JP7646344B2 - Storage bag manufacturing method and storage bag manufacturing device - Google Patents

Description

The present invention relates to a method and an apparatus for manufacturing a storage bag that stores a stored material, and more specifically, to a method and an apparatus for manufacturing a storage bag that has a port portion that discharges a stored material such as a medical liquid to the outside.

Storage bags for storing stored materials such as medical fluids are known. For example, the storage bag includes a bag body for storing the stored material and a port portion welded to the bag body, the bag body being formed, for example, from a resin sheet, and the port portion being welded to the bag body using a heating mold (see, for example, Patent Documents 1 and 2).

JP 2007-245490 A Japanese Utility Model Application Publication No. 1-144037

Patent Document 1 describes a welding method that uses a mold to perform two-stage heat pressing. Specifically, in the welding method described in Patent Document 1, the resin sheet near the port portion of the bag body is first welded by the first stage of heat pressing, and during this heat pressing, the resin sheet near the port portion and the periphery of the port portion is preheated. After that, the port portion is efficiently welded to the bag body by quickly performing the second stage of heat pressing.

The port section to be welded to the bag body can have a variety of shapes. For example, as described in Patent Document 2, a port section in which the portion of the port section that is welded to the bag body is boat-shaped is known. For example, when a boat-shaped port section is welded to the bag body by a two-stage heat press, the following problems can occur. That is, a portion of the resin forming the port section may be excessively melted, and in this case, the molten resin may be subjected to pressure from the mold and seep out (push out) so as to protrude to the outside from the welded portion between the port section and the bag body. Hereinafter, the portion of the resin that has seeped out from the welded portion and solidified after cooling may be referred to as molten burr.

The above-mentioned molten burrs reduce the strength, safety, and other performance properties of the storage bag, so it is necessary to prevent the occurrence of such molten burrs in storage bags.

In view of the above problems, one aspect of the present invention aims to provide a method for manufacturing a storage bag and a manufacturing device for the storage bag that prevent the occurrence of molten burrs.

In order to solve the above problems, a method for manufacturing a storage bag according to one aspect of the present invention is a method for manufacturing a storage bag having a bag body having a storage section for storing a storage material and a port section for discharging the storage material in the storage section to the outside, and includes a bag forming process for forming the bag body having a band-shaped welding area and an opening where the resin sheets are welded to each other by sealing a part of the peripheral portion of the overlapped resin sheets, an insertion process for inserting the port section into the opening defined by the welding area, a first heating process for welding the resin sheet of the opening at a position separated from the port section inserted inside the opening using a heating mold, a first cooling process for cooling at least an edge of the port section that is closer to the resin sheet welded in the first heating process, and a second heating process for heating a welded portion that is a part of the port section inserted inside the opening and the resin sheet around the welded portion using a heating mold to weld the welded portion to the resin sheet.

In one aspect of the present invention, a manufacturing device for a storage bag includes a bag body having a storage section for storing a storage material, and a port section that is welded to the bag body and discharges the storage material in the storage section to the outside. The bag body has a band-shaped welding area in which overlapping resin sheets are welded to each other and an opening. The bag body includes a first heating section having a first heating die that seals the opening by welding the resin sheet at a position separated from the port section inserted inside the opening, a cooling section that has a cooling die corresponding to the outer shape of the welded part, which is a part of the port section inserted inside the opening, and that cools at least the edge of the port section that is closer to the resin sheet welded by the first heating section, and a second heating section having a second heating die that heats the welded part and the resin sheet around the welded part to weld the welded part to the resin sheet.

According to one aspect of the present invention, the portion of the port that is prone to molten burrs is cooled, and then the portion to be welded in the port is welded to the resin sheet. This makes it possible to provide a method for manufacturing a storage bag and a manufacturing device for the storage bag that prevent the generation of molten burrs.

1 is a plan view showing the appearance of a storage bag manufactured by a storage bag manufacturing method according to an embodiment of the present invention; 2 is a cross-sectional view taken along line AA in FIG. 1. 1 is a schematic diagram showing a configuration of a storage bag manufacturing apparatus according to an embodiment of the present invention. FIG. 4 is a schematic diagram for explaining a main part of the manufacturing apparatus shown in FIG. 3 . 1 is a flowchart showing an outline of an example of a method for manufacturing a storage bag in one embodiment of the present invention. 4 is an enlarged view showing the periphery of a welded portion of a storage bag manufactured by a method for manufacturing a storage bag according to an embodiment of the present invention. FIG. 13 is a graph showing temperature changes over time for a number of test samples that were processed from the first heating step to the second cooling step while changing the cooling time in the first cooling step from 0 seconds to 5 seconds.

One embodiment of the present invention will be described below with reference to the drawings. Note that the following description is provided to facilitate a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. In addition, the shapes and dimensions (length, width, etc.) of the configurations shown in each drawing in this application do not necessarily reflect the actual shapes and dimensions, and have been modified as appropriate to clarify and simplify the drawings.

