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US 12,194,714 B2Granted
Method for producing a multilayer composite film, multilayer composite film, and use thereof
AssigneeKuhne Anlagenbau GmbH
InventorJürgen Michael Schiffmann
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Abstract
A method of manufacturing a coextruded and/or laminated and biaxially oriented composite film and a resulting multilayered film which has improved processability and/or improved recyclability. For this purpose, the method and multilayered film provides a novel combination of the density of various layer components of the composite film and certain manufacturing parameters such as the stretching factors, relaxation factors, relaxation temperatures, and residual stretching factors.
Claims20
A method for manufacturing a multilayered composite film, the method comprising the following steps:
- a step of co-extruding and/or laminating at least three layers (a), (b) and (c) of which:
- the layer (a) forms an outward surface of the composite film;
- the layer (c) forms a surface of the composite film facing or coming in contact with a good to be packaged;
- and
- the layer (b) is disposed between the layer (a) and the layer (c);
- the layer (b) includes a single layer or a plurality of layers (b);
- a step of stretching the co-extruded or laminated composite film;
- and
- a step of relaxing the stretched composite film;
- wherein the stretching is bi-axial;
- wherein a stretch factor in a machine direction (MD) is at least 2.0;
- wherein a stretch factor in a transversal direction (TD) is at least 2.0;
- wherein a sum of the stretch factor in the machine direction (MD) and the stretch factor in the transversal direction (TD) is at least 5.0;
- wherein the composite film has a temperature of 70 to 130° C. during stretching;
- wherein a relaxation factor in the machine direction (MD) is more than 0.00;
- wherein a relaxation factor in the transversal direction (TD) is more than 0.00;
- wherein a sum of the relaxation factor in the machine direction (MD) and the relaxation factor in the transversal direction (TD) is at least 0.05;
- wherein the composite film has a temperature of 60 to 180° C. during relaxation;
- wherein a dwell time during relaxation is at least 2 seconds;
- wherein the dwell time during relaxation is at most 30 seconds;
- wherein a residual stretch factor in the machine direction (MD) is at most 5.0;
- wherein a residual stretch factor in the transversal direction (TD) is at most 5.0;
- wherein the layer (a) comprises ethylene-vinyl alcohol copolymer (EVOH) having a density of at least 1.12 g/cm3;
- wherein the layer (b) or the plurality of layers (b) comprises of a thermoplastic resin having a density greater than 1.00 g/cm3;
- and
- wherein the layer (c) comprises a thermoplastic resin having a density of less than 0.95 g/cm3.
23 more elements
A method for manufacturing a multilayered composite film, the method comprising the following steps:
- a step of co-extruding and/or laminating at least four layers (a), (b), (d) and (c) of which:
- the layer (a) forms an outward surface of the composite film;
- the layer (c) forms a surface of the composite film facing or coming in contact with a good to be packaged;
- the layer (b) is disposed between the layer (a) and the layer (c);
- and
- the layer (d) is disposed between the layer (a) and the layer (c);
- the layer (b) includes a single layer or a plurality of layers (b);
- the layer (d) includes a single layer or a plurality of layers (d);
- a step of stretching the co-extruded or laminated composite film;
- and
- a step of relaxing the stretched composite film;
- wherein the stretching is bi-axial;
- wherein a stretch factor in a machine direction (MD) is at least 2.0;
- wherein a stretch factor in a transversal direction (TD) is at least 2.0;
- wherein a sum of the stretch factor in the machine direction (MD) and the stretch factor in the transversal direction (TD) is at least 5.0;
- wherein the composite film has a temperature of 70 to 130° C. during stretching;
- wherein a relaxation factor in the machine direction (MD) is more than 0.00;
- wherein a relaxation factor in the transversal direction (TD) is more than 0.00;
- wherein a sum of the relaxation factor in the machine direction (MD) and of the relaxation factor in the transversal direction (TD) is at least 0.05;
- wherein the composite film has a temperature of 60 to 180° C. during relaxation;
- wherein a dwell time during relaxation is at least 2 seconds;
- wherein the dwell time during relaxation is at most 30 seconds;
- wherein a residual stretch factor in the machine direction (MD) is at most 5.0;
- wherein a residual stretch factor in the transversal direction (TD) is at most 5.0;
- wherein the layer (a) comprises ethylene-vinyl alcohol copolymer (EVOH) having a density of at least 1.12 g/cm3;
- wherein the layer (d) or the plurality of layers (d) each comprises a thermoplastic resin having a density of less than 1.00 g/cm3;
- wherein the layer (b) or the plurality of layers (b) comprises a thermoplastic resin having a density greater than 1.00 g/cm3;
- and
- wherein the layer (c) comprises a thermoplastic resin having a density of less than 0.95 g/cm3.
26 more elements
Dependencies are inferred from the claim text.