A sound absorbing membrane and use thereof

Abstract

The present invention concerns a membrane for absorbing sound and / or vibration, such as in an underlay or the like in a floor structure of a building, said membrane comprising a first polymeric film having an exterior side and an interior side; a second polymeric film having an exterior side and an interior side; and a matrix layer formed between said first polymeric film and said second polymeric film, said matrix layer comprising a non-woven net of recycled granulate material and matrix fibres, wherein said matrix fibres being polymeric fibres bonded to the interior side of the first polymeric film and to the interior side of the second polymeric film, thereby entrapping the granulate material and forming a matrix of channels of air in the matrix layer.

Description

[0001] A SOUND ABSORBING MEMBRANE AND USE THEREOF

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a membrane for absorbing sound and vibration.

[0004] BACKGROUND OF THE INVENTION

[0005] In buildings, it is known that flooring underlayment equalizes imperfections in the subfloor, softens and cushions the floor covering to make the floor easier to walk on, protects against moisture, and provides some sound insulation. Foam, cork, and rubber are common soft underlayments.

[0006] From US 2022 / 0105701 Al and W02008 / 145131A1 it is known to upcycle shredded granular material to form a non-woven fibrous mat. The mat comprises a large first portion of recycled shredded material, where the shredded material is a mixture of shredded fabric material fibres from automotive tires or the like and residues of rubber and other components from the shredded tires, and a small second portion of bi-component fibres. It is known to use a mat of this type as an underlayment. It is advantageous as such type of underlay is inexpensive in manufacturing and environmentally sustainable due to the recycling of rubber materials. The mat of this type has good sound absorbing characteristics.

[0007] However, in relation to floor structures and especially the sub-floor structures, the installation height may be of importance and a low installation height is of preference. This can be difficult to achieve in particular when the floor is provided with heating where the sub-floor construction also needs to accommodate heating elements.

[0008] It is an object of the present invention to provide a membrane for a thin underlay that allows for a low building height in a floor construction, in particular a subfloor, and which nevertheless has good sound absorbing characteristics. It may be another object to provide a membrane for this type of use which is easy to manufacture and to install on the building site.

[0009] SUMMARY OF THE INVENTION

[0010] This object is achieved in a first aspect of the invention by providing a membrane for absorbing sound and / or vibration, such as in an underlay or the like in a floor structure of a building, said membrane comprising a first polymeric film having an exterior side and an interior side; a second polymeric film having an exterior side and an interior side; and a matrix layer formed between said first polymeric film and said second polymeric film, said matrix layer comprising a non-woven net of recycled granulate material and matrix fibres, wherein said matrix fibres being polymeric fibres bonded to the interior side of the first polymeric film and to the interior side of the second polymeric film, thereby entrapping the granulate material and forming a matrix of channels of air in the matrix layer.

[0011] In the membrane according to the invention, the granulates are distributed in the matrix layer between the fibres and the fibres form a matrix web where the fibres extend between the two polymeric films, i.e. the top to the bottom surfaces of the matrix layer thereby entrapping the granulates between the fibres and retaining them in the web. Thus, the fibres has a length that reaches from the one exterior film to the other. A majority of the particles of granulate material have a particle size which is almost equal to the thickness of the matrix layer, which means that a very thin matrix layer and in turn a relatively thin membrane can be achieved. The fibres are bonded to the polymeric films on either sides of the matrix layer by subjecting the matrix layer to a thermal heat treatment to form the bonding.

[0012] By entrapping the granulate particles in the matrix web of fibres a series of irregular air channels are created within the matrix layer so that sound waves may disappear or at least be significantly reduced inside the matrix web, and thereby not travel from one side of the membrane to the other but rather be dispersed into the numerous small air pockets in the matrix. Hereby, sound and vibrations can be absorbed in the thin membrane according to the invention. Advantageously, the granulate material is one or more of recycled granular rubber, or cork such as shredded tires from automotive vehicles or the like. This type of material is typically regarded as waste material and therefore an inexpensive and very suitable material for producing a sound absorbing membrane of the kind to which the present invention pertains.

