In the field of industrial coatings and electronic packaging, uniform curing and mechanical properties of thick coatings (>500μm) have always been technical difficulties. Traditional single curing modes (such as pure UV or pure thermal curing) are prone to uneven curing, shrinkage cracking and other problems due to insufficient light penetration depth or accumulated thermal stress. For this reason, dual curing systems (Dual Curing Systems) have become an ideal solution for efficient curing of thick coatings by combining cationic-free radical hybrid mechanisms with photothermal synergistic triggering technology. Shenzhen U-Sunny Technology (U-Sunny) provides high-performance dual curing technology support to the industry with its Uyracure series of initiators and hybrid resins.
1. Core technical advantages of dual-cure system
Synergistic improvement of deep curing and low shrinkage
The dual-cure system achieves rapid surface curing (drying within 30 seconds) under UV light through the complementary mechanism of cationic ring-opening polymerization and free radical chain growth reaction, and triggers deep crosslinking through thermal activation (80-120℃). Youyang U-9310 hybrid resin adopts a synergistic formula of sulfonium salt initiator (such as T-205) and acrylate monomer to reduce the volume shrinkage of thick coating to less than 2%, significantly reducing microcracks caused by internal stress.
Enhanced environmental adaptability
Combined with UVLED cold light source (no infrared radiation, surface temperature rise <5℃) and low-temperature thermal initiator, the system is suitable for heat-sensitive substrates (such as plastics, optical lenses) and can maintain stable curing efficiency in high humidity environments. For example, Youyang CTI-150 thermal initiator can still maintain an activity retention rate of more than 95% under 85% RH conditions.
Optimized process flexibility
Supports staged curing control:
First stage: 365nm UV light (500mJ/cm²) completes 80% surface cross-linking to prevent sagging;
Second stage: 80℃ heat curing for 30 minutes to achieve deep and complete polymerization.
This mode is compatible with continuous production lines and intermittent processes, and is suitable for a variety of application scenarios such as electronic packaging adhesives and automotive structural adhesives.
2. Typical application scenarios and formula design
High-precision electronic packaging materials
Recommended formula: U-Sunny U-9310 hybrid resin (60%) + CTI-150 thermal initiator (2.5%) + UM-440 low viscosity monomer (25%) + silica powder (12.5%)
Performance: Cured thickness up to 2mm, dielectric constant ≤2.9 (1MHz), glass transition temperature (Tg) 180°C, no delamination after 1000 times of -40°C↔125°C thermal cycle test.
Automotive structural adhesive and anti-corrosion coating
Technical highlights: With UVLED surface light source (9600mW/cm²), surface drying within 10 seconds, subsequent thermal curing at 80℃ for 1 hour, salt spray resistance test for more than 3000 hours, adhesion (cross-cut method) reaches level 0. Youyang UM-470 chemical-resistant monomer can further improve acid and alkali resistance (10% H₂SO₄ immersion for 30 days, ΔE<1.5).
Optical lens lamination bonding
Process advantages: UV pre-curing (3 seconds) is used to fix the lens position, and then deep cross-linking is completed by 120℃ gradient heating, light transmittance>92%, haze<0.3%, avoiding deformation problems caused by traditional thermal curing.
3. Four Values of Choosing U-Sunny Dual-Cure Solution
Technology Collaborative Innovation
U-Sunny's unique cation-free radical hybrid patent system breaks through the limitation of a single curing mechanism, and combines the synergistic effect of Uyracure initiator and UV resin to increase curing efficiency by 40%.
Balance between environmental protection and cost
The low VOC formula (<50g/L) complies with EU REACH regulations, and the amount of thermal initiator added is only 0.5-3%, and the overall cost is 25% lower than that of the traditional system.
Global certification support
The product has passed UL, ISO 10993 (biocompatibility) and RoHS certification, and is suitable for high compliance requirements in the automotive, medical and other fields..
Visit U-Sunny's official website to download the "Thick Coating Dual Curing Technology White Paper" or contact the technical team (+86-13686844208) to customize your exclusive solution!
