ASTM F2217/F2217M is a standard practice that covers the procedure for determining the weight of a coating or adhesive applied to a substrate. This practice is primarily applicable to coated substrates such as films, paper, and nonwovens. The weight of the coating can be an indicator of certain functional characteristics of coated substrates, such as sealability, peelability, and appearance.
The weight of the coating can affect several aspects of a coated substrate. For example, the coat weight might influence the sealability of the substrate, which refers to how effectively the substrate can be sealed. The weight can also affect the peelability or the ease with which the coating can be removed from the substrate, as well as the overall appearance of the coated substrate. Therefore, accurate determination of the coat weight is an important part of quality control for products that use coated substrates.
However, this standard practice does not provide any criteria for deciding whether a certain coat weight is acceptable or not. Instead, the acceptability criteria should be determined jointly by the user and the producer of the product, according to their specific requirements and applications.
A key part of the methodology described in this standard is the operator's assessment of the effective removal of the coating. This step is somewhat subjective and can vary from one operator to another. As a result, operator training is necessary to ensure that the assessment is carried out consistently.
The solvent used for removing the coating is critical to the success of the process. The coated substrate manufacturer must provide guidance on the appropriate choice of solvent, which should be capable of dissolving only the coating, not the substrate itself.
ASTM F2217/F2217M expresses the amount of coating in terms of weight per given area, such as grams per square meter (g/m2) or pounds per ream (lb/ream).