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Moldable PTFE Powders

U.S. Patent 9,096,701 (August 4, 2015), “Aqueous Tetrafluoroethylene Polymer Dispersion, Process for Producing the Same, Tetrafluoroethylene Polymer Powder, and Molded Tetrafluoroethylene Polymer,” Nobuhiko Tsuda, Yoshinori Nanba, Yasuhiko Sawada, and Tetsuo Shimizu (Daikin Industries, LTD., Osaka, Japan).

Polytetrafluoroethylene (PTFE) materials are very useful but difficult to process. Aqueous fluoropolymer dispersions are available, but no PTFE dispersions have been produced. 

Tsuda et al. developed a tetrafluoroethylene (TFE) polymer aqueous dispersion with less than 1000 ppm fluorovinyl emulsifier. The suspended monomer is then polymerized, and a moldable powder is obtained by coagulation. The resulting powders can be molded into tubing for hydraulics, fuels, and chemicals.

“Marble-Like” Composites

U.S. Patent 9,090,769 (July 28, 2015), “Molded Articles having a Swirl-Like or Marble-Like Appearance and Compositions for Producing Same,” Bruce M. Mulholland (Ticona LLC, Florence, Kentucky, USA).

Structural plastics are used in more and more applications. Color and appearance remains a challenge, especially with multicolored materials. Polyoxymethylene (POM or polyacetal) is a particularly good polymer for metal-like parts, but coloring it is difficult.

Mulholland developed POM materials with a pigmented marble pattern effect. He formed at least two different immiscible phases for a swirl-like or marble-like appearance. The first phase consists of pigmented POM polymers, and the second phase contains pigmented polymers with melting temperatures 5-30°F (3-17°C) different than the POM melting point. The second phase may contain a thermoplastic elastomer, a glycol-modified polyethylene terephthalate, or a polyamide. It’s added at 5 wt% and contains a high concentration of colorants.

Recycling Polystyrene

U.S. Patent 9,096,698 (August 4, 2015), “Styrenic Resin Incorporating Recycled Polystyrene,” Jack M. Frost, Jason R. Vititoe, Nicole B. Loontjens, and Gary C. Welsh (Americas Styrenics, LLC, The Woodlands, Texas, USA).

Because of its properties, availability, and cost, millions of tons of polystyrene are used each year in many products. Unfortunately, because of its low molecular weight and sensitivity to contamination, recycling polystyrene is difficult and costly.

Frost et al. developed a polystyrene resin incorporating post-consumer recycled polystyrene by dissolving the collected and cleaned polystyrene in monomer and polymerizing the monomer while removing contaminants. The resulting polystyrene contains 5 to 50 wt% recycled polystyrene with enhanced properties. 

Functionalized Blends

U.S. Patent 9,090,765 (July 28, 2015), “Highly Functionalized Resin Blends,” Joel D. Schall, Eric Hernandez Edo, John G. Woods, David P. Dworak, Philip T. Klemarczyk, and Alfred A. DeCato (Henkel IP & Holding GmbH, Duesseldorf, Germany).

Crosslinking high-performance thermoplastics is used to improve compression set properties. Often crosslinking degrades other desired properties. There’s a need for resin compositions with high molecular weights and high crosslinked density. Such resin compositions would be particularly useful for seals and gaskets.

Schall et al. developed multi-functional polymeric resin blends with high crosslink density and high molecular weight. They developed poly(meth)acrylates having three or more functional groups. These highly functionalized resin blends are prepared using single-electron transfer living radical polymerization processes to produce a variety of blended resin systems which have tailored and enhanced properties. These resins are particularly useful in cure-in-place and mold-in-place gaskets, sealants, and adhesives.

Molding Chairs

U.S. Patent 9,090,034 (July 28, 2015), “Manufacturing Process for Forming a Chair Back,” Tim Fookes, Keith Shoemaker, Pete Beyer, and Mark Sherman (Haworth, Inc., Holland, Michigan, USA).

Often office chairs consist of molded seats and back panels supported together by chair frames. Features are added such as padded seats, mesh suspension fabrics, and lumbar support pads for additional lumbar support and comfort.

Fookes et al. developed an improved molded chair back using multiple mold shots to develop different performance characteristics in selected areas of the chair back. Multiple mold shots and selected materials such as glass-filled polypropylene enable different support areas in a single molded piece. The result is a more flexible and pliant surface providing more comfortable contact with the occupant’s back.

Tailored Molding

U.S. Patent 9,089,999 (July 28, 2015), “Method and Apparatus for Manufacturing Components Used for the Manufacture of Articles,” Anthony Carl Dean (Nike, Inc., Beaverton, Oregon, USA).

Wearable products such as shoes are difficult to mass-produce because of their extreme number of variations. However, Dean manufactured customized products using small individual molds based on scans of customers’ body parts, such as feet or wrists.

The body part is scanned, leading to a virtual design of a mold insert. An aluminum-filled nylon mold insert is formed using laser sintering, fused deposition modeling, and stereolithography. The mold insert is used to produce the wearable article, such as shoe soles, watch bands, or apparel. The molding materials can be rubber, vinyl, ethyl vinyl acetate, or other polymers.

Antibacterial Nanofibers

U.S. Patent 9,090,995 (July 28, 2015), “Process of Making an Antibacterial Nanofiber,” Yasuo Imashiro, Naokazu Sasaki, Yukiko Ogushi, and Mami Iizuka (Nisshinbo Holdings, Inc., Tokyo, Japan).

Antibacterial textiles are highly desired in medical and household applications. Usually the antibacterial property is achieved by coating the fibers; however, the coatings wear off, and they tend to be toxic.

 Imashiro et al. developed an antibacterial nanofiber with an intrinsic antibacterial property without a biocidal additive. It’s based on polymers with special functional groups. Fiber diameters are between 1 and 1000 nm, and the functional groups range from aldehydes to imides. The fibers can include polyester resins and polythiophenes. The active functional groups are attached to monomers used in forming the nanofibers.

In Situ Nucleating Agents

U.S. Patent 9,062,184 (June 23, 2015), “Method of Preparation of Nucleated Semi-Crystalline Polymer,” Miroslav Skoumal, Ladislav Pospil, and Petra Zboilova (Polymer Institute Brno, spol. s r.o., Brno, Czech Republic).

Polyolefins such as polypropylene are semi-crystalline polymers and often have relatively low toughness. Nucleating agents are capable of increasing the number of nucleating centers in the crystalline polymer and improving toughness. However, nucleating agents tend to agglomerate during processing, reducing their effectiveness.

Skoumal, Pospil, and Zboilova prepared an in situ nucleated semi-crystalline polyolefin via coordination polymerization. Nucleating agent is added to the suspension or the solution in a non-polar hydrocarbon solvent, or in concentrated organoaluminum, as part of the catalyst system for alpha-olefin polymerization. After polymerization, the agent remains dispersed, resulting in a higher elastic modulus in tension and flexure and increased toughness, compared to a non-nucleated sample.

Note: The above patents were selected from 100 to 400 plastics-related patents found each week from a review of 3,000 to 7,000 U.S. patents published each Tuesday. A complete list of plastics-related patents is listed by week and topic at www.plasticspatents.com. Readers are invited to visit this site to see the latest patents, without charge.