FLAT COMPOSITE FOR PRODUCING DIMENSIONALLY STABLE FOOD CONTAINERS, CONTAINING A POLYMER LAYER WITH A POLYESTER AND AN ISOTROPIC MODULUS OF ELASTICITY

Abstract

The invention relates to a sheetlike composite comprising, as mutually superposed layers in a direction from an outer face of the sheetlike composite to an inner face of the sheetlike composite, a) a carrier layer, and b) a barrier layer;
wherein the sheetlike composite additionally comprises a polymer layer P, wherein the polymer layer P a. comprises a polyester, b. extends two-dimensionally within a layer plane, c. has a first modulus of elasticity in a first layer direction which lies in the layer plane, and d. has a further modulus of elasticity in a further layer direction which lies in the layer plane and is perpendicular to the first layer direction;
wherein a ratio of the first modulus of elasticity to the further modulus of elasticity is within a range from 0.81 to 1.19. The invention further relates to methods of producing a sheetlike composite, a container precursor and a container, and to the aforementioned method products; to a container precursor and a container each comprising at least one sheetlike region of the sheetlike composite; and to uses of the sheetlike composite, of an extruder, of a chain modifier, of a mixture, of a base polymer, and of polyesters.

Claims

1. A sheetlike composite comprising, as mutually superposed layers, in a direction from an outer face of the sheetlike composite to an inner face of the sheetlike composite, a) a carrier layer, and b) a barrier layer, wherein the sheetlike composite additionally comprises a polymer layer P, wherein the polymer layer P a. comprises a polyester, b. extends two-dimensionally within a layer plane, c. has a first modulus of elasticity in a first layer direction which lies in the layer plane, and d. has a further modulus of elasticity in a further layer direction which lies in the layer plane and is perpendicular to the first layer direction; wherein a ratio of the first modulus of elasticity to the further modulus of elasticity is within a range from 0.81 to 1.19.

2. The sheetlike composite as claimed in claim 1, wherein the polymer layer P has a melting temperature of more than 145° C.

3. The sheetlike composite as claimed in claim 1, wherein the polymer layer P has a density of more than 1.1 g/cm.sup.3.

4. A method comprising, as method steps, a) providing i) a sheetlike composite precursor comprising a carrier layer, and ii) a polymer composition P comprising a polyester; and b) superimposing the carrier layer with the polymer composition P, thereby obtaining a polymer layer P superimposing the carrier layer; wherein the polymer layer P a. extends two-dimensionally within a layer plane, b. has a first modulus of elasticity in a first layer direction which lies in the layer plane, and c. has a further modulus of elasticity in a further layer direction which lies in the layer plane and is perpendicular to the first layer direction, wherein a ratio of the first modulus of elasticity to the further modulus of elasticity is within a range from 0.81 to 1.19.

5. A method comprising, as method steps, a) providing i) a sheetlike composite precursor comprising a carrier layer, and ii) a polymer composition P comprising a polyester; and b) superimposing the carrier layer with the polymer composition P, thereby obtaining a polymer layer P superimposing the carrier layer; wherein the polymer composition P is liquid in the superimposing operation in method step b).

6. A sheetlike composite obtainable by the method as claimed in claim 4.

7. A container precursor comprising at least one sheetlike region of the sheetlike composite as claimed in claim 1.

8. A container comprising at least one sheetlike region of the sheetlike composite as claimed in claim 1.

9. A method comprising, as method steps, a. providing at least one sheetlike region of the sheetlike composite as claimed in claim 1, said at least one sheetlike region comprising a first longitudinal rim and a further longitudinal rim; b. folding the at least one sheetlike region; and c. contacting and joining the first longitudinal rim to the further longitudinal rim, thereby obtaining a longitudinal seam.

10. A container precursor obtainable by the method as claimed in claim 9.

11. A method comprising, as method steps: A. providing the container precursor as claimed in claim 7; B. forming a base region of the container precursor by folding the sheetlike region; C. closing the base region; D. filling the container precursor with a food or drink product; and E. closing the container precursor in a top region, thereby obtaining a closed container.

