All present license agreements and license productions are based on this generation.
A tubular coextruded film is "melt oriented" mainly in the longitudinal direction as it leaves the extruder. In a second step without any further stretching, the tube is helically cut to form biased orientation. In a third step two or more such films are laminated and biaxially stretched in low stretch ratios at relatively low temperatures, the transverse orientation being in several steps between intermeshing grooved rollers with a fine pitch.This grooved-rollers stretching does already produce bonding. Heat treatment at the end of the stretching line for stabilization and further bonding.
The polymer material for the main layer of coextrusion is a blend, either PP with a softer copolymer admixed, or a blend of HMWHDPE and LLDPE. On both sides of the main layer coextruded surface layers: "lamination layer" to establish the bonding within the laminate, and "heat seal layer" which becomes an external layers of the laminate.
Developments on laboratory and pilot scale were carried out in Denmark in 1970-77 by O-B R and his employed technicians.
The first two industrial plants were built in 1977. Developments in connection with "2nd generation XF" have continued after the first commercialization and resulted in inventions which are listed and briefly explained below. Most of these inventions are commercially utilized. Especially important have been 4 inventions in connection with grooved roller stretching, by which the production capacity has been substiantially increased, and several material characteristics improved.
License productions were started almost simultaneously in Norway by Graenges Essem Plast and in England by a subsidiary of Reed International. It has been a big pioneering task for both companies, technically as well as commercially, on the technical side mainly performed by Reeds two technical leaders, Mr. Peter Orlowski and Mr. Patrick Coffey. (Mr. Coffey is now O-B Rs consultant). (Unfortunately the English XF-production was stopped after about 20 years performance, mainly successful, since new owners wanted to concentrate their efforts on their core business, paper).
Later licensees, namely in Japan, Brazil, Switzerland, Spain, Columbia, India, Belgium and 2 in the USA have also performed remarkable effort, to convince their markets of the merits of an unknown type of product.