GB2349599A

GB2349599A - Manufacturing method for composite

Info

Publication number: GB2349599A
Application number: GB9910350A
Authority: GB
Inventors: Nicholas Tucker
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1999-05-06
Filing date: 1999-05-06
Publication date: 2000-11-08
Also published as: GB9910350D0

Abstract

A method of producing a composite is disclosed in which a first layer 24 of fibres is laid up in a first pan of a mould cavity, a quantity of thermoplastic 27 is then introduced over an uppermost surface of the first layer of fibres 24 before a second layer 22 of fibres is laid up over the thermoplastic 27. The mould cavity is then closed to compress the layers of fibres 22,24 and the thermoplastic 27 together such that the thermoplastic 27 permeates through the layers of fibres 22,24 to a surface 14 of the mould cavity. The thermoplastic 27 and fibre layers 22,24 are preferably made of a biodegradable material. The thermoplastic 27 is preferably introduced to the mould cavity by extrusion or injection. The thermoplastic 27 may also include automotive shredder residue.

Description

Manufacturing Method The present invention relates to a method of manufacture of a composite component and to a component produced by the method. Such a composite component has particular, but not exclusive, utility in the automotive field.

According to the present invention, a method of producing a composite comprises the steps of: providing a first part of a mould defining a first part of a mould cavity having a surface; laying up a first layer of fibres in the first part of the mould; introducing a quantity of thermoplastic to the first part of the mould over an uppermost surface of the first layer of fibres; laying up a second layer of fibres over the thermoplastic; providing a second part of the mould defining a second part of the mould cavity to complete the mould cavity; bringing the first and second mould parts together to compress the fibres and the thermoplastic together such that the thermoplastic permeates through the layers of fibres to the surface of the mould cavity.

Preferably, the thermoplastic comprises a biodegradable thermoplastic.

Preferably, the biodegradable thermoplastic includes biodegradable filler material such as miscanthus fibres.

Preferably, the thermoplastic includes up to 30 per cent automotive shredder residue.

Preferably, the fibres comprise biodegradable fibres. More preferably, the biodegradable fibres comprise hemp, jute, or the like.

Preferably, the quantity of the thermoplastic is introduced to the mould by an extrusion apparatus.

Preferably, the layers of fibres comprise one or more sheets of woven or non woven fibres. More preferably, the first and second layers contain equal numbers of sheets of woven or non woven fibres.

The invention will now be described, by way of example only, with reference to the accompanying Figures, in which: Figure 1 shows a diagrammatic side section of an apparatus suitable for use in performing the method of the present invention; Figure 2 shows a section through a first composite component produced in accordance with the present invention; and Figure 3 shows a section through a second composite component produced in accordance with the present invention.

Referring first to Figure 1, an apparatus suitable for use in performing the method of the present invention will now be described.

A mould apparatus 10 is shown having a first mould part 11 and a second mould part 12. The first mould part 11 defines a first part of a mould cavity. The second mould part 12 defines a second part of the mould cavity. The mould cavity has an inner surface 14 defined by the parts of the mould cavity. The first and second mould parts may be displaced relative to one another to open and close the mould cavity as indicated by arrow A.

An extruder 16 is provided to heat a thermoplastic and subsequently extrude a quantity of the heated thermoplastic. The extruder may be moveable as indicated by arrow B between a first position clear of the mould, and a second position in which it may extrude the heated thermoplastic. Alternatively, an injector may be used for the same purpose.

While the first and second mould parts are separated from one another, a first layer 24 of fibres is laid up in the first mould part. The first layer of fibres may comprise one or more separate sheets of woven or non woven fibres. For the purposes of clarity, the first layer comprises only a single sheet of fibres in Figure 1. For preference, the fibres comprise biodegradable fibres, for example cellulosic fibres from an agricultural crop such as jute or hemp. Alternatively, the fibres may be formed from a plastic, such as a biodegradable thermoplastic.

When the first layer of fibres has been laid up, the extruder is moved from the first position to the second position. The extruder 16 then extrudes a quantity of thermoplastic 27 onto an uppermost surface of the first layer 24 of fibres. The thermoplastic may include a filler material 28. This also may be a cellulosic material obtained from an agricultural crop, for example miscanthus fibres. The extruder is then returned to the first position.

Before the thermoplastic 27 is allowed to cool, a second layer 22 of fibres is laid up over the thermoplastic. As with the first layer of fibres, the second layer may comprise one or more separate sheets of woven or non woven fibres. Again, for the purposes of clarity, the second layer is shown comprising only a single sheet of fibres in Figure 1. As for the first layer, the fibres may comprise cellulosic fibres from an agricultural crop such as jute or hemp. Alternatively, the fibres may be formed from a plastic, such as a biodegradable thermoplastic.

The first and second layers 22, 24 are typically of equal thickness. The first and second layers 22,24 typically comprise similar biodegradable fibres.

The first and second mould parts 11,12 are then brought together to close the mould cavity and to compress the layers 22,24 of fibres and the thermoplastic 27 together. This has the effect of forcing the thermoplastic to permeate through the first and second layers of fibres to the surface 14 of the mould cavity to form a surface of the resulting composite component.

