JPS628757A - Liquid container - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to medical liquid containers such as infusion bags. In particular, the present invention relates to medical liquid containers that can withstand high-pressure steam sterilization and are collapsible, used in closed medical systems.

[Prior Art] Conventionally, medical bags such as infusion bags have generally been made of soft vinyl chloride resin. However, those made of soft vinyl chloride resin have poor processability, mechanical strength, Although it has excellent performance such as transparency and cold resistance,
There was a risk that additives, particularly plasticizers, contained in the resin composition would be eluted into the medical bag, impairing safety for living organisms.

Therefore, the use of various flexible synthetic resins is being considered as an alternative to such medical bags made of soft vinyl chloride resin. Polyolefin resins, which are also inexpensive, are the most promising.

However, it has been extremely difficult to produce desired medical bags using such polyolefin resins. In general, polyolefin resins have low dielectric loss and do not generate enough heat to cause welding even when a high frequency electric field is applied to them, so unlike vinyl chloride resins, high frequency sealing is impossible. Therefore, for example, two medical bags
When forming the polyolefin sheet from two polyolefin sheets, the sheets are overlapped and predetermined portions are welded by impulse sealing or heat sealing. However,
Unlike high-frequency seals, impulse seals and heat seals are difficult to weld into complex shapes, so it has been impossible to successfully form small-diameter openings provided at the upper end of medical bags.

On the other hand, polyolefin medical bags are manufactured by injection blow molding, in which a small-diameter opening is first precisely formed by injection molding, and then a parison having the opening is blown to form a thin container. Another manufacturing method is possible, but the lower end of the medical bag obtained in this way is thicker and harder than other parts, and the side ends are also difficult to blow mold to make them flat. Since the medical bag has a certain radius, when the liquid filled in the medical bag is discharged, the flexibility of the polyolefin prevents the inner surfaces from coming into close contact with each other while discharging the liquid. . Therefore, in medical bags manufactured by injection blow molding, the liquid inside the bags cannot be discharged quickly and completely.

[Problems to be Solved by the Invention] In recent years, closed systems have come to be used in medical treatments such as infusions in order to prevent liquid contents from coming into contact with the outside world. Medical liquid containers used in this closed system must be flexible enough to allow the liquid inside to be drained by gravity and the flexibility of the container material. In addition, this type of medical liquid container must have heat resistance that can withstand high-pressure steam sterilization in order to sterilize the liquid inside. Further, it is preferably made of a transparent material so that the liquid content can be monitored from the outside.

Conventionally, soft polyvinyl chloride and ethylene-vinyl acetate copolymer have been mainly used as materials for medical liquid containers. Soft polyvinyl chloride contains a large amount of plasticizer,
There is a risk that the plasticizer may be leached into the liquid content, which is considered a safety issue. Ethylene-vinyl acetate copolymer undergoes acetic acid removal during molding, and there is a risk that it will elute into the content liquid.
In addition, as it is, it does not have the heat resistance to withstand high-pressure steam sterilization, so the ethylene-vinyl acetate copolymer must be cross-linked by radiation irradiation to give it the specified heat resistance. It requires a process.

Therefore, the use of various flexible synthetic resins is being considered as a substitute for such soft polyvinyl chloride and ethylene-vinyl acetate copolymers. Polyolefin resins, which are inexpensive, are the most promising. However, since polyolefin resins are relatively hard, it has been extremely difficult to produce collapsible medical liquid containers. Furthermore, polyolefin resins generally have low dielectric loss and do not generate enough heat to cause welding even when a high frequency electric field is applied, so unlike vinyl chloride resins, high frequency sealing is impossible. Therefore, for example, when a medical liquid container is to be formed from two polyolefin sheets, the sheets are overlapped and predetermined portions are welded by impulse sealing or heat sealing. However, unlike high-frequency seals, impulse seals and heat seals are difficult to weld into complex shapes, so it has been impossible to successfully form a small-diameter opening provided at the upper end of a liquid container.

On the other hand, a polyolefin medical liquid container made by blow molding, which can integrally mold such a small-diameter opening and the container part, is also considered, but the medical liquid container obtained in this way has a lower end. The contents filled in the liquid container are thicker and harder than other parts, and no matter how flat the side edges are blow-formed, they still have a certain radius. The action of draining fluid is inhibited. Therefore, in a liquid container manufactured by blow molding, the flexibility of the polyolefin prevents the inner surfaces from coming into close contact with each other when discharging the content. Therefore, in liquid containers manufactured by blow molding, the liquid contained therein cannot be discharged quickly and completely.

