Performance indicators of paint products -- What is the impact strength of paint products

Impact strength test of paint films: The impact test measures the ability of a paint film to withstand rapid deformation without cracking; a heavy object is dropped along a guide onto a hemispherical indenter placed on the sample, causing the sample to deform. Beneath the template, there is a recessed seat facing the pressure head. Gradually raise the heavy object until the paint film cracks. If the paint film is directly impacted by the punch from above, it is called direct impact. When the paint film faces downward, it is called backflow. Recoil is more severe than thrust, because recoil is expansion while thrust is compression. If the substrate is thick enough, it will not deform under impact. Then almost any paint film can pass through. Slight surface differences in floors of the same type but different batch numbers can also affect the test results. The thickness of the coating film, the thickness of the substrate, and surface treatment all affect the impact strength results, hence standardization is required. Impact strength indicates the flexibility of the paint film and its adhesion to the substrate. Impact resistance actually refers to the rapid deformation caused by an impact load; it differs from the performance of a paint film under static load, as the latter is also influenced by factors such as plasticity and time, whereas this issue does not arise under impact load. The instrument used to measure impact resistance is an impact tester; a weight of a certain mass is dropped onto the coated sample, and the maximum height at which the coating can undergo elongation without breaking is determined. The impact resistance of the coating is expressed as the product of the weight of the hammer and this height. The paint film is generally used in the glassy region. In impact tests, the rate of change of the paint film morphology is very high, and the rate of stress relaxation is key to the impact strength test. The secondary transition temperature in the glassy region is the temperature at which local movement of the main chain and side groups begins; the lower the temperature, the greater the relaxation rate following impact. However, the deformation caused by impact is a significant chain movement, which does not occur in the glassy region as described in this article. Another explanation is that the second transition temperature in the dynamic mechanical spectrum is measured at low frequency regimes, while the impact frequency is extremely high. Equivalent to temperature and time, that means moving towards higher temperatures. At the impact rate, the movement of the main chain may be induced, thereby causing a greater degree of movement in the chain. In practice, the secondary transition temperature is highly correlated with impact strength. Impact testing is sensitive to the integrity of the paint film, so it can also determine the degree to which water-dispersed coatings coalesce into a film.