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Division Conference Offers Varied Program

“The Polymers, Laminations and Coatings Conference offers something for everybody in the flexible packaging and converting industries this year,” according to Harry Cordatos, the technical program chairperson. “With 22 technical sessions comprising over 100 papers, the technical presentations cover subjects that range from an introduction to rheology to flexible packaging case studies.”

The Sheraton San Diego Hotel and Marina is the location for the meeting on August 26 — 30, 2001. “The large audience of raw material manufacturers, converters, and end users will have many chances to network with their peers,” according to Cordatos. “People at past conferences have told us that they frequently find solutions to their problems while attending Polymers, Laminations and Coatings Conferences. The four panel discussions are especially good venues for a helpful exchange of information.” Another popular networking occasion is the conference reception. This event in San Diego will be a “Pool Luau At Conference End” (PLACE) held on Wednesday, August 29, from 6 — 10 PM. The outdoor location will allow meeting with other conference attendees for food and fellowship while watching the setting sun in the popular San Diego climate.

Cordatos noted that all events at the Polymers, Laminations and Coating Conference provide the following opportunities to attendees:

  • Network with people who share common interests
  • Expand and refresh knowledge through available learning resources
  • Discover solutions to operating issues.

The New Technology Showcase at the 2001 Polymers, Laminations and Coatings Conference will feature additional presentations in response to suggestions from past attendees while retaining the successful format of previous years. Company spokespersons will offer five-minute presentations on developments commercialized within the past year. Following this event, the Table Top Reception is an opportunity for suppliers to present information on their latest research and product applications.

Panel Discussions

The panel discussions at the conference start with brief introductory remarks by the panelists on their specific areas of expertise. Following their presentations, audience members can ask questions to learn additional information. The titles of the four panel discussions are “Ask The Converter,” “The Web Is The Place To Be,” “Barrier Packaging: End User Perspectives,” and “What Do They Know: A Converter's Panel.” In the first panel, flexible packaging converters with diverse backgrounds and disciplines will present an interactive discussion of converting as it is today and as they envision it developing in this century.

The panel on “The Web Is The Place To Be” will explore the roll of the Internet in converting today. Some areas of discussion will be development and use of a web site by a converter to enhance their business, working with a web site development company to compliment business, and working with web sites of trade publications to find information to buy equipment and advertise products. The barrier packaging panel will discuss the opportunities and challenges in this rapidly growing and important area of packaging. Clifford J. Maxwell of Mica Corporation will moderate the fourth panel consisting of five panelists from prominent converting companies.

Basic Information

This Polymers, Laminations and Coatings Conference will offer five sessions highlighting basic information. These sessions provide an excellent venue for newcomers to the industry to learn important information and for others to review previously learned information. The first technical session of the conference on Monday, August 27, will cover “Extrusion Basics: Plus!” Seven speakers will provide information on “Fundamentals Of Polyethyene,” “ A Brief Introduction To Rheology,” “Specialty Sealants For Extrusion Coating And Films,” “Primers For Extrusion Coating,” “Extrusion Coating Polyester,” “Introduction To Extrusion Coating Equipment,” and “The Basics Of Blown Film Extrusion.”

The second basic session is “Machinery Basics.” In six technical papers, the audience will learn about “Fundamentals Of Adhesion Promotion: Corona, Flame, And Ozone,” “Fundamentals Of Cast Film Machinery And The Cast Film Process,” “A Comparison Of Cast And Blown Film: Process And Properties,” “An Introduction To Coextrusion Systems,” and “Fundamentals Of Blown Film Systems.”

Amy B. Hitchock of Eastman Chemical Co. will chair the session on “Resin Basics.” The speakers will cover ethyl methyl acrylate copolymers, ethyl butyl acrylate copolymers, high pressure low density polyethylene, gas phase linear low density polyethylene, and single site metallocene plastomers. The session on basics for barrier materials will feature an overview presentation on flexible packaging by Dean A. Zimmerman of Procter & Gamble Co. Other papers will discuss permeation measurement, use of ethylene vinyl alcohol resins in modified atmosphere packaging for fresh meat, and coextrudable tie resins. A session on “Additives Basics” will offer papers covering colorants, metal stearates, and UV stabilizers.

