Three breakout sessions showcase latest technologies being offered in the energy curing field.
One of the highlights of RadTech’s conferences are the sessions on new technologies. At RadTech 2022, there were three sessions dedicated to Next Level Formulations, with applications ranging from food packaging, wood coatings, automotive coatings and more.
Next Level Formulations I
Bruce Fillipo of Ashland led off the Next Level Formulations I session with “Monomer Impact on Optical Fiber Coatings,” a look at how polyfunctionals could impact optical fibers.
“We could get a synergistic monofunctional monomer’s properties with polyfunctionals – viscosity suppression and improved solubility,” Filippo noted. “Improved formulation homogeneity facilitates homogeneous crosslinking of polyacrylates.
“Vinyl pyrrolidone measured the best overall properties imparted to a primary optical fiber formulation, including excellent viscosity suppression, superior elongation and tensile strength, and greater than or equal cure rate vs. other evaluated monofunctional acrylates,” added Fillipo. “The properties targeted in optical fiber coatings are similar to other UV curable applications such as inks and specialty coatings.”
Marcus Hutchins of Allnex followed with “Achieving Ultra-Low Gloss Coatings Through Oligomer Design and Technology.” Hutchins discussed pathways to 100% UV coatings with matting agents, for example for wood.
“Options for further gloss reduction include resins with lower functionality and developing matting agents,” Hutchins added. “Lowering the gloss can lead to marring marks. You can create a wrinkle effect through excimer curing. Equipment set-up is key to ensuring a smooth surface without defects.
“Low matte finishes and high-performance coatings are becoming a reality,” Hutchins added. “UV curable materials can effectively matte through molecule design and technology, reducing the amount of matting agents needed and improving burnishing and stain resistance.”
Richard Plenderleith of Sartomer then talked about “Strategies Toward Reduced Migration Potential in Graphic Arts.” Plenderleith pointed out that about 70% of packaging is for food packaging.
Plenderleith added that standard UV inks are not suitable for direct food packaging, while low migration UV inks are required for indirect food packaging.
“Selection of optimized raw materials is key to minimize migration risks,” said Plenderleith. “Issues can occur from roll contamination during printing, UV lamps not curing throughout, or set-off migration upon storage. UV systems are part of food packaging industry growth as it is a solvent-free technology.”
Plenderleith pointed out that food packaging requirements are becoming more stringent.
“We do see a strong movement to UV LED, and development of efficient solutions fulfilling LED curing requirements is key,” he added. “Improving reactivity while reducing migration and hazards requires us to work on both photointiators and acrylates.”
Camila Baroni of IGM Resins closed Next Level Formulations I with “The Synergistic Effect of Combining Aminofunctional Materials with Type I Photoinitiators.”
“From the data shown so far, it looks like some of the acrylated amines are good oxygen inhibitors and have a potential as synergists in the presence of type 1 photoinitiators,” Baroni said. “The most reactive amines led to unwanted yellowing effect of the cured film. We have supposed that the yellowing can be reduced by fine-tuning of acrylated amine content.”
Next Level Formulations II
Next Level Formulations II began with “Small Particle Sizes Pack a Punch: Additive Options to Improve Surface Performance of UV Coatings Utilizing Cross-Linkable, Nanoparticle Dispersions or Micronized Wax Options,” presented by Brent Laurenti of BYK USA. Laurenti discussed UV crosslinking additives, SiO2 nanomaterials, additives and PTFE-free wax technology.
“PTFE-free waxes are giving us better leveling performance in some applications, and they are 100% biodegradable,” Laurenti reported. “It can go into almost any coating formulation.”
Next up was Tony Wang of Allnex, who talked about “LED Boosters to Improve Surface Cure by LED for Litho or Flexo Applications.”
“Oxygen inhibition quenches or scavenges radical polymerization,” Wang noted. “It is more severe in thin or low viscosity coatings, such as packaging coatings and inks. This can create a tacky surface. Surface cure is more challenging for LED cure because of low intensity and lock of shorty wavelength.”
Evonik’s Kai Yang then discussed “Promoting Energy Curable Adhesion to Difficult Substrate – From an Additive Aspect.”
“PDMS (polydimethylsilozanes) are the simplest class of siloxanes, and provide very low surface tension and is very stable,” Yang observed. “It offers good gliding properties. We improved compatibility by organic modification, which controls its hydrophobicity and hydrophilicity. Desired properties can be tailored by structural variation. We found that higher polarity improves solubility in UV matrix. TEGO Glide helps control the properties of organomodified siloxanes, while Tego RAD improves slip and release.”
Jason Ghaderi of IGM Resins closed Next Level Formulations II with his talk on “Urethane Acrylate Oligomers: Sensitivity of Cured Films to UV Light and Moisture with and without UV Absorbers.”
“All formulas based on UA oligomers showed no yellowing to the naked eye and virtually no yellowing nor discoloration as measured by the spectrophotometer,” Ghaderi said. “Soft urethane acrylate oligomers showed low tensile strength and modulus while exhibiting in high elongation. Semi-hard oligomers performance was in the middle, whereas hard oligomers resulted in high tensile strength and modulus with low elongation. It is observed that UV absorbers and HALS interfere with the cure, and as a result, crosslinking of cured film is lower than that of the system that lacks these two.”
Next Level Formulations III
Next Level Formulations III featured Joe Lichtenhan of Hybrid Plastics Inc., who covered “POSS Additives for Dispersion and Viscosity Control,” a look as POSS additives, and how they can be considered smart hybrid additives for coatings systems.
Lichtenhan was followed by Evonik’s Yang, whose second presentation was “The Use of Silica Additives in UV Printing Inks.”
“In UV/EB curing formulations, the surface treated silica is the preferred product since outstanding stability could be easier to achieve while maintaining a good viscosity for printing applications,” Yang noted.
“UV Curable Coating Options for Interior Automotive Applications,” by Kristy Wagner, Red Spot Paint, was next.
“UV curable clear and pigmented coatings have shown that they not only meet but exceed current OEM’s stringent specifications for interior automotive applications,” Wagner observed.
Mike Idacavage, Radical Curing LLC, closed with “Low Viscosity Urethane Oligomers that Function as Reactive Diluents,” which he noted could be used in inkjet, spray coating and 3D printing applications.
Post time: Feb-02-2023
