Protective Coat?

Im in the process of making a gift for my DND group. I got some dice trays with a velvet lining and used some HTV to apply their charact names onto them.

My main worry is that while they are good now, having dice rolled on the vinyl may cause them to scratch and break. Does anyone know of some kind of spray, like a varnish or fixative that could be sprayed over the vinyl and velvet that would supply some small lever of protection?

Thanks in advance.