ASTM D2578-09 pdf free download.Standard Test Method for Wetting Tension of Polyethylene and Polypropylene Films.
1 .1 This test method covers the measurement of the wetting tension of a polyethylene or polypropylene film surface in contact with drops of specific test solutions in the presence of air.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.
4.1.1 The right side of the above equation (the difference between the surface energies of the gas - solid and solid - liquid interfaces) is defined as the wetting tension of the solid surface. It is not a fundamental property of the surface but depends on interaction between the solid and a particular environment.
4.1.2 When the gas is air saturated with vapors of the liquid. will he the surface tension of the liquid. If the angle of contact is 00 the liquid is said to just wet the surface of the solid, and in this particular case (since cos 0 = 1) the wetting tension of the solid will be equal to the surface tension of the liquid.
4.2 The ability of polyethylene and polypropylene films to retain inks, coatings, adhesives, etc.. is primarily dependent upon the character of their surfaces, and can be improved by one of several surface-treating techniques. These same treating techniques have been found to increase the wetting tension of a polyethylene or a polypropylene film surface in contact with mixtures of formamide and ethyl Cellosolve in the presence of air. it is therefore possible to relate the wetting tension of a polyethylene or a polypropylene film surface to its ability to accept and retain inks, coatings, adhesives, etc. The measured wetting tension of a specific film surface can only be related to acceptable ink, coating, or adhesive retention through experience. Wetting tension in itself is not a completely acceptable measure of ink, coating, or adhesive adhesion.
7.3 Fully prepared mixtures of these reagents in varying concentrations are available from a number of commercial sources. Pens containing these mixtures are also commercially available. However, correlations between these options and freshly prepared solutions have not been established.
8. Hazards
8. 1 Formamide may cause skin irritation and is particularly dangerous in direct contact with the eyes. Safety goggles should be worn when making up new test mixtures.
8.2 Ethyl Cellosolve is a highly flammable solvent.
8.3 Both ethyl Cellosolve and formamidc arc toxic and pose exposure risks. Consult the applicable MSDS before use and ensure that the appropriate Personal Protective Equipment (PPE) is used, especially when preparing new solutions.
8.4 All tests should be performed with adequate ventilation.
9. Sampling
9. 1 The minimum amount of film required for this test depends upon the skill of the operator. This usually amounts to one sample across the entire width of a roll in order to obtain a representative value.ASTM D2578 pdf download.