Adhesives and Their Use in Microwave Packaging

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Adhesives and Their Use in Microwave Packaging

• Li Xiong
• School of Packaging
• Michigan State University

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Overview of Presentation

• Instructions
• Delete sample document icon and replace with
  working document icons as follows
• Create document in Word.
• Return to PowerPoint.
• From Insert Menu, select Object
• Click Create from File
• Locate File name in File box
• Make sure Display as Icon is checked.
• Click OK
• Select icon
• From Slide Show Menu, Select Action Settings.
• Click Object Action and select Edit
• Click OK

• Adhesives
• What Is It?
• How does it work?
• What We Have?
• Microwave Packaging
• What is microwave?
• Conventional Heating vs. Microwave Heating
• Microwave and Packaging
• Microwave Packaging Materials

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Overview of Presentation (cont.)

• Microwave Packaging (cont.)
• Microwave Packaging Forms
• Active and Passive Microwave Packaging
• Primary and Secondary Packaging
• Popcorn Bags Evolution
• Adhesives Used in Microwave Packaging
• Effect of Adhesives on the Food Taste/Flavor
• Future of Microwave Packaging

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Adhesives--What is it?

• Instructions
• Delete sample document icon and replace with
  working document icons as follows
• Create document in Word.
• Return to PowerPoint.
• From Insert Menu, select Object
• Click Create from File
• Locate File name in File box
• Make sure Display as Icon is checked.
• Click OK
• Select icon
• From Slide Show Menu, Select Action Settings.
• Click Object Action and select Edit
• Click OK

• Adhesive is defined as any material that is
  capable of bonding and holding two surfaces.
• --The Adhesion Committee of IoPP

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Adhesives--What is it? (cont.)

• Instructions
• Delete sample document icon and replace with
  working document icons as follows
• Create document in Word.
• Return to PowerPoint.
• From Insert Menu, select Object
• Click Create from File
• Locate File name in File box
• Make sure Display as Icon is checked.
• Click OK
• Select icon
• From Slide Show Menu, Select Action Settings.
• Click Object Action and select Edit
• Click OK

• Liquid, solid or pressure sensitive
• Forms a joint or bonds two substrate together
• Specific formula, specific manufacturing process
  for specific use

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Adhesives -- How does it work?

• Instructions
• Delete sample document icon and replace with
  working document icons as follows
• Create document in Word.
• Return to PowerPoint.
• From Insert Menu, select Object
• Click Create from File
• Locate File name in File box
• Make sure Display as Icon is checked.
• Click OK
• Select icon
• From Slide Show Menu, Select Action Settings.
• Click Object Action and select Edit
• Click OK

• Adhesive and cohesive bond
• Adhesive bond is the bond between adhesive and
  the adherend.
• Cohesive bond is the force of intermolecular
  attraction within the adhesive or adherend.
• Factors influencing adhesive/cohesive bond
  strength
• Adhesive surface tension, solubility, and
  viscosity
• Cohesive molecular and physical structure of the
  material

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Adhesives -- How does it work? (cont.)

• Instructions
• Delete sample document icon and replace with
  working document icons as follows
• Create document in Word.
• Return to PowerPoint.
• From Insert Menu, select Object
• Click Create from File
• Locate File name in File box
• Make sure Display as Icon is checked.
• Click OK
• Select icon
• From Slide Show Menu, Select Action Settings.
• Click Object Action and select Edit
• Click OK

• Three mechanisms
• mechanical physical or interlocking interface
  between the materials
• specific molecular forces create bonding of two
  nonporous materials
• pressure-sensitive two-stage bonding process

8
Adhesives -- What we have?

• Instructions
• Delete sample document icon and replace with
  working document icons as follows
• Create document in Word.
• Return to PowerPoint.
• From Insert Menu, select Object
• Click Create from File
• Locate File name in File box
• Make sure Display as Icon is checked.
• Click OK
• Select icon
• From Slide Show Menu, Select Action Settings.
• Click Object Action and select Edit
• Click OK

• Adhesives could be classified in three ways
• Natural or synthetic
• Mechanism of bond formation
• Method of bonding

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Adhesives -- Natural or Synthetic

• Instructions
• Delete sample document icon and replace with
  working document icons as follows
• Create document in Word.
• Return to PowerPoint.
• From Insert Menu, select Object
• Click Create from File
• Locate File name in File box
• Make sure Display as Icon is checked.
• Click OK
• Select icon
• From Slide Show Menu, Select Action Settings.
• Click Object Action and select Edit
• Click OK

