By: Barry Dean, Naperville, Illinois, USA BIOPLASTIC patents U.S. Patent 10,611,903 (April 7, 2020), “Highly Filled Polymer Systems”, Oliver P. Peoples, Johan van Welsem, Allen R.Padwa, Mansoor Akhthar Basheer Ahmed, Yelena Kann and David Boudreau (CJ Cheiljedang Corporation, Korea) Ref: WO2015/149029 This patent teaches a polyvinylchloride composition where high filler levels are used to enhance properties and a polyester additive is used to render improved processing and performance properties in the highly filled PVC compounds. The filler is talc, calcium carbonate or a combination of the two where levels of 25 to 60 parts per hundred PVC resin are used. Key teaching is the use of a polyester at levels of 1 to 10 parts per hundred PVC resin and the preferred polyester is a polyhydroxyalkanoate (PHA) homopolymer, copolymer or mixture of two polyhydroxyalkanoate polymers. In PVC technology higher loadings of fillers have been shown to significantly improve properties but it is key that the processing of the higher loaded materials proceed smoothly both for cost and final formed properties in film, sheet, laminates and rigid materials for decking, fencing and window profiles. PHA polymers are taught to offer reduced die pressure, lower fusion time and lower torque (ie reduced viscosity) while also allowing for improved flexural modulus and thermal performance via effective wetting and dispersion of the high-level fillers. Other bio-based polyesters such as polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT) and polycaprolactone (PCL) are also taught as effective in managing high loading levels of filler in PVC. The effect of the PHA polyester was wide ranging as illustrated in the examples with filler levels of 27.2 – 61.2 parts per hundred PVC with good fusion time and peak torque across the range of filler loading at constant PHA polyester loading. The PVC formulation also is modified with traditional heat stabilizers, antioxidants, UV stabilizer, waxes/lubricants and colorants. The use of the biopolymer PHA in PVC offers the potential for PHA to achieve high usage in a mainstay commodity resin, PVC, and could be a pathway to high usage and economy of scale for PHA. This section highlights recent IP (patent) activity that is relevant to the field of bioplastics. The information offered is intended to acquaint the reader with a sampling of know-how being developed to enable growth of the bioplastics and bioadditives markets. U.S. Patent 10,519,275 (December 31, 2019), “Polyester Comprising 2-Methylglutaric Acid, Process For Production Of The Said Polyester and Products Obtained Therewith”, Tiziana Milizia and Roberto Vallero (Novamont S.p.A., Italy) Ref: WO2013/153147 This patent teaches the incorporation of 2-methylglutaric acid in either of its enantiomeric forms or as a racemic mixture, at levels of at least 20 mole % of the diacid components in aliphatic polyesters or aromatic-aliphatic polyesters that offer a good balance of physical properties as well as biodegradability while offering improved thermal performance and improved toughness and elongation. 2-Methylglutaric acid is a linear 5 carbon diacid main structure with a singular methyl group in the 2 position (total six carbon diacid, ie 2-methy-1,5 pentanedioc acid). The incorporation of 2-methylglutaric acid allows for tailoring of polyesters based aliphatic diacids (e.g. adipic acid, suberic acid, sebacic acid and the like) and aliphatic diols (e.g.1,3 propanediol, 1,4-butanediol and the like) and aromatic diacid (, aliphatic diacid and aliphatic diols. Use of 2-methylglutaric acid are taught to offer good fabrication performance for films, fibers, sheets, thermoforming and blow molding. The incorporation of alternate monomers allow for tailoring of properties to meet evolving customer requirements. Illustration of the teaching was presented where a control polymer terephthalic acid/adipic acid/sebacic acid//1,4- butanediol was compared to a polymer having terephthalic acid/2-methylglutaric acid/sebacic acid//1,4-butandiol (2-methyl gluctaric acid was substituted in mole % for adipic acid. The polyester containing the 2-methylglutaric acid showed an 8 % improvement in tensile strength, a fourfold increase in elongation to failure and a two fold increase in energy to break. 56 bioplastics MAGAZINE [03/20] Vol. 15
