Plasterboard and its manufacture

Abstract

Plasterboard comprising a plaster core arranged between two covering sheets; wherein said plaster core comprises a matrix of gypsum crystals and air pores; wherein at least 90%, preferably at least 94%, more preferably at least 98% of the air pores are connected by a constriction; and wherein the average neighborhood coordination of said connected air pores is between 1.1 and 6, preferably between 3 and 5.

Description

Title of the invention: Plasterboard and its manufacture technical field

[0001] The invention relates to a plasterboard and its manufacturing process. Technical background

[0002] Plasterboard, for wall and ceiling systems, is a well-known application of plaster (gypsum), calcium sulfate dihydrate CaSO4.2(H2O). It consists of a plaster core sandwiched between two facing sheets, usually paper-based.

[0003] The basic material from which the gypsum crystal matrix of the plaster core is made is a calcium sulfate hemihydrate CaSO4 0.5(H2O), also called "stucco", which is produced by dehydration or calcination of gypsum CaSO4.2(H2O) to remove 1.5 water molecules.

[0004] Calcium sulfate hemihydrate exists in two forms: alpha calcium sulfate hemihydrate (a hemihydrate), produced from calcined gypsum in a water vapor-saturated atmosphere, and beta calcium sulfate hemihydrate (γ hemihydrate), produced under conditions of low partial pressure of water vapor. Both alpha and beta calcium sulfate hemihydrates can be used to manufacture plasterboard. Alpha calcium sulfate hemihydrate tends to produce a harder plasterboard with greater strength and density.

[0005] Porosity is introduced into the plaster matrix to reduce the weight of the plasterboard, to improve its sound absorption and resistance, and to reduce dust generation during mechanical processing, for example, cutting, screwing / nailing.

[0006] Porosity is often classified into water pores and air pores. Water pores are produced during the evaporation of excess water from the paste. Air pores are produced using a foaming agent and / or an aeration device. Water pores are generally irregularly shaped, complex, interwoven within the gypsum crystal matrix, and connected to each other to form a continuous network between the gypsum crystals. Air pores are generally spherical, separated from each other, and not connected to each other to form a continuous network. Water pores may be distributed within the walls of air pores.

[0007] In the plaster production process, significant quantities of water are consumed to form plaster pastes. Most of this water is removed by drying. A drying process is costly because it requires large amounts of energy to evaporate the water. It is also time-consuming because the migration of The water in the paste needs a certain amount of time to reach the surface.

[0008] Document WO 2008063295 A2 (UNITED STATES GYPSUM CO [US]) dated 29 / 05 / 2008 describes a plasterboard having a total porosity of about 80% to 92%, water pores with a size of less than 5 pm in diameter and air pores with a specific size distribution which reduces dust generation during mechanical processing, for example, cutting, screwing / nailing, of the plasterboard... The plasterboard is made with a plaster paste having a high water-to-stucco ratio (WSR [water-to-stucco ratio]), typically greater than 0.7.

[0009] Document WO 2009074875 A1 (LAFARGE PLÂTRES [FR]) dated 18 / 06 / 2009 describes a sound-absorbing and mechanically resistant plasterboard comprising a highly tortuous porous plaster core, thus a relatively low-porosity plaster core with low connectivity between the air pores. Reducing connectivity, i.e., reducing the percolation rate of the air pores, improves mechanical strength. The plasterboard is preferably made with a plaster paste having a water-to-plaster ratio (WSR) between 0.45 and 0.75.

[0010] Document WO 2022153181 Al [KNAUF GIPS KG [DE] dated 31 / 07 / 2022 describes a sound-absorbing panel comprising an open-cell gypsum core made of an interwoven gypsum matrix with air pores interconnected by open channels. The channels are distributed throughout the interwoven matrix and form complex, tortuous, labyrinth-like paths through the structure so that acoustic waves penetrate, travel through, and are absorbed. Summary of the invention Technical problem

[0011] Increasing the porosity of plasterboard is often desired to reduce its weight, improve its acoustic properties, and reduce dust generation during mechanical processing. However, a high level of porosity can quickly become detrimental to the mechanical strength of the board and may require a high water-to-plaster ratio (WSR), which, in turn, in addition to water consumption, also increases energy consumption during the subsequent drying stage.

