company news about How can UV curing technology bridge the gap between "low VOC" and "low odor"?

Against the backdrop of increasingly stringent environmental regulations, UV (ultraviolet) curing technology, with its inherent advantage of "near-zero VOC emissions," was once considered a "top student" in the coatings and inks industry. However, as consumers' demands for product experience continue to rise, a new challenge is becoming increasingly acute: "low VOC (volatile organic compounds)" does not equal "low odor." Whether it's skin-friendly phone coatings, safe food packaging, or everyday home decoration materials, a pungent odor has become an unacceptable defect. Therefore, "low odor" is rapidly evolving from a quality-enhancing "bonus" to a crucial "entry barrier" in market competition. This market-driven formula upgrade focuses primarily on the upstream—raw material selection.

• Unreacted residual monomers: This is the primary contributor to odor.
• Photoinitiator (PI) itself and its degradation byproducts: This is the "hidden culprit" in the formulation.
• Some low molecular weight resins (oligomers): Although not the main cause, they can affect the overall tone of the system.

• Environmental Regulations Driven: VOCs are the main pollutants in the production and use of coatings and inks. Environmental regulations in the EU and China are becoming increasingly stringent. For example, the "Emission Standard for Air Pollutants from Printing Industry" (DB 31/872) explicitly requires that the organic solvent content of radiation-cured inks be extremely low, with almost no VOC emissions.
• Explosive Market Growth: The Chinese low-VOC curing agent market is projected to exceed US$10 billion by 2025, maintaining a high compound annual growth rate, primarily driven by the green transformation of downstream industries. The global UV curing system market is expected to double to US$15.28 billion by 2030, with a compound annual growth rate of 17.9%.
• User Experience Needs: "Low odor" is key to user experience. Pungent odors not only affect the health of workers in production environments such as furniture factories but are also a major cause of consumer complaints. Low-odor systems can directly enhance product competitiveness.

Achieving low odor is a complex "systems engineering" project, requiring formulation engineers to find a delicate balance between odor, cost, curing efficiency, and physical properties. This raw material upgrade battle focuses on three core components.

1. Monomers – Say Goodbye to the "Low Price, Low Viscosity" Cult
   Monomers (reactive diluents) are the largest contributor to odor in UV formulations and are also the most easily misunderstood element. Traditionally, engineers tend to use monomers with low viscosity and high dilution capacity, such as IBOA and TPGDA. However, low viscosity often comes with low molecular weight and high volatility, which is the "original sin" of odor.
   Selection Strategy Analysis:
   • First Principles: Shift to "High Molecular Weight, Low Vapor Pressure". Prioritize monomers with higher molecular weight and more stable structures (e.g., higher alcohols or PO-based modifications). Vapor pressure is significantly reduced, minimizing volatility at the source.
   • Reassess "Functionality": Using multifunctional monomers (such as trifunctional and tetrafunctional monomers) can reduce the total amount of monomers used, thereby indirectly reducing odor. However, this needs to be balanced with the crosslinking density and flexibility of the system.
   • Recognize the reality: The "low-odor monomers" in the industry are not "zero-odor" but "low-volatility," which are usually accompanied by lower reactivity. This requires synergistic upgrades to initiators.

Achieving low odor is a complex undertaking, not simply a matter of replacing a single raw material.

• The decisive factor is the process: Raw materials determine the "theoretical minimum" odor, while the curing process determines the "actual residual value." Insufficient UV energy or severe oxygen inhibition can lead to excessively high monomer residues, making the odor even stronger.
• The double-edged sword of LEDs: While LED cold light sources reduce the volatilization of monomers due to heat, they also "lock in" the range of PI (polyimide) choices, requiring reliance on long-wavelength PIs (such as TPO and 819). The byproducts of these PIs are precisely the main source of odor. This necessitates that LED formulations rely more heavily on macromolecular or polymeric PIs.

Therefore, in the leap from "low VOC" to "low odor" in UV curing technology, formulation engineers need a holistic perspective, balancing the activity, cost, and volatility of raw materials, and optimizing the process to ultimately meet the higher demands of the market and environmental regulations for product experience.