- ▸ Type II thioxanthone photoinitiator/sensitizer used with amine co-initiators for UV-curing pigmented coatings and inks (Coatings & Construction)
- ▸ Extends absorption to longer UV wavelengths for high-speed UV/UV-LED printing and overprint varnish (Industrial Manufacturing)
- ▸ Sensitizes through-cure of pigmented UV-cure plastics and adhesives (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 →ITX (CAS 5495-84-1) is 2-isopropylthioxanthone, a yellow powder (typically an isomer mixture). Identity: PubChem.
What it is
A Type II thioxanthone: under UV it reaches an excited state and abstracts a hydrogen from an amine co-initiator to form the curing radicals. Its long-UV absorption lets it cure through pigment and act as a sensitizer that boosts other initiators.
How it cures
ITX is a Type II thioxanthone photoinitiator/photosensitizer. It absorbs at longer UV wavelengths than most initiators, so it is excellent at curing pigmented systems — but as a Type II it works by hydrogen abstraction and requires an amine synergist.
Applications
ITX is used in pigmented UV inks and coatings, screen and offset inks, paired with an amine synergist such as EDB and often with an aminoketone (907). Compare the related DETX. Note: ITX migration is regulated in some food-contact applications — confirm suitability.
Forms, grades and handling
ITX is supplied as a yellow powder. 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 2-Isopropylthioxanthone 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 | 2-Isopropylthioxanthone — Photoinitiator (Type II, thioxanthone) |
| Type | Type II (H-abstraction), thioxanthone |
| Co-initiator | Requires an amine synergist |
| Absorption | Long UV — cures through pigment |
| Appearance | Yellow powder |
| CAS Number | 5495-84-1 |
| Molecular Formula | C16H14OS |
| Handling | Light-sensitive; refer to the current SDS |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 226-827-9
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Frequently Asked Questions
What is ITX used for?
ITX (2-isopropylthioxanthone, CAS 5495-84-1) is a Type II photoinitiator/sensitizer used in pigmented UV inks and coatings, paired with an amine synergist; its long-UV absorption helps cure through color.
Does ITX need an amine?
Yes — as a Type II initiator it cures by hydrogen abstraction and needs an amine synergist (such as EDB or EHA) to generate radicals.
What is the difference between ITX and DETX?
Both are Type II thioxanthones used with amine synergists; they differ in substitution (isopropyl vs diethyl), solubility and absorption fine-tuning. DETX is often chosen for solubility and slightly different spectral fit.
Is ITX restricted in food packaging?
ITX migration has been a concern in some food-contact printing; confirm regulatory suitability and consider low-migration alternatives for food packaging.
How is bulk ITX supplied and quoted?
RawSource supplies it as a powder 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 2-Isopropylthioxanthone (ITX)?
2-Isopropylthioxanthone (ITX) (CAS 5495-84-1) 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 226-827-9).