阅读说明：本技术 聚乙烯树脂组合物、层叠体及医疗容器 (Polyethylene resin composition, laminate, and medical container ) 是由 中尾英誉 茂吕义幸 于 2019-09-06 设计创作，主要内容包括：本发明提供一种耐热性、柔软性、阻隔性及清洁性(低微粒性)优异、在121℃下的灭菌处理后也不会变形、保持高透明性、并且在水冷吹塑成形中的加工性优异的聚乙烯系树脂组合物及使用了该聚乙烯系树脂组合物的医疗容器。使用一种聚乙烯树脂组合物,其包含：具有特定的物性的直链状低密度聚乙烯(A)50～89重量份、高密度聚乙烯(B)10～40重量份、高压法低密度聚乙烯(C)1～20重量份((A)、(B)、(C)的合计为100重量份),且MFR满足3.0～9.0g/10min。(The invention provides a polyethylene resin composition which has excellent heat resistance, flexibility, barrier property and cleaning property (low particle property), does not deform after sterilization treatment at 121 ℃, keeps high transparency and has excellent processability in water-cooling blow molding, and a medical container using the polyethylene resin composition. A polyethylene resin composition is used, which comprises: 50 to 89 parts by weight of linear low-density polyethylene (A), 10 to 40 parts by weight of high-density polyethylene (B) and 1 to 20 parts by weight of high-pressure low-density polyethylene (C) (the total of (A), (B) and (C) being 100 parts by weight), each having specific physical properties, and having an MFR of 3.0 to 9.0g/10 min.)

1. A polyethylene resin composition comprising: 50 to 89 parts by weight of a linear low-density polyethylene (A) satisfying the following characteristics (a) to (C), 10 to 40 parts by weight of a high-density polyethylene (B) satisfying the following characteristics (d) to (f), and 1 to 20 parts by weight of a high-pressure low-density polyethylene (C) satisfying the following characteristics (g) to (i), wherein the total of (A), (B), and (C) is 100 parts by weight, and the polyethylene resin composition satisfies the following characteristic (j),

(a) the density is 890-920 kg/m³，

(b) MFR of 3.0 to 15g/10min,

(c) a ratio (Mw/Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) of 2.0 to 3.0,

(d) the density of the coating is 935 to 970kg/m³，

(e) MFR of 3.0 to 15g/10min,

(f) a ratio (Mw/Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) of 2.0 to 3.0,

(g) the density is 910 to 930kg/m³，

(h) MFR of 0.1 to 1.0g/10min,

(i) a melt tension of 200 to 400mN,

(j) the MFR is 3.0 to 9.0g/10 min.

2. A laminate comprising at least 3 layers including an A layer, a B layer and a C layer in this order,

the layer B is made of the polyethylene resin composition according to claim 1, and the layers A and C are made of a thermoplastic resin.

3. The laminate according to claim 1 or 2,

the thermoplastic resin of the layers a and C is a resin composition containing polyethylene.

4. The laminate according to claim 2 or 3, which has a light transmittance of 70% or more after sterilization at 121 ℃.

5. A medical container made from the laminate of any one of claims 2 to 4.

6. A medical container is provided with a storage part for storing a medical liquid,

at least the housing is made of the laminate according to any one of claims 2 to 4.

7. The medical container according to claim 5 or 6, wherein the light transmittance after a sterilization treatment at 121 ℃ for 20 minutes is 70% or more.

Technical Field

The present invention relates to a polyethylene resin composition, and a laminate and a medical container each using the polyethylene resin composition. More specifically, the present invention relates to a resin composition having excellent extrusion characteristics and excellent molding stability during water-cooled blow molding. The present invention also relates to a laminate formed by molding the resin composition, which is suitably used for a medical container such as an infusion bag filled with a drug solution, blood, or the like, and a medical container using the laminate.

Background

Medical containers filled with medical liquids, blood, and the like are required to have the following characteristics: the coating film is used for confirming the mixing of foreign matters, the transparency of change caused by the mixing of medicaments, the flexibility for easily discharging the liquid medicine, the gas barrier property for inhibiting the liquid medicine and the like from being changed and the quality from being reduced due to the permeation of water vapor and oxygen into the container, and the reduction of the dissolution of particles from the container (low particle property). In addition, the products filled with the contents in these containers are generally subjected to a heat sterilization treatment. In particular, in the case of infusion preparations to be administered directly to the blood, the maintenance of sterile conditions is strictly required, and therefore, in recent years, high-temperature sterilization at 121 ℃ has become a global standard, and heat resistance capable of withstanding sterilization treatment at 121 ℃ is strongly required.

Conventionally, as a medical container satisfying such performance, a glass container has been used, but since there are problems such as breakage of the container due to impact or dropping, contamination due to intrusion of external air into the container when dispensing a medical liquid, and the like, a plastic container which is excellent in impact resistance, flexible, and easily discharges a content liquid has been used. As the plastic container, a polyethylene resin such as a soft vinyl chloride resin, an ethylene-vinyl acetate copolymer resin, a polypropylene resin, and a high-pressure low-density polyethylene, a linear low-density polyethylene, and a high-density polyethylene can be used. However, the soft vinyl chloride resin has a sanitary problem such as dissolution of the plasticizer into the chemical solution, and the ethylene-vinyl acetate copolymer resin has poor heat resistance. Polypropylene is widely used as a material for containers satisfying the above transparency and heat resistance, but polypropylene is inherently susceptible to oxidative deterioration due to repeated presence of tertiary carbon, and therefore, an antioxidant must be added. In recent years, because of the increasing demand for safety, particularly in containers for medical drug solutions, a clean material without additives is preferred. Therefore, a new medical container which uses a material without an additive in place of polypropylene and has both transparency and heat resistance is desired. Further, there are problems that when the density is decreased to satisfy transparency and flexibility, the heat resistance is decreased, and when the density is increased to satisfy heat resistance, the transparency and flexibility are decreased in the polyethylene resin.

