There are other polyurea products on the market - just spend some time on google if there is something about polyurea that specifically appeals to you. Or see if you can contact the company direct like the other poster suggested.
As far as "non toxic", understand that the US Government requires all finishes to be non-toxic once cured. But even then the criteria for "non-toxic" are completely arbitrary. And I would add that some finishes can take a very long time to cure completely so technically they don't reach their "non toxic" state.
The upshot of all that is that what is safe to your animal is up to you. It's not just as simple as "non toxic".
As far as readily available products, there is Drylok Latex Waterproofer that is cheap and surprisingly durable. But it does leave a concrete like texture. You can also find bartop epoxy in small kits if you want a clear finish, but it is a lot more expensive and harder to work with.
If you truely need a gallon there are the epoxy paints made for concrete. These come in both solvent and waterborne versions and I have heard of both types being used with animals.
And there is also polyester resin. Not my favorite stuff to work with.
I have used waterborne urethane in cages for desert dwelling lizards. Super easy to work with but I can't say it would be my first choice if building a similar cage again.
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Currently keeping:
3.5.5 Gonyosoma oxycephalum (Javan, mixed colors)
0.0.3 Rhynchophis boulengeri
0.2 Lampropeltis triangulum multistriata
0.2 Lampropeltis triangulum gaigeae
0.0.3 Rhamphiophis rubropunctatus
1.1.1 Morelia viridis (Aru & Merauke locale types)
1.0 Morelia clastolepis
1.0 Rhodesian Ridgeback