(19) United States
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`(12) Patent Application Publication (10) Pub. No.: US 2008/0020162 A1
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`Fackler et al.
`(43) Pub. Date:
`Jan. 24, 2008
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`US 20080020 1 62A1
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`(54) PACKAGING MATERIAL COMPRISING A
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`FOAMED POLYOLEFIN LAYER
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`(75)
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`Inventors:
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`Tobias Fackler, Bad Gronenbach
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`Walter Bernig, Durach
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`Bernard Dujardin, Brussel
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`Correspondence Address:
`NORRIS, MCLAUGHLIN & MARCUS, p_A_
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`875 THIRD AVE, 18TH FLOOR
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`NEW YORK, NY 10022
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`(73) Assigneez
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`CFS Kempten Gmbh, Kempten
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`(DE)
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`A 1. N .:
`21
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`(22) PCT Filed.
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`10/577 090
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`Oct 25’ 2004
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`(86) PCT No‘;
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`PCT/E1304/12029
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`§ 371 (c)(1),
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`(2), (4) Date;
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`Jan, 19, 2007
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`(30)
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`Foreign Application Priority Data
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`Oct. 27, 2003
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`(DE) ............................... .. 103502378
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`Publication Classification
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`(51)
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`Int CL
`(2006.01)
`B32B 5/18
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`B65-D 65/40
`(200601)
`(52) U.S. Cl.
`...... .. 428/36.5; 426/415; 428/158; 428/159
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`(57)
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`ABSTRACT
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`The invention relates to a multilayer film comprising the
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`following sequence of layers. A) a polyolefin foam base
`layer containing 0.5 to 25 percent by weight of at least one
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`nucleation agent; B) a layer based on at least one polyolefin
`of foam layer A); C) an optional polyolefin-based connect-
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`mg layer; D) an optional bonding layer; E) an. optional
`gas-tight and/or odor-proof barrier layer; F) a bonding layer;
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`G) an optionally sealable and/or peelable surface layer. The
`total thickness of layers A) and B) ranges between 0.5 and
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`2 mm while the thickness of layer B) ranges between one
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`sixth and one half of the thickness of layer A).
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`PAGE 1 OF 5
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`BOREALIS EXHIBIT 1009
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`BOREALIS EXHIBIT 1009
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`PAGE 1 OF 5
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`US 2008/0020162 A1
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`Jan. 24, 2008
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`PACKAGING MATERIAL COMPRISING A
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`FOAMED POLYOLEFIN LAYER
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`[0001] The invention is concerned with the packaging
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`industry and relates to a packaging material which has a
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`foamed polyolefin layer as an outer layer, which comprises
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`on the surfaces thereof further layers and to packaging
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`produced therefrom.
`Packaging materials with a foam layer of for
`[0002]
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`example polypropylene in the form of virtually continuous,
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`reeled webs are used for the production of thermoformed,
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`self-supporting packages such as for example trays for
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`packaging foodstulfs. To this end, such packaging materials
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`may be converted into packages on “FFS machines” (form-
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`fill-seal machines), wherein the packaging material in web
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`form is fed into a forming apparatus, is shaped therein into
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`a web of trays, the material to be packaged is introduced into
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`the trays, which are closed by heat-sealing with a preferably
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`transparent film. The closed trays may then be separated
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`from one another.
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`[0003]
`In known packaging materials, the layer of foamed
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`polyolefin is provided with further layers on at least one side
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`of its surface. Depending on the composition and thickness
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`of these layers, they may increase the rigidity of the pack-
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`aging material and/or serve as a protection for the foam
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`surface and/or as a gas and/or aroma barrier and/or as a
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`surface layer for heat-sealing a filled packaging tray with a
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`preferably transparent lidding film.
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`Packaging materials comprising a layer of foamed
`[0004]
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`polypropylene for the production of packaging trays by
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`thermoforming are described for example in EP-A-0 570
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`222. These materials comprise a foam layer and a multilayer
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`composite film, which may optionally contain a barrier layer
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`which makes the packaging material gas- and aroma-tight.
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`This multilayer packaging material does not always exhibit
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`the desired properties for self-supporting packages.
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`[0005] EP-B-1 117 526 discloses complementing the foam
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`layer with a compact layer of a polyolefin of the foam layer
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`while maintaining a specific thickness ratio of these two
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`layers to one another in order to improve the self-supporting
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`properties of packages produced from this packaging mate-
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`rial without increasing the thickness of the packaging mate-
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`rial.
