DE102004027079B4 - Electrically heatable molded foam element, in particular seat element of a vehicle interior and method for its production - Google Patents

Abstract

electrical heatable molded foam element, in particular seat element of a motor vehicle interior trim (8), with an at least partially elastic body (16), with a cladding layer (10) on a surface and one between the surface of the body and the cladding layer arranged flat, stranded and / or textile heating element (12), characterized in that the flat, strand-like and / or textile heating element (12) and the surface of the body of the molded foam element (16) at least during the foaming process with at least one separating layer (14, 20, 22) shielded from each other are.

Description

The The present invention relates to an electrically heatable molded foam element, in particular seat element of a motor vehicle interior trim and a process for its preparation, according to the preambles of claims 1 and 13.

One electrically heatable molded foam element such as a Seat element of a vehicle interior equipment should make do with low heating current, The heating element should therefore be as close as possible on the surface be arranged of the molded foam element. On the other hand, in particular in a seat element, the heating element under the fabric not palpable his and one as possible evenly the entire surface having the molded foam element distributed heating effect. These requirements can be optimized by the use of textile heating elements, in particular with heating conductors made of thin, monofilament or multifilament carbon fibers fulfill. The carbon fibers can in this case twisted into a strand-like and / or textile structure and / or interweaves ("Carbotex").

electrical heatable molded foam elements such as seat elements for vehicle interiors are usually made gradually by a molded foam element and a flat, mostly on textile carrier material applied heating element first be prepared separately from each other, and then in connected to another operation, for example partially or over the entire surface glued, be.

The DE 37 25 408 A1 describes a method for producing a heatable vehicle seat, in which a support having foam conductors embedded in heating, is glued to a foam seat and then coated with a fabric.

In WO 01/19220 A1 is a method for applying heating conductors on a surface, for example, a surface a vehicle seat, by means of a temporary carrier layer and an adhesive layer disclosed. The carrier layer is removed after bonding the heating element with the surface. Also In this method, the vehicle seat is manufactured independently of the heating element.

Basically a molded foam element by lathering a foamable Plastic, such as polyurethane (PUR), in one with a Covering layer, for example a fabric cover, equipped Negative mold made. Heating elements are already in this Insert step in the molded foam element by clicking the inner surface the negative mold or the cladding layer, for example of the Fabric cover, applied and then foamed back with the foam. Such introduction of the heating elements leads to a significant simplification the manufacturing process of heated molded foam elements.

The Use of a strand-like and / or textile carbon fiber heating element in the described production process is according to the current state of Technology not possible. The direct foam back of multifilament Carbon fibers leads to their embrittlement, since the foam by capillary action in the one formed by them Structure penetrates, which encloses single strands of the fibers, and hardens in this position. The elasticity of multifilament Heating conductors is significantly affected, so that a mechanical Continuous load capacity of the heating element, especially in vehicle seats of highest importance is not achievable with this type of manufacture. In the Foaming Technique Therefore, the material "Carbotex" does not yet Use.

One The aim of the present invention is to provide an electrically heatable Molded foam element, in particular a seat element of a vehicle interior and to provide a method for its manufacture, in which a strand-like and / or textile heating element, in particular of multifilament carbon fibers, Backfoamed with foam so that the manufacture of the foam body and the introduction of the strand-like and / or textile heating element in a single Work step takes place, and at the same time the structure of the heating element Completely preserved.

This The aim of the invention is the subject of the independent claims 1 and 13 reached. Features of advantageous developments of the invention arise from the dependent ones claims 2 to 12 and 14 to 23.

One electrically heatable molded foam element of a vehicle interior according to claim 1 has an at least partially elastic foam body, the on a surface is provided with a cladding layer.

In principle, the molded foam element according to the invention can be any conceivable interior design in the vehicle that can be provided with a heating device. The molded foam body does not necessarily have an elastic structure, but may also be relatively dimensionally stable. As such electrically heatable molded foam elements In particular, seat cushions of vehicle seats come into question. However, the elements can also be backrest cushions or cheek pads of vehicle seats.

The Cladding layer may in particular be a textile fabric cover, however, you can other materials such as microfiber, leather, perforated leather, etc. find use.

According to the invention is between the surface the molded foam body and the cladding layer an electrical, Litzenartiges and / or textiles, multifilament Heating element arranged. This heating element is flat and consists in particular of a fabric of thin, electrical heating conductors, preferably from carbon fibers ("Carbotex").

