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Issue 06/2020

  • Text
  • Renewable
  • Biodegradable
  • Films
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  • Biobased
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  • Plastics
  • Bioplastics
Highlights: Films / Flexibles Bioplastics from waste-streams Basics: Eutrophication

By: Barry Dean,

By: Barry Dean, Naperville, Illinois, USA BIOPLASTIC patents U. S. Patent 10,767,026(September 8, 2020), “Process For Degrading Plastic Products”, Marie-Laure Desrousseaux, Helene Texier, Sophie Duquesne, Alain Marty, Mediha Aloui Dalibey and Michel Chateau; Carbios(Saint-Beauzire, France) Reference: WO2017/198786 This patent is included as it teachings reflect the intersection of bio based and fossil fuel based polymers with regard to recycling of post consumer waste. This patent teaches a process for depolymerisation of plastic products, e.g. polyesters such as polyethylene terephthalate and/or polylactic acid. The process taught uses two steps; first an amorphizing process to decrease the crystallinity of the polyester and second, depolymerising the polyester to low molecular weight oligomer and base monomer(s). The amorphizing step requires subjecting the polyester to temperatures above crystallization temperature and melting temperature followed by temperature below the glass transition temperature; ie clear the residual crystallinity and quench below the Tg; this can be accomplished using an extruder with cold water bath quench. The depolymerisation step involves a biological depolymerisation employing a depolymerase and/or a microorganism expressing or excreting a depolymerase. Of particular note, prior to the depolymerase catalyzed hydrolysis, the polyester should be ground to < 500 um particle size to maximize surface area. This process also teaches applicability to PBAT and PHA homo- and copolymers as well as other polyesters. The amorphizing step is taught to be key in obtaining depolymerisation levels of 87 – 94 % 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 bio-additives markets U.S. Patent 10,774,197(September 15, 2020), “Photodegradation Resistant Biodegradable Films”, Catia Bastioli, Luigi Capuzzi, Claudio Russo and Tommaso Martinelli; Novamont S.p.A (Novara, Italy) and Consiglio Nazionale delle Richerche (Rome Italy) Reference: WO2014/057001 This patent teaches biodegradable films which offer high resistance to photodegradative processes, such as sunlight and where the UV stabilizer is based on polyphenols that are bio-derived. The biodegradable film are aliphatic or aromaticaliphatic polyesters particularly suitable for mulch films where microorganisms promote degradation of the film over time such that at the end of the cultivation cycle the film is sufficiently degraded and does not need to be removed from the field. As these films require UV stability, synthetic UV stabilizers are effective but remain at the end of the films utility and can accumulate in the ground. Taught is a category of polyphenols of plant based origin that slow the photodegradative processes; specifically polyphenols derived from milk thistle seeds. Specifically the use of 0.1 – 10 % by weight of a polyphenol silibin, silidanin, isosilibin or silicristin demonstrates stabilization of the polyester mulch film to the photodegradative processes. Films prepared and subjected to UV lamp exposure support the benefits of the bioderived polyphenol as stabilizer against photodegradation based on higher retention of tensile strength, elongation at yield, modulus and impact performance than the control films without the bio-derived polyphenol 48 bioplastics MAGAZINE [04/20] Vol. 15

