EP1590176A1

EP1590176A1 - Method and device for soundproofing oscillatory components, such as sheet metal, and coating therefor

Info

Publication number: EP1590176A1
Application number: EP03785713A
Authority: EP
Inventors: Karlheinz Bildner; Ralf Dopheide; Christoph Freist; Zdislaw Kornacki; Marcus Simon; Josef Polak; Bernhard Koch
Original assignee: AKsys GmbH
Current assignee: AKsys GmbH
Priority date: 2003-02-21
Filing date: 2003-12-02
Publication date: 2005-11-02
Also published as: AU2003294769A1; WO2004073984A1

Abstract

The invention relates to a method and a device for soundproofing oscillatory components such as sheet metal, by connecting a soundproofing coating (5) to the component (1), at least one intermediate layer (2) being applied between the soundproofing coating (5) and the oscillatory component (1). Said intermediate layer (2) is advantageously an especially elastomer adhesive layer which is applied, in a free-flowing state, for example by means of coextrusion, before the soundproofing coating (5) or at the same time. In this way, a material used for adhesion can be used as the intermediate layer and a material for acoustics can be used as the soundproofing material. The invention also relates to a corresponding coating and a device which automatically applies the coating, especially to sheet metal.

Description

Method and device for the anti-drumming of vibratable components, such as metal sheets, and coating therefor

The present invention relates to a method and a device for the anti-vibration of vibratable components such as sheets according to the preambles of patent claims 1 and 17. Furthermore, the invention relates to a corresponding anti-drumming coating according to the preamble of patent claim 8.

Processes, devices and coatings of this type for the deadening of, for example, automotive sheet metal are known, foils made of viscose-elastic substances being firmly connected to the component to be damped in order to damp structure-borne noise. When swinging along, the damping layer is deformed by strain. Due to different E-modules and layer thicknesses, there is a complex bending stiffness of the composite system, for which an overall loss factor can be calculated depending on the frequency. The frequency to be “deadened” is often the natural frequency of the component to be deadened, which is caused by an external source, the total loss factor being able to be improved primarily by a high loss factor of the damping layer or a high modulus of elasticity of the damping layer.

Anti-drumming compounds based on bitumen, epoxy resin compounds or rubber compounds are known as anti-drumming coatings to be applied to the vibratable component. They are usually applied by spraying or extrusion in the flowable state. at Epoxy resin compositions and other thermally or chemically curing compositions, such as materials containing multifunctional acrylates, have been shown to slightly deform the sheet metal that supports them during curing. Particularly in the case of high-gloss surfaces, as are common in today's motor vehicle bodies, this means that the area of the anti-drumming covering, for example on the inside of a door panel, is reflected on the outside by light reflections, which is not acceptable in today's motor vehicles.

The problem of the deformation of thin sheets by a polymerisation-curing (anti-drumming) coating is explained, for example, in US Pat. No. 5,712,317. In this publication, the problem is solved by deformable microspheres in the hardening mass, which is, however, quite expensive and can undesirably change the acoustic effectiveness of such masses.

As a rule, anti-drumming coatings based on bitumen or rubber do not exert as high forces as thermally or chemically hardening compounds, so that deformations or marks can hardly occur on the component that supports them, such as thin sheet metal. However, it has been shown that at particularly low temperatures the adhesion of this anti-drift coating to the sheet metal is no longer sufficient.

The publication EP 0 199 372 B1 describes anti-drumming compounds which can be applied by spraying and which crosslink at temperatures of about 140 ° C. and thus become sufficiently hard.

In addition to the deformation of sheet metal and the adhesion to the sheet metal, further stress requirements must be met, in particular in the automotive industry, which in addition to the acoustic test also subjects the coated components to mechanical tests, such as a cold impact test, a mandrel bend, an aging test or a climate change test. It should also be possible to use it in body-in-white on oiled sheets and there should be KTL compatibility. The invention is therefore based on the object of specifying a method and a device for the deadening of vibratable components, so that a composite material produced in this way not only meets the acoustic requirements, but also marks on the metal sheets in the area of the anti-noise coating and detachment of the anti-noise coating in particular low temperatures can be avoided. The de-drone coating should also reinforce the vibratable component if possible and meet the other mechanical load requirements. Furthermore, an anti-drumming coating serving these purposes is to be developed.

