Designed to address photoinitiators shortage in UV-curable printing inks and varnishes
Decreasing the quantity of photoinitiators in a formulation is always a challenge. Sartomer's amine-modified oligomers allow the formulator to maintain good reactivity, even in systems with a low amount of photoinitiators, in both UV and LED curing.
Photoinitiators reduction influence
Amine-modified oligomers improve reactivity by reducing oxygen inhibition and easing photoinitiator activation. CN2565, LM7202 and PRO21398 exhibit the highest reactivity with a lower impact when decreasing photoinitiator levels.
For each formulations with an amine-modified oligomer and reduced photoinitiators quantity, UV dose has been measured and normalized against the corresponding standard composition, with both standard UV fusion and LED lamps.
Curing system optimization
Optimum cure performance is achieved through a combination of Sartomer's amine-modified oligomers, especially CN2565 and LM7202, and highly functional oligomers, enabling higher reactivity at low photoinitiator ratios.
* Photoinitiators by Lambson
Curing conditions :
- UV Heraeus lamp, 120 W/cm²
- LED Phoseon lamp, 395nm, 12 W/cm²
Reactivity assessed by dry rub resistance on 12 μm thick films
PI = Photinitiator UA = Urethane Acrylate
For each optimized composition with an amine-modified oligomer, reduced photoinitiators quantity and higher functional oligomer acrylate, UV dose has been measured and normalized against the corresponding standard composition, with both standard UV fusion and LED lamps.
The reactivity of the optimized composition - with less photoinitiators - is increased, noticeably in LED curing, as the required UV dose to obtain a cured film is reduced compared to the standard composition.
Urethane acrylate-based oligomer exhibiting superior mechanical properties with low shrinkage and good hardness/flexibility balance properties while ensuring very good reactivity.
Low-viscosity polyester acrylate-based oligomer combining good flexibility and enhanced adhesion properties, especially on plastic substrates. Ideally suited for use in flexo inks or inkjet as NVC replacement.
High-functionality polyester acrylate-based oligomer with balanced physical properties and superior pigment wetting, especially in flexo inks.