Methods for improving the airtightness of buildings using biopolymer-based membranes

Abstract

The present invention relates to a method for improving the airtightness of a building or a room in a building, comprising the use of a vapor barrier membrane on the inner surface of a wall of said building or said room in said building, characterized in that said vapor barrier membrane is a humidity regulating membrane having an active portion, The active moiety is an intermediate layer having a thickness between 2 μm and 200 μm, preferably between 4 μm and 100 μm, and made of a biopolymer having a water vapor permeability coefficient P1, which increases with the average relative humidity and is at least 300 Barrer, measured at 23° C. and an average relative humidity of 25.5%; and on both sides of, preferably in contact with, the intermediate layer; - two outer layers having a thickness of 100 nm to 20 μm, preferably 200 nm to 2.5 μm, each consisting independently of the other of an organic polymer having a water vapor permeability coefficient P2 of at most 250 Barrer, preferably 0.05 to 100 Barrer, in particular 1.0 to 20 Barrer, measured at 23° C. and an average relative humidity of 25.5%; The present invention relates to a method comprising the steps of:

Description

[Technical Field]

[0001] The present invention relates to a method for improving the airtightness of a building or room in a building using a vapor barrier membrane, the vapor barrier membrane having a hydrophilic middle layer based on a biopolymer and two outer layers that are relatively more hydrophobic than the middle layer. [Background technology]

[0002] Humidity regulating vapor membranes have been known for many years, whose water vapor transmission rate varies with the humidity of the air. For reasons explained, for example, in WO 96 / 33321, there is a need to have a membrane that allows water vapor to pass easily at high relative humidity (RH) (70%-100% RH) and effectively blocks it at low relative humidity (below 50% RH).

[0003] When placed on the inner surface of the insulation (the surface facing the interior of a building or room), such membranes prevent water vapor from penetrating the space between the membrane and the wall from the inside of the building and condensing on the wall during cold, dry seasons (cold wall). Conversely, during hot seasons, the membrane's high permeability allows moisture potentially present in the structural elements of the frame to escape toward the inside of the building. This property is particularly important not only in new buildings (where certain elements may have a very high moisture content during installation due to storage conditions), but also in the event of water infiltration into existing structures. In both cases, it is important in summer to be able to dry the entire structure effectively, both toward the outside and the inside of the building. This need is particularly critical when the elements that make up the system support the growth of microorganisms.

[0004] Such vapor barrier membranes behave differently depending on the relative humidity conditions around them and are often referred to as "smart vapor retarder" (SVR) membranes. In this application, the adjectives "humidity regulating" and "smart" are used synonymously when describing the change in water vapor permeability of a vapor barrier membrane.

[0005] The water vapor transmission rate of the membrane is calculated as the "equivalent air layer thickness" (S d ) This thickness is expressed in meters and corresponds to the thickness of the air layer that would oppose the equivalent resistance to the diffusion of water vapor. Thus, the greater the equivalent air layer thickness, the less permeable the membrane is to water vapor. The equivalent air layer thickness (S d ) may be determined in accordance with standards EN 1931 and EN ISO 12572.

[0006] Humidity control vapor membranes are generally considered to be even more beneficial and effective because their equivalent air thickness is higher at low relative humidity and lower at high relative humidity.

[0007] Organic vapor barrier membranes are commercially available and described in the state of the art and are generally based on synthetic organic polymers made from petroleum monomers.

[0008] The most frequently mentioned and used polymers are polyamides, especially polycaprolactam, polyvinyl alcohol (PVOH), copolymers of ethylene and vinyl acetate and / or vinyl alcohol (EVA and EVOH). Most hydrophilic polymers (PVOH, EVOH) may be combined in multilayer structures with thin, more hydrophobic layers, especially those based on polyolefins, such as polyethylene, polypropylene, and copolymers of ethylene and propylene.

[0009] Examples of literature describing such "smart" vapor barrier membranes are WO 2007 / 010388, WO 2006 / 034381, WO 2005 / 110892, U.S. Pat. No. 7,008,890, U.S. Pat. No. 6,808,772 and U.S. Pat. No. 6,878,455.

