JP2012085742A - Laminated body for transfusion bag, and transfusion bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated body for transfusion bag which has heat resistance bearable of sterilization at 124°C and is useful for a transfusion bag, and a transfusion bag using the same.SOLUTION: The laminated body includes an outer layer 2, an inner layer 3, and a middle layer 1 disposed therebetween. The outer layer 2 comprises polyethylene resin containing 20-100 mass% of high density polyethylene resin. The inner layer 3 comprises high density polyethylene resin. The middle layer 1 comprises a resin composition prepared by adding a crystal nucleating agent in a mass ratio of 1,000-5,000 ppm to mixed resin of 10-40 mass% of high density polyethylene resin and 90-60 mass% of linear low density polyethylene resin.

Description

  The present invention relates to a laminate for an infusion bag and a ring fluid bag using the same.

In order to prevent infusions from coming into contact with the outside air during hospital administration of the infusion solution, an infusion bag is used instead of a glass bottle that requires a vent needle. A closed system that does not require pressure is used. The infusion bag is a bag-like container composed of a flexible plastic sheet, and as the plastic, polyvinyl chloride, polyethylene, polypropylene, or the like is used.
Various performances are required for the sheets constituting the infusion bag. For example, flexibility to follow the infusion discharge, transparency that allows visual inspection of foreign matter and the amount of infusion remaining, heat resistance for sterilization treatment, impact resistance not to be damaged by logistics, handling, etc., compliance with various laws In particular, compatibility with the 15th revised Japanese Pharmacopoeia is required.
Among the plastics described above, the sheet made of polyvinyl chloride is satisfactory in flexibility, transparency and impact resistance to some extent, but has a problem of poor heat resistance, and there are many additives such as plasticizers, It is inferior in hygiene. Polypropylene sheets are somewhat satisfactory in flexibility, transparency, and impact resistance at room temperature, but have a problem inferior in impact resistance at low temperatures.
A sheet made of polyethylene, particularly a polyethylene having a density of 0.940 g / cm ³ or less, is excellent in flexibility, transparency, impact resistance, particularly impact resistance at low temperatures, and is being used for infusion bags. is there. For example, Patent Document 1 proposes a medical container using a three-layer film having inner and outer layers and an intermediate layer each made of a specific polyethylene resin, and the density of the intermediate layer is 0.930 g / cm. ^Three or less are used.
However, polyethylene has a problem that its melting point is lower than polypropylene and its heat resistance is poor. In an infusion bag, high-pressure steam sterilization is used for sterilization, and at that time, a high temperature of about 121 ° C. is used. Therefore, even at such a temperature, the infusion bag has wrinkles, deformations, and fusion between layers in the infusion bag. Heat resistance that does not cause problems such as wearing is required.
With respect to such a problem, in Patent Document 2, even if it is made of polyethylene, it is resistant to high-pressure steam sterilization at 121 ° C., and as a laminate useful for medical containers and the like, a resin material (A) in which the inner layer contains high-density polyethylene An ethylene / α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms and having a specific physical property (a) to (d) There has been proposed a laminate comprising a resin material (B) mainly composed of resin I and an outer layer comprising a resin material (C) containing high-density polyethylene.

JP 2001-104451 A JP 2003-237002 A

However, in actual high-pressure steam sterilization, it may exceed 121 ° C., for example, increase to 124 ° C., for example, due to overheating at the time of initial temperature increase or temperature adjustment failure. Therefore, practically, infusion bags subjected to high-pressure steam sterilization at 121 ° C. are required to have heat resistance at 124 ° C.
The present invention has been made in view of the above circumstances, and provides a laminate for an infusion bag having heat resistance that can be sterilized at 124 ° C. and useful for an infusion bag, and an infusion bag using the same. With the goal.

The present invention for solving the above problems has the following aspects.
[1] A laminate having an outer layer, an inner layer, and an intermediate layer disposed therebetween,
The outer layer is composed of a polyethylene resin containing 20 to 100% by mass of a high-density polyethylene resin,
The inner layer is composed of a high density polyethylene resin;
The intermediate layer is a resin in which a crystal nucleating agent is added at a mass ratio of 1000 to 5000 ppm with respect to a mixed resin of 10 to 40% by mass of a high density polyethylene resin and 90 to 60% by mass of a linear low density polyethylene resin. A laminate for an infusion bag, characterized by comprising a composition.
[2] The laminate for an infusion bag according to [1], wherein the crystal nucleating agent contains cyclohexanedicarboxylate.
[3] The laminated body for a ring fluid bag according to [1] or [2], wherein the outer layer is composed of a mixed resin of 20 to 40% by mass of a high density polyethylene resin and 80 to 60% by mass of a low density polyethylene resin. .
[4] A bag-shaped bag body formed by heat-sealing the inner layers of the laminate for an infusion bag according to any one of [1] to [3], and attached to a peripheral portion of the bag body. An infusion bag comprising: a port portion that enables communication between the inside and the outside of the bag body.

  ADVANTAGE OF THE INVENTION According to this invention, the laminated body for infusion bags which has the heat resistance which can be sterilized at 124 degreeC, and is useful as an infusion bag, and an infusion bag using the same.

It is a schematic sectional drawing which shows one Embodiment of the laminated body for infusion bags of this invention. 3 is a graph showing a DSC curve of Sample 1 (HDPE) measured in Test Example 1. FIG. 6 is a graph showing a DSC curve of Sample 2 (LLDPE) measured in Test Example 1. 6 is a graph showing a DSC curve of Sample 3 (mixed resin of 20% by mass of HDPE and 80% by mass of LLDPE) measured in Test Example 1; The DSC curves of Sample 1 (HDPE) and Samples 3 to 5 (HDPE and LLDPE mixed resins with HDPE ratios of 20 mass%, 15 mass%, and 10 mass%, respectively) measured in Test Example 1 are shown. It is a graph. It is a graph which shows the DSC curve of the sample 6 (resin composition which added 2500 ppm of crystal nucleating agents with respect to mixed resin of 20 mass% of HDPE and 80 mass% of LLDPE) measured in Test Example 1. It is a schematic top view which shows one Embodiment of the infusion bag of this invention.

