CEILING PANEL AND METHOD OF MANUFACTURE

Abstract: A ceiling panel (5) capable of bending into the shape of an arc, for forming a curved ceiling (10), and a method of manufacturing the ceiling panel. The ceiling panel comprises a mineral wool layer (2') with fibers bonded together, the direction of the fibers being mainly perpendicular to the underlayer fabric (3) which is made from glasswool and attached to one side of the fiber layer, onto the surface of which underlayer fabric a coating fabric (6) made from glasswool is laminated. The panel is manufactured from a mineral wool mat (1) which is coated on both sides thereof and in which, when the panel is viewed in a horizontal position, the fibers of which have been caused to rise from the normal, horizontal position to a vertical position in the manufacturing stage of the mat.

Description: Ceiling panel and method of manufacture The present invention relates to a ceiling panel capable of bending into the shape of a curve and a method of manufacturing such. For purposes of noise damping and interior features, glasswool panels installed with the help of support moulding are generally used in ceilings. A flat ceiling is not difficult to make, but construction of a curved ceiling is complicated. Until now, curved ceilings have been made of pressed-to-shape pieces, the manufacture of which calls for expensive moulds and the transport of which is difficult. Furthermore, fitting the pieces together in the assembly stage sets great demands on the dimensional accuracy of the pieces. An object of the invention is to provide a panel capable of bending into the shape of a curve, by means of which panel the drawbacks described above can be avoided. Another object is to provide a method of manufacturing such panel. The ceiling panel according to the invention is mainly characterized in that it comprises a mineral wool layer containing fibers bonded together, the direction of extension of the fibers being mainly perpendicular to an underlayer/layer fabric attached to one side of the fiber layer. The method according to the invention for manufacturing ceiling panels is mainly characterized in that a mineral wool mat which is coated on both sides thereof with an underiayer fabric and the fibers of which mat have been caused to rise from a horizontal position to a mainly vertical position at the manfufacturing stage of the mat, is cut along its centerline into two layers and that the layers cut apart from each other are cut into panels of a suitable size. In the mineral wool panels produced by conventional manufacturing processes, the fiber structure is, for technical reasons, primarily parallel to the surface of the panel, which is why the compression strength of the panel is low in the direction perpendicular to the plane of the panel. Many methods are known in which a mineral wool mat is divided into lamellas, which are turned 90° and re-combined with each other in order to achieve a vertical fiber structure i.e. perpendicular to the plane of the panel, and consequently, a higher compression strength. The panel according to the invention is manufactured from a mineral wool sheet, the main portions of the fibers of which axe, in the ■ mani'fcic-turing stage -with *the panel regarded lying in a horizontal position, forced to rise fxom the hitherto normal, horizontal disposition to a substantially vertical disposition in such a manner that the fibers proceed steeply wavelike in the base sheet when viewing the profile of the base sheet. This is brought about by decreasing the speed of the mineral wool mat between the top and the bottom wires used in the manufacturing prior to conveying the mat into the heat treatment oven for hardening of the bonding agents. This "shrink" panel is already coated on both sides thereof in the processing stage with an underiayer fabric (25 - 50 g/m 2 glass tissue) which provides an even base for final coating of the panel. The underiayer fabric is attached to the base sheet by means of the resin contained in the base sheet. The base sheet is made twice as thick as that required for the final product plus working allowance. This base sheet which is coated on both sides thereof with an underiayer fabric and which naturally is stiff in this stage, is sawn along its centerline into two layers. In that way, one surface of both layers is coated with an underiayer fabric, which provides an even base for the final coating. In the middle of the base sheet, the fibers are mainly in the vertical position. After sawing, the final product has, due to the presence of vertical fibers, sufficient compression strength and solidity so that the panel can be installed to rest freely on mouldings. On the other hand, since the sawing of the base sheet in two is effected mainly perpendicularly to the fibers, the tensile and compression forces are not subjected to the fibers in the direction of the fibers when the sheet is being bent, but perpendicularly to the fibers. Thus, the sheet bends well because of lack of horizontal bonds in the back thereof. The base sheet layers sawn apart are laminated with a final coating fabric on that side -which is coated with an underiayer fabric. The invention is further described in more detail below, by way of example, with reference to the accompanying drawings, in which Fig. 1 is a cross-sectional illustration of a stage of manufacture of a ceiling panel in accordance with the method of the invention, Fig. 2 is a cross section of a panel according to the invention, and Fig. 3 is a schematic, fragmentary perspective illustration of a ceiling structure assembled from ceiling panels according to the invention. A glasswool mat 2 illustrated in Fig. 1 is manufactured by a method known per se from fibers and bonding agents suspended in a gas flow by collecting the fibers onto a conveying belt, below which a suction box is disposed. By decreasing the speed of the glasswool mat formed thereby between the upper and the lower conveyors in two stages, the main length of the fibers are forced to rise from their normal, horizontal position to a vertical position so that the fibers will mainly extend in the vertical position in the middle of the mat. Thereafter, the fiber mat is coated on both sides thereof with an underiayer fabric 3, which is attached to the mat by means of the resin contained in the mat. After the heat treatment, the coated mat 1 is sawn or otherwise separated along its centerline 4 into two layers 2' and the sides of the layers sawn apart from each other which are coated with the underiayer fabric 3 are laminated with a coating fabric 6, whereafter they will be cut into ceiling panels 5 (Fig. 2) of a suitable size. The underiayer fabric 3 is preferably formed of nonwoven fabric made from glasswool, the basis weight of such fabric beiϊg 25-50 g/m 2 . The coating fabric 6 is preferably formed of nonwoven fabric made from glasswool, the basis weight of such fabric being 50-200 g/m 2 . The thickness of the mineral wool layer is preferably 30- 70 mm and the density 30-40 kg/m 3 . Fig. 3 illustrates a ceiling assembly 10 including ceiling panels 5 according to the invention, in which ceiling the panels 5 are bent to form curves to match the curved support moulding 11 and fixed to it, the ceiling itself is suspended by a method known per se with suspension threads 12 extending from the frame construction of the building and the coating fabric 6 forms a smooth suspended ceiling surface which is easy to maintain clean. Example A mineral wool mat, the density of which was about 30 kg/m 3 and thickness 65 mm and which was on both sides thereof coated with glass fabric of 25 g/m 2 , was sawn into two 30 mm thick layers. The surfaces coated with glass fabric of the layers sawn apart from each other were then laminated with another glass fabric, the basis weight of which was 60 g/m 2 . Thereafter, the layers were cut into ceiling panels of 600 mm x 1200 mm. The end product was a flexible panel, the stiffness of which was adequate for installing the panel to rest at its edges on T-moulding. Besides freedom of design the ceiling panel of the invention provides ceilings which are easy to install. Transport of the panels causes no problems because the panels are flat and not bent intc the shape Of an axe or curve until the installation stage. The invention is not limited to the embodiment described above, but it can be modified within the scope defined in the accompanying claims. Thus, plastic laminates can be used as the coating fabric of the panel. It will be understood that the panel can be used to other purposes as well.

