- ▸ Type II benzophenone-derivative photoinitiator used with amine synergists for surface cure of UV coatings (Coatings & Construction)
- ▸ Often blended with benzophenone as a liquid-friendly eutectic for UV/UV-LED inks (Industrial Manufacturing)
- ▸ Cures UV-curable plastics and adhesives in amine-synergist systems (Plastics & Polymers)
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
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4-Methylbenzophenone is a low-volatility Type II benzophenone-derivative photoinitiator. The methyl group lowers volatility and odor versus plain benzophenone while keeping benzophenone-style surface cure — used with an amine synergist. Identity: CAS 134-84-9.
What it is
4-Methylbenzophenone (CAS 134-84-9) is a methyl-substituted diaryl ketone. It is frequently blended with benzophenone as a lower-melting, lower-volatility liquid-friendly co-initiator package for UV surface cure.
How it cures
A Type II initiator: on UV excitation it abstracts a hydrogen from an amine co-initiator to form curing radicals. The methyl substituent mainly improves handling (lower volatility/odor, better solubility) rather than changing the mechanism. Pair with an amine synergist such as EDB or EHA.
Applications
Used for surface cure of UV coatings, overprint varnishes and inks where reduced volatility and odor are wanted, often co-blended with benzophenone and with a Type I initiator for through cure. Compare 4-chlorobenzophenone.
Forms, grades and handling
4-Methylbenzophenone is supplied as a low-melting solid / liquid-compatible grade. Photoinitiators are light-sensitive — store cool, dry and dark, away from light and ignition sources. Handle per the current Safety Data Sheet (SDS); each lot ships with a Certificate of Analysis (CoA) and Technical Data Sheet (TDS).
Bulk supply and RFQ
RawSource sources 4-Methylbenzophenone direct from producers in bulk, with CoA, TDS and SDS per lot. Tell us your lamp (mercury or LED wavelength), system (clear or pigmented) and cure target, and we will quote the right grade. Compare the full range and selection logic in the photoinitiators guide.
Typical Properties
Typical reference values, not a specification; the Certificate of Analysis (CoA) for the lot governs.
| Property | Typical Value |
|---|---|
| Chemical / type | Photoinitiator (Type II, benzophenone derivative) |
| Photoinitiator type | Type II (H-abstraction) |
| Absorption | UV (mercury-lamp range) |
| CAS Number | 134-84-9 |
| Molecular Formula | C14H12O |
| Molecular Weight | 196.24 g/mol |
| Handling | Light-sensitive; refer to the current SDS |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 205-159-1
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Frequently Asked Questions
What is 4-methylbenzophenone used for?
4-Methylbenzophenone (CAS 134-84-9) is a Type II photoinitiator for surface cure of UV coatings and inks, chosen for lower volatility and odor than benzophenone; it is used with an amine synergist.
How does 4-methylbenzophenone compare to benzophenone?
Both are Type II benzophenone-type initiators used with amine synergists; 4-methylbenzophenone has lower volatility and odor and better solubility, so the two are often co-blended.
How is bulk 4-methylbenzophenone supplied and quoted?
RawSource supplies 4-methylbenzophenone in bulk with CoA, TDS and SDS per lot. Pricing is quote-based on grade and volume; submit an RFQ with your target quantity.
What is the REACH and TSCA regulatory status of 4-Methylbenzophenone (MBZ)?
4-Methylbenzophenone (MBZ) (CAS 134-84-9) is subject to U.S. TSCA Inventory requirements; supplying it into the EU requires valid REACH registration ((EC) No 1907/2006). RawSource cannot verify a third-party supplier's registrations — buyers should require documented TSCA and REACH compliance for their jurisdiction and volume (EC 205-159-1).