Beyond Micro: Nano Injection Molding Is Finally Commercial

By Jan H. Schut

After nearly 30 years of R&D, nano molding may be too small to see, but it’s real. Nano details that are so small they can’t even be seen under a microscope are being injection molded. They’re read by electron microscopes or by defraction using a laser pointer. Molded nano features include invisible logos on parts to prevent counterfeiting, functional surfaces like radar deflection, and hologram-like iridescence.

The original technology was developed in the 1980s by what is now the Karlsruhe Institute of Technology in Germany (www.kit.edu) to make nozzles for uranium enrichment for atomic energy. Called LIGA, short for lithography, electroplating and molding in German, it uses concentrated X-rays to cure successive layers of PMMA to make highly precise, straight-sided parts, which are then electroplated with nickel alloys or gold.

But X-ray LIGA has drawbacks for nano molding. Vertical walls are hard to demold, so it would only work for shallow nano surfaces. The technology also requires a costly, colossal X-ray concentrating machine called a synchrotron. KIT’s is the size of a very large warehouse. An even larger one in Switzerland is the size of a small stadium. Only two companies use X-ray LIGA commercially – Microworks GmbH in Eggenstein-Leopoldshafen, Germany (www.micro-works.de), a spinoff from KIT in 2007, and HT MicroAnalytical Inc., Albuquerque, NM (www.htmicro.com). Neither has made an injection mold insert.

Nano-featured injection mold inserts are beginning to be made by UV-cured LIGA, which is less expensive than X-ray, and by nano imprint lithography. Both lithography technologies have been used for over a decade to emboss nano features on film, but only recently tried for injection molding. Mimotec SA in Sion, Switzerland (www.mimotec.ch), was founded in 1998 to develop UV LIGA for micron-scale molding technology, as the name says. Instead Mimotec’s market turned out to be direct production of electroplated watch parts. Mimotec only made its first commercial nano mold insert with UV LIGA three years ago for a French office supply company. The insert, mounted on an ejector pin, puts an invisible logo on parts for authentication.

Mimotec’s patented UV-LIGA technology (EP 2855737) exposes up to three layers of polymer to make a nano feature. First a flat silicon substrate is coated with an epoxy-based photo-sensitive polymer called “SU8.” Then the reverse of the part is exposed to UV laser light using a mask. After UV exposure it takes a week for each layer to harden unless a curing agent is used. Once the layers harden, uncured polymer is washed away, and the cavity is sent out for electroplating with nickel, nickel phosphorous or gold. Electroplating is up to 0.8 mm thick, much thicker than conventional electroplating, which is only microns thick.

Mimotec’s sister company, Sigatec SA in the same location (www.sigatec.ch), engraves directly on an oxidized surface layer of silicon to make functional nano-features. Sigatec’s Deep Reactive Ion Etching was used to emboss film, for example for a medical part for DNA analysis with 42 million truncated cones on the surface, each 3 microns in diameter by 3.5 microns high.

The ant on the November 1992 cover of Scientific American holds a micro gear made by then revolutionary X-ray LIGA lithography and electroplating. Today faster, less expensive UV LIGA makes shims for injection molds for micro gears and nano-scale molded features. Photo: Mimotec.

The ant on the November 1992 cover of Scientific American holds a micro gear made by then revolutionary X-ray LIGA lithography and electroplating. Today faster, less expensive UV LIGA makes shims for injection molds for micro gears and nano-scale molded features. Photo: Mimotec.

Tecan Precision Ltd. in Weymouth, Dorset, U.K. (www.tecan.co.uk), founded in the 1970s, is also an early user of UV LIGA, making metal masks for vacuum deposition for electronics with micro features. Tecan has also taken customers’ nano-structured masters and replicated them to make injection mold shims 200-300 microns thick, electroplated with sulphamate nickel.

NEWER VARIATIONS ON LIGA

Two other companies offer equipment for mask-less UV LIGA for nano mold inserts, which is reportedly less expensive and faster than using a mask. LPKF Laser & Elektronics AG, Garbsen, Germany (www.lpkf.com), a maker of laser equipment for printed circuits, offers Laser Direct Imaging technology, which guides a UV laser with what LPKF calls a “2D acoustic/optic deflector.” LPKF’s ProtoLaser LDI exposes photo resists by positioning the laser spot with “better than 1 nanometer precision,” using a UV laser wave length of 375 nanometers at a maximum speed of 100,000 spots per second. It targets molding microfluidic parts like lab-on-a-chip medical devices for blood testing and can even create rounded nano structures.

UV LIGA technology exposes a photo resist layer using a mask to define a part or its reverse. LPKF Laser & Elektronics builds mask-less UV LIGA equipment that can create rounded micro and nano details like the channels on this template for a lab-on-a-chip medical device.

UV LIGA technology exposes a photo resist layer using a mask to define a part or its reverse. LPKF Laser & Elektronics builds mask-less UV LIGA equipment that can create rounded micro and nano details like the channels on this template for a lab-on-a-chip medical device.

Nanoscribe GmbH in Eggenstein-Leopoldshaven, Germany (www.nanoscribe.de), another spinoff from KIT founded in 2007, makes a commercial mask-less 3D printer for nano parts, called the “Photonic Professional GT.” Nanoscribe’s patented light absorption reaction (U.S. Pat. Applic. # 20120218535) uses electromagnetic radiation to trigger a local photo reaction in the coating with either positive or negative-tone photo resist. Nanoscribe also has a patented LIGA process (U.S. Pat. # 8986563) that uses AZ MiR 701 polymer from Merck Performance Materials GmbH, Darmstadt, Germany (www.emd-performance-materials.com), for positive photo resist and SU8 epoxy for negative resist. Parts can then be electroplated.

Temicon GmbH in Dortmund, Germany (www.temicon.com), founded in 2005, uses Laser Interference Lithography and UV LIGA to make shims for micro embossing down to 0.2-micron details like a “moth eye” anti-reflective film for laminated display screens. Temicon is developing customized injection mold inserts for lab-on-a-chip parts, which Temicon can injection mold in-house. Temicon merged in 2014 with Holotools GmbH in Freiburg im Breisgau, Germany (www.holotools.com), a spinoff in 2001 from the Fraunhofer Institute for Solar Energy Systems in Freiburg (www.ise.fraunhofer.de). Holotools specializes in large area nano-structures without seam lines for embossing down to 200 nanometers.

FIRST NANO IMPRINT LITHOGRAPHY FOR MOLDS

At least five companies also use processes loosely called “nano imprint lithography” or NIL, including two with technology for steel molds, not electroplated shims. (An electroplated nickel shim is typically good for only a few 100,000 injection shots, but the original LIGA part can be used multiple times to make new molds.) NIL Technology ApS (www.nilt.com), a spinoff from the Danish Technical University in Lyngby, Denmark in 2009, uses patent-applied-for technology (U.S. Pat. Applic. # 20120244246) to put nano patterns onto a non-planar existing mold. NIL Technology first etches a nano pattern down to 80 nanometers onto a silicon wafer, then uses the wafer to emboss the pattern on film. Nano-featured film is then applied to a coated mold and electroplated. NIL Technology’s first commercial nano patterned injection mold was sold in 2014 to mold a package with a hologram.

NIL Technology’s nano imprint lithography technology applies nano patterns directly to an existing non-planar injection mold before molding. The company’s first commercial nano-structured mold was sold in 2014 to mold a hologram-like pattern onto a package.

NIL Technology’s nano imprint lithography technology applies nano patterns directly to an existing non-planar injection mold before molding. The company’s first commercial nano-structured mold was sold in 2014 to mold a hologram-like pattern onto a package.

NANO 4 U Group in Karlsruhe, Germany, and Sarnen, Switzerland (www.nano4u.net), founded in 2008, also directly builds nano structured steel molds, not nickel shims. Its steel molds can form more than a million parts “without severe quality reduction of the nano-structured end products,” NANO 4 U says. Patent-pending technology applies a surface onto an existing steel mold, and then etches into the surface to create nano features. The company’s first commercial application of the technology in an injection mold was in 2009. Main applications are hologram-like logos for branding and authentication in food, pharmaceuticals and medical devices.

