WO2009049667A1 - Multi-layer film and method for the production thereof - Google Patents

Multi-layer film and method for the production thereof Download PDF

Info

Publication number
WO2009049667A1
WO2009049667A1 PCT/EP2007/060984 EP2007060984W WO2009049667A1 WO 2009049667 A1 WO2009049667 A1 WO 2009049667A1 EP 2007060984 W EP2007060984 W EP 2007060984W WO 2009049667 A1 WO2009049667 A1 WO 2009049667A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
layer
film
characterized
multilayer film
preceding
Prior art date
Application number
PCT/EP2007/060984
Other languages
German (de)
French (fr)
Inventor
Harald Schmidt
Christoph Hess
Johannes Mathar
Ralf Hackfort
Original Assignee
Biotec Biologische Naturverpackungen Gmbh & Co. Kg
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00Layered products comprising a layer of synthetic resin
    • B32B27/36Layered products comprising a layer of synthetic resin comprising polyesters
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B23/00Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose
    • B32B23/04Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising such cellulosic plastic substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B23/08Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising such cellulosic plastic substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00Layers arrangement
    • B32B2250/033 layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00Properties of the layers or laminate
    • B32B2307/50Properties of the layers or laminate having particular mechanical properties
    • B32B2307/54Yield strength; Tensile strength
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00Properties of the layers or laminate
    • B32B2307/70Other properties
    • B32B2307/724Permeability to gases, adsorption
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00Containers; Receptacles
    • B32B2439/70Food packaging

Abstract

The invention relates to a multi-layer film, particularly for packaging purposes, comprising at least one first layer A and at least one second layer B, layer A comprising thermoplastic polyester and layer B comprising thermoplastic starch, and layer B does not contain any additional biologically degradable, thermoplastic polymers other than thermoplastic starch. The multi-layer film according to the invention is characterized by excellent barrier properties, a low sensitivity to moisture, and a good mechanical durability.

Description

October 15, 2007

Multilayer film and processes for their preparation

The invention relates to a multilayer film, in particular for packaging purposes, comprising at least two layers A and B. The invention further relates to a method for producing the multilayer film and produced from this packaging materials.

Multilayer films of the type mentioned are generally known and are used for example for the packaging of food and other goods. For the packaging of oxygen-sensitive foods, it is also necessary that the films have a low oxygen permeability. Such films are also referred to as "barrier films". For example, they are used in the packaging of fresh meat and fruits and vegetables, whose durability can be significantly extended by specific adjustment of the gas barrier, in particular oxygen and / or water vapor barrier. The vast majority of the barrier films used in the packaging industry today consists of plastics derived from petrochemicals.

increasing economic and environmental considerations, there is a need for suitable films produced from renewable raw materials and / or are biodegradable.

The present invention therefore has for its object to provide a multilayer film of the type mentioned, which has good barrier properties and which produced from renewable raw materials and / or biodegradable. Further, the film should have sufficient mechanical strength and be moisture resistant and affordable beyond, and have a good transparency depending on the application.

This object is inventively achieved by a multi-layer film, especially for packaging purposes, comprising at least a first layer A and at least one second layer B, the layer A is at least one thermoplastic polyester and layer B contains thermoplastic starch.

Advantageous embodiments of the invention are described in the subclaims.

An essential feature of the multilayer film according to the invention that its layer structure contains one hand, thermoplastic polyester layer (layer A) and on the other hand, thermoplastic starch (layer B). It has surprisingly been found that multilayer films which contain this combination of materials having exceptionally good properties as packaging films.

The inventive films are characterized by excellent barrier properties and in particular have a low oxygen and carbon dioxide permeability. The films also have excellent mechanical strength as well as low moisture sensitivity. can if desired with the inventive layer structure further thermoformable films with excellent transparency manufacture.

The inventive multilayer film is characterized by excellent mechanical strength and can be suited for the production of packaging process. Thus, with the inventive layer structure, for example, tensile strength according to DIN 53455 in the range 10 to 40 N / mm 2, in particular 15 to 30 N / mm 2, to achieve.

The multilayer films of the invention are also distinguished by excellent barrier properties. Thus, preferably the multilayer film of the invention has an oxygen permeability according to ASTM F 1927-98 at 23 0 C, 50% rh and 400 microns film thickness of 1 to 50, in particular 1.5 to 20 cm 3 / m 2 d, more preferably 2 to 10 cm 3 / m 2 d. Further, the multilayer film of the invention preferably has a water vapor permeability according to ASTM F 1249 at 23 0 C, 75 RH and 400 microns film thickness of 1 to 100, in particular 2 to 10 cm 3 / m 2 d. Finally, preferably the multilayer film of the invention in particular 1 to 2.5 cm 3 / m 2 has a carbon dioxide permeability according to ASTM D 1434 at 23 0 C, 50 RH and 400 microns film thickness of 0.5 to 5, d. Due to the aforementioned barrier properties, the multilayer film of the invention is ideally suited as a barrier film for packaging purposes.

The multilayer film of the invention may have any thickness, the thickness of the film largely depends on the intended application and the desired film properties. For packaging purposes, preferably, the film has a total thickness of 10 to 2000 .mu.m, in particular 100 to 2000 .mu.m, more preferably 200 to 800 microns, on which the individual layers preferably each have a thickness of 5 to 1000 .mu.m, in particular 10 to 1000 microns, preferably still more preferably have 10 to 700 microns 20 to 700 microns. Blown film on the multilayered base preferably have a total thickness of 30 to 100 microns.

The packages produced from the novel multilayer films may have any thickness. preferably have from the novel multilayer films manufactured shells for food packaging has a total thickness of 350 to 400 .mu.m, the corresponding cover films preferably have a thickness of 30 to 100 microns.

