SOUND INSULATION BOARD MADE OF MINERAL WOOL, AND MANUFACTURING METHOD OF SUCH A BOARD

Description

[0001] The invention relates to a mineral wool panel for use as an acoustic panel, for example in a suspended ceiling system.

[0002] Document EP 1 743 076 discloses a mineral wool acoustic panel which is creped then split in the thickness and sanded. The front face (the one intended to be turned towards the side from which the sound to be dampened comes) is the cut and sanded face, which comes from the center of the panel before cutting. The fibers on this surface and near this surface have a preferential orientation in the Z direction. The sound absorption α W is greater than or equal to 0.7. Cutting in the thickness and sanding are steps which increase the manufacturing time and which are a source of waste production, which results in costs.

[0003] There is therefore a need for a panel made without cutting which has equally good, or even better, acoustic properties.

[0004] For this, the invention provides a mineral wool panel intended to be used as an acoustic panel according to claim 1.

[0005] According to another characteristic, the panel has a micron count between 2.5 / 5g and 6 / 5g, preferably between 3 / 5g and 6 / 5g, or even between 3.5 / 5g and 6 / 5g, or between 4 / 5g and 5 / 5g, or a metric count between 200 and 300, preferably between 200 and 290, or even between 200 and 280, or between 200 and 270.

[0006] According to another feature, the panel also includes, on each of its main faces, a veil.

[0007] According to another feature, the veil intended to be turned towards the side from which the sound to be dampened originates having a specific resistance to airflow less than or equal to 1 kPa.s / m, preferably less than or equal to 0.5 kPa.s / m, and the opposite veil having a specific resistivity to airflow greater than or equal to 1 kPa.s / m, preferably greater than or equal to 5 kPa.s / m, or even greater than or equal to 10 kPa.s / m, or even airtight.

[0008] According to another feature, the panel comprises a binder mass rate of between 2% and 15% of the total mass, preferably between 2% and 10% of the total mass.

[0009] According to another feature, the panel has an acoustic absorption α W greater than or equal to 0.9.

[0010] According to another feature, the panel has an acoustic insulation D nfw greater than or equal to 38 dB, preferably greater than or equal to 39 dB, or even greater than or equal to 40 dB, or even greater than or equal to 41 dB, or even greater than or equal to 42 dB.

[0011] The invention also relates to a method of manufacturing the mineral wool panel described above, according to claim 8.

[0012] According to another feature, during the manufacturing stage of the glass fiber mat, a combination of parameters is set from at least: ∘ the viscosity of the molten glass, which is between 820 and 1500 poise, preferably between 950 and 1200 poise, ∘ the burner pressure, which is between 200 and 1000 mm CE, preferably between 200 and 600 mm CE, ∘ the total glass output per day and per centrifuge, which is between 14 tonnes / day and 23 tonnes / day, preferably between 17 and 22 tonnes / day, o the number of holes in each centrifuge, which is between 5000 and 40000, preferably between 15000 and 35000, and o the rotation speed of the centrifuge at a speed greater than 2000 rpm.

[0013] According to another particularity, the diameter of the orifices of each centrifuge is between 0.5 and 1.1 mm.

[0014] According to another particularity, each centrifuge has a diameter between 200 and 800 mm.

[0015] Another distinctive feature is that during the rock fiber mat manufacturing stage, a combination of parameters is set from among at least: • the total rock removal per day, which is between 100 and 250 tonnes / day, • the rotation speed of the rotors, which is between 2000 and 4000 rpm.

[0016] Another distinctive feature is that each rotor has a diameter between 150 mm and 350 mm.

[0017] According to another feature, binder is sprayed onto the mineral fibers before they fall onto the receiving mat, with a rate of between 2% and 15% of the total mass, preferably between 2% and 10% of the total mass, the mineral fiber mat being oven-cured, preferably after creping, in order to polymerize the binder.

[0018] Another distinctive feature is that a veil is glued to each of the main faces of the mineral wool panel.

[0019] Furthermore, the panel is not cut in the thickness along a plane substantially parallel to its main faces. This means that it comes directly from the manufacture of mineral wool, and more precisely that none of its main faces is a face resulting from a cut in a block of material of larger volume. The fibers on the surface and near the surface have an orientation preferentially substantially parallel to said face.

