Abstract
This study explores the synthesis and application of SINOMER UVP4606, a low-viscosity, halogen-free, and high-hardness hexafunctional polyester acrylate designed to replace SINOMER DPHA (Dipentaerythritol Hexaacrylate) in industrial coatings. The resin demonstrates comparable performance to DPHA while offering cost advantages and improved processability. Applications include plastic matte roller coatings, plastic spray coatings, and PCB inks.
1. Introduction
DPHA, a dipentaerythritol hexaacrylate, is widely used in coatings for plastics, floor tiles, roller coatings, wood finishes, and PCB inks due to its high crosslinking density, rapid curing speed, and excellent hardness. However, its high cost and production inefficiencies limit its broader adoption. This paper introduces SINOMER UVP4606, a polyester acrylate that matches DPHA’s performance while reducing costs and enhancing formulation flexibility.
2. Experimental Section
2.1 Reagents and Equipment
- Resins: Epoxy-based compounds and acrylic acid intermediates
- Monomers: SINOMER TMPTA, TPGDA, HDDA.
- Photoinitiator: 2-Hydroxy-2-methyl-1-phenyl-1-propanone (Sinocure 1173).
- Equipment: UV lamp scratch tester (Biuged 520/2), 60° gloss meter.
2.2 Synthesis of SINOMER UVP4606,
A four-neck glass reactor was charged with epoxy-based compounds and acrylic acid intermediates (molar ratio 1.05:1). Catalysts (3000 ppm) and inhibitors (800 ppm) were added. The mixture was heated to 75°C, then gradually raised to 100°C over 2.5 hours, held at 100±1°C for 1.5 hours, and further heated to 115°C over 1.5 hours (total reaction time: 7.5 hours). The product was cooled when the acid value reached 1.0–2.0 mgKOH/g.
2.3 Performance Comparison:SINOMER UVP4606 vs. DPHA
| Property | SINOMER UVP4606 | SINOMER DPHA |
|---|---|---|
| Color (Fe-Co) | ≤1 | ≤1 |
| Viscosity (cPs, 25°C) | 2800–3200 | 5500–8000 |
| Acid Value (mgKOH/g) | 0.5–1.0 | 0.5–1.5 |
| Appearance | Clear, colorless | Clear, colorless |
| Yellowing Resistance (ΔB) | 5.08 | 8.24 |
| Scratch Resistance (1 kg) | >1000 cycles | >1000 cycles |
| Hardness (Pencil) | 2H | 2H |
| Curing Speed (mJ/cm²) | 50 | 40 |
| Halogen Content | None | None |
| Cracking Resistance (300 mJ) | No cracking | Cracking |
| Water Resistance (24 h) | No blistering | Blistering |
| Adhesion | Grade 0 | Grade 0 |
3. Applications
3.1 Matte Roller Coatings for Plastics
| Component | Ratio (%) | Coating Properties | Process Parameters | Film Performance |
|---|---|---|---|---|
| SINOMER UVP4606 | 9 | Viscosity: 1000 cPs/25°C | Coated on PVC (25 μm), cured at 200 mJ/cm² | Adhesion: Grade 1 (cross-cut test); scratch resistance: 150g/150mm (no marks); gloss: 1.0 (black), 3.3 (white). |
| Other components* | 91 | Flowability: Excellent | ||
| Conclusion: SINOMER UVP4606 enhances wear resistance in plastic roller coatings. |
3.2 Spray Coatings for Plastics
| Component | Ratio (%) | Coating Properties | Process Parameters | Film Performance |
|---|---|---|---|---|
| SINOMER UVP4606 | 27 | Viscosity: 9 s (Ford Cup #4) | Sprayed on PC, cured at 600 mJ/cm² | Adhesion: 5B; water resistance (80°C/30 min): Passed; scratch resistance: >500 cycles (steel wool), >1000 cycles (A4 paper). |
| Conclusion: Ideal for high-durability plastic spray coatings. |
3.3 PCB Inks
| Component | Ratio (%) | Coating Properties | Process Parameters | Film Performance |
|---|---|---|---|---|
| SINOMER UVP4606 | 15 | Viscosity: 16,000 cPs/25°C | Coated on copper substrates (10 μm), cured at 300 mJ/cm² | Insulation: >10¹² Ω; adhesion: Grade 0; hardness: 2H; alkali resistance (1.5% NaOH, 30 s): Passed; thermal cycling (-20°C to 125°C): No cracking. |
| Conclusion: Suitable for high-performance PCB inks requiring thermal and chemical stability. |
4. Cost Analysis
Advantages: Lower cost, reduced viscosity for easier formulation adjustments.
5. Conclusion
SINOMER UVP4606 , a halogen-free hexafunctional polyester acrylate, exhibits performance parity with DPHA in hardness, curing speed, and durability while offering cost savings and process advantages. Successful applications include plastic coatings, spray coatings, and PCB inks, demonstrating its versatility as a DPHA alternative.
Keywords: Low-viscosity polyester acrylate, SINOMER UVP4606, DPHA replacement, UV-curable coatings, halogen-free resins.