JPH0230940B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flat and crushable container such as a medical container such as a blood bag having a uniform wall thickness, and a method for manufacturing the same.

In the general blow molding method, the wall thickness error is 30% in the circumferential direction and 30% in the vertical direction for round bottles.
% uneven thickness occurs. Furthermore, it is known that when forming a container with a flat shape like the container of the present invention, the error in wall thickness can reach three times the above value. For this reason, in the conventional technology, parison control,
Efforts have been made to reduce wall thickness errors using techniques such as pre-blowing, but no satisfactory solution has yet been found. Taking a blood bag as an example, it is important to use the bag so that the blood inside does not remain in the bag, but if the bag has uneven flesh, the blood cannot be completely drained, so as mentioned above, It is very important to make the wall thickness of the bag thin and uniform.

In general, when a liquid inlet/outlet, a tube connector, etc. are integrally molded into the parison at one end of the container as in the present invention during blow molding, the wall thickness of the container portion adjacent to the insert parts such as the tube connector, etc. However, the wall thickness is thicker than other parts of the container. Taking blood bags as an example, this causes a problem in terms of product functionality in that a large amount of blood remains when blood is discharged, as described above. If this type of container is to be obtained by blow molding, it usually takes more than 40 seconds for the cycle to make one container. This would require too much time to mass produce containers, resulting in high costs.

In order to eliminate uneven thickness of the container, the above-mentioned insert part is inserted between two sheets and the container is formed by a seal molding method. However, this sheet forming method tends to trap foreign matter such as dust and bacteria between the sheets, and special attention must be paid to conditions such as sheet storage and manufacturing environment. Since this type of medical container is particularly required to have a clean interior, the above-mentioned situation should be avoided as much as possible.

Therefore, the main object of the present invention is to configure the liquid inlet/outlet with a predetermined structure and to make the wall thickness of the container thin and uniform so that the contents can be discharged without leaving any residue and a clean blood bag can be obtained. The present invention aims to provide a flat collapsible container such as a medical container such as a medical container.

Another object of the present invention is to provide a method for producing flat, collapsible containers in a clean state by using a blow molding method, which makes the wall thickness of the container thin and uniform, the container production speed is faster than that of the conventional method. It is in.

That is, the present invention has a hollow insert part having a liquid outflow means, a mounting part that grips and seals a part of the insert part on one side, and an annular seal including the seal part on one side. The inner surface on the side of the bag from the insert part is a smoothly continuous composite curved surface communicating with the insert part, (thickness of the bag part other than the seal part) ±15 error
To provide a flat and collapsible container characterized by:

The present invention further provides that the mounting part is fitted with an insert part such as a fluid inlet/outlet port, a tube connector, etc., and the inner surface of the bag part side from the insert part is flat and crushable, forming a continuous compound curved surface communicating with the insert part. It provides a container.

Further, the present invention provides a method of inserting an insert part having fluid inflow/outflow means into the lower end opening of the parison immediately after the parison is extruded from the die, and clamping the insert part with a parison holding tool so that the parison covers the outer periphery of the insert part. The lower end opening is closed to form a mounting part, and while high-pressure air is blown into the parison to inflate the parison, the parison clamping tool is synchronized with the resin discharge amount of the die and forcibly pulled down a certain distance at a constant speed to remove the parison. The parison, which has been stretched and inflated sufficiently to protrude from the parison half mold, is held between the half molds adjacent to the mounting portion while adjusting its internal pressure, and the peripheral edge is sealed to form a flat bag portion. Then, open the cooling half-split mold and release it, and reduce the thickness error of the bag part other than the seal part by ±15%.
The present invention provides a method for manufacturing a container that is flat and collapsible.

Furthermore, the present invention provides the above-mentioned container manufacturing method characterized by blowing a chemical solution together with air during cooling of the parison.

Furthermore, the present invention provides the above-mentioned container manufacturing method characterized in that purified air is used for blowing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the flat collapsible container and method for manufacturing the same according to the present invention will be described in detail with reference to preferred embodiments shown in the accompanying drawings.

