This machine is a conventional instrument for the water absorption test of paper and cardboard surface, also known as paper surface absorption gravimetric Tester. This instrument uses the Cobb test method, which is one of the many methods of absorption testing, so it is also called the erection Tester. It is mainly used to determine the surface water absorption of sizing paper and cardboard, including corrugated cardboard. This instrument only measures the water absorption of paper and cardboard surfaces, but is not suitable for accurately evaluating the writing properties of paper or cardboard.
Definition of surface water absorption (Cobb) value of paper and cardboard: the amount of water absorbed by the surface of paper and cardboard per unit area under a certain pressure and temperature within a specified time, measured in g/㎡. The specific formula is as follows: C=(G2-G1)×100.
where:C —— erection water absorption value;G2 —— The mass of the specimen weighed after water absorption;G1 —— The quality of the specimen weighed before water absorption.
Note: The contact part between the cylinder torus and the sample should be smooth, and when the quantitative amount of a single layer of absorbent paper is less than 200~250 g/㎡, multiple layers can be superimposed to meet the requirements.
ISO535—1991 Determination of water absorption of paper and cardboard – Cobb method
GB/T1540—1989 Determination of water absorption of paper and cardboard (Kebo method)