FLEXIBLE HEAT-STERILIZABLE NON-PVC MULTILAYER FILM FOR MEDICAL PACKAGINGS

Abstract

Flexible, heat-sterilizable multilayer film for medical packagings, comprising (a) a first polymer layer (A) containing impact-modified propylene homopolymer; (b) a second polymer layer (B) containing: B1) 60% to 85% by weight of a homogeneous composition (B1) having a melting point of >125? C. and a density of from 945 to 960 kg/m3, composed of: B11) 65% to 85% by weight of ethylene homopolymer, and B12) 15% to 35% by weight of ethylene/C4-C12 alpha-olefin copolymer; B2) 11% to 30% by weight of propylene terpolymer; B3) 4% to 15% by weight of polyethylene elastomer (ethylene/C4-C12 alpha-olefin copolymer); c) a middle polymer layer (C) containing: C1) 61% to 80% by weight of propylene terpolymer; C2) 15% to 25% by weight of styrene block copolymer elastomer; C3) 5% to 19% by weight of polyethylene elastomer.

Claims

1-19. (canceled)

20. A heat-sterilizable multilayer film comprising a) a first polymer layer (A) containing at least one propylene homopolymer modified with at least one impact modifier; b) a second polymer layer (B) containing: B1) 60% to 85% by weight, based on (B), of a homogeneous composition (B1) consisting of: B11) 65% to 85% by weight, based on (B1), of ethylene homopolymer, and B12) 15% to 35% by weight, based on (B1), of at least one ethylene copolymer which contains as comonomer at least one alpha-olefin having 4 to 12 carbon atoms, where (B1) has a melting temperature (determined by Differential Scanning calorimetry (DSC)) of >125? C. and a density (in accordance with DIN EN ISO 1183-1 (2019-09)Method B) of 945 to 960 kg/m.sup.3; B2) 11% to 30% by weight, based on (B), of at least one propylene terpolymer; and B3) 4% to 15% by weight, based on (B), of at least one polyethylene elastomer which is a copolymer of ethylene with at least one alpha-olefin having 4 to 12 carbon atoms; and c) a central polymer layer (C) situated between the first polymer layer (A) and the second polymer layer (B), containing: C1) 61% to 80% by weight, based on (C), of at least one propylene terpolymer; C2) 15% to 25% by weight, based on (C), of at least one styrene block copolymer elastomer; and C3) 5% to 19% by weight, based on (C), of at least one polyethylene elastomer which is a copolymer of ethylene with at least one alpha-olefin containing 4 to 12 carbon atoms.

21. The heat-sterilizable multilayer film of claim 20, wherein the homogeneous composition (B1) consists of: B11) 70% to 80% by weight, and B12) 20% to 30% by weight.

22. The heat-sterilizable multilayer film of claim 20, wherein the ethylene copolymer (B12) is prepared by copolymerization of ethylene and at least one alpha-olefin in the presence of a metallocene catalyst.

23. The heat-sterilizable multilayer film of claim 20, wherein the ethylene homopolymer (B11) used is a high-density polyethylene (HDPE).

24. The heat-sterilizable multilayer film of claim 20, wherein the ethylene copolymer (B12) contains 25% to 40% by weight of at least one alpha-olefin comonomer.

25. The heat-sterilizable multilayer film of claim 20, wherein the ethylene copolymer (B12) contains as comonomer at least one alpha-olefin selected from 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene.

26. The heat-sterilizable multilayer film of claim 20, wherein the component (B2) and/or (C1) is a terpolymer of propylene, ethylene, and/or C.sub.4 to C.sub.16 ?-olefins.

27. The heat-sterilizable multilayer film of claim 20, wherein the component (B3) is a copolymer of ethylene with an alpha-olefin having 7 to 12 carbon atoms.

28. The heat-sterilizable multilayer film of claim 20, wherein the second polymer layer (B) contains: B1) 65% to 80% by weight; B2) 15% to 25% by weight; and B3) 4% to 12% by weight.

29. The heat-sterilizable multilayer film of claim 20, wherein the central polymer layer (C) contains: C1) 65% to 75% by weight; C2) 17% to 22% by weight; and C3) 8% to 17% by weight.

30. The heat-sterilizable multilayer film of claim 20, wherein the styrene block copolymer (SBC) elastomer (C2) 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-butadiene-styrene block copolymer (SBS).

31. The heat-sterilizable multilayer film of claim 20, wherein the polyethylene elastomer (C3) is an ethylene-butylene copolymer and/or an ethylene-octene copolymer.

32. The heat-sterilizable multilayer film of claim 20, wherein the multilayer film consists of the polymer layers (A), (B), and (C), and the total film thickness of the multilayer film ranges from 50 to 500 ?m, 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; the layer thickness of the second polymer layer (B) is 5% to 15% by weight; and the layer thickness of the central polymer layer (C) is 70% to 90% by weight.