New Materials

A feature of the technical session on “New Barrier Materials” is the presentation by Keith Donaldson of Engineered Materials, Inc., entitled “A New Permanent ESD And Corrosion Resistant Barrier Packaging Material.” His paper will discuss a new active barrier material for electrostatic discharge and corrosion protection. The new materials are reactive polymers that consist of a blend of polymer resins covalently bonded with stable solid-state additives.

The session on “UV/EB Materials For Flexible Packaging” will have a paper on “EB Curing In Flexible Packaging” by Anthony J. Bean of Sun Chemical Corporation. He will present recent advances in electron beam curing chemistry and equipment and describe some uses and areas of impact on flexible packaging. Stephen C. Lapin of Northwest Coatings Corporation will discuss “Electron Beam Curable Laminating Adhesives For Flexible Packaging.” He used designed experiments to identify optimum electron beam laminating adhesives compositions for OPP, metallized OPP, PET, and LLDPE films. “The Green Benefits Of UV/EB Technology” by Elmer Griese of Cork Industries, Inc., will show how UV and EB technology applied to the graphic arts industry offers “green benefits” for environmental protection and conservation by eliminating pollution, creating energy efficiencies, and minimizing waste and recycling materials.

The session on “Advances In High Barrier Packaging” will have six papers on the latest developments in this area of flexible packaging. “Use Of Cyclic Olefin Copolymers For Flexible Barrier Packaging” by Arno Wolf of Celanese AG-Ticona will discuss how cyclic olefin copolymers as a blend component can dramatically improve the performance of polyethylene films in bags, pouches, and other packaging applications. “Use Of Oxygen Scavengers In Flexible Packaging: An Overview And Cast Studies” by Brad D. Rodgers of Chevron Phillips Chemical Co. is an exploration into the types of scavenging techniques with a comparison of their performance. It will give examples of using these products with their advantages and disadvantages. Case studies will illustrate the effectiveness of using oxygen scavengers in packaging.

Interactive Workshop

Dante F. Ferrari of AT Plastics, Inc., and Virginia P. Cushing of Mica Corp. will lead an interactive workshop called “Flexible Packaging Case Studies.” The session will run an entire day with a format emphasizing audience interaction that is new to the Polymers, Laminations and Coatings Conference. In the session, David R. Roisum of Finishing Technologies, Inc., will make two presentations: “Secrets Of A Level Process And Product” and “Baggy Webs: Making, Measurement, And Mitigation Thereof.”

Raymond Siegel of Cork Industries, Inc., will talk on “Aqueous Coatings and Adhesives”, and William R. Myer of Geometric Machine and Design will address “Solventless Laminating Winding Problems.” The session will also include presentations by R. Duane Smith of Black Clawson Converting Machinery on “Web Handling and Winding,” Roy B. Cannon of Teknek on “Contamination Control In A Production Environment,” Janevieve A. Jones of AT Plastics, Inc., on “There Can Be ‘Too Much Of A Good Thing’ Leading to Widespread Adhesion Problems,'” and Bruce W. Foster of Mica Corp. on “The Case Of The Wrong Thermal-Stability: How Two Problems Were Solved With A Single Lab Test.”

A session on “Styrenic Materials” will feature a presentation entitled “Fundamentals Of Styrene-Butadiene Copolymers In Flexible Packaging” by Alex Keane of Chevron Phillips Chemical Co. He will discuss how these materials provide value in packaging to stand out on the consumer shelves while effectively protecting the product inside. By illustrating the properties of the material, he will outline its advantages for flexible packaging markets. Other papers in this session are “Processing Styrene-Butadiene Copolymers For Blown And Cast Film Applications,” “Employing Styrene-Butadiene Copolymers In Modified Atmosphere Packaging,” and “Special Considerations For Printing On Styrene-Based Substrates.” This session and the session on UV/EB adhesive are first-time offerings at a Polymers, Laminations and Coatings Conference.

