Adri van der Waals – COVESTRO
As demand for safer food packaging rises, ink and overprint varnish (OPV) formulators are turning to advanced UV-curable resins with lower migration. NeoRad™ S-8100 is a low-viscosity self-initiating resin, with reduced migration potential, making it particularly suitable for food packaging applications and enabling more cost-efficient packaging solutions.
Self-initiating resins are still growing in demand, and formulators want to move away from chemistries that merely reduce migration risk toward those with low to zero migration. That’s the customer need that the product is built to fulfil.
Adri van der Waals, Global Head UV Resins, Covestro, explains the main features fo the NeoRad™ S-8100 resin for the flexible packaging industry.
What challenges are faced by modern food packaging ink formulators?
Amid tightening sustainability targets and regulations, UV-curable resins are an increasingly attractive food packaging solution, as their fast, energy-efficient curing cuts VOC emissions and cost compared with thermal-cure alternatives.
However, fast UV curing requires the addition of a photoinitiator: a highly reactive molecule that carries the risk of migration into food. Conventional formulations default to polymeric photoinitiators (PPIs), which reduce that risk but don’t fully eliminate it, or to high-SML (specific migration limit) photoinitiators, which come with higher packaging formulation costs.
How does NeoRad™ S-8100 reduce the risk of migration?
NeoRad™ S-8100 addresses this trade-off, as it is a selfinitiating resin (SIR). SIRs build the photo initiating moieties directly into the resin acrylate backbone, so there’s minimal to near zero (<10ppb) possibility for migration to food.
This is not only an advantage over traditional UVcured resins, but also sets the product apart from other conventional SIRs on the market, which are typically based on benzophenone chemistry and require an additional amine synergist. This resin isn’t based on benzophenone and needs no additional amine. This means one less formulation variable to test, and less of the yellowing that amineboosted systems typically bring.
How does the resin support cost-effective, high-performance food-contact materials?
As a low-viscosity acrylate, NeoRad™ S-8100 is miscible and easily compatible with other acrylates across flexo, OPV, and offset printing alike. This also means formulators don’t need to add extra lowmolecular-weight monomers to adjust viscosity. These monomers are a common source of migratable residuals in radiation-curable systems.
Fast curing and low yellowing, and not needing additional amines are significant benefits of NeoRad™ S-8100 over the conventional SIR and PPI’s in reducing formulaton complexity in flexo inks and OPV’s. Low toxicity combined with versatile use in variety of sensitive applications makes this resin a cost-effective path to achieving safer food-contact materials without compromising on performance.
How does NeoRad™ S-8100 comply with current and upcoming food-packaging regulations?
NeoRad™ S-8100 is a REACH- polymer, and its raw materials meet the food safety criteria set out in the Swiss Ordinance and the German Ink Ordinance. EuPIA guided possible worst case migration calculations and extraction analysis supports suitability for indirect food contact packaging applications.
Because the chemistry itself is safe by design, rather than assessed on a formulation-by-formulation basis, customers can simplify the testing process for formulation adjustments.
How does support from Covestro hel p enable compliant UV-cured food packaging materials?
Guideline formulations from Covestro provide starting points for flexo, OPV, and offset applications, already balanced for target viscosity. This allows formulators to experience how the product behaves in combination with other formulation components. Samples are also available through a Covestro representative for testing in-process.
NeoRad™ S-8100 is optimized for UV light curing today, but for formulators tracking the industry’s shift toward LED light curing, Covestro can also share more about our ongoing development work in this area.
Key benefits
– Low-to near zero (<10ppb) migration: photoinitiating chemistry is built into the acrylate backbone.
– Low viscosity: enables compatibility with other acrylates across flexo and offset printing, as well as OPVs.
– Fewer additives: no additional amine synergists required, reducing yellowing.
– Regulation compliant: meets Swiss Ordinance and German Ink Ordinance food-contact requirements.
– Cost-effective: versatility across flexo and offset applications, ease of miscibility and no need for additional synergists enable low total cost of ownership.