The inventive multilayer film comprises at least one layer A and at least one layer B. In addition, the film of the invention may comprise any further layers. According to a particularly preferred embodiment of the invention, the inventive multilayer film comprises at least two layers A and a layer B, said layer B is preferably arranged between the two layers A. Such a multilayer film has the following layer structure: layer A - layer B - layer A.

In such a layer structure, the layer A may be directly adjacent to the layer B. However, it may also be provided one or more additional layers as an intermediate layer, such as one or more adhesive layers H. Such adhesive layers H are known in the art and are preferably composed of block copolymer. The adhesion promoter layer H bordering on its one surface side is preferably directly on the layer A and on its other side surface directly to the layer B and to improve the adhesion between the layers A and B. As an example for an inventive multi-layer film is used comprising adhesive layers following layer structure can be specified be: layer A - adhesive layer H - layer B - adhesive layer H - layer A.

Depending on the intended application, the film may include further layers A and / or B. is possible, for example a multilayer film having the following layer structure: layer A - layer B - layer A - layer B - layer A. Due to the double layer B provided such a film has further improved barrier properties. Between the individual layers in addition, an adhesion promoter layer H be disposed. A ski cht

According to the invention it is provided that the layer A of the multilayer film contains at least one thermoplastic polyester. The selection of the thermoplastic polyester is not restricted. There are both aliphatic and aromatic, and their polyester copolymers and / or mixtures in question.

Thermoplastic polyesters are generally known and, for example, in upper Bach et al. described "Saechtling Plastics Handbook", 29th ed., Hanser-Verlag, Munich (2004).

According to a preferred embodiment of the invention, in which contained in the layer A thermoplastic polyester according to EN 13432 is a biologically abbaubareren thermoplastic polyester.

In particular, it may be the thermoplastic polyester is a biopolymer based on one or more hydroxycarboxylic acids.

According to the invention particularly suitable thermoplastic polyesters are poly [hydroxyalkanoates] (PHA), poly [alkylensuccinate] (PAS) such as

Poly [butylene succinate] (PBS), poly [alkylenterephtalate] (PAT) such as poly [ethylene terephthalate] thereof (PET), aliphatic-aromatic copolyesters and / or poly [p- dioxanone] (PPDO) and copolymers and mixtures thereof. Also conceivable is the use of Biopropandiol (Bio-PDO) - Polyester alone or in combination with other thermoplastic polyesters. According to a particularly preferred execution of the invention, layer A contains at least one poly [hydroxyalkanoate] (PHA) as a thermoplastic polyester. Examples of suitable poly [hydroxyalkanoates] are poly [hydroxyethanoat] such as polyglycolic acid (PGA), poly [hydroxypropanoate] such as polylactic acid or polylactide (PLA), poly [hydroxybutanoate] such as polyhydroxybutyrate (PHB), poly [hydroxypentanoate], such as polyhydroxyvalerate (PHV) and / or poly [hydroxyhexanoate] such as polycaprolactone (PCL), and copolymers and blends thereof.

A according to the invention particularly suitable thermoplastic polyester is polylactic acid or polylactide (PLA). PLA is a biodegradable polyester that can be prepared via a multi-step synthesis of sugar. Here sugar is fermented to lactic acid and these polymerized usually via the intermediate stage of the dilactide to PLA. PLA is transparent, crystalline, rigid, has high mechanical strength and can be processed by conventional thermoplastic methods. Suitable polymers based on PLA are described for example in the publications US 6,312,823, US 5,142,023, US 5,274,059, US 5,274,073, US 5,258,488, US 5,357,035, US 5,338,822 and US 5,359 026. According to the invention can be used both as virgin material as well as recycled material in the form of PLA.

A further particularly suitable thermoplastic polyester is polyhydroxybutyric acid (PHB). PHB is formed in nature from numerous bacteria as a storage and reserve substance. Accordingly, the industrial production of PHB by bacteria can occur. Suitable polymers based on PHB are described for example in the publications US 4,393,167, US 4,880,592 and US 5,391,423.

As a material for layer A of the present invention, in particular the "aliphatic polyester polymers" described in the publication US 6,312,823 are suitable, incorporated herein by reference to the description and which is made the subject matter of the present disclosure.

Suitable copolymers or mixtures of the said thermoplastic polyester are, for example, polycaprolactone / Polybutylensuccinatmischungen or copolymers (PCL / PBS), polyhydroxybutyric acid / Polyhydroxyvaleratcopolymere (PHB / PHV),

Polyhydroxybutyrate valerate (PHBV), polybutylene succinate / Polybutylenadipatmischungen or copolymers (PBS / PBA), polyethylene terephthalate / Polyethylensuccinatcopolymere (PET / PES) and / or polybutylene terephthalate / polybutylene adipatcopolymere (PBT / PBA).

A layer may contain additional components in addition to thermoplastic polyester. More specifically, the layer A can consist of a mixture of different polymers. A layer may contain conventional additives such as processing aids, plasticizers, stabilizers, anti-flame agents and / or fillers beyond. Further, a coupling agent may be added to the layer A, which can be used in particular for improving the adhesion between layer A and B. Preferably, layer A contains thermoplastic polyester in an amount of at least 20 wt.%, In particular at least 30 wt.% Or at least 40 wt.%, More preferably at least 50 wt.% Or at least 60 wt.%, Even more preferably at least 80 wt. %, and most preferably at least 90 wt.%. or at least 95 wt.%, based on the total weight of layer A. More preferably, layer A consists substantially of thermoplastic polyester.

According to the invention usable processing aids are known to those skilled. In principle, all processing aids come of it in question, which are likely to improve the processing characteristics of the polymers used, in particular their flow behavior in the extruder.

