1. Field of the Invention
The invention relates to a process for manufacturing a plastic composite profile, of any cross section, having an outer layer or skin made of a first material and at least one inner layer made of a different material suitable for adhering to the skin, according to which process the materials of the profile are coextruded.
The invention relates especially to the manufacture of profiles with a prismatic surface, having differently oriented plane faces joined together in arcs of low radius of curvature, the outline of the cross section of the profile having the shape of a convex, or concave, or convex and concave polygon. The reader is reminded that a polygon is a figure formed by an ordered sequence of segments or sides, each of which has one end common with the previous one and with the following one.
The invention relates more particularly, but not exclusively, to the manufacture of profiles used in the construction industry, for example for door frames, window frames, partition elements and wall coverings.
2. Description of Related Art
A process of this kind is known from document FR-A-2,470,672. This process uses a complex coextrusion head comprising two extrusion nozzles, the cross sections of which have shapes identical or similar to those of the desired sections for the various materials in the completed profile.
The coextrusion head is specific to a particular profile. It is therefore necessary to have as many coextrusion heads as types of profiles to be manufactured.
Now, a coextrusion head comprising at least two nozzles, and sometimes more, for the inlet of different materials is expensive. This entails considerable investment when there are many different sections of profiles to be produced.
Moreover, it is known to manufacture plastic tubes with a composite wall, as taught for example by FR-A-2,455,972, but this document does not provide for the manufacture of profiles with a prismatic surface and with a composite wall.