Storage container and method of manufacturing the same

Abstract

The present invention provides a storage container with excellent appearance. According to the present invention, a storage container is provided, which has a container body integrally formed with an outer shell in a manner of covering the outer peripheral surface of an inner container, the outer shell is injection molded, the inner container has an outermost layer and an adjacent layer adjacent to the outermost layer, and the melting point of the outermost layer resin constituting the outermost layer is lower than the melting point of the adjacent layer resin constituting the adjacent layer.

Description

Technical Field

[0001] The present invention relates to a storage container capable of storing contents and a manufacturing method thereof, as well as a double-layer container and a manufacturing method thereof. Background Art

[0002] (First point of view)

[0003] There is currently known a laminated peelable container that reduces shrinkage of an inner bag along with the content and suppresses entry of air into the container (for example, Patent Document 1).

[0004] (Second point of view)

[0005] There is known a double-layer container (laminated peelable container) having an outer shell and an inner bag and capable of accommodating contents in the inner bag (e.g., Patent Document 2). The outer shell can be pressed from the outside, and the contents accommodated in the inner bag flow out from the mouth by the pressing. After the pressing, air is introduced between the outer shell and the inner bag through a check valve provided in the outer shell, thereby restoring the shape of the outer shell and gradually shrinking the inner bag.

[0006] (Third point of view)

[0007] Patent Document 3 discloses a method for manufacturing a double-layer container by blow molding in a state where an inner preform and an outer preform overlap.

[0008] Prior art documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2015-163531

[0011] Patent Document 2: Japanese Patent Application Publication No. 2018-087036

[0012] Patent document 3: WO2004 / 071887 Summary of the invention

[0013] (Problems to be solved by the invention)

[0014] (First point of view)

[0015] The laminated peelable container of Patent Document 1 is formed by blow molding with the outer peripheral surface of the container covered with a shrink film, but a design that can give a more luxurious appearance is sometimes required.

[0016] The present invention has been made in view of the above circumstances, and provides a storage container having an excellent appearance.

[0017] (Second point of view)

[0018] However, in the prior art described in Patent Document 2, since the air introduction hole for inserting the check valve is located near the mouth, air needs to be introduced from the bottom to the top of the container immediately after the contents are taken out, which is inefficient.

[0019] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a double-layer container in which an inner bag can be more effectively peeled off from an outer bag after taking out the contents.

[0020] (Third point of view)

[0021] The inner bag is formed by the inner preform, and the outer bag is formed by the outer preform. As the content in the inner bag decreases, the inner bag shrinks, but the outer bag can maintain its original state by introducing external air into the intermediate space between the inner bag and the outer bag through the external air introduction hole set in the outer bag.

[0022] In this double-layer container, the inventors of the present invention have found that it is sometimes difficult to introduce external air into the intermediate space between the inner bag and the outer shell when the external air introduction hole is provided at the bottom of the container for the sake of aesthetics.

[0023] The present invention is made in view of the above situation, and provides a double-layer container that can smoothly introduce external air into the intermediate space between the inner bag and the outer shell even if an external air introduction hole is provided at the bottom of the container body.

[0024] (Technical solutions to solve problems)

[0025] (First point of view)

[0026] According to the present invention, a storage container is provided, which has a container body integrally formed with an outer sleeve in a manner of covering the outer peripheral surface of the inner container, the outer sleeve is an injection molded body, the inner container has an outermost layer and an adjacent layer adjacent to the outermost layer, and the melting point of the outermost layer resin constituting the outermost layer is lower than the melting point of the adjacent layer resin constituting the adjacent layer.

[0027] The storage container of the present invention has an excellent appearance because the outer jacket composed of the injection molded body is integrally formed with the outer peripheral surface of the inner container. In addition, since the melting point of the outermost layer resin is lower than the melting point of the adjacent layer resin, the heat energy of the molten resin used for injection molding the outer jacket is not easily transmitted to the inner container, thereby suppressing the deformation of the inner container. In addition, since the melting point of the outermost layer resin is lower than the melting point of the adjacent layer resin, the adhesion between the outer jacket and the outermost layer is improved, thereby suppressing the peeling of the outer peripheral surface of the inner container and the adhesive surface of the outer jacket caused by the impact of falling or the like.

[0028] Various embodiments of the present invention are listed below. The embodiments described below can be combined with each other.

[0029] It is preferable that the difference between the melting point of the outermost layer resin of the storage container and the melting point of the adjacent layer resin is 5° C. or more.

[0030] It is preferred that the wall thickness of the outermost layer is 10% or more relative to the wall thickness of the inner container of the storage container.

[0031] It is preferred that the outermost layer resin of the storage container contains unmodified polyolefin.

[0032] It is preferred that the outermost layer resin of the storage container contains an acid-modified polyolefin and the unmodified polyolefin.

[0033] It is preferable that the resin constituting the outer jacket of the storage container has the same monomer units as the outermost layer resin.

[0034] It is preferred that the inner container of the storage container has an outer shell and an inner bag, and the inner bag shrinks as the content decreases, and the outermost layer and the adjacent layer are provided on the outer shell.

[0035] The manufacturing method of the storage container preferably comprises an integral molding step of integrally molding an inner container and an outer shell, in which, with the outer peripheral surface of the inner container arranged in a mold, a resin is filled into the space outside the inner container in the cavity of the mold to form the outer shell, the inner container comprises an outermost layer and an adjacent layer adjacent to the outermost layer, and the melting point of the outermost layer resin constituting the outermost layer is lower than the melting point of the adjacent layer resin constituting the adjacent layer.

[0036] Preferably, in the method, pressurizing the interior of the inner container during the integral molding step.

[0037] Preferably, in the integral molding step of the method, the resin is filled in a state where the inner surface of the bottom surface of the inner container is pressed using a support rod inserted into the inner container.

[0038] (Second point of view)

[0039] According to one embodiment of the present invention, a double-layer container is provided, comprising an outer shell, an external air inlet hole, and an inner bag, wherein the outer shell is configured to be pressurizable from the outside, and the pressing causes the contents contained in the inner bag to flow out from the mouth, and the external air inlet hole is arranged in a specific area on the bottom side of the outer shell, and the bottom side refers to the side away from the mouth when the double-layer container is divided into two equal parts in the height direction, and is configured to be engaged with a check valve, through which, after the contents flow out, air is introduced into the intermediate space between the inner side of the outer shell and the outer side of the inner bag to restore the shape of the outer shell, and the inner bag is configured so that when the contents are reduced, the air introduced into the intermediate space is pressed and contracted.

[0040] Since the specific area provided with the air introduction hole is arranged on the bottom side of the outer shell, the double-layer container has an advantageous effect that the inner bag can be effectively peeled off from the outer shell immediately after the contents are taken out.

[0041] (Third point of view)

[0042] According to the present invention, a double-layer container is provided, which comprises a container body which is constructed with an outer shell and an inner bag and the inner bag shrinks as the content decreases, the container body comprises a cylindrical body and a bottom arranged at the lower end of the body, the bottom comprises a central recessed portion arranged at the center of the bottom and a peripheral portion surrounding the central recessed portion, in the central recessed portion, an external air inlet hole is arranged in the outer shell, and a spacer component for forming a gap between the outer shell and the inner bag is arranged in the peripheral portion.

[0043] The present invention has been studied in detail and found that when a central recess is provided at the bottom of the container body, it is difficult to form a gap between the inner bag and the outer shell at the peripheral portion surrounding the central recess, and therefore, when an external air introduction hole is provided at the central recess, it is not easy to introduce external air into the body of the container body. In addition, based on this finding, by providing a spacing member for forming a gap between the outer shell and the inner bag, external air can be smoothly introduced from the external air introduction hole at the bottom through the peripheral portion into the body, thereby completing the present invention.

[0044] Various embodiments of the present invention are listed below. The embodiments shown below can be combined with each other.

[0045] It is preferred that the partition member of the double-layer container is a protrusion provided on the outer bag or the inner bag.

[0046] It is preferred that the partition members of the double container are arranged radially.

[0047] It is preferred that the spacing members of the double-layer container are arranged to form a discontinuous circle.

[0048] Preferably, the container body of the double container is blow-molded by heating the inner preform and the outer preform in a state where an outer preform constituting the outer shell is covered on an inner preform constituting the inner bag.

[0049] Preferably, the inner preform of the double-layer container has a positioning pin at the bottom of the inner preform, and the outer preform has a positioning hole at the bottom of the outer preform, and the blow molding is performed with the positioning pin inserted into the positioning hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a perspective view of the storage container 101 according to the first embodiment of the first viewpoint.

[0051] Figure 2 It is a perspective view of the container body 102 .

[0052] Figure 3 It is a cross-sectional view of the container body 102 .

[0053] Figure 4 yes Figure 3 The layer structure of the container body 102 in the area A in FIG.

[0054] Figure 5 It is a perspective view of the inner container 104 .

[0055] Figure 6 is a cross-sectional view of the inner container 104 .

[0056] Figure 7 This is a cross-sectional view for explaining the integral molding process.

[0057] Figure 8 yes Figure 7 Magnified view of area B in FIG.

[0058] Fig. 9 middle, Fig. 9 A~ Fig. 9 B is a perspective view of the storage container 101 according to the second embodiment when viewed from a different direction.

[0059] Fig.10 yes Fig. 9 A is a cross-sectional view of the container body 102.

[0060] Fig.11 yes Fig.10 The layer structure of the container body 102 in the area C in FIG.

