Acoustic building panel for installation as sound-absorbing ceiling panel and / or sound-absorbing wall panel and method for providing the base layer of an acoustic building panel

Abstract

Acoustic building panel (0) for installation as sound-absorbing ceiling panel and / or sound-absorbing wall panel comprising a base layer (1), wherein said base layer (1) contains the following constituents: wood wool as support material; and a solidified binding agent provided by a solidified suspension comprising a biopolymer and a liquid, preferably a polar liquid, more preferably water; in total to at least 95%, preferably to at least 99%, more preferably to at least 99.7%, most preferably to 100%.

Description

[0001] Knauf Gips KG

[0002] P-KCS-005-WO

[0003] 1

[0004] 5 ACOUSTIC BUILDING PANEL FOR INSTALLATION AS SOUND-ABSORBING CEILING PANEL AND / OR SOUND-ABSORBING WALL PANEL AND METHOD FOR PROVIDING THE BASE LAYER OF AN ACOUSTIC BUILDING PANEL

[0005] The invention refers to an acoustic building panel for installation as soundabsorbing ceiling panel and / or sound-absorbing wall panel and to a method for

[0006] 10 providing the base layer of an acoustic building panel.

[0007] The invention lies in the field of building panels that are installed in interior rooms to influence the room's acoustics.

[0008] To influence the room's acoustics building panels can be installed on the ceiling and walls of the room or suspended from the ceiling. Acoustic building panels are

[0009] 15 known that absorb sound in order to reduce the echo inside the room and thus create a more pleasant ambience in terms of the room acoustics, for example a more quiet room.

[0010] A specific type of acoustic building panels, so called wood wool panels, are known. Such wood wool panels use wood chips (shavings / fibres) as support material.

[0011] 20 These wood chips are mixed with a mineral binding agent such as caustic magnesite. The resulting mixture is shaped according to the required board dimensions into a layer with appropriate length, width and thickness. After solidifying the binding agent, which can comprise a baking at elevated temperatures with or without additional pressing, a solid wood wool panel is

[0012] 25 provided.

[0013] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0014] P-KCS-005-WO

[0015] 2

[0016] The disadvantage of these known acoustic building panels is that they have a high embodied environmental impact, i.e., the production and disposal of such building panels involves significant environmental impact.

[0017] It is the objective of the present invention to overcome the disadvantages of the

[0018] 5 prior art by providing an improved acoustic building panel that has a low embodied environmental impact, and by providing an improved method for providing the base layer of such an improved acoustic building panel.

[0019] This objective is solved by the acoustic building panel and the method according to the respective independent claim. The dependent claims concern advantageous

[0020] 10 aspects of the invention.

[0021] The invention comprises an acoustic building panel for installation as soundabsorbing ceiling panel and / or sound-absorbing wall panel comprising a base layer, wherein said base layer contains the following constituents:

[0022] - wood wool as support material; and

[0023] 15 - a solidified binding agent provided by a solidified suspension comprising a biopolymer and a liquid, preferably a polar liquid, more preferably water; in total to at least 95%, preferably to at least 99%, more preferably to at least 99.7%, most preferably to 100%.

[0024] In a preferred way, the solidified suspension consists of the biopolymer and the

[0025] 20 liquid, preferably the polar liquid, more preferably the water.

[0026] The base layer, which contains said constituents in total to at least 95%, results in a very low embodied environmental impact, which decreases continuously until

[0027] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0028] P-KCS-005-WO

[0029] 3 the case in which the base layer contains said constituents in total to (essentially) 100%.

[0030] Preferably, the total thickness of the acoustic building panel perpendicular to its main surface is in the range of 12 to 50 mm, more preferably of 15 to 35 mm, even

[0031] 5 more preferably of 15 to 25 mm. The panel size (width x length) preferably corresponds to 600 mm x 600 mm, 625 mm x 625 mm, 1200 mm x 600 mm, or 1250 mm x 625 mm. Other dimensions are possible as well.

