EP2381791A1

EP2381791A1 - Multilayer, tube-shaped food film

Info

Publication number: EP2381791A1
Application number: EP09743874A
Authority: EP
Inventors: Jürgen SCHIFFMANN
Original assignee: Kuhne Anlagenbau GmbH
Current assignee: Kuhne Anlagenbau GmbH
Priority date: 2008-12-23
Filing date: 2009-10-27
Publication date: 2011-11-02
Also published as: AU2009331976A1; NZ593066A; DE102008062937A1; CN102264233A; RU2011121051A; CA2743797A1; ZA201103829B; JP2012513190A; KR20110103975A; MX2011005911A; WO2010072281A1; CA2743797C; RU2489885C2; US20110250462A1; UA102001C2; AU2009331976B2; BRPI0922133A2

Abstract

The present invention relates to a multilayer, tube-shaped food film, particularly a sausage casing, wherein the food film is produced on a multilayer coextrusion blow film system by means of coextruded plastics fed to a blow head, and is stretched biaxially in a triple-bubble process. The food film comprises at least six layers. The at least six layers of the food film are thereby disposed as follows, from outside to inside: an outermost layer having a polyamide as a layer component, an innermost layer having a polyamide as a layer component, and a sequence of at least intermediate layers disposed therebetween, disposed as follows from outside to inside: a layer comprises a bonding agent as a layer component, a further layer comprises a polyolefin as a layer component, a further layer comprises a polyolefin as a layer component, and a further layer comprises a bonding agent as a layer component. The present invention further relates to a multilayer, flat food film produced from a multilayer, tube-shaped food film cut open for this purpose.

Description

description

Multilayer, tubular food film

The present invention relates to a multilayer, tubular food film, in particular sausage casing, wherein the food film is produced on a multi-layer coextrusion blown film plant by means of a blow head supplied coextruded plastics and in the triple-bubble process and biaxially stretched, according to the preamble of claims 1 and 6-13. The invention further relates to a multi-layer, sheet-like food casing according to claim 19.

In practice, 1-, 3-, 5- or 7-layered, tubular films are already used as a sausage casing or artificial casing for packaging pasty foods. The food or food to be packaged, such as sausage meat, is filled into the artificial casing, brewed therein, cooled and stored.

From use as food packaging, there are requirements for such a food film, such as, for example, pronounced dimensional stability over the entire processing process or adequate protection of the contents against undesired external influences, such as oxygen access, UV radiation, drying out or the like.

In addition, today high demands are placed on the visual appearance of food packaging. kung and in particular provided by sausage casings. Thus, food packaging increasingly promotional character. In this way, they should transport advertising messages and exert direct influence on the consumer's purchase decision. This, in turn, requires that food packaging, in addition to a first-class print image also have optimal colorability.

For example, document EP 0 467 039 B1 describes a multilayer packaging film for use as a sausage casing. This packaging casing consists of three or five layers, wherein the outer and the inner layer consists of polyamides (PA) and the middle layer consists of a polymer mixture with polyolefin (PO). It is proposed to print the outer PA layer and incorporate dyes or color pigments in the middle PO layer.

A disadvantage of this construction is that the middle layer can satisfactorily fulfill none of the requirements imposed on it, such as a suitable water vapor barrier, good adhesion properties to the outer PA layers and a homogeneous colorability. Thus, the water vapor barrier property of the PO is significantly reduced by the addition of adhesion promoters (short: HV) and / or color pigments compared to a pure PO layer. In addition, the effect of only partially present HV is considerably weaker compared to a pure HV layer. In addition, the addition of color pigments to the middle layer leads to a further deterioration of the adhesion. Thus, a desired colorability of the middle layer with return view of the other requirements to be met only to a limited extent.

After the inner layer is to be designed as a very thin layer, in this layer construction, a sufficient oxygen barrier is possible only conditionally or with the restriction of other properties.

Apart from this is in this known sausage casing a desired, homogeneous and opaque coloring only with considerable restriction of other properties, such as the composite or Bräthaftung possible.

The document DE 43 39 337 C2 discloses an advantageous further development of the 3-layer sausage casing. Their 5-layer structure has a separate HV layer between the outer / inner PA layer and the middle PO layer. The resulting 5-layer sausage casing therefore offers improved composite adhesion compared to the 3-layer. In addition, attention is drawn to the good printability and adhesion of the printing inks on the outer PA layer.

However, other properties, such as a high oxygen barrier and / or a colorability of several layers, can not be realized sufficiently with this structure.

The document EP 1 290 948 A1 likewise describes a 3- or 5-layer sausage casing based on PA in the outer and inner layer. Their 5-layered embodiment differs from the 5-layered sausage casing of the specification DE 43 39 337 C2 discussed above only by the polymers used, in particular with regard to the PO and - A -

HV layers. Thus, for the middle layer ethylene-Ci.g-alkyl acrylate copolymers and ethylene-maleic anhydride copolymers are provided. In a 5-layer embodiment, a middle layer based on ethylene-C 1-6 -alkyl acrylate copolymers of two layers based on ethylene-maleic anhydride copolymers and / or Surrounded by alkyl acrylate-maleic anhydride copolymers.

