Double container manufacturing method

Abstract

To provide a manufacturing method of a double container capable of forming an outer air introducing hole of a container body with a high precision.SOLUTION: A manufacturing method of a double container having a container body includes a molding step and an outer air introducing hole forming step. In the molding step, a container molded body which becomes the container body is formed, the container molded body including an inner bag and an outer shell disposed to cover the inner bag. In the outer air introducing hole forming step, an outer air introducing hole is formed in the outer shell by locally cutting the outer shell using a cutter in a protruded part provided in the container molded body, the hole allowing outer air to enter a space between the outer shell and the inner bag. The outer air introducing hole forming step is provided with slipping restriction means that prevents the cutter from slipping toward a peak of the protruded part when the cutter comes into contact with the protruded part, and / or is performed in a state in which a step indicating a cutting position of the protruded part is disposed in the protruded part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a double container. [Background technology]

[0002] Patent Document 1 discloses a technique for forming an outside air introduction hole in an outer shell by locally cutting the outer shell with a cutter at a convex portion provided on a container molded body that becomes the container main body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] China Patent Application Publication No. 110480984 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, when the cutter comes into contact with the convex portion, the cutter slides toward the top of the convex portion, and the outside air introduction hole may not be formed accurately. Also, there are cases where it is desired to cut the outer shell at a position other than the base of the convex portion, but in such cases, it may be difficult to determine the cutting position, and therefore the outside air introduction hole may not be formed accurately.

[0005] The present invention has been made in view of the above circumstances, and provides a method for manufacturing a double container that is capable of forming an outside air introduction hole in the container body with high accuracy. [Means for solving the problem]

[0006] According to the present invention, there is provided a method for manufacturing a double container having a container body, the method comprising a molding step and an outside air introduction hole forming step, in which a container molded body which becomes the container body is formed, the container molded body comprising an inner bag and an outer shell arranged to cover the inner bag, and in the outside air introduction hole forming step, an outside air introduction hole which enables outside air to be introduced into the space between the outer shell and the inner bag is formed in the outer shell by locally cutting the outer shell using a cutter at a convex portion provided on the container molded body, and the outside air introduction hole forming step is performed in a state in which a slippage suppression means is provided which suppresses the cutter from sliding toward the top of the convex portion when the cutter abuts the convex portion, and / or a step indicating the cutting position of the convex portion is provided on the convex portion.

[0007] The method of the present invention is performed in a state where anti-slip means is provided and / or a step indicating the cutting position of the convex portion is provided in the convex portion, so that the cutter does not slip or the cutting position is not mistaken, and the outside air introduction hole in the container body can be formed with high accuracy.

[0008] Various embodiments of the present invention will be described below. The embodiments described below can be combined with each other. Preferably, in the method described above, the outside air introduction hole forming process is carried out with the anti-slip means provided, and the anti-slip means includes a protruding portion where the convex portion protrudes toward the cutter side. Preferably, in the above-described method, the outside air introduction hole forming step is performed in a state in which the slippage prevention means is provided, and the slippage prevention means includes a guide provided on the cutter. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a double container 1 according to a first embodiment of the present invention, as viewed from a bottom 2c side. [Diagram 2] FIG. 2A is a bottom view of the double container 1 of FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. 2A. [Diagram 3]3A is a cross-sectional view taken along line AA in FIG. 2B, and FIG. 3B is a cross-sectional view taken along line BB in FIG. 2B. [Figure 4] FIG. 2 is an exploded perspective view of region A in FIG. [Diagram 5] FIG. 5A is a view corresponding to FIG. 2B for the first embodiment of the present invention, FIG. 5B is an enlarged view of region B in FIG. 5A, and FIG. 5C shows the state after removing outer shell 12 at convex portion 22a from the state of FIG. 5A. [Figure 6] 6A to 6C are views corresponding to FIGS. 5A to 5C and relating to a second embodiment of the present invention. [Figure 7] FIG. 7 is a view corresponding to FIG. 6A for a third embodiment of the present invention. [Figure 8] 8A and 8B are views corresponding to FIGS. 5A and 5B, showing a fourth embodiment of the present invention. [Figure 9] FIG. 9 is a view corresponding to FIG. 2B for the fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described. Various features shown in the following embodiments can be combined with each other. Also, each feature can be an invention independently.

[0011] 1. First embodiment 1-1. Structure of double container 1 First, a double container 1 that can be manufactured by the manufacturing method of the double container 1 of the present invention will be described with reference to Figures 1 to 4. The double container 1 comprises a container body 2 and a valve member 3. The double container 1 may be a squeeze type container that expels the contents by compressing the container body 2, or a pump type container that sucks out the contents by the action of a pump.