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`[0006] Although this packaging material may very readily
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`be converted into packages, for example by thermoforming,
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`there is a requirement due to ever higher packaging machin-
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`ery running speeds to improve the packaging material in
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`such a manner that it permits higher production speeds, i.e.
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`shorter cycle times, without, for example, irregularities in
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`the wall thickness of the packaging container consequently
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`arising and without the mechanical strength or rigidity and
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`thus the self-supporting properties of the packaging con-
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`tainer being impaired.
`[0007]
`Said object is achieved according to the invention
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`by providing a multilayered film which comprises the fol-
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`lowing sequence of layers:
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`[0008] A) a base layer of polyolefin foam containing 0.5
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`to 25 wt. %, relative to the total weight of the base layer,
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`of at least one nucleating agent,
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`[0009] B) a layer based on at least one polyolefin of the
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`foam layer A),
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`PAGE 2 OF 5
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`[0010] C) optionally a bonding layer based on a polyole-
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`fin, which is preferably based on the particular monomer
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`which is the main monomer of the polyolefin of foam
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`layer A),
`[0011] D) optionally a coupling agent layer,
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`[0012] E) optionally a gas- and/or aroma-barrier layer,
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`F) a coupling agent layer,
`[0013]
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`[0014] G) an optionally heat-sealable and/or peelable sur-
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`face layer,
`wherein the total thickness of layers A) and B) is in the range
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`from 0.5 to 2 mm and the thickness of layer B) is in the range
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`from 1/5 to 1/2 of the thickness of layer A).
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`[0015] The total thickness of layers A) and B) is preferably
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`in the range from 0.6 to 1.4 mm and the thickness of layer
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`B) is in the range from 1/5 to 1/3 of the thickness of layer A).
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`[0016] The foam layer A) consists of at least one foamed
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`polyolefin. Foamed propylene homo- and/or copolymers are
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`here particularly suitable for the production of packages,
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`such as for example packaging trays for packaging food-
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`stuffs, as these materials exhibit self-supporting properties
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`even when they are of low thickness and low density. It is
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`also possible to use blends of polyolefins to produce the
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`foam layer. A blend of polypropylene having long-chain
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`branching and thus elevated melt strength and a propylene-
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`ethylene copolymer, such as for example a heterophase
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`propylene-ethylene block copolymer is in particular suit-
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`able. In particular, a blend of a polypropylene with long-
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`chain branching and a melt flow index (MFI) in the range
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`from 1.4 to 4.2 g/10 min (2.16 kg, 230° C. measured
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`according to ISO 1133) and a heterophase propylene-ethyl-
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`ene block copolymer in a mixing ratio of 1:1 is suitable.
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`[0017]
`Foaming of the polyolefin of layer A) may proceed
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`by the addition of solid,
`liquid and/or gaseous blowing
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`agents, which are added to the polyolefin in conventional
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`quantities, preferably in an amount of 0.5 to 3 wt. %.
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`Reference is here made to the disclosure in EP-A-0 570 222,
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`which is hereby introduced as a reference and deemed to be
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`part of the present disclosure.
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`[0018] The foam layer A) contains 0.5 to 25 wt. %,
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`preferably 2.1 to 20 wt. %, particularly preferably more than
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`2.5 to 15 wt. %, relative to the total weight the foam layer
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`A), of at least one nucleating agent. The nucleating agent is
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`preferably finely divided with an average particle size in the
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`range from 4 to 20 pm.
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`[0019]
`Suitable nucleating agents are any known solid
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`nucleating agents, preferably synthetic or natural inorganic
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`compounds. At least one nucleating agent selected from
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`among the group comprising talcum, titanium dioxide, sili-
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`con dioxide, calcium carbonate, magnesium silicate, alu-
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`minium silicate, calcium phosphate and montmorillonite is
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`particularly preferably used. Talcum is very particularly
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`preferably used.
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`[0020] The nucleating agent is added to the polymer from
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`which the foam layer is to be produced, preferably in the
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`form of a masterbatch which contains 30 to 60 wt. % of
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`nucleating agent in the polymer, and is largely homoge-
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`neously dispersed therein prior to foaming.