According to the present Invention is the heating element on the of the cladding layer opposite side provided with a release layer, which has a capillary action prevents the Heizleitererstruktur on the foam material and therefore prevents penetration of the foam in the Heizleiterstruktur.

According to one preferred embodiment of present invention, the separation layer is wholly or at least partly from a hotmelt adhesive, for example on polyurethane (PUR) basis.

The Hot melt adhesive layer can each be the individual, multifilament Heizleiterfasern enclose. Alternatively, a hot melt adhesive, planar layer applied to the heat conductor layer with net-like, textile or fleece-like structure be. According to the invention, a area Coating as a carrier layer Serve by the electrical heating conductor fibers, in particular multifilamentöse Carbon fibers, fixed in their position and thus their transport and processing simplified. In addition, it allows the fixation of the heating element in the Negativform or on the located in the negative mold cladding layer, for example, a fabric cover, before foaming the foam. hereby becomes an exact positioning of the heating element in the molded foam element allows. In addition, can the fabric layer of or with hot melt adhesive of the formation of a Adhesive connection between the heating element and the molded foam element serve. For this purpose, the hot melt adhesive layer during or after the foaming process thermally melted, for example by a high temperature of the foam during the foaming process or by subsequent Creating a sufficient high voltage on the heating element. During the subsequent cooling is made the adhesive bond. The hot melt adhesive layer can no longer visible and / or detectable in the finished molded foam element be.

According to the present Invention may be the described layer of hot melt adhesive as a protective layer serve by allowing the foam mass to penetrate into the carbon fiber fabric during the Einschäumprozesses prevented. Thus, the foam material can not the individual carbon fibers wrap and also do not harden between individual threads, so that it is not a brittle fracture the fibers come. The elasticity The carbon fiber fabric remains largely intact, so too ensures the mechanical strength of the heating element in the long term is.

According to one another embodiment According to the present invention, the separating layer of film material, For example, polyurethane (PUR) or PUR-based exist. The film may be used alone as a single release layer, or in addition to a described separating layer of hot melt adhesive to its protective effect to increase, be introduced into the Heizelementaufbau. The foil can be perforated or be perforated to allow for air permeability preserve and the properties of the molded foam element not negative to influence. The perforation or perforation is preferably such executed that they are for the foam mass completely impermeable is. In a particularly preferred embodiment of the present invention Invention, the film material is such that it is during or after the foaming process, for example during of curing the foam mass, decomposes and thus no negative effects can point to the finished electrically heatable molded foam element. The air permeability the molded foam element would thus remain absolutely undisturbed, especially in the case of a vehicle seat, a good seat climate would remain receive. Also the stiffness or the noise properties, the foil materials would be no longer present in the finished molded foam element, so that in particular created a generally comfortable seating feeling in a vehicle seat becomes.

In a further alternative embodiment of the invention, the carbon fibers or alternatively the entire heating element may be cast in a gel or a layer of gel either alone or together with a layer of hotmelt adhesive and / or film on the side facing the foam body and / / or textile Heizleiterschicht be applied. This gel is preferably made of polyurethane ("technogel") .Besides the shielding of the carbon fibers from the foam material during the foam-back process, the gel layer can provide corrosion protection and thus also a long hold availability of the heating element serve.

at the use of a hot melt adhesive layer in conjunction with a or a plurality of further separating layers for shielding the strand-like and / or textile heating element of the foam mass, it is according to the invention of advantage, the Hot melt adhesive layer on the body of the molded foam element facing side of the Heizleiterschicht and in direct contact to install to the heating conductors. In this position, the hot melt adhesive layer additionally act as a carrier layer, the the Heizleitererstruktur for fixed the transport and / or its processing, and also the Heizelementfasern on the cladding layer, such as the fabric cover position and fix.

One inventive method for producing an electrically heatable molded foam element provides that a negative mold initially with a cladding layer, for example, a cover made of textile material, microfiber, leather, perforated leather or similar Material that is lined. This is then a strand-like and / or textile heating element, for example made of carbon fibers ("Carbotex"), inserted, or, if this is applied to a hot melt adhesive backing, glued. Alternatively, first a layer of gel material, in particular of PUR gel ("technogel"), are introduced, then positioned and fixed on the heating element structure can. Further separating layers, for example of film material, in particular PUR film, or gel material, in particular PUR gel, are also in the negative mold and on the panel and Gel layer and / or Heizleiterschicht applied. If everyone Layers are in the negative mold, a foam plastic, For example, polyurethane foam, foamed into the negative mold, the subsequently cured in the mold and thus permanently forms a three-dimensional foam body. An incorporated foil material may be such that it while or after the foaming process decomposed. A hot melt adhesive layer can either be by the temperature while the foaming process itself or by applying a heating voltage to the heating element after the foaming process, either before or after curing the foam material, an adhesive bond between the heating element and the foam body produce. The adhesive bond is preferably after decomposition made of the film. The hot melt adhesive layer can be finished Asked foam molding element no longer visible and / or detectable be.

