EP4035854B1 - Multilayer sound absorption panel and its use and method and device for manufacturing the same - Google Patents

Description

The invention relates to a method for producing multilayer sound absorption panels, each of which has a three-dimensionally structured surface on a cover layer made of wood that has soft and hard sections through mechanical processing. The invention also relates to a multilayer sound absorption panel and its use.

Wooden surfaces are often used in the surface design of furniture and room surfaces. These surfaces are usually closed, i.e. they have no openings, and are therefore not suitable for acoustic effectiveness through sound absorption. In order to make wooden surfaces effective for sound absorption, they are provided with holes, slots or grooves through processing methods such as drilling, milling, slitting, sawing, laser processing or punching. Wooden surfaces opened in this way can be used, for example, for sound-absorbing impact walls in sports halls. In these sound-absorbing impact walls and other applications, the surfaces can be made acoustically transparent (or partially transparent and with material on the back) using perforated or micro-perforated panels, or they can be made sound-absorbing themselves using micro-perforation (with hole diameters of 1 mm or smaller). All previously known methods of opening wooden surfaces have the disadvantage that they make the openings visible to the eye and the The appearance of the surfaces changes significantly compared to closed surfaces.

The term "wooden surfaces" as used here refers to three-dimensional parts, layers or layers of wood, each of which has a visible two-dimensional surface that is the interface between the environment and the respective wood body. "Wooden surfaces" here also include wood veneers or synthetic wood veneers, which in turn are defined as thin sheets of wood with a thickness of 0.25 to 6 mm. The term "top layer" used here refers to the outermost three-dimensional layer of a multi-layer sound absorption board, the two-dimensional surface of which is also the two-dimensional surface of this outermost layer of the multi-layer sound absorption board.

A multilayer sound absorption panel according to the preamble of claim 6 and a method for its production according to the preamble of claim 1 are known from the utility model DE 299 11 495 U1 known. In this multi-layer sound absorption panel, the wooden top layer, which has a thickness of less than about 1.5 mm, is provided with holes that run through to the next layer, which can be microperforations with a diameter in the range of about 0.1 mm to about 1.1 mm, which can be produced by punching, laser processing or drilling and arranged in rows in a grid of 5 mm. The top layer can be a wood veneer that is firmly bonded to the next layer, which forms a supporting layer, by gluing or bonding. A further layer is attached to the back of the supporting layer, which consists of a thin hardboard and also has perforations. This sound absorption panel can be used as wall or ceiling paneling. However, it can also be used as door and cupboard cladding and as a free-standing screen. Despite the relatively small diameter of the micro-perforations, they are easily visible to the naked eye and therefore disrupt the appearance of the wood surface. The disruptive effect of the micro-perforations on an observer is further increased by the regular distribution of the micro-perforations. In addition, the introduction of the micro-perforations into the top layer by punching or laser processing is complex.

It is known in practice to brush wooden surfaces using rotary brushes, whereby soft sections of the wood, such as early wood, are removed by brushing and hard sections of the wood, such as late wood, are left standing, thus creating an aesthetically pleasing three-dimensional structure of the wooden surface.

From the EN 10 2009 058 386 A1 A wooden construction panel for ceilings or walls of a room is known. This should have gaps for the accommodation of sound absorption material, which is incorporated into a carrier layer. The wooden construction panel has a visible layer with openings. The known wooden construction panel is characterized by the fact that the visible layer has a strongly structured surface on its visible side facing the room for diffuse scattering of the reflected sound and that at least a large number of the openings provided in the visible layer reach deep into the sound absorption material.

The object of the invention is to further develop the method for producing a multilayer sound absorption panel according to the preamble of claim 1 in such a way that the three-dimensional structure of the surface of the panel is produced in a way that gives the viewer a visually appealing, essentially undisturbed appearance of the surface wood structure of the cover layer of the board, requires less effort than conventional methods and guarantees that the board continues to have good sound absorption capacity. Furthermore, a sound insulation board according to the preamble of claim 9 is to be specified, which is characterized by the improved properties due to the production according to the invention. In addition, a device for carrying out the method according to the invention and preferred uses for the sound absorption board according to the invention are to be specified.

The object of the invention is achieved by a method according to claim 1, a sound absorption panel according to claim 6 and a use according to claim.