A disadvantage of this layer structure is that the ethylene-methyl acrylate copolymer-based layers used have a lower water vapor barrier than the POs otherwise used, such as polyethylene (PE for short) or polypropylene (PP for short). It is merely an alternative solution to other 5-layer sausage casings with the same limitations on colourability and oxygen barrier properties.

In the documents DE 102 27 580 A1 and DE 102 54 172 A1 of the same applicant, 7-layer structures for food casings are described for the first time. The food casings disclosed in the document DE 102 27 580 A1 have the structure of layers from outside to inside, wherein subsequently the delimitation of the individual layers from each other is indicated by the symbol "| | "is shown:

a) PA I I EVOH I I HV I I PO I I HV I I PA; b) PA I I EVOH I I PA I I HV I I PO I I HV I I PA;

C) PA II HV II PA II EVOH | | PA | | HV | | PA; d) PO II HV II PA II EVOH | | PA | | HV | | PO; e) polyethylene terephthalate (PET for short) || HV || PA || EVOH II PA II HV II PO; or f) PO II ethylene-vinyl alcohol copolymer (short: EVA) | | HV II EVOH II HV II EVA | | PO.

In document DE 102 54 172 A1, the layer structures (a) to (f) described above are analogous to

Polyvinyl alcohol (short: PVA) instead of the EVOH described.

The simplified name "EVA" commonly used by the Applicant and some practitioners in the practice of an ethylene-vinyl alcohol or ethylene-vinyl alcohol copolymer is identical to the standard term "EVOH" used in the following description. The simplified name "PVA", which is also frequently used in practice, is identical to the standardized designation "PVOH" used in the following description.

These layer sequences with an additional EVOH or PVOH layer, in comparison to the 5-layer

Food casing significantly improves the oxygen barrier. Furthermore, the desired mechanical

Properties are at least largely achieved.

However, the proposed food shells can still be improved, in particular with regard to optimum colorability.

In order to increase the opacity of the colored PO layer and the brilliance of the colors, usually the innermost, the food, such as sausage meat, facing PA layer is colored white. Since the purpose of this PA layer is essentially to ensure sufficient frying adhesion to the packaged food, its layer thickness can be chosen to be relatively low. This is a high percentage added to masterbatch to achieve sufficient coloration. In addition to the reduction in the oxygen barrier, this also has the disadvantage of reducing the frying adhesion of the PA layer. In addition, even with high pigment additions a satisfactory coloring due to the small layer thickness is not or only partially possible.

Accordingly, it is an object of the present invention, while avoiding the disadvantages discussed above, to develop a generic, multilayer, tubular food film in such a way that a sufficiently opaque colorability can be achieved.

It is an aspect of the invention to develop a generic, multilayer, tubular food film such that a reduction in the frying adhesion of the innermost layer in contact with the foodstuff is prevented.

It is a further aspect of the invention to develop a generic, multilayer, tubular food film in such a way that water vapor diffusion through the film is prevented.

It is another aspect of the invention to further develop a generic multilayer tubular food film such that greater flexibility in the selection of materials for individual layers is achieved.

It is a further aspect of the invention to develop a generic, multilayer, tubular food foil such that a long Durability of the packaged food, especially in foods with a high moisture content, is achieved.

It is a further aspect of the invention to develop a generic, multilayer, tubular food film in such a way that a high mechanical strength, in particular an optimal shrinkage and / or a high overstretching factor, is achieved.

The object is achieved by the food film having the features of at least one of claims 1 and 6 to 13 and the food casing according to claim 19.

According to the invention, a multilayer, tubular food film, in particular a sausage casing, is proposed for the first time, wherein the food film is produced and biaxially stretched on a multilayer coextrusion blown film line by means of a coextruded plastic supplied by a blow head and in a triple bubble process. The food film has at least six layers, wherein the at least six layers of the food film are arranged from outside to inside as follows: an outermost layer having a PA as a constituent layer, an innermost layer having a PA as a constituent layer, and an intervening sequence of at least four intermediate layers arranged from outside to inside as follows: one layer has an HV as a constituent layer, another layer has a PO, preferably PP, as a constituent layer, - a further layer has a PO, preferably PP, as a constituent layer, and a further layer has an HV as a constituent layer.

Here, the two separate, juxtaposed PO layers advantageously allow the desired colorability in terms of opacity and color brilliance. Thus, on the one hand, the total amount of pigments introduced can be increased. On the other hand, the coloring of two different PO layers of previously uncoupled or combinable types of pigment can be used in a food casing. From this, new color effects can be created which previously could not be achieved by coloring only one PO layer.

Another advantage of the separate coloring of two PO layers is that the available color masterbatches, i. Color / additive / combination concentrates or polymer-bound additives, such as color pigments, are less expensive and more readily available than the color masterbatches suitable for coloring other polymer layers. In addition, the number of PO color master batch suppliers is significantly larger.

