BIODEGRADABLE FILM

Description

[0001] The invention relates to a film and a method for its production. Furthermore, the invention relates to the use of a polymer blend for the production of a film. The invention also relates to transport bags.

[0002] The pollution of the world's oceans with plastic waste is a problem that has been known for decades and remains unresolved. Plastic poses a major threat, especially to marine animals. These animals become entangled in larger pieces of plastic and mistake smaller pieces for food, which they cannot digest. Particularly small plastic particles, known as microplastics, are ingested by animals and thus enter the human food chain.

[0003] A large proportion of the plastic debris found in the world's oceans originates from plastic carrier bags ("plastic bags"), such as those used daily for shopping. The terms "plastic" and "plastic" are used synonymously in the following text.

[0004] Recycling, the sustainable use of plastic products, and cleaning up the world's oceans are approaches intended to contribute to reducing the amount of plastic in the world's oceans. However, the safest and most sustainable solution would be to be able to produce plastic products that biodegrade under the natural conditions found in the world's oceans.

[0005] The biodegradation of plastic products in natural seawater (saltwater) is significantly more protracted and problematic than biodegradation in active media such as compost or at the higher temperatures found in industrial composting facilities. Firstly, compost has a particularly high concentration of degradation microorganisms. Secondly, industrial composting facilities have precisely controlled conditions (e.g., temperature, oxygen concentration) that ensure optimal biodegradation of the compost. The requirements for plastic products that are biodegradable in the natural conditions of the world's oceans are therefore considerably higher than for other degradation environments.

[0006] Furthermore, in addition to good biodegradability under the natural conditions of the world's oceans, plastic products must also possess application-specific mechanical properties. For example, plastic transport bags must have sufficient tensile strength and elongation at break to be used as intended in everyday life. Only then can they be considered as a replacement for traditional, non-biodegradable plastic products.

[0007] Combining (a) good biodegradability of a plastic film in seawater on the one hand and (b) good mechanical properties of a plastic film on the other hand proves to be extremely difficult in practice. Previous approaches to reconciling these two seemingly contradictory properties of a film have only been partially successful.

[0008] EP 2 913 362 A1 describes a film comprising polyhydroxyalkanoates and polylactides, which exhibits improved biodegradability in an environment containing microorganisms while also possessing good storage stability, strength, and flexibility. However, the biodegradability is not optimized for the particularly demanding degradation conditions found in natural seawater.

[0009] EP 1 008 629 A1 describes a biodegradable polyester resin comprising 100 parts by weight of an aliphatic polyester resin and 1-200 parts by weight of polycaprolactone. A variety of different biodegradable products can be manufactured from this polymer mixture. However, its biodegradability is not adapted to the particularly demanding degradation conditions found in natural seawater.

[0010] None of the described films simultaneously solves the problem of the particular challenge of biodegradation in seawater and still exhibits satisfactory mechanical properties.

[0011] WO 2016 / 079244 describes a multilayer film comprising a middle layer whose polymeric components are soluble in aqueous solutions and a substantially water-impermeable top layer arranged above and below the middle layer, wherein the layers each contain at least one thermoplastic polymer independently of each other and at least one of the top layers contains at least one polyhydroxyalkanoate.

[0012] Based on the prior art described above, the object of the invention is to provide a film that exhibits very good biodegradability in seawater and simultaneously possesses excellent mechanical properties. Preferably, the film should decompose into smaller particles after being introduced into seawater—simultaneously with, before, or after the start of the biodegradation of the film (parts) to carbon dioxide and water. The invention also aims to provide a film that is particularly suitable for the production of transport bags.

[0013] These problems are solved wholly or partly by the foil specified in claim 1, the use specified in claim 8, the product specified in claim 10 and the method specified in claim 12.

[0014] Advantageous embodiments of the invention are specified in the dependent claims and are explained in detail below, as is the general concept of the invention.

[0015] The film according to the invention is characterized in that it contains 10 to 90 wt.% of component A and 10 to 90 wt.% of component B, based on the sum of components A and B, wherein component A is a polyhydroxyalkanoate and component B is an aliphatic copolyester composed of at least one diol component and at least one dicarboxylic acid component, wherein the film is formed as a single-layer film and wherein the film has a total thickness of 1 to 200 µm.

[0016] Surprisingly, it has been shown that the films according to the invention exhibit both excellent mechanical properties such as high tensile strength and / or high elongation at break and very good biodegradability in natural seawater.

[0017] Without wishing to be bound to a scientific theory, the surprising effect of the invention appears to be attributable to the special properties of the combination of components A and B. Extensive experimental studies were necessary to find suitable components and ratios for A and B. When polymers other than those defined for A and B were combined, the resulting films either exhibited insufficient mechanical properties or their biodegradability in seawater was inadequate. Furthermore, the correct ratio of A and B is essential for both the biodegradability in seawater and the mechanical properties of the films.

