Container manufacturing method, container manufacturing device, and container

Abstract

A container having an uneven inner surface is manufactured. This container manufacturing method is characterized by comprising: a step (A) for forming a tubular parison having recesses and protrusions on the outer surface thereof; a step (B) in which the parison is sandwiched by a model; and a step C for expanding the parison from the inside to form the container, in which in step A, an opening of a mold from which the resin is extruded has a shape having irregularities on the outer periphery, and the resin is extruded from the mold to form the parison having irregularities on the outer surface, and irregularities are formed on the inner surface of the formed container.

Description

Technical Field

[0001] The present invention relates to a container having portions with different wall thicknesses, a method for manufacturing the same, and a manufacturing apparatus therefor. Background Art

[0002] Conventional direct blow molding apparatuses include: a parison forming die (hereinafter simply referred to as "die") that extrudes a molten plastic resin into a tubular shape to form a parison; a core provided at the center of the thermoplastic resin discharge port of the die; and a container die that clamps the parison with one end thereof closed and expands the parison from the inside to form a container shape.

[0003] In addition, an invention in which a groove is formed in the core in a conventional direct blow molding apparatus in order to be able to mold a container having different wall thicknesses in the circumferential direction of the container has been disclosed (see Patent Document 1). Through the groove of the core, a wall thickness portion is formed in the height direction on the inner surface of the parison extruded from the die. Then, the parison is placed in the above-described container die, and the parison is expanded into the shape of a container, thereby forming a container having different wall thicknesses in the circumferential direction on the inner surface.

[0004] However, although a conventional direct blow molding apparatus can form different wall thicknesses in the circumferential direction by forming ribs (ridges) in the height direction on the inner surface of the container, it cannot manufacture a container having continuous unevenness in the circumferential direction on the inner surface of the container, and there is even no such concept. In addition, there is no container having continuous unevenness in the circumferential direction on the inner surface of the container.

[0005] In addition, when forming unevenness on the outer surface side of the container, it can be easily achieved by simply designing the container die that clamps the parison to have an uneven shape, but it is impossible to form a container having unevenness or different wall thicknesses on the inner surface side.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Problems to be Solved by the Invention

[0007] In view of this, the inventors of the present invention have intensively studied to form unevenness in the circumferential direction on the inner surface of the container, and through repeated experiments, the present invention has finally been completed. The present invention is proposed based on the above problems, and one of its objects is to provide a container having unevenness in the circumferential direction on the inner surface side, a method for manufacturing the same, and a manufacturing apparatus therefor.

Means for Solving the Problems

[0008] One embodiment of the present invention relates to a method for manufacturing a container, characterized by including: step A of forming a tubular preform having unevenness on the outer surface; step B of clamping the preform with a mold; and step C of expanding the preform from the inside to form a container, wherein, in step A, the opening of the die from which the resin is extruded has a shape with unevenness on the outer periphery, and the resin is extruded from the die to form a preform having unevenness on the outer surface, and unevenness is formed on the inner surface of the container formed through step C.

[0009] According to this structure, by extruding the resin for forming the preform from a die having unevenness on the outer periphery of the opening, a preform having unevenness on the outer surface is formed. Thus, the wall thickness of the extruded preform is different in the circumferential direction. In a state where the preform is clamped with a mold, the preform is expanded from the inside with air or the like, so that unevenness can be formed on the inner surface of the container. The unevenness formed by this manufacturing method is formed in the circumferential direction, and the concave and convex portions are smoothly continuous.

[0010] In addition, the method for manufacturing a container is characterized in that, in step A, the opening of the die has a shape in which concave and convex portions are alternately and continuously connected in the circumferential direction. According to this structure, a container in which concave and convex portions are alternately and continuously connected in the circumferential direction on the inner surface can be manufactured.

[0011] In addition, the method for manufacturing a container is characterized in that, in step A, the opening of the die is formed in a gear shape. According to this structure, a container having a gear-shaped cross section and in which concave and convex portions are alternately and continuously connected in the circumferential direction on the inner surface can be manufactured.

[0012] In addition, the method for manufacturing a container is characterized in that, in step A, the concave and convex portions of the opening of the die are smoothly connected. According to this structure, a container in which concave and convex portions are smoothly connected in the circumferential direction on the inner surface can be manufactured.

[0013] In addition, in step A of the method for manufacturing a container, a core is inserted through the center of an insertion hole communicating with the opening of the die, and resin is extruded from the gap between the opening of the die and the core to form a tubular preform having different wall thicknesses in the circumferential direction.

[0014] In addition, the method for manufacturing a container is characterized in that, in step C, the preform clamped by the mold is expanded from the inside with air, so as to form a container having no unevenness on the outer surface and having unevenness with different wall thicknesses in the circumferential direction on the inner surface. According to this configuration, a container having no unevenness on the outer surface and having unevenness with different wall thicknesses in the circumferential direction on the inner surface can be easily manufactured.

