Para-tert-octylphenol Para-tert-octylphenol 140-66-9 Schenectady International Tackifier >> Alkylphenolic PARA-tert-OCTYLPHENOL (PTOP) Surfactants, Tackifier Resins, Ink Resins, Polycarbonate Chain Terminator, Ultraviolet Stabilizers Para-tert-octylphenol (PTOP). Used as a tackifier resin.