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; a step (B) in which the parison is sandwiched by a model; and a step C of expanding the parison from the inside to form the container, in which in the step A, when the resin forming the parison is extruded from the mold, the core moves up and down to continuously extrude parisons of different wall thicknesses, thereby forming irregularities 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 a "die") that extrudes a molten thermoplastic 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, in a conventional direct blow molding apparatus, in order to be able to mold a container with different wall thicknesses, the core can be adjusted up and down to change the thickness of the parison (see Patent Document 1). Further, the direct blow molding apparatus of Patent Document 1 can tilt the core and can adjust the thickness in the circumferential direction of the container.

[0004] In addition, an invention in which a groove is formed on the core in order to form a rib (protrusion) on the inner surface of the container has also been disclosed (see Patent Document 2). The groove of this core extends in the axial direction of the core, and through this groove, a linear rib in the height direction is formed 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 a linear rib in the height direction on the inner surface.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 1

Problems to be Solved by the Invention

[0006] However, although conventional direct blow molding apparatuses can adjust the uniform wall thickness of a container or form a linear rib in the height direction on the inner surface of the container, they cannot manufacture a container having continuous unevenness in the height 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 height direction on the inner surface of the container.

[0007] 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.

[0008] The inventors of the present invention have conducted intensive research to form concavities and convexities on the inner surface of a container. After repeated experiments, the present invention has finally been completed. The present invention is proposed based on the above problems, and one of its aims is to provide a method and a manufacturing apparatus for manufacturing a container having concavities and convexities on the inner surface side.

Means for Solving the Problem

[0009] A container manufacturing method according to an embodiment of the present invention is characterized by including: a step A of forming a tubular parison; a step B of clamping the parison with a mold; and a step C of expanding the parison from the inside to form a container, wherein, in the step A, when the resin for forming the parison is extruded from a mold, a core or the mold moves up and down, and a parison with different wall thicknesses is continuously extruded, so as to form concavities and convexities on the inner surface of the formed container.

[0010] According to this structure, the core or the mold continuously moves up and down, so that the gap between the core and the mold changes, and the amount of resin extruded therefrom also changes. Thereby, the wall thickness of the extruded parison is different in the height direction. In a state where the parison is clamped with a mold, the parison is expanded from the inside by air or the like, so that concavities and convexities can be formed on the inner surface of the container. The concavities and convexities formed by this manufacturing method are formed in the height direction, and concavities and convexities in which concave portions and convex portions are smoothly continuous are formed.

[0011] In addition, in this container manufacturing method, in the 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.

[0012] In addition, in this container manufacturing method, in the step A, the core or the mold can move up and down so as to form continuous concavities and convexities 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 concavities and convexities are formed over the entire length in the height direction of the inner surface of the container.

[0013] In addition, in this container manufacturing method, in the step A, the core or the mold moves up and down so as to form continuous concavities and convexities locally in the height direction of the inner surface of the container, and the core and the mold do not move up and down in other parts so as not to form concavities and convexities. According to this structure, a container can be manufactured in which continuous concavities and convexities are formed locally in the height direction of the inner surface of the container, and the other parts have a uniform wall thickness.

[0014] In addition, this container manufacturing method can form the formed container 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.

[0015] In addition, the method for manufacturing the container can be configured such that the process A includes a process of clamping the lower end of the parison that sags after being extruded from the mold and twisting the parison in the circumferential direction while clamping the lower end of the parison. According to this structure, a container can be manufactured that has unevenness formed on the inner surface of the container and has a spiral pattern.

[0016] In addition, in the method for manufacturing the container, the process A includes a process of forming a tubular parison having ridges on the inner surface. According to this structure, a container can be manufactured that has unevenness formed on the inner surface of the container and has linear ridges in the height direction.

[0017] In addition, in the method for manufacturing the container, in the process A, the core can be disposed at a position eccentric from the center position of the hole provided in the center of the mold, and the wall thickness of the parison extruded from the mold can be formed such that a part of the peripheral wall is thinner than the other part of the peripheral wall, so that the formed container has different wall thicknesses in the circumferential direction.

