Low Heat Distortion Properties in Glass filled PET

[arrondee]

I am making a glass filled PET compound on a twin screw extruder. Properties are good except for an extremely low HDT value of approx 80 C instead of 215 which commercially available grades have. I still get this low number even when I use an alternative grade of PET. Strand length in the compound is good, no excessive breakage.

Does anyone have any ideas on how to improve this property?

 

[patprimmer]

80 deg C is a low HDT for PET, even unfilled. Are you useing homopolymer or copolymer, is it crystalised or amorphous. is it PETG.

Many beverage bottle compounds are amorphous copolymer.

Are you useing a glass fibre with good aspect ratio and suitable surface coating or sizeing agent

Regards
pat