The present objects are achieved by the characterizing features of independent claims 1, 8 and 17. Further advantageous embodiments of the invention result from the subclaims.

According to the invention, at least one intermediate layer, which consists in particular of an elastomeric material, is applied between the dehumidifier coating and the vibratable component.

The incorporation of an intermediate layer between the anti-drone coating and the vibratable component results in a functional separation of the anti-drone coating. By using an elastomer adhesion promoter layer as the intermediate layer, which can be applied to the component in the flowable state, as a preferred embodiment of the invention, the damping layer (as part of the anti-drumming coating) adheres well to the component. Such a material exhibits its elastomeric properties after the phase change through solidification, gelation or poly- or copolymerization. These properties are effective in a temperature range from -40 ° C to 80 ° C.

The anti-drone coating, which can be produced very inexpensively, prevents different expansions of the component or the anti-drone coating from causing stresses and thus deformation. of the component and thus, for example, to markings on the sheet metal of an automobile body or to a loosening of the anti-drumming coating from the sheet metal at low temperatures. Likewise, thanks to the invention, a polyreaction-hardening material can be used as the anti-drift coating, which deforms to such an extent when it hardens that the component, such as a thin sheet metal, would deform without the intermediate layer. In the case of bituminous compositions or rubber compositions, thanks to the invention there is no longer any need to consider the cold adhesion of the compositions, because the intermediate layer, as an adhesion promoter layer, holds the anti-drift coating reliably on the component.

In any case, the intermediate layer ensures that relative movements between the dehumidifying coating and the component in the intermediate layer are absorbed, so that no shear forces arise which could lead to a loosening of the dehumidifying coating or a sheet metal deformation. This also applies to the coating of a vibratable wire or tube.

The at least one anti-drone coating is also advantageously applied in the flowable state after or simultaneously with the at least one intermediate layer. This can be done, for example, by injection molding or by means of coextrusion. In this case, sprayable or extrudable materials can be used as the anti-drift coating or as an intermediate layer, which materials are applied manually or (semi) automatically to corresponding components of the automobile, for example after the galvanizing of an automobile body, using a coextrusion nozzle.

If you apply de-stick coatings in the form of foils to a sheet, you need an elastic intermediate layer, because only through such an intermediate layer can the foils be attached to the sheet. So far, it has always been considered an advantage when applying drone coatings in the flowable state by extrusion or spraying that such an intermediate could avoid shifting. However, the present invention shows that such an intermediate layer also has advantages in the case of de-drone coatings applied in the flowable state, which justify its additional expenditure.

A damping layer, a stiffening layer or a combination of damping layer and stiffening layer can be used as the anti-drift coating. Depending on the type of application, location and / or temperature, different anti-drift coatings can be used, which consist of one or a combination of damping or stiffening materials. For example, both the damping layer and the stiffening layer or the intermediate layer can consist of a viscous plastic which hardens through polymerization, copolymerization, polycondensation or crosslinking (crosslinking). The intermediate layer should be compatible with the layer of the dehumidifying coating facing the intermediate layer, since this is permanently bonded to the component by means of the intermediate layer. “Compatibility” is understood below to mean those plastics or plastic / metal combinations which can be adhesively bonded to one another, for example polymerizing or crosslinking.

The intermediate layer advantageously consists of a plastic material which obtains its properties by thermal or chemical hardening, in particular by solidification, by polyreaction or by gelling. According to a particular embodiment of the invention, the intermediate layer consists of an elastomeric material adhering to metal, which compensates for tensions between the anti-drift coating and the component, in particular also at temperatures below approximately -5 ° C. and above approximately 35 ° C.

