interlayer material is not available to laminators. It is a
registered General Electric product used only by General Electric
for the lamination of their polycarbonate glazing laminates.
a) PVB Interlayer Material. Polyvinyl butyral is used
universally by the glazing industry for laminating glass products
together. PVB is the most cost-effective interlayer material
There are basically three grades available:
architectural, aircraft, and automotive. Architectural grade
and aircraft grade PVB are the most predominate grades of PVB
material for security glazing. Architectural grade PVB is the
most widely used. Aircraft grade PVB is approximately twice as
stiff as the architectural grade and is about four times as
Environmental durability of polyvinyl butyral is a
known and proven quantity. Long-term use in automobile and
aerospace windows indicates that few, if any, problems of
environmental degradation will be encountered.
b) Urethane. Polyether urethane interlayer material can
be used to laminate glass or polycarbonate materials.
Urethane material has better viscoelastic behavior at
low temperatures than PVB material. This behavior is beneficial
in applications involving high speed ballistic impacts at low
Currently, there are only two interlayer materials
which are compatible with polycarbonate for use in the lamination
These materials are urethane and Copal. Polyether
urethane is the only type of interlayer material which is
commercially available to laminators for the lamination of
Fragment Retention Film. The polyester film used in
commercial products is commonly referred to as fragment retention
film, safety film, security film, protective film, or shatter
resistant film. Fragment retention film is a system combining a
strong pressure sensitive adhesive with a tough polyester layer.
This film applies directly to the glass surface of a window pane.
It is beneficial for retrofitting existing windows although it is
also installed on new windows with the same benefits. Fragment
retention film behaves similarly to relatively thin laminated and
polycarbonate glazing in terms of fragmentation. It is available
in common thicknesses of 2, 4, 7, and 10 mils (0.05, 0.10, 0.17,
and 0.25 mm).