Flexible multilayer films with high low temperature impact strength for medical packaging

Abstract

1. A heat sterilizable multilayer film having high low temperature impact strength for use in medical packaging, comprising: (a) a first polymer layer (A) containing a polypropylene homopolymer modified with an impact modifier; (b) a second polymer layer (B) containing: B1) 51% to 68% by weight of a polypropylene terpolymer; B2) 12% to 22% by weight of a styrene block copolymer elastomer; B3) 15% to 35% by weight of a propylene-ethylene copolymer; and c) an intermediate polymer layer (C) containing: C1) 20% to 30% by weight of a styrene block copolymer elastomer; C2) 15% to 30% by weight of a polyethylene elastomer; and C3) 40% to 65% by weight of a propylene-ethylene copolymer.

Description

[Technical field]

[0001] The present invention relates to a heat sterilizable multilayer film based on aliphatic polyolefins having particularly good impact strength at relatively low temperatures, to a process for producing said film, and to the use of said film for medical packaging. [Background technology]

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

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

[0004] Said bag must not only have the ability to collapse, ensuring complete emptying of the bag, but must also exhibit further performance criteria such as transparency, the ability to undergo hot steam sterilization at 121° C., sufficient mechanical strength under dynamic load, especially in the area of ​​the welded seam, good barrier properties against water vapor, load-bearing against standard cuff pressure applications, e.g. pressure injection, and from a pharmaceutical point of view, minimal impact of the package on the contents of the bag. Multilayer films with a polyolefin-based layer structure have been found to be advantageous with regard to the aforementioned properties.

[0005] Patent Document 1 describes a composite material comprising: a) a first outer layer containing polyurethane (PU); b) a second outer layer (inner surface of the bag, sealing layer), preferably consisting of a blend of PP homopolymer or copolymer and elastomer; and c) A multilayer film for medical applications such as medical bags is described, containing a polymer adhesion promoter, preferably an intermediate layer composed of an ethylene / α-olefin copolymer. Preferably, the second outer layer used is a blend of a propylene / ethylene copolymer (80%) and a SEBS block copolymer (20%).

[0006] Patent Document 2 describes a) a first layer (the inner surface of the bag, the sealing layer) composed of a blend of a PP homopolymer or copolymer and an elastomer; A five-layer multilayer film for medical applications such as medical bags is described, which contains: b) a second (middle) layer adjacent to a) and comprised of an ethylene / alpha-olefin copolymer; c) a third (middle) layer (ethylene / alpha-olefin copolymer) adjacent to b); d) a fourth adhesion promoting layer (an anhydride modified copolymer) adjacent to c); and e) a fifth layer (outer layer) comprised of a polyamide or copolyester.

[0007] Patent Document 3 discloses a heat sterilizable multilayer film for producing medical bags, which contains an outer layer (2), a support layer (4), and a flexible intermediate layer (3) with or without a heat seal layer (5), all layers containing polyolefin homopolymers and / or polyolefin copolymers (softening temperatures: (2) and (4) >121°C, (3) <70°C). An example four-layer film is made of (2) and (4) PP homopolymers, (3) PE or PP copolymer, and (5) PP copolymer.

[0008] Patent Document 4 describes a multilayer film for medical containers, preferably a three-layer multilayer film, which contains: (a) a first (=inner) heat-sealable layer consisting of a mixture of (i) polypropylene, (ii) an ethylene copolymer, and (iii) a further ethylene copolymer or modifier such as an elastomer (e.g., EPDM terpolymer, SBS, SEBS and SIS copolymer); (b) a second (middle) layer consisting of a mixture of (i) polyethylene (PE) (50% to 90% by weight) and (ii) a modifier; and (c) a third (outer) layer consisting of a mixture of (i) polypropylene and (ii) a modifier. It is preferable to use a modified PP copolymer for the outer layer.

[0009] Patent document 5 describes a flexible multilayer film for medical bags, in particular a three-layer multilayer film, which includes: (a) an (inner) sealant layer containing an (optionally modified) ethylene-propylene copolymer (ethylene content: 3.8% by weight); (b) an intermediate layer composed of a flexible polymer material (e.g., an elastomeric copolymer or terpolymer such as EPDM); and (c) an outer layer containing an ethylene-propylene copolymer.

[0010] Patent Documents 6 and 7 describe heat sterilizable three-layered multilayer films for producing medical bags, the outer layer of which consists of polypropylene homopolymer modified with an impact modifier (in the example at least 70% by weight, 97% by weight), the middle layer of which consists of polypropylene terpolymer modified with an impact modifier, and the (sealable) inner layer of which consists of polypropylene terpolymer and / or polypropylene copolymer modified with an impact modifier. Suitable impact modifiers are styrene-ethylene / butylene (SEBS) block copolymers, styrene-ethylene / propylene (SEPS) block copolymers, or ethylene / α-olefin copolymers. The middle layer can contain 20% to 80% by weight of PP terpolymer, 0% to 40% by weight of polyethylene copolymer, 0% to 60% by weight of SEB block copolymer or SEP block copolymer. The example films have a middle layer composed of 75 wt% PP terpolymer, 20 wt% SEBS block copolymer, and 5 wt% PE plastomer (ethylene / octene copolymer) and an inner layer composed of 85 wt% or 75 wt% PP terpolymer, 15 wt% or 20 wt% SEB block copolymer, and 0 wt% or 5 wt% PE plastomer.

[0011] Patent Document 8 describes a heat sterilizable three-layer multilayer film produced by coextrusion for use in medical bags. The example film has an outer layer composed of 97% by weight of polypropylene homopolymer and 3% by weight of SEBS block copolymer, a middle layer composed of 80% by weight of EXCELLEN, a heterophasic copolymer based on polypropylene and polyethylene, and 20% by weight of SEBS block copolymer, and an inner layer composed of 75% by weight of PP terpolymer, 20% by weight of SEBS block copolymer, and 5% by weight of PE plastomer.

[0012] Although known films have already achieved good results in terms of flexibility, ability to undergo heat sterilization and transparency, said films still have room for improvement, particularly in terms of impact strength, especially at relatively low temperatures, often between 4°C and -70°C, in particular between -18°C and -40°C, limiting their suitability for medical packaging stored in refrigerators or freezers.

