Veterans in the UV curing industry all know that UV resin serves as the core backbone of any formulation system, directly dictating finished product performance, construction outcomes and service life. Many purchasers and formulators prioritize unit pricing above all else and blindly chase low-cost raw materials, only to encounter recurring defects including brittle coating films, poor adhesion, easy yellowing and incomplete curing. The expenses incurred from rework and customer complaints far outweigh any savings from cheaper pricing.
Price should only act as a reference when selecting UV resin; five core performance metrics determine a product’s true value. We break down each indicator below to help users source materials accurately and steer clear of common procurement pitfalls.
1.Functionality: Determines curing speed, hardness and shrinkage rate
Functionality refers to the quantity of active groups on resin molecules available for UV curing reactions and ranks as the primary reference for material selection; resins of varying functionality differ drastically in applicable scenarios.
- Low functionality (1~2 functional groups): Low reactivity and slow curing speed, yet outstanding molecular flexibility and low volumetric shrinkage. The cured film resists cracking under bending and stretching, widely applied to flexible films, soft adhesives, nail gels and leather coatings and other applications requiring deformability.
- Medium functionality (3 functional groups): Balanced overall performance with a favorable combination of curing rate, hardness and flexibility. It is the dominant option for coatings, general inks and conventional adhesives, compatible with most common working conditions.
- High functionality (4~6 or more functional groups): Extremely high reactivity enables rapid curing and yields hard, scratch-resistant and abrasion-proof films, accompanied by high shrinkage and brittleness. Ideal for high-hardness topcoats, rigid plastic coatings and heavy-duty abrasion-resistant inks, yet not recommended for flexible substrates.
Selection Tip: Avoid blindly opting for high-functionality resins. Substrate properties and target hardness of finished products are the core criteria to confirm required functionality.
2.Viscosity: Impacts Construction Performance & Formulation Blending
Viscosity of UV resin directly affects the leveling property, coating appearance and construction efficiency of the system, serving as a critical reference for formulation preparation.
High-viscosity resins feature high molecular weight and deliver superior adhesion and chemical resistance after film formation. However, poor leveling is prone to occur when used alone, triggering coating defects such as cratering, pinholes and orange peel, so reactive monomers are generally required for dilution. Low-viscosity resins boast favorable fluidity for easy application and require fewer additional monomers, cutting system odor and VOC content, yet some ultra-low-viscosity variants compromise coating mechanical strength.
Select resins matched to your production process: opt for proper viscosity grades for spray or curtain coating to prevent extra formulation costs from excessive post-dilution. Meanwhile, pay attention to viscosity stability; premium resins maintain slight viscosity fluctuation during storage without thickening or caking.
3.Flexibility and Adhesion: Core Guarantee for Matching Various Substrates
Even with perfect curing results, products will end up scrapped once peeling or cracking occurs, making these two indicators top concerns for end users downstream.
- Adhesion: Resins vary greatly in surface wetting capacity when applied to diverse substrates including plastics, metals, glass, wood and PET films. Some low-cost resins feature mismatched surface tension, leading to coating blistering and delamination in a short period. Pre-sample testing is mandatory for notoriously hard-to-bond substrates.
- Flexibility: Rigid and brittle coatings tend to crack easily under bending, stamping or alternating hot-cold conditions. Flexibility is a critical inspection item for soft plastics, films and decorative edge wrapping applications. For high-hardness requirements, coatings need to be rigid yet not brittle to strike a balance between hardness and toughness.
4.Weather Resistance and Anti-Yellowing Performance: Determine the Service Life of Finished Products
Yellowing and gloss loss are the most common after-sales defects of UV-cured products, with stringent requirements specified for outdoor goods, white/light-colored coatings and high-end decorative components.
Conventional aromatic UV resins come at lower cost, yet their molecular structures are vulnerable to UV radiation, high temperature and moisture, gradually turning yellow and dull after long-term service. In contrast, aliphatic and modified resins deliver outstanding anti-yellowing performance and superior weather resistance, suited for demanding applications including outdoor coating, pale-hued finishes and accessories adjacent to food-contact materials.
For end-consumer retail or outdoor-oriented products, anti-yellowing and anti-aging properties shall be prioritized. Differences remain invisible in the short run but become distinctly apparent after prolonged usage.
5.Odor and VOC Content: Dual Requirements for Regulatory Compliance & Production Environment
With increasingly stringent environmental regulations nowadays, low odor and low VOC have become mandatory industry benchmarks, which also bear directly on workshop working conditions and employees’ health.
For applications including daily chemicals, nail art products, food packaging and indoor coating, always select UV resins featuring low odor, low migration and full regulatory certification. Compliance effectively mitigates operational risks.
Summary
When purchasing UV resins, calculating the overall comprehensive cost matters far more than focusing solely on unit price. Low-cost raw materials seem cost-saving at first glance, yet subsequent losses from rework, customer complaints, environmental rectification and product scrapping usually end up being counterproductive.
Feel free to leave a message for consultation if you encounter challenges in formula tuning or resin selection, and let’s discuss technical issues regarding UV curing together!
Post time: Jun-05-2026