Extrusion Topics

The Polymers, Laminations and Coatings Conference is renowned for its comprehensive and informative presentations in the areas of Extrusion Coating and Film Extrusion. The 2001 conference will offer the following sessions in these areas:

  • Extrusion Beyond The Die
  • Innovations In Extrusion Coating
  • Advanced Additives
  • New Materials In Film Extrusion
  • A Technical Potpourri
  • Film Extrusion Troubleshooting
  • Film Processing: Dies And Screws
  • SPE Exchange.

The more than 60 papers in these sessions cover subjects ranging from “Heat Transfer Rolls: Function And Application Relationships” to “Discoloration Resistant Polyolefin Films” in the film extrusion area. “Aqueous Primers That Adhere Extruded Polypropylene To Various Substrates” and “A New High Performance mVLDPE” illustrate the breadth of technical presentations in the extrusion coating area. A paper on “Advances In Polypropylene For Extrusion Coating” will discuss process development studies and recent advancements in resin formulations that have shown that new polypropylene grades can be efficient and economical alternatives to older-generation polypropylenes or polyethylene in many applications. “Functionalization Of Films Through The Use Of Additives” will examine new materials that help overcome some shortcomings and create differentiated film products. These include anti-dust additives that improve packaging appearance and light transmission through greenhouse films, new antifogging additives for greenhouse films, new methods to manipulate light inside a greenhouse to help control plant diseases, and additives that improve oxygen and UV barrier properties for protection of packaged goods.

William G. Todd of Equistar Chemicals L.P. will talk on “Resin Production Techniques And The Effect On Resin Properties.” In a paper on “Effects Of Electron Beam Irradiation On Biaxially Oriented Polyethylene Shrink Films,” Jim Huang of Nova Chemicals Ltd. will discuss polyethylene films produced from the double-bubble process of biaxial orientation that underwent different levels of e-beam irradiation. He will delve into the effects of crosslinking on the macromolecular properties, the effects on the macroscopic film properties, and the effects on heat sealing and shrink wrapping performance.

Jakob Lange of Packaging Laboratory Materials will address the bending stiffness of thin films and laminates through a combined experimental and modelling approach in his presentation on “Modeling And Measuring Bending Stiffness Of Flexible Packaging Materials.” A second paper by the same author on “Understanding Puncture Resistance And Perforation Behavior On Packaging Laminates” will examine the mechanism of perforation in flexible laminates. The paper presents a method to assess experimentally the puncture resistance and the development of such a method using geometry and test parameters for packaging dehydrated culinary products.

“Bridging The Modulus Gap For Heavy-Duty Shipping Sack Blown Films” by Kelly Williams of Equistar will discuss the development of blown film resins that exhibit the toughness properties of LLDPE with the stiffness and tensile characteristics of HDPE. Leonard Cribbs of the same organization will address film structures that exhibit high stiffness with clarity in a mono-layer film. In “Measurement Of Dispersion Quality In Thermoplastics,” Philip Niedenzu of duPont will review four common methods to rate dispersion quality, visual examination, microscopic methods, and pressure rise and screen pack retention. He will review ease of use, cost, and relevance to dispersion quality.

Additional Information

The complete program for the 2001 Polymers, Laminations and Coatings Conference (and registration information) is available at www.tappi.org or from the Tappi Service Line by calling 1-800-332-8686 in the United States, 1-800-446-9431 in Canada, or +1-770-446-1400 from other locations. Send FAX to 1-770-446-6947. Address mail to TAPPI, Box 105113, Atlanta, GA, 30348-5113.

PEER-REVIEWED TECHNICAL PAPERS:

Following are expanded summaries of complete papers that are available on the TAPPI web site at www.tappi.org/public/library.asp

Polylactide: A New Thermoplastic For Extrusion Coating

by Mark Hartmann and Nicole Whiteman
Cargill Dow, LLC
email:
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Application: New packaging systems using polylactide offer excellent adhesive and barrier properties with the added advantage of an environmentally friendly product for disposal in municipal compost systems.