[0061] Fig.12 It only shows Fig.10 A cross-sectional view of the inner container 104 in FIG.

[0062] Fig.13 is a perspective view of the pump 112 .

[0063] Fig.14 This shows a state in which the external air introduction part 115 is provided at the mouth 108 of the inner container 104 in the third embodiment. Figure 5 An enlarged view of the vicinity of the mouth 108.

[0064] Fig.15 It is a perspective view of the double container 1 according to the first embodiment showing the second viewpoint.

[0065] Fig.16 It means from Fig.15 The state is the state after the cover 30 is removed.

[0066] Fig.17 Shown are a front view and a back view of the double container 1 according to the first embodiment of the second aspect.

[0067] Fig.18 It means from Fig.17 The state after the cover 30 is removed.

[0068] Fig.19 Shown are a left side view and a right side view of the double container 1 according to the first embodiment of the second viewpoint.

[0069] Fig. 20 It means from Fig.19 The state is the state after the cover 30 is removed.

[0070] Fig.21 Shown are a top view and a bottom view of the double container 1 according to the first embodiment of the second aspect.

[0071] Fig. 22 It means from Fig.21 Status: Status after cover 30 is removed.

[0072] Fig.23 It is an end view showing the internal structure of the double container 1 according to the first embodiment of the second viewpoint.

[0073] Fig.24 The detailed structure of the check valve 6 is shown.

[0074] Fig.25 FIG. 1 is a perspective view of a double container 1 according to a second embodiment of the second viewpoint.

[0075] Fig.26 It means from Fig.25 The state is the state after the cover 30 is removed.

[0076] Fig. 27 Shown are a front view and a back view of a double container 1 according to a second embodiment of the second viewpoint.

[0077] Fig.28 It means from Fig. 27 The state is the state after the cover 30 is removed.

[0078] Fig.29 Shown are a left side view and a right side view of a double container 1 according to a second embodiment of the second viewpoint.

[0079] Fig.30 It means from Fig.29 The state is the state after the cover 30 is removed.

[0080] Fig.31Shown are a top view and a bottom view of a double container 1 according to a second embodiment of the second viewpoint.

[0081] Fig.32 It means from Fig.31 The state is the state after the cover 30 is removed.

[0082] Fig.33 This is an end view showing the internal structure of a double container 1 according to a second embodiment of the second viewpoint.

[0083] Fig.34 The container body 202 of the double container 201 according to the first embodiment of the third aspect of the present invention is shown. Fig.34 A is the front view. Fig.34 B is the bottom view.

[0084] Fig.35 middle, Fig.35 A is from the bottom 207 Fig.34 A perspective view of the container body 202, Fig.35 B is a cross-sectional perspective view of the vicinity of the bottom 207 of the outer shell 203 as viewed from the inside of the container.

[0085] Fig.36 middle, Fig.36 A is Fig.34 Section A-A in B, Fig.36 B is Fig.36 Section B-B in A.

[0086] Fig.37 The figure shows a perspective view of the inner preform 214 and the outer preform 213 in a separated state.

[0087] Fig.38 It is viewed from the inside of the outer preform 213. Fig.37 A cross-sectional perspective view of the outer preform 213 near the bottom 213c.

[0088] Fig.39 middle, Fig.39 A is a perspective view of an assembly 215 formed by covering an outer preform 213 on an inner preform 214, Fig.39 B is from other perspectives Fig.39 A stereogram.

[0089] Fig.40 The figure shows a biaxial stretch blow molding process, and is a cross-sectional view of a state where the assembly 215 is mounted on the mouth support mold 221 .

[0090] Fig.41 It means from Fig.40This is a cross-sectional view of a state in which the forming dies 223 and 224 are closed and the bottom supporting die 222 supports the bottom 213 c of the outer preform 213 .

[0091] Fig.42 is from Fig.41 The cross-sectional view is a state in which the support rod 225 is extended and the bottom support mold 222 is simultaneously moved backward to extend the assembly 215 longitudinally.

[0092] Fig.43 The outer preform 213 is shown with a non-continuous circular protrusion 213c1, which is Fig.38 Corresponding cross-sectional stereogram.

[0093] Fig.44 The figure shows a perspective view of an inner preform 214 having a structure in which radial protrusions 214c2 are provided on a bottom 214c.

[0094] Fig.45 It is a perspective view showing the inner preform 214 having a structure in which a protrusion 214c2 having a discontinuous circle is provided on the bottom 214c.

[0095] Fig.46 This is an enlarged view of the vicinity of the bottom 214g of the inner preform 214 according to the modified example. DETAILED DESCRIPTION

[0096] The following describes the embodiments of the present invention. The various features shown in the embodiments shown below can be combined with each other. In addition, each feature can independently constitute the present invention.

[0097] (First point of view)

[0098] 1. First embodiment

[0099] like Figure 1 As shown, the storage container 101 according to the first embodiment of the present invention comprises: a container body 102; and a plug opening member 103 such as a cover having a flat upper surface. The plug opening member 103 may be a pump or a hinged cover. Figure 3 As shown in FIG. 1 , the container body 102 includes an inner container 104 and an outer casing 105 integrally formed therewith. Each structure will be described below.

[0100] <Inner container 104>

[0101] like Figure 5-6The inner container 104 shown can be a container formed by any manufacturing method, wherein preferably it is a blow-molded container formed by blow molding a preform. Blow molding can be direct blow molding or injection blow molding. In direct blow molding, a pair of split molds are used to clamp a preform in a molten state extruded from an extruder, and air is blown into the inside of the preform to manufacture a container. The preform can be cylindrical or sheet-shaped. In injection blow molding, a test tube-shaped preform with a bottom called a preform is formed by injection molding, and then the preform is blow molded to manufacture a container.

[0102] Since it is not easy to manufacture a multi-layered injection molded container, it is particularly important to apply the present invention to the multi-layered inner container 104. When forming the multi-layered inner container 104, the parison also has a multi-layered structure. The multi-layered parison (multi-layered parison) can be formed by coextrusion.

[0103] The inner container 104 is a bottomed cylindrical shape and includes a receiving portion 107 for receiving the contents and a mouth portion 108 for discharging the contents from the receiving portion 107. The receiving portion 107 includes a body 107a and a bottom portion 107b. The mouth portion 108 is provided with an engaging portion (external thread portion) 8a so that the plug opening member 103 can be mounted.

[0104] When the inner container 104 is formed by direct blow molding, there is a pinch-off portion 107c (eg, Figure 6 ). The pinch-off portion 107c is provided at the bottom 107b of the inner container 104. At the pinch-off portion 107c, the bottom of the inner container 104 is sealed by welding the opposite surfaces of the parison to each other. The shape of the receiving portion 107 may be various shapes such as a cylinder, a polygonal prism, a polygonal cone, or a sphere.

[0105] like Figure 4 As shown, the inner container 104 includes an outermost layer 104c1, an adjacent layer 104c2, and other layers 104c3 in order from the outside of the inner container 104. Examples of the raw material constituting the inner container 104 include unmodified polyolefins, acid-modified polyolefins, and EVOH. Examples of the polyolefin include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymers, and mixtures thereof.

[0106] The melting point of the outermost layer resin constituting the outermost layer 104c1 is lower than the melting point of the adjacent layer resin constituting the adjacent layer 104c2. Although the heat energy of the molten resin may soften and deform the inner container 104 when the outer cover 105 is injection molded, when the melting point of the outermost layer resin is lower than the melting point of the adjacent layer resin, the outermost layer resin is melted by the heat energy of the molten resin, and at this time, the outermost layer resin absorbs the heat energy, thereby reducing the heat energy transferred to the inner container 104, so that the deformation of the inner container 104 caused by the injection pressure can be suppressed. In addition, since the outermost layer 104c1 is easily melted, the adhesion between the outer cover 105 and the outermost layer 104c1 can be improved, so that the peeling of the bonding surface between the outer peripheral surface of the inner container 104 and the outer cover 105 due to the impact of falling can be suppressed. It should be noted that in this specification, "melting point" refers to the melting peak temperature Tpm measured according to JIS K7121:2012.

[0107] The difference between the melting point of the outermost layer resin and the melting point of the adjacent layer resin is preferably 5°C or more, more preferably 10°C or more, and further preferably 20°C or more. This is because in this case, the effects of suppressing deformation and improving adhesion are significant. The difference in melting point is, for example, 5 to 50°C, specifically, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50°C, and may also be a range between any two values ​​shown here.

[0108] The melting point of the outermost layer resin is, for example, 90 to 130° C., preferably 100 to 120° C. The melting point may be, for example, 90, 95, 100, 105, 110, 115, 120, 125, or 130° C., or may be in the range between any two values ​​shown here.

[0109] The wall thickness of the outermost layer 104c1 is preferably 10% or more, preferably 15% or more, and more preferably 20% or more relative to the wall thickness of the inner container 104. This is because in this case, the effects of suppressing deformation and improving adhesion are significant. The wall thickness of the outermost layer 104c1 is, for example, 10 to 50% relative to the wall thickness of the inner container 104, and specifically can be, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50%, or can be a range between any two values ​​shown here.

[0110] The outermost layer resin preferably contains polyolefin, which may be unmodified polyolefin or modified polyolefin (eg, acid-modified polyolefin).

[0111] The outermost layer resin preferably contains unmodified polyolefin. When the outermost layer resin is composed of only modified polyolefin, the outermost layer 104c1 may become sticky and the operability of the inner container 104 may be deteriorated. As the unmodified polyolefin, polyethylene is preferred, and one or both of LDPE and LLDPE are more preferred. This is because the melting point of the outermost layer resin is likely to be low in this case.