12. A closed container obtainable by the method as claimed in claim 11.

13. A use of the sheetlike composite as claimed in claim 1 for production of a food or drink product container.

14. A use of an extruder for reacting of a base polymer with a chain modifier, thereby obtaining a polymer P and for obtaining a sheetlike composite for a food or drink product container by means of melt extrusion coating with the polymer P.

15. A use of a chain modifier for producing a sheetlike composite for a food or drink product container.

16. A use of a mixture comprising a base polymer and a chain modifier for producing a sheetlike composite for a food or drink product container.

17. A use of a base polymer for producing a sheetlike composite for a food or drink product container by means of reacting the base polymer with a chain modifier.

18. A use of a polyester for producing a sheetlike composite for a food or drink product container by means of melt extrusion coating with the polyester.

19. A use of a polyester for producing a sheetlike composite for a food or drink product container, wherein the sheetlike composite comprises a polymer layer P, comprising the polyester, wherein the polymer layer P a. extends two-dimensionally within a layer plane, b. has a first modulus of elasticity in a first layer direction which lies in the layer plane, and c. has a further modulus of elasticity in a further layer direction which lies in the layer plane and is perpendicular to the first layer direction, wherein a ratio of the first modulus of elasticity to the further modulus of elasticity is within a range from 0.81 to 1.19.

Description

[0301] The figures respectively show, in schematic form and not to scale, unless stated otherwise in the description or the respective figure:

[0302] FIG. 1 a schematic diagram of a section of a sheetlike composite of the invention in cross section;

[0303] FIG. 2 a schematic diagram of a section of a further sheetlike composite of the invention in cross section;

[0304] FIG. 3 a flow diagram of a method of the invention for producing a sheetlike composite;

[0305] FIG. 4 a flow diagram of a method of the invention for producing a container precursor;

[0306] FIG. 5 a schematic diagram of a container precursor of the invention;

[0307] FIG. 6 a flow diagram of a method of the invention for producing a closed container;

[0308] FIG. 7 a schematic diagram of a closed container of the invention; and

[0309] FIG. 8 a diagram of the dependence of the shear viscosity of the polymer layer P on the shear frequency for the polymer layers P of examples 6, 14 and 22, and comparative examples 8, 19 and 30.

[0310] FIG. 1 shows a schematic diagram of a section of a sheetlike composite 100 of the invention in cross section. The sheetlike composite 100 consists of the following layers of a layer sequence in the direction from an outer face 101 of the sheetlike composite 100 to an inner face 102 of the sheetlike composite 100: an outer polymer layer 103, a carrier layer 104, a barrier layer 105 and an inner polymer layer 106. The carrier layer 104 is a cardboard layer identified as Stora Enso Natura T Duplex double-coated (Scott bond value 200 J/m.sup.2, residual moisture content 7.5%). The barrier layer 105 consists of EVOH, available as EVAL L171B from Kuraray, Dusseldorf, Germany. The outer polymer layer 103 and/or the inner polymer layer 106 may be the polymer layer P as described herein. Each polymer layer P comprises a polyester. In addition, each polymer layer P extends two-dimensionally in a respective layer plane and has a first modulus of elasticity in a first layer direction lying in the layer plane, and a further modulus of elasticity in a further layer direction lying in the layer plane. In each case, the first layer direction and corresponding further layer direction are perpendicular to one another. Moreover, a ratio of the first modulus of elasticity to the further modulus of elasticity is within a range from 0.96 to 1.04. If the outer polymer layer 103 is not a polymer layer P, it consists of LDPE 19N430 from Ineos GmbH, Cologne, Germany. If the inner polymer layer 106 is not a polymer layer P, it consists of a blend of 65% by weight of LDPE 19N430 from Ineos GmbH, Cologne, Germany and 35% by weight of Eltex 1315 AZ from Ineos GmbH, Cologne, Germany.

