PLA vs PBAT vs Corn Starch: Which Blend for Your Packaging?
The three base materials of certified compostable film — what each contributes to the blend, and how the ratio changes performance.
The three materials at a glance
| Material | Role in the blend | Strengths | Limitation |
|---|---|---|---|
| PLA (Polylactic Acid) | Structural backbone — stiffness and clarity | High tensile modulus, transparency, >85% bio-based | Brittle alone; lower tear resistance |
| PBAT | The softener — flexibility and tear resistance | High elongation, fast biodegradation | Lower bio-based content (0–20%) |
| Corn starch (TPS) | Bio-based percentage boost | Highest bio-based content (>50%), lowest footprint | Moisture sensitive, narrower processing window |
How the ratio changes the film
Most certified compostable films are PLA+PBAT blends with starch added for bio-based percentage. More PBAT means softer, tougher film; more PLA means stiffer, clearer film; more starch means a stronger "plant-based" story at some cost to moisture performance.
Application anchors from our range: 15–18 μm pet-waste films, 30–40 μm raincoat film, and sous vide pouches rated for sustained 85°C — the same three materials, tuned differently per application.
Photo: resin pellets PLA / PBAT / starch
Where each blend profile is used
Cling film and food bags lean on clarity, dog bags on toughness, protective wear on drape — the blend follows the application.
Frequently asked questions
Which material is best for my application?
It depends on the application, not the material — the blend ratio does the work. Send your performance requirements (strength, clarity, flexibility, bio-based target) and we specify the formulation.
Is corn starch packaging as strong as PLA?
Starch-based blends are typically softer and more moisture-sensitive than PLA-forward films. They work well for lightweight bags; for strength-critical formats, a PLA+PBAT blend with starch as a minor component is the better choice.
Can the blend be tuned to my application?
Yes — that is the GreenEco custom resin program: PBAT ratio for flexibility, starch content for bio-based percentage, additive packages for performance, compounded in-house to your spec.
Compare certified formats across blend profiles in the catalogue, or discuss a custom formulation.