TW202126541A - Container and method for producing same, and double-walled container and method for producing same - Google Patents

Abstract

The present invention provides a container which has an exceptional appearance. The present invention provides a container which is provided with a container main body that is integrally molded with an outer cover in such a manner that the outer peripheral surface of an inner container is covered by the outer cover, wherein: the outer cover is an injection molded body; the inner container comprises an outermost layer and an adjacent layer that is adjacent to the outermost layer; and the melting point of an outermost layer resin that constitutes the outermost layer is lower than the melting point of an adjacent layer resin that constitutes the adjacent layer.

Description

Containment container and manufacturing method thereof, double-layer container and manufacturing method thereof

The present invention relates to a storage container capable of containing contents and a manufacturing method thereof, as well as a double-layer container and a manufacturing method thereof.

(1st point of view) Nowadays, there is known a laminated peeling container (for example, Patent Document 1) that reduces the shrinkage of the inner bag with the contents and prevents air from entering the inside of the container.

(2nd point of view) There is known a double-layer container (laminated peeling container) that has an outer shell and an inner bag and can contain contents in the inner bag (for example, Patent Document 2). The outer shell can be pressed from the outside, and the contents contained in the inner bag flow out from the mouth by this pressing. After pressing, air is introduced between the outer shell and the inner bag through a check valve provided on the outer shell, so that the shape of the outer shell is restored, and the inner bag gradually shrinks.

(3rd viewpoint) Patent Document 3 discloses a method of manufacturing a double-layer container by blow molding in a state where the inner preform and the outer preform are overlapped. [Advanced Technical Document] [Patent Document]

Patent Document 1: Japanese Patent Application Publication No. 2015-163531 Patent Document 2: Japanese Patent Application Publication No. 2018-087036 Patent Document 3: International Publication No. 2004/071887

[The problem to be solved by the invention]

(1st point of view) The laminated peeling container of Patent Document 1 is constructed by covering the outer peripheral surface of a container formed by blow molding with a shrink film, but there are cases in which an appearance design that can express a sense of luxury is required.

The present invention has been completed in view of the above circumstances, and it provides a storage container with an excellent appearance.

(2nd point of view) However, in the prior art described in Patent Document 2, since the air introduction hole through which the check valve is inserted is located near the mouth, it is necessary to introduce air from the lower to the upper side of the container immediately after the contents are taken out, so the efficiency is not good.

The present invention has been completed in view of the above circumstances, and its object is to provide a double-layered container in which the inner bag is more effectively peeled from the outer shell after the contents are taken out.

(3rd viewpoint) The inner bag is formed by the inner preform, and the outer shell is formed by the outer preform. As the content of the inner bag reduces the shrinkage of the inner bag, the outer air is introduced into the intermediate space between the inner bag and the outer shell from the outer air introduction hole provided in the outer shell, and the outer shell can maintain its original state.

In this double-layer container, the inventors of the present invention took into consideration factors such as aesthetics, and found that when the external air introduction hole is provided at the bottom of the container, it is sometimes difficult for external air to be introduced into the intermediate space between the inner bag and the outer shell.

The present invention has been completed in view of the above circumstances, 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 when the external air introduction hole is provided at the bottom of the container body. [Technical Solution to Problem]

(1st point of view) According to the present invention, there is provided a storage container including a container body integrally formed with a jacket to cover the outer peripheral surface of the inner container, the jacket being an injection-molded body, and the inner container having an outermost layer adjacent to the outermost layer In the adjacent 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 storage container of the present invention has an excellent appearance because the outer casing composed of an 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 deformation of the inner container. In addition, since the melting point of the outermost layer resin is lower than that of the adjacent layer resin, the adhesion between the outermost layer and the outermost layer is improved, and the adhesion between the outer peripheral surface of the inner container and the outer layer caused by impact such as drop is suppressed. Peel off.

Hereinafter, various embodiments of the present invention will be listed. The embodiments shown below can be combined with each other. 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. Preferably, the wall thickness of the outermost layer is 10% or more with respect to the wall thickness of the inner container of the storage container. Preferably, the outermost layer resin of the storage container contains unmodified polyolefin. Preferably, the outermost layer resin of the storage container contains acid-modified polyolefin and the unmodified polyolefin. It is preferable that the resin constituting the outer shell of the storage container has the same monomer unit as the outermost layer resin. Preferably, the inner container of the storage container is configured to have 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. Preferably, the method of manufacturing the storage container includes an integral molding step of integrally molding the inner container and the outer jacket, and in the integral molding step, the outer peripheral surface of the inner container is disposed in the mold, and the inner container is placed in the cavity of the mold The outer space of the inner container is filled with resin to form the outer casing, the inner container includes an outermost layer, an adjacent layer adjacent to the outermost layer, and a melting point ratio of the outermost resin constituting the outermost layer constitutes the adjacent The resin of the adjacent layer of the layer has a low melting point. Preferably, the method pressurizes the inner container during the integral molding step. Preferably, in the integral molding step of the method, the resin is filled while pressing the inner surface of the bottom surface of the inner container with a support rod inserted into the inner container.

(2nd point of view) According to an aspect of the present invention, there is provided a double-layer container including an outer shell, an external air introduction hole, and an inner bag. Outflow from the mouth, the external air introduction hole is provided in a specific area on the bottom side of the housing, and the bottom side refers to the side away from the mouth when the double-layer container is divided into two in the height direction, and constitutes In order to fit with the check valve, after the content flows out through the check valve, air is introduced into the intermediate space between the inner side of the casing and the outer side of the inner bag to restore the shape of the casing, The inner bag is configured such that when the content decreases, the air introduced into the intermediate space is compressed and contracted.

With the specific area provided with the air introduction hole provided on the bottom side of the outer shell, the double-layer container has an advantageous effect that the inner bag can be effectively peeled from the outer shell immediately after taking out the contents.

(3rd viewpoint) According to the present invention, there is provided a double-layer container including a container body configured to have an outer shell and an inner bag and reduce the shrinkage of the inner bag with the contents, the container body having a cylindrical body part and a lower end of the body part. The bottom part is provided with a central recess provided in the center of the bottom and a peripheral part surrounding the central recess. In the central recess, an external air introduction hole is provided in the housing, and the peripheral part is provided for A spacer member that forms a gap between the outer shell and the inner bag.

The present invention conducted a detailed study 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 edge portion surrounding the central recess. Therefore, when an external air introduction hole is provided in the central recess, it is difficult to form a gap. It is easy to introduce external air into the body of the container body. In addition, based on this finding, by providing a spacer for forming a gap between the outer shell and the inner bag, the external air can be smoothly introduced from the external air introduction hole at the bottom to the carcass through the peripheral portion, thereby completing the present invention .

Hereinafter, various embodiments of the present invention will be listed. The embodiments shown below can be combined with each other. Preferably, the spacing member of the double-layer container is a protrusion provided on the outer shell or the inner bag. Preferably, the partition member of the double-layer container is arranged radially. Preferably, the partition member of the double-layer container is arranged to form a discontinuous circle. Preferably, the container body of the double-layer container covers the inner preform constituting the inner bag with the outer preform constituting the outer preform, and the inner preform and the outer preform are The billet is heated for blow molding. Preferably, the inner preform of the double-layer container is provided with a positioning pin at the bottom of the inner preform, the outer preform is provided with a positioning hole at the bottom of the outer preform, and the blow molding The forming is performed in a state where the positioning pin is inserted into the positioning hole. [Illustration brief description]

