Barrier coatings for food packaging have become indispensable in today’s market, driven by the dual demands of protecting food products and addressing environmental concerns. As the food packaging industry faces increasing pressure to phase out harmful substances like PFAS and reduce multilayer laminates, innovative barrier coatings are stepping up to preserve food quality while supporting sustainability goals. These coatings play a crucial role in controlling moisture vapor transmission, water absorption, and grease resistance, all key factors in maintaining freshness and consumer satisfaction. This article explores sustainable barrier coating solutions, compares PFAS-free alternatives, and highlights their technical performance, FDA compliance, and practical applications in food packaging.
Why Paperboard Needs Barrier Coatings
Paperboard is a popular material for food packaging due to its renewable nature, but it requires specialized coatings to meet performance standards:
- Moisture Vapor Transmission Rate (MVTR): A critical measure of how much water vapor passes through packaging, with high-performance coatings achieving less than 10 g/100 in²/day to effectively protect food from moisture.
- Water Absorption (Cobb Test): This test measures how much liquid water the paperboard absorbs, with values below 1 g/m² indicating excellent water resistance.
- Grease and Oil Resistance (Kit Test): Rated on a scale from 0 to 12, a score of 10 or above is ideal for food packaging to prevent oil penetration and maintain package integrity.
- Additional Factors: Oxygen transmission rate (OTR) and mineral oil hydrocarbon migration (MOSH/MOAH) control are also vital for advanced packaging quality and food safety.
Popular Barrier Coating Technologies
Several coating technologies are currently used to meet these stringent requirements:
- Emulsion Polymers: Styrene-butadiene and styrene-acrylic emulsions, such as MCP’s Tykote® 1019 and 6161, offer low MVTR and comply with FDA regulations (21 CFR 176.170), providing robust moisture and grease barriers.
- Water-Based Biowax and Polymer Dispersions: Products like Stahl’s Barriertec™ and Mantrose-Haeuser’s VerdeCoat are PFAS-free, FDA/BfR approved, heat-sealable, and recyclable, enabling sustainable packaging solutions without sacrificing barrier performance.
- Next-Generation Dispersions: Innovations like FennoGuard provide compostable coatings compatible with industrial recycling, offering alternatives to traditional polyethylene (PE) and polyethylene furanoate (PEF) barriers.
- Natural Materials: Nanocellulose, shellac, and starch-based coatings demonstrate promising water and grease resistance in lab trials, with emerging bio-based coatings derived from tomato peels (cutin) showing excellent water, oil, and heat sealability while supporting circular economy principles.
Technical Metrics of Barrier Performance
Barrier coatings are evaluated through standardized tests to ensure they meet food packaging demands:
- MVTR/WVTR: Tested per ASTM F1249, with industry targets below 150 g/m²/day for effective moisture control.
- Cobb Test: Measures water resistance; for example, HYDRO-PAK MVTR 4040 achieves a Cobb value around 3 g/m², indicating strong water repellency.
- Kit Test: Assesses oil and grease resistance, with a rating of 12 considered optimal for food packaging applications.
- OTR and MOSH/MOAH: These tests control oxygen ingress and migration of mineral oils, critical for maintaining food safety and quality
Regulatory vs FDA Compliance
FDA 21 CFR 176.170
FDA regulation 21 CFR 176.170 governs substances safely used in food-contact paper and paperboard coatings. Products like Tykote® 6161 comply with these regulations, ensuring they can be safely used across a wide range of food types without risk of harmful migration into food. This compliance is critical for manufacturers to meet U.S. food safety standards and gain consumer trust.
BfR, Blue Angel, EU Flower Certifications
European certifications such as BfR (German Federal Institute for Risk Assessment), Blue Angel, and EU Flower eco-labels set stringent environmental and safety standards for packaging materials. For example, Cartaseal® VWAF meets these certifications, demonstrating compliance with health, environmental, and performance criteria. Blue Angel certification, promoted by the German government, evaluates products from a full life cycle perspective and requires rigorous testing to ensure environmental friendliness and recyclability. Achieving these certifications supports brand sustainability claims and market acceptance in Europe.
Global Compatibility
With no harmonized global standard for food contact coatings, manufacturers must navigate diverse regulations across regions such as the EU, U.S., and Canada. Many markets without local regulations default to EU or FDA standards. Ensuring coatings meet multiple regulatory frameworks simplifies cross-border trade and reduces compliance risks. Collaboration with coating suppliers who provide declarations of compliance and support comprehensive testing is essential for global market access.
Product Use Cases vs Examples
Tykote® 1019 / 6161
Tykote® 1019 is a carboxylated styrene-butadiene emulsion polymer providing strong film strength and excellent moisture, oil, and grease resistance, ideal for food packaging applications requiring durable barrier properties. Tykote® 6161, a flexible acrylic emulsion, offers superior oil and grease resistance while maintaining good moisture barrier performance, making it suitable for packaging frozen foods, snacks, and bakery items.
