Structural Composite Technologies

The Pultrusion Process

Reinforcement 1

Reinforcement 2

Resin Tank

Preformer

Haul Off Device

Heated Die

Finished Sections

Cut Off Saw

Resin Tank

Pultrusion is a continuous process of pulling resins and reinforcing materials through a heated die, forming profiles of uniform cross section in a continuous length.

Pultrusion gets its name from the method by which the profiles are made. Raw materials are pulled by "the puller" which is located just before the final cut-off saw. The "puller" is made up of pulling pads that grip the product and drive the process.

The pultrusion process involves:

• Reinforcement 1 - Unidirectional roving, the reinforcing fibre that runs along the length of the profile.
• Reinforcement 2 - The fibre mat is added in which is a multi-directional reinforcement.
• The resin, typically vinyl ester for increased durability and strength.
• The fibre is fully wetted with the liquid resin and pulled into a preformer for aligning the reinforcements.
• Then into the heated die where curing takes place.
• Once  the material enters the die, a surface veil may be added which enhances the final product's surface appearance.
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All the resins used in the pultrusion process have a catalyst or hardener added when the resin is mixed which is activated at about 93°C. Consequently, as the wet reinforcement passes through the heated die, the product changes from liquid to a solid profile with all the reinforcement laminated within.

The product is the pulled through the die by "the puller ". The final product is then cut to the desired length.

Multi-directional

fibre reinforcement

Continuous aligned fibre reinforcement

Surface veil