In this embodiment, a storage bag having three ports for storing a stored object such as a medical liquid is used as an example to explain a method for manufacturing the storage bag. Note that the storage bag manufactured by the method for manufacturing the storage bag in one aspect of the present invention is not limited to this. The method for manufacturing the storage bag in one aspect of the present invention is applicable to various types of storage bags, and can be applied, for example, to a storage bag having one port (e.g., an infusion bag) or a storage bag having two or more ports.

In the following description, first, the storage bag and the manufacturing device for the storage bag will be described with reference to Figures 1 to 5. Then, the manufacturing method for the storage bag in one embodiment of the present invention (hereinafter, sometimes simply referred to as this manufacturing method) will be described.

(Storage bag)
Fig. 1 is a plan view showing the appearance of a storage bag 1 manufactured by the manufacturing method of a storage bag in this embodiment. As shown in Fig. 1, the storage bag 1 includes a bag body 12 having a storage section 2 and three port sections 3. This storage bag 1 may be a single-use product (a so-called single-use bag) that is used in a manner that is discarded after one use (single use), or may be a product that can be used multiple times.

Here, to facilitate understanding of the method for manufacturing a storage bag in one embodiment of the present invention, the features of the present invention will be briefly described below.

The storage bag 1 in this embodiment is used, for example, as a medical bag. Such a storage bag 1 is required to have the desired performance as a product. Specifically, the storage bag 1 is required to have the performance to appropriately prevent contamination of the stored matter (typically liquid) stored in the storage section 2 due to the inclusion of a foreign matter other than the stored matter in the storage section 2. In addition, as a medical bag, the bag body 12 is required to be formed of a transparent or semi-transparent material so that the stored matter can be visually confirmed. In addition, the storage bag 1 is also required to have the following performance. That is, the bag body 12 in the storage bag 1 is made of a flexible resin sheet, and the port section 3 has an internal space for discharging the stored matter to the outside of the storage section 2 and is made of a hard material such as resin. In the storage bag 1, the port section 3 is firmly bonded to the resin sheet so that the stored matter does not leak, and the inside of the storage section 2 is at least liquid-tightly sealed.

As described above, the port portion 3 can be firmly attached to the resin sheet by, for example, performing a two-stage heat press using a mold. However, depending on the shape of the port portion 3, a part of the part of the port portion 3 that is welded to the resin sheet (hereinafter sometimes referred to as the welded part) may have a structure that makes it difficult for heat to escape. As a result, a part of the welded part melts more easily than other parts. Also, the resin sheet adjacent to a part of the welded part melts more easily than the resin sheet adjacent to the other parts of the welded part. As a result, a part of the welded part or the molten resin sheet may seep into the storage portion 2 and harden, forming a molten burr.

In a storage bag in which the molten burrs have occurred, there is a risk that the molten burrs will break the resin sheet due to factors such as the application of external forces when the storage bag is in use. In addition, if the internal pressure of the bag body increases when the storage bag is in use, the molten burrs will fall off and become mixed into the stored material.

The inventors conducted extensive research and discovered that, in the two-stage heat pressing method, by adding a step of appropriately cooling the port portion 3, it is possible to firmly bond the port portion 3 to the bag body 12 while appropriately preventing the occurrence of molten burrs. Furthermore, the method for manufacturing a storage bag in this embodiment can achieve the above-mentioned effects while suppressing an increase in the takt time (the execution time of the manufacturing process) for manufacturing the storage bag 1.

(Bag body)
The bag body 12 in the storage bag 1 of this embodiment is, for example, rectangular and is formed from a flexible resin sheet. The bag body 12 has a welding region 20, four seal parts 21, and a hole part 22. In each of three sets consisting of a combination of two adjacent seal parts 21 in the four seal parts 21, one port part 3 is inserted between the two adjacent seal parts 21, and the port part 3 is welded to the resin sheet. In the storage bag 1 of this embodiment, the four seal parts 21 and the three port parts 3 are located around one short side of the rectangular bag body 12, and the hole part 22 is located around the other short side. The welding region 20 is a band-shaped region formed by welding two overlapping resin sheets together, and is located so as to surround the outer periphery of the storage part 2 except for the part where the seal part 21 and the port part 3 are located. The hole portion 22 is a rectangular through-hole that can be used, for example, to hang and hold the storage bag 1 using a holder such as a hook.

The reservoir 2 in the bag body 12 stores liquids such as medical fluids, infusions, cell culture fluids, culture media, and nutrient solutions. The reservoir 2 is formed by stacking rectangular resin sheets of the same size in a plan view and then welding the outer edges of the stacked resin sheets.

The resin sheet constituting the bag body 12 may be, for example, a multilayer film in which multiple sheets of the same type of resin film are laminated, or a multilayer film in which multiple types of resin films are laminated. The above-mentioned resin sheet is, for example, a multilayer film in which three layers of resin film are laminated. The above-mentioned resin sheet may also be a single-layer film.

