CA2394790A1

CA2394790A1 - Plastic composite unit

Info

Publication number: CA2394790A1
Application number: CA002394790A
Authority: CA
Inventors: Joachim Wagenblast; Hubert Goldbach
Original assignee: Individual
Current assignee: Bayer AG
Priority date: 1999-11-25
Filing date: 2000-11-13
Publication date: 2001-05-31
Also published as: BR0015839A; WO2001038063A1; DE19956607A1; TR200201389T2; EP1235675A1; CZ20021800A3; PL355567A1; SK7322002A3; NO20022469L; CN1399590A; ZA200202982B; MXPA02005171A; NO20022469D0; JP2003514693A; KR20020053092A; AU2157801A

Abstract

The invention relates to a plastic composite unit, which is comprised of at least two flat workpieces made of different materials, e.g. of metal and plastic, and of different metals or plastics. The workpieces are interconnected in the edge area thereof, whereby the connection consists of a thermoplastic which is formed thereon.

Description

_ r _ -1-Plastic composite component The invention relates to a plastic composite component which is composed of at least two flat workpieces made of different material, e.g., metal and plastic, different 5metals or different plastics, which are joined together in their edge region, characterised in that the connections of the workpieces are composed of moulded-on thermoplastic.
The positive-fit connection of flat components made of different materials is obtained by forming a thermoplastic material.
The composite component fulfils different technical functions in different areas. For example, it combines high-strength, heat-resistant components and components suitable for cathodic electrocoating with made-to-measure workpieces in functional zones.
Composite components or semi-finished goods used in practice are composed of, e.g., flat composites in which, e.g., two metal sheets are joined by means of a plastic or plastic foam lying in between to form a sandwich structure (cf., EP 489 320 A1, EP 285 974 Al and EP 547 664 A2). Moreover, processes exist for the manufacture of composite sheets with external metal sheets and an internal rib structure (see EP
775 573 A2). Moreover, processes exist for joining metal sheets by a combination of pressing and injection moulding in a mould (EP 721 831 A1). Moreover, plastic/metal composite components are known in which metal sheets are supported by rib structures (EP 370 342 A3).
The composite components and composite semi-finished goods customary in the prior art and described in the literature are designed to achieve a uniform high strength and stiffness over the entire component, or sound and thermal insulation.
Certain special applications require, however, that a sheet, for example, must fulfil different technical requirements at different places of the sheet. This may mean that y , an insulating function is required on one half of the sheet and only connections to other separate components or structural elements, or the closure of openings, is to be achieved with the other half of the same component. If, for example, conventional composite sheets are used in this case, the component as a whole is over-specified in terms of its functions, and therefore too difficult or too complicated to manufacture.
The object of the invention is, therefore, to provide a composite component of the kind mentioned at the beginning which, in the various regions of the component, combines the particular acoustic, mechanical, optical or other material properties required for the functions of the component to be fulfilled in each case.
The object according to the invention is achieved by providing a component which is composed of at least two different regions executed in different materials which are joined together to obtain a positive fit by forming a thermoplastic.
The invention provides a plastic composite component composed of at least two flat workpieces made of different material, particularly of different metal, different plastic, or metal and plastic parts which are joined together in their edge region, characterised in that the joint is composed of moulded-on, particularly injection moulded thermoplastic, and in particular at least one workpiece in the region of the joint is penetrated or surrounded by the thermoplastic to obtain a positive fit.
Suitable high-strength metal materials include steel, aluminium, magnesium.
The workpieces may be composed of ceramic, thermosets or plastic composite materials.
Suitable thermoplastics, both as a material for the workpieces and for the joint, include unreinforced or reinforced, optionally filled plastics such as polyamide, particularly polyamide-6, polyamide-6.6, polyamide-12, polyamide-11 or polyesters, particularly polyethylene terephthalate, polybutylene terephthalate, or polyolefins, particularly polypropylene, styrene copolymers, particularly SAN resin or ABS, or polycarbonate, polypropylene oxide, polyphenylene sulfide, polyimide, PSO or PEEK, or possible mixtures of the plastics mentioned.