[0018] According to the invention, the film has at least one of the following mechanical properties: Tensile strength in dry condition in extrusion direction (MD) of at least 15 MPa according to EN ISO 527; tensile strength in dry condition transverse to extrusion direction (TD) of at least 15 MPa according to EN ISO 527; elongation at break in dry condition in extrusion direction (MD) of at least 100% according to EN ISO 527; elongation at break in dry condition transverse to extrusion direction (TD) of at least 100% according to EN ISO 527.

[0019] The aforementioned mechanical properties are preferably determined in accordance with EN ISO 527-3:2003-07.

[0020] According to the invention, after immersion in salt water for a period of 12 weeks under controlled test conditions, according to method ASTM D6691-09, the film, after sieving through a sieve with a mesh size of 2.0 mm, exhibits a maximum of 30 wt.% of the original dry weight and / or at least 30% of the organic carbon of the film is converted into carbon dioxide after immersion in salt water within 180 days at a temperature of 30 ± 2 °C, according to method ASTM D6691-09.

[0021] The measurement of degradation in salt water under controlled test conditions according to ASTM D6691-09 is preferably carried out on films with a thickness of 1 to 100 µm, in particular from 10 to 40 µm, more preferably with a thickness of about 20 µm.

[0022] In an exemplary embodiment, the film contains 10 to 90 wt% of component A and 10 to 90 wt% of component B, based on the sum of components A and B, wherein component A is a polyhydroxyalkanoate and component B is an aliphatic copolyester composed of at least one diol component and at least one dicarboxylic acid component, and wherein the film has a total thickness of 1 to 200 µm and at least one of the following mechanical properties: Tensile strength in dry condition in extrusion direction (MD) of at least 15 MPa according to EN ISO 527; tensile strength in dry condition transverse to extrusion direction (TD) of at least 15 MPa according to EN ISO 527; elongation at break in dry condition in extrusion direction (MD) of at least 100% according to EN ISO 527; elongation at break in dry condition transverse to extrusion direction (TD) of at least 100% according to EN ISO 527; and wherein, after immersion in salt water for a period of 12 weeks under controlled test conditions according to method ASTM D6691-09, the film, after sieving through a sieve with a mesh size of 2.0 mm, exhibits a maximum of 30 wt% of the original dry weight and / or wherein at least 30% of the organic carbon of the film, after immersion in salt water, is converted to carbon dioxide within 180 days at a temperature of 30 ± 2 °C according to method ASTM D6691-09.

[0023] The film according to the invention contains a component A, which is a polyhydroxyalkanoate.

[0024] When polyhydroxyalkanoates are mentioned here or elsewhere, this refers to polyesters of hydroxy fatty acids containing monomers with a chain length of at least 4 carbon atoms, in particular 4 to 18 carbon atoms or 4 to 9 carbon atoms. Polylactic acid, for example, is therefore not a polyhydroxyalkanoate within the meaning of the invention.

[0025] According to an advantageous embodiment of the invention, component A may be selected from the group consisting of poly(3-hydroxybutanoate), poly(3-hydroxyvalerate), poly(3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-3-valerate), poly(3-hydroxybutyrate-co-3-hexanoate) and mixtures thereof.

[0026] According to a further advantageous embodiment, component A can be selected from the group consisting of poly(3-hydroxybutyrate-co-3-valerate), poly(3-hydroxybutyrate-co-3-hexanoate), and mixtures thereof. In a particularly preferred embodiment of the invention, component A is poly(3-hydroxybutyrate-co-3-hexanoate).

[0027] In addition to component A, the film contains at least one further component B. According to the invention, component B is an aliphatic copolyester composed of at least one diol component and at least one dicarboxylic acid component. According to a preferred embodiment of the invention, component B is an aliphatic copolyester composed of at least one diol component and at least two dicarboxylic acid components.

[0028] According to the invention, the carbon skeleton of the diol component can be linear, chain-branched, and / or cyclic. The diol component according to the invention has a chain length of at least two and at most twelve carbon atoms. A chain length of two to six carbon atoms is preferred. Preferably, the diol component is selected from the group consisting of 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,3-hexanediol, 2,4-hexanediol, 2,5-hexanediol, 3,4-hexanediol, 1,2-cyclopentanediol. 1,3-Cyclopentanediol, 1,2-Cyclohexanediol, 1,3-Cyclohexanediol, 1,4-Cyclohexanediol, Diethylene glycol, Triethylene glycol and mixtures thereof.Particularly preferred as the diol component of component B according to the invention are diols selected from the group consisting of 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol and mixtures thereof. 1,4-Butanediol is most preferably selected as the diol component.

[0029] According to the invention, the carbon skeleton of the dicarboxylic acid component can be linear, branched, and / or cyclic; preferably, the carbon skeleton of the dicarboxylic acid component is linear. The dicarboxylic acid component according to the invention has a chain length of two to twenty carbon atoms, preferably four to twelve carbon atoms. Preferably, the dicarboxylic acid component is selected from the group consisting of succinic acid, adipic acid, sebacic acid, azelaic acid, 1,12-dodecanedioic acid, and mixtures thereof. Particularly preferably, the dicarboxylic acid component according to the invention is selected from the group consisting of succinic acid, adipic acid, sebacic acid, and mixtures thereof.

