ASTM D7187 Standard Test Method for Measuring Mechanical Aspects of Scratch/Marsh Behavior of Paint Coatings with Nano Scratching

EUROLAB laboratory provides testing and compliance services within the scope of ASTM D7187 standard. The ASTM D7187 standard covers a nanoscratch method for determining the scratch/exposure resistance of paint coatings on smooth flat surfaces. This test addresses two limitations of existing mar tests, such as Test Methods D1044, D3363, D5178, D6037, and D6279.

Other methods used in scratch/margin assessment, physically scratch or scratch the surface of a sample with single or multiple contact cutting and then use visual inspection to assign a sequence. It has been accepted that the loss of appearance is mainly due to the surface damage created.

This method quantitatively and objectively measures scratch/mar behavior by making the evaluation process two steps with an emphasis on surface damage. The first step is to find the relationship between damage shape and size and external input (such as forces, contact geometry, and deformation). The second step is to correlate the shape and extent of the damage with the visual loss of gloss. The first step is covered by this method; In addition, an accompanying survey provides an experimental example to correlate damage with change in brightness.

There are three basic deformation mechanisms: elastic deformation, plastic deformation and fracture; only the last two contribute significantly to mar. This method evaluates the scratch/mar condition based on the last two damage mechanisms.

While this standard was developed for paint coatings, it can also be applied to other similar types of polymer-based coatings, for example varnishes, varnishes, varnishes and other decorative and protective layers applied over hard substrates.

This test provides a quantitative assessment of the mechanical aspects of the scratch/mar behavior of a paint coating under various conditions. The ability to control test variables such as loading speed, speed and temperature allows the examination of scratch/mar behavior in a variety of environments. This test method is particularly suitable for the measurement of paint coatings on laboratory test panels.

The accuracy and precision of scratch/mar performance can be significantly affected by pavement surface unevenness and irregularities.

In field studies, a correlation was observed between good mar resistance and the combination of high plastic resistance and high fracture resistance. There have been conflicting results in field studies when coatings have either high plastic strength and low fracture resistance, or low plastic strength and high fracture resistance.

Mar resistance characterizes the coating's ability to resist light damage. The difference between mar and scratch resistance is that mar only refers to relatively fine surface scratches that spoil the appearance of the coating. The mechanical aspects of Mar resistance depend on the complex interaction between visco-elastic and thermal recovery, yielding or plastic flow, and microcracking. Polymers are challenging because they exhibit a range of mechanical properties, from liquid to rubbery materials to brittle solids. Mechanical properties are speed and temperature dependent, and viscoelastic recovery can cause scratches to change over time. One such test for evaluating polymeric coatings and plastics is Test Method D7027.

Since this method measures mechanical properties such as forces and displacements (deformations) during the damage generation process, velocity dependence, temperature dependence, and visco-elastic-plastic recovery can be further investigated and the visual effects of damage can be associated with deformation.

Values ​​stated in SI units should be accepted as standard. Values ​​in parentheses are for informational purposes only.

This standard does not purport to address all, if any, safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health and environmental practices and to determine the applicability of regulatory restrictions prior to use.

Our organization, EUROLAB, provides standard test method services to measure the mechanical aspects of scratch/mart behavior of paint coatings with nano scratching, within the framework of national and international standards, with its trained and expert staff and advanced technological equipment, among numerous test, measurement, analysis and evaluation studies. Provides testing services within the scope of ASTM D7187 standard.