Impact strength
The impact strength test is the ability of the coating film to resist instantaneous deformation without cracking or falling off under the action of high-speed gravity. It comprehensively reflects the flexibility of the coating film and the bonding force to the substrate.
According to GB/T1732-93, the mass of the hammer of the impact Tester is 1000g, the diameter of the groove is 15mm±0.3mm, the depth of the punch entering the groove is 2mm±0.1mm (subject to correction), and the maximum drop height of the weight is 50cm. Expressed in N cm. The quality and height of the weight of the impact Tester vary from country to country, and ISO6272-1993 defines it as a drop weight test with a weight of 1kg and a height of 1m.
The quality assessment after the test generally uses a 4x magnifying glass to observe whether there are cracks and damages, but it is difficult to observe very fine cracks, and some use CuS04 aqueous solution to wet for 15 minutes, and observe whether there is copper or rust color to judge.
flexibility
According to GB/T1731-93, the flexibility Tester has a set of steel rods with different thicknesses, which are bent at 180° to check whether the paint film is cracked or not. The minimum rate without paint film damage is represented by the diameter of the rod. The rod diameters are 1mm, 2mm, 3mm, 4mm, 5mm, 10mm, 15mm respectively. The test result is a comprehensive reflection of the elasticity, plasticity and adhesion of the paint film, and is affected by the deformation time and speed during the test.
Another type of flexibility Tester is the conical bend Tester, which avoids the discontinuity of the rate-by-rod test results.
