DE19720537A1 - Thermal insulation for sound absorbing elements etc. in cars - Google Patents

Abstract

Covering for mounting parts, body parts etc. of motor vehicles, heat-radiating machines and equipment, especially sound-absorbing elements, to protect them from excessive heating from mechanisms, catalyst parts etc., comprising the following layers (starting from the heat source): (a) textile sheet made of inorganic glass, mineral silicate, ceramic and/or carbon fibres, (b) mineral wool insulating layer over part or all of the surface where the thermal stress is particularly high, (c) optionally perforated metal foil over part or all of the surface as for (b), (d) non-woven textile fabric bonded with thermosetting resin and optionally (e) a non-woven fabric sheath to protect from mechanical damage. Also claimed is a process for the production of this covering by pressing and bonding (a) and (d) together by the action of the thermosetting binder.

Description

The invention relates to a lining of built-in parts, body parts or the like of automobiles, especially sound-absorbing elements to protect against excessive heat from machine parts, exhaust gas stungen catalyst parts or the like, comprising an optionally perforated metal foil.

In the engine compartment of modern vehicles, both for cars and commercial vehicles are increasingly sound insulation parts in the form of absorbers Reduction of engine noise used. These mainly as molded parts The absorbers have an influence on the outside and inside noise of the driver witness. For example in the area of exhaust manifolds or exhaust gas recirculation systems these parts are subject to higher heat loads. Mostly turned on today set molded parts made of nonwoven fabrics (e.g. cotton) or PU foam typically have heat resistance up to approx. 160 ° C.  

At higher heat loads, these molded parts are on the heat source le facing surface partially or completely with aluminum foils as Heat reflector laminated to protect the fiber nonwovens behind. At even higher thermal loads, a difference is made between aluminum foil and servliesstoff another layer of mineral wool (for example basalt stone wool le) inserted to additionally increase the thermal insulation.

The use of the heat reflectors in the form of metal foils has acoustic gra disadvantages because they are impermeable to air and therefore the sound absorber destruction of nonwoven fabrics.

It is known to install components in particularly heat-stressed areas Protect lamination of aluminum foils. Such built-in parts are on DE-U-87 00 919 known. However, this has the disadvantage that the sound-absorbing effect of the one under the aluminum lining Installation part is lost because the sound does not penetrate the aluminum foil can.

US-A-2 887 173 relates to a sound absorber. A heat reflection for thermal insulation is not possible because the body this sound absorbers made of aluminum - column 2, lines 66 to 68 - and thus one Represents thermal bridge. The holes provided there are not used Sound radiation, but should with the mate present in the absorber rialien form acoustic resonators.

The corrugation of the muffler known from DE-U-19 83 950 serves its purpose Adaptation to walls with convex and concave formation. The usage of synthetic resin as the material for the top layer prevents heat reflection de effect.  

Finally, US-A-4 335 797 and US-A-4 122 908 show a noise attenuation fender machine cladding, the access of outside air for cooling purposes allowed, therefore also not used for heat reflection.

EP 0 309 776 B1 describes cladding of built-in parts, body parts or the like of automobiles, especially sound absorbing Elements to protect against excessive heat from machine parts, Exhaust ducts, catalyst parts or the like, consisting of an aluminum Foil (2), which is characterized in that the aluminum foil (2) perforates and is profiled.

Starting from this prior art, the object of the invention based on an improved paneling of the type described above create, which on the one hand remains effective as a reflector for heat radiation, on the other hand is at least partially permeable to sound waves, so that sound absorbers underneath in the form of thermoset bound Textile fiber nonwovens remain acoustically effective.

The solution to the problem according to the invention consists in cladding built-in parts, body parts or the like of automobiles, heat-radiating machines and units, in particular sound-absorbing elements for protection against excessive heat loads by machine guides, catalyst parts or the like, comprising an optionally perforated metal foil with a layer structure in order from the heat source:

• a) textile structure made of inorganic glass fiber, mineral silicate fiber, Ceramic fiber and / or carbon fiber,
• b) Increase the partial or full-surface mineral wool insulation layer in the area thermal load,
• c) partial or full-surface metal foil in the area of increased heat Belela  stung,
• d) thermosetting bonded textile fiber fleece and optionally
• e) cover fleece to protect against mechanical damage.

