Process for fabricating a multicolored sheet

In a process to produce a sheet with the aid of a multiple-duct die, and wherein said sheet includes a plurality of stripes of thermoplastic material of different respective colors, said stripes adjoining each other and being capable of being thermoformed to produce hollow volumes with the same initial decoration, with a view of avoiding creep between materials of adjacent stripes, and wherein each stripe has a predetermined thickness, comprising the steps of:

• forming said stripes of different respective colors, so as to be disposed parallel to one another;
• connecting said stripes to one another to form an intermediate layer,
• forming an outer transparent layer;
• connecting said intermediate layer to said outer transparent layer so as to cover said intermediate layer,
• forming a monochrome basic layer;
• combining the intermediate layer and the transparent layer with said basic layer so that the intermediate layer is disposed beteen the transparent layer and the monochrome basic layer, each layer having a respective prearranged thickness,
• extruding said material of different respective colors simultaneously through said multiple-duct die along a predetermined direction so that said material of different respective colors is in areas as close as possible to respective outlets of said multiple-duct die,
• selecting a first critical distance L, defined as a distance in an axial directon between one meeting point between the stripes and another meeting point of the stripes with the outer transparent layer, to have substantially a length of a maximum of 15-40 times the thickness of one of said stripes,
• selecting a second critical distance L', defined as a distance along a partly axial direction between said other meeting point of the stripes and the outer layer, and still another meeting point of the combined stripes and the outer layer with said basic layer, to have substantially a length of a maximum of 15-40 times the thickness of the combined outer and basic layers,
• whereby there is at most negligible migration of color from one stripe to an adjoining stripe especially at a separation between the stripes.