EP3622010A1

EP3622010A1 - Biodegradable film for food packaging

Info

Publication number: EP3622010A1
Application number: EP18719595.3A
Authority: EP
Inventors: Peter PFUNDTNER; Joerg Auffermann; Carsten SINKEL; Gabriel Skupin; Robert Loos; Jerome LOHMANN; Norbert Effen
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2017-05-10
Filing date: 2018-05-02
Publication date: 2020-03-18
Also published as: WO2018206352A1; CN110914344A; CN110914344B

Abstract

The invention relates to biodegradable polyester films with a thickness of 8 to 40 µm and an oxygen permeability measured according to ASTM D3985-05:2010 of 1300 to 5500 ml/m²/day.

Description

Biodegradable film for food packaging

The invention relates to biodegradable, 8 to 40 μηη thick polyester films having an oxygen permeability measured according to ASTM D3985-05: 2010 of 1300 to 5500 ml / m ² / day.

In particular, the invention relates to biodegradable, 20 to 40 μηη thick polyester films having an oxygen permeability measured according to ASTM D3985-05: 2010 of 1300 to 4000 ml / m ² / day.

A preferred embodiment relates to biodegradable, 8 to 25 μηη thick polyester films having an oxygen permeability measured according to ASTM D3985-05: 2010 of 4000 to 5500 ml / m ² / day. Furthermore, the invention relates to polyester films, in addition to the above-mentioned oxygen permeability, a water vapor permeability measured according to ASTM F1249: 2013 of 100 to 1000 g / m ² / day.

The shelf life of fresh fruits and vegetables depends very much on its storage and transport. In particular, the nature of its packaging has a significant influence on the durability. Most perishable foods are packaged in non-biodegradable plastic films such as polypropylene, polyethylene and polyvinyl chloride films. This has the disadvantage that already spoiled goods including the packaging must be burned, which alone is ecologically meaningful due to the high water content. Furthermore, the films currently available on the market can often not fully satisfy with regard to their high oxygen permeabilities and their usually too low water vapor permeability.

Too high oxygen permeabilities of the film lead to an oxygen deficiency within the packaging and thus to an anaerobic respiration of the packaged food. On the other hand, too low an oxygen permeability of the film leads to an oxygen oversupply within the packaging and thus to an accelerated maturation of the packaged food. Both phenomena described: anaerobic respiration and accelerated maturation reduce the shelf life of the packaged food.

Too high a water vapor permeability of the film leads to a too rapid loss of water and thus drying of the packaged food. On the other hand, too low a water vapor permeability of the film can lead to the condensation of water within the package, which can promote rot and mildew. Both described phenomena: dehydration and decay reduce the shelf life of the packaged food. Accordingly, the aim of the present invention was to provide optimized packaging of a biodegradable material for certain foods, such as apples, onions, grapes, tomatoes, oranges, plums and grapefruits on the one hand and baked goods in particular, and potatoes, peaches, pears, cabbage and celery in particular, which guarantees an extended shelf life for the respective food.

Accordingly, the aforementioned biodegradable, 8 to 40 μηη thick polyester films were found with an oxygen permeability measured according to ASTM D3985-05: 2010 of 1300 to 5500 ml / m ² / day.

Preferably, the aforementioned polyester films contain the following polyester mixture:

60 to 95 wt .-%, preferably 85 to 95 wt .-%, based on the total weight of components i to ii, of a biodegradable polyester based on aliphatic C4-Ci8 dicarboxylic acids and / or aromatic C6-C10 dicarboxylic acids and an aliphatic C 2 -C 6 -dihydroxy compound;

5 to 40 wt .-%, preferably 5 to 15 wt .-%, based on the total weight of components i to ii, polylactic acid;

0 to 30 wt .-%, preferably 5 to 25 and particularly preferably 5 to 15% by weight, based on the total weight of components i to v, of an organic filler selected from the group consisting of: native or plasticized starch , Natural fibers, and / or an inorganic filler selected from the group consisting of: chalk, calcium carbonate, kaolin, silicate, wollastonite, montmorillonite and talc; iv) 0 to 1% by weight, preferably 0.05 to 0.2% by weight, based on the total weight of components i to v, of an epoxy group-containing copolymer based on

Styrene, acrylic acid ester and / or methacrylic acid ester. v) 0 to 1 wt .-%, based on the total weight of components i to v, of a wax such as beeswax or a Ci8-C24-carboxylic acid amides such as in particular stearic acid amide, erucic acid amide or behenamide.

