>>6382371gel instant cure glue (super glue)
plastic model use glue (plastic cement)
They probably mean any plastic cement you see on the market that contains styrene in it which is pretty much anything other than any of the "thin" cements. So something like pic related. I'm thinking that they soak the paper in the cement and wait for the solvent in the cement to evaporate, which leaves the styrene in the fibers of the paper, reinforcing it.