<Laminated body for infusion bag>
The laminate for an infusion bag of the present invention (hereinafter sometimes simply referred to as a laminate) is a laminate having an outer layer, an inner layer, and an intermediate layer disposed therebetween.
Among these, an intermediate | middle layer is a layer used as the main layer of the laminated body of this invention. Here, the “main layer” means the thickest layer. An outer layer is a layer used as the outer surface of an infusion bag. An inner layer is a layer used as the inner surface of an infusion bag. The inner layer is a heat-sealable layer. Therefore, the laminate of the present invention can be processed into a bag shape by stacking the inner layer side inward and heat-sealing the peripheral edge.
The laminate of the present invention will be described more specifically with reference to FIG. FIG. 1 is a schematic cross-sectional view of a laminate 10 according to an embodiment of the present invention. The laminate 10 includes an intermediate layer 1, an outer layer 2 laminated on one surface of the intermediate layer 1, and an inner layer 3 laminated on the surface of the intermediate layer 1 opposite to the outer layer 2.

[Intermediate layer 1]
The intermediate layer 1 is composed of 10 to 40% by mass of a high-density polyethylene resin (hereinafter sometimes referred to as “HDPE”) and 90 to 60% by mass of a linear low-density polyethylene resin (hereinafter sometimes referred to as “LLDPE”). It is comprised from the resin composition which added the crystal nucleating agent with the mass ratio of 1000-5000 ppm with respect to the mixed resin. By containing LLDPE at a predetermined ratio, it has flexibility and impact resistance required for an infusion bag. In addition, when HDPE and a crystal nucleating agent are blended in LLDPE, the heat resistance is improved as compared with the case of LLDPE alone. It is also highly transparent.
In the present invention, the “polyethylene resin” includes polyethylene and a copolymer of ethylene and another monomer other than ethylene. Examples of the other monomer include α-olefins having 3 or more carbon atoms and vinyl acetate. The α-olefin is preferably an α-olefin having 3 to 10 carbon atoms, and specific examples include propylene, 1-butene, 1-hexene and the like. When the polyethylene resin is a copolymer of ethylene and vinyl acetate, the proportion of repeating units derived from vinyl acetate is 3% by mass or less of the total of all repeating units.

HDPE is not particularly limited, and known ones can be used. In general, a catalyst is used which is produced by polymerizing a monomer such as ethylene by a low pressure method or an intermediate pressure method. Examples of the catalyst include a Ziegler-Natta catalyst and a metallocene catalyst.
The density of HDPE is at 0.930 g / cm ³ or more, 0.945 g / cm ³ or more. The higher the density, the better the heat resistance. The upper limit of the density of HDPE is not particularly limited, but it is preferably 0.970 g / cm ³ or less in consideration of availability and transparency.

HDPE preferably has a melting point of 128 ° C or higher, more preferably 128 to 135 ° C. Sufficient heat resistance is obtained when the melting point is 128 ° C or higher. Further, when it is 135 ° C. or lower, transparency and uniform mixing with LLDPE are improved.
The melting point of the polyethylene resin is measured by differential scanning calorimetry (DSC) according to JIS K7121. Specifically, DSC results are shown as a DSC curve with the vertical axis representing heat flow and the horizontal axis representing temperature. In the DSC curve, endothermic reactions such as melting of polyethylene resin are peaked. Indicated. Therefore, the position of the peak is the melting peak temperature of the polyethylene resin. When the melting peak temperature is one, the melting peak temperature is the melting point, and when there are a plurality of melting peak temperatures, the lowest temperature among them is the relevant temperature. It is the melting point of the resin.

HDPE has a melt mass flow rate (hereinafter also referred to as “MFR”) of preferably 0.1 to 50 g / 10 minutes, and more preferably 0.3 to 20 g / 10 minutes. When the MFR is 0.1 to 50 g / 10 min, the moldability is good, and the strength when a laminate is obtained is also good.
Furthermore, when the said laminated body is manufactured by the co-extrusion multilayer multilayer film forming method, it is especially preferable that this MFR is 0.3-10 g / 10min. If it is less than 0.3 g / 10 minutes, fluidity is low and excessive torque is required for extrusion, and film formation is difficult. If it exceeds 10 g / 10 minutes, the melt viscosity is too low and uneven thickness such as uneven thickness tends to occur.
When the laminate is produced by a coextrusion multilayer T-die film forming method, the MFR is particularly preferably 0.5 to 20 g / 10 min. If it is less than 0.5 g / 10 minutes, excessive torque is required for extrusion, the speed becomes slow, and the productivity is poor. When it exceeds 20 g / 10 minutes, the neck-in of the film becomes large and uneven thickness or the like is likely to occur.
The MFR is a value measured under conditions of a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K7210.

As LLDPE, it does not specifically limit and a well-known thing can be utilized. LLDPE is usually a copolymer of ethylene and an α-olefin having 3 or more carbon atoms. LLDPE is generally produced by copolymerizing ethylene and an α-olefin having 3 or more carbon atoms using a Ziegler-Natta catalyst, a metallocene catalyst or a single-site catalyst. The LLDPE used in the present invention may be produced using any of Ziegler-Natta catalyst, metallocene catalyst, and single site catalyst.
Since the density of LLDPE is 0.900 to 0.925 g / cm ³ and the transparency becomes high, 0.900 to 0.920 g / cm ³ is preferable.
LLDPE preferably has a melting point of 115 ° C. or higher, and preferably 117 to 125 ° C. Heat resistance improves that melting | fusing point is 115 degreeC or more. Moreover, a softness | flexibility becomes favorable in it being 125 degrees C or less.
LLDPE preferably has an MFR of 0.1 to 50 g / 10 minutes, and more preferably 0.3 to 20 g / 10 minutes. If the MFR is 0.1 to 50 g / 10 min, the moldability is good.
Further, it is preferable that the difference between the MFR of LLDPE and the MFR of HDPE is 2.5 g / 10 min or less. The smaller the difference, the more uniform the mixture and the better the transparency.