[0012] Conversely, reducing porosity increases mechanical strength and decreases the water-to-stucco ratio (WSR), thus reducing water and energy consumption. However, all the advantages regarding sound absorption, lightness, and strength are lost.

[0013] Solution to the technical problem

[0014] According to a first aspect of the description, a plasterboard is proposed comprising a plaster core arranged between two cover sheets; in which said plaster core comprises a matrix of gypsum crystals and air pores; in which at least 90%, preferably at least 94%, more preferably at least 98% of the air pores are connected by a constriction; and in which the average neighborhood coordination of said connected air pores is between 1.1 and 6, preferably between 3 and 5.

[0015] Other advantageous embodiments are described below.

[0016] According to a second aspect of the description, a method is proposed for manufacturing a plasterboard according to the first aspect of the invention. Advantages of the invention

[0017] A significant advantage of the present description is that it provides a plasterboard with reduced weight and improved acoustic properties, while also reducing dust generation during mechanical processing and the water-to-stucco ratio (WSR) in its manufacture. This is achieved through a specific design of the air pore network in the gypsum matrix of the plaster core. Brief description of the drawings

[0018] [Fig-1] is a schematic diagram of a plasterboard.

[0019] [Fig.2] is a schematic diagram of an example of a plasterboard according to the first aspect of the invention.

[0020] [Fig.3] is a schematic representation of a detail II of the plasterboard of [Fig.2],

[0021] [Fig.4] is a graph representing the distribution of the air pore neighborhood coordination for examples of plasterboard according to the first aspect of the invention.

[0022] [Fig.5] is a graph representing the variation of the wall thicknesses of the connected air pores for examples of plasterboard according to the first aspect of the invention.

[0023] [Fig.6] is a graph representing the variation of wall thicknesses of unconnected air pores for examples of plasterboard according to the first aspect of the invention.

[0024] [Fig.7] is a graph of the cumulative volume distribution of the equivalent diameter of connected air pores for examples of plasterboard according to the first aspect of the invention.

[0025] [Fig.8] is a graph of the cumulative volume distribution of the equivalent diameter of unconnected air pores for examples of plasterboard according to the first aspect of the invention.

[0026] [Fig.9] is a graph representing the average neighborhood coordination of the pores of air as a function of the average diameter of the connected air pores for examples of plasterboard according to the first aspect of the invention.

[0027] [Fig. 10] is a graph representing the variation of the average neighborhood coordination of air pores as a function of porosity for examples of plasterboard according to the first aspect of the invention.

[0028] [Fig. 11] is a graph representing the variation of the average neighborhood coordination of air pores as a function of air permeability (Darcy's K) for examples of plasterboard according to the first aspect of the invention. Detailed description of implementation methods

[0029] With reference to [Fig. 1], a plasterboard 1000 comprises a plaster core 1001 sandwiched between two cover sheets 1002, 1003. The plaster core 1001 comprises a matrix of gypsum crystals 1004 mainly consisting of calcium sulfate hemihydrate CaSO4 0.5(H2O) and air pores 1005. The air pores 1005 are generally spherical in shape, separated from each other and not connected to each other to form a continuous network.

[0030] The plaster core 1001 may also include water pores (not shown). These are generally irregular and complex in shape within the gypsum crystal matrix 1004 so as to form a continuous network between the gypsum crystals.

