WO2014122385A1

WO2014122385A1 - Web of multilayer material made from cellular foam and textile fibres and associated production method

Info

Publication number: WO2014122385A1
Application number: PCT/FR2014/050187
Authority: WO
Inventors: Richard PAPIN
Original assignee: Société D'innovation De Recyclage Textiles Et Matériaux Alvéolaires "Innortex"
Priority date: 2013-02-06
Filing date: 2014-02-03
Publication date: 2014-08-14
Also published as: FR3001657B1; FR3001657A1

Abstract

A web of multilayer material (11) made from cellular foam characterised in that it comprises at least two adjacent layers: -at least one first flexible layer, called the foam layer (2), formed from an agglomerate of pieces of polyurethane or latex foam, and thermoplastic fibres, and optionally textile fibres, the pieces of cellular foam forming the majority component by weight of said foam layer, -at least one second layer, called the felt layer (3A, 3B), which is more rigid than the foam layer (2), containing a mixture of foam, textile fibres and thermoplastic fibres, the textile fibres being the majority component by weight of said felt layer, said adjacent at least one foam layer and at least one felt layer being (thermo)bonded together by means of the thermoplastic fibres present in each of the two adjacent layers and flush with the surface of each of them. The invention also concerns the method of producing the web of multilayer material.

Description

BAND OF MULTILAYER MATERIAL BASED ON ALVEOLAR FOAM AND TEXTILE FIBERS AND METHOD OF MANUFACTURING THE SAME

The present invention relates to the field of multilayer materials based on foam and textile, and their method of manufacture.

More particularly, the present invention relates to the recycling of materials resulting from the recovery of production falls, or the recovery of bedding elements, such as mattresses, or furniture elements, such as upholstery elements, seats, armchairs, sofas or the like, based on cellular foam and / or textile. The recycling of such elements is complex because it must integrate both the recycling of the "foam" part and that of the "textile" part, generally constituting the envelope of the foam-based elements.

In the recycling of materials from mattresses or furniture upholstery, the various elements of bedding or upholstered furniture upholstery are generally dismantled, followed by shredding of the foam-based elements. a fraying of the textile elements. The sorting of these different constituents is a long and tedious operation. An object of the present invention is therefore to propose the simultaneous recycling of these two categories of elements, by the manufacture of a material integrating both cellular foam waste and textile waste.

Another object of the invention is to provide a multilayer material incorporating both cellular foam waste and textile waste. Sheets of foamed foam material are already known comprising agglomerates of foam, pieces of foam larger or smaller, interconnected by thermoplastic fibers. Felt layers containing agglomerates of textile fibers and of thermoplastic fibers bonding textile fibers to one another are also known. The present invention relates to a strip of multilayer material based on cellular foam characterized in that it comprises at least two adjacent layers:

at least a first flexible layer, referred to as a foam layer, formed of an agglomerate of foam pieces, of polyurethane or latex type, and of thermoplastic fibers, and possibly of textile fibers, the pieces of cellular foam forming the majority weight component at least one second layer, called a felt layer, which is stiffer than the foam layer and which contains a mixture of foam, textile fibers and thermoplastic fibers, the textile fibers being the majority weight component of said foam layer; felt layer,

said at least one adjacent foam layer and at least one felt layer being (thermo) bonded together by means of the thermoplastic fibers present in each of the two adjacent layers and flush with the surface of each of them. The assembly of the layer (s) of foam and the (or) layer (s) of felt between them, does not require the introduction of an adhesive film or glue between them. The combination of these two types of layers, namely the assembly of a layer of foam and a layer of felt, has the advantage of combining the flexibility of the foam layer with the relative greater rigidity of the layer of felt. In addition, the foam layer is very light. Despite this lightness (low density), its combination with a felt layer gives it interesting properties, including improved performance of loss of height and hardness during dynamic fatigue tests.

The density of the cellular foam layer is advantageously less than 100 kg / m ³ , preferably less than 80 kg / m ³ , and more preferably less than 60 kg / m ³ . The felt layer advantageously has a grammage higher than 300 g / m ² and less than 1500g / m ^2, preferably between 500 and 1000 g / m ^2.

