Anyone know the cutoff time for international checked bags at SFO? On UA's web site, it says 2 hours but I'm not sure if this is a cutoff or a recommended time.

Assuming 2 hours is a cutoff, what if I check my bags and then leave the airport to go have lunch with my SO. Is 45 min enough time to make it through security and to my flight to TPE? This is a Sunday afternoon.

Thanks for any tips. I'm new to SFO and UA, so I'm not sure what to expect.