EP0575710B1 - Process for the manufacture of a slab shaped sound absorbing element for use under soffits - Google Patents

Abstract

A slab-shaped sound-absorbing element (2) is used for mounting below a ceiling, in particular below the ceiling of a large room or a hall, and is provided with a core layer (5) which consists of a porous fibre material absorbing sound waves. The core layer (5) is provided with a porous lamination (7) at least on one of its flat sides. So that the sound-absorbing element (2) can be disposed of without problems during waste removal, it also being required to be comparable to known sound-absorbing elements as regards its acoustic properties, the core layer (5) consists of raw compressed sheep's wool. The individual fibres (6) of the sheep's wool are bound by a cured binder, in particular synthetic resin, to obtain an inherent stiffness of the core layer (5). <IMAGE>

Description

The invention relates to a method for producing a plate-shaped soundproofing element for mounting below a ceiling, in particular below the ceiling of a large room or a hall. Such a sound insulation element is known for example from DE-U-91 11 178. The element has a core of compressed, bonded glass wool. After the production of this core layer, a glass fiber fleece is attached to each of the two flat sides, which is laminated on the outside with a layer of paint. Although this soundproofing element has satisfactory acoustic properties, the insulation materials present in the core layer pose considerable health risks. In the manufacture of soundproofing elements made of glass fiber fleece or rock wool, a product with a relatively short fiber structure is used, which is why it cannot be ruled out that individual fibers get stuck in the lungs of humans during processing. For this reason, special disposal is usually required for the rock wool fiber material. The dangers mentioned are not quite as pronounced with the fiberglass glass wool, but glass wool is also not harmless as an insulating material, both in terms of health and in terms of disposal.

From JP-A-2 006 653 it is known to produce sound-insulating layers using textile-like substances as the carrier layer, this carrier layer being provided with a coating made of a polyurethane prepolymer. The carrier material can consist of cotton, wool, polypropylene, polyethylene, acrylic, acetate or similar materials. The coated carrier layer is brought into a desired shape under pressure, this molding process is supported by heat or steam supplied from outside. A suitable catalyst can be used to accelerate the reaction. The layer described in JP-A-2 006 653 can serve both the purpose of sound insulation and sound insulation. One speaks of sound insulation only in connection with the reduction of sound transmission from components to neighboring components, adjoining rooms or to the outside area. So z. B. sound insulation in the individual rooms of a building. On the other hand, one speaks of sound insulation if freely moving sound waves are to be absorbed within a room. Only sound insulation changes the room acoustics.

The layer according to JP-A-2 006 653 also poses problems in waste disposal. This is primarily due to the substances contained in the layer, which almost without exception require special disposal measures. This does not change the fact that cotton or wool can be used as the textile fabric, because this is provided with a coating of a polyurethane prepolymer in the course of the process, which in turn results in the above-mentioned problems in disposal.

The invention is therefore based on the object of developing a method for producing a plate-shaped soundproofing element which leads to a soundproofing element which can be disposed of without any problems in the course of waste disposal, the soundproofing element thus obtained with regard to its acoustic properties using the known soundproofing elements, for example on the basis of Rock wool, should be comparable.

• Hineingeben von Fasern aus roher Schafwolle in eine Form zur Herstellung einer Kernschicht,
• Komprimierung der Fasern innerhalb der Form,
• Zugabe eines aushärtbaren Bindemittels, z. B. Kunstharz oder Zellulose, in die Form, hierbei Aufrechterhaltung des Kompressionsdrucks so lange, bis das Bindemittel aushärtet und die einzelnen Fasern bindet,
• Versehen zumindest einer der beiden Flachseiten der so gefertigten eigensteifen Kernschicht mit einer porösen Kaschierung, z. B. einer offenporigen Farbschicht.

To solve this problem , a method is proposed for producing a plate-shaped sound insulation element for mounting below a ceiling, in particular below the ceiling of a large room or hall, using the following individual steps:

• Adding raw sheep's wool fibers into a mold to make a core layer,
• Compression of the fibers within the mold,
• Add a curable binder, e.g. B. synthetic resin or cellulose, in the mold, while maintaining the compression pressure until the binder hardens and binds the individual fibers,
• Provide at least one of the two flat sides of the self-rigid core layer thus produced with a porous lamination, for. B. an open-pore paint layer.

The invention is based on the knowledge that sheep wool has a distinctly good acoustic insulation behavior which, according to initial estimates, is no worse than when using rock wool or glass wool. With regard to the problems with waste disposal, sheep's wool, on the other hand, is far superior to the two known materials, since it is a purely natural product which is subject to a natural decomposition process as waste. The individual fibers are much longer than with rock wool and glass wool, so that there is no significant risk of the fibers getting stuck in the human lungs.

However, compressed sheep's wool does not have its own stiffness, which is why the invention proposes to bind the individual fibers of the sheep's wool in order to achieve an inherent stiffness in the core layer. This is done using a hardening binder. The binder is placed in the sheep wool compressed in a mold, the compression pressure being maintained until the binder binds the individual wool fibers. This creates an inherently stable plate, which is then provided with a porous lamination.

The inherent stability of the plate or core layer can be further increased by adding 10 to 25 percent, preferably about 20 percent, by volume to the sheep's wool. Like sheep's wool, cotton is a renewable natural substance. The binder should also be made on a natural basis. According to one embodiment of the invention, it is therefore proposed that the binder consist of synthetic resin.

