Flexible multi-layer film with high cold impact strength for medical packaging

Description

[0001] The invention relates to heat-sterilizable multilayer films based on aliphatic polyolefins which have particularly good impact resistance at low temperatures, a process for their production and their use for medical packaging.

[0002] Multilayer films have been used in a wide range of applications for many years, for example in the food industry but also in the medical / pharmaceutical sector, for example as secondary packaging (outer packaging) or primary packaging for solution bags, dry concentrates and medications in tablet form.

[0003] Some multilayer films can be processed into flexible packaging, which is suitable, for example, as bags for packaging and administering medical solutions. Currently, medical solutions, such as infusion solutions for parenteral administration, are commonly found on the market in flexible disposable bags made of polyvinyl chloride (PVC) or non-PVC materials.

[0004] In addition to the ability to collapse, which ensures complete leakage, these bags must meet other performance criteria such as transparency, hot steam sterilization capability at 121°C, sufficient mechanical strength, especially under dynamic loading in the weld area, a good water vapor barrier, resilience for common pressure cuff applications such as pressure infusions, and, from a pharmaceutical perspective, minimal impact on the bag contents. Multilayer films with a polyolefin-based layer structure have proven advantageous in meeting these properties.

[0005] US Patent 5,681,627 describes multilayer films - for medical applications such as medical bags - comprising a) a first outer layer containing polyurethane (PU); b) a second outer layer (inner surface of a bag, sealing layer), preferably made of a blend of PP homopolymer or copolymer and elastomer; and c) a middle layer made of a polymeric adhesion promoter, preferably an ethylene / α-olefin copolymer. A blend of a propylene / ethylene copolymer (80%) and an SEBS block copolymer (20%) is preferably used as the second outer layer.

[0006] US Patent 5,695,840 describes 5-layer multilayer films - for medical applications such as medical bags - containing a) a first layer (inner surface of a bag, sealing layer) made of a blend of PP homo- or copolymer and elastomer; b) a second (middle) layer adjacent to a) made of an ethylene / alpha-olefin copolymer; c) a third (middle) layer adjacent to b) (ethylene / alpha-olefin copolymer); d) a fourth adhesion-promoting layer adjacent to c) (anhydride-modified copolymers); and e) a fifth layer (outer layer) made of a polyamide or copolyester.

[0007] US Patent 5,783,269 discloses heat-sterilizable multilayer films for the production of medical bags, comprising an outer layer (2), a carrier layer (4), a flexible middle layer (3), and optionally a heat-sealing layer (5), wherein all layers contain polyolefin homopolymers and / or copolymers (softening temperature: (2) and (4) > 121°C, (3) < 70°C). Exemplary 4-layer films are composed of: (2) and (4) PP homopolymer, (3) PE or PP copolymer, (5) PP copolymer.

[0008] EP-A 0229475 describes a multilayer film for medical containers, which is preferably 3-layered, comprising (a) a first (= inner) heat-sealable layer made of a mixture of (i) polypropylene, (ii) an ethylene copolymer and (iii) a modifier such as another ethylene copolymer or an elastomer (e.g. EPDM terpolymer, SBS, SEBS, and SIS copolymer); (b) a second (middle) layer made of a mixture of (i) polyethylene (PE) (50 to 90 wt.%) and (ii) a modifier; and (c) a third (outer) layer made of a mixture of (i) polypropylene and (ii) a modifier. Modified PP copolymers are preferably used for the outer layer.

[0009] EP-A 0199871 describes a flexible, inter alia, three-layer multilayer film for medical bags, comprising: (a) an (inner) sealing layer containing an (optionally modified) ethylene-propylene copolymer (ethylene content: 3.8 wt%); (b) a middle layer of a flexible polymer material (e.g., an elastomeric co- or terpolymer such as EPDM); and (c) an outer layer containing an ethylene-propylene copolymer.

[0010] DE-A 10361851 and WO 2020 / 127227 A1 describe a heat-sterilizable 3-layer multilayer film for the production of medical bags, the outer layer of which consists of polypropylene homopolymer modified with impact modifiers (at least 70 wt.%, example 97 wt.%), the middle layer of which consists of polypropylene terpolymer modified with impact modifiers, and the (sealable) inner layer of polypropylene terpolymer and / or polypropylene copolymer modified with impact modifiers. Suitable impact modifiers are styrene-ethylene / butylene (SEBS), styrene-ethylene / propylene (SEPS) block copolymers, or ethylene / α-olefin copolymers. The middle layer can contain 20 to 80 wt.% PP terpolymer, 0 to 40 wt.% polyethylene copolymer, 0 to 60 wt.% SEB or SEP block copolymer. Exemplary films have a middle layer of 75 wt.% PP terpolymer, 20 wt.% SEBS block copolymer, and 5 wt.% PE plastomer (ethylene / octene copolymer), and an inner layer of 85 or 75 wt.% PE plastomer.-% PP terpolymer, 15 or 20 wt.% SEB block copolymer and 0 or 5 wt.% PE plastomer.

[0011] DE 203 20 212 U1 describes a heat-sterilizable 3-layer multilayer film produced by coextrusion for use in medical bags. Exemplary films have an outer layer composed of 97 wt.% polypropylene homopolymer and 3 wt.% SEBS block copolymer, a middle layer composed of 80 wt.% EXCELLEN—a heterophasic copolymer based on polypropylene and polyethylene—and 20 wt.% SEBS block copolymer, and an inner layer composed of 75 wt.% PP terpolymer, 20 wt.% SEBS block copolymer, and 5 wt.% PE plastomer.

[0012] Although good results have already been achieved with the known films in terms of flexibility, heat sterilization capability and transparency, these films still need to be improved, particularly with regard to impact resistance, especially at lower temperatures, often 4 to -70°C, and especially -18 to -40°C, and are only inadequately suitable for medical packaging that is stored in the refrigerator or freezer.

[0013] Materials available on the market for deep-freeze applications include packaging (e.g., bags) made of pure polyethylene (e.g., for food) or polyvinyl chloride (e.g., for blood plasma). PE bags, which have very good cold impact resistance, have the disadvantage that they are not suitable for heat sterilization at 121°C, as required for medical films. Materials containing PVC are considered harmful to health because they typically contain plasticizers that often escape, so attempts are being made to replace PVC with alternative materials. This is especially true for medical packaging and packaging that is stored in the refrigerator or freezer.

