Three-layer laminated panel and method for production

DETAILED DESCRIPTION It has surprisingly been found that when using a mainly closed-cell structured polyurethane foam of a density of at least 40 kg/m.
sup.
3 and a polychloroprene rubber-based contact adhesive as the adhesive, three-layer laminated panels having facing sheets or layers of glass enamelled metal can be produced in a simple way.
These three-layer laminated panels are weatherproof and dimension stable, even when exposed to the weather for a long time.
Accordingly, the three-layer laminated panel of the invention is characterized by the polyurethane foam sheet having a density of at least 40 kg/m.
sup.
3, and by at least one of the facing sheets or layers being a metal sheet which is glass enamelled on both sides.
As mentioned above, either one of or both of the metal sheets may be glass enamelled.
It is preferred to use glass or porcelain enamelled steel plates.
When one of the metal sheets is not glass enamelled, it is e.
g.
made of galvanized steel, copper or aluminum.
In a preferred embodiment of the three-layer laminated panel of the invention the polyurethane foam has a density of 50-120 kg/m.
sup.
3.
When the three-layer laminated panel of the invention is used as e.
g.
facade cladding the polyurethane foam may contain fire retardants, if desired.
The method of the invention is characterized by applying a polychloroprene rubber-based contact adhesive to two opposite sides of a polyurethane foam sheet of a density of at least 40 kg/m.
sup.
3 and of mainly closed cell structure, drying the contact adhesive, if necessary, at a temperature above room temperature, placing the two metal sheets both being coated on one side with polychloroprene rubber-based contact adhesive and subsequently dried, if necessary at a temperature above room temperature, and at least one of said two metal sheets being glass enamelled on both sides, on each side of the polyurethane foam sheet coated with contact adhesive with the contact adhesive layers facing the contact adhesive layers of the polyurethane foam sheet to form a three-layer laminated panel, then placing said panel in a suitable press under a pressure of at least 5 kg/cm