Advantageously, the second layer, called the felt layer, is of lesser thickness than the first layer, called the foam layer, in order to provide rigidity to said web of material without reducing the overall flexibility provided by the foam layer. The foam layer may for example be of a thickness of between 20 mm and 500 mm, more preferably between 30 mm and 240 mm. The thickness of the felt layer may be between 2 mm and 50 mm and preferably between 8 mm and 30 mm.

By textile fiber is preferably meant cotton or viscose fibers, as frequently encountered in bedding or upholstery furniture or seat components but any other textile fiber is usable in the process according to the present invention.

According to a first embodiment of the invention, the strip of multilayer material comprises at least two superimposed layers, one being a layer of foam and the other a layer of felt.

According to a second embodiment of the invention, the strip of multilayer material comprises at least three superimposed layers, one being at least one layer of foam disposed between at least two layers of felt. According to a third embodiment of the invention, the strip of multilayer material may comprise at least one layer of felt disposed longitudinally within a layer of foam, preferably in a corrugated or sinusoidal arrangement inside the layer. of foam, in particular for stiffening said foam layer.

The thermoplastic fibers used for the thermo-bonding between the constituents of the foam layer between the constituents of the felt layer, and between the different layers: felt and foam thus formed, are preferably polypropylene fibers or polyester fibers, such as polyethylene terephthalate (PET) fibers or poly (lactic acid) (PLA) fibers, or a combination of these fibers.

When the thermoplastic fibers are polyester fibers, the latter are preferably fibers of two-component type comprising a core housed in a sheath (peripheral envelope), the core having a softening point or higher melting than respectively the point of softening or melting of the sheath. For example, a bi-component polyester fiber having a softening or melting point sheath of about 100 to about 180 ° C and a softening or melting point core of greater than 200 ° C is suitable as a heat-setting fiber in the present invention.

Advantageously, the felt layer comprises a weight proportion of foam pieces of between 2 and 25%, preferably between 5 and 20%, more preferably between 6 and 10%.

Advantageously, the foam layer comprises a weight proportion of textile fibers of between 0 and 30%, preferably between 5 and 30%, more preferably between 5 and 25%. The proportion of thermoforming thermoplastic fibers may be equal or different in the different layers, preferably the at least one layer of foam and the at least one layer of felt comprise a proportion by weight of thermoplastic fibers of between 5% and 35%, preferably between 10% and 30%. The strips of multilayer material according to the invention can be configured and assembled according to an assembly in which said strips of multilayer material are arranged side by side, transversely or longitudinally, and are (thermally) bonded together by means of said thermoplastic fibers present in each of the at least two layers forming said adjacent strips and flush on the edge of each of them.

Weight ratios of minimum thermoforming fibers of 5% are preferred for good bonding of the multilayer strips juxtaposed. The present invention also relates to a method of continuously manufacturing strips of multilayer material as described above. This process comprises the following successive steps:

grinding pieces of foam to the desired size, preferably of size between 5 and 30 mm, preferably between 8 and 25 mm, more preferably between 10 and 20 mm; ii - elimination of the finest pieces of foam, namely less than 5 mm, preferably less than 2 mm;

iii- shredding and fraying of textile pieces to produce textile fibers; iv- mixing pieces of foam, textile fibers and thermoplastic fibers according to the weight proportions required to separately form at least one foam sheet and at least one felt sheet;

v- assembly of said plies of foam and felt by passing through an oven to achieve the softening of the thermoplastic fibers present within said plies, and thus the thermo-bonding of adjacent plies,

the passage through the furnace being accompanied and / or followed by an operation of compressing the assembly of said plies;

vi- cooling of the strip of multilayer material thus produced.

"Hot" compression strengthens the adhesion of materials between them and layers between them. This additionally provides the finished material web with static or dynamic fatigue stress resistance.

