JP6771809B2 - Medical bag - Google Patents

Description

The present invention relates to a laminate having excellent hygiene, flexibility, transparency, luster, heat resistance, bag drop strength, etc., and a medical bag made of the same. The medical bag is provided as a medical bag for containing chemicals, blood, etc.

The medical bag is required to have transparency so that the content liquid can be visually recognized, flexibility from the viewpoint of dripping property of the content liquid, and heat resistance that does not impair the transparency and flexibility even by heat treatment such as sterilization. A polyethylene-based laminate has been studied as a resin material that meets the above requirements and has good hygiene, and many proposals have been made.

For example, the inner and outer layers are made of linear low-density polyethylene, which is an ethylene / α-olefin copolymer having a density of 0.910 to 0.940 g / cm ³ , and the intermediate layer is 0.880 to 0.905 g / cm ^3. It is made of linear low-density polyethylene, which is an ethylene / α-olefin copolymer having a density of, and has a three-layer structure in which a density difference of at least 0.01 g / cm ^{3 is} provided between the inner layer and the outer layer and the intermediate layer. Plastic containers have been proposed (see Patent Document 1). However, the above-mentioned plastic container has a big problem that the heat resistance is not sufficient. In particular, if the chemical solution is put into this container and then heat-pressurized and sterilized under a temperature condition of 110 ° C. or higher, the container may melt and no longer function as a container. Further, even if the shape of the container is retained, there is a problem that the transparency is lowered.

Further, an outer layer formed of linear polyethylene having a density of 0.910 g / cm ³ or more and less than 0.950 g / cm ³ and an inner layer formed of linear polyethylene having a density of 0.940 g / cm ³ or less. , At least one formed of linear polyethylene having a density between the outer layer and the inner layer, which is 0.920 g / cm ³ or less and has a density different from that of the linear polyethylene forming the outer layer and the inner layer. A linear polyethylene composition having an intermediate layer portion including an intermediate layer, and at least one layer of these layers contains 5 to 55% by weight of high-density polyethylene having a density of 0.950 g / cm ³ or more. A resin laminate characterized by being formed of (see Patent Document 2) has been proposed.

Further, the outer layer is formed of a polyolefin-based resin material having a specific Vicat softening temperature, and the inner layer is formed of a polyethylene-based material containing an ethylene / α-olefin copolymer containing a low crystal component and a high crystal component as a main component. A laminate has been proposed (see Patent Document 3).
Further, it is a laminate containing at least an outer layer, an intermediate layer and an inner layer in this order, in which the outer layer is formed of a polyolefin resin material having a specific Vicat softening temperature, and the intermediate layer has a specific ethylene / α-olefin copolymer weight. It is formed of an ethylene / α-olefin copolymer composition composed of a coalescence and a specific high-density polyethylene, and the inner layer is an ethylene / α-olefin composed of a specific ethylene / α-olefin copolymer and a specific high-density polyethylene. A laminate has been proposed which is formed of a copolymer composition and in which the ratio of high-density polyethylene in the intermediate layer and the inner layer satisfies a specific relationship (see Patent Document 4).

Further, it is a copolymer of an inner layer mainly composed of high-density polyethylene having a melting point of 128 ° C. or higher, ethylene produced by a metallocene-based catalyst, and α-olefin having 4 or more carbon atoms, and has a density of 0.920 g / cm. It is characterized in that it is formed of a laminated film composed of an intermediate layer containing ³ or less linear low-density polyethylene as a main component and an outer layer containing linear low-density polyethylene having a melting point of 128 ° C. or less as a main component. A polyethylene-based medical container has been proposed (Patent Document 5).

Further, it is a laminate having at least an inner layer, an intermediate layer and an outer layer, the inner layer is made of a resin material containing high-density polyethylene, and the intermediate layer is copolymerized with ethylene and α-olefin having 3 to 20 carbon atoms. The ethylene / α-olefin copolymer thus obtained, characterized in that it is made of a resin material having a main resistance of a polyethylene resin having specific physical properties, and the outer layer is made of a resin material containing high-density polyethylene. Laminates have been proposed. (Patent Document 6) However, even if the medical bag made of these laminates is subjected to heat-pressurization sterilization treatment under a temperature condition of 110 ° C. or higher, the possibility that the medical bag will melt and the shape will collapse is reduced. However, there is a problem that the optical characteristics such as transparency and gloss are inferior, and the visibility of the contents is inferior.

JP-A-63-248633 Japanese Unexamined Patent Publication No. 6-246886 Japanese Unexamined Patent Publication No. 2001-162746 Japanese Unexamined Patent Publication No. 2005-219485 Japanese Unexamined Patent Publication No. 2008-15549 Japanese Unexamined Patent Publication No. 2003-237002

An object of the present invention is to have high hygiene, excellent flexibility, transparency, and luster even after heat-pressurization sterilization under the condition of 110 ° C. or higher, and good bag-dropping strength in a low temperature atmosphere for medical use. To provide a bag. The medical bag is provided as a medical bag for containing chemicals, blood, etc.

As a result of diligent studies to solve the above problems, the present inventors have found that the above problems can be solved by using a specific ethylene / α-olefin copolymer. Further studies were carried out on these findings, and the present invention was completed.

That is, according to the first invention of the present invention, it is a medical bag composed of a laminated body in which at least the first layer, the second layer and the third layer are laminated in this order, and the first layer, the second layer and the third layer. The ratio of the following component (A) contained in all three layers and the component (A) contained in each resin layer is
A medical bag is provided that satisfies the relationship of 1st layer> 3rd layer> 2nd layer.
Component (A): Copolymer of ethylene having the following characteristics (Ai) and (Aii) and α-olefin having 3 to 12 carbon atoms (Ai) Melt flow rate (190 ° C., 21) .18N load) 0.1 to 10g / 10 minutes (A-iii) Density 0.930 to 0.950g / cm ³

According to the second invention of the present invention, in the first invention, the ethylene resin layer I in which the first layer contains 70 to 99% by weight of the component (A) and 1 to 30% by weight of the following component (C). The second layer is composed of an ethylene resin layer II containing 1 to 20% by weight of the component (A), 70 to 98% by weight of the following component (B), and 1 to 20% by weight of the following component (C). The third layer is characterized by being composed of an ethylene resin layer III containing 40 to 60% by weight of the component (A), 40 to 60% by weight of the following component (B), and 1 to 30% by weight of the following component (C). A medical bag is provided.

