By Jan H. Schut
When the South Texas section of the Society of Plastics Engineers, together with SPE’s FlexPack conference, host Polyolefins 2011 next Feb. 27-March 2 in Houston, new technologies will be on display from all over the world. Polyolefin developments include high isotacticity PP from China, the first process for thermoplastic nano fibers from the Czech Republic, and the first in situ dispersion of nanoparticles from the U.S.
FlexPack news focuses on doing more with less, including the first data on plastic made from waste CO2, new data on the first commercial nano layer blown film die, and some pioneering approaches to green energy in plastics plants. The conference program is still being finalized (www.spe-stx.org/conference.php), but here’s a preview of some of the new technologies to watch out for.
Jinliang Qiao, vice president at Sinopec Beijing Research Institute of Chemical Industry (www.sinopec.com), and director of the Polyolefin National Engineering Research Center in Beijing, China, will present “Aspects of the Polyolefin Industry in Mainland China.” Qiao was supposed to give a paper at Polyolefins 2010 on Sinopec’s recent developments to make PP with higher isotacticity for BOPP and pipe, but couldn’t attend the conference because of visa problems. Qiao is also named on a recent U.S. patent application for a “Process for the Preparation of High Performance Polypropylene” (U.S. Pat. Applic. # 20090326171), described as using “highly stereo specific Ziegler-Natta catalyst” to make PP with broad MWD and a high molecular weight fraction with low isotacticity using “asymmetrical external donor” technology instead of comonomer. Sinopec Zhenhai Petrochemicals commercialized this high performance PP in 2005.
Zhanhu Guo, assistant professor of chemical engineering, and a team from Lamar University (www.lamar.edu) in Beaumont, Texas, with Luyi Sun, assistant professor of chemistry, and a team from Texas State University-San Marcos (www.txstate.edu) will present “Magnetic Polypropylene Nanocomposites: Rheological, Electrical, Magnetic and Thermal Properties” for the first time. The two teams collaborated for over a year on a molecular approach to growing nanoparticles inside a polymer matrix like PP instead of melt compounding. Their initial work uses iron and iron oxide nanoparticles, but the technology reportedly applies to other nanoparticles as well. They use heat treatment to decompose metal precursors into metal nanoparticles, which are then encased in polymer, so that they cannot agglomerate. Guo and Sun say that this is the first time nano materials have been dispersed in situ. Dispersing nanoparticles by melt compounding is very difficult and nanoparticles tend to recombine when the material is melted again. Growing nanoparticles inside the polymer matrix disperses them more evenly, and they stay dispersed. The researchers also discovered changes in physical properties like 115 degrees C higher HDT along with magnetic properties. The teams are looking for industrial partners to develop commercial applications for the technology.
Stanislav Petrik, director of business development at Elmarco s.r.o. in the Czech Republic (www.elmarco.cz), will introduce “Olefinic Nanofibers for Filtration and Other Applications.” Elmarco, which has a U.S. office in Morrisville, N.C., has presented its unusual “Nanospider” equipment previously at fiber, filtration, and new material research conferences in the U.S., but not to the plastics industry. Potential applications for nano fibers include filtration and reinforcements for compounding, extrusion and molding of composites. Reportedly the only commercial nano fiber process, Nanospider can make plastic nano fibers 0.030 to 0.500 micrometers in diameter depending on material vs 0.9 micrometers for melt blown or spun micro fibers or 80 micrometers for a human hair.
The patented (U.S. Pat. # 7585437) process uses a drum like high voltage electrode (30-120 kV), partially submerged in liquid to blow nano fibers out of a thin film of liquid, rather than off a wire or capillary, so there are no nozzles, needles or spinnerets to clog or need cleaning. The technology was initially developed and commercialized to spin polymeric fibers from solution in acid, solvent or water. Elmarco has offered production lines with 5-foot-long electro-spinning electrodes since 2005 for nylon 6, PVA (polyvinylalchohol) and polyurethane and biopolymers like gelatin and cellulose. Elmarco’s latest development is a lab line for melt-blown thermopolastic nano fibers like PP. Elmarco has also designed but not yet commercialized commercial equipment for thermoplastic nano fibers. Competing methods under development to make nano fibers include “fine hole” melt blown and “islets in the sea” melt blown under water, but both reportedly make nano fibers with greater diameter variation than Elmarco’s method and aren’t yet available on a commercial scale.
Sanjeev Naik, manager of polymer technology development at Novomer Inc. in Waltham, Mass. (www.novomer.com) will present “Properties of Films Made With Sustainable CO2-Based Polymers and Blends Thereof” for the first time. Novomer is a start-up company, since 2004, commercializing aliphatic polycarbonates and other chemicals and polymers made from waste carbon monoxide and carbon dioxide. Novomer’s catalyst technology, invented at Cornell University, can copolymerize CO2 with an epoxide like propylene oxide or ethylene oxide to make poly(propylene carbonate), or PPC, and poly(ethylene carbonate), or PEC, respectively. PPC and PEC target applications like bottles, films, and coatings for beverage cans, using conventional plastics processing equipment.
