JPS61287728A - Liquid vessel and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture a medical bag, easy and perfect of discharging the liquid content by a method wherein the part of the vessel of a blow molded product is pushed to weld the inner surfaces of side peripheral rim and lower part peripheral rim with each other through fusion welding under a condition that they are contacted mutually, thereafter, unnecessary part at the outside thereof is removed by cutting. CONSTITUTION:A parison made of polyethylene and having an opening section 12 is formed into the part of vessel 13 through blow molding in a blow mold 104. Subsequently, said vessel part 13 is pinched by a press device 105 and the side peripheral rim and lower peripheral rim of said vessel are welded by a sealer 106 through fusion welding under a condition that both of the inner surfaces of them are contacted with each other, further, the side and lower rim sections 14 of the blow molded product, which are located at the outside of the welded section and showing round figure, are removed by cutting with a cutter 107. Polyolefin-based resin is employed, therefore, there is no possibility of eluation of plasticating agent while the peripheral rim section is welded through thermal fusion welding, therefore, the discharging of liquid content is easy and perfect, whereby the vessel may be suitable for the medical bag such as transfusion bag or the like.

Description

Detailed Description of the Invention Object of the Invention (Technical Field) The present invention relates to a liquid container that can be used in medical bags such as infusion bags and a method for manufacturing the same. The present invention relates to a liquid container made of synthetic resin, particularly polyolefin, from which the liquid inside can be easily and completely drained, and a method for manufacturing the same.

(Prior Art) 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 such as processability, mechanical strength, 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) Therefore, to date, no polyolefin medical bag suitable for use as an infusion bag has been developed.The present invention aims to solve the problems of conventional products. It is.

That is, an object of the present invention is to provide a novel medical bag and a method for manufacturing the same.The present invention also aims to provide a synthetic resin medical bag suitable as an infusion bag, etc., and a method for manufacturing the same. A further object of the present invention is to provide a synthetic resin medical bag in which the contents can be easily and completely drained, and a method for manufacturing the same.

Structure of the Invention (Means for Solving Problems) In order to achieve the above-mentioned thin object, the present inventor conducted various studies on the shape and manufacturing method of a synthetic resin medical bag, and as a result, developed an opening with a predetermined shape. The side and lower periphery of the medical bag, which has been injection blow molded or direct blow molded, is welded inwardly by impulse sealing or heat sealing to form a rounded part of the lateral periphery and a lower periphery. The present invention was achieved by discovering that a suitable medical bag can be obtained by removing the thick portion.

That is, the present invention is a synthetic resin medical bag having an opening at the upper end and made by injection blow molding or direct blow molding, characterized in that the side and lower peripheral edges are heat welded. It is a medical bag.

The present invention further provides a method for forming a sealed parison having an opening in a predetermined shape by injection molding a synthetic resin, blow molding the parison to form a thin container portion, and then This is a method for manufacturing a medical bag, characterized in that the lower peripheral portion is cut.

(Specific explanation of configuration) Next, the present invention will be explained in more detail based on the drawings.

As shown in FIG. 1 and FIGS. 2a and 2b, the medical bag 1 of the present invention is an injection blow-molded product of synthetic resin having a small-diameter opening 2 at the upper end. Part 3
The side periphery 4 and the lower periphery 5 of the container part 3 are heat-welded, and there is substantially no radius in these parts, and the wall thickness is substantially the same as that of other parts of the container part 3 and is thin. be. Therefore, in the medical bag 1, the inner surfaces of the container portions 3 can be in contact with each other as a whole due to their flexibility in a state in which the liquid content is not filled and in a state in which the liquid content is discharged.

