Overview
The PN-COBB Cobb Absorbency Tester is a paper and Cardboard Water Absorbency testing instrument developed by PNSHAR brand according to the national standard GB/T 1540. It is suitable for measuring the Water Absorbency (Cobb value) on the surface of sizing paper and Cardboard, that is, under certain conditions, the mass of water absorbed by the unit area of paper and Cardboard within a specified time. The instrument adopts the Cobb (Cobb) test method and is not suitable for base paper and embossed paper with Basis Weight less than 50g/m ², low sizing degree or more pinholing, nor for unglued paper and Cardboard and accurate evaluation of writing performance.
Features
1. Developed according to the national standard GB/T 1540, in line with relevant standards.
2. The classical Cobb (Cobb) test method was used to determine the Water Absorbency on the paper surface.
3. Provide standardized test area and water consumption to ensure test accuracy.
4. The roller parameters are accurate and meet the length and mass requirements specified in the standard.
Principle
The instrument works based on the principle of Cobb (Cobb) test method. Under specified conditions, a certain amount of water is contacted with the surface of the sample and maintained for a specific time (e.g. 30 seconds, 60 seconds, etc.). After reaching the specified time, the remaining water that has not been absorbed is removed, and the mass of the absorbed water per unit area is calculated by measuring the change of the mass of the sample before and after water absorption, that is, the Cobb value is obtained, expressed in grams per square meter (g/m ²).
Applications
Determination of Surface Water Absorbency of Sizing Paper and Cardboard
Standards
GB/T1540、QB/T1668、ISO535、TAPPI T441
Steps
1. Prepare paper or Cardboard samples that meet the requirements.
Place the specimen in the instrument test area to ensure that the test area is (100 +/- 0.2) cm ².
3. Add the specified amount of water (100 +/- 5ml) to the surface of the sample.
4. Select and start timing according to the standard (e.g. 30s, 60s, etc.).
After reaching the specified water absorption time, remove the remaining water according to the specified time (for example, the 30s test needs to remove the water within 20 +/- 1s).
6. Immediately weigh the mass of the sample after absorbing water.
7. Calculate the water absorption per unit area and obtain the Cobb value.
Notice
• This instrument is not suitable for papers with Basis Weight less than 50g/m ².
• Not suitable for base paper and embossed paper with low sizing or more pinholing.
• Not suitable for unglued paper and Cardboard.
• Not suitable for accurately evaluating the writing performance of paper or Cardboard.
• It is necessary to operate in strict accordance with the test time specified in the standard (including the time for absorbing water and removing the remaining water).
• Ensure that the test water consumption and roller parameters meet the specifications.
