METHOD FOR PRODUCING A SOUND-ABSORBING PANEL

Abstract

Method for producing of a sound-absorbing panel, including a step of preparing a predetermined amount of cellulose fibres and a step of immersing the cellulose fibres in a first water basin to form a cellulose pulp. The method then includes a step of preparing a predetermined amount of textile fibres and a step of mixing, in water, the cellulose pulp with the textile fibres to obtain a final pulp and a step of depositing the final pulp on a forming mould. The method then includes a step of pressing at least the final pulp in order to cause an at least partial removal of the water contained in the final pulp making a fibre mat and a step of drying the fibre mat so as to cause evaporation of the water remained in the fibre mat making a sound-absorbing panel.

Claims

1. A method for producing a sound-absorbing panel, the method comprising the steps of: preparing a predetermined amount of cellulose fibres; immersing the cellulose fibres into a first water basin to form a cellulose pulp; preparing a predetermined amount of textile fibres; mixing, preferably in water, said cellulose pulp with said textile fibres to obtain a final pulp; depositing said final pulp on a forming mould; pressing at least said final pulp in order to cause at least partial removal of the water contained in the final pulp making a fibre mat; drying said fibre mat so as to cause evaporation of the water remained in said fibre mat making a sound-absorbing panel.

2. The method according to claim 1, wherein the method comprises, prior to the mixing step, a step of removing a predetermined amount of cellulose pulp from said cellulose pulp, and wherein in the deposition step, said final pulp is deposited on the mould to define a lower layer and said removed cellulose pulp is deposited on said lower layer to define an upper layer.

3. The method according to claim 2, wherein during said pressing step a mixing sub-step occurs wherein, near an interface surface between the upper layer and the lower layer, part of the final pulp is at least partially amalgamated with part of said removed cellulose pulp defining an interface layer interposed between said lower and upper layer.

4. The method according to claim 1, wherein the method comprises, prior to said step of preparing a predetermined amount of textile fibres, a step of shredding textile material, preferably said textile material being waste textile material, to obtain the textile fibres.

5. The method according to claim 1, wherein said textile fibres are heterogeneous fibres, preferably said textile fibres comprising one or more among: cotton; wool; polyamides; polyester.

6. The method according to claim 1, comprising a step of adding at least one dye in said first water basin so as to give a predetermined colouring to the cellulose pulp, preferably said at least one dye being a natural dye.

7. The method according to claim 1, wherein prior to the mixing step, the method comprises a step of immersing the textile fibres into a second water basin to form a fibre pulp, and wherein in said mixing step, said cellulose pulp is mixed with said fibre pulp to obtain said final pulp.

8. The method according to claim 7, comprising a step of adding at least one dye in said second water basin so as to give a predetermined colouring to the fibre pulp, preferably said at least one dye being a natural dye.

9. The method according to claim 7, wherein said at least one dye is a powder dye, preferably the dye having a particle size between 20 m and 80 m.

10. The method according to claim 1, wherein said cellulose fibres have a length between 0.5 mm and 5 mm.

11. A sound-absorbing panel made according to the method claimed in claim 1, having a density value between 100 Kg/m.sup.3 and 700 Kg/m.sup.3, preferably said density value being between 150 Kg/m.sup.3 and 350 Kg/m.sup.3.

12. Use of textile fibres to make a pulp to obtain a sound-absorbing panel according to claim 11.

Description

[0026] Such description will be set forth herein below with reference to the accompanying drawings, provided for merely indicative and therefore non-limiting purposes, wherein:

[0027] FIG. 1 shows a schematic of a first embodiment of the method covered by the present invention;

[0028] FIG. 2 shows a schematic of a second embodiment of the method covered by the present invention;

[0029] FIG. 3A shows a front plan view of a sound-absorbing panel obtained using the method shown in FIG. 1;

[0030] FIG. 3B shows a rear plan view of a sound-absorbing panel obtained using the method shown in FIG. 1;

[0031] FIG. 4A shows a front plan view of a sound-absorbing panel obtained using the method shown in FIG. 2;

[0032] FIG. 4B shows a rear plan view of a sound-absorbing panel obtained using the method shown in a FIG. 2.

[0033] The method for producing a sound-absorbing panel F, which is the subject of the present invention, comprises a step of preparing a predetermined amount of cellulose fibres.

[0034] Preferably, cellulose fibres have a length between 0.5 mm and 5 mm.

[0035] Preferably, the average length of cellulose fibres is between 1.3 mm and 2.5 mm.

[0036] Advantageously, the length of the cellulose fibres used in the method of the present invention makes the cellulose easier to be processed.

[0037] The method further comprises a step of immersing the cellulose fibres in a first water basin 100 to form a cellulose pulp P1.

