THE SCIENCE AND TECHNOLOGY
`OF FLEXIBLE PACKAGING
`
`Multilayer Films from Resin and Process
`to End Use
`
`Barry A. Morris
`
`Amsterdam (cid:129) Boston (cid:129) Heidelberg (cid:129) London (cid:129) New York (cid:129) Oxford
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`0002
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`

`

`There are many handbooks available that describe
`plastics and equipment to make multilayer film.
`While these books provide a good list of what is
`possible, they often fail to provide the reader the
`fundamental understanding of why one material is
`favored over another for a particular application,
`or how the film or coating process affects the prop-
`erties. Also,
`these books do not cover how the
`product being packaged and the end use affect the
`film properties.
`Similarly, there are handbooks on packaging tech-
`nology that provide details on the mechanical aspects
`of packaging equipment and outline film structures
`currently in use (at least at the time the book was pub-
`lished). These books fail to explain the principles
`behind packaging equipment from a unit operation’s
`perspective (sealing, thermoforming, and so on). Nor
`do they give the reader a fundamental understanding
`of how to design a packaging structure.
`There are also a few textbooks that provide an
`academic analysis of polymer processes. These are
`typically written at a level beyond the reach or desire
`of most packaging engineers.
`My goal is to create a book that brings the science
`to the practitioner in a concise and impactful way,
`bridging the gap between standard handbooks and
`academic treatises. Using scientific principles, I
`explore (and debunk) some of the myths that have
`persisted in our industry. While discussing key chal-
`lenges in the packaging industry, I provide a critical
`review of the scientific literature as well as practical
`explanations and tips on how to deal with the chal-
`lenge. Too often packaging engineers fail to seek
`out
`the scientific literature. One benefit of this
`book is easy access to this literature, summarized
`in a meaningful way. Finally, the book provides
`insight into why things are done the way they are,
`which makes the work evergreen: the same princi-
`ples can be applied to new packaging applications
`with new materials that are sure to come along in
`the future.
`
`Preface
`
`This book is organized into seven parts and two
`appendices:
`
`1. Introduction
`
`2. Basic processes
`
`3. Material basics
`
`4. Film properties
`
`5. Effect of converting processes on properties
`
`6. End-use considerations
`
`7. Structure Design and Modeling
`
`Appendix A: Writing Guide for Packaging Films
`and Other Multilayer Structures
`
`Appendix B: Examples of Flexible Packaging
`Film Structures
`
`The introduction provides a brief history of pack-
`aging and its benefits to society. It describes the basic
`functions of packaging, the packaging value chain,
`and what is important for each player in the value
`chain. It also introduces the need for multilayer films
`to provide the needs along the value chain in the most
`cost-effective manner.
`Part 2 briefly describes the processes involved in
`the manufacture and use of multilayer films for pack-
`aging. Basic differences between technologies and
`why one may be favored over another for a given
`application are highlighted. Key unit operations and
`processing variables are introduced that affect prop-
`erties, which are described in more detail in subse-
`quent chapters.
`Part 3 introduces resins and substrates commonly
`used in flexible packaging, highlighting important
`properties, applications, and regulatory issues. Chap-
`ters on melt rheology and polymer blending round
`out the basics.
`Part 4 begins the heart of the book, providing
`detailed descriptions and analysis of the key proper-
`ties of packaging films from an engineering and
`
`xv
`
`0003
`
`