[0032] According to a preferred aspect the biopolymer is native starch or modified starch or native flour or modified flour or any mixture thereof. Preferably, (native or modified) starch or (native or modified) flour is obtained from corn, wheat, potato or rice.

[0033] According to another preferred aspect a ratio of the biopolymer (preferably native starch or modified starch or native flour or modified flour or any mixture thereof) to the wood wool within said base layer is in a range between 20 w.-% and 45 w.-

[0034] 15 %, preferably between 25 w.-% and 40 w.-%, more preferably between 30 w.-% and 35 w.-%. This ensures good bonding of the wood wool by the binding agent.

[0035] According to another preferred aspect a residual water content of the base layer is below 20%, preferably, below 15%, more preferably below 10%. This ensures a sufficient hardness of the resulting acoustic building panel.

[0036] According to another preferred aspect said wood wool consists of wood chips with a length-to-width ratio of at least 50:1 , preferably of at least 100:1 , more preferably of at least 250:1 .

[0037] According to another preferred aspect said wood wool consists of wood chips with a length in a range between 5 cm and 25 cm, preferably between 8 cm and 20 cm,

[0038] 25 more preferably between 10 cm and 15 cm. Preferred wood chips of the wood wool

[0039] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0040] P-KCS-005-WO

[0041] 4 have a width of 1 to 4 mm and a thickness of 0.2 to 0.5 mm. The wood wool chips are irregularly distributed within the wood wool panel in the form of a three- dimensional framework bonded together, at least in sections, by the solidified binding agent.

[0042] 5 According to another preferred aspect at least one surface of the acoustic building panel is coated with a fire resistive coating. Preferably, the fire resistive coating comprises phosphate, urea, acetic acid or any mixture thereof. These substances serve as fire retardant. By that the acoustic panel can be adapted to comply with the relevant fire protection regulations, specifically to the to the classification

[0043] 10 Euroclass "B-s2, dO" according to EN 13501 -1 (DIN EN 13501 -1 :2019-05).

[0044] According to another preferred aspect the acoustic building panel has a weighted sound absorption coefficient of at least aw= 0.60, preferably of at least aw= 0.68, more preferably of at least aw= 0.75. The weighted sound absorption coefficient is the capability of the acoustic building panel to absorb sound and is measured

[0045] 15 and defined as in ISO 1 1654 in the version effective on the filing date of this application.

[0046] According to another preferred aspect the acoustic building panel has a weight- by-volume smaller than 300 kg / m3, preferably smaller than 250 kg / m3, more preferably smaller than 200 kg / m3, most preferably smaller than 150 kg / m3.

[0047] 20 Therefore, this preferred acoustic building panel is about 30% lighter than known acoustic building panels using magnesite as binding agent. A lightweight acoustic building panel can be attached more easily to the ceiling or wall.

[0048] According to another preferred aspect the acoustic building panel is a multi-layer panel comprising the base layer and an additional layer. Such additional layer can

[0049] 25 take over a functional task, such as providing additional acoustic damping, increasing or decreasing air permeability, or providing a smooth surface finish.

[0050] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0051] P-KCS-005-WO

[0052] 5

[0053] A first preferable such additional layer contains the following constituents:

[0054] - wood wool as an additional support material; and

[0055] - an additional solidified binding agent comprising an additional biopolymer and water;

[0056] 5 in total to at least 95%, preferably to at least 99%, more preferably to at least 99.7%, most preferably to 100%. Thereby said wood wool of the additional second support material consists of wood chips with a length in a range between 0.1 mm and 4 mm, preferably between 0.3 mm and 2.5 mm, more preferably between 0.5 mm and 2.0 mm. Such a multi-layer acoustic building panel has low embodied

[0057] 10 environmental impact and a smooth surface finish for beneficial visual room design. Preferably the binding agent of the additional layer is the same as the binding agent of the base layer.