. WO 01/38063 CA 02394790 2002-05-22 PCT/EP00/11194 The composite component is a predominantly flat hybrid component which may contain linear or spot-type functional elements. Preferably defined joint regions are provided for at potential joints with other components, and said joint regions may be designed in various ways both in terms of shape, position and size and in terms of the material.
In a preferred form of the composite component, one of more workpieces of the composite component have apertures or recesses in the region of the joint through which are penetrated by injection moulded thermoplastic and form a positive-fit connection of the workpieces.
A particularly preferred embodiment of the composite component is characterised in that one of the workpieces is composed of the same thermoplastic as the joint.
In a preferred embodiment, one of the workpieces is composed of an elastomer, particularly a thermoplastic elastomer. Such components may be obtained, e.g., by the two-component injection moulding method known in principle.
The elastomers are preferably thermoplastic polyolefin and thermoplastic polyurethane.
If necessary, in a preferred embodiment of the invention, one of the workpieces of the component for screening electromagnetic radiation is manufactured from a metal which is joined to further non-metallic workpieces.
Workpieces of the composite component according to the invention which are to be connected to a structure different from the composite component, or to other components, may be selected freely according to the joining or connecting method suitable therefor.

If the plastic composite component according to the invention is to be welded, e.g., with a steel frame, the workpiece adjoining the frame will be a weldable sheet steel.
In this way, it becomes possible to fix the entire plastic composite component according to the invention at various places to external components or structures with completely different joining methods, e.g., by metal welding and plastic friction welding.
The invention also provides the use of the plastic composite component as a structural element for machines and vehicles, particularly motor vehicles, for electronic articles, household articles or for building requisites.
The workpieces are joined together in the form of metal sheets, panels, sheets, profiles (open or closed profiles) or hollow chambers. The type of material, the number and shape of the workpieces may be varied at will. In a preferred embodiment, flat workpieces, e.g., metal sheets and plastic sheets are joined together at their edges to obtain a positive fit. To this end, rivet heads made of thermoplastics which permit a firm connection to the high-strength workpiece (e.g., metal sheet) are moulded on in the region of superimposed apertures at the joint.
In this way, several high-strength workpieces may also be joined together. The function of the plastic may be restricted to the cohesion of the high-strength workpieces in the form of rivet heads.
Moreover, there is the possibility of creating a composite component composed of several high-strength workpieces joined together directly which are likewise secured by means of plastic rivet connections, the plastic component also, however, assuming other functions e.g., in the form of a moulded-on plastic sheet.
By attaching flexible components made of flexible thermoplastics, thermoplastic elastomers or elastomers between high-strength, inflexible or rigid regions of the composite component, the dynamic behaviour or the entire component is improved or the assembly of the component is facilitated. Moreover, by designing the flexible workpieces as a film hinge, the component may be rendered partially movable.
In occasional places of a component, screening of electromagnetic radiation may be achieved by using metal sheets as the workpiece which are joined to non-conductive materials, e.g., thermoplastics or other non-metallic workpieces.
Any joints of the component according to the invention to other components or structures may, due to the positive-fit connection of the individual workpieces, be executed in all materials known in principle. The joining method may be chosen at will.
When a highly heat-resistant plastic is selected (polyamide, polybutylene terephthalate, polyethylene terephthalate, polypropylene oxide, PSO, polyphenylene sulfide, polyimide, PEEK, or mixtures of said materials in an unreinforced or unfilled and in a fibre-reinforced or filled design), good heat resistance and suitability of the composite component for cathodic electrocoating may be obtained in conjunction with the positive-fit joining of the workpieces.
The composite component may be produced in various ways. The type of connection of, e.g., plastic and high-strength component (metal workpiece) is predominantly different:
1. Positive-fit connection of plastic workpiece and high-strength workpiece by material forming.
In this method of production, the connection may be obtained both by injection moulding and by plastic riveting by means of joining elements moulded on beforehand. In both cases, the high-strength workpiece is provided with apertures in the region of the joint (e.g., metal sheet with bored holes in the edge region), through which thermoplastic penetrates and a positive-fit connection is thus achieved.