In recent years, linear polyethylene produced by a single-site catalyst and having excellent transparency has been developed, and a method for solving the above problem by laminating films using the linear polyethylene as a raw material has been proposed (see patent documents 1 to 3). However, these laminates are also insufficient in transparency, and the impact strength of the heat-sealed portion of the container formed by molding is also insufficient, and improvement is desired.

Under such circumstances, in order to produce a polyethylene container having both transparency and heat resistance, various materials such as a resin composition containing polyethylene as a main component, a multilayer container, and a polyethylene resin having specific physical properties have been proposed (for example, see patent documents 4 to 7). The present inventors have also found that a medical container having excellent transparency, heat resistance and cleanability can be provided by using a polyethylene resin composition containing a specific amount of a polyethylene resin having specific physical properties (see, for example, patent document 8).

However, when a worker who uses polypropylene wants to change the material to a polyethylene resin as described above in order to improve the cleanability, the molding may be difficult because of problems such as a high resin pressure due to a narrow flow path inside a mold of a molding machine designed for polypropylene, or uneven film thickness in the width direction due to a disturbed flow rate balance among the parts. When the viscosity of the polyethylene resin is lowered in order to lower the resin pressure, the melt tension is lowered, and there is a problem that the variation of bubbles becomes large and the molding stability is lowered such as occurrence of draw resonance. Therefore, it is desired to develop a clean polyethylene resin which has heat resistance and transparency necessary for medical containers and can be stably produced even with a molding machine for polypropylene.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 8-309939

Patent document 2: japanese laid-open patent publication No. 7-125738

Patent document 3: japanese laid-open patent publication No. 8-244791

Patent document 4: japanese laid-open patent publication No. 2002-265705

Patent document 5: japanese patent laid-open publication No. 2005-7888

Patent document 6: japanese patent laid-open publication No. 2015-42557

Patent document 7: japanese patent laid-open No. 2008-18063

Patent document 8: japanese patent laid-open publication No. 2015-74744

Disclosure of Invention

Problems to be solved by the invention

An object of the present invention is to provide a polyethylene resin composition which is excellent in heat resistance, flexibility, barrier properties and cleanability (low particle size properties) and which is difficult to satisfy the requirements of conventional resins for medical containers, does not deform even after sterilization treatment at 121 ℃, retains high transparency, and is excellent in processability in water-cooling blow molding, and a medical container using the polyethylene resin composition.

Means for solving the problems

The present inventors have conducted extensive studies and, as a result, have found that the above problems can be solved by using a resin composition containing a specific amount of a polyethylene resin having specific physical properties, and have completed the present invention.

That is, the present invention includes the following [1] to [7 ].

[1] A polyethylene resin composition for medical containers, comprising: 50 to 89 parts by weight of a linear low-density polyethylene (A) satisfying the following characteristics (a) to (C), 10 to 40 parts by weight of a high-density polyethylene (B) satisfying the following characteristics (d) to (f), and 1 to 20 parts by weight of a high-pressure low-density polyethylene (C) satisfying the following characteristics (g) to (i), wherein the total of (A), (B) and (C) is 100 parts by weight, and the polyethylene resin composition for medical containers satisfies the following characteristic (j),

(a) the density is 890-920 kg/m³，

(b) A melt flow rate (hereinafter referred to as MFR) measured at 190 ℃ under a load of 21.18N in accordance with JIS K6922-1 of 3.0 to 15g/10min,

(c) a ratio (Mw/Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) of 2.0 to 3.0,

(d) the density of the coating is 935 to 970kg/m³，

(e) MFR of 3.0 to 15g/10min,

(f) a ratio (Mw/Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) of 2.0 to 3.0,

(g) the density is 910 to 930kg/m³，

(h) MFR of 0.1 to 1.0g/10min,

(i) a melt tension of 200 to 400mN,

(j) the MFR is 3.0 to 9.0g/10 min.

[2] A laminate comprising at least 3 layers including an A layer, a B layer and a C layer in this order,

the layer B is made of the polyethylene resin composition according to [1], and the layers A and C are made of a thermoplastic resin.

[3] The laminate according to the above [1] or [2], wherein,

the thermoplastic resin of the layers a and C is a resin composition containing polyethylene.

[4] The laminate according to the above [2] or [3], which has a light transmittance of 70% or more after sterilization at 121 ℃.

[5] A medical container made of the laminate according to any one of [2] to [4 ].

[6] A medical container is provided with a storage part for storing a medical liquid,

at least the housing section is made of the laminate according to any one of [2] to [4 ].

[7] The medical container according to the above [5] or [6], which has a light transmittance of 70% or more after being sterilized at 121 ℃ for 20 minutes.