In the schematic illustration of FIG. 1, a is before use, b
1 indicates a state in which blood or the like is charged, c indicates a state in which blood or the like is discharged, 1 indicates a bag portion, 2 indicates an insert component, and 25 indicates a mounting portion. In this type of container, it is desirable that the wall thickness of the seal constituting the bag portion 1 is uniform over the entire bag portion, and if the wall thickness is uniform as in the container of the present invention, as shown in Fig. 1c. When the content liquid such as blood is squeezed out by squeezing the bag part 1 due to the blood being discharged by its own weight, it can be almost completely drained except for the insert part 2. However, as described above, conventional products tend to be extremely thick, especially from the joint with the insert part and the seal (pinch) part to the bag part, and also have a poor shape. This caused the problems mentioned at the beginning of the specification. Accordingly, the present invention aims to provide a bag (container) with a thin and uniform wall thickness, and the manufacturing method thereof will be explained in detail below with reference to the diagrams shown in FIGS. 2 to 4.

In Figures 2 to 4, the front view is shown as a for ease of understanding.
The side view is shown by b. First, as shown in FIG. 2, a resin having flexibility and heat resistance is extruded from an extruder 3 into a parison 4. At the very beginning of the extrusion of the parison 4, the insert part 5 supported by the insert part support tool is inserted into the opening at the lower end of the parison, and the parison 4 covers the outer peripheral edge of the insert part 5 by the parison holding tool 6, and the lower end of the parison is pushed out. The opening is closed and the mounting portion 25 is formed by clamping. In this case, the insert component support and the parison clamp can be used in common as will be described later.

Next, as shown in Fig. 3, high-pressure air is blown into the parison from the opening of the insert part or the pipe 7 provided in the parison clamping tool to expand the parison while synchronizing it with the resin discharge rate of the extruder 3. While the parison is in a molten state, the parison clamping tool 6 is forcibly pulled down a certain distance at a certain speed to stretch the parison so that the thickness of the parison becomes uniform. The drawing speed for drawing the parison downward in this way is preferably 1 to 4 times the linear speed at which the parison is discharged from the die head. Select appropriately depending on the shape and wall thickness. Also,
The air to be blown at this stage is preferably high pressure air of 1 to 7 kg/cm ² . By blowing in high-pressure air, the parison is blown up to about three times the size of extrusion, and it is important to expand the parison so that it becomes larger than the seal line during subsequent molding with the parison mold. The focus of the method of the present invention is to achieve a state in which exactly two sheets are press-formed, and as a result, a container with a thin and uniform wall thickness can be obtained. In addition, since the parison is stretched while it is in a molten state, no distortion remains, and post-treatment such as heat treatment is not required, and it does not shrink even after heat treatment, resulting in a high product yield. The quality is also constant, and the scale is reliable when used as an infusion bag, although it is not necessary when used as a blood bag. However, blood bags do not require a scale.

After the parison is sufficiently expanded while being stretched in this way, as shown in FIG. to seal. At this time, it is important to make sure that the parison, which has been expanded into a certain shape by pre-blowing, is press-molded using a mold, so that the internal pressure of the parison is not lowered too much and wrinkles occur, and that it is not raised too high and further expanded. It is to adjust the pressure to For this reason,
For example, the parison clamping tool 6 is provided with a pressure regulating valve (not shown) for maintaining the internal pressure of the parison constant even when the volume of the parison decreases from the time of expansion to the time of molding. In reality, a pressure regulating valve is selected based on the internal pressure that allows the parison of the desired shape to maintain its shape. As a result, the expanded, uniformly thin parison is flattened and molded into the bag 1 in the mold as it is, and no abnormally thin or thick parts, wrinkles, etc. are produced.

Another important point in the process of molding the expanded parison with a mold is the cross-sectional shape of the mold. Since the expanded parison has a spherical shape, it is necessary to configure the mold so that the entire concave surface of the mold is in close contact with the spherical surface. For example, as shown in FIG. 5(a), if the cross section of the mold is made up of a circular arc portion 10 and a straight portion 11, parison will begin to adhere as shown by the dotted line in the figure, and the parison will begin to adhere to the corner portion 12. Because it does not adhere, the wall thickness in this area may become thinner or tear. Therefore, corner part 1
2 to make the radius of curvature of the arc portion 10 larger, or if the cross section of the mold is made up of an arc as shown in FIG. 5b, the entire surface of the spherical expanded parison will adhere uniformly to the spherical surface of the mold No abnormally thin parts will be produced during molding.

