It will depend highly on the divergence of the IR laser and the power and also(at lower powers) the color of the balloon.
IIRC IR Lasers see Clear Balloons as opaque, so you should use clear ones(if this is wrong someone let me know).
Power output would need to be decently high, higher if the diode is multimode or has bad beam specs.
Why do you want to use an IR laser though?
just the difficulty of aiming an IR laser, make this a very iffy thing to attempt. I would recommend trying with a visible laser.
IIRC IR Lasers see Clear Balloons as opaque, so you should use clear ones(if this is wrong someone let me know).