FIG. 1 is a perspective view of the storage container 101 according to the first embodiment in the first aspect. FIG. 2 is a perspective view of the container main body 102. FIG. 3 is a cross-sectional view of the container main body 102. FIG. 4 shows the layer structure of the container body 102 in the area A in FIG. 3. FIG. 5 is a perspective view of the inner container 104. FIG. 6 is a cross-sectional view of the inner container 104. Fig. 7 is a cross-sectional view for explaining the integral molding step. Fig. 8 is an enlarged view of the area B in Fig. 7. 9A to 9B are perspective views when the storage container 101 according to the second embodiment is viewed from different directions. Fig. 10 is a cross-sectional view of the container body 102 of Fig. 9A. FIG. 11 shows the layer structure of the container body 102 in the area C in FIG. 10. FIG. 12 is a cross-sectional view showing only the inner container 104 in FIG. 10. FIG. 13 is a perspective view of the pump 112. FIG. 14 is an enlarged view showing the vicinity of the mouth portion 108 of FIG. 5 in a state where the outside air introduction portion 115 is provided in the mouth portion 108 of the inner container 104 in the third embodiment. FIG. 15 is a perspective view showing the double container 1 according to the first embodiment in the second aspect. FIG. 16 shows the state after the cover 30 is removed from the state of FIG. 15. FIG. 17 shows a front view and a back view of the double-layer container 1 according to the first embodiment in the second aspect. FIG. 18 shows the state after the cover 30 is removed from FIG. 17. FIG. 19 shows a left side view and a right side view of the double-layer container 1 according to the first embodiment in the second aspect. FIG. 20 shows the state after the cover 30 is removed from the state of FIG. 19. FIG. 21 shows a top view and a bottom view of the double-layer container 1 according to the first embodiment in the second aspect. Fig. 22 shows the state in which the cover 30 is removed from the state in Fig. 21. FIG. 23 shows an end view of the internal structure of the double container 1 according to the first embodiment in the second aspect. FIG. 24 shows the detailed structure of the check valve 6. FIG. 25 shows a perspective view of the double-layer container 1 according to the second embodiment in the second aspect. FIG. 26 shows the state after the cover 30 is removed from the state of FIG. 25. FIG. 27 shows a front view and a back view of the double-layer container 1 according to the second embodiment from the second viewpoint. FIG. 28 shows the state in which the cover 30 is removed from the state in FIG. 27. FIG. 29 shows a left side view and a right side view of the double-layer container 1 according to the second embodiment from the second viewpoint. FIG. 30 shows the state after the cover 30 is removed from the state of FIG. 29. FIG. 31 shows a top view and a bottom view of the double-layer container 1 according to the second embodiment from the second viewpoint. Fig. 32 shows the state in which the cover 30 is removed from the state of Fig. 31. FIG. 33 is an end view showing the internal structure of the double container 1 according to the second embodiment in the second aspect. FIG. 34 shows the container body 202 of the double-layer container 201 according to the first embodiment of the third aspect of the present invention. FIG. 34A is a front view, and FIG. 34B is a bottom view. 35A is a perspective view of the container main body 202 of FIG. 34 seen from the bottom 207, and FIG. 35B is a cross-sectional perspective view of the vicinity of the bottom 207 of the housing 203 seen from the inside of the container. Fig. 36A is a cross-sectional view of A-A in Fig. 34B, and Fig. 36B is a cross-sectional view of B-B in Fig. 36A. FIG. 37 shows a perspective view of a state where the inner preform 214 and the outer preform 213 are separated. FIG. 38 is a cross-sectional perspective view of the vicinity of the bottom portion 213c of the outer preform 213 of FIG. 37 as viewed from the inside of the outer preform 213. FIG. FIG. 39A is a perspective view of the assembly 215 formed by covering the outer preform 213 on the inner preform 214, and FIG. 39B is a perspective view of FIG. 39A when viewed from another angle. FIG. 40 shows a biaxial stretch blow molding step, which is a cross-sectional view of a state in which the assembly 215 is attached to the mouth support mold 221. As shown in FIG. 41 is a cross-sectional view of a state where the forming molds 223 and 224 are closed from the state of FIG. 40 and the bottom support mold 222 supports the bottom 213c of the outer preform 213. 42 is a cross-sectional view of the state in which the support rod 225 is extended from the state of FIG. 41 and the bottom support mold 222 is retracted to extend the assembly 215 in the longitudinal direction. FIG. 43 shows an outer preform 213 having a non-continuous circular protrusion 213c1, which is a cross-sectional perspective view corresponding to FIG. 38. FIG. 44 shows a perspective view of the inner preform 214 having a configuration in which radial protrusions 214c2 are provided on the bottom portion 214c. FIG. 45 is a perspective view of the inner preform 214 showing a configuration in which protrusions 214c2 having a discontinuous circle are provided on the bottom portion 214c. FIG. 46 is an enlarged view of the vicinity of the bottom portion 214g of the inner preform 214 of the modification.

The following describes the embodiments of the present invention. Various characteristic items shown in the embodiments shown below can be combined with each other. Also, each feature can independently constitute the present invention.

(1st point of view) 1. The first embodiment As shown in FIG. 1, the storage container 101 according to the first embodiment of the present invention includes a container main body 102 and a cap opening member 103 having a flat top surface. The plug opening member 103 may be a pump, a hinged cover, or the like. As shown in FIG. 3, the container main body 102 includes an inner container 104 and an outer casing 105 integrally formed therewith. Each configuration will be described below.

＜Inner container 104＞ The inner container 104 shown in FIGS. 5 to 6 may be a container formed by any manufacturing method, and among them, a blow-molded container formed by blow molding with a parison is preferable. Blow molding can be direct blow molding or injection blow molding. In direct blow molding, a pair of split dies are used to clamp a molten parison extruded from an extruder, and air is blown into the parison to manufacture a container. The parison can be cylindrical or sheet-shaped. In injection blow molding, a test tube-shaped bottomed parison called a preform is formed by injection molding, and then the parison is blow molded to manufacture a container.

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

The inner container 104 has a bottomed cylindrical shape, and includes a storage portion 107 for storing contents and a mouth portion 108 for discharging the contents from the storage portion 107. The accommodating portion 107 includes a body portion 107a and a bottom portion 107b. The mouth 108 is provided with an engaging portion (male screw portion) 8a, so that the plug opening member 103 can be attached.

When the inner container 104 is formed by direct blow molding, the inner container 104 has a pinch-off portion 107c (as shown in FIG. 6) formed by extruding a parison with a pair of split dies. The pinch-off portion 107c is provided at the bottom 107b of the inner container 104, and at the pinch-off portion 107c, the bottom of the inner container 104 is closed by welding the opposing surfaces of the parison to each other. The shape of the receiving portion 107 may be various shapes such as a cylindrical shape, a polygonal prism shape, a polygonal pyramid shape, and a spherical shape.

As shown in FIG. 4, the inner container 104 includes an outermost layer 104c1, an adjacent layer 104c2, and another layer 104c3 in order from the outer side of the inner container 104. Examples of raw materials constituting the inner container 104 include unmodified polyolefin, acid-modified polyolefin, EVOH, and the like. Examples of polyolefins include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymers, and mixtures thereof.

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 thermal energy of the molten resin may soften and deform the inner container 104 during injection molding of the outer jacket 105, 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 thermal energy of the molten resin. At this time, the outermost resin absorbs heat energy, so that the heat energy transferred to the inner container 104 is reduced, so that the deformation of the inner container 104 caused by injection molding can be suppressed. In addition, since the outermost layer 104c1 is easily melted, the adhesion between the outermost layer 104c1 and the outermost layer 104c1 can be improved, so that the outer peripheral surface of the inner container 104 and the outermost outer layer 105 can be prevented from peeling off due to impact such as dropping. In addition, in this specification, the "melting point" refers to the melting peak temperature Tpm measured in accordance with JIS K7121:2012.

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 higher, more preferably 10°C or higher, and even more preferably 20°C or higher. This is because the effects of suppressing deformation and improving adhesion are significant in this case. The difference in melting point is, for example, 5 to 50°C, specifically, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50°C, or it can be between any two values shown here Range.

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

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

The outermost layer resin preferably contains polyolefin. The polyolefin may be an unmodified polyolefin or a modified polyolefin (for example, acid-modified polyolefin).

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 so that the operability of the inner container 104 may deteriorate. As the unmodified polyolefin, polyethylene is preferable, and one or both of LDPE and LLDPE is more preferable. This is because the melting point of the outermost layer resin tends to be low in this case.

The outermost layer resin may also include acid-modified polyolefin and unmodified polyolefin. The acid-modified polyolefin has excellent adhesion, so by containing acid-modified polyolefin and unmodified polyolefin in the outermost resin, it is possible to increase the adhesion between the outer casing 105 and the inner container 104 while suppressing excessive stickiness. Accessibility. The content of the acid-modified polyolefin in the outermost layer resin is, for example, 5 to 95% by mass, and preferably 30 to 70% by mass. The content may specifically be 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95% by mass, or may be a range between any two numerical values shown here.

