Pure UV curing, the starting point for dual-curing UV resins, has long been a mainstream process in the fields of coatings, inks, and adhesives, owing to its advantages of “seconds-to-cure, solvent-free operation, and low energy consumption.” However, it suffers from a critical limitation: “it cannot cure beyond the reach of light.”
When dealing with scenarios such as 3D irregular parts, deep grooves and narrow slots, solid-color thick coatings, and shadowed areas of electronic components, pure UV curing often proves ineffective, leading to incomplete curing, poor adhesion, and inadequate weather resistance.
The advent of dual-cure UV resin was specifically designed to overcome this technical bottleneck. By leveraging a dual curing mechanism—UV photopolymerization combined with dark curing (via heat, moisture, or anaerobic conditions)—this resin enables the formation of an interpenetrating polymer network (IPN), achieving rapid surface curing in illuminated areas coupled with deep curing in dark regions. This approach balances processing efficiency with superior performance, establishing it as a key strategic direction for high-end UV materials.
I. What is dual-curing UV resin?
The dual-curing UV resin incorporates both photoinitiating groups (e.g., acrylate double bonds, epoxy groups) and dark-curing groups (e.g., hydroxyl groups, NCO groups, siloxane groups, anionic groups) within a single formulation. Through two independently controllable curing pathways, it achieves complete cross-linking of the coating or adhesive layer.
Core Logic:
❶ First stage (UV curing): seconds to surface dryness, rapid positioning, and formation of initial strength;
❷ Second Stage (Infrared Curing): Penetrating into shaded areas, thick layers, and dead zones to achieve complete cross-linking and enhance overall performance.
The resulting interpenetrating polymer network (IPN) structure can effectively relieve internal stress, significantly enhancing adhesion, temperature resistance, chemical resistance, and flexibility.
II. Four Mainstream Dual-Curing Systems: Principles, Key Features, and Selection Criteria
1⃣ UV + thermal dual-curing (most mainstream and widely used)
chemical principle
The resin contains acrylate double bonds (UV radical polymerization) and hydroxyl/epoxy groups (thermal crosslinking); after rapid surface drying under UV irradiation, heating (60–120 °C) completes deep curing, resulting in the formation of a dense IPN network.
Typical System
❶Hydroxyl acrylate + isocyanate (PU dual-curing)
❷Epoxy acrylate + amine/anhydride (dual-epoxy curing)
core advantage
✅ The shaded area has completely solidified
✅ Suitable for thick coatings (>100 μm) and solid-color/colored paint systems
✅ Exceptional adhesion (PC/ABS/Metal/Glass)
✅ Excellent temperature resistance, resistance to boiling water, and chemical resistance
applicable scene
Automotive interior coatings, 3C housing clear varnishes, PCB solder mask inks, coil coatings, and wood finishing varnishes.
2⃣ Dual-curing with UV and moisture (single-component, no heating required)
chemical principle
The resin contains acrylic ester double bonds and isocyanate (NCO)/siloxane groups; after UV surface curing, it undergoes slow crosslinking via reaction with moisture in the air, requiring no additional heating equipment.
core advantage
✅ Single-component, stable during storage (when sealed)
✅ Simple manufacturing process, ideal for complex structural components
✅ Low coefficient of contraction, high insulation properties, and resistance to thermal shock
applicable scene
Electrical hermetic coating, chip underfill, camera module bonding, and precision component packaging.
UV + Anaerobic Dual-Curing (Specialized for Metal Bonding)
chemical principle
The UV curing agent achieves rapid surface drying; upon isolation from oxygen (e.g., in metal gaps or slits), the anoxic functional groups undergo self-polymerization and curing, thereby delivering high-tensile strength bonding.
core advantage
✅ Fast positioning, no adhesive leakage
✅ The metal exhibits high bonding strength and excellent vibration resistance.
✅ Suitable for thread fastening and structural bonding
applicable scene
Metal threaded fasteners, bearing fasteners, and hardware structural adhesives.
