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Our Regular Roundup of Notable Patents.

Porous Surfaces

U.S. Patent 10,405,962 (Sept. 10, 2019), "Porous Devices and Methods of Producing the same," Wei-Hsiang Chang, Stephen Lee Laffoon, Christopher S. D. Lee, and David Lee Safranski (Vertera, Inc., Atlanta)

Polymers are useful in many devices. However, sometimes surface porosity is desired but difficult to produce. Chang et al. have produced surface porosity by heating a polymeric surface to a temperature below the melting point but softened. Sodium chloride grains are then pressed into the surface layer and the surface with the grains deformed or sheared. The grains are then removed by leaching and the material cooled to room temperature, leaving a porous surface. The example was polyetheretherketone (PEEK).

Additive Processing

U.S. Patent 10,406,726 (Sept. 10, 2019), "Thixotropic, Thermosetting Resins for Use in a Material Extrusion Process in Additive Manufacturing," Irving D. Sand (Georgia-Pacific Chemicals LLC, Atlanta)

Additive processing is an effective fabrication but is limited to a few useful resins. Sand developed a three-dimensional structure by extruding beads of thixotropic thermosets and curing to form a crosslinked structure. In some cases, the curing doesn't occur until multiple beads are extruded and in contact with one another. The steps can be repeated as desired to prepare a three-dimensional structure with nearly limitless shape.

Coextrusion

U.S. Patent 10,390,979 (Aug. 27, 2019), "Manufacturing

Process for Polymeric Stents," David C. Gale, Bin Huang, Anthony J. Abhate, Timothy A Limon, and Klaus Kleine (Advanced Cardiovascular Systems, Inc., Santa Clara, Calif.)

Plastics are used for packaging but packages sticking together during storage remains a problem. Stroeks, Chen, and Miller developed a coextruded film consisting of low-density polyethylene with a skin layer of a copolyimide with at least 75 wt% caprolactam monomeric units, 5 to 25 wt% diamine and terephthalic acid units. This skin layer may need a tie layer such as modified polyolefins. Sometimes, these coextruded films may consist of several tie layers to improve adhesion.

Blow Molding Fuel Tanks

U.S. Patent 10,408,382 (Sept. 10, 2019), "Extrusion-Blow-Molded Fuel Tank of Thermoplastic Material and Method for the Production thereof," Markus Hutzen, Ulrich Karsch, and Christoph Mehren (Kautex Textron GmbH & Co., KG, Bonn, Germany)

Manufacturing plastic fuel tanks is usually an involved process involving laminates. Delamination can be a problem during shaping a complex shape. In the process, swelling of the inner shell must be considered while ensuring adequate venting. Hutzen, Karsch, and Mehren developed an extrusion-blow-molded fuel tank consisting of several layers produced by different production operations. A first layer of a shell and a second layer of a thermoplastic material forms an adhesive bond with the supporting shell. This supporting shell will have a greater strength than the second layer. The supporting shell forms an inner layer of the tank and the second layer will be the outer skin of the tank.

Oil Sorbents

U.S. Patent 10,413,882 (Sept. 17, 2019), "Polypropylene, Polyester, Newspaper print, and Vermiculite Sorbent," Druv Vohra (Naperville, III.)

Oil spills require cheaper, more efficient sorbents. Vohra found that a combination of polypropylene, polyester, reclaimed newspaper print, and vermiculite makes a very effective filler for a sorbent. It is concluded after many trials that a composition of 48.63 percent polypropylene, 27.97 percent polyester, 1 2.53 percent newspaper print, and 10.87 percent vermiculite in a sorbent absorbs the most oil and repels the most water.

A Better Glove

U.S. Patent 10,414,112 (Sept. 17,2019), "Process for Making an Elastomeric Glove," Timothy M. Lipinski and Choong Kheng Tang (O&M Halyard, Inc., Mechanicsville, Va.)

