Methyl Cyanoacrylate, for metal bonding, and Ethyl Cyanoacrylate, for plastic and rubber bonding, are used principally in industrial applications. Octyl Cyanoacrylates and Butyl Cyanoacrylates are used principally in Medical Applications. Butyl esters provide stronger bond, but are rigid. Octyl ester, while providing weaker bond, are more flexible. Medical Adhesives need to be cause less sensitivity issues to skin.

Link: http://adteputek.com/b2evolution/blog2.php/2010/02/15/taking-into-consideration-the-substrates

When selecting an adhesive one needs to take into consideration the substrates surface energy as a factor in determining which adhesive is used and whether a primer is necessary. All metals have a high surface energy and thus are relatively easy to bond to. High Surface Energy Plastics include Kapton® (Polymide), Phenolic, Nylon, Alkyd Enamel, Polyester, Epoxy Paint,Polyurethane Paint, ABS, Polycarbonate, PVC (Polyvinyl Chloride), Noryl®, Acrylic, and Polane® Paint. I recently had a project for bonding to two small injection molded pieces made of pvc resin for a presentation laser pointer. I selected the Parfix 3422 Ethyl Cyanoacrylate, as a surface insensitive adhesive was not needed. Low surface Energy Plastics include PVA, Polystyrene, Acetal, EVA, Polyethylene, Polypropylene, Tedlar®, and Teflon®. These might include both a Surface Insensitive Adhesive and a Primer.