In principle, all polyesters based on aliphatic C 4 -C 18 -dicarboxylic acids and an aliphatic C 2 -C 6 -dihydroxy compound (aliphatic polyesters) and based on aliphatic C 4 -C 18 -dicarboxylic acids and aromatic C 6 - are used as component i for the preparation of the biodegradable polyester mixtures according to the invention. C10

Dicarboxylic acids and an aliphatic C2-C6 dihydroxy compound (partially aromatic polyester) into consideration. Common to these polyesters is that they are biodegradable according to DIN EN 13432 are. Of course, mixtures of several such polyesters are suitable as component i.

Partly aromatic polyesters (component i) are also to be understood as meaning polyester derivatives according to the invention, such as polyether esters, polyester amides or polyetheresteramides, and polyesterurethanes. Suitable partially aromatic polyesters include linear non-chain extended polyesters (WO 92/09654). Preferred are chain-extended and / or branched partially aromatic polyesters. The latter are known from the documents cited at the outset, WO 96/15173 to 15176, 21689 to 21692, 25446, 25448 or WO 98/12242, to which reference is expressly made. Mixtures of different partially aromatic polyesters are also possible. Interesting recent developments are based on renewable raw materials (see WO-A 2006/097353, WO-A 2006/097354 and WO-A 2010/034710). In particular, under partly aromatic polyesters products such as Ecoflex ^® (BASF SE) and Origo ^"Bi ^® (Novamont) to understand.

Particularly preferred partially aromatic polyesters include polyesters as essential components

A) an acid component of a1) 30 to 99 mol%, preferably 40 to 60 mol% of at least one aliphatic C ₄ - cis-dicarboxylic acids or their ester-forming derivatives or mixtures thereof a2) 1 to 70 mol%, preferably 40 to 60 mol% of at least one aromatic C ₄ - cis-dicarboxylic acids or their ester-forming derivative or mixtures thereof and a diol component selected from at least one C _{2 to} C ₆ alkanediol or mixtures thereof and

C) a component selected from c1) a compound having at least three ester-capable groups, a di- or polyisocyanate, c3) a di- or polyepoxide or mixtures of c1) to c3). As aliphatic acids and the corresponding derivatives a1 are generally those having 4 to 18 carbon atoms, preferably 4 to 10 carbon atoms, into consideration. They can be both linear and branched. In principle, however, it is also possible to use dicarboxylic acids having a larger number of carbon atoms, for example up to 30 carbon atoms.

Examples which may be mentioned are: succinic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, α-ketoglutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, brassylic acid, fumaric acid, 2,2-dimethylglutaric acid, suberic acid (suberic acid), diglycolic acid, oxaloacetic acid, glutamic acid, Aspartic acid, itaconic acid and maleic acid. The dicarboxylic acids or their ester-forming derivatives may be used singly or as a mixture of two or more thereof.

Succinic acid, adipic acid, azelaic acid and sebacic acid, or their respective ester-forming derivatives or mixtures thereof are preferably used. Succinic acid, adipic acid or sebacic acid or their respective ester-forming derivatives or mixtures thereof are particularly preferably used. Succinic acid, azelaic acid and sebacic acid also have the advantage that they are accessible from renewable raw materials. Particular preference is given to the following aliphatic-aromatic polyesters: polybutylene acetate terephthalate (PBAT), polybutylene sebacate terephthalate (PBSeT) or polybutylene succinate terephthalate (PBST).

The aromatic C 6 -C 10 -dicarboxylic acids or their ester-forming derivatives a 2 can be used individually or as a mixture of two or more thereof. Terephthalic acid, isophthalic acid and 2,5-furandicarboxylic acid or their ester-forming derivatives are preferred, and terephthalic acid or its ester-forming derivatives, such as dimethylterephthalate, is particularly preferably used. In general, the diols B are selected from branched or linear alkanediols having 2 to 6 carbon atoms, preferably 3 to 6 carbon atoms.