[0015] In addition, the method for manufacturing a container is characterized in that in step A, when the resin for forming the preform is extruded from the mold, the core or the mold moves up and down continuously to extrude a preform with different wall thicknesses continuously. According to this structure, the core or the mold moves up and down continuously, so that the gap between the core and the mold changes, and the amount of resin extruded therefrom also changes.

[0016] As a result, the wall thickness of the extruded preform is different in the height direction. In a state where the preform is clamped by a mold, the preform is inflated from the inside by air or the like, so that unevenness can be formed on the inner surface of the container. The unevenness formed by this manufacturing method is formed in the height direction, and unevenness in which the concave portion and the convex portion are smoothly continuous is formed.

[0017] In addition, the method for manufacturing a container is characterized in that in step A, the core or the mold moves up and down at a specified interval and with a specified amplitude. According to this structure, a container with a specified wall thickness can be manufactured at a specified interval.

[0018] In addition, the method for manufacturing a container is characterized in that in step A, the core or the mold can move up and down to form continuous unevenness over the entire length in the height direction of the inner surface of the container. According to this structure, a container can be manufactured in which continuous unevenness is formed over the entire length in the height direction of the inner surface of the container.

[0019] In addition, the method for manufacturing a container is characterized in that the formed container is formed with different wall thicknesses in the circumferential direction. According to this structure, a container can be manufactured in which there are portions with different wall thicknesses of the peripheral wall in the circumferential direction of the container.

[0020] In addition, the method for manufacturing a container is characterized in that the formed container is formed with different wall thicknesses in the height direction. According to this structure, a container can be manufactured in which there are portions with different wall thicknesses of the peripheral wall in the height direction of the container.

[0021] In addition, the method for manufacturing a container is characterized in that step A includes a step of clamping the lower end of the preform that sags after being extruded from the mold and twisting the preform in the circumferential direction while clamping the lower end of the preform. According to this structure, a container having spiral unevenness on the inner surface can be manufactured.

[0022] In addition, the method for manufacturing a container is characterized in that in step A, the core is arranged at a position eccentric from the center position of the hole provided in the center of the mold, and the wall thickness of the preform extruded from the mold is formed such that a part of the peripheral wall is thinner than the other part of the peripheral wall, so that the formed container is formed with different wall thicknesses in the circumferential direction.

[0023] According to this structure, the core is disposed at a position eccentric from the center position of the hole in the center of the mold, so that the gap between the core and the mold changes left and right, and the amount of resin extruded therefrom also changes. As a result, the wall thickness of the extruded parison is different in the circumferential direction. In a state where the parison is clamped by a mold, the parison is inflated from the inside by air or the like, so that a container having a different wall thickness in the circumferential direction can be formed.

[0024] A container manufacturing apparatus according to an embodiment of the present invention is characterized by including: a structure A for forming a tubular parison having unevenness on the outer surface; a structure B for clamping the parison with a mold; and a structure C for expanding the parison from the inside to form a container, wherein the structure A is a structure in which the opening of the mold from which the resin is extruded has a shape having unevenness on the outer circumference, and the resin is extruded from the mold to form a parison having unevenness on the outer surface, and unevenness is formed on the inner surface of the formed container. According to this structure, by using this manufacturing apparatus, a container having unevenness formed in the circumferential direction on the inner surface can be manufactured.

[0025] In addition, a structure that can be adopted by the container manufacturing apparatus is that the opening of the mold has a shape in which concave portions and convex portions are alternately and continuously connected in the circumferential direction.

[0026] In addition, a structure that can be adopted by the container manufacturing apparatus is that the opening of the mold is formed in a gear shape.

[0027] In addition, a structure that can be adopted by the container manufacturing apparatus is that the concave portion and the convex portion of the opening of the mold are smoothly connected.

[0028] In addition, a structure that can be adopted by the container manufacturing apparatus is that there is a core at the center through which an insertion hole communicating with the opening of the mold is inserted, and resin is extruded from the gap between the opening of the mold and the core to form a tubular parison having a different wall thickness in the circumferential direction.

[0029] In addition, a structure that can be adopted by the container manufacturing apparatus is that the core or the mold can move up and down, and when the resin for forming the parison is extruded from the mold, the core or the mold moves up and down to continuously extrude a parison having a different wall thickness.

[0030] In addition, a structure that can be adopted by the container manufacturing apparatus is that the core or the mold moves up and down at a specified interval and a specified amplitude.

[0031] In addition, a structure that can be adopted by the container manufacturing apparatus is that the formed container is formed with different wall thicknesses in the circumferential direction.

[0032] In addition, a structure that can be adopted by the container manufacturing apparatus is that the formed container is formed with different wall thicknesses in the height direction.

[0033] In addition, the structure that the container manufacturing apparatus can adopt is such that the structure A has a configuration of clamping the lower end of the parison that droops from the die and twisting the parison in the circumferential direction while clamping the lower end of the parison.