The invention is therefore based on a compilation of materials that eliminates the acoustic disadvantages present in the prior art will. Here, on the side of the molded part facing the heat source, For example, it is made of cotton fiber fleece, first a high temperature resistant thin cover fleece also as surface protection from an inorganic applied fiber material. A layer is partially behind it temperature-resistant, non-combustible fibers, for example made of basalt rock wool, on which a metal foil is applied. Because the protective layer can absorb high-temperature-resistant fibers more acoustically, the acoustic disadvantages of foil lamination are eliminated. The middle in the metal foil arranged in the system can also be perforated so that the the thermoplastic plastic fleece behind it is also acoustically can be effective. With this material structure, you can achieve heat distortion resistance temperatures up to 400 ° C on the surface of the molded part.

Ins are suitable as a textile structure for protecting the mineral wool insulation layer special high temperature resistant fiber structures based on inorganic Fibers. Nonwovens are particularly preferred for the purposes of the present invention, Woven or knitted fabrics of the fibers mentioned.

In the context of the present invention, textile glass fibers include fibers and Sides from glassy melts of sodium, potassium and other silicates too understand that after the nozzle sieve (silk), rod sieve (silk and fiber) or produced by the jet glass process (fibers). Is characteristic the incombustibility of the glass fibers, their high heat resistance, large brittleness durability and low abrasion resistance. You have a very  high tensile strength, low elasticity and are rot-resistant.

Mineral silicate fibers are mineral fibers that melt from natural ones Silicates or of mixtures with silicates, for example calcium, Aluminum, magnesium silicates can be obtained. The mineral silicate fibers are very fine and smooth and have a round cross section and an amorphous Structure. The thermal conductivity is low, they are non-flammable and against everyone normal chemical effects in the same way as glass resistant. Since the fibers cannot be spun alone, they are already in the State of the art in mat forms or similar forms, mainly for Insulation purposes used at high temperatures.

Ceramic fibers in the sense of the present invention are inorganic chemical fibers silicon and rayon, or with some oxides for example of iron, aluminum, magnesium and / or calcium oxide.

The ceramic fibers are usually made of quartz fibers, ceramic fibers of the type A, G and V divided.

Quartz fibers have a smooth surface, glass-like structures and one round cross section. Chemically, quartz fibers are resistant to all usual chemicals. They are used for filter material at high temperatures and in aggressive media, as insulation material in rockets, jet aircraft engines, nuclear power plants, blast furnaces and the like. Type A ceramic fibers have properties that correspond approximately to those of quartz fibers. Also the properties of type G ceramic fibers correspond approximately to those of Quartz fibers, they are resistant up to 1000 ° C and have good electrical insulation properties at high temperatures and are the only flexible material with electrical insulation properties in textile form.  

With type V ceramic fibers, depending on the degree of combustion, the viscous carrier mass the properties vary greatly. You will be in Form of threads, fabrics, knitted fabrics, nonwovens for insulation at high Temperatures, for heat shields in space and on blast furnaces, in jet flight engines, rockets and the like are used.

Carbon fibers in the sense of the present invention are inorganic Fibers and silks by means of structural transformation by means of organic fibers Pyrolysis can be obtained. Depending on the proportion of carbon and that in pyrolysis applied temperature one divides the carbon fibers into partially carboni based carbon fibers, carbonized carbon fibers and graphite fibers. Carbon fibers often become plastic in the form of fibers and threads reinforcement, as electrical insulation material, for reinforcing metals, building materials, Materials used for space flight, rockets, etc.

In addition to the above-mentioned inorganic fibers, they are in principle also metallic cal fibers can be used in the textile structures. The disadvantage of metallic However, fibers consist in the high thermal conductivity, so that these in the textile structures can only be used in minor quantities.

For the purposes of the present invention, the textiles particularly preferably comprise Formation of layer a) carbon fibers.

The layer thickness of the respective layers can be varied within a wide range, adapted to the requirements. For the purposes of the present invention, it is particularly preferred that the layer thickness of the textile structures is 0.5 to 1.5 mm. It is also particularly preferred if the textile structure has a weight per unit area of 50 to 200 g / m ² . The textile structure serves in particular as mechanical protection for the mineral wool insulation layer, which is known to have low strength. The oleophobic and hydrophobic character of the fibers protects the other layers in the cladding.

