MEHRLAGIGES VERBUNDMATERIAL FÜR DIE HERSTELLUNG VON KUNSTSTOFFFORMTEILEN, BEHÄLTER AUS EINEM SOLCHEN VERBUNDMATERIAL SOWIE VERFAHREN ZUR HERSTELLUNG DES BEHÄLTERS

A multi-layer composite material for the production of plastic moldings, container from such a

Composite material and

A process for the manufacture of the container

The invention relates to a multi-ply composite material for the manufacture of plastic molded parts. More particularly, the invention relates to a multi-ply composite material for the manufacture of pressure-resistant, thin-walled vessels such as fuel tanks for motor vehicles.

The invention further relates to a method for producing a container from a multilayer composite material.

Particularly in the development of plastic molded parts for automotive purposes play a significant role weight savings. In addition, however, the dimensional stability of plastic molded parts in the automotive industry is critical, particularly in the production of built-in motor vehicles containers such as fuel tanks, urea tanks or other secondary liquid containers. Such containers, particularly plastic fuel tanks, are often referred to as single or multi-part container based on polyethylene (HDPE) is formed. In particular, fuel tank for gasoline have a multi-layer wall construction with barrier layers for hydrocarbons or have been made resistant by chemical treatment to hydrocarbons.

Plastic fuel tank based on HDPE have the advantage that they can be produced with a spatially relatively complex shape and are sufficiently resistant to deformation and stable. Even such fuel tanks are sufficiently shock resistant so that these corresponding impact forces can withstand in a crash. Short-term deformations of a fuel tank in the event of a crash does not usually lead to permanent changes in contour. The known fuel tank made of plastic are largely dimensionally stable, at least such that they assume their original shape again when the pressure even at short notice increased internal pressure.

Thermoplastics, however, are attended by the disadvantage that the thermoplastic material tends at longer applied deformation forces to creep. Materials based on HDPE, they are one or more layers are therefore generally suitable not readily adaptable for the production of containers that have to withstand increased internal pressure for long periods. Already a positive pressure in the order of about 400 mbar resulting in a container on the basis of HDPE over extended periods of time cause permanent deformation of the material.

Container and molded parts made of polyethylene or polyamide or on the basis of polyethylene also have the disadvantage that a sufficient stability can only be achieved through correspondingly large wall thicknesses of the components. Weight savings in such plastic moldings only by design measures are only to a limited extent, which is why plastic moldings made of fiber composite materials play an increasing role in the automotive industry.

From DE 10 2010 027 096 Al a fuel tank made of plastic with a multilayer container is known, for example, comprising an inner layer of thermoplastic material and an outer layer of a fiber composite material. These layers are bonded to each other, wherein a multilayer extrudate is provided on the basis of polyethylene with a barrier layer for hydrocarbons as the inner layer.

Such a composite material has, that the container prepared therefrom having an outer relatively rigid and lightweight location preference, whereas the inner layer has a certain resilience, and in particular ensures the tightness of the container.

However, composite materials such as high-strength organic sheets tend to impact-induced deformation forces at low temperatures when exposed

Brittle fractures.

Experience has shown that in the combination of brittle and ductile plastic layers that are bonded to each other and thus form a composite layer, tend to crack formation in the hard and brittle layer tends to propagate in the ductile layer when the ductile layer is not a certain wall thickness having. As a result, significant weight savings of plastic molded parts made of a composite material, as for example, in

DE 10 2010 027 096 describes AI, are not possible by the reduction of layer thicknesses of the composite forming materials.

The invention is therefore based on the object to provide a multilayer composite material for the production of plastic parts, in particular for the production of containers, for example fuel tanks or other operating fluid containers, for motor vehicles, which is particularly lightweight and shatterproof. In addition, the composite material should also have barrier properties, that is, substantially prevent a molecular mass transport of liquid and gaseous substances through the material.

The object is achieved by a multi-ply composite material for the manufacture of plastic molded parts according to the claim. 1

According to the invention, a container made of such a multilayer composite material is further provided. Finally, the invention also comprises a method for manufacturing such a container according to the invention of a multilayer composite material.