Advantageous further training can be found in the respective sub-claims.

In order to make wooden surfaces sound-absorbing, the surface must be acoustically opened. To this end, the invention proposes that wooden surfaces such as wood veneers be prepared using a special processing method so that the surface is acoustically opened in the "soft" areas by removing wood cells (mainly early wood cells in softwood) using mechanical processing and by opening and enlarging the vessels in the wood (tracheae, pores in hardwood). Various brushing methods are possible for this, or the processing is carried out by embossing the veneer using punching, rolling or milling. This results in a surface that retains the natural structure of the wood and is nevertheless acoustically open or partially opened. The Bear line There is a certain variation in the parameters of the veneer (perforated area proportion and perforated area geometry), depending on the natural growth of the veneer, etc. One advantage of the processing is that it is significantly easier to accomplish than creating a perforation by drilling, slitting or punching. This opens up economic advantages of the invention. Another advantage is that the surface has a typical wood appearance, where the opening in the surface is not or significantly less visible than is the case with other forms of perforation (such as micro-perforation).

The approach of obtaining acoustically transparent or semi-transparent wood surfaces by mechanical processes other than sawing or drilling is advantageous.

If this opened veneer is applied to a carrier plate that is either sound-transparent itself due to larger holes or that is porous and self-absorbing, a sound-absorbing component is created that visually has the impression of a wooden surface. The acoustic effectiveness can be that of a micro-perforation or an acoustically transparent or semi-transparent slotted surface, which, together with the perforated or absorbing layers behind it, forms a sound absorber, whereby these layers can also serve as a carrier material for the veneer.

Possible materials for the surface are veneers made of hardwood, softwood or grasses with a thickness of 0.25 to 6 mm. The processing methods are mechanical processing by brushing, e.g. rotary brushes made of steel, stainless steel, Brass, nylon etc. or veneer embossing by punching, rolling or milling.

Possible carrier materials are drilled, milled or punched wood-based panels such as chipboard, fiberboard or solid wood panels, soft fiberboard, honeycomb panels, foams, wood foams or a frame construction. A sound-absorbing layer made of mineral wool or other materials can be arranged behind the carrier panel, or the carrier panel itself is sound-absorbing or it is additionally combined with absorbent material placed behind it.

Another alternative is to use wood-based panels that are brushed on one side and drilled, milled or slotted on the back, so that the material panel is acoustically opened.

The multilayer sound absorption panels according to the invention can be used as wall and ceiling panels, doors, room dividers, in furniture such as seating, cabinets, sideboards, as furniture fronts, etc. or in other applications, not only in buildings, but also in vehicles, ships or aircraft.

The degree of perforation (proportion of open area to total area) should be between 10% and 50% for an acoustically transparent surface. For acoustically semi-transparent surfaces, the degree of perforation should be between 2 and 10%. For an effect through micro-perforated slits, the degree of perforation should be between 0.1 and 2%. The average slit widths should be as small and between 0.05 mm and 6 mm and in the order of magnitude of the thickness of the veneer or smaller. The slot width is additionally limited by the optical appearance and the mechanical stability of the veneer.

• Fig. 1a eine Draufsicht auf die Oberfläche der aus Holz bestehenden Deckschicht eines Abschnittes einer erfindungsgemäßen mehrschichtigen Schallabsorptionsplatte, wobei das Holz der Deckschicht das einer ersten Holzart ist und mechanisch bearbeitet wurde, um die Deckschicht an den weichen Stellen des Holzes bis zur nächsten Schicht hin zu durchbrechen, so dass auf die Deckschicht auftreffende Schallwellen durch die Durchbrechungen hindurch in die nächste Schicht vordringen können;
• Fig. 1b eine Darstellung der in den Figuren 1a, 1c und 1d verwendeten unterschiedlichen grafischen Muster für die Kennzeichnung von in diesen Figuren dargestellten weichen und harten Stellen im Holz der Deckschicht und der nächsten Schicht;
• Fig. 1c eine Ansicht eines Querschnittes des in Fig. 1a dargestellten Plattenabschnittes entlang der Linie A-A in Fig.1a, wobei die gleichen grafischen Muster zur Kennzeichnung von weichen und harten Stellen im Holz der Deckschicht und der nächsten Schicht verwendet wurden;
• Fig. 1d einen vergrößerten Ausschnitt aus der in Fig. 1c gezeigten Querschnittsansicht, wobei der Ausschnitt durch eine rechteckige Umrahmung in Fig. 1c hervorgehoben ist; und
• Fig. 2a bis 2c entsprechende Darstellungen wie in den Fig.1a bis 1d, wobei jedoch die Deckschicht aus einer von der ersten Holzart optisch verschiedenen zweiten Holzart besteht, der in Fig. 2c dargestellte Querschnitt längs der Linie B-B in Fig. 2a gelegt ist und der in Fig. 2d dargestellte vergrößerte Ausschnitt durch eine rechteckige Umrahmung in Fig. 2c hervorgehoben ist.