Component (B): Copolymer of ethylene and α-olefin having 3 to 12 carbon atoms produced by using a metallocene catalyst having the following characteristics (B-i) to (B-iv) (B-i) Melt flow rate (190 ° C, 21.18 N load) 0.1 to 20 g / 10 minutes (B-iii) Density 0.890 to 0.930 g / cm ³
(B-iii) α-olefin content is 5-40% by weight
(B-iv) The ratio (Mz / Mn) of the Z average molecular weight (Mz) to the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 8.0 or less.

Component (C): High-pressure low-density polyethylene (C-i) melt flow rate (190 ° C., 21.18 N load) having the following characteristics (C-i) to (C-ii) is 0.1 to 5 g / 10 minutes (C-ii) Density is 0.915 to 0.935 g / cm ³

According to the third invention of the present invention, in the first or second invention, the first layer is an ethylene resin layer containing 80 to 95% by weight of the component (A) and 5 to 20% by weight of the component (C). The second layer is composed of an ethylene resin layer II composed of I and containing 1 to 20% by weight of the component (A), 70 to 98% by weight of the component (B) and 1 to 20% by weight of the component (C). The medical treatment characterized in that the three layers are composed of an ethylene resin layer III containing 40 to 60% by weight of the component (A), 40 to 60% by weight of the component (B) and 1 to 30% by weight of the component (C). A bag is provided.

According to a fourth aspect of the present invention, there is provided a medical bag according to any one of the first to third aspects, wherein the total thickness of the laminate is 100 to 700 μm.

According to the fifth invention of the present invention, in any one of the first to fourth inventions, the laminated body is formed in a bag shape, the first layer is an outer layer, and the third layer is an inner layer. A medical bag is provided.

According to a sixth aspect of the present invention, there is provided a medical bag in which the third layers of the laminate face each other and are heat-sealed in a bag shape in any one of the first to fifth aspects. ..

Hereinafter, the medical bag will be described in detail for each item.

The medical bag of the present invention is a medical bag composed of a laminated body in which at least the first layer, the second layer and the third layer are laminated in this order, and the medical bag of the first layer, the second layer and the third layer. All of them contain the component (A) which is a specific ethylene / α-olefin copolymer, and the ratio of the component (A) contained in each resin layer is 1st layer> 3rd layer> 2nd layer. It is a medical bag that satisfies the layer relationship.
Preferably, the first layer is composed of an ethylene resin layer I containing a specific ethylene / α-olefin copolymer (A) and a specific high-pressure low-density polyethylene, and the second layer is a specific ethylene / α. It is composed of an ethylene resin layer II containing a specific ethylene / α-olefin copolymer (B) produced by using an olefin (A) and a metallocene catalyst and a specific high-pressure low-density polyethylene (C). The three layers contain a specific ethylene / α-olefin (A), a specific ethylene / α-olefin copolymer (B) produced using a metallocene catalyst, and a specific high-pressure low-density polyethylene (C). It is a medical bag made of an ethylene resin layer III.

1. 1. First Layer The first layer of the laminate of the present invention is preferably an ethylene / α-olefin copolymer (component (A)) of 70 to 90% by weight and high-pressure low-density polyethylene (component (C)) of 1 to 30. Contains% by weight.

(1) Ingredient (A)
The ethylene / α-olefin copolymer (component (A)) used for the first layer of the laminate of the present invention is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. The copolymer is an ethylene / α-olefin copolymer having the following properties (Ai) and (Aii).
Hereinafter, the constituent monomers, the polymerization method, and the characteristics thereof will be sequentially described.

(Ai) Melt Flow Rate (MFR)
The MFR (190 ° C., 21.18 N load) of ethylene / α-olefin (A) used in the first layer of the laminate of the present invention is 0.1 to 10 g / 10 minutes, preferably 0.1 to 4 minutes. It is .5 g / 10 minutes, more preferably 0.5 to 3.0 g / 10 minutes, and even more preferably 1.0 to 2.5 g / 10 minutes. If the MFR of the ethylene / α-olefin copolymer (A) is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability becomes poor, and if it exceeds 10 g / 10 minutes, bubbles become unstable during inflation molding. It is not preferable because it may show poor heat resistance such as poor moldability and wrinkles on the film after heat pressure sterilization treatment at 111 ° C.
Here, the MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(A-ii) Density The density of the ethylene / α-olefin copolymer (A) used in the first layer of the laminate of the present invention is 0.930 to 0.950 g / cm ³ , preferably 0.933 to 0. It is .945 g / cm ³ , more preferably 0.934 to 0.940 g / cm ³ , and even more preferably 0.935 to 0.939 g / cm ³ . The density of less than 0.930 g / cm ³ of ethylene · alpha-olefin copolymer (A), there is a possibility that the medical bag melts after 111 ° C. heat autoclaved, a 0.945 g / cm ³ If it exceeds, the transparency may decrease, which is not preferable.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of density polyethylene).

(A-iii) Monomer Composition The ethylene / α-olefin copolymer (A) used in the first layer of the laminate of the present invention is a random ethylene and α-olefin containing a structural unit derived from ethylene as a main component. It is a copolymer.
The α-olefin used as the comonomer is preferably an α-olefin having 3 to 12 carbon atoms. Specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4,4-dimethylpentene- The first prize can be mentioned. Specific examples of such ethylene / α-olefin copolymers include ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, and ethylene. -Examples include 4-methyl-pentene-1 copolymer. Further, the α-olefin may be one kind or a combination of two or more kinds. When two kinds of α-olefins are combined to form a terpolymer, examples thereof include ethylene / propylene / hexcentric polymer, ethylene / butene / hexcenter polymer, ethylene / propylene / octeneterpolymer, and ethylene / butene / octeneterpolymer. ..

