ASTM D919-97(2002) (R1997)

1.1 This test method (1, 2, 3, and 4) covers the determination of the copper number of bleached and purified paper and paperboard, except those containing calcium sulfite, zinc sulfide, melamine resin, urea-formaldehyde resin, starch, rosin size, or other copper-reducing nonfibrous materials. Paper containing such additives can be tested only if the amount and reducing power of the added material is known.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

The copper number can be regarded as an index of those impurities in cellulose such as oxycellulose, hydrocellulose, lignin, and sugars which possess reducing properties. It is valuable for detecting changes accompanying deterioration and may, therefore, be considered as a test for indicating the permanence of paper. In parchment and grease-proof papers, copper number is considered to give an indication of the degree of parchmentizing.