Method for forming a stress-free multilayer PVC sheet material

A method for forming a multilayer plastic sheet material for floor and/or wall panels, comprising:

• melting, under pressure, a first polymer mass comprising a rigid PVC and a second polymer mass comprising a flexible PVC,
• passing the first polymer mass through a first extruder and passing the second polymer mass through a second extruder, both the first and the second extruders connected to a multilayer T-die, wherein the passing of both the first and the second polymer masses is at a specified discharge rate in the form of a multilayer plastic strand in sheet form, the top layer of which is formed by the second polymer mass,
• passing the multilayer plastic strand to two or more rolls of a calendering device and processing the multilayer plastic strand into a sheet of defined thickness,
• leading away the sheet of defined thickness via a transport device to a sawing device to be cut to the desired length,
• after the plastic strand in sheet form leaves the extruder head, passing the plastic strand in sheet form between a top roll and a bottom roll of a pre calendering unit,
• wherein the speed of the rolls of the calendering device and the rolls of the pre calendering unit is synchronized with the discharge rate of the plastic strand in sheet form from the extruder head,
• further comprising providing the plastic material with a decorative effect by a) applying a decorative layer of PVC on the multilayer plastic strand before the multilayer plastic strand in sheet form is passed between the top roll and the bottom roll of the pre calendaring unit, or b) by applying a transparent wear layer with a thickness of between 0.1 and 1 mm, which is provided with a print, on the multilayer plastic strand before the multilayer plastic strand in sheet form is passed between the top roll and the bottom roll of the pre calendaring unit.