[0112] The outermost layer resin may also contain an acid-modified polyolefin and an unmodified polyolefin. Acid-modified polyolefin has excellent adhesiveness, so by containing an acid-modified polyolefin and an unmodified polyolefin in the outermost layer resin, the adhesiveness of the outer cover 105 and the inner container 104 can be improved while suppressing excessive stickiness. The content of the acid-modified polyolefin in the outermost layer resin is, for example, 5 to 95% by mass, preferably 30 to 70% by mass. The content may be specifically 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95% by mass, or may be a range between any two values ​​shown here.

[0113] The adjacent layer 104c2 is a layer adjacent to the outermost layer 104c1. The adjacent layer resin constituting the adjacent layer 104c2 can be any resin having a higher melting point than the outermost layer resin. For example, when the outermost layer resin is LDPE, HDPE or PP etc. having a higher melting point than LDPE can be used as the adjacent layer resin. In addition, as the adjacent layer resin, a recycled resin obtained by recycling the flash generated in the previous production process and reusing it can also be used. When the melting point of the resin forming any layer constituting the inner container 104 is higher than the outermost layer 104c1, the melting point of the recycled resin will usually be higher than the melting point of the outermost layer resin.

[0114] Relative to the wall thickness of the inner container 104, the wall thickness of the adjacent layer 104c2 is, for example, 5 to 70%, specifically, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70%, or a range between any two values ​​shown here.

[0115] The other layer 104c3 refers to a layer located closer to the inner side of the inner container 104 than the adjacent layer 104c2. The other layer 104c3 is preferably made of a resin having excellent heat resistance and rigidity, and may be made of a polypropylene resin, for example. The other layer 104c3 may be omitted when not needed. The wall thickness of the adjacent layer 104c2 is preferably 20% or more relative to the wall thickness of the inner container 104. In this case, the other layer 104c3 may easily improve the heat resistance or rigidity of the inner container 104. The wall thickness of the adjacent layer 104c2 is, for example, 0 to 70% relative to the wall thickness of the inner container 104, and specifically, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70%, or may be a range between any two values ​​shown here.

[0116] The inner container 104 is a multilayer container of, for example, five types of six layers, and its specific layer structure is as follows: The adhesive layer is a layer made of an adhesive resin such as acid-modified polypropylene.

[0117]

Table 1

[0118]

[0119] As shown in Table 2, the adjacent layer 104c2 may be a recycled resin layer. The recycled resin contains various resins constituting the outermost layer 104c1 and other layers 104c3. Since the melting point of the resin constituting other layers 104c3 is higher than the melting point of the outermost layer resin, the melting point of the recycled resin will also become higher than the melting point of the outermost layer resin.

[0120]

Table 2

[0121]

[0122] <Jacket 105>

[0123] like Figure 2-Figure 3 As shown, the outer sleeve 105 is integrally formed in a manner to cover the outer peripheral surface 104a (preferably the outer peripheral surface 104a and the bottom surface 104b) of the inner container 104, and is an injection molded body. The outer sleeve 105 includes a cylinder 105a and a bottom 105b. The cylinder 105a and the bottom 105b cover the outer peripheral surface 104a and the bottom 104b respectively. The outer sleeve 105 covers at least the receiving portion 107, and may or may not cover the mouth 108.

[0124] The resin constituting the outer jacket 105 preferably has the same monomer units as the outermost layer resin constituting the outermost layer 104c1. In this case, it is possible to suppress the peeling of the adhesive surface between the outer jacket 105 and the outer peripheral surface 104a when dropped. For example, polyethylene can be used for the outermost layer 104c1 of the inner container 104, and an ionomer resin of ethylene-(meth)acrylic acid copolymer can be used for the outer jacket 105. In this case, both resins contain ethylene units.

[0125] The container body 102 can be manufactured by using a method including an integral molding process of integrally molding the inner container 104 and the outer casing 105. Figure 7-8 As shown, in the integral molding process, the mouth portion 108 is fixed to the fixing portion 110 having the opening portion 110a, and the outer peripheral surface 104a (preferably the outer peripheral surface 104a and the bottom surface 104b) of the inner container 104 is arranged in the mold 109 for injection molding, and the support rod 111 is inserted into the inner container 104 and pressed against the inner surface of the bottom surface 104b. In this way, displacement of the receiving portion 107 of the inner container 104 during injection molding can be suppressed.

[0126] In this state, the outer cover 105 is formed by filling the resin into the space outside the inner container 104 in the cavity 109a of the mold 109. At this time, it is preferred to pressurize the inside of the inner container 104 so that the inner container 104 will not be deformed due to the pressure of the resin. Pressurization can be performed by blowing water or air. The resin is filled into the cavity 109a from the gate 109b. The gate 109b is preferably arranged at a position opposite to the bottom surface 104b of the inner container 104 (preferably the pinch-off portion 107c). This is because in this case, it is easy to evenly fill the resin into the entire periphery of the inner container 104.

[0127] The injection molding resin preferably has fluidity required for injection molding at a temperature lower than the melting point of the resin constituting the outermost layer 104c1 of the inner container 104. The melting point of the injection molding resin is, for example, 60 to 100° C., preferably 70 to 90° C. The melting point is specifically, for example, 60, 65, 70, 75, 80, 85, 90, 95, 100° C., and may be in the range between any two of the values ​​shown here.

[0128] The difference between the melting point of the injection molding resin and the melting point of the outermost layer resin is preferably 5° C. or more, more preferably 10° C. or more, and even more preferably 20° C. or more. The difference in melting point is, for example, 5 to 50° C., specifically, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50° C., and may be a range between any two values ​​shown here.

[0129] The resin temperature during injection molding is preferably 180 to 230° C. If the temperature is too low, the pressure during injection will increase, and if the temperature is too high, air will easily mix during injection. The resin temperature is specifically, for example, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230° C., and may also be a range between any two values ​​shown here.

[0130] 2. Second Embodiment

[0131] The second embodiment of the present invention is described below. This embodiment is similar to the first embodiment, and the inner container 104 has the following Figure 11-12 The main difference is the outer shell 113 and the inner bag 114 shown, and the inner bag 114 shrinks as the content decreases, that is, the part that constitutes the laminated peeling container. The following description focuses on this difference.

[0132] In this embodiment, the laminated delamination container separates the inner bag 114 from the outer bag 113 as the content decreases, so that the inner bag 114 separates and shrinks from the outer bag 113. In this container, since outside air is not easy to enter the inner bag 114, deterioration of the content can be suppressed.

[0133] like Fig.11 As shown, the outer shell 113 is composed of, for example, an outermost layer 113c1, an adjacent layer 113c2, and other layers 113c3. The inner bag 114 includes, for example, an outermost layer 114c1, an adhesive layer 114c2, and an inner layer 114c3. The outermost layer 113c1 and the adjacent layer 113c2 correspond to the outermost layer 104c1 and the adjacent layer 104c2 involved in the first embodiment, and their configuration and effects are the same as those of the first embodiment.

[0134] The other layers 113c3, the outermost layer 114c1, the adhesive layer 114c2, and the inner layer 114c3 correspond to the other layers 104c3 of the first embodiment. The other layers 113c3 and the inner layer 114c3 can be composed of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymer, and mixtures thereof. The outermost layer 114c1 is a layer with excellent peelability from the other layers 113c3, and is preferably composed of ethylene-vinyl alcohol copolymer (EVOH) resin. The adhesive layer 114c2 is preferably composed of an adhesive resin such as an acid-modified polyolefin.

[0135] like Fig.12 As shown, the pinch-off portion 107c blocks the bottom of the outer shell 113 and the inner bag 114, respectively. However, since the pinch-off portion 107c on the outer shell 113 is particularly weak, the pinch-off portion 107c can be opened on the outer shell 113 by applying an impact to the outer shell 113 to form an external air introduction portion 115. External air can also be introduced between the outer shell 113 and the inner bag 114 through the external air introduction portion 115. The external air introduction portion 115 can be formed by perforating the outer shell 113. The external air introduction portion 115 can be provided in the receiving portion 107 or in the mouth portion 108.

[0136] When the external air introduction part 115 of the inner container 104 is covered by the outer jacket 105, the external air cannot be introduced through the external air introduction part 115. Therefore, the outer jacket 105 is provided with a vent 105c that communicates the outer space of the storage container 101 with the external air introduction part 115. The vent 105c may be a through hole or a groove. The vent 105c may be formed during injection molding or by post-processing after injection molding.

[0137] When the outer cover 105 does not cover the mouth 108, if the external air introduction portion 115 is provided on the mouth 108, the vent 105c is not necessary.

[0138] When the vent 105 c is formed during injection molding, for example, a method can be adopted in which a needle pin is first arranged at a position corresponding to the vent 105 c and then the needle pin is pulled out from the outer sleeve 105 when the container body 102 is removed from the mold 109 .

[0139] It is preferable that the inner bag 114 is peeled off in advance before the integral molding process of the inner container 104. This is because it is easy to peel off in advance before the outer cover 105 is integrally molded in the inner container 104.

[0140] <Pump 112>

[0141] The pump 112 is configured to discharge the content from the inner container 104. When the inner container 104 is a delamination container, it is preferable that the pump 112 is configured not to introduce external air into the inner container 104.