Plastics in medical gloves must limit exposure of patients to infectious matter and protect health professionals from disease transmission through contact with body fluids. Lipinski and Kheng developed a nitrile-rubber medical exam glove consisting of a flexible layer of nitrile-butadiene rubber combined with protective layers. The glove body has a chlorinated surface on the donning side of the glove body and an un-chlorinated second surface forming a grip side of the glove body. The elastomeric glove also includes a substantially uniform distribution of a release agent distributed over the un-chlorinated second surface of the glove body. The glove body has a chlorinated first surface forming a donning side of the glove body and an un-chlorinated second surface forming a grip side of the glove body. The elastomeric glove has an average thickness of 0.03 to 0.12 mm in the palm with un-chlorinated second surface of the glove body.

Improved Mixing

U.S. Patent 10,414,081 (Sept. 17, 2019), "Multi-Shaft Extruder," Josef A. Blach (Blach Verwaltungs GmbH & Co. KG, (Lauffen am Neckar, Germany)

The mixing and dispersion efficiency of multi-shaft extruders needs improvement. Blach developed a multi-shaft extruder for the processing of free-flowing material with one to three co-rotating, tightly intermeshing conveyor shafts. The conveyor shafts are arranged in an offset manner relative to each other. The conveyor shaft is arranged between two other conveyor shafts with the free-flowing material on its flanks by means of the gap-forming ridges of the two adjacent conveyor shafts.

Foam Processing

U.S. Patent 10,421,227 (Sept. 24, 2019), "Shim-Stack Foaming Die," Jeffrey P. Kalish, James M. Jonza, William J. Kopecky, and Bryan C. Feisel (3M Innovative Properties Co., St. Paul, Minn.)

Conventional extrusion dies are not able to adequately produce foams. Kalish et al. developed shim stack foaming die for making foam slabs consisting of shims that are layered together under pressure to form a stack. These shims form the main body of the shim stack foaming die. Articles foamed from the shim stack foaming die have found wide use in various applications including thermal or acoustic insulation, reinforcing, and space-filling layers.

Foams for Shoes

U.S. Patent 10,421,221 (Sept. 24, 2019), "Process for Foaming Thermoplastic Elastomers," Hossein A Baghdad'!, Yihua Chang, Charles R. Edwards, and Richard L. Watkins (Portland, Ore.)

Polyurethane foams are used in shoes, but a need remains for improved methods of forming foams that can be customized for cushioning in footwear and protective wear. Baghdadi et al. developed a foamed article by infusing the article of thermoplastic elastomer with a supercritical fluid. The article is then removed from the supercritical fluid and immersed in a heated fluid. The article can instead be irradiated with infrared or microwave radiation.

Superhydrophobic Surfaces

U.S. Patent 10,427,331 (Oct. 1, 2019). "Scalable Manufacturing of Superhydrophobic Structures in Plastics," Jolie McLane, Michelle Khine, and Ralph Liedert (University of California, Oakland, Calif., and VTT Technical Research Centre of Finland Ltd., Espoo, Finland)

Superhydrophobicity has self-cleaning properties that help prevent the spread of disease for health applications. However, chemicals wear off and lose their hydrophobicity over time. Some structures that prevent bacterial adhesion are not superhydrophobic and do not have the benefits of superhydrophobic surfaces. McLane, Khine, and Liedert produced a superhydrophobic surface: by depositing a rigid material onto a shrinkable platform. The platform enables shrinking, thus trapping air pockets, which prevent water from wetting the surface. A master can be produced by molding an epoxy onto the shrunken surface with superhydrophobicity. This epoxy can, then, can be form molds for molding superhydrophobic containers.