NANO 4 U has patent-pending technology to etch nano structures like this holographic logo onto a coated steel injection mold, allowing over a million parts to be molded. Electroplated plastic shims with nano details can mold only a few 100,000 parts.

NANO 4 U has patent-pending technology to etch nano structures like this holographic logo onto a coated steel injection mold, allowing over a million parts to be molded. Electroplated plastic shims with nano details can mold only a few 100,000 parts.

Molecular Imprints Inc., Austin, TX (www.molecularimprints.com), founded in 2001 by two professors from the University of Texas, developed patented “Jet and Flash” imprint lithography that ink jets a low viscosity resist onto a silicon substrate. In 2014 Molecular Imprints sold the technology to Canon Inc., Tokyo, Japan, for use in equipment for the semi-conductor industry. Molecular Imprints is now developing other uses for the technology including nano imprint stamps on silicon, targeting lab-on-a-chip and other medical parts.

The EV Group, St. Florian am Inn, Austria (www.evgroup.com), founded in 1980 to build production equipment for semi-conductors, also builds commercial UV nano imprint lithography printers to make nano detailed parts, which can be electroplated into shims. EVG works with CEA Tech-Leti, a nano technology research institute in Grenoble, France (www.leti.fr).

LEAP Co. Ltd., Kanagawa, Japan (www.leap-leap.co.jp), founded in 2000, worked with Waseda University in Japan to develop patent pending “self-assembled monolayer” surface technology, or SAM, which covers surfaces with nano holes or pillars with high aspect ratio.

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First Coex Microcapillary Film Technology

By Jan H. Schut

The world’s first coextruded microcapillary film was reported by Dow Chemical Co., Midland, MI (www.dow.com) at the Society of Plastics Engineers’ recent ANTEC conference in Orlando, FL (www.4spe.org) in March. The films are made by coextruding microscopic parallel threads in the machine direction in a film matrix.

Dow associate research scientist Wenyi Huang presented the “Effect of Rheology on the Morphology of Coextruded Microcapillary Films,” showing how different viscosities and different processing conditions affect microcapillary structure and describing some of the unique films that can be made.

Huang’s paper doesn’t say what the benefits of microcapillary film might be, but two recent Dow patent applications give clues. Depending on processing parameters and what resin or other material is pumped into the microcapillaries, they could be used to heat, cool, insulate, or even strengthen film.

The idea first surfaced in a 2005 PhD dissertation by Bart Hallmark at the University of Cambridge in the U.K. (www.cam.ac.uk), who put hollow microcapillary channels in the machine direction in monolayer extrudate. Dow licensed the microcapillary concept from Cambridge, but upped the ante by creating its own patent-applied-for film die and coextruding a second polymer into the microchannels.

The Cambridge and Dow dies are conceptually similar—both use hollow tubes to create microchannels. The Cambridge Hallmark patent (U.S. Pat. # 8641946) describes a die that forces monolayer polymer around needles, which inject air to make film or profile with hollow channels in the machine direction. Potential applications, described in subsequent Cambridge patent applications, include food products, tear guides in packaging, and medical devices.

Dow, which is the primary plastics licensee, has industrially scaled the die and added a second polymer, coextruded through hollow conduits, which open into the die land for the matrix polymer. A Dow patent application (U.S. Pat. Applic. # 20140113112) says the microcapillaries are at least five microns thick with at least five microns between them.

Dow’s patent-applied-for microcapillary die coextrudes microscopic fibers in the machine direction into plastic film through small round microcapillary pins in the die opening.

Dow’s patent-applied-for microcapillary die coextrudes microscopic fibers in the machine direction into plastic film through small round microcapillary pins in the die opening.

Dow made microcapillary test films with a 38-mm single-screw extruder with a gear pump for the matrix and a 19-mm single-screw extruder for the microcapillaries, testing different combinations of five commercial Dow polyolefins with different viscosities. Huang’s paper gives relative viscosities and processing temperatures of the five polymers. Polymers 1, 2, and 3 process at 200 degrees C; Polymers 4 and 5 process at 130 degrees C. Polymer 1 is higher viscosity than Polymer 2; Polymer 3 is higher viscosity than Polymer 1; and Polymer 4 is 100 times higher viscosity than Polymer 5, which is very, very low molecular weight – nearly Newtonian.

First, Dow tested film made with Polymer 1 in both the capillaries and matrix, coloring the capillary resin black and leaving the matrix natural, so the capillaries are visible. Dow tested different microcapillary extruder speeds. Not surprisingly, increasing microcapillary extruder speed increased the size of the microcapillaries. With the matrix extruder at 15 RPM and the capillary extruder at 25 RPM, capillaries account for 11.1% of the film. At 50 RPM, capillary percentage goes up to 23.1%. Increasing winding speed makes the film thinner and flattens the microcapillaries.

When Dow tested microcapillary films made with the same polyolefin in the capillaries and matrix at line speeds of 3, 6, 12, and 18 meters/min, capillaries were round at 3 meters/min and almost flat at 18 meters/min. But the film surface was smooth regardless of capillary shape.

When Dow tested microcapillary films made with the same polyolefin in the capillaries and matrix at line speeds of 3, 6, 12, and 18 meters/min, capillaries were round at 3 meters/min and almost flat at 18 meters/min. But the film surface was smooth regardless of capillary shape.

Dow then tested Polymer 1 in the matrix and lower viscosity Polymer 2 in the capillaries and with the matrix extruder at 15 RPM ran the capillary extruder at 25 RPM and 50 RPM. Microcapillary content went from 11.0% at 25 RPM up to 19.4% at 50 RPM. With the microcapillary screw at 50 RPM, winding speed was increased from 3 meters/min to 18 meters/min, which flattened the microcapillaries in much the same way as when capillaries and matrix were the same polymer.

Next Dow tested film made with Polymer 1 matrix and higher viscosity Polymer 3 in the microcapillaries and found that microcapillary content dropped to only 2.3% with the capillary screw at 25 RPM and to 18.6% at 50 RPM. Increasing winding speed didn’t flatten higher viscosity capillaries the way it did lower viscosity ones in a higher viscosity matrix or capillaries of the same polymer as the matrix.

The three different polymer combinations also produced films with different surfaces. With Polymer 1 in both matrix and capillaries at winding speed of 18 meters/min, the film surface is smooth. With different viscosity polymers, the film surface is wavy. When capillaries are lower viscosity than the matrix, the film is thinner over capillaries and thicker between them. When capillaries are higher viscosity than the matrix, the film is thicker over capillaries and thinner between them. Waviness is only visible under a microscope, but the wavy surface feels different to the touch, Huang says.

SQUARE PEGS FROM ROUND HOLES

The most unusual finding is that extremely low viscosity capillaries in an extremely high viscosity matrix produce square or rectangular microcapillaries. Dow tested this extreme viscosity mismatch using watery Polymer 5 in the capillaries and Polymer 4 with 100 times higher viscosity in the matrix. The extreme viscosity pair was tested at four capillary screw speeds – 10, 20, 30 and 40 RPM – with the matrix extruder going very slowly at only 5 RPM.

The microcapillaries were rectangular with the capillary screw at 20 RPM and square with the capillary screw at 40 RPM. As capillary screw speed increased, capillaries also took up a much larger percentage of the film. With the capillary screw at 20 RPM, capillaries are 20% of the film. At 40 RPM they’re 42% – almost half!

Dow then wound films with rectangular and square microcapillaries at line speeds of 1.5 and 3 meters/min and found surprisingly that the rectangular and square microcapillaries only flatten slightly at higher winding speeds. Despite being much lower viscosity than the matrix, they retain squarish shapes.

