| 摘要 |
<p>Cardboard is waterproofed by applying a surface coating of polyester resin to be cured in situ. The process is esp. for treating single or double walled corrugated cardboard for making packaging or for non-stick trays or drawers for holding photographs or documents, where resistance to excessive absorption or loss of moisture is required. The polyester coating is lighter than Al foil, more heat resistant than wax coatings, and less prone than either to delamination. The coating increases the strength of the structure. Porous card structures may be partially sealed with e.g. a cellulose- or starch-based size before the polyester resin is applied. The coating may be applied to one or both faces of the card by spray, brush, roller from solution or suspension as appropriate, may be heat or catalytically cured.</p> |