[0014] The object of the invention is therefore to provide a heat-sterilizable multilayer film for medical packaging requiring particularly good low-temperature impact strength, which does not have the aforementioned disadvantages. Furthermore, the multilayer film or packaging made from it should retain properties such as high transparency, hot steam sterilizability at 121°C, sufficient mechanical strength, especially under dynamic loading in the weld seam area, a good water vapor barrier, load-bearing capacity for common pressure cuff applications, e.g., pressure infusion, and the ability of bags to collapse.

[0015] A further object of the invention is to provide a method for producing the heat-sterilizable multilayer film, in particular a method for producing a film tube based on the heat-sterilizable multilayer film.

[0016] One object of the invention is a heat-sterilizable multilayer film comprising (consisting of) a) a first polymer layer (A) containing (consisting of) at least one, preferably one, polypropylene homopolymer modified with at least one, preferably one, impact modifier; b) a second polymer layer (B) containing (consisting of): B1) 51 to 68 wt.% - based on (B) - of at least one polypropylene terpolymer; B2) 12 to 22 wt.% - based on (B) - of at least one styrene block copolymer (SBC) elastomer; B3) 15 to 35 wt.% - based on (B) - of at least one propylene-ethylene (block) copolymer, wherein - based on (B3) - the proportion of structural units of ethylene ≥ 9 wt.%, often 9 to 15 wt.%, preferably ≥ 10 wt.%; and c) a middle polymer layer (C) located between the first polymer layer (A) and the second polymer layer (B), containing (consisting of): C1) 20 to 30 wt.% - based on (C) - of at least one styrene block copolymer (SBC) elastomer; C2) 15 to 30 wt.-% - based on (C) - of at least one polyethylene elastomer which is a copolymer of ethylene with an alpha-olefin containing 4 to 12 carbon atoms; C3) 40 to 65 wt.% - based on (C) - of at least one propylene-ethylene (block) copolymer, wherein - based on (C3) - the proportion of structural units of ethylene is ≥ 9 wt.%, often 9 to 15 wt.%, preferably ≥ 10 wt.%.

[0017] The proportions given in weight percent (wt%) each add up to 100 wt%.

[0018] For the purposes of the present invention, the structural units of a monomer in a (co)polymer are understood to mean the structural units derived from the polymerized monomer.

[0019] The term "heat-sterilizable" means that the corresponding materials can be sterilized at elevated temperatures, preferably steam sterilization. Sterilization refers to processes by which materials and objects are freed of living microorganisms. The resulting state of the materials and objects is referred to as "sterile." Steam sterilization of filled or unfilled medical packaging uses hot steam for sterilization, which is typically carried out in an autoclave. The medical packaging is heated in steam, preferably for 20 minutes, to 121°C at 2 bar pressure. The air inside the autoclave is completely replaced with steam.

[0020] The term "multilayer film" refers to thermoplastic materials in several coextruded polymer layers that are bonded together to form a film in the form of a continuous web or tube.

[0021] The term "impact modifier" refers to polymeric materials, such as styrene block copolymer elastomers, polyethylene elastomers and polypropylene elastomers, which improve the impact resistance of the polymer surrounding the impact modifier by blending them in the melt state.

[0022] The term "impact strength" refers to the ability of a material to withstand dynamic loading. According to DIN EN ISO 180:2013-08, the Izod impact strength of plastics can be measured under specified conditions. First polymer layer (A)

[0023] The first polymer layer (A) of the multilayer film according to the invention is, by definition, the polymer layer located on the outside of the packaging when the film is processed into a package, which is preferably a bag. Accordingly, during further processing of the film into packaging, it is in direct contact with the surface of the welding tool and therefore preferably requires a high melting or softening temperature, which is preferably above 125°C, more preferably between 127°C and 150°C, and most preferably between 130°C and 145°C.

[0024] The first polymer layer (A) contains at least one, preferably one, polypropylene homopolymer which is modified with at least one, preferably one, impact modifier.

[0025] Preferably, the first polymer layer (A) consists of at least one, preferably one, polypropylene homopolymer which is modified with at least one, preferably one, impact modifier.

[0026] Further preferably, the first polymer layer (A) contains a polypropylene homopolymer which is modified with an impact modifier.

[0027] The first polymer layer (A) contains (or consists of) at least one, preferably one, polypropylene homopolymer which is modified to improve the (cold) impact strength generally with 1 to 30 wt.%, preferably with 2 to 20 wt.%, particularly preferably 2 to 10 wt.%, in particular 3 to 5 wt.%, of at least one impact modifier.

[0028] The production of polypropylene homopolymers is well known. Furthermore, polypropylene homopolymers are commercially available, for example, from Lyondell Basell Corporation, USA.

[0029] The first polymer layer (A) preferably contains (or consists of) a polypropylene homopolymer which is modified with at least one impact modifier selected from the group of styrene block copolymers, such as styrene-ethylene-butylene-styrene block copolymers (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-isoprene-styrene block copolymer (SIS), and styrene-butadiene-styrene block copolymer (SBS), preferably SEBS and SEPS, in particular SEBS, and / or from the group of copolymers of ethylene with at least one alpha-olefin containing 4 to 16, preferably 4 to 12, particularly preferably 4 to 8 carbon atoms, such as ethylene-butylene copolymers and / or ethylene-octene copolymers.

[0030] Particularly preferably, the first polymer layer (A) contains (or consists of) 90 to 98 wt.%, in particular 95 to 97 wt.%, of a polypropylene homopolymer and 2 to 10 wt.%, in particular 3 to 5 wt.%, of a styrene block copolymer and / or a copolymer of ethylene with at least one alpha-olefin containing 4 to 12, preferably 4 to 8, carbon atoms.

[0031] In a preferred embodiment, the first polymer layer (A) contains (or consists of) 95 to 97 wt.% of a polypropylene homopolymer and 3 to 5 wt.% of a styrene-ethylene / butylene block copolymer.

[0032] The weight specifications for the components of the first polymer layer (A) refer to the total weight of the first polymer layer (A). Second polymer layer (B)

[0033] The second polymer layer (B) is, by definition, the polymer layer which, when the multilayer film according to the invention is processed into a package, which is preferably a bag, is located on the inside of the package. This polymer layer is responsible for ensuring that the package can be tightly closed by welding. The second polymer layer (B) of the film must be able to be welded securely to itself and to appropriately inserted port elements at the lowest possible temperature and welding time, and yet be heat-sterilizable at temperatures above 121°C. A low welding temperature is particularly important in order to subject the film structure to as little structural stress as possible. Accordingly, the melting or softening temperature of the second polymer layer (B) is generally above 121°C, preferably between 122°C and 135°C, particularly preferably between 124°C and 130°C, but in any case below the melting or softening temperature.Softening temperature of the first polymer layer (A).

