JP3209231B2 - Multi-layer thin container with flange and method of manufacturing the container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin-walled container provided with a flange at an upper end of a container wall, and a method of manufacturing the container.
In particular, it relates to a multilayer thin container formed of a resin material having a plurality of resin layers and a method for manufacturing the container.

[0002]

2. Description of the Related Art Containers for packaging foods and the like include some or all of the following properties: mechanical strength, gas barrier properties, moisture resistance, heat resistance, and fragrance retention. Everything is required. It is known that each of these properties is achieved by a specific resin material.
If there are a plurality of desired properties as required, one container is formed by laminating individual resin materials achieving the properties.

[0003] Further, among the above-described containers having a multilayer structure, there is a container provided with a flange at an upper end of a container wall. As such a container, for example, a so-called winding cup container 1 as shown in FIG. 7 is known. This container 1
At the upper end of the container wall 3, there is provided a winding flange 2 for winding a metal lid (not shown) for sealing. The metal lid is wound around the flange 2 to seal the inside of the container. It is known that a sufficient sealing state cannot be obtained unless the thickness of the container flange is set to a predetermined value at the time of this tightening.
6 mm, preferably 0.4 to 0.5 mm. When sealing a flanged container manufactured by sheet molding described below by winding, most of the flanges are too thick, so hot pressing the flange portion, or performing secondary processing such as shaving the flange portion, It has a predetermined thickness.

Various methods as described below have already been proposed as methods for manufacturing the above-mentioned flanged multilayer structure container.

The first method is a so-called sheet forming method such as vacuum forming, pressure forming, plug assist forming and the like. In this sheet forming method, as shown in FIG. 8, a single sheet 51 having a multilayer structure is heated by a heater 52 while being conveyed at a predetermined feed pitch in the direction of arrow A.
The container 55 is formed by the molds 53 and 54 arranged opposite to each other.

In this sheet forming method, a large margin is formed between the individual containers 55 in accordance with the sheet feed pitch. Also, due to the structure of the dies 53 and 54, individual spaces are formed in the direction perpendicular to the sheet feed direction A. A large margin is formed between the containers 55. These margins are very uneconomic because they become so-called scrap which does not contribute as a product.

[0007] It is also practiced to collect scraps and reuse them for a part of the layer structure of the sheets 51 to recycle the sheets 51, and to manufacture containers 55 from the regenerated sheets. However, in this method, the resin forming the sheet 51 gradually deteriorates due to pulverization at the time of reproduction or heat at the time of extruding the sheet, and causes problems such as coloring, unpleasant odor and strength deterioration. That is, when the scrap is to be reproduced, a part of the layer of the sheet 51 is constituted by the scrap layer or the scrap mixed layer. The sheet 51 in which such a resin is reused changes the composition of the scrap every time it is recycled, so that the properties of the sheet 51 as a whole change and the performance of each container to be formed may vary.

Further, it is extremely difficult to manufacture the sheet 51 to have a uniform thickness, and the thickness is inevitably uneven. That is, generally, a film is formed by an inflation method, an extrusion method, a co-extrusion method, etc.
The thickness has a certain degree of variation, and it is extremely difficult to make the thickness of a sheet obtained by laminating these layers uniform. If the thickness of the sheet 51 is non-uniform, the thickness distribution of one container 55 becomes non-uniform with respect to the container 55 formed by the molds 53 and 54, and the thickness of each container 55 becomes non-uniform. Becomes Further, in forming the sheet, the container is formed by heating and softening the sheet 51. However, the heating temperature of the heater is not uniform in the width direction of the sheet 51, or the cooling condition of the mold is not uniform for each cavity. If it does, the thickness within the container and between the containers will also be non-uniform. When such a thickness variation, especially when a portion thinner than a predetermined size is formed in the container,
Failures such as insufficient mechanical strength (eg, buckling strength) of the container and deformation of the container during heat sterilization after filling the contents occur.