By grinding the pieces of foam is meant both the shredding of larger pieces but also the cutting to achieve fragments of more regular shapes by means for example of rotary scissors. These clean cuts can influence the quality of the foam layer. The mixture is more homogeneous, the arrangements of the pieces between them are more precise and can contribute to a better coefficient of expansion, and a better behavior of the material in terms of loss of height and hardness.

Foam webs and felt webs may be formed by a needling process, or advantageously by a process known as "air lay" in which the fibers are positioned and oriented with air ( for example, machine "air lay" of the manufacturer LAROCHE). This "air lay" method is preferred because it does not require mechanical intervention within the material, in contrast to the needling process using needles to place the fibers in the desired orientation.

Preferably, the formation of the web of felt takes place continuously, and the mixture of the components of the foam layer is deposited continuously on said web of previously formed felt before passing through the oven and compression.

Advantageously, the foamed materials and textiles used are derived from the recycling of bedding elements, such as mattresses, or upholstered furniture upholstery elements, such as seats.

Recycling means both the dismantling of mattresses or furniture or the recycling of manufacturing scrap. These recycled products used for the production of strips of multilayer material according to the invention can be reused for the realization of new upholstery or bedding materials. For this purpose, alternatively, during the deposition of the mixture of the components of the foam layer, spring-type springs for the mattress may be inserted. The strip of multilayer material, preferably according to the second embodiment of the invention, namely two layers of felt surrounding a layer of foam, itself enclosing spring elements, thus constitutes a strip of complete material that can be used directly. as a cushioning element in furniture (mattress core for example). It has the advantage of being able to be carried out continuously by means of the manufacturing method according to the invention.

The strips of multilayer material, according to the invention as well as the set of strips described above and prepared according to the method described above, find an interesting use as a sound and / or thermal insulator or as a material of padding.

The invention will be better understood on reading the following description of exemplary embodiments, with reference to the appended drawings in which: FIG. 1 is a sectional diagram of a strip of multilayer material according to the first embodiment of the invention. invention; Figure 2 is a sectional diagram of a strip of multilayer material according to the second embodiment of the invention; Figure 3 is a sectional diagram of a strip of multilayer material according to the third embodiment of the invention; FIG. 4 schematizes the method of continuous manufacture of strips of multilayer materials according to the invention; Figure 5 is a sectional diagram of a variant of the second embodiment of multilayer strips according to the invention; FIG. 6 is a diagram illustrating the method of producing the multilayer strip of FIG. 5.

With reference to FIGS. 1, 2 and 3, the strip of multilayer material (1; 1 1; 21) according to the invention consists of at least one layer 2 of cellular foam, and at least one layer felt 3; 3A, 3B; 3C.

The layer called felt layer 3 consists of an agglomerate, that is to say here a mixture as homogeneous as possible pieces of cellular foam, textile fibers and thermoplastic fibers. In this layer of felt, textile fibers are the majority weight component.

The layer 2, called foam, is an agglomerate, as homogeneous as possible mixture of pieces of foam, thermoplastic fibers and optionally textile fibers. The pieces of cellular foam constitute the majority weight component of this layer of foam 2.

The strip of multilayer material according to the invention can be presented in three different main aspects:

according to a first embodiment (shown diagrammatically in FIG. 1), a felt layer 3 and a foam layer 2 are superimposed and adhere to one another by means of the thermoplastic thermo-forming fibers contained in each of said layers to form the multilayer strip 1 1 ;

according to a second embodiment (shown diagrammatically in FIG. 2), at least one layer of foam 2 is interposed between two layers of felt 3A and 3B, the layers being bonded together by means of the thermoplastic fibers of thermobonding to form the multilayer strip 1 1;

according to a third embodiment of the invention (shown diagrammatically in FIG. 3), the multilayer strip 21 comprises a layer of foam 2 enclosing within it one or more layers of felt 3C arranged (for example) , as schematized in this figure 3, sinusoidally in the heart of said foam layer.