The resin film constituting the resin sheet may be made of, for example, polyethylene-based resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE), or ethylene vinyl alcohol (EVOH). From the viewpoint of ensuring the gas barrier properties of the bag body 12, it is preferable that the resin sheet includes an EVOH film. In addition, polyester-based resins such as polypropylene, polyethylene terephthalate, and polybutylene terephthalate, nylon-based resins, etc. may also be used as the material for the resin film.

Methods for welding the resin sheets include, for example, heat welding, high-frequency welding, ultrasonic welding, etc. As described below, the welding area 20 is formed by welding two overlapping resin sheets together in the area other than the opening 40, with the area where the seal portion 21 and the port portion 3 are located being defined as an opening 40.

(Sealing part)
Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1. As shown in Fig. 2, the seal portion 21 is formed by welding two resin sheets 21a and 21b. A welded portion 31, which is a part of the port portion 3, is located between the two seal portions 21. The welded portion 31 and the resin sheet 21a are welded to each other, and the welded portion 31 and the resin sheet 21b are welded to each other.

(Port section)
1 and 2, the port portion 3 is a member having a cylindrical internal space 31b for discharging the stored matter in the storage portion 2 to the outside, and has a welded portion 31 and a cylindrical portion 32. The storage bag 1 in this embodiment has three port portions 3 on one side of the bag body 12 having a rectangular shape. The number and locations of the port portions 3 may be changed as appropriate.

The welded portion 31 in the port portion 3 is inserted into the opening 40 of the bag body 12 and then welded to the resin sheet. The welded portion 31 is, for example, approximately rhombus (so-called boat-shaped) in the cross-sectional view shown in FIG. 2. The length of the welded portion 31 in the longitudinal direction (long axis direction) and transverse direction (short axis direction) in the cross-sectional view shown in FIG. 2 is greater than the diameter of the cylindrical portion 32.

The welded portion 31 has an end 31a that is closer to the seal portion 21 in the cross-sectional view shown in FIG. 2. This end 31a is the part where melt burrs are likely to occur when the welded portion 31 and the two resin sheets 21a and 21b are welded together.

The shape of the welded portion 31 is not particularly limited and can be changed as appropriate, and may be, for example, a cylindrical or rectangular tube shape. In addition, the shape of the welded portion 31 may have a thin plate-like blade at the end 31a closer to the seal portion 21 in the cross-sectional view shown in Figure 2, so that it melts due to the welding heat and improves adhesion with the resin sheet. Even in welded portions 31 of these shapes, the end 31a is a part where melt burrs are likely to occur.

The cylindrical portion 32 of the port portion 3 has an internal space that communicates with the internal space 31b of the welded portion 31. Using the port portion 3, the stored matter can be discharged from the storage portion 2 to the outside, and can also be injected into the storage portion 2. The cylindrical portion 32 may have a protrusion that protrudes from the outer periphery of the cylindrical portion 32 to prevent a tube or the like from coming off when connected to the cylindrical portion 32. Although not shown, the cylindrical portion 32 may have a cap attached to open and close the cylindrical portion 32, and a screw thread may be formed on the outer periphery of the cylindrical portion 32 to attach the cap.

Examples of the material of the port portion 3 include polyethylene-based resins such as LDPE, LLDPE, and HDPE, and polypropylene-based resins. The material of the port portion 3 is preferably a material that has a melting point close to the melting point of the resin sheet that forms the bag body 12. Specifically, the difference in melting point between the port portion 3 and the resin sheet is preferably within 20°C, and more preferably within 10°C. This is to facilitate welding of the port portion 3 and the resin sheet.

(Retention bag manufacturing equipment)
Next, a manufacturing apparatus 100 as an example of an apparatus for carrying out the present manufacturing method will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a schematic diagram showing the configuration of the manufacturing apparatus 100. Fig. 4 is a schematic diagram for explaining a main part P1 of the manufacturing apparatus 100 shown in Fig. 3. Fig. 4 shows a schematic plan view of the main part P1 of the manufacturing apparatus 100 as viewed in the vertical direction.

As shown in Figures 3 and 4, the manufacturing apparatus 100 includes a support and transport section 110, a first heating section 101, a second heating section 102, a cooling section 103, and a control section 150. In the manufacturing apparatus 100 as an example, a port section 3 is inserted into a bag body 12 having an opening 40 manufactured in a previous process, and various processes are performed to manufacture a storage bag 1. The opening 40 is a portion defined by a welding area 20. The manufacturing apparatus 100 is configured to manufacture the storage bag 1 bag by bag (batch manufacturing). It is to be noted that this manufacturing method can of course also be applied to an apparatus that continuously manufactures storage bags 1.

(Support and transport section)
In FIG. 3, an example of the support state of a bag body 12 having an opening 40 in the support and transport section 110 before processing by the manufacturing apparatus 100 is shown diagrammatically within an area D1 surrounded by a dashed line.

