What does Water Absorbency of Paper means?
Water absorbency or sizing adequacy is a measurement of the amount of water which is absorbed by the wetted surface of the paper and paperboard materials. Various test methods have been introduced to measure the water absorbency strength of the papers, paperboards, cardboards and related materials. One of the popular test methods which are used to measure the water locking strength or water resistance strength of the cardboards and paperboards is Cobb Sizing Test. Using cobb sizing test, water absorbent rate of papers, boards, and related products.
Cobb Test for Papers & Paperboards
A cobb test is a highly effective test method which is used to determine the water absorption strength of the papers and the sizing adequacy of the materials according to which a paper sample can be weighed and placed in a tight cylindrical vessel which is backed with a rubber gasket on a metal ring which ensures zero percent leakage.
To perform the test, the cylindrical ring is filled with water by exposing the upper side of the sample to water. After a set period of time, the water is drained, and the remaining water is blotted off from the surface of the paper using a roller provided with the machine by moving the roller on the sample one time in forward direction and one time in backward direction without exerting pressure on it. After the procedure, the same is weighed again. The weight gained by the sample after soaking a specific amount of water is considered as the water absorbency of material.
How does Cobb Test help in Quality Determination?
The Cobb Sizing Test of papers helps to measure the amount of water that a non-bibulous paper, corrugated board, paperboard, size paper or related materials can absorb or resist in a set period of time say 60 seconds. This test helps to measure the absorbency of the materials and measured in unit g/m2. Water absorbency of a material strongly influences the printability of water based adhesives.
Presto Stantest, one of the leading manufacturer, supplier, and exporter of testing machines, offers a wide range of paper and packaging testing machines. One such testing device which is used to measure the strength of papers is Cobb Sizing Tester. The testing machine is used to perform the Cobb test easily and helps to determine the water absorption strength of papers. The instrument is designed in strict conformance with the standard TAPPI T441 and ASTM D 3285. For more information on Cobb Sizing Tester, contact our experts.