The crystal nucleating agent is also called a nucleating agent or a crystallization nucleating agent, and serves as a starting point for crystallization of the thermoplastic resin.
In general, the crystal nucleating agent includes an inorganic crystal nucleating agent and a synthetic organic nucleating agent. Specific examples of inorganic crystal nucleating agents include talc and mica. Specific examples of synthetic organic nucleating agents include cyclohexanedicarboxylic acid salts such as cyclohexanedicarboxylic acid calcium salt and cyclohexanedicarboxylic acid sodium salt; sorbitol nucleating agents such as dibenzylidene sorbitol and bis (p-methylbenzylidene) sorbitol; Amide nucleating agents such as 2,6-naphthalenedicarboxylic acid N, N′-dicyclohexylamide; and the like. Moreover, you may use the crystal nucleating agent composition which mix | blended the additive with the crystal nucleating agent. Examples of additives to be added to the crystal nucleating agent composition include higher fatty acid salts and silicon dioxide.
Among the above, as the crystal nucleating agent, cyclohexanedicarboxylate is particularly preferable because of excellent effects of the present invention.
A commercially available product can be used as the crystal nucleating agent. For example, as the cyclohexanedicarboxylate, a crystallization nucleating agent master batch “Rike Master CN” manufactured by Riken Vitamin Co., Ltd. can be mentioned. As an amide nucleating agent, an amide-based melt-type transparent nucleating agent “Rika Clear PCI” manufactured by Shin Nippon Chemical Co., Ltd. can be used.

In the present invention, the transparency of the intermediate layer 1 to be formed is improved by adding a predetermined amount of a crystal nucleating agent to a mixed resin obtained by mixing HDPE and LLDPE at a predetermined ratio. Moreover, heat resistance is also improved.
One reason for the improvement in transparency is that many small crystals are produced during film formation. That is, if the size of the crystal existing in the intermediate layer 1 is larger than the wavelength of visible light, the visible light is scattered by the crystal, resulting in low transparency. Since it passes through the layer 1, transparency is increased. In the present invention, it is considered that transparency is improved by forming many crystals smaller than 400 nm in the intermediate layer 1. Actually, the haze of the 30 μm thick film formed by adding 2500 ppm of “Rike Master CN-001” as a crystal nucleating agent to the same LLDPE used in Test Example 1 described later by the present inventors is It was 8.2%, which was much improved compared to the 15.4% haze of the same 30 μm film without the addition of the crystal nucleating agent.
The crystal size can be measured by wide angle x-ray scattering.

In addition, in the present invention, the reason why the heat resistance of the intermediate layer 1 is improved is that HDPE and LLDPE form a eutectic, whereby the melting peak temperature is higher than in the case of LLDPE alone, and its crystallization is caused by a crystal nucleating agent. The degree of melting improves and the melting peak temperature further increases.
HDPE and LLDPE form a eutectic. In general, when a polyethylene resin is crystallized, a thin plate-like microcrystal formed by repeated folding of molecular chains, a so-called lamella, is formed, and a laminate of these lamellas grows in a radial direction while twisting to form a spherulite. The lamella made from HDPE is similar to the lamella made from LLDPE without long-chain branching. When growing from lamella to spherulite, HDPE lamella and LLDPE lamella enter each other and become one spherulite. It is thought to make crystals.
Note that no eutectic is formed between HDPE and low-density polyethylene (hereinafter sometimes referred to as “LDPE”). This is presumably because LDPE has a long-chain branched structure, so that its lamellar structure is different from that of HDPE.

Note that when HDPE and LLDPE form a eutectic, the melting peak temperature becomes one, and the melting peak temperature is between the melting peak temperature of HDPE and the melting peak temperature of LLDPE.
For example, the melting peak temperature of HDPE used in Test Example 1 described later was 132.5 ° C., and the melting peak temperatures of LLDPE were 116 ° C. and 121.4 ° C., but HDPE 20 mass% and LLDPE 88 mass % Of the mixed resin (HDPE / LLDPE [20/80]), the melting peak temperature became one peak temperature of 124.4 ° C. This is presumably because a eutectic was formed.
Moreover, the melting peak temperature of the mixed resin varies depending on the mixing ratio of HDPE and LLDPE, and as shown in FIG. 5, the melting peak temperature increases as the mixing ratio of HDPE increases.
When a crystal nucleating agent is added to a mixed resin of HDPE and LLDPE, the crystallinity of the eutectic increases and the melting peak temperature also increases as shown in the results of Test Example 1 described later.

In this invention, the mixed resin used for the resin composition which forms the intermediate | middle layer 1 consists of HDPE10-40 mass% and LLDPE90-60 mass% (the sum total of HDPE and LLDPE is 100 mass%).
The proportion of HDPE in the mixed resin is preferably 10 to 35% by mass.
When the proportion of HDPE is not less than the lower limit of the above range, the eutectic melting peak temperature is also increased, and the heat resistance of the intermediate layer 1 to be formed is improved. On the other hand, when the ratio of HDPE exceeds the upper limit of the above range, the flexibility of the formed intermediate layer 1 is lost and the transparency is also lowered.

  The addition amount of the crystal nucleating agent with respect to the mixed resin is 1000 to 5000 ppm (mixed resin / crystal nucleating agent = 1 / 0.001 to 1 / 0.005) in mass ratio, and preferably 1000 to 3000 ppm. If the addition amount is less than 1000 ppm, the effect of adding the crystal nucleating agent cannot be sufficiently obtained, heat resistance is insufficient, and the appearance after high-pressure steam sterilization becomes poor. Further, the transparency is also insufficient. On the other hand, even if added in excess of 5000 ppm, the crystallinity is saturated and the cost is increased, and the clarity of image clarity, which is one of the light transmission characteristics, is deteriorated, and the transparency may be lowered. There is also.

  In the resin composition, other components than HDPE, LLDPE and crystal nucleating agent may be blended within a range not impairing the effects of the present invention. Examples of the other components include additives such as neutralizing agents and antioxidants. However, since the laminate of the present invention is used for an infusion bag, it is preferable that these additives are not blended in the resin composition.

The resin composition preferably has an MFR of 0.1 to 50 g / 10 minutes, and more preferably 0.3 to 20 g / 10 minutes. If the MFR is 0.1 to 50 g / 10 min, the moldability is good. The MFR of the resin composition can be adjusted by the MFR of HDPE and LLDPE constituting the mixed resin, the mixing ratio thereof, and the like.
The resin composition can be prepared by dry blending each component.

