This standard specifies methods for determining the adhesion by carrying out a pull-off test on a single coating or a multi-coat system of paint, varnish or related product.
This standard have been found useful in comparing the adhesion behaviour of different coatings. It is mostuseful in providing relative ratings for a series of coated panels exhibiting significant differences in adhesion.
This standard is applicable to wide range of substrates. Different procedures are given according to whether the substrate is deformable, for example thin metal, plastics and wood, or rigid, for example thick concrete and metal plates. For special purposes, the coating may be applied directly to the face of a test dolly.
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)
GB/T 13452.2 Paints and Varnishes — Determination of Film Thickness (GB/T 13452.2-1992, idt ISO 2808:1974)
ISO 1513:1992 Paints and Varnishes — Examination and Preparation of Samples for Testing
3 Principle
The product or system under test is applied at uniform thickness to flat panels of uniform surface texture.
After drying/curing the coating system, dollies are bonded directly to the surface of the coated, cured panel using an adhesive.
After curing of the adhesive, the bonded dolly assemblies are placed in a suitable tensile tester. The bonded assemblies are subjected to a controlled tensile test (pull-off test), and the force required to break the coating/substrate bond is measured.
The test result is the tensile stress necessary to break the weakest interface (adhesive failure) or the weakest component (cohesive failure) of the test assembly. Mixed adhesive/cohesive failures may also occur.