[0020] The fact that the panel according to the invention is not split in thickness, contrary to what is known in the prior art, saves production time, material cost and waste management.

[0021] Furthermore, the panel according to the invention has very interesting acoustic properties thanks to its low airflow resistivity (between 30 and 120 kPa.s / m², preferably between 50 and 110 kPa.s / m², or even between 50 and 100 kPa.s / m², or between 50 and 90 kPa.s / m², or even between 50 and 80 kPa.s / m²) and a high Young's modulus (between 0.5 and 4 MPa, preferably between 0.8 and 4 MPa, even more preferably between 1.2 MPa and 4 MPa, or even between 1.5 MPa and 4 MPa, or between 2 MPa and 4 MPa), which make it an ideal candidate for use as an acoustic panel. Indeed, in the ranges mentioned above, the lower the airflow resistivity, the better the sound absorption, and the higher the Young's modulus, the better the sound insulation.

[0022] The surface density of the panel according to the invention, which is greater than or equal to 3.2 kg / m², provides it with satisfactory mechanical strength, which improves further as the surface density increases. Thus, the surface density of the panel according to the invention is preferably greater than or equal to 4 kg / m², or even greater than or equal to 4.5 kg / m², or even greater than or equal to 5 kg / m².

[0023] The measurement of air flow resistivity is carried out according to ISO 9053.

[0024] The measurement of Young's modulus is carried out according to the ISO 18437 standard and according to the article by C. Langlois, R. Panneton and N. Atalla: Polynomial relations for quasi-static mechanical characterization of isotropic poroelastic materials, J. Acoust. Soc. Am., 110:3032-3040, 2001.

[0025] Airflow resistivity and Young's modulus measurements are performed on the panel without the front / back sails.

[0026] The mineral wool panel according to the invention can be made of glass wool, by internal centrifugal fiberization, or of rock wool, by external centrifugal fiberization.

[0027] Mineral fibers are creped at a creping ratio of between 1.5 and 5. The creping ratio has an influence on the airflow resistivity and the Young's modulus. The creping ratio is preferably between 2 and 5, or even between 2.5 and 5, or even between 3 and 5 to further reduce the airflow resistivity and increase the Young's modulus. Indeed, creping promotes the orientation of the fibers in a direction perpendicular Z to the main faces of the panel: the higher the creping ratio, the greater the orientation of the fibers along Z and the more the airflow resistivity is reduced and the Young's modulus increased.

[0028] When the panel is made of glass wool, it also has a micronaire between 2.5 / 5g and 6 / 5g. Preferably, the micronaire is between 3 / 5g and 6 / 5g, or even between 3.5 / 5g and 6 / 5g, or between 4 / 5g and 5 / 5g. Indeed, the higher the micronaire, the lower the airflow resistance and the higher the Young's modulus.

[0029] The micronaire is representative of the fineness of the glass fibers. The micronaire measurement accounts for the specific surface area by measuring the aerodynamic pressure drop when a given quantity of fibers extracted from an unsized mat is subjected to a given pressure of a gas - generally air or nitrogen. This measurement is common in mineral fiber production units, it is carried out according to the DIN 53941 or ASTM D 1448 standard and uses a device called a "micronaire device".

[0030] When the panel is made of rock wool, it also has a fasonaire of between 200 and 300. Preferably, the fasonaire is between 200 and 290, or even between 200 and 280, or even between 200 and 270. In fact, the more the fasonaire decreases, the more the resistivity to air flow decreases and the more the Young's modulus increases.

[0031] The fasonaire is representative of the fineness of rock fibers. The fasonaire measurement is a determination of the fiber fineness index by a method similar to that of the micronaire according to the standards ASTM-D-1448 or DIN 53941. The fasonaire is equal to the pressure drop or difference in flow rate of a gas stream passing through a test piece consisting of a tuft of mineral fibers of given mass (equal to 5 g for the measurements according to the invention). The tuft of fibers, free of binder or any other non-fibrous component, is compressed in a cylindrical chamber of predetermined volume. With the gas flow rate kept constant, the pressure drop across the test piece is measured using a water column graduated in conventional units called fasonaires. The fasonaire is thus expressed in millimeters of water column per 5 g (mass of the test piece).