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`[0021] The foam layer A) obtained therefrom are distin-
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`guished by an elevated number of cells with relatively small
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`size deviations. The cell count is preferably greater than or
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`equal to 250 cells/mm3, particularly preferably greater than
`or equal to 300 cells/mm3 up to 600 cells/mm3, the size
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`variations of the cells being in the range of 115%, preferably
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`PAGE 2 OF 5
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`US 2008/0020162 A1
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`Jan. 24, 2008
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`110%. The density of the foam layer A) is preferably in the
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`range from 0.35 to 0.55 g/cm3.
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`[0022] The density and cell count may moreover be varied
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`by process parameters, such as for example extrusion tem-
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`perature or other process parameters, during the preferred
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`production of the foam layer by extrusion and expansion.
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`[0023] Layer B) of compact polyolefin is substantially
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`based on at least one polyolefin of the foamed base layer A).
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`If this base layer consists of foamed polypropylene or a
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`foamed blend of polypropylene and propylene-ethylene
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`copolymer, the compact polyolefin layer B) is preferably
`based on polypropylene or a propylene-ethylene copolymer.
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`A heterophase propylene-ethylene block copolymer is par-
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`ticularly preferred. The melt flow index (MFI) of the poly-
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`olefins used to produce layer B) is preferably in the range
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`from 1.8 to 5.5 g/ 10 min measured as stated above. The
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`thickness of layer B) amounts to 1/5 to 1/2, particularly
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`preferably to 1/5 to 1/3 of the thickness of layer A).
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`[0024] Layer C) is preferably present, if layers D) to G)
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`are prefabricated by coextrusion, preferably by blown film
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`coextrusion, and are to be bonded with the other layers.
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`Layer C) is based on a polyolefin, which has preferably been
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`produced from a monomer which is also the main monomer
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`of the polyolefins of which foam layer A) consists. Accord-
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`ingly, if layer A) consists of a foamed polypropylene and
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`optionally a propylene-ethylene copolymer, layer C) may
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`consist of polypropylene which optionally comprises grafted
`maleic anhydride units. Copolymers of ethylene-vinyl
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`acetate may also be used as a further component. The
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`thickness of layer C) is preferably 5 to 25 um, particularly
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`preferably 8 to 15 pm.
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`If the multilayer films according to the invention
`[0025]
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`are to exhibit low gas permeability,
`i.e. low oxygen and
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`moisture permeability together with aroma protection, they
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`comprise a barrier layer E). This barrier layer is preferably
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`composes of an ethylene-vinyl alcohol copolymer compris-
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`ing a proportion of ethylene of 32 to 45 mol %, preferably
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`of 35 to 42 mol %. The barrier layer E) may be bonded with
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`the assistance of a coupling agent layer D) or F) on its
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`respective surface with the bonding layer C) and with the
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`heat-sealing layer G). The material used for this purpose is
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`preferably a propylene copolymer or a polyethylene which
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`comprises grafted maleic anhydride units.
`[0026] The surface layer G), which forms the 2nd outer
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`layer of the multilayer film according to the invention, is
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`preferably heat-sealable and/or peelable. This layer is thus
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`preferably produced using a low density polyethylene
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`(LDPE) with a melt flow index (MFI) in the range from 0.5
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`to 8.0 g/ 10 min, preferably in the range from 1 to 5 g/ 10 min
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`(2.16 kg, 190° C. measured according to ASTM D1238) or
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`an ionomer, such as for example a copolymer of an ot-olefin
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`and an ethylenically unsaturated carboxylic acid, wherein
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`the carboxyl groups are present in an amount of 20 to 100
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`mol % as a metal salt, preferably as a sodium salt, or an
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`ethylene-vinyl acetate copolymer with a vinyl acetate con-
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`
`tent of 3 to 10 wt. %, preferably of 4 to 6 wt. %, for the
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`production of the heat-sealable layer.
`
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`
`[0027] According to a particularly preferred embodiment,
`
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`
`the heat-sealing layer is also peelable. To this end, a blend
`
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`
`
`
`of LDPE and a polybutylene (PB) is preferably used as the
`
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`
`
`
`
`layer material. The blend preferably contains 15 to 30 wt. %,
`
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`preferably 20 to 28 wt. %, of polybutylene. The polybuty-
`
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`PAGE 3 OF 5
`
`
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`lene preferably has a melt flow index (MFI) in the range
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`from 0.3 to 2.0 g/10 min (190° C. and 2.16 kg according to
`
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`
`
`ASTM 1238).