According to a further advantageous embodiment of the present invention, a corrosion layer can be introduced between the intermediate layer and the dehumidifier coating, which protects a corrosive component against corrosion, provided that this task does not already exist is perceived by the damping layer, the stiffening layer and / or the intermediate layer. For example, the intermediate layer can be provided with a powdery, electrically conductive material which is electrically conductively connected to the component made of metal, so that the electrically conductive intermediate layer can be connected to a galvanically coupled electron sink (sacrificial anode), which can be replaced if necessary, and that protects the component from corrosion.

According to a further advantageous embodiment of the present invention, the dehumidifier coating consists of a styrene damping layer which is applied to a thin sheet by means of an intermediate layer made of EVA. According to a further embodiment, the anti-drift coating consists of a stiffening layer made of an epoxy resin, which is applied to the sheet metal by means of an intermediate layer made of butyl. Furthermore, it has been shown that a de-drone coating consisting of a bitumen damping layer and an epoxy resin stiffening layer achieves particularly great advantages, since the vibratable component is steamed and stiffened. The intermediate layer advantageously consists of butyl.

Conventional adhesives and other elastic materials can also be used for the intermediate layer, for example highly elastic thermoplastic and thermo-crosslinkable butyl compositions and acrylates or soft PVC coatings, such as seam seals and underbody protection compositions, which are generally used in the automotive industry. Two- and multi-component systems such as acrylates with epoxy resins, bitumen with rubbers containing double bonds, etc. can also be used as an intermediate layer.

Furthermore, it has been shown that as an anti-drumming coating a cross-hardenable mass has particular advantages, since it can also be applied to very thin-walled sheets by means of the elastic intermediate layer. As a drone coating For example, an epoxy resin composition can be used, which also improves the acoustic properties of the anti-drumming coating compared to a coating without an intermediate layer.

In the selection of conventional bitumen-based mixtures, an inexpensive bitumen composition can also be used for the dehumidification coating, since less consideration must be given to the cold adhesion of the bitumen composition due to the elastic intermediate layer. Just as with the epoxy resin compound, the intermediate layer also improves the acoustic effectiveness of the entire anti-drumming coating.

The same applies to the use of a rubber-based mass as a damping layer.

For the deadening of sheet metal in vehicle construction, it has proven to be optimal if the anti-drift coating has a layer thickness of about 0.5 to 10 mm, in particular 1 to 4 mm, and the intermediate layer has a layer thickness of 0.1 to 1.2 mm. If a de-drone coating consisting of a stiffening layer and a damping layer is used, the stiffening layer advantageously has a layer thickness of approximately 0.1 to 2.5 mm and the damping layer a layer thickness of approximately 0.3 to 8 mm. The total thickness of the anti-drone coating, consisting of the intermediate layer and the anti-drone coating, is advantageously about 1 to 3 mm. The basis weight of such a coating is generally between about 2 kg / m ² and 4 kg / m ² .

If the intermediate layer is “compatible” with the layer of the dehumidifying coating facing the intermediate layer, this can be applied together with the intermediate layer by means of spraying or (co-) extrusion in one operation or only two operations. Such application by means of coextrusion is both with synthetic resin compositions and with Bitumen or rubber mass possible, the latter materials can also be fed as granules via an extruder.

The device according to the invention for the anti-drumming of vibratable components advantageously has an extrusion nozzle, by means of which the plastic anti-drift coating can be applied to the component. In addition to the dehumidification coating, the extrusion die can also apply the at least one intermediate layer on the vibratable component.

If a coextrusion die is used, the dehumidifier coating can be applied simultaneously with the intermediate layer, the coextrusion die being advantageously fed at the same time by at least two metering devices which meter, mix and melt the materials which can be used for the corresponding layers, the materials just before or shortly after leaving the nozzle mouth, and the intermediate layer provided with the anti-drift coating is then applied to the component.

According to a special embodiment of the present invention, the coextrusion nozzle is simultaneously fed by at least two extruders which meter and melt the thermoplastic materials which can be used for the corresponding layers, plastic granules advantageously being automatically fed from central storage containers to the extruders, so that they are continuously filled with thermoplastic material be supplied.

