Expandable Polystyrene Bead Foam Replacement: Final Report

摘要

Samples of three different expandable polystyrene bead material, obtained from two suppliers, were evaluated as replacement material for a discontinued product used for the last 10 years as an encapsulant for electronic packages. Large quantities of two of the materials were purchased for more detailed evaluation. Compressive and tensile properties of these materials were determined as a function of foam density and test temperature. These properties were found to be equivalent to the properties of the current material. Pre-expansion and screening processes were determined to be the same as those currently required. Both new materials were found to be more thermally stable during the fusion cycle, which should help in the encapsulation of larger electronic packages. Acceptable foam could be molded from both, with a lower volatile content. This will allow for longer shelf life of the pre-expanded beads and reduce their scrap rate. Tests conducted at Sandia National Laboratory Albuquerque (SNLA) revealed no obvious material incompatibility with one of the new materials (Type A). Type A material has been approved to replace the current material. Plans are to add the second new material (Type B) as an alternate. Type A material has been purchased and is currently being used in production. This change-over occurred without any production delays. 7 refs., 15 figs., 11 tabs. (ERA citation 13:040425)