ASTM D3521 Standard Test Method for Surface Wax Coating On Corrugated Board
8. Procedure
8.1 Take each duplicate specimen and separate the coated facing from the combined board as follows:
8.1.1 Delaminate the fibers of the facing in a manner that causes minimum disturbance of the surface coating and produces a thin continuous paper sheet. To do this, pry with a fingernail or blade at the corner of the specimen to start separating the fibers within the facing itself, then pull to delaminate, maintaining a low angle and a diagonal direction. Mark the reverse side to identify the specimen number. Weigh the duplicate delaminated pieces together before scraping and record the weight to the nearest 1 mg.
NOTE 4 - For some types of combined board, the surface is smooth and free of ridges. In such cases, delamination of the liner may not be necessary.
8.2 Remove the surface wax from the surface of each delaminated piece by scraping the wax in four separate operations as follows:
8.2.1 Place the delaminated piece on a smooth hard surface such as a glass plate. Using a fresh razor blade for each test (100 cm2 total), begin scraping in the direction parallel to the flutes as seen by the residual impressions. Hold the blade so that it is drawn toward the operator and is held close to the vertical. Place the blade so that it covers the width of the first flute. Use a moderately firm stroke and completely traverse the section of the specimen on one steady motion. It is important to do thorough scraping to ensure that there is no surface film of wax remaining. In removing the wax film it is acceptable to also remove a minor amount of paper fibers, but avoid excessive removal of fibers (see Note 5). After the first stroke, move the blade to cover an additional portion of the specimen about the width of the next flute impression and repeat the scraping stroke. Proceed across the specimen discarding the wax scrapings but preserving the integrity of the paper sheet.
NOTE 5 - The minor amount of fibers removed with the wax scrapings may be ignored; this error tends to cancel the error of incomplete scraping. Tests indicate that with normal surface scraping the fibers scraped off should constitute only about 5 % of the weight of the scrapings.
8.2.2 After completing the uniform scraping in one direction, then turn the specimen by 90° and repeat the progressive scraping. Continue turning and scraping through the next 90° and the last 90° to complete the full rotation. Finally, inspect the specimen carefully to detect any areas with remaining surface wax and re-scrape such areas.
8.2.3 Carry out the same procedure with the duplicate facing specimen. Weigh the scraped specimens together and record the weight loss to the nearest 1 mg.
9. Calculation
9.1 Calculate the weight of surface coating on the facing, a, in g/m2, as follows:
a = (c - d)/b
where:
b = specimen area, total, m2,
c = weight of duplicate delaminated facings, before scraping, g, and
d = weight of facings, after scraping, g.
