초록 ▼

The invention relates to a vapor retarder membrane, intended to be used for improving the airtightness of a building or of a room, comprising at least one active layer having a water vapor permeability which increases with the surrounding relative humidity, said active layer comprising at least 90%

The invention relates to a vapor retarder membrane, intended to be used for improving the airtightness of a building or of a room, comprising at least one active layer having a water vapor permeability which increases with the surrounding relative humidity, said active layer comprising at least 90% by weight of a blend of ethylene/vinyl alcohol (EVOH) copolymer and of a copolyamide 6-6.6 (PA666), the latter having a melting point below 210° C.

대표청구항 ▼

1. A vapor retarder membrane, comprising one active layer or an assembly of more than one active layer having a water vapor permeability that increases with surrounding relative humidity, wherein: said one active layer or assembly of more than one active layer comprises at least 90% by weight of a b

1. A vapor retarder membrane, comprising one active layer or an assembly of more than one active layer having a water vapor permeability that increases with surrounding relative humidity, wherein: said one active layer or assembly of more than one active layer comprises at least 90% by weight of a blend of ethylene/vinyl alcohol (EVOH) copolymer and of a copolyamide 6-6.6 (PA666) having a melting point below 210° C.,an EVOH/PA666 weight ratio in said blend is 10/90-50/50,the total thickness of the one active layer or the assembly of more than one active layer is 20-100 μm, andthe one active layer or the assembly of more than one active layer is at least 40% by weight of the vapor retarder membrane. 2. The vapor retarder membrane as claimed in claim 1, wherein the one active layer or the assembly of more than one active layer comprises at least 95% by weight of the blend of EVOH and of PA666. 3. The vapor retarder membrane as claimed in claim 2, wherein the one active layer or the assembly of more than one active layer consists essentially of the blend of EVOH and of PA666. 4. The vapor retarder membrane of claim 1, wherein the EVOH/PA666 weight ratio is 20/80-50/50. 5. The vapor retarder membrane of claim 1, wherein the membrane does not comprise another type of active layer or layers. 6. The vapor retarder membrane of claim 1, wherein an ethylene content of the EVOH is between 20 and 35 mol %. 7. The vapor retarder membrane of claim 1, wherein the PA666 is a random copolymer comprising PA6 units and PA66 units and having a PA6 unit/PA66 unit molar ratio of between 97/3 and 50/50. 8. The vapor retarder membrane of claim 1, wherein the total thickness of the one active layer or the assembly of more than one active layer is 25-80 μm. 9. The vapor retarder membrane of claim 1, further comprising a support layer or protective layer or both which is optionally peelable. 10. The vapor retarder membrane of claim 1, wherein the one active layer or the assembly of more than one active layer is more than 80% by weight of the membrane. 11. A process for manufacturing the vapor retarder membrane of claim 1, the process comprising heating and kneading, at a temperature of between 200° C. and 230° C., EVOH and PA666 until a homogeneous blend of these polymers is obtained, and forming a membrane from the homogenous blend of EVOH and of PA666. 12. The process as claimed in claim 11, wherein the forming of the membrane is by extrusion, mechanical drawing, calendering, and/or blow-molding of the polymer blend. 13. A process for improving airtightness of a building or of a room in a building, the process comprising applying the vapor retarder membrane of claim 1 to an internal face of a wall of said building or of said room. 14. The process as claimed in claim 13, wherein the applying comprises applying the membrane in an internal position relative to a thermal insulation material. 15. The vapor retarder membrane of claim 4, wherein the EVOH/PA666 weight ratio is 30/70-50/50. 16. A vapor retarder membrane, comprising an active layer having a water vapor permeability that increases with surrounding relative humidity, wherein the active layer comprises at least 90% by weight of a blend of ethylene/vinyl alcohol (EVOH) copolymer and of a copolyamide 6-6.6 (PA666) having a melting point below 210° C.wherein an EVOH/PA666 weight ratio in said blend is 10/90-50/50, andwherein the active layer is 50 μm thick, the PA666 is a random copolymer comprising PA6 units and PA66 units and has a PA6 unit-PA66 unit molar ratio of 85/15, the EVOH/PA666 weight ratio in the active layer is 30/70, and the ethylene content of the EVOH is 38 mol %. 17. The vapor retarder membrane as claimed in claim 16, wherein the active layer consists essentially of the blend of EVOH and of PA666. 18. The vapor retarder membrane as claimed in claim 1, wherein the vapor retarder membrane comprises one active layer. 19. The vapor retarder membrane as claimed in claim 1, wherein the vapor retarder membrane comprises the assembly of more than one active layer. 20. The vapor retarder membrane of claim 1, wherein the one active layer or the assembly of more than one active layer is at least 60% by weight of the vapor retarder membrane.