As a second example of a method for manufacturing a multilayered container with a flange, there is a method disclosed in Japanese Patent Publication No. 57-1415. In this method, a square-shaped multilayer sheet material is heated, further press-molded to produce a disc-shaped preform, and the disc-shaped preform is molded by vacuum molding or the like to produce a product container. is there.

According to this method, scrap can be considerably reduced as compared with the above-described sheet forming. However, when a multilayer sheet material is press-formed to form a preform, it is necessary to heat the sheet material to a high temperature to reduce its viscosity. In this case, the layer structure of the multilayer sheet material is likely to collapse. That is, the layer is partially thinned or is easily separated. For a product container formed from a multilayer sheet material having a collapsed layer structure, a target specific function such as gas barrier properties cannot be obtained.

Further, a good preform cannot be obtained unless a resin having good fluidity is used as a resin in contact with a mold for molding the preform. That is, the resin that can be used as the multilayer sheet material is limited to a narrow range.

Further, as a method of manufacturing a container using a preform, JP-A-60-178020 and JP-A-60-178020 can be used.
No. 244518, No. 63-130330 and No. 63-
There is a so-called injection blow method disclosed in each publication of 296921. In the injection blow method, a disc-shaped preform is molded by injection molding, and the preform is subjected to molding processing such as plug-assist molding to form a container.

In the injection blow method, since the injection molding method, that is, the injection molding method is used in the step of molding the preform, it is extremely difficult to form the preform into a multilayer structure. Only a preform is made. Therefore, there is a problem that a container having a specific function such as gas barrier property cannot be manufactured.

When a preform is formed by injection molding, for example, as shown in Japanese Patent Application Laid-Open No. 3-176126, if a preform is formed by using a plurality of injection devices and a multi-layer injection nozzle, a multi-layered preform is formed. Reforms can be manufactured. In this case, the layer configuration becomes symmetrical, and for example, research is progressing toward the practical use of cup-shaped containers and bottles having a gas barrier resin as an intermediate layer. However, according to this technique, not only is it extremely difficult to make the thickness of each resin layer uniform, but also, in many cases, near the end of the cavity where the flowing resin finally reaches, the multilayer structure itself does not hold. Thus, it is not possible to provide a uniform multilayer structure over the entire preform. Further, when a large number of resins need to be laminated in an asymmetric layer configuration as in the present invention, this method cannot be applied.

As another example of a method for manufacturing a multilayered container with a flange, JP-A-2-45352 and JP-A-2-8-8
There is a method disclosed in each publication of No. 0519. In this method, a cup-shaped container is preformed by sheet molding, and an outer layer is formed on the outer periphery of the container by injection molding to manufacture the container.

In the injection molding, a resin is poured into a gap in a mold. If the gap does not have a certain thickness or more, sufficient molding cannot be performed. Therefore, the conventional method has a problem that the thickness of the container wall of the completed container is too large.

[0017]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned various problems, and is intended to provide a thin-walled container having a multilayer structure without breaking its layer structure. Further, it is a first object of the present invention to reduce scrap generation as much as possible and to manufacture economically.

The present invention also provides a sufficient tightening strength by forming a thin flange (for example, reference numeral 2 in FIG. 7) provided at the upper end of the container wall (for example, reference numeral 3 in FIG. 7). It is a second object of the present invention to provide a thin-walled container with a flange that enables a metal lid to be wound with a container and a method for manufacturing the container.

The third object of the present invention is to provide a thin-walled container with a flange in which a resin layer having a specific function surely exists in the flange, and a method of manufacturing the container.
The purpose of.

[0020]

In order to achieve the above object, a multi-layer thin container with a flange according to the present invention comprises:
The container wall and the flange are integrally formed by applying a molding process to a preform in a state in which the peripheral supporting portion is supported, and the preform is formed by injection molding on a surface of a sheet material including a resin layer having a specific function. It is formed by laminating an injection resin layer, and the preform in a molded state has a step for forming a flange at a place other than the peripheral support portion, and the flange has a step for forming the flange. It is formed by cutting.

