LAMINATE FOR DIMENSIONALLY STABLE FOODSTUFF CONTAINERS HAVING AN OUTER POLYMER LAYER WITH A REFLECTANCE

Abstract

The invention relates to a sheetlike composite comprising, as layers of a layer sequence, from an outer face of the sheetlike composite to an inner face of the sheetlike composite, a) an outer polymer layer comprising i) a polymer matrix, and ii) a multitude of inorganic particles; b) a carrier layer; c) a barrier layer; and d) an inner polymer layer; wherein the outer polymer layer superposed on the carrier layer is characterized by a reflectance for a reflection of light having a wavelength in a range from 600 to 800 nm in a range from 4% to 8%. The invention further relates to a container precursor and to a closed container comprising the sheetlike composite and to a method by which the sheetlike composite is obtainable, to a method by which a container is obtainable, and to a method by which a filled and closed container is obtainable, and to a use of the sheetlike composite.

Claims

1. A sheetlike composite comprising, as layers of a layer sequence, from an outer face of the sheetlike composite to an inner face of the sheetlike composite, a) an outer polymer layer comprising i) a polymer matrix, and ii) a multitude of inorganic particles; b) a carrier layer; c) a barrier layer; and d) an inner polymer layer; wherein the outer polymer layer superposed on the carrier layer is characterized by a reflectance for a reflection of light having a wavelength in a range from 600 to 800 nm according to the test method described herein in a range from 4% to 8%.

2. The sheetlike composite according to claim 1, wherein the outer polymer layer is characterized by a grammage in a range from 5 to 75 g/m.sup.2.

3. The sheetlike composite according to claim 1, wherein the outer polymer layer comprises the multitude of inorganic particles in an overall proportion in a range from 1% to 15% by weight, based on the total weight of the outer polymer layer.

4. The sheetlike composite according to claim 1, wherein the multitude of inorganic particles comprises a) a first kind of inorganic particles in a first proportion by weight, based on the total weight of the outer polymer layer, and b) a further kind of inorganic particles in a further proportion by weight, based on the total weight of the outer polymer layer, where a ratio of the first proportion by weight to the further proportion by weight is in a range from 60:1 to 1000:1.

5. The sheetlike composite according to claim 4, wherein the first proportion by weight is in a range from 1% to 15% by weight, based on the total weight of the outer polymer layer.

6. The sheetlike composite according to claim 4, wherein the further proportion by weight is in a range from 0.001% to 1% by weight, based on the total weight of the outer polymer layer.

7. A container precursor comprising the sheetlike composite (100) according to claim 1.

8. A closed container comprising the sheetlike composite according to claim 1.

9. A method comprising, as method steps, a) providing a sheetlike composite precursor comprising, as layers of a layer sequence, i) a carrier layer, and ii) a barrier layer; b) providing a first composition comprising, as constituents, i) a first amount of a polymer, and ii) a multitude of inorganic particles of a first kind; c) providing a second composition comprising, as constituents, i) a second amount of the polymer, and ii) a multitude of inorganic particles of a further kind; d) contacting the first composition and the second composition with a third amount of the polymer thereby obtaining a third composition; and e) superposing the third composition on the carrier layer, on a side of the carrier layer remote from the barrier layer, thereby obtaining an outer polymer layer.

10. A sheetlike composite obtainable by the method according to claim 9.

11. A method comprising, as method steps, A. providing the sheetlike composite according to claim 1, comprising a first longitudinal edge and a further longitudinal edge; B. folding the sheetlike composite; and C. contacting and joining the first longitudinal edge to the further longitudinal edge thereby obtaining a longitudinal seam.

12. A container precursor obtainable by the method according to claim 11.

13. A method comprising, as method steps, providing the container precursor according to claim 7; b. forming a base region of the container precursor by folding the sheetlike composite; c. closing the base region; d. filling the container precursor with a foodstuff, and e. closing the container precursor in a top region thereby obtaining a closed container.

