ISO 4624:2016 pdf free
ISO 4624:2016 pdf free.Paints and varnishes – Pull-off test for adhesion
Tensile tester, suitable for carrying out the chosen procedure specified in Clause 8. The tensile stress shall be applied in a direction perpendicular to the plane of the coated substrate and shall be increased at a substantially uniform rate, not greater than 1 MPa/s1) such that failure of the test assembly occurs within 90 s. Suitable designs for applying the tensile stress are shown in Figures 1 and 2.
Instead of a tensile tester, other types of pull-off adhesion testers (mechanically, pneumatically, hydraulically or hand-driven) may be used provided that they give similar results. The type of instrument shall be reported in the test report, because hand-driven/mechanical/ hydraulic instruments are reported to produce widely different results.
NOTE The results can be influenced by the test assembly used. Furthermore, the results are not reproducible unless coaxial alignment of the tensile forces is ensured.
Test dollies, each consisting of a steel or aluminium cylindrical-faced testing body, specifically designed to be used with the tensile tester. Each dolly has a rigid, flat face for bonding the adhesive/coating at one end and a facility for connecting the pull-off tester at the other. Each dolly has a nominal diameter of 20 mm (see, however, following paragraph) and sufficient thickness to ensure freedom from distortion during the test. It is recommended that the length of each dolly is not less than half its diameter. The faces of each dolly shall be machined perpendicular to its axis before use.
Dollies with a diameter of, for example, 7 mm may be used when the method for testing adhesion from one side only is used and when there is a danger of distortion of the substrate (see 8.4.2). If dollies smaller in diameter are used, more measurements shall be made to improve the precision. When using 7 mm dollies, 10 measurements have been shown to be practicable. The diameter of the dollies shall be reported in the test report.
Centering device, for ensuring proper coaxial alignment of the test assembly during the adhesion process of the two-dolly methods described in 8.4.1 (method A) and 8.4.3 (method C). A suitable design is shown in Figure 3.
Cutting device, such as a sharp knife, for cutting through cured adhesive and the paint coating to the substrate, round the circumference of the dolly.ISO 4624 pdf download.