UV + Cationic dual-curing (low shrinkage, optical grade)
chemical principle
UV light initiates cationic polymerization of epoxies/vinyl ethers; the reaction continues in the dark zone without the need for heating, resulting in low shrinkage and low stress.
core advantage
✅ Extremely low shrinkage rate (<1.5%)
✅ High light transmittance, low yellowing
✅ Excellent adhesion to glass and ceramic surfaces
applicable scene
Optical lens bonding, glass cover plate lamination, and light guide plate encapsulation
III. Dual-Curing vs. Pure UV: Key Advantage Comparison
IV. Comprehensive Analysis of Key Industry Applications
✅ Electronics and Electrical Appliances (largest application market)
❶PCB circuit boards: solder mask ink and conformal coating to ensure proper curing of component shadows, thereby enhancing salt spray anddamp heat resistance;
❷ Consumer Electronics: UV + hot-clear lacquer coating for mobile phone/tablet casings; scratch-resistant, alcohol-resistant, and fingerprint-resistant;
❸ Chip packaging: underfill resin application, camera module bonding, featuring low coefficient of thermal expansion, high dielectric strength, and deep curing.
✅ Automotive Industry (High-Growth Sector)
❶ Interior trim coating: dashboard and door panels feature UV + PU dual-curing technology, offering weather resistance, chemical resistance, and high gloss finish;
❷ Headlight/Glass bonding: UV + cationic system, featuring high light transmittance, superior bonding strength, and low yellowing;
❸ Power batteries: structural adhesives and sealants; offer temperature resistance, vibration resistance, and reliable insulation performance.
✅ Adhesives and Inks
❶ Structural adhesive: for metal/plastic structural bonding; features UV curing with thermal curing, offering high strength and impact resistance;
❷ Premium inks: suitable for glass and ceramic printing; offer strong adhesion, scratch resistance, and defect-free thick-film performance;
❸ Labels/Tapes: UV + moisture-resistant system, suitable for bonding labels on curved surfaces and irregularly shaped substrates.
✅ Industrial Coatings
❶ Woodware/Furniture: UV + thermal varnishing; delivers high saturation, resistance to yellowing, and a threefold increase in efficiency;
❷ Coils/Metals: anti-corrosion coating—weather-resistant, salt-spray resistant, and crack-resistant under thick coating conditions;
❸ Leather/TPU: Flexible coating, offering high flexibility, excellent fold resistance, and crack resistance.
V. Key Considerations for Equipment Selection: Four Steps to Precisely Align with Your Requirements
Select type based on process
① Single-component, no heating required → UV + humidity
② High strength, temperature resistance → UV + heat
③ Metal bonding → UV + anaerobic
④ Optical, low shrinkage → UV + Cationic
Select the appropriate system based on the substrate
❶PC/ABS/Plastic → PU Acrylate
❷ Glass/Optics → Epoxy Cationic
❸ Metal/Ceramic → Epoxy/PU dual-curing
❹ Flexible substrate (TPU/leather) → low functionality, high flexibility system
3⃣ Adjust the formulation based on performance
① High hardness → Increased functional groups
② High flexibility → Reduce crosslinking density
③ Low yellowing → Aliphatic PU/epoxy system
④ Chemical resistance → High crosslinking density, epoxy modification
4⃣ Cost balancing
❶ Premium application scenarios (electronics/automotive) → Imported / high-end domestic products (Storm, Zhanxin, leading domestic brands)
❷ Mid-range application scenarios (coatings/inks) → Cost-effective domestic systems
VI. Market Trends and Future Outlook
❶ Rapid growth in market size: the share of the dual-curing system is projected to rise from 15% in 2022 to 28% in 2025, with a compound annual growth rate exceeding 15%;
❷ Accelerated domestication: the domestication rate of high-end dual-cured resins is advancing from 31% to 60%, with industrial clusters emerging in Kunshan, Suzhou, and the Pearl River Delta region;
❸ Technological Iteration: Low energy consumption, low yellowing, ultra-fast curing, and bio-based raw materials have become key research and development focuses;
❹ Application Expansion: New energy, semiconductors, healthcare, and flexible electronics will emerge as new growth drivers.
epilogue
Dual-curing UV resin represents not only an advancement in UV technology, but also an inevitable choice for industrial manufacturing to evolve toward higher efficiency, precision, and reliability. By leveraging the synergistic power of “light + dark,” it breaks through the limits of curing processes and empowers high-end manufacturing.
The UV curing adhesive range named above is one part of the JOME production line. For the earlier discussion of Hidden Materials in the Photovoltaic Industry UV, follow the link, or browse the the full JOME bonding solutions line; specifications and samples go through the send drawings to the JOME team.