Some preferred exemplary embodiments of the present invention are explained in more detail with reference to the accompanying drawings. Show:

FIG. 1 shows a layer structure according to the invention with a double-layer de-stick coating, FIG. 2 shows a layer structure according to the invention with a single-layer dehumidifying coating,

FIG. 3 shows a layer structure according to the invention with a different single-layer dehumidifying coating,

FIG. 4 shows a diagram which shows the acoustic loss factor of a sheet coated by the method according to the invention as a function of the temperature,

FIG. 5 shows a diagram corresponding to FIG. 4 for the embodiment of the invention according to FIG. 2,

6 shows a diagram corresponding to FIG. 4 for the embodiment of the invention according to FIG. 3,

FIG. 7 shows a diagram corresponding to FIG. 4 for the embodiment of the invention according to FIG. 1,

Figure 8 is a schematic representation of an inventive device for applying the anti-drumming coating.

Figures 1 to 3 show three advantageous embodiments of the invention with different anti-drift coatings 5, which are applied to a component 1, for example a thin sheet. Between the anti-drone coating 5 and the component 1 there is an intermediate layer 2 made of, in particular, elastomeric material, which at least partially mechanically and acoustically decouples the anti-drone coating 5 from the component 1.

FIG. 1 shows a de-drone coating 5 consisting of a damping layer 3 and a stiffening layer 4.

FIG. 2 shows a de-drone coating 5 consisting only of a damping layer 3, while FIG. 3 shows a de-drone coating 5 consisting of a stiffening layer 4 and the intermediate layer 2, in which the stiffening layer 4 is connected to the component 1 by the considerably thicker intermediate layer 2. The intermediate layer 2 also exerts an adhesive effect, that is to say a connecting effect.

In this respect, FIG. 3 shows a special embodiment of the present invention, in which the intermediate layer 2 performs adhesion-promoting tasks and, together with the stiffening layer 4, also performs acoustically decoupling or steaming tasks. The component 1 is connected to the stiffening layer 4 in such a way that the vibrability of the component 1 is greatly reduced by choosing a natural frequency for the stiffening layer 4 that differs from the natural frequency of the component 1.

Suitable materials for the individual layers are the thermoplastic, reactive or materials which chemically crosslink by two components, as shown in Table 1.

Table 1 Sprayable multilayer compositions and corresponding material combinations

The coextrusion process is the preferred application technique for sprayable multi-layer materials. According to the present - ii -

According to the invention, the different layers of the anti-drumming coating are applied according to a preferred embodiment by means of a coextrusion process. This method is suitable for the fully automatic application of the viscous, multi-layer acoustic compound to vehicles or corresponding vehicle components. This achieves high-quality vehicle damping that also meets the mechanical load requirements.

To carry out this process, a coextrusion die is used, which can be constructed both on the principle of the “inner mixture” and on the principle of the “outer mixture”. In the case of internal mixing, the material layers are brought together with a sheathing adapter, so that air trapping between the material layers is minimized. In the case of external mixing, the material layers are joined together in the nozzle, also without noticeable air pockets. The corresponding process parameters such as material quantity, mixing ratio and output quantity then decide on the determination of the mixing process to be used.

Eight preferred materials for the intermediate layer, damping layer and stiffening layer and associated application techniques according to the present invention are shown in Table 2:

Table 2 Examples of "compatible" materials for the individual layers of the dehumidifier coating and the intermediate layer including the associated application technique

FIG. 4 shows, as a curve marked with triangles, the anti-drumming effect of a coating with an epoxy resin composition as material for the damping layer, which is on a thin layer elastomeric intermediate layer made of PVC was applied. The weight per unit area of the epoxy resin composition was 3.0 kg / m ² , and that of the intermediate layer was 0.3 kg / m ² . The curve marked with diamonds shows the setpoints required by the automotive industry. It can be seen that the curve for the coating according to the invention lies at about -20 ° C. and + 60 ° C. on the target curve, but from approximately 0 ° C. to 60 ° C. it runs above the target curve and has a range of approximately between 20 ° C and 40 ° C a clear distance from the target curve. The range between approximately 10 ° C. and 40 ° C. is the temperature range for sheets facing the vehicle interior, for example door sheets or roof sheets. The acoustics in a vehicle can thus be significantly improved by the invention.

