Yes. In the Chinese paperboard market, two materials with the same or similar GSM can have different fibre composition, density, bulk, thickness and bending stiffness. A quotation that states only “300gsm white card” does not give an overseas buyer enough information to predict the finished box performance.

GSM measures the weight of one square metre of paperboard. It does not directly specify caliper, density or finished-box stiffness. A dense board and a bulky board can carry the same GSM while folding, resisting pressure and protecting a cake very differently. For this reason, UGI Packging recommends approving both GSM and measured thickness.

Based on UGI Packging sourcing and production experience in the Chinese paperboard market, food-grade white paperboard commonly provides about 10%–15% higher stiffness than regular white card of the same GSM. The actual result depends on the mill, fibre structure, grain direction, moisture, coating and box design, so the approved sample remains the final production reference.

In a typical 6-inch cake box structure, UGI Packging has found that a 300gsm food-grade board can achieve approximately the same structural performance as a 350gsm regular white card. This can reduce the material weight without reducing the required box strength. It should be treated as a project example rather than an automatic substitution for every cake box.

Specify the paperboard grade, GSM and actual caliper in millimetres or microns. Caliper is the most practical safeguard against receiving a thinner or denser board under the same GSM description. The purchase specification should also state the permitted thickness tolerance, grain direction and approved physical sample.

For China-market purchasing, a target caliper tolerance of approximately ±5% is a practical starting point unless a tighter mill specification has been agreed. The tolerance should be written into the quotation, sample approval and purchase order. Published mill data may use tighter tolerances, but buyers should not assume those limits apply to every Chinese white-card grade.

Published technical data supports the principle that GSM does not uniquely determine thickness. For example, two published 315gsm folding boxboards in the same international mill portfolio are specified at 600μm and 555μm respectively—a 45μm difference at the same GSM. These figures are reference benchmarks, not a one-to-one comparison of Chinese food-grade and regular white card.

Ask for the supplier technical data sheet and a physical sample, then record the approved GSM and measured caliper. Measurements should be taken at multiple positions away from creases, print buildup and laminated edges. The approved production sample should be retained so incoming material and finished boxes can be compared against it.

Not automatically. The selected paperboard, coating, ink, adhesive and intended use must be considered together. For direct food-contact projects, UGI Packging can specify OBA-free food-grade board and provide the available supplier declarations or SGS/FDA-related supporting documents for the exact material selected. Buyers should approve the documents for their destination market and application.

Include the board type, GSM, target caliper, maximum thickness tolerance, grain direction, box dimensions, product weight, required stiffness or approved comparison sample, OBA requirement, direct or indirect food contact, printing and coating details, quantity and destination market. A specification written this way is much safer than requesting only “300gsm food-grade white card.”