NL8602132A - SELF-BEARING SANDY SOUND DAMPER ELEMENT. - Google Patents

Description

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Self-supporting sandwich-like soundproofing element

The invention relates to a self-supporting, sandwich-like soundproofing element with two spaced apart, different cover layers and a core layer consisting of synthetic foam, which is arranged between them, and a method for manufacturing such a soundproofing element.

Many different sound-damping elements are already known for use in construction, in the damping of air sound, contact sound and step noise, as well as with other sound sources, such as motors, compressors and the like. A known soundproofing coating - according to DE OS 3334273 - comprises an absorption layer of open-pore plastic, on which a coating is applied on both sides. A mass layer with perforations is provided within the absorption layer. Between the one covering layer and the mass layer, the material of the absorption layer is more rigid, i.e. it has a lower modulus of elasticity than the less stiff layer between this mass layer and the other layer, which therefore has a higher modulus of elasticity. Such a sound-damping coating is provided with plate elements to avoid air and contact sound radiation. For this purpose, the soundproofing coating is applied directly to the sound-emitting surfaces, whereby a cover layer associated with the absorption layer is formed by this plate. However, such soundproofing coatings can only be used to a limited extent, since they can only reduce the sound emission of plate elements.

Furthermore, a sound insulation element is known - according to DE-OS 28 18 252 - which comprises a bend-slack intermediate layer arranged between two cover layers. The two cover layers have different hardnesses and the softer cover layer is used for the damping of the sound-damping element. transmitting the sound effect to sound-transmitting surfaces of this surface, that is to say on the side of the sound-damping element facing away from the sound.

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In order to further strengthen the soundproofing element, inlays may be provided locally or over the entire surface in at least one cover layer. Although it is possible to reduce the sound radiated from surfaces passing through sound 5, the application of these sound-damping elements could not, however, meet the requirements set in all application cases.

In a further known sound-absorbing element - according to AT-PS 373 948 - a lattice of wire, which is supported at least on edge areas, is connected to a foam body. This grating serves simultaneously to fix the sound absorption element, in which the ends of the grating projecting outside the foam body are suspended in profiles of a suspension construction. Although it was advantageous to avoid resonance phenomena of the support members carrying the sound absorption element, the sound damping values achieved were not, however, sufficient for all areas of application.

A building element for room sound insulation is also known - according to AT-PS 373 949 - in which a foam layer is connected to a hard plate of mineral fiber. The mineral fiber board can moreover be covered on its side facing the foam layer with a layer of kraft paper. Although the use of a hard mineral fiber board allowed the mechanical strength of the building element to be increased, an adaptation of the building element to different applications was also not possible in the desired size here.

The present invention now aims at providing a self-supporting, sandwich-like sound-damping element, which can be easily adapted to various application requirements. In addition, the application of the sound-damping element, in particular in motor vehicles, for damping the sound transmission between the engines and the parts radiating outward from the sound or between the parts radiating from the sound and the interior of the vehicle must be 32 * - 3 - * s are possible. In addition, the soundproofing element must be easy to manufacture.

This object of the invention is achieved in that the core layer has an increasing thickness in the direction of the two cover layers and consists of a plastic with predominantly open cells. Due to the densification of the cell structure in the two edge areas of the core layer, good anchoring of the cover layers and favorable vibration behavior of the multilayer, self-supporting sandwich-like soundproofing element A is achieved due to the different vibration characteristics of the denser edge areas. In the less dense middle region of the core layer, a multi-part vibration system is formed, which damps sound with different frequencies each time and achieves good overall operation, in particular when damping sound emitted by motors or compressors. Moreover, this plastic, which is also designated as foam plastic, with predominantly open cells, offers good protection against injuries when people collide with it, and is therefore also well suited for use in interior coatings of passenger vehicles and cabs for trucks. Surprisingly, however, the invention achieves a sufficient strength for normal operation because of the high density in the region of the two cover layers, the advantage of the invention still being that the thickness and also the density of the the top layer adjoining compacted edge area of the core layer can be easily adapted to different requirements.

According to another feature of the invention, the densified cell structure in the edge areas facing the two cover layers is formed by a mechanically and, respectively, or thermally compacted, open-cell plastic foam. The advantage of this solution lies in the fact that a uniform material with substantially the same expansion properties is obtained, which remains air-permeable, in order to achieve better sound insulation. In addition, it is advantageous that this compaction can take place in a process independent of the manufacture of the plastic foam, and thus the permanent deformation of the open-cell material by the action of pressure and temperature can be accurately dependent on the desired application criteria. regularly. Another advantage of this process under pressure and temperature, respectively, lies in the fact that in many cases it is possible to simultaneously perform a spatial deformation of the sound-damping element, including of the two cover layers, in order to achieve the desired spatial formation, such as is necessary for the manufacture inner lining 10 in motor vehicles.

According to another favorable embodiment variant, the specific gravity of the open-cell plastic foam of the core layer in the middle region and the edge region is different, the edge region preferably having one to two times as much spatial weight as the middle region. In this way it is advantageously prevented at the same time that a breakage of the cover layers or the sound-damping element is not caused when a force, in particular a sharp object, is applied.

However, it is also possible that the middle region is formed from a soft foam material, in particular with a specific gravity of about 9 to 10 kg / m, because in addition to the good sound-damping behavior of the elastic material, this also provides a highly damping effect upon impact of persons on such coated surfaces due to the elastic flexibility of the core layer is achieved.

