DE4131394A1 - Low weight laminar sound absorbing sheet - has skin(s) of porous fibre materials with glass cloth and honeycomb type core layer with infill and with walls at right angles to skin - Google Patents

Abstract

A sound-absorbing material is made up of at least two layers; at least one is a porous fibre mat and is glued to at least one other constituent but in such a way as to maintain the porosity to air; a core layer has walls running at right angles (or inclined) to the first-mentioned layer so as to form a number of cells open at their ends. These cells are pref. filled with glass-reinforced polyurethane foam, or glass-filled thermosetting resin, or fibres and/or expanded glass; the core walls are pref. made of cardboard, pressed/bonded fibreboard or flax; the surface layer pref. contains a glass cloth and thermosetting binder. ADVANTAGE - The prod. has a high sound absorbency, a low wt., and can be tailored to customer's requirements. It is environmentally satisfactory.

Description

The invention relates to a Schalldämmaterial which as Ver Bund is composed of at least two layers.

In the case of airborne sound, essentially of such sound insulation one should distinguish between materials directly generated airborne sound, by volume change forces, ie pressure changes occur and is emitted directly, and indirectly generated airborne sound due to the vibration excitation and sound emission of an oscillatory mecha niche system. While for damping the directly generated Airborne sound only the reduction of a spread of the once airborne sound can be sought,  exist with indirectly produced airborne sound the possibilities the excitation force, the input impedance, the transmission impedance and to influence the degree of emission. In addition to changes the technology to the occurrence of sound from the outset more or less, primary and secondary measure took the sound emission reduction met, with the secondary measures the full or partial encapsulation of machinery or installations and the use of silencers in general be is known. Primary measures of sound emission relate on the operation in which the sound is generated, the Excitation of vibrations, their transmission and transmission as well as the radiation properties of a system. By the Ver Use of sound insulation material of the type mentioned is mainly the transmission impedance increased, that is, it will be the losses on the transmission path within a Construction enlarged. Here are insulating materials in the so-called sandwich construction particularly proven. It is to make sure that when insulated on metal sheet structures is to be, the Schalldämmaterial with the metal sheet in tight But it must be avoided that new ones should be avoided Sound transmission bridges are generated. Furthermore, that is Wall thickness ratio of metal sheet to the Schalldämmaterial to be at least 1: 5. The increase of the loss factor a factor of 10 leads to a reduction in the sound level of about 10 dB (A).

The advantages of primary measures exist in particular in the less vibration excitation of the systems, which may be also leads to a longer life of moving parts.

Nowadays there is a need for reasons of the possible low environmental impact and resources too spare, for example, non-load-bearing body panels as possible to keep thin. On the one hand there is the problem of sound On the other hand, the reinforcement of this thin  Parts.

From DE-A 29 09 802 is a layer material for sound insulation, in which the insulating properties on one Fiber layer based. These are, however, high fiber layer thickness required, the basis weight by the use of Bitumen as a binding agent is unacceptable for many purposes is increased.

Further, DE-A 36 43 481 describes an acoustic panel, in which the absorber surface formed by Helmholtz resonators becomes. Such an absorber material has only a small Strength up, and is also sensitive to moisture.

Finally, from DE-A 30 22 461 a Entdröhnungsbelag Track for body panels with a multilayer structure be known. This also has a high basis weight. you is only designed to train loadable and does not wear at the same time tig to stiffen. This is no weight reduction of Complete system possible.

It is the object of the present invention, a sound insulation material that realizes good noise reduction can be, while also reducing weight of the entire system of sound insulation material and compo insulation should be possible to continue to customer-specific Requirements regarding the multi-functionality of sound material to be fully met, and that is to be fende Schalldämmaterial should be environmentally friendly.

This object is achieved by a Schalldämmaterial of the beginning mentioned genus with the characteristics of the plate of patent claim 1 solved. Advantageous embodiments are the subject the dependent claims. A procedure for Production of Schalldämmaterials invention is  Subject of claim 13 and the back referenced him sub-claims. Uses of Schalldämmaterials are in to claims 16 and 17.