When watery microcapillary resin is paired with 100 times higher viscosity matrix at a capillary screw speed of 20 RPM (a, c) capillaries are rectangular. At 40 RPM (b, d) capillaries are square. When winding goes from 1.5 m/min (a, b) to 3 m/min (c, d), capillaries only flatten slightly.

When watery microcapillary resin is paired with 100 times higher viscosity matrix at a capillary screw speed of 20 RPM (a, c) capillaries are rectangular. At 40 RPM (b, d) capillaries are square. When winding goes from 1.5 m/min (a, b) to 3 m/min (c, d), capillaries only flatten slightly.

What might Dow do with these unusual films? Two recent Dow patent applications give an idea of potential applications, depending on the size and shape of microcapillaries. Patent application (WO2013009538) for “Microcapillary films containing phase change materials” describes filling microcapillaries with “phase change” materials including carnowax in an LDPE matrix. The list of possible phase change materials in the patent application is long, but the patent suggests that they’re used to add or remove heat to or from the matrix polymer. A second patent application describes “Reinforced microcapillary films and foams” (U.S. Pat. Applic. # 20140072776) and suggests that microcapillary coextrusion could create reinforcing fibers in a film or foam in the machine direction, much like pultrusion.

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The Software behind Mega 3-D Printing

By Jan H. Schut

How do you extrude a functional, full-sized car body without a mold? That’s what Oak Ridge National Laboratory in Oak Ridge, TN (www.ornl.gov), set out to do when it developed the world’s first Big Area Additive Manufacturing (BAAM) machine in 2014. BAAM is a giant pellet-fed 3-D printer, which builds parts out of ribbons of nearly molten plastic from a conventional single screw extruder in an enormous build area of 20 feet x 7.75 feet x 6 feet. But given the size of BAAM parts, there were structural challenges in the new layered polymer technology.

ORNL had developed the BAAM machine rapidly working with Cincinnati Incorporated, Harrison, OH (www.e-ci.com), which adapted its commercial laser cutting machine. Cincinnati built the first BAAM prototype in less than three months using its existing gantry-style platform, but replacing the articulated laser cutter with a 1-inch extruder, fed pellets via a flexible pneumatic hose.

The first BAAM prototype had a smaller build area of 157.5 x 78.5 x 34 inches with an extruder that deposited 10 lb/hour. ORNL demonstrated the prototype by building a concept car body, called the Strati (which means “layers” in Italian) designed as part of a contest held by Local Motors, Phoenix, AZ (www.localmotors.com). When ORNL made the first Strati test parts out of 20% carbon-fiber-filled ABS, the beads delaminated in several places. It took three months of R&D and several more part iterations before ORNL had corrected the part design and successfully showed BAAM for the first time at the International Machine Tool Show 2014 in Chicago, dramatically building an entire Strati car during the show.

Oak Ridge National Lab’s unique BAAM 3-D printer extrudes flat ribbons of hot plastic into entire car bodies. The first test parts had delamination issues from micro cracks between layers, which were corrected in later test parts. New software can now virtually test large part designs.

Oak Ridge National Lab’s unique BAAM 3-D printer extrudes flat ribbons of hot plastic into entire car bodies. The first test parts had delamination issues from micro cracks between layers, which were corrected in later test parts. New software can now virtually test large part designs.

The Strati car body reportedly used about 1000 lbs of carbon-fiber ABS, so ORNL wanted a virtual way to simulate part designs to reduce physical test parts. In November 2014, ORNL partnered with AlphaSTAR Corp., Long Beach, CA (www.alphastarcorp.com), an aerospace and automotive software developer, to simulate crack initiation and propagation, residual stresses, and deformation in BAAM part designs.

The resulting “damage and fracture evolution” software was presented by ORNL research staff Vlastimil Kunc and AlphaSTAR chief scientist Frank Abdi at the Society of Plastics Engineer’s recent ANTEC conference in Orlando, FL (www.4spe.org), in March. “What is new is that (AlphaSTAR’s software) will predict if a given part geometry is producible and will be good quality in the end,” Kunc confirms. For people who didn’t attend ANTEC, all papers are available on CD from the SPE for $200 to members and $250 to nonmembers.

MODELING MICRO CRACKS BETWEEN BEADS

ORNL wanted software to be able to simulate an entire car build using the BAAM process in under 24 hours and needed the software by mid-January in time for the North American International Auto Show last January 12-15 in Detroit. “There are ten miles of bead in the Strati car, including many short segments because we need to stop and start printing depending on geometry,” Kunc notes. Extruded bead starts round and is tamped down to flatten it and make it adhere to the layer below. So there was a lot to simulate. AlphaSTAR met the deadline with software that can virtually build a car in only 12 hours on a personal computer.

To develop the new software, AlphaSTAR modified its mature generalized optimizer analyzer (GENOA) FEM-based software and material characterization and qualification (MCQ) code for virtual testing to the BAAM system. GENOA and MCQ had previously won awards from the National Aeronautic and Space Administration in 1999, R&D magazine in 2000, and the U.S. Small Business Administration in 2001 for its novel multi-scale failure prediction.

With BAAM’s layered extrusion process, the MCQ progressive failure-analysis software can simulate what happens to short-carbon-fiber-filled ABS down to micron-scale behavior of fibers, matrices, and their interphases including manufacturing defects like fiber waviness, agglomeration, resin rich areas, void shapes and sizes, and prediction of the degraded material’s ultimate strength and stiffness.

For example, “most fibers are oriented in the machine direction as hot bead is laid down, but orientation is never perfect,” Abdi notes. “There are also in-plane random and 3-D random fibers as well as oriented fibers. You have to figure out the effect of every one of them in damage evolution prediction. We had to include the damage evolution of every random fiber in each bead for the car – a total of 350,000 beads in a car – and propagate them to fracture and delamination between beads.”

Longer fibers are generally considered desirable, but if longer fibers are wavy, they can actually be weaker (in modulus and strength saturation) than shorter straight fibers. Longer fibers also create micro voids and porosity, which initiate cracks and can cause delamination.

In addition AlphaSTAR simulated the thermal behavior of BAAM parts, modeling how a multi-layer wall cools, while ORNL measured actual temperatures as a BAAM-layered wall was built. Simulation and testing both showed that as successive hot layers are laid down over cooler layers, the hot upper layers twist, initiating delamination.

Micro cracks, however, are sometimes useful. Micro scale simulation showed that “smaller threshold cracks are needed up to a point to relieve thermal stress accumulation and later disappear, so we had to determine threshold crack size,” explains Abdi. “MCQ determines what failures are caused by defects, environmental factors, and manufacturing, while GENOA predicts where, when and why damage occurs.” GENOA found, for instance, that putting a cover over the BAAM build area to keep heat in reduces delamination between layers, whereas heating the build platform did little to reduce cracking.

AlphaSTAR modified its GENOA and MCQ software to simulate ORNL’s Big Area Additive Manufacturing process and test part designs virtually. The new software can simulate building an entire car in 12 hours on a PC and should speed the development of large parts.

AlphaSTAR modified its GENOA and MCQ software to simulate ORNL’s Big Area Additive Manufacturing process and test part designs virtually. The new software can simulate building an entire car in 12 hours on a PC and should speed the development of large parts.

The new software starts with a stereo lithography standard tessellation language (STL) file of an object. Slicer software, developed by ORNL, takes the STL file and slices the object into horizontal layers to generate a machine “G code” or tool path for the 3-D printer to build the part. GENOA then makes a geometric FEM mesh of the part design, which MCQ software uses together with Abaqus solver software from Dassault Systemes, Velizy Villacoublay, France (www.3ds.com), to simulate and correct potential material failures in the part design. ORNL uses MCQ together with the Abacus solver, but AlphaSTAR says its MCQ solver can also be used alone for failure simulation.

“The GENOA, MCQ, and Abaqus software conduct progressive failure analysis and combine those results to predict structure/component behavior based on the physics and mechanics of the materials and the impact of the manufacturing process,” AlphaSTAR’s Abdi explains. “Finally, the software predicted the structural performance under service load – acceleration equal to the centripetal acceleration of the Strati car going 68 km/hour around a curve with a radius of 350 meters.”