[0038] In this situation, the cellulose fibres are dispersed in water so as to form the cellulose pulp P1.

[0039] In accordance with a possible embodiment, the method comprises a step of adding at least one dye in the first water basin 100 in order to give the cellulose pulp P1 a predetermined colouring.

[0040] In other words, if a predetermined colouring is to be imparted to the final sound-absorbing panel F, a dye is added to the water of the first basin 100 in which the cellulose fibres are immersed to form the cellulose pulp P1 so that the latter absorbs the dye.

[0041] Preferably, the dye used is a natural type of dye, e.g. a mineral origin dye.

[0042] Preferably, the dye is a powder dye with a particle size, for example, between 20 m and 80 m.

[0043] Preferably, the dye consists of kaolin and at least one additional component.

[0044] For example, iron oxide and manganese oxide can be mixed with the kaolin to give it a sienna, i.e. red, colouring.

[0045] For example, calcium, manganese and iron carbonates can be mixed with the kaolin to give it a black colouring.

[0046] Advantageously, the use of natural dyes enables the production of coloured and, at the same time, safe sound-absorbing panels F. In particular, natural dyes eliminate the problems resulting from possible harmful inhalation from formaldehyde-based resins used in the prior art.

[0047] In addition, the use of natural dyes lowers the environmental impact of the whole process of making sound-absorbing panels F as they are easier to dispose of and non-toxic.

[0048] The method further comprises a step of preparing a predetermined amount of textile fibres V.

[0049] Preferably, the method comprises, prior to the step of preparing a predetermined amount of textile fibres V, a step of shredding textile material from which textile fibres V are obtained.

[0050] Preferably, the textile material from which these textile fibres V are obtained is a waste textile material.

[0051] Advantageously, the use of a waste textile material makes the obtained panel F eco-friendly as it avoids the waste of such textile material that would otherwise have to be disposed of.

[0052] Preferably, these textile fibres V are heterogeneous fibres.

[0053] Even more preferably, textile fibres V comprising one or more of: cotton; wool; polyamide; polyester.

[0054] Following the step of preparing textile fibres V, the method comprises a step of mixing, preferably in water, the cellulose pulp P1 with textile fibres V to obtain a final pulp P3.

[0055] In this situation, the final pulp P3 is formed from the cellulose pulp P1 into which the textile fibres V have been mixed i.e. a mixture in which cellulose pulp P1 and textile fibres V have been mixed.

[0056] While the cellulose pulp P1 mixes with textile fibres V, textile fibres V bind to the cellulose fibres of the cellulose pulp P1. The cellulose fibres of the cellulose pulp P1 act as binders. In this situation, there is no need to add any kind of synthetic/chemical binder as it is the cellulose fibres of the cellulose pulp P1 that act as binders for the entire panel V.

[0057] Advantageously, using cellulose fibres as a binder, it is possible to avoid adding synthetic binders, making the panel F easier to manufacture and, above all, to dispose of.

[0058] Advantageously, the panel F is completely recyclable, e.g. the panel F can be introduced into water to obtain the final pulp P3 and proceed to form a new panel F.

[0059] After the final pulp P3 is obtained, the latter is deposited on a forming mould 300.

[0060] Preferably, the forming mould 300 has, in section, the shape to be given to the final sound-absorbing panel F.

[0061] Following the distribution step, the method comprises a step of pressing the final pulp P such that at least part of the water it contains is removed and a fibre mat T is created.

[0062] In other words, during the pressing step, the final pulp P3 is crushed and squeezed so as to remove the water incorporated therein and so as to give the final pulp P3 the desired shape for the final sound-absorbing panel F.

[0063] By way of example, FIG. 1 and FIG. 2 show a press in which the lower half-mould is the forming mould 300 and in which an upper half-mould is moved closer to the lower half-mould in order to press the final pulp P3 and make the fibre mat T.

[0064] Preferably, the method comprises a step of collecting water resulting from the pressing step.

[0065] In more detail, during the pressing step, when the water contained in the final pulp P3 is expelled, it is collected, e.g. in a container to be disposed of. In such a situation, in case a dye has been added during the immersion steps, as it is natural, the disposal of the water could be carried out in a simple and environmentally friendly manner by a settling process.

[0066] Following the pressing step, the final pulp P3 was squeezed to remove water and was deformed to form a fibre mat T.

[0067] In this situation, the method comprises a step of drying the fibre mat T so as to cause evaporation of the water remained in the fibre mat T itself making the sound-absorbing panel F.

[0068] Preferably, the drying step takes place at a temperature between 25 C. and 40 C.

[0069] Preferably, at the end of the drying step, the method comprises a step of applying an aqueous solution containing a waterproofing element on at least one surface of the sound-absorbing panel F.