(A-iv) Polymerization catalyst and polymerization method The ethylene / α-olefin copolymer (A) used for the first layer of the laminate of the present invention uses a Ziegler catalyst, a vanadium catalyst, a metallocene catalyst, preferably a metallocene catalyst. Can be manufactured. Examples of the production method include a high-pressure ion polymerization method, a vapor phase method, a solution method, and a slurry method.

(2) Ingredient (C)
The high-pressure low-density polyethylene (component (C)) used for the first layer of the laminate of the present invention has the following characteristics (C-i) to (C-ii).

(C-i) Melt Flow Rate (MFR)
The MFR (190 ° C., 21.18 N load) of the high-pressure low-density polyethylene (C) used for the first layer of the laminate of the present invention is 0.1 to 5.0 g / 10 minutes, preferably 0.5. It is ~ 4.0 g / 10 minutes, more preferably 0.7 ~ 3.0 g / 10 minutes. If the MFR of the high-pressure method low-density polyethylene (C) is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability becomes poor, and if it exceeds 5.0 g / 10 minutes, bubbles become unstable during inflation molding and molding is performed. It is not preferable because it may cause poor properties.
Here, the MFR of the high-pressure low-density polyethylene is measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(C-ii) Density The density of the high-pressure low-density polyethylene (C) used for the first layer of the laminate of the present invention is 0.915 to 0.935 g / cm ³ , preferably 0.920 to 0.930 g / cm. It is cm ³ , more preferably 0.923 to 0.929 g / cm ³ . If the density of the high-density low-density polyethylene is less than 0.915 g / cm ³ , the medical bag may melt after the heat-pressurization sterilization treatment at 111 ° C. If it exceeds 0.935 g / cm ³ , the transparency becomes transparent. It is not preferable because it may decrease.
Here, the density of the high-pressure method low-density polyethylene is measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of low-density polyethylene).

(3) Other Additive Components The ethylene-based resin layer I of the present invention may contain other additional optional components as long as the effects of the present invention are not significantly impaired. Such optional components include antioxidants used in ordinary polyethylene resin materials (preferably phenolic and phosphorus antioxidants), antiblocking agents, neutralizing agents, heat stabilizers, and crystals. Examples thereof include nucleating agents, clearing agents, lubricants, colorants, dispersants, peroxides, fillers, fluorescent whitening agents and the like.
Further, in order to impart flexibility, rubber compounds such as ethylene / α-olefin elastomers such as EBR and EPR and styrene elastomers such as SEBS and HSBR can be blended.

(4) Blending ratio of component (A) and component (C) The blending ratio of the component (A) and the component (C) in the ethylene resin layer I of the present invention is 70 to 99% by weight of the component (A). The content is 1 to 30% by weight of the component (C), preferably 5 to 25% by weight of the component (C) with respect to 75 to 95% by weight of the component (A), and more preferably 80 to 90% by weight of the component (A). The component (C) is 10 to 20% by weight based on%.
When the blending ratio of the component (A) exceeds 99% by weight and the blending ratio of the component (C) is less than 1% by weight, the flexibility, bag drop strength, and transparency especially after the heat and pressure sterilization treatment at 111 ° C. It is not preferable because it may reduce the sex.
Further, if the blending ratio of the component (A) is less than 70% by weight and the blending ratio of the component (C) exceeds 30% by weight, the transparency may decrease, which is not preferable.

(5) Method for Adjusting Ethylene Resin Layer I The component (A) and the component (C) contained in the ethylene resin layer I can be blended according to a production method and adjusted by melt-kneading if necessary.

More specifically, the component (A) and the component (C) may be dry-blended in advance, and the blend may be directly put into the hopper of the molding machine. Further, the blended product can be melted and kneaded using an extruder, a lavender plastograph, a Banbury mixer, a kneader blender or the like, and pelletized by a commonly used method to produce a film or a sheet.

2. Second layer The second layer of the laminate of the present invention is preferably an ethylene / α-olefin copolymer (component (A)) of 1 to 20% by weight, and an ethylene / α-olefin copolymer (component (B)). It is composed of an ethylene resin layer II containing 70 to 99% by weight and 1 to 20% by weight of high-pressure low-density polyethylene (component (C)).

(1) Ingredient (A)
The ethylene / α-olefin copolymer (component (A)) used for the second layer of the laminate of the present invention is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. The copolymer is an ethylene / α-olefin copolymer having the following properties (Ai) and (Aii).
Hereinafter, the constituent monomers, the polymerization method, and the characteristics thereof will be sequentially described.

(Ai) Melt Flow Rate (MFR)
The MFR (190 ° C., 21.18 N load) of ethylene / α-olefin (A) used in the second layer of the laminate of the present invention is 0.1 to 10 g / 10 minutes, preferably 0.1 to 4 minutes. It is .5 g / 10 minutes, more preferably 0.5 to 3.0 g / 10 minutes, and even more preferably 1.0 to 2.5 g / 10 minutes. If the MFR of the ethylene / α-olefin copolymer (A) is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability becomes poor, and if it exceeds 4.5 g / 10 minutes, the bubbles become unstable during inflation molding. This is not preferable because it may cause poor moldability, wrinkles may occur on the film after the heat-pressurization sterilization treatment at 111 ° C., and the like may exhibit poor heat resistance.
Here, the MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(A-ii) Density The density of the ethylene / α-olefin copolymer (A) used in the first layer of the laminate of the present invention is 0.930 to 0.950 g / cm ³ , preferably 0.933 to 0. It is .945 g / cm ³ , more preferably 0.934 to 0.940 g / cm ³ , and even more preferably 0.935 to 0.939 g / cm ³ . The density of less than 0.930 g / cm ³ of ethylene · alpha-olefin copolymer (A), there is a possibility that the medical bag melts after 111 ° C. heat autoclaved, a 0.945 g / cm ³ If it exceeds, the transparency may decrease, which is not preferable.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of density polyethylene).

(A-iii) Monomer Composition The ethylene / α-olefin copolymer (A) used for the second layer of the laminate of the present invention is a random ethylene and α-olefin containing a structural unit derived from ethylene as a main component. It is a copolymer.