[0018] 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 expanded from the inside by air or the like, so that a container having different wall thicknesses in the circumferential direction can be formed.

[0019] The container manufacturing apparatus according to one embodiment of the present invention is characterized by including: a structure A for forming a tubular parison; 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 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 different wall thicknesses, so as to form unevenness on the inner surface of the formed container. According to this structure, by using this manufacturing apparatus, a container having unevenness formed on the inner surface can be manufactured.

[0020] In addition, the container manufacturing apparatus can adopt a structure in which the structure A has a structure in which the core or the mold moves up and down at a specified interval and a specified amplitude.

[0021] In addition, the container manufacturing apparatus can adopt a structure in which the structure A has a structure in which the core or the mold moves up and down to form unevenness over the entire length in the height direction of the inner surface of the container.

[0022] In addition, the container manufacturing apparatus can adopt a structure in which the structure A has a structure in which the core or the mold moves up and down to form unevenness locally in the height direction of the inner surface of the container, and the core and the mold do not move up and down in other parts so as not to form unevenness.

[0023] In addition, the structure that can be adopted by the container manufacturing apparatus is such that the formed container has different wall thicknesses in the height direction.

[0024] In addition, the structure that can be adopted by the container manufacturing apparatus is such that the structure A has a structure of clamping the lower end of the parison that sags after being extruded from the mold and twisting the parison in the circumferential direction while clamping the lower end of the parison.

[0025] In addition, the structure that can be adopted by the container manufacturing apparatus is such that the structure A is a structure for forming a tubular parison having ridges on the inner surface.

[0026] In addition, the structure that can be adopted by the container manufacturing apparatus is such that in the structure A, the core is disposed at a position eccentric from the center position of the hole provided in the center of the mold, and has a structure of forming the wall thickness of the parison extruded from the mold such that a part of the circumferential wall is thinner than the other part of the circumferential wall, so that the formed container has different wall thicknesses in the circumferential direction.

[0027] A container according to an embodiment of the present invention is characterized in that the outer surface is flat and continuous unevenness is formed in the height direction of the inner surface. According to this structure, a container having a flat outer surface and continuous unevenness formed in the height direction of the inner surface, which could not be manufactured in the past, can be produced.

[0028] In addition, the unevenness of the container forms continuous unevenness over the entire length in the height direction of the inner surface.

[0029] In addition, the unevenness of the container forms unevenness locally in the height direction of the inner surface and does not form unevenness in other parts.

[0030] In addition, the container has different wall thicknesses in the height direction.

[0031] In addition, the container has ridges formed along the height direction on the inner surface.

[0032] In addition, the ridges of the container are formed in a spiral shape.

[0033] In addition, the container has different wall thicknesses in the circumferential direction.

Effects of the Invention

[0034] The present invention can produce a container having unevenness on the inner surface side. Detailed Embodiment

[0035] <Container Manufacturing Apparatus> Hereinafter, an embodiment of the present invention will be described 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 a container manufacturing process according to a first embodiment of the present invention. Figure 2It is a cross-sectional view of the parison former of the container manufacturing apparatus. Figure 3 It is a cross-sectional view of the main part of the parison former. Figure 4 It is a cross-sectional view taken along the line X-X. Figure 5 It is an explanatory view showing the movement of the core of the parison former. Figure 6 It is a control diagram for controlling the core.

[0036] (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") that can easily manufacture a container having unevenness on the inner surface by direct blow molding.

[0037] As Figure 1 shown, the direct blow molding apparatus 1 includes a parison former 5 that forms a tubular parison 4 and a container former 6 that expands the parison 4 into a container shape to obtain a container 2. Then, the molten resin 3 is extruded into the parison 4 by the parison former 5, and in a state where the parison 4 is clamped in the container former 6, it is inflated with air from the inside of the parison 4 to form a container. In addition, in the direct blow molding apparatus 1, the container former 6 is configured to be movable freely relative to the parison former 5.

