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Extrusion Coating
Substrates
Kelly R. Frey
Chevron Phillips Chemical Company LP
TAPPI Extrusion Coating CourseAugust 24-26
Charleston, SC
Learning Objectives Identify the components of a typical extrusion
coated or laminated structure.
Understand the properties and requirements of
each component in a structure.
Understand the various types of substrates
available for use in extrusion coating and
laminating.
Learn how to put various substrates together to
build a structure.
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Substrates
The building blocks used to produce a
n s e s ruc ure.
Materials are selected based on
Function & Design Requirements of the package
What will it hold?
How will it be converted, filled and distributed?
How will it need to look?
How will it be used?
How much protection is required? (Moisture, Gas,Chemical, Flavors, Aromas, Light, Dirt and Dust)
How much will product cost?
E/C & Lamination Lines
E/C & Lamination lines are designed to run
Thin films at low tension levels (5-100lbs oftension) e.g. chip bags
Paper, film and foil combinations (20-200lbs oftension) e.g. stand-up pouch
High tension paperboard applications (150-. . .
.these lines combine resins or adhesives withsubstrates to produce ..
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Typical Structure
Outside / (Bulk, Barrier, and/or Tie) /
Inside
Outside Layer (Primary Substrate)
Considerations for the outside layer: Printable
Print may need to be protected
Maybe sealable (e.g. lap seal)
Maybe not sealable (e.g. fin seal)
Low COF for converting
g scra c res s ance or appearance May need to receive a coating (silicone release
liners)
Adhesion to the next layer
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Tie Layers
Considerations for the tie layers:
Composition of layers being tied together
Adhesion method (adhesive, extrusion,
primers)
Amount of bond required
failure)
Bond strength over time (chemical attack,bond change due to materials, etc).
Bulk Layers
Considerations for the bulk layers: Cost
Thickness/Modulus
Adhesion and compatibility with other layers.
How will the bulk layer affect appearance,
machineability, converting, and use of the
.
How will the bulk layer affect appearance,
machineability, converting, and use of the
structure.
Strength properties (tear, puncture, etc)
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Barrier Layers
Considerations for the barrier layer: Type of barrier (Moisture, Gas, Solvent, Aroma, Light,
Microbial)
How much barrier is required?
Is the barrier also providing grease or chemicalresistance/barrier?
Does the barrier need to be clear or can it be opaque?
Abuse resistance (cracking or pinholes).
barrier?
Dont consider only the permeation through the face of thestructure but permeation through the seal of the package,as well.
Inside Layer (Aux. Substrate)
Considerations for the inside layer
Typically the sealant layer
What will it need to seal to? (lap seal, fin seal)
Seal temperature & seal strength.
Seal through contaminants (powders, grease, etc)
Peelable sealant
Low COF for converting
Food Contact (flavor scalping, taste and odor) Appearance
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Putting it all together
These considerations and requirements
will dictate the types of materials used
in the structure with the overall goal to:
Functionality &
er ormance
Extrusion Lamination / Coating Process
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Substrates
Paper
Advantages Disadvantages
Paper
(Less than
7mils in
thickness)
Measured in
lbs/ream
- Low Cost
- Some bulk and deadfold
- Strength (X,Y & Z Direction)
- Opaque
- Natural and Bleached and Clay
Coated
-Easy to obtain adhesion
(mechanical and chemical)
-Easy and forgiving to run and hide
- Poor Barrier & Chemical Resistance
- Non-Sealable
- Properties change depending upon moisture
content
- Rough surface can produce pinholes.
.
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Paperboard
Advanta es Disadvanta es
Paperboard
(greater than
7mils)
Measured by
thickness
points.
- Strength (X,Y & Z Direction)
- Opaque
- Natural and Bleached and Clay
Coated
-Easy to obtain adhesion
(mechanical and chemical)
-Can be easy to run and hide
gauge bands.
-Easy and forgiving to run and hide
- Poor Barrier & Chemical Resistance
- Non-Sealable
- Properties change depending upon moisture
content
- Rough surface can produce pinholes.
gauge bands.
Cellophane
Advanta es Disadvanta es
Cellophane - Excellent Optics
- Good Stiffness
- Good Printability
- Excellent twist retention
- Good Machineability
- Poor Barrier
- Poor Tear Strength
- Non-Sealable
- Can turn color over time.
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OPP
Advanta es Disadvanta es
OPP - Excellent Optics
- Good Stiffness
- Greaseproof
- Heat Sealable Grades
- Opaque (Cavitated OPP)
-Metallized or PVdC OPP Good
Barrier
-Good Machineability
-Flex resistance vs. Cello hane
- Cost
- Tear Strength
- Treatment or primer required for adhesion
- Metallized surface can scratch easily
.