Further, in the medical bag 1, it is desirable that the shoulder portion 6 of the container portion 3 connected to the small-diameter opening 2 has a small radius in the axial direction. That is, the shoulder portion 6
, since its side edge 7 is virtually impossible to heat weld,
It has the same shape as injection blow molding and has a radius in the direction orthogonal to the axis. ), it is possible for the inner surfaces to be in complete contact with each other even when the content liquid is drained due to its flexibility, and for this reason, the shoulder portion 6 has a large radius in the axial direction This is because there is a risk that a large amount of the liquid content may remain in the shoulder portion 6 when the liquid content is discharged.

Although there are various synthetic resins constituting the medical bag 1 of the present invention, polyolefin resins are preferred.

Examples of the polyolefin include low density polyethylene and polypropylene, preferably having a density of 0.915 to 0.9.
30g/Crrf17) Low density polyethylene, density 0
, 90-0, 91 g/cm".Furthermore, unlike general low-density polyethylene, its molecular structure is a straight chain of (CH2)n containing d-olefin or other monomer, preferably terolefin. , particularly preferably a linear low-density polyethylene (Li
near Lov Density Polyethy
The use of LLDPE) is also conceivable. This L
LDPE has good flexibility and high transparency like general low-density polyethylene with linear branching, but it also has high heat resistance and good mechanical strength like long-chain high-density polyethylene. LLDPE is known as a flexible synthetic resin that can be blow molded, and by using this LLDPE, medical bags that can be steam sterilized can be manufactured. Such LLDPE has a density of 0.910 to 0.9
35g/crn” is preferable, especially 0.915~
0.930 g/cm" is preferable.

Furthermore, these polyolefin resins may contain antioxidants and other stabilizers as necessary.

In the medical bag 1 of the present invention, the wall thickness of the opening 2
1 to 4 mm, preferably 1.5 to 3 mm, and the container part 3
0.05~0.5mm, preferably 011~0.3m
It is m. If the wall thickness of the container portion is 0.05 mm or less, it will be easily damaged and lack safety as a medical bag. Moreover, if the wall thickness is 0.5 mm or more, the container part will be difficult to collapse, and the function as a medical bag will not be satisfactory. In the container portion 3, the wall thickness is substantially the same between the vicinity of the center and the vicinity of the side and lower peripheral edges.

Further, the open end of the medical bag 1 is closed by, for example, heat-welding a polyolefin film or the like until the medical bag 1 is used, thereby sealing the inside of the medical bag 1. Various methods can be considered for sealing the opening end, and other known methods include, for example, forming a thread in the opening 2 in advance during injection molding 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.

That is, first, the synthetic resin described above is heated and melted at an appropriate temperature, and as shown in FIG. 3, a neck mold 101 and a core mold f are formed.
I 102 and cavity mold 103 are closed and molten polyolefin is injected around core mold 102 to form sealed parison 10 . At this time, the portion formed in the space surrounding the neck mold lO1 and the core mold 102 of the sealed parison 10 is formed into the final shape which is the shape of the opening 2 of the medical bag l to be obtained. Next, the fourth
As shown in the figure, a sealed parison 10 is supported by a neck mold 101 and a core mold 102, and a cavity mold 103 is formed.
The sealed parison 10 is then pulled out and transferred to a blow mold 104 as shown in FIG. Blow mold 10
Close 4.

As shown in FIG. 6, the core mold 102 is extracted and air is blown into the sealed parison 10. The blow mold 104 used at this time preferably has a mold space in which the container portion 13 of the injection blow molded product 11 to be obtained is as flat as possible.
In order to improve the workability of heat welding near the side and lower peripheral edges of the container part 13, and further to improve the flexibility of the container part 3 of the obtained medical bag 1 when the liquid inside is drained. desired. The blow mold 104 also has a small diameter opening 12 (medical bag 1
This is the opening 2. ) Shoulder portion 16 of container portion 13 connected to
However, it is preferable that the mold space has a shape with a small radius in the axial direction. A portion of the medical bag 1 remains as a shoulder, so if the radius is too large in the axial direction, a large amount of the liquid will remain in this shoulder when the liquid is drained. be.

