METHOD FOR THE SEALING OF THE OPENINGS IN THE SURFACE OF FLAT, LAYERED SYNTHETIC MATERIAL AND FOIL FOR THIS PURPOSE

Abstract: Method for the sealing of the openings (7) in the end surfaces (6) of a sheet-shaped synthetic material consisting of two or more outer plates (2, 3) which are mainly flat and which are installed on part­ itions (4), which are placed on roughly even distance from one another and run along the total length of the material, more or less parallel, whereby over every opening (7) a dust-proof, water-vapour permeable and ventilating first foil (11) is put, and on top of that one or more strips of a second foil (8) are put, of which the edges (9) are beaten around the outer plates (2, 3), and which are fixed to these outer plates. This is done in such a way, that every opening (7) discharges, at least partially, under a part of the first foil (11) which is not covered by the second foil (8). The invention comprises the foil mater­ ial to be used, preferably consisting of two strips of foils, fixed against each other before it is put over the openings (7).

Description: The invention relates to a method for the sealing of the openings in the end surfaces of a flat construction consisting of two or more outer plates of synthetic material which are mainly flat and which run mainly parallel to each other and are connected to each other by means of spacer bars, which bars are placed roughly on even distance from one another and run along the total length of the construction. Such a construction of plates of synthetic material is used, for instance as a covering for street lights etc. The synthetic material which then is chosen is light-permeable, like for instance the polycarbonates known under the registered trade marks 'Lexan', 'Macrolon' and 'Perspex'. The covering then consists of one or more layers of adjoining, parallel channels with a roughly rectangular cross-section, situated between two outer plates. In order to prevent dampness, fungus etc. from penetrating into the channels, the end openings of the channels are sealed with a material that is dust-proof, water-vapour permeable and ventilating. Such materials are known. Certain so-called 'non-woven' synthetics meet these demands. Then, such a material in the form of a foil, is placed over the openings, so, that it is glued against the outer plates, on both sides of the openings. In practice, such a sealing does not suffice: the mechanical strength of the foil mentioned proves to be insufficient and it also proves to be impossible to glue the foil tight enough to the outer plates. The invention is based on the insight, that it is possible to make a sealing that combines the characteristics of a material like the nonwoven synthetic mentioned, to the favourable mechanical properties- the strength -, of foils of other materials like aluminum. The method for sealing the openings mentioned, according to the invention, is characterised in that a dust-proof, water-vapour permeable and ventilating first oil is placed over every opening, wholly or partly covering it, and that on top of that are placed one or more strips of a second foil, the edges of which are folded around the outer plates, and which are fixed to these outer plates. This is done so that every opening discharges, at least partially, under a part of the first foil which is not covered by the second foil. According to a preferential realisation of the method of this invention, on top of the first foil one strip of the second foil is applied, provided with holes, placed in such a way, that after its attachment every opening discharges under at least one hole, and that the back side of every hole is covered totally by the first foil. A relatively wide strip of the second foil is glued to the outer plates, for instance with an adhesive, put on the strip in advance. Of course, such an adhesive will be applied also where the second strip covers the ends of the spacer bars, and where it covers the first foil. The holes in the second foil are, for instance, slots that lie in a row, in the middle of the strip. A simplification of the method according to the invention is achieved according to another characteristic of it, by attaching the first foil, as a strip, over all openings. A way of applying the method according to the invention is that two strips of the second foil are applied on respectively upper and lower edge of the strip of the first foil, leaving uncovered a part along the middle of the first foil. A still further simplification, according to the invention, is achieved, when before the foils are applied, the first foil is already combined with the second foil and, according to this realisation of the method: is attached under the holes in the second foil to form a foil assembly, after which the assembly is placed over the openings. Attaching the two foils to each other is realised by glueing them together, seeing to it that when a second foil with holes is used, the holes need to be totally covered by the first foil. In order to be sure that in the sealed channels no fungus and algae can thrive, to the first foil of, for instance, non-woven synthetics, before it or the foil assembly is placed over the openings, respectively is attached to the second foil(s), an anti-fungus and anti-algae agent is added, and the (first) foil then is subjected to a treatment diminishing the size of the pores of the material sufficiently to meet the existing requirements. The invention also includes a foil assembly with which the methods mentioned are preferably realised. Such a foil assembly is characterized in that it consists of a strip of a first foil that is dust-proof, water vapour permeable and ventilating, of which the upper edge and the lower edge are attached each to a second strip, along its entire length, each partially overlapping the corresponding second strip the material of which possesses a mechanical strength, which is higher than that of the material of the first foil. It consequently is a composite foil, that, viewed from above, consists of three strips of foil material, the first foil in the middle. In a preferred embodiment, the second foil is one whole sheet, featuring holes that are covered by the first strip which has a width, larger than that of the first strip and larger than the distance between the outer plates of the flat construction. Thus it can be folded around the ends of the outer plates. Preferably, the first foil consists of a non-woven synthetic and the second foil of aluminum, and in case the second foil is placed on the first foil as one strip, the holes in that second foil are a row of slots, lengthwise orientated. The invention also includes a flat construction of synthetic material as mentioned above, the end openings of which are sealed in a way and with a foil assembly as described. An example of the foil sealing according to the invention is as follows. The openings in the end surface of a flat construction of 'Lexan', as is meant here, were sealed with a first foil of a non-woven polyester with a weight of 25 g/m²; a pore size, that was reduced form about 80 µm to less than 35 µm, by means of after-binding and calendering, so that it was sufficiently dust-proof; it had a thickness of 0.17 mm and a vapour permeability of 550 liter/m²/sec. The first foil was glued, as a strip, to a second foil of aluminum with a thickness of about 40 µm and, including the adhesive, with a total thickness of about 60 µm, it all being covered at the adhering side with siliconated paper or polyethylene foil. The slots in the middle, aligned with a space between them of about 5 mm, are each about 2 cm long and about 3 mm wide. The construction thus sealed was tested during seven days; at temperatures of 20°C and 80°C the construction was exposed to varying pulling strains, because of which a stretch of ½%, respectively 1% was brought about. It turned out that the mechanical properties were not affected after the test, nor was the quality of the attachment of the aluminum to the 'Lexan'. Also, the vapour permeability of the non-woven foil was not affected. Even after a test during a month at a temperature of 40°C and in an atmosphere with a humidity of 100%, no decline of the essential properties was measured. The invention will be further explained at the hand of the drawing, in which: Fig. 1 is a front view, in perspective, of a flat construction as meant in the example given, of which the openings in the end surface have been sealed with a foil assembly according to the invention; Fig. 2 is a view from above on the side of the foil assembly which is placed over the openings when in use. In Fig. 1, 1 is the flat construction that consists of two outer plates 2 and 3, one on top, one on the bottom, with the distance-bars 4 in between. The channels formed, 5, discharge in the end surface 6 with roughly rectangular openings 7. These openings 7 are sealed with a foil 8, for instance of aluminum, which is placed over the openings 7 by folding the parts 9 around the outer plates 2 and 3, and then glueing them to these plates. This foil 8 contains holes 10, which in the given example are constructed as a row of slots. The openings 7 of each of the channels 5 discharge under at least one of the holes 10. Under each of the holes 10, and therefore over at least a part of every opening 7, lies a first foil 11 meeting the demands: dust-proof, vapour permeable and ventilating. Fig.2 shows in detail the foil assembly, of which the vapour-permeable etc. foil 11 is placed over the holes 10 in advance and is glued in that position. The width of the - second - foil 8 is larger than the distance between both outer plates 2 and 3, so that folding a border part 9 over the outer plates is always possible. These parts 9 are attached (glued) to the outer sides of the outer plates 2 and 3. In order to simplify applying the foil - a combination of the first and second foil, thus forming the situation drawn, may be pre-assembled: foil 8 is generally provided, on its back side, with an adhesive layer, over which, for protection, siliconated paper or a polyethylene foil is placed, which can be pulled off.