The α-olefin used as the comonomer is preferably an α-olefin having 3 to 12 carbon atoms. Specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4,4-dimethylpentene- The first prize can be mentioned. Specific examples of such ethylene / α-olefin copolymers include ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, and ethylene. -Examples include 4-methyl-pentene-1 copolymer. Further, the α-olefin may be one kind or a combination of two or more kinds. When two kinds of α-olefins are combined to form a terpolymer, examples thereof include ethylene / propylene / hexcentric polymer, ethylene / butene / hexcenter polymer, ethylene / propylene / octeneterpolymer, and ethylene / butene / octeneterpolymer. ..

(A-iv) Polymerization catalyst and polymerization method The ethylene / α-olefin copolymer (A) used for the second layer of the laminate of the present invention uses a Ziegler catalyst, a vanadium catalyst, a metallocene catalyst, preferably a metallocene catalyst. Can be manufactured. Examples of the production method include a high-pressure ion polymerization method, a vapor phase method, a solution method, and a slurry method.

(2) Ingredient (B)
The ethylene / α-olefin copolymer (component (B)) used for the second layer of the laminate of the present invention is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. The copolymer is an ethylene / α-olefin copolymer having the following properties (B-i) to (B-iv).
Hereinafter, the constituent monomers, the polymerization method, and the characteristics thereof will be sequentially described.

(Bi) Melt Flow Rate (MFR)
The MFR (190 ° C., 21.18 N load) of ethylene / α-olefin (B) used in the second layer of the laminate of the present invention is 0.1 to 20 g / 10 minutes, preferably 0.5 to 10 g. It is / 10 minutes, more preferably 0.7 to 2.0 g / 10 minutes. If the MFR of the ethylene / α-olefin copolymer (B) is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability becomes poor, and if it exceeds 10 g / 10 minutes, bubbles become unstable during inflation molding. It is not preferable because it may show poor heat resistance such as poor moldability and wrinkles on the film after heat pressure sterilization treatment at 111 ° C.
Here, the MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(B-ii) Density The density of the ethylene / α-olefin copolymer (B) used in the second layer of the laminate of the present invention is 0.890 to 0.930 g / cm ³ , preferably 0.900 to 0. It is .920 g / cm ³ , more preferably 0.905 to 0.910 g / cm ³ . Ethylene · alpha-olefin copolymer with a density of less than 0.890 g / cm ³ of (B), there is a possibility that the medical bag melts after 111 ° C. heat autoclaved, a 0.920 g / cm ³ If it exceeds, the transparency may decrease, which is not preferable.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of density polyethylene).

(B-iii) α-olefin content The content of α-olefin in the ethylene / α-olefin copolymer (B) used in the second layer of the laminate of the present invention is preferably 5 to 40% by weight. , More preferably 7 to 35% by weight, still more preferably 9 to 30% by weight. If the α-olefin content is low, the impact strength and flexibility of the film cannot be obtained, and if it is too high, the heat resistance is impaired. Here, the content of α-olefin is a value measured by the 13C-NMR method under the following conditions.
Equipment: JEOL-GSX270 manufactured by JEOL
Concentration: 300 mg / 2 mL
Solvent: Orthodichlorobenzene The ethylene / α-olefin copolymer may be one kind or a mixture of two or more kinds.

(B-iv) Ratio (Mz / Mn) of Z average molecular weight (Mz) to number average molecular weight (Mn)
Since the Z average molecular weight (Mz) greatly contributes to the average molecular weight of the high molecular weight component, the ratio (Mz / Mn) of Mz to the number average molecular weight (Mn) is the ratio of the weight average molecular weight (Mw) to Mn. It is easier to confirm the presence of high molecular weight components as compared with (Mw / Mn). The high molecular weight component is a factor that affects the resin pressure during molding, and if the high molecular weight component is large, it becomes a problem during processing. Therefore, it is preferable that Mz / Mn is small.

Therefore, the ratio (Mz / Mn) of the Z average molecular weight (Mz) to the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) of the component (B) used in the present invention is 8.0 or less. Yes, preferably 5.0 or less. When Mz / Mn exceeds 8.0, the transparency deteriorates. Moreover, as a method of adjusting Mz / Mn to a predetermined range, a method of selecting an appropriate metallocene catalyst and the like can be mentioned.
The measurement of (Mz / Mn) is performed by gel permeation chromatography (GPC), and the measurement conditions are as follows.

Equipment: Waters GPC 150C type detector: MIRAN 1A infrared spectrophotometer (measurement wavelength 3.42 μm)
Column: Showa Denko AD806M / S 3 pieces (Column calibration is a 0.5 mg / ml solution of Tosoh monodisperse polystyrene (A500, A2500, F1, F2, F4, F10, F20, F40, F288)) Then, the logarithmic value of the elution volume and the molecular weight was approximated by a quadratic equation. The molecular weight of the sample was converted to polyethylene using the viscosity equation of polystyrene and polyethylene. Here, the coefficient of the viscosity equation of polystyrene was α = 0. 723, logK = -3.967, and polystyrene has α = 0.733, logK = -3.407.)
Measurement temperature: 140 ° C
Concentration: 20 mg / 10 mL
Injection volume: 0.2 ml
Solvent: Orthodichlorobenzene Flow rate: 1.0 ml / min.

(3) Ingredient (C)
The high-pressure low-density polyethylene (component (C)) used for the second layer of the laminate of the present invention has the following characteristics (C-i) to (C-ii).
(C-i) Melt Flow Rate (MFR)
The MFR (190 ° C., 21.18 N load) of the high-pressure low-density polyethylene (C) used for the second layer of the laminate of the present invention is 0.1 to 5.0 g / 10 minutes, preferably 0.5. It is ~ 4.0 g / 10 minutes, more preferably 0.7 ~ 3.0 g / 10 minutes. If the MFR of the high-pressure method low-density polyethylene (C) is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability becomes poor, and if it exceeds 5.0 g / 10 minutes, bubbles become unstable during inflation molding and molding is performed. It is not preferable because it may cause poor properties.
Here, the MFR of the high-pressure low-density polyethylene is measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(C-ii) Density The density of the high-pressure low-density polyethylene (C) used for the second layer of the laminate of the present invention is 0.915 to 0.935 g / cm ³ , preferably 0.920 to 0.930 g /. It is cm ³ , more preferably 0.923 to 0.929 g / cm ³ . If the density of the high-density low-density polyethylene is less than 0.915 g / cm ³ , the medical bag may melt after the heat-pressurization sterilization treatment at 111 ° C. If it exceeds 0.935 g / cm ³ , the transparency becomes transparent. It is not preferable because it may decrease.
Here, the density of the high-pressure method low-density polyethylene is measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of density polyethylene).

