This standard specifies methods for testing water absorption when one side of non-absorbent paper and paperboard is in contact with water for a specified period of time.
JIS P 8140:1998 history
1998JIS P 8140:1998 Paper and board -- Determination of water absorptiveness -- Cobb method
1976JIS P 8140:1976 Testing method for water absorptiveness of paper and paperboard (cobb test)