Perovion TBPEH L21 is a liquid organic peroxide, tert-butyl peroxy-2-ethylhexanoate (TBPEH), used as an initiator for the polymerization of ethylene, styrene, acrylonitrile, and methacrylates and acrylates, as well as a curing agent for unsaturated polyester resins. Perovion TBPEH L21 is a preferred initiator for curing UP resin-based hot press molding formulations such as sheet molding compound (SMC) and bulk molding compound (BMC) in the 120-160°C temperature range.
Perovion TBPEH L21 Overview
As a medium-temperature peroxyester, Perovion TBPEH L21 decomposes at a rate suited to compression molding cycles, giving compounders a workable open time for charge preparation and mold filling before an efficient cure sets in once the mold reaches temperature, which supports consistent part quality across a full production shift and reduces the need for frequent process adjustments between batches. Its liquid form at room temperature simplifies metering into resin paste formulations compared to solid peroxide grades. This also reduces the risk of uneven initiator distribution that can sometimes occur when blending solid peroxides into viscous resin pastes, supporting more uniform cure throughout the molded part.
Formulators new to this chemistry should note that dosage, mold temperature, and press cycle time all interact to determine cure state and part quality. Working with a supplier that can advise on typical dosage ranges for a given SMC or BMC formulation helps shorten the qualification process when introducing this grade into an existing molding line.
The 120-160°C decomposition profile of this peroxyester sits between faster room-temperature curing peroxides and slower high-temperature grades, which is why it is so commonly specified for compression molding processes where the compound must survive handling and mold-charging at ambient temperature before curing rapidly once the heated mold closes.
Key Features
- Medium-temperature cure profile: Suited to hot press molding cycles in the 120-160°C range, giving a practical balance between open time and cure speed.
- Broad initiator applications: Suitable for polymerization of ethylene, styrene, acrylonitrile, and (meth)acrylates, in addition to UP resin curing.
- Liquid handling convenience: Supplied as a clear liquid, simplifying metering and blending into resin paste compared to solid peroxide grades.
- Established SMC/BMC fit: Long-standing use in compression molding of glass-reinforced composite parts means well-documented dosing practices are available.
- Temperature-controlled shipping and storage: Classified for temperature-controlled transport and storage, supporting predictable shelf life when handled correctly.
Typical Applications
Perovion TBPEH L21 is widely used in sheet molding compound (SMC) and bulk molding compound (BMC) formulations for compression-molded composite parts, including automotive body panels, electrical housings, and other glass-fiber-reinforced components requiring a well-controlled hot press cure. It also serves as an initiator in ethylene, styrene, acrylonitrile, and (meth)acrylate polymerization processes.
Compounders producing SMC and BMC value the balance this grade provides between shelf stability of the uncured compound and efficient cure once the mold reaches operating temperature, which supports consistent cycle times across a production run and helps minimize scrap from under- or over-cured parts. This predictability is particularly valued in automotive and electrical component manufacturing, where dimensional stability and consistent mechanical properties are critical quality requirements that directly affect part acceptance rates.
Beyond SMC and BMC, this peroxide chemistry is also used more broadly in the polymer industry as an initiator for suspension and bulk polymerization of ethylene, styrene, acrylonitrile, and various methacrylate and acrylate monomers, where its mid-range decomposition temperature supports efficient reactor operation without requiring extreme process temperatures, helping producers balance reaction rate against energy consumption while still achieving the desired molecular weight, conversion, and gel-content targets that downstream fabricators rely on for consistent part performance.
Technical Specifications
- Chemical Type: tert-Butyl peroxy-2-ethylhexanoate (TBPEH)
- CAS Number: 3006-82-4
- Appearance: Clear liquid
- Density at 20°C: Approximately 0.900 g/cm³
- Active Content: To be confirmed based on the final specification sheet.
- Total Active Oxygen: To be confirmed based on the final specification sheet.
Thermal Stability
- Organic peroxides are thermally unstable substances and must be handled with appropriate care.
- SADT: To be confirmed based on the final specification sheet.
Storage Recommendations
- Recommended storage temperature: -30°C to 20°C (temperature-controlled) to prevent crystallization
- Store in a dry, well-ventilated area away from heat sources and direct sunlight.
- Keep containers tightly closed.
- Avoid contact with reducing agents, acids, alkalis, and heavy metal compounds.
- When stored within the recommended temperature range, this product remains within specification for approximately three months after delivery.
Packaging & Transport
- Standard Packaging: 30 L HDPE container (vented), approximately 25 kg peroxide content; regional pack sizes may vary
- Net Weight: To be confirmed based on the final specification sheet.
- UN Number: UN 3113
- Transport Class: Organic peroxide, Type C, liquid, temperature controlled, Division 5.2, Packing Group II
Facilities running mixed SMC, BMC, and polymer production lines often value having a single, well-documented peroxyester grade that can support multiple process types, which can reduce the complexity and cost of qualifying separate initiators for each application. First-in, first-out stock rotation and dating of containers on receipt are recommended, particularly given the temperature-controlled storage requirement for this product, which calls for dedicated refrigerated storage capacity in most facilities.
Perovion TBPEH L21: Safety & Handling
Perovion TBPEH L21 should be handled in accordance with applicable safety procedures for organic peroxides. The product is classified as an oxidizing material and requires appropriate storage and handling measures, including keeping it segregated from reducing agents, accelerators, and other incompatible substances. Facility operators should also maintain adequate ventilation, avoid confined storage areas, and ensure that fire suppression equipment rated for organic peroxide incidents is readily accessible near any bulk storage location, and confirm that emergency response contacts are posted at the storage site.
Users, particularly those new to handling temperature-sensitive liquid peroxides, are advised to review the Safety Data Sheet carefully prior to handling and to implement appropriate personal protective equipment and engineering controls as specified therein, including measures to maintain the product within its recommended temperature range during transfer and dosing. Safety Data Sheet and destination-compliant labeling information are available upon request, and should be reviewed by all personnel before first use at a new site. For related peroxyester initiators, see also Perovion TBPB LC and Perovion TAEH L12-80.