Using a too-hot adhesive on foam substrates is more likely to lead to a sticky mess than a suitable bond. If you're using foam in your packaging materials, you'll want to choose a lower temperature hot melt adhesive. While many hot melt adhesives are applied at temperatures of up to 400F degrees, there is a range of lower-temperature hot melt adhesives that are designed to be applied at a lower temperature. Using a lower temperature hot melt that is designed for foam will help you avoid many issues related to melting.