By Jan H. Schut
The SPE’s first Eurotec conference, November 14-15 in Barcelona, Spain, is a European version of ANTEC, the SPE’s perennial conference highlighting new technology. Publications for the inaugural Eurotec didn’t have to be absolutely new the way ANTEC papers do. Still the conference assembled an impressive array of technologies presented either for the first time, or for the first time to a general plastics audience.
Two papers presented new multi-step combinations of different processing technologies, involving some kind of self-closing mold. Two papers described new compounds with properties enhanced by specially synthesized round polymer particles or molecules. Two papers described processes that replace all or part of the friction heat of plasticizing with convection heat for lower shear. Several papers described new starch based biopolymers, including a microwave-foamed starch and barley fiber composite plastic.
“Stages Molding: A Novel Technology to Produce Plastic Parts” by Miguel Rodriguez-Perez, director of the Cellular Materials Lab of the University of Valladolid in Spain (www.cellmat.es). The patent-pending technology uses self-closing molds, which require no outside clamp pressure, and allows very low pressure molding (typically below 15 bar). Molds are filled with pellets or molten plastic, then the mold itself is heated either with hot oil or electric resistance heaters. Pressure can be created by a chemical blowing agent in the material for foam-core parts or by a hydraulic manifold for solid parts. The process is being used commercially and can make large parts with reduced weight. ABN Pipe Systems Group in A Coruna, Spain, is a research partner in the development.
“New Processes for Large Scale Automotive Production of Composite Applications” by Marcus Schuck, director of R&D, Jacob Plastics GmbH, Wilhelmsdorf, Germany (www.jacobplastics.com). This new technology, developed over the past three years and now in prototype, combines injection and compression molding to create complex hollow parts in a single tool. FIT Hybrid (fluid injection technology), which won a Germany technology award in 2010 and a JEC innovation award in France earlier this year, makes a tube-like hollow thermoplastic composite. First two thermoplastic textile sheets are preheated with IR radiation; plastic is then injected between the sheets to make a sandwich preform. An injection mold closes over the preform, pinching and embossing the edges. Gas is then injected into the mold to shape a hollow part, driving most of the “filling” plastic out of the mold. The hollow part can then be over-molded with ribs and other solid features.
“Impress, an Innovative Pilot Injection-Compression Molding Platform for the Production of Micro-Nanostructures on Plastic Parts” by Mael Moguedet, head of plastronics business, PEP Centre Technique de la Plasturgie, Oyonnax, France (www.poleplasturgie.net). IMPRESS adds micro-nano (100-500 nm ) surface features to molded plastic using “self assembly” coatings, interference lithography, nano lasers, and plasma etching. Micro nano patterned nickel shims are being tested in molds at partner plants now.
NEW EXTRUSION AND FILM TECHNOLOGIES
“Natural Gas as Main Energy Source for Polymer Plasticizing with a Specially Designed Heat Exchanger” by Felix Heinzler, research assistant, Institute of Engineering and Plastics Machinery, University of Duisburg-Essen in Germany (www.uni-due.de). A lab-scale demonstration device melts plastic in a gas-fired barrel heater with a specially designed heat exchanger and a melt-pump to move the plastic. Plasticising polymers without friction saves energy cost and allows almost shear-free extrusion.
“New and Improved Screw Technology for Processing NatureWorks INGEO” by Timothy Womer, president of TWWomer & Associates LLC, Edinburg, Pa. (www.twwomer.com). A modified barrier screw design for PLA produces melted and semi-melted material pools, which are homogenized and fully melted using convection heat in a special distributive mixer. The PLA screw is being tested by NatureWorks LLC, Minntonka, Minn. (www.natureworksllc.com), and is available from machine builder R&B Plastics Machinery, Saline, Mich. (www.rbplasticsmachinery.com).
“Production of a Functional 3D Plastic Pane” by Ralf-Urs Giesen, researcher, University of Kassel in Germany (www.uni-kassel.de). A 7-layer polycarbonate panel is being developed for car sun roofs, which will be able to change from clear to blue to keep the car interior cool. First is a clear PC substrate, then a conducting indium-tin-oxide layer is sputtered on, then an electrochromic layer of PEDT/PSS (poly 3,4 ethylenedioxythiophene/polystyrene sulfonate), followed by a thick layer of an ion conducting polymer electrolyte, then an ion storage layer of TIO2, another conductive indium-tin-oxide layer, and finally another structural layer of PC. The university is now checking the thermoformability of the layers. Sunroofs could also be injection molded behind a functional film with the same layers.