Novomer recently scaled up production of PPC using facilities at Eastman Kodak Co. (www.kodak.com) in Rochester and at Albemarle Corp. in Baton Rouge, La. (www.albemarle.com) with $18.4 million in federal stimulus funds from the U.S. Department of Energy. Pilot plant production at Albemarle has reached hundreds of kilos and will soon reach thousands of kilos, polymerizing resins with up to 50 wt% CO2 recovered from ethanol fermentation and natural gas wells as feedstock. PPC thus made was extruded into films on an 18-mm single screw extruder with a 6 in. die and also blended with polyolefins on a 30-mm twin-screw lab extruder. The first preliminary data on mechanical properties of PPC and PPC blends and oxygen and water vapor permeability of PPC and PPC blend films will be presented at Polyolefins.
Bruce Foster, technical sales manager at Mica Corp., Shelton, Conn. (www.mica-corp.com), will talk about “New Heat-Seal Constructions,” based on Mica’s development of water-based heat-seal emulsions for coating plastic film, paper or foil substrates. Emulsion coating instead of extrusion coating can save material several ways. It allows patterning, so a sealant layer for lidding can be applied only where needed instead of all over a web. It can also be used in a hybrid with a less expensive commodity PE layer, i.e. 35 microns of commodity PE plus 5 microns of heat-seal coating vs 40 microns of a more expensive extruded sealant layer. Mica introduced its coating technology at Polyolefins 2010 with two grades. It now offers five grades, plus experimental versions, and has its first commercial application. Coatings are shipped in drums of 40% solids diluted in water ready to use.
Henry Schirmer, founder of BBS Corp., Spartanburg, S.C. (firstname.lastname@example.org) will present “Nano-Layer Effects in Blown Barrier Films Part 2,” his second paper on BBS’s Layer Sequence Repeater, which can take one, two or three materials and create a nano layer stack, then insert the stack between micro layers in BBS’s Modular Disk Die for blown film. BBS’s big news, however, won’t be in the paper. It’s that the Disk Die and Layer Repeater are now offered commercially for the first time by Jin Ming North America in Tryon, N.C., a unit of Guongdong Jin Ming Plastics Equipment Co. in China (www.stjm.com, www.jinmingna.com), which showed a Modular Disk Die for 29 layers at the Kunststoff 2010 Show in Dusseldorf in November. Jin Ming and BBS have prototyped a new design of the disk die that will allow bubble cooling for the first time and improve output.
BBS’s paper shows how film with four conventional layers surrounding a nano-layer stack of 25 alternating layers of EVOH and nylon 6 (LDPE +tie + [N6/EVOH…25 nanolayers ..EVOH/N6] + tie + LDPE) has a different crystalline structure with lower melt temperature than annealed EVOH. This was attributed to more rapid air-quenching with nano layers than with micro layers. These nano-layer barrier filsm could be stretch-oriented and by implication thermoformed at temperatures between 60 and 100 C, well below the melting points of both nylon and EVOH, BBS says. Nano-layer EVOH/nylon 6 film also showed greater toughness and flexibility with equivalent barrier performance vs micro layer film with single layers of the same amounts of EVOH and nylon. Test data was generated by coauthors from Curwood Inc. in Oshkosh, Wis. (www.curwood.com) and Soarus LL in Arlington Heights, Ill., a unit of Nippon Gohsei in Japan, which sells EVOH in North America (www.soarus.com).
Olle Mannertorp, president of Multifilm Packaging Corp., Elgin, Ill., (www.multifilm.com), will present “Geothermal Systems – A Case Study,” describing Multifilm’s installation of a geothermal heat exchange system to supply process cooling water as well as heating and air conditioning to their plant. The system has reportedly saved the company 25% off its annual energy cost, or about $120,000/year. Multifilm oversaw the installation itself, using a consultant to study the necessary water volumes and temperatures needed for efficient heat exchange. Another consultant designed the flow system, and a plumbing company built it. The return on investment was initially going to be 6.5 years, which the company felt was too expensive. A federal grant of $200,000 was available, which brought the ROI down to 4.5 years. Another factor in the decision was big savings in service, maintenance and propylene glycol for their previous dry coolers, Mannertorp says. Multifilm is aware of industrial food processing plants in Scandinavia that use geothermal cooling, but isn’t aware of any other plastics processor using it.
John Waffenschmidt, vice president environmental science at Covanta Energy Corp. in Fairfield, N.J., (www.covantaholding.com, http://www.covantaenergy.com), will deliver papers in both the Polyolefin and FlexPack sessions. In the Polyolefin session, Covanta will present an over view of the operational and environmental benefits of energy-from-waste technology to generate electricity from burning municipal waste. There are 87 WTE plants in the U.S. in 25 states, which recover about 550 kW hours of electricity per ton of municipal waste, plus about 50 lb of metals, and leave an inert ash residue that is roughly 10% of the original waste volume. Landfill Gas To Energy generation is also a green option, burning methane for electricity, though this option reportedly yields less energy and has a greater climate change effect. In the FlexPack session, Covanta will discuss how solid waste issues impact plastics processors and present novel ways to source energy from non-fossil fuel. One example is an energy-from-waste facility in Niagara Falls that is co-sited with manufacturing plants, reducing their overall carbon use.