JP2017176543A - Liquid bag and method for manufacturing liquid bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid bag capable of preventing a stored liquid from being leaked outward, and a method of manufacturing the same.SOLUTION: A liquid bag 1 comprises a bag body 11 which is configured by heat-sealing soft sheet materials 10 together and which has a storage part 111 capable of storing a liquid 100 inside a sealed part 2. Additionally, the sealed part 2 has a gradual increase part 221 which is provided between the storage part 111 and the sealed part and in which the thickness of the sheet material 10 gradually increases toward the inside of the bag body 11.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid bag and a method for manufacturing a liquid bag.

  For example, a liquid bag for storing liquids such as physiological saline, electrolyte solution, Ringer's solution, high-calorie infusion solution, glucose solution, water for injection, peritoneal dialysis solution, and oral nutrient is known (for example, see Patent Document 1).

  The liquid bag described in Patent Document 1 stores liquids such as artificial kidney replenishers, intravenous infusion preparations, liquid nutrient solutions, etc., and is formed by forming a sheet material made of a resin material into a bag shape. is there. Such a liquid bag is formed, for example, by forming a sheet material into a cylindrical shape and joining both ends thereof by heat fusion. That is, the fusion part is formed in the both ends of the liquid bag.

  Further, the heat fusion is performed by stacking the sheet material between the upper mold and the lower mold, and pressing the overlapped portion between the flat press surfaces of the upper mold and the lower mold. This is done by heating.

  However, when the external force is applied to the liquid bag, stress is concentrated at the boundary portion between the fused portion and the unfused portion that has not been fused. Depending on this degree, there is a possibility that the fused portion peels at a stretch, or the sheet material is torn and broken. As a result, there is a possibility that the liquid in the liquid bag leaks to the outside.

No. 2007-125206

  The objective of this invention is providing the manufacturing method of the liquid bag which can prevent the stored liquid from leaking outside, and a liquid bag.

Such an object is achieved by the present inventions (1) to (11) below.
(1) A liquid bag comprising a bag body having a storage portion capable of storing a liquid inside the fusion portion, wherein the soft sheet material is thermally fused,
The liquid bag is characterized in that the fusion part is provided at a boundary part with the storage part, and has a gradually increasing part in which the thickness of the sheet material gradually increases toward the inside of the bag body.

(2) The fusion part is provided on the inner side of the first fusion part and the first fusion part and has a second fusion strength lower than that of the first fusion part. Having a wearing part,
The gradually increasing portion is the liquid bag according to (1), wherein the gradually increasing portion is provided in the second fusion portion.

  (3) The liquid bag according to (1) or (2), wherein in the gradually increasing portion, the fusion strength of the sheet material gradually decreases toward the inside of the bag body.

(4) When the difference between the maximum thickness and the minimum thickness of the gradually increasing portion is a, and the length of the gradually increasing portion from the inside to the outside of the bag body is b,
The liquid bag according to any one of (1) to (3), wherein the ratio a / b satisfies a relationship of 0.05 or more and 0.25 or less.

  (5) The liquid bag according to any one of (1) to (4), wherein a gradually increasing rate of the thickness of the gradually increasing portion is constant.

  (6) The liquid bag according to any one of (1) to (5), wherein the thickness of the sheet material is 0.2 mm or more and 0.8 mm or less.

  (7) The liquid bag according to any one of (1) to (6), wherein the sheet material includes polyolefin as a main material.

(8) The bag body has a flat shape as a whole, and the width of the storage portion has a reduced width portion that gradually narrows from the inside to the outside of the bag body,
The said gradually increasing part is a liquid bag in any one of said (1) thru | or (7) provided in the part which faces the said reduced width part.

(9) A manufacturing method for manufacturing a liquid bag including a bag body formed of a soft sheet material,
The sheet material is heat-sealed to form a fusion part, and a heat-fusing step of forming a storage part capable of containing a liquid inside the fusion part,
In the heat sealing step, a gradually increasing portion is formed at a boundary portion with the storage portion, and the thickness of the sheet material gradually increases toward the inside of the bag body. Production method.

(10) In the thermal fusion process, the first and second molds having a press surface for holding the sheet materials and heating in the sandwiched state are used,
An inclined surface that is inclined in a direction away from the other die is formed on the press surface of one of the first die and the second die.
The method for manufacturing a liquid bag according to (9), wherein the gradually increasing portion is formed by the inclined surface.

(11) The fusing temperature in the heat fusing step is 180 ° C. or higher and 240 ° C. or lower,
The method for producing a liquid bag according to (9) or (10), wherein the time for heating the sheet material in the heat fusion step is 2 seconds or more and 30 seconds or less.

