ISO 4576:2026

• Abstract:

  This document specifies a method of determination of the sieve residue (gross particle and coagulum content) of polymer dispersions. This document is only applicable to coagulum type content.

• Status: Published
• Publication Date: 12-Nov-2026
• ICS: 83.080.01 - Plastics in general
• Technical Committee: ISO/TC 61/SC 9 - Thermoplastic materials
• Drafting Committee: ISO/TC 61/SC 9/WG 14 - Polymer dispersions
• Current Stage: 6060 - International Standard published
• Start Date: 13-Nov-2026
• Completion Date: 13-Nov-2026

• Revises: ISO 4576:1996 - Plastics — Polymer dispersions — Determination of sieve residue (gross particle and coagulum content)
• Effective Date: 04-Nov-2023

ISO 4576, published by the International Organization for Standardization (ISO), specifies a test method for determining the sieve residue of polymer dispersions. The method is aimed at coagulum-type content - particles much larger than the mean particle size - so laboratories can measure gross particle and coagulum content in a dispersion.

What does ISO 4576 specify?

ISO 4576 specifies a filtration-and-weighing method for polymer dispersions, with the result reported as sieve residue by mass. The method is limited to coagulum-type content, so it is used when the question is how much coarse residue is present in a sample.

ISO 4576 is organized into these main clauses:

• Clause 1 Scope
• Clause 2 Normative references
• Clause 3 Terms and definitions
• Clause 4 Principle
• Clause 5 Reagents
• Clause 6 Apparatus
• Clause 7 Sampling
• Clause 8 Procedure
• Clause 9 Expression of results
• Clause 10 Precision
• Clause 11 Test report

That structure matters in practice because it separates the sampling rules, test setup, calculation, repeatability check, and reporting requirements.

What are the key requirements of ISO 4576?

ISO 4576 defines a simple laboratory workflow: dilute the dispersion with deionized water, filter it through a specified metal gauze, wash the residue, dry it to constant mass, and weigh it. The result is then calculated as a percentage of the test portion.

Sampling and timing

Clause 7 requires sampling by ISO 123 or ISO 15528 to obtain a homogeneous sample. Visible skin and skin fragments larger than 5 mm are to be avoided, the sample is filtered before testing through a mesh of at least 0.4 mm, and the test is carried out within 10 min after sampling. This keeps the sample representative and reduces changes before the measurement starts.

Reagents and apparatus

Clauses 5 and 6 require deionized water, with a surfactant used if needed to stabilize the dispersion during testing. The apparatus includes test sieves made of metal gauze to ISO 3310-1, supports such as steel rings or glass funnels, balances with different accuracies, an oven or vacuum oven, desiccators, a beaker, and filtration apparatus. In practice, this means the laboratory needs controlled sieve size, reliable mass measurement, and a drying step that can be repeated to constant mass.

Sieve choice and drying

Clause 6 gives mesh apertures in the range from 45 μm to 180 μm, with the exact aperture chosen according to the sample specification. Clause 8 requires the sieve to be cleaned, dried to constant mass, weighed, and then dried again after filtration at 105 °C as preferred, or at 125 °C or 140 °C if the dispersion requires it. The chosen temperature depends on polymer stability and additives, so the lab has to match the drying condition to the material under test.

Filtration, washing, and weighing

Clause 8 requires the diluted dispersion to be poured onto the sieve, washed until a clear filtrate is obtained, then dried and reweighed after repeated drying periods. Two determinations are required. This ensures the residue measured is the retained coagulum and not water still held in the sample.

Result calculation and acceptance

Clause 9 gives the calculation of sieve residue as a mass percentage and requires the arithmetic mean of the two determinations for each sieve, rounded to one decimal place. The two individual results must agree within ±5% of the mean, otherwise two further determinations are carried out. Clause 10 states an estimated same-day repeatability of ±8% when the method is performed by the same person with the same apparatus on the same sample.

Reporting

Clause 11 requires the test report to identify the standard used, the dispersion tested, the sieve and drying temperature, the sieve residue, a description of the residue, unusual observations, any deviations or optional steps, and the test date.

Which standards are used with ISO 4576?

ISO 4576 cites three normative references:

• ISO 123 - sampling of rubber latex, used as one of the sampling methods for obtaining a homogeneous sample
• ISO 3310-1 - technical requirements and testing for metal wire cloth test sieves, used for the sieve specification
• ISO 15528 - sampling of paints, varnishes and raw materials for paints and varnishes, used as another sampling method

These references matter because they link the method to recognized sampling practice and to standardized test sieves.

What changed in ISO 4576 from the previous edition?

ISO 4576 is the third edition and replaces ISO 4576:1996. The stated changes are an updated foreword, updated normative references, the addition of Clause 3 for terms and definitions, added general laboratory instruments in Clause 6, added filtering before testing, added a test time after sampling, added test sieve cleaning, and an updated procedure.

What does the ISO 4576 document contain?

ISO 4576 contains the scope, references, principle, reagent list, apparatus list, sampling instructions, step-by-step procedure, result calculation, precision statement, and test report content. It also includes Figure 1, which shows an example filtration apparatus.

The document is written as a practical lab method, so it gives the sequence of preparation, filtration, washing, drying, and weighing needed to measure residue on a specified sieve. It also states the balance accuracies, sieve aperture options, and drying temperatures that a laboratory has to control. The formula in Clause 9 and the precision statement in Clause 10 support consistent reporting and result review.

International
Standard
ISO 4576
Third edition
Plastics — Polymer dispersions —
2026-11
Determination of sieve residue
Plastiques — Dispersions de polymères — Détermination du
résidu par tamisage
Reference number
© ISO 2026
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Sampling . 3
8 Procedure . 4
9 Expression of results . 4
10 Precision . 5
11 Test report . 5

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 9, Thermoplastic
materials.
This third edition cancels and replaces the second edition (ISO 4576:1996), which has been technically
revised.
The main changes are as follows:
— the normative references has been updated (see Clause 2);
— the mandatory terms and definitions clause (see Clause 3) has been added, and subsequent clauses have
been renumbered;
— "general laboratory instruments" has been added in the apparatus clause (see Clause 6);
— filtering requirements before test has been added;
— a test time after sampling has been added;
— test sieve cleaning has been added;
— the procedure has been updated.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 4576:2026(en)
Plastics — Polymer dispersions — Determination of sieve
residue
1 Scope
This document specifies a method of determination of the sieve residue (gross particle and coagulum
content) of polymer dispersions.
This document is only applicable to coagulum type content.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitut
...