Overview
This general purpose methyl ethyl ketone peroxide (MEKP) is used for the curing of unsaturated polyester resins in the presence of a cobalt accelerator at room and elevated temperatures. This grade offers all the advantages of a standard MEKP such as Butanox M-50, with the addition of a vanishing red indicator system that virtually disappears during cure. This page summarizes the published specifications for this grade and outlines what buyers should consider before sourcing it.
Specifications
| Appearance, 20-25°C | Red liquid |
| Total active oxygen | 8.8-9.0% |
Characteristics
| Density, 20°C | 1.180 g/cm³ |
| Viscosity, 20°C | 24 mPa.s |
Applications of Butanox M-50 VR Across Market Segments
It is used for the curing of unsaturated polyester resins in the presence of a cobalt accelerator at room and elevated temperatures, matching the general purpose curing performance of standard Butanox M-50. The red color is present when needed, during the mixing step, but will disappear during cure, giving fabricators a visual reference for mixing consistency across gelcoat and laminating applications.
Why the Vanishing Red Indicator Matters for Mixing Quality Control
Because this grade includes a vanishing red indicator system, fabricators gain a visible way to confirm that the peroxide has been mixed into the resin during the mixing step, since the red color is there when needed and then disappears during cure. This can be a practical quality control aid for operators checking mixing uniformity before a part is laid up, without changing the underlying curing chemistry compared to standard Butanox M-50.
Why Sourcing Consistency Matters for Buyers
Because this grade offers all the advantages of a standard MEKP while adding the vanishing red indicator, lot-to-lot consistency in total active oxygen content remains the primary driver of cure repeatability. A supplier that consistently delivers Butanox M-50 VR within its stated 8.8-9.0% total active oxygen range and 1.180 g/cm³ density reduces the need to re-tune cobalt accelerator loading with every new batch.
This is particularly relevant for fabricators running scheduled gelcoat or laminating production, where a batch outside specification can shift gel time and affect part quality regardless of whether the vanishing red indicator is present. Reviewing the certificate of analysis for active oxygen content, density, and viscosity before a batch enters production is a reasonable quality check.
What to Consider When Sourcing Butanox M-50 VR
Buyers already familiar with standard Butanox M-50 should note that this grade is positioned to offer the same curing performance with the added benefit of the vanishing red mixing indicator, rather than a different reactivity profile. Requesting the current certificate of analysis alongside the safety data sheet is a practical way to confirm that a given batch matches the appearance, active oxygen, density, and viscosity specifications listed above.
Because the red color is a visual mixing aid rather than a performance specification, buyers should confirm with their supplier how the indicator behaves under their specific resin system and cobalt accelerator loading before relying on it as a process control step. Packaging, storage temperature, and transport classification should also be confirmed given the regulatory requirements around organic peroxides.
General Handling and Storage Guidance
As with other organic peroxides, this product should be stored in accordance with the supplier’s safety data sheet, typically in a cool, dry, well-ventilated area away from direct sunlight, incompatible materials, and sources of heat or ignition. Personnel handling this product should follow the personal protective equipment and handling procedures specified in the SDS, since organic peroxides can decompose exothermically under certain storage or contamination conditions.
Buyers should request and review the current safety data sheet prior to receipt, and confirm that on-site storage conditions, including temperature control, are compatible with the recommended storage requirements for this grade. Proper inventory rotation and adherence to the stated shelf life help maintain the active oxygen content and curing performance described above.
Where to Source This Product
Chemicalsstore.com provides supply chain resource support for Butanox M-50 VR and related organic peroxide grades used in unsaturated polyester resin curing. Buyers can review our broader organic peroxide product range for related curing systems. For general reference on peroxide classification and safe handling practices, buyers can also consult resources such as the ASTM International standards library.
Documentation We Can Provide
For qualified buyers, we can provide the safety data sheet and, where available, a certificate of analysis for the specific batch of Butanox M-50 VR being quoted. Specifications listed on this page reflect the manufacturer’s published values; buyers should confirm current documentation before finalizing a purchase order.
FAQ
What is Butanox M-50 VR used for?
Butanox M-50 VR is used for curing unsaturated polyester resins in the presence of a cobalt accelerator at room and elevated temperatures, offering the same performance as standard Butanox M-50.
What does the VR in Butanox M-50 VR stand for?
VR stands for vanishing red, an indicator system where the red color is present during mixing and disappears during cure.
What is the active oxygen content of Butanox M-50 VR?
Butanox M-50 VR has a published total active oxygen content of 8.8-9.0%.
Is Butanox M-50 VR different from standard Butanox M-50 in performance?
No. Butanox M-50 VR offers all the advantages of a standard MEKP such as Butanox M-50, with the addition of the vanishing red mixing indicator.
Get a Quote for Butanox M-50 VR
Contact our team for pricing, documentation, and lead time on Butanox M-50 VR. Our sourcing specialists can help confirm whether this vanishing red MEKP matches your curing process before you place an order.