`

`xvi
`
`PREFACE
`
`scientific perspective. Drawing from personal knowl-
`edge/experiments and the scientific and patent litera-
`ture, the current state of knowledge around these
`properties is distilled. Each chapter begins with
`why the property under discussion is important,
`how to measure it and typical values. This is followed
`by a discussion of the science behind how materials
`influence these properties. Subjects include heat seal-
`ing, barrier, physical strength, abuse resistance, adhe-
`sion,
`optical
`properties,
`frictional
`properties,
`shrinkage, and thermoforming.
`Properties of packaging films cannot be thought of
`in isolation of the process used to make them. Part 5
`explores the effect processing has on film properties
`in tandem with material properties. Three chapters
`comprise Part 5, the first of which explores the effect
`of the process on film quality. Flow instabilities and
`other topics that affect material selection are covered.
`The second chapter provides examples of how the
`process directly affects film properties through changes
`in quench rate and orientation. The final chapter looks
`at the effect of processing on interlayer adhesion.
`How the flexible film is ultimately useddthe envi-
`ronment it is subjected to, types of products being
`packageddcan influence film properties and design.
`Part 6 discusses the effect of the end-use environment
`(temperature, humidity, pressure, and irradiation),
`packagingeproduct interactions, and aging on package
`performance. The cost of the package is a predominant
`factor in any package design. Here both financial costs
`(film raw material and converting costs, packing line
`productivity, and waste due to package failure) and
`environmental costs are considered.
`
`The final section brings together the ideas intro-
`duced in earlier parts into a concluding section on
`structure design. Principles of design, analytical
`methods to determine what structures are currently
`in use and modeling approaches are covered.
`There are also two important appendices. The first
`is a system for writing multilayer structures, authored
`by my longtime colleague at DuPont, Scott Marks.
`His system provides a coherent method for communi-
`cating package design throughout the industry which
`is used in this book. The second provides some
`typical packaging structures that have been in use
`for various applications over the years. The intention
`is only to provide some examples and not an exhaus-
`tive, or even current, list of structures.
`Taking on a project like this is a huge endeavor. I
`have many people to thank, too many to name indi-
`vidually. I want to acknowledge my friends and
`colleagues at DuPont who have taught me so much
`over the years about flexible packaging and where
`most of my knowledge has come from. My longtime
`association with the Society of Plastics Engineers
`and TAPPI has also enriched my understanding of
`polymer processing and film properties.
`Finally I would like to thank my family, Kathy,
`Elizabeth, and Sara, for their encouragement and
`for putting up with my long hours of writing and
`editing.
`
`Barry A. Morris
`August 10, 2016
`
`0004
`
`

`

`1 Introduction
`
`The primary function of a package is to protect
`the product, and it is through this function society
`derives the most benefit by preventing food waste,
`enabling economies of scale in the production and
`distribution of goods, and aiding in the access of
`health care to all parts of the world. Packaging has
`evolved to meet the changing needs of the value
`chain; for example, packaging in modern times
`increasingly serves as a communication platform,
`providing content
`information,
`instruction, and a
`marketing message. Flexible packaging is ideally
`suited to meet the challenges of the marketplace and
`is the fastest growing form of packaging. Multilayer
`film technology drives this growth by allowing
`specialized layers with sealing, barrier, or abuse
`resistance properties to be combined to meet the
`packaging requirements in the most cost-effective
`manner. Adding
`to
`this
`is
`the
`variety
`of
`manufacturing processes
`that can be used to
`assemble these structures. Future trends will drive
`further specialization, which underscores the need
`for fundamental understanding of flexible pack-
`aging technology.
`
`1.1 History of Packaging
`
`Early hunter-gatherer societies likely used animal
`skins and other textiles to transport and store food.
`The development of agriculture at least 10,000 years
`ago coincided with the advancement of other forms
`of packaging. Farming fostered the growth of larger
`societies and the need to store food. Early granaries
`probably used baskets woven from various plants.
`The earliest evidence for basket weaving dates back
`about 10,000e12,000 years ago, but earlier artifacts
`may not have survived [1] (Fig. 1.1).
`Basket weaving is the direct predecessor of pot-
`tery since baskets were used as the mold for ceramic
`vessels before the invention of the pottery wheel.
`The earliest known functional pottery vessels for
`storing water and food date back to about 10,000 BC
`[2]. The Egyptians, Greeks, and later Romans used
`pottery vessels called amorpha to transport a variety
`of food and other products. These two-handled clay
`pots are about half the size of today’s 55-gallon
`(208 L) drum. They have been found on many ship
`wrecks from these times, indicating that they played
`
`Packaging Timeline
`Basket weaving
`Early glass making
`Early poƩery
`
`IndustrializaƟon
`of glass in Egypt
`
`Glass
`blowpipe
`
`Paper packaging in
`China
`
`10,000 BC
`
`7,000 BC
`
`1500 BC
`
`300 BC
`
`100-200 BC
`
`Paper
`from
`wood
`pulp
`Aluminum
`Paper
`foil
`bag
`
`Cardboard
`box
`Canning
`process
`
`PP
`
`Blown film
`Oriented
`PET film
`EVA
`
`Extrusion
`coaƟng
`
`LDPE
`
`Oriented
`PP film
`Coextrusion
`Ionomers
`LLDPE
`
`PET
`boƩle
`Zippers
`EVOH MAP
`mPE
`
`Nanocomposites
`PLA
`
`PHA
`
`1809
`
`1817
`
`1844
`
`1867
`
`1910
`
`1930’s
`
`1940’s
`
`1950’s
`
`1960’s
`
`1970’s
`
`1980’s
`
`1990’s
`
`2000’s
`
`Figure 1.1 Milestones in packaging history.
`
`The Science and Technology of Flexible Packaging. http://dx.doi.org/10.1016/B978-0-323-24273-8.00001-0
`Copyright © 2017 Elsevier Inc. All rights reserved.
`
`3
`
`0005
`
`

