Annular nanolayered shrink film 3 26-2018

Structure-Process-Property of Biaxially
Oriented Shrink Film
Pat Thomas
PRThomas Technologies, LLC
International Polyolefin Conference 2018

 Purpose of the paper is connect the dots:
• Structure-Process-Properties of biax oriented shrink film
• Resins-Equipment-Applications
 Specifically the presentation will focus on:
• Material:
 Nova Chemical, US Patent: 6,340,532: 2002
Shrink Film
• Equipment
 Sealed Air’s US Patent: 8,012,572: 2011
Microlayering die technology
 Schirmer’s US Patent: 8,870,561: 2014
Nanolayering die technology
Introduction

 Biax shrink film shrinks around a product when heated closed to the
melting point
 Typical resins used to manufacture shrink films include:
• Polyvinyl chloride (PVC)
• Polypropylene (PP)
• Linear-low density polyethylene (LLDPE)
• Low density polyethylene (LDPE)
• High density polyethylene (HDPE)
• Copolymers of ethylene and vinyl acetate (EVA)
• Copolymers of ethylene and vinyl alcohols (EVOH)
• Ionomers (e.g. Surlyn™)
• Copolymers of vinylidene chloride (e.g. PVDC, SARAN™)
• Copolymers of ethylene acrylic acid (EAA)
• Polyamides (PA)
Introduction – Basic Shrink Film

 End Use Applications Include:
• Food packaging; Oxygen and moisture barrier bag:
 Frozen poultry
 Primal meat cuts
 Processed meat and cheese products
• Non-Food packaging; overwraps:
 Compact disks
 Audio/video tapes
 Computer
 Software boxes
 Magazines
 Confectionery
 Others
Introduction – Shrink Film

 Key Critical Properties of Shrink Film Include:
• Free Shrink
• Shrink Force
• Dart Impact
• Tear Strength
• Stiffness
• Haze
• Gloss
• Burn Through Resistance, melt strength
 Biax Shrink Film Manufacturing Processes Include:
• Tenter Frame
• Double bubble blown film
• Triple bubble blown film
Introduction- Shrink Film

 Both Material and Die Technology information is organized
as outlined below:
• Objective
• Experimental Procedure
 Resins
 Equipment Description
 Process Conditions
 Trial Design: Variables
• Results
• Discussion
• Conclusion
Introduction

Structure-Process-Property ultimately determines Film Properties
Introduction
Resin Characterization Equipment Design Process Conditions
MW
MWD
Branching
Crystallinity
Functionalit
y
Screw Design
Die Design
Die Gap
Cooling
Blow-Up Ratio (BUR)
Drawn Down Ratio
Frost Line Height
Specific Output
Film Properties
Structure Process

TRANSITION
MATERIAL:
DUAL REACTOR SOLUTION
LLDPE DEVELOPMENT

 BACKGROUND
• At E.I. DuPont Clysar, Developed and patented a
monolayer LLDPE shrink film to compete against Sealed
Air’s D-955 coex shrink film
• At Dow Chemical, Developed PE resins
• At Nova Chemical, served as Technical Manager
 Dual reactor solution LLDPE development project
• Sealed Air was Nova’s a development partner in this
project
Dual Reactor Solution LLDPE Development

 In 2002 the following LLDPE resins existed:
• ZN-LLDPE
 Organoleptic issues – low MW fraction
 Inferior impact strength
• mLLDPE
 Good organoleptic and impact strength
 Inferior tear strength
 Low melt strength, bubble stability issues
 Nova’s Objective:
• Develop a LLDPE resin to mitigate deficiencies
Introduction
- Non-Uniform
mLLDPE - Uniform

 Produce experimental resins on dual reactor process:
 Fabricate experimental films on Soten’s double bubble
blown film equipment
 Analyze physical properties, present results to develepment
partner
 Evaluate experimental film on typical packaging equipment
Experimental Procedure

 Dual Reactor Solution Process Variables:
• Number of reactors: Dual or Single
• Catalyst: Advanced vs Existing
• % Comonomer: Rx1, Rx2, Both
• Reactor Stirring Tech: Experimental vs Existing
 LLDPE Resin Characteristic Variable Targets:
• Melt Index (g.10 min): 0.5; 1.0
• MWD (SEx): 1.37, 1.35, 1.40, 1.29
• Density (g/cc): 0.920, 0.914
• COHO ratio: 4.4, 3.7
Experimental Procedure: Trial Design