Fire Resistant Plastics

U.S. Patent 10,427,337 (Oct. 1, 2019), "Method and Injection Molding System for Producing Intumescent Reaction Plastic Molded Parts and Reaction Plastic Molded Part," Herbert Muenzenberger (Hilti Aktiengesellschaft, Schaan, Liechtenstein)

It is difficult to produce intumescent plastic molded parts containing intumescent fillers without triggering their reaction. Muenzenberger produced an intumescent plastic consisting of a reaction plastic containing intumescent additives and glass fibers. The glass fibers stabilize the reactive mixture during processing. The homogeneous mass is then injection molded and hardened in the injection mold without reaction. The material will react under the intense heat of a fire.

Energy Absorption

U.S. Patent 10,427,375 (Oct. 1, 2019), "Architected Materials for Enhanced Energy Absorption," Jacob M. Hundley, Tobias A. Schaedler, Sophia S. Yang, and Alan J. Jacobsen (HRL Laboratories, LLC, Malibu, Calif.)

Energy absorption materials have been widely used to protect people and goods from damaging impacts and forces. However, improved impact protection materials are needed. Hundley et al. developed a material based on a three-dimensional lattice architecture with internal struts. Some of the struts are internally terminated along the thickness direction of the lattice structure and providing internal degrees of freedom for energy absorption. A typical composite consists of a face sheet bonded to the internal structure. The lattice structure is formed from photopolymer waveguides produced when a liquid photo-monomer is exposed to collimated ultraviolet light passed through a mask. The struts can be converted into solid metallic, polymeric, ceramic, or composite structures.

Retroreflective Materials

U.S. Patent 10,427,367 (Oct. 1, 2019), "Retro-Reflective thread, Method of Manufacturing Same and a Textile," Michael Chebrebrhan and Landa Hoke (U.S. Army, Washington, D.C.)

Improved retro-reflectivity where light from a localized source is reflected is needed. Ghebrebrhan and Hoke developed a retro-reflective thread in which an internal section with optically transmissive fibers optically aligned along their longitudinal axes. Then textiles with retro-reflective threads forming patterns in woven, braided, knitted, and spun fabrics may have unique optical properties because of the continuously curved surfaces and varying light angles. Examples include polypropylene fibers with metal cores.

Super Strong Films

U.S. Patent 10,427,345 (Oct. 1, 2019), "Continuous

Fabrication System and Method for Highly Aligned Polymer Films," Gang Chen, Jianjian Wang, Jonathan Kien-Kwok Tong, Hadi Ghasemi, Xiaopeng Huang, James Loomis, and Yanfei Xu (Massachusetts Institute of Technology, Cambridge, Mass.)

Improved strength or thermal conductivity of materials require controlled alignment of internal structures. Chen et al. has developed a process for continuous fabrication of highly aligned polymer films. A polymer-solvent solution is subjected to a high shear, high temperature, Couette flow to extrude a thin film having polymer chain disentanglement. This extruded thin film is frozen and the solvent evaporated to form a dried film. The dried film such as ultra-high molecular weight polyethylene is mechanically drawn using a constant force drawing system to align polymer molecular chains through plastic deformation.

Quantum Dot Films

U.S. Patent 10,427,392 (Oct. 1, 2019), "Functional Composite Film and Quantum Dot Film," Eijiro Iwase (Fujifilm Corp., Tokyo)

Quantum dots which emit light by incident radiation are usually sensitive to moisture or oxygen, leading to photooxidation. Iwase developed a protective film consisting of an inorganic support coated with an ultraviolet-curable urethane polymer, phosphoric acid compounds, and a silane coupling agent covering a quantum dot film. The innovation includes a polyurethane film with a urethane with a side chain having a curable urethane polyester with (meth)acryloyl group and at least one phosphoric acid and a silane coupling agent containing one (meth) acryloyl group. This film is then attached to a quantum dot film.

ABOUT THE AUTHOR

By Roger Corneliussen

Dr. 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 plastics-related 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:PATENTS
Author:Corneliussen, Roger
Publication:Plastics Engineering
Date:Jan 1, 2020
Words:1877
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