14. A closed container obtainable by the method according to claim 13.

15. A use of the sheetlike composite according to claim 1 for production of a closed container filled with a foodstuff.

16. A use of a) a first composition comprising, as constituents, i) a first amount of a polymer, and ii) a multitude of a inorganic particles of a first kind; and b) a second composition comprising, as constituents, i) a second amount of the polymer, and ii) a multitude of inorganic particles of a further kind for production of a packaging material laminate for dimensionally stable foodstuff containers; wherein the first composition comprises the inorganic particles of the first kind in a proportion in a range from 5% to 30% by weight, based on the total weight of the first composition; wherein the second composition comprises the inorganic particles of the further kind in a proportion in a range from 0.01% to 1.5% by weight, based on the total weight of the second composition; wherein each of the inorganic particles of the first kind comprises a core comprising a silicate or a silicon oxide or both, and a shell superposed on the core, comprising an oxide of a first metal other than silicon; wherein the inorganic particles of the further kind comprise carbon in a proportion of at least 50% by weight, based on the weight of the inorganic particles of the further kind.

Description

[0205] The figures show, in schematic form and not to scale, unless stated otherwise in the description or the respective figure:

[0206] FIG. 1 a sheetlike composite according to the invention in a cross section;

[0207] FIG. 2 spectrograms;

[0208] FIG. 3 a container precursor according to the invention;

[0209] FIG. 4 a closed container according to the invention;

[0210] FIG. 5 a flow diagram of a method according to the invention;

[0211] FIG. 6 a flow diagram of a further method according to the invention; and

[0212] FIG. 7 a flow diagram of a further method according to the invention.

[0213] FIG. 1 shows a sheetlike composite 100 according to the invention in a cross section. The sheetlike composite 100 comprises, as 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 colour layer 108, an outer polymer layer 107 composed of LDPE, wherein the outer polymer layer has a reflectance in a range of 5.5% to 6.5% for light of wavelengths in a range from 600 to 800 nm at an angle of 40; a carrier layer 106 composed of paperboard; an intermediate polymer layer 105 as lamination layer, consisting of LDPE 23L430 from Ineos GmbH, Cologne; a barrier layer 104 composed of aluminium; and an inner polymer layer 103. A graph 203 of a reflection measurement of the composite according to the invention is shown in FIG. 2.

[0214] FIG. 2 shows a spectrogram 200. This comprises graphs 203 of reflection measurements on sheetlike composites 100 according to the invention and graphs 204 of reflection measurements on sheetlike composites not according to the invention. In these graphs, the abscissa axis shows the wavelength in nm and the ordinate axis the reflectance in %. It is apparent that the reflectance of the graphs 203 is between 5.5% and 7% in a wavelength range from 600 to 800 nm. The reflection measurements for the graphs 203 were conducted on a sheetlike composite 100 according to the invention, wherein the outer polymer layer 107 comprises Iriodin 123 from Merck to an extent of 5.0% by weight, based on the weight of the outer polymer layer, and carbon black to an extent of 0.08% by weight, based on the weight of the outer polymer layer. The remainder of this outer polymer layer 107 to 100% by weight consists of LDPE 23L430 from Ineos GmbH, Cologne. This outer polymer layer 107 has a grammage of 20 g/m.sup.2. In addition, the reflectance of the graphs 204 for a sheetlike composite not according to the invention in a wavelength range from 600 to 800 nm is always below 3.5%. The measurements were conducted by the Reflectance R test method described herein.

[0215] FIG. 3 shows a container precursor 300 according to the invention. The container precursor 300 comprises the sheetlike composite 100 of FIG. 1 with 4 folds 301. The sheetlike composite 100 is a blank for production of a single closed container 400. The container precursor 300 is in the form of a sleeve and comprises a longitudinal seam 302 in which a first longitudinal edge and a further longitudinal edge of the sheetlike composite 100 are sealed to one another. In addition, the container precursor 300 comprises a hole 305 in the carrier layer 106. The hole 305 is covered by the intermediate polymer layer 105, the barrier layer 104 and the inner polymer layer 103. By folding along creases 306 and joining of fold regions in a top region 303 and a base region 304 of the container precursor 300, a closed container 400 is obtainable. Such a closed container 400 is shown in FIG. 4.