(2700+ on Gelbo)
OPET
Advanta es Disadvanta es
OPET - Excellent Optics
- Excellent Stiffness (> Than OPP)
- Good Strength
- Good Oxygen Barrier
- High Heat Resistance
- Metallized or PVdC PET Good
Moisture and Gas Barrier
-Good Machineability
- Hi h Abrasion Resistance
- Cost
- Poor Tear Strength, once tear is initiated.Harder to initiate tear than OPP.
- Poor Moisture Barrier Compared to OPP.
- Treatment or primer required for adhesion.
Can be harder to adhere to than OPP.
-Metallized surface can scratch easily
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Foil
Advantages Disadvantages
Foil - Ultimate Barrier (if pinhole free)
- Optics for Decorative Structures
- Cost
- Very Weak
- Non-Sealable
- Hard to Print
- Can be hard to get adhesion.
- At gauges of less than 1mil pinholes can bepresent.
Metallized Film
Advantages Disadvantages
Metallized Film
(Cellophane,
OPP, Nylon &
PET)
- Barrier
- Many grades available,
Cellophane, OPP, Nylon, PET, etc)
- Heat sealable grades available.
- Cost
- If scratched then barrier is significantly
reduce.
- Does not offer the stiffness and deadfold offoil.
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Nylon Film
Advantages Disadvantages
Nylon Film - Optics
- Very high toughness, tensile, and
abrasion resistance.
- Good oxygen barrier.
- High heat resistance (withstand
steam steralization 140C and even
hotter with dry heat).
- Good odor barrier.
- Biax improves strength, stiffness,
- Cost
- High water absorption which change
mechanical properties (only temporarily).
- Does not offer the stiffness and deadfold of
foil.
and optics as well as barrier
- Excellent grease resistance.
PE Films
Advantages Disadvantages
PE Films - Cost (Depending Upon Type)
- Good Optics (Depending upon
type)
- Good Sealability
- Moisture Barrier
- Low Temperature Abuse
Resistance
- Good Toughness and Tear
- Orientation in both directions for
- Cost (Depending Upon Type)
- Low Stiffness Compared to OPP and PET
- Poor oxygen barrier.
-Low Temperature Resistance.
- Subject to environmental stress cracking.
blown film.- Good optics for cast film.
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Cast PP Films
Advantages Disadvantages
Cast PP Films - Cost
- High Elongation at Break
- MVTR better than LDPE but not
quite as good as HDPE.
- Chemical Resistance
- Oil & Grease Resistance
- Good Twist Retention
- Poor Tear Strength
- Poor Impact Strength at Low Temp (below
0C)
-Low Temperature Resistance.
- Subject to environmental stress cracking.
Capital Cost
CAST FILM BLOWN FILM
Film Process Comparison
Output
Gauge Control
Optical
Properties
Retrofit to Coex
Film Strength
Biax Orientation
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Non-Wovens
Advantages Disadvantages
Non-Wovens
(PET, PP, &
Cellulose)
- Cloth like appearance and feel
- Breathable
- High Bulk
- High Strength
- Easy to get adhesion (mechanical
adhesion).
- Specialty applications:
-Filters, Wipes, Automotive,
Building Materials, Hygiene, etc.
- Low Barrier
- Low Grease and Chemical Resistance
- Pinholes
MVTR
100
1
10
G-m
il/100sq.i
n./
day/atm
0.1
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1000
OTR
10
100
c-m
il/100sq.i
n./
day/atm
0.1
Barrier Coatings Aluminum and Silicon Oxide Coatings
Al2O3 & SiOx are now being applied to PET and OPP to improve.
Produces metal-free, retortable, microwavable, transparent,environmentally friendly, high barrier films.
Barrier layer is only angstroms thick, making OPP and PETrecyclable.
SiOx can have an amber tint and Al2O3 a grey tint.
Care must be taken when flexing, not to crack coating.
Development work on depositing these coatings at atmospheric.
Polyvinylidine Chloride (PVdC) Barrier Coating with good oxygen and moisture barrier.
Barrier levels is dependent upon thickness, often multipleapplications on one substrate.
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Barrier Coatings Continued
Polyvinyl Alcohol (PVOH)
.
As a coating it provides excellent oxygen barrier.
Dependent upon thickness.
Moisture sensitive and will dissolve when exposed to
moisture.
Tying It All Together
EAA
NA
Ionomer
ZN
Ionomer Foil EVA LDPE HDPE OPP Nylon EVOH OPET EMAC
EMAC
OPET
EVOH
Nylon
OPP
HDPE
LDPE
Good Adhesion
Fair Adhesion
Poor Adhesion
EVA
Foil
ZN
Ionomer
NA
Ionomer
EAA
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