ISO 5263-2:2004

Overview

ISO 5263-2:2004 - "Pulps - Laboratory wet disintegration - Part 2: Disintegration of mechanical pulps at 20 °C" specifies equipment and procedures for reproducible wet disintegration of mechanical pulps (mechanical, semi‑chemical and chemo‑mechanical pulps) that do not exhibit latency or where latency has been removed. The method is intended for preparing test portions used in other pulp test standards and for pulps measured for brightness. It is not suitable for pulps exhibiting latency (see ISO 5263‑3).

Key topics and requirements

• Test portion: take a sample equivalent to (50 ± 5) g oven‑dry pulp; avoid cutting sheet edges.
• Dry matter and concentration: determine dry matter by ISO 638 (wet/air‑dry) or ISO 4119 (slush).
• Soaking times (recommended):
  • < 20% dry matter: 0 min
  • 20–60%: 30 min

  • 60%: 4 h
    (Do not soak longer than 24 h; flash‑dried pulp needs ≥10 min.)

• Disintegration conditions: use water at (20 ± 5) °C (use ISO 14487 standard water where required). Add water to obtain (2 500 ± 25) ml in the disintegrator.
• Number of revolutions: the standard gives recommended revolution counts for different dry matter contents (see Table 2 of ISO 5263‑2); the counter can be pre‑set to switch off after the specified number. Visually confirm complete fibre separation and continue if necessary.
• Standard disintegrator: Annex A specifies construction and detailed dimensions (container, spiral baffles, three‑bladed propeller, clearances). Propeller rotational frequency is specified as (49 ± 1.5) s‑1. Annex B describes routine checks (shaft alignment, speed, blade geometry and condition).
• Reporting: test reports must reference ISO 5263‑2 and include sample ID, water grade, soaking time, dry matter, any deviations or unusual observations.

Applications and users

• Laboratories preparing pulp samples for routine physical and optical testing (e.g., brightness measurement).
• Pulp and paper mill quality control teams standardizing lab preparation of mechanical pulps and recovered fibres.
• Test houses, standards bodies and equipment manufacturers producing or verifying standard disintegrators.
• Useful where reproducible fibre separation is required prior to drainability, freeness or optical tests.

Related standards

• ISO 5263‑1 (chemical pulps) and ISO 5263‑3 (mechanical pulps with latency) - complementary parts of the ISO 5263 series.
• ISO 638 (dry matter), ISO 4119 (stock concentration) and ISO 14487 (standard water) - referenced normative documents.

Keywords: ISO 5263‑2, laboratory wet disintegration, mechanical pulps, standard disintegrator, pulp testing, brightness measurement, latency, standard water.