[0010] The aim of the research that led to the present invention was to replace prior art humidity-regulating vapor barrier membranes based on petroleum-derived polymers (which are generally non-biodegradable) with humidity-regulating vapor membranes based on bio-derived and / or biodegradable polymers. These bio-derived and / or biodegradable polymers will hereinafter be referred to as "biopolymers." The biopolymers are preferably bio-derived, i.e., based on short-term renewable biological sources. In particularly preferred embodiments, the biopolymers used in the present membranes are both bio-derived and biodegradable.

[0011] Biopolymers derived from living organisms include natural organic polymers present in biomass, organic polymers obtained by physically and / or chemically modifying these natural polymers, and synthetic organic polymers obtained by polymerization of biologically derived components.

[0012] Such biopolymer-based membranes, such as membranes based on cellulose, chitosan, or poly(3-hydroxybutyrate) (PHB), are known and have been used as alternatives to films based on petroleum-derived synthetic polymers, particularly in the field of food packaging. In this field, membranes generally require water vapor permeability that is relatively independent of humidity and temperature conditions. Furthermore, in the field of food packaging, the service life of packaging films is quite limited, typically ranging from a few days to a few weeks, or at most a few months. In contrast, in the field of vapor barrier membranes, a long service life of at least several years or even decades is required.

[0013] Membranes based on biopolymers are often hydrophilic to some extent, making them highly permeable to water vapor. The equivalent air layer thickness of these membranes is generally less than 1 m, and its absolute value varies little with the relative humidity of the atmosphere surrounding them. Therefore, these membranes maintain an extremely high permeability to water vapor, regardless of the ambient conditions.

[0014] Without wishing to be bound by any theory, it is believed that the low variation in water vapor transmission rate of these somewhat hydrophilic membranes can be attributed to the plasticizing effect of water "dissolving" in the membrane, even at low humidity: the higher the ambient humidity, the more the membrane material is plasticized by water, making it easier for water molecules to diffuse within the membrane.

[0015] Therefore, the main drawback of these membranes made of biopolymers, for their possible use as humidity-controlling vapor barriers, lies in the fact that they cannot function satisfactorily during cold, dry seasons because their permeability to water vapor remains generally too high at low relative humidities for them. Thus, a membrane made solely of cellulose would not be able to form a sufficient barrier against water vapor penetrating from inside the building and would not be able to prevent water vapor from penetrating the space between the membrane and the wall and condensing in the insulation and on the inner surface of the exterior wall. Summary of the Invention [Problem to be solved by the invention]

[0016] In summary, biopolymer-based hydrophilic membranes used in the food packaging sector remain too permeable to water vapor under conditions of low relative humidity (cold season). They are therefore not "smart" enough to function adequately as vapor barriers in the field of building insulation (thermal insulation), in particular for increasing airtightness and improving the management of water vapor flow within buildings. [Means for solving the problem]

[0017] The present invention is based on the surprising discovery that it is possible to very significantly improve the "smartness" of biopolymer-based membranes, thus making them suitable for use as vapor barrier membranes in the construction sector, by applying a very thin layer of a hydrophobic polymer, which is not very permeable to water vapor, to each of the two faces of the biopolymer-based membrane.

[0018] This finding was even more surprising considering that hydrophobic polymers deposited on both sides of biopolymer membranes have water vapor permeability that is independent of the ambient relative humidity. In other words, a membrane consisting solely of these hydrophobic polymers would have no humidity-regulating properties. Therefore, it would not have been possible to provide a significant improvement in the "smartness" of membranes made of one or more hydrophilic biopolymers by depositing these same hydrophobic polymers on their sides, allowing them to have extremely low water vapor permeability in dry periods and high water vapor permeability in wet periods. DETAILED DESCRIPTION OF THE INVENTION

