A 180x180px image is quite small, and you will lose detail when outputting images at that size, particularly if some of the details are already small/fine.
You could try this and see if it helps: Export it at a larger size from Illustrator, then use Photoshop to rescale the image using Bicubic Sharper (best for reduction), or if you don't have access to Photoshop, GIMP has a Sinc(Lanczos 3) interpolation method for rescaling/resampling.
Raster image editors will give you more control when rescaling images. These interpolation methods help to a degree by sharpening to the images to keep small details visible. However, ultimately if you make images small that have fine detail, your will lose some detail. That's to be expected. You should try to avoid that when designing logos so that the problem doesn't arise, so that they look good at any scale.