Where the connection is obtained by injection moulding, a metal sheet, for example, is first inserted in an injection mould. As a result of the injection moulding process, both a less strong workpiece in the form of, e.g., a sheet is obtained and the connection with the metal sheet is achieved. As the plastic material is introduced in the liquid form into the injection mould, it is able to flow through apertures in the metal sheet and form rivet heads on the reverse of the metal sheet. In this way, various parts of metal or composite materials may be joined together in one process step directly or indirectly by means of regions made of thermoplastic material.
In a similar manner, a less strong workpiece may also be fixed to a high-strength workpiece by using plastic riveting. In this case, the thermoplastic is first injected separately, without metal sheet, but with moulded-on joining studs, into an injection mould. One or more metal sheets are then laid on the plastic part, the joining studs projecting through prepared apertures of the metal sheet(s). The joining studs are then formed to a rivet head by means of a forming process (e.g., by ultrasonic welding). Moreover, the welded joint may be carried out using separate auxiliary elements (e.g. stud welding), or achieved by joining two thermoplastic workpieces with moulded-on joining elements.
2. Positive-fit connection of a thermoplastic workpiece with a high-strength workpiece by means of snap connections. In this method, a plastic workpiece which is fitted with the requisite snap elements is produced first. For example, an injection moulded plastic part with moulded-on studs which are inserted into the prepared apertures of the high-strength workpiece may be used for this purpose.
Other possibilities of joining the workpieces consist in the use of various combinations of the methods mentioned. Consequently, it is possible to achieve positive-fit connections between the high-strength workpieces by attaching identical beads in both parts. A rivet joint may be attached by means of an additional identical aperture in both high-strength workpieces, e.g., by forming joining studs moulded onto the plastic part.
The advantages which may be obtained with the invention may be summarised as follows:
The composite component enables a flat composite to be obtained, composed of workpieces with materials which may be varied at will.
It is possible to design composite components of a partially different nature and level of stress to suit particular requirements.
The invention enables composite components with a partially different range of properties to be designed with optimised costs and weight.
The invention also allows a free choice of the joining method for joining with other components and structural elements, and the production of a flat composite of different materials in one process step.
The composite components according to the invention in the appropriate design find diverse applications as structural elements for machines, vehicles and components of all kinds, particularly for motor vehicles, electronic articles, household articles and for building requisites.
Particularly suitable applications for the composite component include structural parts for motor vehicles, doors, bumpers, supports, front and rear parts for passenger vehicles, side sill frames and decorative elements which combine increased strength with other material properties.
The invention is explained in more detail below on the basis of Figures.

_g_ Figure 1 shows a sheet 1 made of thermoplastic material to which a steel sheet 2 is fixed by a positive-fit connection;
Figure 2 shows the connection of two high-strength workpieces by means of a S medium-strength workpiece made of plastic;
Figure 3 shows the connection of several metal sheets by means of one workpiece made of thermoplastic polyurethane;
Figure 4 shows a detail of an underbody in the tunnel region of a motor vehicle.
Figure 5 shows a cross-section through a composite of three metal sheets with a turning.