According to the invention particularly suitable processing aids are polymers that have a polymer backbone (the backbone), which is functionalized with reactive groups or modified. Such polymers are also referred to as "functionalized polymer". The processing aids used in the invention preferably have a molecular weight of up to 200,000, especially up to 100,000.

As the polymer backbone (the backbone) of the processing aid are in principle all polymers which with at least one polymer component (for example PLA) at least one layer of the multilayer film (eg, layer A) are miscible. Possible polymer scaffolds for the processing aid, for example, ethylene vinyl acetate (EVA), polyethylene (PE), polypropylene (PP), ethylene acrylates, polyester (such as PLA), and mixtures and / or Copolyπiere (for example, polyethylene methyl acrylate copolymer or polyethylene-butyl acrylate copolymer) thereof ,

As reactive group of the inventively used processing aids in principle all reactive groups into consideration, which are capable of having at least one polymer component (for example, TPS) at least one layer of the multilayer film (eg, layer B) to chemically react. Suitable reactive groups are for example maleic anhydride and / or other anhydrides of suitable carboxylic acids or dicarboxylic acids or other polybasic acids. Preferably, the polymer backbone (the backbone) is present with reactive groups in an amount of 0.01 to 7 wt.%, Particularly 0.1 to 5 wt.%, More preferably 0.3 to 4 wt.%, Based on the total composition of the processing aid modified. Preferably, the reactive groups on the polymer backbone (the backbone) are grafted.

Such processing aids are, for example, under the trade names Lotader® and Orevac® (Arkema Inc., USA), Fusabond®, Biomax strong® and Bynel® (DuPont, USA) and Plexar® (Equistar Chemical Company, USA) is commercially available.

The processing aid is preferably used in an amount of up to 5.%, Particularly 0.01 to 2.%, More preferably 0.1 to 1.5 wt.%, More preferably 0.2 to 1 wt.%, And preferably in an amount of less than 1 wt.%, based on the total composition of each layer used. In a particularly preferred execution form of the invention is as a processing aid for layer A, a maleic anhydride-modifizierteε ethylene-based polymer, in particular a maleic anhydride-modified polyethylene alkyl acrylate copolymer employed.

According to the invention it has been found that not only is the processability of the polymers used in the extruder {flowability, homogeneity of the melt) can be improved by the use of said processing aids, but also a significantly improved adhesive bond between the layers can be achieved.

layer B

According to the invention it is further provided that layer B of the multilayer film contains thermoplastic starch.

Thermoplastic starch or thermoplastically processable starch (TPS) is generally known and for example in the publications EP 0,397,819 Bl, WO 91/16375 Al, EP 0537657 Bl and EP 0702698 Bl detail. With a market share of about 80 percent thermoplastic starch constitutes the most important and most commonly used representative of bioplastics. Thermoplastic starch is made of native starch such as potato starch in general. In order to make native starch melt-processable, their plasticizers such as sorbitol and / or glycerol are added. Thermoplastic starch is characterized by a low water content of, preferably less than 6 percent of.%, Based on the total weight of the thermoplastic starch, is. Further, thermoplastic starch is characterized by its preferably substantially amorphous structure.

As a thermoplastic starch, a polymeric material is preferably used which is obtainable by homogenizing a mixture comprising

- 40 to 85% by weight of starch and / or starch derivative.

- 15 to 55% by weight plasticizer.

Percent to less than about 12 under supplying thermal and / or mechanical energy, and adjusting the water content of the mixture.%.

The mixture may contain suitable additives, fillers and / or processing aid in addition to the main components of starch or starch derivative, a plasticizer and water, as described in more detail above in connection with layer A. According to a preferred execution form of the invention, the mixture contains no synthetic, according to EN 13432 biodegradable thermoplastic polymer. According to a further preferred embodiment, the mixture is added at all, no additional thermoplastic polymeric material. The total amount of additives contained in the mixture, and processing aids is preferably not more than 5 wt.%, Particularly not more than 3 wt.%, More preferably not more than 2 wt.%. As fillers, inorganic fillers are preferably used. a polymeric material is used insofar as an additive, filler and / or processing means, it is preferably not thermoplastic and / or not in accordance with EN 13432 biodegradable.

According to a preferred execution of the invention form containing the mixture for preparing the thermoplastic starch 45 to 80 wt.%, In particular 50 to 75 wt.%, Preferably 55 wt to 72.%, More preferably 58-70 wt.%, Most preferably 59 to 67 wt.% starch and / or starch derivative. Further, the mixture for preparing the thermoplastic starch contains preferably 20 to 50 wt.%, In particular 25 to 45 wt.%, Preferably 28 wt to 42.%, More preferably 30 to 40 and most preferably 35 to 38 wt.% Plasticizer.

The thickness or used in the manufacture of thermoplastic starch, the starch derivative are preferably selected from native potato starch, tapioca starch, rice starch and corn starch.