[0038] (2. Parison Former) As Figure 1 , Figure 2 shown, the parison former 5 heats the thermoplastic resin 3 and extrudes the resin 3 that has been heated to a molten state into a tubular shape, thereby forming the parison 4. As an example of this embodiment, PET is used as the resin 3, but other thermoplastic resins can also be used.

[0039] The parison former 5 has a die head body 8 for extruding the molten thermoplastic resin into a tubular shape to form the parison 4, and a resin material supply section 7 for supplying the molten resin to the die head body 8.

[0040] The resin material supply section 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.

[0041] The extrusion screw 13 is provided 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. Thereby, the resin located inside the heating cylinder 12 is extruded to the die head body 8.

[0042] (3. Die Head) AsFigure 2 , Figure 3 As shown in Figure 3 , a mandrel 18 that forms a shaft die when 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.

[0043] In addition, an annular die 20 is provided at the end of the die head body 8, and a core 30 that penetrates the die head body 8 and has a front end flush with or protruding from the die 20 is provided.

[0044] The axis of the die head body 8 and the axis of the core 30 are on the same line. The core 30 is connected to one end of a mandrel shaft 15 that penetrates the mandrel 18, and the other end of the mandrel shaft 15 is connected to the end of the die head body 8 on the side opposite to the opening, and is connected to a servo motor 16. The core 30 is configured to be able to move up and down.

[0045] In addition, the servo motor 16 is connected to a control unit (not shown), and by controlling the servo motor 16, the core 30 is controlled to be able to move up and down.

[0046] As shown in Figure 3 and Figure 4 , a ventilation duct 34 that axially extends from a ventilation port 32 is formed in the center of the core 30. The ventilation duct 34 will be described later.

[0047] In addition, an annular resin path that is 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.

[0048] The die 20 is disposed at the end of the die head 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 of the die 20, an annular parison discharge nozzle port 33 is formed by the die 20 and the core 30 (see Figure 4 ). Thus, the resin introduced from the extruder passes through the resin channel, and the parison 4 is discharged from the nozzle port 33.

[0049] In addition, in the present embodiment, the die 20 has a tapered surface on the inner peripheral surface near the opening. And, by moving the core 30 in the vertical direction of the die head body 8, the gap between the die 20 and the core 30 changes, and the amount of extruded resin and the thickness of the parison are changed (see Figure 5 ).

[0050] 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 mold 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 mold 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. Thereby, a container having different wall thicknesses in the circumferential direction can be manufactured (see Figure 12 ).

[0051] In addition, the preform molding machine 5 has a ventilation duct 22 formed in the mandrel 18 described later and a gas supply source 17 that supplies pressurized cooling gas to the ventilation duct 22.

[0052] 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.

[0053] 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 body 8 can be kept tubular.

[0054] (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 mold 25 and the driving device 27 together with the base 60. The container mold 25 is used to sandwich the preform 4 and blow air or the like from the inside of the preform 4 to expand it into the shape of a container.

[0055] Specifically, a part of the preform 4 is housed in the container mold 25, and high-pressure air is sprayed from the blow pin 26 into the preform 4 housed in the container mold 25, so that the preform 4 expands from the inside into the shape of a container and is cooled to obtain the container 2.

[0056] In addition, the blow pin 26 may also be arranged in such a way that it passes through the center of the core 30 and the mandrel 18. In this case, it may also be configured such that the blow pin can move up and down, and the pressurized cooling gas is inserted and blown from above the preform 4 clamped by the container mold. In addition, a structure may be adopted in which, instead of using a blow pin, the pressurized cooling gas is blown from above the preform 4 through the ventilation port 32 of the core 30 via the ventilation duct 22.

[0057] In the container mold 25, the inner surface of the recess that is part of forming the container 2 is formed into the shape of the outer surface of the container 2. Further, the container mold 25 includes a pair of split molds 29 that can move relatively laterally. Further, the split molds 29 in the present embodiment are constituted by a left and right pair, but may be constituted by, for example, three or four.

