Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
  • C08L1/02—Cellulose; Modified cellulose
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/625—Sheets or foils allowing passage of water vapor but impervious to liquid water; house wraps

Definitions

• the present invention relates to a method for improving the airtightness of buildings or parts of buildings using a vapor barrier membrane, comprising a hydrophilic layer based on biopolymer and an adjacent layer relatively more hydrophobic than the layer to be used. biopolymer base.
• Such vapor barrier membranes having differentiated behavior depending on the surrounding relative humidity conditions are frequently described as “intelligent” (in English smart vapor retarder (SVR)).
• SVR smart vapor retarder
• a hygro-regulating vapor barrier membrane is generally considered to be all the more interesting and efficient as its equivalent air thickness is high at low relative humidity and low at high relative humidity.
• Membranes based on such biopolymers for example based on cellulose, chitosan or even based on poly(3-hydroxybutyrate) (PHB) are known and have been used, replacing films based on petrosourced synthetic polymers, in particular in the field of food packaging where membranes are generally required to have water vapor permeability relatively independent of humidity and temperature conditions.
• the lifespan of packaging films is quite limited and generally ranges from a few days to a few weeks, or at most a few months.
• a first layer with a thickness of between 2 pm and 200 pm made up of a biopolymer having a water vapor permeability coefficient Pi which increases with the average relative humidity and which, when determined at 23 °C and at an average relative humidity of 25.5%, is at least equal to 300 Barrers, and, on only one of the two faces of the first layer, preferably in contact with it,
• the active part of the membrane is preferably a two-layer structure consisting of the first biopolymer layer and the second layer of synthetic organic polymer, these layers being as defined above.
• the first biopolymer layer and the second synthetic organic polymer layer are of course continuous, non-perforated layers. They are therefore impermeable to fluids, whether liquid or gaseous.
• the permeability coefficients Pi and P2 are those of the polymers forming the first layer and the second layer respectively. They correspond to the ratio of the mass flow of water vapor (Q) which passes through an area (A) of a membrane of the polymer to be tested having a given thickness (E), under the effect of a difference in vapor pressure of water (dP) existing on either side of the membrane.
• the second synthetic organic polymer layer generally has a thickness less than that of the first biopolymer layer.
• the ratio of the thickness of the first layer to the thickness of the second layer is advantageously between 1.5/1 and 1000/1, preferably between 2/1 and 500/1, in particular between 3/1 and 200/1.
• the second layer of synthetic organic polymer is preferably directly in contact with the first layer of biopolymer, that is to say the interface between the layers is preferably free of adhesive.
• the layers defined above form the “active part” of the membranes of the present invention.
• This part is preferably a membrane obtained in a known manner by co-extrusion of thermoplastic polymers forming the different layers, by heat-sealing a film (second layer of synthetic organic polymer) on the biopolymer layer, or by deposition of a coating on only one of the two faces of the first biopolymer layer.
• the active part in principle has mechanical strength allowing it to be used alone, that is to say without a support layer, it can be interesting, in particular for active layers of low thickness (less than 50 pm), to reinforce it with a mechanical structure permeable to air and whose resistance to the diffusion of water vapor is therefore negligible compared to that of the active layer, impermeable to air.
• the vapor barrier membrane therefore further comprises an air-permeable reinforcement or protective layer, directly in contact with the active part, that is to say with one of the two layers constituting the active part.
• This support layer can be a grid, a perforated plate, an open porosity foam or an air-permeable woven or non-woven textile. It is preferably a breathable textile, preferably a non-woven fabric. Examples of particularly preferred support layers include nonwovens made of polypropylene or polyester fibers or glass fibers. The support layer(s) are preferably fixed to the active membrane, or active layer, by bonding using a polyurethane glue.
• the present invention also includes membranes where a reinforcing structure, such as a grid or a nonwoven, is incorporated in the active part of the membrane and more particularly in the first biopolymer layer or between the first biopolymer layer and the second layer of synthetic organic polymer.
• a reinforcing structure such as a grid or a nonwoven
• the water vapor permeability coefficient P2 of the organic polymer constituting the second hydrophobic layer does not vary significantly with the average relative humidity.
• the P2humid/P2dry ratio is generally between 1.0 and 1.10, preferably between 1.0 and 1.05.
• the biopolymers forming the first layer are biosourced and/or biodegradable organic polymers. They are preferably biosourced.
• biosourced biopolymers are preferably chosen from the group consisting of
• Osides include glycosides whose hydrolysis produces oses and non-carbohydrate compounds and holosides which are polymers exclusively of oses.
• saccharides which can be used to form the first biopolymer layer of the vapor barrier membrane of the present invention those chosen from the group consisting of alginate, carrageenan, cellulose, in particular regenerated cellulose (water hydrate). cellulose), chitin, chitosan, pectin, dextrin, starch, curdlan, FucoPol, gellan gum, pullulan and xanthan.
• the proteins are advantageously chosen from the group consisting of gluten, soy protein isolate, zein, whey proteins, casein, collagen and gelatin.
• biosourced polymers extracted from biomass, have a high affinity for water and dissolve or swell in water to form hydrogels.
• the first membrane is a vapor barrier membrane according to the invention. It consists of a first layer of cellulose with a thickness of 23.5 ⁇ m covered on one of its faces with a layer of poly(vinylidene chloride) (PVDC) with a thickness of 1.5 ⁇ m.
• PVDC poly(vinylidene chloride)
• the permeability coefficient Pi of the first cellulose layer is 5600 Barrers at a relative humidity of 25.5% (23 °C) and 34600 Barrers at a relative humidity of 90% (23 °C); the permeability coefficient P2 of the PVDC layer is 5 Barrers (23 °C). It does not vary depending on relative humidity.

Landscapes

• Chemical & Material Sciences (AREA)
• Architecture (AREA)
• Engineering & Computer Science (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Civil Engineering (AREA)
• Electromagnetism (AREA)
• Physics & Mathematics (AREA)
• Structural Engineering (AREA)
• Building Environments (AREA)
• Laminated Bodies (AREA)
• Polyesters Or Polycarbonates (AREA)
• Biological Depolymerization Polymers (AREA)
• Finishing Walls (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Cites Families (14)

• 2022
  • 2022-06-09 FR FR2205550A patent/FR3136491B1/fr active Active
• 2023
  • 2023-06-08 WO PCT/FR2023/050816 patent/WO2023237841A1/fr not_active Ceased
  • 2023-06-08 JP JP2024572359A patent/JP2025518400A/ja active Pending
  • 2023-06-08 EP EP23736163.9A patent/EP4536738A1/de active Pending

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