[Outer layer 2]
The outer layer 2 is made of a polyethylene resin containing 20 to 100% by mass of HDPE. Sufficient heat resistance can be obtained by containing 20% by mass or more of HDPE. On the other hand, when the content is less than 20% by mass, there is a possibility that unevenness or the like may occur on the surface when autoclaving is performed.
Examples of the HDPE include the same HDPE as described in the description of the intermediate layer 1.
HDPE used for the outer layer 2 preferably has a melting point of 128 ° C. or higher, more preferably 128 to 135 ° C. The density is at 0.930 g / cm ³ or more, 0.945 g / cm ³ or more. The higher the density, the better the heat resistance. The upper limit of the density of HDPE is not particularly limited, but is preferably 0.970 g / cm ³ or less in consideration of availability, uniformity during mixing, and the like.
The MFR of the HDPE is preferably from 0.1 to 50 g / 10 minutes, more preferably from 0.3 to 20 g / 10 minutes. If the MFR is 0.1 to 50 g / 10 min, the moldability is good.
Further, when the laminate is produced by a co-extrusion method such as a co-extrusion multi-layer inflation film formation method or a co-extrusion multi-layer T-die film formation method, the MFR of the HDPE is the MFR of the resin composition constituting the intermediate layer 1. And the difference is preferably 2.5 g / 10 min or less. The smaller the difference, the better the moldability.

The outer layer 2 may be composed of only HDPE, or may be composed of a mixed resin of HDPE and a polyethylene resin other than HDPE.
Examples of polyethylene resins other than HDPE include LLDPE and LDPE. Among these, LDPE is particularly preferable because it is excellent in blocking prevention effect and the flexibility of the formed outer layer 2 is also excellent.
As the LLDPE, the same LLDPE as mentioned in the description of the intermediate layer 1 can be used.

The LDPE is not particularly limited, and known ones can be used. LDPE has a long-chain branched structure and is generally produced by polymerizing a monomer such as ethylene by a high pressure method using a catalyst. Examples of the catalyst include organic peroxides.
The density of LDPE is 0.915~0.935g / cm ^3, preferably 0.920~0.930g / cm ^3.
LDPE has a melting point of preferably 100 ° C. or higher, and preferably 105 to 118 ° C. When the melting point is 100 ° C. or higher, the heat resistance is good.
The LDPE preferably has an MFR of 0.1 to 50 g / 10 minutes, and more preferably 0.3 to 20 g / 10 minutes. If the MFR is 0.1 to 50 g / 10 min, the moldability is good.
Further, when the laminate is produced by a co-extrusion method such as a co-extrusion multi-layer inflation film forming method or a co-extrusion multi-layer T-die film forming method, the MFR of the LDPE is the MFR of the resin composition constituting the intermediate layer 1. And the difference is preferably 2.5 g / 10 min or less. The smaller the difference, the better the moldability and transparency.

In the mixed resin, the proportion of HDPE is preferably 60% by mass or less, and more preferably 40% by mass or less. When the proportion of HDPE is 60% by mass or less, the transparency is excellent.
As the polyethylene resin constituting the outer layer 2, a mixed resin of 20 to 40% by mass of HDPE and 80 to 60% by mass of LDPE is particularly preferable. The outer layer 2 formed using such a mixed resin has a rough surface to some extent, is less likely to cause blocking, and has good moldability.

  In the polyethylene resin which comprises the outer layer 2, other components other than a polyethylene resin may be mix | blended in the range which does not impair the effect of this invention. Examples of the other components include additives such as a neutralizing agent, an antioxidant, and an antiblocking agent. However, since the laminate of the present invention is used for an infusion bag, it is preferable that these additives are not blended in the polyethylene resin.

[Inner layer 3]
The inner layer 3 is composed of HDPE. Thereby, when heat resistance is favorable and the said laminated body 10 is made into an infusion bag by heat sealing, it can prevent that the inner surfaces of an infusion bag fuse | melt in the area | region which is not heat-sealed.
Examples of the HDPE include the same HDPE as described in the description of the intermediate layer 1.
The HDPE used for the inner layer 3 preferably has a melting point of 128 ° C. or higher, more preferably 128 to 135 ° C. When the melting point is 128 ° C. or higher, the inner surfaces of the infusion bag are not fused to each other even when the high pressure steam sterilization treatment is performed at 124 ° C.
The density of the HDPE is at 0.930 g / cm ³ or more, 0.945 g / cm ³ or more. The higher the density, the better the heat resistance. The upper limit of the density of HDPE is not particularly limited, but 0.970 g / cm ³ or less is preferable in consideration of availability.
The MFR of the HDPE is preferably from 0.1 to 50 g / 10 minutes, more preferably from 0.3 to 20 g / 10 minutes. If the MFR is 0.1 to 50 g / 10 min, the moldability is good.
Further, when the laminate is produced by a co-extrusion method such as a co-extrusion multi-layer inflation film formation method or a co-extrusion multi-layer T-die film formation method, the MFR of the HDPE is the MFR of the resin composition constituting the intermediate layer 1. And the difference is preferably 2.5 g / 10 min or less. The smaller the difference, the more uniformly mixed.

  The HDPE constituting the inner layer 3 may be blended with components other than HDPE as long as the effects of the present invention are not impaired. Examples of the other components include additives such as an antioxidant and a neutralizing agent. However, since the laminate of the present invention is used for an infusion bag, it is preferable that these additives are not blended in the HDPE.