[0034] The second polymer layer (B) of the multilayer film according to the invention contains (or consists of) components B1), B2) and B3) in the following proportions (each based on (B)): B1) 51 to 68% by weight, preferably 55 to 67% by weight, particularly preferably 56 to 66% by weight; B2) 12 to 22% by weight, preferably 13 to 21% by weight, particularly preferably 14 to 20% by weight; B3) 15 to 35% by weight, preferably 17 to 32% by weight, particularly preferably 18 to 30% by weight. Component B1)

[0035] Component B1) is at least one, preferably one, polypropylene terpolymer. The term "terpolymer" refers to a copolymer made from three different monomers.

[0036] The term "polypropylene terpolymer" refers to a polypropylene molecular chain modified with two additional comonomers during the polymerization process. Preferred additional comonomers are ethylene and / or at least one C4-C12 α-olefin, preferably ethylene and a C4-C12 α-olefin, more preferably ethylene and a C4-C8 α-olefin, most preferably ethylene and 1-butene.

[0037] Preferably, B1) is a terpolymer of propylene, ethylene and a C 4 -C 12 α-olefin, wherein the proportion of ethylene is preferably 1 to 4 wt.% and the proportion of the C 4 -C 12 α-olefin, preferably C 4 -C 8 α-olefin, in particular 1-butene, is preferably 9 to 12 wt.%, in each case based on (B1).

[0038] The weight fractions refer to the polymerized structural units of the monomers in the terpolymer (B1).

[0039] The polypropylene terpolymer (component B1)) is particularly preferably composed of structural units of propylene, ethylene and butylene.

[0040] The monomers are generally incorporated randomly in the polypropylene terpolymer (= component B1), ie polypropylene terpolymer B1) is usually a random polypropylene terpolymer.

[0041] The polypropylene terpolymer B1) is modified with components B2) and B3), which act as impact modifiers, to improve impact strength, especially at low temperatures. Component B2)

[0042] Component B2) is at least one, preferably one, styrene block copolymer (SBC) elastomer.

[0043] The term "styrene block copolymer elastomer" refers to synthetic thermoplastic elastomers based on styrene block copolymers for the impact modification of polypropylene.

[0044] The at least one styrene block copolymer (SBC) elastomer B2) is preferably selected from the group consisting of: styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-isoprene-styrene block copolymer (SIS) and styrene-butadiene-styrene block copolymer (SBS), and particularly preferably SEBS and SEPS, in particular SEBS.

[0045] It is also possible to partially replace the styrene block copolymer (SBC) elastomer by one or more olefin-based thermoplastic elastomers (TPE-O) (TPE-O proportion: maximum 45 wt.%, preferably 20 to 30 wt.%).

[0046] Preferably, component B2) is a styrene block copolymer (SBC) elastomer which does not contain any portions of an olefin-based thermoplastic elastomer. Component B3)

[0047] Component B3) is at least one, preferably one, propylene-ethylene (block) copolymer, wherein - based on (B3) - the proportion of structural units of ethylene is ≥ 9 wt.%, often 9 to 15 wt.%, preferably ≥ 10 wt.%, often preferably 10 to 12 wt.%.

[0048] Propylene-ethylene copolymers B3) are often also referred to as "heterophasic" copolymers. In general, the propylene-ethylene copolymer B3) is a propylene-ethylene block copolymer that contains ethylene and propylene polymer blocks and therefore forms a heterogeneous phase (morphology). Heterophasic propylene-ethylene (block) copolymers B3) differ both in their composition (proportion of ethylene structural units ≥ 9 wt.%) and in their properties from propylene-ethylene copolymers with a random distribution of the two monomers—not used according to the invention as component B3)—in which the proportion of ethylene structural units is generally a maximum of 8 wt.%, often a maximum of 5 wt. Such random propylene-ethylene copolymers typically form a homogeneous phase (morphology).

[0049] Preferably, the second polymer layer (B) according to the invention contains (or consists of): a polypropylene terpolymer (component B1) composed of structural units of propylene, ethylene and butylene, a styrene-ethylene-butylene-styrene block copolymer (SEBS) (component B2), and a propylene-ethylene (block) copolymer (component B3).

[0050] Particularly preferably, the second polymer layer (B) according to the invention contains (or consists of): B1) 55 to 67% by weight, preferably 56 to 66% by weight, of a polypropylene terpolymer composed of structural units of propylene, ethylene, and butylene; B2) 13 to 21% by weight, preferably 14 to 20% by weight, of a styrene-ethylene-butylene-styrene block copolymer (SEBS); and B3) 17 to 32% by weight, preferably 18 to 30% by weight, of a propylene-ethylene (block) copolymer (component B3).

[0051] The weight specifications for components B1), B2) and B3) of the second polymer layer (B) refer to the total weight of the second polymer layer (B). Middle polymer layer (C)

[0052] The middle polymer layer (C) has the largest mass fraction (at least 50 wt.%) of the multilayer film, preferably 60 to 95 wt.%, particularly preferably 70 to 90 wt.%, very particularly preferably 75 to 85 wt.% of the entire multilayer film and serves to improve the impact strength of the entire structure.

[0053] The middle polymer layer (C) of the multilayer film according to the invention contains (or consists of) the components C1), C2) and C3) in the following proportions (each based on (C)): C1) 20 to 30 wt.%, preferably 21 to 30 wt.%, particularly preferably 22 to 27 wt.%; C2) 15 to 30 wt.%, preferably 15 to 25 wt.%, particularly preferably 17 to 23 wt.%, C3) 40 to 65 wt.%, preferably 45 to 65 wt.%, particularly preferably 50 to 60 wt.%, very particularly preferably 52 to 57 wt.%. Component C1)

[0054] Component C1) is at least one, preferably one, styrene block copolymer (SBC) elastomer.

[0055] Styrene block copolymer (SBC) elastomer C1) is defined in the same way as component B2), so reference is made to the corresponding explanations for component B2). Component C2)

[0056] Component C2) is at least one, preferably one, polyethylene elastomer which is a copolymer of ethylene with an alpha-olefin containing 4 to 12, preferably 4 to 8, carbon atoms.

[0057] The proportion of structural units of the alpha-olefin - based on (C2) - is preferably 20 to 30 wt.%.