According to the invention, at least one of the layers consists of one air-permeable nonwoven fabric, wherein the layer with at least a further component of the composite is glued so that the air permeability of the nonwoven fabric substantially he holds, as a further layer is a core layer with in the substantially vertical, possibly slightly inclined, to the Layer of air-permeable non-woven fabric running walls, which in their entirety a plurality at least at one End face open cavities form, provided. By the appro The selection of material components can produce a high level of sound insulating ability while increasing the strength at For example, a sheet metal construction can be achieved. It can with the Schalldämmaterial invention reductions the sheet metal wall thickness can be realized by up to 10%, which is a Significant weight saving means. The sound dams This is because of the semipolar effective layer permeable nonwoven fabric, while the structure of the Core layer mainly contributes to stability, but also can have semipolar areas.

According to a preferred embodiment of the invention are the Cavities provided with a sound-absorbing filling. These Core layer filling further contributes to improved sound insulation. In the frequency range smaller than 800 Hz values become achieved for the absorption coefficient of more than 0.3; at higher frequencies from 800 Hz to 2500 Hz increase the absorption tion coefficient even disproportionately to the thickness of the sound and reaches values of 0.6 and above.

Basically, the soundproofing filling for any suitable material, with regard to the to be solved  Task regarding the environmental compatibility or resource Scho However, recycled materials should be used. For example the filling can at least partially made of glass fiber reinforced Polyurethane foam, preferably from shredded glass fiber ver Reinforced polyurethane foam, glass fiber reinforced thermoset plastic, textile fibers and / or expanded glass or the like consist. Even a mixture of these substances is conceivable, though for reasons of later disposal and the necessary Material separation a uniform material will be preferred.

Also as a material for the walls of the core layer recyclates are possible, for example, porous cardboard. The walls may also be formed from pressed and bonded fiber composite material. Natural fiber fleeces, preferably flax fiber fleeces having a weight per unit area of less than 200 g / m ² , have proven particularly useful.

It is conceivable that the cavities of the core layer of ge corrugated endless strips are formed, with parallel guided Strips are glued to corresponding shaft bellies. A excellent stability is achieved, however, if the core layer from a variety glued together hollow cylinder-like Single body is constructed. These can polygo in cross section nal, the hexagonal cross section for reasons of "Parquetability", which means maximum adhesive surfaces, special is preferred. Also for a triangular, square or rectangular cross section would be given this advantage. It However, the hollow cylinder can also be circular in cross section be, which optionally manufacturing advantages with can bring. Also, the core layer can be open from one side nen hat be constructed.

Although it is sufficient, the core layer with only one side Cover a layer of air-permeable nonwoven fabric and the open area of the core layer directly on the  to apply to be insulated or stiffened metal sheet is it prefers on both sides of the core layer at least one layer from an air-permeable non-woven fabric vorzuse as a cover layer hen. This simplifies automatic production.

It can also be the layer of a permeable nonwoven fabric continue to contain a glass fabric layer and with a duro be pre-consolidated plastic binder. This can be the deck layer or can provide the outer layers as semi-finished be presented.

A method for producing a Schalldämmateriales, esp especially in continuous operation, is characterized in that little At least one of the top layer is prepared, which is little at least one layer of at least one air-permeable Nonwoven fabric consists, the top layer konti with a core layer is pressed and the composite at high temperatures and deformed under pressure and solidified.

If the core layer to be filled with insulating material, be preferably prepared two outer layers, with a first the outer layers pressed continuously with the core layer and substantially simultaneously or slightly in time trailing, the hollow cylinder of the core layer with a sound be provided insulating insulation. It is time-lagging then the second cover layer with the core layer continuously pressed.

In most cases, the sound-absorbing filling is in the hollow cylinders are injected.

