ISO 5637:2024

Overview

ISO 5637:2024 - "Paper and board - Determination of water absorption after immersion in water" specifies a standardized laboratory method to measure how much water paper and board absorb when totally immersed for a defined period. The method applies to papers and boards that have some degree of water resistance (it is not intended for very absorbent products such as tissues). Results are reported as water absorption (g/m²) and relative water absorption (percentage mass increase) based on precise mass measurements taken before and after immersion.

Key Topics and Requirements

• Scope: Total immersion test for paper and board with water resistance; excludes very absorbent tissue products.
• Sampling & conditioning: Samples should be representative (ISO 186) and conditioned in a standard atmosphere (ISO 187) throughout the test.
• Test pieces: Standard size 200 mm × 250 mm (longer side in machine direction); prepare enough specimens to obtain 10 valid results.
• Apparatus & materials:
  • Precision balance (readability to 1 mg)
  • Soak tank maintained per ISO 187 and free from surfactants
  • Metal roller (approx. 200 mm wide, ~10 kg mass) for excess-water removal
  • Blotting paper (≈250 g/m² grammage) larger than the test piece
  • Tared containers and thermometer (±0.1 °C)
  • Water complying with ISO 14487 (deionized/distilled) at laboratory conditioning temperature
• Immersion times: Select by expected water resistance:
  • Low resistance: 5 min ± 5 s
  • Medium: 30 min ± 1 min
  • High: 24 h ± 15 min
    Alternative immersion times may be used if justified and documented to achieve complete saturation.
• Procedure highlights: Immerse pieces vertically, ensure separation and no trapped air, blot and roll once forward and backward without applied pressure, weigh immediately after blotting. Maintain consistent blotting/weighing timing.
• Calculations: Water uptake is computed from the mass difference before and after immersion and expressed per unit area (g/m²) or as a relative percentage increase in mass.

Applications and Users

ISO 5637:2024 is used by:

• Paper and board manufacturers for product development and quality control
• Packaging engineers assessing water resistance of corrugated and other boards
• Third-party testing and certification laboratories
• Converters and printers checking substrate behavior during wet-process handling
• R&D teams evaluating coatings, additives, and barrier treatments

Practical uses include validating water-resistant grades, comparing treatments or coatings, and specifying performance for packaging exposed to wet environments.

Related Standards

• ISO 186 - Sampling to determine average quality
• ISO 187 - Standard atmosphere for conditioning and testing
• ISO 14487 - Standard water for physical testing

Keywords: ISO 5637:2024, water absorption test, paper and board testing, immersion test, water resistance, paper testing standard.