According to another favorable further development, the core layer consists of a predominantly open-cell soft foam, in particular an MDI-driven or cross-linked polyether or polyester plastic foam. Such foams are distinguished by high elasticity and wear resistance and have proven themselves for the new field of application.

According to another feature of the invention, the core layer in the peripheral areas facing the two cover layers comprises a densified cell structure, which has a higher proportion of closed cells, than the cell structure in an intermediate region between these peripheral regions. The higher closed cell content and the densified cell structure provide greater resistance to the transmission of airborne noise, thereby slowing the propagation speed and facilitating its damping in the subsequent less dense but softer region of the core layer.

Furthermore, it is advantageous if the soft foam material consists of an, in particular MDI-driven, cross-linked polyether or polyester-plastic foam, respectively, and the core layer is preferably formed by a part of a soft foam block, since this provides an accurate open-cell structure with a low specific gravity can be achieved and a consistently high continuity of the cell structure over the thickness of the core layer is achieved.

Furthermore, it is also possible that the core layer consisting of middle and edge regions is designed in one piece, so that the number of separate parts for the manufacture of the soundproofing element according to the invention can be advantageously reduced.

However, it is possible that the cover layer is moisture-resistant, in particular as a polyethylene film, and the open cells of the edge region of the core layer are connected to the ambient air through openings in the cover layer or the adhesive layer or the polyethylene film, respectively. whereby the capillary action of the core layer with open cells is counteracted, while the moisture penetrated into this core layer can still escape as water vapor.

On the other hand, however, it is also possible that the moisture-repellent cover layer or the polyethylene film is provided on the side facing away from the core layer in front of a fiber mat with high-temperature-resistant fibers or threads 35 which have openings distributed over the surface, and has a particularly net-shaped design, so that the sound-proofing elements can also be arranged in the vicinity of sound sources emitting higher temperatures, and BS02132 «-ψ - 6 - and moreover there is a better protection against mechanical damage of the sound-damping element. Due to the reinforcement of the edge area associated with this fiber mat, a large part of the conspicuous sound is already absorbed when this part of the soundproofing element penetrates and it is ensured that the air for the soundproofing is also unhindered by the accessibility and air permeability of this fiber mat. the soundproofing element may end up.

It is furthermore advantageous here if the fibers or wires are formed by glass fibers and respectively or carbon fibers and / or metal fibers, since such fiber or wire mats allow a high mechanical and also thermal load and also against the influence of oil and fats are resistant.

According to another embodiment variant, on the surface of the other covering layer facing away from the fiber mat, a mat of water-repellent fiber web and of foam material, for instance an open-cell soft foam, is applied, the thickness of which is less than the thickness of the core layer, so that the the open-cell structure, the sound waves penetrated by the sound penetrating to the surface to be protected, are additionally attenuated before coming into contact with this surface.

It is furthermore advantageous if the individual regions of the core layer mutually and, respectively, or the covering layer with the core layer and, respectively, or the covering layer with the mat applied for it and, respectively, or fiber mat, by an adhesive layer, in particular with the cells. of the core layer and the adhesive layer is made air-permeable, the adhesive layer preferably forming the covering layer, since this does not impede the absorption capacity of the core layer by the adhesive layers present between the individual layers of the sandwich-like soundproofing element. , in the case of a connection of the layers only with the cell frame, the supply to the open cells in the core layer is further facilitated.

It is also advantageous if the adhesive layer 8602132 A * - 7 - is formed by the polyethylene foil, which is designed as a melting foil, since this simplifies the connection of the individual layers by eliminating the application of the adhesive.

However, it is also possible that an elastically deformable support body is provided in the core layer and, respectively, or in the region between the core layer and the fiber mat or mat, which is made air-permeable and / or sound-permeable in the direction of the cover layers. Sound-damping elements constructed in the same manner can easily be adapted to complicated spatial formation, such as, for example, to the internal shape of hoods or the like, and to be attached to such parts by the supporting bodies enabling this design.

According to another embodiment variant, an elastic, in particular permanently deformable, supporting body has been added to the core layer and is thereby connected in a force-transmitting manner and, respectively, in terms of shape. Therefore, the deformation properties of the similarly manufactured sound-proofing elements can be adapted to the various application requirements and at the same time suitable tear-resistant fastening points can be formed therein.

Furthermore, it is also possible that the core layer 25 is two-part and each time consists of a plate, between which the elastically deformable support body is arranged, in particular glued, since it can also be made of two plates when the support body is applied within the core layer. each consisting of a part r * 30 of a block of soft foam.

According to another embodiment variant, the carrying body and, respectively, the adhesive layer and, respectively, the covering layer and, respectively, the fiber mat and, respectively, the mat, are made water-permeable. This prevents deterioration in the operation of the soundproofing element due to moisture.

According to the invention it is also possible for the fiber mat to face a sound source and the 8602132 f - 8 - mat mounted on the opposite top side to the part to be protected, whereby the sound-damping element is between the sound source and a house surrounding it, for example a bonnet is fitted and is connected to it by means of a carrying body, whereby a sound-insulating fastening of the sound-damping element on surfaces to be protected, such as for instance the plate parts of a bonnet or the like, is possible without additional means.

It is also advantageous if a thickness of the middle region differs in relation to the thickness of the two edge regions of the core layer, but preferably three times as great as that of the edge regions, since the thickness of the different regions of the 15 core layer, an adaptation to the damping of different frequencies of sound waves is possible.