Polylactide (PLA) belongs to a family of aliphatic polyesters commonly made from a series of α-hydroxy acids such as glycolic or mandelic acid. The hydrolysis of these polyesters back to their natural monomers and the subsequent metabolism by natural organisms renders these materials biodegradable in a normal time scale. PLA is not a new material. Due to its biocompatability and biodegradability, it has had use in the biomedical field for many years for applications such as sutures, bone screws, controlled release encapsulation, and tissue scaffolding.

Until recently, the cost of using medical grade PLA for commercial packaging applications was prohibitive. Recent manufacturing advances have yielded PLA polymers from annually renewable sources with comparable costs to other large-scale commodity polymers. PLA is useful in biodegradable films or fibers, packaging markets, and performance applications because of its unique attributes of modulus, FDA GRAS status, heat seal, and barrier properties.

Manufacture

The basic building block of PLA is lactic acid that occurs in two isomeric forms. Bacterial fermentation produces both isomers commercially for use in the food additive and biomedical markets. High molecular weight PLA comes from the fermentation of cornstarch. This lactic acid is condensation polymerized to form a low molecular weight prepolymer that is depolymerized to form the cyclic dimers known as lactide. This lactide is purified by distillation and processed into high molecular weight PLA by catalytic ring opening polymerization.

This PLA yields linear polymers with narrow molecular weight distributions. These linear polymers that lack long chain branching and therefore adequate chain entanglement and melt elasticity have poor process stability. This leads to edge weave, draw resonance, and melt instability during extrusion coating. Modification of the PLA and increasing the amount of branching creates long chain branching that improves chain entanglement and melt elasticity.

Processing

To run on large-scale, commercial extrusion coating lines, extrusion coating resins must have good final physical properties, stability at high line speeds and various temperatures, and good adhesion to the substrate undergoing coating. By rheology modification of PLA, coating on commercial extrusion coating lines at speeds as fast as 600 m/min is possible without severe neck-in, edge weave, or draw resonance.

One aspect of increased line speeds and the drive to increase production coupled with the effect of down gauging polymer coating to decrease costs is the detrimental effect on final coating adhesion. By increasing line speed and decreasing throughput of the polymer web, substantial heat loss from the polymer web occurs with dramatic increases in polymer viscosity. This viscosity increase leads to less film penetration into the fibers and concomitant loss of adhesion between film and paper. Reducing the air gap and increasing throughput can manage web heat loss and control adhesion. One erroneous common solution to solve low adhesion is to increase the temperature of the melt and lower its viscosity. This only causes increased polymer thermal degradation, loss of molecular weight, decrease of melt strength, and narrowing of the process window.

To help alleviate this adhesion problem and improve total coating properties, a coextrusion system using a commercial food-approved biodegradable flexible polyester in a tie layer improves adhesion, ductility, and processing. This coextrusion system allows the coating converter to run both polymers at lower temperatures. This gives a wider processing window and higher quality finished product.

Properties

Due to its polar aliphatic polyester characteristics, PLA brings a unique set of properties to the packaging market. Table I shows the various properties that PLA imparts.

PLA is a high modulus polymer that is comparable to polyester or cellophane and approximately double that of high density polyethylene or polypropylene. This increased modulus and tensile give the excellent deadfold and crimp similar to cellophane. When replacing polyolefins, PLA gives the ability to downgauge either the paper or board substrate or the coating thickness while retaining package strength.

