GENERAL INFORMATON
	ADVANTAGES OF PULTRUDED COMPOSITES

GENERAL INFORMATION

The pultrusion process
The pultrusion process, very similar to extrusion, is the only continuous process for the production of composite profiles. In pultrusion, reinforcing materials (glass, Kevlar or carbon fibres) in the form of continuous rovings, mats and other types of fabrics, are pulled through a resin matrix bath or other impregnation device, then carefully guided through a pre-shaping station followed by a heated, high precision, die in which the resin matrix sets at high temperature to form the final product. Finally, the hardened profile is continuously pulled past a saw, activated to cut it into pre-determined lengths.

Pultruded composites
A pultruded composite is generally made up of reinforcing materials (glass, Kevlar, carbon fibres) held together by a rigid resin matrix (polyester, vinylester, epoxy thermosetting resin). Often, surface veils are incorporated to improve weathering and corrosion resistance.
 
The sketch below shows a typical section of a pultruded profile for general use.

For special applications, the reinforcement can be of different types and nature (fabrics, woven rovings; carbon or aramid). Although most profiles utilise a thermosetting polyester resin matrix for specific applications, other types of resin may be used, such as acrylics, vinylester or epoxy.
It is not possible to indicate physical or mechanical data applicable to all pultruded profiles because the characteristics may vary greatly due to several factors: 

• Type, quantity and orientation of the reinforcement; 
• Type of resin, nature and content of fillers; 
• Geometry of the section.

The table below shows average values for the main characteristics of profiles made with isophthalic polyester resin reinforced with glass fibres, for two types of reinforcement composition:

	Reinforcement made entirely of glass rovings in the profile axis direction
	Reinforcement arranged as shown in the sketch above

For comparison we also indicate values for steel and aluminium.

	GRP	GRP		Steel	Aluminium
Glass reinforcement content by weight (%)	75	65
Density (g/cm³)	2.0	1.8		7.8	2.7

Other typical properties

Note: For structural applications it is important to consult our technical department.