[0058] A second preferable such additional layer is a nonwoven based on glass fibre, especially on cellulose-glass fibre, or paper, characterized in that the nonwoven based on glass fibre, especially cellulose-glass fibre, or paper has an airflow resistivity o (ISO 9053-1 :2018) of at least 1.00 103Pa s / m2. The nonwoven serves as an additional sound absorber, whereby the airflow resistivity o is a parameter that influences the sound absorption, and that can be used to characterize it.

[0059] Preferably, the nonwoven based on glass fibre, especially cellulose-glass fibre, or

[0060] 20 paper is a nonwoven according to the definition in EN 29092 (DIN EN 29092:1992- 08). Preferably the glass fibre nonwoven is firmly and durably bonded by an adhesive to the wood wool base layer.

[0061] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0062] P-KCS-005-WO

[0063] 6

[0064] A third preferable such additional layer is provided by a method comprising the steps:

[0065] - providing a mixture by mixing an additional support material, an additional binding agent, and an air-entraining agent; and

[0066] 5 - forming said additional layer from said mixture on said base layer or on another additional layer.

[0067] The air-entraining agent can comprise a surfactant and has the effect that the permeability to air of said additional layer (and therefore also of said acoustic panel as a whole) is enhanced by reducing its airflow resistivity. By using the air¬

[0068] 10 entraining agent the solidified binding agent of the additional becomes porous. In this case the additional binding agent can comprise a biopolymer and water which is later solidified.

[0069] According to another preferred aspect the every additional layer has a thickness in a range between 2 mm and 8 mm, preferably between 3 mm and 7 mm, more preferably between 5 mm and 6 mm.

[0070] According to another preferred aspect the acoustic building panel is a single-layer panel. A single-layer panel is cheaper and easier to produce.

[0071] In addition, the invention comprises a method for providing the base layer of an acoustic building panel as described above comprising the steps:

[0072] 20 - providing wood wool, (native and / or modified) starch and / or (native and / or modified) flour and water;

[0073] - mixing the (modified) starch and / or the (modified) flour and the water at a mixing temperature below the gelatinization temperature of the (modified)

[0074] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0075] P-KCS-005-WO

[0076] 7 starch and / or the (modified) flour, preferably at a mixing temperature below 60°C, more preferably below 50°C, most preferably at room temperature to form the binding agent;

[0077] - providing a base mixture by mixing the wood wool with the binding agent;

[0078] 5 - forming said base mixture to a layer;

[0079] - heating said formed layer to an oven temperature in a range between 200°C and 500°C, preferably in a range between 200°C and 400°C, more preferably in a range between 250°C and 350°C, for a drying time period that is chosen such that a residual water content of the acoustic building

[0080] 10 panel is below 20%, preferably, below 15%, more preferably below 10%.

[0081] In order to heat the layer to an oven temperature, the layer can be transferred to an oven. With this method, specifically by heating the layer to the oven temperature, it is ensured that the (modified) starch and / or the (modified) flour in the base mixture has reached the gelatinisation temperature to a sufficient degree, preferably completely, for a good binding effect of the wood wool. Also it is ensured, that while heating to the oven temperature the base layer is not heated too high in order not to get burnt.

[0082] In the following, the invention is described in connection to drawings, where:

[0083] Fig. 1 shows a schematic cross section of a preferred single-layer acoustic

[0084] 20 building panel; and

[0085] Fig. 2 shows a schematic cross section of a preferred multi-layer acoustic building panel with a base layer and one additional layer.

[0086] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0087] P-KCS-005-WO

[0088] 8

[0089] Fig. 1 shows a schematic cross section of a preferred single-layer acoustic building panel 0. The only layer of this acoustic building panel 0 is the base layer 1 , which is essentially made only of wood wool as support material and a solidified binding agent comprising modified wheat flour and water.

[0090] 5 This acoustic building panel 0 is provided by a method comprising the steps:

[0091] - providing wood wool, modified wheat flour and water;

[0092] - mixing the modified wheat flour and water at a mixing temperature that equals the room temperature of 25°C to form the binding agent;

[0093] - providing a base mixture by mixing the wood wool with the binding agent;

[0094] 10 - forming said base mixture to a base layer 1 ;

[0095] - transferring said formed base layer 1 to an oven;

[0096] - heating said formed base layer 1 to an oven temperature of 350°C for a drying time period that is chosen such that a residual water content of the acoustic building panel 0 is below 20%.