Further, the method for manufacturing a multilayer thin-walled container with a flange according to the present invention includes a sheet mounting step of mounting a sheet material including a resin layer having a specific function in a mold, and a mold in which the sheet material is mounted. An injection molding step of injecting a resin into the preform to form a preform, and molding the preform while supporting the peripheral support of the preform to form a product container integrally with the peripheral support. And a container cutting step of cutting the product container from the peripheral support portion of the preform, and in the container molding step, the product container is molded so as to have a step portion for forming a flange, In the container cutting step, the product container is cut from the peripheral edge support portion with the flange forming step as a boundary.

In the above structure, the resin layer having a specific function refers to a resin layer having various functions such as gas barrier properties, moisture proof properties, heat resistance properties, and fragrance retention (non-adsorptive properties). When laminating resins having poor adhesion, an adhesive layer provided between the layers and acting as an adhesive is also considered as a resin layer having a specific function. As a resin layer for achieving each of these functions, the following resin layers can be applied, respectively. Gas barrier properties: saponified ethylene-vinyl acetate copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl alcohol (PVA) Moisture resistance: Polyamide (nylon), polypropylene, polyolefin incorporated with desiccant Heat resistance: polyester, polycarbonate, polypropylene Scent retention: polyester (PET), saponified ethylene-vinyl acetate copolymer (EVOH), polyacrylonitrile (PAN) Adhesive layer: ionomer, ethylene-vinyl acetate copolymer (EVA)

As the molding method, vacuum molding, air pressure molding, plug assist molding and the like can be considered. Vacuum forming is a forming method in which the inside of the cavity is evacuated and the sheet material is deformed so as to be in close contact with the mold, thereby forming. Compressed air molding is a molding method in which a sheet material is pressed by air and brought into close contact with a mold to form the sheet material. The plug assist molding is a molding method in which the sheet material is assisted by a plug to form the sheet material in the vacuum forming or the pressure forming.

The resin layer laminated on the sheet material by injection molding mainly gives the container a mechanical strength, and for example, polypropylene (PP), styrene, polyester, vinyl chloride or the like is used.

[0025]

When manufacturing a multilayer thin container, first, a sheet material containing at least one layer resin is prepared, formed into a predetermined shape by punching or the like, and then attached to an injection mold. . Next, a single-layer resin such as polypropylene (PP) is laminated on the sheet material by injection molding to form a preform. Then, the part of the product container is formed by forming the preform. The molded product container portion is cut from the preform peripheral edge support portion at the flange forming step to form a product container.

Since press molding is not used when molding the preform, the layer structure of the sheet material, that is, the layer structure of the preform does not collapse. In addition, since the preform is formed by a combination of the preformed sheet material and injection molding, even if the sheet material has some thickness variation, the variation is absorbed by the injection process, and the entire preform is formed. The thickness can be homogenized very precisely. Therefore, a container having a uniform thickness can be manufactured. Even in that case, the layer structure inside the container wall does not collapse.

Since a preform is formed one by one and molded into a product container, no scrap is generated unlike the conventional sheet molding method, and therefore, it is very economical. In this case, a large number of sheet materials to be mounted on the mold are created by, for example, punching or cutting one large sheet. At this time, since the sheet can be punched at a very high density, a large amount of scrap is not generated. In addition, when the resin layer is laminated by injection molding, almost no scrap is generated. The generation of scrap is extremely small.

A flanged multilayer thin container as a product container cuts a flange forming step in a preform in a state where molding is completed, that is, a semi-finished product in which a peripheral support portion and a product container portion are still integrated. Obtained by: Since the flange forming step is a part extended by molding, the thickness thereof is thin. When the step is pressed during molding, the flange becomes thinner and has a uniform thickness. Therefore, if this portion is used as a flange of the multilayer thin-walled container, the metal lid can be wound with a sufficient tightening strength. The peripheral supporting portion does not affect the thickness of the obtained product container, so that the peripheral supporting portion can have a necessary thickness so as to sufficiently support the preform during molding.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multilayer thin container 1 having the shape shown in FIG.
An example will be described with reference to an example of the case of manufacturing.