The invention will now be explained in more detail with reference to the following description and the accompanying drawings of an embodiment. In the drawings,

• Fig. 1a a plan view of the surface of the wooden cover layer of a section of a multilayer sound absorption panel according to the invention, wherein the wood of the cover layer is that of a first type of wood and has been mechanically processed in order to break through the cover layer at the soft spots of the wood up to the next layer, so that sound waves striking the cover layer can penetrate through the breaks into the next layer;
• Fig. 1b a representation of the Figures 1a, 1c and 1d used different graphic patterns to mark the soft and hard spots in the wood of the top layer and the next layer shown in these figures;
• Fig. 1c a view of a cross section of the Fig. 1a shown plate section along the line AA in Fig.1a , using the same graphic patterns to mark soft and hard spots in the wood of the top layer and the next layer;
• Fig. 1d an enlarged section of the Fig. 1c shown cross-sectional view, where the section is surrounded by a rectangular frame in Fig. 1c highlighted; and
• Fig. 2a to 2c corresponding representations as in the Fig.1a to 1d , but the top layer consists of a second type of wood that is optically different from the first type of wood, which Fig. 2c shown cross section along the line BB in Fig. 2a and which is in Fig. 2d shown enlarged section by a rectangular frame in Fig. 2c is highlighted.

As in the Figures 1a to 1c shown, a sound absorption panel 1 according to the invention consists of a thin, sound-permeable cover layer 2 made of a wood veneer and a sound-absorbing next layer 3, which is a supporting layer made of a suitable carrier material that gives the sound absorption panel 1 additional stability and is firmly connected to the cover layer, e.g. by gluing or bonding. A further layer or layers (not shown) can be attached to the back of the next layer 3. The wood of the cover layer 2 has hard sections 4 and soft sections 5, with the hard sections 4 consisting of late wood and the soft sections 5 of early wood. By mechanical processing, such as by brushing the visible surface of the cover layer 2 using a rotary brush (not shown), a large part of the soft sections 5 of the wood is brushed away, so that openings 6 are created that penetrate the cover layer 2 and extend to the next layer 3. The visible surface of the sound-absorbing panel 1 is given a three-dimensional surface structure by the perforations 6 created by brushing and the hard sections 4 left behind, such as the Figures 1a and 1d show. From the Fig. 1a In the plan view of the surface of the sound absorption panel 1 shown, it can be seen that in those places where soft wood sections 5 were brushed away and as a result, openings 6 were created up to the next layer 3 are, the surface of the next layer 3 is visible. The openings 6 correspond in the plan view essentially in shape, course, width and length to the previously soft sections 5 of the wood, resulting in an appearance of the brushed wood surface that hardly differs from the typical wood appearance of the still untreated wood surface. The sound impinging on the wood surface of the sound absorption panel 1 passes through the openings 6 in the cover layer 2 and penetrates into the next layer 3, where it is absorbed.