By way of example is shown schematically in Figure 4 the method of manufacturing a multilayer strip 1 1 having a layer of foam 2 disposed between two layers of felt 3A and 3B, that is to say according to the second embodiment of embodiment of the invention.

The starting materials of the felt layers are textile fibers, in particular frayed textile fibers from production residues or post-consumer products, for example bedding, agglomerated with a polyester-type thermolating fiber. The felt layer also incorporates pieces of foam, the whole is mixed, applied to an "air lay" type machine to form a sheet of felt which, after passing through an oven (such as the oven 6 of FIG. ), is compressed for the purpose of stabilizing the material, and after cooling into rolls 4A and 4B.

For the realization of the continuous process, as shown diagrammatically in FIG. 4, a first felt layer coming from the roll 4B is positioned on the conveyor 10 of the "air lay" type machine and will constitute the lower layer of felt 3B of the strip of multilayer material 1 1 final. The foam layer is made continuously on said lower felt layer 3B after mixing, thermo-forming fibers 7 with foam pieces 12 in a hopper 8, the mixture being spread on the lower felt layer 3B. Then a layer of felt 3A (top felt layer) from a second roll 4A is applied over the foam layer 5 thus formed.

The assembly then passes into the oven 6 to be heated in order to allow the thermoling fibers 7 to be softened to bind, on the one hand, to the other components of the foam layer and, on the other hand, to the layers of felt 3A lower and upper 3B between which it is positioned. A compression is preferably applied at the time of passage through the oven 6 when the assembly is still hot to form a strip of multilayer material 1 1 according to the invention. According to a variant of this method shown in FIG. 6, springs 9 can be positioned in the thickness of the foam layer 2 to form the strip of multilayer material 31 shown in FIG. 5. These springs 9 can be in the form of a spring plate inserted into the mixture of foam and fibers before compression; they may be plastic springs or steel-type metal springs. In the latter case, the metal springs are first integrated in a non-woven bag which allows them to be associated with each other to form a plate, that is to say a set of poly-springs.

By way of examples, the constituents used for the different layers of felt and foam may be:

- textile fibers, viscose fibers and / or cotton of length ranging between 10 mm and 80 mm. Here the textile fibers are advantageously derived from recycling of bedding material for example which comprises both textile fibers and cellular foam. In this case, it may be that the textile fiber mixture also contains a fraction of reduced size foam flakes during the fraying phase. A hygienization phase can be implemented prior to the use of these materials. added polyester thermoloading fibers represent a proportion by weight of between 5 and 35%, preferably between 10% and 30% of the total weight of the felt layer and between 5 and 35%, preferably between 10 and 30%; % of the total mass of the foam layer. The thermolating fiber is preferably a bi-component polyester fiber composed of a core and a shell called sheath. The sheath melts at a temperature close to 1 10 ° C while the core can withstand temperatures of about 200 ° C. The softening of the sheath thus makes it possible to ensure the sticky power, also called the thermoliant, of these fibers. Preferably, these fibers have a linear weight between 2.2 and 20 decitex and a length of between 15 and 60 mm approximately. the foam layer is an agglomerate of flakes of polyurethane foam or latex which may be derived from the production residues of a foam plant or plant using these materials, or from material from post-furnishing products. consumption for example. In the latter case, a hygienization phase is implemented prior to the use of these foam flakes. These foam flakes are prepared by a grinding process, for example by means of a knife mill, equipped with a grid with 15 mm round or square holes. This grinding makes it possible to obtain a size of flakes or pieces of approximately 15 mm, the fine particles being thus eliminated.

After the coating and thermolysis phase, the foam layer 2 may, for example, have a thickness of between 20 mm and 250 mm. Its density may advantageously be between 20 and 50 kg / m ³ approximately, depending on the degree of compression. The layer (s) of felt can (wind) have a thickness of between 2 mm and 50 mm, preferably between 8 and 30 mm for use in bedding or furniture, with a basis weight of between 300 g / m ² and 1000 g / m ² .

Exemplary embodiments and results of physicochemical characterizations are presented below.

