October 19, 2022 Longchang Chemical

Photoinitiator 819 CAS 162881-26-7


Photoinitiators are an essential component in UV-LED curing materials and play a significant part in influencing the rate at which photocurable materials cure. Thus, photoinitiators in the 385nm or 395nm wavelength range that have high absorption intensity, high activity, shallow colour, no yellowing, good solubility, and low toxicity are the primary focus of research and development at this time.

What is IRGACURE 819?

In practically all of today’s photocuring systems, an ultraviolet (UV) photoinitiator is the kind of light source that is utilised. An example of an acylphosphine oxide photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, to give it its full chemical name. Irgacure 819 also falls under this category. Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is one of the chemical substances that are appropriate for the purpose of inquiry. Unsaturated resins are more likely to undergo radical polymerization when the very versatile photoinitiator IRGACURE 819 is subjected to ultraviolet light. It is utilised in the manufacturing of white pigmented formulations, the curing of glass fibre reinforced polyester/styrene systems, and the formulation of clearcoats for outdoor usage in conjunction with light stabilisers. Large quantities of material can be cured with the help of this photoinitiator if necessary.

Because the photoinitiator Irgacure 819 is non-toxic to human bodies, as needed by global food safety regulations, it is appropriate for use in UVLED curing varnish or ink as well as other light-curing goods. This makes it compliant with global food safety legislation. In addition to that, it is compatible with UVLED varnish and ink for curing.

Irgacure 819 is a fundamental component of UV-curing materials and plays an important part in the process of adjusting the rate at which these substances harden when they are exposed to light. After being exposed to light, the substance known as Irgacure 819 goes through a photochemical transition, which leads to the production of reactive intermediates (free radicals or cations) that can initiate the polymerization reaction.

Applications of Irgacure 819

IRGACURE 819 can be utilised in printing inks and prepregs, in addition to clear and coloured coatings on wood, metal, plastic, paper, and optical fibres in UV curable formulations once it has passed the necessary tests. These coatings can be applied using UV light. After the UV curing procedure is complete, these coatings can then be applied.

Curing Abilities of IRGACURE 819

IRGACURE 819 exhibits remarkable curing efficiency at low concentrations in very opaque white and coloured furniture coatings or screen inks including rutile titanium dioxide or coloured pigments, without yellowing even after being exposed to high levels of UV light. This is the case even though the coatings and inks contain these components. Titanium dioxide, in its rutile form, is occasionally utilised in the production of coatings and inks. In addition, the excellent absorption qualities of IRGACURE 819 make it possible to cure components that have a thicker consistency. Other photoinitiators, such as IRGACURE 184 or IRGACURE 651, can be used in with IRGACURE 819 to provide a synergistic effect. The latter is typically utilised to cure polyester/styrene resins, which are typically utilised to cure glass-reinforced products, whilst the former is well suited for this purpose and is commonly utilised for the curing of glass-reinforced products. IRGACURE 819 is photosensitive at longer wavelengths than UV absorbers such as TINUVIN 400, which means that the two can be used together with very little interference from one another. As a consequence of this, it is an excellent material for use in coatings that can be cured by UV light and is waterproof. It is advisable to do a series of experiments with varying concentrations in order to establish the right dose of IRGACURE 819 for a specific application.

In radical polymerization of unsaturated resins

Irgacure 819 is a photoinitiator that, when subjected to ultraviolet light, encourages the radical polymerization of unsaturated resins. It has a high degree of adjustability. It is particularly helpful for the development of white pigmented formulations, the curing of glass-fiber-reinforced polyester/styrene systems, and the production of transparent coatings for outdoor usage in conjunction with light stabilisers. The utilisation of this photoinitiator makes it possible to cure even thick areas of the material.

For  clear colored coatings

Irgacure 819 is utilised in UV-curable formulations for clear and coloured coatings on wood, metal, plastic, paper, and optical fibres, in addition to printing inks and prepregs. These coatings can be applied to a variety of substrates, including: wood, metal, plastic, paper, and optical fibres. Plastic, paper, and even optical fibres are all included in this category. This product demonstrates remarkable curing ability at low concentrations in extremely opaque white and coloured furniture coatings or screen inks employing rutile titanium dioxide or coloured pigments. It also permits minimal yellowing after enough exposure to UV light. Additionally, opaque white and coloured furniture finishes benefit the least from the delayed drying capabilities of this solution. This is especially true for coloured finishes. Because it has such a high capacity for absorption, Irgacure 819 may be used to cure even thick sections of material.

