Method for forming a stress-free multilayer PVC sheet material
A method for forming a multilayer plastic sheet material is disclosed, where a first polymer mass is melted under pressure and is passed through an extruder head at a specified discharge rate in the form of a plastic strand in sheet form that is provided with one or more layers so that a multilayer plastic strand is formed. This is passed to two or more rolls of a finishing stand that processes the multilayer plastic strand into a sheet. After the plastic strand in sheet form leaves the extruder head, it is first passed between a top roll and a bottom roll of a roughing stand. The speed of the rolls of the finishing stand and the rolls of the roughing stand is synchronized with the discharge rate of the plastic strand in sheet form from the extruder head, so that the plastic strand is processed without stress.
1 . A multilayer sheet material manufactured via a single production process,
wherein the multilayer sheet material has an elastic modulus above 1000 N/mm 2 and a specified length and width,
wherein the multilayer sheet material comprises:
a carrier material formed from rigid PVC provided with one or more layers, wherein, after heating to 80° Celsius and cooling back to room temperature, the sheet material has expansion or shrinkage of a maximum of 0.2% of the specified length and/or width, wherein the carrier material formed from rigid PVC is provided with a co-extruded top layer of flexible PVC that is thermally fused with the rigid PVC through stress-free processing, wherein the stress-free processing comprises:
melting, under pressure, a first polymer mass comprising the rigid PVC and a second polymer mass comprising the flexible PVC,
passing the first polymer mass and the second polymer masses through an extruder head at a pre-determined discharge rate in the form of a multilayer plastic strand in sheet form, wherein the top layer of the multilayer plastic strand is formed by the second polymer mass, and
synchronizing a speed of rolls of a calendaring device with the pre-determined discharge rate of the multilayer plastic strand so that the multilayer plastic strand is processed without stress, and
a decorative effect applied by direct printing on the flexible PVC or on the rigid PVC before applying an ultraviolet (UV) varnish coat.
2 . The multilayer sheet material of claim 1 , wherein a transparent PVC wearlayer of between 0.1 and 1.0 mm is provided on top of the decorative layer.
3 . The multilayer sheet material of claim 2 , wherein a wooden or stone embossing structure is applied in the wearlayer.
4 . The multilayer sheet material of claim 3 , wherein the carrier material is further provided with a bottom layer that is fastened to the carrier material with an adhesive.
5 . The multilayer sheet material of claim 1 , wherein the carrier material is provided with small air bubbles reducing a specific weight of the sheet material.
6 . The multilayer sheet material of claim 1 , wherein the method further comprises:
passing the multilayer plastic strand to two or more rolls of the calendering device; and
processing the multilayer plastic strand into a sheet of defined thickness.
7 . The multilayer sheet material of claim 6 , wherein the method further comprises:
leading away the sheet of defined thickness via a transport device to a sawing device to be cut to a desired length.
8 . The multilayer sheet material of claim 7 , wherein the method further comprises:
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.
9 . The multilayer sheet material of claim 8 , wherein a 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.
10 . A multilayer sheet material manufactured via a single production process,
wherein the multilayer sheet material has an elastic modulus above 1000 N/mm 2 and a specified length and width,
wherein the multilayer sheet material comprises:
a carrier material formed from rigid PVC provided with one or more layers, wherein, after heating to 80° Celsius and cooling back to room temperature, the sheet material has expansion or shrinkage of a maximum of 0.2% of the specified length and/or width, wherein the carrier material formed from rigid PVC is provided with a co-extruded top layer of flexible PVC that is thermally fused with the rigid PVC through stress-free processing, wherein the stress-free processing comprises:
melting, under pressure, a first polymer mass comprising the rigid PVC and a second polymer mass comprising the flexible PVC,
passing the first polymer mass and the second polymer masses through an extruder head at a pre-determined discharge rate in the form of a multilayer plastic strand in sheet form, wherein the top layer of the multilayer plastic strand is formed by the second polymer mass, and
synchronizing a speed of rolls of a calendaring device with the pre-determined discharge rate of the multilayer plastic strand so that the multilayer plastic strand is processed without stress.
11 . The multilayer sheet material of claim 10 , wherein the extruder head is comprised in at least one extruder connected to a multilayer T-die.
12 . The multilayer sheet material of claim 11 , wherein the method further comprises:
passing the multilayer plastic strand to two or more rolls of the calendering device; and
processing the multilayer plastic strand into a sheet of defined thickness.
13 . The multilayer sheet material of claim 12 , wherein the method further comprises:
leading away the sheet of defined thickness via a transport device to a sawing device to be cut to a desired length.
14 . The multilayer sheet material of claim 13 , wherein the method further comprises:
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.
15 . The multilayer sheet material of claim 14 , wherein a 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.
16 . The multilayer sheet material of claim 15 , wherein the method further comprises:
providing the sheet material with a decorative effect by direct printing on the flexible PVC or on the rigid PVC before applying an UV varnish coat.