[0032] The mineral wool panel also has a veil on each of its main faces. The veil intended to be turned towards the side from which the sound to be dampened comes, called the front veil, has a specific resistance to air flow less than or equal to 1 kPa.s / m, preferably less than or equal to 0.5 kPa.s / m, so as to allow as much sound as possible to pass towards the mineral wool, which will dampen the sound to allow good acoustic absorption. The opposite veil, called the rear veil, has a specific resistance to air flow greater than or equal to 1 kPa.s / m, preferably greater than or equal to 5 kPa.s / m, or even greater than or equal to 10 kPa.s / m: it is preferably airtight so as to provide good acoustic insulation. A waterproof veil has a specific resistance to air flow which is infinite, that is to say which is within the limits of what can be measured. The front veil can be painted to improve the aesthetics of the panel on the visible side.The front veil can be glued to the front face of the panel after light sanding to flatten it.

[0033] The mineral wool panel further comprises a binder mass rate of between 2% and 15% of the total mass, preferably between 2% and 10% of the total mass.

[0034] The mineral wool panel has a sound absorption α W greater than or equal to 0.9. The sound absorption is measured according to ISO 354. The α W indicator is then calculated according to ISO 11654. Throughout the application, the measurements were carried out with a plenum of 200 mm in construction height.

[0035] The mineral wool panel exhibits a sound insulation value (D nfw) of 38 dB or higher, preferably 39 dB or higher, or even 40 dB or higher, or 41 dB or higher, or even 42 dB or higher. The sound insulation is measured according to ISO 10848-1. The D nfw value is then calculated according to ISO 717-1. Throughout the application, measurements were taken with a plenum of 700 mm in construction height.

[0036] Sound absorption and insulation measurements are carried out on the panel with the front / rear sails.

[0037] The invention also relates to the method for manufacturing the mineral wool panel as described above. The method comprises a step of manufacturing a mat of mineral fibers, by internal centrifugation if they are glass fibers and by external centrifugation if they are rock fibers, then a step of creping the mat of glass fibers with a creping rate of between 1.5 and 5.

[0038] The manufacturing stage of the glass fiber mat by internal centrifugation is carried out using an installation comprising: ∘ at least one centrifuge capable of rotating around an X axis, in particular vertical, and whose peripheral band is pierced with a plurality of orifices to deliver filaments of a molten material, ∘ a high-temperature gaseous drawing means in the form of an annular burner which ensures the drawing of the filaments into fibers, and ∘ a receiving belt associated with suction means for receiving the fibers.

[0039] The centrifuge(s), also called fiberizing plates, in fact make it possible to form mineral fibers or other thermoplastic materials, by an internal centrifugation process associated with drawing by a high-temperature gas current. Internal centrifugation is particularly applicable to the industrial production of glass wool intended for use, for example, in the composition of thermal and / or acoustic insulation products. A stream of molten glass is introduced into each centrifuge rotating at high speed and pierced at its periphery by a very large number of orifices through which the glass is projected in the form of filaments under the effect of centrifugal force. These filaments are then subjected to the action of an annular drawing current at high temperature and speed along the wall of the centrifuge, a current which thins them and transforms them into fibers.The formed fibers are carried by this gaseous drawing current towards a receiving device generally consisting of a gas-permeable belt, called a receiving mat.

[0040] During the fiberglass mat manufacturing stage, a combination of parameters is set from among at least: • the viscosity of the molten glass, which is between 820 and 1500 poise, preferably between 950 and 1200 poise, • the burner pressure, which is between 200 and 1000 mm CE, preferably between 200 and 600 mm CE, • the total glass output per day per centrifuge, which is between 14 tonnes / day and 23 tonnes / day, preferably between 17 and 22 tonnes / day, • the number of holes in each centrifuge, which is between 5000 and 40000, preferably between 15000 and 35000, and • the rotation speed of the centrifuge at a speed greater than 2000 rpm.