[0019] The object of the present invention is therefore a method for improving the airtightness of a building or a room in a building, comprising the use of a vapor barrier membrane on the inner surface of a wall of the building or a room in a building, characterized in that the vapor barrier membrane is a humidity control membrane having an active portion, The active part is: an intermediate layer having a thickness of 2 μm to 200 μm, preferably 4 μm to 100 μm, in particular 5 to 50 μm, and made of a biopolymer having a water vapor permeability coefficient P1 which increases with the average relative humidity and is at least 300 Barrer when measured at 23° C. and an average relative humidity of 25.5%; and on either side of, and preferably in contact with, the intermediate layer; two outer layers having a thickness of 100 nm to 20 μm, preferably 200 nm to 2.5 μm, and each consisting independently of the other of an organic polymer having a water vapor permeability coefficient P2 of at most 250 Barrer, preferably 0.05 to 100 Barrer, in particular 1.0 to 20 Barrer, measured at 23° C. and an average relative humidity of 25.5%; Includes:

[0020] The active part of the membrane is preferably a three-layer structure made up of a middle layer and two outer layers, as defined above.

[0021] The middle layer and the two outer layers are, of course, continuous layers that are not perforated, and therefore they are impermeable to fluids, whether liquids or gases.

[0022] The permeability coefficients P1 and P2 are those of the polymers forming the middle and outer layers, respectively. They correspond to the ratio of the mass flow rate (Q) of water vapor passing through an area (A) of a membrane of the tested polymer having a given thickness (E) under the influence of a water vapor pressure difference (dP) existing on both sides of the membrane.

[0023] [Number 1] P = (Q × E) / (A × dP)

[0024] They are determined according to the experimental protocol detailed below and are expressed in "Barrer", i.e., mass flow rate Q in cm per second. 3 (pressure and temperature), the thickness E is expressed in cm, and the area A of the traversed region is expressed in cm 2 and the water vapor pressure difference (dP) is expressed in cmHg (see, in particular, SAStern, Journal of Polymer Science Part A-2, vol. 6 (1968), pages 1933-1934).

[0025] Thus, the membrane of the present invention comprises a relatively thick layer (middle layer) based on a hydrophilic biopolymer, which is coated on both sides with a continuous layer (outer layer) of a hydrophobic polymer.

[0026] The two outer layers generally have a thickness smaller than that of the intermediate layer, the ratio of the thickness of the intermediate layer to the thickness of each outer layer being advantageously between 1.5 / 1 and 1000 / 1, preferably between 2 / 1 and 500 / 1, in particular between 3 / 1 and 200 / 1.

[0027] The two outer layers are preferably in direct contact with the middle layer, ie, the interface between the layers is preferably free of adhesive.

[0028] In a less preferred embodiment, the outer layer is adhered to the middle layer by an adhesive, which will preferably have a permeability coefficient P3 greater than the permeability coefficients P1 and P2. In other words, the adhesive should not offer a resistance to the diffusion of water vapor greater than the resistance from each layer that makes up the membrane.

[0029] The layers defined above form the "active part" of the membrane of the invention, which part is preferably a membrane obtained in a known manner by coextrusion of the thermoplastic polymers forming the different layers, by thermal bonding of a film (outer layer) onto an intermediate layer, or by depositing a coating on both sides of the intermediate layer.

[0030] The active part has, in principle, a mechanical strength that allows it to be used alone, i.e., without a support layer, but particularly for active layers of small thickness (less than 50 μm), it may be advantageous to reinforce it with an air-permeable mechanical structure whose resistance to the diffusion of water vapor is therefore negligible compared to the resistance of the air-impermeable active layer.

[0031] Therefore, in an advantageous embodiment, the vapor barrier membrane further comprises an air-permeable reinforcing or protective layer in direct contact with the active portion, i.e., one of the outer layers. This support layer may be an air-permeable grid, perforated plate, perforated foam, or woven or nonwoven fabric. It is preferably an air-permeable fabric, preferably a nonwoven fabric. Particularly preferred examples of support layers include nonwoven fabrics made of polypropylene or polyester fibers or glass fibers. The support layer(s) are preferably attached to the active membrane or active layer by bonding with a polyurethane adhesive. The present invention also encompasses membranes in which a reinforcing structure, such as a grid or nonwoven fabric, is incorporated into the active portion of the membrane, especially in the intermediate layer.