[0311] FIG. 2 shows a schematic diagram of a section of a further sheetlike composite 100 of the invention in cross section. The sheetlike composite 100 consists of the following layers in a layer sequence in a direction from an outer face 101 of the sheetlike composite 100 to an inner face 102 of the sheetlike composite 100: an ink application 201 which forms a four-colored decoration, an outer polymer layer 103, a carrier layer 104, a polymer interlayer 202, a first adhesion promoter layer 203, a barrier layer 105, a second adhesion promoter layer 204 and an inner polymer layer 106. The carrier layer 104 is a cardboard layer identified as Stora Enso Natura T Duplex double-coated (Scott bond value 200 J/m.sup.2, residual moisture content 7.5%). The barrier layer 105 is an aluminum foil having the EN AW 8079 name from Hydro Aluminium Deutschland GmbH. Any or else two or more selected from the group consisting of the outer polymer layer 103, the polymer interlayer 202 and the inner polymer layer 106 may be configured as polymer layer P described herein. The polymer layer P here consists of a polyester which is obtained by treating one of the base polymers specified in table 1 with the chain modifier specified for that purpose. If the outer polymer layer 103 is not a polymer layer P, it consists of LDPE 19N430 from Ineos GmbH, Cologne, Germany. The polymer interlayer 202, if it is not a polymer layer P, consists of LDPE 19N430 from Ineos GmbH, Cologne, Germany. The first adhesion promoter layer 203 and the second polymer layer 204 each consist of EAA Escor 6000 from Exxon Mobil Corporation. If the inner polymer layer 106 is not a polymer layer P, it consists, in a direction from the barrier layer 106 to the inner face 102, of the following three sublayers: a first sublayer composed of 75% by weight of HDPE and 25% by weight of LDPE, based in each case on the total weight of the first sublayer, a second sublayer composed of 100% by weight of LDPE based on the total weight of the second sublayer and a third sublayer composed of a polymer blend, where the polymer blend consists to an extent of 30% by weight of an mPE and to an extent of 70% by weight of an LDPE, based in each case on the total weight of the third sublayer.

[0312] FIG. 3 shows a flow diagram of a method 300 of the invention for production of a sheetlike composite 100. In a method step a) 301, a sheetlike composite precursor is provided. This comprises a carrier layer 104. Moreover, a polymer composition P comprising a polyester is provided. In a method step b) 302, the carrier layer 104 is superimposed with the polymer composition P by means of layer extrusion. Accordingly, the polymer composition P is liquid in the superimposing operation. The extrusion coating affords a polymer layer P from the polymer composition P that superimposes the carrier layer 104. This polymer layer P extends two-dimensionally in a layer plane. In one direction lying in the layer plane, in which layer extrusion was effected (machine direction), the polymer layer P has a first modulus of elasticity. In a further layer direction likewise lying within the layer plane, perpendicular to the machine direction, the polymer layer P has a further modulus of elasticity. A ratio of the first modulus of elasticity to the further modulus of elasticity is 1.02.

[0313] FIG. 4 shows a flow diagram of a method 400 of the invention for producing a container precursor 500. In a method step a. 401, a blank of the sheetlike composite 100 of FIG. 2 is provided. This blank comprises a first longitudinal rim and a further longitudinal rim. In a method step b. 402, the blank is folded. In a method step c. 403, the first longitudinal rim and the further longitudinal rim are pressed against one another and joined to one another by heat-sealing. Thus, a longitudinal seam 502 is obtained. According to the above description, the container precursor 500 according to FIG. 5 is produced.

[0314] FIG. 5 shows a schematic diagram of a container precursor 500 of the invention. The container precursor 500 comprises a blank of the sheetlike composite 100 of FIG. 1 with 4 longitudinal folds 501, each of which forms a longitudinal edge 501. In the container precursor 500, the outer face 101 of the sheetlike composite 100 faces outward. The container precursor 500 is in the form of a shell and comprises a longitudinal seam 502 in which a first longitudinal rim and a further longitudinal rim of the sheetlike composite 100 are sealed to one another. In addition, the container precursor 500 comprises a hole 505 in the carrier layer 104. The hole 505 is covered by the outer polymer layer 103 (not shown), the polymer interlayer 202 (not shown), the barrier layer 105 and the inner polymer layer 106 (not shown) as hole-covering layers. By folding along grooves 506 and joining of fold regions in a top region 503 and a base region 504 of the container precursor 500, a closed container 700 is obtainable. Such a closed container 700 is shown in FIG. 7.

