Resin Transfer Molding (RTM) UPR
Key Features
- Low viscosity at injection temperature for complete preform fill
- Controlled gel time window for large complex molds
- Sharp cure for fast demold and high productivity
- Closed-mold process — near-zero styrene emissions
- Compatible with glass, carbon, and hybrid fiber preforms
Resin Transfer Molding (RTM) UPR is a low-viscosity, well-characterized isophthalic unsaturated polyester resin engineered specifically for injection into closed RTM tooling at 2-10 bar injection pressures. The resin provides a predictable gel time window (20-40 minutes) after catalysis to allow complete mold fill before gelation, followed by a sharp exotherm for fast demold.
With a viscosity of 150-300 mPa·s at 25°C and 100-200 mPa·s at 40°C (heated tool), the resin flows readily through complex fiber preforms with minimal dry-spot risk. The isophthalic base provides better water resistance and higher HDT than orthophthalic grades, important for transportation and outdoor structural parts produced by RTM.
RTM-specific characteristics include low volatile emission during injection (closed mold) and compatibility with external release agent systems for tool release. Cured laminates at 45-55% fiber volume achieve flexural strength 200-280 MPa and ILSS (interlaminar shear strength) 25-35 MPa. The resin is compatible with glass, carbon, and hybrid preforms sized for polyester-compatible chemistries.
Specifications
| Parameter | Value |
|---|---|
| Appearance | Clear to pale yellow liquid |
| ILSS (50% Vf) | 25-35 MPa |
| Viscosity (25°C) | 150-300 mPa·s |
| Viscosity (40°C) | 100-200 mPa·s |
| Injection Pressure Range | 2-10 bar |
| Flexural Strength (50% Vf) | 200-280 MPa |
| Gel Time (25°C, 1.5% MEKP) | 20-40 min |
Applications
FAQ
Gel time is controlled through: (1) MEKP concentration (primary control): 0.5-2.0% at 25°C. (2) Cobalt octoate level (secondary control): 0.1-0.5%. (3) Mold temperature (tertiary): heated molds at 40-60°C significantly accelerate gel and cure. For production consistency, use a metering pump for MEKP injection and verify gel times daily using a small bench test at production temperature.
Direct Contact
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