[0030] Preferably, the aliphatic copolyester according to component B is a thermoplastic aliphatic copolyester.

[0031] The diol and dicarboxylic acid components according to component B can be produced chemically and / or biologically.

[0032] In a preferred embodiment of the invention, the aliphatic copolyester according to component B is polybutylene succinate or polybutylene adipate co-succinate. A particularly preferred embodiment of the invention uses polybutylene adipate co-succinate as component B.

[0033] The film according to the invention can contain further polymeric components in addition to components A and B. In particular, the film according to the invention can contain, in addition to components A and B, poly(butylene adipate co-terephthalate) (PBAT) or poly(butylene sebacate co-terephthalate) (PBST) or mixtures thereof.

[0034] According to one embodiment, the film comprises 0.1 to 30 wt.%, preferably 1 to 25 wt.%, preferably 3 to 20 wt.%, further preferably 4 to 15 wt.%, and particularly preferably 5 to 12 wt.% of poly(butylene adipate co-terephthalate) and / or poly(butylene sebaceous co-terephthalate) (PBST). According to another embodiment, the film comprises 15 to 25 wt.%, preferably 17 to 23 wt.%, and particularly preferably 18 to 22 wt.% of poly(butylene adipate co-terephthalate) and / or poly(butylene sebaceous co-terephthalate) (PBST).

[0035] As a further component, the film according to the invention can contain 0.1 to 20 wt.%, preferably 2 to 18 wt.%, more preferably 5 to 15 wt.%, particularly preferably 8-12 wt.% starch.

[0036] According to the invention, the starch used can include, among other things, thermoplastic starch, denatured starch and / or starch derivatives. Thermoplastic starch is preferred.

[0037] For many applications, it is advantageous if the film has a total thickness of 5 to 200 µm, preferably 10 to 80 µm, and particularly preferably 15 to 60 µm. The film is suitable for manufacturing different products in various thicknesses. Films of the aforementioned thicknesses are particularly suitable for manufacturing carrier bags and transport bags for everyday use.

[0038] The mechanical properties and biodegradability of the film according to the invention are largely determined by the ratio of components A and B.

[0039] The film according to the invention contains 10 to 90 wt.% of component A based on the sum of components A and B. According to a preferred embodiment of the invention, the film preferably contains 20 to 80 wt.%, and particularly preferably 25 to 75 wt.% of component A based on the sum of components A and B.

[0040] The film according to the invention contains 10 to 90 wt.% of component B based on the sum of components A and B. In a preferred embodiment of the invention, the film preferably contains 20 to 80 wt.%, more preferably 25 to 75 wt.% of component B, based on the sum of components A and B.

[0041] According to a preferred embodiment of the invention, the film contains 10 to 50 wt.%, preferably 20 to 40 wt.%, more preferably 25 to 40 wt.%, still more preferably 25 to 35 wt.% and particularly preferably 28 to 32 wt.% of component A, based on the sum of components A and B. According to this embodiment, the film further preferably contains 50 to 90 wt.%, more preferably 60 to 80 wt.%, still more preferably 60 to 75 wt.%, still more preferably 65 to 75 wt.% and particularly preferably 68 to 72 wt.% of component B, based on the sum of components A and B.

[0042] According to a further preferred embodiment of the invention, the film contains 10 to 50 wt.%, preferably 20 to 40 wt.%, more preferably 25 to 40 wt.%, still more preferably 25 to 35 wt.% and particularly preferably 28 to 32 wt.% of component B, based on the sum of components A and B. According to this embodiment, the film further preferably contains 50 to 90 wt.%, more preferably 60 to 80 wt.%, still more preferably 60 to 75 wt.%, still more preferably 65 to 75 wt.% and particularly preferably 68 to 72 wt.% of component A, based on the sum of components A and B.

[0043] When component B is mentioned here or elsewhere, this component B may consist of one or more compounds. In a preferred embodiment of the invention, component B consists of a single compound. In another preferred embodiment of the invention, component B consists of several different compounds, in particular two or three different compounds.

[0044] The film according to the invention is characterized by excellent mechanical properties, which enable its use in transport bags.

[0045] The film according to the invention preferably exhibits an elongation at break in the extrusion direction (MD, machine direction) of at least 100% in its dry state, according to EN ISO 527. In a preferred embodiment of the invention, the elongation at break in the extrusion direction (MD), according to EN ISO 527, is at least 150%, preferably at least 200%, more preferably at least 300%, and particularly preferably at least 400%.

[0046] Furthermore, the film according to the invention preferably exhibits an elongation at break against the extrusion direction (TD, transverse direction) of at least 100% in the dry state, according to EN ISO 527. In a preferred embodiment of the invention, the elongation at break against the extrusion direction (TD), according to EN ISO 527, is at least 150%, preferably at least 200%, more preferably at least 300%, and particularly preferably at least 400%.

[0047] In addition, the film according to the invention preferably has a tensile strength in the extrusion direction (MD) of at least 15 MPa in the dry state, according to EN ISO 527. According to a preferred embodiment of the invention, the tensile strength in the extrusion direction (MD) of the film in the dry state is at least 20 MPa, preferably at least 25 MPa, and particularly preferably at least 30 MPa.