The polyethylene resin of the present invention, a resin composition containing the polyethylene resin, a laminate of the present invention, and a medical container made of the laminate will be described below.

(1) Straight chain low density polyethylene (A)

The linear low-density polyethylene (a) used in the present invention is a copolymer of ethylene and an α -olefin.

The linear low-density polyethylene (A) of the present invention has a melt flow rate of 3.0 to 15g/10min, preferably 3.0 to 10g/10 min, and more preferably 4.0 to 7.0g/10 min, as measured at 190 ℃ under a load of 21.18N in accordance with JIS K6922-1. If the MFR is less than 3.0g/10 min, the load on the extruder becomes large during molding, and thickness unevenness occurs in the width direction during molding, which is not preferable. Further, an MFR of more than 15g/10min is not preferred because the molding stability is lowered.

The linear low-density polyethylene (A) of the present invention has a density of 890 to 920kg/m in accordance with JIS K6922-1³Preferably 900 to 910kg/m³. The density is less than 890kg/m³In the case of the conventional method, the heat resistance is insufficient, such as deformation of the container due to the sterilization treatment at 121 ℃ and exceeds 920kg/m³In the case, transparency and flexibility are reduced, which is not preferable.

The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the linear low-density polyethylene (A) of the present invention is 2.0 to 3.0. When the Mw/Mn is 3.0 or less, the resulting laminate is preferably reduced in transparency and high in strength when subjected to a sterilization treatment at 121 ℃. When Mw/Mn is 2.0 or more, the extrusion load during molding can be suppressed, and therefore, this is preferable.

The linear low-density polyethylene (a) of the present invention can be produced as follows: for example, the copolymer is produced by copolymerizing ethylene and α -olefin using a metallocene catalyst comprising an organic transition metal compound containing a cyclopentadiene derivative and a compound and/or an organometallic compound which reacts with the organic transition metal compound to form an ionic complex, by a production method such as a high pressure method, a solution method, a gas phase method, or the like, using the method described in japanese patent application laid-open No. 2009-275059, japanese patent application laid-open No. 2013-81494, or the like.

The alpha-olefin is generally referred to as an alpha-olefin, and is preferably an alpha-olefin having 3 to 12 carbon atoms such as propylene, butene-1, hexene-1, octene-1, 4-methyl-1-pentene, or the like. As the copolymer of ethylene and α -olefin, for example, there can be mentioned: ethylene/hexene-1 copolymers, ethylene/butene-1 copolymers, ethylene/octene-1 copolymers, and the like.

(2) High density polyethylene (B)

The high-density polyethylene (B) used in the present invention is an ethylene homopolymer or a copolymer of ethylene and an α -olefin.

The high-density polyethylene (B) of the present invention has an MFR of 3.0 to 15g/10min, preferably 3.0 to 10g/10 min, and more preferably 4.0 to 6.0g/10 min, as measured at 190 ℃ under a load of 21.18N in accordance with JIS K6922-1. If the MFR is less than 3.0g/10 min, the load on the extruder becomes large during molding, and thickness unevenness occurs in the width direction during molding, which is not preferable. Further, an MFR of more than 15g/10min is not preferable because the melt tension becomes small and the molding stability is lowered.

The high-density polyethylene (B) has a density of 935 to 970kg/m in accordance with JIS K6922-1³Preferably 950 to 960kg/m³. If the density is less than 935kg/m³When the heat resistance is insufficient, such as deformation of the container due to the 121 ℃ sterilization treatment, the heat resistance exceeds 970kg/m³In the case, transparency and flexibility are reduced, which is not preferable.

The high-density polyethylene (B) of the present invention has a ratio (Mw/Mn) of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of 2.0 to 3.0. When the Mw/Mn is 3.0 or less, the resulting laminate is preferably reduced in transparency when subjected to a sterilization treatment at 121 ℃. When Mw/Mn is 2.0 or more, the extrusion load during molding can be suppressed, and therefore, this is preferable.

The high-density polyethylene (B) of the present invention can be produced as follows: for example, the catalyst is produced by homopolymerizing ethylene or copolymerizing ethylene and an α -olefin using a metallocene catalyst comprising an organic transition metal compound containing a cyclopentadiene derivative and a compound and/or an organometallic compound which reacts with the organic transition metal compound to form an ionic complex, by a production method such as a slurry method, a solution method, a gas phase method, or the like, by the methods described in japanese patent application laid-open No. 2009-275059, japanese patent application laid-open No. 2013-81494, or the like.

The alpha-olefin is generally referred to as an alpha-olefin, and is preferably an alpha-olefin having 3 to 12 carbon atoms such as propylene, butene-1, hexene-1, octene-1, 4-methyl-1-pentene, or the like. As the copolymer of ethylene and α -olefin, for example, there can be mentioned: ethylene/hexene-1 copolymers, ethylene/butene-1 copolymers, ethylene/octene-1 copolymers, and the like.

(3) High pressure low density polyethylene (C)

The high-pressure low-density polyethylene (C) of the present invention has a melt flow rate (hereinafter referred to as MFR) of 0.1 to 1.0g/10min, preferably 0.1 to 0.5g/10 min, and more preferably 0.2 to 0.4g/10 min, as measured at 190 ℃ under a load of 21.18N in accordance with JIS K6922-1. When the MFR is less than 0.1g/10 min, the load on the extruder becomes large during molding and the viscosity difference from other raw materials becomes too large, resulting in shrinkage, which is not preferable. Further, an MFR of more than 1.0g/10min is not preferred because the molding stability is lowered.