The sound insulation material is particularly suitable as a molded part, in particular for the interior lining of motor vehicles and the like, but also for the sound insulation on thin sheets the body. Thus, the Schalldämmaterial to  Absorption of airborne sound emissions and soundproofing of Driving machines, such as electric motors or combustion engines or from other sources of excitation in the automotive body sector be used. The training as Mehrfunktionsverklei Training is conceivable, especially in connection with a car mobile body, for example, for receiving intake air filter systems or as a receiving channel for the wiring or Piping in the automotive industry. It can be used as spacer material between the bonnet and the metal skin to the drive unit be used. As Entdröhnungsmaterial it can be synonymous be used wisely if it is not on the gain function arrives.

The field of application for the new sound insulation material is not up the automotive industry is limited. It can always be used there be, where it comes to the shielding of noise sources, where the entire machine and plant construction, also the aviation, is affected. Examples are the use in pneumatic and mechanical conveyor systems, to reduce noise on Ventilato compressors, turbines, pumps, centrifuges, grinders, granu lators, control valves or the like, even on torches, such as Gas flare systems, and process ovens. Likewise Installations that produce sound waves as intended are effective insulated against the outside environment, for example Vibra tion conveyors and vibrators. Also hydro drives, Rohrleitun conditions with high flow rates and recooling systems can sound with the material according to the present invention be insulated. It can be used as a reflection silencer in the serve a wide range of applications, including verbs acoustics in closed rooms and finally as personal soundproofing agent at the workplace.

In the following, the invention is intended merely by way of example The accompanying drawings are explained in more detail. Showing:  

Fig. 1 is a schematic representation of he inventive Schalldämmaterials, partially torn open;

Fig. 2 is a perspective view of a hollow body for the core layer;

Fig. 3 shows a second embodiment of a Hohlkör pers in the form of a cap, because of the choice of material also referred to as Flachsütchen net;

Figure 4 is a representation of the overall construction of the Schalldämmaterials invention.

Fig. 5 is a detail of a cover layer and

Fig. 6 is a schematic representation for Realisie tion of the method for the production of the sound insulation material according to the invention.

Fig. 1 shows a schematic representation of the Schalldämmaterials according to the present invention in plate form. Between an upper cover layer 1 and a lower cover layer 3 is a core layer 2 , which is composed of a plurality of hollow cylinders 4 , which have a hexagonal cross-section. The emitted sound power is absorbed by the semi-polar, ie partially permeable layer of the cover layers 1 , 3 , broken behind the semi-polar layer as a sound wave, diffused emitted and absorbed by a located in the core layer 2 soundproofing filling. This filling is unevenly excited to vibrate, whereby the sound energy is fully degraded by conversion into heat energy. The degree of radiation obtained is a Mate rialkonstante and depends on the nature of the filling material. Furthermore, partially occurring pressure changes due to volume changes in the cavities of the hollow cylinder 4 lead to the total absorption of sound waves of a certain, Chen in wesentli specified by the dimensions of the hollow cylinder 4 frequency range. A reflection of the occurred sound wave is thus largely excluded. The best Absorptionswer te have been achieved with shredded glass fiber reinforced Polyorethanschaum as soundproofing filling. This is due to the bizarrely shaped particles with an irregular surface structure.

Fig. 2 shows a perspective view of the hollow cylinder 4 , wherein it is clear that a honeycomb structure of the core layer can be achieved by planar arrangement of a lot of such a hollow cylinder. In this case, a good mechanical stability of the Schalldämmaterials is achieved even at a relatively low-height of the hollow cylinder 4 ge.

Another example of a structure for the core layer is shown in FIG. 3, where the cavities are formed by a flat cap 5 .

example 1

A constructed by means of hollow cylinders 4 of Fig. 2 core layer with the above-described filling of shredded glass fiber reinforced polyurethane foam is closed on both sides by a cover layer. This consists in each case of the Schich tenfolge Synthesefaservlies-Glasgewebematte-Synthesefaservlies. The connection to the core layer is via a duroplasti rule binder. A Schalldämmaterial with a layer thickness of about 6 mm and a basis weight of 1750 g / m ² can be achieved when materials of the following type are selected (in the sequence of the layer structure):

