Developments in Nanotechnology for Flexible Packaging

76 Pages·1.449 MB·English

by  Pira International Ltd

Developments in Nanotechnology for
Flexible Packaging
Edward Petrie
Published by
Pira International Ltd
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ISBN 1 85802 556 7
© Copyright
Pira International Ltd 2006
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Contents
List of tables iv Clay modification 28
List of figures v Carbon nanoparticles 29
Executive summary vii Nano-oxides 32
1
Polyhedral oligomeric silsesquioxane
(POSS) 33
Polymeric resins 34
Nanocomposite manufacturing
Introduction 1 methods 36
Nanotechnology and flexible packaging Incorporation of nanofillers into the
– a marriage of convenience? 1 resin 37
Nanomaterials’ position among other Conversion of nanocomposite into
a film 41
packaging solutions 2
4
Objective, scope and methodology 4
2
Nanotech state of the art in flexible
packaging 43
How nanomaterials enhance flexible
Polyamide (nylon) nanocomposites 44
packaging 7
Polyolefin nanocomposites 47
Advantages of downsizing – an
Other polymeric composites 48
introduction to nanomaterials 7
Nanocoatings 49
Key features of nanomaterials in flexible
Inks, pigments 49
packaging 10
Nanofilms 50
Barrier properties 12
5
Bulk mechanical properties 13
Flame resistance 15
Biodegradability 16
Safety and security 18
Current and future market trends 53
Responsive films 18
The overall flexible film and packaging
Product identification 19
market 53
Colour, clarity 20
Nanomaterials 54
UV stability 21
Nanomaterials in packaging 54
Chemical and moisture resistance 21
Future vision 56
Electrical and thermal conductivity 22
Drivers for nanotechnology 57
3
Barriers to nanotechnology 58
6
Components and manufacture of a
nanocomposite material 23 Stakeholders 61
Nanofillers 24
Nanoclays 24 Bibliography 65
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List of tables
1.1 Summary of suppliers and the barrier 3.2 Different polymers and the
technologies they are developing or various processes used to make
have introduced to the market 3 nanocomposites 37
1.2 Nanomaterials used in flexible 3.3 Effect of 6% nanoclay on properties
packaging 4 of a polypropylene homopolymer 39
2.1 Properties of nanocomposite nylon 3.4 Polypropylene nanocomposites made
moulding compound compared with by the slurry process compared with
conventional reinforcement 8 classically compounded materials 41
2.2 Characteristic length scales in solid 4.1 Partial listing of organoclay
state science 10 nanocomposite suppliers to the
2.3 Nanocomposite consumer packaging flexible packaging industry 43
applications versus property 4.2 Honeywell nylon 6-clay
improvements 11 nanocomposite compounds 44
3.1 Nanomaterials – big promises in
small packages 24
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List of figures
2.1 The price of nanomaterials drives 3.2 Polymeric nanocomposites are a
their use 9 class of reinforced polymer with low
2.2 Tortuous path created by platelets quantities (less than 5%) of platelet
within a polymer matrix contributes sized nanometric clay particles 25
to the high barrier properties of 3.3 Types of polymer layered
nanocomposites 13 nanocomposites 26
2.3 Enhanced thermal stability measured 3.4 Clay modification to provide
via thermogravimetric analysis (TGA) exfoliation 27
for a thermoplastic resin (HDPE) with 3.5 Multiwall carbon nanotubes 31
nanoclay addition 14 4.1 Oxygen barrier versus relative
2.4 Cone calorimetry data for humidity; non-oriented films at
polystyrene (PS) and a PS 23°C 45
nanocomposite 16 4.2 CO retention of multilayer bottles 46
2
3.1 Top-down and bottom-up approaches 5.1 Global consumption of
to producing nanomaterials 23 nanocomposites, 2005–11 55
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Executive summary
Nanotechnology is a cross-sectional technology, and it will play an important future
role in almost all areas of technical endeavour. Nanotechnology has become the focus
of immense expectations in terms of market potential and efficiency. Although there
has been a plethora of start-up companies, research funding, and even several highly
publicised commercial successes, the early market expectations have not been realised,
and many people are wondering: how big is the gap between fantasy and reality?
One of the problems with nanotechnology is that it is being used to describe all
new things where smaller is seen as better. This includes materials, devices and systems.
However, in certain areas the advent of nanomaterials is changing how we fundamentally
think about structures and their properties, and the hype may be legitimate.
This report attempts to characterise the current state of nanotechnology in the
flexible packaging industry. Packaging is a relatively large and important application for
nanotechnology. Materials constructed from nanotechnology have been found to provide
unexpected and valuable packaging properties. These properties may even be of such
high value that they can justify the early price of nanomaterials.
The most commercially interesting nanotechnology-based products developed for
flexible packaging are polymer nanocomposites. These are polymeric compounds that
consist of discrete fillers in the order of a few nanometres and with immense surface
areas. These compounds can be processed into film and other packaging materials using
conventional conversion equipment. Nanocomposites represent a radical alternative
to traditional filled polymers and polymer blends. The enhanced properties that these
materials can provide are both considerable and surprising. The surprise comes from the
fact that by being so small the nanofillers are in the same size range as the polymer
molecules and react directly with them. As a result, the material properties are affected by