The density of the high-pressure low-density polyethylene (C) according to JIS K6922-1 is 910 to 930kg/m³Preferably 915-925 kg/m³More preferably 918 to 922kg/m³. The density is less than 910kg/m³In the case of the conventional method, the heat resistance is insufficient, such as deformation of the container due to the sterilization treatment at 121 ℃ and exceeds 930kg/m³In the case, transparency and flexibility are reduced, which is not preferable.

The melt tension of the high-pressure low-density polyethylene (C) is 200 to 400mN, preferably 220 to 350mN, and more preferably 250 to 300 mN. When the melt tension is less than 200mN, the molding stability is lowered, which is not preferable. When the melt tension exceeds 400mN, the drawing speed is increased, which is not preferable because the film is broken.

The high-pressure low-density polyethylene (C) of the present invention can be obtained as a commercially available product, and examples thereof include Petrocene 172 (trade name) manufactured by Tosoh corporation.

(4) Polyethylene resin composition

The polyethylene resin composition according to one embodiment of the present invention can be obtained as follows: the polyethylene composition can be obtained by a conventionally known method, for example, a method of mixing the linear low-density polyethylene (a), the high-density polyethylene (B), and the high-pressure low-density polyethylene (C) using a henschel mixer, a V-type mixer, a ribbon mixer, a drum mixer, or the like, or a method of melt-kneading the mixture obtained by such a method using a single-screw extruder, a twin-screw extruder, a kneader, an internal mixer, or the like, followed by granulation.

The blending ratio of the linear low-density polyethylene (A), the high-density polyethylene (B) and the high-pressure low-density polyethylene (C) in the resin composition of the present invention is 50 to 89 parts by weight, preferably 60 to 80 parts by weight, more preferably 65 to 75 parts by weight of the linear low-density polyethylene (A), 10 to 40 parts by weight, preferably 15 to 35 parts by weight, more preferably 15 to 30 parts by weight of the high-density polyethylene (B), 1 to 20 parts by weight, preferably 2 to 15 parts by weight, more preferably 3 to 10 parts by weight of the high-pressure low-density polyethylene (C). (A) The sum of (A), (B) and (C) being 100 parts by weight.

When the linear low-density polyethylene (a) is less than 50 parts by weight, the resulting laminate is undesirably low in transparency, flexibility and strength. When the linear low-density polyethylene (a) exceeds 89 parts by weight, the molding stability is lowered, and the heat resistance of the resulting laminate is lowered, which is not preferable.

When the amount of the high-density polyethylene (B) is less than 10 parts by weight, the heat resistance of the resulting laminate is lowered, and deformation of the container and lowering of transparency occur after the sterilization treatment at 121 ℃. When the amount of the high-density polyethylene (B) is more than 40 parts by weight, the flexibility, transparency and strength of the resulting laminate are undesirably reduced.

If the low-density polyethylene (C) is less than 1 part by weight, the molding stability at the time of water-cooling blow molding is lowered, and a laminate cannot be stably produced, which is not preferable. When the amount of the low-density polyethylene (C) is more than 20 parts by weight, the transparency, heat resistance and strength of the resulting laminate are undesirably lowered.

The resin composition of the present invention has an MFR of 3.0 to 9.0g/10min and a density of 910 to 925kg/m³In the range of (1), the molding stability is good, and the transparency after the sterilization treatment at 121 ℃ is particularly excellent, so that the MFR is more preferably 3.0 to 5.0g/10min, and the density is more preferably 910 to 920kg/m³In the range of (1). When the MFR is less than 3.0, the extrusion characteristics are undesirably reduced, and when the MFR exceeds 9.0, the molding stability and strength are undesirably reduced.

The polyethylene resin composition of the present invention may be appropriately blended with commonly used known additives such as an antioxidant, an antistatic agent, a lubricant, an anti-blocking agent, an antifogging agent, an organic or inorganic pigment, an ultraviolet absorber, a dispersant and the like as needed within a range that does not significantly impair the effects of the present invention. The method of blending the above-mentioned additives in the resin composition of the present invention is not particularly limited, and examples thereof include a method of directly adding the additives in a granulation step after polymerization or a method of preparing a master batch at a high concentration in advance and dry-blending the master batch at the time of molding.

The polyethylene resin composition of the present invention may contain other thermoplastic resins such as polypropylene, ethylene-propylene copolymer rubber, and poly-1-butene, within a range not impairing the effects of the present invention.

(5) Laminated body

The laminate according to one embodiment of the present invention is a laminate comprising at least 3 layers including an a layer, a B layer and a C layer in this order, wherein the B layer is made of the following polyethylene resin composition, and the a layer and the C layer are made of a thermoplastic resin.

