ISO 22785-5:2026

International
Standard
ISO 22785-5
First edition
Paints and varnishes — Coatings on
2026-08
plastics and composites —
Part 5:
Chemical resistance testing
Peintures et vernis — Revêtements sur plastiques et
composites —
Partie 5: Essais de résistance aux produits chimiques
Reference number
© ISO 2026
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sample composition and preparation . 1
4.1 Samples .1
4.2 Conditioning.2
5 Methods for testing . 2
5.1 General influences .2
5.2 Immersion into the test chemicals or solution.2
5.3 Method using an absorbent medium .2
5.4 Spotting methods .2
5.5 Temperature-gradient oven method .2
5.6 Chemical load of electrical and electronic equipment .3
6 Chemicals for testing . 3
6.1 General .3
6.2 Fuels and operating materials .3
6.3 Laboratory chemicals .4
6.4 Biological substances . .4
6.5 Substances of daily use .4
7 Evaluation . 5
7.1 General .5
7.2 Influence of the plastics substrate on the chemical resistance test .5
7.2.1 General .5
7.2.2 Temperature sensitivity .5
7.2.3 Volume change due to test substances .5
Bibliography . 7

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
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rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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This document was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9,
General test methods for paints and varnishes.
A list of all parts in the ISO 22785 series can be found on the ISO website.
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
Introduction
The ISO 22785 series explains the characteristics of plastics and the differences between plastics substrates
and metallic substrates.
Even though chemical resistance testing is usually a surface test, the substrate has an influence on the
chemical resistance of the coating and is also considered during the test.

v
International Standard ISO 22785-5:2026(en)
Paints and varnishes — Coatings on plastics and
composites —
Part 5:
Chemical resistance testing
1 Scope
This document specifies chemical resistance testing of coatings on plastics, plastics composites and similar
substrates, hereinafter collectively referred to as plastics.
This document shows the potential effect of plastics on the behaviour of the coating during chemical
resistance testing.
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 4618, Paints and varnishes — Vocabulary
ISO 22785-1, Paints and varnishes — Coatings on plastics and composites — Part 1: General introduction
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and ISO 22785-1 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Sample composition and preparation
4.1 Samples
Coatings on specimen plates specified in ISO 1514 as well as coatings on components are tested. Depending
on the selected test method, there are different requirements for the sample geometry. In particular, for
continuous drip methods and exposure through filter papers, flat specimens are a prerequisite.
Defects and damage of all kinds in the substrate affect the appearance and characteristics.
The coating system and the substrate are selected together with the pre-treatment and coating methods so
that a homogeneous coating is achieved. The coating thick
...