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.
Ester-Cleavable Acrylates
Reactive Monomer
Specialized chemical building blocks containing internal ester bonds allow for the controlled breakdown of crosslinked polymer networks. When formulated into coatings, ester-cleavable acrylates provide the mechanical strength and chemical resistance required during the life of a package. These substances participate in the same free radical polymerization as standard acrylates but include a specific chemical weakness in their spine.
This weakness remains stable under normal use conditions (such as room temperature and neutral humidity).
Degradation Trigger
Exposure to highly alkaline environments or specific enzymatic catalysts initiates the hydrolysis of the internal bonds. Once the ester-cleavable acrylates encounter a hot caustic wash, the polymer chains fragment into smaller, water-soluble components. The speed of the reaction is governed by the concentration of the wash solution and the temperature of the bath.
Recycling Utility
Efficiency in de-inking operations increases when the cured film can be reduced to microscopic particles that do not redeposit on the fibers. Because ester-cleavable acrylates facilitate the removal of uv-cured layers, they enable the recovery of higher quality secondary fibers. Standard uv inks often form a plastic skin that is difficult to screen out during pulping.
These degradable components ensure that the coating does not interfere with the brightness or strength of the recycled paper.