The thermoplastic 27 is allowed to cool before the mould cavity is opened and the formed composite component removed from the mould. In this way, the surface finish of the formed composite component is determined by the finish of the surface of the mould cavity.

In the illustrated embodiment of the invention, the first and second layers of fibres contain equal numbers of sheets of woven or non woven fibres. This has been found not to produce undesirable stresses on the upper and lower surfaces of the formed composite which may lead to undesired twisting or curving of the formed composite component.

In Figure 2 there is shown a section through a first composite component 21 produced in accordance with the method of the present invention. A first layer 22 of fibres is disposed towards an upper surface 23 of the composite component. A second layer 24 of fibres is disposed towards a lower surface 25 of the composite component.

A layer 26 of thermoplastic 27 is disposed between the first and second layers 22,24 of fibres. The thermoplastic permeates through each of the first and second layers of fibres to the upper and lower surfaces of the composite component.

At the end of the life of a motor vehicle, the motor vehicle is scrapped. Many of the parts may be either reclaimed for reuse or recycled by a processing route, for example thermoplastics parts may be melted and moulded into new components. Indeed, there is an increasing drive to increase the proportion of materials salvaged in this way. However, those parts that are not currently reclaimed or recycled are shredded to form automotive shredder residue. Automotive shredder residue is currently disposed of as landfill. Typically, automotive shredder residue comprises fragments of glass, plastics and wood, pieces of metal such as small springs, hydrocarbon residues such as brake fluid and oil, mud and dirt. As such, automotive shredder residue frequently has an extremely pungent, unpleasant odour.

However, increased taxes and other environmental legislation is making disposal of such automotive shredder residue as landfill an increasingly unattractive option. Accordingly, there is a need for an alternative disposal route for automotive shredder residue other than as landfill.

In Figure 3 there is shown a section through a second composite component 31, which includes a quantity of automotive shredder residue, produced in accordance with the present invention. A first layer 32 of fibres is disposed towards an upper surface 33 of the composite component. A second layer 34 of fibres is disposed towards a lower surface 35 of the composite component.

A layer 36 of thermoplastic 37 is disposed between the first and second layers 32,34 of fibres. The thermoplastic permeates through each of the first and second layers of fibres to the upper and lower surfaces of the composite component.

A quantity of automotive shredder residue 38, up to 30 per cent, is included in the thermoplastic 37 prior to melting and injection or extrusion onto the first layer of fibres. The automotive shredder residue 38 may conveniently be further shredded or ground or both, and then mixed with the thermoplastic 37 prior to use with an extruder or injector. This helps prevent any untoward damage of the extruder or injector by fragments of the automotive shredder residue.

When the thermoplastic 37 including the automotive shredder residue 38 is compressed, the molten thermoplastic 37 is forced to permeate through the first and second layers 32,34 of fibres to the surface of the mould cavity to form a surface of composite component 31 to be formed. The automotive shredder residue 38 is unable to permeate through the first and second later of fibres to the surface of the formed composite component and is retained substantially within the central layer of thermoplastic 37 in the formed composite component.

The thermoplastic 37 is allowed to cool before the mould cavity is opened and the formed composite component removed from the mould. In this way, the surface finish of the formed composite component 31 is determined by the finish of the surface of the mould cavity.

Claims

1. A method of manufacturing a composite component, comprising the steps of : providing a first part of a mould defining a first part of a mould cavity having a surface; laying up a first layer of fibres in the first part of the mould; introducing a quantity of thermoplastic to the first part of the mould over an uppermost surface of the first layer of fibres; laying up a second layer of fibres over the thermoplastic; providing a second part of the mould defining a second part of the mould cavity to complete the mould cavity; bringing the first and second mould parts together to compress the fibres and the thermoplastic together such that the thermoplastic permeates through the layers of fibres to the surface of the mould cavity.

2. A method according to claim 1, characterised in that the thermoplastic comprises a biodegradable thermoplastic.

3. A method according to claim 2, characterised in that the biodegradable thermoplastic includes biodegradable filler material such as miscanthus fibres.

4. A method according to any previous claim, characterised in that the thermoplastic comprises up to 30 per cent automotive shredder residue.

5. A method according to any previous claim, characterised in that the fibres comprise biodegradable fibres.

6. A method according to claim 5, characterised in that the biodegradable fibres comprise hemp, jute, or the like.

7. A method according to any previous claim, characterised in that the quantity of the thermoplastic is introduced to the mould by an extrusion apparatus.

8. A method according to any previous claim, characterised in that the layers of fibres comprise one or more sheets of woven or non woven fibres.

9. A method according to claim 8, characterised in that the first and second layers contain equal numbers of sheets of woven or non woven fibres.

10. A method of manufacturing a composite substantially as described herein with reference to and as illustrated in Figure 1 of the accompanying drawings.

11. A composite component substantially as described herein with reference to and as illustrated in either Figure 2 or Figure 3 of the accompanying drawings.