QUESTION: Can you apply for a design patent for a product after the utility patent expires on lifetime term? Was wondering if a design patent was possible if the original utility patent had lifetime expired.
ANSWER: Mostly likely, no.
A design patent must be new and not obvious in order to be valid. This is the same for utility patents.
If your utility patent covers the same product as your design patent, it is likely that the utility shows the features to be covered in the design patent.
If all of the features in the design patent are shown in the utility patent, then your design patent would not be new. Likewise, if the features in the design patent are mostly shown in the utility patent, then your design patent might likely be considered as obvious.
The main challenge here is that the utility patent already issued.
It could have been possible to file a design patent application for the same product, if the design application was filed before the utility patent issued.