Create an artboard in the pixel dimensions you want to export, so it's not necessary to resample on export (by setting a higher ppi than 72 e.g.)
You have to be careful with matching the artboard to the pixel grid.
In this artboard you create your pattern. Use the pattern editing mode as you please.
If your pattern is smaller than that artboard, the artboard will need to be a multiple of the pattern, so that everything matches.
What is important is working aligned to the pixel grid.
When exporting check "Artwork optimized" for the antialiasing.
When exporting a PNG, depending on your version there might still appear transparent edges around the image. You will need to crop them in Photoshop.
Work in Pixels.
When you export as an image, you will use pixels, so make your Illustrator units also pixels.
Don’t use fractional pixels and make sure that the artboard is aligned to the pixel grid (top left corner X:0 and Y:0)
Export only the pattern tile at a resolution that is a multiple of 72 ppi.
Thank you! I will try that.
Thanks! I’m going to try that.