Cartaseal® OGB F10, SCR, VWAF
Cartaseal® OGB F10 is a PFAS-free, water-based oil and grease barrier coating that replaces traditional fluorochemicals and polyethylene. It is FDA and BfR compliant, heat-sealable, recyclable, and repulpable, enabling sustainable packaging solutions without compromising barrier performance. Its advanced formulation provides exceptional grease resistance even after folding, ideal for fast food containers and takeout packaging.
FennoGuard (Kemira)
FennoGuard is a next-generation dispersion barrier coating designed for high recyclability and compostability. It replaces fossil-based chemistries with bio-based raw materials, supports industrial composting, and breaks down easily during repulping, reducing reject rates in recycling mills. FennoGuard is well-suited for mono-material fiber-based packaging, such as fresh produce and dry goods.
HYDRO-PAK MVTR 4040
HYDRO-PAK MVTR 4040 is a recyclable, water-based barrier coating that achieves a low Moisture Vapor Transmission Rate of approximately 7 g/m²/day and a Kit test rating of 12, indicating optimal oil and grease resistance. It is FDA and EU compliant, heat-sealable, and maintains printability with water-based inks. Applications include food packaging, egg cartons, fresh herb packaging, and bread bags, where moisture and grease barriers are critical.
Application Methods for Coatings
On-Machine Coating
On-machine coating integrates barrier coatings directly on paper machines or pilot lines, offering cost-effective production with reduced handling and faster throughput. This method is ideal for large-scale manufacturing and ensures consistent coating application.
Off-Machine Coating
Off-machine coating uses flexographic or gravure printing followed by oven drying, allowing precise control of coating thickness and multi-layer applications. It is commonly used in contract manufacturing or smaller production runs where flexibility is needed.
Flexographic vs Digital Printing Integration
Barrier coatings can be combined with flexographic or digital printing processes to add functional and aesthetic features. This integration supports customization, branding, and enhanced barrier properties in a single production step.
On vs Off-Machine Comparison
On-machine coating offers scalability and cost advantages but may have limitations in coating complexity. Off-machine coating provides greater flexibility and precision but can increase costs and processing time. Choosing the right method depends on production scale, coating complexity, and product requirements.
Sustainability vs Recyclability
PFAS-Free vs Compostable Coatings
Due to growing health and environmental concerns, many regions including Europe, Denmark, and New York State have banned PFAS in food packaging. PFAS-free coatings like Cartaseal® OGB F10 and FennoGuard offer effective alternatives that comply with these bans while maintaining barrier performance. Compostable coatings support circular economy goals by enabling packaging to biodegrade in industrial composting facilities.
Recyclability vs Repulpability
Recyclability is a key factor for fiber-based packaging sustainability. Coatings must allow for efficient repulping to recover fibers without generating high reject rates. FennoGuard’s dispersion barrier coatings demonstrate excellent repulpability with low reject percentages, supporting closed-loop recycling systems. Properly designed coatings ensure compatibility with existing recycling infrastructure.
Green Certifications vs Eco-Labels
Eco-labels such as Blue Angel and EU Flower validate the environmental credentials of barrier coatings and packaging. These certifications require compliance with strict criteria on raw materials, recyclability, and environmental impact across the product life cycle. They enhance consumer trust and support brand sustainability commitments.
Real-World Implementation Advice
Choose the Right Coating Based on Application
Select coatings by evaluating key barrier needs moisture, grease, oxygen, or mineral oil resistance alongside shelf life and storage conditions. Tailoring the coating to the product and environment ensures optimal performance.
Run Pilot Trials and Scale-Up Tests
Conduct pilot runs and accelerated aging tests with R&D partners or certified labs to validate coating performance under real-world conditions. This reduces risk and ensures consistency during scale-up.
Integrate Quality Control and Regulatory Testing
Implement routine testing aligned with FDA, TAPPI, and ASTM standards to monitor barrier properties and migration limits. This ensures ongoing compliance and product safety.
Document Sustainability Performance
Track and report sustainability metrics such as recyclability, compostability, and life cycle benefits. Use case studies and certifications to communicate environmental advantages to customers and regulators.
Conclusion
PFAS-free barrier coatings offer a compelling combination of technical excellence, regulatory compliance, and sustainability. They protect food quality by controlling moisture, grease, and oxygen ingress while meeting stringent global regulations and supporting circular economy goals. Packaging manufacturers are encouraged to partner with specialists like Kimecopak for sample testing and to develop custom FDA-compliant coatings. By embracing these innovative solutions, brands can enhance packaging sustainability without compromising product safety or performance.
