Glass fibre

The standard general purpose grade of glass fibre, originally developed for electrical insulation applications, hence the E designation. It accounts for the great majority of glass reinforcement used in composites and its composition is defined in standards such as ASTM D578.

A composite of glass fibre reinforcement in a polymer matrix, most commonly polyester or vinyl ester resin. GRP is widely specified for boat hulls, tanks, enclosures, cladding and cold-applied flat roofing thanks to its corrosion resistance, mouldability and moderate cost.

A non woven glass reinforcement made from chopped strands distributed randomly and held with a powder or emulsion binder that dissolves in styrene based resins. It gives roughly equal in plane properties in all directions, wets out readily by hand lay up and is the standard reinforcement in GRP flat roofing laminates. It is specified by areal weight.

A bundle of parallel, untwisted glass fibre strands wound onto a cylindrical package. Direct rovings feed processes such as filament winding, pultrusion and weaving, while assembled (multi end) rovings are designed for chopping in spray up; rovings are specified by tex and by sizing type.

A thin surface treatment applied to fibres during manufacture, typically containing film formers, coupling agents such as silanes, and processing aids. It protects the filaments during handling and, critically, controls adhesion and compatibility between the fibre and the matrix resin, so it must be matched to the resin system in use.