[0013] Commercially available materials for deep-freezing applications are primarily packages (e.g. bags) made of pure polyethylene (e.g. for food) or polyvinyl chloride (e.g. for plasma). PE bags have very good low-temperature impact strength, but have the drawback of being unsuitable for heat sterilization at 121°C, which is required for medical films.

[0014] PVC-containing materials are considered to be harmful to health since they usually contain plasticizers that often leak out, and therefore attempts are being made to replace PVC with alternative materials, this is all the more true in the case of medical packaging and packaging that is to be stored in refrigerators or freezers. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] U.S. Patent No. 5,681,627 [Patent Document 2] U.S. Patent No. 5,695,840 [Patent Document 3] U.S. Patent No. 5,783,269 [Patent Document 4] EP-A0229475 [Patent Document 5] EP-A0199871 [Patent Document 6] DE-A10361851 [Patent Document 7] WO2020 / 127227A1 [Patent Document 8] DE20320212A1 Summary of the Invention [Problem to be solved by the invention]

[0016] It is therefore an object of the present invention to provide a heat sterilizable multilayer film for medical packaging, which does not have the above-mentioned drawbacks and in particular requires good low-temperature impact strength. Furthermore, the multilayer film, or the packages produced therefrom, must maintain properties such as high transparency, the ability to undergo hot steam sterilization at 121° C., sufficient mechanical strength under dynamic load, in particular in the area of ​​the welded seams, good barrier properties against water vapor, load-bearing capacity against standard cuff pressure application, e.g. pressure injection, and ability of the bag to collapse.

[0017] It is a further object of the present invention to provide a method for producing a heat sterilizable multilayer film, in particular a method for producing a film sleeve based on a heat sterilizable multilayer film. [Means for solving the problem]

[0018] The present invention provides a heat sterilizable multilayer film, comprising: 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) comprising (consisting of): B1) 51% to 68% by weight of at least one polypropylene terpolymer based on (B); B2) 12% to 22% by weight of at least one styrene block copolymer (SBC) elastomer based on (B); B3) 15% to 35% by weight of at least one propylene-ethylene (block) copolymer based on (B), in which the proportion of ethylene structural units based on (B3) is 9% by weight or more, often 9% to 15% by weight, preferably 10% by weight or more; and c) an intermediate polymer layer (C) located between the first polymer layer (A) and the second polymer layer (B) and containing (consisting of): C1) 20% to 30% by weight of at least one styrene block copolymer (SBC) elastomer based on (C); C2) 15% to 30% by weight of at least one polyethylene elastomer based on (C), which is a copolymer of ethylene and an alpha-olefin containing from 4 to 12 carbon atoms; C3) There is provided a heat sterilizable multilayer film comprising (consisting of) 40% by weight to 65% by weight of at least one propylene-ethylene (block) copolymer based on (C), in which the proportion of ethylene structural units based on (C3) is 9% by weight or more, often 9% by weight to 15% by weight, and preferably 10% by weight or more.

[0019] The proportions expressed as percentages by weight in each case total 100% by weight.

[0020] In the context of the present invention, a structural unit of a monomer in a (co)polymer is to be understood to mean the structural unit which derives from the monomer incorporated by polymerization.

[0021] The term "heat sterilizable" means that the corresponding material can be subjected to sterilization at high temperatures, preferably steam sterilization. Sterilization refers to a method that removes live microorganisms from materials and articles. The state of materials and articles thereby achieved is called "sterile". In the case of steam sterilization of filled or unfilled medical packaging, sterilization is performed using high-temperature steam and is usually carried out in an autoclave. This involves heating the medical packaging in steam to 121 °C at a pressure of 2 bar for preferably 20 minutes. The air in the autoclave is completely replaced by steam.

[0022] The term "multilayer film" refers to thermoplastic materials in multiple coextruded polymer layers that are joined together to form a film in the form of a running web or sleeve.

[0023] The term "impact modifier" refers to polymeric materials, such as styrenic block copolymer elastomers, polyethylene elastomers, and polypropylene elastomers, which when blended in the molten state improve the impact strength of the polymer surrounding the impact modifier.

[0024] The term "impact strength" refers to the property of a material to withstand dynamic loads. The Izod impact strength of plastics can be measured under defined conditions according to standard DIN EN ISO180:2013-08. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] First Polymer Layer (A) The first polymer layer (A) of the multilayer film according to the invention is by definition the polymer layer which is located on the outside of the package when the film is processed into a package, preferably a bag, and therefore requires a high melting / softening temperature, preferably above 125°C, particularly preferably between 127°C and 150°C, very particularly preferably between 130°C and 145°C, since the polymer layer is in direct contact with the surface of the fuser when the film is further processed into the package.

[0026] The first polymer layer (A) contains at least one, preferably one, polypropylene homopolymer modified with at least one, preferably one, impact modifier.

[0027] Preferably, the first polymer layer (A) consists of at least one, preferably one, polypropylene homopolymer modified with at least one, preferably one, impact modifier.

[0028] More preferably, the first polymer layer (A) contains a polypropylene homopolymer modified with an impact modifier.

[0029] The first polymer layer (A) contains (or consists of) at least one, preferably one, polypropylene homopolymer modified with generally 1% to 30% by weight, preferably 2% to 20% by weight, particularly preferably 2% to 10% by weight, in particular 3% to 5% by weight of at least one impact modifier to improve its (low temperature) impact strength.

[0030] The production of polypropylene homopolymer is known, and polypropylene homopolymer is commercially available, for example, from Lyondell Basell Corporation, USA.

[0031] Preferably, the first polymer layer (A) comprises (or consists of) a polypropylene homopolymer 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 copolymers (SEPS), styrene-isoprene-styrene block copolymers (SIS) and styrene-butadiene-styrene block copolymers (SBS), preferably SEBS and SEPS, in particular SEBS, and / or from the group of copolymers of ethylene and at least one alpha-olefin containing from 4 to 16, preferably from 4 to 12, particularly preferably from 4 to 8 carbon atoms, such as ethylene-butylene copolymers and / or ethylene-octene copolymers ethylene.

[0032] Particularly preferably, 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 a styrene block copolymer and / or a copolymer of ethylene and at least one alpha-olefin containing from 4 to 12, preferably from 4 to 8, carbon atoms.