As already mentioned, the Figures 2a to 2d The sound absorption panel 8 shown is only made of a different (second) type of wood than that of the cover layer 2, used for the cover layer 9. This other type of wood has a larger proportion of hardwood in the form of hard sections 10 and less softwood in the form of soft sections 12 than the first type of wood. The softwood sections 12 are located in straight or curved narrow strips between the hardwood sections 10. Furthermore, in the Figures 2a to 2d a type of wood with knots 11 is shown as an example. Of course, such knots 11 can also occur in the first type of wood. Sound-permeable openings 13 through the cover layer 9, which is also formed by a wood veneer, extend to the next layer 14, which is sound-absorbing and firmly connected to the cover layer 9. With this type of wood, too, the processing of the wood surface by brushing away soft spots 12 or pores (tracheae) made of soft wood with a rotary brush results in a three-dimensional surface structure of the sound absorption panel 8, as Fig. 2b and Fig. 2d The brighter stripes of the top view in Fig. 2b are the openings 13 created by brushing away, which reveal the underlying supporting layer 14. In this sound absorption panel 8, too, the The typical wood appearance of the untreated top layer differs only insignificantly from the appearance of the brushed top layer 9.

Of course, the invention is not limited to the embodiments shown and the types of wood used. The above description is therefore not to be regarded as restrictive, but as explanatory. The following claims are to be understood in such a way that a named feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. If the claims and the above description define "first" and "second" embodiments, this designation serves to distinguish between two similar embodiments without establishing a priority.

Claims (14)

1. Method for producing a multilayer sound absorption panel (1; 8) comprising at least one carrier panel (3, 14) and a cover layer (2; 9), which is made of wood or artificial wood and which is arranged on the carrier panel, a structured surface being produced at the cover layer (2; 9) on the sound absorption panel, characterized in that the wood of the cover layer has soft and hard portions (4, 5; 10, 11, 12) and the structured surface is produced by only removing soft portions (5; 12) of the wood by means of brushing so that the cover layer (2; 9) is perforated all the way to the carrier panel (3; 14).
2. Method according to claim 1, characterized in that the cover layer (2; 9) is glued to the carrier panel (3; 14) before or after it is or has been mechanically processed by means of brushing.
3. Method according to any one of claims 1 to 2, characterized in that the carrier panel (3; 14) is provided with recesses which contain or consist of holes, grooves, slits or slots.
4. Method according to any one of claims 1 to 3, characterized in that the holes, grooves, slits or slots have a cross-section which is different from the cross-section of the perforations in the wood of the cover layer (2; 9).
5. Method according to any one of claims 1 to 4, characterized in that the carrier panel (3; 14) is sound-absorbing and/or is connected to a further layer which is sound-absorbing.
6. Multilayer sound absorption panel, comprising at least one carrier panel (3, 14) and a cover layer (2; 9) which is arranged on the carrier panel and which contains or consists of wood or artificial wood and has a structured surface,
   characterized in that
   the wood has soft and hard portions (4, 5; 10, 11, 12) and the structured surface is obtainable by removing soft portions (5; 12) of the wood by means of brushing so that the cover layer (2; 9) is perforated all the way to the carrier panel (3; 14).
7. Multilayer sound absorption panel according to claim 6, characterized in that the cover layer (2; 9) is a wood veneer which is glued to the carrier panel (3, 14).
8. Multilayer sound absorption panel according to any one of claims 6 or 7, characterized in that the cover layer (2; 9) is a wood veneer made of hardwood or softwood or grasses.
9. Multilayer sound absorption panel according to any one of claims 6 to 8, characterized in that the cover layer (2; 9) has a thickness of about 0.25 mm to about 6 mm or
   in that the cover layer (2; 9) has a thickness of about 1.25 mm to about 5 mm.
10. Multilayer sound absorption panel according to any one of claims 6 to 9, characterized in that the carrier panel (3; 14) is sound-absorbing and/or in that the carrier panel (3; 14) is porous.
11. Multilayer sound absorption panel according to any one of claims 6 to 10, characterized in that the carrier panel (3; 14) is permeable to sound and a sound-absorbing layer is arranged behind the carrier panel (3; 14).
12. Multilayer sound absorption panel according to any one of claims 6 to 11, characterized in that the carrier panel (3; 14) is provided with a plurality of holes, grooves, slits or slots which have a cross-section that is different from the cross-section of the perforations in the wood of the cover layer (2; 9).
13. Multilayer sound absorption panel according to any one of claims 6 to 12, characterized in that the carrier panel (3; 14) and/or the sound-absorbing layer contains or consists of mineral wool.
14. Use of a multilayer sound absorption panel according to any one of claims 6 to 13 as a wall or ceiling panel, door, room divider, in furniture, buildings, ships, aircraft or vehicles.

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