Patents U.S. Patent 10,744,183(September 15, 2020), “Polyarylene Ether Sulfones”, Narmandakh Taylor, Charles R. Hoppin, Ahmed Kahn, Henry Bradley and Suresh R. Sriram; Solvay Specialty Polymers USA, LLC (Alpharetta, Georgia USA) U.S. Patent 10,793,781(October 6, 2020), “Method for Producing Biohydrocarbons”, Maija Hakola and Tomi Nyman; NESTE OYJ(Espoo, Finland) Reference: WO2016/184893 A method/process is taught for producing biohydrocarbons which includes providing an isomeric raw material derived from a bio-renewable feedstock. Chemical processes include deoxygenation, hydrodeoxygenation, hydrotreatment or hydrocracking to obtain a stream that is at least 65 % isoparaffin in character. This isoparaffin stream is thermally cracked limiting the temperature to no greater than 825 C. The feedstock taught can be tailored to include a mixture of hydrocarbons in the C10 – C20 range and/or the C5 – C10 range. A feedstock that is 49 % isoparaffin and 51 % n-paraffin renders a thermally cracked biohydrocarbon that is predominantly ethene(31.95 – 39.55 %) and propene(13.38 – 21.34 %) depending on the reaction outlet temperature. The ethane and propene can be used to make bioderived polyethylene and polypropylene as well as bio derived intermediates such ethylene glycol and propylene glycol. This patent teaches a partially renewable high performance polymer, a poly(arylether sulfone). Polyarylether sulfones are in the class of engineering resins which typically offer a good balance of mechanical properties and at least one of the following performance features; high use temperature performance, high practical toughness and/or exceptional chemical resistance. The poly(arylether sulfone)s being taught here are made via nucleophilic displacement reaction of a 4,4’dihalodiphenylsulfone and a bioderived 1,4:3,6-dianhydrohexitol in a apolar solvent such as sulfolane in the presence of potassium carbonate at elevated temperature. The 1,4:3,6-dianhydrohexitol are produced from starch via enzymatic degradation into d-glucose and d-mannose followed by sequential hydrogenation and dehydration rendering isosorbide and isomannide. These fused ring V-shaped diols make good candidates for monomers for imparting high temperature performance to polymers. The process taught provides very good high temperature performance materials when the weight per cent of total monomer in solvent is between 25 – 42 %. Glass transition temperatures of the formed poly(arylether sulfone)s range of ~ 215 – 235 C are achieved which render these materials useful in electronics, medical devices and other shaped articles having material renewable content from the isosorbide or isomannide. U.S. Patent Application 2020/0270652(August 27, 2020), “Producing Resins From Organic Waste Products”, Dane H. Anderson and Jeff H. Anderson; Full Cycle Bioplastics(Richmond, California USA) An integrated process and design is taught for producing a polyhydroxyalkanaoate copolymer from an organic waste product that consists of a first and second volatile fatty acid where the ratio of the first and second volatile fatty acid are adjusted prior to introducing the fatty acid mixture to a polyhydroxyalkanoate producing bacteria and subsequently extracting the polyhydroxyalkanoate copolymer from the bacteria. The volatile fatty acids can be produced using an acidogenic bacteria with an organic waste stream, for example(but not limited to) organic liquid lechate extracted from industrial composting processes. The process consists of liquefaction of biofeedstock materials, volatile fatty acid production, volatile fatty acid separation, bioplastic production and polyhydroxyalkanoate isolation. The process teaches on line volatile fatty acid mixture control to achieve the desired polyhydroxyalkanoate copolymer composition being tailored for end use in films, packaging and other molded/formed articles. U. S. Patent Application 2020/0332112(October 22, 2020), “Biodegradable Filaments and Use Of Such Filaments”, Laurens Jean-Marc L. Goormachtigh, Femke Faelens and Frans Van Giel; Beaulieu International Group NV (Waregem, Belgium) Reference: WO2019/122191 This patent application teaches a filament composition used to make groundcover where there is a first biodegradable polymer (40 – 90 % by weight) and a second biodegradable polymer (10 – 60 weight %) where the first biodegradable polymer exhibits a visual degradation rate faster than that of the second biodegradable polymer when is use as woven mat/ netting as groundcover for temporary control of erosion or protection of ground cover/new growth. The first biodegradable polymer can be selected from polycaprolactone, polybutylene succinate-coadipate, polyhydroxyalkanoate or mixtures; preferred are polycaprolactone or polyhydroxyalkanoate. The second biodegradable polymer can be selected from polylactic acid, polybutylene succinate, polybutylene adipate-co-terephthalate; preferred is polylactic acid. The visual degradation of the first polymer is 4 – 6 weeks to achieve 80 % degradation and for the second polymer 25 – 42 weeks to achieve 80 % degradation. The examples presented teach the balance and trade-offs of mechanical properties and rates of degradation based of the content and type of the first and second biodegradable polymers. bioplastics MAGAZINE [04/20] Vol. 15 49

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