`
`
`[0028] The thickness of the surface layer is preferably in
`
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`the range from 10 to 50 um, preferably from 15 to 30 pm.
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`[0029]
`If LDPE is used as the polymer for the production
`
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`
`of the heat-sealing layer G) and the multilayer film accord-
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`ing to the invention also comprises a barrier layer, a coupling
`
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`agent layer is then preferably necessary for bonding the
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`barrier layer and the heat-sealing layer, unless an ethylene-
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`vinyl alcohol copolymer is used as the barrier layer material.
`
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`A polyolefin, preferably a polyethylene with grafted maleic
`
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`
`
`anhydride units, may be used as the material for the coupling
`
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`agent layer. It is, however, also possible to use a blend of
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`LDPE and LLDPE in the ratio 3:1 to 4:1. The thickness of
`
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`the particular coupling agent layer is in the range from 2 to
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`8 pm, preferably in the range from 3 to 6 pm.
`
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`
`[0030] The surface layer G) may contain conventional and
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`known antibiotics, slip agents and antiblocking agents, such
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`
`as for example erucamide, polyalkylsiloxanes, such as for
`
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`
`
`example polydimethylsiloxane and/or silicon dioxide.
`
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`
`[0031] All or only individual layers of the multilayer film
`
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`
`
`according to the invention may contain stabilisers and
`
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`
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`further additives of a known kind.
`
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`
`[0032] Layer B) may moreover contain 0.5 to 2 wt. % of
`
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`a white pigment, such as for example kaolin, calcium
`
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`carbonate,
`talcum,
`titanium dioxide or mixtures thereof.
`
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`
`Such inorganic pigments are preferably added to the poly-
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`
`mer, from which layer B) is produced,
`in the form of a
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`masterbatch which contains 30 to 70 wt. % of pigments.
`
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`
`[0033] The multilayer films according to the invention
`
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`
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`
`
`may preferably be produced by conventional blown film
`
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`
`
`coextrusion processes or by flat film coextrusion processes,
`
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`
`
`inasmuch as this relates to the sequence of layers C) to G),
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`
`and is preferably bonded with the polyolefin foam layer A)
`
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`
`by an extrusion lamination step.
`
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`[0034]
`To this end, the foam layer A) and the multilayer
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`film, consisting of layers C) to G), are brought together in
`
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`
`such a manner that
`layer B) is extruded therebetween.
`
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`
`Immediately after extrusion, a sufficiently large pressure is
`
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`
`
`applied onto the resultant laminate to ensure that layers A)
`
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`
`to G) are adequately bonded to one another.
`
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`[0035]
`It is, however, also possible to produce the multi-
`
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`layer films according to the invention solely by coextrusion,
`
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`
`wherein the foam layer A) is coextruded simultaneously
`
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`
`with the other layers, optionally omitting layer C), and layer
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`A) is simultaneously foamed.
`
`
`
`[0036] The multilayer films according to the invention
`
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`
`exhibit excellent
`thermoformability on “FFS” machines
`
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`
`(forrn-fill-seal machines) and may be converted on these
`
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`
`
`machines into packaging containers, preferably into thermo-
`
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`
`
`formed packaging trays,
`then filled and sealed.
`It was
`
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`
`
`surprising that the multilayer films according to the inven-
`
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`
`tion may excellently be processed on FFS machines at an
`
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`
`elevated production speed and, in comparison with a pack-
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`
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`aging material without the modification according to the
`
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`
`
`
`invention, permit up to 10% shorter cycle times and thus an
`
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`
`
`up to 10% higher output of packaging trays without any
`
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`
`
`impairment of the uniformity of wall thickness.
`
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`
`[0037]
`In comparison with comparable known, unmodi-
`
`
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`
`
`
`fied packaging materials, the multilayer films according to
`
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`
`
`the invention also exhibit an unexpected improvement in
`
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`
`
`mechanical properties, in particular in rigidity measured by
`
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`the modulus of elasticity in machine direction and in tensile
`
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`PAGE 3 OF 5
`
`

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`US 2008/0020162 A1
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`
`
`Jan. 24, 2008
`
`
`
`[0050] Layer G) as a heat-sealing layer based on low
`
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`
`
`
`
`density polyethylene.
`[0051] The multilayer film is produced by coextrusion.
`
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`
`
`The thickness of the individual layers is stated in Table 1.