[0048] Furthermore, the film according to the invention preferably has a tensile strength against the extrusion direction (TD) of at least 15 MPa in the dry state, according to EN ISO 527. According to a preferred embodiment of the invention, the tensile strength against the extrusion direction (TD) of the film in the dry state is at least 20 MPa, preferably at least 25 MPa, and particularly preferably at least 30 MPa.

[0049] Advantageously, the film has a dart drop value in dry condition of at least 4 g / µm, preferably at least 5 g / µm, particularly preferably at least 6 g / µm, according to method ASTM D1709.

[0050] In addition to its excellent mechanical properties, the film according to the invention is also characterized by very good biodegradability and rapid decomposition in salt water.

[0051] Thus, the film according to the invention preferably exhibits, after immersion in salt water for a period of 12 weeks under controlled test conditions, according to method ASTM D6691-09, after sieving through a sieve with a mesh size of 2.0 mm, a maximum of 30 wt.% of the original dry weight.

[0052] In a preferred embodiment of the invention, after immersion in salt water for a period of 12 weeks under controlled test conditions according to method ASTM D6691-09, the film, after sieving through a sieve with a mesh size of 2.0 mm, has a maximum of 20 wt.%, preferably a maximum of 10 wt.% of the original dry weight.

[0053] The term saltwater here refers to a natural seawater medium according to point 7.5.2 of the ASTM D6691-09 method.

[0054] When ASTM D6691-09 is mentioned here or elsewhere, it refers to the version issued on November 15, 2009, entitled "Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials in the Marine Environment by a Defined Microbial Consortium or Natural Sea Water Inoculum". " meant.

[0055] The film according to the invention exhibits excellent biodegradability in salt water. Preferably, at least 30% of the organic carbon of the film according to the invention is converted to carbon dioxide within 180 days after immersion of the film in salt water at a temperature of 30 ± 2°C, according to method ASTM D6691-09.

[0056] In a preferred embodiment of the invention, after immersion of the film in salt water for 180 days at a temperature of 30 ± 2°C under controlled test conditions according to method ASTM D6691-09, preferably at least 40%, and particularly preferably at least 50%, of the organic carbon of the film is converted into carbon dioxide. The term "salt water" here refers to a natural seawater medium as defined in section 7.5.2 of method ASTM D6691-09.

[0057] The biodegradation of the film according to the invention is not only exceptionally effective under the natural conditions of seawater. In a preferred embodiment of the invention, the organic carbon of the film is converted to carbon dioxide within 180 days under active degradation conditions according to the method DIN EN ISO 14855-1:2012, preferably to at least 70%, more preferably to at least 80%, and particularly preferably to at least 90%.

[0058] The biodegradation of the film in seawater generally occurs in two steps, which may begin simultaneously or sequentially. First, the film according to the invention breaks down into smaller pieces in the seawater ("fragmentation"). Second, the plastic particles are biodegraded at the molecular level by being converted into carbon dioxide and water by microorganisms ("biodegradation"). Frequently, but not necessarily, the "fragmentation" step precedes the "biodegradation" step.

[0059] The film according to the invention is designed as a single-layer film, since a single-layer film is particularly easy and inexpensive to produce and can be further processed into transport bags.

[0060] The film according to the invention may contain additional components besides those mentioned.

[0061] The film according to the invention may also contain, for example, plasticizers. Examples of plasticizers include glycerin, sorbitol, arabinose, lycose, xylose, glucose, fructose, mannose, allose, altrose, galactose, gulose, iodose, inositol, sorbose, talitol and monoethoxylate, monopropoxylate and monoacetate derivatives thereof, as well as ethylene, ethylene glycol, propylene glycol, ethylene diglycol, propylene diglycol, ethylene triglycol, propylene triglycol, polyethylene glycol, polypropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-, 1,3-, 1,4-butanediol, 1,5-pentanediol, 1,6-,1,5-hexanediol, 1,2,6-, 1,3,5-hexanetriol, neopentyl glycol, trimethylopropane, pentaerythritol, sorbitol and their derivatives. Acetate, ethoxylate and propoxylate derivatives and mixtures thereof.

[0062] Preferably, the film according to the invention is free of oligomeric ester compounds with a weight-average molecular weight of 500 to 5000 g / mol, in particular of poly(1,3-butylene glycol-co-1,2-propylene glycol adipic acid) terminated with 2-ethylhexanol, poly(neopentyl glycol-co-1,4-butylene glycol adipic acid) terminated with 2-ethylhexanol, non-terminated poly(1,3-butylene glycol adipic acid), poly(1,2-propylene glycol adipic acid-co-phthalic acid) terminated with 2-ethylhexanol, poly(neopentyl glycol adipic acid) terminated with 2-ethylhexanol, poly(1,2-propylene glycol adipic acid-co-phthalic acid) terminated with 2-ethylhexanol, poly(1,3-butylene glycol adipic acid) terminated with mixed fatty acids, Poly(1,2-propylene glycol adipic acid) terminated with 2-ethylhexanol, poly(1,2-propylene glycol-co-1,4-butylene glycol adipic acid) terminated with 2-ethylhexanol, poly(1,4-butylene glycol adipic acid) or poly(1,4-butylene glycol-co-ethylene glycol adipic acid),each with a weight-average molecular weight of 500 to 5000 g / mol.,

[0063] Furthermore, the film according to the invention may contain dispersing aids such as detergents, melt stabilizers, processing aids, stabilizers, antioxidants, flame retardants, antiblocking agents, fillers and / or additives.