On the other hand, however, it is also possible that the specific gravity of the plastic foam of the core layer differs in the middle region and the edge regions, however preferably the edge region has twice as high specific gravity as the middle region, so that in addition the damping characteristic of the sound-damping element is with respect to the damping frequencies and at the same time a protection of the very soft middle region against mechanical damage is achieved in a simple manner.

According to another embodiment, the number of open cells in the central region and in the peripheral region of the core layer is different and in particular increases from the peripheral region in the direction towards the central region, resulting in labyrinth-like corridors in which the sound energy decreases.

Furthermore, it is also possible that a coating facing an edge region of the core layer is formed by a material or foil-shaped, deformable material, and the coating facing the other edge region is formed by a non-woven fabric and, or, in particular, an unsaturated polyester resin cardboard 8602132 * - 9 - is formed and is preferably deformable under temperature or pressure and is designed or curable.

By the use of two flexible and deformable, flat cover layers, a sandwich element is formed, which, due to the connection of the three materials, has a greater strength than each individual material in front of it. Moreover, through the suitable design of the cover layers, it can be achieved that during the deformation a permanent profiling of the sound-damping element occurs, and thus the formation of sound-damping characteristics can be combined with the design into one-single operation.

According to another embodiment variant, it is also possible, however, that an adhesive layer is provided between the covering layer and the core layer, which layer is preferably formed by a polyethylene film in the form of a melting foil and the core layer and, respectively, either the adhesive layer and, respectively, the support body and, respectively, or one or both cover layers are made air-permeable, in particular moisture-resistant. This ensures that, due to the air permeability, a good sound-absorbing effect of the sound-damping element is achieved at the same time and a long service life, since the liquid Hear the liquid-repellent design of the covering and / or adhesive layers.

Another embodiment of the invention is advantageous according to which at least one of the cover layers and or at least one of the two edge regions is provided with a moisture-repellent additional impregnation. Since the respective cover layers and edge areas 30 are provided with a moisture-resistant impregnation, which is preferably activated by the heating during the deformation of the elements, an impermissible moisture absorption of the sound-damping elements and thus a reduction of the sound-damping effect can be prevented in a simple manner.

Furthermore, it is also possible that the core layer has distributed over the surface, differently highly compacted surface areas, preferably the weight of the core layer relative to the same surface area and the corresponding thickness in the differently highly compacted surface areas. are about the same size. This embodiment variant has the great advantage that for the manufacture of sound-proofing elements according to the invention plate-shaped material with a uniform thickness as. starting material can be used. Thereby, in a surprisingly favorable manner, during the manufacture of the soundproofing elements according to the invention, a different compaction is established in those 10 surface areas, which are compacted to a smaller or larger wall thickness. Thus, thinner surface areas are more compacted and thus obtain a higher specific gravity and a greater strength than thicker surface areas of these plates. Indirectly, an automatic adaptation of the strength properties to the different thicknesses, as is usually necessary with lining elements for the interior lining of vehicles, is thus achieved.

However, the invention also comprises a method for manufacturing such sound insulation elements, in which a plastic core layer with different cover layers is joined in a force-transmitting manner.

This method is characterized in that a block of foam of soft foam is foamed and divided into plates, after which heat is supplied to the facing surfaces of one or two directly adjacent plates, in particular simultaneously, and these with a compressive force directed towards the middle layer and the edge areas of the plates are plastically deformed. Due to the heat and pressure treatment of the foam plates, it is possible to achieve different densities and cell structures in a one-piece element.

According to another method variant, for the heat supply between the facing surfaces of two plates, an adhesive layer or an adhesive foil and optionally a support body, in particular a wire grid or the like, is introduced. By simultaneously applying the coatings during this heat treatment, an additional gluing operation for attaching these to the surface of the edge areas of the core layer can be saved.

However, it is also advantageous if, due to the effect of the warrate, coatings are simultaneously applied to the mutually facing surfaces of the core layer and bonded thereto in a force-transmitting manner, one covering layer being formed by a fiber mat and the other covering layer by a mat.

Furthermore, it is also possible that the core layer and the supporting body are deformed spatially during the action of heat and force, since this reduces the cover for the production of the core layers and, moreover, can make a more uniform cell structure over the entire thickness of 15 "of the plate. then insured with separate manufacture of the plates.

However, it is also advantageous if heat-sealable plastic films are placed on the surfaces for heating and compacting the edge areas of the plates and are joined to the edge areas of the core layer by the heat and force action, since the heat effect during the compaction of the edge areas at the same time the melting or fixing of the moisture-sealing plastic films is achieved.

However, it is also possible that the magnitude and duration of the force action as well as the magnitude and duration of the temperature action can be changed depending on the desired damping behavior of the plate and in particular be the same in both edge regions. By controlling the method criteria such as the magnitude and duration of the force action and the temperature effect, the proportion of closed cells in the peripheral areas as well as the density and specific gravity can be adapted to the desired damping characteristics.

It is also advantageous if the fiber mat applied near the one covering layer and the mat applied near the other covering layer are applied simultaneously and are joined to the facing surfaces of the covering layers, since this causes the plates to warp as well as the formation of internal stresses is avoided.

A further method variant is characterized in that at least a part of the core layer having the same thickness, preferably jointly with at least one top layer, is molded while inserting an adhesive layer, in particular a polyethylene melting film, and with simultaneous action of pressure and temperature in different surface areas to different thicknesses are densified and the individual layers are simultaneously interconnected and respectively or cured, after which the sound-damping element is preferably cut to the desired circumferential shape in the same processing step. However, the advantages of the good sound attenuation and of the favorable behavior in the event of an accident due to the good attenuation properties of such elements when people collide with them are maintained.

