Roots of the name “Triplex” date back to World War I when war industry needed glass characteristic of more strength properties and safer for the people round about even in case of crashing. One British company engaged in production of glass provided a very interesting and still useful solution for safe and strong glazing. This company, which is now well known under the name of “Pilkington”, has invented a three-layer glass consisting of two external glass sheets with a plastic PVB film between them.
Such composition of glass, when two external glasses and a plastic film between them are used, provides glass with unique qualities. First of all glass becomes very strong and can withstand greater loads in all directions comparing with usual glass. Another important quality of such glass is that if a glass is damaged minimally, usually only the layer on that side of glass where the mechanical contact is encountered cracks, this means that under certain circumstances glass specialists could repair such glass in such a manner that no signs of the previous crack would be seen. Another important property included in international requirements for car windscreen performance is that in case of severe damage when even both glass layers are fragmented, the glass still remains at the glazing place and a minimum amount of fragments is overspread.
“Triplex” glass is manufactured in a manner similar to parts from carbon fibre. Both glass layers and elastic PVB film between them are glued (heated up) in a high temperature environment under vacuum in a special furnace called autoclave. Only at high temperature and vacuum gluing of glasses and a PVB film into a solid “Triplex” glass is successful so that no air bags would form between the layers and the glass would be characteristic of ideal optical properties.
We should also mention the fact that thinner glass sheets may be used in case of application of the above mentioned manufacture process comparing to the usual windscreen manufacture method. The windscreen should be made thick enough to obtain the same strength characteristics and this would impede the possibility to produce optically ideal car windscreens.