[0032] The water vapor permeability coefficient P2 of the organic polymer that makes up the outer layer does not change significantly with the average relative humidity. 2wet / P 2dry is generally 1.0 to 1.10, preferably 1.0 to 1.05.

[0033] As explained at the beginning, the biopolymers forming the intermediate layer are organic polymers of biological origin and / or biodegradable origin. They are preferably of biological origin.

[0034] The biologically derived biopolymer is preferably selected from the group consisting of: -Osides, -protein, and -Synthetic polymers obtained from biologically derived monomers.

[0035] Osides include heterosides, whose hydrolysis produces non-sugar compounds, and holosides, which are polymers of only sugars.

[0036] Examples of osides that may be used to form the intermediate layer of the vapor barrier of the present invention include those selected from the group consisting of alginate, carrageenan, cellulose, especially regenerated cellulose (cellulose hydrate), chitin, chitosan, pectin, dextrin, starch, curdlan, FucoPol, gellan gum, pullulan and xanthan.

[0037] The protein is advantageously selected from the group consisting of gluten, soy protein isolate, zein, whey protein, casein, collagen and gelatin.

[0038] Most of these biopolymers extracted from biomass have a high affinity for water and dissolve or swell in water to form hydrogels.

[0039] As a result, it may be advantageous or necessary to chemically modify them to reduce their hydrophilicity, and in particular to crosslink them to make them insoluble in water.

[0040] Examples of chemically modified biologically derived biopolymers include cellulose esters, especially cellulose acetate, cellulose ethers (especially ethyl cellulose, hydroxyethyl cellulose), nitrocellulose, starch esters and ethers.

[0041] A third category of biologically derived biopolymers is formed by polymers synthesized from biologically derived monomers.

[0042] These polymers may be linear or branched and therefore thermoplastic or thermoset.

[0043] Examples of synthetic polymers obtained from monomers of biological origin may include those selected from the group consisting of: Polyhydroxyalkanoates (PHAs), in particular polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), polylactic acid (PLA), polyglycolic acid (PGA), poly(lactide-co-glycolide) (PLGA), polymers obtained by polymerization of lipid monomers, and thermosetting polymers obtained by reaction of monosaccharides, disaccharides, oligosaccharides and / or alditols with polycarboxylic acids and / or polyaldehydes.

[0044] Thermosetting polymers obtainable by reaction of mono-, di-, oligosaccharides and / or alditols with polycarboxylic acids and / or polyaldehydes are well known in the field of mineral wool binders and are described in detail, for example, in WO 2009 / 080938, WO 2010 / 029266, WO 2013 / 014399, WO 2013 / 021112 and WO 2015 / 132518 in the name of the Applicant.

[0045] As explained at the beginning, polymers of petrochemical origin may also be used to form the intermediate layer of the membrane of the invention, provided that they are biodegradable within the meaning of the NF EN 13432 standard.

[0046] The biodegradable biopolymer may advantageously be selected from the group consisting of homopolymers such as poly(caprolactone) (PCL) and poly(butylene succinate) (PBS), aliphatic copolyesters such as poly(butylene succinate-co-adipate), aromatic copolyesters such as poly(butylene adipate-co-terephthalate) (PBAT) and polyesteramides.

[0047] All biopolymers constituting the intermediate layer have a permeability coefficient P1 measured under dry conditions (average relative humidity of about 25%) at 23°C of 300 Barrer or more, preferably 300 to 50,000 Barrer, in particular 400 to 30,000 Barrer, and ideally 500 to 20,000 Barrer.