[0031] In the first aspect of the invention, with reference to [Fig.2] and [Fig.3], a plasterboard 2000 is proposed comprising a plaster core 2001 arranged between two cover sheets 2002, 2003;

[0032] in which said plaster core 2001 comprises a matrix of gypsum crystals 2004 and air pores 2005;

[0033] wherein at least 90%, preferably at least 94%, more preferably at least 98% of the air pores 2005 are connected by a constriction 3001; and

[0034] wherein the average neighborhood coordination of said connected air pores 2005 is between 1.1 and 6, preferably between 3 and 5.

[0035] In the context of the invention, a "constriction" connecting air pores should be understood as it is currently defined in the technical field, that is, as an opening through the walls of two adjacent air pores so as to form between them a channel, a passage, or a window of communication. An illustrative example is provided in [Fig. 3].

[0036] In the context of the invention, a "neighborhood coordination" of a connected air pore is the number of adjacent neighboring air pores to which it is connected by a constriction. The average neighborhood coordination is the average of the neighborhood coordination measured or calculated for all connected air pores.

[0037] Neighborhood coordination can be measured by any suitable method, for example, image processing of MBE micrographs of cross-sections of plaster core samples and / or 3D X-ray tomography image processing of massive plaster core samples. X-ray tomography-based methods may be preferred as they can be more accurate than MBE micrograph-based methods, which require more data to be statistically representative of volume samples.

[0038] As mentioned previously, a plasterboard according to the first aspect of the invention can exhibit reduced weight, improved acoustic properties, while reducing dust generation during mechanical processing and the water-to-plaster ratio (WSR) for its manufacture. Without being bound by any theoretical explanation, it is assumed that an adjusted level of connectivity between the air pores of a plaster core makes it possible to improve sound insulation, reduce weight, and limit the amount of water used in its manufacture. This can be considered an advantageous compromise on porosity to simultaneously obtain the benefits of sound insulation, lightness, mechanical strength, and water savings.

[0039] In some embodiments, the maximum volume of connected pores is at least 60%, more preferably at least 75%.

[0040] In some embodiments, the specific mass of the gypsum crystal matrix may be at least 55%, preferably at least 65%, more preferably greater than 70% of the nominal specific mass of gypsum.

[0041] The specific mass of the gypsum crystal matrix can be measured by any suitable method or apparatus, for example, hydrostatic balances or gas pycnometers.

[0042] The nominal specific gravity of gypsum can depend on the amounts of the different gypsum phases and other compounds forming the crystals of the gypsum crystal matrix. For example, when the gypsum crystal is composed solely of calcium sulfate hemihydrate CaSO4 0.5(H2O), the nominal specific gravity of gypsum can be close to the specific gravity of calcium sulfate hemihydrate, i.e., 2.73 g / cm3. The specific gravity of the gypsum crystal matrix can then be at least 1.50 g / cm3, preferably 1.77 g / cm3, and more preferably greater than 1.91 g / cm3.

[0043] In some embodiments, the average equivalent diameter of the air pore constrictions may be less than 100 pm, preferably less than 80 pm, more preferably less than 60 pm.

[0044] In the context of the invention, the diameter of a constriction between air pores can be interpreted as the diameter of the largest tube that can be used to model this constriction. In practice, since the wall thickness between the air pores connected by a constriction can be relatively small, said constriction can be modeled as a circular hole, and the diameter of the constriction It could be the diameter of the largest circle that can be drawn to model this hole, or the diameter of a circle having the same area as the constriction.

[0045] Constrictions can be identified, and their diameter calculated, by image processing of 2D MBE micrographs and / or 3D X-ray tomography images. As with neighborhood coordination, methods based on X-ray tomography may be preferred because they can acquire 3D images that are more representative of volume samples.

[0046] Air pores connected by a constriction may have thinner walls than unconnected air pores due to their proximity. Because constrictions create channels within the porous structure and reduce the wall surface area of ​​the air pores, excessively thin walls can lead to greater susceptibility to external mechanical stresses from the plaster core. The porous structure can easily collapse, and the plaster can be easily crushed when external mechanical stresses, such as compressive stresses from screwing, are applied. Of course, the collapse of the porous structure can depend on the intensity of the applied mechanical stresses, and in some applications where low mechanical stresses are expected on the plasterboard, it may be unnecessary to avoid a more fragile porous structure.

