TPO Photoinitiator

TPO photoinitiator (CAS: 75980-60-8 ), also known as Irgacure TPO, lucirin TPO, is a high efficient Norish type I free radical photoinitiator, which is perhaps the most popular photoinitiators up to now. TPO is first developed by BASF company in 1990s. And they named it ‘Lucirin TPO’. It has excellent performance and is often used in combination with secondary amine and tertiary amine. It has been widely used in coatings, inks, adhesives, corrosion inhibitors, solders and other industries. Since 21st century, TPO initiator has been widely promoted and applied in the field of UV curing.

Mechanism of TPO to produce free radicals

The main reason that photoinitiators can set off the polymerization reaction is that upon absorbing UV light energy, they can produce active intermediate directly or indirectly, and the active intermediate is what initiate the polymerization and cured the paint, ink, or adhesive system.

When exposed to ultraviolet light, TPO photoinitiator molecular absorbs the energy and produces two free radicals – benzoyl and phosphoryl, both of which can initiate the polymerization. Therefore, enhance the photo-curing speed. Below figure shows the mechanism of TPO initiator creates two free radicals upon the absorption of photon.

photoinitiator tpo molecular homolytic cleavage
TPO photoinitiator produces 2 free radicals after UV irradiation

Applications of TPO Photoinitiator

TPO has a wide range of long UV wavelength absorption. Its effective absorption peak is 350nm ~ 400 nm, and absorbs all the way to 420 nm wavelength. Its absorption peak is longer than that of conventional initiator. Because of this, TPO photoinitiator is widely used in many applications, such as ultraviolet curing coatings, printing ink, ultraviolet curing adhesives, optical fiber coatings, etc. And because of its function of photobleaching, photoinitiator TPO is specially used in thick film and white systems. It can be completely cured on the pigmented surface of white or high titanium dioxide. TPO initiator can also be used for transparent coatings, especially for products with low odor requirements.

TPO is a medium and high-grade photocuring product, which is often recommended in the formulation of photo-curing ink, coating, adhesive with high added value. BoldChem produces TPO photoinitiator (CAS: 75980-60-8 ) in high quality with competitive price. Please contact us for more information.