  According to the present invention, when the gradually increasing portion is formed in the fusion portion, the fusion strength of the gradually increasing portion becomes weaker than the fusion strength of the portion other than the gradually increasing portion of the fusion portion. For this reason, in the fused portion, the portion on the storage portion side becomes a weakly fused portion with low fusion strength, and the portion on the opposite side to the accommodation portion of the weakly fused portion becomes a strongly fused portion with high fusion strength.

  When an external force is applied to the bag body to compress the storage part, stress concentrates on the boundary part between the storage part and the fusion part. In such a case, the weak fusion part peels off in the present invention. By doing so, the stress concentration is relaxed. That is, in the present invention, the stress concentration can be relieved by deliberately peeling the weakly fused portion, and it is possible to prevent the sheet material from being peeled off or the sheet material from being broken. As a result, it is possible to prevent the entire fused portion from being broken and to prevent the liquid in the storage portion from leaking to the outside.

FIG. 1 is a front view of a liquid bag of the present invention. 2A and 2B are cross-sectional views taken along line AA in FIG. 1, where FIG. 2A is a diagram illustrating a natural state, and FIG. 2B is a diagram illustrating a state where a weakly fused portion is peeled off. 3A and 3B are cross-sectional views for explaining the method for manufacturing a liquid bag according to the present invention, in which FIG. 3A is a view showing an arrangement step, and FIG. 3B is a view showing a heat fusion step. FIG. 4 is a side view showing a test piece on which a tensile test is performed in the example. FIG. 5 is a cross-sectional view illustrating a liquid bag in which a drop test is performed in the example. 6A and 6B are cross-sectional views showing a fusion part of a conventional liquid bag, in which FIG. 6A shows a natural state, and FIG. 6B shows a state where the fusion part is broken.

  Hereinafter, a liquid bag and a liquid bag manufacturing method of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Embodiment>
FIG. 1 is a front view of a liquid bag of the present invention. 2A and 2B are cross-sectional views taken along line AA in FIG. 1, where FIG. 2A is a diagram illustrating a natural state, and FIG. 2B is a diagram illustrating a state where a weakly fused portion is peeled off. 3A and 3B are cross-sectional views for explaining the method for manufacturing a liquid bag according to the present invention, in which FIG. 3A is a view showing an arrangement step, and FIG. 3B is a view showing a heat fusion step. FIG. 4 is a side view showing a test piece on which a tensile test is performed in the example. FIG. 5 is a cross-sectional view illustrating a liquid bag in which a drop test is performed in the example. 6A and 6B are cross-sectional views showing a fusion part of a conventional liquid bag, in which FIG. 6A shows a natural state, and FIG. 6B shows a state where the fusion part is broken.

  In the following, for convenience of explanation, the upper side of FIGS. 1 to 6 is referred to as “upper” or “upper”, and the lower side is referred to as “lower” or “lower”.

  As shown in FIG. 1, the liquid bag 1 is formed by heat-sealing soft sheet materials, and has a storage portion 111 (storage space) that can store a liquid inside the fusion portion 2. A bag-shaped bag body 11 and a mouth 12 and a mouth 13 provided on the bag body 11 are provided. In addition, the liquid bag 1 shall contain peritoneal dialysis liquid as an example.

Hereinafter, each part will be described.
The bag body 11 is obtained by, for example, a method of forming a sheet material 10 made of a soft material into a cylindrical shape and fusing both ends thereof, a method of fusing edges of two sheet materials 10, and the like. In the liquid bag 1, the bag body 11 is formed by a method in which a sheet material 10 made of a soft material is formed into a cylindrical shape, and the portions where the sheet material 10 overlaps are heat-sealed at both ends thereof. For this reason, in the bag main body 11, the band-shaped melt | fusion part 2 (heat-fusion part) is formed in the edge part of an upper end and a lower end.

  The bag body 11 has a flat shape, and has a substantially rectangular shape in plan view. Further, at both ends of the bag body 11, a reduced width portion 112 is formed that gradually decreases in width as the width W of the storage portion 111 (the maximum width in a state where no liquid is stored) goes to both ends. The fused portion 2 has a curved shape along the reduced width portion 112 at the corner of the bag body 11.

  The storage unit 111 is partitioned by a strip-shaped partition unit 23 formed by fusing the sheet materials 10 together. As a result, the storage unit 111 is divided into a storage unit 113 and a storage unit 114 that are not in communication with each other. Moreover, the partition part 23 is lower in fusion strength than a strong fusion part 21 described later, and is broken by applying pressure to the bag body 11 so that the accommodation part 113 and the accommodation part 114 can communicate with each other.

