QUESTION: We have a patent in China but did not make the PTC within 12 months.
We got a utility patent in China in 2015 for our invention. However before all test where done we did not make the deadline of the 12 months to go for a PTC. Now we made modifications to our invention that is a significant improvement. Questions : 1. How should we apply for a modification of the original patent? 2. Can we go for a PTC if the modification of our patent is approved? 3. Is there any other way to get the patent international even we missed the deadline of 12 months?

ANSWER: If you file a PCT application within 12 months of filing a “national” application (e.g., China), you can claim “priority” to the national application. Once your national application issues as a patent, it becomes prior art to your newly filed patent applications (e.g., PCT or other).

If your newly filed patent application is not “obvious” in view of your issued Chinese patent, you can still get a patent but you will not be able to claim priority based on your Chinese patent.