Plasterboard and manufacture thereof

Abstract

Plasterboard comprising a plaster core disposed between two cover sheets; in which the 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 mean proximity coordination of the connected air pores is between 2 and 6, preferably between 3 and 5.

Description

Description Title: Plasterboard and its manufacture Technical field

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

[0002] Plasterboards, for wall and ceiling systems, are well-known applications of plaster (gypsum), calcium sulfate dihydrate CaSO4.2(H2O). They consist of a plaster core sandwiched between two cover sheets, usually paper-based.

[0003] The basic material from which the gypsum crystal matrix of the plaster core is made is calcium sulfate hemihydrate CaSC 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 comes in two forms: alpha calcium sulfate hemihydrate (a-hemihydrate), produced from calcined gypsum in a steam-saturated atmosphere, and beta calcium sulfate hemihydrate (hemihydrate [3], produced under conditions where the partial pressure of water vapor is low. Both alpha and beta calcium sulfate hemihydrates can be used to make gypsum board. Alpha calcium sulfate hemihydrate tends to provide a harder gypsum board 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 strength, and to reduce dust generation during mechanical processing, e.g., cutting, screwing / nailing.

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

[0007] In the plaster production process, significant amounts of water are consumed to form plaster pastes. Most of this water is removed by drying. A drying process is expensive because it requires large amounts of energy to evaporate the water. It is also time-consuming because it takes time for the water to migrate through the paste to reach the surface.

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

[0009] Document WO 2009074875 A1 (LAFARGE PLÂTRES [FR]) dated 18 / 06 / 2009 describes a soundproofing and mechanically strong plasterboard, comprising a porous plaster core of high tortuosity, therefore a relatively low-porosity plaster core with low connectivity between the air pores. Reducing the connectivity, i.e. reducing the percolation rate, of the air pores improves the mechanical strength. The plasterboard is preferably made with a plaster paste having a water-to-stucco ratio (WSR) between 0.45 and 0.75. WO 2022153181 A1 [KNAUF GIPS KG [DE] dated 31 / 07 / 2022 describes a sound-absorbing panel comprising an open-cell gypsum core consisting of an interlocking gypsum matrix with air pores interconnected by open channels. The channels are distributed throughout the interlocking matrix and form complex, tortuous, labyrinth-like paths through the structure for acoustic waves to penetrate, travel through and be absorbed. The process for obtaining the material constituting the board described in this application is a standard process in which a water-based foam is made from water and a foaming agent. This foam is then added and mixed with a slurry of the other ingredients of the initial formulation, this initial slurry being in particular obtained from a mixture of water and calcium sulfate hemihydrate. Such a process does not, however, make it possible to achieve a neighborhood coordination of at least 2 of the connected air pores in the final structure. Summary of the invention Technical problem

[0010] Increasing porosity in plasterboard is often sought 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-stucco ratio (WSR), which, in turn, in addition to water consumption, also increases energy consumption during the subsequent drying stage.

[0011] On the other hand, reducing porosity increases mechanical strength and reduces the water-to-stucco ratio (WSR), thereby reducing water and energy consumption. However, all the advantages of sound absorption, lightness, and strength are lost.

[0012] Solution to the technical problem

[0013] According to a first aspect of the disclosure, there is provided a 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 1, 1 and 6, preferably between 3 and 5.

[0014] Other advantageous embodiments are described below.

[0015] According to a second aspect of the description, there is provided a method for manufacturing a plasterboard according to the first aspect of the invention. Advantages of the invention

[0016] An outstanding advantage of the present disclosure is to provide a plasterboard having reduced weight, improved acoustic properties while reducing dust generation during mechanical processing and the water-to-stucco ratio (WSR) for its manufacture. This is achieved with a special design of the air pore network in the gypsum matrix of the plaster core. Brief description of the drawings

[0017] [Fig. 1] is a schematic diagram of a plasterboard.

[0018] [Fig. 2] is a schematic diagram of an example of a plasterboard according to the first aspect of the invention.

[0019] [Fig. 3] is a schematic representation of a detail II of the plasterboard of [Fig. 2],

[0020] [Fig. 4] is a graph showing the distribution of air pore neighborhood coordination for exemplary plasterboards according to the first aspect of the invention.

