What Is PHA Coating?
PHA (Polyhydroxyalkanoate) is a biodegradable polyester produced by bacterial fermentation of renewable feedstocks. When applied as a coating on paper, PHA creates a barrier layer that is both functional and fully compostable — including in home composting conditions.
Unlike PLA (Polylactic Acid), which requires industrial composting at elevated temperatures, PHA can biodegrade in ambient environments including soil, freshwater and marine conditions. This makes PHA-coated paper a compelling choice for brands seeking end-of-life certainty in their packaging.
How PHA Coating Compares to Other Technologies
| Property | PHA Coating | PLA Coating | Water-Based Coating | PE Extrusion |
|---|---|---|---|---|
| PFAS-Free | ✓ | ✓ | ✓ | ✓ |
| Home Compostable | ✓ | ✗ | Depends | ✗ |
| Industrial Compostable | ✓ | ✓ | Depends | ✗ |
| Recyclable (paper stream) | Depends | ✗ | ✓ | ✗ |
| Marine Biodegradable | ✓ | ✗ | ✗ | ✗ |
| Heat Sealable | ✓ | ✓ | ✓ | ✓ |
| Bio-Based Content | ✓ | ✓ | Depends | ✗ |
Key Performance Metrics
- Kit grade: 6-10 (3M Kit test), depending on coating weight and formulation
- Cobb value: <25 g/m², providing reliable moisture barrier
- Heat seal temperature: 130-180°C, suitable for standard packaging equipment
- Coating weight: 5-25 gsm, customizable for barrier requirements
- Operable temperature: -20°C to 120°C for cold chain and hot-fill applications
PHA Product Range
PHA Coated Cupstock Paper
Designed for paper cups and cold/hot beverage containers. PHA coating provides leak-proof performance while enabling full compostability. View Product →
PHA Coated Greaseproof Paper
Suitable for fast food wrappers, deli papers and interleaving sheets where grease resistance is critical. View Product →
PHA Coated Lunchbox Paper
For takeaway containers and food trays, offering both oil and moisture barrier with compostable credentials. View Product →
PHA Coated Heat Seal Paper
Provides heat-sealable layers for sachet, sachette and flow-pack applications. View Product →
PHA Coated Kraft Paper
Available in bleached and unbleached versions for eco-friendly wrapping and bag applications. View Coated Kraft →
PHA Coated Art Paper
For premium print applications such as luxury packaging and branded folding cartons. View Product →
Applications
- Food service: Cups, containers, trays, plates for takeaway and food courts
- Fast food packaging: Burger wrappers, sandwich wraps, fry cartons
- Bakery: Pastry bags, cake boards, baking cups, interleaving sheets
- Confectionery: Chocolate and candy wrapping requiring grease resistance
- Fresh produce: Trays and containers for fruits and vegetables
Compostability Certifications
PHA coatings can achieve the following certifications depending on formulation and substrate:
- OK Compost HOME (TÜV Austria) — certifies home compostability
- OK Compost INDUSTRIAL (TÜV Austria) — certifies industrial compostability
- ASTM D6400 / EN 13432 — international compostability standards
- FDA 21 CFR 176.170 — food contact compliance
FAQ
Is PHA coating really compostable at home?
Yes. Unlike PLA which requires 50-60°C industrial composting conditions, PHA can biodegrade at ambient temperatures in home compost bins within 6-12 months.
Can PHA-coated paper be recycled?
Some PHA-coated papers can be repulped, but recycling compatibility depends on the coating weight and formulation. Composting is the recommended end-of-life pathway.
Is PHA coating more expensive than PE?
PHA coating is currently more expensive than conventional PE extrusion coating, but costs are declining with production scale. The premium is offset by compostability benefits and regulatory compliance advantages.
What temperatures can PHA coated paper withstand?
PHA coated papers are suitable for temperatures from -20°C (freezer) to 120°C (hot-fill). For microwave applications, please consult our technical team for specific recommendations.
Can I test PHA coated paper on my packaging line?
Yes. We offer sample rolls for machine trials. Contact us with your packaging specifications for a compatibility assessment.