Trigonox 21S

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Organic peroxide

Organic peroxide

Trigonox 21S is an initiator for (co)polymerization of ethylene, styrene, acrylonitrile and (meth)acrylates. Curing agent for unsaturated polyester resins.

  • Product name

    Trigonox 21S
  • Chemical family

    Organic peroxide
  • CAS number

  • Physical form

  • Regional availability

    Africa, Asia, Asia Pacific, China, Europe, Global, India, Latin America, Middle East, North America, Oceania
  • Chemical name

    tert-Butyl peroxy-2-ethylhexanoate
  • Molecular Weight

  • Applications

    For polymer production: Polymerization of ethylene: Trigonox 21S is an efficient initiator for the production of Low Density Polyethylene (LDPE). It is used both for tubular and autoclave processes. In most cases a combination with other peroxides is used to ensure a broad reactivity range. Polymerization of styrene: in suspension polymerization processes, Trigonox 21S can be used for the polymerization of styrene at approximately 90°C. Trigonox 21 has an activity comparable with Dibenzoyl peroxide (Perkadox L-W75). Typically, Trigonox 21S is used in combination with initiators such as tert-Butyl peroxybenzoate (Trigonox C) and tert-Butylperoxy 2 ethylhexyl carbonate (Trigonox 117). For Thermoset: Trigonox 21S, tert-butyl peroxy 2 ethylhexanoate, is a perester which is used for the curing of unsaturated polyester resin at elevated and high temperatures. Trigonox 21S is preferred for the curing of UP resin based Hot Press Moulding formulation (such as SMC and BMC) in the temperature range of 120 - 160°C. As Trigonox 21S is a high reactive peroxide, it is very suitable as a kicker in formulations for pultrusion and SMC/BMC. In combination with a cobalt accelerator, Trigonox 21S is also applicable for the cure of UP resins in the temperature range of 60°C and higher. Application area can be air drying lacquers, diplacquers, wall panels, filament winding, etc.

Market Segments

Polymer production

Detailed description

Trigonox 21S is an initiator for (co)polymerization of ethylene, styrene, acrylonitrile acrylates and methacrylates.


  • Polymerization initiator


  • LDPE,
  • Polystyrene