[0021] [Fig. 5] is a graph showing the variation in wall thicknesses of connected air pores for exemplary plasterboards according to the first aspect of the invention.

[0022] [Fig. 6] is a graph showing the variation of unconnected air pore wall thicknesses for exemplary plasterboards according to the first aspect of the invention.

[0023] [Fig. 7] is a graph of the cumulative volume distribution of the equivalent diameter of connected air pores for examples of plasterboards according to the first aspect of the invention.

[0024] [Fig. 8] is a graph of the cumulative volume distribution of the equivalent diameter of unconnected air pores for examples of plasterboards according to the first aspect of the invention.

[0025] [Fig. 9] is a graph showing the average neighborhood coordination of air pores as a function of the average diameter of connected air pores for exemplary plasterboards according to the first aspect of the invention.

[0026] [Fig. 10] is a graph showing the variation of the average neighborhood coordination of air pores as a function of porosity for examples of plasterboards according to the first aspect of the invention.

[0027] [Fig. 11] is a graph showing the variation of the average neighborhood coordination of the air pores as a function of the air permeability (Darcy's K) for examples of plasterboards according to the first aspect of the invention.

[0028] [Fig 12] is a scanning electron microscopy (SEM) photograph of the porous structure obtained according to Example 1 according to the invention. Detailed description of embodiments

[0029] Referring 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 consisting primarily of calcium sulfate hemihydrate CaSC 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 gypsum core 1001 may also include water pores (not shown). They are generally irregularly and complexly shaped in 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 provided comprising a plaster core 2001 disposed between two cover sheets 2002, 2003;

[0032] wherein 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 "choke" connecting air pores is to be understood as it is currently defined in the technical field, i.e. as an opening through the walls of two adjacent air pores so as to form a communication channel, pathway or window between them. 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 bulk plaster core samples. X-ray tomography-based methods may be preferred because they can be more accurate than MBE micrograph-based methods, which require more data to be statistically representative of volume samples.

[0038] As mentioned above, a plasterboard according to the first aspect of the invention can have reduced weight, improved acoustic properties while reducing dust generation during mechanical processing and the water-to-stucco 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 allows for improved acoustic insulation, reduced weight while limiting the amount of water to be used for manufacturing. This can be considered an advantageous compromise on porosity to obtain at the same time the benefits of acoustic insulation, lightness, mechanical strength and water savings.

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

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

[0041] The specific gravity 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 may depend on the amounts of the different gypsum phases and other crystal-forming compounds in the gypsum crystal matrix. For example, when the gypsum crystal is composed solely of calcium sulfate hemihydrate CaSC 0.5(H2O), the nominal specific gravity of the gypsum may be close to the specific gravity of calcium sulfate hemihydrate, i.e. 2.73 g / cm3. The specific gravity of the gypsum crystal matrix may then be at least 1.50 g / cm3, preferably 1.77 g / cm3, 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 being the diameter of the largest tube that can be used to model this constriction. In practice, since the thickness of the walls between the air pores that are connected by a constriction can be relatively small, said constriction can be modeled as a circular hole, and the diameter of the constriction can 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, X-ray tomography-based methods may be preferred because they can acquire 3D images that are more representative of volume samples.

[0046] Air pores connected to each other by a constriction may have thinner walls than unconnected air pores due to their proximity. Since constrictions create channels within the pore structure and reduce the wall area of ​​the air pores, excessively thin walls may result in greater sensitivity to external mechanical stresses from the plaster core. The porous structure may easily collapse, and the plaster may be easily crushed when external mechanical stresses, for example, compressive stresses due to screwing, are applied. Of course, the collapse of the porous structure may depend on the intensity of the applied mechanical stresses, and in some applications in which low mechanical stresses can be expected to be applied to the plasterboard, it may be unnecessary to avoid a weaker porous structure.