[Means for solving the problem] A linear low density polyethylene 50 having an opening at the upper end.
Block copolymer 10-5 consisting of ~90% by weight, both end blocks composed of styrene units, and a hydrogenated intermediate block composed of conjugated diene copolymer units
A liquid container that can withstand high-pressure steam sterilization can be obtained by forming the polymer material in a mixture with 0% by weight.

[Operation] Next, the present invention will be explained in more detail based on the drawings. As shown in FIGS. 1, 2, and 3(a) and 3(b), the liquid container l of the present invention has a small-diameter opening 2 at the upper end, and the opening 2 and the shoulder According to the present invention, the liquid container 1 includes 50 to 90% by weight of linear low-density polyethylene (LLDPE), end blocks composed of styrene units, and a conjugated diene unit. It is formed from a mixture polymer material with 10 to 50% by weight of a block copolymer consisting of a hydrogenated intermediate block composed of copolymer units.

The range of the resin composition of the polymer material is 50% by weight or more and 90% by weight or less of LLDPE, and 1% by weight of the block copolymer.
It is necessary that the amount is 0% by weight or more and 50% by weight or less.

If the LLDPE is 90% by weight or more and the block copolymer is 10% by weight or less, the flexibility will be insufficient and the LL
DPE is 50% by weight or less, and block copolymer is 50% by weight or less.
If the amount is 0% by weight or more, moldability, particularly blow moldability, deteriorates. Particularly preferably LLDPE is 60% by weight or more and 90% by weight.
The content of the block copolymer is 20% by weight or more and 40% by weight or less.

In addition, the base of the block copolymer is a block copolymer consisting of both end blocks (10 to 40% by weight) composed of styrene and an intermediate block (90 to 60% by weight) composed of a conjugated diene copolymer. It is a polymer. The conjugated diene copolymer constituting the intermediate block is preferably polybutadiene and polyisoprene. By hydrogenating this intermediate block, the block copolymer used in the present invention can be obtained. This hydrogenation ratio needs to be 90% or more. Hydrogenated polybutadiene has an ethylene-butylene copolymer structure, and hydrogenated polyisoprene has an ethylene-butylene copolymer structure.
It has an ethylene-propylene copolymer structure, which improves heat resistance. Note that the end blocks made of styrene act as a high hardness component of the thermoplastic elastomer, and the middle block acts as a soft component, so if the end blocks are less than 10% by weight in the block copolymer, the strength will decrease. If the amount exceeds 40% by weight, the flexibility will be insufficient.

The above block copolymers used in the present invention are Kraton G-1650 and Kraton G-16 from Shell Chemical Co., Ltd.
52, Kraton Q-1657, etc., and can be easily obtained.

On the other hand, linear low density polyethylene (LLDPE) has 0
．． It has a density of 915 to 0.940 g/cm" and a melting point of 120°C or higher. LLDPE differs from general low-density polyethylene in that its molecular structure is (cH
2) It has a structure in which a short chain branch of an α-olefin is bonded to a straight chain of n. α-olefins include butene-1, which has 4 carbon atoms, 4-methylpentene-1, which has 6 carbon atoms, and octene-1, which has 8 carbon atoms.

LLDPE, like general low-density polyethylene,
It has good flexibility and high transparency, while, like long-chain high-density polyethylene, it has high heat resistance and good mechanical strength.

Next, the method for manufacturing the liquid container l of the present invention will be described in the fourth section below.
5 and 6, the upper end has a small diameter opening 42, the shoulder 43, and the container 4.
A blow-molded product 41 of the above-mentioned polymer material is molded. It is preferable that the shoulder portion 43 of the blow molded product 41 has a radius as small as possible, and that the container portion 44 has a mold space that is as flat as possible. In order to improve the workability of heat welding in the vicinity of the side and lower peripheral edges of the portion 44, and to improve the flexibility of the container portion 4 of the obtained liquid container 4 when draining the contents, the shoulder portion This is because it is not possible to press 43 and thermally weld its sides.

As mentioned above, the blow-molded product 41 is
As shown in FIG. 7, the container portion 44 is pressed by the press device 101. In FIG. 7, the container part 44 is pressed with a flat surface, but as shown in FIG.
1 may pressurize the container portion 44.

Next, while maintaining the pressed state, press the side peripheral edge 5.
As shown in FIGS. 7 and 8, the areas near the 0 and lower peripheral edges 51 are externally heated and thermally welded using sealers 102 and 202. At this time, portions near the side peripheral edge 50 and the lower peripheral edge 51 are thermally welded and simultaneously fused and cut. Alternatively, the side peripheral edge 5 that is no longer needed outside the heat welded part
0 and the lower peripheral edge 51 are cut by a cutter 103 as shown in FIG. 9 to obtain a desired liquid container 1. The sealers 102 and 202 to be used may be appropriately selected, such as a heat sealing method, an impulse sealing method, or the like. In addition, care must be taken if the inner surfaces of the parts to be thermally welded are not brought into sufficient contact with each other, as there is a risk of the parts peeling off due to rebound resilience during welding, resulting in defective welding.

