MEKP Catalyst

Product Overview

MEKP is a widely used clear-to-pale yellow liquid peroxide, employed as the standard room-temperature initiator for curing unsaturated polyester and vinyl ester resins, including gelcoats 

Key Features & Benefits

• Versatile with a wide resin range: Efficiently cures orthophthalic, isophthalic, terephthalic, and vinyl ester systems

• Reliable cure control: Typically used at 1–2% dosage (by weight), delivering medium-to-high exotherm—ideal for laminating, molding, and tooling

• Buffered stability: Supplied as ~30–40% peroxide in phlegmatizers such as dimethyl phthalate for handling safety 

• Standard safety & performance: Has a flash point >75 °C and SADT (~65 °C), enabling safe storage and predictable performance 

Typical Usage

• General dosage: 1–2% MEKP with ~1% cobalt promoter (e.g., Co‑Oc) at 20–25 °C.

• Processes: Suitable for hand lay‑up, spray‑up, filament winding, RTM, tooling, structural panels, and centrifugal casting

Safety & Handling

• Hazards: Organic peroxide; flammable and explosive upon heating; causes skin/eye irritation; toxic by inhalation or ingestion

• Exposure Limit: ACGIH Ceiling STEL is 1.5 mg/m³ (0.2 ppm)

• Required PPE: Gloves, goggles, respirator in poorly ventilated areas

• First-Aid Considerations: In case of skin contact, flush with water; if inhaled, move to fresh air immediately

Storage & Shelf Life

• Optimal storage: Cool, dry area below 25–30 °C to avoid auto-decomposition and pressurised build-up

• Shelf life: Commonly ~6 months at 25 °C; degraded performance follows 

Environmental & Transport Data

• Biodegradable: Breaks down readily in water sludge systems but is ecotoxic to aquatic life at high concentrations

• Transport classification: UN 3105; Organic Peroxide Type D, Packing Group II