The plasticizer or the plasticizer for the preparation of the thermoplastic starch is preferably selected from the group consisting of ethylene glycol, propylene glycol, glycerol, 1, 4-propanediol, 1, 2-butanediol, 1,3-butanediol, 1, 4-butanediol, 1 , 5-pentanediol, 1,5- hexanediol, 1, 6-hexanediol, 1, 2, 6-hexanetriol, 1,3,5-hexanetriol, neopentylglycol, sorbitol acetate, Sorbitdiacetat, Sorbitmonoethoxylat, Sorbitdiethoxylat, Sorbithexaethoxylat, Sorbitdipropoxylat, aminosorbitol, trihydroxymethylaminomethane , glucose / PEG, the reaction product of ethylene oxide with glucose, Trimethylolpropanmonoethoxylat, Mannitmonoacetat, Mannitmonoethoxylat, butyl glucoside, Glucosemonoethoxylat, α-methyl glucoside, the sodium salt of

Carboxymethylsorbit, Polyglycerinmonoethoxylat, erythritol, pentaerythritol, arabitol, adonitol, XyIit, mannitol, iditol, galactitol, AlIit, sorbitol, polyhydric alcohols generally, Glycerinester, formamide, N-methylformamide, DMSO, mono- and diglycerides, alkylamides, polyols, trimethylolpropane, polyvinyl alcohol having 3 to 20 repeating units, polyglycerols with from 2 to 10 repeating units and derivatives and / or mixtures thereof. The plasticizer preferably also has a solubility parameter (HiIdebrand parameters) d (SI) of 30 - 50 MPa 1 '' 2 within a temperature range of about 150 to 300 0 C. Particularly suitable plasticizers are glycerol and / or sorbitol.

According to a preferred execution of the invention, layer B is obtained by at least partially by weight of thermoplastically processable starch having a water content of less than 6%, preferably less than 5 wt%, especially less than 4.5 wt%...; more preferably less than 4 wt.%, based on the total composition of the starch starts.

In the manufacture of the thermoplastic starch, the water content of the mixture is preferably used at 0.5 to 12.% By weight, especially 1 to 7.%, More preferably 1 to 6 wt.%, More preferably 1.5 to 4.5 wt. set%, based on the total composition of the thermoplastically processable starch. _ 1 ζ

It has been found that (weight, in particular <6.%) With the use of thermoplastically processable starch with the specified water contents improved flow behavior in the extruder, and reduced formation of microbubbles in the layer can be achieved.

Preferably, however, the thermoplastically processable starch used has a water content of at least 1 wt.%, particularly at least 1.5 wt.%, since it thereby may lead to undesirable discoloration of the product otherwise easy to thermally induced oxidation processes and accompanied. Conversely, it may at a water content greater than about 6 wt.% Easily lead to an increased formation of microbubbles, which is also undesirable.

The homogenization of the starch-containing mixture in the preparation of the thermoplastic starch is preferably carried out by the action of shear forces on the mixture. Suitable homogenization, for example, dispersing, stirring, kneading and / or extruding. According to a particularly preferred embodiment of the invention, the homogenization is carried out by extruding the mixture in an extruder. During homogenization or extruding the mixture is preferably heated to a temperature of 90 to 200 0 C, in particular 120 to 180 0 C, more preferably 130 to 160 0 C, is heated. The water content of the mixture is preferably adjusted during homogenization or extrusion. The adjustment of the water content can, for example, by degassing the mixture, in particular by degassing the melt take place. The thermoplastic starch present in layer B is preferably characterized in that a film made of the thermoplastic starch has a tensile strength according to DIN 53455 2-10 N / mm 2, particularly from 4 to 8 N / mm 2 'and / or an elongation at break in accordance with DIN 53455 of 80 to 200%, in particular from 120 to 180%, having.

According to another preferred embodiment of the invention, the thermoplastic starch is obtainable by: (a) mixing starch and / or a starch derivative by weight of at least 15% of a plasticizer such as glycerin and / or sorbitol, (b) supplying thermal and /. or mechanical energy, and (c) contains at least partially removing the natural water content of the starch or starch derivative to a water content of less than 6.%.

Layer B may contain additional components in addition to thermoplastic starch. In particular, layer B conventional additives such as plasticizers, processing aids, stabilizers, anti-flame agents and / or fillers, as described above for layer A, included. In particular, layer B can contain suitable processing aids, as described in more detail above in connection with layer A. Further, the layer B, a bonding agent can be added which may serve to improve the adhesion between layer B and A. Unless it is in the B layer contained in other components of polymeric materials, these are preferably non-thermoplastic, and / or not in accordance with EN 13432 biodegradable.

Preferably, layer B contains thermoplastic starch in an amount of at least 80 wt.%, And most preferably at least 90 wt.%., At least 90.5 wt.% Or at least 95 wt.%, Based on the total weight of layer B. More preferably, layer B consists substantially of thermoplastic starch, ie it does not is a starch blend of starch and one or more other polymers, but exclusively thermoplastic starch. According to a preferred embodiment of the invention, layer B, therefore, in addition to thermoplastic starch no further in accordance with EN 13432 biodegradable thermoplastic polymers. According to a further preferred embodiment, layer B next to thermoplastic starch no further thermoplastic polymers.

According to one embodiment of the invention form consist of both layer A and layer B consists essentially of thermoplastic polyester and thermoplastic starch.

An inventively particularly preferred

The multilayer film is a three layer film of the ABA type, wherein layer A of a polymer based on PHA (particularly PLA) and layer B consists of a polymer based on thermoplastic starch.

The production of the multilayer film of the invention can be prepared by any production method such as calendering, extrusion or by casting. Such manufacturing processes are generally known in the art and, for example, in J. Nentwig, "Plastic Films", 2nd Ed., Hanser Verlag, Berlin (2000), pages 39-63.

Preferably, multilayer films of the invention are prepared by extrusion, in particular by blown film extrusion, flat film extrusion, cast-film extrusion and / or blow formed. These methods of preparation are known to those skilled. A detailed description of this manufacturing method, "Plastic Films" is found for example in J. Nentwig, 2nd ed., Hanser Verlag, Berlin (2000), pp 45 to 60, to which express reference is made and made the subject of the present disclosure becomes. The preparation examples described therein are also applicable to the production of the multilayer film of the invention. Both single and all layers of the film can be formed by extrusion. Preferably, all layers of the film are formed by extrusion.

