ISO 20566-2020 “Paints and varnishes – Determination of scrubbing resistance of coating systems by laboratory car cleaning methods”

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This document has been prepared by ISO/TC 35 (Paints and varnishes) Technical Committee, SC 9 Sub-Committee (General test methods for paints and varnishes) in cooperation with the Technical Committee CEN/TC 139 (Paints and Varnishes) of the European Committee for Standardization (CEN) in accordance with the ISO/ CEN Technical Cooperation Agreement (Vienna Agreement).

The third edition cancelled and replaced the technically revised second edition (ISO 20566:2013). The main changes from the previous edition are as follows:

– The term “Control panel” has been changed to “reference Panel”;

— The requirement on the temperature of washing suspension is deleted;

– Verification using plastic panels is added to Appendix A;

— The text has been edited and revised, and the normative references have been updated.

Any feedback or questions about this document should be directed to the user’s national standards body. A complete list of these institutions can be found at

ISO 20566-2020 “Paints and varnishes – Determination of scrubbing resistance of coating systems by laboratory car cleaning methods”

With this testing procedure, it is important to note that test results do not remain the same over time due to changes in brush materials. As brushes age, the testing will become more serious. Therefore, the test program is only suitable for comparison tests performed at any time, and uses relatively short runs. Readings obtained using devices that accumulate different total hours of operation are not comparable to each other.

1 range
This document specifies test procedures for assessing the scratch resistance of organic paint coatings, particularly those used in the automotive industry (i.e. for assessing their car wash resistance). Machine-based washing is simulated in a laboratory environment using a rotating brush and synthetic dirt. The test conditions are designed to be as close as possible to the real conditions at the car wash. This method can also be used to test protective plastic films and plastic parts if the test parameters are selected properly.

2 Normative references
The following files are referenced in the text in such a way that some or all of the content constitutes the requirements of this document. For dated references, citation-only versions apply. For undated references, the new version of the reference (including any revisions) applies.

ISO 1513, Paints and varnishes – Examination and preparation of test samples

ISO 2813, Paints and varnishes — Determination of glossiness values at 20°, 60° and 85°

ISO 4618, Paints and varnishes — Terms and definitions

ISO 4628-1, Paints and varnishes – Assessment of coating degradation – Designation of intensity of uniform variation in number and size of defects and appearance – Part 1: General introduction and designation of systems

ISO 13076, Paints and varnishes – Lighting and procedures for visual evaluation of paints

ISO 13803, Paints and varnishes — determination of mist in 20° paint films

ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling

ISO 18314-1, analytical colorimetric methods – Part 1: Practical color measurement

ISO 20566-2020 “Paints and varnishes – Determination of scrubbing resistance of coating systems by laboratory car cleaning methods”

3 Terms and Definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and the following articles apply.

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3.1 Dual-Channel

Test a single forward and backward movement of the panel bracket

3.2 Test Area

Area of assessment

3.3 Effect of reflow welding

The ability of coating surfaces to recover after damage such as scratches

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