Dynamic Shear Modulus Degradation Limits in High Speed Recyclable UV Resin Formulations
Dynamic shear degradation limits UV resin velocity at 280 m/min to prevent oligomer scission, balancing resin costs against full EPR fee savings.
Recyclable Overprint Varnish
Protective Coating
Transparent layers applied over printed matter that facilitate the separation of the film from the substrate during fiber recovery meet specific circularity criteria. A recyclable overprint varnish avoids the use of permanent crosslinking agents that would trap paper fibers in a plastic matrix. These coatings are designed to either dissolve in the pulper or break into discrete, non-tacky particles that are easily removed by standard screening equipment.
Compatibility with existing waste streams ensures that the treated board can be returned to the mill.
Repulping Efficiency
Dissolution or detachment of the layer depends on the chemistry of the binder system used in the formulation. While traditional coatings might create stickies that clog paper machines, a recyclable overprint varnish uses alkali-soluble resins or specific dispersion technologies to maintain process cleanliness. Testing protocols for these varnishes measure the percentage of fiber yield and the cleanliness of the resulting hand sheet.
Surface Function
Demand for scuff resistance and gloss remains high even when the material must be easily removable. The formulation of a recyclable overprint varnish balances the need for durability during shipping with the requirement for rapid breakdown in the recycling plant. Slip properties are adjusted to ensure the finished boxes stack safely without sliding.
Providing this protection without compromising the end-of-life value of the package is the primary goal of this chemistry.