On delay AC recepticale

In our area, the electrical utility experiences frequent outages. The power will go out, then back on for a few seconds, then off, etc.
I have provided back-up power for my computer equipment, but when I am out-of-town, sometimes the power will stay off until the back-up units are depeleted. The only unit that gives me trouble is my router. I have found that I can minimize the problem if I can delay the power from coming on for a minute or so Is there an on delay device on the market (not too expensive) that will delay the re-establishment of the 110 VAC for a minute or so when power is re-established?