[0033] In a preferred embodiment, the first polymer layer (A) contains (or consists of) 95% to 97% by weight of polypropylene homopolymer and 3% to 5% by weight of styrene-ethylene / butylene block copolymer.

[0034] The specified weights of the components of the first polymer layer (A) are based on the total weight of the first polymer layer (A).

[0035] Second Polymer Layer (B) The second polymer layer (B) is by definition the polymer layer located on the inside of the package when the multilayer film according to the invention is processed into a package, preferably a bag. Said polymer layer is responsible for the ability to tightly seal the package by heat sealing. The second polymer layer (B) of the film must be heat sealable to itself and to a properly inserted port element in a reliable manner, at the lowest possible temperature and with the shortest possible welding time, but heat sterilizable at temperatures above 121°C. A low welding temperature is particularly important to minimize structural stresses on the film structure. The melting / softening temperature of the second polymer layer (B) is therefore 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 / softening temperature of the first polymer layer (A).

[0036] The second polymer layer (B) of the multilayer film according to the invention has the following proportions (in each case 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% by weight to 35% by weight, preferably 17% by weight to 32% by weight, particularly preferably 18% by weight to 30% by weight It contains (or consists of) components B1), B2), and B3).

[0037] Component B1) Component B1) is at least one, preferably one, polypropylene terpolymer.

[0038] The term "terpolymer" refers to a copolymer made from three different monomers.

[0039] The term "polypropylene terpolymer" refers to a polypropylene molecular chain modified with two additional comonomers in the polymerization process. The preferred additional comonomers are ethylene and / or at least one C4-C 12 α-Olefins, preferably ethylene and C4-C 12 α-Olefins, particularly preferably ethylene and C4-C8 α-olefins, very particularly preferably ethylene and 1-butene.

[0040] Preferably, B1) is propylene, ethylene and C4-C 12 α-olefin terpolymers, in which the proportion of ethylene is preferably between 1% and 4% by weight, and C4-C 12 The proportion of α-olefins, preferably C4 to C8 α-olefins, in particular 1-butene, is preferably 9% to 12% by weight.

[0041] The proportions by weight are in each case based on the monomeric structural units which are incorporated into the terpolymer (B1) by polymerization.

[0042] Very particularly preferably, the polypropylene terpolymer (component B1)) is made up of structural units of propylene, ethylene and butylene.

[0043] The monomers are generally incorporated randomly into the polypropylene terpolymer (=component B1), ie the polypropylene terpolymer B1) is usually a random polypropylene terpolymer.

[0044] The polypropylene terpolymer B1) is modified with components B2) and B3) which act as impact modifiers in order to improve the impact strength, especially at low temperatures.

[0045] Component B2) Component B2) is at least one, preferably one, styrene block copolymer (SBC) elastomer.

[0046] The term "styrenic block copolymer elastomer" refers to synthetic thermoplastic elastomers based on styrenic block copolymers for the impact modification of polypropylene.

[0047] The at least one styrene block copolymer (SBC) elastomer B2) is preferably selected from the group consisting of styrene-ethylene-butylene-styrene block copolymers (SEBS), styrene-ethylene-propylene-styrene block copolymers (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymers (SEEPS), styrene-isoprene-styrene block copolymers (SIS) and styrene-butadiene-styrene block copolymers (SBS), and particularly preferably SEBS and SEPS, in particular SEBS.

[0048] It is also possible to partially replace the styrene block copolymer (SBC) elastomers with one or more thermoplastic olefin-based elastomers (TPE-O) (proportion of TPE-O: up to 45% by weight, preferably 20% to 30% by weight).

[0049] Preferably, component B2) is a styrenic block copolymer (SBC) elastomer that does not contain any proportion of olefin-based thermoplastic elastomers.

[0050] Ingredient B3) Component B3) is at least one, preferably one, propylene-ethylene (block) copolymer, in which the proportion of ethylene structural units based on (B3) is 9% by weight or more, often 9% by weight to 15% by weight, preferably 10% by weight or more, more preferably 10% by weight to 12% by weight.

[0051] Propylene-ethylene copolymers B3) are often also called "heterophasic" copolymers. In general, propylene-ethylene copolymers B3) are propylene-ethylene block copolymers having ethylene and propylene polymer blocks, thereby forming a heterogeneous phase (morphology).

[0052] Heterophasic propylene-ethylene (block) copolymers B3) differ both in their composition (proportion of ethylene structural units ≧9% by weight) and in their properties from propylene-ethylene copolymers in which the two monomers not used according to the invention as component B3) are randomly distributed and in which the proportion of ethylene structural units is generally not more than 8% by weight, often not more than 5% by weight. Such random propylene-ethylene copolymers usually form a homogeneous phase (morphology).

[0053] Preferably, the second polymer layer (B) according to the invention contains (or consists of) a polypropylene terpolymer made up of propylene, ethylene and butylene structural units (component B1), a styrene-ethylene-butylene-styrene block copolymer (SEBS) (component B2), and a propylene-ethylene (block) copolymer (component B3).

[0054] Particularly preferably, the second polymer layer (B) according to the invention comprises B1) a polypropylene terpolymer made up of 55% to 67% by weight, preferably 56% to 66% by weight, of structural units of propylene, ethylene and butylene; B2) 13% to 21% by weight, preferably 14% to 20% by weight, of styrene-ethylene-butylene-styrene block copolymer (SEBS); and B3) comprises (or consists of) 17% to 32% by weight, preferably 18% to 30% by weight, of a propylene-ethylene (block) copolymer (component B3).

[0055] The specified weights of components B1), B2) and B3) of the second polymer layer (B) are based on the total weight of the second polymer layer (B).

[0056] Intermediate polymer layer (C) The intermediate polymer layer (C) comprises the maximum mass proportion (at least 50% by weight) of the multilayer film, i.e. preferably 60% to 95% by weight, particularly preferably 70% to 90% by weight, very particularly preferably 75% to 85% by weight of the overall multilayer film, and is used to improve the impact strength of the overall structure.

