Photoinitiators
Photoinitiator TPO
Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide
The industry benchmark acylphosphine oxide photoinitiator for deep, pigmented and UV LED curing.
Product Description
Photoinitiator TPO is a Type I acylphosphine oxide initiator that undergoes direct photolysis to generate two highly reactive radical species. Its absorption tail extending to approximately 420 nm makes it uniquely suited to pigmented systems and to modern UV LED curing units operating at 395–405 nm, where conventional alpha-hydroxy ketones show little response.
In white and colored coatings, TPO delivers true through-cure rather than surface cure only, preventing tacky underlayers and improving adhesion on wood, metal and plastic substrates. Typical use levels are 1–5 wt% alone, or 0.5–2 wt% in combination with ITX or amine synergists for balanced surface and depth cure.
Aolong TPO is produced under DCS-controlled synthesis with a strict impurity profile: assay ≥99.0% (HPLC), low acid value and low color ensure predictable reactivity and storage stability in sensitive acrylate formulations.
Key Features
- Long-wavelength absorption (up to ~420 nm) — ideal for UV LED 395–405 nm lines
- Outstanding through-cure in white, gray and heavily pigmented coatings
- Low yellowing and low odor formulations possible at optimized loadings
- Liquid TPO-L and powder TPO grades from one qualified source
Applications
- UV-curable wood, metal and plastic coatings
- White and pigmented UV inks (offset, flexo, screen)
- Structural UV adhesives and electronics encapsulants
- UV LED curing systems at 385–405 nm
- Photocurable 3D printing resins and dental materials
Specifications
| CAS No. | 75980-60-8 |
|---|---|
| Molecular Formula | C22H21O2P |
| Molecular Weight | 348.38 |
| Appearance | White to pale yellow crystalline powder |
| Assay (HPLC) | ≥ 99.0% |
| Melting Point | 91 – 94 °C |
| Acid Value | ≤ 1.0 mg KOH/g |
| Loss on Drying | ≤ 0.5% |
Packaging & Storage
25 kg fiber drum with PE liner, 1 kg aluminum-foil sample bag. Store cool, dry and protected from light; shelf life 24 months in original sealed packaging.
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