`

`4
`
`THE SCIENCE AND TECHNOLOGY OF FLEXIBLE PACKAGING
`
`an important part in early civilization commerce [3]
`(Fig. 1.2).
`An offshoot of pottery is glass, which dates back to
`around 7000 BC and was industrialized in Egypt in
`1500 BC. The blowpipe was invented by the Phoe-
`nicians in the 3rd century BC. The modern era of
`glass packaging dates back to 1889 when the auto-
`mated bottle making machine was developed [4].
`Rigid packaging got its jumpstart from Napoleon,
`who in the late 1700s offered an award for improved
`packaging to feed his army. In 1809, Nicholas Appert
`of France invented a way to preserve food through
`sterilization and the canning process was born. One
`year later Peter Durand of England received a patent
`on various forms of packaging and is generally
`credited with the invention of the tin can [5,6]. Tin
`was later replaced by steel and aluminum.
`Tin foil was marketed for food packaging in the
`late 1800s but left an off-taste. Aluminum foil was
`first produced in France and Switzerland in the early
`1900s and in the United States by 1913. Neher
`patented a continuous rolling process in 1910;
`packaging was an early application. By 1921 the first
`foil-laminated paperboard carton was introduced.
`The first heat sealing foil was developed in 1938.
`During World War II, aluminum foil found use as a
`
`Figure 1.2 Amorpha in Turkey. Photo by Tim
`Rogers.
`Reproduced with permission under terms of the GNU Free
`Documentation License.
`
`packaging medium, which helped establish it as a
`mainstream flexible packaging substrate [7].
`Next to animal skins, paper may be the oldest form
`of flexible packaging [8]. The Chinese used an early
`form of paper to wrap foods in 100e200 BC. The
`technology evolved and was transported to the Mid-
`dle East, Europe, and England over
`the next
`1500 years. Early paper was made from bark, flax
`fibers, or old linen rags. Wood pulp was first used to
`make paper in 1867. Two other developments in the
`1800’s contributed to paper’s growing use as a
`packaging medium: the paper making machine and
`flexographic printing [9]. These developments spur-
`red the commercialization of various packaging
`forms, such as the paper bag (1844), the cardboard
`box (1817), corrugated paper (1850), and the paper
`carton (1870) [8].
`Paper-based packaging continued to grow well
`into the mid-1900s, when plastic substrates became
`widely available. The introduction of cellophane
`marks the beginning of the modern era of flexible
`packaging. Invented in 1908 by Jacque E. Bran-
`denberger, a Swiss textile engineer, it initially only
`found limited use for wrapping candy and choco-
`late. This clear flexible film had one major draw-
`back: it had very poor moisture vapor barrier, many
`times worse than wax-coated paper available by
`this time. The DuPont company acquired the US
`patent rights to manufacture cellophane and hired a
`young scientist in the mid-1920s named William H.
`Charch to improve the technology. By 1927 Charch
`had come up with a solution: a thin, transparent
`coating that made the film water tight [10]. This
`coincided with major changes in the lifestyles of
`American consumers. Before then, most food was
`purchased in open markets or small stores. The
`modern supermarket was beginning to come onto
`the scene, emphasizing self-service over custom-
`ization. The availability of a crystal clear film
`transformed the market, allowing the store to pre-
`package goods in a way that the consumer could
`see what was being packaged. DuPont heavily
`advertised their miracle film to consumers for its
`clarity, protection, and convenience: it allowed the
`shopper to save time by not having to wait for a
`clerk to serve them [10,11]. Two of these adver-
`tisements are reproduced in Figs. 1.3 and 1.4.
`By the 1960’s much of the cellophane had been
`replaced by polyvinyl chloride, biaxial-oriented
`polyester (developed in the mid-1950s at DuPont,
`ICI, and Hoechst) [14] or oriented polypropylene
`
`0006
`
`