[0034] In addition, the structure that the container manufacturing apparatus can adopt is such that the core or the die can move in the horizontal direction.

[0035] A feature of the container according to one embodiment of the present invention can be that the outer surface is flat and continuous concavities and convexities are formed in the circumferential direction of the inner surface. According to this structure, a container with a flat outer surface and continuous concavities and convexities formed in the circumferential direction of the inner surface, which could not be manufactured in the past, can be produced.

[0036] In addition, the container has continuous concavities and convexities formed over the entire length in the circumferential direction of the inner surface.

[0037] In addition, the continuous concavities and convexities of the container are in a shape in which the concave portions and the convex portions are alternately and continuously connected in the circumferential direction.

[0038] In addition, the container has continuous concavities and convexities formed in the height direction of the inner surface.

[0039] In addition, the container has continuous concavities and convexities formed over the entire length in the height direction of the inner surface.

[0040] In addition, the container is formed with different wall thicknesses in the circumferential direction.

[0041] In addition, the container is formed with different wall thicknesses in the height direction.

[0042] In addition, the continuous concavities and convexities on the circumferential direction of the inner surface of the container are formed in a spiral shape.

Effects of the Invention

[0043] The present invention can produce a container having concavities and convexities in the circumferential direction on the inner surface side. Detailed Description of the Embodiment

[0044] <Container Manufacturing Apparatus> Hereinafter, one embodiment of the present invention will be described in detail based on the drawings, but the present invention is not limited to the following embodiment. Figure 1 It is a schematic diagram of a container manufacturing apparatus showing the container manufacturing process according to the first embodiment of the present invention. Figure 2 It is a cross-sectional view of the parison forming machine of the container manufacturing apparatus. Figure 3 It is a cross-sectional view of the main part of the parison forming machine. Figure 4 It is an X-X cross-sectional view, where (a) is a view showing the core disposed, and (b) is a view not including the core. Figure 5 It is an explanatory diagram for explaining the movement of the core of the parison forming machine.Figure 6 This is the control diagram of the control core.

[0045] (1. Overall Structure) First, the container manufacturing apparatus will be described, in the order of the container manufacturing method and the container. This manufacturing apparatus is a container manufacturing apparatus 1 (hereinafter referred to as "direct blow molding apparatus 1") capable of easily manufacturing a container having unevenness on the inner surface by direct blow molding.

[0046] As Figure 1 shown, the direct blow molding apparatus 1 includes a preform molding machine 5 that forms a tubular preform 4 and a container molding machine 6 that expands the preform 4 into a container shape to obtain a container 2. Then, the resin 3 in a molten state is extruded into the preform 4 by the preform molding machine 5, and in a state where the preform 4 is clamped in the container molding machine 6, air is blown into the inside of the preform 4 to expand it, thereby forming a container. In addition, in the direct blow molding apparatus 1, the container molding machine 6 is configured to be movable freely relative to the preform molding machine 5.

[0047] (2. Preform Molding Machine) As Figure 1 、 Figure 2 shown, the preform molding machine 5 heats the thermoplastic resin 3 and extrudes the resin 3 that has become molten due to heating into a tubular shape, thereby forming the preform 4. As an example of this embodiment, the resin 3 having thermoplasticity uses polyethylene terephthalate (PET), but other thermoplastic resins may also be used.

[0048] The preform molding machine 5 has a die head body 8 for extruding the molten thermoplastic resin into a tubular shape to form the preform 4, and a resin material supply unit 7 for supplying the molten resin 3 to the die head body 8.

[0049] The resin material supply unit 7 has a resin material inlet 11 in the shape of a funnel, a cylindrical heating cylinder 12 provided below the resin material inlet 11 for heating the resin material, an extrusion screw 13 for extruding the resin material inside the heating cylinder 12, and a motor 14 for driving the extrusion screw 13.

[0050] The extrusion screw 13 is disposed coaxially with the heating cylinder 12 inside the heating cylinder 12 and has a cylindrical shape, and has spiral teeth on the outer periphery. The extrusion screw 13 is rotated by the motor 14. Thus, the resin 3 located inside the heating cylinder 12 is extruded to the die head body 8.

[0051] (3. Die Head) As Figure 2 、 Figure 3As shown, a mandrel 18 that forms a die for extruding a thermoplastic resin in a tubular molten state is nested within a die head body 8, and an annular channel 19 is formed between the inner peripheral surface of the die head body 8 and the outer peripheral surface of the mandrel 18.

[0052] In addition, an annular die 20 is provided at the end of the die head body 8, and a core 30 is provided that is inserted through the center of an insertion hole 21 communicating with the opening 20A of the die 20 and whose front end is flush with or protrudes from the die 20.