According to a particularly preferred embodiment of the invention, the inventive multilayer film is formed by coextrusion. Such co-extrusion or multilayer extrusion method generally known to those skilled. A description of the co-extrusion method, "Plastic Films" is found for example in J. Nentwig, 2nd ed., Hanser Verlag, Berlin (2000), pages 58 to 60 to which explicitly reference is made, and an object of the present disclosure is made. The preparation examples described therein are also applicable to the production of the multilayer film of the invention.

Accordingly, the present invention relates to a process for the production of a multilayer film, the multilayer film at least one layer A, at least one layer B, and optionally further layers, in particular optionally at least one further layer A, characterized by the following steps:

(A) extruding a material containing at least one thermoplastic polyester to form a film, whereby at least one layer A is formed;

(B) extruding a material containing thermoplastically processable starch to form a film, whereby at least one layer B is formed; and

(C) at least partially flat connection of the individual layers, whereby a multilayer film is formed.

The individual process steps (a) to cc) are preferably carried out simultaneously by the coextrusion process, in particular by blown film extrusion, flat film extrusion, cast-film extrusion and / or blow molding.

After their manufacture, the multilayer film can be cut depending on the application in parts having the desired dimensions. The accumulating section when cutting radicals can at least partially the material for extruding layer B in step (b) are fed, and thus serve as a recycled material.

Finally, the invention relates to a packaging for foodstuffs, in particular for fresh meat, cheese, fresh fruit or vegetables, baked goods, beverages and / or coffee, comprising the multilayer film of the invention.

The invention will be described in more detail with reference to embodiments.

The single figure shows an example of a sectional view of a multilayer film of the invention having a layer construction of the type ABA.

example 1

Preparation of thermoplastic starch for the middle layer (layer B)

A mixture of native potato starch (63 wt.%), Glycerol (23 wt.%) And sorbitol (14 wt.%) Was introduced into a twin-screw extruder. The mixture was intensively mixed in the extruder in a temperature range of 130 to 16O 0 C, wherein the melt was simultaneously degassed in order to the mixture to remove water. This results in a homogeneous melt which can be drawn off and granulated. The water content of the homogenised in the manner described, thermoplastically processible mass is weight 3 to 4%. By mixing and homogenizing of the native starch with glycerine and sorbitol crystalline structures of the starch are broken, so that the resulting thermoplastic starch is substantially amorphous. By contrast, has destructured starch, which may be made of native starch for example by heating in water, still has a certain crystallinity.

example 2

Producing a three-layer film (flat sheet)

was prepared a three layer film (ABA), consisting of polylactic acid (PLA) / thermoplastic starch (TPS) / PLA. Starch% was prepared in the Embodiment 1, by weight thermoplastic glycerine / sorbitol starch having a water content of 3 to 4 is used. The polylactic acid used (PLA granulate, Nature Works) had a D-content of 1.4%.

The two materials (PLA and TPS) were run simultaneously in a co-extrusion to the three-layer film. For this, the TPS was melted in a single screw extruder with a L / D ratio of 33 at a temperature range of 140 to 19O 0 C. The extruder was run at a speed of 100 rev / min and produced, with a throughput of 25 kg / h, a melt pressure of 130 bar. In parallel, a second single-screw extruder was (L / D = 30, temperature 200 0 C, speed 20 rev / min, melt pressure 100 bar, throughput 10 kg / h) PLA melted (melt temperature 177 0 C). Both melts were combined in a coextrusion adapter that was being shared the PLA melt flow and conducted half above and below the starch layer (-> outer layers A). The three-layer system produced in this way was drawn off through a slit die (T = 190 0 C) by means of temperature-controllable rollers (T = 25 0 C, V = 3 m / min), cut to width, and wound into a roll.

The total thickness of 400 microns the three-layer film thus produced is composed of 2 x 50 m (outer layers A) and 300 microns (middle layer B).

For the three-layer film the following gas permeabilities were determined:

Oxygen (O 2): 15.5 cπvVm 2 d carbon dioxide (CO 2): 2.1 cm 3 / m 2 d

example 3

Producing a three-layer film according to Embodiment 2 premixed middle layer (layer B)

Analogous to that described in Working Example 2, a three layer film ABA with PLA as the outer layer (A) was prepared. For the middle layer (B) a premix of the according to Embodiment 1 produced TPS granules (90 wt.%) And PLA-granulate (% 10 wt.), Prepared supplied to the single-screw extruder and melted at 150 to 19O 0 C. The extruder for the middle layer ran with 100 U / min at a throughput of 25 kg / h and a melt pressure of 120 bar. PLA melted (melt temperature 175 0 C) - parallel to this was in the second single-screw extruder (flow rate 10 kg / h 200 0 C, speed 20 rev / min, melt pressure 130 bar, temperature 185). Both melts were combined in the coex adapter, which split as described in Example 2, the PLA melt flow and was conducted half above and below the starch layer (-> outer layers A). The three-layer system produced in this way was drawn off through a slit die (T = 19O 0 C) by means of temperature-controllable rollers (T = 35 ° C, V = 2.7 m / min), cut to width, and wound into a roll.

The total thickness of 400 microns the three-layer film thus produced is composed of 2 x 50 m (outer layers A) and 300 microns (middle layer B).