The curve marked with squares (without intermediate layer) runs significantly below the target curve up to over 30 ° C and only surpasses it at around 40 ° C with a peak. The anti-drone coating without an intermediate layer is therefore only better at higher temperatures than the coating according to the invention when using a single-layer epoxy resin composition as a damping layer 3. It can therefore be used, for example, for the engine compartment, but is rather unsuitable for sheet metal for the vehicle interior.

FIG. 5 shows the anti-noise effect of a coating similar to FIG. 4 with an intermediate layer made of EVA and a damping layer made of styrene. FIGS. 4 and 5 correspond to a layer structure according to FIG. 2, EVA or butyl being particularly preferably used as the intermediate layer and bitumen, styrene or an epoxy resin composition being particularly preferably used as the damping layer. This layer structure has a thickness of 1.7 mm with a weight per unit area of 2.4 kg / m ² .

FIG. 6 relates to a structure according to FIG. 3 with a relatively “thick” intermediate layer 2 and stiffening layer 4. From FIG compared to the previous damping curves there is a considerably improved dehumidification effect of the stiffening layer 4 applied to the component 1 by means of the intermediate layer 2. The loss factor lies over the entire temperature range from approximately -20 ° C. to +60 ° C. above the setpoint curve from FIG. 4, here as the intermediate layer 2 butyl and as a stiffening layer 4 with advantage epoxy resin is used. Other advantageous materials for the intermediate layer 2 are bitumen or rubber and acrylate for the stiffening layer 4. The total thickness of this layer structure is 2.0 mm, while the weight per unit area was 3.1 kg / m ² .

FIG. 7 shows an improved dehumidifying effect of a layer structure according to FIG. 1, in particular in the upper temperature profile from approximately 10 ° C. compared to FIG. Particularly preferred materials are 2 butyl for the intermediate layer, 3 bitumen for the damping layer and 4 epoxy resin composition for the stiffening layer. The total layer thickness of this structure is 1.6 mm with a basis weight of 2.58 kg / m ² . It can be seen from FIG. 7 that a three-layer structure of the anti-drumming coating consisting of intermediate layer 2, damping layer 3 and stiffening layer 4 has about the same good acoustic damping properties as a structure according to FIG. 3 with a 40% reduced thickness and approximately 17% reduced basis weight and with approximately the same basis weight and about the same layer thickness as in a layer structure according to FIG. 2, acoustic damping values improved considerably.

FIG. 8 schematically shows a device according to the invention for applying the de-drone coating 5 with intermediate layer 2 to a component 1. For fully automatic use, a coextrusion nozzle 6 is advantageously installed on a robot (not shown) and with flexible material supply lines to metering systems such as two extruders 7a and 7b connected. The dosing systems must be controllable separately, both in print mode and also in volume mode to achieve a defined material layer structure in the coextrusion nozzle. The corresponding materials used for the coating can be stored in granular form in a central material container (not shown) and can be supplied to the individual take-off points of the steaming agent application, that is to say the extruders 7a and 7b in the production line, via supply lines, for example via compressed air and corresponding valves. In the case of thermoplastic materials, these are melted for application by means of the extruders and brought to pump viscosity and fed to the metering system with the coextrusion nozzle 6 as a pasty acoustic mass. The individual layers are advantageously brought together only shortly before or shortly after the nozzle mouth 8 in order to achieve a defined material confluence and a defined layer thickness of the anti-drumming coating.

During the time, for example, when a vehicle is being moved from one station to the next station, the robot travels with the extruders 7a, 7b under the granule feed line and new granulate is picked up, for example, via a funnel system. This process saves the process of changing the barrel at each dam application station and drastically reduces the maintenance costs of the system, since the heating hoses that connect the robots and the supply system can be dispensed with.

Claims

claims

1. A method for the deadening of vibratable components such as sheet metal, by connecting a flowable dehumidifying coating (5) to the component (1), characterized in that between the dehumidifying coating (5) and the vibratable

Component (1) at least one intermediate layer (2) is applied.