[0053] And, as Figure 4 shown in (a) and (b) of

[0054] the opening 20A of the die 20 for extruding the resin has a shape with concavities and convexities on its outer periphery. The convex portions 20a and the concave portions 20b are formed in a gear shape such that they are alternately uniformly continuous and smoothly connected in the circumferential direction. The convex portions 20a have the same shape as each other. As an example, in the die 20 of the present embodiment, a structure is adopted in which eight convex portions 20a are formed at equal intervals in the circumferential direction of the die 20, but the number of convex portions 20a is not limited to eight. Figure 4 Figure 9 Since the opening 20A of the die 20 for extruding the resin has a shape with convex portions 20a and concave portions 20b on its outer periphery, as the resin 3 is extruded from the gap between the core 30 and the die 20 (see the hatched portion in (a) of Figure 9

[0055] a parison 4 having convex portions 401 and concave portions 402 on its outer surface is formed (see (a) of

[0056] In the convex portions 401, the wall thickness of the parison 4 is relatively thick.

[0057] As Figure 3 and Figure 4 shown, a ventilation duct 34 extending axially from a ventilation port 32 is formed in the center of the core 30. The ventilation duct 34 will be described later.

[0058] In addition, an annular resin path connected to the annular channel 19 is formed between the inner peripheral surface of the die head body 8 and the outer peripheral surface of the core 30.

[0059] The die 20 is disposed at the end of the die head main body 8, and an annular resin path is formed between the inner peripheral surface of the die 20 and the outer peripheral surface of the core 30. And, at the opening 20A of the die 20, an annular preform discharge nozzle port 33 is formed by the die 20 and the core 30 (see Figure 4 (a) thereof). Thus, the resin introduced from the extruder passes through the resin passage, and the preform 4 is discharged from the nozzle port 33.

[0060] In addition, in the present embodiment, the die 20 has a tapered surface on the inner peripheral surface near the opening 20A. And, by moving the core 30 in the vertical direction of the die head main body 8, the gap between the die 20 and the core 30 changes, and the amount of the extruded resin and the thickness of the preform are changed (see Figure 5 ).

[0061] In addition, in the present embodiment, the shape of the core 30 is configured such that the bottom surface is circular, but it is not limited thereto, and it may also be a gear shape or a star shape. In addition, the die 20 may also adopt a structure that can move not only in the vertical direction but also in the horizontal direction. In this way, the gap between the hole on the lower surface of the die 20 and the bottom surface of the core 30 can be adjusted, and the thickness of the preform can be adjusted in the circumferential direction. Thus, a container having different wall thicknesses in the circumferential direction can be manufactured (see Figure 12 ).

[0062] In addition, the preform molding machine 5 has a ventilation duct 22 formed in a mandrel 18 described later and a gas supply source 17 that supplies pressurized cooling gas to the ventilation duct 22.

[0063] The gas supply source 17 supplies the pressurized cooling gas as an air flow to the ventilation duct 22 of the mandrel 18. The ventilation duct 22 leads to the inside of the preform 4. The pressurized cooling gas is, for example, normal temperature air at a specified pressure.

[0064] Therefore, the pressurized cooling gas is blown into the preform 4 from the ventilation port 32 through the ventilation duct 22. As a result, the preform 4 formed by the die head main body 8 can be maintained in a tubular shape.

[0065] (4. Container molding machine) Next, a container molding machine 6 that forms the tubular preform 4 into the shape of a container will be described. As Figure 1 shown, the container molding machine 6 includes a base 60, two container molds 25 provided on the base 60, a driving device 27 having a blow pin 26 corresponding to the diameter of the mouth portion of the formed container 2, and a moving mechanism (not shown) that moves the container molds 25 and the driving device 27 together with the base 60. The container molds 25 are used to sandwich the preform 4 and blow air or the like from the inside of the preform 4 to expand it to form a container shape.

[0066] Specifically, a part of the parison 4 is received in the container mold 25, and high-pressure air is injected from the blow pin 26 into the parison 4 received in the container mold 25, causing the parison 4 to expand into a container shape from the inside and cool, thereby obtaining the container 2.

[0067] In addition, the blow pin 26 can also be arranged in such a way that it passes through the center of the insert core 30 and the mandrel 18. In this case, it can also be configured such that the blow pin can move up and down, and the pressurized cooling gas is inserted and blown out from above the parison 4 clamped by the container mold. In addition, a structure can also be adopted in which, instead of using a blow pin, the pressurized cooling gas is blown out from above the parison 4 through the vent 32 of the core 30 via the vent passage 22.

[0068] In the container mold 25, the inner surface of the concave portion that forms part of the container 2 is formed into the shape of the outer surface of the container 2. In addition, the container mold 25 includes a pair of split molds 29 that can move relative to each other laterally. In addition, the split molds 29 in the present embodiment are composed of a left and right pair, but for example, they can also be composed of three or four.

[0069] After the container mold 25 moves to the lower side of the die head body 8 and the parison 4 is disposed between the pair of split molds 29, the pair of split molds 29 that are separated from each other approach each other, and the parting surfaces come into contact with each other. In the container mold 25 in this state, the parison 4 is expanded to form a container shape.