[0041] These parameters allow in particular to adjust the surface density and the micronaire of the glass wool panel.

[0042] Preferably, the diameter of the orifices of each centrifuge is between 0.5 and 1.1 mm. Each centrifuge preferably has a diameter between 200 and 800 mm.

[0043] The manufacturing stage of the rock fiber mat by external centrifugation is carried out using an installation comprising ∘ at least three rotors capable of rotating around a Y axis, in particular horizontal, and whose contact with the molten material makes it possible to deliver fibers, and ∘ a receiving belt associated with suction means for receiving the fibers.

[0044] During the manufacturing stage of the rock fiber mat, a combination of parameters is set from at least: • the total rock removal per day, which is between 100 and 250 tonnes / day, • the rotation speed of the rotors, which is between 2000 and 4000 rpm.

[0045] These parameters allow in particular to adjust the surface density and the shape of the rock wool panel.

[0046] Preferably, each rotor has a diameter between 150 mm and 350 mm.

[0047] Furthermore, in both types of processes, binder is sprayed onto the mineral fibers before they fall onto the receiving belt, with a rate of between 2% and 15% of the total mass, preferably between 2% and 10% of the total mass. The mineral fiber mat is then placed in an oven, after creping, in order to polymerize the binder.

[0048] To finalize the product, a veil is glued to each of the main faces of the rock wool panel, the specificities of each of the veils having been given above.

[0049] A first example according to the invention is a glass wool panel with a density of 117 kg / m 3 and a thickness of 50 mm, having an air flow resistivity of 63 kPa.s / m 2 and a Young's modulus of 2.3 MPa. The micronaire is 4.3 / 5g. The creping rate is 3.5. The panel has a front veil with a specific air flow resistance of 0.3 kPa.s / m and a sealed rear veil. The panel is not cut in its thickness. The sound absorption α W is 0.9 and the sound insulation D nfw is 42 dB.

[0050] A second example according to the invention is a glass wool panel with a density of 102 kg / m 3 and a thickness of 52 mm, having an airflow resistivity of 68 kPa.s / m 2 and a Young's modulus of 0.9 MPa. The micronaire is 3.6 / 5g. The creping rate is 3.5. The panel has a front veil with a specific airflow resistance of 0.3 kPa.s / m and a sealed rear veil. The panel is not cut through its thickness. The sound absorption α W is 0.95 and the sound insulation D nfw is 41 dB.

[0051] A third example according to the invention is a rock wool panel with a density of 130 kg / m 3 and a thickness of 38 mm, having an air flow resistivity of 110 kPa.s / m 2 and a Young's modulus of 0.9 MPa. The fasonaire is 270. The creping rate is 3. The panel has a front veil with a specific air flow resistance of 0.3 kPa.s / m and a sealed rear veil. The panel is not cut in its thickness. The sound absorption α W is 0.9 and the sound insulation D nfw is 40 dB.

[0052] This made it possible to manufacture mineral wool panels with both good sound absorption and good sound insulation, without cutting into the thickness.

Claims

1. A mineral wool panel intended to be used as an acoustic panel and having: - a surface density of greater than or equal to 3.2 kg / m2, preferably greater than or equal to 4 kg / m2, or else greater than or equal to 4.5 kg / m2, or greater than or equal to 5 kg / m2, - an air flow resistivity of between 30 and 120 kPa.s / m2, preferably of between 50 and 110 kPa.s / m2, or of between 50 and 100 kPa.s / m2, or else of between 50 and 90 kPa.s / m2, or of between 50 and 80 kPa.s / m2, measured according to standard ISO 9053, - a Young's modulus of between 0.5 and 4 MPa, preferably of between 0.8 and 4 MPa, more preferably still of between 1.2 MPa and 4 MPa, or of between 1.5 MPa and 4 MPa, or else of between 2 MPa and 4 MPa, measured according to the method defined in the description, - a degree of crimping of between 1.5 and 5, - and the panel not being cut through the thickness along a plane substantially parallel to its main faces.

