Automotive Foam for Bus Seats

You should talk to some PU foam chemicals manufacturer they can guide you because they have to sell there product.

Polyurethane is what you get from a reaction between a diisocynate and a polyol,in the presence of catalyst and surfactants.They are used for everything from refrigeration insulation to seating.the reaction process determines how hard,soft or porous the foam ends up.

I dont think foam rubber is something you can make at home.