industry applications

UV/LED Curing and Printing

Photopolymerization technology is composed by UV lamps, monomers and photoinitiators, either driven by free radical curing mechanism or cationic one. Over the last 30 years, we have seen photopolymerization developed into diversified industries and opened up new markets, from traditional overprint varnishes, wood coatings, to electronic usages such as solder masks, optical adhesives, or even nail gels or dental treatments. The disruptive innovation overwhelms some old fashioned processing by significantly reduced equipment space, fast curing as a finger flicks, and handheld devices made for easy handling…etc.


Photoinitiators are light-sensitive chemicals that undergo a chemical change, broken down into free radicals when they absorb radiant energy, such as ultraviolet light.

Based on the operating principles of photoinitiators, they can be simply categorized into "free radical photoinitiators" and "cationic photoinitiators," with "free radical photoinitiators" further divided into Norrish Type 1 and Norrish Type 2.

🔹 Free Radical Photoinitiators: Norrish Type 1 and Norrish Type 2 Photoinitiators

  • Norrish Type 1 Photoinitiators: Commonly known as photoinitiators, the molecules self-decompose into free radicals upon absorbing radiant energy.

  • Norrish Type 2 Photoinitiators: Commonly known as photosensitizers, they absorb UV energy and transfer it to photoinitiators. Typically, amine synergists are used in conjunction to achieve a co-initiation effect.

🔹Cationic Photoinitiators:

Unlike free photoinitiators, cationic photoinitiators release a photoacid during the photolysis process, and then induce the ring-opening polymerization of epoxy resin through the generated photoacid.

🔹Hybrid Systems:

  1. Combination of Acrylic and Epoxy Mechanisms: A hybrid system that undergoes curing through both acrylic and epoxy mechanisms simultaneously. This provides flexibility for the material in various applications.

  2. Synergistic Action: Utilizing two different photo-initiation mechanisms simultaneously to promote the polymerization process in a more comprehensive and efficient manner.

  3. Application Flexibility: Suitable for applications requiring different polymerization mechanisms, such as Stereolithography (SLA) or Digital Light Processing (DLP).

Through the use of a hybrid system with photoinitiators, a more flexible and efficient light-curing solution can be achieved.

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