[0142] like Fig.13 As shown, the pump 112 includes a main body 112a, a piston 112b, a nozzle 112c, and a tube 112d. The main body 112a includes a barrel 112a1, a cylinder 112a2, and an upper wall 112a3. An engaging portion (internal thread portion) (not shown) engaging with the engaging portion (external thread portion) 108a is provided on the inner surface of the barrel 112a1. The cylinder 112a2 is inserted into the mouth 108. The outer diameter of the cylinder 112a2 is substantially consistent with the inner diameter of the mouth 108. The cylinder 112a2 is cylindrical, and the piston 112b is slidable in the cylinder 112a2. The internal space of the cylinder 112a2 is connected to the nozzle 112c and the tube 112d. A valve mechanism consisting of an elastic member and a valve is hidden in the internal space of the cylinder 112a2. The valve mechanism is operated by sliding the piston portion 112b, so that the sucked-up contents can be discharged from the nozzle 112c through the tube 112d.

[0143] 3. Third embodiment

[0144] Reference Fig.14 The third embodiment of the present invention will be described. This embodiment is similar to the second embodiment, and its main distinguishing feature is that the external air introduction portion 115 is provided at the mouth 108 of the inner container 104. The distinguishing feature will be described below.

[0145] When the outer shell 113 is sealed, the outside air introduction part 115 is not provided in the pinch-off part 107c, and it is preferred that a through hole is provided in the outer shell 113 to constitute the outside air introduction part 115. In this case, the outside air introduction part 115 is preferably provided at a position where the inner container 104 is not covered by the outer shell 105. In this case, the vent 105c may not be provided on the outer shell 105.

[0146] like Fig.14 As shown, the external air introduction part 115 is preferably arranged at the mouth 108, and is particularly preferably arranged at the Fig.12The position covered by the barrel 112a1 of the pump 112 shown in the figure. In this case, the external air introduction part 115 is invisible when the pump 112 is installed, so the appearance is beautiful. The external air introduction part 115 can be ventilated to the outside through a gas passage such as the gap between the piston part 112b and the barrel 112a1 or the gap between the lower end of the barrel 112a1 and the inner container 104.

[0147] The external air introduction portion 115 is preferably provided at the flat portion 108b provided at the mouth 108. In this case, the external air introduction portion 115 can be easily formed using a drilling tool such as a drill. The flat portion 108b can be provided at a position closer to the housing portion 107 than the engaging portion 108a, or can be provided to divide the engaging portion 108a. In the latter case, there is an advantage that the mouth 108 does not need to be extended in order to provide the flat portion 108b.

[0148] (Second point of view)

[0149] 1. First embodiment of the second aspect

[0150] In this section, the structure of the double container 1 according to the first embodiment will be described. Fig.15 1 is a perspective view of a double container 1 according to the first embodiment. Fig.16 It means from Fig.15 Status: Status after cover 30 is removed. Fig.17 Shown are a front view and a rear view of a double container 1 according to the first embodiment. Fig.18 It means from Fig.17 State: The state after the cover 30 is removed. Fig.19 Shown are a left side view and a right side view of the double container 1 according to the first embodiment. Fig. 20 It means from Fig.19 State: The state after the cover 30 is removed. Fig.21 Shown are a top view and a bottom view of a double container 1 according to the first embodiment. Fig. 22 It means from Fig.21 State: The state after the cover 30 is removed.

[0151] 1.1 Subject 2

[0152] The double-layer container 1 is a so-called laminated peeling container. Figure 15 to Figure 22 As shown, the double-layer container 1 includes a main body 2 (an outer shell 21 and an inner bag 22) and an external air introduction hole 52. The outer shell 21 can be pressed from the outside. It is configured so that the contents contained in the inner bag 22 (the storage space 26) flow out from the mouth 3 by pressing. The inner bag 22 is configured so that when the contents are reduced, it is compressed by the air introduced into the intermediate space 25 through the external air introduction hole 52.

[0153] The outer shell 21 and the inner bag 22 are blow-molded in a multi-layer parison manner and are formed in an integral state. The inner bag 22 is peeled off from the outer shell 21 before use, and then filled with contents until the inner bag 22 contacts the outer shell 21. The contents are squeezed out and the inner bag 22 shrinks smoothly. Alternatively, the inner bag 22 and the outer shell 21 may be joined, and then the inner bag 22 may be peeled off from the outer shell 21 as the contents are discharged.

[0154] As described above, the main body 2 includes the outer shell 21 and the inner bag 22. The outer shell 21 is thicker than the inner bag 22 to improve shape recovery.

[0155] The outer shell 21 is composed of, for example, low-density polyethylene, linear low-density polyethylene, polyethylene, polypropylene, ethylene-propylene copolymers, and mixtures thereof. The outer shell 21 is a single-layer or multi-layer structure, and preferably contains a lubricant in at least one of the innermost layer and the outermost layer. When the outer shell 21 is a single-layer structure, its single layer is the innermost layer and the outermost layer, and the lubricant can be contained in this layer. When the outer shell 21 is a two-layer structure, the layer on the inner side of the container is the innermost layer, and the layer on the outer side of the container is the outermost layer, and a lubricant can also be contained in at least one of them. When the outer shell 21 is composed of three or more layers, the layer on the innermost side of the container is the innermost layer, and the layer on the outermost side of the container is the outermost layer.

[0156] The innermost layer of the outer shell 21 is a layer in contact with the inner bag 22. By including a lubricant in the innermost layer of the outer shell 21, the peelability between the outer shell 21 and the inner bag 22 can be improved. The outermost layer of the outer shell 21 is a layer in contact with the mold during blow molding. By including a lubricant in the outermost layer of the outer shell 21, the demolding property can be improved.

[0157] One or both of the innermost layer and the outermost layer of the outer shell 21 may be formed of a random copolymer of propylene and other monomers. This can improve the shape recovery, transparency, and heat resistance of the outer shell 21 as an outer shell.

[0158] The random copolymer is a copolymer in which the content of monomers other than propylene is less than 50 mol%, preferably 5 to 35 mol%. As the monomer copolymerized with propylene, any monomer that improves the impact resistance of the random copolymer compared with the homopolymer of polypropylene is sufficient, and ethylene is particularly preferred. When it is a random copolymer of propylene and ethylene, the content of ethylene is preferably 5 to 30 mol%. The weight average molecular weight of the random copolymer is preferably 100,000 to 500,000, more preferably 100,000 to 300,000.

[0159] The tensile modulus of the random copolymer is preferably 400 to 1600 MPa, more preferably 1000 to 1600 MPa. When the tensile modulus of the random copolymer is within this range, the shape recovery property is particularly good.

[0160] When the container is too hard, the feel of the container becomes worse, so the random copolymer can be mixed with a soft material such as linear low-density polyethylene to form the outer shell 21. However, it is preferred that the material mixed with the random copolymer is less than 50% by weight relative to the entire mixture so as not to significantly impair the effective performance of the random copolymer. For example, the random copolymer and the linear low-density polyethylene can be mixed in a weight ratio of 85:15 to form the outer shell 21.

[0161] The inner bag 22 includes an EVOH layer disposed on the outer surface of the container, an inner layer disposed on the inner surface of the EVOH layer, and an adhesive layer disposed between the EVOH layer and the inner layer. The EVOH layer can improve gas barrier properties and peelability from the outer shell 21.

[0162] The EVOH layer is a layer composed of ethylene-vinyl alcohol copolymer (EVOH) resin, which can be obtained by hydrolyzing ethylene and ethyl acetate copolymer. The ethylene content of the EVOH resin is, for example, 25 to 50 mol%, preferably 32 mol% or less from the perspective of oxygen barrier properties. The lower limit of the ethylene content is specifically limited, and the lower the ethylene content, the more easily the softness of the EVOH layer decreases, so it is preferably 25 mol% or more. In addition, the EVOH layer preferably contains an oxygen absorber. When the EVOH layer contains an oxygen absorber, the oxygen barrier properties of the EVOH layer can be further improved.

[0163] The melting point of the EVOH resin is preferably higher than the melting point of the random copolymer constituting the outer shell 21. The external air introduction hole 52 is preferably formed on the outer shell 21 using a heating hole-forming device. By setting the melting point of the EVOH resin to be higher than the melting point of the random copolymer, when the external air introduction hole 52 is formed on the outer shell 21, it is possible to prevent the hole from reaching the inner bag 22. From this point of view, it is preferred that the difference between (the melting point of EVOH) and (the melting point of the random copolymer layer) is large, preferably 15°C or more, and particularly preferably 30°C or more. The difference in the melting point is, for example, 5 to 50°C.

[0164] The inner layer is a layer in contact with the contents of the double-layer container 1, and is preferably composed of polyolefins such as low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymers and mixtures thereof, or is composed of low-density polyethylene or linear low-density polyethylene. The tensile modulus of the resin constituting the inner layer is preferably 50 to 300 MPa, more preferably 70 to 200 MPa. When the tensile modulus is within this range, the inner layer is particularly soft.

[0165] The adhesive layer is a layer having the function of bonding the EVOH layer and the inner surface layer, and can be, for example, an acid-modified polyolefin (e.g., maleic anhydride acid-modified polyethylene) and ethylene-vinyl acetate copolymer (EVA) added to the polyolefin as described above. An example of the adhesive layer is a mixture of low-density polyethylene or linear low-density polyethylene and acid-modified polyethylene.

[0166] In addition, it should be noted that the main body 2 has a flat shape as a whole. This structure can achieve the advantageous effect that the user can easily press and the contents can be easily squeezed out.