[0013] By the invention, it is realised that the membrane can be used for a variety of purposes within the building industry. Besides using the membrane as a panel in a sub-floor structure of different kinds, the membrane according to the invention may be advantageous as acoustic dampening webs in wall constructions or the like.

[0014] In the preferred embodiments, the polymeric matrix fibres are bi-component fibres, fibres of thermoplastic material and / or a combination thereof. Hereby, the fibres can contribute to the creation of strength by being adhered to the outer first and second polymeric films, as the matrix layer is provided with a heat treatment during the manufacturing of the membrane.

[0015] In an embodiment of the membrane according to the invention, the non-woven net of the matrix layer comprises 1-5% by weight polymeric fibres and 95-99 % by weight of granular material. This provides for a porous and cohesive matrix layer which possesses good sound and vibration dampening characteristics.

[0016] It is found advantageous that in the membrane according to the invention the thickness of the matrix layer is between 1.0 and 5.0 mm. Accordingly, the particle size of the granulate material in the matrix layer is preferably in the range of 0.5 to 5.0 mm, more preferably approx. 1.0 mm. Hereby, the matrix layer density may be 50-1000 kg / m3, preferably approx. 200-500 kg / m3. This allows for a significant amount of air being trapped inside the matrix layer and the advantageous sound absorbing structure can be achieved. The polymeric films on either sides of the matrix layer are thin films with a very small thickness, such as 25-200 pm, for instance approx. 40-60 pm, such as LDPE, PET or aluminium films. Preferably the overall thickness of the membrane is between 1.0 and 5.0 mm. Hereby, a low installation height is achieved. In the present disclosure, the particle size of the granulate material may also be referred to as granular size.

[0017] In one embodiment, the exterior side the polymeric first film is provided an aluminium foil. In a further embodiment thereof the exterior side of the second film may also be provided an aluminium foil. Hereby, thermal reflection of the membrane may be achieved. Depending on the intended use of the membrane in a building construction, the membrane may be provided with a reflective aluminium foil on both sides or only on one of the sides.

[0018] In an embodiment of the invention, said exterior side of the first and / or second polymeric film is further provided with an adhesive layer with a removable protective liner thereon. In particular, the adhesive layer may be provided on any one of the exterior sides with the aluminium foil layers thereon. Hereby, a self- adhesive membrane may be provided, which makes it easy to handle and position in a building structure, such as a sub-floor.

[0019] In an advantageous embodiment of the invention, the polymeric first film is provided with a polymeric layer which may be a woven or non-woven layer of polyethylene stands or fibres, and / or where said polymeric layer has a surface texture suitable for one of the two materials in a hook and loop fastener system (Velcro®) to be adhered thereto. This is advantageous since it is hereby possible to mount building elements in a simple manner without having to use e.g. nails, clamps or brackets that require penetrating the membrane. Such building elements may be for instance mounting tubes, wires or the like for a floor heating installation in a sub-floor structure.

[0020] The membrane is advantageously made gas impermeable and thereby suitable for use as a vapour barrier in the sub-floor structure.

[0021] In one series of embodiments, the layer structures on the first and second polymeric films are the same (but mirrored). Alternatively, the layer structures on the first and second polymeric films may be different depending on the type of membrane required. In a second aspect of the invention there is provided an advantageous use of the membrane according to the first aspect, in a building structure, in particular as a sound and vibration dampening insulation panel in a floor structure. A particularly advantageous use of the membrane according to the first aspect is where the membrane is further provided with an adhesive layer and that the membrane is adhered to a floor substrate for the provision of a damp proof barrier in the floor structure.

[0022] DETAILED DESCRIPTION

[0023] In the following, the invention is described in more detail with reference to the embodiments shown in the accompanying drawings, in which:

[0024] Fig. 1 is a schematic view of a first embodiment of the invention;

[0025] Fig. 2 is a close up detailed schematic view of the section A in fig. 1;

[0026] Fig. 3 is a schematic view of a second embodiment of the invention;

[0027] Fig. 4 is a schematic view of a third embodiment of the invention, and Fig. 5 is a schematic perspective view of an embodiment of the invention.