The parison pre-blown under the above conditions is flattened with a mold 8 and blow-molded by final blowing. At this time, high-pressure air is also blown into the parison in the mold 8 from the tube (nozzle) 7, and the parison is pressed against the inner surface of the mold to form the mold. At the same time as this molding, the molded bag with the insert is cooled by blowing air. It is also possible to blow in a medicinal solution such as an anti-coagulant together with the air during cooling. It is preferable to clean the air used during the pre-blow, final blow, and cooling blow as described above. Since the system for manufacturing bags from such stretched and expanded parisons is a completely closed system, it is completely hygienic as long as clean air is used, and is particularly suitable for manufacturing medical bags. Further, as shown in FIG. 6, the mounting portion 25 is preferably an integrally molded product to which an insert part 5 such as a fluid inlet/outlet port for liquid, a tube connector, etc. is mounted.

Here, in the container of the present invention, the inner surface on the bag side from the insert component is constituted by a smoothly continuous compound curved surface communicating with the insert component, as shown in FIG. By having such a configuration, in addition to the above-mentioned absence of uneven thickness, it becomes possible to discharge contents such as blood without remaining due to dead weight discharge. The insert parts are preferably cleaned before use before assembling the bag.

After cooling, the mold 8 is opened to release the insert part-parison molded assembly. The parison is then cut directly below the extrusion die, preparing it for the next container production cycle. By completing such a manufacturing process, the manufacturing time for conventional containers of the same type can be significantly shortened, and containers of constant quality can be manufactured in large quantities at low cost. The wall thickness of the bag part of this container other than the sealed part depends on the properties of the resin.
A thickness of 0.2 to 1.0 mm, preferably 0.3 to 0.6 mm, is advantageous in terms of molding and use.

Next, the apparatus for manufacturing containers of the present invention and its control function will be briefly explained.

As diagrammatically shown in FIG. 7, for extruding the resin, an extruder 14 and an accumulator 15, preferably a ring plunger type, capable of achieving a high parison extrusion speed are used, and are operated by a hydraulic cylinder 16. The extrusion speed is set in advance to a desired speed using a hydraulic cylinder control valve.

The parison extruded from the die 17 is taken up (lowered) by operating a stage (table) to which an insert component support (parison clamp 18) is attached using a variable speed cylinder 19. This variable speed cylinder 19 synchronizes the resin extrusion speed with a signal from a program 20 suitable for the parison clamping process and the taking process and a signal detected by a potentio transducer 21 to detect the operation of the hydraulic cylinder 16 through a servo amplifier 22. A signal is input to the servo valve 23, and the cylinder 19 is actuated by the hydraulic unit 24 to perform synchronous take-up of the parison. As described above, the parison clamp holder 18 can be provided with the air and/or chemical liquid injection nozzle 7, pressure regulating valve, etc.

When the parison clamp holder 18 finishes pulling down the parison 4 to the expanded and stretched state, the hydraulic cylinder 25 is actuated to press the mold 8 against the parison to perform blow molding. Furthermore, a linear head motor may be used as the power for taking the parison instead of the hydraulic system shown. Examples manufactured by the above-mentioned manufacturing process using such a manufacturing apparatus will be described below.

Example Using a ring plunger accumulator type extruder, a parison with a diameter (outer diameter) of 34 mm and a wall thickness of 1 mm is extruded using a ring plunger accumulator type extruder onto polypropylene insert parts arranged in an array using a parison clamping tool. Then, the insert component was attached by fusing the parison using an insert component supporter, and the bottom of the parison was closed to form a mounting portion 25. Subsequently, 5 kg/cm ² of air was blown into the parison, and at the same time, it was pulled down a predetermined length (180 mm) at the same speed as the parison extrusion speed (linear speed 4.2 m/min).
During this time, the amount of air is automatically changed as the parison is extruded to create a parison with a wall thickness of 0.4 mm and a diameter of 82 mm.
It was inflated into a cylindrical body with a length of 180 mm and closed at both ends.
Next, the pressure inside the parison was maintained at the pressure at the time of expansion, the parison was held between half molds, and 7 kg/cm ² of air was blown into the parison for blow molding. The manufacturing time required until the next manufacturing preparation was completed was about 20 seconds.
The wall thickness of the bag part of the obtained container other than the seal part is 0.4
mm, and the error in wall thickness was ±15%.

Example Using EVA resin, a parison was extruded and clamped in the same manner as in the example, and the parison was extruded at a speed of 4.2 m/min while blowing 5 kg/cm ² of air.
It was pulled 180mm downward at twice the speed. Thereafter, blow molding was performed in the same manner as in the example. The container manufacturing time was approximately 15 seconds. The wall thickness of the bag portion of the obtained container other than the seal portion was 0.4 mm, and the error in wall thickness was ±15%.