  The storage part 113 and the storage part 114 are arranged side by side from the lower side in FIG. The storage unit 113 has a larger volume than the storage unit 114. As the liquid 100 stored in the storage unit 113, a liquid whose main component is glucose or the like can be used. In addition, as the liquid 101 stored in the storage unit 114, for example, a liquid containing sodium chloride, sodium lactate, or the like as a main component can be used. As described above, the liquid 100 and the liquid 101 are mixed by causing the storage portion 113 and the storage portion 114 to communicate with each other.

  Although it does not specifically limit as thickness of the sheet material 10, It is preferable that they are 0.2 mm or more and 0.8 mm or less, and it is more preferable that they are 0.3 mm or more and 0.7 mm or less. If the sheet material 10 is too thick, it takes a relatively long time to be fused by thermal fusion. On the other hand, if the sheet material 10 is too thin, it may be difficult to sufficiently secure the strength of the fused portion 2 formed by heat fusion.

  Although it does not specifically limit as a constituent material of the bag main body 11, Soft synthetic resin with moderate heat resistance can be used. Examples of the soft synthetic resin include polyolefin (eg, polyethylene, polypropylene, polybutadiene, ethylene-propylene copolymer, a mixture containing polyolefin such as a mixture of polypropylene and polyethylene or polybutene), and a partially cross-linked product thereof, ethylene-acetic acid. Vinyl copolymer (EVA), polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), soft vinyl chloride resin, polyvinyl acetate, polyvinylidene chloride, silicone, polyurethane, polyamide elastomer, polyester elastomer, styrene / ethylene / butylene / styrene copolymer Various thermoplastic elastomers such as styrene elastomers such as polymers, or any combination thereof (blend resin, polymer elastomer) Lee, and a laminate, etc.) and the like.

  The mouth portion 12 is formed of a cylindrical member and is fixed to the edge portion of the bag body 11. The mouth 12 has one end facing the bag body 11 and the other end positioned outside the bag body 11. Thereby, the inside and outside of the bag main body 11 can be communicated.

  As shown in FIG. 1, the mouth portion 12 includes a cylindrical portion 121 that forms a cylinder, and a fixing portion 122 that is formed to protrude from the outer peripheral portion of the cylindrical portion 121.

  The cylindrical portion 121 functions as a flow path through which the liquid passes. Thereby, a liquid can be discharged | emitted from the bag main body 11 outside, or a liquid can be inject | poured into the bag main body 11. FIG.

  A flat fixing portion 122 is formed on the outer peripheral portion of the base end of the cylindrical portion 121. The fixing portion 122 is a portion that is fixed to the sheet material 10 while being sandwiched between the sheet materials 10.

  In the unused state, the cylindrical portion 121 is fitted with a cap 15 and the storage portion 111 is sealed in a liquid-tight manner.

  The mouth portion 13 is formed of a tubular member having an inner diameter and an outer diameter that are smaller than those of the mouth portion 12. Further, the mouth portion 13 is fixed in the vicinity of the edge portion to which the mouth portion 12 of the bag body 11 is fixed. One end portion of the mouth portion 13 is provided so as to protrude into the bag body 11, and the other end portion is located outside the bag body 11. Thereby, the inside and outside of the bag main body 11 can be communicated.

  In addition, the mouth portion 13 includes a tubular portion 131 having a tubular shape, and a fixing portion 132 that is formed to protrude from the outer peripheral portion of the tubular portion 131.

  The tubular part 131 functions as a flow path through which the liquid passes. Thereby, a liquid can be discharged | emitted from the bag main body 11 outside, or a liquid can be inject | poured into the bag main body 11. FIG.

  A flat fixing portion 132 is formed in the middle of the tubular portion 131 in the longitudinal direction. The fixing portion 132 is a portion that is fixed to the sheet material 10 while being sandwiched between the sheet materials 10.

  A flexible tube 14 is connected to the end located outside the mouth portion 13. Thereby, the liquid bag 1 can be connected to other medical devices or the like via the tube 14. In addition, the end portion located inside the mouth portion 13 has a breaking member that can be folded and broken to open the end portion and allow the bag body 11 and the tube 14 to communicate with each other.

