Overview
ISO 5263-3:2023 - Pulps - Laboratory wet disintegration - Part 3: Disintegration of mechanical pulps at ≥85°C specifies the apparatus and procedures for laboratory hot wet disintegration of mechanical pulps that exhibit latency. Applicable to mechanical, semi-chemical and chemi‑mechanical pulps, this standard defines how to remove latency by combining mechanical treatment and heat (≥85 °C) so pulps can be prepared reproducibly for downstream tests (e.g., freeness, strength). The procedure can also be used to prepare test portions for other International Standards.
Key technical topics and requirements
- Scope: Applies to mechanical pulps exhibiting latency (except when brightness is measured - see ISO 5263-2 for brightness).
- Temperature: Maintain the fibre–water suspension at ≥85 °C during disintegration.
- Disintegrator types: Use either the standard disintegrator (Annex A) or the circulation (Domtar) disintegrator (Annex C). Report which type was used because treatment differs.
- Test portion mass:
- Standard disintegrator: (50 ± 5) g oven-dry pulp
- Circulation disintegrator: (56 ± 1) g oven-dry pulp
- Soaking time (Table 1):
- Dry matter < 20%: 0 min
- 20–60%: 30 min
-
60%: 4 h (flash-dried: minimum 10 min)
- Standard disintegration cycle: heat to ≥85 °C, run propeller for 30 000 revolutions (visual check for complete separation).
- Circulation disintegration: preheat system with 90–95 °C water, run pump cycles of (120 ± 5) s; ensure fibre separation and a final temperature ≥85 °C.
- Immediate cooling/dilution: after hot disintegration dilute rapidly to 0.3–1.5% concentration at (20 ± 2) °C (or (0.30 ± 0.02)% for freeness testing) to avoid re-establishment of latency.
- Reporting requirements: include reference to ISO 5263-3:2023, sample ID, water grade (ISO 14487), soaking time, dry matter (ISO 638-1 / ISO 4119), disintegrator type, any deviations.
Practical applications and users
- Quality control and R&D laboratories in pulp and paper mills
- Independent testing labs performing freeness, drainage, fiber morphology or strength tests
- Instrument manufacturers (disintegrators) and method developers
- Standards committees and auditors verifying test preparation consistency
ISO 5263-3:2023 ensures reproducible latent‑property removal for mechanical pulps, enabling reliable comparison of pulp properties and consistent preparation of test portions across labs.
Related standards
Keywords: ISO 5263-3:2023, pulps, laboratory wet disintegration, mechanical pulps, latency removal, standard disintegrator, circulation disintegrator, hot disintegration, freeness testing.
Open preview (PDF)Pulps — Laboratory wet disintegration — Part 3: Disintegration of mechanical pulps at ≥85°C