Spray-Up Grade UPR
Key Features
- Low viscosity for clean spray-up gun atomization
- Wax-based styrene suppressant for non-tacky surface cure
- Good balance of pot life and cure speed
- Compatible with standard chopped strand spray-up guns
- Pre-accelerated cobalt variants available
Spray-Up Grade UPR is an orthophthalic unsaturated polyester resin optimized for pneumatic spray-up equipment, where resin and chopped glass fibers are simultaneously deposited onto a mold surface. The resin is formulated with low viscosity (250-450 mPa·s) for clean atomization through spray-up gun tips (typically 1.5-2.5 mm orifice), and incorporates wax-based styrene suppressant for surface cure on open-mold laminates.
The wax additive (typically a dissolved paraffin wax at 0.1-0.3%) migrates to the laminate surface during cure and forms a thin protective film that suppresses styrene evaporation and ensures a non-tacky, tack-free surface finish. This is critical in open-mold spray-up where large surface areas are exposed.
Gel time at 25°C with 1.5% MEKP is 12-20 minutes, providing adequate working time between passes. The resin delivers flexural strength of 110-125 MPa at 25-30% glass content. Pre-accelerated variants with factory cobalt are available. Suitable for boat hulls, bathtubs, agricultural tanks, containers, and any open-mold spray-up FRP application requiring consistent quality at production throughput.
Specifications
| Parameter | Value |
|---|---|
| Appearance | Clear to pale yellow liquid |
| Density (25°C) | 1.12-1.14 g/cm³ |
| Styrene Content | 35-40% |
| Viscosity (25°C) | 250-450 mPa·s |
| Gel Time (25°C, 1.5% MEKP) | 12-20 min |
| Wax Content (styrene suppressant) | 0.1-0.3% paraffin |
| Flexural Strength (cured, 25% glass) | 110-125 MPa |
Applications
FAQ
Spray-up laminates typically contain 20-30% glass by weight, compared to 40-60% in hand lay-up with woven fabrics or 55-70% in filament winding. The lower glass content results in lower mechanical properties but faster deposition rates. The chopped roving length is typically 25-50 mm, set by the gun's cutter. Longer fibers (50 mm) provide higher mechanical properties at the cost of reduced conformability.
Direct Contact
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