[0057] The intermediate 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 (in each case based on (C)): C1) 20% by weight to 30% by weight, preferably 21% by weight to 30% by weight, particularly preferably 22% by weight to 27% by weight; C2) 15% by weight to 30% by weight, preferably 15% by weight to 25% by weight, particularly preferably 17% by weight to 23% by weight; C3) 40% to 65% by weight, preferably 45% to 65% by weight, particularly preferably 50% to 60% by weight, very particularly preferably 52% to 57% by weight.

[0058] Component C1) Component C1) is at least one, preferably one, styrene block copolymer (SBC) elastomer.

[0059] Since the styrene block copolymer (SBC) elastomer C1) is defined as component B2), reference is made to the relevant discussion regarding component B2).

[0060] Component C2) Component C2) is at least one, preferably one polyethylene elastomer which is a copolymer of ethylene and an alpha-olefin containing from 4 to 12, preferably from 4 to 8, carbon atoms.

[0061] The proportion of alpha-olefin structural units based on (C2) is preferably 20% by weight to 30% by weight.

[0062] Particularly preferably, the polyethylene elastomer C2) is an ethylene-butylene copolymer and / or an ethylene-1-octene copolymer, in particular an ethylene-1-octene copolymer.

[0063] component C3) Component C3) is at least one, preferably one, propylene-ethylene (block) copolymer, in which the proportion of ethylene structural units based on (C3) is 9% by weight or more, often 9% by weight to 15% by weight, preferably 10% by weight or more, more preferably 10% by weight to 12% by weight.

[0064] Since the propylene-ethylene (block) copolymer C3) is defined as component B3), reference is made to the relevant discussion regarding component B3).

[0065] Preferably, the intermediate polymer layer (C) according to the invention contains (or consists of) styrene-ethylene-butylene-styrene block copolymers (SEBS) (component C1)), ethylene-1-octene copolymers (component C2)), and propylene-ethylene (block) copolymers (component C3)).

[0066] Particularly preferably, the intermediate polymer layer (C) according to the invention is C1) 21% to 30% by weight, preferably 22% to 27% by weight, of styrene-ethylene-butylene-styrene block copolymer (SEBS); C2) 15% to 25% by weight, preferably 17% to 23% by weight, of an ethylene-octene copolymer; and C3) 45% by weight to 65% by weight, preferably 50% by weight to 60% by weight, of a propylene-ethylene (block) copolymer (component C3)) is contained (or consists of them).

[0067] The specified weights of components C1), C2) and C3) of the intermediate polymer layer (C) are based on the total weight of the intermediate polymer layer (C).

[0068] Functional layer (D) The heat sterilizable multilayer film according to the invention may further comprise an additional functional layer D) as an outer layer adjacent to the first polymer layer (A) on the outer side of (A), i.e. on the opposite side of (A) opposite the side comprising polymer layer (C).

[0069] The functional layer (D) preferably imparts airtight and / or waterproof properties to the heat sterilizable multilayer film and to packages made therefrom, such as medical bags or film sleeves.

[0070] The functional layer D) may be made of a material selected from the group consisting of ethylene-vinyl alcohol copolymers, polyvinyl alcohol, polyamides, liquid crystal polymers (LCPs), aromatic polyesters, preferably terephthalic polyesters, particularly preferably polyethylene terephthalate (PET), silicon oxide (SiO x ), aluminum oxide (AlO x ) and acrylate-based polymers.

[0071] Preferably, the functional layer (D) is made of PET / SiO x It consists of:

[0072] The functional layer (D) preferably has a layer thickness of 5 to 25 μm, in particular 10 to 20 μm.

[0073] PET / SiO xThe functional layer (D) consisting of significantly improves the gas barrier (eg oxygen barrier) of the heat sterilizable multilayer film according to the invention, so that the film is also very suitable for the storage of oxygen-sensitive ingredients.

[0074] SiO x / PET functional layer (D) reduces the oxygen barrier or oxygen transmission rate (OTR) of the heat sterilizable multilayer film according to the invention by a factor of 1000 according to ASTM F1927 (23°C, 50% RH) and has an OTR value of <1cm 3 / (m 2 × days) can be lowered to ASTM.

[0075] Multilayer Film Preferably, the heat sterilizable multilayer film of the present invention consists of polymer layers (A), (B) and (C).

[0076] In each of the polymer layers (A), (B) and (C), the multilayer film can contain conventional additives and / or processing aids in conventional amounts suitable for the intended use of the multilayer film.

[0077] Preferred additives are antioxidants and heat stabilizers (phosphitic and phenolic stabilizers such as Irgafos® 168, Irgafos P-EPQ, Irganox® 1076 or Irganox 1010), as well as acid scavengers, e.g. DHT-4A®, synthetic hydrotalcite (SHT) and magnesium oxide (MgO).

[0078] Preferably, the heat sterilizable multilayer film composed of polymer layers (A), (B) and (C) according to the present invention contains at least one antioxidant, one heat stabilizer and / or one acid scavenger, preferably in a total amount of <3000 ppm, based on the entire multilayer film.

[0079] Preferably, the polymer layers (A), (B) and (C) are adhered to each other without the use of adhesion promoters, i.e. the multilayer film according to the invention, which is composed of the polymer layers (A), (B) and (C), preferably does not contain adhesion promoters. Furthermore, preferably, at least the second polymer layer (B) does not contain further additives and / or processing aids (e.g. modifiers or plasticizers such as mineral oils), and very particularly preferably, none of the polymer layers (A), (B) and (C) contains further additives and / or processing aids in addition to the additives mentioned above as preferred. Thus, during sterilization and storage, the medicine or medicinal solution is not or only little affected by the multilayer film according to the invention as a packaging material.

[0080] In the case of a multilayer film according to the invention consisting of polymer layers (A), (B), (C) and a functional layer (D), the multilayer film generally contains, in addition to the additives mentioned above, as a preference, an adhesion promoter or a pressure-sensitive adhesive.

[0081] The layer thickness of the first polymer layer (A) is generally from 5 to 15% by weight, preferably from 7 to 13% by weight, particularly preferably from 7.5 to 10% by weight, of the total film thickness of the multilayer film according to the present invention.

[0082] The layer thickness of the second polymer layer (B) is generally from 5 to 15% by weight, preferably from 7 to 13% by weight, particularly preferably from 7.5 to 10% by weight, of the total film thickness of the multilayer film according to the present invention.