The container 1 has the following steps, ie, FIG.
A sheet material preparing step for preparing a disk-shaped sheet material 5 having a single-layer or multilayer structure as shown in FIG. 5 and an injection resin formed by injection molding on one surface (the lower surface in the figure) of the disk-shaped sheet material 5 as shown in FIG. An injection molding step of forming a preform 7 by laminating 6; a container molding step of forming the formed preform 7 to form a cup-shaped container 1 as a product container as indicated by a chain line; It is manufactured by a container manufacturing process including a container cutting process of cutting the cup-shaped container 1 at a position indicated by X-rays.

As will be described in detail later, the peripheral portion C of the preform 7 is a peripheral support portion for supporting the preform 7 with a clamp or the like in the container forming step and the container cutting step of the preform. Further, the step portion E is a portion that remains as the winding flange 2 in FIG. 7 after the above-described container cutting step is completed.

In the above-described container manufacturing step, a preform heating step for preheating the preform 7 formed by the injection molding step may be added between the injection molding step and the container molding step, if necessary. it can.

The sheet material 5 shown in FIG. 4 is formed in a specific single-layer structure or multi-layer structure in order to obtain target specific functions, for example, gas barrier properties, moisture-proof properties, heat-resistance properties, and fragrance-retaining properties (non-adsorption properties). Is done. For example, as a two-layer structure, PET / EVOH, PET / PVDC, etc., from the direction corresponding to the inside of the container, and as a three-layer structure, PET / EVOH / PP, PP / PVDC / PP, etc. can be considered. In addition, PET is polyester EVOH, saponified ethylene-vinyl acetate copolymer PP, polypropylene PVDC is polyvinylidene chloride. Further, an adhesive or an adhesive resin layer is present between the respective layers of the sheet material 5 as necessary.

The method for manufacturing the sheet material 5 is not limited to a special method, and any method can be used. For example, one large sheet having a target layer configuration is formed by an arbitrary sheet forming method, for example, an adhesive laminating method, a co-extrusion method or the like, and a large number of discs are formed from the single sheet by punching. The sheet material 5 can be manufactured. Since the punching can be performed at a high density, that is, the individual disk-shaped sheet materials 5 can be punched from very close positions, there is no fear that a large amount of scrap remains on the raw material sheet after the punching.

The resin laminated on the sheet material 5 in the injection molding process is a thermoplastic resin having mechanical strength capable of giving a desired shape to the container, for example, polypropylene (PP), polystyrene (PS), polystyrene. Vinyl chloride (P
VC), polycarbonate (PC) and the like.

As used herein, the term “molding” refers to preform 7
Is a processing method in which a desired shape, for example, a cup shape is processed by stretching. For example, vacuum forming, pressure forming,
Plug assist molding or the like can be employed.

The preform heating step inserted between the injection molding step and the container molding step as necessary is a step for preliminarily heating the preform 7 before the container is molded. This step is performed in order to reliably fuse the disc-shaped sheet material 5 and the injection-molded layer laminated thereon, and to raise the temperature of the preform 7 to a temperature at which the preform 7 can be easily formed. When the container molding step is started immediately after the preform is formed by injection molding, the preform heating step may not be required. This is because the sheet material 5 is heated by the injected high-temperature resin. If the time from injection molding to container molding is relatively short, only the sheet material 5 of the preform 7 may be heated. On the other hand, when the time from injection molding to container molding is long and the preform 7 is completely cooled,
Both the sheet material 5 and the injection resin layer are heated.