• Natural animal glue, casein, starch, dextrin,
  and natural rubber
• Pros natural, biodegradable
• Cons prone to attack by microorganisms, shorter
  shelf life
• Synthetic
• Pros good bonding strength, multiple choices
  available
• Cons most are not biodegradable nor recyclable

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Adhesives -- Mechanism of bond formation

• Loss of carrier (water or solvent)
• Loss of heat
• Chemical reaction

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Adhesives -- Method of bonding

• Instructions
• Delete sample document icon and replace with
  working document icons as follows
• Create document in Word.
• Return to PowerPoint.
• From Insert Menu, select Object
• Click Create from File
• Locate File name in File box
• Make sure Display as Icon is checked.
• Click OK
• Select icon
• From Slide Show Menu, Select Action Settings.
• Click Object Action and select Edit
• Click OK

• Single stage
• Wet bonding Hot melt
• Two stage
• Heat seal
• Pressure-sensitive

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Microwave Packaging

• What is Microwave?
• Conventional vs. Microwave Heating
• Microwave and Packaging
• Active and Passive Microwave Packaging
• Primary and Secondary packaging

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What is Microwave?

• Microwaves are a form of electromagnetic energy
  and are generally thought of as occupying the
  frequency spectrum from 0.3 to 300 GHz, or
  wavelengths of 1 mm to 1m.
• Stanley Sacharow, Microwave Packaging

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Conventional vs. Microwave Heating

• Conventional heating
• heating from surface to interior
• time consuming (thermal lags)
• could reach browning and crispness
• tends to heat evenly

• Microwave heating
• heating inside and outside at the same time
• very fast
• browned and crisped foods not easily obtained
• tends to heat unevenly

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Some Facts of Microwave

• By 1991, about 85 of US households own at least
  one microwave oven
• 100 million microwave ovens out of 150 millions
  worldwide are owned by Americans
• US microwave market valued approximately US2,000
  million in the early 1990s
• In Europe, Germany takes the lead, followed by
  France and the UK
• In Asia, the leading microwave oven owners are
  Japanese and Australian.

Click for microwave history
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Microwave and Packaging

• Packaging holds the key to the future use of
  microwave heating.
• -- Anon, Microwave packaging
• The increased usage of microwave ovens
  highlighted the importance of the relationship
  between a food and the right packaging
• -- Stanley Sacharow, Microwave packaging

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Microwaveable Foods in US

• Popcorn is the No.1 in US, with sales of about
  US600 million in 1989. Others sold in US
  include pizza, vegetable and desserts
• Total sale of microweveable foods in US amount to
  US3 billion in 1992 compared to US1 billion in
  1987

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Microwave Packaging Materials

• Paperboard
• Glass
• Plastics
• Metals

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Microwave Packaging Forms

• Click for Microwave Packaging Forms

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Active and Passive Packaging

• Active packaging -- that constructed of material
  (susceptor) which is capable of focusing incident
  energy and converting into heat in a
  predetermined region of food.
• Passive packaging -- that does not modify the
  microwave energy field.

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Primary and Secondary Packaging

• Primary packaging -- packaging system in direct,
  or potentially direct, contact with food.
• Secondary packaging -- those make no direct
  contact with food, but may become a source of
  odors when heated in the microwave oven.

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Popcorn Bag Evolution (US)

• Click for popcorn bag evolution

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Adhesives in Microwave packaging

• Primary packaging
• sealing lidding stock
• paperboard/seal material/flange
• sealing pouches and bags
• bonding susceptors
• Secondary packaging
• folding cartons for containing primary food
  packages
• coextrusion (tie layer) and coinjection adhesives

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Adhesives and Microwave packaged Food

• Food safety
• must comply with government regulations.
• Food taste and flavor
• might be the results of degradation of adhesives
  being used to construct the package
• its still a blank area to be investigated

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Potential Approaches

• Good choice of monomers, colloidal stabilizers,
  polymerization conditions and post-polymerization
• implies only to those whose principal component
  is one or more emulsion polymers
• to eliminate low molecular weight materials
• Choose right adhesive formula
• Control drying process in lamination

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Future of Microwave Packaging

• Some trends include
• increased shelf-stable and refrigerated markets
• new susceptor technologies
• increased environmental concerns
• health consciousness
• safety concern

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Thanks and Any Questions?