Overview
ISO 4576:1996 specifies a standardized laboratory method for determining sieve residue (gross particle and coagulum content) in aqueous polymer dispersions. The standard addresses only coagulum-type particles - particles much larger (for example 10× or 100×) than the mean particle diameter - and defines a sieve-analysis procedure to quantify their mass fraction in a dispersion.
Key topics and technical requirements
- Scope: Measurement of coagulum (gross particles) in polymer dispersions using sieving; excludes skin fragments > 5 mm when sampling.
- Sampling: Follow ISO 123 or ISO 842 sampling procedures to obtain a homogeneous test portion.
- Test portion: Typically 100–200 g (larger portions up to 1 000 g may be used).
- Dilution: Dilute with deionized water (volume equal to twice the test portion mass, in mL) and add a stabilizing surfactant if needed.
- Sieves: Use metal (preferably stainless steel) gauzes per ISO 3310-1; common mesh aperture sizes listed include 45 μm, 63 μm, 90 μm, 125 μm, 180 μm. Non-metallic gauzes are permitted if declared.
- Apparatus: Filtration assembly, sieve supports, ovens (preferred drying temperature 105 °C ±2 °C; alternatives 80 °C, 125 °C or 140 °C depending on polymer stability), desiccator, analytical balances (accuracy 1 mg for ≤200 g samples; 0.1 mg for sieve + residue).
- Procedure (high level): Pour diluted dispersion onto pre-weighed, dried sieve, wash residue to clear filtrate, dry to constant mass and weigh. Calculate residue (%) = (m2 − m1) × 100 / m0, where m0 = test portion mass, m1 = sieve mass, m2 = sieve + dried residue mass.
- Repeatability & acceptance: Perform two determinations; individual results must agree within ±5% of the mean. Estimated same-operator repeatability is ±8% for duplicate tests performed on the same day.
- Reporting: Include reference to ISO 4576, sample identification, sieve and drying temperature, residue percentage, residue description, any deviations, and test date/place.
Applications and users
ISO 4576 is used by:
- Quality control laboratories in paints, coatings and adhesives manufacturing
- Polymer and latex producers monitoring coagulum content
- Independent testing laboratories performing product specification checks
- R&D teams developing aqueous polymer dispersions
Benefits include consistent, comparable quantification of gross particles/coagulum to support product quality, batch acceptance, process control and supplier verification.
Related standards
Keywords: ISO 4576, polymer dispersions, sieve residue, coagulum content, sieve analysis, particle size testing, plastics testing, QC for dispersions.