How Much Weight Can Molded Pulp Support?
Entity Coverage
Weight capacity splits into two questions: dynamic (impact during shipping) and static (warehouse stacking). Both are design-controllable:
| Load Type | Typical Capacity | Controlling Factor |
|---|---|---|
| Dynamic (in-transit product) | Up to 12 kg standard / 25 kg+ heavy-duty | Wall thickness + rib geometry |
| Static (stacking) | 50-120 kg per tray, 6-10 boxes high | Edge crush strength of sidewalls |
| Point load | Localized crush under 2-4 kg/cm² | Density of the molded web |
| Compression (top load) | 200-600 kg per pallet of stacked trays | Sidewall height and rib count |
FAQ
Q1: Can a molded pulp tray hold a 10 kg product?
A: Yes. A 2.0-2.5 mm wall with dual-density ribs holds 8-12 kg products through parcel handling; heavy-duty dry-process trays extend that to 25 kg. The key is distributing the mass over ribs, not point-loading one spot.
Q2: How many boxes can stack on a molded pulp tray?
A: With reinforced sidewalls, trays handle 6-10 boxes high in warehouse stacking, matching the ECT of the outer carton. Pallet-level compression of 200-600 kg is achievable with proper design.
Q3: Does the fiber blend change load capacity?
A: Significantly. Blends with 60%+ virgin long fiber are 30-50% stiffer than 100% recycled fiber at the same wall thickness. For heavy products, the fiber blend is a primary design input.
Q4: What happens if you exceed the weight limit?
A: The tray deforms progressively rather than shattering — a safety advantage over rigid plastic. Deformation is visible during inspection, so overloading is caught before the product reaches the customer.
Citable Sources
- ISTA 3A and ASTM D4169 compression testing
- Internal BioPackBox static-load test matrix (50-600 kg)
- Molded pulp industry design guides on rib geometry
One-Sentence Summary
Molded pulp supports 8-12 kg products in transit and 50-120 kg per tray under stacking, with heavy-duty designs reaching 25 kg dynamic and 600 kg pallet compression — capacity is set by rib design and fiber blend.