I just realized in my previous post I did not offer the reason I made the recommendation. Good spray-on repellents can work but all depends on the fabric you are spraying it on. Repellents protect the fiber itself but you still have to consider the space between the fibers, which repellents have no effect on. So, if the fabric is relatively porous, you might protect the fabric from penetrating the fibers, but not between the fibers. If the fabric is pretty dense, your repellent might provide better coverage. Some industrial aprons are lined with cotton duck to provide better coverage, yet breathability. I'm not sure exactly what the intended purpose of your apron will be. Metal casters, for example, often use leather aprons, which provide some breathability, flexibility, less penetrability and more safety protection.
Cheers and hope you find something that will work for you! Renata