UV, UV LED and EB curing technology basics

Move to the HSE friendly and cost efficient UV, UV LED and EB curing technologies

UV curing process

UV LED EB curing technology principle

Know more about our cationic curing technology which uses UV light, and discover our UviCure epoxy/oxetane resins and SpeedCure photoinitators.

EB curing process

Specificities and advantages of EB curing

Definition:

EB : electron beam ➞ accelerated e-

 

Benefits:

 

  • No photoinitiators required ➞ minimized migration and low migration
  • High degree of conversion
  • Very high speed achievable allowing deep penetration for thick coatings
  • N2 atmosphere needed to avoid O2 inhibition
  • High energy radiation
  • Improved dot gain control
  • No heat for sensitive substrates
  • Highest performances : gloss, scuff and abrasion resistance
  • Suitable for highly pigmented formulations

 

Recommended applications:

 

Deep dive into EB curing technology

Principle of technology

 

Inside an ultra high vacuum chamber,an incandescent filament generates electrons. Then, the electrons are accelerated by a strong electrical field and exit the chamber through a thin titanium window.

 

 

Two variables matter particularly, the intensity (number of electrons generated per second) applied to the filament and the tension applied to accelerate these electrons.

 

The key parameters

 

With the EB curing technology, there are two key parameters that you can tune separately and independently from each other :

  • The dose (kGv) influences the flow of electrons: raising it is equivalent to increasing the  the number of electron hitting a certain surface area
  • The energy (kV) influences the penetration depth: increasing the energy is equivalent to amplifying the power of electrons that penetrate into the surface

  

 

Interaction with matter

 Let us imagine an electron penetrating an acrylate monomer/oligomer formulation to approach the interaction with matter.

An electron comes from the top, some collisions occur while penetrating the substrate. That the results of energy generation, the electron loses his energy along the trajectory and this energy is deposited in the matter.

 

Two scenarios:

  • The energy is high (or the coating is thin), the electron goes all the way through the substrate
  • The energy is low (or the coating is thick), the electron is absorbed by the matter

 

When the energy is deposited (red crosses), secondary slower electrons (blue circles) may be generated; they are slower than primary electrons.

 

 

Initiation mecanism

 

The low speed secondary electrons produced are solvated by the acrylate and allows the formation of a  radical anion. Then, the protonation (coming from impurities or traces of water) of this radical anion generates a free radical species. A free-radical initiated specie is produced and allow the polymerization start.

 

 

Thus, a primary electron generates many free radicals that will initate the polymerization reaction. The higher the primary electron energy is, the more free radicals are generated.  

 

 

Benefits of UV and EB curing technologies

  • Green technology
  • No solvent waste
  • Low hazard

 

 

 

  • Process efficiency and flexibility
  • Room temperature curing
  • Low heat generation
  • Simply adaptable to existing lines
  • Ease of cleaning

 

  • High productivity and cost savings
  • Reduced cycle time
  • Increased throughput
  • Instant on/off
  • Low energy consumption
  • No recycling of solvent wastes
  • Minor maintenance cost

 

The right curing materials for the best performance

Sartomer is a market-leading manufacturer of specialty acrylate resins designed for advanced UV, UV LED and EB curable systems:

Acrylate and methacrylate chemistry for UV LED EB curing technologies
Chemical performances for UV LED EB curing technologies

Towards UV LED curing

We believe UV-LED technology to be the future of UV curing, for it is a lower energy-consuming option than traditional Hg-doped lamps. It is also the technology of choice to coat or print on to heat sensitive substrates.

 

Benefits:

  • Very long lifetime and consistent energy output
  • No infra-red emission ➞ no heat generated
  • No warm-up time required
  • Compact and flexible lamp design
  • No generation of O3
  • Mercury-free system

 

 

Recommended applications:

  • Industrial coatings
  • Graphic arts
  • Food packaging
  • Electronics
  • Adhesives

 

Discover our recommendations to improve the performance of your UV-LED curing acrylate systems.

At Sartomer we have a strong technical expertise to support your development, please contact us to discuss the best solution for your formulation.

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