Investigation and Comparison of Alternative Oxygen Barrier Coatings for Flexible PP Films as Food Packaging Material
Abstract
:1. Introduction
2. Materials and Methods
2.1. Materials
2.1.1. Substrate Films
2.1.2. Coating Agents
2.2. Methods
2.2.1. Preparation of CBS004
2.2.2. Preparation of PVOH
2.2.3. Coating Method and Conditions
2.3. Characterization
2.3.1. Determination of Oxygen Transmission Rate
2.3.2. Determination of Degree of Crosslinking
3. Results and Discussion
3.1. Oxygen Barrier Properties
3.1.1. Single Coating
- PP/SiOx, OPP/AlOx
- CPP70
3.1.2. Double Coating
3.1.3. Effect of ORMOCER® Curing Conditions on Oxygen Barrier Properties
3.1.4. DSC Analysis for Degree of Crosslinking
4. Conclusions
- Combining SiOx and AlOx with ORMOCER®, Michem® Flex, and PVOH resulted in high oxygen barrier properties for PP/SiOx and OPP/AlOx films.
- Deposition of a single layer of ORMOCER® improved the oxygen barrier property of uncoated CPP70 by approximately 95%. Under different curing conditions, OTR values in the range of 10–100 cm3/m2·d·bar were achieved. Optimization of the curing conditions further improved the barrier performance by approximately 98% and reduced the OTR within this range.
- Increasing the wet thickness of the ORMOCER® coating from 15 µm to 40 µm improved the oxygen barrier performance of CPP70 by a factor of 1.72, with the OTR value changing from 30 cm3/m2·d·bar to 17.41 cm3/m2·d·bar.
- The OTR value at the semi-industrial coating scale correlated well with the laboratory scale, showed consistency between the two processes, and indicated that ORMOCER® could achieve an optimal level of crosslinking under semi-industrial curing conditions.
- Michem® Flex coating resulted in a significant reduction in oxygen permeability and could reduce the OTR value of CPP70 by a factor of 551, from 1516 cm3/m2·d·bar to 2.75 cm3/m2·d·bar.
- The use of ORMOCER® and Michem® Flex as primer coatings in a double coating process improved the adhesion of PVOH and notably improved the oxygen barrier property of CPP70, achieving exceptionally low OTR values (OTR < 0.1 cm3/m2·d·bar).
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Substrate Film | Description | Substrate Thickness (µm) |
---|---|---|
CPP70 | Cast PP with corona discharge | 70 |
PP/SiOx | PP films vapor deposition coated with silicon oxide | 22 |
OPP/AlOx | Biaxially stretched PP film vapor deposition coated with aluminum oxide | 20 |
Substrate | Coating Agent (40 µm wet) | Thermal Treatment |
---|---|---|
PP/SiOx, OPP/AlOx, CPP70 | CBS004 | 100 °C (20 min) |
MCHB3513 | 70 °C (30 min) | |
PVOH | 50 °C (10 min) |
Substrate | Coating Agent | Thermal Treatment | |
---|---|---|---|
First Coating (15 µm wet) | Second Coating (40 µm wet) | First Coating/Second Coating | |
CPP70 | CBS004 | CBS004 | 100 °C (20 min)/100 °C (20 min) |
MCHB3513 | 100 °C (20 min)/70 °C (30 min) | ||
PVOH | 100 °C (20 min)/50 °C (10 min) | ||
MCHB3513 | CBS004 | 70 °C (30 min)/100 °C (20 min) | |
MCHB3513 | 70 °C (30 min)/70 °C (30 min) | ||
PVOH | 70 °C (30 min)/50 °C (10 min) |
Coating Scale | Laboratory | Semi-Industrial | ||
---|---|---|---|---|
Coating speed | 10 mm/s | 83 mm/s (5 m/min) | ||
Curing conditions | Temperature (°C) | Time (min) | Temperature (°C) | Time (s) |
60 | 20 | 100 | 20 | |
80 | 5 and 20 | |||
100 | 5 and 20 | |||
130 | 5 and 20 |
Substrate | Coating Scale | Wet Coating Thickness (µm) | Coating Agent | OTR (cm3/m2·d·Bar) |
---|---|---|---|---|
PP/SiOx | Laboratory | 40 | Uncoated | 0.536 ± 0.259 |
CBS004 | 0.061 ± 0.061 | |||
MCHB3513 | 0.005 ± 0.002 | |||
PVOH | 0.006 ± 0.001 | |||
OPP/AlOx | Laboratory | 40 | Uncoated | 6.134 ± 1.802 |
CBS004 | 0.076 ± 0.054 | |||
MCHB3513 | 0.035 ± 0.050 | |||
PVOH | 0.279 ± 0.470 | |||
CPP70 | Laboratory | 40 | Uncoated | 1516.64 ± 39.17 |
CBS004 | 17.41 ± 1.17 | |||
MCHB3513 | 2.75 ± 1.49 | |||
PVOH | 259.99 ± 69.01 * | |||
Semi-industrial | No information provided | CBS004 | 35.59 ± 7.66 |
Substrate | Coating Agent | OTR | |
---|---|---|---|
First Coating (15 µm wet) | Second Coating (40 µm wet) | (cm3/m2·d·bar) | |
CPP70 | CBS004 | CBS004 | 9.314 ± 1.79 |
MCHB3513 | 0.129 ± 0.04 | ||
PVOH | 0.075 ± 0.10 | ||
MCHB3513 | CBS004 | 0.211 ± 0.33 | |
MCHB3513 | 0.101 ± 0.10 | ||
PVOH | 0.040 ± 0.06 |
Substrate | Coating Scale | Curing Conditions | OTR Improvement | |
---|---|---|---|---|
Temperature (°C) | Time | Percentage (%) | ||
CPP70 | Laboratory | 80 | 5 (min) | 95.0 |
20 (min) | 96.9 | |||
100 | 5 (min) | 97.5 | ||
20 (min) | 98.0 | |||
130 | 5 (min) | 98.2 | ||
20 (min) | 98.0 | |||
Semi-industrial | 100 | 20 (s) | 97.7 |
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Sharbafian, F.; Tosic, K.; Schmiedt, R.; Novak, M.; Krainz, M.; Rainer, B.; Apprich, S. Investigation and Comparison of Alternative Oxygen Barrier Coatings for Flexible PP Films as Food Packaging Material. Coatings 2024, 14, 1086. https://doi.org/10.3390/coatings14091086
Sharbafian F, Tosic K, Schmiedt R, Novak M, Krainz M, Rainer B, Apprich S. Investigation and Comparison of Alternative Oxygen Barrier Coatings for Flexible PP Films as Food Packaging Material. Coatings. 2024; 14(9):1086. https://doi.org/10.3390/coatings14091086
Chicago/Turabian StyleSharbafian, Farshad, Katharina Tosic, Romana Schmiedt, Martin Novak, Michael Krainz, Bernhard Rainer, and Silvia Apprich. 2024. "Investigation and Comparison of Alternative Oxygen Barrier Coatings for Flexible PP Films as Food Packaging Material" Coatings 14, no. 9: 1086. https://doi.org/10.3390/coatings14091086