Examples of suitable alkanediols are ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 4-butanediol, 1, 5-pentanediol and preferably ethylene glycol, 1, 3-propanediol, 1, 4-butanediol and 2,2-dimethyl-1,3-propanediol (neopentyl glycol). Particularly preferred are 1, 4-butanediol and 1, 3-propanediol. 1, 4-butanediol and 1, 3-propanediol also have the advantage that it is available as a renewable raw material. It is also possible to use mixtures of different alkanediols. The preferred partially aromatic polyesters are characterized by a molecular weight (M _n ) in the range from 1000 to 100 000, in particular in the range from 9000 to 75000 g / mol, preferably In the range of 10,000 to 50,000 g / mol and a melting point in the range of 60 to 170, preferably in the range of 80 to 150 ° C.

Aliphatic polyesters (component i) are understood as meaning polyesters of aliphatic diols and aliphatic dicarboxylic acids such as polybutylene succinate (PBS), polybutylene adipate (PBA), polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe), polybutylene sebacate (PBSe) or corresponding polyesteramides or polyester urethanes. The aliphatic polyesters are marketed, for example, by the companies Showa Highpolymers under the name Bionolle and by Mitsubishi under the name GSPIa.

The polyesters in component i may also contain mixtures of partly aromatic polyesters and purely aliphatic polyesters, for example mixtures of PBAT and PBS.

As component ii polylactic acid (PLA) is used.

Polylactic acid having the following property profile is preferably used:

A melt volume rate (MVR at 190 ° C. and 2.16 kg according to ISO 1 133 of 0.5, preferably 2 to 30, in particular 9 ml / 10 minutes

• a melting point below 240 ° C;

· A glass point (Tg) greater than 55 ° C

• a water content of less than 1000 ppm

• a residual monomer content (lactide) of less than 0.3%.

• a molecular weight greater than 80,000 daltons. Preferred polylactic acids are, for example, Ingeo® 6201 D, 6202 D, 6251 D, 3051 D and in particular Ingeo® 4020D, 4043D and 4044D (polylactic acid from NatureWorks) or Luminy® LX175 from Total Corbion.

As component iii) are usually 0 to 30 wt .-%, preferably 5 to 25 and particularly preferably 5 to 15 wt .-%, based on the total weight of components i to v, of an organic filler selected from the group consisting of: native or plasticized starch, natural fibers, and / or an inorganic filler selected from the group consisting of: calcium carbonate, talc, graphite, gypsum, carbon black, iron oxide, calcium chloride, kaolin, silica, sodium carbonate, titanium dioxide, silicate, wollastonite , Mica, montmorellonite used.

Calcium carbonate can be used, for example, in 5 to 20 wt .-%, preferably 5 to 15 wt .-%, and particularly preferably 5 to 10 wt .-%, based on the total weight of the polymer mixture. Among other things, the calcium carbonate from the company Omya has been suitable proved. The calcium carbonate generally has an average particle size of 0.5 to 10 micrometers, preferably 1 to 5, more preferably 1 to 2.5 micrometers.

Talc may for example be used in 1 to 10 wt .-%, particularly preferably 5 to 8 wt .-%, based on the total weight of the polymer mixture. Among other things, the talc from Mondo Minerals has proved suitable. The talc usually has an average particle size of 0.5-10, preferably 1-8, more preferably 1-3 microns.

In addition to the inorganic fillers calcium carbonate and talc may also contain other minerals such as: graphite, gypsum, carbon black, iron oxide, calcium chloride, kaolin, silica, sodium carbonate, titanium dioxide, silicate, wollastonite, mica, montmorellonite, mineral fibers and natural fibers.

Natural fibers are usually cellulose fibers, kenaf fibers, hemp fibers or wood flour. They are preferably used in 1 to 20 wt .-% based on the polymer mixture.

The minerals including the fillers calcium carbonate and talc can also be used as nanofillers. Nanofillers are in particular finely divided phyllosilicates, preferably clay minerals, particularly preferably montmorillonite containing clay minerals whose surface is modified with one or more quaternary ammonium salts and / or phosphonium salts and / or sulfonium salts. Preferred clay minerals are natural montmorillonites and bentonites.