In the support and transport unit 110, for example, the bag body 12 having the opening 40 is supported by being suspended by the support unit 130. The support unit 130 is attached to the welded area 20 of the bag body 12 to support the bag body 12, and is movably attached to the transport path 115 formed by, for example, a rail. The support unit 130 may support the bag body 12 by sandwiching the welded area 20 from both sides of the bag body 12. The support unit 130 is disposed near each of the two long sides of the bag body 12. The support unit 130 may also be configured to include a mechanism for supporting the bag body 12 by suction. The support and transport unit 110 has a drive mechanism (not shown) such as a motor, and moves the support unit 130 along the transport path 115 using the drive mechanism.

Three port parts 3 are inserted into predetermined positions in the opening 40. For example, the support and transport unit 110 may have three port parts 3 inserted into the opening 40, and in this case, the three port parts 3 inserted into the opening 40 may be temporarily fixed to the resin sheets 21a and 21b so that this state can be maintained. Alternatively, the first heating unit 101 may be configured to insert three port parts 3 into the opening 40, and in this case, the first heating unit 101 inserts the three port parts 3 into the opening 40 and heats the resin sheet of the opening 40.

The three ports 3 are inserted into the opening 40 at their respective predetermined positions, and the hanging bag body 12 is moved to the positions of the first heating section 101, the second heating section 102, and the cooling section 103, respectively, to perform various processes, thereby producing the storage bag 1.

(First heating section)
The first heating unit 101 forms the seal portion 21 by using a heating mold to heat the resin sheet of the opening 40 at a position separated from the welded portion 31 of the port portion 3 inserted between the overlapped resin sheets. The first heating unit 101 has first heating dies (first heating dies) 101a and 101b. The first heating die 101a has three recesses 101c formed therein so as to correspond to the shapes of the three port portions 3. The first heating die 101b facing the first heating die 101a has the same shape as the first heating die 101a. The first heating dies 101a and 101b each have a built-in heater (not shown) made of, for example, an electric heating wire. This allows heating by the first heating unit 101.

The first heated molds 101a and 101b may be structured so that the contact portion between the welded portion 31 and the resin sheets 21a and 21b is preheated while forming the seal portion 21. For example, the first heated molds 101a and 101b may have a recess 101c shape that has a gap between the first heated molds 101a and 101b and the resin sheets 21a and 21b when the first heated molds 101a and 101b are in contact with each other via the resin sheets 21a and 21b.

(Second heating section)
The second heating unit 102 heats the welded portion 31 and the resin sheets 21a and 21b around the welded portion 31, thereby welding the welded portion 31 to the resin sheets 21a and 21b. The second heating unit 102 has second heating dies (second heating dies) 102a and 102b. The second heating die 102a has three recesses 102c formed therein so as to correspond to the shapes of the three port portions 3. The second heating die 102b facing the second heating die 102a has the same shape as the second heating die 102a. The second heating dies 102a and 102b each have a built-in heater (not shown) made of, for example, an electric heating wire. This allows heating by the second heating unit 102.

The second heated molds 102a and 102b have recesses 102c shaped to bring the second heated molds 102a and 102b into close contact with the resin sheets 21a and 21b when the second heated molds 102a and 102b are in contact with each other via the resin sheets 21a and 21b so as to weld the welded portion 31 to the resin sheets 21a and 21b. In other words, the second heated molds 102a and 102b have recesses 102c that are smaller in shape than the recesses 101c in the first heated molds 101a and 101b.

The first heated molds 101a and 101b of the first heating section 101 and the second heated molds 102a and 102b of the second heating section 102 may be molds of known structure (shape), and detailed explanations of the structure of these molds will be omitted.

(Cooling section)
The cooling part 103 cools at least the end (edge) 31a of the port part 3 that is closer to the seal part 21. The cooling part 103 has cooling dies (cooling metal molds) 103a and 103b that have a shape corresponding to the outer shape of the welded part 31. The cooling die 103a has three recesses 103c formed therein so as to correspond to the shapes of the three port parts 3. The cooling die 103b that faces the cooling die 103a has the same shape as the cooling die 103a.

The cooling section 103 is designed to maintain the temperature of each of the cooling dies 103a and 103b at a relatively low temperature, for example, about 15°C. For example, a flow path through which a cooling medium such as cooling water passes is formed inside the cooling dies 103a and 103b. In addition, the cooling dies 103a and 103b have a shape in which the gap between each of the cooling dies 103a and 103b and the welded part 31 is reduced compared to the first heated dies 101a and 101b when the cooling dies 103a and 103b are in contact with each other via the resin sheets 21a and 21b. In other words, the cooling dies 103a and 103b have recesses 103c shaped such that the gap between each of the cooling dies 103a and 103b and the welded part 31 is reduced compared to the gap between each of the first heated dies 101a and 101b and the welded part 31.