In this way, the sealed parison lO is blow molded to form the container part 1.
After cooling, the neck mold 10 is formed as shown in FIG.
1 and the blow mold 104 are opened, and the injection blow molded product 11 is
Take out.

In addition, in the method for manufacturing a medical bag of the present invention, the above steps are similar to the general injection blow molding method of synthetic resin, and the mold etc. used can be arbitrarily changed based on known technology. It is something.

Injection blow molded product 1 that was injection blow molded as described above
1 therefore has its lateral periphery 14 and lower periphery 1
5 has a radius, and the lower peripheral edge 15 is connected to the container part 1.
It is thick compared to other parts of No. 3.

Next, the injection blow molded product 11 is pressed against the container portion 13 by a press device 105, as shown in FIG. Note that with this press device 105, it is not necessary to press the entire surface of the container portion 13, but only the portions near the side peripheral portion 14 and the lower peripheral portion 15 to be thermally welded, that is, the rounded end portion of the injection blow molded product 11. At the outermost part where the thick parts can be removed (of course, it is also possible to heat weld the inner parts, but it is not economically preferable), press the parts where the inner surfaces can contact each other. It is sufficient.

The injection blow molded product 11 is thus pressed into the press device 105.
While maintaining the pressed state, the areas near the side peripheral edge 14 and lower peripheral edge 15 are externally heated and thermally welded using a sealer 106 as shown in FIG. At this time, a portion near the side peripheral edge portion 14 is thermally welded and simultaneously cut by fusing. Alternatively, the unnecessary side peripheral edge 1 outside the heat welded part
4 is cut with a cutter 107 as shown in FIG. 10 to obtain a desired medical bag l. The sealer 106 to be used may be appropriately selected depending on the material of the polyolefin used, 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 part 15 is not shown in FIGS. 8 to 10, it is in substantially the same state as the side peripheral edge part 14.

In this way, a medical bag 1 is obtained, and the lateral periphery 4 and the lower periphery 5 of the medical bag 1 are located near the lateral periphery 14 and the lower periphery 15 of the injection blow-molded product 11, respectively. This corresponds to the heat welded part.

Moreover, the medical bag 1 of the present invention can also be obtained by direct blow molding based on a known technique.

(Example) Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 LLDPE (trade name: Ultzex, manufactured by Mitsui Petrochemical Industries, Ltd.) was melted and plasticized at 200°C, injection molded into a sealed parison, and then blown into a predetermined shape with high pressure air of 5 kg/c rn'. An injection blow-molded product was obtained having an opening of 100 mm and a thin container section. The container part of this injection blow molded product was pressed to bring the sides and lower peripheral edges into contact, and these parts were heat-sealed for 0.1 minute using a hot plate hot sealer at a temperature of 18o@c and a pressure of 2Kg/cm''. The unnecessary end was cut off to obtain a medical bag with a capacity of 800 m1.The wall thickness of the container part of this medical bag was 0.3 m.
There was no uneven thickness at m.

550 ml of water and 50 ml of air in the resulting medical bag
After injecting 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 discharged reached 520 ml.

Furthermore, this medical bag was sterilized in an autoclave for 40 minutes at a temperature of 115°C and a pressure of 500 g/cm'', but no substantial deformation was observed in this medical bag. Japanese Pharmacopoeia 10th Revised General Test Method “Plastic Container Test Method for Infusion”
As a result of conducting eluate tests and acute toxicity tests based on the above, the product passed both tests.

Comparative Example 1 Injection blow molding was performed in the same manner as in Example 1, and LLD
PE (Product name: Urtozex, Mitsui Petrochemical Industries ■
An injection blow molded product with a volume of 800 ml was obtained. The wall thickness of the container part of this injection blow molded product was 0.3 mm, but the bottom part thickness was considerably thicker than other parts. Add 500 ml of water and 5
After injecting 0 m1 of air, a tube with a drip needle at the tip was connected to the open end, and the injection blow molded product was turned upside down to drain water, and the total amount of water discharged reached 400 m1. did.