For a better understanding of the invention, it will be explained in more detail below with reference to the illustrative embodiments shown in the drawings.

Figure 1 shows a sound-damping element constructed according to the invention in perspective, simplified, schematic representation;

Figure 2 shows a section through an edge region of a core layer of a sound-damping element according to the invention, in which the connection points with a schematically indicated covering film and the areas where the adhesive is applied to the cell structure are visible.

Figure 3 shows a front view of an engine compartment with sound-damping elements according to the invention arranged on the inside of the engine-compartment, as well as the mounting devices of these sound-damping elements on the hood.

Figure 4 shows a sound-damping element according to the invention in perspective view.

Figure 5 shows a cross-section through another sound-damping element in top view.

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Figure 6 shows a part of the core layer of a sound-damping element according to the invention, with a schematic perspective view showing the different cell structures in the compacted edge and in the middle region.

Figure 1 shows a self-supporting, sandwich-like sound-damping element 1. This sound-damping element 1 comprises two cover layers 2, 3 and a core layer 4.

In the present exemplary embodiment 10, the core layer 4 consists of two plates 5,6 of a soft foam, which, as schematically indicated, have a lower density in a central region 7 of the core layer 4 than in the edge regions 8, 9 of the core layer 4. In the central embodiment 7 of the core layer 4, a supporting body 10, for example a wire grid or a wire net or the like, is arranged between the facing surfaces of the two plates 5 and 6. The supporting body 10 is preferably elastic and can be permanently deformed into arbitrary spatial shapes by the action of pressure.

An adhesive layer 11 is provided for connecting the two plates 5, 6 and the support body 10, which layer can also be formed, for example, by a melting foil, for example a polyethylene foil or the like.

In the edge regions 8, 9, a fiber mat 14 and a mat 15, which form the cover layers 2, 3, are also connected to the plates 5, 6 by means of an adhesive layer 12, 13.

The adhesive layer 12, 13 may again be formed by melt foils, such as, for example, a polyethylene foil or the like. When using polyethylene films as adhesive layers, these are preferably provided with openings distributed over the surface, so that an air passage between the plates 5, 6 and these plates 5, 6 and the fiber mat 14 and the mat 15, respectively, is ensured. The use of the openings 16 allows the air in the cells of the plates to pulsate, so that the airborne sound vibrations are damped through the labyrinth-shaped passages in the open cell structure of the 3602132 - 14 - core layer 4 and the plates 5, 6 of these forming respectively. . In addition, through these openings 16 it is ensured that any gaseous moisture which has penetrated into the sound-damping element 1 can exit its gaseous state, but with a suitable choice of the size and the number of the surface unit 16 openings penetrated. of water in liquid form can be avoided as much as possible.

For mounting the soundproofing element 1, holders 17 are attached to the supporting body 10, which co-act with connecting means 18 to fix the soundproofing elements 1 to a part 19, which must be protected against the sound effects of a sound source 20. The connecting means 18 can for instance be formed by fixed pins or bolts or the like fixed to part 19.

Fibers or wires 21 of the fiber mat 14, respectively, can also be formed by high-temperature-resistant glass fibers, metal fibers, depending on the purpose of application of the sound-damping element, in particular in the vicinity of sound sources emitting higher temperatures, such as motors, compressors or the like. or carbon fibers or the like. By such an embodiment of the fiber mat, the adhesive layer 12 as well as the edge region 8 are protected against the action of too high temperatures.

The mat 15 arranged on the part 19 - which is arranged on the side of the sound-damping element facing away from the sound source 20 - is formed, for example, by a non-woven fabric or by a mat of soft foam material. The covering layer 2 and the fiber mat 14 and the covering layer 3 and the mat 15 respectively have a thickness 22 and 23 respectively, which is a part of a thickness 24 of the core layer 4. The mat 15 can be formed by a water-repellent fiber web or by a foam mat of a soft foam with predominantly open cells.

As indicated by the schematic representation of the middle area 7 and the edge areas 8, the core layer 4 has an increasing density in the direction of the two cover layers 8602132-15.2. While the middle layer preferably has a specific gravity of 10 kg / m, the specific gravity of the soft foam in the edge regions 8, 9 is about 18 to 20 kg / m. As a result, different sound transmission values are achieved over the thickness of the core layer 4, so that approximately equally good sound attenuation values for different frequencies are achieved with one sound attenuation element 1. Moreover, due to the higher specific gravity in the edge regions 8, 9, a greater strength and stability of the core layer 4 in the edge regions 8, 9 is achieved. This provides favorable conditions for the attachment of the cover layers 2, 3 to the core layer. Due to the greater strength of the edge areas 8, 9, the sound-absorbing element can be made self-supporting without additional measures, only by connection to the cover layers. It has been found to be advantageous if the different specific gravity of the edge regions 8, 9 relative to the middle region 7 of the core layer 4 is achieved in that plates of the same thickness are compacted in the edge regions by the action of pressure and temperature. Due to the breakdown of the open-cell cell structure due to the effect of temperature in these densified regions, a greater number of closed cells are created than in the central region 7. Due to a suitable change in the thickness of the edge region 8, 9 and the spatial weight in In relation to the space weight of the middle region 7, an adaptation of the sound-damping element to different sound sources or different frequencies of the sound waves emitted from such sound sources can be achieved. Preferably, plates are used for the core layer, which are cut from a block of soft foam. The soft foams used for the production of the plates may be polyether or polyester plastic foam, which is cross-linked or cross-linked, respectively, in an MDI-driven manner. The advantage of using plates cut from a block of plastic foam lies in that the density and the cell structure are as uniform as possible.