[0083] The intermediate polymer layer (C) comprises the largest proportion of the multilayer film according to the invention (preferably at least 70% by weight of the total film thickness) and is used to improve the impact strength of the overall structure.

[0084] In a multilayer film consisting of (A), (B) and (C), the thickness of the intermediate polymer layer (C) is generally 70 to 85% by weight, preferably 74 to 80% by weight.

[0085] When the optional functional layer (D) is present, its layer thickness is preferably 2.5% by weight to 12.5% ​​by weight, particularly preferably 5% by weight to 10% by weight, of the total film thickness of the multilayer film according to the present invention.

[0086] The total film thickness of the multilayer film according to the invention is preferably 50 to 500 μm, particularly preferably 100 to 400 μm, very particularly preferably 150 to 300 μm.

[0087] The total film thickness of the 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.

[0088] The multilayer film is made up of polymer layers (A), (B) and (C), and the total film thickness of the multilayer film is 50 to 500 μm, particularly preferably 100 to 400 μm. In either case, based on the total film thickness of the multilayer film, The thickness of the first polymer layer (A) is 5% by weight to 15% by weight, preferably 7% by weight to 13% by weight; The layer thickness of the second polymer layer (B) is 5% by weight to 15% by weight, preferably 7% by weight to 13% by weight; The thickness of the intermediate polymer layer (C) is 70% by weight to 85% by weight, preferably 74% by weight to 80% by weight; Particular preference is given to multilayer films according to the invention, characterized in that the proportions of (A), (B) and (C) in each case total 100% by weight.

[0089] Method for producing multilayer films The present invention further provides a method for producing a multilayer film according to the present invention, wherein the first polymer layer (A), the intermediate polymer layer (C) and the second polymer layer (B) are coextruded.

[0090] Coextrusion involves combining plastic melts of polymer layers (A), (B) and (C) before they exit an extruder profile die to form a multilayer film according to the present invention.

[0091] In most cases, the extrusion process is a two-stage process. In the first step, the materials used for the individual polymer layers are mixed and compressed in an extruder, preferably a parallel twin-screw extruder (compounder), a heated / cooled mixer or a pellet press. Then, the plastic melts of the polymer layers (A), (B) and (C) are brought together in another extruder to either directly combine them or to separate them in space and time before they exit the profile die to form the multilayer film according to the invention.

[0092] Preferably, the multilayer film obtained by the method according to the invention is shock-cooled with water.

[0093] By coextrusion, the multilayer film according to the invention can be obtained in the form of a flat film (for example when using a slot die, the flat film method) or a film sleeve (blowing film method, for example by filling the interior of the film sleeve with preferably sterile filtered air), the outer side consisting of a first polymer layer (A) and the inner side consisting of a second polymer layer (B).

[0094] In a further process step, an optional functional layer (D) can be applied to the multilayer film obtained by the process according to the invention, for example by hot lamination or preferably by lamination.

[0095] According to a particular embodiment for producing a multi-layer laminate film sleeve according to the invention, the method according to the invention comprises the following steps: (a') producing a film sleeve made of the multilayer film according to the invention by a blown film process, the interior of which is preferably filled with sterile filtered air; (b') optionally cooling the film sleeve produced in process 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 with the pressure sensitive adhesive layer applied thereto; (e') laminating at least one side of the film sleeve coated with the pressure-sensitive adhesive layer (first polymer layer (A)) with a functional layer (D), in particular a SiOx / PET functional layer; (f) optionally drying and curing the laminated film sleeve. Includes.

[0096] According to the aforementioned embodiment of the method according to the invention, the two parallel inner surfaces of the film sleeve (=second polymer layer (B)) are preferably directly bonded to one another after melt extrusion or coextrusion of the film sleeve, thus making it possible to coat the outer surface of the film sleeve (first polymer layer (A)) while the interior of the film sleeve remains closed. The closed interior, which expands during the subsequent use of the resulting film sleeve, is therefore substantially free of particles.

[0097] Preferably, in the above-mentioned embodiment of the method according to the invention, the interior of the film sleeve is filled with sterile filtered air, thus maintaining a multi-layer laminated film sleeve that is low in particles and highly suitable, especially for medical purposes.

[0098] Particularly preferably, the low particle multi-layer laminate film sleeve is produced by carrying out the above-described method according to the present invention in a clean room.

[0099] In the above embodiment of the method according to the invention, it is preferred to use an adhesion promoter that can be fully cured after about 2 weeks, preferably 1 week, at room temperature. In a heating chamber, curing can also be achieved more quickly at higher temperatures, preferably above 30°C, often between 40°C and 60°C.

[0100] Suitable adhesion promoters (pressure-sensitive adhesives, adhesives or laminating adhesives) are, for example, isocyanates, polyurethanes, poly(ethyl acrylate / methacrylate esters), pure acrylate copolymers, vinyl ester / acrylate copolymers or inorganic-organic hybrid polymers.

[0101] Preferred adhesion promoters are two-part systems that can be solvent-based or solventless, and silane-based or silane-free, optionally with an additional "catalyst" that accelerates cure.

[0102] Suitable solvent-based two-component systems are, for example, polyurethane adhesives, - Dow ADCOTE™ 675A + ADCOTE™ 675C coreactant; - Dow ADCOTE 811A+ADCOTE 811B co-reactant; - Dow ADCOTE E735A-75+ADCOTE™ E735C2 coreactant: - MORCHEM PS241 AE+CS-97 coreactant, - Henkel Loctite Liofol LA2798+Henkel Loctite Liofol LA7371; - Henkel LOCTITE HY 4070 2K Hybrid Adhesive, including commercially available systems such as:

[0103] The above-described system can optionally be used with "catalysts," including commercially available catalysts such as Dow Catalyst 9L10 (a polyisocyanate), Dow Catalyst 9L200, and Dow Catalyst F Adcote40-3E.

[0104] Suitable solvent-free two-component systems are, for example, polyurethane adhesives, - Dow MOR-FREE™ L75-720 Adhesive - + CR88-720 or CR88-721 or MOR-FREE™ C79 S coreactant - Dow MOR-FREE™ 203A adhesive + MOR-FREE™ 200C co-reactant - Including commercially available systems such as Dow MOR-FREE™ L705 adhesive + MOR-FREE™ C79 or MOR-FREE™ C-102 coreactant.