The three-layer film showed more compared with Embodiment 2 fogging, but a more stable compared to Embodiment 2 bond between the outer layers (A) and the middle layer (B) was obtained.

example 4

Production of a modified thermoplastic starch for the middle layer (layer B)

A mixture of native potato starch (56.5 wt.%), Glycerol (20.5%), sorbitol (13%) and PLA (10%) was charged into a twin-screw extruder. The mixture was intensively mixed in the extruder in a temperature range of 130 to 16O 0 C, wherein the melt was simultaneously degassed in order to the mixture to remove water. Similarly as in Embodiment 1, a homogeneous melt which can be drawn off and granulated. The water content of the homogenised in the manner described, thermoplastically processible mass is between 3 and 4% by weight.

example 5

Producing a three-layer film in accordance with Example 2 with a modified thermoplastic starch in the middle layer (layer B)

Analogous to that described in Application Examples 2 and 3 approach, a three-layer film ABA with PLA as the outer layer (A) was prepared. For the middle layer (B) of the starch / PLA compound described in Embodiment 4, thermoplastically processable was fed to the extruder and melted at 140-195 0 C. The extruder for the middle layer was 90 U / min at a throughput of 25 kg / h and a Maεεedruck of 115 bar.

Parallel to this was in the second single-shaft extruder (temperature 190-200 0 C, speed 25 rev / min, melt pressure

120 bar, throughput 10 kg / h) PLA melted (melt temperature 180 0 C).

Both melts were combined in the coex adapter, which split as described in the examples 2 and 3, the PLA melt flow and was conducted half above and below the starch layer (-> outer layers A). The three-layer system produced in this way was drawn off through a slit die (T = 185 ° C) by means of temperature-controllable rollers (T = 35 ° C, V = 3.1 m / min), cut to width, and wound into a roll.

The total thickness of 400 microns the three-layer film thus produced is composed of 2 x 50 m (outer layers A) and 300 microns (middle layer B).

The three-layer film showed stronger clouding a manufactured compared to the in accordance with embodiments 2 and 3 patterns, however, in comparison to the exemplary embodiments 2 and 3, stable composite between the outer layers A and the middle layer B was obtained.

example 6

As Example 2, however, the polylactic acid (PLA) for the outer layer was a weight with approximately 3 minutes.% Maleic anhydride functionalized ethylene / methyl acrylate polymer present in an amount of from about. 1%, based on the

Total composition of the PLA layer, was added. The three-layer film thus obtained had an increased compared to that described in Example 2 Product bond between the individual layers.

example 7

Producing a three-layer film (blown film) Made was a three-layer film (ABA) consisting of polylactic acid (PLA) / thermoplastic starch (TPS) / PLA. Starch% was prepared in the Embodiment 1, by weight thermoplastic glycerine / sorbitol starch having a water content of 3 to 4 is used. The polylactic acid used (PLA granulate, Nature Works) had a D-content of 1.4%.

The two materials (PLA and TPS) were run simultaneously in a co-extrusion to the three-layer film. For this, the TPS was in a single-screw extruder (Dr. Collin 0 45 x 25 D) are melted in a temperature range of 140 to 160 0 C. The extruder ran at a speed of 20 rev / min and produced, with a throughput of about 7 kg / h, a melt pressure of 130 bar. In parallel, in a second single-shaft extruder (Dr. Collin 0 30 x 25 D, temperature 160-190 0 C, speed 60 rev / min, melt pressure 140 bar, throughput 15 kg / h) was melted PLA. Both melts were (1.1 mm Dreischichtblasdüse 0 80 mm annular gap) were combined in an annular die, having been divided the PLA melt flow and conducted half above and below the starch layer (-> outer layers A). The three-layer system produced in this way was measured with a blow-up ratio of 3.5 and a speed of about 4.5 m / min as a tube with a total film thickness of about 50 microns and a flat width of 325 mm depending on a chrome and rubber roller (width per 400 mm) taken off and wound into a roll. The percentage thickness ratio of the multi-layer film ABA obtained was found to be 20-60-20. example 8

As Example 7, however, the polylactic acid (PLA) for the outer layer% maleic anhydride functionalized ethylene / methyl acrylate polymer was a weight having about the third in an amount of from about. 1%, based on the overall composition of the PLA layer, added , The three-layer film thus obtained had an increased compared to that described in Example 7 Product bond between the individual layers.

example 9

As in Example 8, however, the polylactic acid (PLA) for the outer layer additionally contains 5 wt.% Of, based on the total composition of the PLA layer, aliphatic / aromatic copolyester (ECOFLEX® BASF AG) was added. The system thus obtained had a better compared to the formulation of Example 13 workability.

example 10

Procedure according to Example 7, but was prepared a weight according to Embodiment 1 thermoplastic glycerine / sorbitol starch with a water content of about 2.5.% By weight. The system thus obtained had improved processability in the extruder and less bubble formation in the middle layer with respect to Example 7. FIG. The invention has been described above by means of exemplary embodiments by way of example. It should be understood that the invention is not limited to the embodiments described. Rather, will occur to those skilled in the art within the scope of the invention diverse possibilities Abwandlungs- and modification and the scope of the invention will be particularly defined by the following claims.