MCQ’s multi-scale FEM software has simulated BAAM printed parts down to microscopic scale. Since 2006, MCQ software can also simulate material behavior even smaller down to nano scale, which AlphaSOFT says is the first “de-homogenized” or random damage simulation on a nano molecular scale, though ORNL hasn’t tested the BAAM process that small.

Cincinnati has reportedly sold four of the first size BAAM machines already, including ones to Local Motors, SABIC Innovative Plastics, Exton, PA (www.sabic-ip.com) for material design, and an aerospace company. An even bigger BAAM printing machine, expected to deposit up to 100 lb/hour, will be available for testing in ORNL’s laboratory by midyear. So additive manufacturing could well become a whole new way to build large car and aerospace parts faster, better, less expensively and with much less inventory than they are built today.

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Trolling for New Technology at ANTEC 2015

By Jan H. Schut

The first two pellet-fed 3-D printers take the spotlight at the Society of Plastics Engineers (www.4spe.org) ANTEC 2015 Annual Technical Conference March 23-25 in Orlando, FL. Both are based on existing machine technology—one on extrusion, the other injection molding. They aren’t brand new–they were announced and demonstrated over the past two years at several major international shows. But they’re going commercial now, which is where they get interesting.

Oak Ridge National Laboratory in Tennessee (www.ornl.gov) partnered with machine builder Cincinnati Inc. in Ohio (www.e-ci.com), to develop the first Big Area Additive Manufacturing machine (BAAM) with enough build space for car bodies. It’s based on Cincinnati’s gantry-style laser cutting machine, but replaces the articulated cutter with a 1-inch 14:1 L/D extruder.

Arburg GmbH + Co KG in Germany (www.arburg.com) is also presenting its pellet-fed Freeformer additive manufacturing in the U.S. for the first time, based on injection molding. Build area is only 9 x 5.1 x 9.8 inches, but with two pellet-fed components, it targets complex functional production parts. (For news on smaller 3-D printers, see this blog Oct. 27, 2014.)

Other news at ANTEC includes co-ex films with unusual micro features, nanofoams of engineering polymers, potential algal route to flame retardancy, and new ways to recover high-value plastics from durables. Because ANTEC is collocated this year with the triennial NPE 2015: The International Plastics Showcase, March 23-27 (www.npe.org), processors can first learn about new technology at ANTEC and in several cases see it running next door.

The letter and number in brackets after the title of an ANTEC paper indicate the day of the week and session when it’s given, e.g., [M8] is session 8 on Monday, March 23. Session papers are available to non-attendees from the SPE for $200 to members and $250 to nonmembers. Plenary speeches, new technology forums, and graduate posters, however, aren’t on the CD, so you’ll have to go and listen up!

 

FIRST PELLET-FED 3-D PRINTERS

Breaking Barriers in Additive Manufacturing [T29 New Technology Forum] by Lonnie Love, senior research scientist for automation, robotics and manufacturing at Oakridge National Lab. The first BAAM machine deposited 10 lb/hour of plastic with a build area of 157.5 x 78.75 x 34 inches. The next size deposits 38 lb/hour with a whopping 240 x 93 x 72 inch build area, and it’s planned to go up to 100 lb/hour. BAAM’s gantry-mounted x,y moving extruder is fed pellets by a flexible pneumatic hose and deposits a continuous bead of semi-molten plastic onto a build table with z movement up and down. BAAM was launched last September at the IMTS 2014 show in Chicago, building a small concept car during the show. Next ORNL “printed” a reproduction Shelby Cobra sports car for the North American International Auto Show in Detroit in January with a body of 20% oriented carbon-fiber-filled ABS. Cincinnati has sold four machines already.

Oak Ridge National Lab took only eight months to convert Cincinnati Inc.’s gantry-style laser cutting machine into the world’s first Big Area Additive Manufacturing machine with a build area of 20 x 7 ¾ x 6 feet. At the IMTS 2014 show, it built a concept car during the show.

Oak Ridge National Lab took only eight months to convert Cincinnati Inc.’s gantry-style laser cutting machine into the world’s first Big Area Additive Manufacturing machine with a build area of 20 x 7 ¾ x 6 feet. At the IMTS 2014 show, it built a concept car during the show.

Modeling of Large Scale Fused Deposition Modeling with Reinforced Plastics [W29] by Vlastimil Kunc, research staff at ORNL, describes how large functional parts are simulated. The design starts as a CAD file, is converted into horizontal slices in sterolithography, and finally converted into instructions for the tool path that deposits the plastic bead to build a part. The deposition process is simulated using a finite element tool developed in collaboration with AlphaSTAR Corp., Long Beach, CA (www.alphastarcorp.com), because existing FEM software couldn’t handle the massive calculations. Simulating thermal stresses to prevent cracking and warping of such large parts during cooling is especially complex.

Injection Molding without a Mold: Arburg Plastic Freeforming for Additive Manufacturing of One-of-a-Kind Parts and Small Batches, plenary speech by Heinz Glaub, managing director of technology and engineering at Arburg presents its Freeformer, which plasticizes pellets based on injection-molding. Freeformer feeds two components to a stationary discharge unit with special nozzles that deposit tiny droplets of plastic using high-frequency piezo technology (at 60-200 Hertz). Droplets fuse to form a part on a precisely controlled x,y,z moving carrier. At NPE 2015, two two-component Freeformers are expected to mold a TPU part and a part with an articulated joint using a water soluble support polymer that’s removed easily afterward in a water bath.

Arburg Plastic Freeforming–New Industrial Additive Process [T29 New Technology Forum] by Oliver Kessling, manager of the plastic freeforming department at Arburg, explains the process with focus on materials and applications. The two-component Freeformer can build parts with hard and soft materials, two colors, or a primary and support polymer, allowing complex part geometries with overhangs and undercuts that couldn’t be injection molded. Five published patent applications give an idea of how complex 3-D parts could be produced.

Arburg’s Freeformer plasticizes pellets based on injection molding, building parts with tiny fusing droplets on an x,y,z moving table. A two-component Freeformer can mold hard/soft parts, two colors or a primary and support polymer for complex parts that couldn’t be molded before.

Arburg’s Freeformer plasticizes pellets based on injection molding, building parts with tiny fusing droplets on an x,y,z moving table. A two-component Freeformer can mold hard/soft parts, two colors or a primary and support polymer for complex parts that couldn’t be molded before.

 

NOVEL FILMS AND OTHER EXTRUSION NEWS

Effect of Rheology on the Morphology of Coextruded Microcapillary Films [M8] by Wenyi Huang, associate research scientist, The Dow Chemical Co., Midland, MI (www.dow.com). A new patent-applied-for die (WO2013009538) coextrudes micro channels in the machine direction filled with a second polymer in a matrix polymer layer. Size and shape of microcapillary threads varies by the comparative speeds of the two extruders and the viscosities of the two materials. If the microcapillary resin is much lower viscosity than the matrix, initially round capillaries become square. A decade ago the University of Cambridge in the U.K. patented film with hollow microcapillary channels, but not a second polymer.

Triple Shape Memory Materials Fabricated by Forced Assembly Multi-Layer Film Extrusion Technology [M26] by Shanzuo Ji, doctoral student at Case Western Reserve University in Cleveland, OH (www.case.edu). Case’s nanolayer multiplication die technology forces the assembly of three polymers with different thermal transition temperatures (PU/EVA/PVAc) to make a 257-nanolayer, triple-shape-memory film with better properties than traditional shape memory alloys. Case previously produced dual shape memory materials by forced layer assembly.

Integrated Waste Heat Utilization for Extruder Barrels by Interconnection of Fluid Streams [M28] by Christoph Ketteler, research assistant, University of Duisburg-Essen, Germany (www.uni-due.de). Instead of heating an extruder with electric heater bands and cooling with fans, this energy-saving concept simulates a barrel with two discrete oil loops, one heated, the other cooled, and bypasses for each temperature zone, thus applying heat and cooling directly into the barrel. The next step is to build a lab model.