The cooling dies 103a and 103b may have, for example, rubber or glass mesh attached to the opposing surfaces. This allows the cooling dies 103a and 103b to apply pressure uniformly to the entire welded portion 31 and the resin sheets 21a and 21b. This allows the cooling speed of the end 31a in the port portion 3 to be increased.

(Control Unit)
The control unit 150 comprehensively controls the operation of each unit of the manufacturing apparatus 100. The control of each unit by the control unit 150 will be described in detail later together with the description of the present manufacturing method.

(Method of manufacturing the storage bag)
Next, a method for manufacturing the storage bag 1 in this embodiment will be described with reference to Fig. 5. As shown in Fig. 5, in the method for manufacturing the storage bag 1 in this embodiment, a bag forming step (S1), a port inserting step (S2), a first heating step (S3), a first cooling step (S4), a second heating step (S5), and a second cooling step (S6) are performed in this order. Here, an example will be described in which the material of the resin sheet constituting the bag body 12 is polyethylene (melting point 127°C) and has a thickness of 0.15 mm, and the material constituting the welded portion 31 in the port portion 3 is polyethylene (melting point 129°C) and has a substantially rhombus shape.

(Bag forming process)
First, in the bag forming step (S1), a part of the periphery of the overlapped resin sheets is heated and sealed. As a result, as shown in the area D1 surrounded by the dashed line in Fig. 3, a bag body 12 is formed having a band-shaped welded area 20 where the overlapped resin sheets are welded to each other, and an opening 40 where the resin sheets are not welded to each other. The area surrounded by the welded area 20 becomes the storage section 2. In this manufacturing method, this bag forming step (S1) may be performed using an apparatus other than the manufacturing apparatus 100.

If excess size is generated on the outer periphery of the stacked resin sheets after the bag formation process (S1), the storage bag 1 may be cut to a predetermined size. A process of cutting the storage bag 1 to a predetermined size may be included before the bag formation process (S1).

(Insertion process)
In the port insertion step (S2), a port portion 3 is inserted into the opening 40. When multiple port portions 3 are inserted into the opening 40, the port portions 3 are inserted at a predetermined interval. There is no particular limit to the number of port portions 3 inserted into the opening 40. In the present embodiment, three port portions 3 are inserted into the opening 40. The port insertion step (S2) may be performed using an apparatus other than the manufacturing apparatus 100, may be performed by the support and transport section 110, or may be performed in the first heating section 101.

(First heating step)
In the first heating step (S3), the resin sheet of the opening 40 at a position spaced from each port 3 inserted inside the opening 40 is heated and welded using first heated dies 101a and 101b. When a plurality of ports 3 are inserted, the resin sheet is sealed between the ports 3.

Specifically, the control unit 150 controls the support conveying unit 110 to convey the support unit 130 to the position of the first heating unit 101. Then, the control unit 150 controls the first heated molds 101a and 101b to change from the mold open state to the mold closed state, and performs the first heating step (S3) to form the seal unit 21. At this time, the first heated molds 101a and 101b are heated in advance by the heater to a temperature higher than the melting point of the resin sheets 21a and 21b. In this manufacturing method, the temperature of the first heated molds 101a and 101b is not particularly limited, but may be, for example, Tm1 (°C), the melting point of the resin sheets 21a and 21b, or Tm1+100°C, or Tm1+10°C, or Tm1+60°C. The heating time may be, for example, 0.5 to 15 seconds, or 1 to 10 seconds. After the seal portion 21 is formed by the first heated molds 101a and 101b, the control unit 150 controls the first heated molds 101a and 101b to change from a mold closed state to a mold open state, and ends the first heating step (S3).

In the first heating step (S3), the welded portion 31 in the port portion 3 is preheated to a certain temperature. At this time, the welded portion 31 and the resin sheets 21a and 21b may or may not be welded to each other. In other words, in the first heating step (S3), the welded portion 31 may be heated to a temperature equal to or higher than the melting point of the welded portion 31.

(First cooling step)
In the first cooling step (S4), the welded portion 31, which is a part of the port portion 3 inserted into the opening 40, and the resin sheets 21a and 21b located near the welded portion 31 are cooled. As shown in FIG. 2, the welded portion 31 has two tapered ends 31a in a cross section obtained by cutting the welded portion 31 along a plane perpendicular to the insertion direction into the opening 40. The cooling dies 103a and 103b of the cooling portion 103 are shaped so that the two ends 31a are particularly cooled. That is, the cooling dies 103a and 103b are shaped so that the gap generated when the welded portion 31 is sandwiched between the cooling dies 103a and 103b is smaller than the gap generated when the welded portion 31 is sandwiched between the first heated dies 101a and 101b. In the first cooling step (S4), at least the end portion 31a of the welded portion 31 is cooled so as to prevent the generation of melt burrs in the next process, the second heating step (S5).

