Film tests include negative impact, impact, bending tests, etc.
Many paint manufacturers now offer these parameters of paint, adhesion, bending, etc. The impact strength is expressed by KG.CM and KG/CM^2. The values ​​are the same, such as 40 kg.cm and 40 kg/cm^2.
Paint suppliers use 40kg/cm^2, which they call kilogram force. Southern urban paint manufacturers use this representation.
The impact strength according to the Chinese national standard GB is 1KG weight falling from a CM height, while hitting the custom impact head, the impact head again impacts the paint film front, after seeing the impact, there is no shedding\cracking. If a paint is 1KGç The code is dropped from a height of 50cm, and the impact is free from cracks and shedding. The impact strength of the paint is 1KG.50CM or 50kg.cm. This 1KG.50CM is also the qualification standard for most domestic paints. This impact instrument is sold outside (according to GB/ T1732-93 Design and manufacture Ability of the coating to withstand deformation under high-speed load The maximum height of a coating with a fixed mass falling on the test plate without causing damage to the coating, expressed in cm. Impact performance measurement 1. Equipment and equipment: (1) The weight of the weight is 1000±1g and it can move freely in the slide.(2) The ball on the punch meets the requirements of B3088IV.The center of the impact is aligned with the center of the anvil groove. The depth of the head into the groove is 2±0.1mm (3) The scale on the slider is 0-50±0.1cm and the index is 1cm.(4) Fourfold magnifying glass.
The test board for painting is a tinplate of 0.5mm in accordance with the standard. After grinding, it is sprayed with 20μm of paint to be tested, and it is naturally dried for 7 days before being tested.
Kg/cm^2 This unit is the adhesion standard and comes from the ISO international standard. There is a special instrument test. The principle is to use a high-strength adhesive on a dry paint film surface, and then use a special drawing instrument. Pull down, the glue will not break, the break is the part between the paint film and the substrate, the instrument will show how much tension is broken when the kg/cm^2. That is how many kilograms of tension per square centimeter.
According to GB and ISO and Japanese JIS standards, the bending test is to use a 1 to 10mm metal shaft bent on a 0.5mm tinplate plate 20 microns dry film, no cracks and fall off, then the bending test result is how many mm, of course, the smaller the number it is good.
supplement:
1. The shock expression method indicated by kg/cm^2 I really did not encounter, I said earlier PULL OFF (drawing instrument method) adhesion is expressed with this, can also be expressed in MPa.
The ISO and ASTM standards are the same for the standard content of this pull instrument test.
The cm of 2.40kg.cm is the height of the weight, and the area of ​​cm^2 of 40kg/cm^2 represents the area. It seems that it cannot be the same.
3. Generally more advanced mechanical \ steel topcoat and primer impact have to get 50kg cm. Especially when there are decorative effects, such as railway passenger car paint \ truck paint. If it is a relatively heavy equipment, usually less bump, just decorative and anti-corrosion, you can relax a little.