I agree with Baitjunky's - A standard N95 particulate filter is not useful when melting / curing plastisol as it's is made for particulates and has no defense towards emitted fumes.
Good Ventilation, Exhaust systems, and a Paint / Chemical Respirator is recommended. Below is our companies SDS wording on Hot Melt Plastisol's.
'During heating of product, vapors and gases may be released
that the end-user needs to take precautions to avoid employee exposure (such
as ventilation, or respiratory protection).'