[0097] 15 The wood wool consists of wood chips with a length that is distributed in a range between 8 cm and 20 cm, a width that is distributed in a range between 1 to 4 mm and a thickness that is distributed in a range between 0.2 to 0.5 mm. The wood wool chips are irregularly distributed within the wood wool panel 0 in the form of a three-dimensional framework bonded together, at least in sections, by the

[0098] 20 solidified binding agent, whereby the ratio of modified flour to wood wool within the base layer 1 is 30 w.-%, which ensures good bonding of the wood wool by the binding agent.

[0099] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0100] P-KCS-005-WO

[0101] 9

[0102] This biopolymer-based wood wool acoustic building panel 0 is significantly lighter than known acoustic building panels using magnesite as binding agent. In the depicted embodiment of the acoustic building panel 0 according to the invention its weight-by-volume is 280 kg / m3and by lowering the water content even more

[0103] 5 can be even lighter.

[0104] Fig. 2 shows a schematic cross section of a preferred multi-layer acoustic building panel 0 with the same base layer 1 as in Fig. 1 and one additional layer 2.

[0105] This acoustic building panel 0 is provided by a method comprising the steps:

[0106] - providing wood wool, modified wheat flour and water;

[0107] 10 - mixing the modified wheat flour and water at a mixing temperature that equals the room temperature of 25°C to form the binding agent;

[0108] - providing a base mixture by mixing the wood wool with the binding agent;

[0109] - forming said base mixture to a base layer 1 ;

[0110] - providing a mixture by mixing an additional support material, an additional

[0111] 15 binding agent, and an air-entraining agent; and

[0112] - forming said additional layer 2 from said mixture on said base layer 1 ;

[0113] - transferring said formed layers 1 , 2 to an oven;

[0114] - heating said layers 1 , 2 to an oven temperature of 350°C for a drying time period that is chosen such that a residual water content of the acoustic

[0115] 20 building panel 0 is below 20%, e.g. for a drying time period of 10 min.

[0116] Received at EPO via Web-Form on Aug 28, 2024 Knauf Gips KG

[0117] P-KCS-005-WO

[0118] 10

[0119] In this embodiment the binding agent of the additional layer 2 is the same as the binding agent of the base layer 1 .

[0120] In the depicted embodiment the base layer 1 has a thickness of 25 mm and the additional layer 2 has a thickness of 5 mm. In an alternative embodiment the base

[0121] 5 layer 1 can also have a thickness of 15 mm.

[0122] Received at EPO via Web-Form on Aug 28, 2024

Claims

Knauf Gips KGP-KCS-005-WO115 Claims1. Acoustic building panel (0) for installation as sound-absorbing ceiling panel and / or sound-absorbing wall panel comprising a base layer (1 ), wherein said base layer (1 ) contains the following constituents:- wood wool as support material; and10 - a solidified binding agent provided by a solidified suspension comprising a biopolymer and a liquid, preferably a polar liquid, more preferably water; in total to at least 95%, preferably to at least 99%, more preferably to at least 99.7%, most preferably to 100%.

2. Acoustic building panel (0) according to claim 1 , wherein the biopolymer is native starch or modified starch or native flour or modified flour or any mixture thereof.

3. Acoustic building panel (0) according to claim 1 or 2, wherein within said base layer (1 ) a ratio of the biopolymer to the wood wool is in a range between 20 w.-% and 45 w.-%, preferably between 25 w.-% and 40 w.-%, more preferably20 between 30 w.-% and 35 w.-%.

4. Acoustic building panel (0) according to anyone of the preceding claims, wherein a residual water content of the base layer (1 ) is below 20%, preferably, below 15%, more preferably below 10%. ceived at EPO via Web-Form on Aug 28, 2024Knauf Gips KGP-KCS-005-WO125. Acoustic building panel (0) according to anyone of the preceding claims, wherein said wood wool consists of wood chips with a length-to-width ratio of at least 50:1 , preferably of at least 100:1 , more preferably of at least 250:1 .