The adjacent layer 104c2 is a layer adjacent to the outermost layer 104c1. The adjacent layer resin constituting the adjacent layer 104c2 may be any resin whose melting point is higher than that of the outermost layer resin. For example, when the outermost layer resin is LDPE, HDPE or PP having a higher melting point than LDPE can be used as the adjacent layer resin. In addition, as the adjacent layer resin, it is also possible to use a recycled resin obtained by recovering flash generated in the previous production process and reusing it. When the melting point of the resin forming any layer constituting the inner container 104 is higher than the melting point of the outermost layer 104c1, the melting point of the recycled resin is generally higher than the melting point of the outermost layer resin.

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 and 70% can also be the range between any two numerical values shown here.

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 resin excellent in heat resistance and rigidity, and may be made of, for example, polypropylene resin. The other layer 104c3 can be omitted when not needed. The wall thickness of the adjacent layer 104c2 is preferably 20% or more with respect to the wall thickness of the inner container 104. In this case, the other layer 104c3 can easily improve the heat resistance or rigidity of the inner container 104. Relative to the wall thickness of the inner container 104, the wall thickness of the adjacent layer 104c2 is, for example, 0 to 70%, specifically, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 , 65, 70%, can also be the range between any two numerical values shown here.

The inner container 104 is, for example, five types of six-layer multi-layer containers, and the specific layer structure thereof is shown in the following manner, for example. The adhesive layer is a layer made of adhesive resin such as acid-modified polypropylene. [Table 1]

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. Because the melting point of the resin constituting the other layer 104c3 is higher than the melting point of the outermost resin, the melting point of the recycled resin will also become higher than that of the outermost resin. The melting point is high. [Table 2]

＜Jacket 105＞ As shown in FIGS. 2 to 3, the outer casing 105 is integrally molded so as 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 jacket 105 includes a cylindrical portion 105a and a bottom portion 105b. The cylindrical portion 105a and the bottom 105b cover the outer peripheral surface 104a and the bottom surface 104b, respectively. The jacket 105 covers at least the receiving portion 107, and the mouth portion 108 may or may not be covered.

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

The container body 102 can be manufactured by using a method including an integral molding step of integrally molding the inner container 104 and the outer jacket 105. As shown in Figures 7 to 8, in the integral molding step, the mouth 108 is fixed to the fixing portion 110 having the opening 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 state in the mold 109 for injection molding, the support rod 111 is inserted into the inner container 104, and the support rod 111 is pressed against the inner surface of the bottom surface 104b. Thereby, it is possible to suppress the occurrence of displacement of the receiving portion 107 of the inner container 104 during injection molding.

In this state, the space outside the inner container 104 in the cavity 109 a of the mold 109 is filled with resin to form the outer jacket 105. At this time, it is preferable to pressurize the inside of the inner container 104 so as not to deform the inner container 104 due to resin pressure. Pressurization can be performed by blowing in water or air. The resin is filled into the cavity 109a from the gate 109b. The shutter 109b is preferably arranged at a position opposed to the bottom surface 104b (preferably the pinch-off portion 107c) of the inner container 104. This is because in this case, it is easy to uniformly fill the resin in the whole surrounding the inner container 104.

The resin for injection molding 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 resin for injection molding 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 it may be a range between any two numerical values shown here.

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

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

2. The second embodiment Next, the second embodiment of the present invention will be described. This embodiment is similar to the first embodiment. The inner container 104 has an outer shell 113 and an inner bag 114 as shown in Figs. The difference point. The following description will focus on this difference.

In the present embodiment, the laminated peelable container separates the inner bag 114 from the outer shell 113 as the content decreases, so that the inner bag 114 separates and shrinks from the outer shell 113. In this container, since external air does not easily enter the inner bag 114, it is possible to suppress deterioration of the contents.

As shown in FIG. 11, the housing 113 is comprised by, for example, the outermost layer 113c1, the adjacent layer 113c2, and the other layer 113c3. The inner bag 114 has, for example, an outermost layer 114c1, an adhesive layer 114c2, and an inner surface layer 114c3. The outermost layer 113c1 and the adjacent layer 113c2 correspond to the outermost layer 104c1 and the adjacent layer 104c2 according to the first embodiment, and their configuration and effects are the same as those of the first embodiment.

The other layer 113c3, the outermost layer 114c1, the adhesive layer 114c2, and the inner surface layer 114c3 correspond to the other layer 104c3 of the first embodiment. The other layer 113c3 and the inner surface layer 114c3 may 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 excellent in peelability from the other layers 113c3, and is preferably composed of ethylene-vinyl alcohol copolymer (EVOH) resin or the like. The adhesive layer 114c2 is preferably composed of an adhesive resin such as acid-modified polyolefin.

As shown in Figure 12, the pinch-off portions 107c block the bottoms of the outer shell 113 and the inner bag 114, respectively. However, since the pinch-off portions 107c on the outer shell 113 are particularly weak, the outer shell 113 can be opened by applying an impact to the outer shell 113. The pinch-off portion 107c thus forms the outside air introduction portion 115. It is also possible to introduce external air between the outer case 113 and the inner bag 114 through the external air introduction part 115. The external air introduction part 115 may be formed by perforating the housing 113. The external air introduction part 115 may be provided in the accommodating part 107 or the mouth part 108.

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

When the jacket 105 does not cover the mouth 108, if the outside air introduction part 115 is provided on the mouth 108, the vent 105c is not necessary.

When forming the vent 105c during injection molding, for example, a needle pin can be first arranged at a location corresponding to the vent 105c, and then when the container body 102 is removed from the mold 109, the needle pin can be pulled out from the outer jacket 105.

The inner container 104 is preferably peeled off the inner bag 114 in advance before the integral forming step. This is because it is easy to pre-peel before the outer jacket 105 is integrally formed in the inner container 104.

＜Pump 112＞ The pump 112 is configured to discharge the contents from the inner container 104. When the inner container 104 is a laminated peeling container, it is preferable that the pump 112 is configured so as not to introduce external air into the inner container 104.

As shown in FIG. 13, the pump 112 includes a main body 112a, a piston 112b, a nozzle 112c, and a tube 112d. The main body portion 112a includes a cylindrical portion 112a1, a cylinder portion 112a2, and an upper wall portion 112a3. An engaging portion (internal thread portion) (not shown) that engages with the engaging portion (external thread portion) 108a is provided on the inner surface of the cylindrical portion 112a1. The cylinder 112a2 is inserted into the mouth 108. The outer diameter of the cylinder 112a2 and the inner diameter of the mouth 108 are substantially the same. The cylinder portion 112a2 is cylindrical, and the piston portion 112b is slidable in the cylinder portion 112a2. The internal space of the cylinder 112a2 communicates with the nozzle 112c and the pipe 112d. A valve mechanism composed of an elastic member and a valve is contained in the internal space of the cylinder 112a2. By sliding the piston portion 112b to operate the valve mechanism, the sucked content can be discharged from the nozzle 112c through the tube 112d.

3. The third embodiment The third embodiment of the present invention will be described with reference to FIG. 14. This embodiment is similar to the second embodiment, and its main difference is that the external air introduction part 115 is provided at the mouth 108 of the inner container 104. Next, the description will focus on the distinguishing features.

When the housing 113 is sealed, the outside air introduction part 115 is not provided in the pinch-off part 107c, and it is preferable to provide a through hole in the housing 113 to constitute the outside air introduction part 115. In this case, the external air introduction part 115 is preferably provided at a location where the inner container 104 is not covered by the outer jacket 105. In this case, the vent 105c may not be provided on the jacket 105.

As shown in FIG. 14, the external air introduction part 115 is preferably provided at the mouth 108, and particularly preferably provided at a position covered by the cylindrical part 112a1 of the pump 112 shown in FIG. 12. In this case, in the state where the pump 112 is installed, the outside air introduction part 115 is invisible, so the appearance is beautiful. The external air introduction part 115 may ventilate to the outside through a gas passage such as a gap between the piston part 112b and the cylindrical part 112a1, or a gap between the lower end of the cylindrical part 112a1 and the inner container 104.