2. The method according to claim 1, characterized in that the at least one intermediate layer (2) is an in particular elastomer adhesive layer which is applied in the flowable state.

3. The method according to claim 1 or 2, characterized in that the at least one drone coating (5) is applied in the flowable state after or together with the at least one intermediate layer (2).

4. The method according to claim 2 or 3, characterized in that the anti-drone coating (5) and / or the intermediate layer (2) are applied by spraying on the component (1).

5. The method according to claim 2 or 3, characterized in that the dehumidifier coating (5) and / or the intermediate layer (2) are applied to the component (1) by coextrusion.

6. The method according to any one of the preceding claims, characterized in that a damping layer (3) and / or a stiffening layer (4) is used as the anti-drone coating (5).

7. The method according to any one of the preceding claims, characterized in that a viscous plastic is used as the damping layer (3) and / or as a stiffening layer (4) and / or as an intermediate layer (2), which by polymerization, copolymerization, polycondensation or crosslinking ( Crosslinking) hardens.

8.Anti-drone coating for removing drones from vibratable components such as sheet metal, with an anti-drone coating (5) which is connected to the component (1), characterized in that there is at least one intermediate layer between the anti-drone coating (5) and the vibratable component (1). 2) is located.

9. Coating according to claim 8, characterized in that the intermediate layer (2) consists of a material which can optionally be applied at the same time as the de-drone coating (5) in the flowable state and is thus compatible with the de-drone coating (5) and the component (1) that it binds permanently with them.

10. Coating according to one of claims 8 or 9, characterized in that the intermediate layer (2) consists of a plastic material which ode maintains its properties by thermal and / or chemical hardening, in particular by solidification, polyreaction.

11. Coating according to one of claims 8 to 10, characterized in that the intermediate layer (2) consists of an elastomeric material adhering to metal, the tensions between the anti-drift coating (5) and the component (1) in particular also at temperatures below about -5 ° C and above about 35 ° C compensates.

12. Coating according to one of claims 8 to 11, characterized in that the anti-drift coating (5) consists of a damping layer (3) or a stiffening layer (4) or a damping layer (3) and stiffening layer (4).

13. Coating according to claim 12, characterized in that the anti-drone coating (5) consists of a damping layer (3) made of styrene, while the intermediate layer (2) consists of EVA.

14. Coating according to claim 12, characterized in that the anti-drone coating (5) consists of a stiffening layer (4) made of an epoxy resin, while the intermediate layer (2) consists of butyl.

15. Coating according to claim 12, characterized in that the anti-drone coating (5) consists of a damping layer (3) made of bitumen and a stiffening layer (4) made of an epoxy resin, while the intermediate layer (2) consists of butyl.

16. Coating according to one of claims 8 to 15, characterized in that that the anti-drone coating (5) has a layer thickness of approximately 0.5 to 10 mm, in particular 1.0 to 4.0 mm, and the intermediate layer (2) has a layer thickness of approximately 0.1 to 1.2 mm.

17. Device for the deadening of vibratable components such as sheet metal, an extrusion nozzle applying a dehumidifying coating (5) made of plastic to the component (1), characterized in that at least one intermediate layer (2) on the vibratable component (1) is applied.

18. The apparatus according to claim 17, characterized in that a coextrusion nozzle (6) applies the dehumidifier coating (5) together with the intermediate layer (2), the coextrusion nozzle (6) being fed simultaneously by at least two metering devices which are used for the corresponding layers Dose, mix and / or melt usable materials so that the materials are only connected to each other shortly before or after leaving the nozzle mouth (8), and then the intermediate layer (2) provided with the anti-drift coating (5) on the component (1) is applicable.

19. The device according to claim 18, characterized in that the coextrusion nozzle (6) is fed simultaneously by at least two extruders (7a, 7b) which meter and melt the thermoplastic materials which can be used for the corresponding layers, and in that the extruders (7a, 7b ) can be supplied with plastic granulate from central storage containers.