[0048] This transmission coefficient is determined as follows:

[0049] Five samples of the same membrane thickness (E) are sealed with a sealing product onto a test cup containing a desiccant (CaCl2 powder, which provides a relative humidity of approximately 1% in the test cup). A template is placed on the surface of the film before applying the sealing product to form an exchange zone of a defined zone (A) free of the sealing product. Various sealing products may be used. The sealing product is, for example, a mixture of 60% microcrystalline wax and 40% refined crystalline paraffin.

[0050] The cups thus produced are placed in a temperature-controlled test chamber (also called a climate chamber) at a temperature (23°C) and relative humidity (50%).

[0051] The difference in water vapor partial pressure (dP) between the inside of the test cup and the chamber causes the vapor to migrate through the exchange zone of the membrane. Periodic weighing of the cup is carried out to determine the steady-state water vapor transmission rate (Q) and, by calculation, the water vapor permeability coefficient of the considered film, expressed in Barrer. The average of the measured permeabilities for the different assemblies is then calculated, corresponding to the aforementioned permeability coefficient P1.

[0052] The hydrophilic intermediate layer of the vapor barrier membrane of the present invention is covered on both sides with continuous layers of organic polymers that are more hydrophobic and have lower water vapor permeability than the intermediate layer. The term "continuous" here means that each outer layer completely covers one side of the central membrane, preventing it from coming into contact with the ambient atmosphere. The two continuous layers may be of the same chemical nature and thickness, or may be of different chemical natures and / or different thicknesses. Each layer is in direct contact with the intermediate layer.

[0053] The permeability coefficient P2 of each outer layer is equal to a maximum of 250 Barrer, preferably between 0.05 and 100 Barrer, in particular between 1.0 and 20 Barrer. The permeability coefficient is determined in the same way as the coefficient P1.

[0054] The organic polymer constituting the outer layer is advantageously selected from the group consisting of polypropylene, polyethylene, poly(ethylene-co-propylene), homopolymers and copolymers of vinyl monomers selected from vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene and acrylonitrile.

[0055] A vapor barrier membrane having an intermediate layer made of cellulose, in particular regenerated cellulose, and two outer layers formed of polyethylene, polypropylene, ethylene-propylene or poly(vinylidene chloride) copolymer, preferably poly(vinylidene chloride), is a particularly preferred embodiment of the vapor barrier membrane to be used in the method of the present invention.

[0056] The active part of the vapor barrier membrane used in the method of the invention advantageously has a thickness of 5.0 μm to 240 μm, preferably 10 μm to 120 μm, in particular 15 μm to 80 μm. These values ​​correspond to the active part of the membrane (3 layers), but do not include possible reinforcing and / or protective structures.

[0057] Preferably, the wall of the room or barrier or building whose airtightness is to be improved is insulated, i.e., covered, with insulation (thermal insulation), and the vapor barrier membrane is attached to or incorporated within the insulation. In one embodiment of a method for improving the airtightness of a building or a room in a building, the vapor barrier membrane of the present invention is then attached to a position internal to the insulation, preferably in direct contact therewith. This attachment may be by any suitable means that does not significantly reduce the airtightness of the membrane. For example, it may be by adhesive, stapling, or a mechanical fastening system, which may use hook and loop fasteners (Velcro®-type hook-and-loop fasteners).

[0058] In another embodiment of the method of the present invention, the vapor barrier membrane is integrated into the insulation and attached to the wall of the room or building simultaneously with the insulation, in which case the membrane is oriented parallel to the two major surfaces of the insulation, and preferably positioned closer to the major surface facing the interior of the room or building than to the major surface facing the wall.

[0059] The insulation material may be any water vapor permeable barrier material, including, inter alia, foams and fiber-based materials. It is preferably made of mineral fibers (mineral wool) or natural organic fibers (lignocellulosic fibers, cellulose cotton, animal wool), synthetic fibers (polyester fibers) or man-made fibers. It is preferably made of mineral wool. [Example]

[0060] Five water vapor barrier membranes were subjected to evaluation of water vapor permeability under wet and dry conditions.