Uni-Duisburg

 

NANO FOAM AND NANOFEATURE MOLDING

Solid-State Thermoplastic Nanofoams via a Novel Low-Temperature Saturation Pathway [M36] by Huimin Guo, doctoral student at the University of Washington in Seattle (www.washington.edu). Few polymers allow nanocellular foams with cells >100 nm, but new patent-applied-for technology (WO2014210523) nanofoams PC, PMMA, and PSU by saturating the polymer in liquid CO2 at very low temperature (-30 °C) under high pressure, then molding it at over its Tg. This makes PC and PSU nanofoams with 20-30 nm cells and 60% and 48% void space respectively, and PMMA nanofoam with 30-40 nm cells and 86% void space. The university previously commercialized solid-state microcellular foamed PET by saturating it in gaseous CO2 at room temperature under high pressure and molding it at over its Tg.

Injection Molding of Nano-Features: a Study on Filling and Birefringence [M9] by Srini Vaddiraju, senior project engineer at Corning Inc., Corning, NY (www.corning.com), reports an unconventional injection molding technique for optical parts with very low birefringence for Corning’s Epic sensor, used to test sensitive living cell reactions. Injection molding of the sensor substrate replaces a more expensive multi-step coating process on glass. The patent-applied-for injection molding (WO2013148630) is described as using “a fan gate that spans the entire length of the substrate” and 30% of the width. The unheated runner also has a dish-like melt reservoir to keep injection pressure uniform across the wide fan.

 

NEW BIO-BASED MATERIALS AND COMPOSITES

Development of Eggshell Powder Masterbatch for Food Trays [T2] by Yoshihisa Sumita, CEO, Hinode Resin Industry Co. Ltd., Tokyo, Japan (hinode@hinoderesin.jp). Egg shell powder is a source of calcium in food supplements. But when waste eggshells were tested as a 30% mineral filler for molded PP food trays, the compound smelled of sulfur. Hinode found that compounding and molding at the lowest possible temperature for PP avoided the odor problem.

Novel Fire-Resistant Renewable Materials Derived from Freshwater Algae [W25] by Gary E. Wnek, professor at Case Western Reserve University, Cleveland, OH (www.case.edu). The first presentation based on four years of R&D on a species of inherently fire-resistant algae found in Lake Erie. The algae are cellulose-based, but coated with silica diatoms. The next step is to use this discovery to develop environmentally friendly flame retardants for commodity plastics.

Vegetable-Based Copolymers Based on Blend of Acrylated Epoxidized Soybean Oil and Tung Oil [M1] by Samy Madbouly, professor at Iowa State University in Ames (www.iastate.edu). Soy bean oil modified with methacrylates and blended with tung oil as a reactive diluent makes a highly cross-linked copolymer. Described in a 2014 master’s thesis by Harris Handoko, copolymers range from brittle with no tung oil to tough and rubbery with 50%.

Compatibilizing and Toughening of an Immiscible Polyphenylene Blend via Reactive Mixing [M19] by Sayantan Roy, research scientist at Baker Hughes Inc., Houston, TX (www.bakerhughes.com). A patent-applied-for reaction (WO2013077956) combines immiscible PPS and PPSU into a hybrid polymer blend with a single glass transition temperature and the toughness of PPSU. The new material targets downhole sealing applications in oil wells.

 

NEW TECHNOLOGIES TO RECYCLE DURABLES

Rubber Devulcanization Using a Planetary Extruder [T32] by Michael Batton, process manager, Entex GmbH, Bochum, Germany (www.entex.de). Entex owner Harald Rust’s new technology (U.S. Patent Applic. # 20130023639) uses a specific configuration of planetary spindles around a central spindle with precise heating and cooling profiles to break the cross-links in recycled rubber mechanically, so it can be processed again.

Devulcanization of Waste EPDM Rubber from Post Industrial Scrap Using an Ultrasonic Twin-Screw Extruder: Effect of Screw Design [graduate poster] by Hui Dong, graduate student, University of Akron, Akron, OH (www.uakron.edu), presents the first ultrasonic twin-screw devulcanizing of EPDM. When a twin-screw extruder is tested at zero to 13 um of sonic amplitude, it recycles EPDM with higher tensile strength and elongation at break, but lower modulus and viscosity with 13 um of vibration than with none.

Plastics Recovered from Shredded End-of-Life Vehicles [W26] and Plastics Recovered from Shredded Waste Electrical and Electronic Equipment [W26], both by Brian Riise, R&D director at MBA Polymers Inc., Worksop, Nottinghamshire, U.K. (www.mbapolymers.com). MBA’s U.K. plant uses the latest patent-applied-for multi-stage technology (U.S. Patent Applic. # 20140231557) to recover plastics from shredded automobiles. MBA plants in Austria and China recover plastics from shredded waste electrical and electronic equipment for sale into high value products. Only a handful of other plants in the world do anything similar.

MBA polymers

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Whatever Happened to Induction Heated Barrels?

Jan H. Schut

Induction heated barrels are alive and well, but hard to get. The world’s first commercial induction heated barrels were launched by Nordson Xaloy Corp., New Castle, PA (www.xaloy.com) at the K 2007 Show in Germany. Called nXHeat, Xaloy’s patented barrels (U.S. Pat. # 8007709) had compelling advantages, reportedly using roughly 55% less energy than even insulated barrels with resistance heater bands. A 2008 ANTEC paper by Xaloy and Sabic Innovative Plastics, Pittsfield, MA (www.sabic-ip.com), also reported “50% reduction in part weight variability, 25% reduction in dimensional variability,” shorter cycles, and lower maintenance.

When Xaloy launched induction heated barrels in 2007, they offered compelling benefits vs. conventional heater bands: big energy savings, better part quality, cooler operation, and lower maintenance. But induction cost five times more than heater bands.

When Xaloy launched induction heated barrels in 2007, they offered compelling benefits vs. conventional heater bands: big energy savings, better part quality, cooler operation, and lower maintenance. But induction cost five times more than heater bands.

Induction is used industrially to melt and temper metals and sinter ceramics. It generates electro-magnetic waves in electrically conductive materials like metals (not in non-conductive plastic). A twisted induction cable, known as a Litz winding, uses low voltage, high amperage, and very high alternating frequency (20-40 kHz) to pulse oscillating eddy currents into a metal object, heating it from outside in. Patents on induction heated barrels go back to the 1940s, but induction wire wasn’t as efficient then, so they weren’t commercialized. Three Japanese machine builders also developed induction barrels in the early 2000s, but didn’t commercialize them.

Xaloy’s induction barrels use a coiled Litz wire in a sleeve, wrapped around the barrel outside of the foamed barrel insulation. Induction heat requires a generator for the specialized high frequency power supply and expensive controls for the pulsing voltage and phase supply. Temperature controls shut the current on and off rapidly, responding to temperature sensors in the barrel, which are installed closer to the melt than sensors for heater bands. Coils are individually controlled, so if one fails, they can be replaced easily without shutting the machine down. All in all, nXHeat cost five times more than conventional resistive heater bands. Even so, Xaloy expected payback from energy savings in 1.5 to 2 years for machines over 400 tons.

In 2008-2009, several injection molding machine makers supported Xaloy’s induction barrels as options. Ferromatik Milacron Maschinenbau GmbH, Malterdingen, Germany (www.ferromatik.com), showed it in-house in 2008 on an EC-300 injection molding machine forming caps and sold a couple of dozen packaging machines with hybrid induction barrels. To keep cost down, Ferromatik put induction only on the feed zone, where heat demand is highest. At NPE 2009 in Chicago, KraussMaffei AG, Munich, Germany (www.kraussmaffei.com), and Engel Austria GmbH, Schwertberg, Austria (www.engelglobal.com), also offered Xaloy induction barrels as options on their energy-saver machines.