Claims: AMENDED CLAIMS [received by the International Bureau on 7 September 1990 (07.09.90); original claims 1-4 cancelled; claim 5 amended and renumbered as claim 1; claims 6 and 7 unchanged but renumbered as claims 2 and 3 (1 page)] 1. A method of manufacturing a ceiling or other panel, characterized in that a mineral wool mat coated on both sides thereof with an underiayer fabric, the fibers of which mineral wool mat have been caused to rise in the manufacturing stage between top and bottom wires from a horizontal position extending generally in the plane of the panel mainly to a perpendicular position, is cut along its centerline into two layers and that the layers cut apart from each other are cut into panels of a suitable size. 2. The method as claimed in claim 1, characterized in that the underiayer fabrics are attached to the mineral wool mat by means of its own bonding agent in the manufacturing process of the mineral wool mat. 3. The method oa claimed in claim 2, characterized in that the sides coated with an underiayer fabric of the layers cut apart from each other are laminated with a coating abric.

Inventors: HYNNINEN KARI, JALONEN ANTTI, LAAKSO SIMO, SALO MATTI, HYNNINEN, KARI, JALONEN, ANTTI, LAAKSO, SIMO, SALO, MATTI
Applicants: AHLSTROEM ERISTEET OY
Application year: 1990
Main classification: E04B9
IPC codes: E04B9