The laminate 10 is a sheet (including a film), and the total thickness of the intermediate layer 1, the outer layer 2 and the inner layer 3 varies depending on the infusion bag manufactured using the laminate, but is usually 50 to 500 μm. And is preferably 100 to 400 μm. The thicker the total thickness, the better the flexibility, strength, etc., and the thinner the total thickness, the better the transparency, flexibility, etc.
Further, the ratio of the thickness of the intermediate layer 1 to the total thickness of the intermediate layer 1, the outer layer 2, and the inner layer 3 is preferably 40 to 90%, and more preferably 70 to 90%. The intermediate layer 1 is a main layer, and mainly contributes to improvement of flexibility and heat resistance of the laminate. If the proportion is less than 40%, the flexibility and heat resistance of the laminate may be lost. If the proportion exceeds 90%, the proportion of the outer layer 2 and the inner layer 3 is relatively low, and the laminate may be formed by coextrusion or the like. When forming a film, stable film formation becomes difficult.
Moreover, 5-30% is preferable and, as for the ratio of the thickness of the outer layer 2 with respect to the total thickness of the intermediate | middle layer 1, the outer layer 2, and the inner layer 3, 5-15% is more preferable. If the proportion of the outer layer 2 is less than 5%, there is a risk of film breakage of the outer layer 2 when forming a laminate by coextrusion or the like, and if it exceeds 30%, the heat resistance as the laminate is reduced. There is a fear.
Moreover, 5-30% is preferable and, as for the ratio of the thickness of the inner layer 3 with respect to the total thickness of the intermediate | middle layer 1, the outer layer 2, and the inner layer 3, 5-15% is more preferable. If the ratio of the inner layer 3 is less than 5%, there is a risk of film breakage of the inner layer 3 when forming a laminate by coextrusion or the like, and if it exceeds 30%, the flexibility as the laminate decreases. There is a fear.

  Although FIG. 1 shows a laminated body 10 having a three-layer structure of an intermediate layer 1, an outer layer 2, and an inner layer 3, the layer structure of the laminated body of the present invention is not limited to this, and the effect of the present invention. In the range which does not impair this, you may have other layers other than the intermediate | middle layer 1, the outer layer 2, and the inner layer 3. FIG.

It does not specifically limit as a manufacturing method of the laminated body of this invention, It can manufacture using a well-known method as a method of manufacturing a well-known multilayer sheet or multilayer film. Specific examples of the production method include a co-extrusion method and an extrusion lamination method. Among these, the coextrusion method is preferable.
Examples of the co-extrusion method include a water-cooled or air-cooled co-extrusion multi-layer inflation film formation method, a co-extrusion multi-layer T-die film formation method, and the like.
In the coextrusion method, the outer layer, the intermediate layer, and the inner layer are coextruded at a time, so that the polyethylene resin constituting the outer layer, the resin composition constituting the intermediate layer, and the MFR of HDPE constituting the inner layer may be substantially the same. preferable.
Specifically, as described in the description of the HDPE of the intermediate layer 1, in the case of the coextrusion multilayer inflation method, each MFR is preferably 0.3 to 10 g / 10 min, and the multilayer coextrusion T In the case of die film formation, the MFR is preferably 0.5 to 20 g / 10 min. Within this range, stable film formation can be achieved.
Furthermore, the difference between the MFR of the resin composition constituting the intermediate layer and the MFR of the polyethylene resin constituting the outer layer is preferably 2.5 g / 10 min or less, and the difference in the resin composition constituting the intermediate layer is The difference between the MFR and the MFR of HDPE constituting the inner layer is preferably 2.5 g / 10 min or less.

The laminated body of the present invention described above has high heat resistance, and an infusion bag manufactured using the laminated body can be subjected to high-pressure steam sterilization treatment reaching 124 ° C. Further, the laminate has the same level of flexibility, transparency and impact resistance as LLDPE.
That is, in the above configuration, the intermediate layer increases the crystallinity of HDPE and LLDPE by the nucleating agent while maintaining the flexibility, transparency, and impact resistance of LLDPE. Also, since HDPE and LLDPE have similar molecular structures, the crystals produced by each make a eutectic as if they were one crystal, and are between the melting peak temperature of LLDPE and the melting peak temperature of HDPE. One melting peak (melting point) is shown. This increases the heat resistance of the intermediate layer. Since the intermediate layer is a main layer of the laminate, the heat resistance of the entire laminate is also improved.
Moreover, in the outer layer, heat resistance sufficient to withstand the sterilization temperature is imparted by containing HDPE in a predetermined amount or more, and when LDPE is mixed, flexibility is improved.
Further, since the inner layer is an HDPE layer, the inner layer surfaces can be heat-sealed to produce a ring solution bag, and the inner layer surfaces can be fused even when the temperature is reduced to 124 ° C. Hard to occur.

<Infusion bag>
The infusion bag of the present invention is manufactured using the laminate of the present invention, and is attached to the peripheral portion of the bag body formed by heat-sealing the inner layers of the laminate. And a port portion that enables communication between the inside and the outside of the bag body.
The infusion bag of the present invention is not particularly limited as long as the bag body is composed of the laminate of the present invention, and the shape and structure thereof are not particularly limited, and may be the same structure as a known infusion bag.
FIG. 7 shows an embodiment of the infusion bag. FIG. 7 is a schematic top view of the infusion bag 20 of the present embodiment.
The infusion bag 20 includes a bag main body 23 composed of a pair of substantially rectangular films 21 and 22 facing each other, a hollow port portion 24 that is open at both ends and allows the inside and the outside of the bag main body 23 to communicate with each other. The films 21 and 22 are each a laminate of the present invention.

A port portion 24 is attached to the peripheral edge at one end in the longitudinal direction of the bag body 23, and the peripheral portions other than the attachment position of the port portion 24 are heat sealed, and the inner layers of the films 21 and 22 are fused together. Yes.
A substantially circular suspension hole 25 is provided on the peripheral edge of the bag body 23 on the side opposite to the mounting position of the port portion 24.
The port portion 24 is attached to the bag body 23 so that one end opens into the bag body 23 and the other end opens outside the bag body 23, and is used as an infusion port and / or a discharge port.
The opening on the outside of the bag body 23 of the port portion 24 is closed with a stopper such as a rubber stopper (not shown) after filling with the infusion solution, and prevents the infusion solution from flowing out of the bag body 23 before use (during transportation / storage). In use, the infusion solution in the bag body 23 can be discharged by connecting a discharging means such as a puncture needle or a dedicated adapter. The surface of the stopper may be covered with a peelable protective film.
The port portion 24 can be attached by sandwiching the port portion 24 between the films 21 and 22 and heat-sealing.
The heat sealing of the peripheral portions of the films 21 and 22 and the attachment of the port portion 24 to the bag body 23 can be performed using a known heat sealing jig, respectively.