Hereinafter, a method of manufacturing the multilayer thin container 1 (FIG. 7) will be described in detail with reference to a specific example of a container manufacturing apparatus. FIG. 1A shows an embodiment of an apparatus for performing an injection molding process. The injection molding device 24 has a fixed plate 8 at the uppermost portion, and the core 9 is fixed to the lower surface of the fixed plate 8. A coolant passage 10 and an air suction passage 22 are provided inside the core 9. A lip cavity 11 and a lip plate 12 are provided around a lower portion of the core 9. Further, a cavity 13 held by a holding plate 14 is provided below the core 9.
The tip of the hot runner 15 projects inside the gate 16
Is in contact with

The core 9 can be reciprocated linearly in the vertical direction as shown by arrows AA 'together with the fixed plate 8.
It moves between the illustrated clamping position and an open position (not shown) far away from the cavity 13. The mold clamping position is a position where a gap G corresponding to a desired preform shape is formed between the core 9 and the cavity 13.

The lip cavity 11 is of a so-called split type, and the right and left lip cavities can reciprocate linearly in the left and right directions as indicated by arrows BB 'with respect to the center axis L. Due to this movement, the lip cavity 11 moves between the illustrated mold clamping position and an open position (not shown) which is largely separated from each other.

FIG. 2 shows an embodiment of an apparatus for performing a preform heating step. This preform heating device 25 is used in an injection molding process (FIG. 1A) which is a preceding process.
Has a heater 17 which can protrude above the preform 7 formed by the above. A heater 30 for heating the injection resin layer 6 is provided below the preform 7. This heater 30 can be omitted when the process proceeds to the container molding step immediately after the lamination of the injection resin layer 6.

FIG. 1B shows a plug assist molding apparatus 26 which is an embodiment of an apparatus for performing a container forming step and a container cutting step. This device has a lower mold 18 connected below the lip cavity 11, a core 19 movable in the vertical direction, and a plug 20 penetrating the core 19 and movable in the vertical direction. Lower mold 18
Is provided with a recess 21 having an inner wall surface that matches the shape of the product container 1 (FIG. 7).

As shown in an enlarged view in FIG. 6, a disc-shaped (disc-shaped centering on the center line L) pressing member 40 is provided at the lower end of the core 19, and a ring-shaped ( A ring-shaped cutter 41 centered on the center line L is provided. The pressing member 40 is driven by a driving mechanism (not shown), and can reciprocate vertically in the drawing independently of the core 19. The ring-shaped cutter 41 is driven by a drive mechanism (not shown), and can reciprocate vertically in the drawing independently of the core 19 and the pressing member 40.

A ring-shaped (ring-shaped centering on the center line L) groove 42 is provided in the lower die 18 at a position facing the ring-shaped cutter 41, and a ring-shaped receiving member is provided in the groove 42. 43 are provided. The ring-shaped receiving member 43 is normally urged by a spring or other elastic urging means and is placed at the position shown in the figure. Ring cutter 41
When the receiving member 43 descends and presses the receiving member 43, the receiving member 43 descends in the groove 42.

The air introduction hole 23 is formed in the core 19 and the pressing member 40. Hereinafter, each step will be described.

(Injection Molding Step) In FIG. 1A, the core 9 and the lip cavity 11 are both
To an open position (not shown) that is far away from the camera.
Thereby, the upper surface of the cavity 13 is largely opened. In this state, as shown in FIG. 3, the disc-shaped sheet material 5 (see FIG. 4) is attached to the lower end of the core 9. The sheet material 5 is suction-fixed to the lower end of the core by the air flowing through the air suction path 22. The upper surface of the mounted sheet material 5, that is, the surface in contact with the core 9 becomes the inner wall surface of the container.

When the sheet material 5 is mounted on the lower end of the core 9, the core 9 and the lip cavity 11 are set at the mold clamping position as shown in FIG. In this state, the resin flows into the cavity recess G through the hot runner 15. Thus, the injection resin layer 6 (FIG. 5) is laminated on the lower surface of the sheet material 5 to form the preform 7 as shown by the solid line in FIG. When the preform 7 is formed, the process proceeds to the next preform heating step.

