UNE-EN 62788-1-6:2017

This standard defines the terminology, test equipment, test environment, specimen preparation, test procedures, and test report for measuring the degree of cure of Ethylene-Vinyl Acetate (EVA) encapsulation sheet used in photovoltaic (PV) modules. The differential scanning calorimetry (both residual enthalpy and melt/freeze protocols) and gel content methods are included here. This procedure may be used by material- or module-manufacturers to verify that the cross-linking additive is present and is active. The procedure may also be used to verify the module manufacturing (lamination) process for the purposes of quality- and process-control. The procedure may also be used to assess the uniformity of the EVA formulation within a roll as well as to compare variation of the EVA formulation from roll to roll. This procedure may be applied to uncured or recently cured EVA sheet as well as uncured or recently cured EVA from PV modules.NOTE: This test procedure may also be applied to cross-linking ethylenic co-polymers other than EVA. The temperatures identified for the calorimetry measurements in this procedure have been optimized for EVA. Therefore, if the test procedure is applied to other encapsulation materials, the range of the test temperatures may have to be adjusted based on the active temperature of the curing agent and/or the melt/freeze temperature of the base material.