In the sense of the present invention, it is particularly preferred that the mineral wool insulation layer, which is partially or completely covered in the area of increased thermal load, is produced on the basis of basalt stone wool. The mineral wool insulation layer is introduced according to the invention in the areas in which particularly good thermal insulation is required. It can be assumed that usually no full coverage of the textile structure with the mineral wool insulation layer is required. The textile structure made of inorganic fibers is therefore partially provided with the mineral wool insulation layer only in areas of increased heat load. The layer thickness of the mineral wool insulation layer makes up an essential part of the total layer thickness of the laminates according to the invention. The layer thickness of the mineral wool insulation layer is preferably 5 to 20 mm and in particular has a basis weight of 400 to 2000 g / m ² .

Also the metal foil, which is between the mineral wool insulation layer and the thermosetting bonded textile fiber fleece is partially or fully introduced into the system in areas of increased heat load. More common the size and position of the metal foil is therefore in the same way chooses how the mineral wool insulation layer, however it is in the sense of the present Invention also possible that the metal foil has a larger or smaller upper surface than the macroscopic surface of the mineral wool insulation layer. Aluminum foil is a particularly preferred material for the metal foil which is commercially available in various strengths. At in the state of Known absorbers are usually a layer thickness of the aluminum film of 250 µm or more selected. Accordingly, it is also in the sense of the present invention possible aluminum foil with layer thicknesses in the range from 50 to 500 µm. Particularly preferred in the sense of the present  However, aluminum foils with layer thicknesses in the range of 50 are invented used up to 100 µm. These small layer thicknesses can be used because the other components of the laminate according to the invention also static function take over.

Due to the perforation of the aluminum foil, if present, one becomes maintain the effect of aluminum foil as a heat reflector, others but in this area, permeability to sound waves is achieved, so that is on the side of the aluminum foil facing away from the sound source Chen thermoset bonded textile fiber nonwovens remain acoustically effective.

Textile fiber fleeces are a frequently used construction in the automotive sector material with a wide range of properties. For example, phenolic resin Bound textile fiber fleece for a long time, among other things because of its good Damping properties as a material for load-bearing and clad parts (pure or as a composite) in the automotive industry in car and truck construction used.

Phenolic resin-bonded textile fiber fleece is commercially available in bulk densities of 50 to 1000 kg / cm ^{3 and} in thicknesses of 5 to 30 mm. It can be described as a so-called pore composite, consisting of three phases (cotton, hardened phenolic resin and air) - a construction material whose property profile can be modified within wide limits. Cotton is in the form of fibers, phenolic resin is in punctiform form, also in the form of a matrix on the surface of the mesh.

The acoustics and strength of the Composite are particularly controlled. Particularly preferred materia Lines for the production of the nonwoven are glass fiber reinforced or glass grids reinforced fiber materials, in particular textile fleeces containing binders, preferably those that consist of a cotton blend. This  Nonwovens are pressed to the desired temperature at elevated temperatures Brought firmness.

The special properties and performance of the latter Product group can be explained by the chemical and morphological structure the cotton, as well as the thermoset character of the hardened phenolic resins, which are usually used as binders for cotton blended fabrics will. Other influencing factors are the deformability, the ironability of the Cotton, the statistical bond point frequency and also the laminate and / or Cladding effect of the fibers adhering along and thus also condensed Binder molecules.

The cotton survives the manufacturing process practically without change their physicochemical characteristics. It gives the product special quality features such as sound absorption capacity, good mechanical Strength values, impact strength and splinter resistance in the cold.

Particularly preferred binders for the nonwovens are selected from Phenol-formaldehyde resins, epoxy resins, polyester resins, polyamide resins, Polypropylene, polyethylene and / or ethyl vinyl acetate copolymers. Phenolic resins have the typical thermosetting properties after hardening, which affect the Finished product transferred. The textile fiber fleece is made from the tear cotton and the powdery phenolic resin is usually produced in a dry way. The Curing takes place either in the heating duct or via the unhardened semi-work as an intermediate stage in the press. For the parts that are in the vehicle compartment Ver selected textile is used.

