Temperature and PU Density

the PU reaction is exothermic ( gives off heat)

the reaction also creates CO2 which lowers the density by creating gas

you may remember from chemistry PV=nRT

pressure x volume = constant x Temperature

depending on your surfactant package:

if the belt is colder then the material will be denser on the outside layer than in the core (becomes a structural type foam)

which will increase the overall density

hope his helps?

Raising or lowering the temperature will change the internal pressure.

But if the dispensing rate is constant and the panel thickness does not change, the PU density must remain constant.

PU density is mass per unit volume.

As soon as the PU reaches adequate cure, the internal pressure can no longer change the density.