[0064] Furthermore, the film according to the invention can additionally contain other polymers such as polyethylene glycol, polyvinyl alcohol, chitin, chitosan, cellulose, cellulose derivatives, polyester, polydimethylaminoethyl methacrylate and mixtures thereof.

[0065] According to a further preferred embodiment of the invention, the film according to the invention contains one or more fillers and / or one or more disintegrants. Depending on the type and amount of filler and / or disintegrant, the disintegration rate of the film according to the invention can be influenced.

[0066] Preferred fillers for this purpose are selected from the group consisting of calcium carbonate, talc, kaolin, dolomite, mica, silica, and mixtures thereof. Disintegrants are known to those skilled in the art. Preferred disintegrants for this purpose are selected from the group consisting of sodium bicarbonate, alginic acid, calcium alginate, sodium alginate, microcrystalline cellulose, sodium carboxymethylcellulose, starch, sodium carboxymethyl starch, polyvinylpyrrolidone, and mixtures thereof. Starch may be in its native or destructured form.

[0067] The invention further relates to the use of a polymer blend containing 10-90 wt% of component A and 10-90 wt% of component B, based on the sum of components A and B, wherein component A is a polyhydroxyalkanoate and component B is an aliphatic copolyester composed of at least one diol component and at least one dicarboxylic acid component, for the production of a film, wherein the film is designed as a single-layer film with a total thickness of 1 to 200 µm and at least one of the following mechanical properties: Tensile strength in dry condition in extrusion direction (MD) of at least 15 MPa according to EN ISO 527; tensile strength in dry condition transverse to extrusion direction (TD) of at least 15 MPa according to EN ISO 527; elongation at break in dry condition in extrusion direction (MD) of at least 100% according to EN ISO 527; elongation at break in dry condition transverse to extrusion direction (TD) of at least 100% according to EN ISO 527; and wherein the film, after being immersed in salt water for a period of 12 weeks under controlled test conditions, according to method ASTM D6691-09, after sieving through a sieve with a mesh size of 2.0 mm, has a maximum of 30 wt.% of the original dry weight and / or wherein at least 30% of the organic carbon of the film is recovered after immersion in salt water within 180 days at a The substances were converted into carbon dioxide at a temperature of 30 ± 2 °C, according to the method ASTM D6691-09.

[0068] The statements made regarding components A and B of the film according to the invention apply accordingly to components A and B of the use according to the invention.

[0069] Preferably, the polymer blend contains 20 to 80 wt.% or 25 to 75 wt.% of component A, based on the sum of components A and B. Furthermore, the polymer blend preferably contains 20 to 80 wt.% or 25 to 75 wt.% of component B, based on the sum of components A and B.

[0070] According to a preferred embodiment of the invention, the polymer blend contains 10 to 50 wt.%, preferably 20 to 40 wt.%, more preferably 25 to 40 wt.%, even more preferably 25 to 35 wt.% and particularly preferably 28 to 32 wt.% of component A, based on the sum of components A and B. According to this embodiment, the polymer blend further preferably contains 50 to 90 wt.%, more preferably 60 to 80 wt.%, even more preferably 60 to 75 wt.%, even more preferably 65 to 75 wt.% and particularly preferably 68 to 72 wt.% of component B, based on the sum of components A and B.

[0071] According to a further preferred embodiment of the invention, the polymer blend contains 10 to 50 wt.%, preferably 20 to 40 wt.%, more preferably 25 to 40 wt.%, even more preferably 25 to 35 wt.% and particularly preferably 28 to 32 wt.% of component B, based on the sum of components A and B. According to this embodiment, the polymer blend further preferably contains 50 to 90 wt.%, more preferably 60 to 80 wt.%, even more preferably 60 to 75 wt.%, even more preferably 65 to 75 wt.% and particularly preferably 68 to 72 wt.% of component A, based on the sum of components A and B.

[0072] Furthermore, the polymer blend may contain one or more of the aforementioned components.

[0073] The invention also relates to products that are manufactured or can be manufactured with the film according to the invention.

[0074] Of particular importance are transport bags that are manufactured or can be manufactured from the film according to the invention. The films according to the invention are suitable for the production of transport bags of all kinds, including carrier bags, fruit bags, vegetable bags, light T-shirt bags and ultra-light T-shirt bags.