33. A method for producing the heat-sterilizable multilayer film of claim 20, wherein the first polymer layer (A), the central polymer layer (C), and the second polymer layer (B) are coextruded.

34. The heat-sterilizable multilayer film of claim 20, comprising an additional functional layer (D) adjacent to the first polymer layer (A) on the outer side of (A) and wherein the 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, silicon oxide (SiO.sub.x), aluminum oxide (AlO.sub.x), and acrylate-based polymers.

35. The heat-sterilizable multilayer film of claim 34, wherein the functional layer (D) consists of PET/SiO.sub.x.

36. A method for producing a laminated multilayer film sleeve made of the heat-sterilizable multilayer film of claim 34, comprising the following steps: (a) producing a film sleeve made of a multilayer film, wherein the first polymer layer (A), the central polymer layer (C), and the second polymer layer (B) are coextruded, and wherein the interior of the film sleeve is flooded with 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 of the 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 of the first polymer layer (A) of the film sleeve coated with the pressure-sensitive adhesive layer with the functional layer (D); and (f) optionally drying and curing the laminated film sleeve.

37. A medical package comprising the heat-sterilizable multilayer film of claim 20 or 34.

38. A method for producing the medical package made of the heat-sterilizable multilayer film of claim 20 or 34, comprising the steps of: a) providing at least one heat-sterilizable multilayer film, wherein the first polymer layer (A), the central polymer layer (C), and the second polymer layer (B) are coextruded; b) optionally providing one or more port elements and/or flexible tubes; c) shaping the medical package from the at least one heat-sterilizable multilayer film, wherein the second polymer layer (B) forms the inner face of the medical package and the first polymer layer (A) forms the outer face of the medical package; d) optionally positioning the port elements and/or flexible tubes between the inner faces at the contours of the medical package; e) contacting the inner faces with one another and with port elements and/or flexible tubes optionally positioned in between at the contours of the medical package; and f) heat-sealing the inner faces with one another and with port elements and/or flexible tubes optionally positioned in between at the contours of the medical package.

39. A method for producing the medical package made of the heat-sterilizable multilayer film of claim 20 or 34, comprising the steps of: a) providing at least one heat-sterilizable multilayer film; b) optionally providing one or more port elements and/or flexible tubes; c) shaping the medical package from the at least one heat-sterilizable one multilayer film, wherein the second polymer layer (B) forms the inner face of the medical package and the first polymer layer (A) forms the outer face of the medical package; d) optionally positioning the port elements and/or flexible tubes between the inner faces at the contours of the medical package; e) contacting the inner faces with one another and with port elements and/or flexible tubes optionally positioned in between at the contours of the medical package; and f) heat-sealing the inner faces with one another and with port elements and/or flexible tubes optionally positioned in between at the contours of the medical package, wherein the heat-sterilizable multilayer film is produced by the following steps: (1) producing a film sleeve made of a multilayer film, wherein the first polymer layer (A), the central polymer layer (C), and the second polymer layer (B) are coextruded, and wherein the interior of the film sleeve is flooded with air; (2) optionally cooling the film sleeve produced in method step (1); (3) coating the optionally cooled film sleeve with a pressure-sensitive adhesive layer on at least one side of the first polymer layer (A) of the film sleeve; (4) optionally drying the film sleeve provided with the pressure-sensitive adhesive layer; (5) laminating the at least one side of the first polymer layer (A) of the film sleeve coated with the pressure-sensitive adhesive layer with the functional layer (D); and (6) optionally drying and curing the laminated film sleeve.

Description

EXAMPLE 1

[0204] First Polymer Layer (A): [0205] 97% by weight of Moplen? HP525J from Lyondell Basell Corp., USA/propylene homopolymer [0206] 3% by weight of Tuftec? H1062 from Asahi Kasei, Japan/styrene-ethylene/butylene block copolymer

[0207] The stated formulation was homogeneously mixed in the melt state in a separate compounding step, extruded, and granulated for further use.

[0208] Second Polymer Layer (B): [0209] B1) 75% by weight of Tosoh FY-13 from Tosoh Corp., Japan//composite composed of ethylene homopolymer (70% to 80% by weight) and ethylene-1-butene copolymer (20% to 30% by weight)/density: 950 kg/m.sup.3, T.sub.m: 128? C. [0210] B2) 20% by weight of Bormed? TD109CF from Borealis, Austria/propylene terpolymer [0211] B3) 5% by weight of Engage? 8003 from Dow Chemical Company, USA/ethylene-octene polyolefin elastomer

[0212] The stated formulation was homogeneously mixed in the melt state in a separate compounding step, extruded, and granulated for further use.

