1 Scope
This part of GB/T 20624 specifies a method for evaluating the resistance of a dry film of paint, varnish or related product to cracking or peeling from a substrate when it is subjected to a deformation caused by a falling weight, with a 20-mm-diameter spherical indenter, dropped under standard conditions.
Note: The term “impact resistance” is included in the title of this standard, but one important characteristic of the apparatus used is that it should produce rapid deformation rather than a true impact.
The part is applicable to:
— either as a pass/fail test, the test being carried out from one drop height and with a specified mass, so as to test compliance with a particular specification;
— or as a classification test, to determine the minimum mass and/or drop height for which the coating cracks or peels from its substrate by gradually increasing the drop height and/or the mass.
2 Normative References
The following normative document contains provisions which, through reference in this text, constitute provisions of this part of GB/T 20624. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 3186 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)
Foreword II
1 Scope
2 Normative References
3 Required Supplementary Information
4 Apparatus
5 Sampling
6 Test Panels
7 Procedure
8 Precision
9 Test Report
Annex A (Normative) Required Supplementary Information
