Method for Determination of Paint Film Flexibility (GB/T1731-93) This standard specifies the method for measuring the flexibility of paint film using a flexibility Tester, and the flexibility of the paint film is expressed by the smallest shaft diameter that does not cause damage to the paint film
(1) Materials and instruments
① Bottom plate: The bottom plate should be flat and curved without any visible cracks and wrinkles on the surface. Unless otherwise specified, the bottom plate shall be 120mmx25mmx(0.2~0.3)mm tinplate.
②4x magnifying glass.
③Flexibility Tester: As shown in Figure 10-11, the flexibility Tester is fixed on the base by 7 steel shafts with different diameters (1mm, 2mm, 3mm, 4mm, 5m, 10mm, 15m in diameter) consist of.
(2) Operation steps
① Unless otherwise specified, the test should be carried out in accordance with the constant temperature and humidity conditions specified in GB/T9278.
②Use both hands to press the paint film of the test panel upwards on the shaft rod with a specified diameter, and use the strength of two thumbs to bend the test board around the shaft rod within 2 to 3 seconds. After bending, the two thumbs should be symmetrical to Shaft centerline.
③ After bending, use a 4x magnifying glass to observe the paint film. Check whether the paint film is damaged by texture, cracks and peeling.