Component iv is understood as meaning an epoxide-group-containing copolymer based on styrene, acrylic acid ester and / or methacrylic acid ester. The epoxy groups bearing units are preferably glycidyl (meth) acrylates. Copolymers having a glycidyl methacrylate content of greater than 20, particularly preferably greater than 30 and especially preferably greater than 50% by weight, of the copolymer have proved to be advantageous. The epoxy equivalent weight (EEW) in these polymers is preferably 150 to 3000, and more preferably 200 to 500 g / equivalent. The weight average molecular weight Mw of the polymers is preferably from 2,000 to 25,000, in particular from 3,000 to 8,000. The number-average molecular weight M _{n of} the polymers is preferably from 400 to 6,000, in particular from 1,000 to 4,000. The polydispersity (Q) is generally between 1 .5 and 5 epoxide groups-containing copolymers of the above type are sold for example by BASF Resins BV under the trademark Joncryl ^® ADR. Particularly suitable as a chain is Joncryl ^® ADR 4368 and ADR 4468th

Wax is usually used as component v. By wax is meant, for example, C18-C24 carboxylic acid amides such as stearic acid amide or preferably erucic acid amide or behenamide, or beeswax or beeswax esters. By adding waxes in 0.1 to 1 wt .-%, based on the components i to v, the water vapor permeability of the polyester film measured according to ASTM F1249: 2013 to the desired values of 100 to 300 g / m ² / day. An increase in the layer thickness of the polyester film also leads to a reduction in its water vapor permeability.

Furthermore, the polyester film according to the invention may contain further additives known to the person skilled in the art. For example, the usual additives in plastics technology such as stabilizers; nucleating agents; Lubricants and release agents such as stearates (especially calcium stearate); Plasticizers such as citric acid esters (especially acetyl tributyl citrate), glyceric acid esters such as triacetylglycerol or ethylene glycol derivatives, surfactants such as polysorbates, palmitates or laurates; Antistatic, UV absorber; UV-stabilizer; Antifog agents or dyes. The additives are generally used in concentrations of 0 to 2 wt .-%, in particular 0.1 to 1 wt .-% based on the polyester film according to the invention. Plasticizers may be contained in 0.1 to 10 wt .-% in the polyester film according to the invention. The 8 to 40 μηη thick polyester films according to the invention with an oxygen permeability measured according to ASTM D3985-05: 2010 of 1300 to 5500 ml / m ² / day are particularly suitable for the packaging of fruits and vegetables, the fruit and vegetables at 5 ° C a Carbon dioxide emissions of greater than 2 ml CO .- / kg h and a water output of over 40 mg / kg / sec / Mpa.

A higher layer thickness of the polyester film greatly reduces its oxygen permeability, so that the polyester films can be tailored by their chemical composition and the layer thickness for the respective packaged food almost to ensure optimum shelf life of the packaged food.

Thus, in particular biodegradable, 20 to 40 μηη thick polyester films of the above composition with an oxygen permeability measured according to ASTM D3985-05: 2010 from 1300 to 4000 ml / m ² / day produce. The polyester i used is preferably polybutylene adipate-co-terephthalate or a mixture of polybutylene adipate-co-terephthalate and polybutylene sebacate-co-terephthalate in a weight ratio of 20: 1 to 1: 1.

In order to be able to set mechanical properties (for example for flow packs) and barriers which are relevant to this invention and at the same time make the film sealable, multilayer structures consisting of stiff, higher barrier layers and soft / flexible are particularly suitable Layers that have a low barrier. Typically, three-layer structures are selected: The rigid layer a) consists of the components i) 40-10% by weight, based on the total weight of components i) and ii), of a polybutylene adipate-co-terephthalate or polybutylene-sebacate-co terephthalate or a mixture of the two polyesters and ii) 60-90% by weight, based on the total weight of components i) and ii), polylactic acid. The soft / flexible layer b) consists of the components i) 100-80% by weight, based on the total weight of components i) and ii), of a polybutylene adipate-co-terephthalate or polybutylene sebacate-co-terephthalate or a mixture the two polyesters and ii) 0-20 wt .-%, based on the total weight of components i) and ii), polylactic acid. The middle layer c) between outer layers a) and b) consists of components i) 100-10% by weight, based on the total weight of components i) and ii), of a polybutylene adipate-co-terephthalate or polybutylene sebacate-co-terephthalate or a mixture of the two polyesters and ii) 0-90 wt .-%, based on the total weight of components i) and ii), polylactic acid. Preference is given to a composition of components i) 70-50% by weight, based on the total weight of components i) and ii), of a polybutylene adipate-co-terephthalate or polybutylene sebacate-co-terephthalate or a mixture of the two polyesters and ii) 30 -50 wt .-%, based on the total weight of components i) and ii), polylactic acid.