One electrically heatable molded foam element such as a Seat element of a vehicle interior according to the present invention, which has a heating element, for example made of carbon fiber fabric, that by the method according to the invention while the foaming process is introduced into the molded foam element, has an optimal Stratification of the main elements: Between the cladding layer or the reference of the molded foam element and the heating element is located no more layer, the heat transfer could hamper. The electrode tracks are evenly distributed and at a close distance over each other the entire area to be heated away, allowing a uniform heating the surface takes place (property of "Carbotex") .The good characteristics, also regarding elasticity and mechanical durability, the heating conductor structure remain receive. Air permeability and elasticity the finished, electrically heatable molded foam element are guaranteed.

The present invention enables the use of strand-like and / or textile heating elements, for example made of multifilament Heating conductors, in particular of carbon, in the foaming technique and leads thus to a considerable simplification and improvement of electrical Heatable molded foam elements of vehicle interiors and their production. This corresponds to a huge market expansion for "Carbotex" or materials with similar Structure that are disturbed by the penetration of the foam mass can.

The Invention will now be described with reference to exemplary embodiments with reference explained in more detail in the accompanying drawings. Show it:

1 a sectional view of an inventive electrically heatable surface of a vehicle seat made of foam in a simple embodiment during the manufacturing process in the negative mold and

2 a sectional view of an inventive electrically heatable surface of a vehicle seat made of foam in an alternative embodiment, also during the manufacturing process in the negative mold.

In 1 is the structure of an electrically heatable molded foam element according to the invention on the example of a seat element of a vehicle interior 8th shown. The sectional view shows the layering of such an element: on the finished seat element 8th outwardly facing surface of the element is a fabric cover 10 which is directly on the inside of the negative mold 18 is applied. Directly below is a textile heat conductor layer 12 made of a carbon fiber tissue ("Carbotex") exists on the foam body 16 facing side of the heat conductor layer 12 is a textile or fleece-like release and carrier layer of hot melt adhesive 14 , which serves as a protective layer, by preventing penetration of the foam into the heat conductor fabric or between the individual strands of the multifilament heating conductor fibers 12 prevented during the Einschäumvorgangs. The body of the molded foam element 16 consists of a foamed plastic, for example, polyurethane. This will be in one with the fabric 10 , the heating element 12 and a hot melt adhesive layer 14 designed negative form 18 foamed and thereby brought into shape. The figure refers to the time directly after the foaming process, to which all layers are still visible.

2 shows the cross section of an alternative, more complex embodiment of the present invention. The structure of the electrically heatable molded foam element shown here 8th consists of the following layers from the outside to the inside: a fabric cover 10 ; a textile Heizleiterschicht 12 of a carbon fiber fabric ("Carbotex"); a textile or nonwoven release and carrier layer of hot melt adhesive 14 , which serves as a protective layer, by preventing penetration of the foam in the Heizleitergewebe 12 prevented during the foaming process; a film layer of polyurethane film 20 which provides additional protection against ingress of foam material into the "Carbotex" fabric, a layer of polyurethane ("Technogel") 22 , in addition to the shielding of the foam material 16 from the heat conductor structure 12 also represents a corrosion protection and the life of the seat element 8th elevated. The body 16 the molded foam element 8th consists of a foamed plastic, for example, polyurethane. This is in a negative form 18 foamed, in the previously a fabric 10 , a heating element 12 , a textile or non-woven hot melt adhesive layer 14 , a PUR film 20 and a PUR gel 22 was introduced. The heating conductor layer 12 can by means of hot melt adhesive layer 14 exactly on the fabric 10 be positioned and also the PUR film 20 fix. After the foaming process or during the curing of the plastic foam, the film layer can 20 decompose, so that they have no negative effects on the properties of the finished, electrically heatable molded foam element 8th such as airtightness or rigidity. The figure refers to the time directly after the foaming process, to which all layers are still visible.