The material constituting the port portion 24 is not particularly limited, and known materials can be used. Synthetic resin is generally used as the material. Examples of the synthetic resin include polyolefin resin, polyamide resin, polyester resin, (meth) acrylic resin, vinyl chloride resin, vinylidene chloride resin, polyethersulfone, and ethylene. -Vinyl alcohol copolymer etc. are mentioned. Among these, polyolefin resin is preferable from the viewpoint of excellent hygiene and low cost.
Examples of the polyolefin resin include HDPE, medium density polyethylene, LDPE, LLDPE, polyethylene resins such as ethylene-vinyl acetate copolymer, olefin elastomers such as ethylene-α olefin random copolymer, polypropylene, ethylene-propylene random Examples thereof include polypropylene resins such as copolymers and α-olefin-propylene random copolymers, cyclic polyolefin resins, and mixtures of any two or more thereof.
These synthetic resins may be blended for improving performance, or may be partially crosslinked for the purpose of improving heat resistance.
From the viewpoint of adhering a part of the outer peripheral surface to the inner layer surface of the films 21 and 22 by heat sealing, the port portion 24 is preferably made of a synthetic resin at least at a portion in contact with the films 21 and 22. In consideration, it is particularly preferable that the entire port portion 24 is made of a synthetic resin.
The port portion 24 may have a single layer structure made of a single material, or may have a multilayer structure made of a plurality of synthetic resin layers.
The synthetic resin constituting the port portion 24 is preferably a synthetic resin of the same type as the synthetic resin constituting the inner surface of the films 21 and 22, that is, HDPE, because heat sealing is easy and the adhesive strength is high.
The port portion 24 can be produced by a known molding method such as injection molding.

As mentioned above, although the infusion bag of this invention was shown and demonstrated embodiment, this invention is not limited to this embodiment.
For example, in the above embodiment, only the peripheral portion of the bag body is heat-sealed, and an example in which there is one chamber filled with the infusion solution is shown. However, the infusion solution is a multi-chamber in which the bag body is divided into a plurality of chambers. It may be a bag.

By filling the infusion bag of the present invention with an infusion solution, an infusion bag containing an infusion solution can be obtained.
The infusion is not particularly limited, and any known infusion can be used.
The filling of the infusion solution into the infusion bag is usually performed from the port portion 24. In addition, after the opening of the port portion 24 outside the bag main body 23 is closed, a part of the bag main body 23 is cut to provide an opening communicating with the bag main body 23, and after filling with the infusion solution, the opening is heated. It may be sealed with a seal.
The obtained infusion bag containing infusion may be sterilized. As the sterilization treatment, heat sterilization treatment with high-pressure steam is usually performed. The sterilization is usually about 121 ° C. However, since the infusion bag of the present invention is composed of the laminate of the present invention, sterilization at 124 ° C., for example, is also possible. The sterilization time is usually about 20 to 30 minutes.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited thereto.
<Test Example 1>
In order to evaluate the influence of the composition of the intermediate layer of the laminate on the heat resistance, the following 6 types of samples 1 to 6 were prepared, and the 3 types and 3 layers of downward water-cooled coextrusion inflation film forming machine (hereinafter simply referred to as film forming). A single layer film was produced by the following procedure.
Sample 1: HDPE without additives (melting point: 132 ° C., density: 0.956 g / cm ³ , MFR: 3.5 g / 10 minutes, “Novatech HD” manufactured by Nippon Polyethylene Co., Ltd.).
Sample 2: LLDPE with no additive produced using a metallocene catalyst (melting point 121 ° C., density 0.908 g / cm ³ , MFR 0.9 g / 10 min, “Harmolex LL” manufactured by Nippon Polyethylene Co., Ltd.).
Sample 3: A mixed resin (HDPE / LLDPE [20/80] obtained by dry blending 20 parts by mass of HDPE same as that used in Sample 1 and 80 parts by mass of LLDPE used in Sample 2 ).
Sample 4: A mixed resin (HDPE / LLDPE [15/85] obtained by dry blending 15 parts by mass of HDPE same as that used in Sample 1 and 85 parts by mass of LLDPE same as that used in Sample 2 ).
Sample 5: A mixed resin (HDPE / LLDPE [10/90] obtained by mixing 10 parts by mass of HDPE same as that used in Sample 1 and 90 parts by mass of LLDPE same as that used in Sample 2 by dry blending. ).
Sample 6: 20 parts by mass of HDPE same as that used for the sample 1, 80 parts by mass of LLDPE used for the sample 2, and a master batch “Rike Master CN-002” manufactured by Riken Vitamin Co., Ltd. Resin composition (HDPE / LLDPE [20/80] + obtained by mixing by dry blending so that the acid-based crystal nucleating agent is 0.25 parts by mass (2500 ppm relative to the total of HDPE and LLDPE) (Crystal nucleating agent 2500 ppm).

Any one of the above samples 1 to 6 was put into an extruder for an intermediate layer of a film forming machine to form a film, and a single layer film (225 μm) was prepared. During film formation, the barrel temperature of the intermediate layer extruder was set to 190 ° C.
About the single layer film obtained using each of samples 1-6, the melting peak temperature (melting | fusing point) by DSC and the heat of fusion were measured with the following procedures.
(Measurement of melting peak temperature and heat of fusion)
Using a differential scanning calorimeter “DSC220” manufactured by Seiko Electronics Co., Ltd., measurement was performed under the following measurement conditions.
Measurement conditions: Single layer film 5.3 mg, nitrogen gas 50 mL / min, temperature was increased from 40 to 200 ° C. at a temperature increase rate of 10 ° C./min.
The DSC curves for Sample 1 (HDPE), Sample 2 (LLDP), and Sample 3 (HDPE / LLDPE [20/80]) are shown in FIGS. 2 to 4 respectively, and the DSC curves for Sample 1 and Samples 3 to 5 are collectively shown. As shown in FIG. In addition, FIG. 6 shows a DSC curve of Sample 6 (HDPE / LLDPE [20/80] + crystal nucleating agent 2500 ppm).