(4) Other Additive Components The ethylene-based resin layer II of the present invention may contain other additional optional components as long as the effects of the present invention are not significantly impaired. Such optional components include antioxidants (preferably phenolic and phosphorus antioxidants) used in ordinary polyethylene resin materials, antiblocking agents, neutralizing agents, heat stabilizers, and crystals. Examples thereof include nucleating agents, clearing agents, lubricants, colorants, dispersants, peroxides, fillers, fluorescent whitening agents and the like.
Further, in order to impart flexibility, rubber compounds such as ethylene / α-olefin elastomers such as EBR and EPR and styrene elastomers such as SEBS and HSBR can be blended.

(5) Blending ratio of component (A), component (B) and component (C) The blending ratio of the component (A), the component (B) and the component (C) in the ethylene resin layer I of the present invention is the component. It is 70 to 99% by weight of the component (B) and 1 to 20% by weight of the component (C) with respect to 1 to 20% by weight of the component (A), and preferably, the component ( B) 75 to 95% by weight and component (C) 5 to 15% by weight, more preferably 80 to 90% by weight of component (B) and component (C) with respect to 7 to 13% by weight of component (A). It is 7 to 13% by weight.
If the blending ratios of the component (A), the component (B) and the component (C) do not satisfy the above range, the flexibility, bag-dropping strength and transparency particularly after the heat-pressurization sterilization treatment at 111 ° C. may decrease. , Not preferable.

(6) Method for Adjusting Ethylene Resin Layer II The components (A), components (B) and components (C) contained in the ethylene resin layer II are blended according to the production method, and are adjusted by melt-kneading as necessary. be able to.

More specifically, the component (A) and the component (C) may be dry-blended in advance, and the blend may be directly put into the hopper of the molding machine. Further, the blended product can be melted and kneaded using an extruder, a lavender plastograph, a Banbury mixer, a kneader blender or the like, and pelletized by a commonly used method to produce a film or a sheet.

3. 3. Third layer The third layer of the laminate of the present invention contains 40 to 60% by weight of an ethylene / α-olefin copolymer (component (A)) and 40 to 60% by weight of an ethylene / α-olefin copolymer (component (B)). It is composed of an ethylene resin layer III containing 60% by weight and 1 to 30% by weight of high-pressure low-density polyethylene (component (C)).

(1) Ingredient (A)
The ethylene / α-olefin copolymer (component (A)) used for the third layer of the laminate of the present invention is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. The copolymer is an ethylene / α-olefin copolymer having the following properties (A-i) to (A-iv).
Hereinafter, the constituent monomers, the polymerization method, and the characteristics thereof will be sequentially described.

(Ai) Melt Flow Rate (MFR)
The MFR (190 ° C., 21.18 N load) of the ethylene / α-olefin copolymer (A) used for the third layer of the laminate of the present invention is 0.1 to 10 g / 10 minutes, preferably 0. It is 1 to 4.5 g / 10 minutes, more preferably 0.5 to 3.0 g / 10 minutes, and even more preferably 1.0 to 2.5 g / 10 minutes. If the MFR of the ethylene / α-olefin copolymer (A) is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability becomes poor, and if it exceeds 4.5 g / 10 minutes, the bubbles become unstable during inflation molding. This is not preferable because it may cause poor moldability, wrinkles may occur on the film after the heat-pressurization sterilization treatment at 111 ° C., and the like may exhibit poor heat resistance.
Here, the MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(A-ii) Density The density of the ethylene / α-olefin copolymer (A) used in the third layer of the laminate of the present invention is 0.930 to 0.950 g / cm ³ , preferably 0.933 to 0. It is .945 g / cm ³ , more preferably 0.934 to 0.940 g / cm ³ , and even more preferably 0.935 to 0.939 g / cm ³ . The density of the ethylene · alpha-olefin copolymer is less than 0.930 g / cm ^3, there is a possibility that the medical bag melts after 111 ° C. heat autoclaved, exceeds 0.945 g / cm ^3, It is not preferable because the transparency may decrease.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of density polyethylene).

(A-iii) Monomer Composition The ethylene / α-olefin copolymer (A) used in the third layer of the laminate of the present invention is a random ethylene and α-olefin containing a structural unit derived from ethylene as a main component. It is a copolymer.
The α-olefin used as the comonomer is preferably an α-olefin having 3 to 12 carbon atoms. Specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4,4-dimethylpentene- The first prize can be mentioned. Specific examples of such ethylene / α-olefin copolymers include ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, and ethylene. -Examples include 4-methyl-pentene-1 copolymer. Further, the α-olefin may be one kind or a combination of two or more kinds. When two kinds of α-olefins are combined to form a terpolymer, examples thereof include ethylene / propylene / hexcentric polymer, ethylene / butene / hexcenter polymer, ethylene / propylene / octeneterpolymer, and ethylene / butene / octeneterpolymer. ..

(A-iv) Polymerization catalyst and polymerization method The ethylene / α-olefin copolymer (A) used for the third layer of the laminate of the present invention uses a Ziegler catalyst, a vanadium catalyst, a metallocene catalyst, preferably a metallocene catalyst. Can be manufactured. Examples of the production method include a high-pressure ion polymerization method, a vapor phase method, a solution method, and a slurry method.

(2) Ingredient (B)
The ethylene / α-olefin copolymer (component (B)) used for the third layer of the laminate of the present invention is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. The copolymer is an ethylene / α-olefin copolymer having the following properties (B-i) to (B-iv).
Hereinafter, the constituent monomers, the polymerization method, and the characteristics thereof will be sequentially described.