[0058] The polyethylene elastomer C2) is particularly preferably an ethylene-butylene copolymer and / or an ethylene-1-octene copolymer, in particular an ethylene-1-octene copolymer. Component C3)

[0059] Component C3) is at least one, preferably one, propylene-ethylene (block) copolymer, wherein - based on (C3) - the proportion of structural units of ethylene is ≥ 9 wt.%, often 9 to 15 wt.%, preferably ≥ 10 wt.%, often preferably 10 to 12 wt.%.

[0060] Propylene-ethylene (block) copolymer C3) is defined in the same way as component B3), so reference is made to the corresponding statements on component B3).

[0061] Preferably, the middle polymer layer (C) according to the invention contains (or consists of) a styrene-ethylene-butylene-styrene block copolymer (SEBS) (component C1)), an ethylene-1-octene copolymer (component C2)), and a propylene-ethylene (block) copolymer (component C3)). Particularly preferably, the middle polymer layer (C) according to the invention contains (or consists of)

[0062] C1) 21 to 30 wt.%, preferably 22 to 27 wt.%, of a styrene-ethylene-butylene-styrene block copolymer (SEBS); C2) 15 to 25 wt.%, preferably 17 to 23 wt.%, of an ethylene-octene copolymer; and C3) 45 to 65 wt.%, preferably 50 to 60 wt.%, of a propylene-ethylene (block) copolymer (component C3)).

[0063] The weight specifications for components C1), C2) and C3) of the middle polymer layer (C) refer to the total weight of the middle polymer layer (C). Functional layer (D)

[0064] The heat-sterilizable multilayer film according to the invention may further comprise an additional functional layer D) as an outer layer, which is located adjacent to the first polymer layer (A) on the outer side of (A) - ie on the other side of (A) opposite to that with polymer layer (C).

[0065] Functional layer (D) preferably ensures that the heat-sterilizable multilayer film, as well as packaging made therefrom, such as medical bags or film tubes made therefrom, are gas-tight and / or waterproof. Functional layer D) contains, preferably consists of, at least one, preferably one, material selected from the group consisting of: ethylene-vinyl alcohol copolymers, polyvinyl alcohols, polyamides, liquid-crystalline polymers (LCP), aromatic polyesters, preferably terephthalic acid polyesters, particularly preferably polyethylene terephthalates (PET), silicon oxide (SiO x ), aluminum oxide (Al O x ), and acrylate-based polymers.

[0066] The functional layer (D) preferably consists of PET / SiO x .

[0067] The functional layer (D) preferably has a layer thickness of 5 to 25 µm, in particular of 10 to 20 µm.

[0068] By means of a functional layer (D) made of PET / SiO x , the gas barrier (e.g. the oxygen barrier) of the heat-sterilizable multilayer film according to the invention is significantly improved, so that the film is also well suited for the storage of oxygen-sensitive ingredients.

[0069] By means of a SiO x / PET functional layer (D), the oxygen barrier (oxygen transmission rate (OTR)) of the heat-sterilizable multilayer film according to the invention can be reduced by a factor of 1000 to OTR values ​​< 1 cm 3 < / (m 2 < x day) ASTM F1927 (23°C, 50% rH). Multilayer film

[0070] Preferably, the heat-sterilizable multilayer film according to the invention consists of the polymer layers (A), (B) and (C).

[0071] The multilayer film may contain, in each of the polymer layers (A), (B) and (C), conventional additives and / or processing aids suitable for the intended use of the multilayer film in conventional amounts.

[0072] Preferred additives are antioxidants and thermal stabilizers (phosphitic and phenolic stabilizers such as Irgafos ®< 168, Irgafos P-EPQ , Irganox ®< 1076 or Irganox 1010), as well as acid scavengers such as DHT-4A ®< , synthetic hydrotalcite (SHT) and magnesium oxide (MgO).

[0073] Preferably, the heat-sterilizable multilayer film made of the polymer layers (A), (B) and (C) according to the invention contains at least one antioxidant, thermal stabilizer and / or acid scavenger, preferably in a total amount of < 3000 ppm, based on the entire multilayer film.

[0074] Preferably, the polymer layers (A), (B) and (C) adhere to one another without the use of an adhesion promoter, i.e. the multilayer film according to the invention comprising the polymer layers (A), (B) and (C) preferably does not contain an adhesion promoter. Furthermore, at least the second polymer layer (B) preferably contains no further additives and / or processing aids (e.g. modifiers or plasticizers, such as mineral oil), with very particular preference for none of the polymer layers (A), (B), and (C) containing further additives and / or processing aids in addition to the additives mentioned above as preferred. Accordingly, the medicament or the medical solution is hardly or not influenced by the multilayer film according to the invention as a packaging material during sterilization and storage.

[0075] In the case of a multilayer film according to the invention consisting of the polymer layers (A), (B), (C) and the functional layer (D), the multilayer film generally contains, in addition to the additives mentioned above as preferred, an adhesion promoter or pressure-sensitive adhesive.

[0076] The layer thickness of the first polymer layer (A) is generally 5 to 15 wt.%, preferably 7 to 13 wt.%, particularly preferably 7.5 to 10 wt.%, of the total film thickness of the multilayer film according to the invention.

[0077] The layer thickness of the second polymer layer (B) is generally 5 to 15 wt.%, preferably 7 to 13 wt.%, particularly preferably 7.5 to 10 wt.%, of the total film thickness of the multilayer film according to the invention.

[0078] The middle polymer layer (C) has the largest proportion (preferably at least 70 wt.% of the total film thickness) of the multilayer film according to the invention and serves to improve the impact strength of the entire structure.

[0079] In a multilayer film consisting of (A), (B) and (C), the layer thickness of the middle polymer layer (C) is generally 70 to 85 wt.%, preferably 74 to 80 wt.%.

[0080] If present, the layer thickness of the optional functional layer (D) is preferably 2.5 to 12.5 wt.%, particularly preferably 5 to 10 wt.%, of the total film thickness of the multilayer film according to the invention.

[0081] The total film thickness of the multilayer film according to the invention is preferably 50 to 500 µm, particularly preferably 100 to 400 µm, most preferably 150 to 300 µm.

[0082] The total film thickness of a multilayer film according to the invention consisting of the polymer layers (A), (B) and (C) is preferably 50 to 500 µm, particularly preferably 100 to 400 µm, very particularly preferably 150 to 300 µm.