  Examples of the constituent material of the mouth portion 12 and the mouth portion 13 include various thermoplastic resins, and various curable resins such as a thermosetting resin and a photocurable resin. Specifically, for example, polyolefin such as polyethylene, polypropylene, ethylene-propylene copolymer, polyvinyl chloride, polystyrene, polyamide, polyimide, polycarbonate, poly- (4-methylpentene-1), ionomer, acrylic resin, Polymethyl methacrylate, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene copolymer (AS resin), butadiene-styrene copolymer, polyethylene terephthalate (PET), polyester such as polybutylene terephthalate (PBT) , Polyether, polyetherketone (PEK), polyetheretherketone (PEEK), polyetherimide, polyacetal (POM), polyphenylene oxide, polysulfone, poly -Tersulfone, polyphenylene sulfide, polyarylate, aromatic polyester (liquid crystal polymer), polytetrafluoroethylene, polyvinylidene fluoride, other fluororesin, epoxy resin, phenol resin, urea resin, melamine resin, silicone resin, polyurethane, etc. And a copolymer, a blend, a polymer alloy, and the like, and one or more of them can be used in combination.

  When the liquid bag 1 is conveyed, the liquid bag 1 is folded at the partition portion 23 to be folded in half. Moreover, when folding, as shown in FIG. 5, it is preferable to fold so that the tube 14 may be pinched inside.

  Now, in the liquid bag 1, in the state where the liquid 100 is stored in the storage portion 113 and the liquid 101 is stored in the storage portion 114, for example, when an external force is applied to the bag body 11 during transportation or the like, The part 2 may peel off or the sheet material may break, and the liquid 100 or the liquid 101 may leak to the outside. However, the liquid bag 1 has a configuration effective for preventing or suppressing this.

This will be described below.
2A and 2B are cross-sectional views taken along line AA in FIG. As shown in FIG. 2A, the fusion part 2 is a part where the part where the sheet material 10 is overlapped is thermally fused, and the part from the boundary with the storage part 111 to the outer edge of the bag body 11 is fused. It is part 2.

  The fusion part 2 includes a strong fusion part 21 (first fusion part) having a relatively high fusion strength, and a fusion strength (average fusion in the surface direction of the sheet material 10) than the strong fusion part 21. And a weakly fused portion 22 (second fused portion) having a low (bonding strength). In the present embodiment, the strong fusion portion 21 and the weak fusion portion 22 are formed over the entire length in the longitudinal direction of the fusion portion 2.

  The strong fusion part 21 is located on the outer edge side of the sheet material 10 in the fusion part 2, and the weak fusion part 22 is located on the inner side of the bag body 11, that is, on the storage part 111 side in the fusion part 2. doing.

  The length L21 of the sheet material 10 (the average length from the inner side to the outer side of the bag body 11) of the strongly fused portion 21 is not particularly limited, but is preferably 3 mm or more and 30 mm or less, preferably 5 mm or more and 25 mm. The following is more preferable. Further, the length L22 (average length from the inside to the outside of the bag body 11) of the sheet material 10 of the weakly fused portion 22 is not particularly limited, but is preferably 0.1 mm or more and 20 mm or less. More preferably, it is 5 mm or more and 10 mm or less.

  The ratio L22 / L21 between the length L21 and the length L22 may be constant along the longitudinal direction of the fused portion 2 or may have different portions. The ratio L22 / L21 is preferably 0.01 or more and 2.5 or less. Thereby, the liquid leak mentioned later can be prevented or suppressed.

  The thickness of the strongly fused portion 21 is constant along the surface direction of the sheet material 10. The weakly fused portion 22 has a gradually increasing portion 221 whose thickness gradually increases toward the inside of the bag body 11, that is, toward the storage portion 111. The gradually increasing portion 221 is formed by a liquid bag manufacturing method to be described later, and becomes a weakly fused portion 22 at that time.

  When the difference between the maximum thickness and the minimum thickness of the gradually increasing portion 221 is a and the length of the sheet material of the gradually increasing portion 221 from the inside to the outside of the bag body 11 is b, the ratio a / b is 0.05. As mentioned above, it is preferable to satisfy the relationship which is 0.25 or less, and it is more preferable to satisfy the relationship which is 0.07 or more and 0.23 or less. Thereby, the liquid leak mentioned later can be prevented or suppressed. In the present embodiment, the lengths L22 and b are the same value.

  Here, as shown in FIG. 6 (a), when an external force is applied so that the liquid bag 1 'is compressed from a natural state where no external force is applied to the conventional liquid bag 1', the stress is fused. It concentrates on the boundary part between 2 'and storage part 111'. Depending on the degree, the fusing strength, and the like, as shown in FIG. 6B, the sheet material of the fusing part 2 'may break and the liquid inside may leak. Although not shown, the sheet material at the fused portion 2 ′ may be peeled off due to the stress concentration. This is one of the reasons that the fusion strength of the fusion part 2 'is constant. If the fusion strength is constant, if the fusion part 2 ′ begins to peel from the inside, it will peel to the outside at once.