(Preform Heating Step) When the injection molding is completed, the core 9 moves from the mold clamping position to the open position in FIG. The lip cavity 11 continues to hold the peripheral edge support portion C (FIG. 5) of the preform 7 while remaining at the mold clamping position. Thereafter, the preform 7 is sent to the heating stage shown in FIG. 2 while being held by the lip cavity 11. In this heating stage, the heater 17 is carried out to a position immediately above the preform 7, and the heat radiated from the heater 17 heats the preform 7. By this heating, fusion between the sheet material 5 and the injection resin layer 6 (FIG. 5) is promoted, and further, preliminary heating for the next step of forming a container is performed. This step can be omitted in some cases.

(Container Forming Step) After the preform heating step is completed, the preform 7 is then held in a state in which the peripheral support portion C is held by the lip cavity 11, as shown in FIG.
In this container molding stage, the core 19 having the plug 20 and the pressing member 4 are sent.
0 is set at the illustrated molding position from above the preform 7, and the container molding process is performed. That is, plug 2
By the downward movement of 0, the preform 7 is pressed downward,
At the same time, the preform 7 is extended by air sent through the air introduction hole 23. The preform 7 extended in this manner is formed into a wall shape of the lower mold concave portion 21, that is, a cup shape, and a product container portion shown by a chain line in FIG. 5 is formed.

(Container Cutting Step) When the container forming step is completed, the pressing member 40 and the cutter 41 or only the pressing member 40 are moved downward in FIG. 1B and FIG. The pressed preform, that is, the flange step E (see FIG. 5) of the preform 7 'as a semi-finished product is pressed from above. Thereby, the step portion E has an appropriate thickness for tightening, that is, 0.4 to
It is formed to a thickness of 0.6 mm, preferably 0.4 to 0.5 mm.

Thereafter, while the pressing member 40 is not moved, only the ring-shaped cutter 41 is lowered to push the flange step E off. Thereby, the product container portion of the semi-finished product preform 7 ′ is cut from the peripheral edge support portion C, and the product container,
That is, the cup-shaped container 1 shown in FIG. 7 is completed.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the embodiments. For example, the device for cutting the semi-finished product preform 7 'is not limited to the device shown in FIG. 1B or FIG. 6, but may have any other configuration. Instead of being incorporated in a mold as shown in the figure, a dedicated device may be separately provided. Also, the shape of the product container can be an arbitrary shape (for example, a square tray shape). In this case, it is obvious that the shape of the sheet material 5 is prepared in a shape corresponding to the shape of the product container. Also,
If necessary, the injection molding step can be repeated a plurality of times to form two or more injection molded resin layers.

In the above embodiment, the container is manufactured by using the sheet material side as the inner surface side of the container. Conversely, the injection resin layer side may be used as the inner surface side of the container. When the sheet material side is set to the inner surface side of the container as in the above embodiment, the following advantages are obtained. That is, a material that can be preferably used for the sheet material 5 is a material having a specific function, such as a saponified ethylene-vinyl acetate copolymer that is a gas barrier resin and a polyester resin that is a non-adsorbent resin, On the other hand, since the resin of the injection resin layer is a resin such as polypropylene which is a main structural material of the container, the resin of the injection resin layer is generally more suitable for molding into a container shape such as sheet molding. Therefore, when the sheet material is formed, by disposing the sheet material 5 on the inner surface side of the container, it is possible to prevent molding failure of the sheet material 5 (thickness variation, cracking, etc. due to insufficient elongation during sheet molding). When a non-adsorbent resin is used for the sheet material 5, the purpose can be achieved only when the resin is disposed at a position in contact with the contents, and therefore, it is preferable that the resin be manufactured in a positional relationship as in the above embodiment. .

[0054]

According to the present invention, a preform is formed by performing injection molding in a state where a sheet material is mounted in a mold. A multi-layered preform of high quality can be obtained.

Since preforms are formed one by one by injection molding and a product container is formed from the preform, unnecessary components such as scraps are hardly generated. Therefore, it is very economical.

Since the preform is made by injection molding instead of press molding, the layer structure in the preform does not collapse. Therefore, specific functions such as gas barrier properties can be reliably obtained.