(Bi) Melt Flow Rate (MFR)
The MFR (190 ° C., 21.18 N load) of ethylene / α-olefin used for the third layer of the laminate of the present invention is 0.1 to 20 g / 10 minutes, preferably 0.5 to 10 g / 10 minutes. It is more preferably 0.7 to 2.0 g / 10 minutes. If the MFR of the ethylene / α-olefin copolymer is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability becomes poor, and if it exceeds 10 g / 10 minutes, bubbles become unstable during inflation molding and the moldability becomes poor. It is not preferable because it may be defective, or the film may wrinkle after heat pressure sterilization at 111 ° C. and may exhibit poor heat resistance.
Here, the MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(B-ii) Density The density of the ethylene / α-olefin copolymer (B) used in the third layer of the laminate of the present invention is 0.890 to 0.930 g / cm ³ , preferably 0.900 to 0. It is .920 g / cm ³ , more preferably 0.905 to 0.910 g / cm ³ . Ethylene · alpha-olefin copolymer with a density of less than 0.890 g / cm ³ of (B), there is a possibility that the medical bag melts after 111 ° C. heat autoclaved, a 0.920 g / cm ³ If it exceeds, the transparency may decrease, which is not preferable.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of density polyethylene).

(B-iii) α-olefin content The content of α-olefin in the ethylene / α-olefin copolymer (B) used in the third layer of the laminate of the present invention is preferably 5 to 40% by weight. , More preferably 7 to 35% by weight, still more preferably 9 to 30% by weight. If the α-olefin content is low, the impact strength and flexibility of the film cannot be obtained, and if it is too high, the heat resistance is impaired. Here, the content of α-olefin is a value measured by the 13C-NMR method under the following conditions.
Equipment: JEOL-GSX270 manufactured by JEOL
Concentration: 300 mg / 2 mL
Solvent: Orthodichlorobenzene The ethylene / α-olefin copolymer may be one kind or a mixture of two or more kinds.

(3) Ingredient (C)
The high-pressure low-density polyethylene (component (C)) used for the third layer of the laminate of the present invention has the following characteristics (C-i) to (C-ii).
(C-i) Melt Flow Rate (MFR)
The MFR (190 ° C., 21.18 N load) of the high-pressure low-density polyethylene (C) used for the third layer of the laminate of the present invention is 0.1 to 5.0 g / 10 minutes, preferably 0.5. It is ~ 4.0 g / 10 minutes, more preferably 0.7 ~ 3.0 g / 10 minutes. If the MFR of the high-pressure method low-density polyethylene (C) is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability becomes poor, and if it exceeds 5.0 g / 10 minutes, bubbles become unstable during inflation molding and molding is performed. It is not preferable because it may cause poor properties.
Here, the MFR of the high-pressure low-density polyethylene is measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(C-ii) Density The density of the high-pressure low-density polyethylene (C) used for the third layer of the laminate of the present invention is 0.915 to 0.935 g / cm ³ , preferably 0.920 to 0.930 g /. It is cm ³ , more preferably 0.923 to 0.929 g / cm ³ . If the density of the high-density low-density polyethylene is less than 0.915 g / cm ³ , the medical bag may melt after the heat-pressurization sterilization treatment at 111 ° C. If it exceeds 0.935 g / cm ³ , the transparency becomes transparent. It is not preferable because it may decrease.
Here, the density of the high-pressure method low-density polyethylene is measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of low-density polyethylene).

(4) Other Additive Components The ethylene-based resin layer II of the present invention may contain other additional optional components as long as the effects of the present invention are not significantly impaired. Such optional components include antioxidants (preferably phenolic and phosphorus antioxidants) used in ordinary polyethylene resin materials, antiblocking agents, neutralizing agents, heat stabilizers, and crystals. Examples thereof include nucleating agents, clearing agents, lubricants, colorants, dispersants, peroxides, fillers, fluorescent whitening agents and the like.

Further, in order to impart flexibility, rubber compounds such as ethylene / α-olefin elastomers such as EBR and EPR and styrene elastomers such as SEBS and HSBR can be blended.

(5) Blending ratio of component (A), component (B) and component (C)
The blending ratio of the component (A), the component (B) and the component (C) in the ethylene resin layer III of the present invention is 40 to 60% by weight of the component (B) with respect to 40 to 60% by weight of the component (A). And component (C) 1 to 30% by weight.
If the blending ratios of the component (A), the component (B) and the component (C) do not satisfy the above range, the flexibility, bag-dropping strength and transparency particularly after the heat-pressurization sterilization treatment at 111 ° C. may decrease. , Not preferable.

(6) Method for Adjusting Ethylene Resin Layer III The components (A), components (B) and components (C) contained in the ethylene resin layer III are blended according to the production method and adjusted by melt-kneading as necessary. be able to.

More specifically, the component (A) and the component (C) may be dry-blended in advance, and the blend may be directly put into the hopper of the molding machine. Further, the blended product can be melted and kneaded using an extruder, a lavender plastograph, a Banbury mixer, a kneader blender or the like, and pelletized by a commonly used method to produce a film or a sheet.

4. Relationship of the ratio of the component (A) of the first layer, the second layer and the third layer The content ratio (weight%) of the component (A) contained in the first layer, the second layer and the third layer of the laminate of the present invention. ) Satisfies the relationship of 1st layer> 3rd layer> 2nd layer, and "ratio of component (A) of 1st layer-ratio of component (A) of 3rd layer" is 20 to 80% by weight. It is preferable that it satisfies 30 to 70% by weight, more preferably 40 to 60% by weight.

The ratio of the component (A) of the first layer, the ratio of the component (A) of the second layer, and the ratio of the component (A) of the third layer are the relationship between the component (A)> the third layer> the ratio of the second layer. If it is not satisfied, it becomes difficult to balance heat resistance and bag drop strength, which is not preferable.

Further, if the "ratio of the component (A) of the first layer-the ratio of the component (A) of the third layer" is less than 20% by weight, it becomes difficult to balance heat resistance and transparency, which is not preferable. Further, if the "ratio of the component (A) of the first layer-the ratio of the component (A) of the third layer" exceeds 80% by weight, the heat resistance may be deteriorated and the transparency may be lowered, which is not preferable.