[0213] Central Polymer Layer (C): [0214] C1) 70% by weight of Bormed? TD109CF from Borealis, Austria/propylene terpolymer [0215] C2) 20% by weight of Tuftec? H1062 from Asahi Kasei, Japan/styrene-ethylene/butylene block copolymer [0216] C3) 10% by weight of Engage? 8003 from Dow Chemical Company, USA/ethylene-octene polyolefin elastomer

[0217] The stated formulation was homogeneously mixed in the melt state in a separate compounding step, extruded, and granulated for further use.

[0218] The melts from the granulated compounds of the first polymer layer (A), the central polymer layer (C) and the second polymer layer (B) were coextruded on a blown-film line with water cooling using process parameters customary for polypropylene, and a multilayer film was obtained in the form of a film sleeve, the interior of which was flooded with sterile-filtered air.

[0219] The film was made with a total thickness of 200 ?m, with the first polymer layer (A) and second polymer layer (B) both having a thickness of 15 ?m and the central polymer layer (C) having a thickness of 170 ?m.

[0220] The film produced is sterilizable with hot steam and is already permanently heat-sealable with welding tools adjusted to a temperature of 125? C.

EXAMPLE 2

[0221] A film sleeve produced according to Example 1 was additionally provided with a functional layer (D) composed of SiO.sub.x/PET (Techbarrier T from Mitsubishi) on both sides in a layer thickness of 15 ?m in each case.

[0222] A two-component adhesive (Dow ADCOTE 811A+ADCOTE 811B coreactant, and Dow Catalyst 9L10, available from Dow Chemical) was first applied to both sides of the film sleeve laid flat, and the film sleeve provided with the adhesive was then laminated on both sides with the functional layer.

[0223] The film produced is sterilizable with hot steam and is already permanently heat-sealable with welding tools adjusted to a temperature of 125? C.

EXAMPLE 3 (COMPARATIVE EXAMPLE ACCORDING TO EXAMPLE 1 OF DE 10361851 A1)

[0224] First Polymer Layer (A): [0225] 97% by weight of Moplen? HP525J from Lyondell Basell Corp., USA/polypropylene homopolymer [0226] 3% by weight of Tuftec? H1062 from Asahi Kasei, Japan/styrene-ethylene/butylene block copolymer

[0227] The stated formulation was mixed in the melt state in a separate compounding step and granulated for further use.

[0228] Second Polymer Layer (B): [0229] 85% by weight of Bormed? TD109CF from Borealis, Austria/propylene terpolymer [0230] 15% by weight of Tuftec? H1062 from Asahi Kasei, Japan/styrene-ethylene/butylene block copolymer

[0231] The stated formulation was mixed in the melt state in a separate compounding step and granulated for further use.

[0232] Central Polymer Layer (C): [0233] 75% by weight of Bormed? TD109CF from Borealis, Austria/propylene terpolymer [0234] 20% by weight of Tuftec? H1062 from Asahi Kasei, Japan/styrene-ethylene/butylene block copolymer [0235] 5% by weight of Engage? 8003, Dow Chemical Company, USA/ethylene-octene polyolefin elastomer

[0236] The stated formulation was mixed in the melt state in a separate compounding step and granulated for further use.

[0237] The film was coextruded on a blown-film line with water cooling using process parameters customary for polypropylene.

[0238] The film was made with a total thickness of 200 ?m, with the first polymer layer (A) and second polymer layer (B) both having a thickness of 15 ?m and the central polymer layer (C) having a thickness of 170 ?m. The film produced is sterilizable with hot steam and is permanently heat-sealable with welding tools adjusted to a temperature of 125? C.

EXAMPLE 4 (NOT ACCORDING TO THE INVENTION, COMPARISON)

[0239] First Polymer Layer (A): [0240] 97% by weight of Moplen? HP525J from Lyondell Basell Corp., USA/polypropylene homopolymer [0241] 3% by weight of Tuftec? H1062 from Asahi Kasei, Japan/styrene-ethylene/butylene block copolymer

[0242] The stated formulation was homogeneously mixed in the melt state in a separate compounding step, extruded, and granulated for further use.

[0243] Second Polymer Layer (B): [0244] 75% by weight of Bormed? LE6600-PH from Borealis, Austria/low-density polyethylene (LDPE) [0245] 20% by weight of Bormed? TD109CF from Borealis, Austria/propylene terpolymer [0246] 5% by weight of Engage? 8003 from Dow Chemical Company, USA/ethylene-octene polyolefin elastomer

[0247] The stated formulation was homogeneously mixed in the melt state in a separate compounding step, extruded, and granulated for further use.

[0248] Central Polymer Layer (C): [0249] 70% by weight of Bormed? TD109CF from Borealis, Austria/propylene terpolymer [0250] 20% by weight of Tuftec? H1062 from Asahi Kasei, Japan/styrene-ethylene/butylene block copolymer [0251] 10% by weight of Engage? 8003, Dow Chemical Company, USA/ethylene-octene polyolefin elastomer

[0252] The stated formulation was homogeneously mixed in the melt state in a separate compounding step, extruded, and granulated for further use.