Basis weight (g / m²) Synthetic fiber web 20 Woven glass mat 120 Synthetic fiber web 60 Thermosetting binder 300 core layer 250 + Filling 500 Thermosetting binder 300 Synthetic fiber web 60 Woven glass mat 120 Synthetic fiber web 20

Example 2

The structure of the outer layers is selected as in Example 1, but the core layer has flax cap instead of the hollow cylinder, as a filling is a mixture of shredded glass fiber reinforced polyurethane foam with thermosetting binder, expanded glass beads and fibrillated synthetic fibers and natural fibers used, wherein the mixture is formed, that a basis weight of 700 g / m ^{2 can be set} for the filling. A sound insulation material with a layer thickness of approx. 9 mm and a surface weight of 1900 g / m ² can be produced if the materials are selected as follows:

Basis weight (g / m²) Synthetic fiber web 20 Woven glass mat 120 Synthetic fiber web 60 Thermosetting binder 300 core layer 300 + Filling 700 Thermosetting binder 300 Synthetic fiber web 60 Woven glass mat 100 Synthetic fiber web 20

Fig. 4 is a schematic illustration of the overall construction of a Schalldämmaterials according to the present invention from this representation is particularly evident, the honeycomb structure of the core layer 2 can be seen which is formed of a plurality of hollow cylinders 4 with a hexagonal cross-section. These individual bodies are bonded together at their interfaces, at least some of the faces 40 show semi-polar behavior. The hollow cylinder 4 are provided with a filling 41 , in this example, only half-filled hollow cylinder are Darge presents. The fibrous surface of the cover layer 3 , in the direction of the core layer 2 , is merely indicated here. A cutout 30 is shown enlarged in FIG .

Fig. 5 shows the layer structure of the cover layer 3 of Fig. 4 in detail. At the interface with the core layer, first glass fabric 31 is provided, followed by a layer synthesis fiber fleece 32 , a Duroplastbinder 33 membrane 34 is attached thereto.

In Fig. 6, the realization of a method for producing the Schalldämmaterials invention is schematically represents. The starting point is preconsolidated cover layers, which are prepared in the form of endless strips or strip sections. One of the cover layers 1 serves as a carrier material onto which the core layer 2 is applied so that the open ends of the cavities to an atomizing device 7, which injects under defined adjustable conditions a pre-wetted with binder filling material 41 into the cavities of the core layer. 2 The further cover layer 3 is supplied and placed on the open cavities, whereupon the overall arrangement is fed to a pair of rollers 60 , 61 of two counter-rotating rollers whose closest distance is slightly greater than the desired layer thickness of the sound insulation material. Between these rollers 60 , 61 we closed the composite and precompressed over a preselected contact pressure or pre-consolidated. The filling 41 , which here completely occupies the cavities of the core layer 2 , is thus between the cover layers 1 , 3 eingeschlos sen. Depending on the application, further processing takes place. It can be in a second pair of rollers 62 , 63 , the rollers wiede rum in opposite directions to each other and a distance aufwei sen, which substantially corresponds to the thickness of the finished material, under elevated temperature, usually at temperatures above 100 ° C, in the desired final shape. However, it is also possible for the semi-finished slabs to be dimensionally cut in a further operation and then brought into the desired shape by pressing.

The fillings used for the core layer can be used without white teres from collected residual materials of series production manufactured by interior trim parts of the automotive industry become. It is also conceivable shredded waste of recycled old automobiles to use. Become textile fibers used, you can also these from residual and / or  Winning old materials. The blown glass for the filling is off Glass can be produced.

Areas of application are the automobile in particular sidewall covers, trunk and hatrack covers, the engine Room encapsulation and other acoustically problematic Be rich in body outer skin, in the passenger compartment can Floor covers, door panels, the headliner, the hutab and the tonneau cover, the A, B, C pillar cover gene and side panels with the material of the invention be effectively soundproofed.

The in the above description, in the drawing and in The claims disclosed features of the invention can both individually or in any combination for the Verwirkli tion of the invention in its various embodiments be essential.  