Claims

October 15 2007Patentansprüche
1. A multilayer film, in particular for packaging purposes, comprising at least one first layer A and at least one second layer B, wherein layer A contains B thermoplastic starch thermoplastic polyester and the layer, whereby in addition to thermoplastic starch, the layer B contains no more biodegradable thermoplastic polymer.
2. A multilayer film according to claim 1, characterized in that the thermoplastic polyester contained in layer A according to EN 13432 is a biodegradable thermoplastic polyester.
3. The multilayer film of any of the preceding claims, characterized in that the thermoplastic polyester is a biopolymer based on one or more polyhydroxy carboxylic acids.
4. The multilayer film of any preceding claim, characterized in that the thermoplastic polyester is selected from the group consisting of poly [hydroxalkanoaten] (PHA), poly [alkylensuccinaten] (PAS) such as poly [butylene succinate] (PBS),
Poly [alkylenterephtalaten] (PAT) such as poly [ethylene terephthalate (PET), aliphatic-aromatic copolyesters and poly [p-dioxanone] (PPDO) as well as copolymers thereof and mixtures thereof.
5. A multilayer film according to claim 4, characterized in that the poly [hydroxalkanoat] is selected (PHA) from the group consisting of
Poly [hydroxyethanoat] (for example polyglycolic acid, PGA), poly [hydroxypropanoate] (for example polylactic acid, polylactide, PLA), poly [hydroxybutanoate] (for example polyhydroxy butanoic acid, PHB), poly [hydroxypentanoate] (for example polyhydroxyvalerate, PHV) and poly [hydroxyhexanoate] (for example polycaprolactone, PCL), and copolymers and mixtures thereof.
6. The multilayer film of any preceding claim, characterized in that the layer B is obtained at least in part from thermoplastically processable starch having a water content of less than 6 wt.%, Preferably less than 3 wt.%, Based on the
Total composition of the starch.
7. The multilayer film of any preceding claim, characterized in that the layer B contains a thermoplastic starch which is characterized in that a film manufactured from the thermoplastic starch has a tensile strength according to DIN 53455 of 2 to 10 N / mm 2, in particular of 4 to 8 N / mm 2 'and / or an elongation at break according to DIN 53455 of 80 to 200%, in particular from 120 to 180%, having.
8. The multilayer film of any of the preceding claims, characterized in that the thermoplastic starch is obtainable by weight by (a) mixing starch and / or a starch derivative with at least 15 °.% Of a plasticizer such as glycerin and / or sorbitol, (b) supplying thermal and / or mechanical energy, and
(C) contains at least partially removing the natural water content of the starch or starch derivative to a water content of less than 6.%.
9. The multilayer film of any of the preceding claims, characterized in that layer A consists substantially of thermoplastic polyester and / or layer B consists essentially of thermoplastic starch.
10. The multilayer film of any of the preceding
Claims, characterized in that the film has a total thickness of 100 to 2000 .mu.m, in particular 200 to 800 microns.
11. The multilayer film of any preceding claim, characterized in that the individual layers each have a thickness of 10 to 1000 .mu.m, in particular 10 to 700 microns.
12. The multilayer film of any of the preceding claims, characterized in that the film has a three-layer film with the following layer structure is: layer A - layer B - layer A.
13. The multilayer film of any of the preceding claims, characterized in that, provided between the layer A and the layer B is at least an adhesive layer H, in particular an adhesive layer H of block copolymer.
14. The multilayer film of any of the preceding claims, characterized in that the film has a three-layer film with the following layer structure is: layer A - adhesive layer H - layer B - adhesive layer H - layer A.
15. The multilayer film of any of the preceding claims, characterized in that the film has a tensile strength according to DIN 53455 of 10 to 40, particularly 15 to 30 N / mm 2.
16. The multilayer film of Einein of the preceding claims, characterized in that the film has an oxygen permeability according to ASTM F 1927-98 at 23 ° C, 50% RH and 400 microns film thickness of 1 to 50, in particular 1.5 to 20 cm 3 / m 2 d having.
17. The multilayer film of any of the preceding claims, characterized in that the film has a water vapor permeability according to ASTM F 1249 at 23 ° C, 75 RH and 400 microns film thickness of 1 to 100, in particular 2 to 10 cm 3 / m 2 d.
18. The multilayer film of any of the preceding claims, characterized in that the film has a carbon dioxide permeability according to ASTM D 1434 at 23 ° C, 50 RH and 400 microns film thickness of 0.5 to 5, in particular 1 to 2.5 cm 3 / m 2 d has.
19. The multilayer film of any of the preceding claims, characterized in that at least one layer of the film by extrusion, in particular by blown film extrusion, flat film extrusion, cast-film extrusion and / or blow molding, is formed.
20. The multilayer film of any of the preceding claims, characterized in that all layers of the film by extrusion, in particular by blown film extrusion, flat film extrusion and / or blow molding, is formed.
21. The multilayer film of any preceding claim, characterized in that the film is formed by coextrusion.
22. A method for producing a multilayer film according to any one of the preceding claims, wherein the multilayer film comprises at least one layer A, at least one layer B, and optionally further layers, in particular optionally at least one further layer A umfaεst, characterized by:
(A) extruding a material containing at least one thermoplastic polyester to form a film, whereby at least one layer A is formed;
(B) extruding a material containing thermoplastically processable starch to form a film, whereby at least one layer B is formed; and
(C) at least partially flat connection of the individual layers, whereby a multilayer film is formed.
23. The method according to claim 22, characterized in that the method steps (a) through (c) are performed simultaneously by the coextrusion process, in particular by blown film extrusion,
Flat film extrusion, cast-film extrusion and / or blow molds,
24. The method of claim 22 or 23, characterized in that the multilayer film is cut depending on the application after their production in parts of the desired dimensions.
25. The method according to claim 24, characterized in that the accumulating section when cutting radicals is at least partly supplied to the material for extruding layer B in step (b).
26. Packaging for food, in particular for fresh meat, baked goods, cheese, fresh fruit or vegetables, beverages and / or coffee, comprising a multilayer film according to any one of claims 1 to 24 hours.
PCT/EP2007/060984 2007-10-15 2007-10-15 Multi-layer film and method for the production thereof WO2009049667A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2007/060984 WO2009049667A1 (en) 2007-10-15 2007-10-15 Multi-layer film and method for the production thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2007/060984 WO2009049667A1 (en) 2007-10-15 2007-10-15 Multi-layer film and method for the production thereof

Publications (1)

Publication Number Publication Date
WO2009049667A1 true true WO2009049667A1 (en) 2009-04-23

Family

ID=38711176

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2007/060984 WO2009049667A1 (en) 2007-10-15 2007-10-15 Multi-layer film and method for the production thereof

Country Status (1)

