High-Reactivity UPR (Fast Cure)
Key Features
- Gel time 8-15 min for rapid production cycle
- Hard cure in 20-30 min at 25°C
- Effective cure at lower temperatures (>12°C)
- High peak exotherm aids through-cure in thin sections
- High maleate ratio for maximum cross-link density
High-Reactivity UPR is an orthophthalic unsaturated polyester resin formulated with a high maleate/fumarate ratio in the polymer backbone and optimized styrene content to deliver the fastest possible cure response when activated with MEKP and cobalt accelerator systems. This resin is intended for production environments where cycle time is paramount and rapid mold turnover is required.
With 1.5% MEKP and 0.5% cobalt octoate at 25°C, gel time is 8-15 minutes and hard cure (Barcol 35+) is achieved in 20-30 minutes. Peak exotherm temperature is 180-220°C in bulk samples, requiring careful laminate thickness management (maximum 4-5 mm per layer) to avoid thermal degradation or microcracking.
The high exotherm also promotes rapid cure in cold workshop environments (>12°C) where standard grades may gel too slowly. Flexural strength is 115-130 MPa at 25-30% glass content, modulus 3.5-4.2 GPa. The resin is widely used in high-volume production of sanitary ware, small marine craft, and industrial components where 3-4 parts per hour cycle rates are needed.
Specifications
| Parameter | Value |
|---|---|
| Appearance | Clear to pale yellow liquid |
| Styrene Content | 38-42% |
| Viscosity (25°C) | 300-500 mPa·s |
| Peak Exotherm (bulk) | 180-220°C |
| Flexural Strength (cured) | 115-130 MPa |
| Time to Barcol 35 (25°C) | 20-30 min |
| Gel Time (25°C, 1.5% MEKP) | 8-15 min |
Applications
FAQ
Limit to 4-5 mm wet thickness per pass. The high exotherm (180-220°C peak) in thick sections can cause thermal stress cracking, surface blistering, and smoke generation in laminates over 6-8 mm applied at once. For thicker structures, apply in 3-4 mm layers and allow each layer to reach Barcol 25-30 before applying the next. Multiple thin passes produce better mechanical properties than single thick applications.
Direct Contact
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