`
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`
`
`Layer
`
`Thickness
`in pm
`
`
`
`
`
`
`A)
`
`1130
`
`
`
`B)
`
`264
`
`
`
`TABLE 1
`
`D)
`5
`
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`
`C)
`
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`
`E)
`5
`
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`
`F)
`5
`
`
`
`G)
`20
`
`
`
`
`
`Total
`1444
`
`
`
`
`
`[0052] The mechanical properties of this film are stated in
`
`
`
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`
`
`Table 2.
`
`
`
`
`Comparative Example 1
`[0053] Corresponding to the multilayer film according to
`
`
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`
`
`
`Example 1, a multilayer film was produced with an identical
`
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`
`sequence of layers and, with the exception of layer A), with
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`
`
`identical layer compositions and identical film thicknesses,
`
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`
`
`wherein layer A) comprised the same polymer composition
`
`
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`
`
`
`as in Example 1, but no nucleating agent.
`
`
`
`
`
`[0054] The mechanical properties of the multilayer film
`
`
`
`
`
`
`
`
`according to the Comparative Example are stated in Table 2.
`
`
`
`
`
`
`
`TABLE 2
`
`
`Unit
`
`MPa
`
`MPa
`
`MPa
`
`
`
`
`
`
`
`
`
`
`
`MPa
`
`
`Cycles/minute
`
`
`
`
`
`Modulus of elasticity
`
`(machine direction)
`
`
`Modulus of elasticity
`
`
`(transverse direction)
`
`
`Tensile stress (machine
`
`
`
`direction)
`
`Tensile stress (transverse
`
`
`direction)
`
`Cycle times
`
`
`
`
`Comparative
`Example 1
`
`
`
`
`519
`
`
`
`280
`
`
`9.3
`
`
`7.4
`
`
`
`8
`
`
`
`Example 1
`
`
`703
`
`
`
`280
`
`
`12.0
`
`
`
`9.5
`
`
`
`9
`
`
`
`[0055]
`It is clear from Table 2 that the multilayer film
`
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`
`
`
`according to the invention exhibits far better mechanical
`
`
`
`
`
`
`
`values than a multilayer film with an unmodified foam layer
`
`
`
`
`
`
`
`
`A).
`
`1. Amultilayer film comprising the following sequence of
`
`
`
`
`
`
`
`
`layers:
`A) a base layer of polyolefin foam containing 0.5 to 25 wt.
`
`
`
`
`
`
`
`
`%, relative to the total weight of the base layer, of at
`
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`
`
`
`least one nucleating agent,
`
`
`
`
`B) a layer formed of at least one polyolefin of the foam
`
`
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`
`
`
`layer A)
`C) optionally a bonding layer comprised of a polyolefin,
`
`
`
`
`
`D) optionally a coupling agent layer,
`
`
`
`
`
`E) optionally a gas- and/or aroma-barrier layer,
`
`
`
`
`
`F) a coupling agent layer,
`
`
`
`
`G) an optionally heat-sealable and/or peelable surface
`
`
`
`
`
`
`
`layer wherein the total thickness of layers A) and B) is
`
`
`
`
`
`
`
`in the range from 0.5 to 2 mm and the thickness of layer
`
`
`
`
`
`
`B) is in the range from 1/5 to 1/2 of the thickness of layer
`
`
`
`
`
`
`
`
`
`
`A).
`
`2. Amultilayer film according to claim 1, wherein the total
`
`
`
`
`
`
`
`
`thickness of layers A) and B) is in the range from 0.6 to 1.4
`
`
`
`
`
`
`
`
`
`mm.
`
`
`
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`
`
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`
`
`
`
`3. A multilayer film according to claim 1, wherein the
`
`
`
`
`
`
`thickness of layer B) is in the range from 1/5 to 1/3 of the
`
`
`
`
`
`
`
`
`
`
`thickness of layer A).
`
`
`
`
`stress. This distinct improvement is manifested without its
`
`
`
`
`
`
`being necessary to increase the thickness of the multilayer
`
`
`
`
`
`
`
`films which are known from the prior art.
`
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`
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`
`
`[0038] The packages produced from the multilayer films
`
`
`
`
`
`
`
`
`according to the invention moreover exhibit distinctly more
`
`
`
`
`
`
`
`uniform surface structure, virtually without foam tears, so
`
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`
`
`
`
`
`
`likewise improving the handling thereof.