It is preferable that the external air introduction part 115 is provided in the flat part 108b provided in the mouth part 108. As shown in FIG. In this case, it is easy to form the external air introduction part 115 using a punch tool such as a drill. The flat portion 108b may be provided at a position closer to the accommodating portion 107 than the engaging portion 108a, or may be provided as a divided engaging portion 108a. In the latter case, there is an advantage that there is no need to extend the mouth portion 108 in order to provide the flat portion 108b.

(2nd point of view) 1. The first embodiment of the second viewpoint In this section, the structure of the double container 1 according to the first embodiment will be described. FIG. 15 shows a perspective view of the double-layer container 1 according to the first embodiment. FIG. 16 shows the state in which the cover 30 is removed from the state in FIG. 15. Fig. 17 shows a front view and a back view of the double container 1 according to the first embodiment. FIG. 18 shows the state in which the cover 30 is removed from the state in FIG. 17. FIG. 19 shows a left side view and a right side view of the double-layer container 1 according to the first embodiment. FIG. 20 shows the state in which the cover 30 is removed from the state in FIG. 19. FIG. 21 shows a top view and a bottom view of the double-layer container 1 according to the first embodiment. FIG. 22 shows the state in which the cover 30 is removed from the state in FIG. 21.

1.1 Subject 2 The double-layer container 1 is a so-called laminated peeling container. As shown in FIGS. 15-22, the double-layer container 1 is equipped with the main body 2 (the outer shell 21 and the inner bag 22) and the external air introduction hole 52. As shown in FIG. The housing 21 can be pressed from the outside. It is configured to flow out the content contained in the inner bag 22 (accommodating space 26) from the mouth 3 by pressing. The inner bag 22 is configured to be compressed by the air introduced into the intermediate space 25 through the external air introduction hole 52 after the content is reduced.

The outer shell 21 and the inner bag 22 are blow-molded by a multi-layer parison, and are formed in an integrally formed state. The use state is to peel the inner bag 22 from the outer shell 21 before use, and then fill the contents until the inner bag 22 and the inner bag 22 The housing 21 is in contact. 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 from the outer shell 21 as the contents are discharged.

The main body 2 is provided with the outer shell 21 and the inner bag 22 as described above, and the wall thickness of the outer shell 21 is made thicker than the inner bag 22 to improve the shape recovery.

The housing 21 is composed of, for example, low-density polyethylene, linear low-density polyethylene, polyethylene, polypropylene, ethylene-propylene copolymer, and mixtures thereof, and the like. The outer shell 21 has a single-layer or multi-layer structure, and it is preferable that at least one of the innermost layer and the outermost layer contains a lubricant. When the outer shell 21 has a single-layer structure, the single layer is the innermost layer and the outermost layer, and the lubricant may be contained in this layer. When the outer shell 21 has a two-layer structure, the layer on the inner surface side of the container is the innermost layer, and the layer on the outer surface of the container is the outermost layer, and at least one of them may contain a lubricant. When the outer shell 21 is configured in 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.

The innermost layer of the outer shell 21 is a layer in contact with the inner bag 22, and by containing 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 housing 21 is a layer that is in contact with the mold during blow molding. By containing a lubricant in the outermost layer of the housing 21, mold release properties can be improved.

One or both of the innermost layer and the outermost layer of the outer shell 21 may be formed of a random copolymer between propylene and other monomers. Thereby, the shape restoration property, transparency, and heat resistance of the housing 21 as the housing can be improved.

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

The tensile modulus of elasticity of the random copolymer is preferably 400 to 1600 MPa, more preferably 1000 to 1600 MPa. When the tensile elastic modulus is in this range, the shape recovery performance is particularly good.

When the container is too rigid, the feeling of use of the container becomes poor. Therefore, 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 preferable that the material mixed with the random copolymer is less than 50% by weight with respect to the entire mixture so as not to significantly impair the effective performance of the random copolymer. For example, a random copolymer and linear low-density polyethylene may be mixed in a weight ratio of 85:15 to form the shell 21.

The inner bag 22 includes an EVOH layer provided on the outer surface of the container, an inner surface layer provided on the inner surface of the EVOH layer container, and an adhesive layer provided between the EVOH layer and the inner surface layer. By providing the EVOH layer, gas barrier properties and peelability from the housing 21 can be improved.

The EVOH layer is a layer composed of ethylene-vinyl alcohol copolymer (EVOH) resin, which can be prepared by hydrolysis of a copolymer of ethylene and ethyl acetate. The ethylene content of the EVOH resin is, for example, 25 to 50 mol%, and from the viewpoint of oxygen barrier properties, it is preferably 32 mol% or less. The lower limit ratio of the ethylene content is particularly limited. The lower the ethylene content, the easier the flexibility of the EVOH layer is to decrease, so it is preferably 25 mol% or more. In addition, the EVOH layer preferably contains an oxygen absorber. When passing, the EVOH layer contains an oxygen absorber, which can further improve the oxygen barrier properties of the EVOH layer.

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 housing 21 by using a heating type hole-opening 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 in the housing 21, To prevent the hole from reaching the inner bag 22. From this viewpoint, it is preferable that the difference between (melting point of EVOH)-(melting point of random copolymer layer) is large, and it is preferably 15°C or higher, particularly preferably 30°C or higher. The difference in the melting point is, for example, 5 to 50°C.

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

The adhesive layer is a layer that has the function of adhering the EVOH layer to the inner surface layer. Ethylene), and ethylene ethyl acetate copolymer (EVA). An example of an adhesive layer is low-density polyethylene or a mixture of linear low-density polyethylene and acid-modified polyethylene.

In addition, it should be noted that the main body 2 has a flat shape as a whole. This configuration can have the advantageous effect of being easy for the user to press and the content can be easily squeezed out.

1.2 Check valve 6 Hereinafter, the external air introduction hole 52 and the check valve 6 will be described. FIG. 23 is a diagram showing an end surface constituting the internal structure of the double-layer container 1 according to the first embodiment. The area surrounded by dotted lines in Figure 23 has design features. FIG. 24 shows the detailed structure of the check valve 6.

As shown in FIG. 23, the outside air introduction hole 52 is provided in a specific area 51 on the bottom side of the housing 21. Here, the bottom side refers to the side away from the mouth 3 when the double-layer container 1 is halved 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.

The external air introduction hole 52 is configured to fit the check valve 6. The check valve 6 may be a ball valve, for example. The check valve 6 can introduce air into the intermediate space 25 inside the casing 21 and outside the inner bag 22 after the content flows out, so that the shape of the casing 21 can be restored to its original shape. In other words, the intermediate space 25 and the external space communicate with each other through the external air introduction hole 52.

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

Next, the check valve 6 fitted in the external air introduction hole 52 will be described. As shown in FIGS. 24A to 24G, the check valve 6 is a ball valve composed of a cylinder 60 and a ball 69. The cylinder 60 has a hollow portion 6 s provided to communicate the external space and the intermediate space 25. The ball 69 is movably housed in the cavity 6s 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 move freely in a specific direction (here, the vertical direction of the paper).

The cylindrical body 60 has a shaft portion 61 arranged in the outside air introduction hole 52, a locking portion 62 provided on the outer space side of the shaft portion 61 and preventing the cylindrical body 60 from being inserted into the intermediate space 25, and an intermediate space provided on the shaft portion 61 The enlarged diameter portion 63 on the 25 side and prevents the cylindrical body 60 from being pulled out from the outside of the main body 2. The shaft portion 61 is configured to have a tapered shape (taper shape) toward the intermediate space 25 side. The outer peripheral surface of the shaft portion 61 is in close contact with the edge of the outside air introduction hole 52, so that the cylinder 60 is mounted on the main body 2.

The surface 66 surrounding the hollow portion 6s is provided with a stopper 65 for engaging the ball 69 when the ball 69 moves from the intermediate space 25 side to the outer space side. The stopper 65 is composed of a ring-shaped protrusion, and when the ball 69 comes into contact with the stopper 65, the flow of air passing through the cavity 6s is blocked.

The front end of the cylindrical body 60 is a flat surface 641. The flat surface 641 is provided with an opening 64 communicating with the hollow portion 6 s, and has a plurality of slit portions 642 extending radially from the opening 64.