Within the scope of the invention it is irrelevant whether the core layer 4 consists of a single plate or two plates 5 and 6, as shown in figure 1, or of several plates of different density or cell structure. For example, a plate for the middle region 7 and 5 is formed each time a plate for the edge regions 8, 9.

For the manufacture of such a sound-damping element 1, as shown in figure 1, it is now possible to work according to the following method:

Plates are made of a soft foam material with uniform density substantially throughout the entire thickness, in which, for example, a support body 10 consisting of a wire mesh or wire grid is foamed. Optionally, however, it is also possible to use plates 5, 6 cut from a block of soft plastic foam, between which an adhesive layer 11 and the support body 10 are arranged. At the same time, in a heated press for the production of the sound-proofing element, the covering layers 2 and 3 are laid in with the interposition of an adhesive layer 12, 13.

Subsequently, the press is heated in the region of the cover layers 2, 3 to a temperature of about 100 to 150 ° C and a suitable surface load is applied to the sound-proofing element 1 laid in the mold. Due to the load distributed over the surface under simultaneous temperature action, in the edge regions 8, 9 the cell structure breaks and a thickness of the core layer 4 is reduced due to this compaction. The breakdown of the cells due to the simultaneous action of pressure and temperature also results in a greater density and a higher specific weight of the foam in the edge regions. By a suitable choice of the temperature and the pressure load, the thickness of the edge areas or the change in density and the specific weight can easily be adapted to different applications.

The adhesive used for the adhesive layer 11, 12 and 13 is preferably water-repellent but air-permeable, so that the air can enter the areas of the plates 5, 6 and the core layer 4 unhindered unhindered.

However, it is also possible for moisture insulation and for gluing the individual layers 5 of the sandwich-like sound-damping element 1 together, instead of using adhesive films, for example polyethylene films, for the adhesive layers. When the sound-proofing element 1 is heated, this foil melts and acts as a water-repellent protective layer and at the same time as an adhesive layer for connecting the individual layers of the sound-proofing element 1.

Due to the use of open-pore foams with high elastic properties in the area of the core layer 4 and in the area of the covering layer 3, the sound-damping element 1 according to the invention can be mounted directly on a part 19 to be protected against the noise directed thereto.

It is advantageous here if the connection between the connecting means and the holder 17 to the carrying body 10 is effected by means of elastic intermediate elements 20, so that a vibration and thus sound transmission from the sound-damping element to the part 19 is reliably avoided.

Figure 2 shows part of the core layer 4. As can be seen, this core layer is composed of closed cells 25 and the interconnected open cells 26, which are formed by the net structure.

In order now to allow an air passage through the adhesive layer between the covering layer 3 and the core layer 4, a glue 27 is used which has a consistency which does not allow the spanning of larger cavities, so that the glue 27 only against the net structure of the open cells 26 abut against the closed cells 25, respectively. This ensures that air passages remain open in the connection surfaces between the cover layer 3 and the core layer 4, through which the air can enter or exit the core layer 4, respectively.

Figure 3 shows the arrangement 8602132 * m - 18 - of sound-damping elements 1 according to the invention on the inside of a hood 28, which is composed of hood parts 29 and 30, which for instance consist of glass-fiber reinforced plastic. Inside the hood 28, for example, a diesel engine 31 is provided, which emits air and contact sound, which are symbolically indicated by arrows 32 and 33, in all directions. The soundproofing elements 1 are connected to the hood parts 29 and 30 by the support body 10 and the connecting means 18.

As can be seen from Figure 3, the deformability of the individual plates and elements of the sound-damping element according to the invention make it possible to adapt them to arbitrary spatial deformations of the hood parts 29 and 30 -15, respectively, as shown in particular. with the sound damping element 1 associated with the hood part 29.

Obviously, according to the invention, instead of the MDI-driven plastic foams, TTI-driven plastic foams can also be used.

The choice of the specific weights of the plastic foam in the edge or middle regions can also be varied in a suitable manner, in order to achieve better damping behavior, for example for more energy-rich energy vibrations.

Furthermore, it is also possible to use a cotton fiber fleece or a synthetic fiber fleece for the mat 15. If an adhesive is used for the adhesive layer, care must be taken to ensure that it retains its adhesive effect even after heating to about 150 ° C or liquefies in this temperature range, for example during the temperature and pressure loading of the sound-deadening element at the same time being able to carry out the adhesive bond of the individual plates or the layers, respectively, to ensure that a permanent adhesive bond is obtained in the sandwich. The heated presses known from the prior art can be used for the pressure and temperature loading of the sound-damping element during manufacture and deformation, respectively.

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Figure 4 shows a sound-damping element 101, which consists of a covering layer 102 and a covering layer 103, and a core layer 104 arranged between these. The core layer 104 comprises, as schematically indicated, a middle region 105 and two edge regions 106 107. This core layer 104 may consist of one piece, of a plastic foam with predominantly open cells, in particular a plastic foam plate. However, it is also possible to merge the edge areas and the middle areas from your own plates.