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

[0048] Instead, processing 3D X-ray tomography images can be recommended. 3D images allow the reconstruction of the 3D distribution of air pores in a sample volume. 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 pm and 20 pm, the average wall thickness of said connected pores being between 2 pm and 15 pm, preferably between 3 pm and 10 pm. 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 spaced further apart, and therefore may have thicker walls. Thicker walls can increase the overall specific gravity of the gypsum core. This can be detrimental for applications requiring lighter gypsum board.

[0051] Thus, in certain advantageous embodiments, the wall thicknesses of unconnected air pores may 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 the plasterboards without compromising the mechanical strength.

[0052] At first glance, large connected air pores, i.e. air pores with a large diameter, 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, pores Too large connected air gaps can negatively impact the toughness of the plaster core and reduce its ability to withstand mechanical stress. During mechanical processing, the plaster core may break unexpectedly.

[0053] In some advantageous embodiments, the average diameter of the connected air pores having a neighborhood connectivity between 2 and 6 may be less than 300 pm, preferably less than 250 pm, more preferably less than 200 pm. It has been found that these values ​​tend to provide lightweight, durable and robust plasterboards.

[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 / m 2 and 15 kg / m 2 , preferably between 5 kg / m 2 and 10 kg / m 2

[0055] Total porosity, including air and water pores, directly affects the specific gravity of the gypsum core and, therefore, the specific gravity of the gypsum board. Since air pores contribute the most to the final specific gravity of the gypsum core, the total fraction of air pores, whether connected or unconnected, can be used as an approximation to qualify the level of lightness of a gypsum board.

[0056] Thus, in certain advantageous embodiments, the average diameter of the connected and unconnected air pores may be less than 300 μm, preferably less than 250 μm, more preferably less than 200 μm, for an overall porosity between 45% and 85%. Such a range of diameters for air pores may 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] Too small air pores may hinder achieving an average neighborhood coordination of the 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 pore size distribution, whether air pore or water pore, in the plaster core of a plasterboard according to the description may be unimodal or multimodal, for example, bimodal.

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

[0060] Further, regarding the water pore size distribution, in exemplary embodiments, 50% to 90% of the water pores may have a diameter less than 3 μm and 5% to 30% of the water pores may have a diameter greater than 3 μm.

[0061] Air permeability measures the ability of a fluid, such as 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, can be used to characterize the open pore network. While the open pore network can include both connected air pores and water pores, the connected air pores generally contribute the 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 plaster cores or plasterboards.

[0062] In certain advantageous embodiments, the air permeability according to Darcy's law for a plaster according to the invention may be between 10' 10 and 10' 1 3 m2, preferably between 10' 10 and 10' 12 m2.

[0063] In a second aspect of the description, there is provided a method of manufacturing a plasterboard according to any one of the embodiments of the first aspect of the invention, wherein said method comprises the following steps: - the formation of a plaster paste comprising at least 90%, preferably at least 95% of alpha gypsum hemihydrate; - mixing said plaster paste with an aqueous solution of said foaming agent; - foaming the mixture of said paste with the aqueous solution of said foaming agent, in particular in a mixer-aerator; - pouring said plaster paste onto a first cover sheet; - the application of a second cover sheet on said poured plaster paste; - drying the dough.

[0064] The method according to the second aspect of the invention may be adapted to manufacture a plasterboard according to any embodiment of the first aspect. In particular, the amount of foaming agent and / or aeration time by the mixer-aerator may be adjusted according to the requirements to be achieved regarding porosity and specific mass.

[0065] As mentioned above, one of the exceptional advantages of a plasterboard according to the first aspect of the invention is that its manufacture requires a low WSR. Thus, in preferred embodiments, in the method, the water to stucco ratio of the plaster paste may be less than 0.5, preferably less than 0.4. Examples

[0066] The features and benefits are now illustrated by means of the examples described below.

[0067] Four examples E1 to E4 of plasterboards 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 (HH alpha) with a water to stucco ratio (WSR) of 31%, those of examples E3 and E4 are prepared from beta hemihydrates (HH beta) with a WSR of 80%.

[0068] 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 polynaphthalenesulfonate (PNS) and a heat-resistant setting accelerator (HRA) in the form of a mixture of ground gypsum particles coated with a calcination-inhibiting coating as described in US patent 3573947 A [UNITED STATES GYPSUM CO] dated 06 / 04 / 1971 are added to the pastes in the proportions indicated in Table 1.