5. Laminated body The laminated body of the present invention may be obtained by laminating at least the first layer, the second layer and the third layer in this order, but in addition to the first layer, the second layer and the third layer. , Various layers generally used for such a laminate can be appropriately provided as needed. Specifically, a tangent layer or a gas barrier layer such as EVOH can be provided between various layers.
Further, the thickness of the laminate of the present invention is preferably 100 to 700 μm. If it is within the above range, a film having excellent transparency can be stably formed, which is preferable.
The method for producing the laminate of the present invention is not particularly limited and can be carried out by a known method. It is preferably produced by a water-cooled inflation method.

Specifically, the above-mentioned resin materials for the first layer, the second layer, and the third layer are co-extruded using an extruder and a circular die, respectively, and introduced into a water tank while expanding by injecting air into a molten tube and quenching. The film is formed by the water-cooled inflation molding method. The conditions of the water-cooled inflation method are not particularly limited, but examples thereof include a method of blowing downward and cooling with water confined inside, or water cooling using a sizing ring or a water tank type water cooling ring. The molding temperature is 160 to 280 ° C., preferably 170 to 230 ° C., and the water temperature for water cooling is 10 to 60 ° C., preferably 15 to 50 ° C.

6. Applications The medical bag made of the laminate of the present invention can be particularly suitably used for 111 ° C. sterilization applications that require heat resistance. Specific uses of the medical bag include an infusion bag, a container for injecting, discharging, and storing body fluids and chemicals, a peritoneal dialysis bag, an artificial dialysis bag, and the like.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The evaluation methods and resins used in Examples and Comparative Examples are as follows.

1. 1. Evaluation method of resin physical properties (1) Melt flow rate (MFR): As described above, the MFR of the ethylene / α-olefin copolymer is JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load). Measured according to.
(2) Density: As described above, the density of the ethylene / α-olefin copolymer was measured at 23 ° C. in accordance with JIS-K6922-2: 1997 Annex (in the case of low density polyethylene).
(3) Α-olefin content: As described above, the content of α-olefin was measured by the 13C-NMR method.
(4) Mz / Mn: As described above, it was measured by GPC.

2. Molding method of laminated body Using a 3 type 3-layer water-cooled inflation molding machine manufactured by Placo (die diameter: 100 mmφ, die lip: 3 mm, die temperature: 185 ° C.), the thickness of the first layer and the third layer is 30 μm, and the intermediate layer When the thickness was 190 μm, a tubular laminate having a folding diameter of 180 mm was formed.

3. 3. Evaluation Method of Laminated Body (1) Heat resistance: A cylindrical laminated body was cut out to a size of 210 mm, and one of the cut out pieces was heat-sealed using an impulse sealer to form a bag. Then, 500 ml of pure water was filled therein, and the other side was heat-sealed and sealed. The distance between the heat seals was 180 mm. The sample bag thus obtained is placed in a high-temperature high-pressure cooking sterilization tester (manufactured by Hisaka Works, RCS / 40 RTGN type) and then pressurized to raise the atmospheric temperature to 111 ° C or 115 ° C. , The temperature was maintained for 30 minutes. Then, it cooled to about 40 degreeC, and the sample bag was taken out from a tester. Hereinafter, this sterilized laminate (“sample bag”) will be referred to as “sterilized laminate”.
The heat resistance of the sample bag was evaluated according to the following criteria.
◯: There are almost no wrinkles. Or not at all.
×: There are many wrinkles. Alternatively, transparency is reduced.

(2) GLOSS
The measurement was performed with reference to JIS-Z8741. The GLOSS measurement was performed on the molded laminate and the laminate after the heat-pressurization sterilization treatment. The reflection angle was selected to be 20 °.
When GLOSS was measured for the laminate after the heat-pressurization sterilization treatment, the water filled therein was drained and the measurement was carried out one week later.

(3) Tension elastic modulus With reference to JIS-K7217, the MD direction (film or sheet pick-up direction) and TD direction (vertical to film or sheet pick-up) of the molded laminate and the laminate after heat-pressurization sterilization treatment. The 1% tensile modulus of elasticity (direction) was measured. The smaller this value is, the more flexible it is.
When measuring the tensile elastic modulus of the laminate after the heat-pressurization sterilization treatment, the water filled therein was drained and one week later.

(4) Dropping strength The water-containing laminates (2 pieces) after heat-pressurization sterilization are stored in an environment of 10 ° C for 24 hours, and then dropped on an iron plate in parallel from a height of 2 m at that temperature. evaluated. Evaluation was made based on the following criteria.
X: After heat-pressurization sterilization treatment, one or two laminates were ruptured.
◯: The situation was the same as before the drop test, and there was no problem with both of them.

4. Resin used (1) Component (A): As the ethylene / α-olefin copolymer component (A), the following three types of commercially available resins were used. It is shown in Table 1.
A-1: Novatec C6 SF941 manufactured by Japan Polyethylene Corporation (MFR 2.0 g / 10 min, density 0.936 g / cm ³ )
A-2: Novatec HD HM160 manufactured by Japan Polyethylene Corporation (MFR 5.0 g / 10 min, density 0.953 g / cm ³ )
(2) Component (B): The following resin produced with a metallocene catalyst was used as the ethylene / α-olefin copolymer component (B). It is shown in Table 1.
B-1: Harmorex NF324A manufactured by Japan Polyethylene Corporation (MFR 1.0 g / 10 min, density 0.906 g / cm ³ )
(3) Component (C): As the high-pressure method low-density polyethylene component (C), the following commercially available resin was used. It is shown in Table 1.
C-1: Novatec LD LM360 manufactured by Japan Polyethylene Corporation (MFR 0.9 g / 10 min, density 0.928 g / cm ³ )

[Example 1]
An ethylene resin layer I containing 90% by weight of (A-1) and 10% by weight of (C-1) was used in the first layer, and 9% by weight of (A-1) and (B) were used in the second layer. -1) Ethylene resin layer II containing 81% by weight and (C-1) 10% by weight was used, and (A-1) 49.5% by weight and (B-1) 40.5 were used for the third layer. An ethylene resin layer III composed of% by weight and 10% by weight of (C-1) was used.
The resin materials of each of these layers were set in the above-mentioned three-kind three-layer water-cooled inflation molding machine manufactured by PLACO Co., Ltd., and water-cooled inflation molding was performed under the above conditions to obtain a laminate having a thickness of 250 μm, which was evaluated. The results are shown in Table 2.