A polyethylene resin composition comprising: 50 to 89 parts by weight of a linear low-density polyethylene (A) satisfying the following characteristics (a) to (C), 10 to 40 parts by weight of a high-density polyethylene (B) satisfying the following characteristics (d) to (f), and 1 to 20 parts by weight of a high-pressure low-density polyethylene (C) satisfying the following characteristics (g) to (i), wherein the total of (A), (B) and (C) is 100 parts by weight, and the polyethylene resin composition satisfies the following characteristic (j),

(a) the density is 890-920 kg/m³，

(b) MFR of 3.0 to 15g/10min,

(c) a ratio (Mw/Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) of 2.0 to 3.0,

(d) the density of the coating is 935 to 970kg/m³，

(e) MFR of 3.0 to 15g/10min,

(f) a ratio (Mw/Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) of 2.0 to 3.0,

(g) the density is 910 to 930kg/m³，

(h) MFR of 0.1 to 1.0g/10min,

(i) a melt tension of 200 to 400mN,

(j) the MFR is 3.0 to 9.0g/10 min.

The thermoplastic resin used for the layers a and C of the laminate of the present invention is not particularly limited, and a resin having an excellent balance between transparency and heat resistance is preferably used. For example, a resin composition containing polyethylene is exemplified, and from the viewpoint of hygiene, transparency and heat resistance, Niporon-P FY13, Niporon-P FY11, manufactured by Tosoh corporation (trade name), and the like are preferable as polyethylene. In addition, a resin other than polyethylene such as polypropylene may be used for the a layer or the C layer within a range not impairing the effects of the present invention.

The laminate of the present invention is not particularly limited as long as it has an a layer, a B layer, and a C layer in this order (the C layer is a heat seal layer). The number of layers is most preferably three layers consisting of the above-described a layer/B layer/C layer, but the present invention is not limited thereto, and a layer structure of a layer/B layer/center layer/B layer/C layer, which is a further layer, among the B layers of the a layer/B layer/C layer, may be provided, or other layers may be appropriately provided between the a layer and the B layer, or between the B layer and the C layer, as necessary. Examples of such other layers include an adhesive layer, a gas barrier layer, and an ultraviolet absorbing layer. For example, a five-layer structure of a layer a, a gas barrier layer, a layer B, an adhesive layer, and a layer C may be adopted. Further, a new layer may be provided further outside the C layer. Note that the symbol/symbol between layers indicates adjacent layers.

Further, examples of the adhesive constituting the adhesive layer include: and adhesive resins such as polyurethane adhesives, vinyl acetate adhesives, hot melt adhesives, maleic anhydride-modified polyolefins, and ionomer resins. When the layer structure contains an adhesive layer, the layers may be laminated by extruding necessary constituent layers such as an outer layer, an intermediate layer, and an inner layer together with the adhesive.

The overall thickness of the laminate in the present invention is not particularly limited, and may be appropriately determined as needed, and is preferably 0.01 to 1mm, and more preferably 0.1 to 0.5 mm.

The thickness ratio of each layer is not particularly limited, but it is preferable to increase the density of the outer layer or decrease the thickness of the inner layer in order to prevent deformation and fusion due to sterilization treatment, and to increase the transparency, the balance between transparency and heat resistance is better as the thickness of the intermediate layer having a decreased density is increased. As the thickness ratio of each layer, layer a: layer B: the C layer may be about 1 to 30:40 to 98:1 to 30 (wherein the total of the layers is 100).

From the viewpoint of transparency, the laminate of the present invention preferably has a light transmittance of 70% or more after sterilization treatment at 121 ℃ for 20 minutes, that is, after sterilization.

The method for producing the laminate of the present invention is not particularly limited, and examples thereof include: a method of forming a multilayer film or sheet by a water-cooled or air-cooled coextrusion multilayer blow molding method, a coextrusion multilayer T-die method, a dry lamination method, an extrusion lamination method, or the like. Among them, a water-cooled co-extrusion multilayer blow molding method or a co-extrusion multilayer T-die method is preferably used. Particularly, when the water-cooled coextrusion multilayer blow molding method is used, there are many advantages in transparency, hygiene, and the like.

(6) Medical container

A medical container according to an embodiment of the present invention is made of the laminate. The medical container of the present invention is a medical container including a housing portion for housing a medical solution, and at least the housing portion is made of the laminate.

From the viewpoint of transparency, the medical container of the present invention preferably has a light transmittance of 70% or more after being sterilized at 121 ℃ for 20 minutes, that is, after sterilization.

When the laminate is formed into a film by a water-cooled coextrusion multilayer blow molding method, 2 sheets of the obtained film are stacked, and the peripheral portion is heat-sealed, thereby forming a bag-shaped housing portion. The film obtained may be formed into a concave portion of the housing portion by hot plate forming such as vacuum forming or pressure forming, and then the concave portions are overlapped so as to face each other, and the peripheral portion is heat-sealed, thereby forming the housing portion. In this case, the port portion serving as the injection inlet of the chemical solution may be formed by heat-sealing at the same time as the formation of the housing portion, or the housing portion and the port portion may be formed by additional steps.

The use of the polyethylene medical container of the present invention is applicable to all medical uses, and examples thereof include: blood bags, platelet storage bags, infusion (medicinal liquid) bags, medical multi-chamber containers, bags for artificial dialysis, and the like.

ADVANTAGEOUS EFFECTS OF INVENTION

The resin composition of the present invention is excellent in molding stability during water-cooling blow molding, and a laminate formed from the resin composition is excellent in transparency, flexibility, barrier properties, and cleanability (low particle size properties), and can maintain transparency even after sterilization treatment at 121 ℃.