Experimental Procedure: Resins
Resin 1 Resin 2 Resin 3 Resin 4 Resin 5
Experimental Resin R1 R2-c R3 R4 R5
Description Dual RX Dual RX Dual RX Single RX Single RX
High C8 in Rx1 Low C8 in Rx1 C8 in Rx1 & Rx2
MI2 (g/10 min) 0.50 0.57 0.57 1.00 0.50
Density (g/cc) 0.9195 0.9202 0.9141 0.9210 0.9190
MWD (S E x) 1.37 1.35 1.40 1.34 1.29
COHO** 4.4 3.7 4.7 3.7 4.4

Experimental Procedure: Resin
Comonomer Content in High Molecular Weight Region
GPC-TREF Technique
4
6
8
10
12
14
16
5 5.2 5.4 5.6 5.8 6
Log Molecular Weight
#ofBranches/1000Carbons
Dual Rx - High C8
Dual Rx - Low C8
11G1
Molecular Weight = 350,000
Single Rx
Log Molecular Weight
#ofBranches/100carbonatoms
GPC-TREF Plot
Comonomer Content in High MW Region
5.0 5.2 5.4 5.6 5.8 6.0
0.4
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
Single Rx
Old Catalyst
Adv CatalystAdv Catalyst
Adv Catalyst

Soten Double Bubble Blown Film Line
Experimental Procedure:
Equipment Description

Extruder Layer Diameter L/D
1. External 50mm (1.97 in) 38
2. Intermediate 60mm (2.36 in) 32
3. Central 70mm (2.75 in) 33
4. Intermediate 60mm (2.36 in) 32
5. Internal 50mm (1.97 in) 38
Die Size 240 mm (9.45 in)
Die gap 1.5 mm (60 mil)
Air Ring 1 high pressure
Air Ring 2 low pressure, high volume
Air Ring 3 low pressure, high volume

Blown Film Process Conditions
Barrel Zones 180 - 230 C (356 - 446 F)
Die 220 C (428 F)
Melt Temp. 225 C (437 F)
Cooling Water 15 C (60 F)
Cooling Air 10 C (50 F)
Stretch Ratio 5 X 5
Orient. Temp 101 C (213 F)
Output (Kg/hr) 100 (220 lbs/hr)
Lay Flat 1700 mm (67 in)

Shrink Packaging Trial
 Shrink Wrapped Booklets
 Shrink Tunnel: Elantech
 Experimental films evaluated:
• Oven Temperatures:
 125 C, 150 C, 175 C, 200 C
• Conveyer belt speed range:
 2 to 42 fpm

Shrink Packaging Trial
 Defects:
• Dog Ears, Wrinkles
• Burn-Through
 Results reported:
• Min and Max conveyor speed
 Achieved “Perfect” packages
at each temp.
 Represents the Processing
Window

Film Physical Properties Results
Description High C8 in Rx1 Low C8 in Rx1 Low C8 in Rx1 1 Rx 1 Rx
MI2 (g/10 min) 0.5 0.57 0.57 1 0.5
Density (g/cc) 0.919 0.9202 0.9141 0.921 0.919
MWD (S E x) 1.37 1.35 1.4 1.34 1.29
COHO** 4.4 3.7 4.7 3.7 4.4

MI2 (g/10 min) 0.5 0.57 0.57 1.0 0.5
Density (g/cc) 0.9195 0.9202 0.9141 0.921 0.919
MWD (S E x) 1.37 1.35 1.4 1.34 1.29
COHO** 4.4 3.7 4.7 3.7 4.4

MI2 (g/10 min) 0.5 0.57 0.57 1.0 0.5
Density (g/cc) 0.919 0.9202 0.9141 0.921 0.919
MWD (S E x) 1.37 1.35 1.4 1.34 1.29
COHO** 4.4 3.7 4.7 3.7 4.4

Description High C8 in Rx1 Low C8 in Rx1 Low C8 in Rx1 1 RX 1 Rx
MI2 (g/10 min) 0.5 0.57 0.57 1.0 0.5
Density (g/cc) 0.9195 0.9202 0.9141 0.921 0.919
MWD (S E x) 1.37 1.35 1.4 1.34 1.29
COHO** 4.4 3.7 4.7 3.7 4.4