The in the foregoing description, drawings and claims Features of the invention can both individually and in any combination for the realization the invention in its various embodiments of importance be. The invention is not limited to the above embodiments limited. Much more is a variety of variants and modifications conceivable by the idea according to the invention Use and therefore also fall within the scope of protection.

8th

electrical heatable molded foam element

10

reference

12

litzenartige and / or textile heat conductor layer

14

textile or non-woven separating layer of hot melt adhesive

16

Foam body of Molded foam element

18

negative form

20

Interface made of PUR film

22

Interface made of PUR gel ("Technogel")

Claims (23)

Electrically heatable shaped foam element, in particular seat element of a motor vehicle interior trim ( 8th ), with an at least partially elastic body ( 16 ), with a cladding layer ( 10 ) on a surface and between the surface of the body and the cladding layer arranged flat, stranded and / or textile heating element ( 12 ), characterized in that the flat, strand-like and / or textile heating element ( 12 ) and the surface of the body of the molded foam element ( 16 ) at least during the foaming process with at least one release layer ( 14 . 20 . 22 ) are shielded from each other. Element according to claim 1, characterized in that the strand-like and / or textile heating element ( 12 ) Comprises carbon fibers. Element according to claim 1 or 2, characterized in that at least one separating layer ( 14 ) Has hot melt adhesive. Element according to claim 3, characterized that the hot melt adhesive comprises polyurethane. Element according to claim 3 or 4, characterized in that at least one separating layer ( 14 ) is flat and has a textile or non-woven structure. Element according to one of the preceding claims, characterized in that at least one separating layer ( 20 ) Comprises film material. Element according to claim 6, characterized in that the film layer ( 20 ) Polyurethane. Element according to claim 6 or 7, characterized that the film material is perforated or perforated. Element according to one of Claims 6 to 8, characterized that the film material chosen so Is that it is preferably by thermal melting during or decomposes after the manufacturing process of the molded foam element. Element according to one of the preceding claims, characterized in that at least one separating layer ( 22 ) Has gel material. Element according to one of claims 1 to 9, characterized in that the heating conductors ( 12 ) and / or a separating layer of hotmelt adhesive ( 14 ) and / or a release layer of film material ( 20 ) surrounded by gel material. Element according to claim 10 or 11, characterized that the gel material comprises polyurethane. Method for producing an electrically heatable shaped foam element with an at least partially elastic body ( 16 ), with a cladding layer ( 10 ) on a surface and between the surface of the body and the cladding layer arranged flat, stranded and / or textile heating element ( 12 ), in particular an electrically heatable molded foam element according to one of claims 1 to 12, characterized in that the strand-like and / or textile heating element ( 12 ) on the inside of the cladding layer ( 10 ) and then with at least one release layer ( 14 . 20 . 22 ) and with a foam ( 16 ), in particular polyurethane, is backfoamed. A method according to claim 13, characterized in that at least one, the strand-like and / or textile heating element ( 12 ) carrying, separating layer ( 14 ) Has hot melt adhesive by means of which the strand-like and / or textile heating element ( 12 ) on the inside of the fairing ( 10 ) is fixed. A method according to claim 14, characterized in that the Hinterschäumungsvorgang takes place at such a high temperature that the consisting of hot melt adhesive textile and / or non-woven carrier ( 14 ) of the heating element ( 12 ) an adhesive bond between the molded foam element ( 16 ) and the heating element ( 12 ). A method according to claim 14, characterized in that after the Hinterschäumungsvorgang a heating voltage to the heating element ( 12 ), which results in a melting of the hot melt adhesive textile or nonwoven support ( 14 ), and that then takes place a cooling process, during which the hot melt adhesive hardens and an adhesive bond between the molded foam element ( 16 ) and the heating element ( 12 ). Method according to one of claims 13 to 16, characterized in that at least one release layer ( 20 ) is used with film material. A method according to claim 17, characterized in that for the film layer ( 20 ) Polyurethane is used. Method according to claim 17 or 18, characterized that the film material is perforated or perforated. Method according to one of claims 17 to 19, characterized that the film material during or after the foam process decomposed. Method according to one of claims 13 to 20, characterized in that at least one release layer ( 22 ) is used with gel material. Method according to one of claims 13 to 20, characterized in that the heating conductors ( 12 ) and / or a separating layer of hotmelt adhesive ( 14 ) and / or a release layer of film material ( 20 ) surrounded by gel material. Method according to claim 21 or 22, characterized that for the, gel material polyurethane is used.