[0070] In addition, the container molding machine 6 has a vent passage formed in the blow pin 26 and a second gas supply source 28 that supplies pressurized cooling gas to the vent passage.

[0071] The second gas supply source 28 supplies normal-temperature air at a specified pressure as the pressurized cooling gas to the vent passage of the blow pin 26. This vent passage can communicate with the inside of the parison 4 in the container mold 25. Thus, the pressurized cooling gas is blown into the parison 4 through the vent passage at the required timing.

[0072] When the molding of the container 2 based on the container mold 25 is completed, the moving mechanism of the container molding machine 6 moves the container mold 25 away from the lower side of the die head body 8 and moves the next container mold 25 to the lower side of the die head body 8. With this structure, the container 2 can be continuously manufactured.

[0073] <Container manufacturing method> (1. Overall) Next, the container manufacturing method (hereinafter referred to as the direct blow molding method) will be described. The direct blow molding method of the present embodiment mainly includes: (1) a parison molding step of extruding the molten thermoplastic resin 3 into a tubular shape to form the parison 4; (2) a container molding step of clamping the formed parison 4 into the container mold 25 and blowing pressurized cooling gas into the parison 4 in the container mold 25, thereby causing the parison 4 to expand into a container shape and simultaneously cool, thereby obtaining the container 2.

[0074] (2. Parison forming process) As Figure 1 shown, in the parison forming process, the solid resin 3 is introduced from the resin material inlet 11 into the heating cylinder 12. The resin 3 introduced into the heating cylinder 12 is heated by the heat of the heating cylinder 12 and gradually melts. At the same time, the molten resin 3 is transported from the heating cylinder 12 to the die head body 8 under the extrusion force of the extrusion screw 13 driven by the motor 14.

[0075] The molten resin 3 that reaches the die head body 8 passes through the annular channel 19 and is extruded downward through the gap between the die 20 and the core 30 from below the die head body 8. Thereby, a tubular parison 4 is formed.

[0076] In addition, it is also possible to have a mechanism that adjusts the wall thickness in the height direction of the container by adopting a structure capable of controlling the up and down movement of the core 30. When the resin for forming the parison 4 is extruded from the die 20, the core 30 reciprocates up and down under the control of the servo motor 16, so that the gap between the die 20 and the core 30 changes at any time, and the amount of the extruded resin changes. Thereby, it is also possible to realize the extrusion of the parison 4 in which the thick wall and the thin wall are in an alternating state in the height direction (see Figure 5 and Figure 6 ).

[0077] Furthermore, when forming the parison 4, the pressurized cooling gas is blown out from the ventilation duct 22 through the ventilation port 32. This pressurized cooling gas is weakly pressurized (for example, 0.5 - 1.0 kg / cm 2 ), and its air pressure is lower than that of the pressurized cooling gas blown into the inside of the parison 4 in the state clamped by the container mold 25. The purpose is that when the pressurized cooling gas in the ventilation duct 22 is blown into the cavity inside the cylindrical parison 4 in a softened state, the shape of the cylindrical parison 4 will not change substantially.

[0078] (3. Container forming process) Next, as Figure 1 shown, in the container forming process, a pair of split molds 29 are positioned outside the parison 4 in an open state. At this time, the parison 4 is in a state of hanging down from the die. Then, the pair of split molds 29 clamp the parison 4, so that the lower side of the parison 4 is closed. In addition, when clamping, the lower end portion of the parison 4 is cut off.

[0079] Then, the upper end portion of the parison 4 with the lower end portion closed is cut off by a hot cutter (not shown).

[0080] In addition, during the period from the moment when the parison 4 starts to be formed to the moment when the designated portion of the parison 4 is cut off, the pressurized cooling gas is blown out from the ventilation duct 22. In addition, the pressurized cooling gas can also be blown out at a required timing.

[0081] Next, the blow pin 26 of the injection device 27 is inserted into the opening at the upper end of the cut preform 4. Then, compressed air at about 0.39 to 0.49 MPa is blown into the preform 4 with its bottom closed from the air outlet of the air passage of the blow pin 26. As a result, the preform 4 in a semi-solid state at high temperature expands. As a result, the preform 4 expands while the wall thickness becomes thinner, and the preform 4 is formed along the inner surface of the container mold 25.

[0082] At this time, the thick-walled part and the thin-walled part are alternately continuous in the circumferential direction. Therefore, after the preform 4 expands, a shape without unevenness along the container mold is formed on the outside. On the other hand, the thick-walled part forms a shape with convex portions 401 bulging inward and concave portions 402. Therefore, based on the thick-walled part and the thin-walled part, a container with a shape in which the convex portions 201 bulging inward and the non-bulging concave portions 202 are alternately and smoothly continuous is formed in a semi-solid state (see Figure 7 ).