TABLE I - PLA FUNCTIONAL PROPERTIES
Functional Property: Packaging Improvement:
High gloss and clarity Package aesthetics
High tensile and modulus Wet paper strength and ability to downgauge coating
Low COF and high polarity Printability
Deadfold, twist, and crimp Improved folding and sealing
Low temperature heat seal Stronger seals at lower temperatures
Barrier properties Grease and oil resistance
Flavor and aroma properties Reduced taste and odor issues
GRAS status Food contact acceptable
Compostable Low “green” tax

PLA is an inherently polar material due to the basic repeat unit of lactic acid. This high polarity leads to many unique attributes such as a high critical surface energy that yields excellent printability. Another benefit of this polar polyester polymer is resistance to aliphatic molecules such as oils and terpenes. PLA provides coatings that outperform standard polyethylene coatings and are comparable with more expensive fluorine treated paper. These packaging structures have interest for ice cream containers, meat and burger wraps, and other oily and greasy food packaging.

Liquid and juice packaging are also potential applications for PLA. Standard polyethylene coatings alter orange juice flavor over time and sometimes allow migration of printing ink components into the juice. Heat sealing of PLA can use lower temperatures for shorter times while yielding stronger seal and hot tack strength than low density polyethylene. PLA gives stronger hot tack strength that provides faster package filling, higher productivity, and strong final heat seal strengths.

Conclusion

PLA, a new sustainable thermoplastic, brings a unique set of properties to the coating extrusion and packaging markets. The ability to control rheology and polymer architecture provides for processing on conventional extrusion coating equipment without extensive capital improvements. Valued property combinations such as high modulus, high surface energy, excellent performance as a sealant, and excellent barrier to fats and flavor and aroma compounds give the engineer the ability to downgauge or simplify a multi-layer package. The themoplastic PLA made from annually renewable corn feedstock provides an environmentally friendly product for disposal in municipal compost systems.

New Division Officers

Ginger Cushing, Director of Product Management and Technical Service, at Mica Corp. in Shelton, CT, will become secretary of the Polymers, Laminations and Coatings Division in September 2001. A TAPPI member since 1988, she has been very active in the Extrusion Coating Committee of the Division. She currently serves as chairperson of that committee after progressing through all the offices of the committee since 1996. In designating her as the incoming secretary, John Perdikoulias, division chairman, noted, “Ginger is the first person in recent memory who did not skip a chair in the officer rotation on the Extrusion Coating Committee. She has proven herself as an excellent administrator with a definite commitment to the success of the Polymers, Laminations and Coatings Division!”

During her Extrusion Coating Committee activity, Cushing has presented technical papers at many Polymers, Laminations and Coatings Division conferences, symposia, and short courses in the United States and globally. A trademark of her presentations that audiences enjoy is mention of her pet dogs with photographs. At Mica Corp., Cushing has developed and serviced aqueous primers for extrusion coating applications. She has also been active in other specialty aqueous coatings and received a U.S. patent for her work with barrier coatings.

The other new officers of the division who will progress from their present positions are James L. Cooper of Dow Chemical USA, who will become division chairperson; Laurie Beth Tyldesley of Black Clawson Converting Machinery LLC moving into the position of division vice chairperson; and Jeffrey J. Wooster of Dow Chemical USA, who will be second vice chairperson.

Perdikoulias will become past chairperson. Retaining their present positions in the division are Harry Cordatos of Westvaco Corp. as technical program chairperson and Ashok M. Adur of Everest International as scholarship chairperson. John V. Benham of Equistar Chemicals L.P. marketing committee chairperson, and David J. Bentley, Jr., of RBS Technologies Inc., continuing education chairperson, will continue in their roles.

For information about the Polymers, Laminations and Coatings Division of TAPPI, see the web page at www.tappi.org/public/divisions/polymers_laminations_coatings.asp or access the TAPPI web site at www.tappi.org. For the complete papers whose expanded summaries appear in this section, go to the TAPPI web site at www.tappi.org/public/library.asp and click on the logo displayed here.

Telephone inquiries are welcome at the TAPPI Service Line by calling 1-800-332-8686 in the United States, 1-800-446-9431 in Canada, or +1-770-446-1400 in other countries. Send FAX to 1-770-446-6947. Address mail to TAPPI, Box 105113, Atlanta, GA, 30348-5113. Contact ”the PLACE” editor using e-mail at This email address is being protected from spambots. You need JavaScript enabled to view it..


 

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