Examples Example 1 Flat composite with partially different functions (Fig. 1) Fig. 1 shows a sheet 1 made of a thermoplastic material to which, on its left-hand end, a steel sheet 2 is fixed by means of positive-fit connections 6 to absorb concentrated forces. The left half of sheet 1 is provided on its upper side with a foam 3 for sound insulation. On the right half of sheet 1, sheet 1 is supported by two underlying U profiles 5 made of aluminium and an integrated rib structure 4 made of the same material as sheet 1 for absorbing relatively large flat loads. Sheet 1, rib structure 4 and all the positive-fit connections 6 of the joints are formed in this case by the thermoplastic component.
The composite component may be produced in two different ways. On the one hand, it is possible to insert the metal sheet 2, the foam 3 and the U profiles 5 into an appropriately shaped injection mould and then to inject the thermoplastic component with which sheet 1, the rib structure 4 and the positive-fit connections 6 are then produced. When the melt solidifies in the injection moulding process, the individual components are joined firmly to one another. In a second variant, the sheet 1 with the integrated rib structure 4 and the studs required for the positive-fit connections 6 is produced initially. The components comprising metal sheet 2, foam 3 and U
profiles 5 are then placed against sheet 1 in such a way that the studs of sheet 1 fit into the prepared apertures of components 2, 3 and 5. The studs are then formed to positive-fit connections 6 by ultrasonic welding.
Example 2 Cross-section through a composite made of three metal sheets: Fig. 2 _ - 10-Fig. 2 shows how different high-strength workpieces (metal sheets) may be joined together directly. The metal sheets 2 are provided in the edge region with a turning 11 so that the metal sheets 2 and 10 are joined together to achieve a positive fit. The positive-fit connection of the different metal sheets is secured by surrounding these S joints with the thermoplastic component 1S by injection moulding.
Example 3 Cross-section through a flexible composite made of metal sheets and thermoplastic elements (Fig. 3) In this Example, two metal sheets 2 are joined together in a flexible manner by means of an elastic sheet 9 made of thermoplastic polyurethane. The connection is formed by means of positive-fit connections 6 which are composed of the same 1 S material as that of sheet 9, in accordance with the explanations for Example 1 or 2.
A further metal sheet 12 is connected to the composite in another plane by means of a thermoplastic element 16 made of rigid plastic material. The elastic sheet 9 and the thermoplastic element 16 may be moulded onto metal sheets inserted in the injection mould in one step by two-component injection moulding.
Example 4 Cross-section through a vehicle underbody (Fig. 4) 2S Fig. 4 shows a section of an underbody in the tunnel region of a vehicle.
Floor panels 2, the tunnel metal sheet 7 and the tunnel cover 8 are each made of steel and joined together by means of the thermoplastic 17. The workpieces 2 and 7 are inserted in an injection mould and partially overpacked in their edge region with a thermoplastic. Joining studs are moulded on at the same time which, after the tunnel cover 8 has been put on, are formed in a subsequent operation to rivet connections 6 by ultrasonic welding.

According to this procedure, floor panels in vehicles may also be joined to the splashboard, or side members in the sill region may be joined to floor panels.
Example 5 Cross-section through a composite made of three metal sheets (Fig. 5) Fig. 5 shows how different high-strength workpieces (metal sheets) may be joined together directly. Metal sheets S2 and 10 are provided in the edge region with a turning S1 so that the metal sheets 52 and 10 are joined together to obtain a positive fit. The positive-fit connection of the different metal sheets 52 and 10 is secured by surrounding these joints with the thermoplastic component 55 by injection moulding.

Claims

claims

1. Plastic composite component composed of at least two flat workpieces (1) and (2) made of different material, particularly different metal, different plastic or metal and plastic parts, which are joined together in their edge region (13), characterised in that the joint (6) is composed of moulded-on, particularly injection moulded thermoplastic, and in particular at least one workpiece (1) or (2) is penetrated or surrounded by the thermoplastic in the region of the joint (6) to obtain a positive-fit connection.

2. Plastic composite component according to claim 1, characterised in that one or more workpieces of the composite component have, in region (13) of the joint (6), apertures or recesses which are penetrated by the thermoplastic and form a positive-fit connection of the workpieces.

3. Plastic composite component according to claim 1 or 2, characterised in that one of the workpieces (1) is composed of the same thermoplastic as joint (6).

4. Plastic composite component according to one of claims 1 to 3, characterised in that one of the workpieces (1) is composed of an elastomer, particularly a thermoplastic elastomer.

5. Plastic composite component according to claim 4, characterised in that the elastomer is a thermoplastic polyolefin or thermoplastic polyurethane.

6. Plastic composite component according to one of claims 1 to 5, characterised in that one of the workpieces (2) for screening electromagnetic radiation is composed of a metal which is joined to non-metallic workpieces (1).

7. Plastic composite component according to one of claims 1 to 6, characterised in that the thermoplastic is selected from the series comprising: polyamide, polyester, polyolefin, styrene copolymer, polycarbonate, polypropylene oxide, polyphenylene sulfide, polyimide, PSO or PEEK or possible mixtures of the polymers.

8. The use of the plastic composite component according to one of claims 1 to as a structural element for machines and vehicles, particularly motor vehicles, for electronic articles, household articles or building requisites.