[0070] At the end of the drying step, and possibly of the application step, the panel obtained has a first and a second face like those shown in FIG. 3, wherein the textile fibres V drowned within the cellulose fibres are visible.

[0071] In accordance with the embodiment of the method shown in FIG. 2, on the other hand, the method comprises, prior to the step of mixing the pulp P1 with the textile fibres V, a step of removing a predetermined amount of cellulose pulp P1 from the cellulose pulp P1 itself.

[0072] In other words, before the cellulose pulp P1 is mixed together with the textile fibres V, part of the cellulose pulp P1 is extracted and kept aside.

[0073] In this situation, in the deposition step, the final pulp P3 is deposited on the mould 300 to define a lower layer I. Subsequently, the removed cellulose pulp PR is also deposited on the mould 300, and in particular on the lower layer I, to define an upper layer S.

[0074] In other words, once the final pulp P3 is deposited on the mould 300, the removed pulp PR is deposited on the third pulp P3 so that there is a lower layer I and an upper layer S.

[0075] After the final pulp P and the removed pulp PR have been deposited on the mould 300, the pressing step takes place to allow the water contained in the final pulp P3 and the removed pulp PR to escape.

[0076] During the pressing step, a mixing sub-step occurs wherein, near an interface surface between the upper layer S and the lower layer I, part of the final pulp P3 amalgamates at least partially with part of the removed pulp PR defining an interface layer interposed between the lower and upper layers I, S.

[0077] Thanks to the aforementioned mixing, the lower and upper layers I, S are bound together with no need to add any resin and/or chemical binder.

[0078] Furthermore, by layering the final pulp P3 and the removed pulp PR, it is possible to obtain a panel F, shown in FIG. 4, having: [0079] a coarser face, given by the lower layer I defined by the final pulp P3 in which the textile fibres V mixed with cellulose fibres are visible; [0080] a second face, opposite the first face, which is smoother and more homogeneous, given by the upper layer S defined by the removed pulp PR wherein there are no textile fibres V but only cellulose fibres.

[0081] In other words, following the drying step, it can be seen that the panel F has a smooth face defined by the pressed and dried cellulose fibres alone, and a face on which the textile fibres V bound and mixed with the cellulose fibres are recognisable.

[0082] According to a further embodiment of the method (not shown), following the textile fibre V preparation step, the method could comprise a step of immersing the textile fibres V in a second water basin to form a fibre pulp.

[0083] In this situation, at the mixing step, the cellulose pulp P1 is mixed with the aforementioned fibre pulp to obtain the final pulp P3.

[0084] In other words, the pulp P1 and fibre pulp are mixed together in water in order to obtain the final pulp P3 from a mixture of the pulp P1 and fibre pulp.

[0085] In accordance with this embodiment, the method could further comprise a step of adding at least one dye in the second water basin in order to give the fibre pulp a predetermined colouring.

[0086] Preferably, as was the case with the first water basin 100, a natural dye, e.g. a mineral dye, is used in the second water basin.

[0087] In this case as well, preferably, the dye is a powder dye with a particle size of, for example, 20 m to 80 m.

[0088] Preferably, the dye consists of kaolin and at least one additional component.

[0089] It is possible that only the cellulose pulp P1 may be coloured. Alternatively, only the fibre pulp is coloured.

[0090] Alternatively, both the cellulose pulp P1 and the fibre pulp are coloured. In the latter case, the cellulose pulp P1 and the fibre pulp may be coloured the same colour or different colours.

[0091] Once the cellulose pulp P1 and the fibre pulp have been mixed together, the steps of the method are identical to those described above for the embodiments shown in the attached figures.

[0092] A sound-absorbing panel F made in accordance with the method described above is also an object of the present invention.

[0093] The sound-absorbing panel F thus produced has a density value between 100 kg/m.sup.3 and 700 kg/m.sup.3, preferably between 150 Kg/m.sup.3 and 350 Kg/m.sup.3.

[0094] The sound-absorbing panel F thus produced has a sound-absorption value between 0.4 w and 1 w.

[0095] It is also an object of the present invention to use textile fibres to make a pulp to obtain a sound-absorbing panel F as described above.

[0096] In other words, textile fibres V are used to make a sound-absorbing panel F in accordance with the foregoing.

[0097] The present invention achieves the intended purposes overcoming the drawbacks of the prior art.

[0098] The use of textile fibres V mixed with cellulose fibres avoids the introduction of glues, solvents, resins or any other non-natural and toxic material/substance into the panel F as the textile fibres V are bound with the cellulose fibres.

[0099] Furthermore, the fact that no adhesives and/or chemical dyes are used makes both the manufacturing process and the use of the sound-absorbing panel F safe for health.

[0100] The use of textile fibres V makes the panel F eco-friendly as waste textile fibres V are used and given new life in an industrial process.