[0047] Image processing of MBE micrographs of cross-sections of plaster core samples should be avoided to measure the wall thickness of air pores because many micrographs acquired on different cross-sections may be required for the measurement to be statistically representative of the actual wall thicknesses of the air pores in the volume sample.

[0048] Instead, the processing of 3D X-ray tomography images can be recommended. 3D images allow the reconstruction of the 3D distribution of air pores in a volume sample. By measuring the distance between the centers of two adjacent air pores and subtracting their respective radii, a distribution of wall thickness values ​​can be calculated.

[0049] In advantageous embodiments, the wall thicknesses of said connected air pores may further be between 2 µm and 20 µm, the average wall thickness of said connected pores being between 2 µm and 15 µm, preferably between 3 µm and 10 µm. The plasterboard comprising a plaster core with connected air pores having a wall thickness as described may exhibit higher mechanical strength.

[0050] Unconnected air pores can generally be further apart, and therefore can have thicker walls. Thicker walls can increase the overall specific mass of the plaster core. This can be prejudi- divisible for applications requiring a lighter plasterboard

[0051] Thus, in certain advantageous embodiments, the wall thicknesses of unconnected air pores can further be between 5 µm and 150 µm, the average wall thickness of said unconnected pores being between 25 µm and 75 µm, preferably between 30 µm and 60 µm. Unconnected air pores having such a wall thickness make it possible to reduce the weight of plasterboards without compromising mechanical strength.

[0052] Initially, large interconnected air pores, i.e., large-diameter air pores, can be considered valuable for reducing the weight of the plaster core, and thus decreasing its specific mass and reducing dust generation during mechanical processing. However, excessively large interconnected air pores can negatively impact the toughness of the plaster core and reduce its ability to withstand mechanical stresses. During mechanical processing, the plaster core may break unexpectedly.

[0053] In certain advantageous embodiments, the average diameter of connected air pores having a neighborhood connectivity between 2 and 6 can be less than 300 pm, preferably less than 250 pm, and more preferably less than 200 pm. These values ​​have been found to tend to provide lightweight, durable, and robust plasterboard.

[0054] Without being limited in any way to any specific range of specific masses for a plasterboard according to the invention, it has been found that a plasterboard can exhibit the best performance within an optimal range of specific masses. Thus, in certain advantageous embodiments, the specific mass of the plasterboard can advantageously be between 5 kg / m² and 15 kg / m², preferably between 5 kg / m² and 10 kg / m².

[0055] The total porosity, including air and water pores, directly affects the specific mass of the plaster core and, therefore, the specific mass of the plasterboard. Since air pores contribute most to the final specific mass of the plaster core, the total fraction of air pores, whether connected or unconnected, can be used as an approximation to characterize the lightness level of a plasterboard.

[0056] Thus, in certain advantageous embodiments, the average diameter of the connected and unconnected air pores can be less than 300 pm, preferably less than 250 pm, and more preferably less than 200 pm, for an overall porosity between 45% and 85%. Such a range of diameters for air pores can be useful for reducing the weight of the plaster core and the generation of dust during mechanical processing while maintaining a high level of lightness.

[0057] Air pores that are too small can hinder the achievement of average coordination of neighborhood of connected air pores 2005 between 2 and 6, preferably between 3 and 5. Preferably, in some embodiments, 85% of the porosity volume of the air pores may consist of air pores having a diameter greater than 100 pm, preferably greater than 150 pm.

[0058] The distribution of pore size, whether air pore or water pore, in the plaster core of a plasterboard according to the description can be unimodal or multimodal, for example, bimodal.

