ISO 4907-4:2025

International
Standard
ISO 4907-4
First edition
Plastics — Ion exchange resin —
2025-03
Part 4:
Determination of particle size by
laser diffraction method
Plastiques — Résine échangeuse d'ions —
Partie 4: Détermination de la taille des particules par la méthode
de diffraction laser
Reference number
© ISO 2025
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Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
3.1 Terms and definitions .1
3.2 Symbols .2
4 Principle . 2
5 Reagents . 2
6 Apparatus . 2
7 Pretreatment . 2
8 Procedure . 3
8.1 Instrument preparation .3
8.2 Testing parameter setting .3
8.3 Testing the sample .3
9 Calculation . 4
9.1 Percent below specified lower size .4
9.2 Percent above specified upper size .4
9.3 Percent between specified range size .4
9.4 Effective size.4
9.5 Median size .5
9.6 Uniformity coefficient .5
9.7 Area-weighted mean size .5
9.8 Volume-weighted mean size .5
10 Repeatability . 5
10.1 Repeatability of effective size .5
10.2 Repeatability of median size .5
10.3 Repeatability of uniformity coefficient .5
10.4 Repeatability of area-weighted mean size .6
10.5 Repeatability of volume-weighted mean size .6
11 Test report . 6

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Foreword
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This document was prepared by Technical Committee ISO/TC 61, Plastic, Subcommittee SC 5, Physical-
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