[0028] In the figures schematic illustrations of embodiments of a membrane according to the invention are shown. As can be seen, the membrane is made up of a number of layers in a laminated structure around a matrix layer 1. In fig. 1 a schematic side view of the membrane according to one embodiment of the invention is shown. In fig. 2, there is shown a detailed view of the section A marked in fig. 1 showing the matrix layer 1 of the membrane. The matrix layer 1 comprises a mixture of granulate particles 2 and thermoplastic fibres 3 and a first polymeric film 4 and a second polymeric film 5 making up the two exterior sides of the membrane and having the matrix layer 1 between these two polymeric films 4, 5 (see fig. 2). Different compositions of the top layers 6-9 on either side can be provided. Different examples thereof are shown in figures 1, 3, 4 and 5.

[0029] The matrix layer is formed in an air-laid non-woven forming system whereby the granulate 2 is entangled in the network of fibers 3. In the matrix 1 formed, the granular particles 2 are irregularly distributed in this network of fibers 3, as shown in fig. 2. This air-laid matrix 1 is thus formed as web and is then provided with thin films on either side. The polymeric films 4, 5 on either sides of the matrix layer 1 are thin films 4, 5 such as LDPE, PET or aluminium films, with a very small thickness, such as 25-200 pm, for instance approx. 40-60 pm. The films are thermoplastic films 4, 5 and by advancing the matrix layer 1 sandwiched between the films 4, 5 through a heat zone in the production equipment, a thermal bonding is established between the fibres 3 in the matrix 1 and the polymeric films 4, 5 whereby the matrix layer 1 becomes a cohesive construction.

[0030] The material of the granulate particles 2 is preferably one or more of recycled granular rubber, such as shredded automotive tires or the like, cork or wood granules. The polymeric matrix fibres 3 may be bi-component fibres, fibres of thermoplastic material and / or a combination thereof. The matrix layer 1 comprises preferably 1-20 % by weight polymeric fibres and 80-99 % by weight of granular material. The net of fibres formed in the matrix entraps the granulate particles 2 but does also create an irregular network of air channels therein. This allows for a relatively light-weight membrane product. The matrix layer density is 50-1000 kg / m3, preferably approx. 200-500 kg / m3, depending on the type of granulate material. For instance, if cork is the predominant material the density will be in the lower region of the indicated ranges and if recycled rubber material is the granular material the density of the matrix will be in the upperpart of the indicated ranges.

[0031] The overall thickness of the membrane is essentially about the same as the particle size of the granulate 2, for instance between 1.0 and 5.0 mm. Accordingly, the granular particle size of the granulate material 2 in the matrix layer 1 may be in the range of 0.5 to 5.0 mm, more preferably approx. 1.0 mm.

[0032] In an embodiment of the membrane according to the invention, the first polymeric film 4 is provided with a polymeric layer 6, which may be a woven or non-woven layer for providing stiffness or the like to the membrane (see figs. 1 and 3). The polymeric layer 6 may be made of polyethylene stands or fibres, and as shown in fig. 3, said polymeric layer may be provided with a surface texture 10 suitable for one of the two materials in a hook and loop fastener system (Velcro®) to be adhered thereto. This is advantageous since it is hereby possible to mount elements, e.g. mounting tubes, wires or the like for a floor heating installation in a sub-floor structure, in a simple manner without having to use clamps, brackets or the like that require penetrating the membrane in order to fix the element to the sub-floor.

[0033] In advantageous embodiments, at least one side of the matrix 1, the exterior side the polymeric film 5 is provided an aluminium foil 7. As shown in figures 1, 3 and 5, one side is provided with an aluminium foil 7. Hereby, thermal reflection of the membrane may be achieved which may improve the insulation properties of the membrane when installed in a sub-floor structure or the like.

[0034] Depending on the intended use of the membrane in a building construction, the membrane may also be provided with such a reflective aluminium foil 7 on both sides of the matrix layer 1 as shown in fig. 4.

