Polyurethane is a possible suitable material for both forming a
negative mould and using that to cast new mats.  There are a wide range
of polyurethanes suitable for the finished product.  Polyurethane is
very abrasion resistant.  Currently, I am trying to repair polyurethane
inflatable tank seals used in winery operations, hence my interest in
this material.

Regards from Melbourne, Oz.
Paul Rumpf