- ▸ Type I alpha-hydroxyketone photoinitiator giving low-yellowing cure of clear UV coatings, lacquers and overprint varnish (Coatings & Construction)
- ▸ Standard initiator for clear UV/UV-LED inks and high-gloss line coatings (Industrial Manufacturing)
- ▸ Cures clear UV-curable adhesives, hardcoats and plastics (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.
Request SDS →This photoinitiator (CAS 947-19-3) is 1-hydroxycyclohexyl phenyl ketone, a white-to-off-white crystalline solid. Identity: PubChem.
What it is
A Type I α-hydroxyketone that cleaves under UV (mercury-lamp range) into radicals. It excels at surface cure with very low yellowing and low odor, and is non-yellowing in clear films — the standard choice for clear coatings and overprint varnishes.
How it cures
This photoinitiator is a Type I α-hydroxyketone — the benchmark for clean, low-odor, low-yellowing surface cure of clear UV systems. It cleaves under UV to radicals and is prized for color stability and minimal residual odor.
Applications
It is the workhorse surface-cure initiator for clear coatings, overprint varnishes, clear inks and adhesives. It is almost always blended with a deep-curing acylphosphine oxide such as TPO (and sometimes the liquid 2-hydroxy-2-methylpropiophenone) to combine surface and through cure.
Forms, grades and handling
This photoinitiator is supplied as a white crystalline powder/granule. Photoinitiators are light-sensitive — store cool and dark. Many are fine powders or liquids that require dust/handling controls 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 this photoinitiator 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 or blend. 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 | 1-Hydroxycyclohexyl phenyl ketone — Photoinitiator (Type I, hydroxyketone) |
| Type | Type I (cleavage), α-hydroxyketone |
| Cure | Surface cure; low odor; non-yellowing |
| Absorption | UV (mercury-lamp range) |
| Appearance | White crystalline solid |
| CAS Number | 947-19-3 |
| Molecular Formula | C13H16O2 |
| Handling | Light-sensitive; refer to the current SDS |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 213-426-9
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Frequently Asked Questions
What is 1-hydroxycyclohexyl phenyl ketone used for?
1-Hydroxycyclohexyl phenyl ketone (CAS 947-19-3) is a Type I hydroxyketone used for clean, low-yellowing surface cure of clear UV coatings, varnishes, inks and adhesives, usually blended with TPO for through cure.
Is this photoinitiator yellowing?
No — it is a non-yellowing, low-odor surface-cure initiator, which is why it is the standard for clear coatings and overprint varnishes.
What is the difference between 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methylpropiophenone?
Both are Type I α-hydroxyketones; 1-hydroxycyclohexyl phenyl ketone is a solid and 2-hydroxy-2-methylpropiophenone is a liquid. 1-Hydroxycyclohexyl phenyl ketone is favored where a solid and slightly lower odor are wanted; 2-hydroxy-2-methylpropiophenone where a liquid is easier to handle.
Does this photoinitiator work alone?
It cures the surface well alone but is typically paired with an acylphosphine oxide (TPO/BAPO) for deep/through cure, especially in thicker or pigmented films.
How is this photoinitiator supplied and quoted in bulk?
RawSource supplies it as a powder/granule in bulk with CoA, TDS and SDS. Pricing is quote-based on grade and volume; submit an RFQ.
What is the REACH and TSCA regulatory status of 1-Hydroxycyclohexyl Phenyl Ketone?
1-Hydroxycyclohexyl Phenyl Ketone (CAS 947-19-3) 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 213-426-9).