Each of the layers also contains the components iii), iv) and v).

iii) 0 to 3% by weight of an inorganic filler selected from the group consisting of: chalk, calcium carbonate, kaolin, silicate, wollastonite, montmorillonite and talc; iv) 0 to 1 wt .-%, preferably 0.05 to 0.2 wt .-%, based on the total weight of components i to v, of an epoxy group-containing copolymer based on styrene, acrylic acid ester and / or methacrylic acid ester. v) 0 to 1 wt .-%, based on the total weight of components i to v, of a wax such as beeswax or a Ci8-C24-carboxylic acid amides such as in particular

Stearic acid amide, erucic acid amide or behenamide.

A typical 3-layer film is a total of 20- 40 μηη strong. Each layer occupies 1/3 of the total film thickness. However, it is also possible to build up with layers of different thicknesses - for example, a thinner middle layer.

The following structure (Example 1) of a 30 μηη thick 3-layer film with three equally strong layers a), b) and c) has proven particularly favorable: The rigid layer a) consists of the components i) 29.544% by weight, based on the Total weight of components i) to v), of a polybutylene adipate-co-terephthalate (ecoflex® F blend C1200); ii) 70.4% by weight, based on the total weight of components i) to v), of polylactic acid; iv) 0.05% by weight, based on the total weight of components i to v, of Joncryl ADR 4368 and v) of 0.006% by weight, based on the total weight of components i to v, of erucic acid amide.

The soft / flexible sealing layer b) consists of the components i) 88.4% by weight, based on the total weight of components i) to v), of a polybutylene adipate-co-terephthalate (ecoflex® F blend C1200); ii) 9% by weight, based on the total weight of components i) to v), of polylactic acid; iii) 2.4% by weight, calcium carbonate; iv) 0.1 wt .-%, based on the total weight of components i to v, Joncryl ADR4368 and v) 0.1 wt .-%, based on the total weight of components i to v, erucic acid amide.

The middle layer c) between the outer layers a) and b) consists of the components i) 67.7% by weight, based on the total weight of the components i) to v), of a polybutyleneadipate-co-terephthalate (ecoflex® F blend C1200); ii) 32 wt .-% based on the total weight of components i) to v), polylactic iv) 0.3 wt .-%, based on the total weight of components i to v, Joncryl ADR4368 and v) 0.03 wt. %, based on the total weight of components i to v, of erucic acid amide.

This composition corresponds in total to a composition of components i) 62.5% by weight, based on the total weight of components i) and ii), of a polybutylene adipate co-terephthalate (ecoflex® F blend C1200); ii) 37.5% by weight, based on the total weight of components i) and ii), polylactic acid; iii) 0.8% by weight, based on components i to v, calcium carbonate, iv) 0.133% by weight, based on the total weight of components i to v, Joncryl ADR4368 and v) 0.045% by weight on the total weight of components i to v, erucic acid amide. Example 1 with a layer thickness of 30 μm, with an oxygen permeability measured according to ASTM D3985-05: 2010 of 1410 ml / m ² / day and a water vapor permeability measured according to ASTM F1249: 2013 of 175 g / m ² / Day lead. Such films are excellent for the packaging of apples, onions, grapes, tomatoes, oranges, plums and grapefruit and thus contribute to an extension of the shelf life of these foods crucial.

As previously mentioned, the addition of wax can reduce the moisture vapor transmission rate of the polyester film as measured by ASTM F1249: 2013 to values less than 100 g / m ² / day. An increase in the layer thickness of the polyester film also leads to a reduction in its water vapor permeability. This is particularly interesting for the packaging of apples, onions and grapefruit, while for the packaging of grapes, tomatoes, oranges and plums, a water vapor permeability of about 100 to 300 g / m ² / day is beneficial, so that for packaging the latter food on the Addition of waxes can be largely or completely dispensed with.