Examples

The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these examples.

A. Resin composition

The properties of the resins used in examples and comparative examples were evaluated by the following methods.

< Density >

The density was measured by a density gradient tube method in accordance with JIS K6922-1.

＜MFR＞

MFR (melt flow Rate) was measured in accordance with JIS K6922-1.

< molecular weight, molecular weight distribution >

The weight average molecular weight (Mw), the number average molecular weight (Mn), the ratio of the weight average molecular weight to the number average molecular weight (Mw/Mn), and the peak molecular weight (Mp) were measured by GPC. The measurement was carried out using a GPC apparatus (trade name: HLC-8121GPC/HT, manufactured by Tosoh corporation) and a column (TSKgelGMHhr-H (20) HT, manufactured by Tosoh corporation), the column temperature was set at 140 ℃ and 1,2, 4-trichlorobenzene was used as an eluent. The measurement sample was adjusted to a concentration of 1.0mg/ml, and 0.3ml was injected for measurement. The calibration curve for molecular weight was calibrated using polystyrene samples of known molecular weight. Further, Mw and Mn were determined as values in terms of linear polyethylene.

< melt tension >

Measurement of melt tension A die having a length of 8mm and a diameter of 2.095mm was attached to a capillary viscometer (trade name Spirograph, manufactured by Toyo Seiki Seisaku-Sho Ltd.) having a cylinder diameter of 9.55mm at an inflow angle of 90 degrees, and the measurement was carried out. The temperature was set to 160 ℃, the piston lowering speed was set to 10 mm/min, the draw ratio was set to 47, and the load (mN) required for drawing was taken as the melt tension. When the maximum draw ratio is less than 47, the melt tension is set to the load (mN) required for drawing at the maximum draw ratio at which the sheet does not break.

(1) Linear low-density polyethylene

LL-1

[ preparation of modified Clay ]

Adding 37% hydrochloric acid 30ml and N, N-dimethyl mountain into 1500ml water106g of amine, preparation of N, N-dimethyl-shanAqueous alkylammonium hydrochloride solution. 300g of montmorillonite (manufactured by Kunimine industry, manufactured by grinding under the trade name Kunipia F with a jet mill) having an average particle diameter of 7.8 μm was added to the hydrochloric acidIn an aqueous salt solution, the reaction was carried out for 6 hours. After the reaction, the reaction solution was filtered, and the obtained filter cake was dried under reduced pressure for 6 hours to obtain 370g of a modified clay compound.

[ preparation of polymerization catalyst ]

In a 20L stainless steel vessel under a nitrogen atmosphere, 3.3L of heptane, 1.13mol (0.9L) of a heptane solution of triethylaluminum per aluminum atom (20 wt% dilution) and 50g of the modified clay compound obtained above were charged and stirred for 1 hour. To this was added diphenylmethylene (4-phenyl-indenyl) (2, 7-di-t-butyl-9-fluorenyl) zirconium dichloride in an amount of 1.25mmol per unit zirconium atom and stirred for 12 hours, and to the resulting suspension was added 5.8L of an aliphatic saturated hydrocarbon solvent (manufactured by gloss petrochemical, trade name IPSolvent2835), thereby preparing a catalyst. (zirconium concentration 0.125mmol/L)

[ production of LL-1 ]

Ethylene and 1-hexene were continuously introduced into a tank-type reactor for high-temperature and high-pressure polymerization, and the total pressure was set to 90MPa, the 1-hexene concentration was set to 18 mol%, and the hydrogen concentration was set to 8 mol%. Then, the reactor was stirred at 1500rpm, the polymerization catalyst obtained above was continuously supplied from the supply port of the reactor, and the polymerization reaction was carried out while maintaining the average temperature at 200 ℃. The MFR of the obtained linear low-density polyethylene LL-1 was 4.0g/10 min, and the density was 910kg/m³. The results of evaluating the basic properties of LL-1 are shown in Table 1.

LL-2

[ preparation of modified Clay ]

A modified clay compound was prepared in the same manner as LL-1.

[ preparation of polymerization catalyst ]

A polymerization catalyst was prepared in the same manner as LL-1.

[ production of LL-2 ]

Ethylene and 1-hexene were continuously introduced into a tank-type reactor for high-temperature and high-pressure polymerization, and the total pressure was set to 90MPa, the 1-hexene concentration was set to 24 mol%, and the hydrogen concentration was set to 6 mol%. The reactor was then stirred at 1500rpmThe polymerization catalyst obtained above was continuously supplied from the supply port of the reactor, and the polymerization reaction was carried out while maintaining the average temperature at 200 ℃. The MFR of the obtained linear low-density polyethylene LL-2 was 5.0g/10min, and the density was 900kg/m³. The results of evaluating the basic properties of LL-2 are shown in Table 1.

LL-3

[ preparation of modified Clay ]

A modified clay compound was prepared in the same manner as LL-1.

[ preparation of polymerization catalyst ]

A polymerization catalyst was prepared in the same manner as LL-1.