Effects of the Invention As described above, the present invention provides a synthetic resin medical bag having an opening at the upper end and a blow-molded opening and a container part, which is caused by the pressure difference between the inside and outside of the container part. Polyolefin with high biological safety because it is a liquid container that can withstand high-pressure steam sterilization, characterized in that the side and lower peripheral edges of the container part are heat-welded so that the parts near the local edges of the container part can be easily crushed. It is possible to obtain a medical bag suitable for use as an infusion bag or the like, which is made of high-quality materials and whose contents can be easily and completely drained.

Furthermore, the present invention involves injection molding a synthetic resin into a sealed parison having an opening of a predetermined shape, blow molding the parison to form a thin container portion, and then forming a container portion of this injection blow molded product. Pressure is applied to bring the inner surfaces of the injection blow molded product into contact with each other at least in the vicinity of the lateral and lower peripheral edges, and then the lateral and lower peripheral edges are thermally welded by an external heating method. This method of manufacturing a liquid container that can be used in medical bags is characterized by cutting off unnecessary outer side and lower peripheral parts, so it is easy to produce medical bags with the above-mentioned excellent performance. It can be provided safely and hygienically.

[Brief explanation of drawings]

FIG. 1 is a front view showing one embodiment of the medical bag of the present invention, FIG. 2a is a cross-sectional view of the same embodiment along Ila-11a, and FIG. 2b is a longitudinal cross-sectional view of the same embodiment along Il b-II b. FIG. 3 to FIG. 10 are drawings showing each step of the method for manufacturing a medical bag of the present invention. 1... Medical bag, 2, 12... Opening 3.13
... Container part, 4... Medical bag side peripheral part, 5.
...Lower periphery of medical bag. 10... sealed parison, 11... injection blow molded product. 14... Side peripheral edge of the injection blow molded product, 15... Lower peripheral edge of the injection blow molded product. Patent applicant Ken Yamakoshi - Figure 9 f f05 1, - Backpack for Yasushi Fusa. tr-one injection molded product 14- λ dimension and flow molded product 111 $1611 θ5-Ares reward 106--Sealer 707-cutter

Claims (11)

[Claims] (1) In a synthetic resin medical bag having an opening at the upper end and a blow-molded opening and a container,
A liquid container that can withstand high-pressure steam sterilization, characterized in that the side and lower peripheral edges of the container part are heat-welded so that the vicinity of the periphery of the container part can be easily crushed due to the pressure difference between the inside and outside of the container part. (2) The liquid container according to claim 1, wherein the container portion has a wall thickness in a range of 0.05 mm 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. (5) The liquid container according to claim 1, wherein the synthetic resin is high-density polyethylene or polypropylene. (6) Claims 1 to 5 in which the thermal welding is performed by heat sealing or impulse sealing.
A liquid container described in any of paragraphs. (7) After forming a synthetic resin into a sealed parison having an opening of a predetermined shape and blow-molding the parison to form a thin container part, press the container part of the blow-molded product to seal the blow-molded product. The inner surfaces are brought into contact with each other at least in the vicinity of the lateral and lower peripheral edges, and then the lateral and lower peripheral edges are thermally welded by an external heating method, and the unnecessary lateral parts outward from the thermally welded areas are and a method for manufacturing a liquid container, comprising cutting the lower peripheral edge. (8) The method for manufacturing a medical bag according to claim 7, wherein the synthetic resin is polyolefin. (9) The method for manufacturing a liquid container according to claim 7, wherein the synthetic resin is linear low-density polyethylene. (10) The method for manufacturing a liquid container according to claim 7, wherein the synthetic resin is low density polyethylene or polypropylene. (11) The method for manufacturing a liquid container according to any one of claims 7 to 10, wherein the external heating method is a heat sealing method or an impulse sealing method.