Because of cost, Ferromatik sold induction hybrids in Europe putting induction only where it counted most on feed zones 1 and 2. But cost was still an issue and after six years, Xaloy pulled out of induction technology except for supporting existing customers, mainly automotive.

Because of cost, Ferromatik sold induction hybrids in Europe putting induction only where it counted most on feed zones 1 and 2. But cost was still an issue and after six years, Xaloy pulled out of induction technology except for supporting existing customers, mainly automotive.

But in a recession, expensive barrels were a tough sell, and all three OEMs dropped it. There was also an unspoken liability issue. Because there is no physical limit to how hot induction can make a material, if a temperature sensor on an induction barrel failed and the coils didn’t shut off, they could physically melt the barrel. Resistive heater bands, on the other hand, have an upper limit of around 600 °F, just enough to process PC.

Xaloy sold hundreds of induction retrofits in the U.S. and Europe primarily to high-tech molders with energy-hungry applications for large parts and high temperature plastics. Nordson Xaloy Asia (Thailand) Ltd. in Chonburi, Thailand, sold even more induction barrels in Asia, mostly to large international automotive and electronics molders, where the attraction was both energy saving and better part quality.

In the U.S., molders tried to get energy subsidies for induction retrofits. A custom molder in Wisconsin retrofitted one of the first barrels in 2008 with an energy subsidy and found it saved maintenance and downtime as well as energy. Over the next two years, they retrofitted 24 more presses from 200 to 1000 tons. But often utilities baulked at supporting the new technology. A molder in North Carolina tried hard to get their local electricity co-op to approve subsidies for induction retrofits, but couldn’t and couldn’t afford them. In Europe, hybrid induction retrofits of only zones 1 and 2 of the barrel became more common than full retrofits because of cost.

Then the Chinese jumped in with cheap imitations. There are now over a dozen Chinese induction barrels on the market at very low prices. “Some take induction wire used for cooktops and wind it around barrels, so there is interference between the zones, and no EMF filters to protect workers. Some even put empty boxes along the barrel to look like zone controls, but it’s really one loop, so there’s no energy saving,” complains an Asian salesman for Xaloy.

INDUCTION IS DRIVEN MOSTLY BY KOREA

By 2013 in response to perceived issues with induction (mostly cost), Xaloy launched its SmartHeat barrel technology (U.S. Pat. # 8247747), which heats resistively with fine nickel chrome wires wound directly around the barrel and ceramic coating plasma sprayed over them. Energy saving is similar to induction because SmartHeat barrels also have very low thermal mass compared to heater bands, but SmartHeat costs a third of what nXHeat does.

Xaloy stopped offering induction barrels except to existing customers, for which Xaloy still retrofits 100s of barrels a year. SmartHeat barrel coating is offered to new customers globally. Some big molders in Europe, South America and Asia, however, prefer induction. Logistics are one reason. For a SmartHeat retrofit, a barrel has to be shipped to the U.S., coated and shipped back with a lot of machine downtime. Induction can be retrofitted onto a barrel in place in the factory in a day.

To fill the void left with Xaloy pulling back from induction, the Korean government stepped in to ensure a supply of reliable induction barrels. At the Koplas 2013 plastics show in Seoul, Korea, Purmi Co. Ltd. in Seoul introduced Eco-heater induction barrels from ECO-nomical Heater Co. also in Seoul with Korean government support. Basco Barrel Screw Co. in Seoul (bascojoo@yahoo.co.kr), Xaloy’s long-time Korean rep, represents Eco-heater, which has developed smaller induction units than Xaloy, down to 6 kW vs. 8 kW for Xaloy’s smallest.

Basco/Eco-heater barrels are sold primarily to Korean customers. According to published reports, a dozen Eco-heater barrels went to Samsung Group (www.samsung.com), including one for a 4000-ton Mitsubishi press in Kuang-Ju, Korea, and one for a 3000-ton JSW press to mold bumpers also in Korea. Five Eco-heater barrels went to Hyundai Mobis Co. (www.hyundaimotorgroup.com), including one for a 2000-ton LS Mtron press in A-San, Korea.

To fill the void with Xaloy pulling out of induction, the Korean government supported developing an alternative source of reliable induction retrofits from Eco-heater in Korea. Basco, Xaloy’s long-time Korean representative, is Eco-Heater’s agent, but only for Korean companies.

To fill the void with Xaloy pulling out of induction, the Korean government supported developing an alternative source of reliable induction retrofits from Eco-heater in Korea. Basco, Xaloy’s long-time Korean representative, is Eco-Heater’s agent, but only for Korean companies.

Eco-heater/Basco induction barrels have also gone to Korean companies outside of Korea to Samsung plants in Poland, India, Mexico and China. Ninety Eco-heater induction barrels went to LG Electronics Inc. (www.lg.com) in the U.S. for LS Mtron presses from 450 to 1800 tons, plus one barrel for a 2500-ton LS Mtron press for LG in Mexico. (Injection molding machine builder LS Mtron in Korea (www.lsmtron.com) is a spin-off from LG.) Certainly having a second source for quality induction barrel retrofits is better for molders than having one reluctant source. But can molders who aren’t Korean and already Xaloy induction customers buy them if they want to? Probably not.

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Molding Paper like Plastic

By Jan H. Schut

If plastics processors haven’t noticed paper bottles yet, they should, because paper bottles popped from nowhere four years ago to create a whole new market for paper. Four years ago, two small entrepreneurial companies outside of the packaging industry separately launched patented but similar paper bottles almost simultaneously. These weren’t folded paper cartons, but molded clamshells shaped like glass or plastic bottles. Paper bottles started with milk in local outlets and now package detergent, wine, and cat litter for mass markets, potentially challenging glass and plastic, though plastic is minimally involved for lining and closure.

Four years ago two startup companies, GreenBottle in the U.K. and Ecologic in California, market tested paper milk bottles for a U.K. Walmart subsidiary and Wholefoods respectively. Today paper bottles carry wine, detergent, and kitty litter to mass markets.

Four years ago two startup companies, GreenBottle in the U.K. and Ecologic in California, market tested paper milk bottles for a U.K. Walmart subsidiary and Wholefoods respectively. Today paper bottles carry wine, detergent, and kitty litter to mass markets.

GreenBottle Ltd., originally in Woodbridge, Suffolk, U.K., a startup in March, 2006 (which went into voluntary bankruptcy in February 2014), and Ecologic Brands Inc., Oakland, CA (www.ecologicbrands.com), a start-up in 2008, thermoformed half bottle shells out of paper pulp using vacuum, heat and pressure, then glued the halves together around a thin plastic liner, welded to the bottle opening. Paper is the mechanical support with a thin film lining.

GreenBottle founder and inventor, Martin Myerscough, got his idea for paper bottles from a paper-mache-covered balloon his son made as a craft project. Ecologic founder and inventor, Julie Corbett, got her idea from the molded recycled fiber tray her iPhone was packed in. Molds for GreenBottle’s patent-applied-for technology (U.S. Pat. Applic. # 20130213597) were developed with RTS Flexible Systems Ltd. in Manchester, U.K., now part of Brooks Automation Inc. (www.brooks.com). Molds for Ecologics’ patented technology (U.S. Pat. # 8430262) were developed with DW Product Development Inc., Ottawa, Ont. (www.dwcanada.com).

The basic technology isn’t new. Wood fiber has been pressure formed with two-sided molds into smooth paper plates for over 100 years, but compressing paper pulp hard enough to fuse it into a rigid bottle is new. There are three types of pulp forming. Type 1, slush molding, forms rough parts like heavy walled corner protectors. Type 2, transfer molding, forms thinner parts like packing trays, egg cartons, and cup holders. Both use single-sided vacuum molds to dewater pulp. Type 3, pressure or thermoforming, makes paper plates, clamshells and some paper bottles using two-sided molds. One side is fine mesh with vacuum; the other side applies heat and pressure to fuse fibers and increase stiffness.