Specifically, the control unit 150 controls the support and transport unit 110 to transport the support unit 130 to the position of the cooling unit 103. The control unit 150 then controls the cooling molds 103a and 103b to change from an open state to a closed state. The first cooling step (S4) is preferably performed in a state in which the cooling molds 103a and 103b are maintained at a temperature of, for example, 0°C to 40°C, preferably 10°C to 20°C. By controlling the cooling molds 103a and 103b to a predetermined temperature range, the first cooling step (S4) can be performed stably. In addition, by keeping the temperature of the cooling molds 103a and 103b relatively low, the processing time in the first cooling step (S4) can be relatively short.

Here, in this manufacturing method, the first cooling step (S4) is followed immediately by the second heating step (S5). The temperature of the welded portion 31 immediately after the first cooling step (S4) is preferably 40°C or higher and Tm2 or lower, more preferably 45°C or higher and 100°C or lower, and even more preferably 50°C or higher and 80°C or lower, where Tm2 is the melting point of the port portion. In this manufacturing method, the cooling time in the first cooling step (S4) may be, for example, 0.5 to 15 seconds, or 1 to 4 seconds. After cooling at least the end portion 31a of the welded portion 31 by the cooling dies 103a and 103b, the control unit 150 controls the cooling dies 103a and 103b so that they change from a closed state to an open state, and ends the first cooling step (S4).

(Second heating step)
In the second heating step (S5), the welded portion 31, which is a part of the port portion 3 inserted inside the opening 40, and the resin sheets 21a, 21b around the welded portion 31 are heated by the second heated dies 102a, 102b, thereby welding the welded portion 31 to the resin sheets 21a, 21b. This makes it possible to reliably weld the welded portion 31 to the resin sheets 21a, 21b, and as a result, it is possible to seal the inside of the storage portion 2 at least liquid-tightly.

Specifically, the control unit 150 controls the support conveying unit 110 to convey the support unit 130 to the position of the second heating unit 102. The control unit 150 then controls the second heated molds 102a and 102b to change from an open state to a closed state. At this time, the second heated molds 102a and 102b are heated in advance by the heater to a temperature higher than the melting points of the welded portion 31 and the resin sheets 21a and 21b. In this manufacturing method, the temperature of the second heated molds 102a and 102b is not particularly limited, but may be, for example, Tm1 (°C), the melting point of the resin sheet, or may be Tm1 or more (Tm1+100°C) or less, or (Tm1+10°C) or more (Tm1+100°C). The heating time may be, for example, 0.5 to 15 seconds, or 1 to 10 seconds. By setting the above range, it is possible to prevent, for example, pinholes from occurring in the resin sheets 21a and 21b around the welded portion 31, or to prevent the resin sheets 21a and 21b around the welded portion 31 from having extremely thin portions. After the welded portion 31 is welded to the resin sheets 21a and 21b by the second heated molds 102a and 102b, the control unit 150 controls the second heated molds 102a and 102b to change from a mold closed state to a mold open state, and ends the second heating step (S5).

(Second cooling step)
After the second heating step (S5), in the second cooling step (S6), the welded portion 31 and the resin sheets 21a and 21b around the welded portion 31 are cooled. Specifically, the control unit 150 controls the support conveying unit 110 to convey the support unit 130 to the position of the cooling unit 103. Then, the control unit 150 controls the cooling molds 103a and 103b to change from the mold open state to the mold closed state. The second cooling step (S6) quickly solidifies the welded portion 31 and the resin sheets 21a and 21b that have been melted in the second heating step (S5), thereby manufacturing the storage bag 1. This allows the processing time by the manufacturing device 100 for manufacturing the storage bag 1 to be reduced. After cooling the welded portion 31 and the resin sheets 21a and 21b, the control section 150 controls the cooling dies 103a and 103b so that they change from a closed state to an open state, and the second cooling step (S6) is completed.

(Advantages of this manufacturing method)
Fig. 6 is an enlarged view showing the periphery of the welded portion 31 in the storage bag 1 of this embodiment. In Fig. 6, a molten burr 50 that may occur in a conventional storage bag is shown by a dotted line. As shown in Fig. 6, in the storage bag 1 manufactured by carrying out the first cooling step (S4) as in the present manufacturing method, the molten burr 50 (part shown by the dotted line) is not formed. On the other hand, if the second heating step (S5) is carried out immediately after the first heating step (S3) without carrying out the first cooling step (S4), the molten burr 50 may be formed.

As described above, in the manufacturing method of the storage bag 1 in this embodiment, the first cooling step (S4) is performed between the first heating step (S3) and the second heating step (S5), thereby at least cooling the end 31a of the welded portion 31 of the port portion 3 that was heated during the first heating step (S3). If the welded portion 31 is cooled excessively in the first cooling step (S4), the processing time of the second heating step (S5) may be extended, and the fusion between the welded portion 31 and the resin sheets 21a and 21b may become unstable. Therefore, it is important to moderately cool the welded portion 31 and the resin sheets 21a and 21b in the first cooling step (S4). This makes it difficult for the end protruding in the longitudinal direction of the welded portion 31 (in other words, the edge portion close to the seal portion 21 formed in the first heating step (S3)) to melt during the second heating step (S5). As a result, it is possible to make it difficult for melt burrs to occur. Therefore, the occurrence of molten flash 50 can be prevented and the storage bag 1 can be manufactured. In addition, the storage bag 1 can be manufactured with a good welding state between the port portion 3 and the resin sheets 21a and 21b. The desired performance required for the storage bag 1 can be secured and the storage bag 1 can be stably manufactured.