[0012] As shown in Fig. 1, the container body 2 has a mouth 2a, a body 2b, and a bottom 2c. The mouth 2a is a tubular (preferably cylindrical) portion with an open end. The mouth 2a has an engagement portion to which a mouth attachment member such as a cap or a pump can be attached. The mouth attachment member has a check valve (not shown) and is configured to allow the contents to be discharged but to prevent outside air from flowing into the container body 2.

[0013] The body 2b is disposed adjacent to the mouth 2a on the side farther from the open end than the mouth 2a. The body 2b has a larger outer diameter (in this specification, "outer diameter" means the circumscribed circle diameter when the cross section is not circular) than the mouth 2a. The body 2b is cylindrical, and the bottom 2c is provided at the lower end of the body 2b and closes the lower end of the body 2b.

[0014] 2B, the container body 2 includes an inner bag 14 and an outer shell 12 arranged to cover the inner bag 14. The inner bag 14 shrinks as the contents inside the inner bag 14 decrease. The outer shell 12 is provided with an outside air introduction hole 15 that allows outside air to be introduced into the space between the outer shell 12 and the inner bag 14.

[0015] The outer shell 12 is made of, for example, low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymer, or other polyolefin. The inner bag 14 is preferably made of a plurality of layers. For example, an EVOH layer made of an ethylene-vinyl alcohol copolymer (EVOH) resin can be used as the layer in contact with the outer shell 12, and an inner layer made of, for example, the above-mentioned polyolefin can be used as the layer in contact with the contents. An adhesive layer is preferably provided between the EVOH layer and the inner layer.

[0016] The container body 2 can be formed by biaxial stretch blow molding or direct blow molding. When the container body 2 is formed by direct blow molding, a seal portion 27 is provided on the bottom 2c of the container body 2, which is formed by crushing a cylindrical parison with a pair of split dies and fusing the opposing surfaces of the parison together. The seal portion 27 preferably protrudes from the bottom surface to increase the seal strength, but does not have to protrude.

[0017] The valve member 3 is configured to be capable of controlling the flow of air through the outside air introduction hole 15. As shown in Fig. 3B, a displacement prevention protrusion 3c provided on the valve member 3 is engaged with the container body 2. The displacement prevention protrusion 3c is a protrusion that prevents the valve member 3 from moving along the insertion direction. By engaging the displacement prevention protrusion 3c with the container body 2, the valve member 3 is prevented from being displaced.

[0018] As shown in Fig. 4, the bottom 2c of the container body 2 is provided with a central recessed region 2c1 and a peripheral region 2c2 provided around the central recessed region 2c1. The peripheral region 2c2 forms the ground contact surface of the container body 2. The peripheral region 2c2 is provided with a valve member accommodating recess 7. The outside air introduction hole 15 is disposed within the valve member accommodating recess 7. The valve member 3 is accommodated within the valve member accommodating recess 7. In this state, as shown in Fig. 3A, the outer surface of the valve member 3 is flush with the peripheral region 2c2, and the outer surface of the valve member 3 forms part of the ground contact surface of the container body 2.

[0019] As shown in Figs. 3B and 4, the valve member accommodating recess 7 opens toward the side surface 2d of the container body 2, and the valve member 3 can be inserted into the valve member accommodating recess 7 from the side surface 2d.

[0020] A more specific configuration is as follows. As shown in FIG. 3A, the valve member accommodating recess 7 has a wide portion 7a and a narrow portion 7b. The narrow portion 7b is narrower than the wide portion 7a. The wide portion 7a and the narrow portion 7b are connected, and the narrow portion 7b is disposed closer to the outer surface side of the bottom portion 2c of the container body 2 than the wide portion 7a. The valve member 3 has a wide portion 3a and a narrow portion 3b. The narrow portion 3b is narrower than the wide portion 3a. The wide portion 3a and the narrow portion 3b are connected. The wide portion 3a can be accommodated within the wide portion 7a, and preferably has a complementary shape to the wide portion 7a. The narrow portion 3b can be accommodated within the narrow portion 7b, and preferably has a complementary shape to the narrow portion 7b. Because the width of the wide portion 3a is greater than the width of the narrow portion 7b, the valve member 3 cannot be inserted into the valve member accommodating recess 7 from the bottom 2c side. On the other hand, the wide portion 3a and the narrow portion 3b can be inserted into the wide portion 7a and the narrow portion 7b from the side surface 2d side.