Example 1

A strip of multilayer material is prepared according to the method described above. The different layers are composed as follows:

Comparative samples: the foam layers consist of 80% by weight of an agglomerate of recycled polyurethane foam pieces from dismantled mattresses, mixed with 20% of low-melt polyester bicomponent fibers (hot-melt sheath at 110 ° C. - Manufacturer Far Eastern) (fibers of 32 mm length, 4 denier). Different densities of foam are prepared corresponding to more or less significant compressions of the web during the passage in the oven (T ° = 170 ° C) according to a continuous operation on a conveyor at an average speed of about 1.2 m. min. The densities of the three foam layers A, B and C manufactured are summarized in Table 1. a sample according to the invention combines a 12 cm thick layer of foam A having a density of 25 kg / m ³ , and a layer of felt of thickness e = 10 mm and a weight of 800 g / m ² .

This felt layer comprises an agglomerate of recycled textile fibers (75% by weight), recycled foam (5% by weight) and 20% by weight of the same two-component polyester fibers as those used for the foam layers of the samples. comparative.

In order to reuse such a band (foam + felt) in the field of bedding, dynamic fatigue tests according to the IS03385 standard have been carried out. The results of these tests are summarized in Table 1. Dynamic fatigue tests according to ISO 3385

Table 1 It is noted that the presence of felt associated with the foam layer of 25 kg / m ³ has a beneficial effect on the loss of thickness of the latter by reducing this loss by more than 8 mm, that is to say say of a third.

Regarding the loss of hardness, the ISO 3385 standard which imposes, for use of bedding material, a hardness loss of less than or equal to 25% is observed for foams B and C.

For the foam A it is the addition of the felt layer which allows to pass the threshold of the 25% loss of hardness. The combination, according to the invention, of a layer of foam with a layer of felt thus makes it possible to obtain interesting mechanical properties, in particular for use in the field of bedding.

Example 2

A strip of multilayer material, prepared according to the same method as Example 1, combines a layer of foam A 30 mm thick having a density of 25 Kg / m ³ surrounded by two layers of thick felt e = 10 mm and weight of 800 g / m ² . The content of volatile organic compounds of this multilayer material was measured according to ISO 16000 methods (-3, -6, -9, -1 1) on a sample of 1 m ² of multilayer material with a total thickness of 50 mm.

The volume of the emitting chamber is 1 m ³ with a charge rate of 1 m ² / m ³ and a renewal of air of 0.5 m ³ / h. The incoming air is dried over activated silica gel and filtered by means of a VOC filter.

The samples taken on 200/400 carbon tube and DNPH 300/150 silica tube are analyzed by GC-MS (VOC) and HPLC (Aldehydes). The sample volume at 3 and 28 days is 90 liters at 60 l / h.

The VOC content of this multilayer material is shown in Table 2 below: Concentration μ9 / η "ΐ A +

VOC Total <244 <1000

1,4-Dichlorobenzene nd <60

2-Butoxyethanol nd <1000

Acetaldehyde 1, 56 <200

Ethylbenzene nd <750

Formaldehyde 4.96 <10

Styrene nd <250

Tetrachlorethylene nd <250

Toluene <20 <300

Trimethylbenzene nd <1000

Xylene nd <200 nd: not detected

Table 2 These results show that the multilayer material according to the invention has very low total VOC values (<250 micrograms / m ³ ), which makes it possible to classify it as A + material for its VOC labeling, ie to say in the highest class. This demonstrates that the multilayer material according to the invention, comprising no glue or adhesive between the foam layer and the felt layers, makes it possible to obtain a material with a very low content of Volatile Organic Compounds.

Example 3 - Physical Characterizations ase yq \ um i q ue ap a rente

On the same type of material prepared as that of Example 2, tests were carried out to characterize the apparent density of this material according to EN 1602.