`
`
`
`
`
`[0039] The present invention accordingly also provides
`
`
`
`
`
`
`
`the use of the multilayer film according to the invention as
`
`
`
`
`
`
`
`
`a packaging material, preferably on form-fill-seal machines
`
`
`
`
`
`
`(FFS machines), for packaging foodstulfs, in particular for
`
`
`
`
`
`
`
`
`packaging of highly perishable foodstulfs, such as meat,
`
`
`
`
`
`
`
`ham or sliced foodstulfs. Since packaging is often carried
`
`
`
`
`
`
`
`out discontinuously on these machines, in order to package
`
`
`
`
`
`
`different products, the packaging material must also exhibit
`
`
`
`
`
`
`
`
`a relatively wide thermoforming “window” over which it
`
`
`
`
`
`
`
`may be therrnoformed. This is the case for the packaging
`
`
`
`
`
`
`
`
`material according to the invention, as it exhibits excellent
`
`
`
`
`
`
`thermoformability, in particular vacuum formability.
`
`
`
`
`[0040] The thermoformed, preferably vacuum formed
`
`
`
`
`
`
`packaging articles, such as for example packaging trays,
`
`
`
`
`
`
`
`preferably vacuum formed packaging trays, which have
`
`
`
`
`
`
`
`been produced from the multilayer films according to the
`
`
`
`
`
`
`
`
`invention, may, once filled, be sealed with known lidding
`
`
`
`
`
`
`
`
`
`films. Suitable lidding films are multilayer films, preferably
`
`
`
`
`
`
`
`
`made from polyethylene terephthalate/SiOx/coupling agent
`
`
`
`
`
`
`
`
`
`
`
`layer/low density polyethylene or from polyethylene tereph-
`
`
`
`
`thalate/coupling agent
`layer/polyethylene/coupling agent
`
`
`
`
`layer/ethylene-vinyl
`alcohol
`copolymer/coupling agent
`
`layer/polyethylene.
`the first-stated
`[0041] Among the stated lidding films,
`
`
`
`
`
`
`
`multilayer films are in particular suitable. To this end, the
`
`
`
`
`
`
`
`
`
`biaxially oriented polyethylene terephthalate is coated with
`
`
`
`
`
`
`SiOX by plasma vacuum processing. The already fabricated
`
`
`
`
`
`
`
`polyethylene film is then laminated thereto with the assis-
`
`
`
`
`
`
`
`
`tance of a coupling agent. Such a lidding film is in particular
`
`
`
`
`
`
`
`
`distinguished by excellent transparency and elevated break-
`
`
`
`
`
`
`ing strength. Packages comprising such a lidding film more-
`
`
`
`
`
`
`
`
`over exhibit excellent gas barrier properties.
`
`
`
`
`
`
`[0042]
`In the following Examples, modulus of elasticity
`
`
`
`
`
`
`
`and tensile stress are determined according to ISO 527-2 in
`
`
`
`
`
`
`
`
`machine direction and in the transverse direction.
`
`
`
`
`
`
`
`EXAMPLES
`
`
`
`
`Example 1
`
`[0043] A multilayer film according to the invention with
`
`
`
`
`
`
`following layer structure:
`
`
`
`[0044] Layer A) a foam layer with a density of 0.47 g/cm3
`
`
`
`
`
`
`
`
`and a cell count of 492 cells/mm3 made from a blend of
`
`
`
`
`
`
`
`
`50 wt. % polypropylene with long-chain branching (high
`
`
`
`
`
`
`
`melt strength polypropylene) and 46 wt. % of a het-
`
`
`
`
`
`
`
`erophase propylene-ethylene block copolymer and 4 wt.
`
`
`
`
`
`
`% of finely divided talcum.
`
`
`
`
`[0045] Layer B) made from 100 wt. % of a heterophase
`
`
`
`
`
`
`
`propylene-ethylene block copolymer corresponding to the
`
`
`
`
`
`block copolymer of foam layer A)
`
`
`
`
`[0046] Layer C) made from a polypropylene,
`
`
`
`
`
`[0047] Layer D) made from a coupling agent based on
`
`
`
`
`
`
`
`polypropylene grafted with maleic ar1hydride units,
`
`
`
`
`
`
`[0048] Layer E) as a gas barrier layer based on an ethyl-
`
`
`
`
`
`
`
`
`
`
`ene-vinyl alcohol copolymer,
`[0049] Layer F) as a coupling agent layer with the same
`
`
`
`
`
`
`
`
`structure as layer D),
`
`
`
`
`PAGE 4 OF 5
`
`PAGE 4 OF 5
`
`

`
`
`
`US 2008/0020162 A1
`
`
`
`Jan. 24, 2008
`
`
`
`
`
`
`
`13. A packaging material comprising the multilayer film
`
`
`
`
`
`
`of claim 1.