[0253] The granulated compounds of the polymer layers (A), (B) and (C) were coextruded on a blown-film line with water cooling using process parameters customary for polypropylene, and a multilayer film was obtained in the form of a film sleeve.

[0254] The film was made with a total thickness of 200 ?m, with the first polymer layer (A) and second polymer layer (B) both having a thickness of 15 ?m and the central polymer layer (C) having a thickness of 170 ?m.

[0255] Testing of the Weld Strength of Films of Examples 1 to 4 [0256] 1. (a) Preparation of heat-sealed samples using a film sealing unit (IST Med from Kopp) from 2 films lying on top of one another (each 20?15 cm); weld region (film edge) ?15 mm. [0257] Welding parameters: pressure: 2-3 bar, time: 1-2 seconds, gap: 320 ?m. [0258] (b) followed by punch-out of 15?80 mm wide test strips with heat-sealed edge (=unsterilized samples). [0259] 2. Hot-steam sterilization at 121? C. (WEBECO type A 35 autoclave, 2 bar, 20 minutes) of some of the test strips with heat-sealed edge that have been obtained (=hot steam-sterilized samples). Film cohesion is prevented by opening the non-heat-sealed regions of the test strips beforehand and placing paper in between. [0260] 3. Determination of weld strength by clamping the cooled test strips with heat-sealed edge in a tensile testing machine (Zwick iLine 500N from Zwick) and pulling the test strips at a rate of 400 mm/min.

[0261] The results for weld assessment are reported in N/15 mm.

[0262] The weld strength of the multilayer film should be greater than 25 N/15 mm, preferably greater than 30 N/15 mm. If the weld strength of the multilayer film is 10 to 20 N/15 mm, it has a peelable seam.

[0263] FIG. 1 shows weld curves of unsterilized samples according to Examples 1 to 4. The x-axis indicates the welding temperature [? C.]; the y-axis indicates the tensile strength [N/15 mm].

[0264] FIG. 2 shows weld curves of hot steam-sterilized samples according to Examples 1 to 4. The x-axis indicates the welding temperature [? C.]; the y-axis indicates the tensile strength [N/15 mm].

[0265] In the figures, the individual examples are shown by different line structures.

[0266] Results:

[0267] (a) Unsterilized Samples

[0268] The weld curves (see FIG. 1) of the films of Examples 1, 3 and 4 have a weld strength of >30 N/15 mm at approx. 130? C.; the film of Example 2 having the PET/SiO.sub.x functional layer starts to heat-seal (weld strength >30 N/15 mm) at a temperature higher by about 5? C., which is not a problem because of the higher temperature resistance of the film due to the PET/SiO.sub.x functional layer.

[0269] (b) Hot Steam-Sterilized Samples

[0270] The weld curves (see FIG. 2) of the films of Examples 1, 2 and 3 are similar to those of the unsterilized samples, i.e. they have a weld strength of >30 N/15 mm at approx. 130? C. or 135? C.; the film of Example 4 (second polymer layer based on LDPE) does not show the desired weld strength after hot-steam sterilization. It is apparent that the weld is separated or peeled, or delaminated. If films according to Example 4 were to be used as medical bags, the bags would open during sterilization in an autoclave or when removed.

[0271] PE materials such as LDPE or HDPE are incompatible with polypropylene, i.e. in the case of multilayer films having PP-based central layers, the inner layer separates easily from the central layer. Furthermore, the melting temperature of LDPE raw materials is between 110? C. and 115? C., i.e. the raw material melts during hot-steam sterilization and weakens the weld.

[0272] Owing to the specific combination used for the second polymer layer (inner layer) B), said combination being that of a polyethylene-based composite B1), a PP terpolymer B2) and a polyethylene elastomer B3) (as adhesion promoter), the multilayer film according to the invention in accordance with Examples 1 and 2 is shown to have the advantage that the inner layer B) cannot be easily detached from the central layer C); furthermore, the composite B1) used is shown not to melt during hot-steam sterilization, the weld strength consequently remaining sufficiently high.

[0273] Compared to the prior-art multilayer films in accordance with Example 3 (inner layer B composed of impact-modified propylene terpolymer), the multilayer films of Examples 1 and 2 according to the invention have a very good impact strength even without the addition of an impact modifierowing to the polyethylene-based composite B1) used for the inner layer B)and they have a comparable weld strength and suitability for hot-steam sterilization. Furthermore, multilayer films according to the invention have the advantage over those in accordance with Example 3 that active ingredients are less strongly adherent to the PE-containing inner layer, i.e. the so-called recovery value is higher.