Overview
ISO 105‑Z04:1995 - titled "Textiles - Tests for colour fastness - Part Z04: Dispersibility of disperse dyes" (document extract shown as ISO 105‑204:1995) specifies a laboratory method to evaluate the dispersibility of disperse dyes in aqueous media. The procedure quantifies dispersibility using two measurable outputs: filtration (filtering) time and filter residue. The test is intended to assess how well dye powders disperse under defined conditions - a critical attribute for reproducible dyeing of polyester and other hydrophobic fibres.
Key topics and technical requirements
- Scope: Determines degree of dispersion in aqueous media only; strict adherence to test conditions is required for reproducible results.
- Principle: Disperse dye is dispersed, heated (typically 70 °C ±2 °C for 5 min) or optionally dispersed at 25 °C, then vacuum‑filtered through a reference filter. Measure time to initial wetting and evaluate retained residue.
- Test variants: Three variants selected by application:
- Test I - for critical dispersion (e.g., package polyester dyeing)
- Test II - for high bath‑ratio dyeing (liquid baths)
- Test III - for polyamide dyeing (carpets, apparel)
- pH conditions:
- Tests I & II: pH 4.5–5.0 (acetic acid)
- Test III: pH 9.0–10.0 (TSPP)
- Apparatus & materials: Büchner funnel (110 mm), specified filter papers (Quality A retains >8 µm, Quality B >25 µm), stainless ring dimensions, vacuum system (3–4 kPa), analytical balance, magnetic stirrer, ISO 3696 grade 3 water, reagents (TSPP, acetic acid, optional EDTA/NTA).
- Classification:
- Filtration time classes: A (0–24 s), B (25–49 s), C (50–74 s), D (75–120 s), E (≥120 s).
- Filter residue classes: 5 (excellent) to 1 (poor); coarse particles automatically classify as 1.
- Reporting: Include standard reference, sample description, chosen test number, whether 25 °C variant used, filtration‑time class and residue class (example format: I‑A‑3).
Practical applications and users
- Who uses it: dye manufacturers, textile chemists, quality control laboratories, textile mills, and contract testing labs.
- Why it matters: Ensures consistent dispersion quality for disperse dyes - critical for uniform dye uptake, minimization of specking and defects in polyester and blended textiles, and to guide formulation and process controls.
- Use cases: Incoming dye quality control, batch comparison, troubleshooting dyeing defects, and specification of dye grades for specific dyeing methods (package vs bath dyeing).
Related standards
- ISO 3696 - Water for laboratory use (quality 3) - referenced for water quality.
- ISO 105 series (including ISO 105‑A01) - general principles and related colour fastness test procedures.
Keywords: ISO 105‑Z04:1995, dispersibility of disperse dyes, disperse dyes dispersibility test, filtering time, filter residue, textile dye testing, colour fastness tests.