As indicated by the schematic representation from the cutting plane in the region of the head side, the edge regions 106, 107 and the middle region 105 have a different density of the open-cell plastic foam. These edge regions 106, 107 are formed by open-cell plastic foam under pressure, ie mechanically and respectively or thermally compacted. Preferably, in this embodiment plastic foam with the same properties is used for the middle region 105 as well as for the edge regions 106, 107. When a one-piece core layer 104 is used, then the edge regions 106, 107 are obtained by compaction applied in the surface region under simultaneous heat supply. As Figure 4 further shows, the regions 108 have a greater thickness 109 than the regions 110, which have only a thickness 111. As expressed by the schematic, the core layer 104 in the region 110 is denser and accordingly has a higher density and thus a higher specific gravity. This is achieved in that the open-cell structure is more compacted by the higher pressure in the regions 110 under the simultaneous thermal load. It is also possible to expose the areas to be densified more strongly to a higher temperature, in order to facilitate deformation or permanent deformation of the open-cell plastic structure, respectively.

Preferably, an element having the same surface area in the region 110 of less thickness 111 and in the region 108 of greater thickness 109 has the same weight. The cover layers 102 and 103 can be formed by pressure-deformable films or reticulated materials of fabric, fiber or other artificial or natural materials. Preferably, it is possible to form one of the two cover layers 102, 103 from a cardboard saturated with unsaturated polyester resin. In one embodiment, in which the one cover layer 102 is formed by a cardboard saturated with unsaturated polyester resin, this cover layer 102 is applied, for example in a vehicle, near a body 112, for example the sheet metal parts of the cabin space. The fixing between the sound-damping element 101 and the covering layer 102 and the body 112 can be effected by gluing or by suitable fastening means of plastic or metal. The opposite cover layer 103 may be formed by carpets or leather or the like formed of artificial or natural fibers. If the cover layers 102 and 103 are joined together directly during the manufacture of the sound-damping element 101 according to the invention, for example by using melting foils 113 - as schematically indicated in the lower part of Figure 4, care must be taken, that the cover layers 102 and 103 permit suitable elastic deformation and temperature loading.

With the sound-damping element 101 shown, for example, the soft foam material or plastic foam with open-cell structure used can have a specific weight of about 9 to 10 kg / m and this material is used, for example, in the peripheral areas 106, 107, in particular for example also in the region 110, in which it only has a thickness 111, compacted to a specific gravity of about 40 to 30 kg / m. This leads to the fact that the denser structure of the soft foam in the region 110 creates a greater stability of the sandwich element with respect to the surface regions 108, and thus in those regions in which a thickness 109 of the thickness of the fabric is determined by the constructional requirements. sound-damping element 101 is not possible, nevertheless sufficient strength against damage is ensured in normal operation. In spite of all this, however, with such a sound dampening element it is achieved that it has a high elasticity and that good damping properties are achieved in crashing persons, since the more solid and strong compacted areas 110 are directly in the areas 108 with a greater elasticity and thus in the whole also the more compacted area 110 is more elastically damped than with a foam filling with plastic materials with predominantly closed cells.

Due to a suitable force and temperature action during the manufacture of the sound-damping elements according to the invention, the density variation in the edge regions 106 and 107 can also decrease progressively in the direction of the middle region 105.

Figure 5 shows a cross-section through a sound-damping element 114, which can for instance be used as a covering element in a vehicle, for covering the interior space. As can be seen from this top view of the sound-damping element 114, it has differently thick and differently deformed surface areas 115, 116, 117 and 118. A core layer 119 and an associated cover layer 120 must allow sufficient deformation to allow the profiling of material without damage to the material. enable the soundproofing element. For this purpose it is possible, in the very highly compacted and weakened areas 117/118 and in order to enable sufficient strength for the provision of connecting devices, to support members 121 at least in separate areas in a favorable manner in the core layer 119. which, after shaping the core layer 119, keep and stabilize these planar regions 117, 118 in the intended shape. The carrier body 121 may be grids or films, which are soaked with different resins or other adhesives, or grids and grids formed of metal or the like, which harden after the deformation and temperature treatment. keep the sound dampening element 114 in the desired shape.

Of course, it is also possible with this sound-damping element 114 to apply a further covering layer on the side of the core layer 119 opposite the covering layer 120.

SS02132 * - 22 -

Figure 6 shows a part of the core layer 122 and a cover layer 120 in highly simplified form and perspective. By this representation, the mode of operation of the mechanical and thermal compaction of the edge regions 123 relative to a center region 124 must be graphically explained. As can be seen, in the edge region 123 facing a surface 125 of the core layer 122, the open cells 126, which are formed by a spatial lattice of plastic with a number of connecting walls 127, are compressed by the mechanical and thermal compaction, whereby the approximately spherical cells and spherically constructed connecting surfaces 127 are compressed and broken and preferably partially enclosed closed cells 128 with respect to the center region 124, in which they are approximately spherical, assume an elliptical shape. Owing to the pressure and temperature, the open cells 1262 are compressed and deformed on these forming bonding walls 127, thereby increasing both strength and density and specific gravity in edge region 123.

When this densification takes place over a surface, it decreases in the direction from the middle region 124, depending on the selected processing criteria, linearly or progressively, to the middle region 124, in which the original unaltered cell structure remains.

