Apparatus for producing thick slabs of thermoplastic synthetic resin

An apparatus for producing thick slabs of thermoplastic synthetic resin, comprising:

• a pair of extruders each having a broad-slot nozzle extruding a respective half-slab strand of said thermoplastic synthetic resin in a respective horizontal plane;
• respective roller assemblies each comprising a plurality of rollers and including two final rollers, all of said rollers lying in a common vertical plane, said final rollers of said assemblies defining an obstruction-free consolidation gap between them of the thickness of the slabs to be produced with said strands passing along the periphery of at least said final rollers of said assemblies into said gap wherein said strands are consolidated into said slab which is discharged in a horizontal plane, each assembly including at least one additional roller apart from the respective final roller and defining a further gap, said nozzles being each positioned to extrude the respective strand into the further gap between two rollers of the respective assembly most removed from said consolidation gap, said rollers and said nozzles being positioned to cause each strand to extend around at least one roller over an arc of 180.degree. before reaching said consolidation gap;
• and
• temperature control means for said additional rollers effective upon the respective strand, said temperature control means being effective symmetrically on opposite sides of said consolidation gap for the symmetrical cooling or heating of said strands, all of the rollers of said assemblies being of identical diameters and being disposed symmetrically with respect to said consolidation gap whereby each of said strands undergoes the same heating or cooling history as the other between the respective extruder and the gap.