[0315] FIG. 6 shows a flow diagram of a method 600 of the invention for producing a closed container 700. In a method step A. 601, the container precursor 500 according to FIG. 5 is provided. In a method step B. 602, a base region 504 of the container precursor 500 is formed by folding the sheetlike composite 100. In a method step C. 603, the base region 504 is closed by sealing with hot air at a temperature of 300° C. In a method step D. 604, the container precursor 500 is filled with a food or drink product 701 and, in a method step E. 605, the container precursor 500 is closed by sealing in a top region 503 to obtain the closed container 700 of FIG. 7. In a method step F. 606, the closed container 700 is joined to an opening aid 702.

[0316] FIG. 7 shows a schematic diagram of a closed container 700 of the invention. The closed container 700 has been produced from the container precursor 500 according to FIG. 5. The closed container 700 comprises a food or drink product 701 and has 12 edges 501. In addition, the closed container 700 is connected to a lid comprising an opening aid 702 which covers the hole 505 on the outer face 101 of the sheetlike composite 100. Here, the lid 702 comprises a cutting tool as opening aid in its interior.

[0317] FIG. 8 shows a diagram of the dependence of the shear viscosity in Pa.Math.s 802 of the polymer layer P on the shear frequency in rad/s 801 for the polymer layers P of examples 6, 14 and 22, and comparative examples 8, 19 and 30. What are shown are test results obtained by the test method described herein for Globio® BCB80, FKUR 807, treated as described above for the examples, and test results for untreated Globio® BCB80, FKUR 808. For the measurement curve 807 of the polymer layer P of the invention composed of treated Globio® BCB80, the diagram additionally shows the first shear viscosity 805 at the first shear frequency 803 and the further shear viscosity 806 at the further shear frequency 804. It is clearly apparent that the curve 807 shows distinctly greater shear thinning than curve 808 in the range from the first shear frequency 803 of 0.1 rad/s to the further shear frequency 804 of 100 rad/s. In addition, the curve 807 in this region is a non-linear, strictly monotonously decreasing curve of decreasing slope.

LIST OF REFERENCE NUMERALS

[0318] 100 Sheetlike composite of the invention [0319] 101 Outer face [0320] 102 Inner face [0321] 103 Outer polymer layer [0322] 104 Carrier layer [0323] 105 Barrier layer [0324] 106 Inner polymer layer [0325] 201 Ink application [0326] 202 Polymer interlayer [0327] 203 First adhesion promoter layer [0328] 204 Second adhesion promoter layer [0329] 300 Method of the invention for production of a sheetlike composite [0330] 301 Method step a) [0331] 302 Method step b) [0332] 400 Method of the invention for producing a container precursor [0333] 401 Method step a. [0334] 402 Method step b. [0335] 403 Method step c. [0336] 500 Container precursor of the invention [0337] 501 Longitudinal fold/edge [0338] 502 Longitudinal seam [0339] 503 Top region [0340] 504 Base region [0341] 505 Hole [0342] 506 Groove [0343] 600 Method of the invention for producing a closed container [0344] 601 Method step A. [0345] 602 Method step B. [0346] 603 Method step C. [0347] 604 Method step D. [0348] 605 Method step E. [0349] 606 Method step F. [0350] 700 Container of the invention [0351] 701 Food or drink product [0352] 702 Lid with opening aid [0353] 801 Shear frequency in rad/s [0354] 802 Shear viscosity in Pa.Math.s [0355] 803 First shear frequency [0356] 804 Further shear frequency [0357] 805 First shear viscosity [0358] 806 Further shear viscosity [0359] 807 Measurement results for treated Globio® BCB80, FKUR [0360] 808 Measurement results for untreated Globio® BCB80, FKUR