[Example 2]
Same as in Example 1 except that the ethylene resin layer II containing (A-1) 18% by weight, (B-1) 72% by weight, and (C-1) 10% by weight was used for the second layer. A laminate was obtained and evaluated. The results are shown in Table 2.

[Example 3]
Same as in Example 1 except that the ethylene resin layer II containing (A-1) 27% by weight, (B-1) 63% by weight, and (C-1) 10% by weight was used for the second layer. A laminate was obtained and evaluated. The results are shown in Table 2.

[Comparative Example 1]
An ethylene resin layer I containing 90% by weight of (A-2) and 10% by weight of (C-1) was used as the first layer, and 49.5% by weight of (A-2) was used as the third layer. A laminate was obtained and evaluated in the same manner as in Example 1 except that it was used for (B-1) 40.5% by weight and (C-1) 10% by weight. The results are shown in Table 2.
In this case, the GLOSS before the heat-pressurization sterilization treatment and after the heat-pressure sterilization treatment becomes low, and the optical characteristics deteriorate.

[Comparative Example 2]
An ethylene resin layer I containing 90% by weight of (A-2) and 10% by weight of (C-1) was used as the first layer, and 49.5% by weight of (A-2) was used as the third layer. A laminate was obtained in the same manner as in Example 2 except that it was used for (B-1) 40.5% by weight and (C-1) 10% by weight, and evaluated. The results are shown in Table 2.
In this case, the GLOSS before the heat-pressurization sterilization treatment and after the heat-pressure sterilization treatment becomes low, and the optical characteristics deteriorate.

[Comparative Example 3]
An ethylene resin layer I containing 90% by weight of (A-2) and 10% by weight of (C-1) was used as the first layer, and 49.5% by weight of (A-2) was used as the third layer. A laminate was obtained and evaluated in the same manner as in Example 3 except that it was used for (B-1) 40.5% by weight and (C-1) 10% by weight. The results are shown in Table 2.
In this case, the GLOSS before the heat-pressurization sterilization treatment and after the heat-pressure sterilization treatment becomes low, and the optical characteristics deteriorate.

[Comparative Example 4]
An ethylene resin layer I containing 100% by weight of (A-2) was used for the first layer, and 90% by weight of (B-1), 10% by weight of (C-1), and a third layer were used for the second layer. For the layer, (A-2) 100% by weight of ethylene-based resin layer III was used.
The resin materials of each of these layers were set in the above-mentioned three-kind three-layer water-cooled inflation molding machine manufactured by PLACO Co., Ltd., and water-cooled inflation molding was performed under the above conditions to obtain a laminate having a thickness of 250 μm, which was evaluated. The results are shown in Table 2. Only the film was heat-pressurized and sterilized at 115 ° C.
In this case, the GLOSS before the heat-pressurization sterilization treatment and after the heat-pressure sterilization treatment becomes low, and the optical characteristics deteriorate.

The medical bag made of the laminate of the present invention is excellent in hygiene, heat resistance, transparency, impact resistance, etc., and therefore can be particularly suitably used for infusion preparations and the like.

Claims (3)

A medical bag composed of at least a first layer, a second layer, and a third layer laminated in this order, the first layer being an outer layer, and the third layer being an inner layer.
The ratio of the following component (A) contained in all of the first layer, the second layer, and the third layer and contained in each resin layer of the component (A) is
The relationship of the first layer> the third layer> the second layer is satisfied, and the ratio of the component (A) of the first layer-the ratio of the component (A) of the third layer is 20% by weight or more and 80% by weight or less.
Component (A): Copolymer of ethylene having the following properties (Ai) and (Aii) and α-olefin having 6 carbon atoms (Ai) Melt flow rate (190 ° C., 21.18N) Load) is 0.1 to 4.5 g / 10 minutes (A-iii) Density is 0.93 3 to 0.9 45 g / cm ³
The first layer is composed of an ethylene resin layer I containing 70 to 99% by weight of the component (A) and 1 to 30% by weight of the following component (C), and the second layer is the component (A) 1 to 20. It is composed of an ethylene resin layer II containing 70% by weight, the following component (B) 70 to 98% by weight, and the following component (C) 1 to 20% by weight, and the third layer is 40 to 60% by weight of the component (A). , 40 to 60% by weight of the following component (B) and 1 to 30% by weight of the following component (C) (however, the sum of the blending amounts of the component (A), the component (B) and the component (C). There is a 100% by weight.) ethylene resin layer III Tona is, medical bag, wherein the total thickness of the laminate is 100～700Myuemu.
Component (B): Copolymer (B-i) melt flow of ethylene and α-olefin having 6 carbon atoms produced using a metallocene catalyst having the following characteristics (B-i) to (B-iv). The rate (190 ° C., 21.18N load) is 0. 5 to 10 g / 10 minutes (B-ii) Density is 0. 900 to 0. 920 g / cm ³
(B-iii) α-olefin content is 5-40% by weight
(B-iv) The ratio (Mz / Mn) of the Z average molecular weight (Mz) to the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 8.0 or less. Component (C): The following (C) High-pressure low-density polyethylene (C-i) melt flow rate (190 ° C., 21.18 N load) having the characteristics of -i) to (C-ii) is 0.1 to 5 g / 10 minutes (C-ii) density. Is 0.915 to 0.935 g / cm ³ The first layer is composed of an ethylene resin layer I containing 80 to 95% by weight of the component (A) and 5 to 20% by weight of the component (C), and the second layer is 1 to 20% by weight of the component (A). The third layer is composed of an ethylene resin layer II containing 70 to 98% by weight of the component (B) and 1 to 20% by weight of the component (C), and the third layer is 40 to 60% by weight of the component (A). B) contains 40 to 60% by weight and component (C) 1 to 30% by weight (however, the sum of the blending amounts of the component (A), the component (B) and the component (C) is 100% by weight. There is.) The medical bag according to claim 1, which comprises an ethylene-based resin layer III. The medical bag according to claim 1 or 2 , wherein the third layers of the laminated body face each other and are heat-sealed in a bag shape.