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| Severable multilayer thermoplastic film |
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| Extruder apparatus and process for compounding thermoplastic resin and fibres |
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| Method,apparatus and extrusion nozzle for producing a member from extrudable material |
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| Method of forming a fibrous web using a variable transverse webber |
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| Method of forming and bonding fluff pads |
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Manufacture of composite extrusions
| Details |
Inventors: Cook, John Edward;
Assignee: Schlegel U.K. Holdings Limited (Seacroft, GB)
Primary Examiner: Epstein; Henry F.
Assistant Examiner:
Attorney, Agent or Firm: Cumpston & Shaw
A method of forming a composite extrusion is disclosed wherein a main body portion (1) of the extrusion is first extruded from a thermosetting material, this body portion then being heated so as at least partly to cure it, the main body portion then being passed at high temperature through a further extruder where a thermoplastics material (8) is extruded onto one or more surfaces of the main body portion (1), the subsequent composite extrusion then being cooled and formed into its final shape. It is important that the combining step be undertaken at a temperatue high enough to cause the thermoplastics material to bond to the thermosetting material and while it is simplest for the thermoplastics material to be on an outer surface of the composite extrusion, it is possible for it to be located within the thermosetting material by extruding the thermosetting material in an "opened out" state and then after extruding the thermoplastics and while the extrusion is still hot, folding in edge regions of the main body to overlie the thermoplastics material and bond thereto. The thermoplastics material may be of a special color, may be embossed, and if it is located within the thermosetting material in the end product, may be stiffer than the latter. The invention also extends to the extrusions themselves. |
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DETAILED DESCRIPTION The present invention seeks to provide methods of manufacturing composite extrusions which are suitable for use as a door or boot seal in the motor industry or as a seal or window channel either in the building or motor industry, or for other purposes and which is principally formed of a vulcanised polymeric material (thermosetting/cross linked/rubber) (hereinafter called thermosetting polymeric material), which is considerably less expensive than the majority of suitable thermoplastics polymeric materials (plastics).
By virtue of the invention, it is possible to produce a wide range of extrusions relatively cheaply but which can either have surface properties of the more expensive extrusions formed of thermoplastic material and/or which can have its properties changed without having to incorporate a metal carrier in the extrusion.
According to one aspect of the present invention, we provide a method of forming a composite extrusion having a main body portion consisting at least principally of one or more thermosetting polymeric materials and at least one other portion consisting of a thermoplastic polymeric material, comprising the steps of passing said one or more thermosetting materials through an extruder to form said main body portion, at least partially curing said body portion, maintaining said body portion at an elevated temperature, passing the same, while hot, through a further extruder and extruding said thermoplastic material onto a portion thereof, thereby bonding the two materials together, and then cooling the composite extrusion, and forming it into the desired cross-sectional shape.
Also according to the present invention, we provide a composite extrusion comprising a main body formed at least principally of an extruded thermosetting polymeric material with at least one portion of the extrusion being formed of a thermoplastic polymer material bonded to the thermosetting material using a method as described above, wherein the thermoplastics material is on a surface of the composite extrusion, and of a chosen colour
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Nonmetallic Processes 
