JPH0421495B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to medical bags such as infusion bags, and more specifically, the present invention relates to a medical bag such as an infusion bag, and more specifically, a synthetic resin that can easily and almost completely drain the liquid that can be crushed when the liquid is drained; In particular, it relates to polyolefin liquid containers. [Conventional technology] Conventionally, medical bags such as infusion bags
Generally, those made of soft vinyl chloride resin were used. However, while products made of soft vinyl chloride resin have excellent performance such as processability, mechanical strength, transparency, and cold resistance, additives contained in the resin composition, especially plasticizers, are There was a risk that it would elute into the inside of the bag, compromising safety for living organisms. Therefore, the use of various flexible synthetic resins is being considered as an alternative to such flexible vinyl chloride resin medical bags. Polyolefin resins are the most promising because they are inexpensive. 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, when a medical bag 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 the small-diameter openings provided at the upper ends of medical bags. On the other hand, medical bags made of polyolefin have been manufactured using an injection blow molding method 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 could be considered, but the lower end of the medical bag obtained in this way is thicker and harder than the other parts, and the side ends are also difficult to blow mold to make them flat. Since the bag has a certain degree of 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, medical bags made by injection blow molding are unable to quickly and completely drain the liquid inside. [Problems to be Solved by the Invention] Conventionally, medical bags such as infusion bags have generally been made of soft vinyl chloride resin. However, while products made of soft vinyl chloride resin have excellent performance in terms of processability, mechanical strength, transparency, and cold resistance, the additives contained in the resin composition, especially the plasticizer, are liquid. There was a risk that it would elute into the inside of the container, compromising 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, since polyolefin resins are relatively hard, it has been extremely difficult to produce collapsible medical bags. 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. For example, when a medical bag 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 was impossible to successfully form the small-diameter openings provided at the tops of medical bags. . On the other hand, it is also possible to manufacture medical bags made of polyolefin by blow molding, which can integrally mold such a small-diameter opening and the body, but the medical bag obtained in this way has a lower end. Because the wall is thicker and harder than other parts, and no matter how flat the side edges are blow-molded, they still have a certain radius, so the liquid filled in the liquid container is drained. When doing so, the flexibility of polyolefin prevents the inner surfaces from coming into close contact with each other and discharging the liquid inside. Therefore, medical bags made by blow molding are unable to drain the liquid quickly and completely. [Means for Solving the Problems] Although the present invention aims to provide a synthetic resin medical bag suitable as an infusion bag, etc., the inventor has developed various shapes of the synthetic resin medical bag. As a result of our study, we found that an opening with a predetermined shape,
The sides and lower periphery of the body of a medical bag that has been blow-molded so as to integrally form the shoulders and body are welded to the inside of the body by impulse sealing or heat sealing. The above object was achieved by making the area near the periphery of the body easily collapse due to the pressure difference on the outside, and by preventing the length of the short axis of the shoulder from exceeding 30 mm. [Operation] Next, the present invention will be explained in more detail based on the drawings. As shown in FIGS. 1, 2, and 3a and 3b, the medical bag 1 of the present invention has a small-diameter opening 2 at the upper end.
It is a synthetic resin blow-molded product in which the body 4 is integrally molded, but the side periphery 5 and lower periphery 6 of the body 4 are heat welded, and there is substantially no radius in these parts. There is no. Therefore, the inner surfaces of the body 4 of the medical bag 1 can be in contact with each other as a whole due to their flexibility when the bag 1 is not filled with liquid and when the liquid is discharged. Furthermore, in the medical bag 1, it is necessary that the short axis length B of the shoulder portion 3 connected to the small-diameter opening 2 does not exceed 30 mm. That is, shoulder part 3
Since the side edges 7 are practically impossible to heat weld, the shape remains as blow-molded, so even when the liquid inside is drained, its inner surfaces are perfectly aligned due to its flexibility. Therefore, if the length B of the minor axis of the shoulder portion 3 exceeds 30 mm, the ratio of the amount of residual liquid to the total amount of liquid inside becomes large, which is disadvantageous from an economic point of view. This is clear from the table below. This table shows that the length A of the long axis of the medical bag is 100 mm, 120 mm, and 150 mm.
The remaining amount of liquid in the sample was measured when the length B of the short axis was changed from 15 mm to 45 mm. As is clear from this table, regardless of the length of the long axis, when the length of the short axis exceeds 30 mm, the remaining amount of liquid in the container increases rapidly.

