paper making pencil stone standard

SUPER class1 class2
thin 325item----400item
white≥ 90° 85° 80°
wet≤ 0.5°
atomy
gram/mm≤ 0.4 0.6 0.6
calcium carbonate%≤ 2.5 3.0 3.0
burn lost %≤ 6.0 8.0 10
PH 7-----9