P.S.: The trip will last for 6 months, is there any problem for staying that long outside Canada? Thank you !
Your PR card is your permission to re-enter Canada as you are now a legal resident. You will also need your passport. Staying out of Canada for 6 months is not a problem as long as you satisfy the residency requirement that pinklady mentioned. That 2 years does not have to be continuous but it must total 2 years (730 days) in the 5 year period.