[0061] To this end, each membrane is placed to close an aluminum cup using molten paraffin wax (a mixture of 60% microcrystalline wax and 40% refined crystalline paraffin) as a binding product, thereby ensuring a tight seal. To measure water vapor transmission rates in dry conditions, calcium chloride is introduced into the tower before sealing it with the membrane, resulting in an internal relative humidity of approximately 1%. The cup / membrane assembly is then introduced into a climate chamber set to a relative humidity of 50% and a temperature of 23°C, generating a water vapor differential pressure (dP) across the membrane. The flow rate (Q) of water vapor through zone (A) of the membrane with thickness (E) is determined by weighing the cup over time, and the permeability coefficient (expressed in Barrers) is calculated using the following formula:

[0062] [Number 2] P = (Q × E) / (A × dP)

[0063] The permeability coefficient P1 calculated in this way corresponds to an average relative humidity of 25.5% ((1% + 50%) / 2).

[0064] When measuring water vapor transmission rate under humid conditions (average relative humidity 90%), the procedure is similar except that liquid water is introduced into the cup to set the relative humidity to 100% and the relative humidity in the climate chamber is set to 80%.

[0065] Additionally, the equivalent air layer thickness (Sd) is determined for each membrane according to EN ISO12572.

[0066] The first membrane is a vapor barrier membrane according to the present invention. It consists of a 17.5 μm thick cellulose intermediate layer sandwiched between two layers of polyvinylidene chloride (PVDC), each 750 nm thick. The moisture permeability coefficient P1 of the cellulose intermediate layer is 5600 Barrer at 25.5% relative humidity (23°C) and 34600 Barrer at 90% relative humidity (23°C); the moisture permeability coefficient P2 of the PVDC layer is 5 Barrer at 23°C. This does not change with relative humidity.

[0067] The second and third membranes consist of cellulose only and have the same permeability coefficient P1 as the middle layer of the first membrane.

[0068] The fourth membrane is made of a single active layer of polyamide 6 with a thickness of 40 μm attached to a polypropylene nonwoven fabric, and is commercially available under the name Vario KM Duplex™ (Saint-Gobain Isover).

[0069] The fifth membrane is a three-layer membrane according to the prior art, with the active part consisting of a middle layer of ethylene vinyl alcohol copolymer (EVOH) sandwiched between two layers of polyamide 6 attached to a polypropylene nonwoven fabric. This membrane is commercially available under the name Vario Xtra™ (Saint-Gobain Isover).

[0070] The technical properties of the membrane (layer composition, thickness, equivalent air layer thickness under dry and humid conditions) are summarized in Table 1 below.

[0071] [Table 1]

[0072] It can be seen that the difference in equivalent air layer thickness under dry and wet conditions for the three-layer vapor barrier membrane according to the present invention (Membrane 1) is significantly stronger than that for all comparative membranes (Membranes 2 to 5).

[0073] Two cellulose membranes (Membranes 2 and 3) have an equivalent air layer thickness (S) of less than 1 m in either wet or dry conditions. d ) due to their insufficient humidity control power, they are not suitable as vapor barrier membranes. During dry and cold seasons, such membranes would allow excessive amounts of water to pass into the space between the membrane and the building wall. This insufficiently "smart" behavior is significantly improved by the presence of two thin PVDC layers.