Irgacure 819, more generally referred to as IRGACURE 819, is a pigment that can be cured with UV light and is suitable for use in coatings for coloured plastic. UV coatings are popularly employed in the plastic housings of a wide variety of electronic and home appliance products because of their superior performance and the ease with which they can be manufactured. On the other hand, UV coatings are applied to the coloured plastic housing following the colouring process. Inadequate curing has a substantial impact on the appearance of the coating film because it leads to inadequate adherence of the coating film and inadequate pigment dispersion by the UV resin. Both of these issues are caused by inadequate curing. Because of this, the standard method of construction calls for first priming the surface with a coloured, solvent-based primer before baking the surface. This step is followed by baking the surface. First apply a UV varnish in order to improve the paint film’s surface so that its physical attributes are more desirable, and then apply the varnish.

Summary of Irgacure 819 Utilisability

  1. UV-curable coatings and inks are those that can be hardened by exposure to ultraviolet light.
  2. Photoinitiator 819 is a very potent and versatile UV photoinitiator that may be used to initiate the polymerization of unsaturated prepolymerization systems by making use of UV light. This can be accomplished by using the photoinitiator in combination with UV light.printing inks and various pre-treatment methods for a variety of surfaces, including wood, metal, plastic, paper, and fibres.
  3. Irgacure 819 It is possible to produce a coating that has superior curing effects and durability by adding a small amount of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide to white paints, coloured paints, or inks containing titanium dioxide or other pigments with strong hiding power. This can be done with white paints, coloured paints, or inks. This is the case regardless of whether the coating is dark in colour, light in colour, or coloured. The yellowing that comes from exposure to UV light.
  4. The material 819 is suitable for application in thick film systems as a result of the remarkable absorption qualities that it possesses.
  5. Other photoinitiators, such as 184 or 651, may be utilised in conjunction with Irgacure 819 throughout the execution of the curing process.
  6. The curing of polyester/styrene resin systems, such as those used in glass fibre reinforced composites, is an application where the combined use of Irgacure 819 and 651 is very favourable. This is one of the applications where the combination of Irgacure 819 and 651 is particularly advantageous.
  7. Irgacure 819 can be used in UV curable coatings that require weather resistance because of its capacity to absorb in the long wave band. This property allows it to be used in these coatings. Because of this, it can be utilised in UV curable coatings in conjunction with UV absorbers like TINUVIN 400.

Precautions to be followed while Irgacure 819 usage

In order to maintain compliance with good manufacturing practise (GMP), it is imperative that IRGACURE 819 be handled appropriately at all times. The SDS is the document in which you will discover all of the essential particulars. Because IRGACURE 819 is photosensitive, you must exercise extreme caution while working with it in any setting where there is exposure to sunlight or any other kind of visible light source. When you are finished using a drum that has been opened, make sure that the lid is replaced so that the contents are protected from air and light.

Recommended Dosages

  • Coatings composed of clear acrylic and unsaturated polyester/styrene in concentrations ranging from 0.1 to 0.2% IRGACURE819 1 – 2% IRGACURE184
  • Coatings ranging from 0.5 to 1% made of white acrylic and unsaturated polyester/styrene IRGACURE819 1 – 2% IRGACURE184
  • Formula for coloured acrylics ranging from 0.5 to 1% IRGACURE819 1 – 2% IRGACURE184
  • Ink for white screen printing that ranges from 0.5 to 1.5% IRGACURE819 1 – 2% IRGACURE184
  • Glass fibre reinforced unsaturated polyester/styrene prepreg 0.1 – 0.2% IRGACURE819


Irgacure 819, also known as Phenylbis(2,4,6-trimethylbenzoyl)phosphineoxide, is a potent and versatile UV photoinitiator that is used in the process of initiating the polymerization of unsaturated prepolymerization systems by making use of ultraviolet light. This process is known as the process of initiating the polymerization of unsaturated prepolymerization systems. Because it is present, curing processes for thick film systems, notably white systems and the glass-reinforced polyester/styrene system, are simplified as a result. It is also possible for it to fulfil the role of an outdoor varnish if it is coupled with light stabilisers and applied in the suitable manner. Investigations exploring the application of Irgacure 819 with printing inks and prepreg systems on a wide variety of materials, such as paper, wood, metal, and plastic, have been carried out. When a small amount of Irgacure 819 is added to high-opacity white paints, paints, or inks that contain titanium white or other pigments, the resulting coating will have outstanding cure and UV yellowing resistance. As a result of the extraordinary absorption characteristics it boasts, Irgacure 819 is an excellent choice for use in applications involving thick film.

