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Controlling Bad Odors

U.S. Patent 8,927,078 (January 6, 2015), “Encapsulated Activated Carbon and the Preparation thereof,” Chieh-Chun Chau and William F. Patchen (Reynolds Consumer Products Inc., Lake Forest, Illinois, USA).

Garbage stinks, and stink reduction is good. Activated carbon is an effective adsorbent for odor reduction because of functionality and porosity. Small carbon particles are difficult to use, but they are useful fillers for plastics. However, when activated carbon is blended with a molten polymer, the molten polymer plugs up the pores and prevents sorption.

Chau and Patchen developed a masterbatch of encapsulated activated carbon particles for plastics and odor reduction. The activated carbon particles are encapsulated with a non-water-soluble, brittle amorphous polymer such as polystyrene. The encapsulating mixture also contains pore-forming additives such as calcium carbonate, magnesium hydroxide, and talc. The mixture with the carbon is extruded and pelletized for mixing with other plastics.

The activated carbon is only partially encapsulated with polymer, leaving voids. In addition, cracks in the encapsulant form pathways to the carbon pores. Thus the carbon retains its sorptive properties in the plastics. These pellets can be mixed with film resins and blown to form odor-reducing bags.

Tough Coatings

U.S. Patent 8,927,098 (January 6, 2015), “Hard Coating Film,” Soon-Hwa Jung, Heon Kim, Yeong-Rae Chang, and Hye-Min Kim (LG Chem, Ltd., Seoul, South Korea).

Shrinking electronics requires thinner and thinner materials on all levels, including coatings. Display windows are usually formed from glass or tempered glass; however, glass is heavy and brittle. Plastics could replace glass, but they require hard, abrasion-resistant coatings.

Jung, Chang, and Kim developed an abrasion-resistant coating for plastics based on crosslinked polyrotaxanes with other additives. Polyrotaxanes consist of a linear polymer threaded through a series of unattached cyclic molecules. The polymer moves freely through the cyclic groups but cannot be disconnected because of the chain’s end groups. This sliding motion provides impact protection because of the moving friction.

The chain ends are capped with acrylic groups, preventing the linear chain from escaping the molecular rings. The coating also contains a coupling agent for network formation and hardness. This coating is deposited and cured with radiation. The polyrotaxane and the binder resins are crosslinked, forming a strong, tough network structure.

Reactor PE Blends

U.S. Patent 8,933,175 (January 13, 2015), “Hyperbranched Polymers and Methods of Making and Using same,” Youlu Yu, Chung C. Tso, David C. Rohlfing, Paul J. Deslauriers, Melvin Hildebrand, Max P.McDaniel, and Qing Yang (Chevron Phillips Chemical Company LP, The Woodlands, Texas, USA).

Polyethylene materials are widely used because they are processable and cost effective. There is a constant push for special properties requiring new types of PE for new applications. Reactor production can make new polyethylenes with very little change in cost for these applications.

Yu et al. developed a PE blend of linear chains and “star branched” chains. The branched PE increases melt flow without reducing other desirable properties, making the material more processable. This is done by a two-stage Ziegler catalyst polymerization in which each stage provides resins with different branching. One stage produces unbranched, linear polyethylene, and the other stage produces star branched PE with several long chain branches from a relatively short core. The star branched resin reduces entanglement density, improving viscous flow.

Conditioned UHMWPE

U.S. Patent 8,933,145 (January 13, 2015), “High Temperature Melting,” Ebru Oral and Orhun K. Muratoglu (The General Hospital Corp., Boston, Massachusetts, USA).

Ultrahigh molecular-weight polyethylene (UHMWPE) materials are useful implant materials, but total joint implants need improved oxidative stability and wear resistance. Wear resistance can be improved by crosslinking. However, crosslinking reduces toughness and ductility.

Oral and Muratoglu produced crosslinked, wear- and oxidation-resistant, tough, and ductile UHMWPE materials by localized, high-temperature melting. They irradiated a starting material containing antioxidants with ionizing radiation and then heated the irradiated material to 200°C. After cooling, the material showed enhanced wear resistance and oxidation resistance without noticeable degradation in the other desirable properties. This process is carried out in 1 to 22% oxygen with a radiation dose of 25 to 1000 kGy.

Electrostatic Adhesion

U.S. Patent 8,932,703 (January 13, 2015), “Electrostatic Adsorbable Sheet,” Hiroshi Koike and Yuichi Yahagi (Yupo Corp., Tokyo, Japan).

Adhesives are usually used to attach posters to most surfaces, but removing posters in a still-useable state is nearly impossible, making them difficult to recycle or save.

Koike and Yahagi developed an electrostatic adsorbable sheet which can attach and display printed material on a surface due to electrostastic induction, with adequate durability. This sheet can be peeled off a support with minimal damage to the sheet. The sheet is a laminate where one layer is electrically charged by corona discharge or a high-voltage charging. After charging, the surface charge is removed by another discharge without affecting internal charges responsible for the adhesion.

Thus a poster can be sent to the site covered with a protective layer. On site, the protective layer is peeled away and the charged laminate is pressed onto the support surface.

Renewable Thermosets

U.S. Patent 8,927,685 (January 6, 2015), “Thermoset and Thermoplastic Compositions Derived from the Essential Oils of Herbs,” Matthew C. Davis (U.S. Navy, Washington, District of Columbia, USA).

The U.S. Defense Department is heavily dependent on petroleum for sources of mission-critical plastic composite materials. There is a need to find materials from renewable resources rather than the usual nonrenewable petroleum resources.

Davis has found that essential-oil products from plants represent a renewable resource for thermoset resins and plastics. There are many plants, especially herbs, which provide extractable essential oils. In particular, tarragon (Artemisia dracunculus) and star anise (Illicium verum) yield essential oils that are almost exclusively the isomers of 4-methoxyphenylpropene (estragole and anethole).

These products are transformed by metathesis to form phenolic dimers. These can then be inserted into polymerization reactions for polyesters, polycarbonates, polycyanurates, polyurethanes, polyetherimides, polyetheretherketones, and polysulfones. Applications in aerospace require high strength-to-weight ratios; these materials are lightweight and thermally resistant.

Moisture Curing 

U.S. Patent 8,937,141 (January 20, 2015), “Moisture Curable Organopolysiloxane Composition,” Sumi Dinkar, Edward J. Nesakumar, Anantharaman Dhanabalan, Shahid Murtuza, and Shayne J. Landon (Momentive Performance Materials Inc., Waterford, New York, USA).

Polymers having reactive terminal silyl groups can be hydrolyzed and condensed in the presence of water and organometal catalysts, enabling moisture curing. Organotin compounds such dibutyltin dilaurate are widely used as catalysts. Dibutyltin-containing formulations will be completely phased out in consumer applications during the next 4-6 years because of health concerns. Metals such as Ca, Ce, Bi, Fe, Mo, Mn, Pb, Ti, V, Zn, and Y can replace tin, though some of these, such as Pb, do not seem that safe of a choice.

Dinkar et al. developed Mn(III) complexes that can replace organotin for sealant and room-temperature vulcanizing formulations with silyl groups. The Mn(III) complexes are comparable or superior to organotin and enable tuning cure characteristics with good adhesion and storage stability. The reactive silyl groups can be introduced with silanes containing functional groups that can react with unsaturated hydrocarbons. In principle, silyl groups make any polymer crosslinkable with moisture.