[0058] After the container mold 25 moves to the lower side of the die head main body 8 and when the preform 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. Inside the container mold 25 in this state, the preform 4 is inflated to form a container shape.

[0059] Further, the container molding machine 6 has an air passage formed in the blow pin 26 and a second gas supply source 28 that supplies pressurized cooling gas to the air passage.

[0060] The second gas supply source 28 supplies normal temperature air at a specified pressure as the pressurized cooling gas to the air passage of the blow pin 26. This air passage can communicate with the inside of the preform 4 inside the container mold 25. Thereby, the pressurized cooling gas is blown into the preform 4 through the air passage at a required timing.

[0061] 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 main body 8 and moves the next container mold 25 to the lower side of the die head main body 8. With this configuration, the container 2 can be continuously manufactured.

[0062] <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 in the present embodiment mainly includes: (1) a preform molding step of extruding the molten thermoplastic resin 3 into a tubular shape to form the preform 4; (2) a container molding step of clamping the formed preform 4 into the container mold 25 and blowing pressurized cooling gas into the preform 4 inside the container mold 25, thereby inflating the preform 4 into a container shape and simultaneously cooling it to obtain the container 2.

[0063] (2. Preform molding step) As Figure 1 shown, in the preform molding step, 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 main body 8 by the extrusion force of the extrusion screw 13 driven by the electric motor 14.

[0064] The molten resin 3 that reaches the die head main body 8 is extruded downward from the die head main body 8 through the annular passage 19. Thereby, the tubular preform 4 is formed.

[0065] At this time, the core 30 reciprocates up and down under the control of the servo motor 16, so that the gap between the mold 20 and the core 30 changes at any time, and the amount of resin extruded changes. Thus, the preform 4 with alternating thick and thin wall thicknesses in the height direction is extruded (see Figure 5 and Figure 6 ).

[0066] In addition, when the preform 4 is formed, the pressurized cooling gas is blown out from the ventilation duct 22 through the ventilation opening 32. This pressurized cooling gas is weakly pressurized (for example, 0.5 to 1.0 kg / cm 2 ), which is lower than the air pressure of the pressurized cooling gas blown into the inside of the preform 4 in the state held 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 preform 4 in a softened state, the shape of the cylindrical preform 4 does not change substantially.

[0067] (3. Container forming process) Next, as Figure 1 shown, a pair of split molds 29 are positioned outside the preform 4 in an open state. At this time, the preform 4 is in a state of hanging down from the mold. Then, the pair of partition molds 29 clamp the preform 4, so that the lower side of the preform 4 is closed. In addition, the lower end portion of the preform 4 is cut off.

[0068] Then, the upper end portion of the preform 4 with the lower end portion closed is cut off by a hot cutting knife (not shown).

[0069] In addition, during the period from the moment when the preform 4 starts to be formed to the moment when the designated portion of the preform 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.

[0070] Next, the blow pin 26 is inserted into the opening at the upper end portion of the cut preform 4. Then, pressurized air of about 0.39 to 0.49 MPa is blown into the preform 4 with the bottom closed from the blow outlet of the ventilation duct 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 in a manner along the inner surface of the container mold 25.

[0071] At this time, the thick wall thickness portion and the thin wall thickness portion are alternately continuous in the height direction. Therefore, after the preform 4 expands, the outer side forms a shape along the container mold. On the other hand, the thick wall thickness portion forms a shape bulging inward. Therefore, based on the thick wall thickness portion and the thin wall thickness portion, a container with a shape in which the convex portions 201 bulging inward and the concave portions 202 not bulging are alternately and smoothly continuous is formed in a semi-solid state (see Figure 7 ).

[0072] 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.

[0073] In addition, as the pressurized cooling gas passing through the air duct 22 and the air duct 34, it is not limited to air, and a gas that does not react with the resin 3 forming the parison 4, such as an inert gas, can also be used.

[0074] <Container> Figure 8 is a longitudinal sectional view of the container of the present embodiment. The container 2 has a bottomed square tube shape, an opening is formed at the top, and an external thread is formed on the outer peripheral surface of the opening. In addition, in the container 2, the convex portions 201 that bulge inward and the concave portions 202 that do not bulge are continuous in the height direction. On the other hand, each outer surface is formed of a flat surface without irregularities, having a simple outer shape.