  In the present invention, when an external force is applied from the natural state shown in FIG. 2A, stress concentrates on the weakly fused portion 22 (gradual increase portion 221) facing the storage portion 111 as shown in FIG. 2B. To do. At this time, the sheet material 10 is peeled off at the weakly fused portion 22. Thereby, it can relieve | moderate that an excessive stress concentrates on the melt | fusion part 2. FIG. That is, in the liquid bag 1, the excessive stress concentration is eased by deliberately peeling the sheet material 10 at the weakly fused portion 22, and the sheet material 10 is peeled off to the strong fused portion 21. Can be prevented. As a result, it is possible to prevent the entire fused portion 2 from being broken or peeled off, and to prevent the liquid 100 in the storage portion 111 from leaking to the outside.

  In particular, the reduced width portion 112 is a portion where the stress concentration is likely to occur. In the liquid bag 1, since the strongly fused portion 21 and the weakly fused portion 22 are formed in the reduced width portion 112, the liquid 100 can be prevented or suppressed from leaking to the outside in the reduced width portion 112. it can.

  Further, in the weak fusion part 22, the fusion strength gradually decreases toward the storage part 111. That is, in the weak fusion part 22, the fusion strength is the lowest at the part facing the storage part 111, and the fusion strength increases from the storage part 111 to the outside. According to such a configuration, when the sheet material 10 peels at the weakly fused portion 22, the sheet material 10 is gradually peeled off. Therefore, it can prevent more reliably that the weak melt | fusion part 22 peels at a stretch and peels to the strong melt | fusion part 21 at a stretch.

  In the present embodiment, the rate of gradual increase in the thickness of the gradual increase portion 221 is constant. For this reason, in the weak melt | fusion part 22, the melt | fusion intensity | strength is low in the fixed ratio toward the outer side. That is, in the weak fusion part 22, the gradual decrease rate of the fusion strength from the inner side to the outer side of the bag body 11 is constant. Thereby, when the sheet material 10 of the weak melt | fusion part 22 peels, it peels stably and can exhibit the said effect more reliably.

  Next, the manufacturing method of the liquid bag 1 (the manufacturing method of the liquid bag of this invention) is demonstrated using FIG.

  3A and 3B are cross-sectional views for explaining the method for manufacturing a liquid bag according to the present invention, in which FIG. 3A is a view showing an arrangement step, and FIG. 3B is a view showing a heat fusion step.

  The manufacturing method of the liquid bag 1 has a [1] arrangement | positioning process, a [2] heat-fusion process, and a [3] cooling process.

  Hereinafter, prior to explaining the manufacturing method of the liquid bag 1, the thermal fusion apparatus 3 used for this manufacturing method is demonstrated.

  As shown in FIGS. 3A and 3B, the thermal fusion apparatus 3 includes a first die 31 and a second die 32 that sandwich the sheet material 10 and perform thermal fusion in the sandwiched state. Have.

  The 1st type | mold 31 is comprised with the metal mold | die which makes | forms the block shape in which the heater was incorporated inside. The first mold 31 is disposed above the second mold 32 and is configured to be movable up and down. Further, the press surface 310 which is the lower surface of the first die 31 is a flat flat surface 311 facing the second die 32 and an inclination inclined with respect to the flat surface 311 in a direction away from the second die 32. Surface 312. The flat surface 311 is located on the left side in FIG. 3A, and the inclined surface 312 is located on the right side in FIG.

  Note that the inclination angle θ of the inclined surface 312 with respect to the flat surface 311, the length L 1 in the direction parallel to the flat surface 311 of the inclined surface 312 (left and right direction in FIG. 3), and the direction orthogonal to the flat surface 311 of the inclined surface 312. The length L <b> 2 can be appropriately set according to the shape of the gradually increasing portion 221.

  The second mold 32 is composed of a block body containing silicon. The press surface 320 that is the upper surface of the second die 32 is configured by a flat flat surface 321. The flat surface 321 is a portion where the sheet material 10 before being fused is disposed.

Hereinafter, the manufacturing method of the liquid bag 1 using this heat sealing | fusion apparatus 3 is demonstrated.
[1] Arrangement Step First, the sheet material 10 formed into a cylindrical shape is placed on the flat surface 321 of the second mold 32. At this time, the portion to be the fused portion 2 can be accurately arranged between the first die 31 and the second die 32 by a positioning portion (for example, a protrusion) of the second die 32 (not shown). it can.