Shrink Packaging Performance
Experimental Resin R1 R2-c R3 R4 R5 C1 C2 C3 C4
Description High C8 in Rx1 Low C8 in Rx1 Low C8 in Rx1 Single RX Single RX Single RX Single RX Film 1 Film 2
MI2 (g/10 min) 0.50 0.57 0.57 1.00 0.50 0.72 1.00 Coex Monlayer
Density (g/cc) 0.920 0.920 0.914 0.920 0.920 0.920 0.920 Crosslinked Crosslinked
MWD (S E x) 1.37 1.35 1.4 1.34 1.29
COHO** 4.4 3.7 4.7 3.7 4.4
Dual RX solution resins perform
better than commercial shrink film
products, except R4

 The experimental films exhibit excellent physical properties
Note: Experimental films are not:
• Multilayer structures
• Cross-linked
 As a result of this work, ZN-LLDPE Product Line was
developed, patented and commercialized
• $1 Billion investment
• 1 Billion lbs./yr. capacity
• Specifically, LLDPE (1.0 MI, 0.920 g/cc) for shrink film
applications
Conclusions

Resin: How It Works
Control of MWD with Multiple Reactors

Different but Distinct species in each reactor - influence the position and
concentration of the MW component of the polymer structure

Resin Structure: Conventional vs Bimodal

Resin Structure can be optimized by controlling MI, Density, MWD of each species in the dual
reactor process
•Reactor split controls the overall MWD
•C8 added to RX1 (High MW fraction) to improve strength
•Smaller amount of RX2 (Low MW fraction) to reduces organoleptic and smoke issues
Taste,
Odor,
Smoke,
Migration
Processability
Lubrication
Mechanical
Strength,
Tie Molecules
Processability,
melt strength,
orientation
development
Conventional
Bimodal
1 2 3 4 5

TRANSITION
EQUIPMENT DESIGN
ANNULAR MICROLAYERING
DIE TECHNOLOGY

 Sealed Air’s Objective:
 Internally develop the annular microlayering die technology in
order to establish a competitive advantage in manufacturing:
• Thinner films
• Superior performance
• Less raw materials used
• Significant cost reduction
Annular Microlayered Shrink Film
Sealed Air Patent: 8,012,572

Microlayered Die DesignDownward Blown Film Line
Conventional die plates
Microlayer die plates

Die Plate
Spiral flow with
leakage towards the
center of the die
onto an internal
mandrel

 Resin variables in microlayers:
• LLDPE O-LLDPE, H-LLDPE, B-LLDPE
• EVA; %VA 2.5, 3.3, 8.5, 20.0
• VLDPE; Density 0.900, 0.906, 0.912
• PE vs PS
• Type and % Repro PE, PP, PA
 Film Structures Variables:
• Conventional VS Microlayer Coex 3, 5 layer; 25 microlayers
• Film Thickness (mils) 0.6, 0.3
 Microlayered Film Formulations Variables: Note: M1 and M2 alternated and repeated
• Microlayer 1: LDPE, VLDPE, LDPE+VLDPE, LLDPE+Repro
• Microlayer 2: MDPE, VLDPE, MDPE+LLDPE,
LLDPE+ Repro, SBS, VLDPE+LLDPE
 Orientation: 5x5, 6x6
Resins, Formulations, and Film Structures

Resins
Reference
Resin Type MI (g/10 min) Density (g/cc) Melt Temp % VA
Dowlex 2037 MDPE-1 2.5 0.935 124.7
FL M3105 MDPE-2 2.2 0.936
Dowlex 2036G MDPE-3 2.5 0.937 125.0
Flint Hill EVA 1335 EVA-1 2.0 0.924 104.7 3.3
Westlake EF347AA EVA-2 2.0 0.925 2.5
Escorene LD318.92 EVA-3 2.0 0.930 8.7
Escorene LD761.36 EVA-4 5.7 0.950 72.0 20.0
Exceed 1012CA VLDPE-1 1.0 0.912
Affinity PF 1140G VLDPE-2 1.6 0.899 96.1
Affinity PL 1881G VLDPE-3 1.0 0.906 100.0
Exact 3132 VLDPE-4 1.2 0.900 96.0
Attane 4203 VLDPE-5 0.8 0.907 122.8
Styroflex 2G 66 SBS-1 12.5 1.000
Styroflux HS 70 SBS-2 13.0 1.020
Dowlex 2045 O-LLDPE-1 1.0 0.920 122.2
Exxon LL3001 H-LLDPE-2 1.0 0.917 125.0
Westlake SC75858 H-LLDPE-3 0.5 0.917 121.0
LL1001.32 B-LLDPE-4 1.0 0.918 121.0
Repro-1 93% O-LLDPE 6% EVA 1% additives
Repro-2 22% PP 8% LLDPE 20% z-Surlyn 15% g-PE 24% PA 6+6/66 10% EVA
Repro-3 50.6 LLDPE 13.5% LDPE 30% PA 6 5.9% EVA

