JP2706025B2 - Multilayer film and container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer film and a container formed using the same. Specifically, it is used in the medical field, particularly for accommodating a drug solution, blood, or the like.

[0002]

2. Description of the Related Art Examples of conventional multi-layer medical containers include those made of the following polyethylene resins. * JP-A-62-64363 * Made of linear low-density polyethylene, the density of the inner and outer layers is 0.920 g / cm ³ or more, and the density of the intermediate layer is 0.920 g.
/ Bag less than ³ cm3.

* Japanese Patent Laid-Open No. 63-248633 * Three layers made of linear low-density polyethylene, the density of the inner and outer layers is 0.910 to 0.940 g / cm ³ , and the density of the intermediate layer is 0.880 to 0. in .905g / cm ^3, the container density difference between the two is 0.01 g / cm ³ or more. * JP-A-3-277365 * The outer layer is a linear low-density polyethylene having a density of 0.920 g / cm ³ or more, the intermediate layer is a linear low-density polyethylene having a density of 0.915 g / cm ³ or less, and the inner layer has a density of 0. 918 g / cm ³
A three-layer bag made of the above branched low-density polyethylene.

[0004]

However, the above has at least one of the following disadvantages.
-Since the inner and outer layers are made of low-density polyethylene resin, the heat resistance is not sufficient, and the seal strength and the drop strength are reduced by sterilization under high-temperature conditions such as high-pressure steam sterilization and hot water sterilization.

[0005] Especially, blocking tends to occur after high-temperature sterilization. * It is necessary to increase the thickness of the film in order to increase its strength. * The bag making speed cannot be increased due to insufficient tensile strength. * When performing heat sealing, it is not possible to seal in a short time because the temperature of the heater cannot be raised.

* Transparency and flexibility may decrease after sterilization. Then, in this invention, it aims at providing the film and container suitable for medical use which can solve the said subject.

[0007]

In order to achieve the above object, the multilayer film according to the present invention has an outer layer made of a polypropylene resin and an intermediate layer having a density of 0.9.
20 g / cm ³ or less of linear ethylene and α-olefin
Also made of single layer or multilayer is perforated with less polymer, the inner layer is a density 0.925 g / cm ³ or more linear ethylene · alpha-
It is characterized by being made of an olefin copolymer resin.

[0008] As a preferred embodiment of the present invention,
The outer layer of polypropylene resin is
What is a mixture with a ren / α-olefin copolymer
Can be mentioned. In another preferred embodiment,
Interlayer has a density of 0.920 g / cm^ThreeThe following linear ethylene
・ Α-olefin copolymer and density 0.900g / cm^Three
Mixing with the following ethylene / α-olefin elastomers
Including resin layer or density 0.920g / cm^ThreeLess than
Linear ethylene / α-olefin copolymer layers and densities
0.900 g / cm^ThreeThe following ethylene / α-olefins
Having at least two elastomer layers, and
Close to the linear ethylene / α-olefin copolymer in the inner layer
Degree 0.950g / cm^ThreeHigh density ethylene α-ole
A fin copolymer containing less than 15% by weight
Can be mentioned. Further, in another preferred embodiment,
Has a polypropylene resin layer as part of the intermediate layer
Things are shown.

Further, the medical container according to the present invention is characterized in that it is molded using the above-mentioned multilayer film. The multilayer film and the container according to the present invention have improved heat resistance as compared with conventional products and also have excellent blocking resistance, tensile strength, flexibility, and transparency,
The heat sealability is also good.

