Testing Services for the paper, nonwovens, packaging, and consumer products industries.

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TAPPI T 441 Cobb Test




TAPPI T 441 Cobb Test


Water absorptiveness of sized (non-bibulous) paper, paperboard, and corrugated
fiberboard (Cobb test)


TAPPI T 441 Cobb Test describes a procedure for determining the quantity of water absorbed by nonbibulous paper, paperboard, and corrugated fiberboard in a specified time under standardized conditions. It is based on studies by Cobb and Lowe, Cobb and other investigators. For testing unsized and absorbent paper or paperboard, see TAPPI T 432 “Water Absorbency of Bibulous Paper.”


Water absorptiveness is a function of various characteristics of paper or board such as sizing, porosity, etc. This method is generally applicable to sized paper, paperboard and corrugated fiberboard, but it is not recommended as a sizing test for writing paper.


To perform adequate testing five, 8.5″ x 11″ sheets are requested. Five replicates for both the felt and wire side of the paper are tested. If sample quantity is limited, testing can be done by sampling fewer sheets and/or performing fewer replicates. If additional TAPPI test methods are requested, ten sheets may be required to perform all  testing.

IPS does a short test for 120 seconds for paper or a long test for 30 minutes for combined board. If the material fails the standard test, the customer will be contacted to discuss optional test parameters and costs. If requested by the customer different test periods can be used.

Please note:

IPS cannot sell or otherwise provide standards, specifications, or test procedures to third parties.