`
`
`14. A packaging container made from a film of claim 1.
`
`
`
`
`
`
`
`15. A method for packaging foodstulfs, which comprises
`
`
`
`
`
`
`
`packaging said foodstuffs in a packaging container of claim
`
`
`
`
`
`
`14.
`16. The method of claim 24, wherein said solid foodstuffs
`
`
`
`
`
`
`
`
`are meat, sausage or cheese.
`
`
`
`
`17. A method for preparing a packaging material which
`
`
`
`
`
`
`
`comprises preparing said packaging material of a multilayer
`
`
`
`
`
`
`film of claim 1 on a form-fill-seal machine.
`
`
`
`
`
`18. The multilayer film of claim 4, wherein said propy-
`
`
`
`
`
`
`
`
`lene-ethylene copolymer is a heterophase propylene-ethyl-
`
`
`
`
`ene block copolymer.
`
`
`
`19. The multilayer film of claim 5, wherein said amount
`
`
`
`
`
`
`
`of nucleating agent is 2.5 to 15 wt. %.
`
`
`
`
`
`
`
`20. The multilayer film of claim 8, wherein said layer C)
`
`
`
`
`
`
`
`
`is polypropylene.
`
`
`21. The multilayer film of claim 10, wherein said heat-
`
`
`
`
`
`
`
`
`
`sealable polymer is a low density polyethylene or an iono-
`
`
`
`
`
`
`mer.
`
`
`
`
`22. The multilayer film of claim 11, wherein said peelable
`
`
`
`
`
`
`
`
`
`polymers are a blend of low density polyethylene and a
`
`
`
`
`
`
`
`
`
`polybutylene.
`23. The multilayer film of claim 12, wherein said total
`
`
`
`
`
`
`
`
`thickness of layers C) to G) is 30 to 50 um.
`
`
`
`
`
`
`
`24. The method of claim 15, wherein said foodstuffs are
`
`
`
`
`
`
`
`
`solid foodstulfs.
`
`
`
`
`
`
`
`4. A multilayer film according to claim 1, wherein layer A)
`
`
`
`
`
`
`
`is comprised of foamed polypropylene or a foamed blend of
`
`
`
`
`
`
`polypropylene with long-chain branching and a propylene-
`
`
`
`
`
`
`
`
`ethylene copolymer.
`5. A multilayer film according to claim 1, wherein layer A)
`
`
`
`
`
`
`
`contains 2.1 to 20 wt. % of the nucleating agent.
`
`
`
`
`
`
`
`
`6. A multilayer film according to claim 1, wherein said
`
`
`
`
`
`
`
`nucleating agent comprises at least one member of the group
`
`
`
`
`
`
`
`consisting of talcum, titanium dioxide, silicon oxide, cal-
`
`
`
`
`
`
`
`
`cium carbonate, magnesium silicate, aluminum silicate, cal-
`
`
`
`
`
`
`
`cium phosphate and montmorillonite.
`
`
`
`
`7. A multilayer film according to claim 1, wherein layer B)
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`is formed of polypropylene or a propylene-ethylene copoly-
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`mer.
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`8. A multilayer film according to claim 1, wherein layer C)
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`is present and said polvolefin is formed of the monomer
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`which is the greatest monomer component of the polyolefin
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`of the foam layer A).
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`9. A multilayer film according to claim 1, wherein layer E)
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`is present and is formed of an ethylene-vinyl alcohol copoly-
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`mer.
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`10. A multilayer film according to claim 1, wherein layer
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`G) is present and is formed of a heat-sealable polymer, and
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`optionally contains conventional additives.
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`11. A multilayer film according to claim 1, wherein layer
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`G) is formed of peelable polymers and optionally contains
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`conventional additives.
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`12. A multilayer film according to claim 1, wherein the
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`total thickness of layers C) to G) amounts to 20 to 70 um.
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`PAGE 5 OF 5
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`PAGE 5 OF 5