[0105] Alternatively, the adhesion promoters used may be one-component systems, solvent-based or solvent-free, and silane-based or silane-free, optionally with an additional "catalyst" to accelerate cure.

[0106] Suitable solvent-free one-component systems are, for example, commercially available Dow MOR-FREE™ ELM415A (polyurethane adhesive) or SENOBOND® WB film lamination adhesive FP NDC375224.

[0107] Particularly preferably, the adhesive is selected so as to comply with the requirements of the pharmacopoeia limits, for example with regard to migration properties, and is preferably free of organic solvents.

[0108] Depending on the procedure or the desired coating, the adhesive layer can be applied to one or both sides of the film sleeve produced by coextrusion. This can be done, for example, by spraying or knife coating. The use of aqueous solutions of the relevant adhesives is also suitable.

[0109] After applying the adhesive layer, the resulting film sleeve can be optionally dried. For example, if the adhesive is applied using water, drying can be achieved by evaporating the water. The thickness of the pressure-sensitive adhesive layer is preferably in the range of 1 to 10 μm.

[0110] The present invention further provides the use of a multilayer film according to the invention for producing a medical package, preferably a medical bag.

[0111] The present invention also provides the use of a medical package according to the invention as a container for at least one medicament.

[0112] The medical package according to the invention is particularly suitable as a container for at least one medicine, and the multilayer film according to the invention, thanks to the specially modified polymer layer (C), is also particularly suitable for packaging and storing medicinal solutions at sub-zero temperatures.

[0113] In a preferred embodiment, the package according to the invention is divided into chambers, so that it can be used as a container for multiple medicaments at the same time. This is relevant, for example, for combinations of medicaments that need to be administered together but are not stable in combination over a long period of time, or for solid medicaments that are administered in the form of a solution or suspension but are not stable in solution or suspension for long periods of time. The components of the final dosage form can be stored separately using separate chambers and mixed together by opening the separation point just before administration.

[0114] The method for producing a medical package, preferably a bag, according to the present invention comprises the steps of: a) providing at least one heat sterilizable multilayer film according to the present invention; b) optionally providing one or more port elements and / or flexible 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 an inner surface of the medical package, preferably a bag, and the first polymer layer (A) forms an outer surface of the medical package, preferably a bag; d) optionally disposing a port element and / or flexible tubing between the contoured inner surfaces of the medical package, preferably a bag; e) contacting the inner surfaces with each other and with a port element and / or flexible tube optionally disposed between the contours of the medical package, preferably the bag; f) heat sealing the inner surfaces to each other and to the port elements and / or flexible tubing optionally disposed between the contours of the medical package, preferably the bag. Includes.

[0115] 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 shape of the film provided, the remaining part of the method may differ in specific details. The obtained low-particle film sleeve can be laminated with a functional layer (D), for example a SiOx / PET functional layer, by an additional method step.

[0116] Depending on the use of the medical package, preferably the bag, according to the invention, after the multilayer film according to the invention is provided, additional elements, such as port elements and / or flexible tubes, can be optionally applied in step b). Providing these elements is useful, for example, when the medical package, preferably the bag, according to the invention is used as a fixed component of a medical device or is connected to a medical device. Omission of step b) can be useful, for example, when the medical package, preferably the bag, is used only for storing medicines and is damaged, for example by tearing open or puncturing with a cannula, in order to remove the medicines.

[0117] In step c), the multilayer film provided according to the invention is put into the form of a medical package, preferably a bag. If a tubular film is provided in step a), 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, so that the shaping of the medical package, preferably the bag, can for example only involve cutting the tubular film to the desired length. If a flat film is provided in step a), the medical package, preferably the bag, can for example be shaped in step c) by cutting said portion into a mirror symmetrical shape from one multilayer film, folding it along a mirror axis with the ends of the film coinciding with each other, with the second polymer layer (B) on the inside. Alternatively, the medical package, preferably the bag according to the invention can for example be shaped from two flat films, by cutting the two pieces into a mirror symmetrical shape from each other, and overlapping them coinciding with each other, with the second polymer layer (B) on the inside. A rectangular shape is particularly preferred for cutting, since it results in the least loss of material and is the simplest to process. However, other shapes are possible, for example it is possible to manufacture the medical package, preferably a bag, with an aesthetic shape that is attractive to children and distracts from the actual administration of the medicine.

[0118] Depending on whether additional elements such as port elements and / or flexible tubes have been provided in step b), said elements can be placed in step d) between the inner contour surfaces of the formed medical package, preferably the bag. In the case of a tubular film, this means the insertion of the additional element into the opening of the tubular film. Here, the element can be placed only on two opposite sides of the medical package, preferably the bag. In the case of a flat film, this means the insertion of the additional element between the ends of one or more pieces of flat film superimposed in step c) so that they coincide with each other. Here, the element can be placed at any point along the ends, most preferably at two opposite ends.

[0119] In step e), the inner surfaces of the shaped medical package, preferably a bag, come into contact with each other and optionally with additional elements located between the inner surfaces of the contours of the bag, so that in step f), the inner surfaces can be sealed to each other by applying heat and optionally mechanical pressure. In the case of heat sealing, the temperature is preferably selected to be higher than the melting / softening point of the second polymer layer (B) but lower than the melting / softening point of the first polymer layer (A). This ensures that the second polymer layer (B) melts at the contour of the medical package, preferably a bag, thereby allowing it to close permanently and liquid-tight, while the first polymer layer (A) retains its shape, thereby maintaining the stability of the medical package, preferably a bag.

[0120] An important criterion for using the multilayer film according to the present invention as a primary packaging material for pharmaceutical solutions is the barrier effect against liquid loss, which leads to the concentration of the active ingredient in the solution and must not exceed a certain value. The liquid loss during storage determines, among other things, the shelf life of the product. The formulation of the multilayer film according to the present invention is selected so that a very good water vapor barrier is achieved together with good impact strength.