There is a large variety of photoinitiators, such as IRGACURE 184 and IRGACURE 651, that are compatible with Irgacure 819. The combination of Irgacure 819 and Irgacure 651 is perfectly suited for curing polyester/styrene resin systems, such as those used in glass fibre reinforced composites. These resins are typically utilised in the manufacturing of glass fibre reinforced composites. This is because of the high concentration of styrene found in each of these chemicals, which is the cause of the problem. Because it is compatible with an ultraviolet light absorber such as TINUVIN 400, the photoinitiator 819 can be used in a UV curable coating that needs to have weather resistance. This is because the coating needs to be cured using ultraviolet light. Irgacure 819 is one type of material that can absorb ultraviolet light and is an example of this type of absorber. Even if the yellow phase only occurs for a very short period of time during the curing process, it is still of great use to the photobleaching process in the long run.


Same series products

Product name CAS NO. Chemical name
Sinocure® TPO 75980-60-8 Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide
Sinocure® TPO-L 84434-11-7 Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate
Sinocure® 819/920 162881-26-7 Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide
Sinocure® 819 DW 162881-26-7 Irgacure 819 DW
Sinocure® ITX 5495-84-1 2-Isopropylthioxanthone
Sinocure® DETX 82799-44-8 2,4-Diethyl-9H-thioxanthen-9-one
Sinocure® BDK/651 24650-42-8 2,2-Dimethoxy-2-phenylacetophenone
Sinocure® 907 71868-10-5 2-Methyl-4′-(methylthio)-2-morpholinopropiophenone
Sinocure® 184 947-19-3 1-Hydroxycyclohexyl phenyl ketone
Sinocure® MBF 15206-55-0 Methyl benzoylformate
Sinocure® 150 163702-01-0 Benzene, (1-methylethenyl)-, homopolymer,ar-(2-hydroxy-2-methyl-1-oxopropyl) derivs
Sinocure® 160 71868-15-0 Difunctional alpha hydroxy ketone
Sinocure® 1173 7473-98-5 2-Hydroxy-2-methylpropiophenone
Sinocure® EMK 90-93-7 4,4′-Bis(diethylamino) benzophenone
Sinocure® PBZ 2128-93-0 4-Benzoylbiphenyl
Sinocure® OMBB/MBB 606-28-0 Methyl 2-benzoylbenzoate
Sinocure® BP 119-61-9 Benzophenone
Sinocure® 754 211510-16-6 Benzeneacetic acid, alpha-oxo-, Oxydi-2,1-ethanediyl ester
Sinocure® CBP 134-85-0 4-Chlorobenzophenone
Sinocure® MBP 134-84-9 4-Methylbenzophenone
Sinocure® EHA 21245-02-3 2-Ethylhexyl 4-dimethylaminobenzoate
Sinocure® DMB 2208-05-1 2-(Dimethylamino)ethyl benzoate
Sinocure® EDB 10287-53-3 Ethyl 4-dimethylaminobenzoate
Sinocure® 250 344562-80-7 (4-Methylphenyl) [4-(2-methylpropyl)phenyl] iodoniumhexafluorophosphate
Sinocure® 369 119313-12-1 2-Benzyl-2-(dimethylamino)-4′-morpholinobutyrophenone
Sinocure® 379 119344-86-4 1-Butanone, 2-(dimethylamino)-2-(4-methylphenyl)methyl-1-4-(4-morpholinyl)phenyl-
Sinocure® 938 61358-25-6 Bis(4-tert-butylphenyl)iodonium hexafluorophosphate
Sinocure® 6992 MX 75482-18-7 & 74227-35-3 Cationic Photoinitiator UVI-6992
Sinocure® 6992 68156-13-8 Diphenyl(4-phenylthio)phenylsufonium hexafluorophosphate
Sinocure® 6993-S 71449-78-0 & 89452-37-9 Mixed type triarylsulfonium hexafluoroantimonate salts
Sinocure® 6993-P 71449-78-0 4-Thiophenyl phenyl diphenyl sulfonium hexafluoroantimonate
Sinocure® 1206 Photoinitiator APi-1206

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