[0167] 1.2 Check valve 6

[0168] Next, the external air introduction hole 52 and the check valve 6 will be described. Fig.23 1 is a diagram showing an end face of the internal structure of the double-layer container 1 according to the first embodiment. Fig.23 The area surrounded by dotted lines has design features. Fig.24 The detailed structure of the check valve 6 is shown.

[0169] like Fig.23 As shown, the external air introduction hole 52 is provided in a specific area 51 on the bottom side of the housing 21. The bottom side here refers to the side away from the mouth 3 when the double-layer container 1 is divided into two equal parts in the height direction. In this embodiment, the specific area 51 is a part of the side surface of the housing 21. Specifically, the specific area 51 is located in the recess 5 of the housing 21.

[0170] The external air introduction hole 52 is configured to fit with the check valve 6. The check valve 6 may be, for example, a ball valve. The check valve 6 can introduce air into the intermediate space 25 inside the outer shell 21 and outside the inner bag 22 after the contents have flowed out, so that the shape of the outer shell 21 can be restored to its original state. In other words, the intermediate space 25 and the external space are connected to each other via the external air introduction hole 52.

[0171] Thus, the external air introduction hole 52 is provided in the specific area 51 on the bottom side of the outer shell 21, and when the contents are taken out, the external air is introduced into the intermediate space 25 from the upper side to the lower side through the external air introduction hole 52. That is, compared with the prior art, the inner bag 22 can be more effectively peeled off from the outer shell 21.

[0172] Next, the check valve 6 fitted in the external air introduction hole 52 will be described. Fig.24 A~ Fig.24As shown in FIG. 2 , the check valve 6 is a ball valve composed of a cylinder 60 and a ball 69. The cylinder 60 has a hollow portion 6s arranged to communicate with the external space and the intermediate space 25. The ball 69 is accommodated in the hollow portion 6s so as to be movable in a specific direction. Specifically, the diameter of the cross section of the hollow portion 6s is slightly larger than the diameter of the cross section corresponding to the ball 69, and the ball 69 has a shape that can be freely moved in a specific direction (here, the up and down direction of the paper).

[0173] The cylinder 60 has a shaft portion 61 disposed in the external air introduction hole 52, a stopper portion 62 disposed on the external space side of the shaft portion 61 and preventing the cylinder 60 from being inserted into the intermediate space 25, and an expanded diameter portion 63 disposed on the intermediate space 25 side of the shaft portion 61 and preventing the cylinder 60 from being pulled out from the outside of the main body 2. The shaft portion 61 is configured to have a shape (a tapered shape) with a tapered front end toward the intermediate space 25. The cylinder 60 is mounted on the main body 2 by the outer peripheral surface of the shaft portion 61 being in close contact with the edge of the external air introduction hole 52.

[0174] A stopper 65 is provided on the surface 66 surrounding the cavity 6s for engaging the ball 69 when the ball 69 moves from the intermediate space 25 side to the external space side. The stopper 65 is composed of an annular protrusion, and when the ball 69 contacts the stopper 65, the air flow through the cavity 6s is blocked.

[0175] The front end of the cylindrical body 60 is a flat surface 641 , and an opening 64 communicating with the cavity 6 s is provided on the flat surface 641 , and the cylindrical body 60 has a plurality of slits 642 radially extending from the opening 64 .

[0176] like Fig.24 As shown in FIG. 5 , when the check valve 6 is inserted into the external air introduction hole 52 from the side of the enlarged diameter portion 63 and the stopper portion 62 is pressed to a position in contact with the outer surface of the housing 21, the check valve 6 supports the housing 21 in a state where the outer peripheral surface of the shaft portion 61 is in close contact with the edge of the external air introduction hole 52. When the air enters the intermediate space 25 and compresses the housing 21, the air in the intermediate space 25 enters the cavity 6s through the opening 64 and pushes the ball 69 upward to abut against the stopper portion 65. When the ball 69 contacts the stopper portion 65, the air flow through the cavity 6s is blocked.

[0177] When the outer shell 21 is further compressed in this state, the pressure in the intermediate space 25 increases, resulting in the compression of the inner bag 22, and the contents are discharged from the storage space 26 in the inner bag 22. When the compression force on the outer shell 21 is released, the outer shell 21 returns to its original state due to its own elasticity. Fig.24 As shown in FIG. 2 , as the housing 21 returns to its original state, the pressure in the intermediate space 25 is reduced, and a force F is applied to the ball 69 toward the inner side of the container. As a result, the ball 69 moves toward the bottom surface of the hollow portion 6s, forming a Fig.24In the state shown in F, external gas (air) is introduced into the intermediate space 25 through the gap between the ball 69 and the surface 66 and the opening 64 .

[0178] The check valve 6 is a ball valve as described above, which is just an example and the present invention is not limited thereto. Any structure may be used as long as it can introduce external air into the intermediate space 25 and prevent backflow.

[0179] 1.3 Mouth 3 and cover 30

[0180] In the main body 2, the mouth 3 is configured to be able to install a cover 30 as a cover member. An external threaded portion is provided at the mouth 3, and a cover 30 having an internal thread is installed on the external threaded portion. The cover 30 is configured to use its top surface 31 as a grounding surface and can be placed inverted. Of course, the bottom surface 23 of the double-layer container 1 can also be used as a loading surface and placed upright. In order to be able to be inverted stably, in the double-layer container 1, the area of ​​the top surface 31 of the cover 30 is set to S1, and the area of ​​the mouth 3 is set to S2, then it is preferred to satisfy the following condition: S1 ≥ 1.5 × S2.

[0181] Specifically, when S1=k×S2, k=1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5 . 9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or a range between any two of the values ​​shown here. Since it can be placed in an inverted state, the residual rate can be suppressed even when a viscous substance such as jam, mayonnaise, or ketchup is contained as a contained object.

[0182] Reference again Fig.23, the specific area 51 is configured to have an inclination angle relative to the opening surface 53 of the concave portion 5. When the inclination angle is θ, in the double-layer container 1, the inclination angle θ can be 5 degrees or more and 45 degrees or less. Specifically, for example, θ=5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45 degrees, or a range between any two values ​​shown here.

[0183] With such an inclination angle θ, the outside air can be introduced more smoothly from the upper side to the lower side into the intermediate space 25. That is, such a structure helps to effectively peel the inner bag 22 from the outer shell 21.

[0184] The wall 54 defining the recess 5 is configured to be non-perpendicular to the opening surface 53. Assuming that the included angle is φ, the angle φ in the double-layer container 1 can be greater than 5 degrees and less than 75 degrees. Specifically, for example, φ=5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75 degrees, and the range between any two values ​​shown here may also be used. In addition, it is preferred that φ≥θ is satisfied.

[0185] With such an angle φ, it is possible to prevent the inner bag 22 from getting caught in the recess 5 (convex shape when viewed from the inner bag 22 side) when the inner bag 22 is peeled off from the outer case 21. In other words, this configuration helps to effectively peel the inner bag 22 from the outer case 21.

[0186] The double-layer container 1 further includes a groove portion 55. Specifically, the groove portion 55 is provided at a position closer to the bottom side than the specific area 51 on the outer shell 21. By providing such a groove portion 55, when drilling the external air introduction hole 52 with a drill in the license process, a fixing jig (not shown) having a convex portion and which can be accommodated in the groove portion 55 is used as a positioning reference. However, the depth of the groove portion 55 is preferably shallower than the depth of the concave portion 5. When a shrink film for marking the contents is attached to the outer side of the double-layer container 1, the dent is not noticeable, so it is beautiful in appearance.

[0187] 2. Second Embodiment According to the Second Aspect

[0188] In this section, a double container 1 according to a second embodiment will be described. Fig.25 1 is a perspective view of a double container 1 according to a second embodiment. Fig.26 It means from Fig.25 State The state after the cover 30 is removed. Fig. 27 Shown are a front view and a rear view of a double container 1 according to a second embodiment. Fig.28 It means from Fig. 27 Status: Status after cover 30 is removed. Fig.29 Shown are a left side view and a right side view of a double container 1 according to a second embodiment. Fig.30 It means from Fig.29 State The state in which the cover 30 is removed. Fig.31 Shown are a top view and a bottom view of a double container 1 according to a second embodiment. Fig.32 It means from Fig.31 Status: Status after cover 30 is removed. Fig.33 FIG. 2 is an end view showing the internal structure of the double-layer container 1 according to the second embodiment. Fig.33 The area surrounded by dotted lines has design features.

[0189] The double-layer container 1 according to the second embodiment has the same basic structure as the double-layer container 1 according to the first embodiment. Figure 25 to Figure 33 As shown, the difference lies in the shape of the main body 2. The bottom surface 23 (above the paper) of the double-layer container 1 in the second embodiment has a round shape, and it cannot stand when the bottom surface 23 is used as the placement surface. Therefore, the second embodiment is constructed based on the premise that the top surface 31 of the cover 30 is used as the placement surface.

[0190] In the double-layer container 1 according to the second embodiment, the extension surface of the specific region 51 is configured to intersect with the cutout 231 of the bottom surface 23. With this structure, the inner bag 22 tends to shrink with the cutout 231 as a fulcrum, thereby having an advantageous effect of not leaving the contents on the bottom side.

[0191] In the second embodiment, by providing the external air introduction hole 52 in the specific area 51 on the bottom side of the outer shell 21, after the contents are taken out, the external air is immediately introduced from the top to the bottom into the intermediate space 25 through the external air introduction hole 52. That is, compared with the prior art, the inner bag 22 can be more effectively peeled off from the outer shell 21.

