Water absorbtion of raw paper is determined with the Cobb Test. Standards for this test are ISO 535, EN 20535 and TAPPI T 441.
The principle is:
- The dry specimen is weighed
- The specimen is placed under a cylinder with an inner diameter of 100 cm². Specimen and cylinder lie on a rubber and a steel plate
- Approx. 100 ml water is poured into the cylinder
- After a specified waiting time, the water is poured out. Excess water is removed from the specimen with blotting paper and roller.
- The specimen is weighed while wet and the amount of water is calculated that 1 m² of specimen material would absorb.
The advantages:
- Operator friendly instrument with quick clamping
- Also available for corrugated board