2. The panel as claimed in claim 1, additionally having a micronaire of between 2.5 / 5g and 6 / 5g, preferably between 3 / 5g and 6 / 5g, or between 3.5 / 5g and 6 / 5g, or else between 4 / 5g and 5 / 5g or a fasonaire of between 200 and 300, preferably between 200 and 290, or between 200 and 280, or else between 200 and 270.

3. The panel as claimed in claim 1 or 2, additionally comprising a veil on each of its main faces.

4. The panel as claimed in one of claims 1 to 3, wherein the veil intended to be facing the side from where the sound to be absorbed originates having a specific air flow resistance of less than or equal to 1 kPa.s / m, preferably less than or equal to 0.5 kPa.s / m, and the opposite veil having a specific air flow resistivity of greater than or equal to 1 kPa.s / m, preferably greater than or equal to 5 kPa.s / m, or even greater than or equal to 10 kPa.s / m, or else airtight.

5. The panel as claimed in one of claims 1 to 4, comprising a weight content of binder of between 2% and 15% of the total weight, preferably of between 2% and 10% of the total weight.

6. The panel as claimed in one of claims 1 to 5, having a sound absorption αW of greater than or equal to 0.9.

7. The panel as claimed in one of claims 1 to 6, having a sound insulation Dnfw of greater than or equal to 38 dB, preferably greater than or equal to 39 dB, or greater than or equal to 40 dB, or else greater than or equal to 41 dB, or greater than or equal to 42 dB.

8. A process for manufacturing the mineral wool panel as claimed in one of claims 1 to 7, comprising the following steps: - manufacturing a mat of mineral fibers by: ∘ internal centrifugation for glass fibers, using equipment comprising: ▪ at least one centrifuge capable of rotating about an axis X, in particular a vertical axis, and the peripheral band of which is pierced by a plurality of orifices for delivering filaments of a molten material, ▪ a high-temperature gas attenuating means in the form of an annular burner that attenuates the filaments into fibers, and ▪ a receiving belt associated with suction means for receiving the fibers, or ∘ external centrifugation for rock fibers, using equipment comprising: ▪ at least three rotors capable of rotating about an axis Y, in particular a horizontal axis, and the contact of which with the molten material makes it possible to deliver fibers, and ▪ a receiving belt associated with suction means for receiving the fibers, - crimping the mat of mineral fibers with a degree of crimping of between 1.5 and 5, preferably of between 2 and 5, or of between 2.5 and 5, or else of between 3 and 5.

9. The process as claimed in claim 8, wherein, during the step of manufacturing the mat of glass fibers, a combination of parameters is regulated from among at least: ∘ the viscosity of the molten glass, which is between 820 and 1500 poise, preferably between 950 and 1200 poise, ∘ the pressure of the burner, which is between 200 and 1000 mm WC, preferably between 200 and 600 mm WC, ∘ the total daily output of glass per centrifuge, which is between 14 metric tonnes / day and 23 metric tonnes / day, preferably between 17 and 22 metric tonnes / day, ∘ the number of holes of each centrifuge, which is between 5000 and 40 000, preferably between 15 000 and 35 000, and ∘ the rotational speed of the centrifuge at a speed greater than 2000 revolutions / minute.

10. The process as claimed in claim 8 or 9, wherein the diameter of the orifices of each centrifuge is between 0.5 and 1.1 mm.

11. The process as claimed in one of claims 8 to 10, wherein each centrifuge has a diameter of between 200 and 800 mm.

12. The process as claimed in claim 8, wherein, during the step of manufacturing the mat of rock fibers, a combination of parameters is regulated from among at least: ∘ the total daily output of rock, which is between 100 and 250 metric tonnes / day, ∘ the rotational speed of the rotors, which is between 2000 and 4000 revolutions / min.

13. The process as claimed in claim 12, wherein each rotor has a diameter of between 150 mm and 350 mm.

14. The process as claimed in one of claims 8 to 13, wherein binder is projected onto the mineral fibers before they fall onto the receiving belt, with a content of between 2% and 15% of the total weight, preferably of between 2% and 10% of the total weight, the mat of mineral fibers being passed into a drying oven, preferably after crimping, in order to polymerize the binder.

15. The process as claimed in one of claims 8 to 14, wherein a veil is adhesively bonded to each of the main faces of the mineral wool panel.