At the same time, an excellent water vapor barrier is available due to the two separate PO layers, which is especially true for sausages or other which are fresh in need, is advantageous. A food packaged with the food casing or film according to the invention therefore remains fresh for a particularly long time.

Due to the low permeability to water vapor, furthermore, the mass losses during storage of the food, in particular of sausage, remain low. This is of considerable economic importance, since most foods, especially sausages, are traded at a mass selling price. In the process, mass losses during storage due to water vapor diffusion through the packaging lead to a reduction of the achievable revenue.

The outermost PA layer of the proposed foodstuff film according to the invention is not intended for coloring. Thus, the adhesion of printing inks is not affected by pigments present on the surface, whereby the outermost PA layer is particularly well inscribable or printable.

Furthermore, according to the present invention, the conventional coloring of the innermost PA layer is not required, thus avoiding the above-discussed disadvantages of a reduced oxygen barrier and a deteriorated frying adhesion. Thus, the food film is particularly suitable as a sausage casing, since the innermost PA layer has a particularly good Bräthaftung to sausage mass in the first proposed layer structures. Especially sausage shows, when packed with the food film according to the invention, even after long storage a wrinkle-free, tight-fitting casing. Here arise between the sausage mass and the innermost layer of Sausage casing due to the particularly good Bräthaftung no gaps, thereby avoiding the discontinuation of jelly from the sausage meat is avoided.

Advantageous developments of the food film according to the invention are the subject of the dependent claims 2 to 5 and 14 to 19.

Thus, the at least four intermediate layers can follow one another directly adjacent to one another.

This results in a compact and cost-effective layer structure with a total of six layers, which realizes the advantages mentioned above. This is further characterized by a simple manufacturability.

The food film may have at least one further layer which is arranged in the at least four intermediate layers between the two PO layers having intermediate constituents, this at least one further layer being an HV or an EVOH or ethylene-vinyl alcohol copolymer or a PA Layer component has.

The use of a further layer in the form of an HV, which is arranged between the two PO layers of the four intermediate layers, allows an even better bond adhesion between these layers. This in turn allows the use of two substantially different PO and thus greater flexibility in the selection of materials for the two PO layers with good bond adhesion. In addition, the at least one further layer arranged between the two POs as layer constituents can either be a sequence of three layers, one of which has an HV as a constituent layer, a further layer having an EVOH as constituent layer, and a further layer HV has as a Schientbestand- part, or is a sequence of five layers, one of which has a HV HV as a constituent layer, another layer has a PA as a constituent layer, another layer has an EVOH as a constituent layer, another layer has a PA as a constituent layer has, and - a further layer has an HV as a layer constituent.

As further studies have shown, a separate high-barrier layer, such as, for example, EVOH or ethylene-vinyl alcohol copolymer, results in an oxygen permeation of less than 10 cm ³ / (m ² -day-bar) to be desired for food packaging.

In addition, the placement of the EVOH layer between two HV layers, which in turn are sandwiched between the two PO layers, provides further enhanced protection of the EVOH layer from moisture and other external influences. This will a sufficient barrier effect against moisture even when using the HV in a thin layer used, which is particularly advantageous in view of the high price of the HV.

In particular, when using the food film according to the invention as a sausage casing, the mechanical strength is of considerable importance. The strength, but also the barrier properties discussed above, depend essentially on the adhesion of the individual layers to one another.

Since the film composite is subject to extremely great mechanical stress during the biaxial stretching process, with the currently available HV, it is only possible to some extent to achieve optimum adhesion of the HV with the EVOH layer. However, since it is possible to achieve a very good adhesion with the PA layers by means of HV and PA in turn assumes excellent adhesion with the EVOH layer, by embedding the EVOH layer between two additional PA layers a further improved, optimal Bonding adhesion can be achieved.

In addition, the food film between the outermost layer of PA and the sequence of at least four intermediate layers each based on HV, PO, PO, HV at least two further layers are each based on PA or EVOH or HV, these from the outside preferably either a layer having an EVOH as a constituent layer inside, and a layer having a PA as a constituent layer, or preferably a layer having an HV as a constituent layer, a layer having an EVOH as a constituent layer, and having a layer having a PA as a constituent layer.

After the oxygen barrier of EVOH or ethylene-vinyl alcohol copolymer is reduced by moisture absorption, in the layer structure described above, EVOH is advantageously arranged in the outer region of the layer composite. Namely, the PO layers located further inside provide sufficient protection of the EVOH layer from moisture from the packaged food.

Since PA and EVOH have a very good bond with each other, the EVOH layer can be applied directly to a PA layer without another HV.

In some applications, it may also be necessary to protect the moisture-sensitive EVOH layer from the outside from moisture penetration. Since most HV are PO-based, they also provide protection against moisture penetration. Therefore, by disposing an HV layer between the outermost layer and the EVOH layer, even greater protection against moisture from the outside can be provided. Thus, the effectiveness of the EVOH oxygen barrier can be maintained.