On different test specimens, the value of the average density calculated is of 49.75 Kg / m ³ . This value is close to that of polyurethane panels (of the order of 40 Kg / m ³ ), rock wool (of the order of 40 Kg / m ³ ) and cellulose wadding medium density (from the order of 55 Kg / m ³ ) (see Table 3). Stabi! dj.mens ion nej I

Characterization tests for dimensional stability under different temperature and humidity conditions were carried out according to EN 1604 and EN 1604 / A1. Three test pieces (A, B and C) were measured after a succession of climatic conditions as indicated below:

- 48 hours at 5 ° C (+2) and 15% (+5) HR

- 48 hours at 25 ° C (+2) and 50% (+5) HR

- 48 hours at 50 ° C (+2) and 90% (+5) HR

(RH = Relative Humidity)

The results are given in Table 3 below:

Table 3

The dimensional variations (thickness, length and width) are very small despite the temperature and hygrometry conditions imposed. The insulation is stable over time. Thermal nductjyjt

The thermal conductivity of the wet or dry sample was also measured by the guarded hot plate method, which is one of the most widely used steady-state measurement methods.

The thermal conductivity measured on dry material (stabilized at 10 ° C) is 0.03563 W / mK and the thermal conductivity on a wet material (stabilized at 50% relative humidity and at 20 ° C) is 0.3593 W / mK.

The difference is therefore very small between the thermal conductivity of the wet material or the dry material. These thermal conductivity values are close to those of expanded polystyrene, polyester, glass wool, cellulose wadding in bulk or panel or sheep wool (see Table 4).

Acoustic absorption

The acoustic absorption performance of the material is also very good. The absorption coefficient is greater than 0.8 from 800 Hertz, which is comparable to values obtained with commonly used acoustic materials (mineral wool, foam).

Resuspension.to.ready already in use. (D) Finally, water vapor diffusion resistance tests according to standard NF EN 12086 after having placed the samples in an air-conditioned room at 23 ° C (+2) and 50% (+ 5) relative humidity (RH) stipulated in the standard for several weeks.

For the tests, the samples were placed under the following conditions:

- 23 ° C - 1 1/50% RH (saturated NaOH solution / room regulated at 50% RH) - 23 ° C - 54/80% RH (with a saturated solution in K ₂ CO ₃ / oven at 80% RH ) - 23 ° C - 80 / 99.5% RH (with a saturated solution in K ₂ S0 ₄ / oven at 80% RH) The evolutions of the masses of the samples tested were also checked all throughout the tests. The samples lost or gained barely 1% in mass during the three months of tests. The samples are therefore not hydrophilic.

The mean values of resistance to water vapor diffusion (μ, m ² .h.Pa / mg) and water vapor permeability (δ, mg / mhPa) were calculated for the following conditions: : 23 ° C - 54/80% RH and 23 ° C - 80 / 99.5% RH and are respectively -0.9 and 0.06. These values are very close to those obtained for rockwool, in particular (see Table 4). The set of results of the physical characterizations of the multilayer material according to the present invention as well as the comparison with other insulators are presented in the summary table 4 below.

If the values of apparent density and thermal conductivity are taken into account, it can be deduced that the multilayer material according to the present invention has properties very close to those of rockwool, cellulose wadding and wood fiber.

A use of the multilayer material according to the invention in the fields of thermal and acoustic insulation can thus be envisaged.

Claims

1. Strip of multilayer material based on cellular foam characterized in that it comprises at least two adjacent layers:

at least a first flexible layer, referred to as a foam layer (2), formed of an agglomerate of pieces of foam, of polyurethane or latex type, and of thermoplastic fibers (7), and optionally of textile fibers, the pieces of foam cellular membrane forming the majority weight component of said foam layer; - at least one second layer, referred to as a felt layer, which is stiffer than the foam layer and which contains a mixture of foam, textile fibers and thermoplastic fibers, the textile fibers being the majority weight component of said felt layer,

said at least one layer of foam (2) and at least one adjacent layer of felt (3; 3A, 3B; 3C) being (thermo) bonded together by means of the thermoplastic fibers present in each of the two adjacent layers and flush with the surface of each of them.