[0121] The heat sterilizable multilayer film of the invention is distinguished by the fact that it can be reliably heat-sealed even with port elements by a continuous heat sealing method, does not require plasticizers, has little effect on drug solutions and has a high barrier against water vapor. At the same time, the multilayer film according to the invention exhibits a significantly improved impact strength at low temperatures, even at temperatures below freezing. The multilayer film according to the invention with an additional functional layer (D), in particular a SiOx / PET functional layer, has a significantly improved gas barrier, which also allows the preservation of oxygen-sensitive ingredients.

[0122] The present invention will be explained in more detail based on the following examples, but is not limited thereto. EXAMPLES

[0123] First polymer layer (A): - 97% by weight Moplen® HP525J / polypropylene homopolymer from Lyondell Basell Corp., USA - 3% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation

[0124] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0125] Second polymer layer (B): - 65% by weight of Bormed® TD109CF / polypropylene terpolymer from Borealis, Austria - 15% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation - 20% by weight of Bormed® SC820CF-11 / heterophasic propylene copolymer from Borealis, Austria

[0126] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0127] Middle polymer layer (C): - 55% by weight of Bormed® SC820 CF-11 / heterophasic propylene copolymer from Borealis, Austria - 25% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation - 20% by weight of Engage® 8003 / ethylene-octylene diolefin elastomer from Dow Chemical Company, USA

[0128] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0129] The melt from the granulation compound of the first polymer layer (A), the middle polymer layer (C) and the second polymer layer (B) was coextruded in a blown film line equipped with water cooling using process parameters usual for polypropylene (temperature 180 ° C - 230 ° C). A multilayer film was obtained in the form of a film sleeve, the inside of which was filled with sterile filtered air.

[0130] The film was made with a total thickness of 200 μm, with the first polymer layer (A) and the second polymer layer (B) both having a thickness of 15 μm, and the intermediate polymer layer (C) having a thickness of 170 μm.

[0131] The films produced are hot steam sterilizable and permanently heat sealable using welding tools calibrated to a temperature of 125°C. EXAMPLES

[0132] The film sleeve produced according to Example 1 was further provided on both sides with a functional layer (D) consisting of SiOx / PET (Techbarrier T, Mitsubishi Chemical Corporation) with a layer thickness of 15 μm on each side.

[0133] First, a two-component adhesive (Dow ADCOTE 811A + ADCOTE 811B co-reactant, and Dow Catalyst 9L10, available from Dow Chemical) was applied to both sides of a film sleeve laid flat, and then a functional layer was laminated to both sides of the adhesive-coated film sleeve.

[0134] The films produced are sterilizable with hot steam and can already be permanently heat-sealed using welding tools adjusted to a temperature of 125°C. EXAMPLES

[0135] (Not according to the present invention) First polymer layer (A): - 97% by weight Moplen® HP525J / polypropylene homopolymer from Lyondell Basell Corp., USA - 3% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation

[0136] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0137] Second polymer layer (B): - 70% by weight of Bormed® TD109CF / polypropylene terpolymer from Borealis, Austria - 15% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation - 15% by weight of Bormed® RD804CF-11 / random propylene copolymer from Borealis, Austria

[0138] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0139] Middle polymer layer (C): - 55% by weight of Bormed® TD109CF / polypropylene terpolymer from Borealis, Austria - 10% by weight of Bormed® SC820CF-11 / heterophasic propylene copolymer from Borealis, Austria - 20% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation - 15% by weight of Engage® 8003 / ethylene-octylene diolefin elastomer from Dow Chemical Company, USA

[0140] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0141] The melt from the granulation compound of the first polymer layer (A), the intermediate polymer layer (C) and the second polymer layer (B) was coextruded (temperature 180°C-230°C) in a blown film line equipped with water cooling using process parameters conventional for polypropylene, and a multilayer film was obtained in the form of a film sleeve, the interior of which was filled with sterile filtered air.

[0142] The film was made with a total thickness of 200 μm, with the first polymer layer (A) and the second polymer layer (B) both having a thickness of 15 μm, and the middle polymer layer (C) having a thickness of 170 μm. The produced film is sterilizable with hot steam and permanently heat sealable using a welding tool adjusted to a temperature of 125° C. EXAMPLES

[0143] (Comparative Example (Based on Example 1 of Patent Document 6)): First polymer layer (A): - 97% by weight Moplen® HP525J / polypropylene homopolymer from Lyondell Basell Corp., USA - 3% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation

[0144] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0145] Second polymer layer (B): - 85% by weight of Bormed® TD109CF / polypropylene terpolymer from Borealis, Austria - 15% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation

[0146] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0147] Middle polymer layer (C): - 75% by weight of Bormed® TD109CF / polypropylene terpolymer from Borealis, Austria - 20% by weight of Tuftec® H1062 / styrene-ethylene / butylene block copolymer manufactured by Asahi Kasei Corporation - 5% by weight of Engage® 8003 / ethylene-octylene diolefin elastomer from Dow Chemical Company, USA

[0148] The described formulations were mixed in a molten state in a separate compounding step and granulated for further use.

[0149] The films were coextruded on a blown film line equipped with water cooling using process parameters typical for polypropylene.

[0150] The film was made with a total thickness of 200 μm, with the first polymer layer (A) and the second polymer layer (B) both having a thickness of 15 μm, and the middle polymer layer (C) having a thickness of 170 μm. The produced film is sterilizable with hot steam and permanently heat sealable using a welding tool adjusted to a temperature of 125° C.

[0151] The impact strength of the obtained films is checked by carrying out a drop test according to DIN EN ISO15747:2019-07.

[0152] explanation - Produce an intravenous (IV) bag of the desired size, e.g. 1000ml; - The IV bag was filled, e.g. with water, and tightly closed (e.g. with a stopper); - IV bags are sterilized with high temperature steam at 121°C and must be cooled completely. - 10 bags were stored at 20°C for 24 hours, 10 bags at 4°C for 24 hours, and 10 bags at -18°C for 24 hours. - The bag was then dropped from a suitable height to the floor (DIN EN ISO15747:2019-07, table A.1). A 1000 ml bag was stored at a height of 0.75 m (apparatus) and then dropped to the floor.

[0153] The test results for a 1000 ml bag (contents: water) are shown in Table 1.