In a preferred embodiment, the increase in brightness of the colored foodstuff film according to the invention can be in the range of 5 to 20%, preferred wise from 6 to 15%, in particular from 7 to 10% compared to a 5-layer standard film amount. Furthermore, the increase in brilliance of a preferred embodiment may be in the range of 8 to 30%, preferably 9 to 25%, especially 10 to 15%, over a 5-layer standard film. This advantage of the food film according to the invention can be seen from the following example comparison:

A) Standard sausage casing (5-layer with layer sequence PA

I I HV I I PO II HV II PA)

Light / observer Brightness Brilliance Conditions L * C *

1) D65 10 Deg 47 43 56 56

2) FlI 10 deg 51 08 59 30

3) A 10 deg 54 70 66 18

B) Sausage casing according to the invention with separately colored PO layers (here for example 7-layer with layer sequence PA I I HV I I PO I I HV I I PO I I HV I I PA)

C) difference between standard sausage casing according to A) and exemplary sausage casing according to the invention according to B)

Illum / Observer conditions:

1) D65 10 Deg = daylight 300 Nm - 700 Nm;

2) FIl 10 Deg = fluorescent tubes, very high energy emissions at wavelengths 400

Nm, 550 Nm and 640 Nm; and

3) A 10 Deg = household light bulb, almost none

UV radiation, hardly blue parts but for a high proportion of red.

Measurement method used for this: CIE L * a * b Color difference standard.

In this way, according to the invention, it is possible to realize a food foil and in particular a sausage casing with an optimal dyeability and at the same time a first-class printed image. This in turn opens up much more design options for the visual appearance of the food film than previously available.

In this case, the shrinkage of the food film may be in the range of 5 to 30%, preferably 12 to 15%. The overstretching factor of the food film may be in the range of 2 to 20%, preferably 10 to 12%.

With the multilayer constructions according to the invention, foodstuffs films, in particular sausage casings, are advantageously produced, the mechanical properties suitable for the respective intended use, such as optimum shrinkage and optimum overstretching factor.

For some applications, the longest possible shelf life of the packaged food is needed. This requires the highest possible oxygen barrier, which can not be achieved by means of the PA layers or any mixtures in these layers.

Thus, the oxygen permeability is conventional PA-bodies without EVOH about 26 to 29 cm ³ / (m ² -day-bar) at 23 ⁰ C and 0% relative humidity and about 32 to 34 cm ³ / (m ² -Day bar) at 23 ⁰ C and 85% relative humidity (measured according to ISO 15 105-1). This value does not depend on whether the food film is 3-, 5- or 7-layered.

In contrast, in an advantageous embodiment, the oxygen permeability of the inventive food film may be less than 10 cm ³ / (m ² -day bar), preferably less than or equal to 3 cm ³ / (m ² -day bar) at 23 ^° C. and 0 ° % relative humidity and / or less than or equal to 9 cm ³ / (m ² day bar) at 23 ⁰ C and 85% relative humidity, be (measured according to ISO 15 105-1).

Thus, by using an EVOH layer, significantly less oxygen permeation through the food sheet can be achieved, while maintaining the advantages discussed above.

In a further advantageous embodiment, the water vapor permeability of the food film can be less than 3 g / (m ² -day bar), in particular in the range from about 1.5 to 2.5 g / (m ² day bar), at 23 ⁰ C and 50% relative humidity (measured according to ISO 15 106-1).

Thanks to the low water vapor permeability of the food film according to the invention, a moisture-sensitive EVOH layer can be effectively protected from moisture. This results in a high oxygen barrier of the EVOH layer and thus of the entire food film. In addition, the packaged food is prevented from drying out and mass loss avoided, as discussed above.

The food film according to the invention can be produced particularly well with corresponding systems of the same applicant and further processed.

Particularly advantageous embodiments of the food film according to the invention are described in claims 6 to 13 as follows:

According to the invention, a multilayer, tubular food film, in particular sausage casing, is proposed, wherein the food film is produced on a multilayer coextrusion blown film line by means of a blow head fed, coextruded plastics and biaxially stretched in the triple-bubble process. The food sheet has at least six layers, the layers of the food sheet being arranged in a sequence from outside to inside as follows: a first layer from the outside, ie, the outermost layer, with a PA as a layer component; a second layer from the outside with an HV as a layer constituent; a third layer from the outside with a PO, preferably PP, as Schichtbe- constituent part; a fourth layer from the outside with a PO, preferably PP, as a layer component; a fifth layer from the outside with an HV as a layer component; and a sixth layer from the outside, ie, the innermost layer, with a PA as a constituent layer.

Furthermore, according to the invention, a multilayer, tubular food film, in particular sausage casing, is proposed, wherein the food film is produced and biaxially stretched on a multi-layer coextrusion blown film line by means of a blow head supplied, coextruded plastics and in the triple-bubble process. The food sheet has at least seven layers, the layers of the food sheet being arranged in a sequence from the outside to the inside as follows: a first layer from the outside, i.e., the outermost layer, with a PA as a layer component; a second layer from the outside with an HV as a layer constituent; a third layer from the outside with a PO, preferably PP, as a layer constituent; a fourth layer from the outside with an HV as a layer component; a fifth layer from the outside with a PO, preferably PP, as a layer constituent; a sixth layer from the outside with an HV as a layer component; and a seventh layer from the outside, i. the innermost layer, with a PA as the constituent layer.