[0083] Particularly preferred is a multilayer film according to the invention which consists of the polymer layers (A), (B) and (C), and is characterized in that the total film thickness of the multilayer film is 50 to 500 µm, particularly preferably 100 to 400 µm, and - in each case based on the total film thickness of the multilayer film - the layer thickness of the first polymer layer (A) is 5 to 15 wt.%, preferably 7 to 13 wt.%, the layer thickness of the second polymer layer (B) is 5 to 15 wt.%, preferably 7 to 13 wt.%; and the layer thickness of the middle polymer layer (C) is 70 to 85 wt.%, preferably 74 to 80 wt.%; and the proportions of (A), (B) and (C) each together add up to 100 wt.%. Process for producing the multilayer film

[0084] Another object of the invention is a process for producing the multilayer film according to the invention, wherein the first polymer layer (A), the middle polymer layer (C), and the second polymer layer (B) are coextruded.

[0085] In coextrusion, the plastic melts of the polymer layers (A), (B) and (C) are combined to form the multilayer film according to the invention before leaving the profile die of an extruder.

[0086] The extrusion process is often two-stage. In a first step, the materials used for the individual polymer layers are mixed and compacted in extruders, preferably parallel twin-screw extruders (compounders), heating-cooling mixers, or pelletizing presses. Then, the plastic melts of polymer layers (A), (B), and (C) are combined in another, directly coupled or spatially and temporally separated extruder before leaving the profile die to form the multilayer film according to the invention.

[0087] Preferably, the multilayer film obtained by the process according to the invention is shock-cooled with water.

[0088] By coextrusion, the multilayer film according to the invention can be obtained in the form of a flat film (flat film process, e.g. when using a slot die) or a film tube (blown film process, e.g. flooding the interior of the film tube with - preferably sterile filtered - air), wherein in the case of a film tube the outside consists of the first polymer layer (A) and the inside of the second polymer layer (B).

[0089] In a further process step, the optional functional layer (D) can be applied to the multilayer film obtained by the process according to the invention - e.g. by hot lamination or preferably by laminating.

[0090] According to a particular embodiment for producing a laminated multilayer film tube according to the invention, the method according to the invention comprises the following steps: (a')) producing a film tube from the multilayer film according to the invention by a blown film process, wherein the interior of the film tube is flooded with - preferably sterile-filtered - air; (b')) optionally cooling the film tube produced in process step (a'); (c')) coating the optionally cooled film tube with a pressure-sensitive adhesive layer on at least one side (first polymer layer (A)) of the film tube; (d')) optionally drying the film tube provided with the pressure-sensitive adhesive layer; (e')) laminating the at least one side (first polymer layer (A)) of the film tube coated with the pressure-sensitive adhesive layer with a functional layer (D), in particular a SiOx / PET functional layer; (f) optionally drying or curing the laminated film tube.

[0091] According to the inventive method of the aforementioned embodiment, the two parallel inner sides (= second polymer layer (B)) of the film tube preferably adhere directly to one another after melt-extrusion or coextrusion of the film tube, so that coating of the outer sides (first polymer layers (A)) of the film tube is possible while maintaining a closed interior of the film tube. The closed interior, which is expanded during subsequent use of the resulting film tube, is thus essentially particle-free.

[0092] Preferably, in the method according to the invention of the aforementioned embodiment, the interior of the film tube is flooded with sterile filtered air, so that a low-particle, laminated multilayer film tube is obtained which is particularly well suited for medical purposes.

[0093] For the production of a low-particle, laminated multilayer film tube, the above-mentioned process according to the invention is particularly preferably carried out in a clean room.

[0094] In the process according to the invention according to the above embodiment, a bonding agent is preferably used that enables complete curing at room temperature after approximately 2 weeks, preferably 1 week. In a heat chamber, curing can also occur more quickly at elevated temperatures, preferably 30°C or more, often 40°C to 60°C.

[0095] Suitable adhesion promoters (pressure-sensitive adhesives, adhesive glues or laminating adhesives) include, for example, isocyanates, polyurethanes, poly(ethyl acrylate / methacrylic acid ester), pure acrylate copolymers, vinyl ester / acrylate copolymers or inorganic-organic hybrid polymers.

[0096] Preferred adhesion promoters are two-component systems, which can be solvent-based or solvent-free, and silane-based or silane-free, and can optionally be used with an additional "catalyst" to accelerate curing.

[0097] Suitable solvent-based two-component systems include polyurethane adhesives and commercially available systems such as Dow ADCOTE ™< 675A + ADCOTE ™< 675C coreactant; Dow ADCOTE 811A + ADCOTE 811B coreactant; Dow ADCOTE E735A-75 + ADCOTE ™< E735C2 coreactant: MORCHEM PS 241 AE + CS-97 coreactant, Henkel Loctite Liofol LA2798 + Henkel Loctite Liofol LA7371; Henkel LOCTITE HY 4070 2K hybrid adhesive.

[0098] The above systems can optionally be used with "Catalysts" such as Dow Catalyst 9L10 (polyisocyanate), Dow Catalyst 9L200 and Dow Catalyst F Adcote 40-3E, which are commercially available.

[0099] Suitable solvent-free two-component systems include polyurethane adhesives and commercially available systems such as Dow MOR-FREE ™< L 75-720 Adhesive + CR 88-720 or CR 88-721 or MOR-FREE ™< C 79 S coreactant Dow MOR-FREE ™< 203A Adhesive + MOR-FREE ™< 200C coreactant Dow MOR-FREE ™< L705 Adhesive + MOR-FREE ™< C 79 or MOR-FREE ™< C-102 coreactant.

[0100] Alternatively, one-component systems can be used as adhesion promoters, which can be solvent-based or solvent-free, and silane-based or silane-free, and can optionally be used with an additional "catalyst" to accelerate curing.

[0101] Suitable solvent-free one-component systems are, for example, Dow MOR-FREE ™< ELM 415A (polyurethane adhesive) or SENOBOND ®< -WB-FOIL LAMINATION ADHESIVE FP NDC 375224, which are commercially available.

[0102] Particularly preferably, the adhesive is selected so that it complies with the requirements of pharmacopoeia limits, for example with regard to migration properties, and is preferably free of organic solvents.

[0103] Depending on the process or the desired coating, the adhesive layer can be applied to one or both sides of the coextruded film tube. This can be done, for example, by spraying or doctoring. Aqueous solutions of the corresponding adhesives are also suitable.

[0104] After applying these adhesive layers, the resulting film tube can be dried if desired. For example, if the adhesive is applied using water, drying can occur by evaporation of the water. The layer thicknesses of the pressure-sensitive adhesive layers are preferably in the range of 1 to 10 µm.

