company news about Breakthrough in 0.7 seconds! Water-based UV inks conquer the adhesion problem of coated paper

While traditional water-based UV inks offer the environmental advantage of low VOCs (volatile organic compounds), their adhesion to smooth coated paper surfaces is often insufficient, leading to print peeling and limiting their application in high-speed printing scenarios with high quality requirements.

This study, through customized synthesis of HEMA (hydroxyethyl methacrylate)-containing polyurethane and precise control of the reactive diluent ratio, summarizes a series of key technical indicators:

• Ultra-fast curing: Curing speed reduced to an astonishing 0.7 seconds, meeting the efficiency requirements of modern high-speed printing presses in China.
• Ultra-high adhesion: The final ink system achieved an adhesion test of 98%, with significantly enhanced abrasion resistance, solving the problem of easy damage to finished products during logistics and use.
• Precise formulation: Optimal performance relies on 3.1% Irgacure 907 photoinitiator, 7.5% WPU-g-HEMA resin, and a specific ratio of reactive diluent.
• Contact angle: 53° – exhibiting excellent wetting properties, contributing to ink leveling on smooth surfaces.

This breakthrough did not rely on a single raw material, but rather stemmed from systematic formulation optimization:

• Resin modification (WPU-g-HEMA): Instead of using general-purpose resins, researchers synthesized a polyurethane containing HEMA (hydroxyethyl methacrylate). Introducing HEMA groups not only provides double bonds to participate in the photocuring reaction, but its hydroxyl structure also increases hydrogen bonding with paper fibers, thus significantly improving adhesion.
• The golden ratio of reactive diluents: Research found that a 1:5 ratio of DETA (diethylenetriamine) to GMA (glycidyl methacrylate) yielded the best results. This combination reduced system viscosity without sacrificing crosslinking density.
• Initiator efficiency optimization: At a 3.1% Irgacure 907 photoinitiator concentration, the system achieved the optimal balance between photosensitivity and curing depth.

The value of this research lies not only in the laboratory data, but also in the two key signals it sends to the market:

1. First, it breaks the performance bias of "water-based UV": For a long time, downstream printing plants have been hesitant about water-based UV inks, primarily concerned that they are "usable but not durable." This research demonstrates that through molecular-level grafting modification, water-based systems can achieve or even surpass the physical properties (such as abrasion resistance and adhesion) of some solvent-based products. The 98% adhesion rate is an indicator that crosses the practical threshold.
2. "0.7 seconds" is the ticket to commercialization: For packaging and printing companies, time equals profit. Traditional water-based inks often require long thermal drying tunnels, resulting in high energy consumption and low efficiency. This technology compresses the UV curing time to 0.7 seconds, meaning that existing UV printing equipment only requires minor process adjustments (mainly pre-treatment dehydration) to directly apply this new ink, significantly reducing equipment modification costs for companies.
3. Second, it precisely targets niche markets: Coated paper is widely used in high-end food packaging, cosmetic outer boxes, and pharmaceutical labels. These fields have extremely high requirements for residual monomer migration (safety) and appearance gloss (aesthetics). The success of this technology means that the final piece of the puzzle for "solvent-free" packaging is being completed.

While traditional UV inks cure quickly, they still contain a certain amount of active monomers and are mostly solvent-based or high-viscosity formulations, making them unsuitable for all sensitive applications. Traditional water-based inks, although environmentally friendly, suffer from poor adhesion to high-gloss coated paper surfaces, limiting their application in high-quality printing. The newly synthesized water-based UV polyurethane ink combines the environmental friendliness (solvent-free) of water-based inks with the high efficiency (ultra-fast curing) of UV curing, while simultaneously solving the key obstacle of adhesion. This technological breakthrough will directly benefit fields with extremely high safety and print quality requirements, such as food packaging and high-end label printing, accelerating the transformation of these fields from traditional inks to more environmentally friendly green printing technologies.