The solution according to the invention is thereby distinguished from those sound-damping elements, in which a foaming with skin formation is used, in order to achieve a hard surface with a soft core, in that the densification of the edge areas by arbitrary limits is controlled by the temperature and pressure applied. is. With reference to figure 6, only the rationale of the solution according to the invention, the properties of soft foam sheets by changing a suitable compaction, is schematically shown for a better understanding. Accordingly, arbitrary deviations can be present both with regard to the strongly exaggerated large ratios and also the course of the connecting walls of the open-cell structure, and the solution according to the invention is in no way limited to the embodiment shown 8602132-23.

With regard to the coatings used, the application of the method and the device according to the invention is also not limited. For example, fabrics, natural or artificial leather, nonwoven fabrics, nets or the like can be used as cover layers, whereby both natural and artificial fibers can be used. Preferably, these coatings can also be impregnated with moisture-resistant or flame-resistant materials. or 10 are covered with it. It is advantageous here if these additional or introduced materials only harden in the desired shape during the pressure and temperature treatment after the deformation of the soundproofing elements has been deformed. This reliably prevents the spring-back of the sound-damping elements in their initial position.

In the same manner, any desired material can also be used for the support body 121. For example, it is possible to use suitable nonwoven fabrics, fiber nets or the like of metal, plastic or natural fiber and wires, preferably carbon fiber wires. It is furthermore advantageous if this support body is provided with a layer of unsaturated polyester resin and the support body thus retains in this deformed position during the temperature and / or pressure load after deformation.

It is of course also possible to place the support body between two suitably shaped foam material plates and to bond them with one or two adhesive layers, for instance melting foils, to these plastic layers.

The sound-absorbing elements according to the invention are preferably used in motor vehicles, in particular for lining passenger compartments or driver's cabs in trucks. However, these can of course also be used for insulation of flats or for the sound insulation of other machines.

8602132

Claims (34)