This manufacturing method makes it possible to manufacture the storage bag 1 suitably even if the material of the port portion 3 or the resin sheets 21a and 21b is a material that has high fluidity when heated. This manufacturing method also provides the following effects.

When the resin sheets 21a and 21b are made of a transparent or translucent material, the resin sheets 21a and 21b may crystallize to produce whitened (reduced transparency) or air bubble-filled areas. For ease of explanation, the whitened areas or air bubble-filled areas are referred to as visually noticeable defects. The occurrence of such visually noticeable defects is undesirable because the visually noticeable defects may interfere with visual inspection of the welded areas of the seal portion 21 and the port portion 3. Furthermore, the whitened areas may have reduced durability against external forces.

According to this manufacturing method, the possibility of the above-mentioned visual defects occurring can be reduced by performing the first cooling step (S4) between the first heating step (S3) and the second heating step (S5).

Other embodiments
In the above embodiment, a method using a cooling mold as a cooling means in the first heating step (S3) and the second heating step (S5) has been described, but the manufacturing method of the storage bag 1 in one aspect of the present invention is not limited to this. For example, in the manufacturing method of the storage bag 1 in another aspect of the present invention, at least the end 31a of the welded part 31 may be cooled using a cooling device or by natural cooling in the first cooling step (S4) and the second cooling step (S6). The cooling device is not particularly limited, but may be, for example, a blower that blows cold air.

In addition, in the first heating step (S3) and the second heating step (S5), heating is performed using a mold, but this is not limited to this, and in another embodiment of the method for manufacturing the storage bag 1 of the present invention, for example, heating may be performed using other contact heating means or non-contact heating means (such as a device that blows hot air or a light source that performs radiant heating).

[Modifications]
(a) In one modified example, the manufacturing apparatus 100 may include various devices for performing the bag forming step (S1) and the port inserting step (S2).

(b) In one modified example, the method for manufacturing the storage bag 1 may include a pre-cooling step between the port insertion step (S2) and the first heating step (S3) in which the cooling unit 103 is used to cool the portion of the opening 40 into which the port portion 3 is inserted. This reduces the possibility that the temperature of the welded portion 31, etc., may fluctuate due to various factors at the start of the first heating step (S3). Therefore, the processing from the first heating step (S3) to the second cooling step (S6) can be performed stably.

(c) In one modified example, the method for manufacturing the storage bag 1 does not need to include the second cooling step (S6). After the second heating step (S5), the storage bag 1 may be manufactured by natural cooling.

(d) In one modified example of the method for manufacturing the storage bag 1, the bag body 12 may have multiple openings 40, for example, an opening may also be provided below the bag body 12, and a seal portion 21 and a port portion 3 may also be provided below the bag body 12.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the above description are also included in the technical scope of the present invention.

Below, Examples 1 and 2 of the present invention will be described with reference to Tables 1 and 2, but the present invention is not limited thereto. Table 1 is a table showing the flow of the manufacturing process of the storage bag 1 in Examples 1 and 2, and Comparative Example 1.

Example 1
As Example 1, a storage bag was manufactured by carrying out the bag forming step (S1) to the second cooling step (S6) in the same manner as in the manufacturing method described in the above embodiment. Here, FIG. 7 shows the results of an experiment in which the cooling time in the first cooling step (S4) was changed from 0 seconds to 5 seconds. FIG. 7 is a graph showing the temperature change over time for each of a plurality of test pieces that were processed from the first heating step (S3) to the second cooling step (S6) by changing the cooling time in the first cooling step (S4) from 0 seconds to 5 seconds. The temperature shown in the graph of FIG. 7 was measured at the boundary between the end 31a of the welded part 31 and the seal part 21, and at the center part in the direction in which the end 31a extends (hereinafter, sometimes referred to as the temperature measurement part).

As shown in FIG. 7, when the cooling time in the first cooling step (S4) is 1 second, the temperature of the end 31a (the temperature measurement part) of the port part 3 closer to the seal part 21 is reduced to about 70°C by the first cooling step (S4). After that, the support part 130 is transported from the cooling part 103 to the second heating part 102 by the support transport part 110, and the second heating step (S5) is performed. It can be seen that the temperature of the end part 31a (the temperature measurement part) is reduced by the first cooling step (S4) as the cooling time in the first cooling step (S4) is increased to 2 seconds, 3 seconds, and 5 seconds.