[0059] Thus, with regard to the distribution of the size of the air pores, in embodiments given by way of example, at least 50% by volume, preferably at least 75% by volume, of the air pores may have a diameter less than 150 pm, and at least 25% by volume, preferably 45% by volume, of the air pores may have a diameter greater than 100 pm.

[0060] Furthermore, regarding the distribution of the size of the water pores, in embodiments given by way of example, 50% to 90% of the water pores may have a diameter less than 3 pm and 5% to 30% of the water pores may have a diameter greater than 3 pm.

[0061] Air permeability measures the ability of a fluid, for example air, to flow through a material. It can be used to measure the airtightness of a building material and, since it is related to the open pore network, it can be used to characterize said open network. While the open pore network can include both connected air pores and water pores, the connected air pores generally contribute most to the overall porosity of the plasterboard, and the contribution of the water pores can be neglected. Air permeability can then be used as an approximation to characterize the open pore structure formed by the connected air pores. Methods based on Darcy's law are commonly used to measure the air permeability of gypsum cores or plasterboards.

[0062] In certain advantageous embodiments, the air permeability according to Darcy's law for a plaster according to the invention can be located between 10 10 and 10 13 m2, preferably between 10 10 and 10 12 m2.

[0063] In a second aspect of the description, a method for manufacturing a plasterboard is proposed according to any one of the embodiments of the first aspect of the invention, in which said method comprises the following steps:

[0064] - the formation of a plaster paste comprising at least 90%, preferably in less than 95% alpha gypsum hemihydrate; - mixing said plaster paste with a foaming agent and / or in a mixer-aerator; - the pouring of said plaster paste onto a first cover sheet; - the application of a second covering sheet on the said poured plaster paste; - the drying of the dough.

[0065] The process according to the second aspect of the invention can be adapted to manufacture a plasterboard according to any embodiment of the first aspect. In particular, the quantity of foaming agent and / or the aeration time by the mixer-aerator can be adjusted according to the required porosity and specific gravity.

[0066] As mentioned above, one of the outstanding advantages of a plasterboard according to the first aspect of the invention is that its manufacture requires a low water-to-stucco ratio. Thus, in preferred embodiments, in the process, the water-to-stucco ratio of the plaster paste can be less than 0.5, preferably less than 0.4. Examples

[0067] The features and advantages are now illustrated by means of the examples described below.

[0068] Four examples E1 to E4 of plasterboard according to the invention were manufactured according to the manufacturing recipes in Table 1 for their plaster pastes. The plaster pastes of examples E1 and E2 are composed of alpha hemihydrates (alpha HH) with a water-to-stucco ratio (WSR) of 31%, while those of examples E3 and E4 are prepared from beta hemihydrates (beta HH) with a WSR of 80%.

[0069] In addition, a retarder in the form of an aqueous solution of PlastRetard® from SICIT, diluted to 10% by weight (PlastRetard®), a dispersing agent in the form of sodium polynaphthalene sulfonate (PNS) and a heat-resistant setting accelerator (HRA) in the form of a mixture of ground plaster particles coated with a calcination inhibitor coating as described in US patent 3573947 A [UNITED STATES GYPSUM CO] of 06 / 04 / 1971 are added to the pastes in the proportions indicated in Table 1.

[0070] The foaming agent is an aqueous solution of Hyonic® PFM-10 diluted to 6% by weight and introduced into the pastes at 0.17 l / min with air introduced at different flow rates as described in Table 1.