Since the injection molding is used, the preform has extremely high precision in thickness. Since the preform having a uniform thickness is formed into a container shape to produce a product container, the preform is thin and has a small thickness in the container and between containers. It is possible to produce a container having stable thickness accuracy without variation.

The part of the preform which becomes the flange 2 in the product container (FIG. 7) is a flange forming step (E: FIG. 5) which is extended by molding. Therefore, the flange can be formed to a uniform and thin thickness. This is advantageous when using the flange to wind up a metal lid.

In FIG. 3, when the sheet material 5 is mounted on the core 9, the mounting position may be shifted. Even in the case where the mounting position of the sheet material 5 shifts as described above, the sheet material 5 always exists in the flange forming step E in FIG. As a result, the sheet material 5 always exists in the entire area of the flange 2 of the cup-shaped container 1 in FIG. The sheet material 5 includes a resin layer having a specific function such as gas barrier properties. Therefore, sheet material 5
Is present in the entire area of the flange 2, which means that gas barrier properties and the like can be ensured as a whole container.

According to the container manufacturing method of the third aspect, the flange can be formed to be thinner and more uniform.

[0061]

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an example of an apparatus for producing a multilayer thin container according to the present invention. In particular, FIG.
It is a side sectional view showing an example of an injection molding device. Also,
(B) is a side sectional view showing an example of the container forming device and the container cutting device.

FIG. 2 is a side sectional view showing one embodiment of a preform heating apparatus.

FIG. 3 is an enlarged sectional view showing a main part of FIG. 1 (A).

FIG. 4 is a perspective view showing one embodiment of a sheet material.

FIG. 5 is a diagram showing a preform and a product container.

FIG. 6 is an enlarged view showing a main part of FIG. 1 (B).

FIG. 7 is a perspective view showing an embodiment of the multilayer thin container according to the present invention.

FIG. 8 is a perspective view showing an example of a conventional container manufacturing apparatus.

[Explanation of symbols]

2 Flange for winding 3 Container wall 5 Sheet material 6 Injection resin layer 7 Preform 9 Core 11 Rip cavity 13 Cavity 24 Injection molding device 26 Container molding device 40 Flange pressing member 41 Cutter 42 Groove 43 Cutter receiving member C Preform Peripheral edge support E Step for forming flange of preform

Continuation of the front page (56) References JP-A-4-358822 (JP, A) JP-A-53-83884 (JP, A) JP-A-60-178020 (JP, A) JP-A-63-99913 (JP) , A) JP-A-60-244518 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 51/00-51/46 B29C 49/00-49/80 B29C 69/00 -69/02 B29D 22/00

Claims (3)

(57) [Claims] 1. A thin-walled container provided with a flange at an upper end of a container wall, wherein the container wall and the flange are integrally formed by molding a preform in a state in which a peripheral supporting portion is supported. The preform in the molded state is formed by laminating an injection resin layer by injection molding on the surface of a sheet material containing a resin layer having a specific function. The multilayer thin-walled container with a flange, characterized in that the flange is formed by cutting the flange forming step. 2. A method of manufacturing a multilayer thin-walled container with a flange having a flange at an upper end of a container wall, comprising: mounting a sheet material including a resin layer having a specific function in a mold; An injection molding step of injecting a resin into a mounted mold to form a preform, and performing a molding process on the preform while supporting the peripheral support portion of the preform, thereby forming a product integrally with the peripheral support portion. It has a container forming step of making a container, and a container cutting step of cutting the product container from the peripheral support portion of the preform. In the container forming step, the product container is formed so as to have a step portion for forming a flange. In the container cutting step, the product container is cut from the peripheral supporting portion with the flange forming step as a boundary. 3. The method according to claim 1, wherein a step of pressing the flange forming step formed in the container forming step to reduce the thickness of the step is provided between the container forming step and the container cutting step. The method for producing a multilayer thin-walled container with a flange according to claim 2.