Film Formulations - Reference
Film Micro-1 Micro-2 Thickness (Mils)
F1 Conventional LLDPE-1+MDPE-1 0.3
F2 Conventional LLDPE-1 0.3
F3 Conventional LLDPE-1 0.6
F4 LLDPE-1+MDPE-1 LLDPE-1 0.3
F5 LLDPE-1 LLDPE-1+Repro-2 0.3
F6 VLDPE-3 LLDPE-1+MDPE-1 0.3
F7 LLDPE-1 MDPE-2+LLDPE-1 0.3
F8 LLDPE-2+VLDPE-1 LLDPE-2 0.3
F9 LLDPE-3+VLDPE-4 LLDPE-3 0.3
F10 VLDPE-5+LLDPE-1 LLDPE-1 0.3
F11 VLDPE-5 LLDPE-1+MDPE2 0.3
F12 LLDPE-1+VLDPE-2 LLDPE-1+VLDPE-2 0.3
F13 LLDPE-1 MDPE-1+LLDPE-1 0.3
F14 LLDPE-1 LLDPE-1 0.3
F15 LLDPE-1 VLDPE-1 0.3
F16 LLDPE-1 LLDPE-1 0.3
F17 LLDPE-1 LLDPE-1+REPRO-1 0.3
F18 LLDPE-1+REPRO-1 LLDPE-1+REPRO-1 0.3
F21 LLDPE-1 VLDPE-1 0.3
F22 VLDPE-2 SBS-2 0.3
F23 VLDPE-3 LLDPE-1 0.3
F24 EVA-3 MDPE-2 0.3
F25 VLDPE-1 LLDPE-2 0.3

Microlayered Film Example
Ratio of Bulk Layer Thickness to Microlayer Thickness Range: 1:2 to 1:40
Microlayer 1 and Microlayer 2
are alternated and repeated
13
Microlayers
12
Microlayers
Microlayers
Bulk Layers
Bulk Layers

 F1-F3 Conventional film; 3 and 5 layer coex
 F3 is 0.6 mil, all others 0.3 mils thick
 F4, F10, F11, and F12 have greatest difference in alternating “Hard/”Soft”
layers
 F1 and F4: same resins; Conventional vs Microlayered
Annular Conventional vs Microlayer Shrink Film
Microlayered
Conventional vs Microlayer
Same Resins: MDPE/LDPE Greatest difference between
“Hard” – “Soft” Layers

 The major attribute in the finished film:
Create an “I-beam” effect by
alternating and repeating “hard/soft”
layers
 The repeated layering of two materials
with a different properties can create a
new film that can exceed the average or
the maximum value of the individual
layers.
 Normally “I” beam effect is applied to
the tensile strength characteristics
• However, with nanolayered film the
I-beam effect improves:
 Tear
 Puncture
 Elongation
 Secant modulus

 F3: Conventional at 0.6 mils, F4 –F25 microlayered at 0.3 mils
 F4 microlayered at half the thickness of F3 but equivalent Tear
 F4 microlayered with alternating “Hard” / “Soft” layers, also F10, F11, F12
 F2 and F3: Same resins, Conventional 0.30 and 0.6 mils respectively, half the thickness and half
the tear
0.6 mils Conventional vs 0.3 mils
Microlayer Microlayered: Hard/Soft alternating layers

 Sample F1-F3 fabricated with standard annular plate die, 3 or 5 layers
 F3 is 0.6 mils conventional film; All others 0.3 mils thick
 F4 – F25 Microlayered Film
 F13, F14, F15 oriented 6X6
Oriented 6X6; others 5x5
F3 0.6 mils Conventional vs F4 0.3 mils Microlayer

