RTM / Vacuum Infusion UPR (Low Viscosity)

CAS 26455-61-8In StockSample available

Key Features

  • Ultra-low viscosity (100-250 mPa·s) for complete preform penetration
  • Extended pot life (40-90 min) for large mold infusion
  • Isophthalic base for superior water resistance
  • Low void content (<1%) in vacuum-infused laminates
  • Sharp gel transition for clean mold release

RTM/Vacuum Infusion UPR is a low-viscosity, extended pot-life unsaturated polyester resin specifically engineered for closed-mold resin transfer molding (RTM) and vacuum-assisted resin infusion (VARI) processes. The resin's low viscosity of 100-250 mPa·s at 25°C enables rapid, complete fiber bundle penetration through multi-layer glass fiber preforms without dry patches.

The formulation provides extended gel time (40-90 minutes at 20°C with standard MEKP/cobalt systems) to ensure complete mold fill before gelation begins. Once gel is reached, sharp exotherm promotes complete through-cure. The resin is specifically designed for isophthalic acid base for improved water resistance and HDT versus orthophthalic grades.

Cured infused laminates at 50-55% glass volume fraction exhibit flexural strength of 250-350 MPa, tensile modulus of 18-22 GPa, and interlaminar shear strength of 25-35 MPa. The low void content achievable by vacuum infusion (<1%) gives superior mechanical consistency compared to hand lay-up. Suitable for wind turbine nacelle covers, automotive structural panels, marine hulls, and large industrial FRP components.

Specifications

ParameterValue
Acid BaseIsophthalic
AppearanceClear to pale yellow liquid
Density (25°C)1.12-1.14 g/cm³
Viscosity (25°C)100-250 mPa·s
Gel Time (20°C, 1.5% MEKP)40-90 min
Void Content (vacuum infused)<1%
Flexural Strength (50% Vf, cured)250-350 MPa

Applications

Vacuum infusion of large wind turbine nacelle coversRTM automotive structural panelsMarine hull closed-mold infusionLarge industrial FRP vessel infusionAerospace secondary structural infusion parts

FAQ

Maintain 95-98 kPa vacuum (near full vacuum, <0.05 bar absolute) throughout the infusion process. Higher vacuum improves resin flow, compaction, and reduces void content. Monitor for resin leaks at vacuum bag seals throughout infusion — any vacuum drop above 2 kPa/min indicates a leak that must be fixed before proceeding. After infusion is complete, maintain vacuum until the resin has fully gelled.

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