GreenBottle used virgin paper fibers for milk bottles and recycled kraft liner shavings for wine bottles. Ecologic uses 100% recycled paper for all its bottles—70% recycled kraft cardboard, 30% recycled newspaper. (kraft paper has longer fibers than newspaper.) After use, paper bottles from both companies can be pulled apart and recycled with paper again. Non-barrier film liners can be recycled with grocery bags; barrier pouches from wine bottles cannot. There aren’t enough paper bottles in the market yet to know how many consumers will figure the recycling out and actually do it. But even if they don’t, paper bottles are distinctive and have boosted sales significantly in market tests.

GreenBottle’s paper bottles were first market tested in 2009 for low fat milk from Marybelle Dairy, Walpole, Suffolk, U.K. (www.marybelle.co.uk). Then in January 2011, Asda Stores Ltd. (www.asda.com), a supermarket chain belonging to Walmart (corporate.walmart.com), tested GreenBottle paper bottles for milk from Trewithen Dairy, Lostwithiel, Cornwall, U.K. (www.trewithendairy.co.uk). The test ran for 18 months with a 200% increase in sales, GreenBottle said. But Trewithin didn’t commercialize the bottles because without Asda’s subsidy, they were too expensive vs. HDPE.

Ecologic’s first market test of paper bottles was for organic skim milk from Straus Family Creamery Inc., Petaluma, CA (www.strausmilk.com), in January 2010 for Whole Foods markets (www.wholefoodsmarket.com) in northern California. It took almost a year to develop half-gallon bottles shaped like Straus’s returnable glass bottles. The test ran six weeks with 72% increase in skim milk sales, Ecologic’s Corbett says. Straus didn’t commercialize the bottle because it requires a pouch filling line, which they don’t have. For the market test, paper bottles were hand filled.

In March 2011, Seventh Generation Inc., Burlington, VT (www.seventhgeneration.com), market tested “4X” concentrated laundry detergent in 50 oz. Ecologic paper bottles also for Whole Foods Markets. These became the first commercial paper bottles in the world, now available nationally in many retailers including Target (www.target.com) stores. Seventh Generation also sells 4X detergent in 60 oz. plastic bottles. In 2011, The Winning Combination Inc., Winnipeg, Manitoba (www.winning-combination.com), launched Bodylogix whey protein in molded paper canisters from Ecologic, sold by Walgreen (www.walgreens.com), General Nutrition Corp. (www.gnc.com), The Vitamin Shoppe (www.vitaminshoppe.com), and others.

In May 2011, Tetra Pak International S.A., Lausanne, Switzerland (www.tetrapak.com), commercialized a paper bottle for shelf stable milk with flat sides, rounded corners, and shoulders called “Evero.” Tetra Pak claims 14 patents on it for things like filling machines and injection molded closures that fuse the top, sleeve and neck. Unlike GreenBottle and Ecologic paper bottles, Evero bottles are plastic coated so they don’t look or feel like paper, but Tetra Pak says they can still be recycled with paper. Evero bottles are commercial for shelf stable milk in Russia, Spain, Portugal, and Brazil, Tetra Pak says. The company also claims its 10,000 pack/hour filling line costs 25%-30% less to buy and run than conventional aseptic pouching.

GreenBottle and Ecologic’s paper bottles can be split apart after use and be recycled with paper. The non-barrier liners can be recycled with grocery bags. Tetra Pak’s one-piece molded paper Evero bottles for shelf stable milk can also reportedly be recycled with paper.

GreenBottle and Ecologic’s paper bottles can be split apart after use and be recycled with paper. The non-barrier liners can be recycled with grocery bags. Tetra Pak’s one-piece molded paper Evero bottles for shelf stable milk can also reportedly be recycled with paper.

MORE PAPER BOTTLES ON THE WAY

Paper wine bottles came next and were much harder to make than milk bottles. In November 2013, wine maker Truett-Hurst Inc., Healdsburg, CA (www.truetthurstinc.com), launched Paperboy wine in GreenBottle paper bottles shaped like Bordeaux wine bottles. Paperboy is distributed by Vons stores in California, part of Safeway Inc. (www.safeway.com), and by selected other Safeway stores. Truett-Hurst had a seven-year bottle supply contract with GreenBottle, which moved paper bottle molds from Turkey to Spain and film liner manufacture and bottle assembly from Trewithin to a plant in St. Helens, Merseyside, U.K.

But GreenBottle, the pioneer which sustained the longest development period, had difficulty gearing up for Truett-Hurst’s volume. On February 28, 2014, GreenBottle went into administration under Begbies Traynor LLP, Preston, Lancashire (www.begbies-traynorgroup.com), which sold GreenBottle’s assembly machinery, molds, and IP assets to Depirus Ltd., a new company set up in February, which plans to relaunch paper wine bottles. Truett-Hurst reported a $400,000 loss on GreenBottle’s insolvency.

In April Truett-Hurst, announced a new three-year supply contract with Ecologic for paper wine bottles, renewable for another two years, and market tested Ecologic bottles in Canada. Ecologic had already raised over $20 million in financing and moved into a 60,000 sq. ft. plant in Manteca, CA, in 2013 to mold pulp bottles and liners and assemble them. The company uses three patent-applied-for liner variations, including thermoforming film to fit the bottle. In April 2014, Kruger Inc., Montreal, Quebec (www.kruger.com), a paper producer and recycler, invested $1 million in Ecologic with the right to produce paper bottles in Canada.

GreenBottle (left) developed the first paper wine bottle for Truett-Hurst, launched in late 2013, but declared insolvency a few months later. Ecologic (right) has since developed a similar Bordeaux-style paper bottle for Truett-Hurst’s Paperboy wines with a multi-year supply contract.

GreenBottle (right) developed the first paper wine bottle for Truett-Hurst, launched in late 2013, but declared insolvency a few months later. Ecologic (left) has since developed a similar Bordeaux-style paper bottle for Truett-Hurst’s Paperboy wines with a multi-year supply contract.

The difficulty of making 750 ml paper wine bottles is getting them rigid enough to stack. The wine industry norm is four cases high on a pallet. It is also hard to match filling line speeds for glass bottles, but Truett-Hurst says Ecologic’s paper bottle is close to doing both. The paper wine bottle is also 80% lighter than glass, so trucks can carry more cases. The latest paper bottle development is the first all paper bottle with a paper lid and no plastic lining. Nestle Purina PetCare Co., St. Louis, MO (www.purina.com), launched all paper jugs for 6 and 12 lb sizes of Renew cat litter in PetSmart Inc. (www.petsmart.com) stores on January 2, replacing plastic F style jugs, though plastic jugs are still used for 20 lb. sizes.

Major packaging companies are watching paper bottles closely. In 2011, Pepsico Inc., Purchase, NY (www.pepsico.com), applied for a patent on paper bottle technology (WO 2013/192260) that combines reheat/stretch blow molding with pulp forming. The patent application describes arranging wet fiber sheets in a spiral something like paper mailing tubes, then pushing the bottom of the tube in to form a stable base. An injection molded preform is heated and blown inside the wet paper bottle to squeeze water out, replacing matched metal molds, the patent says. But it’s not clear whether Pepsi’s paper bottle would be recyclable.

The earliest molded paper bottle is probably from Kao Corp., Tokyo, Japan (www.kao.com/jp), a century old cosmetics and chemical company with patented technology for a pulp bottle (U.S. Pat. # 6899793), issued in 2005. Kao used it to mold plastic-coated paper canisters for cleaning powder, which were launched in Japan and won prizes. The patent describes inserting an “expandable pressing member” into a pulp-lined cavity and filling it with liquid to compress the pulp and squeeze water out. But apparently this didn’t exert enough pressure to fuse fibers into a viable container. The packages were later dropped, but could be reintroduced. There are also unresolved patent issues (mostly about the paper bottle closure) between Ecologic and Greenbottle’s successor. Hopefully these can be worked out because the marketplace would be better served by more players than fewer, and there are already a number of directions that paper bottles could take.