Patents U.S. Patent 10,508,176 (December 17. 2019), “Foamable Resin Composition For Foam Sheet, Foam Sheet Process, Process For Preparing Particulate Polylactic Acid and Process For Preparing Foam Sheet”, Jun-Beom Shin, Sung- Yong Kang, Min-Hee Lee, Hea-Won Kwon and Kyoung-Min Kang (LG Hausys LTD, Seoul, Korea) A process is taught for preparing a polylactic acid particulate that is suitable for foaming and overcomes common issues with foamed PLA rendering foamed cell structure, impact resistance and surface appearance. U.S. Patent Application 2020/095420 (March 26, 2020), “Biodegradable Profile Extruded Articles”, Adam Johnson, Eric McClanahan and Joe B. Grubbs III (Danimer Bioplastics Inc (Bainbridge, Georgia) This patent application teaches alternatives to traditional disposable food service items made from polyethylene, polypropylene and poly (ethylene terephthalate); a food service item made from at least 25 % of a biodegradable polymer. The resin containing at least 25 % of a biodegradable polymer can be extrusion molded into utensils as well as tubular items such as drinking straws as well as medical tubing. The teachings focus on profile extrusion of polyhydroxyalkanoate biodegradable resins into tubular structures with polyhydroxyalkanoate homo- or copolymers as the main biodegradable resin with optionality to substitute a portion of the PHA with other known biodegradable polymers such as polylactic acid, polybutylene succinate, polybutylene adipate terephthalate and polycaprolactone. The biodegradable resin(s) can be further modified to include fillers, nucleating agents and plasticizer. This teaching offers the potential for environmentally friendly food service items such as drinking straws amongst others. The process involves taking polylactic acid in the form of pellets or powder into an extruder where a melt is formed and then taken into a spray nozzle with heated air. The air temperature is 300 to 500 C, injected at 100 to 1000 psi with an injection speed of 10 to 50 m/s. The molten spray is subjected to 2000 to 50,000 volts to enable melt electrostatic spray deposition. The resultant PLA particle is taught to be 1 to 100 micrometers in size and exhibits molecular weight of 100,000 to 200,000. The melt electrostatic spray deposition process provides a particle that in a sol-gel coating scheme renders an improved PLA foam as demonstrated by the 0.5 mm foamed prepared. The PLA microparticles can also be dispersed in PVC and polyurethane for foaming. U.S. Patent 10,577,494 (March 3, 2020), “Compositions And Films Comprising Polylactic Acid Polymer, Polyvinylacetate Polymer And Plasticizer”, Ning Zhou, Robert S. Clough, Derek J. Dehn, Jeffrey P. Kalish, William W. Merrill, Kevin M. Lewandowski and Jayant Chakravarty (3M Innovative Properties Company, St. Paul, Minnesota) Ref: WO2016/105998 A composition is taught comprising >10 weight % semicrystalline polylactic acid (PLA) polymer, 10 – 40 weight % polyvinyl acetate polymer based on the total amount of PLA polymers present. The polyvinyl acetate polymer exhibits a glass transition temperature (Tg) of > 25 C. In addition, 15 – 30 weight % polyester plasticizer and optionally an amorphous PLA polymer. This composition is targeted for backing of a pressure sensitive adhesive which can be used in the making of a tape or sheet. The film has a first heating scan endotherm of > 10 J/g but less than 40 J/g along with a glass transition temperature of 20 – 30 C. The semi-crystalline polylactic acid taught can comprise at least 90 weight % of L-lactide units and < 10 weight % of the D-lactide unit The film composition can be directly coated with the pressure sensitive adhesive layer via traditional coating methods such as roller coating, flow coating, spray coating and the like. The compositions tested showed good heat aging, peel strength, tensile strength, tensile elongation and tensile modulus. bioplastics MAGAZINE [03/20] Vol. 15 57