[0035] In an embodiment of the invention, said exterior side of the first and / or second polymeric film 4, 5 may be provided with an adhesive layer 8 with a removable protective liner 9 thereon (see figures 1, 3 and 5). In particular, the adhesive layer 8 may be provided on the exterior side of the aluminium foil layer 7 (see fig. 5). Hereby, a self-adhesive membrane may be provided, which makes it easy to handle and position in a building structure, such as a sub-floor.

[0036] By the invention it is realised that the layer structures on the first and second polymeric films 4, 5 may be the same (but mirrored) as shown in fig. 4, or alternatively, the layer structures on the first and second polymeric films 4, 5 may be different (see fig. 1, 3 and 5) depending on the type of membrane required.

[0037] The membrane according to the invention may advantageously be utilised as a sound and vibration dampening insulation panel in a building structure, such as a sub-floor structure. The membrane is also advantageous when it is further provided with an adhesive layer so that the membrane is adhered to a floor substrate for the provision of a damp proof barrier in the floor structure. As a further use of a membrane according to the invention, it is realized that a membrane having double sided adhesive layers can be used as sound proofing in wall constructions, such as in between two boards of gypsum or plywood. The invention is described above with reference to some currently preferred embodiments. However, by the invention it is realised that other embodiments and variants may be provided without departing from the scope of the invention as defined in the accompanying claims.

Claims

CLAIMS1. A membrane for absorbing sound and / or vibration, such as in an underlay or the like in a floor structure of a building, said membrane comprising a first polymeric film having an exterior side and an interior side; a second polymeric film having an exterior side and an interior side; and a matrix layer formed between said first polymeric film and said second polymeric film, said matrix layer comprising a non-woven net of recycled granulate material and matrix fibres, wherein said matrix fibres being polymeric fibres bonded to the interior side of the first polymeric film and to the interior side of the second polymeric film, thereby entrapping the granulate material and forming a matrix of channels of air in the matrix layer.

2. A membrane according to claim 1, wherein the granulate material is one or more of cork, wood granules, or recycled granular rubber, such as shredded tires from automotive vehicles or the like.

3. A membrane according to claim 1 or 2, wherein the polymeric matrix fibres are bi-component fibres, fibres of thermoplastic material and / or a combination thereof.

4. A membrane according to any one of the preceding claims, wherein the nonwoven net of the matrix layer comprises 1-20 % by weight polymeric fibres and 80-99 % by weight of granular material.

5. A membrane according to any one of the preceding claims, wherein the thickness of the matrix layer is between 1.0 and 5.0 mm.

6. A membrane according to any one of the preceding claims, wherein the granulate material in the matrix layer has a granular particle size in the range of 0.5 to 5.0 mm, more preferably approx. 1.0 mm.

7. A membrane according to any one of the preceding claims, wherein the matrix layer density is 50-1000 kg / m3, preferably approx. 200-500 kg / m3.

8. A membrane according to any one of the preceding claims, wherein the first and second polymeric films on either sides of the matrix layer have a thickness of 25-200 pm, preferably approx. 40-60 pm.

9. A membrane according to any one of the preceding claims, wherein the exterior side at least one of the first and second polymeric films is provided an aluminium foil.

10. A membrane according to any one of the preceding claims, wherein both the exterior sides of the first and second polymeric films are provided an aluminium foil.

11. A membrane according to any one of the preceding claims, wherein said exterior side of the first and / or second polymeric film is / are further provided with an adhesive layer with a removable protective liner thereon.

12. A membrane according to any one of the preceding claims, wherein the first polymeric film is provided with a polymeric layer which may be a woven or nonwoven layer of polyethylene stands or fibres, and where said polymeric layer preferably has a surface texture suitable for engagement with one of the two materials in a hook and loop fastener portion (Velcro®) for said faster portion to be adhered to said surface textured polymeric layer.

13. A membrane according to any one of the preceding claims, wherein the layer structures on the first and second polymeric films are the same (but mirrored) or the layer structures on the first and second polymeric films are different.

14. Use of a membrane according to any one of the preceding claims, in a building structure, in particular as a sound and vibration dampening insulation panel in a floor structure.

15. Use according to claim 14, where the membrane is further provided with an adhesive layer and that the membrane is adhered to a floor substrate for the provision of a damp proof barrier in the floor structure.

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