SURFACE WAX COATING ON CORRUGATED BOARD: ASTM D3521
EXPLANATION
Wax coatings are applied to corrugated board to provide a better barrier against moisture or other agents or to provide improved appearance or abrasion resistance. These performance features are influenced by the amount of wax present on the surface. During most coating operations, the major portion of the wax applied will congeal on the surface, while a minor proportion will migrate into and become embedded in the fibers of the facing. This method measures only the portion on the surface. This method is applicable to board to which wax has been applied by curtain coating, roll coating, or other methods; the substrate board may or may not contain impregnating (saturating) wax within its structure. If it is known that the specimen has coating wax only, with no internal saturating wax, the total coating wax applied may be determined by Test Method ASTM D3344.
TEST SUMMARY
The amount of wax present as a coating on the surface is determined by delaminating the coated facing to obtain a ripple-free sheet, then scrapping off the wax using a razor blade, and calculating the wax removed.
TEST PRECISION
Repeatability: 15 % of the mean
Reproducibility: 24 % of the mean
Due to the high degree of normal variability from specimen to specimen, close precision may be difficult to obtain. In cases where close precision is needed or precision is suspect, multiple sampling and testing should be done.
This procedure has no bias because the value of the surface wax can be defined only in terms of this test method.