As shown in FIG. 24F, when the check valve 6 is inserted into the outside air introduction hole 52 from the enlarged diameter portion 63 side, and the locking portion 62 is pressed at a position in contact with the outer surface of the housing 21, the outer circumference of the shaft portion 61 In a state where the surface is in close contact with the edge of the external air introduction hole 52, the check valve 6 supports the housing 21. When the housing 21 is compressed in a state where the air enters the intermediate space 25, the air in the intermediate space 25 enters the cavity 6 s through the opening 64, and pushes the ball 69 upward to abut against the stopper 65. When the ball 69 comes into contact with the stopper 65, the flow of air passing through the cavity 6s is blocked.

When the outer casing 21 is further compressed in this state, the pressure in the intermediate space 25 becomes higher, and as a result, the inner bag 22 is compressed, and the contents are discharged from the storage space 26 in the inner bag 22. When the compression force on the housing 21 is released, the housing 21 will return to its original shape by virtue of its own elasticity. As shown in FIG. 24G, as the housing 21 returns to its original shape and the pressure in the intermediate space 25 is reduced, a force F toward the inside of the container is applied to the ball 69. As a result, the ball 69 moves toward the bottom surface of the hollow portion 6s to form a state as shown in FIG. 24F, and external air (air) is introduced into the intermediate space 25 through the gap between the ball 69 and the surface 66 and the opening 64.

It should be noted that the check valve 6 is a ball valve as described above, which is only an example, and the present invention is not limited to this. Any structure may be used as long as it is a structure that can introduce external air into the intermediate space 25 and can prevent backflow.

1.3 Mouth 3 and lid 30 In the main body 2, the mouth 3 is configured to be able to attach a cover 30 as a cover member. A male screw part is provided in the mouth part 3, and a cap 30 having an female screw is attached to the male screw part. The cover 30 is configured with its top surface 31 as a grounding surface, and can be placed upside down. Of course, the bottom surface 23 of the double-layer container 1 may be placed upright as a mounting surface. In order to be able to stand upside down stably, in the double-layered container 1, assuming that the area of the top surface 31 of the lid 30 is S1 and the area of the mouth 3 is S2, the following conditions are preferably satisfied: S1≧1.5×S2.

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, also It can be a range between any two values shown here. Since it can be placed in an upside-down state, the residual rate can be suppressed even when sticky substances such as jam, mayonnaise, or ketchup are used as storage items.

Referring again to FIG. 23, the specific area 51 is configured to have an inclination angle with respect to the opening surface 53 defining the recess 5. When the angle of inclination is θ, in the double-layer container 1, the angle of inclination θ may 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, it can also be shown here The range between any two values.

With such an inclination angle θ, external air can be introduced into the intermediate space 25 from above to below more smoothly. That is, this configuration helps to effectively peel the inner bag 22 from the outer shell 21.

The wall 54 defining the recess 5 is configured not to be perpendicular to the opening surface 53. Assuming that the included angle is φ, the angle φ in the double-layer container 1 can be 5 degrees or more and 75 degrees or less. 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 The degree can also be a range between any two numerical values shown here. In addition, it is preferable to satisfy: φ≧θ.

With such an angle φ, when the inner bag 22 is peeled from the outer shell 21, it is possible to prevent the inner bag 22 from being caught in the recess 5 (convex when viewed from the inner bag 22 side). That is, this configuration helps to effectively peel the inner bag 22 from the outer shell 21.

The double-layer container 1 further includes a groove 55. Specifically, the groove portion 55 is provided on the housing 21 at a position closer to the bottom side than the specific area 51. By providing such a groove portion 55, when the external air introduction hole 52 is drilled with a drill in the license step, a fixing jig (not shown) that can be accommodated in the groove portion 55 and has a convex portion is used as a positioning reference. However, the depth of the groove 55 is preferably shallower than the depth of the recess 5. When a shrink film made of marked contents is stuck on the outer side of the double-layer container 1, the dents are not obvious, so the appearance is beautiful.

2. The second embodiment related to the second viewpoint In this section, the double-layer container 1 according to the second embodiment will be described. FIG. 25 shows a perspective view of the double-layer container 1 according to the second embodiment. Fig. 26 shows the state in which the cover 30 is removed from the state in Fig. 25. FIG. 27 shows a front view and a back view of the double-layer container 1 according to the second embodiment. FIG. 28 shows the state after the cover 30 is removed from the state in FIG. 27. FIG. 29 shows a left side view and a right side view of the double-layer container 1 according to the second embodiment. FIG. 30 shows the state in which the cover 30 is removed from the state in FIG. 29. FIG. 31 shows a top view and a bottom view of the double-layer container 1 according to the second embodiment. Fig. 32 shows the state after the cover 30 is removed from the state of Fig. 31. FIG. 33 is an end view showing the internal structure of the double-layer container 1 according to the second embodiment. It should be noted that the area surrounded by dotted lines in FIG. 33 has design features.

The double-layer container 1 according to the second embodiment has the same structure as the basic structure of the double-layer container 1 according to the first embodiment. As shown in FIGS. 25 to 33, the difference lies in the shape of the main body 2. The bottom surface 23 (above the paper surface) of the double-layered container 1 in the second embodiment has a circular shape, and cannot stand when the bottom surface 23 is used as a mounting surface. Therefore, the second embodiment is configured on the premise that the top surface 31 of the cover 30 serves as the mounting surface.

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

In the second embodiment, by providing the outside air introduction hole 52 in the specific area 51 on the bottom side of the housing 21, after taking out the contents, the outside air will be introduced from above to the intermediate space 25 through the outside air introduction hole 52 immediately. Inside. That is, compared with the prior art, the inner bag 22 can be peeled off from the outer shell 21 more effectively.

3. Conclusion 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 portion 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 upside down. In the double-layer container, the area of the top surface of the lid is S1, and the area of the mouth is 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 casing. In the double-layer container, the specific area is located in a recess of the housing and is configured to have an inclination angle with respect to an opening surface that defines the recess. In the double-layer container, the inclination angle is 5 degrees or more and 45 degrees or less. In the double-layer container, the wall defining the recess is configured not to be perpendicular to the opening surface. In the double-layered container, a groove portion is further provided, and the groove portion is provided closer to the bottom side than the specific area of the casing. In the double-layered container, the depth of the groove portion is shallower than the depth of the concave portion. In the double-layer container, the check valve is a ball valve. Of course, the present invention is not limited to this.

(3rd viewpoint) 1. The first embodiment of the third viewpoint As shown in FIG. 34, the double container 201 according to the first embodiment of the present invention includes a container body 202. As shown in FIG. 36A, the container body 202 has an outer shell 203 and an inner bag 204, and the inner bag 204 shrinks as the content decreases.

As shown in FIG. 34, the container main body 202 includes a mouth portion 205, a body portion 206, and a bottom portion 207. The mouth portion 205 includes an engaging portion 205a to which a pump (not shown) can be attached. The engaging portion 205a is an external thread portion in the case of a screw type pump, and is an annular protrusion protruding in the circumferential direction in the case of a push type pump. The mouth portion 205 is provided to extend from the upper end portion 206 a of the body portion 206. The mouth 205 is cylindrical. The outer diameter of the body portion 206 is larger than that of the mouth portion 205 (in this specification, when the cross section is not circular, the so-called "outer diameter" refers to the diameter of the circumscribed circle).

The body part 206 is cylindrical, and the bottom part 207 is provided at the lower end of the body part 206, and the lower end of the body part 206 is closed. The bottom portion 207 includes a central recess 207a provided in the center of the bottom 207 and a peripheral edge portion 207b surrounding the central recess 207a.

As shown in FIG. 35A, a locking portion 207a1, an external air introduction hole 207a2, an annular convex portion 207a3, and a positioning concave portion 207a4 are provided in the central concave portion 207a. As shown in FIG. 36A, the locking portion 207a1 is configured such that the locking protrusion 204a provided in the inner bag 204 is inserted into the insertion hole 203a provided in the housing 203. The locking portion 207a1 prevents the inner bag 204 from being detached from the outer shell 203. The external air introduction hole 207a2 is a through hole that penetrates the housing 203. As the inner bag 204 contracts, external air can be introduced into the intermediate space between the housing 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 recesses 207a4 are used to position the container body 202 in the circumferential direction when the container body 202 performs steps such as printing.