In addition, according to the invention, a multilayer, tubular food film, in particular sausage casing, is proposed, wherein the food film is produced on a multilayer coextrusion blown film line by means of a coextruded plastic fed to a blow head and stretched biaxially in the triple bubble process. The food film has at least eight layers, the layers the food film in a sequence from the outside to the inside are arranged as follows: a first layer from the outside, ie, the outermost layer, with a PA as a layer component; a second layer from the outside with EVOH or ethylene-vinyl alcohol copolymer as a layer component; a third layer from the outside with a PA as a constituent layer; a fourth layer from the outside with an HV as a layer component; a fifth layer from the outside with a PO, preferably PP, as a layer constituent; a sixth layer from the outside with a PO, preferably PP, as a layer component; a seventh layer from the outside with an HV as a layer component; and an eighth layer from the outside, ie, the innermost layer, with a PA as a constituent layer.

According to the invention, a multilayer, tubular food film, in particular sausage casing, is also proposed, wherein the food film is produced and biaxially stretched on a multi-layer coextrusion blown film line by means of a blow head supplied, coextruded plastics and in the triple bubble process. The food sheet has at least nine layers, wherein the layers of the food sheet are arranged in a sequence from outside to inside as follows: a first layer from the outside, ie, the outermost layer, with a PA as a layer component; a second layer from the outside with EVOH or ethylene-vinyl alcohol copolymer as a layer component; a third layer from the outside with a PA as a constituent layer; a fourth layer from the outside with an HV as a layer component; a fifth layer from the outside with a PO, preferably PP, as a layer constituent; a sixth layer from the outside with an HV as a layer component; a seventh layer from the outside with a PO, preferably PP, as A layer component; an eighth layer from the outside with an HV as a layer component; and a ninth layer from the outside, ie, the innermost layer, with a PA as a constituent layer.

Furthermore, a multilayer, tubular food film, in particular a sausage casing, is proposed, wherein the food film is produced on a multi-layer coextrusion blown film line by means of coextruded plastics fed to a blow head and stretched in a biaxial triple-bubble process. The food sheet has at least nine layers, the layers of the food sheet being arranged in a sequence from the outside to the inside, as follows: a first layer from the outside, i. the outermost layer, with a PA as a constituent layer; a second layer from the outside with an HV as a layer constituent; a third layer from the outside with EVOH as a constituent layer; a fourth layer from the outside with a PA as a layer component; a fifth layer from the outside with an HV as a layer component; a sixth layer from the outside with a PO, preferably PP, as a layer component; a seventh layer from the outside with a PO, preferably PP, as a layer component; an eighth layer from the outside with an HV as a layer component; and a ninth layer from the outside, i. the innermost layer, with a PA as the constituent layer.

According to the invention, a multilayer, tubular food film, in particular sausage casing, is also proposed, wherein the food film is produced on a multilayer coextrusion blown film line by means of a coextruded plastic fed to a blow head and in the triple-bubble process and stretched biaxially. The food sheet has at least ten layers, the layers of the food sheet being arranged in a sequence from outside to inside as follows: a first layer from the outside, ie, the outermost layer, with a PA as a layer component; a second layer from the outside with an HV as a layer constituent; a third layer from the outside with EVOH as a constituent layer; a fourth layer from the outside with a PA as Schichtbe- part; a fifth layer from the outside with an HV as a layer component; a sixth layer from the outside with a PO, preferably PP, as a layer component; a seventh layer from the outside with an HV as a layer component; an eighth layer from the outside with a PO, preferably PP, as a layer component; a ninth layer from the outside with an HV as a layer component; and a tenth layer from the outside, ie the innermost layer, with a PA as Schichtbeεtandteil.

Furthermore, a multilayer tubular food film, in particular a sausage casing, is proposed, wherein the food film is produced and biaxially stretched on a multi-layer coextrusion blown film line by means of coextruded plastics supplied by a blow head and in a triple bubble process. The food sheet has at least nine layers, the layers of the food sheet being arranged in a sequence from outside to inside as follows: a first layer from the outside, ie, the outermost layer, with a PA as a layer component; a second layer from the outside with an HV as a layer constituent; a third layer from the outside with a PO, preferably PP, as a layer constituent; a fourth layer from the outside with an HV as a layer component; a fifth layer from the outside with EVOH as a layer component; a sixth layer from the outside with an HV as a layer component; a seventh layer from the outside with a PO, preferably PP, as a layer component; an eighth layer from the outside with an HV as a layer component; and a ninth layer from the outside, ie, the innermost layer, with a PA as a constituent layer.

