Spray foam insulation that we use is Heatlok soya, a 2lb closed cell foam that can be applied to virtually any material except for poly, spray foam insulation will only separate from poly because of the porous material and the oils on the plastic.  This is why we use plastic sheathing to cover windows and floors to cover them from spray foam overspray.  As well overspray on vehicles can be harmful to the paint on the vehicles when spray foam overspray’s due to wind when spraying outside.