The peripheral edge portion 207b is provided with a ground portion 207b1 and a peripheral edge recessed portion 207b2. The grounding portion 207b1 is a portion that comes into contact with the mounting surface on which the container body 202 is placed when the container body 202 is allowed to stand. If the entire peripheral portion 207b is used as the ground portion 207b1, when the container body 202 is made to stand, the central recess 207a forms a sealed space between the container body 202 and the mounting surface, which may cause external air to be introduced through the external air introduction hole 207a2 Obstructed situation. Therefore, the peripheral recess 207b2 is provided as a gas passage to prevent the formation of a closed space in the central recess 207a.

When the contents in 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, the outside air can be introduced into the space between the inner bag 204 and the housing 203 through the outside air introduction hole 207a2. As shown in FIG. 36A, since the radius of curvature of the peripheral edge portion 207b is small, the inner bag 204 is not easily separated from the housing 203 at the peripheral edge portion 207b, and it is difficult to form a gas passage through which the external air introduced from the external air introduction hole 207a2 flows. Therefore, it is not easy to introduce external air into the body portion 206. In this case, the outer shell 203 and the inner bag 204 shrink together as the content decreases. In this embodiment, a spacer 209 is arranged between the outer shell 203 and the inner bag 204. In this embodiment, as the spacer member 209, a protrusion 203b protruding from the outer case 203 to the inner bag 204 is provided. When the spacer 209 is installed, a gap 208 is formed between the outer shell 203 and the inner bag 204 adjacent to the spacer 209. The gap 208 can form a gas passage connecting the body part 206 and the bottom 207, which is introduced from the outside air introduction hole 207a2 The outside air of φ is easily introduced to the body portion 206 through the peripheral edge portion 207b. The spacer 209 is arranged to radiately span the bottom 207 and the body 206, and this structure is easy to form a gas passage across the bottom 207 and the body 206.

As shown in Figures 37 to 39, the container body 202 can cover the inner preform 214 constituting the inner bag 204 with the outer preform 213 constituting the outer preform 203, and the inner preform 214 and the outer preform 214 213 is heated and formed by biaxial stretch blow molding.

As shown in FIG. 37, the inner preform 214 has a bottomed cylindrical shape, and has a mouth portion 214a, a body portion 214b, and a bottom portion 214c. A flange 214a1 is provided at the open end of the mouth 214a. A positioning pin 214c1 is provided on the bottom 214c.

As shown in FIG. 37, the outer preform 213 has a bottomed cylindrical shape, and includes a mouth portion 213a, a body portion 213b, and a bottom portion 213c. As shown in FIG. 38, the inner surface of the bottom part 213c of the outer preform 213 is provided with protrusions 213c1 arranged in a radial shape. A positioning hole 213c2 and an external air introduction hole 213c3 are provided in the bottom 213c. As shown in FIG. 39B, an annular convex portion 213c4 is provided on the outer surface of the bottom portion 213c. The positioning hole 213c2 and the external air introduction hole 213c3 are arranged in a region inside the annular convex portion 213c4. The outer preform 213 is made into a size that can be inserted into the inner preform 214.

The inner preform 214 and the outer preform 213 can be formed by blow molding or injection molding of thermoplastic resins such as polyester (for example: PET) and polyolefin (for example: polypropylene, polyethylene). In one example, the inner preform 214 may be formed by blow molding of polypropylene, and the outer preform 213 may 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 fusion to each other during blow molding. In addition, when the outer preform 213 is formed by injection molding, the outside air introduction hole 213c3 can be formed during the injection molding, so that the time spent in post-processing can be saved.

2. Biaxial stretch blow molding The biaxial stretch blow molding can be performed by the following method.

First, as shown in FIG. 39, 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 is in contact with the opening end of the mouth 213a, and the positioning pin 214c1 is inserted into the positioning hole 213c2. Thereby, the inner preform 214 and the outer preform 213 are positioned with each other. In this state, the mouth portion 214a and the mouth portion 213a are opposed to each other, and the body portion 214b and the body portion 213b are opposed to each other.

Then, the softening assembly 215 is heated.

Subsequently, the assembly 215 is placed in a mold for blow molding, and air is blown into the inner preform 214 while the mouth portion 213a and the annular convex portion 213c4 are supported by a jig, so that the assembly 215 expands and interacts with the mold. The inner surface of the cavity fits tightly. At this time, by pressing a support rod (not shown) against the inner bottom surface of the inner preform 214, it is possible to prevent the assembly 215 from shaking in the mold. In addition, the inner bottom surface of the inner preform 214 may be provided with a recess for engaging the support rod, so that the support rod can be easily fixed in the inner preform 214.

By blow molding, the assembly 215 expands to reach the container body 202 shown in FIGS. 34 to 36. The mouth parts 213a and 214a become the mouth part 205, the body parts 213b and 214b become the body part 206, and the bottom parts 213c and 214c become the bottom part 207. The protrusion 213c1, the annular convex portion 213c4, and the outside air introduction hole 213c3 become the protrusion 203b, the annular convex portion 207a3, and the outside air introduction hole 207a2, respectively. During the blow molding, the mouth portions 213a, 214a, the annular convex portion 213c4, and the area inside thereof are hardly deformed, and the other parts are mainly deformed. The external air introduction hole 213c3 is arranged in the inner region of the annular convex portion 213c4, and therefore it can be prevented from being blocked due to deformation during blow molding. The flange 214a1 constitutes a flange 204b covering the opening end of the mouth 205 of the container body 202 as shown in FIG. 34A.

After the blow molding, the positioning hole 213c2 becomes the insertion hole 203a as shown in FIG. 36A, and the positioning pin 214c1 is inserted into the insertion hole 203a. Subsequently, the positioning pin 214c1 is deformed (ie, squashed or bent) to form a locking protrusion 204a as shown in FIG. 36A. Thus, the locking portion 207a1 of the container body 202 is formed.

3. Details of biaxial stretch blow molding In the above-mentioned biaxial stretch blow molding, the mold unit 220 shown in FIGS. 40 to 42 can be used for example. The mold unit 220 includes a mouth support mold 221, a bottom support mold 222, and forming molds 223 and 224.

The mouth support mold 221 is configured to support the mouth 213 a of the outer preform 213. An insertion hole 221a is provided in the mouth support mold 221, and the support rod 225 is inserted into the insertion hole 221a. The support rod 225 can be extended and contracted by a driving mechanism (not shown). The bottom support mold 222 is configured to be driven by a driving mechanism 222c and movable in the longitudinal extension direction (up and down direction in FIG. 40). The forming dies 223 and 224 can be opened and closed, and respectively have cavity surfaces 223a and 224a. 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.

The method includes a preform heating step, a bottom support step, an extension step, and a blow molding step.

＜Preform heating step＞ In the preform heating step, the assembly 215 composed of the inward preform 214 covering the outer preform 213 is mounted on the mouth support mold 221 as shown in FIG. 40, and heated in this state. The component 215 softens it. The heating of the assembly 215 may be performed in a state where the assembly 215 is arranged between the forming dies 223 and 224, or may be performed outside the space between the forming dies 223 and 224. In addition, before the preform heating step, the front end of the support rod 225 may also abut the inner bottom surface of the inner preform 214. This can prevent the softened assembly 215 from shaking.

＜Bottom support step＞ In the bottom support step, as shown in FIG. 41, the bottom support mold 222 is moved toward the bottom 213c of the outer preform 213, and the bottom support mold 222 is used to support the bottom 213c of the outer preform 213. The bottom support mold 222 is provided with a concave portion 222a capable of accommodating the annular convex portion 213c4, and the bottom support mold 222 preferably supports the bottom portion 213c such that the annular convex portion 213c4 is contained in the concave portion 222a. As a result, it is possible to prevent the annular convex portion 213c4 and the inner region from being extended during the blow molding step. The recess 222a is preferably ring-shaped. The bottom support mold 222 is provided with a recess 222b capable of accommodating the positioning pin 214c1, and preferably supports the bottom 213c so as to accommodate the positioning pin 214c1 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 shows the state where the forming molds 223 and 224 are closed, the forming molds 223 and 224 only need to be closed at any point before the blow molding step, and may be closed after the longitudinal stretching step.

