ASTM D3708 Standard Test Method for Weight of Wax Applied During Curtain Coating Operation
4. Summary of Test Method
4.1 The amount of wax applied to corrugated board by means of a curtain coater is determined by attaching a folded sheet of paper to production corrugated board, running the combination through the curtain coater, and subsequently determining the applied weight of wax on the sheet of paper.
5. Significance and Use
5.1 Wax coatings are applied to corrugated board to provide a barrier against moisture or other penetrants or to provide improved appearance or abrasion resistance. These functional properties are influenced by the amount of wax present on the surface.
5.2 During curtain coating operations, major portions of the wax will congeal on the surface, while a minor portion will penetrate and become embedded in the fibers of the facing. This method measures the total weight of wax applied to the board. The amount actually remaining on the surface of the corrugated board can be determined by Test Method D3521.
5.3 The uniformity of application of wax film across the width of the curtain coater may also be determined using this technique by passing test combinations (blanks) under the curtain at various locations, that is, left side, center, right side.