Advantageous embodiments of the invention are respectively detected by the subclaims.

One aspect of the invention relates to a multi-ply composite material for the manufacture of molded plastic parts comprising:

- a first structuring, self-supporting stiff

Outer layer of a fiber composite material,

a second structuring outer layer

a tear-resistant intermediate layer of a plastic selected from a group comprising tear-resistant modified polyethylene, polyisobutylene,

Polyvinyl butyral, ethylene vinyl acetate, polyacrylate, polymethylene, polyurethane, prestretched

Polypropylene, polyvinyl acetate and ethylene vinyl acetate and at least one adhesive layer,

wherein the intermediate layer and the adhesive layers are embedded between the structuring outer layers, forming an adhesive bond with the structuring outer layers and wherein the structure-giving

Outer layers each have a thickness which is a multiple of the thickness of the intermediate layer or the adhesive layer. In particular, the tear-resistant intermediate layer can absorb introduced into the composite material fracture energy so that, for example, when the first structuring self-supporting rigid outer layer cracks, such a formation of cracks does not continue in the other layers of the composite material. A tear-resistant intermediate layer according to the invention is preferably a thin tear-resistant film having an elongation at break of> 300%.

As a tear-resistant intermediate layer thin, tear-resistant films are concerned, which form with the surrounding layers of a cohesive composite in the sense of bonding. The tear-resistant intermediate layer thus keeps the

Layers laminated together in any case so that a total of the multi-layer composite material having a high resistance to breakage at low material thickness. The tear-resistant intermediate layer may for example have a thickness between about 50 pm and 1520 pm, more preferably between 50 pm and 300 pm, comprise. Basically, the second structuring outer layer may also consist of a fiber composite material.

Basically, the multi-layered composite material can according to the present invention include a variety of structure-giving and self-supporting rigid layers between which tear-resistant intermediate layers are respectively arranged. Although the structuring outer layers may also form the outermost layers in the sense of the present invention, and also do so preferably, is also contemplated within the scope of the invention that additional layers may be arranged on the structure-imparting outer layers, so that the structure-providing outer layers do not necessarily constitute the outermost layers ,

The second structuring outer layer may comprise one or more thermoplastic polymers selected from a group comprising polyethylenes, polyamides, polyphenylene sulfides, polybutylene terephthalates, polyketones, polyetheretherketones, liquid crystal

Polymers and polyphthalamides. The second structuring outer layer may consist of a polyolefin or a polyamide, and have for example a thickness of between 0.5 and 1.5 mm.

In a preferred variant of the multi-layer composite material described above is provided that the second structuring outer layer an HDPE film (High Density Polyethylene) or a PA layer. This layer of HDPE or PA (polyamide) for example can serve as a protective layer for an interlayer of a barrier resin or as a so-called welding reserve. As welding reserve in general layers of a plastic molded part be referred to ensure a weld other plastic molded parts without the provision of additional welding materials or adhesives. The fiber composite material according to the present invention, a material with a thermoplastic or a duoplastischen matrix in these embedded long fibers or so-called "continuous fibers" is provided, wherein the long fibers or continuous fibers are selected from a group comprising glass fibers, carbon fibers and aramid fibers and the long fibers or continuous fibers are woven or laid.

Under a long fiber for the purposes of the present invention is meant a fiber having a length between 1 mm and 50 mm. Under a continuous fiber according to the present invention is meant a fiber having a length of more than 50 mm.

Under a specified set long fiber or continuous filament according to the present invention is to be understood an arrangement of long or continuous fibers, which are not connected by so-called warp and weft threads in the sense of a tissue. Here is understood to mean a loosely oriented and stacked assembly of long fibers or continuous fibers in the matrix material. The fiber composite material according to the present invention are, in particular so-called organic sheets into consideration. Among these, a fiber-matrix semifinished product is generally understood as comprising a fiber fabric or a fiber fabric which is embedded into a thermoplastic plastics matrix. A batt is an assembly of continuous fibers or long fibers defined in the present definition. The multilayer composite material according to the invention preferably further comprises a further intermediate layer of a barrier plastics. Under a barrier resin within the meaning of the present invention, a plastic is to be understood, which is non-porous for liquid and gaseous substances not or substantially, which means that takes place through this no appreciable molecular mass transport of liquid and gaseous substances in terms of permeation.

