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SIMPREX® H325 is an advanced vinyl ester prepreg designed to provide good fire retardance properties (V-1 flammability rating). It is ideal for manufacturing sandwich structures, providing good adhesion to core materials such as Nomex® honeycomb, balsa and foams. SIMPREX® H325 is a great choice for many applications in the range of low to medium service temperature, where a high degree of fire retardance is required.

Polymer Name: Vinyl Ester Resin

Functions: Prepreg

Reinforcement Material: Glass Fibers

Processing Methods: Compression Molding, Prepreg Processing, Vacuum Bagging

End Uses: Aerospace Applications, FRP Boats, Motorsport

Technical Data Sheet
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Identification & Functionality

Polymer Name
Reinforcement Material
Composite Materials Functions

Features & Benefits

Features
  • Prepreg
    • Fast curing cycle: 15-20 min @ 250°F.
    • Tack time of pieces kept with release film: 3 - 5 hours @ 68°F (Tack can be reactivated with a hair drier during lamination).
    • Roll tack time out of the bag (with the shrink-film): more than 24 hours @ 68°F.
    • Suitable for low pressure: 1-3 bar.
    • Excellent flexibility and handling.
    • Controlled flow for ease processing (autoclave, press-mold & vacuum bagging).
  • Laminate
    • High degree of resistance to mechanical and chemical damage.
    • High degree of fire retardance (UL-94, V-1 flammability rating).

Applications & Uses

Typical Applications

FRP parts for chemical resistance purpose.

  • FRP parts requiring fire retardance.
  • Secondary aircraft structures.
  • Racing vehicles.
  • Marine.
Curing Conditions

In press-mold, laminates should be cured for 15-20 min @ 250°F (121°C) / 1-3 bar. Pressure should increase gradually to reach its maximum within 60-90 sec. In some applications, a post-cure @ 266°F (130°C) is recommended for optimum performance.  

  • Laminates up to 1/8” (3 mm) thick can be cured without dwell time. A dwell time should be considered according to thickness and heat-up rate, which depends on the mass, type of tool and molding process (vacuum and autoclave).
  • If a prepreg sheet is maintained long time out of the bag before lamination, and lost its tack, heat it with a hair dryer to reactivate the tackiness.

Properties

Flame Rating
Physical Properties
ValueUnitsTest Method / Conditions
Standard Weight (Without Release Film)0.089lb./sq. ft.
Standard Resin Content36.0%
Standard TackGood Tack on Both Sides
Cured Ply Thickness0.254mm
Laminate Properties

3 mm thick, cured @ 250ºF (121ºC), for 15 min. & Post-cured @ 266ºF (130ºC)

  73°F 165°F
Flexural Strength, MPa (ASTM D790) 550-570 450-470
Flexural Modulus, GPa (ASTM D790) 26-30 24-26
Interlaminar Shear Strength, MPa (ASTM D-2344) 44-46 31-33

Glass Transition Temperature (DSC): 130-135ºC 

Regulatory & Compliance

Certifications & Compliance

Safety & Health

Handling and Safety Precautions

Usual precautions should be observed. The prepreg contains mainly uncured synthetic resins. The operator has to use appropriate mask - respirator and work in a clean, dry (R.H. = 50% or less) and ventilated area. The use of clean disposable inert gloves provides protection for the operator and avoids contamination of material and components.

Storage & Handling

Shelf Life
1 Year
Storage

SIMPREX® H325 prepreg should be stored in its original packaging film (humidity and airproof), or an equivalent barrier film, at 68°F (20°C).