[0075] Since the outer side surface of the container 2 configured as such is a flat surface without irregularities, it is easy to stick labels and stack. In addition, by making the container 2 transparent or semi-transparent, due to the convex portions that bulge inward and the concave portions that do not bulge being continuous in the height direction, when observed from the outside, it appears very beautiful and aesthetic based on 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.

[0076] In addition, the amount of bulge of the convex portions that bulge inward and the spacing of the convex portions can be changed by controlling the up and down movement of the core 30 described above (see Figure 6 ). For example, Figure 8 (a) of is a container in which the spacing of the convex portions is longer than that of the container 2. In addition, as shown in (b) and (c) of Figure 8 , in addition to the container 2 in which the continuous convex portions are present in the entire height direction, a container in which the convex portions are formed only locally can also be used. In addition, as shown in (d) of Figure 8 , by changing the container mold 25, in addition to the square tube shape, a cylindrical shape, a spherical shape, and a curved shape with the middle portion in the height direction expanded can also be formed.

[0077] <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 the container manufacturing process of an embodiment different from the above. Figure 10 is a Y - Y sectional view. Figure 11 is a view showing a container related to another embodiment. Figure 12 is an explanatory view of the movement of the core of a parison molding machine of a container manufacturing apparatus related to another embodiment.

[0078] (1. Structure with rib formed on the inner surface) The core 30 of the above-described embodiment has a circular bottom surface, but in addition to this, as Figure 10 shown, by using a core 110 having a gear-shaped bottom surface, a container with ribs formed on the inner surface can be manufactured.

[0079] In the core 110, a plurality of grooves 111 are arranged at equal intervals in the circumferential direction of the mandrel 18. The plurality of grooves 111 have the same shape as each other. Each groove 111 opens on both sides in the flow direction of the resin 3 in the annular channel 19. The grooves 111 demarcate a part of the outlet of the annular channel 19.

[0080] In addition, a plurality of air outlets 112 for blowing pressurized cooling gas, an air duct 113 extending from each groove 111 toward the center, and a central annular air duct 114 are formed on the core.

[0081] Furthermore, according to the parison molding machine 5 of the present embodiment, the molten thermoplastic resin is extruded through the annular channel 19 of the die body 8 having the mandrel 18 with grooves 111, thereby forming a tubular parison 4 having ribs 120 on the inner circumference. When forming the cavity 4, an air flow can be blown into the cavity 4 from the ventilation duct of the mandrel 18 through the grooves 111.

[0082] Therefore, the air flow can pass through the grooves 111 so as to flow mainly along the ribs 120 on the inner circumference of the parison 4 (see Figure 9 (a)), and thus the ribs 120 of the parison 4 can be cooled intensively and the shape of the ribs 120 of the parison 4 can be maintained unchanged. For example, when expanding the parison 4 formed as described above into a container shape, the shape change of the ribs 120 can be suppressed, and as a result, ribs 211 with good shape accuracy can be formed on the inner circumference of the container ( Figure 11 (a)). In addition, based on the above air flow, a thin gas layer is formed between the surface of the ribs 120 in the grooves 111 and the inner surface of the grooves 111, so that the thermoplastic resin easily flows in the grooves 111.

[0083] Moreover, by using this manufacturing apparatus, when extruding resin to form the parison 4, the pressurized cooling gas is made to flow along the ribs 120 on the inner circumference of the parison 4 from the air outlets 112 of the mandrel 18 (see Figure 10 ). This is a cooling process for cooling the ribs 120 on the inner surface of the parison. Thereby, the ribs 120 of the parison 4 can be cooled intensively and the shape of the ribs 120 of the parison 4 can be maintained unchanged.

[0084] Therefore, for example, when the parison 4 formed as described above is expanded to form a container shape, the shape change of the rib 120 can be suppressed. As a result, a rib 211 with good shape accuracy can be formed on the inner peripheral surface of the barrel portion of the container shown in (a) of Figure 11 .

