SG177232A1

SG177232A1 - Medical laminated film

Info

Publication number: SG177232A1
Application number: SG2011016789A
Authority: SG
Inventors: Kazuhito Kanayama; Yama Masaaki Kuri
Original assignee: Shikoku Kakoh Co Ltd; Baxter Ltd; Baxter Int; Baxter Healthcare Sa
Priority date: 2010-07-12
Filing date: 2010-07-12
Publication date: 2012-02-28
Also published as: JP5278543B2; WO2012008007A1; JPWO2012008007A1

Abstract

MEDICAL LAMINATED FILMThe present invention provides a medical laminated film which is excellent in flexibility even after subjected to high-pressure steam sterilization. The medical laminated film of the present invention comprises at least an A layer, a B layer, a C layer, a D layer and an E layer which are successively laminated in this order, wherein the A layer comprises a polyester-based resin or a polyamide resin, the B layer comprises an adhesive resin, the C layer comprises a polyolefin-based resin, the D layer comprises a polyolef in-based thermoplastic elastomer having a flexural modulus of not more than 300 (MPa), and the E layer comprises a polyolefin-based thermoplastic elastomer having a flexural modulus of 600 to 1500 (MPa), and wherein the A layer is disposed as an outermost layer, whereas the E layer is disposed as an innermost layer.

Description

SPECIFICATION :

MEDICAL LAMINATED FILM

TECHNICAL FIELD

[0001]

The present invention relates to a medical laminated film, and more particularly, to a medical laminated film which can be suitably used as a bag film for medicament solutions and waste solutions or liquid excretions for peritoneal dialysis, a film for transfusion bags, or the like.

BACKGROUND ART

[0002]

Conventionally, there have been proposed various films which are useful as medical laminated films. As an example of the medical laminated films, there is known a medical liquid receiving bag formed of a laminated film having a 5-layered structure which includes a polyester- based resin layer as an outermost layer, and an adhesive layer, a polyamide resin layer, an adhesive layer and a polyolefin layer which are successively laminated inwardly from the outermost layer (Patent Document 1).

PRIOR DOCUMENTS

Patent Document 1: Japanese Patent Application Laid-

Open (KOKAI) No. 2002-219786 :

SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0004]

However, in the above conventional medical liquid receiving bag, there tends to arise such a problem that the laminated film used therefor in which engineering plastics such as polyester-based resins and polyamide resins are used in not only an outermost layer but also an intermediate layer thereof is generally deteriorated in flexibility after subjecting the medical liquid receiving bag to high-pressure steam sterilization, although it can maintain physical strengths such as tensile strength without problems.

[0005]

The present invention has been accomplished to solve the above problem. An object of the present invention is to provide a medical laminated film which can maintain similar good physical strengths such as tensile strength and can still exhibit an excellent flexibility even after subjected to high-pressure steam sterilization, as compared to the above conventional laminated film using the engineering plastics such as polyester-based resins and polyamide resins in not only an outermost layer but

. | -3- also an intermediate layer thereof.

MEANS FOR SOLVING THE PROBLEMS

[0006]

That is, according to the present invention, there is provided a medical laminated film comprising at least an A layer, a B layer, a C layer, a D layer and an E layer which are successively laminated in this order, the A layer comprising a polyester-based resin or a polyamide resin, the B layer comprising an adhesive resin, the C layer comprising a polyolefin-based resin, the D layer comprising a polyolefin-based thermoplastic elastomer having a flexural modulus of not more than 300 (MPa), and the E layer comprising a polyolefin-based thermoplastic elastomer having a flexural modulus of 600 to 1500 (MPa), the A layer being disposed as an outermost layer, and the E layer being disposed as an innermost layer.

EFFECT OF THE INVENTION :

[0007]

In accordance with the present invention, there is provided a medical laminated film which is excellent in both physical strengths such as tensile strength and

~ flexibility.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0008]

The present invention is described in detail below.

The medical laminated film according to the present invention comprises at least an A layer, a B layer, a C layer, a D layer and an E layer which are successively : laminated in this order.