`

`1: INTRODUCTION
`
`5
`
`Figure 1.3 1948 Cellophane advertisement.
`Courtesy of E. I. du Pont de Nemours and Company and Hagley Museum and Library [12].
`
`(ICI, 1961) [15]. Metallized film, formed by physical
`or vacuum vapor deposition of a thin layer of
`aluminum, was first commercialized in the 1930s for
`Christmas tinsel. It was adapted for packaging films
`and paper in the 1970s [16].
`Polyethylene (PE) is the largest volume plastic
`used in flexible packaging today, valued for its water
`barrier,
`toughness, sealability, and transparency.
`Hans von Pechmann first made PE, although he did it
`accidently when heating diazomethane in a test tube
`
`in 1898. The white waxy substance was analyzed by
`colleagues to contain long molecules which they
`dubbed polymethylene. In the 1930s, ICI developed
`the high-pressure free radical polymerization process
`for making low density polyethylene (LDPE).
`Commercialized in 1939, LDPE was used during
`World War II for radar and cable insulation. DuPont
`collaborated with ICI and US production began in
`1943. Union Carbide and Dow Chemical were also
`producing LDPE by the 1950s [17].
`
`0007
`
`

`

`6
`
`THE SCIENCE AND TECHNOLOGY OF FLEXIBLE PACKAGING
`
`Figure 1.4 1949 Cellophane advertisement.
`Courtesy of E. I. du Pont de Nemours and Company and Hagley Museum and Library [13].
`
`Linear low density polyethylene (LLDPE) and
`high density polyethylene (HDPE) were developed in
`the 1950s. The technology involves using a catalyst
`and coordination chemistry. There are three basic
`chemistries: chromium typically used in slurry and
`gas phase processes, ZieglereNatta in gas and solu-
`tion processes, and metallocene in all processes. The
`chromium catalyst process was developed at Phillips
`Petroleum in the 1950s and introduced as Marlex
`HDPE. Karl Ziegler (Germany) and Giulio Natta
`
`(Italy) conducted their research in the 1950s and
`LLDPE was commercialized in the 1970s. Metal-
`locene PE was discovered by Walter Kaminsky and
`Hansjorg Sinn in Germany in 1976 and developed by
`Dow and ExxonMobil in the 1980s [17].
`Throughout the time period between 1950 and
`1990 other materials used in packaging were intro-
`duced,
`including ethylene vinyl acetate (EVA),
`ethylene acid copolymers, ionomers, polypropylene
`(PP), polyamide 6 (PA6), ethylene vinyl alcohol
`
`0008
`
`