According to the invention, a multilayer, tubular food film, in particular sausage casing, is also proposed, wherein the food is produced and biaxially stretched on a multilayer coextrusion blown film line by means of a coextruded plastic fed to a blow head and in a triple bubble process. The food sheet has at least eleven layers, wherein the layers of the food sheet are arranged in a sequence from the outside to the inside as follows: a first layer from the outside, ie, the outermost layer, with a PA as a layer component; a second layer from the outside with an HV as a layer constituent; a third layer from the outside with a PO, preferably PP, as a layer component; a fourth layer from the outside with an HV as a layer component; a fifth layer from the outside with a PA as a constituent layer; a sixth layer from the outside with EVOH as a constituent layer; a seventh layer from the outside with a PA as a constituent layer; an eighth layer from the outside with an HV as a layer component; a ninth layer from the outside with a PO, preferably PP, as a layer component; a tenth layer from the outside with a HV as a layer component; and an eleventh layer from the outside, ie, the innermost layer, with a PA as a constituent layer. It is further proposed a multilayer, sheet-shaped food casing, which is made of a sliced, multi-layer, tubular food sheet according to this invention. This food casing has all the advantages of the food casing according to the invention.

The invention allows not only the illustrated embodiments but also further design approaches.

For the purposes of this application, PO may be a substance selected from a group consisting of PP, PE, polyolefin plastomer (POP for short), ethylene-vinyl acetate copolymers (EVAC for short), ethylene-methyl methacrylate copolymers (abbreviated to: EMMA), ethylene-methacrylic acid copolymers (EMA for short), ethylene-acrylic acid copolymers (EAA for short), copolymers of cycloolefins / cycloalkenes and 1-alkenes or cycloolefin copolymers (COC for short), or a mixture thereof , Further, PO may be a mixture of the above PO with ionomers.

HV stands for adhesive layers, which ensure a good bond between the individual layers. In this case, HV can be based on a base material selected from a group consisting of PE, PP, EVAC, EMA, EMMA, EAA and an ionomer, or a mixture thereof.

According to a further preferred embodiment, layers which comprise HV as a layer component may also comprise a mixture of PO and HV or a mixture of EVAC, EMA, EMMA and / or EAA and HV or a mixture of ionomer and HV or a mixture of a plurality of HV have. Furthermore, it can be provided that layers which comprise EVOH as a layer constituent have, instead of EVOH, a modified PA of m-xylylenediamine and adipic acid (abbreviated to MXD6) or PVOH.

According to a further embodiment it can be provided that layers which comprise EVOH or PVOH or MXD6 have mixtures of these substances or mixtures of these substances with PA.

According to the invention, PA may be a substance selected from a group consisting of PA of ε-caprolactam or poly (ε-caprolactam) (in short: PA6), PA of hexamethylenediamine and adipic acid or polyhexamethyleneadipinamide (abbreviated to PA6.6), PA of ε-caprolactam and hexamethylenediamine / adipic acid (abbreviated to PA6.66), PA of hexamethylenediamine and dodecanedioic acid or polyhexamethylenedodecam- namide (abbreviated to PA6.12), PA of 11-aminoundecanoic acid or polyundecanamide (abbreviated to: PAlI), PA from 12-laurolactam or poly (ω-laurolactam) (in short: PA12), or a mixture of these PA or a mixture of these PA with amorphous PA or with other polymers. The general notation PAx. y is synonymous with PAx / y or PAxy.

In addition, it can be provided that layers which comprise PA as a layer constituent have, instead of PA, an MXD6 or ionomer.

According to a further embodiment it can be provided that layers comprising PA or MXD6 have mixtures of PA and EVOH or PA and PVOH or PA and MXD6. The layer of the foodstuff film according to the invention referred to in this description as the innermost layer is in contact with the foodstuff to be packaged, in particular a sausage mass. The layer of the food film according to the invention, referred to as outermost layer in this specification, closes off the food film towards the environment.

For the purposes of this invention, the designation of a material as a "layer constituent" means that a layer of the foodstuff film according to the invention has at least partially this material, wherein the term "layer constituent" in the sense of this invention may in particular include that the layer consists entirely of this material ,

Claims

claims

1. Multilayer, tubular food film, in particular sausage casing, wherein the food film is produced on a multi-layer coextrusion blown film plant by means of coextruded plastics supplied with a blow head and biaxially stretched in the triple bubble process, characterized in that the Food film has at least six layers, wherein the at least six layers of the food sheet are arranged from outside to inside as follows: an outermost layer with a polyamide as a layer component, an innermost layer with a polyamide as a layer component, and an interposed sequence of at least four Intermediate layers which are arranged from outside to inside as follows: one layer has a bonding agent as a layer component, a further layer comprises a polyolefin as a layer component, a further layer comprises a polyolefin as a layer component, and a further layer has one

Adhesive as a constituent layer on.

2. Multilayer, tubular food wrap according to claim 1, characterized in that the at least four intermediate layers immediately adjacent to each other follow each other.

3. Multilayer, tubular food film according to claim 1, characterized in that the food film has at least one further layer which is arranged in the at least four intermediate layers between the two polyolefin layer constituent having intermediate layers, which at least one further layer of a bonding agent or an ethylene - Having vinyl alcohol copolymer or a polyamide as a layer component.