[0075] The different types of transport bags can have different weights depending on the intended use. In a preferred embodiment of the invention, for example, a transport bag according to the invention has a weight of preferably 1 to 90 g, more preferably 2 to 50 g, or particularly preferably 20 to 40 g. For other applications, transport bags according to the invention are particularly suitable which have a weight of preferably 1 to 10 g, and particularly preferably 1.5 to 5 g.

[0076] Finally, the invention also relates to a method for producing a film according to claim 12.

[0077] Suitable methods for forming a film according to step b. are generally known to those skilled in the art. For components A and B of the method according to the invention, what has been said about components A and B of the film according to the invention applies accordingly.

[0078] Preferably, the polymer blend contains 20 to 80 wt.% or 25 to 75 wt.% of component A, based on the sum of components A and B. Furthermore, the polymer blend preferably contains 20 to 80 wt.% or 25 to 75 wt.% of component B, based on the sum of components A and B. According to a preferred embodiment of the process according to the invention, the polymer blend contains 10 to 50 wt.%, preferably 20 to 40 wt.%, more preferably 25 to 40 wt.%, still more preferably 25 to 35 wt.%, and particularly preferably 28 to 32 wt.% of component A, based on the sum of components A and B. According to this embodiment, the polymer blend further preferably contains 50 to 90 wt.%, more preferably 60 to 80 wt.%, still more preferably 60 to 75 wt.%, still more preferably 65 to 75 wt.%, and particularly preferably 68 to 72 wt.% of component B, based on the sum of components A and B.

[0079] According to a further preferred embodiment of the process according to the invention, the polymer blend contains 10 to 50 wt.%, preferably 20 to 40 wt.%, more preferably 25 to 40 wt.%, even more preferably 25 to 35 wt.% and particularly preferably 28 to 32 wt.% of component B, based on the sum of components A and B. According to this embodiment, the polymer blend further preferably contains 50 to 90 wt.%, more preferably 60 to 80 wt.%, even more preferably 60 to 75 wt.%, even more preferably 65 to 75 wt.% and particularly preferably 68 to 72 wt.% of component A, based on the sum of components A and B.

[0080] Furthermore, the polymer blend may contain one or more of the aforementioned components.

[0081] The invention will be explained in more detail below using exemplary embodiments. Examples

[0082] The following materials were used for the comparison and implementation examples: Poly(butylene succinate co-adipate), PBSA (BioPBS FD92PM, PTT MCC Biochem Company Limited); Poly(hydroxybutyrate co-hexanoate), PHBH (AONILEX 151N; KANEKA); Erucic acid amide (LOXIOL E SPEZ P, Emery Oleochemicals). Example 1:

[0083] A polymer blend with the formulation A specified in Table 1 was produced and processed into granules using a Coperion ZSK 40 twin-screw extruder (twin-screw kneader), screw diameter 40 mm, L / D = 42 (dosed proportions in mass percent): Table 1: Recipe A Connection Crowd PHBH 29,7 PBSA 69,3 Loxiol 1

[0084] The following compounding parameters were adhered to: Table 2: Temperature profile (twin screw extruder ZSK 40) Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9 Zone 10 nozzle 25 °C 105 °C 120 °C 120 °C 135 °C 155 °C 165 °C 165 °C 165 °C 160 °C 160 °C speed 100 min -1< throughput 50 kg / h Degassing - 0.98 bar, Zone 8 Water content 0,1 %

[0085] Blown films were produced from the manufactured granules. For this purpose, the granules A were melted using a single-screw extruder of type KABRA, screw diameter 65 mm, L / D = 23, and processed into a blown film.

[0086] To investigate the film's durability in water, samples were mounted in slide frames and immersed in natural seawater. The film's decomposition was visually assessed. Table 3 documents the relative decomposition of the film within a period of 72 days in seawater. Table 3: Relative decomposition of the film obtainable from granules A days decomposition 0 1 22 1 37 (3) -4 72 4 Legend:

[0087] Value Meaning 1 Foil intact 2 Decomposition visible 3 advanced decomposition 4 The foil is completely decomposed.

[0088] Additionally, the mechanical properties of the film were checked. Tensile strength and elongation at break were measured on a Tinius Olsen H10KS universal testing machine.

[0089] The DM 2000 precision thickness gauge from Wolf-Messtechnik was used to determine the film thickness. The measurement results are listed in Table 4. Table 4: Mechanical properties of the film Film thickness [µm] Tensile strength (MD) [MPa] Tensile strength (TD) [MPa] Elongation at break (MD) [%] Elongation at Break (TD) [%] 25-30 39,1 35,5 665 816

[0090] As can be seen in Tables 3 and 4, the film exhibits excellent mechanical properties for use as a transport bag and very good decomposition in seawater. After just over a month in seawater, the film had almost completely decomposed (Table 3, line 3). Example 2:

[0091] A polymer blend with the formulation B specified in Table 5 was produced and processed into granules using a Coperion ZSK 40 twin-screw extruder (twin-screw kneader), screw diameter 40 mm, L / D = 42 (dosed proportions in mass percent): Table 5: Recipe B Connection Crowd PHBH 69,3 PBSA 29,7 Loxiol 1

[0092] The following compounding parameters were adhered to: Table 6: Temperature profile (twin screw extruder ZSK 40) Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9 Zone 10 nozzle 25 °C 105 °C 120 °C 120 °C 135 °C 155 °C 165 °C 165 °C 165 °C 160 °C 160 °C speed 100 min -1< throughput 50 kg / h Degassing - 0.98 bar, Zone 8 Water content 0,1 %

[0093] Blown films were produced from the manufactured granules. For this purpose, the granules B were processed using a single-shaft extruder of type KABRA, Screw diameter 65 mm, L / D = 23, melted and processed into a blown film.