2. strip of multilayer material according to claim 1 characterized in that the second layer, called felt layer, is of lesser thickness than the first layer, said layer of foam, to provide rigidity to said strip of material without reducing its general flexibility provided by the layer of foam (2).

3. strip of multilayer material according to any one of claims 1 or 2 characterized in that it comprises at least two superposed layers one being a layer of foam (2) and the other a layer of felt (3) .

4. Strip of multilayer material according to any one of the preceding claims, characterized in that it comprises at least three superposed layers, one being at least one layer of foam (2) disposed between at least two layers of felt (3A , 3B).

5. strip of multilayer material according to claim 1 characterized in that it comprises at least one layer of felt (3C) disposed longitudinally within a layer of foam, preferably in a corrugated or sinusoidal arrangement within the layer of foam (2), in particular for the purpose of stiffening said layer of foam.

6. A strip of multilayer material according to any one of the preceding claims, characterized in that the thermoplastic fibers (7) are polypropylene fibers or polyester fibers, such as polyethylene terephthalate (PET) fibers or poly fibers ( lactic acid) (PLA), or a combination of these fibers.

7. strip of multilayer material according to claim 6 characterized in that the polyester fibers are bi-component type fibers comprising a core housed in a sheath, the core having a softening or melting point higher than the point respectively softening or melting of the sheath.

8. strip of multilayer material according to any one of the preceding claims, characterized in that the felt layer comprises a weight proportion of foam pieces of between 2 and 25%, preferably between 5 and 20%, preferably between 6 and 10%.

9. A strip of multilayer material according to any one of the preceding claims, characterized in that the foam layer (2) comprises a textile fiber weight proportion of between 0 and 30%, preferably between 5 and 30%, preferably still between 5 and 25%.

Multilayer material web according to one of the preceding claims, characterized in that the at least one layer of foam (2) and the at least one layer of felt comprise a proportion by weight of thermoplastic fibers (7) of between % and 35%, preferably between 10% and 30%, the proportion of thermoplastic fibers may be equal or different in the different layers.

1 1. Set of strips of multilayer material characterized in that said strips of multilayer material according to any one of the preceding claims are arranged side by side, transversely or longitudinally, and are (thermally) bonded together by means of said thermoplastic fibers (7). ) present in each of the at least two layers forming the said strips adjacent and flush on the edge of each.

12. A method of continuous manufacture of strips of multilayer material according to one of the preceding claims comprising the following successive steps:

grinding pieces of foam to the desired size, preferably of size between 5 and 30 mm, preferably between 8 and 25 mm, more preferably between 10 and 20 mm;

ii - elimination of the finest pieces of foam, namely less than 5 mm, preferably less than 2 mm;

iii-shredding and fraying of textile pieces to produce textile fibers; iv- mixing pieces of foam (12), textile fibers and thermoplastic fibers (7) according to the weight proportions required to separately form at least one foam web and at least one felt web;

v- assembly of said plies of foam and felt by passing through an oven (6) to achieve the softening of the thermoplastic fibers present within said plies. and thus the thermo binding of adjacent layers,

the passage in the furnace being accompanied and / or followed by a compression operation of the assembly of said plies

vi- cooling of the strip of multilayer material thus produced.

Method according to claim 12, characterized in that the formation of the felt web takes place continuously, and in that the mixture of the components of the foam layer is continuously deposited on said felt web (previously formed). , before the passage in the oven and compression.

14. Method according to any one of claims 12 or 13, characterized in that the foamed materials and textiles used are derived from the recycling of bedding elements, such as mattresses, or padded furniture upholstery elements, such as than seats.

15. Method according to any one of claims 12 to 14, characterized in that during the deposition of the mixture of the components of the layer of foam are inserted spring-like springs for mattress.

16. Use of strips of multilayer material according to any one of 1 to 10, of the set of strips according to claim 1 1 or prepared according to the method of claims 12 to 14 as a sound insulator and / or thermal.

17. Use of strips of multilayer material according to any one of claims 1 to 10, the set of strips according to claim 1 1 or prepared according to the method of claims 12 to 15 as padding material.