Claims: 1. Method for the sealing of the openings (7) in the end surfaces (6) of a flat construction consisting of two or more outer plates (2, 3) of synthetic material, which are mainly flat and which run mainly parallel to each other and are connected to each other by means of spacer bars (4), which bars are placed roughly an even distance from one another and run along the total length of the construction, characterized in that a dust-proof, water-vapour permeable and ventilating first foil (11) is placed over every opening (7), wholly or partly covering it, and that on top of that are placed one or more strips of a second foil (8), the border parts (9) of which are folded around the outer plates (2, 3), and are attached to these outer plates, such that every opening (7) discharges, at least partially, under a part of the first foil (11) which is not covered by the second foil (8). 2. Method according to claim 1, characterized in that on top of the first foil one strip of the second foil (8) is applied, provided with holes (10), placed in such a way that after its attachment every opening (7) discharges under at least one hole (10), and that the back side of every hole (10) is covered totally by the first foil (11). 3. Method according to claim 1 or 2, characterized in that the first foil (11) is a strip which is, lengthwise, applied over all openings (7). 4. Method according to claims 1 and 3, characterized in that two strips of the second foil (8) are applied on respectively upper and lower edge of the strip of the first foil (11), leaving uncovered a part along the middle of the first foil (11). 5. Method according to claims 1, 2, 3 or 4, characterized in that before the foils (8 and 11) are placed over the openings (7), the first (11) and second foil(s) (8) are combined to form a foil assembly, after which the assembly is applied over the openings (7). 6. Method, according to one of the previous claims, characterized in that before the first foil (11), or the combination of foils, is applied over the openings (7), an anti-fungus and anti-algae agent is added. 7. Method according to one of the previous claims, characterized in that the first foil (11) is a 'non-woven' material, which is subject to a treatment that diminishes its pore size. 8. Foil assembly for the realisation of the method according to claim 4, whether or not in combination with one of the methods according to the claims 5, 6, 7, characterized in that it consists of a strip of a first foil (11) which is dust-proof, water vapour permeable and ventilating, of which the upper edge and lower edge are attached each to a strip of a second foil (8), along its entire length, each partially overlapping the corresponding second strip, the material of which possesses a mechanical strength which is higher than that of the material of the first foil. 9. Foil assembly for the realisation of the method according to one of the claims 1 through 3, whether or not in combination, with one of the methods according to the claims 5, 6, 7, characterized in that it consists of a strip of a first foil (11) that is dust-proof, water vapour permeable and ventilating, which strip is attached to a strip of a second foil (8), which strip contains holes (10) that are covered by the first strip, and which has a width larger than that of the first strip and larger than the distance between the outer walls of the outer plates (2, 3) of the flat construction. 10. Foil assembly, according to one of claims 8 or 9, characterized in that the first foil (11) consists of a so-called 'non-woven' material and the second foil (8) of aluminum. 11. Foil assembly according to claims 9 or 10, characterized in that the holes (10) in the second foil (8) are slots, arranged in a row in the middle. 12. Flat construction of synthetic material, consisting of two or more outer plates (2, 3), which are mainly flat and which run mainly parallel to each other and are connected to each other by means of spacer bars (4), which bars are placed on a roughly even distance from one another and run along the total length of the material, characterized in that the openings (10) in the end surfaces are sealed by means of a foil according to claims 8, 9, 10 or 11.

Inventors: HOOFT, JOHANNES WILHELMUS GERARDUS
Applicants: MULTIFOIL B.V.
Application year: 1989
Main classification: E04C2
IPC codes: E04D3, E04C2