Not all paintings done in acrylic are meant to be framed. A popular choice for painting floor cloths is with acrylic paint. These too require a coating for protection.
My first choice for finishing floor cloths is now DuraClear by DecoArt varnish. It dries clear, is flexible, and the floor cloth lays flat once it is dried.
I didn't know that about varnishes for acrylic when I first started painting floor cloths. Some of the finishes made the edges turn, even though they were hemmed (edges folded under and glued down on the underside.)
I know if you're painting floor cloths, you'll want the edges to lay flat. (Also add carpet backing to keep it more stationary.)
The art varnishes also come in Interior and Exterior/Interior options.
The floor cloth that I painted years ago is still laying on our dining room floor.