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Finally, the First Commercial Thermoformed Bottles

By Jan H. Schut

For decades an incredible amount of inventiveness has been thrown at the challenge of trying to thermoform bottles. The idea was that making bottles out of thin sheet would save 20% to 50% in materials over extrusion blow molding with lower energy, higher output, and easy material and color changes—including barrier—just by changing a roll. Over the years probably a half dozen ingenious technologies were patented, built, announced, and some even exhibited at major trade shows, without ultimately making a commercial bottle.

The string of patents on thermoformed bottles makes fascinating reading. Some are from well-known names in packaging like Hartmut Klocke of the Klocke Group, who applied for a patent on “Thermoforming Packaging” of bottle-like containers in 1981 (German Pat. DE 8135111U1). Others are from relatively unknown inventors like Rudolf Holzleitner, principal of Hol-Pack Verpackungen, Piberbach, Austria (www.hol-pack.at), a processor of PC bottles.

Holzleitner’s patented technology (European Pat. # EP 2091829) resembles twin-sheet thermoforming, but for disposable bottles up to 1.25 liters. One side of the bottle is deep drawn, including the bottle spout. The other side could be flat or half round. Building bottles with unmatched halves opens wonderful design possibilities. The seam between halves could be vertical or horizontal, making two-colored bottles possible horizontally or vertically and even multi-chambered bottles or packs of detachable bottles. Holzleitner got some support from the Austria Wirtschaftsservice Technology and Innovation in Vienna, but not enough to launch the technology, so eventually he let it lapse.

Hol-Pack in Austria invented an ingenious twin-sheet forming technology for up to 1.25 liter bottles. Bottle halves could be formed either horizontally or vertically with novel design options. But the technology failed to attract investors and eventually was dropped.

Hol-Pack in Austria invented an ingenious twin-sheet forming technology for up to 1.25 liter bottles. Bottle halves could be formed either horizontally or vertically with novel design options. But the technology failed to attract investors and eventually was dropped.

Patents for thermoforming large bottles like Holzleitner’s are unusual. The target for most thermoformed bottle technology has been for single portion yogurt and juice drinks as an extension of form-fill-seal machinery. Erca Formseal S.A. in Cortaboeuf, France (www.oystar-group.com), part of Oystar Group in Germany, announced “Open Mold” thermoforming of bottles in 2003, showing it for the first time at the Emballage show in Paris (www.all4pack.fr) in 2010. The patented process (U.S. Pat. # 7585453) reportedly can make 6000-18,000 standard yogurt cups/hour or 9000-16,800 thermoformed bottles/hour with walls 0.7 mm thick for material savings of 20%. The patent describes “a plastic stretching device to reduce the plastic bottom web thickness in the unused thermoforming areas.” But the technology wasn’t in fact material efficient, Erca says, and isn’t being offered now, though research is still going on.

Oystar Erca in France, a maker of form-fill-seal machines, introduced “Open Mold” thermoforming over a decade ago to form small portion yogurt bottles. But the technology wasn’t material efficient and was never commercialized.

Oystar Erca in France, a maker of form-fill-seal machines, introduced “Open Mold” thermoforming over a decade ago to form small portion yogurt bottles. But the technology wasn’t material efficient and was never commercialized.

In 2008, a builder of thermoforming and form-fill-seal machines, Illig Maschinenbau GmbH in Heilbronn, Germany (www.illig.de), got into the market with Bottleform technology, which Illig demonstrated for the first time at Interpack in Dusseldorf, Germany (www.interpack.com) in 2011. A Bottleform BF 70 machine reportedly can make up to 25,000 x 200-ml bottles or cups/hour depending on shape and size, using sheet from 0.4 to 2 mm thick. Bottles can have steep undercuts for necks or even pedestal shapes. The technology can mold partially threaded necks, but the necks couldn’t withstand the torque of screw caps, Illig says, so bottles would be foil sealed and shrink-sleeve labeled. Illig’s process is now also called “Open Mold Forming” because it can thermoform standard cups as well as bottles.

Illig’s technology is a proprietary combination of vacuum forming, pressured sterile air, and plug assist with tooling undercuts to form necks. The BF 70 machine can have up to 20 cavities and use 68% of 26-inch-wide sheet for bottles or for cups. Depth of draw can be up to 5.7 inches with 2:1 draw ratio for bottles from 50 to 200 ml. The machines could be all stainless steel for use with clean, ultra clean or aseptic fillers for Federal Drug Administration approval on food filling lines. Illig’s “Open Mold” forming recently added punch-in-place bottle removal for greater accuracy of bottle lips. Illig hasn’t sold the technology commercially, but says it is in discussion with packaging companies both in Europe and in the U.S.

In 2008 Illig in Germany launched a thermoforming machine for bottles as well as cups, now called “open mold” forming. It combines vacuum forming, pressured air, plug assist and steep undercuts for bottle necks. Illig is in discussions with customers, but hasn’t sold it commercially.

In 2008 Illig in Germany launched a thermoforming machine for bottles as well as cups, now called “open mold” forming. It combines vacuum forming, pressured air, plug assist and steep undercuts for bottle necks. Illig is in discussions with customers, but hasn’t sold it commercially.

FINALLY COMMERCIAL!

Against this backdrop of highly imaginative but ultimately not commercialized R&D, a small startup company in France actually patented, built, and sold machines for what are believed to be the first commercial thermoformed bottles. Agami Technologies in Trappes, France (www.agami-tech.fr), which started in 2009, developed patented film-to-bottle machinery called Roll ‘N Blow (European Pat. # EP 2321113), which doesn’t use tooling undercuts and reportedly saves 30%-50% in material over extrusion blow molding.

The process starts with thin sheet for thermoforming and slits it in the machine direction into strips. The strips are shaped around blow air pipes into cylinders and welded along the open seam to make tubes. Tubes are heated and blown into bottle cavities at low pressure (under 6 bars) and under 150 °C. Because Agami forms bottles from a continuous tube of sheet, not by deep drawing flat sheet, bottle height isn’t limited, and no undercuts are needed. The process can potentially use standard blow mold tooling if the size is right.

The technology is used commercially to make 50-300 ml bottles at 7000-20,000 bottles/hour depending on size and shape, but it could make up to 500 ml bottles, Serac says. Bottles can have foil lids or screw caps and are shrink labeled. The film can also be preprinted before it’s made into bottles.

Serac in France bought start up Agami’s technology to thermoform bottles out of thin sheet. Agami first slits the sheet into strips, and then rolls the strips into tubes, which are heated and blown into bottle cavities. Four machines have been sold for commercial production and one for R&D.

Serac in France bought start up Agami’s technology to thermoform bottles out of thin sheet. Agami first slits the sheet into strips, and then rolls the strips into tubes, which are heated and blown into bottle cavities. Four machines have been sold for commercial production and one for R&D.

Serac Group SAS in La Ferte Bernard, France (www.serac-group.com), a maker of filling and capping machines, initially bought 10% of Agami along with worldwide distributions rights to the machines, which Serac introduced at Interpack in 2011. Serac has sold five machines since, one with two cavities to a U.S. firm for R&D, two machines with four cavities for commercial production in Europe making portion yogurt bottles, and two machines with six cavities, which are being built for a European customer for full production of yogurt bottles. Bottles are made commercially from PS and PP sheet. They could presumably be made from HDPE and PLA sheet too, but these haven’t been tested yet. Six months ago Serac acquired 100% of Agami and plans to introduce the technology for the first time in the U.S. at NPE (www.npe.org) in Orlando, FL, next March.

Two of Serac’s Agami machines are in commercial production in Europe thermoforming bottles in four cavities out of PP and PS sheet for portion yogurt drinks. In the first station, sheet is made into tubes, which are blown into bottles. In the second station bottles are filled and sealed.

Two of Serac’s Agami machines are in commercial production in Europe thermoforming bottles in four cavities out of PP and PS sheet for portion yogurt drinks. In the first station, sheet is made into tubes, which are blown into bottles. In the second station bottles are filled and sealed.

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