Specifications for Lig-free Archival Papers
1. The paper should be made from fully bleached, alpha cellulose pulp. It should be free of lignin, ground wood, waxes, plasticizers, reducible sulfur, oxidizing chemicals and potentially harmful non-cellulose products. It should be free of particles of metal with a maximum 30 ppm Fe and .7ppm Cu. The board shall be hard sized with chemically saturated organic compounds to a Cobb size test of not more than 100 grams per square meter (TAPPI) T-441 (os-69). The surface of the paper should be smooth and free from knots, shives and abrasive particles.
2. pH range: The paper should have a pH of not less than 8.5 nor more than 10.2.
3. Sizing: Alkaline sizing should be used in place of alum-rosin sizing.
4. Alkaline reserve: The paper should contain a minimum of 3% calcium carbonate (CaCO3), or other suitable alkaline buffer.
(These strength specifications are for .010" thick paper.)
5. Abrasion test: The paper shall show maximum fiber loss of one-tenth of one percent after 100 cycles according to TAPPI 476.
6. Smoothness test: The paper should show a minimum smoothness of 195 Sheffield units following TAPPI UM-518 test.
7. Folding endurance test: The paper should withstand a minimum of 1,000 double folds in the weakest direction at 1kg. load after conditioning according to TAPPI T 511.
8. Internal tear resistance (Elmendorf): The paper shall have a minimum tear resistance of 350 gr. per sheet after conditioning TAPPI T414.
9. Stiffness test: The paper should have 2800 stiffness units in the machine direction and 1400 stiffness units in the cross direction in accordance with TAPPI 489.
10. Bursting strength: The paper should have a bursting strength of 300 pounds per square inch when tested in accordance with TAPPI T 807.
(This part pertains to those papers which are colored [dyed] such as our Lig-free , Type I.)
11. Color UNLESS otherwise specified the outer surface of the paper should be natural tan dyed with light-fast and non-bleeding dye.
12. Fading test: When the paper is exposed in a standard fadeometer TAPPI UM-461 for 30 hours, the difference in brightness TAPPI T 452, measured on the exposed and unexposed portions of the sample shall be less than 5 points.