Overview
ISO 5637:1989 is an international standard established by the International Organization for Standardization (ISO) that specifies a method for determining the water absorption of paper and board after immersion in water. This standard applies to all types of paper and board that possess a degree of water resistance but excludes highly absorbent papers like toilet tissue. The method provides a reliable way to measure how much water is absorbed by paper materials after being submerged for a prescribed period, ensuring quality control and performance evaluation for water-resistant paper products.
Key Topics
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Scope and Applicability
ISO 5637:1989 applies to paper and board with water resistance properties and is not suitable for highly absorbent paper grades. It covers samples that can maintain their structural integrity after immersion.
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Test Principle
The procedure involves weighing paper samples before and after immersion in distilled or deionized water at 23°C ± 1°C. Water absorption is calculated based on the increase in mass per unit surface area or as a percentage increase relative to the original mass.
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Sample Preparation and Conditioning
Samples, or test specimens, should be cut precisely (usually 200 mm × 250 mm) aligned with the machine direction, conditioned according to ISO 187, and representatively sampled following ISO 186 for quality assurance.
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Testing Equipment
Required apparatus includes:
- A precision balance accurate to 0.01 g
- A water reservoir large enough to hold at least 10 vertically suspended samples without contact with the bottom or sides
- Supports such as wire frames with clips to prevent sample folding during immersion
- Pre-weighed containers for sample handling
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Immersion Duration
The immersion time depends on the water resistance level of the paper:
- Low resistance: 5 minutes ± 5 seconds
- Medium resistance: 30 minutes ± 1 minute
- High resistance: 24 hours ± 15 minutes
The goal is to reach complete sample saturation without over-immersion.
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Calculation of Results
- Water absorption is expressed in grams per square meter (g/m²).
- Water absorption rate is expressed as a percentage increase in sample mass.
Calculations follow specific formulas outlined in the standard, ensuring consistent and comparable results.
Applications
ISO 5637:1989 is critical for industries and laboratories focused on materials quality and performance involving paper and board products requiring water resistance, such as:
- Packaging industry - ensuring containers and cartons maintain strength under moist conditions
- Printing and publishing - assessing the durability of coated papers and boards
- Paper manufacturing - quality control and development of water-resistant paper types
- Research and development - evaluating new treatments or coatings that enhance water repellence
By quantifying water absorption, stakeholders can make informed decisions about material suitability, durability, and lifespan in environments where moisture exposure is a concern.
Related Standards
- ISO 186:1985 - Specifies methods for sampling paper and board to ensure representative quality testing.
- ISO 187:1977 - Defines conditioning parameters for paper and board samples before testing.
- ISO 769:1972 - Describes water absorption testing for fiberboards, analogous in method to ISO 5637 but designed for board materials.
These complementary standards provide a complete framework for analyzing paper and board properties, ensuring consistent testing conditions and meaningful interpretation of results.
Keywords: ISO 5637, water absorption, paper testing, board testing, water resistance, immersion test, paper quality control, water absorption rate, paper and board standards