`

`1: INTRODUCTION
`
`7
`
`(EVOH), polyvinylidene chloride (PVDC), poly-
`styrene, and tie resins.
`As the plastics materials advanced, so did the
`processes to convert them into flexible packaging.
`Extrusion coating is a case in point. Following World
`War II, in 1946 and 1947, H P. Smith developed an
`early process for coating LDPE onto paper. The
`process of today involving coating a free film onto
`paper was developed during the same time period by
`DuPont, working with Hartig Engine and Machine
`Co. DuPont worked closely with St. Regis Co., which
`was the first to make extrusion-coated products on a
`commercial scale. International Paper, Sealright and
`Egan were also early innovators. By 1957, the first
`LDPE-coated milk carton was commercialized. From
`there, the technology advanced to many other pack-
`aging forms [18].
`The blown film process also developed with the
`advent of LDPE. The demand for waterproof pack-
`aging films with good low-temperature toughness
`progressed in the 1940s and 1950s, and LDPE was
`just the plastic to fit this need. The technology to
`make blown film advanced through this time period,
`mostly by film producers that made their own dies
`and ancillary equipment. Visking Company is re-
`ported to be the first company to develop PE extru-
`sion. Most of
`the technology remained closely
`guarded company secrets until the late 1950s when
`resin suppliers began buying up film producers and
`opening up the technology to grow the market for
`their resins [19].
`Extrusion processes were first used in the mid-
`1800s to make sheet of gutta-percha, rubber, and
`shellac. Modern looking screw extruders appeared in
`the mid-1930s in Germany and the United States
`[20]. As materials were developed, so were the sheet
`and other flat die processes like cast film and extru-
`sion coating.
`into multilayer flexible
`Combining materials
`packaging has been practiced since the beginning of
`the modern packaging era. Coatings onto paper, such
`as wax or clay, were used early on to provide
`moisture resistance. By the 1940s adhesives were
`being used to bond sealant layers onto substrates like
`cellophane and aluminum foil. Coextrusion, where
`the layers are combined during the film fabrication
`process, was commercialized for flat die extrusion
`in the 1960s, followed shortly thereafter for blown
`film [21,22].
`Packaging machinery also evolved with the
`availability of new materials from early bag making
`
`machines to form-fill-seal machinery. The vertical-
`form-fill-seal machine was patented by Walter
`Zwoyer in 1936 [23].
`Packaging forms have advanced throughout the
`years with ever more sophistication. Paper bags
`were introduced in the 1840s with glued paper
`sacks with gussets in the 1870s. Laminated paper
`cartons with aluminum foil were introduced in
`1921. Wax-coated milk cartons appeared in the
`early 1900s [24] and the LDPE-coated version in
`1957. Modified atmosphere barrier packaging for
`improving the shelf life of meat products came into
`use in the 1970s. Zippers were used in the 1950s
`but not extensively into flexible packaging until the
`1980s. The stand-up pouch gained popularity in the
`1990s.
`the dynamic growth of
`throughout
`A constant
`multilayer flexible packaging over the past 50 years
`has been the continued advancement of technology,
`whether it is resin, substrate, process, or package
`form. Today there is a plethora of packaging materials
`and forms that are continuing to evolve as packaging
`needs change. While one or two layers may have been
`common a few years ago, now five, seven, and nine
`layers are the norm with some package structures
`utilizing hundreds of layers. Often there are multiple
`ways to solve a package need either by changing
`layers or the process. For example, a barrier film can
`be made by laminating a barrier substrate like
`aluminum foil to a heat seal film or by coextruding a
`barrier resin like ethylene vinyl alcohol copolymer
`(EVOH) with a sealant. Often the choice depends on
`the secondary needs of the application as well as what
`equipment the converter has.
`
`1.2 Benefits of Packaging
`
`The function of packaging is to aid in the distri-
`bution of goods for the benefit of society [25]. From
`an engineering perspective, the package protects the
`product. For a food product, this typically means it
`prevents spoilage or extends the shelf life of the
`product before the consumer uses it. Barrier and
`abuse resistance are two primary considerations.
`Barrier may involve the creation of hermetic seals,
`blocking light, or providing low permeation to gases
`such as moisture and oxygen. It also may include
`preventing food component migration into the
`package or package component migration into the
`food. The package may aid in the prevention of
`
`0009
`
`

