Paperboard (also called cardboard or cartonboard) is the foundation material for virtually all gift packaging. Its grade, thickness, and surface treatment directly determine the structural integrity, print quality, and perceived value of the finished box. Understanding paperboard specifications is e
Paperboard (also called cardboard or cartonboard) is the foundation material for virtually all gift packaging. Its grade, thickness, and surface treatment directly determine the structural integrity, print quality, and perceived value of the finished box. Understanding paperboard specifications is essential for selecting the right material for gift-grade folding cartons and rigid boxes.
Paperboard Grade Classification
| Grade | Abbreviation | Layer Construction | Typical GSM | Whiteness |
|---|---|---|---|---|
| Solid Bleached Sulfate | SBS | All bleached virgin fiber | 200–400 | 85–90% |
| Solid Unbleached Sulfate | SUS | All unbleached virgin fiber | 200–400 | 60–70% |
| Clay Coated Newsback | CCNB | White top + recycled gray back | 250–500 | 75–80% (top) |
| Clay Coated Kraft Back | CCKB | White top + kraft back | 250–450 | 75–80% (top) |
| Folding Boxboard | FBB | Multi-ply: bleached top + mechanical middle + bleached back | 250–400 | 80–85% |
| Greyboard (chipboard) | — | Recycled fiber, single ply | 600–2000 | Varies (grey) |
Key Physical Properties
| Property | Test Method | SBS (300 GSM) | FBB (300 GSM) | CCNB (350 GSM) |
|---|---|---|---|---|
| Caliper (mm) | ISO 534 | 0.38–0.42 | 0.42–0.48 | 0.45–0.52 |
| Burst strength (kPa) | ISO 2759 | 350–450 | 300–380 | 250–350 |
| Bending stiffness MD (mN·m) | ISO 5629 | 12–18 | 15–22 | 10–15 |
| Surface smoothness (Sheffield) | TAPPI T538 | 20–40 | 50–80 | 80–120 |
| Brightness (%) | ISO 2470 | 85–88 | 80–85 | 72–78 |
Surface Coating Options
- Aqueous coating: Water-based, provides moderate gloss (40–60 GU at 60°). Cost-effective, recyclable. Scratch resistance: 3–4 cycles (Sutherland rub test). Drying time: instant under IR.
- UV coating: High gloss (80–90 GU) or matte (10–20 GU). Superior scratch and rub resistance (50+ cycles). Requires primer for porous boards. Not recyclable in standard paper streams — must be removed during repulping.
- Lamination (film laminate): Polypropylene (PP) film applied to board surface. Matte PP: 20–30 GU gloss. Gloss PP: 70–80 GU. Provides water resistance and tear strength. Most common for rigid box wrapping.
- Soft-touch (suède) coating: Polyurethane-based coating with velvet feel. Gloss: 5–10 GU. Excellent tactile appeal. Cost adds $0.03–0.08 per sheet (A4 equivalent).
Recycled Content & Sustainability
Post-consumer recycled (PCR) content significantly affects paperboard properties. A 100% recycled board has 15–25% lower burst strength, 30–40% lower stiffness, and more variable caliper (±8% vs ±3% for virgin board) than virgin SBS. For gift packaging, a 30–50% PCR content is a common sustainability target that balances environmental claims with structural performance. FSC-certified virgin board is the premium alternative for eco-friendly positioning.
Moisture & Warp Considerations
Paperboard is hygroscopic — it absorbs moisture from the environment. At 50% RH, paperboard contains approximately 6–8% moisture by weight. At 80% RH, this rises to 10–12%. Excessive moisture causes warp, reduced stiffness, and poor print registration. For gift packaging, boards should be conditioned at 23°C, 50% RH for 24 hours before printing and converting. Moisture barrier coatings (aqueous or UV) reduce moisture absorption by 40–60%.
Relevant Standards
- FSC-STD-40-004: Chain of custody certification for FSC-certified paperboard
- ISO 536: Standard for grammage (GSM) testing
- EN 643: European standard for paper and paperboard grades
- CEN/TR 17219: Guidelines for recyclability of paper-based packaging