[0071] {Table 1] Table 1 El E2 E3 E4 Type of HH Alpha Alpha Beta Beta HH (g) 2000 2000 2000 2000 Water (g) 612 612 1566 1566 HRA (g) 8 8 4 4 PlastRetard® (g) 8 8 30 30 PNS (g) 10 10 6 6 Air flow rate (l / min) 4 2 2 1 Foaming agent flow rate (l / min) 0.17 0.17 0.17 0.17 Paste WSR 31% 31% 80% 80%

[0072] Once prepared, the plasterboards of examples El and E4 were analyzed by X-ray tomography and various characteristics of the structure of the plaster core were extracted and measured by processing the 3D images acquired by X-ray tomography. In particular, the following characteristics were extracted: - the distribution, by occurrence, of the neighborhood coordination, N, of the air pores, [Fig.4]; - the distribution, by occurrence, oc, of the wall thicknesses, W (pm), of the connected air pores, [Fig.5]; - the distribution, by occurrence, oc, of the wall thicknesses, W (pm), of the unconnected air pores, [Fig.6]; - the cumulative volume distribution, cV, of equivalent diameter, d (pm) of connected air pores, [Fig.7]; - the cumulative volume distribution, cV, of equivalent diameter, d (pm) of unconnected air pores, [Fig.8].

[0073] In addition, the average neighborhood coordination, the average wall thickness of connected air pores, the average wall thickness of unconnected pores, the average equivalent diameter of constrictions, and the average diameter of connected air pores were also calculated. The results are given in Table 2.

[0074] The air permeability, Darcy's K, of each example was measured respectively by a method based on Darcy's law according to ISO 8841. The porosity was calculated from the measured weight of the plasterboards. The results are given in Table 2.

[0075] The mechanical resistance of each example was measured by mechanical indentation. An 8 mm spherical ball is driven into the board at a constant speed while measuring the slope of the resistance / displacement curve. The results are given in Table 2.

[0076] [Tables2] Table 2 E1 E2 E3 E4 Average neighborhood coordination 3.9 3.4 2.6 2.1 Porosity 75% 60% 46% 27% Specific gravity (kg / m3) 416 656 528 712 Air permeability, Dracy K (m2) 3.8 x 10-11 1.13 x 10-11 6.04 x 10-12 9.0 x 10-14 Average wall thickness of connected air pores (pm) 12.0 6.7 7.5 2.7 Average wall thickness of unconnected air pores (pm) 62.9 43.0 41.8 32.8 Average equivalent diameter of constrictions (pm) 90.8 57.8 49.2 28.6 Average diameter of connected air pores (pm) 258.8 136.9 114.4 68.6 Mechanical resistance (N / mm) 28.6 94.4 62.4 148.4

[0077] The average neighborhood coordination, N (avg) of the air pores as a function of the average diameter of the connected air pores for examples E1-E4 (solid circles).

[0078] The average neighborhood coordination, N (avg) of the air pores as a function of the porosity, p, for examples E1-E4 (solid circles).

[0079] The average neighborhood coordination, N (avg) of the air pores as a function of the density, d, for examples E1-E4 (solid circles).

[0080] Figure 4 shows that at least 90% of the air pores in the examples according to the invention have a neighborhood coordination between 0 and 8, with a maximum occurrence between 1 and 2. The average neighborhood coordination, as reported in Table 2, is between 2 and 6. It is higher for E1 and E2, which are made from of alpha hemihydrates, than for E3 and E4, which are in beta hemihydrates.

[0081] As illustrated in [Fig.10] and [Fig.11], for the same level of porosity or specific mass, the average neighborhood coordination of connected air pores is higher for examples than for non-examples.

[0082] As illustrated in [Fig.5], the maximum occurrence of the wall thickness of the connected air pores for the El - E4 examples is about 5 pm.

[0083] Regarding unconnected walls, examples are illustrated in [Fig. 6]. The distribution is narrower for examples up to 150 pm with a maximum occurrence centered around 25 pm.

[0084] The cumulative volume distribution of connected and unconnected air pore diameters is shown in [Fig.7] and [Fig.8] respectively. At least 75% of the connected air pores in the examples have a diameter less than 300 pm.

[0085] Approximately 90% of the unconnected air pores in the examples have a diameter of less than 100 pm.