  Although not shown, by arranging the mouth portion 12 between the sheet materials 10, the mouth portion 12 is fixed to the bag body 11 through the following steps.

[2] Thermal Fusion Process Next, as shown in FIGS. 3A and 3B, the heated first mold 31 is pressed against the sheet material 10 on the second mold 32. Thereby, it heats in the clamping state by which the overlapping part of the sheet | seat material 10 was clamped, and the melt | fusion part 2 is formed.

  At this time, first, as shown in FIG. 3A, in the sheet material 10, a portion pressed by the flat surface 311 of the first mold 31 is melted or softened. Then, as shown in FIG. 3B, the melted or softened portion of the sheet material 10 has a flat surface 321 of the second mold 32 and a first mold 31 as indicated by arrows in FIG. Move to the gap G between the inclined surface 312 and the inclined surface 312. The moved portion becomes a gradually increasing portion 221 through a cooling process described later.

  Further, when the heating by the first mold 31 is further continued in the state shown in FIG. 3B, both the sheet materials 10 stacked one above the other are melted or softened.

  Moreover, it is preferable that heating temperature is 180 degreeC or more and 240 degrees C or less, and it is more preferable that it is 190 degreeC or more and 230 degrees C or less. Thereby, although depending on the constituent material and thickness of the sheet material 10, the sheet material 10 can be reliably melted, and the fused portion 2 can be formed in a relatively short time.

  The time for heating the sheet material 10 by the first mold 31, that is, the time for pressing the first mold 31 against the sheet material 10 is preferably 2.0 seconds or more and 6.0 seconds or less, and 3.0 More preferably, it is not less than seconds and not more than 5.0 seconds. Thereby, the sheet | seat material 10 can be fuse | melted reliably. If the heating time is too short, although depending on the temperature of the first mold 31, the sheet material 10 may be insufficiently melted or softened. On the other hand, if the heating time is too long, the time spent for the heat-sealing process becomes relatively long, and the productivity tends to decrease.

  Moreover, as shown in FIG.3 (b), it is preferable that the pressure P when the sheet | seat material 10 is clamped is 0.05 Pa or more and 2.00 Pa or less, and is 0.10 Pa or more and 1.00 Pa or less. More preferably. Thereby, the melt | fusion intensity | strength of the melt | fusion part 2 can be raised.

  When the pressure is too high, depending on the thickness of the sheet material 10, the thickness of the obtained fused portion 2 tends to be thin. On the other hand, if the pressure is too weak, the fusion strength of the fusion part 2 may be insufficient.

[3] Cooling step Next, the melted or softened portion of the sheet material 10 is cooled. In this embodiment, cooling is performed by bringing a metal plate at room temperature into contact.

  The cooling temperature in this step is preferably 50 ° C. or higher and 100 ° C. or lower, and more preferably 60 ° C. or higher and 90 ° C. or lower. Thereby, the melt | fusion intensity | strength of the melt | fusion part 2 is fully securable.

  The cooling time in this step is preferably 3.0 seconds or more and 7.0 seconds or less, and more preferably 4.0 seconds or more and 6.0 seconds or less. The fusion | melting part 2 can be cooled reliably.

  In this cooling process, cooling may be performed by blowing cool air with a cooling device (not shown), or cooling may be performed by natural cooling.

  Then, the liquid 100 is supplied to the storage unit 113 and the liquid 101 is supplied to the storage unit 114, and the supply port is fused.

  In the liquid bag 1 obtained through the steps [1] to [3] as described above, the gradually increasing portion 221 as described above is formed. Further, the gradually increasing portion 221 is thicker than the portion other than the gradually increasing portion 221 in the fused portion 2. For this reason, the amount of heat transferred in the heat fusion process is relatively small. Therefore, the portion where the gradually increasing portion 221 is formed becomes the weak fusion portion 22 having a relatively low fusion strength, and the other portion becomes the strong fusion portion 21 having a fusion strength higher than that of the weak fusion portion 22.

  Further, as the thickness of the gradually increasing portion 221 increases or decreases, the fusion strength of the weakly fused portion 22 also changes. Of the gradually increasing portion 221, the portion having a relatively thin thickness has a relatively high fusion strength even in the weakly fused portion 22, and the portion having a relatively thick thickness is fused in the weakly fused portion 22. The strength is relatively weak. For this reason, it is possible to obtain the weakly fused portion 22 having a relatively weak fusion strength on the storage portion 111 side and gradually increasing the fusion strength toward the side opposite to the storage portion 111.

