Phaotoinitiator 819 CAS 162881-26-7

Item Name:
irgacure 819
omnirad 819
photoinitiator 819
CAS: 162881-26-7
MF: C26H27O3P
MW: 418.46
EINECS: 423-340-5


Phaotoinitiator 819, chemical name: Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide, well know as Irgacure 819, or Omnirad 819, is an efficient universal ultraviolet photoinitiator used to initiate UV polymerization reactions in unsaturated prepolymer systems. It can be used in UV-curable formulations for clear and for pigmented coatings on wood, metal, plastic, paper and optical fibers as well as for printing inks and prepregs.

BoldChem supplies high quality photoinitiator 819 (CAS No. 162881-26-7) with very competitive price.

Properties of Phaotoinitiator 819

Photoinitiator 819 is an acyl phosphine oxide type photoinitiator, whose photolysis produce has two trimethylbenzoyl groups and one phenylphosphonyl radical, both of which are highly active initiators. That enables 819 photoinitiator to have higher photoinitiating activity than Photoinitiator TPO.

UV spectrum of photoinitiator 819
UV spectrum of photoinitiator 819

Photoinitiator 819 has greater absorption in the ultraviolet and visible light regions. With absorption peaks at 338nm, 370nm, 405nm, and absorption wavelengths up to 450nm, it can more effectively initiate curing for coating systems containing pigments than other photoinitiators.

Photoinitiator 819 is pale yellow to yellow powder with below physical properties:

Density: 1.17 g/cm3
Flash Point: 310.6ºC
Melting Point: 131-135ºC
Boiling Point: 590ºC at 760 mmHg
Vapour Pressure: 6.78E-14mmHg at 25°C
Refractive Index: 1.588

819 Photoinitiator has sufficient solubility in active diluents and exhibits at low concentrations an outstanding curing performance in highly opaque white and colored furniture coatings or screen inks containing rutile titanium dioxide or colored pigments and affords minimum yellowing after exposure to sufficient amounts of UV radiation. Additionally the outstanding absorption properties of Photoinitiator 819 allow the curing of thick sections.

Strength of Phaotoinitiator 819

  • Low volatility, low odor, low yellowing, environment friendly.
  • High initiating activity and good solubility
  • Good for curing both white and dark UV curable formulation.
  • Good for curing thick and deep layer

Applications of Phaotoinitiator 819

Photoinitiator 819 has been widely used in industries such as coatings, inks, and adhesives due to its excellent performance. It can be used for curing thick film and pigmented systems, especially suitable for white systems and polyester/styrene systems reinforced with glass fibers.

Photoinitiator 819 hardly undergo yellowing after curing and under long-term light radiation, so it can be used in situations with strict yellowing requirements, such as white and light colored inks and paintings. In addition, Photoinitiator 819 has a bleaching effect on light, which can penetrate the coating and facilitate the thorough solidification of thick films.

Photoinitiator 819 can be used in conjunction with other photoinitiators, such as photoinitiator 184 or photoinitiator BDK. The combination of photoinitiator 819 and photoinitiator BDK is particularly suitable for curing  polyester/styrene resin systems, such as in glass fiber reinforced materials.

Due to its absorption in the long wavelength range, photoinitiator 819 can be used in combination with UV light absorbers, such as TINUVIN 400. Therefore, 819 photoinitiator can be applied to UV cured coatings that require weather resistance. When used in conjunction with light stabilizers, it can also be used for outdoor varnishes.

Packaging of Photoinitiator 819

Normally, 819 Photoinitiator is packed in 20 kg/cardboard drums, inner packed with PE bag, also can be packed according to customer requirements.

Photoinitiator 819 have no irritation to human skin, therefore, can be transported safely. No special safety measures are required, just follow the general chemical operation specifications.

Storage of Photoinitiator 819

Photoinitiator 819 should be sealed and stored in a dry, cool, dark place. It should be kept at low or room temperature to avoid sunlight and exposure to strong oxidants. 819 Photoinitiator has a shelf life of at least two years in a sealed container at 20°C in a dark ventilated place.