If there's any doubt then best to contact the manufacturer (GMP)
Most Nylon type materials inject between 520F & 560F (271-294C)
Duraflex is a newer generation material and is 446/230, and Valplast is around 560/294 but users should check the recommended temps to match up best with the type of machinery they're using to do the injection process. I believe the old valplast instruction brochure stated melting at 600/315.
Flexite acetal is 475 and Myerson's is 392 so check carefully to avoid screw-ups when using these materials.
If in doubt - check it out. fwiw.
edit to say i've had a peep in my files to look up some info.
The scientific 'melting point' from the MSDS file on 'flexite plus' says 370F/188C, but the 'melting temperature' that the material is held at for a pre-determined duration to allow suitable flow is higher. Just wanted to say this to make it clear there's a distinction between the two figures & applies for all materials.