[0086] All embodiments and examples including drawings, which are described here, whether they relate to the first or second aspect of the invention, can be combined by a person skilled in the art unless they appear technically incompatible.

[0087] Furthermore, although the invention has been described in connection with preferred embodiments, it should be understood that various modifications, additions and alterations can be made to the invention by a person skilled in the art without departing from the spirit and scope of the invention as defined in the claims.

Claims

Demands

1. Plasterboard comprising a plaster core disposed between two cover sheets; wherein said plaster core comprises a matrix of gypsum crystals and air pores; wherein at least 90%, preferably at least 94%, more preferably at least 98% of the air pores are connected by a constriction; and wherein the average neighborhood coordination of said connected air pores is between 2 and 6, preferably between 3 and 5.

2. Plasterboard according to claim 1, wherein the maximum volume of connected pores is at least 60%, more preferably at least 75%.

3. Plasterboard according to any one of claims 1 to 2, wherein the specific mass of the gypsum crystal matrix is ​​at least 55%, preferably at least 65%, more preferably greater than 70% of the nominal specific mass of plaster.

4. Plasterboard according to any one of claims 1 to 3, wherein the average equivalent diameter of the air pore constrictions is less than 100 pm, preferably less than 80 pm, more preferably less than 60 pm.

5. Plasterboard according to any one of claims 1 to 4, wherein the wall thicknesses of said connected air pores are between 2 pm and 20 pm, and wherein the average wall thickness of said connected pores is between 2 pm and 15 pm, preferably between 3 pm and 10 pm.

6. Plasterboard according to any one of claims 1 to 5, wherein the wall thicknesses of the unconnected air pores are between 5 pm and 150 pm, and wherein the average wall thickness of said unconnected pores is between 25 pm and 75 pm, preferably between 30 pm and 60 pm.

7. Plasterboard according to any one of claims 1 to 6, wherein the average diameter of connected air pores with a neighborhood connectivity between 2 and 6 is less than 300 pm, preferably less than 250 pm, more preferably less than 200 pm.

8. Plasterboard according to any one of claims 1 to 7, wherein the specific mass of the plasterboard is between 5 kg / m2 and 15 kg / m2, preferably between 5 kg / m2 and 10 kg / m2.

9. Plasterboard according to any one of claims 1 to 8, wherein the average diameter of connected and unconnected air pores is less than 300 pm, preferably less than 250 pm, more preferably less than 200 pm, for an overall porosity between 45% and 85%.

10. Plasterboard according to any one of claims 1 to 9, wherein 85% of the porosity volume consists of air pores having a diameter greater than 100 pm, preferably greater than 150 pm.

11. Plasterboard according to any one of claims 1 to 10, wherein at least 50% by volume, preferably at least 75% by volume, of the air pores have a diameter less than 150 pm, and wherein at least 25% by volume, preferably 45% by volume, of the air pores have a diameter greater than 100 pm.

12. Plasterboard according to any one of claims 1 to 11, wherein 50% to 90% of the water pores have a diameter less than 3 pm and wherein 5% to 30% of the water pores have a diameter greater than 3 pm.

13. Plasterboard according to any one of claims 1 to 12, wherein the air permeability according to Darcy's law is between 10 10 and 10 13 m2, preferably between 10 10 and 10 12 m2.

14. A method for manufacturing a plasterboard according to any one of claims 1 to 13, wherein said method comprises the following steps: - the formation of a plaster paste comprising at least 90%, preferably at least 95%, alpha gypsum hemihydrate; - the mixing of said plaster paste with a foaming agent in aqueous form; - the foaming of said mixture of said paste with said foaming agent in aqueous form; - the pouring of said plaster paste onto a first covering sheet; - the application of a second covering sheet onto said poured plaster paste; - the drying of the paste.

15. A method according to claim 14, wherein the water-to-stucco ratio of the plaster paste is less than 0.5, preferably less than 0.4.

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