The barrier resin may be selected, for example, comprising Polyvinyllidenchlorid from a group (PVDC), ethylene vinyl alcohol copolymer (EVOH), liquid crystal polymer (LCP), polyamide 6 (PA 6), cellulose and biaxially oriented polypropylene (BOPP).

Particularly suitable as a barrier plastic is EVOH. As an adhesion promoter for example a maleic anhydride modified LDPE (Low Density Polyethylene) or LLDPE is provided.

The multilayer composite material according to a variant of the invention is characterized by a layered structure comprising in sequence an outer layer of a thermoplastic material selected from a group comprising polyethylene, polyamides, polyphenylene sulfides, polybutylene terephthalates, polyketones, polyetheretherketones, liquid crystal polymers and polyphthalamides, a tear-resistant intermediate layer, and a layer of from a fiber composite material. The fiber composite material itself may be formed in multiple layers, wherein between the individual fiber layers, which are each embedded in a matrix material in the form of a thermoplastic or thermosetting plastic regard, in each case a tear-resistant intermediate layer may be disposed.

The multilayer composite material according to another variant of the invention by an outer layer of a thermoplastic material selected a layered structure comprising, in order from a group comprising polyethylene, polyamides, polyphenylene sulfides,

include polybutylene terephthalates, polyketones, polyetheretherketones, liquid crystal polymers and polyphthalamides, an adjacent first adhesive layer, an intermediate layer of a barrier resin, a second adhesive layer, a tear-resistant intermediate layer, and optionally a third adhesive layer and a structuring outer layer of a fiber composite material.

In principle, the thickness of the structural layers is between 0.5 mm and 2 mm, preferably between 1 and 1.5 mm, whereas the thickness of the intermediate layers, that is, both the intermediate layer of barrier resin and the tear-resistant intermediate layer, and the

Adhesion-promoting layer in each case between 50 pm and 1520 pm may be.

Another aspect of the present invention relates to a container made of a multilayer composite material of the type described above, wherein the first structuring outer layer is an outer layer of the container and wherein the second structuring outer layer is an inner layer of the container. In particular, when the second structuring outer layer of HDPE or PA exists, it is simply possible to produce the container according to the invention of several shells, which are superposed with the inner layers are welded together.

A preferred embodiment of the container according to the invention is designed as a fuel tank for a motor vehicle.

As already mentioned above, the container consists of two shell-shaped molded parts may be assembled comprising an upper shell and a lower shell, the upper shell and the lower shell are welded together, for example, to flange-like edges can be. The terms "upper shell" and "shell" refer respectively to the mounting position of the container. The invention further provides a process for producing a container from a multilayer composite material having the features described above is provided, wherein the method comprises the following steps: - providing fiber-matrix semi-finished products as fiber

Composite,

Heating and plasticizing the fiber-matrix semi-finished products, forming the fiber-matrix semi-finished products to the cup-shaped intermediate products,

- providing a multilayer plasticized extrudate comprising a structure-giving layer of a thermoplastic material selected from a group comprising polyethylene, polyamides,

Polyphenylene sulfides, polybutylene terephthalates, polyketones, polyetheretherketones, liquid crystal polymers and polyphthalamides and at least one intermediate layer,

Introducing the plastic extrudate in the plasticized and deformed fiber-matrix semi-finished products and integral joining of the fiber-matrix semifinished product and of the extrudate by utilizing the

Plastifizierungswärme and / or by means of a

Adhesion promoter.

The multilayer extrudate can comprise a plurality of intermediate layers, one of which may be made an intermediate layer of a barrier resin least. When a compound of the fiber-matrix semifinished product and of the extrudate by utilizing the Plastifizierungswärme the introduction of the plastic extrudate in the plasticized and deformed fiber-matrix semi-finished products as well as the cohesive bonding of the fiber-matrix semifinished product and of the extrudate takes place almost simultaneously.

