Buying Guide
Grey Board and Paper Board Materials Guide
Product knowledge for grey board and paperboard used in rigid boxes and cartons: grades, thickness, flatness, moisture, sourcing specs, and buyer tests that prevent warp and weak structures.
Where grey board sits in packaging
Grey board (chipboard) is the structural core of most rigid gift boxes and many book-style or drawer packs. It is distinct from folding carton board (SBS/FBB/coated recycled board) and from corrugated board. Buyers who specify “cardboard” without naming the family get mismatched quotes and samples.
Thickness, density, and what they control
Thickness (mm) and density/GSM drive stiffness, weight, and cost. Larger lids and wide spans need thicker or denser board to resist bowing. Over-specifying thickness on small boxes wastes money and freight. Ask suppliers to state thickness tolerance and whether caliper is measured before or after conditioning.
Grade and surface quality
Boards vary in ply bonding, surface dusting, and flatness. Poor bonding delaminates when wrapped or die-cut. Dusty surfaces hurt glue and wrap adhesion. For premium wraps, request cleaner surfaces and tighter flatness. If the board face will be printed directly (less common for rigid cores), surface requirements rise further.
Moisture and warp—the silent defect
Grey board is hygroscopic. Humidity swings between factory, container, and destination warehouse cause warp and lid misalignment. Specify storage and packing (wrapped pallets, moisture barriers) and avoid extreme thickness mismatches between lid and base without design compensation. Flat samples can warp after ocean freight if packing is weak.
Recycled content and odor
Most grey board is recycled-fiber based. That supports some sustainability narratives but can introduce odor or inconsistency. Cosmetics, food-adjacent gifts, and fragrance brands should evaluate odor on sealed samples. Recycled-content claims need documentation aligned to your market—do not invent percentages from supplier marketing lines.
How grey board is bought in China programs
Rigid-box factories often source board from specialized mills. Ask whether your supplier buys fixed grades or shops spot lots. Spot shopping can lower price and raise variation. For ongoing SKUs, freeze mill/grade equivalents and require approval for substitutions. Traceability matters when a bulk lot warps and you need root cause.
Buyer tests and acceptance checks
Measure thickness at multiple points; check flatness on a true surface; flex corners for ply bond; wrap a small trial piece if adhesion is critical; condition samples similarly to expected logistics when possible. For finished boxes, lid gap and twist are often grey-board problems showing up late.
Interaction with wraps, glues, and magnets
Thick board needs adequate wrap turn-in allowances and glue open time. Magnets need correct cavity depth and board strength so closures do not crush. Soft-touch wraps can telegraph surface defects—board cleanliness matters more than buyers expect.
Specification fields to put on the RFQ/PO
Thickness + tolerance; density or GSM class if used; flatness expectation; recycled-content documentation if claimed; packing/moisture protection; approved mill/grade or equivalent; substitution rules. Tie board specs to the finished box drawing, not only to a marketing thickness name.
Related materials buyers often confuse
Folding carton boards for tuck-end cartons; corrugated for shippers; honeycomb or reinforced boards for heavy gift sets. Choose the family from structural need, then grade within family. See Gift Boxes and Rigid Packaging Buyer Guide for finished-box decisions that ride on these material choices.
Related PackTrades Knowledge
Gift Boxes and Rigid Packaging Buyer Guide, How to Evaluate Custom Packaging Suppliers in China, Sustainable Packaging Trends 2026.