[0083] Next, the container 2 is solidified by cooling the container mold 25. Then, the pair of split molds 29 are separated from each other, and the container 2 is removed from the pair of split molds 29, completing Figure 7 the container 2 shown.

[0084] In addition, as the pressurized cooling gas passing through the air passage 22 and the air passage 34, it is not limited to air, and it may be a gas that does not react with the resin 3 forming the preform 4, such as an inert gas.

[0085] <Container> Figure 7 (b) of is a cross-sectional view of the container of this embodiment. The container 2 has a generally cylindrical shape with a bottom, and the central portion in the height direction is slightly expanded compared to the upper and lower portions. In addition, a mouth portion is formed at the top of the container 2, and an external thread is formed on the outer peripheral surface of the mouth portion. In the container 2, the convex portions 201 bulging inward and the non-bulging concave portions 202 are continuous in the circumferential direction. On the other hand, the outside is formed by a flat surface without unevenness, having a simple outer shape.

[0086] Since the outer peripheral surface of the container 2 thus configured is a flat surface without forming unevenness, it is easy to stick a label on its outer peripheral surface. In addition, by making the container 2 transparent or semi-transparent, since the convex portions 201 bulging inward and the non-bulging concave portions 202 are continuous in the circumferential direction, when observed from the outside, it looks very beautiful and aesthetic due to light reflection and refraction, etc. In addition, since the liquid stored therein can be recognized from the outside, it is suitable as a container for containing cosmetics or drugs.

[0087] In addition, the amount of protrusion of the convex portion 201 that bulges inward can be changed not only according to the shape of the core 30 or the opening 20A of the mold 20, but also according to the vertical movement control of the core 30. That is, this is because by setting the core 30 at a slightly lowered position, the gap between the core 30 and the mold 20 becomes wider, and the amount of resin extruded can be increased.

[0088] In addition, as Figure 8 shown, when the resin for forming the preform 4 is extruded from the mold 20, the core 30 reciprocates vertically under the control of the servo motor 16, so that a container having continuous convex portions 203 and concave portions 204 formed in the height direction of the inner surface of the container 2 can also be formed.

[0089] <Other Embodiments> In addition to the above-described embodiments, the present invention can also adopt the following structures, for example. Figure 9 (a) and (b) of [] are schematic views of a container manufacturing apparatus showing a container manufacturing process according to an embodiment different from the above. Figure 10 , Figure 11 is a view showing a container according to another embodiment. Figure 12 is an explanatory view for explaining the movement of the core of the preform molding machine of the container manufacturing apparatus according to another embodiment.

[0090] (1. Manufacturing Apparatus with a Spiral Strip Molding Machine) As Figure 9 shown in (b) of [], a structure in which a twisting mechanism for twisting the preform is added to the manufacturing apparatus of the above-described embodiment can also be adopted in order to form spiral unevenness or the like on the inner surface.

[0091] As Figure 9 shown in (b) of [], the twisting mechanism 100 includes a pair of arms 102 as clamping portions, an opening / closing mechanism 103, and a rotation motor 104 as a rotating portion.

[0092] The pair of arms 102 are used to grasp the preform 4. As an example, the material of the arms is aluminum, and the outer surface of the arms 102 is covered with Teflon (registered trademark).

[0093] The lower end portions of the respective arms 102 are connected to the opening / closing mechanism 103. When the opening / closing mechanism 103 is driven, the upper end portions of the pair of arms 102 separate and approach, thereby performing the opening / closing operation of the pair of arms 102. Each arm 102 has a shape in which its upper end portion is bent inward. In addition, the arm 102 has a wide shape, and by adopting this shape, the arm 102 can easily grasp the preform 4.

[0094] Then, the arm 102 of the twisting mechanism 100 grasps the lower side portion of the extruded and sagging parison 4, and the lower side portion of the outer peripheral surface of the parison 4 is flattened under the force of the arm 102. Thus, by flattening the lower side portion of the outer peripheral surface of the parison 4, the parison 4 can be tightly grasped by the pair of arms 102.

[0095] Then, in a state where the pair of arms 102 grasp the lower side portion of the parison 4, the rotation motor 104 is driven by a specified rotation speed for a specified rotation angle. Under the drive of the rotation motor 104, the pair of arms 102 rotate around the rotation axis of the rotation motor 104, twisting the parison 4 in the circumferential direction. Therefore, the convex portions 401 and the concave portions 402 extending in the height direction along the inner surface of the parison 4 are in a spiral shape.

[0096] Then, the parison is clamped by the container mold, and the parison is inflated and cooled from the inside by compressed air, so that a container with spiral unevenness can be manufactured.

[0097] Based on the manufacturing apparatus to which the twisting mechanism 100 is added, as Figure 10 、 Figure 11 shown, it is possible to manufacture a container in which the convex portions 201 and the concave portions 202 that bulge in the height direction on the inner surface are continuous and the inner surface has spiral convex portions 201 and concave portions 202.