[Table] Unit ml
In addition, by providing a protrusion 9 extending from the upper part to the lower part approximately in the center of the body part 4, air corresponding to the volume of the space formed by the liquid content and the protrusion 9 can be filled into the medical bag 1. The remaining amount of the fluid can be easily checked visually, and when the fluid transfusion is completed, all the air present in the medical bag enters the partial space of the convex part 9, making it especially difficult for suction and medical bags. Unless pressurized from the outside, it will not come out of the medical bag, so when performing normal infusions, there is no risk of it flowing out of the medical bag and flowing into the body. Although there are various synthetic resins constituting the medical bag 1 of the present invention, polyolefin resins are preferred. Polyolefins include low-density polyethylene, polypropylene, etc. with a bending modulus of 4000 kg/ ^cm2 or less, preferably a density of 0.915~
0.930g/ ^cm3 low density polyethylene, density 0.90~
0.91 g/cm ³ of polypropylene. Furthermore, unlike general low-density polyethylene, its molecular structure is composed of (CH ₂ )n linear chains containing α-olefin or other monomers, preferably α-olefin, particularly preferably α-olefin having 4 to 8 carbon atoms. Linear Low Density Polyethylene (Linear Low Density Polyethylene)
LLDPE) may also be used. This LLDPE has good flexibility and high transparency, etc. like general low-density polyethylene with linear branching, but it also has high heat resistance and good mechanical properties like long-chain high-density polyethylene. Medical bags that can be steam sterilized can be manufactured by using LLDPE that is strong and can be blow molded. like this
LLDPE preferably has a density of 0.910 to 0.935 g/cm ³ , particularly preferably 0.915 to 0.930 g/cm ³ . In addition, these polyolefin resins include
Antioxidants such as Irganox 1010 and other stabilizers may be included as necessary. The wall thickness of the medical bag 1 of the present invention is as follows:
The opening 2 is 1 to 4 mm, preferably 1.5 to 3 mm, and the body 4 is 0.05 to 0.5 mm, preferably 0.1 to 0.3 mm. If the wall thickness of the body is less than 0.05mm, it will be easily damaged and lack safety as a medical bag. Also,
If the wall thickness is 0.5 mm or less, the body 4 will not be easily crushed, and the amount of residual liquid will increase. Note that the wall thickness of the body portion 4 is substantially unchanged between the vicinity of the central portion and the vicinity of the side and lower peripheral portions. Further, the opening of the medical bag 1 is closed by thermally welding a polyolefin film or the like until the medical bag 1 is used, thereby sealing the inside of the medical bag 1. Note that various methods can be considered for sealing the opening end, and there are also other methods for sealing the opening 2.
Known methods such as forming a thread in advance and sealing it with a cap that is screwed onto the thread can be applied. The medical bag 1 of the present invention having such a configuration is manufactured as follows. As shown in FIG. 4, FIG. 5, and FIG.
A blow-molded product 41 of synthetic resin in which 4 is integrally molded is molded. Shoulder portion 43 of blow molded product 41
It is preferable that the shape is such that the short axis length is 30 mm or less at maximum, and that the body 44 has a mold space that is as flat as possible. This is done in order to press the entire body of the blow-molded product 41, which will be described later, and to improve the workability of heat welding near the side and lower peripheral edges of the body 44. This is to improve the flexibility of the body 4 when discharging the liquid inside it, and to prevent the sides of the shoulder 43 from being thermally welded by pressing the shoulder 43. Blow molded product 4 blow molded as above
1, the body portion 44 is pressed by a press device 101 as shown in FIG. In FIG. 7, the body 44 is pressed with a flat surface, but the body 44 may be pressed with a curved pressing device 201 as shown in FIG.
Next, while maintaining this pressed state, the vicinity of the side peripheral edge 50 and lower peripheral edge 51 are externally heated and thermally welded using sealers 102 and 202, as shown in FIGS. 7 and 8. 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 unnecessary lateral peripheral edge 50 and lower peripheral edge 51 outside the heat-welded part are cut off with a cutter 103 as shown in FIG. 9 to obtain the desired medical bag 1. In addition,
The sealers 102 and 202 used are appropriately selected depending on the polyolefin material used, such as those based on a heat sealing method, those using an impulse sealing method, etc. In addition, care must be taken because if the inner surfaces of the parts to be thermally welded are not brought into sufficient contact with each other, 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, medical bag 1 is obtained, but
The lateral periphery 5 and the lower periphery 6 of the medical bag 1 are the same as the lateral periphery 5 of the blow-molded product 41, respectively.