[0009]

The A layer comprises a polyester-based resin or a polyamide resin. Examples of the polyester-based resin suitably usable in the present invention include homopolymers and copolymers of polybutylene terephthalate (PET). Examples of the polyamide resin suitably used in the present invention include polyamide 6 and copolymers of polyamide 6 and polyamide 66. As these polyester-based resin and polyamide resin, there may be used known polymers (resins) ordinarily used in the applications of packaging films. As the comonomer components of the copolymers, there may be respectively mentioned the following components.

[0010]

That is, examples of the dicarboxylic acid component include isophthalic acid, phthalic acid, 2,6- naphthalenedicarboxylic acid, adipic acid, sebacic acid a -5- and oxycarboxylic acids (such as, e.g., p-oxybenzoic acid).

Examples of the glycol component include ethylene glycol, diethylene glycol, propylene glycol, 1,4-cyclohexane dimethanol, neopentyl glycol, polyethyleneoxide glycol, polypropyleneoxide glycol and polytetramethyleneoxide glycol. These dicarboxylic acid components and glycol components may be respectively used in combination of any two or more thereof. The content of the PBT unit derived from terephthalic acid and butylene glycol in the copolymers is usually 70 to 99 mol% and preferably 85 to 99 mol%, and the remainder units of the respective copolymers are derived from the above comonomer components.

[0011]

The B layer comprises an adhesive resin. As the adhesive resin, there may be preferably used, for example, modified polyolefin resins. The modified polyolefin resins may be produced by copolymerizing and/or graft- polymerizing a polyolefin resin comprising an ethylene component and/or a propylene component as a main constitutional component with an «,f-unsaturated carboxylic acid or a derivative thereof.

[0012]

Examples of the above polyolefin resin include polyethylene, polypropylene, ethylene-propylene copolymers, ethylene-butene-1 copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-

ethyl acrylate copolymers and ethylene-sodium acrylate copolymers.

[0013]

Examples of the above o,p-unsaturated carboxylic acid or a derivative thereof which is copolymerized with the polyolefin resin include acrylic acid, methacrylic acid, methyl methacrylate, sodium acrylate, zinc acrylate, vinyl acetate and glycidyl methacrylate. The content of the «,p- unsaturated carboxylic acid or a derivative thereof in a molecular chain of the modified polyolefin resin is within the range of not more than 40 mol%. Examples of the modified polyolefin copolymer resin include ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers and ethylene-sodium acrylate copolymers.

[0014]

Examples of the above a,B-unsaturated carboxylic acid or a derivative thereof which is graft-polymerized with the polyolefin resin include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, and an anhydride or an ester of these acids. Among these compounds used for modifying the polyolefin resin, especially preferred is maleic anhydride. The amount of the compound grafted to the polyolefin resin may be selected from the range of 0.01 to 25% by weight and preferably 0.05 to 1.5% by weight based on the polyolefin oC -7- resin.

[0015]

The graft reaction may be carried out by an ordinary method, usually by melting and mixing the polyolefin resin and the «,f-unsaturated carboxylic acid or a derivative thereof at a resin temperature of 150 to 300°C. Upon the graft reaction, in order to conduct the reaction in an efficient manner, an organic peroxide such as a,o'-bis-t- butylperoxy-p-diisopropyl benzene may added to the reaction system in an amount of 0.001 to 0.05% by weight.

[0016]

The C layer is constituted from a polyolefin-based resin layer. Examples of the polyolefin-based resin suitably used in the present invention include propylene random copolymer resins (R-PP), metallocene polypropylene resins (M-PP) and metallocene low-density polyethylene resins (M-PE).

[0017]

The above propylene random copolymer resins (R-PP) are in the form of a random copolymer of propylene and a small amount of an a-olefin. The o-olefin used above is an a-olefin having 2 to 8 carbon atoms except for propylene.

Specific examples of the o-olefin include ethylene, 1- butene, 3-methyl-l-butene, 3-methyl-l-pentene, 4-methyl-1- pentene and l-octene. Among these oa-olefins, preferred is oo -8- ethylene. The amount of the a-olefin to be copolymerized is usually 0.1 to 5% by weight and preferably 1.5 to 4% by weight. Examples of commercially available products of the propylene random copolymer resins (R-PP) include "NOVATEC

PP" (tradename) produced by Japan Polypropylene

Corporation, or the like.

