Optimization of peelablepackaging using DoE

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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 Technologyina.schreib@ivv-dd.fraunhofer.de