“Strain Hardening: An Elegant and Fast Method to Predict the Slow Crack Growth Behavior of HDPE Pipe Materials” by Linda Havermans, lead scientist, SABIC Technology and Innovation, Geleen, the Netherlands (www.sabic-europe.com). A clever short-cut can test PE pipe resins for slow crack growth. The ASTM standard test, known as the Notched Pipe Test, or NPT, can take up to a year of testing and requires a lot of pipe. The full notch creep test (FNCT) requires only a few 100 grams of plastic, but takes just as long. SABIC found that testing strain hardening modulus, from a stress-strain curve at 80 degrees C, correlates perfectly with the results of both the NPT and FNCT, and can be done in a lab in only a few hours using little material. SABIC uses this method for material development and quality control and suggests the test as an easy, inexpensive way for pipe converters to test incoming resin lots for crack resistance.
NEW COMPOUNDING TECHNOLOGIES
“Modification of Amorphous Plastics by Compounding with Colloids” by Viola Sauer, scientific assistant, Institute for Materials Engineering – Polymer Technology, University of Kassel in Germany (www.uni-kassel.de). Colloids are spherical knot-like particles of cross-linked polymer chains, which can be penetrated by other polymer chains of the same monomer when mixed in a suitable solvent. Synthetically creating colloids and conventionally compounding them into a similar polymer—in this case PMMA colloids into PMMA–improves flex modulus and impact strength without hurting clarity. Colloidal composites were tested with up to 15% dry colloid content.
“High Flow Glass-Fiber-Filled Aromatic Polyamide Resins” by Frans Mercx, chief scientist, LNP technology team leader, SABIC Technology and Innovation, Bergen op Zoom, the Netherlands (www.sabic-ip.com). SABIC has investigated highly branched dendritic aliphatic polyester molecules as flow enhancers, using dendritic molecules with 32 terminal OH groups and mol. wt of 3600, more than twice the normal size. At 0.5 to 1% loading in highly glass-filled nylons (30%, 40% and even 50%) melt flow rate improves over 100% without hurting mechanical properties.
NEW BIOPOLYMER MATERIALS
“2,5-furandicarboxylic Acid (FDCA); A Versatile Building Block for a Very Interesting Class of Polyesters” by Matheus Dam, team leader at Avantium Chemicals BV, Amsterdam, the Netherlands (www.avantium.com). Shell spin-off Avantium is bringing a 40-ton-yr pilot plant on-stream in Holland to make FDCA (2,5-furandicarboxylic acid), a new monomer to make PEF (polyethylene furanate). PEF will be a new bio-based polyester that is like PET, but has six-times better barrier properties targeting all-biopolymer beverage bottles.
“Silicone Modified Bio-based Coatings from Soyabean Oil for Water Resistant Papers” by Shilpa Manjure, manager of product development, Northern Technologies International Corp., Circle Pines, Minn. (www.ntic.com). This developmental biopolymer coating is made of soybean oil bonded to vinyl trimethoxy silane in the presence of peroxide. The patent-applied-for technology (U.S. Pat. Applic. # 2010008387), licensed from Michigan State Univ. (www.msu.edu), targets waterproof coatings on paper for food packaging and was funded by the Department of Defense. If the silanol cured at ambient moisture, it is low in viscosity and would soak into paper. So the silanol is partially cured with heat and 4% water to make it thick enough for coating.
“FlourPlast: Creating New Opportunities for the Bioplastic Industry. Process Structure Property Relationships of a Novel Bioplastic Polymer” by Jeroen van Soest, innovation manager, Rodenburg Biopolymers and Optimum Bio Plastics, Oosterhout, the Netherlands (www.biopolymers.nl). Optimum offers a family of pelletized thermoplastic flours made by melt-compounding the starch, proteins, sugars, fats and fibers in the flour with vinyl acetate copolymer. Pelletized FlourPlast grades range from flexible to rigid for melt blending into biopolymers like PLA or PHA or polyolefins like PE or PP. They have been commercial for about a year and are available in the U.S.
“Development of Starch-Biobased and Biodegradable Plastics for Use in Trays for Food-Packaging” by Alberto Lopez-Gil, biopolymer researcher at the Cellular Materials Lab of the University of Valladolid in Spain (www.cellmat.es). A novel replacement for foamed PS trays is being developed out of starch-based polymer reinforced with barley straw fiber. It can be foamed using microwave heat, which is absorbed by moisture in the starch polymer composite, resulting in a light-weight bio-based plastic.