the laws of atomic physics, rather than behaving as traditional bulk materials.
When compared to other nanomaterials, nanocomposites are relatively low cost,
and they can be incorporated into many common polymeric resin systems. Low-volume
additions (1–5 weight percent) of highly anisotropic, high aspect ratio nanoparticles,
such as layered silicates, provide mechanical property enhancements with respect to the
virgin polymer that are comparable with those achieved by conventional filler loadings of
15–40%. This results in significant processing advantages and reduced cost potential due
to downgauging of cross-section.
In addition, unique value propositions are possible for these materials that are not
available with traditional materials. These are the result of properties such as reduced
permeability, tailored biodegradability, optical clarity, electrical and thermal conductivity,
and flame retardancy among others. These properties can be 'engineered' to meet the
exact demands of an application.
Another unique feature of nanocomposites is the lack of property trade-offs. For
the first time, there is an opportunity to design materials without compromises that are
typically found in conventionally filled polymer composites.
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Developments in Nanotechnology for Flexible Packaging
Executive summary
By far one of the most intriguing property enhancements provided by clay
nanocomposites, at least to the flexible packaging industry, is its low gas permeability.
As plastics have become more and more common in food packaging applications, many
concerns have arisen about their ability to allow the exchange of gases (oxygen and
carbon dioxide) and vapours (water and aroma components) that can compromise the
quality and safety of packaged food and beverages. Novel high-barrier nanocomposites
could be the solution to this problem.
Nylon nanocomposites are claimed, for example, to have a 100-fold improvement
reduction in oxygen permeation. They also provide a barrier to the passage of CO that
2
is sufficient to provide significantly improved shelf life. As a result, many of the early
nanofiller and nanocomposite developers are focusing on flexible packaging as the
tastiest of the 'low hanging fruit' available to them for early market entry.
Clay-based nanocomposites are being commercialised having polymer matrices of
polyamide (nylon), polyolefins, polyethylene terephthalate (PET), EVOH, and several other
high-barrier polymers. They are being used as single-layer films and as individual layers in
multilayer films. They are also being used as barrier coatings to other polymers.
Other nanomaterials may eventually affect the flexible packaging industry, but
none as significantly or as quickly as clay nanocomposites. Metal oxide nanoparticles
and structured carbon nanoparticles, such as carbon nanotubes and fibres, will find
applications in niche applications such as UV absorbers and electrostatic dissipative
packaging. However, because of their relatively high cost and exclusive value propositions,
they will not have the impact that clay nanocomposites will have.
If material costs can be reduced further, the future barrier film market is likely to be
dominated by nanoclay composites containing nanoscale clay platelets as filler. The cost
is already relatively low compared with other nanomaterials, but is likely to come down
further due to the fact that clay nanomaterials are naturally available and abundant,
and can be processed in large volumes. The small amount required to provide significant
improvements in properties will also be a factor in their early acceptance.
The vision of future packaging is one in which the package will increasingly operate
as a multifunctional structure, adding value and benefits across the entire packaging
supply chain. For nanomaterials to be adopted in packaging they need to be inexpensive
relative to the value provided by the product, produce reliable and reproducible properties,
and be environmentally benign and safe for food contact. One of the benefits of
nanocomposites is that they do provide multi-functionality to packaging. For example, one
material can be used to provide enhanced strength (or weight reduction due to smaller
gauge film), a high barrier to gas and vapour, flame retardancy, and increased thermal
resistance.
Although nanocomposite barrier films are highlighted in this report, there are other
ways that nanotechnology will affect the flexible packaging industry. Nanomaterials can
be used to make intelligent sensors to measure the age of the product contained within
the package. They can be used as coatings to covertly print information on a package in
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Developments in Nanotechnology for Flexible Packaging
Executive summary
the form of invisible barcodes or other displays. Nanomaterials can also be used to sense
when a package is opened or tampered with.
Other potential uses for nanotechnology in flexible packaging include the
applications of nanometre thick films and coatings. These can be used as individual
barriers in multilayer films, or they can be built up from multiple nano-thick films.
This report provides an introduction to state-of-the-art nanotechnology in flexible
packaging. It examines components and methods for manufacturing nanomaterials and
nanocomposite compounds, and their conversion to packaging products. It identifies
processing difficulties that have delayed widespread acceptance of these materials and
suggests solutions to these problems. Commercially available products from nanomaterials
suppliers and plastic compounders are described, and products that are in the late stages
of development are mentioned as an indication of where the future of the packaging
industry may be headed.
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