[0074] It should also be noted that the membrane according to the invention (Membrane 1) has a total thickness (19 μm) that is much lower than the thickness of the active part of the two membranes sold by the Applicant, which are equal to 40 μm (VScenario KM Duplex™) and 30 μm (VScenario Xtra™), respectively. The superior performance of the membrane according to the invention allows for a reduction in raw materials and therefore costs. The present disclosure includes the following aspects. <Aspect 1> A method for improving the airtightness of a building or a room in a building, comprising using a vapor barrier membrane on an inner surface of a wall of the building or the room in the building, wherein the vapor barrier membrane is a humidity control membrane having an active portion; The active moiety is an intermediate layer having a thickness of 2 μm to 200 μm, preferably 4 μm to 100 μm, and a water vapor permeability coefficient P 1 The biopolymer has a water vapor permeability coefficient P 1 increases with average relative humidity and is at least 300 Barrer when measured at 23°C and an average relative humidity of 25.5%; and on both sides of, preferably in contact with, the intermediate layer; two outer layers, each having a thickness of 100 nm to 20 μm, preferably 200 nm to 2.5 μm, and each having, independently of one another, a water vapor permeability coefficient P 2 and the organic polymer has a water vapor permeability coefficient P 2 The temperature of the two outer layers is at most 250 Barrer, preferably 0.05 to 100 Barrer, and particularly 1.0 to 20 Barrer, when measured at 23°C and an average relative humidity of 25.5%. Including, method. <Aspect 2> The water vapor permeability coefficient P of the organic polymer constituting the outer layer 2 does not vary significantly with the average relative humidity. <Aspect 3> 3. The method of claim 1 or 2, wherein the biopolymer forming the intermediate layer is a biopolymer of biological origin selected from the group consisting of oxides, proteins, and synthetic polymers obtained from monomers of biological origin. <Aspect 4> 4. The method according to aspect 3, characterized in that the oside is selected from the group consisting of alginic acid, carrageenan, cellulose, in particular regenerated cellulose, chitin, chitosan, pectin, dextrin, starch, curdlan, FucoPol, gellan gum, pullulan and xanthan. <Aspect 5> 4. The method of claim 3, wherein the protein is selected from the group consisting of gluten, soy protein isolate, zein, whey protein, casein, collagen, and gelatin. <Aspect 6> 6. The method according to aspect 4 or 5, wherein the oxides and proteins are chemically modified. <Aspect 7> 4. The method according to aspect 3, characterized in that the synthetic polymer obtained from monomers of biological origin is selected from the group consisting of polyhydroxyalkanoates (PHAs), polylactic acids (PLAs), polyglycolic acids (PGAs), poly(lactide-co-glycolides) (PLGAs), polymers obtained by polymerization of lipid monomers, thermosetting polymers obtained by reaction of monosaccharides, disaccharides, oligosaccharides and / or alditols with polycarboxylic acids and / or polyaldehydes. <Aspect 8> 3. The method of any one of aspects 1 to 2, wherein the biopolymer is a biodegradable polymer selected from the group consisting of aliphatic polyesters, aliphatic copolyesters, aromatic copolyesters, and polyesteramides. <Aspect 9> 9. The method of claim 8, wherein the biodegradable biopolymer is selected from the group consisting of poly(caprolactone) (PCL), poly(butylene succinate) (PBS), poly(butylene succinate-co-adipate), and poly(butylene adipate-co-terephthalate) (PBAT). <Aspect 10> 10. The method of any one of aspects 1 to 9, wherein the organic polymer comprising the outer layer is selected from the group consisting of polypropylene, polyethylene, poly(ethylene-co-propylene), homopolymers and copolymers of vinyl monomers, wherein the vinyl monomers are selected from vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, and acrylonitrile. <Aspect 11> 2. The method of claim 1, wherein the middle layer is made of cellulose and the two outer layers are made of polyethylene, polypropylene, ethylene-propylene copolymer, or poly(vinylidene chloride), preferably poly(vinylidene chloride). <Aspect 12> 12. The method according to any one of aspects 1 to 11, wherein the active portion of the membrane has a thickness of 5.0 μm to 240 μm, preferably 10 μm to 120 μm. <Aspect 13> 13. The method of any one of aspects 1 to 12, wherein the vapor barrier membrane further comprises a reinforcing or protective layer in contact with one of the outer layers of the active portion. <Aspect 14> 14. The method of any one of aspects 1 to 13, wherein a wall of the building or a wall of the room within the building is covered with insulation, and the vapor barrier membrane is applied in an internal position relative to the insulation or the membrane is integrated within the insulation. <Aspect 15> 15. The method of claim 14, wherein the insulating material is made of mineral or organic, natural, synthetic, or man-made fibers.