[0021] The direction in which the valve member 3 is inserted from the side surface 2d is preferably a direction (left-right direction in FIG. 2A) perpendicular to the longitudinal direction of the seal portion 27. In other words, this direction is the opening and closing direction of the split mold during blow molding, and the valve member accommodating recess 7 extending in this direction can be easily formed with high accuracy.

[0022] The valve member 3 includes a housing 4 and a core 5. As shown in FIG. 2B and FIG. 4, the housing 4 includes an outer opening 4a, a container side opening 4b, and a core insertion opening 4c. These openings communicate with each other inside the housing 4. The outer opening 4a opens to the outside and faces the central recessed area 2c1. The container side opening 4b opens to the outside air introduction hole 15 side. The core insertion opening 4c opens to the side surface 2d side. As shown in FIG. 3A, the outer opening 4a is disposed in the narrow width portion 3b, and as shown in FIG. 4 and FIG. 5, the container side opening 4b and the core insertion opening 4c are disposed in the wide width portion 3a. The outside air introduction hole 15 is formed on a protrusion 7d provided in the valve member accommodating recess 7, and as shown in FIG. 2B, the protrusion 7d is accommodated in the container side opening 4b.

[0023] The core 5 can be inserted into the housing 4 through the core insertion opening 4c. As shown in FIG. 2B, the core 5 is configured to be able to open and close the flow path 4d between the outer opening 4a and the container side opening 4b. Specifically, the core 5 includes a base 5a and a flap 5b extending from the base 5a. A hinge 5c is provided between the base 5a and the flap 5b. The base 5a is provided closer to the core insertion opening 4c than the flap 5b, and the base 5a closes the core insertion opening 4c. The core 5 is made of an elastic member such as rubber, and the flap 5b is configured to be rotatable with the base 5a as a fulcrum, and the flow path 4d is opened and closed by the flap 5b rotating. The hinge 5c is for making it easier for the flap 5b to rotate, and can be omitted if not required. In addition, the core 5 may be any member that displaces within the housing 4 to open and close the flow path 4d, and may be, for example, a ball of a ball valve.

[0024] When the outer shell 12 is compressed when discharging the contents in the double container 1, the air in the intermediate space between the outer shell 12 and the inner bag 14 presses the flap 5b against the flow path 4d, closing the flow path 4d. In this state, air does not flow out through the outside air introduction hole 15, so the pressure applied to the outer shell 12 is transmitted to the inner bag 14, discharging the contents. When the force applied to the outer shell 12 is removed after discharging the contents, the restoring force of the outer shell 12 reduces the pressure in the intermediate space between the outer shell 12 and the inner bag 14, opening the flap 5b and allowing air from the outer opening 4a to flow into the intermediate space through the outside air introduction hole 15. This allows the outer shell 12 to quickly return to its original shape.

[0025] As shown in Fig. 3B, the displacement prevention protrusions 3c are provided so as to protrude from both side surfaces of the wide portion 3a. Both side surfaces of the wide portion 7a are provided with protrusion accommodating recesses 7c for accommodating the displacement prevention protrusions 3c. The displacement prevention protrusions 3c engage with the protrusion accommodating recesses 7c, thereby preventing displacement of the valve member 3 relative to the container body 2. The displacement prevention protrusions 3c are provided with an inclined surface that becomes lower toward the tip 3d of the valve member 3, which prevents the displacement prevention protrusions 3c from abutting against the edges of the wide portion 7a and impeding insertion.

[0026] The misalignment prevention projection 3c is provided at a position farther from the tip 3d of the valve member 3 than the container-side opening 4b is. The closer the misalignment prevention projection 3c is provided to the tip 3d, the longer the distance over which strong frictional resistance is applied when the valve member 3 is inserted, and the greater the load when the valve member 3 is inserted.

[0027] The displacement prevention projection 3c can be disposed at any position that can prevent displacement of the valve member 3. For example, it may be provided at the narrow width portion 3b or at the bottom surface 3e (the surface where the container side opening 4b is provided) of the valve member 3. Furthermore, when the displacement prevention projection 3c is provided at the bottom surface 3e of the valve member 3, the displacement prevention projection 3c may be engaged with the outside air introduction hole 15.

[0028] 1-2. Structure of double container 1 A method for manufacturing the double container 1 of the first embodiment of the present invention will be described with reference to Fig. 5. This method includes a molding step and an outside air introduction hole forming step. Each step will be described below.

[0029] (1) Molding process 5A, in the molding step, a container molded body 22 is formed to become the container body 2. Like the container body 2, the container molded body 22 includes an inner bag 14 and an outer shell 12 disposed to cover the inner bag 14.