The extrudate can, for example, m known manner be provided as co-extruded from an extrusion head an extrusion blow molding.

The method may basically the plasticizing of fiber-matrix semi-finished products with a thermoplastic matrix, the introduction of these fiber-matrix semi-finished products in a Extrusionsblasformwerkzeug and the so-called blowing a multi-layer extrudate in the

Extrusionsblasformwerkzeug include against the already molded in the tool fiber-matrix semifinished product. Within the scope of the invention is the lamination of a multilayer composite material according to the present invention to plate-shaped semifinished products, which are then transformed into the second heat, that is, by re-heating to the cup-shaped intermediate products. The production of the cup-shaped intermediate products can take place in this case, for example, by conventional thermoforming equipment. The invention is explained below with reference to an embodiment shown in the drawings embodiment. It show:

1 shows a layer structure of a multilayer

Composite material according to a first

Embodiment of the invention, and

2 shows a layer structure of a multilayer

Composite material according to a second embodiment of the invention.

A layered structure of a multilayer composite material according to the invention is for example shown in the attached FIG. 1

1 shows a schematic layer structure of a composite material 1 according to the invention comprising a first structure-providing outer layer 2 of a

Fiber composite material and a second structuring outer layer 3 of HDPE. The layer-section shown in Figure 1 illustrates the wall structure of a container according to the invention. The first and second structure-providing outer layers 2 and 3 are respectively the outermost layers of the container wall, wherein the first structuring outer layer 2 forms an outside of the container and the second structuring outer layer 3 forms an inner side of the container.

Between the first structuring outer layer 2 and the second structuring outer layer 3 first and second intermediate layers 4 and 5 are arranged, which are each formed as thin films having a layer thickness between 50 and 300 pm. These layers are flexibly and no structure-imparting layers in the context of the invention. The second intermediate layer 5 is formed as a tear-resistant intermediate layer according to the present invention, whereas the first intermediate layer 4 consists of a barrier resin. The first structuring outer layer 2 consists of a fiber composite material embedded in a thermoplastic matrix continuous fiber, the second structuring outer layer 3, which forms the inner layer of the container is made of a HDPE. The first structuring outer layer 2 and the second structuring outer layer 3 are both formed self-supporting stiff and have a layer thickness of about 0.5 to 2 mm respectively.

Although the first structuring outer layer 2 forms the outside of the container, but the invention is to be understood that this first structuring outer layer 2 may externally be provided with a protective lacquer.

The first intermediate layer 4 is in the described embodiment, preferably a layer of EVOH (ethylene vinyl alcohol copolymer), which is embedded in a first and second adhesive layer 6. 7 The second intermediate layer 5 consists, for example from a polyisobutylene and is designed as a tear-resistant intermediate layer or film according to the invention. The second intermediate layer 5 is interposed between the second adhesive layer 7 and a third

Adhesive layer 8 embedded, so that a bonding of the layered composite is effected via the second intermediate layer. 5 The second intermediate layer 5 as a tear-resistant, thin film increases, for example, at an impact load of the first structuring outer layer 2, the ductile fracture energy, so as to forming cracks can not propagate in the first intermediate layer 4 and in the second structuring outer layer. 3

A second embodiment of the invention is shown in FIG. 2 In this embodiment, layers that correspond to those of the embodiment of Figure 1, provided with the same reference. The second embodiment of the invention differs from the first embodiment in that the first structuring outer layer 2 is formed in multiple layers in itself. This consists of a fiber composite material comprising a first fiber layer 9, and a second fiber layer 10, which are each embedded in a matrix material in the form of a thermoplastic or thermosetting plastic and which are separated by an intermediate layer 5 as a tear-resistant interlayer from each other. The intermediate layer 5 forms, optionally via further adhesive layers, an adhesive bond with the fiber layers 9,10. LIST OF REFERENCE NUMBERS

1 multi-layered composite material

2 first structuring outer layer 3 second structuring outer layer

4 first intermediate layer

5 second intermediate layer

6 first adhesive layer

7 second adhesive layer

8 third adhesive layer

9 first fiber layer

10 second fiber layer