Next, the resin of each layer of the film and the container of the present invention and the method for producing the film and the container of the present invention will be described in more detail. * For the outer layer, a polypropylene resin is used because mechanical strength, transparency, and heat resistance are required. As the polypropylene, any of a propylene homopolymer, a random copolymer of propylene and another olefin, a block copolymer, and the like can be used. Among them, those having a melt flow rate (MFR) of 1 to 20 g / 10 min and a melting point of 140 to 170 ° C are particularly preferable. If necessary, an ethylene / α-olefin copolymer, particularly a linear ethylene / α-olefin copolymer having a density of about 0.880 to 0.920 g / cm ^3, is mixed at 10 to 30% by weight. Can also. The thickness is preferably 5 to 25% of the whole. * As the intermediate layer, a polyolefin resin layer having high flexibility and transparency is provided. As the polyolefin, a linear ethylene / α-olefin copolymer having a density of 0.920 g / cm ³ or less, preferably 0.905 g / cm ³ or less is used. In particular, an ethylene / α-olefin elastomer having a density of 0.900 g / cm ³ or less is added to the linear ethylene / α-olefin copolymer in an amount of 10 to 10 g / cm ^3.
By mixing 70% by weight or laminating both, flexibility can be further enhanced. Further, a polypropylene-based resin layer can be provided in a part of the intermediate layer, and the strength can be further increased. The polypropylene resin used in that case can be selected from those listed above as those used for the outer layer. In any case, the thickness of the flexible polyolefin resin layer is preferably 50 to 90% of the whole. * An anti-blocking and heat-resistant polyolefin resin is provided as the inner layer so that it can withstand sterilization under high-temperature conditions, does not cause blocking, and can be easily thermally welded. Specifically, density 0.925 g / cm ³ or more, is preferably used a density 0.930 g / cm ³ or more 0.950 g / cm ³ or less of linear ethylene · alpha-olefin copolymer. In order to increase heat resistance, a high-density ethylene / α-olefin copolymer having a density of 0.950 g / cm ³ or more can be mixed up to about 15% by weight. The thickness is preferably 5 to 25% of the whole. * The method for producing a multilayer film according to the present invention includes water-cooled or air-cooled coextrusion inflation, coextrusion T
A die method, a dry lamination method, an extrusion lamination method and the like can be mentioned, but a water-cooled coextrusion inflation method and a coextrusion T-die method are preferred from the viewpoint of performance, particularly transparency, economy and hygiene. In any of the methods, it is necessary to carry out the process at a temperature at which the resin of each layer is melted. However, if the temperature is too high, a part of the resin is thermally decomposed, and there is a possibility that the performance of the resin is reduced due to decomposition products. Therefore, the temperature conditions during the production of the film of the present invention are usually 150 to 250
° C, preferably 160 to 240 ° C.
In addition, it is preferable that the resin constituting each layer has a difference in MFR as small as possible in order to maintain transparency. * As a method for producing a container formed from a multilayer film according to the present invention, the tube-like or sheet-like film obtained as described above is cut and heat-sealed by an ordinary method, and the mouth member is heat-sealed. Attach and manufacture containers of predetermined shapes and dimensions. The conditions for heat sealing the film are as follows:
It can be raised to about 0 ° C., for example, for a film having a thickness of about 200 μ
It can be sealed in as short as 3 seconds. In addition, it is preferable that the mouth member is made of linear low-density polyethylene because the mouth member is well welded to the inner layer of the film of the present invention.

[0011]

EXAMPLES Examples of evaluation experiments on containers molded using the multilayer film according to the present invention will be described below.
First, a synthetic resin and a laminated sheet having a layer configuration shown in Table 1 were each formed by water-cooled co-extrusion inflation. Next, a medical container having a content of 500 ml was molded using these. In addition, the heat sealing of the film at the time of container molding was performed at 140 ° C. for 2 seconds.

Further, various properties of the obtained medical container were evaluated by the following methods. That is, with respect to the heat resistance, the state of deformation, bag breakage, and seal leakage after high-pressure steam sterilization at 110 ° C. for 40 minutes after filling the content liquid was visually observed. In the drop test, the container was refrigerated to about 4 ° C., and the container was dropped five times from three directions from a height of 1.2 m, and the state of bag breakage and seal leakage was visually observed.

The flexibility was determined by visually observing the spontaneous discharge of the liquid content, and measuring the film hardness with a loop stiffness tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.). here,
The hardness in the film extrusion direction is indicated by MD, and the hardness in the radial direction of the film is indicated by TD. Transparency was measured by visual observation after filling with distilled water and performing high-pressure steam sterilization, and further measuring the light transmittance at 450 nm.