[0018]

The above metallocene polypropylene resins (M-PP) are polypropylene resins obtained by using a metallocene catalyst. The melt index (MI) of the metallocene polypropylene resins (M-PP) is usually 0.1 to 20 g/min (230°C). Examples of commercially available products of the metallocene polypropylene resins (M-PP) include "WINTEC" (tradename) produced by Japan Polypropylene

Corporation, or the like.

[0019]

The above metallocene low-density polyethylene resins (M-PE) are low-density polyethylene resins obtained by using a metallocene catalyst. Among these low-density polyethylene resins, especially preferred are metallocene linear low-density polyethylene resins (M-LLDPE), i.e., copolymers of ethylene and an a-olefin having 3 to 13 carbon atoms (ethylene content: 86 to 99.5 mol%). Specific examples of the a-olefin include propylene, butene-1, hexene-1, 4-methyl pentene-1, octene-1, decene-1 and dodecene~1. The melt index (MI) of the metallocene linear oo 9 low-density polyethylene resins (M-LLDPE) is usually 0.1 to 20 g/min (230°C). Examples of commercially available products of the metallocene linear low-density polyethylene resins (M-LLDPE) include "KERNEL" (tradename) and "HARMOREX" (tradename) both produced by Japan

Polyethylene Corporation, or the like.

[0020]

The D layer and the E layer both comprise a polyoclefin-based thermoplastic elastomer (TPO). The polyolefin-based thermoplastic elastomer (TPO) may be, for example, of either a compound type which is produced by mechanically dispersing an ethylene/propylene rubber in polypropylene using a kneader to form a composite material thereof, or a reactor type which is produced by introducing a large amount of a ethylene/propylene rubber into propylene by polymerization therebetween. The flexural modulus (MPa) of the polyolefin-based thermoplastic elastomer (TPO) may be suitably adjusted by varying an amount of the ethylene/propylene rubber used therein. In the present invention, as described hereinafter, the respective polyolefin-based thermoplastic elastomers (TPO) used in the D layer and the E layer are different in flexural modulus (MPa) from each other.

Examples of commercially available products of the polyolefin-based thermoplastic elastomer (TPO) include "ZELAS" 7000 series produced by Mitsubishi Chemical oC -10-

Corporation.

[0021]

In the D layer, there is used the polyolefin-based thermoplastic elastomer (TPO) having a flexural modulus of not more than 300 (MPa), whereas in the E layer, there is used the polyolefin-based thermoplastic elastomer (TPO) having a flexural modulus of 600 to 1500 (MPa). The flexural modulus used herein is the value measured according to JIS-K-7203. As described above, when the flexural modulus of TPO used in the D layer which is disposed on an outer side of the E layer is smaller than that of TPO used in the E layer as an inner layer, the resulting laminated film is excellent in flexibility after subjected to high-pressure steam sterilization. Further, the laminated film is also excellent in impact strength upon falling ball impact test. On the contrary, if the resin having a smaller flexural modulus is used in the E layer as an inner layer, there tends to arise such a problem that a non-filled container or bag obtained from the laminated film suffers from severe blocking between inner surfaces thereof when subjected to high-pressure steam sterilization. In the present invention, the laminated film is free from the above blocking problem.

[0022]

The flexural modulus of the polyolefin-based thermoplastic elastomer (TPO) used in the D layer is oe -11- preferably not more than 100 (MPa). The lower limit of the flexural modulus of the polyolefin-based thermoplastic elastomer (TPO) is usually 30 (MPa). Also, the flexural modulus of the polyolefin-based thermoplastic elastomer (TPO) used in the E layer is preferably 700 to 1300 (MPa).

[0023]

The thicknesses of the respective A, B, C, D and E layers according to the present invention are as follows.

The thickness of the A layer is usually 3 to 30 um and preferably 6 to 12 um. The thickness of the B layer is usually 5 to 40 um and preferably 10 to 20 pm. The thickness of the C layer is usually 10 to 100 pm and preferably 50 to 80 pm. The thickness of the D layer is usually 10 to 60 um and preferably 30 to 50 um. The thickness of the E layer is usually 10 to 50 um and preferably 15 to 30 pum.

[0024]

The medical laminated film of the present invention may be produced, for example, by a down flow water cooling inflation molding method using a co-extrusion ring die or a laminating method. 2Among these methods, the down flow water cooling inflation molding method using a co- extrusion ring die is more preferably selected and used.