In order to keep the lamination largely free of environmentally harmful substances, it is also proposed that the lamination consist of an open-pore water-based paint layer.

Finally, an embodiment of the soundproofing element is characterized in that fastening elements are anchored in the core layer. This eliminates the need for additional measures to attach the fastening elements required for the arrangement of the sound insulation element below the ceiling to the outer surface of the sound insulation element.

Fig. 1

In einer Schnittdarstellung ein plattenförmiges Schalldämmelement sowie dessen Befestigung unterhalb einer Raumdecke und

Fig. 2

in drei Teilschnitten unterschiedliche Arten der Anordnung plattenförmiger Schalldämmelemente unterhalb einer Raumdecke.

Further details and advantages result from the following description of the accompanying drawing, in which preferred embodiments of plate-shaped soundproofing elements are shown for mounting below a ceiling. The drawing shows:

Fig. 1

In a sectional view, a plate-shaped soundproofing element and its attachment below a ceiling and

Fig. 2

in three partial sections different types of arrangement of plate-shaped sound insulation elements below a ceiling.

Fig. 1 shows a sound insulation element 2 to be arranged below a ceiling in the form of a plate or baffle. Fig. 2 shows that several rows of such soundproofing elements 2 are provided, each row in turn being composed of several soundproofing elements 2 arranged one behind the other. The type of arrangement of the sound insulation elements 2 below a ceiling 1 can be chosen depending on the acoustic requirements. In the arrangement shown on the left in FIG. 2, the individual sound insulation elements 2 hang vertically downwards, while in the middle representation of FIG. 2 the sound insulation elements 2 are fastened horizontally under the ceiling 1 by means of rails 3. In the right representation of FIG. 2, the individual soundproofing elements 2 are suspended obliquely with the aid of guy wires 4.

Details of the sound insulation elements 2 are shown in FIG. 1. The soundproofing element 2 has a core layer 5, which consists primarily of raw, compressed sheep's wool. The individual fibers 6 of the sheep's wool are bound by a hardened binder. Synthetic resin is used as the binder, which, in the hardened state, gives the core layer 5 such stability that it is inherently stable and the individual soundproofing elements 2 can therefore also be mounted firmly in a horizontal arrangement below a ceiling.

When producing the sound insulation elements 2, the raw, i.e. Unwoven sheep's wool placed in a rectangular shape and compressed therein. Synthetic resin is then added, the compression pressure being maintained until the synthetic resin binds the individual wool fibers. This creates an inherently stable plate, which is then provided on one or both flat sides with a porous lamination 7 in the form of an open-pore water-based paint layer. Such porous lamination is also possible at the edges if the hygienic requirements are met.

The sound insulation element 2 designed in this way absorbs sound waves very well, the liner 7 being open-pored Structure hardly affects the acoustic insulation effect of the core layer 5 made of sheep's wool. The lamination 7, however, makes it easy to maintain the surface of the sound-absorbing element 2, so that in addition to an application in industrial production halls, it can also be used in large laboratory rooms or kitchens. Since sheep's wool is a long-fiber product made from a renewable natural material, the soundproofing element 2 does not pose any health risks. Sheep wool is also naturally degradable. Another advantage of sheep's wool is that it tolerates a relatively large amount of moisture without aging. The lamination 7 also provides the soundproofing element 2 with sufficient resistance to infestation by mold and bacteria.

In Fig. 1 it is shown that in the upper narrow side of the soundproofing element 2, a fastening element 8 designed in the manner of a helical spring is embedded. The supply element 8 can subsequently be screwed into the sound insulation element 2, but it can also be inserted during the manufacture of the sound insulation element 2 and then anchored in the core layer 5 during the hardening process. The supply element 8 is provided at its upper end with a hook 9 which is suspended in an angular plate 11 slidably arranged on a T-rail 10. The T-rail 10 is fastened either directly or at a distance below the ceiling and can also be embedded in it if sufficient space is left for inserting the plate elements 2.

To achieve an inherent stability of the sound insulation element 5 synthetic resin is used as a binder for binding the individual fibers of the core layer. Cellulose can also be used as a binder. In view of the natural degradability, synthetic resin is preferred. The inherent stability can be further increased by adding cotton to the sheep's wool in a volume fraction of approx. 20 percent.

Reference list

1

ceiling

2nd

Soundproofing element

3rd

rail

4th

Guy

5

Core layer

6

fiber

7

Lamination

8th

Fastener

9

hook

10th

T-rail

11

Angle plate

Claims (4)

1. Method for the production of a board-like sound insulation element (2) for mounting underneath a room ceiling, especially underneath the ceiling of a large room or hall, by using the following individual steps:

   - introducing fibres (6) of raw sheep wool into a mould for producing a core layer (5),

   - compressing the fibres (6) within the mould,

   - adding a curable binder, for example synthetic resin or cellulose, into the mould, at the same maintaining the compression pressure until the binder cures and binds the individual fibres (6),

   - providing at least one of the two flat sides of the inherently rigid core layer (5) thus made with a porous coating (7), for example an open-pored paint layer.
2. Method according to Claim 1, characterized in that cotton is added in a proportion by volume of 10 to 25%, preferably approximately 20%, to the core layer (5) before compression.
3. Method according to one of Claims 1 and 2, characterized in that the coating (7) is produced from an open-pored water-based paint layer.
4. Method according to one of Claims 1 to 3, characterized in that fastening elements (8) are anchored in the core layer (5).

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