ISO 11909:2025

International
Standard
ISO 11909
Third edition
Binders for paints and varnishes —
2025-10
Polyisocyanate resins — General
methods of test
Liants pour peintures et vernis — Résines de polyisocyanate —
Méthodes générales d'essai
Reference number
© ISO 2025
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Properties and test methods . 2
Annex A (normative) Determination of isocyanate (NCO) content (percentage by mass of
isocyanate groups) . 3

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 35, Paints and varnishes, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 139, Paints and varnishes,
in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 11909:2007), which has been technically
revised.
The main changes are as follows:
— in A.5, potentiometric titration has been introduced as a general alternative to titration using a colour
indicator, not only in the case of highly coloured resins;
— CAS-numbers have been added to the reagents;
— the normative references have 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 11909:2025(en)
Binders for paints and varnishes — Polyisocyanate resins —
General methods of test
1 Scope
This document provides general test methods for polyisocyanate resins and solutions of polyisocyanate
resins intended for use as binders in paints, varnishes and related products.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1523, Determination of flash point — Closed cup equilibrium method
ISO 2811-1, Paints and varnishes — Determination of density — Part 1: Pycnometer method
ISO 2811-2, Paints and varnishes — Determination of density — Part 2: Immersed body (plummet) method
ISO 2811-3, Paints and varnishes — Determination of density — Part 3: Oscillation method
ISO 2811-4, Paints and varnishes — Determination of density — Part 4: Pressure cup method
ISO 3219-2, Rheology — Part 2: General principles of rotational and oscillatory rheometry
ISO 3219-3, Rheology — Part 3: Test procedure and examples for the evaluation of results when using rotational
and oscillatory rheometry
ISO 3251, Paints, varnishes and plastics — Determination of non-volatile-matter content
ISO 3679, Determination of flash point – Method for flash no-flash and flash point by small scale closed cup tester
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4630, Clear liquids — Estimation of colour by the Gardner colour scale
ISO 6271, Clear liquids — Estimation of colour by the platinum-cobalt colour scale
ISO 10283, Binders for paints and varnishes — Determination of monomeric diisocyanates in isocyanate resins
ISO 15528, Paints
...