[0094] Table 7 documents the relative decomposition of the film within a period of 72 days in seawater. Table 7: Relative decomposition of the film obtainable from granules B days decomposition 0 1 22 (2)-3 37 4 72 4 Legend:

[0095] Value Meaning 1 Foil intact 2 Decomposition visible 3 advanced decomposition 4 The foil is completely decomposed.

[0096] The mechanical properties of the film were checked. The measurements were carried out using the same equipment as in Example 1. The measurement results are listed in Table 8. Table 8: Mechanical properties of the film Film thickness [µm] Tensile strength (MD) [MPa] Tensile strength (TD) [MPa] Elongation at break (MD) [%] Elongation at Break (TD) [%] 20-55 25,3 23,9 475 544

[0097] As can be seen in Tables 7 and 8, the film made of granules B has a good combination of biodegradability in seawater and mechanical properties for use as a transport bag.

Claims

1. Film comprising 10-90 wt.% of a component A and 10-90 wt.% of a component B, based on the sum of components A and B, wherein A is a polyhydroxyalkanoate and wherein B is an aliphatic copolyester composed of at least one diol component and at least one dicarboxylic acid component, wherein the film is formed as a single-layer film, and wherein the film has a total thickness of 1 to 200 µm and at least one of the following mechanical properties: - tensile strength of the film in the dry state in the extrusion direction (MD) of at least 15 MPa according to EN ISO 527; - tensile strength of the film in the dry state transverse to the extrusion direction (TD) of at least 15 MPa according to EN ISO 527; - elongation at tear of the film in the dry state in the extrusion direction (MD) of at least 100% according to EN ISO 527; - elongation at tear of the film in the dry state transverse to the extrusion direction (TD) of at least 100% according to EN ISO 527, and wherein after introduction into salt water for a period of 12 weeks under controlled test conditions, according to the method ASTM D6691-09, and after sieving through a sieve having a mesh size of 2.0 mm, the film has a maximum of 30 wt.% of the original dry weight, and / or wherein after introduction into salt water, at least 30% of the organic carbon of the film is converted into carbon dioxide within 180 days at a temperature of 30 ± 2°C, according to the method ASTM D6691-09.

2. Film according to claim 1, characterized in that component A is selected from the group consisting of poly(3-hydroxybutanoate), poly(3-hydroxyvalerate), poly(3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hexanoate), and mixtures thereof, and / or in that component A is poly(3-hydroxybutyrate-co-3-hexanoate), and / or in that component B is an aliphatic copolyester composed of at least one diol component and at least two dicarboxylic acid components, and / or in that component B is poly(butylene adipate-co-succinate).

3. Film according to either of the preceding claims, characterized in that the film comprises 0.1 to 30 wt.%, 1 to 25 wt.%, 3 to 20 wt.%, 4 to 15 wt.%, 5 to 12 wt.%, 15 to 25 wt.%, 17 to 23 wt.% or 18 to 22 wt.% poly(butylene adipate-co-terephthalate), based on the total weight, and / or in that the film comprises 0.1 to 30 wt.%, 1 to 25 wt.%, 3 to 20 wt.%, 4 to 15 wt.%, 5 to 12 wt.%, 15 to 25 wt.%, 17 to 23 wt.% or 18 to 22 wt.% poly(butylene sebacate-co-terephthalate), based on the total weight, and / or in that the film comprises 0.1 to 30 wt.%, 1 to 25 wt.%, 3 to 20 wt.%, 4 to 15 wt.%, 5 to 12 wt.%, 15 to 25 wt.%, 17 to 23 wt.% or 18 to 22 wt.% polycaprolactone, based on the total weight, and / or in that the film comprises 0.1 to 20 wt.%, 2 to 18 wt.%, 5 to 15 wt.% or 8 to 12 wt.% starch, in particular thermoplastic starch, based on the total weight.

4. Film according to any of the preceding claims, characterized in that the film has a total thickness of 5 to 200 µm, 10 to 80 µm or 15 to 60 µm.

5. Film according to any of the preceding claims, characterized in that the film comprises 20 to 80 wt.%, in particular 25 to 75 wt.%, of component A, based on the sum of components A and B, and / or in that the film comprises 20 to 80 wt.%, in particular 25 to 75 wt.%, of component B, based on the sum of components A and B.