Advantageously, therefore, the use of biodegradable, 20 to 40 μηη thick polyester films with an oxygen permeability measured according to ASTM D3985-05: 2010 of 1300 to 4000 ml / m ² / day for packaging of apples, onions, grapes, tomatoes, oranges, plums and grapefruit, as the packaging guarantees longer shelf life for these foods. In addition, it has proved to be advantageous in the polyester films for this purpose by the addition of small amounts of a wax (up to 1 wt .-% based on the composition of the polyester film) measured by a water vapor permeability ASTM F1249: 2013 from 100 to 300 g / m ² / day.

Particularly suitable for this purpose, for example, the 30 μηι 3-layer film of Example 1 or generally 20 to 40 μηη thick films of the following composition proved: i) 60 to 95 wt .-%, preferably 85 to 95 wt .-%, based on the total weight of components i to ii, of a biodegradable polyester based on aliphatic C4-C8 dicarboxylic acids and / or aromatic C6-C10 dicarboxylic acids and a C2-C6 aliphatic dihydroxy compound; ii) from 5 to 40% by weight, preferably from 5 to 15% by weight, based on the total weight of components i to ii, of polylactic acid; iii) 0 to 30% by weight, preferably 5 to 25 and particularly preferably 5 to 15% by weight, based on the total weight of components i to v, of an organic filler selected from the group consisting of: native or plasticized starch, natural fibers, and / or an inorganic filler selected from the group consisting of: chalk, calcium carbonate, kaolin, silicate, wollastonite, montmorillonite and talc; iv) 0 to 1 wt .-%, preferably 0.05 to 0.2 wt .-%, based on the total weight of components i to v, of an epoxy group-containing copolymer based on styrene, acrylic acid ester and / or methacrylic acid ester. v) 0 to 1 wt .-%, based on the total weight of components i to v, of a wax such as beeswax or a Ci8-C24-carboxylic acid amides such as in particular stearic acid amide, erucic acid amide or behenamide.

A preferred embodiment relates to biodegradable, 8 to 25 μηη, preferably 8 to 15 μηη thick polyester films having an oxygen permeability measured according to ASTM D3985-05: 2010 of 4000 to 5500 ml / m ² / day.

Preferably, the aforementioned polyester films consist of: i) from 85 to 95% by weight, preferably from 90 to 95% by weight, based on the total weight of components i to ii, of a polybutylene sebacate-co-terephthalate or a mixture of polybutylene sebacate-co-terephthalate terephthalate and polybutylene adipate cerephthalate in a weight ratio of 20: 1 to 1: 1 is used; ii) from 5 to 15% by weight, preferably from 5 to 10% by weight, based on the total weight of components i to ii, of polylactic acid;

5 to 13 wt .-%, preferably 6 to 10 wt .-%, based on the total weight of components i to v, calcium carbonate;

0 to 1 wt .-%, preferably 0.05 to 0.2 wt .-%, based on the total weight of components i to v, of an epoxy group-containing copolymer based on styrene, acrylic acid ester and / or methacrylic acid ester;

0 to 1 wt .-%, based on the total weight of components i to v, of a wax, preferably beeswax or a C18-C24 carboxylic acid amide such as stearic acid amide or particularly preferably erucic acid amide or behenamide. The aforementioned films, as shown in Examples 4 and 5 show - despite their thin layer thickness of only 14 μηη - compared to Examples 2 and 3 with the same layer thickness, improved tear strength (Elmendorf test), a slightly improved transparency according to ASTM D1003: 2013 and a significantly higher oxygen permeability measured according to ASTM D3985-05: 2010 of more than 4000 ml / m ² / day (see Table 2). They are therefore ideal for the packaging of baked goods and in particular of potatoes, peaches, pears, cabbage and celery, thus contributing to an extension of the shelf life of these foods. The use of these 8 to 25 μηη and preferably 8 to 15 μηη thick polyester films having the aforementioned composition for packaging baked goods and especially of potatoes, peaches, pears, cabbage and celery is thus also preferred.

Furthermore, the use of these 8 to 25 μηη and preferably 8 to 15 μηη thick polyester films with the aforementioned composition for the production of plastic bags for weighing fruits and vegetables in the supermarket is preferred. Here, the high tear strength and the comparatively high transparency of the thin films prove to be a decisive advantage.

