What is Pultrusion?
Pultrusion is a continuous low pressured molding process using fiber reinforcements and thermosetting resins matrices. The fiberglass reinforcements are drawn through resin baths or injected with resin in which all fibers are thoroughly impregnated with the liquid resin system. The wet-out fiber is formed to the desired geometric shape and pulled into a heated steel die. Once inside the die, the resin cure is initiated by controlling it at precise elevated temperatures. The composite laminate solidifies in the exact cavity shape of the die, as it is continuously “pulled” by the Pultrusion machine, thus getting the name – Pultrusion.
Can any shape be Pultruded?
Virtually any constant cross section can be pultruded dependent upon wall thicknesses and complexity of the cross section of the profile.
What are the most typical resins used in the Pultrusion process?
The most commonly utilized resins are standard thermosetting resins such as polyesters, vinyl, esters, epoxies, phenolics and urethanes. However, thermoplastic resins can also be used.
What are the most typical reinforcements used in the Pultrusion process?
Typical reinforcements used are fiberglass roving, continuous strand mat, and woven and stitched fabrics. Other reinforcing materials such as carbon and aramid fibers, which are more costly, can be utilized during the Pultrusion process to increase the modulus/stiffness of the composite member.
Do Pultruded parts need to be painted?
For most applications, internal coloration, surfacing veils and various UV stabilized additives eliminate the need for secondary painting applications. However, to improve the weathering properties or the appearances of a Pultruded profile during outdoor exposure, coatings are highly recommended. Most commonly used coatings are Acrylics and Urethanes.