`

`8
`
`THE SCIENCE AND TECHNOLOGY OF FLEXIBLE PACKAGING
`
`harmful microbe growth by allowing for post pack-
`aging sterilization through techniques such as retort,
`radiation, or high-pressure pasteurization.
`Packaging abuse comes in many forms. The
`package may be subjected to slow puncture, as from a
`sharp product within the package such as a bone or
`noodle. High-speed impact events may occur during
`filling, handling, and distribution. Cold or hot storage
`may be a factor. The package may be subjected to
`internal pressure created by elevation changes during
`transport. The ability to withstand such abuse must be
`designed into the package.
`From a marketing perspective the package is an
`advertisement. Often it is the only mechanism the
`brand owner has to inform and entice the consumer.
`Sparkling graphics can aid in grabbing the attention
`of the consumer and informing the customer why he
`or she should purchase the product. To this end, the
`package often must provide a surface for printing.
`The entire or parts of the package may need to be
`transparent so the consumer can see what he or she is
`purchasing.
`From an operations perspective, an ideal package
`has an efficient form factor, allowing for ease of
`transportation. The shape of the package impacts
`how many packs can fit on a pallet and on a truck. It
`also influences what can be put on a shelfddoes it
`stand up on its own or does it need a peg? Can it be
`stacked one high on the shelf or more than one high?
`Such forms influence where the product may be
`displayed in the store.
`From a legal perspective, the package performs a
`service by providing a medium for displaying con-
`tent. Label laws in many countries require ever more
`space on the package to the extent that many phar-
`maceuticals have labels that open out to display all
`the requisite information. Labeling laws may require
`a list of ingredients, net weight, dosage, and various
`disclaimers. The brand owner may also want
`to
`include contact information, recipe suggestions, and
`so on.
`The benefits of packaging to society are numerous.
`Packaging helps reduce world hunger, spurs eco-
`nomic development, enables life-saving measures in
`health care, and contributes to sustainability. The UN
`estimates that the world population will reach 9
`billion people by 2043 [26], 2 billion more than in
`2012. Increasing food production as well as reducing
`waste will be essential for feeding the world. The
`United Nations Food and Agriculture Organization
`estimates that about 1/3 or 1.3 billion tons of food are
`
`wasted each year [27]. An Institute of Mechanical
`Engineers study [28] concludes from 30% to 50% of
`food is wasted. The cause of food waste differs by
`country. Poor distribution and infrastructure results in
`substantial food loss in developing countries. Pack-
`aging can play a key role in preserving food
`throughout the food chain, as has been demonstrated
`in the developed world. Transferring best practices to
`the developing world will go a long way to help
`reduce the potential for future food shortages.
`In developed countries, more food makes it to the
`consumer, where more is wasted. Part of this is due to
`excessive buying by the consumer. Packaging can
`also play a role here. While single-use packaging
`appears wasteful, portion control packaging can
`actually be more sustainable than bulk packaging if it
`cuts down on the amount of unused food. Advances
`in barrier and reclosable technologies may also
`extend shelf life at the consumer level, helping to cut
`food waste.
`Packaging in recent years has often been demon-
`ized as part of the sustainability problem. But if the
`whole food chain is considered, packaging turns out
`to be only a small contributor to environmental stress.
`Bu¨sser et al. [25] evaluates the impact of packaging
`on several food products. They find that the impact
`from packaging is minor compared with the product.
`For example, for coffee, cultivation and brewing
`make up 82e99% of the nonrenewable energy con-
`sumption and greenhouse gas emissions. Packaging
`only contributes about 1e5% depending on product
`package type. The study also considers ozone layer
`depletion, acidification, and eutrophication. These
`impacts are also not significantly impacted by the
`package. Similar conclusions are made for the two
`other food products considered: frozen spinach and
`butter. For frozen spinach, keeping the product cold
`throughout distribution, and in particular at the con-
`sumer, is found to be responsible for most of the
`environmental stress. Butter production overwhelms
`other factors, including packaging, for environmental
`impact. Indeed, one can conclude that the package
`prevents the environmental stress from being even
`greater due to prevention of spoilage and damage
`throughout distribution and use.
`Although packaging can reduce the environ-
`mental impact of the food distribution process, there
`are still opportunities to reduce environmental stress
`through material
`choice, optimizing package-
`converting processes and reduction of packaging.
`Indeed, the recent trend toward reducing packaging
`
`0010
`
`