＜Vertical extension step＞ In the longitudinal extension step, as shown in Figure 41 to Figure 42, the component 215 can be extended in the longitudinal direction (up and down direction in Figure 42) by extending the inner bottom surface of the preform 214 in the top of the support rod 225 extend. At this time, it is preferable to retreat the bottom support mold 222 in synchronization with the extension of the support rod 225. As a result, the assembly 215 can be stabilized and extended. It should be noted that the longitudinal extension step may be performed without using the bottom support mold 222 to support the bottom portion 213c, or the bottom support step may be performed after the longitudinal extension step.

＜Blow molding steps＞ In the blow molding step, the assembly 215 can be extended laterally (even if it expands) by blowing air into the inner preform 214 in the state shown in FIG. 42 and give the cavity surfaces 223a, 224a the shape . The air can be blown in through the gas passage 226 between the mouth support mold 221 and the support rod 225, or it can be performed by providing a gas passage in the support rod 225 and blowing air from the side of the support rod 225 .

In this embodiment, the bottom 213c of the outer preform 213 is blown with air while being supported by the bottom support mold 222, so that the bottom 213c of the outer preform 213 can be suppressed from extending.

It should be noted that the blow molding step can be performed simultaneously with the longitudinal stretching step. In other words, it is possible to blow air into the inner preform 214 while extending the component 215 longitudinally. In addition, the longitudinal extension step can also be omitted, and the component 215 is not longitudinally extended after the bottom support step, and only air is blown in.

4. Other implementation methods ･In the above-mentioned embodiment, the spacer member 209 is provided in a radial shape, but the spacer member 209 may have other shapes. For example, the spacing member 209 may be configured as a non-continuous circle. In this case, a gas passage is formed at the position of the gap in the circle. The discontinuous circle is preferably a plurality of discontinuous circles arranged in a concentric shape. As shown in FIG. 43, such a spacer member 209 can be formed by using an outer preform 213 having a non-continuous round protrusion 213c1. ･In the above embodiment, the outer preform 213 is provided with the protrusion 213c1 to form the protrusion 203b protruding from the outer case 203 to the inner bag 204. However, as shown in FIGS. 44 to 45, the inner preform 214 may also be The bottom 214c is provided with protrusions 214c2 (for example, radial protrusions as shown in FIG. 44, or non-continuous circular protrusions as shown in FIG. 45) to form protrusions (spacers) protruding from the inner bag 204 to the outer shell 203. ･The spacer 209 may be composed of other components. The spacer 209 between the outer shell 203 and the inner bag 204 can be arranged by blow molding in a state where the spacer is arranged between the inner preform 214 and the outer preform 213.

5. Inventions from other viewpoints When the inner preform 214 is a blow-molded body (specifically, a direct blow-molded body), as shown in FIG. 46, the bottom portion 214g of the inner preform 214 blocks the position of the parison to form a cut portion 214h. Since the strength of the embryo-cut portion 214h is relatively weak, the embryo-cut portion 214h may be cracked when the vicinity of the embryo-cut portion 214h is stretched vigorously during the biaxial stretch blow molding.

In one example, as shown in FIG. 46, the inner preform 214 has a multilayer structure, and includes an innermost layer 214d, a gas barrier layer (for example, an EVOH layer) 14e, and an outermost layer 214f in order from the inside. The innermost layer 214d and the outermost layer 214f may be made of polyolefin (for example, polyethylene, polypropylene), PET, or the like. At the embryo-cut portion 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. In the biaxial stretch blow molding, when the part near the cut part 214h is stretched vigorously, the gas barrier layer 214e may be cracked or the gap G may become larger, which may cause problems such as poor gas barrier properties.

The above-mentioned problems are explained in "2. Biaxial stretch blow molding" and "3. Details of biaxial stretch blow molding". By suppressing the extension of the bottom 213c of the outer preform 213, the The expansion of the component 215 can be resolved. Since the cut 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 part 214h can also be suppressed, thereby solving the above-mentioned problem.

In "2. Biaxial Stretch Blow Molding", by providing the ring-shaped convex portion 213c4 on the bottom 213c of the outer preform 213, the rigidity of the bottom 213c can be increased and the extension of the bottom 213c can be suppressed. The structure provided to increase the rigidity of the bottom portion 213c may be a reinforcing structure other than the annular convex portion 213c4.

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 step is performed in this state to suppress the extension of the bottom 213c. In the above description, although the annular convex portion 213c4 is housed in the concave portion 222a, even if the annular convex portion 213c4 is not present in the bottom portion 213c, the bottom portion 213c can be supported by the bottom support mold 222. The friction between the 213c and the bottom support mold 222 suppresses the extension of the bottom 213c.

Considering the above content, according to the present invention, a method for manufacturing a double-layer container is provided, which includes a blow molding step. The blow molding step is to form the inner preform while the inner preform covers the outer preform. The preform and the outer preform are heated to soften, and air is blown into the inner preform in this state. The inner preform is a blow-molded body, and the blow-molding The step is performed while suppressing the extension of the bottom of the outer preform.

Preferably, the outer preform has a reinforcement structure that suppresses the extension of the bottom of the outer preform. Preferably, the reinforcing structure is an annular convex portion provided at the bottom of the outer preform. Preferably, the blow molding step is performed by supporting the bottom of the outer preform with a bottom support mold while suppressing the extension of the bottom.

In addition, in another point of view, a method for manufacturing a double-layer container is provided, which includes a blow molding step in which the inner preform is heated in a state where the inner preform covers the outer preform. The blank and the outer preform are completed by blowing air into the inner preform in a softened state, the inner preform is a blow-molded body, and the outer preform is at the bottom Has a ring-shaped convex portion.

In addition, in the invention from another viewpoint, the position of the external air introduction hole is not limited, and it may be provided in any of the mouth 205, the trunk 206, and the bottom 207 of the container main body 202. In addition, the spacer 209 for forming a gap between the outer shell 203 and the inner bag 204 is not necessary. [Example]

Hereinafter, examples related to the first viewpoint are shown.

1. Production of the container body 102 <Example 1> The inner container 104 having the structure shown in FIG. 12 was produced by direct blow molding and the layer structure shown in Table 3. The wall thickness at the center in the height direction of the accommodating portion 107 of the inner container 104 is 1500 μm. [table 3]

The layers in Table 3 are made of the following materials. LDPE/LLDPE layer: LDPE (melting point 110°C, manufactured by Asahi Kasei Corporation, model: F2206) and LLDPE (melting point 120°C, manufactured by Japan Polyethylene Company, model: NF325N) mixed resin with a mass ratio of 50:50 PP layer: Polypropylene (manufactured by Sumitomo Chemical Co., Model: FH3315) EVOH layer: EVOH (manufactured by Mitsubishi Chemical Corporation, model: SF7503B) Acid-modified PE/LDPE layer: a mixed resin with a mass ratio of acid-modified polyethylene (manufactured by Mitsubishi Chemical Corporation, model: L522) and LDPE (melting point 110°C, manufactured by Asahi Kasei Corporation, model: F2206) of 50:50 LDPE layer: LDPE (manufactured by Asahi Kasei Corporation, model: F2206)

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

<Example 2> As the outermost layer 113c1 of the housing 113, 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.

The LDPE/ADH layer is a mixed resin with a mass ratio of 50:50 between LDPE (melting point 110℃, manufactured by Asahi Kasei Corporation, model: F2206) and bonding resin (melting point 120℃, manufactured by Mitsubishi Chemical Corporation, model: L522). , The melting point of the mixed resin is 115°C.

<Comparative example 1> As the outermost layer 113c1 of the outer shell 113, the container main body 102 was produced using the same method as in Example 1, except that a PP layer was used instead of the LDPE/LLDPE layer.

The PP layer is made of polypropylene (manufactured by Sumitomo Chemical Co., model: FH3315), and has a melting point of 140°C.

2. Evaluation 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 are good. In contrast, the comparative example had poor deformability and adhesiveness.