[0069] 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 before foaming by introducing air into the mixture thus formed at different flow rates, as described in Table 1.

[0070] According to the present invention, the foaming agent in aqueous form is therefore previously mixed with the plaster pastes before foaming the mixture thus formed, said foaming allowing the formation of connected porosity.

[0071] {Table 1 ]

[0072] Once prepared, the plasterboards of examples E1 and E4 were analyzed by X-ray tomography and different characteristics of the plaster core structure 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 the 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, average wall thickness of connected air pores, average wall thickness of unconnected pores, average equivalent diameter of constrictions, and 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 strength 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] [Table 2]

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

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

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

[0080] Fig. 4 shows that at least 90% of the air pores of 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 alpha hemihydrates, than for E3 and E4, which are from 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 shown in Fig. 5, the maximum occurrence of the wall thickness of the connected air pores for examples E1 - E4 is about 5 pm.

[0083] For unconnected walls, examples are shown 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] About 90% of the unconnected air pores in the examples have a diameter less than 100 pm.

[0086] All embodiments and examples including drawings, which are described herein, whether relating to the first or second aspect of the invention, may be combined by those skilled in the art unless they appear technically incompatible.

[0087] If we now refer to Figure 12, this is a scanning electron microscopy SEM photograph of the porous structure obtained according to Example 1 according to the invention. The connections (constrictions) 2 between the air pores 1 of said structure are observed in black. Logically assuming that the SEM image allows half of the substantially spherical external volume of an air pore to be seen, it is possible to count the average neighborhood coordination rate of said air pores. The results are given in Table 3 below. We thus count an average neighborhood coordination of the order of 1.87 for a half-sphere, i.e. an overall coordination of 3.74, very close to the value of 3.9 obtained by X-ray tomography (see Table 2 above). The same analysis carried out on the SEM image of Figure 1 of publication WO2022 / 153181 shows that the average neighborhood coordination of the air pores of the structure obtained according to this prior art is of the order of 0.99.

[0088] [Table 3]

[0089] The results reported in Table 3 show that the teaching of publication WO2022 / 153181 leads to the production of a porous structure whose average coordination number of the air pores is of the order of 1, contrary to the object of the present invention.

[0090] Furthermore, although the invention has been described in connection with preferred embodiments, it should be understood that various modifications, additions, and alterations may be made to the invention by those skilled in the art without departing from the spirit and scope of the invention as defined in the claims.

Claims

Claims Plasterboard comprising a gypsum core disposed between two cover sheets; wherein said gypsum 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. A gypsum board according to claim 1, wherein the maximum volume of connected pores is at least 60%, more preferably at least 75%. A gypsum board according to any one of claims 1 to 2, wherein the specific gravity of the gypsum crystal matrix is ​​at least 55%, preferably at least 65%, more preferably greater than 70% of the nominal specific gravity of the gypsum.Plasterboard according to any one of claims 1 to 3, wherein the average equivalent diameter of the constrictions of the air pores is less than 100 pm, preferably less than 80 pm, more preferably less than 60 pm. 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. 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.Plasterboard according to any one of claims 1 to 6, wherein the average diameter of the 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 gravity of the plasterboard is between 5 kg / m 2 and 15 kg / m 2 , preferably between 5 kg / m 2 and 10 kg / m 2 .

9. Plasterboard according to any one of claims 1 to 8, wherein the average diameter of the 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 which is 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 of less than 150 pm, and wherein at least 25% by volume, preferably 45% by volume of the air pores have a diameter of 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 of less than 3 pm and wherein 5% to 30% of the water pores have a diameter of 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' 1 3 m 2, preferably between 10' 10 and 10' 12 m 2 14. Plasterboard according to any one of claims 1 to 13 wherein the average neighborhood coordination of said connected air pores is between 3 and 6, preferably between 3 and 5.

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

16. The method of claim 15, wherein the water to stucco ratio of the plaster paste is less than 0.5, preferably less than 0.4.

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