  According to such a liquid bag 1, as described above, it is possible to prevent or suppress the entire fusion part 2 from being broken or peeled off, and to prevent the liquid 100 in the storage part 111 from leaking to the outside. can do.

  As mentioned above, although the manufacturing method of the liquid bag and liquid bag of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is the arbitrary which has the same function. It can be replaced with a constituent or any process. Moreover, other arbitrary structures and processes may be added to the present invention.

  In the above-described embodiment, the bag body 11 is described as containing a peritoneal dialysis solution. However, the present invention is not limited to this. For example, physiological saline, electrolyte solution, Ringer's solution, high-calorie infusion solution, glucose solution In addition, water for injection, oral nutrients, and the like may be stored.

Hereinafter, based on an Example, this invention is demonstrated more concretely.
1. 1. Examination of liquid bag having fusion part in which gradually increasing part is formed 1-1. Formation of liquid bag [Example 1]
[1] First, a sheet material made of polypropylene having a thickness of 300 μm and formed into a cylindrical shape was prepared.

  [2] Next, by using the heat fusion apparatus 3 shown in FIGS. 3A and 3B, the cylindrical end portions are fused by heat fusion, and then cooled, thereby performing the first embodiment. A liquid bag was obtained.

  In addition, as the first mold 31, the one having the inclined surface 312 having a length L1 of 3.0 mm and the inclined surface having a length L2 of 0.5 mm was used. The gradually increasing portion in the fused portion of the obtained liquid bag has a difference between the maximum thickness and the minimum thickness as a, and the length of the gradually increasing portion in the surface direction (the length from the inner side to the outer side of the bag body 11). ) Is b, the ratio a / b is 0.17 (see FIG. 2A). Further, the ratio of the lengths of the strong fusion part and the weak fusion part (the length in the width direction of the belt-like fusion part) was 3: 1.

  The liquid bag of Example 1 was obtained by setting the heating temperature at the time of fusing to 238.0 ° C., the heating time and the pressurizing time to 3.5 seconds, the cooling temperature to 20 ° C., and the cooling time to 3.00 seconds. It was.

[Example 2]
In the step [2], the first mold 31 is the same as in Example 1 except that the length L1 of the inclined surface 312 is 3.0 mm and the length L2 of the inclined surface is 0.2 mm. Similarly, the liquid bag of Example 2 was obtained. In the liquid bag of Example 2, the ratio a / b was 0.07.

[Example 3]
In the step [2], the first mold 31 is the same as in Example 1 except that the length L1 of the inclined surface 312 is 3.0 mm and the length L2 of the inclined surface is 0.7 mm. Similarly, a liquid bag of Example 3 was obtained. In the liquid bag of Example 3, the ratio a / b was 0.23.

[Comparative Example 1]
Hereinafter, based on an Example, this invention is demonstrated more concretely.
1. 1. Examination of liquid bag having fusion part in which gradually increasing part is formed 1-1. Formation of liquid bag [1] First, a sheet material made of polypropylene having a thickness of 300 μm was formed into a cylindrical shape.

  [2] Next, fused portions having a width of 3.0 mm were formed at both ends of the cylinder using an upper mold and a lower mold having parallel clamping surfaces.

The liquid bag of Comparative Example 1 was obtained by setting the heating temperature at the time of fusing to 238.0 ° C., the heating time and the pressurizing time to 3.5 seconds, the cooling temperature to 20 ° C., and the cooling time to 3.00 seconds. It was.
And the liquid bag of each Example and the comparative example was evaluated with the following method.

<Tensile test>
First, as shown in FIG. 4, the sheet material 10 including the fused portion 2 was cut into a 10 mm square, and a test piece in which the two sheet materials 10 were fused was created. Using this test piece, an autograph precision universal testing machine (manufactured by Shimadzu Corp., Auto Club AGS-J) was subjected to a 180 ° tensile test in which both ends of each sheet material were pulled in opposite directions with a tensile force of 25 N for 10 seconds. went. At this time, the liquid bags of Examples 1 to 3 were pulled from the weak fusion part 22 side. Then, the length of the peeled portion, that is, the maximum length from the peeled end portion to the fused portion was measured.

<Drop test>
As shown in FIG. 5, a total of four liquid bags are folded and stored in a box 200 having a partition 201 at the center and two storage spaces S, two in each storage space S. And sealed. In each storage space S, two liquid bags 1 are stacked and stored. Then, in this state, the box body is dropped in the direction of the arrow in FIG. 5 with the thickness direction of the liquid bag 1 being the vertical direction.