[0192] 3. Conclusion

[0193] As described above, according to the embodiments described so far, a double-layer container can be realized, which can more effectively peel the inner bag from the outer shell after taking out the contents. It can also be implemented in various ways as described below. In the double-layer container, the mouth is configured to be able to install a lid, and the lid is configured to use its top surface as a grounding surface and can be placed inverted. In the double-layer container, let the area of ​​the top surface of the lid be S1, and the area of ​​the mouth be S2, which satisfies the following relationship: S1≥1.5×S2. In the double-layer container, the specific area is a part of the side surface of the outer shell. In the double-layer container, the specific area is located in the recess of the outer shell and is configured to have an inclination angle relative to the opening surface that defines the recess. In the double-layer container, the inclination angle is greater than 5 degrees and less than 45 degrees. In the double-layer container, the wall that defines the recess is configured to be non-perpendicular to the opening surface. In the double-layer container, a groove portion is further provided, and the groove portion is arranged closer to the bottom side than the specific area of ​​the outer shell. In the double-layer container, the depth of the groove portion is shallower than the depth of the recessed portion. In the double-layer container, the check valve is a ball valve. Of course, the present invention is not limited thereto.

[0194] (Third point of view)

[0195] 1. First embodiment of the third aspect

[0196] like Fig.34 As shown in FIG. 1 , a double-layer container 201 according to the first embodiment of the present invention includes a container body 202. Fig.36 As shown in A, the container body 202 has an outer shell 203 and an inner bag 204, and the inner bag 204 shrinks as the content decreases.

[0197] like Fig.34 As shown, the container body 202 includes a mouth 205, a body 206, and a bottom 207. The mouth 205 includes a snap-fit ​​portion 205a to which a pump not shown in the figure can be mounted. The snap-fit ​​portion 205a is an external threaded portion in the case of a threaded pump, and is an annular protrusion protruding in the circumferential direction in the case of a push-type pump. The mouth 205 is arranged to extend from the upper end portion 206a of the body 206. The mouth 205 is cylindrical. The outer diameter of the body 206 is larger than that of the mouth 205 (in this specification, when the cross section is not circular, the so-called "outer diameter" refers to the diameter of the circumscribed circle).

[0198] The body 206 is cylindrical, and the bottom 207 is provided at the lower end of the body 206 to close the lower end of the body 206. The bottom 207 includes a central recess 207a provided at the center of the bottom 207 and a peripheral edge 207b surrounding the central recess 207a.

[0199] like Fig.35As shown in FIG. 2A , the central recess 207a is provided with a locking portion 207a1, an external air introduction hole 207a2, an annular convex portion 207a3, and a positioning recess 207a4. Fig.36 As shown in FIG. 1A , the locking portion 207a1 is configured such that the locking protrusion 204a provided on the inner bag 204 is inserted into the insertion hole 203a provided on the outer shell 203. The locking portion 207a1 can prevent the inner bag 204 from being separated from the outer shell 203. The external air introduction hole 207a2 is a through hole that penetrates the outer shell 203. As the inner bag 204 contracts, the external air can be introduced into the intermediate space between the outer shell 203 and the inner bag 204 through the external air introduction hole 207a2. The locking portion 207a1 and the external air introduction hole 207a2 are arranged in the annular convex portion 207a3. The positioning recess 207a4 is used to position the container body 202 in the circumferential direction when the container body 202 is subjected to a process such as printing.

[0200] The peripheral portion 207b is provided with a grounding portion 207b1 and a peripheral recessed portion 207b2. The grounding portion 207b1 is a portion that contacts the mounting surface on which the container body 202 is mounted when the container body 202 is made to stand. If the peripheral portion 207b is used as the grounding portion 207b1 as a whole, when the container body 202 is made to stand, the central recessed portion 207a forms a closed space between the container body 202 and the mounting surface, which may cause the introduction of external gas through the external gas introduction hole 207a2 to be blocked. Therefore, the peripheral recessed portion 207b2 is provided as a gas passage to prevent the formation of a closed space in the central recessed portion 207a.

[0201] When the contents of the inner bag 204 are discharged by the pump installed on the mouth 205, the inner bag 204 shrinks and separates from the outer shell 203. At this time, external air can be introduced into the space between the inner bag 204 and the outer shell 203 through the external air introduction hole 207a2. Fig.36As shown in FIG. 1A, since the radius of curvature of the peripheral portion 207b is small, the inner bag 204 is not easily separated from the outer bag 203 at the peripheral portion 207b, and it is difficult to form a gas passage for the external gas introduced from the external gas introduction hole 207a2 to flow. Therefore, it is not easy to introduce external gas into the trunk 206. In this case, the problem of shrinking the outer bag 203 and the inner bag 204 together with the reduction of the content occurs. In this embodiment, a spacer 209 is arranged between the outer bag 203 and the inner bag 204. In this embodiment, a protrusion 203b protruding from the outer bag 203 to the inner bag 204 is provided as the spacer 209. When the spacer 209 is provided, a gap 208 is formed between the outer shell 203 and the inner bag 204 at a position adjacent to the spacer 209. The gap 208 can form a gas passage connecting the trunk 206 and the bottom 207, and the external gas introduced from the external gas introduction hole 207a2 can be easily introduced into the trunk 206 through the peripheral portion 207b. The spacer 209 is provided to radially span the bottom 207 and the trunk 206, and this structure easily forms a gas passage spanning the bottom 207 and the trunk 206.

[0202] like Figure 37 to Figure 39 As shown, the container body 202 can be formed by heating the inner preform 214 and the outer preform 213 and biaxially stretching blow molding the inner preform 214 and the outer preform 213 in a state where the inner preform 214 constituting the inner bag 204 covers the outer preform 213 constituting the outer shell 203 .

[0203] like Fig.37 As shown, the inner preform 214 is a bottomed cylindrical shape and includes a mouth 214a, a body 214b, and a bottom 214c. A flange 214a1 is provided at the open end of the mouth 214a. A positioning pin 214c1 is provided at the bottom 214c.

[0204] like Fig.37 As shown in FIG. 2 , the outer preform 213 is a bottomed cylindrical shape and includes a mouth 213a, a body 213b, and a bottom 213c. Fig.38 As shown, radially arranged protrusions 213c1 are provided on the inner surface of the bottom 213c of the outer preform 213. Positioning holes 213c2 and external air introduction holes 213c3 are provided on the bottom 213c. Fig.39 As shown in FIG. 2B , an annular protrusion 213c4 is provided on the outer surface of the bottom 213c. The positioning hole 213c2 and the external air introduction hole 213c3 are arranged in the area inside the annular protrusion 213c4. The outer preform 213 is sized to be inserted into the inner preform 214.

[0205] The inner preform 214 and the outer preform 213 can be formed by blow molding or injection molding of thermoplastic resins such as polyester (e.g., PET) and polyolefins (e.g., polypropylene, polyethylene). In one example, the inner preform 214 can be formed by blow molding of polypropylene, and the outer preform 213 can be formed by injection molding of PET. By making the materials of the inner preform 214 and the outer preform 213 different, it is possible to suppress welding to each other during blow molding. In addition, when the outer preform 213 is formed by injection molding, the external air introduction hole 213c3 can be formed during injection molding, thereby saving time spent on post-processing.

[0206] 2. Biaxial stretch blow molding

[0207] Biaxial stretch blow molding can be performed by the following method.

[0208] First, if Fig.39 As shown, the outer preform 213 is covered on the inner preform 214 (in other words, the inner preform 214 is inserted into the outer preform 213) to form an assembly 215. At this time, the flange 214a1 contacts the open end of the mouth 213a, and the positioning pin 214c1 is inserted into the positioning hole 213c2. Thus, the inner preform 214 and the outer preform 213 are positioned relative to each other. In this state, the mouth 214a and the mouth 213a are opposite to each other, and the body 214b and the body 213b are opposite to each other.

[0209] Then, the softening assembly 215 is heated.

[0210] Subsequently, the assembly 215 is placed in a blow molding mold, and air is blown into the inner preform 214 while the mouth 213a and the annular protrusion 213c4 are supported by a clamp to expand the assembly 215 and closely fit the inner surface of the mold cavity. At this time, the shaking of the assembly 215 in the mold can be suppressed by pressing a support rod (not shown) against the inner bottom surface of the inner preform 214. In addition, a recessed portion for engaging the support rod can be provided on the inner bottom surface of the inner preform 214 so that the support rod can be easily fixed in the inner preform 214.

[0211] By blow molding, the component 215 is expanded to a size such as Figure 34 to Figure 36The container body 202 is shown. The mouth 213a, 214a becomes the mouth 205, the body 213b, 214b becomes the body 206, and the bottom 213c, 214c becomes the bottom 207. The protrusion 213c1, the annular convex portion 213c4 and the external air inlet hole 213c3 become the protrusion 203b, the annular convex portion 207a3 and the external air inlet hole 207a2 respectively. During blow molding, the mouth 213a, 214a, the annular convex portion 213c4 and the area inside thereof are almost not deformed, and deformation mainly occurs in other parts. The external air inlet hole 213c3 is arranged in the inner area of ​​the annular convex portion 213c4, so that it can be prevented from being blocked by deformation during blow molding. The flange 214a1 is as shown Fig.34 Indicated by A is a flange 204 b which covers the open end of the mouth portion 205 of the container body 202 .