0 and the heat welded portion near the lower peripheral portion 51. Furthermore, a medical bag whose body part 44 is pressed into a curved shape by the press device 201 has a larger internal volume than one whose body part 44 is pressed into a flat shape, and the liquid inside can be discharged more smoothly. can. [Example] The present invention will be described in more detail with reference to Examples below. Example LLDPE (trade name: Novatek-U, manufactured by Mitsubishi Chemical Industries, Ltd.) was melted and plasticized at 200°C to obtain a blow-molded product having a predetermined opening, a shoulder, and a thin body. Press the body of this blow-molded product to bring it into contact near the side and lower peripheral edges, heat this area with a hot plate hot sealer at a temperature of 180℃ and a pressure of 2Kg/ ^cm2 for about 6 seconds, and then weld it. The broken end was cut off to obtain a 1500ml medical bag. In addition, the wall thickness of the container part of this medical bag is 0.3
There was no uneven thickness at mm. Also, the length of the short axis of the shoulder is
The length of the major axis was 150 mm. 1100ml of water and air in the resulting medical bag
After injecting 50 ml, a tube with a drip needle at the tip was connected to the open end, and the medical bag was turned upside down to drain the water, and the total amount of water drained reached 1040 ml. In addition, the temperature of this medical bag is 115℃,
Although the bag was autoclaved for 40 minutes at a pressure of 1500 g/cm ² , no substantial deformation was observed in the medical bag. Additionally, this medical bag was subjected to leachate tests and acute toxicity tests based on the Japanese Pharmacopoeia's 10th revised general test method "Plastic container test method for infusions", and as a result, it passed both tests. It was hot. Comparative Example 1 Blow molding was performed in the same manner as in Example 1,
LLDPE (Product name: Novatec-U Mitsubishi Chemical Industries, Ltd.
A 1500 ml blow-molded product was obtained. In this comparative example, where the side and lower peripheral edges are not heat welded, the wall thickness of the body of this blow-molded product is 0.3 mm.
However, the bottom wall was considerably thicker than other parts. Also, the length of the short axis of the shoulder is
The length of the major axis was 150 mm. After injecting 1100ml of water and 50ml of air into this blow-molded product, a tube with an intravenous needle at the tip was connected to the open end, and when the blow-molded product was turned upside down to drain the water, the water was discharged. The total amount of water reached 700 ml, but it did not reach 1040 ml as in the example. Comparative Example 2 Blow molding was carried out in the same manner as in Example 1, and after pressing the body and welding the vicinity of the side and lower peripheral edges, the unnecessary ends were cut off and LLDPE (product name: Novatek-U) was applied. 1500 manufactured by Mitsubishi Chemical Industries, Ltd.
I got a ml medical bag. The wall thickness of this medical bag was 0.3 mm, and there was no uneven thickness. In addition, the length of the short axis of the shoulder is 45 mm, and the length of the long axis is 150 mm.
It was warm in mm. After injecting 1100ml of water and 50ml of air into this medical bag, a tube with an intravenous needle at the tip was connected to the open end, and when the medical bag was turned upside down to drain the water, the water was drained. The total amount reached 900ml, but in the case of the example 1040ml
It didn't reach ml. [Effects of the Invention] As described above, the present invention provides a blow-molded synthetic resin liquid container having an opening at the upper end, in which the opening, the shoulder, and the body are integrally formed. , The side and lower peripheries of the torso are heat welded so that the vicinity of the periphery of the torso can easily collapse due to the pressure difference between the inside and outside of the torso, and the length of the short axis of the shoulder is 30 mm.
Since the medical bag is characterized in that it does not exceed 100%, it is possible to obtain a liquid container suitable for use as an infusion bag, etc., which is made of polyolefin with high biosafety and allows easy and almost complete drainage of the contents.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the medical bag of the present invention, FIG. 2 is a plan view of the same embodiment, and FIG.
The figure is an a-a cross-sectional view of the same embodiment, Figure 3b is a longitudinal cross-section of the same embodiment, and Figure 4 is a front view showing an embodiment of the blow-molded product for producing the medical bag of the present invention. Figure 5 is a plan view of the same blow-molded product,
FIG. 6 is a side view of the blow molded product, and
7 to 9 are drawings showing each step of the method for manufacturing a medical bag according to the present invention. 1...Medical bag, 2...Opening, 3...Shoulder, 4...Torso, 5...Side periphery, 6...Lower periphery, 7...Side end, 8..., 9...Protrusion, 41
... Blow molded product, 42 ... Opening, 43 ... Shoulder, 44 ... Body, 101 ... Press device, 20
1...Press device, 102...Sealer, 202
... Sealer, 49 ... Convex portion, 50 ... Lateral peripheral portion, 51 ... Lower peripheral portion, 103 ... Cutter.

Claims (1)

[Claims] 1. The upper end opening, the shoulder, and the body are integrally blow-molded, the side and lower peripheral edges of the body are heat-welded, and the short axis length of the shoulder is substantially A synthetic resin liquid container used as a medical bag, characterized in that the outer diameter matches the outer diameter of the upper end opening and does not exceed 30 mm. 2. The liquid container according to claim 1, wherein the body has a wall thickness in a range of 0.05 to 0.5 mm. 3. The liquid container according to claim 1, wherein the synthetic resin is polyolefin. 4. The liquid container according to claim 1, wherein the synthetic resin is linear low-density polyethylene having a flexural modulus of 4000 Kg/cm ² or less. 5. The liquid container according to claim 1, wherein the synthetic resin is low-density polyethylene or polypropylene having a flexural modulus of 4000 Kg/cm ² or less. 6 Claim 1 in which the thermal welding is performed by a heat sheet or an impulse seal
The liquid container according to any one of Items 1 to 5.