F1-F3 fabricated with standard annular plate die
F3 conventional 0.6 mil film; F4 – F25 microlayered 0.3 mil film
F3 has superior impact strength as compared to thinner or microlayered films

 F10, F11, F12 have the greatest difference in Hard/Soft alternating microlayers
 F17, F18, F19 have repro included

 F17, F18, F19 have
Repro-1 included:
Film Micro-1 Micro-2
F17 100% LLDPE 10% LLDPE
90% Repro-1
40% Repro-1 80% Repro-1
F19:
•50% LLDPE
•50% Repro-1
•Both M1 and M2

F9 50% Exact 3132 100%Westlake SC75858
50% Westlake SC75858
F10 50% Attane 4203 100% Dowlex 2045
50% Dowlex 2045
F11 100% 4203 60% Dowlex 2045
40% Dowlex 2037
F12 60% Dowlex 2045 50% Dowlex 2045
40% Affinity 11PF 1140G 50% Dowlex 2037
Internal Microlayers effect surface property
Resin Type MI Density
Dowlex 2045 O-LLDPE 1 0.92
Westlake SC75858 H-LLDPE 0.5 0.917
Dowlex 2037 MDPE 2.5 0.935
Attane 4203 VLDPE 0.8 0.907
Affinity PL 1881G VLDPE 1 0.906
Exact 3132 VLDPE 1.2 0.9
Affinity PF 1140G VLDPE 1.6 0.899

F17, F18, and F19 contain Repro-1
•93% O-LLDPE
•6% EVA
•1% Additives
90% Repro-1
50% LLDPE
50% Repro

1. Microlayered film:
• 50% thinner than conventional film
• Equivalent physical properties
2. Layer sequencing microlayers creates I-beam effect which significantly
improves physical properties
3. Less expensive material could be substituted without sacrificing performance
4. More reclaimed material can be added without sacrificing performance
5. Thinner layers of expensive material (EVOH, PA, Tie Resins) with equivalent
barrier performance
6. To connect the dots: Commercial dual reactor ZN-LLDPE – used in
microlayered film structures
Annular Microlayered Shrink Film
Conclusions

TRANSITION
EQUIPMENT DESIGN
ANNULAR NANOLAYERING
DIE TECHNOLOGY

• US Patent: 6,413,595, Schrimer, 2002
– Modular Disc Co-extrusion Die
• US Patent: 8,870,561, Schirmer, 2014
– Layer Sequence Repeater Module (LSR) for the Modular Disc
Co-Extrusion Die
– Patents awarded
• USA
• Canada
• Europe
• China
History & Design of the
Annular Nanolayering Modular Disc Die

• A Nanolayer is an order of magnitude thinner than a
microlayer
Microlayer vs Nanolayer
Practical limit for Microlayer
Practical limit of nanolayering is 100
times thinner than microlayering!
Microns Mils
3 1.118
0.03 0.001Practical limit for Nanolayer

Annular Nanolayering Film Technology
Die Design
• Modular Disc Die Design
• Layer Sequence Repeater
All Microlayers
All Nanolayer

• Nanoscale confinement demonstrates dramatic
changes in crystallization
• Confined crystallization of polymers leads to the
formation of oriented lamellae in nanolayered films
• The oriented lamellae increase the tortuitous
pathway with increasing the lamellar orientation
thereby improving the barrier performance
• As the layer thicknesses approached a few
nanometers, lamellar morphologies in HDPE layers
resembled “single crystal” structures
• Note: the results of nanolayering film depends on
material used
Nanolayering Mechanism
Gas Barrier Properties

Commercially Available Annular
Nanolayer Blown Film Line
Commercial 82 Layer Nanolayer Blown Film Line

• Annular Nanolayer Die Technology commercially available
• Annular Nanolayering technology provides equivalent or greater capabilities
as compared to Microlayering technology
– Microlayering is limited to 29 layers
– Nanolayering is limited to greater than 29 layers
• Microlayering/Nanolayering technology is applicable in the following film
processes:
– Blown Conventional, Double Bubble, Triple Bubble, Downward Water Quench
– Cast Conventional, Round Cast (Downward Water Quench)
– MDO
– Tenter Frame Sequential, Simultaneous
– Extrusion Coating, Laminations
Annular Nanolayer Film Summary

Annular nanolayered shrink film 3 26-2018

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