4. Multilayer, tubular food film according to claim 3, characterized in that arranged between the two polyolefin layer component having intermediate layers, at least one further layer is either a series of three layers, one of which layer has a bonding agent as a layer constituent, another Layer comprises an ethylene-vinyl alcohol copolymer as a layer constituent, and a further layer comprises a bonding agent as a layer constituent, or a sequence of five layers, of which - one layer has a bonding agent as a layer constituent, another layer having a polyamide as a constituent layer . a further layer comprises an ethylene-vinyl alcohol copolymer as the constituent layer, a further layer comprises a polyamide as the constituent layer, and - a further layer has an adhesion promoter as a constituent layer.

5. Multilayer, tubular food film according to at least one of claims 1 to 4, character- ized in that between the outermost layer of polyamide and the sequence of at least four intermediate layers in each case based on adhesion promoter, polyolefin, polyolefin, adhesion promoter, at least two further layers are each arranged on the basis of polyamide or ethylene-vinyl alcohol copolymer or adhesion promoter, which from outside to inside preferably either a layer having an ethylene-vinyl alcohol copolymer as a layer constituent, and a layer having a polyamide as a layer constituent, or preferably a layer having a primer as a layer component, a layer having an ethylene-vinyl alcohol copolymer as a layer component, and a layer having a polyamide as a layer component.

6. Multilayer, tubular food film, in particular sausage casing, wherein the food film is fed by means of a blow head onto a multilayer coextrusion blown film system. ter, coextruded plastics and is stretched in the triple-bubble process and biaxially stretched, characterized in that the food film has at least six layers, wherein the layers of the food casing are arranged in a sequence from outside to inside as follows: a first layer from the outside with a polyamide as a layer component; a second layer from the outside with an adhesion promoter as a layer component; a third layer from the outside with a polyolefin, preferably polypropylene, as a layer component; a fourth layer from the outside with a polyolefin, preferably polypropylene, as a layer component; a fifth layer from the outside with a bonding agent as a layer component; and a sixth layer from the outside with a polyamide as a layer component.

7. Multilayer, tubular food film, in particular sausage casing, wherein the food film is produced on a multilayer coextrusion blown film plant by means of a blow head supplied, coextruded plastics and in the triple-bubble process and biaxially stretched, characterized in that the food film having at least seven layers, the layers of food film being arranged in a sequence from outside to inside as follows: a first layer from the outside with a polyamide as a layer component; a second layer from the outside with a

Adhesion promoter as a layer component; - a third layer from the outside with a

Polyolefin, preferably polypropylene, as

Layer component; a fourth layer from the outside with a

Adhesion promoter as a layer component; - a fifth layer from the outside with a

Polyolefin, preferably polypropylene, as

Layer component; a sixth layer from the outside with a

Adhesion promoter as a layer component; and - a seventh layer from the outside with a

Polyamide as a coating component.

8. Multilayer, tubular foodstuff film, in particular a sausage casing, wherein the foodstuff film is produced on a multilayer coextrusion blown film plant by means of coextruded plastics supplied by a blow head and stretched in the triple bubble process and biaxially stretched, characterized in that the food sheet has at least eight layers, wherein the layers of the food film are arranged in a sequence from outside to inside as follows: a first layer from the outside with a polyamide as a layer component; a second layer from the outside with an ethylene-vinyl alcohol copolymer as a layer component; a third layer from the outside with a polyamide as a layer component; a fourth layer from the outside with an adhesion promoter as a layer component; - A fifth layer from the outside with a polyolefin, preferably polypropylene, as a layer component; a sixth layer from the outside with a polyolefin, preferably polypropylene, as a layer component; a seventh layer from the outside with an adhesion promoter as a layer component; and an eighth layer from the outside with a polyamide as a layer component.

9. Multilayer, tubular food film, in particular sausage casing, wherein the food film is produced on a multilayer coextrusion blown film plant by means of a blow head supplied coextruded plastics and in the triple-bubble process and biaxially stretched, characterized in that the food film comprising at least nine layers, wherein the layers of food film are arranged in a sequence from outside to inside as follows: a first layer from the outside with a polyamide as a layer component; - A second layer from the outside with an ethylene-vinyl alcohol copolymer as a layer component; a third layer from the outside with a polyamide as a layer component; a fourth layer from the outside with an adhesion promoter as a layer component; a fifth layer from the outside with a polyolefin, preferably polypropylene, as a layer component; a sixth layer from the outside with a bonding agent as a layer component; a seventh layer from the outside with a polyolefin, preferably polypropylene, as a layer component; an eighth layer from the outside with a bonding agent as a layer component; and a ninth layer from the outside with a polyamide as a layer component.

10. Multilayer, tubular food film, in particular sausage casing, wherein the food film is produced on a multi-layer coextrusion blown film plant by means of a blow head supplied coextruded plastics and in the triple-bubble process and biaxially stretched, characterized in that the food sheet has at least nine layers, wherein the layers of the food sheet are arranged in a sequence from outside to inside as follows: a first layer from the outside with a polyamide as a layer component; - A second layer from the outside with a primer as a layer component; a third layer from the outside with an ethylene-vinyl alcohol copolymer as a layer component; a fourth layer from the outside with a polyamide as a layer component; a fifth layer from the outside with a bonding agent as a layer component; - A sixth layer from the outside with a polyolefin, preferably polypropylene, as a layer component; a seventh layer from the outside with a polyolefin, preferably polypropylene, as a layer component; an eighth layer from the outside with a bonding agent as a layer component; and a ninth layer from the outside with a polyamide as a layer component.