[0216] FIG. 4 shows a closed container 400 according to the invention. The closed container 400 has been produced from the container precursor 300 according to FIG. 3. The closed container 400 comprises a foodstuff

401 and has 12 edges 403. In addition, the closed container 400 is joined to an opening aid 402 which covers the hole 305 on the outer face 101 of the sheetlike composite 100. Here, the opening aid 402 comprises a lid and a cutting tool connected to the lid within the interior thereof.

[0217] FIG. 5 shows a flow diagram of a method 500 according to the invention for production of a sheetlike composite 100. In a method step a) 501, a sheetlike composite precursor consisting of a carrier layer 106 composed of paperboard, an intermediate polymer layer 105 as lamination layer and a barrier layer 104 composed of aluminium is provided in the form of a roll. In a method step b) 502, a first composition comprising a first amount of a polymer, here an LDPE 23L430 from Ineos GmbH, Cologne, and a multitude of inorganic particles of a first kind, here Iriodin 111 from Merck, is provided. In a method step c) 503, a second composition, here a carbon black masterbatch FC7302 NG from Polyplast Mller, Straelen, is provided. In a method step d) 504, the first composition is mixed with the second composition and a third amount of the LDPE 23L430 from Ineos GmbH, Cologne, in an extruder thereby obtaining a third composition. In a method step e) 505, the third composition is applied on a side of the carrier layer 106 remote from the barrier layer 104 thereby obtaining an outer polymer layer 107.

[0218] FIG. 6 shows a flow diagram of a further method 600 according to the invention for production of a container precursor 300. In a method step A. 601, the sheetlike composite 100 according to FIG. 1 is provided. This comprises a first longitudinal edge and a further longitudinal edge. In a method step B. 602, the sheetlike composite 100 is folded. In a method step C. 603, the first longitudinal edge and the further longitudinal edge are pressed against one another and joined to one another by heat-sealing. Thus, a longitudinal seam 302 is obtained. According to the above description, the container precursor 300 is produced according to FIG. 3.

[0219] FIG. 7 shows a flow diagram of a further method 700 according to the invention for production of a closed container 400. In a method step a. 701, the container precursor 300 according to FIG. 3 is provided. In a method step b. 702, a base region 304 of the container precursor 300 is formed by folding the sheetlike composite 100. In a method step c. 703, the base region 304 is closed by sealing with hot air at a temperature of 300 C. In a method step d. 704, the container precursor 300 is filled with a foodstuff 401 and, in a method step e. 705, the container precursor 300 is closed by sealing in a top region 303 thereby obtaining the closed container 400. In a method step f. 706, the closed container 400 is joined to an opening aid 402.

LIST OF REFERENCE SYMBOLS

[0220] 100 sheetlike composite according to the invention [0221] 101 outer face [0222] 102 inner face [0223] 103 inner polymer layer [0224] 104 barrier layer [0225] 105 intermediate polymer layer [0226] 106 carrier layer [0227] 107 outer polymer layer [0228] 108 colour layer [0229] 200 spectrograms [0230] 201 reflectance in % [0231] 202 wavelength in nm [0232] 203 graph for a laminate according to the invention [0233] 204 graph for a laminate not according to the invention [0234] 300 container precursor according to the invention [0235] 301 fold [0236] 302 longitudinal seam [0237] 303 top region [0238] 304 base region [0239] 305 hole [0240] 306 crease [0241] 400 closed container according to the invention [0242] 401 foodstuff [0243] 402 opening aid [0244] 403 edge [0245] 500 method according to the invention for production of a sheetlike composite [0246] 501 method step a) [0247] 502 method step b) [0248] 503 method step c) [0249] 504 method step d) [0250] 505 method step e) [0251] 600 method according to the invention for production of a container precursor [0252] 601 method step A. [0253] 602 method step B. [0254] 603 method step C. [0255] 700 method according to the invention for production of a closed container [0256] 701 method step a. [0257] 702 method step b. [0258] 703 method step c. [0259] 704 method step d. [0260] 705 method step e. [0261] 706 method step f.