Table 1

Example 2 Example 3 Example 4 Example 5

Composition [% by weight]

-1 86.75 82.25

-2 84.5 80 i-1 8 8 8 8

ii-1 5 9.5 5 9.5 v-1 0.05 0.05 0.05 0.05 v-1 0.2 0.2 0.2 0.2 i-1: ecoflex® F blend C1200 (polybutylene adipate coterephthalate from BASF SE) i-2: ecoflex® FS blend C1300 (polybutylene sebacate coterephthalate from BASF SE) i-1: Ingeo® 4044D (polylactic acid from the company. NatureWorks)

iii- 1: Omyafilm 764-OM (calcium carbonate from Omya)

iv-1: Joncryl® ADR 4368 (styrene containing epoxide group-containing copolymer,

(Meth) acrylate

v-1: erucic acid amide

Table 2

The oxygen permeability of the polyester film in the application always refers to the measurement method ASTM D3985-05: 2010 measured at 23 ° C. and dried oxygen. The water vapor permeability of the polyester film in the application always refers to the measuring method ASTM F1249: 2013 measured at 23 ° C and 100% RH.

The tear propagation resistance was determined by an Elmendorf test according to EN ISO 6383-2: 2004 with a device from Protear on test specimens with a constant radius (43 mm crack length).

The modulus of elasticity and the results of the tensile test were determined on foils produced by blown film with a thickness of about 14 μm in accordance with ISO 527-3: 2003-07. Total transmission, haze and clarity were measured according to ASTM D1003: 2013.

As previously mentioned, the addition of wax can reduce the moisture vapor transmission rate of the polyester film as measured by ASTM F1249: 2013 to levels below 100 g / m ² / day. An increase in the layer thickness of the polyester film also leads to a reduction in its water vapor permeability. This is particularly interesting for the packaging of potatoes. fine and pears. For the packing of cabbage, peaches and celery a water vapor permeability of more than 300 g / m ² / day is an advantage, so that the packaging of these foods can be dispensed with the addition of waxes. For the purposes of the present invention, the feature "biodegradable" for a substance or a substance mixture is fulfilled if this substance or the substance mixture according to DIN EN 13432 has a percentage degree of biodegradation of at least 90%.

In general, biodegradability causes the polyester (mixtures) to decompose in a reasonable and detectable time. Degradation can be effected enzymatically, hydrolytically, oxidatively and / or by the action of electromagnetic radiation, for example UV radiation, and is usually effected for the most part by the action of microorganisms such as bacteria, yeasts, fungi and algae. The biodegradability can be quantified, for example, by mixing polyesters with compost and storing them for a certain period of time. For example, according to DIN EN 13432 (referring to ISO 14855), C02-free air is allowed to flow through matured compost during composting and subjected to a defined temperature program. Here, the biodegradability is determined by the ratio of the net CO 2 release of the sample (after deduction of CO 2 release by the compost without sample) to the maximum CO 2 release of the sample (calculated from the carbon content of the sample) as a percentage of biodegradation Are defined. Biodegradable polyesters (mixtures) usually show clear degradation phenomena such as fungal growth, cracking and hole formation after only a few days of composting. Other methods of determining biodegradability are described, for example, in ASTM D 5338 and ASTM D 6400-4.

The abovementioned biodegradable polyester films are suitable for the production of nets and fabrics, tubular films, chill-roll films with and without orientation in a further process step, with and without metallization or SiOx coating.

In particular, the polyester films according to the invention comprising the components i) to v) are suitable for tubular films and stretch films. Possible applications are here Bodenfaltbeutel, side seam bags, carry bags with handle hole, shrink labels or shirt carrier bags, inliners, heavy bags, freezer bags, composting bags, film bags, peelable sealing film - transparent or opaque - weldable sealing film - transparent or opaque -, cling film (stretch film), peelable lidding films.

Claims

claims

1 . Biodegradable, 8 to 40 μηι thick polyester film with an oxygen permeability measured according to ASTM D3985-05: 2010 of 1300 to 5500 ml / m ² / day.