In the down flow water cooling inflation molding method, there may be usually used such a facility including the ring die, a water vessel which is disposed below the ring oC -12- die and equipped therein with a sizing ring, and a guide plate and a take-up roll which are successively disposed below the water vessel. In the method, plural kinds of raw material resins are co-extruded from the ring die sO as to undergo substantially no stretching, and passed : through the sizing ring for cooling the resin extruded.

Then, the resulting laminated film in the form of a cylindrical body is supplied to the take-up roll through the guide plate to fold the laminated film thereon, thereby obtaining the laminated film as a double film which is taken up on the roll. According to the above water cooling method, the cooling rate is high as compared to an air cooling method, so that the crystallinity of the resulting film is reduced to a low level. As a result, the obtained laminated film has advantages such as enhanced adhesion strength between the respective layers, a good flexibility and a high transparency. The cooling rate of the laminated film may be adjusted by controlling an amount and a temperature of cooling water. :

[0025]

The medical laminated film according to the present invention is excellent in both physical strengths such as tensile strength and flexibility and, therefore, can be suitably used as a film for transfusion bags, a bag film for medicament solutions and water solutions or liquid excretions for peritoneal dialysis, or the like.

oC -13-

EXAMPLES

[0026]

Next, the present invention is described in more detail below by Example. However, the present invention is not particularly limited to the following Example, and various modifications and changes are possible unless departing from the subject matters of the present invention. Meanwhile, in the following Example and

Comparative Examples, the flexibility of the laminated film was evaluated by the following method.

[0027] <Evaluation of flexibility>

The laminated film in the form of a tube was cut into a size of 22 cm x 30 cm to prepare a sample. The resulting sample was put into an outer bag (bag formed of a 75 um- thick high-density polyethylene single layer), and then the bag was sealed, placéd in a high-pressure steam sterilizer ("TOMY AUTOCLAVE 885-240" manufactured by Tomy

Seiko Co., Ltd.) and held therein at 121°C for 60 min.

Thereafter, the sample was removed from the bag and allowed to stand for cooling, and then cut into strip-like sheets along each of MD (machine or longitudinal direction) and TD (transverse or lateral direction) thereof to obtain test pieces each having a size of 0.5 cm x 18 cm. The thus obtained test pieces were respectively oC -14- deformed into a loop shape using a "loop stiffness tester” manufactured by Toyo Seiki Seisakusho Co., Ltd. A load cell was pushed by 1 cm against a looped portion of the respective test pieces at a low speed to measure a maximum load (flexibility) applied to the load cell. The smaller the measured maximum load, the higher the flexibility.

That is, the higher measured value of the maximum load indicates a harder film.

[0028]

Example and Comparative Examples 1 and 2:

The raw material resins as shown in Table 1 were co- extruded by a down flow water cooling molding method using a S-layer co-extrusion ring die, thereby producing a cylindrical body of a laminated film having a layer structure as shown in Table 2. The temperature of a mold of an extruder used was 250°C, the temperature of cooling water was 21°C, the amount of cooling water was 10 L/min, and the take-up speed of the laminated film was 15 m/min.

The thus obtained cylindrical body was slit into a sheet of the laminated film having a predetermined length and subjected to the above procedure for evaluating a flexibility thereof. The results are shown in Table 2.

oC -15-

[0029]

Table 1

Co-PBT PBT copolymer; p = 1.150; MFR = 22.0 g/min (250°C); melting point = 222°C ("NOVADURAN 55058" produced by Mitsubishi Engineering-

Plastics Corporation)

PP-AP (1) Adhesive resin (polypropylene-based maleic

EE g/min (230°C); melting point = 155°C

PP-AP(2) Adhesive resin (polypropylene-based maleic anhydride modified PO); p = 0.900; MFR = 3.2 g/min (190°C); melting point = 134°C ("MODIC

P604V" produced by Mitsubishi Chemical

Corporation)

PE-AP(1) Adhesive resin (polyethylene-based maleic

CU EREREE g/min (190°C); melting point = 119°C ("MODIC

M512" produced by Mitsubishi Chemical

Corporation) :

PE-AP(2) Adhesive resin (polyethylene-based maleic anhydride modified PO); p = 0.920; MFR = 0.8 g/min (1950°C); melting point = 122°C ("MODIC

M132" produced by Mitsubishi Chemical

Corporation)

Random-PP | Ethylene-propylene random copolymer; p = 0.990;

MFR = 1.7 g/min (230°C); melting point = 144°C ("NOVATEC PP/EG7C" produced by Japan

Polypropylene Corporation)

PO-based |PO-based thermoplastic elastomer; p = 0.890; MFR elastomer [= 1.6 g/min (230°C); melting point = 165°C; (1) flexural modulus = 50 MPa ("ZELAS" series produced by Mitsubishi Chemical Corp.)