[0085] In addition, based on the pressurized cooling gas from the air duct 22, a thin gas layer is formed between the surface of the rib 120 in the groove 111 and the inner surface of the groove 111. Therefore, the thermoplastic resin 3 easily flows in the groove 111. As a result, the shape accuracy of the spiral rib 221 of the container 2 can be further improved.

[0086] Moreover, the air outlet 112 of the air duct 22 is arranged at the bottom of the most upstream side end of the groove 111. Thus, the pressurized cooling gas can start cooling immediately after the rib 120 of the parison 4 is formed.

[0087] In addition, the air outlet 112 of the air duct 22 is formed on the groove forming member which is the member for forming the groove 111. Therefore, the air outlet 112 and the groove 111 can be accurately positioned relative to each other. Thus, the pressurized cooling gas from the air duct 22 can effectively flow along the groove 111. As a result, the shape accuracy of the rib 211 of the container can be further improved.

[0088] A container formed by a manufacturing apparatus with the structure of the core changed becomes a container in which the inner surface ridges are continuous in the height direction and the inner surface has ribs extending in the height direction.

[0089] (2. Manufacturing Apparatus with a Spiral Rib Forming Machine) As Figure 9 shown in (b) of

[0090] As Figure 9 shown in (b) of

[0091] A pair of arms 102 are used to grasp the parison 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).

[0092] The lower end of each arm 102 is connected to the opening and closing mechanism 103. When the opening and closing mechanism 103 is driven, the upper ends of the pair of arms 102 separate and approach, thereby performing the opening and closing action of the pair of arms 102. Each arm 102 has a shape in which its upper end bends inward. In addition, the arm 102 has a relatively wide shape. By adopting this shape, the arm 102 can easily grasp the parison 4.

[0093] 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 action of 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.

[0094] 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, causing the parison 4 to twist in the circumferential direction. For example, if the inner surface of the parison 4 has a rib 120 extending in the height direction, the linear rib becomes a spiral rib.

[0095] 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 ribs can be formed.

[0096] Based on the manufacturing apparatus to which the twisting mechanism 100 is added, a container having convex and concave portions that are continuous in the height direction on the inner surface and having spiral ribs 221 on the inner surface can be manufactured ( Figure 11 of (b)).

[0097] (3. 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 mold 20 or 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, it is sufficient to connect a servo motor or the like to control the movement.

[0098] Thus, 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, and a container is formed in which convex and concave portions that are continuous 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 be a shape in which convex and 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 the thin wall thickness portion is pressed with a finger or the like, the liquid therein can be extruded.

[0099] (4. 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 purpose of the present invention.

[0100] 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 move 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

[0101] 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 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 showing 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 according to other embodiments. Figure 10 is a Y-Y cross-sectional view of a parison molding machine of the container manufacturing apparatus according to other embodiments. Figure 11 is a view showing a container according to other embodiments. 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

[0102] 1 Direct blow molding apparatus 2 Container 3 Resin 4 Parison 5 Parison Forming Machine 6 Container Forming Machine 7 Resin Material Supply Department 8 Die Head Body 11 Resin Material Inlet 12 Heating Cylinder 13 Extrusion Screw 14 Electric Motor 15 Mandrel 16 Servo Motor 17 Gas Supply Source 18 Core Rod 19 Annular Channel 20 Mold 22 Ventilation Duct 25 Container Mold 26 Blow Pin 27 Driving-in Device 28 Gas Supply Source 29 Separating Mold 30 Core 32 Vent 33 Nozzle Opening 34 Ventilation Duct 60 Base 100 Torsion Mechanism 101 Base 102 Arm 103 Opening and Closing Mechanism 104 Rotating Motor 110 Core 111 Groove 112 Blow Outlet 113 Air Duct 114 Annular Air Duct 120 Rib 201 Convex Portion 202 Concave Portion 211 Rib 221 Helical Rib

Claims

1. A method for manufacturing a container, characterized in that Comprising: Process A of forming a tubular parison; 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 the process A, when the resin for forming the parison is extruded from the mold, the core or the mold moves up and down, continuously extruding a parison with different wall thicknesses, Thereby forming unevenness on the inner surface of the formed container.

