Photoinitiator TPO-L

Photoinitiator TPO-L is an efficient liquid free radical photoinitiator with an absorption range of 270-370 nanometers and an absorption peak at 366 nanometers. When used in combination with photoinitiator 1173 and photoinitiator 184, it enhances the surface curing efficiency. It is suitable for screen printing inks, flexographic inks, solder mask inks, and photo resistants, especially for white and colored systems containing titanium dioxide and pigments.

Photoinitiator TPO-L is a high-efficiency liquid phosphine oxide photoinitiator designed for modern UV and LED curing systems. Compared with traditional solid photoinitiators, TPO-L offers low viscosity, easy handling, and superior compatibility with a wide range of oligomers and monomers.

It is widely used in UV coatings, printing inks, adhesives, electronics coatings, and 3D printing resins, especially where low yellowing and deep curing are critical.

Key Advantages of TPO-L Photoinitiator

• Liquid form – no pre-dissolution required
• Excellent absorption in 350–420 nm (ideal for LED curing)
• Low yellowing – suitable for clear and white systems
• Deep curing performance for thick films
• Low odor and improved formulation flexibility
• Better migration resistance vs traditional Type I initiators

Applications:

• UV LED Coatings: wood coatings, plastic coatings, clear varnishes
• Printing Inks: offset, flexo, screen inks, food packaging inks
• Adhesives: optical adhesives, electronic encapsulation
• 3D Printing: high-resolution photopolymer resins
• Electronics: conformal coatings and protective layers

Recommended Dosage

Typical dosage: 1% – 5% depending on formulation requirements and photoinitiator system.

Why Choose Liquid TPO-L Instead of TPO?

Unlike solid TPO photoinitiator, TPO-L eliminates dissolution issues and ensures faster formulation processing. Its liquid nature allows direct incorporation into formulations, improving production efficiency and consistency.

UV Absorption & Curing Mechanism

TPO-L is a Type I photoinitiator that undergoes α-cleavage upon UV exposure, generating free radicals that rapidly initiate polymerization. Its absorption spectrum matches modern UV LED sources (365–405 nm), making it ideal for energy-efficient curing systems.

Technical Specifications

• CAS No.:84434-11-7
• Chemical Name:2,4, 6-trimethylbenzoylphenylphosphonate ethyl ester
• Molecular Formula:C18H21O3P
• Molecular Weight: 316.3
• Other Name:Omnirad TPO-L
• Appearance: Pale yellow liquid

Package: 

25KG cartons

Storage and Transportation:

• Keep container tightly closed and dry and storage in cool place.
• Attention should be paid to avoiding light during production, manufacturing, storage and transportation.