[0212] After blow molding, the positioning hole 213c2 becomes as follows Fig.36 A is inserted into the insertion hole 203a, and the positioning pin 214c1 is formed to be inserted into the insertion hole 203a. Then, the positioning pin 214c1 is deformed (ie, flattened or bent) to form a Fig.36 The locking protrusion 204a is shown as A. Thus, the locking portion 207a1 of the container body 202 is formed.

[0213] 3. Details of biaxial stretch blow molding

[0214] In the above-mentioned biaxial stretch blow molding, for example, Figure 40 to Figure 42 The die unit 220 shown in the figure is used for the production. The die unit 220 includes a mouth support die 221, a bottom support die 222, and forming dies 223 and 224.

[0215] The mouth support mold 221 is configured to support the mouth 213a of the outer preform 213. An insertion hole 221a is provided in the mouth support mold 221, and a support rod 225 is inserted into the insertion hole 221a. The support rod 225 can be extended and retracted by a driving mechanism (not shown). The bottom support mold 222 is configured to be driven by a driving mechanism 222c and can be extended and retracted in the longitudinal extension direction ( Fig.40 The forming molds 223 and 224 can be opened and closed, and have cavity surfaces 223a and 224a, respectively. The cavity surfaces 223a and 224a are closed to form a cavity having a shape corresponding to the outer shape of the container body 202.

[0216] This method includes a preform heating step, a bottom supporting step, a stretching step, and a blow molding step.

[0217] <Preform heating process>

[0218] In the preform heating process, the inner preform 214 covers the outer preform 213 to form an assembly 215. Fig.40 The assembly 215 is installed on the mouth support mold 221 in the manner shown, and in this state, the assembly 215 is heated to soften it. The assembly 215 can be heated in a state where the assembly 215 is arranged between the forming molds 223 and 224, or it can be heated outside the space between the forming molds 223 and 224. In addition, before the preform heating step, the front end of the support rod 225 can also be abutted against the inner bottom surface of the inner preform 214. This can suppress the shaking of the softened assembly 215.

[0219] <Bottom support process>

[0220] In the bottom support process, Fig.41 As shown, the bottom support mold 222 moves toward the bottom 213c of the outer preform 213, and the bottom support mold 222 supports the bottom 213c of the outer preform 213. A recess 222a that can accommodate the annular protrusion 213c4 is provided on the bottom support mold 222, and the bottom support mold 222 preferably supports the bottom 213c in a manner that the annular protrusion 213c4 is accommodated in the recess 222a. In this way, the annular protrusion 213c4 and the inner area can be prevented from being extended during the blow molding process. The recess 222a is preferably annular. The bottom support mold 222 has a recess 222b that can accommodate the positioning pin 214c1, and preferably supports the bottom 213c in a manner that the positioning pin 214c1 is accommodated in the recess 222b. In this way, the positioning pin 214c1 can be prevented from interfering with the bottom support mold 222. Although Fig.41 The figure shows the state where the forming dies 223 and 224 are closed, but the forming dies 223 and 224 only need to be closed at any time point before the blow molding process, and can also be made to be closed after the longitudinal stretching process.

[0221] <Vertical stretching process>

[0222] In the longitudinal stretching process, Figure 41-42 As shown, the assembly 215 can be extended in the longitudinal direction ( Fig.42 At this time, it is preferred that the bottom support mold 222 is moved backward synchronously with the extension of the support rod 225. This allows the assembly 215 to be stabilized and extended. It should be noted that the longitudinal extension process can be performed without using the bottom support mold 222 to support the bottom 213c, or the bottom support process can be performed after the longitudinal extension process.

[0223] <Blow molding process>

[0224] In the blow molding process, Fig.42 In the state shown, air is blown into the inner preform 214 to extend the assembly 215 laterally (i.e., expand it) and give the cavity surfaces 223a, 224a a shape. The air can be blown in through the air passage 226 between the mouth support mold 221 and the support rod 225, or by providing a gas passage in the support rod 225 and blowing air out from the side of the support rod 225.

[0225] In the present embodiment, since air is blown into the bottom 213 c of the outer preform 213 while being supported by the bottom support die 222 , it is possible to suppress the bottom 213 c of the outer preform 213 from extending.

[0226] It should be noted that the blow molding process can be performed simultaneously with the longitudinal stretching process. That is, the component 215 can be longitudinally stretched while air is blown into the inner preform 214. In addition, the longitudinal stretching process can be omitted, and the component 215 is not longitudinally stretched after the bottom support process, and only air is blown.

[0227] 4. Other implementation methods

[0228] ・In the above embodiment, the spacer 209 is arranged in a radial shape, but the spacer 209 may also be in other shapes. For example, the spacer 209 may be arranged in a discontinuous circle. In this case, a gas passage is formed at the position of the notch of the circle. The discontinuous circle is preferably arranged in a concentric circle shape. Fig.43 As shown, such a spacing member 209 may be formed by using an outer preform 213 having a non-continuously rounded protrusion 213c1.

[0229] In the above embodiment, the protrusion 213c1 is provided on the outer preform 213 to form the protrusion 203b protruding from the outer shell 203 to the inner bag 204. Figure 44-45 As shown, the bottom 214c of the inner preform 214 may also be provided with a protrusion 214c2 (for example, as shown in FIG. Fig.44 The radial protrusions shown, or Fig.45 The protrusion (spacer member) protruding from the inner bag 204 toward the outer shell 203 is formed by using the discontinuous circular protrusion shown in FIG.

[0230] The partition member 209 may be formed of another member. The partition member 209 between the outer shell 203 and the inner bag 204 may be disposed by blow molding in a state where a member serving as the partition member is disposed between the inner preform 214 and the outer preform 213 .

[0231] 5. Inventions from other perspectives

[0232] When the inner preform 214 is a blow molded body (specifically, a direct blow molded body), as Fig.46 As shown, a cut portion 214h is formed at the position where the bottom 214g of the inner preform 214 blocks the parison. Since the strength of the cut portion 214h is relatively weak, when the area near the cut portion 214h is strongly stretched during biaxial stretch blow molding, the cut portion 214h may crack.

[0233] In one example, if Fig.46 As shown, the inner preform 214 is a multi-layer structure, which has an innermost layer 214d, a gas barrier layer (e.g., EVOH layer) 14e, and an outermost layer 214f ​​in order from the inside. The innermost layer 214d and the outermost layer 214f ​​can be composed of polyolefins (e.g., polyethylene, polypropylene) and PET. At the cut embryo part 214h, even if the opposing gas barrier layers 214e1 and 214e2 are connected or separated from each other, the gap G between them becomes very small. When the part near the cut embryo part 214h is stretched vigorously during biaxial stretch blow molding, the gas barrier layer 214e may crack or the gap G may become larger, thereby causing problems such as poor gas barrier properties.

[0234] As described in "2. Biaxial stretch blow molding" and "3. Details of biaxial stretch blow molding", the above-mentioned problem can be solved by expanding the assembly 215 while suppressing the extension of the bottom 213c of the outer preform 213. Since the cut embryo part 214h is arranged at a position opposite to the bottom 213c of the outer preform 213, when the extension of the bottom 213c is suppressed, the extension of the part near the cut embryo part 214h can also be suppressed, thereby solving the above-mentioned problem.

[0235] In "2. Biaxial stretch blow molding", the rigidity of the bottom 213c can be increased and the elongation of the bottom 213c can be suppressed by providing the annular protrusion 213c4 on the bottom 213c of the outer preform 213. The structure provided to improve the rigidity of the bottom 213c may be a reinforcement structure other than the annular protrusion 213c4.

[0236] In "3. Details of Biaxial Stretch Blow Molding", the bottom 213c of the outer preform 213 is supported by the bottom support mold 222, and the blow molding process is performed in this state to suppress the extension of the bottom 213c. In the above description, although the annular convex portion 213c4 is accommodated in the concave portion 222a, even if there is no annular convex portion 213c4 in the bottom 213c, the bottom 213c can be supported by the bottom support mold 222, and the friction between the bottom 213c and the bottom support mold 222 can be used to suppress the extension of the bottom 213c.

[0237] Taking the above into consideration, the present invention provides a method for manufacturing a double-layer container, which has a blow molding process, wherein the blow molding process is performed by heating the inner preform and the outer preform to soften them in a state where the inner preform covers the outer preform, and blowing air into the inner preform in this state, wherein the inner preform is a blow-molded body, and the blow molding process is performed in a state where the bottom extension of the outer preform is suppressed.

[0238] It is preferable that the outer preform includes a reinforcement structure for suppressing extension of the bottom portion of the outer preform.

[0239] Preferably, the reinforcement structure is an annular protrusion provided on the bottom of the outer preform.

[0240] The blow molding step is preferably performed by supporting the bottom of the outer preform with a bottom supporting mold and suppressing extension of the bottom.

[0241] In addition, in another viewpoint, a method for manufacturing a double-layer container is provided, which comprises a blow molding process, wherein the blow molding process is completed by heating the inner preform and the outer preform while the inner preform covers the outer preform, and blowing air into the inner preform to soften the inner preform, wherein the inner preform is a blow-molded body and the outer preform has an annular convex portion at the bottom.

[0242] It should be noted that in other aspects of the invention, the position of the external air introduction hole is not limited, and it can be set in any of the mouth 205, the body 206, and the bottom 207 of the container body 202. In addition, the spacer member 209 for forming a gap between the outer shell 203 and the inner bag 204 is not essential.

[0243] [Example]

[0244] Hereinafter, examples related to the first aspect will be described.

