This standard specifies an empirical test procedure for assessing the resistance of a coating of paint, varnish or related product to cracking and/or detachment from a metal or plastic substrate when subjected to bending round a cylindrical mandrel under standard conditions.
For a multicoat system, each coat may be tested separately or the complete system may be tested.
The method specified may be carried out:
— either as a “go/no go” test, by carrying out the test with a single specified size of mandrel, to assess compliance with a particular requirement;
— or by repeating the procedure using successively smaller mandrels to determine the diameter of the first mandrel over which the coating cracks and/or becomes detached from the substrate.
Two types of apparatus are specified, Type I being appropriate for use on test panels of thickness up to 0.3mm, and Type II for use on test panels of thickness up to 1.0mm. Both types of apparatus have been found to give similar results with the same coating, but normally only one will be used for testing a given product.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 3186-2006 Paints Varnishes and Raw Materials for Paints and Varnishes — Sampling (ISO 15528:2000, IDT)
GB/T 9271 Paints and Varnishes — Standard Panels for Testing (GB/T 9271-1988, eqv ISO 1514:1984)
GB 9278 Temperatures and Humidities for Conditioning and Testing of Paint Specimens (GB 9278-1988, eqv ISO 3270:1984, Paints and Varnishes and Their Raw Materials — Temperatures and Humidities for Conditioning and Testing)
