same,” Robert A. Vito, Carmen N. DiMario, and Thomas Falone (Matscitechno Licensing Co., Kennett Square, Pennsylvania, USA). 

Handles for sporting equipment, bicycles, and hand tools made of wood, metal, or polymers are used to protect the user’s hands during operation. But they transmit vibrations, making prolonged gripping uncomfortable (and dangerous).

Vito, DiMario, and Falone developed polymeric laminates which reduce vibration by distribution and dissipation. The material is based on an elastomer with an embedded support structure. This semi-rigid support is stiff but not inflexible and does not permanently hold its shape when stretched, bent, or twisted.

The material is a mixture of elastomer, filler particles, gel particles, and fibers. The fibers are preferably aramid fibers but can also be bamboo, glass, metal, elastomer, polymer, ceramic, or corn husks. The filler particles are glass, polymer, elastomer, chopped aramid, ceramic, chopped fibers, sand, gel, foam, metal, mineral, or glass beads. Gel particles, such as silicone gel, provide the vibration dampening.