In Example 1, the storage bag was manufactured with a cooling time of 1 to 5 seconds in the first cooling step (S4). No melt burrs were generated in the storage bag of Example 1. It can also be seen from the experimental results shown in FIG. 7 that, in consideration of the temperature after the first cooling step (S4), in this example, it is preferable that the cooling time in the first cooling step (S4) is 2 seconds or more.

(Comparative Example 1)
7, when the cooling time in the first cooling step (S4) is set to 0 seconds, that is, when the second heating step (S5) is performed immediately after the first heating step (S3), the second heating step (S5) is performed when the temperature of the end 31a (the temperature measurement part) of the port portion 3 closer to the seal portion 21 is about 160° C. The case in which the second heating step (S5) is performed immediately after the first heating step (S3) corresponds to the above-mentioned Comparative Example 1 shown in Table 1.

Example 2
In Example 2, a storage bag was manufactured by carrying out the bag forming step (S1) to the second cooling step (S6) in the same manner as the manufacturing method described in the above embodiment except for the following points. That is, in Example 2, natural cooling was performed without using a cooling mold in the first cooling step (S4). Here, although not shown in the figure, an experiment was performed by changing the natural cooling time in the first cooling step (S4) from 0 seconds to 10 seconds. As a result, when the natural cooling time in the first cooling step (S4) was 5 seconds or less, melt burrs were generated. In Example 2, a storage bag was manufactured with the natural cooling time in the first cooling step (S4) set to 10 seconds. In the storage bag of Example 2, the generation of melt burrs was prevented, but whitening occurred in the resin sheet.

(evaluation)
The molten bags of Example 1, Example 2, and Comparative Example 1 were evaluated by visual observation for the presence or absence of molten burrs around the welded portion 31, and the presence or absence of whitening or waviness of the resin sheets 21a and 21b around the welded portion 31.

The takt time for each of Example 1, Example 2, and Comparative Example 1 was evaluated using Example 1 as the standard (the takt time for Example 1 was considered "medium").

(Evaluation Results)
Table 2 shows the evaluation results of the manufacturing processes of the storage bags in Example 1, Example 2, and Comparative Example 1.

As shown in Table 2, no melt burrs were generated in the storage bags of Examples 1 and 2. Whitening occurred in the sealed portion of the storage bag of Example 2. Furthermore, the takt time of Example 2 was longer than that of Example 1. In Comparative Example 1, the takt time was relatively short, but melt burrs were generated.

1: Storage bag 2: Storage section 3: Port section 12 Bag body 20: Welding area 31: Welded section 31a: End (edge of the port section on the side closer to the resin sheet welded in the first heating step) 40: Opening 100: Manufacturing device 101: First heating section 101a, 101b: First heating mold (heating mold) 102: Second heating section 102a, 102b: Second heating mold (heating mold) 103: Cooling section 103a, 103b: Cooling mold (cooling mold)

Claims (4)

A method for manufacturing a storage bag having a bag body having a storage portion for storing a storage object and a port portion for discharging the storage object in the storage portion to an outside, comprising:
a bag forming step of forming the bag body having an opening and a band-shaped welded region in which the resin sheets are welded to each other by sealing a part of the peripheral edge of the overlapped resin sheets;
an insertion step of inserting the port part having a welded part into the opening defined by the welded region;
a first heating step of welding the resin sheet at the opening at a position separated from the welded portion inserted into the opening using a heating mold;
A first cooling step of cooling at least an edge of the welded portion that is close to the resin sheet welded in the first heating step in order to prevent a part of the welded portion from seeping out and causing a molten burr;
a second heating step of heating the welded portion inserted into the opening and the resin sheet around the periphery of the welded portion using a heating mold to weld the welded portion to the resin sheet;
a second cooling step of cooling the resin sheet at the welded portion and at a periphery of the welded portion;
in that order ,
The first cooling step is performed between the first heating step and the second heating step,
the port portion has a shape in which, in a cross section obtained by cutting the welded portion along a plane perpendicular to a direction of insertion into the opening, the welded portion has a long axis direction and has tapered end portions located at both ends in the long axis direction, the end portions being the edge portions;
In the first heating step, the welded portion is preheated,
A method for manufacturing a storage bag, in which the temperature of the welded portion immediately after the first cooling step is in the temperature range of 40°C or higher and Tm2 or lower, where Tm2 is the melting point of the port portion (°C), and the second heating step is performed on the welded portion in this temperature range. The method for manufacturing a storage bag according to claim 1, characterized in that in the first cooling step, the welded portion and the resin sheet around the periphery of the welded portion are cooled. In the first cooling step, the welded portion is cooled using a cooling mold;
The method for manufacturing a storage bag according to claim 1 or 2, characterized in that the cooling mold has a smaller gap between the welded portion and the heating mold used in the first heating step. The method for manufacturing a storage bag according to claim 3, characterized in that in the first cooling step, cooling is performed while the cooling mold is maintained at a temperature between 0°C and 40°C.

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