  Five box bodies 200 storing such four liquid bags 1 were prepared. Then, it is verified whether or not liquid leakage has occurred in a total of five liquid bags in which other liquid bags are stacked on the lower side in the vertical direction, that is, on the upper side in the storage space S among the total twenty liquid bags 1. The number of liquid leaks was measured.

  In addition, the temperature of the liquid bag was 5 ° C., the height of dropping was 80 cm, the box was dropped 10 times for each box 200, and the number of liquid bags in which liquid leakage due to the fracture of the fused portion 2 occurred was measured. .

  Table 1 below shows the evaluation results of the liquid bags of Examples and Comparative Examples obtained as described above.

  As shown in Table 1, in the liquid bag of each example, liquid leakage due to breakage or peeling of the fused portion is less likely to occur than in the liquid bag of the comparative example. Further, in the tensile test, the longer the peeled length, the more the stress concentration when an impact is applied can be reduced.

  In the present invention, it has been confirmed that, as long as the fusion part has a gradually increasing part, it is possible to obtain something superior to the existing liquid bag.

  In the above description, the present invention has been described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Needless to say.

DESCRIPTION OF SYMBOLS 1 Liquid bag 1 'Liquid bag 10 Sheet material 11 Bag main body 111 Storage part 111' Storage part 112 Reduced width part 113 Storage part 114 Storage part 12 Mouth part 121 Cylindrical part 122 Fixing part 13 Mouth part 131 Tubular part 132 Fixed part 14 Tube 15 Cap 2 Fusion part 2 ′ Fusion part 21 Strong fusion part 22 Weak fusion part 221 Graduation part 23 Partition part 3 Thermal fusion device 31 First die 310 Press surface 311 Flat surface 312 Inclined surface 32 Second Mold 320 Press surface 321 Flat surface 100 Liquid 101 Liquid 200 Box 201 Partition part G Gap P Pressure S Storage space W Width θ Inclination angle

Claims (11)

It is a liquid bag comprising a bag body having a storage part capable of storing liquid inside the fusion part, wherein the soft sheet material is heat-sealed.
The liquid bag is characterized in that the fusion part is provided at a boundary part with the storage part, and has a gradually increasing part in which the thickness of the sheet material gradually increases toward the inside of the bag body. The fusion part includes a first fusion part and a second fusion part provided on the inner side of the first fusion part and having a fusion strength lower than that of the first fusion part. Have
The liquid bag according to claim 1, wherein the gradually increasing portion is provided in the second fusion portion.   3. The liquid bag according to claim 1, wherein in the gradually increasing portion, the fusion strength of the sheet material gradually decreases toward the inside of the bag body. When the difference between the maximum thickness and the minimum thickness of the gradually increasing portion is a, and the length of the gradually increasing portion from the inside to the outside of the bag body is b,
The liquid bag according to claim 1, wherein the ratio a / b satisfies a relationship of 0.05 or more and 0.25 or less.   The liquid bag according to claim 1, wherein a gradually increasing rate of the thickness of the gradually increasing portion is constant.   The liquid bag according to any one of claims 1 to 5, wherein a thickness of the sheet material is 0.2 mm or more and 0.8 mm or less.   The liquid bag according to claim 1, wherein the sheet material includes polyolefin as a main material. The bag body has a flat shape as a whole, and the width of the storage portion has a reduced width portion that gradually narrows from the inside to the outside of the bag body,
The liquid bag according to claim 1, wherein the gradually increasing portion is provided at a portion facing the reduced width portion. A manufacturing method for manufacturing a liquid bag comprising a bag body made of a soft sheet material and having a bag shape,
The sheet material is heat-sealed to form a fusion part, and a heat-fusing step of forming a storage part capable of containing a liquid inside the fusion part,
In the heat sealing step, a gradually increasing portion is formed at a boundary portion with the storage portion, and the thickness of the sheet material gradually increases toward the inside of the bag body. Production method. In the thermal fusion process, the sheet material is sandwiched between the first mold and the second mold having a press surface for heating in the sandwiched state,
An inclined surface that is inclined in a direction away from the other die is formed on the press surface of one of the first die and the second die.
The method for manufacturing a liquid bag according to claim 9, wherein the gradually increasing portion is formed by the inclined surface. The fusing temperature in the heat fusing step is 180 ° C. or higher and 240 ° C. or lower,
The method for manufacturing a liquid bag according to claim 9 or 10, wherein the time for heating the sheet material in the heat-sealing step is 2 seconds or more and 30 seconds or less.

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