I took time off for interviews; typically a full day for onsites and half a day for phone tech screens. If they're open to early morning or evening phone screens, you could suggest that too.

I would typically take the initial HR call in my car at lunch (drive to a nearby parking lot if you're worried about your current company seeing you). You could try to do this with tech screens as well, but I would make sure you have a rock solid internet connection and a good laptop. I never felt comfortable with that, so I just booked the morning off and did it at home.