[0030] The container molded body 22 can be formed by direct blow molding or biaxial stretch blow molding. The container molded body 22 has a portion having the same shape as the container body 2, and the container body 2 is formed by forming an outside air introduction hole 15 in the container molded body 22, removing burrs if there are any, and removing the bag part if the mouth part is closed by a bag part. In direct blow molding, the container molded body 22 can be formed by sandwiching a molten cylindrical laminated parison extruded from an extruder between a pair of split dies and blowing air into the parison. In biaxial stretch blow molding, the container molded body 22 can be formed by biaxial stretch blow molding by heating a preform formed by covering an outer preform with an inner preform.

[0031] (2) Air intake hole forming process In the outside air inlet hole forming process, outer shell 12 is locally cut using cutter 25 at protrusion 22a provided on container molding 22, thereby forming outside air inlet hole 15 in outer shell 12 that allows outside air to be introduced into the space between outer shell 12 and inner bag 14, thereby obtaining the structure shown in Figure 5C.

[0032] The localized excision of the outer shell 12 can be performed by sliding the cutter 25. This forms the outside air introduction hole 15. The cutter 25 can be slid in the left-right direction of FIG. 5A. A plane P formed by the outer edge of the outside air introduction hole 15 coincides with a plane formed by the trajectory of the sliding movement of the cutter 25. In other words, the localized excision of the outer shell 12 can be performed by scraping off the outer shell 12, rather than hollowing out the outer shell 12 into a cylindrical shape.

[0033] When the outer shell 12 is removed by such a method, there is a risk that the cutter 25 will slide (move relatively) toward the apex 22c of the convex portion 22a when the cutter 25 abuts against the convex portion 22a. When the cutter 25 slides, the height position of the cutter 25 may change, or the convex portion 22a may be pressed and depressed by the cutter 25, resulting in a change in the height position of the apex 22c, or both of these may occur. In other words, as a result of at least one of the cutter 25 and the apex 22c being displaced, the relative height positions of the cutter 25 and the apex 22c change, and the cutter 25 slides toward the apex 22c of the convex portion 22a. If the cutter 25 slides, the outside air introduction hole 15 cannot be formed with high accuracy. Therefore, in this embodiment, the protruding portion 22d is provided on the convex portion 22a as a slippage suppression means for suppressing the cutter 25 from sliding toward the apex of the convex portion 22a. The protruding portion 22d is a portion where the convex portion 22a protrudes (overhangs) toward the cutter 25, and when the cutter 25 is moved so that the tip of the cutter 25 enters the base side of the protruding portion 22d, the protruding portion 22d prevents the cutter 25 from sliding toward the top portion 22c. The protruding portion 22d may be formed by providing a groove in the convex portion 22a, or may be formed by providing a protrusion that protrudes from the convex portion 22a toward the cutter 25 side.

[0034] In this embodiment, the protrusion 22a has a step 22b, and the base of the step 22b coincides with the base of the protruding portion 22d. In this embodiment, the protrusion 22a is cut off at the base of the step 22b, so that a gap is present between the cutter 25 and the container molded body 22 in areas other than the protrusion 22a. This prevents the cutter 25 from damaging the container molded body 22.

[0035] 2. Second embodiment A second embodiment of the present invention will be described with reference to Fig. 6. This embodiment is similar to the first embodiment, and the following description will focus on the differences.

[0036] In the first embodiment, the top 22c of the protrusion 22a is flat, but in this embodiment, the protrusion 22a is curved so that the top 22c is convex upward. Also, in the first embodiment, the protrusion 22a has a step 22b, but in this embodiment, the protrusion 22a does not have a step 22b.

[0037] In this embodiment, too, protrusion 22d is provided on convex portion 22a, and when cutter 25 is moved so that the tip of cutter 25 enters the base side of protrusion 22d, protrusion 22d prevents cutter 25 from sliding toward top 22c.

[0038] 3. Third embodiment A third embodiment of the present invention will be described with reference to Fig. 7. This embodiment is similar to the second embodiment, and the following description will focus on the differences.

[0039] In this embodiment, the protruding portion 22d is not provided on the convex portion 22a, and instead, the cutter 25 is provided with a guide 26 as a slippage suppression means for suppressing the cutter 25 from sliding toward the top of the convex portion 22a. The guide 26 is disposed so as to abut against the upper surface of the cutter 25, and the cutter 25 slides while being guided by the guide 26. With this configuration, the upward movement of the cutter 25 is prevented by the guide 26, so that the cutter 25 is suppressed from sliding toward the top of the convex portion 22a. It is also possible to use the protruding portion 22d and the guide 26 together.