6. Acoustic building panel (0) according to anyone of the preceding claims,5 wherein said wood wool consists of wood chips with a length in a range between 5 cm and 25 cm, preferably between 8 cm and 20 cm, more preferably between 10 cm and 15 cm.

7. Acoustic building panel (0) according to anyone of the preceding claims, wherein at least one surface of the acoustic building panel (0) is coated with a10 fire resistive coating.

8. Acoustic building panel (0) according to anyone of the preceding claims, having a weighted sound absorption coefficient of at least aw= 0.60, preferably of at least Qw = 0.68, more preferably of at least aw= 0.75.

9. Acoustic building panel (0) according to anyone of the preceding claims, having a weight-by-volume smaller than 300 kg / m3, preferably smaller than 250 kg / m2, more preferably smaller than 200 kg / m3, most preferably smaller than 150 kg / m3.

10. Acoustic building panel (0) according to anyone of the preceding claims, wherein the acoustic building panel (0) is a multi-layer panel comprising the20 base layer (1 ) and an additional layer (2), wherein said additional layer (2) contains the following constituents:- wood wool as an additional support material; and- an additional solidified binding agent comprising an additional biopolymer and water; ceived at EPO via Web-Form on Aug 28, 2024Knauf Gips KGP-KCS-005-WO13 in total to at least 95%, preferably to at least 99%, more preferably to at least 99.7%, most preferably to 100%, and wherein said wood wool of the additional second support material consists of wood chips with a length in a range between 0.1 mm and 4 mm, preferably between 0.3 mm and 2.5 mm, more5 preferably between 0.5 mm and 2.0 mm.1 1. Acoustic building panel (0) according to anyone of the preceding claims, wherein the acoustic building panel (0) is a multi-layer panel comprising the base layer (1 ) and an additional layer (2), wherein said additional layer (2) is a nonwoven based on cellulose-glass fibre or paper, characterized in that the10 nonwoven based on cellulose-glass fibre or paper has an airflow resistivity o (ISO 9053-1 :2018) of at least 1 .00 103Pa s / m2.

12. Acoustic building panel (0) according to anyone of the preceding claims, wherein the acoustic building panel (0) is a multi-layer panel comprising the base layer (1 ) and an additional layer (2), wherein said additional layer (2) is provided by a method comprising the steps:- providing a mixture by mixing an additional support material, an additional binding agent, and an air-entraining agent; and- forming said additional layer (2) from said mixture on said base layer (1 ) or on another additional layer (2).20 13. Acoustic building panel (0) according to anyone of the claims 10 - 12, wherein every additional layer (2) has a thickness in a range between 2 mm and 8 mm, preferably between 3 mm and 7 mm, more preferably between 5 mm and 6 mm.

14. Acoustic building panel (0) according to anyone of the claims 1 - 9, wherein the acoustic building panel (0) is a single-layer panel. ceived at EPO via Web-Form on Aug 28, 2024Knauf Gips KGP-KCS-005-WO1415. Method for providing the base layer (1 ) of an acoustic building panel (0) according to anyone of the preceding claims comprising the steps:- providing wood wool, starch and / or flour and water;- mixing the starch and / or the flour and the water at a mixing temperature5 below the gelatinization temperature of the starch and / or the flour, preferably at a mixing temperature below 60°C, more preferably below 50°C, most preferably at room temperature, to form the binding agent;- providing a base mixture by mixing the wood wool with the binding agent;- forming said base mixture to a layer; io - heating said formed layer to an oven temperature in a range between 200°C and 500°C, preferably in a range between 200°C and 400°C, more preferably in a range between 250°C and 350°C, for a drying time period that is chosen such that a residual water content of the acoustic building panel (0) is below 20%, preferably, below 15%, more preferably below 10%.15 ceived at EPO via Web-Form on Aug 28, 2024

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