Why is PCM gap filler phase change temperature 60°?

A: The 60 ° phase change temperature was selected for two reasons.
First, it was a low enough temperature for the phase change to
occur in applications. Second, it would not phase change in
transport. GLPOLY studies show that shipping containers can
reach 55° in domestic and international shipments. The higher
phase change temperature eliminates the possibility of a product
being ruined in shipment.