[0040] 4. Fourth embodiment A fourth embodiment of the present invention will be described with reference to Fig. 8. This embodiment is similar to the first embodiment, and the following description will focus on the differences.

[0041] In this embodiment, the protruding portion 22a has a step 22b similar to the first embodiment, but the protruding portion 22d is not provided on the protruding portion 22a.

[0042] In this embodiment, it is assumed that the convex portion 22a is cut off at a height position between the top 22c of the convex portion 22a and the base 22e of the convex portion 22a. However, if the convex portion 22a does not have a step 22b, it is difficult to know at what height the convex portion 22a should be cut off. On the other hand, in this embodiment, the step 22b is provided in the convex portion 22a, and the step 22b serves as a marker indicating the cutting position of the convex portion 22a. For example, the convex portion 22a can be cut off at the base of the step 22b. Therefore, according to this embodiment, the convex portion 22a can be cut off at an accurate position, and the accuracy of the process of forming the outside air introduction hole 15 can be improved.

[0043] 5. Fifth embodiment A fifth embodiment of the present invention will be described with reference to Fig. 9. This embodiment is similar to the first embodiment, and the following description will focus on the differences.

[0044] In the first embodiment, the inner bag 14 is in close contact with the outer shell 12 near the outside air introduction hole 15, and there is a problem that the inner bag 14 is difficult to peel off from the outer shell 12. To solve this problem, in this embodiment, the valve member 3 is configured to include a main body portion 3f and an insertion portion 3g that protrudes from the main body portion 3f toward the outside air introduction hole 15. The insertion portion 3g is inserted into the outside air introduction hole 15. When the insertion portion 3g is inserted into the outside air introduction hole 15, the inner bag 14 can be pressed to peel off the inner bag 14 from the outer shell 12 near the outside air introduction hole 15. This makes it easier for the inner bag 14 to be peeled off from the outer shell 12, and improves the introduction of outside air into the space between the outer shell 12 and the inner bag 14.

[0045] 6. Other embodiments In the above embodiment, the outside air introduction hole 15 is provided in the valve member accommodating recess 7, but it may be provided in another position. For example, the outside air introduction hole 15 may be provided in the body portion 2b. In the above embodiment, the double container 1 is provided with the valve member 3, but the valve member 3 may be configured differently from that in the above embodiment, or may be omitted. When the valve member 3 is omitted, the "valve member accommodating recess 7" may be simply referred to as a "recess." [Explanation of symbols]

[0046] 1:Double container 2: Container body 2a: Mouth 2b: Torso 2c: Bottom 2c1: Central concave area 2c2: Periphery area 2d: side 3: Valve member 3a: Wide section 3b: Narrow part 3c: Protrusion to prevent misalignment 3d: tip 3e: Bottom 3f: Main body 3g :Insertion part 4: Housing 4a:Outside opening 4b: Container side opening 4c: Core insertion opening 4d: Flow path 5: Core 5a: Bass 5b: Flap 5c: Hinge 7: Valve member receiving recess 7a: Wide section 7b: Narrow part 7c: Protrusion receiving recess 7d: Protrusion 12: Outer shell 14: Inner bag 15: Outside air intake 22: Container molded body 22a: Convex part 22b: Step 22c:Top 22d: Protruding part 22e: Root 25: Cutter 26: Guide 27: Seal part P: face

Claims

1. A method for manufacturing a double container having a container body, comprising the steps of: The method includes a molding step and an outside air introduction hole forming step, In the molding step, a container molded body that becomes the container body is formed, The container molded body includes an inner bag and an outer shell arranged to cover the inner bag, In the outside air introduction hole forming step, the outer shell is locally cut using a cutter at a convex portion provided on the container molded body to form an outside air introduction hole in the outer shell that allows outside air to be introduced into a space between the outer shell and the inner bag; The outside air introduction hole forming step is performed in a state where a step indicating a cutting position of the protrusion is provided in the protrusion.

2. A method for manufacturing a double container having a container body, comprising: The method includes a molding step and an outside air introduction hole forming step, In the molding step, a container molded body that becomes the container body is formed, The container molded body includes an inner bag and an outer shell arranged to cover the inner bag, In the outside air introduction hole forming step, the outer shell is locally cut using a cutter at a convex portion provided on the container molded body to form an outside air introduction hole in the outer shell that allows outside air to be introduced into a space between the outer shell and the inner bag; the outside air introduction hole forming step is performed in a state in which a slippage suppression means is provided to suppress the cutter from slipping toward the top of the protrusion when the cutter abuts against the protrusion, The slippage suppression means includes a protruding portion where the convex portion protrudes toward the cutter.

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