1
1 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Optimization of peelable packaging using DoE
Presented by:
Ina SchreibFraunhofer Institute for Process Engineering and Packaging IVV
Branch Lab Processing TechnologyDresden, Germany
16TH TAPPI EUROPEAN PLACE CONFERENCE
2 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Introduction
Challenge to ensure safe closure and at the same time convenient opening behavior
Choosing the most suitable film and the regarding parameter settings takes a lot of time and material for testing
Considering special requirements when using DoE for optimization of peelable packaging
Easy toopen
Safe closure
2
3 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Packaging concept:
Peelable tray for cold cuts
Films:
Cover film: PET/PE-PA-EVOH-PA-PE 62 μm
Tray film: APET/PE-EVOH-PE peel 300 μm
Sealing conditions:
Heat conductive sealing
Flat jaws 2.5 mm vs. 5 mm (upper jaw heated)
Considering contamination
Material
4 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Define design space:
Input parameter: Sealing time, temperature, pressure
Limits (chosen depending on packaging process and film specification)
Temperature upper jaw: 145 °C to 174 °C
lower jaw: tempered to 50 °C
Time: 1.5 s to 2.5 s
Pressure: 0.8 N/mm² to 2.6 N/mm²
Set up an experimental design:
I-Optimal design with 20 runs
150 160 170
1.62.0
2.41.2
1.6
2.0
2.4
Time (s)
Pressure (MPa)
Temperature (°C)
0.8
2.6
Method
3
5 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Performing experiments
Seal samples with and without contamination
Measure seal strength values
Method
Sealing tool
Film sample
40
Contaminated area50
15
*IVLV Technical Bulletin No. 114/2019 “Method for analyzing the influence of contamination on seal properties of films for packaging applications”
6 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
T-Peel Test(ASTM F88, DIN 55529)
0
5
Seal strength (N/8 mm)
* Dr. Jérome Pascal “Ultra versatile adhesives to broaden the possibilities of extrusion lamination” TAPPI PLACE Conference 2006, Cincinnati
Method – Peel strength measurement
Opening
Shear modeOpening
4
7 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
180°
Fixed-Arm Peel-Test(ASTM F2824, DIN 55409-02)
T-Peel Test(ASTM F88, DIN 55529)
135°
0
5
Seal strength (N/8 mm)
Method – Peel strength measurement
8 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
DIN SPEC 91441 “Test Method for Determination of Peel Strength” (publication expected in October 2019)
Constant peel angle 135 °
Method – Peel strength measurement
135 °
22,5 °
Equilateral triangle
Front of the seam
5
9 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Fitting a combined response surface model for contaminated & uncontaminated seams
Using a desirability function for optimization towards a target value
Target value easy-to-openSeal strength
low
high
0 1 Desirability
Optimization of sealing parameters
10 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Fitting a combined response surface model for contaminated & uncontaminated seams
Using a desirability function for optimization towards a target value
Setting limits
Optimization of sealing parameters
Upper limit maximum acceptable “Easy-to-open” value
Seal strength
low
high
Lower limit transport safety
0 1
Target value easy-to-open
Desirability
6
11 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
0 1 Desirability
Target value for easy-to-openUpper limit
Seal strength
low
high
Lower limit for transport safety
Using easy-to-open guide values for optimization
12 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Source: “IVLV Technical Bulletin No. 106/2011 “Guideline for design of “easy opening” peelable packaging systems”
Children3-5 years old
4 N (10 N)
Guide values »Easy to open«
Children8-10 years old
10 N (21 N)
Adults20-60 years old
17 N (30 N)
Older Adults61-80 years old
11 N (24 N)
Female consumers, plastic tear tab (OPP/PE)
X1 N ( X2 N) X1 … represents 95 % of the consumersX2 … represents 50 % of the consumer
Using easy-to-open guide values for optimization
7
13 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Source: “IVLV Technical Bulletin No. 106/2011 “Guideline for design of “easy opening” peelable packaging systems”
Older Adults61-80 years old
11 N (24 N)
Guide value for theopening forceMax. peel line
∗
Targetvalueforsealstrength ∗ 0.46N/mm
Using easy-to-open guide values for optimization
14 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Ensuring seal integrity during transportwith lower seal strength limit
0 1 Desirability
Target value for easy-to-openUpper limit
Seal strength
low
high
Lower limit for transport safety
8
15 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Random vibration Vertical shock Horizontal impact DropTest procedure
Loads during transport Loads during manual handling
Ensuring seal integrity during transportwith lower seal strength limit
16 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Ensuring seal integrity during transportwith lower seal strength limit
9
17 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Ensuring seal integrity during transportwith lower seal strength limit
Seal failurecausedby droppingthe box
18 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Ensuring seal integrity during transportwith lower seal strength limit
Determine seal strength that withstands critical loads
Drop height: 300 mm and 600 mm
Amount of drops: 1 to 3
Seal strength level: low, middle and high
10
19 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Position
Failure
lowest
middle
highest
Seal strength
Ensuring seal integrity during transportwith lower seal strength limit
Lowest stress level
300 mm height
1 drop
20 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Position
Failure
lowest
middle
highest
Seal strength
Ensuring seal integrity during transportwith lower seal strength limit
Highest stress level
600 mm height
3 drops
Result: lower seal strength limit = 0.4 N/mm
11
21 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Ensuring seal integrity during transportwith lower seal strength limit
22 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Target value: 0.46 N/mm Upper limit: 0.5 N/mm
Optimal settings: 1.55 N/mm², 165 °C, 1.9 s
Lower limit: 0.4 N/mm
174
148
161
Tem
pera
ture
(°C)
2.5
1.5
2.0
Tim
e(s
)
148 174161
Pressure (N/mm²)Temperature (°C)0.8 2.61.7
Results: Predicted process window
2.5
1.5
2.0
Tim
e(s
)
Pressure (N/mm²)0.8 2.61.7
Clean
Contaminated
Fit for both
optimal settings
12
23 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Target value: 0.46 N/mm Upper limit: 0.7 N/mm
Optimal settings: 1.55 N/mm², 165 °C, 1.9 s
Lower limits: 0.4 N/mm
Clean
Contaminated
Fit for both
174
148
161
Tem
pera
ture
(°C)
2.5
1.5
2.0
Tim
e(s
)
148 174161
Pressure (N/mm²)Temperature (°C)0.8 2.61.7
optimal settings
Results: Predicted process window
2.5
1.5
2.0
Tim
e(s
)
Pressure (N/mm²)0.8 2.61.7
Guide value for adults
24 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Peelable packaging permits only a small seal strength range for both easy-to open and safe closure
Response surface method is a good opportunity to predict process windows for packaging (sealing) process
Easy-to-open values available as a guideline
Lower limits crucial for transport safety
Conclusions
13
25 Ina Schreib, Fraunhofer IVV – Optimization of Peelable Packaging - 17th TAPPI European PLACE Conference 2019 Porto - Session 7 - Paper 3
Presented by:
Ina Schreib - Sealing and Welding Processes -Fraunhofer IVVBranch Lab Processing [email protected]