Self-supporting, sandwich-like soundproofing element with two spaced-apart, different cover layers and a core layer consisting of plastic foam disposed therebetween, characterized in that the core layer (104, 119, 122) is oriented in the direction of the two cover layers (102, 103, 120) is of increasing density and consists of a plastic with predominantly open cells (126). Soundproofing element according to claim 1, characterized in that the compacted cell structure is formed in the edge regions (106, 107, 123) facing the two cover layers (102, 103, 120) from a mechanically and thermally or thermally compacted open-cell plastic foam. Soundproofing element according to one of claims 1 or. 2, characterized in that the specific gravity of the open-cell plastic foam of the core layer (104, 119, 122) in the middle region (105) and the edge region (106, 107, 123) is different, however preferably the edge region has a density two to five times as high as the middle area. Soundproofing element according to any one of claims 1 to 3, characterized in that the middle region (105) is formed of a soft foam material, in particular with a specific weight of about 9 to 10 kg / m. Soundproofing element according to any one of claims 1 to 4, characterized in that the core layer (104, 119, 122) consists of a predominantly open-cell soft foam material, in particular an MDI-driven or cross-linked polyether or polyester plastic foam. . Soundproofing element according to one of Claims 1 to 5, characterized in that the core layer (4) has a densified cell structure in the edge areas (8, 9) facing the two cover layers (2, 3). proportion of closed cells (25) then comprises the cell structure in a middle region (7) between these edge regions (8, 9). Soundproofing element according to any one of claims 1 to 6, characterized in that the soft 8602132 - 25 foam is formed by a / in particular MDI-driven or cross-linked polyether or polyester plastic foam, and the core layer (4 ) is preferably formed by a part of a soft foam block. Soundproofing element according to one of Claims 1 to 7, characterized in that the core layer (4) consisting of central and peripheral regions (7; 8.9) is formed as one piece. Sound-proofing element according to one of Claims 1 to 8, characterized in that the cover layer (2, 3) is moisture-repellent, in particular as a polyethylene film, and the open cells (26) of the edge region (8, 9) of the core layer (4) are connected to the ambient air through openings in the cover layer (2, 3) or the adhesive layer (12, 13) or the polyethylene film. Sound-proofing element according to one of claims 1 to 9, characterized in that the moisture-repellent cover layer (2, 3) or the polyethylene film on the side facing away from the core layer (4) for a fiber mat (14) with fibers or wires (21), which are resistant to high temperatures, are provided, which fiber-mesh has openings (16) distributed over the surface and in particular is designed as a net. Sound-proofing element according to any one of claims 1 to 10, characterized in that the fibers or wires (21) are formed by glass fibers and, respectively, or carbon fibers and, respectively, or metal fibers. Soundproofing element according to one of Claims 1 to 11, characterized in that on the surface of the other covering layer (3) facing away from the fiber mat (14), a mat (15) of water-repellent non-woven fabric and of foam material, respectively , for example, of an open-cell soft foam, the thickness (22, 23) of which is part of the thickness (24) of the core layer (4). Soundproofing element according to one of Claims 1 to 12, characterized in that the individual regions of the core layer (4) mutually and respectively or the covering layer (2, 3) with the core layer (4) and 6602132 - respectively. 26 - either the covering layer (2, 3) with the mat (15) applied for it and, respectively, or fiber mat (14) by an adhesive layer (11, 12, 13), in particular with the cell frame of the core layer (4) are joined and the adhesive layer (11, 12, 13) is air-permeable, the adhesive layer (12, 13) preferably forming the cover layer (2, 3). Sound-proofing element according to one of Claims 1 to 13, characterized in that the adhesive layer (11, 12, 13) is formed by the polyethylene foil which is designed as a melting foil. Sound-proofing element according to one of Claims 1 to 14, characterized in that in the core layer (4) and in the region between the core layer (4) and the fiber mat (14) or the mat (15), respectively, elastically deformable support body (10) is provided, which is designed to be air-permeable and / or sound-permeable in the direction of the cover layers (2, 3). Soundproofing element according to any one of claims 1 to 15, characterized in that the core layer (104, 119, 122) is associated with an elastic, particularly deformable support body (121) and thus transmits force and whether or not as to form is appropriately connected. Soundproofing element according to one of Claims 1 to 16, characterized in that the core layer (4) is two-piece and each consists of a plate (5, 6), between which the elastically deformable support body (10) is applied, in particular glued. Sound-proofing element according to one of claims 1 to 17, characterized in that the support body (10) and either the adhesive layer (11, 12, 13) and the cover layer (2, 3) and whether the fiber mat (14) and whether the mat (15) are water vapor permeable, respectively. Soundproofing element according to any one of claims 1 to 18, characterized in that the fiber mat (14) is arranged near a sound source (20) and protects the mat arranged on the opposite top side to protect the 8802132 - 27 - part (19), wherein the sound-damping element (1) is arranged between the sound source (20) and a housing surrounding it, for example the hood (28) and is connected to it by a supporting body (10). Soundproofing element according to any one of claims 1 to 19, characterized in that a thickness of the middle region (7) differs in proportion to the thickness of the two edge regions (8, 9) of the core layer (4), preferably, however, three times the size of the edge-10 regions (8, 9). Sound-proofing element according to any one of claims 1 to 20, characterized in that the specific weight of the plastic foam of the core layer (4) differs in the middle region (7) and the edge regions (8, 9), preferably however, the edge region (8, 9) has twice the specific weight as the middle region (7). Soundproofing element according to any one of claims 1 to 21, characterized in that the number of open cells (26) in the central region (7) and in the peripheral region (8, 9) of the core layer (4) is different. and in particular from the edge area (8, 9) increases towards the middle area (7), Sound-proofing element according to any one of claims 1 to 22, characterized in that a covering layer (102) facing the one edge region of the core layer (104, 119, 122) is formed by a material or foil-deformable material and the covering layer (102, 103, 120) facing the other edge region is formed by a non-woven material and, respectively, a cardboard impregnated with unsaturated polyester resin, and is preferably deformed and / or curable under temperature and / or pressure. Soundproofing element according to any one of claims 1 to 23, characterized in that an adhesive layer is preferably arranged between the cover layers (102, 103, 120) and the core layer (104, 119, 122). by a polyethylene film designed as a melting film (113) and the core layer (104, 119, 122) and, respectively, or the adhesive layer 3602132 -9 Sr- - 28 - and, respectively, or the carrier body (121) and, or one or both, the cover layers ( 102, 103, 120) are air-permeable, in particular moisture-resistant. Soundproofing element according to any one of claims 1 to 24, characterized in that at least one of the cover layers (102, 103, 120) and or at least one of the two edge regions (106, 107, 123) are provided are of a moisture-repellent extra impregnation. Soundproofing element according to any one of claims 1 to 25, characterized in that the core layer (104, 119, 122) comprises surface areas distributed differently, highly compacted (108, 110; 115-118), wherein preferably the weight of the core layer 15 (104, 119, 122) based on the same surface area and the respective thickness in the differently highly compacted surface areas (108, 123, 115-118) are approximately the same. 27. A method for manufacturing such sound-damping elements as claimed in any one of claims 1 to 26, wherein a plastic core layer with different cover layers is joined in a force-transmitting manner, characterized in that a block of soft foam foam is foamed and placed in plates is distributed, after which heat is supplied to the facing surfaces of one or two directly adjacent plates, in particular at the same time, and they are loaded with a compressive force directed towards the middle layer and the edge areas of the plate are plastically deformed . 28. A method according to claim 27, characterized in that for the heat supply between the facing surfaces of two plates an adhesive layer or an adhesive foil and optionally a support body, in particular a wire grid or the like, is introduced. 29. Method according to claim 27, characterized in that, by the heat effect, coatings are simultaneously applied on the surfaces of the core facing away from each other. ..... .... X. - 29 - are applied and bonded to this force-transmitting material, one coating being formed by a fiber mat and the other coating by a mat. A method according to any one of claims 5 to 27, characterized in that the core layer and the supporting body are spatially deformed during the heat and force action. 31. A method according to any one of claims 27 or 30, characterized in that heat-sealable plastic films are placed on the surfaces for heating and densifying the edge areas of the plate and by the heat and force action with the edge areas. of the core layer. 32. A method according to any one of claims 15 to 31, characterized in that the magnitude and duration of the force action as well as the magnitude and duration of the temperature effect can be changed depending on the desired damping properties of the plate, it is the same in both peripheral areas. 33. A method according to any one of claims 27 to 32, characterized in that the fiber mat associated with one covering layer and the mat belonging to the other covering layer are applied simultaneously and are force-transmitting with the facing surfaces of the covering layers. connected. 34. A method of manufacturing sound-damping elements according to any one of claims 1 to 26, characterized in that at least a part of the core layer of constant thickness is preferably joint with at least one cover layer with an adhesive layer in between, in the. In particular, a polyethylene melting film is molded and compacted to different thicknesses under the simultaneous action of pressure and temperature in different surface areas, the individual layers being simultaneously interconnected and, respectively, or cured, after which, preferably in the same operation sound-absorbing element is cut to the desired peripheral shape. 8602132