In addition, a visual observation of the overall appearance is performed,
The condition of wrinkles, blocking, deformation, and bag breakage was examined. The abbreviations in Table 1 are as follows. PP = 9: 1 mixture of polypropylene random block copolymer and linear low density polyethylene (ethylene / 1-butene copolymer) [Mitsui Petrochemical; density =
0.910 g / cm ³ , MFR = 5.8 g / 10 min] PP = polypropylene homopolymer [Mitsui Petrochemical; density = 0.910 g / cm ³ , MFR = 11.0 g / 10 min] LL = linear low density Polyethylene (ethylene 1-
Butene copolymer) [Mitsui Petrochemical; density = 0.905 g / c
m ³ , MFR = 2.86 g / 10 min] LL = linear low-density polyethylene (ethylene 1-
Butene copolymer elastomer) [Mitsui Petrochemical; density = 0.880 g / cm ³ , MFR = 1.40 g / 10 min] LL = linear low density polyethylene (ethylene 1-
Butene copolymer) [Mitsui Petrochemical; density = 0.900 g / c
m ³ , MFR = 0.90 g / 10 min] LM = linear medium density polyethylene (ethylene 1-
Butene copolymer) [Mitsui Petrochemical; density = 0.940 g / c
m ³ , MFR = 2.10 g / 10 min] · LM = linear medium density polyethylene (ethylene 1-
Butene copolymer) [Mitsui Petrochemical; density = 0.930 g / c
m ³ , MFR = 2.10 g / 10 min] and high-density polyethylene (ethylene / 1-butene copolymer) [manufactured by Mitsui Petrochemical; density = 0.956 g / cm ³ , MFR = 9.
0g / 10 min], and ◎ indicates very good, は indicates good, Δ indicates slightly poor, and × indicates poor.

[0015]

[Table 1]

From Table 1 above, it is clear that the film and the container of the present invention are excellent in flexibility, heat resistance, strength and transparency.

[0017]

The multilayer film and container according to the present invention can withstand high-temperature sterilization such as high-pressure steam sterilization or hot water sterilization. * The thickness of the entire film can be reduced. * It has excellent tensile strength and can make bags at high speed.

* Less likely to cause blocking. * Heat sealing can be performed at high temperature in a short time, and the sealing property is good. * Excellent flexibility and transparency can be maintained after sterilization. It can be preferably used as a medical container such as an infusion bag or a blood bag.

Claims (6)

(57) [Claims] 1. An outer layer comprising a polypropylene-based resin, and an intermediate layer comprising a linear ethylene-ethylene resin having a density of 0.920 g / cm ³ or less.
also made of single layer or multilayer is perforated with less α- olefin copolymer, the inner layer is a density 0.925 g / cm ³ or more linear
A multilayer film comprising a linear ethylene / α-olefin copolymer resin. 2. The multilayer film according to claim 1, wherein the polypropylene resin of the outer layer is a mixture of polypropylene and an ethylene / α-olefin copolymer. 3. An intermediate layer comprising a linear ethylene / α-olefin copolymer having a density of 0.920 g / cm ³ or less and a density of 0.920 g / cm ³ or less.
Either contains a mixed resin layer with an ethylene / α-olefin-based elastomer of not more than 00 g / cm ³ or has a density of 0.920
The multilayer film of claim 1 having at least two layers of g / cm ³ or less of linear ethylene · alpha-olefin copolymer layer and density 0.900 g / cm ³ or less of the ethylene · alpha-olefin elastomer layer. 4. A high-density ethylene / α-olefin copolymer having a density of 0.950 g / cm ³ or more is mixed with the linear ethylene / α-olefin copolymer of the inner layer in an amount of 15% by weight or less. 2. The multilayer film according to 1 . Some of 5. The intermediate layer, the multilayer film according to any one of claims 1 to 4 having a polypropylene resin layer. 6. A container formed by using the multilayer film according to any one of claims 1 to 5 .