Claims

1. A method for improving the airtightness of a building or a room in a building, comprising using a vapor barrier membrane on an inner surface of a wall of the building or the room in the building, characterized in that the vapor barrier membrane is a humidity control membrane having a three-layer structure; The three-layer structure is an intermediate layer having a thickness between 2 μm and 200 μm and a water vapor permeability coefficient P １ and a water vapor permeability coefficient P １ increases with average relative humidity and is at least 300 Barrer when measured at 23°C and an average relative humidity of 25.5%; and on both sides of the intermediate layer, two outer layers, each having a thickness between 100 nm and 20 μm, and each having, independently of one another, a water vapor permeability coefficient P ２ and the water vapor permeability coefficient P ２ The maximum temperature for the two outer layers is 250 Barrers when measured at 23°C and an average relative humidity of 25.5%. Including, method.

2. The water vapor permeability coefficient P of the organic polymer constituting the outer layer ２ 2. The method of claim 1, wherein the average relative humidity (RRH) is not significantly affected by the RRH.

3. 3. The method according to claim 1 or 2, characterized in that the biopolymer forming the intermediate layer is a biopolymer of biological origin selected from the group consisting of oxides, proteins, and synthetic polymers obtained from monomers of biological origin.

4. 4. The method according to claim 3, characterized in that the oside is selected from the group consisting of alginic acid, carrageenan, cellulose, in particular regenerated cellulose, chitin, chitosan, pectin, dextrin, starch, curdlan, FucoPol, gellan gum, pullulan and xanthan.

5. 4. The method of claim 3, wherein the protein is selected from the group consisting of gluten, soy protein isolate, zein, whey protein, casein, collagen, and gelatin.

6. 6. The method of claim 4 or 5, wherein the oxides and proteins are cross-linked.

7. 4. The method according to claim 3, characterized in that the synthetic polymer obtained from monomers of biological origin is selected from the group consisting of polyhydroxyalkanoates (PHAs), polylactic acids (PLA), polyglycolic acids (PGA), poly(lactide-co-glycolides) (PLGA), polymers obtained by polymerization of lipid monomers, thermosetting polymers obtained by reaction of monosaccharides, disaccharides, oligosaccharides and / or alditols with polycarboxylic acids and / or polyaldehydes.

8. 3. The method according to claim 1 or 2, characterized in that the biopolymer is a biodegradable polymer selected from the group consisting of aliphatic polyesters, aliphatic copolyesters, aromatic copolyesters and polyesteramides.

9. 9. The method of claim 8, wherein the biodegradable biopolymer is selected from the group consisting of poly(caprolactone) (PCL), poly(butylene succinate) (PBS), poly(butylene succinate-co-adipate), and poly(butylene adipate-co-terephthalate) (PBAT).

10. 10. The method according to any one of claims 1 to 9, characterized in that the organic polymer constituting the outer layer is selected from the group consisting of polypropylene, polyethylene, poly(ethylene-co-propylene), homopolymers and copolymers of vinyl monomers, the vinyl monomers being selected from vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene and acrylonitrile.

11. 2. The method of claim 1, wherein the middle layer is made of cellulose and the two outer layers are made of polyethylene, polypropylene, ethylene-propylene copolymer, or poly(vinylidene chloride).

12. The method according to any one of claims 1 to 11, characterized in that the three-layer structure of the membrane has a thickness of 5.0 μm to 240 μm.

13. 13. The method according to any one of claims 1 to 12, characterized in that the vapor barrier membrane further comprises a reinforcing or protective layer in contact with one of the outer layers of the three-layer structure.

14. 14. The method according to any one of claims 1 to 13, characterized in that the walls of the building or the walls of the rooms in the building are covered with insulation and the vapor barrier membrane is applied in a position internal to the insulation or the membrane is integrated within the insulation.

15. 15. The method according to claim 14, characterized in that the insulation is made of mineral or organic, natural, synthetic or man-made fibers.

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