Dunno if that's PVC or hypalon, but there are special adhesives for most of these materials and the folks who sell the dinks sell them too. A hypalon adhesive/patch kit isn't cheap
, and has a limited storage
life once the glue is open.
You might try calling the people at "Amazing Goop"
their adhesives are mainly urethane based, sold as low-tech old fashioned products like "Shoe Goop" at non-marine prices, but the products themselves are quite modern and top quality. If you tell them what materials you are bonding, they'll tell you for certain if Goop will work. (It works on a number of products that everyone says "can't" be glued.)
Surface prep (cleaning and sanding) are crucial.