As shown in FIGS. 2 to 4, the melting peak temperature of HDPE was 132.5 ° C., and the melting peak temperatures of LLDPE were 116 ° C. and 121.4 ° C. In HDPE / LLDPE [20/80], the melting peak temperature was one of 124.4 ° C. This is probably because a eutectic of HDPE and LLDPE was formed. Thus, since the melting peak temperature of HDPE / LLDPE [20/80] is about 5 ° C. higher than the melting peak temperature of LLDPE, it was confirmed that the heat resistance was improved as compared with LLDPE.
In addition, as shown in FIG. 5, the melting peak temperature of the mixed resin of HDPE and LLDPE varies depending on the mixing ratio of HDPE and LLDPE, and the melting peak temperature increases as the mixing ratio of HDPE increases. That is, the melting peak temperatures of HDPE, HDPE / LLDPE [20/80], HDPE / LLDPE [15/85], HDPE / LLDPE [10/90] are as shown in Table 1 below, and the ratio of HDPE is 5 When the percentage increased, it increased by about 1 ° C.

Table 2 shows melting peak temperatures and heats of fusion (J / g) of Sample 3 (HDPE / LLDPE [20/80]) and Sample 6 (HDPE / LLDPE [20/80] + crystal nucleating agent 2500 ppm).
As shown in FIGS. 4 and 6 and Table 2, the addition of the crystal nucleating agent increases the melting peak temperature by 2.1 ° C., and the ratio of the heat of fusion is 77.1 / 71.7 = 1.075. The heat of fusion was 7.5% higher. Since the heat of fusion is the amount of heat absorbed when the crystal melts, it can be seen that the crystallinity is 7.5% higher than when no crystal nucleating agent is added.
Thus, when a crystal nucleating agent is added to a mixed resin of HDPE and LLDPE, the crystallinity of the eutectic increases and the melting peak temperature also increases.
The single-layer film obtained using Sample 6 corresponds to the intermediate layer in the laminate of the present invention, and exhibits the same behavior when formed into a laminate. Therefore, from the above results, it was shown that the heat resistance as a laminate is improved by forming an intermediate layer from a resin composition in which a crystal nucleating agent is added to a mixed resin of HDPE and LLDPE.

<Example 1>
[1. Creation and evaluation of laminates)
A laminated body having the same configuration as the laminated body 10 shown in FIG. 1 was manufactured by the following procedure using a three-layer, three-layer downward water-cooled coextrusion inflation film forming machine.
30 parts by mass of HDPE used in Test Example 1 and LDPE without additives (melting point: 114 ° C., density: 0.927 g / cm ³ , MFR: 1.1 g / 10 min, “Novatech LD” 70 manufactured by Nippon Polyethylene Co., Ltd. The outer layer mixed resin was prepared by mixing the mass part with dry blend.
The mixed resin for the outer layer is put into the extruder for the outer layer of the film forming machine, the same resin composition as the sample 6 used in Test Example 1 is put into the extruder for the intermediate layer, and the extruder for the inner layer is put into the extruder. The same HDPE as used in Test Example 1 was introduced to form a film, and a laminate (total thickness 250 μm) of outer layer (15 μm) / intermediate layer (225 μm) / inner layer (10 μm) was prepared. During film formation, the barrel temperatures of the outer layer, intermediate layer, and inner layer extruders were set to 190 ° C., respectively.

The following evaluation was performed about the produced laminated body.
(1-1. Evaluation of transparency)
When the appearance of the obtained laminate was visually observed, it was very transparent.
The laminate was cut into a width of 10 mm and a length of 50 mm, and the light transmittance at a wavelength of 450 nm was measured using a “LI-1100 Hitachi Ratio Beam Spectrophotometer” manufactured by Hitachi Science Systems, Ltd. However, the light transmittance was 75%.
From these results, it was confirmed that the laminate had excellent transparency.

(1-2. Evaluation of compatibility with the Japanese Pharmacopoeia)
Conformity test (test items: heavy metal, lead, cadmium, residual residue, eluate) conforming to the plastic drug container test method stipulated in the 15th Amendment Japanese Pharmacopoeia, “Polyethylene or Polypropylene Injection Container” went. The results are shown in Table 3.
From the results in Table 3, it was confirmed that the laminate had almost no eluate and conformed to the 15th revised Japanese Pharmacopoeia standard.

(1-3. Evaluation of heat resistance)
The laminate obtained above was cut into a size of 24 cm × 15 cm, two of them were overlapped so that the inner layer surfaces were in contact with each other, and three of the four sides were heat sealed to form a three-sided bag.
This three-sided bag was filled with 500 mL of distilled water, and 50 mL of head space was provided and sealed. Thereafter, sterilization treatment was performed at 124 ° C. for 30 minutes under a pressure of 0.2 MPa using a hot water stationary high-pressure steam sterilizer. After cooling, the bag was taken out and the appearance was observed.
As a result, the inner surfaces of the bag were not fused to each other, wrinkles were not generated or deformed, and the appearance was the same as before sterilization. From this result, it was confirmed that the laminate had heat resistance to a temperature of 124 ° C.

[2. Preparation and evaluation of infusion bag)
An infusion bag having the same configuration as the infusion bag 20 shown in FIG. 7 was prepared using a dedicated heat seal jig, using the above-described laminate and the HDPE port portion prepared by injection molding. The size of the bag body was 24 cm × 15 cm.
Distilled water (500 mL) was poured into the bag body from the port portion of the infusion bag, a head space (50 mL) was provided, and the port portion was sealed with a rubber plug made of isoprene rubber. Thereafter, in the same manner as described above, sterilization treatment was performed at 124 ° C. for 30 minutes under a pressure of 0.2 MPa using a hydrothermal static sterilizer.
The following evaluation was performed about the infusion bag which performed this sterilization treatment.

(3-1. Evaluation of flexibility)
The infusion bag subjected to the sterilization treatment was suspended so that the port portion was on the lower side. An infusion jig was attached to the rubber stopper of the port portion, and the behavior was observed while the content liquid (distilled water) was actually dripped.
As a result, the infusion bag was flattened and the drip interval was almost the same as the liquid level of the content liquid in the infusion bag was lowered due to fullness. Further, the contents liquid did not flow back, and no signs of negative pressure in the infusion bag were observed.
From these results, it was confirmed that the bag body formed using the laminate had sufficient flexibility required for the infusion bag.