Although the lower peripheral edge portion 51 is not shown in FIGS. 7 to 9, it is in substantially the same state as the side peripheral edge portion 50.

In this way, the liquid container 1 is obtained, and the side peripheral edge 5 and the lower peripheral edge of the liquid container 1 are the heat-welded portions near the side peripheral edge 50 and the lower peripheral edge 51 of the blow-molded product 41, respectively. This corresponds to

In addition, a liquid container whose container portion 44 is pressed into a curved shape by the press device 201 has a larger internal volume than one whose container portion 44 is pressed into a flat shape, and the content liquid can be discharged more smoothly.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1.2 A polymeric material having the following composition was obtained, and a blow molded article having openings was obtained by blow molding. Press the container part of this blow-molded product so that the side and lower peripheral parts are in contact with each other, and heat this part with a hot plate hot sealer at a temperature of 190°C and a pressure of 2 kg/crn for about 6 seconds to weld it, and then it is no longer necessary. The resulting end was cut to obtain a liquid container with a width of 120 mm and a length of 250 mm.The wall thickness of the container portion of this liquid container was 0.
There was no uneven thickness at 3 mm.

1. LLDPE (Product name: Ultzex Mitsui Petrochemical Industries ■) Il,
Block copolymer (trade name: Kraton G-1850, Siel Kagaku ■) 520 mJL of water was poured into this container, and a high-density polyethylene film (1.01 mm thick) was heat-sealed to the opening.
After sealing the container, a rubber stopper was attached. The liquid container thus obtained was autoclaved at 1156C for 40 minutes. In addition, according to the usual infusion technique, attach the infusion set to the girdle stand, penetrate the bottle needle of the infusion set from the rubber stopper at the opening into the inside of the liquid container, and measure the height from the rubber stopper to the infusion needle by 70°.
cm, the drain was opened, and the amount of dripping from the infusion needle was fixed at about 50 mfL/min, and the relationship between the amount of drained fluid and time and the amount of remaining fluid were measured. These results are shown below.

[Effects of the Invention] The liquid container of the present invention described above has the following advantages.

(1) The material is highly safe as it does not contain any highly leachable components such as plasticizers.

(2) It has heat resistance that can withstand high-pressure steam sterilization.

(3) Since it is sufficiently flexible, it can be suitably used in closed systems.

(4) Excellent strength and water vapor permeability.

(4) Since it is highly transparent, the liquid content can be monitored from the outside.

[Brief explanation of the drawing]

Fig. 1 is a front view showing one embodiment of the medical bag of the present invention, Fig. 2 is a plan view of the same embodiment, and Fig. 3a is the same embodiment (
1) II'Ia-IIIa cross-sectional view, FIG. 3b is a longitudinal cross-sectional view of the same embodiment, FIG. 4 is a front view showing an embodiment of the blow-molded product for producing the medical bag of the present invention, and FIG. Fig. 5 is a top view of the blow-molded product, Fig. 6 is a side view of the blow-molded product, and Figs. 7 to 9 are drawings showing each step of the method for manufacturing a medical bag of the present invention. be.

Claims (1)

[Claims] 1. A liquid container having an opening at the upper end and in which the opening and the container are substantially integrally molded, comprising 50 to 90% by weight of linear low-density polyethylene and styrene units. It is characterized by being formed of a polymer material consisting of a mixture with 10 to 50% by weight of a block copolymer consisting of both end blocks composed of and a hydrogenated intermediate block composed of conjugated diene copolymer units. A liquid container that can withstand high-pressure steam sterilization. 2. The liquid container according to claim 1, wherein the conjugated diene copolymer unit constituting the intermediate block is a copolymer unit of ethylene and butylene. 3. The liquid container according to claim 1, wherein the conjugated diene copolymer unit constituting the intermediate block is a copolymer unit of ethylene and isoprene. 4. The liquid container according to any one of claims 1 to 3, wherein the opening portion and the container portion are substantially integrally molded by blow molding. 5. The side part and the lower peripheral part of the container part are heat-enclosed so that the peripheral part of the container part can easily collapse due to the pressure difference between the inside and outside of the container part. Liquid container according to item 4. 6. The liquid container according to any one of claims 1 to 5, wherein the container portion has a wall thickness in a range of 0.05 mm to 0.5 mm. 7. The liquid container according to claim 5, wherein the thermal welding is performed by heat sealing or impulse sealing.