ISO 5269-3:2008

Overview

ISO 5269-3:2008, titled Pulps - Preparation of laboratory sheets for physical testing - Part 3: Conventional and Rapid-Köthen sheet formers using a closed water system, is an international standard developed by ISO. It specifies two procedures for preparing laboratory sheets from pulps with a high fines content using a closed water system in retention equilibrium. This standard addresses a critical need for reliable laboratory sheet preparation methods, especially for pulps where retention of fines is poor with open water systems. It applies primarily to mechanical, chemimechanical, and recycled fiber pulps, which contain a high levels of fines. The standard ensures reproducible conditions and improved accuracy for physical testing of such pulps.

Key Topics

• Closed Water System Preparation
  ISO 5269-3 outlines two separate procedures to establish a closed water circuit with retention equilibrium to prevent the loss of fines during laboratory sheet formation. This closed system minimizes fines loss compared to open water systems described in ISO 5269-1 and ISO 5269-2.

• Applicable Sheet Formers
  The standard provides specific methods for:

  • Conventional sheet former: Involving a water circulation system beneath and above the forming wire.
  • Rapid-Köthen sheet former: Using a reservoir with circulating water pumped above the wire for sheet formation.

• Retention Equilibrium
  Sheets prepared prior to achieving retention equilibrium are discarded. The process involves producing successive sheets until the dry mass of sheets stabilizes, indicating equilibrium of fines retention has been reached in the closed water system.

• Pulps Covered
  Focus is on pulps with high fines content such as:

  • Mechanical and chemimechanical pulps
  • Pulps from recycled fibers
    It is not intended for some very long-fibred pulps (e.g., unshortened cotton, flax) or primarily chemical pulps, which follow ISO 5269-1 or ISO 5269-2.

• Preparation Process
  After establishing equilibrium, laboratory sheets for physical testing are prepared following the relevant procedures in ISO 5269-1 (conventional) or ISO 5269-2 (Rapid-Köthen).

• Exclusions
  The method is not applicable for preparing laboratory sheets to measure ISO brightness, for which ISO 3688 applies.

Applications

• Physical Testing of Pulps
  Facilitates consistent preparation of laboratory sheets that accurately reflect the physical properties of pulps with high fines content. This is crucial for evaluating pulp quality, performance, and suitability for paper production.

• Pulp and Paper Industry Research and Quality Control
  Useful for research labs and manufacturing quality control to monitor and optimize pulp characteristics, especially when using recycled fibers or mechanical pulps where fines retention is a concern.

• Standardized Testing Environments
  Supports reproducibility in comparative studies and regulatory compliance by standardizing sheet formation techniques, water circulation, and conditioning prior to physical testing.

• Analytical Procedures
  Ensures that sheets prepared under controlled closed water circulation systems are representative, enhancing reliability of test data (e.g., strength, bonding, porosity).

Related Standards

• ISO 5269-1:2005
  Methods for preparation of laboratory sheets using the conventional sheet former with an open water system.

• ISO 5269-2:2004
  Methods for preparation of laboratory sheets using the Rapid-Köthen sheet former with an open water system.

• ISO 5263 Series
  Related to wet disintegration of different pulp types prior to sheet preparation:

  • ISO 5263-1 (chemical pulps)
  • ISO 5263-2 and ISO 5263-3 (mechanical pulps)

• ISO 3688
  Specifies preparation of sheets for measuring ISO brightness, not covered by ISO 5269-3.

• ISO 187
  Conditioning of laboratory sheets prior to physical testing.

• ISO 5270
  Guidelines for physical testing of sheets prepared by these methods.

Practical Benefits

• Enhanced Accuracy for High-Fines Pulps
  Closed water systems minimize fines loss, providing sheets that better represent actual pulp composition for reliable test results.

• Adaptability to Different Sheet Formers
  Clear procedures for both conventional and Rapid-Köthen equipment maximize utility across various laboratory setups.

• Improved Quality Control
  Enables standardized preparation that supports consistent monitoring of pulp performance, aiding industry decisions on pulp processing and product development.

• Supports Sustainable Practices
  By addressing pulps from recycled fibers, the standard promotes sustainable paper production practices with accurate assessment methods.

ISO 5269-3:2008 remains a key international standard for the pulp and paper industry, guiding laboratory practices to prepare representative sheets that reliably reflect the physical properties of high-fines pulps using closed water systems with conventional and Rapid-Köthen sheet formers.