PO-based |PO-based thermoplastic elastomer; p = 0.900; MFR = 2.0 g/min (230°C); melting point = 145°C; (2) flexural modulus = 800 MPa ("ZELAS" series produced by Mitsubishi Chemical Corporation) melting point = 205°C ("NOVAMID 2030CA" produced by Mitsubishi Engineering-Plastics Corporation)

Titel] Ee Cio 10a Goes melting point = 225°C ("NOVAMID 1022-1" produced by Mitsubishi Engineering-Plastics Corporation)

L-LDPE Linear low-density polyethylene; p = 0.926; MFR = 0.9 g/min (190°C); melting point = 123°C ( "NOVATEC LL/UF425" produced by Japan : Polyethylene Corporation)

oC -16-

[0030] : Table 2

Material Thickness | Flexibility (um) (MPa)

MD [ TD

Example 1 Co-PBT (outermost layer) 0.036 | 0.030 (1)

PO-based elastomer 16.5 (2) (innermost layer)

Comparative | Co-PBT (outermost 15.0

Example 1 layer) 0.056 | 0.056

Random-PP (innermost 39.0 layer)

Comparative | Co-PBT (outermost 10.5

Example 2 layer) 0.040 | 0.035

L-LDPE (innermost 72.0 layer)

[0031]

From the results shown in Table 2, it was apparently confirmed that the medical laminated film of the present invention in which the polyester-based resin or resin was not used in the respective layers other than an outermost layer thereof was excellent in flexibility even after subjected to high-pressure steam sterilization.

Claims

oC -17- CLAIMS

1. A medical laminated film comprising at least an A layer, a B layer, a C layer, a D layer and an E layer which are successively laminated in this order, the A layer comprising a polyester-based resin or a polyamide resin, © the B layer comprising an adhesive resin, the C layer comprising a polyolefin-based resin, the D layer comprising a polyolefin-based thermoplastic elastomer having a flexural modulus of not more than 300 (MPa), and the E layer comprising a polyolefin-based thermoplastic elastomer having a flexural modulus of 600 to 1500 (MPa), the A layer being disposed as an outermost layer, and the E layer being disposed as an innermost layer.

2. A medical laminated film according to claim 1, wherein the D layer has a flexural modulus of 30 to 100

MPa.

3. A medical laminated film according to claim 1 or 2, wherein the E layer has a flexural modulus of 700 to 1300

MPa.

4. A medical laminated film according to any one of

LC -18- claims 1 to 3, wherein the polyester-based resin used in the A layer is polybutylene terephthalate.

5. A medical laminated film according to any one of claims 1 to 4, wherein the polyolefin-based resin used in the C layer is a propylene-ethylene random copolymer.

6. A medical laminated film according to any one of claims 1 to 5, wherein the polyolefin-based thermoplastic elastomers used in the D layer and the E layer are in the form of a mixture of an ethylene-propylene elastomer and polypropylene.

7. A medical laminated film according claim 6, wherein the mixture of the ethylene-propylene elastomer and polypropylene is a reactor type material.

8. A medical laminated film according to any one of claims 1 to 7, wherein the medical laminated film is a co- extruded film.

9. A medical laminated film according claim 8, wherein the co-extruded film is produced by a co-extrusion water cooling inflation molding method.

10. A medical laminated film according any one of

LC -19- claims 1 to 9, wherein the medical laminated £ilm maintains a flexibility even after subjected to wet heating sterilization at 121°C for 60 min.

11. A medical laminated film according any one of claims 1 to 10, wherein the medical laminated film is used as a bag film for medicament solutions and waste solutions or liquid excretions for peritoneal dialysis.