extrusion coating substrates

7/28/2019 Extrusion Coating Substrates

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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 ..


3/17

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


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


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


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


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


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


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


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


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


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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extrusion coating substrates

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