[ production of LL-3 ]

Ethylene and 1-hexene were continuously introduced into the reactor using a tank-type reactor for high-temperature and high-pressure polymerization, and the total pressure was set to 90MPa, the 1-hexene concentration was set to 19 mol%, and the hydrogen concentration was set to 12 mol%. Then, the reactor was stirred at 1500rpm, the polymerization catalyst obtained above was continuously supplied from the supply port of the reactor, and the polymerization reaction was carried out while maintaining the average temperature at 200 ℃. The MFR of the obtained linear low-density polyethylene LL-3 was 7.0g/10 min, and the density was 910kg/m³. The results of evaluating the basic properties of LL-3 are shown in Table 1.

LL-4

[ preparation of modified Clay ]

A modified clay compound was prepared in the same manner as LL-1.

[ preparation of polymerization catalyst ]

A polymerization catalyst was prepared in the same manner as LL-1.

[ production of LL-4 ]

Ethylene and 1-hexene were continuously introduced into a tank-type reactor for high-temperature and high-pressure polymerization, and the total pressure was set to 90MPa, the 1-hexene concentration was set to 18 mol%, and the hydrogen concentration was set to 5 mol%. Then, the reactor was stirred at 1500rpm, the polymerization catalyst obtained above was continuously supplied from the supply port of the reactor, and the polymerization reaction was carried out while maintaining the average temperature at 200 ℃. To obtainThe MFR of the linear low-density polyethylene LL-4 was 2.0g/10 min, and the density was 907kg/m³. The results of evaluating the basic characteristics of LL-4 are shown in Table 1.

(2) High density polyethylene

HD-1

[ preparation of modified Clay Compound ]

Adding dioleyl methylamine into a mixed solvent of 3L of deionized water and 3L of ethanol; (C)₁₈H₃₅)₂(CH₃) N532 g and 37% hydrochloric acid 125g, a solution of dioleylmethylamine hydrochloride was prepared. The solution was heated to 45 ℃ and 1000g of synthetic hectorite was added and stirred at 60 ℃ for 1 hour. After the obtained reaction solution was filtered, the solid content was sufficiently washed with water. After drying the solid content, 1180g of the organically modified clay compound was obtained. The water content was 0.8% as measured by an infrared moisture meter. Next, the organically modified clay compound was pulverized by a jet mill so that the average particle diameter became 15 μm.

[ preparation of polymerization catalyst ]

450g of the organically modified clay compound obtained in [ preparation of modified clay compound ] and 1.4kg of hexane were charged into a 5L flask, and then 7.06kg (18 mmol) of bis (indenyl) zirconium dichloride and 1.78kg (1.8 mol) of a 20 wt% hexane solution of triisobutylaluminum were added, heated to 60 ℃ and stirred for 3 hours. Then, the mixture was cooled to 45 ℃ and left to stand for 2 hours, and then the supernatant was removed. Then, 1.78kg (0.09 mol) of a hexane 1 wt% solution of triisobutylaluminum was added, stirred at 45 ℃ for 30 minutes, left to stand for 2 hours, and then the supernatant was removed, and 2 times the above-mentioned operations were performed, 0.45kg (0.45 mol) of a hexane 20 wt% solution of triisobutylaluminum was added, and the mixture was further diluted with hexane so that the total amount became 4.5L, thereby preparing a polymerization catalyst.

[ production of HD-1 ]

Into a polymerization vessel having an internal volume of 300L, 135 kg/hr of hexane, 20.0 kg/hr of ethylene, 15 NL/hr of hydrogen, and [ preparation of polymerization catalyst ]]The polymerization catalyst obtained in the above item, and a 20 wt% hexane solution of triisobutylaluminum as a co-catalyst, so that the polymerization of triisobutylaluminum in a liquidThe concentration was 0.93 mmol/kg hexane. The polymerization temperature was controlled to 85 ℃. The MFR of the obtained high-density polyethylene HD-1 was 5.0g/10min, and the density was 958kg/m³. The evaluation results of the basic characteristics of HD-1 are shown in Table 2.

HD-2

[ preparation of modified Clay ]

The modified clay compound was prepared in the same manner as HD-1.

[ preparation of polymerization catalyst ]

A polymerization catalyst was prepared by the same method as HD-1.

[ production of HD-2 ]

Into a polymerization vessel having an internal volume of 300L, 135 kg/hr of hexane, 20.0 kg/hr of ethylene, 5 NL/hr of hydrogen, and [ preparation of polymerization catalyst ]]The polymerization catalyst obtained in the above item and a 20 wt% hexane solution of triisobutylaluminum as a co-catalyst were added so that the concentration of triisobutylaluminum in the liquid became 0.93 mmol/kg hexane. The polymerization temperature was controlled to 85 ℃. The MFR of the obtained high-density polyethylene HD-2 was 1.0g/10min, and the density was 952kg/m³. The evaluation results of the basic characteristics of HD-2 are shown in Table 2.

(3) Linear low-density polyethylene

LD-1: the following commercial products were used.

Petrocene 172 (trade name; MFR: 0.3g/10 min, density: 920 kg/m), manufactured by Tosoh corporation³) The results of evaluating the basic characteristics of LD-1 are shown in Table 3.

LD-2: the following commercial products were used.

Petrocene 360(MFR 1.6g/10 min, density 919 kg/m) available from Tosoh corporation³) The results of evaluating the basic characteristics of LD-2 are shown in Table 3.

LD-3: the following commercial products were used.