LIST OF REFERENCE NUMBERS

1 cover layer
2 core layer
3 topcoat
4 hollow cylinders
5 flat shells
6 pressing device
7 spraying device
30 section of the cover layer 3
31 glass fabric (with binder)
32 synthetic fiber fleece
33 Duroplast binder
34 membrane film
40 semipolar wall
41 soundproof filling
60, 61 first pair of rollers
62, 63 second pair of rollers

Claims (17)

1. sound insulation material, which is constructed as a composite of at least two layers, characterized in that at least one of the layers ( 1 , 3 ) consists of an air-permeable nonwoven fabric, wherein the layer ( 1 , 3 ) so bonded to at least one further component of the composite is that the air permeability of the nonwoven fabric is substantially maintained, and that as another layer, a core layer ( 2 ) with substantially vertical, optionally slightly inclined to the layer ( 1 , 3 ) of air-permeable nonwoven ver running walls, which in their entirety form a plurality at least on one end side of open cavities ( 4 ), is seen before. 2. sound insulation material according to claim 1, characterized in that the cavities ( 4 ) are provided with a sound-absorbing filling. 3. sound insulation material according to claim 1 or 2, characterized marked records that the sound-insulating filling at least partially made of glass fiber reinforced polyurethane foam, preferably made of shredded glass fiber reinforced polyurethane foam, from glass fiber reinforced thermosetting plastics made of textile fibers and / or made of expanded glass or the like. 4. sound insulation material according to one of claims 1 to 3, characterized in that the walls of the core layers ( 2 ) are formed of porous cardboard. 5. sound insulation material according to one of claims 1 to 3, characterized in that the walls of the core layer ( 2 ) are formed from pressed and glued fiber composite material. 6. sound insulation material according to one of claims 1 to 3, characterized in that the walls of the core layer ( 2 ) of natural fiber webs, preferably made of flax fiber webs with a basis weight less than 200 g / m ^{2 are} formed. 7. sound insulation material according to any one of claims 1 to 6, characterized in that the core layer ( 2 ) consists of a plurality of numbers bonded together hollow cylinder-like single body ( 4 ) is constructed. 8. sound insulation material according to one of claims 1 to 7, characterized in that the cavities or hollow cylinders ( 4 ) are formed with polygonal, preferably hexagonal cross-section. 9. sound insulation material according to one of claims 1 to 7, characterized in that the cavities or hollow cylinder ( 4 ) are circular in cross section. 10. sound insulation material according to any one of claims 1 to 8, characterized in that on both sides of the core layer ( 2 ) at least one layer ( 1 , 3 ) is provided from an air-permeable nonwoven fabric as a cover layer. 11. Sound insulation material according to one of claims 1 to 10, characterized in that the layer ( 1 , 3 ) further contains a glass fabric layer. 12. sound insulation material according to any one of claims 1 to 11, characterized in that the layer ( 1 , 3 ) is preconsolidated with a duro plastic binder. 13. A method for producing a Schalldämmaterials according to one of claims 1 to 12 in continuous operation, characterized in that

• at least one covering layer is prepared, which consists of at least one layer of an air-permeable non-woven fabric,
• - The cover layer is pressed continuously with a core layer and
• - The composite is deformed at high temperatures and under pressure and permanently solidified.

14. The method according to claim 13, characterized in that

• - be prepared two layers,
• one of the cover layers is pressed continuously with the core layer,
• - At the same time or slightly later in time, the cavities or hollow cylinder of the core layer are provided with a sound-insulating filling, and
• - Trailing in time, the second outer layer is pressed continuously with the core layer.

15. The method according to claim 13 or 14, characterized records that the soundproofing filling in the cavities or Hollow cylinder is injected. 16. Use of a sound insulation material according to one of the Proverbs 1 to 12, as a molded part, in particular for the Innenver clothing of motor vehicles and the like. 17. Use of a Schalldämmaterials according to one of Claims 1 to 12 for the sound insulation on thin sheets or like.