[Table 4]

＜Deformability＞ Visually confirm whether the inner container 104 in the jacket 105 is deformed, and evaluate it according to the following criteria. ○: No deformation ×: Deformation

＜Adhesiveness＞ The container body 102 was cut in the longitudinal direction to confirm whether the inner container 104 can be peeled off from the outer jacket 105 by hand, and the evaluation was performed according to the following criteria. ○: It will not peel off even if it is pulled forcefully by hand △: It can be peeled off after pulling forcefully by hand ×: Can be easily peeled off by hand

1: Double-layer container 2: Main body 3: Mouth 5: Recessed part 6: Check valve 6s: Hole part 21: Outer shell 22: Inner bag 23: Bottom 25: Intermediate space 26: Containment space 30: Lid 31: Top 51 : Specific area 52: External air introduction hole 53: Opening surface 54: Wall 55: Groove 60: Cylinder 61: Shaft 62: Locking part 63: Diameter expansion part 64: Opening part 65: Stopper part 66: Surface 69: Ball 101: Containment container 102: Container body 103: Cap opening member 104: Inner container 104a: Outer peripheral surface 104b: Bottom surface 104c1: Outermost layer 104c2: Adjacent layer 104c3: Other layer 105: Outer jacket 105a: Cylinder 105b: Bottom 105c: Vent part 107: Receiving part 107a: Carcass part 107b: Bottom part 107c: Pinch-off part 108: Mouth part 108a: Engagement part 108b: Flat part 109: Mold 109a: Cavity 109b: Gate 110: Fixed part 110a: Opening part 111: Support rod 112: Pump 112a: Body part 112a1: Cylinder part 112a2: Cylinder part 112a3: Upper wall part 112b: Piston part 112c: Nozzle 112d: Tube 113: Shell 113c1: Outermost layer 113c2: Adjacent layer 113c3: Other layer 114 : Inner bag 114c1: Outermost layer 114c2: Adhesive layer 114c3: Inner surface layer 115: Outside air introduction part 201: Double-layer container 202: Container body 203: Outer shell 203a: Insertion hole 203b: Protrusion 204: Inner bag 204a: Locking Protrusion 204b: Flange 205: Mouth 205a: Engagement part 206: Carcass 206a: Upper end 207: Bottom 207a: Central concave part 207a1: Locking part 207a2: Outside air introduction hole 207a3: Ring-shaped convex part 207a4: Positioning concave part 207b: Perimeter part 207b1: Landing part 207b2: Perimeter recess 208: Gap 209: Spacer 213: Outer preform 213a: Mouth 213b: Carcass 213c: Bottom 213c1: Protrusion 213c2: Positioning hole 213c3: Outside air introduction hole 213c4 : Ring-shaped convex part 214: Inner preform 214a: Mouth 214a1: Flange 214b: Carcass 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: cutting part 215: assembly 220: mold unit 221: mouth support mold 221a: insertion hole 222: bottom support mold 222a: recess 222b: recess 222c: drive mechanism 223: Forming die 223a: cavity surface 224: forming die 224a: cavity surface 225: support rod 226: gas passage 231: blank cut 641: flat surface 642: slit portion A: area B: area C: area F: force G: gap Tpm : Melting peak temperature θ: Inclination angle φ: Angle

104: inner container

104c1: outermost layer

104c2: Adjacent layer

104c3: other layers

105: coat

105a: tube

Claims (30)

A container containing: The main body of the container is integrally formed with the outer casing so as to cover the outer peripheral surface of the inner container, The jacket is an injection molded body, The inner container includes 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 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. 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. The storage container according to claim 1 or 2, wherein: The outermost layer resin contains unmodified polyolefin. The storage container according to claim 4, wherein: The outermost layer resin contains acid-modified polyolefin and the unmodified polyolefin. The storage container according to claim 1 or 2, wherein: The resin constituting the outer jacket has the same monomer unit as the outermost layer resin. The storage container according to claim 1 or 2, wherein: The inner container is configured to have an outer shell and an inner bag, and the inner bag shrinks with the content, The outermost layer and the adjacent layer are provided on the shell. A method of manufacturing a container, Equipped with an integral forming step of integrally forming the inner container and the outer jacket, Wherein, in the integral molding step, in a state where the outer peripheral surface of the inner container is arranged in a mold, a space outside the inner container in the cavity of the mold is filled with resin to form the outer casing , The inner container includes 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 method according to claim 8, wherein: In the integral molding step, the inner container is pressurized. The method according to Claim 8 or Claim 9, wherein: In the integral molding step, the resin is filled while pressing the inner surface of the bottom surface of the inner container with a support rod inserted into the inner container. A double-layer container is provided with an outer shell, an external air introduction hole, and an inner bag, wherein, The outer shell is configured to be pressable from the outside, and the pressing causes the contents contained in the inner bag to flow out from the mouth, The external air introduction hole is provided in a specific area on the bottom side of the casing, and the bottom side refers to the side away from the mouth when the double-layer container is divided into two in the height direction, And it is configured to be fitted with a check valve, through the check valve, after the content flows out, air is introduced into the intermediate space between the inner side of the housing and the outer side of the inner bag, so that the housing The shape is restored to its original shape, The inner bag is configured to be compressed and contracted by the air introduced into the intermediate space when the content decreases. The double-layer container according to claim 11, wherein: The mouth is configured as a cover mountable, The top surface of the cover can be placed upside down as a grounding surface. The double-layer container according to claim 12, wherein: The area of the top surface of the cover is S1, and the area of the mouth is S2, Satisfy S1≧1.5×S2. The double-layer container according to any one of claims 11 to 13, wherein: The specific area is a part of the side surface of the housing. The double-layer container according to any one of claims 11 to 13, wherein: The specific area is located in the recess of the housing and is configured to have an inclination angle with respect to the opening surface defining the recess. The double-layer container according to claim 15, wherein: The inclination angle is 5 degrees or more and 45 degrees or less. The double-layer container according to claim 15, wherein: The wall defining the recess is configured not to be perpendicular to the opening surface. The double-layer container according to claim 15, further comprising a groove part, wherein: The groove portion is provided on the housing at a position closer to the bottom side than the specific area. The double-layer container according to claim 18, wherein: The depth of the groove is shallower than the depth of the recess. The double-layer container according to any one of claims 11 to 13, wherein: The check valve is a ball valve. A double-layer container is provided with a container body, the container body is configured to have an outer shell and an inner bag and reduce the shrinkage of the inner bag with the content, wherein, The container body includes a cylindrical body and a bottom provided at the lower end of the body, The bottom includes a central recess provided in the center of the bottom and a peripheral portion surrounding the central recess, In the central recess, an external air introduction hole is provided on the housing, A spacer member for forming a gap between the outer shell and the inner bag is provided on the peripheral edge. The double-layer container according to claim 21, wherein: The spacing member is a protrusion provided on the outer shell or the inner bag. The double-layer container according to claim 21 or 22, wherein: The spacing member is arranged in a radial shape. The double-layer container according to claim 21 or 22, wherein: The spacing member is configured to form a discontinuous circle. The double-layer container according to claim 21 or 22, wherein: The container body is formed by heating the inner preform and the outer preform in a state where the inner preform constituting the inner bag is covered with the outer preform constituting the outer preform. of. The double-layer container according to claim 25, wherein: The inner preform is provided with a positioning pin at the bottom of the inner preform, The outer preform is provided with a positioning hole at the bottom of the outer preform, The blow molding is performed in a state where the positioning pin is inserted into the positioning hole. A method for manufacturing a double-layer container, With blow molding steps, Wherein, the blow molding step is performed in the following manner: in a state where the outer preform covers the inner preform, heating and softening the inner preform and the outer preform, and in this state Air is blown into the inner preform, The inner preform is a blow molded body, The blow molding step is performed in a state where the extension of the bottom of the outer preform is suppressed. The method according to claim 27, wherein: The outer preform has a reinforcement structure that suppresses the extension of the bottom of the outer preform. The method according to claim 28, wherein: The reinforcing structure is an annular convex portion provided at the bottom of the outer preform. The method according to any one of claims 27 to 29, wherein: The blow molding step is performed in a state where the bottom of the outer preform is supported by a bottom support mold to suppress the extension of the bottom.

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