[0098] (2. Manufacturing apparatus in which the mold and the core can move relative to each other in the horizontal direction) In addition, as Figure 12 shown, a structure in which the mold 20 and the core 30 can move in the horizontal direction is adopted, so that a manufacturing apparatus having a mechanism for adjusting the wall thickness in the circumferential direction of the circle can be obtained. At this time, in addition to adopting a structure in which only the core 30 can move horizontally, a structure in which the rod 50 portion including the mold 20 can move horizontally, or a structure in which the entire mandrel 18 including the core 30 can move horizontally can also be adopted. That is, it is sufficient that the mold 20 and the core 30 can move horizontally relative to each other. As a structure that can move horizontally, as long as it is connected to a servo motor or the like and can control the movement.

[0099] Thereby, a structure in which the core 30 can move relative to the mold 20 in the vertical direction and the horizontal direction is realized. Therefore, the wall thickness of the extruded parison can be adjusted to form a container in which the convex portions and the concave portions that bulge in the height direction on the inner surface are connected and the local wall thickness in the circumferential direction is thin. In addition, it may also be a shape in which the convex portions and the concave portions are continuous in the height direction on the inner surface, and there are wall thickness portions that are thinner than other portions in the height direction and the circumferential direction. By using such a container, when pressing the thin wall thickness portion with a finger or the like, the liquid therein can be extruded.

[0100] (3. Others) As described above, the present invention can adopt the foregoing embodiments, but the present invention is not limited to the foregoing embodiments, and various changes can be made without departing from the scope of the present invention, and equivalents can be used to replace the structures of the embodiments. In addition, many modifications can be made without departing from the basic scope of the present invention to adapt a specific situation or material to the gist of the present invention.

[0101] For example, in the above-described embodiment, a structure in which the core 30 is moved up and down is adopted, but a structure in which the mold 20 is moved up and down can also be considered. In this case, when extruding the parison, the mold 20 is moved up and down, and thus the same effect can be obtained. At this time, for example, a structure in which the rod 50 can be telescoped or the like to enable the mold 20 to be moved up and down can be considered. Therefore, the present invention is not limited to the foregoing embodiments, but includes all embodiments included in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 is a schematic diagram of a container manufacturing apparatus for a container manufacturing process according to an embodiment of the present invention. Figure 2 is a cross-sectional view of a parison molding machine of the container manufacturing apparatus. Figure 3 is a cross-sectional view of a main part of the parison molding machine. Figure 4 is Figure 1 the X-X cross-sectional view in. (a) is a view in which a core is arranged, and (b) is a view not including the core. Figure 5 is an explanatory diagram for explaining the movement of the core of the parison molding machine. Figure 6 is a control diagram for controlling the core of the parison molding machine. Figure 7 is a view of a container according to a first embodiment of the present invention. Figure 8 is a view showing a modified example of the container. Figure 9 is a schematic diagram of a container manufacturing apparatus for a container manufacturing process of other embodiments. Figure 10 is a view showing a modified example of the container. Figure 11 is a view showing a modified example of the container. Figure 12 is an explanatory diagram for explaining the movement of the core of the parison molding machine of the container manufacturing apparatus according to other embodiments. DESCRIPTION OF SYMBOLS

[0103] 1 Direct blow molding apparatus 2 Container 3 Resin 4 parison 5 parison forming machine 6 container forming machine 7 resin material supply section 8 die head body 11 resin material inlet 12 heating cylinder 13 extrusion screw 14 motor 15 mandrel 16 servo motor 17 gas supply source 18 core rod 19 annular channel 20 mold 20A opening part 20a convex part 20b concave part 21 insertion through hole 22 ventilation duct 25 container mold 26 blowing pin 27 driving-in device 28 gas supply source 29 separating mold 30 core 32 ventilation opening 33 nozzle opening 34 ventilation duct 60 base 100 torsion mechanism 101 base 102 arm 103 opening and closing mechanism 104 rotation motor 201 convex part of the container 202 concave part of the container 203 convex part of the container 204 concave part of the container 401 convex part on the outer periphery of the parison 402 concave part on the outer periphery of the parison

Claims

1. A method for manufacturing a container, characterized in that, Comprising: Process A of forming a tubular parison having concavities and convexities on the outer surface; Process B of clamping the parison with a mold; and Process C of expanding the parison from the inside to form a container, wherein, In Process A, the opening of the die from which the resin is extruded has a shape with concavities and convexities on the outer periphery, and the resin is extruded from the die to form a parison having concavities and convexities on the outer surface; Concavities and convexities are formed on the inner surface of the container formed through Process C.

2. The method for manufacturing a container according to claim 1, wherein, In Process A, the opening of the die has a shape in which concave portions and convex portions are alternately and continuously connected in the circumferential direction.

3. The method for manufacturing a container according to claim 2, wherein, In Process A, the opening of the die is formed in a gear shape.