[0105] The invention also relates to the use of the multilayer film according to the invention for producing a medical packaging, preferably a medical bag.

[0106] The medical packaging according to the invention is particularly suitable as a container for at least one medicament, wherein due to the specially modified polymer layer (C), the multilayer film according to the invention is particularly also suitable for packaging and storing medical solutions at sub-zero temperatures.

[0107] In a preferred embodiment, the packaging according to the invention is divided into compartments so that it can be used as a container for multiple medications simultaneously. This is relevant, for example, for medication combinations that must be administered together but are not stable in combination over extended periods, or for solid medications that are administered in the form of a solution or suspension but are not stable in the solution or suspension over extended periods. Separate compartments allow the components of the final dosage form to be stored separately and mixed together shortly before administration by opening the separation points.

[0108] A method for producing a medical package according to the invention, preferably a bag, comprises the steps: a) Providing at least one heat-sterilizable multilayer film according to the invention; b) Optionally providing one or more port elements and / or tubes; c) Forming a medical package, preferably a bag, from the at least one heat-sterilizable multilayer film, such that the second polymer layer (B) forms the inner surface of the medical package, preferably the bag, and the first polymer layer (A) forms the outer surface of the medical package, preferably the bag; d) Optionally positioning the port elements and / or tubes between the inner surfaces at the contours of the medical package, preferably the bag; e) Bringing the inner surfaces at the contours of the medical package, preferably the bag, into contact with each other and with any port elements and / or tubes positioned therebetween;f) welding the inner surfaces to the contours of the medical packaging, preferably the bag, together and with any port elements and / or tubes positioned therebetween;

[0109] In step a), the multilayer film according to the invention is preferably provided in the form of a flat film or a tubular film. Depending on the form of the film provided, the further process may differ in certain details. The resulting low-particle film tubular can be laminated with a functional layer (D), e.g., a SiOx / PET functional layer, in additional process steps.

[0110] Depending on the application of the medical packaging according to the invention, preferably the bag, additional elements such as port elements and / or tubes can optionally be provided in step b) after the multilayer film according to the invention has been provided. The provision of these elements is useful, for example, if the medical packaging according to the invention, preferably the bag, is to be used as an integral part of a medical device or is to be connected to a medical device. Omitting step b) can be useful, for example, if the medical packaging, preferably the bag, is only used to store a medication and is damaged to remove the medication, for example by tearing it open or piercing it with a cannula.

[0111] In step c), the provided multilayer film according to the invention is brought into the shape of a medical package, preferably a bag. If a tubular film was provided in step a), the forming of the medical package, preferably the bag, can, for example, only involve cutting the tubular film to the desired length, since the second polymer layer (B) already forms the inner surface of the tubular film and the first polymer layer (A) forms the outer surface of the tubular film. If a flat film was provided in step a), the medical package, preferably the bag, can, for example, be formed from a piece of multilayer film in step c) by cutting this piece into a mirror-symmetrical shape and folding it along the mirror axis so that the edges of the film lie congruently on top of one another, with the second polymer layer (B) on the inside.Alternatively, the medical packaging according to the invention, preferably the bag, can be formed, for example, from two pieces of flat film by cutting the two pieces mirror-symmetrically to each other and placing them congruently on top of each other, with the second polymer layer (B) on the inside. Rectangular shapes are particularly preferred for cutting, as this minimizes material loss and simplifies processing. However, other shapes are also possible, so that, for example, a medical packaging, preferably a bag, can be produced with an aesthetic shape that is appealing to children and distracts them from the actual administration of a medication.

[0112] Depending on whether additional elements such as port elements and / or tubes were provided in step b), these elements can be positioned in step d) between the inner surfaces on the contours of the shaped medical packaging, preferably the bag. In the case of a tubular film, this means inserting the additional elements into the openings of the tubular film. The elements can only be positioned on two opposite sides of the medical packaging, preferably the bag. In the case of a flat film, this means inserting the additional elements between the edges of the one or more flat film pieces placed congruently on top of one another in step c). The elements can be positioned at any desired location along the edges, preferably at most on two opposite edges.

[0113] In step e), the inner surfaces of the shaped medical packaging, preferably the bag, are brought into contact with each other along its contours and with any additional elements located between the inner surfaces, so that they can be welded together in step f) by applying heat and, if appropriate, mechanical pressure. During the welding process, the temperature is preferably selected such that it is above the melting or softening point of the second polymer layer (B), but below the melting or softening point of the first polymer layer (A). This ensures that the second polymer layer (B) melts along the contours of the medical packaging, preferably the bag, and thereby seals it firmly and fluid-tight, while the first polymer layer (A) retains its shape and thus maintains the stability of the medical packaging, preferably the bag.

[0114] An important criterion for the use of the multilayer film according to the invention as primary packaging for medical solutions is its barrier effect against liquid loss. Such liquid loss results in a concentration of the active ingredients in the solution, which must not exceed certain values. Liquid loss during storage determines, among other things, the shelf life of the product. The formulation of the multilayer film according to the invention is selected to achieve a very good water vapor barrier with good impact resistance.

[0115] The heat-sterilizable multilayer film according to the invention is characterized by the fact that it can be reliably welded using a thermally continuously heated welding process, even with port elements, requires no plasticizer, has minimal influence on medical solutions, and has a high water vapor barrier. At the same time, the multilayer film according to the invention exhibits significantly improved low-temperature impact strength, even at subzero temperatures. Multilayer films according to the invention provided with an additional functional layer (D), in particular a SiOx / PET functional layer, exhibit a significantly improved gas barrier, which also allows the storage of oxygen-sensitive ingredients.

[0116] The invention is explained in more detail below using examples, without limiting it. Example 1:

[0117] First polymer layer (A): 97 wt.% Moplen ®< HP525J from Lyondell Basell Corp., USA / polypropylene homopolymer 3 wt.% Tuftec ®< H1062 from Asahi Kasei, Japan / styrene-ethylene / butylene block copolymer

[0118] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0119] Second polymer layer (B): 65 wt.% Bormed ®< TD109CF from Borealis, Austria / polypropylene terpolymer 15 wt.% Tuftec ®< H1062 from Asahi Kasei, Japan / styrene-ethylene / butylene block copolymer 20 wt.% Bormed ®< SC 820 CF-11 from Borealis, Austria / heterophasic propylene copolymer

[0120] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0121] Middle polymer layer (C): 55 wt.% Bormed ®< SC 820 CF-11 from Borealis, Austria / heterophasic propylene copolymer 25 wt.% Tuftec ®< H1062 from Asahi Kasei, Japan / styrene-ethylene / butylene block copolymer 20 wt.% Engage ®< 8003 from Dow Chemical Company, USA / ethylene-octene polyolefin elastomer

[0122] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0123] The melts from the granulated compounds of the first polymer layer (A), the middle polymer layer (C) and the second polymer layer (B) were coextruded using process parameters typical for polypropylene (temperature 180 to 230°C) on a blown film line with water cooling and a multilayer film in the form of a film tube, the interior of which was flooded with sterile filtered air, was obtained.

