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What is a photoinitiator

What is a photoinitiator

Photoinitiators, also known as photosensitizers or curing agents, are a type of compound that can absorb energy at a certain wavelength in the ultraviolet (250-420nm) or visible (400-800nm) region, produce free radicals, cations, etc., and thus initiate monomer polymerization, crosslinking, and curing. Today we will talk about the photoinitiator 819 product.

Photoinitiator 819 is an efficient photoinitiator suitable for initiating radiation polymerization reactions of unsaturated resins under ultraviolet light irradiation, especially suitable for white formulations and glass fiber reinforced polyester/styrene systems, as well as for outdoor varnish systems in combination with light stabilizers.

Basic information of photoinitiator 819 chemicals:

Product Name Photoinitiator 819
Other Name Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; UV 819; IRGACURE 819; Uv Photoinitiator 819
CAS 162881-26-7
Molecular formula C26H27O3P
Molecular weight 418.46
Density  1.19 g/cm3
Melting point  127 ~ 131.5℃
Boiling point  ≥168℃
Appearance yellow powder
Content ≥ 98% (liquid chromatography)
Vapour pressure 5 × 10-10 kPa (25 ℃)
UV absorption peak 295, 370nm

IRG 819

Composite application of photoinitiator 819

IRG 819 can be used in conjunction with other photoinitiators, such as IRG 184 or IRG 651

The combination of IRG 819 and IRG 651 is particularly suitable for curing polyester/styrene resin systems, such as in fiberglass reinforcement materials.

Due to its absorption in the long wavelength range, IRG 819 can be used in combination with UV absorbers such as TINUVIN 400, making it suitable for UV cured coatings that require weather resistance.

Recommended dosage:

Transparent acrylic and unsaturated polyester/styrene coatings 0.1-0.2% IRG 819+1-2%

IRG 184

White acrylic and unsaturated polyester/styrene coatings 0.5-1% IRG 819+1-2%

IRG 184

Colored acrylic formula 0.5-1% IRG 819+1-2% IRG 184

White screen printing ink 0.5-1.5% IRG 819+1-2% IRG 184

Fiberglass reinforced unsaturated polyester/styrene prepreg 0.1-0.2% IRG 819

What are the applications of photoinitiator 819?

Photoinitiator 819 is a commonly used chemical substance commonly used in the field of photocuring. Photopolymerization is a technique that uses ultraviolet or visible light to initiate chemical reactions. Photoinitiator 819 is commonly used as an initiator in photocurable materials to initiate UV polymerization reactions in unsaturated prepolymer systems. Mainly applied in the following fields:

Ink printing: In UV ink, photoinitiator 819 can help ink solidify quickly, improve printing speed and production efficiency.

Coatings: Used in UV coating systems, it can achieve rapid curing and hardening of coatings, improving their wear resistance and weather resistance.


Adhesive: In UV or LED light cured adhesives, photoinitiator 819 can promote the curing reaction of the adhesive, improve bonding strength and durability.

UV cured resin: can be used to prepare UV cured resins, such as UV cured coatings, UV cured adhesives, UV cured adhesives, etc.

Overall, photoinitiator 819 plays an important role in promoting curing reactions in the field of photopolymerization, and can be used in various coatings, inks, adhesives, and resin systems that require rapid curing and hardening.

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