By: Barry Dean,
By: Barry Dean, Naperville, Illinois, USA Bioplastic Patents new series U.S. Patent 9,914,832 (March 13, 2018), ”Articles Produced By Thermoforming”, Maximillian Lehenmeier, Gabriel Skupin, Martin Bussmann, (BASF SE, Ludwigshafen DE) Ref: EP 2015/059301 The patent illustrates and teaches thermoforming compositions that improved impact strength based on blending compositions comprising a biodegradable polyester from succinic acid and 1,3 propanediol or 1,4 butanediol, an aliphatic-aromatic polyester from C6 – C18 dicarboxylic acid and terephthalic acid based on 1,3 propanediol or 1,4 butanediol, polylactic acid and at least one mineral filler, e.g. talc. The ratio of the degradable polyester from succinic acid and the diol to the polylactic acid component is from 2.5 – 3.1. The improved impact strength is taught to be a function of the level of the aliphatic-aromatic polyester used at levels of 5 to 14 percent. Thermoforming is a process where a sheet is heated a temperature to enable pliable forming of a shape (e.g., tray, cup, lids, containers etc). Polymer composition consistency and viscosity stability are key for shape integrity, reproducibility and scrap recycle. The performance feature taught in the above patent, improved impact is also dependent of polymer composition consistency and viscosity stability. The thermoforming compositions have polymeric content that is compostable and offers options for recycling. This section highlights recently granted patents that are relevant to the specific theme/focus of the Bioplastics Magazine issue. The information offered is intended to acquaint the reader with a sampling of know-how being developed to enable growth of the bioplastics markets. U.S. Patent 9,687,585 (June 27, 2017), “Thermoformed Poly-4-Hydroxybutyrate Medical Implants”, Matthew Bernasconi, Dennis Connelly, Said Rizk, David Martin, Simon Williams (Tepha, Inc Lexington, MA, USA) This patent teaches methods for producing thermoformed articles or precursors from poly-4-hydroxy alkanoate (P4HB) for medical applications. For example a film or sheet based on P4HB is thermoformed into a laminate from film and a mesh. The laminate can be used for a variety of devices directly implanted in the body for soft and hard tissue repair (wound management, reconstructive surgery, orthopaedic surgery). The inherent improved toughness of P4HB (Tg = - 45 to – 65 C) relative to other polyhydroxyalkanoates is taught as key for preventing breakage during the implantation and for part integrity during the healing process in vivo. The thermoformed parts can be further machined to produce the desired implant shape. Physical properties of the thermoformed mesh and mesh laminate show no detrimental effects from sterilization cycles. Viscosity consistency and control is key as with other materials in thermoforming processes; this technology calls out the need for intrinsic viscosity of < 3.5 dL/g but > 0.35 dL/g 44 bioplastics MAGAZINE [02/19] Vol. 14
U.S. Patent 10,214,316 (Feb 26. 2019), “Method For Manufacturing Biodegradable Packing Material, and Packages and Containers Made Thereof”, Kimmo Nevalainen, Ville Ribu, Jurkka Kuusipalo, Sami Kotkamo (Stora Enso OYJ Helsinki FI) Ref: PCT/FI2013/050997 The patent teaches multilayer biodegradable coating on a fibrous material, e.g. packing paper or packing board to enable heat sealing while providing biodegradable characteristics to the package coating. Typically polyethylene is used, but polyethylene is not biodegradable. This technology teaches using a multilayer co-extrusion where the innermost layer is a blend of polylactic acid and another biodegradable polymer (e.g. polybutylene succinate), a middle layer of polylactic acid and outer layer of polylactic acid and another biodegradable polymer, again a polybutylene succinate. This technology teaches that the melt index(viscosity) of the PLA and the ratio of the PLA: PBS significantly impact adhesion, heat seal temperature and co- extrusion line speed all of which are key to economic viability. The incorporation of biodegradable multilayer renders the package compostable and offers options for packaging recyclability. COMPEO Leading compounding technology for heat- and shear-sensitive plastics U.S. Patent 10,093,579 (Oct 9, 2018), “Process For The Production of Cementitious Material”, Hendrik Marius Junkers, Renee Maria Mors; (Green-Basilisk BV, Delft NL) Ref: PCT/NL2015/050526 The patent teaches a process for the production of cementitious materials comprising mixing cement starting material, a healing agent inclusive of a bacterial agent and a fibrous reinforcing material based on a biodegradable polymer with specific molecular weight and fiber length/diameter ratio. The technology illustrates using biodegradable polymers (polylactic acid, polyhydroxyalkanoate or polybutylene succinate) in fiber form serving two purposes; 1) assist in generating a strong material during the hardening process and 2) serving as the source for bacterial conversion to bio minerals which aid in crack repair/crack healing. The patent illustrates the bacterial agent can be aerobic or anaerobic in character. U.S. Patent 10,195,821 (Feb 5, 2019), “Bamboo Laminated Construction Panel and Method of Manufacture”, William D McDonald (Bamcore LLC Windsor, CA, USA) This patent teaches a bamboo laminated construction panel where at least two layers of prepared bamboo are laminated together with wood veneer outer layers. Bamboo as the core offers higher vertical load bearing strength, higher compressive strength and higher stiffness than other wood based building materials. In addition, bamboo offers faster growth cycles to timber grade material as well as better rot and insect infestation resistance to wood. The bamboo laminate construction can reduce the number studs required in other wood frame construction. Uniquely efficient. Incredibly versatile. Amazingly flexible. With its new COMPEO Kneader series, BUSS continues to offer continuous compounding solutions that set the standard for heat- and shear-sensitive applications, in all industries, including for biopolymers. • Moderate, uniform shear rates • Extremely low temperature profile • Efficient injection of liquid components • Precise temperature control • High filler loadings www.busscorp.com bioplastics MAGAZINE [02/19] Vol. 14 45