6. Film according to any of the preceding claims, characterized in that the film has a tensile strength in the dry state in the extrusion direction (MD) of at least 20 MPa, in particular of at least 25 MPa, according to EN ISO 527, and / or in that the film has a tensile strength in the dry state transverse to the extrusion direction (TD) of at least 20 MPa, in particular of at least 25 MPa, according to EN ISO 527, and / or in that the film has an elongation at tear in the dry state in the extrusion direction (MD) of at least 200%, at least 300% or at least 400%, according to EN ISO 527, and / or in that the film has an elongation at tear in the dry state transverse to the extrusion direction (TD) of at least 200%, at least 300% or at least 400%, according to EN ISO 527.

7. Film according to any of the preceding claims, characterized in that after introduction into salt water, at least 40%, in particular at least 50%, of the organic carbon of the film is converted into carbon dioxide within 180 days at 30 ± 2°C, according to the method ASTM D6691-09, and / or in that after introduction into salt water for a period of 12 weeks under controlled test conditions, according to the method ASTM D6691-09, and after sieving through a sieve having a mesh size of 2.0 mm, the film has a maximum of 20 wt.%, in particular a maximum of 10 wt.%, of the original dry weight, and / or in that in active decomposition conditions according to the method DIN EN ISO 14855-1:2012, at least 70%, at least 80% or at least 90% of the organic carbon of the film was converted into carbon dioxide within 180 days.

8. Use of a polymer blend containing 10-90 wt.% of a component A and 10-90 wt.% of a component B, based on the sum of components A and B, wherein A is a polyhydroxyalkanoate and wherein B is an aliphatic copolyester composed of at least one diol component and at least one dicarboxylic acid component, for producing a film, wherein the film is formed as a single-layer film having a total thickness of 1 to 200 µm and at least one of the following mechanical properties: - tensile strength in the dry state in the extrusion direction (MD) of at least 15 MPa according to EN ISO 527; - tensile strength in the dry state transverse to the extrusion direction (TD) of at least 15 MPa according to EN ISO 527; - elongation at tear in the dry state in the extrusion direction (MD) of at least 100% according to EN ISO 527; - elongation at tear in the dry state transverse to the extrusion direction (TD) of at least 100% according to EN ISO 527; and wherein after introduction into salt water for a period of 12 weeks under controlled test conditions, according to the method ASTM D6691-09, and after sieving through a sieve having a mesh size of 2.0 mm, the film has a maximum of 30 wt.% of the original dry weight, and / or wherein after introduction into salt water, at least 30% of the organic carbon of the film is converted into carbon dioxide within 180 days at a temperature of 30 ± 2°C, according to the method ASTM D6691-09.

9. Use according to claim 8, characterized in that component A is as defined in claim 2 and / or in that component B is as defined in claim 2, and / or in that the polymer blend contains 20 to 80 wt.%, in particular 25 to 75 wt.%, of component A, based on the sum of components A and B, and / or contains 20 to 80 wt.%, in particular 25 to 75 wt.%, of component B, based on the sum of components A and B.

10. Transport bag containing a film according to any of claims 1 to 7.

11. Transport bag according to claim 10, characterized in that the transport bag is selected from the group consisting of carrier bag, fruit bag, vegetable bag, light T-shirt bag and ultra-light T-shirt bag, and / or in that the transport bag has a weight of 1 to 90 g, 2 to 50 g, 20 to 40 g, 1 to 10 g or 1.5 to 5 g.

12. Method for producing a film according to any of claims 1 to 7, characterized by the following steps: a. providing a polymer blend containing 10-90 wt.% of a component A and 10-90 wt.% of a component B, based on the sum of components A and B, A being a polyhydroxyalkanoate and B being an aliphatic copolyester composed of at least one diol component and at least one dicarboxylic acid component; b. forming a film from the polymer blend according to step a, the film being formed as a single-layer film, and the film having a total thickness of 1 to 200 µm and at least one of the following mechanical properties: - tensile strength of the film in the dry state in the extrusion direction (MD) of at least 15 MPa according to EN ISO 527; - tensile strength of the film in the dry state transverse to the extrusion direction (TD) of at least 15 MPa according to EN ISO 527; - elongation at tear of the film in the dry state in the extrusion direction (MD) of at least 100% according to EN ISO 527; - elongation at tear of the film in the dry state transverse to the extrusion direction (TD) of at least 100% according to EN ISO 527, and after introduction into salt water for a period of 12 weeks under controlled test conditions, according to the method ASTM D6691-09, and after sieving through a sieve that has a mesh size of 2.0 mm, the film having a maximum of 30 wt.% of the original dry weight, and / or after introduction into salt water, at least 30% of the organic carbon of the film being converted into carbon dioxide within 180 days at a temperature of 30 ± 2°C, according to the method ASTM D6691-09.

13. Method according to claim 12, characterized in that component A is as defined in claim 2 and / or in that component B is as defined in claim 2, and / or in that the polymer blend contains 20 to 80 wt.%, in particular 25 to 75 wt.%, of component A, based on the sum of components A and B, and / or contains 20 to 80 wt.%, in particular 25 to 75 wt.%, of component B, based on the sum of components A and B.

14. Use of a film according to any of claims 1 to 7 for producing a transport bag.