`

`1: INTRODUCTION
`
`9
`
`by switching from rigid packaging, such as steel
`cans or glass jars, to flexible packaging is driven in
`part by this dynamic (the other driver is economic
`cost). There have been a number of studies trying to
`compare one package type versus another. Some are
`of dubious standing, sponsored by special interest
`groups from one side or another. But intuitively,
`reducing the amount of material usage should
`reduce environmental impact. A study by the Flex-
`ible Packaging Association [29] shows substantial
`reduction in nonrenewable energy consumption and
`greenhouse gas emissions when switching from
`rigid or even paper packaging to plastic flexible
`packaging. For example, switching from glass or
`metal beverage containers to a plastic stand-up
`pouch reduces energy consumption by 50% and
`greenhouse gas emissions by 75%. No doubt this
`study is motivated by enhancing the status of its
`members, but nevertheless, reducing the amount of
`material used in a package makes inherent sense
`both from a financial and environmental cost
`perspective.
`Packaging also provides numerous benefits to the
`health and well-being of society [30]. Medical de-
`vices packaged in easy-open, tamperproof, and ster-
`ilizable packaging ensure that instruments are safe
`for use in the operating room. Packaging enables
`pharmaceuticals to reach remote areas of the world
`where cold storage or sanitary conditions does not
`exist. Emergency relief operations depend heavily
`on prepackaged goods for fast delivery to areas
`in need.
`It is no coincidence that the use of packaging has
`expanded in the era of mass production and
`merchandising [31]. Huge supply chains have
`developed involving unfinished parts or goods being
`transported from place to place. This would not be
`possible without packaging. Packaging has helped
`spur economic development by enabling self-service
`purchasing by consumers. It has cut the cost of
`distributing, promoting, and ensuring the quality of
`products, and servicing consumers. Packaging has
`replaced the sales clerk in many markets by
`providing information on the label. By taking cost
`out of the supply chain, the cost of goods sold has
`decreased, making products more affordable to the
`mass market.
`Packaging does have some negative impact on
`society and the environment, especially when not
`used responsibly. These include greenhouse gas
`emissions during production, possible release of
`
`toxins into the environment, the scarring of land-
`scapes from mining pits (aluminum) or clear cutting
`(paper), and the accumulation of plastics in our
`oceans [32]. Clearly, more can be done to reduce
`these negative consequences, such as more recy-
`cling and better collection of used packaging. But
`the benefits of packaging, especially flexible pack-
`aging, are numerous and generally outweigh the
`negatives.
`
`1.3 Consumption Patterns
`
`Flexible packaging has grown faster than other
`packaging forms over the last several decades. The
`primary driver has been cost. Flexible packaging
`generally uses less material on a weight basis than
`other packaging forms, resulting in less material us-
`age as well as savings in transportation. Rigid
`packaging historically held the advantage in terms of
`reclosability (caps and lids) and high temperature
`sterilization, but flexible packaging has closed the
`gap as new technologies have been introduced.
`The size of the flexible packaging market depends
`on how it is defined. The Flexible Packaging Asso-
`ciation as well as PCI Films Consulting define it as
`follows, which is adopted here:
`
`Flexible packaging, as PCI Films Consulting
`defines it, embraces the manufacture, supply
`and conversion of plastic and cellulose films,
`aluminum foils and papers that are used
`separately or in combination,
`for primary
`retail
`food packaging; non-food packaging
`applications
`such as pet
`food, DIY [do
`it
`yourself],
`hygiene-product
`overwrap,
`household detergents,
`tobacco; and certain
`other specialist non-food packaging sectors,
`such
`as medical
`and
`pharmaceutical
`packaging. PCI’s definition relates specifically
`to value-added, converter-supplied flexible
`packaging (printed, laminated, coextruded or
`made into bags and pouches). The value of
`flexible packaging is measured at the packer
`level. This definition specifically excludes
`shrink and stretch films used for secon