[0124] The film was manufactured with a total thickness of 200 µm, with the first polymer layer (A) and second polymer layer (B) each having a thickness of 15 µm and the middle polymer layer (C) having a thickness of 170 µm.

[0125] The produced film can be sterilized with hot steam and can be firmly welded with welding tools heated to 125°C. Example 2:

[0126] A film tube produced according to Example 1 was additionally provided on both sides with a functional layer (D) made of SiOx / PET (Techbarrier T from Mitsubishi) in a layer thickness of 15 µm each.

[0127] First, a two-component adhesive (Dow ADCOTE 811A + ADCOTE 811B coreactant, as well as Dow Catalyst 9L10, available from Dow Chemical) was applied and then the film tube coated with the adhesive was laminated on both sides with the functional layer.

[0128] The film produced can be sterilized with hot steam and can be firmly welded using welding tools heated to 125°C. Example 3 (not according to the invention):

[0129] First polymer layer (A): 97 wt.% Moplen ®< HP525J from Lyondel IBasell Corp., USA / Polypropylene homopolymer 3 wt.% Tuftec ®< H1062 from Asahi Kasei, Japan / Styrene-ethylene / butylene block copolymer

[0130] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0131] Second polymer layer (B): 70 wt% Bormed ®< TD109CF from Borealis, Austria / polypropylene terpolymer 15 wt% Tuftec ®< H1062 from Asahi Kasei, Japan / styrene-ethylene / butylene block copolymer 15 wt% Bormed ®< RD804 CF-11, Borealis, Austria / random propylene copolymer

[0132] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0133] Middle polymer layer (C): 55 wt% Bormed ®< TD109CF from Borealis, Austria / polypropylene terpolymer 10 wt% Bormed ®< SC 820 CF-11 from Borealis, Austria / heterophasic propylene copolymer 20 wt% Tuftec ®< H1062 from Asahi Kasei, Japan / styrene-ethylene / butylene block copolymer 15 wt% Engage ®< 8003 from Dow Chemical Company, USA / ethylene-octene polyolefin elastomer

[0134] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0135] The melts from the granulated compounds of the first polymer layer (A), the middle polymer layer (C) and the second polymer layer (B) were coextruded using process parameters typical for polypropylene (temperature 180 to 230°C) on a blown film line with water cooling and a multilayer film in the form of a film tube, the interior of which was flooded with sterile filtered air, was obtained.

[0136] The film was manufactured with a total thickness of 200 µm, with the first polymer layer (A) and second polymer layer (B) each having a thickness of 15 µm, and the middle polymer layer (C) having a thickness of 170 µm. The produced film is steam sterilizable and can be firmly welded using welding tools heated to 125°C.

[0137] Example 4 (Comparative example (according to DE 10361851 A1, Example 1)): First polymer layer (A): 97 wt.% Moplen ®< HP525J from LyondellBasell Corp., USA / polypropylene homopolymer 3 wt.% Tuftec ®< H1062 from Asahi Kasei, Japan / styrene-ethylene / butylene block copolymer

[0138] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0139] Second polymer layer (B): 85 wt.% Bormed ®< TD109CF from Borealis, Austria / Polypropylene terpolymer 15 wt.% Tuftec ®< H1062 from Asahi Kasei, Japan / Styrene-ethylene / butylene block copolymer

[0140] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0141] Middle polymer layer (C): 75 wt% Bormed ®< TD109CF from Borealis, Austria / Polypropylene terpolymer 20 wt% Tuftec ®< H1062 from Asahi Kasei, Japan / Styrene-ethylene / butylene block copolymer 5 wt% Engage ®< 8003, Dow Chemical Company, USA / Ethylene-octene polyolefin elastomer

[0142] The formulation mentioned was mixed in a separate compounding step in the melt state and granulated for further use.

[0143] The film was coextruded using process parameters typical for polypropylene on a blown film line with water cooling.

[0144] The film was manufactured with a total thickness of 200 µm, with the first polymer layer (A) and second polymer layer (B) each having a thickness of 15 µm, and the middle polymer layer (C) having a thickness of 170 µm. The produced film is steam sterilizable and can be firmly welded using welding tools heated to 125°C.

[0145] To check the impact strength of the resulting films, a drop test is carried out according to DIN EN ISO 15747:2019-07. Description:

[0146] Production of infusion (IV) bags of the desired size, e.g., 1000 ml. IV bags are filled with water and tightly sealed (e.g., with a stopper). IV bags are steam sterilized at 121°C and must cool completely. Ten bags are stored at 20°C, 4°C, and -18°C for 24 hours each. The bags are then dropped onto the floor from the appropriate height (DIN EN ISO 15747:2019-07, Table A.1). A 1000 ml bag is stored at a height of 0.75 m (device) and then dropped onto the floor.

[0147] The test results for a bag with a capacity of 1000 ml (contents: water) are shown in Table 1. Multilayer film Head [m] Failure rate* Storage at 20°C Failure rate* Storage at 4°C Failure rate* Storage at -18°C Result Example 1 0,75 0 / 10 0 / 10 0 / 10 passed Example 2 0,75 0 / 10 0 / 10 0 / 10 passed Example 3 (not according to the invention) 0,75 0 / 10 2 / 10 7 / 10 failed Example 4 (Comparison) 0,75 0 / 10 7 / 10 10 / 10 failed Failure rate*: defective bags / number of tested bags

[0148] The drop test results show a direct correlation between the weight fraction of the impact modifier in the middle layer and the cold impact strength at subzero temperatures. Only the multilayer films of Examples 1 and 2 pass the drop test at temperatures of 4°C and -18°C due to the inventive composition (specific impact modifiers in all layers (A), (B), and (C) in specific amounts).