2. The method for manufacturing a container according to claim 1, wherein, In the process A, the core or the mold moves up and down at a specified interval and with a specified amplitude.

3. The method for manufacturing a container according to claim 2, wherein, The process A can move the core or the mold up and down to form continuous unevenness over the entire length in the height direction of the inner surface of the container.

4. The method for manufacturing a container according to claim 2, wherein, The process A moves the core or the mold up and down to form continuous unevenness locally in the height direction of the inner surface of the container, and does not move the core and the mold up and down in other parts so as not to form unevenness.

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

6. The method for manufacturing a container according to any one of claims 1 to 5, wherein, The process A includes a process of clamping the lower end of the parison that sags from the mold and twisting the parison in the circumferential direction while clamping the lower end of the parison.

7. The method for manufacturing a container according to any one of claims 1 to 5, wherein, The process A includes a process of forming a tubular parison having ridges on the inner surface.

8. The method for manufacturing a container according to any one of claims 1 to 5, wherein, In the process A, the core is disposed at a position eccentric from the center position of the hole provided in the center of the mold, and the wall thickness of the parison extruded from the mold is formed such that a part of the circumferential wall is thinner than the other part of the circumferential wall, so that the formed container is formed with different wall thicknesses in the circumferential direction.

9. A container manufacturing device, characterized in that Comprising: Structure A of forming a tubular parison; Structure B of clamping the parison with a mold; And Structure C of expanding the parison from the inside to form a container, wherein, The structure A is a structure in which when the resin for forming the parison is extruded from the mold, the core or the mold moves up and down, continuously extruding a parison with different wall thicknesses, Thereby forming unevenness on the inner surface of the formed container.

10. The container manufacturing apparatus according to claim 9, wherein, The structure A has a structure of moving the core or the mold up and down at a specified interval and with a specified amplitude.

11. The container manufacturing apparatus according to claim 10, wherein, The structure A has a structure of moving the core or the mold up and down to form unevenness over the entire length in the height direction of the inner surface of the container.

12. The container manufacturing apparatus according to claim 10, wherein, The structure A has a structure of moving the core or the mold up and down to form unevenness locally in the height direction of the inner surface of the container, and not moving the core and the mold up and down in other parts so as not to form unevenness.

13. The container manufacturing apparatus according to claim 9, wherein, The formed container is formed with different wall thicknesses in the height direction.

14. The container manufacturing apparatus according to any one of claims 9 to 13, wherein, the structure A has a structure that clamps the lower end of the parison that sags after being extruded from the mold, and twists the parison in the circumferential direction while clamping the lower end of the parison.

15. The container manufacturing apparatus according to any one of claims 9 to 13, wherein, the structure A has a structure for forming a tubular parison having ridges on the inner surface.

16. The container manufacturing apparatus according to any one of claims 9 to 13, wherein, in the structure A, the core is disposed at a position eccentric from the center position of the hole provided in the center of the mold, and has a structure for forming the wall thickness of the parison extruded from the mold such that a part of the circumferential wall is thinner than the other part of the circumferential wall, so that the formed container has different wall thicknesses in the circumferential direction.

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

18. The container according to claim 17, wherein, continuous concavities and convexities are formed over the entire length in the height direction of the inner surface.

19. The container according to claim 17, wherein, concavities and convexities are formed locally in the height direction of the inner surface, and no concavities and convexities are formed in other parts.

20. The container according to claim 17, wherein, it has different wall thicknesses in the height direction.

21. The container according to any one of claims 17 to 20, wherein, ridges are formed on the inner surface in the height direction.

22. The container according to claim 21, wherein, the ridges are formed in a spiral shape.

23. The container according to any one of claims 17 to 20, wherein, it has different wall thicknesses in the circumferential direction.

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