[0245] 1. Manufacturing of the container body 102

[0246] <Example 1>

[0247] Direct blow molding and the layer composition shown in Table 3 were used to manufacture Fig.12 The inner container 104 having the structure shown has a wall thickness of 1500 μm at the center of the housing portion 107 in the height direction of the inner container 104.

[0248]

Table 3

[0249]

[0250] The layers in Table 3 were made of the following materials.

[0251] LDPE / LLDPE layer: a mixed resin of LDPE (melting point 110°C, manufactured by Asahi Kasei Corporation, model: F2206) and LLDPE (melting point 120°C, manufactured by Japan Polyethylene Co., Ltd., model: NF325N) with a mass ratio of 50:50

[0252] PP layer: Polypropylene (manufactured by Sumitomo Chemical Co., Ltd., model: FH3315)

[0253] EVOH layer: EVOH (manufactured by Mitsubishi Chemical Corporation, model: SF7503B)

[0254] Acid-modified PE / LDPE layer: A mixed resin of acid-modified polyethylene (Mitsubishi Chemical Corporation, model: L522) and LDPE (melting point 110°C, Asahi Kasei Corporation, model: F2206) in a mass ratio of 50:50

[0255] LDPE layer: LDPE (manufactured by Asahi Kasei Corporation, model: F2206)

[0256] Next, according to the method described in the first embodiment, the outer cover 105 is formed by injection molding at a resin temperature of 220° C. to manufacture the container body 102 so as to cover the outer peripheral surface and the bottom surface of the inner container 104. For the injection molding, an ionomer resin of an ethylene-(meth)acrylic acid copolymer (manufactured by Dow-Mitsui Polychemicals, model: PC2000, melting point 80° C.) is used.

[0257] <Example 2>

[0258] The container body 102 was produced by the same method as in Example 1 except that an LDPE / ADH layer was used instead of the LDPE / LLDPE layer as the outermost layer 113 c 1 of the outer shell 113 .

[0259] The LDPE / ADH layer is a mixed resin of LDPE (melting point 110°C, manufactured by Asahi Kasei Corporation, model: F2206) and an adhesive resin (melting point 120°C, manufactured by Mitsubishi Chemical Corporation, model: L522) in a mass ratio of 50:50, and the melting point of the mixed resin is 115°C.

[0260] <Comparative Example 1>

[0261] The container body 102 was produced in the same manner as in Example 1 except that a PP layer was used instead of the LDPE / LLDPE layer as the outermost layer 113 c 1 of the outer shell 113 .

[0262] The PP layer is composed of polypropylene (manufactured by Sumitomo Chemical Co., Ltd., model: FH3315) having a melting point of 140°C.

[0263] 2. Evaluation

[0264] The following evaluations were performed on the above-mentioned Examples and Comparative Examples, and the results are shown in Table 4. As shown in Table 4, in the Examples, the deformability and adhesiveness were good. In contrast, the deformability and adhesiveness of the Comparative Examples were poor.

[0265]

Table 4

[0266]

[0267] <Deformability>

[0268] Whether the inner container 104 in the outer casing 105 is deformed was visually checked and evaluated according to the following criteria.

[0269] ○: No deformation

[0270] ×: Deformation

[0271] <Adhesion>

[0272] The container body 102 was cut longitudinally to confirm whether the inner container 104 could be peeled off from the outer cover 105 by hand, and the evaluation was performed according to the following criteria.

[0273] ○: Will not peel off even if pulled hard by hand

[0274] △: It can be peeled off by pulling it hard with your hands

[0275] ×: Can be easily peeled off by hand

[0276] (Explanation of symbols)

[0277] 1: double-layer container, 2: main body, 3: mouth, 5: recess, 6: check valve, 6s: cavity, 21: outer shell, 22: inner bag, 23: bottom surface, 25: intermediate space, 26: storage space, 30: lid, 31: top surface, 51: specific area, 52: external air introduction hole, 53: opening surface, 54: wall, 55: groove, 60: cylinder, 61: shaft, 62: stopper, 63: expansion part, 64: opening, 65: stopper, 66: surface, 69: ball, 101: storage container, 102: container main body, 103: plug opening member, 104: inner container, 104a: outer peripheral surface, 104b: bottom surface, 104c1: outermost layer, 104c2: adjacent layer, 104c3: other layers, 10 5: outer sleeve, 105a: barrel, 105b: bottom, 105c: ventilation, 107: storage, 107a: trunk, 107b: bottom, 107c: pinch-off, 108: mouth, 108a: engagement, 108b: flat, 109: mold, 109a: cavity, 109b: gate, 110: fixing, 110a: opening, 111: support rod, 112: pump, 112a: main body, 112a1: barrel, 112a2: cylinder, 112a3: upper wall, 112b: piston, 112c: nozzle, 112d: tube, 113: outer shell, 113c1: outermost layer, 113c2: adjacent layer, 113c3: other layers, 114: inner bag, 114c 1: Outermost layer, 114c2: Adhesive layer, 114c3: Inner layer, 115: External air inlet, 201: Double-layer container, 202: Container body, 203: Outer shell, 203a: Insertion hole, 203b: Protrusion, 204: Inner bag, 204a: Stopping protrusion, 204b: Flange, 205: Mouth, 205a: Locking part, 206: Body, 206a: Upper end, 207: Bottom, 207a: Central concave part, 207a1: Stopping part, 207a2: External air inlet hole, 207a3: Annular convex part, 207a4: Positioning concave part, 207b: Peripheral part, 207b1: Grounding part, 207b2: Peripheral concave part, 208: Gap, 209: Spacer, 213: External preform Blank, 213a: mouth, 213b: body, 213c: bottom, 213c1: protrusion, 213c2: positioning hole, 213c3: external air introduction hole, 213c4: annular convex portion, 214: inner preform, 214a: mouth, 214a1: flange, 214b: body, 214c: bottom, 214c1: positioning pin, 214c2: protrusion, 214d: innermost layer, 214e: gas barrier layer, 214e1: gas barrier layer, 214e2: gas barrier layer, 214f: outermost layer, 214g: bottom, 214h: blank cutting part, 215: assembly, 220: mold unit, 221: mouth support mold, 221a: insertion hole, 222: bottom support mold, 222a: recess,222b: concave part, 222c: driving mechanism, 223: forming die, 223a: cavity surface, 224: forming die, 224a: cavity surface, 225: support rod, 226: gas passage, 231: cut embryo, 641: flat surface, 642: slit part, A: area, B: area, C: area, F: force, G: gap, Tpm: melting peak temperature, θ: tilt angle, φ: angle.

Claims

1. A storage container comprising a container body integrally formed with an outer sleeve so as to cover an outer peripheral surface of an inner container, The outer shell is an injection molded body, The inner container is a blow-molded body formed by blow molding a parison. The inner container comprises an outermost layer and an adjacent layer adjacent to the outermost layer, The melting point of the outermost layer resin constituting the outermost layer is lower than the melting point of the adjacent layer resin constituting the adjacent layer, The resin constituting the outer shell has the same monomer units as the outermost layer resin, The melting point of the resin constituting the outer cover is lower than the melting point of the resin of the outermost layer.

2. The storage container according to claim 1, wherein: The difference between the melting point of the outermost layer resin and the melting point of the adjacent layer resin is 5° C. or more.

3. The storage container according to claim 1 or 2, wherein: The wall thickness of the outermost layer is 10% or more relative to the wall thickness of the inner container.

4. The storage container according to claim 1 or 2, wherein: The outermost layer resin contains unmodified polyolefin.

5. The storage container according to claim 4, wherein: The outermost layer resin contains an acid-modified polyolefin and the unmodified polyolefin.

6. The storage container according to claim 1 or 2, wherein: The inner container is constructed to have an outer shell and an inner bag, and the inner bag shrinks as the content decreases. The outermost layer and the adjacent layer are disposed on the outer shell.

7. The storage container according to claim 6, wherein: An external air introduction portion is provided to introduce external air between the outer shell and the inner bag. The outer sleeve is provided with a vent portion communicating with the external air introduction portion.

8. A method for manufacturing a storage container, comprising an integral molding step of integrally molding an inner container and an outer casing, In the integral molding step, the outer shell is formed by filling a space outside the inner container in the cavity of the mold with resin while the outer peripheral surface of the inner container is arranged in the mold. The inner container is a blow-molded body formed by blow molding a parison. The inner container comprises an outermost layer and an adjacent layer adjacent to the outermost layer, The melting point of the outermost layer resin constituting the outermost layer is lower than the melting point of the adjacent layer resin constituting the adjacent layer, The resin constituting the outer shell has the same monomer units as the outermost layer resin, The melting point of the resin constituting the outer cover is lower than the melting point of the resin of the outermost layer.

9. The manufacturing method according to claim 8, wherein: The inner container is constructed to have an outer shell and an inner bag, and the inner bag shrinks as the content decreases. The outermost layer and the adjacent layer are disposed on the outer shell.

10. The manufacturing method according to claim 9, wherein: An external air introduction portion is provided to introduce external air between the outer shell and the inner bag. The outer sleeve is provided with a vent portion communicating with the external air introduction portion.

11. The production method according to any one of claims 8 to 10, wherein During the integral molding step, the inner container is pressurized.

12. The production method according to any one of claims 8 to 10, wherein: In the integral molding step, the resin is filled in a state where the inner surface of the bottom surface of the inner container is pressed using a support rod inserted into the inner container.

13. The manufacturing method according to claim 11, wherein: In the integral molding step, the resin is filled in a state where the inner surface of the bottom surface of the inner container is pressed using a support rod inserted into the inner container.

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