2. Biodegradable, 20 to 40 μηη thick polyester film with an oxygen permeability measured according to ASTM D3985-05: 2010 of 1300 to 4000 ml / m ² / day.

3. Biodegradable, 8 to 25 μηη thick polyester film with an oxygen permeability measured according to ASTM D3985-05: 2010 from 4000 to 5500 ml / m ² / day.

4. A polyester film according to any one of claims 1 to 3 having a water vapor permeability measured according to ASTM F1249: 2013 of 100 to 1000 g / m ² / day.

5. A polyester film according to any one of claims 1 to 4, comprising a polyester mixture of: i) 85 to 95 wt .-%, based on the total weight of components i to ii, of a biodegradable polyester based on aliphatic C4-C18 dicarboxylic acids and or aromatic C6-Cio-dicarboxylic acids and an aliphatic C2-C6-dihydroxy compound; ii) from 5 to 15% by weight, based on the total weight of components i to ii, of polylactic acid; iii) from 5 to 30% by weight, based on the total weight of components i toiv, of an organic filler selected from the group consisting of: native or plasticized starch, natural fibers, and / or an inorganic filler selected from the group consisting of of: calcium carbonate, talc, graphite, gypsum, carbon black, iron oxide, calcium chloride, kaolin, silica, sodium carbonate, titanium dioxide, silicate, wollastonite, mica, montmorellonite; iv) 0 to 1% by weight, preferably 0.05 to 0.2% by weight, based on the total weight of components i to v, of an epoxide group-containing copolymer based on styrene, acrylate and / or methacrylic acid ester; v) 0 to 1 wt .-%, based on the total weight of components i to v, of a wax.

6. A polyester film according to claim 5, wherein in polyester i) as aliphatic C4-C18 dicarboxylic acid: succinic acid, adipic acid, sebacic acid or azelaic acid; as aromatic C6-Cio-dicarboxylic acid: terephthalic acid, isophthalic acid, 2,5 furandicarboxylic acid and as C2-C6-dihydroxy compound: 1, 4-butanediol or 1, 3-propanediol is used.

7. Biodegradable, 20 to 40 μηι thick polyester film having an oxygen permeability measured according to ASTM D3985-05: 2010 of 1300 to 4000 ml / m ² / day according to claim 5, wherein as polyester i): Polybutylenadipat-co-terephthalate or a mixture from polybutylene adipate-co-terephthalate and polybutylene sebacate-co-terephthalate in a weight ratio of 20: 1 to 1: 1 is used.

8. Biodegradable, 8 to 25 μηη thick polyester film according to claim 3 and / or 4 containing a polyester mixture of: i) 85 to 95 wt .-%, preferably 90 to 95 wt .-%, based on the total weight of components i to ii, a polybutylene sebacate-co-terephthalate or a mixture of polybutylene sebacate-co-terephthalate and polybutylene adipate-co-terephthalate in a weight ratio of 20: 1 to 1: 1; ii) from 5 to 15% by weight, preferably from 5 to 10% by weight, based on the total weight of components i to ii, of polylactic acid; iii) from 5 to 13% by weight, preferably from 6 to 10% by weight, based on the total weight of components i to v, of calcium carbonate; iv) 0 to 1% by weight, preferably 0.05 to 0.2% by weight, based on the total weight of components i to v, of an epoxide group-containing copolymer based on styrene, acrylate and / or methacrylic acid ester; v) 0 to 1 wt .-%, based on the total weight of components i to v, one

Wax.

9. Biodegradable, 8 to 15 μηη thick polyester film according to claim 8 with a Haze (image sharpness) measured according to ASTM D1003: 2013 of over 30%.

10. Use of a film according to claim 1 to 9 for the packaging of fruits and vegetables, wherein the fruits and vegetables at 5 C, a carbon dioxide emission of greater than 2 ml

CO .- / kg h and a water output of over 40 mg / kg / sec / Mpa.

1 1. Use of a film according to claims 2 and 7 for the packaging of apples, onions, grapes, tomatoes, oranges, plums and grapefruit.

12. Use of a film according to claim 3, 8 and 9 for the packaging of potatoes, pears, peach, cabbage and celery.

13. Use of a film according to any one of claims 8 or 9 for the production of plastic bags for weighing fruit and vegetables in the supermarket.