As is clear from the above description, the flat and collapsible container of the present invention and the method for manufacturing the same provide many advantages, including the following.

(1) By clamping the parison at the very beginning of extrusion and forcibly pulling it down in synchronization with the resin discharge amount while inflating, the blow molded product can be made thinner and with much higher precision than conventional methods. The thickness can be made uniform, which results in a bag from which the liquid contents, such as blood, can be almost completely drained.

(2) In conventional blow molding, the mold was clamped by waiting for the parison to fall down to the required length due to the discharge speed and its own weight, but in the present invention, the process cycle time is reduced because the parison is forcibly pulled down. can be shortened.

(3) Since the parison is stretched in a molten state, crystal orientation does not occur, and the product therefore has good dimensional stability due to heat. In particular, blood bags are filled with anticoagulant and infusion bags are similarly filled with infusion agents, so they are sterilized by heat such as steam pressure sterilization in an autoclave, but the container of the present invention is stretched. Despite this, no heat shrinkage occurs.

(4) Since the parison is sealed in a molten state, there is no need to provide a separate sealing means such as adhesive or high-frequency welding.

(5) In addition, in the flat and collapsible container of the present invention, the bag has a uniform wall thickness, and the inner surface on the side of the bag from the insert part is composed of a smoothly continuous compound curved surface that communicates with the insert part. Therefore, it is possible to realize a container that can be discharged by weight without leaving any contents behind.

[Brief explanation of drawings]

FIG. 1 shows the state of the container of the present invention, where a is a sectional view before use, b is a sectional view when liquid is charged, and c is a sectional view when liquid is discharged.
Figures 2 to 4 show each process of blow molding, Figure 2 is the parison extrusion process, Figure 3 is the pre-blowing process,
Figure 4 is a diagram of the final blow process,
Figure 5 is a side sectional view of an example of the structure of the parison mold.
FIG. 6 is a front view of the insert part, and FIG. 7 is a diagram of the apparatus for manufacturing the container of the present invention. Explanation of symbols 1... Bag, 2, 5... Insert part, 3... Extruder, 4... Parison, 6... Parison clamping tool, 7... High pressure air blowing nozzle, 8... Parison mold, 10... Arc part, 11... Straight line part, 12... Corner part, 13... Composite curved surface, 14... Extruder, 15
...Accumulator, 16, 19, 25...Hydraulic cylinder, 17...Die, 18...Parison clamping tool, 2
0... Program, 21... Potentiometer transducer, 22... Servo amplifier, 23... Servo valve, 24... Hydraulic unit, 25... Mounting part.

Claims (1)

[Scope of Claims] 1. An annular seal including a hollow insert part having a liquid outflow means and a mounting part for gripping and sealing a part of the insert part on one side, and including the seal part on one side. The inner surface of the bag part from the insert part is a smoothly continuous composite curved surface that communicates with the insert part, and the wall thickness of the bag part other than the seal part is A flat, collapsible container characterized by an error of ±15% or less. 2. The attachment part is equipped with an insert part such as a fluid inlet/outlet port, a tube connector, etc., and the inner surface of the bag part side from the insert part forms a smoothly continuous compound curved surface that communicates with the insert part. A flat, crushable container as described. 3. The flat and collapsible container according to claim 1 or 2, wherein the wall thickness of the bag portion other than the seal portion is 0.2 to 1.0 mm. 4. The flat and collapsible container according to claim 1 or 2, wherein the wall thickness of the bag portion other than the seal portion is 0.3 to 0.6 mm. 5. Immediately after the parison is extruded from the die, insert the insert part having a fluid inflow/outflow means into the lower end opening of the parison, and use the parison clamping tool to clamp the insert part so that the parison covers the outer periphery of the insert part, thereby closing the lower end opening of the parison. The parison is expanded by blowing high-pressure air into the parison, and the parison clamp is forcibly pulled down a certain distance at a constant speed in synchronization with the resin discharge amount of the die to stretch the parison. A parison that has been sufficiently inflated to protrude from the split mold is held between the half molds adjacent to the mounting portion while adjusting its internal pressure, and the peripheral portion is sealed to form a flat bag portion;
A method for producing a flat and collapsible container, characterized in that the cooling half-split mold is opened and released, and the wall thickness error of the bag portion other than the seal portion is within ±15%. 6. The manufacturing method according to claim 5, characterized in that a chemical solution is blown in together with air during cooling of the parison. 7. The manufacturing method according to claim 5 or 6, characterized in that the blown air is purified.