Petrocene 176 (trade name) manufactured by Tosoh corporation (MFR: 1.0g/10min, density: 924 kg/m)³) The results of evaluating the basic characteristics of LD-3 are shown in Table 3.

LD-4: the following commercial products were used.

Tosoh corporationProduct name of Petrocene 173 (MFR: 0.3g/10 min, density: 924 kg/m)³) The results of evaluating the basic characteristics of LD-4 are shown in Table 3.

LD-5: the following commercial products were used.

Petrocene 175K (MFR: 0.6g/10 min, density: 922 kg/m), manufactured by Tosoh corporation³) The results of evaluating the basic characteristics of LD-5 are shown in Table 3.

< resin composition >

The linear low-density polyethylene (a), the high-density polyethylene (B) and the high-pressure low-density polyethylene (C) were dry-blended at the ratios described in examples and comparative examples, and melt-mixed by a 50 mm-diameter single-screw extruder manufactured by PLACO to prepare evaluation resin pellets. The temperature of the drum was set to C1: 180 ℃, C2: 190 ℃, C3: 200 ℃, C4: 200 ℃ and a die head: at 200 ℃.

B. Laminate and sealed container

The laminates and medical containers used in the examples and comparative examples were produced by the following methods and subjected to sterilization treatment.

< production of laminate and medical Container >

A three-layer film having a film width of 135mm and a film thickness of 250 μm was formed by using a three-layer water-cooled blow molding machine (manufactured by PLACO Co.) at a cylinder temperature of 180 ℃, a water tank temperature of 15 ℃ and a drawing speed of 6 m/min. The outer layer and the inner layer were made of Niporon-P FY13(MFR 1.0g/10min, density 950 kg/m) polyethylene (trade name, manufactured by Tosoh corporation)³). The thickness of each layer was measured so that the outer layer and the inner layer became 20 μm and the intermediate layer became 210 μm. Next, a sample having a length of 195mm was cut out of the three-layer film, one end of the sample was heat-sealed to form a bag, and then 300ml of ultrapure water was filled, and a 50ml head space was provided and heat-sealed to prepare a medical container.

< Sterilization treatment >

The medical container was sterilized at 121 ℃ for 20 minutes using a steam sterilization apparatus (manufactured by osaka, japan).

Various properties of the resin compositions, laminates and medical containers used in examples and comparative examples were evaluated by the following methods.

< extrusion Property >

When the resin pressure of the extruder in the intermediate layer during film formation by the three-layer water-cooled blow molding machine was 20MPa or less, the resin composition was evaluated as having good extrusion characteristics.

O: good extrusion Property (resin pressure of 20MPa or less)

X: poor extrusion characteristics (resin pressure exceeding 20MPa)

< stability of Forming >

The stability of the film (air bubbles) when the film was formed by a three-layer water-cooled blow molding machine was visually observed and evaluated.

O: good stability of bubbles

X: large variation of bubbles

< transparency >

A test piece having a width of 10mm X a length of 50mm was cut out from the three-layer film and the sterilized medical container, and the light transmittance at a wavelength of 450nm was measured in pure water using an ultraviolet-visible spectrophotometer (model 220A, manufactured by Hitachi). The medical container having excellent transparency was standardized for the case where the light transmittance of 70% or more was maintained after the sterilization treatment.

< Heat resistance >

Wrinkles and deformation on the film surface and fusion bonding between inner layers after the sterilization treatment were evaluated by visual observation, and the case where no wrinkles and deformation were observed was rated 3, the case where a slight number of wrinkles and deformation were observed was rated 2, and the case where significant wrinkles and deformation were observed was rated 1.

Example 1

Three-layer films were molded by a water-cooled blow molding machine using the resin compositions shown in Table 4, and the molding stability, surface smoothness of the films, and transparency were evaluated. The thickness of the film was set to 250 μm. Then, the obtained film was heat-sealed to prepare a medical container filled with ultrapure water, and high-pressure steam sterilization was performed at 121 ℃ to evaluate the film appearance, transparency, flexibility, moisture permeability, and cleanability after sterilization. The evaluation results are shown in table 4.

Examples 2 to 7 and comparative examples 1 to 10

A three-layer film and a medical container were produced and evaluated in the same manner as in example 1, except that the resin composition used for the intermediate layer was changed as shown in tables 4 and 5. The evaluation results are shown in tables 4 and 5.

TABLE 1

Linear low-density polyethylene	Unit of	LL-1	LL-2	LL-3	LL-4
						MFR	g/10min	4.0	5.0	7.0	2.0
Density of	kg/m3	910	900	910	907
						Mw/Mn	-	2.5	2.5	2.5	2.2

TABLE 2

High density polyethylene	Unit of	HD-1	HD-2
				MFR	g/10min	5.0	1.0
Density of	kg/m3	958	952
				Mw/Mn	-	2.9	2.8

TABLE 3

High pressure process low density polyethylene	Unit of	LD-1	LD-2	LD-3	LD-4	LD-5
							MFR	g/10min	0.3	1.6	1.0	0.3	0.6
Density of	kg/m3	920	919	924	924	922
							Melt tension	mN	255	295	135	210	180

TABLE 4

TABLE 5

The present invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

It is to be noted that the entire contents of the specification, claims, drawings and abstract of japanese patent application No. 2018-170650 filed on 12/9/2018 are incorporated herein as the disclosure of the specification of the present invention.