Country Link
WO (1) WO2009049667A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2959495A1 (en) * 2010-04-30 2011-11-04 Gascogne Sack Film for plastic bag e.g. biodegradable bag, to protect products from moisture, has inner layer comprising welding biopolymer that is fabricated from potato flour or starch, and adhesive layer formed between outer layer and inner layer
WO2016079244A1 (en) * 2014-11-19 2016-05-26 Bio-Tec Biologische Naturverpackungen Gmbh & Co. Kg Biodegradable multi-layer film

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2791603A1 (en) * 1999-04-01 2000-10-06 Ard Sa Water-resistant biodegradable composite material useful for making containers comprises a core of thermoplastic starch and a shell of a biodegradable polymer having a low melting point and a high viscosity
US20030108701A1 (en) * 2001-10-19 2003-06-12 The Procter & Gamble Company Polyhydroxyalkanoate copolymer/starch compositions for laminates and films
WO2004052646A1 (en) * 2002-12-09 2004-06-24 Biop Biopolymer Technologies Ag Biodegradable multi-layer film
WO2007118828A1 (en) * 2006-04-14 2007-10-25 Biotec Biologische Naturverpackungen Gmbh & Co. Kg Multilayered film and method for manufacturing same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2791603A1 (en) * 1999-04-01 2000-10-06 Ard Sa Water-resistant biodegradable composite material useful for making containers comprises a core of thermoplastic starch and a shell of a biodegradable polymer having a low melting point and a high viscosity
US20030108701A1 (en) * 2001-10-19 2003-06-12 The Procter & Gamble Company Polyhydroxyalkanoate copolymer/starch compositions for laminates and films
WO2004052646A1 (en) * 2002-12-09 2004-06-24 Biop Biopolymer Technologies Ag Biodegradable multi-layer film
WO2007118828A1 (en) * 2006-04-14 2007-10-25 Biotec Biologische Naturverpackungen Gmbh & Co. Kg Multilayered film and method for manufacturing same

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DATABASE COMPENDEX [online] ENGINEERING INFORMATION, INC., NEW YORK, NY, US; WANG L ET AL: "Preparation and properties of thermoplastic starch-polyester laminate sheets by coextrusion", XP002475549, Database accession no. E2000215126856 *
OLIVIER MARTIN, EMMANUELLE SCHWACH, LUC AVÉROUS , YVES COUTURIER: "Properties of Biodegradable Multilayer Films Based on Plasticized Wheat Starch", STARCH/STÄRKE, vol. 53, no. 8, 21 August 2001 (2001-08-21), Weinheim, DE, pages 372 - 380, XP002475548 *
POLYM ENG SCI; POLYMER ENGINEERING AND SCIENCE FEB 2000 SOC PLAST ENG, BROOKFIELD, CT, USA, vol. 40, no. 2, February 2000 (2000-02-01), pages 499 - 506 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2959495A1 (en) * 2010-04-30 2011-11-04 Gascogne Sack Film for plastic bag e.g. biodegradable bag, to protect products from moisture, has inner layer comprising welding biopolymer that is fabricated from potato flour or starch, and adhesive layer formed between outer layer and inner layer
WO2016079244A1 (en) * 2014-11-19 2016-05-26 Bio-Tec Biologische Naturverpackungen Gmbh & Co. Kg Biodegradable multi-layer film
JP2018504292A (en) * 2014-11-19 2018-02-15 バイオ−テック ビオローギッシュ ナチューフェアパックンゲン ゲーエムベーハー ウント コンパニ カーゲー Biodegradable multilayer film

Similar Documents

Publication Publication Date Title
US7358325B2 (en) Sulfonated aromatic copolyesters containing hydroxyalkanoic acid groups and shaped articles produced therefrom
Martin et al. Properties of biodegradable multilayer films based on plasticized wheat starch
US7193029B2 (en) Sulfonated copolyetherester compositions from hydroxyalkanoic acids and shaped articles produced therefrom
US6869985B2 (en) Environmentally friendly polylactide-based composite formulations
US7354656B2 (en) Floor covering made from an environmentally friendly polylactide-based composite formulation
US7678444B2 (en) Thermoformed article made from renewable polymer and heat-resistant polymer
US7132490B2 (en) Lactic acid-based resin composition
US20060009611A1 (en) Copolyetherester compositions containing hydroxyalkanoic acids and shaped articles produced therefrom
US20090324917A1 (en) Biodegradable Packaging Film
US6841597B2 (en) Ternary mixture of biodegradable polyesters and products obtained therefrom
US5849374A (en) Compostable multilayer structures, methods for manufacture, and articles prepared therefrom
US20080071018A1 (en) Toughened Poly(hydroxyalkanoic acid) Compositions
US7854994B2 (en) Barrier film
US6312823B1 (en) Compostable multilayer structures, methods for manufacture and articles prepared therefrom
WO2002059201A1 (en) Binary mixtures of biodegradable aliphatic polyesters and products obtained from these
WO2011080623A2 (en) Natural biopolymer thermoplastic films
US7067596B2 (en) Ternary mixtures of biodegradable polyesters and products manufactured from them
US6787613B2 (en) Ternary mixture of biodegradable polyesters and products obtained therefrom
US20090274920A1 (en) Thermoformed Article Made From Bio-Based Biodegradable Polymer Composition
WO2010034712A1 (en) Method for coating paper
US20070042207A1 (en) Biodegradable multi-layer film
US20090017240A1 (en) Multilayer film structures comprising bio-based materials
US20080182113A1 (en) Composition Comprising Biopolymer
US20110028622A1 (en) Poly(hydroxyalkanoic acid) blown film
JP2005329557A (en) Multilayered film

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07821351

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase in:

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 07821351

Country of ref document: EP

Kind code of ref document: A1