Overview
EN ISO 5263-3:2023 - "Pulps - Laboratory wet disintegration - Part 3: Disintegration of mechanical pulps at ≥ 85 °C" is a CEN-endorsed ISO standard that specifies the apparatus and procedures for laboratory wet disintegration of mechanical pulps exhibiting latency (except when brightness is measured). The method is intended for preparing test portions used in other pulp and paper test standards and applies to all types of mechanical pulps (mechanical, semi‑chemical and chemi‑mechanical) that require latency removal at elevated temperature.
Key topics and technical requirements
- Scope & applicability: Applies to mechanical pulps exhibiting latency; brightness testing uses ISO 5263‑2 instead.
- Temperature requirement: Disintegration and latency removal are carried out at ≥ 85 °C. The standard explicitly requires reducing the suspension temperature immediately after disintegration.
- Disintegrator types:
- Standard disintegrator (Annex A) - may be electrically heated or supplied with hot water. Procedure for checking the standard disintegrator is provided (Annex B).
- Circulation disintegrator (Domtar type) (Annex C) - requires water supply at 90–95 °C and controlled pump operation.
- The disintegrator type used must be reported because they affect fibre treatment differently.
- Test portion and preparation:
- Standard disintegrator: test portion = (50 ± 5) g oven‑dry pulp.
- Circulation disintegrator: test portion = (56 ± 1) g oven‑dry pulp.
- Use standard water (ISO 14487), distilled or tap water as required by downstream tests.
- Soaking recommendations:
- < 20% dry matter - 0 min
- 20–60% - 30 min
-
60% - 4 h
- Flash‑dried pulp - minimum 10 min
- Safety: Procedures involve high temperatures (≥85 °C); appropriate safety precautions are required.
- Reporting: Test report shall include apparatus type, temperatures, soaking and disintegration conditions, and any deviations.
Applications and who uses this standard
- Pulp and paper laboratories performing quality control (QC), acceptance testing and inter-lab comparisons.
- Mill process control teams needing reproducible latency removal for mechanical pulp characterization.
- R&D groups evaluating fibre properties, drainage, strength and other pulp properties that depend on fully disintegrated samples.
- Standards bodies and test method developers using the disintegration procedure as a sample-preparation step for other standardized tests.
Related standards
- ISO 5263‑2 - Hot disintegration for brightness measurements (see note: brightness testing uses part 2).
- ISO 638‑1 - Determination of dry matter (oven-drying).
- ISO 4119 - Determination of stock concentration.
- ISO 14487 - Standard water for physical testing.
Keywords: EN ISO 5263-3:2023, laboratory wet disintegration, mechanical pulps, latency removal, disintegrator, ≥85°C, pulp testing, standard water.