11. Multilayer, tubular food film, in particular sausage casing, wherein the food film is produced on a multi-layer coextrusion blown film line by means of a coextruded plastic supplied by a blow head, and in the

Triple bubble method and biaxially stretched, characterized in that the food sheet has at least ten layers, wherein the layers of the food sheet are arranged in a sequence from outside to inside as follows: a first layer from the outside with a polyamide as a layer component; - a second layer from the outside with a

Adhesion promoter as a layer component; a third layer from the outside with an ethylene-vinyl alcohol copolymer as a layer component; a fourth layer from the outside with a

Polyamide as a layer component; a fifth layer from the outside with a

Adhesion promoter as a layer component; - a sixth layer from the outside with a

Polyolefin, preferably polypropylene, as

Layer component; a seventh layer from the outside with a

Adhesion promoter as a layer component; - an eighth layer from the outside with a

Polyolefin, preferably polypropylene, as

Layer component; a ninth layer from the outside with a

Adhesion promoter as a layer component; and - a tenth layer from the outside with one

Polyamide as a coating component.

12. Multilayer, tubular food film, in particular sausage casing, wherein the foodstuff film is produced on a multilayer coextrusion blown film plant by means of coextruded plastics fed to a blow head and stretched in the triple-bubble process and biaxially, characterized in that the food sheet has at least nine layers, wherein the layers of the food sheet are arranged in a sequence from the outside to the inside as follows: a first layer from outside with a polyamide as a layer component; a second layer from the outside with an adhesion promoter as a layer component; a third layer from the outside with a polyolefin, preferably polypropylene, as a layer component; a fourth layer from the outside with an adhesion promoter as a layer component; a fifth layer from the outside with an ethylene-vinyl alcohol copolymer as a layer component; a sixth layer from the outside with a bonding agent as a layer component; a seventh layer from the outside with a polyolefin, preferably polypropylene, as a layer component; an eighth layer from the outside with an adhesion promoter as a layer constituent; and a ninth layer from the outside with a polyamide as a layer component.

13. Multilayer tubular food film, in particular sausage casing, wherein the food film is produced on a multilayer coextrusion blown film plant by means of a blow head supplied, coextruded plastics and stretched in a triple-bubble process and biaxially, characterized in that the food film comprising at least eleven layers, wherein the layers of food film are arranged in a sequence from outside to inside as follows: a first layer from the outside with a polyamide as a layer constituent; a second layer from the outside with an adhesion promoter as a layer component; a third layer from the outside with a polyolefin, preferably polypropylene, as a layer component; a fourth layer from the outside with an adhesion promoter as a layer component; a fifth layer from the outside with a

Polyamide as a layer component; a sixth layer from the outside with a

Ethylene-vinyl alcohol copolymer as a layer constituent; a seventh layer from the outside with a

Polyamide as a layer component; an eighth layer from the outside with a bonding agent as a layer component; - a ninth layer from the outside with a

Polyolefin, preferably polypropylene, as

Layer component; a tenth layer from the outside with one

Adhesion promoter as a layer component; and - an eleventh layer from the outside with a polyamide as a layer component.

14. The multilayer, tubular food wrap according to claim 1, characterized in that the increase in the brightness of the dyed foodstuff foil ranges from 5 to 20%, preferably from 6 to 15%, in particular from 7 to 10%, and / or the increase in brilliance of the colored food sheet is in the range of 8 to 30%, preferably 9 to 25%, especially 10 to 15%, over a 5-layer standard film.

15. Multilayer, tubular foodstuff film according to at least one of claims 1 to 14, characterized characterized in that the shrinkage of the food sheet is in the range of 5 to 30%, preferably 12 to 15%.

16. A multilayer, tubular food wrap according to at least one of claims 1 to 15, characterized in that the overstretching factor of the food wrap is in the range of 2 to 20%, preferably 10 to 12%.

17. Multilayer, tubular foodstuff film according to claim 1, wherein the oxygen permeability of the foodstuff film is less than 10 cm ³ / (m ² «day bar), preferably less than or equal to 3 cm ³ / (m ² Day bar) at 23 ⁰ C and 0% relative humidity and / or less than or equal to 9 cm ³ / (m ² day bar) at 23 ⁰ C and 85% relative humidity, is.

18. Multilayer, tubular food film according to at least one of claims 1 to 17, characterized in that the water vapor permeability of the food film is less than 3 g / (m ² -day bar), in particular in the range from about 1.5 to 2.5 g / (na ² tag bar) at 23 ^° C. and 50% relative humidity.

19. Multilayer, sheet-like food casing, produced from a cut-open, multilayer, tubular food film according to at least one of claims 1 to 18.