4. The method for manufacturing a container according to claim 2, wherein, In Process A, the concave portions and the convex portions of the opening of the die are smoothly connected.

5. The method for manufacturing a container according to any one of claims 1 to 4, wherein, In Process A, a core is inserted through the center of an insertion hole communicating with the opening of the die, and the resin is extruded from the gap between the opening of the die and the core to form a tubular parison having different wall thicknesses in the circumferential direction.

6. The method for manufacturing a container according to claim 5, wherein, In Process C, the parison clamped by the mold is inflated from the inside by air to form a container having no concavities and convexities on the outer surface and having concavities and convexities with different wall thicknesses in the circumferential direction on the inner surface.

7. The method for manufacturing a container according to claim 1, wherein, In Process A, when the resin for forming the parison is extruded from the die, the core or the die moves up and down to continuously extrude a parison having different wall thicknesses.

8. The method for manufacturing a container according to claim 7, wherein, In Process A, the core or the die moves up and down at a specified interval and with a specified amplitude.

9. The method for manufacturing a container according to claim 8, wherein, In Process A, the core or the die can move up and down to form continuous concavities and convexities over the entire length in the height direction of the inner surface of the container.

10. The method for manufacturing a container according to claim 1, wherein, The formed container is formed with different wall thicknesses in the circumferential direction.

11. The method for manufacturing a container according to claim 10, wherein, The formed container is formed with different wall thicknesses in the height direction.

12. The method for manufacturing a container according to claim 1, wherein, Process A includes a process of clamping the lower end of the parison that sags after being extruded from the die and twisting the parison in the circumferential direction while clamping the lower end of the parison.

13. The method for manufacturing a container according to claim 1, wherein, In Process A, the core is disposed at a position eccentric from the center position of the hole provided in the center of the die, and the wall thickness of the parison extruded from the die is formed such that a part of the peripheral wall is thinner than the other part of the peripheral wall, so that the formed container is formed with different wall thicknesses in the circumferential direction.

14. A container manufacturing device, characterized in that, Comprising: Structure A of forming a tubular parison having concavities and convexities on the outer surface; Structure B of clamping the parison with a mold; And Expand the parison from the inside to form the structure C of the container, wherein, The structure A is a structure in which the opening of the die from which the resin is extruded has a shape with concavities and convexities on the outer circumference, and the resin is extruded from the die to form a parison having concavities and convexities on the outer surface. Concavities and convexities are formed on the inner surface of the formed container.

15. The container manufacturing apparatus according to claim 14, wherein, The opening of the die has a shape in which concave portions and convex portions are alternately and continuously connected in the circumferential direction.

16. The container manufacturing apparatus according to claim 15, wherein, The opening of the die is formed in a gear shape.

17. The container manufacturing apparatus according to claim 15, wherein, The concave portions and the convex portions of the opening of the die are smoothly connected.

18. The container manufacturing apparatus according to any one of claims 14 to 17, wherein, There is a core inserted through the center of the insertion hole communicating with the opening of the die, Resin is extruded from the gap between the opening of the die and the core to form a tubular parison having different wall thicknesses in the circumferential direction.

19. The container manufacturing apparatus according to claim 14, wherein, The core or the die can move up and down, When the resin for forming the parison is extruded from the die, the core or the die moves up and down to continuously extrude a parison having different wall thicknesses.

20. The container manufacturing apparatus according to claim 19, wherein, The core or the die moves up and down at a specified interval and a specified amplitude.

21. The container manufacturing apparatus according to claim 14, wherein, The formed container is formed with different wall thicknesses in the circumferential direction.

22. The container manufacturing apparatus according to claim 21, wherein, The formed container is formed with different wall thicknesses in the height direction.

23. The container manufacturing apparatus according to claim 14, wherein, The structure A has a structure that clamps the lower end of the parison that sags from the extrusion of the die, and twists the parison in the circumferential direction while clamping the lower end of the parison.

24. The container manufacturing apparatus according to claim 14, wherein, The core or the die can move in the horizontal direction.

25. A container, characterized in that, The outer surface is flat, and continuous concavities and convexities are formed in the circumferential direction of the inner surface.

26. The container according to claim 25, wherein, Continuous concavities and convexities are formed over the entire length in the circumferential direction of the inner surface.

27. The container according to claim 25, wherein, The continuous concavities and convexities are in a shape in which concave portions and convex portions are alternately and continuously connected in the circumferential direction.

28. The container according to claim 25, wherein, Continuous concavities and convexities are formed in the height direction of the inner surface.

29. The container according to claim 28, wherein, Continuous concavities and convexities are formed over the entire length in the height direction of the inner surface.

30. The container according to claim 25, wherein, It is formed with different wall thicknesses in the circumferential direction.

31. The container according to claim 30, wherein, It is formed with different wall thicknesses in the height direction.

32. The container according to claim 25, wherein, The continuous concavities and convexities in the circumferential direction of the inner surface of the container are formed in a spiral shape.

Images