Testing Standard:
TAPPI T441 Water Absorptiveness of Sized (Non-Bibulous) Paper, Paperboard, and Corrugated Fiberboard (Cobb Test)
Standard Number
TAPPI T441
Standard Title
Water Absorptiveness of Sized (Non-Bibulous) Paper, Paperboard, and Corrugated Fiberboard (Cobb Test), Test Method
Overview:
TAPPI T441 Test Method is used to evaluate the materials rate of water absorption and to verify the performance of any coatings and the sizing applied to the paper. Purple Diamond Testing offers TAPPI T441 Water Absorptiveness of Sized (Non-Bibulous) Paper, Paperboard, and Corrugated Fiberboard (Cobb Test) as part of our packaging compliance and validation services.
Rationale:
TAPPI T441 – Water Absorptiveness of Sized (Non-Bibulous) Paper, Paperboard, and Corrugated Fiberboard (Cobb Test). The amount of moisture in paper affects the overall physical strength, porosity, and printability. This method can be ideal when evaluating different surface coatings applied to the material for increased performance in addition to verification of resistance to water absorption requirements, which are common for some regulated packaging. Depending on the material, the test’s duration is between one and thirty minutes and measures the amount of water absorbed by weight.
Key Points:
- Determines the need for moisture barrier coatings and the sizing of paper
- Using this test method verifies compliance with UN DOT regulations
- Utilize this test method to ensure quality control
- Verifies the amount of surface coating used is sufficient
Related Standards:
- ASTM D3285 – Test Method for Water Absorptiveness of Non-Bibulous Paper and Paperboard (Cobb Test)
- ISO 535 – Paper and Board – Determination of Water Absorptiveness – Cobb Method
Related Testing Standards
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