[0154] [Table 1]

[0155] The drop test results show that there is a direct correlation between the weight percentage of the impact modifier in the intermediate layer and the low temperature impact strength below freezing. With the composition according to the present invention (specific impact modifier in specific amounts in all layers (A), (B) and (C)), only the multilayer films of Examples 1 and 2 passed the drop test at temperatures of 4°C and -18°C.

Claims

1. A heat sterilizable multilayer film, 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 of at least one polypropylene terpolymer based on (B); B2) 12% to 22% by weight of at least one styrene block copolymer (SBC) elastomer based on (B); B3) 15% to 35% by weight of at least one propylene-ethylene (block) copolymer based on (B), the proportion of ethylene structural units based on (B3) being 9% by weight or more, often 9% to 15% by weight; and c) an intermediate polymer layer (C) located between said first polymer layer (A) and said second polymer layer (B) and containing: C1) 20% to 30% by weight of at least one styrene block copolymer (SBC) elastomer based on (C); C2) 15% to 30% by weight of at least one polyethylene elastomer based on (C), which is a copolymer of ethylene and an alpha-olefin containing from 4 to 12 carbon atoms; C3) 40% to 65% by weight of at least one propylene-ethylene (block) copolymer based on (C), the proportion of ethylene structural units based on (C3) being 9% by weight or more, often between 9% and 15% by weight; 1. A heat sterilizable multilayer film comprising:

2. The second polymer layer (B) is B1) 55% to 67% by weight, preferably 56% to 66% by weight; B2) 13% to 21% by weight, preferably 14% to 20% by weight; 2. The heat sterilizable multilayer film of claim 1, comprising 17% to 32% by weight, preferably 18% to 30% by weight, of B3).

3. Component B1) is a copolymer of propylene, ethylene and C ４ ~C １２ 3. The heat sterilizable multilayer film according to claim 1, which is a terpolymer of an α-olefin, preferably a terpolymer of propylene, ethylene and butylene.

4. 4. The heat sterilizable multilayer film according to claim 1 , wherein the styrene block copolymer (SBC) elastomers B2) and / or C1) are selected from the group consisting of styrene-ethylene-butylene-styrene block copolymers (SEBS), styrene-ethylene-propylene-styrene block copolymers (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymers (SEEPS), styrene-isoprene-styrene block copolymers (SIS) and styrene-butadiene-styrene block copolymers (SBS), particularly preferably SEBS and SEPS, in particular SEBS.

5. The intermediate polymer layer (C) is C1) 21% to 30% by weight, preferably 22% to 27% by weight; C2) 15% to 25% by weight, preferably 17% to 23% by weight; The heat sterilizable multilayer film according to any one of claims 1 to 4, comprising 45 to 65% by weight, preferably 50 to 60% by weight, of C3).

6. The heat sterilizable multilayer film according to any one of claims 1 to 5, wherein the polyethylene elastomer C2) is an ethylene-butylene copolymer and / or an ethylene-octene copolymer, in particular an ethylene-octene copolymer.

7. The heat sterilizable multilayer film according to any one of claims 1 to 6, wherein the propylene ethylene copolymer B3) and / or C3) is a propylene ethylene block copolymer.

8. 8. The heat sterilizable multilayer film according to claim 1 , wherein the first polymer layer (A) contains 90% to 98% by weight, in particular 95% to 97% by weight of 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 and at least one alpha-olefin containing 4 to 12, preferably 4 to 8, carbon atoms.

9. The multilayer film is composed 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 in any case, based on the total film thickness of the multilayer film, The thickness of the first polymer layer (A) is 5% by weight to 15% by weight, preferably 7% by weight to 13% by weight; The layer thickness of the second polymer layer (B) is 5% by weight to 15% by weight, preferably 7% by weight to 13% by weight; 9. The heat sterilizable multilayer film according to claim 1, wherein the layer thickness of the intermediate polymer layer (C) is 70% to 85% by weight, preferably 74% to 80% by weight.

10. 10. The method for producing a multilayer film according to any one of claims 1 to 9, wherein the first polymer layer (A), the intermediate polymer layer (C) and the second polymer layer (B) are coextruded.

11. The additional functional layer (D) is adjacent to the first polymer layer (A) on the outside of (A), and the functional layer (D) is preferably made of ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyamide, liquid crystal polymer (LCP), aromatic polyester, preferably terephthalic polyester, particularly preferably polyethylene terephthalate (PET), silicon oxide (SiO ｘ ), aluminum oxide (AlO ｘ 10. The heat sterilizable multilayer film of claim 1, comprising at least one material selected from the group consisting of: acrylate-based polymers; and acrylate-based polymers.

12. The functional layer (D) is a PET / SiO ｘ The heat sterilizable multilayer film according to claim 11,

13. 13. A method for manufacturing a multi-layer laminate film sleeve made of the multi-layer film of claim 11 or 12, comprising the steps of: (a') producing a film sleeve, the interior of which is preferably filled with sterile filtered air, made of the multilayer film produced according to claim 10 by a blown film process; (b') optionally cooling the film sleeve produced in process 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 with the pressure sensitive adhesive layer applied thereto; (e') laminating at least one side of the film sleeve coated with the pressure sensitive adhesive layer (first polymer layer (A)) with a functional layer (D), in particular a SiOx / PET functional layer; (f) optionally drying and curing the laminated film sleeve.

14. Use of the multilayer film according to any one of claims 1 to 9, 11 and 12 for the manufacture of medical packages, preferably medical bags.

15. A method for producing a medical package, preferably a bag, made of the multilayer film according to any one of claims 1 to 9, 11 and 12, comprising the steps of: a) providing at least one multilayer film made according to claim 10 or 13; b) optionally providing one or more port elements and / or flexible tubing; c) forming said medical package, preferably said bag, from said at least one multilayer film such that said second polymer layer (B) forms an inner surface of said medical package, preferably said bag, and said first polymer layer (A) forms an outer surface of said medical package, preferably said bag; d) optionally disposing said port element and / or flexible tube between the contoured inner surfaces of said medical package, preferably said bag; e) contacting said inner surfaces with each other and with a port element and / or flexible tube optionally disposed between the contours of said medical package, preferably said bag; f) heat sealing said inner surfaces to each other and to a port element and / or flexible tubing optionally disposed between the contours of said medical package, preferably said bag.