Claims

1. Heat-sterilizable multilayer film comprising a) a first polymer layer (A) containing at least one polypropylene homopolymer modified with at least one impact modifier; b) a second polymer layer (B) containing: B1) 51% to 68% by weight - based on (B) - of at least one polypropylene terpolymer; B2) 12% to 22% by weight - based on (B) - of at least one styrene block copolymer (SBC) elastomer; B3) 15% to 35% by weight - based on (B) - of at least one propylene-ethylene (block) copolymer, in which - based on (B3) - the proportion of the structural units of ethylene is ≥ 9% by weight, in many cases 9% to 15% by weight; and c) a central polymer layer (C) situated between the first polymer layer (A) and the second polymer layer (B), containing: C1) 20% to 30% by weight - based on (C) - of at least one styrene block copolymer (SBC) elastomer; C2) 15% to 30% by weight - based on (C) - of at least one polyethylene elastomer which is a copolymer of ethylene with an alpha-olefin containing 4 to 12 carbon atoms; C3) 40% to 65% by weight - based on (C) - of at least one propylene-ethylene (block) copolymer, in which - based on (C3) - the proportion of the structural units of ethylene is ≥ 9% by weight, in many cases 9% to 15% by weight.

2. Heat-sterilizable multilayer film as claimed in claim 1, in which the second polymer layer (B) contains: B1) 55% to 67% by weight, preferably 56% to 66% by weight; B2) 13% to 21% by weight, preferably 14% to 20% by weight; B3) 17% to 32% by weight, preferably 18% to 30% by weight.

3. Heat-sterilizable multilayer film as claimed in claim 1 or 2, in which component B1) is a terpolymer of propylene, ethylene and a C4-C12 α-olefin, preferably a terpolymer of propylene, ethylene and butylene.

4. Heat-sterilizable multilayer film as claimed in any of claims 1 to 3, in which the styrene block copolymer (SBC) elastomer B2) and / or C1) is selected from the group consisting of: styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-isoprene-styrene block copolymer (SIS) and styrene-butadienestyrene block copolymer (SBS), and particularly preferably SEBS and SEPS, in particular SEBS.

5. Heat-sterilizable multilayer film as claimed in any of claims 1 to 4, in which the central polymer layer (C) contains: C1) 21% to 30% by weight, preferably 22% to 27% by weight; C2) 15% to 25% by weight, preferably 17% to 23% by weight; C3) 45% to 65% by weight, preferably 50% to 60% by weight.

6. Heat-sterilizable multilayer film as claimed in any of claims 1 to 5, in which the polyethylene elastomer C2) is an ethylene-butylene copolymer and / or an ethylene-octene copolymer, in particular an ethylene-octene copolymer.

7. Heat-sterilizable multilayer film as claimed in any of claims 1 to 6, in which the propylene-ethylene copolymer B3) and / or C3) is a propylene-ethylene block copolymer.

8. Heat-sterilizable multilayer film as claimed in any of claims 1 to 7, in which the first polymer layer (A) contains 90% to 98% by weight, in particular 95% to 97% by weight, of a polypropylene homopolymer and 2% to 10% by weight, in particular 3% to 5% by weight, of at least one, preferably one, impact modifier selected from styrene block copolymers and / or copolymers of ethylene with at least one alpha-olefin containing 4 to 12, preferably 4 to 8, carbon atoms.

9. Heat-sterilizable multilayer film as claimed in any of claims 1 to 8, characterized in that the multilayer film consists of the polymer layers (A), (B) and (C), and the total film thickness of the multilayer film is 50 to 500 µm, preferably 100 to 400 µm, and - based in each case on the total film thickness of the multilayer film - the layer thickness of the first polymer layer (A) is 5% to 15% by weight, preferably 7% to 13% by weight, the layer thickness of the second polymer layer (B) is 5% to 15% by weight, preferably 7% to 13% by weight; and the layer thickness of the central polymer layer (C) is 70% to 85% by weight, preferably 74% to 80% by weight.

10. Method for producing a heat-sterilizable multilayer film as claimed in any of claims 1 to 9, wherein the first polymer layer (A), the central polymer layer (C) and the second polymer layer (B) are coextruded.

11. Heat-sterilizable multilayer film as claimed in any of claims 1 to 9, which comprises an additional functional layer (D) adjacent to the first polymer layer (A) on the outer side of (A) and wherein functional layer (D) contains at least one material selected from the group consisting of: ethylene-vinyl alcohol copolymers, polyvinyl alcohols, polyamides, liquid crystal polymers (LCP), aromatic polyesters, preferably terephthalic acid polyesters, particularly preferably polyethylene terephthalates (PET), silicon oxide (SiOx), aluminum oxide (AlOx) and acrylate-based polymers.

12. Heat-sterilizable multilayer film as claimed in claim 11, in which functional layer (D) consists of PET / SiOx.

13. Method for producing a laminated multilayer film sleeve made of a heat-sterilizable multilayer film as claimed in either of claims 11 and 12, comprising the following steps: (a') producing a film sleeve made of a multilayer film produced according to claim 10 by a blown film method, wherein the interior of the film sleeve is flooded with - preferably sterile-filtered - air; (b') optionally cooling the film sleeve produced in method step (a'); (c') coating the optionally cooled film sleeve with a pressure-sensitive adhesive layer on at least one side (first polymer layer (A)) of the film sleeve; (d') optionally drying the film sleeve provided with the pressure-sensitive adhesive layer; (e') laminating the at least one side (first polymer layer (A)) of the film sleeve coated with the pressure-sensitive adhesive layer with a functional layer (D), in particular a SiOx / PET functional layer; (f) optionally drying and curing the laminated film sleeve.

14. Use of a heat-sterilizable multilayer film as claimed in any of claims 1 to 9, 11 or 12 for production of a medical package, preferably a medical bag.

15. Method for producing a medical package, preferably a bag, made of a heat-sterilizable multilayer film as claimed in claims 1 to 9, 11 or 12, comprising the steps of: a) providing at least one multilayer film produced according to claim 10 or 13; b) optionally providing one or more port elements and / or flexible tubes; c) shaping a medical package, preferably a bag, from the at least one multilayer film, such that the second polymer layer (B) forms the inner face of the medical package, preferably the bag, and the first polymer layer (A) forms the outer face of the medical package, preferably the bag; d) optionally positioning the port elements and / or flexible tubes between the inner faces at the contours of the medical package, preferably the bag; e) contacting the inner faces at the contours of the medical package, preferably the bag, with one another and with port elements and / or flexible tubes optionally positioned in between; f) heat-sealing the inner faces at the contours of the medical package, preferably the bag, with one another and with port elements and / or flexible tubes optionally positioned in between.