(3-2. Blocking resistance)
Five infusion bags subjected to sterilization treatment were stacked and allowed to stand at room temperature (25 ° C.) for 7 days, and then removed one by one, and the presence or absence of blocking was confirmed.
As a result, each bag could be removed smoothly, and the outermost surface of the lowermost infusion bag and the upper infusion bag on which the load was applied were not blocked.

<Comparative Example 1>
Using the same inflation film forming machine as in Example 1, only the same LLDPE used in Test Example 1 was put into the intermediate layer extruder to form a single layer film having a thickness of 225 μm. During film formation, the barrel temperature of the intermediate layer extruder was set to 190 ° C.
About the obtained single layer film, heat resistance was evaluated in the following procedures.

(Evaluation of heat resistance)
The single-layer film obtained above was cut into a size of 24 cm × 15 cm, two of them were overlapped so that the inner layer surfaces were in contact with each other, and three of the four sides were heat-sealed to prepare a three-sided bag.
This three-sided bag was filled with 500 mL of distilled water, and 50 mL of head space was provided and sealed. Then, the sterilization process for 30 minutes was performed at 118 degreeC lower 3 degreeC than the melting | fusing point of LLDPE under the pressure of 0.2 MPa using the hot water stationary type sterilizer. After cooling, the bag was taken out and the appearance was observed.
As a result, the inner surfaces of the bags were partially fused. In addition, a wrinkle occurred and deformation occurred. This is because the bacteria are sterilized under a pressure of 0.2 MPa for the purpose of preventing the bag from bursting, so that the inner surfaces of some of the bags are in contact with each other. This is thought to be due to fusion. In addition, in the hot water static type high-pressure steam sterilizer, since hot water circulates around the bag, the bag is kinked or deformed by the force of the flow, and since this is solidified by subsequent cooling, it is staggered. It seems that some deformation will remain.
As shown in these results, the bag formed using the LLDPE monolayer film does not have heat resistance that can withstand sterilization at 118 ° C., and naturally does not have heat resistance that can withstand sterilization at 124 ° C.

<Examples 2-3 and Comparative Examples 2-7>
Using the same HDPE, LDPE, LLDPE and crystal nucleating agent as used in Example 1, a layered product having a layer structure shown in Table 4 was prepared in the same procedure as in Example 1.
An infusion bag was prepared in the same procedure as in Example 1 using each obtained laminate.
The following evaluation was performed about the obtained laminated body or infusion bag. The results are shown in Table 4.

[Evaluation of heat resistance]
The laminate obtained above was cut into a size of 24 cm × 15 cm, two of them were overlapped so that the inner layer surfaces were in contact with each other, and three of the four sides were heat sealed to form a three-sided bag.
After filling this three-sided bag with 50 mL of distilled water and sealing it so that the inner surface partly adheres, using a hot water static type high-pressure steam sterilizer, at a pressure of 0.2 MPa, at 124 ° C. for 30 minutes. A sterilization treatment was performed.
The smoothness of the outer surface of the infusion bag after treatment and the degree of blocking of the inner surface were visually observed, and the heat resistance was evaluated according to the following criteria.
(Evaluation criteria)
A: The outer surface is smooth and the inner surface is not blocked.
B: Although some fine wrinkles are seen on the outer surface, blocking of the inner surface is not recognized.
C: The outer surface is smooth, but the inner surface is partially blocked.
D: The whole infusion bag is greatly deformed.

[Evaluation of transparency 1: Evaluation by light transmittance]
A polyethylene film having a light transmittance of 70% at a wavelength of 450 nm and a polyethylene film having a light transmittance of 55%, which were measured in the same manner as in Example 1-1 (1-1. Evaluation of transparency), were prepared. . These polyethylene films and the laminate were sterilized at 124 ° C. for 30 minutes under a pressure of 0.2 MPa using a hot water stationary high-pressure steam sterilizer. After the sterilization treatment, each polyethylene film and laminate were visually compared, and the transparency of the laminate was evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: It is more transparent than a polyethylene film having a light transmittance of 70%.
B: Transparency is inferior to a polyethylene film having a light transmittance of 70%, but it is more transparent than a polyethylene film having a light transmittance of 55%.
C: Transparency is inferior to a polyethylene film having a light transmittance of 55%.

[Transparency evaluation 2: Evaluation by clarity]
Using a TM-1D type transparency measuring device manufactured by Murakami Color Research Laboratory, light was incident perpendicularly to the laminate, and the percentage of light that passed through the laminate relative to the incident light was expressed as a percentage. When the percentage was 40% or more, A was evaluated, and when the percentage was less than 40%, B was evaluated.

  As described above, the laminate of the present invention is composed of a polyethylene resin excellent in flexibility, transparency, and impact resistance, and has heat resistance that can withstand sterilization at 124 ° C. Therefore, it is highly safe and can be used widely as a bag of various ring fluids.

  DESCRIPTION OF SYMBOLS 1 ... Intermediate | middle layer, 2 ... Outer layer, 3 ... Inner layer, 10 ... Laminated body, 20 ... Infusion bag, 21 ... Bag main body, 22 ... Port part

Claims (4)

A laminate having an outer layer, an inner layer, and an intermediate layer disposed therebetween,
The outer layer is composed of a polyethylene resin containing 20 to 100% by mass of a high-density polyethylene resin,
The inner layer is composed of a high density polyethylene resin;
The intermediate layer is a resin in which a crystal nucleating agent is added at a mass ratio of 1000 to 5000 ppm with respect to a mixed resin of 10 to 40% by mass of a high density polyethylene resin and 90 to 60% by mass of a linear low density polyethylene resin. A laminate for an infusion bag, characterized by comprising a composition.   The laminated body for infusion bags according to claim 1, wherein the crystal nucleating agent contains cyclohexanedicarboxylate.   The laminated body for a ring fluid bag according to claim 1 or 2, wherein the outer layer is composed of a mixed resin of 20 to 40% by mass of a high density polyethylene resin and 80 to 60% by mass of a low density polyethylene resin.   A bag-shaped bag body formed by heat-sealing the inner layers of the laminate for an infusion bag according to any one of claims 1 to 3, and the bag body attached to a peripheral portion of the bag body. An infusion bag comprising a port portion that enables communication between the inside and the outside.

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