Textile fiber fleeces in the sense of the present invention preferably contain Natural fibers, especially cotton, flax, jute, linen, but also art fibers such as polybutylene terephthalate, polyethylene terephthalate, nylon 6, nylon 66,  Nylon 12, viscose or rayon as textile fiber, possibly in addition to the usual ones Binders.

The type and amount of the binders to be used is essentially determined by determines the application of the textile fiber fleece. So in general the use of 5 to 50 wt .-%, in particular 20 to 40 wt .-% of the bandage means, based on the textile fiber fleece preferred.

According to the invention, it is particularly preferred to use textile fiber nonwovens with a layer thickness in the range from 5 to 40 mm. In the same way, it is particularly preferred if the textile fiber nonwovens have a basis weight of 400 to 2000 g / m ² .

If necessary, the layer structure comprises layer e), which is a cover fleece to protect mechanical damage. This also serves as a cover fleece, for example a thin needle fleece or spin fleece, to protect the tool from dirt. The layer thickness should preferably be 30 to 80 g / m ² .

The total layer thickness in the area in which four are superimposed Layers are present, should preferably be 10 to 40 mm.

The moldings according to the invention are preferably used in the field the front wall of engine compartments or in the area of the transmission tunnel of power vehicles.

The molded parts according to the invention are, as usual, by hot forming Process manufactured so that tools known per se in the prior art and production facilities for a given material changeover can be used. Particularly preferred in the sense of the present  Invention, the panels are made by making the textile Form with the thermosetting bonded textile fiber fleece under the influence of thermosetting binder pressed and glued. A bond only occurs here the areas in contact. The surface of the metal foil should preferably do not have an adhesive layer in which there is a risk of constipation perforation is to be feared.

Claims (14)

1. Cladding of built-in parts, body parts or the like of automobiles, heat-radiating machines and units, in particular of sound-absorbing elements for protection against excessive heat loads by machine guides, catalytic converter parts or the like, comprising an optionally perforated metal foil with a layer structure in order from the heat source:

• a) textile structure made of inorganic glass fiber, mineral silicate fiber, ceramic fiber and / or carbon fiber,
• b) partial or full-surface mineral wool insulation layer in the area of increased heat load,
• c) partial or full-area metal foil in the area of increased heat stress,
• d) thermosetting bonded textile fiber fleece and optionally
• e) cover fleece to protect against mechanical damage.

2. Panel according to claim 1, characterized in that the textile structures includes nonwovens, woven or knitted fabrics. 3. Panel according to claim 1 or 2, characterized in that the textile structure comprises carbon fibers. 4. Cladding according to one or more of claims 1 to 3, characterized in that the layer thickness of the textile structure is 0.5 to 1.5 mm and in particular has a weight per unit area of 50 to 200 g / m ² . 5. Cladding according to claim 1, characterized in that the Mineral wool insulation layer includes basalt stone wool.   6. Cladding according to one or more of claims 1 to 5, characterized in that the layer thickness of the mineral wool insulation layer is 5 to 20 mm and in particular has a weight per unit area of 400 g to 2000 g / m ² . 7. Panel according to one or more of claims 1 to 6, there characterized in that the metal foil consists of aluminum. 8. Panel according to one or more of claims 1 to 7, there characterized in that the layer thickness of the aluminum foil is 50 to 500 µm, is in particular 50 to 100 microns. 9. Panel according to one or more of claims 1 to 8, there characterized in that the textile fiber fleece comprises cotton fibers. 10. Panel according to one or more of claims 1 to 9, there characterized in that the textile fiber fleece binder made of phenolic Formaldehyde resins, epoxy resins, polyester resins, polyamide resins, poly propylene, polyethylene and / or ethyl-vinyl acetate copolymers. 11. Cladding according to one or more of claims 1 to 10, characterized in that the layer thickness of the textile fiber fleece is 5 to 40 mm and in particular has a weight per unit area of 400 to 2000 g / m ² . 12. Cladding according to one or more of claims 1 to 11, characterized in that the cover fleece comprises a needle punch or spin fleece, in particular with a basis weight of 30 to 80 g / m ² . 13. Cladding according to one or more of claims 1 to 12, characterized in that the total layer thickness in the range of four over  lying layers is 10 to 40 mm. 14. Process for the production of panels according to one or more reren of claims 1 to 13, wherein the textile structure with the duropla tically bonded textile fiber fleece under the influence of the thermosetting binder pressed and glued.